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1

Laminar-turbulent transition in a bayonet tube  

Microsoft Academic Search

This paper provides the details of a numerical study of the bayonet tube during the laminar-turbulent transition. Attention is focused on the frictional characteristics of the tube. The results constitute a systematic investigation of the effect of the principal parameters on hydraulic resistance represented by an Euler number. Specifically discussed are the effects of fluid properties, tube length, and inner

Harpal Minhas; G. S. H. Lock

1996-01-01

2

Laminar-turbulent cycles in inclined lock-exchange flows  

NASA Astrophysics Data System (ADS)

We consider strongly confined, stably stratified shear flows generated as a lock exchange in a tube inclined at an angle of ?=45?. This paper focuses on a transitional regime, in which the flow alternates between two distinct states: laminar, parallel shear flow and intense transverse motion characteristic of turbulence. Laminar-turbulent cycles were captured at Atwood numbers At?(?2-?1)/(?1+?2) ranging from 2.45×10-3 to 4.0×10-3, where (?1,?2) are the initial densities of the two fluids, with multiple cycles observed at At=2.55×10-3. The evolution of the density and velocity fields in these flows was measured simultaneously using laser-induced fluorescence and particle image velocimetry. During each laminar-turbulent cycle, the axial velocity exhibits a distinctive ramp-cliff pattern, indicating that the flow accelerates as it relaminarizes, then decelerates rapidly as the Kelvin-Helmholtz billows break down. Within the range of experimental conditions, transverse stratification does not directly determine the onset of instability. Instead, the data suggest that a necessary criterion for the onset of instability is for the local Reynolds number to exceed 2200, with only a weak dependence on the Richardson number.

Tanino, Yukie; Moisy, Frédéric; Hulin, Jean-Pierre

2012-06-01

3

Laminar-turbulent cycles in inclined lock-exchange flows.  

PubMed

We consider strongly confined, stably stratified shear flows generated as a lock exchange in a tube inclined at an angle of ?=45(?). This paper focuses on a transitional regime, in which the flow alternates between two distinct states: laminar, parallel shear flow and intense transverse motion characteristic of turbulence. Laminar-turbulent cycles were captured at Atwood numbers At?(?(2)-?(1))/(?(1)+?(2)) ranging from 2.45×10(-3) to 4.0×10(-3), where (?(1),?(2)) are the initial densities of the two fluids, with multiple cycles observed at At=2.55×10(-3). The evolution of the density and velocity fields in these flows was measured simultaneously using laser-induced fluorescence and particle image velocimetry. During each laminar-turbulent cycle, the axial velocity exhibits a distinctive ramp-cliff pattern, indicating that the flow accelerates as it relaminarizes, then decelerates rapidly as the Kelvin-Helmholtz billows break down. Within the range of experimental conditions, transverse stratification does not directly determine the onset of instability. Instead, the data suggest that a necessary criterion for the onset of instability is for the local Reynolds number to exceed 2200, with only a weak dependence on the Richardson number. PMID:23005207

Tanino, Yukie; Moisy, Frédéric; Hulin, Jean-Pierre

2012-06-11

4

Forced convection in an air-filled bayonet tube during the laminar-turbulent transition  

Microsoft Academic Search

The paper provides details of a numerical study of the bayonet tube during the laminar turbulent transition when the fluid is air. Attention is focused on the heat transfer characteristics of the tube. The data constitute a systematic investigation of the effect of several parameters on the overall heat transfer rate, represented by a Nusselt number. Specifically discussed are the

Harpal Minhas; G. S. H. Lock

1997-01-01

5

The laminar-turbulent transition in a fibre laser  

NASA Astrophysics Data System (ADS)

Studying the transition from a linearly stable coherent laminar state to a highly disordered state of turbulence is conceptually and technically challenging, and of great interest because all pipe and channel flows are of that type. In optics, understanding how a system loses coherence, as spatial size or the strength of excitation increases, is a fundamental problem of practical importance. Here, we report our studies of a fibre laser that operates in both laminar and turbulent regimes. We show that the laminar phase is analogous to a one-dimensional coherent condensate and the onset of turbulence is due to the loss of spatial coherence. Our investigations suggest that the laminar-turbulent transition in the laser is due to condensate destruction by clustering dark and grey solitons. This finding could prove valuable for the design of coherent optical devices as well as systems operating far from thermodynamic equilibrium.

Turitsyna, E. G.; Smirnov, S. V.; Sugavanam, S.; Tarasov, N.; Shu, X.; Babin, S. A.; Podivilov, E. V.; Churkin, D. V.; Falkovich, G.; Turitsyn, S. K.

2013-10-01

6

Comparison of several models of the laminar/turbulent transition  

NASA Astrophysics Data System (ADS)

The contribution deals with modelling of the laminar/turbulent transition using several transition models. Transition models of various types were tested: a) the model with the algebraic equation for the intermittency coefficient according to Straka and Pøíhoda; b) the three-equation transition model with the transport equation for the energy of non-turbulent fluctuations proposed by Walters and Cokljat; c) the ?-Re? model with the transport equation forthe intermittency coefficient of Langtry and Menter. The transition models were compared by means of test cases covering both flat-plate boundary-layer flows with various free stream turbulence and the flow over an airfoil including the effect of foregoing wake on the transition. The agreement of numerical results with experimental data is in all cases quite satisfactory.

Fürst, V.; Straka, J.; P?íhoda, P.; Šimurda, J.

2013-04-01

7

Identification of the laminar-turbulent transition process in a plasma plume  

Microsoft Academic Search

This paper illustrates the complete dynamics of the laminar-turbulent transition process in a plasma plume using a simple measurement of the magnation-point heat flux correlated with acoustic, optical, and voltage drop fluctuations. In the laminar flow regime a steady jet is produced and the heat fluxes are accurately predicted hr laminar correlations. The initial stage of transition is characterized by

L. Krejci; V. Dolinek; B. Ruzicka; V. Chalupova; S. Russ

1993-01-01

8

Development of Quiet-Flow Supersonic Wind Tunnels for Laminar-Turbulent Transition Research.  

National Technical Information Service (NTIS)

This grant supported research into quiet-flow supersonic wind-tunnels, between May 1990 and December 1994. Quiet-flow nozzles operate with laminar nozzle-wall boundary layers, in order to provide low-disturbance flow for studies of laminar-turbulent trans...

S. P. Schneider

1994-01-01

9

Problems of the laminar-turbulent boundary layer transition - Physics and prediction  

NASA Astrophysics Data System (ADS)

The paper presents a survey of laminar-turbulent transition problems for 2D and 3D flows, both incompressible and compressible. Receptivity mechanisms and linear and nonlinear stability phenomena are considered. Attention is given to various examples of the application of the exp n method, which provides an estimate of the transition position.

Arnal, D.

10

Nature of laminar-turbulence intermittency in shear flows.  

PubMed

In pipe, channel, and boundary layer flows turbulence first occurs intermittently in space and time: at moderate Reynolds numbers domains of disordered turbulent motion are separated by quiescent laminar regions. Based on direct numerical simulations of pipe flow we argue here that the spatial intermittency has its origin in a nearest neighbor interaction between turbulent regions. We further show that in this regime turbulent flows are intrinsically intermittent with a well-defined equilibrium turbulent fraction but without ever assuming a steady pattern. This transition scenario is analogous to that found in simple models such as coupled map lattices. The scaling observed implies that laminar intermissions of the turbulent flow will persist to arbitrarily large Reynolds numbers. PMID:23848777

Avila, M; Hof, B

2013-06-18

11

Evaluation of laminar-turbulent transition and equilibrium near wall turbulence models  

SciTech Connect

Accurate prediction of laminar-turbulent transition as well as fully turbulent flows is of much practical importance. In this study, both topics are investigated. The e{sup n} method is used to predict transition locations for flows with various angles of attack around on NACA 0012 airfoil. After the transition point the {kappa}-{epsilon} turbulence model is adopted. Computations for flow over a flat plate are done to understand the impact of grid distribution and the wall function treatment on the performance of the {kappa}-{epsilon} turbulence model. In attached and mildly separated flows, satisfactory predictions can be made with the pragmatic e{sup n} transition model and the {kappa}-{epsilon} turbulence model.

He, X.; Senocak, I.; Shyy, W.; Gangadharan, S.N.; Thakur, S.

2000-02-11

12

On the growth of laminar-turbulent patterns in plane Couette flow  

NASA Astrophysics Data System (ADS)

The growth of laminar-turbulent band patterns in plane Couette flow is studied in the vicinity of the global stability threshold Reg below which laminar flow ultimately prevails. Appropriately tailored direct numerical simulations are performed to manage systems extended enough to accommodate several bands. The initial state or germ is an oblique turbulent patch of limited extent. The growth is seen to result from several competing processes: (i) nucleation of turbulent patches close to or at the extremities of already formed band segments, with the same obliquity as the germ or the opposite one, and (ii) turbulence collapse similar to gap formation for band decay. Growth into a labyrinthine pattern is observed as soon as spanwise expansion is effective. An ideally aligned pattern is usually obtained at the end of a long and gradual regularization stage when Re is large enough. Stable isolated bands can be observed slightly above Reg. When growth rates are not large enough, the germ decays at the end of a long transient, similarly to what was observed in experiments. Local continuous growth/decay microscopic mechanisms are seen to compete with large deviations which are the cause of mesoscopic nucleation events (turbulent patches or laminar gaps) controlling the macroscopic behaviour of the system (pattern). The implications of these findings are discussed in the light of Pomeau's proposals based on directed percolation and first-order phase transitions in statistical physics.

Manneville, Paul

2012-06-01

13

On active control of laminar-turbulent transition on two-dimensional wings.  

PubMed

This paper gives an overview of drag reduction on aerofoils by means of active control of Tollmien-Schlichting (TS) waves. Wind-tunnel experiments at Mach numbers of up to M(x)=0.42 and model Reynolds numbers of up to Re(c)=2 × 10(6), as well as in-flight experiments on a wing glove at Mach numbers of M<0.1 and at a Reynolds number of Re(c)=2.4 × 10(6), are presented. Surface hot wires were used to detect the linearly growing TS waves in the transitional boundary layer. Different types of voice-coil- and piezo-driven membrane actuators, as well as active-wall actuators, located between the reference and error sensors, were demonstrated to be effective in introducing counter-waves into the boundary layer to cancel the travelling TS waves. A control algorithm based on the filtered-x least mean square (FxLMS) approach was employed for in-flight and high-speed wind-tunnel experiments. A model-predictive control algorithm was tested in low-speed experiments on an active-wall actuator system. For the in-flight experiments, a reduction of up to 12 dB (75% TS amplitude) was accomplished in the TS frequency range between 200 and 600 Hz. A significant reduction of up to 20 dB (90% TS amplitude) in the flow disturbance amplitude was achieved in high-speed wind-tunnel experiments in the fundamental TS frequency range between 3 and 8 kHz. A downstream shift of the laminar-turbulent transition of up to seven TS wavelengths is presented. The cascaded sensor-actuator arrangement given by Sturzebecher & Nitsche in 2003 for low-speed wind-tunnel experiments was able to shift the transition ?x=240 mm (18% x/c) downstream by a TS amplitude reduction of 96 per cent (30 dB). By using an active-wall actuator, which is much shorter than the cascaded system, a transition delay of seven TS wavelengths (16 dB TS amplitude reduction) was reached. PMID:21382820

Erdmann, Ralf; Pätzold, Andreas; Engert, Marcus; Peltzer, Inken; Nitsche, Wolfgang

2011-04-13

14

An experimental study on laminar-turbulent transition at high free-stream turbulence in boundary layers with pressure gradients  

NASA Astrophysics Data System (ADS)

We report here the results of a study on measurements and prediction of laminar-turbulent transition at high free-stream turbulence in boundary layers of the airfoil-like geometries with presence of the external pressure gradient changeover. The experiments are performed for a number of flow cases with different flow Reynolds number, turbulence intensity and pressure gradient distributions. The results were then compared to numerical calculations for same geometries and flow conditions. The experiments and computations are performed for the flow parameters which are typical for turbomachinery applications and the major idea of the current study is the validation of the turbulence model which can be used for such engineering applications.

Niebles Atencio, Bercelay; Chernoray, Valery; Jahanmiri, Mohsen

2012-04-01

15

Investigation of laminar-turbulent transition in supersonic boundary layers in an axisymmetric aerophysical flight complex and in a model in a wind tunnel in the presence of heat transfer and suction of air  

Microsoft Academic Search

Analysis is made of the problems associated with laminar-turbulent transition in wall boundary layers, as well as of scale\\u000a effects observed in the investigation of laminar-turbulent transition in wind tunnels and laminarization of flow. Flight-performance\\u000a data are given on the Reynolds number and on the gradient criterion of stability at the beginning of transition on the nose\\u000a part of the

A. I. Leontiev; A. M. Pavlyuchenko

2008-01-01

16

A parametric study of LES on laminar-turbulent transitional flows past an airfoil  

NASA Astrophysics Data System (ADS)

Low-Reynolds-number aerodynamic performance of small-sized air vehicles is an area of increasing interest. In this study, low-Reynolds-number flows past an SD7003 airfoil are investigated to understand important viscous features of laminar separation and transitional flow followed by the complicated behavior of the flow reattachment process. In order to satisfy the three-dimensional (3D) requirement of the code, a simple “3D wing” is constructed from a two-dimensional (2D) airfoil. A parametric study of large eddy simulation (LES) on the airfoil flows at Re=60,000 is performed. Effects of grid resolution and sub-grid scale (SGS) models are investigated. Although 3D effects cannot be accurately captured owing to the limitation of the grid resolution in the spanwise direction, the preliminary LES calculations do reveal some important flow characteristics such as leading-edge laminar separation and vortex shedding from the primary laminar separation bubble on the low-Reynolds-number airfoil.

Yuan, W.; Xu, H.; Khalid, M.; Radespiel, R.

2006-01-01

17

Prediction of unsteady, separated boundary layer over a blunt body for laminar, turbulent, and transitional flow  

NASA Astrophysics Data System (ADS)

The focus of this paper is to study the ability of unsteady RANS-based CFD to predict separation over a blunt body for a wide range of Reynolds numbers particularly the ability to capture laminar-to-turbulent transition. A perfect test case to demonstrate this point is the cylinder-in-crossflow for which a comparison between experimental results from the open literature and a series of unsteady simulations is made. Reynolds number based on cylinder diameter is varied from 104 to 107 (subcritical through supercritical flow). Two methods are used to account for the turbulence in the simulations: currently available eddy-viscosity models, including standard and realizable forms of the k- model; and a newly developed eddy-viscosity model capable of resolving boundary layer transition, which is absolutely necessary for the type and range of flow under consideration. The new model does not require user input or empirical fixes to force transition. For the first time in the open literature, three distinct flow regimes and the drag crisis due to the downstream shift of the separation point are predicted using an eddy-viscosity based model with transition effects. Discrepancies between experimental and computational results are discussed, and difficulties for CFD prediction are highlighted.

Holloway, D. Scott; Walters, D. Keith; Leylek, James H.

2004-08-01

18

Characteristic time model validation  

NASA Astrophysics Data System (ADS)

An experimental program for validation of the semi-empirical Characteristic Time Model (CTM) is described. A two-dimensional turbulent shear layer is generated in the experimental test section using a two-stream, vertically downflowing wind tunnel with a flat pre-filming airblast atomizer fitted along its centerline. This facility simulates the shear layer around the recirculation zone found in the primary zone of a gas turbine combustor. Experimental results are used to investigate CTM parameters for turbulent mixing and droplet lifetime and to examine current finite difference modeling techniques. Global mixing times evaluated at the origin of the shear layer and defined in terms of geometric macroscale and a reference velocity are compared with the locally measured values of turbulent mixing time. The results demonstrate that these global times, as defined for the CTM, do in fact accurately represent the events occurring on a local scale, as hypothesized. Modifications to the mixing time parameter to improve existing correlations are proposed. Due to restrictions imposed by the facility and instrumentation, validation of the droplet lifetime parameter was not possible. Measurements were restricted to mean spray diameters. These data and others demonstrate that current correlations for Sauter mean diameter do not adequately account for changes in atomizer geometry or liquid properties.

Tallio, K. V.; Prior, J. C., Jr.; Mellor, A. M.

1988-09-01

19

Numerical study of laminar-turbulent transition in particle-laden channel flow  

NASA Astrophysics Data System (ADS)

We present direct numerical simulations of subcritical transition to turbulence in a particle-laden channel flow, with particles assumed rigid, spherical, and heavier than the fluid. The equations describing the fluid flow are solved with an Eulerian mesh, whereas those describing the particle dynamics are solved by Lagrangian tracking. Two-way coupling between fluid and particles is modeled with Stokes drag. The numerical code is first validated against previous results from linear stability: the nonmodal growth of streamwise vortices resulting in streamwise streaks is still the most efficient mechanism for linear disturbance amplification at subcritical conditions as for the case of a single phase fluid. To analyze the full nonlinear transition, we examine two scenarios well studied in the literature: (1) transition initiated by streamwise independent counter-rotating streamwise vortices and one three-dimensional mode and (2) oblique transition, initiated by the nonlinear interaction of two symmetric oblique waves. The threshold energy for transition is computed, and it is demonstrated that for both scenarios the transition may be facilitated by the presence of particles at low number density. This is due to the fact that particles may introduce in the system detrimental disturbances of length scales not initially present. At higher concentrations, conversely, we note an increase of the disturbance energy needed for transition. The threshold energy for the oblique scenario shows a more significant increase in the presence of particles, by a factor about four. Interestingly, for the streamwise-vortex scenario the time at which transition occurs increases with the particle volume fraction when considering disturbances of equal initial energy. These results are explained by considering the reduced amplification of oblique modes in the two-phase flow. The results from these two classical scenarios indicate that, although linear stability analysis shows hardly any effect on optimal growth, particles do influence secondary instabilities and streak breakdown. These effects can be responsible of the reduced drag observed in turbulent channel flow laden with heavy particles.

Klinkenberg, Joy; Sardina, Gaetano; de Lange, H. C.; Brandt, Luca

2013-04-01

20

Numerical study of laminar-turbulent transition in particle-laden channel flow.  

PubMed

We present direct numerical simulations of subcritical transition to turbulence in a particle-laden channel flow, with particles assumed rigid, spherical, and heavier than the fluid. The equations describing the fluid flow are solved with an Eulerian mesh, whereas those describing the particle dynamics are solved by Lagrangian tracking. Two-way coupling between fluid and particles is modeled with Stokes drag. The numerical code is first validated against previous results from linear stability: the nonmodal growth of streamwise vortices resulting in streamwise streaks is still the most efficient mechanism for linear disturbance amplification at subcritical conditions as for the case of a single phase fluid. To analyze the full nonlinear transition, we examine two scenarios well studied in the literature: (1) transition initiated by streamwise independent counter-rotating streamwise vortices and one three-dimensional mode and (2) oblique transition, initiated by the nonlinear interaction of two symmetric oblique waves. The threshold energy for transition is computed, and it is demonstrated that for both scenarios the transition may be facilitated by the presence of particles at low number density. This is due to the fact that particles may introduce in the system detrimental disturbances of length scales not initially present. At higher concentrations, conversely, we note an increase of the disturbance energy needed for transition. The threshold energy for the oblique scenario shows a more significant increase in the presence of particles, by a factor about four. Interestingly, for the streamwise-vortex scenario the time at which transition occurs increases with the particle volume fraction when considering disturbances of equal initial energy. These results are explained by considering the reduced amplification of oblique modes in the two-phase flow. The results from these two classical scenarios indicate that, although linear stability analysis shows hardly any effect on optimal growth, particles do influence secondary instabilities and streak breakdown. These effects can be responsible of the reduced drag observed in turbulent channel flow laden with heavy particles. PMID:23679517

Klinkenberg, Joy; Sardina, Gaetano; de Lange, H C; Brandt, Luca

2013-04-23

21

Effect of micro-grooved surface on the flow structure in laminar-turbulent transition  

NASA Astrophysics Data System (ADS)

The micro-grooves (or riblets) parallel to the flow streamline have been discovered to reduce surface drag for turbulent boundary layer in the range of 5 < h+ < 25 with a maximum drag reduction of 8%. The drag reduction was suggested to be the confinement of near-wall flow motion. To investigate the drag reduction mechanism, an experimental program was conducted in the laminar, transitional, and turbulent boundary layer on both smooth surface and 3M 0.007-inch V-grooved films. The focus was on the evolution of turbulent spot (T-spot) in the transitional boundary layer and on the bursting of the substructure in the T- spot. Significant efforts have been made to develop a more reliable conditional sampling technique for detecting the T-spots (large structure) and the bursting events (sub- structure in the T-spots). Two new approaches, using modified variable interval time average (m-VITA) method and single threshold value, were introduced to detect T- spot and intermittency. Effects of criterion functions, sampling rate, and threshold values were investigated using both u(t) and uv(t) signals. It was speculated that the micro-grooves; would affect the sub-structures in the T-spots. Two bursting detection techniques, Quadrant 2 (Q2) and VITA, were applied to the transitional boundary layers. The results showed that the bursting frequency increased as intermittency increased downstream in the transitional flow and asymptotically reduced in the turbulent boundary layer. The micro-grooves were found to lengthen the transition region by suppressing the T-spot growth and delaying the merging of T-spot in the near-wall region. The suppression mechanism was supported by the 5 ~ 10% reduction of the bursting frequency in the later transition region, and the mechanism of delaying T-spot merging was manifested by the higher T- spot passing rate in the near-wall region (Y+ < 70) than that away from the wall (Y+ > 100).

Kuan, Chia-Liu

22

Laminar turbulent boundary layers; Proceedings of the Energy Sources Technology Conference, New Orleans, LA, February 12-16, 1984  

Microsoft Academic Search

Among the topics discussed are drag and aeroacoustic noise characteristics due to the coupled roughness and blowing of surfaces, skin friction and heat transfer for combined roughness and mass addition, the effect of drag-reducing additives on the development and separation of a turbulent boundary layer with adverse pressure gradient, numerical investigations of the microbubble drag reduction mechanism, the effects of

E. M. Uram; H. E. Weber

1984-01-01

23

Pulse combustion; The quantification of characteristic times  

Microsoft Academic Search

Measurements of the total ignition delay time in a pulse combustor have been made for several chemical kinetic ignition delay times and several fluid dynamic mixing times. These measured total ignition delay times are compared with calculated values of the characteristic time for mixing and with calculated values for the homogeneous ignition delay time. A chemical kinetic model was used

J. O. Keller; T. T. Bramlette; C. K. Westbrook; J. E. Dec

1990-01-01

24

Predicting the Aerodynamic Characteristics of 2D Airfoil and the Performance of 3D Wind Turbine using a CFD Code  

Microsoft Academic Search

Despite of the laminar-turbulent transition region co-exist with fully turbulence region around the leading edge of an airfoil, still lots of researchers apply to fully turbulence models to predict aerodynamic characteristics. It is well known that fully turbulent model such as standard k-model couldn't predict the complex stall and the separation behavior on an airfoil accurately, it usually leads to

Bum-Suk Kim; Mann-Eung Kim; Young-Ho Lee

2008-01-01

25

Event recognition based on time series characteristics  

Microsoft Academic Search

Event recognition and temporal information analysis are important subtasks in information extraction (IE). In this paper, event recognition based on time series characteristics is proposed. In the pipeline of event recognition, trigger word table is extracted from training corpus and extended based on the field and thesaurus, which is regarded as a priori knowledge. Then event recognition is carried out

Fenghuan Li; Dequan Zheng; Tiejun Zhao

2011-01-01

26

Characteristic Time Scales of Characteristic Magmatic Processes and Systems  

NASA Astrophysics Data System (ADS)

Every specific magmatic process, regardless of spatial scale, has an associated characteristic time scale. Time scales associated with crystals alone are rates of growth, dissolution, settling, aggregation, annealing, and nucleation, among others. At the other extreme are the time scales associated with the dynamics of the entire magmatic system. These can be separated into two groups: those associated with system genetics (e.g., the production and transport of magma, establishment of the magmatic system) and those due to physical characteristics of the established system (e.g., wall rock failure, solidification front propagation and instability, porous flow). The detailed geometry of a specific magmatic system is particularly important to appreciate; although generic systems are useful, care must be taken to make model systems as absolutely realistic as possible. Fuzzy models produce fuzzy science. Knowledge of specific time scales is not necessarily useful or meaningful unless the hierarchical context of the time scales for a realistic magmatic system is appreciated. The age of a specific phenocryst or ensemble of phenocrysts, as determined from isotopic or CSD studies, is not meaningful unless something can be ascertained of the provenance of the crystals. For example, crystal size multiplied by growth rate gives a meaningful crystal age only if it is from a part of the system that has experienced semi-monotonic cooling prior to chilling; crystals entrained from a long-standing cumulate bed that were mechanically sorted in ascending magma may not reveal this history. Ragged old crystals rolling about in the system for untold numbers of flushing times record specious process times, telling more about the noise in the system than the life of typical, first generation crystallization processes. The most helpful process-related time scales are those that are known well and that bound or define the temporal style of the system. Perhaps the most valuable of these times comes from the observed durations and rates of volcanism. There can be little doubt that the temporal styles of volcanism are the same as those of magmatism in general. Volcano repose times, periodicity, eruptive fluxes, acoustic emission structures, lava volumes, longevity, etc. must also be characteristic of pluton-dominated systems. We must therefore give up some classical concepts (e.g., instantaneous injection of crystal-free magma as an initial condition) for any plutonic/chambered system and move towards an integrated concept of magmatism. Among the host of process-related time scales, probably the three most fundamental of any magmatic system are (1) the time scale associated with crystal nucleation (J) and growth (G) (tx}=C{1(G3 J)-{1}/4; Zieg & Marsh, J. Pet. 02') along with the associated scales for mean crystal size (L) and population (N), (2) the time scale associated with conductive cooling controlled by a local length scale (d) (tc}=C{2 d2/K; K is thermal diffusivity), and (3) the time scale associated with intra-crystal diffusion (td}=C{3 L2/D; D is chemical diffusivity). It is the subtle, clever, and insightful application of time scales, dovetailed with realistic system geometry and attention paid to the analogous time scales of volcanism, that promises to reveal the true dynamic integration of magmatic systems.

Marsh, B. D.

2004-05-01

27

Noise characteristics in GPS coordinate time series  

NASA Astrophysics Data System (ADS)

The aim of this paper is to assess the noise characteristics in weekly solutions time series of residual coordinates for 11 GPS stations, using the Allan variance analysis after a trend and periodic components have been removed by wavelet transform. The noise level is determined by the Allan deviation and the noise type by the slope of the Allan variance graph. The data used are the weekly solution of residual coordinate sets of GPS stations, provided by CODE Analysis Centre of the IGS using the BERNES Software and referred to ITRF2000. The selected stations are well distributed and represent good measurements without observation gaps. The application of wavelet transform on these time series permits to better assess their trends and periodic components. The three position components (north, east and vertical) are affected by a combination of white and flicker noise. Both white and flicker noise levels are smallest in the east component and the largest in the vertical component.

Khelifa, Sofiane; Kahlouche, Salem; Ghezali, Boualem

2010-05-01

28

Order parameter in laminar-turbulent patterns  

NASA Astrophysics Data System (ADS)

Over a century, and thousands of articles, after Reynolds' description of the transition to turbulence in pipe flow, a predictive theory of transition is still unavailable. One of the most intriguing phenomena observed near transition ishe coexistence of well-defined and long-lived laminar and turbulent regions, first observed in counter-rotating Taylor-Couette flow in the 1960s [1]. In the 2000s, Prigent & Dauchot [2] showed that these coexisting regions were part of a regular pattern of stripes, whose wavelength and orientation are Reynolds-number-dependent and reproducible. Analogous phenomena have been observed experimentally [2] and numerically [3] in plane Couette flow, in stator-rotor experiments (the flow between a stationary and a rotating disk) [4], in plane Poiseuille simulations [5], and, most recently, in simulations of pipe flow [6].

Tuckerman, L. S.; Barkley, D.; Moxey, D.; Dauchot, O.

29

Predicting river travel time from hydraulic characteristics  

USGS Publications Warehouse

Predicting the effect of a pollutant spill on downstream water quality is primarily dependent on the water velocity, longitudinal mixing, and chemical/physical reactions. Of these, velocity is the most important and difficult to predict. This paper provides guidance on extrapolating travel-time information from one within bank discharge to another. In many cases, a time series of discharge (such as provided by a U.S. Geological Survey stream gauge) will provide an excellent basis for this extrapolation. Otherwise, the accuracy of a travel time extrapolation based on a resistance equation can be greatly improved by assuming the total flow area is composed of two parts, an active and an inactive area. For 60 reaches of 12 rivers with slopes greater than about 0.0002, travel times could be predicted to within about 10% by computing the active flow area using the Manning equation with n = 0.035 and assuming a constant inactive area for each reach. The predicted travel times were not very sensitive to the assumed values of bed slope or channel width.

Jobson, H. E.

2001-01-01

30

Time Dependent Electron Paramagnetic Resonance Characteristics of Detonated Primer Residues.  

National Technical Information Service (NTIS)

The report is a preliminary study examining the EPR characteristics of detonated primer materials in order to determine the feasibility of determining if a primer compound had been discharged recently, estimating the elapsed time since discharge, and esta...

L. A. Franks R. K. Mullen

1971-01-01

31

Connecting Snowmelt Runoff Timing Changes to Watershed Characteristics in California  

NASA Astrophysics Data System (ADS)

Shifts in the timing of snowmelt runoff are an expected consequence of climatic changes and have been observed throughout western North America for the past several decades. While the snowmelt runoff has in general come earlier, the magnitude, and sometimes direction, of streamflow timing trends has varied throughout the region in a manner that is not explained by the differences in location or gauge elevation alone. The gauge-to-gauge differences in the observed streamflow timing trends, which have not been systematically explored, are investigated in this study by linking the hydrologic response of a stream to the physical characteristics of the watershed above the gauge. To this end, the very recent trends in streamflow timing measures (such as the timing of the start of the spring snowmelt pulse, the timing of the center of mass for flow, the annual flow, and the timing of the day when maximum flow occurs) for approximately 60 snowmelt-dominated gauges in California were analyzed in conjunction with a GIS-based data base of the watershed characteristics (such as elevation distribution, slope, aspect, and vegetation) through the 2008 runoff season. The improved knowledge of how a watershed has reacted to recent climatic changes can aid in the development of future adaptive strategies in managing water resources in California.

Stewart, I. T.; Peterson, D. H.

2008-12-01

32

Statistical Characteristics of Atlantic Hurricanes From Time Series Observations  

NASA Astrophysics Data System (ADS)

In the last decade there has been a series of active seasons for hurricanes, including that of 2005. The recent increase in hurricane frequency and intensity may be linked to the trend of increasing global temperatures. Several studies have shown that the rise in global temperatures is correlated with upward trends in sea surface temperature (SST). Such trends have been documented in all ocean regions where hurricanes are formed. The skill in forecasting the seasonal or inter-annual activity of Atlantic hurricanes (AH) with dynamical models is limited, due to a rapid decay of predictability in such models. Nevertheless, time series of data accumulated over more than 100 years yield some insight into the general dynamical features of AH systems. In particular, nonlinear time-series analysis is becoming a reliable tool for the study of complex dynamics from measurements. We present the AH characteristics by analyzing the statistics of long-term time series, illustrating the inter-annual and decadal variability. Hurricane trajectory data, peak wind speed and the "eye" or minimum pressure all display significant variability over the last century. Power spectrum density (PSD) analysis of time series of annual AH numbers shows periods of ~2-3 years and ~ 5 years. These periods are confirmed by PSDs of the annual SST anomaly, between latitudes of 30 S and 30 N, and of the annual CAR Index (the SST anomaly in the Caribbean region). The analysis presented here suggests that part of AH inter-annual variability can be directly linked to SST variations in the same region. The study underlines the potential role of time-series analysis to complement other statistical and dynamic methods used in the description and forecasting of hurricanes.

Andronache, C.; Phillips, V.

2007-05-01

33

Time-Series Analysis of Supergranule Characteristics at Solar Minimum  

NASA Astrophysics Data System (ADS)

Sixty days of Doppler images from the Solar and Heliospheric Observatory (SOHO) / Michelson Doppler Imager (MDI) investigation during the 1996 and 2008 solar minima have been analyzed to show that certain supergranule characteristics (size, size range, and horizontal velocity) exhibit fluctuations of three to five days. Cross-correlating parameters showed a good, positive correlation between supergranulation size and size range, and a moderate, negative correlation between size range and velocity. The size and velocity do exhibit a moderate, negative correlation, but with a small time lag (less than 12 hours). Supergranule sizes during five days of co-temporal data from MDI and the Solar Dynamics Observatory (SDO) / Helioseismic Magnetic Imager (HMI) exhibit similar fluctuations with a high level of correlation between them. This verifies the solar origin of the fluctuations, which cannot be caused by instrumental artifacts according to these observations. Similar fluctuations are also observed in data simulations that model the evolution of the MDI Doppler pattern over a 60-day period. Correlations between the supergranule size and size range time-series derived from the simulated data are similar to those seen in MDI data. A simple toy-model using cumulative, uncorrelated exponential growth and decay patterns at random emergence times produces a time-series similar to the data simulations. The qualitative similarities between the simulated and the observed time-series suggest that the fluctuations arise from stochastic processes occurring within the solar convection zone. This behavior, propagating to surface manifestations of supergranulation, may assist our understanding of magnetic-field-line advection, evolution, and interaction.

Williams, Peter E.; Pesnell, W. Dean

2013-08-01

34

Characteristic times of wind variability in classical T Tauri stars  

NASA Astrophysics Data System (ADS)

Results of observations of short-term wind variability in the classical T Tauri stars RW Aur and DR Tau are presented. Since the H CaII emission is absorbed by the absorption component of the H? line, which arises in the wind at a radial velocity of about -120 km/s, the ratio of equivalent widths of the H and K emission lines of ionized calcium is used as an indicator of the line-of-sight wind density. Observations showed that the wind densities of RW Aur and DR Tau vary with a characteristic time of 4 to 5 days, i.e., with a period that is somewhat shorter than the period of the axial rotation of these stars. These results are interpreted in the framework of the conical wind model, which predicts cyclic repetitions of accretion and ejection events caused by the interaction of the star's magnetosphere with the ionized gas at the inner boundary of the accretion disc.

Babina, E. V.; Artemenko, S. A.; Petrov, P. P.; Grankin, K. N.

2013-06-01

35

A Unified Proof of the Characteristic Model of Linear Time-Invariant Systems  

Microsoft Academic Search

The characteristic modeling problem of linear time-invariant systems is addressed in this paper. It is proved that the characteristic model of the MIMO linear time-invariant systems can be expressed by a time varying difference equation of order 2. The modeling error of characteristic model is discussed. When there is not zero real part pole in the plants, the transient modeling

Bin Meng; Hong-Xin Wu

2007-01-01

36

Supersonic Laminar-Turbulent Gas Flow Past a Circular Cylinder  

Microsoft Academic Search

The flow past a circular cylinder with an isothermal surface at Mach numbers M8=2 and 5 and Reynolds numbers ranging from 104 to 108 is investigated on the basis of the Reynolds equations using a differential two-equation turbulence model. The effect of flow turbulization on the separation point displacement, the separation zone length, the maximum velocity reduction in the separation

V. A. Bashkin; I. V. Egorov; M. V. Egorova; D. V. Ivanov

2000-01-01

37

Banded laminar-turbulent patterns: mean flows, symmetries and statistics  

NASA Astrophysics Data System (ADS)

In large-aspect-ratio plane Couette flow, patterns of oblique bands, alternating between turbulent and laminar flow, are the intermediate regime between uniform turbulence and laminar Couette flow. The mean flows corresponding to these patterns, as well as the Reynolds stress force, are found to be represented almost perfectly by a single trigonometric function along the pattern wavevector, leading to a quantitative description in terms of six ODEs. The Fourier component corresponding to the pattern wavelength provides an order parameter for the transition, which can be described as a bifurcation in its probability distribution function.

Tuckerman, Laurette; Barkley, Dwight

2007-11-01

38

A bypass wake induced laminar\\/turbulent transition  

Microsoft Academic Search

The process of laminar to turbulent transition induced by a von Karman vortex street wake, was studied for the case of a flat plate boundary layer. The boundary layer developed under zero pressure gradient conditions. The vortex street was generated by a cylinder positioned in the free stream. An X-type hot-wire probe located in the boundary layer, measured the streamwise

N. K. Kyriakides; E. G. Kastrinakis; S. G. Nychas; A. Goulas

1999-01-01

39

Light transport contribution to the timing characteristics of scintillation detectors  

Microsoft Academic Search

A Monte Carlo simulation of the light transit time in scintillation detectors is described, with the wavelength dependencies of different interaction processes being taken into account. The simulation results presented give an estimate of the contribution of light transport to the timing resolution of scintillation detectors.

N. Ghal-Eh

2011-01-01

40

Time Domain Measurements to Validate Test Site Characteristics  

NASA Astrophysics Data System (ADS)

This contribution describes time domain measurements for the validation of test sites used for electromagnetic compatibility (EMC) compliance measurements. The normalized site attenuation (NSA) measurement in the frequency domain does not give any information about the kind and position of an error. Contrary to this, the introduced time domain measurement gives the desired error localization possibility.

Battermann, Sven; Garbe, Heyno

41

Statistical Characteristics of Irreversible Predictability Time in Regional Ocean Models.  

National Technical Information Service (NTIS)

Probabilistic aspects of regional ocean model predictability is analyzed using the probability density function (PDF) of the irreversible predictability time (IPT) (called tau-PDF) computed from an unconstrained ensemble of stochastic perturbations in ini...

L. M. Ivanov P. C. Chu

2005-01-01

42

Short-Time Annealing Characteristics of Electrical Conductors  

Microsoft Academic Search

Loss in strength is a function of conductor maximum temperature which, itself, is a function of I2t. Instead of producing currents and times as they may occur in the field, one can, in the laboratory, choose more convenient values giving the same I2t, the same maximum temperature and the same loss in strength. Using this approach, diagrams were developed showing,

L. F. Roehmann; Earl Hazan

1963-01-01

43

Inverting Source Time Functions to determine the fault kinematic characteristics  

NASA Astrophysics Data System (ADS)

In seismology, the analisys of source kinematic parameters (slip-rate and rupture velocity ecc.) is a fundamental way to study the time-history of the rupture process that occurs during a seismic event. To this end various method to reconstruct source kinematics models from the inversion of seismogram have been proposed during the time. In this work we present an alternative methodology to infer source models. We aim, indeed, at obtaining the slip and rupture velocity distribution on the fault plane inverting the apparent Source Time Functions (STFs). This kind of analysis, rather than a classical inversion based on a direct study of seismograms recorded at various stations, may have several advantages. A major advantage is related to the possibility to overcome in the forward modeling any problem related to the computation of the Green's function, as the choice of the correct and reliable propagation model. To retrieve reliable STF, we apply the stabilized deconvolution technique proposed by Vallée [2004]. Based on Empirical Green's Functions (EGF) approach, this technique integrates in the deconvolution process four physical constraints on the STFs, that are causality, positivity, limited duration, and equal area. In any case the EGF approach suffers from certain limitations related to the selection of valuable Empirical Green Function, especially for small events. The approach used to invert the STFs is based on the technique of Emolo and Zollo [2005] to invert strong-motion data. In particular, the slip and the rupture velocity values are specified only at a set of control-points on the fault plane and their distributions on the whole fault are then obtained by a bicubic interpolation. The final slip and rupture velocity values at the fault-grid nodes are then determined by searching for the maximum of a fitness function (based of comparison between real and synthetic STFs) by using the Genetic Algorithm. The number of control-points is progressively increased to move from a high- to low-wavelength description of kinematic parameters on the fault. The optimal model parameter set is chosen according to Akaike Information Criterion [1974]. We present results for some synthetic tests and an application to a seismic events occurred during the 2009 L'Aquila (Central Italy) seismic sequence. In particular, we analyzed a small aftershock occurred on 2009 April 9, at 04:43:09 (UTC) characterized by a seismic moment of 1.07e+15 Nm (Mw 4). We found: a slip distribution, with an average value of 0.8 cm, characterized by a main slip patch located NW of the hypocenter and a rupture velocity distribution (mean value of 2.3 km/s) with a strong acceleration in the same direction.

Toraldo Serra, E. M.; Orefice, A.; Emolo, A.; Zollo, A.

2012-04-01

44

Assessment of nonradiative relaxation time and characteristic diffusion time of neodymium, erbium and cobalt doped low silica calcium aluminosilicate glasses  

Microsoft Academic Search

Nonradiative relaxation time (?) and characteristic diffusion time (??) of Nd, Er and Co doped low silica calcium aluminosilicate (LSCA) glasses were assessed by means of photoacoustic spectroscopy. The results are interpreted in terms of frequency dependence predicted by the theory of Rosencwaig and Gersho. Whereas ? varied between 7.2ms and 36ms, the values of ?? lied between 0.25ms and

L. Mota; J. A. Sampaio; M. G. da Silva; H. Vargas

2011-01-01

45

A comparative study of variability impact on static flip-flop timing characteristics  

Microsoft Academic Search

With the event of nanoscale technologies, new physical phenomena and technological limitations are increasing the process variability and its impact on circuit yield and performances. Like combinatory cells, the sequential cells also suffer of variations, impacting their timing characteristics. Regarding the timing behaviors, setup and hold time violation probabilities are increasing. This article aims at comparing a set of representative

B. Rebaud; M. Belleville; C. Bernard; M. Robert; P. Maurine; N. Azemard

2008-01-01

46

Characteristics of Time-Series Data Collected through Curriculum-Based Reading Measurement.  

ERIC Educational Resources Information Center

|The statistical properties of curriculum-based time-series data were investigated for 67 learning disabled students (grades 1-7). Results suggest that reading growth over time may be described by a negatively accelerated curve and that the statistical characteristics of time-series data are not necessarily independent in naturally occurring data.…

Skiba, Russell J.; And Others

1986-01-01

47

Examining Information Needs for Efficient Motor Carrier Transportation by Investigating Travel Time Characteristics and Logistics.  

National Technical Information Service (NTIS)

This report presents both survey results and field data analysis investigating information needs for motor carrier logistics. Relevant research in the area of estimating travel time characteristics is presented. Survey results of trucking companies and tr...

L. R. Rilett W. L. Eisele

2002-01-01

48

Fractional derivative and time delay damper characteristics in Duffing–van der Pol oscillators  

NASA Astrophysics Data System (ADS)

More general forms of damping in terms of fractional derivative and time delay are investigated.The damping characteristics in Duffing–van der Pol oscillators are taken as examples.The steady state limit cycle bifurcations are solved by the residue harmonic balance.Rapid convergence is obtained by solving linear ODE.Qualitative differences in the damping characteristics for these dampers are found for the first time.

Leung, A. Y. T.; Guo, Zhongjin; Yang, H. X.

2013-10-01

49

Computing the Characteristics of a SubSegment of a Digital Straight Line in Logarithmic Time  

Microsoft Academic Search

\\u000a We address the problem of computing the exact characteristics of any subsegment of a digital straight line with known characteristics.\\u000a We present a new algorithm that solves this problem, whose correctness is proved. Its principle is to climb the Stern-Brocot\\u000a tree of fraction in a bottom-up way. Its worst-time complexity is proportionnal to the difference of depth of the slope

Mouhammad Said; Jacques-Olivier Lachaud

2011-01-01

50

Assessment of nonradiative relaxation time and characteristic diffusion time of neodymium, erbium and cobalt doped low silica calcium aluminosilicate glasses  

NASA Astrophysics Data System (ADS)

Nonradiative relaxation time ( ?) and characteristic diffusion time (??) of Nd, Er and Co doped low silica calcium aluminosilicate (LSCA) glasses were assessed by means of photoacoustic spectroscopy. The results are interpreted in terms of frequency dependence predicted by the theory of Rosencwaig and Gersho. Whereas ? varied between 7.2 ms and 36 ms, the values of ?? lied between 0.25 ms and 0.7 ms. For the neodymium doped LSCA glass, a decrease in ?? was observed as the ion concentration was increased. The results indicates that rare earth ion acts as network modifier, disrupting the glass lattice.

Mota, L.; Sampaio, J. A.; da Silva, M. G.; Vargas, H.

2011-01-01

51

Characteristic time scales in the American dollar-Mexican peso exchange currency market  

NASA Astrophysics Data System (ADS)

Daily fluctuations of the American dollar-Mexican peso exchange currency market are studied using multifractal analysis methods. It is found evidence of multiaffinity of daily fluctuations in the sense that the /qth-order (roughness) Hurst exponent Hq varies with changes in /q. It is also found that there exist several characteristic time scales ranging from week to year. Accordingly, the market exhibits persistence in the sense that instabilities introduced by market events acting around the characteristic time scales (mainly, quarter and year) would propagate through the future market activity. Some implications of our results on the regulation of the dollar-mexpeso market activity are discussed.

Alvarez-Ramirez, Jose

2002-06-01

52

Effect of excessive Internet use on the time–frequency characteristic of EEG  

Microsoft Academic Search

We examined the effect of excessive Internet use on the time–frequency characteristic of the electroencephalogram by wavelet transformed and non-negative matrix factorization (NMF). The event-related potentials (ERP) of normal subjects and excessive Internet users were acquired using the oddball paradigm experiment. We applied the wavelet transformed and event-related spectral perturbation to ERP in order to extract the time–frequency values. The

Hongqiang Yu; Xin Zhao; Ning Li; Mingshi Wang; Peng Zhou

2009-01-01

53

Relationships among time orientation, consumer innovativeness, and innovative behavior: the moderating role of product characteristics  

Microsoft Academic Search

Consumer innovativeness is a critical factor that determines the success of new product introductions. An important but underexplored\\u000a antecedent of consumer innovativeness is time orientation. In this article, we propose a conceptual model of the relationships\\u000a among time orientation, consumer innovativeness, and consumer innovative behavior. We further examine the moderating role\\u000a of several important product characteristics on these relationships. These

Kiran Karande; Altaf Merchant; K. Sivakumar

54

Transient analysis of microwave active circuits based on time-domain characteristic models  

Microsoft Academic Search

A modular method is presented to speed up transient simulation of microwave active circuits which consist of linear components and active devices that are often nonlinear. Firstly, the linear components and active devices are individually characterized by time-domain characteristic models (TDCM's) and lumped equivalent circuits, respectively, to reduce the computer memory. Then, based on deconvolution, the TDCM's of linear components

Qing-Xin Chu; Yuen-Pat Lau; Fung-Yuel Chang

1998-01-01

55

Curriculum Characteristics of Time-Compressed Course in a U.S. Higher Education Institution  

ERIC Educational Resources Information Center

|The study explored characteristics of the curriculum practice of higher education faculty in the context of time-compressed (e.g., 5-6 weeks) courses as compared with regular term (15-16 weeks) courses. The researchers used open-ended questions on a web-based survey at a large doctoral-extensive university in a Midwestern state in the United…

Hyun, Eunsook; Kretovics, Mark; Crowe, Alicia

2006-01-01

56

Response Time of Broiler Chickens to Cimaterol: Meat Tenderness, Muscle Composition, Fiber Size, and Carcass Characteristics  

Microsoft Academic Search

The response time to cimaterol (CIM), a P-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were con- ducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet contain- ing 1 ppm of CIM. Trial 1 consisted of 55,

B. L. Gwartney; S. J. Jones; C. R. Calkins

2010-01-01

57

Multiple Sclerosis That Is Progressive From the Time of Onset: Clinical Characteristics and Progression of Disability  

Microsoft Academic Search

Objective: To use the new consensus definitions of pri- mary progressive multiple sclerosis (PPMS) and progres- sive relapsing multiple sclerosis (PRMS) to report the de- mographic, clinical, and natural history characteristics of multiple sclerosis (MS) that is progressive from the time of onset. Design: Retrospective study by database\\/chart review and telephone interview. Setting: Multiple sclerosis clinic at a university teach-

P. B. Andersson; E. Waubant; L. Gee; D. E. Goodkin

1999-01-01

58

A parametric study of time-domain characteristics of possible UWB antenna architectures  

Microsoft Academic Search

This paper is a step toward defining the characteristics of a suitable antenna to exploit the inherent advantages in pulsed communication systems, specifically that of ultra-wideband. In this respect, several traditional broadband antenna architectures are evaluated with an emphasis given towards a time-domain perspective. In addition, a good UWB antenna should be reasonably efficient over the entire frequency band allocated

Stanislav Licul; Joseph A. N. Noronha; William A. Davis; Dennis G. Sweeney; Christopher R. Anderson; T. M. Bielawa

2003-01-01

59

Evaluation of the Time-Dependent Characteristics of Grouted Sand Using AN Elastic Wave  

Microsoft Academic Search

For a better evaluation of a grouted zone during and after tunnel construction involving weak soil layers, it is necessary to estimate the characteristics of grouted zone effectively. This study suggests a method that can be used for characterizing the time-dependent behavior of pre-reinforced zones around a large section of tunnel in soft ground using elastic waves. Experimental tests were

Joowon Kim; Ki-Il Song; Gye-Chun Cho; Seok-Won Lee

2008-01-01

60

Pulse Combustion: Demonstration of the Characteristic Mixing Time in a Commercial Burner  

Microsoft Academic Search

The response of a prototype Helmholtz-type commercial pulse combustor to changes in two fundamental characteristic times has been investigated both experimentally and numerically. The natural resonant frequency and the fluid dynamic mixing geometry were modified separately. The response of the combustor to these changes was determined by measurements of pressure, frequency, and OH· chemiluminescence. The combustion chamber volume was modified

J. O. Keller; P. K. Barr; T. T. Bramletie; L. J. Evens; R. N. Marchant

1989-01-01

61

Measurement and Analysis of Time Delay Characteristics of Field-Breakdown Triggered Vacuum Switches  

Microsoft Academic Search

This paper focuses on the delay time and its scattering characteristics of field-breakdown TVS. The experimental circuit of TVS is set up and the experiments are carried out to study the effects of several factors including the voltage across the main electrodes, the polarities of the main gap voltage and the trigger pulse voltage on the performance of TVS. Both

Manling Dong; Junjia He; Yuan Pan; Zheng Cheng

2008-01-01

62

Measurement and Analysis of Time Delay Characteristics of Field-Breakdown Triggered Vacuum Switches  

Microsoft Academic Search

This paper focuses on the delay time and its scattering characteristics of field-breakdown triggered vacuum switch (TVS). The experimental circuit of TVS is set up, and the experiments are carried out to study the effects of several factors including the voltage across the main electrodes, the polarities of the main gap voltage, and the trigger pulse voltage on the performance

Manling Dong; Junjia He; Yuan Pan; Zheng Cheng

2009-01-01

63

Portrayals of women in prime-time network television: Some demographic characteristics  

Microsoft Academic Search

This paper examines demographic variables to create a partial picture of current portrayals of women on network television. All prime-time programs for all networks served as the information base. The findings were that few changes had been made in the portrayals of women from the 1970s to the 1980s in terms of observable demographic characteristics.

