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Sample records for simple theoretical analysis

  1. Two 27 MHz Simple Inductive Loops, as Hyperthermia Treatment Applicators: Theoretical Analysis and Development

    PubMed Central

    Kouloulias, Vassilis; Karanasiou, Irene; Koutsoupidou, Maria; Matsopoulos, George; Kouvaris, John; Uzunoglu, Nikolaos

    2015-01-01

    Background. Deep heating is still the main subject for research in hyperthermia treatment. Aim. The purpose of this study was to develop and analyze a simple loop as a heating applicator. Methods. The performance of two 27 MHz inductive loop antennas as potential applicators in hyperthermia treatment was studied theoretically as well as experimentally in phantoms. Two inductive loop antennas with radii 7 cm and 9 cm were designed, simulated, and constructed. The theoretical analysis was performed by using Green's function and Bessel's function technique. Experiments were performed with phantoms radiated by the aforementioned loop antennas. Results. The specific absorption rate (SAR) distributions were estimated from the respective local phantom temperature measurements. Comparisons of the theoretical, simulation, and experimental studies showed satisfying agreement. The penetration depth was measured theoretically and experimentally in the range of 2–3.5 cm. Conclusion. The theoretical and experimental analysis showed that current loops are efficient in the case where the peripheral heating of spherical tumor formation located at 2–3.5 cm depth is required. PMID:26649070

  2. A theoretical analysis of steady-state photocurrents in simple silicon diodes

    NASA Technical Reports Server (NTRS)

    Edmonds, L.

    1995-01-01

    A theoretical analysis solves for the steady-state photocurrents produced by a given photo-generation rate function with negligible recombination in simple silicon diodes, consisting of a uniformly doped quasi-neutral region (called 'substrate' below) adjacent to a p-n junction depletion region (DR). Special attention is given to conditions that produce 'funneling' (a term used by the single-eventeffects community) under steady-state conditions. Funneling occurs when carriers are generated so fast that the DR becomes flooded and partially or completely collapses. Some or nearly all of the applied voltage, plus built-in potential normally across the DR, is now across the substrate. This substrate voltage drop affects substrate currents. The steady-state problem can provide some qualitative insights into the more difficult transient problem. First, it was found that funneling can be induced from a distance, i.e., from carriers generated at locations outside of the DR. Secondly, it was found that the substrate can divide into two subregions, with one controlling substrate resistance and the other characterized by ambipolar diffusion. Finally, funneling was found to be more difficult to induce in the p(sup +)/n diode than in the n(sup +)/p diode. The carrier density exceeding the doping density in the substrate and at the DR boundary is not a sufficient condition to collapse a DR.

  3. Theoretical and computational analysis of the quantum radar cross section for simple geometrical targets

    NASA Astrophysics Data System (ADS)

    Brandsema, Matthew J.; Narayanan, Ram M.; Lanzagorta, Marco

    2017-01-01

    The concept of the quantum radar cross section (QRCS) has generated interest due to its promising feature of enhanced side lobe target visibility in comparison to the classical radar cross section. Researchers have simulated the QRCS for very limited geometries and even developed approximations to reduce the computational complexity of the simulations. This paper develops an alternate theoretical framework for calculating the QRCS. This new framework yields an alternative form of the QRCS expression in terms of Fourier transforms. This formulation is much easier to work with mathematically and allows one to derive analytical solutions for various geometries, which provides an explanation for the aforementioned sidelobe advantage. We also verify the resulting equations by comparing with numerical simulations, as well as provide an error analysis of these simulations to ensure the accuracy of the results. Comparison of our simulation results with the analytical solutions reveal that they agree with one another extremely well.

  4. Simple theoretical models for composite rotor blades

    NASA Technical Reports Server (NTRS)

    Valisetty, R. R.; Rehfield, L. W.

    1984-01-01

    The development of theoretical rotor blade structural models for designs based upon composite construction is discussed. Care was exercised to include a member of nonclassical effects that previous experience indicated would be potentially important to account for. A model, representative of the size of a main rotor blade, is analyzed in order to assess the importance of various influences. The findings of this model study suggest that for the slenderness and closed cell construction considered, the refinements are of little importance and a classical type theory is adequate. The potential of elastic tailoring is dramatically demonstrated, so the generality of arbitrary ply layup in the cell wall is needed to exploit this opportunity.

  5. Theoretical and natural strain patterns in ductile simple shear zones

    NASA Astrophysics Data System (ADS)

    Ingles, Jacques

    1985-06-01

    A simple empirical model representing the variation of shear strain throughout a simple shear zone allows us to determine the evolution of finite strain as well as the progressive shape changes of passive markers. Theoretical strain patterns (intensity and orientation of finite strain trajectories, deformed shapes of initially planar, equidimensional and non-equidimensional passive markers) compare remarkably well with patterns observed in natural and experimental zones of ductile simple shear (intensity and orientation of schistosity, shape changes of markers, foliation developed by deformation of markers). The deformed shapes of initially equidimensional and non-equidimensional passive markers is controlled by a coefficient P, the product of (1) the ratio between marker size and shear zone thickness (2) the shear gradient across the zone. For small values of P (approximately P < 2), the original markers change nearly into ellipses, while large values of P lead to " retort" shaped markers. This theoretical study also allows us to predict, throughout a simple shear zone, various relationships between the principal finite strain trajectory, planar passive markers and foliations developed by deformation of initially equidimensional passive markers.

  6. Analysis of Simple Neural Networks

    DTIC Science & Technology

    1988-12-20

    ANALYSIS OF SThlPLE NEURAL NETWORKS Chedsada Chinrungrueng Master’s Report Under the Supervision of Prof. Carlo H. Sequin Department of... Neural Networks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...and guidJ.nce. I have learned a great deal from his teaching, knowledge, and criti- cism. 1. MOTIVATION ANALYSIS OF SIMPLE NEURAL NETWORKS Chedsada

  7. The relationship between local liquid density and force applied on a tip of atomic force microscope: A theoretical analysis for simple liquids

    SciTech Connect

    Amano, Ken-ichi Takahashi, Ohgi; Suzuki, Kazuhiro; Fukuma, Takeshi; Onishi, Hiroshi

    2013-12-14

    The density of a liquid is not uniform when placed on a solid. The structured liquid pushes or pulls a probe employed in atomic force microscopy, as demonstrated in a number of experimental studies. In the present study, the relation between the force on a probe and the local density of a liquid is derived based on the statistical mechanics of simple liquids. When the probe is identical to a solvent molecule, the strength of the force is shown to be proportional to the vertical gradient of ln(ρ{sub DS}) with the local liquid's density on a solid surface being ρ{sub DS}. The intrinsic liquid's density on a solid is numerically calculated and compared with the density reconstructed from the force on a probe that is identical or not identical to the solvent molecule.

  8. Theoretical Aspect of Low Pressure Discharges in Simple Gasses

    DTIC Science & Technology

    1994-03-28

    0+, 0- ,02-, 03, 03+, 03-, electronically excited oxygen, electrons, and possibly clusters . The number possible of reaction channels is huge, and one...which are not simple chemically to begin with, and then which decay into many species of ions and free radicals, this information is not always easy to...radiative decays . Another reaction path is for the atom to recombine into a highly excited atomic state and then radiatively decay to the ground state

  9. A theoretical model of sheath fold morphology in simple shear

    NASA Astrophysics Data System (ADS)

    Reber, Jacqueline E.; Dabrowski, Marcin; Galland, Olivier; Schmid, Daniel W.

    2013-04-01

    Sheath folds are highly non-cylindrical structures often associated with shear zones. The geometry of sheath folds, especially cross-sections perpendicular to the stretching direction that display eye-patterns, have been used in the field to deduce kinematic information such as shear sense and bulk strain type. However, how sheath folds form and how they evolve with increasing strain is still a matter of debate. We investigate the formation of sheath folds around a weak inclusion acting as a slip surface in simple shear by means of an analytical model. We systematically vary the slip surface orientation and shape and evaluate the impact on the evolving eye-pattern. In addition we compare our results to existing classifications. Based on field observations it has been suggested that the shear sense of a shear zone can be determined by knowing the position of the center of an eye-pattern and the closing direction of the corresponding sheath fold. In our modeled sheath folds we can observe for a given strain that the center of the eye-structure is subject to change in height with respect to the upper edge of the outermost closed contour for different cross-sections perpendicular to the shear direction. This results in a large variability in layer thickness, questioning the usefulness of sheath folds as shear sense indicators. The location of the center of the eye structure, however, is largely invariant to the initial configurations of the slip surface as well as to strain. It has been suggested that the ratio of the aspect ratio of the innermost and outermost closed contour in eye-patterns could be linked to the bulk strain type based on filed observations. We apply this classification to our modeled sheath folds and we observe that the values of the aspect ratios of the closed contours within the eye-pattern are dependent on the strain and the cross-section location. The ratio (R') of the aspect ratios of the outermost closed contour (Ryz) and the innermost closed

  10. Simple Numerical Analysis of Longboard Speedometer Data

    ERIC Educational Resources Information Center

    Hare, Jonathan

    2013-01-01

    Simple numerical data analysis is described, using a standard spreadsheet program, to determine distance, velocity (speed) and acceleration from voltage data generated by a skateboard/longboard speedometer (Hare 2012 "Phys. Educ." 47 409-17). This simple analysis is an introduction to data processing including scaling data as well as…

  11. Simple numerical analysis of longboard speedometer data

    NASA Astrophysics Data System (ADS)

    Hare, Jonathan

    2013-11-01

    Simple numerical data analysis is described, using a standard spreadsheet program, to determine distance, velocity (speed) and acceleration from voltage data generated by a skateboard/longboard speedometer (Hare 2012 Phys. Educ. 47 409-17). This simple analysis is an introduction to data processing including scaling data as well as simple numerical differentiation and integration. This is an interesting, fun and instructive way to start to explore data manipulation at GCSE and A-level—analysis and skills so essential for the engineer and scientist.

  12. Simple control-theoretic models of human steering activity in visually guided vehicle control

    NASA Technical Reports Server (NTRS)

    Hess, Ronald A.

    1991-01-01

    A simple control theoretic model of human steering or control activity in the lateral-directional control of vehicles such as automobiles and rotorcraft is discussed. The term 'control theoretic' is used to emphasize the fact that the model is derived from a consideration of well-known control system design principles as opposed to psychological theories regarding egomotion, etc. The model is employed to emphasize the 'closed-loop' nature of tasks involving the visually guided control of vehicles upon, or in close proximity to, the earth and to hypothesize how changes in vehicle dynamics can significantly alter the nature of the visual cues which a human might use in such tasks.

  13. Work Domain Analysis: Theoretical Concepts and Methodology

    DTIC Science & Technology

    2005-02-01

    method to elicit expert knowledge: A case study in the methodology of cognitive task analysis. Human Factors, 40, 254-276. Itoh, J., Sakuma, A...Work Domain Analysis: Theoretical Concepts and Methodology Neelam Naikar, Robyn Hopcroft, and Anna Moylan Air Operations...theoretical and methodological approach for work domain analysis (WDA), the first phase of cognitive work analysis. The report: (1) addresses a number of

  14. Theoretical analysis of ARC constriction

    SciTech Connect

    Stoenescu, M.L.; Brooks, A.W.; Smith, T.M.

    1980-12-01

    The physics of the thermionic converter is governed by strong electrode-plasma interactions (emissions surface scattering, charge exchange) and weak interactions (diffusion, radiation) at the maximum interelectrode plasma radius. The physical processes are thus mostly convective in thin sheaths in front of the electrodes and mostly diffusive and radiative in the plasma bulk. The physical boundaries are open boundaries to particle transfer (electrons emitted or absorbed by the electrodes, all particles diffusing through some maximum plasma radius) and to convective, conductive and radiative heat transfer. In a first approximation the thermionic converter may be described by a one-dimensional classical transport theory. The two-dimensional effects may be significant as a result of the sheath sensitivity to radial plasma variations and of the strong sheath-plasma coupling. The current-voltage characteristic of the converter is thus the result of an integrated current density over the collector area for which the boundary conditions at each r determine the regime (ignited/unignited) of the local current density. A current redistribution strongly weighted at small radii (arc constriction) limits the converter performance and opens questions on constriction reduction possibilities. The questions addressed are the followng: (1) what are the main contributors to the loss of current at high voltage in the thermionic converter; and (2) is arc constriction observable theoretically and what are the conditions of its occurrence. The resulting theoretical problem is formulated and results are given. The converter electrical current is estimated directly from the electron and ion particle fluxes based on the spatial distribution of the electron/ion density n, temperatures T/sub e/, T/sub i/, electrical voltage V and on the knowledge of the transport coefficients. (WHK)

  15. MURR nodal analysis with simple interactive simulation

    NASA Astrophysics Data System (ADS)

    Enani, Mohammad Abdulsamad

    The main goal of this research is to design and produce computer codes that should do a NODAL analysis of the core of Missouri University Research Reactor 'MURR' with a simple neutron transient simulation. These codes should be executed on any of the family of the widely used modern IBM/PC (or IBM/PS) microcomputers (or compatibles). The nodal analysis code should find the power (or flux) distribution inside the reactor core and calculate fuel burnup for each of the fuel elements by using the nodal analysis technique described in chapter 3. The simulator code is a relatively simple, educational aid of MURR reactor kinetics simulation that uses one group point reactor model.

  16. Assessment of the tautomeric population of benzimidazole derivatives in solution: a simple and versatile theoretical-experimental approach

    NASA Astrophysics Data System (ADS)

    Diaz, Carlos; Llovera, Ligia; Echevarria, Lorenzo; Hernández, Florencio E.

    2015-02-01

    Herein, we present a simple and versatile theoretical-experimental approach to assess the tautomeric distribution on 5(6)-aminobenzimidazole (5(6)-ABZ) derivatives in solution via one-photon absorption. The method is based on the optimized weighted sum of the theoretical spectra of the corresponding tautomers. In this article we show how the choice of exchange-correlation functional (XCF) employed in the calculations becomes crucial for the success of the approach. After the systematic analysis of XCFs with different amounts of exact-exchange we found a better performance for B3LYP and PBE0. The direct test of the proposed method on omeprazole, a well-known 5(6)-benzimidazole based pharmacotherapeutic, demonstrate its broader applicability. The proposed approach is expected to find direct applications on the tautomeric analysis of other molecular systems exhibiting similar tautomeric equilibria.

  17. Pure shear and simple shear calcite textures. Comparison of experimental, theoretical and natural data

    USGS Publications Warehouse

    Wenk, H.-R.; Takeshita, T.; Bechler, E.; Erskine, B.G.; Matthies, S.

    1987-01-01

    The pattern of lattice preferred orientation (texture) in deformed rocks is an expression of the strain path and the acting deformation mechanisms. A first indication about the strain path is given by the symmetry of pole figures: coaxial deformation produces orthorhombic pole figures, while non-coaxial deformation yields monoclinic or triclinic pole figures. More quantitative information about the strain history can be obtained by comparing natural textures with experimental ones and with theoretical models. For this comparison, a representation in the sensitive three-dimensional orientation distribution space is extremely important and efforts are made to explain this concept. We have been investigating differences between pure shear and simple shear deformation incarbonate rocks and have found considerable agreement between textures produced in plane strain experiments and predictions based on the Taylor model. We were able to simulate the observed changes with strain history (coaxial vs non-coaxial) and the profound texture transition which occurs with increasing temperature. Two natural calcite textures were then selected which we interpreted by comparing them with the experimental and theoretical results. A marble from the Santa Rosa mylonite zone in southern California displays orthorhombic pole figures with patterns consistent with low temperature deformation in pure shear. A limestone from the Tanque Verde detachment fault in Arizona has a monoclinic fabric from which we can interpret that 60% of the deformation occurred by simple shear. ?? 1987.

  18. Generation of limited-diffraction wave by approximating theoretical X-wave with simple driving

    NASA Astrophysics Data System (ADS)

    Li, Yaqin; Ding, MingYue; Hua, Shaoyan; Ming, Yuchi

    2012-03-01

    X-wave is a particular case of limited diffracting waves which has great potential applications in the enlargement of the field depth in acoustic imaging systems. In practice, the generation of real time X-wave ultrasonic fields is a complex technology which involves precise and specific voltage for the excitations for each distinct array element. In order to simplify the X-wave generating process, L. Castellanos proposed an approach to approximate the X-wave excitations with rectangular pulses. The results suggested the possibility of achieving limited-diffraction waves with relatively simple driving waveforms, which could be implemented with a moderate cost in analogical electronics. In this work, we attempt to improve L. Castellanos's method by calculating the approximation driving pulse not only from rectangular but also triangular driving pulse. The differences between theoretical X-wave signals and driving pulses, related to their excitation effects, are minimized by L2 curve criterion. The driving pulses with the minimal optimization result we chosen. A tradeoff is obtained between the cost of implementation of classical 0-order X-wave and the precision of approximation with the simple pulsed electrical driving. The good agreement of the driving pulse and the result resulting field distributions, with those obtained from the classical X-wave excitations can be justified by the filtering effects induced by the transducer elements in frequency domain. From the simulation results, we can see that the new approach improve the precise of the approximation, the difference between theoretical X-wave and the new approach is lower 10 percent than the difference between theoretical X-wave and rectangular as the driving pulse in simulation.

  19. Theoretical Analysis of Canadian Lifelong Education Development

    ERIC Educational Resources Information Center

    Mukan, Natalia; Barabash, Olena; Busko, Maria

    2014-01-01

    In the article, the problem of Canadian lifelong education development has been studied. The main objectives of the article are defined as theoretical analysis of scientific and pedagogical literature which highlights different aspects of the research problem; periods of lifelong education development; and determination of lifelong learning role…

  20. A simple theoretical framework for understanding heterogeneous differentiation of CD4+ T cells

    PubMed Central

    2012-01-01

    Background CD4+ T cells have several subsets of functional phenotypes, which play critical yet diverse roles in the immune system. Pathogen-driven differentiation of these subsets of cells is often heterogeneous in terms of the induced phenotypic diversity. In vitro recapitulation of heterogeneous differentiation under homogeneous experimental conditions indicates some highly regulated mechanisms by which multiple phenotypes of CD4+ T cells can be generated from a single population of naïve CD4+ T cells. Therefore, conceptual understanding of induced heterogeneous differentiation will shed light on the mechanisms controlling the response of populations of CD4+ T cells under physiological conditions. Results We present a simple theoretical framework to show how heterogeneous differentiation in a two-master-regulator paradigm can be governed by a signaling network motif common to all subsets of CD4+ T cells. With this motif, a population of naïve CD4+ T cells can integrate the signals from their environment to generate a functionally diverse population with robust commitment of individual cells. Notably, two positive feedback loops in this network motif govern three bistable switches, which in turn, give rise to three types of heterogeneous differentiated states, depending upon particular combinations of input signals. We provide three prototype models illustrating how to use this framework to explain experimental observations and make specific testable predictions. Conclusions The process in which several types of T helper cells are generated simultaneously to mount complex immune responses upon pathogenic challenges can be highly regulated, and a simple signaling network motif can be responsible for generating all possible types of heterogeneous populations with respect to a pair of master regulators controlling CD4+ T cell differentiation. The framework provides a mathematical basis for understanding the decision-making mechanisms of CD4+ T cells, and it can be

  1. A simple theoretical model for erbium doped PCF ring lasers design

    NASA Astrophysics Data System (ADS)

    Sánchez-Martín, J. A.; Álvarez, J. M.; Rebolledo, M. A.; Andrés, M. V.; Vallés, J. A.; Martín, J. C.; Berdejo, V.; Díez, A.

    2011-09-01

    In this paper a simple theoretical model is presented where the energy conservation principle is used. The model is based on semi-analytical equations describing the behaviour of an erbium-doped photonic crystal fibre (PCF) inside a ring laser. These semi-analytical equations allow the characterisation of the erbium-doped PCF. Spectral absorption and emission coefficients can be determined through the measurement of the gain in the PCF as a function of pump power attenuation for several fibre lengths by means of a linear fitting. These coefficients are proportional to the erbium concentration and to the corresponding absorption or emission cross section. So if the concentration is known the erbium cross sections can be immediately determined. The model was successfully checked by means of two different home-made erbium doped PCFs. Once the fibres were characterised the values of the spectral absorption and emission coefficients were used to simulate the behaviour of a back propagating ring laser made of each fibre. Passive losses of the components in the cavity were previously calibrated. A good agreement was found between simulated and experimental values of efficiency, pump power threshold and output laser power for a wide set of experimental situations (several values of the input pump power, output coupling factor, laser wavelength and fibre length).

  2. A simple white noise analysis of neuronal light responses.

    PubMed

    Chichilnisky, E J

    2001-05-01

    A white noise technique is presented for estimating the response properties of spiking visual system neurons. The technique is simple, robust, efficient and well suited to simultaneous recordings from multiple neurons. It provides a complete and easily interpretable model of light responses even for neurons that display a common form of response nonlinearity that precludes classical linear systems analysis. A theoretical justification of the technique is presented that relies only on elementary linear algebra and statistics. Implementation is described with examples. The technique and the underlying model of neural responses are validated using recordings from retinal ganglion cells, and in principle are applicable to other neurons. Advantages and disadvantages of the technique relative to classical approaches are discussed.

  3. Simple Analysis of Historical Lime Mortars

    ERIC Educational Resources Information Center

    Pires, Joa~o

    2015-01-01

    A laboratory experiment is described in which a simple characterization of a historical lime mortar is made by the determination of its approximate composition by a gravimetric method. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) are also used for the qualitative characterization of the lime mortar components. These…

  4. Simple yet Hidden Counterexamples in Undergraduate Real Analysis

    ERIC Educational Resources Information Center

    Shipman, Barbara A.; Shipman, Patrick D.

    2013-01-01

    We study situations in introductory analysis in which students affirmed false statements as true, despite simple counterexamples that they easily recognized afterwards. The study draws attention to how simple counterexamples can become hidden in plain sight, even in an active learning atmosphere where students proposed simple (as well as more…

  5. Theoretical analysis of intracortical microelectrode recordings

    PubMed Central

    Lempka, Scott F; Johnson, Matthew D; Moffitt, Michael A; Otto, Kevin J; Kipke, Daryl R; McIntyre, Cameron C

    2011-01-01

    Advanced fabrication techniques have now made it possible to produce microelectrode arrays for recording the electrical activity of a large number of neurons in the intact brain for both clinical and basic science applications. However, the long-term recording performance desired for these applications is hindered by a number of factors that lead to device failure or a poor signal-to-noise ratio (SNR). The goal of this study was to identify factors that can affect recording quality using theoretical analysis of intracortical microelectrode recordings of single-unit activity. Extracellular microelectrode recordings were simulated with a detailed multi-compartment cable model of a pyramidal neuron coupled to a finite element volume conductor head model containing an implanted recording microelectrode. Recording noise sources were also incorporated into the overall modeling infrastructure. The analyses of this study would be very difficult to perform experimentally; however, our model-based approach enabled a systematic investigation of the effects of a large number of variables on recording quality. Our results demonstrate that recording amplitude and noise are relatively independent of microelectrode size, but instead are primarily affected by the selected recording bandwidth, impedance of the electrode-tissue interface, and the density and firing rates of neurons surrounding the recording electrode. This study provides the theoretical groundwork that allows for the design of the microelectrode and recording electronics such that the SNR is maximized. Such advances could help enable the long-term functionality required for chronic neural recording applications. PMID:21775783

  6. Theoretical analysis of intracortical microelectrode recordings

    NASA Astrophysics Data System (ADS)

    Lempka, Scott F.; Johnson, Matthew D.; Moffitt, Michael A.; Otto, Kevin J.; Kipke, Daryl R.; McIntyre, Cameron C.

    2011-08-01

    Advanced fabrication techniques have now made it possible to produce microelectrode arrays for recording the electrical activity of a large number of neurons in the intact brain for both clinical and basic science applications. However, the long-term recording performance desired for these applications is hindered by a number of factors that lead to device failure or a poor signal-to-noise ratio (SNR). The goal of this study was to identify factors that can affect recording quality using theoretical analysis of intracortical microelectrode recordings of single-unit activity. Extracellular microelectrode recordings were simulated with a detailed multi-compartment cable model of a pyramidal neuron coupled to a finite-element volume conductor head model containing an implanted recording microelectrode. Recording noise sources were also incorporated into the overall modeling infrastructure. The analyses of this study would be very difficult to perform experimentally; however, our model-based approach enabled a systematic investigation of the effects of a large number of variables on recording quality. Our results demonstrate that recording amplitude and noise are relatively independent of microelectrode size, but instead are primarily affected by the selected recording bandwidth, impedance of the electrode-tissue interface and the density and firing rates of neurons surrounding the recording electrode. This study provides the theoretical groundwork that allows for the design of the microelectrode and recording electronics such that the SNR is maximized. Such advances could help enable the long-term functionality required for chronic neural recording applications.

  7. Analysis of a theoretically optimized transonic airfoil

    NASA Technical Reports Server (NTRS)

    Lores, M. E.; Burdges, K. P.; Shrewsbury, G. D.

    1978-01-01

    Numerical optimization was used in conjunction with an inviscid, full potential equation, transonic flow analysis computer code to design an upper surface contour for a conventional airfoil to improve its supercritical performance. The modified airfoil was tested in a compressible flow wind tunnel. The modified airfoil's performance was evaluated by comparison with test data for the baseline airfoil and for an airfoil developed by optimization of leading edge of the baseline airfoil. While the leading edge modification performed as expected, the upper surface re-design did not produce all of the expected performance improvements. Theoretical solutions computed using a full potential, transonic airfoil code corrected for viscosity were compared to experimental data for the baseline airfoil and the upper surface modification. These correlations showed that the theory predicted the aerodynamics of the baseline airfoil fairly well, but failed to accurately compute drag characteristics for the upper surface modification.

  8. Theoretical analysis of impact in composite plates

    NASA Technical Reports Server (NTRS)

    Moon, F. C.

    1973-01-01

    The calculated stresses and displacements induced anisotropic plates by short duration impact forces are presented. The theoretical model attempts to model the response of fiber composite turbine fan blades to impact by foreign objects such as stones and hailstones. In this model the determination of the impact force uses the Hertz impact theory. The plate response treats the laminated blade as an equivalent anisotropic material using a form of Mindlin's theory for crystal plates. The analysis makes use of a computational tool called the fast Fourier transform. Results are presented in the form of stress contour plots in the plane of the plate for various times after impact. Examination of the maximum stresses due to impact versus ply layup angle reveals that the + or - 15 deg layup angle gives lower flexural stresses than 0 deg, + or - 30 deg and + or - 45 deg. cases.

  9. Courage and nursing practice: a theoretical analysis.

    PubMed

    Lindh, Inga-Britt; Barbosa da Silva, António; Berg, Agneta; Severinsson, Elisabeth

    2010-09-01

    This article aims to deepen the understanding of courage through a theoretical analysis of classical philosophers' work and a review of published and unpublished empirical research on courage in nursing. The authors sought answers to questions regarding how courage is understood from a philosophical viewpoint and how it is expressed in nursing actions. Four aspects were identified as relevant to a deeper understanding of courage in nursing practice: courage as an ontological concept, a moral virtue, a property of an ethical act, and a creative capacity. The literature review shed light on the complexity of the concept of courage and revealed some lack of clarity in its use. Consequently, if courage is to be used consciously to influence nurses' ethical actions it seems important to recognize its specific features. The results suggest it is imperative to foster courage among nurses and student nurses to prepare them for ethical, creative action and further the development of professional nursing practices.

  10. Free radical scavenging and COX-2 inhibition by simple colon metabolites of polyphenols: A theoretical approach.

    PubMed

    Amić, Ana; Marković, Zoran; Marković, Jasmina M Dimitrić; Jeremić, Svetlana; Lučić, Bono; Amić, Dragan

    2016-12-01

    Free radical scavenging and inhibitory potency against cyclooxygenase-2 (COX-2) by two abundant colon metabolites of polyphenols, i.e., 3-hydroxyphenylacetic acid (3-HPAA) and 4-hydroxyphenylpropionic acid (4-HPPA) were theoretically studied. Different free radical scavenging mechanisms are investigated in water and pentyl ethanoate as a solvent. By considering electronic properties of scavenged free radicals, hydrogen atom transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms are found to be thermodynamically probable and competitive processes in both media. The Gibbs free energy change for reaction of inactivation of free radicals indicates 3-HPAA and 4-HPPA as potent scavengers. Their reactivity toward free radicals was predicted to decrease as follows: hydroxyl>alkoxyls>phenoxyl≈peroxyls>superoxide. Shown free radical scavenging potency of 3-HPAA and 4-HPPA along with their high μM concentration produced by microbial colon degradation of polyphenols could enable at least in situ inactivation of free radicals. Docking analysis with structural forms of 3-HPAA and 4-HPPA indicates dianionic ligands as potent inhibitors of COX-2, an inducible enzyme involved in colon carcinogenesis. Obtained results suggest that suppressing levels of free radicals and COX-2 could be achieved by 3-HPAA and 4-HPPA indicating that these compounds may contribute to reduced risk of colon cancer development.

  11. Information-Theoretical Complexity Analysis of Selected Elementary Chemical Reactions

    NASA Astrophysics Data System (ADS)

    Molina-Espíritu, M.; Esquivel, R. O.; Dehesa, J. S.

    We investigate the complexity of selected elementary chemical reactions (namely, the hydrogenic-abstraction reaction and the identity SN2 exchange reaction) by means of the following single and composite information-theoretic measures: disequilibrium (D), exponential entropy(L), Fisher information (I), power entropy (J), I-D, D-L and I-J planes and Fisher-Shannon (FS) and Lopez-Mancini-Calbet (LMC) shape complexities. These quantities, which are functionals of the one-particle density, are computed in both position (r) and momentum (p) spaces. The analysis revealed that the chemically significant regions of these reactions can be identified through most of the single information-theoretic measures and the two-component planes, not only the ones which are commonly revealed by the energy, such as the reactant/product (R/P) and the transition state (TS), but also those that are not present in the energy profile such as the bond cleavage energy region (BCER), the bond breaking/forming regions (B-B/F) and the charge transfer process (CT). The analysis of the complexities shows that the energy profile of the abstraction reaction bears the same information-theoretical features of the LMC and FS measures, however for the identity SN2 exchange reaction does not hold a simple behavior with respect to the LMC and FS measures. Most of the chemical features of interest (BCER, B-B/F and CT) are only revealed when particular information-theoretic aspects of localizability (L or J), uniformity (D) and disorder (I) are considered.

  12. Theoretical Analysis of the F1-ATPase Experimental Data

    PubMed Central

    Perez-Carrasco, Ruben; Sancho, J.M.

    2010-01-01

    Abstract F1-ATPase is a rotatory molecular motor fueled by ATP nucleotides. Different loads can be attached to the motor axis to show that it rotates in main discrete steps of 120° with substeps of ∼80° and 40°. Experimental data show the dependence on the mean rotational velocity ω with respect to the external control parameters: the nucleotide concentration [ATP] and the friction of the load γL. In this work we present a theoretical analysis of the experimental data whose main results are: 1), A derivation of a simple analytical formula for ω([ATP], γL) that compares favorably with experiments; 2), The introduction of a two-state flashing ratchet model that exhibits experimental phenomenology of a greater specificity than has been, to our knowledge, previously available; 3), The derivation of an argument to obtain the values of the substep sizes; 4), An analysis of the energy constraints of the model; and 5), The theoretical analysis of the coupling ratio between the ATP consumed and the success of a forward step. We also discuss the compatibility of our approach with recent experimental observations. PMID:20513403

  13. Theoretical Analysis of Rain Attenuation Probability

    NASA Astrophysics Data System (ADS)

    Roy, Surendra Kr.; Jha, Santosh Kr.; Jha, Lallan

    2007-07-01

    Satellite communication technologies are now highly developed and high quality, distance-independent services have expanded over a very wide area. As for the system design of the Hokkaido integrated telecommunications(HIT) network, it must first overcome outages of satellite links due to rain attenuation in ka frequency bands. In this paper theoretical analysis of rain attenuation probability on a slant path has been made. The formula proposed is based Weibull distribution and incorporates recent ITU-R recommendations concerning the necessary rain rates and rain heights inputs. The error behaviour of the model was tested with the loading rain attenuation prediction model recommended by ITU-R for large number of experiments at different probability levels. The novel slant path rain attenuastion prediction model compared to the ITU-R one exhibits a similar behaviour at low time percentages and a better root-mean-square error performance for probability levels above 0.02%. The set of presented models exhibits the advantage of implementation with little complexity and is considered useful for educational and back of the envelope computations.

  14. Interaction of Simple Ions with Water: Theoretical Models for the Study of Ion Hydration

    ERIC Educational Resources Information Center

    Gancheff, Jorge S.; Kremer, Carlos; Ventura, Oscar N.

    2009-01-01

    A computational experiment aimed to create and systematically analyze models of simple cation hydrates is presented. The changes in the structure (bond distances and angles) and the electronic density distribution of the solvent and the thermodynamic parameters of the hydration process are calculated and compared with the experimental data. The…

  15. Simple Sensitivity Analysis for Orion GNC

    NASA Technical Reports Server (NTRS)

    Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar

    2013-01-01

    The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch.We describe in this paper a sensitivity analysis tool (Critical Factors Tool or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.

  16. Simple Low Level Features for Image Analysis

    NASA Astrophysics Data System (ADS)

    Falcoz, Paolo

    As human beings, we perceive the world around us mainly through our eyes, and give what we see the status of “reality”; as such we historically tried to create ways of recording this reality so we could augment or extend our memory. From early attempts in photography like the image produced in 1826 by the French inventor Nicéphore Niépce (Figure 2.1) to the latest high definition camcorders, the number of recorded pieces of reality increased exponentially, posing the problem of managing all that information. Most of the raw video material produced today has lost its memory augmentation function, as it will hardly ever be viewed by any human; pervasive CCTVs are an example. They generate an enormous amount of data each day, but there is not enough “human processing power” to view them. Therefore the need for effective automatic image analysis tools is great, and a lot effort has been put in it, both from the academia and the industry. In this chapter, a review of some of the most important image analysis tools are presented.

  17. Comparing a simple theoretical model for protein folding with all-atom molecular dynamics simulations.

    PubMed

    Henry, Eric R; Best, Robert B; Eaton, William A

    2013-10-29

    Advances in computing have enabled microsecond all-atom molecular dynamics trajectories of protein folding that can be used to compare with and test critical assumptions of theoretical models. We show that recent simulations by the Shaw group (10, 11, 14, 15) are consistent with a key assumption of an Ising-like theoretical model that native structure grows in only a few regions of the amino acid sequence as folding progresses. The distribution of mechanisms predicted by simulating the master equation of this native-centric model for the benchmark villin subdomain, with only two adjustable thermodynamic parameters and one temperature-dependent kinetic parameter, is remarkably similar to the distribution in the molecular dynamics trajectories.

  18. Comparisons Between Experimental Transport Analysis and Theoretical Modeling on LHD

    NASA Astrophysics Data System (ADS)

    Yamazaki, Kozo; LHD Group

    2000-10-01

    Helical plasma confinement system has a great advantage in producing steady-state high performance plasmas with built-in divertor. For the experimental analysis and predictive simulation of helical and tokamak plasmas, a simulation code TOTAL (TOroidal Transport Analysis Linkage) has been developed and is applied to the Large Helical Device (LHD, R=3.6 ~3.9m, B<3.0T ) experiments. In the LHD experiment, the global plasma confinement is ~1.5-2 times better than the well-known confinement scaling laws, and effective transport diffusivity is same order of magnitude of neoclassical ion transport with the assumption of Ti=Te. The radial electric field has been measured and roughly agrees with theoretical neoclassical values. The simple drift wave transport models are also compared with experimental values. The impurity dynamics are calculated using predictive part of the TOTAL code, and compared with the "breathing plasma" dynamics, and the role of high-Z impurity are clarified. For the analysis of high beta plasmas, local ballooning mode analysis will be added in this TOTAL code, and optimized configurations for the future MHR reactor will be searched.

  19. Theoretical investigation of the synchronous totally asymmetric simple exclusion process with a roundabout

    NASA Astrophysics Data System (ADS)

    Chen, X.; Zhang, Y.; Liu, Y.; Xiao, S.

    2017-02-01

    The roundabout in a one-dimensional system is studied employing the synchronous totally asymmetric simple exclusion process. At special sites far from boundaries, particles can attach to and detach from the system irreversibly with respective probabilities p and q. When the system is in a steady station, seven stationary phases are possible. The results of simulations agree well with analytical calculations. The stable state of the low-density/maximal-current/high-density phase corresponds to a critical point and may transfer to six other phases.

  20. [Rapid spectrochemical qualitative analysis of simple OMA system].

    PubMed

    Yang, C; Lin, Y; Xu, H; Wen, X; Lin, L

    1997-10-01

    Simple optical multichannel analyzer (OMA) system which is formed by ordinary one dimension CCD camera, spectrograph and microcomputer was introduced in this paper. Spectrochemical analysis feasible of this OMA system was studied. The applied software programed, by us can realize wavelength calibration, spectral line identification and give out automatically the results of qualitative and semidefinite quantity analysis.

  1. Theoretical and experimental evidence of Fano-like resonances in simple monomode photonic circuits

    NASA Astrophysics Data System (ADS)

    Mouadili, A.; El Boudouti, E. H.; Soltani, A.; Talbi, A.; Akjouj, A.; Djafari-Rouhani, B.

    2013-04-01

    A simple photonic device consisting of two dangling side resonators grafted at two sites on a waveguide is designed in order to obtain sharp resonant states inside the transmission gaps without introducing any defects in the structure. This results from an internal resonance of the structure when such a resonance is situated in the vicinity of a zero of transmission or placed between two zeros of transmission, the so-called Fano resonances. A general analytical expression for the transmission coefficient is given for various systems of this kind. The amplitude of the transmission is obtained following the Fano form. The full width at half maximum of the resonances as well as the asymmetric Fano parameter are discussed explicitly as function of the geometrical parameters of the system. In addition to the usual asymmetric Fano resonance, we show that this system may exhibit an electromagnetic induced transparency resonance as well as well as a particular case where such resonances collapse in the transmission coefficient. Also, we give a comparison between the phase of the determinant of the scattering matrix, the so-called Friedel phase, and the phase of the transmission amplitude. The analytical results are obtained by means of the Green's function method, whereas the experiments are carried out using coaxial cables in the radio-frequency regime. These results should have important consequences for designing integrated devices such as narrow-frequency optical or microwave filters and high-speed switches. This system is proposed as a simpler alternative to coupled-micoresonators.

  2. A Simple Theoretical Model for the Mean Rainfall Field of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Langousis, A.; Veneziano, D.

    2006-12-01

    We develop a simple model for the mean rainfall intensity profile in tropical cyclones (TCs) before landfall. The model assumes that rainfall is caused primarily by condensation of the humid outflow at the top of the TC boundary layer. This upward-directed flux originates from convergence of the horizontal winds in the boundary layer. The model combines Holland's (1980) representation of the tangential wind speed in the main vortex, an Ekman-type solution for the horizontal and vertical wind profiles inside the TC boundary layer, and moist air thermodynamics to estimate how the mean rainrate i depends on radial distance r from the low pressure center and azimuth b relative to the direction of motion. We start by studying the axisymmetric component i(r), which is also the mean rainrate profile for zero translational velocity. i(r) depends on the maximum pressure deficit DP (or the maximum tangential wind speed Vmax), Holland's B parameter, the radius of maximum winds Rwind, and the depth-averaged temperature in the boundary layer T. The mean rainrate is zero for r = 0, increases to a maximum imax at a distance Rrain somewhat larger than Rwind, and then decays to zero in an almost exponential way. More intense cyclones tend to have lower Rrain and higher imax. The difference Rrain-Rwind is higher for tangential wind profiles that are more picked around Rwind. Such wind profiles are generally associated with more intense cyclones and higher B values. When cyclones in the Northern hemisphere move, the mean rainrate intensifies in the north-east quadrant relative to the direction of motion and de-intesifies in the south-west quadrant. These azimuthal effects are stronger for faster-moving storms. For preliminary validation, we compare model estimates of i(r) under representative parameters with ensemble averages from 548 CAT12 and 212 CAT35 TCs extracted from the TRMM dataset (Lonfat et al., Mon. Wea. Rev. 132 (2004): 1645-1660). The model reproduces very well the shape

  3. Theoretical analysis of the EWEC report

    NASA Technical Reports Server (NTRS)

    1976-01-01

    This analytic investigation shows how the electromagnetic wave energy conversion (EWEC) device, as used for solar-to-electric power conversion, is significantly different from solar cells, with respect to principles of operation. An optimistic estimate of efficiency is about 80% for a full-wave rectifying configuration with solar radiation normally incident. This compares favorably with the theoretical maximum for a CdTe solar cell (23.5%), as well as with the efficiencies of more familiar cells: Si (19.5%), InP (21.5%), and GaAs (23%). Some key technological issues that must be resolved before the EWEC device can be realized are identified. Those issues include: the fabrication of a pn semi-conductor junction with no permittivity resonances in the optical band; and the efficient channeling of the power received by countless microscopic horn antennas through a relatively few number of wires.

  4. Theoretical and observational analysis of spacecraft fields

    NASA Technical Reports Server (NTRS)

    Neubauer, F. M.; Schatten, K. H.

    1972-01-01

    In order to investigate the nondipolar contributions of spacecraft magnetic fields a simple magnetic field model is proposed. This model consists of randomly oriented dipoles in a given volume. Two sets of formulas are presented which give the rms-multipole field components, for isotropic orientations of the dipoles at given positions and for isotropic orientations of the dipoles distributed uniformly throughout a cube or sphere. The statistical results for an 8 cu m cube together with individual examples computed numerically show the following features: Beyond about 2 to 3 m distance from the center of the cube, the field is dominated by an equivalent dipole. The magnitude of the magnetic moment of the dipolar part is approximated by an expression for equal magnetic moments or generally by the Pythagorean sum of the dipole moments. The radial component is generally greater than either of the transverse components for the dipole portion as well as for the nondipolar field contributions.

  5. Category Theoretic Analysis of Hierarchical Protein Materials and Social Networks

    PubMed Central

    Spivak, David I.; Giesa, Tristan; Wood, Elizabeth; Buehler, Markus J.

    2011-01-01

    Materials in biology span all the scales from Angstroms to meters and typically consist of complex hierarchical assemblies of simple building blocks. Here we describe an application of category theory to describe structural and resulting functional properties of biological protein materials by developing so-called ologs. An olog is like a “concept web” or “semantic network” except that it follows a rigorous mathematical formulation based on category theory. This key difference ensures that an olog is unambiguous, highly adaptable to evolution and change, and suitable for sharing concepts with other olog. We consider simple cases of beta-helical and amyloid-like protein filaments subjected to axial extension and develop an olog representation of their structural and resulting mechanical properties. We also construct a representation of a social network in which people send text-messages to their nearest neighbors and act as a team to perform a task. We show that the olog for the protein and the olog for the social network feature identical category-theoretic representations, and we proceed to precisely explicate the analogy or isomorphism between them. The examples presented here demonstrate that the intrinsic nature of a complex system, which in particular includes a precise relationship between structure and function at different hierarchical levels, can be effectively represented by an olog. This, in turn, allows for comparative studies between disparate materials or fields of application, and results in novel approaches to derive functionality in the design of de novo hierarchical systems. We discuss opportunities and challenges associated with the description of complex biological materials by using ologs as a powerful tool for analysis and design in the context of materiomics, and we present the potential impact of this approach for engineering, life sciences, and medicine. PMID:21931622

  6. A theoretical analysis of basin-scale groundwater temperature distribution

    NASA Astrophysics Data System (ADS)

    An, Ran; Jiang, Xiao-Wei; Wang, Jun-Zhi; Wan, Li; Wang, Xu-Sheng; Li, Hailong

    2015-03-01

    The theory of regional groundwater flow is critical for explaining heat transport by moving groundwater in basins. Domenico and Palciauskas's (1973) pioneering study on convective heat transport in a simple basin assumed that convection has a small influence on redistributing groundwater temperature. Moreover, there has been no research focused on the temperature distribution around stagnation zones among flow systems. In this paper, the temperature distribution in the simple basin is reexamined and that in a complex basin with nested flow systems is explored. In both basins, compared to the temperature distribution due to conduction, convection leads to a lower temperature in most parts of the basin except for a small part near the discharge area. There is a high-temperature anomaly around the basin-bottom stagnation point where two flow systems converge due to a low degree of convection and a long travel distance, but there is no anomaly around the basin-bottom stagnation point where two flow systems diverge. In the complex basin, there are also high-temperature anomalies around internal stagnation points. Temperature around internal stagnation points could be very high when they are close to the basin bottom, for example, due to the small permeability anisotropy ratio. The temperature distribution revealed in this study could be valuable when using heat as a tracer to identify the pattern of groundwater flow in large-scale basins. Domenico PA, Palciauskas VV (1973) Theoretical analysis of forced convective heat transfer in regional groundwater flow. Geological Society of America Bulletin 84:3803-3814

  7. LHD Plasma Modeling and Theoretical Analysis

    NASA Astrophysics Data System (ADS)

    Yamazaki, Kozo; Nakajima, Noriyoshi; Murakami, Sadayoshi; Yokoyama, Masayuki

    The transport/heating modeling and equilibrium/stability analysis have been carried out for LHD (Large Helical Device) plasmas. A new simulation code TOTAL (TOroidal Transport Analysis Linkage) is developed, which consists of the 3-dimensional equilibrium code VMEC including bootstrap current and 1-dimensional transport code HTRANS including helical-ripple transport determined as well as anomalous transport. This code clarified the favorable effect of bootstrap current on the neoclassical confinement in LHD. The 3-dimensional stability analysis using CAS3D code has been done and clarified the ballooning mode structure peculiar to the LHD high-beta plasmas. The 5-dimensional simulation code has been developed to analyze the NBI or ECH heating power depositions in LHD plasmas, and the particle orbit effects of high-energy particles are clarified. The plasma rotation analysis is also carried out related to the possibility of the electric-field transition and the plasma confinement improvement in LHD.

  8. Theoretical analysis of HVAC duct hanger systems

    NASA Technical Reports Server (NTRS)

    Miller, R. D.

    1987-01-01

    Several methods are presented which, together, may be used in the analysis of duct hanger systems over a wide range of frequencies. The finite element method (FEM) and component mode synthesis (CMS) method are used for low- to mid-frequency range computations and have been shown to yield reasonably close results. The statistical energy analysis (SEA) method yields predictions which agree with the CMS results for the 800 to 1000 Hz range provided that a sufficient number of modes participate. The CMS approach has been shown to yield valuable insight into the mid-frequency range of the analysis. It has been demonstrated that it is possible to conduct an analysis of a duct/hanger system in a cost-effective way for a wide frequency range, using several methods which overlap for several frequency bands.

  9. A theoretical analysis of vertical flow equilibrium

    SciTech Connect

    Yortsos, Y.C.

    1992-01-01

    The assumption of Vertical Flow Equilibrium (VFE) and of parallel flow conditions, in general, is often applied to the modeling of flow and displacement in natural porous media. However, the methodology for the development of the various models is rather intuitive, and no rigorous method is currently available. In this paper, we develop an asymptotic theory using as parameter the variable R{sub L} = (L/H){radical}(k{sub V})/(k{sub H}). It is rigorously shown that present models represent the leading order term of an asymptotic expansion with respect to 1/R{sub L}{sup 2}. Although this was numerically suspected, it is the first time that is is theoretically proved. Based on the general formulation, a series of models are subsequently obtained. In the absence of strong gravity effects, they generalize previous works by Zapata and Lake (1981), Yokoyama and Lake (1981) and Lake and Hirasaki (1981), on immiscible and miscible displacements. In the limit of gravity-segregated flow, we prove conditions for the fluids to be segregated and derive the Dupuit and Dietz (1953) approximations. Finally, we also discuss effects of capillarity and transverse dispersion.

  10. Catalytic efficiency of enzymes: a theoretical analysis.

    PubMed

    Hammes-Schiffer, Sharon

    2013-03-26

    This brief review analyzes the underlying physical principles of enzyme catalysis, with an emphasis on the role of equilibrium enzyme motions and conformational sampling. The concepts are developed in the context of three representative systems, namely, dihydrofolate reductase, ketosteroid isomerase, and soybean lipoxygenase. All of these reactions involve hydrogen transfer, but many of the concepts discussed are more generally applicable. The factors that are analyzed in this review include hydrogen tunneling, proton donor-acceptor motion, hydrogen bonding, pKa shifting, electrostatics, preorganization, reorganization, and conformational motions. The rate constant for the chemical step is determined primarily by the free energy barrier, which is related to the probability of sampling configurations conducive to the chemical reaction. According to this perspective, stochastic thermal motions lead to equilibrium conformational changes in the enzyme and ligands that result in configurations favorable for the breaking and forming of chemical bonds. For proton, hydride, and proton-coupled electron transfer reactions, typically the donor and acceptor become closer to facilitate the transfer. The impact of mutations on the catalytic rate constants can be explained in terms of the factors enumerated above. In particular, distal mutations can alter the conformational motions of the enzyme and therefore the probability of sampling configurations conducive to the chemical reaction. Methods such as vibrational Stark spectroscopy, in which environmentally sensitive probes are introduced site-specifically into the enzyme, provide further insight into these aspects of enzyme catalysis through a combination of experiments and theoretical calculations.

  11. A theoretical analysis of the electrogastrogram (EGG).

    PubMed

    Calder, Stefan; Cheng, Leo K; Peng Du

    2014-01-01

    In this study, a boundary element model was developed to investigate the relationship between the gastric electrical activity, also known as slow waves, and the electrogastrogram (EGG). A dipole was calculated to represent the equivalent net activity of gastric slow waves. The dipole was then placed in an anatomically-realistic torso model to simulate EGG. The torso model was constructed from a laser-scanned geometry of an adult male torso phantom with 190 electrode sites equally distributed around the torso so that simulated EGG could be directly compared between the physical model and the mathematical model. The results were analyzed using the Fast Fourier Transforms (FFT), spatial distribution of EGG potential and a resultant EGG based on a 3-lead configuration. The FFT results showed both the dipole and EGG contained identical dominant frequency component of 3 cycles per minute (cpm), with this result matching known physiological phenomenon. The -3 dB point of the EGG was 110 mm from the region directly above the dipole source. Finally, the results indicated that electrode coupling could theoretically be used in a similar fashion to ECG coupling to gain greater understanding of how EGG correlate to gastric slow waves.

  12. Landscape analysis: Theoretical considerations and practical needs

    USGS Publications Warehouse

    Godfrey, A.E.; Cleaves, E.T.

    1991-01-01

    Numerous systems of land classification have been proposed. Most have led directly to or have been driven by an author's philosophy of earth-forming processes. However, the practical need of classifying land for planning and management purposes requires that a system lead to predictions of the results of management activities. We propose a landscape classification system composed of 11 units, from realm (a continental mass) to feature (a splash impression). The classification concerns physical aspects rather than economic or social factors; and aims to merge land inventory with dynamic processes. Landscape units are organized using a hierarchical system so that information may be assembled and communicated at different levels of scale and abstraction. Our classification uses a geomorphic systems approach that emphasizes the geologic-geomorphic attributes of the units. Realm, major division, province, and section are formulated by subdividing large units into smaller ones. For the larger units we have followed Fenneman's delineations, which are well established in the North American literature. Areas and districts are aggregated into regions and regions into sections. Units smaller than areas have, in practice, been subdivided into zones and smaller units if required. We developed the theoretical framework embodied in this classification from practical applications aimed at land use planning and land management in Maryland (eastern Piedmont Province near Baltimore) and Utah (eastern Uinta Mountains). ?? 1991 Springer-Verlag New York Inc.

  13. Theoretical and experimental analysis of the physics of water rockets

    NASA Astrophysics Data System (ADS)

    Barrio-Perotti, R.; Blanco-Marigorta, E.; Fernández-Francos, J.; Galdo-Vega, M.

    2010-09-01

    A simple rocket can be made using a plastic bottle filled with a volume of water and pressurized air. When opened, the air pressure pushes the water out of the bottle. This causes an increase in the bottle momentum so that it can be propelled to fairly long distances or heights. Water rockets are widely used as an educational activity, and several mathematical models have been proposed to investigate and predict their physics. However, the real equations that describe the physics of the rockets are so complicated that certain assumptions are usually made to obtain models that are easier to use. These models provide relatively good predictions but fail in describing the complex physics of the flow. This paper presents a detailed theoretical analysis of the physics of water rockets that concludes with the proposal of a physical model. The validity of the model is checked by a series of field tests. The tests showed maximum differences with predictions of about 6%. The proposed model is finally used to investigate the temporal evolution of some significant variables during the propulsion and flight of the rocket. The experience and procedure described in this paper can be proposed to graduate students and also at undergraduate level if certain simplifications are assumed in the general equations.

  14. Gender and Physics: A Theoretical Analysis.

    ERIC Educational Resources Information Center

    Rolin, Kristina

    2001-01-01

    Argues that objections raised by Koertge, Gross and Levitt, and Weinberg against feminist scholarship are unwarranted. The concept of gender, as it has been developed in feminist theory, is key to understanding why the first objection is misguided. Social analysis of scientific knowledge is key to understanding why the second and third objections…

  15. Active disturbance rejection control: methodology and theoretical analysis.

    PubMed

    Huang, Yi; Xue, Wenchao

    2014-07-01

    The methodology of ADRC and the progress of its theoretical analysis are reviewed in the paper. Several breakthroughs for control of nonlinear uncertain systems, made possible by ADRC, are discussed. The key in employing ADRC, which is to accurately determine the "total disturbance" that affects the output of the system, is illuminated. The latest results in theoretical analysis of the ADRC-based control systems are introduced.

  16. Optical pumping spectroscopy of Rb vapour with co-propagating laser beams: line identification by a simple theoretical model

    NASA Astrophysics Data System (ADS)

    Krmpot, Aleksandar J.; Rabasović, Mihailo D.; Jelenković, Branislav M.

    2010-07-01

    In this paper the saturation spectra of rubidium vapour at room temperature, obtained with overlapped co-propagating laser beams, were examined. Unlike the standard saturation spectroscopy, here the transmission of the pump laser beam was detected. The pump laser was locked to an atomic transition of the D2 line, while the probe laser frequency was scanned in a wide frequency range. The pump and probe beams had approximately the same intensities; thus the probe laser can saturate transitions and contribute to optical pumping. This, together with Doppler broadening, leads to rich pump transmission spectra, with many lines appearing due to the interaction of lasers with atoms in different velocity groups. The advantages of this method are well-resolved structures and appearance of spectral lines on a flat, Doppler-free background. Agreement between experimental and theoretical results shows the usefulness of this simple model, based on the rate equations, for identification of lines and determination of relative contribution to the observed line intensity from atoms with different velocities. Theoretical spectra are a useful tool for the calibration of experimental spectra obtained by a nonlinear dependence of the laser frequency on the voltage applied to the piezo used for the laser diode frequency scanning.

  17. On the complex relationship between energy expenditure and longevity: Reconciling the contradictory empirical results with a simple theoretical model.

    PubMed

    Hou, Chen; Amunugama, Kaushalya

    2015-07-01

    The relationship between energy expenditure and longevity has been a central theme in aging studies. Empirical studies have yielded controversial results, which cannot be reconciled by existing theories. In this paper, we present a simple theoretical model based on first principles of energy conservation and allometric scaling laws. The model takes into considerations the energy tradeoffs between life history traits and the efficiency of the energy utilization, and offers quantitative and qualitative explanations for a set of seemingly contradictory empirical results. We show that oxidative metabolism can affect cellular damage and longevity in different ways in animals with different life histories and under different experimental conditions. Qualitative data and the linearity between energy expenditure, cellular damage, and lifespan assumed in previous studies are not sufficient to understand the complexity of the relationships. Our model provides a theoretical framework for quantitative analyses and predictions. The model is supported by a variety of empirical studies, including studies on the cellular damage profile during ontogeny; the intra- and inter-specific correlations between body mass, metabolic rate, and lifespan; and the effects on lifespan of (1) diet restriction and genetic modification of growth hormone, (2) the cold and exercise stresses, and (3) manipulations of antioxidant.

  18. Empirical and theoretical analysis of complex systems

    NASA Astrophysics Data System (ADS)

    Zhao, Guannan

    structures evolve on a similar timescale to individual level transmission, we investigated the process of transmission through a model population comprising of social groups which follow simple dynamical rules for growth and break-up, and the profiles produced bear a striking resemblance to empirical data obtained from social, financial and biological systems. Finally, for better implementation of a widely accepted power law test algorithm, we have developed a fast testing procedure using parallel computation.

  19. A systematic theoretical study of harmonic vibrational frequencies: The ammonium ion NH4+ and other simple molecules

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yukio; Schaefer, Henry F.

    1980-09-01

    Analytic gradient techniques have been used to predict the harmonic vibrational frequencies of HCN, H2CO, H2O, CH4 and NH4+ at several levels of molecular electronic structure theory. Basis sets of double zeta, double zeta plus polarization, and extended plus polarization quality have been used in conjunction with self-consistent-field and configuration interaction methods. For the four spectroscopically characterized molecules, comparison with theory is particularly appropriate because experimental harmonic frequencies are available. For the 16 vibrational frequencies thus considered, the DZ SCF level of theory yields average errors of 166 cm-1 or 8.0%. The DZ+P SCF results are of comparable accuracy, differing on the average from experiment by 176 cm-1 or 8.3%. With the extended basis set, the comparable SCF frequency errors are only slightly less. The explicit incorporation of correlation effects qualitatively improves the agreement between theoretical and experimental harmonic vibrational frequencies. The DZ CI frequencies differ on the average by only 44 cm-1 or 2.0%. Perhaps surprisingly, the use of larger basis sets in conjunction with CI including all singly and doubly excited configurations leads to larger average errors in the vibrational frequencies. For example, the DZ+P CI frequencies have average errors of 80 cm-1 or 3.5%. Thus it seems clear that higher excitations (probably unlinked clusters especially) have a significant effect (order of 50 cm-1) on the theoretical prediction of polyatomic vibrational frequencies. The apparent discrepancy between the theoretical and experimental equilibrium geometry of CH4 is resolved here, and shown to have been a simple consequence of basis set incompleteness. Finally, the gas phase NH4+ equilibrium bond distance is predicted to be 1.022 Å, or 0.01-0.02 Å shorter than found by Ibers and Stevenson for NH4+ in crystalline NH4Cl and NH4F.

  20. Medial Cochlear Efferent Function: A Theoretical Analysis

    NASA Astrophysics Data System (ADS)

    Mountain, David C.

    2011-11-01

    Since the discovery of the cochlear efferent system, many hypotheses have been put forth for its function. These hypotheses for its function range from protecting the cochlea from over stimulation to improving the detection of sounds in noise. It is known that the medial efferent system innervates the outer hair cells and that stimulation of this system reduces basilar membrane and auditory nerve sensitivity which suggests that this system acts to decrease the gain of the cochlear amplifier. Here I present modeling results as well as analysis of published experimental data that suggest that the function of the medial efferent reflex is to decrease the cochlear amplifier gain by just the right amount so that the nonlinearity in the basilar membrane response lines up perfectly with the inner hair cell nonlinear transduction process to produce a hair cell receptor potential that is proportional to the logarithm of the sound pressure level.

  1. Development of Novel, Simple Multianalyte Sensors for Remote Environmental Analysis

    SciTech Connect

    Professor Sanford A. Asher

    2003-02-18

    Advancement of our polymerized crystalline colloidal array chemical sensing technology. They have dramatically advanced their polymerized crystalline colloidal array chemical sensing technology. They fabricated nonselective sensors for determining pH and ionic strength. They also developed selective sensors for glucose and organophosphorus mimics of nerve gas agents. They developed a trace sensor for cations in water which utilized a novel crosslinking sensing motif. In all of these cases they have been able to theoretically model their sensor response by extending hydrogel volume phase transition theory. They also developed transient sampling methods to allow their ion sensing methods to operate at high ionic strengths. They also developed a novel optrode to provide for simple sampling.

  2. Graph theoretical analysis of climate data

    NASA Astrophysics Data System (ADS)

    Zerenner, T.; Hense, A.

    2012-04-01

    Applying methods from graph and network theory to climatological data is a quite new approach and contains numerous difficulties. The atmosphere is a high dimensional and complex dynamical system which per se does not show a network-like structure. It does not consist of well-defined nodes and edges. Thus considering such a system as a network or graph inevitably involves radical simplifications and ambiguities. Nevertheless network analysis has provided useful results for different kinds of complex systems for example in biology or medical science (neural and gene interaction networks). The application of these methods on climate data provides interesting results as well. If the network construction is based on the correlation matrix of the underlying data, the resulting network structures show many well known patterns and characteristics of the atmospheric circulation (Tsonis et al. 2006, Donges et al. 2009). The interpretation of these network structures is yet questionable. Using Pearson Correlation for network construction does not allow to differ between direct and indirect dependencies. An edge does not necessarily represent a causal connection. An interpretation of these structures for instance concerning the stability of the climate system is therefore doubtful. Gene interaction networks for example are often constructed using partial correlations (Wu et al. 2003), which makes it possible to distinguish between direct and indirect dependencies. Although a high value of partial correlation does not guarantee causality it is a step in the direction of measuring causal dependencies. This approach is known as Gaussian Graphical Models, GGMs. For high dimensional datasets such as climate data partial correlations can be obtained by calculating the precision matrix, the inverse covariance matrix. Since the maximum likelihood estimates of covariance matrices of climate datasets are singular the precision matrices can only be estimated for example by using the

  3. Gender and Physics: a Theoretical Analysis

    NASA Astrophysics Data System (ADS)

    Rolin, Kristina

    This article argues that the objections raised by Koertge (1998), Gross and Levitt (1994), and Weinberg (1996) against feminist scholarship on gender and physics are unwarranted. The objections are that feminist science studies perpetuate gender stereotypes, are irrelevant to the content of physics, or promote epistemic relativism. In the first part of this article I argue that the concept of gender, as it has been developed in feminist theory, is a key to understanding why the first objection is misguided. Instead of reinforcing gender stereotypes, feminist science studies scholars can formulate empirically testable hypotheses regarding local and contested beliefs about gender. In the second part of this article I argue that a social analysis of scientific knowledge is a key to understanding why the second and the third objections are misguided. The concept of gender is relevant for understanding the social practice of physics, and the social practice of physics can be of epistemic importance. Instead of advancing epistemic relativism, feminist science studies scholars can make important contributions to a subfield of philosophy called social epistemology.

  4. Simple enrichment and analysis of plasma lysophosphatidic acids.

    PubMed

    Wang, Jialu; Sibrian-Vazquez, Martha; Escobedo, Jorge O; Lowry, Mark; Wang, Lei; Chu, Yu-Hsuan; Moore, Richard G; Strongin, Robert M

    2013-11-21

    A simple and highly efficient technique for the analysis of lysophosphatidic acid (LPA) subspecies in human plasma is described. The streamlined sample preparation protocol furnishes the five major LPA subspecies with excellent recoveries. Extensive analysis of the enriched sample reveals only trace levels of other phospholipids. This level of purity not only improves MS analyses, but enables HPLC post-column detection in the visible region with a commercially available fluorescent phospholipids probe. Human plasma samples from different donors were analyzed using the above method and validated by LC-ESI/MS/MS.

  5. Morphometric analysis of a fresh simple crater on the Moon.

    NASA Astrophysics Data System (ADS)

    Vivaldi, V.; Ninfo, A.; Massironi, M.; Martellato, E.; Cremonese, G.

