These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Numerical simulation of laminar-turbulent transition in a spatially-developing flat plate wake  

Microsoft Academic Search

Laminar-turbulent transition of an incompressible flat-plate wake is investigated by direct numerical integration of the Navier-Stokes equations. For the numerical integration, a combination of finite-difference and spectral methods along with an ADI\\/Crank-Nicolson\\/Adams-Bashforth time integration scheme is employed. Subject to 2D forcing, the wake exhibited a rapidly-growing fundamental disturbance that quickly saturated. This saturation was due partly to the stabilizing effect

D. I. Dratler; H. F. Fasel

1993-01-01

2

Laminar-turbulent transition prediction module for LOGOS package  

NASA Astrophysics Data System (ADS)

The present work is devoted to a description and substantiation of an original module for computing the location of laminar-turbulent transition in subsonic boundary layer flows, which is based on the e N -method and enables more accurate computations of the flow around bodies in the presence of the so-called natural transition to turbulence in the boundary layer. A combined work of the module and the RANS solver from the aerodynamic part of the LOGOS package is demonstrated by the example of the flow past a flat plate. The obtained computed locations of the beginning and the end of the laminar-turbulent transition coincide with known reference values.

Boiko, A. V.; Nechepurenko, Yu. M.; Zhuchkov, R. N.; Kozelkov, A. S.

2014-04-01

3

Laminar-Turbulent Transition: The Change of the Flow State Temperature with the Reynolds Number  

NASA Astrophysics Data System (ADS)

Using the previously developed model to describe laminar/turbulent states of a viscous fluid flow, which treats the flow as a collection of coherent structures of various size (Chekmarev, Chaos, 2013, 013144), the statistical temperature of the flow state is determined as a function of the Reynolds number. It is shown that at small Reynolds numbers, associated with laminar states, the temperature is positive, while at large Reynolds numbers, associated with turbulent states, it is negative. At intermediate Reynolds numbers, the temperature changes from positive to negative as the size of the coherent structures increases, similar to what was predicted by Onsager for a system of parallel point-vortices in an inviscid fluid. It is also shown that in the range of intermediate Reynolds numbers the temperature exhibits a power-law divergence characteristic of second-order phase transitions.

Chekmarev, Sergei F.

2014-09-01

4

Oblique laminar-turbulent interfaces in plane shear flows.  

PubMed

Localized structures such as turbulent stripes and turbulent spots are typical features of transitional wall-bounded flows in the subcritical regime. Based on an assumption for scale separation between large and small scales, we show analytically that the corresponding laminar-turbulent interfaces are always oblique with respect to the mean direction of the flow. In the case of plane Couette flow, the mismatch between the streamwise flow rates near the boundaries of the turbulence patch generates a large-scale flow with a nonzero spanwise component. Advection of the small-scale turbulent fluctuations (streaks) by the corresponding large-scale flow distorts the shape of the turbulence patch and is responsible for its oblique growth. This mechanism can be easily extended to other subcritical flows such as plane Poiseuille flow or Taylor-Couette flow. PMID:23373928

Duguet, Yohann; Schlatter, Philipp

2013-01-18

5

Nonlinear transient growth and detecting the laminar-turbulent boundary  

NASA Astrophysics Data System (ADS)

The area of transition to turbulence has experienced a spurt of activity recently in wall-bounded shear flows where transition is triggered by finite amplitude disturbances. This has been stimulated by the discovery of new solutions to the governing equations which are disconnected from the steady unidirectional ``base'' flow in, for example, pipe flow and plane Couette flow. Understanding how all this new (nonlinear) work fits together with transient growth ideas which focus on linear mechanisms based around the base state presents an interesting challenge. In this talk, we attempt to bridge the gap from linear optimals to the (very nonlinear) laminar-turbulent boundary in phase space which determines whether a given disturbance will trigger turbulence or not.

Kerswell, Rich; Pringle, Chris

2009-11-01

6

Hypersonic laminar–turbulent transition on circular cones and scramjet forebodies  

Microsoft Academic Search

Laminar–turbulent transition in hypersonic boundary layers has a dramatic effect on heat transfer, skin friction, and separation. This effect is critical to reentry vehicles and airbreathing cruise vehicles, yet the physics of the transition process is not yet well enough understood to be used for predictive purposes. The literature for transition on circular cones and scramjet forebodies is reviewed, from

Steven P. Schneider

2004-01-01

7

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

2013-06-01

8

Supersonic quiet-tunnel development for laminar-turbulent transition research  

NASA Technical Reports Server (NTRS)

This grant supported research into quiet-flow supersonic wind-tunnels, between February 1994 and February 1995. Quiet-flow nozzles operate with laminar nozzle-wall boundary layers, in order to provide low-disturbance flow for studies of laminar-turbulent transition under conditions comparable to flight. Major accomplishments include: (1) development of the Purdue Quiet-Flow Ludwieg Tube, (2) computational evaluation of the square nozzle concept for quiet-flow nozzles, and (3) measurement of the presence of early transition on the flat sidewalls of the NASA LaRC Mach 3.5 supersonic low-disturbance tunnel. Since items (1) and (2) are described in the final report for companion grant NAG1-1133, only item (3) is described here. A thesis addressing the development of square nozzles for high-speed, low-disturbance wind tunnels is included as an appendix.

Schneider, Steven P.

1995-01-01

9

On the role of secondary instabilities in laminar-turbulent transition of 2D and 3D boundary layers  

NASA Technical Reports Server (NTRS)

The accurate prediction of laminar/turbulent transition is one of the fundamental problems in engineering fluid mechanics. There is almost unanimous consent that such a transition criterion should come from stability theory. Linear primary stability theory describes the initial stage of transition, but falls short of predicting transition. Only in conjunction with empirical correlations, the widely used e(sup n) method is obtained, which, however, lacks a solid physical base. Three-dimensional secondary instabilities are known to play an important role in the transition process. However, no use has been made so far of secondary instabilities, instability interactions or wave resonances to define a 'transition location'. The paper summarizes new attempts to identify certain interaction and resonance phenomena within the laminar-turbulent transition regime in two and three-dimensional boundary layers which are associated with rapid structural and temporal changes of fluctuations beyond their exponential growths.

Dallman, Uwe; Fischer, Thomas M.; Koch, Werner; Bippes, Hans

1992-01-01

10

Constrained large-eddy simulation of laminar-turbulent transition in channel flow  

NASA Astrophysics Data System (ADS)

A constrained large-eddy simulation (CLES) of a laminar-turbulent transition in a temporally developing channel flow is performed. First, we confirm the capability of CLES to simulate this transition problem using the a priori Reynolds stress estimated from a direct numerical simulation. Based on the analysis of the Reynolds stress during the transition process, an intermittency factor is introduced in the Reynolds-averaged Navier-Stokes equation (RANS) model to account for the transition property. Two simple approaches are used to construct the intermittency factor. One is based on the shape factor, and the other is based on the coefficients of Smagorinsky models. The CLES results using the intermittency modified RANS model can accurately predict the onset of the transition and the basic transition process, in a manner similar to a large eddy simulation with dynamics Smagorinsky model (LES-DSM). Meanwhile, CLES preserves its advantage over LES-DSM in the turbulent state. The present work illustrates that CLES can be used to simulate transitional flows.

Zhao, Yaomin; Xia, Zhenhua; Shi, Yipeng; Xiao, Zuoli; Chen, Shiyi

2014-09-01

11

Development of quiet-flow supersonic wind tunnels for laminar-turbulent transition research  

NASA Technical Reports Server (NTRS)

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 transition under conditions comparable to flight. Major accomplishments include: (1) the design, fabrication, and performance-evaluation of a new kind of quiet tunnel, a quiet-flow Ludweig tube; (2) the integration of preexisting codes for nozzle design, 2D boundary-layer computation, and transition-estimation into a single user-friendly package for quiet-nozzle design; and (3) the design and preliminary evaluation of supersonic nozzles with square cross-section, as an alternative to conventional quiet-flow nozzles. After a brief summary of (1), a description of (2) is presented. Published work describing (3) is then summarized. The report concludes with a description of recent results for the Tollmien-Schlichting and Gortler instability in one of the square nozzles previously analyzed.

Schneider, Steven P.

1994-01-01

12

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

13

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

14

The effect of neutrally buoyant finite-size particles on channel flows in the laminar-turbulent transition regime  

NASA Astrophysics Data System (ADS)

The presence of finite-size particles in a channel flow close to the laminar-turbulent transition is simulated with the Force Coupling Method which allows two-way coupling with the flow dynamics. Spherical particles with channel height-to-particle diameter ratio of 16 are initially randomly seeded in a fluctuating flow above the critical Reynolds number corresponding to single phase flow relaminarization. When steady-state is reached, the particle volume fraction is homogeneously distributed in the channel cross-section (? ? 5%) except in the near-wall region where it is larger due to inertia-driven migration. Turbulence statistics (intensity of velocity fluctuations, small-scale vortical structures, wall shear stress) calculated in the fully coupled two-phase flow simulations are compared to single-phase flow data in the transition regime. It is observed that particles increase the transverse r.m.s. flow velocity fluctuations and they break down the flow coherent structures into smaller, more numerous and sustained eddies, preventing the flow to relaminarize at the single-phase critical Reynolds number. When the Reynolds number is further decreased and the suspension flow becomes laminar, the wall friction coefficient recovers the evolution of the laminar single-phase law provided that the suspension viscosity is used in the Reynolds number definition. The residual velocity fluctuations in the suspension correspond to a regime of particulate shear-induced agitation.

Loisel, Vincent; Abbas, Micheline; Masbernat, Olivier; Climent, Eric

2013-12-01

15

Laminar-turbulent flow around a wedge placed on sharp and blunted plates  

NASA Astrophysics Data System (ADS)

The flow structure and heat transfer on sharp and blunted plates near a wedge have been studied experimentally at Mach number 6 and two Reynolds numbers corresponding to laminar and transitional boundary layers ahead of the wedge. Similarly to the two-dimensional (2D) flow, the plate's blunting causes a decrease of heat transfer at threedimensional (3D) interference between the boundary layer and the shock wave. However, there is a threshold bluntness value beyond which the influence is negligible. Heat transfer and pressure measurements as well as surface flow visualization have been performed by means of panoramic (global) methods based on the use of luminescent coatings. They have been used in a short duration (pulse) wind tunnel for the first time.

Borovoy, V.; Mosharov, V.; Radchenko, V.; Noev, A.

2012-01-01

16

Studies of laminar-turbulent transition in air and in water wall pressure fluctuations and acoustic emission from the turbulent intermittency  

NASA Astrophysics Data System (ADS)

Experimental studies of the laminar-turbulent boundary layer transition were conducted with the same axisymmetric test body in air and in water. First results established a clear causal relation between turbulent intermittency and a very wide band (20 to 30 kHz), low level acoustic emission. Further experiments yielded observations of a natural transition region up to 11 m/s in water. Boundary layer instabilities at calculated longitudinal unstable frequencies were identified. In a higher frequency band, other 'unstable' frequencies were observed, which do not agree with laminar instability results. It is suspected that these higher frequencies are a consequence of small deformations of the body geometry. Near-field cross-spectral analyses also show the existence of an upstream acoustic radiation in water, covering a 20 kHz frequency band, whose source is not definitely identified.

Perraud, J. C.

17

Modeling bioaccumulation using characteristic times.  

PubMed

A new formulation of existing mass balance models for bioaccumulation is derived and applied to organisms that respire either water or air. This model employs characteristic time parameters and equations that are mathematically equivalent to those used in existing concentration-rate constant and fugacity models. The equivalence of these traditional formulations and the novel formulation is demonstrated. In all three formulations, the required information includes various physiological and dietary parameters as well as chemical concentrations in food and in the respired medium of water or air. Chemical properties are described by the octanol-water or octanol-air partition coefficient and a metabolic biotransformation half-life. Bioaccumulation, biomagnification, and all uptake and loss rates are expressed using characteristic times that have readily identifiable chemical or biological significance. The ability of the characteristic time formulation to provide an evaluation of the bioenergetic consistency of organism properties is briefly discussed. The model is applied illustratively to a trout as a water-respiring organism and to a wolf as an air-respiring organism, and the results are discussed. It is concluded that the use of characteristic time parameters and equations provides valuable additional insights regarding the relative importance of the various uptake and loss processes and, thus, is complementary to the conventional approaches for modeling bioaccumulation phenomena in a variety of organisms. PMID:18798695

Powell, Adrian; Mackay, Don; Webster, Eva; Arnot, Jon A

2009-02-01

18

Effect of free-stream turbulence properties on boundary layer laminar-turbulent transition: A new approach  

NASA Astrophysics Data System (ADS)

The effect of length scale on flat-plate by-pass transitional boundary layers subject to free stream turbulence intensities ranging from 1.3 to 6.0 percent has been investigated. The analysis is based on the recent experimental and numerical observations into non-equilibrium flows that considering the effect of turbulence properties at the plate leading edge on the transition onset. According to this analysis, physical correlation is developed and incorporated in a conventional boundary layer computer scheme for prediction of transitional flows. The scheme was proposed to calculate the characteristics of the boundary layers under the effect of moderate free-stream turbulence levels by enhancing established integral techniques in conjunction with intermittency weighted model of the transitional boundary layer. To support the results validation, the experimental ERCOFTAC Test Cases T3A, T3B and T3AM for transitional integral parameters have been represented. The results show that the transition location for turbulence level higher than 4% is only a function of turbulence intensity (Tu) and unaffected by significant changes in the length scale (Lx). Whereas for low level of the incoming turbulent flows the transition onset is extremely dependent on FST characteristics, turbulence intensity and integral length scale.

Darag, Sakhr A.; Horák, Vladimír

2012-11-01

19

CharacteristicBased Dissipative Schemes and Characteristic Time Stepping  

E-print Network

motivates a characteristic time stepping approach for steady state computations. For viscous applications appreciate the many contributions that Gigi Martinelli has made to my education in CFD over the last three : : : : : : : : : : : : : : : : : : 8 1.4 The Viscous Motivation : : : : : : : : : : : : : : : : : : : : : 9 1.5 The Present Approach

Pierce, Niles A.

20

Stroking Characteristics during Time to Exhaustion Tests  

Microsoft Academic Search

ALBERTY, M., M. SIDNEY, P. PELAYO, and H. M. TOUSSAINT. Stroking Characteristics during Time to Exhaustion Tests. Med. Sci. Sports Exerc., Vol. 41, No. 3, pp. 637-644, 2009. Purpose: Race analyses during swimming reveal how exercise duration affects both clean swimming speed (v), stroke rate (SR), and stroke length (SL). The aim of this study is to provide an explanation

MORGAN ALBERTY; MICHEL SIDNEY; PATRICK PELAYO; HUUB M. TOUSSAINT

2009-01-01

21

Studies of "Kapustinsky's" light pulser timing characteristics  

E-print Network

We present the results of studies of a nanosecond light pulser built following J.S.Kapustinsky et al original design and using bright InGaN/GaN ultraviolet and blue LEDs produced by NICHIA CHEMICAL. It is shown how timing characteristics of the pulser depend on the type of LED and the value of power supply voltage.

Lubsandorzhiev, B K

2006-01-01

22

Studies of "Kapustinsky's" light pulser timing characteristics  

E-print Network

We present the results of studies of a nanosecond light pulser built following J.S.Kapustinsky et al original design and using bright InGaN/GaN ultraviolet and blue LEDs produced by NICHIA CHEMICAL. It is shown how timing characteristics of the pulser depend on the type of LED and the value of power supply voltage.

B. K. Lubsandorzhiev; Y. E. Vyatchin

2004-10-29

23

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

24

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

25

Noise characteristics of LCOGT time series photometry  

NASA Astrophysics Data System (ADS)

The Las Cumbres Observatory Global Telescope (LCOGT) facility consists of a network of robotic telescopes located at multiple sites in both the northern and southern hemispheres. We have deployed and commissioned nine 1.0m telescopes. Eight of these are distributed longitudinally at three sites to provide continuous night-time coverage in the south. LCOGT's unique capabilities can contribute to a wide range of research in the field of time-domain astronomy. To ensure optimal data quality for individual as well as combined multi-telescope time series, it is essential that we understand and correct - whenever possible - the instrument systematics affecting LCOGT network observations. We identify physical sources of noise present in LCOGT 1.0m photometry, and we use singular value decomposition (SVD) to filter correlated noise patterns common to an ensemble of stars in a given time series data set. We quantify and compare the levels of uncorrelated and correlated noise before and after SVD filtering using power spectral analysis. Finally, we discuss the properties of and methods to reduce any remaining post-SVD red noise that is due to instrumental systematics.

Dragomir, Diana; Brown, T. M.

2014-01-01

26

[Study of time characteristics in spectrometer dynamic sampling].  

PubMed

The present paper uses the relationship between sawtooth wave's amplitude and time's linear code to test and analyze a spectrometer. The result shows that the sampling time is associated with the integration time and the sampling interval closely relates with integral time, and the fluctuation range of sampling interval was further explored. This paper provides the reference of the integral time for the analysis focused on spectrum time characteristic, proposes a method to evaluate the dynamic time properties, and contributes to the assessment and application of the dynamic characteristics of the spectrum. PMID:25007643

Xiong, Hui; Yang, Xue; Zhou, Mei; Li, Gang; Lin, Ling

2014-04-01

27

Time-reversal Characteristics of Quantum Normal Diffusion  

Microsoft Academic Search

This paper concerns with the time-reversal characteristics of intrinsic normal diffusion in quantum systems. Time-reversible properties are quantified by the time-reversal test; the system evolved in the forward direction for a certain period is time-reversed for the same period after applying a small perturbation at the reversal time, and the separation between the time-reversed perturbed and unperturbed states is measured

Hiroaki S. Yamada; Kensuke S. Ikeda

2011-01-01

28

A real time approach for revising generation unit performance characteristics  

SciTech Connect

This paper presents a unique method for representing the performance characteristics of generation units of electric utilities. The approach utilizes digitally sampled information in an on-line enviroment. The resulting accuracy is superior to conventional approaches, as the true time varying nature of performance characteristics is taken into account.

Viviani, G.L.; Lin, C.E.; Webb, M.G.

1985-02-01

29

Space-Time Clutter Simulation and Characteristics Analysis for SBR  

Microsoft Academic Search

In order to develop clutter mitigation techniques, clutter simulation and characteristics analysis is very important. By introducing the clutter model of space based radar (SBR) and discussing the earth's rotation effect to Doppler frequency, we get the space-time clutter spectrum of SBR. For illustration clutter characteristics, we plot clutter space-time spectrum and clutter angle-Doppler traces for two pulse repetition frequency.

Chunlin Tang; Xuegang Wang; Zhuming Chen; Fuming Sun

2009-01-01

30

Time-reversal Characteristics of Quantum Normal Diffusion  

Microsoft Academic Search

This paper concerns with the time-reversal characteristics of intrinsic\\u000anormal diffusion in quantum systems. Time-reversible properties are quantified\\u000aby the time-reversal test; the system evolved in the forward for a certain\\u000aperiod is time-reversed for the same period after applying a small\\u000aperturbation, and the separation between the time-reversed perturbed and\\u000aunperturbed states is measured as the function of perturbation

Hiroaki S. Yamada; Kensuke S. Ikeda

2011-01-01

31

Characteristic times of biased random walks on complex networks.  

PubMed

We consider degree-biased random walkers whose probability to move from a node to one of its neighbors of degree k is proportional to k(?), where ? is a tuning parameter. We study both numerically and analytically three types of characteristic times, namely (i) the time the walker needs to come back to the starting node, (ii) the time it takes to visit a given node for the first time, and (iii) the time it takes to visit all the nodes of the network. We consider a large data set of real-world networks and we show that the value of ? which minimizes the three characteristic times differs from the value ?(min)=-1 analytically found for uncorrelated networks in the mean-field approximation. In addition to this, we found that assortative networks have preferentially a value of ?(min) in the range [-1,-0.5], while disassortative networks have ?(min) in the range [-0.5,0]. We derive an analytical relation between the degree correlation exponent ? and the optimal bias value ?(min), which works well for real-world assortative networks. When only local information is available, degree-biased random walks can guarantee smaller characteristic times than the classical unbiased random walks by means of an appropriate tuning of the motion bias. PMID:24580277

Bonaventura, Moreno; Nicosia, Vincenzo; Latora, Vito

2014-01-01

32

Potentially hazardous comet warning times, characteristics, trends and countermeasures  

NASA Astrophysics Data System (ADS)

This research seeks to determine orbital trends and characteristics of comets discovered over recorded history; specifically "warning times" associated with comets that come within 1.3 astronomical unit (AU) of the Earth, called Near-Earth Objects (NEOs), and Potentially Hazardous Objects (PHOs) which come within 0.05 AU of Earth's Minimum Orbit Intersection Distance (MOID) . In this work, "warning time" means the time from discovery to perigee/closest approach to Earth, including negative warning times when the comet is discovered after close approach. This study proposes that warning times for comets approaching Earth should be increasing with increased telescope technology and an increased number of surveys focused on NEOs in the past decades. Quantification occurs by investigating all known comets through recorded history, restricting this group to relevant Near-Earth Comets (NECs), and predicting appearance and warning times of future comets using discovered trends. Data for this study was obtained from the Jet Propulsion Laboratory's (JPL) online HORIZONS system. The system has highly accurate ephemerides for asteroids and comets (612829 and 3,196 respectively on April 12, 2013) as well as other Solar System objects as well as orbital parameters and visualization tool for those objects. HORIZONS was used to build a database of all discovered comets up until February 8, 2013. The database includes: date discovered, date and close approach distance, inclination, eccentricity, total and nuclear magnitude, and several other observations used in the orbital fit. The data was then analyzed for characteristics using both MATLAB and Excel for analysis and numerical computations.

Phelps, Lyrica L.

33

Linear response characteristics of time-dependent time fractional Fokker–Planck equation systems  

NASA Astrophysics Data System (ADS)

The time fractional Fokker–Planck equation approach is an important tool for modeling subdiffusion. When the external field is time modulated, two types of time-dependent time fractional Fokker–Planck equations have been proposed, both reduced to the same time-dependent time fractional Fokker–Planck equation when the external field is time uncorrelated. The first type is strictly deduced as the continuous limit of the continuous time random walk with time modulated Boltzmann jumping weight, while the second type is derived by ideally assuming that the jump probabilities can be evaluated at the start of the waiting time prior to jumping. For the first time we obtain the linear response characteristic for the first type of the time fractional Fokker–Planck equation systems, and for a comparison we revisit the corresponding result for the second type of the time fractional Fokker–Planck equation systems, and the similarity and difference between them is discussed with an application example. The investigation not only helps in understanding the competition between subdiffusion and time-dependent modulation, but also has significance in accessing the spectral properties of spontaneous fluctuation and the linear dynamic susceptibility of external perturbation in subdiffusive processes.

Kang, Yan-Mei; Jiang, Yao-Lin; Yong, Xie

2014-11-01

34

Space-Time Characteristics of Rainfall Diurnal Variations  

NASA Technical Reports Server (NTRS)

The space-time features of rainfall diurnal variation of precipitation are systematically investigated by using the Tropical Rainfall Measuring Mission (TRMM) precipitation products retrieved from TRMM microwave imager (TMI), precipitation radar (PR) and TMI/PR combined algorithms. Results demonstrate that diurnal variability of precipitation is obvious over tropical regions. The dominant feature of rainfall diurnal cycle over, ocean is that there is consistent rainfall peak in early morning, while there is a consistent rainfall peak in mid-late afternoon over land. The seasonal variation on intensity of rainfall diurnal cycle is clearly evidenced. Horizontal distributions of rainfall diurnal variations indicate that there is a clearly early-morning peak with a secondary peak in the middle-late afternoon in ocean rainfall at latitudes dominated by large-scale convergence and deep convection. There is also an analogous early-morning peak in land rainfall along with a stronger afternoon peak forced by surface heating. Amplitude analysis shows that the patterns and its evolution of rainfall diurnal cycle are very close to rainfall distribution pattern and its evolution. These results indicate that rainfall diurnal variations are strongly associated with large-scale convective systems and climate weather systems. Phase studies clearly present the regional and seasonal features of rainfall diurnal activities. Further studies on convective and stratiform rainfall show different characteristics of diurnal cycles. Their spatial and temporal variations of convective and stratiform rainfall indicate that mechanisms for rainfall diurnal variations vary with time and space.

Yang, Song; Kummerow, Chris; Olson, Bill; Smith, Eric A.; Einaudi, Franco (Technical Monitor)

2001-01-01

35

Meteor trail characteristics observed by high time resolution lidar  

NASA Astrophysics Data System (ADS)

We report and analyse the characteristics of 1382 meteor trails based on a sodium data set of ~ 680 h. The observations were made at Yanqing (115.97° E, 40.47° N), China by a ground-based Na fluorescence lidar. The temporal resolution of the raw profiles is 1.5 s and the altitude resolution is 96 m. We discover some characteristics of meteor trails different from those presented in previous reports. The occurrence heights of the trails follow a double-peak distribution with the peaks at ~ 83.5 km and at ~ 95.5 km, away from the peak height of the regular Na layer. 4.7% of the trails occur below 80 km, and 3.25% above 100 km. 75% of the trails are observed in only one 1.5 s profile, suggesting that the dwell time in the laser beam is not greater than 1.5 s. The peak density of the trails as a function of height is similar to that of the background sodium layer. The raw occurrence height distribution is corrected taking account of three factors which affect the relative lifetime of a trail as a function of height: the meteoroid velocity (which controls the ratio of Na/Na+ ablated); diffusional spreading of the trail; and chemical removal of Na. As a result, the bi-modal distribution is more pronounced. Modelling results show that the higher peak corresponds to a meteoroid population with speeds between 20 and 30 km s-1, whereas the lower peak should arise from much slower particles in a near-prograde orbit. It is inferred that most meteoroids in this data set have masses of ~ 1 mg, in order for ablation to produce sufficient Na atoms to be detected by lidar. Finally, the evolution of longer-duration meteor trails is investigated. Signals at each altitude channel consist of density enhancement bursts with the growth process usually faster than the decay process, and there exists a progressive phase shift among these altitude channels.

Liu, Y. J.; Plane, J. M. C.; Clemesha, B. R.; Wang, J. H.; Cheng, X. W.

2014-10-01

36

Maternal Mental Health, Neighborhood Characteristics, and Time Investments in Children  

ERIC Educational Resources Information Center

We use data from the Fragile Families and Child Wellbeing Study (N = 3,572) to examine relationships between maternal depression and mothers' time investments with their 5-year-old children in outings, trips to playgrounds or parks, time spent reading with the child, and time spent playing indoors with the child. We also examine whether mothers'…

Frech, Adrianne; Kimbro, Rachel Tolbert

2011-01-01

37

On correlations and fractal characteristics of time series  

E-print Network

Correlation analysis is convenient and frequently used tool for investigation of time series from complex systems. Recently new methods such as the multifractal detrended fluctuation analysis (MFDFA) and the wavelet transform modulus maximum method (WTMM) have been developed. By means of these methods (i) we can investigate long-range correlations in time series and (ii) we can calculate fractal spectra of these time series. But opposite to the classical tool for correlation analysis - the autocorrelation function, the newly developed tools are not applicable to all kinds of time series. The unappropriate application of MFDFA or WTMM leads to wrong results and conclusions. In this article we discuss the opportunities and risks connected to the application of the MFDFA method to time series from a random number generator and to experimentally measured time series (i) for accelerations of an agricultural tractor and (ii) for the heartbeat activity of {\\sl Drosophila melanogaster}. Our main goal is to emphasize ...

Vitanov, N K; Yankulova, E D; Vitanov, Nikolay K.; Sakai, kenschi; Yankulova, Elka D.

2005-01-01

38

Nonlinear transient growth and detecting the laminar-turbulent boundary  

Microsoft Academic Search

The area of transition to turbulence has experienced a spurt of activity recently in wall-bounded shear flows where transition is triggered by finite amplitude disturbances. This has been stimulated by the discovery of new solutions to the governing equations which are disconnected from the steady unidirectional ``base'' flow in, for example, pipe flow and plane Couette flow. Understanding how all

Rich Kerswell; Chris Pringle

2009-01-01

39

Comparison of various laminar/turbulent transition models  

NASA Astrophysics Data System (ADS)

The transition model with the algebraic equation for the intermittency coefficient proposed for the bypass transition was modified for modelling of the transition at low free-stream turbulence. Further, the three-equation k-kL-? model and the Xfoil program were used for the comparison. All models were tested by means of the incompressible flow around the flat plate and symmetrical airfoils at moderate and very low free-stream turbulence.

P?íhoda, Jaromír; Straka, Petr; Fürst, Ji?í; Popelka, Lukáš

2014-08-01

40

Laminar/turbulent oscillating flow in circular pipes  

NASA Technical Reports Server (NTRS)

A two-dimensional oscillating flow analysis was conducted simulating the gas flow inside Stirling engine heat exchangers. Both laminar and turbulent oscillating pipe flow were investigated numerically for Re(max) = 1920 (Va = 80), 10,800 (Va = 272), 19,300 (Va = 272), and 60,800 (Va = 126). The results are compared with experimental results of previous investigators. Predictions of the flow regime are also checked by comparing velocity amplitudes and phase difference with those from laminar theory and quasi-steady profile. A high Reynolds number k-epsilon turbulence model was used for turbulent oscillating pipe flow. Finally, the performance of the k-epsilon model was evaluated to explore the applicability of quasi-steady turbulent models to unsteady oscillating flow analysis.

Ahn, Kyung H.; Ibrahim, Mounir B.

1992-01-01

41

Numerical Aerodynamic Optimization Incorporating Laminar-Turbulent Transition Prediction  

E-print Network

of the high-lift airfoils designed by Liebeck (Liebeck, R. H., "A Class of Airfoils Designed for High Lift and turbulent rooftops followed by Stratford-type pressure recovery to design several high-lift airfoils. Zingg [9] designed an airfoil for a high lift-to-drag ratio by combining a rooftop with a pressure gradient

Zingg, David W.

42

Laminar\\/Turbulent Plasma Jets Generated at Reduced Pressure  

Microsoft Academic Search

Laminar DC plasma jets are attractive for precisely controlled plasma-material processing. The design of a novel nontransferred plasma torch enabled the switching between turbulent and laminar plasma flows by simply changing the plasma generation parameters. Images of the plasma flows generated at different conditions are presented.

Heji Huang; Wenxia Pan; Zhiying Guo; Chengkang Wu

2008-01-01

43

Laminar-turbulent transition in pipeflow of Casson model fluids  

SciTech Connect

Methanol-coal slurries are known to behave as homogeneous non-Newtonian suspensions. Darby has shown that the Casson and Bingham models reasonably describe the rheology of methanol-lignite slurries. Theoretical methods are available for predicting critical velocities for Bingham model slurries, but none exist for Casson model slurries. Theoretical equations and design curves are derived and presented for Casson model slurries. These are based upon a proven general theory for transition critical velocities. These results are the essential first phase of a coordinated theory-based design method for transitional and turbulent flow of methanol-coal slurries and any other slurries having Casson-model rheology. 24 refs.

Hanks, R.W.

1981-12-01

44

On correlations and fractal characteristics of time series  

Microsoft Academic Search

Correlation analysis is convenient and frequently used tool for investigation of time series from complex systems. Recently new methods such as the multifractal detrended fluctuation analysis (MFDFA) and the wavelet transform modulus maximum method (WTMM) have been developed. By means of these methods (i) we can investigate long-range correlations in time series and (ii) we can calculate fractal spectra of

Nikolay K. Vitanov; kenschi Sakai; Elka D. Yankulova

2005-01-01

45

On correlations and fractal characteristics of time series  

Microsoft Academic Search

Correlation analysis is convenient and frequently used tool for investigation\\u000aof time series from complex systems. Recently new methods such as the\\u000amultifractal detrended fluctuation analysis (MFDFA) and the wavelet transform\\u000amodulus maximum method (WTMM) have been developed. By means of these methods\\u000a(i) we can investigate long-range correlations in time series and (ii) we can\\u000acalculate fractal spectra of

Nikolay K. Vitanov; kenschi Sakai; Elka D. Yankulova

2005-01-01

46

CIRCADIAN BIOLOGICAL CHARACTERISTICS AFTER SHIFTING SLEEP AND MEAL TIMES  

Microsoft Academic Search

In order to examine differences among individuals and among variables related to the rate of shift of the circadian system, nine male students were studied for 72 h under controlled physical environmental conditions. During this 3-day test, they were subjected to a 12-hour shift in the times of sleep and meals. Differences in the rate of shift from day 1

47

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

48

CIRCADIAN BIOLOGICAL CHARACTERISTICS AFTER SHIFTING SLEEP AND MEAL TIMES  

Microsoft Academic Search

Abstract In order to examine differences among,individuals and among,variables related to the rate of shift of the circadian system, nine male students were studied for 72 h under controlled physical environmental conditions. During this 3-day test, they were subjected to a 12-hour shift in the times of sleep,and meals. Differences in the,rate of shift from day 1 to day 3

K Uezono; T Kawasaki; H Sasaki; A Urae; R Urae; S Irie; M Tokunaga; G Cornélissen; J Siegelová; B Fier; F Halberg

49

Bilinear System Characteristics from Nonlinear Time Series Analysis  

SciTech Connect

Detection of changes in the resonant frequencies and mode shapes of a system is a fundamental problem in dynamics. This paper describes a time series method of detecting and quantifying changes in these parameters for a ten degree-of-freedom bilinear system excited by narrow band random noise. The method partitions the state space and computes mode frequencies and mode shapes for each region. Different regions of the space may exhibit different mode shapes, allowing diagnosis of stiffness changes at structural discontinuities. The method is useful for detecting changes in the properties of joints in mechanical systems or for detection of damage as the properties of a structure change during use.

Hunter, N.F. Jr.

1999-02-08

50

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

51

Spawning by California Golden Trout: Characteristics of Spawning Fish, Seasonal and Daily Timing, Redd Characteristics, and Microhabitat Preferences  

Microsoft Academic Search

We investigated the spawning biology of California golden trout Oncorhynchus mykiss aguabonita, an endemic subspecies of rainbow trout, in the Golden Trout Wilderness, California. We investigated the influence of stream temperature on the seasonal and daily timing of spawning, measured characteristics of completed redds, and quantified microhabitat use and preferences by spawning females. We also quantified size at sexual maturity,

Roland A. Knapp; Vance T. Vredenburg

1996-01-01

52

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

53

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

Microsoft Academic Search

Travel time has been shown to influence some aspects of cancer characteristics at diagnosis and care for women with breast\\u000a cancer, but important gaps remain in our understanding of its impact. We examined the influence of travel time to the nearest\\u000a radiology facility on breast cancer characteristics, treatment, and surveillance for women with early-stage invasive breast\\u000a cancer. We included 1,012

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

2011-01-01

54

Characteristic Variations of Sea Surface Temperature with Multiple Time Scales in the North Pacific  

Microsoft Academic Search

Temporal evolution and spectral structure of sea surface temperature (SST) anomalies in the North Pacific over the last 37 years are investigated on the three characteristic time scales: shorter than 24 months (HF), 24-60 months (ES), and longer than 60 months (DC). The leading empirical-orthogonal function (EOF) for the DC time scale is characterized by a zonally elongated monopole centered

Youichi Tanimoto; Kimio Hanawa; Yoshiaki Toba; Naoto Iwasaka

1993-01-01

55

Characteristics of the melatonin signal that provide the photoperiodic code for timing seasonal  

E-print Network

Characteristics of the melatonin signal that provide the photoperiodic code for timing seasonal the photoperiodic code for daylength in regulating seasonal breeding in the Suffolk ewe. The first series utilize daylength to time their seasonal reproductive cycle. Introduction. The importance of the pineal

Boyer, Edmond

56

Membrane bioreactor operation at short solids retention times: performance and biomass characteristics  

Microsoft Academic Search

This study investigated the performance and biomass characteristics of a membrane bioreactor (MBR) and a completely mixed activated sludge (CMAS) system operated at short solids retention times (SRT) ranging from 0.25 to 5d and hydraulic retention times of 3 and 6h. The lab-scale reactors were fed with synthetic wastewater to ensure consistency in feed composition. Results show the MBR was

How Y. Ng; Slawomir W. Hermanowicz

2005-01-01

57

Time characteristics of data storage in liquid crystals exhibiting the memory effect  

Microsoft Academic Search

An investigation was made of the time characteristics of the optical memory effect in five mixtures of nematic and cholesteric liquid crystals. The nematic component was a mixture of MBBA and EBBA, taken in equal amounts. The cholesteric component was one of the following compounds: cholesteryl decanoate; cholesteryl pelargonate; cholesteryl erucyl carbonate; cholesteryl oleyl carbonate; cholesteryl oleate. We determined the

A S Vasilevskaya; E L Kitaeva; I A Slepkov; Anatolii S Sonin

1977-01-01

58

Characteristics of the transmission of autoregressive sub-patterns in financial time series  

NASA Astrophysics Data System (ADS)

There are many types of autoregressive patterns in financial time series, and they form a transmission process. Here, we define autoregressive patterns quantitatively through an econometrical regression model. We present a computational algorithm that sets the autoregressive patterns as nodes and transmissions between patterns as edges, and then converts the transmission process of autoregressive patterns in a time series into a network. We utilised daily Shanghai (securities) composite index time series to study the transmission characteristics of autoregressive patterns. We found statistically significant evidence that the financial market is not random and that there are similar characteristics between parts and whole time series. A few types of autoregressive sub-patterns and transmission patterns drive the oscillations of the financial market. A clustering effect on fluctuations appears in the transmission process, and certain non-major autoregressive sub-patterns have high media capabilities in the financial time series. Different stock indexes exhibit similar characteristics in the transmission of fluctuation information. This work not only proposes a distinctive perspective for analysing financial time series but also provides important information for investors.

