Adiabatic sweep pulses for earth's field NMR with a surface coil

Science.gov (United States)

Conradi, Mark S.; Altobelli, Stephen A.; Sowko, Nicholas J.; Conradi, Susan H.; Fukushima, Eiichi

2018-03-01

Adiabatic NMR sweep pulses are described for inversion and excitation in very low magnetic fields B0 and with broad distribution of excitation field amplitude B1. Two aspects distinguish the low field case: (1) when B1 is comparable to or greater than B0, the rotating field approximation fails and (2) inversion sweeps cannot extend to values well below the Larmor frequency because they would approach or pass through zero frequency. Three approaches to inversion are described. The first is a conventional tangent frequency sweep down to the Larmor frequency, a 180° phase shift, and a sweep back up to the starting frequency. The other two are combined frequency and amplitude sweeps covering a narrower frequency range; one is a symmetric sweep from above to below the Larmor frequency and the other uses a smooth decrease of B1 immediately before and after the 180° phase shift. These two AM/FM sweeps show excellent inversion efficiencies over a wide range of B1, a factor of 30 or more. We also demonstrate an excitation sweep that works well in the presence of the same wide range of B1. We show that the primary effect of the counter-rotating field (i.e., at low B0) is that the magnetization suffers large, periodic deviations from where it would be at large B0. Thus, successful sweep pulses must avoid any sharp features in the amplitude, phase, or frequency.

A Compositional Sweep-Line State Space Exploration Method

DEFF Research Database (Denmark)

Kristensen, Lars Michael; Mailund, Thomas

2002-01-01

State space exploration is a main approach to verification of finite-state systems. The sweep-line method exploits a certain kind of progress present in many systems to reduce peak memory usage during state space exploration. We present a new sweep-line algorithm for a compositional setting where...

Automatic sweep circuit

International Nuclear Information System (INIS)

Keefe, D.J.

1980-01-01

An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input is described. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found

A Generalised Sweep-Line Method for Safety Properties

DEFF Research Database (Denmark)

Mailund; Kristensen, Lars Michael

2002-01-01

The recently developed sweep-line method exploits progress present in many concurrent systems to explore the full state space of the system while storing only small fragments of the state space in memory at a time. A disadvantage of the sweep-line method is that it relies on a monotone and global...

Automatically sweeping dual-channel boxcar integrator

International Nuclear Information System (INIS)

Keefe, D.J.; Patterson, D.R.

1978-01-01

An automatically sweeping dual-channel boxcar integrator has been developed to automate the search for a signal that repeatedly follows a trigger pulse by a constant or slowly varying time delay when that signal is completely hidden in random electrical noise and dc-offset drifts. The automatically sweeping dual-channel boxcar integrator improves the signal-to-noise ratio and eliminates dc-drift errors in the same way that a conventional dual-channel boxcar integrator does, but, in addition, automatically locates the hidden signal. When the signal is found, its time delay is displayed with 100-ns resolution, and its peak value is automatically measured and displayed. This relieves the operator of the tedious, time-consuming, and error-prone search for the signal whenever the time delay changes. The automatically sweeping boxcar integrator can also be used as a conventional dual-channel boxcar integrator. In either mode, it can repeatedly integrate a signal up to 990 times and thus make accurate measurements of the signal pulse height in the presence of random noise, dc offsets, and unsynchronized interfering signals

Southwest Energy Efficiency Project (SWEEP) Final Report

Energy Technology Data Exchange (ETDEWEB)

Geller, Howard [Southwest Energy Efficiency Project (SWEEP), Boulder, CO (United States); Meyers, Jim [Southwest Energy Efficiency Project (SWEEP), Boulder, CO (United States)

2018-01-29

SWEEP worked with Energy Efficiency and Renewable Energy (EERE) programs to foster greater energy efficiency throughout the Southwest. SWEEP accomplished this through a combination of analysis and support; preparation and distribution of materials on best practice technologies, policies and programs; and technical assistance and information dissemination to states and municipalities in the southwest supporting BTO, AMO, OWIP for advancement of efficiency in products and practices. These efforts were accomplished during the period 2012 through 2017.

Sweep devices for picosecond image-converter streak cameras

International Nuclear Information System (INIS)

Cunin, B.; Miehe, J.A.; Sipp, B.; Schelev, M.Ya.; Serduchenko, J.N.; Thebault, J.

1979-01-01

Four different sweep devices based on microwave tubes, avalanche transistors, krytrons, and laser-triggered spark gaps are treated in detail. These control circuits are developed for picosecond image-converter cameras and generate sweep pulses providing streak speeds in the range of 10 7 to 5x10 10 cm/sec with maximum time resolution better than 10 -12 sec. Special low-jitter triggering schemes reduce the jitter to less than 5x10 -11 sec. Some problems arising in the construction and matching of the sweep devices and image-streak tube are discussed. Comparative parameters of nanosecond switching elements are presented. The results described can be used by other authors involved in streak camera development

Development of sealing plug for sweep gas line

International Nuclear Information System (INIS)

Kikuchi, Taiji; Yamada, Hirokazu; Saitoh, Takashi; Nakamichi, Masaru; Tsuchiya, Kunihiko; Kawamura, Hiroshi

2004-03-01

On the irradiation capsule for neutron irradiation test of the tritium breeder, the sealing plug is necessary to prevent a leak of tritium gas when the tritium breeder is picked up from the irradiation capsule after irradiation test. However, the general valve and plug cannot apply to sealing of the sweep gas line because of the following factors, the neutron irradiation effect, limited space in the irradiation capsule, high sealing efficiency, simple method and operation for control. Therefore, the sealing plug for sweep gas line has to be developed. This paper reports the development of the sealing plug for sweep gas line and the operating procedure of the sealing plug in the irradiation capsule. (author)

Analysis of Massively Parallel Discrete-Ordinates Transport Sweep Algorithms with Collisions

International Nuclear Information System (INIS)

Bailey, T.S.; Falgout, R.D.

2008-01-01

We present theoretical scaling models for a variety of discrete-ordinates sweep algorithms. In these models, we pay particular attention to the way each algorithm handles collisions. A collision is defined as a processor having multiple angles with ready to be swept during one stage of the sweep. The models also take into account how subdomains are assigned to processors and how angles are grouped during the sweep. We describe a data driven algorithm that resolves collisions efficiently during the sweep as well as other algorithms that have been designed to avoid collisions completely. Our models are validated using the ARGES and AMTRAN transport codes. We then use the models to study and predict scaling trends in all of the sweep algorithms

Variability in the pre-transit signal of HD 189733 b

Science.gov (United States)

Cauley, Paul W.; Redfield, Seth; Jensen, Adam G.; Barman, Travis; Endl, Michael; Cochran, William D.

2016-01-01

Hot planets, i.e., those with orbital periods of a few days, can interact strongly with their host stars via gravitational tides, magnetic interactions, or via collisions between planetary and stellar winds or the planetary magnetosphere and the stellar wind. Recently, pre-transit absorption signals, caused by material orbiting ahead of the planet, have been detected around a handful of exoplanets. Two of these measurements, those for WASP-12 b (Llama et al. 2011) and HD 189733 b (Cauley et al. 2015), were interpreted as being the result of compressed material in a bow shock formed by the planetary magnetosphere plowing through the stellar wind. These signals are expected to be variable at some level as the planet passes through an inhomogenous stellar wind or corona and stellar activity levels change. To investigate this potential variability and confirm the detected signal, we have recently obtained followup observations to the 2013 transit reported in Cauley et al. (2015). The new measurements confirm the existence of the pre- and in-transit absorption detected in the 2013 data. However, the new signal is not consistent with the specific bow shock geometry presented in Cauley et al. (2015). We have performed a more detailed examination of the Ca II H and K line core flux, which is a proxy for the stellar activity level, for the 2013 data. We find a weak correlation between the Hα core flux and the Ca II core flux, suggesting that some, but not all, of the pre-transit absorption signature may be a result of changing stellar activity levels during the observations. Our examination of the Ca II core flux measurements uncover variability that is not seen using the SHK activity index. We are evaluating techniques to calibrate our Hα signal with these more detailed Ca II measurements and suggest that the core flux is a better proxy of low level stellar variability for a single epoch. In addition, the 2015 transit confirms that pre-transit absorption signals are

Design and optimization of a bend-and-sweep compliant mechanism

International Nuclear Information System (INIS)

Tummala, Y; Frecker, M I; Wissa, A A; Hubbard Jr, J E

2013-01-01

A novel contact aided compliant mechanism called bend-and-sweep compliant mechanism is presented in this paper. This mechanism has nonlinear stiffness properties in two orthogonal directions. An angled compliant joint (ACJ) is the fundamental element of this mechanism. Geometric parameters of ACJs determine the stiffness of the compliant mechanism. This paper presents the design and optimization of bend-and-sweep compliant mechanism. A multi-objective optimization problem was formulated for design optimization of the bend-and-sweep compliant mechanism. The objectives of the optimization problem were to maximize or minimize the bending and sweep displacements, depending on the situation, while minimizing the von Mises stress and mass of each mechanism. This optimization problem was solved using NSGA-II (a genetic algorithm). The results of this optimization for a single ACJ during upstroke and downstroke are presented in this paper. Results of two different loading conditions used during optimization of a single ACJ for upstroke are presented. Finally, optimization results comparing the performance of compliant mechanisms with one and two ACJs are also presented. It can be inferred from these results that the number of ACJs and the design of each ACJ determines the stiffness of the bend-and-sweep compliant mechanism. These mechanisms can be used in various applications. The goal of this research is to improve the performance of ornithopters by passively morphing their wings. In order to achieve a bio-inspired wing gait called continuous vortex gait, the wings of the ornithopter need to bend, and sweep simultaneously. This can be achieved by inserting the bend-and-sweep compliant mechanism into the leading edge wing spar of the ornithopters. (paper)

NOFI oil Vee-Sweep and extension boom test at OHMSETT

International Nuclear Information System (INIS)

Bitting, K.R.; Vicedomine, J.

1993-01-01

The NOFI Vee-Sweep is an inflatable oil collection boom held in a V configuration by cross netting attached to the skirt of the boom. The NOFI 600S is an inflatable oil boom used to divert oil into the Vee-Sweep. The lower section of the 600S skirt consists of a feather net and a ballast chain. The booms are designed for open-ocean skimming where a skimmer is placed in the Vee-Sweep apex to remove the collected oil. During testing, the booms were preloaded with oil and towed in the OHMSETT tank at various speeds and wave conditions. Each boom was tested for its first and gross (continuous) oil loss speeds. The Vee-Sweep was also evaluated for wave performance, oil thickness vs tow speed, oil loss rate, and critical tow speed. Finally, a DESMI-250 oil skimmer was placed in the Vee-Sweep apex and oil loss tests were run while the skimmer was operating. During the critical tow speed testing, failures occurred due to apex submergence at ca 3.5 knots in calm water and short-crested waves, and 2.4 knots in harbor chop. The oil loss tests showed that the Vee-Sweep retains oil at speeds significantly higher than conventional booms. First oil loss speeds ranged from 1.3 knots in calm water to 1.0 knot in regular waves. The Vee-Sweep's high buoyancy/weight ratio gave it good wave performance in all conditions tested. The 600S oil loss speeds were higher than those of most conventional booms, and performance was better when the feather net was attached. 1 ref., 4 figs., 4 tabs

Simulation of Sweep-Jet Flow Control, Single Jet and Full Vertical Tail

Science.gov (United States)

Childs, Robert E.; Stremel, Paul M.; Garcia, Joseph A.; Heineck, James T.; Kushner, Laura K.; Storms, Bruce L.

2016-01-01

This work is a simulation technology demonstrator, of sweep jet flow control used to suppress boundary layer separation and increase the maximum achievable load coefficients. A sweep jet is a discrete Coanda jet that oscillates in the plane parallel to an aerodynamic surface. It injects mass and momentum in the approximate streamwise direction. It also generates turbulent eddies at the oscillation frequency, which are typically large relative to the scales of boundary layer turbulence, and which augment mixing across the boundary layer to attack flow separation. Simulations of a fluidic oscillator, the sweep jet emerging from a nozzle downstream of the oscillator, and an array of sweep jets which suppresses boundary layer separation are performed. Simulation results are compared to data from a dedicated validation experiment of a single oscillator and its sweep jet, and from a wind tunnel test of a full-scale Boeing 757 vertical tail augmented with an array of sweep jets. A critical step in the work is the development of realistic time-dependent sweep jet inflow boundary conditions, derived from the results of the single-oscillator simulations, which create the sweep jets in the full-tail simulations. Simulations were performed using the computational fluid dynamics (CFD) solver Overow, with high-order spatial discretization and a range of turbulence modeling. Good results were obtained for all flows simulated, when suitable turbulence modeling was used.

Entropy change at the magnetostructural transition in RCo2(R=Dy,Ho,Er)

International Nuclear Information System (INIS)

Herrero-Albillos, J.; Bartolome, F.; Garcia, L.M.; Casanova, F.; Labarta, A.; Batlle, X.

2006-01-01

Differential scanning calorimetry under applied magnetic field has been used to characterize the magnetocaloric effect in ErCo 2 , HoCo 2 , and DyCo 2 . The entropy change ΔS at the first-order magnetostructural transition present in these materials has been studied by inducing the transition; sweeping the temperature at a constant field and sweeping the field at a constant temperature. The corresponding values of ΔS differ significantly due to the broadness of the transition, i.e. the initial and final states involved when the transition is field or temperature induced are different. In the field-induced case, the additional work done by the magnetic field extending through the region in which the transition spread accounts roughly for the observed difference

An Algorithm for Parallel Sn Sweeps on Unstructured Meshes

International Nuclear Information System (INIS)

Pautz, Shawn D.

2002-01-01

A new algorithm for performing parallel S n sweeps on unstructured meshes is developed. The algorithm uses a low-complexity list ordering heuristic to determine a sweep ordering on any partitioned mesh. For typical problems and with 'normal' mesh partitionings, nearly linear speedups on up to 126 processors are observed. This is an important and desirable result, since although analyses of structured meshes indicate that parallel sweeps will not scale with normal partitioning approaches, no severe asymptotic degradation in the parallel efficiency is observed with modest (≤100) levels of parallelism. This result is a fundamental step in the development of efficient parallel S n methods

Alternating direction transport sweeps for linear discontinuous SN method

International Nuclear Information System (INIS)

Yavuz, M.; Aykanat, C.

1993-01-01

The performance of Alternating Direction Transport Sweep (ADTS) method is investigated for spatially differenced Linear Discontinuous S N (LD-S N ) problems on a MIMD multicomputer, Intel IPSC/2. The method consists of dividing a transport problem spatially into sub-problems, assigning each sub-problem to a separate processor. Then, the problem is solved by performing transport sweeps iterating on the scattering source and interface fluxes between the sub-problems. In each processor, the order of transport sweeps is scheduled such that a processor completing its computation in a quadrant of a transport sweep is able to use the most recent information (exiting fluxes of neighboring processor) as its incoming fluxes to start the next quadrant calculation. Implementation of this method on the Intel IPSC/2 multicomputer displays significant speedups over the one-processor method. Also, the performance of the method is compared with those reported previously for the Diamond Differenced S N (DD-S N ) method. Our experimental experience illustrates that the parallel performance of both the ADTS LD- and DD-S N methods is the same. (orig.)

Signatures of soft sweeps across the Dt1 locus underlying determinate growth habit in soya bean [Glycine max (L.) Merr.].

Science.gov (United States)

Zhong, Limei; Yang, Qiaomei; Yan, Xin; Yu, Chao; Su, Liu; Zhang, Xifeng; Zhu, Youlin

2017-09-01

Determinate growth habit is an agronomically important trait associated with domestication in soya bean. Previous studies have demonstrated that the emergence of determinacy is correlated with artificial selection on four nonsynonymous mutations in the Dt1 gene. To better understand the signatures of the soft sweeps across the Dt1 locus and track the origins of the determinate alleles, we examined patterns of nucleotide variation in Dt1 and the surrounding genomic region of approximately 800 kb. Four local, asymmetrical hard sweeps on four determinate alleles, sized approximately 660, 120, 220 and 150 kb, were identified, which constitute the soft sweeps for the adaptation. These variable-sized sweeps substantially reflected the strength and timing of selection and indicated that the selection on the alleles had been completed rapidly within half a century. Statistics of EHH, iHS, H12 and H2/H1 based on haplotype data had the power to detect the soft sweeps, revealing distinct signatures of extensive long-range LD and haplotype homozygosity, and multiple frequent adaptive haplotypes. A haplotype network constructed for Dt1 and a phylogenetic tree based on its extended haplotype block implied independent sources of the adaptive alleles through de novo mutations or rare standing variation in quick succession during the selective phase, strongly supporting multiple origins of the determinacy. We propose that the adaptation of soya bean determinacy is guided by a model of soft sweeps and that this model might be indispensable during crop domestication or evolution. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Autonomous Planning and Replanning for Mine-Sweeping Unmanned Underwater Vehicles

Science.gov (United States)

Gaines, Daniel M.

2010-01-01

This software generates high-quality plans for carrying out mine-sweeping activities under resource constraints. The autonomous planning and replanning system for unmanned underwater vehicles (UUVs) takes as input a set of prioritized mine-sweep regions, and a specification of available UUV resources including available battery energy, data storage, and time available for accomplishing the mission. Mine-sweep areas vary in location, size of area to be swept, and importance of the region. The planner also works with a model of the UUV, as well as a model of the power consumption of the vehicle when idle and when moving.

Fast sweeping method for the factored eikonal equation

Science.gov (United States)

Fomel, Sergey; Luo, Songting; Zhao, Hongkai

2009-09-01

We develop a fast sweeping method for the factored eikonal equation. By decomposing the solution of a general eikonal equation as the product of two factors: the first factor is the solution to a simple eikonal equation (such as distance) or a previously computed solution to an approximate eikonal equation. The second factor is a necessary modification/correction. Appropriate discretization and a fast sweeping strategy are designed for the equation of the correction part. The key idea is to enforce the causality of the original eikonal equation during the Gauss-Seidel iterations. Using extensive numerical examples we demonstrate that (1) the convergence behavior of the fast sweeping method for the factored eikonal equation is the same as for the original eikonal equation, i.e., the number of iterations for the Gauss-Seidel iterations is independent of the mesh size, (2) the numerical solution from the factored eikonal equation is more accurate than the numerical solution directly computed from the original eikonal equation, especially for point sources.

Performance Comparison of Sweeping/Steady Jet Actuators

Science.gov (United States)

Hirsch, Damian; Mercier, Justin; Noca, Flavio; Gharib, Morteza

2015-11-01

Flow control through the use of steady jet actuators has been used on various aircraft models since the late 1950's. However, the focus of recent studies has shifted towards the use of sweeping jets (fluidic oscillators) rather than steady jet actuators. In this work, experiments using various jet actuator designs were conducted at GALCIT's Lucas Wind Tunnel on a NACA 0012 vertical tail model similar to that of the Boeing 767 vertical stabilizer at Reynolds numbers ranging from 0.5 to 1.2 million. The rudder angle was fixed at 20 degrees. A total of 32 jet actuators were installed along the wingspan perpendicular to the trailing edge and the rudder shoulder of the vertical stabilizer. It is known that these types of flow control prevent separation. However, the goal of this work is to compare different jet designs and evaluate their performance. Parameters such as the number of actuators, their volumetric flow, and the wind tunnel speed were varied. The lift generation capabilities of steady and sweeping jet actuators were then compared. Another set of experiments was conducted to compare a new sweeping jet actuator design with one of the standard versions. Supported by Boeing.

High-Fidelity Aerodynamic Design with Transition Prediction, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — To enhance aerodynamic design capabilities, Desktop Aeronautics proposes to combine a new sweep/taper integrated-boundary-layer (IBL) code that includes transition...

Analyser of sweeping electron beam

International Nuclear Information System (INIS)

Strasser, A.

1993-01-01

The electron beam analyser has an array of conductors that can be positioned in the field of the sweeping beam, an electronic signal treatment system for the analysis of the signals generated in the conductors by the incident electrons and a display for the different characteristics of the electron beam

Mitigation of divertor heat loads by strike point sweeping in high power JET discharges

Science.gov (United States)

Silburn, S. A.; Matthews, G. F.; Challis, C. D.; Frigione, D.; Graves, J. P.; Mantsinen, M. J.; Belonohy, E.; Hobirk, J.; Iglesias, D.; Keeling, D. L.; King, D.; Kirov, K.; Lennholm, M.; Lomas, P. J.; Moradi, S.; Sips, A. C. C.; Tsalas, M.; Contributors, JET

2017-12-01

Deliberate periodic movement (sweeping) of the high heat flux divertor strike lines in tokamak plasmas can be used to manage the heat fluxes experienced by exhaust handling plasma facing components, by spreading the heat loads over a larger surface area. Sweeping has recently been adopted as a routine part of the main high performance plasma configurations used on JET, and has enabled pulses with 30 MW plasma heating power and 10 MW radiation to run for 5 s without overheating the divertor tiles. We present analysis of the effectiveness of sweeping for divertor temperature control on JET, using infrared camera data and comparison with a simple 2D heat diffusion model. Around 50% reduction in tile temperature rise is obtained with 5.4 cm sweeping compared to the un-swept case, and the temperature reduction is found to scale slower than linearly with sweeping amplitude in both experiments and modelling. Compatibility of sweeping with high fusion performance is demonstrated, and effects of sweeping on the edge-localised mode behaviour of the plasma are reported and discussed. The prospects of using sweeping in future JET experiments with up to 40 MW heating power are investigated using a model validated against existing experimental data.

Mitigation of divertor heat loads by strike point sweeping in high power JET discharges

International Nuclear Information System (INIS)

Silburn, S A; Matthews, G F; Challis, C D; Belonohy, E; Iglesias, D; Keeling, D L; King, D; Kirov, K; Lomas, P J; Frigione, D; Graves, J P; Mantsinen, M J; Hobirk, J; Lennholm, M; Moradi, S; Sips, A C C; Tsalas, M

2017-01-01

Deliberate periodic movement (sweeping) of the high heat flux divertor strike lines in tokamak plasmas can be used to manage the heat fluxes experienced by exhaust handling plasma facing components, by spreading the heat loads over a larger surface area. Sweeping has recently been adopted as a routine part of the main high performance plasma configurations used on JET, and has enabled pulses with 30 MW plasma heating power and 10 MW radiation to run for 5 s without overheating the divertor tiles. We present analysis of the effectiveness of sweeping for divertor temperature control on JET, using infrared camera data and comparison with a simple 2D heat diffusion model. Around 50% reduction in tile temperature rise is obtained with 5.4 cm sweeping compared to the un-swept case, and the temperature reduction is found to scale slower than linearly with sweeping amplitude in both experiments and modelling. Compatibility of sweeping with high fusion performance is demonstrated, and effects of sweeping on the edge-localised mode behaviour of the plasma are reported and discussed. The prospects of using sweeping in future JET experiments with up to 40 MW heating power are investigated using a model validated against existing experimental data. (paper)

A new method for calculating volumetric sweeps efficiency using streamline simulation concepts

International Nuclear Information System (INIS)

Hidrobo, E A

2000-01-01

One of the purposes of reservoir engineering is to quantify the volumetric sweep efficiency for optimizing reservoir management decisions. The estimation of this parameter has always been a difficult task. Until now, sweep efficiency correlations and calculations have been limited to mostly homogeneous 2-D cases. Calculating volumetric sweep efficiency in a 3-D heterogeneous reservoir becomes difficult due to inherent complexity of multiple layers and arbitrary well configurations. In this paper, a new method for computing volumetric sweep efficiency for any arbitrary heterogeneity and well configuration is presented. The proposed method is based on Datta-Gupta and King's formulation of streamline time-of-flight (1995). Given the fact that the time-of-flight reflects the fluid front propagation at various times, then the connectivity in the time-of-flight represents a direct measure of the volumetric sweep efficiency. The proposed approach has been applied to synthetic as well as field examples. Synthetic examples are used to validate the volumetric sweep efficiency calculations using the streamline time-of-flight connectivity criterion by comparison with analytic solutions and published correlations. The field example, which illustrates the feasibility of the approach for large-scale field applications, is from the north Robertson unit, a low permeability carbonate reservoir in west Texas

Transition Achievement among Young Adults with Deafness: What Variables Relate to Success?

Science.gov (United States)

Bullis, Michael; And Others

1995-01-01

Examines the transition achievement of deaf persons 3 or 4 years out of high school (n=308). Ten independent variables were used to predict 2 dichotomous dependent variables: engagement with community (56%), and residential status (52% living independently). Results are presented for each dependent variable. (JPS)

Potential effects of structural controls and street sweeping on stormwater loads to the lower Charles River, Massachusetts

Science.gov (United States)

Zarriello, Phillip J.; Breault, Robert F.; Weiskel, Peter K.

2002-01-01

The water quality of the lower Charles River is periodically impaired by combined sewer overflows (CSOs) and non-CSO stormwater runoff. This study examined the potential non-CSO load reductions of suspended solids, fecal coliform bacteria, total phosphorus, and total lead that could reasonably be achieved by implementation of stormwater best management practices, including both structural controls and systematic street sweeping. Structural controls were grouped by major physical or chemical process; these included infiltration-filtration (physical separation), biofiltration-bioretention (biological mechanisms), or detention-retention (physical settling). For each of these categories, upper and lower quartiles, median, and average removal efficiencies were compiled from three national databases of structural control performance. Removal efficiencies obtained indicated a wide range of performance. Removal was generally greatest for infiltration-filtration controls and suspended solids, and least for biofiltration-bioretention controls and fecal coliform bacteria. Street sweeping has received renewed interest as a water-quality control practice because of reported improvements in sweeper technology and the recognition that opportunities for implementing structural controls are limited in highly urbanized areas. The Stormwater Management Model that was developed by the U.S. Geological Survey for the lower Charles River Watershed was modified to simulate the effects of street sweeping in a single-family land-use basin. Constituent buildup and washoff variable values were calibrated to observed annual and storm-event loads. Once calibrated, the street sweeping model was applied to various permutations of four sweeper efficiencies and six sweeping frequencies that ranged from every day to once every 30 days. Reduction of constituent loads to the lower Charles River by the combined hypothetical practices of structural controls and street sweeping was estimated for a range

Soft Sweeps Are the Dominant Mode of Adaptation in the Human Genome.

Science.gov (United States)

Schrider, Daniel R; Kern, Andrew D

2017-08-01

The degree to which adaptation in recent human evolution shapes genetic variation remains controversial. This is in part due to the limited evidence in humans for classic "hard selective sweeps", wherein a novel beneficial mutation rapidly sweeps through a population to fixation. However, positive selection may often proceed via "soft sweeps" acting on mutations already present within a population. Here, we examine recent positive selection across six human populations using a powerful machine learning approach that is sensitive to both hard and soft sweeps. We found evidence that soft sweeps are widespread and account for the vast majority of recent human adaptation. Surprisingly, our results also suggest that linked positive selection affects patterns of variation across much of the genome, and may increase the frequencies of deleterious mutations. Our results also reveal insights into the role of sexual selection, cancer risk, and central nervous system development in recent human evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Single-sweep spectral analysis of contact heat evoked potentials

DEFF Research Database (Denmark)

Hansen, Tine M; Graversen, Carina; Frøkjaer, Jens B

2015-01-01

AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single-sweep ch......AIMS: The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single...... by 13% (P = 0.04) and 9% (P = 0.007), while the beta and gamma bands were increased by 10% (P = 0.006) and 24% (P = 0.04). CONCLUSION: The decreases in the delta and theta band are suggested to represent a decrease in the pain specific morphology of the CHEPs, which indicates a diminished pain response...

A Sweeping Jet Application on a High Reynolds Number Semispan Supercritical Wing Configuration

Science.gov (United States)

Jones, Gregory S.; Milholen, William E., II; Chan, David T.; Melton, Latunia; Goodliff, Scott L.; Cagle, C. Mark

2017-01-01

The FAST-MAC circulation control model was modified to test an array of unsteady sweeping-jet actuators at realistic flight Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center. Two types of sweeping jet actuators were fabricated using rapid prototype techniques, and directed over a 15% chord simple-hinged flap. The model was configured for low-speed high-lift testing with flap deflections of 30 deg and 60 deg, and a transonic cruise configuration having a 0 deg flap deflection. For the 30 deg flap high-lift configuration, the sweeping jets achieved comparable lift performance in the separation control regime, while reducing the mass flow by 54% as compared to steady blowing. The sweeping jets however were not effective for the 60 deg flap. For the transonic cruise configuration, the sweeping jets reduced the drag by 3.3% at an off-design condition. The drag reduction for the design lift coefficient for the sweeping jets offer is only half the drag reduction shown for the steady blowing case (6.5%), but accomplished this with a 74% reduction in mass flow.

Acupuncture and/or sweeping of the fetal membranes before induction of labor

DEFF Research Database (Denmark)

Andersen, Bodil Birgitte; Knudsen, Birthe; Lyndrup, Jens

2013-01-01

To evaluate the efficacy of acupuncture, and sweeping of the fetal membranes, as methods for induction of labor.......To evaluate the efficacy of acupuncture, and sweeping of the fetal membranes, as methods for induction of labor....

Analysis of sweeping heat loads on divertor plate materials

International Nuclear Information System (INIS)

Hassanein, A.

1991-01-01

The heat flux on the divertor plate of a fusion reactor is probably one of the most limiting constraints on its lifetime. The current heat flux profile on the outer divertor plate of a device like ITER is highly peaked with narrow profile. The peak heat flux can be as high as 30--40 MW/m 2 with full width at half maximum (FWHM) is in the order of a few centimeters. Sweeping the separatrix along the divertor plate is one of the options proposed to reduce the thermomechanical effects of this highly peaked narrow profile distribution. The effectiveness of the sweeping process is investigated parametrically for various design values. The optimum sweeping parameters of a particular heat load will depend on the design of the divertor plate as well as on the profile of such a heat load. In general, moving a highly peaked heat load results in substantial reduction of the thermomechanical effects on the divertor plate. 3 refs., 8 figs

Second order evolution inclusions governed by sweeping process in Banach spaces

Directory of Open Access Journals (Sweden)

A. G. Ibrahim

2009-11-01

Full Text Available In this paper we prove two existence theorems concerning the existence of solutions for second order evolution inclusions governed by sweeping process with closed convex sets depending on time and state in Banach spaces. This work extends some recent existence theorems cncerning sweeping process from Hilbert spaces to Banach spaces.

R2d2 Drives Selfish Sweeps in the House Mouse.

Science.gov (United States)

Didion, John P; Morgan, Andrew P; Yadgary, Liran; Bell, Timothy A; McMullan, Rachel C; Ortiz de Solorzano, Lydia; Britton-Davidian, Janice; Bult, Carol J; Campbell, Karl J; Castiglia, Riccardo; Ching, Yung-Hao; Chunco, Amanda J; Crowley, James J; Chesler, Elissa J; Förster, Daniel W; French, John E; Gabriel, Sofia I; Gatti, Daniel M; Garland, Theodore; Giagia-Athanasopoulou, Eva B; Giménez, Mabel D; Grize, Sofia A; Gündüz, İslam; Holmes, Andrew; Hauffe, Heidi C; Herman, Jeremy S; Holt, James M; Hua, Kunjie; Jolley, Wesley J; Lindholm, Anna K; López-Fuster, María J; Mitsainas, George; da Luz Mathias, Maria; McMillan, Leonard; Ramalhinho, Maria da Graça Morgado; Rehermann, Barbara; Rosshart, Stephan P; Searle, Jeremy B; Shiao, Meng-Shin; Solano, Emanuela; Svenson, Karen L; Thomas-Laemont, Patricia; Threadgill, David W; Ventura, Jacint; Weinstock, George M; Pomp, Daniel; Churchill, Gary A; Pardo-Manuel de Villena, Fernando

2016-06-01

A selective sweep is the result of strong positive selection driving newly occurring or standing genetic variants to fixation, and can dramatically alter the pattern and distribution of allelic diversity in a population. Population-level sequencing data have enabled discoveries of selective sweeps associated with genes involved in recent adaptations in many species. In contrast, much debate but little evidence addresses whether "selfish" genes are capable of fixation-thereby leaving signatures identical to classical selective sweeps-despite being neutral or deleterious to organismal fitness. We previously described R2d2, a large copy-number variant that causes nonrandom segregation of mouse Chromosome 2 in females due to meiotic drive. Here we show population-genetic data consistent with a selfish sweep driven by alleles of R2d2 with high copy number (R2d2(HC)) in natural populations. We replicate this finding in multiple closed breeding populations from six outbred backgrounds segregating for R2d2 alleles. We find that R2d2(HC) rapidly increases in frequency, and in most cases becomes fixed in significantly fewer generations than can be explained by genetic drift. R2d2(HC) is also associated with significantly reduced litter sizes in heterozygous mothers, making it a true selfish allele. Our data provide direct evidence of populations actively undergoing selfish sweeps, and demonstrate that meiotic drive can rapidly alter the genomic landscape in favor of mutations with neutral or even negative effects on overall Darwinian fitness. Further study will reveal the incidence of selfish sweeps, and will elucidate the relative contributions of selfish genes, adaptation and genetic drift to evolution. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Sweep visually evoked potentials and visual findings in children with West syndrome.