    In this research we are proposing an innovative method to determine and quantify the morphology of a simple fresh impact crater. Linné is a well preserved impact crater of 2.2 km in diameter, located at 27.7oN 11.8oE, near the western edge of Mare Serenitatis on the Moon. The crater was photographed by the Lunar Orbiter and the Apollo space missions. Its particular morphology may place Linné as the most striking example of small fresh simple crater. Morphometric analysis, conducted on recent high resolution DTM from LROC (NASA), quantitatively confirmed the pristine morphology of the crater, revealing a clear inner layering which highlight a sequence of lava emplacement events.

  6. Theoretical and Experimental Investigation of Random Gust Loads Part I : Aerodynamic Transfer Function of a Simple Wing Configuration in Incompressible Flow

    NASA Technical Reports Server (NTRS)

    Hakkinen, Raimo J; Richardson, A S , Jr

    1957-01-01

    Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.

  7. Dissecting Situational Strength: Theoretical Analysis and Empirical Tests

    DTIC Science & Technology

    2012-09-01

    Technical Report 1315 Dissecting Situational Strength: Theoretical Analysis and Empirical Tests Reeshad S. Dalal George Mason ...George Mason University Charlie K. Brooks Georgia Institute of Technology September 2012 United States Army Research...MICHELLE SAMS, Ph.D. Director Research accomplished under contract for the Department of the Army George Mason University

  8. Path Analysis Tests of Theoretical Models of Children's Memory Performance

    ERIC Educational Resources Information Center

    DeMarie, Darlene; Miller, Patricia H.; Ferron, John; Cunningham, Walter R.

    2004-01-01

    Path analysis was used to test theoretical models of relations among variables known to predict differences in children's memory--strategies, capacity, and metamemory. Children in kindergarten to fourth grade (chronological ages 5 to 11) performed different memory tasks. Several strategies (i.e., sorting, clustering, rehearsal, and self-testing)…

  9. Theoretical Notes on the Sociological Analysis of School Reform Networks

    ERIC Educational Resources Information Center

    Ladwig, James G.

    2014-01-01

    Nearly two decades ago, Ladwig outlined the theoretical and methodological implications of Bourdieu's concept of the social field for sociological analyses of educational policy and school reform. The current analysis extends this work to consider the sociological import of one of the most ubiquitous forms of educational reform found around…

  10. Mode Deactivation Therapy (MDT) Family Therapy: A Theoretical Case Analysis

    ERIC Educational Resources Information Center

    Apsche, J. A.; Ward Bailey, S. R.

    2004-01-01

    This case study presents a theoretical analysis of implementing mode deactivation therapy (MDT) (Apsche & Ward Bailey, 2003) family therapy with a 13 year old Caucasian male. MDT is a form of cognitive behavioral therapy (CBT) that combines the balance of dialectical behavior therapy (DBT) (Linehan, 1993), the importance of perception from…

  11. Theoretical considerations and a simple method for measuring alkalinity and acidity in low-pH waters by gran titration

    USGS Publications Warehouse

    Barringer, J.L.; Johnsson, P.A.

    1996-01-01

    Titrations for alkalinity and acidity using the technique described by Gran (1952, Determination of the equivalence point in potentiometric titrations, Part II: The Analyst, v. 77, p. 661-671) have been employed in the analysis of low-pH natural waters. This report includes a synopsis of the theory and calculations associated with Gran's technique and presents a simple and inexpensive method for performing alkalinity and acidity determinations. However, potential sources of error introduced by the chemical character of some waters may limit the utility of Gran's technique. Therefore, the cost- and time-efficient method for performing alkalinity and acidity determinations described in this report is useful for exploring the suitability of Gran's technique in studies of water chemistry.

  12. A simple method for positional analysis of phosphatidylcholine.

    PubMed

    Kiełbowicz, Grzegorz; Gładkowski, Witold; Chojnacka, Anna; Wawrzeńczyk, Czesław

    2012-12-15

    Simple and fast method of positional analysis of fatty acid composition of phosphatidylcholine (PC) from egg-yolk and soy has been elaborated. The key step of the procedure was complete ethanolysis of PC catalyzed by sn-1,3 specific lipase from Mucor miehei (Lipozyme). 2-Acyl-lysophosphatidylcholine (2-acyl LPC), fatty acids ethyl esters (FAEEs) and free fatty acids (FAs) were formed in this process. No acyl migration was observed during the reaction. The products were entirely separated from the products mixture by simple extraction in water:hexane (2:3 v/v) system. The hexane fraction containing free FAs and FAEEs was treated with BF(3)/Et(2)O in ethanol to obtain only FAEEs. The analysis of FAEEs by GC gave the composition of the FAs in the sn-1 position of the PC. 2-Acyl LPC from water fraction after precipitation in cold (-20°C) acetone was converted into FAEEs and analyzed by gas chromatography (GC) to determine FAs composition in the sn-2 position of the PC.

  13. Theoretical analysis of subwavelength high contrast grating reflectors.

    PubMed

    Karagodsky, Vadim; Sedgwick, Forrest G; Chang-Hasnain, Connie J

    2010-08-02

    A simple analytic analysis of the ultra-high reflectivity feature of subwavelength dielectric gratings is developed. The phenomenon of ultra high reflectivity is explained to be a destructive interference effect between the two grating modes. Based on this phenomenon, a design algorithm for broadband grating mirrors is suggested.

  14. Game theoretic analysis of physical protection system design

    SciTech Connect

    Canion, B.; Schneider, E.; Bickel, E.; Hadlock, C.; Morton, D.

    2013-07-01

    The physical protection system (PPS) of a fictional small modular reactor (SMR) facility have been modeled as a platform for a game theoretic approach to security decision analysis. To demonstrate the game theoretic approach, a rational adversary with complete knowledge of the facility has been modeled attempting a sabotage attack. The adversary adjusts his decisions in response to investments made by the defender to enhance the security measures. This can lead to a conservative physical protection system design. Since defender upgrades were limited by a budget, cost benefit analysis may be conducted upon security upgrades. One approach to cost benefit analysis is the efficient frontier, which depicts the reduction in expected consequence per incremental increase in the security budget.

  15. A simple model of hysteresis behavior using spreadsheet analysis

    NASA Astrophysics Data System (ADS)

    Ehrmann, A.; Blachowicz, T.

    2015-01-01

    Hysteresis loops occur in many scientific and technical problems, especially as field dependent magnetization of ferromagnetic materials, but also as stress-strain-curves of materials measured by tensile tests including thermal effects, liquid-solid phase transitions, in cell biology or economics. While several mathematical models exist which aim to calculate hysteresis energies and other parameters, here we offer a simple model for a general hysteretic system, showing different hysteresis loops depending on the defined parameters. The calculation which is based on basic spreadsheet analysis plus an easy macro code can be used by students to understand how these systems work and how the parameters influence the reactions of the system on an external field. Importantly, in the step-by-step mode, each change of the system state, compared to the last step, becomes visible. The simple program can be developed further by several changes and additions, enabling the building of a tool which is capable of answering real physical questions in the broad field of magnetism as well as in other scientific areas, in which similar hysteresis loops occur.

  16. Simple analysis and design of annular ring microstrip antennas

    NASA Astrophysics Data System (ADS)

    El-Khamy, S. E.; El-Awadi, R. M.; El-Sharrawy, E.-B. A.

    1986-06-01

    A simple analysis of thin annular-ring microstrip antennas (AR-MSA), along with a design technique that yields the optimum ring dimensions which maximizes the radiation efficiency and the bandwidth, is presented in this paper. Using the cavity model, exact closed form solutions for the radiation fields are derived. The antenna fields distribution, resonance dimensions, radiation patterns, directivity, radiation conductance, quality factor and bandwidth are investigated for the different TMnm modes. AR-MSAs operated at the high order TMn2 modes are found to have better radiation properties and broader bandwidths than the corresponding disk-MSAs. A design table for the optimum ring dimensions for different types of the dielectric substrate material is also given in the paper.

  17. Cost analysis and outcomes of simple elbow dislocations

    PubMed Central

    Panteli, Michalis; Pountos, Ippokratis; Kanakaris, Nikolaos K; Tosounidis, Theodoros H; Giannoudis, Peter V

    2015-01-01

    AIM: To evaluate the management, clinical outcome and cost implications of three different treatment regimes for simple elbow dislocations. METHODS: Following institutional board approval, we performed a retrospective review of all consecutive patients treated for simple elbow dislocations in a Level I trauma centre between January 2008 and December 2010. Based on the length of elbow immobilisation (LOI), patients were divided in three groups (Group I, < 2 wk; Group II, 2-3 wk; and Group III, > 3 wk). Outcome was considered satisfactory when a patient could achieve a pain-free range of motion ≥ 100° (from 30° to 130°). The associated direct medical costs for the treatment of each patient were then calculated and analysed. RESULTS: We identified 80 patients who met the inclusion criteria. Due to loss to follow up, 13 patients were excluded from further analysis, leaving 67 patients for the final analysis. The mean LOI was 14 d (median 15 d; range 3-43 d) with a mean duration of hospital engagement of 67 d (median 57 d; range 10-351 d). Group III (prolonged immobilisation) had a statistically significant worse outcome in comparison to Group I and II (P = 0.04 and P = 0.01 respectively); however, there was no significant difference in the outcome between groups I and II (P = 0.30). No statistically significant difference in the direct medical costs between the groups was identified. CONCLUSION: The length of elbow immobilization doesn’t influence the medical cost; however immobilisation longer than three weeks is associated with persistent stiffness and a less satisfactory clinical outcome. PMID:26301180

  18. Theoretical Analysis of Heuristic Search Methods for Online POMDPs.

    PubMed

    Ross, Stéphane; Pineau, Joelle; Chaib-Draa, Brahim

    2008-01-01

    Planning in partially observable environments remains a challenging problem, despite significant recent advances in offline approximation techniques. A few online methods have also been proposed recently, and proven to be remarkably scalable, but without the theoretical guarantees of their offline counterparts. Thus it seems natural to try to unify offline and online techniques, preserving the theoretical properties of the former, and exploiting the scalability of the latter. In this paper, we provide theoretical guarantees on an anytime algorithm for POMDPs which aims to reduce the error made by approximate offline value iteration algorithms through the use of an efficient online searching procedure. The algorithm uses search heuristics based on an error analysis of lookahead search, to guide the online search towards reachable beliefs with the most potential to reduce error. We provide a general theorem showing that these search heuristics are admissible, and lead to complete and ε-optimal algorithms. This is, to the best of our knowledge, the strongest theoretical result available for online POMDP solution methods. We also provide empirical evidence showing that our approach is also practical, and can find (provably) near-optimal solutions in reasonable time.

  19. Theoretical structure of adolescent alienation: a multigroup confirmatory factor analysis.

    PubMed

    Lacourse, Eric; Villeneuve, Martine; Claes, Michel

    2003-01-01

    This study examined the construct validity of adolescent alienation using second-order confirmatory factor analysis of the five dimensions conceptualized by Seeman (1959). Analysis was based on data from 275 high school students aged 14 to 18. The hypothesized multidimensionality of the construct was confirmed for both boys and girls using a second-order factor labeled alienation. Central dimensions of alienation as a latent construct were self-estrangement and powerlessness. Social isolation, meaninglessness, and especially normlessness were poorly explained by the second-order factor, suggesting that these dimensions entail enough specificity to be considered separately. A different theoretical model relating these dimensions is suggested and discussed.

  20. Python for information theoretic analysis of neural data.

    PubMed

    Ince, Robin A A; Petersen, Rasmus S; Swan, Daniel C; Panzeri, Stefano

    2009-01-01

    Information theory, the mathematical theory of communication in the presence of noise, is playing an increasingly important role in modern quantitative neuroscience. It makes it possible to treat neural systems as stochastic communication channels and gain valuable, quantitative insights into their sensory coding function. These techniques provide results on how neurons encode stimuli in a way which is independent of any specific assumptions on which part of the neuronal response is signal and which is noise, and they can be usefully applied even to highly non-linear systems where traditional techniques fail. In this article, we describe our work and experiences using Python for information theoretic analysis. We outline some of the algorithmic, statistical and numerical challenges in the computation of information theoretic quantities from neural data. In particular, we consider the problems arising from limited sampling bias and from calculation of maximum entropy distributions in the presence of constraints representing the effects of different orders of interaction in the system. We explain how and why using Python has allowed us to significantly improve the speed and domain of applicability of the information theoretic algorithms, allowing analysis of data sets characterized by larger numbers of variables. We also discuss how our use of Python is facilitating integration with collaborative databases and centralised computational resources.

  1. A Theoretical Analysis of Why Hybrid Ensembles Work

    PubMed Central

    2017-01-01

    Inspired by the group decision making process, ensembles or combinations of classifiers have been found favorable in a wide variety of application domains. Some researchers propose to use the mixture of two different types of classification algorithms to create a hybrid ensemble. Why does such an ensemble work? The question remains. Following the concept of diversity, which is one of the fundamental elements of the success of ensembles, we conduct a theoretical analysis of why hybrid ensembles work, connecting using different algorithms to accuracy gain. We also conduct experiments on classification performance of hybrid ensembles of classifiers created by decision tree and naïve Bayes classification algorithms, each of which is a top data mining algorithm and often used to create non-hybrid ensembles. Therefore, through this paper, we provide a complement to the theoretical foundation of creating and using hybrid ensembles. PMID:28255296

  2. Global analysis of a "simple" proteome : methanococcus jannaschii.

    SciTech Connect

    Giometti, C. S.; Reich, C.; Tollaksen, S.; Babnigg, G.; Lim, H.; Zhu, W.; Olsen, G.; Biosciences Division; Univ. of Illinois; Scripps Inst.

    2002-12-25

    The completed genome of Methanococcus jannaschii, including the main chromosome and two extra-chromosomal elements, predicts a proteome comprised of 1783 proteins. How many of those proteins are expressed at any given time and the relative abundance of the expressed proteins, however, cannot be predicted solely from the genome sequence. Two-dimensional gel electrophoresis coupled with peptide mass spectrometry is being used to identify the proteins expressed by M. jannaschii cells grown under different conditions as part of an effort to correlate protein expression with regulatory mechanisms. Here we describe the identification of 170 of the most abundant proteins found in total lysates of M. jannaschii grown under optimal fermentation conditions. To optimize the number of proteins detected, two different protein specific stains (Coomassie Blue R250 or silver nitrate) and two different first dimension separation methods (isoelectric focusing or nonequilibrium pH gradient electrophoresis) were used. Thirty-two percent of the proteins identified are annotated as hypothetical (21% conserved hypothetical and 11% hypothetical), 21% are enzymes involved in energy metabolism, 12% are proteins required for protein synthesis, and the remainder include proteins necessary for intermediary metabolism, cell division, and cell structure. Evidence of post-translational modification of numerous M. jannaschii proteins has been found, as well as indications of incomplete dissociation of protein-protein complexes. These results demonstrate the complexity of proteome analysis even when dealing with a relatively simple genome.

  3. Global analysis of a 'simple' proteome : methanoccus jannaschii.

    SciTech Connect

    Giometti, C. S.; Reich, C.; Tollaksen, S.; Babnigg, G.; Lim, H.; Zhu, W.; Yates, J., III; Olsen, G.; Biosciences Division; Univ. of Illinois; The Scripps Inst.

    2002-12-25

    The completed genome of Methanococcus jannaschii, including the main chromosome and two extra-chromosomal elements, predicts a proteome comprised of 1783 proteins. How many of those proteins are expressed at any given time and the relative abundance of the expressed proteins, however, cannot be predicted solely from the genome sequence. Two-dimensional gel electrophoresis coupled with peptide mass spectrometry is being used to identify the proteins expressed by M. jannaschii cells grown under different conditions as part of an effort to correlate protein expression with regulatory mechanisms. Here we describe the identification of 170 of the most abundant proteins found in total lysates of M. jannaschii grown under optimal fermentation conditions. To optimize the number of proteins detected, two different protein specific stains (Coomassie Blue R250 or silver nitrate) and two different first dimension separation methods (isoelectric focusing or nonequilibrium pH gradient electrophoresis) were used. Thirty-two percent of the proteins identified are annotated as hypothetical (21% conserved hypothetical and 11% hypothetical), 21% are enzymes involved in energy metabolism, 12% are proteins required for protein synthesis, and the remainder include proteins necessary for intermediary metabolism, cell division, and cell structure. Evidence of post-translational modification of numerous M. jannaschii proteins has been found, as well as indications of incomplete dissociation of protein-protein complexes. These results demonstrate the complexity of proteome analysis even when dealing with a relatively simple genome.

  4. Evolution Analysis of Simple Sequence Repeats in Plant Genome.

    PubMed

    Qin, Zhen; Wang, Yanping; Wang, Qingmei; Li, Aixian; Hou, Fuyun; Zhang, Liming

    2015-01-01

    Simple sequence repeats (SSRs) are widespread units on genome sequences, and play many important roles in plants. In order to reveal the evolution of plant genomes, we investigated the evolutionary regularities of SSRs during the evolution of plant species and the plant kingdom by analysis of twelve sequenced plant genome sequences. First, in the twelve studied plant genomes, the main SSRs were those which contain repeats of 1-3 nucleotides combination. Second, in mononucleotide SSRs, the A/T percentage gradually increased along with the evolution of plants (except for P. patens). With the increase of SSRs repeat number the percentage of A/T in C. reinhardtii had no significant change, while the percentage of A/T in terrestrial plants species gradually declined. Third, in dinucleotide SSRs, the percentage of AT/TA increased along with the evolution of plant kingdom and the repeat number increased in terrestrial plants species. This trend was more obvious in dicotyledon than monocotyledon. The percentage of CG/GC showed the opposite pattern to the AT/TA. Forth, in trinucleotide SSRs, the percentages of combinations including two or three A/T were in a rising trend along with the evolution of plant kingdom; meanwhile with the increase of SSRs repeat number in plants species, different species chose different combinations as dominant SSRs. SSRs in C. reinhardtii, P. patens, Z. mays and A. thaliana showed their specific patterns related to evolutionary position or specific changes of genome sequences. The results showed that, SSRs not only had the general pattern in the evolution of plant kingdom, but also were associated with the evolution of the specific genome sequence. The study of the evolutionary regularities of SSRs provided new insights for the analysis of the plant genome evolution.

  5. Theoretical analysis of transcription process with polymerase stalling

    NASA Astrophysics Data System (ADS)

    Li, Jingwei; Zhang, Yunxin

    2015-05-01

    Experimental evidence shows that in gene transcription RNA polymerase has the possibility to be stalled at a certain position of the transcription template. This may be due to the template damage or protein barriers. Once stalled, polymerase may backtrack along the template to the previous nucleotide to wait for the repair of the damaged site, simply bypass the barrier or damaged site and consequently synthesize an incorrect messenger RNA, or degrade and detach from the template. Thus, the effective transcription rate (the rate to synthesize correct product mRNA) and the transcription effectiveness (the ratio of the effective transcription rate to the effective transcription initiation rate) are both influenced by polymerase stalling events. So far, no theoretical model has been given to discuss the gene transcription process including polymerase stalling. In this study, based on the totally asymmetric simple exclusion process, the transcription process including polymerase stalling is analyzed theoretically. The dependence of the effective transcription rate, effective transcription initiation rate, and transcription effectiveness on the transcription initiation rate, termination rate, as well as the backtracking rate, bypass rate, and detachment (degradation) rate when stalling, are discussed in detail. The results showed that backtracking restart after polymerase stalling is an ideal mechanism to increase both the effective transcription rate and the transcription effectiveness. Without backtracking, detachment of stalled polymerase can also help to increase the effective transcription rate and transcription effectiveness. Generally, the increase of the bypass rate of the stalled polymerase will lead to the decrease of the effective transcription rate and transcription effectiveness. However, when both detachment rate and backtracking rate of the stalled polymerase vanish, the effective transcription rate may also be increased by the bypass mechanism.

  6. Theoretical analysis of transcription process with polymerase stalling.

    PubMed

    Li, Jingwei; Zhang, Yunxin

    2015-05-01

    Experimental evidence shows that in gene transcription RNA polymerase has the possibility to be stalled at a certain position of the transcription template. This may be due to the template damage or protein barriers. Once stalled, polymerase may backtrack along the template to the previous nucleotide to wait for the repair of the damaged site, simply bypass the barrier or damaged site and consequently synthesize an incorrect messenger RNA, or degrade and detach from the template. Thus, the effective transcription rate (the rate to synthesize correct product mRNA) and the transcription effectiveness (the ratio of the effective transcription rate to the effective transcription initiation rate) are both influenced by polymerase stalling events. So far, no theoretical model has been given to discuss the gene transcription process including polymerase stalling. In this study, based on the totally asymmetric simple exclusion process, the transcription process including polymerase stalling is analyzed theoretically. The dependence of the effective transcription rate, effective transcription initiation rate, and transcription effectiveness on the transcription initiation rate, termination rate, as well as the backtracking rate, bypass rate, and detachment (degradation) rate when stalling, are discussed in detail. The results showed that backtracking restart after polymerase stalling is an ideal mechanism to increase both the effective transcription rate and the transcription effectiveness. Without backtracking, detachment of stalled polymerase can also help to increase the effective transcription rate and transcription effectiveness. Generally, the increase of the bypass rate of the stalled polymerase will lead to the decrease of the effective transcription rate and transcription effectiveness. However, when both detachment rate and backtracking rate of the stalled polymerase vanish, the effective transcription rate may also be increased by the bypass mechanism.

  7. Tetrad Analysis: A Practical Demonstration Using Simple Models.

    ERIC Educational Resources Information Center

    Gow, Mary M.; Nicholl, Desmond S. T.

    1988-01-01

    Uses simple models to illustrate the principles of this genetic method of mapping gene loci. Stresses that this system enables a practical approach to be used with students who experience difficulty in understanding the concepts involved. (CW)

  8. Simple models for quorum sensing: Nonlinear dynamical analysis

    NASA Astrophysics Data System (ADS)

    Chiang, Wei-Yin; Li, Yue-Xian; Lai, Pik-Yin

    2011-10-01

    Quorum sensing refers to the change in the cooperative behavior of a collection of elements in response to the change in their population size or density. This behavior can be observed in chemical and biological systems. These elements or cells are coupled via chemicals in the surrounding environment. Here we focus on the change of dynamical behavior, in particular from quiescent to oscillatory, as the cell population changes. For instance, the silent behavior of the elements can become oscillatory as the system concentration or population increases. In this work, two simple models are constructed that can produce the essential representative properties in quorum sensing. The first is an excitable or oscillatory phase model, which is probably the simplest model one can construct to describe quorum sensing. Using the mean-field approximation, the parameter regime for quorum sensing behavior can be identified, and analytical results for the detailed dynamical properties, including the phase diagrams, are obtained and verified numerically. The second model consists of FitzHugh-Nagumo elements coupled to the signaling chemicals in the environment. Nonlinear dynamical analysis of this mean-field model exhibits rich dynamical behaviors, such as infinite period bifurcation, supercritical Hopf, fold bifurcation, and subcritical Hopf bifurcations as the population parameter changes for different coupling strengths. Analytical result is obtained for the Hopf bifurcation phase boundary. Furthermore, two elements coupled via the environment and their synchronization behavior for these two models are also investigated. For both models, it is found that the onset of oscillations is accompanied by the synchronized dynamics of the two elements. Possible applications and extension of these models are also discussed.

  9. Isolation of exosomes by differential centrifugation: Theoretical analysis of a commonly used protocol

    PubMed Central

    Livshts, Mikhail A.; Khomyakova, Elena; Evtushenko, Evgeniy G.; Lazarev, Vassili N.; Kulemin, Nikolay A.; Semina, Svetlana E.; Generozov, Edward V.; Govorun, Vadim M.

    2015-01-01

    Exosomes, small (40–100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for “fixed-angle” rotors. For both types of rotors – “swinging bucket” and “fixed-angle” – we express the theoretically expected proportion of pelleted vesicles of a given size and the “cut-off” size of completely sedimented vesicles as dependent on the centrifugation force and duration and the sedimentation path-lengths. The proper centrifugation conditions can be selected using relatively simple theoretical estimates of the “cut-off” sizes of vesicles. Experimental verification on exosomes isolated from HT29 cell culture supernatant confirmed the main theoretical statements. Measured by the nanoparticle tracking analysis (NTA) technique, the concentration and size distribution of the vesicles after centrifugation agree with those theoretically expected. To simplify this “cut-off”-size-based adjustment of centrifugation protocol for any rotor, we developed a web-calculator. PMID:26616523

  10. Isolation of exosomes by differential centrifugation: Theoretical analysis of a commonly used protocol

    NASA Astrophysics Data System (ADS)

    Livshts, Mikhail A.; Khomyakova, Elena; Evtushenko, Evgeniy G.; Lazarev, Vassili N.; Kulemin, Nikolay A.; Semina, Svetlana E.; Generozov, Edward V.; Govorun, Vadim M.

    2015-11-01

    Exosomes, small (40-100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for “fixed-angle” rotors. For both types of rotors - “swinging bucket” and “fixed-angle” - we express the theoretically expected proportion of pelleted vesicles of a given size and the “cut-off” size of completely sedimented vesicles as dependent on the centrifugation force and duration and the sedimentation path-lengths. The proper centrifugation conditions can be selected using relatively simple theoretical estimates of the “cut-off” sizes of vesicles. Experimental verification on exosomes isolated from HT29 cell culture supernatant confirmed the main theoretical statements. Measured by the nanoparticle tracking analysis (NTA) technique, the concentration and size distribution of the vesicles after centrifugation agree with those theoretically expected. To simplify this “cut-off”-size-based adjustment of centrifugation protocol for any rotor, we developed a web-calculator.

  11. Theoretical analysis of dynamic processes for interacting molecular motors

    NASA Astrophysics Data System (ADS)

    Teimouri, Hamid; Kolomeisky, Anatoly B.; Mehrabiani, Kareem

    2015-02-01

    Biological transport is supported by the collective dynamics of enzymatic molecules that are called motor proteins or molecular motors. Experiments suggest that motor proteins interact locally via short-range potentials. We investigate the fundamental role of these interactions by carrying out an analysis of a new class of totally asymmetric exclusion processes, in which interactions are accounted for in a thermodynamically consistent fashion. This allows us to explicitly connect microscopic features of motor proteins with their collective dynamic properties. A theoretical analysis that combines various mean-field calculations and computer simulations suggests that the dynamic properties of molecular motors strongly depend on the interactions, and that the correlations are stronger for interacting motor proteins. Surprisingly, it is found that there is an optimal strength of interactions (weak repulsion) that leads to a maximal particle flux. It is also argued that molecular motor transport is more sensitive to attractive interactions. Applications of these results for kinesin motor proteins are discussed.

  12. Analysis of the theoretical bias in dark matter direct detection

    SciTech Connect

    Catena, Riccardo

    2014-09-01

    Fitting the model ''A'' to dark matter direct detection data, when the model that underlies the data is ''B'', introduces a theoretical bias in the fit. We perform a quantitative study of the theoretical bias in dark matter direct detection, with a focus on assumptions regarding the dark matter interactions, and velocity distribution. We address this problem within the effective theory of isoscalar dark matter-nucleon interactions mediated by a heavy spin-1 or spin-0 particle. We analyze 24 benchmark points in the parameter space of the theory, using frequentist and Bayesian statistical methods. First, we simulate the data of future direct detection experiments assuming a momentum/velocity dependent dark matter-nucleon interaction, and an anisotropic dark matter velocity distribution. Then, we fit a constant scattering cross section, and an isotropic Maxwell-Boltzmann velocity distribution to the simulated data, thereby introducing a bias in the analysis. The best fit values of the dark matter particle mass differ from their benchmark values up to 2 standard deviations. The best fit values of the dark matter-nucleon coupling constant differ from their benchmark values up to several standard deviations. We conclude that common assumptions in dark matter direct detection are a source of potentially significant bias.

  13. A Model and Simple Iterative Algorithm for Redundancy Analysis.

    ERIC Educational Resources Information Center

    Fornell, Claes; And Others

    1988-01-01

    This paper shows that redundancy maximization with J. K. Johansson's extension can be accomplished via a simple iterative algorithm based on H. Wold's Partial Least Squares. The model and the iterative algorithm for the least squares approach to redundancy maximization are presented. (TJH)

  14. Reversal of Emergent Simple Discrimination in Children: A Component Analysis.

    ERIC Educational Resources Information Center

    Smeets, Paul M.; And Others

    1995-01-01

    Examined reversal of emergent simple discriminations through stimulus contiguity. In experiment one, Baseline and Reversal phases were positive for most children. Experiments two through four examined protocol aspects that possibly contributed to successful reversal of the form discrimination; found that reversed discrimination usually was a…

  15. A theoretical analysis of vacuum arc thruster performance

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Sekerak, Mike; Ziemer, John K.; Schein, Jochen; Qi, Niansheng; Binder, Robert; Anders, Andre

    2001-01-01

    In vacuum arc discharges the current is conducted through vapor evaporated from the cathode surface. In these devices very dense, highly ionized plasmas can be created from any metallic or conducting solid used as the cathode. This paper describes theoretical models of performance for several thruster configurations which use vacuum arc plasma sources. This analysis suggests that thrusters using vacuum arc sources can be operated efficiently with a range of propellant options that gives great flexibility in specific impulse. In addition, the efficiency of plasma production in these devices appears to be largely independent of scale because the metal vapor is ionized within a few microns of the cathode electron emission sites, so this approach is well-suited for micropropulsion.

  16. Theoretical Analysis of Dynamic Processes for Interacting Molecular Motors.

    PubMed

    Teimouri, Hamid; Kolomeisky, Anatoly B; Mehrabiani, Kareem

    2015-02-13

    Biological transport is supported by collective dynamics of enzymatic molecules that are called motor proteins or molecular motors. Experiments suggest that motor proteins interact locally via short-range potentials. We investigate the fundamental role of these interactions by analyzing a new class of totally asymmetric exclusion processes where interactions are accounted for in a thermodynamically consistent fashion. It allows us to connect explicitly microscopic features of motor proteins with their collective dynamic properties. Theoretical analysis that combines various mean-field calculations and computer simulations suggests that dynamic properties of molecular motors strongly depend on interactions, and correlations are stronger for interacting motor proteins. Surprisingly, it is found that there is an optimal strength of interactions (weak repulsion) that leads to a maximal particle flux. It is also argued that molecular motors transport is more sensitive to attractive interactions. Applications of these results for kinesin motor proteins are discussed.

  17. Two-dimensional electronic spectroscopy using incoherent light: theoretical analysis.

    PubMed

    Turner, Daniel B; Howey, Dylan J; Sutor, Erika J; Hendrickson, Rebecca A; Gealy, M W; Ulness, Darin J

    2013-07-25

    Electronic energy transfer in photosynthesis occurs over a range of time scales and under a variety of intermolecular coupling conditions. Recent work has shown that electronic coupling between chromophores can lead to coherent oscillations in two-dimensional electronic spectroscopy measurements of pigment-protein complexes measured with femtosecond laser pulses. A persistent issue in the field is to reconcile the results of measurements performed using femtosecond laser pulses with physiological illumination conditions. Noisy-light spectroscopy can begin to address this question. In this work we present the theoretical analysis of incoherent two-dimensional electronic spectroscopy, I((4)) 2D ES. Simulations reveal diagonal peaks, cross peaks, and coherent oscillations similar to those observed in femtosecond two-dimensional electronic spectroscopy experiments. The results also expose fundamental differences between the femtosecond-pulse and noisy-light techniques; the differences lead to new challenges and new opportunities.

  18. Self-mixing grating interferometer: theoretical analysis and experimental observations

    NASA Astrophysics Data System (ADS)

    Guo, Dongmei; Wang, Ming; Hao, Hui

    2016-08-01

    By combining self-mixing interferometer (SMI) and grating interferometer (GI), a self-mixing grating interferometer (SMGI) is proposed in this paper. Self-mixing interference occurs when light emitted from a laser diode is diffracted by the doublediffraction system and re-enters the laser active cavity, thus generating a modulation of both the amplitude and the frequency of the lasing field. Theoretical analysis and experimental observations show that the SMGI has the same phase sensitivity as that of the conventional GI and the direction of the phase movement can be obtained from inclination of the interference signal. Compared with the traditional SMI, the phase change of interference signal in SMGI is independent of laser wavelength, providing better immunity against environmental disturbances such as temperature, pressure, and humidity variation. Compared with the traditional GI, the SMGI provides a potential displacement sensor with directional discrimination and quite compact configuration.

  19. Game-theoretic equilibrium analysis applications to deregulated electricity markets

    NASA Astrophysics Data System (ADS)

    Joung, Manho

    This dissertation examines game-theoretic equilibrium analysis applications to deregulated electricity markets. In particular, three specific applications are discussed: analyzing the competitive effects of ownership of financial transmission rights, developing a dynamic game model considering the ramp rate constraints of generators, and analyzing strategic behavior in electricity capacity markets. In the financial transmission right application, an investigation is made of how generators' ownership of financial transmission rights may influence the effects of the transmission lines on competition. In the second application, the ramp rate constraints of generators are explicitly modeled using a dynamic game framework, and the equilibrium is characterized as the Markov perfect equilibrium. Finally, the strategic behavior of market participants in electricity capacity markets is analyzed and it is shown that the market participants may exaggerate their available capacity in a Nash equilibrium. It is also shown that the more conservative the independent system operator's capacity procurement, the higher the risk of exaggerated capacity offers.

  20. Theoretical analysis of tsunami generation by pyroclastic flows

    USGS Publications Warehouse

    Watts, P.; Waythomas, C.F.

    2003-01-01

    Pyroclastic flows are a common product of explosive volcanism and have the potential to initiate tsunamis whenever thick, dense flows encounter bodies of water. We evaluate the process of tsunami generation by pyroclastic flow by decomposing the pyroclastic flow into two components, the dense underflow portion, which we term the pyroclastic debris flow, and the plume, which includes the surge and coignimbrite ash cloud parts of the flow. We consider five possible wave generation mechanisms. These mechanisms consist of steam explosion, pyroclastic debris flow, plume pressure, plume shear, and pressure impulse wave generation. Our theoretical analysis of tsunami generation by these mechanisms provides an estimate of tsunami features such as a characteristic wave amplitude and wavelength. We find that in most situations, tsunami generation is dominated by the pyroclastic debris flow component of a pyroclastic flow. This work presents information sufficient to construct tsunami sources for an arbitrary pyroclastic flow interacting with most bodies of water. Copyright 2003 by the American Geophysical Union.

  1. Theoretical analysis of sound transmission loss through graphene sheets

    SciTech Connect

    Natsuki, Toshiaki; Ni, Qing-Qing

    2014-11-17

    We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials.

  2. How Do Pseudocapacitors Store Energy? Theoretical Analysis and Experimental Illustration.

    PubMed

    Costentin, Cyrille; Porter, Thomas R; Savéant, Jean-Michel

    2017-03-15

    Batteries and electrochemical double layer charging capacitors are two classical means of storing electrical energy. These two types of charge storage can be unambiguously distinguished from one another by the shape and scan-rate dependence of their cyclic voltammetric (CV) current-potential responses. The former shows peak-shaped current-potential responses, proportional to the scan rate v or to v(1/2), whereas the latter displays a quasi-rectangular response proportional to the scan rate. On the contrary, the notion of pseudocapacitance, popularized in the 1980s and 1990s for metal oxide systems, has been used to describe a charge storage process that is faradaic in nature yet displays capacitive CV signatures. It has been speculated that a quasi-rectangular CV response resembling that of a truly capacitive response arises from a series of faradaic redox couples with a distribution of potentials, yet this idea has never been justified theoretically. We address this problem by first showing theoretically that this distribution-of-potentials approach is closely equivalent to the more physically meaningful consideration of concentration-dependent activity coefficients resulting from interactions between reactants. The result of the ensuing analysis is that, in either case, the CV responses never yield a quasi-rectangular response ∝ ν, identical to that of double layer charging. Instead, broadened peak-shaped responses are obtained. It follows that whenever a quasi-rectangular CV response proportional to scan rate is observed, such reputed pseudocapacitive behaviors should in fact be ascribed to truly capacitive double layer charging. We compare these results qualitatively with pseudocapacitor reports taken from the literature, including the classic RuO2 and MnO2 examples, and we present a quantitative analysis with phosphate cobalt oxide films. Our conclusions do not invalidate the numerous experimental studies carried out under the pseudocapacitance banner but

  3. Motility of a model bristle-bot: A theoretical analysis

    NASA Astrophysics Data System (ADS)

    Cicconofri, Giancarlo; DeSimone, Antonio

    2015-11-01

    Bristle-bots are legged robots that can be easily made out of a toothbrush head and a small vibrating engine. Despite their simple appearance, the mechanism enabling them to propel themselves by exploiting friction with the substrate is far from trivial. Numerical experiments on a model bristle-bot have been able to reproduce such a mechanism revealing, in addition, the ability to switch direction of motion by varying the vibration frequency. This paper provides a detailed account of these phenomena through a fully analytical treatment of the model. The equations of motion are solved through an expansion in terms of a properly chosen small parameter. The convergence of the expansion is rigorously proven. In addition, the analysis delivers formulas for the average velocity of the robot and for the frequency at which the direction switch takes place. A quantitative description of the mechanism for the friction modulation underlying the motility of the bristle-bot is also provided.

  4. Theoretical performance analysis of multislice channelized Hotelling observers

    NASA Astrophysics Data System (ADS)

    Goossens, Bart; Platiša, Ljiljana; Philips, Wilfried

    2012-02-01

    Quality assessment of 3D medical images is becoming increasingly important, because of clinical practice rapidly moving in the direction of volumetric imaging. In a recent publication, three multi-slice channelized Hotelling observer (msCHO) models are presented for the task of detecting 3D signals in multi-slice images, where each multi-slice image is inspected in a so called stack-browsing mode. The observer models are based on the assumption that humans observe multi-slice images in a simple two stage process, and each of the models implement this principle in a different way. In this paper, we investigate the theoretical performance, in terms of detection signal-to-noise-ratio (SNR) of msCHO models, for the task of detecting a separable signal in a Gaussian background with separable covariance matrix. We find that, despite the differences in architecture of the three models, they all have the same asymptotical performance in this task (i.e., when the number of training images tends to infinity). On the other hand, when backgrounds with nonseparable covariance matrices are considered, the third model, msCHOc, is expected to perform slightly better than the other msCHO models (msCHOa and msCHOb), but only when sufficient training images are provided. These findings suggest that the choice between the msCHO models mainly depends on the experiment setup (e.g., the number of available training samples), while the relation to human observers depends on the particular choice of the "temporal" channels that the msCHO models use.

  5. Infrared and theoretical calculations in 2-halocycloheptanones conformational analysis.

    PubMed

    Rozada, Thiago C; Gauze, Gisele F; Favaro, Denize C; Rittner, Roberto; Basso, Ernani A

    2012-08-01

    2-Halocycloheptanones (Halo=F, Cl, Br and I) were synthesized and their conformational analysis was performed through infrared spectroscopy data. The corresponding conformers geometries and energies were obtained by theoretical calculations at B3LYP/aug-cc-pVDZ level of theory in the isolated state and in solution. It was observed, by both approaches, that the conformational preferences were very sensitive to the solvent polarity, since its increase led to an increase in the population of the more polar conformer. An analysis of these conformational equilibria showed they suffer also the influence of stereoelectronic effects, like hyperconjugation and steric effects. These results were interpreted using natural bond orbital (NBO) analysis, which indicated that the electronic delocalization to the orbital π*(C=O) is directly involved in the stability increase of conformers I and II. The relative effect of the period of the halogen can also be noted, with changes in the conformational preferences and in the energies involved in the interactions of NBO.

  6. A Model and Simple Iterative Algorithm For Redundancy Analysis.

    PubMed

    Fornell, C; Barclay, D W; Rhee, B D

    1988-07-01

    Stewart and Love proposed redundancy as an index for measuring the amount of shared variance between two sets of variables. van den Wollenberg presented a method for maximizing redundancy. Johansson extended the approach to include derivation of optimal Y-variates, given the X-variates. This paper shows that redundancy maximization with Johansson's extension can be accomplished via a simple iterative algorithm based on Wold's Partial Least Squares.

  7. Designing novel Sn-Bi, Si-C and Ge-C nanostructures, using simple theoretical chemical similarities

    PubMed Central

    2011-01-01

    A framework of simple, transparent and powerful concepts is presented which is based on isoelectronic (or isovalent) principles, analogies, regularities and similarities. These analogies could be considered as conceptual extensions of the periodical table of the elements, assuming that two atoms or molecules having the same number of valence electrons would be expected to have similar or homologous properties. In addition, such similar moieties should be able, in principle, to replace each other in more complex structures and nanocomposites. This is only partly true and only occurs under certain conditions which are investigated and reviewed here. When successful, these concepts are very powerful and transparent, leading to a large variety of nanomaterials based on Si and other group 14 elements, similar to well known and well studied analogous materials based on boron and carbon. Such nanomaterias designed in silico include, among many others, Si-C, Sn-Bi, Si-C and Ge-C clusters, rings, nanowheels, nanorodes, nanocages and multidecker sandwiches, as well as silicon planar rings and fullerenes similar to the analogous sp2 bonding carbon structures. It is shown that this pedagogically simple and transparent framework can lead to an endless variety of novel and functional nanomaterials with important potential applications in nanotechnology, nanomedicine and nanobiology. Some of the so called predicted structures have been already synthesized, not necessarily with the same rational and motivation. Finally, it is anticipated that such powerful and transparent rules and analogies, in addition to their predictive power, could also lead to far-reaching interpretations and a deeper understanding of already known results and information. PMID:21711875

  8. Theoretical analysis of the state of balance in bipedal walking.

    PubMed

    Firmani, Flavio; Park, Edward J

    2013-04-01

    This paper presents a theoretical analysis based on classic mechanical principles of balance of forces in bipedal walking. Theories on the state of balance have been proposed in the area of humanoid robotics and although the laws of classical mechanics are equivalent to both humans and humanoid robots, the resulting motion obtained with these theories is unnatural when compared to normal human gait. Humanoid robots are commonly controlled using the zero moment point (ZMP) with the condition that the ZMP cannot exit the foot-support area. This condition is derived from a physical model in which the biped must always walk under dynamically balanced conditions, making the centre of pressure (CoP) and the ZMP always coincident. On the contrary, humans follow a different strategy characterized by a 'controlled fall' at the end of the swing phase. In this paper, we present a thorough theoretical analysis of the state of balance and show that the ZMP can exit the support area, and its location is representative of the imbalance state characterized by the separation between the ZMP and the CoP. Since humans exhibit this behavior, we also present proof-of-concept results of a single subject walking on an instrumented treadmill at different speeds (from slow 0.7 m/s to fast 2.0 m/s walking with increments of 0.1 m/s) with the motion recorded using an optical motion tracking system. In order to evaluate the experimental results of this model, the coefficient of determination (R2) is used to correlate the measured ground reaction forces and the resultant of inertial and gravitational forces (anteroposterior R² = 0.93, mediolateral R² = 0.89, and vertical R² = 0.86) indicating that there is a high correlation between the measurements. The results suggest that the subject exhibits a complete dynamically balanced gait during slow speeds while experiencing a controlled fall (end of swing phase) with faster speeds. This is quantified with the root-mean-square deviation (RMSD

  9. Theoretical Analysis of the Electron Spiral Toroid Concept

    NASA Technical Reports Server (NTRS)

    Cambier, Jean-Luc; Micheletti, David A.; Bushnell, Dennis M. (Technical Monitor)

    2000-01-01

    This report describes the analysis of the Electron Spiral Toroid (EST) concept being promoted by Electron Power Systems Inc. (EPS). The EST is described as a toroidal plasma structure composed Of ion and electron shells. It is claimed that the EST requires little or no external confinement, despite the extraordinarily large energy densities resulting from the self-generating magnetic fields. The present analysis is based upon documentation made available by EPS, a previous description of the model by the Massachusetts Institute of Technology (MIT), and direct discussions with EPS and MIT. It is found that claims of absolute stability and large energy storage capacities of the EST concept have not been substantiated. Notably, it can be demonstrated that the ion fluid is fundamentally unstable. Although various scenarios for ion confinement were subsequently suggested by EPS and MIT, none were found to be plausible. Although the experimental data does not prove the existence of EST configurations, there is undeniable experimental evidence that some type of plasma structures whose characteristics remain to be determined are observed. However, more realistic theoretical models must first be developed to explain their existence and properties before applications of interest to NASA can he assessed and developed.

  10. A simple method for HbF analysis.

    PubMed

    von Mandach, U; Tuchschmid, P; Huch, A; Huch, R

    1987-01-01

    Spectrophotometric methods with CO-oxymeters for measurements of carboxyhemoglobin and/or oxygen saturation in human blood include a systematic error depending on the percentage of fetal hemoglobin. It is of clinical importance to estimate the fetal hemoglobin to correct HbCO and SO2 values respectively. The described method is simple and less time consuming than conventional methods like HPLC or electrophoresis. The two measurements of oxy- and carboxyhemoglobin in the same blood sample with different oxygen saturation are needed for the estimation of the HbF and can be performed, including the deoxygenation procedure, in about 40 minutes.

  11. Simple exact analysis of the standardised mortality ratio.

    PubMed Central

    Liddell, F D

    1984-01-01

    The standardised mortality ratio is the ratio of deaths observed, D, to those expected, E, on the basis of the mortality rates of some reference population. On the usual assumptions--that D was generated by a Poisson process and that E is based on such large numbers that it can be taken as without error--the long established, but apparently little known, link between the Poisson and chi 2 distributions provides both an exact test of significance and expressions for obtaining exact (1-alpha) confidence limits on the SMR. When a table of the chi 2 distribution gives values for 1-1/2 alpha and 1/2 alpha with the required degrees of freedom, the procedures are not only precise but very simple. When the required values of chi 2 are not tabulated, only slightly less simple procedures are shown to be highly reliable for D greater than 5; they are more reliable for all D and alpha than even the best of three approximate methods. For small D, all approximations can be seriously unreliable. The exact procedures are therefore recommended for use wherever the basic assumptions (Poisson D and fixed E) apply. PMID:6707569

  12. GRETNA: a graph theoretical network analysis toolbox for imaging connectomics

    PubMed Central

    Wang, Jinhui; Wang, Xindi; Xia, Mingrui; Liao, Xuhong; Evans, Alan; He, Yong

    2015-01-01

    Recent studies have suggested that the brain’s structural and functional networks (i.e., connectomics) can be constructed by various imaging technologies (e.g., EEG/MEG; structural, diffusion and functional MRI) and further characterized by graph theory. Given the huge complexity of network construction, analysis and statistics, toolboxes incorporating these functions are largely lacking. Here, we developed the GRaph thEoreTical Network Analysis (GRETNA) toolbox for imaging connectomics. The GRETNA contains several key features as follows: (i) an open-source, Matlab-based, cross-platform (Windows and UNIX OS) package with a graphical user interface (GUI); (ii) allowing topological analyses of global and local network properties with parallel computing ability, independent of imaging modality and species; (iii) providing flexible manipulations in several key steps during network construction and analysis, which include network node definition, network connectivity processing, network type selection and choice of thresholding procedure; (iv) allowing statistical comparisons of global, nodal and connectional network metrics and assessments of relationship between these network metrics and clinical or behavioral variables of interest; and (v) including functionality in image preprocessing and network construction based on resting-state functional MRI (R-fMRI) data. After applying the GRETNA to a publicly released R-fMRI dataset of 54 healthy young adults, we demonstrated that human brain functional networks exhibit efficient small-world, assortative, hierarchical and modular organizations and possess highly connected hubs and that these findings are robust against different analytical strategies. With these efforts, we anticipate that GRETNA will accelerate imaging connectomics in an easy, quick and flexible manner. GRETNA is freely available on the NITRC website.1 PMID:26175682

  13. Electrochemical, spectroscopic and theoretical studies of a simple bifunctional cobalt corrole catalyst for oxygen evolution and hydrogen production.

    PubMed

    Lei, Haitao; Han, Ali; Li, Fengwang; Zhang, Meining; Han, Yongzhen; Du, Pingwu; Lai, Wenzhen; Cao, Rui

    2014-02-07

    Six cobalt and manganese corrole complexes were synthesized and examined as single-site catalysts for water splitting. The simple cobalt corrole [Co(tpfc)(py)2] (1, tpfc = 5,10,15-tris(pentafluorophenyl)corrole, py = pyridine) catalyzed both water oxidation and proton reduction efficiently. By coating complex 1 onto indium tin oxide (ITO) electrodes, the turnover frequency for electrocatalytic water oxidation was 0.20 s(−1) at 1.4 V (vs. Ag/AgCl, pH = 7), and it was 1010 s(−1) for proton reduction at −1.0 V (vs. Ag/AgCl, pH = 0.5). The stability of 1 for catalytic oxygen evolution and hydrogen production was evaluated by electrochemical, UV-vis and mass measurements, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), which confirmed that 1 was the real molecular catalyst. Titration and UV-vis experiments showed that the pyridine group on Co dissociated at the beginning of catalysis, which was critical to subsequent activation of water. A proton-coupled electron transfer process was involved based on the pH dependence of the water oxidation reaction catalyzed by 1. As for manganese corroles 2–6, although their oxidizing powers were comparable to that of 1, they were not as stable as 1 and underwent decomposition at the electrode. Density functional theory (DFT) calculations indicated that water oxidation by 1 was feasible through a proposed catalytic cycle. The formation of an O–O bond was suggested to be the rate-determining step, and the calculated activation barrier of 18.1 kcal mol(−1) was in good agreement with that obtained from experiments.

  14. Working with Simple Machines

    ERIC Educational Resources Information Center

    Norbury, John W.

    2006-01-01

    A set of examples is provided that illustrate the use of work as applied to simple machines. The ramp, pulley, lever and hydraulic press are common experiences in the life of a student, and their theoretical analysis therefore makes the abstract concept of work more real. The mechanical advantage of each of these systems is also discussed so that…

  15. Development of Novel, Simple, Multianalyte Sensors for Remote Environmental Analysis

    SciTech Connect

    Asher, Sanford A.

    2000-06-01

    We will develop simple, inexpensive new chemical sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of environmental pollutants such as cations of Pb, U, Pu, Sr, Hg, Cs, Co as well as other species. We will develop inexpensive chemical test strips which can be immersed in water to determine these analytes in the field. We will also develop arrays of these chemical sensing materials which will be attached to fiber optic bundles to be used as rugged multichannel optrodes to simultaneously monitor numerous analytes remotely in hostile environments. These sensing materials are based on the intelligent polymerized crystalline colloidal array (PCCA) technology we recently developed. This sensing motif utilizes a mesoscopically periodic array of colloidal particles polymerized into an acrylamide hydrogel. This array Bragg diffracts light in the visible spectral region due to the periodic array of colloidal particles. This material also contains chelating agents for the analytes of interest. When an analyte binds, its charge is immobilized within the acrylamide hydrogel. The resulting Donnan potential causes an osmotic pressure which swells the array proportional to the concentration of analyte bound. The diffracted wavelength shifts and the color changes. The change in the wavelength diffracted reports on the identity and concentration of the target analyte. Our successful development of these simple, inexpensive highly sensitive chemical sensing optrodes, which are easily coupled to simple optical instrumentation, could revolutionize environmental monitoring. In addition, we will develop highly rugged versions, which can be attached to core penetrometers and which can be used to determine analytes in buried core samples. Research Progress and Implications This report summarizes work after 21 months of a three year project. We have developed a new method to crosslink our PCCA sensing

  16. Advances in multiscale theoretical analysis and imaging aspects of turbulence

    NASA Astrophysics Data System (ADS)

    Shockro, Jennifer

    The work presented in this dissertation is focused on two aspects related to turbulent flow. The first of these is the one-dimensional theoretical analysis of the logarithmic spiral in terms of fractal dimension and spectrum. The second is on imaging methodologies and analysis of turbulent jet scalar interfaces in atmospheric conditions, with broad applicability to various studies where turbulence has a key role, such as urban contaminant dispersion or free space laser communications. The logarithmic spiral is of particular interest to studies of turbulence and natural phenomena as it appears frequently in nature with the "Golden Ratio" and is thought to play an important role in turbulent mixing. It is also an inherently anisotropic geometric structure and therefore provides information towards examining phenomena in which anisotropic properties might be expected to appear and is thought to be present as a structure within the fine scales of the turbulent hierarchy. In this work it is subjected to one-dimensional theoretical analysis, focusing on the development of a probability density function (pdf) for the spiral and the relation of the pdf to its fractal dimension. Results indicate that the logarithmic spiral does not have a constant fractal dimension and thus that it does not exhibit any form of self-similar statistical behavior, supporting previous theoretical suppositions about behavior at the fine scales within the turbulent hierarchy. A signal is developed from the pdf in order to evaluate its power spectrum. Results of this analysis provide information about the manner in which energy is carried at different scales of the spiral. To our knowledge, the logarithmic spiral in particular has not yet been examined in this fashion in literature. In order to further investigate this object, the multiscale minima meshless (M(3) ) method isextended and employed computationally to the two-dimensional logarithmic spiral as well as to experimental images of a

  17. Simple bounds on limit loads by elastic finite element analysis

    SciTech Connect

    Mackenzie, D.; Nadarajah, C.; Shi, J.; Boyle, J.T. . Dept. of Mechanical Engineering)

    1993-02-01

    A method for bounding limit loads by an iterative elastic continuum finite element analysis procedure, referred to as the elastic compensation method, is proposed. A number of sample problems are considered, based on both exact solutions and finite element analysis, and it is concluded that the method may be used to obtain limit-load bounds for pressure vessel design by analysis applications with useful accuracy.

  18. Large deviation analysis of a simple information engine.

    PubMed

    Maitland, Michael; Grosskinsky, Stefan; Harris, Rosemary J

    2015-11-01

    Information thermodynamics provides a framework for studying the effect of feedback loops on entropy production. It has enabled the understanding of novel thermodynamic systems such as the information engine, which can be seen as a modern version of "Maxwell's Dæmon," whereby a feedback controller processes information gained by measurements in order to extract work. Here, we analyze a simple model of such an engine that uses feedback control based on measurements to obtain negative entropy production. We focus on the distribution and fluctuations of the information obtained by the feedback controller. Significantly, our model allows an analytic treatment for a two-state system with exact calculation of the large deviation rate function. These results suggest an approximate technique for larger systems, which is corroborated by simulation data.

  19. A simple flow analysis of diffuser-getter-diffuser systems

    SciTech Connect

    Klein, J. E.; Howard, D. W.

    2008-07-15

    Tritium clean-up systems typically deploy gas processing technologies between stages of palladium-silver (Pd/Ag) diffusers/permeators. The number of diffusers positioned before and after a gas clean-up process to obtain optimal system performance will vary with feed gas inert composition. A simple method to analyze optimal diffuser configuration is presented. The method assumes equilibrium across the Pd/Ag tubes and system flows are limited by diffuser vacuum pump speeds preceding or following the clean-up process. A plot of system feed as a function of inert feed gas composition for various diffuser configuration allows selection of a diffuser configuration for maximum throughput based on feed gas composition. (authors)

  20. Large deviation analysis of a simple information engine

    NASA Astrophysics Data System (ADS)

    Maitland, Michael; Grosskinsky, Stefan; Harris, Rosemary J.

    2015-11-01

    Information thermodynamics provides a framework for studying the effect of feedback loops on entropy production. It has enabled the understanding of novel thermodynamic systems such as the information engine, which can be seen as a modern version of "Maxwell's Dæmon," whereby a feedback controller processes information gained by measurements in order to extract work. Here, we analyze a simple model of such an engine that uses feedback control based on measurements to obtain negative entropy production. We focus on the distribution and fluctuations of the information obtained by the feedback controller. Significantly, our model allows an analytic treatment for a two-state system with exact calculation of the large deviation rate function. These results suggest an approximate technique for larger systems, which is corroborated by simulation data.

  1. The graph theoretical analysis of the SSVEP harmonic response networks.

    PubMed

    Zhang, Yangsong; Guo, Daqing; Cheng, Kaiwen; Yao, Dezhong; Xu, Peng

    2015-06-01

    Steady-state visually evoked potentials (SSVEP) have been widely used in the neural engineering and cognitive neuroscience researches. Previous studies have indicated that the SSVEP fundamental frequency responses are correlated with the topological properties of the functional networks entrained by the periodic stimuli. Given the different spatial and functional roles of the fundamental frequency and harmonic responses, in this study we further investigated the relation between the harmonic responses and the corresponding functional networks, using the graph theoretical analysis. We found that the second harmonic responses were positively correlated to the mean functional connectivity, clustering coefficient, and global and local efficiencies, while negatively correlated with the characteristic path lengths of the corresponding networks. In addition, similar pattern occurred with the lowest stimulus frequency (6.25 Hz) at the third harmonic responses. These findings demonstrate that more efficient brain networks are related to larger SSVEP responses. Furthermore, we showed that the main connection pattern of the SSVEP harmonic response networks originates from the interactions between the frontal and parietal-occipital regions. Overall, this study may bring new insights into the understanding of the brain mechanisms underlying SSVEP.

  2. A novel theoretical approach to the analysis of dendritic transients.

    PubMed Central

    Agmon-Snir, H

    1995-01-01

    A novel theoretical framework for analyzing dendritic transients is introduced. This approach, called the method of moments, is an extension of Rall's cable theory for dendrites. It provides analytic investigation of voltage attenuation, signal delay, and synchronization problems in passive dendritic trees. In this method, the various moments of a transient signal are used to characterize the properties of the transient. The strength of the signal is measured by the time integral of the signal, its characteristic time is determined by its centroid ("center of gravity"), and the width of the signal is determined by a measure similar to the standard deviation in probability theory. Using these signal properties, the method of moments provides theorems, expressions, and efficient algorithms for analyzing the voltage response in arbitrary passive trees. The method yields new insights into spatiotemporal integration, coincidence detection mechanisms, and the properties of local interactions between synaptic inputs in dendritic trees. The method can also be used for matching dendritic neuron models to experimental data and for the analysis of synaptic inputs recorded experimentally. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 10 PMID:8580308

  3. GraTeLPy: graph-theoretic linear stability analysis

    PubMed Central

    2014-01-01

    Background A biochemical mechanism with mass action kinetics can be represented as a directed bipartite graph (bipartite digraph), and modeled by a system of differential equations. If the differential equations (DE) model can give rise to some instability such as multistability or Turing instability, then the bipartite digraph contains a structure referred to as a critical fragment. In some cases the existence of a critical fragment indicates that the DE model can display oscillations for some parameter values. We have implemented a graph-theoretic method that identifies the critical fragments of the bipartite digraph of a biochemical mechanism. Results GraTeLPy lists all critical fragments of the bipartite digraph of a given biochemical mechanism, thus enabling a preliminary analysis on the potential of a biochemical mechanism for some instability based on its topological structure. The correctness of the implementation is supported by multiple examples. The code is implemented in Python, relies on open software, and is available under the GNU General Public License. Conclusions GraTeLPy can be used by researchers to test large biochemical mechanisms with mass action kinetics for their capacity for multistability, oscillations and Turing instability. PMID:24572152

  4. Theoretical analysis of magnetic field interactions with aortic blood flow

    SciTech Connect

    Kinouchi, Y.; Yamaguchi, H.; Tenforde, T.S.

    1996-04-01

    The flow of blood in the presence of a magnetic field gives rise to induced voltages in the major arteries of the central circulatory system. Under certain simplifying conditions, such as the assumption that the length of major arteries (e.g., the aorta) is infinite and that the vessel walls are not electrically conductive, the distribution of induced voltages and currents within these blood vessels can be calculated with reasonable precision. However, the propagation of magnetically induced voltages and currents from the aorta into neighboring tissue structures such as the sinuatrial node of the heart has not been previously determined by any experimental or theoretical technique. In the analysis presented in this paper, a solution of the complete Navier-Stokes equation was obtained by the finite element technique for blood flow through the ascending and descending aortic vessels in the presence of a uniform static magnetic field. Spatial distributions of the magnetically induced voltage and current were obtained for the aortic vessel and surrounding tissues under the assumption that the wall of the aorta is electrically conductive. Results are presented for the calculated values of magnetically induced voltages and current densities in the aorta and surrounding tissue structures, including the sinuatrial node, and for their field-strength dependence. In addition, an analysis is presented of magnetohydrodynamic interactions that lead to a small reduction of blood volume flow at high field levels above approximately 10 tesla (T). Quantitative results are presented on the offsetting effects of oppositely directed blood flows in the ascending and descending aortic segments, and a quantitative estimate is made of the effects of assuming an infinite vs. a finite length of the aortic vessel in calculating the magnetically induced voltage and current density distribution in tissue.

  5. PDT driven by energy-converting materials: a theoretical analysis

    NASA Astrophysics Data System (ADS)

    Finlay, Jarod C.

    2009-02-01

    Materials have been developed which absorb radiation of one energy and emit light of another. We present a theoretical analysis of the use of these materials as light sources for photodynamic therapy (PDT). The advantage of this strategy is that radiation of higher particle energy (e.g. x ray or electron beam) or lower photon energy (e.g. infra-red) may have more favorable penetration in tissue or more readily available radiation sources than the radiation absorbed by the sensetizer. Our analysis is based on the transfer of energy from radiation fields to visible light. We analyze two scenarios: PDT pumped by (1) infrared light in a two-photon process and (2) ionizing radiation. In each case, we assume that the converting material and the sensitizer are matched sufficiently that the transfer of energy between them is essentially lossless. For the infinite and semiinfinite geometries typically used in PDT, we calculate the resulting photodynamic dose distribution, and compare it to the dose distribution expected for conventional PDT. We also calculate the dose of the incident beam (ionizing or infrared radiation) required to produce PDT-induced tumoricidal effects, and evaluate the expected toxicity in surrounding normal tissue. The toxicity is assumed to arise from thermal effects and acute ionizing radiation effects, for infrared and ionizing radiation, respectively. Our results predict that ionizing radiation will produce dose-limiting toxicity in most conventional geometries as a result of the high toxicity per unit energy of ionizing radiation. For infrared radiation, we predict that the toxicity can be moderated by proper choice of sensitizer and irradiation geometry and fractionation.

  6. Pre/Post Data Analysis - Simple or Is It?

    NASA Technical Reports Server (NTRS)

    Feiveson, Al; Fiedler, James; Ploutz-Snyder, Robert

    2011-01-01

    This slide presentation reviews some of the problems of data analysis in analyzing pre and post data. Using as an example, ankle extensor strength (AES) experiments, to measure bone density loss during bed rest, the presentation discusses several questions: (1) How should we describe change? (2) Common analysis methods for comparing post to pre results. (3) What do we mean by "% change"? and (4) What are we testing when we compare % changes?

  7. Analysis of Poisson frequency data under a simple crossover trial.

    PubMed

    Lui, Kung-Jong; Chang, Kuang-Chao

    2016-02-01

    When the frequency of occurrence for an event of interest follows a Poisson distribution, we develop asymptotic and exact procedures for testing non-equality, non-inferiority and equivalence, as well as asymptotic and exact interval estimators for the ratio of mean frequencies between two treatments under a simple crossover design. Using Monte Carlo simulations, we evaluate the performance of these test procedures and interval estimators in a variety of situations. We note that all asymptotic test procedures developed here can generally perform well with respect to Type I error and can be preferable to the exact test procedure with respect to power if the number of patients per group is moderate or large. We further find that in these cases the asymptotic interval estimator with the logarithmic transformation can be more precise than the exact interval estimator without sacrificing the accuracy with respect to the coverage probability. However, the exact test procedure and exact interval estimator can be of use when the number of patients per group is small. We use a double-blind randomized crossover trial comparing salmeterol with a placebo in exacerbations of asthma to illustrate the practical use of these estimators.

  8. Development of Novel, Simple, Multianalyte Sensors For Remote Environmental Analysis

    SciTech Connect

    Asher, Sanfor A.