Donald M. Davis

1990-01-01

64

Jamming transition with fluctuations of characteristic acceleration\\/braking time within Lorentz model  

Microsoft Academic Search

Jamming transition in traffic flow (between free and jammed traffic) for homogeneous car following model has been investigated taking into account fluctuations of characteristic acceleration\\/braking time. These fluctuations are defined by Ornstein-Uhlenbeck process. The behaviour of the most probable deviation of headway from its optimal value has been studied and phase diagram of the system has been calculated for supercritical

Alexei Khomenko; D. O. Kharchenko; Olga Yushchenko

2002-01-01

65

The Relationship Between Gun and Gun Buyer Characteristics and Firearm Time-to-Crime  

Microsoft Academic Search

Gun violence continues to be a major crime control problem in many metropolitan cities in America. To comprehend this problem more completely, this study seeks to develop an understanding of the dynamics of illegal firearm markets in one particular city: Milwaukee, Wisconsin. In particular, the characteristics of guns and gun buyers that are related to fast firearm time-to-crime are identified.

Steven G. Brandl; Meghan S. Stroshine

2011-01-01

66

Influence of harvest time on fuel characteristics of five potential energy crops in northern China  

Microsoft Academic Search

Five potential energy crops in northern China were examined for fuel characteristics over different harvest times to test whether or not a delayed harvest improves fuel quality in a semiarid area in China as is the case in northern Europe and North America. The five crops include indigo bush (Amorpha fruticosa), sand willow (Salix cheilophila), switch grass (Panicum virgatum), reed

Shaojun Xiong; Quan-Guo Zhang; Da-Yong Zhang; Rolf Olsson

2008-01-01

67

Time-variant throughput versus delay characteristics and communication reliability of a wireless local area network  

Microsoft Academic Search

A performance evaluation was conducted to determine the communications throughput, delay, and reliability characteristics of various wireless LAN test configurations located in and between two high-rise office buildings. Internetworking wireless LANs with wired LANs was accomplished to determine its effect on performance. The locations of the workstations and file servers, the time of their operation, and the type of architecture

Larry Wasson; Richard Lee; Allen Rossmiller

1992-01-01

68

The Camberwell Cohort 25 Years On: Characteristics and Changes in Skills over Time  

ERIC Educational Resources Information Center

|Background: This study presents data on the characteristics of the Camberwell Cohort, 25 years after they were first assessed in the 1970s [Wing & Gould (1979) "Journal of Autism and Childhood Schizophrenia" vol. 9, pp. 11-29]. It also presents data on changes over time which adds to that presented in Beadle-Brown et al. ["Journal of Intellectual…

Beadle-Brown, Julie; Murphy, Glynis; Wing, Lorna

2006-01-01

69

The family as portrayed on prime-time television, 1947–1990: Structure and characteristics  

Microsoft Academic Search

“Successful family series” across four decades of American prime-time television were examined. Family portrayals were defined as either conventional or nonconventional. Conventional families were categorized as “couples without children” and “couples with children.” Nonconventional families were categorized as “single parent” or “contrived.” Additional family characteristics were also recorded including sex of single parent, reason for singleness, social class status, females

Marvin L. Moore

1992-01-01

70

Event and time-scale characteristics of heart-rate dynamics  

NASA Astrophysics Data System (ADS)

The cardiac system shows various scale dynamic activities from secondly to yearly. Therefore multiple time-scale characteristics of heart dynamics have received much attention for understanding and distinguishing healthy and pathological cardiac systems. In this paper we expand the multiple time-scale analysis into event and time scales to investigate scale characteristics in healthy and pathologic cardiac systems. To do this, we define a measure based on symbolic dynamics, which calculates complexity at each time and event scale, called the unit time block entropy (UTBE). This measure allows a reliable comparison of experimental data through matching the number of words and the total measurement time at the same time for all RR interval sequences which are composed of the time durations between consecutive R waves of electrocardiograms. We apply the UTBE to the healthy heart-rate (HR) group and pathological HR groups and find that the RR interval acceleration is more effective than the RR interval in distinguishing each group. And we also find that the normal and pathological HR groups are clearly distinguished in some specific event and time-scale regions.

Lee, Uncheol; Kim, Seunghwan; Yi, S. H.

2005-06-01

71

The relationship among college science student achievement, engaged time, and personal characteristics  

NASA Astrophysics Data System (ADS)

The relationships among college student science achievement, engaged time (observed and perceived), and personal characteristics of academic aptitude, reasoning ability, attitude toward science, and locus of control were investigated. Measures of personal characteristics were obtained from the subjects (N= 76) of a private, liberal arts junior college before observations began in the lecture classes for the quarter. Instruments used to measure personal characteristics were Scholastic Aptitude Test, Test of Logical Thinking, Test of Scientific Attitude, and Leven-son's Multidimensional View of Locus of Control. Based on a random selection procedure, student engaged time was observed at least ten times for 11 lectures. Achievement tests were constructed and validated for the biology classes. Data were analyzed by multiple regression procedures. The average achievement scores were positively related to academic aptitude and reasoning ability. Positive relationships were found between observed engaged time and academic aptitude and a negative relationship was found between observed engaged time and reasoning ability. Also a positive relationship was found between perceived engaged time and achievement. Pearson product-moment correlations between achievement and observed engaged time were significant as were the correlations between perceived engaged time and achievement. Measure of engaged time (observed and perceived) were also related to each other. The study's data indicate that students who were observed to be engaged were low in reasoning ability or high in academic aptitude. Those who perceived themselves as being engaged achieved more. College instructors who have knowledge of student academic aptitude and reasoning ability may use this knowledge to improve achievement.Engaged time measures were significantly related to achievement, which indicates an instructor should endeavor to keep the students as engaged as possible to enhance achievement. Students who are engaged or pay attention or perceived they are engaged or paying attention during lecture classes achieve more than students who are observed as nonengaged or perceive themselves as nonengaged.

Johnson, T. Franklin; Butts, David P.

72

The Dependence of Characteristic Times of Gradual SEP Events on Their Associated CME Properties  

NASA Astrophysics Data System (ADS)

It is generally believed that coronal mass ejections CMEs are the drivers of shocks that accelerate gradual solar energetic particles SEPs One might expect that the characteristics of the SEP intensity time profiles observed at 1 AU are determined by properties of the associated CMEs such as the radial speed and the angular width Recently Kahler statistically investigated the characteristic times of gradual SEP events observed from 1998-2002 and their associated coronal mass ejection properties Astrophys J 628 1014--1022 2005 Three characteristic times of gradual SEP events are determined as functions of solar source longitude 1 T 0 the time from associated CME launch to SEP onset at 1 AU 2 T R the rise time from SEP onset to the time when the SEP intensity is a factor of 2 below peak intensity and 3 T D the duration over which the SEP intensity is within a factor of 2 of the peak intensity However in his study the CME speeds and angular widths are directly taken from the LASCO CME catalog In this study we analyze the radial speeds and the angular widths of CMEs by an ice-cream cone model and re-investigate their correlationships with the characteristic times of the corresponding SEP events We find T R and T D are significantly correlated with radial speed for SEP events in the best-connected longitude range and there is no correlation between T 0 and CME radial speed and angular width which is consistent with Kahler s results On the other hand it s found that T R and T D are also have

Pan, Z. H.; Wang, C. B.; Xue, X. H.; Wang, Y. M.

73

The influence of travel time on breast cancer characteristics, receipt of primary therapy, and surveillance mammography.  

PubMed

Travel time has been shown to influence some aspects of cancer characteristics at diagnosis and care for women with breast cancer, but important gaps remain in our understanding of its impact. We examined the influence of travel time to the nearest radiology facility on breast cancer characteristics, treatment, and surveillance for women with early-stage invasive breast cancer. We included 1,012 women with invasive breast cancer (stages I and II) who had access to care within an integrated health care delivery system in western Washington State. The travel times to the nearest radiology facility were calculated for all the U.S. Census blocks within the study area and assigned to women based on residence at diagnosis. We collected cancer characteristics, primary and adjuvant therapies, and surveillance mammography for at least 2.5 years post diagnosis and used multivariable analyses to test the associations of travel time. The majority of women (68.6%) lived within 20 min of the nearest radiology facility, had stage I disease (72.7%), received breast conserving therapy (68.7%), and had annual surveillance mammography the first 2 years after treatment (73.7%). The travel time was not significantly associated with the stage or surveillance mammography after adjusting for covariates. Primary therapy was significantly related to travel time, with greater travel time (>30 min vs. ? 10 min) associated with a higher likelihood of mastectomy compared to breast conserving surgery (RR = 1.53; 95% CI, 1.16-2.01). The travel time was not associated with the stage at diagnosis or surveillance mammography receipt. The travel time does seem to influence the type of primary therapy among women with breast cancer, suggesting that women may prefer low frequency services, such as mastectomy, if geographic access to a radiology facility is limited. PMID:21553117

Onega, Tracy; Cook, Andrea; Kirlin, Beth; Shi, Xun; Alford-Teaster, Jennifer; Tuzzio, Leah; Buist, Diana S M

2011-05-07

74

Characteristic times in the nanometer-picosecond translational collective dynamics of molecular liquids.  

PubMed

Molecular-dynamics calculations of the translational dynamic structure factor in liquid CO2 and CD4 are analyzed by means of the generalized Langevin equation for the intermediate scattering function in the second-order memory function approximation. We give a rigorous general relation among the decay times of the memory and the lifetimes of the modes of the density-density correlation function. The comparison of the various characteristic times among them and with the collision time, carried out as a function of the wave vector, reveals strong relationships between the memory relaxation and the density-density correlation modes, some of which have purely "collisional" and other "collective" character. We show that essential information about the life time of structural properties in a molecular liquid at nanometer dimensions can be obtained if the time behavior of the correlation function is considered in addition to that of the memory function. PMID:19905262

Bafile, Ubaldo; Guarini, Eleonora; Sampoli, Marco; Barocchi, Fabrizio

2009-10-12

75

Characteristic times in the nanometer-picosecond translational collective dynamics of molecular liquids  

NASA Astrophysics Data System (ADS)

Molecular-dynamics calculations of the translational dynamic structure factor in liquid CO2 and CD4 are analyzed by means of the generalized Langevin equation for the intermediate scattering function in the second-order memory function approximation. We give a rigorous general relation among the decay times of the memory and the lifetimes of the modes of the density-density correlation function. The comparison of the various characteristic times among them and with the collision time, carried out as a function of the wave vector, reveals strong relationships between the memory relaxation and the density-density correlation modes, some of which have purely “collisional” and other “collective” character. We show that essential information about the life time of structural properties in a molecular liquid at nanometer dimensions can be obtained if the time behavior of the correlation function is considered in addition to that of the memory function.

Bafile, Ubaldo; Guarini, Eleonora; Sampoli, Marco; Barocchi, Fabrizio

2009-10-01

76

Shape measurement tools in footwear analysis: A statistical investigation of accidental characteristics over time.  

PubMed

Presence of accidental characteristics on footwear strengthens the linkage of a given piece of footwear to a footwear impression left at a crime-scene. Thus an understanding of rate of appearance and disappearance of these characteristics is of importance. Artificial cut-marks, 1-3mm in depth, were cut into outsoles of 11 pairs of athletic shoes. Loss of these cut-marks and acquisition of new accidental characteristics/wear patterns were monitored over a seven-week time-span. Feature-vector methods were used to acquire multivariate data on wear/acquisition rates. A repeatability study indicated the feature vector method could detect small differences among shoes relative to measurement uncertainty. The shoes displayed a strong retention of artificial cut-marks over the study interval. Net rate of wear was 0.1% of the textured area of the shoe per week, predominantly in the heel and ball area. Results indicate accidental characteristics can reasonably be expected to persist over time. PMID:24053869

Sheets, H David; Gross, Susan; Langenburg, Glenn; Bush, Peter J; Bush, Mary A

2013-08-07

77

Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization  

SciTech Connect

The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracture toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.

Advani, S.H.; Lee, T.S. (Lehigh Univ., Bethlehem, PA (United States)); Moon, H. (Ohio State Univ., Columbus, OH (United States))

1992-10-01

78

Application of characteristic time concepts for hydraulic fracture configuration design, control, and optimization. Final report  

SciTech Connect

The analysis of pertinent energy components or affiliated characteristic times for hydraulic stimulation processes serves as an effective tool for fracture configuration designs optimization, and control. This evaluation, in conjunction with parametric sensitivity studies, provides a rational base for quantifying dominant process mechanisms and the roles of specified reservoir properties relative to controllable hydraulic fracture variables for a wide spectrum of treatment scenarios. Results are detailed for the following multi-task effort: (a) Application of characteristic time concept and parametric sensitivity studies for specialized fracture geometries (rectangular, penny-shaped, elliptical) and three-layered elliptic crack models (in situ stress, elastic moduli, and fracture toughness contrasts). (b) Incorporation of leak-off effects for models investigated in (a). (c) Simulation of generalized hydraulic fracture models and investigation of the role of controllable vaxiables and uncontrollable system properties. (d) Development of guidelines for hydraulic fracture design and optimization.

Advani, S.H.; Lee, T.S. [Lehigh Univ., Bethlehem, PA (United States); Moon, H. [Ohio State Univ., Columbus, OH (United States)

1992-10-01

79

Walnut, microbial transglutaminase and chilling storage time effects on salt-free beef batter characteristics  

Microsoft Academic Search

Response surface methodology (RSM) was used to assess the effect of walnut content (W), microbial transglutaminase\\/sodium caseinate (MTG\\/C) content and storage time (ST) at 3 °C on water- and fat-binding properties,\\u000a texture profile analysis and dynamic rheological characteristics of salt-free beef batters. Walnut addition favoured the binding\\u000a properties and elastic modulus (G?) of raw meat batters (20 °C); however, increasing amounts of

Susana Cofrades; Josune Ayo; Asunción Serrano; José Carballo; Francisco Jiménez-Colmenero

2006-01-01

80

Force-time characteristics and fiber composition in human leg extensor muscles  

Microsoft Academic Search

Summary  Recording of the force-time (f-t) characteristics of muscular contraction expresses the rate at which tension is developed. To further understand the problems involved in force production during voluntary contraction, the f-t curve was registered during maximal voluntary isometric extension of both legs performed in the sitting position with the knee angle at 107 degrees. 38 athletes representing various sport events,

J. T. Viitasalo; P. V. Komi

1978-01-01

81

Electron irradiation for adjusting the reverse recovery time and forward voltage drop characteristics of fast diodes  

Microsoft Academic Search

The electron linear accelerator ALIN-10 has been used to irradiate at room temperature and high temperature silicon diodes type BA159, BAX157 and 6DRR1 (manufacturer – Baneasa S.A.-factory 2300, Romania). The influence of 10 MeV electron irradiation upon the main electrical characteristics (reverse recovery time, forward voltage, reverse current) has been examined for different absorbed doses (10–50 kGy) and different irradiation

Elena Iliescu; Anastase Niculescu; Viorel Banu; Anca Nichita; Nicoleta Sturzu

1998-01-01

82

Associations of Various Family Characteristics and Time Use With Children's Body Mass Index  

Microsoft Academic Search

This study used multiple regression models to estimate associations of various family characteristics and time use with the body mass index (BMI) z-scores of 734 boys and 725 girls aged 5–18y from the Panel Study of Income Dynamics Child Development Supplement 2003. The strongest relationship in the data was between the BMI of the head of household and a child's

Richard A. Forshee; Patricia A. Anderson; Maureen L. Storey

2009-01-01

83

Characteristics of a 1200 V PT IGBT with trench gate and local life time control  

Microsoft Academic Search

A new 1200 V IGBT with a VCE(sat) of 1.9 V at 125°C and 140 A\\/cm2 has been developed using a trench gate PT (punch-through) structure and local life time control. Compared to state-of-the-art third generation planar devices, this device represents a 30% improvement of on-state losses at almost twice the current density. This paper describes the structure and characteristics

Eric R. Motto; John F. Donlon; H. Takahashi; M. Tabata; H. Iwamoto

1998-01-01

84

A characteristic time scale of tick quotes on foreign currency markets  

Microsoft Academic Search

This study investigates that a characteristic time scale on an exchange rate market (USD\\/JPY) is examined for the period of\\u000a 1998 to 2000. Calculating power spectrum densities for the number of tick quotes per minute and averaging them over the year\\u000a yield that the mean power spectrum density has a peak at high frequencies. Consequently it means that there exist

Aki-Hiro Sato

2005-01-01

85

Influence of harvest time on fuel characteristics of five potential energy crops in northern China.  

PubMed

Five potential energy crops in northern China were examined for fuel characteristics over different harvest times to test whether or not a delayed harvest improves fuel quality in a semiarid area in China as is the case in northern Europe and North America. The five crops include indigo bush (Amorpha fruticosa), sand willow (Salix cheilophila), switch grass (Panicum virgatum), reed canary grass (Phalaris arundinacea), and sainfoin (Onobrychis viciifolia). These crops are considered as fuels for thermal conversion. From September 2002 to April 2003, biomass was sampled monthly, and the effects of harvest time on the fuel characteristics of the five crops were studied. With respect to ash and some undesired element contents in biomass, a delayed harvest in spring resulted in a better fuel quality than a traditional harvest in autumn. Of the five species, indigo bush and sand willow had the lowest ash contents when harvested in spring. Switch grass is a promising herbaceous energy crop in semiarid areas in terms of its yield, fuel characteristics, and low water use. Chlorine had the most significant correlation with harvest time and ash content in the biomass. In a comparison with the biofuel crops in Europe and North America, a much higher proportion of chlorine was found in all examined plants. The results from this study indicate that an energy crop with delayed harvest may extend fuel resources and conserve soil in semiarid regions in northern China, practices that will help maintain and improve economical and ecological sustainability. PMID:17382539

Xiong, Shaojun; Zhang, Quan-Guo; Zhang, Da-Yong; Olsson, Rolf

2007-03-26

86

Effects of extended wait time on discourse characteristics and achievement in middle school grades  

NASA Astrophysics Data System (ADS)

The study was conducted in 20 intact classes in grades 6 and 7 from suburban schools in Perth, Australia. The study investigated changes in discourse attributable to the use of an extended teacher wait time in a sequence of seven lessons related to probabilistic reasoning. A wait time feedback group of 10 classes obtained a significantly higher summative achievement mean than a control group that utilized a normal wait time. The results indicated that teacher wait time increased significantly over a seven lesson sequence from an average of 1.9 seconds to an average of 4.4 seconds. Discourse patterns in whole class settings also changed throughout the study. Although the total number of utterances decreased, the average length of pupil utterances increased. Changes were also observed in the teacher discourse. The most notable of these related to the type of teacher talk that followed a pupil response to a question. Teachers tended to probe to obtain further pupil input rather than mimicking pupil responses. The average length of student discourse and the proportion of student reacting were significantly related to summative achievement. The results of the study have indicated that the use of an extended teacher wait time in whole class settings can improve teacher and pupil discourse characteristics. However, the changes that occur are different to those that occur when an extended wait time is used in work groups. Teachers may need to be sensitized to the differing effects of longer wait time in whole class, work group, and individualized settings.

Tobin, Kenneth

87

Time-Domain Analysis of Tunability and Modulation Characteristics in Coupled-Ring Reflector Laser Diode  

NASA Astrophysics Data System (ADS)

The characteristics of a widely tunable coupled-ring reflector laser diode are studied using a time-domain modeling approach. The coupled-ring reflector is a planar waveguide reflector which does not require distributed Bragg gratings. Instead, the coupled-ring reflector consists of a bus waveguide and two coupled ring resonators coupled to the bus. It is shown that the tuning range can be a few tens of nanometers with a side mode suppression ratio exceeding 35 dB through the adjustment of currents into the phase control sections in the rings. The coupled-ring reflector laser diode has a long effective cavity compared with conventional laser diodes. Accordingly, a broad additional resonance peak in the amplitude modulation characteristics is observed between 20 to 30 GHz, implying the extension of amplitude modulation bandwidth.

Kim, Suhyun; Yoon, Pilhwan; Chung, Youngchul

2008-05-01

88

[Atmospheric pollution characteristic during fireworks burning time in spring festival in Quanzhou suburb].  

PubMed

Atmospheric pollution characteristics during fireworks burning time in 2009 Spring Festival in Quangzhou suburb were studied. Particulate aerosol has been monitored and collected using real-time monitor and middle-volume sampler during fireworks burning time. The objectives of this study were to identify the contents and distributing characteristics of particles, polycyclic aromatic hydrocarbon (PAHs) and water-soluble ions and to discuss sources of these pollutants. The results showed that PM2.5 and PM10 were increased significantly during fireworks burning time. The highest concentration of particles presented time of 00:57-01:27 on New Year's Eve, which the average concentration of PM2.5 and PM10 were reached 1102.43 microm(-3) and 1610.22 microg x m(-3) in 30 min. The concentration of particle- and gas-PAHs were 54.18 ng x m(-1) and 47.10 ng x m(-3), respectively, during fireworks burning time in New Year's Eve, which were higher than that in the normal day. It can be judged by the diagnostic ratios that the primary source of PAHs in Quanzhou suburb were the combustion of coal, biomass and the exhaust emission from diesel vehicles in this region. Results of water-soluble ions indicated that fireworks burning were the main reason to lead to higher concentration of these ions during Spring Festival. Moreover, pollution gases of NOx and SO2 that were origined from fireworks burning, coal combustion and exhaust emission from motor vehicle were supplied precursors to form secondary pollutants, such as NO3- and SO4(2-). PMID:21780572

Zhao, Jin-ping; Xu, Ya; Zhang, Fu-wang; Chen, Jin-sheng

2011-05-01

89

CORRELATES OF ADOLESCENT SLEEP TIME AND VARIABILITY IN SLEEP TIME: THE ROLE OF INDIVIDUAL AND HEALTH RELATED CHARACTERISTICS  

PubMed Central

Objectives Adolescents are predisposed to short sleep duration and irregular sleep patterns due to certain host characteristics (e.g., age, pubertal status, gender, ethnicity, socioeconomic class, and neighborhood distress) and health-related variables (e.g., ADHD, asthma, birth weight, and BMI). The aim of the current study was to investigate the relationship between such variables and actigraphic measures of sleep duration and variability. Method Cross-sectional study of 247 adolescents (48.5% female, 54.3% ethnic minority, mean age of 13.7 years) involved in a larger community-based cohort study. Results Significant univariate predictors of sleep duration included gender, minority ethnicity, neighborhood distress, parent income, and BMI. In multivariate models, gender, minority status, and BMI were significantly associated with sleep duration (all p<.05), with girls, non-minority adolescents, and those of a lower BMI obtaining more sleep. Univariate models demonstrated that age, minority ethnicity, neighborhood distress, parent education, parent income, pubertal status, and BMI were significantly related to variability in total sleep time. In the multivariate model, age, minority status, and BMI were significantly related to variability in total sleep time (all p<.05), with younger adolescents, non-minority adolescents, and those of a lower BMI obtaining more regular sleep. Conclusions These data show differences in sleep patterns in population sub-groups of adolescents which may be important in understanding pediatric health risk profiles. Subgroups that may particularly benefit from interventions aimed at improving sleep patterns include boys, overweight, and minority adolescents.

Moore, Melisa; Kirchner, H. Lester; Drotar, Dennis; Johnson, Nathan; Rosen, Carol; Redline, Susan

2011-01-01

90

Characteristic Evaluation of Synchronous Motors Using an Universal Drive System with a Real-Time Interface  

NASA Astrophysics Data System (ADS)

In this paper, a new universal drive system of synchronous motors used Real-Time Interface (RTI) performs characteristic evaluation of Synchronous Reluctance (SynR) motors and Surface Permanent Magnet (SPM) synchronous motors. The RTI connects directly a simulation model with experimental equipment, and makes it possible to use the simulation model for an experiment. The RTI is very effective in the early detection of an actual problem and examination of solution technique. Moreover, it concentrates on examination of control algorithm, and efficient research and development are enabled. A measuring system of synchronous motors is built by the universal drive system. The examination of various synchronous motors is possible for the measurement system using the same control algorithm. Characteristic evaluation of a SynR motor and a SPM synchronous motor that are the same gap length and stator was performed using the measuring system. The measurement result shows experimentally that motor loss of the SynR motor is smaller rather than the SPM synchronous motor, at the time of high speed and low load operation. For example, the SynR motor is suitable to hybrid cars with the comparatively long time of low load and high-speed operation.

Amano, Yoko; Ogasawara, Satoshi

91

Characteristics of beam collision timing and position at the KEK B-factory  

NASA Astrophysics Data System (ADS)

Using the Belle detector we study the characteristics of beam collisions at the KEKB 3.5 GeV e+ and 8 GeV e- asymmetric energy collider. We investigate the collision timing tIP and its z-coordinate along the beam axis zIP as a function of the position of the colliding bunch in a beam train. The various tIP and zIP behaviors observed by Belle are attributed to beam loading effects in the radio frequency cavities that accelerate the beams with a beam abort gap. We also discuss the prospects for the Super-KEKB collider.

Kichimi, H.

2010-11-01

92

Time-motion analysis, heart rate, and physiological characteristics of international canoe polo athletes.  

PubMed

Forbes, SC, Kennedy, MD, and Bell, GJ. Time-motion analysis, heart rate, and physiological characteristics of international canoe polo athletes. J Strength Cond Res 27(10): 2816-2822, 2013-To evaluate the time international canoe polo players spend performing various game activities, measure heart rate (HR) responses during games, and describe the physiological profile of elite players. Eight national canoe polo players were videotaped and wore HR monitors during 3 games at a World Championship and underwent fitness testing. The mean age, height, and weight were 25 ± 1 years, 1.82 ± 0.04 m, and 81.9 ± 10.9 kg, respectively. Time-motion analysis of 3 games indicated that the players spent 29 ± 3% of the game slow and moderate forward paddling, 28 ± 5% contesting, 27 ± 5% resting and gliding, 7 ± 1% turning, 5 ± 1% backward paddling, 2 ± 1% sprinting, and 2 ± 1% dribbling. Sixty-nine (±20)% of the game time was played at an HR intensity above the HR that corresponded to the ventilatory threshold (VT) that was determined during the peak V[Combining Dot Above]O2 test. Peak oxygen uptake and VT were 3.3 ± 0.3 and 2.2 ± 0.3 L·min, respectively, on a modified Monark arm crank ergometer. Arm crank peak 5-second anaerobic power was 379 W. The majority of the time spent during international canoe polo games involved slow-to-moderate forward paddling, contesting for the ball, and resting and gliding. Canoe polo games are played at a high intensity indicated by the HR responses, and the physiological characteristics suggest that these athletes had high levels of upper body aerobic and anaerobic fitness levels. PMID:23287835

Forbes, Scott C; Kennedy, Michael D; Bell, Gordon J

2013-10-01

93

Transient Stability Analysis of Induction Generator Using Time Domain Torque Characteristic  

NASA Astrophysics Data System (ADS)

Transient stability assessment of the wind power generator is one of main issue in power system security and operation. The transient stability of the wind power generator is determine by its corresponding Critical Clearing Time(CCT). In this paper, we present the formulae to the transient behavior analysis and the transient stability analysis technique of induction generator used in wind power generating system at the three-phase fault condition. In the proposed method, the transient stability of the induction generator is analyzed using well known torque-slip and generator speed-time characteristics. The validity of the developed technique is confirmed with the results obtained from trials and error method using MATLAB/SIMULINK.

Senjyu, Tomonobu; Sueyoshi, Norihide; Uezato, Katsumi; Fujita, Hideki; Funabashi, Toshihisa

94

Numerical solution of the time dependent neutron transport equation by the method of the characteristics  

NASA Astrophysics Data System (ADS)

This study presents three numerical algorithms to solve the time dependent neutron transport equation by the method of the characteristics. The algorithms have been developed taking into account delayed neutrons and they have been implemented into the novel MCART code, which solves the neutron transport equation for two-dimensional geometry and an arbitrary number of energy groups. The MCART code uses regular mesh for the representation of the spatial domain, it models up-scattering, and takes advantage of OPENMP and OPENGL algorithms for parallel computing and plotting, respectively. The code has been benchmarked with the multiplication factor results of a Boiling Water Reactor, with the analytical results for a prompt jump transient in an infinite medium, and with PARTISN and TDTORT results for cross section and source transients. The numerical simulations have shown that only two numerical algorithms are stable for small time steps.

Talamo, Alberto

2013-05-01

95

A Prospective Cohort Study of Menstrual Characteristics and Time to Pregnancy  

PubMed Central

The authors examined the association between menstrual characteristics and time to pregnancy among 2,653 Danish women enrolled in a prospective cohort study (2007–2009). Menstrual characteristics were reported at baseline. Outcome data were updated bimonthly until pregnancy, fertility treatment, loss to follow-up, or end of observation (12 cycles). Adjusted fecundability ratios and 95% confidence intervals were estimated by using discrete-time Cox regression models. Relative to average cycle lengths (27–29 days), fecundability ratios for cycle lengths <25, 25–26, 30–31, 32–33, and ?34 days were 0.64 (95% confidence interval (CI): 0.49, 0.84), 0.94 (95% CI: 0.77, 1.13), 1.10 (95% CI: 0.97, 1.25), 1.35 (95% CI: 1.06, 1.73), and 1.17 (95% CI: 0.91, 1.49), respectively. Compared with cycles that regularized within 2 years after menarche, fecundability ratios for cycles that regularized 2–3 and ?4 years after menarche were 0.90 (95% CI: 0.80, 1.02) and 0.89 (95% CI: 0.77, 1.03), respectively. Fecundability ratios were 0.87 (95% CI: 0.72, 1.05) comparing <3 with 3–4 days of menstrual bleeding and 0.70 (95% CI: 0.43, 1.13) comparing very heavy with moderate flow. In the present study, shorter cycle length was associated with delayed time to pregnancy. Age at menarche, time to menstrual regularization, and duration or intensity of menstrual flow were not appreciably associated with fecundability.

Wise, Lauren A.; Mikkelsen, Ellen M.; Rothman, Kenneth J.; Riis, Anders H.; S?rensen, Henrik Toft; Huybrechts, Krista F.; Hatch, Elizabeth E.

2011-01-01

96

Norm Stability in Jirisan National Park: Effects of Time, Existing Conditions, and Background Characteristics  

NASA Astrophysics Data System (ADS)

Norm stability is an important issue to consider in using the normative approach as a component of resource management decision making. This study examines three major questions related to norm stability: (1) Do norms change over time? (2) Do existing conditions affect norms? (3) Do background characteristics and visitation patterns affect norms? Data used in this study were collected at a campground in the Jirisan National Park (JNP) of Korea in 1993, 1994, and 2003. A total of 396 subjects were used for the study (120 for 1993, 106 for 1994, and 170 for 2003). Changes in the standards for “quiet time” and “seeing others littering” were statistically significant, but there was no change in the standard for “number of other tents.” There was little change in norm agreement or norm prevalence. Existing conditions were strongly correlated with standards for number of other tents but results were mixed for the other two indicators. Users’ demographic characteristics and visitation patterns were not generally related to norms. Findings of the study are discussed.

Kim, Sang-Oh; Shelby, Bo

2008-04-01

97

Sperm Metabolism and Biochemical Characteristics in First-Time and Second-Time Spawners of Farmed Atlantic Cod  

Microsoft Academic Search

We compared sperm biochemical characteristics of first-generation (F1) hatchery-reared broodstock of Atlantic cod Gadus morhua during the first and second spawnings to investigate potential improvements in sperm quality between the two spawning events. To gain further perspective on the sperm characteristics investigated, the values for farmed Atlantic cod were also compared with sperm characteristics of wild, experienced spawners that had

Dounia Hamoutene; Lynn Lush; Kimberly Burt; Stephanie Samuelson; Dwight Drover; Andy Walsh

2011-01-01

98

Discharge time dependence of a solution plasma process for colloidal copper nanoparticle synthesis and particle characteristics  

NASA Astrophysics Data System (ADS)

In this study, we investigate a new synthetic route, termed the solution plasma process, for the synthesis of colloidal copper nanoparticles (CuNPs) in the presence of an amide and acid capping agent. Gelatin and ascorbic acid were selected as the capping agents to protect the particles against coalescence and oxidation side reaction. Using a high voltage power supply, CuNPs were rapidly formed by 1 min after the discharge. The size and shape of the CuNPs were dependent on the discharge time and were clearly influenced by the effect of the capping agents under two characteristics of the discharge medium (pH and temperature). With a long discharge time, the CuNP size tended to decrease with the formation of anisotropic particle morphologies: spherical, cubic, hexagonal, triangular and rod-like shapes. The decrease in CuNP size as a function of discharge time could be explained by the dissolution of CuNPs in a lower pH solution. After 5 min discharge the capping agent evidently allowed the protection of the synthesized CuNPs against oxidation with the presence of anisotropic CuNP shapes. It is demonstrated that the CuNP shape could be tuned from spherical to anisotropic shapes without the undesirable oxidation by adjusting the discharge time of the solution plasma. These advantages are valuable for material engineering to design the properties of Cu-based nanoparticles for the desired applications.

Pootawang, Panuphong; Saito, Nagahiro; Lee, Sang Yul

2013-02-01

99

Stratigraphy and Characteristic Time Scales of Northern Polar and Circumpolar Deposits on Mars  

NASA Astrophysics Data System (ADS)

The north polar region is dominated by the polar cap cut by troughs and Chasma Boreale, surrounded by the north polar erg and overlying the Vastitas Borealis Formation. A thin layer of mantle with characteristic "basketball" texture typical for high latitudes covers the surface of Vastitas Borealis Formation. Study of the high-resolution MGS MOC images showed that the dunes migrate over this mantle. The stratigraphic relationships of this mantle and icy deposits, as well as Chasma Boreale-related deposits are more complex. Chasma Boreale has been interpreted to be initiated as an outflow event (Fishbaugh and Head, JGR, JE001351, 2002). We estimate that the time scale of the meltwater accumulation at the base of the polar cap and the time scale of establishing the thermal equilibrium in the cap are on the order of 0.5 Myr or greater. We compare this time scale with the characteristic astronomically predicted time scales: the time scale of obliquity oscillations (0.05 Myr), the period of obliquity oscillations about 25 deg (3.5 Myr), and the time scale of chaotic obliquity variations (5 Myr). During the period 3.5 - 5 Myr ago the obliquity oscillated around 35 deg, which led to noticeably higher polar cap temperatures and a shallower depth of the melting isotherm than during the present epoch. Predictions of obliquity in the earlier epochs beyond 5 Myr are impossible. We conclude that the period of intensive reshaping of the polar cap and formation of Chasma Boreale occurred 3.5 Myr ago or earlier. During the last 3.5 Myr the cap was rather similar to present; minor erosion and deposition of the upper layers could occur, along with modest trough migration in the short epochs of the highest obliquity. The accumulation of the main mass of the finely layered deposits occurred at least 0.5 - 1 Myr (and may be much earlier) than the Chasma Boreale flood. The accumulation could occur in response to some obliquity-driven climate variation or due to some endogenic discharge of water. The platy unit (Byrne and Murrey, JGR, JE001615, 2002) is the stratigraphically lowest part of the polar cap, and is probably noticeably older than the finely layered unit.

Kreslavsky, M. A.; Head, J. W.

2002-05-01

100

CCMR: Quantifying the Relationship Between Nanofiber Web Pore Characteristics and Electrospinning Time  

NSDL National Science Digital Library

Nonwoven, electrospun nanofibers have enjoyed increased research attention for many of their unique electrical, optical and mechanical properties; high surface to volume ratio; and ability to be designed to display a desired surface charge. In order to aid future research involving filtration and particle detection, the goal of this study was to quantify pore characteristics of polyvinyl alcohol (PVA) fabrics spun for low times. The two methods used were capillary flow porometry and scanning electron microscope image analysis. 8, 10 and 12 w% solutions of PVA with maleic anhydride (MA) and Polybrene additives for surface charge were spun at 0.01 mL/min with a 15 cm collecting distance and an applied charge of 12kV. The 10 w% for both solutions had better spinnability and fiber uniformity, although the PVA/MA had significantly greater fiber diameter uniformity over the PVA/Polybrene solution. The porometer returned a range of 30.9 μm to 3.3 μm and the image analysis a range of about 6 μm to 1 μm from 5 seconds to 5 minutes. Although capillary flow porometry cannot measure porosity, SEM image analysis found that the porosity of both solutions was reduced from 80% at 5 seconds to only 28% at 5 minutes. The uniformity of pores became apparent with roughly 1 minute of spinning time and increased with times greater than 1 minute.

Luginbuhl, Kelli M.

2010-08-15

101

Prediction of Carcass Characteristics by Real-Time Ultrasound in Barrows and Gilts Slaughtered at Three Weights1  

Microsoft Academic Search

The carcass characteristics of 27 market barrows and 27 market gilts were evalu- ated at various times (n = 8) with real-time ultrasound (Aloka 210 DXI from approximately 20 kg until slaughter at three end points. The pigs were randomly assigned to slaughter weight groups of 91, 104.5, and 118 kg at weaning time. Correlations were determined over slaughter weight

B. S. Smithz; W. R. Jones; J. D. Hough; D. L. Huffman; W. B. MikeP; D. R. Mulvaney

2010-01-01

102

Visualization of Dynamic Characteristics in Two-Dimensional Time Series Patterns: An Application to Online Signature Verification  

Microsoft Academic Search

\\u000a An analysis model for the dynamics information of two-dimensional time-series patterns is described. In the proposed model,\\u000a two novel transforms that visualize the dynamic characteristics are proposed. The first transform, referred to as speed equalization,\\u000a reproduces a time-series pattern assuming a constant linear velocity to effectively model the temporal characteristics of\\u000a the signing process. The second transform, referred to as

Suyoung Chi; Jaeyeon Lee; Jung Soh; Dohyung Kim; Oh Weongeun; Changhun Kim

2003-01-01

103

Experimental investigation on channel characteristics in tunnel environment for Time Reversal Ultra Wide Band techniques  

NASA Astrophysics Data System (ADS)

The objective of this paper is to investigate the potential advantages of the Time Reversal (TR) technique applied to Impulse Radio Ultra Wide Band (UWB) signals for communications in tunnels. Indeed, in an environment with significant multipaths, it has already been outlined that this technique allows mitigating intersymbol interference and increases the peak power received at a target antenna. However, in a tunnel, as a result of the guiding effect of the structure, the spatial diversity degree decreases as the distance between the transmitter and receiver increases. An in-depth analysis is therefore needed, and we first thus present the main characteristics of the UWB channel deduced from measurements made in a long straight arched tunnel and for a frequency band extending from 2.8 to 5 GHz. In the time domain, waveforms of the impulse radio signal are obtained through an inverse Fourier transform of the measured frequency response and examples are given for different distances varying from 50 m to 500 m. Delay spread and peak-to-peak gain are then studied, depending on the communication range. The case for multiple antenna transmission is also considered.

Garcia-Pardo, Concepcion; Lienard, Martine; Degauque, Pierre; Molina-Garcia-Pardo, Jose-Maria; Juan-LláCer, Leandro

2012-02-01

104

Using centroid time-delays to characterize source durations and identify earthquakes with unique characteristics  

NASA Astrophysics Data System (ADS)

The relationship between M0 and the rupture duration is often difficult to establish. This is particularly true for large earthquakes for which the moment rate functions (MRF) generally have complicated shapes, and the estimated durations can vary considerably depending on the methodology used to evaluate the MRF. In this work, we show that the centroid time-delay (?c) provides an alternative estimate of the source duration. Inverted MRFs often end gradually, making the end of coseismic rupture difficult to detect. In such cases, when the rupture duration is not well defined, the time-delay ?c is a useful quantity to represent the first-order temporal characteristics of the rupture process. Variations in stress parameter ?? can be investigated by assuming a standard scaling relationship between the seismic moment M0 and ?c. This simple scaling relationship can also be used to identify unusual earthquakes, with unique source properties, such as events involving complicated rupture processes or earthquakes characterized by unusual rupture velocities, stress drops or aspect ratios.

Duputel, Zacharie; Tsai, Victor C.; Rivera, Luis; Kanamori, Hiroo

2013-07-01

105

Can the timing-characteristics of phonocardiographic signal be used for cuffless systolic blood pressure estimation?  

PubMed

Continuous and non-invasive measurement of blood pressure (BP) is always important to critically ill patients. To achieve continuous and cuffless BP monitoring, pulse transit time (PTT) has been reported as a potential parameter. Recently a novel parameter RS2 (defined as the time interval measured from the R wave of electrocardiographic (ECG) signal to the peak of second heart sound of phonocardiographic (PCG) signal) is proposed for the same purpose. In this study, the relationship between systolic BP (SBP) and PTT as well as the relationship between SBP and RS2 on 25 healthy subjects, aged 24 +/- 3 years, were compared after exercise. The results in current study showed that SBP is correlated with both PTT and RS2, where the mean individual correlations are r=-0.95 and r=-0.85 respectively. The mean standard deviation of the differences between the measured SBP and the SBP predicted from the regression lines in scatter plots of SBP~PTT and SBP~RS2 are 4.1 mmHg and 7.2 mmHg respectively. In summary, the results showed that RS2 is possible to be used for continuous and non-invasive monitoring of SBP after exercise. In the future, it is important to investigate more robust techniques for locating characteristic points on the PCG signals. PMID:17946987

Wong, M Y M; Poon, C C Y; Zhang, Y T

2006-01-01

106

Permeability models of porous media: Characteristic length scales, scaling constants and time-dependent electrokinetic coupling  

NASA Astrophysics Data System (ADS)

Four important models that describe the fluid permeability of geological porous media and that are derived from different physical approaches have been rewritten in a generic form that implies a characteristic scale length and scaling constant for each model. The four models have been compared theoretically and using experimental data from 22 bead packs and 188 rock cores from a sand-shale sequence in the UK sector of the North Sea. The Kozeny-Carman model did not perform well because it takes no account of the connectedness of the pore network, and should no longer be used. The other three models (Schwartz, Sen and Johnson (SSJ), Katz and Thompson (KT) and the so-called RGPZ) all performed well when used with their respective length scales and scaling constants. Surprisingly, we have found that the SSJ and KT models are extremely similar, such that their characteristic scale lengths and scaling constants are almost identical even though they are derived using extremely different approaches; the SSJ model by weighting the Kozeny-Carman model using the local electric field, the KT model using entry radii from fluid imbibition measurements. The experimentally determined scaling constants for each model were found to be cSSJ ? cKT ? 8/3 ? cRGPZ/3. Use of these models with AC electrokinetic theory has also allowed us to show that these scaling constants are also related to the a value in the RGPZ model and the m* value in time-dependent electrokinetic theory, and then derive a relationship between the electrokinetic transition frequency and the RGPZ scale length, which we have validated using experimental data. The practical implication of this work for permeability prediction is that the Katz and Thompson model should be used when fluid imbibition data is available, while the RGPZ model should be used when electrical data is available.

Glover, Paul; Walker, Emile

2010-05-01

107

Characteristics of first-time fathers of advanced age: a Norwegian population-based study  

PubMed Central

Background The modern phenomenon of delayed parenthood applies not only to women but also to men, but less is known about what characterises men who are expecting their first child at an advanced age. This study investigates the sociodemographic characteristics, health behaviour, health problems, social relationships and timing of pregnancy in older first-time fathers. Methods A cross-sectional study was conducted of 14 832 men who were expecting their first child, based on data from the Norwegian Mother and Child Cohort Study (MoBa) carried out by the Norwegian Institute of Public Health. Data were collected in 2005–2008 by means of a questionnaire in gestational week 17–18 of their partner’s pregnancy, and from the Norwegian Medical Birth Register. The distribution of background variables was investigated across the age span of 25 years and above. Men of advanced age (35–39 years) and very advanced age (40 years or more) were compared with men aged 25–34 years by means of bivariate and multivariate logistic regression analyses. Results The following factors were found to be associated with having the first child at an advanced or very advanced age: being unmarried or non-cohabitant, negative health behaviour (overweight, obesity, smoking, frequent alcohol intake), physical and mental health problems (lower back pain, cardiovascular diseases, high blood pressure, sleeping problems, previous depressive symptoms), few social contacts and dissatisfaction with partner relationship. There were mixed associations for socioeconomic status: several proxy measures of high socioeconomic status (e.g. income >65 000 €, self-employment) were associated with having the first child at an advanced or very advanced age, as were several other proxy measures of low socioeconomic status (e.g. unemployment, low level of education, immigrant background).The odds of the child being conceived after in vitro fertilisation were threefold in men aged 34–39 and fourfold from 40 years and above. Conclusions Men who expect their first baby at an advanced or very advanced age constitute a socioeconomically heterogeneous group with more health problems and more risky health behaviour than younger men. Since older men often have their first child with a woman of advanced age, in whom similar characteristics have been reported, their combined risk of adverse perinatal outcomes needs further attention by clinicians and researchers.

