WorldWideScience

Sample records for length scales dependent

  1. Length-scale dependent phonon interactions

    CERN Document Server

    Srivastava, Gyaneshwar

    2014-01-01

    This book presents  a comprehensive description of phonons and their interactions in systems with different dimensions and length scales. Internationally-recognized leaders describe theories and measurements of phonon interactions  in relation to the design of materials with exotic properties such as metamaterials, nano-mechanical systems, next-generation electronic, photonic, and acoustic devices, energy harvesting, optical information storage, and applications of phonon lasers in a variety of fields. The emergence of techniques for control of semiconductor properties and geometry has enabled engineers to design structures in which functionality is derived from controlling electron behavior. As manufacturing techniques have greatly expanded the list of available materials and the range of attainable length scales, similar opportunities now exist for designing devices whose functionality is derived from controlling phonon behavior. However, progress in this area is hampered by gaps in our knowledge of phono...

  2. Length-scale dependent ensemble-averaged conductance of a 1D disordered conductor: Conductance minimum

    International Nuclear Information System (INIS)

    Tit, N.; Kumar, N.; Pradhan, P.

    1993-07-01

    Exact numerical calculation of ensemble averaged length-scale dependent conductance for the 1D Anderson model is shown to support an earlier conjecture for a conductance minimum. Numerical results can be understood in terms of the Thouless expression for the conductance and the Wigner level-spacing statistics. (author). 8 refs, 2 figs

  3. Dependence of exponents on text length versus finite-size scaling for word-frequency distributions

    Science.gov (United States)

    Corral, Álvaro; Font-Clos, Francesc

    2017-08-01

    Some authors have recently argued that a finite-size scaling law for the text-length dependence of word-frequency distributions cannot be conceptually valid. Here we give solid quantitative evidence for the validity of this scaling law, using both careful statistical tests and analytical arguments based on the generalized central-limit theorem applied to the moments of the distribution (and obtaining a novel derivation of Heaps' law as a by-product). We also find that the picture of word-frequency distributions with power-law exponents that decrease with text length [X. Yan and P. Minnhagen, Physica A 444, 828 (2016), 10.1016/j.physa.2015.10.082] does not stand with rigorous statistical analysis. Instead, we show that the distributions are perfectly described by power-law tails with stable exponents, whose values are close to 2, in agreement with the classical Zipf's law. Some misconceptions about scaling are also clarified.

  4. Scale and time dependence of serial correlations in word-length time series of written texts

    Science.gov (United States)

    Rodriguez, E.; Aguilar-Cornejo, M.; Femat, R.; Alvarez-Ramirez, J.

    2014-11-01

    This work considered the quantitative analysis of large written texts. To this end, the text was converted into a time series by taking the sequence of word lengths. The detrended fluctuation analysis (DFA) was used for characterizing long-range serial correlations of the time series. To this end, the DFA was implemented within a rolling window framework for estimating the variations of correlations, quantified in terms of the scaling exponent, strength along the text. Also, a filtering derivative was used to compute the dependence of the scaling exponent relative to the scale. The analysis was applied to three famous English-written literary narrations; namely, Alice in Wonderland (by Lewis Carrol), Dracula (by Bram Stoker) and Sense and Sensibility (by Jane Austen). The results showed that high correlations appear for scales of about 50-200 words, suggesting that at these scales the text contains the stronger coherence. The scaling exponent was not constant along the text, showing important variations with apparent cyclical behavior. An interesting coincidence between the scaling exponent variations and changes in narrative units (e.g., chapters) was found. This suggests that the scaling exponent obtained from the DFA is able to detect changes in narration structure as expressed by the usage of words of different lengths.

  5. The length-scale dependence of strain in networks by SANS

    CERN Document Server

    Pyckhout-Hintzen, W; Heinrich, M; Richter, D; Westermann, S; Straube, E

    2002-01-01

    We present a SANS study of the length-scale dependence of chain deformation by means of a suitable labeling in dense, cross-linked elastomers of the HDH-type. This length scale is controlled by the size of the label as well as the cross-link density. The results are compared to long homopolymers. The data are analyzed by means of the tube model of topology in rubber elasticity in combination with the random-phase approximation (RPA) to account for interchain correlations. Chain degradation during cross linking is treated by the standard RPA approach for polydisperse multicomponent systems. A transition from locally freely fluctuating to tube-constrained segmental motion was observed. (orig.)

  6. Myofilament length dependent activation

    Energy Technology Data Exchange (ETDEWEB)

    de Tombe, Pieter P.; Mateja, Ryan D.; Tachampa, Kittipong; Mou, Younss Ait; Farman, Gerrie P.; Irving, Thomas C. (IIT); (Loyola)

    2010-05-25

    The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca{sup 2+} ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the 'Frank-Starling law of the heart' constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.

  7. Length Scale Dependence of the Dynamic Properties of Hyaluronic Acid Solutions in the Presence of Salt

    Energy Technology Data Exchange (ETDEWEB)

    Horkay, Ferenc; Falus, Peter; Hecht, Anne-Marie; Geissler, Erik (CNRS-UMR); (NIH); (ILL)

    2010-12-07

    In solutions of the charged semirigid biopolymer hyaluronic acid in salt-free conditions, the diffusion coefficient D{sub NSE} measured at high transfer momentum q by neutron spin echo is more than an order of magnitude smaller than that determined by dynamic light scattering, D{sub DLS}. This behavior contrasts with neutral polymer solutions. With increasing salt content, D{sub DLS} approaches D{sub NSE}, which is independent of ionic strength. Contrary to theoretical expectation, the ion-polymer coupling, which dominates the low q dynamics of polyelectrolyte solutions, already breaks down at distance scales greater than the Debye-Hueckel length.

  8. Motion of nanoprobes in complex liquids within the framework of the length-scale dependent viscosity model.

    Science.gov (United States)

    Kalwarczyk, Tomasz; Sozanski, Krzysztof; Ochab-Marcinek, Anna; Szymanski, Jedrzej; Tabaka, Marcin; Hou, Sen; Holyst, Robert

    2015-09-01

    This paper deals with the recent phenomenological model of the motion of nanoscopic objects (colloidal particles, proteins, nanoparticles, molecules) in complex liquids. We analysed motion in polymer, micellar, colloidal and protein solutions and the cytoplasm of living cells using the length-scale dependent viscosity model. Viscosity monotonically approaches macroscopic viscosity as the size of the object increases and thus gives a single, coherent picture of motion at the nano and macro scale. The model includes interparticle interactions (solvent-solute), temperature and the internal structure of a complex liquid. The depletion layer ubiquitously occurring in complex liquids is also incorporated into the model. We also discuss the biological aspects of crowding in terms of the length-scale dependent viscosity model. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

    Science.gov (United States)

    Javvaji, Brahmanandam; Raha, S.; Mahapatra, D. Roy

    2017-02-01

    Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

  10. Length-scale and strain rate-dependent mechanism of defect formation and fracture in carbon nanotubes under tensile loading

    Energy Technology Data Exchange (ETDEWEB)

    Javvaji, Brahmanandam [Indian Institute of Science, Department of Aerospace Engineering (India); Raha, S. [Indian Institute of Science, Department of Computational and Data Sciences (India); Mahapatra, D. Roy, E-mail: droymahapatra@aero.iisc.ernet.in [Indian Institute of Science, Department of Aerospace Engineering (India)

    2017-02-15

    Electromagnetic and thermo-mechanical forces play a major role in nanotube-based materials and devices. Under high-energy electron transport or high current densities, carbon nanotubes fail via sequential fracture. The failure sequence is governed by certain length scale and flow of current. We report a unified phenomenological model derived from molecular dynamic simulation data, which successfully captures the important physics of the complex failure process. Length-scale and strain rate-dependent defect nucleation, growth, and fracture in single-walled carbon nanotubes with diameters in the range of 0.47 to 2.03 nm and length which is about 6.17 to 26.45 nm are simulated. Nanotubes with long length and small diameter show brittle fracture, while those with short length and large diameter show transition from ductile to brittle fracture. In short nanotubes with small diameters, we observe several structural transitions like Stone-Wales defect initiation, its propagation to larger void nucleation, formation of multiple chains of atoms, conversion to monatomic chain of atoms, and finally complete fracture of the carbon nanotube. Hybridization state of carbon-carbon bonds near the end cap evolves, leading to the formation of monatomic chain in short nanotubes with small diameter. Transition from ductile to brittle fracture is also observed when strain rate exceeds a critical value. A generalized analytical model of failure is established, which correlates the defect energy during the formation of atomic chain with aspect ratio of the nanotube and strain rate. Variation in the mechanical properties such as elastic modulus, tensile strength, and fracture strain with the size and strain rate shows important implications in mitigating force fields and ways to enhance the life of electronic devices and nanomaterial conversion via fracture in manufacturing.

  11. Length-scale dependent microalloying effects on precipitation behaviors and mechanical properties of Al–Cu alloys with minor Sc addition

    International Nuclear Information System (INIS)

    Jiang, L.; Li, J.K.; Liu, G.; Wang, R.H.; Chen, B.A.; Zhang, J.Y.; Sun, J.; Yang, M.X.; Yang, G.; Yang, J.; Cao, X.Z.

    2015-01-01

    Heat-treatable Al alloys containing Al–2.5 wt% Cu (Al–Cu) and Al–2.5 wt% Cu–0.3 wt% Sc (Al–Cu–Sc) with different grain length scales, i.e., average grain size >10 μm ( defined coarse grained, CG), 1–2 μm (fine grained, FG), and <1 μm (ultrafine grained, UFG), were prepared by equal-channel angular pressing (ECAP). The length scale and Sc microalloying effects and their interplay on the precipitation behavior and mechanical properties of the Al–Cu alloys were systematically investigated. In the Al–Cu alloys, intergranular θ-Al 2 Cu precipitation gradually dominated by sacrificing the intragranular θ′-Al 2 Cu precipitation with reducing the length scale. Especially in the UFG regime, only intergranular θ-Al 2 Cu particles were precipitated and intragranular θ′-Al 2 Cu precipitation was completely disappeared. This led to a remarkable reduction in yield strength and ductility due to insufficient dislocation storage capacity. The minor Sc addition resulted in a microalloying effect in the Al–Cu alloy, which, however, is strongly dependent on the length scale. The smaller is the grain size, the more active is the microalloying effect that promotes the intragranular precipitation while reduces the intergranular precipitation. Correspondingly, compared with their Sc-free counterparts, the yield strength of post-aged CG, FG, and UFG Al–Cu alloys with Sc addition increased by ~36 MPa, ~56 MPa, and ~150 MPa, simultaneously in tensile elongation by ~20%, ~30%, and 280%, respectively. The grain size-induced evolutions in vacancy concentration/distribution and number density of vacancy-solute/solute–solute clusters and their influences on precipitation nucleation and kinetics have been comprehensively considered to rationalize the length scale-dependent Sc microalloying mechanisms using positron annihilation lifetime spectrum and three dimension atom probe. The increase in ductility was analyzed in the light of Sc microalloying effect and the

  12. Length-scale dependent microalloying effects on precipitation behaviors and mechanical properties of Al–Cu alloys with minor Sc addition

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, L.; Li, J.K. [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, G., E-mail: lgsammer@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, R.H. [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Chen, B.A.; Zhang, J.Y. [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Sun, J., E-mail: junsun@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Yang, M.X.; Yang, G. [Central Iron and Steel Research Institute, Beijing 100081 (China); Yang, J.; Cao, X.Z. [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-06-18

    Heat-treatable Al alloys containing Al–2.5 wt% Cu (Al–Cu) and Al–2.5 wt% Cu–0.3 wt% Sc (Al–Cu–Sc) with different grain length scales, i.e., average grain size >10 μm ( defined coarse grained, CG), 1–2 μm (fine grained, FG), and <1 μm (ultrafine grained, UFG), were prepared by equal-channel angular pressing (ECAP). The length scale and Sc microalloying effects and their interplay on the precipitation behavior and mechanical properties of the Al–Cu alloys were systematically investigated. In the Al–Cu alloys, intergranular θ-Al{sub 2}Cu precipitation gradually dominated by sacrificing the intragranular θ′-Al{sub 2}Cu precipitation with reducing the length scale. Especially in the UFG regime, only intergranular θ-Al{sub 2}Cu particles were precipitated and intragranular θ′-Al{sub 2}Cu precipitation was completely disappeared. This led to a remarkable reduction in yield strength and ductility due to insufficient dislocation storage capacity. The minor Sc addition resulted in a microalloying effect in the Al–Cu alloy, which, however, is strongly dependent on the length scale. The smaller is the grain size, the more active is the microalloying effect that promotes the intragranular precipitation while reduces the intergranular precipitation. Correspondingly, compared with their Sc-free counterparts, the yield strength of post-aged CG, FG, and UFG Al–Cu alloys with Sc addition increased by ~36 MPa, ~56 MPa, and ~150 MPa, simultaneously in tensile elongation by ~20%, ~30%, and 280%, respectively. The grain size-induced evolutions in vacancy concentration/distribution and number density of vacancy-solute/solute–solute clusters and their influences on precipitation nucleation and kinetics have been comprehensively considered to rationalize the length scale-dependent Sc microalloying mechanisms using positron annihilation lifetime spectrum and three dimension atom probe. The increase in ductility was analyzed in the light of Sc microalloying

  13. Mixing lengths scaling in a gravity flow

    Energy Technology Data Exchange (ETDEWEB)

    Ecke, Robert E [Los Alamos National Laboratory; Rivera, Micheal [Los Alamos National Laboratory; Chen, Jun [Los Alamos National Laboratory; Ecke, Robert E [Los Alamos National Laboratory

    2009-01-01

    We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model [1]: the turbulent vertical fluxes of momentum and buoyancy are found to scale quadraticatly with the vertical mean gradients of velocity and density. The scaling coefficient is the square of the mixing length, approximately constant over the mixing zone of the stratified shear layer. We show in this paper how, in different flow configurations, this length can be related to the shear length of the flow {radical}({var_epsilon}/{partial_derivative}{sub z}u{sup 3}).

  14. Minimal Length Scale Scenarios for Quantum Gravity.

    Science.gov (United States)

    Hossenfelder, Sabine

    2013-01-01

    We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.

  15. Minimal Length Scale Scenarios for Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Sabine Hossenfelder

    2013-01-01

    Full Text Available We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.

  16. Topographical length scales of hierarchical superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Dhillon, P.K. [Department of Physics, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab 140001 (India); Brown, P.S.; Bain, C.D.; Badyal, J.P.S. [Department of Chemistry, Science Laboratories, Durham University, Durham DH1 3LE, England (United Kingdom); Sarkar, S., E-mail: sarkar@iitrpr.ac.in [Department of Physics, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab 140001 (India)

    2014-10-30

    Highlights: • Hydrophobic CF{sub 4} plasma fluorinated polybutadiene surfaces has been characterised using AFM. • Micro, Nano, and Micro + Nano topographies generated by altering plasma power and duration. • Dynamic scaling theory and FFT analysis used to characterize these surfaces quantitatively. • Roughnesses are different for different length scales of the surfaces considered. • Highest local roughness obtained from scaling analysis for shorter length scales of about 500 nm explains the superhydrophobicity for the Micro + Nano surface. - Abstract: The morphology of hydrophobic CF{sub 4} plasma fluorinated polybutadiene surfaces has been characterised using atomic force microscopy (AFM). Judicious choice of the plasma power and exposure duration leads to formation of three different surface morphologies (Micro, Nano, and Micro + Nano). Scaling theory analysis shows that for all three surface topographies, there is an initial increase in roughness with length scale followed by a levelling-off to a saturation level. At length scales around 500 nm, it is found that the roughness is very similar for all three types of surfaces, and the saturation roughness value for the Micro + Nano morphology is found to be intermediate between those for the Micro and Nano surfaces. Fast Fourier Transform (FFT) analysis has shown that the Micro + Nano topography comprises a hierarchical superposition of Micro and Nano morphologies. Furthermore, the Micro + Nano surfaces display the highest local roughness (roughness exponent α = 0.42 for length scales shorter than ∼500 nm), which helps to explain their superhydrophobic behaviour (large water contact angle (>170°) and low hysteresis (<1°))

  17. Critical length scales for flow phenomena in liquid metal batteries

    Science.gov (United States)

    Kelley, Douglas; Weier, Tom

    2017-11-01

    Liquid metal batteries, a new technology for grid-scale energy storage, are composed of three liquid layers and therefore subject to a wide variety of fluid dynamical phenomena, both beneficial and detrimental. Some, like thermal convection and electrovortex flow, drive finite flow regardless of the size, current density, and temperature of the battery. Others, like the Tayler instability and the metal pad instability, occur only in certain parameter regimes - almost always dependent on length scale. I will discuss critical length scales, considering implications for battery design in light of fundamental fluid dynamics. This work was supported by the National Science Foundation under Award Number CBET-1552182.

  18. Determining multiple length scales in rocks

    Science.gov (United States)

    Song, Yi-Qiao; Ryu, Seungoh; Sen, Pabitra N.

    2000-07-01

    Carbonate reservoirs in the Middle East are believed to contain about half of the world's oil. The processes of sedimentation and diagenesis produce in carbonate rocks microporous grains and a wide range of pore sizes, resulting in a complex spatial distribution of pores and pore connectivity. This heterogeneity makes it difficult to determine by conventional techniques the characteristic pore-length scales, which control fluid transport properties. Here we present a bulk-measurement technique that is non-destructive and capable of extracting multiple length scales from carbonate rocks. The technique uses nuclear magnetic resonance to exploit the spatially varying magnetic field inside the pore space itself-a `fingerprint' of the pore structure. We found three primary length scales (1-100µm) in the Middle-East carbonate rocks and determined that the pores are well connected and spatially mixed. Such information is critical for reliably estimating the amount of capillary-bound water in the rock, which is important for efficient oil production. This method might also be used to complement other techniques for the study of shaly sand reservoirs and compartmentalization in cells and tissues.

  19. Length and time scales of atmospheric moisture recycling

    Directory of Open Access Journals (Sweden)

    R. J. van der Ent

    2011-03-01

    Full Text Available It is difficult to quantify the degree to which terrestrial evaporation supports the occurrence of precipitation within a certain study region (i.e. regional moisture recycling due to the scale- and shape-dependence of regional moisture recycling ratios. In this paper we present a novel approach to quantify the spatial and temporal scale of moisture recycling, independent of the size and shape of the region under study. In contrast to previous studies, which essentially used curve fitting, the scaling laws presented by us follow directly from the process equation. thus allowing a fair comparison between regions and seasons. The calculation is based on ERA-Interim reanalysis data for the period 1999 to 2008. It is shown that in the tropics or in mountainous terrain the length scale of recycling can be as low as 500 to 2000 km. In temperate climates the length scale is typically between 3000 to 5000 km whereas it amounts to more than 7000 km in desert areas. The time scale of recycling ranges from 3 to 20 days, with the exception of deserts, where it is much longer. The most distinct seasonal differences can be observed over the Northern Hemisphere: in winter, moisture recycling is insignificant, whereas in summer it plays a major role in the climate. The length and time scales of atmospheric moisture recycling can be useful metrics to quantify local climatic effects of land use change.

  20. Interplay between multiple length and time scales in complex ...

    Indian Academy of Sciences (India)

    Administrator

    micelles and enzymes, can span several orders of magnitude in length and time scales. The length and time scales of ... length and time scales is required in order to understand and predict structure and dynamics in such com- plex systems. This review .... The late 1980s saw the birth of femtochemistry with Ahmed Zewail ...

  1. Scattering Length Scaling Laws for Ultracold Three-Body Collisions

    International Nuclear Information System (INIS)

    D'Incao, J.P.; Esry, B.D.

    2005-01-01

    We present a simple and unifying picture that provides the energy and scattering length dependence for all inelastic three-body collision rates in the ultracold regime for three-body systems with short-range two-body interactions. Here, we present the scaling laws for vibrational relaxation, three-body recombination, and collision-induced dissociation for systems that support s-wave two-body collisions. These systems include three identical bosons, two identical bosons, and two identical fermions. Our approach reproduces all previous results, predicts several others, and gives the general form of the scaling laws in all cases

  2. Length Scales in Bayesian Automatic Adaptive Quadrature

    Directory of Open Access Journals (Sweden)

    Adam Gh.

    2016-01-01

    Full Text Available Two conceptual developments in the Bayesian automatic adaptive quadrature approach to the numerical solution of one-dimensional Riemann integrals [Gh. Adam, S. Adam, Springer LNCS 7125, 1–16 (2012] are reported. First, it is shown that the numerical quadrature which avoids the overcomputing and minimizes the hidden floating point loss of precision asks for the consideration of three classes of integration domain lengths endowed with specific quadrature sums: microscopic (trapezoidal rule, mesoscopic (Simpson rule, and macroscopic (quadrature sums of high algebraic degrees of precision. Second, sensitive diagnostic tools for the Bayesian inference on macroscopic ranges, coming from the use of Clenshaw-Curtis quadrature, are derived.

  3. Length Scales in Bayesian Automatic Adaptive Quadrature

    Science.gov (United States)

    Adam, Gh.; Adam, S.

    2016-02-01

    Two conceptual developments in the Bayesian automatic adaptive quadrature approach to the numerical solution of one-dimensional Riemann integrals [Gh. Adam, S. Adam, Springer LNCS 7125, 1-16 (2012)] are reported. First, it is shown that the numerical quadrature which avoids the overcomputing and minimizes the hidden floating point loss of precision asks for the consideration of three classes of integration domain lengths endowed with specific quadrature sums: microscopic (trapezoidal rule), mesoscopic (Simpson rule), and macroscopic (quadrature sums of high algebraic degrees of precision). Second, sensitive diagnostic tools for the Bayesian inference on macroscopic ranges, coming from the use of Clenshaw-Curtis quadrature, are derived.

  4. Microtubule length dependence of motor traffic in cells.

    Science.gov (United States)

    Zhang, Yunxin

    2012-10-01

    Motor proteins in living cells, such as kinesin and dynein, can move processively along the microtubule (MT), and can also detach from or attach to MT stochastically. Experiments found that the traffic of motors along MT may be jammed; thus various theoretical models were designed to understand this process. However, previous studies mainly focused on motor attachment/detachment rate dependent properties. Leduc et al. recently found that the traffic jam of motor protein Kip3 depends on MT length (Proc. Natl. Acad. Sci. U.S.A. 109, 6100 (2012)). Therefore, this study discusses the MT length-dependent properties of motor traffic. The results showed that MT length has one critical value N(c); a traffic jam occurs only when MT length N > N(c). The jammed MT length increases with total MT length N , whereas the non-jammed MT length may not change monotonically with N . The critical value N(c) increases with motor detachment rate from MT, but decreases with motor attachment rate to MT. Therefore, the traffic of motors will be more likely to be jammed when the MT is long, motor detachment rate is high, and motor detachment rate is low.

  5. On the thermal stability length dependence of high TC superconductors

    International Nuclear Information System (INIS)

    Maytal, B.Z.; Yang, S.; Waldrop, J.; Pfotenhauer, J.M.

    1996-01-01

    The margin of stability for high T c superconductors may be characterized by the lowest thermal pulse that results in a quench. A numerical code, developed to investigate this stability margin, accounts for the temperature dependence of the thermal conductivity, electrical resistivity and heat capacity of the materials involved. The conductor is cooled solely by thermal conduction along its length, and its stability is studied as function of the length. It is found that the stability margin for a pure BSCCO 2212 conductor is independent of the length. However, the stability margin for a composite conductor obtained by adding 10 % (by volume) of silver to the BSCCO is found to be strongly length dependent. A transition length is identified, for which shorter lengths exhibit a dramatically higher stability margin. This feature results when the length dependent thermal diffusion time is shorter than the time required to determine the conductor's stability. This study confirms and explains the growing awareness that if normal zones appear in high T c coils, they will remain fairly localized

  6. Density Functional Theory and Materials Modeling at Atomistic Length Scales

    Directory of Open Access Journals (Sweden)

    Swapan K. Ghosh

    2002-04-01

    Full Text Available Abstract: We discuss the basic concepts of density functional theory (DFT as applied to materials modeling in the microscopic, mesoscopic and macroscopic length scales. The picture that emerges is that of a single unified framework for the study of both quantum and classical systems. While for quantum DFT, the central equation is a one-particle Schrodinger-like Kohn-Sham equation, the classical DFT consists of Boltzmann type distributions, both corresponding to a system of noninteracting particles in the field of a density-dependent effective potential, the exact functional form of which is unknown. One therefore approximates the exchange-correlation potential for quantum systems and the excess free energy density functional or the direct correlation functions for classical systems. Illustrative applications of quantum DFT to microscopic modeling of molecular interaction and that of classical DFT to a mesoscopic modeling of soft condensed matter systems are highlighted.

  7. Chemical theory and modelling through density across length scales

    International Nuclear Information System (INIS)

    Ghosh, Swapan K.

    2016-01-01

    One of the concepts that has played a major role in the conceptual as well as computational developments covering all the length scales of interest in a number of areas of chemistry, physics, chemical engineering and materials science is the concept of single-particle density. Density functional theory has been a versatile tool for the description of many-particle systems across length scales. Thus, in the microscopic length scale, an electron density based description has played a major role in providing a deeper understanding of chemical binding in atoms, molecules and solids. Density concept has been used in the form of single particle number density in the intermediate mesoscopic length scale to obtain an appropriate picture of the equilibrium and dynamical processes, dealing with a wide class of problems involving interfacial science and soft condensed matter. In the macroscopic length scale, however, matter is usually treated as a continuous medium and a description using local mass density, energy density and other related property density functions has been found to be quite appropriate. The basic ideas underlying the versatile uses of the concept of density in the theory and modelling of materials and phenomena, as visualized across length scales, along with selected illustrative applications to some recent areas of research on hydrogen energy, soft matter, nucleation phenomena, isotope separation, and separation of mixture in condensed phase, will form the subject matter of the talk. (author)

  8. Sequence-Dependent Persistence Length of Long DNA

    Science.gov (United States)

    Chuang, Hui-Min; Reifenberger, Jeffrey G.; Cao, Han; Dorfman, Kevin D.

    2017-12-01

    Using a high-throughput genome-mapping approach, we obtained circa 50 million measurements of the extension of internal human DNA segments in a 41 nm ×41 nm nanochannel. The underlying DNA sequences, obtained by mapping to the reference human genome, are 2.5-393 kilobase pairs long and contain percent GC contents between 32.5% and 60%. Using Odijk's theory for a channel-confined wormlike chain, these data reveal that the DNA persistence length increases by almost 20% as the percent GC content increases. The increased persistence length is rationalized by a model, containing no adjustable parameters, that treats the DNA as a statistical terpolymer with a sequence-dependent intrinsic persistence length and a sequence-independent electrostatic persistence length.

  9. On transition in plasma turbulence with multiple scale lengths

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, K.; Spineanu, F.; Vlad, M.O. [National Inst. for Fusion Science, Toki, Gifu (Japan); Itoh, S.-I.; Kawasaki, M. [Kyushu Univ., Research Institute for Applied Mechanics, Kasuga, Fukuoka (Japan)

    2003-05-01

    A statistical theory of plasma turbulence which is composed of multiple-scale fluctuations is examined. Influences of statistical noise and variance of rapidly-changing variable in an adiabatic approximation are investigated. It is confirmed that the contributions of noise and variance remain higher order corrections. Transition rate of the turbulence with multiple scale lengths is obtained under the refined adiabatic approximation. (author)

  10. Maximum length scale in density based topology optimization

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov; Wang, Fengwen

    2017-01-01

    The focus of this work is on two new techniques for imposing maximum length scale in topology optimization. Restrictions on the maximum length scale provide designers with full control over the optimized structure and open possibilities to tailor the optimized design for broader range...... of manufacturing processes by fulfilling the associated technological constraints. One of the proposed methods is based on combination of several filters and builds on top of the classical density filtering which can be viewed as a low pass filter applied to the design parametrization. The main idea...

  11. Analysis Models for Polymer Composites Across Different Length Scales

    Science.gov (United States)

    Camanho, Pedro P.; Arteiro, Albertino

    This chapter presents the analysis models, developed at different length scales, for the prediction of inelastic deformation and fracture of polymer composite materials reinforced by unidirectional fibers. Three different length scales are covered. Micro-mechanical models are used to understand in detail the effects of the constituents on the response of the composite material, and to support the development of analysis models based on homogenized representations of composite materials. Meso-mechanical models are used to predict the strength of composite structural components under general loading conditions. Finally, macro-mechanical models based on Finite Fracture Mechanics, which enable fast strength predictions of simple structural details, are discussed.

  12. The dependence of scattering length on van der Waals interaction ...

    Indian Academy of Sciences (India)

    2016-06-16

    Jun 16, 2016 ... DOI 10.1007/s12043-016-1221-y. The dependence of scattering length on van der Waals interaction and reduced mass of the system in two-atomic collision at cold energies. HASI RAY1,2,3,4. 1Study Centre, S-1/407/6, B.P. Township, Kolkata 700 094, India. 2Department of Physics, New Alipore College, ...

  13. Length Scale of Leidenfrost Ratchet Switches Droplet Directionality

    Energy Technology Data Exchange (ETDEWEB)

    Agapov, Rebecca L [ORNL; Boreyko, Jonathan B [ORNL; Briggs, Dayrl P [ORNL; Srijanto, Bernadeta R [ORNL; Retterer, Scott T [ORNL; Collier, Pat [ORNL; Lavrik, Nickolay V [ORNL

    2014-01-01

    Arrays of tilted pillars with characteristic heights spanning from hundreds of nanometers to tens of micrometers were created using wafer level processing and used as Leidenfrost ratchets to control droplet directionality. Dynamic Leidenfrost droplets on the ratchets with nanoscale features were found to move in the direction of the pillar tilt while the opposite directionality was observed on the microscale ratchets. This remarkable switch in the droplet directionality can be explained by varying contributions from the two distinct mechanisms controlling droplet motion on Leidenfrost ratchets with nanoscale and microscale features. In particular, asymmetric wettability of dynamic Leidenfrost droplets upon initial impact appears to be the dominant mechanism determining their directionality on tilted nanoscale pillar arrays. By contrast, asymmetric wetting does not provide a strong enough driving force compared to the forces induced by asymmetric vapour flow on arrays of much taller tilted microscale pillars. Furthermore, asymmetric wetting plays a role only in the dynamic Leidenfrost regime, for instance when droplets repeatedly jump after their initial impact. The point of crossover between the two mechanisms coincides with the pillar heights comparable to the values of the thinnest vapor layers still capable of cushioning Leidenfrost droplets upon their initial impact. The proposed model of the length scale dependent interplay between the two mechanisms points to the previously unexplored ability to bias movement of dynamic Leidenfrost droplets and even switch their directionality.

  14. Length scale of Leidenfrost ratchet switches droplet directionality.

    Science.gov (United States)

    Agapov, Rebecca L; Boreyko, Jonathan B; Briggs, Dayrl P; Srijanto, Bernadeta R; Retterer, Scott T; Collier, C Patrick; Lavrik, Nickolay V

    2014-08-07

    Arrays of tilted pillars with characteristic heights spanning from hundreds of nanometers to tens of micrometers were created using wafer level processing and used as Leidenfrost ratchets to control droplet directionality. Dynamic Leidenfrost droplets on the ratchets with nanoscale features were found to move in the direction of the pillar tilt while the opposite directionality was observed on the microscale ratchets. This remarkable switch in the droplet directionality can be explained by varying contributions from the two distinct mechanisms controlling droplet motion on Leidenfrost ratchets with nanoscale and microscale features. In particular, asymmetric wettability of dynamic Leidenfrost droplets upon initial impact appears to be the dominant mechanism determining their directionality on tilted nanoscale pillar arrays. By contrast, asymmetric wetting does not provide a strong enough driving force compared to the forces induced by asymmetric vapour flow on arrays of much taller tilted microscale pillars. Furthermore, asymmetric wetting plays a role only in the dynamic Leidenfrost regime, for instance when droplets repeatedly jump after their initial impact. The point of crossover between the two mechanisms coincides with the pillar heights comparable to the values of the thinnest vapor layers still capable of cushioning Leidenfrost droplets upon their initial impact. The proposed model of the length scale dependent interplay between the two mechanisms points to the previously unexplored ability to bias movement of dynamic Leidenfrost droplets and even switch their directionality.

  15. A New Universal Gas Breakdown Theory for Classical Length Scales

    Science.gov (United States)

    Loveless, Amanda Mae

    While Paschen's law is commonly used to predict breakdown voltage, it fails at microscale gaps when field emission becomes important. Accurate breakdown voltage predictions at microscale are even more important as electronic device dimensions decrease. Developing analytic models to accurately predict breakdown at microscale is vital for understanding the underlying physics occurring within the system and to either prevent or produce a discharge, depending on the application. We first take a pre-existing breakdown model coupling field emission and Townsend breakdown and perform a matched asymptotic analysis to obtain analytic equations for breakdown voltage in argon at atmospheric pressure. Next, we extend this model to generalize for gas and further explore the independent contributions of field emission and Townsend discharge. Finally, we present analytic expressions for breakdown voltage valid for any gas at any pressure, and discuss the modified Paschen minimum at microscale. The presented models agree well with numerical simulations and experimental data when using the field enhancement factor as a fitting parameter. The work presented in this thesis is a first step in unifying gas breakdown across length scales and breakdown mechanisms. Future work will aim to incorporate other breakdown mechanisms, such as quantum effects and space charge, to provide a more complete unified model for gas breakdown.

  16. Length scales and selforganization in dense suspension flows

    NARCIS (Netherlands)

    Düring, G.; Lerner, E.; Wyart, M.

    2014-01-01

    Dense non-Brownian suspension flows of hard particles display mystifying properties: As the jamming threshold is approached, the viscosity diverges, as well as a length scale that can be identified from velocity correlations. To unravel the microscopic mechanism governing dissipation and its

  17. Internal Length Gradient (ILG) Material Mechanics Across Scales & Disciplines

    OpenAIRE

    Aifantis, Elias C.

    2016-01-01

    A combined theoretical/numerical/experimental program is outlined for extending the ILG approach to consider time lags, stochasticity and multiphysics couplings. Through this extension it is possible to discuss the interplay between deformation internal lengths (ILs) and ILs induced by thermal, diffusion or electric field gradients. Size-dependent multiphysics stability diagrams are obtained, and size-dependent serrated stress-strain curves are interpreted through combined gradient-stochastic...

  18. Nonmonotonic DNA-length-dependent mobility in pluronic gels

    Science.gov (United States)

    You, Seungyong; Wei, Ling; Shanbhag, Sachin; Van Winkle, David H.

    2017-04-01

    Two-dimensional electrophoresis was used to analyze the mobility of DNA fragments in micellar gels of pluronic F127 (E O100P O70E O100 ) and pluronic P123 (E O20P O70E O20 ) . The 20-3500 base pair DNA fragments were separated by size first in agarose gels, and then in pluronic gels at room temperature. In agarose gels, the DNA mobility decreases monotonically with increasing DNA length. In pluronic gels, however, the mobility varies nonmonotonically according to fragment lengths that are strongly correlated with the diameter of the spherical micelles. Brownian dynamics (BD) simulations with short-ranged intra-DNA hydrodynamic interactions were performed to numerically calculate the length-dependent mobility in pluronic lattices. The rising and falling trends, as well as the oscillations of mobility, were captured by the coarse-grained BD simulations. Molecular dynamics simulations in pluronic F127, with explicitly modeled micelle coronas, justified that the hydrodynamic interactions mediated by the complex fluid of hydrated poly(ethylene oxide) are a possible reason for the initial rise of mobility with DNA length.

  19. Progress in Long Scale Length Laser-Plasma Interactions

    International Nuclear Information System (INIS)

    Glenzer, S H; Arnold, P; Bardsley, G; Berger, R L; Bonanno, G; Borger, T; Bower, D E; Bowers, M; Bryant, R; Buckman, S.; Burkhart, S C; Campbell, K; Chrisp, M P; Cohen, B I; Constantin, G; Cooper, F; Cox, J; Dewald, E; Divol, L; Dixit, S; Duncan, J; Eder, D; Edwards, J; Erbert, G; Felker, B; Fornes, J; Frieders, G; Froula, D H; Gardner, S D; Gates, C; Gonzalez, M; Grace, S; Gregori, G; Greenwood, A; Griffith, R; Hall, T; Hammel, B A; Haynam, C; Heestand, G; Henesian, M; Hermes, G; Hinkel, D; Holder, J; Holdner, F; Holtmeier, G; Hsing, W; Huber, S; James, T; Johnson, S; Jones, O S; Kalantar, D; Kamperschroer, J H; Kauffman, R; Kelleher, T; Knight, J; Kirkwood, R K; Kruer, W L; Labiak, W; Landen, O L; Langdon, A B; Langer, S; Latray, D; Lee, A; Lee, F D; Lund, D; MacGowan, B; Marshall, S; McBride, J; McCarville, T; McGrew, L; Mackinnon, A J; Mahavandi, S; Manes, K; Marshall, C; Mertens, E; Meezan, N; Miller, G; Montelongo, S; Moody, J D; Moses, E; Munro, D; Murray, J; Neumann, J; Newton, M; Ng, E; Niemann, C; Nikitin, A; Opsahl, P; Padilla, E; Parham, T; Parrish, G; Petty, C; Polk, M; Powell, C; Reinbachs, I; Rekow, V; Rinnert, R; Riordan, B; Rhodes, M.

    2003-01-01

    The first experiments on the National Ignition Facility (NIF) have employed the first four beams to measure propagation and laser backscattering losses in large ignition-size plasmas. Gas-filled targets between 2 mm and 7 mm length have been heated from one side by overlapping the focal spots of the four beams from one quad operated at 351 nm (3ω) with a total intensity of 2 x 10 15 W cm -2 . The targets were filled with 1 atm of CO 2 producing of up to 7 mm long homogeneously heated plasmas with densities of n e = 6 x 10 20 cm -3 and temperatures of T e = 2 keV. The high energy in a NIF quad of beams of 16kJ, illuminating the target from one direction, creates unique conditions for the study of laser plasma interactions at scale lengths not previously accessible. The propagation through the large-scale plasma was measured with a gated x-ray imager that was filtered for 3.5 keV x rays. These data indicate that the beams interact with the full length of this ignition-scale plasma during the last ∼1 ns of the experiment. During that time, the full aperture measurements of the stimulated Brillouin scattering and stimulated Raman scattering show scattering into the four focusing lenses of 6% for the smallest length (∼2 mm). increasing to 12% for ∼7 mm. These results demonstrate the NIF experimental capabilities and further provide a benchmark for three-dimensional modeling of the laser-plasma interactions at ignition-size scale lengths

  20. Progress in long scale length laser plasma interactions

    Science.gov (United States)

    Glenzer, S. H.; Arnold, P.; Bardsley, G.; Berger, R. L.; Bonanno, G.; Borger, T.; Bower, D. E.; Bowers, M.; Bryant, R.; Buckman, S.; Burkhart, S. C.; Campbell, K.; Chrisp, M. P.; Cohen, B. I.; Constantin, C.; Cooper, F.; Cox, J.; Dewald, E.; Divol, L.; Dixit, S.; Duncan, J.; Eder, D.; Edwards, J.; Erbert, G.; Felker, B.; Fornes, J.; Frieders, G.; Froula, D. H.; Gardner, S. D.; Gates, C.; Gonzalez, M.; Grace, S.; Gregori, G.; Greenwood, A.; Griffith, R.; Hall, T.; Hammel, B. A.; Haynam, C.; Heestand, G.; Henesian, M.; Hermes, G.; Hinkel, D.; Holder, J.; Holdner, F.; Holtmeier, G.; Hsing, W.; Huber, S.; James, T.; Johnson, S.; Jones, O. S.; Kalantar, D.; Kamperschroer, J. H.; Kauffman, R.; Kelleher, T.; Knight, J.; Kirkwood, R. K.; Kruer, W. L.; Labiak, W.; Landen, O. L.; Langdon, A. B.; Langer, S.; Latray, D.; Lee, A.; Lee, F. D.; Lund, D.; MacGowan, B.; Marshall, S.; McBride, J.; McCarville, T.; McGrew, L.; Mackinnon, A. J.; Mahavandi, S.; Manes, K.; Marshall, C.; Menapace, J.; Mertens, E.; Meezan, N.; Miller, G.; Montelongo, S.; Moody, J. D.; Moses, E.; Munro, D.; Murray, J.; Neumann, J.; Newton, M.; Ng, E.; Niemann, C.; Nikitin, A.; Opsahl, P.; Padilla, E.; Parham, T.; Parrish, G.; Petty, C.; Polk, M.; Powell, C.; Reinbachs, I.; Rekow, V.; Rinnert, R.; Riordan, B.; Rhodes, M.; Roberts, V.; Robey, H.; Ross, G.; Sailors, S.; Saunders, R.; Schmitt, M.; Schneider, M. B.; Shiromizu, S.; Spaeth, M.; Stephens, A.; Still, B.; Suter, L. J.; Tietbohl, G.; Tobin, M.; Tuck, J.; Van Wonterghem, B. M.; Vidal, R.; Voloshin, D.; Wallace, R.; Wegner, P.; Whitman, P.; Williams, E. A.; Williams, K.; Winward, K.; Work, K.; Young, B.; Young, P. E.; Zapata, P.; Bahr, R. E.; Seka, W.; Fernandez, J.; Montgomery, D.; Rose, H.

    2004-12-01

    The first experiments on the National Ignition Facility (NIF) have employed the first four beams to measure propagation and laser backscattering losses in large ignition-size plasmas. Gas-filled targets between 2 and 7 mm length have been heated from one side by overlapping the focal spots of the four beams from one quad operated at 351 nm (3ω) with a total intensity of 2 × 1015 W cm-2. The targets were filled with 1 atm of CO2 producing up to 7 mm long homogeneously heated plasmas with densities of ne = 6 × 1020 cm-3 and temperatures of Te = 2 keV. The high energy in an NIF quad of beams of 16 kJ, illuminating the target from one direction, creates unique conditions for the study of laser-plasma interactions at scale lengths not previously accessible. The propagation through the large-scale plasma was measured with a gated x-ray imager that was filtered for 3.5 keV x-rays. These data indicate that the beams interact with the full length of this ignition-scale plasma during the last ~1 ns of the experiment. During that time, the full aperture measurements of the stimulated Brillouin scattering and stimulated Raman scattering show scattering into the four focusing lenses of 3% for the smallest length (~2 mm), increasing to 10-12% for ~7 mm. These results demonstrate the NIF experimental capabilities and further provide a benchmark for three-dimensional modelling of the laser-plasma interactions at ignition-size scale lengths.

  1. Transition in multiple-scale-lengths turbulence in plasmas

    International Nuclear Information System (INIS)

    Itoh, S.-I.; Yagi, M.; Kawasaki, M.; Kitazawa, A.

    2002-02-01

    The statistical theory of strong turbulence in inhomogeneous plasmas is developed for the cases where fluctuations with different scale-lengths coexist. Statistical nonlinear interactions between semi-micro and micro modes are first kept in the analysis as the drag, noise and drive. The nonlinear dynamics determines both the fluctuation levels and the cross field turbulent transport for the fixed global parameters. A quenching or suppressing effect is induced by their nonlinear interplay, even if both modes are unstable when analyzed independently. Influence of the inhomogeneous global radial electric field is discussed. A new insight is given for the physics of internal transport barrier. The thermal fluctuation of the scale length of λ D is assumed to be statistically independent. The hierarchical structure is constructed according to the scale lengths. Transitions in turbulence are found and phase diagrams with cusp type catastrophe are obtained. Dynamics is followed. Statistical properties of the subcritical excitation are discussed. The probability density function (PDF) and transition probability are obtained. Power-laws are obtained in the PDF as well as in the transition probability. Generalization for the case where turbulence is composed of three-classes of modes is also developed. A new catastrophe of turbulent sates is obtained. (author)

  2. Length-dependent prediction of protein intrinsic disorder

    Directory of Open Access Journals (Sweden)

    Dunker A Keith

    2006-04-01

    Full Text Available Abstract Background Due to the functional importance of intrinsically disordered proteins or protein regions, prediction of intrinsic protein disorder from amino acid sequence has become an area of active research as witnessed in the 6th experiment on Critical Assessment of Techniques for Protein Structure Prediction (CASP6. Since the initial work by Romero et al. (Identifying disordered regions in proteins from amino acid sequences, IEEE Int. Conf. Neural Netw., 1997, our group has developed several predictors optimized for long disordered regions (>30 residues with prediction accuracy exceeding 85%. However, these predictors are less successful on short disordered regions (≤30 residues. A probable cause is a length-dependent amino acid compositions and sequence properties of disordered regions. Results We proposed two new predictor models, VSL2-M1 and VSL2-M2, to address this length-dependency problem in prediction of intrinsic protein disorder. These two predictors are similar to the original VSL1 predictor used in the CASP6 experiment. In both models, two specialized predictors were first built and optimized for short (≤30 residues and long disordered regions (>30 residues, respectively. A meta predictor was then trained to integrate the specialized predictors into the final predictor model. As the 10-fold cross-validation results showed, the VSL2 predictors achieved well-balanced prediction accuracies of 81% on both short and long disordered regions. Comparisons over the VSL2 training dataset via 10-fold cross-validation and a blind-test set of unrelated recent PDB chains indicated that VSL2 predictors were significantly more accurate than several existing predictors of intrinsic protein disorder. Conclusion The VSL2 predictors are applicable to disordered regions of any length and can accurately identify the short disordered regions that are often misclassified by our previous disorder predictors. The success of the VSL2 predictors

  3. Length scale and manufacturability in density-based topology optimization

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov; Wang, Fengwen; Sigmund, Ole

    2016-01-01

    Since its original introduction in structural design, density-based topology optimization has been applied to a number of other fields such as microelectromechanical systems, photonics, acoustics and fluid mechanics. The methodology has been well accepted in industrial design processes where it can...... performance and in many cases can completely destroy the optimality of the solution. Therefore, the goal of this paper is to review recent advancements in obtaining manufacturable topology-optimized designs. The focus is on methods for imposing minimum and maximum length scales, and ensuring manufacturable...

  4. Multi length-scale characterisation inorganic materials series

    CERN Document Server

    Bruce, Duncan W; Walton, Richard I

    2013-01-01

    Whereas the first five volumes in the Inorganic Materials Series focused on particular classes of materials (synthesis, structures, chemistry, and properties), it is now very timely to provide complementary volumes that introduce and review state-of-the-art techniques for materials characterization. This is an important way of emphasizing the interplay of chemical synthesis and physical characterization. The methods reviewed include spectroscopic, diffraction, and surface techniques that examine the structure of materials on all length scales, from local atomic structure to long-range crystall

  5. Length and time scales of atmospheric moisture recycling

    NARCIS (Netherlands)

    Van der Ent, R.J.; Savenije, H.H.G.

    2011-01-01

    It is difficult to quantify the degree to which terrestrial evaporation supports the occurrence of precipitation within a certain study region (i.e. regional moisture recycling) due to the scale- and shape-dependence of regional moisture recycling ratios. In this paper we present a novel approach to

  6. Interaction of turbulent length scales with wind turbine blades

    Science.gov (United States)

    Torres-Nieves, Sheilla N.

    Understanding the effects of free-stream turbulence (FST) and surface roughness on the flow around wind turbine blades is imperative in the quest for higher wind turbine efficiency, specially under stall conditions. While many investigations have focused on the aerodynamic loads on wind turbine airfoils, there are no studies that examine the effects of free-stream turbulence and surface roughness on the velocity field around a wind turbine airfoil. Hence, the aim of this investigation is to study the influence of high levels of FST on the flow around smooth and rough surfaces with pressure gradients. Moreover, of great importance in this study is the examination of how the length scales of turbulence and surface roughness interact in the flow over wind turbine airfoils to affect flow separation. Particle Image Velocimetry measurements were performed to analyze the overall flow around a S809 wind turbine blade. Results indicate that when the flow is fully attached, free-stream turbulence significantly decreases aerodynamic efficiency by 82%, yielding to higher loads and fatigue on the blades. On the contrary, when the flow is separated, the effect is reversed and aerodynamic performance is slightly improved (i.e., by 5%) by the presence of the free-stream turbulence. Analysis of the mean flow over the suction surface shows that, under stall conditions, free-stream turbulence delays separation, and surface roughness advances separation. Interestingly, the highly non-linear interaction between free-stream turbulence and surface roughness results in the further advancement of separation. Of particular interest is the study of the region closer to the wall (i.e., the boundary layer), where the flow interacts with both the surface of the blade and the free-stream. Turbulent boundary layer experiments subject to an external favorable pressure gradient (FPG) were performed to study the influence of FST, surface roughness and external pressure gradient (present around the

  7. Cosmogenesis and the origin of the fundamental length scale

    CERN Document Server

    Brout, R; Frère, J M; Gunzig, E; Nardone, P; Truffin, C; Spindel, P

    1980-01-01

    The creation of the universe is regarded as a self-consistent process in which matter is engendered by the space-time varying cosmological gravitational field and vice versa. Abundant production can occur only if the mass of the particles so created is of the order of the Planck mass $(=K^{-1/2})$. We conjecture that this is the origin of the fundamental length scale in field theory, as it is encountered, for example, in present efforts towards grandunification. The region of particle production is steady state in character. It ceases when the produced particles decay. The geometry of this steady state is characteristic of a de Sitter space. It permits one to estimate the number of ordinary particles presently observed, N. We find log N = O (mτ$_{decay}$) = O(g$^{−2}$) = O(10$^2$), with the usual estimate of g = O(10$^{−1}$) at the Planck length scale. This is not inconsistent with the experimental estimate $N \\approx O(10^{90})$. After production, cosmological history gives way to the more conventional ...

  8. Telomere length in alcohol dependence: A role for impulsive choice and childhood maltreatment.

    Science.gov (United States)

    Kang, Jee In; Hwang, Syung Shick; Choi, Jong Rak; Lee, Seung-Tae; Kim, Jieun; Hwang, In Sik; Kim, Hae Won; Kim, Chan-Hyung; Kim, Se Joo

    2017-09-01

    Telomere shortening, a marker of cellular aging, has been considered to be linked with psychosocial stress as well as with chronic alcohol consumption, possibly mediated by oxidative stress and inflammatory response. Recent findings suggested that early life adversity on telomere dynamics may be related to impulsive choice. To further our understanding of the association of impulsive choice and childhood trauma on telomere length, we examined whether delayed discounting and childhood trauma or their interaction is related to leukocyte telomere length, while controlling for multiple potential confounding variables, in patients with alcohol dependence who are considered to have higher impulsive choice and shorter telomere length. We recruited 253 male patients with chronic alcohol dependence. All participants performed the delay discounting task, and the area under curve was used as a measure of delay discounting. Steeper delay discounting represents more impulsive choices. The modified Parent-Child Conflict Tactics Scale was used to measure childhood maltreatment. In addition, confounding factors, including socio-demographic characteristics, the Alcohol Use Disorders Identification Test, the Buss-Perry Aggression Questionnaire, the Resilience Quotient, the Beck Depression Inventory, and the Beck Anxiety Inventory, were also assessed. Hierarchical regression analyses showed a significant main effect of delay discounting (β=0.161, t=2.640, p=0.009), and an interaction effect between delay discounting and childhood maltreatment on leukocyte telomere length (β=0.173, t=2.138, p=0.034). In subsequent analyses stratified by childhood maltreatment, patients with alcohol dependence and high childhood trauma showed a significant relationship between delay discounting and leukocyte telomere length (β=0.279, t=3.183, p=0.002), while those with low trauma showed no association between them. Our findings suggest that higher impulsive choice is associated with shorter telomere

  9. Dynamic Leidenfrost Effect: Relevant Time and Length Scales

    Science.gov (United States)

    Shirota, Minori; van Limbeek, Michiel A. J.; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

    2016-02-01

    When a liquid droplet impacts a hot solid surface, enough vapor may be generated under it to prevent its contact with the solid. The minimum solid temperature for this so-called Leidenfrost effect to occur is termed the Leidenfrost temperature, or the dynamic Leidenfrost temperature when the droplet velocity is non-negligible. We observe the wetting or drying and the levitation dynamics of the droplet impacting on an (isothermal) smooth sapphire surface using high-speed total internal reflection imaging, which enables us to observe the droplet base up to about 100 nm above the substrate surface. By this method we are able to reveal the processes responsible for the transitional regime between the fully wetting and the fully levitated droplet as the solid temperature increases, thus shedding light on the characteristic time and length scales setting the dynamic Leidenfrost temperature for droplet impact on an isothermal substrate.

  10. Concentration and length dependence of DNA looping in transcriptional regulation.

    Directory of Open Access Journals (Sweden)

    Lin Han

    2009-05-01

    Full Text Available In many cases, transcriptional regulation involves the binding of transcription factors at sites on the DNA that are not immediately adjacent to the promoter of interest. This action at a distance is often mediated by the formation of DNA loops: Binding at two or more sites on the DNA results in the formation of a loop, which can bring the transcription factor into the immediate neighborhood of the relevant promoter. These processes are important in settings ranging from the historic bacterial examples (bacterial metabolism and the lytic-lysogeny decision in bacteriophage, to the modern concept of gene regulation to regulatory processes central to pattern formation during development of multicellular organisms. Though there have been a variety of insights into the combinatorial aspects of transcriptional control, the mechanism of DNA looping as an agent of combinatorial control in both prokaryotes and eukaryotes remains unclear. We use single-molecule techniques to dissect DNA looping in the lac operon. In particular, we measure the propensity for DNA looping by the Lac repressor as a function of the concentration of repressor protein and as a function of the distance between repressor binding sites. As with earlier single-molecule studies, we find (at least two distinct looped states and demonstrate that the presence of these two states depends both upon the concentration of repressor protein and the distance between the two repressor binding sites. We find that loops form even at interoperator spacings considerably shorter than the DNA persistence length, without the intervention of any other proteins to prebend the DNA. The concentration measurements also permit us to use a simple statistical mechanical model of DNA loop formation to determine the free energy of DNA looping, or equivalently, the for looping.

  11. Dependence of paracentric inversion rate on tract length

    DEFF Research Database (Denmark)

    York, Thomas L; Durrett, Rick; Nielsen, Rasmus

    2007-01-01

    BACKGROUND: We develop a Bayesian method based on MCMC for estimating the relative rates of pericentric and paracentric inversions from marker data from two species. The method also allows estimation of the distribution of inversion tract lengths. RESULTS: We apply the method to data from...... Drosophila melanogaster and D. yakuba. We find that pericentric inversions occur at a much lower rate compared to paracentric inversions. The average paracentric inversion tract length is approx. 4.8 Mb with small inversions being more frequent than large inversions.If the two breakpoints defining...... a paracentric inversion tract are uniformly and independently distributed over chromosome arms there will be more short tract-length inversions than long; we find an even greater preponderance of short tract lengths than this would predict. Thus there appears to be a correlation between the positions...

  12. Sarcomere length-dependence of activity-dependent twitch potentiation in mouse skeletal muscle

    Directory of Open Access Journals (Sweden)

    MacIntosh Brian R

    2002-12-01

    Full Text Available Abstract Background It has been reported that potentiation of a skeletal muscle twitch response is proportional to muscle length with a negative slope during staircase, and a positive slope during posttetanic potentiation. This study was done to directly compare staircase and posttetanic responses with measurement of sarcomere length to compare their length-dependence. Methods Mouse extensor digitorum longus (EDL muscles were dissected to small bundles of fibers, which permit measurement of sarcomere length (SL, by laser diffraction. In vitro fixed-end contractions of EDL fiber bundles were elicited at 22°C and 35°C at sarcomere lengths ranging from 2.35 μm to 3.85 μm. Twitch contractions were assessed before and after 1.5 s of 75 Hz stimulation at 22°C or during 10 s of 10 Hz stimulation at 22°C or 35°C. Results Staircase potentiation was greater at 35°C than 22°C, and the relative magnitude of the twitch contraction (Pt*/Pt was proportional to sarcomere length with a negative slope, over the range 2.3 μm – 3.7 μm. Linear regression yielded the following: Pt*/Pt = -0.59·SL+3.27 (r2 = 0.74; Pt*/Pt = -0.39·SL+2.34 (r2 = 0.48; and Pt*/Pt = -0.50·SL+2.45 (r2 = 0.80 for staircase at 35°C, and 22°C and posttetanic response respectively. Posttetanic depression rather than potentiation was present at long SL. This indicates that there may be two processes operating in these muscles to modulate the force: one that enhances and a second that depresses the force. Either or both of these processes may have a length-dependence of its mechanism. Conclusion There is no evidence that posttetanic potentiation is fundamentally different from staircase in these muscles.

  13. Scale dependent inference in landscape genetics

    Science.gov (United States)

    Samuel A. Cushman; Erin L. Landguth

    2010-01-01

    Ecological relationships between patterns and processes are highly scale dependent. This paper reports the first formal exploration of how changing scale of research away from the scale of the processes governing gene flow affects the results of landscape genetic analysis. We used an individual-based, spatially explicit simulation model to generate patterns of genetic...

  14. Lee-Yang-inspired functional with a density-dependent neutron-neutron scattering length

    Science.gov (United States)

    Grasso, M.; Lacroix, D.; Yang, C. J.

    2017-05-01

    Inspired by the low-density Lee-Yang expansion for the energy of a dilute Fermi gas of density ρ and momentum kF, we introduce here a Skyrme-type functional that contains only s -wave terms and provides, at the mean-field level, (i) a satisfactory equation of state for neutron matter from extremely low densities up to densities close to the equilibrium point, and (ii) a good-quality equation of state for symmetric matter at density scales around the saturation point. This is achieved by using a density-dependent neutron-neutron scattering length a (ρ ) which satisfies the low-density limit (for Fermi momenta going to zero) and has a density dependence tuned in such a way that the low-density constraint |a (ρ ) kF|≤1 is satisfied at all density scales.

  15. Length of winter coat in horses depending on husbandry conditions.

    Science.gov (United States)

    Bocian, Krzysztof; Strzelec, Katarzyna; Janczarek, Iwona; Jabłecki, Zygmunt; Kolstrung, Ryszard

    2017-02-01

    This paper analyzes changes in the length of coat on selected body areas in horses and ponies kept under different husbandry (stable) conditions during the winter-spring period. The study included 12 Małpolski geldings and 12 geldings of Felin ponies aged 10-15 years. Horses were kept in two stables (six horses and six ponies in each stable). The type of performance, husbandry conditions and feeding of the studied animals were comparable. As of December 1, samples of hair coat from the scapula, sternum, back and abdomen areas of both body sides were collected seven times. The lengths of 20 randomly selected hair fibers were measured. Daily measurements of air temperature in the stables were also taken. An analysis of variance (ANOVA) was performed using the following factors: the body part from where the coat was sampled, the subsequent examination and the stable as well as the interaction between these factors. The significance of differences between means was determined with a t-Tukey test. The relations between air temperature in the stable and hair length were calculated using Pearson's correlation. It was found that air temperature in the stable impacts the length of winter coat in horses and ponies. The effect of this factor is more pronounced in ponies; as in the stables with lower temperatures it produces a longer hair coat which is more evenly distributed over the body in comparison with horses. Keeping horses and ponies in stables with a low air temperature accelerates coat shedding by approximately 25 days. Coat shedding begins from the scapula area. © 2016 Japanese Society of Animal Science.

  16. Oligonucleotide length dependent formation of virus-like particles.

    Science.gov (United States)

    Maassen, Stan J; de Ruiter, Mark Vincent; Lindhoud, Saskia; Cornelissen, Jeroen J L M

    2018-03-08

    Understanding the assembly pathway of viruses can contribute to creating monodisperse virus-based materials. In this study the Cowpea Chlorotic Mottle Virus is used to determine the interactions between the capsid proteins of viruses and their cargo. The assembly of the capsid proteins in the presence of different lengths of short single-stranded DNA is studied at neutral pH, where the protein-protein interactions are weak. Chromatography, electrophoresis, microscopy, and light scattering shows that the assembly efficiency and speed of the particles increases with increasing length of oligonucleotides. The minimal length required for assembly at the conditions used here is shown to be 14 nucleotides. Assembly of particles containing such short strands of ssDNA can take almost a month. This slow assembly process enabled the study of intermediate states, confirming a low cooperative assembly for CCMV and allows for further expansion of current assembly theories. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Scale dependence of acoustic velocities. An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Gotusso, Angelamaria Pillitteri

    2001-06-01

    Reservoir and overburden data (e.g. seismic, sonic log and core data) are collected at different stages of field development, at different scales, and under different measurement conditions. A more precise reservoir characterization could be obtained by combining all the collected data. Reliable data may also be obtained from drill cuttings. This methodology can give data in quasi-real time, it is easily applicable, and cheap. It is then important, to understand the relationship between results obtained from measurements at different scales. In this Thesis acoustic velocities measured at several different laboratory scales are presented. This experimental study was made in order to give the base for the development of a model aiming to use/combine appropriately the data collected at different scales. The two main aspects analyzed are the experimental limitations due to the decrease in sample size and the significance of measurements in relation to material heterogeneities. Plexiglas, an isotropic, non-dispersive artificial material, with no expected scale effect, was used to evaluate the robustness of the measurement techniques. The results emphasize the importance of the wavelength used with respect to the sample length. If the sample length (L) is at least 5 time bigger than wavelength used ({lambda}), then the measured velocities do not depend on sample size. Leca stone, an artificial isotropic material containing spherical grains was used to evaluate the combined effects of technique, heterogeneities and sample length. The ratio between the scale of the heterogeneities and the sample length has to be taken in to account. In this case velocities increase with decreasing sample length when the ratio L/{lambda} is smaller than 10-15 and at the same time the ratio between sample length and grain size is greater than 10. Measurements on natural rocks demonstrate additional influence of grain mineralogy, shape and orientation. Firenzuola sandstone shows scale and

  18. Non-perturbative gravity at different length scales

    International Nuclear Information System (INIS)

    Folkerts, Sarah

    2013-01-01

    problem. Since the axion is the (pseudo-) Goldstone boson of a broken U(1) global symmetry, quantum gravitational global symmetry violations could reinstate the CP problem even in the presence of the axion. We show that in the presence of massless neutrinos possible conflicts with the axion solution can be resolved. Demanding a viable axion solution of the strong CP problem, we derive new bounds on neutrino masses. In addition, we investigate the QCD vacuum energy screening mechanism for light quarks. It is well-known that the θ-dependence of the QCD vacuum vanishes linearly with the lightest quark mass. By an analogy with Schwinger pair creation in a strong electric field, we consider vacuum screening by η' bubble nucleation. We find that using the standard instanton approximation for the η' potential, the linear dependence is not recovered. We take this as an indication for the non-analyticity of the QCD vacuum energy proposed by Witten. In the last part of this thesis, we are concerned with gravitational effects on cosmological scales. The recent Planck data indicate that one of the best motivated dark matter candidates, the axion, is in conflict with bounds on isocurvature perturbations. We show that the isocurvature fluctuations can be efficiently suppressed when introducing a non-minimal kinetic coupling for the axion field during inflation. Thus, the axion can be a viable dark matter candidate for a large range of parameters. We show that the same coupling allows for the Standard Model Higgs to drive inflation and the dark matter density to be produced by the axion. Gravitational effects on large scales would also be sensitive to a possible mass for the graviton. However, such a modification has been known to be plagued by inconsistencies. In light of the recent proposal of a ghost-free theory of massive gravity by de Rham, Gabadadze and Tolley, we investigate the cubic order interactions of this theory in terms of helicities of a massive spin-2

  19. Non-perturbative gravity at different length scales

    Energy Technology Data Exchange (ETDEWEB)

    Folkerts, Sarah

    2013-12-18

    problem. Since the axion is the (pseudo-) Goldstone boson of a broken U(1) global symmetry, quantum gravitational global symmetry violations could reinstate the CP problem even in the presence of the axion. We show that in the presence of massless neutrinos possible conflicts with the axion solution can be resolved. Demanding a viable axion solution of the strong CP problem, we derive new bounds on neutrino masses. In addition, we investigate the QCD vacuum energy screening mechanism for light quarks. It is well-known that the θ-dependence of the QCD vacuum vanishes linearly with the lightest quark mass. By an analogy with Schwinger pair creation in a strong electric field, we consider vacuum screening by η' bubble nucleation. We find that using the standard instanton approximation for the η' potential, the linear dependence is not recovered. We take this as an indication for the non-analyticity of the QCD vacuum energy proposed by Witten. In the last part of this thesis, we are concerned with gravitational effects on cosmological scales. The recent Planck data indicate that one of the best motivated dark matter candidates, the axion, is in conflict with bounds on isocurvature perturbations. We show that the isocurvature fluctuations can be efficiently suppressed when introducing a non-minimal kinetic coupling for the axion field during inflation. Thus, the axion can be a viable dark matter candidate for a large range of parameters. We show that the same coupling allows for the Standard Model Higgs to drive inflation and the dark matter density to be produced by the axion. Gravitational effects on large scales would also be sensitive to a possible mass for the graviton. However, such a modification has been known to be plagued by inconsistencies. In light of the recent proposal of a ghost-free theory of massive gravity by de Rham, Gabadadze and Tolley, we investigate the cubic order interactions of this theory in terms of helicities of a massive spin-2

  20. Length scales for the Navier-Stokes equations on a rotating sphere

    International Nuclear Information System (INIS)

    Kyrychko, Yuliya N.; Bartuccelli, Michele V.

    2004-01-01

    In this Letter we obtain the dissipative length scale for the Navier-Stokes equations on a two-dimensional rotating sphere S 2 . This system is a fundamental model of the large scale atmospheric dynamics. Using the equations of motion in their vorticity form, we construct the ladder inequalities from which a set of time-averaged length scales is obtained

  1. Determination of length scale effects in nonlocal media

    NARCIS (Netherlands)

    Simone, A; Iacono, C; Sluys, LJ; Yao, ZH; Yuan, MW; Zhong, WX

    2004-01-01

    A combined continuous-discontinuous framework for failure is presented. Continuous failure is described with a gradient enhanced damage model and discontinuous failure is introduced by adding discontinuities to finite elements through a node-based enhancement. The continuous model contains a length

  2. On the length-scale of the wind profile

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Gryning, Sven-Erik; Mann, Jakob

    2010-01-01

    We present the results of an analysis of simultaneous sonic anemometer observations of wind speed and velocity spectra over flat and homogeneous terrain from 10 up to 160 m height performed at the National Test Station for Wind Turbines at Høvsøre, Denmark. The mixing length, l, derived from the ...

  3. Reconciling the Reynolds number dependence of scalar roughness length and laminar resistance

    Science.gov (United States)

    Li, Dan; Rigden, Angela; Salvucci, Guido; Liu, Heping

    2017-04-01

    The scalar roughness length and laminar resistance are necessary for computing scalar fluxes in numerical simulations and experimental studies. Their dependence on flow properties such as the Reynolds number remains controversial. In particular, two important power laws ("1/4" and "1/2"), both having strong theoretical foundations, have been widely used in various parameterizations and models. Building on a previously proposed phenomenological model for interactions between the viscous sublayer and the turbulent flow, it is shown here that the two scaling laws can be reconciled. The 1/4 power law corresponds to the situation where the vertical diffusion is balanced by the temporal change or advection due to a constant velocity in the viscous sublayer, while the 1/2 scaling corresponds to the situation where the vertical diffusion is balanced by the advection due to a linear velocity profile in the viscous sublayer. In addition, the recently proposed "1" power law scaling is also recovered, which corresponds to the situation where molecular diffusion dominates the scalar budget in the viscous sublayer. The formulation proposed here provides a unified framework for understanding the onset of these different scaling laws and offers a new perspective on how to evaluate them experimentally.

  4. Reconciling the Reynolds number dependence of scalar roughness length and laminar resistance

    Science.gov (United States)

    Li, D.; Rigden, A. J.; Salvucci, G.; Liu, H.

    2017-12-01

    The scalar roughness length and laminar resistance are necessary for computing scalar fluxes in numerical simulations and experimental studies. Their dependence on flow properties such as the Reynolds number remains controversial. In particular, two important power laws (1/4 and 1/2), proposed by Brutsaert and Zilitinkevich, respectively, are commonly seen in various parameterizations and models. Building on a previously proposed phenomenological model for interactions between the viscous sublayer and the turbulent flow, it is shown here that the two scaling laws can be reconciled. The "1/4" power law corresponds to the situation where the vertical diffusion is balanced by the temporal change or advection due to a constant velocity in the viscous sublayer, while the "1/2" power law scaling corresponds to the situation where the vertical diffusion is balanced by the advection due to a linear velocity profile in the viscous sublayer. In addition, the recently proposed "1" power law scaling is also recovered, which corresponds to the situation where molecular diffusion dominates the scalar budget in the viscous sublayer. The formulation proposed here provides a unified framework for understanding the onset of these different scaling laws and offers a new perspective on how to evaluate them experimentally.

  5. SQUID magnetometry from nanometer to centimeter length scales

    International Nuclear Information System (INIS)

    Hatridge, Michael J.