Gao, Xiangyun; An, Haizhong; Fang, Wei; Huang, Xuan; Li, Huajiao; Zhong, Weiqiong

2014-09-01

59

Learning characteristics of a space-time neural network as a tether skiprope observer  

NASA Technical Reports Server (NTRS)

The Software Technology Laboratory at the Johnson Space Center is testing a Space Time Neural Network (STNN) for observing tether oscillations present during retrieval of a tethered satellite. Proper identification of tether oscillations, known as 'skiprope' motion, is vital to safe retrieval of the tethered satellite. Our studies indicate that STNN has certain learning characteristics that must be understood properly to utilize this type of neural network for the tethered satellite problem. We present our findings on the learning characteristics including a learning rate versus momentum performance table.

Lea, Robert N.; Villarreal, James A.; Jani, Yashvant; Copeland, Charles

1993-01-01

60

Learning characteristics of a space-time neural network as a tether skiprope observer  

NASA Technical Reports Server (NTRS)

The Software Technology Laboratory at JSC is testing a Space Time Neural Network (STNN) for observing tether oscillations present during retrieval of a tethered satellite. Proper identification of tether oscillations, known as 'skiprope' motion, is vital to safe retrieval of the tethered satellite. Our studies indicate that STNN has certain learning characteristics that must be understood properly to utilize this type of neural network for the tethered satellite problem. We present our findings on the learning characteristics including a learning rate versus momentum performance table.

Lea, Robert N.; Villarreal, James A.; Jani, Yashvant; Copeland, Charles

1992-01-01

61

Time-Varying Multifractal Characteristics and Formation Mechanism of Loaded Coal Electromagnetic Radiation  

NASA Astrophysics Data System (ADS)

Dynamic collapses of deeply mined coal rocks are severe threats to miners. To predict the collapses more accurately using electromagnetic radiation (EMR), we investigate the time-varying multifractal characteristics and formation mechanism of EMR induced by underground coal mining. A series of uniaxial compression and multi-stage loading experiments with coal samples of different mechanical properties were carried out. The EMR signals during their damage evolution were monitored in real-time; the inherent law of EMR time series was analyzed by fractal theory. The results show that the time-varying multifractal characteristics of EMR are determined by damage evolutions process, the dissipated energy caused by damage evolutions such as crack propagation, fractal sliding and shearing can be regard as the fingerprint of various EMR micro-mechanics. Based on the Irreversible thermodynamics and damage mechanics, we introduced the damage internal variable, constructed the dissipative potential function and established the coupled model of the EMR and the dissipative energy, which revealed the nature of dynamic nonlinear characteristics of EMR. Dynamic multifractal spectrum is the objective response of EMR signals, thus it can be used to evaluate the coal deformation and fracture process.

Hu, Shaobin; Wang, Enyuan; Li, Zhonghui; Shen, Rongxi; Liu, Jie

2014-09-01

62

In situ real-time measurement of physical characteristics of airborne bacterial particles  

NASA Astrophysics Data System (ADS)

Bioaerosols, including aerosolized bacteria, viruses, and fungi, are associated with public health and environmental problems. One promising control method to reduce the harmful effects of bioaerosols is thermal inactivation via a continuous-flow high-temperature short-time (HTST) system. However, variations in bioaerosol physical characteristics - for example, the particle size and shape - during the continuous-flow inactivation process can change the transport properties in the air, which can affect particle deposition in the human respiratory system or the filtration efficiency of ventilation systems. Real-time particle monitoring techniques are a desirable alternative to the time-consuming process of microscopic analysis that is conventionally used in sampling and particle characterization. Here, we report in situ real-time optical scattering measurements of the physical characteristics of airborne bacteria particles following an HTST process in a continuous-flow system. Our results demonstrate that the aerodynamic diameter of bacterial aerosols decreases when exposed to a high-temperature environment, and that the shape of the bacterial cells is significantly altered. These variations in physical characteristics using optical scattering measurements were found to be in agreement with the results of scanning electron microscopy analysis.

Jung, Jae Hee; Lee, Jung Eun

2013-12-01

63

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

64

The effects of corridor characteristics on motorists' decisions to divert in resonse to time saving messages  

E-print Network

as to style and coment by: Conrad L. Dudek (Chair of Committee) R. Dale Huching n (Member) R mond Krammes (Member) J. T. P. (Head of Department) MAY 1993 ln ABSTRACT The Effects of Corridor Characteristics on Motorists' Decisions to Divert... in Response to Time Saving Messages. (May 1993) Charles John Robbins, B. S. CZ. , Manhattan College Chair of Advisory Committee: Dr. Conrad L. Dudek This thesis research is part of a study conducted by the Texas Transportation Institute (TTI) at Texas A...

Robbins, Charles John

2012-06-07

65

[Amplitude-time and phase characteristics of pulse signal force transducer in multizone pulse diagnosis].  

PubMed

The paper provides numerical calculations of module-argument relationship of the transducing function of a pulse signal force transducer in the multiarea pulse diagnostic device to the parameters of the oscillation system. It is shown that free oscillations of the low-frequency oscillation system at 300 pi rad/c or more may yield allowable phase and amplitude-time distortions of signal A transduction, with real values of damping of a low-frequency part of the oscillation system, the noninformity of amplitude-time characteristics is no more than 30% in the working frequency range of the force transducer. PMID:9611747

Boronoev, V V; Poplaukhin, V N; Storchun, Iu E

1998-01-01

66

Jitter characteristics of an on-chip voltage reference-locked time-to-digital converter  

Microsoft Academic Search

The noise and jitter characteristics of an on-chip voltage reference-locked ring oscillator used in the time-to-digital converter\\u000a (TDC) of the integrated receiver of a pulsed time-of-flight laser rangefinder are presented. The frequency of the ring oscillator,\\u000a 683 MHz, was locked to the on-chip voltage reference by means of a frequency-to-voltage converter, resulting in better than\\u000a 90 ppm\\/°C stability. The noise and jitter

Ilkka Nissinen; Juha Kostamovaara

2010-01-01

67

Time-dependent radiation characteristics of Nannochloropsis oculata during batch culture  

NASA Astrophysics Data System (ADS)

This paper reports the temporal evolution of the scattering and absorbing cross-sections of marine eustigmatophycease Nannochloropsis oculata grown in a flat-plate photobioreactor (PBR). The PBR was operated in batch mode under constant irradiance of 7500 or 10,000 lux provided by red LEDs emitting at 630 nm. The radiation characteristics between 400 and 750 nm and pigment concentrations of N. oculata were measured systematically every 24 h for up to 18 days. They were found to vary significantly with time in response to changes in light and nutrients availability. The results were interpreted in terms of up- and down-regulations of pigments and other intracellular components. Finally, this study demonstrates that the light transfer in the PBR could be predicted using constant radiation characteristics measured during the exponential growth phase with reasonable accuracy provided that the cultures were not nitrogen limited. During nitrogen starvation, pigment concentrations decreased and radiation characteristics evolved rapidly. These results will be useful in the design and operation of PBRs for biofuel production at both small and large scales.

Heng, Ri-Liang; Pilon, Laurent

2014-09-01

68

Associations of Neighborhood Characteristics with Sleep Timing and Quality: The Multi-Ethnic Study of Atherosclerosis  

PubMed Central

Study Objectives: To investigate the associations of specific neighborhood features (disorder, safety, social cohesion, physical environment, and socioeconomic status) with sleep duration and quality. Design: Cross-sectional. One wave of a population-based study (Multi-Ethnic Study of Atherosclerosis). Setting: Community-dwelling participants in New York, NY and Los Angeles, CA. Participants: There were 1,406 participants (636 males, 770 females). Interventions: NA. Measurements and Results: Sleep was assessed using reported hours of sleep, the Epworth Sleepiness Scale, and insomnia symptoms. Neighborhood characteristics were assessed via questionnaires administered to neighbors of study participants and were aggregated to the neighborhood (census tract) level using empirical Bayes estimation. An adverse social environment (characterized by high disorder, and low safety and social cohesion) was associated with shorter sleep duration after adjustment for the physical environment, neighborhood and individual-level socioeconomic status (SES), and other short sleep risk factors (mean difference per standard deviation increase in summary social environment scale 0.24 h 95% confidence interval 0.08, 0.43). Adverse neighborhood social and physical environments, and neighborhood SES were associated with greater sleepiness, but associations with physical environments were no longer statistically significant after adjustment for sociodemographic characteristics. Neighborhood SES was a weaker and less consistent predictor of specific measures of neighborhood social and physical environments. Neighborhood characteristics were not associated with insomnia. Conclusions: Shortened sleep related to adverse social environments represents one potential pathway through which neighborhoods may influence health. Citation: DeSantis AS; Diez Roux AV; Moore K; Baron KG; Mujahid MS; Nieto FJ. Associations of neighborhood characteristics with sleep timing and quality: the multi-ethnic study of atherosclerosis. SLEEP 2013;36(10):1543-1551. PMID:24082314

DeSantis, Amy S.; Diez Roux, Ana V.; Moore, Kari; Baron, Kelly G.; Mujahid, Mahasin S.; Nieto, F. Javier

2013-01-01

69

Lapse time and frequency-dependent attenuation characteristics of Kumaun Himalaya  

NASA Astrophysics Data System (ADS)

We have analyzed local earthquake data set consists of 84 well located events, recorded by a digital seismic network in the Kumaun Himalaya region during 2004-2007 to study seismic attenuation characteristics of the region. Single back-scattering assumption is used to estimate coda Q (Qc) values of the region at frequency range of 1.5, 3, 6, 8, 12 and 18 Hz for different lapse time window length. The values of Qc show a ubiquitous observation of frequency dependence and follow a substantially similar trend as observed in other tectonically active parts of the Himalaya. The lapse time dependencies of coda waves are investigated which reveal that by increasing lapse time window from 20 to 50 s, Q0 (Qc at 1 Hz) increases from 64 ± 2 to 230 ± 19 while frequency dependent parameter n decreases from 1.08 to 0.81. Increase in Qc with lapse time indicates decrease in heterogeneity with depth. The observed values of Q0 and n infer that the medium beneath the study area is highly heterogeneous and tectonically very active. The variation of Qc with lapse time at 1.5 Hz follow a similar pattern with the theoretically predicted values of Gusev (1995) although the frequency parameter n does not match with the model. It may suggest that the turbidity decays rapidly with depth for the Kumaun Himalaya. Our results are comparable with those obtained from tectonically active regions in the world.

Singh, Chandrani; Srinivasa Bharathi, V. K.; Chadha, R. K.

2012-08-01

70

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

71

Early-time plasma expansion characteristics of ionized clouds in the ionosphere  

NASA Technical Reports Server (NTRS)

A series of Vlasov-Poisson simulations were conducted with barium and lithium gas mixtures expanding into an O(+) background plasma, with the values for the Ba(+)/Li(+) composition ratios and the cloud/background density ratios based on anticipated release values in the upcoming Combined Release and Radiation Effects Satellite (CRRES) experiment. The results obtained on the early-time expansion of high-density Ba(+), Li(+), and Ba(+)-Li(+) plasma clouds into low-density O(+) background plasma complement the H(+)-O(+) expansions of Gurevich et al. (1973) and Singh and Schunk (1982, 1983), and the characteristic features observed apply to the very-early-time expansion phase of the CRRES releases.

Schunk, R. W.; Szuszczewicz, E. P.

1988-01-01

72

Lean burn limit and time to light characteristics of laser ignition in gas turbines  

NASA Astrophysics Data System (ADS)

This work details a study of laser ignition in a low pressure combustion test rig, representative of an industrial gas turbine (SGT-400, Siemens Industrial Turbomachinery Ltd.) and for the first time investigates the effect of air mass flow rate on combustion characteristics at air/fuel ratios at the lean burn limit. Both the lean burn limit and time taken to light are essential in determining the suitability of a specified air/fuel ratio, especially in multi-chamber ignition applications. Through extension of the lean burn limit and reduction of the time taken to light, the operating window for ignition with regards to the air/fuel ratio can be increased, leading to greater reliability and repeatability of ignition. Ignition of a natural gas and air mixture at atmospheric pressure was conducted using both a standard high energy igniter and a laser ignition system utilizing a Q-switched Nd:YAG laser source operating at 1064 nm wavelength. A detailed comparison of the lean burn limit and time taken to light for standard ignition and laser ignition is presented.

Griffiths, J.; Riley, M.; Kirk, A.; Borman, A.; Lawrence, J.; Dowding, C.

2014-04-01

73

Observed spatiotemporal characteristics of drought on various time scales over the Czech Republic  

NASA Astrophysics Data System (ADS)

This paper analyses the observed spatiotemporal characteristics of drought in the Czech Republic during the growing season (April to September) as quantified using the Standardised Precipitation Evapotranspiration Index (SPEI) on various time scales. The SPEI was calculated for various lags (1, 3, 6, 12, and 24 months) from monthly records of mean temperature and precipitation totals using a dense network of 184 climatological stations for the period 1961-2010. The characteristics of drought were analysed in terms of the temporal evolution of the SPEI, the frequency distribution and duration of drought at the country level, and for three regions delimited by station altitude. The driest and the wettest years during the growing season were identified. The frequency distribution of the SPEI values for seven drought category classes (in per cent) indicates that normal moisture conditions represent approximately 65 % of the total SPEI values for all time scales in all three regions, whereas moderate drought and moderate wet conditions are almost equally distributed around 10.5 %. Differences in extremely dry conditions (5 %) compared with extremely wet conditions (1.5 %) were observed with increasing SPEI time scales. The results of the non-parametric Mann-Kendall trend test applied to the SPEI series indicate prevailing negative trends (drought) at the majority of the stations. The percentage of stations displaying a significant negative trend for the 90, 95, 99, and 99.9 % confidence levels is approximately 40 %. An Empirical Orthogonal Functions (EOF) analysis was used to identify the principal patterns of variability of the SPEI during the growing season that accounted for the highest amount of statistical variance. The variance explained by the leading EOF range 66 to 56 %, whereas for EOF2 and EOF3, the value is between 7 and 11 % and between 4 and 7 %, respectively, for the SPEI is calculated for 1- to 24-month lags.

Potop, Vera; Boronean?, Constan?a; Možný, Martin; Št?pánek, Petr; Skalák, Petr

2014-02-01

74

A variable-order time-dependent neutron transport method for nuclear reactor kinetics using analytically-integrated space-time characteristics  

SciTech Connect

A new time-dependent neutron transport method based on the method of characteristics (MOC) has been developed. Whereas most spatial kinetics methods treat time dependence through temporal discretization, this new method treats time dependence by defining the characteristics to span space and time. In this implementation regions are defined in space-time where the thickness of the region in time fulfills an analogous role to the time step in discretized methods. The time dependence of the local source is approximated using a truncated Taylor series expansion with high order derivatives approximated using backward differences, permitting the solution of the resulting space-time characteristic equation. To avoid a drastic increase in computational expense and memory requirements due to solving many discrete characteristics in the space-time planes, the temporal variation of the boundary source is similarly approximated. This allows the characteristics in the space-time plane to be represented analytically rather than discretely, resulting in an algorithm comparable in implementation and expense to one that arises from conventional time integration techniques. Furthermore, by defining the boundary flux time derivative in terms of the preceding local source time derivative and boundary flux time derivative, the need to store angularly-dependent data is avoided without approximating the angular dependence of the angular flux time derivative. The accuracy of this method is assessed through implementation in the neutron transport code DeCART. The method is employed with variable-order local source representation to model a TWIGL transient. The results demonstrate that this method is accurate and more efficient than the discretized method. (authors)

Hoffman, A. J.; Lee, J. C. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI, 48109-2104 (United States)

2013-07-01

75

Scaling the characteristic time of the bursting process in the turbulent boundary layer  

NASA Astrophysics Data System (ADS)

Characteristic time scales associated with bursting events in the turbulent boundary layer were examined over a very large range of Reynolds numbers based on momentum thickness of 1010, 2870, 4850, and 5×106. Well-resolved hot-wire measurements were obtained at the lowest three Reynolds numbers in a low-speed wind tunnel with a long development length and compared to hot-wire and sonic anemometer measurements in the near-neutral atmospheric surface layer over the salt flats of Utah’s western desert. Bursting events were detected using the modified U-level threshold-crossing algorithm outlined by Luchik and Tiederman (1987) [1]. The same procedure and codes were used to analyze all time series records from both the wind tunnel and field experiments. The time between events, Te, and the event duration, ?T, were calculated and normalized using four different types of scalings: inner, outer, mixed, and Taylor microscales. It was found that both Reynolds number and wall-normal trends in the mode of Te were eliminated when scaled by the Taylor microscale. Furthermore, constant (Reynolds number independent) values of the nondimensional meanTe and ?T were found in a narrow wall-normal region near the top of the buffer layer when the data were normalized by the Taylor microscale.

Metzger, Meredith; McKeon, Beverley; Arce-Larreta, Enrique

2010-07-01

76

[Sensing characteristics of a real-time monitor using a photoionization detector on organic solvent vapors].  

PubMed

Measurements of organic solvents in the work environment are carried out by either direct sampling using plastic bags/gas chromatography, solid sorbent adsorption using charcoal tubes/gas chromatography, or by a direct reading method using detector tubes. However, these methods cannot always measure the work environment accurately because the concentration of hazardous materials changes from time to time, and from space to space. In this study, the sensor characteristics of a real time monitor using a photoionization detector that can monitor vapor concentration continuously were investigated for 52 organic solvent vapors that are required to be measured in the work environment by the Ordinance of Organic Solvent Poisoning Prevention in Japan. The sensitivity of the monitor was high for the solvents with low ionization potential. However, the sensitivity for the solvents with high ionization potential was low, and the sensor could not detected 7 solvents. Calibration of the sensor using a standard gas was desirable before being used for measurement because the sensitivity of the sensor was variable. PMID:23270260

Hori, Hajime; Ishematsu, Sumiyo; Fueta, Yukiko; Hinoue, Mitsuo; Ishidao, Toru

2012-12-01

77

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

78

Measurements of admittances and characteristic combustion times of reactive gaseous propellant coaxial injectors  

NASA Technical Reports Server (NTRS)

The results of an experimental investigation that was concerned with the quantitative determination of the capabilities of combustion processes associated with coaxial injectors to amplify and sustain combustor oscillations was described. The driving provided by the combustion process was determined by employing the modified standing-wave method utilizing coaxial injectors and air-acetylene mixtures. Analyses of the measured data indicate that the investigated injectors are capable of initiating and amplifying combustion instabilities under favorable conditions of injector-combustion coupling and over certain frequency ranges. These frequency ranges and the frequency at which an injector's driving capacity is maximum are observed to depend upon the equivalence ratio, the pressure drop across the injector orifices and the number of injector elements. The characteristic combustion times of coaxial injectors were determined from steady state temperature measurements.

Janardan, B. A.; Daniel, B. R.; Zinn, B. T.

1979-01-01

79

Characteristics and performance of aerobic granular sludge treating rubber wastewater at different hydraulic retention time.  

PubMed

The influence of hydraulic retention time (HRT, 24, 12, and 6h) on the physical characteristics of granules and performance of a sequencing batch reactor (SBR) treating rubber wastewater was investigated. Results showed larger granular sludge formation at HRT of 6h with a mean size of 2.0±0.1mm, sludge volume index of 20.1mLg(-1), settling velocity of 61mh(-1), density of 78.2gL(-1) and integrity coefficient of 9.54. Scanning electron microscope analyses revealed different morphology of microorganisms and structural features of granules when operated at various HRT. The results also demonstrated that up to 98.4% COD reduction was achieved when the reactor was operated at low HRT (6h). Around 92.7% and 89.5% removal efficiency was noted for ammonia and total nitrogen in the granular SBR system during the treatment of rubber wastewater. PMID:24704837

Rosman, Noor Hasyimah; Nor Anuar, Aznah; Chelliapan, Shreeshivadasan; Md Din, Mohd Fadhil; Ujang, Zaini

2014-06-01

80

Summer-time thermal environment characteristics in central Korea using Landsat TM data  

NASA Astrophysics Data System (ADS)

Urban heat island(UHI) effect is the temperature increase in urban areas compared to that in surrounding rural areas and is caused by a number of factors, such as land use / land cover (LULC)change, increase fuel consumption and lack of vegetation in urban core areas. The replacement of natural surface types from soil and vegetation to impervious materials such as asphalt and concrete structures affects the albedo and runoff characteristics of the urban land surface. The impervious materials have a lower albedo than soil and vegetation and hold more solar energy, which increase land surface temperature (LST) during the summer season. UHI effects on the center region of South Korea were analyzed using remotely sensed data. The objectives of this study are to examine the summer-time thermal environment of the Cheongju city in Korea, review the satellite assessment of the thermal environment of LULC, and compare thermal environment in 1991 to 2006. Chang detection of thermal environment is performed to determine whether a significant change has occurred. The average of LST of study area has increased 2.7°C during 15years because of changed land cover from paddy field and forest to barren, factory, and concrete. This case study indicates that barren, factory, and residential apartment over on the Cheongju and Ochang increased in the late 1990s and that vegetation area are changing predominantly in the direction of decreased forest and paddy fields. Decreasing forest and paddy fields are an important result, as it suggests that directional changes are occurring on the Cheongju and Ochang that are consistent with experimental urban warming. The most influential factors for controlling the summer-time thermal environment are the distribution of surface cover characteristics (e.g. LULC) and urban morphology, such as urban consistence materials, geometry, development stage, and density.

Park, Jin-Ki; Park, Jong-Hwa; Na, Sang-il

2010-10-01

81

Maternal characteristics and timing of presentation following pre-labour rupture of membranes  

PubMed Central

Background: To examine the influence of maternal characteristics on timing of presentation for intervention following pre-labour rupture of membrane (PROM) at term. Materials and Methods: This was a descriptive study of cases of term PROM with singleton births at the University of Benin Teaching Hospital (UBTH) from October 2011 to December 2012. Interval from onset of PROM to presentation to hospital was used as dependent variable. From the study population, two groups were identified based on time interval (?24 hours or >24 hours) from PROM to presentation to hospital and their relationship to socio-demographic characteristic examined. Results: Over the study period, records of 110 women met the inclusion criteria and were selected for analysis. Their mean age was 29.26 ± 0.67 years; they were all married with 41.8% being nulliparous women. The mean gestational age at presentation with PROM was 38.5 ± 1.2. Over 50% had tertiary level of education. Overall, 38.2% were in social class 1. With regard to maternal response behaviour to PROM, 65.5% presented to the hospital within 24 hours while 34.5% presented after 24 hours of rupture of membranes. Majority of those that presented within 24 hours of PROM were in (upper) social class 1 and 2 and this differed significantly from those that presented after 24 hours, most of whom were in (lower) social class 3,4 and 5; [56 (77.8%) vs 16 (22.2%) and 14 (36.8%) vs 24 (63.2%)] P = 0.0001. Conclusion: Delay in presentation after PROM, illustrative of maternal under utilisation of BPACR package, is associated with being in a lower social class. Socio-economic and educational empowerment of women is advocated, while prospective research on maternal perception and attitude towards ANC is proposed. PMID:24970972

Osaikhuwuomwan, James A.; Osemwenkha, Abieyuwa P.

2014-01-01

82

Influence of age and aerobic fitness on the multifractal characteristics of electrocardiographic RR time-series  

PubMed Central

Multifractal properties of electrocardiographic inter-beat (RR) time-series offer insight into its long-term correlation structure, independently of RR variability. Here we quantify multifractal characteristics of RR data during 24-h diurnal-nocturnal activity in healthy participants. We tested the hypotheses that (1) age, gender and aerobic fitness influence RR multifractal properties, and that (2) these are influenced by circadian variation. Seventy adults (39 males) aged 19–58 years and of various fitness levels were monitored using 24-h ECG. Participants were dichotomized by median age and fitness for sub-group analysis. Gender and fitness were independent of age (p = 0.1, p > 0.5). Younger/older group ages were substantially different (p < 0.0005) and were independent of gender and fitness. Multifractality was quantified using the probability spectrum of Hölder exponents (h), from which modal h (h*) and the full-width and half-widths at half-maximum measures (FWHM, HWHM+, and HWHM?) were derived. FWHM decreased (p = 0.004) and h* increased (p = 0.011) in older people, indicating diminished long-range RR correlations and weaker anti-persistent behavior. Anti-persistent correlation (h*) was strongest in the youngest/fittest individuals and weakest in the oldest/least fit individuals (p = 0.015). Long-range correlation (HWHM+/FWHM) was strongest in the fittest males and weakest in the least fit females (p = 0.007–0.033). Multifractal RR characteristics in our healthy participants showed strong age-dependence, with diminished long-range anti-persistent correlation in older people. Circadian variation of these characteristics was influenced by fitness and gender: fitter males and females of all ages had the greatest degree of multifractality or long-range order. Multifractal characterization appears to be a useful method for exploring the physiological basis of long-term correlation structure in RR time-series as well as the benefits thereon of physical fitness training. PMID:23717283

Lewis, Michael J.; McNarry, Melitta A.

2013-01-01

83

COMPARISON OF CHARACTERISTIC TIME DIAGNOSTICS FOR IGNITION AND OXIDATION OF FUEL\\/OXIDIZER MIXTURES BEHIND REFLECTED SHOCK WAVES  

Microsoft Academic Search

Various methods for determining characteristic times of shock-tube ignition and oxidation are compared. Onset and peak times were obtained from time histories for four different species (CH, CH*, OH, OH*) as predicted by a modern detailed kinetics mechanism. Appropriate submechanisms for CH* and OH* formation and quenching were added to the existing mechanism to differentiate the excited-state species from the

J. M. HALL; M. J. A. RICKARD; E. L. PETERSEN

2005-01-01

84

Effect of nitrogen source, rate and time of application on soil nitrogen status and on the characteristics of the plant  

E-print Network

EFFECT OF NITROGEN SOURCE, RATE AND TIME OF APPLICATION ON SOIL NITROGEN STATUS AND ON THE CHARACTERISTICS OF THE PLANT By Mohamed K. Sadik A Thesis Submitted to the Graduate School of the Agricultural and Mechanical College of Texxas... in partial, fulfillment of the requirements for the degree of MASTER OF SCIENCE Major Subject: Soil and Plant Sciences May, 1962 EFFECT F NITROGEN SOURCE, RATE AND TIME OF APPLICATION ON SOIL NITROGEN STATUS AND ON THE CHARACTERISTICS OF THE PI ANT' A...

Sadik, Mohamed Kamal

2012-06-07

85

Second order modified method of characteristics mixed defect-correction finite element method for time dependent Navier–Stokes problems  

Microsoft Academic Search

In this paper, a second order modified method of characteristics defect-correction (SOMMOCDC) mixed finite element method\\u000a for the time dependent Navier–Stokes problems is presented. In this method, the hyperbolic part (the temporal and advection\\u000a term) are treated by a second order characteristics tracking scheme, and the non-linear term is linearized at the same time.\\u000a Then, we solve the equations with

Zhiyong Si

86

Effect of solids retention time and wastewater characteristics on biological phosphorus removal.  

PubMed

The paper deals with the effect of wastewater, plant design and operation in relation to biological nitrogen and phosphorus removal and the possibilities to model the processes. Two Bio-P pilot plants were operated for 2.5 years in parallel receiving identical wastewater. The plants had SRT of 4 and 21 days, the latter had nitrification and denitrification. The plant with 4 days SRT had much more variable biomass characteristics, than the one with the high SRT. The internal storage compounds, PHA, were affected significantly by the concentration of fatty acids or other easily degradable organics in the wastewater, and less by the plant lay-out. The phosphorus removal is mainly dependent on availability in the wastewater of fatty acids but also by the suspended solids in the effluent, which is higher in the plant with nitrification-denitrification, probably due to a higher SVI or denitrification in the settler. The addition of glucose to the influent seems to have an effect on the performance of the plants similar to that of acetic acid. In spite of great load variations over time to the pilot plants and the different operational modes, the study of population dynamics showed less significant variations with time which has importance in relation to modelling. The overall conclusion of the comparison between the two plants is that the biological phosphorus removal efficiency under practical operating conditions is affected by the SRT in the plant and the wastewater composition. Thus great care should be taken when extrapolating results from one type of plant to another. Indirectly the experiments confirm that results from lab-experiments with artificial wastewater are difficult to extrapolate through modelling to real life wastewater and conditions. The 2.5 years time series can be valuable in verification of models for Nitrogen and Enhanced Biological Phosphorus Removal. PMID:11989867

Henze, M; Aspegren, H; Jansen, J la Cour; Nielsen, P H; Lee, N

2002-01-01

87

Long-Characteristics Methods with Piecewise Linear Sources in Space and Time for Transport on Unstructured Grids  

E-print Network

characteristic (STLC) method with various source approximations including several that employ a piece-wise linear (PWL) approximation spatially. In the prism-PWL (PPWL) method the coefficient of each PWL spatial function is linear in time in each space-time cell...

Pandya, Tara M 1984-

2012-10-23

88

Identification of Land-Cover Characteristics Using MODIS Time Series Data: An Application in the Yangtze River Estuary  

PubMed Central

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

2013-01-01

89

Temporal direct numerical simulation of transitional natural-convection boundary layer under conditions of considerable external turbulence effects  

NASA Astrophysics Data System (ADS)

Results of direct numerical simulations for time-developing air natural-convection boundary layer are presented. Computations have been performed assuming periodicity conditions in both the directions parallel to the vertical isothermal hot plate. The contribution is mainly focused on understanding of laminar-turbulent transition peculiarities in the case of perturbation action of external turbulence that is modeled by isotropic disturbances initially introduced into the computational domain. Special attention is paid to identification and analysis of evolving three-dimensional vortices that clearly manifest themselves through the whole stages of laminar-turbulent transition in the boundary layer. A comparison of computed profiles of mean velocity, mean temperature and fluctuation characteristics for turbulent regimes of convection with experimental data is performed as well.

Abramov, Alexey G.; Smirnov, Evgueni M.; Goryachev, Valery D.

2014-08-01

90

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

91

Magnitude and relative distribution of kettlebell snatch force-time characteristics.  

PubMed

Lake, JP, Hetzler, BS, Lauder, MA. Magnitude and relative distribution of kettlebell snatch force-time characteristics. J Strength Cond Res 28(11): 3063-3072, 2014-The aim of this study was to compare mechanical output from kettlebell snatch and 2-handed kettlebell swing exercise. Twenty-two men performed 3 sets of 8 kettlebell snatch and 2-handed swing exercise with a 24-kg kettlebell on a force platform. Vertical and horizontal net impulse, mean force, displacement, the magnitude, and rate of work performed displacing the kettlebell-and-lifter center of mass (CM), phase durations and impulse ratio (horizontal to resultant) were calculated from force data. The results of repeated-measures analysis of variance showed that: (a) vertical CM displacement was significantly larger during kettlebell snatch exercise (22 ± 4 vs. 18 ± 5 cm, p = 0.001), and vertical CM displacement was significantly larger than horizontal CM displacement, regardless of exercise (20 ± 3 vs. 7 ± 1 cm, p < 0.0001); (b) the magnitude (253 ± 73 vs. 3 ± 1 J, p < 0.0001) and rate of work (714 ± 288 vs. 11 ± 4 W, p < 0.0001) performed to vertically displace the CM was larger than the horizontal equivalent in both exercises, and the magnitude (5 ± 2 vs. 1 ± 1 J, p < 0.0001) and rate of work (18 ± 7 vs. 4 ± 3 W, p < 0.0001) performed to horizontally displace the CM during 2-handed swing exercise was significantly larger than the kettlebell snatch equivalent; (c) this was underpinned by the magnitude of horizontal impulse (29 ± 7 vs. 18 ± 7 N·s, p < 0.0001) and the impulse ratio (23 vs. 14%, p < 0.0001). These findings reveal that, apart from the greater emphasis, 2-handed swing exercise places on horizontal mechanical output, the mechanical output of the 2 exercises is similar. Research shows that 2-handed swing exercise improves maximum and explosive strength. These results suggest that strength and conditioning coaches should consider using kettlebell snatch and 2-handed swing exercise interchangeably for the ballistic component of athlete strength and conditioning programs. PMID:24845206

Lake, Jason P; Hetzler, Brandon S; Lauder, Mike A

2014-11-01

92

Study of the time-frequency characteristics of continuous gravity data sequence  

NASA Astrophysics Data System (ADS)

The continuous gravity measurements contained much valuable signal which was maybe caused by internal and external change of the Earth, which offered abundant information to study activities of the Earth. In the past decades, researchers mostly focused on discussing the relationship between the gravity variation and geodynamical processes. Here we studied the temporal variation of the gravity field through the continuous gravity records. Our goal was to detect certain geophysical signal on the order of a few tens of micro-Gal from the gravity data sequence. The gravity data sequences were recorded by the Scintrex g-Phone relative gravimeters those were located at the numerous observation stations of mainland China which had well-controlled observation systems. We presented a two-step procedure to study the signal of gravity variation. Firstly, we developed a Linear Similarity filtering technique which could reduce the drift of gravity instrument effectively by using two relative gravimeters at the same station by the reason of the short-term liner drift feature of gravimeters. Based on the method above, we gained non-tidal gravity variation more accurate that contained much geophysical signal which was associated with geodynamical phenomena. Secondly, we employed the time-frequency analysis techniques to analyze the feature of different temporal variation signal and tried to find some periodic and non-periodic characteristics of the continuous gravity data sequence. Moreover, we compared the results to the mobile repeated gravity measurements on ground and acquired the spatial and temporal gravity variation at last. We also expected to find some anomaly signal related to the activities of tectogenesis and fault movement prior to the destructive earthquakes from the continuous gravity data sequence. Acknowledgment: We acknowledge the financial support of the Basic Scientific Research Foundation of Institute of Geophysics CEA (DQJB12B20, DQJB12C03 and DQJB12B14), the Scientific and Technological Support Foundation of CEA (2012BAK19B01-05-02) and the National Natural Science Foundation of China (41104046).

Weimin, X.; Shi, C.; Lei, S.; Hongyan, L.

2013-12-01

93

Quality characteristics of a dry-cured lamb leg as affected by tumbling after dry-salting and processing time.  

PubMed

The aim of this study was to evaluate selected quality characteristics of a dry-cured lamb leg with different tumbling treatments after salting. The characteristics were measured at different processing times. Three batches of dry-cured lamb legs (nine legs per batch) were prepared with no-, short- and long-tumbling treatments, and microbial counts, NaCl, aw, proximate composition, pH, free fatty acids, water soluble nitrogen, volatile compounds, texture and colour were evaluated at days 1, 22 and 71 of processing. Furthermore, a descriptive sensory analysis (flavour and texture) was performed in the final product (day 71). Time-related changes were observed for most of the characteristics studied. The effect of tumbling was only observed for the sensory attribute pastiness that was higher in tumbled legs. Methyl-branched butanal was only detected in tumbled legs. PMID:24553493

Villalobos-Delgado, Luz H; Caro, Irma; Blanco, Carolina; Morán, Lara; Prieto, Nuria; Bodas, Raul; Giráldez, Francisco J; Mateo, Javier

2014-05-01

94

Empirical calibration of time series monitoring methods using receiver operating characteristic curves  

Microsoft Academic Search

Time series monitoring methods, such as the Brown and Trigg methods, have the purpose of detecting pattern breaks (or “signals”) in time series data reliably and in a timely fashion. Traditionally, researchers have used the average run length (ARL) statistic on results from generated signal occurrences in simulated time series data to calibrate and evaluate these methods, with a focus

Jacqueline Cohen; Samuel Garman; Wilpen Gorr

2009-01-01

95

Spatio-temporal evolution and time-stable characteristics of soil moisture within remote sensing footprints with varying soil,  

E-print Network

Spatio-temporal evolution and time-stable characteristics of soil moisture within remote sensing measure soil moisture at the footprint scale, a scale of several hundred square meters or kilometers of within-footprint variability of soil moisture are needed to determine the factors governing hydrologic

Mohanty, Binayak P.

96

An Investigation of the Relationship Between Selected Student Entering Characteristics and Time Required to Achieve Unit Mastery.  

ERIC Educational Resources Information Center

The relationship betwee n a composite of student entry characteristics--unit pretest score, number of skills to be mastered in the unit, the student's intelligence quotient and age, units previously mastered--and the amount of time required to complete one of four units of D or E level mathematics was investigated. Beta weights for the regression…

Yeager, John L.; Kissel, Mary Ann

97

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

SciTech Connect

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. [P. N. Lebedev Physical Institute, Leninskii Prospect 53, Moscow 119991 (Russian Federation)

2013-07-15

98

Detection and Estimation of the Volume of Pneumothorax Using Real-Time Sonography: Efficacy Determined by Receiver Operating Characteristic Analysis  

Microsoft Academic Search

OBJECTIVE. The purpose of this study was to determine the efficacy of real-time sonography for the detection and estimation of the volume of pneumothorax using receiver operating characteristic (ROC) analysis in 27 patients evaluated by five radi- ologists using previously described sonographic findings. MATERIALS AND METHODS. Bilateral chest sonograms were obtained in 27 patients after we performed 26 needle biopsies

Craig T. Reiheld; Spencer B. Gay

99

Professional Characteristics and Job Satisfaction Among SGIM Members: A Comparison of Part-time and Full-time Physician Members  

Microsoft Academic Search

BACKGROUND  As more physicians work part-time (PT), the faculty, institutions, and organizations that represent them should understand\\u000a the factors that motivate and satisfy these physicians.\\u000a \\u000a \\u000a \\u000a OBJECTIVE  Compare factors associated with job satisfaction among PT and full-time (FT) academic physicians.\\u000a \\u000a \\u000a \\u000a DESIGN  Cross-sectional survey.\\u000a \\u000a \\u000a \\u000a PARTICIPANTS  Members of the Society of General Internal Medicine (SGIM), a national, academic Internal Medicine organization.\\u000a \\u000a \\u000a \\u000a RESULTS  Fifty percent (1,396 of 2,772) of

Rachel B. Levine; Rebecca A. Harrison; Hilit F. Mechaber; Christopher Phillips; Thomas H. Gallagher

2008-01-01

100

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

101

Professional Characteristics and Job Satisfaction Among SGIM Members: A Comparison of Part-time and Full-time Physician Members  

PubMed Central

BACKGROUND As more physicians work part-time (PT), the faculty, institutions, and organizations that represent them should understand the factors that motivate and satisfy these physicians. OBJECTIVE Compare factors associated with job satisfaction among PT and full-time (FT) academic physicians. DESIGN Cross-sectional survey. PARTICIPANTS Members of the Society of General Internal Medicine (SGIM), a national, academic Internal Medicine organization. RESULTS Fifty percent (1,396 of 2,772) of SGIM members responded, 11% work PT. Compared to FT, PT physicians were more often female (85% vs 38%, p?