2013-01-01

108

NOISE CHARACTERISTIC AND SEASONAL SIGNALS IN THE RE-PROCESSED EUREF PERMANENT NETWORK COORDINATE TIME SERIES  

NASA Astrophysics Data System (ADS)

Previous analyses of periodic signals present in continuous GPS time series showed that the amplitude and phase of the derived seasonal term mostly disagree with surface mass loading models. The CGPS results appeared to over-estimate the amplitude of the seasonal term and the estimated amplitudes and/or phases were poorly coherent with the loading models, especially at sites close to coastal areas. The studies concluded that the GPS results are distorted by analysis artifacts (such as ocean tide loading, aliasing, and antenna phase centre variation models), monument thermal effects, and multipath. In addition, the actual CGPS time series were inhomogeneous in terms of processing strategy, applied models and reference frame alignment. With the introduction of absolute antenna phase centre variation models an effort, within the EUREF Permanent Network, was initiated to produce a complete GPS re-analysis from global to local levels. A test re-processing of all EPN observations from 1996 to 2007 has already been completed by the Military University of Technology (MUT), Warsaw, Poland and cumulative EPN solutions, from the daily SINEX files, have been created using the CATREF software. We used a combination of Weighted Least Squares, Maximum Likelihood Estimation (MLE), Empirical Orthogonal Functions (EOF’s) and Wavelets to analyze the data for their spatial and temporal noise characteristics and investigate the periodic signals. We find that the noise levels in the re-processed daily solutions is reduced compared to past solutions, but the noise spectra is still represented by a combination of flicker noise and white noise. The amplitudes of the seasonal term have generally decreased and the spatial distribution of the phase lag appears to be more uniform. Comparisons of the estimated annual variations with combined loading models (NCEP + LaD - World - Fraser + ECCO) and the vertical displacement model of the GRACE R4 gravity fields show an improved agreement indicating that some analysis artifacts have been successfully excluded and a clearer view of real geophysical variations is possible.

Kenyeres, A.; Williams, S. D.; Figurski, M.; van Dam, T. M.; Szafranek, K.

2009-12-01

109

Effect of Time on Feed on Performance of Feedlot Steers, Carcass Characteristics, and Tenderness and Composition of Longissimus Muscles  

Microsoft Academic Search

~~ ABSTRACT: Two hundred fifty-six British and feed. Marbling score and the percentage of cattle Continental crossbred yearling steers (329 kg ini- grading U.S. Choice increased (linearly; P < .01) with tially) were fed to study the effect of time on feed on time on feed but at a decreasing rate (quadratic; P < live performance, carcass characteristics, tissue com-

M. T. Van Koevering; D. R. Gill; F. N. Owens; H. G. Dolezal; C. A. Strasia

2010-01-01

110

Colon transit time according to physical activity and characteristics in South Korean adults  

PubMed Central

AIM: To investigate factors contributing to the colon transit time (CTT), physical activity and characteristics were examined. METHODS: Forty-seven Korean adults (males, n = 23; females, n = 24) took a capsule containing 20 radio-opaque markers to measure the CTT. The subjects used an accelerometer to measure the physical activity and underwent a bioelectrical impedance analysis to determine the physical characteristics. Macro-nutrient was also surveyed. RESULTS: The mean total CTTs (TCTT) in the males and females were 8.8 and 24.7 h (P = 0.002), respectively. In the male subjects, the right CTT (3.5 ± 4.9 h vs 10.0 ± 11.6 h, P = 0.023) and recto-sigmoid CTT (4.4 ± 4.7 vs 13.6 ± 12.5 h, P = 0.004) were significantly shorter and the total energy expenditure (637.6 ± 44.3 kcal vs 464.3 ± 64.9 kcal, P = 0.003), total activity count (247?017 ± 75?022 count vs 178?014 ± 75?998 count, P = 0.003), energy expenditure of light intensity (148.5 ± 6.9 kcal vs 120.0 ± 16.8 kcal, P = 0.006), energy expenditure of moderate intensity (472.0 ± 36.2 kcal vs 281.4 ± 22.2 kcal, P < 0.001), fat intake (65.5 ± 23.3 g vs 51.2 ± 17.4 g, P = 0.010), and water consumption (1714.3 ± 329.4 g vs 1164.7 ± 263.6 g, P = 0.009) were significantly higher than in the female subjects. Regarding correlations, when adjusted for gender, fiber (r = -0.545, P < 0.001) and water intake (r = -0.257, P < 0.05) correlated significantly with the TCTT in all subjects. In addition, the body mass index (r = -0.424, P < 0.05) and fiber intake (r = -0.417, P < 0.05) in the males as well as the fiber intake (r = -0.655, P < 0.001) in the females showed significant correlations with the TCTT. CONCLUSION: The subjects showed significant gender differences in the TCTT, right CTT, and recto-sigmoid CTT. Furthermore, the intake of the fiber and water contributed to the CTT.

Cho, Kang Ok; Jo, Yun Ju; Song, Bong Kil; Oh, Jung Woo; Kim, Yeon Soo

2013-01-01

111

Identification of land-cover characteristics using MODIS time series data: an application in the Yangtze river estuary.  

PubMed

Land-cover characteristics have been considered in many ecological studies. Methods to identify these characteristics by using remotely sensed time series data have previously been proposed. However, these methods often have a mathematical basis, and more effort is required to better illustrate the ecological meanings of land-cover characteristics. In this study, a method for identifying these characteristics was proposed from the ecological perspective of sustained vegetation growth trend. Improvement was also made in parameter extraction, inspired by a method used for determining the hyperspectral red edge position. Five land-cover types were chosen to represent various ecosystem growth patterns and MODIS time series data were adopted for analysis. The results show that the extracted parameters can reflect ecosystem growth patterns and portray ecosystem traits such as vegetation growth strategy and ecosystem growth situations. PMID:23894594

Zhang, Mo-Qian; Guo, Hai-Qiang; Xie, Xiao; Zhang, Ting-Ting; Ouyang, Zu-Tao; Zhao, Bin

2013-07-24

112

3D-1 Absolute Transit Time Detection for Ultrasonic Gas Flowmeters Based on Time and Phase Domain Characteristics  

Microsoft Academic Search

We present an absolute transit time detection algorithm for ultrasonic gas flowmeters (UFMs). The major objective is a reliable and accurate detection, even when the received signals experience a change and degradation of their shape. This can be due to parasitic effects, such as high gas temperatures and pressure fluctuations. We employ a time and phase domain based detection algorithm

Mario Kupnik; Edwin Krasser; M. Groschl

2007-01-01

113

Clinicopathologic Characteristics of Gastric Cancer Patients according to the Timing of the Recurrence after Curative Surgery  

PubMed Central

Purpose There are few studies that have focused on the predictors of recurrence after gastrectomy for gastric carcinoma. This study analyzed the patients who died of recurrent gastric carcinoma and we attempted to clarify the clinicopathologic factors that are associated with the timing of recurrence. Materials and Methods From June 1992 to March 2009, 1,795 patients underwent curative gastric resection at the Department of Surgery, Hanyang University College of Medicine. Among them, 428 patients died and 311 of these patients who died of recurrent gastric carcinoma were enrolled in this study. The clinicopathologic findings were compared between the 72 patients who died within one year after curative gastrectomy (the early recurrence group) and the 92 patients who died 3 years after curative gastrectomy (the late recurrence group). Results Compared with the late recurrence group, the early recurrence group showed an older age, a more advanced stage, a poorly differentiated type of cancer and a significantly higher tendency to have lymphatic invasion, vascular invasion and perineural invasion.Especially in the gastric cancer patients with a more advanced stage (stage III and IV), the early recurrence group was characterized by a significantly higher preoperative serum carcino embryonic antigen level, perineural invasion and a relatively small number of dissected lymph nodes. Conclusions The clinicopathologic characteristics of recurrent gastric cancer are significantly different according to the stage of disease, and even in the same stage. For the early detection of recurrence after curative surgery, it is important to recognize the clinicopathological factors that foretell a high risk of recurrence. It is mandatory to make an individualized surveillance schedule according to the clinicopathologic factors.

Choi, Ji Yoon; Ha, Tae Kyung

2011-01-01

114

Investigation of doped calcium aluminosilicate glass: A coupling between thermal-expansion and thermal-diffusion models for assessment of nonradiative relaxation time and characteristic diffusion time  

Microsoft Academic Search

This paper discusses the use of photoacoustic models to obtain the nonradiative relaxation time (?) and characteristic diffusion time (??) for a sample showing visible absorption bands from fluorescent ion-doped low-silica calcium aluminosilicate glass. Two models allowing phase shift analyses, the thermal-expansion and thermal-diffusion models, are briefly reviewed. These models have limitations when the photoacoustic signal depends on both factors,

N. E. Souza Filho; A. C. Nogueira; J. H. Rohling; M. L. Baesso; A. N. Medina; A. P. L. Siqueira; J. A. Sampaio; H. Vargas; A. C. Bento

2009-01-01

115

Investigation of doped calcium aluminosilicate glass: A coupling between thermal-expansion and thermal-diffusion models for assessment of nonradiative relaxation time and characteristic diffusion time  

Microsoft Academic Search

This paper discusses the use of photoacoustic models to obtain the nonradiative relaxation time (tau) and characteristic diffusion time (taubeta) for a sample showing visible absorption bands from fluorescent ion-doped low-silica calcium aluminosilicate glass. Two models allowing phase shift analyses, the thermal-expansion and thermal-diffusion models, are briefly reviewed. These models have limitations when the photoacoustic signal depends on both factors,

N. E. Souza Filho; A. C. Nogueira; J. H. Rohling; M. L. Baesso; A. N. Medina; A. P. L. Siqueira; J. A. Sampaio; H. Vargas; A. C. Bento

2009-01-01

116

Characteristic impedance and propagation of the first higher order microstrip mode in frequency and time domain  

Microsoft Academic Search

This paper experimentally and theoretically confirms the validity of the definition proposed by Das (1996) for computing the complex characteristic impedance of the first higher order (EH1) microstrip mode. The normalized complex propagation constant and complex characteristic impedance of the microstrip obtained by the rigorous full-wave integral-equation method are also presented. To better understand the circuit behavior of the leaky

Shyue-Dar Chen; Ching-Kuang C. Tzuang

2002-01-01

117

Assessing the Value of Regulation Resources Based on Their Time Response Characteristics  

SciTech Connect

Fast responsive regulation resources are potentially more valuable as a power system regulation resource (more efficient) because they allow applying controls at the exact moment and in the exact amount as needed. Faster control is desirable because it facilitates more reliable compliance with the NERC Control Performance Standards at relatively lesser regulation capacity procurements. The current California ISO practices and markets do not provide a differentiation among the regulation resources based on their speed of response (with the exception of some minimum ramping capabilities). Some demand response technologies, including some generation and energy storage resources, can provide quicker control actions. California ISO practices and markets could be updated to welcome more fast regulation resources into the California ISO service area. The project work reported in this work was pursuing the following objectives: • Develop methodology to assess the relative value of generation resources used for regulation and load following California ISO functions • This assessment should be done based on physical characteristics including the ability to quickly change their output following California ISO signals • Evaluate what power is worth on different time scales • Analyze the benefits of new regulation resources to provide effective compliance with the mandatory NERC Control Performance Standards • Evaluate impacts of the newly proposed BAAL and FRR standards on the potential value of fast regulation and distributed regulation resources • Develop a scope for the follow-up projects to pave a road for the new efficient types of balancing resources in California. The work included the following studies: • Analysis of California ISO regulating units characteristics • California ISO automatic generation system (AGC) analysis • California ISO regulation procurement and market analysis • Fast regulation efficiency analysis • Projection of the California ISO load following and regulation requirements into the future • Value of fast responsive resources depending on their ramping capability • Potential impacts of the balancing authority area control error limit (BAAL), which is a part of the newly proposed NERC standard “Balancing Resources and Demand” • Potential impacts of the Western Electricity Coordinating Council (WECC) frequency responsive reserve (FRR) standard • Recommendations for the next phase of the project. The following main conclusions and suggestions for the future have been made: • The analysis of regulation ramping requirements shows that the regulation system should be able to provide ramps of at least 40-60 MW per minute for a period up to 6 minutes. • Evaluate if changes are needed in the California ISO AGC system to effectively accommodate new types of fast regulation resources and minimize the California ISO regulation procurement. • California ISO may consider creating better market opportunities for and incentives for fast responsive resources. • An additional study of low probability high ramp events can be recommended to the California ISO. • The California ISO may be willing to consider establishing a more relaxed target CPS2 compliance level. • A BAAL-related study can be recommended for the California ISO as soon as more clarity is achieved concerning the actual enforcement of the BAAL standard and its numerical values for the California ISO. The study may involve an assessment of advantages of the distributed frequency-based control for the California ISO system. The market-related issues that arise in this connection can be also investigated. • A FRR-related study can be recommended for the California ISO as soon as more clarity is achieved concerning the actual enforcement of the FRR standard and its numerical values for the California ISO.

Makarov, Yuri V.; Lu, Shuai; Ma, Jian; Nguyen, Tony B.

2008-06-01

118

Time-of-Flight Method Usage for Measurng Energy and Time Characteristics of a Beam from Cyclotron U-240.  

National Technical Information Service (NTIS)

Energy of beam, extracted from cyclotron U-240, was measured on the base of time-of-flight faclity. This technique allows to observe the phase instability of the accelerated particle bunch. A conclusion about necessity of the permanent control for beam sp...

V. I. Grantsev I. P. Dryapachenko V. I. Konfederatenko B. A. Rudenko M. V. Sokolov

1983-01-01

119

Nitrifier characteristics in submerged membrane bioreactors under different sludge retention times.  

PubMed

Three submerged membrane bioreactors (MBRs) were operated continuously for 230 days by feeding with synthetic inorganic wastewater (NH(4)(+)-N, 100 mg L(-1)) under different solids retention times (SRTs. M(30d), 30 days; M(90d), 90 days; M(infinite), no sludge purge) to examine the influence of SRT on nitrification performance and microbial characteristics. All the reactors could oxidize NH(4)(+)-N to NO(3)(-)-N effectively without accumulation of NO(2)(-)-N. M(30d) with the shortest SRT showed significantly higher specific ammonium oxidizing rate (SAOR, 0.22 kg NH(4)(+)-N kg(-1) MLSS day(-1)) and specific nitrate forming rate (SNFR, 0.13 kg NO(3)(-)-N kg(-1) MLSS day(-1)) than the other two MBRs (0.12-0.14 kg NO(3)(-)-N kg(-1) MLSS day(-1) and 0.042-0.068kg NO(3)(-)-N kg(-1) MLSS day(-1), respectively). Short SRT led to low extracellular polymeric substances (EPS) concentration and long operating cycle. The nitrite oxidizing bacteria (NOB) ratios by both the fluorescence in situ hybridization (FISH) (3.6% for M(30d) and 2.1-2.2% for M(90d) and M(infinite)) and MPN (1.4 x 10(7)cells g(-1) MLSS for M(30d) and 6.2 x 10(5) and 2.7 x 10(4)cells g(-1) MLSS for M(90d) and M(infinite)) analyses showed that M(30d) favored the accumulation of NOB, which was in accordance with the SNFR result. However, the ammonia oxidizing bacteria (AOB) ratios (3.5%, 3.2% and 4.9% for M(30d), M(90d) and M(infinite)) were not in accordance with the SAOR result. PCR-DGGE, clone library and FISH results showed that the fast-growing Nitrosomonas and Nitrobacter sp. were the dominant AOB and NOB, respectively for M(30d), while considerable slow-growing Nitrosospira and Nitrospira sp. existed in M(infinite), which might be an important reason why M(infinite) had a low SAOR and SNFR. PMID:20227741

Yu, Tao; Qi, Rong; Li, Dong; Zhang, Yu; Yang, Min

2010-02-21

120

Operational characteristic analysis of conduction cooling HTS SMES for Real Time Digital Simulator based power quality enhancement simulation  

NASA Astrophysics Data System (ADS)

This paper analyzes the operational characteristics of conduction cooling Superconducting Magnetic Energy Storage (SMES) through a real hardware based simulation. To analyze the operational characteristics, the authors manufactured a small-scale toroidal-type SMES and implemented a Real Time Digital Simulator (RTDS) based power quality enhancement simulation. The method can consider not only electrical characteristics such as inductance and current but also temperature characteristic by using the real SMES system. In order to prove the effectiveness of the proposed method, a voltage sag compensation simulation has been implemented using the RTDS connected with the High Temperature Superconducting (HTS) model coil and DC/DC converter system, and the simulation results are discussed in detail.

Kim, A. R.; Kim, G. H.; Kim, K. M.; Kim, D. W.; Park, M.; Yu, I. K.; Kim, S. H.; Sim, K.; Sohn, M. H.; Seong, K. C.

2010-11-01

121

Time-Structured and Net Intraindividual Variability: Tools for Examining the Development of Dynamic Characteristics and Processes  

PubMed Central

The study of intraindividual variability is the study of fluctuations, oscillations, adaptations, and “noise” in behavioral outcomes that manifest on micro-time scales. This paper provides a descriptive frame for the combined study of intraindividual variability and aging/development. At the conceptual level, we highlight that the study of intraindividual variability provides access to dynamic characteristics – construct-level descriptions of individuals' capacities for change (e.g., lability), and dynamic processes – the systematic changes individuals' exhibit in response to endogenous and exogenous influences (e.g., regulation). At the methodological level, we review how quantifications of net intraindividual variability (e.g., iSD) and models of time-structured intraindividual variability (e.g., time-series) are being used to measure and describe dynamic characteristics and processes. At the research design level, we point to the benefits of measurement burst study designs, wherein data are obtained across multiple time scales, for the study of development.

Ram, Nilam; Gerstorf, Denis

2009-01-01

122

Effects of fatigue and recovery on electromyographic and isometric force- and relaxation-time characteristics of human skeletal muscle  

Microsoft Academic Search

Summary  Effects of fatigue produced by a maintained 60% isometric loading on electromyographic and isometric force-time and relaxation-time characteristics of human skeletal muscle were studied in 21 males accustomed to strength training. Fatigue loading resulted in a slight but not significant change in the maximal integrated EMG of a maximal isometric contraction, and a large decrease (20.4±6.3%, pppppppp

Keijo HÄkkinen; Paavo V. Komi

1986-01-01

123

The Fluorescence Characteristics of Enrichment Media in the Wavelength Range of Real-Time PCR Thermocycler Optical Path Assignments  

Microsoft Academic Search

The aim of this study was to investigate the fluorescence characteristics of common enrichment media with regard to disturbance\\u000a of fluorescence readings of real-time polymerase chain reaction (PCR) reactions. Confirmation of effective amplification of\\u000a target DNA during the real-time PCR process depends on measurement of the fluorescence emitted from the probe fluorophore\\u000a used. Possible background fluorescence emitted from enrichment media,

Peter Rossmanith; Sabine Fuchs; Martin Wagner

2010-01-01

124

Some fundamental characteristics of the one-dimensional alternate-direction-implicit finite-difference time-domain method  

Microsoft Academic Search

Some fundamental characteristics are investigated for the alternate-direction-implicit finite-difference time-domain (ADI-FDTD) method in the one-dimensional case, such as growth and dissipation, numerical dispersion, and a time-step size limit. It is shown that this two sub-step method alternates dissipation and growth that exactly compensate and, thus, is unconditionally stable. The numerical dispersion error is larger than for Yee's method and there

Guilin Sun; Christopher W. Trueman

2004-01-01

125

Effect of time of oviposition on egg quality characteristics in cages and in a litter housing system  

Microsoft Academic Search

Two experiments were carried out to investigate the effect of the time of oviposition on egg quality characteristics in two different housing systems (cages vs. litter). ISA brown hens from 20 to 64 weeks of age were housed in battery cages (550 cm 2 \\/hen, 19 526 laying hens in the house) and on deep litter (7 hen\\/m 2 ,

E. T?MOVÁ; T. EBEID

2005-01-01

126

Direct measurement of the characteristic three-body electron attachment time in the atmospheric air in direct current electric field  

NASA Astrophysics Data System (ADS)

We report the results of theoretical and experimental study of the characteristic time for three-body attachment of electrons produced by 100 fs UV laser pulse in the atmosphere air in the external DC electric field ranged from 0.2 to 10 kV/cm.

Shutov, A. V.; Smetanin, I. V.; Ionin, A. A.; Levchenko, A. O.; Seleznev, L. V.; Sinitsyn, D. V.; Ustinovskii, N. N.; Zvorykin, V. D.

2013-07-01

127

Are Middle Schools Harmful? The Role of Transition Timing, Classroom Quality and School Characteristics  

ERIC Educational Resources Information Center

|Are middle schools ill-suited for early adolescents, or can school characteristics account for any differences in student functioning? Achievement, school engagement, and perceived competence of children starting middle schools in 5th and 6th grades were compared to those of their same-grade peers in elementary schools in a national, longitudinal…

Holas, Igor; Huston, Aletha C.

2012-01-01

128

Electric assisted bicycles and measurement of real-time performance characteristics for power management strategies  

Microsoft Academic Search

Electric assisted bicycles can offer a cost effective alternative for commuter applications. However there is limited knowledge about the operating characteristics of such bicycles, which is necessary to optimize the rating of energy storage as it can significantly affect their range and weight. This study examines and realises an alternative design for a wheel hub direct drive. The paper also

Stuart Brand; S. Bakhri; N. Ertugrul

2007-01-01

129

Spending Time with Teacher: Characteristics of Preschoolers Who Frequently Elicit versus Initiate Interactions with Teachers.  

ERIC Educational Resources Information Center

|Explored interface between preschoolers' socio-emotional characteristics and interactions with teachers during free play. Found that children who most frequently initiated teacher interaction behaved more aggressively than peers and were so rated by teachers. Children who most frequently received teacher initiations were more shy and anxious.…

Coplan, Robert J.; Prakash, Kavita

2003-01-01

130

The latency operating characteristic: II. Effects of visual stimulus intensity on choice reaction time  

Microsoft Academic Search

Studied the effect of stimulus intensity on the latency operating characteristic (LOC), the trade-off relation between speed and accuracy. Stimuli were presented to 4 male and 1 female undergraduate at 3 intensities that differed by equal intervals on a logarithmic scale. Both the slope and intercept of a linear relation between RT and discrimination accuracy (d') varied with stimulus intensity:

Joseph S. Lappin; Kenneth Disch

1972-01-01

131

First Time: Characteristics of Teens' First Sexual Relationships. Child Trends Research Brief.  

ERIC Educational Resources Information Center

|Understanding characteristics of teens' sexual relationships may help us to better understand how to reduce teens' risk of early unintended pregnancy and sexually transmitted diseases (STDs), as well as the psychological and emotional problems that may be associated with teenage romantic relationships and sexual activity. Using data from the…

Ryan, Suzanne; Manlove, Jennifer; Franzetta, Kerry

132

Effect of micro-grooved surface on the flow structure in laminar-turbulent transition  

Microsoft Academic Search

The micro-grooves (or riblets) parallel to the flow streamline have been discovered to reduce surface drag for turbulent boundary layer in the range of 5 < h+ < 25 with a maximum drag reduction of 8%. The drag reduction was suggested to be the confinement of near-wall flow motion. To investigate the drag reduction mechanism, an experimental program was conducted

Chia-Liu Kuan

1998-01-01

133

Selective Influence of Circadian Modulation and Task Characteristics on Motor Imagery Time  

ERIC Educational Resources Information Center

|In this study, we examined the effect of circadian modulation on motor imagery (MI) time while also considering the effects of task complexity and duration. The ability to imagine in real time was influenced by circadian modulation in a simple walking condition, with longer MI times in the morning and evening sessions. By contrast, there was no…

Debarnot, Ursula; Sahraoui, Djafar; Champely, Stephane; Collet, Christian; Guillot, Aymeric

2012-01-01

134

CHARACTERISTICS OF TIME SYNCHRONIZATION RESPONSE OF NTP CLIENTS ON MS WINDOWS OS AND LINUX OS  

Microsoft Academic Search

The clock offset between a GPS-based NTP time server and NTP time client software, installed in the MS Windows Operating System (OS) and the Linux OS on PCs, are measured and evaluated. The clock offset on MS Windows 98 OS shows a trend with a range of about 55 ms. The NTP time client software on MS Windows OS adjusts

Katsuhisa Sato; Kazuyoshi Asari

135

Differentiating Blood, Lymph, and Primo Vessels by Residual Time Characteristic of Fluorescent Nanoparticles in a Tumor Model  

PubMed Central

Fluorescent nanoparticles (FNPs) which were injected into a tumor tissue flowed out through the blood and lymph vessels. The FNPs in blood vessels remained only in the order for few minutes while those in lymph vessels remained for a long time disappearing completely in 25 hours. We found a primo vessel inside a lymph vessel near a blood vessel, and FNPs remained in the primo vessel for longer than 25 hours. In addition, we examined in detail the residual time characteristics of lymph vessels because it could be useful in a future study of fluid dynamical comparison of the three conduits. These residual time characteristics of FNPs in the three kinds of vessels may have implications for the dynamics of nanoparticle drugs for cancer chemotherapy.

Lee, Sungwoo; Lim, Jaekwan; Cha, Jinmyung; Lee, Jin-Kyu; Ryu, Yeon Hee; Kim, SungChul; Soh, Kwang-Sup

2013-01-01

136

Evaluation of timing characteristics of a prototype system based on PROFINET IO RT_Class 3  

Microsoft Academic Search

The PROFINET architecture can provide real-time, high-performance, isochronous communication regardless the presence of other real-time data exchange and TCP\\/IP traffic for a considerable portion of network bandwidth. In this work some experimental tests have been executed in order to evaluate timing performance of a PROFINET ASIC (ERTEC 400 chip) and its related development kits. Results shows that communication isochrony has

Paolo Ferrari; Alessandra Flammini; Daniele Marioli; Andrea Taroni; Francesco Venturini

2007-01-01

137

Effects of Teacher Wait Time on Discourse Characteristics in Mathematics and Language Arts Classes  

Microsoft Academic Search

Ten classes were randomly assigned to a group that received feedback and assistance to maintain an average teacher wait time of between 3 and 5 seconds during a sequence of mathematics lessons. A control group of 10 teachers maintained a regular wait time and received placebo feedback. The study was replicated in a sequence of language arts lessons. The use

Kenneth Tobin

1986-01-01

138

Effects of extended wait time on discourse characteristics and achievement in middle school grades  

Microsoft Academic Search

The study was conducted in 20 intact classes in grades 6 and 7 from suburban schools in Perth, Australia. The study investigated changes in discourse attributable to the use of an extended teacher wait time in a sequence of seven lessons related to probabilistic reasoning. A wait time feedback group of 10 classes obtained a significantly higher summative achievement mean

Kenneth Tobin

1984-01-01

139

Chemical Modification of ProRoot MTA to Improve Handling Characteristics and Decrease Setting Time  

Microsoft Academic Search

Mineral trioxide aggregate (MTA) fulfills many of the ideal properties of a root-end filling material. However, the composition of this material often makes MTA difficult to use, a direct result of its granular consistency, slow setting time, and initial looseness. Additives used by the Portland cement (PC) industry to increase PC’s plasticity and decrease its setting time were added first

Benjamin S. Ber; John F. Hatton; Gregory P. Stewart

2007-01-01

140

The Effects of Family Characteristics and Time Use on Teenagers' Household Labor.  

ERIC Educational Resources Information Center

Longitudinal data collected from teenagers were analyzed for types of household chores the teens perform. The study determined that girls devoted more time to household tasks than boys, while both their efforts were greater in larger families and single-parent families. High school males spent more time on extracurricular and leisure activities,…

Gager, Constance T.; Cooney, Teresa M.; Call, Kathleen Thiede

1999-01-01

141

Effects of Extended Wait Time on Discourse Characteristics and Achievement in Middle School Grades.  

ERIC Educational Resources Information Center

Investigated changes that occurred in sixth- and seventh-grade teacher and student discourse when teachers endeavored to implement extended teacher wait-time in a sequence of seven lessons related to probabilistic reasoning. Results indicated that teacher wait-time increased from an average of 1.9 to 4.4 seconds during the lesson sequence. (JN)

Tobin, Kenneth

1984-01-01

142

Space - time diaries and travel characteristics for different levels of respondent aggregation  

Microsoft Academic Search

Significant progress has been made in the analysis of space - time diary data. Drawing on the flexibility that such data provide, in this study the authors group respondents at five different levels of aggregation, and compare them according to their mean and standard deviation values for selected measures of travel behaviour. The measures, derived from the time - geography

D G Janelle; M F Goodchild; B Klinkenberg

1988-01-01

143

Characteristics of the Time-Series Data Collected through Curriculum-Based Reading Measurement.  

ERIC Educational Resources Information Center

|Research on the analysis of time-series data has shown that decisions reached through visual analysis of the data may be influenced by the statistical parameters of those data. The current study investigated the statistical properties of curriculum-based time-series data for 68 elementary resource room students in four Minnesota school districts.…

Skiba, Russell; And Others

144

Investigation of doped calcium aluminosilicate glass: A coupling between thermal-expansion and thermal-diffusion models for assessment of nonradiative relaxation time and characteristic diffusion time  

NASA Astrophysics Data System (ADS)

This paper discusses the use of photoacoustic models to obtain the nonradiative relaxation time (?) and characteristic diffusion time (??) for a sample showing visible absorption bands from fluorescent ion-doped low-silica calcium aluminosilicate glass. Two models allowing phase shift analyses, the thermal-expansion and thermal-diffusion models, are briefly reviewed. These models have limitations when the photoacoustic signal depends on both factors, in a coupling mechanism. An alternative model is proposed to take both thermal expansion and thermal diffusion into account with a single temperature solution for the heat-coupled differential equation. This model is simulated for absorbing samples near the thermally thick region. The model is applied to Eu-V codoped glass showing intermediate signal dependence from ?-1.0 to ?-3/2. The nonradiative time and characteristic diffusion time are derived with 33

Souza Filho, N. E.; Nogueira, A. C.; Rohling, J. H.; Baesso, M. L.; Medina, A. N.; Siqueira, A. P. L.; Sampaio, J. A.; Vargas, H.; Bento, A. C.

2009-11-01

145

Characteristic Times of Gradual Solar Energetic Particle Events and Their Dependence on Associated Coronal Mass Ejection Properties  

NASA Astrophysics Data System (ADS)

We use 20 MeV proton intensities from the EPACT instrument on Wind and coronal mass ejections (CMEs) from the LASCO coronagraph on SOHO observed during 1998-2002 to statistically determine three characteristic times of gradual solar energetic particle (SEP) events as functions of solar source longitude: (1) TO, the time from associated CME launch to SEP onset at 1 AU, (2) TR, the rise time from SEP onset to the time when the SEP intensity is a factor of 2 below peak intensity, and (3) TD, the duration over which the SEP intensity is within a factor of 2 of the peak intensity. Those SEP event times are compared with associated CME speeds, accelerations, and widths to determine whether and how the SEP event times may depend on the formation and dynamics of coronal/interplanetary shocks driven by the CMEs. Solar source longitudinal variations are clearly present in the SEP times, but TR and TD are significantly correlated with CME speeds only for SEP events in the best-connected longitude range. No significant correlations between the SEP times and CME accelerations are found except for TD in one longitude range, but there is a weak correlation of TR and TD with CME widths. We also find no correlation of any SEP times with the solar wind O+7/O+6 values, suggesting no dependence on solar wind stream type. The SEP times of the small subset of events occurring in interplanetary CMEs may be slightly shorter than those of all events.

Kahler, S. W.

2005-08-01

146

Effect of weaning status and storage time under vacuum upon physical characteristics of meat of the Rubia Gallega breed.  

PubMed

Seven to nine months old calves are the typical production of Rubia Gallega, which is the most important beef breed in Spain. A study about the influence of weaning status and vacuum storage time on veal quality characteristics is needed. The muscle longissimus thoracis from 22 non-weaned (NW) and 21 weaned (W) calves at 1day post-slaughter, and vacuum packaged for 7 and 14 days were analysed. NW showed higher yellowness and hue values than W but lower pigment concentration. The differences disappeared at longer storage times. The redness, yellowness, hue and chroma increased with aging, but the pigment concentration, expressible juice and toughness decreased with aging. Principal component analysis showed that colour variables were the most determinant characteristics in quality variation. The canonical discriminant analysis separated the samples in three groups: 1 day post-slaughter W, 1day post-slaughter NW, and vacuum packaged W and NW. PMID:22062059

Oliete, B; Carballo, J A; Varela, A; Moreno, T; Monserrat, L; Sánchez, L

2005-12-28

147

Runoff processes, stream water residence times and controlling landscape characteristics in a mesoscale catchment: An initial evaluation  

Microsoft Academic Search

Tracer studies, using Gran alkalinity and ?18O, in nested sub-basins of the 230km2 Feshie catchment in the Cairngorm mountains, Scotland, were used to characterise hydrology in terms of groundwater contributions to annual runoff and mean residence times. Relationships between these fundamental hydrological descriptors and catchment characteristics were explored with the use of a GIS. Catchment soil distribution—mapped by the UK's

C. Soulsby; D. Tetzlaff; P. Rodgers; S. Dunn; S. Waldron

2006-01-01

148

Time-domain finite difference approach to the calculation of the frequency-dependent characteristics of microstrip discontinuities  

Microsoft Academic Search

The frequency-dependent characteristics of the microstrip discontinuities have previously been analyzed using full-wave approaches. The time-domain finite-difference (TD-FD) method presented here is an independent approach and is relatively new in its application for obtaining the frequency-domain results for microwave components. The validity of the TD-FD method in modeling circuit components for MMIC CAD applications is established.

Xiaolei Zhang; Kenneth K. Mei

1988-01-01

149

[Comparative study on the characteristics of electrocardiac signals in time domain and frequency domain].  

PubMed

There are two methods (time domain and frequency domain) for the analysis of electrocardiac signals. In this paper is reported a study on them by way of comparison. With the use of filtering method in frequency domain, certain low frequency components were filtered, the time domain waveform was retrieved by IFFT, and the biphase T wave appeared in time domain. After some high frequency components were filtered, time domain wave was retrieved by IFFT, and amplified, the time domain representation of high frequency ECS could be shown obviously, i.e. there was no evident structure in time domain representation of high frequency components in P- and T-waves, but there was evident structure in high frequency components in QRS complex. The duration of QRS depended upon high frequency components, and it was prolonged by filtering certain high frequency components. The slurring of QRS complex was caused by increasing high frequency components, on ventricular depolarized QRS-complex, there were both triangular pulse-like and atriangular pulse-like waveforms, and their power spectrum had both types of feature, single peak and inversepower spectrum. There was no regularity in the spectrum of entire cycle, P- and T-waves, but these was some structure in QRS wave. PMID:11791318

He, W

2001-12-01

150

Time-frequency integration characteristics of hearing are optimized for perception of speech-like acoustic patterns.  

PubMed

Several psychoacoustic phenomena such as loudness perception, absolute thresholds of hearing, and perceptual grouping in time are affected by temporal integration of the signal in the auditory system. Similarly, the frequency resolution of the hearing system, often expressed in terms of critical bands, implies signal integration across neighboring frequencies. Although progress has been made in understanding the neurophysiological mechanisms behind these processes, the underlying reasons for the observed integration characteristics have remained poorly understood. The current work proposes that the temporal and spectral integration are a result of a system optimized for pattern detection from ecologically relevant acoustic inputs. This argument is supported by a simulation where the average time-frequency structure of speech that is derived from a large set of speech signals shows a good match to the time-frequency characteristics of the human auditory system. The results also suggest that the observed integration characteristics are learnable from acoustic inputs of the auditory environment using a Hebbian-like learning rule. PMID:23862817

Räsänen, Okko; Laine, Unto K

2013-07-01

151

Correlation of Biological Characteristics of Smolts with Survival and Travel Time, 1987 Technical Report.  

SciTech Connect

The biological characteristics of smolts were examined to determine their effect on estimates of survival in the Columbia and Snake rivers. Freeze branded groups of steelhead trout (Salmo gairdneri) from Lyons Ferry State Fish Hatchery (SFH) and Wells SFH and spring chinook salmon (Oncorhynchus tshawytscha) from Winthrop National Fish Hatchery (NFH) were used to estimate survival. Past estimates of survival, using a ratio of test and control fish recaptured at McNary Dam, have resulted in estimates > 100%, presumably due to some unknown bias. Study objectives were to determine if stress and descaling, degree of smoltification, and prevalence of bacterial kidney disease (BKD) differed among test and control groups of fish, thereby biasing survival estimates. 19 refs., 20 figs., 10 tabs.

Rondorf, Dennis W.; Beeman, John W.; Free, Mary E. (Seattle National Fishery Research Center, Columbia River Field Station, Cook, WA)

1988-06-01

152

Time-domain diffuse optical tomography using analytic statistical characteristics of photon trajectories  

SciTech Connect

The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions. (special issue devoted to multiple radiation scattering in random media)

Konovalov, Aleksandr B; Vlasov, V V [E.I. Zababakhin All-Russian Scientific-Research Institute of Technical Physics, Russian Federal Nuclear Centre, Snezhinsk, Chelyabinsk region (Russian Federation); Kalintsev, A G; Lyubimov, Vladimir V [Research Institute for Laser Physics, St. Petersburg (Russian Federation); Kravtsenyuk, Olga V [Foundation for Research and Technology-Hellas (IESL-FORTH), Institute of Electronic Structure and Lasers, Crete (Greece)

2006-11-30

153

Physical nature of empirical dependences of strength and fracture characteristics of materials on time  

NASA Astrophysics Data System (ADS)

A correlation is established between each of two empirical relationship parameters describing the arrays of the experimental data on long-term strength, creep, high- and low-cycle fatigue, and fatigue crack propagation for tungsten, molybdenum, titanium alloys, and steels. Unambiguous relationships between the parameters within each array allow the required scope of the material testing to be reduced appreciably. The physical essence of the correlations revealed is related to a thermally activated nature of damage processes, which accompany each type of material testing. It is shown that for all types of tests considered it is possible to define the character of dependence between the correlating empirical parameters and fundamental characteristics of thermally activated damage processes.

Krasovskij, A. Ya.; Tot, L.

1994-06-01

154

Characteristics and control response of the TOPAZ 2 reactor system real-time dynamic simulator  

NASA Astrophysics Data System (ADS)

A dynamic simulator of the TOPAZ 2 reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested, and it is able to handle a step decrease of 8 dollars worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ 2 reactor system under both normal and casualty conditions.

Kwok, K. S.

1993-11-01

155

Characteristics and Control Response of the TOPAZ II Reactor System Real-Time Dynamic Simulator  

NASA Astrophysics Data System (ADS)

A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

Kwok, Kwan S.

1994-07-01

156

Double loop control strategy with different time steps based on human characteristics.  

PubMed

This paper proposes a cooperative control strategy in consideration of the force sensitivity of human. The strategy consists of two loops: one is the intention estimation loop whose sampling time can be variable in order to investigate the effect of the sampling time; the other is the position control loop with fixed time step. A high sampling rate is not necessary for the intention estimation loop due to the bandwidth of the mechanoreceptors in humans. In addition, the force sensor implemented in the robot is sensitive to the noise induced from the sensor itself and tremor of the human. Multiple experiments were performed with the experimental protocol using various time steps of the intention estimation loop to find the suitable sampling times in physical human robot interaction. The task involves pull-and-push movement with a two-degree-of-freedom robot, and the norm of the interaction force was obtained for each experiment as the measure of the cooperative control performance. PMID:23366291

Gu, Gwang Min; Lee, Jinoh; Kim, Jung

2012-01-01

157

Characteristics of DUI recidivists: a 12-year follow-up study of first time DUI offenders.  

PubMed

77 individuals convicted of a drinking and driving (DUI) offense were screened for recidivism approximately 12 years following their first offense. At the time of the initial DUI conviction, participants were administered the MAST and the MMPI-2. Participants' drinking history and driving history and arrest at the time of screening and at a 12-year follow-up were also reviewed. The results indicate that, among DUI recidivists, on average 6 years elapsed between their first and second DUI offenses. Driving history prior to the first DUI offense was predictive of later recidivism. The only significant finding from the MAST and MMPI results was that repeat offenders tended to have higher scores on the L and K validity scales of the MMPI. These results are discussed in the context of Jessor's Problem-Behavior Theory and as well their clinical implications for screening and treatment decisions involving first time DUI offenders. PMID:16876960

Cavaiola, Alan A; Strohmetz, David B; Abreo, Sandra D

2006-07-28

158

Time-dependent mechanical characteristics measured through the use of a microindentation technique  

NASA Astrophysics Data System (ADS)

Under accepted simplifications about the linear viscoelastic background of the problem and the time-independent value of the Poisson’s ratio, this paper aims to compare the short-term histories of the viscoelastic functions of a common time-dependent material, e.g. viscoelastic compliance and relaxation modulus measured using a microindentation technique, with data derived from standard macro measurements. Two nano/microindenters were used (Hysitron Triboscan and Nano XP Indenter) at two different laboratories. Four special time-dependent loading histories were applied: indentation under a step load, indentation under a constant load rate, indentation with a fixed depth of penetration and indentation under constant rate of penetration. The goal of the study is to assess the potential of this approach.

Minster, J.; Blahova, O.; Lukes, J.; Nemecek, J.

2010-08-01

159

Influence of thermal fluctuations on time characteristics of a single Josephson element with high damping. Exact solution  

NASA Astrophysics Data System (ADS)

The present paper presents an analysis of the influence of thermal fluctuations on the superconductive state life time and the turn-on delay time for a single Josephson element with high damping using the obtained exact representation of these time characteristics. The shape of the input pulse is assumed to be rectangular and the duration of the pulse is assumed to be much longer than the rum-on delay of the Josephson element. The analysis has been made within the well-known resistive model of a Josephson junction. It is shown that fluctuations may both decrease and increase the turn-on delay time. The results are presented in a form suitable for comparison with experiment.

Malakhov, A. N.; Pankratov, A. L.

1996-02-01

160

Multiscaling for systems with a broad continuum of characteristic lengths and times: Structural transitions in nanocomposites  

PubMed Central

The multiscale approach to N-body systems is generalized to address the broad continuum of long time and length scales associated with collective behaviors. A technique is developed based on the concept of an uncountable set of time variables and of order parameters (OPs) specifying major features of the system. We adopt this perspective as a natural extension of the commonly used discrete set of time scales and OPs which is practical when only a few, widely separated scales exist. The existence of a gap in the spectrum of time scales for such a system (under quasiequilibrium conditions) is used to introduce a continuous scaling and perform a multiscale analysis of the Liouville equation. A functional-differential Smoluchowski equation is derived for the stochastic dynamics of the continuum of Fourier component OPs. A continuum of spatially nonlocal Langevin equations for the OPs is also derived. The theory is demonstrated via the analysis of structural transitions in a composite material, as occurs for viral capsids and molecular circuits.

Pankavich, S.; Ortoleva, P.

2010-01-01

161

Evaluation of Timing Characteristics of Industrial Ethernet Networks Synchronized by means of IEEE 1588  

Microsoft Academic Search

This paper deals with time synchronization of distributed systems over Industrial Ethernet network. A new simulation model of IEEE1588 PTP is presented and discussed. The development platform used for simulation is OPNETtrade. Architecture of the proposed model is explained in details, highlighting some special features introduced by authors: modelization of drift and rate variations in the local oscillator and packet

A. Depari; P. Ferrari; A. Flammini; D. Marioli; A. Taroni

2007-01-01

162

Calculation of Synchronous Machine Constants Reactances and Time Constants Affecting Transient Characteristics  

Microsoft Academic Search

Recent advances in the theory of synchronous machines have introduced a large number of new constants. The method of symmetrical components requires sequence reactances, and an accurate theory of transients requires transient and subtransient reactances and time constants. Most of the published discussion on the constants has been concerned with the application, rather than the calculation of values. In this

L. A. Kilgore

1931-01-01

163

Space-Time Characteristics of Light Transmitted through Dense Clouds: A Green's Function Analysis  

Microsoft Academic Search

Here, previous work using photon diffusion theory to describe radiative transfer through dense plane-parallel clouds at nonabsorbing wavelengths is extended. The focus is on the scaling of space- and time-domain moments for transmitted light with respect to cloud thickness H and optical depth ; and the new results are as follows: accurate prefactors for asymptotic scaling, preasymptotic correction terms in

Anthony B. Davis; Alexander Marshak

2002-01-01

164

First-Time International and Domestic Freshmen: Enrollment Trends and Characteristics.  

ERIC Educational Resources Information Center

Selected comparisons of first-time international and domestic freshmen at the University of Southern California (USC) were undertaken, using data from the annual Higher Education General Information Survey (HEGIS) and the American Council on Education Freshman Survey. On-campus enrollment data for these two student groups are presented by sex for…

Overall, J. U.

165

Influence of Additives and Mixing Time on Crumb Grain Characteristics of Wheat Bread  

Microsoft Academic Search

Cereal Chem. 77(3):370-375 The effect of additives and processing parameters on wheat bread were investigated objectively using image analysis (IA). Five different bread types were produced by varying the ingredients (standard, standard with fat, standard with emulsifiers) and changing the mixing times (90, 150, and 240 sec). A digital IA system for wheat bread was developed from generic commercial software.

P. Crowley; H. Grau; E. K. Arendt

2000-01-01

166

Vehicle Characteristics of Fuel and Travel Time on Urban Arterials and Freeways.  

National Technical Information Service (NTIS)

The report describes the collection and analysis of travel time and fuel consumption data. These studies were made as part of an economic analysis to determine the benefits accuring from the construction of a freeway; benefits were determined on the freew...

R. B. Sawhill J. H. Matteson J. W. Hall

1970-01-01

167

Characteristics and fates of soluble microbial products in ceramic membrane bioreactor at various sludge retention times  

Microsoft Academic Search

The formation and fate of soluble microbial products (SMP) in membrane bioreactor (MBR) was investigated at various sludge retention times (SRT) for 170 days. The SMP concentration was estimated by feeding glucose, which could be completely degraded, and by measuring the dissolved organic carbon (DOC) of the effluent from MBR. Under the conditions of SRT of 20 days, influent DOC

Hang-Sik Shin; Seok-Tae Kang

2003-01-01

168

Temporal Characteristics of the Predictive Synchronous Firing Modeled by Spike-Timing-Dependent Plasticity  

ERIC Educational Resources Information Center

|When a sensory cue was repeatedly followed by a behavioral event with fixed delays, pairs of premotor and primary motor neurons showed significant increases of coincident spikes at times a monkey was expecting the event. These results provided evidence that neuronal firing synchrony has predictive power. To elucidate the underlying mechanism,…

Kitano, Katsunori; Fukai, Tomoki

2004-01-01

169

The Effect of Signal Characteristics on Reaction Time using Bisensory Stimulation  

Microsoft Academic Search

Sixty-four subjects were tested to examine the effect upon reaction time of the composition of bisensory signals simultaneously presented in two sensory modes. The stimulus display consisted of a flash of light from one of two lamps and a 1000 cps tone presented at one or other earphone of a binaurally balanced headset. Subjects responded by depressing push buttons. The

A. D. PERRIMENT

1969-01-01

170

Relationships Among Display Features, Eye Movement Characteristics, and Reaction Time in Visual Search  

Microsoft Academic Search

The relative contribution of number of fixations and fixation duration to reaction time in visual search was investigated. Ten participants (age 20--24 years) took part in each of two experiments. In Experiment 1, the experimental factors were display type (icon and file name), organization (arrangements with and without grouping), and number of stimuli presented (4, 8, and 16). In Experiment

Atsuo Murata; Nobuyasu Furukawa

2005-01-01

171

THE EFFECTS OF FAMILY CHARACTERISTICS AND TIME USE ON TEENAGE GIRLS’ AND BOYS’ HOUSEHOLD LABOR  

Microsoft Academic Search

Studies suggest that children’s housework contributions are minimal. However, much of this research focuses on young or early adolescent children and utilizes data regarding adult tasks, while ignoring chores children more often perform. We address these gaps by analyzing longitudinal time-use data collected from teens on the types of household chores that children are most likely to perform. Specifically, we

Constance T. Gager; Teresa M. Cooney; Kathleen Thiede Call

1998-01-01

172

Performance Characteristics of a Methodology to Quantify Adverse Events over Time in Hospitalized Patients  

PubMed Central

Objective To assess the performance characteristics of the Institute for Healthcare Improvement Global Trigger Tool (GTT) to determine its reliability for tracking local and national adverse event rates. Data Sources Primary data from 2008 chart reviews. Study Design A retrospective study in a stratified random sample of 10 North Carolina hospitals. Hospital-based (internal) and contract research organization–hired (external) reviewers used the GTT to identify adverse events in the same 10 randomly selected medical records per hospital in each quarter from January 2002 through December 2007. Data Collection/Extraction Interrater and intrarater reliability was assessed using ? statistics on 10 percent and 5 percent, respectively, of selected medical records. Additionally, experienced GTT users reviewed 10 percent of records to calculate internal and external teams' sensitivity and specificity. Principal Findings Eighty-eight to 98 percent of the targeted 2,400 medical records were reviewed. The reliability of the GTT to detect the presence, number, and severity of adverse events varied from ?=0.40 to 0.60. When compared with a team of experienced reviewers, the internal teams' sensitivity (49 percent) and specificity (94 percent) exceeded the external teams' (34 and 93 percent), as did their performance on all other metrics. Conclusions The high specificity, moderate sensitivity, and favorable interrater and intrarater reliability of the GTT make it appropriate for tracking local and national adverse event rates. The strong performance of hospital-based reviewers supports their use in future studies.