    2010-01-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  6. SQUID magnetometry from nanometer to centimeter length scales

    Energy Technology Data Exchange (ETDEWEB)

    Hatridge, Michael J. [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    The development of Superconducting QUantum Interference Device (SQUID)-based magnetometer for two applications, in vivo prepolarized, ultra-low field MRI of humans and dispersive readout of SQUIDs for micro- and nano-scale magnetometery, are the focus of this thesis.

  7. Influence of the course boundary value problem on length scale parmeters for second-gradient continuum theories

    Energy Technology Data Exchange (ETDEWEB)

    Luscher, Darby J [Los Alamos National Laboratory; Bronkhorst, Curt A [Los Alamos National Laboratory; Mc Dowell, David L [GEORGIA TECH

    2010-12-20

    All nonlocal continuum descriptions of inelastic material response involve length scale parameters that either directly or implicitly quantify the physical dimensions of a neighborhood of response which influences the behavior at a particular point. The second-gradient continuum theories such as those developed by Germain, Toupin and Mindlin, and Eringen, and giving rise to strain-gradient plasticity, is becoming a common coarse-scale basis for homogenization of material response that respects the non local nature of heterogeneous material response. Ideally, the length scale parameters involved in such homogenization would be intrinsically associated with dominant aspects of the microstructure. However, these parameters, at least in some cases, are inextricably linked to the details of the coarse scale boundary value problem. Accordingly, they cannot be viewed as pure constitutive parameters. An example problem of multiscale homogenization is presented to underscore the dependence of second-gradient length scale parameters on the coarse scale boundary value problem, namely the multiscale response of an idealized porous microstructure. The fine scale (microstructure) comprises elastic perfectly plastic matrix with a periodic array of circular voids. This fine scale description of the problem is identical for two separate classes of coarse scale boundary value problem, viz. an extruded channel subject to compression and eventually developing plastic shear bands and a thin layer of material with larger (coarse scale) elliptical voids subject to shear deformation. Implications of the relationship between length scale parameters and the details of the coarse scale boundary value problem are discussed and ideas to ascertain such length parameters from evolving response fields are presented.

  8. Determination of Longitudinal Electron Bunch Lengths on Picosecond Time Scales

    CERN Document Server

    Martínez, C; Calviño, F

    1999-01-01

    At CERN (European Laboratory for Particle Physics) the CLIC (Compact Linear Collider) study is pursuing the design of an electron-positron high-energy linear collider using an innovative concept for the RF (Radio Frequency) power production, the socalled two-beam acceleration scheme. In order to keep the length of the collider in a reasonable range while being able of accelerating electrons and positrons up to 5 TeV, the normal-conducting accelerating structures should operate at very high frequency (in this case 30 GHz). The RF power necessary to feed the accelerating cavities is provided by a second electron beam, the drive beam, running parallel to the main beam. The CLIC Test Facility (CTF) was build with the main aim of studying and demonstrating the feasibility of the two beam acceleration scheme and technology. It is composed of two beams, the drive beam that will generate the 30 GHz RF power and the main beam which will be accelerated by this power. In order to have a good efficiency for the power gen...

  9. Displacement-length scaling of brittle faults in ductile shear.

    Science.gov (United States)

    Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

    2011-11-01

    Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement-distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow.

  10. Displacement–length scaling of brittle faults in ductile shear

    Science.gov (United States)

    Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

    2011-01-01

    Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement–distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow. PMID:26806996

  11. Exploiting scale dependence in cosmological averaging

    International Nuclear Information System (INIS)

    Mattsson, Teppo; Ronkainen, Maria

    2008-01-01

    We study the role of scale dependence in the Buchert averaging method, using the flat Lemaitre–Tolman–Bondi model as a testing ground. Within this model, a single averaging scale gives predictions that are too coarse, but by replacing it with the distance of the objects R(z) for each redshift z, we find an O(1%) precision at z<2 in the averaged luminosity and angular diameter distances compared to their exact expressions. At low redshifts, we show the improvement for generic inhomogeneity profiles, and our numerical computations further verify it up to redshifts z∼2. At higher redshifts, the method breaks down due to its inability to capture the time evolution of the inhomogeneities. We also demonstrate that the running smoothing scale R(z) can mimic acceleration, suggesting that it could be at least as important as the backreaction in explaining dark energy as an inhomogeneity induced illusion

  12. Origin of the second length scale found above TN in UO2

    International Nuclear Information System (INIS)

    Watson, G.M.; Gaulin, B.D.; Gibbs, D.; Thurston, T.R.; Simpson, P.J.; Shapiro, S.M.; Lander, G.H.; Matzke, H.; Wang, S.; Dudley, M.

    1996-01-01

    We present the results of x-ray- and neutron-scattering studies of the temperature dependence of the magnetic scattering exhibited by the type-I, triple-Q antiferromagnet UO 2 . Our neutron-scattering results are consistent with those of earlier studies, including the observation of short-ranged magnetic correlations at temperatures near and above T N . However, it is found by x-ray diffraction that a second, longer length scale is induced near T N when the near-surface volume of the sample is mechanically roughened. The longitudinal and transverse widths of the additional scattering increase continuously with increasing temperature above T N , similar to that which has been observed near the magnetic ordering transitions of Ho, Tb, and NpAs and near the tetragonal-to-cubic transitions of various perovskites. Another unusual feature of the present results for UO 2 involves the apparent shift with temperature of the magnetic scattering along the surface normal direction at the (1,1,0) reflection, but not at the (2,1,0) reflection. To our knowledge, this is the first observation of a second length scale near a first-order transition. copyright 1996 The American Physical Society

  13. Comparison of the Effects of the Different Methods for Computing the Slope Length Factor at a Watershed Scale

    Directory of Open Access Journals (Sweden)

    Fu Suhua

    2013-09-01

    Full Text Available The slope length factor is one of the parameters of the Universal Soil Loss Equation (USLE and the Revised Universal Soil Loss Equation (RUSLE and is sometimes calculated based on a digital elevation model (DEM. The methods for calculating the slope length factor are important because the values obtained may depend on the methods used for calculation. The purpose of this study was to compare the difference in spatial distribution of the slope length factor between the different methods at a watershed scale. One method used the uniform slope length factor equation (USLFE where the effects of slope irregularities (such as slope gradient, etc. on soil erosion by water were not considered. The other method used segmented slope length factor equation(SSLFE which considered the effects of slope irregularities on soil erosion by water. The Arc Macro Language (AML Version 4 program for the revised universal soil loss equation(RUSLE.which uses the USLFE, was chosen to calculate the slope length factor. In a parallel analysis, the AML code of RUSLE Version 4 was modified according to the SSLFE to calculate the slope length factor. Two watersheds with different slope and gully densities were chosen. The results show that the slope length factor and soil loss using the USLFE method were lower than those using the SSLFE method, especially on downslopes watershed with more frequent steep slopes and higher gully densities. In addition, the slope length factor and soil loss calculated by the USLFE showed less spatial variation.

  14. Comparison of relativity theories with observer-independent scales of both velocity and length/mass

    International Nuclear Information System (INIS)

    Amelino-Camelia, Giovanni; Benedetti, Dario; D'Andrea, Francesco; Procaccini, Andrea

    2003-01-01

    We consider the two most studied proposals of relativity theories with observer-independent scales of both velocity and length/mass: the one discussed by Amelino-Camelia as an illustrative example for the original proposal (Preprint gr-qc/0012051) of theories with two relativistic invariants, and an alternative more recently proposed by Magueijo and Smolin (Preprint hep-th/0112090). We show that these two relativistic theories are much more closely connected than it would appear on the basis of a naive analysis of their original formulations. In particular, in spite of adopting a rather different formal description of the deformed boost generators, they end up assigning the same dependence of momentum on rapidity, which can be described as the core feature of these relativistic theories. We show that this observation can be used to clarify the concepts of particle mass, particle velocity and energy-momentum conservation rules in these theories with two relativistic invariants

  15. In Situ Observation of Strain Evolution in Cp-Ti Over Multiple Length Scales

    Science.gov (United States)

    Bettles, C. J.; Lynch, P. A.; Stevenson, A. W.; Tomus, D.; Gibson, M. A.; Wallwork, K.; Kimpton, J.

    2011-01-01

    The strain evolution in polycrystalline CP-Ti strip under tension was studied in situ and at two length scales using Synchrotron X-ray diffraction. To establish the bulk material behavior, experiments were performed at the Australian Synchrotron facility. Because of the relatively large grain size, discontinuous "spotty" Debye ring patterns were observed, and a peak fitting algorithm was developed to determine the individual spot positions with the necessary precision for strain determination. The crystallographic directional dependence of strain anisotropy during the loading cycle was determined. Strain anisotropy and yielding of individual crystallographic planes prior to the macroscopic yield point were further clarified by in situ loading experiments performed at the Advanced Light Source (ALS). The deviatoric strain accumulation and plastic response were mapped on a grain-by-grain basis. The onset of microscopic yielding in the grains was identified and correlated with the relative orientation of the grains with respect to the loading direction.

  16. Length dependence of rectification in organic co-oligomer spin rectifiers

    International Nuclear Information System (INIS)

    Hu Gui-Chao; Zhang Zhao; Li Ying; Ren Jun-Feng; Wang Chuan-Kui

    2016-01-01

    The rectification ratio of organic magnetic co-oligomer diodes is investigated theoretically by changing the molecular length. The results reveal two distinct length dependences of the rectification ratio: for a short molecular diode, the charge-current rectification changes little with the increase of molecular length, while the spin-current rectification is weakened sharply by the length; for a long molecular diode, both the charge-current and spin-current rectification ratios increase quickly with the length. The two kinds of dependence switch at a specific length accompanied with an inversion of the rectifying direction. The molecular ortibals and spin-resolved transmission analysis indicate that the dominant mechanism of rectification suffers a change at this specific length, that is, from asymmetric shift of molecular eigenlevels to asymmetric spatial localization of wave functions upon the reversal of bias. This work demonstrates a feasible way to control the rectification in organic co-oligomer spin diodes by adjusting the molecular length. (paper)

  17. Kelvin Absolute Temperature Scale Identified as Length Scale and Related to de Broglie Thermal Wavelength

    Science.gov (United States)

    Sohrab, Siavash

    Thermodynamic equilibrium between matter and radiation leads to de Broglie wavelength λdβ = h /mβvrβ and frequency νdβ = k /mβvrβ of matter waves and stochastic definitions of Planck h =hk =mk c and Boltzmann k =kk =mk c constants, λrkνrk = c , that respectively relate to spatial (λ) and temporal (ν) aspects of vacuum fluctuations. Photon massmk =√{ hk /c3 } , amu =√{ hkc } = 1 /No , and universal gas constant Ro =No k =√{ k / hc } result in internal Uk = Nhνrk = Nmkc2 = 3 Nmkvmpk2 = 3 NkT and potential pV = uN\\vcirc / 3 = N\\ucirc / 3 = NkT energy of photon gas in Casimir vacuum such that H = TS = 4 NkT . Therefore, Kelvin absolute thermodynamic temperature scale [degree K] is identified as length scale [meter] and related to most probable wavelength and de Broglie thermal wavelength as Tβ =λmpβ =λdβ / 3 . Parallel to Wien displacement law obtained from Planck distribution, the displacement law λwS T =c2 /√{ 3} is obtained from Maxwell -Boltzmann distribution of speed of ``photon clusters''. The propagation speeds of sound waves in ideal gas versus light waves in photon gas are described in terms of vrβ in harmony with perceptions of Huygens. Newton formula for speed of long waves in canals √{ p / ρ } is modified to √{ gh } =√{ γp / ρ } in accordance with adiabatic theory of Laplace.

  18. Morphology Characterization of PP/Clay Nanocomposites Across the Length Scales of the Structural Architecture

    NARCIS (Netherlands)

    Szazdi, Laszlo; Abranyi, Agnes; Pukansky Jr, Bela; Vancso, Gyula J.; Pukanszky, B.; Pukanszky, Bela

    2006-01-01

    The structure and rheological properties of a large number of layered silicate poly(propylene) nanocomposites were studied with widely varying compositions. Morphology characterization at different length scales was achieved by SEM, TEM, and XRD. Rheological measurements supplied additional

  19. Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members

    Science.gov (United States)

    Caro, L. A.; Martí-Vargas, J. R.; Serna, P.

    2013-11-01

    For design purposes, it is generally considered that prestressing strand transfer length does not change with time. However, some experimental studies on the effect of time on transfer lengths show contradictory results. In this paper, an experimental research to study transfer length changes over time is presented. A test procedure based on the ECADA testing technique to measure prestressing strand force variation over time in pretensioned prestressed concrete specimens has been set up. With this test method, an experimental program that varies concrete strength, specimen cross section, age of release, prestress transfer method, and embedment length has been carried out. Both the initial and long-term transfer lengths of 13-mm prestressing steel strands have been measured. The test results show that transfer length variation exists for some prestressing load conditions, resulting in increased transfer length over time. The applied test method based on prestressing strand force measurements has shown more reliable results than procedures based on measuring free end slips and longitudinal strains of concrete. An additional factor for transfer length models is proposed in order to include the time-dependent evolution of strand transfer length in pretensioned prestressed concrete members.

  20. Estimating the minimum delay optimal cycle length based on a time-dependent delay formula

    Directory of Open Access Journals (Sweden)

    Ahmed Y. Zakariya

    2016-09-01

    Full Text Available For fixed time traffic signal control, the well-known Webster’s formula is widely used to estimate the minimum delay optimal cycle length. However, this formula overestimates the cycle length for high degrees of saturation. In this paper, we propose two regression formulas for estimating the minimum delay optimal cycle length based on a time-dependent delay formula as used in the Canadian Capacity Guide and the Highway Capacity Manual (HCM. For this purpose, we develop a search algorithm to determine the minimum delay optimal cycle length required for the regression analysis. Numerical results show that the proposed formulas give a better estimation for the optimal cycle length at high intersection flow ratios compared to Webster’s formula.

  1. Controlling the optical path length in turbid media using differential path-length spectroscopy: fiber diameter dependence

    NARCIS (Netherlands)

    Kaspers, O. P.; Sterenborg, H. J. C. M.; Amelink, A.

    2008-01-01

    We have characterized the path length for the differential path-length spectroscopy (DPS) fiber optic geometry for a wide range of optical properties and for fiber diameters ranging from 200 mu m to 1000 mu m. Phantom measurements show that the path length is nearly constant for scattering

  2. Flame Treatment of Low-Density Polyethylene: Surface Chemistry Across the Length Scale

    NARCIS (Netherlands)

    Song, Jing; Gunst, Ullrich; Arlinghaus, Heinrich F.; Vancso, Gyula J.

    2007-01-01

    The relationship between surface chemistry and morphology of flame treated low-density polyethylene (LDPE) was studied by various characterization techniques across different length scales. The chemical composition of the surface was determined on the micrometer scale by X-ray photoelectron

  3. The PVC technique a method to estimate the dissipation length scale in turbulent flows

    Science.gov (United States)

    Ho, Chih-Ming; Zohar, Yitshak

    1997-12-01

    A time-averaged length scale can be defined by a pair of successive turbulent-velocity derivatives, i.e. [dnu(x)/ dxn][prime prime or minute]/ [dn+1u(x)/ dxn+1][prime prime or minute]. The length scale associated with the zeroth- and the first-order derivatives, u[prime prime or minute]/u[prime prime or minute]x, is the Taylor microscale. In isotropic turbulence, this scale is the average length between zero crossings of the velocity signal. The average length between zero crossings of the first velocity derivative, i.e. u[prime prime or minute]x/u[prime prime or minute]xx, can be reliably obtained by using the peak-valley-counting (PVC) technique. We have found that the most probable scale, rather than the average, equals the wavelength at the peak of the dissipation spectrum in a plane mixing layer (Zohar & Ho 1996). In this study, we experimentally investigate the generality of applying the PVC technique to estimate the dissipation scale in three basic turbulent shear flows: a flat-plate boundary layer, a wake behind a two-dimensional cylinder and a plane mixing layer. We also analytically explore the quantitative relationships among this length scale and the Kolmogorov and Taylor microscales.

  4. Fourier transform analysis of rabbit detrusor autonomous contractions reveals length dependent increases in tone and slow wave development at long lengths.

    Science.gov (United States)

    Byrne, Michael D; Klausner, Adam P; Speich, John E; Southern, Jordan B; Habibi, Joseph R; Ratz, Paul H

    2013-07-01

    Bladder wall muscle (detrusor) develops low amplitude rhythmic contractions. Low amplitude rhythmic contraction activity is increased in detrusor from patients with overactive bladder. In this in vitro study we used fast Fourier transforms to assess the length dependence of low amplitude rhythmic contraction components. Rabbit detrusor strips were placed in a muscle bath between 2 clips to adjust length and record isometric tension. Tissues stretched from 70% to 130% of a reference muscle length at 10% increments were allowed to develop low amplitude rhythmic contractions at each length for 20 minutes. Low amplitude rhythmic contraction data were analyzed using fast Fourier transforms and represented by a frequency rather than a time spectrum. Based on fast Fourier transform analysis summarized by signal peaks within specific frequency ranges, rabbit low amplitude rhythmic contraction waveforms were divided into 1 tonic and 2 phasic components, defined as A0 + A1F1 + A2F2, where A0 is a length dependent basal tonic component that increases linearly, A1F1 is a slow wave with a length dependent specific amplitude (A1) and a length independent constant frequency (F1) of approximately 11.2 Hz, and A2F2 is a fast wave with a length dependent amplitude (A2) and frequency (F2) of approximately 0.03 Hz. Fast Fourier transform analysis revealed that rabbit low amplitude rhythmic contractions consist of a basal tonic component plus 2 phasic components. The amplitude of all 3 components was length dependent. The frequency of the fast component was not length dependent and the slow component was absent at short muscle lengths, developing only at muscle lengths beyond that producing a maximum active contraction. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  5. Relevant time- and length scale of touch-down for drops impacting on a heated surface

    Science.gov (United States)

    van Limbeek, Michiel A. J.; Shirota, Minori; Sun, Chao; Prosperetti, Andrea; Lohse, Detlef

    2015-11-01

    The vapor generated from a liquid drop impacting a hot solid surface can prevent it to make contact, depending on the solid temperature. The minimum temperature when no contact is made between the drop and the solid is called the dynamic Leidenfrost temperature. The latent heat needed to generated the vapor is drawn from the solid, and in general the Leidenfrost temperature depends on the solid thermal properties. Here we show experiments conducted on a sapphire plate, to minimize the cooling of the solid and ensuring nearly isothermal conditions. By using high speed total internal reflection imaging, we observe the drop base during impact up to about 100nm above the substrate surface. By this technique we are able to study the processes responsible for the transition between fully wetting and fully levitating drop impact conditions as the solid temperature increases. We reveal the relevant length- and time-scales for the dimple formation under the drop and explain their relevance for the late-time dynamics. As the transition regime is traversed from low to high temperature, the liquid-solid contact gradually decreases which reduces the friction with the solid, enhancing the spreading of the drop considerably.

  6. Genetic markers associated with abstinence length in alcohol-dependent subjects treated with acamprosate

    OpenAIRE

    Karpyak, V M; Biernacka, J M; Geske, J R; Jenkins, G D; Cunningham, J M; R?egg, J; Kononenko, O; Leontovich, A A; Abulseoud, O A; Hall-Flavin, D K; Loukianova, L L; Schneekloth, T D; Skime, M K; Frank, J; N?then, M M

    2014-01-01

    Acamprosate supports abstinence in some alcohol-dependent subjects, yet predictors of response are unknown. To identify response biomarkers, we investigated associations of abstinence length with polymorphisms in candidate genes in glycine and glutamate neurotransmission pathways and genes previously implicated in acamprosate response. Association analyses were conducted in the discovery sample of 225 alcohol-dependent subjects treated with acamprosate for 3 months in community-based treatmen...

  7. Adiabatic dynamics of periodic waves in Bose-Einstein condensates with time dependent atomic scattering length

    International Nuclear Information System (INIS)

    Abdullaev, F.Kh.; Kamchatnov, A.M.; Konotop, V.V.; Brazhnyi, V.A.

    2003-01-01

    Evolution of periodic matter waves in one-dimensional Bose-Einstein condensates with time-dependent scattering length is described. It is shown that variation of the effective nonlinearity is a powerful tool for controlled generation of bright and dark solitons starting with periodic waves

  8. Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

    NARCIS (Netherlands)

    Fiscaletti, D.; Elsinga, G.E.; Attili, A; Bisetti, F; Buxton, O.R.H.

    2016-01-01

    The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor ei, with the vorticity vector ω, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and

  9. Scaling of localization length of a quasi 1D system with longitudinal boundary roughness

    International Nuclear Information System (INIS)

    Abhijit Kar Gupta; Sen, A.K.

    1994-08-01

    We introduce irregularities on one of the longitudinal boundaries of a quasi 1D strip which has no bulk disorder. We calculate the localization length of such a system within the scope of tight-binding formalism and see how it behaves with the roughness introduced on the boundary and with the strip-width. We find that localization length scales with a composite one parameter. (author). 6 refs, 4 figs

  10. CHANG-ES. IX. Radio scale heights and scale lengths of a consistent sample of 13 spiral galaxies seen edge-on and their correlations

    Science.gov (United States)

    Krause, Marita; Irwin, Judith; Wiegert, Theresa; Miskolczi, Arpad; Damas-Segovia, Ancor; Beck, Rainer; Li, Jiang-Tao; Heald, George; Müller, Peter; Stein, Yelena; Rand, Richard J.; Heesen, Volker; Walterbos, Rene A. M.; Dettmar, Ralf-Jürgen; Vargas, Carlos J.; English, Jayanne; Murphy, Eric J.

    2018-03-01

    Aim. The vertical halo scale height is a crucial parameter to understand the transport of cosmic-ray electrons (CRE) and their energy loss mechanisms in spiral galaxies. Until now, the radio scale height could only be determined for a few edge-on galaxies because of missing sensitivity at high resolution. Methods: We developed a sophisticated method for the scale height determination of edge-on galaxies. With this we determined the scale heights and radial scale lengths for a sample of 13 galaxies from the CHANG-ES radio continuum survey in two frequency bands. Results: The sample average values for the radio scale heights of the halo are 1.1 ± 0.3 kpc in C-band and 1.4 ± 0.7 kpc in L-band. From the frequency dependence analysis of the halo scale heights we found that the wind velocities (estimated using the adiabatic loss time) are above the escape velocity. We found that the halo scale heights increase linearly with the radio diameters. In order to exclude the diameter dependence, we defined a normalized scale height h˜ which is quite similar for all sample galaxies at both frequency bands and does not depend on the star formation rate or the magnetic field strength. However, h˜ shows a tight anticorrelation with the mass surface density. Conclusions: The sample galaxies with smaller scale lengths are more spherical in the radio emission, while those with larger scale lengths are flatter. The radio scale height depends mainly on the radio diameter of the galaxy. The sample galaxies are consistent with an escape-dominated radio halo with convective cosmic ray propagation, indicating that galactic winds are a widespread phenomenon in spiral galaxies. While a higher star formation rate or star formation surface density does not lead to a higher wind velocity, we found for the first time observational evidence of a gravitational deceleration of CRE outflow, e.g. a lowering of the wind velocity from the galactic disk.

  11. Microstructural characterization of transformable Fe-Mn alloys at different length scales

    International Nuclear Information System (INIS)

    Liang, X.; Wang, X.; Zurob, H.S.

    2009-01-01

    The as-annealed and deformed Microstructure of transformable Fe-Mn alloys were, comprehensively, characterized over a wide range of length scales. Differential interference contrast optical metallography, combined with a tinting etching method, was employed to examine the grain morphology. A new specimen preparation method, involving electro-polishing and electro-etching, was developed for scanning electron microscopy and electron back-scattered diffraction analysis. This method leads to a very good imaging contrast and thus bridges the length scale gap between optical metallography and transmission electron microscopy. Moreover, it enables simultaneous scanning electron microscopy and electron backscatter diffraction analysis which allows correlations among morphology, crystal orientation and phase analysis in the length scale of microns. Transmission electron microscopy investigations were also made to evaluate the thermal and mechanical transformation products as well as defect structures.

  12. Is the permeability of naturally fractured rocks scale dependent?

    Science.gov (United States)

    Azizmohammadi, Siroos; Matthäi, Stephan K.

    2017-09-01

    The equivalent permeability, keq of stratified fractured porous rocks and its anisotropy is important for hydrocarbon reservoir engineering, groundwater hydrology, and subsurface contaminant transport. However, it is difficult to constrain this tensor property as it is strongly influenced by infrequent large fractures. Boreholes miss them and their directional sampling bias affects the collected geostatistical data. Samples taken at any scale smaller than that of interest truncate distributions and this bias leads to an incorrect characterization and property upscaling. To better understand this sampling problem, we have investigated a collection of outcrop-data-based Discrete Fracture and Matrix (DFM) models with mechanically constrained fracture aperture distributions, trying to establish a useful Representative Elementary Volume (REV). Finite-element analysis and flow-based upscaling have been used to determine keq eigenvalues and anisotropy. While our results indicate a convergence toward a scale-invariant keq REV with increasing sample size, keq magnitude can have multi-modal distributions. REV size relates to the length of dilated fracture segments as opposed to overall fracture length. Tensor orientation and degree of anisotropy also converge with sample size. However, the REV for keq anisotropy is larger than that for keq magnitude. Across scales, tensor orientation varies spatially, reflecting inhomogeneity of the fracture patterns. Inhomogeneity is particularly pronounced where the ambient stress selectively activates late- as opposed to early (through-going) fractures. While we cannot detect any increase of keq with sample size as postulated in some earlier studies, our results highlight a strong keq anisotropy that influences scale dependence.

  13. Cavity length dependence of mode beating in passively Q-switched Nd-solid state lasers

    Science.gov (United States)

    Zameroski, Nathan D.; Wanke, Michael; Bossert, David

    2013-03-01

    The temporal intensity profile of pulse(s) from passively Q-switched and passively Q-switched mode locked (QSML) solid-state lasers is known to be dependent on cavity length. In this work, the pulse width, modulation depth, and beat frequencies of a Nd:Cr:GSGG laser using a Cr+4:YAG passive Q-switch are investigated as function cavity length. Measured temporal widths are linearly correlated with cavity length but generally 3-5 ns larger than theoretical predictions. Some cavity lengths exhibit pulse profiles with no modulation while other lengths exhibit complete amplitude modulation. The observed beat frequencies at certain cavity lengths cannot be accounted for with passively QSML models in which the pulse train repetition rate is τRT-1, τRT= round-trip time. They can be explained, however, by including coupled cavity mode-locking effects. A theoretical model developed for a two section coupled cavity semiconductor laser is adapted to a solid-state laser to interpret measured beat frequencies. We also numerically evaluate the temporal criterion required to achieve temporally smooth Q-switched pulses, versus cavity length and pump rate. We show that in flash lamp pumped systems, the difference in buildup time between longitudinal modes is largely dependent on the pump rate. In applications where short pulse delay is important, the pumping rate may limit the ability to achieve temporally smooth pulses in passively Q-switched lasers. Simulations support trends in experimental data. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. Turbulent flows over superhydrophobic surfaces with shear-dependent slip length

    Science.gov (United States)

    Khosh Aghdam, Sohrab; Seddighi, Mehdi; Ricco, Pierre

    2015-11-01

    Motivated by recent experimental evidence, shear-dependent slip length superhydrophobic surfaces are studied. Lyapunov stability analysis is applied in a 3D turbulent channel flow and extended to the shear-dependent slip-length case. The feedback law extracted is recognized for the first time to coincide with the constant-slip-length model widely used in simulations of hydrophobic surfaces. The condition for the slip parameters is found to be consistent with the experimental data and with values from DNS. The theoretical approach by Fukagata (PoF 18.5: 051703) is employed to model the drag-reduction effect engendered by the shear-dependent slip-length surfaces. The estimated drag-reduction values are in very good agreement with our DNS data. For slip parameters and flow conditions which are potentially realizable in the lab, the maximum computed drag reduction reaches 50%. The power spent by the turbulent flow on the walls is computed, thereby recognizing the hydrophobic surfaces as a passive-absorbing drag-reduction method, as opposed to geometrically-modifying techniques that do not consume energy, e.g. riblets, hence named passive-neutral. The flow is investigated by visualizations, statistical analysis of vorticity and strain rates, and quadrants of the Reynolds stresses. Part of this work was funded by Airbus Group. Simulations were performed on the ARCHER Supercomputer (UKTC Grant).

  15. Analytic determination of dynamical and mosaic length scales in a Kac glass model

    Energy Technology Data Exchange (ETDEWEB)

    Franz, S [Abdus Salam ICTP, Strada Costiera 11, PO Box 586, I-34100 Trieste (Italy); Montanari, A [Isaac Newton Institute for Mathematical Sciences 20 Clarkson Road, Cambridge, CB3 0EH (United Kingdom)

    2007-03-16

    We consider a disordered spin model with multi-spin interactions undergoing a glass transition. We introduce dynamic and static length scales and compute them in the Kac limit (long-but-finite range interactions). They diverge at the dynamic and static phase transition with exponents -1/4 and -1 (respectively). The two length scales are approximately equal well above the mode coupling transition. Their discrepancy increases rapidly as this transition is approached. We argue that this signals a crossover from mode coupling to activated dynamics. (fast track communication)

  16. The length-tension curve in muscle depends on lattice spacing

    Energy Technology Data Exchange (ETDEWEB)

    Williams, C. D.; Salcedo, M. K.; Irving, T. C.; Regnier, M.; Daniel, T. L.

    2013-07-10

    Classic interpretations of the striated muscle length–tension curve focus on how force varies with overlap of thin (actin) and thick (myosin) filaments. New models of sarcomere geometry and experiments with skinned synchronous insect flight muscle suggest that changes in the radial distance between the actin and myosin filaments, the filament lattice spacing, are responsible for between 20% and 50% of the change in force seen between sarcomere lengths of 1.4 and 3.4 µm. Thus, lattice spacing is a significant force regulator, increasing the slope of muscle's force–length dependence.

  17. Natural Length Scales of Ecological Systems: Applications at Community and Ecosystem Levels

    Directory of Open Access Journals (Sweden)

    Craig R. Johnson

    2009-06-01

    Full Text Available The characteristic, or natural, length scales of a spatially dynamic ecological landscape are the spatial scales at which the deterministic trends in the dynamic are most sharply in focus. Given recent development of techniques to determine the characteristic length scales (CLSs of real ecological systems, I explore the potential for using CLSs to address three important and vexing issues in applied ecology, viz. (i determining the optimum scales to monitor ecological systems, (ii interpreting change in ecological communities, and (iii ascertaining connectivity between species in complex ecologies. In summarizing the concept of characteristic length scales as system-level scaling thresholds, I emphasize that the primary CLS is, by definition, the optimum scale at which to monitor a system if the objective is to observe its deterministic dynamics at a system level. Using several different spatially explicit individual-based models, I then explore predictions of the underlying theory of CLSs in the context of interpreting change and ascertaining connectivity among species in ecological systems. Analysis of these models support predictions that systems with strongly fluctuating community structure, but an otherwise stable long-term dynamic defined by a stationary attractor, indicate an invariant length scale irrespective of community structure at the time of analysis, and irrespective of the species analyzed. In contrast, if changes in the underlying dynamic are forcibly induced, the shift in dynamics is reflected by a change in the primary length scale. Thus, consideration of the magnitude of the CLS through time enables distinguishing between circumstances where there are temporal changes in community structure but not in the long-term dynamic, from that where changes in community structure reflect some kind of fundamental shift in dynamics. In this context, CLSs emerge as a diagnostic tool to identify phase shifts to alternative stable states

  18. Electropolishing effect on roughness metrics of ground stainless steel: a length scale study

    Science.gov (United States)

    Nakar, Doron; Harel, David; Hirsch, Baruch

    2018-03-01

    Electropolishing is a widely-used electrochemical surface finishing process for metals. The electropolishing of stainless steel has vast commercial application, such as improving corrosion resistance, improving cleanness, and brightening. The surface topography characterization is performed using several techniques with different lateral resolutions and length scales, from atomic force microscopy in the nano-scale (process in the micro and meso lateral scales. Both stylus and optical profilometers are used, and multiple cut-off lengths of the standard Gaussian filter are adopted. While the commonly used roughness amplitude parameters (Ra, Rq and Rz) fail to characterize electropolished textures, the root mean square slope (RΔq) is found to better describe the electropolished surfaces and to be insensitive to scale.

  19. Quantum chaos of a particle in a square well: Competing length scales and dynamical localization

    Science.gov (United States)

    Sankaranarayanan, R.; Lakshminarayan, A.; Sheorey, V. B.

    2001-10-01

    The classical and quantum dynamics of a particle trapped in a one-dimensional infinite square well with a time-periodic pulsed field is investigated. This is a two-parameter non-KAM (Kolmogorov-Arnold-Moser) generalization of the kicked rotor, which can be seen as the standard map of particles subjected to both smooth and hard potentials. The virtue of the generalization lies in the introduction of an extra parameter R, which is the ratio of two length scales, namely, the well width and the field wavelength. If R is a noninteger the dynamics is discontinuous and non-KAM. We have explored the role of R in controlling the localization properties of the eigenstates. In particular, the connection between classical diffusion and localization is found to generalize reasonably well. In unbounded chaotic systems such as these, while the nearest neighbor spacing distribution of the eigenvalues is less sensitive to the nature of the classical dynamics, the distribution of participation ratios of the eigenstates proves to be a sensitive measure; in the chaotic regimes the latter is log-normal. We find that the tails of the well converged localized states are exponentially localized despite the discontinuous dynamics while the bulk part shows fluctuations that tend to be closer to random matrix theory predictions. Time evolving states show considerable R dependence, and tuning R to enhance classical diffusion can lead to significantly larger quantum diffusion for the same field strengths, an effect that is potentially observable in present day experiments.

  20. Linear intra-bone geometry dependencies of the radius: Radius length determination by maximum distal width

    International Nuclear Information System (INIS)

    Baumbach, S.F.; Krusche-Mandl, I.; Huf, W.; Mall, G.; Fialka, C.

    2012-01-01

    Purpose: The aim of the study was to investigate possible linear intra-bone geometry dependencies by determining the relation between the maximum radius length and maximum distal width in two independent populations and test for possible gender or age effects. A strong correlation can help develop more representative fracture models and osteosynthetic devices as well as aid gender and height estimation in anthropologic/forensic cases. Methods: First, maximum radius length and distal width of 100 consecutive patients, aged 20–70 years, were digitally measured on standard lower arm radiographs by two independent investigators. Second, the same measurements were performed ex vivo on a second cohort, 135 isolated, formalin fixed radii. Standard descriptive statistics as well as correlations were calculated and possible gender age influences tested for both populations separately. Results: The radiographic dataset resulted in a correlation of radius length and width of r = 0.753 (adj. R 2 = 0.563, p 2 = 0.592) and side no influence on the correlation. Radius length–width correlation for the isolated radii was r = 0.621 (adj. R 2 = 0.381, p 2 = 0.598). Conclusion: A relatively strong radius length–distal width correlation was found in two different populations, indicating that linear body proportions might not only apply to body height and axial length measurements of long bones but also to proportional dependency of bone shapes in general.

  1. Nano-scaled graphene platelets with a high length-to-width aspect ratio

    Science.gov (United States)

    Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z.

    2010-09-07

    This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.

  2. Anomalous length dependence of the conductance of graphene nanoribbons with zigzag edges

    KAUST Repository

    Bilić, Ante

    2013-01-01

    Charge transport through two sets of symmetric graphene nanoribbons with zigzag shaped edges in a two-terminal device has been investigated, using density functional theory combined with the non-equilibrium Green\\'s function method. The conductance has been explored as a function of nanoribbon length, bias voltage, and the strength of terminal coupling. The set of narrower nanoribbons, in the form of thiolated linear acenes, shows an anomalous length dependence of the conductance, which at first exhibits a drop and a minimum, followed by an evident rise. The length trend is shown to arise because of a gradual transformation in the transport mechanism, which changes from being governed by a continuum of out-of-plane π type and in-plane state channels to being fully controlled by a single, increasingly more resonant, occupied π state channel. For the set of nanoribbons with a wider profile, a steady increase is observed across the whole length range, owing to the absence of the former transport mechanism. The predicted trends are confirmed by the inclusion of self-interaction correction in the calculations. For both sets of nanoribbons the replacement of the strongly coupling thiol groups by weakly bonding phenathroline has been found to cause a strong attenuation with the length and a generally low conductance. © 2013 American Institute of Physics.

  3. Wind direction variations in the natural wind – A new length scale

    DEFF Research Database (Denmark)

    Johansson, Jens; Christensen, Silas Sverre

    2018-01-01

    During an observation period of e.g. 10min, the wind direction will differ from its mean direction for short periods of time, and a body of air will pass by from that direction before the direction changes once again. The present paper introduces a new length scale which we have labeled the angul...

  4. Channel length scaling and the impact of metal gate work function ...

    Indian Academy of Sciences (India)

    Channel length decreases and becomes crucial in deep-submicrometre technologies. In this work, we study the effect of short channel and the influences of quantum mechanical on nanoscale DG-MOSFETs. As CMOS technology continues to scale, metal gate electrodes need to be intro- duced to overcome the deleterious ...

  5. Efficient coupling of 527 nm laser beam power to a long scale-length plasma

    International Nuclear Information System (INIS)

    Moody, J.D.; Divol, L.; Glenzer, S.H.; MacKinnon, A.J.; Froula, D.H.; Gregori, G.; Kruer, W.L.; Meezan, N.B.; Suter, L.J.; Williams, E.A.; Bahr, R.; Seka, W.

    2006-01-01

    We experimentally demonstrate that application of laser smoothing schemes including smoothing by spectral dispersion (SSD) and polarization smoothing (PS) increases the intensity range for efficient coupling of frequency doubled (527 nm) laser light to a long scale-length plasma with n e /n cr equals 0.14 and T e equals 2 keV. (authors)

  6. Numerical scalings of the decay lengths in the scrape-off layer

    DEFF Research Database (Denmark)

    Militello, F.; Naulin, V; Nielsen, Anders Henry

    2013-01-01

    Numerical simulations of L-mode turbulence in the scrape-off layer (SOL) are used to construct power scaling laws for the characteristic decay lengths of the temperature, density and heat flux at the outer mid-plane. Most of the results obtained are in qualitative agreement with the experimental...

  7. Studying fractal geometry on submicron length scales by small-angle scattering

    International Nuclear Information System (INIS)

    Wong, P.; Lin, J.

    1988-01-01

    Recent studies have shown that internal surfaces of porous geological materials, such as rocks and lignite coals, can be described by fractals down to atomic length scales. In this paper, the basic properties of self-similar and self-affine fractals are reviewed and how fractal dimensions can be measured by small-angle scattering experiments are discussed

  8. Charge dependence of the plasma travel length in atmospheric-pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yambe, Kiyoyuki; Konda, Kohmei; Masuda, Seiya [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)

    2016-06-15

    Plasma plume is generated using a quartz tube, helium gas, and foil electrode by applying AC high voltage under the atmosphere. The plasma plume is released into the atmosphere from inside of the quartz tube and is seen as the continuous movement of the plasma bullet. The travel length of plasma bullet is defined from plasma energy and force due to electric field. The drift velocity of plasma bullet has the upper limit under atmospheric-pressure because the drift velocity is determined from the balance between electric field and resistive force due to collisions between plasma and air. The plasma plume charge depends on the drift velocity. Consequently, in the laminar flow of helium gas flow state, the travel length of the plasma plume logarithmically depends on the plasma plume charge which changes with both the electric field and the resistive force.

  9. Charge dependence of the plasma travel length in atmospheric-pressure plasma

    International Nuclear Information System (INIS)

    Yambe, Kiyoyuki; Konda, Kohmei; Masuda, Seiya

    2016-01-01

    Plasma plume is generated using a quartz tube, helium gas, and foil electrode by applying AC high voltage under the atmosphere. The plasma plume is released into the atmosphere from inside of the quartz tube and is seen as the continuous movement of the plasma bullet. The travel length of plasma bullet is defined from plasma energy and force due to electric field. The drift velocity of plasma bullet has the upper limit under atmospheric-pressure because the drift velocity is determined from the balance between electric field and resistive force due to collisions between plasma and air. The plasma plume charge depends on the drift velocity. Consequently, in the laminar flow of helium gas flow state, the travel length of the plasma plume logarithmically depends on the plasma plume charge which changes with both the electric field and the resistive force.

  10. Scale dependence of effective media properties

    International Nuclear Information System (INIS)

    Tidwell, V.C.; VonDoemming, J.D.; Martinez, K.

    1992-01-01

    For problems where media properties are measured at one scale and applied at another, scaling laws or models must be used in order to define effective properties at the scale of interest. The accuracy of such models will play a critical role in predicting flow and transport through the Yucca Mountain Test Site given the sensitivity of these calculations to the input property fields. Therefore, a research programhas been established to gain a fundamental understanding of how properties scale with the aim of developing and testing models that describe scaling behavior in a quantitative-manner. Scaling of constitutive rock properties is investigated through physical experimentation involving the collection of suites of gas permeability data measured over a range of discrete scales. Also, various physical characteristics of property heterogeneity and the means by which the heterogeneity is measured and described are systematically investigated to evaluate their influence on scaling behavior. This paper summarizes the approach that isbeing taken toward this goal and presents the results of a scoping study that was conducted to evaluate the feasibility of the proposed research

  11. Load dependency in force-length relations in isolated single cardiomyocytes.

    Science.gov (United States)

    Iribe, Gentaro; Kaneko, Toshiyuki; Yamaguchi, Yohei; Naruse, Keiji

    2014-08-01

    The previously reported pressure-volume (PV) relationship in frog hearts shows that end-systolic PV relation (ESPVR) is load dependent, whereas ESPVR in canine hearts is load independent. To study intrinsic cardiac mechanics in detail, it is desirable to study mechanics in a single isolated cardiomyocyte that is free from interstitial connective tissue. Previous single cell mechanics studies used a pair of carbon fibers (CF) attached to the upper surface of opposite cell ends to stretch cells. These studies showed that end-systolic force-length (FL) relation (ESFLR) is load independent. However, the range of applicable mechanical load using the conventional technique is limited because of weak cell-CF attachment. Therefore, the behavior of ESFLR in single cells under physiologically possible conditions of greater load is not yet well known. To cover wider loading range, we contrived a new method to hold cell-ends more firmly using two pairs of CF attached to both upper and bottom surfaces of cells. The new method allowed stretching cells to 2.2 μm or more in end-diastolic sarcomere length. ESFLR virtually behaves in a load independent manner only with end-diastolic sarcomere length less than 1.95 μm. It exhibited clear load dependency with higher preload, especially with low afterload conditions. Instantaneous cellular elastance curves showed that decreasing afterload enhanced relaxation and slowed time to peak elastance, as previously reported. A simulation study of a mathematical model with detailed description of thin filament activation suggested that velocity dependent thin filament inactivation is crucial for the observed load dependent behaviors and previously reported afterload dependent change in Ca(2+) transient shape. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Calibration of Eringen's small length scale coefficient for initially stressed vibrating nonlocal Euler beams based on microstructured beam model

    International Nuclear Information System (INIS)

    Wang, C M; Zhang, Z; Challamel, N; Duan, W H

    2013-01-01

    In this paper, we calibrate Eringen's small length scale coefficient e 0 for an initially stressed vibrating nonlocal Euler beam via a microstructured beam modelled by some repetitive cells comprising finite rigid segments and elastic rotational springs. By adopting the pseudo-differential operator and Padé's approximation, an analytical solution for the vibration frequency in terms of initial stress may be developed for the microstructured beam model. When comparing this analytical solution with the established exact vibration solution from the nonlocal beam theory, one finds that the calibrated Eringen's small length scale coefficient e 0 is given by e 0 = √(1/6)-(1/12)(σ 0 /σ-breve m ) where σ 0 is the initial stress and σ-breve m is the mth mode buckling stress of the corresponding local Euler beam. It is shown that e 0 varies with respect to the initial axial stress, from 1/√(12)∼0.289 at the buckling compressive stress to 1/√6∼0.408 when the axial stress is zero and it monotonically increases with increasing initial tensile stress. The small length scale coefficient e 0 , however, does not depend on the vibration/buckling mode considered. (paper)

  13. Characterizing the Surface Roughness Length Scales of Lactose Carrier Particles in Dry Powder Inhalers.

    Science.gov (United States)

    Tan, Bernice Mei Jin; Chan, Lai Wah; Heng, Paul Wan Sia

    2018-03-06

    Surface roughness is well recognized as a critical physical property of particulate systems, particularly in relation to adhesion, friction, and flow. An example is the surface property of carrier particles in carrier-based dry powder inhaler (DPI) formulations. The numerical characterization of roughness remains rather unsatisfactory due to the lack of spatial (or length scale) information about surface features when a common amplitude parameter such as average roughness ( R a ) is used. An analysis of the roughness of lactose carrier particles at three different length scales, designed for specificity to the study of interactive mixtures in DPI, was explored in this study. Three R a parameters were used to represent the microscale, intermediate scale, and macroscale roughness of six types of surface-modified carriers. Coating of micronized lactose fines on coarse carrier particles increased their microroughness from 389 to 639 nm while the macroroughness was not affected. Roller compaction at higher roll forces led to very effective surface roughening, particularly at longer length scales. Changes in R a parameters corroborated the visual observations of particles under the scanning electron microscope. Roughness at the intermediate scale showed the best correlation with the fine particle fraction (FPF) of DPI formulations. From the range of 250 to 650 nm, every 100 nm increase in the intermediate roughness led to ∼8% increase in the FPF. However, the effect of surface roughness was greatly diminished when fine lactose (median size, 9 μm) of comparable amounts to the micronized drug were added to the formulation. The combination of roughness parameters at various length scales provided much discriminatory surface information, which then revealed the "quality" of roughness necessary for improving DPI performance.

  14. Determining the minimal length scale of the generalized uncertainty principle from the entropy-area relationship

    International Nuclear Information System (INIS)

    Kim, Wontae; Oh, John J.

    2008-01-01

    We derive the formula of the black hole entropy with a minimal length of the Planck size by counting quantum modes of scalar fields in the vicinity of the black hole horizon, taking into account the generalized uncertainty principle (GUP). This formula is applied to some intriguing examples of black holes - the Schwarzschild black hole, the Reissner-Nordstrom black hole, and the magnetically charged dilatonic black hole. As a result, it is shown that the GUP parameter can be determined by imposing the black hole entropy-area relationship, which has a Planck length scale and a universal form within the near-horizon expansion

  15. Scale and space dependencies of Nitrogen variability

    Science.gov (United States)

    Tarquis, A. M.; Castellanos, M. T.; Cartagena, M. C.; Ribas, F.; Cabello, M. J.; Arce, A.; Bird, N. R. A.

    2012-04-01

    In this study we use the relative entropy (E(δ)) to investigate residual effects on wheat and grain, biomass and nitrogen content, of fertigation treatments applied to a previous crop. The wheat crop covered nine subplots from a previous experiment on melon response to fertigation. Each subplot had previously received a different level of applied nitrogen and plants from the previous melon crop had already taken up the applied nitrogen. Many factors affect these variables, causing it to vary at different scales creating a non uniform distribution. E(δ), and their increments between scales, were used to identify the scale at which the variable had a maximum structure and compare with the scaling behavior of the nitrogen applied. The E(δ)is particularly appropriate for this because of does not require any prior assumptions to the structure of the data and it is easy to calculate. The results showed that the applied nitrogen through fertirrigation dominated the wheat and grain biomass response as well as nitrogen content of the whole plant; surprisingly grain nitrogen content didn't show the same structure than the applied nitrogen. At the same time, there was a noticeable structure variation in the biomass and nitrogen content at the smaller scales that correspond to the melon cropping due to uptake of the applied nitrogen by the previous crop. The E(δ) and the increments in E(δ) help us to detect changes in the scaling behavior of all the variables studied, showing at which scale there is a maximum structure. These results are in agreement with previous studies.

  16. Uncertainty Quantification in Scale-Dependent Models of Flow in Porous Media: SCALE-DEPENDENT UQ

    Energy Technology Data Exchange (ETDEWEB)

    Tartakovsky, A. M. [Computational Mathematics Group, Pacific Northwest National Laboratory, Richland WA USA; Panzeri, M. [Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Milano Italy; Tartakovsky, G. D. [Hydrology Group, Pacific Northwest National Laboratory, Richland WA USA; Guadagnini, A. [Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Milano Italy

    2017-11-01

    Equations governing flow and transport in heterogeneous porous media are scale-dependent. We demonstrate that it is possible to identify a support scale $\\eta^*$, such that the typically employed approximate formulations of Moment Equations (ME) yield accurate (statistical) moments of a target environmental state variable. Under these circumstances, the ME approach can be used as an alternative to the Monte Carlo (MC) method for Uncertainty Quantification in diverse fields of Earth and environmental sciences. MEs are directly satisfied by the leading moments of the quantities of interest and are defined on the same support scale as the governing stochastic partial differential equations (PDEs). Computable approximations of the otherwise exact MEs can be obtained through perturbation expansion of moments of the state variables in orders of the standard deviation of the random model parameters. As such, their convergence is guaranteed only for the standard deviation smaller than one. We demonstrate our approach in the context of steady-state groundwater flow in a porous medium with a spatially random hydraulic conductivity.

  17. Length-scale effect due to periodic variation of geometrically necessary dislocation densities

    DEFF Research Database (Denmark)

    Oztop, M. S.; Niordson, Christian Frithiof; Kysar, J. W.

    2013-01-01

    Strain gradient plasticity theories have been successful in predicting qualitative aspects of the length scale effect, most notably the increase in yield strength and hardness as the size of the deforming volume decreases. However new experimental methodologies enabled by recent developments...... the microstructure of deformed metals in addition to the size effect. Recent GND measurements have revealed a distribution of length scales that evolves within a metal undergoing plastic deformation. Furthermore, these experiments have shown an accumulation of GND densities in cell walls as well as a variation...... of the saturation value of dislocation densities in these cell walls and dislocation structures. In this study, a strain gradient plasticity framework is extended by incorporating the physical quantities obtained from experimental observations: the quasi-periodicity and the saturation value of GND densities...

  18. The "lotus effect" explained: two reasons why two length scales of topography are important.

    Science.gov (United States)

    Gao, Lichao; McCarthy, Thomas J

    2006-03-28

    Surfaces containing 4 x 8 x 40 microm staggered rhombus posts were hydrophobized using two methods. One, using a dimethyldichlorosilane reaction in the vapor phase, introduces a smooth modified layer, and the other, a solution reaction using methyltrichlorosilane, imparts a second (nanoscopic) length scale of topography. The smooth modified surface exhibits contact angles of thetaA/thetaR = 176 degrees /156 degrees . Arguments are made that the pinning of the receding contact line by the post tops (with thetaA/thetaR = 104 degrees /103 degrees ) is responsible for the hysteresis. The second level of topography raises the contact angles of the post tops and the macroscopic sample to theta(A)/theta(R) = >176 degrees />176 degrees and eliminates hysteresis. The increase in Laplace pressure due to the increase in the advancing contact angle of the post tops is a second reason that two length scales of topography are important.

  19. Scale dependence and small x behaviour of polarized parton distributions

    CERN Document Server

    Ball, R D; Ridolfi, G; Forte, S; Ridolfi, G

    1995-01-01

    We discuss perturbative evolution of the polarized structure function g_1 in the (x,Q^2) plane, with special regard to the small-x region. We determine g_1 in terms of polarized quark and gluon distributions using coefficient functions to order alpha_s. At small x g_1 then displays substantial scale dependence, which necessarily implies a corresponding scale dependence in the large-x region. This scale dependence has significant consequences for the extraction of the first moment from the experimental data, reducing its value while increasing the error. Conversely, the scale dependence may be used to constrain the size of the polarized gluon distribution.

  20. Scheme and scale dependences of leading electroweak corrections

    International Nuclear Information System (INIS)

    Kniehl, B.A.; Sirlin, A.

    1996-01-01

    The scheme and scale dependences of leading M t -dependent contributions to Δρ, Δr, and τ, which arise because of the truncation of the perturbative series, are investigated by comparing expressions in the on-shell and MS schemes of renormalization, and studying their scale variations. Starting from the conventional on-shell formulae, we find rather large scheme and scale dependences. We then propose a simple, physically motivated modification of the conventional expressions and show that it leads to a sharp reduction in the scheme and scale dependences. Implications for electroweak physics are discussed. (orig.)

  1. Validity and factor structure of the bodybuilding dependence scale

    OpenAIRE

    Smith, D; Hale, B

    2004-01-01

    Objectives: To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders.

  2. Towards a taxonomy of spatial scale-dependence

    DEFF Research Database (Denmark)

    Sandel, Brody Steven

    2015-01-01

    Spatial scale-dependence is a ubiquitous feature of ecological systems. This presents a challenge for ecologists who seek to discern general principles. A solution is to search for generalities in patterns of scale-dependence – that is, what kinds of things are scale-dependent, in what ways...... major types in hopes of moving towards a more formal and unambiguous vocabulary. I argue that three major distinctions are necessary and sufficient for this goal: that between grain size and extent (the scale component), between data and models (the subject), and between true and perceived scale...

  3. Observation of two length scales in the magnetic critical fluctuations of holmium

    International Nuclear Information System (INIS)

    Thurston, T.R.; Helgesen, G.; Gibbs, D.; Hill, J.P.; Gaulin, B.D.; Shirane, G.

    1993-01-01

    The short-ranged correlations associated with magneitc ordering in the rare earth antiferromagnet holmium have been characterized in high-resolution x-ray and neutron scattering studies. We find that within about 2 K of T c , the magnetic fluctuations exhibit two length scales, instead of one as expected in an ideal system. This result is reminiscent of behavior observed at the cubic-to-tegragonal structural phase transitions of the perovskites

  4. Gain length dependence on phase shake in the VUV-FEL at the TESLA Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Pflueger, J. [DESY/HASYLAB, Hamburg (Germany); Schneidmiller, E.A. [Automatic Systems Corporation, Samara (Russian Federation); Pierini, P. [INFN, Milano (Italy)

    1995-12-31

    The TTF VUV FEL, which is in its design stage at DESY, consists of a 30 m long SASE FEL which will radiate around 6 nm, driven by a superconducting linac with final energy of 1 GeV. One of the important issues in its design is the undulator performance, which is studied in this paper. The present setup, including FODO lattice, is discussed in this paper. Results of simulations, including the realistic wiggler field errors and beam stearing, are presented. Dependence of the performance, in particular the gain and saturation length as well as the saturation peak power, on the wiggler field errors is discussed.

  5. Length scale effects and multiscale modeling of thermally induced phase transformation kinetics in NiTi SMA

    Science.gov (United States)

    Frantziskonis, George N.; Gur, Sourav

    2017-06-01

    Thermally induced phase transformation in NiTi shape memory alloys (SMAs) shows strong size and shape, collectively termed length scale effects, at the nano to micrometer scales, and that has important implications for the design and use of devices and structures at such scales. This paper, based on a recently developed multiscale model that utilizes molecular dynamics (MDs) simulations at small scales and MD-verified phase field (PhF) simulations at larger scales, reports results on specific length scale effects, i.e. length scale effects in martensite phase fraction (MPF) evolution, transformation temperatures (martensite and austenite start and finish) and in the thermally cyclic transformation between austenitic and martensitic phase. The multiscale study identifies saturation points for length scale effects and studies, for the first time, the length scale effect on the kinetics (i.e. developed internal strains) in the B19‧ phase during phase transformation. The major part of the work addresses small scale single crystals in specific orientations. However, the multiscale method is used in a unique and novel way to indirectly study length scale and grain size effects on evolution kinetics in polycrystalline NiTi, and to compare the simulation results to experiments. The interplay of the grain size and the length scale effect on the thermally induced MPF evolution is also shown in this present study. Finally, the multiscale coupling results are employed to improve phenomenological material models for NiTi SMA.

  6. Image processing for quantifying fracture orientation and length scale transitions during brittle deformation

    Science.gov (United States)

    Rizzo, R. E.; Healy, D.; Farrell, N. J.

    2017-12-01

    We have implemented a novel image processing tool, namely two-dimensional (2D) Morlet wavelet analysis, capable of detecting changes occurring in fracture patterns at different scales of observation, and able of recognising the dominant fracture orientations and the spatial configurations for progressively larger (or smaller) scale of analysis. Because of its inherited anisotropy, the Morlet wavelet is proved to be an excellent choice for detecting directional linear features, i.e. regions where the amplitude of the signal is regular along one direction and has sharp variation along the perpendicular direction. Performances of the Morlet wavelet are tested against the 'classic' Mexican hat wavelet, deploying a complex synthetic fracture network. When applied to a natural fracture network, formed triaxially (σ1>σ2=σ3) deforming a core sample of the Hopeman sandstone, the combination of 2D Morlet wavelet and wavelet coefficient maps allows for the detection of characteristic scale orientation and length transitions, associated with the shifts from distributed damage to the growth of localised macroscopic shear fracture. A complementary outcome arises from the wavelet coefficient maps produced by increasing the wavelet scale parameter. These maps can be used to chart the variations in the spatial distribution of the analysed entities, meaning that it is possible to retrieve information on the density of fracture patterns at specific length scales during deformation.

  7. Chirality transfer across length-scales in nematic liquid crystals: fundamentals and applications.

    Science.gov (United States)

    Pieraccini, Silvia; Masiero, Stefano; Ferrarini, Alberta; Piero Spada, Gian

    2011-01-01

    When a chiral dopant is dissolved in an achiral liquid crystal medium, the whole sample organizes into a helical structure with a characteristic length-scale of the order of microns. The relation between chirality at these quite different length-scales can be rationalized by a relatively simple model, which retains the relevant factors coming into play: the molecular shape of the chiral dopant, which controls the chirality of short range intermolecular interactions, and the elastic properties of the nematic environment, which control the restoring torques opposing distortion of the director. In this tutorial review the relation between molecular and phase chirality will be reviewed and several applications of the chiral doping of nematic LCs will be discussed. These range from the exploitation of the amplified molecular chirality for stereochemical purposes (e.g., the determination of the absolute configuration or the enantiomeric excess), to newer applications in physico-chemical fields. The latter take advantage of the periodicity of the chiral field, with length-scales ranging from hundreds to thousands of nanometres, which characterise the cholesteric phase.

  8. Differential scaling patterns of vertebrae and the evolution of neck length in mammals.

    Science.gov (United States)

    Arnold, Patrick; Amson, Eli; Fischer, Martin S

    2017-06-01

    Almost all mammals have seven vertebrae in their cervical spines. This consistency represents one of the most prominent examples of morphological stasis in vertebrae evolution. Hence, the requirements associated with evolutionary modifications of neck length have to be met with a fixed number of vertebrae. It has not been clear whether body size influences the overall length of the cervical spine and its inner organization (i.e., if the mammalian neck is subject to allometry). Here, we provide the first large-scale analysis of the scaling patterns of the cervical spine and its constituting cervical vertebrae. Our findings reveal that the opposite allometric scaling of C1 and C2-C7 accommodate the increase of neck bending moment with body size. The internal organization of the neck skeleton exhibits surprisingly uniformity in the vast majority of mammals. Deviations from this general pattern only occur under extreme loading regimes associated with particular functional and allometric demands. Our results indicate that the main source of variation in the mammalian neck stems from the disparity of overall cervical spine length. The mammalian neck reveals how evolutionary disparity manifests itself in a structure that is otherwise highly restricted by meristic constraints. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  9. Gate length scaling trends of drive current enhancement in CMOSFETs with dual stress overlayers and embedded-SiGe

    International Nuclear Information System (INIS)

    Flachowsky, S.; Wei, A.; Herrmann, T.; Illgen, R.; Horstmann, M.; Richter, R.; Salz, H.; Klix, W.; Stenzel, R.

    2008-01-01

    Strain engineering in MOSFETs using tensile nitride overlayer (TOL) films, compressive nitride overlayer (COL) films, and embedded-SiGe (eSiGe) is studied by extensive device experiments and numerical simulations. The scaling behavior was analyzed by gate length reduction down to 40 nm and it was found that drive current strongly depends on the device dimensions. The reduction of drain-current enhancement for short-channel devices can be attributed to two competing factors: shorter gate length devices have increased longitudinal and vertical stress components which should result in improved drain-currents. However, there is a larger degradation from external resistance as the gate length decreases, due to a larger voltage dropped across the external resistance. Adding an eSiGe stressor reduces the external resistance in the p-MOSFET, to the extent that the drive current improvement from COL continues to increase even down the shortest gate length studied. This is due to the reduced resistivity of SiGe itself and the SiGe valence band offset relative to Si, leading to a smaller silicide-active contact resistance. It demonstrates the advantage of combining eSiGe and COL, not only for increased stress, but also for parasitic resistance reduction to enable better COL drive current benefit

  10. Magnetic field dependence of microwave radiation in intermediate-length Josephson junctions

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Parmentier, R. D.; Christiansen, Peter Leth

    1984-01-01

    Experimental measurements of current-voltage structure and emitted X-band radiation in applied magnetic field from overlap-geometry Josephson tunnel junctions of normalized length about 2 are compared with numerical simulations obtained with the use of a perturbed sine-Gordon model. The simulations...... Fiske step in magnetic field and the field dependence of the radiation frequency within the various lobes, including details such as hysteresis between lobes. The simulations predict an alternation of the dominant frequency component with increasing field that accounts well for the experimental...... furnish the current and field dependence of the oscillation configuration, from which can be calculated average voltages, frequencies, and power spectra. Simulation and experimental results are in good agreement with regard to the lobe structure of the height of the first zero-field step and/or second...

  11. Protein resistance efficacy of PEO-silane amphiphiles: Dependence on PEO-segment length and concentration.

    Science.gov (United States)

    Rufin, Marc A; Barry, Mikayla E; Adair, Paige A; Hawkins, Melissa L; Raymond, Jeffery E; Grunlan, Melissa A

    2016-09-01

    In contrast to modification with conventional PEO-silanes (i.e. no siloxane tether), silicones with dramatically enhanced protein resistance have been previously achieved via bulk-modification with poly(ethylene oxide) (PEO)-silane amphiphiles α-(EtO)3Si(CH2)2-oligodimethylsiloxane13-block-PEOn-OCH3 when n=8 and 16 but not when n=3. In this work, their efficacy was evaluated in terms of optimal PEO-segment length and minimum concentration required in silicone. For each PEO-silane amphiphile (n=3, 8, and 16), five concentrations (5, 10, 25, 50, and 100μmol per 1g silicone) were evaluated. Efficacy was quantified in terms of the modified silicones' abilities to undergo rapid, water-driven surface restructuring to form hydrophilic surfaces as well as resistance to fibrinogen adsorption. Only n=8 and 16 were effective, with a lower minimum concentration in silicone required for n=8 (10μmol per 1g silicone) versus n=16 (25μmol per 1g silicone). Silicone is commonly used for implantable medical devices, but its hydrophobic surface promotes protein adsorption which leads to thrombosis and infection. Typical methods to incorporate poly(ethylene oxide) (PEO) into silicones have not been effective due to the poor migration of PEO to the surface-biological interface. In this work, PEO-silane amphiphiles - comprised of a siloxane tether (m=13) and variable PEO segment lengths (n=3, 8, 16) - were blended into silicone to improve its protein resistance. The efficacy of the amphiphiles was determined to be dependent on PEO length. With the intermediate PEO length (n=8), water-driven surface restructuring and resulting protein resistance was achieved with a concentration of only 1.7wt%. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. Lower Length Scale Model Development for Embrittlement of Reactor Presure Vessel Steel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Schwen, Daniel [Idaho National Lab. (INL), Idaho Falls, ID (United States); Chakraborty, Pritam [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bai, Xianming [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    This report summarizes the lower-length-scale effort during FY 2016 in developing mesoscale capabilities for microstructure evolution, plasticity and fracture in reactor pressure vessel steels. During operation, reactor pressure vessels are subject to hardening and embrittlement caused by irradiation induced defect accumulation and irradiation enhanced solute precipitation. Both defect production and solute precipitation start from the atomic scale, and manifest their eventual effects as degradation in engineering scale properties. To predict the property degradation, multiscale modeling and simulation are needed to deal with the microstructure evolution, and to link the microstructure feature to material properties. In this report, the development of mesoscale capabilities for defect accumulation and solute precipitation are summarized. A crystal plasticity model to capture defect-dislocation interaction and a damage model for cleavage micro-crack propagation is also provided.

  13. Self-Consistent Field Theories for the Role of Large Length-Scale Architecture in Polymers

    Science.gov (United States)

    Wu, David

    At large length-scales, the architecture of polymers can be described by a coarse-grained specification of the distribution of branch points and monomer types within a molecule. This includes molecular topology (e.g., cyclic or branched) as well as distances between branch points or chain ends. Design of large length-scale molecular architecture is appealing because it offers a universal strategy, independent of monomer chemistry, to tune properties. Non-linear analogs of linear chains differ in molecular-scale properties, such as mobility, entanglements, and surface segregation in blends that are well-known to impact rheological, dynamical, thermodynamic and surface properties including adhesion and wetting. We have used Self-Consistent Field (SCF) theories to describe a number of phenomena associated with large length-scale polymer architecture. We have predicted the surface composition profiles of non-linear chains in blends with linear chains. These predictions are in good agreement with experimental results, including from neutron scattering, on a range of well-controlled branched (star, pom-pom and end-branched) and cyclic polymer architectures. Moreover, the theory allows explanation of the segregation and conformations of branched polymers in terms of effective surface potentials acting on the end and branch groups. However, for cyclic chains, which have no end or junction points, a qualitatively different topological mechanism based on conformational entropy drives cyclic chains to a surface, consistent with recent neutron reflectivity experiments. We have also used SCF theory to calculate intramolecular and intermolecular correlations for polymer chains in the bulk, dilute solution, and trapped at a liquid-liquid interface. Predictions of chain swelling in dilute star polymer solutions compare favorably with existing PRISM theory and swelling at an interface helps explain recent measurements of chain mobility at an oil-water interface. In collaboration

  14. Second-moment closures and length scales for weakly stratified turbulent shear flows

    Science.gov (United States)

    Baumert, Helmut; Peters, Hartmut

    2000-03-01

    For the special hydrodynamic situation of unbounded homogeneous shear layers, turbulence closure models of Mellor-Yamada type (MY) and k-ɛ type are put into a single canonical form. For this situation we show that conventional versions of MY and various k-ɛ versions lack a proper steady state, and are unable to simulate the most basic properties of stratified shear flows exemplified in, for example, the Rohr et al. [1988] experiments: exponential growth at sufficiently low gradient Richardson number (Rg), exponential decay at sufficiently large Rg, and a steady state in between. Proper choice of one special model parameter readily solves the problems. In the fairly general case of structural equilibrium (state of exponential evolution) in weakly to moderately stratified turbulence (Rg ≲ 0.25), the ratio between the Thorpe scale (or Ellison scale) and the Ozmidov scale varies like the gradient Richardson number (Rg) to the power 3/4, and the ratio of the Thorpe scale to the buoyancy scale varies like Rg1/2. Length scales predicted by our current model are consistent with laboratory measurements of Rohr et al. [1988], with large-eddy numerical simulations of Schumann and Gerz [1995], and with microstructure measurements from the 1987 Tropic Heat Experiment in the equatorial Pacific by Peters et al. [1995].

  15. Nature of the spin-glass phase at experimental length scales

    International Nuclear Information System (INIS)

    Alvarez Baños, R; Cruz, A; Fernandez, L A; Gil-Narvion, J M; Gordillo-Guerrero, A; Maiorano, A; Martin-Mayor, V; Monforte-Garcia, J; Perez-Gaviro, S; Ruiz-Lorenzo, J J; Seoane, B; Tarancon, A; Guidetti, M; Mantovani, F; Schifano, S F; Tripiccione, R; Marinari, E; Parisi, G; Muñoz Sudupe, A; Navarro, D

    2010-01-01

    We present a massive equilibrium simulation of the three-dimensional Ising spin glass at low temperatures. The Janus special-purpose computer has allowed us to equilibrate, using parallel tempering, L = 32 lattices down to T ≈ 0.64T c . We demonstrate the relevance of equilibrium finite size simulations to understanding experimental non-equilibrium spin glasses in the thermodynamical limit by establishing a time-length dictionary. We conclude that non-equilibrium experiments performed on a timescale of 1 h can be matched with equilibrium results on L ≈ 110 lattices. A detailed investigation of the probability distribution functions of the spin and link overlap, as well as of their correlation functions, shows that Replica Symmetry Breaking is the appropriate theoretical framework for the physically relevant length scales. Besides, we improve over existing methodologies in ensuring equilibration in parallel tempering simulations

  16. Characteristic length scale of input data in distributed models: implications for modeling grid size

    Science.gov (United States)

    Artan, G. A.; Neale, C. M. U.; Tarboton, D. G.