Harrison, Rebecca A.; Mechaber, Hilit F.; Phillips, Christopher; Gallagher, Thomas H.

2008-01-01

102

Spectrogram analysis of the time–frequency characteristics of ocean wind waves  

Microsoft Academic Search

The spectrogram based on the short-time Fourier transform is proposed as a tool to study the time frequency evolution of the properties of ocean wind waves. After defining the method to determine the spectrogram of wind waves an example of application is given by analyzing the time series from three sea states concerning a swell, a wind sea and a

C. Guedes Soares; Z. Cherneva

2005-01-01

103

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

104

Clinical Characteristics of Neonatal Meningomyelocele Cases and Effect of Operation Time on Mortality and Morbidity  

Microsoft Academic Search

Objective: We aimed to evaluate the clinical features, short-term prognosis, and effect of operation time on mortality and morbidity in neonates with meningomyelocele. Methods: This prospective study was conducted between January 2006 and December 2008. Clinical features, defective area, existence of additional anomalies, operation time, and morbidity and mortality data were recorded. The effectof operation time on mortality and morbidity

Ali Bulbul; Emrah Can; Lida Gunes Bulbul; Serdar Cömert; Asiye Nuhoglu

2010-01-01

105

Are middle schools harmful? The role of transition timing, classroom quality and school characteristics.  

PubMed

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 sample (NICHD Study of Early Child Care and Youth Development, n = 855; 52% Female, 82% White). Classroom quality (observed and teacher-reported) and school characteristics (composition and size) were considered as explanations for any relationships between school-level and student functioning. Fifth grade middle school students did not differ from those in elementary school, but students entering middle school in 6th grade, compared to those in elementary school, experienced lower classroom quality, which in turn predicted slightly lower achievement. They also had lower school engagement, explained by larger school size. Classroom quality and school characteristics predicted youth functioning regardless of school type. We suggest reshaping the research and policy debate with renewed focus on classroom quality and school size instead of grade organization. PMID:22143392

Holas, Igor; Huston, Aletha C

2012-03-01

106

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

107

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

108

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

109

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

110

Characteristics of young children's utilization of a robot during play time : A case study  

Microsoft Academic Search

This is a case study of the behavior that was observed when young children were given free access to Intelligent Service Robot iRobiQ during their free play time at kindergarten. The investigator conducted a 30-min observation of one class of three-year-olds and one of four-year-olds during their free play time both in the morning and in the afternoon, twice a

Eunja Hyun; Hyunmin Yoon

2009-01-01

111

Reversal of the laminar-turbulent transition of a boundary layer on a cooled surface  

Microsoft Academic Search

A new series of experiments has investigated the influence of hoarfrost on the surface of a model on the position of the boundary layer transition for the same water vapor concentration in the working part of the wind tunnel and the same Mach number and unit Reynolds number but different amounts (masses) of hoarfrost on the investigated section of the

V. I. Lysenko; A. A. Maslov

1984-01-01

112

Laminar-turbulent boundary-layer transition over a rough rotating disk F. Zoueshtiagha)  

E-print Network

of irregular roughness at high shearing stresses are calculated and show excellent agreement by permanently attaching appropriately sized quartz granules to the surface of a circular smooth glass disk. Each disk can be mounted on the rotating support structure. The granules were sieved using a sieve shaker

Thomas, Peter J.

113

Laminar-turbulent transition calculations of heat transfer at hypersonic Mach numbers over sharp cones  

NASA Technical Reports Server (NTRS)

Computations of the hypersonic flow around sharp cones were carried out using the PNS code with attention given to the heat transfer predictions around the transition region. Results of calculations performed over 5, 8, and 10 deg half-angle sharp cones in the Mach number range of 7 to 10 are presented. It is noted that calculations of this type have become an integral part of the general design procedure for hypersonic vehicles such as the National Aerospace Plane and the Space Shuttle.

Kaul, U. K.

1988-01-01

114

Prediction of transitional (laminar-turbulent) hypersonic flows using the parabolized Navier-Stokes equations  

NASA Technical Reports Server (NTRS)

Hypersonic transitional flow predictions have been made using the parabolized Navier-Stokes equations with an algebraic transition/turbulence model by appropriately modulating the turbulent viscosity with the available intermittency functions for incompressible and compressible flows. A comparison between the predictions with and without a low Reynolds number correction has also been made. The predictions are compared with the available experimental data and with the theory over a range of Mach number. A simple Re(theta)/M(delta) criterion is shown to satisfactorily predict the meridional variation of the onset location of transition on a cone at a small angle of attack, whereas none of the correlations discussed can do that. Various available correlations are discussed vis-a-vis the predictions as to the locations of the onset and the end of transition.

Kaul, Upender K.

1989-01-01

115

Numerical investigation of laminar-turbulent transition in a flat plate wake  

Microsoft Academic Search

Lamina-turbulent transition of high-deficit flat plate wakes is investigated by direct numerical simulations using the complete Navier Stokes equations. The simulations are based on a spatial model so that both the base flow and the disturbance flow can develop in the downstream direction. The Navier Stokes equations are used in a vorticity-velocity form and are solved using a combination of

Hermann F. Fasel; Alan C. Newell; David I. Dratler

1990-01-01

116

Numerical investigation of laminar-turbulent transition in a flat plate wake  

NASA Technical Reports Server (NTRS)

Lamina-turbulent transition of high-deficit flat plate wakes is investigated by direct numerical simulations using the complete Navier Stokes equations. The simulations are based on a spatial model so that both the base flow and the disturbance flow can develop in the downstream direction. The Navier Stokes equations are used in a vorticity-velocity form and are solved using a combination of finite difference and spectral approximations. Fourier series are used in the spanwise direction. Second-order finite-differences are used to approximate the spatial derivatives in the streamwise and transverse directions. For the temporal discretion, a combination of ADI, Crank-Nicolson, and Adams-Bashforth methods is employed. The discretized velocity equations are solved using fast Helmholtz solvers. Code validation is accomplished by comparison of the numerical results to both linear stability and to experiments. Calculations of two- and/or three-dimensional sinuous and mode disturbances in the wake of flat plate are undertaken. For calculations of two-dimensional disturbances, the wake is forced at an amplitude level so that nonlinear disturbance development may be observed. In addition, the forcing amplitude is varied in order to determine its effect on the disturbance behavior. To investigate the onset of three-dimensionality, the wake is forced with a small-amplitude three-dimensional disturbance and a larger amplitude two-dimensional disturbance. The two-dimensional forcing amplitude is varied in order to determine its influence on the three-dimensional flow field.

Fasel, Hermann F.; Newell, Alan C.; Dratler, David I.

1990-01-01

117

Multiple laminar-turbulent transition cycles around a swept leading edge  

NASA Astrophysics Data System (ADS)

Certain interesting flow features involving multiple transition/relaminarization cycles on the leading edge of a swept wing at low speeds are reported here. The wing geometry tested had a circular nose and a leading edge sweep of 60°. Tests were made at a chord Reynolds number of 1.3 × 106 with model incidence ? varied in the range of 3°-18° in discrete steps. Measurements made included wing chord-wise surface pressure distributions and wall shear stress fluctuations (using hot-film gages) within about 10 % of the chord in the leading edge zone. Results at ? = 16° and 18° showed that several (often incomplete) transition cycles between laminar-like and turbulent-like flows occurred. These rather surprising results are attributable chiefly to the fact that the Launder acceleration parameter K (appropriately modified for swept wings) can exceed a critical range more than once along the contour of the airfoil in the leading edge region. Each such crossing results in a relaminarization followed by direct retransition to turbulence as K drops to sufficiently low values. It is further shown that the extent of each observed transition zone (of either type) is consistent with earlier data acquired in more detailed studies of direct transition and relaminarization. Swept leading edge boundary layers therefore pose strong challenges to numerical modelling.

Mukund, R.; Narasimha, R.; Viswanath, P. R.; Crouch, J. D.

2012-12-01

118

The role of laminar-turbulent transition in gas turbine engines: A discussion  

SciTech Connect

An extended discussion of Mayle's critical study of transition phenomena in gas turbine engines is presented. Attention is focused on transition in decelerating flow regions, which are the major sources of loss production for axial turbomachine blades. The following points are examined in detail: (a) the physics of transition and its implications for the correlation of various transition phenomena; (b) the relative importance of pressure gradient and free-stream turbulence in controlling transition; (c) the influence of pressure gradient on periodic-unsteady transition; (d) the correlation of transition length under conditions of arbitrary pressure gradient and free-stream turbulence level; and (e) transition behavior in laminar separation bubbles. The discussion examines various differences in philosophy concerning the above phenomena and makes further suggestions for transition research, which may assist in resolving the issues raised.

Walker, G.J. (Univ. of Tasmania, Hobart (Australia))

1993-04-01

119

Experimental study of the laminar-turbulent transition of a concave wall in a parallel flow  

NASA Technical Reports Server (NTRS)

The instability of the laminar boundary layer flow along a concave wall was studied. Observations of these three-dimensional boundary layer phenomena were made using the hydrogen-bubble visualization technique. With the application of stereo-photogrammetric methods in the air-water system it was possible to investigate the flow processes qualitatively and quantitatively. In the case of a concave wall of sufficient curvature, a primary instability occurs first in the form of Goertler vortices with wave lengths depending upon the boundary layer thickness and the wall curvature. At the onset the amplification rate is in agreement with the linear theory. Later, during the non-linear amplification stage, periodic spanwise vorticity concentrations develop in the low velocity region between the longitudinal vortices. Then a meandering motion of the longitudinal vortex streets subsequently ensues, leading to turbulence.

Bippes, H.

1978-01-01

120

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

121

Characteristic recovery times of Forbush-type decreases in the cosmic radiation. I - Observations at earth at different energies  

NASA Technical Reports Server (NTRS)

Data on 30 asymmetric Forbush decreases recorded by the IMP spacecraft at 1 AU and the Mt. Washington neutron monitor over the period 1972-84 are examined to characterize the recovery characteristics of cosmic rays after the events. The spacecraft data are concentrated at energies of 1.7 GV, while the terrestrial instruments recorded events at 5 GV. Attention is paid to the relative amplitudes of the recorded transient decreases, the characteristic recovery times, and the energy dependence of the amplitudes and recovery time. The recovery times were found to be equal at both energy levels, supporting a concept of energy independence for the recoveries. Also, no correlations were found between the recovery times and the occurrences of a solar magnetic field reversal or with phase in the solar modulation cycle. A time-dependent, two-dimensional model is defined, which expresses the cosmic ray particle distributions as a function of the decay of the disturbance, with a small dependence on the transport parameters of the cosmic rays.

Lockwood, J. A.; Webber, W. R.; Jokipii, J. R.

1986-01-01

122

Effect of different egg storage times on some egg quality characteristics and hatchability of pheasants (Phasianus colchicus).  

PubMed

In this study, some quality characteristics and hatchability characteristics of 1 to 2, 3 to 4, 5 to 6, 7 to 8, 9 to 10, 11 to 12, and 13 to 14 d stored pheasant eggs were investigated. Although it was determined that the effect of storage time on egg weight, shape index, and albumen weight was not significant, the effect of storage time on eggshell weight, shell thickness, yolk weight, albumen index, yolk index, Haugh unit, shell percentage, albumen percentage, and yolk percentage was significant (P<0.05). It was determined that prolonged storage time caused a decrease in the albumen index and Haugh unit value but an increase in the yolk index of pheasant eggs. There was no positive or negative effect of storage time on the fertility rates and hatchability of fertile eggs, but there was a negative effect of storage time on hatchability on d 8 (P<0.05). Pheasant eggs should not be stored more than 8 d. PMID:19151360

Demirel, S; Kirikçi, K

2009-02-01

123

Characteristics and control response of the TOPAZ II Reactor System Real-time Dynamic Simulator  

SciTech Connect

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, K.S.

1993-11-12

124

Effect of reaction time on the characteristics of catalytically grown boron nitride nanotubes  

NASA Astrophysics Data System (ADS)

The paper reports on the growth of boron nitride nanotube (BNNTs) on Si substrate by catalytic chemical vapor deposition technique and the effect of reaction time and temperature on the size and purity were investigated. Scanning electron microscopy image revealed the bamboo-like BNNTs of multiwalled type with interlayer spacing of 0.34 nm. EDX analysis described the presence of a small percentage of Mg in the sample, indicating the combination of base-tip growth model for the sample synthesized at 1200°C. The reaction time has an effect of extending the length of the BNNTs until the catalyst is oxidized or covered by growth precursor.

Mohamed, Norani Muti; Ahmad, Pervaiz; Saheed, Mohamed Shuaib Mohamed; Burhanudin, Zainal Arif

2014-10-01

125

Beef palatability as influenced by live animal characteristics, time-on-feed and carcass traits  

E-print Network

the preparation of this manuscript. Fur- ther appreciation is extended to Dr. T. R. Dutson, Mr. C. E. Murphey, Dr. G. T. King and Dr. J. D. Tatum for their advice and contributions during the course of this study. Sincere appreciation is extended... the accuracy of such predictions. In a recent study, Tatum (1978) examined the effects of USDA feeder grade, time-on-feed, subcutaneous fat thick- ness, breed-type and USDA quality grade on beef palatability within a relatively narrow range in time...

Dolezal, Howard Glen

2012-06-07

126

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

127

Characteristics of Disfluency Clusters over Time in Preschool Children Who Stutter  

ERIC Educational Resources Information Center

Purpose: Disfluency clusters in preschool children were analyzed to determine whether they occurred at rates above chance, whether they changed over time, and whether they could differentiate children who would later persist in, or recover from, stuttering. Method: Thirty-two children recruited near stuttering onset were grouped on the basis of…

Sawyer, Jean; Yairi, Ehud

2010-01-01

128

Real time estimation of photovoltaic modules characteristics and its application to maximum power point operation  

Microsoft Academic Search

In this paper, an approximate curve fitting method for photovoltaic modules is presented. The operation is based on solving a simple solar cell electrical model by a microcontroller in real time. Only four voltage and current coordinates are needed to obtain the solar module parameters and set its operation at maximum power in any conditions of illumination and temperature. Despite

Ausias Garrigós; José M. Blanes; José A. Carrasco; Juan B. Ejea

2007-01-01

129

Comparison of gender-specific human embryo development characteristics by time-lapse technology.  

PubMed

Numerous studies indicate that there might be differences in embryo growth dynamics between male and female embryos. However, current data in humans are scarce and the results are inconclusive or conflicting. This study asks whether there exist gender-specific embryo development kinetics or parameters between human male and female embryos that can be observed by time-lapse technology. Study included data from 139 consecutive cycles (177 embryos transferred, 179 sacs analysed) with positive pregnancy that resulted in 100% implantation. Single- or double-embryo transfers were performed. Cases were analysed for parameters including cleavage time points and duration in each cleavage from two cells to hatching blastocyst stages and time interval between cleavages. Morphokinetic parameters of 78 female and 60 male embryos from a total of 119 cycles (139 sacs were examined after transfer of 138 embryos) were processed for data analysis according to the gender group. A detailed analysis of the data regarding each time point or interval between consecutive events according to these groups showed them to be similar in cell division kinetics, from the early cleavage through their development to blastocyst stage. However, female embryos showed earlier cavitation than male embryos, but the results did not reach statistical significance. PMID:24925308

Serdarogullari, Munevver; Findikli, Necati; Goktas, Cihan; Sahin, Oya; Ulug, Ulun; Yagmur, Erbil; Bahceci, Mustafa

2014-08-01

130

BLAST Training: Estimating Channel Characteristics for High Capacity Space-Time Wireless  

Microsoft Academic Search

BLAST (Bell Labs Layered Space-Time) is a multiple-antenna communicationscheme whose outage capacity in a Rayleigh flat fading environment grows linearlywith the minimum of the number of transmit and receive antennas, with no increasein bandwidth or transmitted power. Based on its knowledge of the matrix ofpropagation coefficients, the receiver performs two critical operations: nulling andcancellation, that in effect create independent virtual

Thomas L. Marzetta

1999-01-01

131

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, here…

Kitano, Katsunori; Fukai, Tomoki

2004-01-01

132

Statistical characteristics of storm interevent time, depth, and duration for eastern New Mexico, Oklahoma, and Texas  

USGS Publications Warehouse

The design of small runoff-control structures, from simple floodwater-detention basins to sophisticated best-management practices, requires the statistical characterization of rainfall as a basis for cost-effective, risk-mitigated, hydrologic engineering design. The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, has developed a framework to estimate storm statistics including storm interevent times, distributions of storm depths, and distributions of storm durations for eastern New Mexico, Oklahoma, and Texas. The analysis is based on hourly rainfall recorded by the National Weather Service. The database contains more than 155 million hourly values from 774 stations in the study area. Seven sets of maps depicting ranges of mean storm interevent time, mean storm depth, and mean storm duration, by county, as well as tables listing each of those statistics, by county, were developed. The mean storm interevent time is used in probabilistic models to assess the frequency distribution of storms. The Poisson distribution is suggested to model the distribution of storm occurrence, and the exponential distribution is suggested to model the distribution of storm interevent times. The four-parameter kappa distribution is judged as an appropriate distribution for modeling the distribution of both storm depth and storm duration. Preference for the kappa distribution is based on interpretation of L-moment diagrams. Parameter estimates for the kappa distributions are provided. Separate dimensionless frequency curves for storm depth and duration are defined for eastern New Mexico, Oklahoma, and Texas. Dimension is restored by multiplying curve ordinates by the mean storm depth or mean storm duration to produce quantile functions of storm depth and duration. Minimum interevent time and location have slight influence on the scale and shape of the dimensionless frequency curves. Ten example problems and solutions to possible applications are provided.

Asquith, William H.; Roussel, Meghan C.; Cleveland, Theodore G.; Fang, Xing; Thompson, David B.

2006-01-01

133

Vocal characteristics of pygmy blue whales and their change over time.  

PubMed

Vocal characteristics of pygmy blue whales of the eastern Indian Ocean population were analyzed using data from a hydroacoustic station deployed off Cape Leeuwin in Western Australia as part of the Comprehensive Nuclear-Test-Ban Treaty monitoring network, from two acoustic observatories of the Australian Integrated Marine Observing System, and from individual sea noise loggers deployed in the Perth Canyon. These data have been collected from 2002 to 2010, inclusively. It is shown that the themes of pygmy blue whale songs consist of ether three or two repeating tonal sounds with harmonics. The most intense sound of the tonal theme was estimated to correspond to a source level of 179 ± 2 dB re 1 ?Pa at 1 m measured for 120 calls from seven different animals. Short-duration calls of impulsive downswept sound from pygmy blue whales were weaker with the source level estimated to vary between 168 to 176 dB. A gradual decrease in the call frequency with a mean rate estimated to be 0.35 ± 0.3 Hz/year was observed over nine years in the frequency of the third harmonic of tonal sound 2 in the whale song theme, which corresponds to a negative trend of about 0.12 Hz/year in the call fundamental frequency. PMID:22225022

Gavrilov, Alexander N; McCauley, Robert D; Salgado-Kent, Chandra; Tripovich, Joy; Burton, Chris

2011-12-01

134

The Real Time Diagnostics of Combustion Characteristics of Solid Propellant by Remote Sensing FTIR System  

Microsoft Academic Search

The flame infrared emission spectra between 4700 and 800 cm of nitroguanidine solid propellant combustion were recorded using a real time, remote sensing Fourier transform infrared (FTIR) spectrometer with a spectral resolution of 2 cm. The combustion flame temperature of this high intensity IR propellant combustion was studied via the fine structure of the rotational vibrational emission bands of HF (4400?3950 cm) and

Yan Li; Junde Wang

2003-01-01

135

Space-Time Clustering Characteristics of Tuberculosis in China, 2005-2011  

PubMed Central

Objectives China is one of the 22 tuberculosis (TB) high-burden countries in the world. As TB is a major public health problem in China, spatial analysis could be applied to detect geographic distribution of TB clusters for targeted intervention on TB epidemics. Methods Spatial analysis was applied for detecting TB clusters on county-based TB notification data in the national notifiable infectious disease case reporting surveillance system from 2005 to 2011. Two indicators of TB epidemic were used including new sputum smear-positive (SS+) notification rate and total TB notification rate. Global Moran’s I by ArcGIS was used to assess whether TB clustering and its trend were significant. SaTScan software that used the retrospective space-time analysis and Possion probability model was utilized to identify geographic areas and time period of potential clusters with notification rates on county-level from 2005 to 2011. Results Two indicators of TB notification had presented significant spatial autocorrelation globally each year (p<0.01). Global Moran’s I of total TB notification rate had positive trend as time went by (t=6.87, p<0.01). The most likely clusters of two indicators had similar spatial distribution and size in the south-central regions of China from 2006 to 2008, and the secondary clusters in two regions: northeastern China and western China. Besides, the secondary clusters of total TB notification rate had two more large clustering centers in Inner Mongolia, Gansu and Qinghai provinces and several smaller clusters in Shanxi, Henan, Hebei and Jiangsu provinces. Conclusion The total TB notification cases clustered significantly in some special areas each year and the clusters trended to aggregate with time. The most-likely and secondary clusters that overlapped among two TB indicators had higher TB burden and risks of TB transmission. These were the focused geographic areas where TB control efforts should be prioritized. PMID:24367604

Zhao, Fei; Cheng, Shiming; He, Guangxue; Huang, Fei; Zhang, Hui; Xu, Biao; Murimwa, Tonderayi C.; Cheng, Jun; Hu, Dongmei; Wang, Lixia

2013-01-01

136

Exercise training can improve spatial characteristics of time-critical obstacle avoidance in elderly people.  

PubMed

Fall prevention programs have rarely been evaluated by quantitative movement analysis methods. Quantitative movement analyses could provide insight into the mechanisms underlying the effects of training. A treadmill obstacle avoidance task under time pressure has recently been used to evaluate a fall prevention exercise program for community-dwelling elderly people and it showed that participants improved their obstacle avoidance success rates. The mechanism, by which the increased success rates were achieved, however, remained to be determined. Participants were elderly who had fallen at least once in the year prior to participation. They were assigned to either the exercise or the control group. The control group did not receive any specific treatment. The exercise group was administered a five week exercise program, which consisted of exercises on a functionally oriented obstacle course, walking exercises, and practice of fall techniques. Pre- and post-intervention laboratory obstacle avoidance tests were conducted. Three possible determinants of success were investigated, namely avoidance reaction times, the distribution of avoidance strategies, and three spatial parameters (toe distance, foot clearance and heel distance). Analysis yielded significant TimexGroup interactions in heel distances. The exercise group increased heel distance, while the control group did not. Increased heel distance may result in reduced risk of heel contact with the obstacle and, consequently, larger success rates. The remaining parameters showed no effect of training. In conclusion, the training program was effective in improving time-critical obstacle avoidance skills. In every day life, these effects of training may contribute to less obstacle-related fall incidents in elderly. In addition, these findings could indicate that the execution of other time-critical events, like an actual fall, could also be improved by training. PMID:18524403

Weerdesteyn, Vivian; Nienhuis, Bart; Duysens, Jacques

2008-10-01

137

Taekwondo techniques and competition characteristics involved in time-loss injuries  

Microsoft Academic Search

The purpose of this study was to assess time-loss injuries in young and adult taekwondo athletes. Participants were 2739 children (11-13 years), Junior (14-17 years) and adult males and females (18 years and older) competing in the national Greek championships. Injury data were collected by project staff with all diagnoses made by the tournament physician. Odds ratios were computed as

Konstantinos Beis; Willy Pieter; George Abatzides

138

Influence of salt content and processing time on sensory characteristics of cooked "lacón".  

PubMed

The influence of salt content and processing time on the sensory properties of cooked "lacón" were determined. "Lacón" is a traditional dry-cured and ripened meat product made in the north-west of Spain from the fore leg of the pig, following a similar process to that of dry-cured ham. Six batches of "lacón" were salted with different amounts of salt (LS (3 days of salting), MS (4 days of salting) and HS (5 days of salting)) and ripened during two times (56 and 84 days of dry-ripening). Cured odour in all batches studied, red colour and rancid odour in MS and HS batches, flavour intensity in MS batch and fat yellowness, rancid flavour and hardness in the HS batch were significantly different with respect to the time of processing. Appearance, odour, flavour and texture were not significantly affected by the salt content (P>0.05). However, the saltiness score showed significant differences with respect to the salt levels in all studied batches (56 and 84 days of process). The principal component analysis showed that physicochemical traits were the most important ones concerning the quality of dry-cured "lacón" and offered a good separation of the mean samples according to the dry ripening days and salt level. PMID:21168978

Purriños, Laura; Bermúdez, Roberto; Temperán, Sara; Franco, Daniel; Carballo, Javier; Lorenzo, José M

2011-04-01

139

Characteristics of the near-Earth magnetotail variations at the time of substorm onset  

NASA Astrophysics Data System (ADS)

From the result of our statistical analysis with GEOTAIL and THEMIS data, we confirmed that tailward plasma flows are created in association with the plasma flows that propagate from X ~ -12 Re toward the earth at the time of substorm onset. To understand the physical mechanism of the formation of such tailward flows, we have performed a case study of substorm event occurred at 10:46 UT on June 22, 1997 when the GEOTAIL was located at (X, Y) ~ (-9, 6) Re and encountered with the flow bursts. The event started with earthward flows for about 2 min with the northward magnetic field enhancement, followed by slow tailward flows. Such an earthward and tailward flow sequence repeated three times. By calculating the electric current from electron and ion moment data, we found the variation in the X-component of JxB force that can be interpreted to have close relationship with the enhancement of earthward flows. Namely, the flows are not simply generated at a distant location and reach the GEOTAIL, but they are still under acceleration at X ~ -10 Re. After the passage of the flow front, the (JxB)x term takes negative values. The time derivative of Vx does not necessarily correspond to (JxB)x/mn. This inconsistency might be due to the contribution of the terms such as -grad P or (Vgrad) V. It is also necessary to check the possibility of the decoupling between electrons and ions as well as the effect of anomalous resistivity.

Machida, S.; Miyashita, Y.; Ieda, A.; Saito, Y.

2013-12-01

140

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

141

Physicochemical and toxicological characteristics of welding fume derived particles generated from real time welding processes.  

PubMed

Welding fume particles have been well studied in the past; however, most studies have examined welding fumes generated from machine models rather than actual exposures. Furthermore, the link between physicochemical and toxicological properties of welding fume particles has not been well understood. This study aims to investigate the physicochemical properties of particles derived during real time welding processes generated during actual welding processes and to assess the particle size specific toxicological properties. A compact cascade impactor (Harvard CCI) was stationed within the welding booth to sample particles by size. Size fractionated particles were extracted and used for both off-line physicochemical analysis and in vitro cellular toxicological characterization. Each size fraction was analyzed for ions, elemental compositions, and mass concentration. Furthermore, real time optical particle monitors (DustTrak™, TSI Inc., Shoreview, Minn.) were used in the same welding booth to collect real time PM2.5 particle number concentration data. The sampled particles were extracted from the polyurethane foam (PUF) impaction substrates using a previously developed and validated protocol, and used in a cellular assay to assess oxidative stress. By mass, welding aerosols were found to be in coarse (PM 2.5–10), and fine (PM 0.1–2.5) size ranges. Most of the water soluble (WS) metals presented higher concentrations in the coarse size range with some exceptions such as sodium, which presented elevated concentration in the PM 0.1 size range. In vitro data showed size specific dependency, with the fine and ultrafine size ranges having the highest reactive oxygen species (ROS) activity. Additionally, this study suggests a possible correlation between welders' experience, the welding procedure and equipment used and particles generated from welding fumes. Mass concentrations and total metal and water soluble metal concentrations of welding fume particles may be greatly influenced by these factors. Furthermore, the results also confirmed the hypothesis that smaller particles generate more ROS activity and should be evaluated carefully for risk assessment. PMID:24592438

Chang, Cali; Demokritou, Philip; Shafer, Martin; Christiani, David

2013-01-01

142

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

143

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

2012-07-01

144

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

2012-03-01

145

Fall detection and classifications based on time-scale radar signal characteristics  

NASA Astrophysics Data System (ADS)

Unattended catastrophic falls result in risk to the lives of elderly. There are growing efforts and rising interest in detecting falls of the aging population, especially those living alone. Radar serves as an effective non-intrusive sensor for detecting human activities. For radar to be effective, it is important to achieve low false alarms, i.e., the system can reliably differentiate between a fall and other human activities. In this paper, we discuss the time-scale based signal analysis of the radar returns from a human target. Reliable features are extracted from the scalogram and are used for fall classifications. The classification results and the advantages of using a wavelet transform are discussed.

Gadde, Ajay; Amin, Moeness G.; Zhang, Yimin D.; Ahmad, Fauzia

2014-05-01

146

Characteristics of Settling Coral Reef Fish Are Related to Recruitment Timing and Success  

PubMed Central

Many marine populations exhibit high variability in the recruitment of young into the population. While environmental cycles and oceanography explain some patterns of replenishment, the role of other growth-related processes in influencing settlement and recruitment is less clear. Examination of a 65-mo. time series of recruitment of a common coral reef fish, Stegastes partitus, to the reefs of the upper Florida Keys revealed that during peak recruitment months, settlement stage larvae arriving during dark lunar phases grew faster as larvae and were larger at settlement compared to those settling during the light lunar phases. However, the strength and direction of early trait-mediated selective mortality also varied by settlement lunar phase such that the early life history traits of 2–4 week old recruit survivors that settled across the lunar cycle converged to more similar values. Similarly, within peak settlement periods, early life history traits of settling larvae and selective mortality of recruits varied by the magnitude of the settlement event: larvae settling in larger events had longer PLDs and consequently were larger at settlement than those settling in smaller pulses. Traits also varied by recruitment habitat: recruits surviving in live coral habitat (vs rubble) or areas with higher densities of adult conspecifics were those that were larger at settlement. Reef habitats, especially those with high densities of territorial conspecifics, are more challenging habitats for young fish to occupy and small settlers (due to lower larval growth and/or shorter PLDs) to these habitats have a lower chance of survival than they do in rubble habitats. Settling reef fish are not all equal and the time and location of settlement influences the likelihood that individuals will survive to contribute to the population. PMID:25250964

Rankin, Tauna L.; Sponaugle, Su

2014-01-01

147

Characteristics of settling coral reef fish are related to recruitment timing and success.  

PubMed

Many marine populations exhibit high variability in the recruitment of young into the population. While environmental cycles and oceanography explain some patterns of replenishment, the role of other growth-related processes in influencing settlement and recruitment is less clear. Examination of a 65-mo. time series of recruitment of a common coral reef fish, Stegastes partitus, to the reefs of the upper Florida Keys revealed that during peak recruitment months, settlement stage larvae arriving during dark lunar phases grew faster as larvae and were larger at settlement compared to those settling during the light lunar phases. However, the strength and direction of early trait-mediated selective mortality also varied by settlement lunar phase such that the early life history traits of 2-4 week old recruit survivors that settled across the lunar cycle converged to more similar values. Similarly, within peak settlement periods, early life history traits of settling larvae and selective mortality of recruits varied by the magnitude of the settlement event: larvae settling in larger events had longer PLDs and consequently were larger at settlement than those settling in smaller pulses. Traits also varied by recruitment habitat: recruits surviving in live coral habitat (vs rubble) or areas with higher densities of adult conspecifics were those that were larger at settlement. Reef habitats, especially those with high densities of territorial conspecifics, are more challenging habitats for young fish to occupy and small settlers (due to lower larval growth and/or shorter PLDs) to these habitats have a lower chance of survival than they do in rubble habitats. Settling reef fish are not all equal and the time and location of settlement influences the likelihood that individuals will survive to contribute to the population. PMID:25250964

Rankin, Tauna L; Sponaugle, Su

2014-01-01

148

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. PMID:10427024

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

1999-01-01

149

Correlations between X-ray Spectral and Timing Characteristics in Cyg X-2  

E-print Network

Correlations between the quasi-periodic oscillations (QPOs) and the spectral power-law index have been reported for a number of black hole candidate sources and for four neutron star (NS) sources, 4U 0614+09, 4U 1608-52, 4U 1728-34 and Sco X-1. An examination of QPO frequencies and index relationship in Cyg X-2 is reported herein. The RXTE spectrum of Cyg X-2 can be adequately represented by a simple two-component model of Compton up-scattering with a soft photon electron temperature of about 0.7 keV and an iron K-line. Inferred spectral power-law index shows correlation with the low QPO frequencies. We find that the Thomson optical depth of the Compton cloud (CC) tau, in framework of spherical geometry, is in the range of ~4-6, which is consistent with the neutron star's surface being obscured. The NS high frequency pulsations are presumably suppressed as a result of photon scattering off CC electrons because of such high values of tau. We also point out a number of similarities in terms timing (presence of ...

Titarchuk, Lev; Shaposhnikov, Nikolai

2007-01-01

150

Correlations between X-ray Spectral and Timing Characteristics in Cyg X-2  

E-print Network

Correlations between the quasi-periodic oscillations (QPOs) and the spectral power-law index have been reported for a number of black hole candidate sources and for four neutron star (NS) sources, 4U 0614+09, 4U 1608-52, 4U 1728-34 and Sco X-1. An examination of QPO frequencies and index relationship in Cyg X-2 is reported herein. The RXTE spectrum of Cyg X-2 can be adequately represented by a simple two-component model of Compton up-scattering with a soft photon electron temperature of about 0.7 keV and an iron K-line. Inferred spectral power-law index shows correlation with the low QPO frequencies. We find that the Thomson optical depth of the Compton cloud (CC) tau, in framework of spherical geometry, is in the range of ~4-6, which is consistent with the neutron star's surface being obscured. The NS high frequency pulsations are presumably suppressed as a result of photon scattering off CC electrons because of such high values of tau. We also point out a number of similarities in terms timing (presence of low and high frequency QPOs) and spectral (high CC optical depth and low CC plasma temperature) appearances between Cyg X-2 and Sco X-1.

Lev Titarchuk; Sergey Kuznetsov; Nikolai Shaposhnikov

2007-06-12

151

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 60 days 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

2014-02-15

152

Spectral and time domain characteristics of single muscle fibre action potentials during continuous activity extracted from model considerations.  

PubMed

A model of the muscle fibre extracellular action potentials (ECAPs) calculation using experimentally recorded intracellular action potentials (ICAPs) has been applied to investigate the effect of repetitive stimulation on the electrical activity of isolated frog muscle fibres. The ECAPs were calculated both at small (0.01 mm) and at large (5 mm) radial distances to the fibre axis, and their relationship with the original ICAP parameters has been inferred. Fourier transformation of the calculated ECAPs in order to obtain the spectral characteristics and to trace out their behaviour during continuous fibre activity was performed. Stimulation frequency dependence on the ECAP time characteristics and on the shift of the maximum spectral density towards low frequencies at small and large radial distance were observed. The spectral density peak frequency is propagation velocity (PV)-dependent. The advantage of the presented method over the available experimental extracellular recording techniques from isolated muscle fibers is the possibility to show the effect of continuous muscle fibre activity on the parameters of the ECAPs and their spectral characteristics at large radial distance, which is not experimentally accessible. Our results are in agreement with those experimentally obtained. The results from the model prove the role of changes in PV of excitation along the muscle fibres (representing the last link in the complex organized motor system) in the development of fatigue. PMID:9851022

Radicheva, N; Slavcheva, G

1998-11-01

153

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

154

Carotid artery pulse wave time characteristics to quantify ventriculoarterial responses to orthostatic challenge.  

PubMed

Central blood pressure waveforms contain specific features related to cardiac and arterial function. We investigated posture-related changes in ventriculoarterial hemodynamics by means of carotid artery (CA) pulse wave analysis. ECG, brachial cuff pressure, and common CA diameter waveforms (by M-mode ultrasound) were obtained in 21 healthy volunteers (19-30 yr of age, 10 men and 11 women) in supine and sitting positions. Pulse wave analysis was based on a timing extraction algorithm that automatically detects acceleration maxima in the second derivative of the CA pulse waveform. The algorithm enabled determination of isovolumic contraction period (ICP) and ejection period (EP): ICP=43+/-8 (SD) ms (4-ms precision), and EP=302+/-16 (SD) ms (5-ms precision). Compared with the supine position, in the sitting position diastolic blood pressure (DBP) increased by 7+/-4 mmHg (P<0.001) and R-R interval decreased by 49+/-82 ms (P=0.013), reflecting normal baroreflex response, whereas EP decreased to 267+/-19 ms (P<0.001). Shortening of EP was significantly correlated to earlier arrival of the lower body peripheral reflection wave (r2=0.46, P<0.001). ICP increased by 7+/-7 ms (P<0.001), the ICP-to-EP ratio increased from 14+/-3% (supine) to 19+/-3% (P<0.001) and the DBP-to-ICP ratio decreased by 7% (P=0.023). These results suggest that orthostasis decreases left ventricular output as a result of arterial wave reflections and, presumably, reduced cardiac preload. We conclude that CA ultrasound and pulse wave analysis enable noninvasive quantification of ventriculoarterial responses to changes in posture. PMID:17317873

Reesink, Koen D; Hermeling, Evelien; Hoeberigs, M Christianne; Reneman, Robert S; Hoeks, Arnold P G

2007-06-01

155

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

NASA Astrophysics Data System (ADS)

Tracer studies, using Gran alkalinity and ?18O, in nested sub-basins of the 230 km 2 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 Hydrology Of Soil Type (HOST) digital data base—exerted the strongest influence on flow path partitioning and mean residence times. Smallest groundwater contributions (˜30-40%) and shortest residence times (˜2-5 months) were observed in catchments dominated by peat and/or shallow alpine soils and bedrock. Longer residence times (˜12-15 months) and greater groundwater contributions (˜45-55%) were observed in catchments dominated by more freely draining podzolic, sub-alpine and alluvial soils. These different subcatchment responses were integrated to give intermediate residence times (˜6 months) at the catchment outfall. The influence of catchment topography and scale appeared to be largely mediated by their influence on soil cover and distribution. The study illustrates the potential utility of integrating digital landscape analysis with tracer studies to understand the hydrological functioning of mesoscale catchments.