Science.gov (United States)

de Freitas Dotto, Patrícia; Cavascan, Nívea Nunes; Berezovsky, Adriana; Sacai, Paula Yuri; Rocha, Daniel Martins; Pereira, Josenilson Martins; Salomão, Solange Rios

2014-03-01

West syndrome (WS) is a type of early childhood epilepsy characterized by progressive neurological development deterioration that includes vision. To demonstrate the clinical importance of grating visual acuity thresholds (GVA) measurement by sweep visually evoked potentials technique (sweep-VEP) as a reliable tool for evaluation of the visual cortex status in WS children. This is a retrospective study of the best-corrected binocular GVA and ophthalmological features of WS children referred for the Laboratory of Clinical Electrophysiology of Vision of UNIFESP from 1998 to 2012 (Committee on Ethics in Research of UNIFESP n° 0349/08). The GVA deficit was calculated by subtracting binocular GVA score (logMAR units) of each patient from the median values of age norms from our own lab and classified as mild (0.1-0.39 logMAR), moderate (0.40-0.80 logMAR) or severe (>0.81 logMAR). Associated ophthalmological features were also described. Data from 30 WS children (age from 6 to 108 months, median = 14.5 months, mean ± SD = 22.0 ± 22.1 months; 19 male) were analyzed. The majority presented severe GVA deficit (0.15-1.44 logMAR; mean ± SD = 0.82 ± 0.32 logMAR; median = 0.82 logMAR), poor visual behavior, high prevalence of strabismus and great variability in ocular positioning. The GVA deficit did not vary according to gender (P = .8022), WS type (P = .908), birth age (P = .2881), perinatal oxygenation (P = .7692), visual behavior (P = .8789), ocular motility (P = .1821), nystagmus (P = .2868), risk of drug-induced retinopathy (P = .4632) and participation in early visual stimulation therapy (P = .9010). The sweep-VEP technique is a reliable tool to classify visual system impairment in WS children, in agreement with the poor visual behavior exhibited by them. Copyright © 2013 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Oxide vapor distribution from a high-frequency sweep e-beam system

Science.gov (United States)

Chow, R.; Tassano, P. L.; Tsujimoto, N.

1995-03-01

Oxide vapor distributions have been determined as a function of operating parameters of a high frequency sweep e-beam source combined with a programmable sweep controller. We will show which parameters are significant, the parameters that yield the broadest oxide deposition distribution, and the procedure used to arrive at these conclusions. A design-of-experimental strategy was used with five operating parameters: evaporation rate, sweep speed, sweep pattern (pre-programmed), phase speed (azimuthal rotation of the pattern), profile (dwell time as a function of radial position). A design was chosen that would show which of the parameters and parameter pairs have a statistically significant effect on the vapor distribution. Witness flats were placed symmetrically across a 25 inches diameter platen. The stationary platen was centered 24 inches above the e-gun crucible. An oxide material was evaporated under 27 different conditions. Thickness measurements were made with a stylus profilometer. The information will enable users of the high frequency e-gun systems to optimally locate the source in a vacuum system and understand which parameters have a major effect on the vapor distribution.

Integral definition of transition time in the Landau-Zener model

International Nuclear Information System (INIS)

Yan Yue; Wu Biao

2010-01-01

We give a general definition for the transition time in the Landau-Zener model. This definition allows us to compute numerically the Landau-Zener transition time at any sweeping rate without ambiguity in both diabatic and adiabatic bases. With this new definition, analytical results are obtained in both the adiabatic limit and the sudden limit.

Hybrid massively parallel fast sweeping method for static Hamilton–Jacobi equations

Energy Technology Data Exchange (ETDEWEB)

Detrixhe, Miles, E-mail: mdetrixhe@engineering.ucsb.edu [Department of Mechanical Engineering (United States); University of California Santa Barbara, Santa Barbara, CA, 93106 (United States); Gibou, Frédéric, E-mail: fgibou@engineering.ucsb.edu [Department of Mechanical Engineering (United States); University of California Santa Barbara, Santa Barbara, CA, 93106 (United States); Department of Computer Science (United States); Department of Mathematics (United States)

2016-10-01

The fast sweeping method is a popular algorithm for solving a variety of static Hamilton–Jacobi equations. Fast sweeping algorithms for parallel computing have been developed, but are severely limited. In this work, we present a multilevel, hybrid parallel algorithm that combines the desirable traits of two distinct parallel methods. The fine and coarse grained components of the algorithm take advantage of heterogeneous computer architecture common in high performance computing facilities. We present the algorithm and demonstrate its effectiveness on a set of example problems including optimal control, dynamic games, and seismic wave propagation. We give results for convergence, parallel scaling, and show state-of-the-art speedup values for the fast sweeping method.

Hybrid massively parallel fast sweeping method for static Hamilton–Jacobi equations

International Nuclear Information System (INIS)

Detrixhe, Miles; Gibou, Frédéric

2016-01-01

The fast sweeping method is a popular algorithm for solving a variety of static Hamilton–Jacobi equations. Fast sweeping algorithms for parallel computing have been developed, but are severely limited. In this work, we present a multilevel, hybrid parallel algorithm that combines the desirable traits of two distinct parallel methods. The fine and coarse grained components of the algorithm take advantage of heterogeneous computer architecture common in high performance computing facilities. We present the algorithm and demonstrate its effectiveness on a set of example problems including optimal control, dynamic games, and seismic wave propagation. We give results for convergence, parallel scaling, and show state-of-the-art speedup values for the fast sweeping method.

Variants of Moreau's sweeping process

International Nuclear Information System (INIS)

Siddiqi, A.H.; Manchanda, P.

2001-07-01

In this paper we prove the existence and uniqueness of two variants of Moreau's sweeping process -u'(t) is an element of Nc (t) (u(t)), where in one variant we replace u(t) by u'(t) in the right-hand side of the inclusion and in the second variant u'(t) and u(t) are respectively replaced by u''(t) and u'(t). (author)

Evaluation of two sweeping methods for estimating the number of immature Aedes aegypti (Diptera: Culicidae in large containers

Directory of Open Access Journals (Sweden)

Margareth Regina Dibo

2013-07-01

Full Text Available Introduction Here, we evaluated sweeping methods used to estimate the number of immature Aedes aegypti in large containers. Methods III/IV instars and pupae at a 9:1 ratio were placed in three types of containers with, each one with three different water levels. Two sweeping methods were tested: water-surface sweeping and five-sweep netting. The data were analyzed using linear regression. Results The five-sweep netting technique was more suitable for drums and water-tanks, while the water-surface sweeping method provided the best results for swimming pools. Conclusions Both sweeping methods are useful tools in epidemiological surveillance programs for the control of Aedes aegypti.

Enhancing the mathematical properties of new haplotype homozygosity statistics for the detection of selective sweeps.

Science.gov (United States)

Garud, Nandita R; Rosenberg, Noah A

2015-06-01

Soft selective sweeps represent an important form of adaptation in which multiple haplotypes bearing adaptive alleles rise to high frequency. Most statistical methods for detecting selective sweeps from genetic polymorphism data, however, have focused on identifying hard selective sweeps in which a favored allele appears on a single haplotypic background; these methods might be underpowered to detect soft sweeps. Among exceptions is the set of haplotype homozygosity statistics introduced for the detection of soft sweeps by Garud et al. (2015). These statistics, examining frequencies of multiple haplotypes in relation to each other, include H12, a statistic designed to identify both hard and soft selective sweeps, and H2/H1, a statistic that conditional on high H12 values seeks to distinguish between hard and soft sweeps. A challenge in the use of H2/H1 is that its range depends on the associated value of H12, so that equal H2/H1 values might provide different levels of support for a soft sweep model at different values of H12. Here, we enhance the H12 and H2/H1 haplotype homozygosity statistics for selective sweep detection by deriving the upper bound on H2/H1 as a function of H12, thereby generating a statistic that normalizes H2/H1 to lie between 0 and 1. Through a reanalysis of resequencing data from inbred lines of Drosophila, we show that the enhanced statistic both strengthens interpretations obtained with the unnormalized statistic and leads to empirical insights that are less readily apparent without the normalization. Copyright © 2015 Elsevier Inc. All rights reserved.

A beam sweeping system for the Fermilab antiproton production target

International Nuclear Information System (INIS)

Bieniosek, F.M.

1993-08-01

In the Main Injector era beam intensities high enough to damage the antiproton production target will be available. In order to continue to operate with a tightly-focused primary beam spot on the target, and thus maintain yield, it will be necessary to spread the hot spot on the target by use of a beam sweeping system. This report summarizes the requirements for such a system, and addresses the issues involved in the design of a sweeping system

A SPITZER IRS STUDY OF INFRARED VARIABILITY IN TRANSITIONAL AND PRE-TRANSITIONAL DISKS AROUND T TAURI STARS

International Nuclear Information System (INIS)

Espaillat, C.; Furlan, E.; D'Alessio, P.; Sargent, B.; Muzerolle, J.; Nagel, E.; Calvet, N.; Watson, Dan M.

2011-01-01

We present a Spitzer IRS study of variability in 14 T Tauri stars in the Taurus and Chamaeleon star-forming regions. The sample is composed of transitional and pre-transitional objects which contain holes and gaps in their disks. We detect variability between 5 and 38 μm in all but two of our objects on timescales of 2-3 years. Most of the variability observed can be classified as seesaw behavior, whereby the emission at shorter wavelengths varies inversely with the emission at longer wavelengths. For many of the objects we can reasonably reproduce the observed variability using irradiated disk models, particularly by changing the height of the inner disk wall by ∼20%. When the inner wall is taller, the emission at the shorter wavelengths is higher since the inner wall dominates the emission at 2-8 μm. The taller inner wall casts a larger shadow on the outer disk wall, leading to less emission at wavelengths beyond 20 μm where the outer wall dominates. We discuss how the possible presence of planets in these disks could lead to warps that cause changes in the height of the inner wall. We also find that crystalline silicates are common in the outer disks of our objects and that in the four disks in the sample with the most crystalline silicates, variability on timescales of 1 week is present. In addition to explaining the infrared variability described above, planets can create shocks and collisions which can crystallize the dust and lead to short timescale variability.

Variability of Two Young L/T Transition Brown Dwarfs

Science.gov (United States)

Allers, Katelyn; Biller, Beth; Gallimore, Jack; Crossfield, Ian

2015-10-01

We propose for photometric monitoring observations of WISEP J004701.06+680352 (hereinafter W0047) and 2MASSWJ2244316+204343 (hereinafter 2M2244) using Spitzer/IRAC. Both objects are kinematically confirmed L7 members of the 150 Myr old AB Doradus moving group and show remarkable spectral similarity in both the near-IR and optical. The WoW survey found that L/T transition brown dwarfs having detected mid-IR variability are redder than the typical J - K color for their spectral type. A Cycle 11 exploration program (P.I. Metchev) is investigating the geometrical dependence of color and variability by expanding the original WoW sample. If inclination and J - K color are correlated (as predicted by Metchev et al.), then the spectral and photometric diversity seen across the L/T transition could be explained by geometry rather than diversity in atmospheric chemistry and dynamics. This would have wide ranging implications for the way we model cloud dissipation for brown dwarfs and extrasolar planets. Our proposed observations will provide an important test of the Metchev et al. prediction complementary to their Cycle 11 program. W0047 and 2M2244 are the same age, and have remarkably similar colors (J - K = 2.55 and 2.46 mags, respectively) and underlying spectra. Thus, if Metchev's prediction about the correlation of inclination and spectral morphology holds true, we would expect that W0047 and 2M2244 should have similar inclinations. However, the measured v sin(i) values for W0047 and 2M2244 are quite different. This difference in v sin(i) could be due to spin-axis inclination (with W0047 having a smaller i) or orbital period (with W0047 having a longer period), both of which we will determine from our proposed observations. This test is a unique opportunity, as there are no other free-floating L/T transition dwarfs known to be both coeval and spectrally similar. Our proposed observations will also extend the spectral type range for young objects surveyed for variability

HB-Line Dissolution of Glovebox Floor Sweepings

International Nuclear Information System (INIS)

Gray, J.H.

1998-02-01

Two candidate flowsheets for dissolving glovebox floor sweepings in the HB-Line Phase I geometrically favorable dissolver have been developed.Dissolving conditions tested and modified during the laboratory program were based on the current processing scheme for dissolving high-fired Pu-238 oxide in HB-Line. Subsequent adjustments made to the HB-Line flowsheet reflected differences in the dissolution behavior between high-fired Pu-238 oxide and the MgO sand/PuF 4 /PuO 2 mixture in glovebox floor sweepings. Although both candidate flowsheets involved two separate dissolving steps and resulted incomplete dissolution of all solids, the one selected for use in HB-Line will require fewer processing operations and resembles the initial flowsheet proposed for dissolving sand, slag, and crucible material in F-Canyon dissolvers. Complete dissolution of glovebox floor sweepings was accomplished in the laboratory by initially dissolving between 55 and 65 degree in a 14 molar nitric acid solution. Under these conditions, partial dissolution of PuF 4 and complete dissolution of PuO 2 and MgO sand were achieved in less than one hour. The presence of free fluoride in solution,uncomplexed by aluminum, was necessary for complete dissolution of the PuO 2 .The remaining PuF 4 dissolved following addition of aluminum nitrate nonahydrate (ANN) to complex the fluoride and heating between 75 and 85 degree C for an additional hour. Precipitation of magnesium and/or aluminum nitrates could occur before, during, and after transfer of product solutions. Both dilution and/or product solution temperature controls may be necessary to prevent precipitation of these salts. Corrosion of the dissolver should not be an issue during these dissolving operations. Corrosion is minimized when dissolving at 55-65 degree C for one to three hours at a maximum uncomplexed free fluoride concentration of 0.07 molar and by dissolving at 75-85 degree C at a one to one aluminum to fluoride mole ratio for another

Detection and reconstruction of freeform sweeps

KAUST Repository

Barton, Michael

2014-05-01

We study the difficult problem of deciding if parts of a freeform surface can be generated, or approximately generated, by the motion of a planar profile through space. While this task is basic for understanding the geometry of shapes as well as highly relevant for manufacturing and building construction, previous approaches were confined to special cases like kinematic surfaces or "moulding" surfaces. The general case remained unsolved so far. We approach this problem by a combination of local and global methods: curve analysis with regard to "movability", curve comparison by common substring search in curvature plots, an exhaustive search through all planar cuts enhanced by quick rejection procedures, the ordering of candidate profiles and finally, global optimization. The main applications of our method are digital reconstruction of CAD models exhibiting sweep patches, and aiding in manufacturing freeform surfaces by pointing out those parts which can be approximated by sweeps. © 2014 The Author(s) Computer Graphics Forum © 2014 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

Selective sweeps of mitochondrial DNA can drive the evolution of uniparental inheritance.

Science.gov (United States)

Christie, Joshua R; Beekman, Madeleine

2017-08-01

Although the uniparental (or maternal) inheritance of mitochondrial DNA (mtDNA) is widespread, the reasons for its evolution remain unclear. Two main hypotheses have been proposed: selection against individuals containing different mtDNAs (heteroplasmy) and selection against "selfish" mtDNA mutations. Recently, uniparental inheritance was shown to promote adaptive evolution in mtDNA, potentially providing a third hypothesis for its evolution. Here, we explore this hypothesis theoretically and ask if the accumulation of beneficial mutations provides a sufficient fitness advantage for uniparental inheritance to invade a population in which mtDNA is inherited biparentally. In a deterministic model, uniparental inheritance increases in frequency but cannot replace biparental inheritance if only a single beneficial mtDNA mutation sweeps through the population. When we allow successive selective sweeps of mtDNA, however, uniparental inheritance can replace biparental inheritance. Using a stochastic model, we show that a combination of selection and drift facilitates the fixation of uniparental inheritance (compared to a neutral trait) when there is only a single selective mtDNA sweep. When we consider multiple mtDNA sweeps in a stochastic model, uniparental inheritance becomes even more likely to replace biparental inheritance. Our findings thus suggest that selective sweeps of beneficial mtDNA haplotypes can drive the evolution of uniparental inheritance. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Threshold received sound pressure levels of single 1-2 kHz and 6-7 kHz up-sweeps and down-sweeps causing startle responses in a harbor porpoise (Phocoena phocoena)

NARCIS (Netherlands)

Kastelein, R.A.; Steen, N.; Gransier, R.; Wensveen, P.J.; Jong, C.A.F. de

2012-01-01

Mid-frequency and low-frequency sonar systems produce frequency-modulated sweeps which may affect harbor porpoises. To study the effect of sweeps on behavioral responses (specifically startle responses, which we define as sudden changes in swimming speed and/or direction), a harbor porpoise in a

Near-infrared Variability in the 2MASS Calibration Fields: A Search for Planetary Transit Candidates

Science.gov (United States)

Plavchan, Peter; Jura, M.; Kirkpatrick, J. Davy; Cutri, Roc M.; Gallagher, S. C.

2008-01-01

The Two Micron All Sky Survey (2MASS) photometric calibration observations cover approximately 6 square degrees on the sky in 35 'calibration fields,' each sampled in nominal photometric conditions between 562 and 3692 times during the 4 years of the 2MASS mission. We compile a catalog of variables from the calibration observations to search for M dwarfs transited by extrasolar planets. We present our methods for measuring periodic and nonperiodic flux variability. From 7554 sources with apparent K(sub s) magnitudes between 5.6 and 16.1, we identify 247 variables, including extragalactic variables and 23 periodic variables. We have discovered three M dwarf eclipsing systems, including two candidates for transiting extrasolar planets.

Application of the WEPS and SWEEP models to non-agricultural disturbed lands

Directory of Open Access Journals (Sweden)

J. Tatarko

2016-12-01

Full Text Available Wind erosion not only affects agricultural productivity but also soil, air, and water quality. Dust and specifically particulate matter ≤10 μm (PM-10 has adverse effects on respiratory health and also reduces visibility along roadways, resulting in auto accidents. The Wind Erosion Prediction System (WEPS was developed by the USDA-Agricultural Research Service to simulate wind erosion and provide for conservation planning on cultivated agricultural lands. A companion product, known as the Single-Event Wind Erosion Evaluation Program (SWEEP, has also been developed which consists of the stand-alone WEPS erosion submodel combined with a graphical interface to simulate soil loss from single (i.e., daily wind storm events. In addition to agricultural lands, wind driven dust emissions also occur from other anthropogenic sources such as construction sites, mined and reclaimed areas, landfills, and other disturbed lands. Although developed for agricultural fields, WEPS and SWEEP are useful tools for simulating erosion by wind for non-agricultural lands where typical agricultural practices are not employed. On disturbed lands, WEPS can be applied for simulating long-term (i.e., multi-year erosion control strategies. SWEEP on the other hand was developed specifically for disturbed lands and can simulate potential soil loss for site- and date-specific planned surface conditions and control practices. This paper presents novel applications of WEPS and SWEEP for developing erosion control strategies on non-agricultural disturbed lands. Erosion control planning with WEPS and SWEEP using water and other dust suppressants, wind barriers, straw mulch, re-vegetation, and other management practices is demonstrated herein through the use of comparative simulation scenarios. The scenarios confirm the efficacy of the WEPS and SWEEP models as valuable tools for supporting the design of erosion control plans for disturbed lands that are not only cost-effective but

Application of the WEPS and SWEEP models to non-agricultural disturbed lands.

Science.gov (United States)

Tatarko, J; van Donk, S J; Ascough, J C; Walker, D G

2016-12-01

Wind erosion not only affects agricultural productivity but also soil, air, and water quality. Dust and specifically particulate matter ≤10 μm (PM-10) has adverse effects on respiratory health and also reduces visibility along roadways, resulting in auto accidents. The Wind Erosion Prediction System (WEPS) was developed by the USDA-Agricultural Research Service to simulate wind erosion and provide for conservation planning on cultivated agricultural lands. A companion product, known as the Single-Event Wind Erosion Evaluation Program (SWEEP), has also been developed which consists of the stand-alone WEPS erosion submodel combined with a graphical interface to simulate soil loss from single (i.e., daily) wind storm events. In addition to agricultural lands, wind driven dust emissions also occur from other anthropogenic sources such as construction sites, mined and reclaimed areas, landfills, and other disturbed lands. Although developed for agricultural fields, WEPS and SWEEP are useful tools for simulating erosion by wind for non-agricultural lands where typical agricultural practices are not employed. On disturbed lands, WEPS can be applied for simulating long-term (i.e., multi-year) erosion control strategies. SWEEP on the other hand was developed specifically for disturbed lands and can simulate potential soil loss for site- and date-specific planned surface conditions and control practices. This paper presents novel applications of WEPS and SWEEP for developing erosion control strategies on non-agricultural disturbed lands. Erosion control planning with WEPS and SWEEP using water and other dust suppressants, wind barriers, straw mulch, re-vegetation, and other management practices is demonstrated herein through the use of comparative simulation scenarios. The scenarios confirm the efficacy of the WEPS and SWEEP models as valuable tools for supporting the design of erosion control plans for disturbed lands that are not only cost-effective but also incorporate

Single feature polymorphism (SFP-based selective sweep identification and association mapping of growth-related metabolic traits in Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Stitt Mark

2010-03-01

Full Text Available Abstract Background Natural accessions of Arabidopsis thaliana are characterized by a high level of phenotypic variation that can be used to investigate the extent and mode of selection on the primary metabolic traits. A collection of 54 A. thaliana natural accession-derived lines were subjected to deep genotyping through Single Feature Polymorphism (SFP detection via genomic DNA hybridization to Arabidopsis Tiling 1.0 Arrays for the detection of selective sweeps, and identification of associations between sweep regions and growth-related metabolic traits. Results A total of 1,072,557 high-quality SFPs were detected and indications for 3,943 deletions and 1,007 duplications were obtained. A significantly lower than expected SFP frequency was observed in protein-, rRNA-, and tRNA-coding regions and in non-repetitive intergenic regions, while pseudogenes, transposons, and non-coding RNA genes are enriched with SFPs. Gene families involved in plant defence or in signalling were identified as highly polymorphic, while several other families including transcription factors are depleted of SFPs. 198 significant associations between metabolic genes and 9 metabolic and growth-related phenotypic traits were detected with annotation hinting at the nature of the relationship. Five significant selective sweep regions were also detected of which one associated significantly with a metabolic trait. Conclusions We generated a high density polymorphism map for 54 A. thaliana accessions that highlights the variability of resistance genes across geographic ranges and used it to identify selective sweeps and associations between metabolic genes and metabolic phenotypes. Several associations show a clear biological relationship, while many remain requiring further investigation.

Investigation of the Hydrodynamics of Sweep Blade in Hi-Speed Axial Fuel Pump Impeller

Directory of Open Access Journals (Sweden)

Ran Tao

2013-01-01

Full Text Available Fuel pump is a crucial component in aircraft engine ignition system. For the hi-speed axial fuel pumps, rotating stall triggers vortex and affects the operation stability and security. Sweep blade is widely used to solve the stability problems in aerodynamics field. Investigation on the hydrodynamics was conducted in this study. Based on the typical straight blade pump, positive and negative sweep blade pumps were modeled. With the large eddy simulation method, CFD simulations were conducted to calculate and analyze the flow characteristics in the pump models. To verify the simulation, experiments were also launched on the hydraulic test rig. Results show that the vortex occurs at the suction surface of blade and gathers near the blade tip region. Positive sweep blade is effective to reduce the hydraulic losses by driving the stalled fluid into the mid-part of blade. By applying the positive sweep blade on the axial fuel pump, the instability operating region will be diminished. Adopting sweep blade provides an effective means for stability and security of axial fuel pumps.

Reduction of non-point source contaminants associated with road-deposited sediments by sweeping.

Science.gov (United States)

Kim, Do-Gun; Kang, Hee-Man; Ko, Seok-Oh

2017-09-19

Road-deposited sediments (RDS) on an expressway, residual RDS collected after sweeping, and RDS removed by means of sweeping were analyzed to evaluate the degree to which sweeping removed various non-point source contaminants. The total RDS load was 393.1 ± 80.3 kg/km and the RDS, residual RDS, and swept RDS were all highly polluted with organics, nutrients, and metals. Among the metals studied, Cu, Zn, Pb, Ni, Ca, and Fe were significantly enriched, and most of the contaminants were associated with particles within the size range from 63 μm to 2 mm. Sweeping reduced RDS and its associated contaminants by 33.3-49.1% on average. We also measured the biological oxygen demand (BOD) of RDS in the present work, representing to our knowledge the first time that this has been done; we found that RDS contains a significant amount of biodegradable organics and that the reduction of BOD by sweeping was higher than that of other contaminants. Significant correlations were found between the contaminants measured, indicating that the organics and the metals originated from both exhaust and non-exhaust particles. Meanwhile, the concentrations of Cu and Ni were higher in 63 μm-2 mm particles than in smaller particles, suggesting that some metals in RDS likely exist intrinsically in particles, rather than only as adsorbates on particle surfaces. Overall, the results in this study showed that sweeping to collect RDS can be a good alternative for reduction of contaminants in runoff.

Nonadiabatic exchange dynamics during adiabatic frequency sweeps.

Science.gov (United States)

Barbara, Thomas M

2016-04-01

A Bloch equation analysis that includes relaxation and exchange effects during an adiabatic frequency swept pulse is presented. For a large class of sweeps, relaxation can be incorporated using simple first order perturbation theory. For anisochronous exchange, new expressions are derived for exchange augmented rotating frame relaxation. For isochronous exchange between sites with distinct relaxation rate constants outside the extreme narrowing limit, simple criteria for adiabatic exchange are derived and demonstrate that frequency sweeps commonly in use may not be adiabatic with regard to exchange unless the exchange rates are much larger than the relaxation rates. Otherwise, accurate assessment of the sensitivity to exchange dynamics will require numerical integration of the rate equations. Examples of this situation are given for experimentally relevant parameters believed to hold for in-vivo tissue. These results are of significance in the study of exchange induced contrast in magnetic resonance imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

Using Computational Fluid Dynamics and Experiments to Design Sweeping Jets for High Reynolds Number Cruise Configurations

Science.gov (United States)

Jones, Gregory S.; Milholen, William E., II; Fell, Jared S.; Webb, Sandy R.; Cagle, C. Mark

2016-01-01

The application of a sweeping jet actuator to a circulation control system was initiated by a risk reduction series of experiments to optimize the authority of a single sweeping jet actuator. The sweeping jet design was integrated into the existing Fundamental Aerodynamic Subsonic Transonic- Modular Active Control (FAST-MAC) model by replacing the steady blowing system with an array of thirty-nine sweeping jet cartridges. A constant slot height to wing chord ratio was similar to the steady blowing configuration resulting in each actuator having a unique in size for the sweeping jet configuration. While this paper will describe the scaling and optimization of the actuators for future high Reynolds number applications, the major focus of this effort was to target the transonic flight regime by increasing the amplitude authority of the actuator. This was accomplished by modifying the diffuser of the sweeping jet actuator, and this paper highlights twelve different diffuser designs. The experimental portion of this work was completed in the NASA Langley National Transonic Facility.

The frequency and level of sweep in mixed hardwood saw logs in the eastern United States

Science.gov (United States)

Peter Hamner; Marshall S. White; Philip A. Araman

2007-01-01

Hardwood sawmills traditionally saw logs in a manner that either orients sawlines parallel to the log central axis (straight sawing) or the log surface (allowing for taper). Sweep is characterized as uniform curvature along the entire length of a log. For logs with sweep, lumber yield losses from straight and taper sawing increase with increasing levels of sweep. Curve...

Measurements of the eigenfunction of reversed shear Alfvén eigenmodes that sweep downward in frequency

International Nuclear Information System (INIS)

Heidbrink, W. W.; Austin, M. E.; Spong, D. A.; Tobias, B. J.; Van Zeeland, M. A.

2013-01-01

Reversed shear Alfvén eigenmodes (RSAEs) usually sweep upward in frequency when the minimum value of the safety factor q min decreases in time. On rare occasions, RSAEs sweep downward prior to the upward sweep. Electron cyclotron emission measurements show that the radial eigenfunction during the downsweeping phase is similar to the eigenfunction of normal, upsweeping RSAEs

On detecting incomplete soft or hard selective sweeps using haplotype structure

DEFF Research Database (Denmark)

Ferrer-Admetlla, Anna; Liang, Mason; Korneliussen, Thorfinn Sand

2014-01-01

We present a new haplotype-based statistic (nSL) for detecting both soft and hard sweeps in population genomic data from a single population. We compare our new method with classic single-population haplotype and site frequency spectrum (SFS)-based methods and show that it is more robust, particu......We present a new haplotype-based statistic (nSL) for detecting both soft and hard sweeps in population genomic data from a single population. We compare our new method with classic single-population haplotype and site frequency spectrum (SFS)-based methods and show that it is more robust......, particularly to recombination rate variation. However, all statistics show some sensitivity to the assumptions of the demographic model. Additionally, we show that nSL has at least as much power as other methods under a number of different selection scenarios, most notably in the cases of sweeps from standing...

Numerical simulation of incidence and sweep effects on delta wing vortex breakdown

Science.gov (United States)

Ekaterinaris, J. A.; Schiff, Lewis B.

1994-01-01

The structure of the vortical flowfield over delta wings at high angles of attack was investigated. Three-dimensional Navier-Stokes numerical simulations were carried out to predict the complex leeward-side flowfield characteristics, including leading-edge separation, secondary separation, and vortex breakdown. Flows over a 75- and a 63-deg sweep delta wing with sharp leading edges were investigated and compared with available experimental data. The effect of variation of circumferential grid resolution grid resolution in the vicinity of the wing leading edge on the accuracy of the solutions was addressed. Furthermore, the effect of turbulence modeling on the solutions was investigated. The effects of variation of angle of attack on the computed vortical flow structure for the 75-deg sweep delta wing were examined. At moderate angles of attack no vortex breakdown was observed. When a critical angle of attack was reached, bubble-type vortex breakdown was found. With further increase in angle of attack, a change from bubble-type breakdown to spiral-type vortex breakdown was predicted by the numerical solution. The effects of variation of sweep angle and freestream Mach number were addressed with the solutions on a 63-deg sweep delta wing.

Characterization of Residuals Collected from Street Sweeping Operations

Science.gov (United States)

2018-02-01

Street sweeping is a routine roadway maintenance activity conducted by the Virginia Department of Transportation (VDOT). It also provides an added benefit as a non-structural stormwater best management practice implemented by VDOT to meet total maxim...

Load consequences when sweeping blades - A case study of a 5 MW pitch controlled wind turbine

Energy Technology Data Exchange (ETDEWEB)

Verelst, D.R.S.; Larsen, Torben J.

2010-08-15

The generic 5 MW NREL wind turbine model is used in Risoe's aeroelastic simulator HAWC2 to investigate 120 different swept blade configurations (forward and backward sweep). Sensitivity for 2 different controllers is considered as well. Backward sweep results in a pitch to feather torsional moment of the blade, effectively reducing blade twist angles under increased loading. This behaviour results in decreased flap-wise fatigue and extreme loads, an increase for edge-wise fatigue loading and status quo or slight decrease in extreme loads (depending on the controller). Tower base and shaft-end bending moments are reduced as well. Forward sweep leads to an increase in angle of attack under loading. For a pitch controlled turbine this leads to an increase in fatigue and extreme loading in all cases. A controller inflicted instability is present for the more extreme forward swept cases. Due to the shape of considered sweep curves, an inherent and significant increase in torsional blade root bending moment is noted. A boomerang shaped sweep curve is proposed to counteract this problematic increased loading. Controller sensitivity shows that adding sweep affects some loadings differently. Power output is reduced for backward sweep since the blade twist is optimized as a rigid structure, ignoring the torsional deformations which for a swept blade can be significant. (author)

Effect of blade sweep on inlet flow in axial compressor cascades

Directory of Open Access Journals (Sweden)

Hao Chang

2015-02-01

Full Text Available This paper presents comparative numerical studies to investigate the effects of blade sweep on inlet flow in axial compressor cascades. A series of swept and straight cascades was modeled in order to obtain a general understanding of the inlet flow field that is induced by sweep. A computational fluid dynamics (CFD package was used to simulate the cascades and obtain the required three-dimensional (3D flow parameters. A circumferentially averaged method was introduced which provided the circumferential fluctuation (CF terms in the momentum equation. A program for data reduction was conducted to obtain a circumferentially averaged flow field. The influences of the inlet flow fields of the cascades were studied and spanwise distributions of each term in the momentum equation were analyzed. The results indicate that blade sweep does affect inlet radial equilibrium. The characteristic of radial fluid transfer is changed and thus influencing the axial velocity distributions. The inlet flow field varies mainly due to the combined effect of the radial pressure gradient and the CF component. The axial velocity varies consistently with the incidence variation induced by the sweep, as observed in the previous literature. In addition, factors that might influence the radial equilibrium such as blade camber angles, solidity and the effect of the distance from the leading edge are also taken into consideration and comparatively analyzed.