    2000-01-01

    The appropriate spatial scale for a distributed energy balance model was investigated by: (a) determining the scale of variability associated with the remotely sensed and GIS-generated model input data; and (b) examining the effects of input data spatial aggregation on model response. The semi-variogram and the characteristic length calculated from the spatial autocorrelation were used to determine the scale of variability of the remotely sensed and GIS-generated model input data. The data were collected from two hillsides at Upper Sheep Creek, a sub-basin of the Reynolds Creek Experimental Watershed, in southwest Idaho. The data were analyzed in terms of the semivariance and the integral of the autocorrelation. The minimum characteristic length associated with the variability of the data used in the analysis was 15 m. Simulated and observed radiometric surface temperature fields at different spatial resolutions were compared. The correlation between agreement simulated and observed fields sharply declined after a 10×10 m2 modeling grid size. A modeling grid size of about 10×10 m2 was deemed to be the best compromise to achieve: (a) reduction of computation time and the size of the support data; and (b) a reproduction of the observed radiometric surface temperature.

  17. Characteristic length scale of input data in distributed models: implications for modeling grain size

    Science.gov (United States)

    Artan, Guleid A.; Neale, C. M. U.; Tarboton, D. G.

    2000-01-01

    The appropriate spatial scale for a distributed energy balance model was investigated by: (a) determining the scale of variability associated with the remotely sensed and GIS-generated model input data; and (b) examining the effects of input data spatial aggregation on model response. The semi-variogram and the characteristic length calculated from the spatial autocorrelation were used to determine the scale of variability of the remotely sensed and GIS-generated model input data. The data were collected from two hillsides at Upper Sheep Creek, a sub-basin of the Reynolds Creek Experimental Watershed, in southwest Idaho. The data were analyzed in terms of the semivariance and the integral of the autocorrelation. The minimum characteristic length associated with the variability of the data used in the analysis was 15 m. Simulated and observed radiometric surface temperature fields at different spatial resolutions were compared. The correlation between agreement simulated and observed fields sharply declined after a 10×10 m2 modeling grid size. A modeling grid size of about 10×10 m2 was deemed to be the best compromise to achieve: (a) reduction of computation time and the size of the support data; and (b) a reproduction of the observed radiometric surface temperature.

  18. [Regulation of the length of the snail tentacle by the concentration-dependent contraction].

    Science.gov (United States)

    Nikitin, E S; Zakharov, I S; Balaban, P M

    2004-01-01

    The tentacle of terrestrial snail with olfactory organs on the tips display complex behavior when snail investigates the new environment. We reconstructed the trajectory of the tentacle in three dimensions from two simultaneous video recordings in freely moving snail without odor and after odor application. We found that without oder the snail displayed continuous environment scanning with elongated tentacles. Odor application elicited startle-like short-term flexions of the tentacle which were independent from odor concentration and concentration-dependent gradual tentacle contraction. Identified central motoneuron MtC3 is known to produce the most part of the central tentacle retraction to the noxious stimuli. In nose-brain preparation the MtC3 responded to odors in concentration-dependent manner similar by dynamics and duration to the concentration-dependent gradual tentacle contraction in intact snail. It suggests that the MtC3 provides the central control of the extent of the scanning area by limiting the tentacle length. The MtC3-related gradual contraction of the tentacle can be aimed to tune the olfactory behavior of the terrestrial snail to the particular odor environment.

  19. Titin isoform variance and length dependence of activation in skinned bovine cardiac muscle.

    Science.gov (United States)

    Fukuda, Norio; Wu, Yiming; Farman, Gerrie; Irving, Thomas C; Granzier, Henk

    2003-11-15

    We have explored the role of the giant elastic protein titin in the Frank-Starling mechanism of the heart by measuring the sarcomere length (SL) dependence of activation in skinned cardiac muscles with different titin-based passive stiffness characteristics. We studied muscle from the bovine left ventricle (BLV), which expresses a high level of a stiff titin isoform, and muscle from the bovine left atrium (BLA), which expresses more compliant titin isoforms. Passive tension was also varied in each muscle type by manipulating the pre-history of stretch prior to activation. We found that the SL-dependent increases in Ca2+ sensitivity and maximal Ca2+-activated tension were markedly more pronounced when titin-based passive tension was high. Small-angle X-ray diffraction experiments revealed that the SL dependence of reduction of interfilament lattice spacing is greater in BLV than in BLA and that the lattice spacing is coupled with titin-based passive tension. These results support the notion that titin-based passive tension promotes actomyosin interaction by reducing the lattice spacing. This work indicates that titin may be a factor involved in the Frank-Starling mechanism of the heart by promoting actomyosin interaction in response to stretch.

  20. Studies on jet path length dependence in Pb+Pb Collisions with the ATLAS detector

    CERN Document Server

    Santos, Helena; The ATLAS collaboration

    2015-01-01

    The phenomenon of events containing highly asymmetric dijet pairs is one of the most striking results in heavy ion physics. It has provided the first direct observation of in-medium jet energy loss at the LHC. New results showing the variation of the dijet asymmetry with the angle between the leading jet and the second order event-plane are presented. This observable effectively probes the path-length dependence of the *dijet* asymmetry at fixed centrality. The variation of the dijet asymmetry with the soft particle $v_2$, at fixed centrality is also measured. These measurements can provide a better understanding of the correlation of the parton energy-loss with the underlying geometry. Correlated production of nearby jets is also shown. Two neighbouring jets originating from the same hard scattering should have more similar path lengths in the medium compared to the two jets in the dijet event topology, therefore measuring neighbouring jets may probe differences in quenching that do not result from different...

  1. Penetration length-dependent hot electrons in the field emission from ZnO nanowires

    Science.gov (United States)

    Chen, Yicong; Song, Xiaomeng; Li, Zhibing; She, Juncong; Deng, Shaozhi; Xu, Ningsheng; Chen, Jun

    2018-01-01

    In the framework of field emission, whether or not hot electrons can form in the semiconductor emitters under a surface penetration field is of great concern, which will provide not only a comprehensive physical picture of field emission from semiconductor but also guidance on how to improve device performance. However, apart from some theoretical work, its experimental evidence has not been reported yet. In this article, the field penetration length-dependent hot electrons were observed in the field emission of ZnO nanowires through the in-situ study of its electrical and field emission characteristic before and after NH3 plasma treatment in an ultrahigh vacuum system. After the treatment, most of the nanowires have an increased carrier density but reduced field emission current. The raised carrier density was caused by the increased content of oxygen vacancies, while the degraded field emission current was attributed to the lower kinetic energy of hot electrons caused by the shorter penetration length. All of these results suggest that the field emission properties of ZnO nanowires can be optimized by modifying their carrier density to balance both the kinetic energy of field induced hot electrons and the limitation of saturated current under a given field.

  2. Synchrotron X-Ray Scattering as a Tool for Characterising Catalysts on Multiple Length Scales

    International Nuclear Information System (INIS)

    Hudspeth, Jessica M.; Kvashnina, Kristina O.; Kimber, Simon A.J.; Mitchell, Edward P.

    2015-01-01

    Optimising the properties of catalysts for industrial processes requires a detailed knowledge of their structure and properties on multiple length scales. Synchrotron light sources are ideal tools for characterising catalysts for industrial R and D, providing data with high temporal and spatial resolution, under realistic operating conditions, in a non-destructive way. Here, we describe the different synchrotron techniques that can be employed to gain a wealth of complementary information, and highlight recent developments that have allowed remarkable insight to be gained into working catalytic systems. These techniques have the potential to guide future industrial catalyst design. (authors)

  3. Explanation of the values of Hack's drainage basin, river length scaling exponent

    Science.gov (United States)

    Hunt, A. G.

    2015-08-01

    Percolation theory can be used to find water flow paths of least resistance. The application of percolation theory to drainage networks allows identification of the range of exponent values that describe the tortuosity of rivers in real river networks, which is then used to generate the observed scaling between drainage basin area and channel length, a relationship known as Hack's law. Such a theoretical basis for Hack's law allows interpretation of the range of exponent values based on an assessment of the heterogeneity of the substrate.

  4. Brief communication: Possible explanation of the values of Hack's drainage basin, river length scaling exponent

    Science.gov (United States)

    Hunt, Allen G.

    2016-04-01

    Percolation theory can be used to find water flow paths of least resistance. Application of percolation theory to drainage networks allows identification of the range of exponent values that describe the tortuosity of rivers in real river networks, which is then used to generate the observed scaling between drainage basin area and channel length, a relationship known as Hack's law. Such a theoretical basis for Hack's law may allow interpretation of the range of exponent values based on an assessment of the heterogeneity of the substrate.

  5. A multiple length scale description of the mechanism of elastomer stretching

    DEFF Research Database (Denmark)

    Neuefeind, J.; Skov, Anne Ladegaard; Daniels, J. E.

    2016-01-01

    Conventionally, the stretching of rubber is modeled exclusively by rotations of segments of the embedded polymer chains; i.e. changes in entropy. However models have not been tested on all relevant length scales due to a lack of appropriate probes. Here we present a universal X-ray based method...... within the individual monomers, but among the contributions is also an elastic strain, acting between chains, which is 3-4 orders of magnitude smaller than the macroscopic strain, and of the opposite sign, i.e. extension of polymer chains in the direction perpendicular to the stretch. This may be due...

  6. Variable length and context-dependent HMM letter form models for Arabic handwritten word recognition

    Science.gov (United States)

    Bianne-Bernard, Anne-Laure; Menasri, Fares; Likforman-Sulem, Laurence; Mokbel, Chafic; Kermorvant, Christopher

    2012-01-01

    We present in this paper an HMM-based recognizer for the recognition of unconstrained Arabic handwritten words. The recognizer is a context-dependent HMM which considers variable topology and contextual information for a better modeling of writing units. We propose an algorithm to adapt the topology of each HMM to the character to be modeled. For modeling the contextual units, a state-tying process based on decision tree clustering is introduced which significantly reduces the number of parameters. Decision trees are built according to a set of expert-based questions on how characters are written. Questions are divided into global questions yielding larger clusters and precise questions yielding smaller ones. We apply this modeling to the recognition of Arabic handwritten words. Experiments conducted on the OpenHaRT2010 database show that variable length topology and contextual information significantly improves the recognition rate.

  7. Effects of fracture distribution and length scale on the equivalent continuum elastic compliance of fractured rock masses

    Directory of Open Access Journals (Sweden)

    Marte Gutierrez

    2015-12-01

    Full Text Available Fracture systems have strong influence on the overall mechanical behavior of fractured rock masses due to their relatively lower stiffness and shear strength than those of the rock matrix. Understanding the effects of fracture geometrical distribution, such as length, spacing, persistence and orientation, is important for quantifying the mechanical behavior of fractured rock masses. The relation between fracture geometry and the mechanical characteristics of the fractured rock mass is complicated due to the fact that the fracture geometry and mechanical behaviors of fractured rock mass are strongly dependent on the length scale. In this paper, a comprehensive study was conducted to determine the effects of fracture distribution on the equivalent continuum elastic compliance of fractured rock masses over a wide range of fracture lengths. To account for the stochastic nature of fracture distributions, three different simulation techniques involving Oda's elastic compliance tensor, Monte Carlo simulation (MCS, and suitable probability density functions (PDFs were employed to represent the elastic compliance of fractured rock masses. To yield geologically realistic results, parameters for defining fracture distributions were obtained from different geological fields. The influence of the key fracture parameters and their relations to the overall elastic behavior of the fractured rock mass were studied and discussed. A detailed study was also carried out to investigate the validity of the use of a representative element volume (REV in the equivalent continuum representation of fractured rock masses. A criterion was also proposed to determine the appropriate REV given the fracture distribution of the rock mass.

  8. Scale-dependent background-error covariance localisation

    Directory of Open Access Journals (Sweden)

    Mark Buehner

    2015-12-01

    Full Text Available A new approach is presented and evaluated for efficiently applying scale-dependent spatial localisation to ensemble background-error covariances within an ensemble-variational data assimilation system. The approach is primarily motivated by the requirements of future data assimilation systems for global numerical weather prediction that will be capable of resolving the convective scale. Such systems must estimate the global and synoptic scales at least as well as current global systems while also effectively making use of information from frequent and spatially dense observation networks to constrain convective-scale features. Scale-dependent covariance localisation allows a wider range of scales to be efficiently estimated while simultaneously assimilating all available observations. In the context of an idealised numerical experiment, it is shown that using scale-dependent localisation produces an improved ensemble-based estimate of spatially varying covariances as compared with standard spatial localisation. When applied to an ensemble of Arctic sea-ice concentration, it is demonstrated that strong spatial gradients in the relative contribution of different spatial scales in the ensemble covariances result in strong spatial variations in the overall amount of spatial localisation. This feature is qualitatively similar to what might be expected when applying an adaptive localisation approach that estimates a spatially varying localisation function from the ensemble itself. When compared with standard spatial localisation, scale-dependent localisation also results in a lower analysis error for sea-ice concentration over all spatial scales.

  9. Lead Selenide Nanostructures Self-Assembled across Multiple Length Scales and Dimensions

    Directory of Open Access Journals (Sweden)

    Evan K. Wujcik

    2016-01-01

    Full Text Available A self-assembly approach to lead selenide (PbSe structures that have organized across multiple length scales and multiple dimensions has been achieved. These structures consist of angstrom-scale 0D PbSe crystals, synthesized via a hot solution process, which have stacked into 1D nanorods via aligned dipoles. These 1D nanorods have arranged into nanoscale 2D sheets via directional short-ranged attraction. The nanoscale 2D sheets then further aligned into larger 2D microscale planes. In this study, the authors have characterized the PbSe structures via normal and cryo-TEM and EDX showing that this multiscale multidimensional self-assembled alignment is not due to drying effects. These PbSe structures hold promise for applications in advanced materials—particularly electronic technologies, where alignment can aid in device performance.

  10. Strain rate, temperature and representative length scale influence on plasticity and yield stress in copper

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Virginie [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory

    2011-01-18

    Shock compression of materials constitutes a complex process involving high strain rates, elevated temperatures and compression of the lattice. Materials properties are greatly affected by temperature, the representative length scale and the strain rate of the deformation. Experimentally, it is difficult to study the dynamic microscopic mechanisms that affect materials properties following high intensity shock loading, but they can be investigated using molecular dynamics (MD) simulations. Moreover, MD allows a better control over some parameters. We are using MD simulations to study the effect of the strain rate, representative length scale and temperature on the properties of metals during compression. A half-million-atom Cu sample is subjected to strain rates ranging from 10{sup 7} s{sup -1} to 10{sup 12} s{sup -1} at different temperatures ranging from 50K to 1500K. Single crystals as well as polycrystals are investigated. Plasticity mechanisms as well as the evolution of the micro- and macro-yield stress are observed. Our results show that the yield stress increases with increasing strain rate and decreasing temperature. We also show that the strain rate at which the transition between constant and increasing yield stress as a function of the temperature occurs increases with increasing temperature. Calculations at different grain sizes will give an insight into the grain size effect on the plasticity mechanisms and the yield stress.

  11. A stochastic immersed boundary method for fluid-structure dynamics at microscopic length scales

    International Nuclear Information System (INIS)

    Atzberger, Paul J.; Kramer, Peter R.; Peskin, Charles S.

    2007-01-01

    In modeling many biological systems, it is important to take into account flexible structures which interact with a fluid. At the length scale of cells and cell organelles, thermal fluctuations of the aqueous environment become significant. In this work, it is shown how the immersed boundary method of [C.S. Peskin, The immersed boundary method, Acta Num. 11 (2002) 1-39.] for modeling flexible structures immersed in a fluid can be extended to include thermal fluctuations. A stochastic numerical method is proposed which deals with stiffness in the system of equations by handling systematically the statistical contributions of the fastest dynamics of the fluid and immersed structures over long time steps. An important feature of the numerical method is that time steps can be taken in which the degrees of freedom of the fluid are completely underresolved, partially resolved, or fully resolved while retaining a good level of accuracy. Error estimates in each of these regimes are given for the method. A number of theoretical and numerical checks are furthermore performed to assess its physical fidelity. For a conservative force, the method is found to simulate particles with the correct Boltzmann equilibrium statistics. It is shown in three dimensions that the diffusion of immersed particles simulated with the method has the correct scaling in the physical parameters. The method is also shown to reproduce a well-known hydrodynamic effect of a Brownian particle in which the velocity autocorrelation function exhibits an algebraic (τ -3/2 ) decay for long times [B.J. Alder, T.E. Wainwright, Decay of the Velocity Autocorrelation Function, Phys. Rev. A 1(1) (1970) 18-21]. A few preliminary results are presented for more complex systems which demonstrate some potential application areas of the method. Specifically, we present simulations of osmotic effects of molecular dimers, worm-like chain polymer knots, and a basic model of a molecular motor immersed in fluid subject to a

  12. The scale dependence of single-nucleon shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Somà, V., E-mail: vittorio.soma@cea.fr [Centre de Saclay, IRFU/Service de Physique Nucléaire, 91191 Gif-sur-Yvette (France); Duguet, T. [Centre de Saclay, IRFU/Service de Physique Nucléaire, 91191 Gif-sur-Yvette (France); KU Leuven, Instituut voor Kern-en Stralingsfysica, 3001 Leuven (Belgium); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States); NSCL, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Hergert, H. [NSCL, Michigan State University, East Lansing, Michigan 48824-1321 (United States); The Ohio State University, Columbus, Ohio 43210 (United States); Holt, J. D. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)

    2015-10-15

    We address the scale dependence of (effective) single-particle energies, non-observable quantities that are commonly used for interpreting nuclear structure observables measured in experiments and computed in many-body theories. We first demonstrate their scale dependence on a formal level, making them intrinsically theoretical objects, before illustrating this point via ab initio calculations in the oxygen isotopes. Finally, we consider a modified definition of effective single-particle energy and investigate its running properties.

  13. Anomalous scaling in an age-dependent branching model

    OpenAIRE

    Keller-Schmidt, Stephanie; Tugrul, Murat; Eguíluz, Víctor M.; Hernández-García, Emilio; Klemm, Konstantin

    2015-01-01

    We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age $\\tau$ as $\\tau^{-\\alpha}$. Depending on the exponent $\\alpha$, the scaling of tree depth with tree size $n$ displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition ($\\alpha=1$) tree depth grows as $(\\log n)^2$. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus p...

  14. Influence of Growth Rate on Microstructural Length Scales in Directionally Solidified NiAl-Mo Hypo-Eutectic Alloy

    Science.gov (United States)

    Zhang, Jianfei; Ma, Xuewei; Ren, Huiping; Chen, Lin; Jin, Zili; Li, Zhenliang; Shen, Jun

    2016-01-01

    In this article, the Ni-46.1Al-7.8Mo (at.%) alloy was directionally solidified at different growth rates ranging from 15 μm/s to 1000 μm/s under a constant temperature gradient (334 K/cm). The dependence of microstructural length scales on the growth rate was investigated. The results show that, with the growth rate increasing, the primary dendritic arm spacings (PDAS) and secondary dendritic arm spacings (SDAS) decreased. There exists a large distribution range in PDAS under directional solidification conditions at a constant temperature gradient. The average PDAS and SDAS as a function of growth rate can be given as λ1 = 848.8967 V-0.4509 and λ2 = 64.2196 V-0.4140, respectively. In addition, a comparison of our results with the current theoretical models and previous experimental results has also been made.

  15. Chain length distributions in linear polyaddition proceeding in nano-scale small volumes without mass transfer

    Science.gov (United States)

    Szymanski, R.; Sosnowski, S.

    2017-01-01

    Computer simulations (Monte Carlo and numerical integration of differential equations) and theoretical analysis show that the statistical nature of polyaddition, both irreversible and reversible one, affects the way the macromolecules of different lengths are distributed among the small volume nano-reactors (droplets in this study) at any reaction time. The corresponding droplet distributions in respect to the number of reacting chains as well as the chain length distributions depend, for the given reaction time, on rate constants of polyaddition kp and depolymerization kd (reversible process), and the initial conditions: monomer concentration and the number of its molecules in a droplet. As a model reaction, a simple polyaddition process (M)1+(M)1 ⟶ ⟵ (M)2 , (M)i+(M)j ⟶ ⟵ (M)i+j was chosen, enabling to observe both kinetic and thermodynamic (apparent equilibrium constant) effects of a small number of reactant molecules in a droplet. The average rate constant of polymerization is lower than in a macroscopic system, depending on the average number of reactant molecules in a droplet. The apparent equilibrium constants of polymerization Ki j=[(M)i +j] ¯ /([(M)i] ¯ [(M)j] ¯ ) appear to depend on oligomer/polymer sizes as well as on the initial number of monomer molecules in a droplet. The corresponding equations, enabling prediction of the equilibrium conditions, were derived. All the analyzed effects are observed not only for ideally dispersed systems, i.e. with all droplets containing initially the same number of monomer (M)1 molecules, but also when initially the numbers of monomer molecules conform the Poisson distribution, expected for dispersions of reaction mixtures.

  16. Anomalous scaling in an age-dependent branching model.

    Science.gov (United States)

    Keller-Schmidt, Stephanie; Tuğrul, Murat; Eguíluz, Víctor M; Hernández-García, Emilio; Klemm, Konstantin

    2015-02-01

    We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age τ as τ(-α). Depending on the exponent α, the scaling of tree depth with tree size n displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition (α=1) tree depth grows as (logn)(2). This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus providing a theoretical support for age-dependent speciation and associating it to the occurrence of a critical point.

  17. Magneto-Induced ac Electrical Permittivity of Metal-Dielectric Composites with a Two Characteristic Length Scales Periodic Microstructure

    International Nuclear Information System (INIS)

    Strelniker, Y.M.; Bergman, D.J.

    1998-01-01

    A new effect was recently predicted in conducting composites that have a periodic microstructure: an induced strongly anisotropic dc magneto-resistance. This phenomenon is already verified on high mobility n-GaAs films. Here we discuss the possibility of observing analogous behavior in the ac electric permittivity of a metal-dielectric composite with a periodic microstructure in the presence of a strong magnetic field. We developed new analytical and numerical methods to treat the low-frequency magneto-optical properties in composite media with both disordered and periodic conducting micro-structures. Those methods allow us to study composites with inclusions of arbitrary shape (and arbitrary volume fraction) at arbitrarily strong magnetic field. This is exploited in order to calculate an effective dielectric tensor for this system as a function of applied magnetic field and ac frequency. We show that in a non-dilute metal-dielectric composite medium the magneto-plasma resonance and the cyclotron resonance depend upon both the applied magnetic field as well as on the geometric shape of the inclusion. Near such a resonance, it is possible to achieve large values for the ratio of the off-diagonal-to-diagonal electric permittivity tensor components, ε xy /ε xx , (since ε xx →0, while ε xy ≠0), which is analogous to similar ratio of the resistivity tensor components, ρ xy /ρ xx , in the case of dc magneto-transport problem. Motivated by this observation and by results of previous studies of dc magneto-transport in composite conductors, we then performed a numerical study of the ac magneto-electric properties of a particular metal-dielectric composite film with a periodic columnar microstructure which has a two characteristic length scales. The unit cell of such composite is prepared as follows: We placed the conducting square (in cross section) rods (first characteristic length scale) along the perimeter of the unit cell in order to create a dielectric host

  18. On the Evolution of the Integral Length Scale in the Wake of Wind Turbines and within Wind Farms

    Science.gov (United States)

    Liu, Huiwen; Jin, Yaqing; Hayat, Imran; Chamorro, Leonardo P.

    2017-11-01

    Wind tunnel experiments were performed to characterize the evolution of integral length scale in the wake of a single turbine, and around wind farms. Hotwire anemometry was used to obtain high-resolution measurements of the streamwise velocity fluctuation at various locations. Negligible and high freestream turbulence levels were considered in the case of single turbine. The integral length scale along the rotor axis is found to grow nearly linearly with distance independent of the incoming turbulence levels, and appears to reach the incoming level in the high turbulence case at about 35-40 rotor diameters downstream. In the wind farm, results suggest that the distribution of integral length scale can be roughly described by a power-law growth with distance within consecutive turbines. Approximately past the third row, the integral length scale appears to reach equilibrium of the spatial distribution.

  19. Statistical theory and transition in multiple-scale-lengths turbulence in plasmas

    International Nuclear Information System (INIS)

    Itoh, Sanae-I.; Itoh, Kimitaka

    2001-06-01

    The statistical theory of strong turbulence in inhomogeneous plasmas is developed for the cases where fluctuations with different scale-lengths coexist. Nonlinear interactions in the same kind of fluctuations as well as nonlinear interplay between different classes of fluctuations are kept in the analysis. Nonlinear interactions are modelled as turbulent drag, nonlinear noise and nonlinear drive, and a set of Langevin equations is formulated. With the help of an Ansatz of a large number of degrees of freedom with positive Lyapunov number, Langevin equations are solved and the fluctuation dissipation theorem in the presence of strong plasma turbulence has been derived. A case where two driving mechanisms (one for micro mode and the other for semi-micro mode) coexist is investigated. It is found that there are several states of fluctuations: in one state, the micro mode is excited and the semi-micro mode is quenched; in the other state, the semi-micro mode is excited, and the micro mode remains at finite but suppressed level. New type of turbulence transition is obtained, and a cusp type catastrophe is revealed. A phase diagram is drawn for turbulence which is composed of multiple classes of fluctuations. Influence of the inhomogeneous global radial electric field is discussed. A new insight is given for the physics of internal transport barrier. Finally, the nonlocal heat transport due to the long-wave-length fluctuations, which are noise-pumped by shorter-wave-length ones, is analyzed and the impact on transient transport problems is discussed. (author)

  20. Validity and factor structure of the bodybuilding dependence scale.

    Science.gov (United States)

    Smith, D; Hale, B

    2004-04-01

    To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders. Seventy two male competitive bodybuilders, 63 female competitive bodybuilders, 87 male non-competitive bodybuilders, and 63 non-competitive female bodybuilders completed the bodybuilding dependence scale (BDS), the exercise dependence questionnaire (EDQ), and the muscle dysmorphia inventory (MDI). Confirmatory factor analysis of the BDS supported a three factor model of bodybuilding dependence, consisting of social dependence, training dependence, and mastery dependence (Q = 3.16, CFI = 0.98, SRMR = 0.04). Internal reliability of all three subscales was high (Cronbach's alpha = 0.92, 0.92, and 0.93 respectively). Significant (pbodybuilders scored significantly (pbodybuilders. However, there were no significant sex differences on any of the BDS subscales (p>0.05). The three factor BDS appears to be a reliable and valid measure of bodybuilding dependence. Symptoms of bodybuilding dependence are more prevalent in competitive bodybuilders than non-competitive ones, but there are no significant sex differences in bodybuilding dependence.

  1. Length and temperature dependence of the mechanical properties of finite-size carbyne

    Science.gov (United States)

    Yang, Xueming; Huang, Yanhui; Cao, Bingyang; To, Albert C.

    2017-09-01

    Carbyne is an ideal one-dimensional conductor and the thinnest interconnection in an ultimate nano-device and it requires an understanding of the mechanical properties that affect device performance and reliability. Here, we report the mechanical properties of finite-size carbyne, obtained by a molecular dynamics simulation study based on the adaptive intermolecular reactive empirical bond order potential. To avoid confusion in assigning the effective cross-sectional area of carbyne, the value of the effective cross-sectional area of carbyne (4.148 Å2) was deduced via experiment and adopted in our study. Ends-constraints effects on the ultimate stress (maximum force) of the carbyne chains are investigated, revealing that the molecular dynamics simulation results agree very well with the experimental results. The ultimate strength, Young's Modulus and maximum strain of carbyne are rather sensitive to the temperature and all decrease with the temperature. Opposite tendencies of the length dependence of the overall ultimate strength and maximum strain of carbyne at room temperature and very low temperature have been found, and analyses show that this originates in the ends effect of carbyne.

  2. Conductance of Conjugated Molecular Wires: Length Dependence, Anchoring Groups, and Band Alignment

    DEFF Research Database (Denmark)

    Peng, Guowen; Strange, Mikkel; Thygesen, Kristian Sommer

    2009-01-01

    characteristic of tunneling through a barrier, G = Gc exp(−βL). For thiophene, pyrrole, and phenyl wires with thiol end-groups, we calculate decay constants (β) of 0.211, 0.257, and 0.264 Å−1, respectively, and contact conductances (Gc) of 1.25, 2.90, and 1.22G0, where G0 = 2e2/h is the conductance quantum....... In comparison, the corresponding values for amine-terminated thiophene are calculated to be β = 0.160 Å−1 and Gc = 0.038G0. These results show that (1) the contact resistance is mainly determined by the anchoring group and (2) the decay constant, which determines the conductance in the long wire limit......The conductance of π-conjugated molecular wires bonded to gold electrodes at zero bias is studied using density functional theory combined with nonequilibrium Green’s function method. For all systems considered, we find that the conductance length dependence follows the simple exponential law...

  3. Fabrication of Cu-induced networks of linear nanostructures on different length scales

    International Nuclear Information System (INIS)

    Adelung, R.; Hartung, W.; Ernst, F.

    2002-01-01

    Scanning electron microscopy and atomic force microscopy revealed that the deposition Cu onto VSe 2 substrates in ultra-high vacuum leads to the self-organized formation of linear nanostructures, nanowires and nanotunnels, on the substrate surface. The nanowires and nanotunnels are approximately equi-axed and form networks with a mesh width much larger than their diameter. Surprisingly, systematic increase of the Cu coverage studied here does not simply increase the thickness of the nanowires and nanotunnels, but induces the formation of further, distinct networks with increased feature size and increased mesh width. At very high Cu coverages, eventually, we obtained a hierarchy of apparently independent nanowire and nanotunnel networks on different length scales. A model is presented for the micromechanism that leads to this complex arrangement of nanostructures

  4. Advancing the speed, sensitivity and accuracy of biomolecular detection using multi-length-scale engineering

    Science.gov (United States)

    Kelley, Shana O.; Mirkin, Chad A.; Walt, David R.; Ismagilov, Rustem F.; Toner, Mehmet; Sargent, Edward H.

    2014-12-01

    Rapid progress in identifying disease biomarkers has increased the importance of creating high-performance detection technologies. Over the last decade, the design of many detection platforms has focused on either the nano or micro length scale. Here, we review recent strategies that combine nano- and microscale materials and devices to produce large improvements in detection sensitivity, speed and accuracy, allowing previously undetectable biomarkers to be identified in clinical samples. Microsensors that incorporate nanoscale features can now rapidly detect disease-related nucleic acids expressed in patient samples. New microdevices that separate large clinical samples into nanocompartments allow precise quantitation of analytes, and microfluidic systems that utilize nanoscale binding events can detect rare cancer cells in the bloodstream more accurately than before. These advances will lead to faster and more reliable clinical diagnostic devices.

  5. Hierarchical self-assembly of two-length-scale multiblock copolymers

    International Nuclear Information System (INIS)

    Brinke, Gerrit ten; Loos, Katja; Vukovic, Ivana; Du Sart, Gerrit Gobius

    2011-01-01

    The self-assembly in diblock copolymer-based supramolecules, obtained by hydrogen bonding short side chains to one of the blocks, as well as in two-length-scale linear terpolymers results in hierarchical structure formation. The orientation of the different domains, e.g. layers in the case of a lamellar-in-lamellar structure, is determined by the molecular architecture, graft-like versus linear, and the relative magnitude of the interactions involved. In both cases parallel and perpendicular arrangements have been observed. The comb-shaped supramolecules approach is ideally suited for the preparation of nanoporous structures. A bicontinuous morphology with the supramolecular comb block forming the channels was finally achieved by extending the original approach to suitable triblock copolymer-based supramolecules.

  6. Multi-length scale porous polymer films from hypercrosslinked breath figure arrays.

    Science.gov (United States)

    Ding, Lei; Zhang, Aijuan; Li, Wenqing; Bai, Hua; Li, Lei

    2016-01-01

    Multi-length scale porous polymer (MLSPP) films were fabricated using commercially available polystyrene (PS) via static breath figure (BF) process and sequent hypercrosslinking reaction. One level of ordered pores in microscale were introduced using static BF process, and the other level in nanoscale were produced by the sequent Friedel-Crafts hypercrosslinking reaction. The chemical structure of the PS MLSPP film was investigated by Fourier transformation infrared spectrometry and solid state nuclear magnetic resonance, and the morphology of the film was observed with electron microscopes. The MLSPP films showed large specific surface areas and excellent chemical and thermal stabilities, owing to the micropores and the crosslinked chemical structure produced by the Friedel-Crafts reaction. The methodology reported in this paper is a template-free, low cost and general strategy for the preparation of MLSPP films, which has potential applications in the areas of environment and energy. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Accurate switching intensities and length scales in quasi-phase-matched materials

    DEFF Research Database (Denmark)

    Bang, Ole; Graversen, Torben Winther; Corney, Joel Frederick

    2001-01-01

    We consider unseeded typeI second-harmonic generation in quasi-phase-matched quadratic nonlinear materials and derive an accurate analytical expression for the evolution of the average intensity. The intensity- dependent nonlinear phase mismatch that is due to the cubic nonlinearity induced...... by quasi phase matching is found. The equivalent formula for the intensity of maximum conversion, the crossing of which changes the one-period nonlinear phase shift of the fundamental abruptly by p , corrects earlier estimates [Opt.Lett. 23, 506 (1998)] by a factor of 5.3. We find the crystal lengths...... that are necessary to obtain an optimal flat phase versus intensity response on either side of this separatrix intensity....

  8. [Development of a New Scale for Gauging Smartphone Dependence].

    Science.gov (United States)

    Toda, Masahiro; Nishio, Nobuhiro; Takeshita, Tatsuya

    2015-01-01

    We designed a scale to gauge smartphone dependence and assessed its reliability and validity. A prototype self-rating smartphone-dependence scale was tested on 133 medical students who use smartphones more frequently than other devices to access web pages. Each response was scored on a Likert scale (0, 1, 2, 3), with higher scores indicating greater dependence. To select items for the final scale, exploratory factor analysis was conducted. On the basis of factor analysis results, we designed the Wakayama Smartphone-Dependence Scale (WSDS) comprising 21 items with 3 subscales: immersion in Internet communication; using a smartphone for extended periods of time and neglecting social obligations and other tasks; using a smartphone while doing something else and neglect of etiquette. Our analysis confirmed the validity of the different elements of the WSDS: the reliability coefficient (Cronbach's alpha) values of all subscales and total WSDS were from 0.79 to 0.83 and 0.88, respectively. These findings suggest that the WSDS is a useful tool for rating smartphone dependence.

  9. Zebrafish brain mapping--standardized spaces, length scales, and the power of N and n.

    Science.gov (United States)

    Hunter, Paul R; Hendry, Aenea C; Lowe, Andrew S

    2015-06-01

    Mapping anatomical and functional parameters of the zebrafish brain is moving apace. Research communities undertaking such studies are becoming ever larger and more diverse. The unique features, tools, and technologies associated with zebrafish are propelling them as the 21st century model organism for brain mapping. Uniquely positioned as a vertebrate model system, the zebrafish enables imaging of anatomy and function at different length scales from intraneuronal compartments to sparsely distributed whole brain patterns. With a variety of diverse and established statistical modeling and analytic methods available from the wider brain mapping communities, the richness of zebrafish neuroimaging data is being realized. The statistical power of population observations (N) within and across many samples (n) projected onto a standardized space will provide vast databases for data-driven biological approaches. This article reviews key brain mapping initiatives at different levels of scale that highlight the potential of zebrafish brain mapping. By way of introduction to the next wave of brain mappers, an accessible introduction to the key concepts and caveats associated with neuroimaging are outlined and discussed. © 2014 Wiley Periodicals, Inc.

  10. Evaluating the accuracy of finite element models at reduced length scales

    Science.gov (United States)

    Kemp, Connor

    Finite element models are used frequently in both engineering and scientific research. While they can provide useful information as to the performance of materials, as length scales are decreased more sophisticated model descriptions are required. It is also important to develop methods by which existing models may be verified against experimental findings. The present study evaluates the ability of various finite element models to predict materials behaviour at length scales ranging from several microns to tens of nanometers. Considering this motivation, this thesis is provided in manuscript form with the bulk of material coming from two case studies. Following an overview of relevant literature in Chapter 2, Chapter 3 considers the nucleation of delta-zirconium hydrides in a Zircaloy-2 matrix. Zirconium hydrides are an important topic in the nuclear industry as they form a brittle phase which leads to delayed hydride cracking during reactor start-up and shut-down. Several FE models are used to compare present results with literature findings and illustrate the weaknesses of standard FE approaches. It is shown that standard continuum techniques do not sufficiently capture the interfacial effects of an inclusion-matrix system. By using nano-scale material descriptions, nucleation lattice strains are obtained which are in good agreement with previous experimental studies. The motivation for Chapter 4 stems from a recognized need to develop a method for modeling corrosion behaviour of materials. Corrosion is also an issue for reactor design and an ability to predict failure points is needed. Finite element models could be used for this purpose, provided model accuracy is verified first. In Chapter 4 a technique is developed which facilitates the extraction of sub-micron resolution strain data from correlation images obtained during in-situ tensile deformation. By comparing image correlation results with a crystal plasticity finite element code it is found that good

  11. The length dependence of the series elasticity of pig bladder smooth muscle

    NARCIS (Netherlands)

    R. van Mastrigt (Ron)

    1988-01-01

    textabstractStrips of urinary bladder smooth muscle were subjected to a series of quick release measurements. Each measurement consisted of several releases and resets to the original length, made during one contraction. The complete length-force characteristic of series elasticity was quantified by

  12. Failure analysis of fuel cell electrodes using three-dimensional multi-length scale X-ray computed tomography

    Science.gov (United States)

    Pokhrel, A.; El Hannach, M.; Orfino, F. P.; Dutta, M.; Kjeang, E.

    2016-10-01

    X-ray computed tomography (XCT), a non-destructive technique, is proposed for three-dimensional, multi-length scale characterization of complex failure modes in fuel cell electrodes. Comparative tomography data sets are acquired for a conditioned beginning of life (BOL) and a degraded end of life (EOL) membrane electrode assembly subjected to cathode degradation by voltage cycling. Micro length scale analysis shows a five-fold increase in crack size and 57% thickness reduction in the EOL cathode catalyst layer, indicating widespread action of carbon corrosion. Complementary nano length scale analysis shows a significant reduction in porosity, increased pore size, and dramatically reduced effective diffusivity within the remaining porous structure of the catalyst layer at EOL. Collapsing of the structure is evident from the combination of thinning and reduced porosity, as uniquely determined by the multi-length scale approach. Additionally, a novel image processing based technique developed for nano scale segregation of pore, ionomer, and Pt/C dominated voxels shows an increase in ionomer volume fraction, Pt/C agglomerates, and severe carbon corrosion at the catalyst layer/membrane interface at EOL. In summary, XCT based multi-length scale analysis enables detailed information needed for comprehensive understanding of the complex failure modes observed in fuel cell electrodes.

  13. Length Scales of Reactive Transport in Basalt: Hydrothermal Flow-through Experiments and Anhydrite Precipitation

    Science.gov (United States)

    Los, C.; Kahl, W. A.; Bach, W.

    2017-12-01

    Hydrothermal circulation is a large contributor to mass and heat exchange between oceanic lithosphere and hydrosphere. Cold, unaltered seawater infiltrates in the shallow basaltic crust, leading to sulfate precipitation and clogging of fluid pathways. Anhydrite (CaSO4) veins are common in hydrothermal discharge zones, where entrained seawater is heated and anhydrite quickly forms. Anhydrite is also found in hydrothermal recharge zones, but questions regarding time and length scale in this setting remain. To investigate element transport and anhydrite precipitation we have conducted flow-through experiments using a gypsum-undersaturated CaSO4 solution in pre-fractured basalt at 95, 110 and 140°C. Each run was terminated upon clogging of the input tubes, which took 2-8 weeks. The rock core was scanned before the run and weekly during the experiment using X-ray tomography. Fluid major element chemistry was analyzed using ICP-OES. Geochemical modeling with the software package EQ3/6 showed that the starting solution became supersaturated in anhydrite (SI=IAP/K of 2.5 or higher) in all cases upon heating to the experimental temperature. The software CRUNCH FLOW was used to analyze chemical effects over the length of the core (3cm). The 95°C run and a first run at 110°C did not show any anhydrite. Instead, hematite rosettes and sulfur-bearing (maximum of 1 wt.%) globular Fe-rich structures were present. Tomography images showed that fractures and pores were slightly thinned over the whole core length. Single pores in a second 110°C run and fractures in the 140°C run did show formation of anhydrite and quartz close to the outlet. CRUNCH FLOW modeling predicts the observed release of Mg, Fe, Si, Al, Na and K due to silicate dissolution close to the inlet, while the outlet area should contain some anhydrite. No other sulfur-bearing phases were predicted. The results of this study show that anhydrite needs a large supersaturation (SI>2.5) to precipitate at temperatures

  14. Ataxia rating scales are age-dependent in healthy children.

    Science.gov (United States)

    Brandsma, Rick; Spits, Anne H; Kuiper, Marieke J; Lunsing, Roelinka J; Burger, Huibert; Kremer, Hubertus P; Sival, Deborah A

    2014-06-01

    To investigate ataxia rating scales in children for reliability and the effect of age and sex. Three independent neuropaediatric observers cross-sectionally scored a set of paediatric ataxia rating scales in a group of 52 healthy children (26 males, 26 females) aged 4 to 16 years (mean age 10y 5mo SD 3y 11mo). The investigated scales involved the commonly applied International Cooperative Ataxia Rating Scale (ICARS), the Scale for Assessment and Rating of Ataxia (SARA), the Brief Ataxia Rating Scale (BARS), and PEG-board tests. We investigated the interrelatedness between individual ataxia scales, the influence of age and sex, inter- and intra-observer agreement, and test-retest reliability. Spearman's rank correlations revealed strong correlations between ICARS, SARA BARS, and PEG-board test (all prating scales are reliable, but should include age-dependent interpretation in children up to 12 years of age. To enable longitudinal interpretation of quantitative ataxia rating scales in children, European paediatric normative values are necessary. © 2014 Mac Keith Press.

  15. Instantaneous equations for multiphase flow in porous media without length-scale restrictions using a non-local averaging volume

    International Nuclear Information System (INIS)

    Espinosa-Paredes, Gilberto

    2010-01-01

    The aim of this paper is to propose a framework to obtain a new formulation for multiphase flow conservation equations without length-scale restrictions, based on the non-local form of the averaged volume conservation equations. The simplification of the local averaging volume of the conservation equations to obtain practical equations is subject to the following length-scale restrictions: d << l << L, where d is the characteristic length of the dispersed phases, l is the characteristic length of the averaging volume, and L is the characteristic length of the physical system. If the foregoing inequality does not hold, or if the scale of the problem of interest is of the order of l, the averaging technique and therefore, the macroscopic theories of multiphase flow should be modified in order to include appropriate considerations and terms in the corresponding equations. In these cases the local form of the averaged volume conservation equations are not appropriate to describe the multiphase system. As an example of the conservation equations without length-scale restrictions, the natural circulation boiling water reactor was consider to study the non-local effects on the thermal-hydraulic core performance during steady-state and transient behaviors, and the results were compared with the classic local averaging volume conservation equations.

  16. An international psychometric testing of the Care Dependency Scale

    NARCIS (Netherlands)

    Dijkstra, A.; Brown, L.; Havens, B.; Romeren, T.I.; Zanotti, R.; Dassen, T.; van den Heuvel, W.

    In an international study, psychometric properties of the Care Dependency Scale (CDS) were examined by analysing data gathered in Dutch, Canadian, Italian and Norwegian nursing homes. For that purpose, from these countries a convenience sample was developed consisting of 525 patients with dementia.

  17. Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial

    Directory of Open Access Journals (Sweden)

    Riaz U. Ahmed

    2014-11-01

    Full Text Available This letter presents the possibility of energy scavenging (ES utilizing the physics of acousto-elastic metamaterial (AEMM at low frequencies (<∼3KHz. It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester, simultaneously. AEMM’s are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ∼3 KHz, maximum power in the micro Watts (∼35µW range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ∼10µW – ∼90µW between 0.2 KHz and 1.5 KHz acoustic frequencies.

  18. Genetic variability of the stable fly assessed on a global scale using amplified fragment length polymorphism.

    Science.gov (United States)

    Kneeland, Kathleen M; Skoda, Steven R; Foster, John E

    2016-10-01

    The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is a blood-feeding, economically important pest of animals and humans worldwide. Improved management strategies are essential and their development would benefit from studies on genetic diversity of stable flies. Especially if done on a global scale, such research could generate information necessary for the development and application of more efficient control methods. Herein we report on a genetic study of stable flies using amplified fragment length polymorphism, with samples of 10-40 individuals acquired from a total of 25 locations in the Nearctic, Neotropic, Palearctic, Afrotropic and Australasian biogeographical regions. We hypothesized that genetic differentiation would exist across geographical barriers. Although FST (0.33) was moderately high, the GST (0.05; representing genetic diversity between individuals) was very low; Nm values (representing gene flow) were high (9.36). The mismatch distribution and tests of neutrality suggested population expansion, with no genetic differentiation between locations. The analysis of molecular variance (AMOVA) results showed the majority of genetic diversity was within groups. The mantel test showed no correlation between geographic and genetic distance; this strongly supports the AMOVA results. These results suggest that stable flies did not show genetic differentiation but are panmictic, with no evidence of isolation by distance or across geographical barriers. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  19. Extending the length and time scales of Gram–Schmidt Lyapunov vector computations

    International Nuclear Information System (INIS)

    Costa, Anthony B.; Green, Jason R.

    2013-01-01

    Lyapunov vectors have found growing interest recently due to their ability to characterize systems out of thermodynamic equilibrium. The computation of orthogonal Gram–Schmidt vectors requires multiplication and QR decomposition of large matrices, which grow as N 2 (with the particle count). This expense has limited such calculations to relatively small systems and short time scales. Here, we detail two implementations of an algorithm for computing Gram–Schmidt vectors. The first is a distributed-memory message-passing method using Scalapack. The second uses the newly-released MAGMA library for GPUs. We compare the performance of both codes for Lennard–Jones fluids from N=100 to 1300 between Intel Nahalem/Infiniband DDR and NVIDIA C2050 architectures. To our best knowledge, these are the largest systems for which the Gram–Schmidt Lyapunov vectors have been computed, and the first time their calculation has been GPU-accelerated. We conclude that Lyapunov vector calculations can be significantly extended in length and time by leveraging the power of GPU-accelerated linear algebra

  20. Bifurcation and phase diagram of turbulence constituted from three different scale-length modes

    International Nuclear Information System (INIS)

    Itoh, S.-I.; Kitazawa, A.; Yagi, M.; Itoh, K.

    2002-04-01

    Cases where three kinds of fluctuations having the different typical scale-lengths coexist are analyzed, and the statistical theory of strong turbulence in inhomogeneous plasmas is developed. Statistical nonlinear interactions between fluctuations are kept in the analysis as the renormalized drag, statistical noise and the averaged drive. The nonlinear interplay through them induces a quenching or suppressing effect, even if all the modes are unstable when they are analyzed independently. Variety in mode appearance takes place: one mode quenches the other two modes, or one mode is quenched by the other two modes, etc. The bifurcation of turbulence is analyzed and a phase diagram is drawn. Phase diagrams with cusp type catastrophe and butterfly type catastrophe are obtained. The subcritical bifurcation is possible to occur through the nonlinear interplay, even though each one is supercritical turbulence when analyzed independently. Analysis reveals that the nonlinear stability boundary (marginal point) and the amplitude of each mode may substantially shift from the conventional results of independent analyses. (author)

  1. Cellular adaptation to biomechanical stress across length scales in tissue homeostasis and disease.

    Science.gov (United States)

    Gilbert, Penney M; Weaver, Valerie M

    2017-07-01

    Human tissues are remarkably adaptable and robust, harboring the collective ability to detect and respond to external stresses while maintaining tissue integrity. Following injury, many tissues have the capacity to repair the damage - and restore form and function - by deploying cellular and molecular mechanisms reminiscent of developmental programs. Indeed, it is increasingly clear that cancer and chronic conditions that develop with age arise as a result of cells and tissues re-implementing and deregulating a selection of developmental programs. Therefore, understanding the fundamental molecular mechanisms that drive cell and tissue responses is a necessity when designing therapies to treat human conditions. Extracellular matrix stiffness synergizes with chemical cues to drive single cell and collective cell behavior in culture and acts to establish and maintain tissue homeostasis in the body. This review will highlight recent advances that elucidate the impact of matrix mechanics on cell behavior and fate across these length scales during times of homeostasis and in disease states. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Revisiting the Scale Length-μ0 Plane and the Freeman Law in the Local Universe

    Science.gov (United States)

    Fathi, Kambiz

    2010-10-01

    We have used Virtual Observatory technology to analyze the disk scale length rd and central surface brightness μ0 for a sample of 29,955 bright disk galaxies from the Sloan Digital Sky Survey. We use the results in the r band and revisit the relation between these parameters and the galaxy morphology, and find the average value langμ0rang = 20.2 ± 0.7 mag arcsec-2. We confirm that late-type spirals populate the lower left corner of the rd -μ0 plane and that the early and intermediate spirals are mixed in this diagram, with disky ellipticals at the top left corner. We further investigate the Freeman Law and confirm that it indeed defines an upper limit for μ0 in bright disk galaxies with r mag = 6) have fainter central surface brightness. Our results are based on a volume-corrected sample of galaxies in the local universe (z numerical simulations of galaxy formation and evolution.

  3. Surface-immobilized hydrogel patterns on length scales from micrometer to nanometer

    Science.gov (United States)

    Zeira, Assaf

    The present work concentrates on the study of pattern generation and transfer processes of monolayer covered surfaces, deriving from the basic working concept of Constructive Lithography. As an advancement of constructive lithography, we developed a direct, one-step printing (contact electrochemical printing, CEP) and replication (contact electrochemical replication, CER) of hydrophilic organic monolayer patterns surrounded by a hydrophobic monolayer background. In addition, we present a process of transfer of metal between two contacting solid surfaces to predefined monolayer template pattern sites (contact electrochemical transfer, CET). This thesis shows that CEP, CER, and CET may be implemented under a variety of different experimental conditions, regardless of whether the initial "master" pattern was created by a parallel (fast) or serial (slow) patterning process. CEP and CER also posses the unique attractive property that each replica may equally function as master stamp in the fabrication of additional replicas. Moreover, due to a mechanism of selfcorrection patterned surfaces produced these process are often free of defects that the initial "master" stamp may had. We finally show that the electrochemical patterning of OTS monolayers on silicon can be further extended to flexible polymeric substrate materials as well as to a variety of chemical manipulations, allowing the fabrication of tridimensional (3D) composite structures made on the basis of readily available OTS compound. The results obtained suggest that such contact electrochemical processes could be used to rapidly generate multiple copies of surface patterns spanning variable length scales, this basic approach being applicable to rigid as well as flexible substrate materials.

  4. Muscle activation and blood flow do not explain the muscle length-dependent variation in quadriceps isometric endurance

    NARCIS (Netherlands)

    Kooistra, R.D.; de Ruiter, C.J.; de Haan, A.

    2005-01-01

    We investigated the role of central activation in muscle length-dependent endurance. Central activation ratio (CAR) and rectified surface electromyogram (EMG) were studied during fatigue of isometric contractions of the knee extensors at 30 and 90° knee angles (full extension = 0°). Subjects (n = 8)

  5. The Effect of Physiotherapy on Ventilatory Dependency and the Length of Stay in an Intensive Care Unit

    Science.gov (United States)

    Malkoc, Mehtap; Karadibak, Didem; Yldrm, Yucel

    2009-01-01

    The aim of this study was to assess the effect of physiotherapy on ventilator dependency and lengths of intensive care unit (ICU) stay. Patients were divided into two groups. The control group, which received standard nursing care, was a retrospective chart review. The data of control patients who were not receiving physiotherapy were obtained…

  6. Increment definitions for scale-dependent analysis of stochastic data.

    Science.gov (United States)

    Waechter, Matthias; Kouzmitchev, Alexei; Peinke, Joachim

    2004-11-01

    It is common for scale-dependent analysis of stochastic data to use the increment Delta(t,r) =xi(t+r)-xi(t) of a data set xi(t) as a stochastic measure, where r denotes the scale. For joint statistics of Delta(t,r) and Delta(t, r') the question of how to nest the increments on different scales r, r' is investigated. Here we show that in some cases spurious correlations between scales can be introduced by the common left-justified definition. The consequences for a Markov process are discussed. These spurious correlations can be avoided by an appropriate nesting of increments. We demonstrate this effect for different data sets and show how it can be detected and quantified. The problem allows to propose a unique method to distinguish between experimental data generated by a noiselike or a Langevin-like random-walk process, respectively.

  7. Diffusion effects on volume-selective NMR at small length scales

    International Nuclear Information System (INIS)

    Gaedke, Achim

    2009-01-01

    In this thesis, the interplay between diffusion and relaxation effects in spatially selective NMR experiments at short length scales is explored. This is especially relevant in the context of both conventional and mechanically detected MRI at (sub)micron resolution in biological specimens. Recent results on selectively excited very thin slices showed an in-slice-magnetization recovery orders of magnitude faster than the longitudinal relaxation time T1. However, those experiments were run on fully relaxed samples while MRI and especially mechanically detected NMR experiments are typically run in a periodic fashion with repetition times far below T1. The main purpose of this work therefore was to extend the study of the interplay between diffusion and longitudinal relaxation to periodic excitations. In some way, this is inverse phenomenon to the DESIRE (Diffusive Enhancement of SIgnal and REsolution) approach, proposed 1992 by Lauterbur. Experiments on periodically excited thin slices were carried out at a dedicated static field gradient cryomagnet with magnetic field gradients up to 180 T/m. In order to obtain plane slices, an appropriate isosurface of the gradient magnet had to be identified. It was found at a field of 3.8 T with a gradient of 73 T/m. In this field, slices down to a thickness of 3.2 μm could be excited. The detection of the NMR signal was done using FIDs instead of echoes as the excitation bandwidth of those thin slices is sufficiently small to observe FIDs which are usually considered to be elusive to detection in such strong static field gradients. A simulation toolbox based on the full Bloch-Torrey-equation was developed to describe the excitation and the formation of NMR signals under those unusual conditions as well as the interplay of diffusion and magnetization recovery. Both the experiments and the simulations indicate that diffusion effects lead to a strongly enhanced magnetization modulation signal also under periodic excitation

  8. Scale-dependent interactions and community structure on cobble beaches.

    Science.gov (United States)

    van de Koppel, Johan; Altieri, Andrew H; Silliman, Brian R; Bruno, John F; Bertness, Mark D

    2006-01-01

    Recent theory suggests that scale-dependent interaction between facilitation and competition can generate spatial structure in ecological communities. The application of this hypothesis, however, has been limited to systems with little underlying heterogeneity. We evaluated this prediction in a plant community along an intertidal stress gradient on cobble beaches in Rhode Island, USA. Prior studies have shown that Spartina alterniflora facilitates a forb-dominated community higher in the intertidal by modifying the shoreline environment. We tested the hypothesis that, at a smaller scale, Spartina competitively excludes forb species, explaining their marked absence within the lower Spartina zone. Transplant experiments showed forb species grow significantly better in the Spartina zone when neighbours were removed. Removal of the Spartina canopy led to a massive emergence of annual forbs, showing that competition limits local occupation. These findings indicate that interaction of large-scale facilitation and small-scale competition drives plant zonation on cobble beaches. This study is the first to provide empirical evidence of scale-dependent interactions between facilitation and competition spatially structuring communities in heterogeneous environments.

  9. Magnetic field dependence of the magnon spin diffusion length in the magnetic insulator yttrium iron garnet

    NARCIS (Netherlands)

    Cornelissen, L. J.; van Wees, B. J.

    2016-01-01

    We investigated the effect of an external magnetic field on the diffusive spin transport by magnons in the magnetic insulator Y3Fe5O12, using a nonlocal magnon transport measurement geometry. We observed a decrease in magnon spin diffusion length lambda(m) for increasing field strengths, where

  10. Anomalous length dependence of conductance of aromatic nanoribbons with amine anchoring groups

    KAUST Repository

    Bilić, Ante

    2012-09-06

    Two sets of aromatic nanoribbons, based around a common hexagonal scaffolding, with single and dual terminal amine groups have been considered as potential molecular wires in a junction formed by gold leads. Charge transport through the two-terminal device has been modeled using density functional theory (with and without self-interaction correction) and the nonequilibrium Green\\'s function method. The effects of wire length, multiple terminal contacts, and pathways across the junction have been investigated. For nanoribbons with the oligopyrene motif and conventional single amine terminal groups, an increase in the wire length causes an exponential drop in the conductance. In contrast, for the nanoribbons with the oligoperylene motif and dual amine anchoring groups the predicted conductance rises with the wire length over the whole range of investigated lengths. Only when the effects of self-interaction correction are taken into account, the conductance of the oligoperylene ribbons exhibits saturation for longer members of the series. The oligoperylene nanoribbons, with dual amine groups at both terminals, show the potential to fully harness the highly conjugated system of π molecular orbitals across the junction. © 2012 American Physical Society.

  11. Binary self-assembled monolayers: Apparent exponential dependence of resistance on average molecular length

    NARCIS (Netherlands)

    Katsouras, I.; Geskin, V.; Kronemeijer, A.J.; Blom, P.W.M.; Leeuw, D.M. de

    2011-01-01

    We investigate the electrical transport through mixed self-assembled monolayers of alkanemonothiols and alkanedithiols in large-area molecular junctions. To disentangle the role of the molecular length and the interfacial composition, monothiol-monothiol, dithiol-dithiol, and monothiol-dithiol

  12. Binary self-assembled monolayers : Apparent exponential dependence of resistance on average molecular length

    NARCIS (Netherlands)

    Katsouras, Ilias; Geskin, Victor; Kronemeijer, Auke J.; Blom, Paul W. M.; de Leeuw, Dago M.

    We investigate the electrical transport through mixed self-assembled monolayers of alkanemonothiols and alkanedithiols in large-area molecular junctions. To disentangle the role of the molecular length and the interfacial composition, monothiol-monothiol, dithiol-dithiol, and monothiol-dithiol

  13. Quantitative atom probe analysis of nanostructure containing clusters and precipitates with multiple length scales

    International Nuclear Information System (INIS)

    Marceau, R.K.W.; Stephenson, L.T.; Hutchinson, C.R.; Ringer, S.P.

    2011-01-01

    A model Al-3Cu-(0.05 Sn) (wt%) alloy containing a bimodal distribution of relatively shear-resistant θ' precipitates and shearable GP zones is considered in this study. It has recently been shown that the addition of the GP zones to such microstructures can lead to significant increases in strength without a decrease in the uniform elongation. In this study, atom probe tomography (APT) has been used to quantitatively characterise the evolution of the GP zones and the solute distribution in the bimodal microstructure as a function of applied plastic strain. Recent nuclear magnetic resonance (NMR) analysis has clearly shown strain-induced dissolution of the GP zones, which is supported by the current APT data with additional spatial information. There is significant repartitioning of Cu from the GP zones into the solid solution during deformation. A new approach for cluster finding in APT data has been used to quantitatively characterise the evolution of the sizes and shapes of the Cu containing features in the solid solution solute as a function of applied strain. -- Research highlights: → A new approach for cluster finding in atom probe tomography (APT) data has been used to quantitatively characterise the evolution of the sizes and shapes of the Cu containing features with multiple length scales. → In this study, a model Al-3Cu-(0.05 Sn) (wt%) alloy containing a bimodal distribution of relatively shear-resistant θ' precipitates and shearable GP zones is considered. → APT has been used to quantitatively characterise the evolution of the GP zones and the solute distribution in the bimodal microstructure as a function of applied plastic strain. → It is clearly shown that there is strain-induced dissolution of the GP zones with significant repartitioning of Cu from the GP zones into the solid solution during deformation.

  14. Ion-beam induced transformations in nanoscale multilayers: Evolution of clusters with preferred length scales

    Science.gov (United States)

    Bera, S.; Satpati, B.; Goswami, D. K.; Bhattacharjee, K.; Satyam, P. V.; Dev, B. N.

    2006-04-01

    Ion-irradiation-induced modifications of a periodic Pt/C multilayer system containing a small amount of Fe have been analyzed by transmission electron microscopy and grazing incidence x-ray diffraction (GIXRD) studies. The multilayer stack with 16 Pt/C layer pairs (period of 4.23 nm) was fabricated on a glass substrate. A 2 MeV Au2+ ion beam was rastered on the sample to obtain uniformly irradiated strips with fluences from 1×1014 to 1×1015 ions/cm2. Ion irradiation has been found to cause preferential migration of Fe towards Pt layers [Bera et al., Nucl. Instrum. Methods Phys. Res. B 212, 530 (2003)]. Cross-sectional transmission electron microscopy (XTEM) shows considerable atomic redistribution for irradiation at the highest ion fluence (1×1015 ions/cm2). This structure is composed of small clusters. Phase separation and cluster formation processes are discussed. Periodic multilayers have periodicity only in the direction normal to the multilayer surface. However, Fourier transform (FT) of the XTEM images of the sample irradiated at the highest fluence shows extra off-normal Fourier components of superlattice periodicities arising due to ion irradiation. These extra spots in the FT are due to preferential length scales in intercluster separation in three dimensions. With a proper understanding of this phenomenon it may be possible to fabricate useful three-dimensional self-assembled structures of nanoclusters. Our high resolution transmission electron microscopy and GIXRD results reveal the formation of an FePt alloy. As FePt is a magnetic alloy, our observation raises the possibility of fabrication of ion-beam induced magnetic nanocluster lattices.

  15. Ion-beam induced transformations in nanoscale multilayers: Evolution of clusters with preferred length scales

    International Nuclear Information System (INIS)

    Bera, S.; Satpati, B.; Goswami, D. K.; Bhattacharjee, K.; Satyam, P. V.; Dev, B. N.

    2006-01-01

    Ion-irradiation-induced modifications of a periodic Pt/C multilayer system containing a small amount of Fe have been analyzed by transmission electron microscopy and grazing incidence x-ray diffraction (GIXRD) studies. The multilayer stack with 16 Pt/C layer pairs (period of 4.23 nm) was fabricated on a glass substrate. A 2 MeV Au 2+ ion beam was rastered on the sample to obtain uniformly irradiated strips with fluences from 1x10 14 to 1x10 15 ions/cm 2 . Ion irradiation has been found to cause preferential migration of Fe towards Pt layers [Bera et al., Nucl. Instrum. Methods Phys. Res. B 212, 530 (2003)]. Cross-sectional transmission electron microscopy (XTEM) shows considerable atomic redistribution for irradiation at the highest ion fluence (1x10 15 ions/cm 2 ). This structure is composed of small clusters. Phase separation and cluster formation processes are discussed. Periodic multilayers have periodicity only in the direction normal to the multilayer surface. However, Fourier transform (FT) of the XTEM images of the sample irradiated at the highest fluence shows extra off-normal Fourier components of superlattice periodicities arising due to ion irradiation. These extra spots in the FT are due to preferential length scales in intercluster separation in three dimensions. With a proper understanding of this phenomenon it may be possible to fabricate useful three-dimensional self-assembled structures of nanoclusters. Our high resolution transmission electron microscopy and GIXRD results reveal the formation of an FePt alloy. As FePt is a magnetic alloy, our observation raises the possibility of fabrication of ion-beam induced magnetic nanocluster lattices

  16. In situ spatiotemporal mapping of flow fields around seeded stem cells at the subcellular length scale.

    Directory of Open Access Journals (Sweden)

    Min Jae Song

    2010-09-01

    Full Text Available A major hurdle to understanding and exploiting interactions between the stem cell and its environment is the lack of a tool for precise delivery of mechanical cues concomitant to observing sub-cellular adaptation of structure. These studies demonstrate the use of microscale particle image velocimetry (μ-PIV for in situ spatiotemporal mapping of flow fields around mesenchymal stem cells, i.e. murine embryonic multipotent cell line C3H10T1/2, at the subcellular length scale, providing a tool for real time observation and analysis of stem cell adaptation to the prevailing mechanical milieu. In the absence of cells, computational fluid dynamics (CFD predicts flow regimes within 12% of μ-PIV measures, achieving the technical specifications of the chamber and the flow rates necessary to deliver target shear stresses at a particular height from the base of the flow chamber. However, our μ-PIV studies show that the presence of cells per se as well as the density at which cells are seeded significantly influences local flow fields. Furthermore, for any given cell or cell seeding density, flow regimes vary significantly along the vertical profile of the cell. Hence, the mechanical milieu of the stem cell exposed to shape changing shear stresses, induced by fluid drag, varies with respect to proximity of surrounding cells as well as with respect to apical height. The current study addresses a previously unmet need to predict and observe both flow regimes as well as mechanoadaptation of cells in flow chambers designed to deliver precisely controlled mechanical signals to live cells. An understanding of interactions and adaptation in response to forces at the interface between the surface of the cell and its immediate local environment may be key for de novo engineering of functional tissues from stem cell templates as well as for unraveling the mechanisms underlying multiscale development, growth and adaptation of organisms.

  17. Scaling behaviour of relaxation dependencies in metaloxide superconductors

    Science.gov (United States)

    Sidorenko, A. S.; Panaitov, G. I.; Gabovich, A. M.; Moiseev, D. P.; Postnikov, V. M.

    1990-01-01

    Superconducting glass state has been investigated in different types of metaloxide ceramics, Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O, Ba-Pb-Bi-O, using the highly sensitive SQUID magnetometer. The analysis of long-time relaxation processes of thermoremanent magnetization m(sup trm) (+) = M(sub o) - Slnt displayed scaling dependence of the decay rate S = -dM/dlnt on quantity of trapped magnetic flux M(sub o): 1gs = 31g M(sub o) - observed universal dependence S is approximately M(sup 3) (sub o) seems to one of the features of superconducting glass state in metaloxide ceramics.

  18. Continuum and crystal strain gradient plasticity with energetic and dissipative length scales

    Science.gov (United States)

    Faghihi, Danial

    This work, standing as an attempt to understand and mathematically model the small scale materials thermal and mechanical responses by the aid of Materials Science fundamentals, Continuum Solid Mechanics, Misro-scale experimental observations, and Numerical methods. Since conventional continuum plasticity and heat transfer theories, based on the local thermodynamic equilibrium, do not account for the microstructural characteristics of materials, they cannot be used to adequately address the observed mechanical and thermal response of the micro-scale metallic structures. Some of these cases, which are considered in this dissertation, include the dependency of thin films strength on the width of the sample and diffusive-ballistic response of temperature in the course of heat transfer. A thermodynamic-based higher order gradient framework is developed in order to characterize the mechanical and thermal behavior of metals in small volume and on the fast transient time. The concept of the thermal activation energy, the dislocations interaction mechanisms, nonlocal energy exchange between energy carriers and phonon-electrons interactions are taken into consideration in proposing the thermodynamic potentials such as Helmholtz free energy and rate of dissipation. The same approach is also adopted to incorporate the effect of the material microstructural interface between two materials (e.g. grain boundary in crystals) into the formulation. The developed grain boundary flow rule accounts for the energy storage at the grain boundary due to the dislocation pile up as well as energy dissipation caused by the dislocation transfer through the grain boundary. Some of the abovementioned responses of small scale metallic compounds are addressed by means of the numerical implementation of the developed framework within the finite element context. In this regard, both displacement and plastic strain fields are independently discretized and the numerical implementation is performed in

  19. DNA Duplex Length and Salt Concentration Dependence of Enthalpy−Entropy Compensation Parameters for DNA Melting

    KAUST Repository

    Starikov, E. B.

    2009-08-20

    Systematical differential calorimetry experiments on DNA oligomers with different lengths and placed in water solutions with various added salt concentrations may, in principle, unravel important information about the structure and dynamics of the DNA and their water-counterion surrounding. With this in mind, to reinterpret the most recent results of calorimetric experiments on DNA oligomers of such a kind, the recent enthalpy-entropy compensation theory has been used. It is demonstrated that the application of the latter could enable direct estimation of thermodynamic parameters of the microphase transitions connected to the changes in DNA dynamical regimes versus the length of the biopolymers and the ionic strengths of their water solutions, and this calls for much more systematical experimental and theoretical studies in this field. © 2009 American Chemical Society.

  20. Chain length and temperature dependence of alkanedithiol molecular conductance under ultra high vacuum.

    Science.gov (United States)

    Pires, Ellis; Macdonald, J Emyr; Elliott, Martin

    2013-10-07

    We report scanning tunnelling microscope (STM) measurements of the single molecule conductance of α,ω-alkanedithiols for a large range of molecular chain lengths (N = 3-10) and temperatures (180-390 K) under ultra high vacuum. Two STM-based measurement techniques were employed on molecules trapped between tip and substrate: (i) the well established current-distance or I(z) technique and (ii) a new I(V,z) technique in which the current-voltage characteristics are determined as the tip-substrate distance z is varied. Low, medium, and high conductance groups were observed for each molecular length, which were temperature independent over the range examined, consistent with off-resonance tunnelling. For N > 4 the current-voltage characteristics and conductance trend with chain length is well described using a simple rectangular tunnel barrier model with parameters in excellent agreement with previously reported values. However, both 1,3-propanedithiol (N = 3) and 1,4-butanedithiol (N = 4) show an anomalous behaviour which is qualitatively similar to, but much less pronounced than, that reported by Haiss et al. (Phys. Chem. Chem. Phys., 2009, 11, 10831) for measurements performed under air and nitrogen gas.