Sharek, Paul J; Parry, Gareth; Goldmann, Donald; Bones, Kate; Hackbarth, Andrew; Resar, Roger; Griffin, Frances A; Rhoda, Dale; Murphy, Cathy; Landrigan, Christopher P

2011-01-01

173

[Real-time UV imaging of chloramphenicol intrinsic dissolution characteristics from ophthalmic in situ gel].  

PubMed

In this paper, chloramphenicol was selected as a model drug to prepare in situ gels. The intrinsic dissolution rate of chloramphenicol from in situ gel was evaluated using the surface dissolution imaging system. The results indicated that intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel decreased significantly when the poloxamer concentration increased. The addition of the thickener reduced the intrinsic dissolution rate of chloramphenicol thermosensitive gel, wherein carbomer had the most impact. Different dilution ratios of simulated tear fluid greatly affected gel temperature, and had little influence on the intrinsic dissolution rate of chloramphenicol from the thermosensitive in situ gel. The pH of simulated tear fluid had little influence on the intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel. For the pH sensitive in situ gel, the dissolution rates of chloramphenicol in weak acidic and neutral simulated tear fluids were slower than that in weak alkaline simulated tear fluid. In conclusion, the intrinsic dissolution of chloramphenicol from in situ gel was dependent on formulation and physiological factors. With advantages of small volume sample required and rapid detection, the UV imaging method can be an efficient tool for the evaluation of drug release characteristics of ophthalmic in situ gel. PMID:24133985

Chen, Jian-Xiu; Guo, Zhen; Li, Hai-Yan; Wu, Li; He, Zhong-Gui; Hu, Rong-Feng; Zhang, Ji-Wen

2013-07-01

174

Timing and extent of tissue removal affect reproduction characteristics of an invasive species Heracleum mantegazzianum  

Microsoft Academic Search

Response of the invasive species Heracleum mantegazzianum to experimental removal of tissues was studied in the Czech Republic. The study aimed at determining (i) how efficiently\\u000a plants respond, in terms of quantity and quality of produced fruit, to the removal of different amounts of generative and\\/or\\u000a vegetative tissues; and (ii) whether regeneration ability depends on the time of treatment. Total number

Petr Pyšek; LukᚠKrinke; Vojt?ch Jarošík; Irena Perglová; Jan Pergl; Lenka Moravcová

2007-01-01

175

Space-time implosion characteristics of laser-irradiated fusion targets  

Microsoft Academic Search

An x-ray pinhole camera is coupled to an x-ray streak camera for detailed measurements of the implosion of laser fusion targets. Simultaneous spatial and temporal resolutions of 6 ..mu..m and 15 psec are attained. Resultant R and t implosion diagrams show time-dependent implosion velocities in the range of (3--4) x 10⁷ cm\\/sec.

D. T. Attwood; L. W. Coleman; M. J. Boyle; J. T. Larsen; D. W. Phillion; K. R. Manes

1977-01-01

176

Analytical Description of Signal Characteristics and Interference For Time Hopped UWB System  

Microsoft Academic Search

In this paper, signal and interference characterisation of Time Hopped Ultra Wideband (TH-UWB) systems is considered. Some special problems often neglected in theoretical studies are discussed, such as the bound between neareld and fareld and the distortions of wave shape. The transmitted TH-UWB signal is shown to be a cyclostationary process, as is the interference caused by TH-UWB signal on

Jian Zhang; Rodney A. Kennedy; Thushara D. Abhayapala

2002-01-01

177

Temporal propagation characteristics of ultrashort space- time Gaussian pulses in a laser satellite communication system  

Microsoft Academic Search

Tractable analytic expressions are obtained for the temporal broadening and scintillations of a narrowband, space-time Gaussian pulse propagating through clear-air weak atmospheric turbulence in a laser satellite communication system. The temporal broadening is deduced from the 1\\/e2 point of the temporal mean intensity and calculation of the temporal scintillations involves the second moment of intensity. Integral representations for the first

Deborah Eliza Tjin Tham Sjin Kelly

1998-01-01

178

Limits and characteristics of the multifractal behaviour of a high-resolution rainfall time series  

Microsoft Academic Search

The multifractal properties of a 2-year time series of 8-min rainfall intensity observations are investigated. The empirical probability distribution function suggests a hyperbolic intermittency with divergence of moment of order greater than 2. The power spectrum E(f) of the series obeys a power law form E(f)=f -0.66 in the range of scales 8 min to approximately 3 days. The variation

J. Olsson

1995-01-01

179

Analog memory and spike-timing-dependent plasticity characteristics of a nanoscale titanium oxide bilayer resistive switching device  

NASA Astrophysics Data System (ADS)

We demonstrated analog memory, synaptic plasticity, and a spike-timing-dependent plasticity (STDP) function with a nanoscale titanium oxide bilayer resistive switching device with a simple fabrication process and good yield uniformity. We confirmed the multilevel conductance and analog memory characteristics as well as the uniformity and separated states for the accuracy of conductance change. Finally, STDP and a biological triple model were analyzed to demonstrate the potential of titanium oxide bilayer resistive switching device as synapses in neuromorphic devices. By developing a simple resistive switching device that can emulate a synaptic function, the unique characteristics of synapses in the brain, e.g. combined memory and computing in one synapse and adaptation to the outside environment, were successfully demonstrated in a solid state device.

Seo, Kyungah; Kim, Insung; Jung, Seungjae; Jo, Minseok; Park, Sangsu; Park, Jubong; Shin, Jungho; Biju, Kuyyadi P.; Kong, Jaemin; Lee, Kwanghee; Lee, Byounghun; Hwang, Hyunsang

2011-06-01

180

Timing of Malaria Infection during Pregnancy Has Characteristic Maternal, Infant and Placental Outcomes.  

PubMed

We conducted a clinical study of pregnant women in Blantyre, Malawi to determine the effect of the timing of malaria infection during pregnancy on maternal, infant and placental outcomes. Women were enrolled in their first or second trimester of their first or second pregnancy and followed every four weeks until delivery. Three doses of sulfadoxine-pyrimethamine were given for intermittent preventive treatment for malaria, and all episodes of parasitemia were treated according to the national guidelines. Placentas were collected at delivery and examined for malaria parasites and pigment by histology. Pregnant women had 0.6 episodes of malaria per person year of follow up. Almost all episodes of malaria were detected at enrollment and malaria infection during the follow up period was rare. Malaria and anemia at the first antenatal visit were independently associated with an increased risk of placental malaria detected at delivery. When all episodes of malaria were treated with effective antimalarial medication, only peripheral malaria infection at the time of delivery was associated with adverse maternal and infant outcomes. One quarter of the analyzed placentas had evidence of malaria infection. Placental histology was 78% sensitive and 89% specific for peripheral malaria infection during pregnancy. This study suggests that in this setting of high antifolate drug resistance, three doses of sulfadoxine-pyrimethamine maintain some efficacy in suppressing microscopically detectable parasitemia, although placental infection remains frequent. Even in this urban setting, a large proportion of women have malaria infection at the time of their first antenatal care visit. Interventions to control malaria early and aggressive case detection are required to limit the detrimental effects of pregnancy-associated malaria. PMID:24058614

Kalilani-Phiri, Linda; Thesing, Phillip C; Nyirenda, Osward M; Mawindo, Patricia; Madanitsa, Mwayi; Membe, Gladys; Wylie, Blair; Masonbrink, Abbey; Makwakwa, Kingsley; Kamiza, Steve; Muehlenbachs, Atis; Taylor, Terrie E; Laufer, Miriam K

2013-09-18

181

Timing of Malaria Infection during Pregnancy Has Characteristic Maternal, Infant and Placental Outcomes  

PubMed Central

We conducted a clinical study of pregnant women in Blantyre, Malawi to determine the effect of the timing of malaria infection during pregnancy on maternal, infant and placental outcomes. Women were enrolled in their first or second trimester of their first or second pregnancy and followed every four weeks until delivery. Three doses of sulfadoxine-pyrimethamine were given for intermittent preventive treatment for malaria, and all episodes of parasitemia were treated according to the national guidelines. Placentas were collected at delivery and examined for malaria parasites and pigment by histology. Pregnant women had 0.6 episodes of malaria per person year of follow up. Almost all episodes of malaria were detected at enrollment and malaria infection during the follow up period was rare. Malaria and anemia at the first antenatal visit were independently associated with an increased risk of placental malaria detected at delivery. When all episodes of malaria were treated with effective antimalarial medication, only peripheral malaria infection at the time of delivery was associated with adverse maternal and infant outcomes. One quarter of the analyzed placentas had evidence of malaria infection. Placental histology was 78% sensitive and 89% specific for peripheral malaria infection during pregnancy. This study suggests that in this setting of high antifolate drug resistance, three doses of sulfadoxine-pyrimethamine maintain some efficacy in suppressing microscopically detectable parasitemia, although placental infection remains frequent. Even in this urban setting, a large proportion of women have malaria infection at the time of their first antenatal care visit. Interventions to control malaria early and aggressive case detection are required to limit the detrimental effects of pregnancy-associated malaria.

Kalilani-Phiri, Linda; Thesing, Phillip C.; Nyirenda, Osward M.; Mawindo, Patricia; Madanitsa, Mwayi; Membe, Gladys; Wylie, Blair; Masonbrink, Abbey; Makwakwa, Kingsley; Kamiza, Steve; Muehlenbachs, Atis; Taylor, Terrie E.; Laufer, Miriam K.

2013-01-01

182

An event based real-time conditioned predictor of hourly hyetograph characteristics  

NASA Astrophysics Data System (ADS)

Setting up stochastic models capable to perform real-time conditioned rainfall predictions at high temporal resolution is crucial in developing hydro-geological early warning systems. Indeed, several rainfall-induced dangerous phenomena taking place at catchment or slope scale, such as flash floods and debris flows, may be triggered by relatively short rainfall events. The small spatial resolution at which the predictions are needed does not allow to make use neither of rainfall forecasts based on global circulation models, nor of data coming from radar sensors. Thus, the most reliable source of information is still represented by rain gauges installed at the site to be monitored. Modelling of point rainfall series has been addressed in hydrological literature with two major approaches: cluster-based models and event-based models. In this paper, using rainfall data observed in real time during a storm, a stochastic predictor of its future evolution is presented. The core of the predictor consists in an event based stochastic model. An event based approach is adopted, since it permits to identify a storm on the basis of the observed series of rainfall data and to calculate univocally its probability, thus allowing to perform the desired predictions in a relatively straightforward way. With this approach, predictions can be conditioned only to the part of real time observed rainfall data on which future evolution of the storm depends, in the stochastic sense. Conversely, cluster-based stochastic models, widely used for the generation of synthetic rainfall series, are not trivially suitable for real-time conditioned predictions, since they do not allow to evaluate unambiguously the probability of an observed hyetograph, because it can be generated by more than one combination of rain cells. The proposed model has been calibrated with hourly rainfall series of the rain gauges of the meteorological alert network of the Civil Protection Agency of Campania, Southern Italy. The statistical hypotheses on which the model is based have been checked by classical statistical tests, such as Blum-Kiefer-Rosenblatt test for independence. Furthermore, the information about the observed internal structure of the storm, at hourly scale, has been coupled with the external structure model, allowing to perform conditioned predictions of hydrologic response indexes, depending on the future evolution of hyetograph shape.

Giorgio, Massimiliano; Greco, Roberto

2010-05-01

183

Seeing time-reversal transmission characteristics through kinetic anti-ferromagnetic Ising chain  

NASA Astrophysics Data System (ADS)

As an example of our new approach to complex near-field (NF) scattering of electromagnetic waves, the time-reversal (TR) transmission process on an NF current-element array is mapped to the statistical process on a kinetic Ising transmission chain. Equilibrium statistical mechanics and non-equilibrium Monte Carlo (MC) dynamics help us to find signal jamming, aging, annihilating, creating, and TR symmetry breaking on the chain with inevitable background noises; and these results are general in NF systems where complex electromagnetic scattering arises.

Chen, Ying-Ming; Wang, Bing-Zhong

2012-02-01

184

Characteristics of chiral and racemic ketoprofen drugs using terahertz time-domain spectroscopy  

NASA Astrophysics Data System (ADS)

Absorption spectra of chiral S-(+)- and racemic RS-ketoprofen pharmaceutical molecules in crystalline form were recorded in the terahertz region between 6 and 66 cm-1 (0.2 ~ 2.0 THz) by using time-domain terahertz spectroscopic (THz-TDS) measurement. Different distinctive absorption features were observed which are strikingly sensitive to the change of subtle conformational structures within such isostructural crystal molecules. The results suggest that the THz-TDS technique can be definitely used for distinguishing between chiral and racemic compounds in pharmaceutical and biological fields.

Du, Yong; Liu, Jianjun; Hong, Zhi

2013-08-01

185

Aerodynamics of cyclist posture, bicycle and helmet characteristics in time trial stage.  

PubMed

The present work is focused on the aerodynamic study of different parameters, including both the posture of a cyclist's upper limbs and the saddle position, in time trial (TT) stages. The aerodynamic influence of a TT helmet large visor is also quantified as a function of the helmet inclination. Experiments conducted in a wind tunnel on nine professional cyclists provided drag force and frontal area measurements to determine the drag force coefficient. Data statistical analysis clearly shows that the hands positioning on shifters and the elbows joined together are significantly reducing the cyclist drag force. Concerning the saddle position, the drag force is shown to be significantly increased (about 3%) when the saddle is raised. The usual helmet inclination appears to be the inclination value minimizing the drag force. Moreover, the addition of a large visor on the helmet is shown to provide a drag coefficient reduction as a function of the helmet inclination. Present results indicate that variations in the TT cyclist posture, the saddle position and the helmet visor can produce a significant gain in time (up to 2.2%) during stages. PMID:22084053

Chabroux, Vincent; Barelle, Caroline; Favier, Daniel

2011-11-11

186

Operational characteristics of energy storage high temperature superconducting flywheels considering time dependent processes  

NASA Astrophysics Data System (ADS)

Technical and economical feasibilities of short-term energy storage flywheels with high temperature superconducting (HTS) bearing are widely investigated. It is essential to reduce the ac losses caused by magnetic field variations in HTS bulk disks/rings (levitators) used in the magnetic bearings of flywheels. For the HTS bearings the calculation and measurement of the magnetic field distribution were performed. Effects like eccentricity, tilting were measured. Time dependency of the levitation force following a jumpwise movement of the permanent magnet was measured. The results were used to setup an engineering design algorithm for energy storage HTS flywheels. This algorithm was applied to an experimental HTS flywheel model with a disk type permanent magnet motor/generator unit designed and constructed by the authors. A conceptual design of the disk-type motor/generator with radial flux is shown.

Vajda, Istvan; Kohari, Zalan; Porjesz, Tamas; Benko, Laszlo; Meerovich, V.; Sokolovsky; Gawalek, W.

2002-08-01

187

SPACE-TIME CHARACTERISTICS OF DIURNAL RAINFALL VARIATION IN MATSUYAMA PLAIN  

NASA Astrophysics Data System (ADS)

We investigated the diurnal rainfall variation in Matsuyama plain using datasets from AMeDAS, MLIT, and local government. The evening maximum precipitation is especially remarkable in the inland region and along a river. It is known that a river is street of wind for land and sea breezes. Sea breeze would contribute to an increase in the water vapor content over inland regions through the moist air advection from coastal regions. During the period of 1980-2009, the time when the morning maximum precipitation appears shift two hours later every ten years. Similarly, the offshore land breeze is getting more significant at the rate of 200 ms-1h every ten years.

Fujimoto, Masato; Watanabe, Keiko; Moriwaki, Ryo

188

Conformational characteristics of chiral and racemic naproxen molecules investigated by terahertz time-domain spectroscopy  

NASA Astrophysics Data System (ADS)

Absorption spectra in the terahertz region between 6 and 66 cm-1 (0.2 ~ 2.0 THz) were measured for S-(+)-, R-(-) and RS-naproxen pharmaceutical molecules in crystalline form using time-domain terahertz spectroscopic (THz-TDS) technique at room temperature. Different absorption features were observed for the racemic RS-naproxen and its corresponding enantiomers (S-(+)- and R-(-)-naproxen). The observed THz absorption bands are strikingly sensitive to the change of subtle conformational structures despite that the isostructurality exists within such crystal molecules. The results show that the THz-TDS technique can be definitely used for distinguishing between chiral and racemic compounds in pharmaceutical and biological fields.

Du, Yong; Zhao, Rongjiao; Hao, Guohui; Guo, Changsheng; Hong, Zhi

2011-11-01

189

Signal characteristics in coordinate time series of GPS-DORIS co-located stations  

NASA Astrophysics Data System (ADS)

Weekly time series of coordinate residuals are analysed using the wavelet transform in order to investigate the signal of the nonlinear station motion of 14 GPS-DORIS (Global Positioning System-Doppler Orbitography and Radiopositioning Integrated by Satellite) co-located stations over 2006.0 - 2011.8. The data used were computed by IGN/JPL (Institut Géographique National, France/ Jet Propulsion Laboratory, USA) using the GIPSY-OASIS II software package, referred to ITRF2005 and expressed in the local geodetic reference frame. The Multi-resolution analysis has assessed well the nonlinear trends and the seasonal signals in the studied time series. The horizontal displacements (North and East) of the stations are mainly associated to the plate tectonics and the vertical displacements are associated to the local subsidence or postglacial rebound. However, the error due to the period of 118 days was not hopefully removed in the ign09wd01 solution for the totality of DORIS stations. Using the VisuShrink method with soft thresholding, the obtained results show that the DORIS positions are more distorted than those of GPS. Indeed, the standard deviation of the noise in respectively North, East and Vertical components is in the range of 1-2, 0.5-1 and 2-4 mm for GPS and 6-11, 5-17 and 6-15 mm for DORIS. For DORIS positions, the noise level in the East component is more important compared to the North and the Vertical ones and it is small in the stations at high latitude relatively to the other ones. Keywords: DORIS; GPS; Station coordinates; Wavelets; Multi-resolution analysis; De-noising.

Khelifa, S.; Kahlouche, S.; Faouzi Belbachir, M.

2012-04-01

190

Timing and characteristics of Paleozoic deformation and metamorphism in the Alabama Inner Piedmont  

SciTech Connect

The Opelika Complex in the Inner Piedmont of Alabama and Georgia records multiple periods of Paleozoic deformation and metamorphism. Rb-Sr isochron ages and thermobarometric data are reported for pelitic schists and spatially associated metagranite. A whole-rock Rb-Sr isochron age of 369 {plus minus} 5 Ma for Farmville Metagranite is interpreted as the time of syntectonic emplacement and crystallization within Auburn Gneiss and Loachapoka Schist of the Opelika Complex. Metapelitic units from the Auburn Gneiss and Loachapoka Schist exhibit a dominant S{sub 1} foliation which is continuous into Farmville Metagranite. Metamorphic assemblages defining this foliation (garnet + biotite + plagioclase + quartz + muscovite {plus minus} kyanite {plus minus} staurolite) indicate middle- to upper-amphibolite-facies conditions. Garnet-biotite geothermometry yields temperature estimates for final equilibration of 541{degree} to 580{degree}C, and garnet-plagioclase-kyanite-quartz and/or garnet-plagioclase-biotite-muscovite geobarometry indicate pressures of 6.8 to 8.2 kb for the matrix assemblage. This schistosity is retrograded by a S{sub 2} crenulation cleavage exhibiting greenschist-facies assemblages. The S{sub 2} cleavage in the Opelika Complex represents a late-stage (D{sub 2}) deformational event showing similar fabric and kinematic relationships to spatially associated mylonites from the Towaliga fault. Two feldspar thermometry from an extensional shear band in Farmville Metagranite yields temperatures of 302{degree} to 406{degree}C. A Rb-Sr mineral isochron from a strongly foliated sample of Farmville Metagranite yields an age of 296 {plus minus} 4 Ma. This age is interpreted as the time of Sr isotopic reequilibration, apparently in response to a period of uplift or thrusting associated with the Alleghanian orogeny.

Goldberg, S.A. (Univ. of North Carolina, Chapel Hill (USA)); Steltenpohl, M.G. (Auburn Univ., AL (USA))

1990-12-01

191

Optical Characteristics of the Phototroph Thiocapsa roseopersicina and Implications for Real-Time Monitoring of the Bacteriochlorophyll Concentration  

PubMed Central

Optical characteristics of a Thiocapsa roseopersicina culture and environmental samples containing T. roseopersicina were investigated in the spectral range of 400 to 1,100 nm (absorption coefficient, diffuse attenuation coefficient, and reflectance). Specific absorption coefficients of T. roseopersicina at wavelengths of 480, 520, 550, 580, 805, 860, and 880 nm were determined. It is suggested that the optical properties of T. roseopersicina in the near-infrared range of 800 to 930 nm, confirmed in this study, may be used for development of remote sensing techniques for real-time monitoring of T. roseopersicina and other bacteriochlorophyll a-containing microbes.

Gitelson, A.; Stark, R.; Dor, I.; Michelson, O.; Yacobi, Y. Z.

1999-01-01

192

Optical characteristics of the phototroph Thiocapsa roseopersicina and implications for real-time monitoring of the bacteriochlorophyll concentration.  

PubMed

Optical characteristics of a Thiocapsa roseopersicina culture and environmental samples containing T. roseopersicina were investigated in the spectral range of 400 to 1,100 nm (absorption coefficient, diffuse attenuation coefficient, and reflectance). Specific absorption coefficients of T. roseopersicina at wavelengths of 480, 520, 550, 580, 805, 860, and 880 nm were determined. It is suggested that the optical properties of T. roseopersicina in the near-infrared range of 800 to 930 nm, confirmed in this study, may be used for development of remote sensing techniques for real-time monitoring of T. roseopersicina and other bacteriochlorophyll a-containing microbes. PMID:10427024

Gitelson, A; Stark, R; Dor, I; Michelson, O; Yacobi, Y Z

1999-08-01

193

[Chemical characteristic of water-soluble ions in total suspended particles (TSP) at Lijiang winter time].  

PubMed

25 total suspended particles (TSP) samples were collected at Lijiang city from Dec 2008 to Jan 2009. Analyzed results indicated that the concentration of CU-, NO3-, SO4(2-), Na+ , NH+, K+, Mg2+ and Ca2+ were 16.00, 14.95, 49.40, 3.12, 44.75, 8.65, 29.50 and 183.02 neq x m(-3) respectively. The average total aerosol loading was 349.39 neq x m(-3), and the average concentration of Ca2+ was 52.38% percent of average total concentration, indicated it was the dominant ion in this sampling. The average concentration of detected cations was 3.35 times of anions, suggested the sum of cations generally exceed the sum of anions in our samples, and the main anion was not detected. The average value of SO4(2-)/NO3- was 3.98, showing that the sustained sources have mainly influences on air. According to the correlation coefficients among ions and factor analysis, Ca2+ and Mg2+ in our samples were from dust, and the sources of NO3-, SO4(2-), NH4+ and K+ were related to various combustion processes by human activities. As a whole, the ions in our samples were mainly combined as CaCO3, (NH4)2SO4, MgCO3, KNO3 and a little CaSO4 and Ca(NO3)2. PMID:21634155

Zhang, Ning-Ning; He, Yuan-Qing; Wang, Chun-Feng; He, Xian-Zhong; Xin, Hui-Juan

2011-03-01

194

Timing and characteristics of the latest mare eruption on the Moon  

NASA Astrophysics Data System (ADS)

Unraveling the timing and duration of mare volcanism on the Moon is essential for understanding its thermal evolution. The end of mare volcanism is poorly constrained, because mare basalts are incompletely sampled. In this study, employing SELENE (Kaguya) high-resolution images, we performed new crater size-frequency measurements for 49 young mare units (<~3.0 Ga) in the Procellarum KREEP Terrane (PKT), in which the latest magma eruption of the Moon occurred. Mare volcanism in this region continued until ~ 1.5 Ga, suggesting that volcanic activity in this region ceased ~ 1.0 Ga after the magma eruption had globally ceased 2.5-3.0 Ga. Volcanic activity may have peaked 1.8-2.2 Ga ago. The youngest basalts occur around the Aristarchus plateau and the Kepler crater, which are located in the central region of the PKT. It is likely that heating in the crust due to the concentration of heat-producing elements in the PKT delayed cooling of a partial-melting zone in the underlying mantle. In contrast with previous basalt dating in this region, our results indicate a higher correlation between ages and spectral types of mare basalts; the young mare units in the PKT tend to have spectral types corresponding to high titanium contents, while low titanium basalts occur mainly in the early stage. The titanium variation in mare basalts may reflect vertical heterogeneity in TiO 2 content in the upper mantle beneath the PKT.

Morota, Tomokatsu; Haruyama, Junichi; Ohtake, Makiko; Matsunaga, Tsuneo; Honda, Chikatoshi; Yokota, Yasuhiro; Kimura, Jun; Ogawa, Yoshiko; Hirata, Naru; Demura, Hirohide; Iwasaki, Akira; Sugihara, Takamitsu; Saiki, Kazuto; Nakamura, Ryosuke; Kobayashi, Shingo; Ishihara, Yoshiaki; Takeda, Hiroshi; Hiesinger, Harald

2011-02-01

195

Acute and repair stage characteristics of magnetic resonance relaxation times in oxygen-induced pulmonary edema.  

PubMed

Proton magnetic relaxation times, T1 and T2, were determined for rat lungs exposed to 80% oxygen for a duration of 2 weeks. The transverse magnetization decay curve of the lung tissue was multiexponential. A linear combination of two decay curves with different T2 values fits the multiexponential decay suggesting that there are at least two different components of tissue water in the lung. Remarkable prolongation of T1 and T2 was demonstrated as lung injuries progressed in the acute stage of pulmonary edema. Both 1/T1 and 1/T2 were significantly correlated with 1/water content of the lung tissue. In the repair stage, T1 and T2 were significantly shortened. Shortening coincided with the spontaneous resolution of pulmonary edema. Relaxation rates showed no significant correlation with 1/water content in this stage. These results indicate that the physical state of water in the tissue is affected not only by the water content but also by the derangement of macromolecules in pulmonary edema. T2 was more sensitive than T1 for detecting pulmonary damage. PMID:3231071

Shioya, S; Haida, M; Tsuji, C; Ohta, Y; Yamabayashi, H; Fukuzaki, M; Kimula, Y

1988-12-01

196

The cuffless arterial blood pressure estimation based on the timing- characteristics of second heart sound.  

PubMed

Continuous and non-invasive monitoring of blood pressure (BP) is important to prevent hypertensive patients from stroke and heart attack. However, most of the prevalent BP devices can provide solely intermittent measurements. In this study, a novel parameter RS2, defined as the time interval from the R wave of electrocardiographic (ECG) signal to the peak of second heart sound of phonocardiographic (PCG) signal, was used for BP estimation. Experiment was conducted on 66 normal and 19 abnormal subjects during resting condition. The results of this study showed that estimation error of systolic BP (SBP) and diastolic BP (DBP) was 2.0+/-7.5 mmHg and 0.9+/-5.1 mmHg respectively. 94.7% of the difference between measured and estimated SBPs was within +/-2 standard deviations in the Bland Altman plot. 93.4% of the difference between measured and estimated DBFs was within +/-2 standard deviations in the Bland Altman plot. The preliminary results illustrated that the RS2 is a promising parameter for continuous and non-invasive estimation of BP in homecare and mobile healthcare. PMID:17946894

Wong, M Y M; Zhang, X Y; Zhang, Y T

2006-01-01

197

Effect of storage time and temperature on the physicochemical and sensory characteristics of commercial apricot jam.  

PubMed

Storage conditions are important factors for jam quality. The objective of this study was to monitor the physicochemical stability and sensorial profile of apricot jam during storage for 60days at 5°C, 25°C and 37°C. For that purpose, special attention was paid to total soluble solids (TSS), titratable acidity (TA), colour, free amino acids (FAA), total sugars (TS) and hydroxymethylfurfural (HMF). The decreasing parameter for jam at the end of storage under 5°C, 25°C and 37°C, respectively, were 16.81%, 34.30% and 56.01% for FAA, and 5.52%, 9.02% and 7.46% for TS; likewise, the increasing were 19.81%, 22.94% and 25.07% for TA, 3.15%, 4.08% and 4.47% for TSS, 15.96%, 112.76% and 150% for HMF. Jam stability was better at 5°C than 25°C and 37°C. The interaction time-temperature factor had significant effects on pH, TS, FAA and HMF, unlike TA, TSS and sensorial profile. PMID:24128444

Touati, Noureddine; Tarazona-Díaz, Martha Patricia; Aguayo, Encarna; Louaileche, Hayette

2013-08-16

198

Oil Sands Characteristics and Time-Lapse and P-SV Seismic Steam Monitoring, Athabasca, Canada  

NASA Astrophysics Data System (ADS)

A vast amount of oil sands exists in the Athabasca area, Alberta, Canada. These oil sands consist of bitumen (extra-heavy oil) and unconsolidated sand distributed from surface to a depth of 750 meters. Including conventional crude oil, the total number of proved remaining oil reserves in Canada ranks second place in the world after Saudi Arabia. For the production of bitumen from the reservoir 200 to 500 meters in depth, the Steam Assisted Gravity Drainage (SAGD) method (Steam Injection EOR) has been adopted as bitumen is not movable at original temperatures. It is essential to understand the detailed reservoir distribution and steam chamber development extent for optimizing the field development. Oil sands reservoir characterization is conducted using 3D seismic data acquired in February 2002. Conducting acoustic impedance inversion to improve resolution and subsequent multi-attribute analysis integrating seismic data with well data facilitates an understanding of the detailed reservoir distribution. These analyses enable the basement shale to be imaged, and enables identification to a certain degree of thin shale within the reservoir. Top and bottom depths of the reservoir are estimated in the range of 2.0 meters near the existing wells even in such a complex channel sands environment characterized by abrupt lateral sedimentary facies changes. In March 2006, monitoring 3D seismic data was acquired to delineate steam-affected areas. The 2002 baseline data is used as a reference data and the 2006 monitoring data is calibrated to the 2002 seismic data. Apparent differences in the two 3D seismic data sets with the exception of production related response changes are removed during the calibration process. P-wave and S-wave velocities of oil sands core samples are also measured with various pressures and temperatures, and the laboratory measurement results are then combined to construct a rock physics model used to predict velocity changes induced by steam-injection. The differences of the seismic responses between the time-lapse seismic volumes can be quantitatively explained by P-wave velocity decrease of the oil sands layers due to steam-injection. In addition, the data suggests that a larger area would be influenced by pressure than temperature. We calculate several seismic attributes such as RMS values of amplitude difference, maximum cross correlations, and interval velocity differences. These attributes are integrated by using self-organization maps (SOM) and K-means methods. By this analysis, we are able to distinguish areas of steam chamber growth from transitional and non-affected areas. In addition, 3D P-SV converted-wave processing and analysis are applied on the second 3D data set (recorded with three-component digital sensor). Low Vp/Vs values in the P-SV volume show areas of steam chamber development, and high Vp/Vs values indicate transitional zones. Our analysis of both time-lapse 3D seismic and 3D P-SV data along with the rock physics model can be used to monitor qualitatively and quantitatively the rock property changes of the inter-well reservoir sands in the field.

Takahashi, A.; Nakayama, T.; Kashihara, K.; Skinner, L.; Kato, A.

2008-12-01

199

Using horizontal transport characteristics to infer an emission height time series of volcanic SO2  

NASA Astrophysics Data System (ADS)

Characterizing the emission height of sulfur dioxide (SO2) from volcanic eruptions yields information about the strength of volcanic activity, and is crucial for the assessment of possible climate impacts and validation of satellite retrievals of SO2. Sensors such as the Ozone Monitoring Instrument (OMI) on the polar-orbiting Aura satellite provide accurate maps of the spatial distribution of volcanic SO2, but provide limited information on its vertical distribution. The goal of this work is to explore the possible use of a trajectory model in reconstructing both the temporal activity and injection altitude of volcanic SO2 from OMI column measurements observed far from the volcano. Using observations from the November 2006 eruption of Nyamuragira, back trajectories are run and statistical analyses are computed based on the distance of closest approach to the volcano. These statistical analyses provide information about the emission height time series of SO2 injection from that eruption. It is found that the eruption begins first injecting SO2 into the upper troposphere, between 13 km and 17 km, on November 28th 2006. This is then followed by a slow decay in injection altitude, down to 6 km, over subsequent days. The emission height profile is used to generate an optimal reconstruction based on forward trajectories and compared to OMI SO2 observations. The inferred altitude of the Nyamuragira SO2cloud is also compared to the altitude of sulfate aerosols detected in aerosol backscatter vertical profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO).

Hughes, E. J.; Sparling, L. C.; Carn, S. A.; Krueger, A. J.

2012-09-01

200

The Influence of Pretreatment Characteristics and Radiotherapy Parameters on Time Interval to Development of Radiation-Associated Meningioma  

SciTech Connect

Purpose: To identify pretreatment characteristics and radiotherapy parameters which may influence time interval to development of radiation-associated meningioma (RAM). Methods and Materials: A Medline/PUBMED search of articles dealing with RAM yielded 66 studies between 1981 and 2006. Factors analyzed included patient age and gender, type of initial tumor treated, radiotherapy (RT) dose and volume, and time interval from RT to development of RAM. Results: A total of 143 patients with a median age at RT of 12 years form the basis of this report. The most common initial tumors or conditions treated with RT were medulloblastoma (n = 27), pituitary adenoma (n = 20), acute lymphoblastic leukemia (n = 20), low-grade astrocytoma (n = 19), and tinea capitis (n = 14). In the 116 patients whose RT fields were known, 55 (47.4%) had a portion of the brain treated, whereas 32 (27.6%) and 29 (25.0%) had craniospinal and whole-brain fields. The median time from RT to develop a RAM or latent time (LT) was 19 years (range, 1-63 years). Male gender (p = 0.001), initial diagnosis of leukemia (p = 0.001), and use of whole brain or craniospinal field (p <= 0.0001) were associated with a shorter LT, whereas patients who received lower doses of RT had a longer LT (p < 0.0001). Conclusions: The latent time to develop a RAM was related to gender, initial tumor type, radiotherapy volume, and radiotherapy dose.

Paulino, Arnold C., E-mail: apaulino@tmhs.or [Department of Radiology, Section of Radiation Oncology, Baylor College of Medicine, Houston, TX (United States); Ahmed, Irfan M.; Mai, Wei Y.; Teh, Bin S. [Department of Radiology, Section of Radiation Oncology, Baylor College of Medicine, Houston, TX (United States)

2009-12-01

201

Digestibility, fecal characteristics, and plasma glucose and urea in dogs fed a commercial dog food once or three times daily.  

PubMed

Digestibility, fecal characteristics, and levels of glucose and urea in the plasma were determined in 8 dogs that received 2 different dog foods once or 3 times daily. One dog food (A) was 5 times more expensive than the other (B). Fecal pH and consistency, digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and crude fiber (CF) were determined. Blood samples were taken from 30 min before to 60 min after a meal. Digestibilities of DM, OM, and CP, and fecal consistency were higher, and daily fecal excretion and fecal pH were lower when dogs were fed food A (P < 0.001). The feeding schedule had no effect on plasma glucose and urea. Neither feeding X frequency nor food 3 frequency interactions was significant for the parameters studied. PMID:20440906

Brambillasca, Sebastián; Purtscher, Frederick; Britos, Alejandro; Repetto, José L; Cajarville, Cecilia

2010-02-01

202

Investigating the spectral characteristics of backscattering from heterogeneous spherical nuclei using broadband finite-difference time-domain simulations  

NASA Astrophysics Data System (ADS)

Reflectance spectra measured from epithelial tissue have been used to extract size distribution and refractive index of cell nuclei for noninvasive detection of precancerous changes. Despite many in vitro and in vivo experimental results, the underlying mechanism of sizing nuclei based on modeling nuclei as homogeneous spheres and fitting the measured data with Mie theory has not been fully explored. We describe the implementation of a three-dimensional finite-difference time-domain (FDTD) simulation tool using a Gaussian pulse as the light source to investigate the wavelength-dependent characteristics of backscattered light from a nuclear model consisting of a nucleolus and clumps of chromatin embedded in homogeneous nucleoplasm. The results show that small-sized heterogeneities within the nuclei generate about five times higher backscattering than homogeneous spheres. More interestingly, backscattering spectra from heterogeneous spherical nuclei show periodic oscillations similar to those from homogeneous spheres, leading to high accuracy of estimating the nuclear diameter by comparison with Mie theory. In addition to the application in light scattering spectroscopy, the reported FDTD method could be adapted to study the relations between measured spectral data and nuclear structures in other optical imaging and spectroscopic techniques for in vivo diagnosis.

Chao, Guo-Shan; Sung, Kung-Bin

2010-01-01

203

Effect of self-consistent electric field on characteristics of graphene p-i-n tunneling transit-time diodes  

NASA Astrophysics Data System (ADS)

We develop a device model for p-i-n tunneling transit-time diodes based on single- and multiple graphene layer structures operating at the reverse bias voltages. The model of the graphene tunneling transit-time diode (GTUNNETT) accounts for the features of the interband tunneling generation of electrons and holes and their ballistic transport in the device i-section, as well as the effect of the self-consistent electric field associated with the charges of propagating electrons and holes. Using the developed model, we calculate the dc current-voltage characteristics and the small-signal ac frequency-dependent admittance as functions of the GTUNNETT structural parameters, in particular, the number of graphene layers and the dielectric constant of the surrounding media. It is shown that the admittance real part can be negative in a certain frequency range. As revealed, if the i-section somewhat shorter than one micrometer, this range corresponds to the terahertz frequencies. Due to the effect of the self-consistent electric field, the behavior of the GTUNNETT admittance in the range of its negativity of its real part is rather sensitive to the relation between the number of graphene layers and dielectric constant. The obtained results demonstrate that GTUNNETTs with optimized structure can be used in efficient terahertz oscillators.

Semenenko, V. L.; Leiman, V. G.; Arsenin, A. V.; Mitin, V.; Ryzhii, M.; Otsuji, T.; Ryzhii, V.

2013-01-01

204

Who is using snus? - Time trends, socioeconomic and geographic characteristics of snus users in the ageing Swedish population  

PubMed Central

Background The prevalence of smoking in Sweden has decreased in recent decades, and is now among the lowest in the world. During the same period, the use of Swedish moist oral snuff, a smokeless tobacco called snus, has increased. Few studies have evaluated time trends of the socioeconomic and geographic characteristics of snus users in Sweden. This paper contributes to filling that gap. Methods This study utilized the Linnaeus Database, which links national registers with comprehensive individual data on socioeconomic status (SES) to health data from a large ongoing health survey, the Västerbotten Intervention Programme (VIP). The VIP targets the entire middle-aged population of Västerbotten county at ages 40, 50 and 60 years with yearly cross-sectional surveys including self-reported data on tobacco habits. Time trends of snus use among 92,563 VIP-participants across different areas of residence and smoking groups were investigated graphically. Logistic regression was performed to estimate the associations between SES and geographical variables and current use versus non-use of snus. Results Overall, in parallel to decreasing smoking, the increasing trend of snus use in this middle-aged population continues, particularly in 40-year-olds. In both genders, the highest prevalence of snus use was observed among previous smokers. The prevalence of snus use also increased over time among smokers, and was consistently higher compared to those who had never smoked. Among males - both those who had never smoked and previous smokers - low education (OR 1.21, 95%CI 1.06-1.40 and OR 1.28, 95%CI 1.14-1.43), living alone (OR 1.16, 95%CI 1.07-1.27 and OR 1.13, 95%ci 1.04-1.23), low income and living in rural areas was associated with using snus, while this was not seen among male current smokers. Among women, living alone was associated with using snus irrespective of smoking habits. Among female smokers, the OR for snus use increased with higher education. Conclusions A disadvantaged social profile and also higher prevalence in rural areas is observed among male snus users who had never smoked or were previous smokers. Among male smokers there was no association between SES and use of snus. The prevalence of snus use among women is increasing, but is still considerably lower than that of men. The association between snus and SES characteristics is less pronounced among women, although snus is clearly linked to living alone. These patterns should be taken into consideration in tobacco control policies.

2011-01-01

205

Time.  

ERIC Educational Resources Information Center

Presents brief annotations of 41 children's books that explore the concept of time from varied perspectives to elucidate some of its meanings for children. Groups books to focus on milestones in children's lives; how they enjoy spending their time; visiting the past in suspending time; recognizing different ways to mark time; celebrating special…

Matthews, Susan; Reid, Rebecca; Sylvan, Anne; Woolard, Linda; Freeman, Evelyn B.

1999-01-01

206

Effects of slaughter time post-second injection on carcass cutting yields and bacon characteristics of immunologically castrated male pigs.  

PubMed

Body weights of finishing pigs can be variable within a finishing barn near the time of slaughter; therefore, it is common to market pigs over a period of time. This allows lighter pigs more time to gain BW and approach a desired end point. Use of immunological castration late in life to control boar taint, as an alternative to physical castration early in life, increases cutting yields of finishing male pigs compared with physical castrates. Because of common marketing strategies, it is important for advantages in cutting yields to span a broad spectrum of slaughter ages and BW. The primary objectives in this study were to evaluate carcass cutting yields, pork quality, belly quality, and bacon processing characteristics of immunologically castrated (IC) male pigs fed a moderate level of distillers dried grains with solubles and slaughtered at either 4 wk (early slaughter group) or 6 wk (late slaughter group) post-second injection. A total of 156 male pigs (physical castrates or IC males) were selected from a population of 1,200 finishing pigs. Data were analyzed with the MIXED procedure of SAS as a split-split plot design. Body weights of IC males were 3.60 kg heavier (P = 0.03) than physical castrates when slaughtered at 4 wk post-second injection and 7.52 kg heavier (P < 0.0001) than physical castrates when slaughtered at 6 wk post-second injection. Because of a lack of interaction (P > 0.05) between sex and time of slaughter post-second injection, some response variables were pooled. Hot carcass weights were not different (P = 0.57) between physical castrates (91.98 kg) and IC males (92.52 kg). There was a 2.77 percentage unit decrease (P < 0.001) in dressing percentage of IC males (71.78%) compared with physical castrates (74.55%). Lean cutting yields of IC males were 2.62 percentage units greater (P < 0.0001) than physical castrates and carcass cutting yields were 2.27 percentage units greater (P < 0.0001) for IC males when compared with physical castrates. There were no differences between IC males and physical castrates for shear force (P = 0.09), ultimate pH (P = 0.57), objective color (P ? 0.31), subjective color score (P = 0.64), or drip loss (P = 0.30). Bellies from IC males were thinner (P = 0.01) and had narrower belly flops (P < 0.0001) than bellies from physical castrates. There were no differences (P = 0.74) in cured belly cooked yield between IC males and physical castrates. Overall, immunological castration improved cutting yields, did not affect pork quality, made fresh bellies thinner, and did not affect cured belly characteristics when pigs were fed a moderate level of distillers dried grains with solubles during the finishing phase of production. PMID:21890506

Boler, D D; Killefer, J; Meeuwse, D M; King, V L; McKeith, F K; Dilger, A C

2011-09-02

207

Time-dependent adaptations to posture and movement characteristics during the development of repetitive reaching induced fatigue.  

PubMed

Repetitive movements are common to many daily activities but often lead to the development of fatigue. We have previously shown that fatigue leads to changes in tridimensional spatial characteristics of the whole body. However, temporal aspects of these posture and movement adaptations have yet to be investigated. Healthy subjects (N = 14) performed a continuous reaching task by pointing between two targets placed at shoulder height, at 100 and 30% arm's length, anterior to the subject's midline until fatigue (assessed using the Borg CR-10 scale). Whole body kinematics and upper Trapezius EMG were recorded and analyzed at 1-min intervals to document the progression of fatigue on outcome variables. For all upper limb and postural variables analyzed, changes began to occur approximately midway to fatigue and were followed by an increase in Trapezius activity from baseline. Reach-to-reach variability of joint average positions and range of motion (ROM) increased in multiple directions for shoulder and elbow parameters. Reach-to-reach variability of the center-of-mass ROM also increased in several directions. Changes were also observed in within-movement inter-segmental timing. The peak velocities of elbow and endpoint occurred closer together in time during fatigue while the shoulder peak velocity occurrence showed a greater reach-to-reach variability. Our results suggest that the effects of fatigue on repetitive movement kinematics can be observed across three temporal dimensions of the task: (1) within individual movements, (2) from one movement to the next, and (3) as fatigue develops. Each observed change is discussed as a potential contributor to task-specific control strategies to prolong task performance. PMID:21484395

Fuller, Jason R; Fung, Joyce; Côté, Julie N

2011-04-12

208

Study of the main geochemical characteristics of Phobos' regolith using laser time-of-flight mass spectrometry  

NASA Astrophysics Data System (ADS)

The peculiarities of the airborne LAZMA instrument applied for the measurement of the isotopic and elemental composition of Phobos’ regolith by the method of laser time-of-flight mass spectrometry are discussed. These measurements may confirm the assumptions that the material of Phobos is an initial substance with a composition close to carbonaceous chondrites, from which the Earth was formed. The results of the measurements may also confirm the original mechanism of the formation of the anomalous absorption of Phobos’ regolith suggested in this study. The obtained results regarding the elemental composition of the regolith may contain information about the conditions of the formation of Phobos, as well as provide information about it age. The scientific tasks of individual experiments and ways for their realization are considered in the paper. A detailed description of the airborne instrument and the principle of its operation is presented. The analytical and technical characteristics of the instrument and the peculiarities of constructive decisions are given. Data on the most important functional assemblies of the instrument, the development and transmission of scientific information to the Earth, are considered. The mass spectra presented in the paper were obtained by airborne instruments during the course of their laboratory test and the selection of the operating regime. It is demonstrated that the LAZMA instrument is the first version of the original next-generation airborne instrument constructed at the Space Research Institute and patented in Russia.

Managadze, G. G.; Wurz, P.; Sagdeev, R. Z.; Chumikov, A. E.; Tuley, M.; Yakovleva, M.; Managadze, N. G.; Bondarenko, A. L.

2010-10-01

209

Biomass characteristics and simultaneous nitrification-denitrification under long sludge retention time in an integrated reactor treating rural domestic sewage.  