Sweep-twist adaptive rotor blade : final project report.

Energy Technology Data Exchange (ETDEWEB)

Ashwill, Thomas D.

2010-02-01

Knight & Carver was contracted by Sandia National Laboratories to develop a Sweep Twist Adaptive Rotor (STAR) blade that reduced operating loads, thereby allowing a larger, more productive rotor. The blade design used outer blade sweep to create twist coupling without angled fiber. Knight & Carver successfully designed, fabricated, tested and evaluated STAR prototype blades. Through laboratory and field tests, Knight & Carver showed the STAR blade met the engineering design criteria and economic goals for the program. A STAR prototype was successfully tested in Tehachapi during 2008 and a large data set was collected to support engineering and commercial development of the technology. This report documents the methodology used to develop the STAR blade design and reviews the approach used for laboratory and field testing. The effort demonstrated that STAR technology can provide significantly greater energy capture without higher operating loads on the turbine.

Sweep excitation with order tracking: A new tactic for beam crack analysis

Science.gov (United States)

Wei, Dongdong; Wang, KeSheng; Zhang, Mian; Zuo, Ming J.

2018-04-01

Crack detection in beams and beam-like structures is an important issue in industry and has attracted numerous investigations. A local crack leads to global system dynamics changes and produce non-linear vibration responses. Many researchers have studied these non-linearities for beam crack diagnosis. However, most reported methods are based on impact excitation and constant frequency excitation. Few studies have focused on crack detection through external sweep excitation which unleashes abundant dynamic characteristics of the system. Together with a signal resampling technique inspired by Computed Order Tracking, this paper utilize vibration responses under sweep excitations to diagnose crack status of beams. A data driven method for crack depth evaluation is proposed and window based harmonics extracting approaches are studied. The effectiveness of sweep excitation and the proposed method is experimentally validated.

Hidden measurements, hidden variables and the volume representation of transition probabilities

OpenAIRE

Oliynyk, Todd A.

2005-01-01

We construct, for any finite dimension $n$, a new hidden measurement model for quantum mechanics based on representing quantum transition probabilities by the volume of regions in projective Hilbert space. For $n=2$ our model is equivalent to the Aerts sphere model and serves as a generalization of it for dimensions $n \\geq 3$. We also show how to construct a hidden variables scheme based on hidden measurements and we discuss how joint distributions arise in our hidden variables scheme and th...

Michelson mode selector for spectral range stabilization in a self-sweeping fiber laser.

Science.gov (United States)

Tkachenko, A Yu; Vladimirskaya, A D; Lobach, I A; Kablukov, S I

2018-04-01

We report on spectral range stabilization in a self-sweeping laser by adding a narrowband fiber Bragg grating (FBG) to the output mirror in the Michelson configuration. The effects of FBG reflectivity and optical path difference in the Michelson interferometer on the laser spectral dynamics are investigated. Optimization of the interferometer allows us to demonstrate broadband (over 16 nm) self-sweeping operation and reduction of the start and stop wavelength fluctuations by two orders and one order of magnitude (∼100 and 15 times) for start and stop bounds, respectively (down to several picometers). The proposed approaches significantly improve quality of the spectral dynamics and facilitate application of the self-sweeping lasers.

Impacts of Interannual Variability in Biogenic VOC Emissions near Transitional Ozone Production Regimes

Science.gov (United States)

Geddes, J.

2017-12-01

Due to successful NOx emission controls, summertime ozone production chemistry in urban areas across North America is transitioning from VOC-limited to increasingly NOx-limited. In some regions where ozone production sensitivity is in transition, interannual variability in surrounding biogenic VOC emissions could drive fluctuations in the prevailing chemical regime and modify the impact of anthropogenic emission changes. I use satellite observations of HCHO and NO2 column density, along with a long-term simulation of atmospheric chemistry, to investigate the impact of interannual variability in biogenic isoprene sources near large metro areas. Peak emissions of isoprene in the model can vary by up to 20-60% in any given year compared to the long term mean, and this variability drives the majority of the variability in simulated local HCHO:NO2 ratios (a common proxy for ozone production sensitivity). The satellite observations confirm increasingly NOx-limited chemical regimes with large interannual variability. In several instances, the model and satellite observations suggest that variability in biogenic isoprene emissions could shift summertime ozone production from generally VOC- to generally NOx- sensitive (or vice versa). This would have implications for predicting the air quality impacts of anthropogenic emission changes in any given year, and suggests that drivers of biogenic emissions need to be well understood.

Solar Wind Earth Exchange Project (SWEEP)

Science.gov (United States)

2016-10-28

highly charged ions of the solar wind. The main challenge in predicting the resultant photon flux in the X-ray energy bands is due to the...Newton, an X-ray astronomical observatory. We use OMNI solar wind conditions, heavy ion composition data from ACE, the Hodges neutral hydrogen model...of SWEEP was to compare theoretical models of X-ray emission in the terrestrial magnetosphere caused by the Solar Wind Charge Exchange

A selective sweep on a deleterious mutation in CPT1A in Arctic populations

KAUST Repository

Clemente, Florian J.

2014-11-01

Arctic populations live in an environment characterized by extreme cold and the absence of plant foods for much of the year and are likely to have undergone genetic adaptations to these environmental conditions in the time they have been living there. Genome-wide selection scans based on genotype data from native Siberians have previously highlighted a 3 Mb chromosome 11 region containing 79 protein-coding genes as the strongest candidates for positive selection in Northeast Siberians. However, it was not possible to determine which of the genes might be driving the selection signal. Here, using whole-genome high-coverage sequence data, we identified the most likely causative variant as a nonsynonymous G>A transition (rs80356779; c.1436C>T [p.Pro479Leu] on the reverse strand) in CPT1A, a key regulator of mitochondrial long-chain fatty-acid oxidation. Remarkably, the derived allele is associated with hypoketotic hypoglycemia and high infant mortality yet occurs at high frequency in Canadian and Greenland Inuits and was also found at 68% frequency in our Northeast Siberian sample. We provide evidence of one of the strongest selective sweeps reported in humans; this sweep has driven this variant to high frequency in circum-Arctic populations within the last 6-23 ka despite associated deleterious consequences, possibly as a result of the selective advantage it originally provided to either a high-fat diet or a cold environment.

A selective sweep on a deleterious mutation in CPT1A in Arctic populations

KAUST Repository

Clemente, Florian J.; Cardona, Alexia; Inchley, Charlotte E.; Peter, Benjamin M.; Jacobs, Guy; Pagani, Luca; Lawson, Daniel John; Antã o, Tiago; Vicente, Má rio; Mitt, Mario; Degiorgio, Michael; Faltyskova, Zuzana; Xue, Yali; Ayub, Qasim; Szpak, Michal; Mä gi, Reedik; Eriksson, Anders; Manica, Andrea; Raghavan, Maanasa; Rasmussen, Morten Arendt Rendt; Rasmussen, Simon B.; Willerslev, Eske; Vidal-Puig, Antonio J.; Tyler-Smith, Chris; Villems, Richard; Nielsen, Rasmus Wedel; Metspalu, Mait; Malyarchuk, Boris A.; Derenko, Miroslava V.; Kivisild, Toomas

2014-01-01

Arctic populations live in an environment characterized by extreme cold and the absence of plant foods for much of the year and are likely to have undergone genetic adaptations to these environmental conditions in the time they have been living there. Genome-wide selection scans based on genotype data from native Siberians have previously highlighted a 3 Mb chromosome 11 region containing 79 protein-coding genes as the strongest candidates for positive selection in Northeast Siberians. However, it was not possible to determine which of the genes might be driving the selection signal. Here, using whole-genome high-coverage sequence data, we identified the most likely causative variant as a nonsynonymous G>A transition (rs80356779; c.1436C>T [p.Pro479Leu] on the reverse strand) in CPT1A, a key regulator of mitochondrial long-chain fatty-acid oxidation. Remarkably, the derived allele is associated with hypoketotic hypoglycemia and high infant mortality yet occurs at high frequency in Canadian and Greenland Inuits and was also found at 68% frequency in our Northeast Siberian sample. We provide evidence of one of the strongest selective sweeps reported in humans; this sweep has driven this variant to high frequency in circum-Arctic populations within the last 6-23 ka despite associated deleterious consequences, possibly as a result of the selective advantage it originally provided to either a high-fat diet or a cold environment.

Enhancement of the conductivity detection signal in capillary electrophoresis systems using neutral cyclodextrins as sweeping agents.

Science.gov (United States)

Boublík, Milan; Riesová, Martina; Dubský, Pavel; Gaš, Bohuslav

2018-06-01

Conductivity detection is a universal detection technique often encountered in electrophoretic separation systems, especially in modern chip-electrophoresis based devices. On the other hand, it is sparsely combined with another contemporary trend of enhancing limits of detection by means of various preconcentration strategies. This can be attributed to the fact that a preconcentration experimental setup usually brings about disturbances in a conductivity baseline. Sweeping with a neutral sweeping agent seems a good candidate for overcoming this problem. A neutral sweeping agent does not hinder the conductivity detection while a charged analyte may preconcentrate on its boundary due to a decrease in its effective mobility. This study investigates such sweeping systems theoretically, by means of computer simulations, and experimentally. A formula is provided for the reliable estimation of the preconcentration factor. Additionally, it is demonstrated that the conductivity signal can significantly benefit from slowing down the analyte and thus the overall signal enhancement can easily overweight amplification caused solely by the sweeping process. The overall enhancement factor can be deduced a priori from the linearized theory of electrophoresis implemented in the PeakMaster freeware. Sweeping by neutral cyclodextrin is demonstrated on an amplification of a conductivity signal of flurbiprofen in a real drug sample. Finally, a possible formation of unexpected system peaks in systems with a neutral sweeping agent is revealed by the computer simulation and confirmed experimentally. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

S/HIC: Robust Identification of Soft and Hard Sweeps Using Machine Learning.

Directory of Open Access Journals (Sweden)

Daniel R Schrider

2016-03-01

Full Text Available Detecting the targets of adaptive natural selection from whole genome sequencing data is a central problem for population genetics. However, to date most methods have shown sub-optimal performance under realistic demographic scenarios. Moreover, over the past decade there has been a renewed interest in determining the importance of selection from standing variation in adaptation of natural populations, yet very few methods for inferring this model of adaptation at the genome scale have been introduced. Here we introduce a new method, S/HIC, which uses supervised machine learning to precisely infer the location of both hard and soft selective sweeps. We show that S/HIC has unrivaled accuracy for detecting sweeps under demographic histories that are relevant to human populations, and distinguishing sweeps from linked as well as neutrally evolving regions. Moreover, we show that S/HIC is uniquely robust among its competitors to model misspecification. Thus, even if the true demographic model of a population differs catastrophically from that specified by the user, S/HIC still retains impressive discriminatory power. Finally, we apply S/HIC to the case of resequencing data from human chromosome 18 in a European population sample, and demonstrate that we can reliably recover selective sweeps that have been identified earlier using less specific and sensitive methods.

Plasma turbulence measured by fast sweep reflectometry on Tore Supra

International Nuclear Information System (INIS)

Clairet, F.; Vermare, L.; Leclert, G.

2004-01-01

Traditionally devoted to electron density profile measurement we show that fast frequency sweeping reflectometry technique can bring valuable and innovative measurements onto plasma turbulence. While fast frequency sweeping technique is traditionally devoted to electron density radial profile measurements we show in this paper how we can handle the fluctuations of the reflected signal to recover plasma density fluctuation measurements with a high spatial and temporal resolution. Large size turbulence related to magneto-hydrodynamic (MHD) activity and the associated magnetic islands can be detected. The radial profile of the micro-turbulence, which is responsible for plasma anomalous transport processes, is experimentally determined through the fluctuation of the reflected phase signal. (authors)

Plasma turbulence measured by fast sweep reflectometry on Tore Supra

International Nuclear Information System (INIS)

Clairet, F.; Vermare, L.; Heuraux, S.; Leclert, G.

2004-01-01

Traditionally devoted to electron density profile measurement we show that fast frequency sweeping reflectometry technique can bring valuable and innovative measurements onto plasma turbulence. While fast frequency sweeping technique is traditionally devoted to electron density radial profile measurements we show in this paper how we can handle the fluctuations of the reflected signal to recover plasma density fluctuation measurements with a high spatial and temporal resolution. Large size turbulence related to magneto-hydrodynamic (MHD) activity and the associated magnetic islands can be detected. The radial profile of the micro-turbulence, which is responsible for plasma anomalous transport processes, is experimentally determined through the fluctuation of the reflected phase signal

3D flow visualizations by means of laser beam sweeps

International Nuclear Information System (INIS)

Prenel, J.P.; Porcar, R.; Diemunsch, G.

1987-01-01

A method in which two-dimensional aperiodic or periodic sweeps are used to produce three-dimensional light sweeps makes possible the quasi-simultaneous recording of different specific planes of a flow, or the characterization of a fluid without revolution symmetry. The optical device consists of two scanners (whose axes are orthogonal) set into a telescope, allowing fine focusing of the light sheets in the study zone. The method also allows visualizations on skewed surfaces, particularly those of flows without a cylindrical geometry; it is applicable from low velocity, as in heat convection, to supersonic velocity, as in the analysis of a nonaxisymmetric ejector. 8 references

Ka-Band Digital Beamforming and SweepSAR Demonstration for Ice and Solid Earth Topography

Science.gov (United States)

Sadowy, Gregory; Ghaemi, Hirad; Heavy, Brandon; Perkovic, Dragana; Quddus, Momin; Zawadzki, Mark; Moller, Delwyn

2010-01-01

GLISTIN is an instrument concept for a single-pass interferometric SAR operating at 35.6 GHz. To achieve large swath widths using practical levels of transmitter power, a digitally-beamformed planar waveguide array is used. This paper describes results from a ground-based demonstration of a 16-receiver prototype. Furthermore, SweepSAR is emerging as promising technique for achieving very wide swaths for surface change detection. NASA and DLR are studying this approach for the DESDynI and Tandem-L missions. SweepSAR employs a reflector with a digitally-beamformed array feed. We will describe development of an airborne demonstration of SweepSAR using the GLISTIN receiver array and a reflector.

Toward Cooling Uniformity: Investigation of Spiral, Sweeping Holes, and Unconventional Cooling Paradigms

Science.gov (United States)

Shyam, Vikram; Thurman, Douglas R.; Poinsatte, Philip E.; Ameri, Ali A.; Culley, Dennis E.

2018-01-01

Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. Ways to quantify the efficacy of novel cooling holes that are asymmetric, not uniformly spaced or that show variation from hole to hole are presented. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and square holes. A patent-pending spiral hole design showed the highest potential of the nondiffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing ratios of 1.0, 1.5, 2.0, and 2.5 at a density ratio of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS. A section on ideas for future work is included that addresses issues of quantifying cooling uniformity and provides some ideas for changing the way we think about cooling such as changing the direction of cooling or coupling acoustic devices to cooling holes to regulate frequency.

Maximum power point tracking for PV systems under partial shading conditions using current sweeping

International Nuclear Information System (INIS)

Tsang, K.M.; Chan, W.L.

2015-01-01

Highlights: • A novel approach for tracking the maximum power point of photovoltaic systems. • Able to handle both the uniform insolation and partial shading conditions. • Maximum power point tracking based on current sweeping. - Abstract: Partial shading on photovoltaic (PV) arrays causes multiple peaks on the output power–voltage characteristic curve and local searching technique such as perturb and observe (P&O) method could easily fail in searching for the global maximum. Moreover, existing global searching techniques are still not very satisfactory in terms of speed and implementation complexity. In this paper, a fast global maximum power point (MPPT) tracking method which is using current sweeping for photovoltaic arrays under partial shading conditions is proposed. Unlike conventional approach, the proposed method is current based rather than voltage based. The initial maximum power point will be derived based on a current sweeping test and the maximum power point can be enhanced by a finer local search. The speed of the global search is mainly governed by the apparent time constant of the PV array and the generation of a fast current sweeping test. The fast current sweeping test can easily be realized by a DC/DC boost converter with a very fast current control loop. Experimental results are included to demonstrate the effectiveness of the proposed global searching scheme

Using temperature sweeps to investigate rheology of bioplastics

Science.gov (United States)

As part of research toward production of protein-based bioplastics, small amplitude oscillatory shear analyses were performed in the temperature sweep mode to examine protein blends in the presence of wheat flour and glycerol. The elastic modulus (G') of these samples was much higher than the visco...

EFFECT OF SWEEP ANGLE ON THE VORTICAL FLOW OVER DELTA WINGS AT AN ANGLE OF ATTACK OF 10°

Directory of Open Access Journals (Sweden)

JAMES BRETT

2014-12-01

Full Text Available CFD simulations have been used to analyse the vortical flows over sharp edged delta wings with differing sweep angles under subsonic conditions at an angle of attack of 10°. RANS simulations were validated against experimental data for a 65° sweep wing, with a flat cross-section, and the steadiness of the flow field was assessed by comparing the results against unsteady URANS and DES simulations. To assess the effect of sweep angle on the flow field, a range of sweep angles from 65° to 43° were simulated. For moderate sweep wings the primary vortex was observed to detach from the leading edge, undergoing vortex breakdown, and a weaker, replacement, "shadow" vortex was formed. The shadow vortex was observed for sweep angles of 50° and less, and resulted in reduced lift production near the wing tips loss of the stronger primary vortex.

Sweeping Gas Membrane Desalination Using Commercial Hydrophobic Hollow Fiber Membranes; TOPICAL

International Nuclear Information System (INIS)

EVANS, LINDSEY; MILLER, JAMES E.

2002-01-01

Water shortages affect 88 developing countries that are home to half of the world's population. In these places, 80-90% of all diseases and 30% of all deaths result from poor water quality. Furthermore, over the next 25 years, the number of people affected by severe water shortages is expected to increase fourfold. Low cost methods of purifying freshwater, and desalting seawater are required to contend with this destabilizing trend. Membrane distillation (MD) is an emerging technology for separations that are traditionally accomplished via conventional distillation or reverse osmosis. As applied to desalination, MD involves the transport of water vapor from a saline solution through the pores of a hydrophobic membrane. In sweeping gas MD, a flowing gas stream is used to flush the water vapor from the permeate side of the membrane, thereby maintaining the vapor pressure gradient necessary for mass transfer. Since liquid does not penetrate the hydrophobic membrane, dissolved ions are completely rejected by the membrane. MD has a number of potential advantages over conventional desalination including low temperature and pressure operation, reduced membrane strength requirements, compact size, and 100% rejection of non-volatiles. The present work evaluated the suitability of commercially available technology for sweeping gas membrane desalination. Evaluations were conducted with Celgard Liqui-Cel(reg s ign) Extra-Flow 2.5X8 membrane contactors with X-30 and X-40 hydrophobic hollow fiber membranes. Our results show that sweeping gas membrane desalination systems are capable of producing low total dissolved solids (TDS) water, typically 10 ppm or less, from seawater, using low grade heat. However, there are several barriers that currently prevent sweeping gas MD from being a viable desalination technology. The primary problem is that large air flows are required to achieve significant water yields, and the costs associated with transporting this air are prohibitive. To

A field-sweep/field-lock system for superconducting magnets--Application to high-field EPR.

Science.gov (United States)

Maly, Thorsten; Bryant, Jeff; Ruben, David; Griffin, Robert G

2006-12-01

We describe a field-lock/field-sweep system for the use in superconducting magnets. The system is based on a commercially available field mapping unit and a custom designed broad-band 1H NMR probe. The NMR signal of a small water sample is used in a feedback loop to set and control the magnetic field to high accuracy. The current instrumental configuration allows field sweeps of +/-0.4 T and a resolution of up to 10(-5) T (0.1 G) and the performance of the system is demonstrated in a high-field electron paramagnetic resonance (EPR) application. The system should also be of utility in other experiments requiring precise and reproducible sweeps of the magnetic field such as DNP, ENDOR or PELDOR.

A Field-Sweep/Field-Lock System for Superconducting Magnets-Application to High-Field EPR

Science.gov (United States)

Maly, Thorsten; Bryant, Jeff; Ruben, David; Griffin, Robert G.

2007-01-01

We describe a field-lock/field-sweep system for the use in superconducting magnets. The system is based on a commercially available field mapping unit and a custom designed broad-band 1H-NMR probe. The NMR signal of a small water sample is used in a feedback loop to set and control the magnetic field to high accuracy. The current instrumental configuration allows field sweeps of ± 0.4 T and a resolution of up to 10-5 T (0.1 G) and the performance of the system is demonstrated in a high-field electron paramagnetic resonance (EPR) application. The system should also be of utility in other experiments requiring precise and reproducible sweeps of the magnetic field such as DNP, ENDOR or PELDOR. PMID:17027306

EVIDENCE FOR DYNAMICAL CHANGES IN A TRANSITIONAL PROTOPLANETARY DISK WITH MID-INFRARED VARIABILITY

International Nuclear Information System (INIS)

Muzerolle, James; Flaherty, Kevin; Balog, Zoltan; Smith, Paul S.; Rieke, George H.; Furlan, Elise; Allen, Lori; Muench, August; Calvet, Nuria; D'Alessio, Paola; Megeath, S. Thomas; Sherry, William H.

2009-01-01

We present multi-epoch Spitzer Space Telescope observations of the transitional disk LRLL 31 in the 2-3 Myr old star-forming region IC 348. Our measurements show remarkable mid-infrared variability on timescales as short as one week. The infrared continuum emission exhibits systematic wavelength-dependent changes that suggest corresponding dynamical changes in the inner disk structure and variable shadowing of outer disk material. We propose several possible sources for the structural changes, including a variable accretion rate or a stellar or planetary companion embedded in the disk. Our results indicate that variability studies in the infrared can provide important new constraints on protoplanetary disk behavior.

Which System Variables Carry Robust Early Signs of Upcoming Phase Transition? An Ecological Example.

Science.gov (United States)

Negahbani, Ehsan; Steyn-Ross, D Alistair; Steyn-Ross, Moira L; Aguirre, Luis A

2016-01-01

Growth of critical fluctuations prior to catastrophic state transition is generally regarded as a universal phenomenon, providing a valuable early warning signal in dynamical systems. Using an ecological fisheries model of three populations (juvenile prey J, adult prey A and predator P), a recent study has reported silent early warning signals obtained from P and A populations prior to saddle-node (SN) bifurcation, and thus concluded that early warning signals are not universal. By performing a full eigenvalue analysis of the same system we demonstrate that while J and P populations undergo SN bifurcation, A does not jump to a new state, so it is not expected to carry early warning signs. In contrast with the previous study, we capture a significant increase in the noise-induced fluctuations in the P population, but only on close approach to the bifurcation point; it is not clear why the P variance initially shows a decaying trend. Here we resolve this puzzle using observability measures from control theory. By computing the observability coefficient for the system from the recordings of each population considered one at a time, we are able to quantify their ability to describe changing internal dynamics. We demonstrate that precursor fluctuations are best observed using only the J variable, and also P variable if close to transition. Using observability analysis we are able to describe why a poorly observable variable (P) has poor forecasting capabilities although a full eigenvalue analysis shows that this variable undergoes a bifurcation. We conclude that observability analysis provides complementary information to identify the variables carrying early-warning signs about impending state transition.

Simulation and theory of spontaneous TAE frequency sweeping

International Nuclear Information System (INIS)

Wang Ge; Berk, H.L.

2012-01-01

A simulation model, based on the linear tip model of Rosenbluth, Berk and Van Dam (RBV), is developed to study frequency sweeping of toroidal Alfvén eigenmodes (TAEs). The time response of the background wave in the RBV model is given by a Volterra integral equation. This model captures the properties of TAE waves both in the gap and in the continuum. The simulation shows that phase space structures form spontaneously at frequencies close to the linearly predicted frequency, due to resonant particle–wave interactions and background dissipation. The frequency sweeping signals are found to chirp towards the upper and lower continua. However, the chirping signals penetrate only the lower continuum, whereupon the frequency chirps and mode amplitude increases in synchronism to produce an explosive solution. An adiabatic theory describing the evolution of a chirping signal is developed which replicates the chirping dynamics of the simulation in the lower continuum. This theory predicts that a decaying chirping signal will terminate at the upper continuum though in the numerical simulation the hole disintegrates before the upper continuum is reached. (paper)

Simulation and theory of spontaneous TAE frequency sweeping

Science.gov (United States)

Wang, Ge; Berk, H. L.

2012-09-01

A simulation model, based on the linear tip model of Rosenbluth, Berk and Van Dam (RBV), is developed to study frequency sweeping of toroidal Alfvén eigenmodes (TAEs). The time response of the background wave in the RBV model is given by a Volterra integral equation. This model captures the properties of TAE waves both in the gap and in the continuum. The simulation shows that phase space structures form spontaneously at frequencies close to the linearly predicted frequency, due to resonant particle-wave interactions and background dissipation. The frequency sweeping signals are found to chirp towards the upper and lower continua. However, the chirping signals penetrate only the lower continuum, whereupon the frequency chirps and mode amplitude increases in synchronism to produce an explosive solution. An adiabatic theory describing the evolution of a chirping signal is developed which replicates the chirping dynamics of the simulation in the lower continuum. This theory predicts that a decaying chirping signal will terminate at the upper continuum though in the numerical simulation the hole disintegrates before the upper continuum is reached.

A new interpretation of distortion artifacts in sweep measurements

DEFF Research Database (Denmark)

Torras Rosell, Antoni; Jacobsen, Finn

2011-01-01

The characterization of acoustical spaces by means of impulse response measurements is often biased by the nonlinear behavior of the loudspeaker used to excite the system under test. In this context the distortion immunity provided by the sweep technique has been investigated. The results show...

A Parallel Sweeping Preconditioner for Heterogeneous 3D Helmholtz Equations

KAUST Repository

Poulson, Jack

2013-05-02

A parallelization of a sweeping preconditioner for three-dimensional Helmholtz equations without large cavities is introduced and benchmarked for several challenging velocity models. The setup and application costs of the sequential preconditioner are shown to be O(γ2N4/3) and O(γN logN), where γ(ω) denotes the modestly frequency-dependent number of grid points per perfectly matched layer. Several computational and memory improvements are introduced relative to using black-box sparse-direct solvers for the auxiliary problems, and competitive runtimes and iteration counts are reported for high-frequency problems distributed over thousands of cores. Two open-source packages are released along with this paper: Parallel Sweeping Preconditioner (PSP) and the underlying distributed multifrontal solver, Clique. © 2013 Society for Industrial and Applied Mathematics.

The Effects of Sweeping Jet Actuator Parameters on Flow Separation Control

Science.gov (United States)

Koklu, Mehti

2015-01-01

A parametric experimental study was performed with sweeping jet actuators (fluidic oscillators) to determine their effectiveness in controlling flow separation on an adverse pressure gradient ramp. Actuator parameters that were investigated include blowing coefficients, operation mode, pitch and spreading angles, streamwise location, aspect ratio, and scale. Surface pressure measurements and surface oil flow visualization were used to characterize the effects of these parameters on the actuator performance. 2D Particle Image Velocimetry measurements of the flow field over the ramp and hot-wire measurements of the actuator's jet flow were also obtained for selective cases. In addition, the sweeping jet actuators were compared to other well-known flow control techniques such as micro-vortex generators, steady blowing, and steady vortex-generating jets. The results confirm that the sweeping jet actuators are more effective than steady blowing and steady vortex-generating jets. The results also suggest that an actuator with a larger spreading angle placed closer to the location where the flow separates provides better performance. For the cases tested, an actuator with an aspect ratio, which is the width/depth of the actuator throat, of 2 was found to be optimal. For a fixed momentum coefficient, decreasing the aspect ratio to 1 produced weaker vortices while increasing the aspect ratio to 4 reduced coverage area. Although scaling down the actuator (based on the throat dimensions) from 0.25 inch x 0.125 inch to 0.15 inch x 0.075 inch resulted in similar flow control performance, scaling down the actuator further to 0.075 inch x 0.0375 inch reduced the actuator efficiency by reducing the coverage area and the amount of mixing in the near-wall region. The results of this study provide insight that can be used to design and select the optimal sweeping jet actuator configuration for flow control applications.

Fast sweeping methods for hyperbolic systems of conservation laws at steady state II

Science.gov (United States)

Engquist, Björn; Froese, Brittany D.; Tsai, Yen-Hsi Richard

2015-04-01

The idea of using fast sweeping methods for solving stationary systems of conservation laws has previously been proposed for efficiently computing solutions with sharp shocks. We further develop these methods to allow for a more challenging class of problems including problems with sonic points, shocks originating in the interior of the domain, rarefaction waves, and two-dimensional systems. We show that fast sweeping methods can produce higher-order accuracy. Computational results validate the claims of accuracy, sharp shock curves, and optimal computational efficiency.

A discrete element model for soil-sweep interaction in three different soils

DEFF Research Database (Denmark)

Chen, Y; Munkholm, Lars Juhl; Nyord, Tavs

2013-01-01

. To serve the model development, the sweep was tested in three different soils (coarse sand, loamy sand, and sandy loam). In the tests, soil cutting forces (draught and vertical forces) and soil disturbance characteristics (soil cross-section disturbance and surface deformation) resulting from the sweep...... were measured. The measured draught and vertical forces were used in calibrations of the most sensitive model parameter, particle stiffness. The calibrated particle stiffness was 0.75 × 103 N m−1 for the coarse sand, 2.75 × 103 N m−1 for the loamy sand, and 6 × 103 N m−1 for the sandy loam...

Procedures for waste management from street sweeping and stormwater systems.

Science.gov (United States)

2016-05-01

Street sweeping and storm water system cleaning activities are conducted regularly by ODOT to comply with NPDES permit requirements and to ensure roadway safety. Once collected, these materials are classified as solid waste and require cost-effective...

Variation sweep rate cyclic voltammetry on the capacitance electrode activated carbon/PVDF with polymer electrolyte

Science.gov (United States)

Rohmawati, L.; Setyarsih, W.; Nurjannah, T.

2018-03-01

Sweep rate of the process voltammetry cyclic characterization is very influential towards the electrode capacitance value, especially on activated carbon electrodes/PVDF. A simple method of this research by use a mixing for electrode activated carbon/10 wt. % PVDF and the separator is made of a polymer electrolyte (PVA/H3PO4) by a sol gel method. The prototype supercapacitor is made in the form of a sandwich with a separator placed between two electrodes. Electrodes and separators are arranged in layers at a pressure of 1500 psi, then heated at 50°C for 10 minutes. Next done cyclic voltammetry in a potential range of -1 V to 1 V with a sweep rate of 5 mV/s, 10 mV/s, 20 mV/s, 25 mV/s and 50 mV/s. This results of curves voltammogram is reversible, the most wide curve on the sweep rate of 5 mV/s and most narrow curve on a sweep rate of 50 mV/s. Supercapacitor capacitance values obtained by 86 F/g, 43 F/g, 21 F/g, 16 F/g, and 8 F/g.

Influence of additives and impurities in sweep gas and solid tritium release behaviour from lithium ceramics (review)

International Nuclear Information System (INIS)

Tanaka, Satoru

1991-01-01

Tritium release from solid breeding material is affected by small amounts of additives or impurities in the sweep gas or solid itself. Addition of hydrogen or water vapor to the sweep gas is reported to enhance the surface reaction of tritium release. Doping to solid breeder with elements of different valence from lithium has a possibility to improve tritium diffusion in the solid. Surface reaction and migration behavior in bulk are believed to be also affected by impurities in the sweep gas and in the solid. In order to model tritium release behavior in the blanket of fusion reactor, the mechanism of interaction with these additives or impurities must be quantitatively formulated. However, the mechanism of these remains to be elucidated. In this paper effects of these additives and impurities on tritium migration are reviewed. The mechanism of surface reaction for He+H 2 sweep gas is also discussed. (orig.)