  1. Elastic energy storage and radial forces in the myofilament lattice depend on sarcomere length.

    Directory of Open Access Journals (Sweden)

    C David Williams

    Full Text Available We most often consider muscle as a motor generating force in the direction of shortening, but less often consider its roles as a spring or a brake. Here we develop a fully three-dimensional spatially explicit model of muscle to isolate the locations of forces and energies that are difficult to separate experimentally. We show the strain energy in the thick and thin filaments is less than one third the strain energy in attached cross-bridges. This result suggests the cross-bridges act as springs, storing energy within muscle in addition to generating the force which powers muscle. Comparing model estimates of energy consumed to elastic energy stored, we show that the ratio of these two properties changes with sarcomere length. The model predicts storage of a greater fraction of energy at short sarcomere lengths, suggesting a mechanism by which muscle function shifts as force production declines, from motor to spring. Additionally, we investigate the force that muscle produces in the radial or transverse direction, orthogonal to the direction of shortening. We confirm prior experimental estimates that place radial forces on the same order of magnitude as axial forces, although we find that radial forces and axial forces vary differently with changes in sarcomere length.

  2. Behavioral responses of wolves to roads: scale-dependent ambivalence

    Science.gov (United States)

    Nelson, Lindsey; Wabakken, Petter; Sand, Håkan; Liberg, Olof

    2014-01-01

    Throughout their recent recovery in several industrialized countries, large carnivores have had to cope with a changed landscape dominated by human infrastructure. Population growth depends on the ability of individuals to adapt to these changes by making use of new habitat features and at the same time to avoid increased risks of mortality associated with human infrastructure. We analyzed the summer movements of 19 GPS-collared resident wolves (Canis lupus L.) from 14 territories in Scandinavia in relation to roads. We used resource and step selection functions, including >12000 field-checked GPS-positions and 315 kill sites. Wolves displayed ambivalent responses to roads depending on the spatial scale, road type, time of day, behavioral state, and reproductive status. At the site scale (approximately 0.1 km2), they selected for roads when traveling, nearly doubling their travel speed. Breeding wolves moved the fastest. At the patch scale (10 km2), house density rather than road density was a significant negative predictor of wolf patch selection. At the home range scale (approximately 1000 km2), breeding wolves increased gravel road use with increasing road availability, although at a lower rate than expected. Wolves have adapted to use roads for ease of travel, but at the same time developed a cryptic behavior to avoid human encounters. This behavioral plasticity may have been important in allowing the successful recovery of wolf populations in industrialized countries. However, we emphasize the role of roads as a potential cause of increased human-caused mortality. PMID:25419085

  3. Distribution of dislocation source length and the size dependent yield strength in freestanding thin films

    NARCIS (Netherlands)

    Shishvan, Siamak Soleymani; Van der Giessen, Erik

    A method is proposed to estimate the size-dependent yield strength of columnar-grained freestanding thin films. The estimate relies on assuming a distribution of the size of Frank-Read sources, which is then translated into a log-normal distribution of the source strength, depending on film

  4. Length-Displacement Scaling of Lunar Thrust Faults and the Formation of Uphill-Facing Scarps

    Science.gov (United States)

    Hiesinger, Harald; Roggon, Lars; Hetzel, Ralf; Clark, Jaclyn D.; Hampel, Andrea; van der Bogert, Carolyn H.

    2017-04-01

    Lobate scarps are straight to curvilinear positive-relief landforms that occur on all terrestrial bodies [e.g., 1-3]. They are the surface manifestation of thrust faults that cut through and offset the upper part of the crust. Fault scarps on planetary surfaces provide the opportunity to study the growth of faults under a wide range of environmental conditions (e.g., gravity, temperature, pore pressure) [4]. We studied four lunar thrust-fault scarps (Simpelius-1, Morozov (S1), Fowler, Racah X-1) ranging in length from 1.3 km to 15.4 km [5] and found that their maximum total displacements are linearly correlated with length over one order of magnitude. We propose that during the progressive accumulation of slip, lunar faults propagate laterally and increase in length. On the basis of our measurements, the ratio of maximum displacement, D, to fault length, L, ranges from 0.017 to 0.028 with a mean value of 0.023 (or 2.3%). This is an order of magnitude higher than the value of 0.1% derived by theoretical considerations [4], and about twice as large as the value of 0.012-0.013 estimated by [6,7]. Our results, in addition to recently published findings for other lunar scarps [2,8], indicate that the D/L ratios of lunar thrust faults are similar to those of faults on Mercury and Mars (e.g., 1, 9-11], and almost as high as the average D/L ratio of 3% for faults on Earth [16,23]. Three of the investigated thrust fault scarps (Simpelius-1, Morozov (S1), Fowler) are uphill-facing scarps generated by slip on faults that dip in the same direction as the local topography. Thrust faults with such a geometry are common ( 60% of 97 studied scarps) on the Moon [e.g., 2,5,7]. To test our hypothesis that the surface topography plays an important role in the formation of uphill-facing fault scarps by controlling the vertical load on a fault plane, we simulated thrust faulting and its relation to topography with two-dimensional finite-element models using the commercial code ABAQUS

  5. Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

    Science.gov (United States)

    Fiscaletti, D.; Elsinga, G. E.; Attili, A.; Bisetti, F.; Buxton, O. R. H.

    2016-10-01

    The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor ei, with the vorticity vector ω , is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors | ei.ω ̂| are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e1, in contrast to the global tendency for ω to be aligned in parallel with the intermediate strain-rate eigenvector [Hamlington et al., Phys. Fluids 20, 111703 (2008), 10.1063/1.3021055]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment between ω and nonlocal e1 and that the strongly swirling worms are kinematically significant to this process.

  6. Manufacturing test of large scale hollow capsule and long length cladding in the large scale oxide dispersion strengthened (ODS) martensitic steel

    International Nuclear Information System (INIS)

    Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Fujiwara, Masayuki

    2004-04-01

    Mass production capability of oxide dispersion strengthened (ODS) martensitic steel cladding (9Cr) has being evaluated in the Phase II of the Feasibility Studies on Commercialized Fast Reactor Cycle System. The cost for manufacturing mother tube (raw materials powder production, mechanical alloying (MA) by ball mill, canning, hot extrusion, and machining) is a dominant factor in the total cost for manufacturing ODS ferritic steel cladding. In this study, the large-sale 9Cr-ODS martensitic steel mother tube which is made with a large-scale hollow capsule, and long length claddings were manufactured, and the applicability of these processes was evaluated. Following results were obtained in this study. (1) Manufacturing the large scale mother tube in the dimension of 32 mm OD, 21 mm ID, and 2 m length has been successfully carried out using large scale hollow capsule. This mother tube has a high degree of accuracy in size. (2) The chemical composition and the micro structure of the manufactured mother tube are similar to the existing mother tube manufactured by a small scale can. And the remarkable difference between the bottom and top sides in the manufactured mother tube has not been observed. (3) The long length cladding has been successfully manufactured from the large scale mother tube which was made using a large scale hollow capsule. (4) For reducing the manufacturing cost of the ODS steel claddings, manufacturing process of the mother tubes using a large scale hollow capsules is promising. (author)

  7. Taylor-plasticity-based analysis of length scale effects in void growth

    KAUST Repository

    Liu, Junxian

    2014-09-25

    We have studied the void growth problem by employing the Taylor-based strain gradient plasticity theories, from which we have chosen the following three, namely, the mechanism-based strain gradient (MSG) plasticity (Gao et al 1999 J. Mech. Phys. Solids 47 1239, Huang et al 2000 J. Mech. Phys. Solids 48 99-128), the Taylor-based nonlocal theory (TNT; 2001 Gao and Huang 2001 Int. J. Solids Struct. 38 2615) and the conventional theory of MSG (CMSG; Huang et al 2004 Int. J. Plast. 20 753). We have addressed the following three issues which occur when plastic deformation at the void surface is unconstrained. (1) Effects of elastic deformation. Elasticity is essential for cavitation instability. It is therefore important to guarantee that the gradient term entering the Taylor model is the effective plastic strain gradient instead of the total strain gradient. We propose a simple elastic-plastic decomposition method. When the void size approaches the minimum allowable initial void size related to the maximum allowable geometrically necessary dislocation density, overestimation of the flow stress due to the negligence of the elastic strain gradient is on the order of lεY/R0 near the void surface, where l, εY and R0 are, respectively, the intrinsic material length scale, the yield strain and the initial void radius. (2) MSG intrinsic inconsistency, which was initially mentioned in Gao et al (1999 J. Mech. Phys. Solids 47 1239) but has not been the topic of follow-up studies. We realize that MSG higher-order stress arises due to the linear-strain-field approximation within the mesoscale cell with a nonzero size, lε. Simple analysis shows that within an MSG mesoscale cell near the void surface, the difference between microscale and mesoscale strains is on the order of (lε/R0)2, indicating that when lε/R0 ∼ 1.0, the higher-order stress effect can make the MSG result considerably different from the TNT or CMSG results. (3) Critical condition for cavitation instability

  8. Hierarchical Self-Assembly of Peptide Amphiphiles: Form and Function at Multiple Length Scales

    Science.gov (United States)

    Zha, Runye Helen

    Hierarchical self-assembly, the organization of molecules into supramolecular structures of increasing size and complexity, is a potent tool for materials synthesis and requires understanding the connections of structure across multiple length scales. Herein, self-assembly of peptide amphiphiles (PAs) into nanoscopic and macroscopic materials is explored, and their anti-cancer applications are investigated. First, nanoscale assembly is examined in the context of an anti-angiogenic PA bearing the G-helix motif of maspin, a tumor suppressor protein. Assembly of this maspin-mimetic PA (MMPA) stabilizes the native G-helix conformation and improves binding to endothelial cells. Furthermore, PA nanostructures significantly increase cell adhesion to fibronectin as compared to G-helix peptide alone. Combined with its inhibitory effect on cell migration, MMPA nanostructures thus show anti-angiogenic activity on par with maspin protein in vitro and in vivo. Second, assembly of cationic PAs with hyaluronic acid (HA), an anionic polyelectrolyte, into macroscopic membranes is explored using PAs with identical formal charge but systematically varied self-assembly domains. Results suggest that membrane formation is dictated by the initial moments of component aggregation and is highly sensitive to PA molecular structure via nanoscale assembly. Specifically, PAs with beta-sheet forming residues are nanofibrous and have high surface charge density, leading to robust membranes with aligned-fiber microstructure. PAs without beta-sheet forming residues are nanospherical and have low surface charge density, leading to weak membranes with non-fibrous finger-like microstructure. Lastly, the principles of PA-HA membrane assembly are applied towards development of anti-cancer therapeutic biomaterials. Here, cytotoxic PAs bearing the epitope (KLAKLAKbeta)2 are co-assembled with non-bioactive cationic PA in order to achieve varying nanoscale morphology. These nanostructures are then

  9. Improvement in muscle strength with low-load isotonic training depends on fascicle length but not joint angle.

    Science.gov (United States)

    Tanaka, Hiroki; Ikezoe, Tome; Nakamura, Masatoshi; Yanase, Ko; Fujita, Kosuke; Motomura, Yoshiki; Kusano, Ken; Araki, Kojiro; Umehara, Jun; Saeki, Junya; Morishita, Katsuyuki; Ichihashi, Noriaki

    2018-01-01

    In this study we investigate whether low-load isotonic training will elicit greater improvement in muscle strength at the same fascicle length, rather than at the same joint angle. Sixteen healthy men (24.1 ± 2.5 years of age) were randomly divided into intervention and control groups. Pre- and posttraining maximum isometric and isokinetic strengths and fascicle lengths of the medial gastrocnemius muscle were measured. Isotonic resistance training at 15 ° to 30 ° ankle plantarflexion at low intensity was conducted for 4 weeks. The maximum isometric and isokinetic strength of the intervention group increased significantly only at 15 ° dorsiflexion and 8 ° to 12 ° dorsiflexion. Fascicle length during maximum voluntary contraction at 15 ° dorsiflexion to 0 ° was similar to fascicle length under training conditions. It is possible that the improvement in muscle strength with low-load training depends on fascicle length rather than joint angle. Muscle Nerve 57: 83-89, 2018. © 2017 Wiley Periodicals, Inc.

  10. Dependence of beach seine net efficiency on net length and diel period

    Czech Academy of Sciences Publication Activity Database

    Říha, Milan; Kubečka, Jan; Mrkvička, Tomáš; Prchalová, Marie; Čech, Martin; Draštík, Vladislav; Frouzová, Jaroslava; Hladík, M.; Hohausová, Eva; Jarolím, Oldřich; Jůza, Tomáš; Kratochvíl, Michal; Peterka, Jiří; Tušer, Michal; Vašek, Mojmír

    2008-01-01

    Roč. 21, č. 4 (2008), s. 411-418 ISSN 0990-7440 R&D Projects: GA ČR(CZ) GA206/06/1371; GA ČR(CZ) GA206/07/1392; GA AV ČR(CZ) 1QS600170504 Grant - others:EU(XE) GOCE-CT-2003-505298 Institutional research plan: CEZ:AV0Z60170517 Keywords : beach seine net * net length * efficiency estimate * size selectivity * freshwater fish * European reservoir Subject RIV: GL - Fishing Impact factor: 0.667, year: 2008

  11. Characterizing the reinforcement mechanisms in multiwall nanotube/polycarbonate composites across different length and time scales

    Science.gov (United States)

    Duncan, Renee Kelly

    The enthusiasm and interest in the potential properties of nanotube (NT)/polymer composites are based on several factors, including the potential for unsurpassed enhancements in mechanical properties together with electrical, thermal and optical properties. Using multiwall nanotubes (MWNTs) grown to a long aspect ratio, the study found that fragmentation tests can be completed in a similar manner to traditional fiber composites. It was found that the fragmentation length does not depend on the angle of the nanotube to the loading direction hence the ISS does not change with the orientation angle of the nanotube in the composite. A critical aspect ratio of 100 and 300 for untreated nanotubes (ARNT) and treated nanotubes (EPNT), respectively was also measured. For nanotubes that are well dispersed in the polycarbonate, it was observed at a critical angle of 60° that there was a change in failure mechanism from pullout to fracture of the nanotubes due to bending shear. Because the tensile strength of a MWNT is unknown a cumulative distribution was used to characterize the relative interfacial shear strength as a function of nanotube chemical modification. The second goal of this thesis is to use Dynamic Mechanical Thermal Analysis (DMTA) with controlled aspect ratios of multiwall nanotubes (MWNT) to isolate and quantify the effects of the interfacial region on modulus enhancements in nanotube-reinforced composites. One major finding of this study was that the shortest aspect ratio showed a significantly broadened relaxation spectrum than the longer aspect ratio nanotubes, despite the longer aspect ratio nanotubes being more percolated at the given weight percent. There is also a direct correlation between the free space parameter of the short aspect ratio nantoubes network and broadening of the relaxation spectrum, concluded to be a result of increased interaction of the interfacial polymer. The study found agreement with the premise that at a constant filler weight

  12. Comment on ``Length-dependent translation of messenger RNA by ribosomes''

    Science.gov (United States)

    Zhang, Yunxin

    2012-02-01

    In a recent paper by Valleriani [Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.83.042903 83, 042903 (2011)], a simple model for the translation of messenger RNA (mRNA) is presented. Using this model, the protein translational ratio r, defined as the ratio of protein translation rate ωtl from mRNA to protein degradation rate ωp, is obtained. The key point in obtaining the translational ratio r is to get the protein translation rate ωtl. In Valleriani 's paper, ωtl is obtained as the mean value of the measured translation rate, which is the ratio of the synthesized protein number to the mRNA lifetime. However, in experiments, different methods might be used to obtain the value of ωtl. Therefore, to apply Valleriani 's model to more general experiments, in this Comment three methods to obtain the translation rate ωtl, and consequently the translational ratio r, are presented. Based on one of the methods which might be employed in most of the experiments, we find that the translational ratio r decays exponentially with mRNA length in prokaryotic cells, and decays reciprocally with mRNA length in eukaryotic cells. This result is slight different from that which was obtained in Valleriani 's paper.

  13. Vortex-pair nucleation at defects: A mechanism for anomalous temperature dependence in the superconducting screening length

    International Nuclear Information System (INIS)

    Hebard, A.F.; Fiory, A.T.; Siegal, M.P.; Phillips, J.M.; Haddon, R.C.

    1991-01-01

    Low-field ac screening measurements on YBa 2 Cu 3 O 7-δ films and (BEDT-TTF) 2 Cu(SCN) 2 crystals [where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene], both thought to contain a high density of defects, reveal a diminution of screening and a common extrinsic temperature dependence of the screening length λ. Vortex-core pinning at the defects is shown to give a low-temperature T 2 power-law temperature dependence to λ that, in contrast to the exponential behavior expected from s-wave pairing, can be mistaken as evidence for lines or nodes of the energy gap on the Fermi surface

  14. A micromechanical approach of suffusion based on a length scale analysis of the grain detachment and grain transport processes.

    Science.gov (United States)

    Wautier, Antoine; Bonelli, Stéphane; Nicot, François

    2017-06-01

    Suffusion is the selective erosion of the finest particles of a soil subjected to an internal flow. Among the four types of internal erosion and piping identified today, suffusion is the least understood. Indeed, there is a lack of micromechanical approaches for identifying the critical microstructural parameters responsible for this process. Based on a discrete element modeling of non cohesive granular assemblies, specific micromechanical tools are developed in a unified framework to account for the two first steps of suffusion, namely the grain detachment and the grain transport processes. Thanks to the use of an enhanced force chain definition and autocorrelation functions the typical lengths scales associated with grain detachment are characterized. From the definition of transport paths based on a graph description of the pore space the typical lengths scales associated with grain transport are recovered. For a uniform grain size distribution, a separation of scales between these two processes exists for the finest particles of a soil

  15. Sub-pixel correlation length neutron imaging: Spatially resolved scattering information of microstructures on a macroscopic scale

    Science.gov (United States)

    Harti, Ralph P.; Strobl, Markus; Betz, Benedikt; Jefimovs, Konstantins; Kagias, Matias; Grünzweig, Christian

    2017-01-01

    Neutron imaging and scattering give data of significantly different nature and traditional methods leave a gap of accessible structure sizes at around 10 micrometers. Only in recent years overlap in the probed size ranges could be achieved by independent application of high resolution scattering and imaging methods, however without providing full structural information when microstructures vary on a macroscopic scale. In this study we show how quantitative neutron dark-field imaging with a novel experimental approach provides both sub-pixel resolution with respect to microscopic correlation lengths and imaging of macroscopic variations of the microstructure. Thus it provides combined information on multiple length scales. A dispersion of micrometer sized polystyrene colloids was chosen as a model system to study gravity induced crystallisation of microspheres on a macro scale, including the identification of ordered as well as unordered phases. Our results pave the way to study heterogeneous systems locally in a previously impossible manner. PMID:28303923

  16. A micromechanical approach of suffusion based on a length scale analysis of the grain detachment and grain transport processes.

    Directory of Open Access Journals (Sweden)

    Wautier Antoine

    2017-01-01

    Full Text Available Suffusion is the selective erosion of the finest particles of a soil subjected to an internal flow. Among the four types of internal erosion and piping identified today, suffusion is the least understood. Indeed, there is a lack of micromechanical approaches for identifying the critical microstructural parameters responsible for this process. Based on a discrete element modeling of non cohesive granular assemblies, specific micromechanical tools are developed in a unified framework to account for the two first steps of suffusion, namely the grain detachment and the grain transport processes. Thanks to the use of an enhanced force chain definition and autocorrelation functions the typical lengths scales associated with grain detachment are characterized. From the definition of transport paths based on a graph description of the pore space the typical lengths scales associated with grain transport are recovered. For a uniform grain size distribution, a separation of scales between these two processes exists for the finest particles of a soil

  17. Economies of scale in British intensive care units and combined intensive care/high dependency units.

    Science.gov (United States)

    Jacobs, Philip; Rapoport, John; Edbrooke, David

    2004-04-01

    To estimate the relationship between size of intensive care unit and combined intensive care/high dependency units and average costs per patient day. Retrospective data analysis. Multiple regression of average costs on critical care unit size, controlling for teaching status, type of unit, occupancy rate and average length of stay. Seventy-two United Kingdom adult intensive care and combined intensive care/high dependency units submitting expenditure data for the financial year 2000-2001 as part of the Critical Care National Cost Block Programme. None. The main outcome measures were total cost per patient day and the following components: staffing cost, consumables cost and clinical support services costs. Nursing Whole Time Equivalents per patient day were recorded. The unit size variable has a negative and statistically significant ( peconomies of scale in planning intensive care and combined intensive care/high dependency units.

  18. Dependence of micelle size and shape on detergent alkyl chain length and head group.

    Science.gov (United States)

    Oliver, Ryan C; Lipfert, Jan; Fox, Daniel A; Lo, Ryan H; Doniach, Sebastian; Columbus, Linda

    2013-01-01

    Micelle-forming detergents provide an amphipathic environment that can mimic lipid bilayers and are important tools for solubilizing membrane proteins for functional and structural investigations in vitro. However, the formation of a soluble protein-detergent complex (PDC) currently relies on empirical screening of detergents, and a stable and functional PDC is often not obtained. To provide a foundation for systematic comparisons between the properties of the detergent micelle and the resulting PDC, a comprehensive set of detergents commonly used for membrane protein studies are systematically investigated. Using small-angle X-ray scattering (SAXS), micelle shapes and sizes are determined for phosphocholines with 10, 12, and 14 alkyl carbons, glucosides with 8, 9, and 10 alkyl carbons, maltosides with 8, 10, and 12 alkyl carbons, and lysophosphatidyl glycerols with 14 and 16 alkyl carbons. The SAXS profiles are well described by two-component ellipsoid models, with an electron rich outer shell corresponding to the detergent head groups and a less electron dense hydrophobic core composed of the alkyl chains. The minor axis of the elliptical micelle core from these models is constrained by the length of the alkyl chain, and increases by 1.2-1.5 Å per carbon addition to the alkyl chain. The major elliptical axis also increases with chain length; however, the ellipticity remains approximately constant for each detergent series. In addition, the aggregation number of these detergents increases by ∼16 monomers per micelle for each alkyl carbon added. The data provide a comprehensive view of the determinants of micelle shape and size and provide a baseline for correlating micelle properties with protein-detergent interactions.

  19. Dependence of micelle size and shape on detergent alkyl chain length and head group.

    Directory of Open Access Journals (Sweden)

    Ryan C Oliver

    Full Text Available Micelle-forming detergents provide an amphipathic environment that can mimic lipid bilayers and are important tools for solubilizing membrane proteins for functional and structural investigations in vitro. However, the formation of a soluble protein-detergent complex (PDC currently relies on empirical screening of detergents, and a stable and functional PDC is often not obtained. To provide a foundation for systematic comparisons between the properties of the detergent micelle and the resulting PDC, a comprehensive set of detergents commonly used for membrane protein studies are systematically investigated. Using small-angle X-ray scattering (SAXS, micelle shapes and sizes are determined for phosphocholines with 10, 12, and 14 alkyl carbons, glucosides with 8, 9, and 10 alkyl carbons, maltosides with 8, 10, and 12 alkyl carbons, and lysophosphatidyl glycerols with 14 and 16 alkyl carbons. The SAXS profiles are well described by two-component ellipsoid models, with an electron rich outer shell corresponding to the detergent head groups and a less electron dense hydrophobic core composed of the alkyl chains. The minor axis of the elliptical micelle core from these models is constrained by the length of the alkyl chain, and increases by 1.2-1.5 Å per carbon addition to the alkyl chain. The major elliptical axis also increases with chain length; however, the ellipticity remains approximately constant for each detergent series. In addition, the aggregation number of these detergents increases by ∼16 monomers per micelle for each alkyl carbon added. The data provide a comprehensive view of the determinants of micelle shape and size and provide a baseline for correlating micelle properties with protein-detergent interactions.

  20. The role of the CI expansion length in time-dependent studies

    Science.gov (United States)

    Ulusoy, Inga S.; Stewart, Zachary; Wilson, Angela K.

    2018-01-01

    With the recent advances in experimental attosecond science, theoretical predictions of electron dynamics can now be validated against experiment. Time-dependent studies of the electron motion in molecules can be used to obtain information about electronic transitions and the interaction of the electrons with electromagnetic fields. Often, these approaches rely on single-excited wave functions. Presented here is a first attempt to evaluate the accuracy of the time-dependent configuration interaction method so that the optimal representation of the electronic wave function for time-dependent studies can be assessed. A quantifier is determined that can aid in finding this optimal representation. The approach is demonstrated on a variety of molecules that include both localized and intramolecular charge transfer electron excitations. Observables including excitation energies, dipole moments, strengths, and static polarizabilities are obtained from time-independent and time-dependent calculations and are compared to experimental data. In this way, a rigorous routine is developed by which the reliability and accuracy of the CI wave function can be assessed and which represents a first step to a more quantitative description of electron dynamics in molecules.

  1. Path length dependence of jet quenching measured with ALICE at the LHC

    NARCIS (Netherlands)

    Bertens, R.A.

    2016-01-01

    Jets are used to probe the quark-gluon plasma (QGP) that is created in heavy-ion collisions, by using the fact that medium-induced parton energy loss from elastic and radiative interactions between partons and the QGP lead to a modification of the measured jet spectrum. The dependence of the energy

  2. Exploring the Severity of Dependence Scale (SDS) as a possible measure of nicotine dependence.

    Science.gov (United States)

    Mercincavage, Melissa; Smyth, Joshua M; Branstetter, Steven A; Catley, Delwyn

    2016-01-01

    The time to first cigarette (TTFC) of the day is an emerging single-item indicator of nicotine dependence due to its robust associations with indices of physical dependence. However, it is unclear if this measure adequately captures other dimensions of dependence. The Severity of Dependence Scale (SDS) is a brief questionnaire used to assess psychological aspects of dependence that has not yet been extensively applied to smoking research. We examined associations between the SDS and TTFC among 255 smokers during the baseline session of a cessation trial. We also examined associations of the SDS and TTFC with biobehavioral dependence indices, quitting behaviors, and cognitive-affective variables and compared the relative contributions of both measures in predicting these variables. TTFC was unrelated to SDS total score, but was related to individual SDS items. TTFC, but not SDS, was correlated with indices of physical dependence (e.g., cigarettes per day [CPD], carbon monoxide [CO]). Both TTFC and SDS were associated with quitting behaviors, with opposite directionality of associations. TTFC and SDS were both associated with cognitive-affective variables, but SDS outperformed TTFC in strength and number of these relationships. Including both the SDS and TTFC as regression model predictors often increased the amount of variance explained. Findings suggest that SDS and TTFC assess different constructs of nicotine dependence; among smokers, the SDS appears to tap into nonphysical components of dependence (e.g., loss of control) that relate to quitting motivation and affect. Assessing nicotine dependence using only the SDS may fail to capture physical dependence and, further, may not reflect the same domains of addiction the SDS assesses in other drugs of abuse. Nonetheless, using 3 SDS items in addition to TTFC may offer utility over using TTFC alone.

  3. Measurement error causes scale-dependent threshold erosion of biological signals in animal movement data.

    Science.gov (United States)

    Bradshaw, Corey J A; Sims, David W; Hays, Graeme C

    2007-03-01

    Recent advances in telemetry technology have created a wealth of tracking data available for many animal species moving over spatial scales from tens of meters to tens of thousands of kilometers. Increasingly, such data sets are being used for quantitative movement analyses aimed at extracting fundamental biological signals such as optimal searching behavior and scale-dependent foraging decisions. We show here that the location error inherent in various tracking technologies reduces the ability to detect patterns of behavior within movements. Our analyses endeavored to set out a series of initial ground rules for ecologists to help ensure that sampling noise is not misinterpreted as a real biological signal. We simulated animal movement tracks using specialized random walks known as Lévy flights at three spatial scales of investigation: 100-km, 10-km, and 1-km maximum daily step lengths. The locations generated in the simulations were then blurred using known error distributions associated with commonly applied tracking methods: the Global Positioning System (GPS), Argos polar-orbiting satellites, and light-level geolocation. Deviations from the idealized Lévy flight pattern were assessed for each track after incrementing levels of location error were applied at each spatial scale, with additional assessments of the effect of error on scale-dependent movement patterns measured using fractal mean dimension and first-passage time (FPT) analyses. The accuracy of parameter estimation (Lévy mu, fractal mean D, and variance in FPT) declined precipitously at threshold errors relative to each spatial scale. At 100-km maximum daily step lengths, error standard deviations of > or = 10 km seriously eroded the biological patterns evident in the simulated tracks, with analogous thresholds at the 10-km and 1-km scales (error SD > or = 1.3 km and 0.07 km, respectively). Temporal subsampling of the simulated tracks maintained some elements of the biological signals depending on

  4. Scale-dependent bias from the reconstruction of non-Gaussian distributions

    International Nuclear Information System (INIS)

    Chongchitnan, Sirichai; Silk, Joseph

    2011-01-01

    Primordial non-Gaussianity introduces a scale-dependent variation in the clustering of density peaks corresponding to rare objects. This variation, parametrized by the bias, is investigated on scales where a linear perturbation theory is sufficiently accurate. The bias is obtained directly in real space by comparing the one- and two-point probability distributions of density fluctuations. We show that these distributions can be reconstructed using a bivariate Edgeworth series, presented here up to an arbitrarily high order. The Edgeworth formalism is shown to be well-suited for ''local'' cubic-order non-Gaussianity parametrized by g NL . We show that a strong scale dependence in the bias can be produced by g NL of order 10 5 , consistent with cosmic microwave background constraints. On a separation length of ∼100 Mpc, current constraints on g NL still allow the bias for the most massive clusters to be enhanced by 20-30% of the Gaussian value. We further examine the bias as a function of mass scale, and also explore the relationship between the clustering and the abundance of massive clusters in the presence of g NL . We explain why the Edgeworth formalism, though technically challenging, is a very powerful technique for constraining high-order non-Gaussianity with large-scale structures.

  5. Channel length scaling and the impact of metal gate work function ...

    Indian Academy of Sciences (India)

    port and experimental data extracted in DG-MOSFETs devices. At these channel length limits, the susceptibility of the transistor to short-channel effects (SCE) is monitored in several ways such as threshold voltage (VTH), subthreshold voltage slope (S), leakage current (IOFF) and the drain-induced barrier lowering (DIBL).

  6. Different cellular response mechanisms contribute to the length-dependent cytotoxicity of multi-walled carbon nanotubes

    Science.gov (United States)

    Liu, Dun; Wang, Lijun; Wang, Zhigang; Cuschieri, Alfred

    2012-07-01

    To date, there has not been an agreement on the best methods for the characterisation of multi-walled carbon nanotube (MWCNT) toxicity. The length of MWCNTs has been identified as a factor in in vitro and in vivo studies, in addition to their purity and biocompatible coating. Another unresolved issue relates to the variable toxicity of MWCNTs on different cell types. The present study addressed the effects of MWCNTs' length on mammalian immune and epithelial cancer cells RAW264.7 and MCF-7, respectively. Our data confirm that MWCNTs induce cytotoxicity in a length- and cell type-dependent manner. Whereas, longer (3 to 14 μm) MWCNTs exert high toxicity, especially to RAW264.7 cells, shorter (1.5 μm) MWCNTs are significantly less cytotoxic. These findings confirm that the degree of biocompatibility of MWCNTs is closely related to their length and that immune cells appear to be more susceptible to damage by MWCNTs. Our study also indicates that MWCNT nanotoxicity should be analysed for various components of cellular response, and cytotoxicity data should be validated by the use of more than one assay system. Results from chromogenic-based assays should be confirmed by trypan blue exclusion.

  7. Age-dependent associations between telomere length and environmental conditions in roe deer.

    Science.gov (United States)

    Wilbourn, Rachael V; Froy, Hannah; McManus, Marie-Christina; Cheynel, Louise; Gaillard, Jean-Michel; Gilot-Fromont, Emmanuelle; Regis, Corinne; Rey, Benjamin; Pellerin, Maryline; Lemaître, Jean-François; Nussey, Daniel H

    2017-09-01

    Telomere length (TL) represents a promising biomarker of overall physiological state and of past environmental experiences, which could help us understand the drivers of life-history variation in natural populations. A growing number of studies in birds suggest that environmental stress or poor environmental conditions are associated with shortened TL, but studies of such relationships in wild mammals are lacking. Here, we compare leucocyte TL from cross-sectional samples collected from two French populations of roe deer which experience different environmental conditions. We found that, as predicted, TL was shorter in the population experiencing poor environmental conditions but that this difference was only significant in older individuals and was independent of sex and body mass. Unexpectedly, the difference was underpinned by a significant increase in TL with age in the population experiencing good environmental conditions, while there was no detectable relationship with age in poor conditions. These results demonstrate both the environmental sensitivity and complexity of telomere dynamics in natural mammal populations, and highlight the importance of longitudinal data to disentangle the within- and among-individual processes that generate them. © 2017 The Authors.

  8. Chain length dependence of polyol synthesis of zinc ferrite nanoparticles: why is diethylene glycol so different?

    Science.gov (United States)

    Rishikeshi, Supriya N; Joshi, Satyawati S; Temgire, Mayur K; Bellare, Jayesh R

    2013-04-21

    Superparamagnetic ZnFe2O4 nanoparticles with size range of 28-38 nm were synthesized by polyol process based on use of varying chain length glycols as solvent. We have offered, for the first time, the plausible mechanism behind in situ formation of zinc ferric oxalate hydroxide hydrate [Fe2Zn(C2O4)2(OH)3](+)·4H2O complex from diethylene and polyethylene glycol. We are also reporting, the magnetic properties of above complexes. We have found a ferromagnetic ordering in precursor complex compounds. The intermediate hydrocarbon chain between the oxalato bridged metal cations plays a crucial role in obtaining anomalous magnetic behavior. ZnFe2O4 nanoparticles obtained after annealing the DEGylated precursor complex (precursor complex formed in diethylene glycol) showed the highest superparamagnetic (SPM) behavior (22.4 emu g(-1)) among others. The reasons for anomalous SPM behavior of ZnFe2O4 nanoparticles are explained on the basis of the degree of inversion of the spinel structure, high surface-to-volume ratio, which causes non-collinear spin arrangement in a surface layer and higher oxygen concentration on the surface of dead organic layer, which increases the unpaired valence electrons leading to uncompensated surface spins.

  9. A multi-resolution analysis of lidar-DTMs to identify geomorphic processes from characteristic topographic length scales

    Science.gov (United States)

    Sangireddy, H.; Passalacqua, P.; Stark, C. P.

    2013-12-01

    Characteristic length scales are often present in topography, and they reflect the driving geomorphic processes. The wide availability of high resolution lidar Digital Terrain Models (DTMs) allows us to measure such characteristic scales, but new methods of topographic analysis are needed in order to do so. Here, we explore how transitions in probability distributions (pdfs) of topographic variables such as (log(area/slope)), defined as topoindex by Beven and Kirkby[1979], can be measured by Multi-Resolution Analysis (MRA) of lidar DTMs [Stark and Stark, 2001; Sangireddy et al.,2012] and used to infer dominant geomorphic processes such as non-linear diffusion and critical shear. We show this correlation between dominant geomorphic processes to characteristic length scales by comparing results from a landscape evolution model to natural landscapes. The landscape evolution model MARSSIM Howard[1994] includes components for modeling rock weathering, mass wasting by non-linear creep, detachment-limited channel erosion, and bedload sediment transport. We use MARSSIM to simulate steady state landscapes for a range of hillslope diffusivity and critical shear stresses. Using the MRA approach, we estimate modal values and inter-quartile ranges of slope, curvature, and topoindex as a function of resolution. We also construct pdfs at each resolution and identify and extract characteristic scale breaks. Following the approach of Tucker et al.,[2001], we measure the average length to channel from ridges, within the GeoNet framework developed by Passalacqua et al.,[2010] and compute pdfs for hillslope lengths at each scale defined in the MRA. We compare the hillslope diffusivity used in MARSSIM against inter-quartile ranges of topoindex and hillslope length scales, and observe power law relationships between the compared variables for simulated landscapes at steady state. We plot similar measures for natural landscapes and are able to qualitatively infer the dominant geomorphic

  10. Dependency on scale of power numbers of Rushton disc turbines

    Energy Technology Data Exchange (ETDEWEB)

    Bujalski, W.; Nienow, A.W.; Chatwin, S.; Cooke, M.

    1987-01-01

    Extensive and very accurate power numbers have been obtained for a wide range of Rushton disc turbines using water as the working fluid in six fully baffled vessels from 0.22 to 1.83 m diameter. The results show that for Reynolds numbers greater than or equal to 2 x 10/sup 4/, the average peak power number anti Po is dependent on the disc thickness (x/sub 1/) to impeller diameter (D) ratio and to the vessel diameter (T). Provided x/sub 1//D is constant, anti Po is independent of impeller to vessel ratio in the range 0.25 less than or equal to D/T less than or equal to 0.70. For 0.01 less than or equal to x/sub 1//D less than or equal to 0.05 and for the range of vessels studied, the equation anti Po = 2.5(x/sub 1//D)/sup -0.2/ (T/T/sub 0/)/sup 0.065/ fitted the data to within +/- 3% where T/sub 0/ is a 1 m diameter vessel. An F-test shows that the inclusion of the small effect of scale, (T/T/sub 0/), is statistically significant at the 99% level. The implications of these scale and geometrical effects for mixing research, process design and scale-up are discussed.

  11. ION-SCALE TURBULENCE IN THE INNER HELIOSPHERE: RADIAL DEPENDENCE

    Energy Technology Data Exchange (ETDEWEB)

    Comisel, H.; Motschmann, U.; Büchner, J.; Narita, Y.; Nariyuki, Y. [University of Toyama, Faculty of Human Development, 3190, Gofuku, Toyama, 930-8555 (Japan)

    2015-10-20

    The evolution of the ion-scale plasma turbulence in the inner heliosphere is studied by associating the plasma parameters for hybrid-code turbulence simulations to the radial distance from the Sun via a Solar wind model based mapping procedure. Using a mapping based on a one-dimensional solar wind expansion model, the resulting ion-kinetic scale turbulence is related to the solar wind distance from the Sun. For this purpose the mapping is carried out for various values of ion beta that correspond to the heliocentric distance. It is shown that the relevant normal modes such as ion cyclotron and ion Bernstein modes will occur first at radial distances of about 0.2–0.3 AU, i.e., near the Mercury orbit. This finding can be used as a reference, a prediction to guide the in situ measurements to be performed by the upcoming Solar Orbiter and Solar Probe Plus missions. Furthermore, a radial dependence of the wave-vector anisotropy was obtained. For astrophysical objects this means that the spatial scales of filamentary structures in interstellar media or astrophysical jets can be predicted for photometric observations.

  12. Interaction and dynamics of (alkylamide + electrolyte) deep eutectics: Dependence on alkyl chain-length, temperature, and anion identity

    International Nuclear Information System (INIS)

    Guchhait, Biswajit; Das, Suman; Daschakraborty, Snehasis; Biswas, Ranjit

    2014-01-01

    Here we investigate the solute-medium interaction and solute-centered dynamics in (RCONH 2 + LiX) deep eutectics (DEs) via carrying out time-resolved fluorescence measurements and all-atom molecular dynamics simulations at various temperatures. Alkylamides (RCONH 2 ) considered are acetamide (CH 3 CONH 2 ), propionamide (CH 3 CH 2 CONH 2 ), and butyramide (CH 3 CH 2 CH 2 CONH 2 ); the electrolytes (LiX) are lithium perchlorate (LiClO 4 ), lithium bromide (LiBr), and lithium nitrate (LiNO 3 ). Differential scanning calorimetric measurements reveal glass transition temperatures (T g ) of these DEs are ∼195 K and show a very weak dependence on alkyl chain-length and electrolyte identity. Time-resolved and steady state fluorescence measurements with these DEs have been carried out at six-to-nine different temperatures that are ∼100–150 K above their individual T g s. Four different solute probes providing a good spread of fluorescence lifetimes have been employed in steady state measurements, revealing strong excitation wavelength dependence of probe fluorescence emission peak frequencies. Extent of this dependence, which shows sensitivity to anion identity, has been found to increase with increase of amide chain-length and decrease of probe lifetime. Time-resolved measurements reveal strong fractional power dependence of average rates for solute solvation and rotation with fraction power being relatively smaller (stronger viscosity decoupling) for DEs containing longer amide and larger (weaker decoupling) for DEs containing perchlorate anion. Representative all-atom molecular dynamics simulations of (CH 3 CONH 2 + LiX) DEs at different temperatures reveal strongly stretched exponential relaxation of wavevector dependent acetamide self dynamic structure factor with time constants dependent both on ion identity and temperature, providing justification for explaining the fluorescence results in terms of temporal heterogeneity and amide clustering in these multi

  13. Modelling of multiple short-length-scale stall cells in an axial compressor using evolved GMDH neural networks

    International Nuclear Information System (INIS)

    Amanifard, N.; Nariman-Zadeh, N.; Farahani, M.H.; Khalkhali, A.

    2008-01-01

    Over the past 15 years there have been several research efforts to capture the stall inception nature in axial flow compressors. However previous analytical models could not explain the formation of short-length-scale stall cells. This paper provides a new model based on evolved GMDH neural network for transient evolution of multiple short-length-scale stall cells in an axial compressor. Genetic Algorithms (GAs) are also employed for optimal design of connectivity configuration of such GMDH-type neural networks. In this way, low-pass filter (LPF) pressure trace near the rotor leading edge is modelled with respect to the variation of pressure coefficient, flow rate coefficient, and number of rotor rotations which are defined as inputs

  14. Dependence of the crossing time on the sequence length in the continuous-time mutation-selection model

    International Nuclear Information System (INIS)

    Gill, Wonpyong

    2010-01-01

    The dependence of the crossing time on the sequence length in the coupled and the decoupled continuous-time mutation-selection models in an asymmetric sharply-peaked landscape with a positive asymmetric parameter, r, was examined for a fixed extension parameter, E, which is defined as the average Hamming distance from the optimal allele of the initial quasispecies divided by the sequence length. Two versions of the coupled mutation-selection model, the continuous-time version and discrete-time version, were found to have the same boundary between the deterministic and the stochastic regions, which is different from the boundary between the deterministic and the stochastic regions in the decoupled continuous-time mutation-selection model. The maximum sequence length for a finite population that can evolve through the fitness barrier, e.g., within 10 6 generations in the decoupled continuous-time mutation-selection model, increased by approximately eight sequence elements with increasing population size by a factor of a thousand when E = 0.1 and r = 0.1. The crossing time for a finite population in the decoupled model in the stochastic region was shorter than the crossing time for a finite population in the coupled model, and the maximum evolvable sequence length for a finite population in the decoupled model was longer than the maximum evolvable sequence length for a finite population in the coupled model. This suggests that a mutation allowed at any time during the life cycle might be more effective than a mutation allowed only at reproduction events when a finite population transits to a higher fitness peak through the fitness barrier in an asymmetric sharply-peaked landscape.

  15. Distinct Length Scales in the VO2 Metal-Insulator Transition Revealed by Bi-chromatic Optical Probing

    International Nuclear Information System (INIS)

    Wang, Lei; Novikova, Irina B.; Klopf, John M.; Madaras, Scott E.; Williams, Gwyn P.; Madaras, Eric; Lu, Liwei; Wolf, Stuart A.; Lukaszew, Rosa A.

    2014-01-01

    Upon a heating-induced metal-insulator transition (MIT) in VO 2 , microscopic metallic VO 2 puddles nucleate and coarsen within the insulating matrix. This coexistence of the two phases across the transition spans distinct length scales as their relative domain sizes change. Far-field optical probing is applied to follow the dynamic evolution of the highly correlated metallic domains as the MIT progresses

  16. The scale dependence of optical diversity in a prairie ecosystem

    Science.gov (United States)

    Gamon, J. A.; Wang, R.; Stilwell, A.; Zygielbaum, A. I.; Cavender-Bares, J.; Townsend, P. A.

    2015-12-01

    Biodiversity loss, one of the most crucial challenges of our time, endangers ecosystem services that maintain human wellbeing. Traditional methods of measuring biodiversity require extensive and costly field sampling by biologists with extensive experience in species identification. Remote sensing can be used for such assessment based upon patterns of optical variation. This provides efficient and cost-effective means to determine ecosystem diversity at different scales and over large areas. Sampling scale has been described as a "fundamental conceptual problem" in ecology, and is an important practical consideration in both remote sensing and traditional biodiversity studies. On the one hand, with decreasing spatial and spectral resolution, the differences among different optical types may become weak or even disappear. Alternately, high spatial and/or spectral resolution may introduce redundant or contradictory information. For example, at high resolution, the variation within optical types (e.g., between leaves on a single plant canopy) may add complexity unrelated to specie richness. We studied the scale-dependence of optical diversity in a prairie ecosystem at Cedar Creek Ecosystem Science Reserve, Minnesota, USA using a variety of spectrometers from several platforms on the ground and in the air. Using the coefficient of variation (CV) of spectra as an indicator of optical diversity, we found that high richness plots generally have a higher coefficient of variation. High resolution imaging spectrometer data (1 mm pixels) showed the highest sensitivity to richness level. With decreasing spatial resolution, the difference in CV between richness levels decreased, but remained significant. These findings can be used to guide airborne studies of biodiversity and develop more effective large-scale biodiversity sampling methods.

  17. Correlation Lengths for Estimating the Large-Scale Carbon and Heat Content of the Southern Ocean

    Science.gov (United States)

    Mazloff, M. R.; Cornuelle, B. D.; Gille, S. T.; Verdy, A.

    2018-02-01

    The spatial correlation scales of oceanic dissolved inorganic carbon, heat content, and carbon and heat exchanges with the atmosphere are estimated from a realistic numerical simulation of the Southern Ocean. Biases in the model are assessed by comparing the simulated sea surface height and temperature scales to those derived from optimally interpolated satellite measurements. While these products do not resolve all ocean scales, they are representative of the climate scale variability we aim to estimate. Results show that constraining the carbon and heat inventory between 35°S and 70°S on time-scales longer than 90 days requires approximately 100 optimally spaced measurement platforms: approximately one platform every 20° longitude by 6° latitude. Carbon flux has slightly longer zonal scales, and requires a coverage of approximately 30° by 6°. Heat flux has much longer scales, and thus a platform distribution of approximately 90° by 10° would be sufficient. Fluxes, however, have significant subseasonal variability. For all fields, and especially fluxes, sustained measurements in time are required to prevent aliasing of the eddy signals into the longer climate scale signals. Our results imply a minimum of 100 biogeochemical-Argo floats are required to monitor the Southern Ocean carbon and heat content and air-sea exchanges on time-scales longer than 90 days. However, an estimate of formal mapping error using the current Argo array implies that in practice even an array of 600 floats (a nominal float density of about 1 every 7° longitude by 3° latitude) will result in nonnegligible uncertainty in estimating climate signals.

  18. Chain-length-dependent intermolecular packing in polyphenylenes: a high pressure study

    CERN Document Server

    Heimel, G; Oehzelt, M; Hummer, K; Koppelhuber-Bitschnau, B; Porsch, F; Ambrosch-Draxl, C; Resel, R

    2003-01-01

    We report on pressure-induced structural changes in crystalline oligo(para-phenylenes) containing two to six phenyl rings. The results are discussed with particular emphasis put on the implications these changes in intermolecular distances and molecular arrangement have on important bulk properties of this class of materials, such as optical response and charge transport. We performed energy dispersive x-ray diffraction in a systematic study on polycrystalline powders of biphenyl, para-terphenyl, p-quaterphenyl, p-quinquephenyl and p-sexiphenyl under hydrostatic pressure up to 60 kbar. Revisiting the crystal structures at ambient conditions reveals details in the packing principle. A linear relationship between the density at ambient conditions and the number of phenyl rings is found. High pressure data not only yields pressure-dependent lattice parameters and hints towards pressure-induced changes in the molecular arrangement but also allows for an analysis of the equations of state of these substances as a ...

  19. Evolution of deformation heterogeneity at multiple length scales in a strongly textured zinc layer on galvanized steel

    International Nuclear Information System (INIS)

    Ghosh, A; Gurao, N P

    2015-01-01

    The evolution of heterogeneity of plastic deformation in a zinc layer has been probed at multiple length scales using a battery of characterization tools like X-ray diffraction, electron back scatter diffraction (EBSD) and digital image correlation. The experimental results indicate that plastic deformation is heterogeneous at different length scales and the value of micro, meso and macro strain by different characterization techniques shows a different value. The value of strain determined at the meso and micro length scale from EBSD and X-ray diffraction was negligible, however, the macro-strain as determined from X-ray peak shift was significant. EBSD results showed evidence of profuse {101-bar2} <101-bar1> contraction twinning in the zinc layer with higher intragranular misorientation in the twin compared to the matrix. It is therefore, inferred that the evolution of higher intergranular (between matrix and twin) strain due to prolific contraction twinning contributes to the failure of zinc layer on galvanized steel. (paper)

  20. Cycle length dependence of the chronotropic effects of adrenaline, acetylcholine, Ca2+ and Mg2+ in the Guinea-pig sinoatrial node

    NARCIS (Netherlands)

    Opthof, T.; de Jonge, B.; Schade, B.; Jongsma, H. J.; Bouman, L. N.

    1984-01-01

    Ca (1.1-5.5 mM) has a positive chronotropic action on isolated right atria of the guinea-pig. The magnitude of the response depends on the cycle length. Magnitude and cycle length dependence of the Ca response are independent of beta-blockade by propranolol. Mg (0.6-6.0 mM) has a negative

  1. QTc interval length and QT dispersion as predictors of mortality in patients with non-insulin-dependent diabetes

    DEFF Research Database (Denmark)

    Christensen, P K; Gall, M A; Major-Pedersen, A

    2000-01-01

    Patients with non-insulin-dependent diabetes (NIDDM) are at independent risk of cardiovascular death. The reason is only partially understood. The aim of our study was therefore to evaluate the impact of corrected QT interval length (QTc) and QT dispersion (QT-disp) on mortality in a cohort of 324.......01), retinopathy (ptreatment (p.... Our study showed a high prevalence of QTc and QT-disp abnormalities and indicated that QTc-max but not QT-disp is an independent predictor of all cause and cardiovascular mortality in NIDDM patients....

  2. 2-Heptanone Produces Sensorial-Emotional Changes, Depending on Length of Exposure

    Directory of Open Access Journals (Sweden)

    Ana G. Gutiérrez-García

    2015-07-01

    Full Text Available 2-Heptanone is an alarm pheromone contained in some human fluids, but its role is unknown in chemical communication. In part one of this study, a sample of 24 women provided urine specimens taken around their supposed ovulation days, and a second sample 12 days later. As exclusion criteria, women with anxiety (based on the State-Trait Anxiety Inventory, Spielberger, mood disorders (based on the Clinical Diagnosis of Depression Questionnaire, and premenstrual dysphoric disorder (based on the Daily Symptoms Report were not included in the study. Gas chromatography/mass spectrometry indicated that urinary 2-heptanone content was increased approximately two-fold during pre-menstruation compared with the days around ovulation. In part two of this study, 141 male and female volunteers, sniffed this ketone and with a simple questionnaire it was determined that the longest tested duration (180 s of sniffing 2-heptanone lowered the acceptance of sniffing this ketone again, compared with the shorter sniffing durations (5 and 60 s, with no differences between sexes. The increased concentration of 2-heptanone during the day before menstruation may be considered as part of the functional changes preceding menstruation and sniffing this ketone may produce sensorial-emotional changes depending on time of sniffing, the significance of this deserves further study.

  3. On the length dependence of bridge-mediated electron transfer reactions

    International Nuclear Information System (INIS)

    Petrov, E.G.; Shevchenko, Ye.V.; May, V.

    2003-01-01

    Bridge-mediated nonadiabatic donor-acceptor (D-A) electron transfer (ET) is studied for the case of a regular molecular bridge of N identical units. It is shown that the multi-exponential ET kinetics reduces to a single-exponential transfer if, and only if, the integral population of the bridge remains small (less than 10 -2 ). An analytical expression for the overall D-A ET rate is derived and the necessary and sufficient conditions are formulated at which the rate is given as a sum of a superexchange and a sequential contribution. To describe experimental data on the N-dependence of ET reactions an approximate form of the overall transfer rate is derived. This expression is used to reproduce experimental data on distant ET through polyproline chains. Finally it is noted that the obtained analytical results can also be used for the description of more complex two-electron transfer reactions if the latter comprises separate single-electron pathways

  4. Long-gauge length embedded fiber optic ultrasonic sensor for large-scale concrete structures

    Science.gov (United States)

    Yuan, Libo; Zhou, Limin; Jin, Wei

    2004-02-01

    A fiber optic ultrasonic sensor based on Fizeau interferometer has been developed and demonstrated. A helium-neon laser light source with wavelength 0.6328 μm is used in our experiment. A special feature is its Fizeau configuration, which enables one to eliminate much undesirable noise by combining both the reference arm and the sensing arm within the same length of fiber. The dynamic response model of photo-elastic effect of ultrasonic wave and optical fiber is established. The fiber optic ultrasonic sensor experimental results are obtained and compared with the convenient PZT transducer.

  5. Anomaly in the Chain Length Dependence of n-Alkane Diffusion in ZIF-4 Metal-Organic Frameworks.

    Science.gov (United States)

    Hwang, Seungtaik; Gopalan, Arun; Hovestadt, Maximilian; Piepenbreier, Frank; Chmelik, Christian; Hartmann, Martin; Snurr, Randall Q; Kärger, Jörg

    2018-03-15

    Molecular diffusion is commonly found to slow down with increasing molecular size. Deviations from this pattern occur in some host materials with pore sizes approaching the diameters of the guest molecules. A variety of theoretical models have been suggested to explain deviations from this pattern, but robust experimental data are scarcely available. Here, we present such data, obtained by monitoring the chain length dependence of the uptake of n- alkanes in the zeolitic imidazolate framework ZIF-4. A monotonic decrease in diffusivity from ethane to n- butane was observed, followed by an increase for n- pentane, and another decrease for n- hexane. This observation was confirmed by uptake measurements with n- butane/ n -pentane mixtures, which yield faster uptake of n- pentane. Further evidence is provided by the observation of overshooting effects, i.e., by transient n- pentane concentrations exceeding the (eventually attained) equilibrium value. Accompanying grand canonical Monte Carlo simulations reveal, for the larger n- alkanes, significant differences between the adsorbed and gas phase molecular configurations, indicating strong confinement effects within ZIF-4, which, with increasing chain length, may be expected to give rise to configurational shifts facilitating molecular propagation at particular chain lengths.

  6. Anomaly in the Chain Length Dependence of n-Alkane Diffusion in ZIF-4 Metal-Organic Frameworks

    Directory of Open Access Journals (Sweden)

    Seungtaik Hwang

    2018-03-01

    Full Text Available Molecular diffusion is commonly found to slow down with increasing molecular size. Deviations from this pattern occur in some host materials with pore sizes approaching the diameters of the guest molecules. A variety of theoretical models have been suggested to explain deviations from this pattern, but robust experimental data are scarcely available. Here, we present such data, obtained by monitoring the chain length dependence of the uptake of n-alkanes in the zeolitic imidazolate framework ZIF-4. A monotonic decrease in diffusivity from ethane to n-butane was observed, followed by an increase for n-pentane, and another decrease for n-hexane. This observation was confirmed by uptake measurements with n-butane/n-pentane mixtures, which yield faster uptake of n-pentane. Further evidence is provided by the observation of overshooting effects, i.e., by transient n-pentane concentrations exceeding the (eventually attained equilibrium value. Accompanying grand canonical Monte Carlo simulations reveal, for the larger n-alkanes, significant differences between the adsorbed and gas phase molecular configurations, indicating strong confinement effects within ZIF-4, which, with increasing chain length, may be expected to give rise to configurational shifts facilitating molecular propagation at particular chain lengths.

  7. On the performance of a generic length scale turbulence model within an adaptive finite element ocean model

    Science.gov (United States)

    Hill, Jon; Piggott, M. D.; Ham, David A.; Popova, E. E.; Srokosz, M. A.

    2012-10-01

    Research into the use of unstructured mesh methods for ocean modelling has been growing steadily in the last few years. One advantage of using unstructured meshes is that one can concentrate resolution where it is needed. In addition, dynamic adaptive mesh optimisation (DAMO) strategies allow resolution to be concentrated when this is required. Despite the advantage that DAMO gives in terms of improving the spatial resolution where and when required, small-scale turbulence in the oceans still requires parameterisation. A two-equation, generic length scale (GLS) turbulence model (one equation for turbulent kinetic energy and another for a generic turbulence length-scale quantity) adds this parameterisation and can be used in conjunction with adaptive mesh techniques. In this paper, an implementation of the GLS turbulence parameterisation is detailed in a non-hydrostatic, finite-element, unstructured mesh ocean model, Fluidity-ICOM. The implementation is validated by comparing to both a laboratory-scale experiment and real-world observations, on both fixed and adaptive meshes. The model performs well, matching laboratory and observed data, with resolution being adjusted as necessary by DAMO. Flexibility in the prognostic fields used to construct the error metric used in DAMO is required to ensure best performance. Moreover, the adaptive mesh models perform as well as fixed mesh models in terms of root mean square error to observation or theoretical mixed layer depths, but uses fewer elements and hence has a reduced computational cost.

  8. DNA interactions with a Methylene Blue redox indicator depend on the DNA length and are sequence specific.

    Science.gov (United States)

    Farjami, Elaheh; Clima, Lilia; Gothelf, Kurt V; Ferapontova, Elena E

    2010-06-01

    A DNA molecular beacon approach was used for the analysis of interactions between DNA and Methylene Blue (MB) as a redox indicator of a hybridization event. DNA hairpin structures of different length and guanine (G) content were immobilized onto gold electrodes in their folded states through the alkanethiol linker at the 5'-end. Binding of MB to the folded hairpin DNA was electrochemically studied and compared with binding to the duplex structure formed by hybridization of the hairpin DNA to a complementary DNA strand. Variation of the electrochemical signal from the DNA-MB complex was shown to depend primarily on the DNA length and sequence used: the G-C base pairs were the preferential sites of MB binding in the duplex. For short 20 nts long DNA sequences, the increased electrochemical response from MB bound to the duplex structure was consistent with the increased amount of bound and electrochemically readable MB molecules (i.e. MB molecules that are available for the electron transfer (ET) reaction with the electrode). With longer DNA sequences, the balance between the amounts of the electrochemically readable MB molecules bound to the hairpin DNA and to the hybrid was opposite: a part of the MB molecules bound to the long-sequence DNA duplex seem to be electrochemically mute due to long ET distance. The increasing electrochemical response from MB bound to the short-length DNA hybrid contrasts with the decreasing signal from MB bound to the long-length DNA hybrid and allows an "off"-"on" genosensor development.

  9. Introduction of the Abbreviated Westmead Post-Traumatic Amnesia Scale and Impact on Length of Stay

    NARCIS (Netherlands)

    Watson, C. E.; Clous, E. A.; Jaeger, M.; D'Amours, S. K.

    2017-01-01

    Mild traumatic brain injury is a common presentation to Emergency Departments. Early identification of patients with cognitive deficits and provision of discharge advice are important. The Abbreviated Westmead Post-traumatic Amnesia Scale provides an early and efficient assessment of post-traumatic

  10. Membrane undulations in a structured fluid: Universal dynamics at intermediate length and time scales.

    Science.gov (United States)

    Granek, Rony; Diamant, Haim

    2018-01-05

    The dynamics of membrane undulations inside a viscous solvent is governed by distinctive, anomalous, power laws. Inside a viscoelastic continuous medium these universal behaviors are modified by the specific bulk viscoelastic spectrum. Yet, in structured fluids the continuum limit is reached only beyond a characteristic correlation length. We study the crossover to this asymptotic bulk dynamics. The analysis relies on a recent generalization of the hydrodynamic interaction in structured fluids, which shows a slow spatial decay of the interaction toward the bulk limit. For membranes which are weakly coupled to the structured medium we find a wide crossover regime characterized by different, universal, dynamic power laws. We discuss various systems for which this behavior is relevant, and delineate the time regime over which it may be observed.

  11. Reduced 3d modeling on injection schemes for laser wakefield acceleration at plasma scale lengths

    Science.gov (United States)

    Helm, Anton; Vieira, Jorge; Silva, Luis; Fonseca, Ricardo

    2017-10-01

    Current modelling techniques for laser wakefield acceleration (LWFA) are based on particle-in-cell (PIC) codes which are computationally demanding. In PIC simulations the laser wavelength λ0, in μm-range, has to be resolved over the acceleration lengths in meter-range. A promising approach is the ponderomotive guiding center solver (PGC) by only considering the laser envelope for laser pulse propagation. Therefore only the plasma skin depth λp has to be resolved, leading to speedups of (λp /λ0) 2. This allows to perform a wide-range of parameter studies and use it for λ0 Tecnologia (FCT), Portugal, through Grant No. PTDC/FIS-PLA/2940/2014 and PD/BD/105882/2014.

  12. The role of discharge variation in scaling of drainage area and food chain length in rivers

    Science.gov (United States)

    Sabo, John L.; Finlay, Jacques C.; Kennedy, Theodore A.; Post, David M.

    2010-01-01

    Food chain length (FCL) is a fundamental component of food web structure. Studies in a variety of ecosystems suggest that FCL is determined by energy supply, environmental stability, and/or ecosystem size, but the nature of the relationship between environmental stability and FCL, and the mechanism linking ecosystem size to FCL, remain unclear. Here we show that FCL increases with drainage area and decreases with hydrologic variability and intermittency across 36 North American rivers. Our analysis further suggests that hydrologic variability is the mechanism underlying the correlation between ecosystem size and FCL in rivers. Ecosystem size lengthens river food chains by integrating and attenuating discharge variation through stream networks, thereby enhancing environmental stability in larger river systems.

  13. Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

    KAUST Repository

    Fiscaletti, D.

    2016-10-24

    The scale dependence of the statistical alignment tendencies of the eigenvectors of the strain-rate tensor e(i), with the vorticity vector omega, is examined in the self-preserving region of a planar turbulent mixing layer. Data from a direct numerical simulation are filtered at various length scales and the probability density functions of the magnitude of the alignment cosines between the two unit vectors vertical bar e(i) . (omega) over cap vertical bar are examined. It is observed that the alignment tendencies are insensitive to the concurrent large-scale velocity fluctuations, but are quantitatively affected by the nature of the concurrent large-scale velocity-gradient fluctuations. It is confirmed that the small-scale (local) vorticity vector is preferentially aligned in parallel with the large-scale (background) extensive strain-rate eigenvector e(1), in contrast to the global tendency for omega to be aligned in parallelwith the intermediate strain-rate eigenvector [Hamlington et al., Phys. Fluids 20, 111703 (2008)]. When only data from regions of the flow that exhibit strong swirling are included, the so-called high-enstrophy worms, the alignment tendencies are exaggerated with respect to the global picture. These findings support the notion that the production of enstrophy, responsible for a net cascade of turbulent kinetic energy from large scales to small scales, is driven by vorticity stretching due to the preferential parallel alignment between omega and nonlocal e(1) and that the strongly swirling worms are kinematically significant to this process.

  14. The Accuracy of the Digital imaging system and the frequency dependent type apex locator in root canal length measurement

    International Nuclear Information System (INIS)

    Lee, Byoung Rib; Park, Chang Seo

    1998-01-01

    In order to achieve a successful endodontic treatment, root canals must be obturated three-dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora (digital imaging system) and Root ZX (the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems, whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with no 15, no 20, no 25 files by 3 different dentists each using the periapical radiography, Digora and Root ZX. The measurements were then compared with the true length. The results were as follows ; 1. In comparing mean discrepancies between measurements obtained by using periapical radiography (mean error : -0.449 ± 0.444 mm), Digora (mean error : -0.417 ± 0.415 mm) and Root ZX (mean error : 0.123 ± 0.458 mm) with true length, periapical radiography and Digora system had statistically significant differences (p 0.05). 2. By subtracting values obtained by using periapical radiography, Digora and Root ZX from the true length and making a distribution table of their absolute values, the following analysis was possible. In the case of periapical film, 140 out of 261 (53.6%) were clinically acceptable satisfying the margin of error of less than 0.5 mm, 151 out of 261 (53,6%) were acceptable in the Digora system while Root ZX had 197 out of 261 (75.5%) within the limits of 0.5 mm margin of error. 3. In determining whether the thickness of

  15. The Accuracy of the Digital imaging system and the frequency dependent type apex locator in root canal length measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byoung Rib; Park, Chang Seo [Dept. of Dental Radiology, College of Dentistry, Yensei University, Seoul (Korea, Republic of)

    1998-08-15

    In order to achieve a successful endodontic treatment, root canals must be obturated three-dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora (digital imaging system) and Root ZX (the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems, whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with no 15, no 20, no 25 files by 3 different dentists each using the periapical radiography, Digora and Root ZX. The measurements were then compared with the true length. The results were as follows; 1. In comparing mean discrepancies between measurements obtained by using periapical radiography (mean error : -0.449 {+-} 0.444 mm), Digora (mean error : -0.417 {+-} 0.415 mm) and Root ZX (mean error : 0.123 {+-} 0.458 mm) with true length, periapical radiography and Digora system had statistically significant differences (p<0.05) in most cases while root zx showed none (p>0.05). 2. By subtracting values obtained by using periapical radiography, Digora and Root ZX from the true length and making a distribution table of their absolute values, the following analysis was possible. In the case of periapical film, 140 out of 261 (53.6%) were clinically acceptable satisfying the margin of error of less than 0.5 mm, 151 out of 261 (53,6%) were acceptable in the Digora system while Root ZX had 197 out of 261 (75.5%) within the limits of 0.5 mm

  16. Seasonal dependence of large-scale Birkeland currents

    International Nuclear Information System (INIS)

    Fujii, R.; Iijima, T.; Potemra, T.A.; Sugiura, M.

    1981-01-01

    The seasonal dependence of large-scale Birkeland currents has been determined from the analysis of vector magnetic field data acquired by the TRIAD satellite in the northern hemisphere. Statistical characteristics of single sheet (i.e., net currents) and double sheet Birkeland currents were determined from 555 TRIAD passes during the summer, and 408 passes during the winter (more complicated multiple-sheet current systems were not included in this study). The average K/sub p/ value for the summer events is 1.9 and for the winter events is 2.0. The principal results include the following: (1) The single sheet Birkeland currents are statistically observed more often than the double sheet currents in the dayside of the auroral zone during any season. The single sheet currents are also observed more often in the summer than in the winter (as much as 2 to 3 times as often depending upon the MLT sector). (2) The intensities of the single and double sheet Birkeland currents on the dayside, from approximately 1000 MLT to 1800 MLT, are larger during the summer (in comparison to winter) by a factor of about 2. (3) The intensities of the double sheet Birkeland currents in the nightside (the dominant system in this local time) do not show a significant difference from summer to winter. (4) The single and double sheet currents in the dayside (between 0600 and 1800 MLT) appear at higher latitudes (by about 1 0 to 3 0 ) during the summer in comparison to the winter. These characterisctis suggest that the Birkeland current intensities are controlled by the ionosphere conductivity in the polar region. The greater occurrence of single sheet Birkeland currents during the summertime supports the suggestion that these currents close via the polar cap when the conductivity there is sufficiently high to permit it

  17. The Sensitivity of Income Polarization - Time, length of accounting periods, equivalence scales, and income definitions

    DEFF Research Database (Denmark)

    Azhar, Hussain

    This study looks at polarization and its components’ sensitivity to assumptions about equivalence scales, income definition, ethical income distribution parameters, and the income accounting period. A representative sample of Danish individual incomes from 1984 to 2002 is utilised. Results show...... that polarization has increased over time, regardless of the applied measure, when the last part of the period is compared to the first part of the period. Primary causes being increased inequality (alienation) and faster income growth among high incomes relative to those in the middle of the distribution...