PubMed

In this work, a novel integrated reactor incorporating anoxic fixed bed biofilm reactor (FBBR), oxic moving bed biofilm reactor (MBBR) and settler sequentially was proposed for nitrogen removal from rural domestic sewage. For purposes of achieving high efficiency, low costs and easy maintenance, biomass characteristics and simultaneous nitrification-denitrification (SND) were investigated under long sludge retention time during a 149-day period. The results showed that enhanced SND with proportions of 37.7-42.2% tapped the reactor potentials of efficiency and economy both, despite of C/N ratio of 2.5-4.0 in influent. TN was removed averagely by 69.3% at least, even under internal recycling ratio of 200% and less proportions of biomass assimilation (<3%). Consequently, lower internal recycle and intermittent wasted sludge discharge were feasible to save costs, together with cancellations of sludge return and anoxic stir. Furthermore, biomass with low observed heterotrophic yields (0.053 ± 0.035 g VSS/g COD) and VSS/TSS ratio (<0.55) in MBBR, simplified wasted sludge disposal. PMID:22750493

Gong, Lingxiao; Jun, Li; Yang, Qing; Wang, Shuying; Ma, Bin; Peng, Yongzhen

2012-05-23

210

A study of Time\\/Current Characteristics of the Ignition Processes in Cellulosic Material Caused by Electrical Arcing for Application in 240V Arc-Fault Circuit Interrupters  

Microsoft Academic Search

In the development of Arc-Fault Circuit interrupters (AFCIs), one of the most important parameters is the time that an arcing fault could persist before the device will interrupt the current flow and hopefully mitigate fire propagation. In 1996 Underwriters laboratories (UL) published a report on time\\/current ignition characteristics of arcs at 120 V. Despite the very limited number of tests

D. Kolker; S. Campolo; N. DiSalvo

2007-01-01

211

Energy Consumption and Its Reduction in the Hydrocyclone Separation Process. II. Time-Averaged and Fluctuating Characteristics of the Turbulent Pressure in a Hydrocyclone  

Microsoft Academic Search

A resistance wire strain gauge system was used to experimentally study time-averaged and fluctuating characteristics of turbulent pressure in a hydrocyclone for the first time. In the main space inside the hydrocyclone, pressure distribution could be described with a mathematical model in which pressure is a function of positional radius. When positional radius decreases, pressure drops, but the radial gradient

LIANG-YIN CHU; JIAN-JUN QIN; WEN-MEI CHEN; XIAO-ZHONG LEE

2000-01-01

212

Linear and nonlinear characteristics of heart rate time series in obesity and during weight-reduction surgery.  

PubMed

Obesity is associated with abnormal cardiac regulation by the autonomic nervous system (ANS), this being reversed by weight loss. Bariatric (weight-reduction) surgery can induce substantial long-term weight reductions. This study compares the acute influence on ANS control of two different types of bariatric surgery involving laparascopic and open procedures. To distinguish between the cardiac influences of surgery and obesity, we perform the same analysis for laparascopic surgery in non-obese patients. Eight morbidly obese and five non-obese patients underwent surgery. Obese patients received either laparoscopic procedures (group A: n = 5, BMI = 44.3 +/- 2.7 kg m(2)) or open procedures (group B: n = 3, BMI = 55.2 +/- 4.5 kg m(2)) and non-obese patients received a laparoscopic procedure (group C: n = 5, BMI = 30.8 +/- 5.8 kg m(-2)). Holter ECG was recorded and heart rate variability (HRV) was quantified together with measures of complexity (sample entropy) and structure (Hurst coefficient, scaling coefficient) of the heart rate data. Multifractal characteristics of heart rate data, not previously reported for obese patients, are also quantified and interpreted. Mixed model ANOVA was used to assess the magnitudes of each quantified variable, with surgical group and perioperative time as main factors. HRV measures were influenced only during anaesthesia (LFn increase: p = 0.009; HFn decrease: p = 0.033) and did not discriminate between patient groups. Multifractality was the only characteristic of heart rate data that discriminated between patient groups, being significantly (p < 0.001) greater in non-obese (group C) compared with obese patients (groups A and B, who had similar multifractal properties). Multifractality was also enhanced during anaesthesia (p = 0.028) but did not differ for other stages. We conclude that obesity per se rather than response to surgery is the cause of reduced multifractality. Reduced multifractality in obesity might reflect a diminished 'scaling' or 'collective response' across the multiple autonomic modulators of heart rate. The multifractal method appears to be a more sensitive measure of integrated cardiac autonomic function than linear methods for these patients. PMID:19458410

Alam, I; Lewis, M J; Morgan, J; Baxter, J

2009-05-21

213

Detection of Characteristic Precipitation Anomaly Patterns of El Nino / La Nina in Time- variable Gravity Fields by GRACE  

NASA Astrophysics Data System (ADS)

GRACE (Gravity Recovery and Climate Experiment) satellites, launched in March 2002, have been mapping monthly gravity fields of the Earth, allowing us to infer changes in surface mass, e.g. water and ice. Past findings include the ice mass loss in southern Greenland (Luthcke et al., 2006) and its acceleration in 2004 (Velicogna and Wahr, 2006), crustal dilatation by the 2004 Sumatra Earthquake (Han et al., 2006) and the postseismic movement of water in mantle (Ogawa and Heki, 2007). ENSO (El Nino and Southern Oscillation) brings about global climate impacts, together with its opposite phenomenon, La Nina. Ropelewski and Halpert (1987) showed typical precipitation patterns in ENSO years; characteristic regional-scale precipitation anomalies occur in India, tropical and southern Africa and South America. Nearly opposite precipitation anomalies are shown to occur in La Nina years (Ropelewski and Halpert, 1988). Here we report the detection of such precipitation anomaly patterns in the GRACE monthly gravity data 2002 - 2007, which includes both La Nina (2005 fall - 2006 spring) and El Nino (2006 fall - 2007 spring) periods. We modeled the worldwide gravity time series with constant trends and seasonal changes, and extracted deviations of gravity values at two time epochs, i.e. February 2006 and 2007, and converted them into the changes in equivalent surface water mass. East Africa showed negative gravity deviation (-20.5 cm in water) in 2006 February (La Nina), which reversed to positive (18.7 cm) in 2007 February (El Nino). Northern and southern parts of South America also showed similar see-saw patterns. Such patterns closely resemble to those found meteorologically (Ropelewski and Halpert, 1987; 1988), suggesting the potential of GRACE as a sensor of inter-annual precipitation anomalies through changes in continental water storage. We performed numerical simulations of soil moisture changes at grid points in land area incorporating the CMAP precipitation data, NCEP/NCAR temperature data, and potential evapotranspiration calculated after Thornswaite (1942). We took out the soil moisture anomalies in 2006 February and 2007 February by modeling its time series in the same way as gravity, and confirmed that they are quantitatively consistent with GRACE gravity deviations. Out study demonstrates that satellite gravity data can detect not only of global warming signals in high latitude regions but also inter-annual climate changes in low and middle latitude continental regions.

Heki, K.; Morishita, Y.

2007-12-01

214

Measurement of Sparkover Voltage and Time Lag Characteristics in SF6-N2 Gas Mixtures by using Steep-front Square Voltage  

NASA Astrophysics Data System (ADS)

A square pulse voltage is useful for studying electrical discharge physics and/or very fast transient overvoltage issues. This paper describes sparkover voltages and time lag (V-t) characteristics of SF6-N2 gas mixtures in a very short time range below a microsecond, which are measured by using a steep-front square voltage with a rise time of 16 nanoseconds and a peak value of 200 kilovolts. SF6-N2 gas mixture, which contains nitrogen gas at a ratio of 60 % or less, has equivalent dielectric strength to pure SF6 gas even in the short time range around 10 nanoseconds. Sparkover voltage and time lag characteristics are evaluated by using the equal area criterion even in the short time range below a microsecond.

Toyota, Hiroyuki; Matsuoka, Shigeyasu; Hidaka, Kunihiko

215

The Characteristic of Heat Wave Effects on Coronary Heart Disease Mortality in Beijing, China: A Time Series Study  

PubMed Central

Background There is limited evidence for the impacts of heat waves on coronary heart disease (CHD) mortality in Beijing, capital city of China. Objectives We aimed to find a best heat wave definition for CHD mortality; and explore the characteristic of heat wave effects on CHD in Beijing, China. Methods We obtained daily data on weather and CHD mortality in Beijing for years 2000–2011. A quasi-Poisson regression model was used to assess the short-term impact of heat waves on CHD mortality in hot season (May–September), while controlling for relative humidity, day of the week, long-term trend and season. We compared 18 heat wave definitions by combining heat wave thresholds (87.5th, 90.0th, 92.5th, 95th, 97.5th, and 99th percentile of daily mean temperature) with different duration days (? 2 to ? 4 days), using Akaike information criterion for quasi-Poisson. We examined whether heat wave effects on CHD mortality were modified by heat wave duration and timing. Results Heat wave definition using 97.5th percentile of daily mean temperature (30.5 °C) and duration ? 2 days produced the best model fit. Based on this heat wave definition, we found that men and elderly were sensitive to the first heat waves of the season, while women and young were sensitive to the second heat waves. In general, the longer duration of heat waves increased the risks of CHD mortality more than shorter duration for elderly. The first two days of heat waves had the highest impact on CHD mortality. Women and elderly were at higher risks than men and young when exposed to heat waves, but the effect differences were not statistically significant. Conclusions Heat waves had significant impact on CHD mortality. This finding may have implications for policy making towards protecting human health from heat waves.

Tian, Zhaoxing; Li, Shanshan; Zhang, Jinliang; Guo, Yuming

2013-01-01

216

Antecedents and consequences of separation anxiety in first-time mothers: infant, mother, and social-contextual characteristics  

Microsoft Academic Search

Maternal separation anxiety is an unpleasant emotional state of worry, guilt, and sadness experienced by mothers during a short-term separation from their infant (Hock, McBride, & Gnezda, 1989). Guided by Belsky’s [Child Dev. 55 (1984) 83] multidimensional model of parenting, influences of the three major determinants of parenting, namely maternal characteristics, social-contextual resources, and infant characteristics, on individual differences in

Hui-Chin Hsu

2004-01-01

217

Epidemiology of leisure-time physical activity in socio-demographic, lifestyle and psychological characteristics of men and women in Greece: the ATTICA Study  

Microsoft Academic Search

BACKGROUND: We aimed to evaluate the prevalence, frequency and type of leisure-time physical activity (LTPA) among adults in Greece, as well as its relationship with socio-demographic, lifestyle and clinical characteristics of these people. METHODS: From May 2001 to December 2002 we randomly enrolled 1514 men and 1528 women, without any evidence of cardiovascular or any other chronic disease. The sampling

Christos Pitsavos; Demosthenes B Panagiotakos; Yannis Lentzas; Christodoulos Stefanadis

2005-01-01

218

First-Time Parents' Prenatal to Postpartum Changes in Health, and the Relation of Postpartum Health to Work and Partner Characteristics  

Microsoft Academic Search

Background: The purpose of this study was to evaluate prenatal to postnatal changes in first-time par- ents' physical and mental health, and to describe social and health predictors of parents' postpartum health. Methods: This prospective study surveyed 261 expectant fathers and mothers during pregnancy and again at 6 months' postpartum regarding their health, partner, and work characteristics. Postpartum changes in

Dwenda K. Gjerdingen

219

Influence of static injection timing on combustion, emission and performance characteristics of DI diesel engine fuelled with honne oil methyl ester  

Microsoft Academic Search

This study is aimed to investigate experimentally the combustion, exhaust emissions and performance characteristics of a direct injection (DI) diesel engine, typically used in the agricultural sector, when fuelled with neat diesel (ND), and abundantly available but untapped honne oil methyl ester (HOME) is used in diesel engines. The static injection timing (SIT) is varied from 23 crank angle (CA)

Venkanna Krishnamurthy Belagur; Venkataramana Reddy Chitimini

2011-01-01

220

Influence of static injection timing on combustion, emission and performance characteristics of DI diesel engine fuelled with honne oil methyl ester  

Microsoft Academic Search

This study is aimed to investigate experimentally the combustion, exhaust emissions and performance characteristics of a direct injection (DI) diesel engine, typically used in the agricultural sector, when fuelled with neat diesel (ND), and abundantly available but untapped honne oil methyl ester (HOME) is used in diesel engines. The static injection timing (SIT) is varied from 23 crank angle (CA)

Venkanna Krishnamurthy Belagur; Venkataramana Reddy Chitimini

2012-01-01

221

Nonlinear characteristics of heart rate time series: influence of three recumbent positions in patients with mild or severe coronary artery disease  

Microsoft Academic Search

The aim of this study was to investigate the nonlinear characteristics of heart rate variability (HRV) for three recumbent positions: the supine, left lateral and right lateral decubitus positions. Recently, using a linear analyses method (for time and frequency domains), the effect of the right lateral decubitus position on vagal modulation has been found to increase parasympathetic activity and decrease

Wuon-Shik Kim; Young-Zoon Yoon; Jang-Ho Bae; Kwang-Sup Soh

2005-01-01

222

Propagation through nonlinear time-dependent bubble clouds and the estimation of bubble populations from measured acoustic characteristics  

Microsoft Academic Search

For several decades the propagation characteristics of acoustic pulses (attenuation and sound speed) have been inverted in attempts to measure the size distributions of gas bubbles in liquids. While this has biomedical and industrial applications, most notably it has been attempted in the ocean for defence and environmental purposes, where the bubbles are predominantly generated by breaking waves. Such inversions

T. G. Leighton; S. D. Meers; P. R. White

2004-01-01

223

Three list scheduling temporal partitioning algorithm of time space characteristic analysis and compare for dynamic reconfigurable computing  

NASA Astrophysics Data System (ADS)

Level Based Partitioning (LBP) algorithm, Cluster Based Partitioning (CBP) algorithm and Enhance Static List (ESL) temporal partitioning algorithm based on adjacent matrix and adjacent table are designed and implemented in this paper. Also partitioning time and memory occupation based on three algorithms are compared. Experiment results show LBP partitioning algorithm possesses the least partitioning time and better parallel character, as far as memory occupation and partitioning time are concerned, algorithms based on adjacent table have less partitioning time and less space memory occupation.

Chen, Naijin

2013-03-01

224

Trapped field characteristics of Y-Ba-Cu-O bulk in time-varying external magnetic field  

Microsoft Academic Search

It is very important to clarify characteristics of trapped field in HTS bulk exposed to an external AC magnetic field in application of high-temperature superconducting bulk to motors, magnetic levitation systems, bulk magnets and so on. We have experimentally investigated the transition of trapped field while applying external AC magnetic field to a disk-shaped YBCO bulk. The observed trapped-field attenuation

Hidehito Shimizu; Hiroshi Ueda; Makoto Tsuda; Atsushi Ishiyama

2002-01-01

225

Turbulence characteristics of the noise producing region of an excited round jet. I - Time-average flow properties  

Microsoft Academic Search

Experiments were conducted to determine the mean turbulence characteristics of the noise-producing region of a 3 in. cold excited round jet. The jet was excited by plane acoustic waves with a high amplitude of excitation (2 percent of the jet dynamic head), and at a Strouhal number of 0.5. The flow Reynolds number was 280,000. The exit boundary layer was

C. Baltas; P. J. Morris

1984-01-01

226

Real-time wireless monitoring of workpiece material and debris characteristics in micro-electro-discharge machining  

Microsoft Academic Search

Wireless signals are generated with each discharge in micro-electro-discharge machining (muEDM), providing an opportunity to directly monitor discharge quality. Unlike traditional methods of monitoring progress in machining, which rely on electrical characteristics at the discharge supply terminals, this method is less affected by parasitics. The depth location of a metal-metal interface can be distinguished in the wireless signal. This is

Mark T. Richardson; Yogesh B. Gianchandani

2008-01-01

227

Correlation of laminar-turbulent transition data over flat plates in supersonic\\/hypersonic flow including leading edge bluntness effects  

Microsoft Academic Search

The paper discusses flat plate boundary layer transition in supersonic\\/hypersonic flow conditions. Examination of experimental infrared thermography data illustrates the importance of the leading edge thickness and (non-) uniformity to the transition process. Such observations have triggered the collection of a wide range of experimental data on supersonic\\/hypersonic flat plate boundary layer transition, and a number of attempts to correlate

G. A. Simeonides; Rio Patras

2003-01-01

228

Calculation of Diffraction Characteristics of Sub wavelength Conducting Gratings Using a High Accuracy Nonstandard Finite-Difference Time-Domain Method  

NASA Astrophysics Data System (ADS)

Gratings with subwavelength groove depth and period are frequently used in optics for various purposes. The polarization dependent diffraction characteristics of subwavelength (high frequency) gratings can only be calculated by solving Maxwell’s equations of electromagnetism. In this paper, we calculate the classical diffraction characteristics of subwavelength conducting gratings numerically, using a new high accuracy version of nonstandard finite-difference time-domain (NS-FDTD) algorithm. For the purpose of analysis, we employ a gold sinusoidal grating with light incident at a large angle. We have compared high accuracy NS-FDTD simulation results with those obtained from standard finite-difference time-domain (S-FDTD), and the finite element method (FEM) simulations.

Banerjee, Saswatee; Cole, James B.; Yatagai, Toyohiko

229

Engaging nursing home residents with dementia in activities: The effects of modeling, presentation order, time of day, and setting characteristics  

PubMed Central

We examined the impact of setting characteristics and presentation effects on engagement with stimuli in a group of 193 nursing home residents with dementia (recruited from a total of seven nursing homes). Engagement was assessed through systematic observations using the Observational Measurement of Engagement (OME), and data pertaining to setting characteristics (background noise, light, and number of persons in proximity) were recorded via the environmental portion of the Agitation Behavior Mapping Inventory (ABMI; Cohen-Mansfield, Werner, & Marx, (1989). An observational study of agitation in agitated nursing home residents. International Psychogeriatrics, 1, 153–165). Results revealed that study participants were engaged more often with moderate levels of sound and in the presence of a small group of people (from four to nine people). As to the presentation effects, multiple presentations of the same stimulus were found to be appropriate for the severely impaired as well as the moderately cognitively impaired. Moreover, modeling of the appropriate behavior significantly increased engagement, with the severely cognitively impaired residents receiving the greatest benefit from modeling. These findings have direct implications for the way in which caregivers could structure the environment in the nursing home and how they could present stimuli to residents in order to optimize engagement in persons with dementia.

Cohen-Mansfield, Jiska; Thein, Khin; Dakheel-Ali, Maha; Marx, Marcia S.

2011-01-01

230

Real-time demonstration of the main characteristics of chaos in the motion of a real double pendulum  

NASA Astrophysics Data System (ADS)

Several studies came to the conclusion that chaotic phenomena are worth including in high school and undergraduate education. The double pendulum is one of the simplest systems that is chaotic; therefore, numerical simulations and theoretical studies of it have been given large publicity, and thanks to its spectacular motion, it has become one of the most famous demonstration tools of chaos, either through simulations or in real experiments. Although several attempts have been made to use the experiment in laboratory exercises, as the friction in the real experiment changes the nature of the motion and the values of characteristic parameters during the motion, examining the measured (dissipative) motion and comparing it with theoretical results raises several questions. In our review, we present a measurement system which is able to analyse these questions. The system, which consists of simple yet precise data acquisition electronics, easily attainable sensors, a Bluetooth module (to communicate with the PC) and open-source software, demonstrates on-line the main characteristics of chaos and the methods of its study and allows us to analyse the dissipative motion. Further information (including downloadable software) is provided on a dedicated page, http://www.inf.u-szeged.hu/noise/Research/DoublePendulum/.

Vadai, Gergely; Gingl, Zoltán; Mellár, János

2012-07-01

231

Space-Time Characteristics of the Turbulent Flow Energy in a Viscoelastic Medium Using Noninvasive Passive Imaging.  

National Technical Information Service (NTIS)

This report describes the technology required for noninvasive passive imaging of the turbulent flow energy of space-time signals in a viscoelastic medium. The need for such technology emerges from the field of biomedicine, where low cost noninvasive techn...

N. L. Owsley M. H. Ahmed A. J. Hull J. Kassal

1995-01-01

232

Numerical and experimental studies of mixing characteristics in a T-junction microchannel using residence-time distribution  

Microsoft Academic Search

The mixing behavior in laminar flow in microchannels is investigated using numerical and experimental approaches. The concept of residence-time distribution (RTD) was applied to indirectly characterize flow and mixing in a T-junction microchannel chosen as a model microchannel mixer\\/reactor. The residence-time distribution used in this study, although a well-known method for characterizing mixing behavior in conventional macro mixers\\/reactors, is still

John T. Adeosun; Adeniyi Lawal

2009-01-01

233

New space-time perspectives on the propagation characteristics of the Black Death epidemic and its relation to bubonic plague  

Microsoft Academic Search

This work presents, for the first time, a series of detailed space-time maps of Black Death mortality and infected area propagation\\u000a throughout the fourteenth century AD Europe. The maps integrate a variety of interdisciplinary knowledge bases about the devastating\\u000a epidemic and provide researchers and the interested public with an informative description of the Black Death dynamics (temporal\\u000a evolution, local and

George Christakos; Ricardo A. Olea

2005-01-01

234

Influencing Work-Related Learning: The Role of Job Characteristics and Self-Directed Learning Orientation in Part-Time Vocational Education  

Microsoft Academic Search

Based on the Demand-Control-Support (DCS) model, the present paper aims to investigate the influence of job characteristics\\u000a such as job demands, job control, social support at work and self-directed learning orientation on the work-related learning\\u000a behaviour of workers. The present study was conducted in a centre for part-time vocational education in Flanders (Belgium).\\u000a The students in the centre work for

David Gijbels; Isabel Raemdonck; Dries Vervecken

2010-01-01

235

Mapping forest height, foliage height profiles and disturbance characteristics with time series of gap-filled Landsat and ALI imagery  

NASA Astrophysics Data System (ADS)

We mapped tropical dry forest height (RMSE = 0.9 m, R2 = 0.84, range 0.6-7 m) and foliage height profiles with a time series of gap-filled Landsat and Advanced Land Imager (ALI) imagery for the island of Eleuthera, The Bahamas. We also mapped disturbance type and age with decision tree classification of the image time series. Having mapped these variables in the context of studies of wintering habitat of an endangered Nearctic-Neotropical migrant bird, the Kirtland's Warbler (Dendroica kirtlandii), we then illustrated relationships between forest vertical structure, disturbance type and counts of forage species important to the Kirtland's Warbler. The ALI imagery and the Landsat time series were both critical to the result for forest height, which the strong relationship of forest height with disturbance type and age facilitated. Also unique to this study was that seven of the eight image time steps were cloud-gap-filled images: mosaics of the clear parts of several cloudy scenes, in which cloud gaps in a reference scene for each time step are filled with image data from alternate scenes. We created each cloud-cleared image, including a virtually seamless ALI image mosaic, with regression tree normalization of the image data that filled cloud gaps. We also illustrated how viewing time series imagery as red-green-blue composites of tasseled cap wetness (RGB wetness composites) aids reference data collection for classifying tropical forest disturbance type and age.

Helmer, E.; Ruzycki, T. S.; Wunderle, J. M.; Kwit, C.; Ewert, D. N.; Voggesser, S. M.; Brandeis, T. J.

2011-12-01

236

Time-Series Analyses of Supergranule Characteristics Compared Between SDO/HMI, SOHO/MDI and Simulated Datasets  

NASA Astrophysics Data System (ADS)

Supergranulation is a well-observed solar phenomenon despite its underlying mechanisms remaining a mystery. Originally considered to arise due to convective motions, alternative mechanisms have been suggested such as the cumulative downdrafts of granules as well as displaying wave-like properties. Supergranule characteristics are well documented, however. Supergranule cells are approximately 35 Mm across, have lifetimes on the order of a day and have divergent horizontal velocities of around 300 m/s, a factor of 10 higher than their central radial components. While they have been observed using Doppler methods for more than half a century, their existence is also observed in other datasets such as magnetograms and Ca II K images. These datasets clearly show the influence of supergranulation on solar magnetism and how the local field is organized by the flows of supergranule cells. The Heliospheric and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO) continues to produce Doppler images enabling the continuation of supergranulation studies made with SOHO/MDI, but with superior temporal and spatial resolution. The size-distribution of divergent cellular flows observed on the photosphere now reaches down to granular scales, allowing contemporaneous comparisons between the two flow components. SOHO/MDI Doppler observations made during the minima of cycles 22/23 and 23/24 exhibit fluctuations of supergranule characteristics (global averages of the supergranule size, size-range and horizontal velocity) with periods of 3-5 days. Similar fluctuations have been observed in SDO/HMI Dopplergrams and the high correlation between co-temporal HMI & MDI suggest a solar origin. Their nature has been probed by invoking data simulations that produce realistic Dopplergrams based on MDI data.

Williams, P. E.; Pesnell, W. D.

2011-12-01

237

Investigation of Thermal Conductivity and Heat Characteristics of Oil Sands Using Ultrasound Irradiation for Shortening the Preheating Time  

NASA Astrophysics Data System (ADS)

Oil sands are attractive as an energy resource. Bitumen, which is found in oil sands, has high viscosity, so that it does not flow. Most oil sands are underground and are developed with a method called steam-assisted gravity drainage (SAGD). Hot steam is injected underground to fluidize bitumen and promote its recovery. However, the preheating time is too long. One way of reducing running costs is by shortening the preheating time. Previous studies have found that bitumen can be extracted from oil sands efficiently by applying ultrasonic irradiation, but SAGD was not applied directly in these cases. Thus, the purpose of this study is to apply ultrasonic irradiation to SAGD, thereby shortening the preheating time of oil sands. As a model experiment for SAGD, heat transfer experiments in a sand layer made with Toyoura sand and silicone oil were conducted and the thermal effect with ultrasound was investigated.

Kamagata, Shingo; Kawamura, Youhei; Okawa, Hirokazu; Mizutani, Koichi

2012-07-01

238

Effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover using combination of steam explosion and microwave irradiation (SE-MI) pretreatment.  

PubMed

The effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover were investigated based on a new process named combination of steam explosion and microwave irradiation (SE-MI) pretreatment. Results showed that with microwave power and microwave irradiation time increasing, glucose and xylose that released into hydrolyzate, as well as enzymatic hydrolysis yields and sugar yields of glucose and xylose were all slightly increased after SE-MI pretreatment. The maximum sugar yield was 72.1 g per 100 g glucose and xylose in feedstock, achieved at 540 W microwave power and 5 min microwave irradiation time. XRD analysis showed that the crystallinity of biomass was 15.6-19.9% lower for SE-MI pretreatment with microwave effect than that without microwave effect. However, low microwave power and short microwave irradiation time were favorable for SE-MI pretreatment considering energy consumption. PMID:22705513

Pang, Feng; Xue, Shulin; Yu, Shengshuan; Zhang, Chao; Li, Bing; Kang, Yong

2012-05-18

239

Compliance to a Cell Phone-Based Ecological Momentary Assessment Study: The Effect of Time and Personality Characteristics  

ERIC Educational Resources Information Center

|Ecological momentary assessment (EMA) is a method that is now widely used to study behavior and mood in the settings in which they naturally occur. It maximizes ecological validity and avoids the limitations of retrospective self-reports. Compliance patterns across time have not been studied. Consistent compliance patterns could lead to data not…

Courvoisier, Delphine S.; Eid, Michael; Lischetzke, Tanja

2012-01-01

240

Characteristics of gelatin from the skin of unicorn leatherjacket ( Aluterus monoceros) as influenced by acid pretreatment and extraction time  

Microsoft Academic Search

Gelatins from the skin of unicorn leatherjacket (Aluterus monoceros) pretreated with different acids (0.2M acetic acid or 0.2M phosphoric acid) and extracted with distilled water at 45°C for various times (4 and 8h) were characterized. Yields of 5.23–9.18 or 6.12–11.54% (wet weight basis) were obtained for gelatins extracted from the skin pretreated with 0.2M acetic acid or 0.2M phosphoric acid,

Mehraj Ahmad; Soottawat Benjakul

2011-01-01

241

Growth characteristics of human adipose-derived stem cells during long time culture regulated by cyclin a and cyclin D1.  

PubMed

Abundant and less passaged cells are highly expected in clinical application since repeated subculture reduces stem cell characteristics. Long time culture of stem cells without passage is therefore needed. The growth and cell viability of human adipose-derived stem cells (hADSCs) were investigated by live/dead staining, cck-8 kits, and hemocytometer every day in 30 days of culture. The stem cell characteristics of hADSCs at the beginning and the end of culture were detected by flow cytometry and histochemical staining. hADSCs can be cultured up to the 30th day in one passage while maintaining high level cell viability and their stem cell characteristics. In addition, the cells displayed two plateau phases and three logarithmic phases during 1 month of culture. Increasing expression of cyclin A at protein level resulted in an increase in the percentage of hADSCs in the S and G(2)/M phases, while decreasing protein level of cyclin D1 induced a decline in the proportion of hADSCs in the G(0)/G(1) phase, regulating cells to move into rapid proliferation. This study demonstrates that a great quantity of hADSCs can be obtained in vitro by prolonging the culture time of each passage. And cyclin A and cyclin D1 affect the distribution of cell cycle and regulate the growth of hADSCs. PMID:23076572

Jiang, Lili; Liu, Tianqing; Song, Kedong

2012-10-18

242

Effects of different lairage times after long distance transportation on carcass and meat quality characteristics of Hungarian Simmental bulls.  

PubMed

The objective of this study was to determine the effects of three lairage times (24h, 48h and 72h) on the meat quality of tame trained to lead Hungarian Simmental bulls subjected to long commercial transportation of approximately 1800km. A total of 30 bulls, with an average age of 24months, were used. During the lairage, bulls received 0.5kg concentrate feed per animal per day and ad libitum access to the hay and water. As the lairage duration increased, the pHult decreased (P<0.05). Bulls lairaged for 24h had lower L*, b* and H* values than those lairaged for 48h and 72h (P<0.05). The effect of lairage time on WHC, cooking loss and Warner-Bratzler shear force values was not significant. The b* value was considered the best predictor of muscle pHult. In conclusion, 72h quiet lairage time is recommended after transportation in order to prevent the adverse effects of transportation on meat quality. PMID:23916957

Teke, Bulent; Akdag, Filiz; Ekiz, Bulent; Ugurlu, Mustafa

2013-07-13

243

[Time lag characteristics of stem sap flow of common tree species during their growth season in Beijing downtown].  

PubMed

From April to September in 2008, the stem sap flow velocity (Js) of several common tree species (Ginkgo biloba, Aesculus chinensis, Magnolia denudata, Robinia pseudoacacia, Pinus tabulaeformis and Cedrus deodara) in Beijing was measured by thermal dissipation method. Crosscorrelation analysis was used to estimate the time lag between the stem sap flow and the driving factors of canopy transpiration among the tree species. The Js of the six tree species was significantly correlated with the total radiation (Rs) and vapor pressure deficit (D), and the Js was lagged behind Rs but ahead of D. The maximum correlation coefficient of Js with Rs (0.74-0.93) was often higher than that of Js with D (0.57-0.79), indicating that the diurnal Js was more dependent on Rs than on D. The sampled tree species except P. tabulaeformis had a shorter time lag of Js with Rs (10-70 min) than with D (47-130 min), and there existed significant differences among R. pseudoacacia, P. tabulaeformis, and C. deodara. The time lag between the Js and the driving factors of canopy transpiration was mainly correlated with the tree features (DBH, tree height, canopy area, and sapwood area) and the nocturnal water recharge, regardless of tree species. PMID:20030130

Wang, Hua; Ouyang, Zhi-yun; Zheng, Hua; Wang, Xiao-ke; Ni, Yong-ming; Ren, Yu-fen

2009-09-01

244

Storm-time characteristics of intense geomagnetic storms (Dst?-200nT) at low-latitudes and associatedenergetics  

NASA Astrophysics Data System (ADS)

Tremendous amount of solar energy is hurled into the space by transient sporadic emissions occurring within the Sun. A fraction of this energy is transferred into the Earth's magnetosphere by the magnetic reconnection process. Interplanetary magnetic field plays a crucial role in the excitation of geomagnetic storms and their subsequent evolution. The present study attempts to determine the influence of post-shock duration of southward Bz on the development and intensification of intense (Dst?-200nT) geomagnetic storms. The study presents 18 big storm events that occurred during the solar cycle 23. In all the cases under study, the interplanetary shocks were driven by the interplanetary coronal mass ejections (ICMEs). The ICME structures may contain southward magnetic fields within the sheath, the magnetic cloud or both in succession, which can lead to the development of intense geomagnetic storms. In addition, dependence of storm strength on the total energy influx into the magnetosphere (?) and ring current (ERC) energy is also assessed. Geomagnetic storm characteristics are examined at a low-latitude station, Alibag (geographic lat. 18.63?N, long. 72.87?E; geomagnetic lat. 10.02?N, long. 145.97?), using high resolution digital data. The minimum duration of southward Bz for strengthening the storms is ˜1.25h. All intense storms are found to have minimum values of southward directed Bz to be ?-18nT and interplanetary electric field Ey>12mV/m. Intensity of geomagnetic storms at low-latitudes follows a fairly linear dependence on the ring current energy.

Rawat, R.; Alex, S.; Lakhina, G. S.

2010-12-01

245

Characteristics of microbial communities in steppe paleosols buried under kurgans of the Sarmatian time (I-IV centuries AD)  

NASA Astrophysics Data System (ADS)

Microbiological studies of paleosols buried under steppe kurgans of different ages of the Middle (I-II centuries AD) and Late Sarmatian (II-IV centuries AD) time in different regions of the Lower Volga steppes were carried out. The regularities of the soil microbial communities’ development were determined in the I-IV centuries AD by the climate dynamics and the replacement of the relatively humid conditions (the I century to the first half of the II century) by dry (the second half of the II century to the first half of the III century) and then again by humid (the end of the III century to the IV century) conditions. In the humid climatic periods, the active biomass of the microorganisms and its portion in the total microbial biomass and the Corg of the soil increased, the portion of microorganisms consuming plant residues increased in the ecological-trophic structure of the microbial community, and the index of oligotrophy decreased. These changes had an opposite direction in the arid climatic periods. The variations of the microbiological parameters relative to the century-long dynamics of the climate over the historical time were synchronous and unidirectional, though the studied soils were found in different soil-geographical zones (dry and desert steppe), natural regions (the Privolzhskaya and Ergeni uplands and the Caspian Lowland), and landforms (watersheds, river terraces, marine plains).

Demkina, T. S.; Khomutova, T. E.; Kashirskaya, N. N.; Stretovich, I. V.; Demkin, V. A.

2009-07-01

246

Time Evolution of the H-mode Pedestal Characteristics in Type I ELM Discharges on DIII-D  

NASA Astrophysics Data System (ADS)

The time evolution of H-mode pedestal profiles leading up to a Type I edge localized mode (ELM) is studied in low ELM frequency discharges with electron cyclotron or neutral beam heating. A continuous increase of the pedestal pressure gradient, ?p^PED, and/or the edge transport barrier, ETB, width was observed in all cases. Simulations and Li-beam measurements indicated a continuous increase in pedestal current, resulting in conditions consistent with destabilization of a peeling-ballooning mode. P^PED evolution was dominated by changes in the ne profile while Te stopped evolving after about 25% of the inter-ELM period, near the time of onset of density fluctuations observed by BES. However the Te^PED and ?Te varied with heating power. P^PED in higher Ip discharges grew mainly through ?p increases. In this case ?p was below the KBM limit predicted by the EPED model early in the inter-ELM period, although all cases were near the EPED predictions at the ELM. The evolution of ne and Te in higher Ip cases was consistent with the paleo-classical model predictions.

Osborne, T. H.; Groebner, R. J.; Smith, S. P.; Snyder, P. B.; Thomas, D. M.; Boedo, J. A.; Rhodes, T. L.; Stoschus, H.; Yan, Z.

2012-10-01

247

Effects of cutting time, stump height, parent tree characteristics, and harvest variables on development of bigleaf maple sprout clumps  

USGS Publications Warehouse

In order to determine the effects of stump height, year of cutting, parent-tree size, logging damage, and deer browsing on bigleaf maple (Acer macrophyllum) sprout clump development, maple trees were cut to two stump heights at three different times. Stump height had the greatest impact on sprout clump size. Two years after clearcutting, the sprout clump volume for short stumps was significantly less than that for tall stumps. The sprout clump volume, area, and number of sprouts were significantly less for trees cut 1 and 2 yr before harvest than for trees cut at harvest. Sprout clump size was positively correlated with parent tree stem diameter and stump volume, and negatively correlated with the percentage of bark removed during logging. Browsing had no significant impact on average clump size. Uncut trees produced sprout clumps at their base and epicormic branches along the length of their stems; thus their crown volume averaged four to five times that of cut trees. Cutting maple in clearcuts to low stumps may reduce maple competition with Douglas-fir regeneration and still maintain maple in the next stand.

Tappeiner, J. C., II; Zasada, J.; Maxwell, B.; Maxwell, B.

1996-01-01

248

Waveform characteristics of deep low-frequency earthquakes: time-series evolution based on the theory of the KM2O-Langevin equation  

NASA Astrophysics Data System (ADS)

Since the 1970s, deep low-frequency earthquakes (DLF) with depths ranging 20-40 km have been observed just beneath the Japan Island Arc. Almost all of these earthquakes are recognized up to now have had magnitudes less than 2.5, so that we have little information concerning DLF. Employing the theory of KM2O-Langevin equations, we develop a new method to represent the characteristics of the coda parts of DLF, and propose a new concept of `average dissipation spectrum'. The new averaging algorithm for the KM2O-Langevin matrix function was applied in the analysis of DLF (M: 1.0), which occurred in Akita prefecture on 2001 July 11, and we succeeded in separating the characteristics of the source vibration system and the source excitation process into the averaged dissipation term and the fluctuation term, respectively. The gaps between the arrival times of the fluctuation term's peaks at three stations near the epicentre are slightly different than the gaps between the S-wave arrival times. Assuming a homogenous crust structure with an S-wave velocity of 4.3 km s-1 and assuming the depth of the second source to be the same as that of the hypocentre, the second source lies about 1.5 km, N 56°E of the hypocentre. We estimate the common characteristics of this DLF successfully by using the `average dissipation spectrum', which is made up of typical frequencies, ?k, attenuation factors, Qk and amplitude factors, Ak. The common elements of (?k~ 1.5, Qk~-0.3) and (?k~ 3.25, Qk~-0.45) among all stations indicate the characteristics of the source dynamics of the Akita DLF. The major parts of the coda waves of DLF satisfy the stationary property, and the causality values for the linear and odd-degree non-linear transformations are relatively higher than those for the even-degree non-linear transformations. These characteristics are quite different from the characteristics of tectonic earthquakes. This quantitative property is common among all DLF.

Takeo, Minoru; Ueda, Hiroko; Okabe, Yasunori; Matsuura, Masaya

2006-04-01

249

A SPITZER SURVEY OF PROTOPLANETARY DISK DUST IN THE YOUNG SERPENS CLOUD: HOW DO DUST CHARACTERISTICS EVOLVE WITH TIME?  

SciTech Connect

We present Spitzer InfraRed Spectrograph (IRS) mid-infrared (5-35 {mu}m) spectra of a complete flux-limited sample ({>=}3 mJy at 8 {mu}m) of young stellar object (YSO) candidates selected on the basis of their infrared colors in the Serpens Molecular Cloud. Spectra of 147 sources are presented and classified. Background stars (with slope consistent with a reddened stellar spectrum and silicate features in absorption), galaxies (with redshifted polycyclic aromatic hydrocarbon (PAH) features), and a planetary nebula (with high ionization lines) amount to 22% of contamination in this sample, leaving 115 true YSOs. Sources with rising spectra and ice absorption features, classified as embedded Stage I protostars, amount to 18% of the sample. The remaining 82% (94) of the disk sources are analyzed in terms of spectral energy distribution shapes, PAHs, and silicate features. The presence, strength, and shape of these silicate features are used to infer disk properties for these systems. About 8% of the disks have 30/13 {mu}m flux ratios consistent with cold disks with inner holes or gaps, and 3% of the disks show PAH emission. Comparison with models indicates that dust grains in the surface of these disks have sizes of at least a few {mu}m. The 20 {mu}m silicate feature is sometimes seen in the absence of the 10 {mu}m feature, which may be indicative of very small holes in these disks. No significant difference is found in the distribution of silicate feature shapes and strengths between sources in clusters and in the field. Moreover, the results in Serpens are compared with other well-studied samples: the c2d IRS sample distributed over five clouds and a large sample of disks in the Taurus star-forming region. The remarkably similar distributions of silicate feature characteristics in samples with different environment and median ages-if significant-imply that the dust population in the disk surface results from an equilibrium between dust growth and destructive collision processes that are maintained over a few million years for any YSO population irrespective of environment.

Oliveira, Isa; Van Dishoeck, Ewine F.; Lahuis, Fred [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Pontoppidan, Klaus M. [California Institute of Technology, Division for Geological and Planetary Sciences, MS 150-21, Pasadena, CA 91125 (United States); MerIn, Bruno [Herschel Science Center, European Space Agency (ESA), P.O. Box 78, 28691 Villanueva de la Canada (Madrid) (Spain); Geers, Vincent C. [University of Toronto, 50 St. George St., Toronto, ON M5R 2W9 (Canada); Joergensen, Jes K. [Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Oester Voldgade 5-7, DK-1350 Copenhagen (Denmark); Olofsson, Johan; Augereau, Jean-Charles [Laboratoire d'Astrophysique de Grenoble, Universite Joseph Fourier, CNRS, UMR 5571, Grenoble (France); Brown, Joanna M., E-mail: oliveira@strw.leidenuniv.n [Max-Planck Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany)

2010-05-01

250

Variations of soil profile characteristics due to varying time spans since ice retreat in the inner Nordfjord, western Norway  

NASA Astrophysics Data System (ADS)

In the Erdalen and Bødalen drainage basins located in the inner Nordfjord in western Norway the soils have been formed after deglaciation. The climate in the upper valley part is sub-arctic oceanic with an annual areal precipitation of ca 1500 mm. The lithology in Erdalen and Bødalen consists of Precambrian granitic orthogneisses on which Leptosols and Regosols are the most common soils. Parts of the valleys were affected by the Little Ice Age glacier advance with the maximum glacier extent around 1750 BP. In this study five sites on moraine and colluvium materials were selected to examine the main soil properties of the most representative soils found in the region. The objective was to assess if soil profile characteristics and pattern of fallout radionuclides (FRN's) and environmental radionuclides (ERN's) are affected by different stages of ice retreat. Soil profiles were sampled at 5 cm depth interval increments until 20 cm depth. The Leptosols on the moraines are shallow, poorly developed and vegetated with moss and small birches. The two selected profiles show different radionuclide activities and grain size distribution. At P2 profile where ice retreated earlier (ca., 1767) depth profile activities of FR?s are more homogenous than in P1 that became ice-free since ca. 1930. The sampled soils on the colluviums outside the LIA glacier limit became ice free during the Preboral. The Regosols present better developed profiles, thicker organic horizons and are fully covered by grasses. Activity of 137Cs and 210Pbex concentrate at the topsoil and decrease sharply with depth. The grain size distribution of these soils also reflects the difference in geomorphic processes that have affected the colluvium sites. Lower activities of FR?s in soils on the moraines are related to the predominant sand material that has less capacity to fix the radionuclides. Lower 40K activities in Erdalen as compared to Bødalen are likely related to soil mineralogical composition. All profiles show disequilibrium in the uranium and thorium series. These results indicate differences in soil development that are consistent with the age of ice retreat. In addition, the pattern distribution of 137Cs and 210Pbexactivities differs in the soils related to the LIA glacier limits in the drainage basins.

Navas, Ana; Laute, Katja; Beylich, Achim A.; Gaspar, Leticia

2013-04-01

251

Space-time characteristics of the turbulent flow energy in a viscoelastic medium using noninvasive passive imaging  

NASA Astrophysics Data System (ADS)

This report describes the technology required for noninvasive passive imaging of the turbulent flow energy of space-time signals in a viscoelastic medium. The need for such technology emerges from the field of biomedicine, where low cost noninvasive techniques are necessary to accurately diagnose heart disease. A sensor that can detect extremely low energy levels, such as those encountered in a stenosed artery, is investigated. An experiment that consists of a urethane solid containing a partially blocked embedded surgical tube is described. Measurements of turbulence-induced energy levels are included in both the spatial-frequency domain and the wavenumber-frequency domain. Modeling of continuous sources using two different beamformers is addressed. Also presented are recommendations for future studies.

Owsley, Norman L.; Ahmed, Mohamed H.; Hull, Andrew J.; Kassal, James

1995-03-01

252

Influence of reaction time and temperature on product formation and characteristics associated with the hydrothermal carbonization of cellulose.  

PubMed

Studies have demonstrated that hydrothermal carbonization of biomass and waste streams results in the formation of beneficial materials/resources with minimal greenhouse gas production. Data necessary to understand how critical process conditions influence carbonization mechanisms, product formation, and associated environmental implications are currently lacking. The purpose of this work is to hydrothermally carbonize cellulose at different temperatures and to systematically sample over a 96-h period to determine how changes in reaction temperature influence product evolution. Understanding cellulose carbonization will provide insight to carbonization of cellulosic biomass and waste materials. Results from batch experiments indicate that the majority of cellulose conversion occurs between the first 0.5-4h, and faster conversion occurs at higher temperatures. Data collected over time suggest cellulose solubilization occurs prior to conversion. The composition of solids recovered after 96h is similar at all temperatures, consisting primarily of sp(2) carbons (furanic and aromatic groups) and alkyl groups. PMID:23612178

Lu, Xiaowei; Pellechia, Perry J; Flora, Joseph R V; Berge, Nicole D

2013-04-01

253

Global characteristics of the correlation and time lag between solar and ionospheric parameters in the 27-day period  

NASA Astrophysics Data System (ADS)

The 27-day variations of topside ionosphere are investigated using the in situ electron density measurements from the CHAMP planar Langmuir probe and GRACE K-band ranging system. As the two satellite systems orbit at the altitudes of ˜370 km and ˜480 km, respectively, the satellite data sets are greatly valuable for examining the electron density variations in the vicinity of F2-peak. In a 27-day period, the electron density measurements from the satellites are in good agreements with the solar flux, except during the solar minimum period. The time delays are mostly 1-2 day and represent the hemispherical asymmetry. The globally-estimated spatial patterns of the correlation between solar flux and in situ satellite measurements show poor correlations in the (magnetic) equatorial region, which are not found from the ground measurements of vertically-integrated electron content. We suggest that the most plausible cause for the poor correlation is the vertical movement of ionization due to atmospheric dynamic process that is not controlled by the solar extreme ultraviolet radiation.

Lee, Choon-Ki; Han, Shin-Chan; Bilitza, Dieter; Seo, Ki-Weon

2012-03-01

254

Physicochemical analysis from real-time imaging of liposome tubulation reveals the characteristics of individual F-BAR domain proteins.  

PubMed

The Fer-CIP4 homology-BAR (F-BAR) domain, which was identified as a biological membrane-deforming module, has been reported to transform lipid bilayer membranes into tubules. However, details of the tubulation process, the mechanism, and the properties of the generated tubules remain unknown. Here, we successfully monitored the entire process of tubulation and the behavior of elongated tubules caused by four different F-BAR domain family proteins (FBP17, CIP4, PSTPIP1, and Pacsin2) using direct real-time imaging of giant unilamellar liposomes with dark-field optical microscopy. FBP17 and CIP4 develop many protrusions simultaneously over the entire surface of individual liposomes, whereas PSTPIP1 and Pacsin2 develop only a few protrusions from a narrow restricted part of the surface of individual liposomes. Tubules formed by FBP17 or CIP4 have higher bending rigidities than those formed by PSTPIP1 or Pacsin2. The results provide striking evidence that these four F-BAR domain family proteins should be classified into two groups: one group of FBP17 and CIP4 and another group of PSTPIP1 and Pacsin2. This classification is consistent with the phylogenetic proximity among these proteins and suggests that the nature of the respective tubulation is associated with biological function. These findings aid in the quantitative assessment with respect to manipulating the morphology of lipid bilayers using membrane-deforming proteins. PMID:23199228

Tanaka-Takiguchi, Yohko; Itoh, Toshiki; Tsujita, Kazuya; Yamada, Shunsuke; Yanagisawa, Miho; Fujiwara, Kei; Yamamoto, Akihisa; Ichikawa, Masatoshi; Takiguchi, Kingo

2012-12-13

255

Influence of the laser parameters on the space and time characteristics of an aluminum laser-induced plasma  

NASA Astrophysics Data System (ADS)

In this work, an aluminum laser plasma produced in ambient air at atmospheric pressure by laser pulses at a fluence of 10 J/cm2 is characterized by time- and space-resolved measurements of electron density and temperature. Varying the laser pulse duration from 6 ns to 80 fs and the laser wavelength from ultraviolet to infrared only slightly influences the plasma properties. The temperature exhibits a slight decrease both at the plasma edge and close to the target surface. The electron density is found to be spatially homogeneous in the ablation plume during the first microsecond. Finally, the plasma expansion is in good agreement with the Sedov's model during the first 500 ns and it becomes subsonic, with respect to the velocity of sound in air, typically 1 ?s after the plasma creation. The physical interpretation of the experimental results is also discussed to the light of a one-dimensional fluid model which provides a good qualitative agreement with measurements.