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

2006-06-01

156

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

157

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

PubMed Central

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 frequency nor food × frequency interactions was significant for the parameters studied. PMID:20440906

Brambillasca, Sebastian; Purtscher, Frederick; Britos, Alejandro; Repetto, Jose L.; Cajarville, Cecilia

2010-01-01

158

Effects of adding whole body vibration to squat training on isometric force/time characteristics.  

PubMed

Resistance training interventions aimed at increasing lower-body power and rates of force development have produced varying results. Recent studies have suggested that whole-body low-frequency vibration (WBLFV) may elicit an acute postactivation potentiation response, leading to acute improvements in power and force development. Potentially, the use of WBLFV between sets of resistance training rather than during training itself may lead to increased recruitment and synchronization of high-threshold motor units, minimize fatigue potential, and facilitate the chronic adaptation to resistance exercise. The purpose of this study was to determine the effects of applying TriPlaner, WBLFV, prior to and then intermittently between sets of Smith machine squats on short-term adaptations in explosive isometric force expression. Thirty recreationally resistance trained men aged 18-30 were randomly assigned to 1 of 3 groups: resistance training only (SQT, n = 11), resistance plus whole-body vibration (SQTV, n = 13), or active control (CON, n = 6). An isometric squat test was performed prior to and following a 6-week periodized Smith machine squat program. Whole-body low-frequency vibration was applied 180 seconds prior to the first work set (50 Hz, 2-4 mm, 30 seconds) and intermittently (50 Hz, 4-6 mm, 3 x 10 seconds, 60 seconds between exposures) within a 240-second interset rest period. Subjects were instructed to assume a quarter squat posture while positioning their feet directly under their center of mass, which was modified using a handheld goniometer to a knee angle of 135 +/- 5 degrees . Instructions were given to subjects to apply force as fast and as hard as possible for 3.5 seconds. Isometric force (N) and rates of force development (N.s(-1)) were recorded from the onset of contraction (F(0)) to time points corresponding to 30, 50, 80, 100, 150, and 250 milliseconds, as well as the peak isometric rate of force development (PISORFD), and rate of force development to initial peak in force (RFDinitial). Repeated measures analysis of variance and analysis of covariance revealed no significant group by trial interactions for isometric rate of force development (ISORFD) between 0-30, 0-50, 0-80, 0-100, 0-150, and 0-250 milliseconds and PISORFD (p > 0.05). A significant group x trial interaction was seen for RFDinitial with SQTV >CG (p = 0.04, mean difference 997.2 N.s(-1)) and SQTV >SQT (p = 0.04, mean difference 1,994.22 N.s(-1)). Significant trial by covariate interactions (week one measures for ISORFD) and main effects for trial were observed for ISORFD between 0-80, 0-100, 0-and 150 milliseconds; PISORFD; and RFDinitial (p < 0.01). A significant trial effect was seen for Finitial (%) when expressed as a relative percentage of maximal voluntary contraction (MVC) (MVC = 100%) (p = 0.015; week 1 > week 7, mean difference, 5.82%). No significant differences were seen for any other force variables from the onset of contraction to MVC between weeks 1 and 7 (p > 0.05). The data suggest that there was a significant benefit afforded by adding WBLFV to a short-term resistance training protocol with regard to "explosive" strength expression. The addition of vibration prior to and between sets of resistance exercise may be a viable alternative to vibration applied during resistance exercise when trying to improve "explosive" isometric strength. PMID:19924007

Lamont, Hugh S; Cramer, Joel T; Bemben, Debra A; Shehab, Randa L; Anderson, Mark A; Bemben, Michael G

2010-01-01

159

Sex differences in anthropometric characteristics, motor and cognitive functioning in preschool children at the time of school enrolment.  

PubMed

The study included a sample of 333 preschool children (162 male and 171 female) at the time of school enrolment. Study subjects were recruited from the population of children in kindergartens in the cities of Novi Sad, Sombor, Sremska Mitrovica and Backa Palanka (Province of Voivodina, Serbia). Eight anthropometric variables, seven motor variables and one cognitive variable were analyzed to identify quantitative and qualitative sex differences in anthropometric characteristics, motor and cognitive functioning. Study results showed statistically significant sex differences in anthropometric characteristics and motor abilities in favor of male children, whereas no such difference was recorded in cognitive functioning. Sex differences found in morphological and motor spaces contributed to structuring proper general factors according to space and sex. Somewhat stronger structures were observed in male children. The cognitive aspect of functioning yielded better correlation with motor functioning in female than in male children. Motor functioning correlated better with morphological growth and development in male children, whereas cognitive functioning was relatively independent. These results are not fully in accordance with the current concept of general conditions in preschool children, nor they fully confirm the theory of integral development of children, hence they should be re-examined in future studies. Although these study results cannot be applied to sports practice in general, since we believe that it is too early for preschool children to take up sports and sport competitions, they are relevant for pointing to the need of developing general motor ability and motor behavior in preschool children. PMID:20102050

Bala, Gustav; Kati?, Ratko

2009-12-01

160

Relating Low-Flow Characteristics to the Baseflow-Recession Time Scale at Partial-Record Streamflow Sites  

NASA Astrophysics Data System (ADS)

Estimates of low-flow characteristics from regional regression equations have been shown to benefit from use of basin-specific information on baseflow recession. In applications to date, the measures of baseflow recession have been estimated from continuous streamflow records. This seriously limits their usefulness as predictors of low-flow characteristics at sites without continuous streamflow records. A method is proposed herein for obtaining such information for sites with very few streamflow measurements ("partial-record sites"). Simulation of one to four pairs of low flow values at each partial-record site is done by a "random bootstrapping-Monte Carlo method" using continuous record sites. These low-flow values are used to compute up to four estimates of the baseflow-recession measure. The constants of the regression models are calculated from the data at continuous record sites, and evaluated at simulated partial-record sites. This method is tested with data from 93 continuously gaged rural basins in the southeast United States. The introduction of a baseflow-recession time constant as a predictor approximately halved the root-mean-square estimation error relative to a conventional drainage-area regression. This result is more realistic than one assuming that a continuously monitored site is available for evaluation.

Eng, K.; Milly, P. C.

2006-05-01

161

A bottom-up approach: using residence time distributions and characteristic biogeochemical timescales to upscale multiphysics models of hyporheic exchange  

NASA Astrophysics Data System (ADS)

Residence time distributions (RTDs) and characteristic biogeochemical time scales (CBTSs) are integrated metrics that can be used to describe the biogeochemical evolution of water within hydrologic systems. RTDs describe the time that water and solutes are in contact with the system and strongly depend on the forcing and geomorphic features driving exchange and the system's hydraulic properties. On the other hand, CBTSs describe the time necessary for a biogeochemical transformation to take place and depend on the reaction type, solute concentrations entering the system, and chemical kinetics (or thermodynamics). Comparing RTDs and CBTSs allow us to evaluate the potential for transformation within the hydrologic system. In this work, we illustrate this approach with sinuosity-driven hyporheic zones; however, these concepts can be applied to other hydrologic systems. A two-dimensional, transient, numerical flow and transport model is used to illustrate the effect that dynamics, caused by deterministically generated flood events, has on flow fields and RTDs, and therefore on the character of the hyporheic zone as a biogeochemical reactor. A simple analytical model is used to estimate the CBTSs associated to the degradation of dissolved organic carbon in these hydrologic systems, which are compared to numerically-modeled RTDs and used to estimate the biogeochemical zonation within the HZ and its net biogeochemical response. Additionally, we use a multispecies, reactive transport model to assess this approach, paying special attention to those portions of the system with intermittent hyporheic contributions. In particular, transient flow results in time-varying hot-spot for biogeochemical reactions and induces the emergence of new modes on the dynamic RTDs, which are observed within the system and at the outlet. This parsimonious approach can be used as a predictive tool to quantify the potential of meanders as biogeochemical reactors at the watershed scale with the aid of historic discharge data, remote sensing data, and GIS processing techniques.

Gomez, Jesus D.; Wilson, John L.

2013-04-01

162

Effects of polychlorinated biphenyls and nutritional restriction on barbituate-induced sleeping times and selected blood characteristics in raccoons ( Procyon lotor )  

Microsoft Academic Search

Hepatic microsomal enzyme activity was induced in wild-trapped raccoons (Procyon lotor) and selected blood characteristics were measured in an effort to detect responses due to PCB ingestion, nutritional restriction, and their interactions. Barbiturate-induced sleeping times were used as an index of hepatic microsomal activity because they have been used reliably by other workers. Blood characteristics examined in the study were

W. Edward Montz; William C. Card; Roy L. Kirkpatrick

1982-01-01

163

Characteristic length scales and time-averaged transport velocities of suspended sediment in the mid-Atlantic Region, USA  

USGS Publications Warehouse

Watershed Best Management Practices (BMPs) are often designed to reduce loading from particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles are only moved downstream episodically, resting for long periods in storage between transport events. A theory is developed that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage given sediment budget data (by grain size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended sediment transport length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At 5 upland watersheds of the mid-Atlantic region, transport length scales for silt-clay range from 4 to 60 km, while those for sand range from 0.4 to 113 km. Mean sediment velocities for silt-clay range from 0.0072 km/yr to 0.12 km/yr, while those for sand range from 0.0008 km/yr to 0.20 km/yr, 4–6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100–1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to determine the complete distribution of suspended sediment velocities in real watersheds.

Pizzuto, James; Schenk, Edward R.; Hupp, Cliff R.; Gellis, Allen; Noe, Greg; Williamson, Elyse; Karwan, Diana L.; O'Neal, Michael; Marquard, Julia; Aalto, Rolf; Newbold, Denis

2014-01-01

164

Performance Characteristics and Comparison of Abbott and artus Real-Time Systems for Hepatitis B Virus DNA Quantification ?  

PubMed Central

Virological monitoring of hepatitis B virus (HBV) DNA is critical to the management of HBV infection. With several HBV DNA quantification assays available, it is important to use the most efficient testing system for virological monitoring. In this study, we evaluated the performance characteristics and comparability of three HBV DNA quantification systems: Abbott HBV real-time PCR (Abbott PCR), artus HBV real-time PCR with QIAamp DNA blood kit purification (artus-DB), and artus HBV real-time PCR with the QIAamp DSP virus kit purification (artus-DSP). The lower limits of detection of these systems were established against the WHO international standards for HBV DNA and were found to be 1.43, 82, and 9 IU/ml, respectively. The intra-assay and interassay coefficients of variation of plasma samples (1 to 6 log10 IU/ml) ranged between 0.05 to 8.34% and 0.16 to 3.48% for the Abbott PCR, 1.53 to 26.85% and 0.50 to 12.89% for artus-DB, and 0.29 to 7.42% and 0.94 to 3.01% for artus-DSP, respectively. Ninety HBV clinical samples were used for comparison of assays, and paired quantitative results showed strong correlation by linear regression analysis (artus-DB with Abbott PCR, r = 0.95; Abbott PCR with artus-DSP, r = 0.97; and artus-DSP with artus-DB, r = 0.94). Bland-Altman analysis showed a good level of agreement for Abbott PCR and artus-DSP, with a mean difference of 0.10 log10 IU/ml and limits of agreement of ?0.91 to 1.11 log10 IU/ml. No genotype-specific bias was seen in all three systems for HBV genotypes A, C, and D, which are predominant in this region. This finding illustrates that the Abbott real-time HBV and artus-DSP systems show more comparable performance than the artus-DB system, meeting the current guidelines for assays to be used in the management of hepatitis B. PMID:21795507

Ismail, Ashrafali M.; Sivakumar, Jayashree; Anantharam, Raghavendran; Dayalan, Sujitha; Samuel, Prasanna; Fletcher, Gnanadurai J.; Gnanamony, Manu; Abraham, Priya

2011-01-01

165

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

2012-01-01

166

Changes in microarchitectural characteristics at the tibial epiphysis induced by collagen-induced rheumatoid arthritis over time  

PubMed Central

Background Little is known about the time course of changes in the microarchitecture of the tibial epiphysis with rheumatoid arthritis (RA), although such information would be valuable in predicting risk of fracture. Therefore, we used in vivo microcomputed tomography (?-CT) to assess patterns of microarchitectural alterations in the tibial epiphysis using collagen-induced RA in an animal model. Methods Bovine type II collagen was injected intradermally into the tails of rats for induction of RA. The tibial joints were scanned by in vivo ?-CT at 0, 4, and 8 weeks following injection. Microarchitectural parameters were measured to evaluate alteration patterns of bone microarchitecture at the tibial epiphysis. Results The microarchitectural alterations in an RA group were significantly different from those in a control group from 0 to 4 weeks and from 4 to 8 weeks following injection (P < 0.05). The distribution of trabecular bone thickness and trabecular bone separation from 0 weeks to 8 weeks differed significantly (P < 0.05). Conclusion These results indicate that the patterns of microarchitectural alterations at the tibial epiphysis are strongly affected by collagen-induced progression of RA and entail a severe risk of fracture at the tibial epiphysis. This study represents a valuable first approach to tracking periodic and continuous changes in the microarchitectural characteristics of the tibial epiphysis with collagen-induced RA. PMID:23049249

Lee, Joo Hyung; Chun, Keyoung Jin; Kim, Han Sung; Kim, Sang Ho; Lee, Kwon-Yong; Kim, Dae Jun; Lim, Dohyung

2012-01-01

167

Comparing single vehicle and multivehicle fatal road crashes: a joint analysis of road conditions, time variables and driver characteristics.  

PubMed

The difference between single vehicle crashes and multivehicle crashes was investigated in a collection of fatal crashes from six European countries. Variables with respect to road conditions, time variables, and participant characteristics were studied separately at first and then jointly in a logistic multiple regression model allowing to weigh different accounts of single vehicle as opposed to multivehicle crash occurrence. The most important variables to differentiate between single and multivehicle crashes were traffic flow, the presence of a junction and the presence of a physical division between carriageways. Heavy good vehicles and motorcycles were less likely to be involved in single vehicle crashes than cars. Moreover crashes of impaired drivers with more passengers were more likely to be single vehicle crashes than those of other drivers. Young drivers, rural roads, nights and weekends were all shown to have a higher proportion of single vehicle crashes but in the multivariate analysis these effects were demonstrated to be mediated by the road conditions named above. PMID:23622842

Martensen, Heike; Dupont, Emmanuelle

2013-11-01

168

Time 2 tlk 2nite: use of electronic media by adolescents during family meals and associations with demographic characteristics, family characteristics, and foods served.  

PubMed

We examined the frequency of adolescents' use of electronic media (ie, television/movie watching, text messaging, talking on the telephone, listening to music with headphones, and playing with hand-held games) at family meals and examined associations with demographic characteristics, rules about media use, family characteristics, and the types of foods served at meals using an observational, cross-sectional design. Data were drawn from two coordinated, population-based studies of adolescents (Project Eating Among Teens 2010) and their parents (Project Families and Eating Among Teens). Surveys were completed during 2009-2010. Frequent television/movie watching during family meals by youth was reported by 25.5% of parents. Multivariate logistic regression analyses indicated significantly higher odds of mealtime media use (P<0.05) for girls and older teens. In addition, higher odds of mealtime media use (P<0.05) were also seen among those whose parents had low education levels or were black or Asian; having parental rules about media use significantly reduced these odds. Frequent mealtime media use was significantly associated with lower scores on family communication (P<0.05) and scores indicating less importance placed on mealtimes (P<0.001). Furthermore, frequent mealtime media use was associated with lower odds of serving green salad, fruit, vegetables, 100% juice, and milk at meals, whereas higher odds were seen for serving sugar-sweetened beverages (P<0.05). The ubiquitous use of mealtime media by adolescents and differences by sex, race/ethnicity, age, and parental rules suggest that supporting parents in their efforts to initiate and follow-through on setting mealtime media use rules may be an important public health strategy. PMID:24361006

Fulkerson, Jayne A; Loth, Katie; Bruening, Meg; Berge, Jerica; Eisenberg, Marla E; Neumark-Sztainer, Dianne

2014-07-01

169

Characteristic 0 Positive characteristic  

E-print Network

Characteristic 0 Positive characteristic Unlikely formal intersections Piotr Kowalski Instytut Matematyczny Uniwersytetu Wroclawskiego June 14, 2012 Kowalski Unlikely formal intersections #12;Characteristic(A) + dim(V ) - dim(W). Kowalski Unlikely formal intersections #12;Characteristic 0 Positive characteristic

Kowalski, Piotr

170

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

171

Prevalence and Site Characteristics of Dental Caries in Primary Molar Teeth from Prehistoric Times to the 18th Century in England  

Microsoft Academic Search

A total of 1,974 primary molar teeth from the skeletal remains of 373 children from Prehistoric times to the 18th century were examined for caries prevalence and site characteristics. Results showed that caries in primary teeth was initiated more often at the cemento-enamel junction than the contact point in most time periods and that caries prevalence values recorded were comparable

E. A. O’Sullivan; S. A. Williams; R. C. Wakefield; J. E. Cape; M. E. J. Curzon

1993-01-01

172

Direct Observations in the Dusk Hours of the Characteristics of the Storm Time Ring Current Particles During the Beginning of Magnetic Storms  

Microsoft Academic Search

The characteristic features of the initial enhancement of the storm time ring current particles in the evening hours are consistent with flow patterns resulting from a combination of inward convection, gradient drift, and corotation, which carries plasma sheet protons into low L values near midnight and the higher-energy proton component into the plasmasphere and through the evening hours. Data from

Paul H. Smith; R. A. Hoffman

1974-01-01

173

Real-time characteristic impedance monitoring for end-point and anomaly detection in the plasma etching process  

NASA Astrophysics Data System (ADS)

We propose a practical and highly sensitive characteristic impedance monitoring (CIM) system for detecting the etching end point and anomalies during the plasma etching process. The CIM system employs a directional coupler and a newly developed vector processing system. The etching end point was successfully detected when a SiO2/Si wafer was etched with CF4 plasma; the system also detected wafer fluttering occurring during SF6-N2 plasma etching. The reactance component of the characteristic impedance primarily changed with the transient response of the electric potential on the inner glass surface during SF6-N2 plasma etching.

Motomura, Taisei; Kasashima, Yuji; Uesugi, Fumihiko; Kurita, Hiroyuki; Kimura, Naoya

2014-01-01

174

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

175

Characteristic precipitation patterns of El Niño\\/La Niña in time-variable gravity fields by GRACE  

Microsoft Academic Search

El Niño and La Niña are known to bring about characteristic patterns of anomalous precipitation in various regions of the world. We extracted temporary and regional gravity changes from monthly gravity fields recovered by the GRACE satellites, and converted them to the changes in surface mass, possibly ground or subsurface water in land area. Such mass changes in the 2006–2007

Yu Morishita; Kosuke Heki

2008-01-01

176

Effects of transportation time, distance, stocking density, temperature and lairage time on incidences of pale soft exudative (PSE) and the physico-chemical characteristics of pork.  

PubMed

The study determined the effects of transportation time, distance, stocking density, temperature and lairage time on incidences of PSE and pork quality. Frequencies of PSE cases in stocking density categories within transport duration classes were determined. General linear models, regression and the principal component (PC) analysis were used to analyse the data. Highest incidences of PSE were recorded in autumn season while lowest incidences were recorded in the spring season. Transportation time and stocking density significantly affected pHu and ultimately PSE incidences although there were no interactive effects. Highest risks of PSE occurrence were observed with more space allowance. The highest incidences of PSE were observed for animals that had travelled for two hours while the PSE cases were lower in animals that travelled for longer times. Distance travelled and transportation time had significant effects (P<0.05) on thawing loss (TL) % of pork. No relationships were reported between the other pre-slaughter variables and pork quality attributes. With the exception of transportation time and distance travelled which had a positive relationship with TL%, variation in other pre-slaughter variables did not affect meat quality variables. The risks of PSE occurrence were dependent on stocking density and transportation time. PMID:23793088

Gajana, C S; Nkukwana, T T; Marume, U; Muchenje, V

2013-11-01

177

Time?  

NASA Astrophysics Data System (ADS)

The concept of time in the `clockwork' Newtonian world was irrelevant; and has generally been ignored until recently by several generations of physicists since the implementation of quantum mechanics. We will set aside the utility of time as a property relating to physical calculations of events relating to a metrics line element or as an aspect of the transformation of a particles motion/interaction in a coordinate system or in relation to thermodynamics etc., i.e. we will discard all the usual uses of time as a concept used to circularly define physical parameters in terms of other physical parameters; concentrating instead on time as an aspect of the fundamental cosmic topology of our virtual reality especially as it inseparably relates to the nature and role of the observer in natural science.

Amoroso, Richard L.

2013-09-01

178

Waiting to see the specialist: patient and provider characteristics of wait times from primary to specialty care  

PubMed Central

Background Wait times are an important measure of access to various health care sectors and from a patient’s perspective include several stages in their care. While mechanisms to improve wait times from specialty care have been developed across Canada, little is known about wait times from primary to specialty care. Our objectives were to calculate the wait times from when a referral is made by a family physician (FP) to when a patient sees a specialist physician and examine patient and provider factors related to these wait times. Methods Our study used the Electronic Medical Record Administrative data Linked Database (EMRALD) which is a linkage of FP electronic medical record (EMR) data to the Ontario, Canada administrative data. The EMR referral date was linked to the administrative physician claims date to calculate the wait times. Patient age, sex, socioeconomic status, comorbidity and FP continuity of care and physician age, sex, practice location, practice size and participation in a primary care delivery model were examined with respect to wait times. Results The median waits from medical specialists ranged from 39 to 76 days and for surgical specialists from 33 days to 66 days. With a few exceptions, patient factors were not associated with wait times from primary care to specialty care. Similarly physician factors were not consistently associated with wait times, except for FP practice location and size. Conclusions Actual wait times for a referral from a FP to seeing a specialist physician are longer than those reported by physician surveys. Wait times from primary to specialty care need to be included in the calculation of surgical and diagnostic wait time benchmarks in Canada. PMID:24460619

2014-01-01

179

Langmuir probe measurements in a time-fluctuating-highly ionized non-equilibrium cutting arc: Analysis of the electron retarding part of the time-averaged current-voltage characteristic of the probe  

SciTech Connect

This work describes the application of Langmuir probe diagnostics to the measurement of the electron temperature in a time-fluctuating-highly ionized, non-equilibrium cutting arc. The electron retarding part of the time-averaged current-voltage characteristic of the probe was analysed, assuming that the standard exponential expression describing the electron current to the probe in collision-free plasmas can be applied under the investigated conditions. A procedure is described which allows the determination of the errors introduced in time-averaged probe data due to small-amplitude plasma fluctuations. It was found that the experimental points can be gathered into two well defined groups allowing defining two quite different averaged electron temperature values. In the low-current region the averaged characteristic was not significantly disturbed by the fluctuations and can reliably be used to obtain the actual value of the averaged electron temperature. In particular, an averaged electron temperature of 0.98 ± 0.07 eV (= 11400 ± 800 K) was found for the central core of the arc (30 A) at 3.5 mm downstream from the nozzle exit. This average included not only a time-average over the time fluctuations but also a spatial-average along the probe collecting length. The fitting of the high-current region of the characteristic using such electron temperature value together with the corrections given by the fluctuation analysis showed a relevant departure of local thermal equilibrium in the arc core.

Prevosto, L.; Mancinelli, B. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina)] [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina) [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina)

2013-12-15

180

Langmuir probe measurements in a time-fluctuating-highly ionized non-equilibrium cutting arc: analysis of the electron retarding part of the time-averaged current-voltage characteristic of the probe.  

PubMed

This work describes the application of Langmuir probe diagnostics to the measurement of the electron temperature in a time-fluctuating-highly ionized, non-equilibrium cutting arc. The electron retarding part of the time-averaged current-voltage characteristic of the probe was analysed, assuming that the standard exponential expression describing the electron current to the probe in collision-free plasmas can be applied under the investigated conditions. A procedure is described which allows the determination of the errors introduced in time-averaged probe data due to small-amplitude plasma fluctuations. It was found that the experimental points can be gathered into two well defined groups allowing defining two quite different averaged electron temperature values. In the low-current region the averaged characteristic was not significantly disturbed by the fluctuations and can reliably be used to obtain the actual value of the averaged electron temperature. In particular, an averaged electron temperature of 0.98 ± 0.07 eV (= 11400 ± 800 K) was found for the central core of the arc (30 A) at 3.5 mm downstream from the nozzle exit. This average included not only a time-average over the time fluctuations but also a spatial-average along the probe collecting length. The fitting of the high-current region of the characteristic using such electron temperature value together with the corrections given by the fluctuation analysis showed a relevant departure of local thermal equilibrium in the arc core. PMID:24387432

Prevosto, L; Kelly, H; Mancinelli, B

2013-12-01

181

Do Diligent Students Perform Better? Complex Relations between Student and Course Characteristics, Study Time, and Academic Performance in Higher Education  

ERIC Educational Resources Information Center

Research has reported equivocal results regarding the relationship between study time investment and academic performance in higher education. In the setting of the active, assignment-based teaching approach at Hasselt University (Belgium), the present study aimed (a) to further clarify the role of study time in academic performance, while taking…

Masui, Chris; Broeckmans, Jan; Doumen, Sarah; Groenen, Anne; Molenberghs, Geert

2014-01-01

182

Effects of polychlorinated biphenyls and nutritional restriction on barbituate-induced sleeping times and selected blood characteristics in raccoons (Procyon lotor)  

SciTech Connect

Hepatic microsomal enzyme activity was induced in wild-trapped raccoons (Procyon lotor) and selected blood characteristics were measured in an effort to detect responses due to PCB ingestion, nutritional restriction, and their interactions. Barbiturate-induced sleeping times were used as an index of hepatic microsomal activity because they have been used reliably by other workers. Blood characteristics examined in the study were nonesterified fatty acids (NEFA), cholesterol, and three ketone bodies (D-(-)-3-hydroxybutyrate, acetoacetate, and acetone). Results show a reduction in sleeping times, elevated NEFA and D-(-)-3-hydroxybutyrate concentrations, and lower cholesterol concentrations in PCB-treated groups. A highly significant interaction between PCB treatment and nutritional restriction was observed in acetoacetate concentrations. (JMT)

Montz, W.E.; Card, W.C.; Kirkpatrick, R.L.

1982-05-01

183

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. PMID:20455123

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

2011-01-01

184

Development of the Glenn Heat-Transfer (Glenn-HT) Computer Code to Enable Time-Filtered Navier-Stokes (TFNS) Simulations and Application to Film Cooling on a Flat Plate Through Long Cooling Tubes  

NASA Technical Reports Server (NTRS)

Computational fluid dynamics (CFD) analysis using Reynolds-averaged Navier-Stokes (RANS) formulation for turbomachinery-related flows has enabled improved engine component designs. RANS methodology has limitations that are related to its inability to accurately describe the spectrum of flow phenomena encountered in engines. Examples of flows that are difficult to compute accurately with RANS include phenomena such as laminar/turbulent transition, turbulent mixing due to mixing of streams, and separated flows. Large eddy simulation (LES) can improve accuracy but at a considerably higher cost. In recent years, hybrid schemes that take advantage of both unsteady RANS and LES have been proposed. This study investigated an alternative scheme, the time-filtered Navier-Stokes (TFNS) method applied to compressible flows. The method developed by Shih and Liu was implemented in the Glenn-Heat-Transfer (Glenn-HT) code and applied to film-cooling flows. In this report the method and its implementation is briefly described. The film effectiveness results obtained for film cooling from a row of 30deg holes with a pitch of 3.0 diameters emitting air at a nominal density ratio of unity and two blowing ratios of 0.5 and 1.0 are shown. Flow features under those conditions are also described.

Ameri, Ali; Shyam, Vikram; Rigby, David; Poinsatte, Phillip; Thurman, Douglas; Steinthorsson, Erlendur

2014-01-01

185

A High-Resolution Characteristics-Based Implicit Dual Time-Stepping VOF Method for Free Surface Flow Simulation on Unstructured Grids  

Microsoft Academic Search

In this paper, a new unstructured-grid\\/finite volume incompressible Navier–Stokes solver, based on a high-order characteristics-based method, the artificial compressibility method, and a matrix-free implicit dual time-stepping scheme, has been developed to study unsteady free surface flows. The free surface effects are calculated using the volume of fluid (VOF) method and continuum surface force. The transport equation for the VOF is

Yong Zhao; Hsiang Hui Tan; Baili Zhang

2002-01-01

186

Effect of post-mortem time on post-thaw characteristics of Spanish ibex ( Capra pyrenaica) spermatozoa  

Microsoft Academic Search

Viable epididymal sperm can be obtained in the Spanish ibex during 24h after death, but it has been observed a significant effect of the post-mortem time on fertility success, so only goats inseminated with semen recovery during the first 8h became pregnant. The aim of this study was to determine the effect of post-mortem time on epididymal semen samples from

M. R. Fernández-Santos; A. J. Soler; M. Ramón; J. L. Ros-Santaella; A. Maroto-Morales; O. García-Álvarez; A. Bisbal; J. J. Garde; M. A. Coloma; J. Santiago-Moreno

187

FPGA-based real-time emulation of power electronic systems with detailed representation of device characteristics  

Microsoft Academic Search

This paper presents a Field Programmable Gate Ar- ray (FPGA) based real-time digital simulator for power electronic apparatus based on an realistic device-level behavioral model. A 3-level 12-pulse Voltage Source Converter (VSC) fed induction machine drive is implemented on the FPGA. The VSC model is computed at a fixed time-step of 12.5ns allowing an realistic representation of the IGBT nonlinear

Aung Myaing; Venkata Dinavahi

2011-01-01

188

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

189

Characteristics of THz carrier dynamics in GaN thin film and ZnO nanowires by temperature dependent terahertz time domain spectroscopy measurement  

NASA Astrophysics Data System (ADS)

We present a comprehensive study of the characteristics of carrier dynamics using temperature dependent terahertz time domain spectroscopy. By utilizing this technique in combination with numerical calculations, the complex refractive index, dielectric function, and conductivity of n-GaN, undoped ZnO NWs, and Al-doped ZnO NWs were obtained. The unique temperature dependent behaviors of major material parameters were studied at THz frequencies, including plasma frequency, relaxation time, carrier concentration and mobility. Frequency and temperature dependent carrier dynamics were subsequently analyzed in these materials through the use of the Drude and the Drude-Smith models.

Balci, Soner; Baughman, William; Wilbert, David S.; Shen, Gang; Kung, Patrick; Kim, Seongsin Margaret

2012-12-01

190

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

2012-08-01

191

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

192

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

193

Time trends of clinical characteristics in hepatocellular carcinoma patients with chronic hepatitis B virus infection: A field survey between 2000 and 2012  

PubMed Central

The hepatitis B virus (HBV) carrier rate has decreased in Japan; however, the incidence of HBV infection among hepatocellular carcinoma (HCC) patients has not decreased accordingly. In this study, we aimed to assess the time trends of the clinical characteristics in HCC patients with chronic HBV infection. Between 2000 and 2012, we enrolled a total of 156 HCC patients with chronic HBV infection in our field survey. The HCC risk was evaluated using the HCC prediction score, which is constructed from the characteristics of age, presence of liver cirrhosis and serum levels of albumin, bilirubin and HBV DNA. Lifestyle factors and the presence of diabetes mellitus were also evaluated. The time trends of patient characteristics were analyzed using the Jonckheere-Terpstra proportion trend test. Among HCC patients with chronic HBV infection, the proportion of patients at high risk according to the HCC prediction score significantly decreased during the study period (P=0.0005). Similarly, the proportion of patients with liver cirrhosis, ?3.5 g/dl serum albumin level, >4 log copies/ml serum HBV DNA level and ?60 g/day alcohol intake were also significantly decreased. The proportion of male and obese patients was not significantly altered, whereas the proportion of elderly (?65 years) and diabetic patients tended to increase during the study period (P=0.0654 and P=0.0528, respectively). In this study, we analyzed the time trends of the clinical characteristics in HCC patients with chronic HBV infection and demonstrated that aging and diabetes mellitus may be involved in the hepatocarcinogenesis in patients with chronic HBV infection.

AMANO, KEISUKE; KAWAGUCHI, TAKUMI; KUROMATSU, RYOKO; KAWAGUCHI, ATSUSHI; MIYAJIMA, ICHIRO; IDE, TATSUYA; KAKUMA, TATSUYUKI; SATA, MICHIO

2014-01-01

194

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

195

Variations on a Theme: Characteristics of Out-of-School Time Science Programs Offered by Distinct Organization Types  

ERIC Educational Resources Information Center

The out-of-school time (OST) domain offers a promising resource for enriching young people's experience of science, technology, and engineering. Belief is widespread that OST programs are ideal locations in which to learn science and that youth participation may increase access to science for underrepresented groups, such as girls or minorities,…

Laursen, Sandra L.; Thiry, Heather; Archie, Tim; Crane, Rebecca

2013-01-01

196

The Effect of Loans on Time to Doctorate Degree: Differences by Race/Ethnicity, Field of Study, and Institutional Characteristics  

ERIC Educational Resources Information Center

Much of the focus of research on the impact of financial aid (debt in particular) has focused on undergraduate students. It is equally important to understand the impact of financial aid on graduate students, particularly since graduate students incur much higher levels of debt due to their prolonged time in higher education and because the rate…

Kim, Dongbin; Otts, Cindy

2010-01-01

197

Soft breakdown characteristics of ultralow-k time-dependent dielectric breakdown for advanced complementary metal-oxide semiconductor technologies  

Microsoft Academic Search

During technology development, the study of ultralow-k (ULK) time-dependent dielectric breakdown (TDDB) is important for assuring robust reliability. As the technology advances, the increase in ULK leakage current noise level and reversible current change induced by soft breakdown (SBD) during stress has been observed. In this paper, the physical origin of SBD and reversible breakdown, and its correlation to conventional

Fen Chen; Michael Shinosky

2010-01-01

198

Effect of post-mortem time on post-thaw characteristics of Spanish ibex (Capra pyrenaica) spermatozoa.  

PubMed

Viable epididymal sperm can be obtained in the Spanish ibex during 24h after death, but it has been observed a significant effect of the post-mortem time on fertility success, so only goats inseminated with semen recovery during the first 8h became pregnant. The aim of this study was to determine the effect of post-mortem time on epididymal semen samples from of Spanish ibex. For this purpose, sperm samples from 36 males were collected at different post-mortem times, from 2 to 24h, and cryopreserved. Thawed samples were incubated for 2h at 37°C without dilution or after dilution in a modified Tyrode medium, in order to study the sperm resistance to dilution. Moreover, flow cytometry was used to assess the sperm viability (PI), phospolipid disorder of the plasma membrane (M540), mitochondrial membrane potential (Mitotracker Deep Red), indirect apoptosis markers (YOPRO-1) and sperm chromatin stability (SCSA(®)). Sperm motility was evaluated by computer-assisted sperm analysis (CASA). Our results have shown that post-mortem time caused a reduction in mitochondrial membrane potential. In this regard, the loss of energy could be responsible for the loss of maintenance of the membrane with a consequent increase in permeability leading to a decrease in sperm viability and motility, losing linearity and speed. Moreover, the loss of maintenance of the membrane influence the extent to which sperm will survive the cryopreservation process, as it shows the results obtained from the dilution-incubation resistance test. Finally, one important finding of this study is the demonstration of no effect of post-mortem time on post-thaw DNA integrity, giving us the possibility of using sperm samples from valuable males, even if it was not possible to process during the first 8h. PMID:22014412

Fernández-Santos, M R; Soler, A J; Ramón, M; Ros-Santaella, J L; Maroto-Morales, A; García-Álvarez, O; Bisbal, A; Garde, J J; Coloma, M A; Santiago-Moreno, J

2011-11-01

199

Study on characteristics of CdS quantum dot-sensitized solar cells prepared by successive ionic layer adsorption and reaction with different adsorption times  

NASA Astrophysics Data System (ADS)

Cadmium sulfide (CdS) quantum dots (QDs) were adsorbed on a titanium dioxide (TiO2) nanoporous film by successive ionic layer adsorption and reaction (SILAR) method with different adsorption times to study the influences of different SILAR adsorption times on CdS quantum dot-sensitized solar cells (QDSCs). The optical properties of CdS sensitized TiO2 films were studied by scanning electron microscopy and UV-Vis absorbance spectroscopy. The particle size of the CdS QDs was approximated using the effective mass approximation theory from the absorbance spectra. The photovoltaic characteristics of the CdS QDSCs were analyzed by I- V characteristics and electrochemical impedance spectroscopy under air mass 1.5 illumination. As a result, the particle size of the CdS QDs became larger and light harvesting was enhanced with increasing SILAR adsorption time. The maximum photovoltaic conversion efficiency of the CdS QDSCs (1.86%) was obtained at the SILAR adsorption time of 30 min with the highest short circuit current density and lowest charge transfer resistance.