  18. Evolutionary Models of Red Supergiants: Evidence for A Metallicity-dependent Mixing Length and Implications for Type IIP Supernova Progenitors

    Science.gov (United States)

    Chun, Sang-Hyun; Yoon, Sung-Chul; Jung, Moo-Keon; Kim, Dong Uk; Kim, Jihoon

    2018-01-01

    Recent studies on the temperatures of red supergiants (RSGs) in the local universe provide us with an excellent observational constraint on RSG models. We calibrate the mixing length parameter by comparing model predictions with the empirical RSG temperatures in Small and Large Magellanic Clouds, Milky Way, and M31, which are inferred from the TiO band and the spectral energy distribution (SED). Although our RSG models are computed with the MESA code, our result may be applied to other stellar evolution codes, including the BEC and TWIN codes. We find evidence that the mixing length increases with increasing metallicity for both cases where the TiO and SED temperatures of RSGs are used for the calibration. Together with the recent finding of a similar correlation in low-mass red giants by Tayar et al., this implies that the metallicity dependence of the mixing length is a universal feature in post-main sequence stars of both low and high masses. Our result implies that typical Type IIP supernova (SN IIP) progenitors with initial masses of ∼ 10{--}16 {M}ȯ have a radius range of 400 {R}ȯ ≲ R≲ 800 {R}ȯ regardless of metallicity. As an auxiliary result of this study, we find that the hydrogen-rich envelope mass of SN IIP progenitors for a given initial mass is predicted to be largely independent of metallicity if the Ledoux criterion with slow semiconvection is adopted, while the Schwarzschild models predict systematically more massive hydrogen-rich envelopes for lower metallicity.

  19. Antiaromatic bisindeno-[n]thienoacenes with small singlet biradical characters: Syntheses, structures and chain length dependent physical properties

    KAUST Repository

    Shi, Xueliang

    2014-01-01

    Recent studies demonstrated that aromaticity and biradical character play important roles in determining the ground-state structures and physical properties of quinoidal polycyclic hydrocarbons and oligothiophenes, a kind of molecular materials showing promising applications for organic electronics, photonics and spintronics. In this work, we designed and synthesized a new type of hybrid system, the so-called bisindeno-[n]thienoacenes (n = 1-4), by annulation of quinoidal fused α-oligothiophenes with two indene units. The obtained molecules can be regarded as antiaromatic systems containing 4n π electrons with small singlet biradical character (y0). Their ground-state geometry and electronic structures were studied by X-ray crystallographic analysis, NMR, ESR and Raman spectroscopy, assisted by density functional theory calculations. With extension of the chain length, the molecules showed a gradual increase of the singlet biradical character accompanied by decreased antiaromaticity, finally leading to a highly reactive bisindeno[4]thienoacene (S4-TIPS) which has a singlet biradical ground state (y0= 0.202). Their optical and electronic properties in the neutral and charged states were systematically investigated by one-photon absorption, two-photon absorption, transient absorption spectroscopy, cyclic voltammetry and spectroelectrochemistry, which could be correlated to the chain length dependent antiaromaticity and biradical character. Our detailed studies revealed a clear structure-aromaticity-biradical character-physical properties-reactivity relationship, which is of importance for tailored material design in the future. This journal is

  20. Length-dependent charge generation from vertical arrays of high-aspect-ratio ZnO nanowires.

    Science.gov (United States)

    Rivera, Vivian Farías; Auras, Florian; Motto, Paolo; Stassi, Stefano; Canavese, Giancarlo; Celasco, Edvige; Bein, Thomas; Onida, Barbara; Cauda, Valentina

    2013-10-18

    Aqueous chemical growth of zinc oxide nanowires is a flexible and effective approach to obtain dense arrays of vertically oriented nanostructures with high aspect ratio. Herein we present a systematic study of the different synthesis parameters that influence the ZnO seed layer and thus the resulting morphological features of the free-standing vertically oriented ZnO nanowires. We obtained a homogeneous coverage of transparent conductive substrates with high-aspect-ratio nanowire arrays (length/diameter ratio of up to 52). Such nanostructured vertical arrays were examined to assess their electric and piezoelectric properties, and showed an electric charge generation upon mechanical compressive stress. The principle of energy harvesting with these nanostructured ZnO arrays was demonstrated by connecting them to an electronic charge amplifier and storing the generated charge in a series of capacitors. We found that the generated charge and the electrical behavior of the ZnO nanowires are strictly dependent on the nanowire length. We have shown the importance of controlling the morphological properties of such ZnO nanostructures for optimizing a nanogenerator device. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Muscle length-dependent contribution of motoneuron Cav1.3 channels to force production in model slow motor unit.

    Science.gov (United States)

    Kim, Hojeong

    2017-07-01

    Persistent inward current (PIC)-generating Ca v 1.3 channels in spinal motoneuron dendrites are thought to be actively recruited during normal behaviors. However, whether and how the activation of PIC channels influences force output of motor unit remains elusive. Here, building a physiologically realistic model of slow motor unit I demonstrated that force production induced by the PIC activation is much smaller for short than lengthened muscles during the regular firing of the motoneuron that transitions from the quiescent state by either a brief current pulse at the soma or a brief synaptic excitation at the dendrites. By contrast, the PIC-induced force potentiation was maximal for short muscles when the motoneuron switched from a stable low-frequency firing state to a stable high-frequency firing state by the current pulse at the soma. Under the synaptic excitation at the dendrites, however, the force could not be potentiated by the transitioning of the motoneuron from a low- to a high-frequency firing state due to the simultaneous onset of PIC at the dendrites and firing at the soma. The strong dependency of the input-output relationship of the motor unit on the neuromodulation and Ia afferent inputs for the PIC channels was further shown under static variations in muscle length. Taken together, these findings suggest that the PIC activation in the motoneuron dendrites may differentially affect the force production of the motor unit, depending not only on the firing state history of the motoneuron and the variation in muscle length but also on the mode of motor activity. NEW & NOTEWORTHY Ca v 1.3 channels in motoneuron dendrites are actively involved during normal motor activities. To investigate the effects of the activation of motoneuron Ca v 1.3 channels on force production, a model motor unit was built based on best-available data. The simulation results suggest that force potentiation induced by Ca v 1.3 channel activation is strongly modulated not only by

  2. Independent and collective roles of surface structures at different length scales on pool boiling heat transfer

    Science.gov (United States)

    Li, Calvin H.; Rioux, Russell P.

    2016-01-01

    Spherical Cu nanocavity surfaces are synthesized to examine the individual role of contact angles in connecting lateral Rayleigh-Taylor wavelength to vertical Kevin-Helmholtz wavelength on hydrodynamic instability for the onset of pool boiling Critical Heat Flux (CHF). Solid and porous Cu pillar surfaces are sintered to investigate the individual role of pillar structure pitch at millimeter scale, named as module wavelength, on hydrodynamic instability at CHF. Last, spherical Cu nanocavities are coated on the porous Cu pillars to create a multiscale Cu structure, which is studied to examine the collective role and relative significance of contact angles and module wavelength on hydrodynamic instability at CHF, and the results indicate that module wavelength plays the dominant role on hydrodynamic instability at CHF when the height of surface structures is equal or above ¼ Kelvin-Helmholtz wavelength. Pool boiling Heat Transfer Coefficient (HTC) enhancements on spherical Cu nanocavity surfaces, solid and porous Cu pillar surfaces, and the integrated multiscale structure have been investigated, too. The experimental results reveal that the nanostructures and porous pillar structures can be combined together to achieve even higher enhancement of HTC than that of individual structures. PMID:27841322

  3. Role of Length Scales on Environmental Performance Metrics for Statistical Characterization of Well-Head Protection Regions

    Science.gov (United States)

    de Barros, F.; Guadagnini, A.; Fernandez-Garcia, D.; Riva, M.; Sanchez-Vila, X.

    2012-12-01

    We address the value of typically available hydrogeological information on environmental performance metrics (EPMs) as a function of several characteristic length scales that define groundwater flow and nonreactive solute transport in the presence of a pumping well. Improvement in the delineation of the well region of influence and reduction of the uncertainty associated with transport predictions is usually performed by means of hydrogeological sampling campaigns. We model aquifer heterogeneity through a spatially random hydraulic conductivity distribution and assess the ensuing uncertainty associated with predictions of key transport quantities conditioned to the probability that a distributed contaminant spill is captured by the well. We focus on the assessment of the impact of the acquisition of typical hydrogeological data on the reduction of uncertainty linked to the environmental scenario analyzed. We present a numerical investigation of the significance of the amount of available transmissivity measurements to yield predictions at a desired level of uncertainty of the following EPMs: (a) characteristic solute residence times in the system, and (b) the total mass exceeding a given threshold which is recovered by the well. We elucidate the role of the main (dimensionless) length scales that define and control the uncertainty associated with the target EPMs and infer a probabilistic model characterizing such uncertainty.

  4. Beam displacement as a function of temperature and turbulence length scale at two different laser radiation wavelengths.

    Science.gov (United States)

    Isterling, William M; Dally, Bassam B; Alwahabi, Zeyad T; Dubovinsky, Miro; Wright, Daniel

    2012-01-01

    Narrow laser beams directed from aircraft may at times pass through the exhaust plume of the engines and potentially degrade some of the laser beam characteristics. This paper reports on controlled studies of laser beam deviation arising from propagation through turbulent hot gases, in a well-characterized laboratory burner, with conditions of relevance to aircraft engine exhaust plumes. The impact of the temperature, laser wavelength, and turbulence length scale on the beam deviation has been investigated. It was found that the laser beam displacement increases with the turbulent integral length scale. The effect of temperature on the laser beam angular deviation, σ, using two different laser wavelengths, namely 4.67 μm and 632.8 nm, was recorded. It was found that the beam deviation for both wavelengths may be semiempirically modeled using a single function of the form, σ=a(b+(1/T)(2))(-1), with two parameters only, a and b, where σ is in microradians and T is the temperature in °C. © 2012 Optical Society of America

  5. Scale-dependence of hydraulic properties observed in fractured sedimentary rocks through large scale pumping test

    Science.gov (United States)

    Guihéneuf, N.; Dausse, A.; de Dreuzy, J. R.; Cherry, J. A.; Parker, B. L.

    2016-12-01

    Predicting flow in fractured reservoirs remains challenging as it highly depends on hydraulic connectivity of fractures which can vary from point to point. Classical pumping experiments conducted in fractured reservoirs often display fractional flow and anomalous slow diffusion due to bottlenecks or dead zones, characteristic of heterogeneity. In order to investigate reservoir properties at a contaminated site in the Simi Hills (South California, USA), composed by sandstones (dominant calcite cement) inter-bedded with fine-grained formations (shales, siltstones and mudstones), a large scale pumping test was performed in a major fault over 151 days. Deconvolution was applied first to remove the effect of variable flow rates and obtain constant-rate responses of the reservoir. Next, pressure-transients were analyzed both in time and space to get flow dimension, n, through the pressure derivative and extract the anomalous diffusion exponent, dw, as well as the fractal dimension, df. Analysis revealed at least two kinds of responses characterized by flow dimensions of 0.08 and 0.39 and anomalous diffusion exponents of 2.16 and 2.93, respectively. These properties, which can be related to major geological structures (i.e. major faults and surrounding fractures network), shows decreasing hydraulic properties (transmissivity, T, and storativity, S), and consequently, decreasing hydraulic connectivity, with increasing scale of investigation. In particular, the major fault (n = 0.39 ; dw = 2.93) shows a relationship of about T S3 with T r-1.36 and S r-0.43, consistent with flow within a fracture, while the surrounding fractures network (n = 0.08 ; dw = 2.16) displays a relationship which follow T S with T r-1.07 and S r-0.91. This scale-dependence of hydraulic properties may help improve groundwater flow prediction in such fractured reservoirs and could be taken into account for long-term transport of contaminants at this site.

  6. Reliability and validity of the Severity of Dependence Scale for detecting cannabis dependence in frequent cannabis users

    NARCIS (Netherlands)

    van der Pol, Peggy; Liebregts, Nienke; de Graaf, Ron; Korf, Dirk J.; van den Brink, Wim; van Laar, Margriet

    2013-01-01

    The Severity of Dependence Scale (SDS) measures with five items the degree of psychological dependence on several illicit drugs, including cannabis. Its psychometric properties have not yet been examined in young adult frequent cannabis users, an eminently high-risk group for cannabis dependence.

  7. Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.

    2011-08-10

    The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.

  8. Nearly constant ratio between the proton inertial scale and the spectrum break length scale in the plasma beta range from 0.2 to 1.4 in the solar wind turbulence

    Science.gov (United States)

    Wang, X.; Tu, C. Y.; He, J.; Wang, L.

    2017-12-01

    The spectrum break at the ion scale of the solar wind magnetic fluctuations are considered to give important clue on the turbulence dissipation mechanism. Among several possible mechanisms, the most notable ones are the two mechanisms that related respectively with proton thermal gyro-radius and proton inertial length. However, no definite conclusion has been given for which one is more reasonable because the two parameters have similar values in the normal plasma beta range. Here we do a statistical study for the first time to see if the two mechanism predictions have different dependence on the solar wind velocity and on the plasma beta in the normal plasma beta range in the solar wind at 1 AU. From magnetic measurements by Wind, Ulysses and Messenger, we select 60 data sets with duration longer than 8 hours. We found that the ratio between the proton inertial scale and the spectrum break scale do not change considerably with both varying the solar wind speed from 300km/s to 800km/s and varying the plasma beta from 0.2 to 1.4. The average value of the ratio times 2pi is 0.46 ± 0.08. However, the ratio between the proton gyro-radius and the break scale changes clearly. This new result shows that the proton inertial scale could be a single factor that determines the break length scale and hence gives a strong evidence to support the dissipation mechanism related to it in the normal plasma beta range. The value of the constant ratio may relate with the dissipation mechanism, but it needs further theoretical study to give detailed explanation.

  9. Polyglutamine length-dependent toxicity from α1ACT in Drosophila models of spinocerebellar ataxia type 6

    Directory of Open Access Journals (Sweden)

    Wei-Ling Tsou

    2016-12-01

    Full Text Available Spinocerebellar ataxia type 6 (SCA6 is a neurodegenerative disease that results from abnormal expansion of a polyglutamine (polyQ repeat. SCA6 is caused by CAG triplet repeat expansion in the gene CACNA1A, resulting in a polyQ tract of 19-33 in patients. CACNA1A, a bicistronic gene, encodes the α1A calcium channel subunit and the transcription factor, α1ACT. PolyQ expansion in α1ACT causes degeneration in mice. We recently described the first Drosophila models of SCA6 that express α1ACT with a normal (11Q or hyper-expanded (70Q polyQ. Here, we report additional α1ACT transgenic flies, which express full-length α1ACT with a 33Q repeat. We show that α1ACT33Q is toxic in Drosophila, but less so than the 70Q version. When expressed everywhere, α1ACT33Q-expressing adults die earlier than flies expressing the normal allele. α1ACT33Q causes retinal degeneration and leads to aggregated species in an age-dependent manner, but at a slower pace than the 70Q counterpart. According to western blots, α1ACT33Q localizes less readily in the nucleus than α1ACT70Q, providing clues into the importance of polyQ tract length on α1ACT localization and its site of toxicity. We expect that these new lines will be highly valuable for future work on SCA6.

  10. Dependability of Two Scaling Approaches to Direct Behavior Rating Multi-Item Scales Assessing Disruptive Classroom Behavior

    Science.gov (United States)

    Volpe, Robert J.; Briesch, Amy M.

    2016-01-01

    This study examines the dependability of two scaling approaches for using a five-item Direct Behavior Rating multi-item scale to assess student disruptive behavior. A series of generalizability theory studies were used to compare a traditional frequency-based scaling approach with an approach wherein the informant compares a target student's…

  11. Ataxia rating scales are age-dependent in healthy children

    NARCIS (Netherlands)

    Brandsma, Rick; Spits, Anne H.; Kuiper, Marieke J.; Lunsing, Roelinka J.; Burger, Huibert; Kremer, Hubertus P.; Sival, Deborah A.

    AIM: To investigate ataxia rating scales in children for reliability and the effect of age and sex. METHOD: Three independent neuropaediatric observers cross-sectionally scored a set of paediatric ataxia rating scales in a group of 52 healthy children (26 males, 26 females) aged 4 to 16 years (mean

  12. Temperature dependence of fluctuation time scales in spin glasses

    DEFF Research Database (Denmark)

    Kenning, Gregory G.; Bowen, J.; Sibani, Paolo

    2010-01-01

    Using a series of fast cooling protocols we have probed aging effects in the spin glass state as a function of temperature. Analyzing the logarithmic decay found at very long time scales within a simple phenomenological barrier model, leads to the extraction of the fluctuation time scale of the s...

  13. Scale-dependent behavior of the foredune: Implications for barrier island response to storms and sea-level rise

    Science.gov (United States)

    Houser, Chris; Wernette, Phil; Weymer, Bradley A.

    2018-02-01

    The impact of storm surge on a barrier island tends to be considered from a single cross-shore dimension, dependent on the relative elevations of the storm surge and dune crest. However, the foredune is rarely uniform and can exhibit considerable variation in height and width at a range of length scales. In this study, LiDAR data from barrier islands in Texas and Florida are used to explore how shoreline position and dune morphology vary alongshore, and to determine how this variability is altered or reinforced by storms and post-storm recovery. Wavelet analysis reveals that a power law can approximate historical shoreline change across all scales, but that storm-scale shoreline change ( 10 years) and dune height exhibit similar scale-dependent variations at swash and surf zone scales (red noise at the smallest scales characteristic of diffusive systems, suggesting that it is possible that small-scale variations in dune height can be repaired through alongshore recovery and expansion if there is sufficient time between storms. However, the time required for dune recovery exceeds the time between storms capable of eroding and overwashing the dune. Correlation between historical shoreline retreat and the variance of the dune at swash and surf zone scales suggests that the persistence of the dune is an important control on transgression through island migration or shoreline retreat with relative sea-level rise.

  14. Predicting permeability of regular tissue engineering scaffolds: scaling analysis of pore architecture, scaffold length, and fluid flow rate effects.

    Science.gov (United States)

    Rahbari, A; Montazerian, H; Davoodi, E; Homayoonfar, S

    2017-02-01

    The main aim of this research is to numerically obtain the permeability coefficient in the cylindrical scaffolds. For this purpose, a mathematical analysis was performed to derive an equation for desired porosity in terms of morphological parameters. Then, the considered cylindrical geometries were modeled and the permeability coefficient was calculated according to the velocity and pressure drop values based on the Darcy's law. In order to validate the accuracy of the present numerical solution, the obtained permeability coefficient was compared with the published experimental data. It was observed that this model can predict permeability with the utmost accuracy. Then, the effect of geometrical parameters including porosity, scaffold pore structure, unit cell size, and length of the scaffolds as well as entrance mass flow rate on the permeability of porous structures was studied. Furthermore, a parametric study with scaling laws analysis of sample length and mass flow rate effects on the permeability showed good fit to the obtained data. It can be concluded that the sensitivity of permeability is more noticeable at higher porosities. The present approach can be used to characterize and optimize the scaffold microstructure due to the necessity of cell growth and transferring considerations.

  15. Large-scale amplification, cloning and sequencing of near full-length HIV-1 subtype C genomes.

    Science.gov (United States)

    Rousseau, Christine M; Birditt, Brian A; McKay, Angela R; Stoddard, Julia N; Lee, Tsan Chun; McLaughlin, Sherry; Moore, Sarah W; Shindo, Nice; Learn, Gerald H; Korber, Bette T; Brander, Christian; Goulder, Philip J R; Kiepiela, Photini; Walker, Bruce D; Mullins, James I

    2006-09-01

    Full-length HIV-1 genome sequencing provides important data needed to address several vaccine design, molecular epidemiologic and pathogenesis questions. A protocol is presented for obtaining near full-length genomes (NFLGs) from subjects infected with HIV-1 subtype C. This protocol was used to amplify NFLGs from 244 of 366 (67%) samples collected at two clinics in Durban, South Africa (SK and PS). Viral load was directly associated with frequency of successful NFLG amplification for both cohorts (PS; p = 0.005 and SK; p clones were obtained from all 244 NFLG-positive PCR products, and both strands of each genome were sequenced, using a primary set of 46 primers. These methods thus allow the large-scale collection of HIV-1 NFLGs from populations infected primarily with subtype C. The methods are readily adaptable to other HIV-1 subtypes, and provide materials for viral functional analyses and population-based molecular epidemiology studies that include analysis of viral genome chimerization.

  16. Length-scales of Slab-induced Asthenospheric Deformation from Geodynamic Modeling, Mantle Deformation Fabric, and Synthetic Shear Wave Splitting

    Science.gov (United States)

    Jadamec, M. A.; MacDougall, J.; Fischer, K. M.

    2017-12-01

    The viscosity structure of the Earth's interior is critically important, because it places a first order constraint on plate motion and mantle flow rates. Geodynamic models using a composite viscosity based on experimentally derived flow laws for olivine aggregates show that lateral viscosity variations emerge in the upper mantle due to the subduction dynamics. However, the length-scale of this transition is still not well understood. Two-dimensional numerical models of subduction are presented that investigate the effect of initial slab dip, maximum yield stress (slab strength), and viscosity formulation (Newtonian versus composite) on the emergent lateral viscosity variations in the upper-mantle and magnitude of slab-driven mantle flow velocity. Significant viscosity reductions occur in regions of large flow velocity gradients due to the weakening effect of the dislocation creep deformation mechanism. The dynamic reductions in asthenospheric viscosity (less than 1018 Pa s) occur within approximately 500 km from driving force of the slab, with peak flow velocities occurring in models with a lower yield stress (weaker slab) and higher stress exponent. This leads to a sharper definition of the rheological base of the lithosphere and implies lateral variability in tractions along the base of the lithosphere. As the dislocation creep mechanism also leads to mantle deformation fabric, we then examine the spatial variation in the LPO development in the asthenosphere and calculate synthetic shear wave splitting. The models show that olivine LPO fabric in the asthenosphere generally increases in alignment strength with increased proximity to the slab, but can be transient and spatially variable on small length scales. The vertical flow fields surrounding the slab tip can produce shear-wave splitting variations with back-azimuth that deviate from the predictions of uniform trench-normal anisotropy, a result that bears on the interpretation of complexity in shear

  17. On the appearance of acetylcholine receptors in denervated rat diaphragm, and its dependence on nerve stump length

    International Nuclear Information System (INIS)

    Uchitel, O.; Robbins, N.

    1978-01-01

    Acetylcholine (ACh) sensitivity and extrajunctional receptor distribution of the rat diaphragm were closely monitored during the early period following denervation. Both contracture in response to 10 μg/ml of ACh and extrajunctional binding of [ 125 I]alpha-bungarotoxin ([ 125 I]α-BTX) were first detectable 30 h after cutting the phrenic nerve in the thorax. If the nerve were cut more proximally, leaving a 3.5 cm distal nerve stump, the same level of ACh contracture and [ 125 I]α-BTX binding did not appear until 40 h after operation. This 10-h delay was far longer than the 3-h delay in transmission failure reportedly dependent on stump length. The earliest detectable extrajunctional [ 125 I]α-BTX binding appeared throughout the entire muscle fiber, and was not localized to the endplate region as would be expected if degeneration in the nerve terminal induced new receptors. However, later significant increases in [ 125 I]α-BTX binding at the endplate region could have resulted from such degeneration. All these results are consistent with neurotrophic regulation of muscle ACh receptors, working via a mechanism involving axonal transport. (Auth.)

  18. Time-dependent scaling patterns in high frequency financial data

    Science.gov (United States)

    Nava, Noemi; Di Matteo, Tiziana; Aste, Tomaso

    2016-10-01

    We measure the influence of different time-scales on the intraday dynamics of financial markets. This is obtained by decomposing financial time series into simple oscillations associated with distinct time-scales. We propose two new time-varying measures of complexity: 1) an amplitude scaling exponent and 2) an entropy-like measure. We apply these measures to intraday, 30-second sampled prices of various stock market indices. Our results reveal intraday trends where different time-horizons contribute with variable relative amplitudes over the course of the trading day. Our findings indicate that the time series we analysed have a non-stationary multifractal nature with predominantly persistent behaviour at the middle of the trading session and anti-persistent behaviour at the opening and at the closing of the session. We demonstrate that these patterns are statistically significant, robust, reproducible and characteristic of each stock market. We argue that any modelling, analytics or trading strategy must take into account these non-stationary intraday scaling patterns.

  19. Scale-dependent Hausdorff dimensions in 2d gravity

    Directory of Open Access Journals (Sweden)

    J. Ambjørn

    2014-09-01

    Full Text Available By appropriate scaling of coupling constants a one-parameter family of ensembles of two-dimensional geometries is obtained, which interpolates between the ensembles of (generalized causal dynamical triangulations and ordinary dynamical triangulations. We study the fractal properties of the associated continuum geometries and identify both global and local Hausdorff dimensions.

  20. Scale-dependent Hausdorff dimensions in 2d gravity

    Energy Technology Data Exchange (ETDEWEB)

    Ambjørn, J., E-mail: ambjorn@nbi.dk [Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen Ø (Denmark); Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radbaud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands); Budd, T., E-mail: budd@nbi.dk [Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen Ø (Denmark); Watabiki, Y., E-mail: watabiki@th.phys.titech.ac.jp [Tokyo Institute of Technology, Dept. of Physics, High Energy Theory Group, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2014-09-07

    By appropriate scaling of coupling constants a one-parameter family of ensembles of two-dimensional geometries is obtained, which interpolates between the ensembles of (generalized) causal dynamical triangulations and ordinary dynamical triangulations. We study the fractal properties of the associated continuum geometries and identify both global and local Hausdorff dimensions.

  1. Scale dependence and small-x behaviour of polarized parton distributions

    International Nuclear Information System (INIS)

    Ball, R.D.; Forte, S.; Ridolfi, G.

    1995-01-01

    We discuss perturbative evolution of the polarized structure function g 1 in the (x, Q 2 ) plane, with special regard to the small-x region. We determine g 1 in terms of polarized quark and gluon distributions using coefficient functions to order α s . At small x g 1 then displays substantial scale dependence, which necessarily implies a corresponding scale dependence in the large-x region. This scale dependence has significant consequences for the extraction of the first moment from the experimental data, reducing its value while increasing the error. Conversely, the scale dependence may be used to constrain the size of the polarized gluon distribution. ((orig.))

  2. On mechanics and material length scales of failure in heterogeneous interfaces using a finite strain high performance solver

    Science.gov (United States)

    Mosby, Matthew; Matouš, Karel

    2015-12-01

    Three-dimensional simulations capable of resolving the large range of spatial scales, from the failure-zone thickness up to the size of the representative unit cell, in damage mechanics problems of particle reinforced adhesives are presented. We show that resolving this wide range of scales in complex three-dimensional heterogeneous morphologies is essential in order to apprehend fracture characteristics, such as strength, fracture toughness and shape of the softening profile. Moreover, we show that computations that resolve essential physical length scales capture the particle size-effect in fracture toughness, for example. In the vein of image-based computational materials science, we construct statistically optimal unit cells containing hundreds to thousands of particles. We show that these statistically representative unit cells are capable of capturing the first- and second-order probability functions of a given data-source with better accuracy than traditional inclusion packing techniques. In order to accomplish these large computations, we use a parallel multiscale cohesive formulation and extend it to finite strains including damage mechanics. The high-performance parallel computational framework is executed on up to 1024 processing cores. A mesh convergence and a representative unit cell study are performed. Quantifying the complex damage patterns in simulations consisting of tens of millions of computational cells and millions of highly nonlinear equations requires data-mining the parallel simulations, and we propose two damage metrics to quantify the damage patterns. A detailed study of volume fraction and filler size on the macroscopic traction-separation response of heterogeneous adhesives is presented.

  3. Predicting length of stay in specialist neurological rehabilitation.

    Science.gov (United States)

    Taiwo, Whitney; Wressle, Alexandra; Bradley, Lloyd

    2018-03-01

    A retrospective case series was performed to determine which measures of complexity, dependency and function most accurately predict inpatient neurorehabilitation length of stay for individuals with post-acute neurological disorders. Sociodemographic, medical and functional variables were extracted from data submitted to the UK Rehabilitation Outcomes Collaborative. Length of stay was calculated as the total number of inpatient days, functional status was measured using Barthel Index, rehabilitation complexity was measured using Extended Rehabilitation Complexity Scale, and nursing dependency was measured using the Northwick Park Dependency Scale. The mean rehabilitation length of stay was 70.9 days, with length of stay being 35.1 days higher in inpatients with acquired brain injury than inpatients with spinal cord injury. Diagnostic category, Barthel Index scores, Extended Rehabilitation Complexity Scale scores and Northwick Park Dependency Scale scores at admission independently predicted length of stay. Multiple regressions including diagnostic group, Barthel Index, Extended Rehabilitation Complexity Scale and Northwick Park Dependency Scale statistically significantly predicted 37.9% of the variability in length of stay (p Scale on admission was most closely correlated with inpatient length of stay. In conclusion, inpatient length of stay is predicted by diagnostic category, Extended Rehabilitation Complexity Scale, Northwick Park Dependency Scale and Barthel Index. The most influential predictor of rehabilitation length of stay was Northwick Park Dependency Scale score at admission. These results may help facilitate rehabilitation resource planning and implementation of effective commissioning plans. Implications for Rehabilitation The most accurate predicting variable for length of stay in inpatient neurological rehabilitation was nursing need as measured by the Northwick Park Dependency Scale score on admission. Service users and commissioners can be

  4. The Radius and Entropy of a Magnetized, Rotating, Fully Convective Star: Analysis with Depth-dependent Mixing Length Theories

    Science.gov (United States)

    Ireland, Lewis G.; Browning, Matthew K.

    2018-04-01

    Some low-mass stars appear to have larger radii than predicted by standard 1D structure models; prior work has suggested that inefficient convective heat transport, due to rotation and/or magnetism, may ultimately be responsible. We examine this issue using 1D stellar models constructed using Modules for Experiments in Stellar Astrophysics (MESA). First, we consider standard models that do not explicitly include rotational/magnetic effects, with convective inhibition modeled by decreasing a depth-independent mixing length theory (MLT) parameter α MLT. We provide formulae linking changes in α MLT to changes in the interior specific entropy, and hence to the stellar radius. Next, we modify the MLT formulation in MESA to mimic explicitly the influence of rotation and magnetism, using formulations suggested by Stevenson and MacDonald & Mullan, respectively. We find rapid rotation in these models has a negligible impact on stellar structure, primarily because a star’s adiabat, and hence its radius, is predominantly affected by layers near the surface; convection is rapid and largely uninfluenced by rotation there. Magnetic fields, if they influenced convective transport in the manner described by MacDonald & Mullan, could lead to more noticeable radius inflation. Finally, we show that these non-standard effects on stellar structure can be fabricated using a depth-dependent α MLT: a non-magnetic, non-rotating model can be produced that is virtually indistinguishable from one that explicitly parameterizes rotation and/or magnetism using the two formulations above. We provide formulae linking the radially variable α MLT to these putative MLT reformulations.

  5. Characteristic length scale of the magnon accumulation in Fe{sub 3}O{sub 4}/Pt bilayer structures by incoherent thermal excitation

    Energy Technology Data Exchange (ETDEWEB)

    Anadón, A., E-mail: anadonb@unizar.es; Lucas, I.; Morellón, L. [Instituto de Nanociencia de Aragón, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Ramos, R. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Algarabel, P. A. [Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza and Consejo Superior de Investigaciones Científicas, 50009 Zaragoza (Spain); Ibarra, M. R.; Aguirre, M. H. [Instituto de Nanociencia de Aragón, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Laboratorio de Microscopías avanzadas, Universidad de Zaragoza, 50018 Zaragoza (Spain)

    2016-07-04

    The dependence of Spin Seebeck effect (SSE) with the thickness of the magnetic materials is studied by means of incoherent thermal excitation. The SSE voltage signal in Fe{sub 3}O{sub 4}/Pt bilayer structure increases with the magnetic material thickness up to 100 nm, approximately, showing signs of saturation for larger thickness. This dependence is well described in terms of a spin current pumped in the platinum film by the magnon accumulation in the magnetic material. The spin current is generated by a gradient of temperature in the system and detected by the Pt top contact by means of inverse spin Hall effect. Calculations in the frame of the linear response theory adjust with a high degree of accuracy the experimental data, giving a thermal length scale of the magnon accumulation (Λ) of 17 ± 3 nm at 300 K and Λ = 40 ± 10 nm at 70 K.

  6. Length-scales of chemical and isotopic heterogeneity in the mantle section of the Shetland Ophiolite Complex, Scotland

    Science.gov (United States)

    O'Driscoll, B.; Walker, R. J.; Clay, P. L.; Day, J. M. D.; Ash, R. D.; Daly, J. S.

    2018-04-01

    Kilometre to sub-metre scale heterogeneities have been inferred in the oceanic mantle based on sampling of both ophiolites and abyssal peridotites. The ∼492 Ma Shetland Ophiolite Complex (SOC) contains a well-preserved mantle section that is dominated by harzburgite (∼70 vol.%) previously reported to have variable major and trace element compositions, yet dominantly chondritic initial 187Os/188Os compositions. To assess the preservation of compositional heterogeneities at sub-metre length-scales in the oceanic mantle, a ∼45 m2 area of the SOC mantle section was mapped and sampled in detail. Harzburgites, dunites and a pyroxenite from this area were analysed for lithophile and highly-siderophile element (HSE) abundances, as well as for 187Os/188Os ratios. Lithophile element data for most rocks are characteristic of supra-subduction zone (SSZ) metasomatic processes. Two dunites have moderately fractionated HSE patterns and suprachondritic γOs(492 Ma) values (+5.1 and +7.5) that are also typical of ophiolitic dunites generated by SSZ melt-rock interactions. By contrast, six harzburgites and four dunites have approximately chondritic-relative abundances of Os, Ir and Ru, and γOs(492 Ma) values ranging only from -0.6 to +2.7; characteristics that imply no significant influence during SSZ processes. Two harzburgites are also characterised by significantly less radiogenic γOs(492 Ma) values (-3.5 and -4), and yield Mesoproterozoic time of Re depletion (TRD) model ages. The range of Os isotope compositions in the studied area is comparable to the range reported for a suite of samples representative of the entire SOC mantle section, and approaches the total isotopic variation of the oceanic mantle, as observed in abyssal peridotites. Mechanisms by which this heterogeneity can be formed and preserved involve inefficient and temporally distinct melt extraction events and strong localised channelling of these melts.

  7. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales.

    Science.gov (United States)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A L David; Belcher, Warwick J; Dastoor, Paul C

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  8. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    Science.gov (United States)

    Burke, Kerry B.; Stapleton, Andrew J.; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A. L. David; Belcher, Warwick J.; Dastoor, Paul C.

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  9. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    International Nuclear Information System (INIS)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C; Kilcoyne, A L David

    2011-01-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N ' -(4-butylphenyl)-bis-N, N ' -phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  10. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); Kilcoyne, A L David, E-mail: Paul.Dastoor@newcastle.edu.au [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N{sup '}-(4-butylphenyl)-bis-N, N{sup '}-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  11. Contact damage and fracture micromechanisms of multilayered TiN/CrN coatings at micro- and nano-length scales

    Energy Technology Data Exchange (ETDEWEB)

    Roa, J.J., E-mail: joan.josep.roa@upc.edu [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); CRnE, Universitat Politècnica de Catalunya, C. Pasqual i Vila 15, 08028 Barcelona (Spain); Jiménez-Piqué, E. [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); CRnE, Universitat Politècnica de Catalunya, C. Pasqual i Vila 15, 08028 Barcelona (Spain); Martínez, R. [Centro de Ingeniería Avanzada de Superfícies, Asociación de la Industria Navarra — AIN, Crta. Pamplona, 1, Edificio AIN, 31191 Cordovilla (Spain); Ramírez, G. [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); Fundació CTM Centre Tecnològic, Avda. Bases de Manresa 1, 08243 Manresa (Spain); Tarragó, J.M. [CIEFMA — Departament de Ciència dels Materials i Eng. Metallúrgica, Universitat Politècnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona (Spain); CRnE, Universitat Politècnica de Catalunya, C. Pasqual i Vila 15, 08028 Barcelona (Spain); and others

    2014-11-28

    In this study, systematic nanomechanical and micromechanical studies have been conducted in three multilayer TiN/CrN systems with different bilayer periods (8, 19 and 25 nm). Additionally, experimental work has been performed on corresponding TiN and CrN single layers, for comparison purposes. The investigation includes the use of different indenter tip geometries as well as contact loading conditions (i.e. indentation/scratch) such to induce different stress field and damage scenarios within the films. The surface and subsurface damage under the different indentation imprints and scratch tracks have been observed by atomic force microscopy, field emission scanning electron microscopy and focused ion beam. Multilayer TiN/CrN coated systems are found to exhibit higher adhesion strength (under sliding contact load) and cracking resistance (under spherical indentation) than those coated with reference TiN and CrN monolayers. The main reason behind these findings is the effective development of microstructurally-driven deformation and cracking resistant micromechanisms: rotation of columnar grains (and associated distortion of bilayer period) and crack deflection of interlayer thickness length scale, respectively. - Highlights: • Nanomechanical and micromechanical study in TiN/CrN systems • TiN/CrN coated systems exhibit higher adhesion strength and cracking resistance. • Main deformation and cracking micromechanisms: columnar grain rotation and crack deflection.

  12. Soft x-ray microscopy - a powerful analytical tool to image magnetism down to fundamental length and times scales

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Peter

    2008-08-01

    The magnetic properties of low dimensional solid state matter is of the utmost interest both scientifically as well as technologically. In addition to the charge of the electron which is the base for current electronics, by taking into account the spin degree of freedom in future spintronics applications open a new avenue. Progress towards a better physical understanding of the mechanism and principles involved as well as potential applications of nanomagnetic devices can only be achieved with advanced analytical tools. Soft X-ray microscopy providing a spatial resolution towards 10nm, a time resolution currently in the sub-ns regime and inherent elemental sensitivity is a very promising technique for that. This article reviews the recent achievements of magnetic soft X-ray microscopy by selected examples of spin torque phenomena, stochastical behavior on the nanoscale and spin dynamics in magnetic nanopatterns. The future potential with regard to addressing fundamental magnetic length and time scales, e.g. imaging fsec spin dynamics at upcoming X-ray sources is pointed out.

  13. Surface physicochemical properties at the micro and nano length scales: role on bacterial adhesion and Xylella fastidiosa biofilm development.

    Science.gov (United States)

    Lorite, Gabriela S; Janissen, Richard; Clerici, João H; Rodrigues, Carolina M; Tomaz, Juarez P; Mizaikoff, Boris; Kranz, Christine; de Souza, Alessandra A; Cotta, Mônica A

    2013-01-01

    The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant.

  14. Is there scale-dependent bias in single-field inflation?

    International Nuclear Information System (INIS)

    De Putter, Roland; Doré, Olivier; Green, Daniel

    2015-01-01

    Scale-dependent halo bias due to local primordial non-Gaussianity provides a strong test of single-field inflation. While it is universally understood that single-field inflation predicts negligible scale-dependent bias compared to current observational uncertainties, there is still disagreement on the exact level of scale-dependent bias at a level that could strongly impact inferences made from future surveys. In this paper, we clarify this confusion and derive in various ways that there is exactly zero scale-dependent bias in single-field inflation. Much of the current confusion follows from the fact that single-field inflation does predict a mode coupling of matter perturbations at the level of f NL local ; ≈ −5/3, which naively would lead to scale-dependent bias. However, we show explicitly that this mode coupling cancels out when perturbations are evaluated at a fixed physical scale rather than fixed coordinate scale. Furthermore, we show how the absence of scale-dependent bias can be derived easily in any gauge. This result can then be incorporated into a complete description of the observed galaxy clustering, including the previously studied general relativistic terms, which are important at the same level as scale-dependent bias of order f NL local  ∼ 1. This description will allow us to draw unbiased conclusions about inflation from future galaxy clustering data

  15. Psychometric properties of the extended Care Dependency Scale for older persons in Egypt

    NARCIS (Netherlands)

    Boggatz, Thomas; Farid, Tamer; Mohammedin, Ahmed; Dijkstra, Ate; Lohrmann, Christa; Dassen, Theo

    2009-01-01

    Aim. The aim of this study was to determine the validity and reliability of the modified Arabic Care Dependency Scale for self-assessment of older persons in Egypt and to compare these self-assessments to proxy assessments by care givers and family members. Background. The Care Dependency Scale is

  16. Spatial dependencies between large-scale brain networks.

    Directory of Open Access Journals (Sweden)

    Robert Leech

    Full Text Available Functional neuroimaging reveals both increases (task-positive and decreases (task-negative in neural activation with many tasks. Many studies show a temporal relationship between task positive and task negative networks that is important for efficient cognitive functioning. Here we provide evidence for a spatial relationship between task positive and negative networks. There are strong spatial similarities between many reported task negative brain networks, termed the default mode network, which is typically assumed to be a spatially fixed network. However, this is not the case. The spatial structure of the DMN varies depending on what specific task is being performed. We test whether there is a fundamental spatial relationship between task positive and negative networks. Specifically, we hypothesize that the distance between task positive and negative voxels is consistent despite different spatial patterns of activation and deactivation evoked by different cognitive tasks. We show significantly reduced variability in the distance between within-condition task positive and task negative voxels than across-condition distances for four different sensory, motor and cognitive tasks--implying that deactivation patterns are spatially dependent on activation patterns (and vice versa, and that both are modulated by specific task demands. We also show a similar relationship between positively and negatively correlated networks from a third 'rest' dataset, in the absence of a specific task. We propose that this spatial relationship may be the macroscopic analogue of microscopic neuronal organization reported in sensory cortical systems, and that this organization may reflect homeostatic plasticity necessary for efficient brain function.

  17. The compositional similarity of urban forests among the world's cities is scale dependent

    Science.gov (United States)

    Jun Yang; Frank A. La Sorte; Petr Pysek; Pengbo Yan; David Nowak; Joe McBride

    2015-01-01

    Aim We examined species composition of urban forests from local to global scales using occurrence and abundance information to determine how compositional similarity is defined across spatial scales. We predicted that urban forests have become more homogeneous world-wide, which should result in minimal scale dependence that is more pronounced for non-native species,...

  18. Scale dependency of American marten (Martes americana) habitat relations [Chapter 12

    Science.gov (United States)

    Andrew J. Shirk; Tzeidle N. Wasserman; Samuel A. Cushman; Martin G. Raphael

    2012-01-01

    Animals select habitat resources at multiple spatial scales; therefore, explicit attention to scale-dependency when modeling habitat relations is critical to understanding how organisms select habitat in complex landscapes. Models that evaluate habitat variables calculated at a single spatial scale (e.g., patch, home range) fail to account for the effects of...

  19. Scale-dependent bi-trophic interactions in a semi-arid savanna

    NARCIS (Netherlands)

    Waal, van der Cornelis; Kroon, de Hans; Langevelde, van Frank; Boer, de Fred; Heitkonig, Ignas; Slotow, Rob; Pretorius, Yolanda; Prins, Herbert H.T.

    2016-01-01

    The scale of resource heterogeneity may influence how resources are locally partitioned between co-existing large and small organisms such as trees and grasses in savannas. Scale-related plant responses may, in turn, influence herbivore use of the vegetation. To examine these scale-dependent

  20. Diffusion effects on volume-selective NMR at small length scales; Diffusionseffekte in volumenselektiver NMR auf kleinen Laengenskalen

    Energy Technology Data Exchange (ETDEWEB)

    Gaedke, Achim

    2009-01-21

    In this thesis, the interplay between diffusion and relaxation effects in spatially selective NMR experiments at short length scales is explored. This is especially relevant in the context of both conventional and mechanically detected MRI at (sub)micron resolution in biological specimens. Recent results on selectively excited very thin slices showed an in-slice-magnetization recovery orders of magnitude faster than the longitudinal relaxation time T1. However, those experiments were run on fully relaxed samples while MRI and especially mechanically detected NMR experiments are typically run in a periodic fashion with repetition times far below T1. The main purpose of this work therefore was to extend the study of the interplay between diffusion and longitudinal relaxation to periodic excitations. In some way, this is inverse phenomenon to the DESIRE (Diffusive Enhancement of SIgnal and REsolution) approach, proposed 1992 by Lauterbur. Experiments on periodically excited thin slices were carried out at a dedicated static field gradient cryomagnet with magnetic field gradients up to 180 T/m. In order to obtain plane slices, an appropriate isosurface of the gradient magnet had to be identified. It was found at a field of 3.8 T with a gradient of 73 T/m. In this field, slices down to a thickness of 3.2 {mu}m could be excited. The detection of the NMR signal was done using FIDs instead of echoes as the excitation bandwidth of those thin slices is sufficiently small to observe FIDs which are usually considered to be elusive to detection in such strong static field gradients. A simulation toolbox based on the full Bloch-Torrey-equation was developed to describe the excitation and the formation of NMR signals under those unusual conditions as well as the interplay of diffusion and magnetization recovery. Both the experiments and the simulations indicate that diffusion effects lead to a strongly enhanced magnetization modulation signal also under periodic excitation

  1. An asymmetry in the phosphate dependence of tension transients induced by length perturbation in mammalian (rabbit psoas) muscle fibres.

    Science.gov (United States)

    Ranatunga, K W; Coupland, Moira E; Mutungi, G

    2002-08-01

    The effects of inorganic phosphate (P(i), a product released during ATP hydrolysis in active muscle) on tension transients induced by length perturbation (approximately 0.3 ms) were examined in chemically skinned (0.5 % Brij), maximally Ca(2+)-activated rabbit psoas muscle fibres at 10 degrees C (ionic strength 200 mM, pH 7.1). In one type of experiment, the tension transients induced by length release and stretch of a standard amplitude (0.4-0.5 % of L(o), muscle fibre length) were examined at a range of added [P(i)] (range 3-25 mM). The steady active tension was depressed approximately 45 % with 25 mM added P(i). The initial tension recovery (from T(1), extreme tension reached after length step, to T(2), tension after quick recovery) was analysed by half-time measurement and also by exponential curve fitting - extracting a fast (phase 2a) and a slow (phase 2b) component. The tension decay after a stretch became faster with increased [P(i)], whereas the quick tension rise induced by a length release was insensitive to added P(i). Consequently, the asymmetry in the speed of tension recovery from stretch and release was reduced at high [P(i)]. A plot of the phase 2b rate (or 1/half-time) of tension decay after stretch versus [P(i)] was approximately hyperbolic and showed saturation at higher [P(i)] levels. In a second type of experiment, the tension transients induced by length steps of different amplitudes were examined in control (no added P(i)) and in the presence of 25 mM added P(i). Over a range of length step amplitudes (up to 1 % L(0)), the tension decay after stretch was consistently faster in the presence of P(i) than in the control; this was particularly pronounced in phase 2b. The rate of tension rise after length release remained high but similar in the presence and absence of added P(i). These observations indicate that a stretch and release perturb different molecular steps in the crossbridge cycle. The P(i) sensitivity of tension decay (phase 2b

  2. Chain length-dependent effects of inulin-type fructan dietary fiber on human systemic immune responses against hepatitis-B

    NARCIS (Netherlands)

    Vogt, Leonie M; Elderman, Marlies E; Borghuis, Theo; de Haan, Bart J; Faas, Marijke M; de Vos, Paul

    2017-01-01

    Scope: In vivo studies demonstrating that only specific dietary-fibers contribute to immunity are still inconclusive, as measuring immune effects in healthy humans remains difficult. We applied a relatively inefficacious vaccination-challenge to study chain length-dependent effects of inulin-type

  3. Scaling model for a speed-dependent vehicle noise spectrum

    Directory of Open Access Journals (Sweden)

    Giovanni Zambon

    2017-06-01

    Full Text Available Considering the well-known features of the noise emitted by moving sources, a number of vehicle characteristics such as speed, unladen mass, engine size, year of registration, power and fuel were recorded in a dedicated monitoring campaign performed in three different places, each characterized by different number of lanes and the presence of nearby reflective surfaces. A full database of 144 vehicles (cars was used to identify statistically relevant features. In order to compare the vehicle transit noise in different environmental condition, all 1/3-octave band spectra were normalized and analysed. Unsupervised clustering algorithms were employed to group together spectrum levels with similar profiles. Our results corroborate the well-known fact that speed is the most relevant characteristic to discriminate between different vehicle noise spectrum. In keeping with this fact, we present a new approach to predict analytically noise spectra for a given vehicle speed. A set of speed-dependent analytical functions are suggested in order to fit the normalized average spectrum profile at different speeds. This approach can be useful for predicting vehicle speed based purely on its noise spectrum pattern. The present work is complementary to the accurate analysis of noise sources based on the beamforming technique.

  4. Morphology Dependent Flow Stress in Nickel-Based Superalloys in the Multi-Scale Crystal Plasticity Framework

    Directory of Open Access Journals (Sweden)

    Shahriyar Keshavarz

    2017-11-01

    Full Text Available This paper develops a framework to obtain the flow stress of nickel-based superalloys as a function of γ-γ’ morphology. The yield strength is a major factor in the design of these alloys. This work provides additional effects of γ’ morphology in the design scope that has been adopted for the model developed by authors. In general, the two-phase γ-γ’ morphology in nickel-based superalloys can be divided into three variables including γ’ shape, γ’ volume fraction and γ’ size in the sub-grain microstructure. In order to obtain the flow stress, non-Schmid crystal plasticity constitutive models at two length scales are employed and bridged through a homogenized multi-scale framework. The multi-scale framework includes two sub-grain and homogenized grain scales. For the sub-grain scale, a size-dependent, dislocation-density-based finite element model (FEM of the representative volume element (RVE with explicit depiction of the γ-γ’ morphology is developed as a building block for the homogenization. For the next scale, an activation-energy-based crystal plasticity model is developed for the homogenized single crystal of Ni-based superalloys. The constitutive models address the thermo-mechanical behavior of nickel-based superalloys for a large temperature range and include orientation dependencies and tension-compression asymmetry. This homogenized model is used to obtain the morphology dependence on the flow stress in nickel-based superalloys and can significantly expedite crystal plasticity FE simulations in polycrystalline microstructures, as well as higher scale FE models in order to cast and design superalloys.

  5. Different cellular response mechanisms contribute to the length-dependent cytotoxicity of multi-walled carbon nanotubes

    OpenAIRE

    Liu, Dun; Wang, Lijun; Wang, Zhigang; Cuschieri, Alfred

    2012-01-01

    To date, there has not been an agreement on the best methods for the characterisation of multi-walled carbon nanotube (MWCNT) toxicity. The length of MWCNTs has been identified as a factor in in vitro and in vivo studies, in addition to their purity and biocompatible coating. Another unresolved issue relates to the variable toxicity of MWCNTs on different cell types. The present study addressed the effects of MWCNTs' length on mammalian immune and epithelial cancer cells RAW264.7 and MCF-7, r...

  6. Accessible length scale of the in-plane structure in polarized neutron off-specular and grazing-incidence small-angle scattering measurements

    Science.gov (United States)

    Maruyama, R.; Bigault, T.; Wildes, A. R.; Dewhurst, C. D.; Saerbeck, T.; Honecker, D.; Yamazaki, D.; Soyama, K.; Courtois, P.

    2017-06-01

    Polarized neutron off-specular and grazing-incidence small-angle scattering measurements are useful methods to investigate the in-plane structure and its correlation of layered systems. Although these measurements give information on complementary and overlapping length scale, the different characteristics between them need to be taken into account when performed. In this study, the difference in the accessible length scale of the in-plane structure, which is one of the most important characteristics, was discussed using an Fe/Si multilayer together with simulations based on the distorted wave Born approximation.

  7. Correlations of properties and structures at different length scales of hydro- and organo-gels based on N-alkyl-(R)-12-hydroxyoctadecylammonium chlorides.

    Science.gov (United States)

    Mallia, V Ajay; Terech, Pierre; Weiss, Richard G

    2011-11-03

    The self-assembly and gelating ability of a set of N-alkyl-(R)-12-hydroxyoctadecylammonium chlorides (NCl-n, where n = 0-6, 18 is the length of the alkyl chain on nitrogen) are described. Several are found to be ambidextrous (gelating both water and a variety of organic liquids) and very efficient (needing less than ca. 0.5 wt % at room temperature). Structure-property correlations at different distance scales of the NCl-n in their hydro- and organo-gels and neat, solid states have been made using X-ray diffraction, neutron scattering, thermal, optical, cryo-SEM and rheological techniques. The self-assembled fibrillar networks consist of spherulitic objects with fibers whose diameters and degrees of twisting differ in the hydro- and organo-gels. Increasing n (and, thus, the molecular length) increases the width of the fibers in their hydrogels; an irregular, less pronounced trend between n and fiber width is observed in the corresponding toluene gels. Time-dependent, small angle neutron scattering data for the isothermal sol-to-gel transformation of sols of NCl-18/toluene to their gels, treated according to Avrami theory, indicate heterogeneous nucleation involving rodlike growth. Rheological studies of gels of NCl-3 in water and toluene confirm their viscoelastic nature and show that the hydrogel is mechanically stronger than the toluene gel. Models for the different molecular packing arrangements within the fibrillar gel networks of the hydro- and organogels have been inferred from X-ray diffraction. The variations in the fibrillar networks provide a comprehensive picture and detailed insights into why seemingly very similar NCl-n behave very differently during their self-assembly processes in water and organic liquids. It is shown that the NCl-n provide a versatile platform for interrogating fundamental questions regarding the links between molecular structure and one-dimensional self-aggregation, leading to gelation.

  8. Chain length dependence of the helix orientation in Langmuir-Blodgett monolayers of alpha-helical diblock copolypeptides

    NARCIS (Netherlands)

    Nguyen, Le-Thu T.; Ardana, Aditya; Vorenkamp, Eltjo J.; ten Brinke, Gerrit; Schouten, Arend J.

    2010-01-01

    The effect of chain length on the helix orientation of alpha-helical diblock copolypeptides in Langmuir and Langmuir-Blodgett monolayers is reported for the first time. Amphiphilic diblock copolypeptides (PLGA-b-PMLGSLGs) of poly(alpha-L-glutamic acid) (PLGA) and

  9. Concentration dependence of alpha-synuclein fibril length assessed by quantitative atomic force microscopy and statistical-mechanical theory

    NARCIS (Netherlands)

    van Raaij, Martijn E; van Gestel, Jeroen; Segers-Nolten, Ine M J; de Leeuw, Simon W; Subramaniam, Vinod

    2008-01-01

    The initial concentration of monomeric amyloidogenic proteins is a crucial factor in the in vitro formation of amyloid fibrils. We use quantitative atomic force microscopy to study the effect of the initial concentration of human alpha-synuclein on the mean length of mature alpha-synuclein fibrils,

  10. Establishing a clinically relevant cutoff to the Dependency Scale from the dimensional clinical personality inventory.

    Science.gov (United States)

    Carvalho, Lucas de F; Pianowski, Giselle; Filho, Nelson H

    2017-05-01

    The Clinical Dimensional Personality Inventory (IDCP) is a 163-item self-report tool developed for the assessment of 12 dimensions of personality pathology. One of the scales comprising the instrument-the Dependency scale-is intended to provide psychometric information on traits closely related to the Dependent Personality Disorder (DPD). In the present study, we used both Item Response Theory modeling and Receiver Operating Characteristic curve analysis to establishing a clinically meaningful cutoff for the IDCP Dependency Scale. Participants were 2.481 adults, comprised by outpatients diagnosed with DPD, outpatients diagnosed with other PDs, and adults from the general population. The Wright's item map graphing technique revealed that outpatients were located at the very high levels in the latent scale continuum of the Dependency Scale, with a very large effect size for the mean difference between patients and non-patients. The ROC curve analysis supported a cutoff at 2.3 points in the Dependency Scale, which yielded 0.86 of sensitivity and 0.79 of specificity. Findings from the present investigation suggest the IDCP Dependency Scale is useful as a screening tool of the core features of the DPD. We address potential clinical applications for the instrument, and discuss limitations from the present study. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  11. The care dependency scale for measuring basic human needs: an international comparison.

    Science.gov (United States)

    Dijkstra, Ate; Yönt, Gülendam Hakverdioğlu; Korhan, Esra Akin; Muszalik, Marta; Kędziora-Kornatowska, Kornelia; Suzuki, Mizue

    2012-10-01

    To report a study conducted to compare the utility of the care dependency scale across four countries. The care dependency scale provides a framework for assessing the needs of institutionalized patients for nursing care. Henderson's components of nursing care have been used to specify the variable aspects of the concept of care dependency and to develop the care dependency scale items. The study used a cross-cultural survey design. Patients were recruited from four different countries: Japan, The Netherlands, Poland and Turkey. In each of the participating countries, basic human needs were assessed by nurses using a translated version of the original Dutch care dependency scale. Psychometric properties in terms of reliability and validity of the care dependency scale have been assessed using Cronbach's alpha, Guttman's lambda-2, inter-item correlation and principal components analysis. Data were collected in 2008 and 2009. High internal consistency values were demonstrated. Principal component analysis confirmed the one-factor model reported in earlier studies. Outcomes confirm Henderson's idea that human needs are fundamental appearing in every patient-nurse relationship, independent of the patient's age, the type of care setting and/or cultural background. The psychometric characteristics of the care dependency scale make this instrument very useful for comparative research across countries. © 2012 Blackwell Publishing Ltd.

  12. Effect of polydispersity on the structure factor of a melt of binary multiblock copolymers with a two-length-scale macromolecular architecture

    NARCIS (Netherlands)

    Kuchanov, S.; Zharnikov, T.; Brinke, G. ten

    2011-01-01

    A theoretical study on the effect of polydispersity of two-length-scale binary multiblock copolymers on the shape of the structure factor is presented. A bifurcation diagram is constructed showing the partition of the parameter space into domains differing in the way in which the homogeneous melt

  13. On the validity of 2D critical taper theory in 3D wedges: defining a lateral deformation length scale

    Science.gov (United States)

    Leever, Karen; Oncken, Onno; Thorden Haug, Øystein

    2015-04-01

    For 2D critical taper theory to be applicable to 3D natural cases, cylindric deformation is a requirement. The assumption of cylindricity is violated in case of localized perturbations (subducting seamount, localized sedimentation) or due to a lateral change in decollement strength or depth. In natural accretionary wedges and fold-and-thrust belts, along strike changes may occur in a variety of ways: geometrical (due to a protruding indenter or a change in decollement depth), through a lateral change in basal friction (leading to laterally different tapers), or through a change in surface slope (by strongly localized fan sedimentation on accretionary wedges). Recent numerical modelling results (Ruh et al., 2013) have shown that lateral coupling preferentially occurs for relatively small perturbations, i.e. the horizontal shear stress caused by the perturbation is supported by the system. Lateral linking of the wedge in front of a protruding indenter to the wedge in front of the trailing edge of the back stop leads to curved thrust fronts and importantly it has been noted that even outside the curved zone, where the wedge front is again parallel to the direction of tectonic transport, the lateral effect is still evident: both tapers are different from the analytical prediction. We present results from a 3D analogue modelling parameter study to investigate this behavior more quantitatively, with the objective of empirically finding a lateral length scale of deformation in brittle contractional wedges. For a given wedge strength (angle of internal friction), we infer this to be a function of the size (width) of the perturbation and its magnitude (difference in basal friction). To this end we run different series of models in which we systematically vary the width and/or magnitude of a local perturbation. In the first series, the width of a zone of high basal friction is varied, in the second series we vary the width of an indenter and in the third series

  14. 'Length'at Length

    Indian Academy of Sciences (India)

    Admin

    He was interested to know how `large' is the set of numbers x for which the series is convergent. Here large refers to its length. But his set is not in the class ♢. Here is another problem discussed by Borel. Consider .... have an infinite collection of pairs of new shoes and want to choose one shoe from each pair. We have an ...

  15. Scale dependent controls of stream water temperatures - interaction of advective and diffusive energy fluxes

    Science.gov (United States)

    Schuetz, Tobias; Weiler, Markus

    2017-04-01

    Diurnal stream water temperature amplitudes (WTA) have a large impact on local ecohydrological conditions, e.g. aquatic habitat quality or biogeochemical cycling. Depending on discharge, streambed geomorphology, connectivity to the groundwater, hyporheic exchange flow and other local factors such as shading and climate conditions observable WTAs vary strongly from up- to downstream and can locally even exceed seasonal temperature variations. The main process which is responsible for the local expression of WTA is the energy balance which can be either dominated by advective energy fluxes (e. g. discharge and upwelling groundwater) or by diffusive energy fluxes (e. g. radiation, latent and sensible heat fluxes, heat exchange with the streambed). In recent years research has mainly focused on improving our knowledge how groundwater-surface water interaction, hyporheic exchange and shading processes influence locally observable WTA in smaller streams, while for larger streams or rivers WTA might even be non-observable throughout the year. Within this study we analyze the scaling behavior of advective and diffusive energy fluxes from small to large streams to better understand on which scales and under which conditions WTA might be dominated either by advective or diffusive energy fluxes and how groundwater - surface water interaction influences this relationship. For this purpose, we carried out a synthetic model study. Using published hydraulic geometry relations for different types of rivers, we apply a conceptual energy balance- and mixing model, which includes GW-SW interaction, discharges from 100 l/s up to 50 m3/s on length scales from 100 m up to 50 km. Simulated boundary conditions were constant discharges at the upstream boundary and constant and uniformly distributed exchange fluxes to the groundwater. Upstream water temperatures were 15 °C (WTA of 5 °C), while groundwater temperature was assumed to be cooler than the stream with 9°C. Net diffusive energy

  16. Movement reveals scale dependence in habitat selection of a large ungulate

    Science.gov (United States)

    Northrup, Joseph; Anderson, Charles R.; Hooten, Mevin B.; Wittemyer, George

    2016-01-01

    Ecological processes operate across temporal and spatial scales. Anthropogenic disturbances impact these processes, but examinations of scale dependence in impacts are infrequent. Such examinations can provide important insight to wildlife–human interactions and guide management efforts to reduce impacts. We assessed spatiotemporal scale dependence in habitat selection of mule deer (Odocoileus hemionus) in the Piceance Basin of Colorado, USA, an area of ongoing natural gas development. We employed a newly developed animal movement method to assess habitat selection across scales defined using animal-centric spatiotemporal definitions ranging from the local (defined from five hour movements) to the broad (defined from weekly movements). We extended our analysis to examine variation in scale dependence between night and day and assess functional responses in habitat selection patterns relative to the density of anthropogenic features. Mule deer displayed scale invariance in the direction of their response to energy development features, avoiding well pads and the areas closest to roads at all scales, though with increasing strength of avoidance at coarser scales. Deer displayed scale-dependent responses to most other habitat features, including land cover type and habitat edges. Selection differed between night and day at the finest scales, but homogenized as scale increased. Deer displayed functional responses to development, with deer inhabiting the least developed ranges more strongly avoiding development relative to those with more development in their ranges. Energy development was a primary driver of habitat selection patterns in mule deer, structuring their behaviors across all scales examined. Stronger avoidance at coarser scales suggests that deer behaviorally mediated their interaction with development, but only to a degree. At higher development densities than seen in this area, such mediation may not be possible and thus maintenance of sufficient

  17. Nuclear size and rapidity dependence of the saturation scale from QCD evolution and experimental data

    International Nuclear Information System (INIS)

    Albacete, J.L.; Armesto, N.; Guilherme Milhano, J.; Salgado, C.A.; Wiedemann, U.A.

    2005-01-01

    The solutions of the Balitsky-Kovchegov evolution equations are studied numerically and compared with known analytical estimations. The rapidity and nuclear size dependences of the saturation scale are obtained for the cases of fixed and running coupling constant. These same dependences are studied in experimental data, on lepton-nucleus, deuteron-nucleus and nucleus-nucleus collisions, through geometric scaling and compared with the theoretical calculations. (orig.)

  18. Scale-dependent three-dimensional charged black holes in linear and non-linear electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rincon, Angel; Koch, Benjamin [Pontificia Universidad Catolica de Chile, Instituto de Fisica, Santiago (Chile); Contreras, Ernesto; Bargueno, Pedro; Hernandez-Arboleda, Alejandro [Universidad de los Andes, Departamento de Fisica, Bogota, Distrito Capital (Colombia); Panotopoulos, Grigorios [Universidade de Lisboa, CENTRA, Instituto Superior Tecnico, Lisboa (Portugal)

    2017-07-15

    In the present work we study the scale dependence at the level of the effective action of charged black holes in Einstein-Maxwell as well as in Einstein-power-Maxwell theories in (2 + 1)-dimensional spacetimes without a cosmological constant. We allow for scale dependence of the gravitational and electromagnetic couplings, and we solve the corresponding generalized field equations imposing the null energy condition. Certain properties, such as horizon structure and thermodynamics, are discussed in detail. (orig.)

  19. Non-equilibrium Green's function analysis of cross section and channel length dependence of phonon scattering and its impact on the performance of Si nanowire field effect transistors

    Science.gov (United States)

    Aldegunde, M.; Martinez, A.; Asenov, A.

    2011-11-01

    In this paper, we study the effect of phonon scattering in silicon nanowire field effect transistors (NWFET) using a Non-equilibrium Green's function formalism in the effective mass approximation. The effect of electron-phonon scattering on the current voltage characteristics at high and low drain bias is investigated in detail. A wide range of cross-sections (from 2.2 × 2.2 to 6.2 × 6.2 nm2) and channel lengths (from 6 to 40 nm) are considered. The impact of phonon scattering on the electron current in different regions of the device characteristics is studied. Simulations including scattering in the whole transistor are compared with corresponding simulations in which scattering is only in the channel. Phonon limited mobility dependence on the NWFET cross-section and channel length is studied. The ballisticity coefficient, as a function of the channel length and gate voltage, is also computed for various channel cross-sections and lengths at high drain bias. The paper demonstrates that tunneling plays an important role in understanding the effect of phonon scattering at short channel lengths.

  20. Effect of artificial length scales in large eddy simulation of a neutral atmospheric boundary layer flow: A simple solution to log-layer mismatch

    Science.gov (United States)

    Chatterjee, Tanmoy; Peet, Yulia T.

    2017-07-01

    A large eddy simulation (LES) methodology coupled with near-wall modeling has been implemented in the current study for high Re neutral atmospheric boundary layer flows using an exponentially accurate spectral element method in an open-source research code Nek 5000. The effect of artificial length scales due to subgrid scale (SGS) and near wall modeling (NWM) on the scaling laws and structure of the inner and outer layer eddies is studied using varying SGS and NWM parameters in the spectral element framework. The study provides an understanding of the various length scales and dynamics of the eddies affected by the LES model and also the fundamental physics behind the inner and outer layer eddies which are responsible for the correct behavior of the mean statistics in accordance with the definition of equilibrium layers by Townsend. An economical and accurate LES model based on capturing the near wall coherent eddies has been designed, which is successful in eliminating the artificial length scale effects like the log-layer mismatch or the secondary peak generation in the streamwise variance.

  1. New parametrization for the scale dependent growth function in general relativity

    International Nuclear Information System (INIS)

    Dent, James B.; Dutta, Sourish; Perivolaropoulos, Leandros

    2009-01-01

    We study the scale-dependent evolution of the growth function δ(a,k) of cosmological perturbations in dark energy models based on general relativity. This scale dependence is more prominent on cosmological scales of 100h -1 Mpc or larger. We derive a new scale-dependent parametrization which generalizes the well-known Newtonian approximation result f 0 (a)≡(dlnδ 0 /dlna)=Ω(a) γ (γ=(6/11) for ΛCDM) which is a good approximation on scales less than 50h -1 Mpc. Our generalized parametrization is of the form f(a)=(f 0 (a)/1+ξ(a,k)), where ξ(a,k)=(3H 0 2 Ω 0m )/(ak 2 ). We demonstrate that this parametrization fits the exact result of a full general relativistic evaluation of the growth function up to horizon scales for both ΛCDM and dynamical dark energy. In contrast, the scale independent parametrization does not provide a good fit on scales beyond 5% of the horizon scale (k≅0.01h -1 Mpc).

  2. Current increment of tunnel field-effect transistor using InGaAs nanowire/Si heterojunction by scaling of channel length

    OpenAIRE

    Tomioka, Katsuhiro; Fukui, Takashi

    2014-01-01

    We report on a fabrication of tunnel field-effect transistors using InGaAs nanowire/Si heterojunctions and the characterization of scaling of channel lengths. The devices consisted of single InGaAs nanowires with a diameter of 30 nm grown on p-type Si(111) substrates. The switch demonstrated steep subthreshold-slope (30 mV/decade) at drain-source voltage (V-DS) of 0.10 V. Also, pinch-off behavior appeared at moderately low VDS, below 0.10 V. Reducing the channel length of the transistors atta...

  3. Dynamics of an elastic sphere containing a thin creeping region and immersed in an acoustic region for similar viscous-elastic and acoustic time- and length-scales

    Science.gov (United States)

    Gat, Amir; Friedman, Yonathan

    2017-11-01

    The characteristic time of low-Reynolds number fluid-structure interaction scales linearly with the ratio of fluid viscosity to solid Young's modulus. For sufficiently large values of Young's modulus, both time- and length-scales of the viscous-elastic dynamics may be similar to acoustic time- and length-scales. However, the requirement of dominant viscous effects limits the validity of such regimes to micro-configurations. We here study the dynamics of an acoustic plane wave impinging on the surface of a layered sphere, immersed within an inviscid fluid, and composed of an inner elastic sphere, a creeping fluid layer and an external elastic shell. We focus on configurations with similar viscous-elastic and acoustic time- and length-scales, where the viscous-elastic speed of interaction between the creeping layer and the elastic regions is similar to the speed of sound. By expanding the linearized spherical Reynolds equation into the relevant spectral series solution for the hyperbolic elastic regions, a global stiffness matrix of the layered elastic sphere was obtained. This work relates viscous-elastic dynamics to acoustic scattering and may pave the way to the design of novel meta-materials with unique acoustic properties. ISF 818/13.