Barthélemy, O.; Margot, J.; Chaker, M.; Sabsabi, M.; Vidal, F.; Johnston, T. W.; Laville, S.; Le Drogoff, B.

2005-08-01

256

Effect of gamma irradiation and storage time on microbial growth and physicochemical characteristics of pumpkin (Cucurbita Moschata Duchesne ex Poiret) puree.  

PubMed

The effect of gamma irradiation (0-2?kGy) and storage time (0-28 days) on microbial growth and physicochemical characteristics of a packed pumpkin puree was studied. For that purpose, a factorial design was applied. The puree contained potassium sorbate, glucose and vanillin was stored at 25?. Gamma irradiation diminished and storage time increased microbial growth. A synergistic effect between both variables on microbial growth was observed. Storage time decreased pH and color of purees. Sorbate content decreased with storage time and gamma irradiation. Mathematical models of microbial growth generated by the factorial design allowed estimating that a puree absorbing 1.63?kGy would have a shelf-life of 4 days. In order to improve this time, some changes in the applied hurdles were assayed. These included a thermal treatment before irradiation, a reduction of irradiation dose to 0.75?kGy and a decrease in storage temperature at 20?. As a result, the shelf-life of purees increased to 28 days. PMID:23733817

Gliemmo, María F; Latorre, María E; Narvaiz, Patricia; Campos, Carmen A; Gerschenson, Lía N

2013-06-01

257

Characteristics of the Lower Thermosphere and Ionospheric D Region Deduced From High Time-Resolution Sporadic E-Layer Data During the Solar Eclipse of August 1, 2008  

NASA Astrophysics Data System (ADS)

The digital ionosonde at Sodankylä Geophysical Observatory, Finland, is performing continuous high time resolution soundings since the beginning of IPY in 2007. During the partial solar eclipse which occurred on first of August, 2008, a stable sporadic E layer was observed with the ionosonde. Using the time development of the recorded echo power of the sporadic E trace at different frequencies as a constraint, we analyse the underlying lower thermospheric and ionospheric D-region characteristics, by applying a detailed coupled ion and neutral chemistry model SIC (Sodankyla Ion Chemistry model), together with modeling of the radio wave propagation and absorption. Use of a simplified ion chemistry model is compared with the use of the SIC model. While the expected effect of the solar eclipse on E-layer critical frequency cannot be seen due to the existence of the sporadic E layer, ionisation in the D-region is consistent with the variation of solar radiation during the eclipse.

Enell, C.; Turunen, E.; Kero, A.; Ulich, T.; Tapaninen, O.; Kaaretkoski, H.; Karppinen, T.

2008-12-01

258

Time-resolved spectral characteristics of external-cavity quantum cascade lasers and their application to stand-off detection of explosives  

NASA Astrophysics Data System (ADS)

We present the time-resolved spectral analysis of the settling process in a pulsed external-cavity quantum-cascade laser (EC-QC laser) emitting in the wavelength range around 7.4 ?m. Due to mode competition between the two cavities formed by the laser-chip on one hand and the external-cavity on the other hand, a time-dependent spectral emission on a ns time-scale can be observed. Depending on the spectral characteristic of the external cavity with respect to the chip gain curve time-delays of the external cavity emission of 15-35 ns within the 100 ns drive pulse can be observed. Regarding the application, we discuss the results in the context of using the EC-QC laser system together with a high-performance IR-camera for stand-off detection of surface-contaminations with explosives such as TNT. The detected densities can be as small as 10 ?g/cm2 corresponding to traces left by a fingerprint.

Hinkov, B.; Fuchs, F.; Yang, Q. K.; Kaster, J. M.; Bronner, W.; Aidam, R.; Köhler, K.; Wagner, J.

2010-08-01

259

Characteristic Time Scales of Transport Processes for Chemotactic Bacteria in Groundwater: Analysis of Pore-scale to Field-scale Experimental Data  

NASA Astrophysics Data System (ADS)

Many processes contribute to the transport of microorganisms in groundwater environments. One process of interest is chemotaxis, whereby motile bacteria are able to detect and swim toward increasing concentrations of industrial hydrocarbons that they perceive as food sources. By enabling bacteria to migrate to the sources of pollutants that they degrade, chemotaxis has the potential to enhance bioremediation efforts, especially in less permeable zones where contamination may persist. To determine the field conditions under which chemotaxis might be exploited in a bioremediation scheme requires an understanding of the characteristic time scales in the system. We defined a dimensionless chemotaxis number that compares the time over which a bacterial population is exposed to a chemical gradient to the time required for a bacterial population to migrate a significant distance in response to a chemical gradient. The exposure time and the response time are dependent upon the experimental conditions and properties of the bacteria and chemical attractant. Experimental data was analyzed for a range of groundwater flow rates over a wide scope of experimental systems including a single-pore with NAPL source, a microfluidic channel with and without a porous matrix, a laboratory column, a bench-scale microcosm and a field-scale study. Chemical gradients were created transverse to the flow direction. Distributions of chemotactic and nonchemotactic bacteria were compared to determine the extent of migration due to chemotaxis. Under some conditions at higher flow rates, the effect of chemotaxis was diminished to the point of not being detected. The goal of the study was to determine a critical value for the dimensionless chemotaxis number (which is independent of scale) that can be used as a design criterion to ascertain a priori the conditions under which a chemotactic response will impact bacterial transport relative to other processes such as advection and dispersion.

Ford, R. M.

2010-12-01

260

Simulation of vegetation, soil characteristics, and topography effects on soil water distribution and streamflow timing over a semi-arid mountain catchment  

NASA Astrophysics Data System (ADS)

Soil water (? , m3m-3) and soil characteristics act as intermediaries, along with plants and climate, modifying and modulating streamflow timing and quantity-the majority in the intermountain US west resulting from spring-melt events of accumulated winter snow. The antecedent soil water conditions also predispose different patterns and dynamic responses, especially in semiarid, mountain regions. The context of soil water, analyzed using modeling, is necessary to describe the processes of soil water dynamics. In this research, two years of neutron probe soil water data from a small, semiarid mountain catchment were evaluated using a vertical flow, combined snowmelt-soil water, capacitance-parameter model with available snowmelt data and climate data as driving inputs. Model parameters were vegetation characteristics and soil properties. Results at the point scale show good fit at many locations while a few have poor simulation results at depth. The discrepancies are hypothesized to be due to lack of understanding of parameters such as rooting depth of trees; heterogeneity of parameters within the soil layers; using capacitance parameters that treat some variables as constants; exclusion of lateral flow processes that must occur in some locations due to basin geometry and nature of soil-fractured bedrock interface; and rising water table effects that can be seen in the gleying of clayey soils near drainage lines. Driving parameters were then distributed over the 0.36 km2 catchment using the regional 10 m DEM, soil maps, remotely sensed color-infrared imagery, and the spatiotemporal distributions of soil water from previous research. The model was run discretely at each pixel. Results matched point data simulations well. Simulated throughflow, totaled over the watershed, compared well with weir measured streamflow in timing and quantity indicating accurate representation of parameters over the watershed, proper calibration, and well described processes.

Grant, L. E.; Seyfried, M. S.; Marks, D.; Winstral, A.

2004-12-01

261

Estimating forest structural characteristics using the airborne LiDAR scanning system and a near-real time profiling laser system  

NASA Astrophysics Data System (ADS)

LiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatially-explicit mapping of forest characteristics, such as canopy height and Leaf Area Index. However, many factors, such as large data volume and high costs for data acquisition, precludes the operational and practical use of most currently available LiDARs for frequent and large-scale mapping. At the same time, a growing need is arising for real-time remote sensing platforms, e.g., to provide timely information for urgent applications. This study aims to develop an airborne profiling LiDAR system, featured with on-the-fly data processing, for near real- or real-time forest inventory. The development of such a system involves implementing the on-board data processing and analysis as well as building useful regression-based models to relate LiDAR measurements with forest biophysical parameters. This work established a paradigm for an on-the-fly airborne profiling LiDAR system to inventory regional forest resources in real- or near real-time. The system was developed based on an existing portable airborne laser system (PALS) that has been previously assembled at NASA by Dr. Ross Nelson. Key issues in automating PALS as an on-the-fly system were addressed, including the design of an archetype for the system workflow, the development of efficient and robust algorithms for automatic data processing and analysis, the development of effective regression models to predict forest biophysical parameters from LiDAR measurements, and the implementation of an integrated software package to incorporate all the above development. This work exploited the untouched potential of airborne laser profilers for real-time forest inventory, and therefore, documented an initial step toward developing airborne-laser-based, on-the-fly, real-time, forest inventory systems. Results from this work demonstrated the utility and effectiveness of airborne scanning or profiling laser systems for remotely measuring various forest structural attributes at a range of scales, i.e., from individual tree, plot, stand and up to regional levels. The system not only provides a regional assessment tool, one that can be used to repeatedly, remotely measure hundreds or thousands of square kilometers with little/no analyst interaction or interpretation, but also serves as a paradigm for future efforts in building more advanced airborne laser systems such as real-time laser scanners.

Zhao, Kaiguang

262

Implementation of Near Real-Time Methods Using Surface Waves to Determine Earthquake Source Characteristics at the National Earthquake Information Center  

NASA Astrophysics Data System (ADS)

We discuss the implementation of two near real-time methods for determining earthquake source characteristics using long-period surface waves at the US Geological Survey's National Earthquake Information Center (USGS/NEIC). Long-period (60 to 300 s) seismic waveforms are well suited for this purpose because they can be well modeled using simple propagation models and are less sensitive to source complexity than short period (1 s) waves that are commonly used for earthquake monitoring. A prototype system for Surface wave Location and Association in Quasi Real time (SLAQR) that employs very long period (> 60 s) vertical-component surface waves has been implemented in test mode using data from the Global Seismographic Network (GSN). SLAQR continuously back-projects waveform envelopes on a global grid using surface wave dispersion relations. Preliminary results show that this method, as currently in operation at the NEIC, can consistently locate global earthquakes down to a magnitude 5.5. The magnitude determination, which is based on a simple empirical relationship, is generally accurate to within 0.2 magnitude units. More importantly, SLAQR can provide reliable locations and magnitudes for very large earthquakes, such as the 2004/2005 Sumatra events, within 30-40 minutes of their origin time. Furthermore, since the magnitude calculation is based on long period data, magnitudes for slow earthquakes such as some ridge and tsunami earthquakes are not underestimated as commonly occurs in shorter period analysis. Future development will focus on a reliable triggering algorithm for automated event detection and the continuous calculation of moment tensors and earthquake depths from the spectral amplitude and phase measurements already produced by the system. A fully automatic system to determine centroid moment tensors using three component surface waves with periods between 150-300 s is also running at the NEIC. Two versions are currently operational: one in a research/evaluation mode and another fully incorporated into the NEIC Hydra system. New improvements in the area of reliability assessment are currently being tested. Future work will investigate the finite fault information contained in the centroid time and centroid location parameters, how to incorporate a priori knowledge of the fault orientation, and the use of noise characteristics in the automatic selection of channels.

Polet, J.; Thio, H. K.; Earle, P.

2008-12-01

263

Experiments on hypersonic boundary layer transition on blunt cones with acoustic-absorption coating  

NASA Astrophysics Data System (ADS)

The laminar-turbulent transition is studied experimentally on a cone with an acoustic-absorption coating and with different nose bluntness in a high-speed flow. The acoustic-absorption coating is a felt metal sheet with a random microstructure. Experiments were carried out on a 1-meter length 7 degree cone at free-stream Mach number M = 8 and zero angle of attack. Locations of the laminar-turbulent transition are detected using heat flux distributions registered by calorimeter sensors. In addition, boundary layer pulsations are measured by means of ultrafast heat flux sensors. It is shown that the laminar-turbulent transition is caused by the second-mode instability, and the laminar run extends as the bluntness is increased. The porous coating effectively suppresses this instability for all tested bluntness values and 1.3-1.85 times extends the laminar run.

Shiplyuk, A.; Lukashevich, S.; Bountin, D.; Maslov, A.; Knaus, H.

2012-01-01

264

In-silico experiments on characteristic time scale at a shear-free gas-liquid interface in fully developed turbulence  

NASA Astrophysics Data System (ADS)

The purpose of this study is to model scalar transfer mechanisms in a fully developed turbulence for accurate predictions of the turbulent scalar flux across a shear-free gas-liquid interface. The concept of the surface-renewal approximation (Dankwerts, 1951) is introduced in this study to establish the predictive models for the interfacial scalar flux. Turbulent flow realizations obtained by a direct numerical simulation technique are employed to prepare details of three-dimensional information on turbulence in the region very close to the interface. Two characteristic time scales at the interface have been examined for exact prediction of the scalar transfer flux. One is the time scale which is reciprocal of the root-mean-square surface divergence, T? = langle??rangle-1/2, where ? is the surface divergence. The other time scale to be examined is TS = ?/V, where ? is the zero-correlation length of the surface divergence as the interfacial length scale, and V is the root-mean-square velocity fluctuation in the streamwise direction as the interfacial velocity scale. The results of this study suggests that T? is slightly unsatisfactory to correlate the turbulent scalar flux at the gas-liquid interface based on the surface-renewal approximation. It is also found that the proportionality constant appear to be 0.19, which is different with that observed in the laboratory experiments, 0.34 (Komori, Murakami, & Ueda, 1989). It is concluded that the time scale, T?, is considered a different kind of the time scale observed in the laboratory experiments. On the other hand, the present in-silico experiments indicate that Ts predicts the turbulent scalar flux based on the surface-renewal approximation in a satisfactory manner. It is also elucidated that the proportionality constant for Ts is approximately 0.36, which is very close to that found by the laboratory experiments. This fact shows that the time scale Ts appears to be essentially the same as the time scale the laboratory experiments observed.

Nagaosa, Ryuichi; Handler, Robert A.

2011-12-01

265

A statistically significant long term characteristic time-scale of test size variation of Calcareous Trochospiral Benthic Foraminifera (CTBF) during the past 120 m.y.  

NASA Astrophysics Data System (ADS)

Geo-marine records are faithful recorders of the earth's evolutionary history and hence are most suitable for identifying long-term cyclic patterns. Although a remarkable synchronism among Calcareous Trochospiral Benthic Foraminifera (CTBF) test size variation, ocean productivity, dissolved oxygen and global climate exists, global ``geospectroscopy'' is essential for understanding the wider ramification of significant physical linkages of the various terrestrial and extra-terrestrial processes. Earlier claims of a quasi-periodicity of 26-36 m.y. in various geo-bio-ocean-atmospheric records sparked a major controversy. Here, we examine spectral characteristics of the latest available time series representing fluctuations in test size of CTBF for the past 120 m.y. using the Multi-Taper Method (MTM) and Maximum Entropy Method (MEM) of spectral analyses. The analyses of test size variations of CTBF time series reveal, hitherto unidentified, a statistically significant and stable harmonic component of 35 +/- 5 m.y. against a robust ``red background noise''. Further, wavelet spectral analysis of this record exhibits a strong stationary power in the above frequency band suggesting temporal persistence of spectral peak through the entire evolutionary period. This finding renders credible support to the concept of cyclic geo-marine processes and will provide stimulus for further quantitative research into the coupling of marine geo-bio-chemical cycles.

Tiwari, R. K.; Rao, K. N. N.

2003-03-01

266

Comparison of characteristic and Gutenberg-Richter models for time-dependent M ? 7.9 earthquake probability in the Nankai-Tokai subduction zone, Japan  

NASA Astrophysics Data System (ADS)

Earthquake forecasts are usually underinformed, and can be plagued by uncertainty in terms of the most appropriate model, and parameter values used in that model. In this paper, we explore the application of two different models to the same seismogenic area. The first is a renewal model based on the characteristic earthquake hypothesis that uses historical/palaeoseismic recurrence times, and fixed rupture geometries. The hazard rate is modified by the Coulomb static stress change caused by nearby earthquakes that occurred since the latest characteristic earthquake. The second model is a very simple earthquake simulator based on plate-motion, or fault-slip rates and adoption of a Gutenberg-Richter magnitude-frequency distribution. This information is commonly available even if historical and palaeoseismic recurrence data are lacking. The intention is to develop and assess a simulator that has a very limited parameter set that could be used to calculate earthquake rates in settings that are not as rich with observations of large-earthquake recurrence behaviour as the Nankai trough. We find that the use of convergence rate as a primary constraint allows the simulator to replicate much of the spatial distribution of observed segmented rupture rates along the Nankai, Tonankai and Tokai subduction zones. Although we note rate differences between the two forecast methods in the Tokai zone, we also see enough similarities between simulations and observations to suggest that very simple earthquake rupture simulations based on empirical data and fundamental earthquake laws could be useful forecast tools in information-poor settings.

Parsons, Tom; Console, Rodolfo; Falcone, Giuseppe; Murru, Maura; Yamashina, Ken'ichiro

2012-09-01

267

Characteristics of individual rain events and its dependency on the minimum inter-event time in a dry desert area in north China  

NASA Astrophysics Data System (ADS)

The rain event characteristics was analysed using a pluviograph record of 2008 from an arid desert area of Shapotou in the Tengger Desert, China. Changing the minimum inter-event time (MIT) from 30 min to 24 h alters the number of rain events from 72 to 21. The mean rain rate declines from 0.85 mm h-1 to 0.4 mm h-1, and the geometric mean event duration rises from 0.64 h to 5.04 h. The number of rain events, the mean rain rate, and the geometric mean event duration differed under different criteria of individual rain depth (e.g., 0.1, 0.5, 1.0, 5.0 mm), except that for an individual rain depth of 0.5, 1.0, and 5.0 mm, the features (the number of rain events, the mean rain rate, and the geometric mean event duration) mentioned above are identical for MIT=2 and 3 h. Therefore, there is no need for further identification to set MIT at two or three hours in this specific arid desert area. This wide variation in the properties of rain events indicates that more attention needs to be paid to the selection and reporting of event criteria in studies that adopt event-based data analysis. The selection of a MIT criterion is shown to involve a compromise between the independence of widely-spaced events and their increasingly variable intra-event characteristics (Dunkerley, Hydrological Processes, 2008, 22(26): 5024-5036).

Wang, X.

2009-04-01

268

Characteristics of repair tissue in second-look and third-look biopsies from patients treated with engineered cartilage: relationship to symptomatology and time after implantation  

PubMed Central

Introduction The present study established characteristics of tissue regrowth in patients suffering knee lesions treated with grafts of autologous chondrocytes grown on three-dimensional hyaluronic acid biomaterials. Methods This multicentred study involved a second-look arthroscopy/biopsy, 5 to 33 months post implant (n = 63). Seven patients allowed a third-look biopsy, three of which were performed 18 months post implant. Characteristics of tissues were histologically and histochemically evaluated. The remaining bone stubs were evaluated for cartilage/bone integration. For data analysis, biopsies were further divided into those obtained from postoperative symptomatic patients (n = 41) or from asymptomatic patients (n = 22). Results The percentage of hyaline regenerated tissues was significantly greater in biopsies obtained after, versus within, 18 months of implantation. Differences were also observed between symptomatic and asymptomatic patients: reparative tissues taken from symptomatic patients 18 months after grafting were mainly fibrocartilage or mixed (hyaline–fibrocartilage) tissue, while tissues taken from asymptomatic patients were hyaline cartilage in 83% of biopsies. In a small group of asymptomatic patients (n = 3), second-look and third-look biopsies taken 18 months after surgery confirmed maturation of the newly formed tissue over time. Cartilage maturation occurred from the inner regions of the graft, in contact with subchondral bone, towards the periphery of the implant. Conclusions The study indicates that, in asymptomatic patients after chondrocyte implantation, regenerated tissue undergoes a process of maturation that in the majority of cases takes longer than 18 months for completion and leads to hyaline tissue and not fibrous cartilage. Persistence of symptoms might reflect the presence of a nonhyaline cartilage repair tissue.

Brun, Paola; Dickinson, Sally C; Zavan, Barbara; Cortivo, Roberta; Hollander, Anthony P; Abatangelo, Giovanni

2008-01-01

269

The physiological response, time-motion characteristics and reproducibility of various speed endurance drills in elite youth soccer players: small sided games vs generic running.  

PubMed

The aim of the study was to quantify the physiological responses, time-motion characteristics and reproducibility of various speed endurance production (SEP) and speed endurance maintenance (SEM) drills. Twenty-one elite male youth soccer players completed four drills: (1) SEP 1 v 1 small sided game, (2) SEP running drill, (3) SEM 2 v 2 small sided game and (4) SEM running drill. The SEP drills consisted of eight bouts of 30 s with 120 s recovery (1:4 exercise to rest ratio) whilst SEM drills encompassed eight bouts of 60 s with 60 s recovery (1:1 exercise to rest ratio). Heart rate response, blood lactate concentration, rating of perceived exertion and time-motion characteristics were recorded for each drill. The SEP and SEM running drills elicited greater (P<0.05) heart rate responses, blood lactate concentrations and subjective ratings of perceived exertion than the equivalent small sided games (ES: 1.1-1.4 & 1.0-3.2). Players covered less (P<0.01) total distance, high-, very high-speed running and sprint distance in the SEP and SEM small sided game's compared to the equivalent running drills (ES: 6.0-22.1 & 3.0-18.4). Greater distances (P<0.01) were covered in high and maximum acceleration/deceleration bands during the SEP and SEM small sided game's compared to the equivalent running drills (ES: 2.6-4.6 and 2.3-4.8). Small-moderate test-retest variability was observed for heart rate response (CV: 0.9-1.9%), ratings of perceived exertion (CV: 2.9-5.7%) and blood lactate concentration (CV: 9.9-14.4%); Moderate-large test-retest variability was observed for high-intensity running parameters (CV: >11.3%) and the majority of acceleration/deceleration distances (CV: >9.8%) for all small sided games and running drills. The data demonstrate the differential response of SEP and SEM training for taxing various energy systems and the superior acceleration/deceleration profiles of small sided games compared to generic running drills. PMID:24159151

Ade, J; Harley, J; Bradley, P

2013-11-01

270

Step-changes in the physical, chemical and biological characteristics of the Gulf of Maine, as documented by the GNATS time series  

USGS Publications Warehouse

We identify step-changes in the physical, chemical and biological characteristics of the Gulf of Maine (GoM) using the Gulf of Maine North Atlantic Time Series (GNATS), a series of oceanographic measurements obtained between September 1998 and December 2010 along a transect in the GoM running from Portland, ME, to Yarmouth, NS. GNATS sampled a period of extremes in precipitation and river discharge (4 of the 8 wettest years of the last century occurred between 2005 and 2010). Coincident with increased precipitation, we observed the following shifts: (1) decreased salinity and density within the surface waters of the western GoM; (2) both reduced temperature and vertical temperature gradients in the upper 50 m; (3) increased colored dissolved organic matter (CDOM) concentrations and particle scattering in the western GoM; (4) increased concentrations of nitrate and phosphate across all but the eastern GoM; (5) increased silicate, particularly in the western GoM, with a sharp increase in the ratio of silicate to dissolved inorganic nitrogen; (6) sharply decreased carbon fixation by phytoplankton; (7) moderately decreased chlorophyll, particulate organic carbon (POC) and particulate inorganic carbon (PIC) in the central GoM and (8) decreased POC- and PIC-specific growth rates. Gulf-wide anomaly analyses suggest that (1) the surface density changes were predominantly driven by temperature, (2) dissolved nutrients, as well as POC/PON, varied in Redfield ratios and (3) anomalies for salinity, density, CDOM, particle backscattering and silicate were significantly correlated with river discharge. Precipitation and river discharge appear to be playing a critical role in controlling the long-term productivity of the Gulf of Maine by supplying CDOM and detrital material, which ultimately competes with phytoplankton for light absorption.

Balch, William M.; Drapeau, D. T.; Bowler, B. C.; Huntington, Thomas G.

2012-01-01

271

Wavelet analysis of paleomagnetic data: 1. Characteristic average times (5 10 kyr) of variations in the geomagnetic field during and immediately before and after the Early Jaramillo reversal (Western Turkmenistan)  

NASA Astrophysics Data System (ADS)

Joint wavelet analysis of complete and downsampled series of paleomagnetic and petromagnetic characteristics of rocks in the Matuyama-Jaramillo transitional zone in the Adzhidere section is used to extract paleomagnetic data whose variations are associated with the geomagnetic field alone and data correlating with variations in petromagnetic parameters. It supposed that this correlation can be caused by an external factor affecting weak variations in the magnetic field and climatic changes reflected in the composition and amount of the ferromagnetic fraction in rocks. Preliminary data are obtained for the characteristic times of field variations at the time of accumulation of rocks in the transitional zone.

Gurarii, G. Z.; Aleksyutin, M. V.; Ataev, N.

2007-10-01

272

Comparison of Performance Characteristics of Three Real-Time Reverse Transcription-PCR Test Systems for Detection and Quantification of Hepatitis C Virus?  

PubMed Central

We evaluated the performance characteristics of three real-time reverse transcription-PCR test systems for detection and quantification of hepatitis C virus (HCV) and performed a direct comparison of the systems on the same clinical specimens. Commercial HCV panels (genotype 1b) were used to evaluate linear range, sensitivity, and precision. The Roche COBAS TaqMan HCV test for research use only (RUO) with samples processed on the MagNA Pure LC instrument (Roche RUO-MPLC) and Abbott analyte-specific reagents (ASR) with QIAGEN sample processing (Abbott ASR-Q) showed a sensitivity of 1.0 log10 IU/ml with a linear dynamic range of 1.0 to 7.0 log10 IU/ml. The Roche ASR in combination with the High Pure system (Roche ASR-HP) showed a sensitivity of 1.4 log10 IU/ml with a linear dynamic range of 2.0 to 7.0 log10 IU/ml. All of the systems showed acceptable reproducibility, the Abbott ASR-Q being the most reproducible of the three systems. Seventy-six clinical specimens (50 with detectable levels of HCV RNA and various titers and genotypes) were tested, and results were compared to those of the COBAS Amplicor HCV Monitor v2.0. Good correlation was obtained for the Roche RUO-MPLC and Abbott ASR-Q (R2 = 0.84 and R2 = 0.93, respectively), with better agreement for the Abbott ASR-Q. However, correlation (R2 = 0.79) and agreement were poor for Roche ASR-HP, with bias relative to concentration and genotype. Roche ASR-HP underestimated HCV RNA for genotypes 3 and 4 as much as 2.19 log10 IU/ml. Our study demonstrates that Roche RUO-MPLC and Abbott ASR-Q provided acceptable results and agreed sufficiently with the COBAS Amplicor HCV Monitor v2.0.

Sabato, M. Fernanda; Shiffman, Mitchell L.; Langley, Michael R.; Wilkinson, David S.; Ferreira-Gonzalez, Andrea

2007-01-01

273

Dependence of the time- and frequency-domain response of BCI injection probes on the common- mode characteristic impedance of the cable bundle  

Microsoft Academic Search

The common-mode characteristic impedance of a typical cable bundle has been suggested to be approximately 150 Ohms. However, standard test fixtures for BCI probes employ 50 Ohm coaxial ports. Here a representative injection probe (transformer) intended for bulk current injection applications is characterized experimentally in the frequency domain using a 2-port vector network analyzer and a standard (50 Ohm) test

James McLean; Robert Sutton

2010-01-01

274

Timing matters.  

PubMed

Cells are entities in space and time. Systems biology strives to understand their composition, structural organization as well as dynamic behavior under different conditions. Here, measures for dynamic properties such as characteristic times, time hierarchy and time-dependent response are reviewed. Using a number of examples from yeast and micro-organism systems biology, the importance of considering the timing in experimental and theoretical research is discussed. PMID:19941864

Klipp, Edda

2009-12-17

275

Estimating forest structural characteristics using the airborne LiDAR scanning system and a near-real time profiling laser system  

Microsoft Academic Search

LiDAR (Light Detection and Ranging) directly measures canopy vertical structures, and provides an effective remote sensing solution to accurate and spatially-explicit mapping of forest characteristics, such as canopy height and Leaf Area Index. However, many factors, such as large data volume and high costs for data acquisition, precludes the operational and practical use of most currently available LiDARs for frequent

Kaiguang Zhao

2008-01-01

276

Flower receptivity and fruit characteristics associated to time of pollination in the yellow passion fruit Passiflora edulis Sims f. flavicarpa Degener (Passifloraceae)  

Microsoft Academic Search

Flower receptivity during the period the flower is open was assessed with two histochemical tests, alpha-naphtil acetate and hydrogen peroxide, and with a controlled pollination test in a yellow passion fruit population, from midday to 17:00h, in two seasons, autumn and summer. The fruit obtained from the pollinated stigmas were assessed for four characteristics: weight, length, diameter and seed number.

Margarete Magalhães Souza; Telma N. Santana Pereira; Alexandre Pio Viana; Messias Gonzaga Pereira; Antônio Teixeira do Amaral Júnior; Hérika Chagas Madureira

2004-01-01

277

Depressive symptoms in the Netherlands 1975–1996: a theoretical framework and an empirical analysis of socio-demographic characteristics, gender differences and changes over time  

Microsoft Academic Search

This article examines the longitudinal trend of depressive symptoms in the Netherlands, using large-scale national data recorded over the period 1975-1996. Our analyses showed fluctuations in the overall longitudinal trend. On the basis of a general theoretical framework, we formulated hypotheses concerning which socio-demographic characteristics determine the likelihood of suffering from depressive symptoms and how these associations might have changed

Vivian Vivian Meertens; Peer Scheepers; Bert Tax

2003-01-01

278

Active play and screen time in US children aged 4 to 11 years in relation to sociodemographic and weight status characteristics: a nationally representative cross-sectional analysis  

Microsoft Academic Search

BACKGROUND: The high prevalence of childhood obesity underscores the importance of monitoring population trends in children's activity and screen time, and describing associations with child age, gender, race\\/ethnicity, and weight status. Our objective was to estimate the proportion of young children in the US who have low levels of active play or high levels of screen time, or who have

Sarah E Anderson; Christina D Economos; Aviva Must

2008-01-01

279

SPECIAL ISSUE DEVOTED TO MULTIPLE RADIATION SCATTERING IN RANDOM MEDIA: Time-domain diffuse optical tomography using analytic statistical characteristics of photon trajectories  

NASA Astrophysics Data System (ADS)

The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions.

Konovalov, Aleksandr B.; Vlasov, V. V.; Kalintsev, A. G.; Kravtsenyuk, Olga V.; Lyubimov, Vladimir V.

2006-11-01

280

Maximal force, force\\/time and activation\\/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at different ages  

Microsoft Academic Search

.   This study examined the force production characteristics, activation\\/coactivation and endurance capacity of the neck extension\\u000a and flexion muscles in healthy men (n=29) and women (n=28) divided into three age groups (18–26 years, 30–37 years and 45–55 years). Force and electromyography (EMG) measurements\\u000a were performed during the maximal voluntary isometric extension and flexion actions. This was followed by an endurance test\\u000a (ET; 60%

Heli Valkeinen; Jari Ylinen; Esko Mälkiä; Markku Alen; Keijo Häkkinen

2002-01-01

281

Do socioeconomic characteristics modify the short term association between air pollution and mortality? Evidence from a zonal time series in Hamilton, Canada  

PubMed Central

Study objective: To assess the short term association between air pollution and mortality in different zones of an industrial city. An intra-urban study design is used to test the hypothesis that socioeconomic characteristics modify the acute health effects of ambient air pollution exposure. Design: The City of Hamilton, Canada, was divided into five zones based on proximity to fixed site air pollution monitors. Within each zone, daily counts of non-trauma mortality and air pollution estimates were combined. Generalised linear models (GLMs) were used to test mortality associations with sulphur dioxide (SO2) and with particulate air pollution measured by the coefficient of haze (CoH). Main results: Increased mortality was associated with air pollution exposure in a citywide model and in intra-urban zones with lower socioeconomic characteristics. Low educational attainment and high manufacturing employment in the zones significantly and positively modified the acute mortality effects of air pollution exposure. Discussion: Three possible explanations are proposed for the observed effect modification by education and manufacturing: (1) those in manufacturing receive higher workplace exposures that combine with ambient exposures to produce larger health effects; (2) persons with lower education are less mobile and experience less exposure measurement error, which reduces bias toward the null; or (3) manufacturing and education proxy for many social variables representing material deprivation, and poor material conditions increase susceptibility to health risks from air pollution.

Jerrett, M; Burnett, R; Brook, J; Kanaroglou, P; Giovis, C; Finkelstein, N; Hutchison, B

2004-01-01

282

Characteristics of the m2000 automated sample preparation and multiplex real-time PCR system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae.  

PubMed

We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay. PMID:17202273

Marshall, R; Chernesky, M; Jang, D; Hook, E W; Cartwright, C P; Howell-Adams, B; Ho, S; Welk, J; Lai-Zhang, J; Brashear, J; Diedrich, B; Otis, K; Webb, E; Robinson, J; Yu, H

2007-01-03

283

Is it the grain size or the characteristic pore size that controls the induced polarization relaxation time of clean sands and sandstones?  

NASA Astrophysics Data System (ADS)

There is a wide range of evidence to suggest that permeability can be constrained through of induced polarization measurements. For clean sands and sandstones, current mechanistic models of induced polarization predict a relationship between the low-frequency time constant inferred from induced polarization measurements and the grain diameter. A number of observations do, however, disagree with this and indicate that the observed relaxation behavior is rather governed by the so-called dynamic pore radius ?. To test this hypothesis, we have developed a set of new scaling relationships, which allow the relaxation time to be computed from the pore size and the permeability to be computed from both the Cole-Cole time constant and the formation factor. Moreover, these new scaling relationships can be also used to predict the dependence of the Cole-Cole time constant as a function of the water saturation under unsaturated conditions. Comparative tests of the proposed new relationships with regard to various published experimental results for saturated clean sands and sandstones as well as for partially saturated clean sandstones, do indeed confirm that the dynamic pore radius ? is a much more reliable indicator of the observed relaxation behavior than grain-size-based models.

Revil, André; Koch, Kristof; Holliger, Klaus

2012-05-01

284

Slaughter Plant Location, USDA Quality Grade, External Fat Thickness, and Aging Time Effects on Sensory Characteristics of Beef Loin Strip Steak1  

Microsoft Academic Search

A boneless beef strip loin (IMPS #180) was fabricated from each of 320 carcasses to study the effects of slaughter plant location, quality grade, fat thickness, and aging time on beef tender- ness and palatability. Carcasses were selected for fat thickness (< .5 cm or ? .5 cm fat thickness) and USDA quality grade (Select or Low Choice) from two

M. F. Miller; C. R. Kerth; J. W. Wise; J. L. Lansdell; J. E. Stowell; C. B. Ramsey

2010-01-01

285

Impact of the type of anodic film formed and deposition time on the characteristics of porous anodic aluminium oxide films containing Ni metal  

Microsoft Academic Search

Porous anodic films containing nickel were prepared by AC electro-deposition. The porosity of the films was controlled by\\u000a using different working conditions (anodisation electrolyte, voltage, and time). Then nickel was electro-deposited using an\\u000a alternating voltage. The impact of the anodic film on the current density waveforms and the metal content can largely be explained\\u000a by the porosity differences, while changing

Gaël Zamora; Laurent Arurault; Peter Winterton; René Bes

2011-01-01

286

Speaker Characteristics  

Microsoft Academic Search

In this chapter, we give a brief introduction to speech-driven applications in order to motivate why it is desirable to automatically recognize particular speaker characteristics from speech. Starting from these applications,\\u000a we derive what kind of characteristics might be useful. After categorizing relevant speaker characteristics, we describe in more detail\\u000a language, accent, dialect, idiolect, and sociolect. Next, we briefly summarize

Tanja Schultz

2007-01-01

287

Clinical and electrophysiologic characteristics of sinoatrial entrance block evaluated by direct sinus node electrography: prevalence, relation to antegrade sinoatrial conduction time, and relevance to sinus node disease.  

PubMed

When AV conduction is normal, the absence of VA conduction is not abnormal. Analogous information about retrograde sinoatrial conduction is not available. Although the premature atrial stimulas (PAS) technique can demonstrate the presence of sinoatrial entrance block (SAEB), both its prevalence and its relationship to antegrade SA conduction are unknown. Using PAS, we determined the incidence of SAEB in 59 patients with known or suspected dysrrhythmias or conduction defects to be 6.8%. Using catheter recorded sinus node electrograms (SNE), we then directly measured sinoatrial conduction time (SACT) in three patients with SAEB. Antegrade SACT was normal in two and prolonged in one. Only the latter had sinus node dysfunction recognized by ECG and/or conventional sinus node testing. We conclude that SAEB occurs infrequently, may occur when antegrade SACT is normal, is probably analogous to behavior at the AV node, and should not be used as an indicator of sick sinus syndrome. PMID:7315700

Reiffel, J A; Gang, E; Livelli, F; Gliklich, J; Bigger, J T

1981-12-01

288

Real-time holographic analysis of the modal and dynamic characteristics of an advanced graphite-epoxy missile flight control structure  

NASA Astrophysics Data System (ADS)

Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under stress. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. Real-time dynamic testing of the model behavior of aerodynamic control structures for advanced missiles systems has always required advanced instrumentation for data collection in either actual flight test or wind-tunnel simulations. Advanced optical holographic techniques are alternate methods which define actual behavioral data on the ground in a noninvasive hardware-in-the-loop environment. These methods offer significant insight in both the development and subsequent operational test and modeling of advanced composite control structures and their integration with total vehicle system dynamics. Structures and materials can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural models. Holographic Interferometry has offered a powerful tool to aid in the primary engineering and development of advanced graphite-epoxy fiber composite structures which are finding increased use in advanced aerodynamic platforms. Smart weapon and missile control structure applications must consider environments where extremes in vibration and mechanical stresses can affect both operation and structural stability. These are ideal requisites for analysis using advanced holographic methods in the initial design and subsequent test of such advanced components. Holographic techniques are non-destructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometries. Deriving such information without having to resort to in-flight data collection methods can be crucial to the determination of mechanical configurations and designs, as well as critical operational parameters.

Fein, Howard

1997-07-01

289

Characteristics of climate and environmental signals with the various time scales from past 720,000 years in Dome Fuji ice core, Antarctica  

NASA Astrophysics Data System (ADS)

Two deep ice cores (DF1: 2503m and DF2: 3035m) at Dome Fuji, Antarctica have the in-depth information of global environmental change from present to the past 720,000 years. We made the data set of major ion concentration, dust concentration and stable isotope ratio which were analyzed 10cm sample every 50cm from 2400m to 3035m using the DF2 core. The age of this depth was covered from 300,000 to 720,000 years before. Using the DF1 core, major chemical species were carried out using 7-10cm ice samples cut out of the 50 cm-long spaced from 0.5 to 2.5m. All data was averaged by every 5 m or every 1,000 years. The indexes of climate and environment are the following elements; MSA-, Cl-, NO3-, SO42-, H+ (calculated from pH), Na+, NH4+, K+, Mg2+, Ca2+, ss-Na+, nss-Cl-, nss-SO42-, nss-K+, nss-Mg2+, nss-Ca2+, dD, d18O, d-excess, dust, pH and electrical conductivity. There is a feature in correlation respectively by the climatic stage. dD or d18O which becomes the index of the temperature and the environmental elements (for example, Na+ and Mg2+) indicate the strong negative correlation, but its degree is different depending on the climatic stages. Deep ice core records are compared with initial conditions (precipitation and surface snow). Time scales of our studies are daily, yearly, millennial-scales and glacial-interglacial cycle. We show the difference of the chemistry of surface snow by the difference of the snow type in the same area.

Motoyama, Hideaki; Fuji ice core project members, Dome

2013-04-01

290

Characteristic Curves.  

ERIC Educational Resources Information Center

|Describes an experiment designed to help students gain a better understanding of the characteristics of various electronic components by incorporating a dual-trace oscilloscope in the X-Y mode in addition to direct observations of phase shifts of various signals into a laboratory exercise. (ZWH)|

Walkiewicz, Thomas A.; Kirk, James R.

1994-01-01

291

Dryline Characteristics  

NSDL National Science Digital Library

A 'dryline' is a characteristic boundary, seen in the U.S. Southern plains, between dry air moving up from the Mexican Plateau and moist air from the Gulf of Mexico. In this activity, students will learn how to recognize a dryline by viewing animations of several atmospheric variables (air temperature, dew point, solar radiation, and wind). They will examine each animation for patterns and changes, and answer questions about what they see. Links to the animations and to viewing software are provided.

292

Decay time characteristics of La2O2S:Eu and La2O2S:Tb for use within an optical sensor for human skin temperature measurement  

SciTech Connect

We focus on the development of a remote temperature sensing technology, i.e., an optical laser-based sensor, using thermographic phosphors for medical applications, particularly within an electromagnetically hostile magnetic resonance imaging (MRI) environment. A MRI scanner uses a strong magnetic field and radio waves to generate images of the inside of the body. The quality of the image improves with increasing magnetic resonance; however, the drawback of applying a greater magnetic strength is the inducement of heat into the body tissue. Therefore, monitoring the patient's temperature inside MRI is vital, but until now, a practical solution for temperature measurement did not exist. We show europium doped lanthanum oxysulphide (La2O2S:Eu) and terbium doped lanthanum oxysulphide (La2O2S:Tb) are both temperature sensitive to a low temperature range of 10-50 deg. C when under ultraviolet (UV) excitation. The emission spectra and decay time characteristics of these phosphors were demonstrated. The results indicate that La2O2S:Eu has a quenching rate of 13.7 m deg. C{sup -1} and 4 m deg. C{sup -1} at 512 nm and 538 nm, respectively. In addition, La2O2S:Tb has a lower quenching rate of 4.19 m deg. C{sup -1} at 548 nm due to its faster decay time.

Yap, Sook Voon; Ranson, Robert M.; Cranton, Wayne M.; Koutsogeorgis, Demosthenes

2008-09-20

293

Effect of betatizing time on the grain growth and transformation characteristics in rapid-solidified Cu-12.7Al-3.9Ni based SMA ribbons with different solidification structures  

NASA Astrophysics Data System (ADS)

The effect of betatizing time on the microstructure, grain growth rate and transformation characteristics of Cu-AI-Ni based shape memory alloy was investigated in rapid-solidified ribbons with equiaxed, columnar and fibrous structures. The initial grain sizes of the as-spun ribbons were 6, 2.5 and 0.5 ?m in the order of wheel speed of 10, 35 and 50 m/sec. However, the grain size after betatizing at 973 K for 10^4 sec was almost same value at approximately 10 ?m in all ribbons due to the rapid grain growth rate of columnar and fibrous structures. Comparing the peaks with betatizing time at each wheel speed, the sharp peaks of the ribbons with wheel speeds of 10 and 35 m/sec became broader due to a decrease in the grain boundary area acting as a nucleation site. However, the broad peak of the ribbon with the wheel speed of 50 m/sec became normal by betatizing for 10^2 sec because of the disappearance of the parent phase retained in the as-spun state. The higher wheel speed was, the more the dM3/dt was increasing due to the rapid grain growth of columnar and fibrous structures by betatizing. The M5 temperatures of all the melt-spun ribbons after betatizing for 10^4 sec were around 420 K, which came close to that of the mother alloy because of the high surface area/volume ratio of the melt-spun ribbon.

Jang, W. Y.; Jeep, K. K.; Lee, Y. S.

2003-10-01

294

Time After Time  

NSDL National Science Digital Library

Students use a variety of strategies and techniques to develop an understanding of telling time. They use estimation to tell time, using seconds, hours, and minutes in order to choose reasonable time estimates for given activities. Students use pictures, words, and symbols in order to read, write, and represent time to the nearest minute. Students determine elapsed time when given a start time, counting up using minutes and hours.

Service, National S.

2009-04-22

295

Timely Time Estimates  

Microsoft Academic Search

\\u000a Estimations of execution time are essential for design and development of safety critical embedded real-time systems, such\\u000a as avionics, automotive and aerospace systems. In such systems, execution time is part of the functional specification, hence\\u000a correct behaviour requires sufficiently powerful target hardware to meet deadlines or achieve required polling rates, etc.\\u000a Yet, grossly overestimated resource usage results in excessive cost

Andreas Holzer; Visar Januzaj; Stefan Kugele; Michael Tautschnig

2010-01-01

296

Estimation of illumination characteristics.  

PubMed

The description of the relation between the one-parameter subgroups of a group and the differential operators in the Lie-algebra of the group is one of the major topics in Lie-theory. We use this framework to derive a partial differential equation which describes the relation between the time-change of the spectral characteristics of the illumination source and the change of the color pixels in an image. We introduce and justify the usage of conical coordinate systems in color space. We also derive the differential equation describing the illumination change and illustrate the algorithm with some simulation examples. PMID:18249676

Lenz, R

2001-01-01

297

Hydrological connectivity of hillslopes and streams: characteristic ...  

Treesearch

Title: Hydrological connectivity of hillslopes and streams: characteristic time scales ... and computed transit times for multiple runoff components for a series of storms ... quick flow ratio of 0.58 when antecedent rainfall was greater than 20 mm.

298

Switching Characteristics of Ferroelectric Transistor Inverters  

Microsoft Academic Search

This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, ?phl and ?plh are presented along with the output voltage rise and fall times, ?rise and ?fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times

Crystal Laws; Cody Mitchell; Todd C. MacLeod; Fat D. Ho

2011-01-01

299

Wavelet analysis of paleomagnetic data: 1. Characteristic average times (5–10 kyr) of variations in the geomagnetic field during and immediately before and after the Early Jaramillo reversal (Western Turkmenistan)  

Microsoft Academic Search

Joint wavelet analysis of complete and downsampled series of paleomagnetic and petromagnetic characteristics of rocks in the\\u000a Matuyama-Jaramillo transitional zone in the Adzhidere section is used to extract paleomagnetic data whose variations are associated\\u000a with the geomagnetic field alone and data correlating with variations in petromagnetic parameters. It supposed that this correlation\\u000a can be caused by an external factor affecting

G. Z. Gurarii; M. V. Aleksyutin; N. Ataev

2007-01-01

300

Adjoint operator approach in marginal separation theory  

NASA Astrophysics Data System (ADS)

Thin airfoils are prone to localized flow separation at their leading edge if subjected to moderate angles of attack ?. Although 'laminar separation bubbles' at first do not significantly alter the airfoil performance, they tend to 'burst' if a is increased further or perturbations acting upon the flow reach a certain intensity. This then leads either to global flow separation (stall) or triggers the laminar-turbulent transition process within the boundary layer flow. The present paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number Re --> ?, commonly referred to as marginal separation theory (MST). A new approach based on the adjoint operator method is presented to derive the fundamental similarity laws of MST and to extend the analysis to higher order. Special emphasis is placed on the breakdown of the flow description, i.e. the formation of finite time singularities (a manifestation of the bursting process), and its resolution based on asymptotic reasoning. The computation of the spatio-temporal evolution of the flow in the subsequent triple deck stage is performed by means of a Chebyshev spectral method. The associated numerical treatment of fractional integrals characteristic of MST is based on barycentric Lagrange interpolation, which is described in detail.