    1999-06-01

    We will develop simple, inexpensive new chemical sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of environmental pollutants such as cations of Pb, U, Pu, Sr, Hg, Cs, Co as well as other species. We will develop inexpensive chemical test strips which can be immersed in water to determine these analytes in the field. We will also develop arrays of these chemical sensing materials which will be attached to fiber optic bundles to be used as rugged multichannel optrodes to simultaneously monitor numerous analytes remotely in hostile environments. These sensing materials are based on the intelligent polymerized crystalline colloidal array (PCCA) technology we recently developed. This sensing motif utilizes a mesoscopically periodic array of colloidal particles polymerized into an acrylamide hydrogel. This array Bragg diffracts light in the visible spectral region due to the periodic array of colloidal particles. This material also contains chelating agents for the analytes of interest. When an analyte binds, its charge is immobilized within the acrylamide hydrogel. The resulting Donnan potential causes an osmotic pressure which swells the array proportional to the concentration of analyte bound. The diffracted wavelength shifts and the color changes. The change in the wavelength diffracted reports on the identity and concentration of the target analyte.

  9. Stability analysis of a simple rheonomic nonholonomic constrained system

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Liu, Shi-Xing; Mei, Feng-Xing

    2016-12-01

    It is a difficult problem to study the stability of the rheonomic and nonholonomic mechanical systems. Especially it is difficult to construct the Lyapunov function directly from the differential equation. But the gradient system is exactly suitable to study the stability of a dynamical system with the aid of the Lyapunov function. The stability of the solution for a simple rheonomic nonholonomic constrained system is studied in this paper. Firstly, the differential equations of motion of the system are established. Secondly, a problem in which the generalized forces are exerted on the system such that the solution is stable is proposed. Finally, the stable solutions of the rheonomic nonholonomic system can be constructed by using the gradient systems. Project supported by the National Natural Science Foundation of China (Grant Nos. 11272050, 11202090, 11472124, 11572034, and 11572145), the Science and Technology Research Project of Liaoning Province, China (Grant No. L2013005), China Postdoctoral Science Foundation (Grant No. 2014M560203), and the Doctor Start-up Fund in Liaoning Province of China (Grant No. 20141050).

  10. A theoretical analysis of optimum consumer population and its control.

    PubMed

    Jiang, Z; Mao, Z; Wang, H

    1994-01-01

    Material production is related to population consumption in every society. Consumption also constantly transforms materials, energy, and information. In this sense, consumption provides both impetus for material production and a self-adapting mechanism for population development and control. Population structure variables affecting economic production can be divided according to non-adults, working-age work force and the elderly, social status, and urban-rural structure. The consumptive structures among people of different social status reflect different needs for social and economic development. The theoretical calculation of the consumer population in the national economy demonstrates that the national income in a certain year of a given national economy equals consumption fund plus accumulation fund where consumption fund includes social consumption fund and residential consumption fund. Social consumption fund is spent mostly on public utilities, administrative management, national defense, education, public health and urban construction, as well as on environment management and disaster relief. The residential consumption fund can be divided into basic expenditure such as clothing, food, shelter and transportation, and self-improvement expenditure such as recreation, education, and travel. As a result of economic development, not only the percentage of the expenditure on food will decrease and the percentage of the expenditure on clothing, shelter, transportation, and other daily necessities will increase, but expenses on recreation and education also will grow. Residential consumption is divided into subsistence consumption (Type I consumption) and self-improvement (recreation and education) consumption (Type II consumption) in order to determine consumer population and the degree of urbanization and its impact upon social and economic development. A moderate consumer population model of urban and rural areas was established by using the urban and rural

  11. Confluence Analysis for Distributed Programs: A Model-Theoretic Approach

    DTIC Science & Technology

    2011-12-18

    Dedalus language, we will refer to two run- ning examples for the remainder of the paper. Example 7. A simple asynchronous marriage ceremony...distributed commit protocols and marriage ceremonies [22]. For simplicity (and felicity), Example 7 presents a simple asynchronous voting program with a...fixed set of members: a bride and a groom. The marriage is off (runaway() is true) if one party says “I do” and the other does not. However, the Dedalus

  12. The analysis of non-linear dynamic behavior (including snap-through) of postbuckled plates by simple analytical solution

    NASA Technical Reports Server (NTRS)

    Ng, C. F.

    1988-01-01

    Static postbuckling and nonlinear dynamic analysis of plates are usually accomplished by multimode analyses, although the methods are complicated and do not give straightforward understanding of the nonlinear behavior. Assuming single-mode transverse displacement, a simple formula is derived for the transverse load displacement relationship of a plate under in-plane compression. The formula is used to derive a simple analytical expression for the static postbuckling displacement and nonlinear dynamic responses of postbuckled plates under sinusoidal or random excitation. Regions with softening and hardening spring behavior are identified. Also, the highly nonlinear motion of snap-through and its effects on the overall dynamic response can be easily interpreted using the single-mode formula. Theoretical results are compared with experimental results obtained using a buckled aluminum panel, using discrete frequency and broadband point excitation. Some important effects of the snap-through motion on the dynamic response of the postbuckled plates are found.

  13. Insights into Fourier Synthesis and Analysis: Part I--Using Simple Programs and Equipment.

    ERIC Educational Resources Information Center

    Moore, Guy S. M.

    1988-01-01

    Introduced is a unique generation method of Fourier series requiring simple mathematical skills and using computer programs. Discusses Fourier synthesis by microcomputer, and Fourier analysis with simple equipment. Shown are a circuit diagram, computer programs, monitor displays and tables of data. (YP)

  14. Developmental Change in the Relation between Simple and Complex Spans: A Meta-Analysis

    ERIC Educational Resources Information Center

    Tillman, Carin M.

    2011-01-01

    In the present meta-analysis the effects of developmental level on the correlation between simple and complex span tasks were investigated. Simple span-complex span correlation coefficients presented in 52 independent samples (7,060 participants) were regressed on a variable representing mean age of sample (range: 4.96-22.80 years), using analyses…

  15. A Simple Theoretical Analysis and Experimental Investigation of Burning Processes for Stick Propellant

    DTIC Science & Technology

    1983-07-01

    LEM , U. Fortune R. Zastrow Rock Island, IL 61299 Commander US Army Watervllet Arsenal ATTN: SARWV-RD, R. Thierry Watervllet, NY 12189 Di...DISTRIBUTION LIST No. Of Copies Organization Rockwell International Rocketdyne Division ATTN: BA08 J. E. Flanagan J. Grey 6633 Canoga Avenue

  16. Simple Sensitivity Analysis for Orion Guidance Navigation and Control

    NASA Technical Reports Server (NTRS)

    Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar

    2013-01-01

    The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch. We describe in this paper a sensitivity analysis tool ("Critical Factors Tool" or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.

  17. Towards theoretical analysis of long-range proton transfer kinetics in biomolecular pumps

    PubMed Central

    König, P. H.; Ghosh, N.; Hoffmann, M.; Elstner, M.; Tajkhorshid, E.; Frauenheim, Th.; Cui, Q.

    2008-01-01

    Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, a number of technical developments were made in the framework of QM/MM simulations. A set of collective reaction co-ordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly non-linear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework. PMID:16405327

  18. Toward theoretical analysis of long-range proton transfer kinetics in biomolecular pumps.

    PubMed

    König, P H; Ghosh, N; Hoffmann, M; Elstner, M; Tajkhorshid, E; Frauenheim, Th; Cui, Q

    2006-01-19

    Motivated by the long-term goal of theoretically analyzing long-range proton transfer (PT) kinetics in biomolecular pumps, researchers made a number of technical developments in the framework of quantum mechanics-molecular mechanics (QM/MM) simulations. A set of collective reaction coordinates is proposed for characterizing the progress of long-range proton transfers; unlike previous suggestions, the new coordinates can describe PT along highly nonlinear three-dimensional pathways. Calculations using a realistic model of carbonic anhydrase demonstrated that adiabatic mapping using these collective coordinates gives reliable energetics and critical geometrical parameters as compared to minimum energy path calculations, which suggests that the new coordinates can be effectively used as reaction coordinate in potential of mean force calculations for long-range PT in complex systems. In addition, the generalized solvent boundary potential was implemented in the QM/MM framework for rectangular geometries, which is useful for studying reactions in membrane systems. The resulting protocol was found to produce water structure in the interior of aquaporin consistent with previous studies including a much larger number of explicit solvent and lipid molecules. The effect of electrostatics for PT through a membrane protein was also illustrated with a simple model channel embedded in different dielectric continuum environments. The encouraging results observed so far suggest that robust theoretical analysis of long-range PT kinetics in biomolecular pumps can soon be realized in a QM/MM framework.

  19. Theoretical analysis and experimental verification on optical rotational Doppler effect.

    PubMed

    Zhou, Hailong; Fu, Dongzhi; Dong, Jianji; Zhang, Pei; Zhang, Xinliang

    2016-05-02

    We present a theoretical model to sufficiently investigate the optical rotational Doppler effect based on modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the difference of mode index between input and output orbital angular momentum (OAM) light, and linear to the rotating speed of spinning object as well. An experiment is carried out to verify the theoretical model. We explicitly suggest that the spatial spiral phase distribution of spinning object determines the frequency content. The theoretical model makes us better understand the physical processes of rotational Doppler effect, and thus has many related application fields, such as detection of rotating bodies, imaging of surface and measurement of OAM light.

  20. Simple and clean determination of tetracyclines by flow injection analysis

    NASA Astrophysics Data System (ADS)

    Rodríguez, Michael Pérez; Pezza, Helena Redigolo; Pezza, Leonardo

    2016-01-01

    An environmentally reliable analytical methodology was developed for direct quantification of tetracycline (TC) and oxytetracycline (OTC) using continuous flow injection analysis with spectrophotometric detection. The method is based on the diazo coupling reaction between the tetracyclines and diazotized sulfanilic acid in a basic medium, resulting in the formation of an intense orange azo compound that presents maximum absorption at 434 nm. Experimental design was used to optimize the analytical conditions. The proposed technique was validated over the concentration range of 1 to 40 μg mL- 1, and was successfully applied to samples of commercial veterinary pharmaceuticals. The detection (LOD) and quantification (LOQ) limits were 0.40 and 1.35 μg mL- 1, respectively. The samples were also analyzed by an HPLC method, and the results showed agreement with the proposed technique. The new flow injection method can be immediately used for quality control purposes in the pharmaceutical industry, facilitating monitoring in real time during the production processes of tetracycline formulations for veterinary use.

  1. Positive Action Programmes for Women. 1. A Theoretical Analysis.

    ERIC Educational Resources Information Center

    Vogel-Polsky, Eliane

    1985-01-01

    The author discusses the theoretical aspects of positive action programs for women. In looking at the results achieved by the various laws and institutional machinery introduced in Western Europe to enforce equal pay and equal treatment for men and women in employment, she concludes that no notable progress has been made over the past 10 years.…

  2. Theoretical and Experimental Analysis of the Physics of Water Rockets

    ERIC Educational Resources Information Center

    Barrio-Perotti, R.; Blanco-Marigorta, E.; Fernandez-Francos, J.; Galdo-Vega, M.

    2010-01-01

    A simple rocket can be made using a plastic bottle filled with a volume of water and pressurized air. When opened, the air pressure pushes the water out of the bottle. This causes an increase in the bottle momentum so that it can be propelled to fairly long distances or heights. Water rockets are widely used as an educational activity, and several…

  3. CMS Made Simple: A ROOT-less workflow for educating undergraduates about CMS data analysis

    NASA Astrophysics Data System (ADS)

    Muenkel, Jessica; Bellis, Matthew; CMS Collaboration

    2015-04-01

    Involving students in research is an important part of the undergraduate experience. By working on a problem where the answer is unknown, students apply what they learn in the classroom to a real-world challenge, which reinforce the more theoretical aspects of their courses. Many undergraduates are drawn to the idea of working on big particle physics experiments like CMS (Compact Muon Solenoid) at the Large Hadron Collider (LHC), but the threshold is high for them to contribute to an analysis. Those of us who perform research spend much of our time debugging scripts and C + + code, usually specific to that one experiment. If an undergraduate is not going on to grad school in particle physics, much of that work can be wasted on them. However, there are many general skills that students can learn by working on parts of a particle physics analysis (relativistic kinematics, statistics, coding, etc.), and so it is worth trying to lower the threshold to engage students. In this poster, we present a suite of datasets and tools, built around the Python programming language that simplify the workflow and allow a student to interact with CMS data immediately. While it is a staple of the particle physics community, we avoid using the ROOT toolkit, so as to stick to more broadly used tools that the students can take with them. These tools are being used to supplement the educational examples for the CERN Open Data Portal, a project to make LHC datasets available to the general public. The successes and limitations of CMS Made Simple will be discussed and links are provided to these tools.

  4. Theoretical Analysis of Positional Uncertainty in Direct Georeferencing

    NASA Astrophysics Data System (ADS)

    Coskun Kiraci, Ali; Toz, Gonul

    2016-10-01

    GNSS/INS system composed of Global Navigation Satellite System and Inertial Navigation System together can provide orientation parameters directly by the observations collected during the flight. Thus orientation parameters can be obtained by GNSS/INS integration process without any need for aero triangulation after the flight. In general, positional uncertainty can be estimated with known coordinates of Ground Control Points (GCP) which require field works such as marker construction and GNSS measurement leading additional cost to the project. Here the question arises what should be the theoretical uncertainty of point coordinates depending on the uncertainties of orientation parameters. In this study the contribution of each orientation parameter on positional uncertainty is examined and theoretical positional uncertainty is computed without GCP measurement for direct georeferencing using a graphical user interface developed in MATLAB.

  5. A Measurement-Theoretic Analysis of the Fuzzy Logic Model of Perception.

    ERIC Educational Resources Information Center

    Crowther, Court S.; And Others

    1995-01-01

    The fuzzy logic model of perception (FLMP) is analyzed from a measurement-theoretic perspective. The choice rule of FLMP is shown to be equivalent to a version of the Rasch model. In fact, FLMP can be reparameterized as a simple two-category logit model. (SLD)

  6. Analysis of NASA JP-4 fire tests data and development of a simple fire model

    NASA Technical Reports Server (NTRS)

    Raj, P.

    1980-01-01

    The temperature, velocity and species concentration data obtained during the NASA fire tests (3m, 7.5m and 15m diameter JP-4 fires) were analyzed. Utilizing the data analysis, a sample theoretical model was formulated to predict the temperature and velocity profiles in JP-4 fires. The theoretical model, which does not take into account the detailed chemistry of combustion, is capable of predicting the extent of necking of the fire near its base.

  7. Extending and automating a Systems-Theoretic hazard analysis for requirements generation and analysis.

    SciTech Connect

    Thomas, John

    2012-05-01

    Systems Theoretic Process Analysis (STPA) is a powerful new hazard analysis method designed to go beyond traditional safety techniques - such as Fault Tree Analysis (FTA) - that overlook important causes of accidents like flawed requirements, dysfunctional component interactions, and software errors. While proving to be very effective on real systems, no formal structure has been defined for STPA and its application has been ad-hoc with no rigorous procedures or model-based design tools. This report defines a formal mathematical structure underlying STPA and describes a procedure for systematically performing an STPA analysis based on that structure. A method for using the results of the hazard analysis to generate formal safety-critical, model-based system and software requirements is also presented. Techniques to automate both the analysis and the requirements generation are introduced, as well as a method to detect conflicts between the safety and other functional model-based requirements during early development of the system.

  8. Task Analysis in Instructional Program Development. Theoretical Paper No. 52.

    ERIC Educational Resources Information Center

    Bernard, Michael E.

    A review of task analysis procedures beginning with the military training and systems development approach and covering the more recent work of Gagne, Klausmeier, Merrill, Resnick, and others is presented along with a plan for effective instruction based on the review of task analysis. Literature dealing with the use of task analysis in programmed…

  9. Anion order in perovskites: a group-theoretical analysis.

    PubMed

    Talanov, M V; Shirokov, V B; Talanov, V M

    2016-03-01

    Anion ordering in the structure of cubic perovskite has been investigated by the group-theoretical method. The possibility of the existence of 261 ordered low-symmetry structures, each with a unique space-group symmetry, is established. These results include five binary and 14 ternary anion superstructures. The 261 idealized anion-ordered perovskite structures are considered as aristotypes, giving rise to different derivatives. The structures of these derivatives are formed by tilting of BO6 octahedra, distortions caused by the cooperative Jahn-Teller effect and other physical effects. Some derivatives of aristotypes exist as real substances, and some as virtual ones. A classification of aristotypes of anion superstructures in perovskite is proposed: the AX class (the simultaneous ordering of A cations and anions in cubic perovskite structure), the BX class (the simultaneous ordering of B cations and anions) and the X class (the ordering of anions only in cubic perovskite structure). In most perovskites anion ordering is accompanied by cation ordering. Therefore, the main classes of anion order in perovskites are the AX and BX classes. The calculated structures of some anion superstructures are reported. Comparison of predictions and experimentally investigated anion superstructures shows coherency of theoretical and experimental results.

  10. An information theoretic synthesis and analysis of Compton profiles

    NASA Astrophysics Data System (ADS)

    Sears, Stephen B.; Gadre, Shridhar R.

    1981-11-01

    The information theoretic technique of entropy maximization is applied to Compton profile (CP) data, employing single and double distribution moments theoretic quantities—Shannon entropies, information contents, and surprisals—are also presented. Based upon the ''sum'' constraint

  11. An Isotopic Dilution Experiment Using Liquid Scintillation: A Simple Two-System, Two-Phase Analysis.

    ERIC Educational Resources Information Center

    Moehs, Peter J.; Levine, Samuel

    1982-01-01

    A simple isotonic, dilution analysis whose principles apply to methods of more complex radioanalyses is described. Suitable for clinical and instrumental analysis chemistry students, experimental manipulations are kept to a minimum involving only aqueous extraction before counting. Background information, procedures, and results are discussed.…

  12. Experimental and theoretical analysis of long waves transformation on a sloping beach

    NASA Astrophysics Data System (ADS)

    Szmidt, K.; Staroszczyk, R.; Hedzielski, B.

    2009-09-01

    Transformation of long water waves on a sloping beach has been investigated, both experimentally and theoretically. Experiments have been conducted in a 64 m long and 0.6 m wide laboratory flume at the Institute of Hydro-Engineering, Polish Academy of Sciences, in Gdansk, Poland. Plane monochromatic waves have been generated by a piston-type wave maker situated at one end of the flume, and the sloping beach has been modelled by an inclined rigid ramp, of the slope equal to either 10 or 15 per cent, placed at a distance of 12 m from the generator wall. The water wave parameters have been recorded by a set of gauges installed along the flume, both in its constant- and varying-depth parts. Additionally, the run-up of the wave has been measured by a special conductivity gauge mounted on the ramp along the wave propagation direction. The experiments have been carried out for a wide range of wave lengths and amplitudes, falling, however, into the long-wave regime. The theoretical analysis of the wave propagation phenomenon has been performed by solving the problem in Lagrangian coordinates, since this permits simple formulation of boundary conditions on the moving boundaries of the fluid domain. However, the price for it is a more complicated structure of equations describing the fluid motion, compared to more traditional approaches based on the Eulerian description. In order to simplify the analysis, the shallow water approximation is applied. An essential simplification, on which the theoretical formulation proposed in this work is based, is a kinematical assumption that fluid motion is "columnar"; that is, the vertical material lines of fluid particles remain vertical during the motion. Fundamental equations of the theoretical description of the problem have been derived by following the Hamilton principle. Owing to the above kinematical assumption on the fluid motion, all the integrands in the action integral are expressed in terms of only the fluid horizontal

  13. Theoretical and software considerations for nonlinear dynamic analysis

    NASA Technical Reports Server (NTRS)

    Schmidt, R. J.; Dodds, R. H., Jr.

    1983-01-01

    In the finite element method for structural analysis, it is generally necessary to discretize the structural model into a very large number of elements to accurately evaluate displacements, strains, and stresses. As the complexity of the model increases, the number of degrees of freedom can easily exceed the capacity of present-day software system. Improvements of structural analysis software including more efficient use of existing hardware and improved structural modeling techniques are discussed. One modeling technique that is used successfully in static linear and nonlinear analysis is multilevel substructuring. This research extends the use of multilevel substructure modeling to include dynamic analysis and defines the requirements for a general purpose software system capable of efficient nonlinear dynamic analysis. The multilevel substructuring technique is presented, the analytical formulations and computational procedures for dynamic analysis and nonlinear mechanics are reviewed, and an approach to the design and implementation of a general purpose structural software system is presented.

  14. A Theoretical Analysis of the k-Satisfiability Search Space

    NASA Astrophysics Data System (ADS)

    Sutton, Andrew M.; Howe, Adele E.; Whitley, L. Darrell

    Local search algorithms perform surprisingly well on the k-satisfiability (k-SAT) problem. However, few theoretical analyses of the k-SAT search space exist. In this paper we study the search space of the k-SAT problem and show that it can be analyzed by a decomposition. In particular, we prove that the objective function can be represented as a superposition of exactly k elementary landscapes. We show that this decomposition allows us to immediately compute the expectation of the objective function evaluated across neighboring points. We use this result to prove previously unknown bounds for local maxima and plateau width in the 3-SAT search space. We compute these bounds numerically for a number of instances and show that they are non-trivial across a large set of benchmarks.

  15. Theoretical Analysis Of A Sagnac Fiber Optic Interferometer

    NASA Astrophysics Data System (ADS)

    Szustakowski, Mieczyslaw; Jaroszewicz, Leszek R.

    1990-04-01

    The analytical description of a closed optical fiber interferometer system based on Jones calculus is presented. This calculus adapation for the optical fiber elements analysis allows for a uniform description of system built on the basis of a single-mode optical fiber. The analysis of a Sagnac fiber optic interferometer is an example of this method application.

  16. Theoretical analysis of single molecule spectroscopy lineshapes of conjugated polymers

    NASA Astrophysics Data System (ADS)

    Devi, Murali

    Conjugated Polymers(CPs) exhibit a wide range of highly tunable optical properties. Quantitative and detailed understanding of the nature of excitons responsible for such a rich optical behavior has significant implications for better utilization of CPs for more efficient plastic solar cells and other novel optoelectronic devices. In general, samples of CPs are plagued with substantial inhomogeneous broadening due to various sources of disorder. Single molecule emission spectroscopy (SMES) offers a unique opportunity to investigate the energetics and dynamics of excitons and their interactions with phonon modes. The major subject of the present thesis is to analyze and understand room temperature SMES lineshapes for a particular CP, called poly(2,5-di-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (DEH-PPV). A minimal quantum mechanical model of a two-level system coupled to a Brownian oscillator bath is utilized. The main objective is to identify the set of model parameters best fitting a SMES lineshape for each of about 200 samples of DEH-PPV, from which new insight into the nature of exciton-bath coupling can be gained. This project also entails developing a reliable computational methodology for quantum mechanical modeling of spectral lineshapes in general. Well-known optimization techniques such as gradient descent, genetic algorithms, and heuristic searches have been tested, employing an L2 measure between theoretical and experimental lineshapes for guiding the optimization. However, all of these tend to result in theoretical lineshapes qualitatively different from experimental ones. This is attributed to the ruggedness of the parameter space and inadequateness of the L2 measure. On the other hand, when the dynamic reduction of the original parameter space to a 2-parameter space through feature searching and visualization of the search space paths using directed acyclic graphs(DAGs), the qualitative nature of the fitting improved significantly. For a more

  17. [Analysis on the accuracy of simple selection method of Fengshi (GB 31)].

    PubMed

    Li, Zhixing; Zhang, Haihua; Li, Suhe

    2015-12-01

    To explore the accuracy of simple selection method of Fengshi (GB 31). Through the study of the ancient and modern data,the analysis and integration of the acupuncture books,the comparison of the locations of Fengshi (GB 31) by doctors from all dynasties and the integration of modern anatomia, the modern simple selection method of Fengshi (GB 31) is definite, which is the same as the traditional way. It is believed that the simple selec tion method is in accord with the human-oriented thought of TCM. Treatment by acupoints should be based on the emerging nature and the individual difference of patients. Also, it is proposed that Fengshi (GB 31) should be located through the integration between the simple method and body surface anatomical mark.

  18. Theoretical limits on detection and analysis of small earthquakes

    NASA Astrophysics Data System (ADS)

    Kwiatek, Grzegorz; Ben-Zion, Yehuda

    2016-08-01

    We investigate theoretical limits on detection and reliable estimates of source characteristics of small earthquakes using synthetic seismograms for shear/tensile dislocations on kinematic circular ruptures and observed seismic noise and properties of several acquisition systems (instrument response, sampling rate). Simulated source time functions for shear/tensile dislocation events with different magnitudes, static stress drops, and rupture velocities provide estimates for the amplitude and frequency content of P and S phases at various observation angles. The source time functions are convolved with a Green's function for a homogenous solid assuming given P, S wave velocities and attenuation coefficients and a given instrument response. The synthetic waveforms are superposed with average levels of the observed ambient seismic noise up to 1 kHz. The combined seismograms are used to calculate signal-to-noise ratios and expected frequency content of P and S phases at various locations. The synthetic simulations of signal-to-noise ratio reproduce observed ratios extracted from several well-recorded data sets. The results provide guidelines on detection of small events in various geological environments, along with information relevant to reliable analyses of earthquake source properties.

  19. Genome mapping by random anchoring: A discrete theoretical analysis

    NASA Astrophysics Data System (ADS)

    Zhang, M. Q.; Marr, T. G.

    1993-11-01

    As a part of the international human genome project, large-scale genomic maps of human and other model organisms are being generated. More recently, mapping using various anchoring (as opposed to the traditional "fingerprinting") strategies have been proposed based largely on mathematical models. In all of the theoretical work dealing with anchoring, an anchor has been idealized as a point on a continuous, infinite-length genome. In general, it is not desirable to make these assumptions, since in practice they may be violated under a variety of actual biological situations. Here we analyze a discrete model that can be used to predict the expected progress made when mapping by random anchoring. By virtue of keeping all three length scales (genome length, clone length, and probe length) finite, our results for the random anchoring strategy are derived in full generality, which contain previous results as special cases and hence can have broad application for planning mapping experiments or assessing the accuracy of the continuum models. Finally, we pose a challenging nonrandom anchoring model corresponding to a more efficient mapping scheme.

  20. A computational and theoretical analysis of falling frequency VLF emissions

    NASA Astrophysics Data System (ADS)

    Nunn, David; Omura, Yoshiharu

    2012-08-01

    Recently much progress has been made in the simulation and theoretical understanding of rising frequency triggered emissions and rising chorus. Both PIC and Vlasov VHS codes produce risers in the region downstream from the equator toward which the VLF waves are traveling. The VHS code only produces fallers or downward hooks with difficulty due to the coherent nature of wave particle interaction across the equator. With the VHS code we now confine the interaction region to be the region upstream from the equator, where inhomogeneity factor S is positive. This suppresses correlated wave particle interaction effects across the equator and the tendency of the code to trigger risers, and permits the formation of a proper falling tone generation region. The VHS code now easily and reproducibly triggers falling tones. The evolution of resonant particle current JE in space and time shows a generation point at -5224 km and the wavefield undergoes amplification of some 25 dB in traversing the nonlinear generation region. The current component parallel to wave magnetic field (JB) is positive, whereas it is negative for risers. The resonant particle trap shows an enhanced distribution function or `hill', whereas risers have a `hole'. According to recent theory (Omura et al., 2008, 2009) sweeping frequency is due primarily to the advective term. The nonlinear frequency shift term is now negative (˜-12 Hz) and the sweep rate of -800 Hz/s is approximately nonlinear frequency shift divided by TN, the transition time, of the order of a trapping time.

  1. Graph theoretical analysis of EEG functional connectivity during music perception.

    PubMed

    Wu, Junjie; Zhang, Junsong; Liu, Chu; Liu, Dongwei; Ding, Xiaojun; Zhou, Changle

    2012-11-05

    The present study evaluated the effect of music on large-scale structure of functional brain networks using graph theoretical concepts. While most studies on music perception used Western music as an acoustic stimulus, Guqin music, representative of Eastern music, was selected for this experiment to increase our knowledge of music perception. Electroencephalography (EEG) was recorded from non-musician volunteers in three conditions: Guqin music, noise and silence backgrounds. Phase coherence was calculated in the alpha band and between all pairs of EEG channels to construct correlation matrices. Each resulting matrix was converted into a weighted graph using a threshold, and two network measures: the clustering coefficient and characteristic path length were calculated. Music perception was found to display a higher level mean phase coherence. Over the whole range of thresholds, the clustering coefficient was larger while listening to music, whereas the path length was smaller. Networks in music background still had a shorter characteristic path length even after the correction for differences in mean synchronization level among background conditions. This topological change indicated a more optimal structure under music perception. Thus, prominent small-world properties are confirmed in functional brain networks. Furthermore, music perception shows an increase of functional connectivity and an enhancement of small-world network organizations.

  2. A game theoretic analysis of research data sharing

    PubMed Central

    Wiersma, Paulien H.; van Weerden, Anne; Schieving, Feike

    2015-01-01

    While reusing research data has evident benefits for the scientific community as a whole, decisions to archive and share these data are primarily made by individual researchers. In this paper we analyse, within a game theoretical framework, how sharing and reuse of research data affect individuals who share or do not share their datasets. We construct a model in which there is a cost associated with sharing datasets whereas reusing such sets implies a benefit. In our calculations, conflicting interests appear for researchers. Individual researchers are always better off not sharing and omitting the sharing cost, at the same time both sharing and not sharing researchers are better off if (almost) all researchers share. Namely, the more researchers share, the more benefit can be gained by the reuse of those datasets. We simulated several policy measures to increase benefits for researchers sharing or reusing datasets. Results point out that, although policies should be able to increase the rate of sharing researchers, and increased discoverability and dataset quality could partly compensate for costs, a better measure would be to directly lower the cost for sharing, or even turn it into a (citation-) benefit. Making data available would in that case become the most profitable, and therefore stable, strategy. This means researchers would willingly make their datasets available, and arguably in the best possible way to enable reuse. PMID:26401453

  3. Theoretical analysis of high-resolution digital mammography

    NASA Astrophysics Data System (ADS)

    Suryanarayanan, Sankararaman; Karellas, Andrew; Vedantham, Srinivasan; Sechopoulos, Ioannis

    2006-06-01

    The performance of a high-resolution charge coupled device-based full-field digital mammography imager was analysed using a mathematical framework based on an adaptation of cascaded linear systems theory described by other investigators. This work has been conducted in order to understand the impact of various design parameters on the physical performance characteristics of the imager. Specifically, the effect of pixel size, scintillator thickness and packing density, x-ray spectra, air kerma, dark current, charge integration time, and pixel fill-factor on the frequency dependent detective quantum efficiency was studied using a charge-coupled device as a reference platform. The imaging system was modelled as a series of physical processes with gain and spatial spreading. For each stage, the signal and noise power spectra were computed and propagated through the imaging chain as inputs to subsequent stages. Good agreement between experimental and theoretical predictions was obtained for various x-ray spectral conditions that were investigated. The modulation transfer function, MTF(f) and detective quantum efficiency DQE(f) characteristics obtained in this study are encouraging and comparable to other digital mammography systems. The results of this study strongly suggest the feasibility of large area scintillator-based digital mammography imagers with pixel sizes below 100 µm.

  4. Graph theoretic analysis of protein interaction networks of eukaryotes

    NASA Astrophysics Data System (ADS)

    Goh, K.-I.; Kahng, B.; Kim, D.

    2005-11-01

    Owing to the recent progress in high-throughput experimental techniques, the datasets of large-scale protein interactions of prototypical multicellular species, the nematode worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster, have been assayed. The datasets are obtained mainly by using the yeast hybrid method, which contains false-positive and false-negative simultaneously. Accordingly, while it is desirable to test such datasets through further wet experiments, here we invoke recent developed network theory to test such high-throughput datasets in a simple way. Based on the fact that the key biological processes indispensable to maintaining life are conserved across eukaryotic species, and the comparison of structural properties of the protein interaction networks (PINs) of the two species with those of the yeast PIN, we find that while the worm and yeast PIN datasets exhibit similar structural properties, the current fly dataset, though most comprehensively screened ever, does not reflect generic structural properties correctly as it is. The modularity is suppressed and the connectivity correlation is lacking. Addition of interologs to the current fly dataset increases the modularity and enhances the occurrence of triangular motifs as well. The connectivity correlation function of the fly, however, remains distinct under such interolog additions, for which we present a possible scenario through an in silico modeling.

  5. Graph theoretical analysis of resting magnetoencephalographic functional connectivity networks

    PubMed Central

    Rutter, Lindsay; Nadar, Sreenivasan R.; Holroyd, Tom; Carver, Frederick W.; Apud, Jose; Weinberger, Daniel R.; Coppola, Richard

    2013-01-01

    Complex networks have been observed to comprise small-world properties, believed to represent an optimal organization of local specialization and global integration of information processing at reduced wiring cost. Here, we applied magnitude squared coherence to resting magnetoencephalographic time series in reconstructed source space, acquired from controls and patients with schizophrenia, and generated frequency-dependent adjacency matrices modeling functional connectivity between virtual channels. After configuring undirected binary and weighted graphs, we found that all human networks demonstrated highly localized clustering and short characteristic path lengths. The most conservatively thresholded networks showed efficient wiring, with topographical distance between connected vertices amounting to one-third as observed in surrogate randomized topologies. Nodal degrees of the human networks conformed to a heavy-tailed exponentially truncated power-law, compatible with the existence of hubs, which included theta and alpha bilateral cerebellar tonsil, beta and gamma bilateral posterior cingulate, and bilateral thalamus across all frequencies. We conclude that all networks showed small-worldness, minimal physical connection distance, and skewed degree distributions characteristic of physically-embedded networks, and that these calculations derived from graph theoretical mathematics did not quantifiably distinguish between subject populations, independent of bandwidth. However, post-hoc measurements of edge computations at the scale of the individual vertex revealed trends of reduced gamma connectivity across the posterior medial parietal cortex in patients, an observation consistent with our prior resting activation study that found significant reduction of synthetic aperture magnetometry gamma power across similar regions. The basis of these small differences remains unclear. PMID:23874288

  6. Accuracy Analysis of a Box-wing Theoretical SRP Model

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoya; Hu, Xiaogong; Zhao, Qunhe; Guo, Rui

    2016-07-01

    For Beidou satellite navigation system (BDS) a high accuracy SRP model is necessary for high precise applications especially with Global BDS establishment in future. The BDS accuracy for broadcast ephemeris need be improved. So, a box-wing theoretical SRP model with fine structure and adding conical shadow factor of earth and moon were established. We verified this SRP model by the GPS Block IIF satellites. The calculation was done with the data of PRN 1, 24, 25, 27 satellites. The results show that the physical SRP model for POD and forecast for GPS IIF satellite has higher accuracy with respect to Bern empirical model. The 3D-RMS of orbit is about 20 centimeters. The POD accuracy for both models is similar but the prediction accuracy with the physical SRP model is more than doubled. We tested 1-day 3-day and 7-day orbit prediction. The longer is the prediction arc length, the more significant is the improvement. The orbit prediction accuracy with the physical SRP model for 1-day, 3-day and 7-day arc length are 0.4m, 2.0m, 10.0m respectively. But they are 0.9m, 5.5m and 30m with Bern empirical model respectively. We apply this means to the BDS and give out a SRP model for Beidou satellites. Then we test and verify the model with Beidou data of one month only for test. Initial results show the model is good but needs more data for verification and improvement. The orbit residual RMS is similar to that with our empirical force model which only estimate the force for along track, across track direction and y-bias. But the orbit overlap and SLR observation evaluation show some improvement. The remaining empirical force is reduced significantly for present Beidou constellation.

  7. Theoretical performance analysis for CMOS based high resolution detectors.

    PubMed

    Jain, Amit; Bednarek, Daniel R; Rudin, Stephen

    2013-03-06

    High resolution imaging capabilities are essential for accurately guiding successful endovascular interventional procedures. Present x-ray imaging detectors are not always adequate due to their inherent limitations. The newly-developed high-resolution micro-angiographic fluoroscope (MAF-CCD) detector has demonstrated excellent clinical image quality; however, further improvement in performance and physical design may be possible using CMOS sensors. We have thus calculated the theoretical performance of two proposed CMOS detectors which may be used as a successor to the MAF. The proposed detectors have a 300 μm thick HL-type CsI phosphor, a 50 μm-pixel CMOS sensor with and without a variable gain light image intensifier (LII), and are designated MAF-CMOS-LII and MAF-CMOS, respectively. For the performance evaluation, linear cascade modeling was used. The detector imaging chains were divided into individual stages characterized by one of the basic processes (quantum gain, binomial selection, stochastic and deterministic blurring, additive noise). Ranges of readout noise and exposure were used to calculate the detectors' MTF and DQE. The MAF-CMOS showed slightly better MTF than the MAF-CMOS-LII, but the MAF-CMOS-LII showed far better DQE, especially for lower exposures. The proposed detectors can have improved MTF and DQE compared with the present high resolution MAF detector. The performance of the MAF-CMOS is excellent for the angiography exposure range; however it is limited at fluoroscopic levels due to additive instrumentation noise. The MAF-CMOS-LII, having the advantage of the variable LII gain, can overcome the noise limitation and hence may perform exceptionally for the full range of required exposures; however, it is more complex and hence more expensive.

  8. An Optimality-Theoretic Analysis of Codas in Brazilian Portuguese

    ERIC Educational Resources Information Center

    Goodin-Mayeda, C. Elizabeth

    2015-01-01

    Brazilian Portuguese allows only /s, N, l, r/ syllable finally, and of these, only /s/ is realized faithfully (as well as /r/ for some speakers). In order to avoid unacceptable codas, dialects of Brazilian Portuguese employ such strategies as epenthesis, nasal absorption, debucalization, and gliding. The current analysis argues that codas in…

  9. Sequential Phenomena in Psychophysical Judgments: A Theoretical Analysis

    NASA Technical Reports Server (NTRS)

    Atkinson, R. C.; Carterette, E. C.; Kinchla, R. A.

    1962-01-01

    This paper deals with an analysis of psychophysical detection experiments designed to assess the limit of a human observer's level of sensitivity. A mathematical theory or the detection process is introduced that, in contrast to previous theories, provides an analysis of the sequential effects observed in psychophysical data. Two variations of the detection task are considered: information feedback and no-information feedback. In the feedback situation the subject is given information concerning the correctness of his responses, whereas in the no-feedback situation he is not. Data from a visual detection experiment with no-information feedback, and from an auditory detection experiment with information feedback are analyzed in terms of the theory. Finally, some general results are derived concerning the relationship between performance in the feedback situation and the no-feedback situation.

  10. Theoretical Innovations in Combustion Stability Research: Integrated Analysis and Computation

    DTIC Science & Technology

    2011-04-14

    presentation [2] has been made at a national conference of this subject. b.2-Thermomechanics of reactive gases Transient, spatially...Integrated Analysis and Computation 5a. CONTRACT NUMBER FA9550-10-C-0088 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) David Kassoy...KISS and JPL personnel. 15. SUBJECT TERMS Combustion, Thermomechanics, Turbulent Reacting Flow, Supercritical Gases , Rocket Engine Stability 16

  11. A Simple Card Trick: Teaching Qualitative Data Analysis Using a Deck of Playing Cards

    ERIC Educational Resources Information Center

    Waite, Duncan

    2011-01-01

    Yet today, despite recent welcome additions, relatively little is written about teaching qualitative research. Why is that? This article reports out a relatively simple, yet appealing, pedagogical move, a lesson the author uses to teach qualitative data analysis. Data sorting and categorization, the use of tacit and explicit theory in data…

  12. A Simple Gauss-Newton Procedure for Covariance Structure Analysis with High-Level Computer Languages.

    ERIC Educational Resources Information Center

    Cudeck, Robert; And Others

    1993-01-01

    An implementation of the Gauss-Newton algorithm for the analysis of covariance structure that is specifically adapted for high-level computer languages is reviewed. This simple method for estimating structural equation models is useful for a variety of standard models, as is illustrated. (SLD)

  13. Global Study of the Simple Pendulum by the Homotopy Analysis Method

    ERIC Educational Resources Information Center

    Bel, A.; Reartes, W.; Torresi, A.

    2012-01-01

    Techniques are developed to find all periodic solutions in the simple pendulum by means of the homotopy analysis method (HAM). This involves the solution of the equations of motion in two different coordinate representations. Expressions are obtained for the cycles and periods of oscillations with a high degree of accuracy in the whole range of…

  14. Thermal analysis of a simple-cycle gas turbine in biogas power generation

    SciTech Connect

    Yomogida, D.E.; Thinh, Ngo Dinh

    1995-09-01

    This paper investigates the technical feasibility of utilizing small simple-cycle gas turbines (25 kW to 125 kW) for biogas power generation through thermal analysis. A computer code, GTPower, was developed to evaluate the performance of small simple-cycle gas turbines specifically for biogas combustion. The 125 KW Solar Gas Turbine (Tital series) has been selected as the base case gas turbine for biogas combustion. After its design parameters and typical operating conditions were entered into GTPower for analysis, GTPower outputted expected values for the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work. For a sensitivity analysis, the GTPower Model outputted the thermal efficiency and specific work profiles for various operating conditions encountered in biogas combustion. These results will assist future research projects in determining the type of combustion device most suitable for biogas power generation.

  15. Graph theoretical analysis of complex networks in the brain.

    PubMed

    Stam, Cornelis J; Reijneveld, Jaap C

    2007-07-05

    Since the discovery of small-world and scale-free networks the study of complex systems from a network perspective has taken an enormous flight. In recent years many important properties of complex networks have been delineated. In particular, significant progress has been made in understanding the relationship between the structural properties of networks and the nature of dynamics taking place on these networks. For instance, the 'synchronizability' of complex networks of coupled oscillators can be determined by graph spectral analysis. These developments in the theory of complex networks have inspired new applications in the field of neuroscience. Graph analysis has been used in the study of models of neural networks, anatomical connectivity, and functional connectivity based upon fMRI, EEG and MEG. These studies suggest that the human brain can be modelled as a complex network, and may have a small-world structure both at the level of anatomical as well as functional connectivity. This small-world structure is hypothesized to reflect an optimal situation associated with rapid synchronization and information transfer, minimal wiring costs, as well as a balance between local processing and global integration. The topological structure of functional networks is probably restrained by genetic and anatomical factors, but can be modified during tasks. There is also increasing evidence that various types of brain disease such as Alzheimer's disease, schizophrenia, brain tumours and epilepsy may be associated with deviations of the functional network topology from the optimal small-world pattern.

  16. A Theoretical Analysis of Thermal Radiation from Neutron Stars

    NASA Technical Reports Server (NTRS)

    Applegate, James H.

    1993-01-01

    As soon as it was realized that the direct URCA process is allowed by many modern nuclear equation of state, an analysis of its effect on the cooling of neutron stars was undertaken. A primary study showed that the occurrence of the direct URCA process makes the surface temperature of a neutron star suddenly drop by almost an order of magnitude when the cold wave from the core reaches the surface when the star is a few years old. The results of this study are published in Page and Applegate. As a work in progress, we are presently extending the above work. Improved expressions for the effect of nucleon pairing on the neutrino emissivity and specific heat are now available, and we have incorporated them in a recalculation of rate of the direct URCA process.

  17. Theoretic analysis on electric conductance of nano-wire transistors

    NASA Astrophysics Data System (ADS)

    Tsai, N.-C.; Chiang, Y.-R.; Hsu, S.-L.

    2010-01-01

    By employing the commercial software nanoMos and Vienna ab Initio Simulation Package ( VASP), the performance of nano-wire field-effect transistors is investigated. In this paper, the Density-Gradient Model (DG Model) is used to describe the carrier transport behavior of the nano-wire transistor under quantum effects. The analysis of the drain current with respect to channel length, body dielectric constant and gate contact work function is presented. In addition, Fermi energy and DOS (Density of State) are introduced to explore the relative stability of carrier transport and electrical conductance for the silicon crystal with dopants. Finally, how the roughness of the surface of the silicon-based crystal is affected by dopants and their allocation can be illuminated by a few broken bonds between atoms near the skin of the crystal.

  18. Theoretical analysis of the density within an orbiting molecular shield

    NASA Technical Reports Server (NTRS)

    Hueser, J. E.; Brock, F. J.

    1976-01-01

    An analytical model based on the kinetic theory of a drifting Maxwellian gas is used to determine the nonequilibrium molecular density distribution within a hemispherical shell open aft with its axis parallel to its velocity. Separate numerical results are presented for the primary and secondary density distribution components due to the drifting Maxwellian gas for speed ratios between 2.5 and 10. An analysis is also made of the density component due to gas desorbed from the wall of the hemisphere, and numerical results are presented for the density distribution. It is shown that the adsorption process may be completely ignored. The results are applicable to orbital trajectories in any planet-atmosphere system and interplanetary transfer trajectories. Application to the earth's atmosphere is mentioned briefly.

  19. Theoretical analysis of the 2D thermal cloaking problem

    NASA Astrophysics Data System (ADS)

    Alekseev, G. V.; Spivak, Yu E.; Yashchenko, E. N.

    2017-01-01

    Coefficient inverse problems for the model of heat scattering with variable coefficients arising when developing technologies of design of thermal cloaking devices are considered. By the optimization method, these problems are reduced to respective control problems. The material parameters (radial and azimuthal conductivities) of the inhomogeneous anisotropic medium, filling the thermal cloak, play the role of control. The model of heat scattering acts as a functional restriction. A unique solvability of direct heat scattering problem in the Sobolev space is proved and the new estimates of solutions are established. Using these results, the solvability of control problem is proved and the optimality system is derived. Based on analysis of optimality system, the stability estimates of optimal solutions are established and efficient numerical algorithm of solving thermal cloaking problems is proposed.

  20. Molecular magnetic properties of heteroporphyrins: a theoretical analysis.

    PubMed

    Campomanes, Pablo; Menéndez, María Isabel; Cárdenas-Jirón, Gloria Inés; Sordo, Tomás Luis

    2007-11-14

    B3LYP/6-31G(d) optimization of porphyrin, tetraphenylporphyrin and their 21,23-diheteroatom substituted derivatives with O, S, and Se heteroatoms was performed. A planar macrocycle was found in all cases except 21,23-dioxatetraphenylporphyrin which presents only slight deviations from planarity. A Bader analysis uncovers the presence of S-S and Se-Se interactions in the four corresponding heteroporphyrins, which appreciably distort the original unsubstituted macrocycles. In the minimum energy structures of heterotetraphenylporphyrins the four meso phenyl groups slant alternatively to right or left so that the two pairs of opposite phenyls present a staggered conformation. The pi current induced by a perpendicular magnetic field in porphyrin bifurcates across both types of pyrrole subunits but the presence of O, S and Se heteroatoms in 21,23-diheteroporphyrins causes a diminution of the current density through the inner section of the two heterorings and, consequently, the current path goes then through the outer section of these rings. The NICS values at the ring critical points of the heterorings are much larger (in absolute value) than those at the pyrrole ring critical points but appreciably smaller than that at the ring critical point of a pyrrole molecule. In agreement with experimental data the (1)H NMR present appreciable downfield shifts for the beta H atoms of the heterorings in the 21,23-heterosubstituted molecules.

  1. Theoretical and numerical analysis of the corneal air puff test

    NASA Astrophysics Data System (ADS)

    Simonini, Irene; Angelillo, Maurizio; Pandolfi, Anna

    2016-08-01

    Ocular analyzers are used in the current clinical practice to estimate, by means of a rapid air jet, the intraocular pressure and other eye's parameters. In this study, we model the biomechanical response of the human cornea to the dynamic test with two approaches. In the first approach, the corneal system undergoing the air puff test is regarded as a harmonic oscillator. In the second approach, we use patient-specific geometries and the finite element method to simulate the dynamic test on surgically treated corneas. In spite of the different levels of approximation, the qualitative response of the two models is very similar, and the most meaningful results of both models are not significantly affected by the inclusion of viscosity of the corneal material in the dynamic analysis. Finite element calculations reproduce the observed snap-through of the corneal shell, including two applanate configurations, and compare well with in vivo images provided by ocular analyzers, suggesting that the mechanical response of the cornea to the air puff test is actually driven only by the elasticity of the stromal tissue. These observations agree with the dynamic characteristics of the test, since the frequency of the air puff impulse is several orders of magnitude larger than the reciprocal of any reasonable relaxation time for the material, downplaying the role of viscosity during the fast snap-through phase.

  2. Spectral derivative analysis of solar spectroradiometric measurements: Theoretical basis

    NASA Astrophysics Data System (ADS)

    Hansell, R. A.; Tsay, S.-C.; Pantina, P.; Lewis, J. R.; Ji, Q.; Herman, J. R.

    2014-07-01

    Spectral derivative analysis, a commonly used tool in analytical spectroscopy, is described for studying cirrus clouds and aerosols using hyperspectral, remote sensing data. The methodology employs spectral measurements from the 2006 Biomass-burning Aerosols in Southeast Asia field study to demonstrate the approach. Spectral peaks associated with the first two derivatives of measured/modeled transmitted spectral fluxes are examined in terms of their shapes, magnitudes, and positions from 350 to 750 nm, where variability is largest. Differences in spectral features between media are mainly associated with particle size and imaginary term of the complex refractive index. Differences in derivative spectra permit cirrus to be conservatively detected at optical depths near the optical thin limit of ~0.03 and yield valuable insight into the composition and hygroscopic nature of aerosols. Biomass-burning smoke aerosols/cirrus generally exhibit positive/negative slopes, respectively, across the 500-700 nm spectral band. The effect of cirrus in combined media is to increase/decrease the slope as cloud optical thickness decreases/increases. For thick cirrus, the slope tends to 0. An algorithm is also presented which employs a two model fit of derivative spectra for determining relative contributions of aerosols/clouds to measured data, thus enabling the optical thickness of the media to be partitioned. For the cases examined, aerosols/clouds explain ~83%/17% of the spectral signatures, respectively, yielding a mean cirrus cloud optical thickness of 0.08 ± 0.03, which compared reasonably well with those retrieved from a collocated Micropulse Lidar Network Instrument (0.09 ± 0.04). This method permits extracting the maximum informational content from hyperspectral data for atmospheric remote sensing applications.

  3. Theoretical analysis of oxygen supply to contracted skeletal muscle.

    PubMed

    Groebe, K; Thews, G

    1986-01-01

    Honig and collaborators reported striking contradictions in current understanding of O2 supply to working skeletal muscle. Therefore we re-examined the problem by means of a new composite computer simulation. As inclusion of erythrocytic O2 desaturation and oxygen transport and consumption inside the muscle cell into a single model would entail immense numerical difficulties, we broke up the whole process into its several components: O2 desaturation of erythrocytes O2 transport and consumption in muscle fiber capillary transit time characterizing the period of contact between red cell and muscle fiber. "Erythrocyte model" as well as "muscle fiber model" both consist of a central core cylinder surrounded by a concentric diffusion layer representing the extracellular resistance to O2 diffusion (Fig. 1). Resistance layers in both models are to be conceived of as one and the same anatomical structure--even though in each model their shape is adapted to the respective geometry. By means of this overlap region a spatial connexion between both is given, whereas temporal coherence governing O2 fluxes and red cell spacing is derived from capillary transit time. Analysis of individual components is outlined as follows: Assuming axial symmetry of the problem a numerical algorithm was employed to solve the parabolic system of partial differential equations describing red cell O2 desaturation. Hb-O2 reaction kinetics, free and facilitated O2 diffusion in axial and radial directions, and red cell movement in capillary were considered. Resulting time courses of desaturation, which are considerably faster than the ones computed by Honig et al., are given in the following table (see also Fig. 3). (Formula: see text) Furthermore, we studied the respective importance of the several processes included in our model: Omission of longitudinal diffusion increased desaturation time by 15% to 23%, whereas effects of reaction kinetics and axial movement were 5% and 2% respectively. For time

  4. Theoretical analysis of droplet transition from Cassie to Wenzel state

    NASA Astrophysics Data System (ADS)

    Liu, Tian-Qing; Yan-Jie, Li; Xiang-Qin, Li; Wei, Sun

    2015-11-01

    Whether droplets transit from the Cassie to the Wenzel state (C-W) on a textured surface is the touchstone that the superhydrophobicity of the surface is still maintained. However, the C-W transition mechanism, especially the spontaneous transition of small droplets, is still not very clear to date. The interface free energy gradient of a small droplet is firstly proposed and derived as the driving force for its C-W evolution in this study based on the energy and gradient analysis. Then the physical and mathematical model of the C-W transition is found after the C-W driving force or transition pressure, the resistance, and the parameters of the meniscus beneath the droplet are formulated. The results show that the micro/nano structural parameters significantly affect the C-W driving force and resistance. The smaller the pillar diameter and pitch, the minor the C-W transition pressure, and the larger the resistance. Consequently, the C-W transition is difficult to be completed for the droplets on nano-textured surfaces. Meanwhile if the posts are too short, the front of the curved liquid-air interface below the droplet will touch the structural substrate easily even though the three phase contact line (TPCL) has not depinned. When the posts are high enough, the TPCL beneath the drop must move firstly before the meniscus can reach the substrate. As a result, the droplet on a textured surface with short pillars is easy to complete its C-W evolution. On the other hand, the smaller the droplet, the easier the C-W shift, since the transition pressure becomes larger, which well explains why an evaporating drop will collapse spontaneously from composite to Wenzel state. Besides, both intrinsic and advancing contact angles affect the C-W transition as well. The greater the two angles, the harder the C-W transition. In the end, the C-W transition parameters and the critical conditions measured in literatures are calculated and compared, and the calculations accord well with

  5. Quantitative Analysis of the Nanopore Translocation Dynamics of Simple Structured Polynucleotides

    PubMed Central

    Schink, Severin; Renner, Stephan; Alim, Karen; Arnaut, Vera; Simmel, Friedrich C.; Gerland, Ulrich

    2012-01-01

    Nanopore translocation experiments are increasingly applied to probe the secondary structures of RNA and DNA molecules. Here, we report two vital steps toward establishing nanopore translocation as a tool for the systematic and quantitative analysis of polynucleotide folding: 1), Using α-hemolysin pores and a diverse set of different DNA hairpins, we demonstrate that backward nanopore force spectroscopy is particularly well suited for quantitative analysis. In contrast to forward translocation from the vestibule side of the pore, backward translocation times do not appear to be significantly affected by pore-DNA interactions. 2), We develop and verify experimentally a versatile mesoscopic theoretical framework for the quantitative analysis of translocation experiments with structured polynucleotides. The underlying model is based on sequence-dependent free energy landscapes constructed using the known thermodynamic parameters for polynucleotide basepairing. This approach limits the adjustable parameters to a small set of sequence-independent parameters. After parameter calibration, the theoretical model predicts the translocation dynamics of new sequences. These predictions can be leveraged to generate a baseline expectation even for more complicated structures where the assumptions underlying the one-dimensional free energy landscape may no longer be satisfied. Taken together, backward translocation through α-hemolysin pores combined with mesoscopic theoretical modeling is a promising approach for label-free single-molecule analysis of DNA and RNA folding. PMID:22225801

  6. ViSimpl: Multi-View Visual Analysis of Brain Simulation Data

    PubMed Central

    Galindo, Sergio E.; Toharia, Pablo; Robles, Oscar D.; Pastor, Luis

    2016-01-01

    After decades of independent morphological and functional brain research, a key point in neuroscience nowadays is to understand the combined relationships between the structure of the brain and its components and their dynamics on multiple scales, ranging from circuits of neurons at micro or mesoscale to brain regions at macroscale. With such a goal in mind, there is a vast amount of research focusing on modeling and simulating activity within neuronal structures, and these simulations generate large and complex datasets which have to be analyzed in order to gain the desired insight. In such context, this paper presents ViSimpl, which integrates a set of visualization and interaction tools that provide a semantic view of brain data with the aim of improving its analysis procedures. ViSimpl provides 3D particle-based rendering that allows visualizing simulation data with their associated spatial and temporal information, enhancing the knowledge extraction process. It also provides abstract representations of the time-varying magnitudes supporting different data aggregation and disaggregation operations and giving also focus and context clues. In addition, ViSimpl tools provide synchronized playback control of the simulation being analyzed. Finally, ViSimpl allows performing selection and filtering operations relying on an application called NeuroScheme. All these views are loosely coupled and can be used independently, but they can also work together as linked views, both in centralized and distributed computing environments, enhancing the data exploration and analysis procedures. PMID:27774062

  7. Modeling and Theoretical Analysis of On-Chip Phase-Sensitive Amplifiers

    DTIC Science & Technology

    2016-04-19

    SECURITY CLASSIFICATION OF: We performed a theoretical study of phase-sentisitive amplification in semiconductor optical amplifiers (SOAs), so as to...wavelength mixing in semiconductor optical amplifiers (SOAs) based on coupled-mode equations. The proposed model applies to all kinds of SOA...Unlimited UU UU UU UU 19-04-2016 1-Jun-2014 30-Nov-2015 Final Report: Modeling and Theoretical Analysis of On-Chip Phase-Sensitive Amplifiers The

  8. Theoretical analysis of cell separation based on cell surface marker density.

    PubMed

    Chalmers, J J; Zborowski, M; Moore, L; Mandal, S; Fang, B B; Sun, L

    1998-07-05

    A theoretical analysis was performed to determine the number of fractions a multidisperse, immunomagnetically labeled cell population can be separated into based on the surface marker (antigen) density. A number of assumptions were made in this analysis: that there is a proportionality between the number of surface markers on the cell surface and the number of immunomagnetic labels bound; that this surface marker density is independent of the cell diameter; and that there is only the presence of magnetic and drag forces acting on the cell. Due to the normal distribution of cell diameters, a "randomizing" effect enters into the analysis, and an analogy between the "theoretical plate" analysis of distillation, adsorption, and chromatography can be made. Using the experimentally determined, normal distribution of cell diameters for human lymphocytes and a breast cancer cell line, and fluorescent activated cell screening data of specific surface marker distributions, examples of theoretical plate calculations were made and discussed.

  9. A simple polyol-free synthesis route to Gd2O3 nanoparticles for MRI applications: an experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Ahrén, Maria; Selegård, Linnéa; Söderlind, Fredrik; Linares, Mathieu; Kauczor, Joanna; Norman, Patrick; Käll, Per-Olov; Uvdal, Kajsa

    2012-08-01

    Chelated gadolinium ions, e.g., Gd-DTPA, are today used clinically as contrast agents for magnetic resonance imaging (MRI). An attractive alternative contrast agent is composed of gadolinium oxide nanoparticles as they have shown to provide enhanced contrast and, in principle, more straightforward molecular capping possibilities. In this study, we report a new, simple, and polyol-free way of synthesizing 4-5-nm-sized Gd2O3 nanoparticles at room temperature, with high stability and water solubility. The nanoparticles induce high-proton relaxivity compared to Gd-DTPA showing r 1 and r 2 values almost as high as those for free Gd3+ ions in water. The Gd2O3 nanoparticles are capped with acetate and carbonate groups, as shown with infrared spectroscopy, near-edge X-ray absorption spectroscopy, X-ray photoelectron spectroscopy and combined thermogravimetric and mass spectroscopy analysis. Interpretation of infrared spectroscopy data is corroborated by extensive quantum chemical calculations. This nanomaterial is easily prepared and has promising properties to function as a core in a future contrast agent for MRI.

  10. Chapter 2. General theoretical perspectives of narrative analysis of substance use-related dependency.

    PubMed

    Larsson, Sam; Lilja, John; von Braun, Therese; Sjöblom, Yvonne

    2013-11-01

    This chapter provides a short introduction to, and an overview for, using narrative analysis in the understanding of the use and misuse of alcohol and drugs. Important theoretical and methodological dimensions are discussed. Some tentative conclusions, limitations, and unresolved critical issues concerning the use of narrative research methods in the analysis of substance use-related dependency problems are also presented.

  11. Study on the Theoretical Foundation of Business English Curriculum Design Based on ESP and Needs Analysis

    ERIC Educational Resources Information Center

    Zhu, Wenzhong; Liu, Dan

    2014-01-01

    Based on a review of the literature on ESP and needs analysis, this paper is intended to offer some theoretical supports and inspirations for BE instructors to develop BE curricula for business contexts. It discusses how the theory of need analysis can be used in Business English curriculum design, and proposes some principles of BE curriculum…

  12. A Theoretical Analysis of Potential Extinction Properties of Behavior-Specific Manual Restraint

    ERIC Educational Resources Information Center

    Cipani, Ennio; Thomas, Melvin; Martin, Daniel

    2007-01-01

    This paper will examine possible extinction properties of behavior-specific manual restraint. It will analyze the possibility of extinction being produced via restraint with respect to the target behavior's possible environmental functions. The theoretical analysis will involve the analysis of behavioral properties of restraint during two temporal…

  13. Theoretical analysis of the particle gradient distribution in centrifugal field during solidification

    SciTech Connect

    Liu, Q.; Jiao, Y.; Yang, Y.; Hu, Z.

    1996-12-01

    A theoretical analysis is presented to obtain gradient distribution of particles in centrifugal field, by which the particle distribution in gradient composite can be predicted. Particle movement in liquid is described and gradient distribution of particles in composite is calculated in a centrifugal field during the solidification. The factors which affect the particle distribution and its gradient are discussed in detail. The theoretical analysis indicated that a composite zone and a blank zone exist in gradient composite, which can be controlled to the outside or inside of the tubular composite by the density difference of particle and liquid metal. The comparison of the SiC particle distribution in Al matrix composite produced by centrifugal casting between the theory model and the experiment denotes that the theoretical analysis is reasonable.

  14. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    SciTech Connect

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-17

    We demonstrate that a non-perturbative framework for the treatment of the excitations of single walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. As a result, we test this theory explicitly on the data reported in [NanoLetters 5, 2314 (2005)] and [Phys. Rev. B 82, 195424 (2010)] and so demonstrate the method works over a wide range of reported excitonic spectra.

  15. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    DOE PAGES

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-17

    We demonstrate that a non-perturbative framework for the treatment of the excitations of single walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. Asmore » a result, we test this theory explicitly on the data reported in [NanoLetters 5, 2314 (2005)] and [Phys. Rev. B 82, 195424 (2010)] and so demonstrate the method works over a wide range of reported excitonic spectra.« less

  16. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    NASA Astrophysics Data System (ADS)

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-01

    We demonstrate that a nonperturbative framework for the treatment of the excitations of single-walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. We test this theory explicitly on the data reported by Dukovic et al. [Nano Lett. 5, 2314 (2005), 10.1021/nl0518122] and Sfeir et al. [Phys. Rev. B 82, 195424 (2010), 10.1103/PhysRevB.82.195424] and so demonstrate the method works over a wide range of reported excitonic spectra.

  17. Simple dual-spotting procedure enhances nLC-MALDI MS/MS analysis of digests with less specific enzymes.

    PubMed

    Baeumlisberger, Dominic; Rohmer, Marion; Arrey, Tabiwang N; Mueller, Benjamin F; Beckhaus, Tobias; Bahr, Ute; Barka, Guenes; Karas, Michael

    2011-06-03

    The beneficial effect of high mass accuracy in mass spectrometry is especially pronounced when using less specific enzymes as the number of theoretically possible peptides increases dramatically without any cleavage specificity defined. Together with a preceding chromatographic separation, high-resolution mass spectrometers such as the MALDI-LTQ-Orbitrap are therefore well suited for the analysis of protein digests with less specific enzymes. A combination with fast, automated, and informative MALDI-TOF/TOF analysis has already been shown to yield increased total peptide and protein identifications. Here, a simple method for nLC separation and subsequent alternating spotting on two targets for both a MALDI-LTQ-Orbitrap and a MALDI-TOF/TOF instrument is introduced. This allows for simultaneous measurements on both instruments and subsequent combination of both data sets by an in-house written software tool. The performance of this procedure was evaluated using a mixture of four standard proteins digested with elastase. Three replicate runs were examined concerning repeatability and the total information received from both instruments. A cytosolic extract of C. glutamicum was used to demonstrate the applicability to more complex samples. Database search results showed that an additional 32.3% of identified peptides were found using combined data sets in comparison to MALDI-TOF/TOF data sets.