Jeong, Myeong-Soo; Son, Min-Kyu; Kim, Soo-Kyoung; Park, Songyi; Prabakar, Kandasamy; Kim, Hee-Je

2014-05-01

200

Effects of the hydraulic retention time on the fouling characteristics of an anaerobic membrane bioreactor for treating acidifi ed wastewater  

Microsoft Academic Search

This study focused on the effect of hydraulic retention time (HRT) effect on microbial activity and fouling potential in submerged anaerobic membrane bioreactors (AMBRs).Three submerged AMBRs were operated at HRT of 14, 16, and 20 days with polypropylene U-shaped hollow fiber microfiltration membranes (nominal pore size = 0.45 ?m; effective filtration area = 0.003 m2). Extracellular polymeric substances (EPS) and

Emma Jeong; Hyun-Woo Kim; Joo-Youn Nam; Yong-Tae Ahn; Hang-Sik Shin

2010-01-01

201

A Methodology for Flight-Time Identification of Helicopter-Slung Load Frequency Response Characteristics Using CIFER  

NASA Technical Reports Server (NTRS)

Helicopter slung load operations are common in both military and civil contexts. The slung load adds load rigid body modes, sling stretching, and load aerodynamics to the system dynamics, which can degrade system stability and handling qualities, and reduce the operating envelope of the combined system below that of the helicopter alone. Further, the effects of the load on system dynamics vary significantly among the large range of loads, slings, and flight conditions that a utility helicopter will encounter in its operating life. In this context, military helicopters and loads are often qualified for slung load operations via flight tests which can be time consuming and expensive. One way to reduce the cost and time required to carry out these tests and generate quantitative data more readily is to provide an efficient method for analysis during the flight, so that numerous test points can be evaluated in a single flight test, with evaluations performed in near real time following each test point and prior to clearing the aircraft to the next point. Methodology for this was implemented at Ames and demonstrated in slung load flight tests in 1997 and was improved for additional flight tests in 1999. The parameters of interest for the slung load tests are aircraft handling qualities parameters (bandwidth and phase delay), stability margins (gain and phase margin), and load pendulum roots (damping and natural frequency). A procedure for the identification of these parameters from frequency sweep data was defined using the CIFER software package. CIFER is a comprehensive interactive package of utilities for frequency domain analysis previously developed at Ames for aeronautical flight test applications. It has been widely used in the US on a variety of aircraft, including some primitive flight time analysis applications.

Sahai, Ranjana; Pierce, Larry; Cicolani, Luigi; Tischler, Mark

1998-01-01

202

X-ray spectral and timing characteristics of the stars in the young open cluster IC 2391  

E-print Network

We present X-ray spectral and timing analysis of members of the young open cluster IC 2391 observed with the XMM-Newton observatory. We detected 99 X-ray sources by analysing the summed data obtained from MOS1, MOS2 and pn detectors of the EPIC camera; 24 of them are members, or probable members, of the cluster. Stars of all spectral types have been detected, from the early-types to the late-M dwarfs. Despite the capability of the instrument to recognize up to 3 thermal components, the X-ray spectra of the G, K and M members of the cluster are well described with two thermal components (at kT$_1 \\sim$ 0.3-0.5 keV and kT$_2 \\sim$ 1.0-1.2 keV respectively) while the X-ray spectra of F members require only a softer 1-T model. The Kolmogorov-Smirnov test applied to the X-ray photon time series shows that approximately 46% of the members of IC 2391 are variable with a confidence level $>$99%. The comparison of our data with those obtained with ROSAT/PSPC, nine years earlier, and ROSAT/HRI, seven years earlier, shows that there is no evidence of significant variability on these time scales, suggesting that long-term variations due to activity cycles similar to that on the Sun are not common, if present at all, among these young stars.

A. Marino; G. Micela; G. Peres; I. Pillitteri; S. Sciortino

2004-10-05

203

Characteristics of official and experimental GRACE time series by GFZ and CSR - with applications to polar signals  

NASA Astrophysics Data System (ADS)

The Release-05 monthly solutions by the three centers of the GRACE Science and Data System are a significant improvement with respect to the previous Release 4. Meanwhile, previous assessments have revealed different noise levels between the solutions by CSR, GFZ and JPL, and also different amplitudes of interannual signal in the solutions by GFZ as compared to the two other centers. Encouraged by the science community, GFZ and CSR have kindly provided additional sets of time series. GFZ has reprocessed the RL05 monthly solutions (up to degree and order 90) with revised processing. CSR has made available monthly solutions with standard processing up to degree and order 96, in addition to their solutions up to degree and order 60. We compare these different time series with respect to their signal and noise content and analyze them on global and regional scale. For the regional scale our special interest is paid on Antarctica and on revealing polar signals such as ice mass trends and GIA. Following the necessity of destriping, an optimal choice for the setup of the Swenson & Wahr filter approach is evaluated to adapt to the specific signal and noise level in Antarctica. Furthermore we analyze the potential benefit of mixed time series solutions in order to combine the strengths of the solutions available. Concerning the question for an optimal maximum degree we suggest that for resolving large polar ice mass changes, it would be beneficial to provide gravity field variations even beyond degree 90.

Horvath, Alexander; Horwath, Martin; Pail, Roland

2014-05-01

204

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 (24 h, 48 h and 72 h) on the meat quality of tame trained to lead Hungarian Simmental bulls subjected to long commercial transportation of approximately 1800 km. A total of 30 bulls, with an average age of 24 months, were used. During the lairage, bulls received 0.5 kg concentrate feed per animal per day and ad libitum access to the hay and water. As the lairage duration increased, the pH(ult) decreased (P<0.05). Bulls lairaged for 24 h had lower L*, b* and H* values than those lairaged for 48 h and 72 h (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 pH(ult). In conclusion, 72 h 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

2014-01-01

205

Invasion percolation model for abnormal time-dependent dielectric breakdown characteristic of low-k dielectrics due to massive metallic diffusion  

NASA Astrophysics Data System (ADS)

With the continuing aggressive scaling of interconnect dimensions and introduction of lower k materials, back-end-of-line (BEOL) dielectric time-dependent dielectric breakdown (TDDB) reliability margin is greatly reduced. In this paper, a comprehensive investigation on abnormal low-k TDDB characteristics, a systematic degradation of Weibull slopes, and a systematic increase of field acceleration at lower stress voltages due to massive Cu diffusion were conducted for Cu interconnect with low-k dielectric. Based on data from extensive electrical and physical analysis, such abnormal TDDB characteristics were attributed to slow metallic diffusion in bulk low-k under bias and temperature stress. A TDDB model based on invasion percolation was proposed to model the observed abnormalities. Cu interconnects with robust liner and capping layer, to ensure metal free low-k film, have become important for BEOL low-k TDDB.

Chen, Fen; Shinosky, Michael; Aitken, John; Yang, Chih-Chao; Edelstein, Daniel

2012-12-01

206

Write-once-read-many-times characteristics of Pt/Al2O3/ITO memory devices  

NASA Astrophysics Data System (ADS)

Nonvolatile write-once-read-many-times (WORM) Pt/Al2O3/ITO memory devices prepared at room temperature were demonstrated. The WORM memory devices show irreversible transition from the initial low resistance (ON) state to the high resistance (OFF) state, high ON/OFF ratio, long data retention, and good reading endurance in air at room temperature. The high performances are promising for employing the Pt/Al2O3/ITO WORM memory devices in permanent storage of information. The nonvolatile memory behaviors could be attributed to the formation and permanent rupture of conductive filament consisting of positively charged oxygen vacancies.

Wu, Shuxiang; Chen, Xinman; Ren, Lizhu; Hu, Wei; Yu, Fengmei; Yang, Kungan; Yang, Mei; Wang, Yunjia; Meng, Meng; Zhou, Wenqi; Bao, Dinghua; Li, Shuwei

2014-08-01

207

Concentration- and time-response characteristics of plaque isolates of Agrotis ipsilon multiple nucleopolyhedrovirus derived from a field isolate.  

PubMed

Plaque isolates derived from the Illinois field isolate of Agrotis ipsilon multiple nucleopolyhedrovirus are distinguished by the presence or absence of a small deletion in the baculovirus egt (ecdysteroid UDP-glucosyltransferase) coding sequence. In concentration-response and time-response bioassays with both plaque and field isolates, plaque isolates with a mutated egt gene were less pathogenic against A. ipsilon larvae than other isolates, but killed larvae faster. Mixed infections with isolates representing the two different egt genotypes caused the same level of mortality as the field isolate and a plaque isolate with a wild-type egt gene. PMID:23220242

Harrison, Robert L

2013-02-01

208

Calibrating passive acoustic monitoring: correcting humpback whale call detections for site-specific and time-dependent environmental characteristics.  

PubMed

This paper demonstrates the importance of accounting for environmental effects on passive underwater acoustic monitoring results. The situation considered is the reduction in shipping off the California coast between 2008-2010 due to the recession and environmental legislation. The resulting variations in ocean noise change the probability of detecting marine mammal vocalizations. An acoustic model was used to calculate the time-varying probability of detecting humpback whale vocalizations under best-guess environmental conditions and varying noise. The uncorrected call counts suggest a diel pattern and an increase in calling over a two-year period; the corrected call counts show minimal evidence of these features. PMID:24181982

Helble, Tyler A; D'Spain, Gerald L; Campbell, Greg S; Hildebrand, John A

2013-11-01

209

Mestif -- a Study of the Characteristics of Matter-Energy Space-Time and Information-Field  

NASA Astrophysics Data System (ADS)

In this paper, the concept of Information-Field (IF) is proposed and discussed in relation to Matter-Energy (ME) and Space-Time (ST). IF is the system of the organization and process of potential events. IF interacts and influences mutually with ME and hence also with ST. IF is pertinent in science in general, and is particularly significant in quantum cosmology, quantum computing, genome, information theory. The increasing understanding of cosmology and genome, the advancement in the information technology and the availability of tools to manage large data sets provide the platform and impetus for further research in the field.

Tan, James A. K.

2014-04-01

210

An inductively coupled plasma-time-of-flight mass spectrometer for elemental analysis. Part I: Optimization and characteristics.  

PubMed

An inductively coupled plasma-time-of-flight mass spectrometer (ICP-TOFMS) has been constructed and evaluated for elemental analysis. The instrument produces analog spectra similar to those from quadrupole inductively coupled plasma mass spectrometers. The large abundance of Ar ions is deflected away from the microchannel plate detector to reduce detector dead time and space-charge complications. The ICP-TOFMS, operated in a linear (nonreflecting) mode, currently has a resolving power of 500 (full width at half maximum). Present ion optics employed in the instrument require a trade-off between signal-to-noise ratio and resolving power. In addition, mass-dependent kinetic energies in the supersonic beam created in the ICP mass spectrometer interface cause a mass bias in the right-angle TOFMS because the ions must be steered to the detector to compensate for their velocity in the supersonic beam direction. In the current design the sampling duty cycle is only approximately 3%, thereby limiting sensitivity. However, positive potentials applied to the right-angle extraction region can increase sensitivity by a factor of 2-4 by slowing down the ions that enter the extraction zone. The transmission efficiency of the TOFMS is approximately 20% and is limited by divergence of the ion packet in the drift tube. PMID:24226390

Myers, D P; Li, G; Yang, P; Hieftje, G M

1994-11-01

211

Characteristics and Function of AN Electron Attachment Spectrometer: Pulse Formation Time and Gain Effects in P-10 Gas  

NASA Astrophysics Data System (ADS)

An Electron Attachment Spectrometer (EAS) has been designed to measure electron attachment in air and other gases. The aim of the EAS is to observe how parameters such as the electric field, reduced electric field and type of gas can influence electron attachment. The overall objective of this work is to investigate if the gas-gain of a proportional counter can be optimized by minimizing electron attachment with oxygen to improve the measurement of tritium-in-air. Current research interests include the measurement of the time between the generation of the electron-ion pairs and arrival of the electrons at the wire anode. Additionally, the study of the multiplication properties of the detector as a function of pulse formation time, P-10 gas flow rate and electric field will be presented. The EAS is a cylinder with a length of approximately 92 mm and diameter of 41 mm comprised of cylindrical hollow brass electrodes and Teflon spacers. A uniform electric field within the tube is applied and guides electrons and/or ions towards their respective electrodes. A proportional counter with a 50 ?m diameter wire anode is used to detect the electrons and/or ions created by an 241Am source located at the opposite end.

Orchard, Gloria M.; Waker, Anthony J.

2014-02-01

212

Structural characteristic of folding/unfolding intermediate of pokeweed anti-viral protein revealed by time-resolved fluorescence.  

PubMed

The structural feature of unfolding intermediate of pokeweed anti-viral protein (PAP) was characterized using time-resolved fluorescence spectroscopic methods to elucidate protein folding/unfolding process. CD and fluorescence spectra consistently demonstrated that the unfolding of PAP completed at 4 M of guanidine hydrochloride (GuHCl). The fluorescence resonance energy transfer (FRET) and time-resolve fluorescence depolarization analysis of Trp208 and Trp237 located in the C-terminal domain of PAP suggested that peculiar unfolding intermediate populated before reaching to the unfolding state. The FRET distance of Trp237 to Tyr182 was extended to more than 28 Å with keeping the compact conformation in the unfolding intermediate state populated in the presence of 2 M GuHCl. On the other hand, Trp208 maintained the energy transfer pair with Tyr72 near the active site, although the rotational freedom was increased a little. There results suggest that the most distinguished structural feature of the unfolding intermediate of PAP is the separation of C-terminal domain from N-terminal domain. FRET and fluorescence depolarization studies also showed that C-terminal domain would be more separated to liberate the segmental motions of Trp208 and Trp237 distinctly at the unfolding state. PMID:23319009

Matsumoto, Shuzo; Taniguchi, Yuka; Fukunaga, Yukihiro; Nakashima, Hiromichi; Watanabe, Keiichi; Yamashita, Shoji; Nishimoto, Etsuko

2013-05-01

213

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

214

Modulated drug release using iontophoresis through heterogeneous cation-exchange membranes. 2. Influence of cation-exchanger content on membrane resistance and characteristic times.  

PubMed

An implantable drug delivery method using iontophoresis through cation-selective membranes was further developed. Heterogeneous cation-exchange membranes (HCMs) were prepared by mixing conductive sulfonated polystyrene beads into a nonconductive silicone rubber matrix. The membrane resistivity and lag time to steady-state transport of two salts, (+/-)-phenylpropanolamine hydrochloride (PPA) and NaCl, were evaluated during constant current iontophoresis at 37 degrees C as a function of the resin content in the HCMs. A continuous decline in membrane resistivity was observed as fractional resin content (l) was increased over the entire usable region (l = 0.29-0.52), a characteristic that could be described by a percolation scaling law (for an infinite lattice, 3-D geometry). Morphological analysis of the membranes before and after swelling strongly suggested that the conducting clusters of resin beads form during the swelling period prior to use. The response time to steady-state transport of PPA into NaCl during a 40 microA constant current (0.27 cm2) was found to increase with increasing l, but not without decreasing the permselectivity of the HCMs for the drug cation. The lag time effect could be explained in terms of an increasing number of fixed charge groups in the membrane available for transport (mfcA), which was derived from a macroscopic mass balance model. The values of mfcA were also found to be related to the characteristic time of diffusion in a homogeneous transport projection of the HCM (or an effective medium), an essential parameter for future non-steady-state simulations. The characteristic time of diffusion was found to be invariant with changing resin content, suggesting that the membranes are fairly nontortuous (ca. seven beads thick). By assuming that the thickness of the HCM approaches the thickness of its homogeneous projection, an expression was derived to predict lag time to steady-state PPA transport requiring resistance measurements only (provided that the resin capacity is known). There was excellent agreement between the theoretical and experimental lag time to steady-state transport of PPA (r = 0.96, p < 0.001), further implicating the role of membrane resistance in the bi-ionic system. These modeling approaches have already found utility in iontophoretic implant design for prevention of cardiac arrhythmias and may be valuable in future non-steady-state analysis to further develop on-line detection-implant response technology. PMID:7884674

Schwendeman, S P; Amidon, G L; Labhasetwar, V; Levy, R J

1994-10-01

215

Treatment-time regimen of hypertension medications significantly affects ambulatory blood pressure and clinical characteristics of patients with resistant hypertension.  

PubMed

Patients with resistant hypertension (RH) are at greater risk for stroke, renal insufficiency, and cardiovascular disease (CVD) events than are those for whom blood pressure (BP) is responsive to and well controlled by therapeutic interventions. Although all chronotherapy trials have compared the effects on BP regulation of full daily doses of medications when ingested in the morning versus at bedtime, prescription of the same medications in divided doses twice daily (BID) is frequent. Here, we investigated the influence of hypertension treatment-time regimen on the circadian BP pattern, degree of BP control, and relevant clinical and laboratory medicine parameters of RH patients evaluated by 48-h ambulatory BP monitoring (ABPM). This cross-sectional study evaluated 2899 such patients (1701 men/1198 women), 64.2?±?11.8 (mean?±?SD) yrs of age, enrolled in the Hygia Project. Among the participants, 1084 were ingesting all hypertension medications upon awakening (upon-awakening regimen), 1436 patients were ingesting the full daily dose of ?1 of them at bedtime (bedtime regimen), and 379 were ingesting split doses of ?1 medications BID upon awakening and at bedtime (BID regimen). Patients of the bedtime regimen compared with the other two treatment-time regimens had lower likelihood of microalbuminuria and chronic kidney disease; significantly lower albumin/creatinine ratio, glucose, total cholesterol, and low-density lipoprotein (LDL) cholesterol; plus higher estimated glomerular filtration rate and high-density lipoprotein (HDL) cholesterol. The bedtime regimen was also significantly associated with lower asleep systolic (SBP) and diastolic (DBP) BP means than the upon-awakening and BID regimens. The sleep-time relative SBP and DBP decline was significantly attenuated by the upon-awakening and BID regimens (p?time regimen groups (80.5% and 77.3%, respectively) than in the bedtime regimen (54.4%; p?

Hermida, Ramón C; Ríos, María T; Crespo, Juan J; Moyá, Ana; Domínguez-Sardiña, Manuel; Otero, Alfonso; Sánchez, Juan J; Mojón, Artemio; Fernández, José R; Ayala, Diana E

2013-03-01

216

Compliance to a cell phone-based ecological momentary assessment study: the effect of time and personality characteristics.  

PubMed

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 missing at random and bias the results of subsequent analyses. In order to use modern statistical approaches for handling missing data, it is important to include variables predicting missing values into the statistical analysis. Therefore, these predictors have to be known and measured. The authors collected data on 3 four-item mood scales measuring well-being, wakefulness, and nervousness on 6 occasions per day for 7 days (N = 305) and examined compliance rate across time, within day, and within week. Results show good global compliance (mean compliance: 74.9% of calls answered). Compliance varied more within day than within week. Within day, it was lower for the first call of the day between 9 p.m. and 11 p.m. and higher for the call between 5 p.m. and 7 p.m. Within week, calls were equally answered across days of the week, but, as the study progressed, there was a slight drop in compliance with a progressive decrease that was stronger for the first 2 calls. Compliance on the person level did not depend on personality or on satisfaction with life. Practical consequences of the results for conducting ambulatory assessment studies are discussed, and some recommendations are given. PMID:22250597

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

2012-09-01

217

[The social profile and medical characteristics of a first-time registered patient with tuberculosis of the respiratory organs].  

PubMed

Documentation concerning 307 patients with newly discovered respiratory tuberculosis during 1979-1988 was analysed. The mean age of the patients was 40. Respiratory tuberculosis morbidity among adult men was 5.3 times higher than that among women. More benign forms of the disease were revealed in the latter, which insured 100% cure among them. Half the male patients were smear-positive; 3/4, were alcohol abusers; and 1/3 were kept in reformatory institutions before the onset of the disease. Every second of them was single, thus prone to an unhealthy lifestyle and improper nutrition. 4/5 of the tuberculosis-affected men were heavy tobacco smokers with concomitant chronic bronchitis, and the death of 2% of this number was caused by concurrent lung cancer. The follow-up of 248 men from 1 month to 10 years showed that tuberculosis and other causes, including cancer, underlying diseases and fatal injuries, led to the death of 1 (0.4%) and 9.7% of the patients, respectively. PMID:2388888

Ursov, I G; Leonov, O G

1990-01-01

218

Global Characteristics of the Correlation and Time Lag Between Solar and Ionospheric Parameters in the 27-day Period  

NASA Technical Reports Server (NTRS)

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 approx. 370 km and approx. 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 processes that is not controlled by the solar extreme ultraviolet radiation.

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

2012-01-01

219

Over time and space changing characteristics of estuarine suspended particles in the German Weser and Elbe estuaries  

NASA Astrophysics Data System (ADS)

Fine cohesive, suspended sediments appear in all estuarine environments in a predominately flocculated state. The transport and deposition of these flocs is influenced by their in-situ and primary particle size distribution. Especially the size of the inorganic particles influences the density and hence the settling velocity of the flocculated material. To describe both the changes in primary particle size of suspended particulate matter as well as the variability of floc sizes over time and space, the data of In-Situ Particle-Size Distributions (ISPSDs), Primary Particle Size Distributions (PPSDs) and Suspended Sediment Concentrations (SSCs) were collected. For this, Laser In-Situ Scattering and Transmissiometry (LISST) measurements as well as the water samples were collected in the German Elbe and Weser estuaries, covering seasonal variability of the SSC. The data of the ISPSDs show that the inorganic and organic Suspended Particulate Matter (SPM), as found in the Elbe and Weser estuaries, mostly appears in a flocculated state. The substrate for organic matter is mainly imported from the seaside and transported into the estuaries as indicated by an upstream decrease of the amount of fine particles. In winter, when the freshwater discharge is high, different PPSDs are found in the case of the Elbe estuary in the Turbidity Maximum Zone (TMZ) as well as in the landward and in the seaward sections close to the TMZ. In summer, the distance between the seaward and the landward section is too low to obtain an individual PPSD within the Elbe TMZ. A missing correlation between the PPSD and ISPSD shows that the inorganic constituents do not have an influence on the in-situ floc size. Although flocs aggregate and disaggregate over a tidal cycle and with changing SSC, they do not change their PPSD. The microflocs are therefore strong enough to withstand further breakage into their inorganic constituents.

Papenmeier, Svenja; Schrottke, Kerstin; Bartholomä, Alexander

2014-01-01

220

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  

PubMed Central

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 both these behaviors, and to describe associations with age, gender, race/ethnicity, and weight status. Methods We analyzed data collected during the National Health and Nutrition Examination Surveys 2001–2004, a US nationally representative cross-sectional study. We studied 2964 children aged 4.00 to 11.99 years. Our main outcomes were reported weekly times that the child played or exercised hard enough to sweat or breathe hard (active play), daily hours the child watched television/videos, used computers, or played computer games (screen time), and the combination of low active play and high screen time. Low active play was defined as active play 6 times or less per week. High screen time was defined as more than 2 hours per day. We accounted for the complex survey design in analyses and report proportions and 95% confidence intervals. We used Wald Chi-square to test for differences between proportions. To identify factors associated with low active play and high screen time, we used multivariate logistic regression. Results Of US children aged 4 to 11 years, 37.3% (95% confidence interval, 34.1% to 40.4%) had low levels of active play, 65.0% (95% CI, 61.4% to 68.5%) had high screen time, and 26.3% (95% CI, 23.8% to 28.9%) had both these behaviors. Characteristics associated with a higher probability of simultaneously having low active play and high screen time were older age, female gender, non-Hispanic black race/ethnicity, and having a BMI-for-age ?95th percentile of the CDC growth reference. Conclusion Many young children in the US are reported to have physical activity and screen time behaviors that are inconsistent with recommendations for healthy pediatric development. Children who are overweight, approaching adolescence, girls, and non-Hispanic blacks may benefit most from public health policies and programs aimed at these behaviors. PMID:18945351

Anderson, Sarah E; Economos, Christina D; Must, Aviva

2008-01-01

221

[Leisure-time physical activities among adults in Florianopolis, state of Santa Catarina, Brazil: a population-based study on the characteristics of the practices and the practitioners].  

PubMed

The study established characteristics of practices and practitioners of leisure-time physical activities among adults in Florianopolis, Brazil. It was a population-based, cross-sectional survey conducted between September 2009 and January 2010. Leisure-time physical activity was assessed using a validated questionnaire. Walking and weight lifting were the most frequently reported activities. Vigorous physical activities were more frequent among men and young adults. There were no gender or age differences in relation to the frequency and duration of physical activities. Walking and gymnastics were more frequently practiced by women, and jogging and soccer by men. Age was positively associated with walking, and negatively with soccer and weight lifting. Caucasian and black males practiced gymnastics and soccer more frequently. Adults living with a partner practiced more walking and soccer, and less weight lifting. Educational level was directly associated with jogging and gymnastics, but inversely with soccer. Income was inversely associated with soccer and directly associated with weight lifting. Policies to promote physical activity should consider the different interests of the population to stimulate the scope of their practice in leisure-time. PMID:25351325

Del Duca, Giovâni Firpo; Nahas, Markus Vinicius; Hallal, Pedro Curi; Peres, Karen Glazer

2014-11-01

222

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

223

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

224

Direct observations in the dusk hours of the characteristics of the storm-time ring current particles during the beginning of magnetic storms  

NASA Technical Reports Server (NTRS)

The characteristic features of the initial enhancement of the storm-time ring current particles in the evening hours are consistent with flow patterns resulting from a combination of inward convection, gradient drift, and corotation which carries plasma sheet protons into low L-values near midnight and the higher energy proton component into the plasmasphere and through the evening hours. Data from four magnetic storms during the early life of Explorer 45, when the local time of apogee was in the afternoon and evening hours, show that protons with lower magnetic moments penetrate deeper into the magnetosphere until a low limit, determined by the corotation and gradient drift forces, is reached. Such particle motions produce the stable energy dependent inner boundary of the ring current protons inside the plasmapause in the dusk sector and also provide the mechanism for energy injection into the ring current region. From the analyses of the pitch angle distributions it is evident that charge exchange and wave particle interactions are not the dominant causes of this inner boundary.

Smith, P. H.; Hoffman, R. A.

1973-01-01

225

[Effect of food deprivation on quantitative and time characteristics of feeding of goldfish Carassius auratus in norm and under action of adrenaline].  

PubMed

There was studied effect of intraperitoneally administered adrenaline (0.14 mg/kg) on volume and time characteristics of feeding (duration of single, grouped, and total nutrition) of goldfish Carassius auratus (L.) previously maintained on normal and restricted (for 10 and 15 days) diet. The fish on restricted diet demonstrated the biphasic alimentary response to the adrenaline administration, similar with that in the normally fed fish: a decrease of volume, duration of the grouped and total feeding at the first phase of action of hormone and an increase--at the second phase; however, the value of the response at the first phase of the hormone action was lower, whereas at the second phase--higher than in the fish obtaining a sufficient amount of food prior to the experiment. Duration of the single feeding rose in fish of all groups including the control one, the maximum increase being observed in the goldfish submitted to food deprivation. The glycogen content in hepatopancreas of the normally fed goldfish exceeded by the end of the experiment 4.5-6 times that in the food-deprived ones. The obtained results confirm suggestion that a decrease of the level of reserve substances in the body leads to a decrease of the fish receptivity to the stress hormone--adrenaline and, hence, to a change of the value of its effects on the food-searching goldfish activity, with preservation of dynamics of the parameters. PMID:21938911

Garina, D V

2011-01-01

226

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

227

A multi-model approach to X-ray pulsars. Connecting spectral and timing models to pin down the intrinsic emission characteristics of magnetized, accreting neutron stars  

NASA Astrophysics Data System (ADS)

The emission characteristics of X-ray pulsars are governed by magnetospheric accretion within the Alfvén radius, leading to a direct coupling of accretion column properties and interactions at the magnetosphere. The complexity of the physical processes governing the formation of radiation within the accreted, strongly magnetized plasma has led to several sophisticated theoretical modelling efforts over the last decade, dedicated to either the formation of the broad band continuum, the formation of cyclotron resonance scattering features (CRSFs) or the formation of pulse profiles. While these individual approaches are powerful in themselves, they quickly reach their limits when aiming at a quantitative comparison to observational data. Too many fundamental parameters, describing the formation of the accretion columns and the systems' overall geometry are unconstrained and different models are often based on different fundamental assumptions, while everything is intertwined in the observed, highly phase-dependent spectra and energy-dependent pulse profiles. To name just one example: the (phase variable) line width of the CRSFs is highly dependent on the plasma temperature, the existence of B-field gradients (geometry) and observation angle, parameters which, in turn, drive the continuum radiation and are driven by the overall two-pole geometry for the light bending model respectively. This renders a parallel assessment of all available spectral and timing information by a compatible across-models-approach indispensable. In a collaboration of theoreticians and observers, we have been working on a model unification project over the last years, bringing together theoretical calculations of the Comptonized continuum, Monte Carlo simulations and Radiation Transfer calculations of CRSFs as well as a General Relativity (GR) light bending model for ray tracing of the incident emission pattern from both magnetic poles. The ultimate goal is to implement a unified fitting model for phase-resolved spectral and timing data analysis. We present the current status of this project.

Schönherr, G.; Schwarm, F.; Falkner, S.; Becker, P.; Wilms, J.; Dauser, T.; Wolff, M. T.; Wolfram, K.; West, B.; Pottschmidt, K.; Kretschmar, P.; Ferrigno, C.; Klochkov, D.; Nishimura, O.; Kreykenbohm, I.; Caballero, I.; Staubert, R.

2014-01-01

228

Enhancement Characteristics and Impact on Image Quality of Two Gadolinium Chelates at Equimolar Doses for Time-Resolved 3-Tesla MR-Angiography of the Calf Station  

PubMed Central

Purpose To compare enhancement characteristics and image quality of two macrocyclic gadolinium chelates, gadoterate meglumine and gadobutrol, in low-dose, time-resolved MRA of the calf station. Materials and Methods 100 consecutive patients with peripheral arterial disease (stages II-IV) were retrospectively analysed. Fifty patients were included in each group - 32 men and 18 women for gadobutrol (mean age 67 years) and 34 men, 16 women for gadoterate meglumine (mean age 64 years). 0.03 mmol/kg bw of either gadobutrol or gadoterate meglumine was injected. Gadobutrol was diluted 1?1 with normal saline (0.9% NaCl) to provide similar injection volume and bolus geometry compared to the undiluted 0.5 M dose of gadoterate meglumine. Signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR) and image quality were analysed and compared between the two groups. Results Mean SNR ranged from 83.0±46.7 (peroneal artery) to 96.4±64.5 (anterior tibial artery) for gadobutrol, and from 37.6±13.8 (peroneal artery) to 45.3±16.4 (anterior tibial artery) for the gadoterate meglumine group (p<0.0001). CNR values ranged from 30.1±20.1 (peroneal artery) to 37.6±26.0 (anterior tibial artery) for gadobutrol and from 14.9±8.0 (peroneal artery) to 18.6±16.4 (anterior tibial artery) for gadoterate meglumine (p<0.0001). No significant difference in image quality was found except for the peroneal arteries (p?=?0.006 and p?=?0.04). Interreader agreement was excellent (kappa 0.87–0.93) Conclusion The significantly better enhancement as assessed by SNR and CNR provided by gadobutrol compared to gadoterate meglumine does not translate into substantial differences in image quality in an equimolar, low-dose, time-resolved MRA protocol of the calves. PMID:24893292

Hansmann, Jan; Michaely, Henrik J.; Morelli, John N.; Luckscheiter, Andre; Schoenberg, Stefan O.; Attenberger, Ulrike I.

2014-01-01

229

Long-term impact of anaerobic reaction time on the performance and granular characteristics of granular denitrifying biological phosphorus removal systems.  

PubMed

Removal of nitrogen and phosphorus (P) from wastewater is successfully and widely practiced in systems employing both granular sludge technology and enhanced biological P removal (EBPR) processes; however, the key parameter, anaerobic reaction time (AnRT), has not been thoroughly investigated. Successful EBPR is highly dependent on an appropriate AnRT, which induces carbon and polyphosphate metabolism by phosphorus accumulating organisms (PAOs). Therefore, the long-term impact of AnRT on denitrifying P removal performance and granular characteristics was investigated in three identical granular sludge sequencing batch reactors with AnRTs of 90 (R1), 120 (R2) and 150 min (R3). The microbial community structures and anaerobic stoichiometric parameters related to various AnRTs were monitored over time. Free nitrite acid (FNA) accumulation (e.g., 0.0008-0.0016 mg HNO2-N/L) occurred frequently owing to incomplete denitrification in the adaptation period, especially in R3, which influenced the anaerobic/anoxic intracellular intermediate metabolites and activities of intracellular enzymes negatively, resulting in lower levels of poly-P and reduced activity of polyphosphate kinase. As a result, the Accumulibacter-PAOs population decreased from 51 ± 2.5% to 43 ± 2.1% when AnRT was extended from 90 to 150 min, leading to decreased denitrifying P removal performance. Additionally, frequent exposure of microorganisms to the FNA accumulation and anaerobic endogenous conditions in excess AnRT cases (e.g., 150 min) stimulated increased extracellular polymeric substances (EPS) production by microorganisms, resulting in enhanced granular formation and larger granules (size of 0.6-1.2 mm), but decreasing anaerobic PHA synthesis and glycogen hydrolysis. Phosphorus removal capacity was mediated to some extent by EPS adsorption in granular sludge systems that possessed more EPS, longer AnRT and relatively higher GAOs. PMID:23863379

Wang, Yayi; Guo, Gang; Wang, Hong; Stephenson, Tom; Guo, Jianhua; Ye, Liu

2013-09-15

230

Time-dependent characteristics of the dielectric barrier discharge in Xe-Cl2 mixture and kinetics of the XeCl? molecules  

NASA Astrophysics Data System (ADS)

Time-dependent characteristics of the dielectric barrier discharge in Xe-Cl2 mixture at chlorine concentration of 0.5% and kinetic processes governing the generation of XeCl? molecules are studied using the 1D fluid model. It is shown that at low voltage amplitude (5 kV) a one-peak mode of the discharge is observed and at high voltage amplitude (7 kV) a two-peak mode of the discharge appears. The radiation power of the XeCl? band increases with amplitude of the supply voltage. It is demonstrated that the harpoon reaction Xe? + Cl2 ? XeCl? + Cl provides the greatest contribution into generation of XeCl? exciplex molecules during short current pulses and the ion-ion recombination Xe+ 2 + Cl- ? XeCl* + Xe provides the greatest contribution during afterglow. Quenching of XeCl? molecules is a result of the radiative decay XeCl? ? Xe + Cl + hv (308 nm). During current spike the great contribution into quenching of XeCl? provides also the dissociative ionization e + XeCl? ? Xe+ + Cl + 2e.

Avtaeva, Svetlana

2014-04-01

231

Effect of pre-slaughter management regarding transportation and time in lairage on certain stress parameters, carcass and meat quality characteristics in Kivircik lambs.  

PubMed

Thirty Kivircik lambs were used to investigate effect of pre-slaughter treatment on certain haematological and biochemical parameters, carcass and meat quality characteristics. Lambs were divided into three treatments: 75 min transport and lairage for 18 h (TS-L18 h); 75 min transport and lairage for 30 min (TS-L30 min) and no pre-slaughter transport and lairage for 30 min (NTS). Treatment, as a main effect, did not influence haematological and biochemical parameters, but sampling time significantly affected these parameters, except total protein. Plasma cortisol concentration at exsanguination in TS-18 h, TS-30 min and NTS treatments were 117.34, 119.23 and 72.51 ng/ml, respectively. pH of longissimus dorsi muscle was higher in TS-L30 min than other treatments. TS-L30 min lambs had the highest shear force value, the lowest WHC and cooking loss. TS-L30 min treatment yielded the darkest meat immediately after cutting and 1 h later. Meat redness, yellowness and chroma values were similar in treatments. PMID:22197098

Ekiz, Bulent; Ekiz, Elif Ergul; Kocak, Omur; Yalcintan, Hulya; Yilmaz, Alper

2012-04-01

232

[Establishment of a complete daily time series of precipitation and its change characteristics in forest region of eastern China during 1961-2010].  

PubMed

To accurately interpolate the missing precipitation data from meteorological observation stations within a region to obtain a complete precipitation series is of significance in improving the spatial and temporal resolution in analyzing the effects of climate change. By using spatial correlation and stepwise regression techniques, this paper interpolated the missing precipitation data for an individual day or less than 7 days in a month from the 853 meteorological stations in the forest region of Eastern China in 1961-2010, as a consequent establishment of the complete time series precipitation datasets of the observation stations in 1961-2010 established. Based on these, trend analysis approach was applied to analyze the variation characteristics of the annual precipitation, annual precipitation days, and extreme precipitation events in the region in 1961-2010. During the study period, the annual precipitation in the region presented an insignificant increasing trend, with a tendency of 5.58 mm (10 a) -1, but the decadal variation was obvious. The annual precipitation days reduced significantly, while the annual extreme precipitation days and extreme precipitation volumes increased significantly, with a tendency of 0.12 d (10 a) -1 and 10. 22 mm (10 a)-1, respectively. Since the 1990s, the extreme precipitation events became frequently and intensively, and the proportion of the volumes of extreme precipitation to total precipitation increased significantly. Both the extreme precipitation days and the volumes of extreme precipitation had an abrupt change in 1993. PMID:23898664

Chi, Ya-fei; Zhang, Cheng-yi; Liang, Cun-zhu; Hong, Wu

2013-04-01

233

The relationship between biological cognitive and psychosocial characteristics of parents and the weight of infant at the time of birth in Isfahan  

PubMed Central

Introduction: The present study was connected in order to evaluate the relationship between biological, cognitive and psychosocial characteristics of mothers and the weight of infant at the time of birth. Materials and Methods: In order to conduct this research a sample of 910 women among recently delivered mothers of Isfahan province in 2009 were selected. From stratified sampling and cluster sampling according to the percentage of population in each of the cities of Isfahan Province was used. The data was gathered with a questionnaire prepared by the researcher in order to evaluate the biological cognitive and psychosocial characteristics of mothers, in addition to the Enrich marital satisfaction test. After collecting data, the analysis of the data was done with SPSS software in two categories of descriptive and inferential statistics by using logistic regression model. Results: The results showed that the prevalence of low weight infants was 9.5 percent and 38.7 percent of pregnancies was unwanted. Twenty-nine percent of mothers had marital dissatisfaction. 15/6 percent of pregnancies were below 20 years old and 22 percent was above of 35 years old. 38.9 percent of mothers were exposed to cigarette smoke. The average of weight gain during pregnancies was 9 kilograms. Thirty three percent of mothers had high blood pressure during pregnancy, 26.7 percent had history of abortion and 31.9 percent had history of bleeding. 23/1percent of women was employed during pregnancy, 19.8 percent gave twin birth and 21/1 percent of parents were relative of each other, 29.7 percent of deliveries were done in cesarean way. Conclusion: The results of this study showed that severe marital dissatisfaction, abnormal blood pressure during pregnancy, being employed during pregnancy, weight gain less than 5 Kg during pregnancy, pregnancy below the age of 20 can meaning fully increase the possibility of low birth weight in infant (?=0.05). The results were consisting with the previous findings and indicated that some of the applicable benefits of this research can be recording of information about each delivery in the whole country with holding training workshops of before and during pregnancy skills by welfare organization. PMID:24251279

Talebian, Mohammad Hassan; Afrooz, Gholam Ali; Hooman, Heidar Ali; Aghaei, Asghar

2013-01-01

234

A rock magnetism study of the Shepody Fm. from the Maritime Provinces of Canada. Better constrained inclination corrections and timing of characteristic remanence acquisition in red beds.  