Braun, Stefan; Scheichl, Stefan; Kluwick, Alfred

2013-10-01

301

Generic adversary characteristics: summary report  

Microsoft Academic Search

The adversaries studied were found to be complex, often unpredictable, and dynamic. The adversary typically goes through a complex decision-making process between the time a potential target is identified and the moment the decision to act is made. This study analyzes the adversary characteristics, and the following conclusions are made: one of the least likely methods of attack is an

J. B. Jr. Stewart; J. J. Davidson; H. B. Jones; C. H. Fulwiler; S. A. Mullen

1978-01-01

302

How Reaction Time, Update Time, and Adaptation Time Influence the Stability of Traffic Flow  

Microsoft Academic Search

When modeling the acceleration and decel- eration of drivers, there are three characteristic time con- stants that influence the dynamics and stability of traffic flow: The reaction time of the drivers, the velocity adap- tation time needed to accelerate to a new desired velocity, and the numerical update time. By means of numerical simulations with a time-continuous car-following model, we

Arne Kesting; Martin Treiber

2008-01-01

303

Channel Holding Time in Wireless Cellular Communications with General Distributed Session Time and Dwell Time  

Microsoft Academic Search

Channel holding time is fundamental to teletraffic analysis of wireless cellular networks. This quantity depends on user's mobility which can be characterized by the dwell time, and the traffic model which is associated with the unencumbered session time. In this paper, under a general assumption on the distributions of unencumbered session time and dwell time, the characteristics of new call

Xian Wang; Pingzhi Fan

2007-01-01

304

The Use of a priori Information in ICA-Based Techniques for Real-Time fMRI: An Evaluation of Static/Dynamic and Spatial/Temporal Characteristics  

PubMed Central

Real-time brain functional MRI (rt-fMRI) allows in vivo non-invasive monitoring of neural networks. The use of multivariate data-driven analysis methods such as independent component analysis (ICA) offers an attractive trade-off between data interpretability and information extraction, and can be used during both task-based and rest experiments. The purpose of this study was to assess the effectiveness of different ICA-based procedures to monitor in real-time a target IC defined from a functional localizer which also used ICA. Four novel methods were implemented to monitor ongoing brain activity in a sliding window approach. The methods differed in the ways in which a priori information, derived from ICA algorithms, was used to monitor a target independent component (IC). We implemented four different algorithms, all based on ICA. One Back-projection method used ICA to derive static spatial information from the functional localizer, off-line, which was then back-projected dynamically during the real-time acquisition. The other three methods used real-time ICA algorithms that dynamically exploited temporal, spatial, or spatial-temporal priors during the real-time acquisition. The methods were evaluated by simulating a rt-fMRI experiment that used real fMRI data. The performance of each method was characterized by the spatial and/or temporal correlation with the target IC component monitored, computation time, and intrinsic stochastic variability of the algorithms. In this study the Back-projection method, which could monitor more than one IC of interest, outperformed the other methods. These results are consistent with a functional task that gives stable target ICs over time. The dynamic adaptation possibilities offered by the other ICA methods proposed may offer better performance than the Back-projection in conditions where the functional activation shows higher spatial and/or temporal variability.

Soldati, Nicola; Calhoun, Vince D.; Bruzzone, Lorenzo; Jovicich, Jorge

2013-01-01

305

A proposal of the diagnosis-dynamic characteristic (DDC) model describing the relation between search time and confidence levels for a dichotomous judgment, and its application to ROC curve generation  

NASA Astrophysics Data System (ADS)

When physicians inspect an image, they make up a certain degree of confidence that the image are abnormal; p(t), or normal; n(t)[n(t)=1-p(t)]. After infinite time of the inspection, they reach the equilibrium levels of the confidence of p*=p(?) and n*=n(?). There are psychological conflicts between the decisions of normal and abnormal. We assume that the decision of "normal" is distracted by the decision of "abnormal" by a factor of k(1 + ap), and in an inverse direction by a factor of k(1 + bn), where k ( > 0) is a parameter that relates with image quality and skill of the physicians, and a and b are unknown constants. After the infinite time of inspection, the conflict reaches the equilibrium, which satisfies the equation, k(1 + ap*)n* = k(1 + bn*)p*. Here we define a parameter C, which is 2p*/[p*(1 - p*)]. After the infinite time of inspection, the conflict reaches the equilibrium, which satisfies t that changes in the confidence level with the time (dp/dt) is proportional to [k(1+ap)n - k(1+bn)p], i.e. k[-cp2 + (c - 2)p + 1]. Solving the differential equation, we derived the equation; t(p) and p(t) depending with the parameters; k, c, S. S (0-1) is the value arbitrary selected and related with probability of "abnormal" before the image inspection (S = p(0)). Image reading studies were executed for CT images. ROC curves were generated both by the traditional 4-step score-based method and by the confidence level; p estimated from the equation t(p) of the DDC model using observed judgment time. It was concluded that ROC curves could be generated by measuring time for dichotomous judgment without the subjective scores of diagnostic confidence and applying the DDC model.

Matsumoto, Toru; Fukuda, Nobuo; Furukawa, Akira; Suwa, Koji; Wada, Shinichi; Matsumoto, Mitsuomi; Sone, Shusuke

2006-03-01

306

An Assessment of Wind Turbine Characteristics and Wind Energy Characteristics for Electricity Production  

Microsoft Academic Search

This work is an analysis of wind turbine characteristics and wind energy characteristics of four regions around Elazig, Turkey, namely Maden, Agin Elazig and Keban. Wind speed data and wind direction in measured hourly time-series format is statistically analyzed based on 6 years between 1998 and 2003. The probability density distributions are derived from time-series data and distributional parameters are

E. Kavak Akpinar; S. Akpinar

2006-01-01

307

Thermistor Characteristics and Stability.  

ERIC Educational Resources Information Center

|Discusses the uses of thermistors in teaching electronics and semiconductors. Describes how to experimentally measure and graph the characteristics of a thermistor. Suggests one possible approach to understand the shapes of the characteristics. (CW)|

Fricker, H. S.

1987-01-01

308

A real-time semi-quantitative RT-PCR assay demonstrates that the pilE sequence dictates the frequency and characteristics of pilin antigenic variation in Neisseria gonorrhoeae  

Microsoft Academic Search

A semi-quantitative real-time RT-PCR assay was designed to measure gonococcal pilin antigenic- variation (SQ-PCR Av assay). This assay employs 17 hybridization probe sets that quantitate sub- populations of pilin transcripts carrying different silent pilin copy sequences and one set that detects total pilE transcript levels. Mixtures of a DNA stan- dard carrying the silent copy being detected and a clone

Melissa S. Rohrer; Matthew P. Lazio; H. Steven Seifert

2005-01-01

309

A two-stage fixed-bed reactor for direct hydrotreatment of volatiles from the hydropyrolysis of biomass: effect of catalyst temperature, pressure and catalyst ageing time on product characteristics  

Microsoft Academic Search

This investigation involved the hydropyrolysis of biomass (eucalyptus globulus) and the immediate catalytic hydrocracking of pyrolytic oils in the second stage of the reactor. The effects of temperature, pressure and the catalyst ageing time on the final product tar have been studied using the catalyst Zeolite H-ZSM5. The catalytically hydrocracked tar\\/oil products were characterised and compared with the hydropyrolysis product

R. V Pindoria; A Megaritis; A. A Herod; R Kandiyoti

1998-01-01

310

Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts-11-strain M. gallisepticum vaccination on digestive and reproductive organ characteristics of commercial egg-laying hens.  

PubMed

Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in conjunction with F-strain M. gallisepticum (FMG) inoculation overlays at 2 different age periods during lay on the digestive and reproductive organ characteristics of commercial egg-laying hens. In each trial, the following 4 treatments were utilized: sham vaccination at 10 wk of age, ts-11MG vaccination at 10 wk of age, ts-11MG at 10 wk of age overlaid by FMG inoculation at 22 wk of age, and ts-11MG at 10 wk of age overlaid by FMG at 45 wk of age. Necropsies were performed at the end of both trials (58 wk of age), using 2 birds from each of 4 replicate units per treatment, to observe treatment effects on the following parameters: liver weight, liver lipid and moisture concentrations, incidence of fatty liver hemorrhagic syndrome, ovary weight, number of mature ovarian follicles, and the total and segmental weights, lengths, and histologies of the oviduct and small intestine. Treatments affected only vaginal length as a percentage of total oviduct length. Vaginas were relatively longer in hens that had only been vaccinated with ts-11MG at 10 wk in comparison to all the other treatment groups, including controls. Except for relative vaginal length, the digestive and reproductive organs of layers were not influenced by the ts-11MG and FMG treatment regimens imposed in this study. These results confirm that when coupled with FMG inoculations during lay, prelay ts-11MG vaccinations may be a practical substitute for prelay FMG inoculations for providing continual protection against field-strain M. gallisepticum infections in layers. PMID:19359686

Vance, A M; Branton, S L; Collier, S D; Gerard, P D; Peebles, E D

2009-05-01

311

Characteristics and Capabilities of Walsh Functions.  

National Technical Information Service (NTIS)

This is a final scientific report on the characteristics and capabilities of Walsh functions. Research achievements in the areas of (a) Walsh transform of sampled time functions and sampling principle, (b) Walsh-function analysis of discrete dyadic-invari...

D. K. Cheng

1974-01-01

312

Determine Binding Characteristic of Experimental Ioplex Membranes.  

National Technical Information Service (NTIS)

The purpose of the study was to determine the metal binding characteristics of the Amicon ioplex membranes. Three experimental membranes, neutral, anionic, and cationic ioplex membranes were evaluated to determine the effect of exposure time on the uptake...

1967-01-01

313

Physical Characteristics of Spent LMFBR Fuel.  

National Technical Information Service (NTIS)

The present paper describes physical characteristics of fast breeder reactor fuels and analyses calculated isotope composition of spent fuel and dependance of fission product activity on cooling time. Requirements for a decontamination factor from fission...

O. D. Bakumenko E. M. Ikhlov M. Y. Kulakovskij M. F. Troyanov A. G. Tsikunov

1976-01-01

314

Hunter-fisherman characteristics: factors in wildlife management and ...  

Treesearch

Description: Research on the characteristics and motivations of hunters and fishermen is examined for factors ... Characteristics related to the learning experience, time for participation, utilization and accessibility of the ... Language: English.

315

The First Time  

ERIC Educational Resources Information Center

|In this article, the author narrates her experience of meeting a Montessori kid for the first time and shares the characteristics she observed in Montessori students. The author was working as director of academic resources in university housing at the University of Wisconsin-Madison and met Jason, a pre-med sophomore who was the resident…

Black, Beth

2011-01-01

316

Time Dependent Fluids  

ERIC Educational Resources Information Center

|Discusses the flow characteristics of thixotropic and negative thixotropic fluids; various theories underlying the thixotropic behavior; and thixotropic phenomena exhibited in drilling muds, commercial paints, pastes, and greases. Inconsistencies in the terminology used to label time dependent effects are revealed. (CC)|

Collyer, A. A.

1974-01-01

317

Timing subsystem development  

Microsoft Academic Search

In the predominately digital DCS, a requirement exists to coordinate clocks at geographically distinct nodes to handle switched digital traffic and provide a general system timing capability. Aside from the characteristics of the clocks, medium, and link equipment, the synchronization technique itself is an important aspect in considering overall network performance. This document presents the findings of a program in

K. R. Backe

1982-01-01

318

High resolution 3-D imaging for characteristics of (111)-oriented Pb(Zr0.35Ti0.65)O3 thin film by using time-of-flight secondary ion mass spectrometry and piezoresponse force microscopy  

NASA Astrophysics Data System (ADS)

The properties of Pb(Zr0.35Ti0.65)O3 (PZT) thin films, ˜150-nm thick, deposited on an electrode Pt (111)/Ti layer and an SiO2/Si (100) substrate using a chemical sol-gel solution deposition method were investigated by using the high resolution X-ray diffraction (HR-XRD), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and piezoresponse force microscopy (PFM) systems. The in-plane orientations of crystal phase for the PZT film were confirmed with a 3-D pole-figure measurement method. The degree of the c-axis orientation was also measured by 2 ?-w scans and a scan (rocking-curve) measurement. Through 2D and 3D images by TOF-SIMS, we could confirm visually the concentration distribution for the surface and diffusion status to depth direction. Through atomic force microscopy (AFM) techniques, the grain profiles in the local area were characterized in detail. The 3-D images of the phase and magnitude for the polarization behavior along the applying electric field were displayed by using PFM techniques.

Shin, Hyun-Chang; Song, Joon-Tae

2011-09-01

319

Universal Time  

NSDL National Science Digital Library

This article explains the concept of 'Universal Time' (UT), sometimes referred to as 'Coordinated Universal Time' (UTC). Topics include how UTC is measured, who uses it, and a brief discussion of the historical context of this time standard.

320

TRAFFIC CHARACTERISTICS OF INDIA  

Microsoft Academic Search

The revolution in the automobile industry and liberalised economy has led to tremendous increase in the vehicle ownership levels. This has resulted in changing traffic characteristics on road network. In this paper an attempt has been made to analyse the changing traffic composition trends, speed characteristics and travel patterns by taking few case studies. Further, the impact of changing traffic

Santosh A. JALIHAL; T. S. Reddy

321

GNSS Signals Characteristics  

Microsoft Academic Search

The paper deals with second order signals characteristics for satellite navigation systems. The main goal of the paper is to simplify and clarify signals analysis task by introducing a system of signals characteristics and their mutual relations. The conception of the system is based on the fact that the structure of navigation signals is partially given since the signals should

P. Kacmarik; P. Kovar

2007-01-01

322

VARIABLE TIME DELAY MEANS  

DOEpatents

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

Clemensen, R.E.

1959-11-01

323

CEO characteristics, organizational characteristics and information technology adoption in small businesses  

Microsoft Academic Search

The importance of information technology (IT) to businesses is widely acknowledged. Yet, while large businesses have been using computers for some time, small businesses have been slow in adopting IT. The literature on technological innovation suggests that there are two main classes of variables that are important in determining adoption of an innovation: individual characteristics and organizational characteristics. As IT

J. Y. L. Thong; Chee-Sing Yap

1995-01-01

324

Congruence of Real and Ideal Job Characteristics: A Focus on Sex, Parenthood Status, and Extrinsic Characteristics.  

ERIC Educational Resources Information Center

Intrinsic and extrinsic job characteristics were studied in relation to perceived real-ideal job characteristic congruence for a sample of male and female full-time lawyers (N=60). Results indicated that sex differences exist in perceived real-ideal congruence even when variables known to covary with sex in the work setting are controlled.…

Weinberg, Sharon L.; Tittle, Carol Kehr

1987-01-01

325

Reconstruction of time-delayed feedback systems from time series  

Microsoft Academic Search

For various classes of time-delay systems we propose the methods of their model delay-differential equation reconstruction from time series. The methods are based on the characteristic location of extrema in the time series of time-delay systems and the projection of infinite-dimensional phase space of these systems to suitably chosen low-dimensional subspaces. We verify our methods by using them for the

M. D. Prokhorov; V. I. Ponomarenko; A. S. Karavaev; B. P. Bezruchko

2005-01-01

326

Time-Response Characteristics of an Aluminum-Oxide Sensor.  

National Technical Information Service (NTIS)

A laboratory study of aluminum-oxide water-vapor sensors has been made to determine whether this type of sensor is suitable for measuring the concentration of water vapor in the stratosphere aboard a balloon-borne probe. The stationary afterglow facility ...

J. A. Vanderhoff

1973-01-01

327

Time Structure Of Cardiovascular Characteristics In Clinically Healthy Human Pregnancy  

Microsoft Academic Search

Blood pressure (BP) and heart rate (HR) were automatically monitored with a fully ambulatory noninvasive device at -1-hour intervals and for a total of 76 days in each of two consecutive pregnancies in a 31-year-old clinically healthy woman. Regression analysis of circadian parameters obtained by least-squares rthythmometry reveals patterns of variation of rhythm-adjusted means (M) and amplitudes (A) with gestational

R. C. Hermida; Diana E. Ayala; Franz Halberg

1991-01-01

328

AEROSOL CHARACTERISTICS AND VISIBILITY  

EPA Science Inventory

This report summarizes progress in measuring the optical properties of aerosols and in relating aerosol characteristics to visibility reduction made in the author's laboratory during the period 1965-1971. An instrument, the integrating nephelometer, which measures the scattering ...

329

Characteristics of Scientific Databases.  

National Technical Information Service (NTIS)

The purpose of this paper is to examine the kinds of data and usage of scientific databases and to identify common characteristics among the different disciplines. Most scientific databases do not use general purpose database management systems (DBMSs). T...

A. Shoshani F. Olken H. K. T. Wong

1984-01-01

330

Sequencing Time  

NSDL National Science Digital Library

In this activity, students gain an understanding of relative and numerical time by placing events in sequence and assigning relative times to the events. This will familarize them with the methods used by scientists to develop the geologic time scale. This activity contains objectives, materials, procedure, and extensions.

2007-12-12

331

Housing characteristics 1993  

SciTech Connect

This report, Housing Characteristics 1993, presents statistics about the energy-related characteristics of US households. These data were collected in the 1993 Residential Energy Consumption Survey (RECS) -- the ninth in a series of nationwide energy consumption surveys conducted since 1978 by the Energy Information Administration of the US Department of Energy. Over 7 thousand households were surveyed, representing 97 million households nationwide. A second report, to be released in late 1995, will present statistics on residential energy consumption and expenditures.

NONE

1995-06-01

332

Toxicity characteristic final rule  

SciTech Connect

Under the Resource Conservation and Recovery Act Section 3001, EPA is charged with identifying characteristics of hazardous waste. Hazardous waste characteristics are mechanisms for identifying wastes as hazardous, and thus subject to regulation. The Extraction Procedure Toxicity Characteristic (EPTC) is one of four existing characteristics of hazardous waste, along with ignitability, corrosivity, and reactivity. The EPTC relates directly to the toxicity of a waste and its mobility and is intended to determine the potential for ground-water contamination through leaching of constituents from land disposed wastes. The existing EPTC identifies wastes as hazardous based on regulatory levels applied to concentrations in waste leachate extracted during the EP Toxicity Test. Eight metals and six organic compounds currently are regulated under the EPTC. The Hazardous and Solid Waste Amendments of 1984 direct EPA to improve the EP and to identify additional hazardous waste characteristics, including measures of toxicity. The Toxicity Characteristic final rule will address these mandates by development of a new leaching procedure and by adding additional constituents.

Goodrich-Mahoney, J.W. (Environmental Protection Agency, Washington, DC (USA))

1989-01-01

333

Hydrodynamic characteristics of UASB bioreactors.  

PubMed

The hydrodynamic characteristics of UASB bioreactors operated under different organic loading and hydraulic loading rates were studied, using three laboratory scale models treating concocted sucrose wastewater. Residence time distribution (RTD) analysis using dispersion model and tanks-in-series model was directed towards the characterization of the fluid flow pattern in the reactors and correlation of the hydraulic regime with the biomass content and biogas production. Empty bed reactors followed a plug flow pattern and the flow pattern changed to a large dispersion mixing with biomass and gas production. Effect of increase in gas production on the overall hydraulics was insignificant. PMID:23505813

John, Siby; Tare, Vinod

2011-10-01

334

Takeoff characteristics of turbofan engines  

SciTech Connect

The present derivation of reliable formulas for the takeoff characteristics of turbofan-powered aircraft, encompassing ground-roll distance and time, fuel consumption, etc, incorporates ground effect-induced drag reduction. This drag reduction factor is varied according to type of aircraft; the turbofans in question may be of high-bypass transport-aircraft type or of low bypass and afterburner-employing configuration, as is typically the case in military aircraft. It is shown that bypass ratio variations have little influence on takeoff ground-rolling distance.

Suh, Y.B. (Texas A M Univ., College Station (USA))

1990-05-01

335

Channel holding time in mobile cellular networks with heavy-tailed distributed cell dwell time  

Microsoft Academic Search

Channel holding time is fundamental for the performance analysis\\/evaluation of mobile cellular networks. Channel holding time depends on both call holding time and cell dwell time. In the literature, many assumptions on cell dwell time distribution have been done and different channel holding time characteristics have been obtained. However, to our knowledge, channel holding time statistics has not been obtained

Anum L. Enlil Corral-Ruiz; Felipe A. Cruz-Perez; Genaro Hernandez-Valdez

2011-01-01

336

Velocity fluctuation enhancement in the transition to turbulence in a pipe  

NASA Astrophysics Data System (ADS)

A laser-Doppler velocimetry study of the features of a duct flow around the laminar-turbulent transition under the influence of a finite perturbation is reported. Through the spectral analysis of the light scattered by particles crossing interference fringes, the time-average velocity and the velocity fluctuation profiles are studied. It is shown that the ratio between the magnitude of the velocity fluctuations and the axial time-average velocity exhibits a sharp peak in the transition region. It is pointed out how that feature is independent of the discontinuities inducing the perturbation at the entrance as well as of the position downstream.

Banfi, G. P.; de Micheli, R.; Henin, A.

1981-04-01

337

Three-dimensional modeling of diesel engine intake flow, combustion and emissions  

SciTech Connect

A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/well interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation and the intake flow process. Improved and/or new submodels which have been completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo`vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and, finally the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To data, comparisons have been made with measured engine cylinder pressure and heat flux data for homogeneous charge, spark-ignited and compression-ignited engines, and also limited comparisons for diesel engines. The model results are in good agreement with the experiments.

Reitz, R.D.; Rutland, C.J. [Wisconsin Univ., Madison, WI (United States). Engine Research Center

1992-03-01

338

Three-dimensional modeling of diesel engine intake flow, combustion and emissions  

SciTech Connect

A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/well interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation and the intake flow process. Improved and/or new submodels which have been completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo'vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and, finally the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To data, comparisons have been made with measured engine cylinder pressure and heat flux data for homogeneous charge, spark-ignited and compression-ignited engines, and also limited comparisons for diesel engines. The model results are in good agreement with the experiments.

Reitz, R.D.; Rutland, C.J. (Wisconsin Univ., Madison, WI (United States). Engine Research Center)

1992-03-01

339

Time interpolator  

NASA Astrophysics Data System (ADS)

A time interpolator for the measurement of time difference using digital and analog techniques is described. Emitter Coupled Logic (ECL) and high frequency techniques were used. The difficulty with ECL is to keep the connections as short as possible and to properly terminate the output to avoid reflections. The digital part of the interpolator consists of a continuous clock and logic which converts the input signal into a start and stop signal. The analog part consists of a time to amplitude converter and an analog to digital convertor. The maximum measuring time is 6.4 microns with a 100 ps resolution.

Deblok, M.

1990-06-01

340

Geologic Time  

NSDL National Science Digital Library

The Earth is very old -- 4.5 billion years or more -- according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Newman, William L.

1997-01-01

341

Clock Time  

NSDL National Science Digital Library

You will have practice reading the time on a clock and pairing it up with its digital or written text match. Complete this as quickly as you can in order to beat the clock! Stop the Clock 1 Stop the Clock 2 Stop the Clock 6 Each of these links varies in degree of difficulty. They progressively go up in difficulty in the time you are telling. The first starts out telling time in half hour intervals. The following activity progress to fifteen minutes. The final activity is matching up the time on the clock to ...

Greene, Miss

2010-04-26

342

Geologic time  

USGS Publications Warehouse

The Earth is very old 4 1/2 billion years or more according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Newman, William L.

2000-01-01

343

Time Utilities  

NASA Astrophysics Data System (ADS)

Time Utilities are software tools that, in principal, allow one to calculate BJD to a precision of 1 ?s for any target from anywhere on Earth or from any spacecraft. As the quality and quantity of astrophysical data continue to improve, the precision with which certain astrophysical events can be timed becomes limited not by the data themselves, but by the manner, standard, and uniformity with which time itself is referenced. While some areas of astronomy (most notably pulsar studies) have required absolute time stamps with precisions of considerably better than 1 minute for many decades, recently new areas have crossed into this regime. In particular, in the exoplanet community, we have found that the (typically unspecified) time standards adopted by various groups can differ by as much as a minute. Left uncorrected, this ambiguity may be mistaken for transit timing variations and bias eccentricity measurements. We recommend using BJD_TDB, the Barycentric Julian Date in the Barycentric Dynamical Time standard for any astrophysical event. The BJD_TDB is the most practical absolute time stamp for extraterrestrial phenomena, and is ultimately limited by the properties of the target system. We compile a general summary of factors that must be considered in order to achieve timing precisions ranging from 15 minutes to 1 ?s, and provide software for download and online webapps for use.

Eastman, Jason

2012-06-01

344

Time response of plastic scintillators  

Microsoft Academic Search

Time-response characteristics of eight commercial plastic scintillators ; have been studied. Samples were excited by 50 ps electron or bremsstrahlung ; pulses. Sampling techniques were used to record the signal from a fast vacuum ; photodiode. Effects of surface preparation on time response were studied. The ; observed fwhm (in ns) for the three fastest plastics was 1.5, 2.0, and

P. B. Lyons; J. Stevens

1974-01-01

345

Phenomenal characteristics of cryptomnesia.  

PubMed

Qualitative characteristics of cryptomnesia, or unintentional plagiarism were investigated. In Experiment 1 we compared accurate and inaccurate source attributions in terms of their level of confidence using instructions that did not require a fixed number of responses. Confidence was lower for plagiarised responses than for correct responses. Nevertheless, participants provided high ratings of certainty for a large proportion of their plagiarised responses. In Experiment 2 the phenomenological differences between plagiarised recall and veridical recall were compared by using an adaptation of the memory characteristics questionnaire (Johnson, Foley, Suengas, & Raye, 1988). Correct responses were associated with more experiential detail than plagiarised responses. However, a considerable number of plagiarised responses were accompanied by a confident memory of at least one qualitative characteristic. Results are discussed in terms of the source monitoring framework developed by Johnson, Hashtroudi, and Lindsay (1993). PMID:12653485

Brédart, Serge; Lampinen, James M; Defeldre, Anne-Catherine

2003-01-01

346

Characteristics of intuitive nurses.  

PubMed

A description is provided of the process used to verify characteristics of intuitive nurses that had been reported in the literature. These characteristics supplied the framework for construction of the Miller Intuitiveness Instrument (MII) reported earlier (Miller, 1993). Evidence for validity of the MII was provided in the Miller (1993) study by examining factor analyses and correlations with the intuitive component of the Myers-Briggs Type Indicator (MBTI). The following characteristics were subsequently verified: Intuitive nurses are willing to act on their intuitions, are skilled clinicians, and incorporate a spiritual component in their practices. In addition, intuitive nurses express an interest in the abstract nature of things and are risk takers. Intuitive nurses prefer intuition to sensing (as reflected by the MBTI) as a way to take in information. They are extroverted and express confidence in their intuitions. Likewise, nurses who delay making decisions until all the information is in are more intuitive than those who make decisions abruptly. PMID:7778312

Miller, V G

1995-06-01

347

Commercial Buildings Characteristics, 1992  

SciTech Connect

Commercial Buildings Characteristics 1992 presents statistics about the number, type, and size of commercial buildings in the United States as well as their energy-related characteristics. These data are collected in the Commercial Buildings Energy Consumption Survey (CBECS), a national survey of buildings in the commercial sector. The 1992 CBECS is the fifth in a series conducted since 1979 by the Energy Information Administration. Approximately 6,600 commercial buildings were surveyed, representing the characteristics and energy consumption of 4.8 million commercial buildings and 67.9 billion square feet of commercial floorspace nationwide. Overall, the amount of commercial floorspace in the United States increased an average of 2.4 percent annually between 1989 and 1992, while the number of commercial buildings increased an average of 2.0 percent annually.

Not Available

1994-04-29

348

Timing Nutriceuticals?  

PubMed Central

Evidence on time-dependent effects of drugs and nutrition is succinctly reviewed in order to illustrate and advocate investigations of the timing of nutriceuticals. Emphasis is placed on the merits of coordinated, individually, inferentially, statistically examined sets of N-of-1 studies.

Halberg, Franz; Cornelissen, Germaine; Singh, R.B.

2011-01-01

349

Time Management  

ERIC Educational Resources Information Center

|The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as…

Stoilov, Todor, Ed.

2012-01-01

350

Characterizing Bus Transit Passenger Wait Times.  

National Technical Information Service (NTIS)

Mathematical models are developed to predict bus passenger waiting time components. A statistically significant quantity of waiting time data, including related passenger attributes, transits system characteristics and bus frequency, were collected by dir...

M. D. Salek R. B. Machemehl

1999-01-01

351

Work Schedules, Job Characteristics, Parenting Practices and Children's Outcomes  

Microsoft Academic Search

The goal of this research was to find evidence for serious negative effects of employment conditions on different measures of child outcomes taking into account the family background characteristics and family income. In particular, we wanted to know whether the mother's job characteristics (working full-time or part-time, being in a job with unusual schedules, working in a low skill job

Pierre Lefebvre; Philip Merrigan

1998-01-01

352

Characterization of Neonatal Personnel Time Inputs and Prediction From Clinical Variables — A Time and Motion Study  

Microsoft Academic Search

OBJECTIVE: To characterize and predict personnel time inputs to neonatal intensive care using infant characteristics from chart review.STUDY DESIGN: For 12 hours each day, observers timed all direct care, charting, discussions, and procedures for 154 infants. Time inputs were correlated with 40 infant characteristics and resource markers, as well as the Score for Neonatal Acute Physiology (SNAP) for that day

John A F Zupancic; Douglas K Richardson

2002-01-01

353

Time ephemeris  

NASA Astrophysics Data System (ADS)

The location-independent part of barycentric coordinate time and geocentric coordinate time (TCB-TCG), the difference between the two new time scales adopted by the IAU, was integrated numerically for three JPL planetary/lunar ephemerides; DE102, DE200, and DE245. The differences among these three integrations were mostly explained by the difference in the adopted constants of the ephemerides. It was shown that the post-Newtonian correction and the perturbation by asteroids are negligible except for the mean rate, LC. The comparison of these numerical integrations with the analytical formulas of Hirayama et al. (1987) and Fairhead & Bretagnon (1990) as well as their extended versions lead to the best estimate of LC as 1.480 826 845 7 x 10-8 + or - 1.0 x 10-17. Combining this with the recent value of the geoid potential in Bursa et al. (1992), we estimate the value of LB, the scale difference between TCB and terrestrial time (TT), as 1.550 519 748 x 10-8 + or - 4 x 10-17. This will be useful in converting the numerical values of some astronomical constants determined in the old IAU time scale barycentric dynamic time (TDB) to those in TCB. Also the paper will be useful when converting between TCB and TDB, i.e. the time scales themselves.

Fukushima, T.

1995-02-01

354

On Time  

NSDL National Science Digital Library

This online exhibit from a prominent American museum explores the character of time -- its impact on our daily lives and its ability to shape and reform human consciousness. The site is from the National Museum of American History and concentrates on how humans have measured time from 1700 to the present. The exhibit presents text and images describing the history of keeping time from the century immediately preceding the industrial revolution -- when sundials were still in use -- to our present age of digital access and a global village that never sleeps.

355

Characteristics of thermosiphon reboilers  

Microsoft Academic Search

The paper describes the operational characteristics of thermosiphon reboilers on the basis of an experimental and theoretical study. The operational responses to a variation of the driving temperature difference, the operating pressure and the liquid head in the inlet line are discussed in detail. Furthermore, the influence of several design parameters as length and diameter of the pipes is presented.

Stephan Arneth; Johann Stichlmair

2001-01-01

356

Characteristics of risky play  

Microsoft Academic Search

This paper explores what makes children's risky play risky. Risky play can generally be defined as thrilling and exciting forms of play that involve a risk of physical injury. Few, if any, studies have been conducted to explore what identifies play activity as risky. The present study aims to determine what characteristics to judge risky play by. Risky play in

Ellen Beate Hansen Sandseter

2009-01-01

357

CHARACTERISTICS OF POLYPHENOL OXIDASES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Polyphenol oxidase (PPO, EC 1.14.18.1 or EC 1.10.3.1) catalyzes the oxidation of o-diphenols to o-quinones. Highly reactive o-quinones couple with phenolics and specific amino acids on proteins to form the characteristic browning products in many wounded fruits, vegetables, and leaf tissues of plant...

358

Study of Collision Characteristics.  

National Technical Information Service (NTIS)

Data on the details of 134 collisions were collected from the files of IMCO and USCG from 1944 to 1975. Cases are identified by number or name, flag, type, tonnage and characteristics. Information lists repair costs, location of casualty, weather, cause o...

A. S. Zahn

1977-01-01

359

Wave Types and Characteristics  

NSDL National Science Digital Library

This module is an introduction to waves and their associated characteristics. Several types of waves are presented, from the common wind wave to the rare tsunami wave. The basic physical, mathematical, and statistical traits of waves are discussed, along with how they change once waves become swell. This material serves as a building block to subsequent modules on wave generation, propagation, and dissipation.

Spangler, Tim

2003-07-01

360

Characteristics of Anchor Tests.  

ERIC Educational Resources Information Center

|The purpose of this study was twofold: to investigate to what extent characteristics of anchor tests may affect precision of item calibration, and to estimate to what extent precision of item calibration may be affected by removal of persons whose response patterns deviate from those normally expected from the Rasch one-parameter logistic model.…

Chang, S. Tai; Bashaw, W. L.

361

Characteristics of European basins  

Microsoft Academic Search

Hydrocarbon characteristics of some sedimentary basins in Europe are displayed by a series of transparent overlays. Combinations of these overlays provide rapid information on existing relationships among basin type, tectonic framework, exploratory effort, source and reservoir rocks, cumulative production, remaining recoverable reserves, and licensed areas as of January 1, 1988. Data were processed from Petroconsultants' data base and plotted on

B. M. Popescu; T. Orasianu

1988-01-01

362

Creative Time  

NSDL National Science Digital Library

Creative Time curates, funds, and organizes public art projects, so their website is a reference of the form dating back to 1975. You can browse by program name, date or artist's name (the most common of these being "multiple artists.") Creative Time's roster also includes familiar names such as Marina Abramovic, Doug Aitken, Laurie Anderson, David Byrne, Paul Chan, Jenny Holzer, Gary Hume, Vik Muniz, Takashi Murakami, Shirin Neshat, Steve Powers, and Cai Guo-Qiang. For example, Creative Time worked with Cai Guo-Qiang to present Light Cycle, in 2003, to celebrate the 150th anniversary of New York City's Central Park; in 2008 David Byrne's Playing the Building transformed the Battery Maritime Building in Lower Manhattan into a massive sound sculpture that visitors could play using a keyboard; and in summer 2012 Creative Time and multiple artists hosted a sandcastle competition at Far Rockaway, possibly the start of a new New York summer tradition.

2012-08-31

363

Real time automated inspection  

DOEpatents

A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

Fant, Karl M. (Minneapolis, MN); Fundakowski, Richard A. (Saint Paul, MN); Levitt, Tod S. (Minneapolis, MN); Overland, John E. (Plymouth, MN); Suresh, Bindinganavle R. (New Brighton, MN); Ulrich, Franz W. (Minneapolis, MN)

1985-01-01

364

Analysis on the Characteristics of URL Spam  

Microsoft Academic Search

E-mail is used by hundreds of millions of users every day because it constitutes a reliable, fast, and free media of communication. Nevertheless, huge amounts of spam are being generated and waste significant internet resources, as well as users' time. Spammer send advertised URL addresses at a massive scale. However, the characteristics of URL addresses through spam have not been

Wang Zhongtao; Peng Xin; Wang Yuling; Luo Yaohua; Huang Li; Cai Biao

2012-01-01

365

Observed characteristics of sudden commencement absorption  

Microsoft Academic Search

Ionospheric absorption at high latitudes that occurs coincidently with storm sudden commencements (SSC) is categorised as sudden commencement absorption (SCA). Having discounted any solar activity effects on the measurement of SCA this paper describes, for the first time, the basic characteristics of SCA measured over half a solar cycle.It is revealed that the measurement of SCA is not affected by

S. E. Ritchie; F. Honary

2009-01-01

366

Synoptic Controls on Boundary-Layer Characteristics  

Microsoft Academic Search

We report the characteristics of the three-dimensional, time evolving, atmospheric boundary layer that develops beneath an idealised, dry, baroclinic weather system. The boundary-layer structure is forced by thermal advection associated with the weather system. Large positive heat fluxes behind the cold front drive a vigorous convective boundary layer, whereas moderate negative heat fluxes in the warm sector between the cold

Victoria A. Sinclair; Stephen E. Belcher; Suzanne L. Gray

2010-01-01

367

Adult Learner Characteristics and Instructional Objectives.  

ERIC Educational Resources Information Center

|Using 40 male and 40 female part time learners with an average age of 36.6, this program planning study explored relationships between selected learner characteristics and behaviorally stated cognitive instructional objectives (IOs). Variables included age, sex, socioeconomic status, verbal ability, and a measure of learners' goals or learning…

Etter, David Campbell George

368

Human hand impedance characteristics during maintained posture  

Microsoft Academic Search

The present paper examines human hand impedance characteristics, including inertia and viscosity as well as stiffness, in multi-joint arm movements. While a subject maintains a given hand location, small external disturbances are applied to his hand by a manipulandum. The corresponding force-displacement vectors are measured and sampled over time in order to estimate the hand impedance by means of a

Toshio Tsuji; Pietro G. Morasso; Kazuhiro Goto; Koji Ito

1995-01-01

369

EVALUATION OF DRIVERS' CHARACTERISTICS IN MOSUL  

Microsoft Academic Search

In this work, a study of drivers' characteristics and behavior as important elements in the Highway system in Mosul was conducted. A questionnaire was designed to tap the following areas: driver education, experience, exposure (km driven and time), and accident experience. Three hundred individuals between 18-65 years of age were selected for the test program. Such driver individuals included male

Saad Issa Sarsam

370

The Essential Characteristics of Academic Advisors  

ERIC Educational Resources Information Center

What started as an activity valued for its oversight, the work of academic advisors have become a means leading to other ends, such as retention, student engagement, student satisfaction, persistence, and time to degree. The purpose of this research was to identify the essential characteristics of academic advisors; this was achieved by asking a…

Ward, Mary L.

2011-01-01

371

Characteristic and Ehrhart Polynomials  

Microsoft Academic Search

Let A be a subspace arrangement and let ?(A,t) be the characteristic polynomial of its intersection lattice L( A). We show that if the subspaces in A are taken from \\u000a$${\\\\mathcal{L}}({\\\\mathcal{B}}_n)$$\\u000a, where \\u000a$${\\\\mathcal{B}}_n$$\\u000a is the type B Weyl arrangement, then ?(A,t) counts a certain set of lattice points. One can use this result to study the partial factorization of

Andreas Blass; Bruce E. Sagan

1998-01-01

372

Cold Front Characteristics  

NSDL National Science Digital Library

In this activity, students will study animations of several atmospheric variables (air temperature, dew point, solar radiation, rainfall, and wind) to investigate the characteristics of weather produced by a cold front passage. Working in small groups, they will view animations from two different cases, identify patterns and changes, and answer questions about what they see. Links to a student worksheet, to the animations, and to viewing software are provided.

373

Characteristics of healthcare wastes  

SciTech Connect

A comprehensive understanding of the quantities and characteristics of the material that needs to be managed is one of the most basic steps in the development of a plan for solid waste management. In this case, the material under consideration is the solid waste generated in healthcare facilities, also known as healthcare waste. Unfortunately, limited reliable information is available in the open literature on the quantities and characteristics of the various types of wastes that are generated in healthcare facilities. Thus, sound management of these wastes, particularly in developing countries, often is problematic. This article provides information on the quantities and properties of healthcare wastes in various types of facilities located in developing countries, as well as in some industrialized countries. Most of the information has been obtained from the open literature, although some information has been collected by the authors and from reports available to the authors. Only data collected within approximately the last 15 years and using prescribed methodologies are presented. The range of hospital waste generation (both infectious and mixed solid waste fractions) varies from 0.016 to 3.23 kg/bed-day. The relatively wide variation is due to the fact that some of the facilities surveyed in Ulaanbaatar include out-patient services and district health clinics; these facilities essentially provide very basic services and thus the quantities of waste generated are relatively small. On the other hand, the reported amount of infectious (clinical, yellow bag) waste varied from 0.01 to 0.65 kg/bed-day. The characteristics of the components of healthcare wastes, such as the bulk density and the calorific value, have substantial variability. This literature review and the associated attempt at a comparative analysis point to the need for worldwide consensus on the terms and characteristics that describe wastes from healthcare facilities. Such a consensus would greatly facilitate comparative analyses among different facilities, studies and countries.

Diaz, L.F. [CalRecovery, Inc., Concord, California (United States)], E-mail: ludiaz@calrecovery.com; Eggerth, L.L. [CalRecovery, Inc., Concord, California (United States); Enkhtsetseg, Sh. [Ministry of Health, Ulaanbaatar (Mongolia); Savage, G.M. [CalRecovery, Inc., Concord, California (United States)

2008-07-01

374

Characteristics of Danish estuaries  

Microsoft Academic Search

We review various aspects of the structure and functioning of Danish estuaries from data collected by the National Monitoring\\u000a Program and from information in published sources. We present data on the physical, chemical, and biological characteristics\\u000a of estuaries in Denmark, we evaluate the functioning of these systems as filters and transformers of nutrients and we evaluate\\u000a the outlook for Danish

Daniel J. Conley; Hanne Kaas; Flemming Møhlenberg; Bjarke Rasmussen; Jørgen Windolf; Flemming Mohlenberg; Jorgen Windolf

2000-01-01

375

Characteristics of potential repository wastes  

SciTech Connect

The Office of Civilian Radioactive Waste Management (OCRWM) is responsible for the spent fuels and other wastes that will be disposed of in a geologic repository. The two major sources of these materials are commercial light-water reactor (LWR) spent fuel and immobilized high-level waste (HLW). Other wastes that may require long-term isolation include non-LWR spent fuels and miscellaneous sources such as activated metals. Detailed characterizations are required for all of these potential repository wastes. These characterizations include physical, chemical, and radiological properties. The latter must take into account decay as a function of time. This information has been extracted from primary data sources, evaluated, and assembled in a Characteristics Data Base which provides data in four formats: hard copy standard reports, menu-driven personal computer (PC) data bases, program-level PC data bases, and mainframe computer files. The Characteristics Data Base provides a standard set of self-consistent data to the various areas of responsibility including systems integration and waste stream analysis, storage, transportation, and geologic disposal. The data will be used for design studies, evaluation of alternatives, and system optimization by OCRWM and supporting contractors. 7 refs., 5 figs., 7 tabs.

Notz, K.J.

1989-01-01

376

Geologic Time  

NSDL National Science Digital Library

This site contains 24 questions on the topic of geologic time, which covers dating techniques and unconformities. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate feedback.

Heaton, Timothy

377

Reaction Time  

NSDL National Science Digital Library

This lab is not an inquiry activity. There are some students whose reaction times will not allow them to catch a 12 inch ruler. They may use a dowel, stick, strip of cardboard, etc. Although the students are led to believe that the point of the lab is to

Horton, Michael

2009-05-30

378

Number Time  

ERIC Educational Resources Information Center

|This article features Number Time, a site developed by the British Broadcasting Corporation (BBC) for young mathematics learners, located at www.bbc.co.uk/schools/numbertime. The site uses interactive animation to help children in pre-K through grade 2 understand and practice number basics. Users will find online games, videos that tell number…

Herrera, Terese A.

2004-01-01

379

Geologic Time.  

ERIC Educational Resources Information Center

|Discusses the historical development of the concept of geologic time. Develops the topic by using the major discoveries of geologists, beginning with Steno and following through to the discovery and use of radiometric dating. An extensive reference list is provided. (JM)|

Albritton, Claude C., Jr.

1984-01-01

380

Deep Time  

NSDL National Science Digital Library

In this video a Penn State professor refers to National Park canyons carved out by water and wind as he explains “deep time” - the notion that the earth is billions of years old; another professor states how the theory of evolution is supported by evidence of an ancient Earth recorded in rocks.

Wpsu

2010-05-04

381

Pulsar Timing Arrays  

NASA Astrophysics Data System (ADS)

In the last decade, the use of an ensemble of radio pulsars to constrain the characteristic strain caused by a stochastic gravitational wave background has advanced the cause of detection of very low frequency gravitational waves (GWs) significantly. This electromagnetic means of GW detection, called Pulsar Timing Array (PTA), is reviewed in this paper. The principle of operation of PTA, the current operating PTAs and their status are presented along with a discussion of the main challenges in the detection of GWs using PTA.

Joshi, Bhal Chandra

2013-01-01

382

Discovering salient characteristics of authors of artworks  

NASA Astrophysics Data System (ADS)

We addressed the problem of finding salient characteristics of artists from two-dimensional (2D) images of historical artifacts. Given a set of 2D images of historical artifacts by known authors, we discovered what salient characteristics made an artist different from others, and then enabled statistical learning about individual and collective authorship. The objective of this effort was to learn what would be unique about the style of each artist, and to provide the quantitative results about salient characteristic. We accomplished this by exploring a large search space of low level image descriptors. The motivation behind our framework was to assist humanists in discovering salient characteristics by automated exploration of the key image descriptors. By employing our framework we had not only saved time of art historians but also provided quantitative measures for incorporating their personal judgments and bridging the semantic gap in image understanding. We applied the framework implementation to the face illustrations in Froissart's Chronicles drawn by two anonymous authors. We reported the salient characteristics to be (HSV, histogram, k-nearest neighbor) among the 55 triples considered with 5-fold validations. These low level characteristics were confirmed by the experts to correspond semantically to the face skin colors.

Bajcsy, Peter; Moslemi, Maryam

2010-02-01

383

Time Traveler  

NSDL National Science Digital Library

This NOVA website simulates travel to distant stars and back in a spaceship that can move at various percentages of the speed of light. You set the spaceship speed and choose your destination star, and the simulation calculates the time of travel as measured on Earth and inside the spaceship. Text describes the "twin paradox" of the theory of relativity and also the 1971 test of its prediction using airliners and atomic clocks.

2011-10-15

384

Exploring nonlinear characteristics in seismogenic process  

NASA Astrophysics Data System (ADS)

Power spectral characteristics of the seismic activities before and after the seven large earthquake — Haicheng, Tangshan, Lancang, Longling, Mabian, Puer and Songpan are studied by spectrum analysis method. The results show that they all have continuous power spectrum and aperiodic behaviour. When the time away from the large earthquake occurrence, the characteristics of the seismic activities are obviously accompanied by stochastic components. About one year before main shock, the moving orbits constructed by spectrum amplitudes showed the contracting tendency. And the properties during that time may display as flicker noise. One’s another time almost mixed whole phase space. But the essence of seismic activities after main shocks is a chaotic state accompanied with much noises.

An, Zhen-Wen; Wang, Lin-Ying; Chen, Yao; Pan, Han-Meng

1993-11-01

385

Fibre Optic Sensors for Selected Wastewater Characteristics  

PubMed Central

Demand for online and real-time measurements techniques to meet environmental regulation and treatment compliance are increasing. However the conventional techniques, which involve scheduled sampling and chemical analysis can be expensive and time consuming. Therefore cheaper and faster alternatives to monitor wastewater characteristics are required as alternatives to conventional methods. This paper reviews existing conventional techniques and optical and fibre optic sensors to determine selected wastewater characteristics which are colour, Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD). The review confirms that with appropriate configuration, calibration and fibre features the parameters can be determined with accuracy comparable to conventional method. With more research in this area, the potential for using FOS for online and real-time measurement of more wastewater parameters for various types of industrial effluent are promising.

Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

2013-01-01

386

Scaling characteristics in the Taiwan stock market  

NASA Astrophysics Data System (ADS)

Some statistical tools, including histogram, spectral analysis and fractal theory, were used on the daily Taiwan stock price index (TSPI) from 1987 to 2002 to examine the possible scale-invariant behavior and the clustering characteristics in Taiwan stock market. It was found that the TSPI data exhibited the characteristic of right-skewed frequency distribution. The long-term memory and the possibility of scale invariance were roughly identified through the analysis of autocorrelation and power spectrum, respectively. The monofractal analysis was then performed by the box-counting method. Scale invariance was clearly found in the time series and the box dimension was shown to be a decreasing function of the threshold index level, implying multifractal characteristics, i.e., the low and high regions scale differently. To test this hypothesis, the time series were transferred into a useful compact form through the multifractal formalism, namely, the ?(q)-q and f(?)-? plots. The analysis confirmed the existence of multifractal characteristics in the investigated time series. The origin of multifractal phenomena in Taiwan stock market might be interpreted in terms of the multiplicative cascade process of stock market information.