  18. Simple imputation methods versus direct likelihood analysis for missing item scores in multilevel educational data.

    PubMed

    Kadengye, Damazo T; Cools, Wilfried; Ceulemans, Eva; Van den Noortgate, Wim

    2012-06-01

    Missing data, such as item responses in multilevel data, are ubiquitous in educational research settings. Researchers in the item response theory (IRT) context have shown that ignoring such missing data can create problems in the estimation of the IRT model parameters. Consequently, several imputation methods for dealing with missing item data have been proposed and shown to be effective when applied with traditional IRT models. Additionally, a nonimputation direct likelihood analysis has been shown to be an effective tool for handling missing observations in clustered data settings. This study investigates the performance of six simple imputation methods, which have been found to be useful in other IRT contexts, versus a direct likelihood analysis, in multilevel data from educational settings. Multilevel item response data were simulated on the basis of two empirical data sets, and some of the item scores were deleted, such that they were missing either completely at random or simply at random. An explanatory IRT model was used for modeling the complete, incomplete, and imputed data sets. We showed that direct likelihood analysis of the incomplete data sets produced unbiased parameter estimates that were comparable to those from a complete data analysis. Multiple-imputation approaches of the two-way mean and corrected item mean substitution methods displayed varying degrees of effectiveness in imputing data that in turn could produce unbiased parameter estimates. The simple random imputation, adjusted random imputation, item means substitution, and regression imputation methods seemed to be less effective in imputing missing item scores in multilevel data settings.

  19. Simple Machines Made Simple.

    ERIC Educational Resources Information Center

    St. Andre, Ralph E.

    Simple machines have become a lost point of study in elementary schools as teachers continue to have more material to cover. This manual provides hands-on, cooperative learning activities for grades three through eight concerning the six simple machines: wheel and axle, inclined plane, screw, pulley, wedge, and lever. Most activities can be…

  20. A Theoretical Analysis of Social Interactions in Computer-based Learning Environments: Evidence for Reciprocal Understandings.

    ERIC Educational Resources Information Center

    Jarvela, Sanna; Bonk, Curtis Jay; Lehtinen, Erno; Lehti, Sirpa

    1999-01-01

    Presents a theoretical and empirical analysis of social interactions in computer-based learning environments. Explores technology use to support reciprocal understanding between teachers and students based on three technology-based learning environments in Finland and the United States, and discusses situated learning, cognitive apprenticeships,…

  1. Forming Future Specialists' Valeological Competency: Theoretical Analysis of Domestic and Foreign Scholars' Views

    ERIC Educational Resources Information Center

    Maksymchuk, Borys

    2016-01-01

    The article deals with the analysis of theoretical and methodical principles of forming students' valeological competency in the process of physical education in higher pedagogical education institutions in domestic and foreign scientific literature. It has been defined that one of the most prominent factors in future teachers' training for…

  2. Security Analysis of Selected AMI Failure Scenarios Using Agent Based Game Theoretic Simulation

    SciTech Connect

    Abercrombie, Robert K; Schlicher, Bob G; Sheldon, Frederick T

    2014-01-01

    Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. We concentrated our analysis on the Advanced Metering Infrastructure (AMI) functional domain which the National Electric Sector Cyber security Organization Resource (NESCOR) working group has currently documented 29 failure scenarios. The strategy for the game was developed by analyzing five electric sector representative failure scenarios contained in the AMI functional domain. From these five selected scenarios, we characterize them into three specific threat categories affecting confidentiality, integrity and availability (CIA). The analysis using our ABGT simulation demonstrates how to model the AMI functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the AMI network with respect to CIA.

  3. A simple, objective analysis scheme for scatterometer data. [Seasat A satellite observation of wind over ocean

    NASA Technical Reports Server (NTRS)

    Levy, G.; Brown, R. A.

    1986-01-01

    A simple economical objective analysis scheme is devised and tested on real scatterometer data. It is designed to treat dense data such as those of the Seasat A Satellite Scatterometer (SASS) for individual or multiple passes, and preserves subsynoptic scale features. Errors are evaluated with the aid of sampling ('bootstrap') statistical methods. In addition, sensitivity tests have been performed which establish qualitative confidence in calculated fields of divergence and vorticity. The SASS wind algorithm could be improved; however, the data at this point are limited by instrument errors rather than analysis errors. The analysis error is typically negligible in comparison with the instrument error, but amounts to 30 percent of the instrument error in areas of strong wind shear. The scheme is very economical, and thus suitable for large volumes of dense data such as SASS data.

  4. Simple sequence repeat-based association analysis of fruit traits in eggplant (Solanum melongena).

    PubMed

    Ge, H Y; Liu, Y; Zhang, J; Han, H Q; Li, H Z; Shao, W T; Chen, H Y

    2013-11-18

    Association mapping based on linkage disequilibrium (LD) provides a promising tool to identify quantitative trait loci (QTLs) in plant resources. A total of 141 eggplant (Solanum melongena L.) accessions were selected to detect simple sequence repeat (SSR) markers associated with nine fruit traits. Population structure analysis was performed with 105 SSR markers, which revealed that two subgroups were present in this population. LD analysis exhibited an extensive long-range LD of approximately 11 cM. A total of 49 marker associations related to eight phenotypic traits were identified to involve 24 different markers, although no association was found with the trait of fruit glossiness. To our knowledge, this is the 1st approach to use a genome-wide association study in eggplant with SSR markers. These results suggest that the association analysis approach could be a useful alternative to traditional linkage mapping to detect putative QTLs in eggplant.

  5. A Simple Cost-Effective Framework for iPhone Forensic Analysis

    NASA Astrophysics Data System (ADS)

    Husain, Mohammad Iftekhar; Baggili, Ibrahim; Sridhar, Ramalingam

    Apple iPhone has made significant impact on the society both as a handheld computing device and as a cellular phone. Due to the unique hardware system as well as storage structure, iPhone has already attracted the forensic community in digital investigation of the device. Currently available commercial products and methodologies for iPhone forensics are somewhat expensive, complex and often require additional hardware for analysis. Some products are not robust and often fail to extract optimal evidence without modifying the iPhone firmware which makes the analysis questionable in legal platforms. In this paper, we present a simple and inexpensive framework (iFF) for iPhone forensic analysis. Through experimental results using real device, we have shown the effectiveness of this framework in extracting digital evidence from an iPhone.

  6. The theoretical analysis of an instrument for linear and angular displacements of the steered wheel measuring

    NASA Astrophysics Data System (ADS)

    Wach, K.

    2016-09-01

    In the paper the theoretical analysis of the measuring instrument for determination of translation and rotation of the stub axle with the steered wheel against car body was presented. The instrument is made of nine links with elongation sensors embedded in it. One of several possible structures of instrument of this kind was presented. Basing on solution of the geometrical constraints system of equations of the device, the numerical analysis of the measurement accuracy was conducted.

  7. In- silico exploration of thirty alphavirus genomes for analysis of the simple sequence repeats

    PubMed Central

    Alam, Chaudhary Mashhood; Singh, Avadhesh Kumar; Sharfuddin, Choudhary; Ali, Safdar

    2014-01-01

    The compilation of simple sequence repeats (SSRs) in viruses and its analysis with reference to incidence, distribution and variation would be instrumental in understanding the functional and evolutionary aspects of repeat sequences. Present study encompasses the analysis of SSRs across 30 species of alphaviruses. The full length genome sequences, assessed from NCBI were used for extraction and analysis of repeat sequences using IMEx software. The repeats of different motif sizes (mono- to penta-nucleotide) observed therein exhibited variable incidence across the species. Expectedly, mononucleotide A/T was the most prevalent followed by dinucleotide AG/GA and trinucleotide AAG/GAA in these genomes. The conversion of SSRs to imperfect microsatellite or compound microsatellite (cSSR) is low. cSSR, primarily constituted by variant motifs accounted for up to 12.5% of the SSRs. Interestingly, seven species lacked cSSR in their genomes. However, the SSR and cSSR are predominantly localized to the coding region ORFs for non structural protein and structural proteins. The relative frequencies of different classes of simple and compound microsatellites within and across genomes have been highlighted. PMID:25606453

  8. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography

    USGS Publications Warehouse

    Belisle, A.A.; Swineford, D.M.

    1988-01-01

    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  9. Enumeration and stability analysis of simple periodic orbits in β-Fermi Pasta Ulam lattice

    SciTech Connect

    Sonone, Rupali L. Jain, Sudhir R.

    2014-04-24

    We study the well-known one-dimensional problem of N particles with a nonlinear interaction. The special case of quadratic and quartic interaction potential among nearest neighbours is the β-Fermi-Pasta-Ulam model. We enumerate and classify the simple periodic orbits for this system and find the stability zones, employing Floquet theory. Such stability analysis is crucial to understand the transition of FPU lattice from recurrences to globally chaotic behavior, energy transport in lower dimensional system, dynamics of optical lattices and also its impact on shape parameter of bio-polymers such as DNA and RNA.

  10. Use of a simple enzymatic assay for cholesterol analysis in human bile.

    PubMed

    Fromm, H; Amin, P; Klein, H; Kupke, I

    1980-02-01

    An enzymatic technique for cholesterol analysis in serum was applied to human bile. The analytical yield was very satisfactory in experiments in which known amounts of cholesterol were added to untreated, as well as Millipore-filtered, samples of human bile. The analytical results of the enzymatic test agreed closely with those of a method utilizing the Liebermann-Burchard reaction. The enzymatic assay of cholesterol in bile proved to be sensitive and precise. In comparison to other methods of biliary cholesterol determination, it has the advantage of being rapid and simple.

  11. Simple Electrolyzer Model Development for High-Temperature Electrolysis System Analysis Using Solid Oxide Electrolysis Cell

    SciTech Connect

    JaeHwa Koh; DuckJoo Yoon; Chang H. Oh

    2010-07-01

    An electrolyzer model for the analysis of a hydrogen-production system using a solid oxide electrolysis cell (SOEC) has been developed, and the effects for principal parameters have been estimated by sensitivity studies based on the developed model. The main parameters considered are current density, area specific resistance, temperature, pressure, and molar fraction and flow rates in the inlet and outlet. Finally, a simple model for a high-temperature hydrogen-production system using the solid oxide electrolysis cell integrated with very high temperature reactors is estimated.

  12. Multisensory Bayesian Inference Depends on Synapse Maturation during Training: Theoretical Analysis and Neural Modeling Implementation.

    PubMed

    Ursino, Mauro; Cuppini, Cristiano; Magosso, Elisa

    2017-03-01

    Recent theoretical and experimental studies suggest that in multisensory conditions, the brain performs a near-optimal Bayesian estimate of external events, giving more weight to the more reliable stimuli. However, the neural mechanisms responsible for this behavior, and its progressive maturation in a multisensory environment, are still insufficiently understood. The aim of this letter is to analyze this problem with a neural network model of audiovisual integration, based on probabilistic population coding-the idea that a population of neurons can encode probability functions to perform Bayesian inference. The model consists of two chains of unisensory neurons (auditory and visual) topologically organized. They receive the corresponding input through a plastic receptive field and reciprocally exchange plastic cross-modal synapses, which encode the spatial co-occurrence of visual-auditory inputs. A third chain of multisensory neurons performs a simple sum of auditory and visual excitations. The work includes a theoretical part and a computer simulation study. We show how a simple rule for synapse learning (consisting of Hebbian reinforcement and a decay term) can be used during training to shrink the receptive fields and encode the unisensory likelihood functions. Hence, after training, each unisensory area realizes a maximum likelihood estimate of stimulus position (auditory or visual). In cross-modal conditions, the same learning rule can encode information on prior probability into the cross-modal synapses. Computer simulations confirm the theoretical results and show that the proposed network can realize a maximum likelihood estimate of auditory (or visual) positions in unimodal conditions and a Bayesian estimate, with moderate deviations from optimality, in cross-modal conditions. Furthermore, the model explains the ventriloquism illusion and, looking at the activity in the multimodal neurons, explains the automatic reweighting of auditory and visual inputs

  13. Theoretical analysis of BER performance of nonlinearly amplified FBMC/OQAM and OFDM signals

    NASA Astrophysics Data System (ADS)

    Bouhadda, Hanen; Shaiek, Hmaied; Roviras, Daniel; Zayani, Rafik; Medjahdi, Yahia; Bouallegue, Ridha

    2014-12-01

    In this paper, we introduce an analytical study of the impact of high-power amplifier (HPA) nonlinear distortion (NLD) on the bit error rate (BER) of multicarrier techniques. Two schemes of multicarrier modulations are considered in this work: the classical orthogonal frequency division multiplexing (OFDM) and the filter bank-based multicarrier using offset quadrature amplitude modulation (FBMC/OQAM), including different HPA models. According to Bussgang's theorem, the in-band NLD is modeled as a complex gain in addition to an independent noise term for a Gaussian input signal. The BER performance of OFDM and FBMC/OQAM modulations, transmitting over additive white Gaussian noise (AWGN) and Rayleigh fading channels, is theoretically investigated and compared to simulation results. For simple HPA models, such as the soft envelope limiter, it is easy to compute the BER theoretical expression. However, for other HPA models or for real measured HPA, BER derivation is generally intractable. In this paper, we propose a general method based on a polynomial fitting of the HPA characteristics and we give theoretical expressions for the BER for any HPA model.

  14. Engineering design and theoretical analysis of nanoporous carbon membranes for gas separation

    NASA Astrophysics Data System (ADS)

    Acharya, Madhav

    1999-11-01

    Gases are used in a direct or indirect manner in virtually every major industry, such as steel manufacturing, oil production, foodstuffs and electronics. Membranes are being investigated as an alternative to established methods of gas separation such as pressure swing adsorption and cryogenic distillation. Membranes can be used in continuous operation and work very well at ambient conditions, thus representing a tremendous energy and economic saving over the other technologies. In addition, the integration of reaction and separation into a single unit known as a membrane reactor has the potential to revolutionize the chemical industry by making selective reactions a reality. Nanoporous carbons are highly disordered materials obtained from organic polymers or natural sources. They have the ability to separate gas molecules by several different mechanisms, and hence there is a growing effort to form them into membranes. In this study, nanoporous carbon membranes were prepared on macroporous stainless steel supports of both tubular and disk geometries. The precursor used was poly(furfuryl alcohol) and different synthesis protocols were employed. A spray coating method also was developed which allowed reproducible synthesis of membranes with very few defects. High gas selectivities were obtained such as O2/N2 = 6, H2/C2H 4 = 70 and CO2/N2 = 20. Membranes also were characterized using SEM and AFM, which revealed thin layers of carbon that were quite uniform and homogeneous. The simulation of nanoporous carbon structures also was carried out using a simple algorithmic approach. 5,6 and 7-membered rings were introduced into the structure, thus resulting in considerable curvature. The density of the structures were calculated and found to compare favorably with experimental findings. Finally, a theoretical analysis of size selective transport was performed using transition state theory concepts. A definite correlation of gas permeance with molecular size was obtained after

  15. Theoretical analysis and experimental research on the finline ferrite isolator (abstract)

    NASA Astrophysics Data System (ADS)

    Zhu, Sheng-chuan; Hao, Yan-ming; Zhang, Yao-xi

    1991-04-01

    Recently, the finline ferrite devices have attracted people's attention. Beyer et al. have done theoretical and experimental researches for a finline isolator.1,2 In order to make it convenient for theoretical design and experimental adjustment of this device, we have developed a synthetical theory and have carried out the experimental research successfully.3 In this paper, we have done the further theoretical analysis and experimental researches for the finline ferrite isolator, such as the impedance matching, the effects of device structure on performances, and the transplantation of a waveguide isolator to a finline isolator problem. Good agreement between design and experiment is obtained. The performances of a X-band finline isolator are as follows A+<1.5 dB, A-≳18 dB, VSWR<1.5 in a 8% bandwidth, and the bia-field is lower (about 1000 Oe).

  16. Theoretical Noise Analysis on a Position-sensitive Metallic Magnetic Calorimeter

    NASA Technical Reports Server (NTRS)

    Smith, Stephen J.

    2007-01-01

    We report on the theoretical noise analysis for a position-sensitive Metallic Magnetic Calorimeter (MMC), consisting of MMC read-out at both ends of a large X-ray absorber. Such devices are under consideration as alternatives to other cryogenic technologies for future X-ray astronomy missions. We use a finite-element model (FEM) to numerically calculate the signal and noise response at the detector outputs and investigate the correlations between the noise measured at each MMC coupled by the absorber. We then calculate, using the optimal filter concept, the theoretical energy and position resolution across the detector and discuss the trade-offs involved in optimizing the detector design for energy resolution, position resolution and count rate. The results show, theoretically, the position-sensitive MMC concept offers impressive spectral and spatial resolving capabilities compared to pixel arrays and similar position-sensitive cryogenic technologies using Transition Edge Sensor (TES) read-out.

  17. [Theoretical analysis and experimental measurement for secondary electron yield of microchannel plate in extreme ultraviolet region].

    PubMed

    Li, Min; Ni, Qi-liang; Dong, Ning-ning; Chen, Bo

    2010-08-01

    Photon counting detectors based on microchannel plate have widespread applications in astronomy. The present paper deeply studies secondary electron of microchannel plate in extreme ultraviolet. A theoretical model describing extreme ultraviolet-excited secondary electron yield is presented, and the factor affecting on the secondary electron yields of both electrode and lead glass which consist of microchannel plate is analyzed according to theoretical formula derived from the model. The result shows that the higher secondary electron yield is obtained under appropriate condition that the thickness of material is more than 20 nm and the grazing incidence angle is larger than the critical angle. Except for several wavelengths, the secondary electron yields of both electrode and lead glass decrease along with the increase in the wavelength And also the quantum efficiency of microchannel plate is measured using quantum efficiency test set-up with laser-produced plasmas source as an extreme ultraviolet radiation source, and the result of experiment agrees with theoretical analysis.

  18. Numerical and Theoretical Analysis of Plastic Response of 5A06 Aluminum Circular Plates Subjected to Underwater Explosion Loading

    NASA Astrophysics Data System (ADS)

    Ren, Peng; Zhang, Wei

    2013-06-01

    Dynamic response analysis of structures subjected to underwater explosion loading has been always an interesting field for researchers. Understanding the deformation and failure mechanism of simple structures plays an important role in an actual project under this kind of loading. In this paper, the deformation and failure characteristics of 5A06 aluminum circular plates were investigated computationally and theoretically. The computational study was based on a Johnson-cook material parameter mode which was obtained from several previous studies provides a good description of deformation and failure of 5A06 aluminum circular plates under underwater explosion loading. The deformation history of the clamped circular plate is recorded; the maximum deflection and the thickness reduction measurements of target plates at different radii were conducted. The computational approach provided insight into the relationship between the failure mechanism and the strength of impact wave, and a computing formulae for strain field of the specimen was derived based on the same volume principle and rigid-plastic assumption. The simulation and theoretical calculation results are in good agreement with the experiments results. National Natural Science Foundation of China (NO:11272057).

  19. Exploiting green analytical procedures for acidity and iron assays employing flow analysis with simple natural reagent extracts.

    PubMed

    Grudpan, Kate; Hartwell, Supaporn Kradtap; Wongwilai, Wasin; Grudpan, Supara; Lapanantnoppakhun, Somchai

    2011-06-15

    Green analytical methods employing flow analysis with simple natural reagent extracts have been exploited. Various formats of flow based analysis systems including a single line FIA, a simple lab on chip with webcam camera detector, and a newly developed simple lab on chip system with reflective absorption detection and the simple extracts from some available local plants including butterfly pea flower, orchid flower, and beet root were investigated and shown to be useful as alternative self indicator reagents for acidity assay. Various tea drinks were explored to be used for chromogenic reagents in iron determination. The benefit of a flow based system, which allows standards and samples to go through the analysis process in exactly the same conditions, makes it possible to employ simple natural extracts with minimal or no pretreatment or purification. The combinations of non-synthetic natural reagents with minimal processed extracts and the low volume requirement flow based systems create some unique green chemical analyses.

  20. Analysis and Simple Circuit Design of Double Differential EMG Active Electrode.

    PubMed

    Guerrero, Federico Nicolás; Spinelli, Enrique Mario; Haberman, Marcelo Alejandro

    2016-06-01

    In this paper we present an analysis of the voltage amplifier needed for double differential (DD) sEMG measurements and a novel, very simple circuit for implementing DD active electrodes. The three-input amplifier that standalone DD active electrodes require is inherently different from a differential amplifier, and general knowledge about its design is scarce in the literature. First, the figures of merit of the amplifier are defined through a decomposition of its input signal into three orthogonal modes. This analysis reveals a mode containing EMG crosstalk components that the DD electrode should reject. Then, the effect of finite input impedance is analyzed. Because there are three terminals, minimum bounds for interference rejection ratios due to electrode and input impedance unbalances with two degrees of freedom are obtained. Finally, a novel circuit design is presented, including only a quadruple operational amplifier and a few passive components. This design is nearly as simple as the branched electrode and much simpler than the three instrumentation amplifier design, while providing robust EMG crosstalk rejection and better input impedance using unity gain buffers for each electrode input. The interference rejection limits of this input stage are analyzed. An easily replicable implementation of the proposed circuit is described, together with a parameter design guideline to adjust it to specific needs. The electrode is compared with the established alternatives, and sample sEMG signals are obtained, acquired on different body locations with dry contacts, successfully rejecting interference sources.

  1. Analysis and Simple Circuit Design of Double Differential EMG Active Electrode.

    PubMed

    Guerrero, Federico Nicolas; Spinelli, Enrique Mario; Haberman, Marcelo Alejandro

    2015-12-22

    In this paper we present an analysis of the voltage amplifier needed for double differential (DD) sEMG measurements and a novel, very simple circuit for implementing DD active electrodes. The three-input amplifier that standalone DD active electrodes require is inherently different from a differential amplifier, and general knowledge about its design is scarce in the literature. First, the figures of merit of the amplifier are defined through a decomposition of its input signal into three orthogonal modes. This analysis reveals a mode containing EMG crosstalk components that the DD electrode should reject. Then, the effect of finite input impedance is analyzed. Because there are three terminals, minimum bounds for interference rejection ratios due to electrode and input impedance unbalances with two degrees of freedom are obtained. Finally, a novel circuit design is presented, including only a quadruple operational amplifier and a few passive components. This design is nearly as simple as the branched electrode and much simpler than the three instrumentation amplifier design, while providing robust EMG crosstalk rejection and better input impedance using unity gain buffers for each electrode input. The interference rejection limits of this input stage are analyzed. An easily replicable implementation of the proposed circuit is described, together with a parameter design guideline to adjust it to specific needs. The electrode is compared with the established alternatives, and sample sEMG signals are obtained, acquired on different body locations with dry contacts, successfully rejecting interference sources.

  2. Simple spot method of image analysis for evaluation of highly marbled beef.

    PubMed

    Irie, M; Kohira, K

    2012-04-01

    The simple method of evaluating highly marbled beef was examined by image analysis. The images of the cross section at the 6 to 7th rib were obtained from 82 carcasses of Wagyu cattle. By using an overall trace method, the surrounding edges of the longissimus thoracis and three muscles were traced automatically and manually with image analysis. In a spot method, 3 to 5 locations (2.5 or 3.0 cm in diameter) for each muscle were rapidly selected with no manual trace. The images were flattened, binarized, and the ratio of fat area to muscle area was determined. The correlation coefficients for marbling between different muscles, and between the overall trace and the spot methods were 0.55 to 0.81 between different muscles and 0.89 to 0.97, respectively. These results suggested that the simple spot method is speedy and almost as useful as the overall trace method as a measuring technique for beef marbling in loin muscles, especially for highly marbled beef.

  3. A simple element for multilayer beams in NASTRAN thermal stress analysis

    NASA Technical Reports Server (NTRS)

    Chen, W. T.; Wadhwa, S. K.

    1978-01-01

    In the application of NASTRAN, structural members are usually represented by bar elements with multipoint constraint cards to enforce the interface conditions. While this is a very powerful method in principle, it was found that in practice the process for specification of constraints became tedious and error prone, unless the geometry was simple and the number of grid points low. An alternative approach was found within the framework of the NASTRAN program. This approach made use of the idea that a thermal distortion in a multilayer beam may be similar to a homogeneous beam with a thermal gradient across the cross section. The exact mathematical derivation for the equivalent beam, and all the necessary formulae for the equivalent parameters in NASTRAN analysis are presented. Some numerical examples illustrate the simplicity and ease of this approach for finite element analysis.

  4. Post-buckling and Large Amplitude Free Vibration Analysis of Composite Beams: Simple Intuitive Formulation

    NASA Astrophysics Data System (ADS)

    Gunda, Jagadish Babu; Venkateswara Rao, Gundabathula

    2016-04-01

    Post-buckling and large amplitude free vibration analysis of composite beams with axially immovable ends is investigated in the present study using a simple intuitive formulation. Geometric nonlinearity of Von-Karman type is considered in the analysis which accounts for mid-plane stretching action of the beam. Intuitive formulation uses only two parameters: the critical bifurcation point and the axial stretching force developed due to membrane stretching action of the beam. Hinged-hinged, clamped-clamped and clamped-hinged boundary conditions are considered. Numerical accuracy of the proposed analytical closed-form solutions obtained from the intuitive formulation are compared to available finite element solutions for symmetric and asymmetric layup schemes of laminated composite beam which indicates the confidence gained on the present formulation.

  5. A simple apparatus for quick qualitative analysis of CR39 nuclear track detectors

    SciTech Connect

    Gautier, D. C.; Kline, J. L.; Flippo, K. A.; Gaillard, S. A.; Letzring, S. A.; Hegelich, B. M.

    2008-10-15

    Quantifying the ion pits in Columbia Resin 39 (CR39) nuclear track detector from Thomson parabolas is a time consuming and tedious process using conventional microscope based techniques. A simple inventive apparatus for fast screening and qualitative analysis of CR39 detectors has been developed, enabling efficient selection of data for a more detailed analysis. The system consists simply of a green He-Ne laser and a high-resolution digital single-lens reflex camera. The laser illuminates the edge of the CR39 at grazing incidence and couples into the plastic, acting as a light pipe. Subsequently, the laser illuminates all ion tracks on the surface. A high-resolution digital camera is used to photograph the scattered light from the ion tracks, enabling one to quickly determine charge states and energies measured by the Thomson parabola.

  6. Direct power comparisons between simple LOD scores and NPL scores for linkage analysis in complex diseases.

    PubMed

    Abreu, P C; Greenberg, D A; Hodge, S E

    1999-09-01

    Several methods have been proposed for linkage analysis of complex traits with unknown mode of inheritance. These methods include the LOD score maximized over disease models (MMLS) and the "nonparametric" linkage (NPL) statistic. In previous work, we evaluated the increase of type I error when maximizing over two or more genetic models, and we compared the power of MMLS to detect linkage, in a number of complex modes of inheritance, with analysis assuming the true model. In the present study, we compare MMLS and NPL directly. We simulated 100 data sets with 20 families each, using 26 generating models: (1) 4 intermediate models (penetrance of heterozygote between that of the two homozygotes); (2) 6 two-locus additive models; and (3) 16 two-locus heterogeneity models (admixture alpha = 1.0,.7,.5, and.3; alpha = 1.0 replicates simple Mendelian models). For LOD scores, we assumed dominant and recessive inheritance with 50% penetrance. We took the higher of the two maximum LOD scores and subtracted 0.3 to correct for multiple tests (MMLS-C). We compared expected maximum LOD scores and power, using MMLS-C and NPL as well as the true model. Since NPL uses only the affected family members, we also performed an affecteds-only analysis using MMLS-C. The MMLS-C was both uniformly more powerful than NPL for most cases we examined, except when linkage information was low, and close to the results for the true model under locus heterogeneity. We still found better power for the MMLS-C compared with NPL in affecteds-only analysis. The results show that use of two simple modes of inheritance at a fixed penetrance can have more power than NPL when the trait mode of inheritance is complex and when there is heterogeneity in the data set.

  7. Bias in meta-analysis detected by a simple, graphical test.

    PubMed Central

    Egger, M.; Davey Smith, G.; Schneider, M.; Minder, C.

    1997-01-01

    OBJECTIVE: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. DESIGN: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews. MAIN OUTCOME MEASURE: Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. RESULTS: In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. CONCLUSIONS: A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution. PMID:9310563

  8. Experimental and theoretical analysis of a hybrid solar thermoelectric generator with forced convection cooling

    NASA Astrophysics Data System (ADS)

    Sundarraj, Pradeepkumar; Taylor, Robert A.; Banerjee, Debosmita; Maity, Dipak; Sinha Roy, Susanta

    2017-01-01

    Hybrid solar thermoelectric generators (HSTEGs) have garnered significant research attention recently due to their potential ability to cogenerate heat and electricity. In this paper, theoretical and experimental investigations of the electrical and thermal performance of a HSTEG system are reported. In order to validate the theoretical model, a laboratory scale HSTEG system (based on forced convection cooling) is developed. The HSTEG consists of six thermoelectric generator modules, an electrical heater, and a stainless steel cooling block. Our experimental analysis shows that the HSTEG is capable of producing a maximum electrical power output of 4.7 W, an electrical efficiency of 1.2% and thermal efficiency of 61% for an average temperature difference of 92 °C across the TEG modules with a heater power input of 382 W. These experimental results of the HSTEG system are found to be in good agreement with the theoretical prediction. This experimental/theoretical analysis can also serve as a guide for evaluating the performance of the HSTEG system with forced convection cooling.

  9. Local structure of Se in cancrinite: X-ray absorption fine structure theoretical analysis

    NASA Astrophysics Data System (ADS)

    Soldatov, A. V.; Yalovega, G. E.

    2000-04-01

    A theoretical "ab initio" analysis of the polarized X-ray absorption spectrum of selenium in a cancrinite matrix based on a full multiple-scattering theory has been performed. Comparison of the theoretical spectra with the experimental results shows that Se atoms form dimerized chains in the channels of the cancrinite matrix with an interchain distance of about 4.8 Å. In addition the distribution of unoccupied partial s-, p- and d- electronic states of Se has been obtained. Density of states analysis provides some insight into the chemical bonding of Se in cancrinite. The results suggest that the interaction of Se atoms with the matrix is the cause of the unusually large Se-Se distance in dimers.

  10. Economic Analysis in the Pacific Northwest Land Resources Project: Theoretical Considerations and Preliminary Results

    NASA Technical Reports Server (NTRS)

    Morse, D. R. A.; Sahlberg, J. T.

    1977-01-01

    The Pacific Northwest Land Resources Inventory Demonstration Project i s an a ttempt to combine a whole spectrum of heterogeneous geographic, institutional and applications elements in a synergistic approach to the evaluation of remote sensing techniques. This diversity is the prime motivating factor behind a theoretical investigation of alternative economic analysis procedures. For a multitude of reasons--simplicity, ease of understanding, financial constraints and credibility, among others--cost-effectiveness emerges as the most practical tool for conducting such evaluation determinatIons in the Pacific Northwest. Preliminary findings in two water resource application areas suggest, in conformity with most published studies, that Lands at-aided data collection methods enjoy substantial cost advantages over alternative techniques. The pntential for sensitivity analysis based on cost/accuracy tradeoffs is considered on a theoretical plane in the absence of current accuracy figures concerning the Landsat-aided approach.

  11. Theoretical analysis of mode instability in high-power fiber amplifiers.

    PubMed

    Hansen, Kristian Rymann; Alkeskjold, Thomas Tanggaard; Broeng, Jes; Lægsgaard, Jesper

    2013-01-28

    We present a simple theoretical model of transverse mode instability in high-power rare-earth doped fiber amplifiers. The model shows that efficient power transfer between the fundamental and higher-order modes of the fiber can be induced by a nonlinear interaction mediated through the thermo-optic effect, leading to transverse mode instability. The temporal and spectral characteristics of the instability dynamics are investigated, and it is shown that the instability can be seeded by both quantum noise and signal intensity noise, while pure phase noise of the signal does not induce instability. It is also shown that the presence of a small harmonic amplitude modulation of the signal can lead to generation of higher harmonics in the output intensity when operating near the instability threshold.

  12. Nanoscale deflection detection of a cantilever-based biosensor using MOSFET structure: A theoretical analysis

    NASA Astrophysics Data System (ADS)

    Paryavi, Mohsen; Montazeri, Abbas; Tekieh, Tahereh; Sasanpour, Pezhman

    2016-10-01

    A novel method for detection of biological species based on measurement of cantilever deflection has been proposed and numerically evaluated. Employing the cantilever as a moving gate of a MOSFET structure, its deflection can be analyzed via current characterization of the MOSFET consequently. Locating the cantilever as a suspended gate of a MOSFET on a substrate, the distance between cantilever and oxide layer will change the carrier concentration. Accordingly, it will be resulted in different current voltage characteristics of the device which can be easily measured using simple apparatuses. In order to verify the proposed method, the performance of system has been theoretically analyzed using COMSOL platform. The simulation results have confirmed the performance and sensitivity of the proposed method.

  13. Aerodynamic design and analysis system for supersonic aircraft. Part 1: General description and theoretical development

    NASA Technical Reports Server (NTRS)

    Middleton, W. D.; Lundry, J. L.

    1975-01-01

    An integrated system of computer programs has been developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. This part presents a general description of the system and describes the theoretical methods used.

  14. Can Computer-Mediated Interventions Change Theoretical Mediators of Safer Sex? A Meta-Analysis

    ERIC Educational Resources Information Center

    Noar, Seth M.; Pierce, Larson B.; Black, Hulda G.

    2010-01-01

    The purpose of this study was to conduct a meta-analysis of computer-mediated interventions (CMIs) aimed at changing theoretical mediators of safer sex. Meta-analytic aggregation of effect sizes from k = 20 studies indicated that CMIs significantly improved HIV/AIDS knowledge, d = 0.276, p less than 0.001, k = 15, N = 6,625; sexual/condom…

  15. Theoretical Analysis of the Longitudinal Behavior of an Automatically Controlled Supersonic Interceptor During the Attack Phase

    NASA Technical Reports Server (NTRS)

    Gates, Ordway B., Jr.; Woodling, C. H.

    1959-01-01

    Theoretical analysis of the longitudinal behavior of an automatically controlled supersonic interceptor during the attack phase against a nonmaneuvering target is presented. Control of the interceptor's flight path is obtained by use of a pitch rate command system. Topics lift, and pitching moment, effects of initial tracking errors, discussion of normal acceleration limited, limitations of control surface rate and deflection, and effects of neglecting forward velocity changes of interceptor during attack phase.

  16. Moving Target Detection with Along-Track SAR Interferometry. A Theoretical Analysis

    DTIC Science & Technology

    2002-08-01

    1994). Intensity and Phase Statistics of Multilook Polarimetric and Interfer- ometric SAR Imagery. IEEE Trans. Geoscience and Remote Sensing, GRS-32(5... Multilook Polarimetric Signatures. IEEE Trans. Geoscience and Remote Sensing, GRS-32(3), 562-574. 4. Gierull, C.H. (July 2001). Statistics of SAR ...Along-Track SAR Interferometry A Theoretical Analysis Christoph H. Gierull DISTRIBUTION STATEMENTA Approved for Public Release Distribution Unlimited

  17. A simple method for the analysis of neutron resonance capture spectra

    SciTech Connect

    Clarijs, Martijn C.; Bom, Victor R.; Eijk, Carel W. E. van

    2009-03-15

    Neutron resonance capture analysis (NRCA) is a method used to determine the bulk composition of various kinds of objects and materials. It is based on analyzing direct capture resonance peaks. However, the analysis is complicated by scattering followed by capture effects in the object itself. These effects depend on the object's shape and size. In this paper the new Delft elemental analysis program (DEAP) is presented which can automatically and quickly analyze multiple NRCA spectra in a practical and simple way, yielding the elemental bulk composition of an object, largely independent of its shape and size. The DEAP method is demonstrated with data obtained with a Roman bronze water tap excavated in Nijmegen (The Netherlands). DEAP will also be used in the framework of the Ancient Charm project as data analysis program for neutron resonance capture imaging (NRCI) experiments. NRCI provides three-dimensional visualization and quantification of the internal structure of archaeological objects by performing scanning measurements with narrowly collimated neutron beams on archaeological objects in computed tomography based experimental setups. The large amounts (hundreds to thousands) of spectra produced during a NRCI experiment can automatically and quickly be analyzed by DEAP.

  18. A Simple, Approximate Method for Analysis of Kerr-Newman Black Hole Dynamics and Thermodynamics

    NASA Astrophysics Data System (ADS)

    Pankovic, V.; Ciganovic, S.; Glavatovic, R.

    2009-06-01

    In this work we present a simple approximate method for analysis of the basic dynamical and thermodynamical characteristics of Kerr-Newman black hole. Instead of the complete dynamics of the black hole self-interaction, we consider only the stable (stationary) dynamical situations determined by condition that the black hole (outer) horizon "circumference" holds the integer number of the reduced Compton wave lengths corresponding to mass spectrum of a small quantum system (representing the quantum of the black hole self-interaction). Then, we show that Kerr-Newman black hole entropy represents simply the ratio of the sum of static part and rotation part of the mass of black hole on one hand, and the ground mass of small quantum system on the other hand. Also we show that Kerr-Newman black hole temperature represents the negative value of the classical potential energy of gravitational interaction between a part of black hole with reduced mass and a small quantum system in the ground mass quantum state. Finally, we suggest a bosonic great canonical distribution of the statistical ensemble of given small quantum systems in the thermodynamical equilibrium with (macroscopic) black hole as thermal reservoir. We suggest that, practically, only the ground mass quantum state is significantly degenerate while all the other, excited mass quantum states, are non-degenerate. Kerr-Newman black hole entropy is practically equivalent to the ground mass quantum state degeneration. Given statistical distribution admits a rough (qualitative) but simple modeling of Hawking radiation of the black hole too.

  19. A Theoretical Analysis of the Influence of Electroosmosis on the Effective Ionic Mobility in Capillary Zone Electrophoresis

    ERIC Educational Resources Information Center

    Hijnen, Hens

    2009-01-01

    A theoretical description of the influence of electroosmosis on the effective mobility of simple ions in capillary zone electrophoresis is presented. The mathematical equations derived from the space-charge model contain the pK[subscript a] value and the density of the weak acid surface groups as parameters characterizing the capillary. It is…

  20. PyKE: Reduction and analysis of Kepler Simple Aperture Photometry data

    NASA Astrophysics Data System (ADS)

    Still, Martin; Barclay, Tom

    2012-08-01

    PyKE is a python-based PyRAF package that can also be run as a stand-alone program within a unix-based shell without compiling against PyRAF. It is a group of tasks developed for the reduction and analysis of Kepler Simple Aperture Photometry (SAP) data of individual targets with individual characteristics. The main purposes of these tasks are to i) re-extract light curves from manually-chosen pixel apertures and ii) cotrend and/or detrend the data in order to reduce or remove systematic noise structure using methods tunable to user and target-specific requirements. PyKE is an open source project and contributions of new tasks or enhanced functionality of existing tasks by the community are welcome.

  1. In-silico analysis of simple and imperfect microsatellites in diverse tobamovirus genomes.

    PubMed

    Alam, Chaudhary Mashhood; Singh, Avadhesh Kumar; Sharfuddin, Choudhary; Ali, Safdar

    2013-11-10

    An in-silico analysis of simple sequence repeats (SSRs) in 30 species of tobamoviruses was done. SSRs (mono to hexa) were present with variant frequency across species. Compound microsatellites, primarily of variant motifs accounted for up to 11.43% of the SSRs. Motif duplications were observed for A, T, AT, and ACA repeats. (AG)-(TC) was the most prevalent SSR-couple. SSRs were differentially localized in the coding region with ~54% on the 128 kDa protein while 20.37% was exclusive to 186 kDa protein. Characterization of such variations is important for elucidating the origin, sequence variations, and structure of these widely used, but incompletely understood sequences.

  2. Entropy analysis reveals a simple linear relation between laser speckle and blood flow.

    PubMed

    Miao, Peng; Chao, Zhen; Zhang, Yiguang; Li, Nan; Thakor, Nitish V

    2014-07-01

    Dynamic laser speckles contain motion information of scattering particles which can be estimated by laser speckle contrast analysis (LASCA). In this work, an entropy-based method was proposed to provide a more robust estimation of motion speed. An in vitro flow simulation experiment confirmed a simple linear relation between entropy, exposure time, and speed. A multimodality optical imaging setup is developed to validate the advantages of the entropy method based on laser speckle imaging, green light imaging, and fluorescence imaging. The entropy method overcomes traditional LASCA with less noisy interference, and extracts more visible and detailed vasculatures in vivo. Furthermore, the entropy method provides a more accurate estimation and a stable pattern of blood flow activations in the rat's somatosensory area under multitrial hand paw stimulations.

  3. Poly: a quantitative analysis tool for simple sequence repeat (SSR) tracts in DNA

    PubMed Central

    Bizzaro, Jeff W; Marx, Kenneth A

    2003-01-01

    Background Simple sequence repeats (SSRs), microsatellites or polymeric sequences are common in DNA and are important biologically. From mononucleotide to trinucleotide repeats and beyond, they can be found in long (> 6 repeating units) tracts and may be characterized by quantifying the frequencies in which they are found and their tract lengths. However, most of the existing computer programs that find SSR tracts do not include these methods. Results A computer program named Poly has been written not only to find SSR tracts but to analyze the results quantitatively. Conclusions Poly is significant in its use of non-standard, quantitative methods of analysis. And, with its flexible object model and data structure, Poly and its generated data can be used for even more sophisticated analyses. PMID:12791171

  4. Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity.

    PubMed

    Li, Harbin; McNulty, Steven G

    2007-10-01

    Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL estimates to the national scale could be developed. Specifically, we wanted to quantify CAL uncertainty under natural variability in 17 model parameters, and determine their relative contributions in predicting CAL. Results indicated that uncertainty in CAL came primarily from components of base cation weathering (BC(w); 49%) and acid neutralizing capacity (46%), whereas the most critical parameters were BC(w) base rate (62%), soil depth (20%), and soil temperature (11%). Thus, improvements in estimates of these factors are crucial to reducing uncertainty and successfully scaling up SMBE for national assessments of CAL.

  5. Experimental and theoretical analysis of the performance of Stirling engine with pendulum type displacer

    SciTech Connect

    Isshiki, Seita; Isshiki, Naotsugu; Takanose, Eiichiro; Igawa, Yoshiharu

    1995-12-31

    This paper describes the detailed experimental and theoretical performance of new type Stirling engine with pendulum type displacer (PDSE) which was proposed last year. This kind of engine has a pendulum type displacer suspended by the hinge shaft, and swings right and left in displacer space. The present paper mainly discusses the PDSE-3B which is an atmospheric 30[W] engine heated by fuel and cooled by water. It is clear that power required to provide a pendulum type displacer motion is expressed as a simple equation consisting of viscous flow loss term proportional to the square of rotational speed and dynamic pressure loss term proportional to the cube of rotational speed. It is also clear that theoretical engine power defined as the difference between experimental indicated power and power required to provide pendulum type displacer motion agrees well with the experimental engine power. It is also clear that measured Nusselt number of regenerator`s wire meshes agreed with the equation of previous study. In conclusion, PDSE is considered effective for measuring many aspects of performance of the Stirling engine.

  6. Analysis and Modeling of the Arctic Oscillation Using a Simple Barotropic Model with Baroclinic Eddy Forcing.

    NASA Astrophysics Data System (ADS)

    Tanaka, H. L.

    2003-06-01

    In this study, a numerical simulation of the Arctic Oscillation (AO) is conducted using a simple barotropic model that considers the barotropic-baroclinic interactions as the external forcing. The model is referred to as a barotropic S model since the external forcing is obtained statistically from the long-term historical data, solving an inverse problem. The barotropic S model has been integrated for 51 years under a perpetual January condition and the dominant empirical orthogonal function (EOF) modes in the model have been analyzed. The results are compared with the EOF analysis of the barotropic component of the real atmosphere based on the daily NCEP-NCAR reanalysis for 50 yr from 1950 to 1999.According to the result, the first EOF of the model atmosphere appears to be the AO similar to the observation. The annular structure of the AO and the two centers of action at Pacific and Atlantic are simulated nicely by the barotropic S model. Therefore, the atmospheric low-frequency variabilities have been captured satisfactorily even by the simple barotropic model.The EOF analysis is further conducted to the external forcing of the barotropic S model. The structure of the dominant forcing shows the characteristics of synoptic-scale disturbances of zonal wavenumber 6 along the Pacific storm track. The forcing is induced by the barotropic-baroclinic interactions associated with baroclinic instability.The result suggests that the AO can be understood as the natural variability of the barotropic component of the atmosphere induced by the inherent barotropic dynamics, which is forced by the barotropic-baroclinic interactions. The fluctuating upscale energy cascade from planetary waves and synoptic disturbances to the zonal motion plays the key role for the excitation of the AO.

  7. Analysis of simple 2-D and 3-D metal structures subjected to fragment impact

    NASA Technical Reports Server (NTRS)

    Witmer, E. A.; Stagliano, T. R.; Spilker, R. L.; Rodal, J. J. A.

    1977-01-01

    Theoretical methods were developed for predicting the large-deflection elastic-plastic transient structural responses of metal containment or deflector (C/D) structures to cope with rotor burst fragment impact attack. For two-dimensional C/D structures both, finite element and finite difference analysis methods were employed to analyze structural response produced by either prescribed transient loads or fragment impact. For the latter category, two time-wise step-by-step analysis procedures were devised to predict the structural responses resulting from a succession of fragment impacts: the collision force method (CFM) which utilizes an approximate prediction of the force applied to the attacked structure during fragment impact, and the collision imparted velocity method (CIVM) in which the impact-induced velocity increment acquired by a region of the impacted structure near the impact point is computed. The merits and limitations of these approaches are discussed. For the analysis of 3-d responses of C/D structures, only the CIVM approach was investigated.

  8. Blade loss transient dynamics analysis, volume 1. Task 2: TETRA 2 theoretical development

    NASA Technical Reports Server (NTRS)

    Gallardo, Vincente C.; Black, Gerald

    1986-01-01

    The theoretical development of the forced steady state analysis of the structural dynamic response of a turbine engine having nonlinear connecting elements is discussed. Based on modal synthesis, and the principle of harmonic balance, the governing relations are the compatibility of displacements at the nonlinear connecting elements. There are four displacement compatibility equations at each nonlinear connection, which are solved by iteration for the principle harmonic of the excitation frequency. The resulting computer program, TETRA 2, combines the original TETRA transient analysis (with flexible bladed disk) with the steady state capability. A more versatile nonlinear rub or bearing element which contains a hardening (or softening) spring, with or without deadband, is also incorporated.

  9. Simple sequence repeat analysis of genetic diversity in primary core collection of peach (Prunus persica).

    PubMed

    Li, Tian-Hong; Li, Yin-Xia; Li, Zi-Chao; Zhang, Hong-Liang; Qi, Yong-Wen; Wang, Tao

    2008-01-01

    In this study, the genetic diversity of 51 cultivars in the primary core collection of peach (Prunus persica (L.) Batsch) was evaluated by using simple sequence repeats (SSRs). The phylogenetic relationships and the evolutionary history among different cultivars were determined on the basis of SSR data. Twenty-two polymorphic SSR primer pairs were selected, and a total of 111 alleles were identified in the 51 cultivars, with an average of 5 alleles per locus. According to traditional Chinese classification of peach cultivars, the 51 cultivars in the peach primary core collection belong to six variety groups. The SSR analysis revealed that the levels of the genetic diversity within each variety group were ranked as Sweet peach > Crisp peach > Flat peach > Nectarine > Honey Peach > Yellow fleshed peach. The genetic diversity among the Chinese cultivars was higher than that among the introduced cultivars. Cluster analysis by the unweighted pair group method with arithmetic averaging (UPGMA) placed the 51 cultivars into five linkage clusters. Cultivar members from the same variety group were distributed in different UPGMA clusters and some members from different variety groups were placed under the same cluster. Different variety groups could not be differentiated in accordance with SSR markers. The SSR analysis revealed rich genetic diversity in the peach primary core collection, representative of genetic resources of peach.

  10. AppEEARS: Simple and Intuitive Access to Analysis Ready Data

    NASA Astrophysics Data System (ADS)

    Quenzer, R.; Friesz, A. M.

    2015-12-01

    Many search and discovery tools for satellite land remote sensing data archives are often catalog-based and can only be queried at a granule level requiring remote sensing data users to download and process entire data files before science questions can be addressed. Methods for accessing remote sensing data archives must become more precise in order to allow users to concisely extract study relevant information from rapidly expanding archives. To address the need, NASA's Land Processes Distributed Active Archive Center (LP DAAC) is developing AppEEARS (Application for Extracting and Exploring Analysis Ready Samples). Built on top of middleware services, the AppEEARS user interface facilitates input of precise sample locations, such as field study sites or flux towers, to extract analysis-ready data from land MODIS products held by NASA's LP DAAC. AppEEARS provides simple and intuitive access to LP DAAC's land MODIS products. For a given set of sample locations, AppEEARS returns pixel values that intersect with the provided locations through the requested date range. Additionally, the AppEEARS user interface provides exploratory data analysis services (e.g. time series and scatter plots) allowing users to interact and explore the requested data and its associated quality information before downloading. AppEEARS delivers study relevant data sets requiring little more processing allowing users to spend less time performing data preparation routines and more time answer questions.

  11. Activation of attention networks using frequency analysis of a simple auditory-motor paradigm.

    PubMed

    Astrakas, Loukas G; Teicher, Martin; Tzika, A Aria

    2002-04-01

    The purpose of this study was to devise a paradigm that stimulates attention using a frequency-based analysis of the data acquired during a motor task. Six adults (30-40 years of age) and one child (10 years) were studied. Each subject was requested to attend to "start" and "stop" commands every 20 s alternatively and had to respond with the motor task every second time. Attention was stimulated during a block-designed, motor paradigm in which a start-stop commands cycle produced activation at the fourth harmonic of the motor frequency. We disentangled the motor and attention functions using statistical analysis with subspaces spanned by vectors generated by a truncated trigonometric series of motor and attention frequency. During our auditory-motor paradigm, all subjects showed activation in areas that belong to an extensive attention network. Attention and motor functions were coactivated but with different frequencies. While the motor-task-related areas were activated with slower frequency than attention, the activation in the attention-related areas was enhanced every time the subject had to start or end the motor task. We suggest that although a simple block-designed, auditory-motor paradigm stimulates the attention network, motor preparation, and motor inhibition concurrently, a frequency-based analysis can distinguish attention from motor functions. Due to its simplicity the paradigm can be valuable in studying children with attention deficit disorders.

  12. The Probabilistic Analysis of Language Acquisition: Theoretical, Computational, and Experimental Analysis

    ERIC Educational Resources Information Center

    Hsu, Anne S.; Chater, Nick; Vitanyi, Paul M. B.

    2011-01-01

    There is much debate over the degree to which language learning is governed by innate language-specific biases, or acquired through cognition-general principles. Here we examine the probabilistic language acquisition hypothesis on three levels: We outline a novel theoretical result showing that it is possible to learn the exact "generative model"…

  13. Security Analysis of Smart Grid Cyber Physical Infrastructures Using Modeling and Game Theoretic Simulation

    SciTech Connect

    Abercrombie, Robert K; Sheldon, Frederick T.

    2015-01-01

    Cyber physical computing infrastructures typically consist of a number of sites are interconnected. Its operation critically depends both on cyber components and physical components. Both types of components are subject to attacks of different kinds and frequencies, which must be accounted for the initial provisioning and subsequent operation of the infrastructure via information security analysis. Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. We concentrated our analysis on the electric sector failure scenarios and impact analyses by the NESCOR Working Group Study, From the Section 5 electric sector representative failure scenarios; we extracted the four generic failure scenarios and grouped them into three specific threat categories (confidentiality, integrity, and availability) to the system. These specific failure scenarios serve as a demonstration of our simulation. The analysis using our ABGT simulation demonstrates how to model the electric sector functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the cyber physical infrastructure network with respect to CIA.

  14. Creativity in theoretical physics: A situational analysis of the fifth Solvay Council on Physics, 1927

    NASA Astrophysics Data System (ADS)

    First, Leili K.

    This dissertation investigates the intersections and interactions of factors which enhance and inhibit creativity in theoretical physics research, using a situational analysis of the fifth Solvay Council on Physics of 1927 (Solvay 1927), a pivotal point in the history of quantum physics. Situational analysis is a postmodern variant of the grounded theory method which views a situation as the unit of analysis and adds situational mapping as an analytic tool. This method specifically works against normalizing or simplifying the points of view, instead drawing out diversity, complexity, and contradiction. It results in "theorizing" rather than theory. This research differs from other analyses of the development of quantum mechanics in looking at technical issues as well as individual, collective, and societal factors. Data examined in this historical analysis includes theoretical papers, conference proceedings, personal letters, and commentary and analysis, both contemporaneous and modern. Literature related to scientific creativity was also consulted. Mapping the situation as a master discourse of Niels Bohr overlapping and interacting with co-existent major discourses on matrix mechanics/Copenhagen interpretation, wave mechanics, and the pilot-wave theory resulted in the most descriptive illustration of the factors influencing scientific creativity before and after Solvay 1927. The master discourse strongly influenced the major discourses and generated the "Copenhagen spirit" which effectively marginalized discourses other than matrix mechanics/Copenhagen interpretation after Solvay 1927.

  15. An Experimental-Theoretical Analysis of Protein Adsorption on Peptidomimetic Polymer Brushes

    PubMed Central

    Lau, K.H. Aaron; Ren, Chunlai; Park, Sung Hyun; Szleifer, Igal; Messersmith, Phillip B.

    2012-01-01

    Surface-grafted water soluble polymer brushes are being intensely investigated for preventing protein adsorption to improve biomedical device function, prevent marine fouling, and enable applications in biosensing and tissue engineering. In this contribution, we present an experimental-theoretical analysis of a peptidomimetic polymer brush system with regard to the critical brush density required for preventing protein adsorption at varying chain lengths. A mussel adhesive-inspired DOPA-Lys pentapeptide surface grafting motif enabled aqueous deposition of our peptidomimetic polypeptoid brushes over a wide range of chain densities. Critical densities of 0.88 nm−2 for a relatively short polypeptoid 10-mer to 0.42 nm−2 for a 50-mer were identified from measurements of protein adsorption. The experiments were also compared with the protein adsorption isotherms predicted by a molecular theory. Excellent agreements in terms of both the polymer brush structure and the critical chain density were obtained. Furthermore, atomic force microscopy (AFM) imaging is shown to be useful in verifying the critical brush density for preventing protein adsorption. The present co-analysis of experimental and theoretical results demonstrates the significance of characterizing the critical brush density in evaluating the performance of an anti-fouling polymer brush system. The high fidelity of the agreement between the experiments and molecular theory also indicate that the theoretical approach presented can aid in the practical design of antifouling polymer brush systems. PMID:22107438

  16. Elastic Cherenkov effects in transversely isotropic soft materials-I: Theoretical analysis, simulations and inverse method

    NASA Astrophysics Data System (ADS)

    Li, Guo-Yang; Zheng, Yang; Liu, Yanlin; Destrade, Michel; Cao, Yanping

    2016-11-01

    A body force concentrated at a point and moving at a high speed can induce shear-wave Mach cones in dusty-plasma crystals or soft materials, as observed experimentally and named the elastic Cherenkov effect (ECE). The ECE in soft materials forms the basis of the supersonic shear imaging (SSI) technique, an ultrasound-based dynamic elastography method applied in clinics in recent years. Previous studies on the ECE in soft materials have focused on isotropic material models. In this paper, we investigate the existence and key features of the ECE in anisotropic soft media, by using both theoretical analysis and finite element (FE) simulations, and we apply the results to the non-invasive and non-destructive characterization of biological soft tissues. We also theoretically study the characteristics of the shear waves induced in a deformed hyperelastic anisotropic soft material by a source moving with high speed, considering that contact between the ultrasound probe and the soft tissue may lead to finite deformation. On the basis of our theoretical analysis and numerical simulations, we propose an inverse approach to infer both the anisotropic and hyperelastic parameters of incompressible transversely isotropic (TI) soft materials. Finally, we investigate the properties of the solutions to the inverse problem by deriving the condition numbers in analytical form and performing numerical experiments. In Part II of the paper, both ex vivo and in vivo experiments are conducted to demonstrate the applicability of the inverse method in practical use.

  17. Asynchronous cellular automaton-based neuron: theoretical analysis and on-FPGA learning.

    PubMed

    Matsubara, Takashi; Torikai, Hiroyuki

    2013-05-01

    A generalized asynchronous cellular automaton-based neuron model is a special kind of cellular automaton that is designed to mimic the nonlinear dynamics of neurons. The model can be implemented as an asynchronous sequential logic circuit and its control parameter is the pattern of wires among the circuit elements that is adjustable after implementation in a field-programmable gate array (FPGA) device. In this paper, a novel theoretical analysis method for the model is presented. Using this method, stabilities of neuron-like orbits and occurrence mechanisms of neuron-like bifurcations of the model are clarified theoretically. Also, a novel learning algorithm for the model is presented. An equivalent experiment shows that an FPGA-implemented learning algorithm enables an FPGA-implemented model to automatically reproduce typical nonlinear responses and occurrence mechanisms observed in biological and model neurons.

  18. Theoretical and experimental analysis of the lubricating system of a high speed multiplier

    NASA Astrophysics Data System (ADS)

    Marian, V. G.; Mirică, R. F.; Prisecaru, T.

    2017-02-01

    Flywheel-based energy storage systems are used for energy storage in form of kinetic energy using a flywheel rotating at high speed. In order to achieve this high rotating speed a high speed multiplier could be used in order to increase the rotation speed of a conventional motor. This article presents a theoretical and experimental analysis of the lubricating system of a high speed multiplier used in a flywheel-based energy storage system. The necessary oil flow is theoretically computed using analytical formulas. The oil is used for lubricating the gears, the roller bearings and the sliding bearings. An experimental test rig is used to measure the oil flow. Finally the two results are compared.

  19. Experimental and theoretical oscillator strengths of Mg i for accurate abundance analysis

    NASA Astrophysics Data System (ADS)

    Pehlivan Rhodin, A.; Hartman, H.; Nilsson, H.; Jönsson, P.

    2017-02-01

    Context. With the aid of stellar abundance analysis, it is possible to study the galactic formation and evolution. Magnesium is an important element to trace the α-element evolution in our Galaxy. For chemical abundance analysis, such as magnesium abundance, accurate and complete atomic data are essential. Inaccurate atomic data lead to uncertain abundances and prevent discrimination between different evolution models. Aims: We study the spectrum of neutral magnesium from laboratory measurements and theoretical calculations. Our aim is to improve the oscillator strengths (f-values) of Mg i lines and to create a complete set of accurate atomic data, particularly for the near-IR region. Methods: We derived oscillator strengths by combining the experimental branching fractions with radiative lifetimes reported in the literature and computed in this work. A hollow cathode discharge lamp was used to produce free atoms in the plasma and a Fourier transform spectrometer recorded the intensity-calibrated high-resolution spectra. In addition, we performed theoretical calculations using the multiconfiguration Hartree-Fock program ATSP2K. Results: This project provides a set of experimental and theoretical oscillator strengths. We derived 34 experimental oscillator strengths. Except from the Mg i optical triplet lines (3p 3P°0,1,2-4s 3S1), these oscillator strengths are measured for the first time. The theoretical oscillator strengths are in very good agreement with the experimental data and complement the missing transitions of the experimental data up to n = 7 from even and odd parity terms. We present an evaluated set of oscillator strengths, gf, with uncertainties as small as 5%. The new values of the Mg i optical triplet line (3p 3P°0,1,2-4s 3S1) oscillator strength values are 0.08 dex larger than the previous measurements.

  20. Analysis system for characterisation of simple, low-cost microfluidic components

    NASA Astrophysics Data System (ADS)

    Smith, Suzanne; Naidoo, Thegaran; Nxumalo, Zandile; Land, Kevin; Davies, Emlyn; Fourie, Louis; Marais, Philip; Roux, Pieter

    2014-06-01

    There is an inherent trade-off between cost and operational integrity of microfluidic components, especially when intended for use in point-of-care devices. We present an analysis system developed to characterise microfluidic components for performing blood cell counting, enabling the balance between function and cost to be established quantitatively. Microfluidic components for sample and reagent introduction, mixing and dispensing of fluids were investigated. A simple inlet port plugging mechanism is used to introduce and dispense a sample of blood, while a reagent is released into the microfluidic system through compression and bursting of a blister pack. Mixing and dispensing of the sample and reagent are facilitated via air actuation. For these microfluidic components to be implemented successfully, a number of aspects need to be characterised for development of an integrated point-of-care device design. The functional components were measured using a microfluidic component analysis system established in-house. Experiments were carried out to determine: 1. the force and speed requirements for sample inlet port plugging and blister pack compression and release using two linear actuators and load cells for plugging the inlet port, compressing the blister pack, and subsequently measuring the resulting forces exerted, 2. the accuracy and repeatability of total volumes of sample and reagent dispensed, and 3. the degree of mixing and dispensing uniformity of the sample and reagent for cell counting analysis. A programmable syringe pump was used for air actuation to facilitate mixing and dispensing of the sample and reagent. Two high speed cameras formed part of the analysis system and allowed for visualisation of the fluidic operations within the microfluidic device. Additional quantitative measures such as microscopy were also used to assess mixing and dilution accuracy, as well as uniformity of fluid dispensing - all of which are important requirements towards the

  1. A simple method of observation impact analysis for operational storm surge forecasting systems

    NASA Astrophysics Data System (ADS)

    Sumihar, Julius; Verlaan, Martin

    2016-04-01

    In this work, a simple method is developed for analyzing the impact of assimilating observations in improving forecast accuracy of a model. The method simply makes use of observation time series and the corresponding model output that are generated without data assimilation. These two time series are usually available in an operational database. The method is therefore easy to implement. Moreover, it can be used before actually implementing any data assimilation to the forecasting system. In this respect, it can be used as a tool for designing a data assimilation system, namely for searching for an optimal observing network. The method can also be used as a diagnostic tool, for example, for evaluating an existing operational data assimilation system to check if all observations are contributing positively to the forecast accuracy. The method has been validated with some twin experiments using a simple one-dimensional advection model as well as with an operational storm surge forecasting system based on the Dutch Continental Shelf model version 5 (DCSMv5). It has been applied for evaluating the impact of observations in the operational data assimilation system with DCSMv5 and for designing a data assimilation system for the new model DCSMv6. References: Verlaan, M. and J. Sumihar (2016), Observation impact analysis methods for storm surge forecasting systems, Ocean Dynamics, ODYN-D-15-00061R1 (in press) Zijl, F., J. Sumihar, and M. Verlaan (2015), Application of data assimilation for improved operational water level forecasting of the northwest European shelf and North Sea, Ocean Dynamics, 65, Issue 12, pp 1699-1716.