Exact solutions for oscillatory shear sweep behaviors of complex fluids from the Oldroyd 8-constant framework

Science.gov (United States)

Saengow, Chaimongkol; Giacomin, A. Jeffrey

2018-03-01

In this paper, we provide a new exact framework for analyzing the most commonly measured behaviors in large-amplitude oscillatory shear flow (LAOS), a popular flow for studying the nonlinear physics of complex fluids. Specifically, the strain rate sweep (also called the strain sweep) is used routinely to identify the onset of nonlinearity. By the strain rate sweep, we mean a sequence of LAOS experiments conducted at the same frequency, performed one after another, with increasing shear rate amplitude. In this paper, we give exact expressions for the nonlinear complex viscosity and the corresponding nonlinear complex normal stress coefficients, for the Oldroyd 8-constant framework for oscillatory shear sweeps. We choose the Oldroyd 8-constant framework for its rich diversity of popular special cases (we list 18 of these). We evaluate the Fourier integrals of our previous exact solution to get exact expressions for the real and imaginary parts of the complex viscosity, and for the complex normal stress coefficients, as functions of both test frequency and shear rate amplitude. We explore the role of infinite shear rate viscosity on strain rate sweep responses for the special case of the corotational Jeffreys fluid. We find that raising η∞ raises the real part of the complex viscosity and lowers the imaginary. In our worked examples, we thus first use the corotational Jeffreys fluid, and then, for greater accuracy, we use the Johnson-Segalman fluid, to describe the strain rate sweep response of molten atactic polystyrene. For our comparisons with data, we use the Spriggs relations to generalize the Oldroyd 8-constant framework to multimode. Our generalization yields unequivocally, a longest fluid relaxation time, used to assign Weissenberg and Deborah numbers to each oscillatory shear flow experiment. We then locate each experiment in the Pipkin space.

Decoherence in a dynamical quantum phase transition of the transverse Ising chain

International Nuclear Information System (INIS)

Mostame, Sarah; Schaller, Gernot; Schuetzhold, Ralf

2007-01-01

For the prototypical example of the Ising chain in a transverse field, we study the impact of decoherence on the sweep through a second-order quantum phase transition. Apart from the advance in the general understanding of the dynamics of quantum phase transitions, these findings are relevant for adiabatic quantum algorithms due to the similarities between them. It turns out that (in contrast to first-order transitions studied previously) the impact of decoherence caused by a weak coupling to a rather general environment increases with system size (i.e., number of spins or qubits), which might limit the scalability of the system

Evidence for Abnormal H α Variability During Near-transit Observations of HD 189733 b

International Nuclear Information System (INIS)

Cauley, P. Wilson; Redfield, Seth; Jensen, Adam G.

2017-01-01

Changes in levels of stellar activity can mimic absorption signatures in transmission spectra from circumplanetary material. Thus, it is critical to understand the frequency and magnitude of these changes in order to attribute any particular signal to the circumplanetary environment. We present short-cadence, high-resolution out-of-transit H α spectra for the hot Jupiter host HD 189733 in order to establish the frequency and magnitude of intrinsic stellar variations in the H α line core. We find that changes in the line core strength similar to those observed immediately pre- and post-transit in two independent data sets are uncommon. This suggests that the observed near-transit signatures are either due to absorption of circumplanetary material or they occur preferentially in time, very near planetary transits. In either case, the evidence for abnormal H α variability is strengthened, though the short-cadence out-of-transit data do not argue for circumplanetary absorption versus stellar activity caused by a star–planet interaction. Further out-of-transit monitoring at higher signal-to-noise would be useful to more strictly constrain the frequency of the near-transit changes in the H α line core.

Evidence for Abnormal H α Variability During Near-transit Observations of HD 189733 b

Energy Technology Data Exchange (ETDEWEB)

Cauley, P. Wilson; Redfield, Seth [Wesleyan University Astronomy Department, Van Vleck Observatory, 96 Foss Hill Drive, Middletown, CT 06459 (United States); Jensen, Adam G., E-mail: pcauley@wesleyan.edu [University of Nebraska-Kearney Department of Physics and Astronomy, 24011 11th Avenue, Kearney, NE 68849 (United States)

2017-04-01

Changes in levels of stellar activity can mimic absorption signatures in transmission spectra from circumplanetary material. Thus, it is critical to understand the frequency and magnitude of these changes in order to attribute any particular signal to the circumplanetary environment. We present short-cadence, high-resolution out-of-transit H α spectra for the hot Jupiter host HD 189733 in order to establish the frequency and magnitude of intrinsic stellar variations in the H α line core. We find that changes in the line core strength similar to those observed immediately pre- and post-transit in two independent data sets are uncommon. This suggests that the observed near-transit signatures are either due to absorption of circumplanetary material or they occur preferentially in time, very near planetary transits. In either case, the evidence for abnormal H α variability is strengthened, though the short-cadence out-of-transit data do not argue for circumplanetary absorption versus stellar activity caused by a star–planet interaction. Further out-of-transit monitoring at higher signal-to-noise would be useful to more strictly constrain the frequency of the near-transit changes in the H α line core.

TIME CALIBRATED OSCILLOSCOPE SWEEP CIRCUIT

Science.gov (United States)

Smith, V.L.; Carstensen, H.K.

1959-11-24

An improved time calibrated sweep circuit is presented, which extends the range of usefulness of conventional oscilloscopes as utilized for time calibrated display applications in accordance with U. S. Patent No. 2,832,002. Principal novelty resides in the provision of a pair of separate signal paths, each of which is phase and amplitude adjustable, to connect a high-frequency calibration oscillator to the output of a sawtooth generator also connected to the respective horizontal deflection plates of an oscilloscope cathode ray tube. The amplitude and phase of the calibration oscillator signals in the two signal paths are adjusted to balance out feedthrough currents capacitively coupled at high frequencies of the calibration oscillator from each horizontal deflection plate to the vertical plates of the cathode ray tube.

Flow field characteristics of impinging sweeping jets: TR-PIV measurement

Science.gov (United States)

Wen, Xin; Peng, Di; Liu, Yingzheng; Tang, Hui

2017-11-01

Influence of Reynolds number of sweeping jets on its impinging flow fields was extensively investigated in a water tank. Toward this end, a fluidic oscillator was specially designed to produce spatially sweeping jets which imping on a flat plate. Six Reynolds numbers were tested by controlling the supply flow rate of the fluidic oscillator. Impinging flow fields were captured by time-resolved Particle Image Velocimetry (TR-PIV) measurement. Reference signals were extracted from the flow fields for phase reconstruction. The oscillating flow fields with super-harmonic frequency at different regions were discussed in term of the phase-averaged velocity, vorticity and turbulent velocity. Dynamic mode decomposition (DMD) was used to capture the most-energetic flow patterns with distinct frequencies. By projecting the phase-averaged flow fields onto a reduced basis of DMD modes, the phase correlation between the distinct flow patterns were analyzed under different Reynolds numbers.

Residual sweeping errors in turbulent particle pair diffusion in a Lagrangian diffusion model.

Science.gov (United States)

Malik, Nadeem A

2017-01-01

Thomson, D. J. & Devenish, B. J. [J. Fluid Mech. 526, 277 (2005)] and others have suggested that sweeping effects make Lagrangian properties in Kinematic Simulations (KS), Fung et al [Fung J. C. H., Hunt J. C. R., Malik N. A. & Perkins R. J. J. Fluid Mech. 236, 281 (1992)], unreliable. However, such a conclusion can only be drawn under the assumption of locality. The major aim here is to quantify the sweeping errors in KS without assuming locality. Through a novel analysis based upon analysing pairs of particle trajectories in a frame of reference moving with the large energy containing scales of motion it is shown that the normalized integrated error [Formula: see text] in the turbulent pair diffusivity (K) due to the sweeping effect decreases with increasing pair separation (σl), such that [Formula: see text] as σl/η → ∞; and [Formula: see text] as σl/η → 0. η is the Kolmogorov turbulence microscale. There is an intermediate range of separations 1 < σl/η < ∞ in which the error [Formula: see text] remains negligible. Simulations using KS shows that in the swept frame of reference, this intermediate range is large covering almost the entire inertial subrange simulated, 1 < σl/η < 105, implying that the deviation from locality observed in KS cannot be atributed to sweeping errors. This is important for pair diffusion theory and modeling. PACS numbers: 47.27.E?, 47.27.Gs, 47.27.jv, 47.27.Ak, 47.27.tb, 47.27.eb, 47.11.-j.

Outcome of Membrane Sweeping in Reducing Induction Rates in Post-Date Pregnancies

International Nuclear Information System (INIS)

Saleem, U.; Mustafa, N.; Akhtar, S.

2013-01-01

Objectives: To determine the effectiveness of membrane sweeping in reducing need for induction of labour in post-date pregnancies and to enlist types and frequencies of complications experienced with membrane sweeping. Study Design: Randomized Control trial. Setting and Duration of Study: The study was carried out at Department of Obstetrics and Gynaecology, Combined Military Hospital, Lahore from February 2007 to April 2008. Patients and Methods: One hundred primi or second gravidas with uncomplicated singleton pregnancies having cephalic presentation at 40+1-5 weeks of gestation were enrolled after informed consent, and divided randomly into two groups of fifty each. Biophysical profile of 8/8 for each case was ensured. Group A underwent membrane sweeping while group B did not. All patients not having spontaneous labour were induced at 40+5 weeks. Data regarding number of patients having spontaneous labour or induction of labour was recorded. Mode of delivery either vaginal or cesarean birth was also recorded. In group A occurence of complications i.e vaginal bleeding or leaking, discomfort, irregular pains, fever and neonatal sepsis was recorded. Results: The difference in rate of spontaneous labor, induction rate and mode of delivery was insignificant between both the groups (p>0.05). In group A, 44% felt discomfort, 4% had bleeding per vaginum, 2% had leaking per vaginum and 28% had more than one complication. There were no cases of maternal or neonatal sepsis. Twenty percent did not have any side effects. Conclusion: Sweeping of membranes is not effective in reducing induction rates in post dates pregnancies. It does not improve the spontaneous labour rate and there is no effect on the mode of delivery. Therefore, any potential benefits of this intervention must be balanced against risk of maternal discomfort and other adverse effects. (author)

Sweeping Jet Actuators - A New Design Tool for High Lift Generation

Science.gov (United States)

Graff, Emilio; Seele, Roman; Lin, John C.; Wygnanski, Israel

2013-01-01

Active Flow Control (AFC) experiments performed at the Caltech Lucas Wind Tunnel on a generic airplane vertical tail model proved the effectiveness of sweeping jets in improving the control authority of a rudder. The results indicated that a momentum coefficient (C(sub u)) of approximately 2% increased the side force in excess of 50% at the maximum conventional rudder deflection angle in the absence of yaw. However, sparsely distributed actuators providing a collective C(sub u) approx. = 0.1% were able to increase the side force in excess of 20%. This result is achieved by reducing the spanwise flow along the swept back rudder and its success is attributed to the large sweep back angle of the vertical tail. This current effort was sponsored by the NASA Environmentally Responsible Aviation (ERA) project.

Effect of Sweep on Cavity Flow Fields at Subsonic and Transonic Speeds

Science.gov (United States)

Tracy, Maureen B.; Plentovich, Elizabeth B.; Hemsch, Michael J.; Wilcox, Floyd J.

2012-01-01

An experimental investigation was conducted in the NASA Langley 7 x 10-Foot High Speed Tunnel (HST) to study the effect of leading- and trailing-edge sweep on cavity flow fields for a range of cavity length-to-height (l/h) ratios. The free-stream Mach number was varied from 0.2 to 0.8. The cavity had a depth of 0.5 inches, a width of 2.5 inches, and a maximum length of 12.0 inches. The leading- and trailing-edge sweep was adjusted using block inserts to achieve leading edge sweep angles of 65 deg, 55 deg, 45 deg, 35 deg, and 0 deg. The fore and aft cavity walls were always parallel. The aft wall of the cavity was remotely positioned to achieve a range of length-to-depth ratios. Fluctuating- and static-pressure data were obtained on the floor of the cavity. The fluctuating pressure data were used to determine whether or not resonance occurred in the cavity rather than to provide a characterization of the fluctuating pressure field. Qualitative surface flow visualization was obtained using a technique in which colored water was introduced into the model through static-pressure orifices. A complete tabulation of the mean static-pressure data for the swept leading edge cavities is included.

Lock-free parallel and concurrent garbage collection by mark&sweep

NARCIS (Netherlands)

Gao, H.; Groote, J. F.; Hesselink, W. H.

2007-01-01

This paper presents a lock-free algorithm for mark&sweep garbage collection (GC) in a realistic model using synchronization primitives load-linked/store-conditional (LL/SC) or compare-and-swap (CAS) offered by machine arch i lectures. The algorithm is concurrent in the sense that garbage collection

NEW INSIGHT INTO THE SOLAR SYSTEM’S TRANSITION DISK PHASE PROVIDED BY THE METAL-RICH CARBONACEOUS CHONDRITE ISHEYEVO

International Nuclear Information System (INIS)

Morris, Melissa A.; Garvie, Laurence A. J.; Knauth, L. Paul

2015-01-01

Many aspects of planet formation are controlled by the amount of gas remaining in the natal protoplanetary disks (PPDs). Infrared observations show that PPDs undergo a transition stage at several megayears, during which gas densities are reduced. Our Solar System would have experienced such a stage. However, there is currently no data that provides insight into this crucial time in our PPD’s evolution. We show that the Isheyevo meteorite contains the first definitive evidence for a transition disk stage in our Solar System. Isheyevo belongs to a class of metal-rich meteorites whose components have been dated at almost 5 Myr after formation of Ca, Al-rich inclusions, and exhibits unique sedimentary layers that imply formation through gentle sedimentation. We show that such layering can occur via the gentle sweep-up of material found in the impact plume resulting from the collision of two planetesimals. Such sweep-up requires gas densities consistent with observed transition disks (10 −12 –10 −11 g cm −3 ). As such, Isheyevo presents the first evidence of our own transition disk and provides new constraints on the evolution of our solar nebula

NEW INSIGHT INTO THE SOLAR SYSTEM’S TRANSITION DISK PHASE PROVIDED BY THE METAL-RICH CARBONACEOUS CHONDRITE ISHEYEVO

Energy Technology Data Exchange (ETDEWEB)

Morris, Melissa A. [State University of New York, Cortland, NY 13045 (United States); Garvie, Laurence A. J. [Center for Meteorite Studies, Arizona State University, Tempe, AZ 85287 (United States); Knauth, L. Paul, E-mail: melissa.morris@cortland.edu [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)

2015-03-10

Many aspects of planet formation are controlled by the amount of gas remaining in the natal protoplanetary disks (PPDs). Infrared observations show that PPDs undergo a transition stage at several megayears, during which gas densities are reduced. Our Solar System would have experienced such a stage. However, there is currently no data that provides insight into this crucial time in our PPD’s evolution. We show that the Isheyevo meteorite contains the first definitive evidence for a transition disk stage in our Solar System. Isheyevo belongs to a class of metal-rich meteorites whose components have been dated at almost 5 Myr after formation of Ca, Al-rich inclusions, and exhibits unique sedimentary layers that imply formation through gentle sedimentation. We show that such layering can occur via the gentle sweep-up of material found in the impact plume resulting from the collision of two planetesimals. Such sweep-up requires gas densities consistent with observed transition disks (10{sup −12}–10{sup −11} g cm{sup −3}). As such, Isheyevo presents the first evidence of our own transition disk and provides new constraints on the evolution of our solar nebula.

Suppression of nonlinear frequency-sweeping of resonant interchange modes in a magnetic dipole with applied radio frequency fields

International Nuclear Information System (INIS)

Maslovsky, D.; Levitt, B.; Mauel, M. E.

2003-01-01

Interchange instabilities excited by energetic electrons trapped by a magnetic dipole nonlinearly saturate and exhibit complex, coherent spectral characteristics and frequency sweeping [H. P. Warren and M. E. Mauel, Phys. Plasmas 2, 4185 (1995)]. When monochromatic radio frequency (rf) fields are applied in the range of 100-1000 MHz, the saturation behavior of the interchange instability changes dramatically. For applied fields of sufficient intensity and pulse-length, coherent interchange fluctuations are suppressed and frequency sweeping is eliminated. When rf fields are switched off, coherent frequency sweeping reappears. Since low frequency interchange instabilities preserve the electron's first and second adiabatic invariants, these observations can be interpreted as resulting from nonlinear resonant wave-particle interactions described within a particle phase-space, (ψ,φ), comprised of the third adiabatic invariant and the azimuthal angle. Self-consistent numerical simulation is used to study (1) the nonlinear development of the instability, (2) the radial mode structure of the interchange instability, and (3) the suppression of frequency sweeping. When the applied rf heating is modeled as an 'rf collisionality', the simulation reproduces frequency sweeping suppression and suggests an explanation for the observations that is consistent with Berk and co-workers [H. L. Berk et al., Phys. Plasmas 6, 3102 (1999)

Analysing Infinite-State Systems by Combining Equivalence Reduction and the Sweep-Line Method

DEFF Research Database (Denmark)

Mailund, Thomas

2002-01-01

The sweep-line method is a state space exploration method for on-the-fly verification aimed at systems exhibiting progress. Presence of progress in the system makes it possible to delete certain states during state space generation, which reduces the memory used for storing the states. Unfortunat......The sweep-line method is a state space exploration method for on-the-fly verification aimed at systems exhibiting progress. Presence of progress in the system makes it possible to delete certain states during state space generation, which reduces the memory used for storing the states....... Unfortunately, the same progress that is used to improve memory performance in state space exploration often leads to an infinite state space: The progress in the system is carried over to the states resulting in infinitely many states only distinguished through the progress. A finite state space can...... property essential for the sweep-line method. We evaluate the new method on two case studies, showing significant improvements in performance, and we briefly discuss the new method in the context of Timed Coloured Petri Nets, where the “increasing global time” semantics can be exploited for more efficient...

Modelling for near-surface interaction of lithium ceramics and sweep-gas by use of cellular automation

International Nuclear Information System (INIS)

Shimura, K.; Terai, T.; Yamawaki, M.; Yamaguchi, K.

2003-01-01

Tritium release from the lithium ceramics as a fusion reactor breeder material is strongly affected by the composition of the sweep-gas as result of its influences with the material's surface. The typical surface processes which play important roles are adsorption, desorption and interaction between vacancy site and the constituents of the sweep-gas. Among a large number of studies and models, yet it seems to be difficult to model the overall behaviour of those processes due to its complex time-transient nature. In the present work the coarse grained atomic simulation based on the Cellular Automaton (CA) is used to model the dynamics of near-surface interaction between Li 2 O surface and sweep-gas that is consisting of a noble gas, hydrogen gas and water vapour. (author)

Acidic sweep gas with carbonic anhydrase coated hollow fiber membranes synergistically accelerates CO2 removal from blood.

Science.gov (United States)

Arazawa, D T; Kimmel, J D; Finn, M C; Federspiel, W J

2015-10-01

The use of extracorporeal carbon dioxide removal (ECCO2R) is well established as a therapy for patients suffering from acute respiratory failure. Development of next generation low blood flow (carbonic anhydrase (CA) immobilized bioactive hollow fiber membrane (HFM) which significantly accelerates CO2 removal from blood in model gas exchange devices by converting bicarbonate to CO2 directly at the HFM surface. This present study tested the hypothesis that dilute sulfur dioxide (SO2) in oxygen sweep gas could further increase CO2 removal by creating an acidic microenvironment within the diffusional boundary layer adjacent to the HFM surface, facilitating dehydration of bicarbonate to CO2. CA was covalently immobilized onto poly (methyl pentene) (PMP) HFMs through glutaraldehyde activated chitosan spacers, potted in model gas exchange devices (0.0151 m(2)) and tested for CO2 removal rate with oxygen (O2) sweep gas and a 2.2% SO2 in oxygen sweep gas mixture. Using pure O2 sweep gas, CA-PMP increased CO2 removal by 31% (258 mL/min/m(2)) compared to PMP (197 mL/min/m(2)) (Premoval by 17% (230 mL/min/m(2)) compared to pure oxygen sweep gas control (Premoval increased by 109% (411 mL/min/m(2)) (Premoval, and when used in combination with bioactive CA-HFMs has a synergistic effect to more than double CO2 removal while maintaining physiologic pH. Through these technologies the next generation of intravascular and paracorporeal respiratory assist devices can remove more CO2 with smaller blood contacting surface areas. A clinical need exists for more efficient respiratory assist devices which utilize low blood flow rates (removal efficiency by shifting equilibrium from bicarbonate to gaseous CO2, through either a bioactive carbonic anhydrase enzyme coating or bulk blood acidification with lactic acid. In this study we demonstrate a novel approach to local blood acidification using an acidified sweep gas in combination with a bioactive coating to more than double CO2 removal

Scaling behavior and variable hopping conductivity in the quantum Hall plateau transition

International Nuclear Information System (INIS)

Tu, Tao; Zhao, Yong-Jie; Guo, Guo-Ping; Hao, Xiao-Jie; Guo, Guang-Can

2007-01-01

We have measured the temperature dependence of the longitudinal resistivity ρ xx of a two-dimensional electron system in the regime of the quantum Hall plateau transition. We extracted the quantitative form of scaling function for ρ xx and compared it with the results of ordinary scaling theory and variable range hopping based theory. We find that the two alternative theoretically proposed scaling functions are valid in different regions

Effect of elasticity during viscoelastic polymer flooding : a possible mechanism of increasing the sweep efficiency

Energy Technology Data Exchange (ETDEWEB)

Urbissinova, T.S.; Trivedi, J.J.; Kuru, E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

2010-12-15

This paper discussed a laboratory experiment undertaken to study how the elasticity of polymer-based fluids affects microscopic sweep efficiency, which has implications for enhanced oil recovery processes. In a series of experiments, polymer solutions with the same shear viscosity but notably different elastic characteristics were injected through a mineral-oil-saturated sandpack. The experiments involved a special core holder that was designed to simulate radial flow. The solution was injected via a perforated injection line located in the centre of the cell, and fluids were produced by way of 2 production lines located at the periphery. The shear rate used in the experiments was within the range of field applications. Using polymer solutions with similar shear viscosity behaviour and different elasticity allowed the effect of elasticity on sweep efficiency to be singled out. It was concluded that adjusting the molecular weight distribution of the solution at a constant shear viscosity and polymer concentration could improve the sweep efficiency of a polymeric fluid. The higher-elasticity polymer solution had a higher resistance to flow through porous media, resulting in better sweep efficiency and lower residual oil saturation. The objective of the study was to isolate elasticity from the other parameters that affect displacement efficiency to show the individual effect of elasticity on oil recovery. 20 refs., 5 tabs., 14 figs.

New Theories on Boundary Layer Transition and Turbulence Formation

Directory of Open Access Journals (Sweden)

Chaoqun Liu

2012-01-01

Full Text Available This paper is a short review of our recent DNS work on physics of late boundary layer transition and turbulence. Based on our DNS observation, we propose a new theory on boundary layer transition, which has five steps, that is, receptivity, linear instability, large vortex structure formation, small length scale generation, loss of symmetry and randomization to turbulence. For turbulence generation and sustenance, the classical theory, described with Richardson's energy cascade and Kolmogorov length scale, is not observed by our DNS. We proposed a new theory on turbulence generation that all small length scales are generated by “shear layer instability” through multiple level ejections and sweeps and consequent multiple level positive and negative spikes, but not by “vortex breakdown.” We believe “shear layer instability” is the “mother of turbulence.” The energy transferring from large vortices to small vortices is carried out by multiple level sweeps, but does not follow Kolmogorov's theory that large vortices pass energy to small ones through vortex stretch and breakdown. The loss of symmetry starts from the second level ring cycle in the middle of the flow field and spreads to the bottom of the boundary layer and then the whole flow field.

Lax-Friedrichs sweeping scheme for static Hamilton-Jacobi equations

International Nuclear Information System (INIS)

Kao, C.Y.; Osher, Stanley; Qian Jianliang

2004-01-01

We propose a simple, fast sweeping method based on the Lax-Friedrichs monotone numerical Hamiltonian to approximate viscosity solutions of arbitrary static Hamilton-Jacobi equations in any number of spatial dimensions. By using the Lax-Friedrichs numerical Hamiltonian, we can easily obtain the solution at a specific grid point in terms of its neighbors, so that a Gauss-Seidel type nonlinear iterative method can be utilized. Furthermore, by incorporating a group-wise causality principle into the Gauss-Seidel iteration by following a finite group of characteristics, we have an easy-to-implement, sweeping-type, and fast convergent numerical method. However, unlike other methods based on the Godunov numerical Hamiltonian, some computational boundary conditions are needed in the implementation. We give a simple recipe which enforces a version of discrete min-max principle. Some convergence analysis is done for the one-dimensional eikonal equation. Extensive 2-D and 3-D numerical examples illustrate the efficiency and accuracy of the new approach. To our knowledge, this is the first fast numerical method based on discretizing the Hamilton-Jacobi equation directly without assuming convexity and/or homogeneity of the Hamiltonian

Lax-Friedrichs sweeping scheme for static Hamilton-Jacobi equations

Science.gov (United States)

Kao, Chiu Yen; Osher, Stanley; Qian, Jianliang

2004-05-01

We propose a simple, fast sweeping method based on the Lax-Friedrichs monotone numerical Hamiltonian to approximate viscosity solutions of arbitrary static Hamilton-Jacobi equations in any number of spatial dimensions. By using the Lax-Friedrichs numerical Hamiltonian, we can easily obtain the solution at a specific grid point in terms of its neighbors, so that a Gauss-Seidel type nonlinear iterative method can be utilized. Furthermore, by incorporating a group-wise causality principle into the Gauss-Seidel iteration by following a finite group of characteristics, we have an easy-to-implement, sweeping-type, and fast convergent numerical method. However, unlike other methods based on the Godunov numerical Hamiltonian, some computational boundary conditions are needed in the implementation. We give a simple recipe which enforces a version of discrete min-max principle. Some convergence analysis is done for the one-dimensional eikonal equation. Extensive 2-D and 3-D numerical examples illustrate the efficiency and accuracy of the new approach. To our knowledge, this is the first fast numerical method based on discretizing the Hamilton-Jacobi equation directly without assuming convexity and/or homogeneity of the Hamiltonian.

Sweeping total reflection X-ray fluorescence optimisation to monitor the metallic contamination into IC manufacturing

International Nuclear Information System (INIS)

Borde, Yannick; Danel, Adrien; Roche, Agnes; Veillerot, Marc

2008-01-01

Among the methods available on the market today to control as metallic contamination in integrated circuit manufacturing, Sweeping Total reflection X-ray Fluorescence mode appears a very good method, providing fast and entire wafer mapping. With the goal of a pertinent use of Sweeping Total reflection X-ray Fluorescence in advanced Integrated Circuit manufacturing this work discusses how acceptable levels of contamination specified by the production (low levels to be detected) can be taken into account. The relation between measurement results (surface coverage, throughput, low limit of detection, limit of quantification, quantification of localized contamination) and Sweeping Total reflection X-ray Fluorescence parameters (number of measurement points and integration time per point) is presented in details. In particular, a model is proposed to explain the mismatch between actual surface contamination in a localized spot on wafer and Total reflection X-ray Fluorescence reading. Both calibration and geometric issues have been taken into account

A second order discontinuous Galerkin fast sweeping method for Eikonal equations

Science.gov (United States)

Li, Fengyan; Shu, Chi-Wang; Zhang, Yong-Tao; Zhao, Hongkai

2008-09-01

In this paper, we construct a second order fast sweeping method with a discontinuous Galerkin (DG) local solver for computing viscosity solutions of a class of static Hamilton-Jacobi equations, namely the Eikonal equations. Our piecewise linear DG local solver is built on a DG method developed recently [Y. Cheng, C.-W. Shu, A discontinuous Galerkin finite element method for directly solving the Hamilton-Jacobi equations, Journal of Computational Physics 223 (2007) 398-415] for the time-dependent Hamilton-Jacobi equations. The causality property of Eikonal equations is incorporated into the design of this solver. The resulting local nonlinear system in the Gauss-Seidel iterations is a simple quadratic system and can be solved explicitly. The compactness of the DG method and the fast sweeping strategy lead to fast convergence of the new scheme for Eikonal equations. Extensive numerical examples verify efficiency, convergence and second order accuracy of the proposed method.

A convergence analysis for a sweeping preconditioner for block tridiagonal systems of linear equations

KAUST Repository

Bagci, Hakan; Pasciak, Joseph E.; Sirenko, Kostyantyn

2014-01-01

We study sweeping preconditioners for symmetric and positive definite block tridiagonal systems of linear equations. The algorithm provides an approximate inverse that can be used directly or in a preconditioned iterative scheme. These algorithms are based on replacing the Schur complements appearing in a block Gaussian elimination direct solve by hierarchical matrix approximations with reduced off-diagonal ranks. This involves developing low rank hierarchical approximations to inverses. We first provide a convergence analysis for the algorithm for reduced rank hierarchical inverse approximation. These results are then used to prove convergence and preconditioning estimates for the resulting sweeping preconditioner.

A convergence analysis for a sweeping preconditioner for block tridiagonal systems of linear equations

KAUST Repository

Bagci, Hakan

2014-11-11

We study sweeping preconditioners for symmetric and positive definite block tridiagonal systems of linear equations. The algorithm provides an approximate inverse that can be used directly or in a preconditioned iterative scheme. These algorithms are based on replacing the Schur complements appearing in a block Gaussian elimination direct solve by hierarchical matrix approximations with reduced off-diagonal ranks. This involves developing low rank hierarchical approximations to inverses. We first provide a convergence analysis for the algorithm for reduced rank hierarchical inverse approximation. These results are then used to prove convergence and preconditioning estimates for the resulting sweeping preconditioner.

Fast backprojection-based reconstruction of spectral-spatial EPR images from projections with the constant sweep of a magnetic field.

Science.gov (United States)

Komarov, Denis A; Hirata, Hiroshi

2017-08-01

In this paper, we introduce a procedure for the reconstruction of spectral-spatial EPR images using projections acquired with the constant sweep of a magnetic field. The application of a constant field-sweep and a predetermined data sampling rate simplifies the requirements for EPR imaging instrumentation and facilitates the backprojection-based reconstruction of spectral-spatial images. The proposed approach was applied to the reconstruction of a four-dimensional numerical phantom and to actual spectral-spatial EPR measurements. Image reconstruction using projections with a constant field-sweep was three times faster than the conventional approach with the application of a pseudo-angle and a scan range that depends on the applied field gradient. Spectral-spatial EPR imaging with a constant field-sweep for data acquisition only slightly reduces the signal-to-noise ratio or functional resolution of the resultant images and can be applied together with any common backprojection-based reconstruction algorithm. Copyright © 2017 Elsevier Inc. All rights reserved.

Study of Near-Stall Flow Behavior in a Modern Transonic Fan with Composite Sweep

Science.gov (United States)

Hah, Chunill; Shin, Hyoun-Woo

2011-01-01

Detailed flow behavior in a modern transonic fan with a composite sweep is investigated in this paper. Both unsteady Reynolds-averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) methods are applied to investigate the flow field over a wide operating range. The calculated flow fields are compared with the data from an array of high-frequency response pressure transducers embedded in the fan casing. The current study shows that a relatively fine computational grid is required to resolve the flow field adequately and to calculate the pressure rise across the fan correctly. The calculated flow field shows detailed flow structure near the fan rotor tip region. Due to the introduction of composite sweep toward the rotor tip, the flow structure at the rotor tip is much more stable compared to that of the conventional blade design. The passage shock stays very close to the leading edge at the rotor tip even at the throttle limit. On the other hand, the passage shock becomes stronger and detaches earlier from the blade passage at the radius where the blade sweep is in the opposite direction. The interaction between the tip clearance vortex and the passage shock becomes intense as the fan operates toward the stall limit, and tip clearance vortex breakdown occurs at near-stall operation. URANS calculates the time-averaged flow field fairly well. Details of measured RMS static pressure are not calculated with sufficient accuracy with URANS. On the other hand, LES calculates details of the measured unsteady flow features in the current transonic fan with composite sweep fairly well and reveals the flow mechanism behind the measured unsteady flow field.