NASA Astrophysics Data System (ADS)

An inclination correction had previously been applied by isolating the characteristic remanence (ChRM) using both thermal and chemical demagnetization and by measuring the anisotropy of magnetic susceptibility (AMS) of the characteristic remanence carrying grains isolated through chemical demagnetization. The individual particle anisotropy was estimated by evaluating the azimuthal uniformity of the corrected directions, as calculated by Mu [Fisher et al., 1987; Tauxe, 1993]. The mean corrected direction yielded a corrected paleopole at 27.8° N, 117.8° E, A95= 6.6°. When combined with other lower Carboniferous paleopoles from North America corrected for inclination shallowing, a mean pole position lies at 27.9° N, 114.9° E, N= 4, with an A95= 4.6°, showing a large decrease in scatter when compared to the uncorrected mean paleopole which lies at 39° N, 295.9° E, N= 4, and has an A95= 12°. Because the individual particle anisotropy of hematite is difficult to determine experimentally, anisotropy of partial thermal remanence magnetization (pTRM), and anisotropy of high field isothermal remanence magnetization (hf-IRM) experiments have been performed. Hf-IRM experiments proved extremely successful and comparable to the AMS data, and led to identical inclination corrections. However, detailed analyses of IRM acquisition curves using the expectation- maximization algorithm [Heslop et al., 2002] have been performed in order to constrain the magnetic mineralogies contributing to the remanence. Results indicate that magnetite is more important than previously estimated, contributing 10%- 20% of the remanence. The anisotropy of the magnetite may have contaminated the total anisotropy previously measured for the samples and assumed to be entirely due to hematite, therefore affecting the inclination correction. In order to resolve the contribution of magnetite to the anisotropy, the magnetization components carried by hematite and magnetite have been separated on the basis of the distinct linear trends in thermal demagnetization demagnetograms. The two populations appear to share a common mean at the 95% confidence limit [McFadden and Lowes, 1981]. Relative anisotropies will be measured by AAR for magnetite, and hf-IRM followed by AF demagnetization and heating up to 120°C for hematite, in order to eliminate the contributions of magnetite and goethite, respectively. This will allow independent inclination corrections to be applied. Results of a comparison of means test applied after correction will further corroborate the validity of the inclination correction and help constrain the relative timing of acquisition of the magnetite and hematite remanences.

Bilardello, D.; Kodama, K. P.

2006-05-01

235

Determination of time-of-travel, dispersion characteristics, and oxygen reaeration coefficients during low streamflows--Lower Tacony/Frankford Creek, Philadelphia, Pennsylvania  

USGS Publications Warehouse

Time-of-travel, dispersion characteristics, and oxygen reaeration coefficients were determined by use of dye and gas tracing for a 2-mile reach of Tacony/Frankford Creek in Philadelphia, southeastern Pennsylvania. The reach frequently has concentrations of dissolved oxygen (DO) below the water-quality standard of 4 milligrams per liter during warm months. Several large combined sewer overflows (CSOs), including one of the largest in Philadelphia (former Wingohocking Creek), discharge to the study reach in this urbanized watershed, affecting water quality and the timing and magnitude of storm peaks. In addition, a dam that commonly results in backwater conditions and reduced natural reaeration is present a few hundred feet from the end of the study reach. Time-of-travel and reaeration data were collected under base-flow conditions in August and September 2009 for three sub-reaches from Roosevelt Boulevard (U.S. Route 1) to Castor Avenue. Determination of traveltimes to the centroid of the dye cloud were needed for calculation of the reaeration coefficients. Results of the dye study in Tacony/Frankford Creek indicate that traveltimes were affected by the presence of man-made structures, such as the large scour hole and pool developed at the outfall of the T14 CSO and the dam, both of which reduce stream velocities. Mean stream velocities during the dye-tracer tests ranged from a maximum of 0.44 to 0.04 foot per second through a large pool. The dispersion efficiency of the stream was determined from relations between normalized unit concentrations to time to peak for use in water-quality modeling. Oxygen reaeration coefficients determined by a constant rate-injection method using propane as the tracer gas were as low as 0.04 unit per hour in a long pool affected by backwater conditions behind a dam. The highest reaeration coefficient was 2.29 units per hour for a steep-gradient reach with multiple winding channels through gravel deposits, just downstream of a large scour pool developed at the outlet of the T14 CSO. Reaeration coefficients determined from the field tracer-gas method were compared to values calculated by two other methods, one that is based on theoretical equations using physical properties of the stream as variables and the other that is based on equations using the timing of measured daily maximum DO concentrations in the stream. Reaeration coefficients from the two alternate methods were most similar to values determined from the field tracer-gas method for the upstream portion of the study reach, characterized by free-flowing riffle and pools. Values of reaeration coefficients determined by the tracer-gas method were 2 to 10 times higher than values determined by 2 alternate methods for most subreaches hydraulically affected by man-made structures. In addition to the tracer gas, propane, the gas analysis also included methane, ethane, and ethene, of which only methane was measured in concentrations above a few micrograms per liter. Methane, thought to occur naturally or because of ongoing processes in the stream, was measured in concentrations ranging from 6.6 to 78 micrograms per liter; the concentrations were greatest in sub-reaches dominated by pools.

Senior, Lisa A.; Gyves, Matthew C.

2010-01-01

236

Influence of ethanol blends on the combustion performance and exhaust emission characteristics of a four-cylinder diesel engine at various engine loads and injection timings  

Microsoft Academic Search

The aim of this work is to investigate the effect of ethanol blending to diesel fuel on the combustion and exhaust emission characteristics of a four-cylinder diesel engine with a common-rail injection system. The overall spray characteristics, such as the spray tip penetration and the spray cone angle, were studied with respect to the ethanol blending ratio. A spray visualization

Su Han Park; In Mo Youn; Chang Sik Lee

2011-01-01

237

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

238

Flow Structure and Mass Transfer Investigation of the Turbulized Boundary Layer with Ethanol Evaporation and Diffusion Combustion  

Microsoft Academic Search

Uncertainty of evaluation of each factor (separation laminar-turbulent transition combustion and turbulization) hinders mathematical simulation of the joint effect on gas dynamic and thermal characteristics of the boundary layer. The characteristics may be most reliably determined experimentally. The work objective is the experimental study of the boundary layer structure comparison of the fields of temperature velocity and its pulsation with

E. P. Volchkov; B. F. Boyarshinov; V. I. Titkov

2002-01-01

239

Winter 2013 Time Time Time Time Time  

E-print Network

11/8/2012 Winter 2013 Time Time Time Time Time Ugrad Grad Section Lab 590 Ugrad Grad Section Lab/143 quiz sections offered multiple times Thurs. (142) and T/Th (143) Grad courses TBD: 599v1, 517 548 517

Borenstein, Elhanan

240

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

241

Effect of Time of Initiation of Feeding after Hatching and Influence of Dietary Ascorbic Acid Supplementation on Productivity, Mortality and Carcass Characteristics of Ross 308 Broiler Chickens in South Africa  

Microsoft Academic Search

An experiment was conducted to evaluate the effect of time of initiation of feeding after hatching and influence of dietary ascorbic supplementation during realimentation on productivity, carcass characteristics and mortality of Ross 308 broiler chickens. The study was a factorial arrangement in a complete randomized design. Six hundred and seventy five unsexed Ross 308 broiler chickens with an initial weight

C. A. Mbajiorgu; D. Norris

2007-01-01

242

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

243

Effects of structure parameters on time response and power-current characteristics of InGaN\\/GaN single quantum well laser by solving rate equations  

Microsoft Academic Search

There are several equation sets that are used to characterize of the performance parameters of a quantum well (QW) lasers. One of simple and important equations groups which are used to study of laser characteristics in the almost powerful and expensive simulation tools such as Crosslight, ISE TCAD and SILVACO is of rate equations. A numerical analysis of rate equations

Ghasem Alahyarizadeh; Hassan Aghajani; Hadi Mahmodi; Raheleh Rahmani; Zainuriah Hassan

2012-01-01

244

Flow visualization on helicopter blades using acenaphthen  

Microsoft Academic Search

Results of visualization of boundary layer characteristics on a helicopter blade under practical conditions are described. The acenaphthene visualization method was used. It was found to be effective in ascertaining the laminar turbulent transition point. The results confirm the design philosophy of generating the longest possible laminar paths in order to minimize skin friction drag. Despite some inadequacy of surface

Claas-Hinrik Rohardt

1992-01-01

245

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

246

The Influence of Temperature-Time Parameter of Welded Joints Thermal Treatment on Strength-Related Characteristics of Chromium-Molybdenum and Low-Alloy Manganese Steels  

Microsoft Academic Search

The article deals with the analysis of the dependence of strength-related characteristics of welded joints from chromium-molybdenum steel (ASTM A335 Grd. P5) and low-alloy manganese steel (S355J2G3 EN10025-2) upon the parameters of heat treatment. Steel mechanical properties after post-weld heat treatment were analyzed. Chromium- molybdenum (Cr - 5 %) steel and structural low-alloy manganese steel (Mn - 1.4 %) was

Algirdas Vaclovas VALIULIS

2007-01-01

247

A time dependent difference theory for sound propagation in ducts with flow. [characteristic of inlet and exhaust ducts of turbofan engines  

NASA Technical Reports Server (NTRS)

A time dependent numerical solution of the linearized continuity and momentum equation was developed for sound propagation in a two dimensional straight hard or soft wall duct with a sheared mean flow. The time dependent governing acoustic difference equations and boundary conditions were developed along with a numerical determination of the maximum stable time increments. A harmonic noise source radiating into a quiescent duct was analyzed. This explicit iteration method then calculated stepwise in real time to obtain the transient as well as the steady state solution of the acoustic field. Example calculations were presented for sound propagation in hard and soft wall ducts, with no flow and plug flow. Although the problem with sheared flow was formulated and programmed, sample calculations were not examined. The time dependent finite difference analysis was found to be superior to the steady state finite difference and finite element techniques because of shorter solution times and the elimination of large matrix storage requirements.

Baumeister, K. J.

1979-01-01

248

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

249

Characteristic 0 Characteristic p > 0  

E-print Network

Kowalski Instytut Matematyczny Uniwersytetu Wroclawskiego May 22, 2010 Kowalski Transcendence in positive Algebraic independence Kowalski Transcendence in positive characteristic #12;Set-up Characteristic 0 independent modulo C, then trdegC (x, y) n + 1. Kowalski Transcendence in positive characteristic #12;Set

Kowalski, Piotr

250

Regional characteristics, timing, and significance of dissolution and collapse features in Lower Cretaceous carbonate platform strata, Desoto Canyon area, offshore Alabama-Florida  

E-print Network

zones is only found above the Coniacian-Santonian unconformity. These relationships suggest a regional confined freshwater aquifer system developed within the Lower Cretaceous interval at about Coniacian-Santonian time when meteoric groundwater likely...

Iannello, Christine

2012-06-07

251

[Obstructive sleep apnea syndrome in patients with acute myocardial infarction: timing of onset of the disease, clinico-functional and some other characteristics].  

PubMed

With the aim of elucidating special features of the course of acute myocardial infarction (MI) in patients with obstructive sleep apnea syndrome (OSA) we retrospectively studied clinico-functional parameters of 476 patients including 64 (13.3%) who had episodes of apnea during sleep. Frequency of OSA was 1.3 times greater in overweight patients, and 2.3 times greater in those with history of diabetes mellitus. Development of MIs in patients with OSA more often occurred during night or early morning (relative risk 6.00-7.41) and depended on the severity of OSA. Patients with MI and OSA had lowering of blood levels of high density lipoproteins, elevation of levels of triglycerides and high sensitive C-reactive protein. We noted the role of excessive neurohumoral activity in these processes. A conclusion was made about necessity of timely diagnosis of OSA during MI and timely correction of the revealed pathophysiological traits. PMID:23548424

Ivanov, A P; Rostorotskaia, V V; Kliukvin, D V; Él'gardt, I A

2013-01-01

252

Determination of the time delay in the case of two-path propagation on the basis of the attenuation characteristics for two adjacent frequencies  

NASA Technical Reports Server (NTRS)

Pronounced fading occurring in the line of sight radio links at frequencies below 10 GHz can be traced to the effects of multipath propagation. Modulation disturbances depend on travel time differences between the direct wave and the wave which is reflected at atmospheric layers. A method described for the determination of the time delay is based on an indirect approach which utilizes the difference in fading at various frequencies. The method was employed in measurements involving a distance of 181 km. The results obtained in the measurement are discussed.

Gilroi, H. G.

1979-01-01

253

Comparison of sludge characteristics and performance of a submerged membrane bioreactor and an activated sludge process at high solids retention time  

Microsoft Academic Search

This work aims to compare biomass structure and performance of a submerged membrane bioreactor (SMBR) and an activated sludge process (ASP) treating the same domestic wastewater. The influence of the separation technique (membrane filtration or settling) and operation at high sludge-retention time (SRT) were investigated. Over the entire range of SRT (10–110 days), the SMBR achieved very good organic removal

Anthony Massé; Mathieu Spérandio; Corinne Cabassud

2006-01-01

254

The contribution of time series analysis to the study of the hydrodynamic characteristics of the karst systems: Application on two typical karst aquifers of Greece (Trifilia, Almyros Crete)  

Microsoft Academic Search

Time series analysis was applied to the precipitation, spring discharge and piezometric head data of two representative karst systems of Greece in order to study the function, hydrodynamic behaviour and hydraulic properties of the aquifers. Results obtained through autocorrelation, spectral density, cross-correlation, cross-amplitude, gain, coherence and phase functions showed that the Trifilia karst system is slightly karstified and has a

George Panagopoulos; Nicolaos Lambrakis

2006-01-01

255

Individual personality-related characteristics of event-related EEG potentials recorded in an experimental situation requiring production of time intervals  

Microsoft Academic Search

Event-related EEG potentials (ERP) were recorded from 75 tested adult men and women; recording was performed from C3 and C4\\u000a points. The experimental situation required internal counting of time intervals limited by two pushes of a button. The experimental\\u000a paradigm provided a substantial level of uncertainty, and a high level of attention needed to be maintained. The tested subjects\\u000a were

V. B. Pavlenko; I. N. Konareva

2000-01-01

256

Electrical interface characteristics (IV), optical time of flight measurements, and the x-ray (20 keV) signal response of amorphous-selenium\\/crystalline-silicon heterojunction structures  

Microsoft Academic Search

We have investigated the dark current, optical TOF (time of flight) properties, and the X-ray response of amorphousselenium (a-Se)\\/crystalline-silicon (c-Si) heterostructures for application in digital radiography. The structures have been studied to determine if an x-ray generated electron signal, created in an a-Se layer, could be directly transferred to a c-Si based readout device such as a back-thinned CCD (charge

David M. Hunter; Chu An Ho; George Belev; Giovanni de Crescenzo; Safa O. Kasap; Martin J. Yaffe

2011-01-01

257

Coupled porous-medium and free flow under turbulent and rough conditions  

E-print Network

Euler one matrix Preliminary Results Wind Tunnel Evaporation Experiments experiment laminar turbulent evaporationrate[mm/d] time [d] stage 1 stage 2 Analysis Cooperations wind tunnel experiments: CESEP, Colorado for CFD. DCW Industries, La Ca�ada, California, 2. edition. Simulations are performed using the open

Cirpka, Olaf Arie

258

The Effect of Spacing and Time of Thinning on the Yield, Growth, and Fruiting Characteristics of the Cotton Plant in 1925.  

E-print Network

which Cook (19) now calls "single-stalk cotton culture,)' he states: "By talting account of the specializecl habits of branching, it is possible to esercise a much more effective coiitrol of the clereloprnent of the plants, so as to secure earlier... work was undertaken to obtain more evidence as to the effect of time of thinning on cotton plants spaced the same distance apart in the row in relation to vegetative growth and fruiting charac- teristics, as well as to the yield. Accordingly, a study...

Stansel, R. H. (Roy Harrison)

1927-01-01

259

Space-time characteristics of fragment emission in the {ital E}/{ital A}=30 MeV {sup 129}Xe+{sup nat}Cu reaction  

SciTech Connect

Intermediate-mass-fragment emission has been studied in central {ital E}/{ital A}=30 MeV {sup 129}Xe+{sup nat}Cu reactions. The measured fragment multiplicities, reduced-velocity correlation functions, and emission velocities have been compared with schematic three-body trajectory calculations and with three statistical models with input based upon a dynamical BNV code. The statistical models which include expansion either explicitly or implicitly are able to generate a sufficient number of fragments. The three-body trajectory calculations indicate a mean emission time of {approx}200 fm/{ital c}, consistent with sequential decay. Dynamical expanding-emitting source calculations predict a similar time scale for fragment emission and give satisfactory agreement with the experimental correlation functions if the experimental angular distributions are incorporated into the model. The Berlin multifragmentation model gives good agreement with the experimental charge distributions, and, depending upon the choice of radius parameter, can provide agreement with either the correlation functions or the fragment emission velocities, but not with both simultaneously. Although an overall good agreement is obtained in the statistical model comparisons, even in the most violent collisions the angular distributions and fragment emission velocities are incompatible with completely equilibrated decay from a single source.

Bowman, D.R.; Colonna, N.; Friedman, W.A.; Celano, L.; D`Agostino, M.; Dinius, J.D.; Ferrero, A.; Gelbke, C.K.; Glasmacher, T.; Handzy, D.O.; Horn, D.; Hsi, W.C.; Huang, M.; Iori, I.; Lisa, M.A.; Lynch, W.G.; Margagliotti, G.V.; Milazzo, P.M.; Montoya, C.P.; Moroni, A.; Peaslee, G.F.; Phair, L.; Petruzzelli, F.; Scardaoni, R.; Schwarz, C.; Tsang, M.B.; Williams, C. [Atomic Energy of Canada, Ltd., Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada)] [Atomic Energy of Canada, Ltd., Chalk River Laboratories, Chalk River, Ontario, K0J 1J0 (Canada); [INFN, Via Amendola 173, 70126 Bari (Italy); [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); [Dipartimento di Fisica and INFN, Via Irnerio 46, 40126 Bologna (Italy); [NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); [Dipartimento di Fisica and INFN, Via Celoria 12, 20133 Milano (Italy); [Dipartimento di Fisica and INFN, Via A. Valerio 2, 34127 Trieste (Italy)

1995-08-01

260

Influence of soil properties and climate characteristics on transpirable soil water for two varieties with differences in their crop cycle timing  

NASA Astrophysics Data System (ADS)

This paper presents an analysis of soil water content in two vineyards planted with Chardonnay and Cabernet Sauvignon in the Penedès Designation of Origin (DO). Climate is Mediterranean with maritime influence. The main soil types are Typic Xerorthent and Fluventic Haploxerept and soil is bare most of the time to avoid the competition of weeds for water. The plantation pattern was uniform in both cultivars, 1.3*3m. Soil moisture was analysed at each area from 10 to 90 cm every 20 cm, using TDF probes during two crop growing cycles (2010-2012). Soil water balance for years with different rainfall amount and distribution throughout the year was simulated using the Soil and Water Assessment Tool (SWAT). Differences in phenology of about one month existed among both varieties. In addition, the soil hydrological properties variability, resulted from land levelling operations before vineyard establishment, affects crop's soil water availability. These two facts made that, under the same rainfall amount and distribution, water available during the crop cycle were different for both varieties. The transpirable soil water fraction reached very low values, close to 0.1, particularly in the variety with early phenology timing. This pattern was repeated in different years depending on rainfall distribution, which affected grape production with significant yield reductions (up to 38% in relation to the average were found in some years).

Ramos, Maria C.

2014-05-01

261

Embedded Protostars in the Dust, Ice, and Gas In Time (DIGIT) Herschel Key Program: Continuum SEDs, and an Inventory of Characteristic Far-infrared Lines from PACS Spectroscopy  

NASA Astrophysics Data System (ADS)

We present 50-210 ?m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 ?m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H2O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 ? 13 up to J = 40 ? 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 ?m [O I] flux ratio is 17.2 ± 9.2. The [O I] 63 ?m line correlates with L bol, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L bol increased by 1.25 (1.06) and T bol decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ({\\langle { {N}}\\rangle} = (0.70 +/- 1.12){{} \\times 10^{49}} total particles). { {N}}_CO correlates strongly with L bol, but neither T rot nor { {N}}_CO(warm)/{ {N}}_CO(hot) correlates with L bol, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H2O ({\\langle {T_rot}\\rangle } = 194 +/- 85 K) and OH ({\\langle {T_rot}\\rangle } =183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Green, Joel D.; Evans, Neal J., II; Jørgensen, Jes K.; Herczeg, Gregory J.; Kristensen, Lars E.; Lee, Jeong-Eun; Dionatos, Odysseas; Yildiz, Umut A.; Salyk, Colette; Meeus, Gwendolyn; Bouwman, Jeroen; Visser, Ruud; Bergin, Edwin A.; van Dishoeck, Ewine F.; Rascati, Michelle R.; Karska, Agata; van Kempen, Tim A.; Dunham, Michael M.; Lindberg, Johan E.; Fedele, Davide; DIGIT Team

2013-06-01

262

EMBEDDED PROTOSTARS IN THE DUST, ICE, AND GAS IN TIME (DIGIT) HERSCHEL KEY PROGRAM: CONTINUUM SEDs, AND AN INVENTORY OF CHARACTERISTIC FAR-INFRARED LINES FROM PACS SPECTROSCOPY  

SciTech Connect

We present 50-210 {mu}m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 {mu}m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H{sub 2}O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 {yields} 13 up to J = 40 {yields} 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 {mu}m [O I] flux ratio is 17.2 {+-} 9.2. The [O I] 63 {mu}m line correlates with L{sub bol}, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L{sub bol} increased by 1.25 (1.06) and T{sub bol} decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ( = (0.70 {+-} 1.12) x 10{sup 49} total particles). N{sub CO} correlates strongly with L{sub bol}, but neither T{sub rot} nor N{sub CO}(warm)/N{sub CO}(hot) correlates with L{sub bol}, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H{sub 2}O ( = 194 +/- 85 K) and OH ( = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines.

Green, Joel D.; Evans, Neal J. II; Rascati, Michelle R. [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Jorgensen, Jes K.; Dionatos, Odysseas; Lindberg, Johan E. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Kristensen, Lars E.; Yildiz, Umut A.; Van Kempen, Tim A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Salyk, Colette [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Meeus, Gwendolyn [Dpt. Fisica Teorica, Universidad Autonoma de Madrid, Campus Cantoblanco, E-28049 Madrid (Spain); Bouwman, Jeroen [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Visser, Ruud; Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Van Dishoeck, Ewine F.; Karska, Agata; Fedele, Davide [Max-Planck Institute for Extraterrestrial Physics, Postfach 1312, D-85741 Garching (Germany); Dunham, Michael M., E-mail: joel@astro.as.utexas.edu [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Collaboration: DIGIT Team1

2013-06-20

263

Effect of very fast chilling and aging time on ultra-structure and meat quality characteristics of Chinese Yellow cattle M. Longissimus lumborum.  

PubMed

Objectives of the current study were to evaluate meat ultra-structure and tenderness variation at different chilling regimes and aging times. Hot boned longissimus lumborum of 18 Chinese crossbred cattle were divided into 4 portions per side. One portion underwent very fast chilling (VFC, at -21 °C to achieve core temperature of 0 °C, then transferred to another incubator at 2 °C), whereas other treatments were held at 14, 7 and 0 °C for 10 h postmortem, respectively. At 10 h postmortem, all muscles were vacuum aged at 2 °C for 21 d. Cold shortened muscles had greatest absolute amount of tenderization during aging. VFC caused lowest sarcomere length, with super-contractions, ruptured Z-lines and myofibril cleavage, but improved myofibril fragmentation index (MFI), with no significant negative effect on toughness. Overall, aging improved the meat quality of cold shortened beef. Moreover, it should be prudent in some applications to apply VFC to excised muscles from a food safety perspective, and to improve tenderness compared to cold-shortened muscles. PMID:22857853

Li, Ke; Zhang, Yimin; Mao, Yanwei; Cornforth, Daren; Dong, Pengcheng; Wang, Renhuan; Zhu, He; Luo, Xin

2012-12-01

264

Effects of water vapor pretreatment time and reaction temperature on CO(2) capture characteristics of a sodium-based solid sorbent in a bubbling fluidized-bed reactor.  

PubMed

CO(2) capture from flue gas using a sodium-based solid sorbent was investigated in a bubbling fluidized-bed reactor. Carbonation and regeneration temperature on CO(2) removal was determined. The extent of the chemical reactivity after carbonation or regeneration was characterized via (13)C NMR. In addition, the physical properties of the sorbent such as pore size, pore volume, and surface area after carbonation or regeneration were measured by gas adsorption method (BET). With water vapor pretreatment, near complete CO(2) removal was initially achieved and maintained for about 1-2min at 50 degrees C with 2s gas residence time, while without proper water vapor pretreatment CO(2) removal abruptly decreased from the beginning. Carbonation was effective at the lower temperature over the 50-70 degrees C temperature range, while regeneration more effective at the higher temperature over the 135-300 degrees C temperature range. To maintain the initial 90% CO(2) removal, it would be necessary to keep the regeneration temperature higher than about 135 degrees C. The results obtained in this study can be used as basic data for designing and operating a large scale CO(2) capture process with two fluidized-bed reactors. PMID:17604081

Seo, Yongwon; Jo, Sung-Ho; Ryu, Chong Kul; Yi, Chang-Keun

2007-10-01

265

Patient characteristics that influence efficacy of prophylaxis with rFVIII-FS three times per week: a subgroup analysis of the LIPLONG study.  

PubMed

Prospective data on the efficacy of secondary prophylaxis in adults with haemophilia A are limited. To analyse bleeding outcomes in the sucrose-formulated recombinant factor VIII [rFVIII-FS (control)] arm of the LIPLONG study, a randomized, double-blind, 52-week trial was conducted in patients with severe haemophilia A receiving prophylaxis with the investigational product BAY 79-4980 or rFVIII-FS. The per-protocol population of previously treated patients with severe haemophilia A without a history of inhibitors (n = 68 males; mean age, 34.4 years) received 25 IU kg?1 rFVIII-FS three times per week for a median of 50.7 weeks. Annualized bleeding rates were assessed and analysed according to predefined target joint status at study start, prestudy treatment type (prophylaxis vs. on demand), age (<30 or ?30 years), geographical region, bleeding frequency during the previous 6 months and physical activity status during the study using the Student t-test. The annualized median (range) number of bleeds was 2.2 (0.0–23) bleeds per year. The median (range) number of bleeds per year was significantly lower in patient subgroups without vs. with target joints [0.5 (0.0–17.1) vs. 4.2 (0.0–22.8); P = 0.02] and in those with ?9 vs. >9 bleeds during the previous 6 months [1.1 (0.0–19.2) vs. 5.3 (0.0–22.8); P = 0.01]. Following randomization to prophylaxis with rFVIII-FS, bleeding frequency was effectively reduced. Absence of target joints and prestudy bleeding frequency were predictors of a low bleeding frequency during prophylaxis treatment. PMID:24847524

Lalezari, S; Coppola, A; Lin, J; Enriquez, M M; Tseneklidou-Stoeter, D; Powell, J; Ingerslev, J

2014-05-01

266

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

267

Individual, family and offence characteristics of high risk childhood offenders: comparing non-offending, one-time offending and re-offending Dutch-Moroccan migrant children in the Netherlands  

PubMed Central

Background Childhood offenders are at an increased risk for developing mental health, social and educational problems later in life. An early onset of offending is a strong predictor for future persistent offending. Childhood offenders from ethnic minority groups are a vulnerable at-risk group. However, up until now, no studies have focused on them. Aims To investigate which risk factors are associated with (re-)offending of childhood offenders from an ethnic minority. Method Dutch-Moroccan boys, who were registered by the police in the year 2006-2007, and their parents as well as a control group (n = 40) were interviewed regarding their individual and family characteristics. Two years later a follow-up analysis of police data was conducted to identify one-time offenders (n = 65) and re-offenders (n = 35). Results All groups, including the controls, showed substantial problems. Single parenthood (OR 6.0) and financial problems (OR 3.9) distinguished one-time offenders from controls. Reading problems (OR 3.8), having an older brother (OR 5.5) and a parent having Dutch friends (OR 4.3) distinguished re-offenders from one-time offenders. First offence characteristics were not predictive for re-offending. The control group reported high levels of emotional problems (33.3%). Parents reported not needing help for their children but half of the re-offender's families were known to the Child Welfare Agency, mostly in a juridical framework. Conclusion The Moroccan subgroup of childhood offenders has substantial problems that might hamper healthy development. Interventions should focus on reaching these families tailored to their needs and expectations using a multi-system approach. PMID:22014276

2011-01-01

268

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

269

Seasonal characteristics of fine particulate matter (PM) based on high resolution time-of-flight aerosol mass spectrometric (HR-ToF-AMS) measurements at the HKUST Supersite in Hong Kong  

NASA Astrophysics Data System (ADS)

Atmospheric particulate matter (PM) remains poorly understood due to the lack of comprehensive measurements at high time resolution for tracking its dynamic features and the lack of long-term observation for tracking its seasonal variability. Here, we present highly time-resolved and seasonal compositions and characteristics of non-refractory components in PM with diameter less than 1 ?m (NR-PM1) at a suburban site in Hong Kong. The measurements were made with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) at the Hong Kong University of Science and Technology (HKUST) Air Quality Research Supersite for four months, with one in each season of the year. The average NR-PM1 concentration of ~15 ?g m-3 is higher than those AMS measurements made in South Korea and Japan, but lower than those in North China, the Yangtze River Delta and the nearby Pearl River Delta. The seasonal dependence of the total NR-PM1 monthly averaged concentrations was small but that of the fractions of the species in NR-PM1 was significant. Site characteristic plays an important role in the relative fractions of species in NR-PM1 and our results are generally consistent with measurements at other non-urban sites in this regard. Detailed analyses were conducted on the AMS data in the aspects of (1) species concentrations, (2) size distributions, (3) degree of oxygenation of organics, and (4) positive matrix factorization (PMF)-resolved organic factors in a seasonal context, as well as with air mass origin from back-trajectory analysis. Sulfate had the highest fraction in NR-PM1 (> 40%) and the surrogates of secondary organic species, semi-volatile oxygenated organic aerosol (SVOOA) and low-volatility oxygenated organic aerosol (LVOOA), prevailed (~80%) in the organic portion of NR-PM1. Local contributions to the organic portion of NR-PM1 at this suburban site was strongly dependent on season. The hydrocarbon-like organic aerosol (HOA) factor related to local traffic emissions contributed > 10% to organic aerosols in spring and summer, but only 6-7% in autumn and winter. The cooking organic aerosol (COA) factor contributed > 10% to organic aerosols in winter. With the aid of highly time-resolved data, diurnal patterns of the degree of oxygenation of organic aerosols were used to determine the sources and formation processes of the least understood organic portion of PM. The oxygen-to-carbon atomic ratio (O : C) and average carbon oxidation state (OSC) showed little variation in autumn and winter when the long-range transport of oxidized organics dominated, whereas they peaked in the afternoon in spring and summer when locally produced secondary organic aerosol prevailed. Air mass origin, in contrast, had a strong influence on both NR-PM1 concentrations and the fractions of species in NR-PM1. The findings of the current study provide a better understanding of the role of air mass origin in the seasonal characteristics of the PM composition and the relative importance of local vs. transported organic aerosols in this region.

Li, Y. J.; Lee, B. P.; Su, L.; Fung, J. C. H.; Chan, C. K.

2014-08-01

270

Flow Structure and Mass Transfer Investigation of the Turbulized Boundary Layer with Ethanol Evaporation and Diffusion Combustion  

NASA Astrophysics Data System (ADS)

Uncertainty of evaluation of each factor (separation laminar-turbulent transition combustion and turbulization) hinders mathematical simulation of the joint effect on gas dynamic and thermal characteristics of the boundary layer. The characteristics may be most reliably determined experimentally. The work objective is the experimental study of the boundary layer structure comparison of the fields of temperature velocity and its pulsation with data on heat and mass transfer.

Volchkov, E. P.; Boyarshinov, B. F.; Titkov, V. I.

2002-07-01

271

Geologic Time  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses the characteristics of geologic time, including the law of superposition, fossil preservation, casts and molds, and various events through the history of the Earth. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

272

Bayesian estimation of test characteristics of real-time PCR, bacteriological culture and California mastitis test for diagnosis of intramammary infections with Staphylococcus aureus in dairy cattle at routine milk recordings.  

PubMed

Danish farmers can order a real-time PCR mastitis diagnostic test on routinely taken cow-level samples from milk recordings. Validation of its performance in comparison to conventional mastitis diagnostics under field conditions is essential for efficient control of intramammary infections (IMI) with Staphylococcus aureus (S. aureus). Therefore, the objective of this study was to estimate the sensitivity (Se) and specificity (Sp) of real-time PCR, bacterial culture (BC) and California mastitis test (CMT) for the diagnosis of the naturally occurring IMI with S. aureus in routinely collected milk samples using latent class analysis (LCA) to avoid the assumption of a perfect reference test. Using systematic random sampling, a total of 609 lactating dairy cows were selected from 6 dairy herds with bulk tank milk PCR cycle threshold (Ct) value ?39 for S. aureus. At routine milk recordings, automatically obtained cow-level (composite) milk samples were analyzed by PCR and at the same milking, 2436 quarter milk samples were collected aseptically for BC and CMT. Results showed that 140 cows (23%) were positive for S. aureus IMI by BC while 170 cows (28%) were positive by PCR. Estimates of Se and Sp for PCR were higher than test estimates of BC and CMT. SeCMT was higher than SeBC however, SpBC was higher than SpCMT. SePCR was 91%, while SeBC was 53%, and SeCMT was 61%. SpPCR was 99%, while SpBC was 89%, and SpCMT was 65%. In conclusion, PCR has a higher performance than the conventional diagnostic tests (BC and CMT) suggesting its usefulness as a routine test for accurate diagnosis of S. aureus IMI from dairy cows at routine milk recordings. The use of LCA provided estimates of the test characteristics for two currently diagnostic tests (BC, CMT) and a novel technique (real-time PCR) for diagnosing S. aureus IMI under field conditions at routine milk recordings in Denmark. PMID:23992955

Mahmmod, Yasser S; Toft, Nils; Katholm, Jørgen; Grønbæk, Carsten; Klaas, Ilka C

2013-11-01

273

Time Dependence Time Dependence  

E-print Network

Time Dependence 1/60 #12;Time Dependence deadline:= t + 5 2/60 #12;Time Dependence deadline:= t + 5 no problem 3/60 #12;Time Dependence deadline:= t + 5 no problem if t ;Time Dependence deadline:= t + 5 no problem if t Time

Hehner, Eric C.R.

274

Laser Microprobe Mass Spectrometry 1: Basic Principles and Performance Characteristics.  

ERIC Educational Resources Information Center

Describes the historical development, performance characteristics (sample requirements, analysis time, ionization characteristics, speciation capabilities, and figures of merit), and applications of laser microprobe mass spectrometry. (JN)

Denoyer, Eric; And Others

1982-01-01

275

ILLIAC 4 systems characteristics and programming manual  

NASA Technical Reports Server (NTRS)

The latest edition is presented of the Systems Characteristics and Programming Manual of the ILLIAC 4 array and parallel disc memory system. The major aspects of the array described include: the array systems characteristics, programming characteristics, definition and flow charts, and timing. A glossary of terms, and an instruction index are included.

1973-01-01

276

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

277

Characteristics of Outstanding Student Teachers  

ERIC Educational Resources Information Center

This paper describes the characteristics of student teachers who were evaluated as outstanding during their teacher education studies. Outstanding students were selected after 2 years of field experiences based on their teaching abilities and academic achievements. Data were collected at three points of time: before they commenced their studies at…

Eldar, Eitan; Talmor, Rachel

2006-01-01

278

Applicability of 2-D Time-Lapse High-Resolution Seismic Reflection Approach to Image Natural Salt-Dissolution and Subsidence in Central Kansas and Improved Post-Processed Vibroseis Data Characteristics  

E-print Network

The effectiveness of 2-D time-lapse imaging for monitoring natural dissolution of the Hutchinson Salt in eastern Reno County, Kansas was shown to be restricted when comparing high-resolution seismic reflection data acquired in 2008 with data...

Rice, Daniel

2009-01-12

279

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

280

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. PMID:23483841

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

2013-01-01

281

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

282

Telling Time  

NSDL National Science Digital Library

Lets practice telling time! Practice with the dragon to tell time. Dragon Telling Time How long does it take you to tell time?Stop the Clock! Can you set the correct time? Try it here! Setting the correct time ...

Berman, Ms.

2008-11-12

283

Observation of a metal-to-insulator transition with both Mott-Hubbard and Slater characteristics in Sr2IrO4 from time-resolved photocarrier dynamics  

E-print Network

We perform a time-resolved optical study of Sr[subscript 2]IrO[subscript 4] to understand the influence of magnetic ordering on the low energy electronic structure of a strongly spin-orbit coupled J[subscript eff] = 1/2 ...