  2. A simple force-motion relation for migrating cells revealed by multipole analysis of traction stress.

    PubMed

    Tanimoto, Hirokazu; Sano, Masaki

    2014-01-07

    For biophysical understanding of cell motility, the relationship between mechanical force and cell migration must be uncovered, but it remains elusive. Since cells migrate at small scale in dissipative circumstances, the inertia force is negligible and all forces should cancel out. This implies that one must quantify the spatial pattern of the force instead of just the summation to elucidate the force-motion relation. Here, we introduced multipole analysis to quantify the traction stress dynamics of migrating cells. We measured the traction stress of Dictyostelium discoideum cells and investigated the lowest two moments, the force dipole and quadrupole moments, which reflect rotational and front-rear asymmetries of the stress field. We derived a simple force-motion relation in which cells migrate along the force dipole axis with a direction determined by the force quadrupole. Furthermore, as a complementary approach, we also investigated fine structures in the stress field that show front-rear asymmetric kinetics consistent with the multipole analysis. The tight force-motion relation enables us to predict cell migration only from the traction stress patterns.

  3. A simple and sensitive spectrofluorimetric method for analysis of some nitrofuran drugs in pharmaceutical preparations.

    PubMed

    Belal, Tarek Saied

    2008-09-01

    A simple, rapid, selective and sensitive spectrofluorimetric method was described for the analysis of three nitrofuran drugs, namely, nifuroxazide (NX), nitrofurantoin (NT) and nitrofurazone (NZ). The method involved the alkaline hydrolysis of the studied drugs by warming with 0.1 M sodium hydroxide solution then dilution with distilled water for NX or 2-propanol for NT and NZ. The formed fluorophores were measured at 465 nm (lambda (Ex) 265 nm), 458 nm (lambda (Ex) 245 nm) and 445 nm (lambda (Ex) 245 nm) for NX, NT and NZ, respectively. The reaction pathway was discussed and the structures of the fluorescent products were proposed. The different experimental parameters were studied and optimized. Regression analysis showed good correlation between fluorescence intensity and concentration over the ranges 0.08-1.00, 0.02-0.24 and 0.004-0.050 microg ml(-1) for NX, NT and NZ, respectively. The limits of detection of the method were 8.0, 1.9 and 0.3 ng ml(-1) for NX, NT and NZ, respectively. The proposed method was validated in terms of accuracy, precision and specificity, and it was successfully applied for the assay of the three nitrofurans in their different dosage forms. No interference was observed from common pharmaceutical adjuvants. The results were favorably compared with those obtained by reference spectrophotometric methods.

  4. Analysis of the genetic diversity of Lonicera japonica Thumb. using inter-simple sequence repeat markers.

    PubMed

    He, H Y; Zhang, D; Qing, H; Yang, Y

    2017-01-23

    Inter-simple sequence repeats (ISSRs) were used to analyze the genetic diversity of 21 accessions obtained from four provinces in China, Shandong, Henan, Hebei, and Sichuan. A total of 272 scored bands were generated using the eight primers previously screened across 21 accessions, of which 267 were polymorphic (98.16%). Genetic similarity coefficients varied from 0.4816 to 0.9118, with an average of 0.6337. The UPGMA dendrogram grouped 21 accessions into two main clusters. Cluster A comprised four Lonicera macranthoides Hand. Mazz. accessions, of which J10 was found to be from Sichuan, and J17, J18, and J19 were found to be from Shandong. Cluster B comprised 17 Lonicera japonica Thumb. accessions, divided into the wild accession J16 and the other 16 cultivars. The results of the principal component analysis were comparable to the cluster analysis. Therefore, the ISSR markers could be effectively used to distinguish interspecific and intraspecific variations, which may facilitate identification of Lonicera japonica cultivars for planting, medicinal use, and germplasm conservation.

  5. Analysis of the genetic diversity of beach plums by simple sequence repeat markers.

    PubMed

    Wang, X M; Wu, W L; Zhang, C H; Zhang, Y P; Li, W L; Huang, T

    2015-08-19

    The purpose of this study was to measure the genetic diversity of wild beach plum and cultivated species, and to determine the species relationships using SSRs markers. An analysis of genetic diversity from ten beach plum germplasms was carried out using 11 simple sequence repeat (SSR) primers selected from 35 primers to generate distinct PCR products. From this plant material, 44 allele variations were detected, with 3-5 alleles identified from each primer. The analysis showed that the genetic similarity coefficient varied from 0.721 ± 0.155 to 0.848 ± 0.136 within each of the ten beach plum germplasms and changed within the range of 0.551 ± 0.084 to 0.695 ± 0.073 between any two pairs of germplasms. According to the genetic dissimilarity coefficient matrix, a cluster analysis of SSRs using the unweighted pair group mean average method in the NTSYSpc 2.10 software revealed that the ten germplasms could be divided into two groups at the dissimilarity coefficient of 0.606. Class I included 77.8, 12.5, 30, and 33.3% of MM, MI, NY, and CM, respectively. Class II contains the remaining 9 beach plum germplasms. The markers generated by 11 SSR primers proved very effective in distinguishing the beach plum germplasm resources. It was clear that the geographical distribution did not correspond with the genetic relationships among the different beach plum strains. This result will be of value to beach plum breeding programs.

  6. Dream-reality confusion in borderline personality disorder: a theoretical analysis

    PubMed Central

    Skrzypińska, Dagna; Szmigielska, Barbara

    2015-01-01

    This paper presents an analysis of dream-reality confusion (DRC) in relation to the characteristics of borderline personality disorder (BPD), based on research findings and theoretical considerations. It is hypothesized that people with BPD are more likely to experience DRC compared to people in non-clinical population. Several variables related to this hypothesis were identified through a theoretical analysis of the scientific literature. Sleep disturbances: problems with sleep are found in 15–95.5% of people with BPD (Hafizi, 2013), and unstable sleep and wake cycles, which occur in BPD (Fleischer et al., 2012), are linked to DRC. Dissociation: nearly two-thirds of people with BPD experience dissociative symptoms (Korzekwa and Pain, 2009) and dissociative symptoms are correlated with a fantasy proneness; both dissociative symptoms and fantasy proneness are related to DRC (Giesbrecht and Merckelbach, 2006). Negative dream content: People with BPD have nightmares more often than other people (Semiz et al., 2008); dreams that are more likely to be confused with reality tend to be more realistic and unpleasant, and are reflected in waking behavior (Rassin et al., 2001). Cognitive disturbances: Many BPD patients experience various cognitive disturbances, including problems with reality testing (Fiqueierdo, 2006; Mosquera et al., 2011), which can foster DRC. Thin boundaries: People with thin boundaries are more prone to DRC than people with thick boundaries, and people with BPD tend to have thin boundaries (Hartmann, 2011). The theoretical analysis on the basis of these findings suggests that people who suffer from BPD may be more susceptible to confusing dream content with actual waking events. PMID:26441768

  7. Cepstral peak sensitivity: A theoretic analysis and comparison of several implementations

    PubMed Central

    Skowronski, Mark D.; Shrivastav, Rahul; Hunter, Eric J.

    2014-01-01

    Summary Objective The aim of this study was to develop a theoretic analysis of the cepstral peak, to compare several cepstral peak software programs, and to propose methods for reducing variability in cepstral peak estimation. Study Design Descriptive, experimental study. Methods The theoretic cepstral peak value of a pulse train was derived and compared to estimates computed for pulse train WAV files using available cepstral peak software programs: 1) Hillenbrand’s cepstral peak prominence (CPP) software, 2) KayPENTAX Multi-Speech implementation of CPP, and 3) a MATLAB implementation using cepstral interpolation. Cepstral peak variation was also investigated for synthetic breathy vowels. Results For pulse trains with period T samples, the theoretic cepstral peak is 1/2+ε/T, |ε|<0.1 for all pulse trains (ε=0 for integer T). For fundamental frequencies between 70 and 230 Hz, cepstral peak mean ± st. dev. was 0.496±0.002 using cepstral interpolation and 0.29±0.03 using Hillenbrand’s software, whereas CPP was 35.0±3.8 dB using Hillenbrand’s software and 20.5±2.7 dB using KayPENTAX’s software. CP and CPP vs. signal-to-noise ratio for synthetic breathy vowels were fit to a logistic model for the Hillenbrand (R2 = 0.92) and KayPENTAX (R2 = 0.82) estimators as well as an ideal estimator (R2 = 0.98) which used a period-synchronous analysis. Conclusions The findings indicate that several variables unrelated to the signal itself impact cepstral peak values, with some factors introducing large variability in cepstral peak values that would otherwise be attributed to the signal (e.g., voice quality). Variability may be reduced by using a period-synchronous analysis with Hann windows. PMID:25944288

  8. Theoretical analysis and experimental evaluation of a Csl(TI) based electronic portal imaging system.

    PubMed

    Sawant, Amit; Zeman, Herbert; Samant, Sanjiv; Lovhoiden, Gunnar; Weinberg, Brent; DiBianca, Frank

    2002-06-01

    This article discusses the design and analysis of a portal imaging system based on a thick transparent scintillator. A theoretical analysis using Monte Carlo simulation was performed to calculate the x-ray quantum detection efficiency (QDE), signal to noise ratio (SNR) and the zero frequency detective quantum efficiency [DQE(0)] of the system. A prototype electronic portal imaging device (EPID) was built, using a 12.7 mm thick, 20.32 cm diameter, Csl(Tl) scintillator, coupled to a liquid nitrogen cooled CCD TV camera. The system geometry of the prototype EPID was optimized to achieve high spatial resolution. The experimental evaluation of the prototype EPID involved the determination of contrast resolution, depth of focus, light scatter and mirror glare. Images of humanoid and contrast detail phantoms were acquired using the prototype EPID and were compared with those obtained using conventional and high contrast portal film and a commercial EPID. A theoretical analysis was also carried out for a proposed full field of view system using a large area, thinned CCD camera and a 12.7 mm thick CsI(TI) crystal. Results indicate that this proposed design could achieve DQE(0) levels up to 11%, due to its order of magnitude higher QDE compared to phosphor screen-metal plate based EPID designs, as well as significantly higher light collection compared to conventional TV camera based systems.

  9. Information-theoretic analysis of x-ray scatter and phase architectures for anomaly detection

    NASA Astrophysics Data System (ADS)

    Coccarelli, David; Gong, Qian; Stoian, Razvan-Ionut; Greenberg, Joel A.; Gehm, Michael E.; Lin, Yuzhang; Huang, Liang-Chih; Ashok, Amit

    2016-05-01

    Conventional performance analysis of detection systems confounds the effects of the system architecture (sources, detectors, system geometry, etc.) with the effects of the detection algorithm. Previously, we introduced an information-theoretic approach to this problem by formulating a performance metric, based on Cauchy-Schwarz mutual information, that is analogous to the channel capacity concept from communications engineering. In this work, we discuss the application of this metric to study novel screening systems based on x-ray scatter or phase. Our results show how effective use of this metric can impact design decisions for x-ray scatter and phase systems.

  10. Theoretical Analysis of Orientation Distribution Function Reconstruction of Textured Polycrystal by Parametric X-rays

    NASA Astrophysics Data System (ADS)

    Lobach, I.; Benediktovitch, A.

    2016-07-01

    The possibility of quantitative texture analysis by means of parametric x-ray radiation (PXR) from relativistic electrons with Lorentz factor γ > 50MeV in a polycrystal is considered theoretically. In the case of rather smooth orientation distribution function (ODF) and large detector (θD >> 1/γ) the universal relation between ODF and intensity distribution is presented. It is shown that if ODF is independent on one from Euler angles, then the texture is fully determined by angular intensity distribution. Application of the method to the simulated data shows the stability of the proposed algorithm.

  11. Analysis of poetic literature using B. F. Skinner's theoretical framework from verbal behavior

    PubMed Central

    Luke, Nicole M.

    2003-01-01

    This paper examines Skinner's work on verbal behavior in the context of literature as a particular class of written verbal behavior. It looks at contemporary literary theory and analysis and the contributions that Skinner's theoretical framework can make. Two diverse examples of poetic literature are chosen and analyzed following Skinner's framework, examining the dynamic interplay between the writer and reader that take place within the bounds of the work presented. It is concluded that Skinner's hypotheses about verbal behavior and the functional approach to understanding it have much to offer literary theorists in their efforts to understand literary works and should be more carefully examined.

  12. Morphology of synthetic chrysoberyl and alexandrite crystals: Analysis of experimental data and theoretical modeling

    NASA Astrophysics Data System (ADS)

    Gromalova, N. A.; Eremin, N. N.; Dorokhova, G. I.; Urusov, V. S.

    2012-07-01

    A morphological analysis of chrysoberyl and alexandrite crystals obtained by flux crystallization has been performed. Seven morphological types of crystals are selected. The surface energies of the faces of chrysoberyl and alexandrite crystals and their isostructural analogs, BeCr2O4 and BeFe2O4, have been calculated by atomistic computer modeling using the Metadise program. A "combined" approach is proposed which takes into account both the structural geometry and the surface energy of the faces and thus provides better agreement between the theoretical and experimentally observed faceting of chrysoberyl and alexandrite crystals.

  13. Adsorption and Coadsorption of CO and NO on the RH(100) Surface. A Theoretical Analysis

    DTIC Science & Technology

    1989-04-14

    AS RPT. QDTIC USERS unclassified 22a NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE nclu1e Area Code) 22c. OFFICE SYMBOL Roald Hoffmann 607-255-3419 00...Coadsorption of CO and 30 on the Rh (100) Surface: A Theoretical Analysis Dragan LJ. Vutkovi,&, Susan A. Jansen and Roald Hoffmann" Department of...Pirug, H.P. Bonzel, H. Hopster and H. Ibach, J. Chem. Phys. 1979, 71, 593. c) A.F. Carley, S. Rassias, M.W. Roberts and T.-H. Wang , Surf. Scl. 1979

  14. Theoretical conformational analysis of the bovine adrenal medulla 12 residue peptide molecule

    NASA Astrophysics Data System (ADS)

    Akhmedov, N. A.; Tagiyev, Z. H.; Hasanov, E. M.; Akverdieva, G. A.

    2003-02-01

    The spatial structure and conformational properties of the bovine adrenal medulla 12 residue peptide Tyr1-Gly2-Gly3-Phe4-Met5-Arg6-Arg7-Val8-Gly9-Arg10-Pro11-Glu12 (BAM-12P) molecule were studied by theoretical conformational analysis. It is revealed that this molecule can exist in several stable states. The energy and geometrical parameters for the low-energy conformations are obtained. The conformationally rigid and labile segments of this molecule were revealed.

  15. Feasibility of theoretical formulas on the anisotropy of shale based on laboratory measurement and error analysis

    NASA Astrophysics Data System (ADS)

    Xie, Jianyong; Di, Bangrang; Wei, Jianxin; Luan, Xinyuan; Ding, Pinbo

    2015-04-01

    This paper designs a total angle ultrasonic test method to measure the P-wave velocities (vp), vertically and horizontally polarized shear wave velocities (vsv and vsh) of all angles to the bedding plane on different kinds of strong anisotropic shale. Analysis has been made of the comparisons among the observations and corresponding calculated theoretical curves based on the varied vertical transversely isotropic (TI) medium theories, for which discussing the real similarity with the characterizations of the TI medium on the scope of dynamic behaviors, and further conclude a more accurate and precise theory from the varied theoretical formulas as well as its suitable range to characterize the strong anisotropy of shale. At a low phase angle (theta <10 degrees), the three theoretical curves are consistent with the observations, and then tend to be distinct with the increase of the phase angle, especially for the Thomsen theoretical curves which tend toward serious deviation, while the Berryman expressions provide a relatively much better agreement with the measured data for vp, vsv on shale. Also all of the three theories lead to more deviations in the approximation of the vsv than for the vp and vsh. Furthermore, we created synthetic comparative ideal physical models (from coarse bakelite, cambric bakelite, and paper bakelite) as supplementary models to natural shale, which are used to model shale with different anisotropy, to research the effects of the anisotropic parameters upon the applicability of the former optimal TI theories, especially for the vsv. We found the when the P-wave anisotropy, S-wave anisotropy ε, γ > 0.25, the Berrryman curve will be the best fit for the vp, vsv on shale.

  16. PLANS: A finite element program for nonlinear analysis of structures. Volume 1: Theoretical manual

    NASA Technical Reports Server (NTRS)

    Pifko, A.; Levine, H. S.; Armen, H., Jr.

    1975-01-01

    The PLANS system is described which is a finite element program for nonlinear analysis. The system represents a collection of special purpose computer programs each associated with a distinct physical problem class. Modules of PLANS specifically referenced and described in detail include: (1) REVBY, for the plastic analysis of bodies of revolution; (2) OUT-OF-PLANE, for the plastic analysis of 3-D built-up structures where membrane effects are predominant; (3) BEND, for the plastic analysis of built-up structures where bending and membrane effects are significant; (4) HEX, for the 3-D elastic-plastic analysis of general solids; and (5) OUT-OF-PLANE-MG, for material and geometrically nonlinear analysis of built-up structures. The SATELLITE program for data debugging and plotting of input geometries is also described. The theoretical foundations upon which the analysis is based are presented. Discussed are the form of the governing equations, the methods of solution, plasticity theories available, a general system description and flow of the programs, and the elements available for use.

  17. Dependence of velocity fluctuations on solar wind speeds: A simple analysis with IPS method

    NASA Technical Reports Server (NTRS)

    Misawa, H.; Kojima, M.

    1995-01-01

    A number of theoretical works have suggested that MHD plasma fluctuations in solar winds should play an important role particularly in the acceleration of high speed winds inside or near 0.1 AU from the sun. Since velocity fluctuations in solar winds are expected to be caused by the MHD plasma fluctuations, measurements of the velocity fluctuations give clues to reveal the acceleration process of solar winds. We made interplanetary scintillation (IPS) observations at the region out of 0.1 AU to investigate dependence of velocity fluctuations on flow speeds. For evaluating the velocity fluctuation of a flow, we selected the IPS data-set acquired at 2 separate antennas which located in the projected flow direction onto the baseline plane, and tried to compare skewness of the observed cross correlation function(CCF) with skewness of modeled CCFs in which velocity fluctuations were parametrized. The integration effect of IPS along a ray path was also taken into account in the estimation of modeled CCFs. Although this analysis method is significant to derive only parallel fluctuation components to the flow directions, preliminary analyses show following results: (1) High speed winds (Vsw greater than or equal to 500 km/s out of 0.3 AU) indicate enhancement of velocity fluctuations near 0.1 AU; and (2) Low speed winds (Vsw less than or equal to 400 Km/s out of 0.3 AU) indicate small velocity fluctuations at any distances.

  18. Spectroscopic and theoretical analysis of Pd2+-Cl--H2O system

    NASA Astrophysics Data System (ADS)

    Podborska, Agnieszka; Wojnicki, Marek

    2017-01-01

    Time dependent density functional theory (TD-DFT) and spectrophotometric methods were used for speciation analysis in Pd2+-Cl--H2O system. It was shown, that there is an excellent harmony between TD-DFT calculated UV-VIS spectra end those registered using spectrophotometric method. It was shown, that for simple electrolyte, a several different form of Pd(II) appears simultaneously. Thanks to TD-DFT method, it was possible to deconvolution experimental UV-VIS spectrum and determination which form of Pd(II) complexes are present in the solution.

  19. Theoretical analysis of coverage-dependent rotational hindrance of PF 3 adsorbed on Ru(001)

    NASA Astrophysics Data System (ADS)

    Kaji, H.; Kakitani, K.; Yagi, Y.; Yoshimori, A.

    1996-08-01

    Distribution of the azimuthal orientation of PF 3 molecules adsorbed on Ru(001) measured by ESDIAD shows interesting temperature and coverage dependences. It is interpreted in this analysis as due to the short range order in the locative distribution of the PF 3 molecules. Monte Carlo simulations are performed to obtain the temperature and coverage-dependent distribution of the adsorbed molecules. The distribution of the azimuthal orientation of the molecule is discussed on the basis of the obtained locative distribution of the molecules by using simple models for rotational hindrance to be compared with the experimental results.

  20. Modeling and analysis of smart piezoelectric beams using simple higher order shear deformation theory

    NASA Astrophysics Data System (ADS)

    Adnan Elshafei, M.; Alraiess, Fuzy

    2013-03-01

    In the current work, a finite element formulation is developed for modeling and analysis of isotropic as well as orthotropic composite beams with distributed piezoelectric actuators subjected to both mechanical and electrical loads. The proposed model is developed based on a simple higher order shear deformation theory where the displacement field equations in the model account for a parabolic distribution of the shear strain and the nonlinearity of in-plane displacements across the thickness and subsequently the shear correction factor is not involved. The virtual displacement method is used to formulate the equations of motion of the structure system. The model is valid for both segmented and continuous piezoelectric elements, which can be either surface bonded or embedded in the laminated beams. A two-node element with four mechanical degrees of freedom in addition to one electrical degree of freedom for each node is used in the finite element formulation. The electric potential is considered as a function of the thickness and the length of the beam element. A MATLAB code is developed to compute the static deformation and free vibration parameters of the beams with distributed piezoelectric actuators. The obtained results from the proposed model are compared with the available analytical results and the finite element results of other researchers.

  1. Survey and analysis of simple sequence repeats (SSRs) in three genomes of Candida species.

    PubMed

    Jia, Dongmei

    2016-06-15

    Simple sequence repeats (SSRs) or microsatellites, which composed of tandem repeated short units of 1-6 bp, have been paying attention continuously. Here, the distribution, composition and polymorphism of microsatellites and compound microsatellites were analyzed in three available genomes of Candida species (Candida dubliniensis, Candida glabrata and Candida orthopsilosis). The results show that there were 118,047, 66,259 and 61,119 microsatellites in genomes of C. dubliniensis, C. glabrata and C. orthopsilosis, respectively. The SSRs covered more than 1/3 length of genomes in the three species. The microsatellites, which just consist of bases A and (or) T, such as (A)n, (T)n, (AT)n, (TA)n, (AAT)n, (TAA)n, (TTA)n, (ATA)n, (ATT)n and (TAT)n, were predominant in the three genomes. The length of microsatellites was focused on 6 bp and 9 bp either in the three genomes or in its coding sequences. What's more, the relative abundance (19.89/kbp) and relative density (167.87 bp/kbp) of SSRs in sequence of mitochondrion of C. glabrata were significantly great than that in any one of genomes or chromosomes of the three species. In addition, the distance between any two adjacent microsatellites was an important factor to influence the formation of compound microsatellites. The analysis may be helpful for further studying the roles of microsatellites in genomes' origination, organization and evolution of Candida species.

  2. Genetic diversity analysis of okra (Abelmoschus esculentus L.) by inter-simple sequence repeat (ISSR) markers.

    PubMed

    Yuan, C Y; Zhang, C; Wang, P; Hu, S; Chang, H P; Xiao, W J; Lu, X T; Jiang, S B; Ye, J Z; Guo, X H

    2014-04-25

    Okra (Abelmoschus esculentus L.) is not only a nutrient-rich vegetable but also an important medicinal herb. Inter-simple sequence repeat (ISSR) markers were employed to investigate the genetic diversity and differentiation of 24 okra genotypes. In this study, the PCR products were separated by electrophoresis on 8% nondenaturing polyacrylamide gel and visualized by silver staining. The 22 ISSR primers produced 289 amplified DNA fragments, and 145 (50%) fragments were polymorphic. The 289 markers were used to construct the dendrogram based on the unweighted pair-group method with arithmetic average (UPGMA) cluster analysis. The dendrogram indicated that 24 okras were clustered into 4 geographically distinct groups. The average polymorphism information content (PIC) was 0.531929, which showed that the majority of primers were informative. The high values of allele frequency, genetic diversity, and heterozygosity showed that primer-sample combinations produced measurable fragments. The mean distances ranged from 0.045455 to 0.454545. The dendrogram indicated that the ISSR markers succeeded in distinguishing most of the 24 varieties in relation to their genetic backgrounds and geographical origins.

  3. Final Analysis and Results of the Phase II SIMPLE Dark Matter Search

    NASA Astrophysics Data System (ADS)

    Felizardo, M.; Girard, T. A.; Morlat, T.; Fernandes, A. C.; Ramos, A. R.; Marques, J. G.; Kling, A.; Puibasset, J.; Auguste, M.; Boyer, D.; Cavaillou, A.; Poupeney, J.; Sudre, C.; Miley, H. S.; Payne, R. F.; Carvalho, F. P.; Prudêncio, M. I.; Gouveia, A.; Marques, R.

    2012-05-01

    We report the final results of the Phase II SIMPLE measurements, comprising two run stages of 15 superheated droplet detectors each, with the second stage including an improved neutron shielding. The analyses include a refined signal analysis, and revised nucleation efficiency based on a reanalysis of previously reported monochromatic neutron irradiations. The combined results yield a contour minimum of σp=5.7×10-3pb at 35GeV/c2 in the spin-dependent sector of weakly interacting massive particle (WIMP) proton interactions, the most restrictive to date for MW≤60GeV/c2 from a direct search experiment and overlapping, for the first time, with results previously obtained only indirectly. In the spin-independent sector, a minimum of 4.7×10-6pb at 35GeV/c2 is achieved, with the exclusion contour challenging a significant part of the light mass WIMP region of current interest.

  4. The beauty of simple adaptive control and new developments in nonlinear systems stability analysis

    SciTech Connect

    Barkana, Itzhak

    2014-12-10

    Although various adaptive control techniques have been around for a long time and in spite of successful proofs of stability and even successful demonstrations of performance, the eventual use of adaptive control methodologies in practical real world systems has met a rather strong resistance from practitioners and has remained limited. Apparently, it is difficult to guarantee or even understand the conditions that can guarantee stable operations of adaptive control systems under realistic operational environments. Besides, it is difficult to measure the robustness of adaptive control system stability and allow it to be compared with the common and widely used measure of phase margin and gain margin that is utilized by present, mainly LTI, controllers. Furthermore, customary stability analysis methods seem to imply that the mere stability of adaptive systems may be adversely affected by any tiny deviation from the pretty idealistic and assumably required stability conditions. This paper first revisits the fundamental qualities of customary direct adaptive control methodologies, in particular the classical Model Reference Adaptive Control, and shows that some of their basic drawbacks have been addressed and eliminated within the so-called Simple Adaptive Control methodology. Moreover, recent developments in the stability analysis methods of nonlinear systems show that prior conditions that were customarily assumed to be needed for stability are only apparent and can be eliminated. As a result, sufficient conditions that guarantee stability are clearly stated and lead to similarly clear proofs of stability. As many real-world applications show, once robust stability of the adaptive systems can be guaranteed, the added value of using Add-On Adaptive Control along with classical Control design techniques is pushing the desired performance beyond any previous limits.

  5. The beauty of simple adaptive control and new developments in nonlinear systems stability analysis

    NASA Astrophysics Data System (ADS)

    Barkana, Itzhak

    2014-12-01

    Although various adaptive control techniques have been around for a long time and in spite of successful proofs of stability and even successful demonstrations of performance, the eventual use of adaptive control methodologies in practical real world systems has met a rather strong resistance from practitioners and has remained limited. Apparently, it is difficult to guarantee or even understand the conditions that can guarantee stable operations of adaptive control systems under realistic operational environments. Besides, it is difficult to measure the robustness of adaptive control system stability and allow it to be compared with the common and widely used measure of phase margin and gain margin that is utilized by present, mainly LTI, controllers. Furthermore, customary stability analysis methods seem to imply that the mere stability of adaptive systems may be adversely affected by any tiny deviation from the pretty idealistic and assumably required stability conditions. This paper first revisits the fundamental qualities of customary direct adaptive control methodologies, in particular the classical Model Reference Adaptive Control, and shows that some of their basic drawbacks have been addressed and eliminated within the so-called Simple Adaptive Control methodology. Moreover, recent developments in the stability analysis methods of nonlinear systems show that prior conditions that were customarily assumed to be needed for stability are only apparent and can be eliminated. As a result, sufficient conditions that guarantee stability are clearly stated and lead to similarly clear proofs of stability. As many real-world applications show, once robust stability of the adaptive systems can be guaranteed, the added value of using Add-On Adaptive Control along with classical Control design techniques is pushing the desired performance beyond any previous limits.

  6. Finite-fault source inversion using teleseismic P waves: Simple parameterization and rapid analysis

    USGS Publications Warehouse

    Mendoza, C.; Hartzell, S.

    2013-01-01

    We examine the ability of teleseismic P waves to provide a timely image of the rupture history for large earthquakes using a simple, 2D finite‐fault source parameterization. We analyze the broadband displacement waveforms recorded for the 2010 Mw∼7 Darfield (New Zealand) and El Mayor‐Cucapah (Baja California) earthquakes using a single planar fault with a fixed rake. Both of these earthquakes were observed to have complicated fault geometries following detailed source studies conducted by other investigators using various data types. Our kinematic, finite‐fault analysis of the events yields rupture models that similarly identify the principal areas of large coseismic slip along the fault. The results also indicate that the amount of stabilization required to spatially smooth the slip across the fault and minimize the seismic moment is related to the amplitudes of the observed P waveforms and can be estimated from the absolute values of the elements of the coefficient matrix. This empirical relationship persists for earthquakes of different magnitudes and is consistent with the stabilization constraint obtained from the L‐curve in Tikhonov regularization. We use the relation to estimate the smoothing parameters for the 2011 Mw 7.1 East Turkey, 2012 Mw 8.6 Northern Sumatra, and 2011 Mw 9.0 Tohoku, Japan, earthquakes and invert the teleseismic P waves in a single step to recover timely, preliminary slip models that identify the principal source features observed in finite‐fault solutions obtained by the U.S. Geological Survey National Earthquake Information Center (USGS/NEIC) from the analysis of body‐ and surface‐wave data. These results indicate that smoothing constraints can be estimated a priori to derive a preliminary, first‐order image of the coseismic slip using teleseismic records.

  7. Charge tunneling across strongly inhomogeneous potential barriers in metallic heterostructures: A simplified theoretical analysis and possible experimental tests

    NASA Astrophysics Data System (ADS)

    Belogolovskii, Mikhail

    2014-09-01

    Universal aspects of the charge transport through strongly disordered potential barriers in metallic heterojunctions are analyzed. A simple theoretical formalism for two kinds of transmission probability distribution functions valid for smooth tunneling barriers and those with abrupt boundaries is presented. We argue that their universality has simple mathematical origin and can arise in totally different physical contexts. Finally, we analyze possible applications of superconducting junctions to test the universality of transport characteristics in structurally disordered insulating films without any fitting parameters and point out that the proposed approach can be useful in understanding the dynamics of surface screening currents in superconductors with an inhomogeneous near-surface region.

  8. Growth and spectral analysis of piperazinium L-tartrate salt: A combined experimental and theoretical approach

    NASA Astrophysics Data System (ADS)

    Mathammal, R.; Sudha, N.; Shankar, R.; Rajaboopathi, M.; Janagi, S.; Prabavathi, B.

    2017-03-01

    This report discusses crystal structure, molecular arrangements, vibrational analysis, UV-Vis-NIR spectrum, fluorescence emission and second harmonic generation (SHG) efficiency of piperazinium L-tartrate (PPZ2+·Tart2-) crystals with the support of theoretical analysis. A good optical quality PPZ2+·Tart2- crystals were grown from slow evaporation of aqueous solution. The PPZ2+·Tart2- crystal belongs to monoclinic system with non-centrosymmetric space group P21. The charge transfer from donor to acceptor moieties and corresponding changes in the bond lengths and bond angles have been observed. The observed functional group vibrations in the experimental FTIR and the Raman spectrum were assigned and compared with theoretical wavenumbers of PPZ2+·Tart2-.The electron distribution on the donor and acceptor in PPZ2+·Tart2- has been clearly visualised using molecular electrostatic potential map. Compared with L-tartaric acid, red shift was observed in absorption and fluorescence spectrum. The low value of dielectric constant and dielectric loss at the higher frequency and its high second harmonic efficiency suggest PPZ2+·Tart2- crystal is less defect free and suitable for NLO applications.

  9. A thematic analysis of theoretical models for translational science in nursing: mapping the field.

    PubMed

    Mitchell, Sandra A; Fisher, Cheryl A; Hastings, Clare E; Silverman, Leanne B; Wallen, Gwenyth R

    2010-01-01

    The quantity and diversity of conceptual models in translational science may complicate rather than advance the use of theory. This paper offers a comparative thematic analysis of the models available to inform knowledge development, transfer, and utilization. Literature searches identified 47 models for knowledge translation. Four thematic areas emerged: (1) evidence-based practice and knowledge transformation processes, (2) strategic change to promote adoption of new knowledge, (3) knowledge exchange and synthesis for application and inquiry, and (4) designing and interpreting dissemination research. This analysis distinguishes the contributions made by leaders and researchers at each phase in the process of discovery, development, and service delivery. It also informs the selection of models to guide activities in knowledge translation. A flexible theoretical stance is essential to simultaneously develop new knowledge and accelerate the translation of that knowledge into practice behaviors and programs of care that support optimal patient outcomes.

  10. A Thematic Analysis of Theoretical Models for Translational Science in Nursing: Mapping the Field

    PubMed Central

    Mitchell, Sandra A.; Fisher, Cheryl A.; Hastings, Clare E.; Silverman, Leanne B.; Wallen, Gwenyth R.

    2010-01-01

    Background The quantity and diversity of conceptual models in translational science may complicate rather than advance the use of theory. Purpose This paper offers a comparative thematic analysis of the models available to inform knowledge development, transfer, and utilization. Method Literature searches identified 47 models for knowledge translation. Four thematic areas emerged: (1) evidence-based practice and knowledge transformation processes; (2) strategic change to promote adoption of new knowledge; (3) knowledge exchange and synthesis for application and inquiry; (4) designing and interpreting dissemination research. Discussion This analysis distinguishes the contributions made by leaders and researchers at each phase in the process of discovery, development, and service delivery. It also informs the selection of models to guide activities in knowledge translation. Conclusions A flexible theoretical stance is essential to simultaneously develop new knowledge and accelerate the translation of that knowledge into practice behaviors and programs of care that support optimal patient outcomes. PMID:21074646

  11. Elastic responses of underground circular arches considering dynamic soil-structure interaction: A theoretical analysis

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Long; Jin, Feng-Nian; Fan, Hua-Lin

    2013-02-01

    Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equation of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal superposition. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.

  12. Theoretical and experimental analysis of bispectrum of vibration signals for fault diagnosis of gears

    NASA Astrophysics Data System (ADS)

    Guoji, Shen; McLaughlin, Stephen; Yongcheng, Xu; White, Paul

    2014-02-01

    Condition monitoring and fault diagnosis is an important issue for gearbox maintenance and safety. The critical process involved in such activities is to extract reliable features representative of the condition of the gears or gearbox. In this paper a framework is presented for the application of bispectrum to the analysis of gearbox vibration. The bispectrum of a composite signal consisting of multiple periodic components has peaks at the bifrequencies that correspond to closely related components which can be produced by any nonlinearity. As a result, biphase verification is necessary to decrease false-alarming for any bispectrum-based method. A model based on modulated signals is adopted to reveal the bispectrum characteristics for the vibration of a faulty gear, and the corresponding amplitude and phase of the bispectrum expression are deduced. Therefore, a diagnostic approach based on the theoretical result is derived and verified by the analysis of a set of vibration signals from a helicopter gearbox.

  13. NDARC-NASA Design and Analysis of Rotorcraft Theoretical Basis and Architecture

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2010-01-01

    The theoretical basis and architecture of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are described. The principal tasks of NDARC are to design (or size) a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated. The aircraft attributes are obtained from the sum of the component attributes. NDARC provides a capability to model general rotorcraft configurations, and estimate the performance and attributes of advanced rotor concepts. The software has been implemented with low-fidelity models, typical of the conceptual design environment. Incorporation of higher-fidelity models will be possible, as the architecture of the code accommodates configuration flexibility, a hierarchy of models, and ultimately multidisciplinary design, analysis and optimization.

  14. Performance of the Tariff Method: validation of a simple additive algorithm for analysis of verbal autopsies

    PubMed Central

    2011-01-01

    Background Verbal autopsies provide valuable information for studying mortality patterns in populations that lack reliable vital registration data. Methods for transforming verbal autopsy results into meaningful information for health workers and policymakers, however, are often costly or complicated to use. We present a simple additive algorithm, the Tariff Method (termed Tariff), which can be used for assigning individual cause of death and for determining cause-specific mortality fractions (CSMFs) from verbal autopsy data. Methods Tariff calculates a score, or "tariff," for each cause, for each sign/symptom, across a pool of validated verbal autopsy data. The tariffs are summed for a given response pattern in a verbal autopsy, and this sum (score) provides the basis for predicting the cause of death in a dataset. We implemented this algorithm and evaluated the method's predictive ability, both in terms of chance-corrected concordance at the individual cause assignment level and in terms of CSMF accuracy at the population level. The analysis was conducted separately for adult, child, and neonatal verbal autopsies across 500 pairs of train-test validation verbal autopsy data. Results Tariff is capable of outperforming physician-certified verbal autopsy in most cases. In terms of chance-corrected concordance, the method achieves 44.5% in adults, 39% in children, and 23.9% in neonates. CSMF accuracy was 0.745 in adults, 0.709 in children, and 0.679 in neonates. Conclusions Verbal autopsies can be an efficient means of obtaining cause of death data, and Tariff provides an intuitive, reliable method for generating individual cause assignment and CSMFs. The method is transparent and flexible and can be readily implemented by users without training in statistics or computer science. PMID:21816107

  15. Genetic diversity analysis of Bt cotton genotypes in Pakistan using simple sequence repeat markers.

    PubMed

    Ullah, I; Iram, A; Iqbal, M Z; Nawaz, M; Hasni, S M; Jamil, S

    2012-03-14

    The popularity of genetically modified insect resistant (Bt) cotton has promoted large scale monocultures, which is thought to worsen the problem of crop genetic homogeneity. Information on genetic diversity among Bt cotton varieties is lacking. We evaluated genetic divergence among 19 Bt cotton genotypes using simple sequence repeat (SSR) markers. Thirty-seven of 104 surveyed primers were found informative. Fifty-two primers selected on the basis of reported intra-hirsutum polymorphism in a cotton marker database showed a high degree of polymorphism, 56% compared to 13% for randomly selected primers. A total of 177 loci were amplified, with an average of 1.57 loci per primer, generating 38 markers. The amplicons ranged in size from 98 to 256 bp. The genetic similarities among the 19 genotypes ranged from 0.902 to 0.982, with an average of 0.947, revealing a lack of diversity. Similarities among genotypes from public sector organizations were higher than genotypes developed by private companies. Hybrids were found to be more distant compared to commercial cultivars and advanced breeding lines. Cluster analysis grouped the 19 Bt cotton genotypes into three major clusters and two independent entries. Cultivars IR-3701, Ali Akbar-802 and advanced breeding line VH-259 grouped in subcluster B2, with very narrow genetic distances despite dissimilar parentage. We found a very high level of similarity among Pakistani-bred Bt cotton varieties, which means that genetically diverse recurrent parents should be included to enhance genetic diversity. The intra-hirsutum polymorphic SSRs were found to be highly informative for molecular genetic diversity studies in these cotton varieties.

  16. Palaeomagnetic analysis of plunging fold structures: Errors and a simple fold test

    NASA Astrophysics Data System (ADS)

    Stewart, Simon A.

    1995-02-01

    The conventional corrections for bedding dip in palaeomagnetic studies involve either untilting about strike or about some inclined axis—the choice is usually governed by the perceived fold hinge orientation. While it has been recognised that untilting bedding about strike can be erroneous if the beds lie within plunging fold structures, there are several types of fold which have plunging hinges, but whose limbs have rotated about horizontal axes. Examples are interference structures and forced folds; restoration about inclined axes may be incorrect in these cases. The angular errors imposed upon palaeomagnetic lineation data via the wrong choice of rotation axis during unfolding are calculated here and presented for lineations in any orientation which could be associated with an upright, symmetrical fold. This extends to palaeomagnetic data previous analyses which were relevant to bedding-parallel lineations. This numerical analysis highlights the influence of various parameters which describe fold geometry and relative lineation orientation upon the angular error imparted to lineation data by the wrong unfolding method. The effect of each parameter is described, and the interaction of the parameters in producing the final error is discussed. Structural and palaeomagnetic data are cited from two field examples of fold structures which illustrate the alternative kinematic histories. Both are from thin-skinned thrust belts, but the data show that one is a true plunging fold, formed by rotation about its inclined hinge, whereas the other is an interference structure produced by rotation of the limbs about non-parallel horizontal axes. Since the angle between the palaeomagnetic lineations and the inclined fold hinge is equal on both limbs in the former type of structure, but varies from limb to limb in the latter, a simple test can be defined which uses palaeomagnetic lineation data to identify rotation axes and hence fold type. This test can use pre- or syn

  17. A Simple Exact Error Rate Analysis for DS-CDMA with Arbitrary Pulse Shape in Flat Nakagami Fading

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammad Azizur; Sasaki, Shigenobu; Kikuchi, Hisakazu; Harada, Hiroshi; Kato, Shuzo

    A simple exact error rate analysis is presented for random binary direct sequence code division multiple access (DS-CDMA) considering a general pulse shape and flat Nakagami fading channel. First of all, a simple model is developed for the multiple access interference (MAI). Based on this, a simple exact expression of the characteristic function (CF) of MAI is developed in a straight forward manner. Finally, an exact expression of error rate is obtained following the CF method of error rate analysis. The exact error rate so obtained can be much easily evaluated as compared to the only reliable approximate error rate expression currently available, which is based on the Improved Gaussian Approximation (IGA).

  18. Inter simple sequence repeat (ISSR) analysis of genetic diversity in tef [Eragrostis tef (Zucc.) Trotter].

    PubMed

    Assefa, Kebebew; Merker, Arnulf; Tefera, Hailu

    2003-01-01

    The DNA polymorphism among 92 selected tef genotypes belonging to eight origin groups was assessed using eight inter simple sequence repeat (ISSR) primers. The objectives were to examine the possibility of using ISSR markers for unravelling genetic diversity in tef, and to assess the extent and pattern of genetic diversity in the test germplasm with respect to origin groups. The eight primers were able to separate or distinguish all of the 92 tef genotypes based on a total of 110 polymorphic bands among the test lines. The Jaccard similarity coefficient among the test genotypes ranged from 0.26 to 0.86, and at about 60 % similarity level the clustering of this matrix using the unweighted pair-group method based on arithmetic average (UPGMA) resulted in the formation of six major clusters of 2 to 37 lines with further eight lines remaining ungrouped. The standardized Nei genetic distance among the eight groups of origin ranged between 0.03 and 0.32. The UPGMA clustering using the standardized genetic distance matrix resulted in the identification of three clusters of the eight groups of origin with bootstrap values ranging from 56 to 97. The overall mean Shannon Weaver diversity index of the test lines was 0.73, indicating better resolution of genetic diversity in tef with ISSR markers than with phenotypic (morphological) traits used in previous studies. This can be attributed mainly to the larger number of loci generated for evaluation with ISSR analysis as compared to the few number of phenotypic traits amenable for assessment and which are further greatly affected by environment and genotype x environment interaction. Analysis of variance of mean Shannon Weaver diversity indices revealed substantial (P < or = 0.05) variation in the level of diversity among the eight groups of origin. In conclusion, our results indicate that ISSR can be useful as DNA-based molecular markers for studying genetic diversity and phylogenetic relationships, DNA fingerprinting for the

  19. Predominant information quality scheme for the essential amino acids: an information-theoretical analysis.

    PubMed

    Esquivel, Rodolfo O; Molina-Espíritu, Moyocoyani; López-Rosa, Sheila; Soriano-Correa, Catalina; Barrientos-Salcedo, Carolina; Kohout, Miroslav; Dehesa, Jesús S

    2015-08-24

    In this work we undertake a pioneer information-theoretical analysis of 18 selected amino acids extracted from a natural protein, bacteriorhodopsin (1C3W). The conformational structures of each amino acid are analyzed by use of various quantum chemistry methodologies at high levels of theory: HF, M062X and CISD(Full). The Shannon entropy, Fisher information and disequilibrium are determined to grasp the spatial spreading features of delocalizability, order and uniformity of the optimized structures. These three entropic measures uniquely characterize all amino acids through a predominant information-theoretic quality scheme (PIQS), which gathers all chemical families by means of three major spreading features: delocalization, narrowness and uniformity. This scheme recognizes four major chemical families: aliphatic (delocalized), aromatic (delocalized), electro-attractive (narrowed) and tiny (uniform). All chemical families recognized by the existing energy-based classifications are embraced by this entropic scheme. Finally, novel chemical patterns are shown in the information planes associated with the PIQS entropic measures.

  20. Aerosol rebreathing method for assessment of airway abnormalities: theoretical analysis and validation.

    PubMed

    Kim, C S; Brown, L K; Lewars, G G; Sackner, M A

    1983-05-01

    An aerosol rebreathing method which determines total aerosol deposition in the lung by rebreathing non-radioactive inert aerosol was investigated theoretically for its performance characteristics. The method was then validated experimentally by examining a system response to various operating parameters, its reproducibility and convenience in clinical use. It was found from the theoretical analysis that an optimum performance would be achieved by breathing an aerosol of particles 1 micrometer in diameter with a 500-cm3 tidal volume at the breathing rate of 30 breaths/min. With these optimum parameters, experimental results of 10 normals and 10 patients with obstructive airway disease revealed an excellent measurement reproducibility within subjects (+/- 10% from means). There was a wide separation between the two groups in terms of number of rebreathing breaths to reach 90% aerosol deposition (N90) (mean +/- S.E. = 10.8 +/- 1.6 for normals vs. 3.9 +/- 1.1 for patients) and cumulative percentage of aerosol deposition at the fourth breath (AD4) (mean +/- S.E. = 68 +/- 4.4% for normals vs. 90 +/- 3.5% for patients).

  1. Theoretical Analysis of Triple Liquid Stub Tuner Impedance Matching for ICRH on Tokamaks

    NASA Astrophysics Data System (ADS)

    Du, Dan; Gong, Xueyu; Yin, Lan; Xiang, Dong; Li, Jingchun

    2015-12-01

    The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating (ICRH) antennae with high power injection into plasmas. A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors. This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions. The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution. Then, the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions. The method provides an alternative theoretical method, rather than measurements, to study triple liquid stub tuner impedance matching for ICRH, which may be beneficial for the design of ICRH systems on tokamaks. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2014GB108002, 2013GB107001), National Natural Science Foundation of China (Nos. 11205086, 11205053, 11375085, and 11405082), the Construct Program of Fusion and Plasma Physics Innovation Team in Hunan Province, China (No. NHXTD03), the Natural Science Foundation of Hunan Province, China (No. 2015JJ4044)

  2. Limitations of the spike-triggered averaging for estimating motor unit twitch force: a theoretical analysis.

    PubMed

    Negro, Francesco; Yavuz, Ş Utku; Yavuz, Utku Ş; Farina, Dario

    2014-01-01

    Contractile properties of human motor units provide information on the force capacity and fatigability of muscles. The spike-triggered averaging technique (STA) is a conventional method used to estimate the twitch waveform of single motor units in vivo by averaging the joint force signal. Several limitations of this technique have been previously discussed in an empirical way, using simulated and experimental data. In this study, we provide a theoretical analysis of this technique in the frequency domain and describe its intrinsic limitations. By analyzing the analytical expression of STA, first we show that a certain degree of correlation between the motor unit activities prevents an accurate estimation of the twitch force, even from relatively long recordings. Second, we show that the quality of the twitch estimates by STA is highly related to the relative variability of the inter-spike intervals of motor unit action potentials. Interestingly, if this variability is extremely high, correct estimates could be obtained even for high discharge rates. However, for physiological inter-spike interval variability and discharge rate, the technique performs with relatively low estimation accuracy and high estimation variance. Finally, we show that the selection of the triggers that are most distant from the previous and next, which is often suggested, is not an effective way for improving STA estimates and in some cases can even be detrimental. These results show the intrinsic limitations of the STA technique and provide a theoretical framework for the design of new methods for the measurement of motor unit force twitch.

  3. Combined Theoretical and Experimental Analysis of Processes Determining Cathode Performance in Solid Oxide Fuel Cells

    SciTech Connect

    Kukla, Maija M.; Kotomin, Eugene Alexej; Merkle, R.; Mastrikov, Yuri; Maier, J.

    2013-02-11

    Solid oxide fuel cells (SOFC) are under intensive investigation since the 1980’s as these devices open the way for ecologically clean direct conversion of the chemical energy into electricity, avoiding the efficiency limitation by Carnot’s cycle for thermochemical conversion. However, the practical development of SOFC faces a number of unresolved fundamental problems, in particular concerning the kinetics of the electrode reactions, especially oxygen reduction reaction. We review recent experimental and theoretical achievements in the current understanding of the cathode performance by exploring and comparing mostly three materials: (La,Sr)MnO3 (LSM), (La,Sr)(Co,Fe)O3 (LSCF) and (Ba,Sr)(Co,Fe)O3 (BSCF). Special attention is paid to a critical evaluation of advantages and disadvantages of BSCF, which shows the best cathode kinetics known so far for oxides. We demonstrate that it is the combined experimental and theoretical analysis of all major elementary steps of the oxygen reduction reaction which allows us to predict the rate determining steps for a given material under specific operational conditions and thus control and improve SOFC performance.

  4. Combined theoretical and experimental analysis of processes determining cathode performance in solid oxide fuel cells.

    PubMed

    Kuklja, M M; Kotomin, E A; Merkle, R; Mastrikov, Yu A; Maier, J

    2013-04-21

    Solid oxide fuel cells (SOFC) are under intensive investigation since the 1980's as these devices open the way for ecologically clean direct conversion of the chemical energy into electricity, avoiding the efficiency limitation by Carnot's cycle for thermochemical conversion. However, the practical development of SOFC faces a number of unresolved fundamental problems, in particular concerning the kinetics of the electrode reactions, especially oxygen reduction reaction. We review recent experimental and theoretical achievements in the current understanding of the cathode performance by exploring and comparing mostly three materials: (La,Sr)MnO3 (LSM), (La,Sr)(Co,Fe)O3 (LSCF) and (Ba,Sr)(Co,Fe)O3 (BSCF). Special attention is paid to a critical evaluation of advantages and disadvantages of BSCF, which shows the best cathode kinetics known so far for oxides. We demonstrate that it is the combined experimental and theoretical analysis of all major elementary steps of the oxygen reduction reaction which allows us to predict the rate determining steps for a given material under specific operational conditions and thus control and improve SOFC performance.

  5. Genome wide characterization of simple sequence repeats in watermelon genome and their application in comparative mapping and genetic diversity analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple sequence repeats (SSR) or microsatellite markers are one of the most informative and versatile DNA-based markers. The use of next-generation sequencing technologies allow whole genome sequencing and make it possible to develop large numbers of SSRs through bioinformatic analysis of genome da...

  6. Theoretical and experimental examination of SFG polarization analysis at acetonitrile-water solution surfaces.

    PubMed

    Saito, Kengo; Peng, Qiling; Qiao, Lin; Wang, Lin; Joutsuka, Tatsuya; Ishiyama, Tatsuya; Ye, Shen; Morita, Akihiro

    2017-03-16

    Sum frequency generation (SFG) spectroscopy is widely used to observe molecular orientation at interfaces through a combination of various types of polarization. The present work thoroughly examines the relation between the polarization dependence of SFG signals and the molecular orientation, by comparing SFG measurements and molecular dynamics (MD) simulations of acetonitrile/water solutions. The present SFG experiment and MD simulations yield quite consistent results on the ratios of χ((2)) elements, supporting the reliability of both means. However, the subsequent polarization analysis tends to derive more upright tilt angles of acetonitrile than the direct MD calculations. The reasons for discrepancy are examined in terms of three issues; (i) anisotropy of the Raman tensor, (ii) cross-correlation, and (iii) orientational distribution. The analysis revealed that the issues (i) and (iii) are the main causes of errors in the conventional polarization analysis of SFG spectra. In methyl CH stretching, the anisotropy of Raman tensor cannot be estimated from the simple bond polarizability model. The neglect of the orientational distribution is shown to systematically underestimate the tilt angle of acetonitrile. Further refined use of polarization analysis in collaboration with MD simulations should be proposed.

  7. HackAttack: Game-Theoretic Analysis of Realistic Cyber Conflicts

    SciTech Connect

    Ferragut, Erik M; Brady, Andrew C; Brady, Ethan J; Ferragut, Jacob M; Ferragut, Nathan M; Wildgruber, Max C

    2016-01-01

    Game theory is appropriate for studying cyber conflict because it allows for an intelligent and goal-driven adversary. Applications of game theory have led to a number of results regarding optimal attack and defense strategies. However, the overwhelming majority of applications explore overly simplistic games, often ones in which each participant s actions are visible to every other participant. These simplifications strip away the fundamental properties of real cyber conflicts: probabilistic alerting, hidden actions, unknown opponent capabilities. In this paper, we demonstrate that it is possible to analyze a more realistic game, one in which different resources have different weaknesses, players have different exploits, and moves occur in secrecy, but they can be detected. Certainly, more advanced and complex games are possible, but the game presented here is more realistic than any other game we know of in the scientific literature. While optimal strategies can be found for simpler games using calculus, case-by-case analysis, or, for stochastic games, Q-learning, our more complex game is more naturally analyzed using the same methods used to study other complex games, such as checkers and chess. We define a simple evaluation function and employ multi-step searches to create strategies. We show that such scenarios can be analyzed, and find that in cases of extreme uncertainty, it is often better to ignore one s opponent s possible moves. Furthermore, we show that a simple evaluation function in a complex game can lead to interesting and nuanced strategies.

  8. Theoretical analysis of integral neutron transport equation using collision probability method with quadratic flux approach

    SciTech Connect

    Shafii, Mohammad Ali Meidianti, Rahma Wildian, Fitriyani, Dian; Tongkukut, Seni H. J.; Arkundato, Artoto

    2014-09-30

    Theoretical analysis of integral neutron transport equation using collision probability (CP) method with quadratic flux approach has been carried out. In general, the solution of the neutron transport using the CP method is performed with the flat flux approach. In this research, the CP method is implemented in the cylindrical nuclear fuel cell with the spatial of mesh being conducted into non flat flux approach. It means that the neutron flux at any point in the nuclear fuel cell are considered different each other followed the distribution pattern of quadratic flux. The result is presented here in the form of quadratic flux that is better understanding of the real condition in the cell calculation and as a starting point to be applied in computational calculation.

  9. Procedures for experimental measurement and theoretical analysis of large plastic deformations

    NASA Technical Reports Server (NTRS)

    Morris, R. E.

    1974-01-01

    Theoretical equations are derived and analytical procedures are presented for the interpretation of experimental measurements of large plastic strains in the surface of a plate. Orthogonal gage lengths established on the metal surface are measured before and after deformation. The change in orthogonality after deformation is also measured. Equations yield the principal strains, deviatoric stresses in the absence of surface friction forces, true stresses if the stress normal to the surface is known, and the orientation angle between the deformed gage line and the principal stress-strain axes. Errors in the measurement of nominal strains greater than 3 percent are within engineering accuracy. Applications suggested for this strain measurement system include the large-strain-stress analysis of impact test models, burst tests of spherical or cylindrical pressure vessels, and to augment small-strain instrumentation tests where large strains are anticipated.

  10. Theoretical Analysis of Heat Pump Cycle Characteristics with Pure Refrigerants and Binary Refrigerant Mixtures

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru; Uematsu, Masahiko; Watanabe, Koichi

    In recent years there has been an increasing interest of the use of nonazeotropic binary mixtures to improve performance in heat pump systems, and to restrict the consumption of chlorofluorocarbon (CFC) refrigerants as internationally agreed-upon in the Montreal Protocol. However, the available knowledge on the thermophysical properties of mixtures is very much limited particularly with respect to quantitative information. In order to systematize cycle performance with Refrigerant 12 (CCl2F2) + Refrigerant 22 (CHClF2) and Refrigerant 22 + Refrigerant 114 (CClF2-CClF2) systems which are technically important halogenated refrigerant mixtures, the heat pump cycle analysis in case of using these mixtures was theoretically studied. It became clear that the maximum coefficients of performance with various pure refrigerants and binary refrigerant mixtures were obtained at the reduced condensing temperature being 0.9 when the same temperature difference between condensing and evaporating temperature was chosen.

  11. Systems theoretic analysis of the central dogma of molecular biology: some recent results.

    PubMed

    Gao, Rui; Yu, Juanyi; Zhang, Mingjun; Tarn, Tzyh-Jong; Li, Jr-Shin

    2010-03-01

    This paper extends our early study on a mathematical formulation of the central dogma of molecular biology, and focuses discussions on recent insights obtained by employing advanced systems theoretic analysis. The goal of this paper is to mathematically represent and interpret the genetic information flow at the molecular level, and explore the fundamental principle of molecular biology at the system level. Specifically, group theory was employed to interpret concepts and properties of gene mutation, and predict backbone torsion angle along the peptide chain. Finite state machine theory was extensively applied to interpret key concepts and analyze the processes related to DNA hybridization. Using the proposed model, we have transferred the character-based model in molecular biology to a sophisticated mathematical model for calculation and interpretation.

  12. Theoretical analysis of electronic absorption spectra of vitamin B12 models

    NASA Astrophysics Data System (ADS)

    Andruniow, Tadeusz; Kozlowski, Pawel M.; Zgierski, Marek Z.

    2001-10-01

    Time-dependent density-functional theory (TD-DFT) is applied to analyze the electronic absorption spectra of vitamin B12. To accomplish this two model systems were considered: CN-[CoIII-corrin]-CN (dicyanocobinamide, DCC) and imidazole-[CoIII-corrin]-CN (cyanocobalamin, ImCC). For both models 30 lowest excited states were calculated together with transition dipole moments. When the results of TD-DFT calculations were directly compared with experiment it was found that the theoretical values systematically overestimate experimental data by approximately 0.5 eV. The uniform adjustment of the calculated transition energies allowed detailed analysis of electronic absorption spectra of vitamin B12 models. All absorption bands in spectral range 2.0-5.0 eV were readily assigned. In particular, TD-DFT calculations were able to explain the origin of the shift of the lowest absorption band caused by replacement of the-CN axial ligand by imidazole.

  13. Theoretical analysis of AC electric field transmission into biological tissue through frozen saline for electroporation.

    PubMed

    Xiao, Chunyan; Rubinsky, Boris

    2014-12-01

    An analytical model was used to explore the feasibility of sinusoidal electric field transmission across a frozen saline layer into biological tissue. The study is relevant to electroporation and permeabilization of the cell membrane by electric fields. The concept was analyzed for frequencies in the range of conventional electroporation frequencies and electric field intensity. Theoretical analysis for a variety of tissues show that the transmission of electroporation type electric fields through a layer of frozen saline into tissue is feasible and the behavior of this composite system depends on tissue type, frozen domain temperature, and frequency. Freezing could become a valuable method for adherence of electroporation electrodes to moving tissue surfaces, such as the heart in the treatment of atrial fibrillation or blood vessels for the treatment of restenosis.

  14. Disturbed connectivity of EEG functional networks in alcoholism: a graph-theoretic analysis.

    PubMed

    Cao, Rui; Wu, Zheng; Li, Haifang; Xiang, Jie; Chen, Junjie

    2014-01-01

    Generally, an alcoholic's brain shows explicit damage. However, in cognitive tasks, the correlation between the topological structural changes of the brain networks and the brain damage is still unclear. Scalp electrodes and synchronization likelihood (SL) were applied to the constructions of the EGG functional networks of 28 alcoholics and 28 healthy volunteers. The graph-theoretic analysis showed that in cognitive tasks, compared with the healthy control group, the brain networks of alcoholics had smaller clustering coefficients in β1 bands, shorter characteristic path lengths, increased global efficiency, but similar small-world properties. The abnormal topological structure of the alcoholics may be related to the local-function brain damage and the compensation mechanism adopted to complete tasks. This conclusion provides a new perspective for alcohol-related brain damage.

  15. Theoretical analysis for the specific heat and thermal parameters of solid C60

    NASA Astrophysics Data System (ADS)

    Soto, J. R.; Calles, A.; Castro, J. J.

    1997-08-01

    We present the results of a theoretical analysis for the thermal parameters and phonon contribution to the specific heat in solid C60. The phonon contribution to the specific heat is calculated through the solution of the corresponding dynamical matrix, for different points in the Brillouin zone, and the construccion of the partial and generalized phonon density of states. The force constants are obtained from a first principle calculation, using a SCF Hartree-Fock wave function from the Gaussian 92 program. The thermal parameters reported are the effective temperatures and vibrational amplitudes as a function of temperature. Using this model we present a parametization scheme in order to reproduce the general behaviour of the experimental specific heat for these materials.

  16. [A theoretical analysis of coordination in the field of health care: application to coordinated care systems].

    PubMed

    Sebai, Jihane

    2016-01-01

    Various organizational, functional or structural issues have led to a review of the foundations of the former health care system based on a traditional market segmentation between general practice and hospital medicine, and between health and social sectors and marked by competition between private and public sectors. The current reconfiguration of the health care system has resulted in “new” levers explained by the development of a new organizational reconfiguration of the primary health care model. Coordinated care structures (SSC) have been developed in this context by making coordination the cornerstone of relations between professionals to ensure global, continuous and quality health care. This article highlights the contributions of various theoretical approaches to the understanding of the concept of coordination in the analysis of the current specificity of health care.

  17. Theoretical analysis of tablet hardness prediction using chemoinformetric near-infrared spectroscopy.

    PubMed

    Tanabe, Hideaki; Otsuka, Kuniko; Otsuka, Makoto

    2007-07-01

    In order to clarify the theoretical basis of the variability in the measurement of tablet hardness by compression pressure, NIR spectroscopic methods were used to predict tablet hardness of the formulations. Tablets (200 mg, 8 mm in diameter) consisting of berberine chloride, lactose, and potato starch were formed at various compression pressures (59, 78, 98, 127, 195 MPa). The hardness and the distribution of micropores were measured. The reflectance NIR spectra of various compressed tablets were used as a calibration set to establish a calibration model to predict tablet hardness by principal component regression (PCR) analysis. The distribution of micropores was shifted to a smaller pore size with increasing compression pressure. The total pore volume of tablets decreased as the compression pressure increased. The hardness increased as the compression pressure increased. The hardness could be predicted using a calibration model consisting of 7 principal components (PCs) obtained by PCR. The relationship between the predicted and the actual hardness values exhibited a straight line, an R(2) of 0.925. In order to understand the theoretical analysis (scientific background) of calibration models used to evaluate tablet hardness, the standard error of cross validation (SEV) values, the loading vectors of each PC and the regression vector were investigated. The result obtained with the calibration models for hardness suggested that the regression vector might involve physical and chemical factors. In contrast, the porosity could be predicted using a calibration model composed of 2 PCs. The relationship between the predicted and the actual total pore volume showed a straight line with R(2) = 0.801. The regression vector of the total pore volume might be due to physical factors.

  18. Graph theoretical analysis of resting-state MEG data: Identifying interhemispheric connectivity and the default mode.