Parallel Sn Sweeps on Unstructured Grids: Algorithms for Prioritization, Grid Partitioning, and Cycle Detection

International Nuclear Information System (INIS)

Plimpton, Steven J.; Hendrickson, Bruce; Burns, Shawn P.; McLendon, William III; Rauchwerger, Lawrence

2005-01-01

The method of discrete ordinates is commonly used to solve the Boltzmann transport equation. The solution in each ordinate direction is most efficiently computed by sweeping the radiation flux across the computational grid. For unstructured grids this poses many challenges, particularly when implemented on distributed-memory parallel machines where the grid geometry is spread across processors. We present several algorithms relevant to this approach: (a) an asynchronous message-passing algorithm that performs sweeps simultaneously in multiple ordinate directions, (b) a simple geometric heuristic to prioritize the computational tasks that a processor works on, (c) a partitioning algorithm that creates columnar-style decompositions for unstructured grids, and (d) an algorithm for detecting and eliminating cycles that sometimes exist in unstructured grids and can prevent sweeps from successfully completing. Algorithms (a) and (d) are fully parallel; algorithms (b) and (c) can be used in conjunction with (a) to achieve higher parallel efficiencies. We describe our message-passing implementations of these algorithms within a radiation transport package. Performance and scalability results are given for unstructured grids with up to 3 million elements (500 million unknowns) running on thousands of processors of Sandia National Laboratories' Intel Tflops machine and DEC-Alpha CPlant cluster

SWEEP, a computer program for the analysis of CDA energetics in liquid metal reactors

International Nuclear Information System (INIS)

Suk, Soo Dong; Lee, Yong Bum; Hahn, Do Hee

2003-12-01

The SWEEP computer code was developed in this study to evaluate the work energy arising from two-phase expansion of fuel or sodium during core disruptive accidents in KALIMER. In the SWEEP program, scoping calculations with a modified Bethe-Tait method is first carried out using SCHAMBETA module to provide the initial thermodynamic conditions for the subsequent analyses to estimate the mechanical work energy generated in the reactor system. To estimate the work energy due to fuel-vapor expansion, a bounding approach is adopted to calculate the work potential assuming isentropic expansion to atmospheric pressure during super-prompt critical power excursions. Work potentials are also calculated in the SWEEP code for sodium expansion using the simple thermodynamic models including the infinite heat transfer model during expansion(Hicks and Menzies method) or more realistic zero heat transfer model for a typical initial condition of core disruptive accident. Core disruptive accidents have been investigated at Korea Atomic Energy Research Institute(KAERI) as part of the work to demonstrate the inherent and ultimate safety of conceptual design of the Korea Advanced Liquid Metal Reactor(KALIMER), a 150 MWe pool-type sodium cooled prototype fast reactor that uses U-TRU-Zr metallic fuel

Wind turbine rotor blade with in-plane sweep and devices using the same, and methods for making the same

Science.gov (United States)

Wetzel, Kyle Kristopher

2014-06-24

A wind turbine includes a rotor having a hub and at least one blade having a torsionally rigid root, an inboard section, and an outboard section. The inboard section has a forward sweep relative to an elastic axis of the blade and the outboard section has an aft sweep.

Beam pinging, sweeping, shaking, and electron/ion collecting, at the Proton Storage Ring

International Nuclear Information System (INIS)

Hardek, T.W.; Macek, R.J.; Plum, M.A.; Wang, T.S.F.

1993-01-01

We have built, installed and tested a pinger for use as a general diagnostic at the Los Alamos Proton Storage Ring (PSR). Two 4-m-long parallel-plate electrodes with a plate spacing of 10.2 cm provide kicks of up to 1.1 mrad. A pair of solid-state pulsers may be operated in a single-pulse mode for beam pinging (tune measurements) or in a burst mode at up to 700 kHz pulse rates for beam sweeping. During our 1992 operating period we used the pinger for beam sweeping, for beam shaking, for measuring the tune shift, and we have used it as an ion chamber. Using the pinger as an ion chamber during production conditions has yielded some surprising results

Reverse spontaneous laser line sweeping in ytterbium fiber laser

Czech Academy of Sciences Publication Activity Database

Navrátil, Petr; Peterka, Pavel; Honzátko, Pavel; Kubeček, V.

2017-01-01

Roč. 14, č. 3 (2017), č. článku 035102. ISSN 1612-2011 R&D Projects: GA ČR(CZ) GA16-13306S Institutional support: RVO:67985882 ; RVO:68378271 Keywords : laser line sweeping * ytterbium * fiber lasers Subject RIV: BH - Optics, Masers, Lasers; BH - Optics, Masers, Lasers (FZU-D) OBOR OECD: Optics (including laser optics and quantum optics); Optics (including laser optics and quantum optics) (FZU-D) Impact factor: 2.537, year: 2016

Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

Science.gov (United States)

Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang

2003-03-01

The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

Vertical-horizontal wells for depletion and sweep

Energy Technology Data Exchange (ETDEWEB)

Muraikhi, A. J.; Pham, T. R.; Liu, J. S.; Khatib, M. R.; Muhaish, A. S. [Saudi Aramco (Saudi Arabia)

1998-12-31

A well completion scheme currently in use in a thick, large, elongated carbonate anticline Middle-East oil reservoir is described. This method of well completion calls for a combination of an open hole horizontal section penetrating the top 10 feet of the reservoir and a cased or undisturbed vertical segment through the thick formation. The horizontal section is used for producing and the vertical segment is used for monitoring purposes. Field experience and supported reservoir simulation exercises have shown that the horizontal application is superior to conventional vertical completion both from the economic and from the sweep point of view. 4 refs., 12 figs.

The Grid[Way] Job Template Manager, a tool for parameter sweeping

Science.gov (United States)

Lorca, Alejandro; Huedo, Eduardo; Llorente, Ignacio M.

2011-04-01

Parameter sweeping is a widely used algorithmic technique in computational science. It is specially suited for high-throughput computing since the jobs evaluating the parameter space are loosely coupled or independent. A tool that integrates the modeling of a parameter study with the control of jobs in a distributed architecture is presented. The main task is to facilitate the creation and deletion of job templates, which are the elements describing the jobs to be run. Extra functionality relies upon the GridWay Metascheduler, acting as the middleware layer for job submission and control. It supports interesting features like multi-dimensional sweeping space, wildcarding of parameters, functional evaluation of ranges, value-skipping and job template automatic indexation. The use of this tool increases the reliability of the parameter sweep study thanks to the systematic bookkeeping of job templates and respective job statuses. Furthermore, it simplifies the porting of the target application to the grid reducing the required amount of time and effort. Program summaryProgram title: Grid[Way] Job Template Manager (version 1.0) Catalogue identifier: AEIE_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIE_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Apache license 2.0 No. of lines in distributed program, including test data, etc.: 3545 No. of bytes in distributed program, including test data, etc.: 126 879 Distribution format: tar.gz Programming language: Perl 5.8.5 and above Computer: Any (tested on PC x86 and x86_64) Operating system: Unix, GNU/Linux (tested on Ubuntu 9.04, Scientific Linux 4.7, centOS 5.4), Mac OS X (tested on Snow Leopard 10.6) RAM: 10 MB Classification: 6.5 External routines: The GridWay Metascheduler [1]. Nature of problem: To parameterize and manage an application running on a grid or cluster. Solution method: Generation of job templates as a cross product of

Stability and transition on swept wings

Science.gov (United States)

Stuckert, Greg; Herbert, Thorwald; Esfahanian, Vahid

1993-01-01

This paper describes the extension and application of the Parabolized Stability Equations (PSE) to the stability and transition of the supersonic three-dimensional laminar boundary layer on a swept wing. The problem formulation uses a general coordinate transformation for arbitrary curvilinear body-fitted computational grids. Some testing using these coordinates is briefly described to help validate the software used for the investigation. The disturbance amplitude ratios as a function of chord position for supersonic (Mach 1.5) boundary layers on untapered, untwisted wings of different sweep angles are then presented and compared with those obtained from local parallel analyses.

From sweeping to the caress: similarities and discrepancies between human and non-human primates' pleasant touch

Directory of Open Access Journals (Sweden)

Laura Clara Grandi

2016-09-01

Full Text Available Affective touch plays a key role in affiliative behavior, offering a mechanism for the formation and maintenance of social bonds among conspecifics, both in humans and non-human primates. Furthermore, it has been speculated that the CT fiber system is a specific coding channel for affiliative touch that occurs during skin-to-skin interactions with conspecifics. In humans, this touch is commonly referred to as the caress, and its correlation with the CT fiber system has been widely demonstrated. It has been hypothesized that the sweeping touch that occurs during grooming in non-human primates may modulate the CT fibers, with recent preliminary studies on rhesus monkeys supporting this hypothesis. The present mini-review proposes a comparison between the pleasant touch, caress and sweeping of humans and non-human primates, respectively. The currently available data was therefore reviewed regarding i the correlation between pleasant touch and CT fibers both in humans and non-human primates, ii the autonomic effects, iii the encoding at the central nervous system, iv the development from early life to adulthood, and v the potential applications of pleasant touch in the daily lives of both humans and non-human primates. Moreover, by considering both the similarities and discrepancies between the human caress and non-human primate sweeping, a possible evolutionary mechanism can be proposed that has developed from sweeping as a utilitarian action with affiliative meaning among monkeys, to the caress as a purely affective gesture associated with humans.

Lipschitz continuous data dependence of sweeping processes in BV spaces

Czech Academy of Sciences Publication Activity Database

Krejčí, Pavel; Roche, T.

2011-01-01

Roč. 15, č. 3 (2011), s. 637-650 ISSN 1531-3492 R&D Projects: GA ČR GAP201/10/2315; GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : rate independence * discontinuous sweeping process * Kurzweil integral Subject RIV: BA - General Mathematics Impact factor: 0.921, year: 2011 http://aimsciences.org/journals/pdfs.jsp?paperID=5943&mode=full

Modeling the Oil Transition: A Summary of the Proceedings of the DOE/EPA Workshop on the Economic and Environmental Implications of Global Energy Transitions

Energy Technology Data Exchange (ETDEWEB)

Greene, David L [ORNL

2007-02-01

The global energy system faces sweeping changes in the next few decades, with potentially critical implications for the global economy and the global environment. It is important that global institutions have the tools necessary to predict, analyze and plan for such massive change. This report summarizes the proceedings of an international workshop concerning methods of forecasting, analyzing, and planning for global energy transitions and their economic and environmental consequences. A specific case, it focused on the transition from conventional to unconventional oil and other energy sources likely to result from a peak in non-OPEC and/or global production of conventional oil. Leading energy models from around the world in government, academia and the private sector met, reviewed the state-of-the-art of global energy modeling and evaluated its ability to analyze and predict large-scale energy transitions.

Small-scale spatial variability of phenoxy acid mineralization potentials in transition zones with a multidisciplinary approach

DEFF Research Database (Denmark)

Pazarbasi, Meric Batioglu

The phenoxy acid group of herbicides is widely used to control broadleaf weeds, and it contaminates groundwater and surface water by leaching from agricultural soil or landfills. Due to the distinct vertical and horizontal gradients in nutrients and hydrologic exchange in transition zones...... in two transition zones, (1) the interfaces of unsaturated and saturated zones and (2) groundwater and surface water. Small-scale spatial variability of phenoxy acids was previously shown in topsoil; however, such small-scale studies are scarce in subsurface environments. We therefore studied the factors...... classes in the different mineralization potentials of discharge zones. Understanding of the natural attenuation potential of groundwater-surface water transition zones is important for stream water protection. In landfill-impacted groundwater-surface water interface, we further analyzed bacterial...

The transition matrix element Agq(N) of the variable flavor number scheme at O(α3s)

International Nuclear Information System (INIS)

Ablinger, J.; Hasselhuhn, A.; Schneider, C.; Manteuffel, A. von

2014-01-01

We calculate the massive operator matrix element A (3) gq (N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This is the first complete transition function needed in the variable flavor number scheme obtained at O(α 3 s ). A fist independent recalculation is performed for the contributions ∝ N F of the 3-loop anomalous dimension γ (2) gq (N).

The transition matrix element Agq(N) of the variable flavor number scheme at O(αs3)

International Nuclear Information System (INIS)

Ablinger, J.; Blümlein, J.; De Freitas, A.; Hasselhuhn, A.; Manteuffel, A. von; Round, M.; Schneider, C.; Wißbrock, F.

2014-01-01

We calculate the massive unpolarized operator matrix element A gq (3) (N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This is the first complete transition function needed in the variable flavor number scheme obtained at O(α s 3 ). A first independent recalculation is performed for the contributions ∝N F of the 3-loop anomalous dimension γ gq (2) (N)

Magnetic Field Diagnostics and Spatio-Temporal Variability of the Solar Transition Region

Science.gov (United States)

Peter, H.

2013-12-01

Magnetic field diagnostics of the transition region from the chromosphere to the corona faces us with the problem that one has to apply extreme-ultraviolet (EUV) spectro-polarimetry. While for the coronal diagnostics techniques already exist in the form of infrared coronagraphy above the limb and radio observations on the disk, one has to investigate EUV observations for the transition region. However, so far the success of such observations has been limited, but various current projects aim to obtain spectro-polarimetric data in the extreme UV in the near future. Therefore it is timely to study the polarimetric signals we can expect from these observations through realistic forward modeling. We employ a 3D magneto-hydrodynamic (MHD) forward model of the solar corona and synthesize the Stokes I and Stokes V profiles of C iv (1548 Å). A signal well above 0.001 in Stokes V can be expected even if one integrates for several minutes to reach the required signal-to-noise ratio, and despite the rapidly changing intensity in the model (just as in observations). This variability of the intensity is often used as an argument against transition region magnetic diagnostics, which requires exposure times of minutes. However, the magnetic field is evolving much slower than the intensity, and therefore the degree of (circular) polarization remains rather constant when one integrates in time. Our study shows that it is possible to measure the transition region magnetic field if a polarimetric accuracy on the order of 0.001 can be reached, which we can expect from planned instrumentation.

Performance of the SWEEP model affected by estimates of threshold friction velocity

Science.gov (United States)

The Wind Erosion Prediction System (WEPS) is a process-based model and needs to be verified under a broad range of climatic, soil, and management conditions. Occasional failure of the WEPS erosion submodel (Single-event Wind Erosion Evaluation Program or SWEEP) to simulate erosion in the Columbia Pl...

Variability in soil CO2 production and surface CO2 efflux across riparian-hillslope transitions

Science.gov (United States)

Vincent Jerald. Pacific

2007-01-01

The spatial and temporal controls on soil CO2 production and surface CO2 efflux have been identified as an outstanding gap in our understanding of carbon cycling. I investigated both the spatial and temporal variability of soil CO2 concentrations and surface CO2 efflux across eight topographically distinct riparian-hillslope transitions in the ~300 ha subalpine upper-...

Acetate and phosphate anion adsorption linear sweep voltammograms simulated using density functional theory

KAUST Repository

Savizi, Iman Shahidi Pour; Janik, Michael J.

2011-01-01

) electrode potential. Four models of the electrode potential are used including a simple vacuum slab model, an applied electric field model with and without the inclusion of a solvating water bi-layer, and the double reference model. The linear sweep

Combustion systems and power plants incorporating parallel carbon dioxide capture and sweep-based membrane separation units to remove carbon dioxide from combustion gases

Science.gov (United States)

Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

2011-10-11

Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.

Gas separation process using membranes with permeate sweep to remove CO.sub.2 from gaseous fuel combustion exhaust

Science.gov (United States)

Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

2012-05-15

A gas separation process for treating exhaust gases from the combustion of gaseous fuels, and gaseous fuel combustion processes including such gas separation. The invention involves routing a first portion of the exhaust stream to a carbon dioxide capture step, while simultaneously flowing a second portion of the exhaust gas stream across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas back to the combustor.

Cross-calibrating Spatial Positions of Light-viewing Diagnostics using Plasma Edge Sweeps in DIII-D

International Nuclear Information System (INIS)

Solomon, W.M.; Burrell, K.H.; Gohil, P.; Groebner, R.; Kaplan, D.

2003-01-01

An experimental technique is presented that permits diagnostics viewing light from the plasma edge to be spatially calibrated relative to one another. By sweeping the plasma edge, each chord of each diagnostic sweeps out a portion of the light emission profile. A nonlinear least-squares fit to such data provides superior cross-calibration of diagnostics located at different toroidal locations compared with simple surveying. Another advantage of the technique is that it can be used to monitor the position of viewing chords during an experimental campaign to ensure that alignment does not change over time. Moreover, should such a change occur, the data can still be cross-calibrated and its usefulness retained

Initial tests of the dual-sweep streak camera system planned for APS particle-beam diagnostics

International Nuclear Information System (INIS)

Lumpkin, A.; Yang, B.; Gai, W.; Cieslik, W.

1995-01-01

Initial tests of a dual-sweep streak system planned for use on the Advanced Photon Source (APS) have been performed using assets of the Argonne Wakefield Accelerator (AWA) facility. The short light pulses from the photoelectric injector drive laser in both the visible (λ=496 nm, Δt∼1.5 ps (FWHM)), and the ultraviolet (λ=248 nm, Δt∼5 ps (FWHM)) were used. Both a UV-visible S20 photocathode streak tube and a UV-to-x-ray Au photocathode streak tube were tested. Calibration data with an etalon were also obtained. A sample of dual-sweep streak data using optical synchrotron radiation on the APS injector synchrotron is also presented

Spall behaviors of high purity copper under sweeping detonation

Energy Technology Data Exchange (ETDEWEB)

Yang, Yang, E-mail: yangyanggroup@163.com [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China); National Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Key Laboratory of Nonferrous Metals Material Science and Engineering of Ministry of Education, Central South University, Changsha 410083 (China); Zhi-qiang, Peng; Xing-zhi, Chen [School of Material Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metals Material Science and Engineering of Ministry of Education, Central South University, Changsha 410083 (China); Zhao-liang, Guo; Tie-gang, Tang; Hai-bo, Hu [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China); Qing-ming, Zhang [National Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

2016-01-10

Suites of sweeping detonation experiments were conducted to assess the spall behavior of high purity copper samples with different heat treatment histories. Incipient spall samples were obtained at different sweeping detonation condition. Metallographic and Electron Backscattered Diffraction (EBSD) analyses were performed on the soft-recovered samples. The effects of grain boundaries, grain size, crystal orientation and loading direction on the spall behaviors were discussed. Spall plane branching was found in the main spall plane of the damage samples. For similar microstructure, the area of voids increase with the increase of shock stress, and the coalescence of voids also become more obvious. Results from EBSD analysis show that the grain sizes were decreased and the grains were elongated along the direction of the plate width. Triple junctions composed of two or more general high angle boundaries are the preferred locations for intergranular damage. Voids prefer to nucleate in the grain boundaries composed of grain with high Taylor Factor (TF) than other grains. The damage areas in the grains with high TF are more severe. Boundaries close to perpendicular to the loading direction are more susceptible to void nucleation than the boundaries close to parallel to the loading direction, but the difference of voids nucleated in these two boundaries is less significant than the results obtained by plate impact experiment. It would be caused by the obliquity between the shock loading direction and the plate normal.

Phylogeography of Nasonia vitripennis (Hymenoptera) indicates a mitochondrial-Wolbachia sweep in North America

NARCIS (Netherlands)

Raychoudhury, R.; Grillenberger, B. K.; Gadau, J.; Bijlsma, R.; van de Zande, L.; Werren, J. H.; Beukeboom, L. W.

Here we report evidence of a mitochondrial-Wolbachia sweep in North American populations of the parasitoid wasp Nasonia vitripennis, a cosmopolitan species and emerging model organism for evolutionary and genetic studies. Analysis of the genetic variation of 89 N. vitripennis specimens from Europe

On the effects of nonlinearities in room impulse response measurements with exponential sweeps

DEFF Research Database (Denmark)

Ciric, Dejan; Markovic, Milos; Mijic, Miomir

2013-01-01

In room impulse response measurements, there are some common disturbances that affect the measured results. These disturbances include nonlinearity, noise and time variance. In this paper, the effects of nonlinearities in the measurements with exponential sweep-sine signals are analyzed from diff...

XO-2b: A HOT JUPITER WITH A VARIABLE HOST STAR THAT POTENTIALLY AFFECTS ITS MEASURED TRANSIT DEPTH

International Nuclear Information System (INIS)

Zellem, Robert T.; Griffith, Caitlin A.; Pearson, Kyle A.; Fitzpatrick, M. Ryleigh; Teske, Johanna K.; Biddle, Lauren I.; Turner, Jake D.; Henry, Gregory W.; Williamson, Michael H.

2015-01-01

The transiting hot Jupiter XO-2b is an ideal target for multi-object photometry and spectroscopy as it has a relatively bright (V-mag = 11.25) K0V host star (XO-2N) and a large planet-to-star contrast ratio (R p /R s ≈ 0.015). It also has a nearby (31.″21) binary stellar companion (XO-2S) of nearly the same brightness (V-mag = 11.20) and spectral type (G9V), allowing for the characterization and removal of shared systematic errors (e.g., airmass brightness variations). We have therefore conducted a multiyear (2012–2015) study of XO-2b with the University of Arizona’s 61″ (1.55 m) Kuiper Telescope and Mont4k CCD in the Bessel U and Harris B photometric passbands to measure its Rayleigh scattering slope to place upper limits on the pressure-dependent radius at, e.g., 10 bar. Such measurements are needed to constrain its derived molecular abundances from primary transit observations. We have also been monitoring XO-2N since the 2013–2014 winter season with Tennessee State University’s Celestron-14 (0.36 m) automated imaging telescope to investigate stellar variability, which could affect XO-2b’s transit depth. Our observations indicate that XO-2N is variable, potentially due to cool star spots, with a peak-to-peak amplitude of 0.0049 ± 0.0007 R-mag and a period of 29.89 ± 0.16 days for the 2013–2014 observing season and a peak-to-peak amplitude of 0.0035 ± 0.0007 R-mag and 27.34 ± 0.21 day period for the 2014–2015 observing season. Because of the likely influence of XO-2N’s variability on the derivation of XO-2b’s transit depth, we cannot bin multiple nights of data to decrease our uncertainties, preventing us from constraining its gas abundances. This study demonstrates that long-term monitoring programs of exoplanet host stars are crucial for understanding host star variability

Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation.

Science.gov (United States)

Hefferman, Gerald; Chen, Zhen; Wei, Tao

2017-07-01

This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation

Science.gov (United States)

Hefferman, Gerald; Chen, Zhen; Wei, Tao

2017-07-01

This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

Sensitive Detection of Organophosphorus Pesticides in Medicinal Plants Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Combined with Sweeping Micellar Electrokinetic Chromatography.

Science.gov (United States)

Wei, Jin-Chao; Hu, Ji; Cao, Ji-Liang; Wan, Jian-Bo; He, Cheng-Wei; Hu, Yuan-Jia; Hu, Hao; Li, Peng

2016-02-03

A simple, rapid, and sensitive method using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) combined with sweeping micellar electrokinetic chromatography (sweeping-MEKC) has been developed for the determination of nine organophosphorus pesticides (chlorfenvinphos, parathion, quinalphos, fenitrothion, azinphos-ethyl, parathion-methyl, fensulfothion, methidathion, and paraoxon). The important parameters that affect the UA-DLLME and sweeping efficiency were investigated. Under the optimized conditions, the proposed method provided 779.0-6203.5-fold enrichment of the nine pesticides compared to the normal MEKC method. The limits of detection ranged from 0.002 to 0.008 mg kg(-1). The relative standard deviations of the peak area ranged from 1.2 to 6.5%, indicating the good repeatability of the method. Finally, the developed UA-DLLME-sweeping-MEKC method has been successfully applied to the analysis of the investigated pesticides in several medicinal plants, including Lycium chinense, Dioscorea opposite, Codonopsis pilosula, and Panax ginseng, indicating that this method is suitable for the determination of trace pesticide residues in real samples with complex matrices.

Comparison of measured and simulated friction velocity and threshold friction velocity using SWEEP

Science.gov (United States)

The Wind Erosion Prediction System (WEPS) was developed by the USDA Agricultural Research Service as a tool to predict wind erosion and assess the influence of control practices on windblown soil loss. Occasional failure of the WEPS erosion submodel (SWEEP) to simulate erosion in the Columbia Platea...

Variable-temperature Microwave Impedance Microscope with Light Stimulation for Research on Photo-induced Phase Transitions

Science.gov (United States)

2017-07-24

SECURITY CLASSIFICATION OF: The DURIP program "Variable-temperature Microwave Impedance Microscope with Light Stimulation for Research on Photo... Stimulation for Research on Photo- induced Phase Transitions The views, opinions and/or findings contained in this report are those of the author(s) and should...reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions

1 μs broadband frequency sweeping reflectometry for plasma density and fluctuation profile measurements

Science.gov (United States)

Clairet, F.; Bottereau, C.; Medvedeva, A.; Molina, D.; Conway, G. D.; Silva, A.; Stroth, U.; ASDEX Upgrade Team; Tore Supra Team; Eurofusion Mst1 Team

2017-11-01

Frequency swept reflectometry has reached the symbolic value of 1 μs sweeping time; this performance has been made possible, thanks to an improved control of the ramp voltage driving the frequency source. In parallel, the memory depth of the acquisition system has been upgraded and can provide up to 200 000 signals during a plasma discharge. Additional improvements regarding the trigger delay determination of the acquisition and the voltage ramp linearity required by this ultra-fast technique have been set. While this diagnostic is traditionally dedicated to the plasma electron density profile measurement, such a fast sweeping rate can provide the study of fast plasma events and turbulence with unprecedented time and radial resolution from the edge to the core. Experimental results obtained on ASDEX Upgrade plasmas are presented to demonstrate the performances of the diagnostic.

Wingbeat frequency-sweep and visual stimuli for trapping male Aedes aegypti (Diptera: Culicidae)

Science.gov (United States)

Combinations of female wingbeat acoustic cues and visual cues were evaluated to determine their potential for use in male Aedes aegypti (L.) traps in peridomestic environments. A modified Centers for Disease control (CDC) light trap using a 350-500 Hz frequency-sweep broadcast from a speaker as an a...

Soft sweeps III: the signature of positive selection from recurrent mutation.

Directory of Open Access Journals (Sweden)

Pleuni S Pennings

2006-12-01

Full Text Available Polymorphism data can be used to identify loci at which a beneficial allele has recently gone to fixation, given that an accurate description of the signature of selection is available. In the classical model that is used, a favored allele derives from a single mutational origin. This ignores the fact that beneficial alleles can enter a population recurrently by mutation during the selective phase. In this study, we present a combination of analytical and simulation results to demonstrate the effect of adaptation from recurrent mutation on summary statistics for polymorphism data from a linked neutral locus. We also analyze the power of standard neutrality tests based on the frequency spectrum or on linkage disequilibrium (LD under this scenario. For recurrent beneficial mutation at biologically realistic rates, we find substantial deviations from the classical pattern of a selective sweep from a single new mutation. Deviations from neutrality in the level of polymorphism and in the frequency spectrum are much less pronounced than in the classical sweep pattern. In contrast, for levels of LD, the signature is even stronger if recurrent beneficial mutation plays a role. We suggest a variant of existing LD tests that increases their power to detect this signature.

XO-2b: A HOT JUPITER WITH A VARIABLE HOST STAR THAT POTENTIALLY AFFECTS ITS MEASURED TRANSIT DEPTH

Energy Technology Data Exchange (ETDEWEB)

Zellem, Robert T.; Griffith, Caitlin A. [Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, University of Arizona, Tucson, AZ 85721 (United States); Pearson, Kyle A.; Fitzpatrick, M. Ryleigh; Teske, Johanna K.; Biddle, Lauren I. [Department of Astronomy, Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Turner, Jake D. [Department of Planetary Sciences, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Henry, Gregory W.; Williamson, Michael H., E-mail: rzellem@lpl.arizona.edu, E-mail: griffith@lpl.arizona.edu [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., P.O. Box 9501, Nashville, TN 37209 (United States)

2015-09-01

The transiting hot Jupiter XO-2b is an ideal target for multi-object photometry and spectroscopy as it has a relatively bright (V-mag = 11.25) K0V host star (XO-2N) and a large planet-to-star contrast ratio (R{sub p}/R{sub s} ≈ 0.015). It also has a nearby (31.″21) binary stellar companion (XO-2S) of nearly the same brightness (V-mag = 11.20) and spectral type (G9V), allowing for the characterization and removal of shared systematic errors (e.g., airmass brightness variations). We have therefore conducted a multiyear (2012–2015) study of XO-2b with the University of Arizona’s 61″ (1.55 m) Kuiper Telescope and Mont4k CCD in the Bessel U and Harris B photometric passbands to measure its Rayleigh scattering slope to place upper limits on the pressure-dependent radius at, e.g., 10 bar. Such measurements are needed to constrain its derived molecular abundances from primary transit observations. We have also been monitoring XO-2N since the 2013–2014 winter season with Tennessee State University’s Celestron-14 (0.36 m) automated imaging telescope to investigate stellar variability, which could affect XO-2b’s transit depth. Our observations indicate that XO-2N is variable, potentially due to cool star spots, with a peak-to-peak amplitude of 0.0049 ± 0.0007 R-mag and a period of 29.89 ± 0.16 days for the 2013–2014 observing season and a peak-to-peak amplitude of 0.0035 ± 0.0007 R-mag and 27.34 ± 0.21 day period for the 2014–2015 observing season. Because of the likely influence of XO-2N’s variability on the derivation of XO-2b’s transit depth, we cannot bin multiple nights of data to decrease our uncertainties, preventing us from constraining its gas abundances. This study demonstrates that long-term monitoring programs of exoplanet host stars are crucial for understanding host star variability.

Variable dose rate single-arc IMAT delivered with a constant dose rate and variable angular spacing

International Nuclear Information System (INIS)

Tang, Grace; Earl, Matthew A; Yu, Cedric X

2009-01-01

Single-arc intensity-modulated arc therapy (IMAT) has gained worldwide interest in both research and clinical implementation due to its superior plan quality and delivery efficiency. Single-arc IMAT techniques such as the Varian RapidArc(TM) deliver conformal dose distributions to the target in one single gantry rotation, resulting in a delivery time in the order of 2 min. The segments in these techniques are evenly distributed within an arc and are allowed to have different monitor unit (MU) weightings. Therefore, a variable dose-rate (VDR) is required for delivery. Because the VDR requirement complicates the control hardware and software of the linear accelerators (linacs) and prevents most existing linacs from delivering IMAT, we propose an alternative planning approach for IMAT using constant dose-rate (CDR) delivery with variable angular spacing. We prove the equivalence by converting VDR-optimized RapidArc plans to CDR plans, where the evenly spaced beams in the VDR plan are redistributed to uneven spacing such that the segments with larger MU weighting occupy a greater angular interval. To minimize perturbation in the optimized dose distribution, the angular deviation of the segments was restricted to ≤± 5 deg. This restriction requires the treatment arc to be broken into multiple sectors such that the local MU fluctuation within each sector is reduced, thereby lowering the angular deviation of the segments during redistribution. The converted CDR plans were delivered with a single gantry sweep as in the VDR plans but each sector was delivered with a different value of CDR. For four patient cases, including two head-and-neck, one brain and one prostate, all CDR plans developed with the variable spacing scheme produced similar dose distributions to the original VDR plans. For plans with complex angular MU distributions, the number of sectors increased up to four in the CDR plans in order to maintain the original plan quality. Since each sector was

On gas sweeping from central regions of galaxies with active nuclei

International Nuclear Information System (INIS)

Silich, S.A.; Fomin, P.I.

1980-01-01

A mechanism of gas sweeping by shock waves from central regions of plane galaxies with active nuclei which is connected with the angular moment transfer from a stellar-cloud component to a gas one is considered. It is shown that shock waves are capable to form the observable density profile with the maximum at a distance of some kpc from galaxy centre for the time of the order of 10 9 years

The protection motivation theory within the stages of the transtheoretical model - stage-specific interplay of variables and prediction of exercise stage transitions.

Science.gov (United States)

Lippke, Sonia; Plotnikoff, Ronald C

2009-05-01

Two different theories of health behaviour have been chosen with the aim of theory integration: a continuous theory (protection motivation theory, PMT) and a stage model (transtheoretical model, TTM). This is the first study to test whether the stages of the TTM moderate the interrelation of PMT-variables and the mediation of motivation, as well as PMT-variables' interactions in predicting stage transitions. Hypotheses were tested regarding (1) mean patterns, stage pair-comparisons and nonlinear trends using ANOVAs; (2) prediction-patterns for the different stage groups employing multi-group structural equation modelling (MSEM) and nested model analyses; and (3) stage transitions using binary logistic regression analyses. Adults (N=1,602) were assessed over a 6 month period on their physical activity stages, PMT-variables and subsequent behaviour. (1) Particular mean differences and nonlinear trends in all test variables were found. (2) The PMT adequately fitted the five stage groups. The MSEM revealed that covariances within threat appraisal and coping appraisal were invariant and all other constrains were stage-specific, i.e. stage was a moderator. Except for self-efficacy, motivation fully mediated the relationship between the social-cognitive variables and behaviour. (3) Predicting stage transitions with the PMT-variables underscored the importance of self-efficacy. Only when threat appraisal and coping appraisal were high, stage movement was more likely in the preparation stage. Results emphasize stage-specific differences of the PMT mechanisms, and hence, support the stage construct. The findings may guide further theory building and research integrating different theoretical approaches.