Hsieh, David

284

Globally mapping baseflow characteristics  

NASA Astrophysics Data System (ADS)

Characterizing baseflow, the slowly varying portion of streamflow, is important for water resources management, hydropower generation, tracking contaminant transport, and other applications. Most previous studies of baseflow have analyzed small groups of catchments with similar characteristics. Now, to develop globally applicable models of baseflow characteristics, Beck et al. studied observations from 3394 catchments around the world with a variety of climatic, hydrological, and physiographic characteristics. Their novel approach investigates the relationship between catchment characteristics and baseflow characteristics, showing how baseflow is related to annual potential evaporation, mean snow water equivalent depth, abundance of surface water bodies, and other landscape characteristics. Their global maps of baseflow characteristics—which could be useful for benchmarking and calibrating hydrological models and for a variety of other hydrological applications—are freely available at http://www.hydrology-amsterdam.nl.

Balcerak, Ernie

2013-12-01

285

The Influence of Classroom Characteristics on High School Teacher Turnover  

Microsoft Academic Search

This paper examines the effect of class load and other factors on teacher turnover. Unlike previous studies, class load characteristics--class size, number of classes taught, and percentage of class time spent in areas outside a teacher's certification area--are included along with salary, personal characteristics, and district characteristics in a discrete time hazard model to simulate the effects of changing classroom

Daniel Mont; Daniel I. Rees

1996-01-01

286

Earthquake Characteristics and Earthquake-Explosion Discrimination.  

National Technical Information Service (NTIS)

Contents: Inversion of Travel-Time Data for Upper Mantle Structure; Determining Response Characteristics of Seismograph Systems; A Resolving Criterion for Band-Limited Filtration; Determination of Focal Depth and Focal Mechanism by Synthetic Seismograms; ...

C. Kisslinger, E. R. Engdahl, P. Luh, M. L. Smith, W. Gawthrop

1976-01-01

287

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  

Microsoft Academic Search

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 \\

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

2006-01-01

288

Telling Time  

NSDL National Science Digital Library

Practice telling time with these fun games and activities! Match the time on the clocks with this game! Match the clocks game! Primary Games Match the Clocks Tell time with a dragon. Stop the clock! Make the right time! Time to the Hour Quiz Time Test Time to the Minute Quiz Practice telling what time it will be later. Elapsed Time Work on Elapsed Time Test your skills with the Matching Elapsed Time Game ...

Lerdahl, Miss

2010-01-26

289

Starting Time Ending Time Starting Time  

E-print Network

Starting Time Ending Time Starting Time Name Of The Department/Unit Organizing The Event N How Would You Like Parking Arrangements Handled? Attendant Time (3 hour minimun): ) r e b m u N t n u-business hours. We may not be able to provide parking, depending on time of day and location. Consider public

Sjölander, Kimmen

290

Starting Time Ending Time Starting Time  

E-print Network

Starting Time Ending Time Starting Time Name Of The Department/Unit Organizing The Event N How Would You Like Parking Arrangements Handled? Attendant Time (3 hour minimun): Campus Department to schedule your event during non-business hours. We may not be able to provide parking, depending on time

Sjölander, Kimmen

291

Takeoff characteristics of turbofan engines  

Microsoft Academic Search

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

Young B. Suh

1990-01-01

292

Telling Time  

NSDL National Science Digital Library

Practice telling time with these fun games and activities! Match the time on the clocks with this game! Match the clocks game! Tell time with a dragon. Stop the clock! Practice telling what time it will be later. Elapsed Time ...

Fiefia, Mrs.

2010-03-23

293

Characteristic Evolution and Matching  

E-print Network

I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black spacetime. A prime application of characteristic evolution is to compute waveforms via Cauchy-characteristic matching, which is also reviewed.

Jeffrey Winicour

2005-08-23

294

Amplitude and correlation of environmental signals in solid precipitation, surface snow and deep ice core at Dome Fuji, Antarctica - Characteristics of climate and environmental signals with the various time scales -  

NASA Astrophysics Data System (ADS)

Two deep ice cores (DF1: 2503m, DF2: 3035m) at Dome Fuji, Antarctica have the in-depth information on 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+, Mg2+, Ca2+, dD, d18O, d-excess, dust. Generally, 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. Especially, warming events (AIM, inter-glacial stage) are studied with different time scale. Time scales of our studies are daily, yearly, decadal, few hundred and millennial-scales and glacial-interglacial cycle. Deep ice core records are compared with initial conditions (precipitation and surface snow). We show the difference of the chemistry of surface snow by the difference of the snow type in the same area. The amplitude of the variation of the signal becomes small from surface snow to ice. The average value of snow is inter-glacial stage level. By the way, the concentration of nitrate decreased from the snow surface as you know. Calcium and nitrate has no correlation in surface snow but they have a strong correlation in the ice core.

Motoyama, H.

2013-12-01

295

Characteristics of Successful Entrepreneurs.  

ERIC Educational Resources Information Center

Comparison of characteristics of 12 average and 12 superior small business people in three developing nations (India, Malawi, and Ecuador) found proactive qualities such as initiative and assertiveness, achievement orientation, and commitment to others characteristic of successful entrepreneurs. Other expected qualities (self-confidence,…

McClelland, David C.

1987-01-01

296

The wind characteristics program  

Microsoft Academic Search

Wind characteristics research activities emphasize wind resource assessment, site selection and evaluation techniques, and wind characteristics for wind turbine design, performance and operations evaluation. Wind resource analysis shows the greatest area of high wind power resource is in the midsection of the U.S. High wind power is available in other sections of the country and is described in some detail

L. L. Wendell

1981-01-01

297

ELM characteristics in MAST  

Microsoft Academic Search

Edge localized mode (ELM) characteristics in a large spherical tokamak (ST) with significant auxiliary heating are explored. High confinement is achieved in mega ampere spherical tokamak (MAST) at low ELM frequencies even though the ELMs exhibit many type III characteristics. These ELMs are associated with a reduction in the pedestal density but no significant change in the pedestal temperature or

A. Kirk; G. F. Counsell; H. R. Wilson; J.-W. Ahn; R. Akers; E. R. Arends; J. Dowling; R. Martin; H. Meyer; M. Hole; M. Price; P. B. Snyder; D. Taylor; M. J. Walsh; Y. Yang

2004-01-01

298

Telling Time  

NSDL National Science Digital Library

Students - These games will help you practice telling time and calculating time measurements. Students practice telling time from an analog clock. Play this game to figure out What time is it? Play this game at least 15 times, then come back and play another clock game. Students practice your telling time skills by clicking here. In this game you determine What time will it be?. Play this game at least 10 times. After ...

Udy, Mr.

2006-11-14

299

Estimation of test characteristics of real-time PCR and bacterial culture for diagnosis of subclinical intramammary infections with Streptococcus agalactiae in Danish dairy cattle in 2012 using latent class analysis.  

PubMed

The misdiagnosis of intramammary infections (IMI) with Streptococcus agalactiae (S. agalactiae) could lead farmers to treat or cull animals unnecessarily. The objective of this field study was to estimate the sensitivity (Se) and specificity (Sp) of real-time PCR at different cut-offs for cycle threshold (Ct) values against bacterial culture (BC) for diagnosis of S. agalactiae IMI using latent class analysis to avoid the assumption of a perfect reference test. A total of 614 dairy cows were randomly selected from 6 herds with bulk tank PCR Ct value ? 39 for S. agalactiae and S. aureus. At milk recording, 2456 quarter milk samples were taken aseptically for BC and the routinely taken cow level milk samples were analyzed by PCR. Results showed that 53 cows (8.6%) were positive for S. agalactiae IMI by BC. Sensitivity of PCR at cut-offs; ? 39, ? 37, ? 34, and ? 32, was 96.2%, 91.9%, 87.2% and 73.9%, while Se of BC was 25.7%, 29.9%, 59.9% and 72.1%. Specificity of PCR at cut-offs; ? 39, ? 37, ? 34, and ? 32, was 96.8%, 96.9%, 96.7%, and 97.22%, while Sp of BC was 99.7%, 99.5%, 99.2%, and 98.9%. The estimated prevalence of S. agalactiae IMI by PCR was higher than the apparent prevalence at the tested cut-offs, indicating under estimation of S. agalactiae IMI in the examined dairy cows. In conclusion, Se of PCR is always higher than Se of BC at all tested cut-offs. The lower cut-off, the more comparable becomes Se of PCR and Se of BC. The changes in Se in both PCR and BC at different Ct-value cut-offs may indicate a change in the definition of the latent infection. The similar Se of both tests at cut-off ? 32 may indicate high concentrations of S. agalactiae viable cells, representing a cow truly/heavily infected with S. agalactiae and thus easier to detect with BC. At cut-off ? 39 the latent definition of infection may reflect a more general condition of cows being positive for S. agalactiae. Our findings indicate that PCR Ct-value cut-offs should be chosen according to the underlying latent infection definition of interest. Latent class analysis proposes a useful alternative to classic test evaluation of diagnostic tests used for detection of S. agalactiae IMI in milk. PMID:23194895

Mahmmod, Yasser S; Toft, Nils; Katholm, Jørgen; Grønbæk, Carsten; Klaas, Ilka C

2013-05-01

300

Characteristic Evolution and Matching  

E-print Network

I review the development of numerical evolution codes for general relativity based upon the characteristic initial value problem. Progress in characteristic evolution is traced from the early stage of 1D feasibility studies to 2D axisymmetric codes that accurately simulate the oscillations and gravitational collapse of relativistic stars and to current 3D codes that provide pieces of a binary black hole spacetime. Cauchy codes have now been successful at simulating all aspects of the binary black hole problem inside an artificially constructed outer boundary. A prime application of characteristic evolution is to extend such simulations to null infinity where the waveform from the binary inspiral and merger can be unambiguously computed. This has now been accomplished by Cauchy-characteristic extraction, where data for the characteristic evolution is supplied by Cauchy data on an extraction worldtube inside the artificial outer boundary. The ultimate application of characteristic evolution is to eliminate the role of this outer boundary by constructing a global solution via Cauchy-characteristic matching. Progress in this direction is discussed.

Jeffrey Winicour

2008-10-10

301

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

302

Time Sequence Liquid Dominant  

E-print Network

Time Sequence Liquid Dominant Evaporation De-pinning Dryout Progress Formation of Nanoparticle of Nanofluid Droplets on a Microheater Array 2-nm Au 20nm 47-nm Al2O3 Distilled Water 30-nm CuO Microheater to examine the effect of nanoparticle sizes on the dryout characteristics. While the distilled water droplet

Kihm, IconKenneth David

303

PressurePressure Indiana Coal Characteristics  

E-print Network

TimeTime PressurePressure · Indiana Coal Characteristics · Indiana Coals for Coke · CoalTransportation in Indiana · Coal Slurry Ponds Evaluation · Site Selection for Coal Gasification · Coal-To-Liquids Study, CTL · Indiana Coal Forecasting · Under-Ground Coal Gasification · Benefits of Oxyfuel Combustion · Economic

Fernández-Juricic, Esteban

304

Aircraft compass characteristics  

NASA Technical Reports Server (NTRS)

A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Characteristics of Navy aircraft compasses IV to IX and some other compasses are shown for the range of temperatures experienced in flight. Results of flight tests are presented. These results indicate that the characteristic most desired in a steering compass is a short period and, in a check compass, a low overswing.

Peterson, John B; Smith, Clyde W

1937-01-01

305

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 ...

306

3D Characteristics  

NASA Technical Reports Server (NTRS)

Contributions to the Method of Characteristics in Three Dimensions, which previously received incomplete recognition, are reviewed. They mostly follow from a fundamental paper by Rusanov which led to several developments in Russia, described by Chushkin.

Holt, Maurice

1998-01-01

307

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

308

On recent developments in marginal separation theory  

PubMed Central

Thin aerofoils 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 aerofoil performance, they tend to ‘burst’ if ? is increased further or if perturbations acting upon the flow reach a certain intensity. This then either leads to global flow separation (stall) or triggers the laminar–turbulent transition process within the boundary layer flow. This paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number , commonly referred to as marginal separation theory. A new approach based on the adjoint operator method is presented that enables the fundamental similarity laws of marginal separation theory to be derived and the analysis to be extended 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 on its resolution being based on asymptotic arguments. The passage to the subsequent triple-deck stage is described in detail, which is a prerequisite for carrying out a future numerical treatment of this stage in a proper way. Moreover, a composite asymptotic model is developed in order for the inherent ill-posedness of the Cauchy problems associated with the current flow description to be resolved. PMID:24936013

Braun, S.; Scheichl, S.

2014-01-01

309

On recent developments in marginal separation theory.  

PubMed

Thin aerofoils 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 aerofoil performance, they tend to 'burst' if ? is increased further or if perturbations acting upon the flow reach a certain intensity. This then either leads to global flow separation (stall) or triggers the laminar-turbulent transition process within the boundary layer flow. This paper addresses the asymptotic analysis of the early stages of the latter phenomenon in the limit as the characteristic Reynolds number [Formula: see text], commonly referred to as marginal separation theory. A new approach based on the adjoint operator method is presented that enables the fundamental similarity laws of marginal separation theory to be derived and the analysis to be extended 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 on its resolution being based on asymptotic arguments. The passage to the subsequent triple-deck stage is described in detail, which is a prerequisite for carrying out a future numerical treatment of this stage in a proper way. Moreover, a composite asymptotic model is developed in order for the inherent ill-posedness of the Cauchy problems associated with the current flow description to be resolved. PMID:24936013

Braun, S; Scheichl, S

2014-07-28

310

Residential Housing Characteristics Survey 1997  

NSDL National Science Digital Library

Specific information such as how many homes have PCs, modems and FAX machines or how home appliance usage has changed over time (1978-1997) can now be obtained in this recently-released Residential Housing Characteristics Survey by the US Energy Information Administration. Nearly two decades of Regional Energy Consumption Surveys (RECS) on US households and their energy is contained on site in addition to supplementary maps, a glossary of terms, and documentation of EIA survey methods and data quality. To further facilitate research, the EIA provides a Data Table Home Page where users may choose variables and access data tables directly on site.

1998-01-01

311

Long Characteristic Method in Space and Time for Transport Problems  

E-print Network

the ?thick? diffusion limit. ( ) ( ) ( ) ( ) ( ) ( ) ( ) 1 1 , 1, , 2 , t s M M m m m m m m x x x q x x x w x w x y mm s y m s f f y m y = = ? + = + #11; #12; ? = = (3.1) 25 t t t s a q q ss e ss es e e fi fi - fi (3.2) Applying the scaling... the ?thick? diffusion limit. ( ) ( ) ( ) ( ) ( ) ( ) ( ) 1 1 , 1, , 2 , t s M M m m m m m m x x x q x x x w x w x y mm s y m s f f y m y = = ? + = + #11; #12; ? = = (3.1) 25 t t t s a q q ss e ss es e e fi fi - fi (3.2) Applying the scaling...

Pandya, Tara M.

2010-07-14

312

Characteristic relaxation times and their invariance to thermodynamic conditions  

E-print Network

and the forces between molecules. The relaxation behavior also governs to a large extent the physical. Representa- tive data are shown in Fig. 1 for a poly- mer, atactic-polypropylene (aPP),1 and a molecular

Weeks, Eric R.

313

animals --produce characteristic, heritable incubation times and patterns of brain  

E-print Network

in itsamino-acid(primary)sequence. At the genetic level, variations in the human prion gene that protect throughout human populations worldwide (J. Collinge, Inst. Neurology, London)4 . This provides a compelling they have been necessary? Collinge suggested that they protected against cannibalism-transmitted prion dis

Hays, Graeme

314

Pyroelectric anemometers and kinetic calorimeters. Annual report, April 1, 1991-March 31, 1992  

SciTech Connect

The pyroelectric anemometer (PA) is a new type of thermally based flow sensor. It has the advantage of utilizing a basic materials property, pyroelectricity, of certain classes of crystalline materials to directly measure the forced convective heat flow to a gas. As a consequence, the signal depends on the heat flow rather than the background temperature which enables the device to have performance characteristics superior to those of resistive anemometers. The goal of the study is to establish the thermal characteristics of the anemometer and its response to laminar, turbulent and swirling flow.

Hsieh, S.H.Y.; Zemel, J.N.

1992-07-01

315

Time Relationships.  

ERIC Educational Resources Information Center

Discusses ways that authors use time as it relates to the setting or time period, and to reveal changes throughout the story. Provides activities for elementary school students to help them understand how authors show time and changes, includes a worksheet to show examples of time relationships, and suggests assessment possibilities. (LRW)

Davis, Jonathan; Davis, Lisa

2001-01-01

316

Elapsed Time  

NSDL National Science Digital Library

This interactive Java applet allows the user to practice finding elapsed time using analog or digital clocks. Using the "See" mode the user advances a clock from the beginning time to the ending time and the applet calculates the elapsed time. Using the "Guess" mode, the user must calculate the elapsed time between the given beginning and ending times. Three difficulty levels allow the user to practice with hour, five minute, or single minute increments. An optional scoring feature allows the user to keep track of number correct, though this feature is optional.

2007-01-01

317

TIME MANAGEMENT Time Management Questionnaire  

E-print Network

TIME MANAGEMENT WORKSHOP #12;2 Time Management Questionnaire Self Assessment: Answer "Yes" or "No you tend to complete your assignments on time? 3. ____ Have you estimated how long it takes to read schedule time to study for exams? 8. ____ Do you have a job that requires more than 20 hours a week? 9

318

Propagators from characteristic surfaces  

E-print Network

We study the Goursat or characteristic problem, i.e. a hyperbolic equation with given data on a surface (the half of the standard Cauchy problem), with some kind of dimensional regularization procedure to deal with the divergences that appear. We will also comment some possible relation with a holographic setup.

Jorge Conde

2005-01-17

319

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

320

Characteristic Curves of PEMFC  

NSDL National Science Digital Library

This in-class exercise will allow students hands-on experience working with a proton exchange membrane fuel cell, or PEMFC. The class will examine the characteristic curve of one of these fuel cells and measure the voltage and current output of the cell. Step by step instructions are provided for the experiment. This document may be downloaded in PDF file format.

2012-07-11

321

Hypnosis, Demand Characteristics, and \\  

Microsoft Academic Search

In introducing the notion of demand characteristics, Martin T. Orne acknowledged his debt to Egon Brunswik (1947), who held similar views. Orne (1959) took it several steps further by proposing the real-simulator design as a means of evaluating the degree to which experimental outcomes might be artifactual of implicit cues in the design and\\/or procedure of empirical studies. By contrast,

Campbell Perry

2002-01-01

322

Characteristics of Manipulators  

Microsoft Academic Search

This article investigates the problem of manipula- tor design for increased dynamic performance. Opti- mization techniques are used to determine the design parameters which improve manipulator performance. The dynamic ,performance of a manipulator is char- acterized by the inertial and acceleration properties of the end-effector. Our study of inertial and accelera- tion properties have provided separate descriptions of the characteristics

Oussama Khatib; Alan Bowling

323

Behavioural characteristics of rapists  

Microsoft Academic Search

A substantial proportion of past research on rapists has focused on their motives. This paper reports on two studies that investigated the behavioural characteristics of rapists. The first study gathered behavioural data from police rape files to determine the types of behaviours exhibited by 130 men charged with rape. The second study was designed to validate the behavioural clusters found

Marita P. McCabe; Michelle Wauchope

2005-01-01

324

Personality Characteristics of Engineers  

ERIC Educational Resources Information Center

The objective of the current study was to investigate the personality characteristics of a group of engineers with a variety of years of experience. It was executed to remedy shortcomings of the literature concerning this issue and to produce suggestions for a postgraduate training programme for engineers. A total of 103 engineers were tested with…

van der Molen, Henk T.; Schmidt, Henk G.; Kruisman, Gerard

2007-01-01

325

Developmental Time  

Microsoft Academic Search

The concept of developmental time is proposed as a method for organizing family therapy interventions. Developmental time is the point in the family life cycle that a family expects to be occupying given the age and stage of its members. We promote alterations in the normative time frame by encouraging family members to relive previous developmental transitions or enact anticipated

Stephen A. Anderson; William M. Boylin

2000-01-01

326

Time lapse  

NSDL National Science Digital Library

Time lapse videos and photography allow us to visualize parts of certain events that we wouldn't normally be able to piece together. Since decay takes time, the causal relationships of this phenomenon can be seen through the use of time lapse videos.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-16

327

Modelling Time  

E-print Network

We briefly review two concepts of time - the usual time associated with "being" and more recent ideas, answering to the description of "becoming". The approximation involved in the former is examined. Finally we argue that it is (unpredictable) fluctuations that underlie time.

Burra G. Sidharth

2008-09-03

328

Reaction Time  

NSDL National Science Digital Library

In this activity, learners explore reaction time and challenge themselves to improve their coordination. Do you want to move faster? Catch that ball that you never seem to see in time? Use a simple test to help you improve your reaction (or response) time.

Science, New Y.

1999-01-01

329

Investigation of dispersion characteristic in tapered fiber  

NASA Astrophysics Data System (ADS)

A dispersion characteristic of a tapered fiber is investigated using temporal interferometer by employing a broadband amplified spontaneous emission (ASE) source to generate an interference pattern. The dispersion characteristic of the tapered fiber is acquired from a Fourier transform of the interference pattern. The second and third order dispersions of ?2 and ?3 are obtained at 1544.1 nm for -600 ps2/km and -2 ps3/km, respectively. The ?2 value obtained is observed to be more than 300 times higher than that of a non-tapered single mode fiber. The high dispersion characteristic is due to tapering process that changes the birefringence characteristic due to the reduction in the fiber's size and structure.

Harun, S. W.; Lim, K. S.; Ahmad, H.

2011-05-01

330

Quantum Time  

E-print Network

Normally we quantize along the space dimensions but treat time classically. But from relativity we expect a high level of symmetry between time and space. What happens if we quantize time using the same rules we use to quantize space? To do this, we generalize the paths in the Feynman path integral to include paths that vary in time as well as in space. We use Morlet wavelet decomposition to ensure convergence and normalization of the path integrals. We derive the Schr\\"odinger equation in four dimensions from the short time limit of the path integral expression. We verify that we recover standard quantum theory in the non-relativistic, semi-classical, and long time limits. Quantum time is an experiment factory: most foundational experiments in quantum mechanics can be modified in a way that makes them tests of quantum time. We look at single and double slits in time, scattering by time-varying electric and magnetic fields, and the Aharonov-Bohm effect in time.

John Ashmead

2010-05-05

331

Photodetector and Receiver Characteristics  

NSDL National Science Digital Library

In this video from the ICT Center, learn about fiber optic receivers. Investigate the components of an optical receiver; how a photodetector converts an optical signal to an electrical one; and the characteristics of PIN, avalanche, and metal-semiconductor-metal photodiodes.The video runs 2:07 and is accompanied by a background essay, standards alignment, and discussion questions. Users who sign up for a free account can save the resource and download the video as well.

2012-06-04

332

The Variance Reaction Time Model  

ERIC Educational Resources Information Center

The variance reaction time model (VRTM) is proposed to account for various recognition data on reaction time, the mirror effect, receiver-operating-characteristic (ROC) curves, etc. The model is based on simple and plausible assumptions within a neural network: VRTM is a two layer neural network where one layer represents items and one layer…

Sikstrom, Sverker

2004-01-01

333

Modeling data with multiple time dimensions  

Microsoft Academic Search

A large class of problems in time series analysis can be represented by a set of overlapping time series with different starting times. These time series may be treated as different probes of the same underlying process. Such probes may follow a characteristic lifecycle as a function of the time since the series began. They may also be subject to

Joseph L. Breeden

2007-01-01

334

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

335

Ozonation characteristics of bisphenol a in water  

Microsoft Academic Search

Ozonation characteristics of bisphenol A were investigated as a function of gaseous ozone dose, initial concentration of bisphenol A, pH, radical scavenger (tert?butanol), and radical initiator (hydrogen peroxide). The ozonation led to a complete removal of bisphenol A in water within a certain period of time. The overall rate of the ozonation linearly increased with the ozone dose. The stoichiometry

J. Lee; J. Yoon

2003-01-01

336

Sensitometric characteristics of dental xeroradiography  

SciTech Connect

Dental xeroradiography is a high-quality intraoral imaging system which provides a potentially convenient, rapid, low-dose alternative to conventional film radiography. In this study the sensitometric properties of dental xeroradiography were investigated via assessment of high- and low-contrast xeroradiographic processor settings, transmission versus reflection densitometry, reciprocity-law failure, and kVp (tube voltage) plate dependence. Findings of the study indicated that imaging at high-contrast processor settings results in greater dynamic range but less exposure latitude than imaging at low-contrast processor settings. Determination of characteristic curves demonstrated greater contrast in reflection mode than imaging by transillumination for all but the very densest of images (greater than 1.6 O.D.). There was also little difference in characteristic curves produced from 50 to 90 kVp, indicating that the xeroradiographic plate exhibits a relatively constant sensitivity over the tube voltages tested if exposure is expressed in roentgens. Finally, no substantial reciprocity-law failure was observed for dental xeroradiography over a clinically relevant range of exposure times.

Gratt, B.M.; Sickles, E.A.

1983-11-01

337

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

338

Time Machine  

NSDL National Science Digital Library

In this lesson students will experience how geological and biological events have occurred in a clear sequence of vast but measured time. Students are taken on a simulated voyage backward in time, to the beginning of our planet. They witness that beginning, the origin of life, and a number of key events leading to the present. This becomes a dramatic experience, involving body and mind, helping students to relate physically at least to the relative timing of events in geological and biological history, if not to the absolute vastness of that time.

Flammer, Larry

339

Geological Time  

NSDL National Science Digital Library

"Why do engineers need to know about geologic time?" That question is answered in this resource from the University of Saskatchewan's Department of Civil and Geological Engineering. Provided here is a discussion of the concepts of geological time; relative dating methods, such as correlation; and absolute dating methods, such as radiometric methods. Diagrams and charts are included to demonstrate these complex concepts.

2008-04-17

340

Managing Time.  

ERIC Educational Resources Information Center

This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household…

Murphy, Linda; Della Corte, Suzanne

1991-01-01

341

Screen Time  

NSDL National Science Digital Library

This game asks you a series of questions about how much time you spend in front of a screen, not being active. It begins by pointing out that since we spend a lot of time in front of computer screens at work or school, additional time at home can really affect how healthy we are. It asks how much time you spend watching TV, playing computer games, and using the computer each day. It then adds up the total amount of screen time you spend every day, and calculates how many hours you spend a year in front of a screen. It also tells you if that's a healthy amount, and suggests ways to stay active while in front of screens.

Omsi

2007-01-01

342

Time Clocks  

NSDL National Science Digital Library

This exercise can be used to demonstrate changes in the Earth through time, and the length of time it took for those changes to take place. A list of Important Dates in Earth History is provided that contains the dates of the events shown on a time clock. The teacher can pick events from the list of key events and calculate (or have students calculate) the time for the key events they wish to use. A page-size image of the clock can be printed and turned into an overhead transparency. To better demonstrate the changes since the beginning of the Paleozoic Era, the same exercise could be done the second day of class, using only the last 570 million years of time.

Greb, Stephen

343

Finding time.  

PubMed

We understand time through our models of it. These are typically models of our physical chronometers, which we then project into our subjects. A few of these models of the nature of time and its effects on the behavior of organisms are reviewed. New models, such as thermodynamics and spectral decomposition, are recommended for the potential insights that they afford. In all cases, associations are essential features of timing. To make them, time must be discretized by stimuli such as hours, minutes, conditioned stimuli, trials, and contexts in general. Any one association is seldom completely dominant, but rather shares control through proximity in a multidimensional space, important dimensions of which may include physical space and time as rendered by Fourier transforms. PMID:23973706

Killeen, Peter R

2014-01-01

344

Wave Types and Characteristics  

NSDL National Science Digital Library

This is the first in a series of new marine meteorology modules based on COMETâs old laser disk and CD-ROM modules on marine meteorology. 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 dispersion.

Comet

2003-07-31

345

LED and Transmitter Characteristics  

NSDL National Science Digital Library

In this video from the ICT Center, learn about fiber optic transmitters. Explore the components of a fiber optic transmitter, including a source, a modulator, an electrical driving circuit, and fiber coupling mechanics. Animations illustrate how the process of spontaneous emission converts electrical information to an optical signal in a light-emitting diode, or LED. In addition, learn about characteristics that make a source suitable for fiber optic communications.The video runs 3:12 and is accompanied by a background essay, standards alignment, and discussion questions. Users who sign up for a free account can save the resource and download the video as well.

2012-05-30

346

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.

347

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. PMID:23881131

Chong, Su Sin; Abdul Aziz, A. R.; Harun, Sulaiman W.

2013-01-01

348

Time warps  

E-print Network

I reconsider asymmetrically warped compactifications, in which time and space have different warp factors. I call such compactifications time warps if the bulk geometry has neither entropy nor temperature. I provide an example starting from an asymptotically AdS_5 spacetime where the speed of light, measured in a fixed coordinate system, is larger near the boundary than it is deep in the interior. This example follows the general plan of earlier work on superconducting black holes. To obtain a normalizable, four-dimensional graviton, one can introduce a Planck brane whose action includes a wrong-sign Einstein-Hilbert term. The equation of state of the Planck brane has w time warp geometry. Time warps of the type I describe provide an extra-dimensional description of boost invariance as an emergent symmetry in the infrared. High-energy violations of Lorent...

Gubser, Steven S

2008-01-01

349

Time outs  

MedlinePLUS

... Time-out technique for discipline. Children's Health Network web site. http://www.childrenshealthnetwork.org/CRS/CRS/pa_ ... a break from negative behavior. Massachusetts Medical Society web site. http://www.massmed.org/patient-care/health- ...

350

Time Management  

NSDL National Science Digital Library

This section of Mind Tools teaches you time management skills. These are the simple, practical techniques that have helped the leading people in business, sport and public service reach the pinnacles of their careers.

MindTools (MindTools)

2012-01-20

351

Timing During Interruptions in Timing  

ERIC Educational Resources Information Center

Duration and location of breaks in time interval production were manipulated in various conditions of stimulus presentation (Experiments 1-4). Produced intervals shortened and then stabilized as break duration lengthened, suggesting that participants used the break as a preparatory period to restart timing as quickly as possible at the end of the…

Fortin, Claudette; Bedard, Marie-Claude; Champagne, Julie

2005-01-01

352

Time warps  

Microsoft Academic Search

I reconsider asymmetrically warped compactifications, in which time and space have different warp factors. I call such compactifications\\u000a time warps if the bulk geometry has neither entropy nor temperature. I provide an example starting from an asymptotically\\u000a AdS\\u000a 5 spacetime where the speed of light, measured in a fixed coordinate system, is larger near the boundary than it is deep

Steven S. Gubser

2010-01-01

353

Real time automated inspection  

DOEpatents

A method and apparatus are described 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 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. 43 figs.

Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

1985-05-21

354

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

355

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

356

Growth Characteristics of Organisms  

NASA Astrophysics Data System (ADS)

In this chapter a systems viewpoint is taken of the growth characteristics of normal and malignant tissue. We find that such growth is well analyzed by the concepts of Shannon and Fisher information. In Section 3.1 conventional mechanisms of information transmission via DNA, RNA, and proteins are identified, as well as unconventional structures such as lipids and ion gradients. Information storage, flow, and utilization are analyzed, both within cells and over a system of cells. In Section 3.2, malignant tissue growth is found to be accurately described by the use of Fisher information in particular. Cancer growth is seen to occur as a disease of information, in fact an information catastrophe due to the regression of cells to a minimally ordered state consistent with life. The analysis yields many predictions about the growth of healthy tissue and cancerous tissue, some of which are nonintuitive and have a strong bearing on cancer diagnosis and treatment.

Gatenby, Robert A.; Frieden, B. Roy

357

[Characteristics of aging skin].  

PubMed

The change in the population's age structure in most industrial countries, as in Germany, requires geriatric medicine to play an increasingly important role. Dermatology also has to meet the new challenges by expert discussion and ethical considerations. The physiological aging process is influenced by intrinsic and extrinsic factors and causes a variety of morphological and functional alterations in the skin. Those alterations are the cause for an increasing prevalence of many dermatoses. Infections, wound healing disorders, inflammatory diseases, tumors and associated paraneoplastic syndromes are of particular importance. The structural and functional characteristics of aging skin in combination with the reduced mobility and declining cognitive abilities in elder patients require specific recommendations for skin protection as well as qualified advice about topical and systemic use of medications. PMID:25231590

Wohlrab, J; Hilpert, K; Wohlrab, A

2014-10-01

358

Wafer characteristics via reflectometry  

DOEpatents

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

359

Delrin material characteristics.  

PubMed

Delrin acetal resin, a product of DuPont, is formed from the polymerization of formaldehyde. The tightly interlocked helical molecules and high crystallinity result in excellent mechanical properties. Its superiority in tensile strength, stiffness, creep resistance, and fatigue classify it as an "engineering resin', a term used for plastics which can compete with metals in many applications. One of the important characteristics separating Delrin from other engineering plastics such as polyamides (nylons) is its very low water absorption and the small effect of aqueous solutions on its properties. The structure of Delrin is reviewed on several levels: chemical, crystallographic, lamellar, and spherulitic. The relationship of the structure to the properties of moldings of Delrin is discussed. PMID:8905519

Clark, E S

1996-08-01

360

Video Game Structural Characteristics: A New Psychological Taxonomy  

Microsoft Academic Search

Excessive video game playing behaviour may be influenced by a variety of factors including the structural characteristics\\u000a of video games. Structural characteristics refer to those features inherent within the video game itself that may facilitate\\u000a initiation, development and maintenance of video game playing over time. Numerous structural characteristics that influence\\u000a gambling frequency and expenditure have been identified in the gambling

Daniel King; Paul Delfabbro; Mark Griffiths

2010-01-01

361

Time 100  

NSDL National Science Digital Library

This Time Warner Pathfinder (discussed in the November 11, 1994 Scout Report) Time Magazine site, released to coincide with a Time cover story of the same title, is the first in what is to be a five part site that will eventually cover 100 of the 20th Century's most influential people. At present the site contains profiles of 20 of the century's most influential "leaders & revolutionaries," including Margaret Sanger, Vladimir Lenin, Winston Churchill, Dr. Martin Luther King, Jr., Ayatolla Ruholla Khomeini, and the anonymous Chinese protester who blocked the tank in the Tienanmen Square protest in 1989. Stories about the personalities by such authors as Gloria Steinem, Arthur Schlesinger, Jr., Salman Rushdie, Elie Wiesel, and Stanley Karnow, among others, highlight the site. There is also a timeline of each personality, as well as a timeline of the century. For the personalities who were covered by Time, an original in-depth story from the Time archives is available. Forthcoming throughout 1998 and 1999 are sections on "entertainers & artists, builders & titans, scientists & thinkers, and heroes and inspirations." The site is also available in a Shockwave Flash version.

1998-01-01

362

Time warps  

E-print Network

I reconsider asymmetrically warped compactifications, in which time and space have different warp factors. I call such compactifications time warps if the bulk geometry has neither entropy nor temperature. I provide an example starting from an asymptotically AdS_5 spacetime where the speed of light, measured in a fixed coordinate system, is larger near the boundary than it is deep in the interior. This example follows the general plan of earlier work on superconducting black holes. To obtain a normalizable, four-dimensional graviton, one can introduce a Planck brane whose action includes a wrong-sign Einstein-Hilbert term. The equation of state of the Planck brane has w time warp geometry. Time warps of the type I describe provide an extra-dimensional description of boost invariance as an emergent symmetry in the infrared. High-energy violations of Lorentz symmetry, if confined to a strongly coupled unparticle sector dual to the time warp geometry, might manifest themselves through unusual kinematic constraints. As an example, I explain how modifications of unparticle phase space would affect the decay of a heavy particle into a light visible sector particle plus unparticle stuff.

Steven S. Gubser

2008-12-30

363

Persistence Characteristics of Stormwater BMPs  

E-print Network

Characteristics Temperature Conductivity pH Dissolved Oxygen Turbidity Nutrients Organic Carbon #12;6 What Are "Ambient", "Natural", or "Predevelopment" Characteristics? Water quantity Water quality #12;4 Water Quantity Characteristics Base flow Median flow Dominant discharge Variability Memory #12;5 Water Quality

364

Gender, work roles and psychosocial work characteristics as determinants of health  

Microsoft Academic Search

This paper aims to identify gender similarities and differences in psychosocial work characteristics for those in and out of paid employment, to inform research on possible health-related effects. Specifically five questions are addressed: do women report poorer work characteristics than men; are gender differences related to specific characteristics; do work characteristics differ between full- and part-time women workers and between

Sharon Matthews; Clyde Hertzman; Aleck Ostry; Chris Power

1998-01-01

365

"Forget time"  

E-print Network

Following a line of research that I have developed for several years, I argue that the best strategy for understanding quantum gravity is to build a picture of the physical world where the notion of time plays no role. I summarize here this point of view, explaining why I think that in a fundamental description of nature we must "forget time", and how this can be done in the classical and in the quantum theory. The idea is to develop a formalism that treats dependent and independent variables on the same footing. In short, I propose to interpret mechanics as a theory of relations between variables, rather than the theory of the evolution of variables in time.

Carlo Rovelli

2009-03-23

366

Deep Time  

NSDL National Science Digital Library

Earth has been significantly altered over its 4.6 billion year history by climate swings, volcanism, and drifting continents. These dynamic conditions, in turn, have influenced every living thing that has inhabited the planet. This interactive timeline discusses the concept of deep time, and allows users to learn about geological events, evolutionary transformations, and the extinction of species or whole families of organisms that once inhabited the planet, and to better appreciate the vast period of time over which these transformations have occurred. A background essay and discussion questions are included.

367

An Implicit Characteristic Based Method for Electromagnetics  

NASA Technical Reports Server (NTRS)

An implicit characteristic-based approach for numerical solution of Maxwell's time-dependent curl equations in flux conservative form is introduced. This method combines a characteristic based finite difference spatial approximation with an implicit lower-upper approximate factorization (LU/AF) time integration scheme. This approach is advantageous for three-dimensional applications because the characteristic differencing enables a two-factor approximate factorization that retains its unconditional stability in three space dimensions, and it does not require solution of tridiagonal systems. Results are given both for a Fourier analysis of stability, damping and dispersion properties, and for one-dimensional model problems involving propagation and scattering for free space and dielectric materials using both uniform and nonuniform grids. The explicit Finite Difference Time Domain Method (FDTD) algorithm is used as a convenient reference algorithm for comparison. The one-dimensional results indicate that for low frequency problems on a highly resolved uniform or nonuniform grid, this LU/AF algorithm can produce accurate solutions at Courant numbers significantly greater than one, with a corresponding improvement in efficiency for simulating a given period of time. This approach appears promising for development of dispersion optimized LU/AF schemes for three dimensional applications.