    PubMed

    Maldjian, Joseph A; Davenport, Elizabeth M; Whitlow, Christopher T

    2014-08-01

    Interhemispheric connectivity with resting state MEG has been elusive, and demonstration of the default mode network (DMN) yet more challenging. Recent seed-based MEG analyses have shown interhemispheric connectivity using power envelope correlations. The purpose of this study is to compare graph theoretic maps of brain connectivity generated using MEG with and without signal leakage correction to evaluate for the presence of interhemispheric connectivity. Eight minutes of resting state eyes-open MEG data were obtained in 22 normal male subjects enrolled in an IRB-approved study (ages 16-18). Data were processed using an in-house automated MEG processing pipeline and projected into standard (MNI) source space at 7mm resolution using a scalar beamformer. Mean beta-band amplitude was sampled at 2.5second epochs from the source space time series. Leakage correction was performed in the time domain of the source space beam formed signal prior to amplitude transformation. Graph theoretic voxel-wise source space correlation connectivity analysis was performed for leakage corrected and uncorrected data. Degree maps were thresholded across subjects for the top 20% of connected nodes to identify hubs. Additional degree maps for sensory, visual, motor, and temporal regions were generated to identify interhemispheric connectivity using laterality indices. Hubs for the uncorrected MEG networks were predominantly symmetric and midline, bearing some resemblance to fMRI networks. These included the cingulate cortex, bilateral inferior frontal lobes, bilateral hippocampal formations and bilateral cerebellar hemispheres. These uncorrected networks however, demonstrated little to no interhemispheric connectivity using the ROI-based degree maps. Leakage corrected MEG data identified the DMN, with hubs in the posterior cingulate and biparietal areas. These corrected networks demonstrated robust interhemispheric connectivity for the ROI-based degree maps. Graph theoretic analysis of

  19. Theoretical analysis of rotating two phase detonation in a rocket motor

    NASA Technical Reports Server (NTRS)

    Shen, I.; Adamson, T. C., Jr.

    1973-01-01

    Tangential mode, non-linear wave motion in a liquid propellant rocket engine is studied, using a two phase detonation wave as the reaction model. Because the detonation wave is followed immediately by expansion waves, due to the side relief in the axial direction, it is a Chapman-Jouguet wave. The strength of this wave, which may be characterized by the pressure ratio across the wave, as well as the wave speed and the local wave Mach number, are related to design parameters such as the contraction ratio, chamber speed of sound, chamber diameter, propellant injection density and velocity, and the specific heat ratio of the burned gases. In addition, the distribution of flow properties along the injector face can be computed. Numerical calculations show favorable comparison with experimental findings. Finally, the effects of drop size are discussed and a simple criterion is found to set the lower limit of validity of this strong wave analysis.

  20. Theoretical analysis of selectivity mechanisms in molecular transport through channels and nanopores

    SciTech Connect

    Agah, Shaghayegh; Pasquali, Matteo; Kolomeisky, Anatoly B.

    2015-01-28

    Selectivity is one of the most fundamental concepts in natural sciences, and it is also critically important in various technological, industrial, and medical applications. Although there are many experimental methods that allow to separate molecules, frequently they are expensive and not efficient. Recently, a new method of separation of chemical mixtures based on utilization of channels and nanopores has been proposed and successfully tested in several systems. However, mechanisms of selectivity in the molecular transport during the translocation are still not well understood. Here, we develop a simple theoretical approach to explain the origin of selectivity in molecular fluxes through channels. Our method utilizes discrete-state stochastic models that take into account all relevant chemical transitions and can be solved analytically. More specifically, we analyze channels with one and two binding sites employed for separating mixtures of two types of molecules. The effects of the symmetry and the strength of the molecular-pore interactions are examined. It is found that for one-site binding channels, the differences in the strength of interactions for two species drive the separation. At the same time, in more realistic two-site systems, the symmetry of interaction potential becomes also important. The most efficient separation is predicted when the specific binding site is located near the entrance to the nanopore. In addition, the selectivity is higher for large entrance rates into the channel. It is also found that the molecular transport is more selective for repulsive interactions than for attractive interactions. The physical-chemical origin of the observed phenomena is discussed.

  1. Component Analysis of Simple Span vs. Complex Span Adaptive Working Memory Exercises: A Randomized, Controlled Trial

    PubMed Central

    Gibson, Bradley S.; Kronenberger, William G.; Gondoli, Dawn M.; Johnson, Ann C.; Morrissey, Rebecca A.; Steeger, Christine M.

    2012-01-01

    There has been growing interest in using adaptive training interventions such as Cogmed-RM to increase the capacity of working memory (WM), but this intervention may not be optimally designed. For instance, Cogmed-RM can target the primary memory (PM) component of WM capacity, but not the secondary memory (SM) component. The present study hypothesized that Cogmed-RM does not target SM capacity because the simple span exercises it uses may not cause a sufficient amount of information to be lost from PM during training. To investigate, we randomly assigned participants to either a standard (simple span; N = 31) or a modified (complex span; N = 30) training condition. The main findings showed that SM capacity did not improve, even in the modified training condition. Hence, the potency of span-based WM interventions cannot be increased simply by converting simple span exercises into complex span exercises. PMID:23066524

  2. Synthesis, spectroscopic analysis and theoretical study of new pyrrole-isoxazoline derivatives

    NASA Astrophysics Data System (ADS)

    Rawat, Poonam; Singh, R. N.; Baboo, Vikas; Niranjan, Priydarshni; Rani, Himanshu; Saxena, Rajat; Ahmad, Sartaj

    2017-02-01

    In the present work, we have efficiently synthesized the pyrrole-isoxazoline derivatives (4a-d) by cyclization of substituted 4-chalconylpyrrole (3a-d) with hydroxylamine hydrochloride. The reactivity of substituted 4-chalconylpyrrole (3a-d), towards nucleophiles hydroxylamine hydrochloride was evaluated on the basis of electrophilic reactivity descriptors (fk+, sk+, ωk+) and they were found to be high at unsaturated β carbon of chalconylpyrrole indicating its more proneness to nucleophilic attack and thereby favoring the formation of reported new pyrrole-isoxazoline compounds (4a-d). The structures of newly synthesized pyrrole-isoxazoline derivatives were derived from IR, 1H NMR, Mass, UV-Vis and elemental analysis. All experimental spectral data corroborate well with the calculated spectral data. The FT-IR analysis shows red shifts in vN-H and vC = O stretching due to dimer formation through intermolecular hydrogen bonding. On basis set superposition error correction, the intermolecular interaction energy for (4a-d) is found to be 10.10, 9.99, 10.18, 11.01 and 11.19 kcal/mol respectively. The calculated first hyperpolarizability (β0) values of (4a-d) molecules are in the range of 7.40-9.05 × 10-30 esu indicating their suitability for non-linear optical (NLO) applications. Experimental spectral results, theoretical data, analysis of chalcone intermediates and pyrrole-isoxazolines find usefulness in advancement of pyrrole-azole chemistry.

  3. Topological analysis of electron density and the electrostatic properties of isoniazid: an experimental and theoretical study.

    PubMed

    Rajalakshmi, Gnanasekaran; Hathwar, Venkatesha R; Kumaradhas, Poomani

    2014-04-01

    Isoniazid (isonicotinohydrazide) is an important first-line antitubercular drug that targets the InhA enzyme which synthesizes the critical component of the mycobacterial cell wall. An experimental charge-density analysis of isoniazid has been performed to understand its structural and electronic properties in the solid state. A high-resolution single-crystal X-ray intensity data has been collected at 90 K. An aspherical multipole refinement was carried out to explore the topological and electrostatic properties of the isoniazid molecule. The experimental results were compared with the theoretical charge-density calculations performed using CRYSTAL09 with the B3LYP/6-31G** method. A topological analysis of the electron density reveals that the Laplacian of electron density of the N-N bond is significantly less negative, which indicates that the charges at the b.c.p. (bond-critical point) of the bond are least accumulated, and so the bond is considered to be weak. As expected, a strong negative electrostatic potential region is present in the vicinity of the O1, N1 and N3 atoms, which are the reactive locations of the molecule. The C-H···N, C-H···O and N-H···N types of intermolecular hydrogen-bonding interactions stabilize the crystal structure. The topological analysis of the electron density on hydrogen bonding shows the strength of intermolecular interactions.

  4. Control Theoretic Approach to Iterative Methods for Large-scale Toeplitz-type Systems with Application to Magnetic Field Analysis

    NASA Astrophysics Data System (ADS)

    Oda, Tomohito; Kashima, Kenji; Imura, Jun-Ichi; Miyazaki, Shuji; Morita, Hiroshi

    In this paper, stationary iterative methods for large-scale Toeplitz-type systems are investigated from a control theoretic point of view. We utilize spatially invariant structure of Toeplitz matrices, to avoid the curse of dimensionality arising in analysis and design of the convergence properties. Nonlinearities in the system are theoretically handled within the small gain and stability analysis for Lur'e systems. This theory enables us to achieve the desired global convergence of the proposed numerical scheme. We also evaluate the efficacy of the proposed method through an application to magnetic field analysis.

  5. Error Analysis of Present Simple Tense in the Interlanguage of Adult Arab English Language Learners

    ERIC Educational Resources Information Center

    Muftah, Muneera; Rafik-Galea, Shameem

    2013-01-01

    The present study analyses errors on present simple tense among adult Arab English language learners. It focuses on the error on 3sg "-s" (the third person singular present tense agreement morpheme "-s"). The learners are undergraduate adult Arabic speakers learning English as a foreign language. The study gathered data from…

  6. A Simple Empirical Analysis of the Enthalpies of Formation of Lanthanide Halides and Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1986-01-01

    Proposes a simple and general method whereby the lattice energies of lanthanide(II) and (IV) compounds are derived directly from those found experimentally for the corresponding lanthanide(III) compounds. The method is applicable to all lanthanide halides and oxides and involves calculations which can be easily and quickly performed by students.…

  7. Site-city interaction: theoretical, numerical and experimental crossed-analysis

    NASA Astrophysics Data System (ADS)

    Schwan, L.; Boutin, C.; Padrón, L. A.; Dietz, M. S.; Bard, P.-Y.; Taylor, C.

    2016-05-01

    The collective excitation of city structures by a seismic wavefield and the subsequent multiple Structure-Soil-Structure Interactions (SSSIs) between the buildings are usually disregarded in conventional seismology and earthquake engineering practice. The objective here is to qualify and quantify these complex multiple SSSIs through the design of an elementary study case, which serves as a benchmark for theoretical, numerical and experimental crossed-analysis. The experimental specimen consists of an idealized site-city setup with up to 37 anisotropic resonant structures arranged at the top surface of an elastic layer and in co-resonance with it. The experimental data from shaking table measurements is compared with the theoretical and numerical results provided respectively by an equivalent city-impedance model derived analytically from homogenization in the long-wavelength approximation and a model based on boundary elements. The signatures of the site-city interactions are identified in the frequency, time and space domain, and in particular consist of a frequency-dependent free/rigid switch in the surface condition at the city resonance, beatings in the records and the depolarization of the wavefield. A parametric study on the city density shows that multiple SSSIs among the city structures (five are sufficient) can have significant effects on both the seismic response of its implantation site and that of the buildings. Key parameters are provided to assess site-city interactions in the low seismic frequency range: They involve the mass and rigidity of the city compared to those of the soil and the damping of the building.

  8. Theoretical Analysis of the Optical Propagation Characteristics in a Fiber-Optic Surface Plasmon Resonance Sensor

    PubMed Central

    Liu, Linlin; Yang, Jun; Yang, Zhong; Wan, Xiaoping; Hu, Ning; Zheng, Xiaolin

    2013-01-01

    Surface plasmon resonance (SPR) sensor is widely used for its high precision and real-time analysis. Fiber-optic SPR sensor is easy for miniaturization, so it is commonly used in the development of portable detection equipment. It can also be used for remote, real-time, and online detection. In this study, a wavelength modulation fiber-optic SPR sensor is designed, and theoretical analysis of optical propagation in the optical fiber is also done. Compared with existing methods, both the transmission of a skew ray and the influence of the chromatic dispersion are discussed. The resonance wavelength is calculated at two different cases, in which the chromatic dispersion in the fiber core is considered. According to the simulation results, a novel multi-channel fiber-optic SPR sensor is likewise designed to avoid defaults aroused by the complicated computation of the skew ray as well as the chromatic dispersion. Avoiding the impact of skew ray can do much to improve the precision of this kind of sensor. PMID:23748170

  9. Limit analysis and homogenization of porous materials with Mohr-Coulomb matrix. Part I: Theoretical formulation

    NASA Astrophysics Data System (ADS)

    Anoukou, K.; Pastor, F.; Dufrenoy, P.; Kondo, D.

    2016-06-01

    The present two-part study aims at investigating the specific effects of Mohr-Coulomb matrix on the strength of ductile porous materials by using a kinematic limit analysis approach. While in the Part II, static and kinematic bounds are numerically derived and used for validation purpose, the present Part I focuses on the theoretical formulation of a macroscopic strength criterion for porous Mohr-Coulomb materials. To this end, we consider a hollow sphere model with a rigid perfectly plastic Mohr-Coulomb matrix, subjected to axisymmetric uniform strain rate boundary conditions. Taking advantage of an appropriate family of three-parameter trial velocity fields accounting for the specific plastic deformation mechanisms of the Mohr-Coulomb matrix, we then provide a solution of the constrained minimization problem required for the determination of the macroscopic dissipation function. The macroscopic strength criterion is then obtained by means of the Lagrangian method combined with Karush-Kuhn-Tucker conditions. After a careful analysis and discussion of the plastic admissibility condition associated to the Mohr-Coulomb criterion, the above procedure leads to a parametric closed-form expression of the macroscopic strength criterion. The latter explicitly shows a dependence on the three stress invariants. In the special case of a friction angle equal to zero, the established criterion reduced to recently available results for porous Tresca materials. Finally, both effects of matrix friction angle and porosity are briefly illustrated and, for completeness, the macroscopic plastic flow rule and the voids evolution law are fully furnished.

  10. Electrochemical and theoretical analysis of the reactivity of shikonin derivatives: dissociative electron transfer in esterified compounds.

    PubMed

    Armendáriz-Vidales, Georgina; Frontana, Carlos

    2014-09-07

    An electrochemical and theoretical analysis of a series of shikonin derivatives in aprotic media is presented. Results showed that the first electrochemical reduction signal is a reversible monoelectronic transfer, generating a stable semiquinone intermediate; the corresponding E(I)⁰ values were correlated with calculated values of electroaccepting power (ω(+)) and adiabatic electron affinities (A(Ad)), obtained with BH and HLYP/6-311++G(2d,2p) and considering the solvent effect, revealing the influence of intramolecular hydrogen bonding and the substituting group at position C-2 in the experimental reduction potential. For the second reduction step, esterified compounds isobutyryl and isovalerylshikonin presented a coupled chemical reaction following dianion formation. Analysis of the variation of the dimensionless cathodic peak potential values (ξ(p)) as a function of the scan rate (v) functions and complementary experiments in benzonitrile suggested that this process follows a dissociative electron transfer, in which the rate of heterogeneous electron transfer is slow (~0.2 cm s(-1)), and the rate constant of the chemical process is at least 10(5) larger.

  11. Wettability of graphitic-carbon and silicon surfaces: MD modeling and theoretical analysis

    SciTech Connect

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2015-07-28

    The wettability of graphitic carbon and silicon surfaces was numerically and theoretically investigated. A multi-response method has been developed for the analysis of conventional molecular dynamics (MD) simulations of droplets wettability. The contact angle and indicators of the quality of the computations are tracked as a function of the data sets analyzed over time. This method of analysis allows accurate calculations of the contact angle obtained from the MD simulations. Analytical models were also developed for the calculation of the work of adhesion using the mean-field theory, accounting for the interfacial entropy changes. A calibration method is proposed to provide better predictions of the respective contact angles under different solid-liquid interaction potentials. Estimations of the binding energy between a water monomer and graphite match those previously reported. In addition, a breakdown in the relationship between the binding energy and the contact angle was observed. The macroscopic contact angles obtained from the MD simulations were found to match those predicted by the mean-field model for graphite under different wettability conditions, as well as the contact angles of Si(100) and Si(111) surfaces. Finally, an assessment of the effect of the Lennard-Jones cutoff radius was conducted to provide guidelines for future comparisons between numerical simulations and analytical models of wettability.

  12. Theoretical Analysis of Heat Pump Cycle Characteristics with Pure Refrigerants and Binary Refrigerant Mixtures

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru; Uematsu, Masahiko; Watanabe, Koichi

    In recent years there has been an increasing interest of the use of nonazeotropic binary mixtures to improve performance in heat pump systems, and to restrict the consumption of chlorofluorocarbon (CFC) refrigerants as internationally agreed-upon in the Montreal Protocol. However, the available knowledge on the thermophysical properties of mixtures is very much limited particularly with respect to quantitative information. In order to examine cycle performance for Refrigerant 12 (CCl2F2) + Refrigerant 22 (CHClF2) and Refrigerant 22 + Refrigerant 114 (CClF2-CClF2) systems which are technically important halogenated refrigerant mixtures, the heat pump cycle analysis in case of using pure Refrigerants 12, 22 and 114 was theoretically carried out in the present paper. For the purpose of systematizing the heat pump cycle characteristics with pure refrigerants, the cycle analysis for Refrigerants 502, 13B1, 152a, 717 (NH3) and 290 (C3H8) was also examined. It became clear that the maximum coefficients of performance with various refrigerants were obtained at the reduced condensing temperature being 0.9 when the same temperature difference between condensing and evaporating temperature was chosen.

  13. Theoretical analysis of the kinetics of DNA hybridization with gel-immobilized oligonucleotides.

    PubMed Central

    Livshits, M A; Mirzabekov, A D

    1996-01-01

    A new method of DNA sequencing by hybridization using a microchip containing a set of immobilized oligonucleotides is being developed. A theoretical analysis is presented of the kinetics of DNA hybridization with deoxynucleotide molecules chemically tethered in a polyacrylamide gel layer. The analysis has shown that long-term evolution of the spatial distribution and of the amount of DNA bound in a hybridization cell is governed by "retarded diffusion," i.e., diffusion of the DNA interrupted by repeated association and dissociation with immobile oligonucleotide molecules. Retarded diffusion determines the characteristic time of establishing a final equilibrium state in a cell, i.e., the state with the maximum quantity and a uniform distribution of bound DNA. In the case of cells with the most stable, perfect duplexes, the characteristic time of retarded diffusion (which is proportional to the equilibrium binding constant and to the concentration of binding sites) can be longer than the duration of the real hybridization procedure. This conclusion is indirectly confirmed by the observation of nonuniform fluorescence of labeled DNA in perfect-match hybridization cells (brighter at the edges). For optimal discrimination of perfect duplexes from duplexes with mismatches the hybridization process should be brought to equilibrium under low-temperature nonsaturation conditions for all cells. The kinetic differences between perfect and nonperfect duplexes in the gel allow further improvement in the discrimination through additional washing at low temperature after hybridization. Images FIGURE 1 PMID:8913616

  14. Accounting for the kinetics in order parameter analysis: Lessons from theoretical models and a disordered peptide

    NASA Astrophysics Data System (ADS)

    Berezovska, Ganna; Prada-Gracia, Diego; Mostarda, Stefano; Rao, Francesco

    2012-11-01

    Molecular simulations as well as single molecule experiments have been widely analyzed in terms of order parameters, the latter representing candidate probes for the relevant degrees of freedom. Notwithstanding this approach is very intuitive, mounting evidence showed that such descriptions are inaccurate, leading to ambiguous definitions of states and wrong kinetics. To overcome these limitations a framework making use of order parameter fluctuations in conjunction with complex network analysis is investigated. Derived from recent advances in the analysis of single molecule time traces, this approach takes into account the fluctuations around each time point to distinguish between states that have similar values of the order parameter but different dynamics. Snapshots with similar fluctuations are used as nodes of a transition network, the clusterization of which into states provides accurate Markov-state-models of the system under study. Application of the methodology to theoretical models with a noisy order parameter as well as the dynamics of a disordered peptide illustrates the possibility to build accurate descriptions of molecular processes on the sole basis of order parameter time series without using any supplementary information.

  15. Theoretical analysis of electromigration-induced failure of metallic thin films due to transgranular void propagation

    SciTech Connect

    Gungor, M.R.; Maroudas, D.

    1999-02-01

    Failure of metallic thin films driven by electromigration is among the most challenging materials reliability problems in microelectronics toward ultra-large-scale integration. One of the most serious failure mechanisms in thin films with bamboo grain structure is the propagation of transgranular voids, which may lead to open-circuit failure. In this article, a comprehensive theoretical analysis is presented of the complex nonlinear dynamics of transgranular voids in metallic thin films as determined by capillarity-driven surface diffusion coupled with drift induced by electromigration. Our analysis is based on self-consistent dynamical simulations of void morphological evolution and it is aided by the conclusions of an approximate linear stability theory. Our simulations emphasize that the strong dependence of surface diffusivity on void surface orientation, the strength of the applied electric field, and the void size play important roles in the dynamics of the voids. The simulations predict void faceting, formation of wedge-shaped voids due to facet selection, propagation of slit-like features emanating from void surfaces, open-circuit failure due to slit propagation, as well as appearance and disappearance of soliton-like features on void surfaces prior to failure. These predictions are in very good agreement with recent experimental observations during accelerated electromigration testing of unpassivated metallic films. The simulation results are used to establish conditions for the formation of various void morphological features and discuss their serious implications for interconnect reliability. {copyright} {ital 1999 American Institute of Physics.}

  16. Theoretical analysis of saturation and limit cycles in short pulse FEL oscillators

    SciTech Connect

    Piovella, N.; Chaix, P.; Jaroszynski, D.

    1995-12-31

    We derive a model for the non linear evolution of a short pulse oscillator from low signal up to saturation in the small gain regime. This system is controlled by only two independent parameters: cavity detuning and losses. Using a closure relation, this model reduces to a closed set of 5 non linear partial differential equations for the EM field and moments of the electron distribution. An analysis of the linearised system allows to define and calculate the eigenmodes characterising the small signal regime. An arbitrary solution of the complete nonlinear system can then be expanded in terms of these eigenmodes. This allows interpreting various observed nonlinear behaviours, including steady state saturation, limit cycles, and transition to chaos. The single mode approximation reduces to a Landau-Ginzburg equation. It allows to obtain gain, nonlinear frequency shift, and efficiency as functions of cavity detuning and cavity losses. A generalisation to two modes allows to obtain a simple description of the limit cycle behaviour, as a competition between these two modes. An analysis of the transitions to more complex dynamics is also given. Finally, the analytical results are compared to the experimental data from the FELIX experiment.

  17. Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials.

    PubMed

    Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

    2015-01-01

    Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound

  18. Morphologic Analysis of Lunar Craters in the Simple-to-Complex Transition

    NASA Astrophysics Data System (ADS)

    Chandnani, M.; Herrick, R. R.; Kramer, G. Y.

    2015-12-01

    The diameter range of 15 km to 20 km on the Moon is within the transition from simple to complex impact craters. We examined 207 well preserved craters in this diameter range distributed across the moon using high resolution Lunar Reconnaissance Orbiter Camera Wide Angle Camera Mosaic (WAC) and Narrow Angle Camera (NAC) data. A map of the distribution of the 207 craters on the Moon using the global LROC WAC mosaic has been attahced with the abstract. By examining craters of similar diameter, impact energy is nearly constant, so differences in shape and morphology must be due to either target (e.g., porosity, density, coherence, layering) or impactor (e.g., velocity, density) properties. On the basis of the crater morphology, topographic profiles and depth-diameter ratio, the craters were classified into simple, craters with slumped walls, craters with both slumping and terracing, those containing a central uplift only, those with a central uplift and slumping, and the craters with a central uplift accompanied by both slumping and terracing, as shown in the image. It was observed that simple craters and craters with slumped walls occur predominately on the lunar highlands. The majority of the craters with terraced walls and all classes of central uplifts were observed predominately on the mare. In short, in this size range craters in the highlands were generally simple craters with occasionally some slumped material in the center, and the more developed features (terracing, central peak) were associated with mare craters. This is somewhat counterintuitive, as we expect the highlands to be generally weaker and less consolidated than the mare. We hypothesize that the presence of rheologic layering in the mare may be the cause of the more complex features that we observe. Relatively weak layers in the mare could develop through regolith formation between individual flows, or perhaps by variations within or between the flows themselves.

  19. Experimental and Theoretical Analysis of Central H{sub {beta}} Asymmetry

    SciTech Connect

    Demura, A. V.; Demchenko, G. V.; Djurovic, S.; Cirisan, M.; Nikolic, D.; Gigosos, M. A.; Gonzalez, M. A.

    2008-10-22

    The hydrogen Balmer beta line is used as a plasma diagnostics tool for a long time. It is well known that the experimental profiles of H{sub {beta}} line exhibit an asymmetry while some of most commonly used theoretical models, due to the employed approximations, give unshifted and symmetrical profiles. In the present work the central part of H{sub {beta}} profile is reanalyzed experimentally and in terms of two theoretical approaches based correspondingly on the Standard Theory (ST) assumptions and on the electric field computer simulation method. The present experimental and theoretical results are compared with the obtained earlier experimental and theoretical data.

  20. Theoretical Analysis of the Relative Impact of Obesity on Hemodynamic Stability During Acute Hemorrhagic Shock

    PubMed Central

    Sterling, Sarah A.; Jones, Alan E.; Coleman, Thomas G.; Summers, Richard L.

    2015-01-01

    Background: Evidence suggests that morbid obesity may be an independent risk factor for adverse outcomes in patients with traumatic injuries. Objectives: In this study, a theoretic analysis using a derivation of the Guyton model of cardiovascular physiology examines the expected impact of obesity on hemodynamic changes in Mean Arterial Pressure (MAP) and Cardiac Output (CO) during Hemorrhagic Shock (HS). Patients and Methods: Computer simulation studies were used to predict the relative impact of increasing Body Mass Index (BMI) on global hemodynamic parameters during HS. The analytic procedure involved recreating physiologic conditions associated with changing BMI for a virtual subject in an In Silico environment. The model was validated for the known effect of a BMI of 30 on iliofemoral venous pressures. Then, the relative effect of changing BMI on the outcome of target cardiovascular parameters was examined during simulated acute loss of blood volume in class II hemorrhage. The percent changes in these parameters were compared between the virtual nonobese and obese subjects. Model parameter values are derived from known population distributions, producing simulation outputs that can be used in a deductive systems analysis assessment rather than traditional frequentist statistical methodologies. Results: In hemorrhage simulation, moderate increases in BMI were found to produce greater decreases in MAP and CO compared to the normal subject. During HS, the virtual obese subject had 42% and 44% greater falls in CO and MAP, respectively, compared to the nonobese subject. Systems analysis of the model revealed that an increase in resistance to venous return due to changes in intra-abdominal pressure resulting from obesity was the critical mechanism responsible for the differences. Conclusions: This study suggests that obese patients in HS may have a higher risk of hemodynamic instability compared to their nonobese counterparts primarily due to obesity

  1. Language in the brain at rest: new insights from resting state data and graph theoretical analysis

    PubMed Central

    Muller, Angela M.; Meyer, Martin

    2014-01-01

    In humans, the most obvious functional lateralization is the specialization of the left hemisphere for language. Therefore, the involvement of the right hemisphere in language is one of the most remarkable findings during the last two decades of fMRI research. However, the importance of this finding continues to be underestimated. We examined the interaction between the two hemispheres and also the role of the right hemisphere in language. From two seeds representing Broca's area, we conducted a seed correlation analysis (SCA) of resting state fMRI data and could identify a resting state network (RSN) overlapping to significant extent with a language network that was generated by an automated meta-analysis tool. To elucidate the relationship between the clusters of this RSN, we then performed graph theoretical analyses (GTA) using the same resting state dataset. We show that the right hemisphere is clearly involved in language. A modularity analysis revealed that the interaction between the two hemispheres is mediated by three partitions: A bilateral frontal partition consists of nodes representing the classical left sided language regions as well as two right-sided homologs. The second bilateral partition consists of nodes from the right frontal, the left inferior parietal cortex as well as of two nodes within the posterior cerebellum. The third partition is also bilateral and comprises five regions from the posterior midline parts of the brain to the temporal and frontal cortex, two of the nodes are prominent default mode nodes. The involvement of this last partition in a language relevant function is a novel finding. PMID:24808843

  2. Language in the brain at rest: new insights from resting state data and graph theoretical analysis.

    PubMed

    Muller, Angela M; Meyer, Martin

    2014-01-01

    In humans, the most obvious functional lateralization is the specialization of the left hemisphere for language. Therefore, the involvement of the right hemisphere in language is one of the most remarkable findings during the last two decades of fMRI research. However, the importance of this finding continues to be underestimated. We examined the interaction between the two hemispheres and also the role of the right hemisphere in language. From two seeds representing Broca's area, we conducted a seed correlation analysis (SCA) of resting state fMRI data and could identify a resting state network (RSN) overlapping to significant extent with a language network that was generated by an automated meta-analysis tool. To elucidate the relationship between the clusters of this RSN, we then performed graph theoretical analyses (GTA) using the same resting state dataset. We show that the right hemisphere is clearly involved in language. A modularity analysis revealed that the interaction between the two hemispheres is mediated by three partitions: A bilateral frontal partition consists of nodes representing the classical left sided language regions as well as two right-sided homologs. The second bilateral partition consists of nodes from the right frontal, the left inferior parietal cortex as well as of two nodes within the posterior cerebellum. The third partition is also bilateral and comprises five regions from the posterior midline parts of the brain to the temporal and frontal cortex, two of the nodes are prominent default mode nodes. The involvement of this last partition in a language relevant function is a novel finding.

  3. Field theoretic analysis of a class of planar microwave and optoelectronic structures

    NASA Astrophysics Data System (ADS)

    Hahm, Yeon-Chang

    2000-11-01

    With increasing operating frequencies in CMOS RF/microwave integrated circuits, the performance of on- chip interconnects is becoming significantly affected by the lossy substrate. It is the purpose of the first part of this thesis to develop a rigorous field theoretic analysis approach for efficient characterization of single and multiple coupled interconnects on silicon substrate, which is applicable over a wide range of substrate resistivities. The frequency-dependent transmission line parameters of a microstrip on silicon are determined by a new formulation based on a quasi- electrostatic and quasi-magnetostatic spectral domain approach. It is demonstrated that this new quasi-static formulation provides the complete frequency-dependent interconnect characteristics for all three major transmission line modes of operation. In particular, it is shown that in the case of heavily doped CMOS substrates, the distributed series inductance and series resistance parameters are significantly affected by the presence of longitudinal substrate currents giving rise to the substrate skin-effect. The method is further extended to multiple coupled single and multi-level interconnect structures with ground plane and multiple coupled co-planar stripline structures without ground plane. The finite conductor thickness is taken into account in terms of a stacked conductor model. The new quasi-static approach is validated by comparison with results obtained with a full-wave spectral domain method and the commercial planar full-wave electromagnetic field solver HP/Momentum®, as well as published simulation and measurement data. In the second part of this thesis, coupled planar optical interconnect structures are investigated based on a rigorous field theoretic analysis combined with an application of the normal mode theory for coupled transmission lines. A new transfer matrix description for a general optical directional coupler is presented. Based on this transfer matrix formulation

  4. An effectiveness analysis of healthcare systems using a systems theoretic approach

    PubMed Central

    Chuang, Sheuwen; Inder, Kerry

    2009-01-01

    Background The use of accreditation and quality measurement and reporting to improve healthcare quality and patient safety has been widespread across many countries. A review of the literature reveals no association between the accreditation system and the quality measurement and reporting systems, even when hospital compliance with these systems is satisfactory. Improvement of health care outcomes needs to be based on an appreciation of the whole system that contributes to those outcomes. The research literature currently lacks an appropriate analysis and is fragmented among activities. This paper aims to propose an integrated research model of these two systems and to demonstrate the usefulness of the resulting model for strategic research planning. Methods/design To achieve these aims, a systematic integration of the healthcare accreditation and quality measurement/reporting systems is structured hierarchically. A holistic systems relationship model of the administration segment is developed to act as an investigation framework. A literature-based empirical study is used to validate the proposed relationships derived from the model. Australian experiences are used as evidence for the system effectiveness analysis and design base for an adaptive-control study proposal to show the usefulness of the system model for guiding strategic research. Results Three basic relationships were revealed and validated from the research literature. The systemic weaknesses of the accreditation system and quality measurement/reporting system from a system flow perspective were examined. The approach provides a system thinking structure to assist the design of quality improvement strategies. The proposed model discovers a fourth implicit relationship, a feedback between quality performance reporting components and choice of accreditation components that is likely to play an important role in health care outcomes. An example involving accreditation surveyors is developed that

  5. Magnetotelluric observations over the Rhine Graben, France: a simple impedance tensor analysis helps constrain the dominant electrical features

    NASA Astrophysics Data System (ADS)

    Mareschal, M.; Jouanne, V.; Menvielle, M.; Chouteau, M.; Grandis, H.; Tarits, P.

    1992-12-01

    A simple impedance tensor analysis of four magnetotelluric soundings recorded over the ECORS section of the Rhine Graben shows that for periods shorter than about 30 s, induction dominates over channelling. For longer periods, 2-D induction galvanically distorted by surface heterogeneities and/or current chanelled in the Graben can explain the observations; the role of chanelling becomes dominant at periods of the order of a few hundred seconds. In the area considered, induction appears to be controlled by inclusions of saline water in a porous limestone layer (Grande Oolithe) and not by the limits of the Graben with its crystalline shoulder (Vosges). The simple analysis is supported by tipper analyses and by the results of schematic 2-D modelling.

  6. A MoS2 Nanosheet-Based Fluorescence Biosensor for Simple and Quantitative Analysis of DNA Methylation

    PubMed Central

    Xiao, Le; Xu, Li; Gao, Chuan; Zhang, Yulin; Yao, Qunfeng; Zhang, Guo-Jun

    2016-01-01

    MoS2 nanomaterial has unique properties, including innate affinity with ss-DNA and quenching ability for fluorescence dyes. Here, we present the development of a simple fluorescence biosensor based on water-soluble MoS2 nanosheets and restriction endonuclease BstUI for methylation analysis of p16 promoter. The biosensing platform exhibited excellent sensitivity in detecting DNA with a linear range of 100 pM~20 nM and a detection limit of 140 pM. More importantly, our method could distinguish as low as 1% difference in methylation level. Compared with previous methylation analysis, our design is both time saving and simple to operate, avoiding the limitations of PCR-based assays without compromising performance. PMID:27669248

  7. Theoretical analysis for scaling law of thermal blooming based on optical phase deference

    NASA Astrophysics Data System (ADS)

    Sun, Yunqiang; Huang, Zhilong; Ren, Zebin; Chen, Zhiqiang; Guo, Longde; Xi, Fengjie

    2016-10-01

    In order to explore the laser propagation influence of thermal blooming effect of pipe flow and to analysis the influencing factors, scaling law theoretical analysis of the thermal blooming effects in pipe flow are carry out in detail based on the optical path difference caused by thermal blooming effects in pipe flow. Firstly, by solving the energy coupling equation of laser beam propagation, the temperature of the flow is obtained, and then the optical path difference caused by the thermal blooming is deduced. Through the analysis of the influence of pipe size, flow field and laser parameters on the optical path difference, energy scaling parameters Ne=nTαLPR2/(ρɛCpπR02) and geometric scaling parameters Nc=νR2/(ɛL) of thermal blooming for the pipe flow are derived. Secondly, for the direct solution method, the energy coupled equations have analytic solutions only for the straight tube with Gauss beam. Considering the limitation of directly solving the coupled equations, the dimensionless analysis method is adopted, the analysis is also based on the change of optical path difference, same scaling parameters for the pipe flow thermal blooming are derived, which makes energy scaling parameters Ne and geometric scaling parameters Nc have good universality. The research results indicate that when the laser power and the laser beam diameter are changed, thermal blooming effects of the pipeline axial flow caused by optical path difference will not change, as long as you keep energy scaling parameters constant. When diameter or length of the pipe changes, just keep the geometric scaling parameters constant, the pipeline axial flow gas thermal blooming effects caused by optical path difference distribution will not change. That is to say, when the pipe size and laser parameters change, if keeping two scaling parameters with constant, the pipeline axial flow thermal blooming effects caused by the optical path difference will not change. Therefore, the energy scaling

  8. Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

    NASA Technical Reports Server (NTRS)

    Henderson, R. A.; Schrag, R. L.

    1986-01-01

    A summary of modeling the electrical system aspects of a coil and metal target configuration resembling a practical electro-impulse deicing (EIDI) installation, and a simple circuit for providing energy to the coil, was presented. The model was developed in sufficient theoretical detail to allow the generation of computer algorithms for the current in the coil, the magnetic induction on both surfaces of the target, the force between the coil and target, and the impulse delivered to the target. These algorithms were applied to a specific prototype EIDI test system for which the current, magnetic fields near the target surfaces, and impulse were previously measured.

  9. A Model of Resource Allocation in Public School Districts: A Theoretical and Empirical Analysis.

    ERIC Educational Resources Information Center

    Chambers, Jay G.

    This paper formulates a comprehensive model of resource allocation in a local public school district. The theoretical framework specified could be applied equally well to any number of local public social service agencies. Section 1 develops the theoretical model describing the process of resource allocation. This involves the determination of the…

  10. Picture-word interference is a Stroop effect: A theoretical analysis and new empirical findings.

    PubMed

    Starreveld, Peter A; La Heij, Wido

    2016-10-06

    The picture-word interference (PWI) paradigm and the Stroop color-word interference task are often assumed to reflect the same underlying processes. On the basis of a PRP study, Dell'Acqua et al. (Psychonomic Bulletin & Review, 14: 717-722, 2007) argued that this assumption is incorrect. In this article, we first discuss the definitions of Stroop- and picture-word interference. Next, we argue that both effects consist of at least four components that correspond to four characteristics of the distractor word: (1) response-set membership, (2) task relevance, (3) semantic relatedness, and (4) lexicality. On the basis of this theoretical analysis, we conclude that the typical Stroop effect and the typical PWI effect mainly differ in the relative contributions of these four components. Finally, the results of an interference task are reported in which only the nature of the target - color or picture - was manipulated and all other distractor task characteristics were kept constant. The results showed no difference between color and picture targets with respect to all behavioral measures examined. We conclude that the assumption that the same processes underlie verbal interference in color and picture naming is warranted.

  11. Identification of Conserved Moieties in Metabolic Networks by Graph Theoretical Analysis of Atom Transition Networks

    PubMed Central

    Haraldsdóttir, Hulda S.; Fleming, Ronan M. T.

    2016-01-01

    Conserved moieties are groups of atoms that remain intact in all reactions of a metabolic network. Identification of conserved moieties gives insight into the structure and function of metabolic networks and facilitates metabolic modelling. All moiety conservation relations can be represented as nonnegative integer vectors in the left null space of the stoichiometric matrix corresponding to a biochemical network. Algorithms exist to compute such vectors based only on reaction stoichiometry but their computational complexity has limited their application to relatively small metabolic networks. Moreover, the vectors returned by existing algorithms do not, in general, represent conservation of a specific moiety with a defined atomic structure. Here, we show that identification of conserved moieties requires data on reaction atom mappings in addition to stoichiometry. We present a novel method to identify conserved moieties in metabolic networks by graph theoretical analysis of their underlying atom transition networks. Our method returns the exact group of atoms belonging to each conserved moiety as well as the corresponding vector in the left null space of the stoichiometric matrix. It can be implemented as a pipeline of polynomial time algorithms. Our implementation completes in under five minutes on a metabolic network with more than 4,000 mass balanced reactions. The scalability of the method enables extension of existing applications for moiety conservation relations to genome-scale metabolic networks. We also give examples of new applications made possible by elucidating the atomic structure of conserved moieties. PMID:27870845

  12. Intrinsic functional brain architecture derived from graph theoretical analysis in the human fetus.

    PubMed

    Thomason, Moriah E; Brown, Jesse A; Dassanayake, Maya T; Shastri, Rupal; Marusak, Hilary A; Hernandez-Andrade, Edgar; Yeo, Lami; Mody, Swati; Berman, Susan; Hassan, Sonia S; Romero, Roberto

    2014-01-01

    The human brain undergoes dramatic maturational changes during late stages of fetal and early postnatal life. The importance of this period to the establishment of healthy neural connectivity is apparent in the high incidence of neural injury in preterm infants, in whom untimely exposure to ex-uterine factors interrupts neural connectivity. Though the relevance of this period to human neuroscience is apparent, little is known about functional neural networks in human fetal life. Here, we apply graph theoretical analysis to examine human fetal brain connectivity. Utilizing resting state functional magnetic resonance imaging (fMRI) data from 33 healthy human fetuses, 19 to 39 weeks gestational age (GA), our analyses reveal that the human fetal brain has modular organization and modules overlap functional systems observed postnatally. Age-related differences between younger (GA <31 weeks) and older (GA≥31 weeks) fetuses demonstrate that brain modularity decreases, and connectivity of the posterior cingulate to other brain networks becomes more negative, with advancing GA. By mimicking functional principles observed postnatally, these results support early emerging capacity for information processing in the human fetal brain. Current technical limitations, as well as the potential for fetal fMRI to one day produce major discoveries about fetal origins or antecedents of neural injury or disease are discussed.

  13. [Theoretical analysis of the single optical path spectrum detection in biological tissue].

    PubMed

    Chen, Yun; Du, Zhen-hui; Chen, Feng; Xu, Ke-xin

    2008-06-01

    The technology of spectrum detection with high sensitivity is of significance in clinic diagnosis and tissue optical parameter measurement. A new method of difference-modulated laser spectrum detection was developed in the present paper. The measuring light and the reference light are separated from the lasing light source in this method. After passing through the tissue, the measuring light interferes with the reference light, and the frequency character of spectrum includes the information of the difference of optical path-length between the measuring light and reference light. By using the phase sensitive detector, the spectrum signal with different frequency can be separated, and consequently the measuring light passed through the tissue with different optical length will be apart. The mechanism of difference-modulated laser spectrum was analyzed and the value of dominant frequency of spectrum was deduced. Based on the theory of the optical path distribution in biological tissue, the spectrum signature of measuring light was discussed also. The distribution of dominant frequency component is decided by the difference of optical path-length between measuring light and reference light when the modulation parameters are invariable, and the magnitude of tissue' s modulus decay will effect the energy distribution of spectrum frequencies component. Theoretical analysis showed that the method of difference modulation can be used to separate lights according to the optical path-length and realize the single optical path measurement in biological tissue.

  14. A Detection-Theoretic Analysis of Auditory Streaming and Its Relation to Auditory Masking

    PubMed Central

    Chang, An-Chieh; Lee, Jungmee; Heo, Inseok

    2016-01-01

    Research on hearing has long been challenged with understanding our exceptional ability to hear out individual sounds in a mixture (the so-called cocktail party problem). Two general approaches to the problem have been taken using sequences of tones as stimuli. The first has focused on our tendency to hear sequences, sufficiently separated in frequency, split into separate cohesive streams (auditory streaming). The second has focused on our ability to detect a change in one sequence, ignoring all others (auditory masking). The two phenomena are clearly related, but that relation has never been evaluated analytically. This article offers a detection-theoretic analysis of the relation between multitone streaming and masking that underscores the expected similarities and differences between these phenomena and the predicted outcome of experiments in each case. The key to establishing this relation is the function linking performance to the information divergence of the tone sequences, DKL (a measure of the statistical separation of their parameters). A strong prediction is that streaming and masking of tones will be a common function of DKL provided that the statistical properties of sequences are symmetric. Results of experiments are reported supporting this prediction. PMID:27641681

  15. Theoretical analysis of the influence of flexoelectric effect on the defect site in nematic inversion walls

    NASA Astrophysics Data System (ADS)

    Gui-Li, Zheng; Hui, Zhang; Wen-Jiang, Ye; Zhi-Dong, Zhang; Hong-Wei, Song; Li, Xuan

    2016-03-01

    Based on the experimental phenomena of flexoelectric response at defect sites in nematic inversion walls conducted by Kumar et al., we gave the theoretical analysis using the Frank elastic theory. When a direct-current electric field normal to the plane of the substrate is applied to the parallel aligned nematic liquid crystal cell with weak anchoring, the rotation of ±1 defects in the narrow inversion walls can be exhibited. The free energy of liquid crystal molecules around the +1 and -1 defect sites in the nematic inversion walls under the electric field was formulated and the electric-field-driven structural changes at the defect site characterized by polar and azimuthal angles of the local director were simulated. The results reveal that the deviation of azimuthal angle induced by flexoelectric effect are consistent with the switching of extinction brushes at the +1 and -1 defects obtained in the experiment conducted by Kumar et al. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374087, 11274088, and 11304074), the Natural Science Foundation of Hebei Province, China (Grant Nos. A2014202123 and A2016202282), the Research Project of Hebei Education Department, China (Grant Nos. QN2014130 and QN2015260), and the Key Subject Construction Project of Hebei Province University, China.

  16. Game Theoretical Analysis on Cooperation Stability and Incentive Effectiveness in Community Networks.

    PubMed

    Song, Kaida; Wang, Rui; Liu, Yi; Qian, Depei; Zhang, Han; Cai, Jihong

    2015-01-01

    Community networks, the distinguishing feature of which is membership admittance, appear on P2P networks, social networks, and conventional Web networks. Joining the network costs money, time or network bandwidth, but the individuals get access to special resources owned by the community in return. The prosperity and stability of the community are determined by both the policy of admittance and the attraction of the privileges gained by joining. However, some misbehaving users can get the dedicated resources with some illicit and low-cost approaches, which introduce instability into the community, a phenomenon that will destroy the membership policy. In this paper, we analyze on the stability using game theory on such a phenomenon. We propose a game-theoretical model of stability analysis in community networks and provide conditions for a stable community. We then extend the model to analyze the effectiveness of different incentive policies, which could be used when the community cannot maintain its members in certain situations. Then we verify those models through a simulation. Finally, we discuss several ways to promote community network's stability by adjusting the network's properties and give some proposal on the designs of these types of networks from the points of game theory and stability.

  17. Theoretical analysis of interferometer wave front tilt and fringe radiant flux on a rectangular photodetector.

    PubMed

    Smith, Robert; Fuss, Franz Konstantin

    2013-09-06

    This paper is a theoretical analysis of mirror tilt in a Michelson interferometer and its effect on the radiant flux over the active area of a rectangular photodetector or image sensor pixel. It is relevant to sensor applications using homodyne interferometry where these opto-electronic devices are employed for partial fringe counting. Formulas are derived for radiant flux across the detector for variable location within the fringe pattern and with varying wave front angle. The results indicate that the flux is a damped sine function of the wave front angle, with a decay constant of the ratio of wavelength to detector width. The modulation amplitude of the dynamic fringe pattern reduces to zero at wave front angles that are an integer multiple of this ratio and the results show that the polarity of the radiant flux changes exclusively at these multiples. Varying tilt angle causes radiant flux oscillations under an envelope curve, the frequency of which is dependent on the location of the detector with the fringe pattern. It is also shown that a fringe count of zero can be obtained for specific photodetector locations and wave front angles where the combined effect of fringe contraction and fringe tilt can have equal and opposite effects. Fringe tilt as a result of a wave front angle of 0.05° can introduce a phase measurement difference of 16° between a photodetector/pixel located 20 mm and one located 100 mm from the optical origin.

  18. Game Theoretical Analysis on Cooperation Stability and Incentive Effectiveness in Community Networks

    PubMed Central

    Liu, Yi; Qian, Depei; Zhang, Han; Cai, Jihong

    2015-01-01

    Community networks, the distinguishing feature of which is membership admittance, appear on P2P networks, social networks, and conventional Web networks. Joining the network costs money, time or network bandwidth, but the individuals get access to special resources owned by the community in return. The prosperity and stability of the community are determined by both the policy of admittance and the attraction of the privileges gained by joining. However, some misbehaving users can get the dedicated resources with some illicit and low-cost approaches, which introduce instability into the community, a phenomenon that will destroy the membership policy. In this paper, we analyze on the stability using game theory on such a phenomenon. We propose a game-theoretical model of stability analysis in community networks and provide conditions for a stable community. We then extend the model to analyze the effectiveness of different incentive policies, which could be used when the community cannot maintain its members in certain situations. Then we verify those models through a simulation. Finally, we discuss several ways to promote community network’s stability by adjusting the network’s properties and give some proposal on the designs of these types of networks from the points of game theory and stability. PMID:26551649

  19. A theoretical analysis in the time-domain of wave reflection on a bone plate

    NASA Astrophysics Data System (ADS)

    Grimal, Quentin; Naïli, Salah

    2006-11-01

    This paper presents an original method for simulating ultrasonic wave reflection on a fluid-loaded plate. Geometrical and material parameters used are relevant to the "axial transmission technique" (ATT) setup. Devices based on the ATT are used for the assessment of cortical bone strength (estimate of a fracture risk). In this work, the cortical bone layer is represented as a plate of infinite extent surrounded by fluid (soft tissues). A line source and a receiver are placed in the fluid. Transient waves generated upon reflection at the plate-fluid interfaces are addressed. Analytic Green's functions are derived with the generalized ray/Cagniard-de Hoop method. The acoustic response is obtained upon convolution of Green's functions with a given source pulse. The method associates each wave amplitude in the time-domain (lateral waves, reflected body waves, etc.) to a specific term of the final solution. The method is ideally suited to a detailed analysis of the ultrasonic signal for various geometrical and mechanical parameters. The results presented highlight the potential of the method for the understanding of wave phenomena involved in the ATT and similar setups. They also bring new elements that reinforce our theoretical knowledge of the ATT.

  20. Experimental verification of theoretical analysis of Pd/porous-GaAs as a hydrogen sensor

    NASA Astrophysics Data System (ADS)

    Nikfarjam, Alireza; Jamshidi Kalantari, Dara

    2008-10-01

    The Pd/porous GaAs Schottky sensor reveals high potential for hydrogen detection at room temperature (Salehi et al 2006 Sensors Actuators B 113 419-27). The Pd/porous GaAs Schottky sensor fabricated in this study exhibited a considerable increase in sensitivity three times that of the non-porous sensor submitted to 500 ppm hydrogen gas at room temperature. The theoretical analysis presented here proves that the sensitivity of the porous sample should be more than that in the non-porous sample and this higher sensitivity refers to more hydrogen adsorption at the interface of the contact. The increased sensitivity coefficient in the porous sensor is related to the morphology of the surface and is a function of two parameters: increase in surface area and density of cavities between pore walls (number of pores which is important in catalyzers). We believe that porosity, in addition to increased surface area and adsorption site, causes an additional increase in sensitivity. Moreover, the response time of the sensors was modelled for non-porous and porous samples exposed to hydrogen gas. As analytical predictions were experimentally verified, the porous sample exhibited a rise time comparable to the non-porous sample but in spite of a low rise time the recovery time of the porous sample is much larger (about four times) than that of the non-porous sample.

  1. A novel self-powered MR damper: theoretical and experimental analysis

    NASA Astrophysics Data System (ADS)

    Xinchun, Guan; Yonghu, Huang; Yi, Ru; Hui, Li; Jinping, Ou

    2015-10-01

    This paper presents a novel magnetorheological (MR) damper with a self-powered capability, which is proposed to have energy harvesting and MR damping technologies integrated into a single device. Vibration energy harvesting mechanisms were adopted, based on ball-screw mechanisms and a rotary permanent magnet dc generator, to convert the external vibration energy into electrical energy to power the MR damping unit. The configuration and operating principles of the proposed self-powered MR damper were presented. Considering the core loss effect on the magnetic field, a theoretical analysis of the proposed MR damper was carried out and a mechanical model was developed. Finally, a prototype with a capacity of 10 kN was fabricated and experimentally investigated in both the direct-supply mode and the supply-with-rectifier mode. The results indicated that the proposed configuration is feasible and that both modes can realize good self-adaptability of the MR damping force. However, the direct-supply mode has a sag effect in the force-displacement curve and provides a lower energy-dissipating capacity than the direct-supply mode does under the same conditions.

  2. Spectroscopic and vibrational analysis of the methoxypsoralen system: A comparative experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Yuan, H.; Vo-Dinh, T.

    2013-03-01

    Raman spectra measurements and density functional theory (DFT) calculations were performed to investigate three psoralens: 5-amino-8-methoxypsoralen (5-A-8-MOP), 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) with the aim of differentiating these similar bioactive molecules. The Raman spectra were recorded in the region 300-3500 cm-1. All three psoralens were found to have similar Raman spectrum in the region 1500-1650 cm-1. 5-A-8-MOP can be easily differentiated from 5-MOP or 8-MOP based on the Raman spectrum. The Raman spectrum differences at 651 and 795 cm-1 can be used to identify 5-MOP from 8-MOP. The theoretically computed vibrational frequencies and relative peak intensities were compared with experimental data. DFT calculations using the B3LYP method and 6-311++G(d,p) basis set were found to yield results that are very comparable to experimental Raman spectra. Detailed vibrational assignments were performed with DFT calculations and the potential energy distribution (PED) obtained from the Vibrational Energy Distribution Analysis (VEDA) program.

  3. Ascertaining neuron importance by information theoretical analysis in motor Brain-Machine Interfaces.

    PubMed

    Wang, Yiwen; Principe, Jose C; Sanchez, Justin C

    2009-01-01

    Point process modeling of neural spike recordings has the potential to capture with high specificity the information contained in spike time occurrence. In Brain-Machine Interfaces (BMIs) the neural tuning characteristic assessed from neural spike recordings can distinguish neuron importance in terms of its modulation with the movement task. Consequently, it improves generalization and reduces significantly computation in previous decoding algorithms, where models reconstruct the kinematics from recorded activities of hundreds of neurons. We propose to apply information theoretical analysis based on an instantaneous tuning model to extract the important neuron subsets for point process decoding on BMI. The cortical distribution of extracted neuron subsets is analyzed and the statistical decoding performance using subset selection is studied with respect to different number of neurons and compared to the one by the full neuron ensemble. With much less computation, the extracted importance neurons provide comparable kinematic reconstructions compared to the full neuron ensemble. The performance of the extracted subset is compared to the random selected subset with same number of neurons to further validate the effectiveness of the subset-extraction approach.

  4. Theoretical analysis of the relationship between positive/negative cooperativity and enzyme activation/inhibition.

    PubMed

    Ge, Hao; Qian, Min

    2009-09-01

    Cooperativity is one of the "paradigms" in enzyme kinetics and molecular biology. But the classical textbook treatment of enzyme kinetics always indeed separates the concepts of positive/negative cooperativity from enzyme activation/inhibition, at least partially. Few theoretical analysis of their relationship has been discussed, although its experimental investigations might date back at least to 1970s. In the present paper, we try to apply the change of free energy as a connective parameter for investigating the relationship between positive/negative cooperativity and enzyme activation/inhibition through several classic equilibrium binding models. It is explicitly shown that the terms of positive/negative cooperativity could be equivalently regarded as enzyme activation/inhibition of the saturation function induced by the substrate molecule itself rather than any other additional effectors. Moreover, both the degree of cooperativity phenomenon and the degree of enzyme activation/inhibition monotonically increase with the change of free energy. Note that this result is quite different from the idea of relating cooperativity to the concepts of "substrate activation/inhibition", which is identified when at high substrate concentrations the reaction rate decreases instead of tending towards the maximum velocity, since it always needs a second substrate molecule.

  5. Parametric sensitivity analysis for stochastic molecular systems using information theoretic metrics

    SciTech Connect

    Tsourtis, Anastasios; Pantazis, Yannis Katsoulakis, Markos A.; Harmandaris, Vagelis

    2015-07-07

    In this paper, we present a parametric sensitivity analysis (SA) methodology for continuous time and continuous space Markov processes represented by stochastic differential equations. Particularly, we focus on stochastic molecular dynamics as described by the Langevin equation. The utilized SA method is based on the computation of the information-theoretic (and thermodynamic) quantity of relative entropy rate (RER) and the associated Fisher information matrix (FIM) between path distributions, and it is an extension of the work proposed by Y. Pantazis and M. A. Katsoulakis [J. Chem. Phys. 138, 054115 (2013)]. A major advantage of the pathwise SA method is that both RER and pathwise FIM depend only on averages of the force field; therefore, they are tractable and computable as ergodic averages from a single run of the molecular dynamics simulation both in equilibrium and in non-equilibrium steady state regimes. We validate the performance of the extended SA method to two different molecular stochastic systems, a standard Lennard-Jones fluid and an all-atom methane liquid, and compare the obtained parameter sensitivities with parameter sensitivities on three popular and well-studied observable functions, namely, the radial distribution function, the mean squared displacement, and the pressure. Results show that the RER-based sensitivities are highly correlated with the observable-based sensitivities.

  6. Comparison of functional network integrity in TBI and orthopedic controlpatientsusing graph-theoretical analysis.

    PubMed

    Karmonik, Christof; Clark, Jessica; Fung, Steve H; Grossman, Robert G; High, Walter; Jiang, Yang

    2013-01-01

    The integrity of functional brain networks inpatients (n=12) diagnosed with traumatic brain injury (TBI) was compared to age-matched subjects (n=12) with orthopedic injury (OI) during a working memory task. A graph-theoretical analysis algorithm was developed and integrated into the AFNI software. Functional networks with correlations between time courses as edge-weights were automatically created and their integrity was quantified by determining the statistical significance of the following network parameters: diameter, density, clustering coefficient, average path length, two largest eigenvalues, spectral density, and minimum eccentricity. Network graphs using a spring-embedded layout (Cytoscape) and a 3D layout integrated into the anatomical space (Paraview) were created. Functional images were composed by color-coding the degree of each voxel (network node) and transformed into Talairach space. Using the AFNI Talairach atlas, degrees of distinct brain regions were quantified. Reduced averaged BOLD responses were found for the TBI group with a higher network integrity potentially as a compensatory mechanism. Regions of high functional connectivity varied in between groups with largest differences in the cerebellum, the temporal lobes and deep brain structures including the lentiform nucleus, caudate and thalamus.

  7. A Detection-Theoretic Analysis of Auditory Streaming and Its Relation to Auditory Masking.

    PubMed

    Chang, An-Chieh; Lutfi, Robert; Lee, Jungmee; Heo, Inseok

    2016-09-18

    Research on hearing has long been challenged with understanding our exceptional ability to hear out individual sounds in a mixture (the so-called cocktail party problem). Two general approaches to the problem have been taken using sequences of tones as stimuli. The first has focused on our tendency to hear sequences, sufficiently separated in frequency, split into separate cohesive streams (auditory streaming). The second has focused on our ability to detect a change in one sequence, ignoring all others (auditory masking). The two phenomena are clearly related, but that relation has never been evaluated analytically. This article offers a detection-theoretic analysis of the relation between multitone streaming and masking that underscores the expected similarities and differences between these phenomena and the predicted outcome of experiments in each case. The key to establishing this relation is the function linking performance to the information divergence of the tone sequences, DKL (a measure of the statistical separation of their parameters). A strong prediction is that streaming and masking of tones will be a common function of DKL provided that the statistical properties of sequences are symmetric. Results of experiments are reported supporting this prediction.

  8. Graph theoretical analysis of sedation's effect on whole brain functional system in school-aged children.

    PubMed

    Wei, Zhen; Alcauter, Sarael; Jin, Ke; Peng, Zi-Wen; Gao, Wei

    2013-01-01

    The neurophysiological mechanism underlying sedation, especially in school-aged children, remains largely unknown. The recently emerged resting-state functional magnetic resonance imaging (rsfMRI) technique, capable of delineating brain's functional interaction pattern among distributed brain areas, proves to be a unique and powerful tool to study sedation-induced brain reorganization. Based on a relatively large school-aged children population (n=28, 10.3±2.6 years, range 7-15 years) and leveraging rsfMRI and graph theoretical analysis, this study aims to delineate sedation-induced changes in brain's information transferring property from a whole brain system perspective. Our results show a global deterioration in brain's efficiency properties (p=0.0085 and 0.0018, for global and local efficiency, respectively) with a locally graded distribution featuring significant disruptions of key consciousness-related regions. Moreover, our results also indicate a redistribution of brain's information-processing hubs characterized by a right and posterior shift as consistent with the reduced level of consciousness during sedation. Overall, our findings inform a sedation-induced functional reorganization pattern in school-aged children that greatly improve our understanding of sedation's effect in children and may potentially serve as reference for future sedation-related experimental studies and clinical applications.

  9. Propagation of a femtosecond pulse in a scattering medium: theoretical analysis and numerical simulation

    SciTech Connect

    Sergeeva, E A; Kirillin, M Yu; Priezzhev, A V

    2006-11-30

    The time profile of a femtosecond pulse propagating in media with a high scattering anisotropy (g{>=}0.9) is studied in detail. The iteration method based on the expansion of the light field in a series in photon scattering orders with the account for the multiply scattered component is proposed to study analytically the structure of a scattered radiation pulse. The small-angle approximation of the radiation transfer theory used for calculations of low-order scatterings is modified to take into account the spread in the photon delay times. The shape of a scattered ultrashort pulse calculated theoretically well agrees with the shape obtained by the Monte-Carlo simulation. It is shown that the pulse profile in a scattering medium depends on the shape of the scattering phase function with the conservation of the anisotropy factor. A comparative analysis of contributions from different scattering orders to the pulse structure is performed depending on the optical properties of a scattering medium. (special issue devoted to multiple radiation scattering in random media)

  10. Structural Network Topology Revealed by White Matter Tractography in Cannabis Users: A Graph Theoretical Analysis

    PubMed Central

    Kim, Dae-Jin; Skosnik, Patrick D.; Cheng, Hu; Pruce, Ben J.; Brumbaugh, Margaret S.; Vollmer, Jennifer M.; Hetrick, William P.; O'Donnell, Brian F.; Sporns, Olaf; Puce, Aina

    2011-01-01

    Abstract Endocannabinoid receptors modulate synaptic plasticity in the brain and may therefore impact cortical connectivity not only during development but also in response to substance abuse in later life. Such alterations may not be evident in volumetric measures utilized in brain imaging, but could affect the local and global organization of brain networks. To test this hypothesis, we used a novel computational approach to estimate network measures of structural brain connectivity derived from diffusion tensor imaging (DTI) and white matter tractography. Twelve adult cannabis (CB) users and 13 healthy subjects were evaluated using a graph theoretic analysis of both global and local brain network properties. Structural brain networks in both CB subjects and controls exhibited robust small-world network attributes in both groups. However, CB subjects showed significantly decreased global network efficiency and significantly increased clustering coefficients (degree to which nodes tend to cluster around individual nodes). CB subjects also exhibited altered patterns of local network organization in the cingulate region. Among all subjects, schizotypal and impulsive personality characteristics correlated with global efficiency but not with the clustering coefficient. Our data indicate that structural brain networks in CB subjects are less efficiently integrated and exhibit altered regional connectivity. These differences in network properties may reflect physiological processes secondary to substance abuse-induced synaptic plasticity, or differences in brain organization that increase vulnerability to substance use. PMID:22432904

  11. Disturbed resting state EEG synchronization in bipolar disorder: A graph-theoretic analysis.

    PubMed

    Kim, Dae-Jin; Bolbecker, Amanda R; Howell, Josselyn; Rass, Olga; Sporns, Olaf; Hetrick, William P; Breier, Alan; O'Donnell, Brian F

    2013-01-01

    Disruption of functional connectivity may be a key feature of bipolar disorder (BD) which reflects disturbances of synchronization and oscillations within brain networks. We investigated whether the resting electroencephalogram (EEG) in patients with BD showed altered synchronization or network properties. Resting-state EEG was recorded in 57 BD type-I patients and 87 healthy control subjects. Functional connectivity between pairs of EEG channels was measured using synchronization likelihood (SL) for 5 frequency bands (δ, θ, α, β, and γ). Graph-theoretic analysis was applied to SL over the electrode array to assess network properties. BD patients showed a decrease of mean synchronization in the alpha band, and the decreases were greatest in fronto-central and centro-parietal connections. In addition, the clustering coefficient and global efficiency were decreased in BD patients, whereas the characteristic path length increased. We also found that the normalized characteristic path length and small-worldness were significantly correlated with depression scores in BD patients. These results suggest that BD patients show impaired neural synchronization at rest and a disruption of resting-state functional connectivity.