Influence of sweeping detonation-wave loading on damage evolution during spallation loading of tantalum in both a planar and curved geometry

Energy Technology Data Exchange (ETDEWEB)

Gray, George Thompson III [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hull, Lawrence Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Livescu, Veronica [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Faulkner, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Briggs, Matthew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Meyer, Ross Keith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Andrews, Heather Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hare, Steven John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jakulewicz, Micah Shawn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shinas, Michael A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-03-30

Widespread research over the past five decades has provided a wealth of experimental data and insight concerning the shock hardening, damage evolution, and the spallation response of materials subjected to square-topped shock-wave loading profiles. However, fewer quantitative studies have been conducted on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (unsupported shocks) loading on the shock hardening, damage evolution, or spallation response of materials. Systematic studies quantifying the effect of sweeping-detonation wave loading are yet sparser. In this study, the damage evolution and spallation response of Ta is shown to be critically dependent on the peak shock stress, the geometry of the sample (flat or curved plate geometry), and the shock obliquity during sweeping-detonation-wave shock loading. Sweepingwave loading in the flat-plate geometry is observed to: a) yield a lower spall strength than previously documented for 1-D supported-shock-wave loading, b) exhibit increased shock hardening as a function of increasing obliquity, and c) lead to an increased incidence of deformation twin formation with increasing shock obliquity. Sweeping-wave loading of a 10 cm radius curved Ta plate is observed to: a) lead to an increase in the shear stress as a function of increasing obliquity, b) display a more developed level of damage evolution, extensive voids and coalescence, and lower spall strength with obliquity in the curved plate than seen in the flat-plate sweeping-detonation wave loading for an equivalent HE loading, and c) no increased propensity for deformation twin formation with increasing obliquity as seen in the flat-plate geometry. The overall observations comparing and contrasting the flat versus curved sweeping-wave spall experiments with 1D loaded spallation behavior suggests a coupled influence of obliquity and geometry on dynamic shock-induced damage evolution and spall strength. Coupled experimental and modeling research

Lack of Critical Slowing Down Suggests that Financial Meltdowns Are Not Critical Transitions, yet Rising Variability Could Signal Systemic Risk

Science.gov (United States)

Hoarau, Quentin

2016-01-01

Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms. PMID:26761792

Use of exhaust gas as sweep flow to enhance air separation membrane performance

Science.gov (United States)

Dutart, Charles H.; Choi, Cathy Y.

2003-01-01

An intake air separation system for an internal combustion engine is provided with purge gas or sweep flow on the permeate side of separation membranes in the air separation device. Exhaust gas from the engine is used as a purge gas flow, to increase oxygen flux in the separation device without increasing the nitrogen flux.

Distinguishing between Selective Sweeps from Standing Variation and from a De Novo Mutation

Science.gov (United States)

Peter, Benjamin M.; Huerta-Sanchez, Emilia; Nielsen, Rasmus

2012-01-01

An outstanding question in human genetics has been the degree to which adaptation occurs from standing genetic variation or from de novo mutations. Here, we combine several common statistics used to detect selection in an Approximate Bayesian Computation (ABC) framework, with the goal of discriminating between models of selection and providing estimates of the age of selected alleles and the selection coefficients acting on them. We use simulations to assess the power and accuracy of our method and apply it to seven of the strongest sweeps currently known in humans. We identify two genes, ASPM and PSCA, that are most likely affected by selection on standing variation; and we find three genes, ADH1B, LCT, and EDAR, in which the adaptive alleles seem to have swept from a new mutation. We also confirm evidence of selection for one further gene, TRPV6. In one gene, G6PD, neither neutral models nor models of selective sweeps fit the data, presumably because this locus has been subject to balancing selection. PMID:23071458

Distinguishing between selective sweeps from standing variation and from a de novo mutation.

Directory of Open Access Journals (Sweden)

Benjamin M Peter

Full Text Available An outstanding question in human genetics has been the degree to which adaptation occurs from standing genetic variation or from de novo mutations. Here, we combine several common statistics used to detect selection in an Approximate Bayesian Computation (ABC framework, with the goal of discriminating between models of selection and providing estimates of the age of selected alleles and the selection coefficients acting on them. We use simulations to assess the power and accuracy of our method and apply it to seven of the strongest sweeps currently known in humans. We identify two genes, ASPM and PSCA, that are most likely affected by selection on standing variation; and we find three genes, ADH1B, LCT, and EDAR, in which the adaptive alleles seem to have swept from a new mutation. We also confirm evidence of selection for one further gene, TRPV6. In one gene, G6PD, neither neutral models nor models of selective sweeps fit the data, presumably because this locus has been subject to balancing selection.

Field Experience with Sweep Frequency Response Analysis for Power Transformer Diagnosis

OpenAIRE

Ambuj Kumar; Sunil Kumar Singh; Shrikant Singh

2015-01-01

Sweep frequency response analysis has been turning out a powerful tool for investigation of mechanical as well as electrical integration of transformers. In this paper various aspect of practical application of SFRA has been studied. Open circuit and short circuit measurement were done on different phases of high voltage and low voltage winding. A case study was presented for the transformer of rating 31.5 MVA for various frequency ranges. A clear picture was presented fo...

Influence of high-conductivity buffer composition on field-enhanced sample injection coupled to sweeping in CE.

Science.gov (United States)

Anres, Philippe; Delaunay, Nathalie; Vial, Jérôme; Thormann, Wolfgang; Gareil, Pierre

2013-02-01

The aim of this work was to clarify the mechanism taking place in field-enhanced sample injection coupled to sweeping and micellar EKC (FESI-Sweep-MEKC), with the utilization of two acidic high-conductivity buffers (HCBs), phosphoric acid or sodium phosphate buffer, in view of maximizing sensitivity enhancements. Using cationic model compounds in acidic media, a chemometric approach and simulations with SIMUL5 were implemented. Experimental design first enabled to identify the significant factors and their potential interactions. Simulation demonstrates the formation of moving boundaries during sample injection, which originate at the initial sample/HCB and HCB/buffer discontinuities and gradually change the compositions of HCB and BGE. With sodium phosphate buffer, the HCB conductivity increased during the injection, leading to a more efficient preconcentration by staking (about 1.6 times) than with phosphoric acid alone, for which conductivity decreased during injection. For the same injection time at constant voltage, however, a lower amount of analytes was injected with sodium phosphate buffer than with phosphoric acid. Consequently sensitivity enhancements were lower for the whole FESI-Sweep-MEKC process. This is why, in order to maximize sensitivity enhancements, it is proposed to work with sodium phosphate buffer as HCB and to use constant current during sample injection. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Grain boundary sweeping and dissolution effects on fission product behaviour under severe fuel damage accident conditions

International Nuclear Information System (INIS)

Rest, J.

1986-01-01

The theoretical FASTGRASS-VFP model has been used in the interpretation of fission gas, iodine, tellurium, and cesium release from severe-fuel-damage (SFD) tests performed in the PBF reactor in Idaho. A theory of grain boundary sweeping of gas bubbles, gas bubble behavior during fuel liquefaction (destruction of grain boundaries due to formation of a U-rich melt phase), and during U-Zr eutectic melting has been included within the FASTGRASS-VFP formalism. The grain-boundary-sweeping theory considers the interaction between the moving grain boundary and two distinct size classes of bubbles, those on grain faces and on grain edges. The theory of the effects of fuel liquefaction and U-Zr eutectic melting on fission product behaviour considers the migration and coalescence of fission gas bubbles in either molten uranium, or a Zircaloy-Uranium eutectic melt. Results of the analyses demonstrate that intragranular fission product behavior during the tests can be interpreted in terms of a grain-growth/grain-boundary-sweeping mechanism that enhances the flow of fission products from within the grains to the grain boundaries. Whereas fuel liquefaction leads to an enhanced release of fission products in trace-irradiated fuel, the occurrence of fuel liquefaction in normally-irradiated fuel can degrade fission product release. This phenomenon is due in part to reduced gas-bubble mobilities in a viscous medium as compared to vapor transport, and in part to a degradation of grain growth rates and the subsequent decrease in grain-boundary sweeping of intragranular fission products into the liquified lamina. The analysis shows that total UO 2 dissolution due to eutectic melting leads to increased release for both trace-irradiated and normally-irradiated fuel. The FASTGRASS-VFP predictions, measured release rates from the above tests, and previously published release rates are compared and differences between fission product behavior in trace-irradiated and in normally

Quantum phase transition by employing trace distance along with the density matrix renormalization group

International Nuclear Information System (INIS)

Luo, Da-Wei; Xu, Jing-Bo

2015-01-01

We use an alternative method to investigate the quantum criticality at zero and finite temperature using trace distance along with the density matrix renormalization group. It is shown that the average correlation measured by the trace distance between the system block and environment block in a DMRG sweep is able to detect the critical points of quantum phase transitions at finite temperature. As illustrative examples, we study spin-1 XXZ chains with uniaxial single-ion-type anisotropy and the Heisenberg spin chain with staggered coupling and external magnetic field. It is found that the trace distance shows discontinuity at the critical points of quantum phase transition and can be used as an indicator of QPTs

Signatures of positive selection: from selective sweeps at individual loci to subtle allele frequency changes in polygenic adaptation.

Science.gov (United States)

Stephan, Wolfgang

2016-01-01

In the past 15 years, numerous methods have been developed to detect selective sweeps underlying adaptations. These methods are based on relatively simple population genetic models, including one or two loci at which positive directional selection occurs, and one or two marker loci at which the impact of selection on linked neutral variation is quantified. Information about the phenotype under selection is not included in these models (except for fitness). In contrast, in the quantitative genetic models of adaptation, selection acts on one or more phenotypic traits, such that a genotype-phenotype map is required to bridge the gap to population genetics theory. Here I describe the range of population genetic models from selective sweeps in a panmictic population of constant size to evolutionary traffic when simultaneous sweeps at multiple loci interfere, and I also consider the case of polygenic selection characterized by subtle allele frequency shifts at many loci. Furthermore, I present an overview of the statistical tests that have been proposed based on these population genetics models to detect evidence for positive selection in the genome. © 2015 John Wiley & Sons Ltd.

The Change of Planned Happenstance Skills and Its Association with Career-Related Variables during School-to-Work Transition

Science.gov (United States)

Yang, NaYeon; Yaung, Huk; Noh, Hyunkyung; Jang, Sun Hee; Lee, Bora

2017-01-01

The current study examined how planned happenstance skills (i.e., curiosity, flexibility, persistence, optimism, and risk-taking) changed during school-to-work transition and how career-related variables were associated with the initial levels and change rates of planned happenstance skills. In a sample of 307 South Korean college students, all…

Objective quantification of the tinnitus decompensation by synchronization measures of auditory evoked single sweeps.

Science.gov (United States)

Strauss, Daniel J; Delb, Wolfgang; D'Amelio, Roberto; Low, Yin Fen; Falkai, Peter

2008-02-01

Large-scale neural correlates of the tinnitus decompensation might be used for an objective evaluation of therapies and neurofeedback based therapeutic approaches. In this study, we try to identify large-scale neural correlates of the tinnitus decompensation using wavelet phase stability criteria of single sweep sequences of late auditory evoked potentials as synchronization stability measure. The extracted measure provided an objective quantification of the tinnitus decompensation and allowed for a reliable discrimination between a group of compensated and decompensated tinnitus patients. We provide an interpretation for our results by a neural model of top-down projections based on the Jastreboff tinnitus model combined with the adaptive resonance theory which has not been applied to model tinnitus so far. Using this model, our stability measure of evoked potentials can be linked to the focus of attention on the tinnitus signal. It is concluded that the wavelet phase stability of late auditory evoked potential single sweeps might be used as objective tinnitus decompensation measure and can be interpreted in the framework of the Jastreboff tinnitus model and adaptive resonance theory.

Planetesimal formation by sweep-up coagulation

Science.gov (United States)

Windmark, Fredrik; Birnstiel, Til; Ormel, Chris W.; Dullemond, Cornelis P.

2013-07-01

The formation of planetesimals is often accredited to collisional sticking of dust grains in the protoplanetary disk. The exact process is however unknown, as collisions between larger aggregates tend to lead to fragmentation or bouncing rather than sticking. These growth barriers tend to halt the dust growth already at millimeters or centimeters in size, which is far below the kilometer-sizes that are needed for gravity to aid in the accretion. To study how far dust coagulation can proceed, we have developed a new collision model based on the latest laboratory experiments, and have used it together with a dust-size evolution code capable of resolving all grain interactions in the protoplanetary disk. We find that for the general dust population, bouncing and fragmenting collisions prevent the growth above millimeter-sizes. However, a small number of lucky particles can grow larger than the rest by only interacting at low, sticky velocities. As they grow, they become increasingly resilient to fragmentation caused by the small grains. In this way, two populations are formed: One which remains small due to the collisional barriers, and one that continues to grow by sweeping up the smaller grains around them.

Topography of sound level representation in the FM sweep selective region of the pallid bat auditory cortex.

Science.gov (United States)

Measor, Kevin; Yarrow, Stuart; Razak, Khaleel A

2018-05-26

Sound level processing is a fundamental function of the auditory system. To determine how the cortex represents sound level, it is important to quantify how changes in level alter the spatiotemporal structure of cortical ensemble activity. This is particularly true for echolocating bats that have control over, and often rapidly adjust, call level to actively change echo level. To understand how cortical activity may change with sound level, here we mapped response rate and latency changes with sound level in the auditory cortex of the pallid bat. The pallid bat uses a 60-30 kHz downward frequency modulated (FM) sweep for echolocation. Neurons tuned to frequencies between 30 and 70 kHz in the auditory cortex are selective for the properties of FM sweeps used in echolocation forming the FM sweep selective region (FMSR). The FMSR is strongly selective for sound level between 30 and 50 dB SPL. Here we mapped the topography of level selectivity in the FMSR using downward FM sweeps and show that neurons with more monotonic rate level functions are located in caudomedial regions of the FMSR overlapping with high frequency (50-60 kHz) neurons. Non-monotonic neurons dominate the FMSR, and are distributed across the entire region, but there is no evidence for amplitopy. We also examined how first spike latency of FMSR neurons change with sound level. The majority of FMSR neurons exhibit paradoxical latency shift wherein the latency increases with sound level. Moreover, neurons with paradoxical latency shifts are more strongly level selective and are tuned to lower sound level than neurons in which latencies decrease with level. These data indicate a clustered arrangement of neurons according to monotonicity, with no strong evidence for finer scale topography, in the FMSR. The latency analysis suggests mechanisms for strong level selectivity that is based on relative timing of excitatory and inhibitory inputs. Taken together, these data suggest how the spatiotemporal

A SEARCH FOR L/T TRANSITION DWARFS WITH Pan-STARRS1 AND WISE: DISCOVERY OF SEVEN NEARBY OBJECTS INCLUDING TWO CANDIDATE SPECTROSCOPIC VARIABLES

International Nuclear Information System (INIS)

Best, William M. J.; Liu, Michael C.; Magnier, Eugene A.; Aller, Kimberly M.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Tonry, J. L.; Wainscoat, R. J.; Deacon, Niall R.; Dupuy, Trent J.; Redstone, Joshua; Price, P. A.

2013-01-01

We present initial results from a wide-field (30,000 deg 2 ) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and Wide-field Infrared Survey Explorer (WISE) surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because these objects are faint in optical bands and have near-infrared (near-IR) colors that are difficult to distinguish from background stars. To overcome these obstacles, we have cross-matched the Pan-STARRS1 (optical) and WISE (mid-IR) catalogs to produce a unique multi-wavelength database for finding ultracool dwarfs. As part of our initial discoveries, we have identified seven brown dwarfs in the L/T transition within 9-15 pc of the Sun. The L9.5 dwarf PSO J140.2308+45.6487 and the T1.5 dwarf PSO J307.6784+07.8263 (both independently discovered by Mace et al.) show possible spectroscopic variability at the Y and J bands. Two more objects in our sample show evidence of photometric J-band variability, and two others are candidate unresolved binaries based on their spectra. We expect our full search to yield a well-defined, volume-limited sample of L/T transition dwarfs that will include many new targets for study of this complex regime. PSO J307.6784+07.8263 in particular may be an excellent candidate for in-depth study of variability, given its brightness (J = 14.2 mag) and proximity (11 pc)

Thermal transients due to sweeping of the separatrix on the monoblock divertor concept for ITER

International Nuclear Information System (INIS)

Renda, V.; Papa, L.; Soria, A.

1991-01-01

The ITER divertor plate considered in the present study is the monoblock design option, consisting of an armour of CFC-SEP-Carb graphite tiles, crossed by the tubes of the water cooling system made in Mo-Re alloy. Preliminary steady-state calculations for a peak flux of 15 MW/m 2 showed that the allowable thickness to limit the maximum temperature to 1273 K (1000degC) is about 5 mm. This small value reduces the lifetime of the plate, due to the expected erosion rate, to an unacceptable value from the engineering standpoint. A sweeping of the separatrix has been proposed to reduce the erosion of the protective armour and to lessen the thermomechanical effects of the localized peak surface heat flux. A rotation of the null points of the separatrix of 30 mm radius with a frequency of 0.3 Hz for a surface heat flux of 15 MW/m 2 was assumed as nominal working condition. Several scenarios were considered as off-normal conditions: the loss of sweeping accident, the change in frequency from 0.3 to 0.1 Hz and the change of the peak of the surface heat flux from 15 to 30 MW/m 2 . The results related to the nominal condition show that a 16 mm thick armour could be allowed; this value should ensure an acceptable lifetime for the divertor plate. The loss of sweeping accident leads the surface temperature to reach about 2273 K in few seconds; the change in frequency raises the maximum temperature of 423 K, but its range doubles; the change in peak flux leads to a maximum temperature of about 2373 K. (author)

Private selective sweeps identified from next-generation pool-sequencing reveal convergent pathways under selection in two inbred Schistosoma mansoni strains.

Directory of Open Access Journals (Sweden)

Julie A J Clément

Full Text Available BACKGROUND: The trematode flatworms of the genus Schistosoma, the causative agents of schistosomiasis, are among the most prevalent parasites in humans, affecting more than 200 million people worldwide. In this study, we focused on two well-characterized strains of S. mansoni, to explore signatures of selection. Both strains are highly inbred and exhibit differences in life history traits, in particular in their compatibility with the intermediate host Biomphalaria glabrata. METHODOLOGY/PRINCIPAL FINDINGS: We performed high throughput sequencing of DNA from pools of individuals of each strain using Illumina technology and identified single nucleotide polymorphisms (SNP and copy number variations (CNV. In total, 708,898 SNPs were identified and roughly 2,000 CNVs. The SNPs revealed low nucleotide diversity (π = 2 × 10(-4 within each strain and a high differentiation level (Fst = 0.73 between them. Based on a recently developed in-silico approach, we further detected 12 and 19 private (i.e. specific non-overlapping selective sweeps among the 121 and 151 sweeps found in total for each strain. CONCLUSIONS/SIGNIFICANCE: Functional annotation of transcripts lying in the private selective sweeps revealed specific selection for functions related to parasitic interaction (e.g. cell-cell adhesion or redox reactions. Despite high differentiation between strains, we identified evolutionary convergence of genes related to proteolysis, known as a key virulence factor and a potential target of drug and vaccine development. Our data show that pool-sequencing can be used for the detection of selective sweeps in parasite populations and enables one to identify biological functions under selection.

Reducing Side-Sweep Accidents with Vehicle-to-Vehicle Communication

Directory of Open Access Journals (Sweden)

Gamini Bulumulle

2016-12-01

Full Text Available Side-sweep accidents are one of the major causes of loss of life and property damage on highways. This type of accident is caused by a driver initiating a lane change while another vehicle is blocking the road in the target lane. In this article, we are trying to quantify the degree to which different implementations of vehicle-to-vehicle (V2V communication could reduce the occurrence of such accidents. We present the design of a simulator that takes into account common sources of lack of driver awareness such as blind-spots and lack of attention. Then, we study the impact of both traditional, non-technological communication means such as turning signals as well as unidirectional and bidirectional V2V communications.

Coordinating Transit Transfers in Real Time

Science.gov (United States)

2016-05-06

Transfers are a major source of travel time variability for transit passengers. Coordinating transfers between transit routes in real time can reduce passenger waiting times and travel time variability, but these benefits need to be contrasted with t...

Spin-Label CW Microwave Power Saturation and Rapid Passage with Triangular Non-Adiabatic Rapid Sweep (NARS) and Adiabatic Rapid Passage (ARP) EPR Spectroscopy

Science.gov (United States)

Kittell, Aaron W.; Hyde, James S.

2015-01-01

Non-adiabatic rapid passage (NARS) electron paramagnetic resonance (EPR) spectroscopy was introduced by Kittell, A.W., Camenisch, T.G., Ratke, J.J. Sidabras, J.W., Hyde, J.S., 2011 as a general purpose technique to collect the pure absorption response. The technique has been used to improve sensitivity relative to sinusoidal magnetic field modulation, increase the range of inter-spin distances that can be measured under near physiological conditions, and enhance spectral resolution in copper (II) spectra. In the present work, the method is extended to CW microwave power saturation of spin-labeled T4 Lysozyme (T4L). As in the cited papers, rapid triangular sweep of the polarizing magnetic field was superimposed on slow sweep across the spectrum. Adiabatic rapid passage (ARP) effects were encountered in samples undergoing very slow rotational diffusion as the triangular magnetic field sweep rate was increased. The paper reports results of variation of experimental parameters at the interface of adiabatic and non-adiabatic rapid sweep conditions. Comparison of the forward (up) and reverse (down) triangular sweeps is shown to be a good indicator of the presence of rapid passage effects. Spectral turning points can be distinguished from spectral regions between turning points in two ways: differential microwave power saturation and differential passage effects. Oxygen accessibility data are shown under NARS conditions that appear similar to conventional field modulation data. However, the sensitivity is much higher, permitting, in principle, experiments at substantially lower protein concentrations. Spectral displays were obtained that appear sensitive to rotational diffusion in the range of rotational correlation times of 10−3 to 10−7 s in a manner that is analogous to saturation transfer spectroscopy. PMID:25917132

Linear sweep polarographic determination of nucleic acids using acridine orange as a bioprobe

Directory of Open Access Journals (Sweden)

WEI SUN

2007-11-01

Full Text Available The interaction of acridine orange (AO with double-stranded (ds DNA in aqueous solution was investigated by linear sweep polarography (LSP on a dropping mercury working electrode (DME. In pH 2.5 Britton–Robinson (B–R buffer solution, AO had a sensitive linear sweep polarographic reductive peak at –0.89 V (vs. SCE, which could be greatly inhibited by the addition of dsDNA, with a positive shift of the peak potential. Based on the decrease of the reductive peak current, a new quantitative electrochemical determination method for dsDNA was developed with a linear range of 2.0−20.0 mg l-1 and the linear regression equation: ΔIp” (nA = 111.90 C (mg l-1+125.32 (n = 9, γ = 0.997. The influences of commonly co-existing substances, such as metal ions, amino acid, etc., on the determination were also investigated. The method is sensitive, rapid and simple with good selectivity. The new proposed method was further applied to the detection of RNA and three synthetic samples containing dsDNA with satisfactory results. The binding number and the equilibrium constant between dsDNA and AO were calculated by an electrochemical method.

Genome-wide Selective Sweeps in Natural Bacterial Populations Revealed by Time-series Metagenomics

Energy Technology Data Exchange (ETDEWEB)

Chan, Leong-Keat; Bendall, Matthew L.; Malfatti, Stephanie; Schwientek, Patrick; Tremblay, Julien; Schackwitz, Wendy; Martin, Joel; Pati, Amrita; Bushnell, Brian; Foster, Brian; Kang, Dongwan; Tringe, Susannah G.; Bertilsson, Stefan; Moran, Mary Ann; Shade, Ashley; Newton, Ryan J.; Stevens, Sarah; McMcahon, Katherine D.; Mamlstrom, Rex R.

2014-05-12

Multiple evolutionary models have been proposed to explain the formation of genetically and ecologically distinct bacterial groups. Time-series metagenomics enables direct observation of evolutionary processes in natural populations, and if applied over a sufficiently long time frame, this approach could capture events such as gene-specific or genome-wide selective sweeps. Direct observations of either process could help resolve how distinct groups form in natural microbial assemblages. Here, from a three-year metagenomic study of a freshwater lake, we explore changes in single nucleotide polymorphism (SNP) frequencies and patterns of gene gain and loss in populations of Chlorobiaceae and Methylophilaceae. SNP analyses revealed substantial genetic heterogeneity within these populations, although the degree of heterogeneity varied considerably among closely related, co-occurring Methylophilaceae populations. SNP allele frequencies, as well as the relative abundance of certain genes, changed dramatically over time in each population. Interestingly, SNP diversity was purged at nearly every genome position in one of the Chlorobiaceae populations over the course of three years, while at the same time multiple genes either swept through or were swept from this population. These patterns were consistent with a genome-wide selective sweep, a process predicted by the ecotype model? of diversification, but not previously observed in natural populations.

Genome-wide Selective Sweeps in Natural Bacterial Populations Revealed by Time-series Metagenomics

Energy Technology Data Exchange (ETDEWEB)

Chan, Leong-Keat; Bendall, Matthew L.; Malfatti, Stephanie; Schwientek, Patrick; Tremblay, Julien; Schackwitz, Wendy; Martin, Joel; Pati, Amrita; Bushnell, Brian; Foster, Brian; Kang, Dongwan; Tringe, Susannah G.; Bertilsson, Stefan; Moran, Mary Ann; Shade, Ashley; Newton, Ryan J.; Stevens, Sarah; McMahon, Katherine D.; Malmstrom, Rex R.

2014-06-18

Multiple evolutionary models have been proposed to explain the formation of genetically and ecologically distinct bacterial groups. Time-series metagenomics enables direct observation of evolutionary processes in natural populations, and if applied over a sufficiently long time frame, this approach could capture events such as gene-specific or genome-wide selective sweeps. Direct observations of either process could help resolve how distinct groups form in natural microbial assemblages. Here, from a three-year metagenomic study of a freshwater lake, we explore changes in single nucleotide polymorphism (SNP) frequencies and patterns of gene gain and loss in populations of Chlorobiaceae and Methylophilaceae. SNP analyses revealed substantial genetic heterogeneity within these populations, although the degree of heterogeneity varied considerably among closely related, co-occurring Methylophilaceae populations. SNP allele frequencies, as well as the relative abundance of certain genes, changed dramatically over time in each population. Interestingly, SNP diversity was purged at nearly every genome position in one of the Chlorobiaceae populations over the course of three years, while at the same time multiple genes either swept through or were swept from this population. These patterns were consistent with a genome-wide selective sweep, a process predicted by the ‘ecotype model’ of diversification, but not previously observed in natural populations.

Cross-polarization phenomena in the NMR of fast spinning solids subject to adiabatic sweeps

Energy Technology Data Exchange (ETDEWEB)

Wi, Sungsool, E-mail: sungsool@magnet.fsu.edu, E-mail: lucio.frydman@weizmann.ac.il; Gan, Zhehong [National High Magnetic Field Laboratory, Tallahassee, Florida 32304 (United States); Schurko, Robert [Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor N9B 3P4, Ontario (Canada); Frydman, Lucio, E-mail: sungsool@magnet.fsu.edu, E-mail: lucio.frydman@weizmann.ac.il [National High Magnetic Field Laboratory, Tallahassee, Florida 32304 (United States); Department of Chemical Physics, Weizmann Institute of Sciences, 76100 Rehovot (Israel)

2015-02-14

Cross-polarization magic-angle spinning (CPMAS) experiments employing frequency-swept pulses are explored within the context of obtaining broadband signal enhancements for rare spin S = 1/2 nuclei at very high magnetic fields. These experiments employ adiabatic inversion pulses on the S-channel ({sup 13}C) to cover a wide frequency offset range, while simultaneously applying conventional spin-locking pulse on the I-channel ({sup 1}H). Conditions are explored where the adiabatic frequency sweep width, Δν, is changed from selectively irradiating a single magic-angle-spinning (MAS) spinning centerband or sideband, to sweeping over multiple sidebands. A number of new physical features emerge upon assessing the swept-CP method under these conditions, including multiple zero- and double-quantum CP transfers happening in unison with MAS-driven rotary resonance phenomena. These were examined using an average Hamiltonian theory specifically designed to tackle these experiments, with extensive numerical simulations, and with experiments on model compounds. Ultrawide CP profiles spanning frequency ranges of nearly 6⋅γB{sub 1}{sup s} were predicted and observed utilizing this new approach. Potential extensions and applications of this extremely broadband transfer conditions are briefly discussed.

Solving the Capacitive Effect in the High-Frequency sweep for Langmuir Probe in SYMPLE

International Nuclear Information System (INIS)

Pramila; Patel, J J; Rajpal, R; Hansalia, C J; Anitha, V P; Sathyanarayana, K

2017-01-01

Langmuir Probe based measurements need to be routinely carried out to measure various plasma parameters such as the electron density (n e ), the electron temperature (T e ), the floating potential (V f ), and the plasma potential (V p ). For this, the diagnostic electronics along with the biasing power supplies is installed in standard industrial racks with a 2KV isolation transformer. The Signal Conditioning Electronics (SCE) system is populated inside the 4U-chassis based system with the front-end electronics, designed using high common mode differential amplifiers which can measure small differential signal in presence of high common mode dc- bias or ac ramp voltage used for biasing the probes. DC-biasing of the probe is most common method for getting its I-V characteristic but method of biasing the probe with a sweep at high frequency encounters the problem of corruption of signal due to capacitive effect specially when the sweep period and the discharge time is very fast and die down in the order of μs or lesser. This paper presents and summarises the method of removing such effects encountered while measuring the probe current. (paper)

Solving the Capacitive Effect in the High-Frequency sweep for Langmuir Probe in SYMPLE

Science.gov (United States)

Pramila; Patel, J. J.; Rajpal, R.; Hansalia, C. J.; Anitha, V. P.; Sathyanarayana, K.

2017-04-01

Langmuir Probe based measurements need to be routinely carried out to measure various plasma parameters such as the electron density (ne), the electron temperature (Te), the floating potential (Vf), and the plasma potential (Vp). For this, the diagnostic electronics along with the biasing power supplies is installed in standard industrial racks with a 2KV isolation transformer. The Signal Conditioning Electronics (SCE) system is populated inside the 4U-chassis based system with the front-end electronics, designed using high common mode differential amplifiers which can measure small differential signal in presence of high common mode dc- bias or ac ramp voltage used for biasing the probes. DC-biasing of the probe is most common method for getting its I-V characteristic but method of biasing the probe with a sweep at high frequency encounters the problem of corruption of signal due to capacitive effect specially when the sweep period and the discharge time is very fast and die down in the order of μs or lesser. This paper presents and summarises the method of removing such effects encountered while measuring the probe current.

The characteristics of void distribution in spalled high purity copper cylinder under sweeping detonation

Science.gov (United States)

Yang, Yang; Jiang, Zhi; Chen, Jixinog; Guo, Zhaoliang; Tang, Tiegang; Hu, Haibo

2018-03-01

The effects of different peak compression stresses (2-5 GPa) on the spallation behaviour of high purity copper cylinder during sweeping detonation were examined by Electron Backscatter Diffraction Microscopy, Doppler Pins System and Optical Microscopy techniques. The velocity history of inner surface and the characteristics of void distributions in spalled copper cylinder were investigated. The results indicated that the spall strength of copper in these experiments was less than that revealed in previous reports concerning plate impact loading. The geometry of cylindrical copper and the obliquity of incident shock during sweeping detonation may be the main reasons. Different loading stresses seemed to be responsible for the characteristics of the resultant damage fields, and the maximum damage degree increased with increasing shock stress. Spall planes in different cross-sections of sample loaded with the same shock stress of 3.29 GPa were found, and the distance from the initiation end has little effect on the maximum damage degree (the maximum damage range from 12 to 14%), which means that the spallation behaviour was stable along the direction parallel to the detonation propagation direction under the same shock stress.