Ho, Ding-Shun; Lee, Chung-Kung; Wang, Cheng-Cai; Chuang, Mang

2004-02-01

387

Modelling fundamental waiting time distributions for earthquake sequences  

Microsoft Academic Search

The distribution of waiting times between time-neighbouring events for a time series obeying the Omori law is examined theoretically and numerically with the aim of understanding the characteristics of these distributions, how these characteristics change (e.g. scale) with the parameters of the Omori series, and thus how empirical waiting time data may be correctly interpreted. It is found that the

Kristin Jonsdottir; Mattias Lindman; Roland Roberts; Björn Lund; Reynir Bödvarsson

2006-01-01

388

Times Square  

NSDL National Science Digital Library

This interactive online game helps students develop fluency with multiplication facts as well as strategic thinking. The goal is to claim four numbers in a row (vertically, horizontally, or diagonally) on a 6 by 6 game board displaying the products of one-digit numbers. Players take turns moving one of the two factor markers to claim a product on the board before time runs out. This game is part of NCTM's Calculation Nation project. Users may login as a guest and play against the computer, or register (free) to challenge other players online.

2010-01-01

389

Adjoint analysis for receptivity prediction  

Microsoft Academic Search

Physical knowledge of the laminar-turbulent transition process, prediction of the transition location, as well as the ability to control transition are essential in many engineering applications. However, control of the laminar-turbulent transition depends critically on various environmental sources and their ability to excite the instability waves in the flow, which are responsible for the laminar-turbulent transition. The process by which

Alexander Y. Dobrinsky

2003-01-01

390

Characteristics of Business Owners Survey  

NSDL National Science Digital Library

The Census Bureau has released the results of the 1992 Characteristics of Business Owners Survey (CBO). These results provide data for comparing the "selected economic, demographic, and sociological characteristics" of business owners.

1997-01-01

391

[UPLC characteristic chromatographic profile of Poria].  

PubMed

To establish a UPLC characteristic chromatographic profile analysis method to quickly assess Poria quality and provide basis fro controlling Poria quality. The UPLC characteristic chromatographic profiles of fifteen batches of Poria were determined by ACQUITY UPLC, with HSS T3 Column (2.1 mm x 100 mm, 1.8 microm) eluted with the mobile phases of water containing 0.05% phosphoric acid and acetonitrile in gradient mode. The detection wavelength was set at 243 nm. The common mode of the UPLC characteristic chromatographic profile was set up. There were 20 common peaks, seven of which were identified, and the similar degrees of the fifteen samples to the common mode were between 0.787 and 0.974. The method was so time-saving that it can be used for the quality control of Poria. PMID:22792799

Zhang, Qi; Wang, Zhenzhong; Xiao, Wei; Zhang, Liangqi; Bi, Kaishun; Jia, Ying

2012-04-01

392

Wafer characteristics via reflectometry  

SciTech Connect

Various exemplary methods (800, 900, 1000, 1100) are directed to determining wafer thickness and/or wafer surface characteristics. An exemplary method (900) includes measuring reflectance of a wafer and comparing the measured reflectance to a calculated reflectance or a reflectance stored in a database. Another exemplary method (800) includes positioning a wafer on a reflecting support to extend a reflectance range. An exemplary device (200) has an input (210), analysis modules (222-228) and optionally a database (230). Various exemplary reflectometer chambers (1300, 1400) include radiation sources positioned at a first altitudinal angle (1308, 1408) and at a second altitudinal angle (1312, 1412). An exemplary method includes selecting radiation sources positioned at various altitudinal angles. An exemplary element (1650, 1850) includes a first aperture (1654, 1854) and a second aperture (1658, 1858) that can transmit reflected radiation to a fiber and an imager, respectfully.

Sopori, Bhushan L. (Denver, CO)

2010-10-19

393

Characteristics of tau oligomers.  

PubMed

In Alzheimer disease (AD) and other tauopathies, microtubule-associated protein tau becomes hyperphosphorylated, undergoes conformational changes, aggregates, eventually becoming neurofibrillary tangles (NFTs). As accumulating evidence suggests that NFTs themselves may not be toxic, attention is now turning toward the role of intermediate tau oligomers in AD pathophysiology. Sarkosyl extraction is a standard protocol for investigating insoluble tau aggregates in brains. There is a growing consensus that sarkosyl-insoluble tau correlates with the pathological features of tauopathy. While sarkosyl-insoluble tau from tauopathy brains has been well characterized as a pool of filamentous tau, other dimers, multimers, and granules of tau are much less well understood. There are protocols for identifying these tau oligomers. In this mini review, we discuss the characteristics of tau oligomers isolated via different methods and materials. PMID:23882258

Ren, Yan; Sahara, Naruhiko

2013-07-19

394

Early Adolescents: Their Developmental Characteristics.  

ERIC Educational Resources Information Center

Discussed are major developmental characteristics of 10 to 15-year olds. These characteristics are organized around the developmental, social, behavioral processes within early adolescents. It is suggested they are taking on the characteristics of older adolescents of the 1970s, involved in their own lives and in the decisions affecting them.…

Thornburg, Hershel D.

1980-01-01

395

Anthropometric characteristics evolution in elite rhythmic gymnasts.  

PubMed

The aims of this research were to assess anthropometric characteristics of high-level senior and junior rhythmic gymnasts; and was to investigate the changes of anthropometric characteristics over a 4 years period, in different senior and junior groups of the same technical level. Twenty anthropometric variables of 63 participants were collected and body composition and sitting-height-to-stature-ratio measures were calculated. The two-way (gymnast category and time) ANOVA of the anthropometric characteristics showed significant main effect of time period for biacromial and bicristal diameters indicating that the majority of variables had similar values in 2002 and 2006. A significant main effect of category (junior or senior) was present in most the analyzed variables with higher values in senior gymnasts than juniors. The significant category by time interaction for height, weight, limbs' length, and fat-free mass, indicated that some differences between junior and senior gymnasts increased over the 4 yr time period. The training hours per week were significantly higher in seniors, but did not differ over the 4 yr period. The study shows that the criteria, followed for the recruitment of elite gymnasts, in the two different periods considered (2002 and 2006) were almost the same. Moreover, higher differences between seniors and juniors of FFM values in 2006 indicated the more intensive training of the second period for seniors. PMID:18491452

di Cagno, Alessandra; Baldari, Carlo; Battaglia, Claudia; Guidetti, Laura; Piazza, Marina

396

Rheological and fracture characteristics of low penetration grade bitumen  

Microsoft Academic Search

Interest in the rheological and fracture characteristics of low penetration grade bitumens has increased in recent times due to greater use of progressively stiffer base materials and the growing concern over the durability of these extremely hard, high stiffness modulus materials. This paper investigates the high and low temperature rheological characteristics, tensile fracture modes and cohesive properties of a series

Gordon D. Airey; Young K. Choi; Andrew C. Collop; Richard Elliott

2004-01-01

397

Direct simulation of pumping characteristics for a model diffusion pump  

Microsoft Academic Search

The pumping characteristics of a single\\/multi-stage diffusion pump were simulated using the Direct Simulation Monte Carlo (DSMC) method. The hard sphere model is used as a molecular model and the No Time Counter (NTC) scheme is employed as a collision sampling technique. Steady state flow characteristics such as velocity, temperature, density distributions of the pumped gas and oil vapor are

YK Lee; JW Lee

1996-01-01

398

Video Game Structural Characteristics: A New Psychological Taxonomy  

ERIC Educational Resources Information Center

|Excessive video game playing behaviour may be influenced by a variety of factors including the structural characteristics of video games. Structural characteristics refer to those features inherent within the video game itself that may facilitate initiation, development and maintenance of video game playing over time. Numerous structural…

King, Daniel; Delfabbro, Paul; Griffiths, Mark

2010-01-01

399

The Study of Driver Distraction Characteristic Detection Technology  

Microsoft Academic Search

Driver's distraction in driving is one of the major causes of the traffic accidents. The abnormal behavior of the driver's head movement and the facial expressions were studied in detail in order to get the characteristics of the inattention status. With real-time monitoring on the driver's attention characteristics: the position and movement status information of eyes and mouth, the detection

Liu Zhiqiang; Wang Peng; Zhong Jingjing

2010-01-01

400

Management Reviewing Literature: An Evaluation of Selected Characteristics.  

ERIC Educational Resources Information Center

Reports results of a study which compared the treatment of selected characteristics of the reviewing literature of management in professional and trade journals. The characteristics examined included lag time, review length, descriptive or analytic nature of reviews, positive or negative evaluations, and affiliation of the reviewer. (CLB)

Rehman, Sajjad ur

1987-01-01

401

Twitch characteristics in relation to muscle architecture and actual muscle length  

Microsoft Academic Search

The length dependence of twitch time characteristics is quantified for several skeletal muscles of the rat: lateral gastrocnemius, medial gastrocnemius, plantaris, soleus and semimembranosus. It is shown that muscle architecture influences the length dependent behaviour of twitch time characteristics of muscles. Twitch contraction time is less susceptible to length changes of the muscles than the twitch relaxation time. With the

R. D. Woittiez; P. A. Huijing; R. H. Rozendal

1984-01-01

402

14 CFR 417.221 - Time delay analysis.  

Code of Federal Regulations, 2010 CFR

...following: (1) The variance of all time delays for each potential failure...malfunction turn characteristics and the time of flight when the malfunction occurs...safety official's decision and reaction time, including variation in human...

2010-01-01

403

14 CFR 417.221 - Time delay analysis.  

Code of Federal Regulations, 2010 CFR

...following: (1) The variance of all time delays for each potential failure...malfunction turn characteristics and the time of flight when the malfunction occurs...safety official's decision and reaction time, including variation in human...

2009-01-01

404

Importance timing  

NASA Astrophysics Data System (ADS)

Bayesian evidence Z = ? L(x)d?(x) is defined as likelihood L integrated over prior ?, and is often computed in that form -- with nested sampling as the preferred algorithm for passing from prior to posterior in large or complicated applications. However, a user may suspect that some locations x are more useful than others, and wish to guide the computation by using a suitable weight function w(x). In conventional importance sampling, such weights are incorporated by re-writing Z as ?(L/w)(wd?), using a weighted prior w? and correspondingly de-weighted likelihood L/w. Unfortunately, w cannot be updated during a run without altering the likelihood surfaces (which nested sampling requires to be fixed). Also, the normalization ? wd? must be known if the value of Z is to be retrieved. Importance timing removes those disadvantages by preserving the likelihood unchanged. Excess prior weight w is cancelled, not through L, but by adjusting the rate of the MCMC clock which defines termination of a trial exploration. This preserves the evidence value and enables the weights to be (slowly) learned as iterations proceed.

Skilling, John

2013-08-01

405

Doing Time  

PubMed Central

Once convicted, the perpetrator of serious crime embarks upon a new journey: the challenge of adjusting to long-term imprisonment. Prisoners’ views of incarceration and the meaning of this experience may affect their later adjustment to life in the community. On the basis of brief narrative responses collected during an epidemiological survey of the psychological health of prisoners in France, this study examined the impact of incarceration on psychological state in a group of 59 inmates serving long sentences. Qualitative content analysis and computer-assisted linguistic analysis (using ALCESTE software) were performed on the textual data of open responses to three standard questions. Using a combination of these two approaches, seven categories of the subjective experience of prisoners in the sample were identified: the Outside World, Others, Punishment, Time, Affects and Impulses, Self-Concept, and Speech. Further qualitative analyses were then performed to compare the responses of Severely Mentally Ill (SMI) subjects and subjects with no psychiatric disorder. These analyses revealed contrasting attitudes towards incarceration. SMI subjects spoke in more hostile and persecutory terms about their experience in prison, attributing suffering to external circumstances, while subjects with no psychiatric disorder evoked similar themes, but with an introspective attitude. The themes evoked by mentally ill individuals in our sample suggest that their reactions to the prison environment arise in part from aspects of their psychiatric symptoms, and this may have relevance to future mental health policy and practices in criminal corrections.

Yang, Suzanne; Kadouri, Alane; Revah-Levy, Anne; Mulvey, Edward P.; Falissard, Bruno

2009-01-01

406

Cosmic Times  

NSDL National Science Digital Library

This series of curriculum support materials and classroom activities explores how our understanding of the nature of the Universe has changed during the past 100 years. Students examine the process of science through the stories of the people and the discoveries that caused our understanding to evolve from a static universe to a Universe whose expansion is accelerating. The series illustrates the nature of science by tracing the process of discovery from the confirmation of Einsteinâs theory of gravity, to Hubbleâs evidence for the expanding Universe, to the detection of the microwave background, and finally to the discovery of dark energy. The series includes six posters, each resembling the front page of a newspaper from a particular time in this history with articles describing the discoveries. Each poster is accompanied by an on-line teacher guide and 4-5 downloadable, inquiry-based lessons, which teach the science, the process of science, and skills for science literacy. Two downloadable âNewsletterâ versions of the poster are available for individual student use: one with the same text as on the poster, while the second uses text at a lower reading level.

Lochner, James

2010-02-16

407

Pulsar Searching and Timing  

NASA Astrophysics Data System (ADS)

More than 2000 pulsars are now known. These pulsars may be divided into a number of different classes according to their period, period derivative, binary properties, emission characteristics and so on. Some important classes have relatively few members, e.g. double-neutron-star binary systems, and so continued searches for currently unknown pulsars are important. Such searches are being undertaken at various observatories around the world. Somewhat unexpectedly, the Fermi Gamma-ray Observatory, has proved to be an efficient pulsar detector, especially for millisecond pulsars (MSPs). The great stability of pulsar periods, especially for MSPs, leads to a number of important applications of pulsar timing. The detection and study of relativistic orbit perturbations in double-neutron-star systems has proved to be a powerful tool with measurements of the original binary pulsar, PSR B1913+16, and more recently the double pulsar, PSR J0737-3039A/B, showing that Einstein's general theory of relativity accurately describes these gravitational interactions. Direct detection of gravitational waves using pulsar timing is close to being achieved with the development of pulsar timing arrays (PTAs) in Europe, North America and Australia. Combining data from these PTAs to form the International Pulsar Timing Array (IPTA) will lead to improved significance of such a detection. Ultimately, detailed study of gravitational-wave sources will be possible using future large radio telescopes such as FAST and the SKA.

Manchester, R. N.

2013-01-01

408

Teacher Retention: Teacher Characteristics, School Characteristics, Organizational Characteristics, and Teacher Efficacy  

ERIC Educational Resources Information Center

|The researcher utilized block-entry regression analysis to determine the impacts of teacher characteristics, school characteristics, organizational characteristics, and teacher efficacy on retention in teaching from 782 teacher surveys. Findings indicated that 83.50% of participants planned to teach until retirement. Wald statistics indicated…

Hughes, Gail D.

2012-01-01

409

Coping mechanisms of part?time students  

Microsoft Academic Search

A characteristic shared by the majority of adult students is that they are undertaking part?time study. For these adult learners one of the major difficulties is how to find time for their study. This paper reports the coping mechanisms that part?time adult students adopt to meet the additional demands that study puts on their existing commitments to work, family and

Jessie C. K. Yum; David Kember; Irene Siaw

2005-01-01

410

Channel holding time in hierarchical cellular systems  

Microsoft Academic Search

We study the characteristics of the channel holding time in the multitier cellular systems supporting overflow and underflow schemes with the general call holding time and the general cell residence time. Comparison between our results, together with previous results, and simulation shows that our result is more universal and more accurate.

Yan Zhang; Boon-Hee Soong

2004-01-01

411

Seismic Pulses Derivation from the Study of Source Signature Characteristics  

SciTech Connect

This paper deals with a deterministic technique for the derivation of seismic pulses by the study of source characteristics. The spectral characteristics of the directly or the nearest detected seismic signal is analyzed and considered as the principle source signature. Using this signature seismic pulses are derived with accurate time position in the seismic traces. The technique is applied on both synthetic and field refraction seismic traces. In both cases it has estimated that the accurate time shifts along with amplitude coefficients.

Rahman, Syed Mustafizur; Nawawi, M. N. Mohd.; Saad, Rosli [School of Physics, Univeristi Sains Malaysia, 11800 USM, Pulau Pinang (Malaysia)

2010-07-07

412

Principles of Time-of-Flight Tomography.  

National Technical Information Service (NTIS)

After a short introduction to the physics of time-of-flight positron tomography, the various aspects of this technique are presented. The characteristics including data acquisition and image reconstruction system of a positron tomograph (TTV01) which uses...

R. Campagnolo P. Garderet J. L. Lecomte A. Bouvier P. Darier

1983-01-01

413

Motorcycle helmet ventilation and heat transfer characteristics  

Microsoft Academic Search

1. Abstract Heat transfer characteristics of 10 motorcycle helmets were measured. Each helmet was tested three times on a manikin headform placed in a climate chamber (22 ºC and 50% RH) at the exit of a wind tunnel (50 ± 1.1 km·h-1). In every measurement a helmet was evaluated with the ventilation openings closed and open. Heat transfer ( Q&

C. P. Bogerd; P. A. Brühwiler

414

Synoptic Controls on Boundary-Layer Characteristics  

Microsoft Academic Search

We report the characteristics of the three-dimensional, time evolving, atmospheric boundary layer that develops beneath an\\u000a idealised, dry, baroclinic weather system. The boundary-layer structure is forced by thermal advection associated with the\\u000a weather system. Large positive heat fluxes behind the cold front drive a vigorous convective boundary layer, whereas moderate\\u000a negative heat fluxes in the warm sector between the cold

Victoria A. Sinclair; Stephen E. Belcher; Suzanne L. Gray

2010-01-01

415

Dynamic relaxation characteristics of Matrimid ® polyimide  

Microsoft Academic Search

The dynamic relaxation characteristics of Matrimid® (BTDA–DAPI) polyimide have been investigated using dynamic mechanical and dielectric methods. Matrimid exhibits three motional processes with increasing temperature: two sub-glass relaxations (? and ? transitions), and the glass—rubber (?) transition. The low-temperature ? transition is purely non-cooperative, and displays an identical time–temperature response to both the dynamic mechanical and the dielectric probes with

Anthony C. Comer; Douglass S. Kalika; Brandon W. Rowe; Benny D. Freeman; Donald R. Paul

2009-01-01

416

Weak characteristics of muonium  

SciTech Connect

The allowed weak decay channels of muonium are studied in detail. They acquire additional significance in the context of possible {ital M}-{ital {bar M}} oscillations that probe beyond the standard model. The muonium decay rate and annihilation rate are found to be 1.000 023 and 1.045{times}10{sup {minus}10}, respectively, in units of the free muon decay rate.

Chatterjee, L.; Chakrabarty, A.; Das, G.; Mondal, S. (Physics Department, Jadavpur University, Calcutta 32 (India))

1992-12-01

417

Physical characteristics of sand injectites  

NASA Astrophysics Data System (ADS)

Almost two hundred years of research is reviewed that focuses on the physical characteristics of sandstone intrusions. It is concerned with mechanisms of sand injection, particularly with fluid-grain transport and sedimentation processes during the remobilization, injection and extrusion of sand. Outcrop and subsurface studies in combination with laboratory experimental data are drawn on to present the state-of-the-art of sand injection. The text covers 1) geometry, internal structure, and microtexture of deformed parent units, injected and extruded sandstones, 2) host-strata and their seal characteristics that contribute to basin-wide overpressure generation, 3) common trigger mechanisms for sand injection such as high magnitude seismicity and the rapid injection of large volumes of fluids, 4) fluid types that drive sand into fractures, 5) hydrofracture mechanisms that induce regional-scale seal failure, 6) liquefaction and fluidization processes that transport sand into fractures, 7) sedimentation processes in fractures, 8) the flow regime of fluidized sand during injection, 9) post-sand-injection fluid flow and diagenesis, 10) porosity and permeability characteristics of injected sandstones and 11) post-sand-injection fluid-flow over geological timescales. Processes of sand remobilization, injection, and extrusion are complex and depend on many interrelated factors including: fluid(s) properties (e.g. pressure, volume, composition), parent unit and host-strata characteristics (e.g. depositional architecture, grain size and distribution, clay-size fraction, thickness, permeability) and burial depth at the time of injection. Many studies report erosional contacts between host strata and injected sands and these record high-velocity, erosive flow during injection. The flow regime is poorly constrained and similar features are interpreted as records of laminar and turbulent flow, or both, during injection. Internal structures are common in sandstone intrusions and can be accounted for by a variety of processes. The interpretational limits largely result from a lack of laboratory experiments that focus on developing analogues for sand injection. The relationship between grain fabric developed during injection and its control on permeability in sandstone intrusions is poorly understood and failure to advance this field of research will hinder the quantitative characterization of sandstone intrusions as fluid-flow conduits during basin evolution. We conclude that future research should focus on: 1) quantification of sediment transport modes under different flow conditions in different fracture dimensions with laboratory data relevant to sand injection; 2) estimation of the effect of injection on the bulk permeability of otherwise low-permeability seals (host strata) so that their effect on fluid flow can be assessed at all scales; and 3) incorporation of sand injection into quantitative basin models. Although an enormous amount of data have arisen from existing studies there remains a need to advance many fields of research related to sand injection so that the significance of these important structures can be fully appreciated in the geological record.

Hurst, Andrew; Scott, Anthony; Vigorito, Mario

2011-06-01

418

Computer calculations of PIN diode limiter characteristics  

NASA Astrophysics Data System (ADS)

Characteristics of microwave limiters, especially those of spike leakage and burnout, although little understood, are of great importance to the high-power microwave community. The Harry Diamond Laboratories computer program DIODE has been used to simulate limiter action. This is the first time the basic physical mechanisms of a limiter diode have been studied by a computer program. Simulations have included silicon PIN diode widths of from 0.5 to 10 um, applied frequencies of 200 MHz to 50 GHz, and applied powers of 0.5 to 800 W. Illustrative carrier concentrations and electric fields are given as a function of distance across the diode and as a function of time, and diode and limiter output powers are given as a function of time. There is a frequency range where the limiter output power increases approximately linearly with frequency, which is the dependence predicted by linear theory. Avalanche breakdown during the reverse half-cycle is calculated for high-input powers. Limiter characteristics are shown to be strongly dependent upon diode temperature. calculations, limiter characteristics, silicon, forward bias, reverse switching, recombination lifetime, PIN diode and microwaves.

Ward, Alford L.

1987-09-01

419

Structure of chymopapain M the late-eluted chymopapain deduced by comparative modelling techniques and active-centre characteristics determined by pH-dependent kinetics of catalysis and reactions with time-dependent inhibitors: the Cys-25/His-159 ion-pair is insufficient for catalytic competence in both chymopapain M and papain.  

PubMed Central

Chymopapain M, the monothiol cysteine proteinase component of the chymopapain band eluted after chymopapains A and B in cation-exchange chromatography, was isolated from the dried latex of Carica papaya and characterized by kinetic and chromatographic analysis. This late-eluted chymopapain is probably a component of the cysteine proteinase fraction of papaya latex discovered by Schack [(1967) Compt. Rend. Trav. Lab. Carlsberg 36, 67-83], named papaya peptidase B by Lynn [(1979) Biochim. Biophys. Acta 569, 193-201] and partially characterized by Polgár [(1981) Biochim. Biophys. Acta 658, 262-269] and is the enzyme with unusual specificity characteristics (papaya proteinase IV) that Buttle, Kembhavi, Sharp, Shute, Rich and Barrett [Biochem. J. (1989) 261, 469-476] claimed to be a previously undetected cysteine proteinase eluted from a cation-exchange column near to the early-eluted chymopapains. A study of the time-dependent chromatographic consequences of thiol-dependent proteolysis of the components of papaya latex is reported. Chymopapain M was isolated by (i) affinity chromatography followed by separation from papain using cation-exchange f.p.l.c. on a Mono S HR5/5 column and (ii) cation-exchange chromatography followed by an unusual variant of covalent chromatography by thiol-disulphide interchange. The existence in chymopapain M of a nucleophilic interactive Cys/His catalytic-site system analogous to those in papain (EC 3.4.22.2) and other cysteine proteinases was deduced from the characteristics shape of the pH-second-order rate constant (k) profiles for its reactions with 2,2'-dipyridyl disulphide and ethyl 2-pyridyl disulphide. Analysis of the pH-k data for the reactions of chymopapain M with the 2-pyridyl disulphides and with 4,4'-dipyridyl disulphide permits the assignment of molecular pKa values of 3.4 and 8.7 to the formation and subsequent dehydronation of the Cys-S-/His-Im+H state of the catalytic site and reveals three other kinetically influential ionizations with pKa values 3.4, 4.3 and 5.6. The pH-dependences of kcat./Km for the hydrolysis of N-acetyl-L-Phe-Gly-4-nitroanilide at 25.0 degrees C and I0.1 M catalysed by chymopapain M and papain were determined. For both enzymes, little catalytic activity (5-7% of the maximal) develops consequent on formation of the catalytic site Cys-S-/His-Im+H ion-pair state (across pKa 3.4 for both enzymes). For papain, full expression of Kcat./Km for the uncharged substrate requires only the additional hydronic dissociation with pKa 4.2. By contrast, full expression of kcat./Km for chymopapain M requires additional hydronic dissociation with pKa values of 4.3 and 5.6.(ABSTRACT TRUNCATED AT 400 WORDS) Images Figure 6 Figure 7

Thomas, M P; Topham, C M; Kowlessur, D; Mellor, G W; Thomas, E W; Whitford, D; Brocklehurst, K

1994-01-01

420

Material characteristics of titanium:sapphire  

SciTech Connect

Nonexponential decay of the {sup 2}{ital E} level of Ti:Al{sub 2}O{sub 3} at 300 K is reported for the first time to the authors' knowledge. A decay time of 5.5 {mu}sec at 15 {mu}sec after excitation was observed in Ti:Al{sub 2}O{sub 3} samples prepared by different growth methods as compared with 3.2 {mu}sec observed initially. Correlations of the nonexponential decay characteristics with the laser figure of merit and crystal homogeneity are presented. A simple and nondestructive crystal diagnostic method is proposed.

Gu, B.; Birnbaum, M. (Center for Laser Studies, University of Southern California, Los Angeles, California 90089-1112 (USA)); Leong, B. (Northrop Electronics Division, Hawthorne, California 90251 (USA))

1989-12-01

421

Explosive Characteristics of Carbonaceous Nanoparticles  

NASA Astrophysics Data System (ADS)

Explosion testing has been performed on 20 codes of carbonaceous particles. These include SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes), CNFs (carbon nanofibers), graphene, diamond, fullerene, carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226-10 protocol), at a (dilute) concentration of 500 g/m^3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples exhibited overpressures of 5-7 bar, and deflagration index KSt = V^1/3 (dp/pt)max ˜ 10 - 80 bar-m/s, which places these materials in European Dust Explosion Class St-1 (similar to cotton and wood dust). There was minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with particle size (BET specific surface area). Additional tests were performed on selected materials to identify minimum explosive concentration [MEC]. These materials exhibit MEC ˜ 10^1 -10^2 g/m^3 (lower than the MEC for coals). The concentration scans confirm that the earlier screening was performed under fuel-rich conditions (i.e. the maximum over-pressure and deflagration index exceed the screening values); e.g. the true fullerene KSt ˜ 200 bar-m/s, placing it borderline St-1/St-2.

Turkevich, Leonid; Fernback, Joseph; Dastidar, Ashok

2013-03-01

422

Characteristics Data Base  

SciTech Connect

The LWR Serial Numbers Database System (SNDB) contains detailed data about individual, historically discharged LWR spent fuel assemblies. This data includes the reactor where used, the year the assemblies were discharged, the pool where they are currently stored, assembly type, burnup, weight, enrichment, and an estimate of their radiological properties. This information is distributed on floppy disks to users in the nuclear industry to assist in planning for the permanent nuclear waste repository. This document describes the design and development of the SNDB. It provides a complete description of the file structures and an outline of the major code modules. It serves as a reference for a programmer maintaining the system, or for others interested in the technical detail of this database. This is the initial version of the SNDB. It contains historical data through December 31, 1987, obtained from the Energy Information Administration (EIA). EIA obtains the data from the utility companies via the RW-859 Survey Form. It evaluates and standardizes the data and distributes the resulting batch level database as a large file on magnetic tape. The Characteristics Data Base obtains this database for use in the LWR Quantities Data Base. Additionally, the CDB obtains the individual assembly level detail from EIA for use in the SNDB. While the Quantities Data Base retains only the level of detail necessary for its reporting, the SNDB does retain and use the batch level data to assist in the identification of a particular assembly serial number. We expect to update the SNDB on an annual basis, as new historical data becomes available.

Lewis, E.D.; Moore, R.S. (Automated Sciences Group, Inc., Oak Ridge, TN (USA))

1990-08-01

423

Three-dimensional modeling of diesel engine intake flow, combustion and emissions-II  

SciTech Connect

A three-dimensional computer code, KIVA, is being modified to include state-of-the-art submodels for diesel engine flow and combustion. Improved and/or new submodels which have already been implemented and previously reported are: Wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo`vich NO{sub x}, and spray/wall impingement with rebounding and sliding drops. Progress on the implementation of improved spray drop drag and drop breakup models, the formulation and testing of a multistep kinetics ignition model and preliminary soot modeling results are described in this report. In addition, the use of a block structured version of KIVA to model the intake flow process is described. A grid generation scheme has been developed for modeling realistic (complex) engine geometries, and computations have been made of intake flow in the ports and combustion chamber of a two-intake-valve engine. The research also involves the use of the code to assess the effects of subprocesses on diesel engine performance. The accuracy of the predictions is being tested by comparisons with engine experiments. To date, comparisons have been made with measured engine cylinder pressure, temperature and heat flux data, and the model results are in good agreement with the experiments. Work is in progress that will allow validation of in-cylinder flow and soot formation predictions. An engine test facility is described that is being used to provide the needed validation data. Test results have been obtained showing the effect of injection rate and split injections on engine performance and emissions.

Reitz, R.D.; Rutland, C.J.

1993-09-01

424

Time scales in fragmentation  

SciTech Connect

The problem of fragmentation of excited finite systems is explored in the frame of classical molecular dynamics experiments of two-dimensional Lennard-Jones drops. The main objective of this work is to get information about the relative value of the relevant characteristic time scales (CTS) for this kind of process. We investigate the CTS for fragment formation, the stabilization of the radial flux, and the internal {open_quotes}temperature.{close_quotes} It is found that the asymptotic fragments are realized early in phase space, when the system is still dense, by the time the radial flux attains its asymptotic value. It is also shown that the temperature of the system during the breakup is quite homogenous with respect to the expected profile if local thermal equilibration takes place. Special emphasis is put on the investigation of the time scale of stabilization of the statistical properties of the mass spectrum, which is related to the kind of information carried by the asymptotic fragments. {copyright} {ital 1997} {ital The American Physical Society}

Strachan, A.; Dorso, C.O. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellon I, Ciudad Universitaria, Nunez 1428, Buenos Aires (Argentina)

1997-02-01

425

Characteristics of Ethical Business Cultures  

Microsoft Academic Search

The purpose of this study was to identify general characteristics attributed to ethical business cultures by executives from\\u000a a variety of industries. Our research identified five clusters of characteristics: Mission- and Values-Driven, Stakeholder\\u000a Balance, Leadership Effectiveness, Process Integrity, and Long-term Perspective. We propose that these characteristics be\\u000a used as a foundation of a comprehensive model that can be engaged to

Alexandre Ardichvili; James A. Mitchell; Douglas Jondle

2009-01-01

426

Residential-appliance load characteristics  

NASA Astrophysics Data System (ADS)

The performance of residential photovoltaic systems in combination with energy efficient appliances is examined. The load characteristics are presented for several types of major residential appliances. Load characteristics consist of the average energy use of each appliance, the power demand while the appliance is operating, and a typical use schedule. Potential energy conserving features are investigated for each appliance and used to identify a best available model and maximum feasible energy efficient appliance. Load characteristics of these energy conserving designs are then compared with the load characteristics of a standard model. The feasibility of converting appliances to dc power for use with photovoltaic systems is also discussed.

Kohler, J.

1982-04-01

427

Voice characteristics of acromegaly.  

PubMed

Acromegaly's effect on voice is still indefinite. We aimed to define acoustic characteristics of patients with acromegaly. Cross-sectional case-control study was designed. Thirty-seven patients with acromegaly and 30 age- and sex-matched healthy controls were included. Fundamental frequency (F0) and measurements related to frequency, amplitude, noise and tremor of the obtained voice sample were analyzed using Multi-Dimensional Voice Program. Absolute jitter (Jita) and jitter percent (Jitt), shimmer in decibel and shimmer percent, noise to harmonic ratio and soft phonation index, fundamental frequency tremor frequency and frequency tremor intensity index represented the parameters related to frequency, amplitude, noise and tremor of the voice sample, respectively. Patients with acromegaly, especially the uncontrolled patients, exhibited significant differences in frequency perturbation measurements. Jitt of all patients and Jita of uncontrolled patients were significantly higher than that of control group (p = 0.044 and p = 0.043, respectively). Jitter which is a measure of frequency perturbation can be assumed as an indicator of hoarse and deepened voice. Jita of all patients and Jitt of uncontrolled patients were elevated, but not reaching a statistical significance. Controlled and active patients had similar analysis of acoustic parameters. In the correlation analysis, shimmer and IGF-1 (insulin like growth factor 1) was found to be positively correlated in all patients with acromegaly and in female patients. When the p value is adjusted according to Bonferroni correction regarding the use of ten parameters for acoustic analysis (so adjusted p is <0.005), all the statistically significant findings become insignificant. Considering the parameters test different properties of voice, it is reasonable to pay attention to the findings. Patients with acromegaly have increased frequency perturbations measures, but this increase is non-significant according to Bonferroni correction. This may be perceptually sensed as hoarse voice. Amplitude perturbations within the voice of the patients with acromegaly are positively correlated with IGF-1 levels, this correlation is also non-significant according to Bonferroni correction. PMID:23389327

Aydin, Kadriye; Turkyilmaz, Didem; Ozturk, Burak; Dagdelen, Selcuk; Ozgen, Burce; Unal, Faruk; Erbas, Tomris

2013-02-07

428

Spectroscopic characteristics of polar plumes  

NASA Astrophysics Data System (ADS)

Extreme ultraviolet observations of plumes in polar coronal holes are presented and their spectroscopic signatures discussed. The study focuses on the base of plumes seen on the disk of the Sun with the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) satellite. Spectroscopic diagnostic techniques are applied to characterise the plumes in terms of density, temperature, emission measure and element abundance. Attention is drawn to the particular limitations of some of the techniques when applied to plume structures. In particular, we revisit the Widing & Feldman (1992) findings of a plume having a large first ionization potential (FIP) effect of 10, showing that instead the Skylab data are consistent with no FIP effect. We present for the first time CDS-GIS (grazing incidence spectrometer) observations of a plume. These observations have been used to confirm the results obtained from normal incidence (NIS) observations. We find that polar plumes exhibit the same characteristics as the Elephant's Trunk equatorial plume. The most striking characteristic of the plume bases is that they are near-isothermal with a peak emission measure at transition region temperatures =~ 8 x 105 K. At these temperatures, plumes have averaged densities Nlo {e} =~ 1.2 x 109 cm-3, about twice the value of the surrounding coronal hole region. Element abundances in the plumes are found to be close to photospheric, with the exception of neon which appears to be depleted by 0.2 dex relative to oxygen. The absence of a significant FIP effect in plumes is consistent with fast solar wind plasma, although it is not sufficient to prove a link between the two. Finally, we present a comparison between GIS spectra and the SOHO EIT (EUV Imaging Telescope) broad-band images, showing that temperatures derived from the EIT ratio technique are largely overestimated, for plumes and coronal holes. This is partly due to the fact that the so called ``Fe XII 195 Å'' and ``Fe XV 284 Å'' filters are not isothermal, and in coronal holes and plumes lower-temperature lines dominate the EIT signal.

Del Zanna, G.; Bromage, B. J. I.; Mason, H. E.

2003-02-01

429

Cattaraugus Creek Characteristics  

NSDL National Science Digital Library

Students start this exercise using topographic maps of an area recently visited on a field trip to calculate and consider stream gradient of a major river south of Buffalo, NY. The activity then changes gears to have students work with discharge measurements from this stream. They use these measurements to plot and evaluate a few hydrographs which are used to compare how discharge in this stream can be used to consider how much precipitation was received in a certain year. In this lab, students practice mathematically calculating geomorphic properties of a stream, plotting data, and comparing topographic maps to what they observed on the recent field trip. Designed for a geomorphology course Uses online and/or real-time data Addresses student fear of quantitative aspect and/or inadequate quantitative skills

Williams, Kevin

430

Characteristics of Black Postsecondary Students.  

ERIC Educational Resources Information Center

A profile is presented of the social and economic characteristics of black students, 16 years old and over, enrolled in college or a noncollegiate postsecondary institution, based on data from the U.S. Census Bureau's 1976 Survey of Income and Education. After a reviewing of characteristics of the black population in the United States in the…

Hill, Susan; And Others

431

Evaluator Characteristics and Methodological Choice  

ERIC Educational Resources Information Center

|This study addresses the central question "How do evaluators' background characteristics relate to their evaluation design choices?" Evaluators were provided with a fictitious description of a school-based program and asked to design an evaluation of that program. Relevant background characteristics such as level of experience, methodological…

Azzam, Tarek

2011-01-01

432

Combustion characteristics of boron nanoparticles  

Microsoft Academic Search

An experimental investigation of the combustion characteristics of boron nanoparticles in the post flame region of a flat flame burner has been conducted. Boron is attractive as a fuel or a fuel supplement in propellants and explosives due to its high heats of combustion on both a gravimetric and volumetric basis. A relatively large database exists for combustion characteristics of

Gregory Young; Kyle Sullivan; Michael R. Zachariah; Kenneth Yu

2009-01-01

433

Perceptual Characteristics of Female Voices.  

ERIC Educational Resources Information Center

Male and females listeners rated 21 young female voices on seven scales representing unique vocal features. Voices were described as "passive", or traditionally female, and "active," characterized as "lively,""colorful," and "sexy." Females found active characteristics more salient; males preferred the passive characteristics. Implications for…

Batstone, Susan; Tuomi, Seppo K.

1981-01-01

434

Behavior characteristics of schizophrenic children  

Microsoft Academic Search

Summary Eight prominent behavior characteristics of schizophrenic and schizoid children have been enumerated as the result of prolonged observation of 14 such patients in a children's neuropsychiatric hospital. A working definition of the various characteristics is presented, and the significance of each is discussed. The results of the study should clarify the diagnosis of childhood schizophrenia and furnish the basis

Charles Bradley; Margaret Bowen

1941-01-01

435

Perceptual Characteristics of Female Voices.  

ERIC Educational Resources Information Center

|Male and females listeners rated 21 young female voices on seven scales representing unique vocal features. Voices were described as "passive", or traditionally female, and "active," characterized as "lively,""colorful," and "sexy." Females found active characteristics more salient; males preferred the passive characteristics. Implications for…

Batstone, Susan; Tuomi, Seppo K.

1981-01-01

436

Teachers' Job Characteristics and Motivation.  

ERIC Educational Resources Information Center

|To test the Job Characteristics Model of Motivation, 247 Quebec teachers completed the Job Diagnostic Survey. Results demonstrated the utility of the model and the instrument for the teaching profession. Psychological states influenced the relationship between job characteristics and motivation/satisfaction outcomes. (SK)|

Barnabe, Clermont; Burns, Mildred

1994-01-01

437

Transient characteristics of rocket turbopumps  

Microsoft Academic Search

Transient characteristics of high-speed, high-pressure cryogenic turbopumps for rocket engines were examined experimentally by starting and stopping several rocket turbopumps rapidly by gas turbine drive. Aspects of transient characteristics studied were instantaneous pump head coefficient and pump efficiency, cavitation growth in the inducer during rapid acceleration, effects of the starting mode related to the propulsion system mission, and transient behavior

Takashi Shimura; Mitsuo Watanabe

1990-01-01

438

General characteristics of civil forfeiture  

Microsoft Academic Search

Purpose – This paper attempts to clarify and describe the general characteristics of civil forfeiture as a new national and international tool in the fight against organized crime. Design\\/methodology\\/approach – The paper analyzes and compares the civil forfeiture legislations of five counties – the USA, Great Britain, Ireland, Bulgaria and Serbia and draws conclusions on the general characteristics of this

Nikolay Nikolov

2011-01-01

439

Evolution of Sunspot Characteristics in Cycle 23  

NASA Astrophysics Data System (ADS)

The aim of this work is to present a statistical study of several parameters (variables) that define sunspot groups. These variables include maximum area, growth and decay times, as well as the evolution families, and solar-cycle phase the groups belong to. We classified group types based on the Zurich classification, which allows us to define a set of families based on their evolution patterns. The time variation of the area of a group was also studied, and a relationship between the maximum area and the growth and decay times was sought. Another study was carried out to find the correlation among different characteristics of the groups, as well as how the probability of a certain value of decay time can vary depending on morphological characteristics defined by these variables. Thus, a program based on a weight matrix combining the variables necessary to classify a group, together with the calculation of the probability for a specific event, has been produced. This approach allows us to predict the future behavior of a group from its historical evolution.

Gómez, A.; Curto, J. J.; Gras, C.

2013-06-01

440

Analysis of reflectance characteristics of selected plants  

NASA Astrophysics Data System (ADS)

The paper presents reflectance characteristics of plants. The objects of the research were the selected plants, taking the various levels of organization and structure into consideration, as well as the state of plant health and growth. Reflectance spectrum was analyzed in the range of wavelengths from 0,2 to 2,5 ?m. The values of reflectance for three wavelengths (?1=850 nm, ?2=905 nm, ?3=1550 nm) were analyzed with the particular emphasis. The sample tests were performed immediately after biological material taking and in the several 24-hour time intervals. The time intervals enabled the process of plants wilting and drying. The reflectance measurements were repeated until the moment of plant complete dried out. All measurements were performed with the use of the spectrometer Lambda 900 (Perkin Elmer) equipped with the 150 mm integrating sphere PELA1001 dedicated for the measurements of the hemispherical reflectance both of diffuse and specular type. On the basis of the obtained results one calculated the values of signal ratios for the three selected wavelengths: 850/1550nm, 905/1550nm, and 850/905nm. The collected spectra and reflectance characteristics enabled the analyses of both results similarities and differences, which enabled the determination of the reflectance changes tendency associated with the typical processes occurring in plants. The analyses of plants reflectance characteristics were made for the use of the laser system for identification of terrain elements and their physico-chemical properties.

Kaszczuk, Miroslawa; Mierczyk, Zygmunt; Zygmunt, Marek; Piotrowski, Wieslaw; Mierczyk, Jadwiga

2011-05-01

441

Characteristics of a numerical fluid dynamics simulator  

NASA Astrophysics Data System (ADS)

A concept of a real time Numerical Fluid Dynamics Simulator (NFDS) is described, and its characteristics are derived. The following characteristics are adopted as guiding principles: (1) that the performance characteristics (information output, throughput and storage) of the NFDS be defined by the maximum rate at which the research can absorb the results of his/her simulator, thus establishing an impedance match between man and machine; (2) that the NFDS off-load from the researcher's brain in every way possible the routine tasks of data analysis that can be done automatically; and (3) that the NFDS is operated as a dedicated experimental device and that the researcher has complete control over the apparatus and experiment. The NFDS is envisioned to be composed of simulation processors, data storage devices, and image processing devices of extremely high power and capacity, interconnected by very high throughput communication channels. Individual component performance requirements are presented for both real time and playback operating models of the NFDS, using problems of current interest in fluid dynamics as examples.

Winkler, K. H. A.; Norman, M. L.; Norton, J. L.

1985-08-01

442

Influences of preparation technology on the flashover characteristics of machinable ceramics in vacuum  

Microsoft Academic Search

This paper probes into the influences of preparation technology, mainly crystallization time, on the flashover characteristics of machinable ceramics under 0.4\\/2.5 mus impulse voltage in vacuum. Several machinable ceramic samples are prepared with the same procedure under different crystallization time. To study the association between crystallization time and flashover characteristics, the surface microstructures of samples are observed by SEM, while

Guo-Qing Liu; Kai-Kun Yu; Jie Tian; Guan-Jun Zhang

2008-01-01

443

A hierarchical bayesian statistical framework for response time distributions  

Microsoft Academic Search

This paper provides a statistical framework for estimating higher-order characteristics of the response time distribution, such as the scale (variability) and shape. Consideration of these higher order characteristics often provides for more rigorous theory development in cognitive and perceptual psychology (e.g., Luce, 1986). RT distribution for a single participant depends on certain participant characteristics, which in turn can be thought

Jeffrey N. Rouder; Dongchu Sun; Paul L. Speckman; Jun Lu; Duo Zhou

2003-01-01

444

Measuring spatial variability in soil characteristics  

DOEpatents

The present invention provides systems and methods for measuring a load force associated with pulling a farm implement through soil that is used to generate a spatially variable map that represents the spatial variability of the physical characteristics of the soil. An instrumented hitch pin configured to measure a load force is provided that measures the load force generated by a farm implement when the farm implement is connected with a tractor and pulled through or across soil. Each time a load force is measured, a global positioning system identifies the location of the measurement. This data is stored and analyzed to generate a spatially variable map of the soil. This map is representative of the physical characteristics of the soil, which are inferred from the magnitude of the load force.

Hoskinson, Reed L. (Rigby, ID); Svoboda, John M. (Idaho Falls, ID); Sawyer, J. Wayne (Hampton, VA); Hess, John R. (Ashton, ID); Hess, J. Richard (Idaho Falls, ID)

2002-01-01

445

Wild times and domesticated times: the temporalities of environmental lifestyles and politics  

Microsoft Academic Search

In this paper, I explore how environmental movements and lifestyles, like all forms of human action, produce their own characteristic kinds of time. During this exploration, I introduce a number of concepts which I suggest are useful in understanding these temporalities—chronological and kairological time; linear and cyclic time; segmentation and plot; orientation and synchronisation. Whereas the environment as described by

Bronislaw Szerszynski

2002-01-01

446

The Physical Characteristics of Minerals  

NSDL National Science Digital Library

Offered by Amethyst Galleries, Inc. (an online minerals store), the Physical Characteristics of Minerals Web site offers a detailed description of how minerals are identified. Each page gives good information and examples of a particular characteristic (e.g, color, hardness, cleavage, feel, and taste). Also, on the first page are links to dozens of minerals that are categorized by name, class, interesting groupings, and great localities. These give the class, subclass, group, uses, physical characteristics, and sample photographs of that particular mineral. Anyone interested in geology, minerals, or gemstones will find this site very informative and fun to explore.

1998-01-01

447

Multiridge detection and time-frequency reconstruction  

Microsoft Academic Search

The ridges of the wavelet transform, the Gabor transform, or any time-frequency representation of a signal contain crucial information on the characteristics of the signal. Indeed, they mark the regions of the time-frequency plane where the signal concentrates most of its energy. We introduce a new algorithm to detect and identify these ridges. The procedure is based on an original

R. A. Carmona; Wen L. Hwang; B. Torresani

1999-01-01

448

Time Travellers: Adventure to the Archaean  

NSDL National Science Digital Library

In this activity, students play the roles of time travelers and travel to the Archaean era to learn what early Earth was like during that time. They collect information on the Archaean atmosphere, life forms, and landscape, and write a report that summarizes its characteristics. A scoring rubric for the report is provided.

Weaver, Marion

449

Cyclostationary in the Time Variable Universe  

Microsoft Academic Search

Cyclostationary processes are those signals whose have vary almost periodically in statistics. It can give rise to random data whose statistical characteristics vary periodically with time although these processes not periodic functions of time. Intermittent pulsar is a special type in pulsar astronomy which have period but not a continuum. The Rotating RAdio TransientS (RRATs) represent a previously unknown population

Jiang Dong; Yun Nan

2009-01-01

450

Predicting application run times with historical information  

Microsoft Academic Search

We present a technique for predicting the run times of parallel applications based upon the run times of “similar” applications that have executed in the past. The novel aspect of our work is the use of search techniques to determine those application characteristics that yield the best definition of similarity for the purpose of making predictions. We use four workloads

Warren Smith; Ian T. Foster; Valerie E. Taylor

2004-01-01