  12. Experimental and theoretical analysis of the actuation behavior of magnetoactive elastomers

    NASA Astrophysics Data System (ADS)

    Maas, Jürgen; Uhlenbusch, Dominik

    2016-10-01

    Composites made of an elastomeric matrix and a magnetizable filler, called magnetoactive elastomers (MAEs), are able to undergo a change of their rheological or damping behavior by applying external magnetic fields. Furthermore, these fields lead to actuation forces and deformations of these materials. Consequential, actuation forces and deformations caused by this behavior can be utilized in an actuation mode of the MAE material. To investigate the induced actuation characteristic different cylindrical MAE specimens are described in a first step. In order to perform a measurement of the actuation a suitable test bench is specified and designed. By this test bench a variable external magnetic field has to be provided within an airgap the MAE specimen are placed in. Furthermore, it has to enable a measurement of the induced actuation forces in a specified axial direction on the one hand and the induced elongation in the same direction on the other hand. Subsequently, a theoretical investigation of the described behavior is performed by use of a suitable finite element analysis (FEA). Therefore, an appropriate continuum mechanical modeling approach based on the Kelvin force is introduced. Implementation of this modeling approach within the FEA-tool Comsol Multiphysics enables a coupled simulation of the magnetism and structural-mechanics domain. Finally, an experimental validation of the modeling approach is carried out by measurements using the developed test bench showing a good accordance.

  13. Theoretical analysis of transcranial Hall-effect stimulation based on passive cable model

    NASA Astrophysics Data System (ADS)

    Yuan, Yi; Li, Xiao-Li

    2015-12-01

    Transcranial Hall-effect stimulation (THS) is a new stimulation method in which an ultrasonic wave in a static magnetic field generates an electric field in an area of interest such as in the brain to modulate neuronal activities. However, the biophysical basis of simulating the neurons remains unknown. To address this problem, we perform a theoretical analysis based on a passive cable model to investigate the THS mechanism of neurons. Nerve tissues are conductive; an ultrasonic wave can move ions embedded in the tissue in a static magnetic field to generate an electric field (due to Lorentz force). In this study, a simulation model for an ultrasonically induced electric field in a static magnetic field is derived. Then, based on the passive cable model, the analytical solution for the voltage distribution in a nerve tissue is determined. The simulation results showthat THS can generate a voltage to stimulate neurons. Because the THS method possesses a higher spatial resolution and a deeper penetration depth, it shows promise as a tool for treating or rehabilitating neuropsychiatric disorders. Project supported by the National Natural Science Foundation of China (Grant Nos. 61273063 and 61503321), the China Postdoctoral Science Foundation (Grant No. 2013M540215), the Natural Science Foundation of Hebei Province, China (Grant No. F2014203161), and the Youth Research Program of Yanshan University, China (Grant No. 02000134).

  14. Some Considerations on Simple Non-Linear Magnetic Analysis-Based Optimum Design of Multi-Pole Permanent Magnet Machines

    NASA Astrophysics Data System (ADS)

    Kano, Yoshiaki; Kosaka, Takashi; Matsui, Nobuyuki

    This paper presents a simple non-linear magnetic analysis-based optimum design of a multi-pole permanent magnet machine as an assistant design tool of 3D-FEM. The proposed analysis is based on the equivalent magnetic circuit and the air gap permeance model between the stator and rotor teeth of the motor, taking into account the local magnetic saturation in the pointed end of teeth. The availability of the proposed analysis is verified by comparing with 3D-FEM analysis from the standpoints of the torque calculation accuracy for the variations of design free parameter and the computation time. After verification, the proposed analysis-based optimum design of the dimensions of permanent magnet is examined, by which the minimization of magnet volume is realized while keeping torque/current ratio at the specified value.

  15. Analysis of the THz response of a simple periodic graphite-based structure.

    PubMed

    Colleoni, M P M; Vidal, B

    2014-12-01

    We report the observation of the dichroism effect in simple wire grid structures made of graphite on a paper substrate, i.e. we investigate the feasibility of drawing polarizers for the THz band using conventional graphite-based lead pencils. The displacement of the maximum frequency of the selective absorption phenomenon by varying the wire pitch hints at a polarizing behavior. Measurements of the maximum and minimum of transmission efficiency, extinction ratio and degree of polarization are carried out with a transmission fiber THz-TDS setup. Experimental results show a 9 dB extinction ratio for an inexpensive (<1$) home-made component.

  16. Simple sample digestion of sewage and sludge for multi-element analysis

    SciTech Connect

    Sung, J.F.C.; Nevissi, A.E.; Dewalle, F.B.

    1984-01-01

    A simple digestion method of sewage, sludge, and other materials in sealed ampuls for multi-element determination is reported. The sealed samples are digested in an autoclave at 125/sup 0/C and 1.2 atmosphere pressure for one hour. In a single digestion both volatile and non-volatile elements are recovered. Comparison of this method with conventional hot plate digestion using NBS reference materials, sewage, and sludge, shows equal or better recoveries of the metals in sealed ampuls. The method is not prone to metal contamination and can be used for large numbers of samples.

  17. Phenomenological Analysis of the Kinematic Hardening of HSLA and IF Steels Using Reverse Simple Shear Tests

    SciTech Connect

    Aouafi, A.; Bouvier, S.; Gasperini, M.; Lemoine, X.; Bouaziz, O.

    2007-04-07

    Reverse simple shear tests are used to analyse the Bauschinger effect and the evolution of the kinematic hardening for a wide range of equivalent von Mises strain [0.025 - 0.3]. This work is carried out on two high strength low-alloyed steels. In order to investigate the effect of the precipitates on the macroscopic behaviour, a ferritic mild steel is used as a reference. Different phenomenological descriptions of the back-stress tensor are examined in order to analyse their ability to describe the experimental behaviour.

  18. Theoretical error analysis of the sampling moiré method and phase compensation methodology for single-shot phase analysis.

    PubMed

    Ri, Shien; Muramatsu, Takashi

    2012-06-01

    Recently, a rapid and accurate single-shot phase measurement technique called the sampling moiré method has been developed for small-displacement distribution measurements. In this study, the theoretical phase error of the sampling moiré method caused by linear intensity interpolation in the case of a mismatch between the sampling pitch and the original grating pitch is analyzed. The periodic phase error is proportional to the square of the spatial angular frequency of the moiré fringe. Moreover, an effective phase compensation methodology is developed to reduce the periodic phase error. Single-shot phase analysis can perform accurately even when the sampling pitch is not matched to the original grating pitch exactly. The primary simulation results demonstrate the effectiveness of the proposed phase compensation methodology.

  19. Theoretical analysis of the local field potential in deep brain stimulation applications.

    PubMed

    Lempka, Scott F; McIntyre, Cameron C

    2013-01-01

    Deep brain stimulation (DBS) is a common therapy for treating movement disorders, such as Parkinson's disease (PD), and provides a unique opportunity to study the neural activity of various subcortical structures in human patients. Local field potential (LFP) recordings are often performed with either intraoperative microelectrodes or DBS leads and reflect oscillatory activity within nuclei of the basal ganglia. These LFP recordings have numerous clinical implications and might someday be used to optimize DBS outcomes in closed-loop systems. However, the origin of the recorded LFP is poorly understood. Therefore, the goal of this study was to theoretically analyze LFP recordings within the context of clinical DBS applications. This goal was achieved with a detailed recording model of beta oscillations (∼20 Hz) in the subthalamic nucleus. The recording model consisted of finite element models of intraoperative microelectrodes and DBS macroelectrodes implanted in the brain along with multi-compartment cable models of STN projection neurons. Model analysis permitted systematic investigation into a number of variables that can affect the composition of the recorded LFP (e.g. electrode size, electrode impedance, recording configuration, and filtering effects of the brain, electrode-electrolyte interface, and recording electronics). The results of the study suggest that the spatial reach of the LFP can extend several millimeters. Model analysis also showed that variables such as electrode geometry and recording configuration can have a significant effect on LFP amplitude and spatial reach, while the effects of other variables, such as electrode impedance, are often negligible. The results of this study provide insight into the origin of the LFP and identify variables that need to be considered when analyzing LFP recordings in clinical DBS applications.

  20. Railway noise annoyance: exposure-response relationships and testing a theoretical model by structural equation analysis.

    PubMed

    Pennig, Sibylle; Schady, Arthur

    2014-01-01

    In some regions the exposure to railway noise is extremely concentrated, which may lead to high residential annoyance. Nonacoustical factors contribute to these reactions, but there is limited evidence on the interrelations between the nonacoustical factors that influence railway noise annoyance. The aims of the present study were (1) to examine exposure-response relationships between long-term railway noise exposure and annoyance in a region severely affected by railway noise and (2) to determine a priori proposed interrelations between nonacoustical factors by structural equation analysis. Residents (n = 320) living close to railway tracks in the Middle Rhine Valley completed a socio-acoustic survey. Individual noise exposure levels were calculated by an acoustical simulation model for this area. The derived exposure-response relationships indicated considerably higher annoyance at the same noise exposure level than would have been predicted by the European Union standard curve, particularly for the night-time period. In the structural equation analysis, 72% of the variance in noise annoyance was explained by the noise exposure (L(den)) and nonacoustical variables. The model provides insights into several causal mechanisms underlying the formation of railway noise annoyance considering indirect and reciprocal effects. The concern about harmful effects of railway noise and railway traffic, the perceived control and coping capacity, and the individual noise sensitivity were the most important factors that influence noise annoyance. All effects of the nonacoustical factors on annoyance were mediated by the perceived control and coping capacity and additionally proposed indirect effects of the theoretical model were supported by the data.

  1. Do dynamic effects play a significant role in enzymatic catalysis? A theoretical analysis of formate dehydrogenase.

    PubMed

    Roca, Maite; Oliva, Mónica; Castillo, Raquel; Moliner, Vicente; Tuñón, Iñaki

    2010-10-04

    A theoretical study of the protein dynamic effects on the hydride transfer between the formate anion and nicotinamide adenine dinucleotide (NAD(+)), catalyzed by formate dehydrogenase (FDH), is presented in this paper. The analysis of free downhill molecular dynamic trajectories, performed in the enzyme and compared with the reaction in aqueous solution, has allowed the study of the dynamic coupling between the reacting fragments and the protein or the solvent water molecules, as well as an estimation of the dynamic effect contribution to the catalytic effect from calculation of the transmission coefficient in the enzyme and in solution. The obtained transmission coefficients for the enzyme and in solution were 0.46±0.04 and 0.20±0.03, respectively. These values represent a contribution to catalysis of 0.5 kcal mol(-1), which, although small, is not negligible keeping in mind the low efficiency of FDH. The analysis of the reactive trajectories also reveals how the relative movements of some amino acids, mainly His332 and Arg284, precede and promote the chemical reaction. In spite of these movements, the time-dependent evolution of the electric field created by the enzyme on the key atoms of the reaction reveals a permanent field, which reduces the work required to reach the transition state, with a concomitant polarization of the cofactor. Finally, application of Grote-Hynes theory has allowed the identification of the modes responsible for the substrate-environment coupling, showing how some protein motions take place simultaneously with the reaction. Thus, the equilibrium approach would provide, in this case, an overestimation of the catalyzed rate constant.

  2. Theoretical Analysis of the Local Field Potential in Deep Brain Stimulation Applications

    PubMed Central

    Lempka, Scott F.; McIntyre, Cameron C.

    2013-01-01

    Deep brain stimulation (DBS) is a common therapy for treating movement disorders, such as Parkinson’s disease (PD), and provides a unique opportunity to study the neural activity of various subcortical structures in human patients. Local field potential (LFP) recordings are often performed with either intraoperative microelectrodes or DBS leads and reflect oscillatory activity within nuclei of the basal ganglia. These LFP recordings have numerous clinical implications and might someday be used to optimize DBS outcomes in closed-loop systems. However, the origin of the recorded LFP is poorly understood. Therefore, the goal of this study was to theoretically analyze LFP recordings within the context of clinical DBS applications. This goal was achieved with a detailed recording model of beta oscillations (∼20 Hz) in the subthalamic nucleus. The recording model consisted of finite element models of intraoperative microelectrodes and DBS macroelectrodes implanted in the brain along with multi-compartment cable models of STN projection neurons. Model analysis permitted systematic investigation into a number of variables that can affect the composition of the recorded LFP (e.g. electrode size, electrode impedance, recording configuration, and filtering effects of the brain, electrode-electrolyte interface, and recording electronics). The results of the study suggest that the spatial reach of the LFP can extend several millimeters. Model analysis also showed that variables such as electrode geometry and recording configuration can have a significant effect on LFP amplitude and spatial reach, while the effects of other variables, such as electrode impedance, are often negligible. The results of this study provide insight into the origin of the LFP and identify variables that need to be considered when analyzing LFP recordings in clinical DBS applications. PMID:23555799

  3. Sequential-Injection Analysis: Principles, Instrument Construction, and Demonstration by a Simple Experiment

    ERIC Educational Resources Information Center

    Economou, A.; Tzanavaras, P. D.; Themelis, D. G.

    2005-01-01

    The sequential-injection analysis (SIA) is an approach to sample handling that enables the automation of manual wet-chemistry procedures in a rapid, precise and efficient manner. The experiments using SIA fits well in the course of Instrumental Chemical Analysis and especially in the section of Automatic Methods of analysis provided by chemistry…

  4. Simple proteomics data analysis in the object-oriented PowerShell.

    PubMed

    Mohammed, Yassene; Palmblad, Magnus

    2013-01-01

    Scripting languages such as Perl and Python are appreciated for solving simple, everyday tasks in bioinformatics. A more recent, object-oriented command shell and scripting language, Windows PowerShell, has many attractive features: an object-oriented interactive command line, fluent navigation and manipulation of XML files, ability to consume Web services from the command line, consistent syntax and grammar, rich regular expressions, and advanced output formatting. The key difference between classical command shells and scripting languages, such as bash, and object-oriented ones, such as PowerShell, is that in the latter the result of a command is a structured object with inherited properties and methods rather than a simple stream of characters. Conveniently, PowerShell is included in all new releases of Microsoft Windows and therefore already installed on most computers in classrooms and teaching labs. In this chapter we demonstrate how PowerShell in particular allows easy interaction with mass spectrometry data in XML formats, connection to Web services for tools such as BLAST, and presentation of results as formatted text or graphics. These features make PowerShell much more than "yet another scripting language."

  5. The theoretical, discrete, and actual response of the Barnes objective analysis scheme for one- and two-dimensional fields

    NASA Technical Reports Server (NTRS)

    Pauley, Patricia M.; Wu, Xiaohua

    1990-01-01

    The response of the Barnes objective analysis scheme is studied as a function of wavenumber or wavelength. The first- and second-pass theoretical response functions for continuous two-dimensional fields are derived using Fourier transforms. The results are compared with Barnes' (1973) responses for one-dimensional waves. The continuous theoretical response for one- and two-dimensional waves is compared with the response for discrete applications using uniformly spaced observations for the case where interpolation points and observation points are coincident and for the case where interpolation points are midway between observation points. The actual response of an idealized discrete application of the Barnes scheme is examined, confirming the results of the analysis of the discrete theoretical response.

  6. Theoretical analysis of hydrophobic matching and membrane-mediated interactions in lipid bilayers containing gramicidin.

    PubMed Central

    Harroun, T A; Heller, W T; Weiss, T M; Yang, L; Huang, H W

    1999-01-01

    We present a quantitative analysis of the effects of hydrophobic matching and membrane-mediated protein-protein interactions exhibited by gramicidin embedded in dimyristoylphosphatidylcholine (DMPC) and dilauroylphosphatidylcholine (DLPC) bilayers (Harroun et al., 1999. Biophys. J. 76:937-945). Incorporating gramicidin, at 1:10 peptide/lipid molar ratio, decreases the phosphate-to-phosphate (PtP) peak separation in the DMPC bilayer from 35.3 A without gramicidin to 32.7 A. In contrast, the same molar ratio of gramicidin in DLPC increases the PtP from 30.8 A to 32.1 A. Concurrently, x-ray in-plane scattering showed that the most probable nearest-neighbor separation between gramicidin channels was 26.8 A in DLPC, but reduced to 23.3 A in DMPC. In this paper we review the idea of hydrophobic matching in which the lipid bilayer deforms to match the hydrophobic surface of the embedded proteins. We use a simple elasticity theory, including thickness compression, tension, and splay terms to describe the membrane deformation. The energy of membrane deformation is compared with the energy cost of hydrophobic mismatch. We discuss the boundary conditions between a gramicidin channel and the lipid bilayer. We used a numerical method to solve the problem of membrane deformation profile in the presence of a high density of gramicidin channels and ran computer simulations of 81 gramicidin channels to find the equilibrium distributions of the channels in the plane of the bilayer. The simulations contain four parameters: bilayer thickness compressibility 1/B, bilayer bending rigidity Kc, the channel-bilayer mismatch Do, and the slope of the interface at the lipid-protein boundary s. B, Kc, and Do were experimentally measured; the only free parameter is s. The value of s is determined by the requirement that the theory produces the experimental values of bilayer thinning by gramicidin and the shift in the peak position of the in-plane scattering due to membrane-mediated channel

  7. Chaos and simple determinism in reversed field pinch plasmas: Nonlinear analysis of numerical simulation and experimental data

    SciTech Connect

    Watts, C.A.

    1993-09-01

    In this dissertation the possibility that chaos and simple determinism are governing the dynamics of reversed field pinch (RFP) plasmas is investigated. To properly assess this possibility, data from both numerical simulations and experiment are analyzed. A large repertoire of nonlinear analysis techniques is used to identify low dimensional chaos in the data. These tools include phase portraits and Poincare sections, correlation dimension, the spectrum of Lyapunov exponents and short term predictability. In addition, nonlinear noise reduction techniques are applied to the experimental data in an attempt to extract any underlying deterministic dynamics. Two model systems are used to simulate the plasma dynamics. These are the DEBS code, which models global RFP dynamics, and the dissipative trapped electron mode (DTEM) model, which models drift wave turbulence. Data from both simulations show strong indications of low dimensional chaos and simple determinism. Experimental date were obtained from the Madison Symmetric Torus RFP and consist of a wide array of both global and local diagnostic signals. None of the signals shows any indication of low dimensional chaos or low simple determinism. Moreover, most of the analysis tools indicate the experimental system is very high dimensional with properties similar to noise. Nonlinear noise reduction is unsuccessful at extracting an underlying deterministic system.

  8. Simple and efficient full wave analysis of electromagnetic coupling in multilayer printed circuit board layouts

    NASA Astrophysics Data System (ADS)

    Abdul-Gaffoor, Mohammed Rajeek

    2000-09-01

    A simple method to model Printed Circuit Board (PCB) that takes advantage of the unique features found in PCBs is proposed. This method is capable of analyzing coupling between any nets in the entire multilayer PCB. Using the equivalence principle, the PCB is modeled as a cascade of parallel plate waveguides with half-space regions residing above and below the PCB. The problem is formulated using equivalent magnetic currents in the non- metallic regions of layer interfaces rather than in terms of electric currents in the planar metal layers. The equivalent magnetic currents at the dielectric interfaces are expressed in terms of the Rao-Wilton-Glisson (RWG) basis functions. The electric currents flowing on the vias inside dielectric layers are assumed constant in the vertical direction. These vertical electric currents radiate TEM modes in the parallel plate environment. Integral equations based on simple parallel plate and free-space Green's functions enforcing the boundary conditions are set up and solved using the Method of Moments. The equivalent magnetic currents in each layer interact only with currents in the adjacent layers, thereby resulting in a `` chained-block- banded'' matrix. Excitation is provided through ports defined at each pair of pads, or between a pad and nearby ground. These ports are located on the top and the bottom layers of the PCB where the circuit components and IC pins are mounted. Two different localized excitation schemes, one with a current loop injection and the other with a strip current excitation, are proposed. This formulation requires the computation of the MoM matrix once per frequency for any number of ports. Further, the solution for only those unknown equivalent magnetic currents around the port regions is required to obtain the N-port impedance parameter characterization of the PCB. Consequently, a memory efficient block matrix solution process can be used to solve problems of a large size for a given memory. Simple and

  9. Theoretical Analysis of Amounts of Musical Noise and Speech Distortion in Structure-Generalized Parametric Blind Spatial Subtraction Array

    NASA Astrophysics Data System (ADS)

    Miyazaki, Ryoichi; Saruwatari, Hiroshi; Shikano, Kiyohiro

    We propose a structure-generalized blind spatial subtraction array (BSSA), and the theoretical analysis of the amounts of musical noise and speech distortion. The structure of BSSA should be selected according to the application, i.e., a channelwise BSSA is recommended for listening but a conventional BSSA is suitable for speech recognition.

  10. A simple DNA extraction method for marijuana samples used in amplified fragment length polymorphism (AFLP) analysis.

    PubMed

    Miller Coyle, Heather; Shutler, Gary; Abrams, Sharon; Hanniman, Janet; Neylon, Suzanne; Ladd, Carll; Palmbach, Timothy; Lee, Henry C

    2003-03-01

    As a first step in developing a molecular method for the individualization of marijuana samples, we evaluated a plant DNA extraction kit. The QIAGEN plant DNeasy method uses a spin column format for recovery of DNA and is effective for obtaining high molecular weight DNA from leaf, flower (bud), and seed samples of marijuana. The average DNA yield was 125-500 ng per 100 milligrams of fresh plant tissue. The recovered DNA was of polymerase chain reaction (PCR) quality as measured by the ability to generate reproducible amplified fragment length polymorphism (AFLP) profiles. AFLP is a technique used to create a DNA profile for plant varieties and is being applied to marijuana samples by the authors to link growers and distributors of clonal material. The QIAGEN plant DNeasy method was simple, efficient, and reproducible for processing small quantities of marijuana into DNA.

  11. Analysis of residual chlorine in simple drinking water distribution system with intermittent water supply

    NASA Astrophysics Data System (ADS)

    Goyal, Roopali V.; Patel, H. M.

    2015-09-01

    Knowledge of residual chlorine concentration at various locations in drinking water distribution system is essential final check to the quality of water supplied to the consumers. This paper presents a methodology to find out the residual chlorine concentration at various locations in simple branch network by integrating the hydraulic and water quality model using first-order chlorine decay equation with booster chlorination nodes for intermittent water supply. The explicit equations are developed to compute the residual chlorine in network with a long distribution pipe line at critical nodes. These equations are applicable to Indian conditions where intermittent water supply is the most common system of water supply. It is observed that in intermittent water supply, the residual chlorine at farthest node is sensitive to water supply hours and travelling time of chlorine. Thus, the travelling time of chlorine can be considered to justify the requirement of booster chlorination for intermittent water supply.

  12. Design, analysis and validation of a simple dynamic model of a submerged membrane bioreactor.

    PubMed

    Pimentel, Guilherme A; Vande Wouwer, Alain; Harmand, Jérôme; Rapaport, Alain

    2015-03-01

    In this study, a simple dynamic model of a submerged membrane bioreactor (sMBR) is proposed, which would be suitable for process control. In order to validate the proposed model structure, informative data sets are generated using a detailed simulator built in a well-established environment, namely GPS-X. The model properties are studied, including equilibrium points, stability, and slow/fast dynamics (three different time scales). The existence of slow-fast dynamics is central to the development of a dedicated parameter estimation procedure. Finally, a nonlinear model predictive control is designed to illustrate the potential of the developed model within a model-based control structure. The problem of water treatment in a recirculating aquaculture system is considered as an application example.

  13. Students Learning Physics While Lifting Themselves: A Simple Analysis of a Scissors Jack

    NASA Astrophysics Data System (ADS)

    Haugland, Ole Anton

    2017-02-01

    Every time I have to jack up my car, I am a bit surprised by how slowly the scissors jack works the higher I raise it, and close to maximum height I need very little force to turn the crank. This agrees well with the principle of simple machines. Since I have to jack up my car at least twice a year to change between winter tires and summer tires, I thought it was time to take a closer look at the physics behind the process. And like most physics teachers, I am always looking for new ideas for my teaching. In this note I will present a few ideas on how a jack can be a topic in physics teaching.

  14. Analysis of a Four-Station Doppler Tracking Method Using a Simple CW Beacon

    NASA Technical Reports Server (NTRS)

    Fricke, Clifford L.; Watkins, Carl W. L.

    1961-01-01

    A Doppler tracking method is presented in which a very small, simple CW beacon transmitter is used with four Doppler receiving stations to obtain the position and velocity of a space research vehicle. The exact transmitter frequency need not be known, but an initial position is required, and Doppler frequencies must be measured with extreme accuracy. The errors in the system are analyzed and general formulas are derived for position and velocity errors. The proper location of receiving stations is discussed, a rule for avoiding infinite errors is given, and error charts for ideal station configurations are presented. The effect of the index of refraction is also investigated. The system is capable of determining transmitter position within 1,000 feet at a range of 200 miles.

  15. Statistical analysis of strait time index and a simple model for trend and trend reversal

    NASA Astrophysics Data System (ADS)

    Chen, Kan; Jayaprakash, C.

    2003-06-01

    We analyze the daily closing prices of the Strait Time Index (STI) as well as the individual stocks traded in Singapore's stock market from 1988 to 2001. We find that the Hurst exponent is approximately 0.6 for both the STI and individual stocks, while the normal correlation functions show the random walk exponent of 0.5. We also investigate the conditional average of the price change in an interval of length T given the price change in the previous interval. We find strong correlations for price changes larger than a threshold value proportional to T; this indicates that there is no uniform crossover to Gaussian behavior. A simple model based on short-time trend and trend reversal is constructed. We show that the model exhibits statistical properties and market swings similar to those of the real market.

  16. A simple and efficient error analysis for multi-step solution of the Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Fithen, R. M.

    2002-02-01

    A simple error analysis is used within the context of segregated finite element solution scheme to solve incompressible fluid flow. An error indicator is defined based on the difference between a numerical solution on an original mesh and an approximated solution on a related mesh. This error indicator is based on satisfying the steady-state momentum equations. The advantages of this error indicator are, simplicity of implementation (post-processing step), ability to show regions of high and/or low error, and as the indicator approaches zero the solution approaches convergence. Two examples are chosen for solution; first, the lid-driven cavity problem, followed by the solution of flow over a backward facing step. The solutions are compared to previously published data for validation purposes. It is shown that this rather simple error estimate, when used as a re-meshing guide, can be very effective in obtaining accurate numerical solutions. Copyright

  17. TScratch: a novel and simple software tool for automated analysis of monolayer wound healing assays.

    PubMed

    Gebäck, Tobias; Schulz, Martin Michael Peter; Koumoutsakos, Petros; Detmar, Michael

    2009-04-01

    Cell migration plays a major role in development, physiology, and disease, and is frequently evaluated in vitro by the monolayer wound healing assay. The assay analysis, however, is a time-consuming task that is often performed manually. In order to accelerate this analysis, we have developed TScratch, a new, freely available image analysis technique and associated software tool that uses the fast discrete curvelet transform to automate the measurement of the area occupied by cells in the images. This tool helps to significantly reduce the time needed for analysis and enables objective and reproducible quantification of assays. The software also offers a graphical user interface which allows easy inspection of analysis results and, if desired, manual modification of analysis parameters. The automated analysis was validated by comparing its results with manual-analysis results for a range of different cell lines. The comparisons demonstrate a close agreement for the vast majority of images that were examined and indicate that the present computational tool can reproduce statistically significant results in experiments with well-known cell migration inhibitors and enhancers.

  18. Theoretical analysis of a pressure setting and control system with PWM direction control valve

    NASA Astrophysics Data System (ADS)

    Avram, M.; Duminică, D.; Cartal, L. A.

    2016-08-01

    The paper tackles theoretical aspects concerning an original automated system that sets and controls the pressure inside a tank chamber of fixed volume. The structure of the system integrates an original device developed and designed by the authors. The device digitally controls the one way flow of the working fluid using pulse width modulation, allowing the free flow in the other way. The purpose of this research stage was the theoretical establishing of the variation law of the pressure inside the controlled chamber.

  19. 13C NMR study of halogen bonding of haloarenes: measurements of solvent effects and theoretical analysis.

    PubMed

    Glaser, Rainer; Chen, Naijun; Wu, Hong; Knotts, Nathan; Kaupp, Martin

    2004-04-07

    Solvent effects on the NMR spectra of symmetrical (X = F (1), X = Cl (2), X = Br (3), X = I (4), X = NO2 (5), X = CN (6)) and unsymmetrical (X = I, Y = MeO (7), Y = PhO (8)) para-disubstituted acetophenone azines X-C6H4-CMe=N-N=CMe-C6H4-Y and of models X-C6H4-CMe=N-Z (X = I, Z = H (9), Z = NH2 (10)), 4-iodoacetophenone (11), and iodobenzene (12) were measured in CDCl(3), DMSO, THF, pyridine, and benzene to address one intramolecular and one intermolecular issue. Solvent effects on the (13)C NMR spectra are generally small, and this finding firmly establishes that the azine bridge indeed functions as a "conjugation stopper," an important design concept in our polar materials research. Since intermolecular halogen bonding of haloarenes do occur in polar organic crystalline materials, the NMR solution data pose the question as to whether the absence of solvent shifts indicates the absence of strong halogen bonding in solution. This question was studied by the theoretical analysis of the DMSO complexes of iodoarenes 4, 9-12, and of iodoacetylene. DFT and MP2 computations show iodine bonding, and characteristic structural and electronic features are described. The nonrelativistic complexation shifts and the change in the spin-orbit induced heavy atom effect of iodine compensate each other, and iodine bonding thus has no apparent effect on Ci in the iodoarenes. For iodides, complexation by DMSO occurs and may or may not manifest itself in the NMR spectra. The absence of complexation shifts in the NMR spectra of halides does not exclude the occurrence of halogen bonding in solution.

  20. A theoretical analysis of hemodynamic and biomechanical alterations in intracranial AVMs after radiosurgery

    SciTech Connect

    Lo, E.H. )

    1993-09-20

    Stereotactic radiosurgery is being increasingly used to treat intracranial arteriovenous malformations (AVMs). However, successful radiosurgery may involve latent periods of 1-2 years prior to AVM obliteration. This latent period include states of altered flow patterns that may not influence hemorrhage probabilities. The probability of hemorrhage is likely to be related to the degree of biomechanical stress across the AVM shunt walls. This paper describes a theoretical analysis of the altered hemodynamics and biomechanical stresses within AVM shunts post-radiosurgery. The mathematical model is comprised of linked flow compartments that represent the AVM and adjacent normal vasculature. As obliteration of the irradiated shunts occurs, changes in flow rates and pressure gradients are calculated based on first order fluid dynamics. Stress on the AVM shunt walls is calculated based on tangential forces due to intramural pressure. Two basic models are presented: a distribution of shunts with fixed thin walls subject to step-function obliteration, and a distribution of shunts subject to luminal obliteration from slowly thickening walls. Variations on these models are analyzed, including sequential, selective and random shunt obliteration, and uniform or Poisson distributions of shunt radii. Model I reveals that the range of pressure alterations in the radiosurgically-treated AVM include the possibility of transient increases in the total biomechanical stress within the shunt walls prior to obliteration. Model II demonstrates that uniform luminal narrowing via thickened walls should lead to reduced transmural stresses. The precise temporal pattern of AVM flow decrease and biomechanical stress reduction depends on the selection of shunts that are obliterated. 34 refs., 5 figs., 1 tab.

  1. Brain network of semantic integration in sentence reading: insights from independent component analysis and graph theoretical analysis.

    PubMed

    Ye, Zheng; Doñamayor, Nuria; Münte, Thomas F

    2014-02-01

    A set of cortical and sub-cortical brain structures has been linked with sentence-level semantic processes. However, it remains unclear how these brain regions are organized to support the semantic integration of a word into sentential context. To look into this issue, we conducted a functional magnetic resonance imaging (fMRI) study that required participants to silently read sentences with semantically congruent or incongruent endings and analyzed the network properties of the brain with two approaches, independent component analysis (ICA) and graph theoretical analysis (GTA). The GTA suggested that the whole-brain network is topologically stable across conditions. The ICA revealed a network comprising the supplementary motor area (SMA), left inferior frontal gyrus, left middle temporal gyrus, left caudate nucleus, and left angular gyrus, which was modulated by the incongruity of sentence ending. Furthermore, the GTA specified that the connections between the left SMA and left caudate nucleus as well as that between the left caudate nucleus and right thalamus were stronger in response to incongruent vs. congruent endings.

  2. Environmental analysis of present and future fuels in 2D simple model marine gas tubines

    NASA Astrophysics Data System (ADS)

    El Gohary, M. Morsy

    2013-12-01

    Increased worldwide concerns about fossil fuel costs and effects on the environment lead many governments and scientific societies to consider the hydrogen as the fuel of the future. Many researches have been made to assess the suitability of using the hydrogen gas as fuel for internal combustion engines and gas turbines; this suitability was assessed from several viewpoints including the combustion characteristics, the fuel production and storage and also the thermodynamic cycle changes with the application of hydrogen instead of ordinary fossil fuels. This paper introduces the basic environmental differences happening when changing the fuel of a marine gas turbine from marine diesel fuel to gaseous hydrogen for the same power output. Environmentally, the hydrogen is the best when the CO2 emissions are considered, zero carbon dioxide emissions can be theoretically attained. But when the NOx emissions are considered, the hydrogen is not the best based on the unit heat input. The hydrogen produces 270% more NOx than the diesel case without any control measures. This is primarily due to the increased air flow rate bringing more nitrogen into the combustion chamber and the increased combustion temperature (10% more than the diesel case). Efficient and of course expensive NOx control measures are a must to control these emissions levels.

  3. Theoretical geology

    NASA Astrophysics Data System (ADS)

    Mikeš, Daniel

    2010-05-01

    erroneous assumptions and do not solve the very fundamental issue that lies at the base of the problem. This problem is straighforward and obvious: a sedimentary system is inherently four-dimensional (3 spatial dimensions + 1 temporal dimension). Any method using an inferior number or dimensions is bound to fail to describe the evolution of a sedimentary system. It is indicative of the present day geological world that such fundamental issues be overlooked. The only reason for which one can appoint the socalled "rationality" in todays society. Simple "common sense" leads us to the conclusion that in this case the empirical method is bound to fail and the only method that can solve the problem is the theoretical approach. Reasoning that is completely trivial for the traditional exact sciences like physics and mathematics and applied sciences like engineering. However, not for geology, a science that was traditionally descriptive and jumped to empirical science, skipping the stage of theoretical science. I argue that the gap of theoretical geology is left open and needs to be filled. Every discipline in geology lacks a theoretical base. This base can only be filled by the theoretical/inductive approach and can impossibly be filled by the empirical/deductive approach. Once a critical mass of geologists realises this flaw in todays geology, we can start solving the fundamental problems in geology.

  4. Deployment Analysis of a Simple Tape-Spring Hinge Using Probabilistic Methods

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Horta, Lucas G.

    2012-01-01

    Acceptance of new deployable structures architectures and concepts requires validated design methods to minimize the expense involved with technology validation flight testing. Deployable concepts for large lightweight spacecraft include booms, antennae, and masts. This paper explores the implementation of probabilistic methods in the design process for the deployment of a strain-energy mechanism, specifically a simple tape-spring hinge. Strain-energy mechanisms are attractive for deployment in very lightweight systems because they do not require the added mass and complexity associated with motors and controllers. However, designers are hesitant to include free deployment, strain-energy mechanisms because of the potential for uncontrolled behavior. In the example presented here, the tapespring cross-sectional dimensions have been varied and a target displacement during deployment has been selected as the design metric. Specifically, the tape-spring should reach the final position in the shortest time with the minimal amount of overshoot and oscillations. Surrogate models have been used to reduce computational expense. Parameter values to achieve the target response have been computed and used to demonstrate the approach. Based on these results, the application of probabilistic methods for design of a tape-spring hinge has shown promise as a means of designing strain-energy components for more complex space concepts.

  5. Simple Fall Criteria for MEMS Sensors: Data Analysis and Sensor Concept

    PubMed Central

    Ibrahim, Alwathiqbellah; Younis, Mohammad I.

    2014-01-01

    This paper presents a new and simple fall detection concept based on detailed experimental data of human falling and the activities of daily living (ADLs). Establishing appropriate fall algorithms compatible with MEMS sensors requires detailed data on falls and ADLs that indicate clearly the variations of the kinematics at the possible sensor node location on the human body, such as hip, head, and chest. Currently, there is a lack of data on the exact direction and magnitude of each acceleration component associated with these node locations. This is crucial for MEMS structures, which have inertia elements very close to the substrate and are capacitively biased, and hence, are very sensitive to the direction of motion whether it is toward or away from the substrate. This work presents detailed data of the acceleration components on various locations on the human body during various kinds of falls and ADLs. A two-degree-of-freedom model is used to help interpret the experimental data. An algorithm for fall detection based on MEMS switches is then established. A new sensing concept based on the algorithm is proposed. The concept is based on employing several inertia sensors, which are triggered simultaneously, as electrical switches connected in series, upon receiving a true fall signal. In the case of everyday life activities, some or no switches will be triggered resulting in an open circuit configuration, thereby preventing false positive. Lumped-parameter model is presented for the device and preliminary simulation results are presented illustrating the new device concept. PMID:25006997

  6. A simple model for deep tissue attenuation correction and large organ analysis of Cerenkov luminescence imaging

    NASA Astrophysics Data System (ADS)

    Habte, Frezghi; Natarajan, Arutselvan; Paik, David S.; Gambhir, Sanjiv S.

    2014-03-01

    Cerenkov luminescence imaging (CLI) is an emerging cost effective modality that uses conventional small animal optical imaging systems and clinically available radionuclide probes for light emission. CLI has shown good correlation with PET for organs of high uptake such as kidney, spleen, thymus and subcutaneous tumors in mouse models. However, CLI has limitations for deep tissue quantitative imaging since the blue-weighted spectral characteristics of Cerenkov radiation attenuates highly by mammalian tissue. Large organs such as the liver have also shown higher signal due to the contribution of emission of light from a greater thickness of tissue. In this study, we developed a simple model that estimates the effective tissue attenuation coefficient in order to correct the CLI signal intensity with a priori estimated depth and thickness of specific organs. We used several thin slices of ham to build a phantom with realistic attenuation. We placed radionuclide sources inside the phantom at different tissue depths and imaged it using an IVIS Spectrum (Perkin-Elmer, Waltham, MA, USA) and Inveon microPET (Preclinical Solutions Siemens, Knoxville, TN). We also performed CLI and PET of mouse models and applied the proposed attenuation model to correct CLI measurements. Using calibration factors obtained from phantom study that converts the corrected CLI measurements to %ID/g, we obtained an average difference of less that 10% for spleen and less than 35% for liver compared to conventional PET measurements. Hence, the proposed model has a capability of correcting the CLI signal to provide comparable measurements with PET data.

  7. Simple fall criteria for MEMS sensors: data analysis and sensor concept.

    PubMed

    Ibrahim, Alwathiqbellah; Younis, Mohammad I

    2014-07-08

    This paper presents a new and simple fall detection concept based on detailed experimental data of human falling and the activities of daily living (ADLs). Establishing appropriate fall algorithms compatible with MEMS sensors requires detailed data on falls and ADLs that indicate clearly the variations of the kinematics at the possible sensor node location on the human body, such as hip, head, and chest. Currently, there is a lack of data on the exact direction and magnitude of each acceleration component associated with these node locations. This is crucial for MEMS structures, which have inertia elements very close to the substrate and are capacitively biased, and hence, are very sensitive to the direction of motion whether it is toward or away from the substrate. This work presents detailed data of the acceleration components on various locations on the human body during various kinds of falls and ADLs. A two-degree-of-freedom model is used to help interpret the experimental data. An algorithm for fall detection based on MEMS switches is then established. A new sensing concept based on the algorithm is proposed. The concept is based on employing several inertia sensors, which are triggered simultaneously, as electrical switches connected in series, upon receiving a true fall signal. In the case of everyday life activities, some or no switches will be triggered resulting in an open circuit configuration, thereby preventing false positive. Lumped-parameter model is presented for the device and preliminary simulation results are presented illustrating the new device concept.

  8. Quantitative proteomic analysis reveals a simple strategy of global resource allocation in bacteria.

    PubMed

    Hui, Sheng; Silverman, Josh M; Chen, Stephen S; Erickson, David W; Basan, Markus; Wang, Jilong; Hwa, Terence; Williamson, James R

    2015-02-12

    A central aim of cell biology was to understand the strategy of gene expression in response to the environment. Here, we study gene expression response to metabolic challenges in exponentially growing Escherichia coli using mass spectrometry. Despite enormous complexity in the details of the underlying regulatory network, we find that the proteome partitions into several coarse-grained sectors, with each sector's total mass abundance exhibiting positive or negative linear relations with the growth rate. The growth rate-dependent components of the proteome fractions comprise about half of the proteome by mass, and their mutual dependencies can be characterized by a simple flux model involving only two effective parameters. The success and apparent generality of this model arises from tight coordination between proteome partition and metabolism, suggesting a principle for resource allocation in proteome economy of the cell. This strategy of global gene regulation should serve as a basis for future studies on gene expression and constructing synthetic biological circuits. Coarse graining may be an effective approach to derive predictive phenomenological models for other 'omics' studies.

  9. Acylation of Chiral Alcohols: A Simple Procedure for Chiral GC Analysis

    PubMed Central

    Oromí-Farrús, Mireia; Torres, Mercè; Canela, Ramon

    2012-01-01

    The use of iodine as a catalyst and either acetic or trifluoroacetic acid as a derivatizing reagent for determining the enantiomeric composition of acyclic and cyclic aliphatic chiral alcohols was investigated. Optimal conditions were selected according to the molar ratio of alcohol to acid, the reaction time, and the reaction temperature. Afterwards, chiral stability of chiral carbons was studied. Although no isomerization was observed when acetic acid was used, partial isomerization was detected with the trifluoroacetic acid. A series of chiral alcohols of a widely varying structural type were then derivatized with acetic acid using the optimal conditions. The resolution of the enantiomeric esters and the free chiral alcohols was measured using a capillary gas chromatograph equipped with a CP Chirasil-DEX CB column. The best resolutions were obtained with 2-pentyl acetates (α = 3.00) and 2-hexyl acetates (α = 1.95). This method provides a very simple and efficient experimental workup procedure for analyzing chiral alcohols by chiral-phase GC. PMID:22649749

  10. Analysis of simple tandem repeat (STR) marker allele distributions in a Balinese population

    SciTech Connect

    Morell, R.; Ashler, J.H.; Friedman, T.B.

    1994-09-01

    Genotypes for 53 simple tandem repeat (STR) markers distributed at greater than 39 cM intervals throughout the genome were determined for 46 individuals from the village of Bengkala, Bali. This village dates to at least the thirteenth century, has approximately 2,200 individuals and has an oral and written tradition suggesting genetic bottlenecks. The allele frequency distributions in Bengkala were compared with distributions obtained by typing individuals in the CEPH data base using a Kolmogorov-Smirnov two sample test. Twenty-eight of the 53 markers showed differences (p<0.05) in distribution between the two populations. Allele frequencies of tetranucleotide STRs were much more similar between the two populations than were those of dinucleotide STRs (p < 0.0043). This may be due to the higher mutation rate of tetranucleotide STRs, combining with selection on repeat lengths, to produce a {open_quotes}stable{close_quotes} allele distribution. Population heterogeneity in Bengkala was indicated by an excess of observed homozygosity, deviations from Hardy-Weinberg equilibrium at seven loci, and significant genotypic disequilibrium between physically unlinked loci. These analyses serve as a resource to map a gene causing non-syndromal autosomal recessive deafness in Bengkala, and to corroborate the anthropological study of the history and social structure of the village.

  11. Development of simple sequence repeat markers and diversity analysis in alfalfa (Medicago sativa L.).

    PubMed

    Wang, Zan; Yan, Hongwei; Fu, Xinnian; Li, Xuehui; Gao, Hongwen

    2013-04-01

    Efficient and robust molecular markers are essential for molecular breeding in plant. Compared to dominant and bi-allelic markers, multiple alleles of simple sequence repeat (SSR) markers are particularly informative and superior in genetic linkage map and QTL mapping in autotetraploid species like alfalfa. The objective of this study was to enrich SSR markers directly from alfalfa expressed sequence tags (ESTs). A total of 12,371 alfalfa ESTs were retrieved from the National Center for Biotechnology Information. Total 774 SSR-containing ESTs were identified from 716 ESTs. On average, one SSR was found per 7.7 kb of EST sequences. Tri-nucleotide repeats (48.8 %) was the most abundant motif type, followed by di-(26.1 %), tetra-(11.5 %), penta-(9.7 %), and hexanucleotide (3.9 %). One hundred EST-SSR primer pairs were successfully designed and 29 exhibited polymorphism among 28 alfalfa accessions. The allele number per marker ranged from two to 21 with an average of 6.8. The PIC values ranged from 0.195 to 0.896 with an average of 0.608, indicating a high level of polymorphism of the EST-SSR markers. Based on the 29 EST-SSR markers, assessment of genetic diversity was conducted and found that Medicago sativa ssp. sativa was clearly different from the other subspecies. The high transferability of those EST-SSR markers was also found for relative species.

  12. The simple fool's guide to population genomics via RNA-Seq: an introduction to high-throughput sequencing data analysis.

    PubMed

    De Wit, Pierre; Pespeni, Melissa H; Ladner, Jason T; Barshis, Daniel J; Seneca, François; Jaris, Hannah; Therkildsen, Nina Overgaard; Morikawa, Megan; Palumbi, Stephen R

    2012-11-01

    High-throughput sequencing technologies are currently revolutionizing the field of biology and medicine, yet bioinformatic challenges in analysing very large data sets have slowed the adoption of these technologies by the community of population biologists. We introduce the 'Simple Fool's Guide to Population Genomics via RNA-seq' (SFG), a document intended to serve as an easy-to-follow protocol, walking a user through one example of high-throughput sequencing data analysis of nonmodel organisms. It is by no means an exhaustive protocol, but rather serves as an introduction to the bioinformatic methods used in population genomics, enabling a user to gain familiarity with basic analysis steps. The SFG consists of two parts. This document summarizes the steps needed and lays out the basic themes for each and a simple approach to follow. The second document is the full SFG, publicly available at http://sfg.stanford.edu, that includes detailed protocols for data processing and analysis, along with a repository of custom-made scripts and sample files. Steps included in the SFG range from tissue collection to de novo assembly, blast annotation, alignment, gene expression, functional enrichment, SNP detection, principal components and F(ST) outlier analyses. Although the technical aspects of population genomics are changing very quickly, our hope is that this document will help population biologists with little to no background in high-throughput sequencing and bioinformatics to more quickly adopt these new techniques.

  13. Theoretical and experimental analysis of a multiphase screw pump, handling gas-liquid mixtures with very high gas volume fractions

    SciTech Connect

    Raebiger, K.; Maksoud, T.M.A.; Ward, J.; Hausmann, G.

    2008-09-15

    In the investigation of the pumping behaviour of multiphase screw pumps, handling gas-liquid mixtures with very high gas volume fractions, theoretical and experimental analyses were performed. A new theoretical screw pump model was developed, which calculates the time-dependent conditions inside the several chambers of a screw pump as well as the exchange of mass and energy between these chambers. By means of the performed experimental analysis, the screw pump model was verified, especially at very high gas volume fractions from 90% to 99%. The experiments, which were conducted with the reference fluids water and air, can be divided mainly into the determination of the steady state pumping behaviour on the one hand and into the analysis of selected transient operating conditions on the other hand, whereas the visualisation of the leakage flows through the circumferential gaps was rounded off the experimental analysis. (author)

  14. Simple Analysis Used in Diagnosis and Follow-up of Schizophrenic Patients (Patent)

    PubMed Central

    Nour El-Dien, Faten A.; El-Nahas, Reham G.; El-Nahas, Ahmed G.

    2006-01-01

    Dopamine acts as neurotransmitter in the central and peripheral sympathetic nervous system. Determination of dopamine (DO) was performed by spectrophotometric analysis depending on the formation of new colored compound. The proposed procedure was efficient in quantitative determination of DO as pure material in pharmaceutical preparations and in urine samples. DO concentration in urine sample of patient confirms the affection with schizophrenia and the proposed procedure was used to facilitate diagnosis and followup of schizophrenic patients. It is recommended to apply the proposed procedures as routine analysis in pharmaceutical companies for quality control and in analytical laboratories to diagnose and follow up schizophrenia. PMID:17671624

  15. Genome-wide analysis of simple sequence repeats in the model medicinal mushroom Ganoderma lucidum.

    PubMed

    Qian, Jun; Xu, Haibin; Song, Jingyuan; Xu, Jiang; Zhu, Yingjie; Chen, Shilin

    2013-01-10

    Simple sequence repeats (SSRs) or microsatellites are one of the most popular sources of genetic markers and play a significant role in gene function and genome organization. We identified SSRs in the genome of Ganoderma lucidum and analyzed their frequency and distribution in different genomic regions. We also compared the SSRs in G. lucidum with six other Agaricomycetes genomes: Coprinopsis cinerea, Laccaria bicolor, Phanerochaete chrysosporium, Postia placenta, Schizophyllum commune and Serpula lacrymans. Based on our search criteria, the total number of SSRs found ranged from 1206 to 6104 and covered from 0.04% to 0.15% of the fungal genomes. The SSR abundance was not correlated with the genome size, and mono- to tri-nucleotide repeats outnumbered other SSR categories in all of the species examined. In G. lucidum, a repertoire of 2674 SSRs was detected, with mono-nucleotides being the most abundant. SSRs were found in all genomic regions and were more abundant in non-coding regions than coding regions. The highest SSR relative abundance was found in introns (108 SSRs/Mb), followed by intergenic regions (84 SSRs/Mb). A total of 684 SSRs were found in the protein-coding sequences (CDSs) of 588 gene models, with 81.4% of them being tri- or hexa-nucleotides. After scanning for InterPro domains, 280 of these genes were successfully annotated, and 215 of them could be assigned to Gene Ontology (GO) terms. SSRs were also identified in 28 bioactive compound synthesis-related gene models, including one 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), three polysaccharide biosynthesis genes and 24 cytochrome P450 monooxygenases (CYPs). Primers were designed for the identified SSR loci, providing the basis for the future development of SSR markers of this medicinal fungus.

  16. Theoretical and experimental analysis of a piezoelectric plate connected to a negative capacitance at MHz frequencies

    NASA Astrophysics Data System (ADS)

    Mansoura, S. A.; Benard, P.; Morvan, B.; Maréchal, P.; Hladky-Hennion, A.-C.; Dubus, B.

    2015-11-01

    In this paper, a theoretical and experimental study of the electric impedance of a piezoelectric plate connected to a negative capacitance is performed in the MHz frequency range. The negative capacitance is realized with a circuit using current conveyors (CCII+). This circuit allows us to achieve important values of negative capacitance, of the same order of the static capacitance of the piezoelectric plate studied. Mason’s model is considered for the theoretical characterization of the piezoelectric plate connected to the negative capacitance circuit. The experimental results show a large tunability of the frequency of the piezoelectric parallel resonance over a range of 1.1 MHz to 1.28 MHz. Moreover, according to the value of the negative capacitance, the effective electromechanical coupling factor of the piezoelectric plate is evaluated. With a very good agreement with the theoretical estimation, an increase of approximately 50% of the effective electromechanical coupling factor is experimentally measured.

  17. Quantitative Analysis of Organic Compounds: A Simple and Rapid Method for Use in Schools

    ERIC Educational Resources Information Center

    Schmidt, Hans-Jurgen

    1973-01-01

    Describes the procedure for making a quantitative analysis of organic compounds suitable for secondary school chemistry classes. Using the Schoniger procedure, the organic compound, such as PVC, is decomposed in a conical flask with oxygen. The products are absorbed in a suitable liquid and analyzed by titration. (JR)

  18. Clear & Simple

    MedlinePlus

    ... the audience themselves. It is important to get direct audience involvement at some point to test the ... words are defined clearly. Sentences are simple, specific, direct, and written in the active voice. Each idea ...

  19. Theoretical analysis for critical fluctuations of relaxation trajectory near a saddle-node bifurcation.

    PubMed

    Iwata, Mami; Sasa, Shin-ichi

    2010-07-01

    A Langevin equation whose deterministic part undergoes a saddle-node bifurcation is investigated theoretically. It is found that statistical properties of relaxation trajectories in this system exhibit divergent behaviors near a saddle-node bifurcation point in the weak-noise limit, while the final value of the deterministic solution changes discontinuously at the point. A systematic formulation for analyzing a path probability measure is constructed on the basis of a singular perturbation method. In this formulation, the critical nature turns out to originate from the neutrality of exiting time from a saddle point. The theoretical calculation explains results of numerical simulations.

  20. Theoretical analysis of south-staring Beampark configurations for the TIRA system

    NASA Astrophysics Data System (ADS)

    Flegel, S.; Letsch, K.; Krag, H.

    2015-09-01

    The tracking and imaging radar (TIRA) L-band radar of the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) in Wachtberg has been used since 1993 for the conduction of space debris measurement campaigns, called Beampark experiments (BPE). The results from BPEs are used for the regular validation of statistical debris models such as ESA's MASTER model. It is an experimental radar system which is employed among other things in the frame of BPEs. In these experiments, the line-of-sight (LOS) of the radar is fixed at a defined direction and measurements are taken for 24 h. The aim of these campaigns is to obtain statistical information on the state of the space debris environment in Low Earth Orbit. BPEs are typically conducted in mono-static east-staring mode. The aim of the current paper is to gain an overview of how the measurement results of mono-static BPEs using TIRA are influenced by the direction of the LOS with a focus on south-staring BPEs. The analysis is purely theoretical and employs ESA's Program for Radar and Optical Observation Forecasting (PROOF-2009). The paper starts out with a look at the range window as a function of the LOS elevation which is required to cover LEO altitudes up to 2000 km. This information is required to determine the minimum allowed pulse repetition interval necessary to obtain unambiguous range information. In a next step, 24 h BPEs are simulated covering azimuth angles between 0° and 360° and elevation angles between 10° and 90°. Looking at the number of crossings and detections at various object sizes, orbit types and debris sources allows an assessment of specific LOS orientations. Due to the relatively high latitude of the sensor at about 50° north, debris at low inclinations can only be detected if the radar's LOS is directed due south. The lower the LOS elevation is, the more objects on low inclination orbits will cross TIRA's beam. A low LOS elevation however requires an extended range window

  1. Simple and suitable immunosensor for β-lactam antibiotics analysis in real matrixes: milk, serum, urine.

    PubMed

    Merola, Giovanni; Martini, Elisabetta; Tomassetti, Mauro; Campanella, Luigi

    2015-03-15

    The anti-penicillin G was conjugated to avidin-peroxidase and biotin to obtain immunogen and competitor which were then used to develop a competitive immunosensor assay for the detection of penicillin G and other β-lactam antibiotics, with Kaff values of the order of 10(8) M(-1). The new immunosensor appears to afford a number of advantages in terms of sensitivity, possibility of "in situ" analysis, but especially of simplicity and lower costs, compared with other existing devices, or different chemical instrumental methods reported in the literature and used for the analysis of β-lactam compounds. Satisfactory results were found in the analysis of real matrixes and good recoveries were obtained by applying the standard addition method to spiked milk, urine, serum and drug samples. The new device uses an amperometric electrode for hydrogen peroxide as transducer, the BSA-penicillin G immobilized on polymeric membrane overlapping the amperometric transducer and the peroxidase enzyme as marker. It proved to be highly sensitive, inexpensive and easily reproducible; LOD was of the order of 10(-11)M. Lastly, the new immunosensor displayed low selectivity versus the entire class of β-lactam antibiotics and higher selectivity toward other classes of non-β-lactam antibiotics.

  2. Following the enzymatic digestion of chondroitin sulfate by a simple GPC analysis.

    PubMed

    Silva, Carla; Novoa-Carballal, Ramon; Reis, Rui L; Pashkuleva, Iva

    2015-07-23

    We describe the use of gel permeation chromatography (GPC) setup with four size exclusion columns for analysis of enzymatically digested glycosaminoglycans (GAGs). This setup provides information about the molecular weight (Mw) and concentration of all species (low and high Mw) present in the digests in a single measurement. The data about the fraction with high Mw (often omitted in the analysis of GAG digests) provide direct evidence about the mechanisms of action of the enzymes. We proved the feasibility of this methodology by applying it to chondroitin sulfate (CS) substrates with different molecular weight and sulfation pattern and using different enzymes (hyaluronidase and chondroitinase). NMR analysis of the obtained digests fractionated by ultrafiltration confirmed the results obtained by GPC setup and reveal further details about the degradation mechanisms: (i) both enzymes preferentially attack 4-sulfated chondroitin and (ii) additionally to the well documented endolytic activity of hyaluronidase we also observed a low lyase activity for this enzyme reflected in the detected minor exolytic breakage. Finally, we demonstrate that CS with medium molecular weight (12-60kDa) which is sulfated mainly at 6-position can be obtained in good yields by enzymatic digestion and following ultrafiltration.

  3. SCBUCKLE user's manual: Buckling analysis program for simple supported and clamped panels

    NASA Technical Reports Server (NTRS)

    Cruz, Juan R.

    1993-01-01

    The program SCBUCKLE calculates the buckling loads and mode shapes of cylindrically curved, rectangular panels. The panel is assumed to have no imperfections. SCBUCKLE is capable of analyzing specially orthotropic symmetric panels (i.e., A(sub 16) = A(sub 26) = 0.0, D(sub 16) = D(sub 26) = 0.0, B(sub ij) = 0.0). The analysis includes first-order transverse shear theory and is capable of modeling sandwich panels. The analysis supports two types of boundary conditions: either simply supported or clamped on all four edges. The panel can be subjected to linearly varying normal loads N(sub x) and N(sub y) in addition to a constant shear load N(sub xy). The applied loads can be divided into two parts: a preload component; and a variable (eigenvalue-dependent) component. The analysis is based on the modified Donnell's equations for shallow shells. The governing equations are solved by Galerkin's method.

  4. The limitations of simple gene set enrichment analysis assuming gene independence.

    PubMed

    Tamayo, Pablo; Steinhardt, George; Liberzon, Arthur; Mesirov, Jill P

    2016-02-01

    Since its first publication in 2003, the Gene Set Enrichment Analysis method, based on the Kolmogorov-Smirnov statistic, has been heavily used, modified, and also questioned. Recently a simplified approach using a one-sample t-test score to assess enrichment and ignoring gene-gene correlations was proposed by Irizarry et al. 2009 as a serious contender. The argument criticizes Gene Set Enrichment Analysis's nonparametric nature and its use of an empirical null distribution as unnecessary and hard to compute. We refute these claims by careful consideration of the assumptions of the simplified method and its results, including a comparison with Gene Set Enrichment Analysis's on a large benchmark set of 50 datasets. Our results provide strong empirical evidence that gene-gene correlations cannot be ignored due to the significant variance inflation they produced on the enrichment scores and should be taken into account when estimating gene set enrichment significance. In addition, we discuss the challenges that the complex correlation structure and multi-modality of gene sets pose more generally for gene set enrichment methods.

  5. Theoretical analysis of condensation in the presence of noncondensable gases as applied to open cycle OTEC condensers

    NASA Astrophysics Data System (ADS)

    Panchal, C. B.; Bell, K. J.

    The open cycle ocean thermal energy conversion condenser was analyzed from a theoretical standpoint. Interfacial temperature profiles and gas concentrations in the axial direction were determined, and their effects on the rate of condensation studied. For the analysis, the vapor phase was modeled using diffusion equations for simultaneous heat and mass transfer processes, while the liquid phase was modeled using a falling film analysis. This analysis was then applied to a plate fin condenser, and the effect of varying the fin density along the condenser lengths was investigated. General engineering aspects of heat exchanger design are discussed for condensation of vapor mixtures in the presence of noncondensable gases.

  6. Adjectives That Aren't: An ERP-Theoretical Analysis of Adjectives in Spanish

    ERIC Educational Resources Information Center

    Bartlett, Laura B.

    2013-01-01

    This thesis investigates the syntactic status of adjectives in Spanish through a crossdisciplinary perspective, incorporating methodologies from both theoretical linguistics and neurolinguistics, specifically, event-related potentials (ERPs). It presents conflicting theories about the syntax of adjectives and explores the ways that the processing…

  7. Rethinking High School Principal Compensation Practices: An Analysis of Salaries in South Carolina and Theoretical Models

    ERIC Educational Resources Information Center

    Newman, Tim A.

    2012-01-01

    This study described the current state of principal salaries in South Carolina and compared the salaries of similar size schools by specific report card performance and demographic variables. Based on the findings, theoretical models were proposed, and comparisons were made with current salary data. School boards, human resource personnel and…

  8. Falling Chains as Variable-Mass Systems: Theoretical Model and Experimental Analysis

    ERIC Educational Resources Information Center

    de Sousa, Celia A.; Gordo, Paulo M.; Costa, Pedro

    2012-01-01

    In this paper, we revisit, theoretically and experimentally, the fall of a folded U-chain and of a pile-chain. The model calculation implies the division of the whole system into two subsystems of variable mass, allowing us to explore the role of tensional contact forces at the boundary of the subsystems. This justifies, for instance, that the…

  9. Detailed theoretical and experimental analysis of low-energy electron-N2 scattering

    NASA Astrophysics Data System (ADS)

    Sun, Weiguo; Morrison, Michael A.; Isaacs, William A.; Trail, Wayne K.; Alle, Dean T.; Gulley, R. J.; Brennan, Michael J.; Buckman, Stephen J.

    1995-08-01

    We have carried out a comprehensive theoretical and experimental study of electron scattering from molecular nitrogen at energies below 10.0 eV. In the theoretical component of this project we have generated differential and integral cross sections for elastic scattering and vibrational excitation in converged vibrational close-coupling calculations. In the experiments, we have measured differential cross sections for these processes at scattering angles from 20° to 130° in a crossed-beam experiment at a large number of energies between 0.55 and 10 eV and, in a complementary time-of-flight experiment, total cross sections at energies between 0.08 and 10.0 eV. The measured angular distributions have been extrapolated to 0° and 180° using a procedure based on a nonlinear least-squares fit constrained by known physical properties of the e-N2 scattering matrix; numerical integration of the resulting extrapolated distributions yields integrated cross sections with almost no error beyond that inherent in the measured angular data. We find generally good agreement between the present experimental and theoretical cross section, particularly at energies near the Πg resonance near 2.39 eV. In previous studies of scattering in this region, such comparisons have been made problematical by the difficulty of ascertaining the appropriate theoretical scattering energy. We recommend here a protocol for resolving this problem for both elastic scattering and vibrational excitation.

  10. A Critical Analysis of Approaches To Targeted PTSD Prevention: Current Status and Theoretically Derived Future Directions

    ERIC Educational Resources Information Center

    Feldner, Matthew T.; Monson, Candice M.; Friedman, Matthew J.