  4. Scale Dependence of the Effective Matrix Diffusion Coefficient : Evidence and Preliminary Interpretation

    International Nuclear Information System (INIS)

    H.H. Liu; Y. Zhang

    2006-01-01

    The exchange of solute mass (through molecular diffusion) between fluid in fractures and fluid in the rock matrix is called matrix diffusion. Owing to the orders-of-magnitude slower flow velocity in the matrix compared to fractures, matrix diffusion can significantly retard solute transport in fractured rock, and therefore is an important process for a variety of problems, including remediation of subsurface contamination and geological disposal of nuclear waste. The effective matrix diffusion coefficient (molecular diffusion coefficient in free water multiplied by matrix tortuosity) is an important parameter for describing matrix diffusion, and in many cases largely determines overall solute transport behavior. While matrix diffusion coefficient values measured from small rock samples in the laboratory are generally used for modeling field-scale solute transport in fractured rock (Boving and Grathwohl, 2001), several research groups recently have independently found that effective matrix diffusion coefficients much larger than laboratory measurements are needed to match field-scale tracer-test data (Neretnieks, 2002; Becker and Shapiro, 2000; Shapiro, 2001; Liu et al., 2003,2004a). In addition to the observed enhancement, Liu et al. (2004b), based on a relatively small number of field-test results, reported that the effective matrix diffusion coefficient might be scale dependent, and, like permeability and dispersivity, it seems to increases with test scale. This scale-dependence has important implications for large-scale solute transport in fractured rock. Although a number of mechanisms have been proposed to explain the enhancement of the effective matrix diffusion coefficient, the potential scale dependence and its mechanisms are not fully investigated at this stage. The major objective of this study is to again demonstrate (based on more data published in the literature than those used in Liu et al. [2004b]) the potential scale dependence of the effective

  5. Effects of magnetic order on the superconducting length scales and critical fields in single crystal ErNi2B2C

    DEFF Research Database (Denmark)

    Gammel, P.L.; Barber, B.P.; Ramirez, A.P.

    1999-01-01

    The flux line form factor in small angle neutron scattering and transport data determines the superconducting length scares and critical fields in single crystal ErNi2B2C. For H parallel to c, the coherence length xi increases and the penetration depth lambda decreases when crossing T-N = 6.0 K......, the Neel transition. The critical fields show corresponding anomalies near T-N. For H perpendicular to c, the fourfold modulation of the upper critical field H-c2 is strongly temperature dependent, changing sign near T-N, and can be modeled using the anisotropy of the sublattice magnetization....

  6. Utilizing Monte-Carlo radiation transport and spallation cross sections to estimate nuclide dependent scaling with altitude

    Science.gov (United States)

    Argento, D.; Reedy, R. C.; Stone, J.

    2010-12-01

    Cosmogenic Nuclides (CNs) are a critical new tool for geomorphology, allowing researchers to date Earth surface events and measure process rates [1]. Prior to CNs, many of these events and processes had no absolute method for measurement and relied entirely on relative methods [2]. Continued improvements in CN methods are necessary for expanding analytic capability in geomorphology. In the last two decades, significant progress has been made in refining these methods and reducing analytic uncertainties [1,3]. Calibration data and scaling methods are being developed to provide a self consistent platform for use in interpreting nuclide concentration values into geologic data [4]. However, nuclide dependent scaling has been difficult to address due to analytic uncertainty and sparseness in altitude transects. Artificial target experiments are underway, but these experiments take considerable time for nuclide buildup in lower altitudes. In this study, a Monte Carlo method radiation transport code, MCNPX, is used to model the galactic cosmic-ray radiation impinging on the upper atmosphere and track the resulting secondary particles through a model of the Earth’s atmosphere and lithosphere. To address the issue of nuclide dependent scaling, the neutron flux values determined by the MCNPX simulation are folded in with estimated cross-section values [5,6]. Preliminary calculations indicate that scaling of nuclide production potential in free air seems to be a function of both altitude and nuclide production pathway. At 0 g/cm2 (sea-level) all neutron spallation pathways have attenuation lengths within 1% of 130 g/cm2. However, the differences in attenuation length are exacerbated with increasing altitude. At 530 g/cm2 atmospheric height (~5,500 m), the apparent attenuation lengths for aggregate SiO2(n,x)10Be, aggregate SiO2(n,x)14C and K(n,x)36Cl become 149.5 g/cm2, 151 g/cm2 and 148 g/cm2 respectively. At 700 g/cm2 atmospheric height (~8,400m - close to the highest

  7. Dependence of Hydraulic Conductivity on Test Scale: Artifact or Something More?

    Science.gov (United States)

    Butler, J. J., Jr.

    2014-12-01

    Over the years, there have been frequent reports of a dependence of hydraulic conductivity (K) estimates on test volume (scale). This dependence is commonly demonstrated using results from laboratory permeameter tests and from slug and pumping tests. Typically, K estimates from pumping tests are reported to be considerably larger than those from slug tests, which, in turn, are considerably larger than those from permeameter tests. Despite the large body of evidence, a key question remains unresolved - is this relationship produced by methodological differences or a natural underlying scale dependence in K? The most effective means to resolve this question is to use a single technique that can be configured to span orders of magnitude in test scale. The constant-rate pumping test is just such a technique. In the first few minutes to tens of minutes of pumping, the affected volume is relatively small. In contrast, after days of pumping, this volume can be orders of magnitude larger. If there is an underlying scale dependence, it should be revealed by K estimates determined from different durations of pumping. We have been investigating this issue using pumping tests in unconsolidated aquifers in central and western Kansas. In western Kansas, irrigation wells are pumped nearly continuously for the entire growing season. If nearby observation wells are available, we can use this near-continuous pumping as a long-duration, albeit imperfectly controlled, pumping test to increase the scale of the investigation. An initial assessment of these formal and ad-hoc pumping tests has found no evidence of a scale dependence in K; these tests are typically characterized by homogeneous aquifer behavior at small to moderate times of pumping after which boundary effects become dominant. Thus, if there is an underlying scale dependence, it is below the scale of these observations, which would have to be considered rather serendipitous. We can assess the relationship at smaller scales

  8. Induction of oral tolerance with micro-doses of ovomucoid depends on the length of the feeding period

    DEFF Research Database (Denmark)

    Kjær, Tanja; Frøkiær, Hanne

    2002-01-01

    Oral administration of antigen induces antigen-specific immunologic tolerance, which is known to be dose-dependent. We studied the influence of continuous oral administration of nanogram and microgram doses of antigen on oral tolerance induction. Mice were continuously exposed to varying doses (1...... ng-1 mg/day) of ovomucoid (OM) for a minimum of 30 days and a maximum of 100 days. It was possible to induce oral tolerance measured as reduced proliferation and antibody production (immunoglobulin (Ig)G(1), IgG(2a), and total Igs) when mice were fed 1 mg of OM/day for 40 or 50 days....... It was not possible to induce oral tolerance with daily doses of antigen of 10 mug or less. Feeding of 100 mug OM/day for 40 and 50 days and 1 mg OM/day for 30 days generated tolerization of Th2-dependent responses, but retained an intact response of Th1-dependent antibodies, whereas feeding of 1 mg OM/day for 40...

  9. Investigations of the energy and angular dependence of ultra-short radiation lengths in Si, Ge and W single crystals

    CERN Multimedia

    Very recently, experiments NA33 and WA81 have shown that pair production by energetic photons incident along crystalline directions is strongly enhanced as compared to the Bethe-Heitler value for amorphous targets. The enhanced pair production sets in at around 40 GeV in Ge crystals and rises almost linearly with photon energy up to a calculated maximum enhancement of around thirty. In Si, this maximum is expected to be nearly two orders of magnitude above the Bethe-Heitler value.\\\\ For GeV electrons/positrons incident along crystal axes, the radiation energy loss also shows a very large enhancement of approximately two orders of magnitude. In a 0.4 mm W crystal, a 100 GeV electron is expected to emit on average 70% of its total energy.\\\\ The combination of these two dramatic enhancements means that the electromagnetic shower develops much faster around crystalline directions, corresponding to ultrashort radiation lengths.\\\\ The aim of this experiment is to investigate the shower development in ...

  10. Development of Lab-to-Fab Production Equipment Across Several Length Scales for Printed Energy Technologies, Including Solar Cells

    DEFF Research Database (Denmark)

    Hösel, Markus; Dam, Henrik Friis; Krebs, Frederik C

    2015-01-01

    We describe and review how the scaling of printed energy technologies not only requires scaling of the input materials but also the machinery used in the processes. The general consensus that ultrafast processing of technologies with large energy capacity can only be realized using roll-to-roll m......We describe and review how the scaling of printed energy technologies not only requires scaling of the input materials but also the machinery used in the processes. The general consensus that ultrafast processing of technologies with large energy capacity can only be realized using roll...... the lower end of the industrial scale. The machinery bridges the gap through firstly achieving improved ink efficiency without surface contact, followed by better ink efficiency at higher speeds, and finally large-area processing at high speed with very high ink efficiency....

  11. Testing the Scale Dependence of the Scale Factor $\\sigma_{eff}$ in Double Dijet Production at the LHC

    CERN Document Server

    Domdey, Svend; Wiedemann, Urs Achim

    2010-01-01

    The scale factor σ eff is the effective cross section used to characterize the measured rate of inclusive double dijet production in high energy hadron collisions. It is sensitive to the two-parton distributions in the hadronic projectile. In principle, the scale factor depends on the center of mass energy and on the minimal transverse energy of the jets contributing to the double dijet cross section. Here, we point out that proton-proton collisions at the LHC will provide for the first time experimental access to these scale dependences in a logarithmically wide, nominally perturbative kinematic range of minimal transverse energy between 10 GeV and 100 GeV. This constrains the dependence of two-parton distribution functions on parton momentum fractions and parton localization in impact parameter space. Novel information is to be expected about the transverse growth of hadronic distribution functions in the range of semi-hard Bjorken x (0.001 < x < 0.1) and high resolution Q^2. We discuss to what exten...

  12. Colour Determination and Change of Sensory Properties of Mayonnaise with Different Contents of Oil Depending on Length of Storage

    Directory of Open Access Journals (Sweden)

    Višnja M. SIKIMIĆ

    2010-01-01

    Full Text Available This paper studies the stability of three types of mayonnaise (with 75 %, 50 % and 30 % of edible refined sunflower oil and other additives by measuring colour on photoelectric tristimulus colorimeter “MOM-colour 100“, showing the results in CIE (Y(%, l (nm and Č (% and CIE L ´ a ´ b system immediately after preparation, after 90 and 180 days of warehousing, at temperature of +5°C. In parallel, sensory analysis was conducted by means of the analytical point system when a group of experienced tasters evaluated the appearance, colour, fragrance and taste, during the storage lasting up to 180 days. It was established that average estimates for the appearance, colour and both, statistically do not depend significantly on the contents of mayonnaise and statistically very much depend on the time of storage. The interaction of contents of mayonnaise and time of storage statistically significantly influences the average estimate of the appearance and to all sensory properties.

  13. Rough surface electrical contact resistance considering scale dependent properties and quantum effects

    International Nuclear Information System (INIS)

    Jackson, Robert L.; Crandall, Erika R.; Bozack, Michael J.

    2015-01-01

    The objective of this work is to evaluate the effect of scale dependent mechanical and electrical properties on electrical contact resistance (ECR) between rough surfaces. This work attempts to build on existing ECR models that neglect potentially important quantum- and size-dependent contact and electrical conduction mechanisms present due to the asperity sizes on typical surfaces. The electrical conductance at small scales can quantize or show a stepping trend as the contact area is varied in the range of the free electron Fermi wavelength squared. This work then evaluates if these effects remain important for the interface between rough surfaces, which may include many small scale contacts of varying sizes. The results suggest that these effects may be significant in some cases, while insignificant for others. It depends on the load and the multiscale structure of the surface roughness

  14. Burnup dependent core neutronic calculations for research and training reactors via SCALE4.4

    International Nuclear Information System (INIS)

    Tombakoglu, M.; Cecen, Y.

    2001-01-01

    In this work, the full core modelling is performed to improve neutronic analyses capability for nuclear research reactors using SCALE4.4 code system. KENOV.a module of SCALE4.4 code system is utilized for full core neutronic analysis. The ORIGEN-S module is coupled with the KENOV.a module to perform burnup dependent neutronic analyses. Results of neutronic calculations for 1 st cycle of Cekmece TR-2 research reactor are presented. In particular, coupling of KENOV.a and ORIGEN-S modules of SCALE4.4 is discussed. The preliminary results of 2-D burnup dependent neutronic calculations are also given. These results are extended to burnup dependent core calculations of TRIGA Mark-II research reactors. The code system developed here is similar to the code system that couples MCNP and ORIGEN2.(author)

  15. On the Soft Limit of the Large Scale Structure Power Spectrum: UV Dependence

    CERN Document Server

    Garny, Mathias; Porto, Rafael A; Sagunski, Laura

    2015-01-01

    We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the soft limit. The resulting equation encodes the coupling to ultraviolet (UV) modes in two time-dependent coefficients, which may be obtained from response functions to (anisotropic) parameters, such as spatial curvature, in a modified cosmology. We argue that both depend weakly on fluctuations deep in the UV. As a byproduct, this implies that the renormalized leading order coefficient(s) in the effective field theory (EFT) of large scale structures receive most of their contribution from modes close to the non-linear scale. Consequently, the UV dependence found in explicit computations within standard perturbation theory stems mostly from counter-term(s). We confront a simplified version of our non-perturbative equation against existent numerical simulations, and find good agr...

  16. Ileal transposition surgery produces ileal length-dependent changes in food intake, body weight, gut hormones and glucose metabolism in rats.

    Science.gov (United States)

    Ramzy, A R; Nausheen, S; Chelikani, P K

    2014-03-01

    Enhanced stimulation of the lower gut is hypothesized to play a key role in the weight loss and resolution of diabetes following bariatric surgeries. Ileal transposition (IT) permits study of the effects of direct lower gut stimulation on body weight, glucose homeostasis and other metabolic adaptations without the confounds of gastric restriction or foregut exclusion. However, the underlying mechanisms and the length of the ileum sufficient to produce metabolic benefits following IT surgery remain largely unknown. To determine the effects of transposing varying lengths of the ileum to upper jejunum on food intake, body weight, glucose tolerance and lower gut hormones, and the expression of key markers of glucose and lipid metabolism in skeletal muscle and adipose tissue in rats. Adult male Sprague-Dawley rats (n=9/group) were subjected to IT surgery with translocation of 5, 10 or 20 cm of the ileal segment to proximal jejunum or sham manipulations. Daily food intake and body weight were recorded, and an intraperitoneal glucose tolerance test was performed. Blood samples were assayed for hormones and tissue samples for mRNA (RT-qPCR) and/or protein abundance (immunoblotting) of regulatory metabolic markers. We demonstrate that IT surgery exerts ileal length-dependent effects on multiple parameters including: (1) decreased food intake and weight gain, (2) improved glucose tolerance, (3) increased tissue expression and plasma concentrations of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), and decreased leptin concentrations and (4) upregulation of key markers of glucose metabolism (glucose transporter-4 (GLUT-4), insulin receptor substrate 1 (IRS-1), adenosine monophosphate-activated protein kinase (AMPK), hexokinase (HK) and phosphofructokinase (PFK)) together with a downregulation of lipogenic markers (fatty acid synthase (FAS)) in muscle and adipose tissue. Together, our data demonstrate that the reduction in food intake and weight gain, increase in lower

  17. A scale-dependent bias on linear scales: the case for H I intensity mapping at z = 1

    Science.gov (United States)

    Pénin, Aurélie; Umeh, Obinna; Santos, Mario G.

    2018-02-01

    Neutral hydrogen (H I) will soon be the dark matter tracer observed over the largest volumes of Universe, thanks to the 21-cm intensity mapping technique. To unveil cosmological information, it is indispensable to understand the H I distribution with respect to dark matter. Using a full one-loop derivation of the power spectrum of H I, we show that higher order corrections change the amplitude and shape of the power spectrum on typical cosmological (linear) scales. These effects go beyond the expected dark matter non-linear corrections and include non-linearities in the way the H I signal traces dark matter. We show that, on linear scales at z = 1, the H I bias drops by up to 15 per cent in both real and redshift space, which results in underpredicting the mass of the haloes in which H I lies. Non-linear corrections give rise to a significant scale dependence when redshift space distortions arise, in particular on the scale range of the baryonic acoustic oscillations (BAOs). There is a factor of 5 difference between the linear and full H I power spectra over the whole BAO scale range, which modifies the ratios between the peaks. This effect will also be seen in other types of survey and it will be essential to take it into account in future experiments in order to match the expectations of precision cosmology.

  18. Simulations of micro-bending of thin foils using a scale dependent crystal plasticity model

    DEFF Research Database (Denmark)

    Kuroda, Mitsutoshi; Tvergaard, Viggo; Ohashi, T.

    2007-01-01

    In this paper, we perform crystal plasticity analyses of micro-bending of thin f.c.c. metal foils having thicknesses ranging from 10 to 50 mu m. The scale dependent crystal plasticity model used here is a viscoplastic finite strain version of the model proposed by Ohashi (2005 Int. J. Plast. 21...... a Bailey-Hirsch type relation. The computational results are compared with the experimental results for Ni foils, reported in Stolken and Evans (1998 Acta Mater. 46 5109-15). The validity of the current model and the direction of future development of the 'physically-based' scale dependent crystal...

  19. Scale-dependent portfolio effects explain growth inflation and volatility reduction in landscape demography.

    Science.gov (United States)

    Hui, Cang; Fox, Gordon A; Gurevitch, Jessica

    2017-11-21

    Population demography is central to fundamental ecology and for predicting range shifts, decline of threatened species, and spread of invasive organisms. There is a mismatch between most demographic work, carried out on few populations and at local scales, and the need to predict dynamics at landscape and regional scales. Inspired by concepts from landscape ecology and Markowitz's portfolio theory, we develop a landscape portfolio platform to quantify and predict the behavior of multiple populations, scaling up the expectation and variance of the dynamics of an ensemble of populations. We illustrate this framework using a 35-y time series on gypsy moth populations. We demonstrate the demography accumulation curve in which the collective growth of the ensemble depends on the number of local populations included, highlighting a minimum but adequate number of populations for both regional-scale persistence and cross-scale inference. The attainable set of landscape portfolios further suggests tools for regional population management for both threatened and invasive species.

  20. The full-length E1-circumflexE4 protein of human papillomavirus type 18 modulates differentiation-dependent viral DNA amplification and late gene expression

    International Nuclear Information System (INIS)

    Wilson, Regina; Ryan, Gordon B.; Knight, Gillian L.; Laimins, Laimonis A.; Roberts, Sally

    2007-01-01

    Activation of the productive phase of the human papillomavirus (HPV) life cycle in differentiated keratinocytes is coincident with high-level expression of E1-circumflexE4 protein. To determine the role of E1-circumflexE4 in the HPV replication cycle, we constructed HPV18 mutant genomes in which expression of the full-length E1-circumflexE4 protein was abrogated. Undifferentiated keratinocytes containing mutant genomes showed enhanced proliferation when compared to cells containing wildtype genomes, but there were no differences in maintenance of viral episomes. Following differentiation, cells with mutant genomes exhibited reduced levels of viral DNA amplification and late gene expression, compared to wildtype genome-containing cells. This indicates that HPV18 E1-circumflexE4 plays an important role in regulating HPV late functions, and it may also function in the early phase of the replication cycle. Our finding that full-length HPV18 E1-circumflexE4 protein plays a significant role in promoting viral genome amplification concurs with a similar report with HPV31, but is in contrast to an HPV11 study where viral DNA amplification was not dependent on full-length E1-circumflexE4 expression, and to HPV16 where only C-terminal truncations in E1-circumflexE4 abrogated vegetative genome replication. This suggests that type-specific differences exist between various E1-circumflexE4 proteins

  1. Large-scale collection and annotation of full-length enriched cDNAs from a model halophyte, Thellungiella halophila

    Directory of Open Access Journals (Sweden)

    Seki Motoaki

    2008-11-01

    Full Text Available Abstract Background Thellungiella halophila (also known as Thellungiella salsuginea is a model halophyte with a small plant size, short life cycle, and small genome. It easily undergoes genetic transformation by the floral dipping method used with its close relative, Arabidopsis thaliana. Thellungiella genes exhibit high sequence identity (approximately 90% at the cDNA level with Arabidopsis genes. Furthermore, Thellungiella not only shows tolerance to extreme salinity stress, but also to chilling, freezing, and ozone stress, supporting the use of Thellungiella as a good genomic resource in studies of abiotic stress tolerance. Results We constructed a full-length enriched Thellungiella (Shan Dong ecotype cDNA library from various tissues and whole plants subjected to environmental stresses, including high salinity, chilling, freezing, and abscisic acid treatment. We randomly selected about 20 000 clones and sequenced them from both ends to obtain a total of 35 171 sequences. CAP3 software was used to assemble the sequences and cluster them into 9569 nonredundant cDNA groups. We named these cDNAs "RTFL" (RIKEN Thellungiella Full-Length cDNAs. Information on functional domains and Gene Ontology (GO terms for the RTFL cDNAs were obtained using InterPro. The 8289 genes assigned to InterPro IDs were classified according to the GO terms using Plant GO Slim. Categorical comparison between the whole Arabidopsis genome and Thellungiella genes showing low identity to Arabidopsis genes revealed that the population of Thellungiella transport genes is approximately 1.5 times the size of the corresponding Arabidopsis genes. This suggests that these genes regulate a unique ion transportation system in Thellungiella. Conclusion As the number of Thellungiella halophila (Thellungiella salsuginea expressed sequence tags (ESTs was 9388 in July 2008, the number of ESTs has increased to approximately four times the original value as a result of this effort. Our

  2. Gap length distributions by PEPR

    International Nuclear Information System (INIS)

    Warszawer, T.N.

    1980-01-01

    Conditions guaranteeing exponential gap length distributions are formulated and discussed. Exponential gap length distributions of bubble chamber tracks first obtained on a CRT device are presented. Distributions of resulting average gap lengths and their velocity dependence are discussed. (orig.)

  3. Criterion Noise in Ratings-Based Recognition: Evidence from the Effects of Response Scale Length on Recognition Accuracy

    Science.gov (United States)

    Benjamin, Aaron S.; Tullis, Jonathan G.; Lee, Ji Hae

    2013-01-01

    Rating scales are a standard measurement tool in psychological research. However, research has suggested that the cognitive burden involved in maintaining the criteria used to parcel subjective evidence into ratings introduces "decision noise" and affects estimates of performance in the underlying task. There has been debate over whether…

  4. Scale-dependent seasonal pool habitat use by sympatric Wild Brook Trout and Brown Trout populations

    Science.gov (United States)

    Davis, Lori A.; Wagner, Tyler

    2016-01-01

    Sympatric populations of native Brook Trout Salvelinus fontinalis and naturalized Brown Trout Salmo truttaexist throughout the eastern USA. An understanding of habitat use by sympatric populations is of importance for fisheries management agencies because of the close association between habitat and population dynamics. Moreover, habitat use by stream-dwelling salmonids may be further complicated by several factors, including the potential for fish to display scale-dependent habitat use. Discrete-choice models were used to (1) evaluate fall and early winter daytime habitat use by sympatric Brook Trout and Brown Trout populations based on available residual pool habitat within a stream network and (2) assess the sensitivity of inferred habitat use to changes in the spatial scale of the assumed available habitat. Trout exhibited an overall preference for pool habitats over nonpool habitats; however, the use of pools was nonlinear over time. Brook Trout displayed a greater preference for deep residual pool habitats than for shallow pool and nonpool habitats, whereas Brown Trout selected for all pool habitat categories similarly. Habitat use by both species was found to be scale dependent. At the smallest spatial scale (50 m), habitat use was primarily related to the time of year and fish weight. However, at larger spatial scales (250 and 450 m), habitat use varied over time according to the study stream in which a fish was located. Scale-dependent relationships in seasonal habitat use by Brook Trout and Brown Trout highlight the importance of considering scale when attempting to make inferences about habitat use; fisheries managers may want to consider identifying the appropriate spatial scale when devising actions to restore and protect Brook Trout populations and their habitats.

  5. The scaling of stress distribution under small scale yielding by T-scaling method and application to prediction of the temperature dependence on fracture toughness

    International Nuclear Information System (INIS)

    Ishihara, Kenichi; Hamada, Takeshi; Meshii, Toshiyuki

    2017-01-01

    In this paper, a new method for scaling the crack tip stress distribution under small scale yielding condition was proposed and named as T-scaling method. This method enables to identify the different stress distributions for materials with different tensile properties but identical load in terms of K or J. Then by assuming that the temperature dependence of a material is represented as the stress-strain relationship temperature dependence, a method to predict the fracture load at an arbitrary temperature from the already known fracture load at a reference temperature was proposed. This method combined the T-scaling method and the knowledge “fracture stress for slip induced cleavage fracture is temperature independent.” Once the fracture load is predicted, fracture toughness J c at the temperature under consideration can be evaluated by running elastic-plastic finite element analysis. Finally, the above-mentioned framework to predict the J c temperature dependency of a material in the ductile-to-brittle temperature distribution was validated for 0.55% carbon steel JIS S55C. The proposed framework seems to have a possibility to solve the problem the master curve is facing in the relatively higher temperature region, by requiring only tensile tests. (author)

  6. Bridging asymptotic independence and dependence in spatial exbtremes using Gaussian scale mixtures

    KAUST Repository

    Huser, Raphaël

    2017-06-23

    Gaussian scale mixtures are constructed as Gaussian processes with a random variance. They have non-Gaussian marginals and can exhibit asymptotic dependence unlike Gaussian processes, which are asymptotically independent except in the case of perfect dependence. In this paper, we study the extremal dependence properties of Gaussian scale mixtures and we unify and extend general results on their joint tail decay rates in both asymptotic dependence and independence cases. Motivated by the analysis of spatial extremes, we propose flexible yet parsimonious parametric copula models that smoothly interpolate from asymptotic dependence to independence and include the Gaussian dependence as a special case. We show how these new models can be fitted to high threshold exceedances using a censored likelihood approach, and we demonstrate that they provide valuable information about tail characteristics. In particular, by borrowing strength across locations, our parametric model-based approach can also be used to provide evidence for or against either asymptotic dependence class, hence complementing information given at an exploratory stage by the widely used nonparametric or parametric estimates of the χ and χ̄ coefficients. We demonstrate the capacity of our methodology by adequately capturing the extremal properties of wind speed data collected in the Pacific Northwest, US.

  7. Using Generalizability Theory to Examine the Dependability of Scores from the Learning Target Rating Scale

    Science.gov (United States)

    McLaughlin, Tara W.; Snyder, Patricia A.; Algina, James

    2017-01-01

    The Learning Target Rating Scale (LTRS) is a measure designed to evaluate the quality of teacher-developed learning targets for embedded instruction for early learning. In the present study, we examined the measurement dependability of LTRS scores by conducting a generalizability study (G-study). We used a partially nested, three-facet model to…

  8. Dependability and Treatment Sensitivity of Multi-Item Direct Behavior Rating Scales for Interpersonal Peer Conflict

    Science.gov (United States)

    Daniels, Brian; Volpe, Robert J.; Briesch, Amy M.; Gadow, Kenneth D.

    2017-01-01

    Direct behavior rating (DBR) represents a feasible method for monitoring student behavior in the classroom; however, limited work to date has focused on the use of multi-item scales. The purposes of the study were to examine the (a) dependability of data obtained from a multi-item DBR designed to assess peer conflict and (b) treatment sensitivity…

  9. Analysis of Queue-Length Dependent Vacations and P-Limited Service in BMAP/G/1/N Systems: Stationary Distributions and Optimal Control

    Directory of Open Access Journals (Sweden)

    A. D. Banik

    2013-01-01

    Full Text Available We consider a finite-buffer single server queueing system with queue-length dependent vacations where arrivals occur according to a batch Markovian arrival process (BMAP. The service discipline is P-limited service, also called E-limited with limit variation (ELV where the server serves until either the system is emptied or a randomly chosen limit of L customers has been served. Depending on the number of customers present in the system, the server will monitor his vacation times. Queue-length distributions at various epochs such as before, arrival, arbitrary and after, departure have been obtained. Several other service disciplines like Bernoulli scheduling, nonexhaustive service, and E-limited service can be treated as special cases of the P-limited service. Finally, the total expected cost function per unit time is considered to determine locally optimal values N* of N or a maximum limit L^* of L^ as the number of customers served during a service period at a minimum cost.

  10. Quasi-Continuum Reduction of Field Theories: A Route to Seamlessly Bridge Quantum and Atomistic Length-Scales with Continuum

    Science.gov (United States)

    2016-04-01

    this form contains classified information, stamp classification level on the top and bottom of this page. 17. LIMITATION OF ABSTRACT. This block... techniques have been developed that enable large-scale real-space electronic structure calculations using Kohn-Sham density functional theory. In...particular, the various components of the developed techniques include (i) real-space formulation of Kohn-Sham density-functional theory (DFT) for both

  11. Current increment of tunnel field-effect transistor using InGaAs nanowire/Si heterojunction by scaling of channel length

    Science.gov (United States)

    Tomioka, Katsuhiro; Fukui, Takashi

    2014-02-01

    We report on a fabrication of tunnel field-effect transistors using InGaAs nanowire/Si heterojunctions and the characterization of scaling of channel lengths. The devices consisted of single InGaAs nanowires with a diameter of 30 nm grown on p-type Si(111) substrates. The switch demonstrated steep subthreshold-slope (30 mV/decade) at drain-source voltage (VDS) of 0.10 V. Also, pinch-off behavior appeared at moderately low VDS, below 0.10 V. Reducing the channel length of the transistors attained a steep subthreshold slope (<60 mV/decade) and enhanced the drain current, which was 100 higher than that of the longer channels.

  12. Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

    Science.gov (United States)

    Faitsch, M.; Maurizio, R.; Gallo, A.; Coda, S.; Eich, T.; Labit, B.; Merle, A.; Reimerdes, H.; Sieglin, B.; Theiler, C.; the Eurofusion MST1 Team; the TCV Team

    2018-04-01

    This paper reports on experimental observations on TCV with a scan in upper triangularity {δ }up}, including negative triangularity, focusing on the power fall-off length {λ }{{q}} in L-Mode. The upper triangularity is scanned from -0.28 to 0.47. Smaller {λ }{{q}}out} is measured at the outer divertor target for decreasing {δ }up} together with higher edge temperature {T}{{e},{edge}} leading to increased confinement. This effect is observed for both magnetic drift directions for discharges in deuterium and helium. In helium larger {λ }{{q}} values are observed compared to deuterium. The power fall-off length at the inner divertor target {λ }{{q}}in} has a non-monotonic behaviour with changing triangularity. The largest values are around {δ }up}=0. The ratio {λ }{{q}}in}/{λ }{{q}}out} increases for decreasing {δ }up} for positive triangularity and is approximately constant for negative triangularity. {λ }{{q}}out} is compared to available scaling laws. Partial agreement is only observed for a scaling law containing a proxy for {T}{{e},{edge}} at ASDEX Upgrade (Sieglin 2016 Plasma Phys. Control. Fusion 58 055015). Extending this scaling to TCV and using {T}{{e},{edge}} at {ρ }pol}=0.95 suggests that {λ }{{q}}out} is independent of machine size {λ }{{q}}{{L} - {Mode}} ({mm}) = 165\\cdot {B}pol}{({{T}})}-0.66\\cdot A{({{u}})}-0.15\\cdot {T}{{e},{edge}}{({eV})}-0.93\\cdot R{({{m}})}-0.03. Possible explanations for smaller {λ }{{q}}out} for decreasing {δ }up} is a reduction in turbulence or a direct effect of increasing {T}{{e},{edge}}.

  13. Length-displacement scaling of thrust faults on the Moon and the formation of uphill-facing scarps

    Science.gov (United States)

    Roggon, Lars; Hetzel, Ralf; Hiesinger, Harald; Clark, Jaclyn D.; Hampel, Andrea; van der Bogert, Carolyn H.

    2017-08-01

    Fault populations on terrestrial planets exhibit a linear relationship between their length, L, and the maximum displacement, D, which implies a constant D/L ratio during fault growth. Although it is known that D/L ratios of faults are typically a few percent on Earth and 0.2-0.8% on Mars and Mercury, the D/L ratios of lunar faults are not well characterized. Quantifying the D/L ratios of faults on the Moon is, however, crucial for a better understanding of lunar tectonics, including for studies of the amount of global lunar contraction. Here, we use high-resolution digital terrain models to perform a topographic analysis of four lunar thrust faults - Simpelius-1, Morozov (S1), Fowler, and Racah X-1 - that range in length from 1.3 km to 15.4 km. First, we determine the along-strike variation of the vertical displacement from ≥ 20 topographic profiles across each fault. For measuring the vertical displacements, we use a method that is commonly applied to fault scarps on Earth and that does not require detrending of the profiles. The resulting profiles show that the displacement changes gradually along these faults' strike, with maximum vertical displacements ranging from 17 ± 2 m for Simpelius-1 to 192 ± 30 m for Racah X-1. Assuming a fault dip of 30° yields maximum total displacements (D) that are twice as large as the vertical displacements. The linear relationship between D and L supports the inference that lunar faults gradually accumulate displacement as they propagate laterally. For the faults we investigated, the D/L ratio is ∼2.3%, an order of magnitude higher than theoretical predictions for the Moon, but a value similar for faults on Earth. We also employ finite-element modeling and a Mohr circle stress analysis to investigate why many lunar thrust faults, including three of those studied here, form uphill-facing scarps. Our analysis shows that fault slip is preferentially initiated on planes that dip in the same direction as the topography, because

  14. Morphological quantification of hierarchical geomaterials by X-ray nano-CT bridges the gap from nano to micro length scales

    KAUST Repository

    Brisard, S.

    2012-01-30

    Morphological quantification of the complex structure of hierarchical geomaterials is of great relevance for Earth science and environmental engineering, among others. To date, methods that quantify the 3D morphology on length scales ranging from a few tens of nanometers to several hun-dred nanometers have had limited success. We demonstrate, for the first time, that it is possible to go beyond visualization and to extract quantitative morphological information from X-ray images in the aforementioned length scales. As examples, two different hierarchical geomaterials exhibiting complex porous structures ranging from nanometer to macroscopic scale are studied: a flocculated clay water suspension and two hydrated cement pastes. We show that from a single projection image it is possible to perform a direct computation of the ultra-small angle-scattering spectra. The predictions matched very well the experimental data obtained by the best ultra-small angle-scattering experimental setups as observed for the cement paste. In this context, we demonstrate that the structure of flocculated clay suspension exhibit two well-distinct regimes of aggregation, a dense mass fractal aggregation at short distance and a more open structure at large distance, which can be generated by a 3D reaction limited cluster-cluster aggregation process. For the first time, a high-resolution 3D image of fibrillar cement paste cluster was obtained from limited angle nanotomography.

  15. Search for Screened Interactions Associated with Dark Energy below the 100 μm Length Scale.

    Science.gov (United States)

    Rider, Alexander D; Moore, David C; Blakemore, Charles P; Louis, Maxime; Lu, Marie; Gratta, Giorgio

    2016-09-02

    We present the results of a search for unknown interactions that couple to mass between an optically levitated microsphere and a gold-coated silicon cantilever. The scale and geometry of the apparatus enable a search for new forces that appear at distances below 100  μm and which would have evaded previous searches due to screening mechanisms. The data are consistent with electrostatic backgrounds and place upper limits on the strength of new interactions at 5.6×10^{4} in the region of parameter space where the self-coupling Λ≳5  meV and the microspheres are not fully screened.

  16. Incorporating Scale-Dependent Fracture Stiffness for Improved Reservoir Performance Prediction

    Science.gov (United States)

    Crawford, B. R.; Tsenn, M. C.; Homburg, J. M.; Stehle, R. C.; Freysteinson, J. A.; Reese, W. C.

    2017-12-01

    We present a novel technique for predicting dynamic fracture network response to production-driven changes in effective stress, with the potential for optimizing depletion planning and improving recovery prediction in stress-sensitive naturally fractured reservoirs. A key component of the method involves laboratory geomechanics testing of single fractures in order to develop a unique scaling relationship between fracture normal stiffness and initial mechanical aperture. Details of the workflow are as follows: tensile, opening mode fractures are created in a variety of low matrix permeability rocks with initial, unstressed apertures in the micrometer to millimeter range, as determined from image analyses of X-ray CT scans; subsequent hydrostatic compression of these fractured samples with synchronous radial strain and flow measurement indicates that both mechanical and hydraulic aperture reduction varies linearly with the natural logarithm of effective normal stress; these stress-sensitive single-fracture laboratory observations are then upscaled to networks with fracture populations displaying frequency-length and length-aperture scaling laws commonly exhibited by natural fracture arrays; functional relationships between reservoir pressure reduction and fracture network porosity, compressibility and directional permeabilities as generated by such discrete fracture network modeling are then exported to the reservoir simulator for improved naturally fractured reservoir performance prediction.

  17. Nano-regime Length Scales Extracted from the First Sharp Diffraction Peak in Non-crystalline SiO2 and Related Materials: Device Applications

    Directory of Open Access Journals (Sweden)

    Phillips James

    2010-01-01

    Full Text Available Abstract This paper distinguishes between two different scales of medium range order, MRO, in non-crystalline SiO2: (1 the first is ~0.4 to 0.5 nm and is obtained from the position of the first sharp diffraction peak, FSDP, in the X-ray diffraction structure factor, S(Q, and (2 the second is ~1 nm and is calculated from the FSDP full-width-at-half-maximum FWHM. Many-electron calculations yield Si–O third- and O–O fourth-nearest-neighbor bonding distances in the same 0.4–0.5 nm MRO regime. These derive from the availability of empty Si dπ orbitals for back-donation from occupied O pπ orbitals yielding narrow symmetry determined distributions of third neighbor Si–O, and fourth neighbor O–O distances. These are segments of six member rings contributing to connected six-member rings with ~1 nm length scale within the MRO regime. The unique properties of non-crystalline SiO2 are explained by the encapsulation of six-member ring clusters by five- and seven-member rings on average in a compliant hard-soft nano-scaled inhomogeneous network. This network structure minimizes macroscopic strain, reducing intrinsic bonding defects as well as defect precursors. This inhomogeneous CRN is enabling for applications including thermally grown ~1.5 nm SiO2 layers for Si field effect transistor devices to optical components with centimeter dimensions. There are qualitatively similar length scales in nano-crystalline HfO2 and phase separated Hf silicates based on the primitive unit cell, rather than a ring structure. Hf oxide dielectrics have recently been used as replacement dielectrics for a new generation of Si and Si/Ge devices heralding a transition into nano-scale circuits and systems on a Si chip.

  18. Multi-length-scale Material Model for SiC/SiC Ceramic-Matrix Composites (CMCs): Inclusion of In-Service Environmental Effects

    Science.gov (United States)

    Grujicic, M.; Galgalikar, R.; Snipes, J. S.; Ramaswami, S.

    2016-01-01

    In our recent work, a multi-length-scale room-temperature material model for SiC/SiC ceramic-matrix composites (CMCs) was derived and parameterized. The model was subsequently linked with a finite-element solver so that it could be used in a general room-temperature, structural/damage analysis of gas-turbine engine CMC components. Due to its multi-length-scale character, the material model enabled inclusion of the effects of fiber/tow (e.g., the volume fraction, size, and properties of the fibers; fiber-coating material/thickness; decohesion properties of the coating/matrix interfaces; etc.) and ply/lamina (e.g., the 0°/90° cross-ply versus plain-weave architectures, the extent of tow crimping in the case of the plain-weave plies, cohesive properties of the inter-ply boundaries, etc.) length-scale microstructural/architectural parameters on the mechanical response of the CMCs. One of the major limitations of the model is that it applies to the CMCs in their as-fabricated conditions (i.e., the effect of prolonged in-service environmental exposure and the associated material aging-degradation is not accounted for). In the present work, the model is upgraded to include such in-service environmental-exposure effects. To demonstrate the utility of the upgraded material model, it is used within a finite-element structural/failure analysis involving impact of a toboggan-shaped turbine shroud segment by a foreign object. The results obtained clearly revealed the effects that different aspects of the in-service environmental exposure have on the material degradation and the extent of damage suffered by the impacted CMC toboggan-shaped shroud segment.

  19. Water dependency and water exploitation at global scale as indicators of water security

    Science.gov (United States)

    De Roo, A. P. J.; Beck, H.; Burek, P.; Bernard, B.

    2015-12-01

    A water dependency index has been developed indicating the dependency of water consumption from upstream sources of water, sometimes across (multiple) national border. This index is calculated at global scale using the 0.1 global LISFLOOD hydrological modelling system forced by WFDEI meteorological data for the timeframe 1979-2012. The global LISFLOOD model simulates the most important hydrological processes, as well as water abstraction and consumption from various sectors, and flood routing, at daily scale, with sub-timesteps for routing and subgrid parameterization related to elevation and landuse. The model contains also options for water allocation, to allow preferences of water use for particular sectors in water scarce periods. LISFLOOD is also used for the Global Flood Awareness System (GloFAS), the European Flood Awareness System (EFAS), continental scale climate change impact studies on floods and droughts. The water dependency indicator is calculated on a monthly basis, and various annual and multiannual indicators are derived from it. In this study, the indicator will be compared against water security areas known from other studies. Other indicators calculated are the Water Exploitation Index (WEI+), which is a commonly use water security indicator in Europe, and freshwater resources per capita indicators at regional, national and river basin scale. Several climate scnearios are run to indicate future trends in water security.

  20. Intensity limits for propagation of 0.527 μm laser beams through large-scale-length plasmas for inertial confinement fusion

    International Nuclear Information System (INIS)

    Niemann, C.; Divol, L.; Froula, D.H.; Gregori, G.; Jones, O.; Kirkwood, R.K.; MacKinnon, A.J.; Meezan, N.B.; Moody, J.D.; Sorce, C.; Suter, L.J.; Glenzer, S.H.; Bahr, R.; Seka, W.

    2005-01-01

    We have established the intensity limits for propagation of a frequency-doubled (2ω, 527 nm) high intensity interaction beam through an underdense large-scale-length plasma. We observe good beam transmission at laser intensities at or below 2x10 14 W/cm 2 and a strong reduction at intensities up to 10 15 W/cm 2 due to the onset of parametric scattering instabilities. We show that temporal beam smoothing by spectral dispersion allows a factor of 2 higher intensities while keeping the beam spray constant, which establishes frequency-doubled light as an option for ignition and burn in inertial confinement fusion experiments

  1. Seed harvesting by a generalist consumer is context-dependent: Interactive effects across multiple spatial scales

    Science.gov (United States)

    Ostoja, Steven M.; Schupp, Eugene W.; Klinger, Rob

    2013-01-01

    Granivore foraging decisions affect consumer success and determine the quantity and spatial pattern of seed survival. These decisions are influenced by environmental variation at spatial scales ranging from landscapes to local foraging patches. In a field experiment, the effects of seed patch variation across three spatial scales on seed removal by western harvester ants Pogonomyrmex occidentalis were evaluated. At the largest scale we assessed harvesting in different plant communities, at the intermediate scale we assessed harvesting at different distances from ant mounds, and at the smallest scale we assessed the effects of interactions among seed species in local seed neighborhoods on seed harvesting (i.e. resource–consumer interface). Selected seed species were presented alone (monospecific treatment) and in mixture with Bromus tectorum (cheatgrass; mixture treatment) at four distances from P. occidentalis mounds in adjacent intact sagebrush and non-native cheatgrass-dominated communities in the Great Basin, Utah, USA. Seed species differed in harvest, with B. tectorum being least preferred. Large and intermediate scale variation influenced harvest. More seeds were harvested in sagebrush than in cheatgrass-dominated communities (largest scale), and the quantity of seed harvested varied with distance from mounds (intermediate-scale), although the form of the distance effect differed between plant communities. At the smallest scale, seed neighborhood affected harvest, but the patterns differed among seed species considered. Ants harvested fewer seeds from mixed-seed neighborhoods than from monospecific neighborhoods, suggesting context dependence and potential associational resistance. Further, the effects of plant community and distance from mound on seed harvest in mixtures differed from their effects in monospecific treatments. Beyond the local seed neighborhood, selection of seed resources is better understood by simultaneously evaluating removal at

  2. Zooming in and out: Scale dependence of extrinsic and intrinsic factors affecting salt marsh erosion

    Science.gov (United States)

    Wang, Heng; van der Wal, Daphne; Li, Xiangyu; van Belzen, Jim; Herman, Peter M. J.; Hu, Zhan; Ge, Zhenming; Zhang, Liquan; Bouma, Tjeerd J.

    2017-07-01

    Salt marshes are valuable ecosystems that provide important ecosystem services. Given the global scale of marsh loss due to climate change and coastal squeeze, there is a pressing need to identify the critical extrinsic (wind exposure and foreshore morphology) and intrinsic factors (soil and vegetation properties) affecting the erosion of salt marsh edges. In this study, we quantified rates of cliff lateral retreat (i.e., the eroding edge of a salt marsh plateau) using a time series of aerial photographs taken over four salt marsh sites in the Westerschelde estuary, the Netherlands. In addition, we experimentally quantified the erodibility of sediment cores collected from the marsh edge of these four marshes using wave tanks. Our results revealed the following: (i) at the large scale, wind exposure and the presence of pioneer vegetation in front of the cliff were the key factors governing cliff retreat rates; (ii) at the intermediate scale, foreshore morphology was partially related to cliff retreat; (iii) at the local scale, the erodibility of the sediment itself at the marsh edge played a large role in determining the cliff retreat rate; and (iv) at the mesocosm scale, cliff erodibility was determined by soil properties and belowground root biomass. Thus, both extrinsic and intrinsic factors determined the fate of the salt marsh but at different scales. Our study highlights the importance of understanding the scale dependence of the factors driving the evolution of salt marsh landscapes.

  3. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators.

    Science.gov (United States)

    Strickland, Bradley A; Vilella, Francisco J; Belant, Jerrold L

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  4. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators.

    Directory of Open Access Journals (Sweden)

    Bradley A Strickland

    Full Text Available Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17 on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their

  5. Scale-dependent habitat selection and size-based dominance in adult male American alligators

    Science.gov (United States)

    Strickland, Bradley A.; Vilella, Francisco; Belant, Jerrold L.

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  6. Synthesizing mechanisms of density dependence in reef fishes: behavior, habitat configuration, and observational scale.

    Science.gov (United States)

    White, J Wilson; Samhouri, Jameal F; Stier, Adrian C; Wormald, Clare L; Hamilton, Scott L; Sandin, Stuart A

    2010-07-01

    Coral and rocky reef fish populations are widely used as model systems for the experimental exploration of density-dependent vital rates, but patterns of density-dependent mortality in these systems are not yet fully understood. In particular, the paradigm for strong, directly density-dependent (DDD) postsettlement mortality stands in contrast to recent evidence for inversely density-dependent (IDD) mortality. We review the processes responsible for DDD and IDD per capita mortality in reef fishes, noting that the pattern observed depends on predator and prey behavior, the spatial configuration of the reef habitat, and the spatial and temporal scales of observation. Specifically, predators tend to produce DDD prey mortality at their characteristic spatial scale of foraging, but prey mortality is IDD at smaller spatial scales due to attack-abatement effects (e.g., risk dilution). As a result, DDD mortality may be more common than IDD mortality on patch reefs, which tend to constrain predator foraging to the same scale as prey aggregation, eliminating attack-abatement effects. Additionally, adjacent groups of prey on continuous reefs may share a subset of refuges, increasing per capita refuge availability and relaxing DDD mortality relative to prey on patch reefs, where the patch edge could prevent such refuge sharing. These hypotheses lead to a synthetic framework to predict expected mortality patterns for a variety of scenarios. For nonsocial, nonaggregating species and species that aggregate in order to take advantage of spatially clumped refuges, IDD mortality is possible but likely superseded by DDD refuge competition, especially on patch reefs. By contrast, for species that aggregate socially, mortality should be IDD at the scale of individual aggregations but DDD at larger scales. The results of nearly all prior reef fish studies fit within this framework, although additional work is needed to test many of the predicted outcomes. This synthesis reconciles some

  7. The Influence of Web- versus Paper-Based Formats on the Assessment of Tobacco Dependence: Evaluating the Measurement Invariance of the Dimensions of Tobacco Dependence Scale

    Directory of Open Access Journals (Sweden)

    Chris G. Richardson

    2009-01-01

    Full Text Available The purpose of this study was to examine the influence of mode of administration (internet-based, web survey format versus pencil-and-paper format on responses to the Dimensions of Tobacco Dependence Scale (DTDS. Responses from 1,484 adolescents that reported using tobacco (mean age 16 years were examined; 354 (23.9% participants completed a web-based version and 1,130 (76.1% completed a paper-based version of the survey. Both surveys were completed in supervised classroom environments. Use of the web-based format was associated with significantly shorter completion times and a small but statistically significant increase in the number of missing responses. Tests of measurement invariance indicated that using a web-based mode of administration did not influence the psychometric functioning of the DTDS. There were no significant differences between the web- and paper-based groups' ratings of the survey's length, their question comprehension, and their response accuracy. Overall, the results of the study support the equivalence of scores obtained from web- and paper-based versions of the DTDS in secondary school settings.

  8. The X-factor in Galaxies: I. Dependence on Environment and Scale

    Energy Technology Data Exchange (ETDEWEB)

    Feldmann, Robert; /Fermilab /Chicago U., EFI; Gnedin, Nickolay Y.; /Fermilab /Chicago U., EFI /Chicago U.; Kravtsov, Andrey V.; /Chicago U., EFI /Chicago U.

    2011-12-01

    Characterizing the conversion factor between CO emission and column density of molecular hydrogen, X{sub CO}, is crucial in studying the gaseous content of galaxies, its evolution, and relation to star formation. In most cases the conversion factor is assumed to be close to that of giant molecular clouds (GMCs) in the Milky Way, except possibly for mergers and star-bursting galaxies. However, there are physical grounds to expect that it should also depend on the gas metallicity, surface density, and strength of the interstellar radiation field. The X{sub CO} factor may also depend on the scale on which CO emission is averaged due to effects of limited resolution. We study the dependence of X{sub CO} on gas properties and averaging scale using a model that is based on a combination of results of sub-pc scale magneto-hydrodynamic simulations and on the gas distribution from self-consistent cosmological simulations of galaxy formation. Our model predicts X{sub CO} {approx} 2 - 4 x 10{sup 20} K{sup -1} cm{sup -2} km{sup -1} s, consistent with the Galactic value, for interstellar medium conditions typical for the Milky Way. For such conditions the predicted X{sub CO} varies by only a factor of two for gas surfaced densities in the range {Sigma}{sub H{sub 2}} {approx} 50-500 M{sub {circle_dot}} pc{sup -2}. However, the model also predicts that more generally on the scale of GMCs, X{sub CO} is a strong function of metallicity, and depends on the column density and the interstellar UV flux. We show explicitly that neglecting these dependencies in observational estimates can strongly bias the inferred distribution of H2 column densities of molecular clouds to have a narrower and offset range compared to the true distribution. We find that when averaged on {approx} kpc scales the X-factor depends only weakly on radiation field and column density, but is still a strong function of metallicity. The predicted metallicity dependence can be approximated as X{sub CO} {proportional

  9. Linking the influence and dependence of people on biodiversity across scales

    Science.gov (United States)

    Isbell, Forest; Gonzalez, Andrew; Loreau, Michel; Cowles, Jane; Díaz, Sandra; Hector, Andy; Mace, Georgina M.; Wardle, David A.; O’Connor, Mary I.; Duffy, J. Emmett; Turnbull, Lindsay A.; Thompson, Patrick L.; Larigauderie, Anne

    2017-01-01

    Biodiversity enhances many of nature’s benefits to people, including the regulation of climate and the production of wood in forests, livestock forage in grasslands and fish in aquatic ecosystems. Yet people are now driving the sixth mass extinction event in Earth’s history. Human dependence and influence on biodiversity have mainly been studied separately and at contrasting scales of space and time, but new multiscale knowledge is beginning to link these relationships. Biodiversity loss substantially diminishes several ecosystem services by altering ecosystem functioning and stability, especially at the large temporal and spatial scales that are most relevant for policy and conservation. PMID:28569811

  10. Linking the influence and dependence of people on biodiversity across scales.

    Science.gov (United States)

    Isbell, Forest; Gonzalez, Andrew; Loreau, Michel; Cowles, Jane; Díaz, Sandra; Hector, Andy; Mace, Georgina M; Wardle, David A; O'Connor, Mary I; Duffy, J Emmett; Turnbull, Lindsay A; Thompson, Patrick L; Larigauderie, Anne

    2017-05-31

    Biodiversity enhances many of nature's benefits to people, including the regulation of climate and the production of wood in forests, livestock forage in grasslands and fish in aquatic ecosystems. Yet people are now driving the sixth mass extinction event in Earth's history. Human dependence and influence on biodiversity have mainly been studied separately and at contrasting scales of space and time, but new multiscale knowledge is beginning to link these relationships. Biodiversity loss substantially diminishes several ecosystem services by altering ecosystem functioning and stability, especially at the large temporal and spatial scales that are most relevant for policy and conservation.

  11. Conducting polymer diffraction gratings on gold surfaces created by microcontact printing and electropolymerization at submicron length scales.

    Science.gov (United States)

    Marikkar, F Saneeha; Carter, Chet; Kieltyka, Kathy; Robertson, Joseph W F; Williamson, Cathie; Simmonds, Adam; Zangmeister, Rebecca; Fritz, Torsten; Armstrong, Neal R

    2007-09-25

    Conducting polymer diffraction gratings on Au substrates have been created using microcontact printing of C18-alkanethiols, followed by electropolymerization of either poly(aniline) (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT). Soft-polymer replicas of simple diffraction grating masters (1200 lines/mm) were used to define the alkanethiol template for polymer growth. Growth of PANI and PEDOT diffraction gratings was followed in real time, through in situ tapping-mode atomic force microscopy, and by monitoring diffraction efficiency (DE) as a function of grating depth. DE increased as grating depth increased, up to a limiting efficiency (13-26%, with white light illumination), defined by the combined optical properties of the grating and the Au substrate, and ultimately limited by the loss of resolution due to coalescence of the polymer films. Grating efficiency is strongly dependent upon the grating depth and the refractive index contrast between the grating material and the surrounding solutions. Both PEDOT and PANI gratings show refractive index changes as a function of applied potential, consistent with changes in refractive index brought about by the doping/dedoping of the conducting polymer. The DE of PANI gratings are strongly dependent on the pH of the superstrate solution; the maximum sensitivity (DeltaDE/DeltapH) is achieved with PANI gratings held at +0.4 V versus Ag/AgCl, where the redox chemistry is dominated by the acid-base equilibrium between the protonated (emeraldine salt) and deprotonated (emeraldine base) forms of PANI. Simulations of DE were conducted for various combinations of conducting polymer refractive index and grating depth, to compute sensitivity parameters, which are maximized when the grating depth is ca. 50% of its maximum obtainable depth.

  12. Origin of Scale-Dependent Dispersivity and Its Implications For Miscible Gas Flooding

    Energy Technology Data Exchange (ETDEWEB)

    Steven Bryant; Russ Johns; Larry Lake; Thomas Harmon

    2008-09-30

    Dispersive mixing has an important impact on the effectiveness of miscible floods. Simulations routinely assume Fickian dispersion, yet it is well established that dispersivity depends on the scale of measurement. This is one of the main reasons that a satisfactory method for design of field-scale miscible displacement processes is still not available. The main objective of this project was to improve the understanding of the fundamental mechanisms of dispersion and mixing, particularly at the pore scale. To this end, microsensors were developed and used in the laboratory to measure directly the solute concentrations at the scale of individual pores; the origin of hydrodynamic dispersion was evaluated from first principles of laminar flow and diffusion at the grain scale in simple but geometrically completely defined porous media; techniques to use flow reversal to distinguish the contribution to dispersion of convective spreading from that of true mixing; and the field scale impact of permeability heterogeneity on hydrodynamic dispersion was evaluated numerically. This project solved a long-standing problem in solute transport in porous media by quantifying the physical basis for the scaling of dispersion coefficient with the 1.2 power of flow velocity. The researchers also demonstrated that flow reversal uniquely enables a crucial separation of irreversible and reversible contributions to mixing. The interpretation of laboratory and field experiments that include flow reversal provides important insight. Other advances include the miniaturization of long-lasting microprobes for in-situ, pore-scale measurement of tracers, and a scheme to account properly in a reservoir simulator (grid-block scale) for the contributions of convective spreading due to reservoir heterogeneity and of mixing.

  13. Very-long-chain aldehydes promote in vitro prepenetration processes of Blumeria graminis in a dose- and chain length-dependent manner.

    Science.gov (United States)

    Hansjakob, Anton; Bischof, Sebastian; Bringmann, Gerhard; Riederer, Markus; Hildebrandt, Ulrich

    2010-12-01

    Surface properties of aerial plant organs have been shown to affect the interaction of fungal plant pathogens and their hosts. Conidial germination and differentiation - the so-called prepenetration processes - of the barley powdery mildew fungus (Blumeria graminis f. sp. hordei) are known to be triggered by n-hexacosanal (C(26)-aldehyde), a minor constituent of barley leaf wax. In order to analyze the differentiation-inducing capabilities of typical aldehyde wax constituents on conidia of wheat and barley powdery mildew, synthetic even-numbered very-long-chain aldehydes (C(22)-C(30)) were assayed, applying an in vitro system based on Formvar(®)/n-hexacosane-coated glass slides. n-Hexacosanal was the most effective aldehyde tested. Germination and differentiation rates of powdery mildew conidia increased with increasing concentrations of very-long-chain aldehydes. Relative to n-hexacosanal, the other aldehyde compounds showed a gradual decrease in germination- and differentiation-inducing capabilities with both decreasing and increasing chain length. In addition to n-hexacosanal, several other ubiquitous very-long-chain aldehyde wax constituents were capable of effectively stimulating B. graminis prepenetration processes in a dose- and chain length-dependent manner. Other wax constituents, such as n-alkanes, primary alcohols (with the exception of n-hexacosanol), fatty acids and alkyl esters, did not affect fungal prepenetration. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

  14. Bond length (Ti-O) dependence of nano ATO3-based (A = Pb, Ba, Sr) perovskite structures: Optical investigation in IR range

    Science.gov (United States)

    Ghasemifard, Mahdi; Ghamari, Misagh; Okay, Cengiz

    2018-01-01

    In the current study, ABO3 (A = Pb, Ba, Sr and B = Ti) perovskite structures are produced by the auto-combustion route by using citric acid (CA) and nitric acid (NA) as fuel and oxidizer. The X-ray diffraction (XRD) patterns confirmed the perovskite nanostructure with cubic, tetragonal, and rhombohedral for SrTiO3, PbTiO3, and BaTiO3, respectively. Using Scherrer’s equation and XRD pattern, the average crystallite size of the samples were acquired. The effect of Ti-O bond length on the structure of the samples was evaluated. The type of structures obtained depends on Ti-O bond length which is in turn influenced by A2+ substitutions. Microstructural studies of nanostructures calcined at 850∘C confirmed the formation of polyhedral particles with a narrow size distribution. The values of optical band gaps were measured and the impact of A2+ was discussed. The optical properties such as the complex refractive index and dielectric function were calculated by IR spectroscopy and Kramers-Kronig (K-K) relations. Lead, as the element with the highest density as compared to other elements, changes the optical constants, remarkably due to altering titanium and oxygen distance in TO6 groups.

  15. Magnetoresistance of untwinned YBa(2)Cu(3)O(y) single crystals in a wide range of doping: anomalous hole-doping dependence of the coherence length.

    Science.gov (United States)

    Ando, Yoichi; Segawa, Kouji

    2002-04-22

    Magnetoresistance (MR) in the a-axis resistivity of untwinned YBa(2)Cu(3)O(y) single crystals is measured for a wide range of doping ( y = 6.45-7.0). The y dependence of the in-plane coherence length xi(ab) estimated from the fluctuation magnetoconductance indicates that the superconductivity is anomalously weakened in the 60-K phase; this observation, together with the Hall coefficient and the a-axis thermopower data which suggest the hole doping to be 12% for y approximately equal to 6.65, gives evidence that the origin of the 60-K plateau is the 1/8 anomaly. At high temperatures, the normal-state MR data show signatures of the Zeeman effect on the pseudogap in underdoped samples.

  16. Dynamics of a bright soliton in Bose-Einstein condensates with time-dependent atomic scattering length in an expulsive parabolic potential

    International Nuclear Information System (INIS)

    Liang, Z.X.; Zhang, Z.D.; Liu, W.M.

    2005-01-01

    We present a family of exact solutions of the one-dimensional nonlinear Schroedinger equation which describes the dynamics of a bright soliton in Bose-Einstein condensates with the time-dependent interatomic interaction in an expulsive parabolic potential. Our results show that, under a safe range of parameters, the bright soliton can be compressed into very high local matter densities by increasing the absolute value of the atomic scattering length, which can provide an experimental tool for investigating the range of validity of the one-dimensional Gross-Pitaevskii equation. We also find that the number of atoms in the bright soliton keeps dynamic stability: a time-periodic atomic exchange is formed between the bright soliton and the background

  17. Biodiversity change is scale-dependent: an example from Dutch and UK hoverflies (Diptera, Syrphidae)

    NARCIS (Netherlands)

    Keil, P.; Biesmeijer, J.C.; Barendregt, A.; Reemer, M.; Kunin, W.E.

    2011-01-01

    We test whether temporal change in species richness (ΔS [%]) is scale-dependent, using data on hoverflies from the UK and the Netherlands. We analysed ΔS between pre-1980 and post-1980 periods using 5 grid resolutions (10×10, 20×20, 40×40, 80×80 and 160×160 km). We also tested the effect of data

  18. Scale-dependent climatic drivers of human epidemics in ancient China

    Czech Academy of Sciences Publication Activity Database

    Tian, H.; Yan, Ch.; Xu, L.; Büntgen, Ulf; Stenseth, N. C.; Zhang, Z.

    2017-01-01

    Roč. 114, č. 49 (2017), s. 12970-12975 ISSN 0027-8424 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : infectious-diseases * northern-hemisphere * cholera dynamics * time-series * 2 millennia * reconstruction * variability * management * plague * ad * epidemics * climate * scale dependent * natural disaster * disease Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 9.661, year: 2016

  19. Phase Behavior of Blends of Linear and Branched Polyethylenes on Micron-Length Scales via Ultra-Small-Angle Neutron Scattering (USANS)

    International Nuclear Information System (INIS)

    Agamalian, M.M.; Alamo, R.G.; Londono, J.D.; Mandelkern, L.; Wignall, G.D.

    1999-01-01

    SANS experiments on blends of linear, high density (HD) and long chain branched, low density (LD) polyethylenes indicate that these systems form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole cameras is approximately equal to 10 3 and it has therefore been suggested that data might also be interpreted as arising from a bi-phasic melt with large a particle size ( 1 m), because most of the scattering from the different phases would not be resolved. We have addressed this hypothesis by means of USANS experiments, which confirm that HDPEILDPE blends are homogenous in the melt on length scales up to 20 m. We have also studied blends of HDPE and short-chain branched linear low density polyethylenes (LLDPEs), which phase separate when the branch content is sufficiently high. LLDPEs prepared with Ziegler-Natta catalysts exhibit a wide distribution of compositions, and may therefore be thought of as a blend of different species. When the composition distribution is broad enough, a fraction of highly branched chains may phase separate on m-length scales, and USANS has also been used to quantify this phenomenon

  20. Redshift space correlations and scale-dependent stochastic biasing of density peaks

    Science.gov (United States)

    Desjacques, Vincent; Sheth, Ravi K.

    2010-01-01

    We calculate the redshift space correlation function and the power spectrum of density peaks of a Gaussian random field. Our derivation, which is valid on linear scales k≲0.1hMpc-1, is based on the peak biasing relation given by Desjacques [Phys. Rev. DPRVDAQ1550-7998, 78, 103503 (2008)10.1103/PhysRevD.78.103503]. In linear theory, the redshift space power spectrum is Ppks(k,μ)=exp⁡(-f2σvel2k2μ2)[bpk(k)+bvel(k)fμ2]2Pδ(k), where μ is the angle with respect to the line of sight, σvel is the one-dimensional velocity dispersion, f is the growth rate, and bpk(k) and bvel(k) are k-dependent linear spatial and velocity bias factors. For peaks, the value of σvel depends upon the functional form of bvel. When the k dependence is absent from the square brackets and bvel is set to unity, the resulting expression is assumed to describe models where the bias is linear and deterministic, but the velocities are unbiased. The peak model is remarkable because it has unbiased velocities in this same sense—peak motions are driven by dark matter flows—but, in order to achieve this, bvel must be k dependent. We speculate that this is true in general: k dependence of the spatial bias will lead to k dependence of bvel even if the biased tracers flow with the dark matter. Because of the k dependence of the linear bias parameters, standard manipulations applied to the peak model will lead to k-dependent estimates of the growth factor that could erroneously be interpreted as a signature of modified dark energy or gravity. We use the Fisher formalism to show that the constraint on the growth rate f is degraded by a factor of 2 if one allows for a k-dependent velocity bias of the peak type. Our analysis also demonstrates that the Gaussian smoothing term is part and parcel of linear theory. We discuss a simple estimate of nonlinear evolution and illustrate the effect of the peak bias on the redshift space multipoles. For k≲0.1hMpc-1, the peak bias is deterministic but k

  1. Cosmological observables, IR growth of fluctuations, and scale-dependent anisotropies

    DEFF Research Database (Denmark)

    B. Giddings, Steven; Sloth, Martin Snoager

    2011-01-01

    We extend semiclassical methods in inflationary cosmology that capture leading IR corrections to correlators. Such large IR effects can be absorbed into a coordinate change when examining sufficiently local observables, but not when comparing observations at large separation in scales, such as seen...... by a late-time observer. The analysis is facilitated by definition of a scale-dependent metric and physical momentum. These assist definition of "IR-safe" observables seen by a post-inflationary observer, which are contrasted to those based on the local geometry of the reheating surface....... For such observables, the observer's horizon provides an effective IR cutoff. IR growth contributes to enhanced statistical inhomogeneities/anisotropies at short scales, observation of which by a present day observer might be sought in 21 cm measurements. Such IR corrections are argued to grow large for a very late...

  2. Testing scale-dependent effects of seminatural habitats on farmland biodiversity.

    Science.gov (United States)

    Dainese, Matteo; Luna, Diego Inclán; Sitzia, Tommaso; Marini, Lorenzo

    2015-09-01

    The effectiveness of conservation interventions for maximizing biodiversity benefits from agri-environment schemes (AESs) is expected to depend on the quantity of seminatural habitats in the surrounding landscape. To verify this hypothesis, we developed a hierarchical sampling design to assess the effects of field boundary type and cover of seminatural habitats in the landscape at two nested spatial scales. We sampled three types of field boundaries with increasing structural complexity (grass margin, simple hedgerow, complex hedgerow) in paired landscapes with the presence or absence of seminatural habitats (radius 0.5 km), that in turn, were nested within 15 areas with different proportions of seminatural habitats at a larger spatial scale (10 X 10 km). Overall, 90 field boundaries were sampled across a Mediterranean'region (northeastern Italy). We considered species richness response across three different taxonomic groups: vascular plants, butterflies, and tachinid flies. No interactions between type of field boundary and surrounding landscape were found at either 0.5 and 10 km, indicating that the quality of field boundary had the same effect irrespective of the cover of seminatural habitats. At the local scale, extended-width grass margins yielded higher plant species richness, while hedgerows yielded higher species richness of butterflies and tachinids. At the 0.5-km landscape scale, the effect of the proportion of seminatural habitats was neutral for plants and tachinids, while butterflies were positively related to the proportion of forest. At the 10-km landscape scale, only butterflies responded positively to the proportion of seminatural habitats. Our study confirmed the importance of testing multiple scales when considering species from different taxa and with different mobility. We showed that the quality of field boundaries at the local scale was an important factor in enhancing farmland biodiversity. For butterflies, AESs should focus particular

  3. The mass dependence of dark matter halo alignments with large-scale structure

    Science.gov (United States)

    Piras, Davide; Joachimi, Benjamin; Schäfer, Björn Malte; Bonamigo, Mario; Hilbert, Stefan; van Uitert, Edo

    2018-02-01

    Tidal gravitational forces can modify the shape of galaxies and clusters of galaxies, thus correlating their orientation with the surrounding matter density field. We study the dependence of this phenomenon, known as intrinsic alignment (IA), on the mass of the dark matter haloes that host these bright structures, analysing the Millennium and Millennium-XXL N-body simulations. We closely follow the observational approach, measuring the halo position-halo shape alignment and subsequently dividing out the dependence on halo bias. We derive a theoretical scaling of the IA amplitude with mass in a dark matter universe, and predict a power law with slope βM in the range 1/3 to 1/2, depending on mass scale. We find that the simulation data agree with each other and with the theoretical prediction remarkably well over three orders of magnitude in mass, with the joint analysis yielding an estimate of β M = 0.36^{+0.01}_{-0.01}. This result does not depend on redshift or on the details of the halo shape measurement. The analysis is repeated on observational data, obtaining a significantly higher value, β M = 0.56^{+0.05}_{-0.05}. There are also small but significant deviations from our simple model in the simulation signals at both the high- and low-mass end. We discuss possible reasons for these discrepancies, and argue that they can be attributed to physical processes not captured in the model or in the dark matter-only simulations.