Interactions between oxygen permeation and homogeneous-phase fuel conversion on the sweep side of an ion transport membrane

KAUST Repository

Hong, Jongsup

2013-02-01

The interactions between oxygen permeation and homogeneous fuel oxidation reactions on the sweep side of an ion transport membrane (ITM) are examined using a comprehensive model, which couples the dependency of the oxygen permeation rate on the membrane surface conditions and detailed chemistry and transport in the vicinity of the membrane. We assume that the membrane surface is not catalytic to hydrocarbon or syngas oxidation. Results show that increasing the sweep gas inlet temperature and fuel concentration enhances oxygen permeation substantially. This is accomplished through promoting oxidation reactions (oxygen consumption) and the transport of the products and reaction heat towards the membrane, which lowers the oxygen concentration and increases the gas temperature near the membrane. Faster reactions at higher fuel concentration and higher inlet gas temperature support substantial fuel conversion and lead to a higher oxygen permeation flux without the contribution of surface catalytic activity. Beyond a certain maximum in the fuel concentration, extensive heat loss to the membrane (and feed side) reduces the oxidation kinetic rates and limits oxygen permeation as the reaction front reaches the membrane. The sweep gas flow rate and channel height have moderate impacts on oxygen permeation and fuel conversion due to the residence time requirements for the chemical reactions and the location of the reaction zone relative to the membrane surface. © 2012 Elsevier B.V.

A SEARCH FOR L/T TRANSITION DWARFS WITH Pan-STARRS1 AND WISE: DISCOVERY OF SEVEN NEARBY OBJECTS INCLUDING TWO CANDIDATE SPECTROSCOPIC VARIABLES

Energy Technology Data Exchange (ETDEWEB)

Best, William M. J.; Liu, Michael C.; Magnier, Eugene A.; Aller, Kimberly M.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Tonry, J. L.; Wainscoat, R. J. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Deacon, Niall R. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Dupuy, Trent J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Redstone, Joshua [Facebook, 335 Madison Ave, New York, NY 10017-4677 (United States); Price, P. A., E-mail: wbest@ifa.hawaii.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-11-10

We present initial results from a wide-field (30,000 deg{sup 2}) search for L/T transition brown dwarfs within 25 pc using the Pan-STARRS1 and Wide-field Infrared Survey Explorer (WISE) surveys. Previous large-area searches have been incomplete for L/T transition dwarfs, because these objects are faint in optical bands and have near-infrared (near-IR) colors that are difficult to distinguish from background stars. To overcome these obstacles, we have cross-matched the Pan-STARRS1 (optical) and WISE (mid-IR) catalogs to produce a unique multi-wavelength database for finding ultracool dwarfs. As part of our initial discoveries, we have identified seven brown dwarfs in the L/T transition within 9-15 pc of the Sun. The L9.5 dwarf PSO J140.2308+45.6487 and the T1.5 dwarf PSO J307.6784+07.8263 (both independently discovered by Mace et al.) show possible spectroscopic variability at the Y and J bands. Two more objects in our sample show evidence of photometric J-band variability, and two others are candidate unresolved binaries based on their spectra. We expect our full search to yield a well-defined, volume-limited sample of L/T transition dwarfs that will include many new targets for study of this complex regime. PSO J307.6784+07.8263 in particular may be an excellent candidate for in-depth study of variability, given its brightness (J = 14.2 mag) and proximity (11 pc)

High-sweeping-speed optically synchronized dual-channel terahertz-signal generator for driving a superconducting tunneling mixer and its application to active gas sensing.

Science.gov (United States)

Oh, Kyoung-Hwan; Shimizu, Naofumi; Kohjiro, Satoshi; Kikuchi, Ken'ichi; Wakatsuki, Atsushi; Kukutsu, Naoya; Kado, Yuichi

2009-10-12

We propose a high-sweeping-speed optically synchronized dual-channel terahertz (THz) signal generator for an active gas-sensing system with a superconductor-insulator-superconductor (SIS) mixer. The generator can sweep a frequency range from 200 to 500 GHz at a speed of 375 GHz/s and a frequency resolution of 500 MHz. With the developed gas-sensing system, a gas-absorption-line measurement was successfully carried out with N(2)O gas in that frequency range.

Experimental transonic flutter characteristics of two 72 deg-sweep delta-wing models

Science.gov (United States)

Doggett, Robert V., Jr.; Soistmann, David L.; Spain, Charles V.; Parker, Ellen C.; Silva, Walter A.

1989-01-01

Transonic flutter boundaries are presented for two simple, 72 deg. sweep, low-aspect-ratio wing models. One model was an aspect-ratio 0.65 delta wing; the other model was an aspect-ratio 0.54 clipped-delta wing. Flutter boundaries for the delta wing are presented for the Mach number range of 0.56 to 1.22. Flutter boundaries for the clipped-delta wing are presented for the Mach number range of 0.72 to 0.95. Selected vibration characteristics of the models are also presented.

A TV camera system for digitizing single shot oscillograms at sweep rate of 0.1 ns/cm

International Nuclear Information System (INIS)

Kienlen, M.; Knispel, G.; Miehe, J.A.; Sipp, B.

1976-01-01

A TV camera digitizing system associated with a 5 GHz photocell-oscilloscope apparatus allows the digitizing of single shot oscillograms; with an oscilloscope sweep rate of 0.1 ns/cm an accuracy on time measurements of 4 ps is obtained [fr

An Adaptive Sweep-Circle Spatial Clustering Algorithm Based on Gestalt

Directory of Open Access Journals (Sweden)

Qingming Zhan

2017-08-01

Full Text Available An adaptive spatial clustering (ASC algorithm is proposed in this present study, which employs sweep-circle techniques and a dynamic threshold setting based on the Gestalt theory to detect spatial clusters. The proposed algorithm can automatically discover clusters in one pass, rather than through the modification of the initial model (for example, a minimal spanning tree, Delaunay triangulation, or Voronoi diagram. It can quickly identify arbitrarily-shaped clusters while adapting efficiently to non-homogeneous density characteristics of spatial data, without the need for prior knowledge or parameters. The proposed algorithm is also ideal for use in data streaming technology with dynamic characteristics flowing in the form of spatial clustering in large data sets.

Thermo-mechanical design of a CW sweep plate emittance scanner

International Nuclear Information System (INIS)

Rathke, J.; Peacock, M.; Sredniawski, J.

1996-01-01

A sweep plate emittance scanner for use with high power, continuous wave (CW) beams has been designed, fabricated and commissioned at Northrop Grumman. The design is capable of scanning beams of up to 20 kW beam power with a spot diameter as small as 2 cm. The scanner pod is mounted on a ball screw driven linear bearing table that is driven through the beam by a stepper motor at velocities up to 30 cm/sec. This paper presents the thermo-mechanical analysis of the pod moving through a gaussian beam and the details of the mechanical design of the pod and motion system. Analyses to determine scanner cooling schemes and structural materials are presented. (author)

The transition matrix element A{sub gq}(N) of the variable flavor number scheme at O(α{sub s}{sup 3})

Energy Technology Data Exchange (ETDEWEB)

Ablinger, J. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Blümlein, J.; De Freitas, A. [Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Hasselhuhn, A. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Manteuffel, A. von [PRISMA Cluster of Excellence and Institute of Physics, J. Gutenberg University, D-55099 Mainz (Germany); Round, M. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Schneider, C. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Wißbrock, F. [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz (Austria); Deutsches Elektronen-Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

2014-05-15

We calculate the massive unpolarized operator matrix element A{sub gq}{sup (3)}(N) to 3-loop order in Quantum Chromodynamics at general values of the Mellin variable N. This is the first complete transition function needed in the variable flavor number scheme obtained at O(α{sub s}{sup 3}). A first independent recalculation is performed for the contributions ∝N{sub F} of the 3-loop anomalous dimension γ{sub gq}{sup (2)}(N)

Dealing with selection bias in educational transition models

DEFF Research Database (Denmark)

Holm, Anders; Jæger, Mads Meier

2011-01-01

This paper proposes the bivariate probit selection model (BPSM) as an alternative to the traditional Mare model for analyzing educational transitions. The BPSM accounts for selection on unobserved variables by allowing for unobserved variables which affect the probability of making educational tr...... account for selection on unobserved variables and high-quality data are both required in order to estimate credible educational transition models.......This paper proposes the bivariate probit selection model (BPSM) as an alternative to the traditional Mare model for analyzing educational transitions. The BPSM accounts for selection on unobserved variables by allowing for unobserved variables which affect the probability of making educational...... transitions to be correlated across transitions. We use simulated and real data to illustrate how the BPSM improves on the traditional Mare model in terms of correcting for selection bias and providing credible estimates of the effect of family background on educational success. We conclude that models which...

TRANSITING THE SUN. II. THE IMPACT OF STELLAR ACTIVITY ON Lyα TRANSITS

International Nuclear Information System (INIS)

Llama, J.; Shkolnik, E. L.

2016-01-01

High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure the properties of transiting exoplanets in the presence of stellar activity. Here we insert the transit of a hot Jupiter into continuous disk integrated data of the Sun in Lyα from NASA’s Solar Dynamics Observatory/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio (R p /R ⋆ ). In 75% of our simulated light curves, we measure the correct radius ratio; however, incorrect values can be measured if there is significant short-term variability in the light curve. The maximum measured value of R p /R ⋆ is 50% larger than the input value, which is much smaller than the large Lyα transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations without a transit and found that stellar activity cannot mimic the Lyα transit of 55 Cancari b, strengthening the conclusion that this planet has a partially transiting exopshere. We were able to compare our simulations to more active stars by artificially increasing the variability in the Solar Lyα light curve. In the higher variability data, the largest value of R p /R ⋆ we measured is <3× the input value, which again is not large enough to reproduce the Lyα transit depth reported for the more active stars HD 189733 and GJ 436, supporting the interpretation that these planets have extended atmospheres and possible cometary tails

Improving the sweeping efficiency of permanganate into low permeable zones to treat TCE: experimental results and model development.

Science.gov (United States)

Chokejaroenrat, Chanat; Kananizadeh, Negin; Sakulthaew, Chainarong; Comfort, Steve; Li, Yusong

2013-11-19

The residual buildup and treatment of dissolved contaminants in low permeable zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate into LPZs to treat dissolved-phase TCE. This was accomplished by conducting transport experiments that quantified the ability of xanthan-MnO4(-) solutions to penetrate and cover (i.e., sweep) an LPZ that was surrounded by transmissive sands. By incorporating the non-Newtonian fluid xanthan with MnO4(-), penetration of MnO4(-) into the LPZ improved dramatically and sweeping efficiency reached 100% in fewer pore volumes. To quantify how xanthan improved TCE removal, we spiked the LPZ and surrounding sands with (14)C-lableled TCE and used a multistep flooding procedure that quantified the mass of (14)C-TCE oxidized and bypassed during treatment. Results showed that TCE mass removal was 1.4 times greater in experiments where xanthan was employed. Combining xanthan with MnO4(-) also reduced the mass of TCE in the LPZ that was potentially available for rebound. By coupling a multiple species reactive transport model with the Brinkman equation for non-Newtonian flow, the simulated amount of (14)C-TCE oxidized during transport matched experimental results. These observations support the use of xanthan as a means of enhancing MnO4(-) delivery into LPZs for the treatment of dissolved-phase TCE.

ASU nitrogen sweep gas in hydrogen separation membrane for production of HRSG duct burner fuel

Science.gov (United States)

Panuccio, Gregory J.; Raybold, Troy M.; Jamal, Agil; Drnevich, Raymond Francis

2013-04-02

The present invention relates to the use of low pressure N2 from an air separation unit (ASU) for use as a sweep gas in a hydrogen transport membrane (HTM) to increase syngas H2 recovery and make a near-atmospheric pressure (less than or equal to about 25 psia) fuel for supplemental firing in the heat recovery steam generator (HRSG) duct burner.

Ultrasonic flow-through filtration of microparticles in a microfluidic channel using frequency sweep technique

International Nuclear Information System (INIS)

Seo, Dae Cheol; Ahn, Bong Young; Cho, Seung Hyun; Siddique, A. K. M. Ariful Haque; Kim, Cheol Gi

2013-01-01

Many studies have been conducted on the filtration of microparticles using the acoustic radiation force of ultrasonic standing wave. The present work concerns a flow-through particle filtration method by utilizing frequency varying ultrasound. The periodical frequency sweep of the ultrasonic standing wave translocates particles across a microchannel, where particles in fluid flow are filtrated without barriers. The present filtration technique in a microfluidic channel was proposed conceptually in the 1990s. However, its experimental realization on actual particles in a microfluidic channel has not been carried out in a notable way. Several sizes of polystyrene microspheres (10 µm to 90 µm) and silicon carbide (SiC) particles (37 µm) suspended in water were applied as a test sample. For filtration of those particles, a Y-branched microfluidic channel with one inlet and two outlets was made out of steel and acrylic as a form of modulized device. Ultrasound of a few MHz in band frequency (1.75 MHz to 3.05 MHz) was transmitted into one side of the channel wall to generate a standing wave field in fluid flow. The periodical frequency sweep operation showed successful filtration performance, whereby particles in water flowed into one outlet and purified water flowed into the other outlet of the Y branch of the channel.

Selective sweeps in growing microbial colonies

International Nuclear Information System (INIS)

Korolev, Kirill S; Müller, Melanie J I; Murray, Andrew W; Nelson, David R; Karahan, Nilay; Hallatschek, Oskar

2012-01-01

Evolutionary experiments with microbes are a powerful tool to study mutations and natural selection. These experiments, however, are often limited to the well-mixed environments of a test tube or a chemostat. Since spatial organization can significantly affect evolutionary dynamics, the need is growing for evolutionary experiments in spatially structured environments. The surface of a Petri dish provides such an environment, but a more detailed understanding of microbial growth on Petri dishes is necessary to interpret such experiments. We formulate a simple deterministic reaction–diffusion model, which successfully predicts the spatial patterns created by two competing species during colony expansion. We also derive the shape of these patterns analytically without relying on microscopic details of the model. In particular, we find that the relative fitness of two microbial strains can be estimated from the logarithmic spirals created by selective sweeps. The theory is tested with strains of the budding yeast Saccharomyces cerevisiae for spatial competitions with different initial conditions and for a range of relative fitnesses. The reaction–diffusion model also connects the microscopic parameters like growth rates and diffusion constants with macroscopic spatial patterns and predicts the relationship between fitness in liquid cultures and on Petri dishes, which we confirmed experimentally. Spatial sector patterns therefore provide an alternative fitness assay to the commonly used liquid culture fitness assays. (paper)

Selective sweeps in growing microbial colonies

Science.gov (United States)

Korolev, Kirill S.; Müller, Melanie J. I.; Karahan, Nilay; Murray, Andrew W.; Hallatschek, Oskar; Nelson, David R.

2012-04-01

Evolutionary experiments with microbes are a powerful tool to study mutations and natural selection. These experiments, however, are often limited to the well-mixed environments of a test tube or a chemostat. Since spatial organization can significantly affect evolutionary dynamics, the need is growing for evolutionary experiments in spatially structured environments. The surface of a Petri dish provides such an environment, but a more detailed understanding of microbial growth on Petri dishes is necessary to interpret such experiments. We formulate a simple deterministic reaction-diffusion model, which successfully predicts the spatial patterns created by two competing species during colony expansion. We also derive the shape of these patterns analytically without relying on microscopic details of the model. In particular, we find that the relative fitness of two microbial strains can be estimated from the logarithmic spirals created by selective sweeps. The theory is tested with strains of the budding yeast Saccharomyces cerevisiae for spatial competitions with different initial conditions and for a range of relative fitnesses. The reaction-diffusion model also connects the microscopic parameters like growth rates and diffusion constants with macroscopic spatial patterns and predicts the relationship between fitness in liquid cultures and on Petri dishes, which we confirmed experimentally. Spatial sector patterns therefore provide an alternative fitness assay to the commonly used liquid culture fitness assays.

Quarter-Sweep Iteration Concept on Conjugate Gradient Normal Residual Method via Second Order Quadrature - Finite Difference Schemes for Solving Fredholm Integro-Differential Equations

International Nuclear Information System (INIS)

Aruchunan, E.

2015-01-01

In this paper, we have examined the effectiveness of the quarter-sweep iteration concept on conjugate gradient normal residual (CGNR) iterative method by using composite Simpson's (CS) and finite difference (FD) discretization schemes in solving Fredholm integro-differential equations. For comparison purposes, Gauss- Seidel (GS) and the standard or full- and half-sweep CGNR methods namely FSCGNR and HSCGNR are also presented. To validate the efficacy of the proposed method, several analyses were carried out such as computational complexity and percentage reduction on the proposed and existing methods. (author)

Grain boundary sweeping and dissolution effects on fission product behavior under severe fuel damage accident conditions

International Nuclear Information System (INIS)

Rest, J.

1985-10-01

The theoretical FASTGRASS-VFP model has been used in the interpretation of fission gas, iodine, tellurium, and cesium release from severe-fuel-damage (SFD) tests performed in the PBF reactor in Idaho. A theory of grain boundary sweeping of gas bubbles, gas bubble behavior during fuel liquefaction (destruction of grain boundaries due to formation of a U-rich melt phase), and during U-Zr eutectic melting has been included within the FASTGRASS-VFP formalism. The grain-boundary-sweeping theory considers the interaction between the moving grain boundary and two distinct size classes of bubbles, those on grain faces and on grain edges. The theory of the effects of fuel liquefaction and U-Zr eutectic melting on fission product behavior considers the migration and coalescence of fission gas bubbles in either molten uranium, or a zircaloy-uranium eutectic melt. The FASTGRASS-VFP predictions, measured release rates from the above tests, and previously published release rates are compared and differences between fission product behavior in trace-irradiated and in normally irradiated fuel are highlighted

A state-and-transition simulation modeling approach for estimating the historical range of variability

Directory of Open Access Journals (Sweden)

Kori Blankenship

2015-04-01

Full Text Available Reference ecological conditions offer important context for land managers as they assess the condition of their landscapes and provide benchmarks for desired future conditions. State-and-transition simulation models (STSMs are commonly used to estimate reference conditions that can be used to evaluate current ecosystem conditions and to guide land management decisions and activities. The LANDFIRE program created more than 1,000 STSMs and used them to assess departure from a mean reference value for ecosystems in the United States. While the mean provides a useful benchmark, land managers and researchers are often interested in the range of variability around the mean. This range, frequently referred to as the historical range of variability (HRV, offers model users improved understanding of ecosystem function, more information with which to evaluate ecosystem change and potentially greater flexibility in management options. We developed a method for using LANDFIRE STSMs to estimate the HRV around the mean reference condition for each model state in ecosystems by varying the fire probabilities. The approach is flexible and can be adapted for use in a variety of ecosystems. HRV analysis can be combined with other information to help guide complex land management decisions.

An angularly refineable phase space finite element method with approximate sweeping procedure

International Nuclear Information System (INIS)

Kophazi, J.; Lathouwers, D.

2013-01-01

An angularly refineable phase space finite element method is proposed to solve the neutron transport equation. The method combines the advantages of two recently published schemes. The angular domain is discretized into small patches and patch-wise discontinuous angular basis functions are restricted to these patches, i.e. there is no overlap between basis functions corresponding to different patches. This approach yields block diagonal Jacobians with small block size and retains the possibility for S n -like approximate sweeping of the spatially discontinuous elements in order to provide efficient preconditioners for the solution procedure. On the other hand, the preservation of the full FEM framework (as opposed to collocation into a high-order S n scheme) retains the possibility of the Galerkin interpolated connection between phase space elements at arbitrary levels of discretization. Since the basis vectors are not orthonormal, a generalization of the Riemann procedure is introduced to separate the incoming and outgoing contributions in case of unstructured meshes. However, due to the properties of the angular discretization, the Riemann procedure can be avoided at a large fraction of the faces and this fraction rapidly increases as the level of refinement increases, contributing to the computational efficiency. In this paper the properties of the discretization scheme are studied with uniform refinement using an iterative solver based on the S 2 sweep order of the spatial elements. The fourth order convergence of the scalar flux is shown as anticipated from earlier schemes and the rapidly decreasing fraction of required Riemann faces is illustrated. (authors)

The Variable Transition State in Polar Additions to Pi Bonds

Science.gov (United States)

Weiss, Hilton M.

2010-01-01

A vast majority of polar additions of Bronsted acids to alkynes involve a termolecular transition state. With strong acids, considerable positive charge is developed on carbon and Markovnikov addition predominates. In less acidic solutions, however, the reaction is much slower and the transition state more closely resembles the olefinic product.…

Improved capacitance sensor with variable operating frequency for scanning capacitance microscopy

International Nuclear Information System (INIS)

Kwon, Joonhyung; Kim, Joonhui; Jeong, Jong-Hwa; Lee, Euy-Kyu; Seok Kim, Yong; Kang, Chi Jung; Park, Sang-il

2005-01-01

Scanning capacitance microscopy (SCM) has been gaining attention for its capability to measure local electrical properties in doping profile, oxide thickness, trapped charges and charge dynamics. In many cases, stray capacitance produced by different samples and measurement conditions affects the resonance frequency of a capacitance sensor. The applications of conventional SCM are critically limited by the fixed operating frequency and lack of tunability in its SCM sensor. In order to widen SCM application to various samples, we have developed a novel SCM sensor with variable operating frequency. By performing variable frequency sweep over the band of 160 MHz, the SCM sensor is tuned to select the best and optimized resonance frequency and quality factor for each sample measurement. The fundamental advantage of the new variable frequency SCM sensor was demonstrated in the SCM imaging of silicon oxide nano-crystals. Typical sensitivity of the variable frequency SCM sensor was found to be 10 -19 F/V

TRANSITING THE SUN. II. THE IMPACT OF STELLAR ACTIVITY ON Lyα TRANSITS

Energy Technology Data Exchange (ETDEWEB)

Llama, J.; Shkolnik, E. L., E-mail: joe.llama@lowell.edu [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

2016-01-20

High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure the properties of transiting exoplanets in the presence of stellar activity. Here we insert the transit of a hot Jupiter into continuous disk integrated data of the Sun in Lyα from NASA’s Solar Dynamics Observatory/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio (R{sub p}/R{sub ⋆}). In 75% of our simulated light curves, we measure the correct radius ratio; however, incorrect values can be measured if there is significant short-term variability in the light curve. The maximum measured value of R{sub p}/R{sub ⋆} is 50% larger than the input value, which is much smaller than the large Lyα transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations without a transit and found that stellar activity cannot mimic the Lyα transit of 55 Cancari b, strengthening the conclusion that this planet has a partially transiting exopshere. We were able to compare our simulations to more active stars by artificially increasing the variability in the Solar Lyα light curve. In the higher variability data, the largest value of R{sub p}/R{sub ⋆} we measured is <3× the input value, which again is not large enough to reproduce the Lyα transit depth reported for the more active stars HD 189733 and GJ 436, supporting the interpretation that these planets have extended atmospheres and possible cometary tails.

Dynamic control of low-Z material deposition and tungsten erosion by strike point sweeping on DIII-D

Directory of Open Access Journals (Sweden)

J. Guterl

2017-08-01

Full Text Available Carbon deposition on tungsten between ELMs was investigated in DIII-D in semi-attached/detached H-mode plasma conditions using fixed outer strike point (OSP positions. Carbon deposition during plasma exposure of tungsten was monitored in-situ by measuring the reflectivity of the tungsten sample surface. No significant carbon deposition, i.e., without strong variations of the reflectivity, was observed during these experiments including discharges at high densities. In contrast, ERO modeling predicts a significant carbon deposition on the tungsten surface for those high density plasma conditions. The surface reflectivity decreases with methane injection, consistent with increased carbon coverage, as expected. The sweeping of OSP leads to a pronounced increase of the surface reflectivity, suggesting that the strike point sweeping may provide an effective means to remove carbon coating from tungsten surface. The ERO modeling however predicts again a regime of carbon deposition for these experiments. The discrepancies between carbon deposition regime predicted by the ERO model and the experimental observations suggest that carbon erosion during ELMs may significantly affect carbon deposition on tungsten.

A parallel sweeping preconditioner for frequency-domain seismic wave propagation

KAUST Repository

Poulson, Jack

2012-09-01

We present a parallel implementation of Engquist and Ying\\'s sweeping preconditioner, which exploits radiation boundary conditions in order to form an approximate block LDLT factorization of the Helmholtz operator with only O(N4/3) work and an application (and memory) cost of only O(N logN). The approximate factorization is then used as a preconditioner for GMRES, and we show that essentially O(1) iterations are required for convergence, even for the full SEG/EAGE over-thrust model at 30 Hz. In particular, we demonstrate the solution of said problem in a mere 15 minutes on 8192 cores of TACC\\'s Lonestar, which may be the largest-scale 3D heterogeneous Helmholtz calculation to date. Generalizations of our parallel strategy are also briefly discussed for time-harmonic linear elasticity and Maxwell\\'s equations.

PH Sensitive Polymers for Improving Reservoir Sweep and Conformance Control in Chemical Flooring

Energy Technology Data Exchange (ETDEWEB)

Mukul Sharma; Steven Bryant; Chun Huh

2008-03-31

There is an increasing opportunity to recover bypassed oil from depleted, mature oilfields in the US. The recovery factor in many reservoirs is low due to inefficient displacement of the oil by injected fluids (typically water). The use of chemical flooding methods to increase recovery efficiencies is severely constrained by the inability of the injected chemicals to contact the bypassed oil. Low sweep efficiencies are the primary cause of low oil recoveries observed in the field in chemical flooding operations even when lab studies indicate high oil recovery efficiency. Any technology that increases the ability of chemical flooding agents to better contact the remaining oil and reduce the amount of water produced in conjunction with the produced oil will have a significant impact on the cost of producing oil domestically in the US. This translates directly into additional economically recoverable reserves, which extends the economic lives of marginal and mature wells. The objective of this research project was to develop a low-cost, pH-triggered polymer for use in IOR processes to improve reservoir sweep efficiency and reservoir conformance in chemical flooding. Rheological measurements made on the polymer solution, clearly show that it has a low viscosity at low pH and exhibits a sudden increase in viscosity (by 2 orders of magnitude or more) at a pH of 3.5 to 4. This implies that the polymer would preferentially flow into zones containing water since the effective permeability to water is highest in these zones. As the pH of the zone increases due to the buffering capacity of the reservoir rock, the polymer solution undergoes a liquid to gel transition causing a sharp increase in the viscosity of the polymer solution in these zones. This allows operationally robust, in-depth conformance treatment of such water bearing zones and better mobility control. The rheological properties of HPAM solutions were measured. These include: steady-shear viscosity and

Study of plasma turbulence by ultrafast sweeping reflectometry on the Tore Supra Tokamak

International Nuclear Information System (INIS)

Hornung, Gregoire

2013-01-01

The performance of a fusion reactor is closely related to the turbulence present in the plasma. The latter is responsible for anomalous transport of heat and particles that degrades the confinement. The measure and characterization of turbulence in tokamak plasma is therefore essential to the understanding and control of this phenomenon. Among the available diagnostics, the sweeping reflectometer installed on Tore Supra allows to access the plasma density fluctuations from the edge to the centre of the plasma discharge with a fine spatial (mm) and temporal resolution (μs), that is of the order of the characteristic turbulence scales.This thesis consisted in the characterization of plasma turbulence in Tore Supra by ultrafast sweeping reflectometry measurements. Correlation analyses are used to quantify the spatial and temporal scales of turbulence as well as their radial velocity. In the first part, the characterization of turbulence properties from the reconstructed plasma density profiles is discussed, in particular through a comparative study with Langmuir probe data. Then, a parametric study is presented, highlighting the effect of collisionality on turbulence, an interpretation of which is proposed in terms of the stabilization of trapped electron turbulence in the confined plasma. Finally, it is shown how additional heating at ion cyclotron frequency produces a significant though local modification of the turbulence in the plasma near the walls, resulting in a strong increase of the structure velocity and a decrease of the correlation time. The supposed effect of rectified potentials generated by the antenna is investigated via numerical simulations. (author) [fr

Implications of climate variability for the detection of multiple equilibria and for rapid transitions in the atmosphere-vegetation system

Energy Technology Data Exchange (ETDEWEB)

Bathiany, S. [Max Planck Institute for Meteorology, Hamburg (Germany); Claussen, M. [Max Planck Institute for Meteorology, Hamburg (Germany); Universitaet Hamburg, Meteorologisches Institut, Hamburg (Germany); Fraedrich, K. [Universitaet Hamburg, Meteorologisches Institut, Hamburg (Germany)

2012-05-15

Paleoclimatic records indicate a decline of vegetation cover in the Western Sahara at the end of the African Humid Period (about 5,500 years before present). Modelling studies have shown that this phenomenon may be interpreted as a critical transition that results from a bifurcation in the atmosphere-vegetation system. However, the stability properties of this system are closely linked to climate variability and depend on the climate model and the methods of analysis. By coupling the Planet Simulator (PlaSim), an atmosphere model of intermediate complexity, with the simple dynamic vegetation model VECODE, we assess previous methods for the detection of multiple equilibria, and demonstrate their limitations. In particular, a stability diagram can yield misleading results because of spatial interactions, and the system's steady state and its dependency on initial conditions are affected by atmospheric variability and nonlinearities. In addition, we analyse the implications of climate variability for the abruptness of a vegetation decline. We find that a vegetation collapse can happen at different locations at different times. These collapses are possible despite large and uncorrelated climate variability. Because of the nonlinear relation between vegetation dynamics and precipitation the green state is initially stabilised by the high variability. When precipitation falls below a critical threshold, the desert state is stabilised as variability is then also decreased. (orig.)

Calculating qP-wave traveltimes in 2-D TTI media by high-order fast sweeping methods with a numerical quartic equation solver

Science.gov (United States)

Han, Song; Zhang, Wei; Zhang, Jie

2017-09-01

A fast sweeping method (FSM) determines the first arrival traveltimes of seismic waves by sweeping the velocity model in different directions meanwhile applying a local solver. It is an efficient way to numerically solve Hamilton-Jacobi equations for traveltime calculations. In this study, we develop an improved FSM to calculate the first arrival traveltimes of quasi-P (qP) waves in 2-D tilted transversely isotropic (TTI) media. A local solver utilizes the coupled slowness surface of qP and quasi-SV (qSV) waves to form a quartic equation, and solve it numerically to obtain possible traveltimes of qP-wave. The proposed quartic solver utilizes Fermat's principle to limit the range of the possible solution, then uses the bisection procedure to efficiently determine the real roots. With causality enforced during sweepings, our FSM converges fast in a few iterations, and the exact number depending on the complexity of the velocity model. To improve the accuracy, we employ high-order finite difference schemes and derive the second-order formulae. There is no weak anisotropy assumption, and no approximation is made to the complex slowness surface of qP-wave. In comparison to the traveltimes calculated by a horizontal slowness shooting method, the validity and accuracy of our FSM is demonstrated.

Connecting the failure of K-theory inside and above vegetation canopies and ejection-sweep cycles by a large eddy simulation

International Nuclear Information System (INIS)

Banerjee, Tirtha; De Roo, Frederik; Mauder, Matthias

2017-01-01

Parameterizations of biosphere-atmosphere interaction processes in climate models and other hydrological applications require characterization of turbulent transport of momentum and scalars between vegetation canopies and the atmosphere, which is often modeled using a turbulent analogy to molecular diffusion processes. However, simple flux-gradient approaches (K-theory) fail for canopy turbulence. One cause is turbulent transport by large coherent eddies at the canopy scale, which can be linked to sweep-ejection events, and bear signatures of non-local organized eddy motions. K-theory, that parameterizes the turbulent flux or stress proportional to the local concentration or velocity gradient, fails to account for these non-local organized motions. The connection to sweep-ejection cycles and the local turbulent flux can be traced back to the turbulence triple moment (C ′ W ′ W ′ )-bar. In this work, we use large-eddy simulation to investigate the diagnostic connection between the failure of K-theory and sweep-ejection motions. Analyzed schemes are quadrant analysis (QA) and a complete and incomplete cumulant expansion (CEM and ICEM) method. The latter approaches introduce a turbulence timescale in the modeling. Furthermore, we find that the momentum flux needs a different formulation for the turbulence timescale than the sensible heat flux. In conclusion, accounting for buoyancy in stratified conditions is also deemed to be important in addition to accounting for non-local events to predict the correct momentum or scalar fluxes.

Electric-Field Control of Oxygen Vacancies and Magnetic Phase Transition in a Cobaltite/Manganite Bilayer

Science.gov (United States)

Cui, B.; Song, C.; Li, F.; Zhong, X. Y.; Wang, Z. C.; Werner, P.; Gu, Y. D.; Wu, H. Q.; Saleem, M. S.; Parkin, S. S. P.; Pan, F.