    2007-01-01

    Although efforts to prevent posttraumatic stress disorder (PTSD) have met with relatively limited success, theoretically driven preventive approaches with promising efficacy are emerging. The current article critically reviews investigations of PTSD prevention programs that target persons at risk for being exposed to a traumatic event or who have…

  11. A Preliminary Theoretical Analysis of a Research Experience for Undergraduates Community Model

    ERIC Educational Resources Information Center

    Castillo-Garsow, Carlos; Castillo-Chavez, Carlos; Woodley, Sherry

    2013-01-01

    The Mathematical and Theoretical Biology Institute (MTBI) is a successful summer research experience for undergraduates, with a strong record of mentoring Ph.D. graduates, particularly, underrepresented minority students. However, the MTBI program was designed for education in research, not for research in education, and the mechanisms of the…

  12. A Historical Analysis of Academic Development Using the Theoretical Lens of Pierre Bourdieu

    ERIC Educational Resources Information Center

    Kloot, Bruce Charles

    2015-01-01

    This paper provides a history of academic development by examining how a South African institution coped with the potent social forces confronting it before the collapse of apartheid. Theoretically, it draws on the framework of Pierre Bourdieu and engages with a paper written a decade ago by Naidoo, who also used Bourdieu to understand…

  13. Microstructure analysis of dental castings used in fixed dental prostheses--a simple method for quality control.

    PubMed

    Mehl, Christian; Lang, Björn; Kappert, Heinrich; Kern, Matthias

    2011-06-01

    The aim of this study was to evaluate the microstructural quality of noble alloy castings from commercial dental laboratories using the wiping-etching method as a simple method for quality control. In total, 240 castings from two noble alloys (AuAgCuPt and AuPtZn) were taken from a day's production of five different dental laboratories. The casting quality was evaluated by determining the grain size and by assessing the number and size of shrinkage cavities after acidic etching of the alloy surfaces. The AuAgCuPt alloy castings showed an acceptable quality in the microstructural analysis. The results of AuPtZn castings, however, were not satisfactory because 50.8% of the samples showed a remarkably poorer quality compared to the specifications made by the manufacturer. The proportion of the employed reclaimed alloy had no influence on the casting quality when AuAgCuPt alloy was used, but was influential when casting restorations with AuPtZn alloy. When determining the quantity and size of shrinkage cavities, none of the evaluated castings was of such a poor quality that a replacement of the castings had to be considered. The differences in grain size and quantity of shrinkage cavities were reflecting the individual laboratory process rather than the admixture of new/reclaimed alloy. The presented analysis can be used as a simple method for quality control of dental castings.

  14. A Simple Engineering Analysis of Solar Particle Event High Energy Tails and Their Impact on Vehicle Design

    NASA Technical Reports Server (NTRS)

    Singleterry, Robert C., Jr.; Walker, Steven A.; Clowdsley, Martha S.

    2016-01-01

    The mathematical models for Solar Particle Event (SPE) high energy tails are constructed with several di erent algorithms. Since limited measured data exist above energies around 400 MeV, this paper arbitrarily de nes the high energy tail as any proton with an energy above 400 MeV. In order to better understand the importance of accurately modeling the high energy tail for SPE spectra, the contribution to astronaut whole body e ective dose equivalent of the high energy portions of three di erent SPE models has been evaluated. To ensure completeness of this analysis, simple and complex geometries were used. This analysis showed that the high energy tail of certain SPEs can be relevant to astronaut exposure and hence safety. Therefore, models of high energy tails for SPEs should be well analyzed and based on data if possible.

  15. A simple protocol for protein extraction of recalcitrant fruit tissues suitable for 2-DE and MS analysis.

    PubMed

    Song, Jun; Braun, Gordon; Bevis, Eric; Doncaster, Kristen

    2006-08-01

    Fruit tissues are considered recalcitrant plant tissue for proteomic analysis. Three phenol-free protein extraction procedures for 2-DE were compared and evaluated on apple fruit proteins. Incorporation of hot SDS buffer, extraction with TCA/acetone precipitation was found to be the most effective protocol. The results from SDS-PAGE and 2-DE analysis showed high quality proteins. More than 500 apple polypeptides were separated on a small scale 2-DE gel. The successful protocol was further tested on banana fruit, in which 504 and 386 proteins were detected in peel and flesh tissues, respectively. To demonstrate the quality of the extracted proteins, several protein spots from apple and banana peels were cut from 2-DE gels, analyzed by MS and have been tentatively identified. The protocol described in this study is a simple procedure which could be routinely used in proteomic studies of many types of recalcitrant fruit tissues.

  16. Theoretical and experimental spectroscopic analysis of cyano-substituted styrylpyridine compounds.

    PubMed

    Castro, Maria Eugenia; Percino, Maria Judith; Chapela, Victor M; Ceron, Margarita; Soriano-Moro, Guillermo; Lopez-Cruz, Jorge; Melendez, Francisco J

    2013-02-18

    A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)]pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and 1H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl- substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. 1H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and 1H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds.

  17. Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds

    PubMed Central

    Castro, Maria Eugenia; Percino, Maria Judith; Chapela, Victor M.; Ceron, Margarita; Soriano-Moro, Guillermo; Lopez-Cruz, Jorge; Melendez, Francisco J.

    2013-01-01

    A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)] pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and 1H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl-substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. 1H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and 1H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds. PMID:23429190

  18. Methods for Maximizing the Learning Process: A Theoretical and Experimental Analysis.

    ERIC Educational Resources Information Center

    Atkinson, Richard C.

    This research deals with optimizing the instructional process. The approach adopted was to limit consideration to simple learning tasks for which adequate mathematical models could be developed. Optimal or suitable suboptimal instructional strategies were developed for the models. The basic idea was to solve for strategies that either maximize the…

  19. Cost-effectiveness analysis of rotavirus vaccination among Libyan children using a simple economic model

    PubMed Central

    Alkoshi, Salem; Maimaiti, Namaitijiang; Dahlui, Maznah

    2014-01-01

    Background Rotavirus infection is a major cause of childhood diarrhea in Libya. The objective of this study is to evaluate the cost-effectiveness of rotavirus vaccination in that country. Methods We used a published decision tree model that has been adapted to the Libyan situation to analyze a birth cohort of 160,000 children. The evaluation of diarrhea events in three public hospitals helped to estimate the rotavirus burden. The economic analysis was done from two perspectives: health care provider and societal. Univariate sensitivity analyses were conducted to assess uncertainty in some values of the variables selected. Results The three hospitals received 545 diarrhea patients aged≤5 with 311 (57%) rotavirus positive test results during a 9-month period. The societal cost for treatment of a case of rotavirus diarrhea was estimated at US$ 661/event. The incremental cost-effectiveness ratio with a vaccine price of US$ 27 per course was US$ 8,972 per quality-adjusted life year gained from the health care perspective. From a societal perspective, the analysis shows cost savings of around US$ 16 per child. Conclusion The model shows that rotavirus vaccination could be economically a very attractive intervention in Libya. PMID:25499622

  20. Single-breath analysis using a novel simple sampler and capillary electrophoresis with contactless conductometric detection.

    PubMed

    Greguš, Michal; Foret, František; Kubáň, Petr

    2015-02-01

    The analysis of ionic content of exhaled breath condensate (EBC) from one single breath by CE with C(4) D is demonstrated for the first time. A miniature sampler made from a 2-mL syringe and an aluminum cooling cylinder for collection of EBC was developed. Various parameters of the sampler that influence its collection efficiency, repeatability, and effect of respiratory patterns were studied in detail. Efficient procedures for the cleanup of the miniature sampler were also developed and resulted in significant improvement of sampling repeatability. Analysis of EBC was performed by CE-C(4) D in a 60 mM MES/l-histidine BGE with 30 μM CTAB and 2 mM 18-crown-6 at pH 6 and excellent repeatability of migration times (RSD < 1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 12 inorganic anions, cations, and organic acids was obtained. It has been shown that the breathing pattern has a significant impact on the concentration of the analytes in the collected EBC. As the ventilatory pattern can be easily controlled during single exhalation, the developed collection system and method provides a highly reproducible and fast way of collecting EBC with applicability in point-of-care diagnostics.

  1. Theoretical analysis of the S{sub 2}←S{sub 0} vibronic spectrum of the 2-pyridone dimer

    SciTech Connect

    Kopec, Sabine; Köppel, Horst

    2016-01-14

    The interplay between excitonic and vibronic coupling in hydrogen-bonded molecular dimers leads to complex spectral structures and other intriguing phenomena such as a quenching of the excitonic energy splitting. We recently extended our analysis from that of the quenching mechanism to the theoretical investigation of the complete vibronic spectrum for the ortho-cyanophenol dimer. We now apply the same approach to the vibronic spectrum of the 2-pyridone dimer and discuss the assignment of vibronic lines to gain insight into the underlying coupling mechanism. This is based on potential energy surfaces obtained at the RI-CC2/aug-cc-pVTZ level. They are used for the dynamical analysis in the framework of a multi-mode vibronic coupling approach. The theoretical results based on the quadratic vibronic coupling model are found to be in good agreement with the experimental resonant two-photon ionization spectrum.

  2. Theoretical analysis of the S2←S0 vibronic spectrum of the 2-pyridone dimer.

    PubMed

    Kopec, Sabine; Köppel, Horst

    2016-01-14

    The interplay between excitonic and vibronic coupling in hydrogen-bonded molecular dimers leads to complex spectral structures and other intriguing phenomena such as a quenching of the excitonic energy splitting. We recently extended our analysis from that of the quenching mechanism to the theoretical investigation of the complete vibronic spectrum for the ortho-cyanophenol dimer. We now apply the same approach to the vibronic spectrum of the 2-pyridone dimer and discuss the assignment of vibronic lines to gain insight into the underlying coupling mechanism. This is based on potential energy surfaces obtained at the RI-CC2/aug-cc-pVTZ level. They are used for the dynamical analysis in the framework of a multi-mode vibronic coupling approach. The theoretical results based on the quadratic vibronic coupling model are found to be in good agreement with the experimental resonant two-photon ionization spectrum.

  3. Comparative forensic soil analysis of New Jersey state parks using a combination of simple techniques with multivariate statistics.

    PubMed

    Bonetti, Jennifer; Quarino, Lawrence

    2014-05-01

    This study has shown that the combination of simple techniques with the use of multivariate statistics offers the potential for the comparative analysis of soil samples. Five samples were obtained from each of twelve state parks across New Jersey in both the summer and fall seasons. Each sample was examined using particle-size distribution, pH analysis in both water and 1 M CaCl2 , and a loss on ignition technique. Data from each of the techniques were combined, and principal component analysis (PCA) and canonical discriminant analysis (CDA) were used for multivariate data transformation. Samples from different locations could be visually differentiated from one another using these multivariate plots. Hold-one-out cross-validation analysis showed error rates as low as 3.33%. Ten blind study samples were analyzed resulting in no misclassifications using Mahalanobis distance calculations and visual examinations of multivariate plots. Seasonal variation was minimal between corresponding samples, suggesting potential success in forensic applications.

  4. Theoretical sensitivity analysis of quadruple Vernier racetrack resonators designed for fabrication on the silicon-on-insulator platform

    NASA Astrophysics Data System (ADS)

    Boeck, Robert; Chrostowski, Lukas; Jaeger, Nicolas A. F.

    2014-09-01

    Vernier racetrack resonators offer advantages over single racetrack resonators such as extending the free spectral range (FSR).1-3 Here, we have presented a theoretical sensitivity analysis on quadruple Vernier racetrack resonators based on varying, one at a time, various fabrication dependent parameters. These parameters include the waveguide widths, heights, and propagation losses. We have shown that it should be possible to design a device that meets typical commercial specifications while being tolerant to changes in these parameters.

  5. The Dictyostelium Kinome—Analysis of the Protein Kinases from a Simple Model Organism

    PubMed Central

    Liu, Allen; Fey, Petra; Pilcher, Karen E; Xu, Yanji; Smith, Janet L

    2006-01-01

    Dictyostelium discoideum is a widely studied model organism with both unicellular and multicellular forms in its developmental cycle. The Dictyostelium genome encodes 285 predicted protein kinases, similar to the count of the much more advanced Drosophila. It contains members of most kinase classes shared by fungi and metazoans, as well as many previously thought to be metazoan specific, indicating that they have been secondarily lost from the fungal lineage. This includes the entire tyrosine kinase–like (TKL) group, which is expanded in Dictyostelium and includes several novel receptor kinases. Dictyostelium lacks tyrosine kinase group kinases, and most tyrosine phosphorylation appears to be mediated by TKL kinases. About half of Dictyostelium kinases occur in subfamilies not present in yeast or metazoa, suggesting that protein kinases have played key roles in the adaptation of Dictyostelium to its habitat. This study offers insights into kinase evolution and provides a focus for signaling analysis in this system. PMID:16596165

  6. Simple model analysis on the negative-ion extraction from a plasma

    SciTech Connect

    Lishev, St.; Shivarova, A.; Tarnev, Kh.

    2009-12-01

    Extraction of negative hydrogen ions from a plasma is analyzed with a view to the description of the extraction region of the negative hydrogen ion-beam sources developed for additional heating of fusion plasmas. The numerical procedure introduced in the study is a modification of the indirect Poisson-Vlasov method. It uses a condition for the plasma meniscus and employs analogy with the particle-in-cell model simulation. The analysis of the results shows that the charged particle velocity distribution at the entrance of the extraction region influences the properties of the extracted beams and its effect should be considered when conditions for well converged beams are looked for through variation in the plasma density and in the potentials of the electrodes of the extraction system.

  7. Simple, Reagentless Quantification of Total Bilirubin in Blood Via Microfluidic Phototreatment and Image Analysis.

    PubMed

    Thompson, Brandon L; Wyckoff, Sarah L; Haverstick, Doris M; Landers, James P

    2017-03-07

    Total bilirubin (T-Bil) is an important clinical diagnostic marker that is measured frequently by physicians to assist in the diagnosis, treatment, and monitoring of multiple medical conditions. The work demonstrated here utilizes the 48-year-old mechanism of phototherapy that is commonly implemented in the treatment of infants with exaggerated physiologic and pathologic jaundice but adapts it to the microfluidic level for the ultimate purpose of total bilirubin quantitation. After acquisition of a small volume of blood (<10 μL) and through subsequent separation (plasma + red blood cells), a 3 μL plasma sample was imaged by a portable scanner and analyzed through a custom algorithm for color intensity. After blue light irradiation for 10 min at 470 nm, the sample was reimaged and analyzed. The resulting intensities obtained pre- and postimaging (clearly observed through a color change from yellow to clear) were then utilized to calculate the total bilirubin concentration. A total of 34 blood samples were analyzed with microfluidic photo treatment-image analysis (μPIA) and were found to have a Deming-regression slope of 0.97 (R(2) = 0.960) when compared to the total bilirubin values determined in the clinical laboratory. We demonstrate the implementation of a centrifugal microdevice fabricated through the Print, Cut, and Laminate (PCL) method that accepts eight whole blood samples and provides the capabilities to not only quantitate total bilirubin (Deming-regression slope of 0.95, R(2) = 0.990) but allow future integration with excess plasma sufficient for additional downstream clinical assays. This work will highlight the inexpensive nature of the analysis (absence of caustic, viscous, or additional reagents), the simplicity (does not require any chemical reactions), speed (sample-to-answer in <15 min), insusceptibility to biofouling (no protein matrix effects, hemoglobin interferences, and minimized turbidity), low volume plasma requirement (3 μL), and the

  8. Portfolio theory and the alternative decision rule of cost-effectiveness analysis: theoretical and practical considerations.

    PubMed

    Sendi, Pedram; Al, Maiwenn J; Gafni, Amiram; Birch, Stephen

    2004-05-01

    Bridges and Terris (Soc. Sci. Med. (2004)) critique our paper on the alternative decision rule of economic evaluation in the presence of uncertainty and constrained resources within the context of a portfolio of health care programs (Sendi et al. Soc. Sci. Med. 57 (2003) 2207). They argue that by not adopting a formal portfolio theory approach we overlook the optimal solution. We show that these arguments stem from a fundamental misunderstanding of the alternative decision rule of economic evaluation. In particular, the portfolio theory approach advocated by Bridges and Terris is based on the same theoretical assumptions that the alternative decision rule set out to relax. Moreover, Bridges and Terris acknowledge that the proposed portfolio theory approach may not identify the optimal solution to resource allocation problems. Hence, it provides neither theoretical nor practical improvements to the proposed alternative decision rule.

  9. Theoretical development and first-principles analysis of strongly correlated systems

    NASA Astrophysics Data System (ADS)

    Liu, Chen

    A variety of quantum many-body methods have been developed for studying the strongly correlated electron systems. We have also proposed a computationally efficient and accurate approach, named the correlation matrix renormalization (CMR) method to address the challenges. The theoretic development and benchmark tests of the CMR method are included in this thesis. Meanwhile, ground state total energy is the most important property of electronic calculations. We also investigated an alternative approach to calculate the total energy, and extended this method for magnetic anisotropy energy of ferromagnetic materials. In addition, another theoretical tool, dynamical mean-field theory on top of the density functional theory, has also been used in electronic structure calculations for an Iridium oxide to study the phase transition, which results from an interplay of the d electrons' internal degrees of freedom.

  10. Theoretical and Experimental Analysis of Moisture-Dependent Thermal Conductivity of Lightweight Ceramic Bricks

    NASA Astrophysics Data System (ADS)

    Pavlík, Zbyšek; Fiala, Lukáš; Jerman, Miloš; Vejmelková, Eva; Pavlíková, Milena; Keppert, Martin; Černý, Robert

    2014-10-01

    The moisture-dependent thermal conductivity of two types of lightweight ceramic brick body is analyzed using both theoretical and experimental approaches. The basic physical properties are determined at first. Then, an impulse method is applied for the thermal-conductivity measurement. Initially, the material samples are dried, after that, they are exposed to liquid water for specific time intervals, and finally the moisture content is allowed to homogenize within the whole volume. The thermal-conductivity measurement is performed for different moisture contents achieved in this way. In the theoretical part, the homogenization principles are used for the calculation of the moisture-dependent thermal conductivity, utilizing the distribution functions based on the pore-size distribution measurement. Finally, a comparison of the measured and calculated data is done, and the validity of the applied effective media treatment is assessed.

  11. Analysis of theoretical and real values of heat consumption in units of the apartment building

    NASA Astrophysics Data System (ADS)

    Pavloková, Petra; Richter, Aleš; Janša, Jan

    2016-06-01

    This article is focused on heat consumption in the apartment building and the factors affecting it. The apartment building has three entrances and four over ground floors and one underground floor. In the entire apartment building there are 24 flats, which they are identical (kitchen, bedroom, living room and bathroom). In flats on radiators were installed the ratio heat meters according to Act 318/2012 Coll. by the Metrology Act. The ratio heat meters are used for fair billing of the heat costs for all owners. Continuous monitoring of the actual heat consumption in the flats were collected data of the real heat consumption. The theoretical values of heat consumption were counted in software ENERGIE. The apartment building is divided into24 flats and the calculation was made for each of them. The theoretical and real heat consumption was compared.

  12. Influential and theoretical analysis of nano-defect in the stub resonator

    PubMed Central

    Xu, Hui; Li, Hongjian; Li, Boxun; He, Zhihui; Chen, Zhiquan; Zheng, Mingfei

    2016-01-01

    We investigate a classic optical effect based on plasmon induced transparency (PIT) in a metal-insulator-metal (MIM) bus waveguide coupled with a single defective cavity. With the coupled mode theory (CMT), a theoretical model, for the single defective cavity, is established to study spectral features in the plasmonic waveguide. We can achieve a required description for the phenomenon, and the theoretical results also agree well with the finite-difference time-domain (FDTD) method. Our researches show that the defect’s position and size play important roles in the PIT phenomenon. By adjusting the position and size of the defect, we can realize the PIT phenomenon well and get the required slow light effect. The proposed model and findings may provide guidance for fundamental research of the control of light in highly integrated optical circuits. PMID:27477218

  13. On the independence of visual awareness and metacognition: a signal detection theoretic analysis.

    PubMed

    Jachs, Barbara; Blanco, Manuel J; Grantham-Hill, Sarah; Soto, David

    2015-04-01

    Classically, visual awareness and metacognition are thought to be intimately linked, with our knowledge of the correctness of perceptual choices (henceforth metacognition) being dependent on the level of stimulus awareness. Here we used a signal detection theoretic approach involving a Gabor orientation discrimination task in conjunction with trial-by-trial ratings of perceptual awareness and response confidence in order to gauge estimates of type-1 (perceptual) orientation sensitivity and type-2 (metacognitive) sensitivity at different levels of stimulus awareness. Data from three experiments indicate that while the level of stimulus awareness had a profound impact on type-1 perceptual sensitivity, the awareness effect on type-2 metacognitive sensitivity was far lower by comparison. The present data pose a challenge for signal detection theoretic models in which both type-1 (perceptual) and type-2 (metacognitive) processes are assumed to operate on the same input. More broadly, the findings challenge the commonly held view that metacognition is tightly coupled to conscious states.

  14. A simple ergonomic measure reduces fluoroscopy time during ERCP: A multivariate analysis

    PubMed Central

    Jowhari, Fahd; Hopman, Wilma M.; Hookey, Lawrence

    2017-01-01

    Background and study aims Endoscopic retrograde cholangiopancreatgraphy (ERCP) carries a radiation risk to patients undergoing the procedure and the team performing it. Fluoroscopy time (FT) has been shown to have a linear relationship with radiation exposure during ERCP. Recent modifications to our ERCP suite design were felt to impact fluoroscopy time and ergonomics. This multivariate analysis was therefore undertaken to investigate these effects, and to identify and validate various clinical, procedural and ergonomic factors influencing the total fluoroscopy time during ERCP. This would better assist clinicians with predicting prolonged fluoroscopic durations and to undertake relevant precautions accordingly. Patients and methods A retrospective analysis of 299 ERCPs performed by 4 endoscopists over an 18-month period, at a single tertiary care center was conducted. All inpatients/outpatients (121 males, 178 females) undergoing ERCP for any clinical indication from January 2012 to June 2013 in the chosen ERCP suite were included in the study. Various predetermined clinical, procedural and ergonomic factors were obtained via chart review. Univariate analyses identified factors to be included in the multivariate regression model with FT as the dependent variable. Results Bringing the endoscopy and fluoroscopy screens next to each other was associated with a significantly lesser FT than when the screens were separated further (–1.4 min, P = 0.026). Other significant factors associated with a prolonged FT included having a prior ERCP (+ 1.4 min, P = 0.031), and more difficult procedures (+ 4.2 min for each level of difficulty, P < 0.001). ERCPs performed by high-volume endoscopists used lesser FT vs. low-volume endoscopists (–1.82, P = 0.015). Conclusions Our study has identified and validated various factors that affect the total fluoroscopy time during ERCP. This is the first study to show that decreasing the distance between

  15. A simple ergonomic measure reduces fluoroscopy time during ERCP: A multivariate analysis.

    PubMed

    Jowhari, Fahd; Hopman, Wilma M; Hookey, Lawrence

    2017-03-01

    Background and study aims Endoscopic retrograde cholangiopancreatgraphy (ERCP) carries a radiation risk to patients undergoing the procedure and the team performing it. Fluoroscopy time (FT) has been shown to have a linear relationship with radiation exposure during ERCP. Recent modifications to our ERCP suite design were felt to impact fluoroscopy time and ergonomics. This multivariate analysis was therefore undertaken to investigate these effects, and to identify and validate various clinical, procedural and ergonomic factors influencing the total fluoroscopy time during ERCP. This would better assist clinicians with predicting prolonged fluoroscopic durations and to undertake relevant precautions accordingly. Patients and methods A retrospective analysis of 299 ERCPs performed by 4 endoscopists over an 18-month period, at a single tertiary care center was conducted. All inpatients/outpatients (121 males, 178 females) undergoing ERCP for any clinical indication from January 2012 to June 2013 in the chosen ERCP suite were included in the study. Various predetermined clinical, procedural and ergonomic factors were obtained via chart review. Univariate analyses identified factors to be included in the multivariate regression model with FT as the dependent variable. Results Bringing the endoscopy and fluoroscopy screens next to each other was associated with a significantly lesser FT than when the screens were separated further (-1.4 min, P = 0.026). Other significant factors associated with a prolonged FT included having a prior ERCP (+ 1.4 min, P = 0.031), and more difficult procedures (+ 4.2 min for each level of difficulty, P < 0.001). ERCPs performed by high-volume endoscopists used lesser FT vs. low-volume endoscopists (-1.82, P = 0.015). Conclusions Our study has identified and validated various factors that affect the total fluoroscopy time during ERCP. This is the first study to show that decreasing the distance between the

  16. Rural-urban migration, informal sector and development policies: a theoretical analysis.

    PubMed

    Gupta, M R

    1993-06-01

    "A theoretical model of rural-urban migration has been developed with special reference to the informal sector. The wage rate and employment in the informal sector are determined endogenously. The paper shows the simultaneous existence of open unemployment and informal sector in the urban area in migration equilibrium. The effects of alternative subsidy policies on unemployment and welfare of the workers are studied." The model is intended primarily for use in analyzing trends and policies in developing countries.

  17. Segregation during directional melting and its implications on seeded crystal growth: A theoretical analysis

    NASA Technical Reports Server (NTRS)

    Bourret, E. D.; Favier, J. J.; Witt, A. F.

    1982-01-01

    Directional melting of binary systems, as encountered during seeding in melt growth, is analyzed for concurrent compositional changes at the crystal-melt interface. It is shown that steady state conditions cannot normally be reached during seeding and that the growth interface temperature at the initial stages of seeded growth is a function of backmelt conditions. The theoretical treatment is numerically applied to Hg1-xCdXTe and Ga-doped Ge.

  18. Error control in the GCF: An information-theoretic model for error analysis and coding

    NASA Technical Reports Server (NTRS)

    Adeyemi, O.

    1974-01-01

    The structure of data-transmission errors within the Ground Communications Facility is analyzed in order to provide error control (both forward error correction and feedback retransmission) for improved communication. Emphasis is placed on constructing a theoretical model of errors and obtaining from it all the relevant statistics for error control. No specific coding strategy is analyzed, but references to the significance of certain error pattern distributions, as predicted by the model, to error correction are made.

  19. A theoretical model and analysis of composite membrane of a piezoresistive pressure sensor

    NASA Astrophysics Data System (ADS)

    Nie, Meng; Bao, Hong-Quan

    2016-10-01

    In this paper, an analytical model of the composite membrane piezoresistive pressure sensor with the testing structure is established, which built the relationship between the electrostatic force and the material properties, dimension parameters of the sensor. By using the theoretical model of the sensor, it is easily to analyze the sensor's performance, to optimize the dimension of the sensor, and to make the step of calibrating to be getting fast and accurate.

  20. Theoretical analysis of diffraction characteristics for peristrophic multiplexing with spherical reference wave

    NASA Astrophysics Data System (ADS)

    Yoshida, Shuhei; Mori, Jun; Yamamoto, Manabu

    2015-05-01

    Many kinds of recording techniques have been proposed for holographic data storages (HDS). Multiplexing recording technique is a primary contributor to determining the recording density in HDS. The method that utilizes spherical reference waves is characterized by the ability to enable multiplexing recording only by displacing (shifting or rotating) the recording medium. In this study, we propose a theoretical diffraction model of peristrophic multiplexing with spherical reference wave for HDS.

  1. Theoretical background of optical emission spectroscopy for analysis of atmospheric pressure plasmas

    NASA Astrophysics Data System (ADS)

    Belmonte, Thierry; Noël, Cédric; Gries, Thomas; Martin, Julien; Henrion, Gérard

    2015-12-01

    This review contains a theoretical background of optical emission spectroscopy and some selected examples of issues in the field of atmospheric plasmas. It includes elements like line broadening, emission of continua and molecules, radiation models, etc. Modernized expressions figuring the terms hidden in global constants where cgs units prevail are given together with restrictions of use. Easy-to-use formulas are provided to give access to essential plasma parameters.

  2. A Theoretical Analysis of a New Polarimetric Optical Scheme for Glucose Sensing in the Human Eye

    NASA Technical Reports Server (NTRS)

    Rovati, Luigi L.; Boeckle, Stefan; Ansari, Rafat R.; Salzman, Jack A. (Technical Monitor)

    2002-01-01

    The challenging task of in vivo polarimetric glucose sensing is the identification and selection of a scheme to optically access the aqueous humor of the human eye. In this short communication an earlier approach of Cote et al. is theoretically compared with our new optical scheme. Simulations of the new scheme using the eye model of Navarro, suggest that the new optical geometry can overcome the limitations of the previous approach for in vivo measurements of glucose in a human eye.

  3. A Simple Geotracer Compositional Correlation Analysis Reveals Oil Charge and Migration Pathways

    PubMed Central

    Yang, Yunlai; Arouri, Khaled

    2016-01-01

    A novel approach, based on geotracer compositional correlation analysis is reported, which reveals the oil charge sequence and migration pathways for five oil fields in Saudi Arabia. The geotracers utilised are carbazoles, a family of neutral pyrrolic nitrogen compounds known to occur naturally in crude oils. The approach is based on the concept that closely related fields, with respect to filling sequence, will show a higher carbazole compositional correlation, than those fields that are less related. That is, carbazole compositional correlation coefficients can quantify the charge and filling relationships among different fields. Consequently, oil migration pathways can be defined based on the established filling relationships. The compositional correlation coefficients of isomers of C1 and C2 carbazoles, and benzo[a]carbazole for all different combination pairs of the five fields were found to vary extremely widely (0.28 to 0.94). A wide range of compositional correlation coefficients allows adequate differentiation of separate filling relationships. Based on the established filling relationships, three distinct migration pathways were inferred, with each apparently being charged from a different part of a common source kitchen. The recognition of these charge and migration pathways will greatly aid the search for new accumulations. PMID:26965479

  4. A Simple Geotracer Compositional Correlation Analysis Reveals Oil Charge and Migration Pathways

    NASA Astrophysics Data System (ADS)

    Yang, Yunlai; Arouri, Khaled

    2016-03-01

    A novel approach, based on geotracer compositional correlation analysis is reported, which reveals the oil charge sequence and migration pathways for five oil fields in Saudi Arabia. The geotracers utilised are carbazoles, a family of neutral pyrrolic nitrogen compounds known to occur naturally in crude oils. The approach is based on the concept that closely related fields, with respect to filling sequence, will show a higher carbazole compositional correlation, than those fields that are less related. That is, carbazole compositional correlation coefficients can quantify the charge and filling relationships among different fields. Consequently, oil migration pathways can be defined based on the established filling relationships. The compositional correlation coefficients of isomers of C1 and C2 carbazoles, and benzo[a]carbazole for all different combination pairs of the five fields were found to vary extremely widely (0.28 to 0.94). A wide range of compositional correlation coefficients allows adequate differentiation of separate filling relationships. Based on the established filling relationships, three distinct migration pathways were inferred, with each apparently being charged from a different part of a common source kitchen. The recognition of these charge and migration pathways will greatly aid the search for new accumulations.

  5. Infrared spectrum analysis of the dissociated states of simple amino acids.

    PubMed

    Sebben, Damien; Pendleton, Phillip

    2014-11-11

    In this work, we present detailed analyses of the dissociation of dilute aqueous solutions of glycine and of lysine over the range 1Analysis of the deconvoluted peak areas due to CO and COO- at pH ranges<4.5 and those due to NH2 and NH3+ for pH>8 resulted in consistent pKa values for the amino acids.

  6. Computationally Simple Analysis of Matched, Outcome-Based Studies of Ordinal Disease States

    PubMed Central

    Betensky, Rebecca A.; Szymonifka, Jackie; Lee, Eudocia Q.; Nutt, Catherine L.; Batchelor, Tracy T.

    2015-01-01

    Outcome-based sampling is an efficient study design for rare conditions, such as glioblastoma. It is often used in conjunction with matching, for increased efficiency and to potentially avoid bias due to confounding. A study was conducted at Massachusetts General Hospital (MGH) that involved retrospective sampling of glioblastoma patients with respect to multiple ordered disease states, as defined by three categories of overall survival time. To analyze such studies, we posit an adjacent categories logit model and exploit its allowance for prospective analysis of a retrospectively sampled study and its advantageous removal of set and level specific nuisance parameters through conditioning on sufficient statistics. This framework allows for any sampling design and is not limited to one level of disease within each set, as is the development of Mukherjee et al. [1]. We describe how this ordinal conditional model can be fit using standard conditional logistic regression procedures. We consider an alternative pseudo-likelihood approach that potentially offers robustness under partial model misspecification at the expense of slight loss of efficiency under correct model specification for small sample sizes. We apply our methods to the MGH glioblastoma study. PMID:25900819

  7. Theoretical Analysis of the Mechanism of Fracture Network Propagation with Stimulated Reservoir Volume (SRV) Fracturing in Tight Oil Reservoirs

    PubMed Central

    Su, Yuliang; Ren, Long; Meng, Fankun; Xu, Chen; Wang, Wendong

    2015-01-01

    Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and propagation criteria for the theoretical model of fracture network propagation and its derivation. A reasonable solution of the theoretical model for a tight oil reservoir is obtained and verified by a numerical discrete method. Through theoretical calculation and computer programming, the variation rules of formation stress fields, hydraulic fracture propagation patterns (FPP) and branch fracture propagation angles and pressures are analyzed. The results show that during the process of fracture propagation, the initial orientation of the principal stress deflects, and the stress fields at the fracture tips change dramatically in the region surrounding the fracture. Whether the ideal fracture network can be produced depends on the geological conditions and on the engineering treatments. This study has both theoretical significance and practical application value by contributing to a better understanding of fracture network propagation mechanisms in unconventional oil/gas reservoirs and to the improvement of the science and design efficiency of reservoir fracturing. PMID:25966285

  8. Theoretical Analysis of the Mechanism of Fracture Network Propagation with Stimulated Reservoir Volume (SRV) Fracturing in Tight Oil Reservoirs.

    PubMed

    Su, Yuliang; Ren, Long; Meng, Fankun; Xu, Chen; Wang, Wendong

    2015-01-01

    Stimulated reservoir volume (SRV) fracturing in tight oil reservoirs often induces complex fracture-network growth, which has a fundamentally different formation mechanism from traditional planar bi-winged fracturing. To reveal the mechanism of fracture network propagation, this paper employs a modified displacement discontinuity method (DDM), mechanical mechanism analysis and initiation and propagation criteria for the theoretical model of fracture network propagation and its derivation. A reasonable solution of the theoretical model for a tight oil reservoir is obtained and verified by a numerical discrete method. Through theoretical calculation and computer programming, the variation rules of formation stress fields, hydraulic fracture propagation patterns (FPP) and branch fracture propagation angles and pressures are analyzed. The results show that during the process of fracture propagation, the initial orientation of the principal stress deflects, and the stress fields at the fracture tips change dramatically in the region surrounding the fracture. Whether the ideal fracture network can be produced depends on the geological conditions and on the engineering treatments. This study has both theoretical significance and practical application value by contributing to a better understanding of fracture network propagation mechanisms in unconventional oil/gas reservoirs and to the improvement of the science and design efficiency of reservoir fracturing.

  9. Theoretical modeling and experimental analysis of solar still integrated with evacuated tubes

    NASA Astrophysics Data System (ADS)

    Panchal, Hitesh; Awasthi, Anuradha

    2016-12-01

    In this present research work, theoretical modeling of single slope, single basin solar still integrated with evacuated tubes has been performed based on energy balance equations. Major variables like water temperature, inner glass cover temperature and distillate output has been computed based on theoretical modeling. The experimental setup has been made from locally available materials and installed at Gujarat Power Engineering and Research Institute, Mehsana, Gujarat, India (23.5880°N, 72.3693°E) with 0.04 m depth during 6 months of time interval. From the series of experiments, it is found considerable increment in average distillate output of a solar still when integrated with evacuated tubes not only during daytime but also from night time. In all experimental cases, the correlation of coefficient (r) and root mean square percentage deviation of theoretical modeling and experimental study found good agreement with 0.97 < r < 0.98 and 10.22 < e < 38.4% respectively.

  10. Fabrication, characterization, and theoretical analysis of controlled disorder in the core of optical fibers.

    PubMed

    Puente, Norma P; Chaikina, Elena I; Herath, Sumudu; Yamilov, Alexey

    2011-02-20

    We present results of experimental and theoretical studies of polarization-resolved light transmission through optical fiber with disorder generated in its germanium-doped core via UV radiation transmitted through a diffuser. In samples longer than a certain characteristic length, the power transmitted with preserved polarization is observed to be distributed over all forward-propagating modes, as evidenced by the Rayleigh negative exponential distribution of the near-field intensity at the output surface of the fiber. Furthermore, the transmitted power becomes also equally distributed over both polarizations. To describe the optical properties of the fibers with the experimentally induced disorder, a theoretical model based on coupled-mode theory is developed. The obtained analytical expression for the correlation function describing spatial properties of the disorder shows that it is highly anisotropic. Our calculations demonstrate that this experimentally controllable anisotropy can lead to suppression of the radiative leakage of the propagating modes, so that intermode coupling becomes the dominant scattering process. The obtained theoretical expressions for the polarization-resolved transmission fit very well with the experimental data, and the information extracted from the fit shows that radiative leakage is indeed small. The reported technique provides an easy way to fabricate different configurations of controlled disorder in optical fibers suitable for such applications as random fiber lasers.

  11. Theoretical analysis of copper-ion extraction through hollow fiber supported liquid membranes

    SciTech Connect

    Shiau, C.Y.; Chen, P.Z. )

    1993-10-01

    An understanding of the extraction of metal ions through hollow fiber supported liquid membranes is important for the design of such systems. In this paper, copper-ion extraction through hollow fiber supported liquid membranes containing D2EHPA as a carrier agent is analyzed. Both a rigorous model and a simple model with varied permeation coefficients for the system are proposed. The once-through mode is first modeled and the parametric effects on the extraction rate are discussed. The recycling mode is then modeled. A comparison between the rigorous model and the simple model with varied/constant permeation coefficients is made. From the models it is found that the permeation coefficient is a function of copper ion concentration. 18 refs., 9 figs., 1 tab.

  12. Simple Saucers

    ERIC Educational Resources Information Center

    Coy, Mary

    2008-01-01

    With standardized English Language Arts exams on the horizon, the author thought a game of Antonyms would provide not only a quick language arts activity for her sixth graders, but also a nice segue to an art lesson in contrast. In this article, she describes a project, a simple saucer on a pedestal base, which required students to demonstrate…

  13. Information-theoretic analysis of x-ray photoabsorption based threat detection system for check-point

    NASA Astrophysics Data System (ADS)

    Lin, Yuzhang; Allouche, Genevieve G.; Huang, James; Ashok, Amit; Gong, Qian; Coccarelli, David; Stoian, Razvan-Ionut; Gehm, Michael E.

    2016-05-01

    In this work we present an information-theoretic framework for a systematic study of checkpoint x-ray systems using photoabsorption measurements. Conventional system performance analysis of threat detection systems confounds the effect of the system architecture choice with the performance of a threat detection algorithm. However, our system analysis approach enables a direct comparison of the fundamental performance limits of disparate hardware architectures, independent of the choice of a specific detection algorithm. We compare photoabsorptive measurements from different system architectures to understand the affect of system geometry (angular views) and spectral resolution on the fundamental limits of the system performance.

  14. SYMPHONY, an information-theoretic method for gene–gene and gene–environment interaction analysis of disease syndromes

    PubMed Central

    Knights, J; Yang, J; Chanda, P; Zhang, A; Ramanathan, M

    2013-01-01

    We develop an information-theoretic method for gene–gene (GGI) and gene–environmental interactions (GEI) analysis of syndromes, defined as a phenotype vector comprising multiple quantitative traits (QTs). The K-way interaction information (KWII), an information-theoretic metric, was derived for multivariate normal distributed phenotype vectors. The utility of the method was challenged with three simulated data sets, the Genetic Association Workshop-15 (GAW15) rheumatoid arthritis data set, a high-density lipoprotein (HDL) and atherosclerosis data set from a mouse QT locus study, and the 1000 Genomes data. The dependence of the KWII on effect size, minor allele frequency, linkage disequilibrium, population stratification/admixture, as well as the power and computational time requirements of the novel method was systematically assessed in simulation studies. In these studies, phenotype vectors containing two and three constituent multivariate normally distributed QTs were used and the KWII was found to be effective at detecting GEI associated with the phenotype. High KWII values were observed for variables and variable combinations associated with the syndrome phenotype compared with uninformative variables not associated with the phenotype. The KWII values for the phenotype-associated combinations increased monotonically with increasing effect size values. The KWII also exhibited utility in simulations with non-linear dependence between the constituent QTs. Analysis of the HDL and atherosclerosis data set indicated that the simultaneous analysis of both phenotypes identified interactions not detected in the analysis of the individual traits. The information-theoretic approach may be useful for non-parametric analysis of GGI and GEI of complex syndromes. PMID:23423149

  15. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    NASA Astrophysics Data System (ADS)

    Pan, B.; Wang, B.; Lubineau, G.

    2016-07-01

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work.

  16. Protocol: A simple protocol for quantitative analysis of bio-oils through gas- chromatography/mass spectrometry.

    PubMed

    Bartoli, Mattia; Rosi, Luca; Frediani, Marco; Frediani, Piero

    2016-01-01

    A new and simple protocol for quantitative analysis of bio-oils using gas-chromatography/mass spectrometry is suggested. Compounds were identified via their mass spectra, and then unavailable response factors were calculated with respect to diphenyl as the internal standard using a modified method previously suggested for gas chromatography with flame ionization detection. This new protocol was applied to the characterization of bio-oils obtained from the pyrolysis of woods of different sources or using different pyrolysis procedures. This protocol allowed evaluation of the yields of products from poplar pyrolysis (among 50% and 99%), while a reduced amounts of products were identified from the pyrolysis of cellulose (between 46% and 58%). The main product was always acetic acid, but it was formed in very large yields from poplar while lower yields were obtained from cellulose.

  17. Proposal of a simple and effective local reactivity descriptor through a topological analysis of an orbital-weighted fukui function.

    PubMed

    Pino-Rios, Ricardo; Yañez, Osvaldo; Inostroza, Diego; Ruiz, Lina; Cardenas, Carlos; Fuentealba, Patricio; Tiznado, William

    2017-03-30

    The prediction of reactivity is one of the long-standing objectives of chemistry, contributing to enforce the link between theory and experiment. In particular, the regioselectivity of aromatic molecules has motivated the proposal of different reactivity descriptors based on foundational theories, like Frontier Molecular Orbital (FMO) theory and density functional theory, to predict and rationalize such regioselectivity. This article examines cases where reactivity descriptors, based on FMO theories, are known to have failed, specifically on electrophilic aromatic substitution reactions, through a simple but effective new reactivity model: the Orbital-weighted Fukui function ( fw-(r)) and its topological analysis. Interestingly, this descriptor proves to be effective in adequately predicting regioselectivities where other approximations failed. © 2017 Wiley Periodicals, Inc.

  18. Rapid, simple method of preparing rotaviral double-stranded ribonucleic acid for analysis by polyacrylamide gel electrophoresis.

    PubMed Central

    Theil, K W; McCloskey, C M; Saif, L J; Redman, D R; Bohl, E H; Hancock, D D; Kohler, E M; Moorhead, P D

    1981-01-01

    A procedure for extracting rotaviral double-stranded ribonucleic acid (RNA) directly from fecal and intestinal specimens collected from calves and pigs is described. This procedure provides a rapid, simple, reproducible method of obtaining rotaviral double-stranded RNA preparations suitable for electrophoretic analysis in polyacrylamide-agarose composite gels. The rotaviral genome electrophoretic migration pattern produced by double-stranded RNA extracted directly from a specimen by this procedure was qualitatively identical to the electrophoretic migration pattern obtained with double-stranded RNA extracted from purified rotavirus derived from the same specimen. Direct extraction of specimens containing porcine rotavirus-like virus by this procedure gave preparations that had electrophoretic migration patterns similar, but not identical, to the characteristic electrophoretic migration pattern of the rotaviral genome. Sufficient rotaviral double-stranded RNA could be extracted from 6 ml of fecal or intestinal specimen by this procedure to permit 15 or more electrophoretic assays. Images PMID:6270190

  19. Experimental and theoretical performance analysis for a CMOS-based high resolution image detector

    PubMed Central

    Jain, Amit; Bednarek, Daniel R.; Rudin, Stephen

    2014-01-01

    Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present state-of-the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 µm pixels and an active area of 12 cm × 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/µR and 0.55 µR in high sensitivity mode, while they were 9.87 DN/µR and 2.77 µR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors. PMID:25300571

  20. Experimental and theoretical performance analysis for a CMOS-based high resolution image detector

    NASA Astrophysics Data System (ADS)

    Jain, Amit; Bednarek, Daniel R.; Rudin, Stephen

    2014-03-01

    Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present stateof- the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 μm pixels and an active area of 12 cm x 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/μR and 0.55 μR in high sensitivity mode, while they were 9.87 DN/μR and 2.77 μR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors.

  1. Experimental and theoretical performance analysis for a CMOS-based high resolution image detector.

    PubMed

    Jain, Amit; Bednarek, Daniel R; Rudin, Stephen

    2014-03-19

    Increasing complexity of endovascular interventional procedures requires superior x-ray imaging quality. Present state-of-the-art x-ray imaging detectors may not be adequate due to their inherent noise and resolution limitations. With recent developments, CMOS based detectors are presenting an option to fulfill the need for better image quality. For this work, a new CMOS detector has been analyzed experimentally and theoretically in terms of sensitivity, MTF and DQE. The detector (Dexela Model 1207, Perkin-Elmer Co., London, UK) features 14-bit image acquisition, a CsI phosphor, 75 µm pixels and an active area of 12 cm × 7 cm with over 30 fps frame rate. This detector has two modes of operations with two different full-well capacities: high and low sensitivity. The sensitivity and instrumentation noise equivalent exposure (INEE) were calculated for both modes. The detector modulation-transfer function (MTF), noise-power spectra (NPS) and detective quantum efficiency (DQE) were measured using an RQA5 spectrum. For the theoretical performance evaluation, a linear cascade model with an added aliasing stage was used. The detector showed excellent linearity in both modes. The sensitivity and the INEE of the detector were found to be 31.55 DN/µR and 0.55 µR in high sensitivity mode, while they were 9.87 DN/µR and 2.77 µR in low sensitivity mode. The theoretical and experimental values for the MTF and DQE showed close agreement with good DQE even at fluoroscopic exposure levels. In summary, the Dexela detector's imaging performance in terms of sensitivity, linear system metrics, and INEE demonstrates that it can overcome the noise and resolution limitations of present state-of-the-art x-ray detectors.

  2. A theoretical method for the analysis and design of axisymmetric bodies. [flow distribution and incompressible fluids

    NASA Technical Reports Server (NTRS)

    Beatty, T. D.

    1975-01-01

    A theoretical method is presented for the computation of the flow field about an axisymmetric body operating in a viscous, incompressible fluid. A potential flow method was used to determine the inviscid flow field and to yield the boundary conditions for the boundary layer solutions. Boundary layer effects in the forces of displacement thickness and empirically modeled separation streamlines are accounted for in subsequent potential flow solutions. This procedure is repeated until the solutions converge. An empirical method was used to determine base drag allowing configuration drag to be computed.

  3. Information-theoretical analysis of topological entanglement entropy and multipartite correlations

    NASA Astrophysics Data System (ADS)

    Kato, Kohtaro; Furrer, Fabian; Murao, Mio

    2016-02-01

    A special feature of the ground state in a topologically ordered phase is the existence of large-scale correlations depending only on the topology of the regions. These correlations can be detected by the topological entanglement entropy or by a measure called irreducible correlation. We show that these two measures coincide for states obeying an area law and having zero correlation length. Moreover, we provide an operational meaning for these measures by proving its equivalence to the optimal rate of a particular class of secret sharing protocols. This establishes an information-theoretical approach to multipartite correlations in topologically ordered systems.

  4. Comparative study of experimental and theoretical analysis of EXAFS data of copper complexes using FT method

    NASA Astrophysics Data System (ADS)

    Mishra, A.; Mishra, S.; Kekre, P.; Choudhary, Pankaj

    2014-09-01

    The X-ray absorption spectra at the K-edge for a series of copper mixed ligand, having hydroxypyridine as one of the ligands, have been investigated in the laboratory X-ray spectroscopic set-up. In the series only X-ray absorption near edge structure (XANES) parameters and bond length using modified Lytle, Levy's and LSS methods were calculated. In the present study the bond lengths are calculated by Fourier Transform method theoretically using IFEFFIT software and compared with experimental results.

  5. Fat stigma and public health: a theoretical framework and ethical analysis.

    PubMed

    Abu-Odeh, Desiree

    2014-09-01

    This paper proposes a theoretical framework for understanding fat stigma and its impact on people's well-being. It argues that stigma should never be used as a tool to achieve public health ends. Drawing on Bruce Link and Jo Phelan's 2001 conceptualization of stigma as well as the works of Hilde Lindemann, Paul Benson, and Margaret Urban Walker on identity, positionality, and agency, this paper clarifies the mechanisms by which stigmatizing, oppressive conceptions of overweight and obesity damage identities and diminish moral agency, arguing that the use of obesity-related stigma for public health ends violates the bioethics principles of nonmaleficence, autonomy, and justice.

  6. Theoretical analysis of structural diversity of covalent organic framework: Stacking isomer structures thermodynamics and kinetics

    NASA Astrophysics Data System (ADS)

    Hayashi, Taku; Hijikata, Yuh; Page, Alister; Jiang, Donglin; Irle, Stephan

    2016-11-01

    Covalent organic frameworks (COFs) have attracted much interest due to their utility as functional materials. Unfortunately, experimental synthesis struggles with low single crystallinity of COFs. We have theoretically investigated isomer structures of a representative two-dimensional COF for both monolayer and three-dimensional stacking orders. We show that rotations of p-phenylene rings are common in monolayers, however, affect the global stacking order substantially. We also discuss the discrepancy between powder X-ray diffraction patterns corresponding to the structures predicted by our calculations and those experimentally observed. The discrepancy demonstrates the importance of dynamics in the self-assembly process of COF organic components.

  7. Theoretical and experimental analysis of double-pass ytterbium-doped fiber amplifier

    NASA Astrophysics Data System (ADS)

    Zhang, Pengfei; Su, Rongtao; Huang, Long; Du, Daiyan; Yang, Lijia

    2016-11-01

    We theoretically and experimentally demonstrate a double-pass ytterbium-doped fiber amplifier. First, we numerically analyze the impact of fiber length on the amplifier. In our experiment, a laser seed with output power of 100 μW and wavelength of 1064 nm is amplified to 51.2 mW with a signal gain of 27.1 dB. With this double-pass configuration, amplified spontaneous emission (ASE) is effectively suppressed to more than 30 dB. Compared with single pass configuration, it is found that double-pass amplification configuration enhances the gain coefficient and improves the signal-to-noise ratio.

  8. The theoretical analysis of the Fog removal in the LNG Ambient Vaporizer

    NASA Astrophysics Data System (ADS)

    Lee, T.; Lee, D.; Jeong, H.; Chung, H.

    2015-09-01

    The fog removal process is one of the important process in LNG Ambient Vaporizer. In this study we carried out theoretical study of the fog removal process in LNG Ambient Vaporizer. The LNG Ambient Vaporizer in Incheon area was used in our study. The fog temperature and the required energy produced from air fan to remove fog in LNG Ambient Vaporizer were calculated using average temperature of Incheon area in 2012 by Psychometruc Chart method. As a result we can be remove fog in LNG Ambient Vaporizer using Enthalpy[kW] energy in summer season and Enthalpy[kW] in winter season respectively.

  9. Polarimetric Glucose Sensing Using Brewster Reflection off of Eye Lens: Theoretical Analysis

    NASA Technical Reports Server (NTRS)

    Boeckle, Stefan; Rovati, Luigi; Ansari, Rafat R.

    2002-01-01

    An important task of in vivo polarimetric glucose sensing is to find an appropriate way to optically access the aqueous humor of the human eye. In this paper two different approaches are analyzed theoretically and applied to the eye model of Le Grand. First approach is the tangential path of Cote, et al. (G.L. Cot6, M.D. Fox, and R.B. Northrop: Noninvasive Optical Polarimetric Glucose Sensing Using a True Phase Measurement Technique. IEEE Transactions on Biomedical Engineering, vol. 39, no. 7, pp. 752-756, 1992.) and the second is a new scheme of this paper of applying Brewster reflection off the eye lens.

  10. Theoretical considerations for anticipating of function analysis on a gradient index-lens fabrication through double ion-exchange process.

    PubMed

    Zakeri, Banafsheh; Sabatyan, Arash

    2012-09-10

    Based on precise and detailed theoretical examination of diffusion equation analysis, two-step Ag(+)-Na(+) and Na(+)-Ag(+) ion-exchange parameters were optimized in order to fabricate a gradient index (GRIN) lens in the BK7 glass rod. Using the diffusion equation, the impact of the concentration ratio of the exchanged ion during the first and second steps was examined in detail. Then, based on the calculated effective parameters such as concentration ratio and immersion time, a fabrication process was proposed. We managed to get the optimum parameters (the bath stop time, temperature, and length) to make a quarter pitch lens. As a result, some samples of the GRIN lens were fabricated and tested successfully. Theoretical considerations and experimental results are presented.

  11. Theoretical analysis and simulation of obstructed breakup of micro-droplet in T-junction under an asymmetric pressure difference

    NASA Astrophysics Data System (ADS)

    Fu, Yuhang; Bai, Lin; Jin, Yong; Cheng, Yi

    2017-03-01

    Asymmetric droplet breakup under a pressure difference at two outlets of a T-junction is investigated theoretically and numerically in this study. An accurate analysis of the evolution of droplet dynamics during the obstructed breakup process has been conducted. Meanwhile, the lattice Boltzmann method based on color gradient model is employed to simulate the system with the verification of the theoretical results. It is demonstrated that the Zou-He boundary setting at each outlet is advantageous for modifying the pressure drop of the two branches of T-junction. The results reveal that asymmetric breakup of the unequally sized droplets follows two steps, namely, the filling stage and the breakup stage. Then a universal parameter is proposed to describe the asymmetric condition of droplet breakup in T-junction, which plays a key role to characterize the temporal evolution of volume ratio and the droplet length of formed smaller droplets.

  12. Theoretical geodesy

    NASA Astrophysics Data System (ADS)

    Borkowski, Andrzej; Kosek, Wiesław

    2015-12-01

    The paper presents a summary of research activities concerning theoretical geodesy performed in Poland in the period of 2011-2014. It contains the results of research on new methods of the parameter estimation, a study on robustness properties of the M-estimation, control network and deformation analysis, and geodetic time series analysis. The main achievements in the geodetic parameter estimation involve a new model of the M-estimation with probabilistic models of geodetic observations, a new Shift-Msplit estimation, which allows to estimate a vector of parameter differences and the Shift-Msplit(+) that is a generalisation of Shift-Msplit estimation if the design matrix A of a functional model has not a full column rank. The new algorithms of the coordinates conversion between the Cartesian and geodetic coordinates, both on the rotational and triaxial ellipsoid can be mentioned as a highlights of the research of the last four years. New parameter estimation models developed have been adopted and successfully applied to the control network and deformation analysis. New algorithms based on the wavelet, Fourier and Hilbert transforms were applied to find time-frequency characteristics of geodetic and geophysical time series as well as time-frequency relations between them. Statistical properties of these time series are also presented using different statistical tests as well as 2nd, 3rd and 4th moments about the mean. The new forecasts methods are presented which enable prediction of the considered time series in different frequency bands.

  13. Integrated seismic risk analysis using simple weighting method: the case of residential Eskişehir, Turkey

    NASA Astrophysics Data System (ADS)

    Pekkan, E.; Tun, M.; Guney, Y.; Mutlu, S.

    2015-06-01

    A large part of the residential areas in Turkey are at risk from earthquakes. The main factors that threaten residential areas during an earthquake are poor quality building stock and soil problems. Liquefaction, loss of bearing capacity, amplification, slope failure, and landslide hazards must be taken into account for residential areas that are close to fault zones and covered with younger sediments. Analyzing these hazards separately and then combining the analyses would ensure a more realistic risk evaluation according to population density than analyzing several risks based on a single parameter. In this study, an integrated seismic risk analysis of central Eskişehir was performed based on two earthquake related parameters, liquefaction and amplification. The analysis used a simple weighting method. Other earthquake-related problems such as loss of bearing capacity, landslides, and slope failures are not significant for Eskişehir because of the geological and the topographical conditions of the region. According to the integrated seismic risk analysis of the Eskişehir residential area, the populated area is found to be generally at medium to high risk during a potential earthquake.

  14. A theoretical and experimental analysis of polymerization shrinkage of bone cement: A potential major source of porosity.

    PubMed

    Gilbert, J L; Hasenwinkel, J M; Wixson, R L; Lautenschlager, E P

    2000-10-01

    A theoretical basis for understanding polymerization shrinkage of bone cement is presented based on density changes in converting monomer to polymer. Also, an experimental method, based on dilatometry and the Archimedes' principle is presented for highly precise and accurate measurement of unconstrained volumetric shrinkage of bone cement. Furthermore, a theoretical and experimental analysis of polymerization shrinkage in a constrained deformational state is presented to demonstrate that porosity can develop due to shrinkage. Six bone-cement conditions (Simplex-Ptrade mark vacuum and hand mixed, Endurancetrade mark vacuum mixed, and three two-solution experimental bone cements with higher initial monomer levels) were tested for volumetric shrinkage. It was found that shrinkage varied statistically (p< or = 0.05) from 5.1% (hand-mixed Simplex-Ptrade mark) to 6.7% (vacuum-mixed Simplex-Ptrade mark) to 10.5% for a 0.6:1 (polymer g/monomer mL) two-solution bone cement. Shrinkage was highly correlated with initial monomer content (R(2) = 0.912) but with a lower than theoretically expected rate. This discrepancy was due to the presence of residual monomer after polymerization. Using previously determined residual monomer levels, the theoretic shrinkage analysis was shown to be predictive of the shrinkage results with some residual monomer left after polymerization. Polymerization of a two-solution bone cement in a constrained state resulted in pores developing with volumes predicted by the theory that they are the result of shrinkage. The results of this study show that shrinkage of bone cement under certain constrained conditions may result in the development of porosity at the implant-bone cement interface and elsewhere in the polymerizing cement mantle.

  15. Sound propagation in woods. Comparative analysis between in situ measurements, laboratory measurements and the values predicted by a theoretical model

    NASA Astrophysics Data System (ADS)

    Tarrero Fernandez, Ana Isabel

    This PhD Thesis studies sound propagation outdoors and the potential effect of trees on such propagation. In the first part of the thesis, seven different types of grounds (sand, grass, concrete...) are characterised from an acoustical point of view. In order to determine the ground impedance of each type of ground, it was necessary to determine the flow resistivity by means of an indirect method. In this method the flow resistivity values are chosen so as to give the best fit between experimental values and the values given by a theoretical propagation model. This first part includes a comparative analysis of sound attenuation over two very similar types of grounds, one with trees and the other one without trees. It is observed that at high frequencies sound attenuation in the case of ground with trees (wood) is higher. In the second part of this work, the theoretical outdoor sound propagation model NORD 2000, which has been developed by a group of scientists in the Scandinavian countries, is described and then validated. This model takes into account the source characteristics, the geometric divergence, atmospheric absorption, ground effects and the scattering produced by obstacles such as trees, houses... In order to validate this theoretical model, we have compared the predictions given by the model under many different circumstances with the values measured in situ in different types of woods and also with the values measured in a scaled model in laboratory, using different trees density, trunk diameters... From a deep analysis of all the set of comparisons it was concluded that the theoretical model NORD 2000 agrees very well with the experimental values both measured in situ and in laboratory (scale model) at low and medium frequencies. At high frequencies there are some discrepancies between the model and the experimental values.

  16. A theoretical analysis of the reaction between ethyl and molecular oxygen

    SciTech Connect

    James A. Miller; Stephen J. Klippenstein; Stuart H. Robertson

    2000-12-13

    Using a combination of electronic-structure theory, variational transition-state theory, and solutions to the time-dependent master equation, the authors have studied the kinetics of the title reaction theoretically over wide ranges of temperature and pressure. The agreement between theory and experiment is quite good. By comparing the theoretical and experimental results describing the kinetic behavior, they have been able to deduce a value for the C{sub 2}H{sub 5}-O{sub 2} bond energy of {approximately}34 kcal/mole and a value for the exit-channel transition-state energy of {minus}4.3 kcal/mole (measured from reactants). These numbers compare favorably with the electronic-structure theory predictions of 33.9 kcal/mole and {minus}3.0 kcal/mole, respectively. The master-equation solutions show three distinct temperature regimes for the reaction, discussed extensively in the paper. Above T {approx} 700 K, the reaction can be written as an elementary step, C{sub 2}H{sub 5} + O{sub 2} {leftrightarrow} C{sub 2}H{sub 4} + HO{sub 2}, with the rate coefficient, k(T) = 3.19 x 10{sup {minus}17} T{sup 1.02} exp(2035/RT) cm{sup 3}/molec.-sec., independent of pressure even though the intermediate collision complex may suffer a large number of collisions.

  17. Theoretical analysis of dynamic chemical imaging with lasers using high-order harmonic generation

    SciTech Connect

    Van-Hoang Le; Anh-Thu Le; Xie Ruihua; Lin, C. D.

    2007-07-15

    We report theoretical investigations of the tomographic procedure suggested by Itatani et al. [Nature (London) 432, 867 (2004)] for reconstructing highest occupied molecular orbitals (HOMOs) using high-order harmonic generation (HHG). Due to the limited range of harmonics from the plateau region, we found that even under the most favorable assumptions, it is still very difficult to obtain accurate HOMO wave functions using the tomographic procedure, but the symmetry of the HOMOs and the internuclear separation between the atoms can be accurately extracted, especially when lasers of longer wavelengths are used to generate the HHG. Since the tomographic procedure relies on approximating the continuum wave functions in the recombination process by plane waves, the method can no longer be applied upon the improvement of the theory. For future chemical imaging with lasers, we suggest that one may want to focus on how to extract the positions of atoms in molecules instead, by developing an iterative method such that the theoretically calculated macroscopic HHG spectra can best fit the experimental HHG data.

  18. Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

    NASA Astrophysics Data System (ADS)

    Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

    Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

  19. Theoretical performance assessment and empirical analysis of super-resolution under unknown affine sensor motion.

    PubMed

    Thelen, Brian J; Valenzuela, John R; LeBlanc, Joel W

    2016-04-01

    This paper deals with super-resolution (SR) processing and associated theoretical performance assessment for under-sampled video data collected from a moving imaging platform with unknown motion and assuming a relatively flat scene. This general scenario requires joint estimation of the high-resolution image and the parameters that determine a projective transform that relates the collected frames to one another. A quantitative assessment of the variance in the random error as achieved through a joint-estimation approach (e.g., SR image reconstruction and motion estimation) is carried out via the general framework of M-estimators and asymptotic statistics. This approach provides a performance measure on estimating the fine-resolution scene when there is a lack of perspective information and represents a significant advancement over previous work that considered only the more specific scenario of mis-registration. A succinct overview of the theoretical framework is presented along with some specific results on the approximate random error for the case of unknown translation and affine motions. A comparison is given between the approximated random error and that actually achieved by an M-estimator approach to the joint-estimation problem. These results provide insight on the reduction in SR reconstruction accuracy when jointly estimating unknown inter-frame affine motion.

  20. Theoretical Analysis of a Cascaded Continuous-Wave Optical Parametric Oscillator

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Li, Xiao; Xu, Xiaojun; Wang, Hongyan; Jiang, Zongfu

    2013-04-01

    Threshold and conversion efficiency of a cascaded continuous-wave (CW) optical parametric oscillator (OPO) which can obtain CW terahertz (THz) light are analyzed by the plane wave approach. The model predicts experimental results of the first-order cascaded threshold. The theoretically predicted threshold for the backward idler parametric process agrees with the experimental data. Validation with a high-order cascaded parametric process awaits completion of experiments. At a pump wavelength of 1,030 nm and temperature of 120 °C, the threshold intensity of the forward idler parametric process was 2.2-2.4 times that of the backward process when the period length of the MgO:periodically poled lithium niobate crystal was 24-30 μm. The energy efficiency of CW THz light at a cascade order smaller than 6 is 10-5-10-4. Moreover, efficiency of N cascaded processes can be increased by a factor of N compared with that of a single parametric process, which is limited by the Manley-Rowe relationship. To our knowledge, this is the first theoretical treatment of threshold and energy efficiency of a cascaded CW OPO.