  4. Optimal smoothing length scale for actuator line models of wind turbine blades based on Gaussian body force distribution: Wind energy, actuator line model

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Tossas, L. A. [Department of Mechanical Engineering, Johns Hopkins University, Baltimore 21218 MD USA; Churchfield, M. J. [National Renewable Energy Laboratory, Golden 80401 CO USA; Meneveau, C. [Department of Mechanical Engineering, Johns Hopkins University, Baltimore 21218 MD USA

    2017-01-20

    The actuator line model (ALM) is a commonly used method to represent lifting surfaces such as wind turbine blades within large-eddy simulations (LES). In the ALM, the lift and drag forces are replaced by an imposed body force that is typically smoothed over several grid points using a Gaussian kernel with some prescribed smoothing width e. To date, the choice of e has most often been based on numerical considerations related to the grid spacing used in LES. However, especially for finely resolved LES with grid spacings on the order of or smaller than the chord length of the blade, the best choice of e is not known. In this work, a theoretical approach is followed to determine the most suitable value of e, based on an analytical solution to the linearized inviscid flow response to a Gaussian force. We find that the optimal smoothing width eopt is on the order of 14%-25% of the chord length of the blade, and the center of force is located at about 13%-26% downstream of the leading edge of the blade for the cases considered. These optimal values do not depend on angle of attack and depend only weakly on the type of lifting surface. It is then shown that an even more realistic velocity field can be induced by a 2-D elliptical Gaussian lift-force kernel. Some results are also provided regarding drag force representation.

  5. Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2

    Science.gov (United States)

    Radulescu, Aurel; Szekely, Noemi Kinga; Appavou, Marie-Sousai; Pipich, Vitaliy; Kohnke, Thomas; Ossovyi, Vladimir; Staringer, Simon; Schneider, Gerald J.; Amann, Matthias; Zhang-Haagen, Bo; Brandl, Georg; Drochner, Matthias; Engels, Ralf; Hanslik, Romuald; Kemmerling, Günter

    2016-01-01

    The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to µm. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10-4 and 0.5 Å-1 by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper) methods, while simultaneously providing high-neutron intensities with an adjustable resolution. Because of its ability to adjust the intensity and the resolution within wide limits during the experiment, combined with the possibility to equip specific sample environments and ancillary devices, the KWS-2 shows a high versatility in addressing the broad range of structural and morphological studies in the field. Equilibrium structures can be studied in static measurements, while dynamic and kinetic processes can be investigated over time scales between minutes to tens of milliseconds with time-resolved approaches. Typical systems that are investigated with the KWS-2 cover the range from complex, hierarchical systems that exhibit multiple structural levels (e.g., gels, networks, or macro-aggregates) to small and poorly-scattering systems (e.g., single polymers or proteins in solution). The recent upgrade of the detection system, which enables the detection of count rates in the MHz range, opens new opportunities to study even very small biological morphologies in buffer solution with weak scattering signals close to the buffer scattering level at high Q. In this paper, we provide a protocol to investigate samples with characteristic size levels spanning a wide length scale and exhibiting ordering in the mesoscale structure using KWS-2. We present in detail how to use the multiple working modes that are offered by the instrument and the level of performance that is achieved. PMID:28060296

  6. A dual length scale method for plane-wave-based, simulation studies of chemical systems modeled using mixed ab initio/empirical force field descriptions

    Science.gov (United States)

    Yarne, Dawn A.; Tuckerman, Mark E.; Martyna, Glenn J.

    2001-08-01

    Mixed ab initio/empirical force-field simulation studies, calculations in which one part of the system is treated using a fully ab initio description and another part is treated using an empirical description, are becoming increasingly popular. Here, the ability of the commonly used, plane wave-based generalized gradient approximation to density functional theory is extended to model systems in which the electrons are assumed to be localized in a single small region of space, that is, itself, embedded within a large chemically inert bath. This is accomplished by introducing two length scales, so that the rapidly varying, short range, electron-electron and electron-atom interactions, arising from the region where the electrons are localized, can be treated using an appropriately large plane wave basis, while the corresponding, slowly varying, long range interactions of the electrons with the full system or bath, can be treated using a small basis. Briefly, a novel Cardinal B-spline based formalism is employed to derive a smooth, differentiable, and rapidly convergent (with respect to the small basis) expression for the total electronic energy, which explicitly contains the two length scales. The method allows reciprocal space based techniques designed to treat clusters, wires, surfaces and solids/liquids (open, and 1-D and 2-D periodic boundary conditions, respectively) to be utilized. Other plane wave-based "mixed" methods are restricted to clusters. The new methodology, which scales as N log N at fixed size of the chemically active region, has been implemented for parallel computing platforms and tested through applications to both model and realistic problems including an enzyme, human carbonic anhydrase II solvated in an explicit bath of water molecules.

  7. Quinoidal Oligo(9,10-anthryl)s with Chain-Length-Dependent Ground States: A Balance between Aromatic Stabilization and Steric Strain Release

    KAUST Repository

    Lim, Zhenglong

    2015-11-12

    Quinoidal π-conjugated polycyclic hydrocarbons have attracted intensive research interest due to their unique optical/electronic properties and possible magnetic activity, which arises from a thermally excited triplet state. However, there is still lack of fundamental understanding on the factors that determine the electronic ground states. Herein, by using quinoidal oligo(9,10-anthryl)s, it is demonstrated that both aromatic stabilisation and steric strain release play balanced roles in determining the ground states. Oligomers with up to four anthryl units were synthesised and their ground states were investigated by electronic absorption and electron spin resonance (ESR) spectroscopy, assisted by density functional theory (DFT) calculations. The quinoidal 9,10-anthryl dimer 1 has a closed-shell ground state, whereas the tri- (2) and tetramers (3) both have an open-shell diradical ground state with a small singlet-triplet gap. Such a difference results from competition between two driving forces: the large steric repulsion between the anthryl/phenyl units in the closed-shell quinoidal form that drives the molecule to a flexible open-shell diradical structure, and aromatic stabilisation due to the gain of more aromatic sextet rings in the closed-shell form, which drives the molecule towards a contorted quinoidal structure. The ground states of these oligomers thus depend on the overall balance between these two driving forces and show chain-length dependence. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Scale-dependence of processes structuring dung beetle metacommunities using functional diversity and community deconstruction approaches.

    Directory of Open Access Journals (Sweden)

    Pedro Giovâni da Silva

    Full Text Available Community structure is driven by mechanisms linked to environmental, spatial and temporal processes, which have been successfully addressed using metacommunity framework. The relative importance of processes shaping community structure can be identified using several different approaches. Two approaches that are increasingly being used are functional diversity and community deconstruction. Functional diversity is measured using various indices that incorporate distinct community attributes. Community deconstruction is a way to disentangle species responses to ecological processes by grouping species with similar traits. We used these two approaches to determine whether they are improvements over traditional measures (e.g., species composition, abundance, biomass for identification of the main processes driving dung beetle (Scarabaeinae community structure in a fragmented mainland-island landscape in southern Brazilian Atlantic Forest. We sampled five sites in each of four large forest areas, two on the mainland and two on the island. Sampling was performed in 2012 and 2013. We collected abundance and biomass data from 100 sampling points distributed over 20 sampling sites. We studied environmental, spatial and temporal effects on dung beetle community across three spatial scales, i.e., between sites, between areas and mainland-island. The γ-diversity based on species abundance was mainly attributed to β-diversity as a consequence of the increase in mean α- and β-diversity between areas. Variation partitioning on abundance, biomass and functional diversity showed scale-dependence of processes structuring dung beetle metacommunities. We identified two major groups of responses among 17 functional groups. In general, environmental filters were important at both local and regional scales. Spatial factors were important at the intermediate scale. Our study supports the notion of scale-dependence of environmental, spatial and temporal processes in

  9. Scale-dependence of processes structuring dung beetle metacommunities using functional diversity and community deconstruction approaches.

    Science.gov (United States)

    Silva, Pedro Giovâni da; Hernández, Malva Isabel Medina

    2015-01-01

    Community structure is driven by mechanisms linked to environmental, spatial and temporal processes, which have been successfully addressed using metacommunity framework. The relative importance of processes shaping community structure can be identified using several different approaches. Two approaches that are increasingly being used are functional diversity and community deconstruction. Functional diversity is measured using various indices that incorporate distinct community attributes. Community deconstruction is a way to disentangle species responses to ecological processes by grouping species with similar traits. We used these two approaches to determine whether they are improvements over traditional measures (e.g., species composition, abundance, biomass) for identification of the main processes driving dung beetle (Scarabaeinae) community structure in a fragmented mainland-island landscape in southern Brazilian Atlantic Forest. We sampled five sites in each of four large forest areas, two on the mainland and two on the island. Sampling was performed in 2012 and 2013. We collected abundance and biomass data from 100 sampling points distributed over 20 sampling sites. We studied environmental, spatial and temporal effects on dung beetle community across three spatial scales, i.e., between sites, between areas and mainland-island. The γ-diversity based on species abundance was mainly attributed to β-diversity as a consequence of the increase in mean α- and β-diversity between areas. Variation partitioning on abundance, biomass and functional diversity showed scale-dependence of processes structuring dung beetle metacommunities. We identified two major groups of responses among 17 functional groups. In general, environmental filters were important at both local and regional scales. Spatial factors were important at the intermediate scale. Our study supports the notion of scale-dependence of environmental, spatial and temporal processes in the distribution

  10. Multi-scale simulations of droplets in generic time-dependent flows

    Science.gov (United States)

    Milan, Felix; Biferale, Luca; Sbragaglia, Mauro; Toschi, Federico

    2017-11-01

    We study the deformation and dynamics of droplets in time-dependent flows using a diffuse interface model for two immiscible fluids. The numerical simulations are at first benchmarked against analytical results of steady droplet deformation, and further extended to the more interesting case of time-dependent flows. The results of these time-dependent numerical simulations are compared against analytical models available in the literature, which assume the droplet shape to be an ellipsoid at all times, with time-dependent major and minor axis. In particular we investigate the time-dependent deformation of a confined droplet in an oscillating Couette flow for the entire capillary range until droplet break-up. In this way these multi component simulations prove to be a useful tool to establish from ``first principles'' the dynamics of droplets in complex flows involving multiple scales. European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No 642069. & European Research Council under the European Community's Seventh Framework Program, ERC Grant Agreement No 339032.

  11. Development and psychometric evaluation of the psychological cigarette dependence scale for male smokers in taiwan.

    Science.gov (United States)

    Huang, Chih-Ling; Cheng, Chung-Ping; Wang, Hsiu-Hung

    2014-06-01

    The influence of psychological factors on cigarette dependence often surpasses the direct effects of the nicotine itself. Researcher opinions on the nature and extent of psychological contributors to cigarette dependence vary widely. This study develops and psychometrically tests the Psychological Cigarette Dependence Scale (PCDS) for male smokers in Taiwan. The PCDS was developed using domain identification, individual interviews for item generation, expert reviews, and testing for construct validity and instrument stability. After initial item analysis, the PCDS was tested for concurrent and construct validity and reliability on 256 adult male smokers recruited from community centers, trade and business organizations, private companies, and factories in southern Taiwan. Participants were limited to adult men because female smokers are a small (4.1%) proportion of the female population in Taiwan and thus are difficult to recruit in statistically significant numbers. Exploratory factor analysis showed that lifelong binding and health concerns are the two predominating factors addressed by the 37-item PCDS. The PCDS correlated positively with the Fagerstrom questionnaire (r = .54, p psychological cigarette dependence. Assessment results may help nursing professionals focus on smoking cessation interventions that are tailored to the patterns and severity of patients' psychological cigarette dependence.

  12. Overview of lower length scale model development for accident tolerant fuels regarding U3Si2 fuel and FeCrAl cladding

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yongfeng [Idaho National Laboratory

    2016-09-01

    U3Si2 and FeCrAl have been proposed as fuel and cladding concepts, respectively, for accident tolerance fuels with higher tolerance to accident scenarios compared to UO2. However, a lot of key physics and material properties regarding their in-pile performance are yet to be explored. To accelerate the understanding and reduce the cost of experimental studies, multiscale modeling and simulation are used to develop physics-based materials models to assist engineering scale fuel performance modeling. In this report, the lower-length-scale efforts in method and material model development supported by the Accident Tolerance Fuel (ATF) high-impact-problem (HIP) under the NEAMS program are summarized. Significant progresses have been made regarding interatomic potential, phase field models for phase decomposition and gas bubble formation, and thermal conductivity for U3Si2 fuel, and precipitation in FeCrAl cladding. The accomplishments are very useful by providing atomistic and mesoscale tools, improving the current understanding, and delivering engineering scale models for these two ATF concepts.

  13. Affinities of bispyridinium non-oxime compounds to [(3)H]epibatidine binding sites of Torpedo californica nicotinic acetylcholine receptors depend on linker length.

    Science.gov (United States)

    Niessen, K V; Seeger, T; Tattersall, J E H; Timperley, C M; Bird, M; Green, C; Thiermann, H; Worek, F

    2013-12-05

    The toxicity of organophosphorus nerve agents or pesticides arises from accumulation of acetylcholine and overstimulation of both muscarinic and nicotinic acetylcholine receptors (mAChRs and nAChRs) due to inhibition of acetylcholinesterase (AChE). Standard treatment by administration of atropine and oximes, e.g., obidoxime or pralidoxime, focuses on antagonism of mAChRs and reactivation of AChE, whereas nicotinic malfunction is not directly treated. An alternative approach would be to use nAChR active substances to counteract the effects of accumulated acetylcholine. Promising in vitro and in vivo results were obtained with the bispyridinium compounds SAD-128 (1,1'-oxydimethylene bis(4-tert-butylpyridinium) dichloride) and MB327 (1,1'-(propane-1,3-diyl)bis(4-tert-butylpyridinium) di(iodide)), which were partly attributed to their interaction with nAChRs. In this study, a homologous series of unsubstituted and 4-tert-butyl-substituted bispyridinium compounds with different alkane linker lengths was investigated in competition binding experiments using [(3)H]epibatidine as a reporter ligand. Additionally, the effect of the well-characterised MB327 on the [(3)H]epibatidine equilibrium dissociation (KD) constant in different buffers was determined. This study demonstrated that divalent cations increased the affinity of [(3)H]epibatidine. Since quaternary ammonium molecules are known to inhibit AChE, the obtained affinity constants of the tested bispyridinium compounds were compared with the inhibition of human AChE. In competition experiments, bispyridinium derivatives of longer linker length displaced [(3)H]epibatidine and inhibited AChE strongly. Bispyridinium compounds with short linkers, at most, have an allosteric interaction with the [(3)H]epibatidine binding sites and barely inhibited AChE. In dependence on alkane linker length, the bispyridinium compounds seemed to interact at different binding sites. However, the exact binding sites of the bispyridinium

  14. Vortex matter beyond SANS. Neutron studies of vortex structures covering a length scale of 0.01 ti 10 μm

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, Tommy

    2017-01-09

    This thesis is concerned with different generic types of vortex matter arising in the intermediate state of the type-I superconductor lead, the intermediate mixed state of the type-II superconductor niobium, and the helimagnetic phase of the compound manganese silicide. It is demonstrated and explained how a combination of i) the radiographic techniques neutron grating interferometry and neutron diffractive imaging with ii) scattering methods such as small-angle-neutron scattering and ultra-small-angle neutron scattering can provide novel insight into the bulk behavior of these vortex systems. By means of the used scattering methods, detailed information on the morphology of the vortex phases covering a length scale of 0.01 to 10 μm are obtained, while the radiographic approaches additionally map the spatial distribution of vortices within the sample. In particular, this thesis focuses on the strong influences of demagnetization, geometric barriers and pinning on the vortex configuration.

  15. The Extended Relativity Theory in Born-Clifford Phase Spaces with a Lower and Upper Length Scales and Clifford Group Geometric Unification

    CERN Document Server

    Castro, C

    2004-01-01

    We construct the Extended Relativity Theory in Born-Clifford-Phase spaces with an upper and lower length scales (infrared/ultraviolet cutoff). The invariance symmetry leads naturally to the real Clifford algebra Cl (2, 6, R ) and complexified Clifford Cl_C ( 4 ) algebra related to Twistors. We proceed with an extensive review of Smith's 8D model based on the Clifford algebra Cl ( 1 ,7) that reproduces at low energies the physics of the Standard Model and Gravity; including the derivation of all the coupling constants, particle masses, mixing angles, ....with high precision. Further results by Smith are discussed pertaining the interplay among Clifford, Jordan, Division and Exceptional Lie algebras within the hierarchy of dimensions D = 26, 27, 28 related to bosonic string, M, F theory. Two Geometric actions are presented like the Clifford-Space extension of Maxwell's Electrodynamics, Brandt's action related the 8D spacetime tangent-bundle involving coordinates and velocities (Finsler geometries) followed by a...

  16. Vortex matter beyond SANS. Neutron studies of vortex structures covering a length scale of 0.01 ti 10 μm

    International Nuclear Information System (INIS)

    Reimann, Tommy

    2017-01-01

    This thesis is concerned with different generic types of vortex matter arising in the intermediate state of the type-I superconductor lead, the intermediate mixed state of the type-II superconductor niobium, and the helimagnetic phase of the compound manganese silicide. It is demonstrated and explained how a combination of i) the radiographic techniques neutron grating interferometry and neutron diffractive imaging with ii) scattering methods such as small-angle-neutron scattering and ultra-small-angle neutron scattering can provide novel insight into the bulk behavior of these vortex systems. By means of the used scattering methods, detailed information on the morphology of the vortex phases covering a length scale of 0.01 to 10 μm are obtained, while the radiographic approaches additionally map the spatial distribution of vortices within the sample. In particular, this thesis focuses on the strong influences of demagnetization, geometric barriers and pinning on the vortex configuration.

  17. Scale dependence of canopy trait distributions along a tropical forest elevation gradient.

    Science.gov (United States)

    Asner, Gregory P; Martin, Roberta E; Anderson, Christopher B; Kryston, Katherine; Vaughn, Nicholas; Knapp, David E; Bentley, Lisa Patrick; Shenkin, Alexander; Salinas, Norma; Sinca, Felipe; Tupayachi, Raul; Quispe Huaypar, Katherine; Montoya Pillco, Milenka; Ccori Álvarez, Flor Delis; Díaz, Sandra; Enquist, Brian J; Malhi, Yadvinder

    2017-05-01

    Average responses of forest foliar traits to elevation are well understood, but far less is known about trait distributional responses to elevation at multiple ecological scales. This limits our understanding of the ecological scales at which trait variation occurs in response to environmental drivers and change. We analyzed and compared multiple canopy foliar trait distributions using field sampling and airborne imaging spectroscopy along an Andes-to-Amazon elevation gradient. Field-estimated traits were generated from three community-weighting methods, and remotely sensed estimates of traits were made at three scales defined by sampling grain size and ecological extent. Field and remote sensing approaches revealed increases in average leaf mass per unit area (LMA), water, nonstructural carbohydrates (NSCs) and polyphenols with increasing elevation. Foliar nutrients and photosynthetic pigments displayed little to no elevation trend. Sample weighting approaches had little impact on field-estimated trait responses to elevation. Plot representativeness of trait distributions at landscape scales decreased with increasing elevation. Remote sensing indicated elevation-dependent increases in trait variance and distributional skew. Multiscale invariance of LMA, leaf water and NSC mark these traits as candidates for tracking forest responses to changing climate. Trait-based ecological studies can be greatly enhanced with multiscale studies made possible by imaging spectroscopy. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  18. The scale-dependent market trend: Empirical evidences using the lagged DFA method

    Science.gov (United States)

    Li, Daye; Kou, Zhun; Sun, Qiankun

    2015-09-01

    In this paper we make an empirical research and test the efficiency of 44 important market indexes in multiple scales. A modified method based on the lagged detrended fluctuation analysis is utilized to maximize the information of long-term correlations from the non-zero lags and keep the margin of errors small when measuring the local Hurst exponent. Our empirical result illustrates that a common pattern can be found in the majority of the measured market indexes which tend to be persistent (with the local Hurst exponent > 0.5) in the small time scale, whereas it displays significant anti-persistent characteristics in large time scales. Moreover, not only the stock markets but also the foreign exchange markets share this pattern. Considering that the exchange markets are only weakly synchronized with the economic cycles, it can be concluded that the economic cycles can cause anti-persistence in the large time scale but there are also other factors at work. The empirical result supports the view that financial markets are multi-fractal and it indicates that deviations from efficiency and the type of model to describe the trend of market price are dependent on the forecasting horizon.

  19. A bodyweight-dependent allometric exponent for scaling clearance across the human life-span.

    Science.gov (United States)

    Wang, Chenguang; Peeters, Mariska Y M; Allegaert, Karel; Blussé van Oud-Alblas, Heleen J; Krekels, Elke H J; Tibboel, Dick; Danhof, Meindert; Knibbe, Catherijne A J

    2012-06-01

    To explore different allometric equations for scaling clearance across the human life-span using propofol as a model drug. Data from seven previously published propofol studies ((pre)term neonates, infants, toddlers, children, adolescents and adults) were analysed using NONMEM VI. To scale clearance, a bodyweight-based exponential equation with four different structures for the exponent was used: (I) 3/4 allometric scaling model; (II) mixture model; (III) bodyweight-cut-point separated model; (IV) bodyweight-dependent exponent model. Model I adequately described clearance in adults and older children, but overestimated clearance of neonates and underestimated clearance of infants. Use of two different exponents in Model II and Model III showed significantly improved performance, but yielded ambiguities on the boundaries of the two subpopulations. This discontinuity was overcome in Model IV, in which the exponent changed sigmoidally from 1.35 at a hypothetical bodyweight of 0 kg to a value of 0.56 from 10 kg onwards, thereby describing clearance of all individuals best. A model was developed for scaling clearance over the entire human life-span with a single continuous equation, in which the exponent of the bodyweight-based exponential equation varied with bodyweight.

  20. Temperature and saturation dependence in the vapor sensing of butterfly wing scales

    Energy Technology Data Exchange (ETDEWEB)

    Kertész, K., E-mail: kertesz.krisztian@ttk.mta.hu [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49 (Hungary); Piszter, G. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49 (Hungary); Jakab, E. [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, H-1525 Budapest, P O Box 17 (Hungary); Bálint, Zs. [Hungarian Natural History Museum, H-1088, Budapest, Baross utca 13 (Hungary); Vértesy, Z.; Biró, L.P. [Institute of Technical Physics and Materials Science, Research Centre for Natural Sciences, 1525 Budapest, PO Box 49 (Hungary)

    2014-06-01

    The sensing of gasses/vapors in the ambient air is the focus of attention due to the need to monitor our everyday environment. Photonic crystals are sensing materials of the future because of their strong light-manipulating properties. Natural photonic structures are well-suited materials for testing detection principles because they are significantly cheaper than artificial photonic structures and are available in larger sizes. Additionally, natural photonic structures may provide new ideas for developing novel artificial photonic nanoarchitectures with improved properties. In the present paper, we discuss the effects arising from the sensor temperature and the vapor concentration in air during measurements with a photonic crystal-type optical gas sensor. Our results shed light on the sources of discrepancy between simulated and experimental sensing behaviors of photonic crystal-type structures. Through capillary condensation, the vapors will condensate to a liquid state inside the nanocavities. Due to the temperature and radius of curvature dependence of capillary condensation, the measured signals are affected by the sensor temperature as well as by the presence of a nanocavity size distribution. The sensing materials used are natural photonic nanoarchitectures present in the wing scales of blue butterflies. - Highlights: • We report optical gas sensing on blue butterfly wing scale nanostructures. • The sample temperature decrease effects a reversible break-down in the measured spectra. • The break-down is connected with the vapor condensation in the scales and wing surface. • Capillary condensation occurs in the wing scales.

  1. The viscoelastic properties of chromatin and the nucleoplasm revealed by scale-dependent protein mobility

    Science.gov (United States)

    Erdel, Fabian; Baum, Michael; Rippe, Karsten

    2015-02-01

    The eukaryotic cell nucleus harbours the DNA genome that is organized in a dynamic chromatin network and embedded in a viscous crowded fluid. This environment directly affects enzymatic reactions and target search processes that access the DNA sequence information. However, its physical properties as a reaction medium are poorly understood. Here, we exploit mobility measurements of differently sized inert green fluorescent tracer proteins to characterize the viscoelastic properties of the nuclear interior of a living human cell. We find that it resembles a viscous fluid on small and large scales but appears viscoelastic on intermediate scales that change with protein size. Our results are consistent with simulations of diffusion through polymers and suggest that chromatin forms a random obstacle network rather than a self-similar structure with fixed fractal dimensions. By calculating how long molecules remember their previous position in dependence on their size, we evaluate how the nuclear environment affects search processes of chromatin targets.

  2. Scale dependence in habitat selection: The case of the endangered brown bear (Ursus arctos) in the Cantabrian Range (NW Spain)

    Science.gov (United States)

    Maria C. Mateo Sanchez; Samuel A. Cushman; Santiago Saura

    2013-01-01

    Animals select habitat resources at multiple spatial scales. Thus, explicit attention to scale dependency in species-habitat relationships is critical to understand the habitat suitability patterns as perceived by organisms in complex landscapes. Identification of the scales at which particular environmental variables influence habitat selection may be as important as...

  3. Testing feasibility of scalar-tensor gravity by scale dependent mass and coupling to matter

    OpenAIRE

    Mota, D. F.; Salzano, V.; Capozziello, S.

    2011-01-01

    We investigate whether there is any cosmological evidence for a scalar field with a mass and coupling to matter which change accordingly to the properties of the astrophysical system it “lives in,” without directly focusing on the underlying mechanism that drives the scalar field scale-dependent-properties. We assume a Yukawa type of coupling between the field and matter and also that the scalar-field mass grows with density, in order to overcome all gravity constraints within the Solar Syste...

  4. Scale-Dependent Fracture-Matrix Interactions And Their Impact on Radionuclide Transport - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Detwiler, Russell

    2014-06-30

    Matrix diffusion and adsorption within a rock matrix are widely regarded as important mechanisms for retarding the transport of radionuclides and other solutes in fractured rock (e.g., Neretnieks, 1980; Tang et al., 1981; Maloszewski and Zuber, 1985; Novakowski and Lapcevic, 1994; Jardine et al., 1999; Zhou and Xie, 2003; Reimus et al., 2003a,b). When remediation options are being evaluated for old sources of contamination, where a large fraction of contaminants reside within the rock matrix, slow diffusion out of the matrix greatly increases the difficulty and timeframe of remediation. Estimating the rates of solute exchange between fractures and the adjacent rock matrix is a critical factor in quantifying immobilization and/or remobilization of DOE-relevant contaminants within the subsurface. In principle, the most rigorous approach to modeling solute transport with fracture-matrix interaction would be based on local-scale coupled advection-diffusion/dispersion equations for the rock matrix and in discrete fractures that comprise the fracture network (Discrete Fracture Network and Matrix approach, hereinafter referred to as DFNM approach), fully resolving aperture variability in fractures and matrix property heterogeneity. However, such approaches are computationally demanding, and thus, many predictive models rely upon simplified models. These models typically idealize fracture rock masses as a single fracture or system of parallel fractures interacting with slabs of porous matrix or as a mobile-immobile or multi-rate mass transfer system. These idealizations provide tractable approaches for interpreting tracer tests and predicting contaminant mobility, but rely upon a fitted effective matrix diffusivity or mass-transfer coefficients. However, because these fitted parameters are based upon simplified conceptual models, their effectiveness at predicting long-term transport processes remains uncertain. Evidence of scale dependence of effective matrix diffusion

  5. A space and time scale-dependent nonlinear geostatistical approach for downscaling daily precipitation and temperature

    KAUST Repository

    Jha, Sanjeev Kumar

    2015-07-21

    A geostatistical framework is proposed to downscale daily precipitation and temperature. The methodology is based on multiple-point geostatistics (MPS), where a multivariate training image is used to represent the spatial relationship between daily precipitation and daily temperature over several years. Here, the training image consists of daily rainfall and temperature outputs from the Weather Research and Forecasting (WRF) model at 50 km and 10 km resolution for a twenty year period ranging from 1985 to 2004. The data are used to predict downscaled climate variables for the year 2005. The result, for each downscaled pixel, is daily time series of precipitation and temperature that are spatially dependent. Comparison of predicted precipitation and temperature against a reference dataset indicates that both the seasonal average climate response together with the temporal variability are well reproduced. The explicit inclusion of time dependence is explored by considering the climate properties of the previous day as an additional variable. Comparison of simulations with and without inclusion of time dependence shows that the temporal dependence only slightly improves the daily prediction because the temporal variability is already well represented in the conditioning data. Overall, the study shows that the multiple-point geostatistics approach is an efficient tool to be used for statistical downscaling to obtain local scale estimates of precipitation and temperature from General Circulation Models. This article is protected by copyright. All rights reserved.

  6. Fundamental length and relativistic length

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1988-01-01

    It si noted that the introduction of fundamental length contradicts the conventional representations concerning the contraction of the longitudinal size of fast-moving objects. The use of the concept of relativistic length and the following ''elongation formula'' permits one to solve this problem

  7. Combination of Complement-Dependent Cytotoxicity and Relative Fluorescent Quantification of HLA Length Polymorphisms Facilitates the Detection of a Loss of Heterozygosity

    Directory of Open Access Journals (Sweden)

    Klaus Witter

    2014-01-01

    Full Text Available Loss of heterozygosity (LOH is a common event in malignant cells. In this work we introduce a new approach to identify patients with loss of heterozygosity in the HLA region either at first diagnosis or after HLA mismatched allogeneic HSCT. Diagnosis of LOH requires a high purity of recipient target cells. FACS is time consuming and also frequently prevented by rather nonspecific or unknown immune phenotype. The approach for recipient cell enrichment is based on HLA targeted complement-dependent cytotoxicity (CDC. Relative fluorescent quantification (RFQ analysis of HLA intron length polymorphisms then allows analysis of HLA heterozygosity. The approach is exemplified in recent clinical cases illustrating the detection of an acquired allele loss. As illustrated in one case with DPB1, distinct HLA loci in donor and patient were sufficient for both proof of donor cell removal and evaluation of allele loss in the patient's leukemic cells. Results were confirmed using HLA-B RFQ analysis and leukemia-associated aberrant immunophenotype (LAIP based cell sort. Both results confirmed suspected loss of HLA heterozygosity. Our approach complements or substitutes for FACS-based cell enrichment; hence it may be further developed as novel routine diagnostic tool. This allows rapid recipient cell purification and testing for loss of HLA heterozygosity before and after allogeneic HSCT in easily accessible peripheral blood samples.

  8. Dependence of the absorption of pulsed CO2-laser radiation by silane on wavenumber, fluence, pulse duration, temperature, optical path length, and pressure of absorbing and nonabsorbing gases

    International Nuclear Information System (INIS)

    Blazejowski, J.; Gruzdiewa, L.; Rulewski, J.; Lampe, F.W.

    1995-01-01

    The absorption of three lines [P(20), 944.2 cm -1 ; P(14), 949.2 cm -1 ; and R(24), 978.5 cm -1 ] of the pulsed CO 2 laser (00 0 1--10 0 0 transition) by SiH 4 was measured at various pulse energy, pulse duration, temperature, optical path length, and pressure of the compound and nonabsorbing foreign gases. In addition, low intensity infrared absorption spectrum of silane was compared with high intensity absorption characteristics for all lines of the pulsed CO 2 laser. The experimental dependencies show deviations from the phenomenological Beer--Lambert law which can be considered as arising from the high intensity of an incident radiation and collisions of absorbing molecules with surroundings. These effects were included into the expression, being an extended form of the Beer--Lambert law, which reasonably approximates all experimental data. The results, except for extending knowledge on the interaction of a high power laser radiation with matter, can help understanding and planning processes leading to preparation of silicon-containing technologically important materials

  9. Excitation-Dependent Carrier lifetime and Diffusion Length in Bulk CdTe Determined by Time-Resolved Optical Pump-Probe Techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Kuciauskas, Darius [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Scajev, Patrik [Vilnius University; Miasojedovas, Saulius [Vilnius University; Mekys, Algirdas [Vilnius University; Lynn, Kelvin G. [Washington State University; Swain, Santosh K. [Washington State University; Jarasiunas, Kestutis [Vilnius University

    2018-01-11

    We applied time-resolved pump-probe spectroscopy based on free carrier absorption and light diffraction on a transient grating for direct measurements of the carrier lifetime and diffusion coefficient D in high-resistivity single crystal CdTe (codoped with In and Er). The bulk carrier lifetime t decreased from 670 +/-50 ns to 60 +/- 10 ns with increase of excess carrier density N from 10^16 to 5 x 10^18 cm-3 due to the excitation-dependent radiative recombination rate. In this N range, the carrier diffusion length dropped from 14 um to 6 um due to lifetime decrease. Modeling of in-depth (axial) and in-plane (lateral) carrier diffusion provided the value of surface recombination velocity S = 6 x 10^5 cm/s for the untreated surface. At even higher excitations, in the 10^19-3 x 10^20 cm-3 density range, D increase from 5 to 20 cm^2/s due to carrier degeneracy was observed.

  10. Power law scaling in synchronization of brain signals depends on cognitive load.

    Science.gov (United States)

    Tinker, Jesse; Velazquez, Jose Luis Perez

    2014-01-01

    As it has several features that optimize information processing, it has been proposed that criticality governs the dynamics of nervous system activity. Indications of such dynamics have been reported for a variety of in vitro and in vivo recordings, ranging from in vitro slice electrophysiology to human functional magnetic resonance imaging. However, there still remains considerable debate as to whether the brain actually operates close to criticality or in another governing state such as stochastic or oscillatory dynamics. A tool used to investigate the criticality of nervous system data is the inspection of power-law distributions. Although the findings are controversial, such power-law scaling has been found in different types of recordings. Here, we studied whether there is a power law scaling in the distribution of the phase synchronization derived from magnetoencephalographic recordings during executive function tasks performed by children with and without autism. Characterizing the brain dynamics that is different between autistic and non-autistic individuals is important in order to find differences that could either aid diagnosis or provide insights as to possible therapeutic interventions in autism. We report in this study that power law scaling in the distributions of a phase synchrony index is not very common and its frequency of occurrence is similar in the control and the autism group. In addition, power law scaling tends to diminish with increased cognitive load (difficulty or engagement in the task). There were indications of changes in the probability distribution functions for the phase synchrony that were associated with a transition from power law scaling to lack of power law (or vice versa), which suggests the presence of phenomenological bifurcations in brain dynamics associated with cognitive load. Hence, brain dynamics may fluctuate between criticality and other regimes depending upon context and behaviors.

  11. Power law scaling in synchronization of brain signals depends on cognitive load

    Directory of Open Access Journals (Sweden)

    Jose Luis ePerez Velazquez

    2014-05-01

    Full Text Available As it has several features that optimize information processing, it has been proposed that criticality governs the dynamics of nervous system activity. Indications of such dynamics have been reported for a variety of in vitro and in vivo recordings, ranging from in vitro slice electrophysiology to human functional magnetic resonance imaging. However, there still remains considerable debate as to whether the brain actually operates close to criticality or in another governing state such as stochastic or oscillatory dynamics. A tool used to investigate the criticality of nervous system data is the inspection of power-law distributions. Although the findings are controversial, such power-law scaling has been found in different types of recordings. Here, we studied whether there is a power law scaling in the distribution of the phase synchronization derived from magnetoencephalographic recordings during executive function tasks performed by children with and without autism. Characterizing the brain dynamics that is different between autistic and non-autistic individuals is important in order to find differences that could either aid diagnosis or provide insights as to possible therapeutic interventions in autism. We report in this study that power law scaling in the distributions of a phase synchrony index is not very common and its frequency of occurrence is similar in the control and the autism group. In addition, power law scaling tends to diminish with increased cognitive load (difficulty or engagement in the task. There were indications of changes in the probability distribution functions for the phase synchrony that were associated with a transition from power law scaling to lack of power law (or vice versa, which suggests the presence of phenomenological bifurcations in brain dynamics associated with cognitive load. Hence, brain dynamics may fluctuate between criticality and other regimes depending upon context and behaviours.

  12. Flame Length

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  13. Predictors of extended length of stay, discharge to inpatient rehab, and hospital readmission following elective lumbar spine surgery: introduction of the Carolina-Semmes Grading Scale.

    Science.gov (United States)

    McGirt, Matthew J; Parker, Scott L; Chotai, Silky; Pfortmiller, Deborah; Sorenson, Jeffrey M; Foley, Kevin; Asher, Anthony L

    2017-10-01

    OBJECTIVE Extended hospital length of stay (LOS), unplanned hospital readmission, and need for inpatient rehabilitation after elective spine surgery contribute significantly to the variation in surgical health care costs. As novel payment models shift the risk of cost overruns from payers to providers, understanding patient-level risk of LOS, readmission, and inpatient rehabilitation is critical. The authors set out to develop a grading scale that effectively stratifies risk of these costly events after elective surgery for degenerative lumbar pathologies. METHODS The Quality and Outcomes Database (QOD) registry prospectively enrolls patients undergoing surgery for degenerative lumbar spine disease. This registry was queried for patients who had undergone elective 1- to 3-level lumbar surgery for degenerative spine pathology. The association between preoperative patient variables and extended postoperative hospital LOS (LOS ≥ 7 days), discharge status (inpatient facility vs home), and 90-day hospital readmission was assessed using stepwise multivariate logistic regression. The Carolina-Semmes grading scale was constructed using the independent predictors for LOS (0-12 points), discharge to inpatient facility (0-18 points), and 90-day readmission (0-6 points), and its performance was assessed using the QOD data set. The performance of the grading scale was then confirmed separately after using it in 2 separate neurosurgery practice sites (Carolina Neurosurgery & Spine Associates [CNSA] and Semmes Murphey Clinic). RESULTS A total of 6921 patients were analyzed. Overall, 290 (4.2%) patients required extended LOS, 654 (9.4%) required inpatient facility care/rehabilitation on hospital discharge, and 474 (6.8%) were readmitted to the hospital within 90 days postdischarge. Variables that remained as independently associated with these unplanned events in multivariate analysis included age ≥ 70 years, American Society of Anesthesiologists Physical Classification System

  14. Scale-dependent galaxy bias from massive particles with spin during inflation

    Science.gov (United States)

    Moradinezhad Dizgah, Azadeh; Dvorkin, Cora

    2018-01-01

    The presence of additional particles during inflation leads to non-Gaussianity in late-time correlators of primordial curvature perturbations. The shape and amplitude of this signal depend on the mass and spin of the extra particles. Constraints on this distinct form of primordial non-Gaussianity, therefore, provide a wealth of information on the particle content during inflation. We investigate the potential of upcoming galaxy surveys in constraining such a signature through its impact on the observed galaxy power spectrum. Primordial non-Gaussianity of various shapes induces a scale-dependent bias on tracers of large-scale structure, such as galaxies. Using this signature we obtain constraints on massive particles during inflation, which can have non-zero spins. In particular, we show that the prospects for constraining particles with spins 0 and 1 are promising, while constraining particles with spin 2 from power spectrum alone seems challenging. We show that the multi-tracer technique can significantly improve the constraints from the power spectrum by at least an order of magnitude. Furthermore, we analyze the effect of non-linearities due to gravitational evolution on the forecasted constraints on the masses of the extra particles and the amplitudes of the imprinted non-Gaussian signal. We find that gravitational evolution affects the constraints by less than a factor of 2.

  15. Testing feasibility of scalar-tensor gravity by scale dependent mass and coupling to matter

    International Nuclear Information System (INIS)

    Mota, D. F.; Salzano, V.; Capozziello, S.

    2011-01-01

    We investigate whether there is any cosmological evidence for a scalar field with a mass and coupling to matter which change accordingly to the properties of the astrophysical system it ''lives in,'' without directly focusing on the underlying mechanism that drives the scalar field scale-dependent-properties. We assume a Yukawa type of coupling between the field and matter and also that the scalar-field mass grows with density, in order to overcome all gravity constraints within the Solar System. We analyze three different gravitational systems assumed as ''cosmological indicators'': supernovae type Ia, low surface brightness spiral galaxies and clusters of galaxies. Results show (i) a quite good fit to the rotation curves of low surface brightness galaxies only using visible stellar and gas-mass components is obtained; (ii) a scalar field can fairly well reproduce the matter profile in clusters of galaxies, estimated by x-ray observations and without the need of any additional dark matter; and (iii) there is an intrinsic difficulty in extracting information about the possibility of a scale-dependent massive scalar field (or more generally about a varying gravitational constant) from supernovae type Ia.

  16. Charge Separation in Intermixed Polymer:PC70BM Photovoltaic Blends: Correlating Structural and Photophysical Length Scales as a Function of Blend Composition

    KAUST Repository

    Utzat, Hendrik

    2017-04-24

    A key challenge in achieving control over photocurrent generation by bulk-heterojunction organic solar cells is understanding how the morphology of the active layer impacts charge separation and in particular the separation dynamics within molecularly intermixed donor-acceptor domains versus the dynamics between phase-segregated domains. This paper addresses this issue by studying blends and devices of the amorphous silicon-indacenodithiophene polymer SiIDT-DTBT and the acceptor PCBM. By changing the blend composition, we modulate the size and density of the pure and intermixed domains on the nanometer length scale. Laser spectroscopic studies show that these changes in morphology correlate quantitatively with the changes in charge separation dynamics on the nanosecond time scale and with device photocurrent densities. At low fullerene compositions, where only a single, molecularly intermixed polymer-fullerene phase is observed, photoexcitation results in a ∼ 30% charge loss from geminate polaron pair recombination, which is further studied via light intensity experiments showing that the radius of the polaron pairs in the intermixed phase is 3-5 nm. At high fullerene compositions (≥67%), where the intermixed domains are 1-3 nm and the pure fullerene phases reach ∼4 nm, the geminate recombination is suppressed by the reduction of the intermixed phase, making the fullerene domains accessible for electron escape.

  17. A study of small-scale foliation in lengths of core enclosing fault zones in borehole WD-3, Permit Area D, Lac du Bonnet Batholith

    Energy Technology Data Exchange (ETDEWEB)

    Ejeckam, R.B.

    1992-12-01

    Small-scale foliation measurements in lengths of core from borehole WD-3 of Permit Area D of the Lac du Bonnet Batholith have defined five major mean orientation sets. They strike NW, N and NE. The orientations (strike to the left of the dip direction/dip) of these sets are as follows: Set I - 028/74 deg; II - 001/66 deg; III - 100/58 deg; IV - 076/83 deg; and V - 210/40 deg. The small-scale foliations were defined by different mineral types such as biotite crystals, plagioclase, mineral banding and quartz lenses. Well-developed biotite foliation is commonly present whenever well-developed plagioclase foliation exists, but as the strength of development weakens, the preferred orientations of plagioclase foliation do not correspond to those of biotite. It is also noted that the foliations appear to strike in directions orthogonal to the fractures in the fracture zones in the same depth interval. No significant change in foliation orientation was observed in Zones I to IV. Set V, however, whose mean orientation is 210/40 deg, is absent from the Zone IV interval, ranging from 872 to 905 m. (auth)

  18. A multi scale approximation solution for the time dependent Boltzmann-transport equation

    International Nuclear Information System (INIS)

    Merk, B.

    2004-03-01

    The basis of all transient simulations for nuclear reactor cores is the reliable calculation of the power production. The local power distribution is generally calculated by solving the space, time, energy and angle dependent neutron transport equation known as Boltzmann equation. The computation of exact solutions of the Boltzmann equation is very time consuming. For practical numerical simulations approximated solutions are usually unavoidable. The objective of this work is development of an effective multi scale approximation solution for the Boltzmann equation. Most of the existing methods are based on separation of space and time. The new suggested method is performed without space-time separation. This effective approximation solution is developed on the basis of an expansion for the time derivative of different approximations to the Boltzmann equation. The method of multiple scale expansion is used for the expansion of the time derivative, because the problem of the stiff time behaviour can't be expressed by standard expansion methods. This multiple scale expansion is used in this work to develop approximation solutions for different approximations of the Boltzmann equation, starting from the expansion of the point kinetics equations. The resulting analytic functions are used for testing the applicability and accuracy of the multiple scale expansion method for an approximation solution with 2 delayed neutron groups. The results are tested versus the exact analytical results for the point kinetics equations. Very good agreement between both solutions is obtained. The validity of the solution with 2 delayed neutron groups to approximate the behaviour of the system with 6 delayed neutron groups is demonstrated in an additional analysis. A strategy for a solution with 4 delayed neutron groups is described. A multiple scale expansion is performed for the space-time dependent diffusion equation for one homogenized cell with 2 delayed neutron groups. The result is

  19. Scale-dependent diversity patterns affect spider assemblages of two contrasting forest ecosystems

    Science.gov (United States)

    Schuldt, Andreas; Assmann, Thorsten; Schaefer, Matthias

    2013-05-01

    Spiders are important generalist predators in forests. However, differences in assemblage structure and diversity can have consequences for their functional impact. Such differences are particularly evident across latitudes, and their analysis can help to generate a better understanding of region-specific characteristics of predator assemblages. Here, we analyse the relationships between species richness, family richness and functional diversity (FD) as well as α- and β-components of epigeic spider diversity in semi-natural temperate and subtropical forest sites. As expected, within-plot and overall spider species and family richness were higher in the subtropical plots. In contrast, local FD within plots was similar between sites, and differences in FD only became evident at larger spatial scales due to higher species turnover in the subtropical forests. Our study indicates that the functional effects of predator assemblages can change across spatial scales. We discuss how differences in richness and functional diversity between contrasting forest ecosystems can depend on environmental heterogeneity and the effects of species filters acting at local scales. The high turnover observed in the species-rich subtropical forests also requires a more regional perspective for the conservation of the overall diversity and the ecological functions of predators than in less diverse forests, as strategies need to account for the large spatial heterogeneity among plots.

  20. Alignments of Dark Matter Halos with Large-scale Tidal Fields: Mass and Redshift Dependence

    Science.gov (United States)

    Chen, Sijie; Wang, Huiyuan; Mo, H. J.; Shi, Jingjing

    2016-07-01

    Large-scale tidal fields estimated directly from the distribution of dark matter halos are used to investigate how halo shapes and spin vectors are aligned with the cosmic web. The major, intermediate, and minor axes of halos are aligned with the corresponding tidal axes, and halo spin axes tend to be parallel with the intermediate axes and perpendicular to the major axes of the tidal field. The strengths of these alignments generally increase with halo mass and redshift, but the dependence is only on the peak height, ν \\equiv {δ }{{c}}/σ ({M}{{h}},z). The scaling relations of the alignment strengths with the value of ν indicate that the alignment strengths remain roughly constant when the structures within which the halos reside are still in a quasi-linear regime, but decreases as nonlinear evolution becomes more important. We also calculate the alignments in projection so that our results can be compared directly with observations. Finally, we investigate the alignments of tidal tensors on large scales, and use the results to understand alignments of halo pairs separated at various distances. Our results suggest that the coherent structure of the tidal field is the underlying reason for the alignments of halos and galaxies seen in numerical simulations and in observations.

  1. Psychometric properties of the Barratt Impulsiveness Scale in patients with gambling disorders, hypersexuality, and methamphetamine dependence.

    Science.gov (United States)

    Reid, Rory C; Cyders, Melissa A; Moghaddam, Jacquelene F; Fong, Timothy W

    2014-11-01

    Although the Barratt Impulsiveness Scale (BIS; Patton, Stanford, & Barratt, 1995) is a widely-used self-report measure of impulsivity, there have been numerous questions about the invariance of the factor structure across clinical populations (Haden & Shiva, 2008, 2009; Ireland & Archer, 2008). The goal of this article is to examine the factor structure of the BIS among a sample consisting of three populations exhibiting addictive behaviors and impulsivity: pathological gamblers, hypersexual patients, and individuals seeking treatment for methamphetamine dependence to determine if modification to the existing factors might improve the psychometric properties of the BIS. The current study found that the factor structure of the BIS does not replicate in this sample and instead produces a 12-item three-factor solution consisting of motor-impulsiveness (5 items), non-planning impulsiveness (3 items), and immediacy impulsiveness (4 items). The clinical utility of the BIS in this population is questionable. The authors suggest future studies to investigate comparisons with this modified version of the BIS and other impulsivity scales such as the UPPS-P Impulsive Behavior Scale in clinical populations when assessing disposition toward rash action. Copyright © 2013. Published by Elsevier Ltd.

  2. Long length scales of element transport during reaction texture development in orthoamphibole-cordierite gneiss: Thor-Odin dome, British Columbia, Canada

    Science.gov (United States)

    Goergen, Eric T.; Whitney, Donna L.

    2012-02-01

    First-order factors controlling the textural and chemical evolution of metamorphic rocks are bulk composition and pressure-temperature-time ( P- T- t) path. Although it is common to assume that major element bulk composition does not change during regional metamorphism, rocks with reaction textures such as corona structures record evidence for major changes in effective bulk composition (EBC) and therefore provide significant insight into the scale, pathways, and mechanisms of element transport during metamorphism. Quantifying changes in EBC is essential for petrologic applications such as calculation of phase diagrams (pseudosections). The progressive growth of complex corona structures on garnet and Al2SiO5 porphyroblasts in orthoamphibole-cordierite gneiss Thor-Odin dome (British Columbia, Canada) reduced the EBC volume of the rock during metamorphism and therefore had a dramatic effect on the evolution of the stable mineral assemblage. These rocks contain a chemical and textural record of metamorphic reactions and preserve 3D networks (reaction pathways) connecting corona structures. These coronal networks record long (>cm) length scales of localized element transport during metamorphism. P- T, T- X, and P- X pseudosections are used to investigate the control of effective bulk composition on phase assemblage evolution. Despite textural complexity and evidence for disequilibrium, mineral assemblages and compositions were successfully modeled and peak metamorphic conditions estimated at 750°C and 9 kbar. These results illustrate how textural and chemical changes during metamorphism can be evaluated using an integrated petrographic and pseudosection approach, highlight the importance of effective bulk composition choice for application of phase equilibria methods in metamorphic rocks, and show how corona structures can be used to understand the scale of compositional change and element transport during metamorphism.

  3. Controls on topographic dependence and temporal instability in catchment-scale soil moisture patterns

    Science.gov (United States)

    Coleman, Michael L.; Niemann, Jeffrey D.

    2013-03-01

    At the catchment scale, soil moisture patterns have been observed to exhibit different types of dependence on topography. Some catchments have their wettest locations in the valley bottoms, while others have their wettest locations on hillslopes that are oriented away from the sun. Additionally, some catchments have soil moisture patterns that maintain a similar organization at all times (temporal stability), while other catchments have soil moisture patterns that change through time (temporal instability). Although these tendencies are well known, the reasons for their occurrence at a particular catchment are not well understood. In this paper, we investigate conditions under which different types of topographic dependence and different degrees of temporal instability can occur through the use of a new conceptual model. The type of topographic dependence and the degree of instability are quantified by two metrics that are also introduced in the paper, and the effects of soil, vegetation, and climatic parameters on these metrics are then evaluated. The evaluations indicate that saturated horizontal hydraulic conductivity, pore disconnectedness, and a vegetation evapotranspiration efficiency parameter have strong effects on the organization and instability of the soil moisture patterns. In contrast, annual potential evapotranspiration alone has less impact on the organization or its stability.

  4. Validation of the nicotine dependence syndrome scale (NDSS): a criterion-group design contrasting chippers and regular smokers

    OpenAIRE

    Shiffman, Saul; Sayette, Michael A.

    2005-01-01

    The nicotine dependence syndrome scale (NDSS) is a new multi-dimensional measure of nicotine dependence, yielding five scores for different aspects of dependence as well as a total score. In this study, we tested the NDSS in a young adult sample (mean age = 24), using an extreme-groups comparison between non-dependent smokers (chippers, n = 123) and regular smokers (n = 130). Scores on each NDSS subscale strongly discriminated between the groups, with the NDSS-total discriminating them almost...

  5. Tapasin facilitation of natural HLA-A and -B allomorphs is strongly influenced by peptide length, depends on stability, and separates closely related allomorphs

    DEFF Research Database (Denmark)

    Geironson, Linda; Thuring, Camilla; Harndahl, Mikkel

    2013-01-01

    Despite an abundance of peptides inside a cell, only a small fraction is ultimately presented by HLA-I on the cell surface. The presented peptides have HLA-I allomorph-specific motifs and are restricted in length. So far, detailed length studies have been limited to few allomorphs. Peptide-HLA-I ...

  6. Outer membrane protein X (Ail) contributes to Yersinia pestis virulence in pneumonic plague and its activity is dependent on the lipopolysaccharide core length.

    Science.gov (United States)

    Kolodziejek, Anna M; Schnider, Darren R; Rohde, Harold N; Wojtowicz, Andrzej J; Bohach, Gregory A; Minnich, Scott A; Hovde, Carolyn J

    2010-12-01

    Yersinia pestis, the causative agent of plague, is one of the most virulent microorganisms known. The outer membrane protein X (OmpX) in Y. pestis KIM is required for efficient bacterial adherence to and internalization by cultured HEp-2 cells and confers resistance to human serum. Here, we tested the contribution of OmpX to disease progression in the fully virulent Y. pestis CO92 strain by engineering a deletion mutant and comparing its ability in mediating pneumonic plague to that of the wild type in two animal models. The deletion of OmpX delayed the time to death up to 48 h in a mouse model and completely attenuated virulence in a rat model of disease. All rats challenged with 1 × 10(8) CFU of the ompX mutant survived, compared to the 50% lethal dose (LD50) of 1.2 × 10(3) CFU for the wild-type strain. Because murine serum is not bactericidal for the ompX mutant, the mechanism underlying the delay in time to death in mice was attributed to loss of adhesion/internalization properties but not serum resistance. The rat model, which is most similar to humans, highlighted the critical role of serum resistance in disease. To resolve conflicting evidence for the role of Y. pestis lipopolysaccharide (LPS) and OmpX in serum resistance, ompX was cloned into Escherichia coli D21 and three isogenic derivatives engineered to have progressively truncated LPS core saccharides. OmpX-mediated serum resistance, adhesiveness, and invasiveness, although dependent on LPS core length, displayed these functions in E. coli, independently of other Yersinia proteins and/or LPS. Also, autoaggregation was required for efficient OmpX-mediated adhesiveness and internalization but not serum resistance.

  7. Inulin-Type Fructans Modulates Pancreatic-Gut Innate Immune Responses and Gut Barrier Integrity during Experimental Acute Pancreatitis in a Chain Length-Dependent Manner.

    Science.gov (United States)

    He, Yue; Wu, Chengfei; Li, Jiahong; Li, Hongli; Sun, Zhenghua; Zhang, Hao; de Vos, Paul; Pan, Li-Long; Sun, Jia

    2017-01-01

    -light-chain-enhancer of activated B cells (NF-κB) p65 (p-NF-κB p65) nuclear translocation and activation in the pancreas. Our findings demonstrate a clear chain length-dependent effect of inulin on AP. The attenuating effects are caused by modulating effects of long-chain inulin on the pancreatic-gut immunity via the pancreatic IRAK-4/p-JNK/p-NF-κBp65 signaling pathway and on prevention of disruption of the gut barrier.

  8. Inulin-Type Fructans Modulates Pancreatic–Gut Innate Immune Responses and Gut Barrier Integrity during Experimental Acute Pancreatitis in a Chain Length-Dependent Manner

    Science.gov (United States)

    He, Yue; Wu, Chengfei; Li, Jiahong; Li, Hongli; Sun, Zhenghua; Zhang, Hao; de Vos, Paul; Pan, Li-Long; Sun, Jia

    2017-01-01

    -light-chain-enhancer of activated B cells (NF-κB) p65 (p-NF-κB p65) nuclear translocation and activation in the pancreas. Our findings demonstrate a clear chain length-dependent effect of inulin on AP. The attenuating effects are caused by modulating effects of long-chain inulin on the pancreatic–gut immunity via the pancreatic IRAK-4/p-JNK/p-NF-κBp65 signaling pathway and on prevention of disruption of the gut barrier. PMID:29018453

  9. Plant diversity increases with the strength of negative density dependence at the global scale.

    Science.gov (United States)

    LaManna, Joseph A; Mangan, Scott A; Alonso, Alfonso; Bourg, Norman A; Brockelman, Warren Y; Bunyavejchewin, Sarayudh; Chang, Li-Wan; Chiang, Jyh-Min; Chuyong, George B; Clay, Keith; Condit, Richard; Cordell, Susan; Davies, Stuart J; Furniss, Tucker J; Giardina, Christian P; Gunatilleke, I A U Nimal; Gunatilleke, C V Savitri; He, Fangliang; Howe, Robert W; Hubbell, Stephen P; Hsieh, Chang-Fu; Inman-Narahari, Faith M; Janík, David; Johnson, Daniel J; Kenfack, David; Korte, Lisa; Král, Kamil; Larson, Andrew J; Lutz, James A; McMahon, Sean M; McShea, William J; Memiaghe, Hervé R; Nathalang, Anuttara; Novotny, Vojtech; Ong, Perry S; Orwig, David A; Ostertag, Rebecca; Parker, Geoffrey G; Phillips, Richard P; Sack, Lawren; Sun, I-Fang; Tello, J Sebastián; Thomas, Duncan W; Turner, Benjamin L; Vela Díaz, Dilys M; Vrška, Tomáš; Weiblen, George D; Wolf, Amy; Yap, Sandra; Myers, Jonathan A

    2017-06-30

    Theory predicts that higher biodiversity in the tropics is maintained by specialized interactions among plants and their natural enemies that result in conspecific negative density dependence (CNDD). By using more than 3000 species and nearly 2.4 million trees across 24 forest plots worldwide, we show that global patterns in tree species diversity reflect not only stronger CNDD at tropical versus temperate latitudes but also a latitudinal shift in the relationship between CNDD and species abundance. CNDD was stronger for rare species at tropical versus temperate latitudes, potentially causing the persistence of greater numbers of rare species in the tropics. Our study reveals fundamental differences in the nature of local-scale biotic interactions that contribute to the maintenance of species diversity across temperate and tropical communities. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  10. Fundamental length

    International Nuclear Information System (INIS)

    Pradhan, T.

    1975-01-01

    The concept of fundamental length was first put forward by Heisenberg from purely dimensional reasons. From a study of the observed masses of the elementary particles known at that time, it is sumrised that this length should be of the order of magnitude 1 approximately 10 -13 cm. It was Heisenberg's belief that introduction of such a fundamental length would eliminate the divergence difficulties from relativistic quantum field theory by cutting off the high energy regions of the 'proper fields'. Since the divergence difficulties arise primarily due to infinite number of degrees of freedom, one simple remedy would be the introduction of a principle that limits these degrees of freedom by removing the effectiveness of the waves with a frequency exceeding a certain limit without destroying the relativistic invariance of the theory. The principle can be stated as follows: It is in principle impossible to invent an experiment of any kind that will permit a distintion between the positions of two particles at rest, the distance between which is below a certain limit. A more elegant way of introducing fundamental length into quantum theory is through commutation relations between two position operators. In quantum field theory such as quantum electrodynamics, it can be introduced through the commutation relation between two interpolating photon fields (vector potentials). (K.B.)

  11. Scale-dependent climatic drivers of human epidemics in ancient China.

    Science.gov (United States)

    Tian, Huidong; Yan, Chuan; Xu, Lei; Büntgen, Ulf; Stenseth, Nils C; Zhang, Zhibin

    2017-12-05

    A wide range of climate change-induced effects have been implicated in the prevalence of infectious diseases. Disentangling causes and consequences, however, remains particularly challenging at historical time scales, for which the quality and quantity of most of the available natural proxy archives and written documentary sources often decline. Here, we reconstruct the spatiotemporal occurrence patterns of human epidemics for large parts of China and most of the last two millennia. Cold and dry climate conditions indirectly increased the prevalence of epidemics through the influences of locusts and famines. Our results further reveal that low-frequency, long-term temperature trends mainly contributed to negative associations with epidemics, while positive associations of epidemics with droughts, floods, locusts, and famines mainly coincided with both higher and lower frequency temperature variations. Nevertheless, unstable relationships between human epidemics and temperature changes were observed on relatively smaller time scales. Our study suggests that an intertwined, direct, and indirect array of biological, ecological, and societal responses to different aspects of past climatic changes strongly depended on the frequency domain and study period chosen.

  12. Comparison of the responsiveness of the Care Dependency Scale for rehabilitation and the Barthel Index.

    Science.gov (United States)

    Eichhorn-Kissel, Juliane; Dassen, Theo; Lohrmann, Christa

    2011-08-01

    The aim of this study is to compare the responsiveness of the Care Dependency Scale for Rehabilitation (CDS-R) and the Barthel Index in rehabilitation. A longitudinal study was performed over six months (2007-8) where patients were assessed using the scales after admission and before discharge. A convenience sample of 1,542 patients was recruited in an Austrian rehabilitation centre. The CDS-R and the Barthel Index. Responsiveness was determined by descriptive analysis, significance tests and calculation of effect sizes. For the 1,542 patients, the calculation according to Kazis yielded values of 0.10 for both instruments. For the group of patients who showed clinically relevant changes, values of 0.50 were obtained for the CDS-R and 1.06 for the Barthel Index. For the group 1,542 patients, the calculation according to Liang yielded values of 0.42 for the CDS-R and 0.34 for the Barthel Index. For the group of patients who showed clinically relevant changes, values of 1.47 were obtained for the CDS-R and 1.92 for the Barthel Index. The Barthel Index seems to be slightly more responsive than the CDS-R, and both instruments seem to be appropriate for the assessment of patients' changes over time. Nevertheless, the exact level of responsiveness could not be clearly identified for both instruments. To confirm the level of responsiveness, further research is recommended.

  13. Scaling the Drosophila Wing: TOR-Dependent Target Gene Access by the Hippo Pathway Transducer Yorkie.

    Science.gov (United States)

    Parker, Joseph; Struhl, Gary

    2015-10-01

    Organ growth is controlled by patterning signals that operate locally (e.g., Wingless/Ints [Wnts], Bone Morphogenetic Proteins [BMPs], and Hedgehogs [Hhs]) and scaled by nutrient-dependent signals that act systemically (e.g., Insulin-like peptides [ILPs] transduced by the Target of Rapamycin [TOR] pathway). How cells integrate these distinct inputs to generate organs of the appropriate size and shape is largely unknown. The transcriptional coactivator Yorkie (Yki, a YES-Associated Protein, or YAP) acts downstream of patterning morphogens and other tissue-intrinsic signals to promote organ growth. Yki activity is regulated primarily by the Warts/Hippo (Wts/Hpo) tumour suppressor pathway, which impedes nuclear access of Yki by a cytoplasmic tethering mechanism. Here, we show that the TOR pathway regulates Yki by a separate and novel mechanism in the Drosophila wing. Instead of controlling Yki nuclear access, TOR signaling governs Yki action after it reaches the nucleus by allowing it to gain access to its target genes. When TOR activity is inhibited, Yki accumulates in the nucleus but is sequestered from its normal growth-promoting target genes--a phenomenon we term "nuclear seclusion." Hence, we posit that in addition to its well-known role in stimulating cellular metabolism in response to nutrients, TOR also promotes wing growth by liberating Yki from nuclear seclusion, a parallel pathway that we propose contributes to the scaling of wing size with nutrient availability.

  14. Anisotropy, reversibility and scale dependence of transport properties in single fracture and fractured zone - Non-sorbing tracer experiment at the Kamaishi mine

    International Nuclear Information System (INIS)

    Sawada, Atushi; Uchida, Masahiro; Shimo, Michito; Yamamoto, Hajime; Takahara, Hiroyuki; Doe, T.W.

    2001-01-01

    A comprehensive set of the non-sorbing tracer experiments were run in the granodiorite of the Kamaishi mine located in the northern part of the main island of Japan-Honshu. A detailed geo-hydraulic investigation was carried out prior to performing the tracer migration experiments. The authors conducted a detailed but simple investigation in order to understand the spatial distribution of conductive fractures and the pressure field. Seven boreholes were drilled in the test area of which dimension is approximately 80 meters by 60 meters, revealing hydraulic compartmentalization and a heterogeneous distribution of conductive features. Central three boreholes which are approx. 2 to 4 meters apart form a triangle array. After identifying two hydraulically isolated fractures and one fractured zone, a comprehensive non-sorbing tracer experiments were conducted. Four different dipole fields were used to study the heterogeneity within a fracture. Firstly, anisotropy was studied using the central borehole array of three boreholes and changing injection/withdrawal wells. Secondly, dipole ratio was varied to study how prume spread could affect the result. Thirdly, reversibility was studied by switching injection/withdrawal wells. Lastly, scale dependency was studied by using outer boreholes. The tracer breakthrough curves were analyzed by using a streamline, analytical solution and numerical analysis of mass transport. Best-fit calculations of the experimental breakthrough curves were obtained by assigning apertures within the range of 1-10 times the square root of transmissivity and a dispersion length equal to 1/10 of the migration length. Different apertures and dispersion lengths were also interpreted in anisotropy case, reversibility case and scale dependency case. Fractured zone indicated an increased aperture and increased dispersivity

  15. Large-Scale Phosphoproteomics Reveals Shp-2 Phosphatase-Dependent Regulators of Pdgf Receptor Signaling

    Directory of Open Access Journals (Sweden)

    Tanveer S. Batth

    2018-03-01

    Full Text Available Despite its low cellular abundance, phosphotyrosine (pTyr regulates numerous cell signaling pathways in health and disease. We applied comprehensive phosphoproteomics to unravel differential regulators of receptor tyrosine kinase (RTK-initiated signaling networks upon activation by Pdgf-ββ, Fgf-2, or Igf-1 and identified more than 40,000 phosphorylation sites, including many phosphotyrosine sites without additional enrichment. The analysis revealed RTK-specific regulation of hundreds of pTyr sites on key signaling molecules. We found the tyrosine phosphatase Shp-2 to be the master regulator of Pdgfr pTyr signaling. Application of a recently introduced allosteric Shp-2 inhibitor revealed global regulation of the Pdgf-dependent tyrosine phosphoproteome, which significantly impaired cell migration. In addition, we present a list of hundreds of Shp-2-dependent targets and putative substrates, including Rasa1 and Cortactin with increased pTyr and Gab1 and Erk1/2 with decreased pTyr. Our study demonstrates that large-scale quantitative phosphoproteomics can precisely dissect tightly regulated kinase-phosphatase signaling networks.

  16. Multi-length scale tomography for the determination and optimization of the effective microstructural properties in novel hierarchical solid oxide fuel cell anodes

    Science.gov (United States)

    Lu, Xuekun; Taiwo, Oluwadamilola O.; Bertei, Antonio; Li, Tao; Li, Kang; Brett, Dan J. L.; Shearing, Paul R.

    2017-11-01

    Effective microstructural properties are critical in determining the electrochemical performance of solid oxide fuel cells (SOFCs), particularly when operating at high current densities. A novel tubular SOFC anode with a hierarchical microstructure, composed of self-organized micro-channels and sponge-like regions, has been fabricated by a phase inversion technique to mitigate concentration losses. However, since pore sizes span over two orders of magnitude, the determination of the effective transport parameters using image-based techniques remains challenging. Pioneering steps are made in this study to characterize and optimize the microstructure by coupling multi-length scale 3D tomography and modeling. The results conclusively show that embedding finger-like micro-channels into the tubular anode can improve the mass transport by 250% and the permeability by 2-3 orders of magnitude. Our parametric study shows that increasing the porosity in the spongy layer beyond 10% enhances the effective transport parameters of the spongy layer at an exponential rate, but linearly for the full anode. For the first time, local and global mass transport properties are correlated to the microstructure, which is of wide interest for rationalizing the design optimization of SOFC electrodes and more generally for hierarchical materials in batteries and membranes.