Beggs, John H.; Briley, W. Roger

2001-01-01

368

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

369

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

370

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

371

Regional relationships between basin size and runoff characteristics  

Microsoft Academic Search

The effect of basin size on runoff characteristics is investigated. The maximum observed floodflow, the maximum annual constant loss, the lag time and the unitgraph peak for a certain storm duration of basins in the western and northwestern regions of Greece are increasing power functions of the basin size. These functions explain significantly the variation in the runoff characteristics. For

MARIA MIMIKOU

1984-01-01

372

8-, 16-, and 32-Bit Processors: Characteristics and Appropriate Applications.  

ERIC Educational Resources Information Center

Defines and describes the components and functions that constitute a microcomputer--bits, bytes, address register, cycle time, data path, and bus. Characteristics of 8-, 16-, and 32-bit machines are explained in detail, and microprocessor evolution, architecture, and implementation are discussed. Application characteristics or types for each bit…

Williams, James G.

1984-01-01

373

Firm characteristics, total quality management, and financial performance  

Microsoft Academic Search

This paper uses a sample of quality award winners to empirically test hypotheses that relate changes in operating income associated with effective implementation of total quality management (TQM) to various firm characteristics. The characteristics examined are firm size, the degree of capital intensity, the degree of diversification, the timing of TQM implementation, and the maturity of the program. We find

Kevin B. Hendricks; Vinod R. Singhal

2000-01-01

374

Firm characteristics, total quality management, and financial performance  

Microsoft Academic Search

This paper uses a sample of quality award winners to empirically test hypotheses that relate changes in operating income associated with effective implementation of total quality management (TQM) to various firm characteristics. The characteristics examined are firm size, the degree of capital intensity, the degree of diversification, the timing of TQM implementation, and the maturity of the program. We find

Kevin B Hendricks; Vinod R Singhal

2001-01-01

375

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

376

Time-Distance Helioseismology  

NASA Technical Reports Server (NTRS)

Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

Duvall, Thomas L., Jr.

2010-01-01

377

28 CFR 544.82 - General program characteristics.  

Code of Federal Regulations, 2011 CFR

...Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT EDUCATION Education, Training and Leisure-Time Program Standards § 544.82 General program characteristics. (a) The Supervisor of Education shall...

2011-07-01

378

28 CFR 544.82 - General program characteristics.  

Code of Federal Regulations, 2010 CFR

...Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT EDUCATION Education, Training and Leisure-Time Program Standards § 544.82 General program characteristics. (a) The Supervisor of Education shall...

2010-07-01

379

28 CFR 544.82 - General program characteristics.  

Code of Federal Regulations, 2012 CFR

...Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT EDUCATION Education, Training and Leisure-Time Program Standards § 544.82 General program characteristics. (a) The Supervisor of Education shall...

2012-07-01

380

28 CFR 544.82 - General program characteristics.  

Code of Federal Regulations, 2013 CFR

...Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT EDUCATION Education, Training and Leisure-Time Program Standards § 544.82 General program characteristics. (a) The Supervisor of Education shall...

2013-07-01

381

Young Children's Sibling Relationship Interactional Types: Associations with Family Characteristics, Parenting, and Child Characteristics  

ERIC Educational Resources Information Center

Research Findings: This study examines patterns of sibling relationship qualities or interactional types and their association with family characteristics, parenting, and the characteristics of 1 of those children. Participants were 65 children (34 boys; Time 1 mean age = 51 months), their mothers, fathers, and Head Start teachers. Approximately…

Gamble, Wendy C.; Yu, Jeong Jin

2014-01-01

382

Noise characteristics in IFOG  

NASA Astrophysics Data System (ADS)

IFOG (Interferometric Fiber Optic Gyroscope) is the most promising angular velocity sensor in the inertial guidance market due to its attractive advantages, which is often regarded as the next generation gyro that can ultimately replace the traditional mechanical gyroscope. In order to improve the performance of IFOG, especially to low down the bias drift and angle random walk (ARW) of IFOG, it is valuable to research the noise characteristics of IFOG. In this paper, the ultra low frequency random noise and the relatively high frequency random noise has been investigated respectively. The experimental data of a practical open loop IFOG is obtained by different sampling frequency, through which the different frequency scope of the noise can be researched separately. The frequency spectral analysis of the noise deduces the follow result: (1) the relative high frequency (higher than about 0.001 Hz) random noise can be approximately modeled as Gaussian white noise (GWN), and its spectral range is determined by the system bandwidth of IFOG. The angle random walk of IFOG is determined by this kind of noise. (2) The ultra low frequency (lower than about 0.001 Hz) random noise can not be Gaussian white noise, which is much more great than other noises, and with the rise of frequency, the power of the relevant frequency component is lower down sharply. The ultra low frequency noise is often regarded as the source of bias drift of IFOG.

Chang, Jianxin; Wang, Peng; Qin, BingKun; Chen, Shufen

2000-10-01

383

Arcjet load characteristics  

NASA Technical Reports Server (NTRS)

Experiments were conducted to define the interface characteristics and constraints of 1 kW class arcjets run on simulated decomposition products of hydrazine and power processors. The impacts of power supply output current ripple on arcjet performance were assessed by variation of the ripple frequency from 100 Hz to 100 kHz with 10 percent peak-to-peak ripple amplitude at 1.2 kW. Ripple had no significant effects on thrust, specific impulse or efficiency. The impact of output ripple on thruster lifetime was not assessed. The static and dynamic impedances of the arcjet were quantified with two thrusters of nearly identical configuration. Superposition of an AC component on the DC arc current was used to characterize the dynamic impedance as a function of flow rate and DC current level. A mathematical model was formulated from these data. Both the static and dynamic impedance magnitude were found to be dependent on mass flow rate. The amplitude of the AC component was found to have little effect on the dynamic impedance. Reducing the DC level from 10 to 8 amps led to a large change in the magnitude of the dynamic impedance with no observable phase change. The impedance data compared favorably between the two thrusters.

Hamley, John A.

1990-01-01

384

Wetting Characteristics of Immiscibles  

NASA Technical Reports Server (NTRS)

Early microgravity experiments with immiscible alloys were usually carried out with the intent of forming dispersed microstructures. By processing under microgravity conditions, the main mechanism leading to gross phase separation could be eliminated. However, analysis of flight samples revealed a separated structure where the minor phase was present along the outer surface, while the major phase was present in the center. The Wetting Characteristics of Immiscibles (WCI) project, which flew aboard the USMP-4 (United States Microgravity Payload) mission in November of 1997, was designed to gain insight into the mechanisms causing segregation of these alloys. This investigation utilized an immiscible transparent organic alloy system and a transparent container in order to facilitate direct observation of the separation process. A range of immiscible alloy compositions was utilized in order to obtain variations in the minor and major phases present and observe the influence on the segregation processes. A small composition range was found where the minor liquid phase perfectly wet the cell gasket. Unexplained observations were made at the extremes of the composition range.

Andrews, J. B.; Little, L. J.

1999-01-01

385

Sensor Characteristics Reference Guide  

SciTech Connect

The Buildings Technologies Office (BTO), within the U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), is initiating a new program in Sensor and Controls. The vision of this program is: • Buildings operating automatically and continuously at peak energy efficiency over their lifetimes and interoperating effectively with the electric power grid. • Buildings that are self-configuring, self-commissioning, self-learning, self-diagnosing, self-healing, and self-transacting to enable continuous peak performance. • Lower overall building operating costs and higher asset valuation. The overarching goal is to capture 30% energy savings by enhanced management of energy consuming assets and systems through development of cost-effective sensors and controls. One step in achieving this vision is the publication of this Sensor Characteristics Reference Guide. The purpose of the guide is to inform building owners and operators of the current status, capabilities, and limitations of sensor technologies. It is hoped that this guide will aid in the design and procurement process and result in successful implementation of building sensor and control systems. DOE will also use this guide to identify research priorities, develop future specifications for potential market adoption, and provide market clarity through unbiased information

Cree, Johnathan V.; Dansu, A.; Fuhr, P.; Lanzisera, Steven M.; McIntyre, T.; Muehleisen, Ralph T.; Starke, M.; Banerjee, Pranab; Kuruganti, T.; Castello, C.

2013-04-01

386

Time Remains  

E-print Network

On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of "change as relative variation" leads to a "fundamentally timeless" formalism for quantum gravity. Here, we will show how one may avoid this acute `problem of time'. Under our view, duration is still regarded as relative, but temporal succession is taken to be absolute. Following our approach, which is presented in more formal terms in arXiv:1303.7139, it is possible to conceive of a genuinely dynamical theory of quantum gravity within which time, in a substantive sense, remains.

Sean Gryb; Karim Thebault

2014-08-12

387

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

388

accelerates Slow time Fast time  

E-print Network

= gravity (complexity) Programmer Computer Earth Figure 2: TIME WARP (Tower Paradox, effects of gravity here clocks freeze BLACK HOLE even horizon Programmer's view Computer's view Figure 5: The speed-up effect can be made "infinite" by using a black hole. 5 #12;Rotating Black Hole all signals sent

389

Nonequilibrium thermodynamics and the optimal path to turbulence in shear flows.  

PubMed

We determine the initial condition on the laminar-turbulent boundary closest to the laminar state using nonlinear optimization for plane Couette flow. Resorting to the general evolution criterion of nonequilibrium systems we optimize the route to the statistically steady turbulent state, i.e., the state characterized by the largest entropy production. This is the first time information from the fully turbulent state is included in the optimization procedure. We demonstrate that the optimal initial condition is localized in space for realistic flow domains. PMID:21517387

Monokrousos, Antonios; Bottaro, Alessandro; Brandt, Luca; Di Vita, Andrea; Henningson, Dan S

2011-04-01

390

Radiographic amplifier screens: Fabrication process and characteristics  

NASA Technical Reports Server (NTRS)

The fabrication process and transfer characteristics for solid state radiographic image transducers (radiographic amplifier screens) is described. These screens were developed for use in real time nondestructive evaluation procedures that require large format radiographic images with contrast and resolution capabilities unavailable with conventional fluoroscopic screens. This work was directed toward screens usable for inmotion, on-line radiographic inspection by means of closed circuit television.

Szepesi, Z. P.

1977-01-01

391

Characteristics of flight simulator visual systems  

NASA Technical Reports Server (NTRS)

The physical parameters of the flight simulator visual system that characterize the system and determine its fidelity are identified and defined. The characteristics of visual simulation systems are discussed in terms of the basic categories of spatial, energy, and temporal properties corresponding to the three fundamental quantities of length, mass, and time. Each of these parameters are further addressed in relation to its effect, its appropriate units or descriptors, methods of measurement, and its use or importance to image quality.

Statler, I. C. (editor)

1981-01-01

392

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

393

Autoignition characteristics of no. 2 diesel fuel  

NASA Technical Reports Server (NTRS)

Parametric tests to map the ignition delay characteristics were conducted at pressures of 3, 4, and 5 atm, inlet air temperatures up to 1150 K and fuel air equivalence ratios ranging from 0.2 to 1.0. Ignition delay times in the range of 6 msec to 60 msec at freestream flow velocities ranging from 10 m/sec to 40 m/sec were obtained. The ignition delay times appeared to correlate with the inverse of pressure and the inverse exponent of temperature.

Tevelde, J. A.; Spadaccini, L. J.

1981-01-01

394

Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time  

E-print Network

Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Amy:56:27.6 Deborah Mc Eligot Deborah Storrings Male Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Macon Fessenden 20 1 5:42.2 2 0:26.9 1 34:29.7 3:23 1 0:12.8 1 17:41.1 3

Suzuki, Masatsugu

395

Gases: Characteristics and Properties  

NSDL National Science Digital Library

The first site related to ideal gas, called Ideal and Real Gas Laws, is maintained by Liina Ladon of Townsen University (1). Visitors can read about the properties of ideal gases, what the ideal gas law is, how to use it, and much more. The next site, titled Gas Laws, (2) is offered by the Ohio State University Department of Chemistry. This interactive site contains Shockwave movies of animations and audio files that describe what a gas is, the Ideal Gas Law equation, mixtures of gases, and problems using the ideal gas law. The University of Oregon site, Virtual Laboratory, teaches about the ideal gas law on the Welcome to the Pressure Chamber page (3). Those who enjoy online interaction will enjoy being able to control the action of a piston in a pressure chamber to see how the gases inside react. The fourth site includes another fun multimedia activity related to ideal gases provided by the Department of Physics and Astronomy at Western Washington University. The Air Filled Balloon in Liquid Nitrogen (4) movie shows an actual experiment of the effects on a balloon that's covered with liquid nitrogen. The page contains some additional information on the science behind the observations. The next site, called Ideal Gas Equations (5) is an online calculator that's part of Kean University's Department of Geology and Meteorology Web site. Users can calculate the pressure, volume, or temperature of a gas by inputting known variables into the various forms. Several methods and variations of calculating the values are provided as well as brief instructions. The next page from North Carolina State University's Basic Concepts in Environmental Science Web site is called Characteristics of Gases (6). Part of a larger learning module, the lesson plans objective is to use the ideal gas law to determine gas volumes at different absolute temperatures and absolute pressures. Everything needed to conduct the activity is provided including links to a volume calculator and practice problems. The seventh site is another animation that illustrates how gases react, called Molecular Model for an Ideal Gas (7). By changing the number of molecules in the chamber, their velocity, and the pressure and width of the container, users get to see how the molecules react to the conditions. The last site, Gases and Their Properties, is maintained by the Electronic Teaching Assistance Program(8). Students learn about the history of gas science, how gas laws describe ideal gases, what Dalton's Law and Graham's Law are, and much more.

Brieske, Joel A.

396

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

397

New Trends in Real Time Operating Systems  

Microsoft Academic Search

Most of today's embedded systems are required to work in dynamic environments, where the characteristics of the computational load cannot always be predicted in advance. Still timely responses to events have to be provided within precise timing constraints in order to guarantee a desired level of performance. Hence, embedded systems are, by nature, inherently real-time. Moreover, most of embedded systems

Shraddha S. Nakate; B. Meshram; Jayamala P. Chavan

2012-01-01

398

Multiple steady states for characteristic initial value problems  

NASA Technical Reports Server (NTRS)

The time dependent, isentropic, quasi-one-dimensional equations of gas dynamics and other model equations are considered under the constraint of characteristic boundary conditions. Analysis of the time evolution shows how different initial data may lead to different steady states and how seemingly anamolous behavior of the solution may be resolved. Numerical experimentation using time consistent explicit algorithms verifies the conclusions of the analysis. The use of implicit schemes with very large time steps leads to erroneous results.

Salas, M. D.; Abarbanel, S.; Gottlieb, D.

1984-01-01

399

Similarity Match in Time Series Streams under Dynamic Time Warping Distance  

Microsoft Academic Search

Time series streams have very wide applications in recent years, more and more scenarios need similarity match in time series streams and it becomes a hot research topic. Due to the fast online arrival and time-critical characteristics, the similarity measure should support handling the variable lengths sequence pairs. Dynamic Time Warping distance suits the request. But it has the disadvantage

Guiling Li; Yuanzhen Wang; Min Li; Zongda Wu

2008-01-01

400

Surface characteristics of lead ice  

Microsoft Academic Search

Under cold conditions, ice growth in a lead occurs rapidly, giving young sea ice a high bulk salinity. The surface characteristics of this ice type are dominated by a thin, highly saline surface skim and often by the formation of frost flowers. These surface characteristics are of particular interest because of their significant temporal variability and large impact on the

Donald K. Perovich; Jacqueline A. Richter-Menge

1994-01-01

401

A Taxonomy of Usability Characteristics  

E-print Network

A Taxonomy of Usability Characteristics in Virtual Environments Deliverable to Office of Naval This document can be found at http://csgrad.cs.vt.edu/jgabbard/ve/taxonomy/ #12;#12;A Taxonomy of Usability accomplished, yielding a comprehensive multi-dimensional taxonomy of usability characteristics specifically

Gabbard, Joseph L.

402

Characteristics of Ethical Business Cultures  

ERIC Educational Resources Information Center

The purpose of this study was to identify general characteristics attributed to ethical business cultures by executives from a variety of industries. Our research identified five clusters of characteristics: (1) Mission- and Values-Driven; (2) Stakeholder Balance; (3) Leadership Effectiveness; (4) Process Integrity; and (5) Long-term Perspective.…

Ardichvili, Alexandre A.; Jondle, Douglas J.; Mitchell, James A.

2008-01-01

403

Voltage/temperature charge characteristics  

NASA Technical Reports Server (NTRS)

A series of nickel cadmium batteries were tested to determine the effects of boltages and various temperatures on the charge discharge ratios and the recharge percentage. It was concluded that the selection of a proper temperature should consider the satellite orbit characteristics, the cell operating characteristics, the battery operating temperature range, and the final taper charge current.

Betz, F. E.

1978-01-01

404

The Valuation of Forest Characteristics  

Microsoft Academic Search

Most work on valuing the recreational benefits of public forests has concentrated on arriving at consumers surplus per visit figures, using either the travel cost method, or contingent valuation. We use both methods to try and explain the variation in consumers surplus across different forest types, by placing values on the physical characteristics of individual forests. These characteristics are also

Nick Hanley; Robin Ruffell

1992-01-01

405

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

406

Measurement of perceived task characteristics  

Microsoft Academic Search

Reviews studies examining 6 psychometric properties (e.g., internal consistency and reliability, convergent validity, and substantive validity) of 2 frequently used measures of perceived task characteristics––the Job Diagnostic Survey and the Job Characteristic Inventory. The evidence provides some support for the theoretical assumptions on which the scales are based, but it suggests serious difficulties as well. Alternative approaches to measurement of

Ramon J. Aldag; Steve H. Barr

1981-01-01

407

Backgrounds and characteristics of arsonists  

Microsoft Academic Search

The aim of this study was to gain more insight in the backgrounds and characteristics of arsonists. For this, the psychiatric, psychological, personal, and criminal backgrounds of all arsonists (n=25), sentenced to forced treatment in the maximum security forensic hospital “De Kijvelanden”, were compared to the characteristics of a control group of patients (n=50), incarcerated at the same institution for

Wim Labree; Henk Nijman; Hjalmar van Marle; Eric Rassin

2010-01-01

408

CHARACTERISTICS OF FISH POPULATIONS IN  

E-print Network

CHARACTERISTICS OF FISH POPULATIONS IN UPPER MISSISSIPPI RIVER BACKWATER AREAS Manne Bio and Wildlife, John S. Gottschalk, Direct or CHARACTERISTICS OF FISH POPULATIONS IN UPPER MISSISSIPPI RIVER B 16 Ifercentage composition 16 Weight per acre 16 Comparison with other waters 20 Mississippi River

409

Time Entry and Time Entry Approvals  

E-print Network

Time Entry and Time Entry Approvals PS Version 8.8 Contents (Updated: October, 2004) Hourly Employee Time Entry..................................................................................02 The Hourly Time and Earning Page .......................................................................03

Oklahoma, University of

410

Time Entry and Time Entry Approvals  

E-print Network

Time Entry and Time Entry Approvals PS Version 9.0 Contents (Updated: September, 2007) Hourly Employee Time Entry..................................................................................02 The Hourly Time and Earning Page .......................................................................03

Oklahoma, University of

411

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. PMID:19619895

Yang, Suzanne; Kadouri, Alane; Revah-Levy, Anne; Mulvey, Edward P.; Falissard, Bruno

2009-01-01

412

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

413

High energy real-time imaging studies.  

National Technical Information Service (NTIS)

Performance characteristics of high energy real-time radiography (RTR) systems were optimized by interchanging components and varying optical coupling methods. Phosphor screens, fiber optic scintillation plates, monolithic high density glass scintillation...

J. J. Haskins, K. W. Dolan, D. E. Perkins, D. Rikard, D. J. Schneberk

1993-01-01

414

Time dependent seismic hazard  

NASA Astrophysics Data System (ADS)

Probabilistic seismic hazard is usually computed trough a homogeneous Poisson process that even though it is a time-independent process it is widely used for its very convenient properties. However, when a single fault is of concern and/or the time scale is different from that of the long term, time-dependent processes are required. In this paper, different time-dependent models are reviewed with working examples. In fact, the Paganica fault (in central Italy) has been considered to compute both the probability of occurrence of at least one event in the lifespan of the structure, as well as the seismic hazard expressed in terms of probability of exceedance of an intensity value in a given time frame causing the collapse of the structure. Several models, well known or novel application to engineering hazard have been considered, limitation and issues in their applications are also discussed. The Brownian Passage Time (BPT) model is based on a stochastic modification of the deterministic stick-slip oscillator model for characteristic earthquakes; i.e., based on the addition of random perturbations (a Gaussian white noise) to the deterministic load path predicted by elastic rebound theory. This model assumes that the load state is at some ground level immediately after an event, increases steadly over time, reaches a failure threshold and relaxes instantaneously back to the ground level. For this model also a variable threshold has been considered to take into account the uncertainty of the threshold value. For the slip-predictable model it is assumed that the stress accumulates at a constant rate starting from some initial stress level. Stress is assumed to accumulate for a random period of time until an earthquake occurs. The size of the earthquake is governed by the stress release and it is a function of the elapsed time since the last event. In the time-predictable model stress buildup occurs at a constant rate until the accumulated stress reaches a threshold; then an earthquake occurs and a part of the accumulated stress is released. The renewal gamma assumes that the loading in the source has to go under a fixed number of steps to trigger an event. Moreover, because these models are hardly capable to capture earthquake clustering, ETAS models have been also investigated. Finally, after-shock occurrence has been considered and modeled with a more traditional non-homogeneous Poisson process.

Polidoro, B.; Iervolino, I.; Chioccarelli, E.; Giorgio, M.

2012-04-01

415

14 CFR 27.239 - Spray characteristics.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Spray characteristics. 27.239 Section...Handling Characteristics § 27.239 Spray characteristics. If certification for water operation is requested, no spray characteristics during taxiing,...

2010-01-01

416

14 CFR 29.239 - Spray characteristics.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Spray characteristics. 29.239 Section...Handling Characteristics § 29.239 Spray characteristics. If certification for water operation is requested, no spray characteristics during taxiing,...

2010-01-01

417

40 CFR 261.24 - Toxicity characteristic.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Toxicity characteristic. 261.24 Section...Characteristics of Hazardous Waste § 261.24 Toxicity characteristic. (a) A solid waste...waste) exhibits the characteristic of toxicity if, using the Toxicity...

2010-07-01

418

Highly segmented, high resolution time-of-flight system  

SciTech Connect

The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

1991-12-31

419

Real-time flutter identification  

NASA Technical Reports Server (NTRS)

The techniques and a FORTRAN 77 MOdal Parameter IDentification (MOPID) computer program developed for identification of the frequencies and damping ratios of multiple flutter modes in real time are documented. Physically meaningful model parameterization was combined with state of the art recursive identification techniques and applied to the problem of real time flutter mode monitoring. The performance of the algorithm in terms of convergence speed and parameter estimation error is demonstrated for several simulated data cases, and the results of actual flight data analysis from two different vehicles are presented. It is indicated that the algorithm is capable of real time monitoring of aircraft flutter characteristics with a high degree of reliability.

Roy, R.; Walker, R.

1985-01-01

420

Rainfall characteristics along mountainous transect  

NASA Astrophysics Data System (ADS)

The HYdrological cycle in Mediterranean EXperiment is an experiment framework that aims at improving our understanding and quantification of processes related to the hydrological cycle in the Mediterranean region at different scales (from the individual event scale to seasonal and inter-annual variability). During the Special Observation Period (SOP-1) conducted from September 5th to November 6th 2012, an important and complementary remote sensing network (operational radars, X band research radars, Micro Rain Radars, disdrometers, and a dense network of rain gauges) has been deployed in the Cévennes-Vivarais region (South of France). This network was specifically designed to investigate the structure and the heterogeneity of precipitations as well as, in particular, the impact of orography on this structure and it has provided us with high resolution data (time and space) along strong topographic gradients (small hills, foothills and mountain). Hence, these data will support our research to precisely describe the precipitation systems and their structures over a complex terrain. In this work, we will describe the characteristics of rainfall along two topographic gradients based on the major events observed during the fall 2012 campaign period. A classification according to the type of precipitation (convective, stratiform and orographic) which can affect the region has been made to investigate orographic impact under different rainfall regimes. We will also examine the influence of the relief on the vertical and horizontal structure of precipitation. In particular, we will illustrate the modification of the drop size distribution toward smaller droplets as we go from the small hills to the mountains.

Zwiebel, Jimmy; Van Baelen, Joël; Anquetin, Sandrine; Pointin, Yves; Boudevillain, Brice

2014-05-01

421

Characteristics of in-air thermoplastic recording.  

PubMed

Concepts and characteristics of in-air thermoplastic recording are reviewed. The in-air method of electrophotographic recording relies upon a gaseous discharge of air molecules to form a latent charge pattern in the likeness of the image. Modulation is achieved with a light sensitive photoreceptor, and images are stored as surface deformations on the thermoplastic film. Development is instantaneous with heat, projection by schlieren optics, and erasure by melting the thermoplastic. The technique has been applied to (1) document type recording, where the entire image appears simultaneously, and (2) the recording of charactron type CRT images, where the information appears as a rapid short-time sequence of high intensity alphanumeric symbols. Problem areas are studied with the aid of the equivalent circuit and its transient analysis. Resolution, reciprocity, photoconductor characteristics, reusability, image sampling, and the effects of humidity are discussed. PMID:20076115

D'Antonio, N F

1969-01-01

422

Measuring spatial variability in soil characteristics  

SciTech Connect

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

423

Estimating the latent time of fault detection in finite automaton tested in real time  

Microsoft Academic Search

The notions of potential and real latent times of fault detection in finite automata were introduced. The potential latent\\u000a time is the minimal theoretical time of automaton fault detection, the real time is defined as the time of fault manifestation\\u000a at a certain point. A method for determination of the statistical characteristics of both times for the automaton tested in

R. Goot; I. Levin

2008-01-01

424

Practicing school psychologists: Their characteristics, activities, and populations served  

Microsoft Academic Search

Administered the National School Psychology Questionnaire, which was developed for the present study, to a nationwide, random sample of 877 school psychologists. The measure was designed to assess demographic characteristics, actual and desired activities, and actual and desired amount of time spent with various student groups. Results indicate that the majority of time was spent in assessment (54%), followed by

Douglas K. Smith

1984-01-01

425

Driving force characteristic under different Land use ways slope  

Microsoft Academic Search

Analyzed the erosion characteristic on different rainfall and different underlying horizon in base of yellow river institute of hydraulic re- search at 2008. The date shows: the soil erosion amount of bare slope and arable slope is 100 times that of grass slope; the steady soil erosion amount of small rainfall is 1\\/4 times that of middle rainfall and is

Zhenzhou Shen; Wenyi Yao; Zhanbin Li; Peiqing Xiao; Mian Li; Jishan Yang

2011-01-01

426

Investigation of dynamic characteristics of a turbine-propeller engine  

NASA Technical Reports Server (NTRS)

Time constants that characterize engine speed response of a turbine-propeller engine over the cruising speed range for various values of constant fuel flow and constant blade angle were obtained both from steady-state characteristics and from transient operation. Magnitude of speed response to changes in fuel flow and blade angle was investigated and is presented in the form of gain factors. Results indicate that at any given value of speed in the engine cruising speed range, time constants obtained both from steady-state characteristics and from transient operation agree satisfactorily for any given constant fuel flow, whereas time constants obtained from transient operation exceed time constants obtained from steady-state characteristics by approximately 14 percent for any given blade angle.

Oppenheimer, Frank L; Jacques, James R

1951-01-01

427

Characteristics of in Higher Education  

E-print Network

Characteristics of EXCELLENCE in Higher Education Requirements of Affiliation and Standards Education #12;Published by the Middle States Commission on Higher Education 3624 Market Street Philadelphia States Commission on Higher Education Twelfth edition All rights reserved. Previous editions of Standards

Aronov, Boris

428

Original article Chlorophyll fluorescence characteristics,  

E-print Network

Original article Chlorophyll fluorescence characteristics, performance and survival of freshly was eval- uated in situ using determinations of chlorophyll fluorescence and plant water status. Pre growth potential (RGP), root electrolyte leakage (REL), shoot water content and chlorophyll fluorescence

Boyer, Edmond

429

Time Management Managing Time and Tasks  

E-print Network

hours, normal sleep/wake times, meals, exercise, standing appointments, commuting time, social and do them together. 9. Limit your time checking e-mail or social media. 10. Perfectionism can't always commitments. The hours that are left are your `free time' ­ study time, unscheduled down time, time left open

Kasman, Alex

430

SPACE-TIME--TIME Homer G. Ellis  

E-print Network

SPACE-TIME--TIME Homer G. Ellis Abstract. Space-time--time is a natural hybrid of Kaluza's #12;ve-dimensional geometry and Weyl's conformal space-time geometry. Translations along the secondary time dimension pro" and is applicable to metrics of all dimensionalities and signatures. The de Sitter space-time metric

Ellis, Homer

431

Actions, behaviors, and characteristics of RNs involved in compensable injury.  

PubMed

Malpractice claims analysis offers valuable insight into nursing practice. A review of 16 malpractice claims involving 19 RNs identified their characteristics, actions, and behaviors that contributed to monetary compensation. Most events involved failure to perform a timely assessment and intervention. Relationships were found among nurses' characteristics and the severity of patient injury. Malpractice claims analysis affords nursing leaders the opportunity to involve RNs in correcting deficiencies that contribute to practice errors. PMID:21084889

Painter, Lisa M; Dudjak, Linda A

2010-12-01

432

Dynamic Characteristics at the Interface of Underwater Round Gas Jets  

Microsoft Academic Search

The gas-liquid interface characteristics of round gas-jets submerged in water was studied across a wide range of Mach numbers (0.4-1.9). High speed shadowphotography was used to image the gas jet and the interface was tracked from the digital images for all points in space and time. The results show how the interface characteristics are governed by buoyancy to momentum driven

Chris Weiland; Pavlos Vlachos

2009-01-01

433

IRRADIATION EFFECTS ON THE PHYSICAL CHARACTERISTICS OF SEWAGE SLUDGE  

SciTech Connect

The radiation effects on the physical characteristic of the sewage sludge were studied in order to obtain information which will be used for study on the enhancement of the sludge's dewaterability. Water contents, capillary suction time, zeta potential, irradiation dose, sludge acidity, total solid concentration, sludge particle size and microbiology before and after irradiation were investigated. Irradiation gave an effect on physical characteristics sludge. Water content in sludge cake could be reduced by irradiation at the dose of 10kGy.

Lee, M-J.; Lee, J-K.; Yoo, D-H.; Ho, K.

2004-10-05

434

Financial characteristics of hospitals purchased by investor-owned chains.  

PubMed

This article focuses on the preacquisition financial condition of not-for-profit hospitals acquired by investor-owned hospital chains. Financial ratios are used to determine if not-for-profit hospitals acquired by investor-owned hospital systems have common financial characteristics which make them a likely target for a takeover. The results indicate that during the time period studied, investor-owned hospital systems did tend to purchase hospitals with common financial characteristics and that these characteristics provide a reasonable description of a financially distressed hospital. This finding has important consequences for our health care delivery system. PMID:3771232

McCue, M J; Furst, R W

1986-10-01

435

Operating characteristics of a 2. 0-MeV RFQ  

SciTech Connect

A second radio-frequency quadrupole (RFQ) accelerator has been designed, constructed and operated at Los Alamos National Laboratory. The accelerator's design parameters represent a major extension from the original Los Alamos RFQ, with the new accelerator being 2.5 times as long, having three times the output energy, and with 2.5 times the current limit. The new accelerator's operating characteristics were studied for 3 months before disassembly to incorporate design mofidications. Results are discussed.

Purser, F.O.; Wadlinger, E.A.; Sander, O.R.; Potter, J.M.; Crandall, K.R.

1983-01-01

436

Time Warp Invariance by Recoding Time Delays into Time Delays  

E-print Network

Time Warp Invariance by Recoding Time Delays into Time Delays David J.C. MacKay University of Cambridge March 20th, 1996 Abstract A little investigation of how easy it is to get time warp invariance using your trick of coupling a decaying response g(t) to a time advance associated with a subthreshold

MacKay, David J.C.

437

Identity verification by keystroke timing  

E-print Network

dynamic setting. Unlike most static identity verification systems in use today, a verifier based on dynamic keystroke characteristics can monitor an individual's identity as he is working, instead of only at login time. This is accomplished by using... an imposter [Brand and Makey 1985; Cole 1978; National Bureau of Standards 1977; Warfel 1984]. The identification of a valid user can be based on any of three things: 1) Something the user knows (eg. passwords) 2) Something the user has (eg. keys) 3...

Usnick, Mark C.

2012-06-07

438

Emission Time Constant of Exoelectron and Formative Delay Time Analyzed by Using Discharge Probability Distribution  

Microsoft Academic Search

A discharge probability model is proposed to analyze the stochastic distribution of the discharge delay time. The distribution is described as a hybrid function between the exponential and Gaussian distributions and their characteristic properties, such as the emission time constant of an exoelectron and the average and standard deviations of the formative delay time. The calculated results of the probability

Shirun Ho; Norihiro Uemura; Shunichiro Nobuki; Shunsuke Mori; Tatsuya Miyake; Keizo Suzuki; Yoshiro Mikami; Masatoshi Shiiki; Shoichi Kubo

2010-01-01

439

Timing of cyber conflict.  

PubMed

Nations are accumulating cyber resources in the form of stockpiles of zero-day exploits as well as other novel methods of engaging in future cyber conflict against selected targets. This paper analyzes the optimal timing for the use of such cyber resources. A simple mathematical model is offered to clarify how the timing of such a choice can depend on the stakes involved in the present situation, as well as the characteristics of the resource for exploitation. The model deals with the question of when the resource should be used given that its use today may well prevent it from being available for use later. The analysis provides concepts, theory, applications, and distinctions to promote the understanding strategy aspects of cyber conflict. Case studies include the Stuxnet attack on Iran's nuclear program, the Iranian cyber attack on the energy firm Saudi Aramco, the persistent cyber espionage carried out by the Chinese military, and an analogous case of economic coercion by China in a dispute with Japan. The effects of the rapidly expanding market for zero-day exploits are also analyzed. The goal of the paper is to promote the understanding of this domain of cyber conflict to mitigate the harm it can do, and harness the capabilities it can provide. PMID:24474752

Axelrod, Robert; Iliev, Rumen

2014-01-28

440

Performance characteristics of the Mayo/IBM PACS  

NASA Astrophysics Data System (ADS)

The Mayo Clinic and IBM (at Rochester, Minnesota) have jointly developed a picture archiving system for use with Mayo's MRI and Neuro CT imaging modalities. The communications backbone of the PACS is a portion of the Mayo institutional network: a series of 4-Mbps token rings interconnected by bridges and fiber optic extensions. The performance characteristics of this system are important to understand because they affect the response time a PACS user can expect, and the response time for non-PACS users competing for resources on the institutional network. The performance characteristics of each component and the average load levels of the network were measured for various load distributions. These data were used to quantify the response characteristics of the existing system and to tune a model developed by North Dakota State University Department of Computer Science for predicting response times of more complex topologies.

Persons, Kenneth R.; Gehring, Dale G.; Pavicic, Mark J.; Ding, Yingjai

1991-07-01

441

Journal of Geophysical Research Publications: Community Characteristics  

NASA Astrophysics Data System (ADS)

Do earth science publications differ by subfield or gender? To figure this out we analyzed publications in JGR Atmosphere, Oceans, and Solid Earth for the year 2000. We assumed that the first author exerted controlling influence over publication characteristics and then we looked at the number of co-authors, number of institutions represented by co-author affiliations, page length of the article, number of references cited, number of subject categories represented in the cited references, number of times the article was cited, and the time between the date the article was submitted and the date when it was accepted for publication. We found that, within each field, there was remarkable similarity between the publications led by women and those led by men. Interesting differences showed up between subfields: for example, Solid Earth authors use more references than do authors publishing in Atmosphere or Oceans.

Pfirman, S. L.; Porter, A.

2009-12-01

442

Microrhythmic characteristics of musical instrument initial transients  

NASA Astrophysics Data System (ADS)

A microrhythmic analysis of initial transients of the violin, the guitar, the saxophone, the clarinet, and percussion instruments has been performed. They show characteristic patterns between instrument families, concerning the derivation of microrhythmic intervals within the tonal frequency range compared to psychoacoustic discrimination tasks by listeners. Microrhythm here is defined as the temporal distance between two amplitude peaks. As initial transients are a crucial part of the sound in terms of identification of instruments and the initial is just in the range of the second integration time of the ear, where frequency components can just be identified, these microrhythmic patterns could be a possibility for listeners to identify the instrument families. This is because microrhythmic intervals are instantaneously present and do not need an integration time span.

Bader, Rolf

2005-04-01

443

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

444

Brand Appearances on Prime-Time Television  

Microsoft Academic Search

This research provides a baseline study documenting the frequency, context and portrayal characteristics of brands appearing on prime-time television. One week of prime-time television on four major networks was used. A content analysis, using a coding scheme developed by Gupta and Lord (1998), was performed that captured the nature of brand portrayal in programs suitable for subtle persuasion. Results indicate

Rosellina Ferraro; Rosemary J. Avery

2000-01-01

445

Trend assessment of water quality time series  

Microsoft Academic Search

A general methodology is described for identifying and statistically modeling trends which may be contained in water quality time series. A range of useful exploratory data analysis tools are suggested for discovering important patterns and statistical characteristics of the data such as trends caused by external interventions. To estimate the entries in an evenly spaced time series when data are

A. Ian McLeod; Keith W. Hipel; Fernando Comancho

1983-01-01