  17. Derivation of effective fission gas diffusivities in UO2 from lower length scale simulations and implementation of fission gas diffusion models in BISON

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pastore, Giovanni [Idaho National Lab. (INL), Idaho Falls, ID (United States); Liu, Xiang-Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perriot, Romain Thibault [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tonks, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Stanek, Christopher Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-07

    This report summarizes the development of new fission gas diffusion models from lower length scale simulations and assessment of these models in terms of annealing experiments and fission gas release simulations using the BISON fuel performance code. Based on the mechanisms established from density functional theory (DFT) and empirical potential calculations, continuum models for diffusion of xenon (Xe) in UO2 were derived for both intrinsic conditions and under irradiation. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and stability. These models were implemented in the MARMOT phase field code, which is used to calculate effective Xe diffusivities for various irradiation conditions. The effective diffusivities were used in BISON to calculate fission gas release for a number of test cases. The results are assessed against experimental data and future directions for research are outlined based on the conclusions.

  18. Investigating the dependence of SCM simulated precipitation and clouds on the spatial scale of large-scale forcing at SGP

    Science.gov (United States)

    Tang, Shuaiqi; Zhang, Minghua; Xie, Shaocheng

    2017-08-01

    Large-scale forcing data, such as vertical velocity and advective tendencies, are required to drive single-column models (SCMs), cloud-resolving models, and large-eddy simulations. Previous studies suggest that some errors of these model simulations could be attributed to the lack of spatial variability in the specified domain-mean large-scale forcing. This study investigates the spatial variability of the forcing and explores its impact on SCM simulated precipitation and clouds. A gridded large-scale forcing data during the March 2000 Cloud Intensive Operational Period at the Atmospheric Radiation Measurement program's Southern Great Plains site is used for analysis and to drive the single-column version of the Community Atmospheric Model Version 5 (SCAM5). When the gridded forcing data show large spatial variability, such as during a frontal passage, SCAM5 with the domain-mean forcing is not able to capture the convective systems that are partly located in the domain or that only occupy part of the domain. This problem has been largely reduced by using the gridded forcing data, which allows running SCAM5 in each subcolumn and then averaging the results within the domain. This is because the subcolumns have a better chance to capture the timing of the frontal propagation and the small-scale systems. Other potential uses of the gridded forcing data, such as understanding and testing scale-aware parameterizations, are also discussed.

  19. Scale dependency in effectiveness, isolation, and social-ecological spillover of protected areas.

    Science.gov (United States)

    Ament, Judith M; Cumming, Graeme S

    2016-08-01

    Protected areas are considered vital for the conservation of biodiversity. Given their central role in many conservation strategies, it is important to know whether they adequately protect biodiversity within their boundaries; whether they are becoming more isolated from other natural areas over time; and whether they play a role in facilitating or reducing land-cover change in their surroundings. We used matching methods and national and local analyses of land-cover change to evaluate the combined effectiveness (i.e., avoided natural-cover loss), isolation (i.e., changes in adjacent areas), and spillover effects (i.e., impacts on adjacent areas) of 19 national parks in South Africa from 2000 to 2009. All parks had either similar or lower rates of natural-cover loss than matched control samples. On a national level, mean net loss of natural cover and mean net gain of cultivation cover decreased with distance from park boundary, but there was considerable variation in trends around individual parks, providing evidence for both increased isolation and buffering of protected areas. Fourteen parks had significant positive spillover and reduced natural-cover loss in their surroundings, whereas five parks experienced elevated levels of natural-cover loss. Conclusions about social-ecological spillover effects from protected areas depended heavily on the measures of land-cover change used and the scale at which the results were aggregated. Our findings emphasize the need for high-resolution data when assessing spatially explicit phenomena such as land-cover change and challenge the usefulness of large-scale (coarse grain, broad extent) studies for understanding social-ecological dynamics around protected areas. © 2016 Society for Conservation Biology.

  20. Modeling Scale and Orientation-Dependent Effects in Snow Particles at Microwave Wavelengths

    Science.gov (United States)

    Honeyager, R. E.; Liu, G.; Nowell, H.

    2013-12-01

    With the advent of satellite-borne radar and radiometers, it is now possible to observe cloud processes throughout the globe with unprecedented levels of precision. However, interpreting the large amount of data generated by such instruments requires detailed understanding of how light is scattered in-cloud by ice. Unlike liquid water, ice exhibits complex shapes and orientation-dependent effects. This is of particularly great importance at microwave wavelengths, where ice aggregates are easily detected by radar and radiometers. When modeling such irregular particles, it is desirable to have a large collection of particle that resemble those found in nature. There is a tradeoff, however, in modeling fine features of particles and system resources (processing time and memory requirements). This becomes increasingly significant at particle sizes that are significantly larger than the considered wavelengths. Both pristine flakes and aspect-ratio correct bullet rosette aggregates were first considered using the Discrete Dipole Approximation. These initial flakes were subjected to a variety of decimation conditions, where adjacent dipoles were combined, thus producing equivalent particles with slightly lower fractal complexity. Calculations using such decimated particles were an order of magnitude faster, and exhibited scattering cross-sections to within twenty percent of initial values. Similar methods of approximating particles with dielectric-scaled ellipsoids and clusters of spherical particles were also examined using the T-matrix method. Many microwave radiative transfer models currently make the implicit assumption that all scattering sources are randomly oriented. This is generally true of the bulk atmosphere, but dynamical simulations suggest that this does not hold for asymmetric ice crystals in nonturbulent conditions. Ensembles of such particles were constructed according to established size, density and aspect ratio relationships. Relative orientation

  1. Size variation and collapse of emphysema holes at inspiration and expiration CT scan: evaluation with modified length scale method and image co-registration

    Directory of Open Access Journals (Sweden)

    Oh SY

    2017-07-01

    Full Text Available Sang Young Oh,1,* Minho Lee,1,* Joon Beom Seo,1,* Namkug Kim,1,2,* Sang Min Lee,1 Jae Seung Lee,3 Yeon Mok Oh3 1Department of Radiology, 2Department of Convergence Medicine, 3Department of Pulmonology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: A novel approach of size-based emphysema clustering has been developed, and the size variation and collapse of holes in emphysema clusters are evaluated at inspiratory and expiratory computed tomography (CT. Thirty patients were visually evaluated for the size-based emphysema clustering technique and a total of 72 patients were evaluated for analyzing collapse of the emphysema hole in this study. A new approach for the size differentiation of emphysema holes was developed using the length scale, Gaussian low-pass filtering, and iteration approach. Then, the volumetric CT results of the emphysema patients were analyzed using the new method, and deformable registration was carried out between inspiratory and expiratory CT. Blind visual evaluations of EI by two readers had significant correlations with the classification using the size-based emphysema clustering method (r-values of reader 1: 0.186, 0.890, 0.915, and 0.941; reader 2: 0.540, 0.667, 0.919, and 0.942. The results of collapse of emphysema holes using deformable registration were compared with the pulmonary function test (PFT parameters using the Pearson’s correlation test. The mean extents of low-attenuation area (LAA, E1 (<1.5 mm, E2 (<7 mm, E3 (<15 mm, and E4 (≥15 mm were 25.9%, 3.0%, 11.4%, 7.6%, and 3.9%, respectively, at the inspiratory CT, and 15.3%, 1.4%, 6.9%, 4.3%, and 2.6%, respectively at the expiratory CT. The extents of LAA, E2, E3, and E4 were found to be significantly correlated with the PFT ­parameters (r=−0.53, −0.43, −0.48, and −0.25, with forced expiratory volume in 1 second (FEV1; −0.81, −0.62, −0.75, and

  2. Evidence-Based Thresholds for the Volume and Length of Stay Relationship in Total Hip Arthroplasty: Outcomes and Economies of Scale.

    Science.gov (United States)

    Ramkumar, Prem N; Navarro, Sergio M; Frankel, William C; Haeberle, Heather S; Delanois, Ronald E; Mont, Michael A

    2018-02-05

    Several studies have indicated that high-volume surgeons and hospitals deliver higher value care. However, no evidence-based volume thresholds currently exist in total hip arthroplasty (THA). The primary objective of this study was to establish meaningful thresholds taking patient outcomes into consideration for surgeons and hospitals performing THA. A secondary objective was to examine the market share of THAs for each surgeon and hospital strata. Using 136,501 patients undergoing hip arthroplasty, we used stratum-specific likelihood ratio (SSLR) analysis of a receiver-operating characteristic curve to generate volume thresholds predictive of increased length of stay (LOS) for surgeons and hospitals. Additionally, we examined the relative proportion of annual THA cases performed by each surgeon and hospital strata established. SSLR analysis of LOS by annual surgeon THA volume produced 3 strata: 0-69 (low), 70-121 (medium), and 121 or more (high). Analysis by annual hospital THA volume produced strata at: 0-120 (low), 121-357 (medium), and 358 or more (high). LOS decreased significantly (P economies of scale in THA by demonstrating a direct relationship between volume and value for THA through risk-based volume stratification of surgeons and hospitals using SSLR analysis of receiver-operating characteristic curves to identify low-, medium-, and high-volume surgeons and hospitals. While the majority of primary THAs are performed at high-volume centers, low-volume surgeons are performing the majority of these cases, which may offer room for improvement in delivering value-based care. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Statistical inference and visualization in scale-space for spatially dependent images

    KAUST Repository

    Vaughan, Amy

    2012-03-01

    SiZer (SIgnificant ZERo crossing of the derivatives) is a graphical scale-space visualization tool that allows for statistical inferences. In this paper we develop a spatial SiZer for finding significant features and conducting goodness-of-fit tests for spatially dependent images. The spatial SiZer utilizes a family of kernel estimates of the image and provides not only exploratory data analysis but also statistical inference with spatial correlation taken into account. It is also capable of comparing the observed image with a specific null model being tested by adjusting the statistical inference using an assumed covariance structure. Pixel locations having statistically significant differences between the image and a given null model are highlighted by arrows. The spatial SiZer is compared with the existing independent SiZer via the analysis of simulated data with and without signal on both planar and spherical domains. We apply the spatial SiZer method to the decadal temperature change over some regions of the Earth. © 2011 The Korean Statistical Society.

  4. Can the Northwick Park Dependency Scale be translated to a Barthel Index?

    Science.gov (United States)

    Turner-Stokes, Lynne; Williams, Heather; Howley, Deirdre; Jackson, Diana

    2010-12-01

    to develop and test an algorithm for conversion of the Northwick Park Dependency Scale (NPDS) to a Barthel Index. conversion criteria were developed to derive a Barthel Index from NPDS data. The criteria were then applied in two community-based datasets of NPDS and Barthel scores, gathered from carers/patients via postal questionnaires. A retrospective exploratory analysis (dataset A) was followed by prospective confirmatory analysis (dataset B). patients with neurological disabilities, mainly following acquired brain injury: dataset A (n = 225) and dataset B (n = 96). comparison of NPDS-derived Barthel scores with parallel directly rated Barthel scores. the exploratory analysis identified that one Barthel item ('Stairs') could not be derived from the NPDS items alone, and required minor adaptation of one of the five additional questions that are included to translate the NPDS into an assessment of community care needs (Northwick Park Care Needs Assessment, NPCNA). For the prospective confirmatory analysis, the NPCNA 'Stairs' question was adjusted to support full conversion. Very strong intraclass correlations were observed between the total 'direct' and 'derived' Barthel scores (0.97 (dataset A), 0.95 (dataset B), PBarthel Index can be reliably derived from NPDS and NPCNA data through a conversion algorithm which has now been built into the supporting software package.

  5. Scale-dependence of Cope's rule in body size evolution of Paleozoic brachiopods.

    Science.gov (United States)

    Novack-Gottshall, Philip M; Lanier, Michael A

    2008-04-08

    The average body size of brachiopods from a single habitat type increased gradually by more than two orders of magnitude during their initial Cambrian-Devonian radiation. This increase occurred nearly in parallel across all major brachiopod clades (classes and orders) and is consistent with Cope's rule: the tendency for size to increase over geological time. The increase is not observed within small, constituent clades (represented here by families), which underwent random, unbiased size changes. This scale-dependence is caused by the preferential origination of new families possessing initially larger body sizes. However, this increased family body size does not confer advantages in terms of greater geological duration or genus richness over families possessing smaller body sizes. We suggest that the combination of size-biased origination of families and parallel size increases among major, more inclusive brachiopod clades from a single habitat type is best explained by long-term, secular environmental changes during the Paleozoic that provided opportunities for body size increases associated with major morphological evolution.

  6. Dependence of the length of the hydrogen bond on the covalent and cationic radii of hydrogen, and additivity of bonding distances

    Czech Academy of Sciences Publication Activity Database

    Heyrovská, Raji

    2006-01-01

    Roč. 432, č. 1-3 (2006), s. 348-351 ISSN 0009-2614 R&D Projects: GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507 Keywords : length of the hydrogen bond * ionic radius * Golden ratio Subject RIV: BO - Biophysics Impact factor: 2.462, year: 2006

  7. Inhibition of nuclear T3 binding by fatty acids: dependence on chain length, unsaturated bonds, cis-trans configuration and esterification

    NARCIS (Netherlands)

    Wiersinga, W. M.; Platvoet-ter Schiphorst, M.

    1990-01-01

    1. Fatty acids have the capacity for inhibition of nuclear T3 binding (INB). The present studies were undertaken to describe the INB-activity of fatty acids as a function of chain length, unsaturated bonds, cis-trans configuration, and esterification. 2. Isolated rat liver nuclei were incubated with

  8. Scale dependence of absorption of photosynthetically active radiation in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Asner, G.P.; Wessman, C.A.; Archer, S.

    1998-01-01

    The fraction of photosynthetically active radiation absorbed by plant canopies (fAPAR) is a critical biophysical variable for extrapolating ecophysiological measurements from the leaf to landscape scale. Quantification of fAPAR determinants at the landscape level is needed to improve the interpretation of remote sensing data, to facilitate its use in constraining ecosystem process models, and to improve synoptic-scale links between carbon and nutrient cycles. Most canopy radiation budget studies have focused on light attenuation in plant canopies, with little regard for the importance of the scale-dependent biophysical and structural factors (e.g., leaf and stem optical properties, leaf and stem area, and extent of vegetation structural types) that ultimately determine fAPAR at canopy and landscape scales. Most studies have also assumed that nonphotosynthetic vegetation (litter and stems) contributes little to fAPAR. Using a combined field measurement and radiative transfer modeling approach, we quantified (a) the relative role of the leaf-, canopy-, and landscape-level factors that determine fAPAR in terrestrial ecosystems and (b) the magnitude of PAR absorption by grass litter and woody plant stems. Variability in full spectral-range (400–2500 nm) reflectance/transmittance and PAR (400–700 nm) absorption at the level of individual leaf, stem, and litter samples was quantified for a wide array of broadleaf arborescent and grass species along a 900-km north–south Texas savanna transect. Among woody growth forms, leaf reflectance and transmittance spectra were statistically comparable between populations, species within a genus, and functional types (deciduous vs. evergreen, legume vs. nonlegume). Within the grass life-form, spectral properties were statistically comparable between species and C 3 /C 4 physiologies. We found that tissue-level PAR absorption among species, genera, functional groups, and growth forms and between climatologically diverse regions

  9. Motivation for treatment in substance-dependent patients. Psychometric evaluation of the TCU motivation for treatment scales.

    Science.gov (United States)

    De Weert-Van Oene, Gerdien H; Schippers, Gerard M; De Jong, Cor A J; Schrijvers, Guus A J P

    2002-01-01

    The objective of this paper is to analyze the psychometric properties of the TCU Motivation for Treatment (MfT) scale in alcohol- and drug-dependent patients in an inpatient treatment facility in the Netherlands, to see whether it is useful in European populations as well. In the study, 279 consecutive patients were enrolled: 132 drug and 147 alcohol dependents. Exploratory and confirmatory factor analysis revealed 4 subscales: recognition of general problems (4 items), recognition of specific problems (5), desire for help (5) and treatment readiness (8). The results of the analyses showed that the MfT scale is a valid instrument for measuring treatment motivation, both in drug- and in alcohol-dependent patients. We demonstrated evidence for consistency of the scale through cultural barriers, in different populations and in different treatment settings. Copyright 2002 S. Karger AG, Basel

  10. Transition from non-Fickian to Fickian longitudinal transport through 3-D rough fractures: Scale-(in)sensitivity and roughness dependence

    Science.gov (United States)

    Wang, Lichun; Bayani Cardenas, M.

    2017-03-01

    Understanding transport in rough fractures from non-Fickian to Fickian regimes and the prediction of non-Fickian transport is critical for the development of new transport theories and many practical applications. Through computational experiments that fall within the macrodispersion regime, we first simulated and analyzed solute transport through synthetic rough fractures with stationary geometrical properties (i.e., fracture roughness σb/〈b〉 and correlation length λ, where b refers to aperture with its standard deviation σb and arithmetic mean 〈b〉) across increasing fracture longitudinal transport domain length L, with L/λ ranging from 2.5 to 50. The results were used to determine how solute transport behavior evolves with increasing scale in the longitudinal direction. Moreover, a set of correlated fractures with aperture fields following normal and log-normal distributions was created to further identify and quantify the dependence of non-Fickian transport on roughness. We found that although persistent intermittent velocity structures were present, the breakthrough curves (BTCs) and residence time distributions showed diminishing early arrival and tailing, features of non-Fickian transport, with increasing longitudinal L/λ, ultimately converging to a Fickian transport regime given σb/〈b〉 remained constant. Inverse analysis of the experimental BTCs with the advection-dispersion equation (ADE) model showed that the dispersion coefficient (D) was non-trivially scale-dependent. Simulation results for rough fractures with varying σb/〈b〉 and L/λ indicated that the ratio of fluid velocity to transport velocity fitted to the ADE model depends on σb/〈b〉 and L/λ. The continuous time random walk (CTRW) performed much better across all transport scales, and resulted in scale-independent fitted parameters, i.e., β in the memory function. The fitted β is proportional to σb/〈b〉but is insensitive to L/λ. Therefore, bulk longitudinal

  11. A rate-dependent multi-scale crack model for concrete

    NARCIS (Netherlands)

    Karamnejad, A.; Nguyen, V.P.; Sluys, L.J.

    2013-01-01

    A multi-scale numerical approach for modeling cracking in heterogeneous quasi-brittle materials under dynamic loading is presented. In the model, a discontinuous crack model is used at macro-scale to simulate fracture and a gradient-enhanced damage model has been used at meso-scale to simulate

  12. Mechanical Behavior of UO2 at Sub-grain Length Scales: Quantification of Elastic, Plastic and Creep Properties via Microscale Testing

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, Pedro

    2018-04-16

    concluded successfully, resulting in: 1) the successful fabrication, processing, and characterization of large-grained samples with various orientations (up to and including single crystals) having stoichiometric and hyper-stoichiometric O/U ratios; 2) formulation, calibration, and validation of a crystal plasticity constitutive model to describe the creep deformation of UO2 at the sub-grain length scale (single crystal level) at intermediate temperatures; 3) the successful calibration of a crystal plasticity constitutive model to describe the elasto-plastic deformation of microcantilever beams, also at moderate temperatures. Samples were prepared from natural uranium oxide powder of production-quality provided by Areva. The powder was pressed in a die to a pressure of 100 MPa to produce green pellets with no sintering aids, lubricants, or any other additives. The green pellets were then heated up to 1700 °C under ultra-high purity argon atmosphere (~1 ppm O2). The atmosphere was then changed to 79% Argon, 21% O2 and the temperature was held at 1700 °C for 2 hours to sinter the pellets under oxidative conditions [1] that are known to increase grain growth kinetics in UO2 [2]. Samples were then cooled down under Ar-4%H2 atmosphere to reduce the samples back to stoichiometric UO2. For macro-scale procedures, testing of UO2 samples with large grains was performed at 1200 °C using a modified load frame capable of applying dead-weight loads to ensure constant stress conditions, while displacement of the sample produced by the applied load was measured with high precision micrometers to obtain strains. Stress steps were used during testing and the strains were monitored to measured creep strain rates under steady state for each level of stress used, so that stress exponents could be obtained. The results of the mechanical testing, along with sample geometry and crystal orientation of the grains in the samples, as well as post-test sample characterization were used to formulate

  13. Length expectation values in quantum Regge calculus

    International Nuclear Information System (INIS)

    Khatsymovsky, V.M.

    2004-01-01

    Regge calculus configuration superspace can be embedded into a more general superspace where the length of any edge is defined ambiguously depending on the 4-tetrahedron containing the edge. Moreover, the latter superspace can be extended further so that even edge lengths in each the 4-tetrahedron are not defined, only area tensors of the 2-faces in it are. We make use of our previous result concerning quantization of the area tensor Regge calculus which gives finite expectation values for areas. Also our result is used showing that quantum measure in the Regge calculus can be uniquely fixed once we know quantum measure on (the space of the functionals on) the superspace of the theory with ambiguously defined edge lengths. We find that in this framework quantization of the usual Regge calculus is defined up to a parameter. The theory may possess nonzero (of the order of Planck scale) or zero length expectation values depending on whether this parameter is larger or smaller than a certain value. Vanishing length expectation values means that the theory is becoming continuous, here dynamically in the originally discrete framework

  14. Comparisons of three nicotine dependence scales in a multiethnic sample of young adult menthol and non-menthol smokers.

    Science.gov (United States)

    Fagan, Pebbles; Pohkrel, Pallav; Herzog, Thaddeus; Pagano, Ian; Vallone, Donna; Trinidad, Dennis R; Sakuma, Kari-Lyn; Sterling, Kymberle; Fryer, Craig S; Moolchan, Eric

    2015-04-01

    Few studies have compared nicotine dependence among menthol and non-menthol cigarette smokers in a multiethnic sample of young adult daily cigarette smokers. This study examines differences in nicotine dependence among menthol and non-menthol daily smokers and the associations of nicotine dependence with quitting behaviors among Native Hawaiian, Filipino, and White cigarette smokers aged 18-35. Craigslist.org, newspaper advertisements, and peer-to-peer referrals were used to recruit daily smokers (n = 186) into a lab-based study. Nicotine dependence was assessed using the Fagerstrom Test of Nicotine Dependence (FTND), the Nicotine Dependence Syndrome Scale (NDSS), and the brief Wisconsin Inventory for Smoking Dependence Motives (WISDM). Multiple regression analyses were used to examine differences in nicotine dependence between menthol and non-menthol smokers and the relationship between each nicotine dependence scale with self-efficacy to quit, quit attempt in the past 12 months, and number of attempts. Menthol smokers were more likely to report difficulty refraining from smoking in places where forbidden (p = .04) and had higher scores on social/environmental goads subscale of the WISDM (p = .0005). Two-way interaction models of the FTND and menthol status showed that menthol smokers with higher levels of dependence were more likely to have tried to quit smoking in the past 12 months (p = .02), but were less likely to have had multiple quit attempts (p = .01). Components of the FTND and WISDM distinguish levels of dependence between menthol and non-menthol smokers. Higher FTND scores were associated with having a quit attempt, but fewer quit attempts among menthol smokers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Critical bands and mixed-frequency scaling: sequential dependencies, equal-loudness contours, and power function exponents.

    Science.gov (United States)

    Ward, L M

    1990-06-01

    Stimuli of random intensities and various but predictable frequencies were presented for repeated magnitude estimations on the same scale (mixed-frequency scaling). The frequencies for a particular judgment session were selected so that they lay either inside each other's critical bands or outside them. Contrastive dependencies of current magnitude estimation responses on previous stimuli of a different frequency were significantly affected by whether the two frequencies were inside or outside each other's critical bands, while assimilative dependencies were not. This reinforces the idea that such dependencies are sensory in nature and arise from a different mechanism than do the assimilative dependencies. Mixed-frequency scaling of loudness also gives rise to cross-frequency matching functions from which equal-loudness contours can be calculated. These contours calculated from the present judgments are similar to those produced from other methods, even when they are extrapolated to untested intensities. Power function exponents for loudness scaled in this way are larger for lower frequencies, as has been found in previous studies, and are consistent with the flattening of the calculated equal-loudness contours for low frequencies as intensity increases.

  16. Motivation for treatment in substance-dependent patients. Psychometric evaluation of the TCU motivation for treatment scales

    NARCIS (Netherlands)

    de Weert-van Oene, Gerdien H.; Schippers, Gerard M.; de Jong, Cor A. J.; Schrijvers, Guus A. J. P.

    2002-01-01

    The objective of this paper is to analyze the psychometric properties of the TCU Motivation for Treatment (MfT) scale in alcohol- and drug-dependent patients in an inpatient treatment facility in the Netherlands, to see whether it is useful in European populations as well. In the study, 279

  17. Reducing the item number to obtain the same-length self-assessment scales: a systematic approach using result of graphical loglinear rasch models

    DEFF Research Database (Denmark)

    Nielsen, Tine; Kreiner, Svend

    2011-01-01

    . For self-assessment, self-scoring and self-interpretational purposes it is deemed prudent that subscales measuring comparable constructs are of the same item length. Consequently, in order to obtain a self-assessment version of the R-D-LSI with an equal number of items in each subscale, a systematic...... approach to item reduction based on results of graphical loglinear Rasch modeling (GLLRM) was designed. This approach was then used to reduce the number of items in the subscales of the R-D-LSI which had an item-length of more than seven items, thereby obtaining the Danish Self-Assessment Learning Styles...

  18. Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming.

    Science.gov (United States)

    Lin, Yong; Franzke, Christian L E

    2015-08-11

    Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary.

  19. Scale-dependency of the global mean surface temperature trend and its implication for the recent hiatus of global warming

    Science.gov (United States)

    Lin, Yong; Franzke, Christian L. E.

    2015-01-01

    Studies of the global mean surface temperature trend are typically conducted at a single (usually annual or decadal) time scale. The used scale does not necessarily correspond to the intrinsic scales of the natural temperature variability. This scale mismatch complicates the separation of externally forced temperature trends from natural temperature fluctuations. The hiatus of global warming since 1999 has been claimed to show that human activities play only a minor role in global warming. Most likely this claim is wrong due to the inadequate consideration of the scale-dependency in the global surface temperature (GST) evolution. Here we show that the variability and trend of the global mean surface temperature anomalies (GSTA) from January 1850 to December 2013, which incorporate both land and sea surface data, is scale-dependent and that the recent hiatus of global warming is mainly related to natural long-term oscillations. These results provide a possible explanation of the recent hiatus of global warming and suggest that the hiatus is only temporary. PMID:26259555

  20. Studying the time scale dependence of environmental variables predictability using fractal analysis.

    Science.gov (United States)

    Yuval; Broday, David M

    2010-06-15

    Prediction of meteorological and air quality variables motivates a lot of research in the atmospheric sciences and exposure assessment communities. An interesting related issue regards the relative predictive power that can be expected at different time scales, and whether it vanishes altogether at certain ranges. An improved understanding of our predictive powers enables better environmental management and more efficient decision making processes. Fractal analysis is commonly used to characterize the self-affinity of time series. This work introduces the Continuous Wavelet Transform (CWT) fractal analysis method as a tool for assessing environmental time series predictability. The high temporal scale resolution of the CWT enables detailed information about the Hurst parameter, a common temporal fractality measure, and thus about time scale variations in predictability. We analyzed a few years records of half-hourly air pollution and meteorological time series from which the trivial seasonal and daily cycles were removed. We encountered a general trend of decreasing Hurst values from about 1.4 (good autocorrelation and predictability), in the sub-daily time scale to 0.5 (which implies complete randomness) in the monthly to seasonal scales. The air pollutants predictability follows that of the meteorological variables in the short time scales but is better at longer scales.

  1. Scale-dependence in polychlorinated biphenyl (PCB) exposure effects on waterbird habitat occupancy.

    Science.gov (United States)

    Gibbs, James P; Rouhani, Shahrokh; Shams, Leyla

    2017-08-01

    Spatial scale is rarely considered in population-level assessments of contaminant impacts on wild animals; as a result misinterpretation of the relationship between contaminant exposure and population status may occur. We assessed the strength of expression of polychlorinated biphenyl (PCB) exposure effects at local vs. regional spatial scales on population status in five species of waterbirds, "bioaccumulators" often promoted as indicators of contaminant effects in aquatic ecosystems. Our focus was the upper Hudson River where PCBs occur at levels reported to have adverse impacts on wild birds. At the local scale, waterbird habitat occupancy was estimated from 220 repeat surveys made between 2001 and 2010 along the same survey route divided into 25 contiguous river segments with markedly different PCB concentrations. At the regional scale, waterbird habitat occupancy in relation to proximity to the upper Hudson River was estimated across 1248 Breeding Bird Atlas survey blocks while controlling for region-wide variation in habitat availability. At the local scale, many associations of habitat and sampling covariates with species detection probabilities were evident but none, including PCB concentration, with habitat occupancy, extinction or colonization of a given river segment. At the regional scale, survey effort and habitat factors not related to PCB exposure were the most important drivers of waterbird occurrence although two species were more likely to occur farther from the contaminated river segment. Spatial scale clearly mediates expression of contaminant impacts on wild bird populations; large-scale, expert-generated databases provide an underused opportunity for better delineating the spatial scales at which population impacts occur and risk assessments should be performed.

  2. Large-Scale Phosphoproteomics Reveals Shp-2 Phosphatase-Dependent Regulators of Pdgf Receptor Signaling

    DEFF Research Database (Denmark)

    Batth, Tanveer S; Papetti, Moreno; Pfeiffer, Anamarija

    2018-01-01

    of Pdgfr pTyr signaling. Application of a recently introduced allosteric Shp-2 inhibitor revealed global regulation of the Pdgf-dependent tyrosine phosphoproteome, which significantly impaired cell migration. In addition, we present a list of hundreds of Shp-2-dependent targets and putative substrates...

  3. Estimated allele substitution effects underlying genomic evaluation models depend on the scaling of allele counts.

    Science.gov (United States)

    Bouwman, Aniek C; Hayes, Ben J; Calus, Mario P L

    2017-10-30

    Genomic evaluation is used to predict direct genomic values (DGV) for selection candidates in breeding programs, but also to estimate allele substitution effects (ASE) of single nucleotide polymorphisms (SNPs). Scaling of allele counts influences the estimated ASE, because scaling of allele counts results in less shrinkage towards the mean for low minor allele frequency (MAF) variants. Scaling may become relevant for estimating ASE as more low MAF variants will be used in genomic evaluations. We show the impact of scaling on estimates of ASE using real data and a theoretical framework, and in terms of power, model fit and predictive performance. In a dairy cattle dataset with 630 K SNP genotypes, the correlation between DGV for stature from a random regression model using centered allele counts (RRc) and centered and scaled allele counts (RRcs) was 0.9988, whereas the overall correlation between ASE using RRc and RRcs was 0.27. The main difference in ASE between both methods was found for SNPs with a MAF lower than 0.01. Both the ratio (ASE from RRcs/ASE from RRc) and the regression coefficient (regression of ASE from RRcs on ASE from RRc) were much higher than 1 for low MAF SNPs. Derived equations showed that scenarios with a high heritability, a large number of individuals and a small number of variants have lower ratios between ASE from RRc and RRcs. We also investigated the optimal scaling parameter [from - 1 (RRcs) to 0 (RRc) in steps of 0.1] in the bovine stature dataset. We found that the log-likelihood was maximized with a scaling parameter of - 0.8, while the mean squared error of prediction was minimized with a scaling parameter of - 1, i.e., RRcs. Large differences in estimated ASE were observed for low MAF SNPs when allele counts were scaled or not scaled because there is less shrinkage towards the mean for scaled allele counts. We derived a theoretical framework that shows that the difference in ASE due to shrinkage is heavily influenced by the

  4. Dependency of Anion and Chain Length of Imidazolium Based Ionic Liquid on Micellization of the Block Copolymer F127 in Aqueous Solution: An Experimental Deep Insight

    Directory of Open Access Journals (Sweden)

    Jignesh Lunagariya

    2017-07-01

    Full Text Available The non-ionic triblock copolymer, Pluronic® F127, has been selected to observe its interaction with ionic liquids (ILs in aqueous solutions by using DLS, surface tension, and viscosity measurements. The Critical Micelle Concentration (CMC of F127 increased with the addition of ILs, which appeared logical since it increases the solubility of PPO (and PEO moiety, making it behaves more like a hydrophilic block copolymer that is micellized at a higher copolymer concentration. The results from DLS data showed good agreement with those obtained from the surface tension measurements. Upon the addition of ILs, the tendency in micellar size reduction was demonstrated by viscosity results, and therefore, intrinsic viscosity decreased compared to pure F127 in aqueous solution. The results were discussed as a function of alkyl chain length and anions of imidazolium based ILs.

  5. On a comparative study between dependence scales determined by linear and non-linear measures

    OpenAIRE

    Queiros, Silvio M. Duarte

    2008-01-01

    In this manuscript we present a comparative study about the determination of the relaxation (\\textit{i.e.}, independence) time scales obtained from the correlation function, the mutual information, and a criterion based on the evaluation of a nonextensive generalisation of mutual entropy. Our results show that, for systems with a small degree of complexity, standard mutual information and the criterion based on its nonextensive generalisation provide the same scale, whereas for systems with a...

  6. Scale-Dependent Assessment of Relative Disease Resistance to Plant Pathogens

    Directory of Open Access Journals (Sweden)

    Peter Skelsey

    2014-03-01

    Full Text Available Phenotyping trials may not take into account sufficient spatial context to infer quantitative disease resistance of recommended varieties in commercial production settings. Recent ecological theory—the dispersal scaling hypothesis—provides evidence that host heterogeneity and scale of host heterogeneity interact in a predictable and straightforward manner to produce a unimodal (“humpbacked” distribution of epidemic outcomes. This suggests that the intrinsic artificiality (scale and design of experimental set-ups may lead to spurious conclusions regarding the resistance of selected elite cultivars, due to the failure of experimental efforts to accurately represent disease pressure in real agricultural situations. In this model-based study we investigate the interaction of host heterogeneity and scale as a confounding factor in the inference from ex-situ assessment of quantitative disease resistance to commercial production settings. We use standard modelling approaches in plant disease epidemiology and a number of different agronomic scenarios. Model results revealed that the interaction of heterogeneity and scale is a determinant of relative varietal performance under epidemic conditions. This is a previously unreported phenomenon that could provide a new basis for informing the design of future phenotyping platforms, and optimising the scale at which quantitative disease resistance is assessed.

  7. The total length of myocytes and capillaries, and total number of myocyte nuclei in the rat heart are time-dependently increased by growth hormone

    DEFF Research Database (Denmark)

    Brüel, Annemarie; Oxlund, Hans; Nyengaard, Jens Randel

    2005-01-01

    /kg/day) or vehicle for 5, 10, 20, 40, or 80 days. From the left ventricle (LV) histological sections were made and stereological methods applied. Linear regression showed that GH time-dependently increased: LV volume (r=0.96, P

  8. Synoptic evaluation of scale-dependent metrics for hydrographic line feature geometry

    Science.gov (United States)

    Stanislawski, Larry V.; Buttenfield, Barbara P.; Raposo, Paulo; Cameron, Madeline; Falgout, Jeff T.

    2015-01-01

    Methods of acquisition and feature simplification for vector feature data impact cartographic representations and scientific investigations of these data, and are therefore important considerations for geographic information science (Haunert and Sester 2008). After initial collection, linear features may be simplified to reduce excessive detail or to furnish a reduced-scale version of the features through cartographic generalization (Regnauld and McMaster 2008, Stanislawski et al. 2014). A variety of algorithms exist to simplify linear cartographic features, and all of the methods affect the positional accuracy of the features (Shahriari and Tao 2002, Regnauld and McMaster 2008, Stanislawski et al. 2012). In general, simplification operations are controlled by one or more tolerance parameters that limit the amount of positional change the operation can make to features. Using a single tolerance value can have varying levels of positional change on features; depending on local shape, texture, or geometric characteristics of the original features (McMaster and Shea 1992, Shahriari and Tao 2002, Buttenfield et al. 2010). Consequently, numerous researchers have advocated calibration of simplification parameters to control quantifiable properties of resulting changes to the features (Li and Openshaw 1990, Raposo 2013, Tobler 1988, Veregin 2000, and Buttenfield, 1986, 1989).This research identifies relations between local topographic conditions and geometric characteristics of linear features that are available in the National Hydrography Dataset (NHD). The NHD is a comprehensive vector dataset of surface 18 th ICA Workshop on Generalisation and Multiple Representation, Rio de Janiero, Brazil 2015 2 water features within the United States that is maintained by the U.S. Geological Survey (USGS). In this paper, geometric characteristics of cartographic representations for natural stream and river features are summarized for subbasin watersheds within entire regions of the

  9. Multi-Scale Modeling and Probabilistic Assessment of Electrical Power and Dependent Systems' Resilience to Extreme Events

    Science.gov (United States)

    Backhaus, S.; Pasqualini, D.; Crawford, T.; Ewers, M.; Tasseff, B.; Ambrosiano, J.; Linger, S.; Roberts, R.; Bent, R.; Barnes, A.

    2016-12-01

    Electrical power systems and infrastructure systems that depend on electric power are deployed and operated at spatial scales ranging from individual facilities to cities to regions. The resilience of these systems has evolved naturally under the influence of extreme events. This evolution continues today as systems face more severe and frequent extreme events. Accurately representing the present resilience and future evolution of these systems across such a wide range of scales is both a modeling and computational challenge, especially considering that system evolution may involve new technologies and design approaches where no historical data are available to enable extrapolations. Naïve top-down aggregations of existing electrical power distribution networks will not capture important correlations between previous system hardening and critical dependent systems, leading to inaccurate modeling of current local resilience and costs associated with upgrades to improve local resilience and inaccurate boundary conditions on regional-scale electrical transmission models. Using probabilistic risk analysis approaches for hurricane and ice storm events, we present an integrated multi-scale, multi-sector modeling approach that can model and upscale naturally evolved resilience of fine-scale electrical distribution networks and their dependent critical systems. We use stochastic optimization-based models to predict and upscale potential future evolution driven by existing and emerging technologies. An optimization approach can incorporate human factors and represent potential bias in the resilience adaptation toward different residual risk profiles. We describe the coupling of these new aggregated models of fine-scale electrical power system resilience to models of regional electrical transmission systems and show how resilient regional operational strategies may be adapted to autonomous local resilience upgrades.

  10. Scale-dependency of macroinvertebrate communities: responses to contaminated sediments within run-of-river dams.

    Science.gov (United States)

    Colas, Fanny; Archaimbault, Virginie; Devin, Simon

    2011-03-01

    Due to their nutrient recycling function and their importance in food-webs, macroinvertebrates are essential for the functioning of aquatic ecosystems. These organisms also constitute an important component of biodiversity. Sediment evaluation and monitoring is an essential aspect of ecosystem monitoring since sediments represent an important component of aquatic habitats and are also a potential source of contamination. In this study, we focused on macroinvertebrate communities within run-of-river dams, that are prime areas for sediment and pollutant accumulation. Little is known about littoral macroinvertebrate communities within run-of-river dam or their response to sediment levels and pollution. We therefore aimed to evaluate the following aspects: the functional and structural composition of macroinvertebrate communities in run-of-river dams; the impact of pollutant accumulation on such communities, and the most efficient scales and tools needed for the biomonitoring of contaminated sediments in such environments. Two run-of-river dams located in the French alpine area were selected and three spatial scales were examined: transversal (banks and channel), transversal x longitudinal (banks/channel x tail/middle/dam) and patch scale (erosion, sedimentation and vegetation habitats). At the patch scale, we noted that the heterogeneity of littoral habitats provided many available niches that allow for the development of diversified macroinvertebrate communities. This implies highly variable responses to contamination. Once combined on a global 'banks' spatial scale, littoral habitats can highlight the effects of toxic disturbances. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. The Cultural Dependence of the Ethical Sensitivity Scale Questionnaire: The Case of Iranian Kurdish Teachers

    Directory of Open Access Journals (Sweden)

    Khalil Gholami

    2012-01-01

    Full Text Available A good theory-based tool for measuring ethical sensitivity, which is usable in different contexts, is scarce. In this study, we examined the Ethical Sensitivity Scale Questionnaire (ESSQ in line with its seven-dimension structure. The scale was presented to a sample of 556 Iranian Kurdish teachers in primary, middle, and high schools. A confirmatory factor analysis was conducted to scrutinize the original factor structure of the ESSQ. The results confirmed that the ESSQ supports a reasonable model fit to study the seven dimensions of ethical sensitivity as it was developed in the original study. However, some modifications were conducted to free high error covariance between four pairs of items in the scale. This modification increased the fit indices and thus resulted in a good model fit. In addition to examining the satiability of the ESSQ, a further analysis showed that the level of ethical sensitivity in the targeted sample was high.

  12. Scales

    Science.gov (United States)

    Scales are a visible peeling or flaking of outer skin layers. These layers are called the stratum ... Scales may be caused by dry skin, certain inflammatory skin conditions, or infections. Examples of disorders that ...

  13. Defect evolution in cosmology and condensed matter quantitative analysis with the velocity-dependent one-scale model

    CERN Document Server

    Martins, C J A P

    2016-01-01

    This book sheds new light on topological defects in widely differing systems, using the Velocity-Dependent One-Scale Model to better understand their evolution. Topological defects – cosmic strings, monopoles, domain walls or others - necessarily form at cosmological (and condensed matter) phase transitions. If they are stable and long-lived they will be fossil relics of higher-energy physics. Understanding their behaviour and consequences is a key part of any serious attempt to understand the universe, and this requires modelling their evolution. The velocity-dependent one-scale model is the only fully quantitative model of defect network evolution, and the canonical model in the field. This book provides a review of the model, explaining its physical content and describing its broad range of applicability.

  14. Zooming in and out: scale dependence of extrinsic and intrinsic factors affecting salt marsh erosion

    NARCIS (Netherlands)

    Wang, H.; van der Wal, D.; Li, X.; van Belzen, J.; Herman, P.M.J.; Hu, Z.; Ge, Z.; Zhang, L.; Bouma, T.J.

    2017-01-01

    Salt marshes are valuable ecosystems that provide important ecosystem services. Given the global scale of marsh loss due to climate change and coastal squeeze, there is a pressing need to identify the critical extrinsic (wind exposure and foreshore morphology) and intrinsic factors (soil and

  15. The spatial scale dependence of water vapor variability inferred from observations from a very tall tower

    Science.gov (United States)

    Pressel, Kyle G.; Collins, William D.; Desai, Ankur R.

    2014-08-01

    Recent studies have established that atmospheric water vapor fields exhibit spatial spectra that take the form of power laws and hence can be compactly characterized by scaling exponents. The power law scaling exponents have been shown to exhibit substantial vertical variability. In this work, Taylor's frozen turbulence hypothesis is used to infer the first-order spatial structure function and generalized detrended fluctuation function scaling exponents for scales between 1 km and 100 km. Both methods are used to estimate the Hurst exponent (H) using 10 Hz time series of water vapor measured at 396 m altitude from an Ameriflux tower in Wisconsin. Due to the diurnal cycle in the boundary layer height at the 396 m observational level, H may be estimated for both the daytime convective mixed layer and the nocturnal residual layer. Values of H≈13 are obtained for the convective mixed layer, while values of H>12 apply in the nocturnal residual layer. The results are shown to be remarkably consistent with a similar analysis from satellite-based observations as reported in Pressel and Collins (2012).

  16. Scale-dependent genetic structure of the Idaho giant salamander (Dicamptodon aterrimus) in stream networks

    Science.gov (United States)

    Lindy B. Mullen; H. Arthur Woods; Michael K. Schwartz; Adam J. Sepulveda; Winsor H. Lowe

    2010-01-01

    The network architecture of streams and rivers constrains evolutionary, demographic and ecological processes of freshwater organisms. This consistent architecture also makes stream networks useful for testing general models of population genetic structure and the scaling of gene flow. We examined genetic structure and gene flow in the facultatively paedomorphic Idaho...

  17. Musicians demonstrate experience-dependent brainstem enhancement of musical scale features within continuously gliding pitch.

    Science.gov (United States)

    Bidelman, Gavin M; Gandour, Jackson T; Krishnan, Ananthanarayan

    2011-10-10

    In contrast to language, where pitch patterns consist of continuous and curvilinear contours, musical pitch consists of relatively discrete, stair-stepped sequences of notes. Behavioral and neurophysiological studies suggest that both tone-language and music experience enhance the representation of pitch cues associated with a listener's domain of expertise, e.g., curvilinear pitch in language, discrete scale steps in music. We compared brainstem frequency-following responses (FFRs) of English-speaking musicians (musical pitch experience) and native speakers of Mandarin Chinese (linguistic pitch experience) elicited by rising and falling tonal sweeps that are exemplary of Mandarin tonal contours but uncharacteristic of the pitch patterns typically found in music. In spite of musicians' unfamiliarity with such glides, we find that their brainstem FFRs show enhancement of the stimulus where the curvilinear sweep traverses discrete notes along the diatonic musical scale. This enhancement was note specific in that it was not observed immediately preceding or following the scale tone of interest (passing note). No such enhancements were observed in Chinese listeners. These findings suggest that the musician's brainstem may be differentially tuned by long-term exposure to the pitch patterns inherent to music, extracting pitch in relation to a fixed, hierarchical scale. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. A bodyweight-dependent allometric exponent for scaling clearance across the human life-span

    NARCIS (Netherlands)

    C. Wang (Chenguang); M.Y. Peeters (Mariska); K.M. Allegaert (Karel); H.J. Blussé van Oud-Alblas (Heleen); E.H.J. Krekels (Elke); D. Tibboel (Dick); M. Danhof (Meindert); C.A.J. Knibbe (Catherijne)

    2012-01-01

    textabstractPurpose: To explore different allometric equations for scaling clearance across the human life-span using propofol as a model drug. Methods: Data from seven previously published propofol studies ((pre)term neonates, infants, toddlers, children, adolescents and adults) were analysed using

  19. A synthesis of scale-dependent ecology of the endangered mountain caribou in British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    Robert Serrouya

    2008-06-01

    Full Text Available Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou that live in highprecipitation, mountainous ecosystems of southeastern British Columbia and northern Idaho. The distribution and abundance of these caribou have declined dramatically from historical figures. Results from many studies have indicated that mountain caribou rely on old conifer forests for several life-history requirements including an abundance of their primary winter food, arboreal lichen, and a scarcity of other ungulates and their predators. These old forests often have high timber value, and understanding mountain caribou ecology at a variety of spatial scales is thus required to develop effective conservation strategies. Here we summarize results of studies conducted at three different spatial scales ranging from broad limiting factors at the population level to studies describing the selection of feeding sites within seasonal home ranges of individuals. The goal of this multi-scale review is to provide a more complete picture of caribou ecology and to determine possible shifts in limiting factors across scales. Our review produced two important results. First, mountain caribou select old forests and old trees at all spatial scales, signifying their importance for foraging opportunities as well as conditions required to avoid alternate ungulates and their predators. Second, relationships differ across scales. For example, landscapes dominated by roads and edges negatively affect caribou survival, but appear to attract caribou during certain times of the year. This juxtaposition of fine-scale behaviour with broad-scale vulnerability to predation could only be identified through integrated multi-scale analyses of resource selection. Consequently we suggest that effective management strategies for endangered species require an integrative approach across multiple spatial scales to avoid a focus that may be too narrow to maintain viable

  20. Scale-dependent environmental control of mesozooplankton community structure in three aquaculture subtropical bays of China

    Directory of Open Access Journals (Sweden)

    Dong Sun

    2016-04-01

    Full Text Available Most subtropical bays of China have been under heavy pollution since the late 1990s, mainly because of the rapid development of aquaculture and discharge of industrial and agricultural wastewater. Some projects were conducted to investigate the zooplankton community in these bays, but those studies were less focused on the relationship between spatial structure of mesozooplankton community and environmental variables in/among bays. The mesozooplankton community structures in relation to physical, chemical and biological variables were studied in three subtropical bays of China with seasons and different spatial scales during 2000 and 2002–2003. Data were collected on temperature (T, salinity (S, concentration of chlorophyll a (Chl a, pH, dissolved oxygen (DO, soluble reactive phosphate (SRP, dissolved inorganic nitrogen (DIN, chemical oxygen demand (COD, suspended particle material (SPM and mesozooplankton taxonomic abundances. Correlation analysis showed that the main environmental factors correlated to the total abundance of mesozooplankton in these subtropical bays were Chl a, temperature, COD and SRP. Multivariate analysis indicated that DO, Chl a and temperature were the principal factors in influencing spatial differentiation of zooplankton community structure in the inter-bay scale. At the within-bay scale, the influencing factors were different among bays; the main factors were physical variables for Xiangshan Bay and Sanmen Bay, while chemical variables for Yueqing Bay, respectively. The results revealed that the environmental variables that affected spatial structure of mesozooplankton community were different at inter-bay scale and within-bay scales, and zooplankton community was more influenced by chemical (e.g. nutrients/ammonia variables when under serious eutrophication condition, while it would be more influenced by physical variables (temperature/salinity when under less eutrophic conditions.

  1. Assessments of habitat preferences and quality depend on spatial scale and metrics of fitness

    Science.gov (United States)

    Chalfoun, A.D.; Martin, T.E.

    2007-01-01

    1. Identifying the habitat features that influence habitat selection and enhance fitness is critical for effective management. Ecological theory predicts that habitat choices should be adaptive, such that fitness is enhanced in preferred habitats. However, studies often report mismatches between habitat preferences and fitness consequences across a wide variety of taxa based on a single spatial scale and/or a single fitness component. 2. We examined whether habitat preferences of a declining shrub steppe songbird, the Brewer's sparrow Spizella breweri, were adaptive when multiple reproductive fitness components and spatial scales (landscape, territory and nest patch) were considered. 3. We found that birds settled earlier and in higher densities, together suggesting preference, in landscapes with greater shrub cover and height. Yet nest success was not higher in these landscapes; nest success was primarily determined by nest predation rates. Thus landscape preferences did not match nest predation risk. Instead, nestling mass and the number of nesting attempts per pair increased in preferred landscapes, raising the possibility that landscapes were chosen on the basis of food availability rather than safe nest sites. 4. At smaller spatial scales (territory and nest patch), birds preferred different habitat features (i.e. density of potential nest shrubs) that reduced nest predation risk and allowed greater season-long reproductive success. 5. Synthesis and applications. Habitat preferences reflect the integration of multiple environmental factors across multiple spatial scales, and individuals may have more than one option for optimizing fitness via habitat selection strategies. Assessments of habitat quality for management prescriptions should ideally include analysis of diverse fitness consequences across multiple ecologically relevant spatial scales. ?? 2007 The Authors.

  2. Queue Length and Server Content Distribution in an Infinite-Buffer Batch-Service Queue with Batch-Size-Dependent Service

    Directory of Open Access Journals (Sweden)

    U. C. Gupta

    2015-01-01

    Full Text Available We analyze an infinite-buffer batch-size-dependent batch-service queue with Poisson arrival and arbitrarily distributed service time. Using supplementary variable technique, we derive a bivariate probability generating function from which the joint distribution of queue and server content at departure epoch of a batch is extracted and presented in terms of roots of the characteristic equation. We also obtain the joint distribution of queue and server content at arbitrary epoch. Finally, the utility of analytical results is demonstrated by the inclusion of some numerical examples which also includes the investigation of multiple zeros.

  3. DNA-length-dependent quenching of fluorescently labeled iron oxide nanoparticles with gold, graphene oxide and MoS2 nanostructures.

    Science.gov (United States)

    Balcioglu, Mustafa; Rana, Muhit; Robertson, Neil; Yigit, Mehmet V

    2014-08-13

    We controlled the fluorescence emission of a fluorescently labeled iron oxide nanoparticle using three different nanomaterials with ultraefficient quenching capabilities. The control over the fluorescence emission was investigated via spacing introduced by the surface-functionalized single-stranded DNA molecules. DNA molecules were conjugated on different templates, either on the surface of the fluorescently labeled iron oxide nanoparticles or gold and nanographene oxide. The efficiency of the quenching was determined and compared with various fluorescently labeled iron oxide nanoparticle and nanoquencher combinations using DNA molecules with three different lengths. We have found that the template for DNA conjugation plays significant role on quenching the fluorescence emission of the fluorescently labeled iron oxide nanoparticles. We have observed that the size of the DNA controls the quenching efficiency when conjugated only on the fluorescently labeled iron oxide nanoparticles by setting a spacer between the surfaces and resulting change in the hydrodynamic size. The quenching efficiency with 12mer, 23mer and 36mer oligonucleotides decreased to 56%, 54% and 53% with gold nanoparticles, 58%, 38% and 32% with nanographene oxide, 46%, 38% and 35% with MoS2, respectively. On the other hand, the presence, not the size, of the DNA molecules on the other surfaces quenched the fluorescence significantly with different degrees. To understand the effect of the mobility of the DNA molecules on the nanoparticle surface, DNA molecules were attached to the surface with two different approaches. Covalently immobilized oligonucleotides decreased the quenching efficiency of nanographene oxide and gold nanoparticles to ∼22% and ∼21%, respectively, whereas noncovalently adsorbed oligonucleotides decreased it to ∼25% and ∼55%, respectively. As a result, we have found that each nanoquencher has a powerful quenching capability against a fluorescent nanoparticle, which can be

  4. Plant diversity increases with the strength of negative density dependence at the global scale

    Science.gov (United States)

    Joseph A. LaManna; Scott A. Mangan; Alfonso Alonso; Norman A. Bourg; Warren Y. Brockelman; Sarayudh Bunyavejchewin; Li-Wan Chang; Jyh-Min Chiang; George B. Chuyong; Keith Clay; Richard Condit; Susan Cordell; Stuart J. Davies; Tucker J. Furniss; Christian P. Giardina; I. A. U. Nimal Gunatilleke; C. V. Savitri Gunatilleke; Fangliang He; Robert W. Howe; Stephen P. Hubbell; Chang-Fu Hsieh; Faith M. Inman-Narahari; David Janík; Daniel J. Johnson; David Kenfack; Lisa Korte; Kamil Král; Andrew J. Larson; James A. Lutz; Sean M. McMahon; William J. McShea; Hervé R. Memiaghe; Anuttara Nathalang; Vojtech Novotny; Perry S. Ong; David A. Orwig; Rebecca Ostertag; Geoffrey G. Parker; Richard P. Phillips; Lawren Sack; I-Fang Sun; J. Sebastián Tello; Duncan W. Thomas; Benjamin L. Turner; Dilys M. Vela Díaz; Tomáš Vrška; George D. Weiblen; Amy Wolf; Sandra Yap; Jonathan A. Myers

    2017-01-01

    Theory predicts that higher biodiversity in the tropics is maintained by specialized interactions among plants and their natural enemies that result in conspecific negative density dependence (CNDD). By using more than 3000 species and nearly 2.4 million trees across 24 forest plots worldwide, we show that global patterns in tree species diversity reflect not only...

  5. Large-Scale Profiling of Kinase Dependencies in Cancer Cell Lines.

    Science.gov (United States)

    Campbell, James; Ryan, Colm J; Brough, Rachel; Bajrami, Ilirjana; Pemberton, Helen N; Chong, Irene Y; Costa-Cabral, Sara; Frankum, Jessica; Gulati, Aditi; Holme, Harriet; Miller, Rowan; Postel-Vinay, Sophie; Rafiq, Rumana; Wei, Wenbin; Williamson, Chris T; Quigley, David A; Tym, Joe; Al-Lazikani, Bissan; Fenton, Timothy; Natrajan, Rachael; Strauss, Sandra J; Ashworth, Alan; Lord, Christopher J

    2016-03-15

    One approach to identifying cancer-specific vulnerabilities and therapeutic targets is to profile genetic dependencies in cancer cell lines. Here, we describe data from a series of siRNA screens that identify the kinase genetic dependencies in 117 cancer cell lines from ten cancer types. By integrating the siRNA screen data with molecular profiling data, including exome sequencing data, we show how vulnerabilities/genetic dependencies that are associated with mutations in specific cancer driver genes can be identified. By integrating additional data sets into this analysis, including protein-protein interaction data, we also demonstrate that the genetic dependencies associated with many cancer driver genes form dense connections on functional interaction networks. We demonstrate the utility of this resource by using it to predict the drug sensitivity of genetically or histologically defined subsets of tumor cell lines, including an increased sensitivity of osteosarcoma cell lines to FGFR inhibitors and SMAD4 mutant tumor cells to mitotic inhibitors. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Large-Scale Profiling of Kinase Dependencies in Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    James Campbell

    2016-03-01

    Full Text Available One approach to identifying cancer-specific vulnerabilities and therapeutic targets is to profile genetic dependencies in cancer cell lines. Here, we describe data from a series of siRNA screens that identify the kinase genetic dependencies in 117 cancer cell lines from ten cancer types. By integrating the siRNA screen data with molecular profiling data, including exome sequencing data, we show how vulnerabilities/genetic dependencies that are associated with mutations in specific cancer driver genes can be identified. By integrating additional data sets into this analysis, including protein-protein interaction data, we also demonstrate that the genetic dependencies associated with many cancer driver genes form dense connections on functional interaction networks. We demonstrate the utility of this resource by using it to predict the drug sensitivity of genetically or histologically defined subsets of tumor cell lines, including an increased sensitivity of osteosarcoma cell lines to FGFR inhibitors and SMAD4 mutant tumor cells to mitotic inhibitors.

  7. Mapping condition-dependent regulation of metabolism in yeast through genome-scale modeling

    DEFF Research Database (Denmark)

    Österlund, Tobias; Nookaew, Intawat; Bordel, Sergio

    2013-01-01

    ABSTRACT: BACKGROUND: The genome-scale metabolic model of Saccharomyces cerevisiae, first presented in 2003, was the first genome-scale network reconstruction for a eukaryotic organism. Since then continuous efforts have been made in order to improve and expand the yeast metabolic network. RESULTS......-filling methods and by introducing new reactions and pathways based on studies of the literature and databases. The model was shown to perform well both for growth simulations in different media and gene essentiality analysis for single and double knock-outs. Further, the model was used as a scaffold......-to-date collection of knowledge on yeast metabolism. The model was used for simulating the yeast metabolism under four different growth conditions and experimental data from these four conditions was integrated to the model. The model together with experimental data is a useful tool to identify condition...

  8. Sex-biased dispersal patterns depend on the spatial scale in a social rodent

    Science.gov (United States)

    Gauffre, B.; Petit, E.; Brodier, S.; Bretagnolle, V.; Cosson, J. F.

    2009-01-01

    Dispersal is a fundamental process in ecology because it influences the dynamics, genetic structure and persistence of populations. Furthermore, understanding the evolutionary causes of dispersal pattern, particularly when they differ between genders, is still a major question in evolutionary ecology. Using a panel of 10 microsatellite loci, we investigated at different spatial scales the genetic structure and the sex-specific dispersal patterns in the common vole Microtus arvalis, a small colonial mammal. This study was conducted in an intensive agricultural area of western France. Hierarchical FST analyses, relatedness and assignment tests suggested (i) that females are strongly kin-clustered within colonies; (ii) that dispersal is strongly male-biased at a local scale; and (iii) long-distance dispersal is not rare and more balanced between genders. We conclude that males migrate continuously from colony to colony to reproduce, whereas females may disperse just once and would be mainly involved in new colony foundation. PMID:19586945

  9. Detrended fluctuation analysis as a regression framework: Estimating dependence at different scales

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav

    2015-01-01

    Roč. 91, č. 1 (2015), 022802-1-022802-5 ISSN 1539-3755 R&D Projects: GA ČR(CZ) GP14-11402P Grant - others:GA ČR(CZ) GAP402/11/0948 Program:GA Institutional support: RVO:67985556 Keywords : Detrended cross-correlation analysis * Regression * Scales Subject RIV: AH - Economics Impact factor: 2.288, year: 2014 http://library.utia.cas.cz/separaty/2015/E/kristoufek-0452315.pdf

  10. Scale dependency in the hydromorphological control of a stream ecosystem functioning.

    Science.gov (United States)

    Colas, Fanny; Baudoin, Jean-Marc; Gob, Frédéric; Tamisier, Vincent; Valette, Laurent; Kreutzenberger, Karl; Lambrigot, Didier; Chauvet, Eric

    2017-05-15

    Physical habitat degradation is prevalent in river ecosystems. Although still little is known about the ecological consequences of altered hydromorphology, understanding the factors at play can contribute to sustainable environmental management. In this study we aimed to identify the hydromorphological features controlling a key ecosystem function and the spatial scales where such linkages operate. As hydromorphological and chemical pressures often occur in parallel, we examined the relative importance of hydromorphological and chemical factors as determinants of leaf breakdown. Leaf breakdown assays were investigated at 82 sites of rivers throughout the French territory. Leaf breakdown data were then crossed with data on water quality and with a multi-scale hydromorphological assessment (i.e. upstream catchment, river segment, reach and habitat) when quantitative data were available. Microbial and total leaf breakdown rates exhibited differential responses to both hydromorphological and chemical alterations. Relationships between the chemical quality of the water and leaf breakdown were weak, while hydromorphological integrity explained independently up to 84.2% of leaf breakdown. Hydrological and morphological parameters were the main predictors of microbial leaf breakdown, whereas hydrological parameters had a major effect on total leaf breakdown, particularly at large scales, while morphological parameters were important at smaller scales. Microbial leaf breakdown were best predicted by hydromorphological features defined at the upstream catchment level whereas total leaf breakdown were best predicted by reach and habitat level geomorphic variables. This study demonstrates the use of leaf breakdown in a biomonitoring context and the importance of hydromorphological integrity for the functioning of running water. It provides new insights for environmental decision-makers to identify the management and restoration actions that have to be undertaken including the

  11. Ionosphere fluctuations and global indices: A scale dependent wavelet-based cross-correlation analysis

    Czech Academy of Sciences Publication Activity Database

    Roux, S. G.; Knížová, Petra; Mošna, Zbyšek; Abry, P.

    90-91, Special Issue (2012), s. 186-197 ISSN 1364-6826 Institutional support: RVO:68378289 Keywords : cross-correlation * F-layer * Fof2-measurements * geomagnetic activity * global indices * ionosphere * scale invariance * solar activity Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 1.417, year: 2012 https://www.sciencedirect.com/science/article/pii/S1364682612000983

  12. Scale dependent behavioral responses to human development by a large predator, the puma.

    Science.gov (United States)

    Wilmers, Christopher C; Wang, Yiwei; Nickel, Barry; Houghtaling, Paul; Shakeri, Yasaman; Allen, Maximilian L; Kermish-Wells, Joe; Yovovich, Veronica; Williams, Terrie

    2013-01-01

    The spatial scale at which organisms respond to human activity can affect both ecological function and conservation planning. Yet little is known regarding the spatial scale at which distinct behaviors related to reproduction and survival are impacted by human interference. Here we provide a novel approach to estimating the spatial scale at which a top predator, the puma (Puma concolor), responds to human development when it is moving, feeding, communicating, and denning. We find that reproductive behaviors (communication and denning) require at least a 4× larger buffer from human development than non-reproductive behaviors (movement and feeding). In addition, pumas give a wider berth to types of human development that provide a more consistent source of human interference (neighborhoods) than they do to those in which human presence is more intermittent (arterial roads with speeds >35 mph). Neighborhoods were a deterrent to pumas regardless of behavior, while arterial roads only deterred pumas when they were communicating and denning. Female pumas were less deterred by human development than males, but they showed larger variation in their responses overall. Our behaviorally explicit approach to modeling animal response to human activity can be used as a novel tool to assess habitat quality, identify wildlife corridors, and mitigate human-wildlife conflict.

  13. Voxel Scale Complex Networks of Functional Connectivity in the Rat Brain: Neurochemical State Dependence of Global and Local Topological Properties

    Directory of Open Access Journals (Sweden)

    Adam J. Schwarz

    2012-01-01

    Full Text Available Network analysis of functional imaging data reveals emergent features of the brain as a function of its topological properties. However, the brain is not a homogeneous network, and the dependence of functional connectivity parameters on neuroanatomical substrate and parcellation scale is a key issue. Moreover, the extent to which these topological properties depend on underlying neurochemical changes remains unclear. In the present study, we investigated both global statistical properties and the local, voxel-scale distribution of connectivity parameters of the rat brain. Different neurotransmitter systems were stimulated by pharmacological challenge (d-amphetamine, fluoxetine, and nicotine to discriminate between stimulus-specific functional connectivity and more general features of the rat brain architecture. Although global connectivity parameters were similar, mapping of local connectivity parameters at high spatial resolution revealed strong neuroanatomical dependence of functional connectivity in the rat brain, with clear differentiation between the neocortex and older brain regions. Localized foci of high functional connectivity independent of drug challenge were found in the sensorimotor cortices, consistent with the high neuronal connectivity in these regions. Conversely, the topological properties and node roles in subcortical regions varied with neurochemical state and were dependent on the specific dynamics of the different functional processes elicited.

  14. Modeling of scale-dependent bacterial growth by chemical kinetics approach.

    Science.gov (United States)

    Martínez, Haydee; Sánchez, Joaquín; Cruz, José-Manuel; Ayala, Guadalupe; Rivera, Marco; Buhse, Thomas

    2014-01-01

    We applied the so-called chemical kinetics approach to complex bacterial growth patterns that were dependent on the liquid-surface-area-to-volume ratio (SA/V) of the bacterial cultures. The kinetic modeling was based on current experimental knowledge in terms of autocatalytic bacterial growth, its inhibition by the metabolite CO2, and the relief of inhibition through the physical escape of the inhibitor. The model quantitatively reproduces kinetic data of SA/V-dependent bacterial growth and can discriminate between differences in the growth dynamics of enteropathogenic E. coli, E. coli JM83, and Salmonella typhimurium on one hand and Vibrio cholerae on the other hand. Furthermore, the data fitting procedures allowed predictions about the velocities of the involved key processes and the potential behavior in an open-flow bacterial chemostat, revealing an oscillatory approach to the stationary states.

  15. RADIAL DEPENDENCE OF THE FREQUENCY BREAK BETWEEN FLUID AND KINETIC SCALES IN THE SOLAR WIND FLUCTUATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, R.; Trenchi, L., E-mail: roberto.bruno@iaps.inaf.it [INAF-IAPS Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, 00133 Roma (Italy)

    2014-06-01

    We investigate the radial dependence of the spectral break separating the inertial from the dissipation range in power density spectra of interplanetary magnetic field fluctuations, between 0.42 and 5.3 AU, during radial alignments between MESSENGER and WIND for the inner heliosphere and between WIND and ULYSSES for the outer heliosphere. We found that the spectral break moves to higher and higher frequencies as the heliocentric distance decreases. The radial dependence of the corresponding wavenumber is of the kind κ {sub b} ∼ R {sup –1.08}, in good agreement with that of the wavenumber derived from the linear resonance condition for proton cyclotron damping. These results support conclusions from previous studies which suggest that a cyclotron-resonant dissipation mechanism must participate in the spectral cascade together with other possible kinetic noncyclotron-resonant mechanisms.

  16. ROS-activated ATM-dependent phosphorylation of cytoplasmic substrates identified by large scale phosphoproteomics screen

    DEFF Research Database (Denmark)

    Kozlov, Sergei V; Waardenberg, Ashley J; Engholm-Keller, Kasper

    2016-01-01

    checkpoints, initiating DNA repair and regulating gene expression. ATM kinase can be activated by a variety of stimuli, including oxidative stress. Here we confirmed activation of cytoplasmic ATM by autophosphorylation at multiple sites. Then we employed a global quantitative phosphoproteomics approach...... to identify cytoplasmic proteins altered in their phosphorylation state in control and A-T (ataxia-telangiectasia) cells in response to oxidative damage. We demonstrated that ATM was activated by oxidative damage in the cytoplasm as well as in the nucleus and identified a total of 9,833 phosphorylation sites......-dependent after H2O2 exposure and another protein (S100A11) demonstrated ATM-dependence for translocation from the cytoplasm to the nucleus. These data provide new insights into the activation of ATM by oxidative stress through identification of novel substrates for ATM in the cytoplasm. 2....

  17. Molecular statics study of depth-dependent hysteresis in nano-scale adhesive elastic contacts

    Science.gov (United States)

    Deng, Weilin; Kesari, Haneesh

    2017-07-01

    The contact force—indentation-depth (P-h) measurements in adhesive contact experiments, such as atomic force microscopy, display hysteresis. In some cases, the amount of hysteretic energy loss is found to depend on the maximum indentation-depth. This depth-dependent hysteresis (DDH) is not explained by classical contact theories, such as Johnson-Kendall-Roberts and Derjaguin-Muller-Toporov, and is often attributed to surface moisture, material viscoelasticity, and plasticity. We present molecular statics simulations that are devoid of these mechanisms, yet still capture DDH. In our simulations, DDH is due to a series of surface mechanical instabilities. Surface features, such as depressions or protrusions, can temporarily arrest the growth or recession of the contact area. With a sufficiently large change of indentation-depth, the contact area grows or recedes abruptly by a finite amount and dissipates energy. This is similar to the pull-in and pull-off instabilities in classical contact theories, except that in this case the number of instabilities depends on the roughness of the contact surface. Larger maximum indentation-depths result in more surface features participating in the load-unload process, resulting in larger hysteretic energy losses. This mechanism is similar to the one recently proposed by one of the authors using a continuum mechanics-based model. However, that model predicts that the hysteretic energy loss always increases with roughness, whereas experimentally it is found that the hysteretic energy loss initially increases but then later decreases with roughness. Our simulations capture this non-monotonic dependence of hysteretic energy loss on roughness.