2017-10-01

Manipulation of oxygen vacancies (VO ) in single oxide layers by varying the electric field can result in significant modulation of the ground state. However, in many oxide multilayers with strong application potentials, e.g., ferroelectric tunnel junctions and solid-oxide fuel cells, understanding VO behavior in various layers under an applied electric field remains a challenge, owing to complex VO transport between different layers. By sweeping the external voltage, a reversible manipulation of VO and a corresponding fixed magnetic phase transition sequence in cobaltite/manganite (SrCoO3 -x/La0.45Sr0.55MnO3 -y ) heterostructures are reported. The magnetic phase transition sequence confirms that the priority of electric-field-induced VO formation or annihilation in the complex bilayer system is mainly determined by the VO formation energies and Gibbs free-energy differences, which is supported by theoretical analysis. We not only realize a reversible manipulation of the magnetic phase transition in an oxide bilayer but also provide insight into the electric-field control of VO engineering in heterostructures.

Effect of current compliance and voltage sweep rate on the resistive switching of HfO2/ITO/Invar structure as measured by conductive atomic force microscopy

International Nuclear Information System (INIS)

Wu, You-Lin; Liao, Chun-Wei; Ling, Jing-Jenn

2014-01-01

The electrical characterization of HfO 2 /ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO 2 surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO 2 /ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

Ion source plasma parameters measurement based on Langmuir probe with commercial frequency sweep

International Nuclear Information System (INIS)

Xie, Y.H.; Hu, C.D.; Liu, S.; Shong, S.H.; Jiang, C.C.; Liu, Z.M.

2010-01-01

Langmuir probe is one of the main diagnostic tools to measure the plasma parameters in the ion source. In this article, the commercial frequency power, which is sine wave of 50 Hz, was supplied on the Langmuir probe to measure the plasma parameters. The best feature of this probe sweep voltage is that it does not need extra design. The probe I-V characteristic curve can be got in less than 5 ms and the plasma parameters, the electron temperature and the electron density, varying with the time can be got in one plasma discharge of 400 ms.

The strong selective sweep candidate gene ADRA2C does not explain domestication related changes in the stress response of chickens.

Directory of Open Access Journals (Sweden)

Magnus Elfwing

Full Text Available Analysis of selective sweeps to pinpoint causative genomic regions involved in chicken domestication has revealed a strong selective sweep on chromosome 4 in layer chickens. The autoregulatory α-adrenergic receptor 2C (ADRA2C gene is the closest to the selective sweep and was proposed as an important gene in the domestication of layer chickens. The ADRA2C promoter region was also hypermethylated in comparison to the non-selected ancestor of all domesticated chicken breeds, the Red Junglefowl, further supporting its relevance. In mice the receptor is involved in the fight-or-flight response as it modulates epinephrine release from the adrenals. To investigate the involvement of ADRA2C in chicken domestication, we measured gene expression in the adrenals and radiolabeled receptor ligand in three brain regions comparing the domestic White Leghorn strain with the wild ancestor Red Junglefowl. In adrenals ADRA2C was twofold greater expressed than the related receptor gene ADRA2A, indicating that ADRA2C is the predominant modulator of epinephrine release but no strain differences were measured. In hypothalamus and amygdala, regions associated with the stress response, and in striatum, receptor binding pIC50 values ranged between 8.1-8.4, and the level was not influenced by the genotyped allele. Because chicken strains differ in morphology, physiology and behavior, differences attributed to a single gene may be lost in the noise caused by the heterogeneous genetic background. Therefore an F10 advanced intercross strain between White Leghorn and Red Junglefowl was used to investigate effects of ADRA2C alleles on fear related behaviors and fecundity. We did not find compelling genotype effects in open field, tonic immobility, aerial predator, associative learning or fecundity. Therefore we conclude that ADRA2C is probably not involved in the domestication of the stress response in chicken, and the strong selective sweep is probably caused by selection

Femtosecond Laser Tagging Characterization of a Sweeping Jet Actuator Operating in the Compressible Regime

Science.gov (United States)

Peters, Christopher J.; Miles, Richard B.; Burns, Ross A.; Bathel, Brett F.; Jones, Gregory S.; Danehy, Paul M.

2016-01-01

A sweeping jet (SWJ) actuator operating over a range of nozzle pressure ratios (NPRs) was characterized with femtosecond laser electronic excitation tagging (FLEET), single hot-wire anemometry (HWA) and high-speed/phase-averaged schlieren. FLEET velocimetry was successfully demonstrated in a highly unsteady, oscillatory flow containing subsonic through supersonic velocities. Qualitative comparisons between FLEET and HWA (which measured mass flux since the flow was compressible) showed relatively good agreement in the external flow profiles. The spreading rate was found to vary from 0.5 to 1.2 depending on the pressure ratio. The precision of FLEET velocity measurements in the external flow field was poorer (is approximately equal to 25 m/s) than reported in a previous study due to the use of relatively low laser fluences, impacting the velocity fluctuation measurements. FLEET enabled velocity measurements inside the device and showed that choking likely occurred for NPR = 2.0, and no internal shockwaves were present. Qualitative oxygen concentration measurements using FLEET were explored in an effort to gauge the jet's mixing with the ambient. The jet was shown to mix well within roughly four throat diameters and mix fully within roughly eight throat diameters. Schlieren provided visualization of the internal and external flow fields and showed that the qualitative structure of the internal flow does not vary with pressure ratio and the sweeping mechanism observed for incompressible NPRs also probably holds for compressible NPRs.

Grain boundary sweeping and liquefaction-induced fission product behavior in nuclear fuel under severe-core damage accident conditions

International Nuclear Information System (INIS)

Rest, J.

1984-05-01

The theoretical FASTGRASS-VFP model has been used in the interpretation of fission gas, iodine, tellurium, and cesium release from: (1) irradiated high-burnup LWR fuel in a flowing steam atmosphere during high-temperature, in-cell heating tests performed at Oak Ridge National Laboratory; and (2) trace-irradiated and high-burnup LWR fuel during severe-fuel-damage (SFD) tests performed in the PBF reactor in Idaho. A theory of grain boundary sweeping of gas bubbles, gas bubble behavior during fuel liquefaction (destruction of grain boundaries due to formation of a U-rich melt phase), and U-Zr eutectic melting has been included within the FASTGRASS-VFP formalism. Results of the analyses demonstrate that intragranular fission product behavior during both types of tests can be interpreted in terms of a grain-growth/grain-boundary-sweeping mechanism that enhances the flow of fission products from within the grains to the grain boundaries. Whereas fuel liquefaction leads to an enhanced release of fission products in trace-irradiated fuel, the occurrence of fuel liquefaction in high-burnup fuel can degrade fission product release. This phenomenon is due in part to reduced gas-bubble mobilities in a viscous medium as compared to vapor transport, and in part to a degradation of grain growth rates and the subsequent decrease in grain-boundary sweeping of intragranular fission products into the liquefied lamina. The analysis shows that total UO 2 dissolution due to eutectic melting leads to increased release for both trace-irradiated and high-burnup fuel. The FASTGRASS-VFP predictions, measured release rates from the above tests, and previously published release rates are compared and differences between fission product behavior in trace-irradiated and in high-burnup fuel are highlighted

Effects of Atlantic warm pool variability over climate of South America tropical transition zone

Science.gov (United States)

Ricaurte Villota, Constanza; Romero-Rodríguez, Deisy; Andrés Ordoñez-Zuñiga, Silvio; Murcia-Riaño, Magnolia; Coca-Domínguez, Oswaldo

2016-04-01

Colombia is located in the northwestern corner of South America in a climatically complex region due to the influence processes modulators of climate both the Pacific and Atlantic region, becoming in a transition zone between phenomena of northern and southern hemisphere. Variations in the climatic conditions of this region, especially rainfall, have been attributed to the influence of the El Nino Southern Oscillation (ENSO), but little is known about the interaction within Atlantic Ocean and specifically Caribbean Sea with the environmental conditions of this region. In this work We studied the influence of the Atlantic Warm Pool (AWP) on the Colombian Caribbean (CC) climate using data of Sea Surface Temperature (SST) between 1900 - 2014 from ERSST V4, compared with in situ data SIMAC (National System for Coral Reef Monitoring in Colombia - INVEMAR), rainfall between 1953-2013 of meteorological stations located at main airports in the Colombian Caribbean zone, administered by IDEAM, and winds data between 2003 - 2014 from WindSat sensor. The parameters analyzed showed spatial differences throughout the study area. SST anomalies, representing the variability of the AWP, showed to be associated with Multidecadal Atlantic Oscillation (AMO) and with the index of sea surface temperature of the North-tropical Atlantic (NTA), the variations was on 3 to 5 years on the ENSO scale and of approximately 11 years possibly related to solar cycles. Rainfall anomalies in the central and northern CC respond to changes in SST, while in the south zone these are not fully engage and show a high relationship with the ENSO. Finally, the winds also respond to changes in SST and showed a signal approximately 90 days possibly related to the Madden-Julian Oscillation, whose intensity depends on the CC region being analyzed. The results confirm that region is a transition zone in which operate several forcing, the variability of climate conditions is difficult to attribute only one, as ENSO

Determination of underivatized amino acids to evaluate quality of beer by capillary electrophoresis with online sweeping technique.

Science.gov (United States)

Luo, Tian; Ke, Jing; Xie, Yunfei; Dong, Yuming

2017-10-01

Capillary electrophoresis (CE) with ultraviolet detection was applied to determine underivatized amino acids in beer, based on the coordination interaction of copper ions and amino acids. An online sweeping technique was combined with CE to improve detection sensitivity. Using the United Nations Food Agriculture Organization/World Health Organization model of essential amino acid pattern and flavor of amino acids, the quality and taste in three kinds of beer were evaluated. It was found that Beer2 had higher quality than the other two kinds and the content of phenylalanine, proline, serine, and isoleucine was relatively large in all three kinds of beers with a great influence on beer flavor. Optimal conditions for separation were as follows: 50mM CuSO 4 at pH 4.40 as buffer; total length of fused silica capillary, 73 cm; effective length, 65 cm; separation voltage, 22.5 kV; and optimized sweeping condition, 70 seconds. In the appropriate range, linearity (r 2  > 0.9989), precision with a relative standard deviation amino acids in beer and to perform quantitative analysis directly without derivatization for the first time. Copyright © 2017. Published by Elsevier B.V.

Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition

International Nuclear Information System (INIS)

Fernández-Pacheco, A.; Mansell, R.; Petit, D.; Lee, J. H.; Cowburn, R. P.; Ummelen, F. C.; Swagten, H. J. M.

2014-01-01

We have designed a bilayer synthetic antiferromagnet where the order of layer reversal can be selected by varying the sweep rate of the applied magnetic field. The system is formed by two ultra-thin ferromagnetic layers with different proximities to the spin reorientation transition, coupled antiferromagnetically using Ruderman-Kittel-Kasuya-Yosida interactions. The different dynamic magnetic reversal behavior of both layers produces a crossover in their switching fields for field rates in the kOe/s range. This effect is due to the different effective anisotropy of both layers, added to an appropriate asymmetric antiferromagnetic coupling between them. Field-rate controlled selective switching of perpendicular magnetic anisotropy layers as shown here can be exploited in sensing and memory applications.

Superconducting fault current-limiter with variable shunt impedance

Science.gov (United States)

Llambes, Juan Carlos H; Xiong, Xuming

2013-11-19

A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

A selective sweep in a Varroa destructor resistant honeybee (Apis mellifera) population.

Science.gov (United States)

Lattorff, H Michael G; Buchholz, Josephine; Fries, Ingemar; Moritz, Robin F A

2015-04-01

The mite Varroa destructor is one of the most dangerous parasites of the Western honeybee (Apis mellifera) causing enormous colony losses worldwide. Various chemical treatments for the control of the Varroa mite are currently in use, which, however, lead to residues in bee products and often to resistance in mites. This facilitated the exploration of alternative treatment methods and breeding for mite resistant honeybees has been in focus for breeders in many parts of the world with variable results. Another approach has been applied to a honeybee population on Gotland (Sweden) that was exposed to natural selection and survived Varroa-infestation for more than 10years without treatment. Eventually this population became resistant to the parasite by suppressing the reproduction of the mite. A previous QTL mapping study had identified a region on chromosome 7 with major loci contributing to the mite resistance. Here, a microsatellite scan of the significant candidate QTL regions was used to investigate potential footprints of selection in the original population by comparing the study population on Gotland before (2000) and after selection (2007). Genetic drift had caused an extreme loss of genetic diversity in the 2007 population for all genetic markers tested. In addition to this overall reduction of heterozygosity, two loci on chromosome 7 showed an even stronger and significant reduction in diversity than expected from genetic drift alone. Within the selective sweep eleven genes are annotated, one of them being a putative candidate to interfere with reduced mite reproduction. A glucose-methanol-choline oxidoreductase (GMCOX18) might be involved in changing volatiles emitted by bee larvae that might be essential to trigger oogenesis in Varroa. Copyright © 2015 Elsevier B.V. All rights reserved.

Spatial and temporal variability of interhemispheric transport times

Science.gov (United States)

Wu, Xiaokang; Yang, Huang; Waugh, Darryn W.; Orbe, Clara; Tilmes, Simone; Lamarque, Jean-Francois

2018-05-01

The seasonal and interannual variability of transport times from the northern midlatitude surface into the Southern Hemisphere is examined using simulations of three idealized age tracers: an ideal age tracer that yields the mean transit time from northern midlatitudes and two tracers with uniform 50- and 5-day decay. For all tracers the largest seasonal and interannual variability occurs near the surface within the tropics and is generally closely coupled to movement of the Intertropical Convergence Zone (ITCZ). There are, however, notable differences in variability between the different tracers. The largest seasonal and interannual variability in the mean age is generally confined to latitudes spanning the ITCZ, with very weak variability in the southern extratropics. In contrast, for tracers subject to spatially uniform exponential loss the peak variability tends to be south of the ITCZ, and there is a smaller contrast between tropical and extratropical variability. These differences in variability occur because the distribution of transit times from northern midlatitudes is very broad and tracers with more rapid loss are more sensitive to changes in fast transit times than the mean age tracer. These simulations suggest that the seasonal-interannual variability in the southern extratropics of trace gases with predominantly NH midlatitude sources may differ depending on the gases' chemical lifetimes.

Detection of undistorted continuous wave (CW) electron paramagnetic resonance (EPR) spectra with non-adiabatic rapid sweep (NARS) of the magnetic field

Science.gov (United States)

Kittell, Aaron W.; Camenisch, Theodore G.; Ratke, Joseph J.; Sidabras, Jason W.; Hyde, James S.

2011-01-01

A continuous wave (CW) electron paramagnetic resonance (EPR) spectrum is typically displayed as the first harmonic response to the application of 100 kHz magnetic field modulation, which is used to enhance sensitivity by reducing the level of 1/f noise. However, magnetic field modulation of any amplitude causes spectral broadening and sacrifices EPR spectral intensity by at least a factor of two. In the work presented here, a CW rapid-scan spectroscopic technique that avoids these compromises and also provides a means of avoiding 1/f noise is developed. This technique, termed non-adiabatic rapid sweep (NARS) EPR, consists of repetitively sweeping the polarizing magnetic field in a linear manner over a spectral fragment with a small coil at a repetition rate that is sufficiently high that receiver noise, microwave phase noise, and environmental microphonics, each of which has 1/f characteristics, are overcome. Nevertheless, the rate of sweep is sufficiently slow that adiabatic responses are avoided and the spin system is always close to thermal equilibrium. The repetitively acquired spectra from the spectral fragment are averaged. Under these conditions, undistorted pure absorption spectra are obtained without broadening or loss of signal intensity. A digital filter such as a moving average is applied to remove high frequency noise, which is approximately equivalent in bandwidth to use of an integrating time constant in conventional field modulation with lock-in detection. Nitroxide spectra at L- and X-band are presented. PMID:21741868

Surfaces Relief Profilometry of Solid Objects by Sweeping of a Laser Line

Science.gov (United States)

Salas-Peimbert, Didia P.; Trujillo-Schiaffino, Gerardo; Mendoza-Villegas, Paloma G.; Ojeda-González, Daniel; Almazán-Cuellar, Saúl; Corral-Martínez, Luis F.

2008-04-01

This paper describes the development of a laser system for the digitalization and three-dimensional reconstruction of solid objects. The first step consists of applying on the object a linear sweeping of a thin laser line using a laser diode with 635 nm and 5 mW, a motorized stage for linear displacement of 138 mm, and a controller with RS232 interface. The next step consists of capturing and transmitting the image of the deformed line on the object to a computer. For this step was used a monochrome camera CCD, and an image acquisition board. The last step consists of the three-dimensional reconstruction of the solid object. All the corresponding algorithms were implemented using the programming language LabVIEW.

EQUATIONS OF RADIATION TRANSFER IN INFRARED TOMOGRAPHY IN THE CASE OF ACTIVE-PASSIVE DIAGNOSIS AND SWEEPING SCANNING

Directory of Open Access Journals (Sweden)

A. A. Makarova

2014-01-01

Full Text Available Sweeping scanning scheme of a hot gas in the task of infrared tomography is formulated. Two diagnosis regimes are used: the active one (ON – with included source and the passive one (OFF – without it. Two integral equations are deduced concerning the absorption coefficient k and the Planck function B of a medium (by which it is possible to calculate the temperature profile of a medium T.

Electric power is not the same power. Why the energy transition can not succeed

International Nuclear Information System (INIS)

Limburg, Michael; Mueller, Fred F.

2015-01-01

The energy transition - the conversion of our power supply to so-called ''Renewable Energy'' - will lead to disaster, economically as well as technically. Although the concept is not technically feasible, more than 500 billion Euros were spent for this purpose already. This money our economy will miss bitterly when it is needed it to go, sweep up the future shambles. Here explain two recognized experts why. ''The book, 'electric power is not the same power' pulled himself together again on a colossal effort. It dissects technically brilliant with the tools of logic, scientific reasoning a fatal mental aberration.''- Arnold Vaatz MP. [de

First measurements of electron-beam transit times and micropulse elongation in a photoelectric injector at the High-Brightness Accelerator FEL (HIBAF)

Energy Technology Data Exchange (ETDEWEB)

Lumpkin, A.H.; Carlsten, B.E.; Feldman, R.B.

1990-01-01

Key aspects of the dynamics of a photoelectric injector (PEI) on the Los Alamos High-Brightness Accelerator FEL (HIBAF) facility have been investigated using a synchroscan streak camera. By phase-locking the streak camera sweep to the reference 108.3 MHz rf signal, the variations of micropulse temporal elongations (30 to 80% over the drive-laser pulse length) and of transit times (25 ps for a 16{degree}-phase change) were observed for the first time. These results were in good agreement with PARMELA simulations. 2 refs., 8 figs.

Generation of constant-amplitude radio-frequency sweeps at a tunnel junction for spin resonance STM

International Nuclear Information System (INIS)

Paul, William; Lutz, Christopher P.; Heinrich, Andreas J.; Baumann, Susanne

2016-01-01

We describe the measurement and successful compensation of the radio-frequency transfer function of a scanning tunneling microscope over a wide frequency range (15.5–35.5 GHz) and with high dynamic range (>50 dB). The precise compensation of cabling resonances and attenuations is critical for the production of constant-voltage frequency sweeps for electric-field driven electron spin resonance (ESR) experiments. We also demonstrate that a well-calibrated tunnel junction voltage is necessary to avoid spurious ESR peaks that can arise due to a non-flat transfer function.

Generation of constant-amplitude radio-frequency sweeps at a tunnel junction for spin resonance STM

Energy Technology Data Exchange (ETDEWEB)

Paul, William; Lutz, Christopher P.; Heinrich, Andreas J. [IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Baumann, Susanne [IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

2016-07-15

We describe the measurement and successful compensation of the radio-frequency transfer function of a scanning tunneling microscope over a wide frequency range (15.5–35.5 GHz) and with high dynamic range (>50 dB). The precise compensation of cabling resonances and attenuations is critical for the production of constant-voltage frequency sweeps for electric-field driven electron spin resonance (ESR) experiments. We also demonstrate that a well-calibrated tunnel junction voltage is necessary to avoid spurious ESR peaks that can arise due to a non-flat transfer function.

Unsteady Flow Simulation of a Sweeping Jet Actuator Using a Lattice-Boltzmann Method

Science.gov (United States)

Duda, B.; Wessels, M.; Fares, E.; Vatsa, V.

2016-01-01

Active flow control technology is increasingly used in aerospace applications to control flow separation and to improve aerodynamic performance. In this paper, PowerFLOW is used to simulate the flow through a sweeping jet actuator at two different pressure ratios. The lower pressure ratio leads to a high subsonic flow, whereas the high pressure ratio produces a choked flow condition. Comparison of numerical results with experimental data is shown, which includes qualitatively good agreement of pressure histories and spectra. PIV measurements are also available but the simulation overestimates mean and fluctuation quantities outside the actuator. If supply pressure is matched at one point inside the mixing chamber a good qualitative agreement is achieved at all other monitor points.

Military Veterans' Midlife Career Transition and Life Satisfaction

Science.gov (United States)

Robertson, Heather C.; Brott, Pamelia E.

2014-01-01

Many military veterans face the challenging transition to civilian employment. Military veteran members of a national program, Troops to Teachers, were surveyed regarding life satisfaction and related internal/external career transition variables. Participants included military veterans who were currently or had previously transitioned to K-12…

Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole-cell oscillations in smooth muscle cells

DEFF Research Database (Denmark)

Jacobsen, Jens Christian; Aalkjær, Christian; Nilsson, Holger

2007-01-01

waves sweeping through the cytoplasm when the SR is stimulated to release calcium. A rise in cyclic guanosine monophosphate (cGMP) leads to the experimentally observed transition from waves to whole-cell calcium oscillations. At the same time membrane potential starts to oscillate and the frequency...... approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes uniform opening of L-type calcium...... onset of oscillations in membrane potential within the individual cell may underlie sudden intercellular synchronization and the appearance of vasomotion. Key words: Vasomotion, Chloride channel, cGMP, Mathematical model, Calcium waves....

Slow-transit Constipation.

Science.gov (United States)

Bharucha, Adil E.; Philips, Sidney F.

2001-08-01

Idiopathic slow-transit constipation is a clinical syndrome predominantly affecting women, characterized by intractable constipation and delayed colonic transit. This syndrome is attributed to disordered colonic motor function. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but are otherwise indistinguishable from irritable bowel syndrome to patients with colonic inertia or chronic megacolon. The diagnosis is made after excluding colonic obstruction, metabolic disorders (hypothyroidism, hypercalcemia), drug-induced constipation, and pelvic floor dysfunction (as discussed by Wald ). Most patients are treated with one or more pharmacologic agents, including dietary fiber supplementation, saline laxatives (milk of magnesia), osmotic agents (lactulose, sorbitol, and polyethylene glycol 3350), and stimulant laxatives (bisacodyl and glycerol). A subtotal colectomy is effective and occasionally is indicated for patients with medically refractory, severe slow-transit constipation, provided pelvic floor dysfunction has been excluded or treated.

Pemodelan Markov Switching Dengan Time-varying Transition Probability

OpenAIRE

Savitri, Anggita Puri; Warsito, Budi; Rahmawati, Rita

2016-01-01

Exchange rate or currency is an economic variable which reflects country's state of economy. It fluctuates over time because of its ability to switch the condition or regime caused by economic and political factors. The changes in the exchange rate are depreciation and appreciation. Therefore, it could be modeled using Markov Switching with Time-Varying Transition Probability which observe the conditional changes and use information variable. From this model, time-varying transition probabili...

Extraordinary variability and sharp transitions in a maximally frustrated dynamic network

Science.gov (United States)

Liu, Wenjia; Schmittmann, Beate; Zia, R. K. P.

2013-03-01

Most previous studies of complex networks have focused on single, static networks. However, in the real world, networks are dynamic and interconnected. Inspired by the presence of extroverts and introverts in the general population, we investigate a highly simplified model of a social network, involving two types of nodes: one preferring the highest degree possible, and one preferring no connections whatsoever. There are only two control parameters in the model: the number of ``introvert'' and ``extrovert'' nodes, NI and NE. Our key findings are as follows: As a function of NI and NE, the system exhibits a highly unusual transition, displaying extraordinary fluctuations (as in 2nd order transitions) and discontinuous jumps (characteristic of 1st order transitions). Most remarkably, the system can be described by an Ising-like Hamiltonian with long-range multi-spin interactions and some of its properties can be obtained analytically. This is in stark contrast with other dynamic network models which rely almost exclusively on simulations. NSF-DMR-1005417/1244666 and and ICTAS Virginia Tech

Selective sweep on human amylase genes postdates the split with Neanderthals

Science.gov (United States)

Inchley, Charlotte E.; Larbey, Cynthia D. A.; Shwan, Nzar A. A.; Pagani, Luca; Saag, Lauri; Antão, Tiago; Jacobs, Guy; Hudjashov, Georgi; Metspalu, Ene; Mitt, Mario; Eichstaedt, Christina A.; Malyarchuk, Boris; Derenko, Miroslava; Wee, Joseph; Abdullah, Syafiq; Ricaut, François-Xavier; Mormina, Maru; Mägi, Reedik; Villems, Richard; Metspalu, Mait; Jones, Martin K.; Armour, John A. L.; Kivisild, Toomas

2016-01-01

Humans have more copies of amylase genes than other primates. It is still poorly understood, however, when the copy number expansion occurred and whether its spread was enhanced by selection. Here we assess amylase copy numbers in a global sample of 480 high coverage genomes and find that regions flanking the amylase locus show notable depression of genetic diversity both in African and non-African populations. Analysis of genetic variation in these regions supports the model of an early selective sweep in the human lineage after the split of humans from Neanderthals which led to the fixation of multiple copies of AMY1 in place of a single copy. We find evidence of multiple secondary losses of copy number with the highest frequency (52%) of a deletion of AMY2A and associated low copy number of AMY1 in Northeast Siberian populations whose diet has been low in starch content. PMID:27853181

Anti-correlated X-ray and Radio Variability in the Transitional Millisecond Pulsar PSR J1023+0038

Science.gov (United States)

Bogdanov, Slavko; Deller, Adam; Miller-Jones, James; Archibald, Anne; Hessels, Jason W. T.; Jaodand, Amruta; Patruno, Alessandro; Bassa, Cees; D'Angelo, Caroline

2018-01-01

The PSR J1023+0038 binary system hosts a 1.69-ms neutron star and a low-mass, main-sequence-like star. The system underwent a transformation from a rotation-powered to a low-luminosity accreting state in 2013 June, in which it has remained since. We present an unprecedented set of strictly simultaneous Chandra X-ray Observatory and Karl G. Jansky Very Large Array observations, which for the first time reveal a highly reproducible, anti-correlated variability pattern. Rapid declines in X-ray flux are always accompanied by a radio brightening with duration that closely matches the low X-ray flux mode intervals. We discuss these findings in the context of accretion and jet outflow physics and their implications for using the radio/X-ray luminosity plane to distinguish low-luminosity candidate black hole binary systems from accreting transitional millisecond pulsars.

Comparison of Gasoline and Primary Reference Fuel in the Transition from HCCI to PPC

KAUST Repository

Li, Changle

2017-10-10

Our previous research investigated the sensitivity of combustion phasing to intake temperature and injection timing during the transition from homogeneous charge compression ignition (HCCI) to partially premixed combustion (PPC) fuelled with generic gasoline. The results directed particular attention to the relationship between intake temperature and combustion phasing which reflected the changing of stratification level with the injection timing. To confirm its applicability with the use of different fuels, and to investigate the effect of fuel properties on stratification formation, primary reference fuels (PRF) were tested using the same method: a start of injection sweep from -180° to -20° after top dead center with constant combustion phasing by tuning the intake temperature. The present results are further developed compared with those of our previous work, which were based on generic gasoline. In the present work, a three-stage fuel-air stratification development process was observed during the transition from HCCI to PPC. Moreover, a transition stage was observed between the HCCI and PPC stages. Within this transition stage, both the combustion and emission characteristics deteriorated. The allocation of this transition area was mainly determined by the geometric design of the fuel injector and combustion chamber. Some differences in charge stratification were observed between the PRF and gasoline. The NO emissions of the PRF were comparable to those of gasoline. However, the NO emissions surged during the transition stage, indicating that the PRF combustion was probably more stratified. The soot emissions from PRF and gasoline were both much higher in the PPC than the HCCI mode, though the PRF produced much less soot than did gasoline in the PPC mode.

Mode transition and change in variable use in perceptual learning

NARCIS (Netherlands)

Hajnal, A; Grocki, M; Jacobs, DM; Zaal, FTJM; Michaels, CF

2006-01-01

Runeson, Justin, and Olsson (2000) proposed (a) that perceptual learning entails a transition from an inferential to a direct-perceptual mode of apprehension, and (b) that relative confidence-the difference between estimated and actual performance-indicates whether apprehension is inferential or

Mode transition and change in variable use in perceptual learning

NARCIS (Netherlands)

Hajnal, A.; Grocki, M.; Jacobs, D.M.; Zaal, F.T.J.M.; Michaels, C.F.

2006-01-01

Runeson, Juslin, and Olsson (2000) proposed (a) that perceptual learning entails a transition from an inferential to a direct-perceptual mode of apprehension, and (b) that relative confidence - the difference between estimated and actual performance - indicates whether apprehension is inferential or

Entropy as a collective variable

Science.gov (United States)

Parrinello, Michele

Sampling complex free energy surfaces that exhibit long lived metastable states separated by kinetic bottlenecks is one of the most pressing issues in the atomistic simulations of matter. Not surprisingly many solutions to this problem have been suggested. Many of them are based on the identification of appropriate collective variables that span the manifold of the slow varying modes of the system. While much effort has been put in devising and even constructing on the fly appropriate collective variables there is still a cogent need of introducing simple, generic, physically transparent, and yet effective collective variables. Motivated by the physical observation that in many case transitions between one metastable state and another result from a trade off between enthalpy and entropy we introduce appropriate collective variables that are able to represent in a simple way these two physical properties. We use these variables in the context of the recently introduced variationally enhanced sampling and apply it them with success to the simulation of crystallization from the liquid and to conformational transitions in protein. Department of Chemistry and Applied Biosciences, ETH Zurich, and Facolta' di Informatica, Istituto di Scienze Computazionali, Universita' della Svizzera Italiana, Via G. Buffi 13, 6900 Lugano, Switzerland.

Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate--The effects of street sweeping, vacuum cleaning, high pressure washing, and milling.

Science.gov (United States)

Winston, Ryan J; Al-Rubaei, Ahmed M; Blecken, Godecke T; Viklander, Maria; Hunt, William F

2016-03-15

The surface infiltration rates (SIR) of permeable pavements decline with time as sediment and debris clog pore spaces. Effective maintenance techniques are needed to ensure the hydraulic functionality and water quality benefits of this stormwater control. Eight different small-scale and full-scale maintenance techniques aimed at recovering pavement permeability were evaluated at ten different permeable pavement sites in the USA and Sweden. Maintenance techniques included manual removal of the upper 2 cm of fill material, mechanical street sweeping, regenerative-air street sweeping, vacuum street sweeping, hand-held vacuuming, high pressure washing, and milling of porous asphalt. The removal of the upper 2 cm of clogging material did not significantly improve the SIR of concrete grid paves (CGP) and permeable interlocking concrete pavers (PICP) due to the inclusion of fines in the joint and bedding stone during construction, suggesting routine maintenance cannot overcome improper construction. For porous asphalt maintenance, industrial hand-held vacuum cleaning, pressure washing, and milling were increasingly successful at recovering the SIR. Milling to a depth of 2.5 cm nearly restored the SIR for a 21-year old porous asphalt pavement to like-new conditions. For PICP, street sweepers employing suction were shown to be preferable to mechanical sweepers; additionally, maintenance efforts may become more intensive over time to maintain a threshold SIR, as maintenance was not 100% effective at removing clogging material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of hydrogen addition to a sweep gas on tritium behavior in a blanket module containing Li{sub 2}TiO{sub 3} pebbles

Energy Technology Data Exchange (ETDEWEB)

Katayama, K., E-mail: kadzu@nucl.kyushu-u.ac.jp [Department of Advanced Energy Engineering Science, Kyushu University 6-1, Kasugakoen, Kasuga-shi, Fukuoka 816-8580 (Japan); Someya, Y.; Tobita, K. [National Institutes for Quantum and radiological Science and Technology, 2-166 Omotedate, Obuchi, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Fukada, S. [Department of Advanced Energy Engineering Science, Kyushu University 6-1, Kasugakoen, Kasuga-shi, Fukuoka 816-8580 (Japan); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Chikada, T. [Department of Chemistry, Graduate school of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529 (Japan)

2016-12-15

Highlights: • Mass balance equations of H{sub 2}, H{sub 2}O, T{sub 2} and T{sub 2}O in a Li{sub 2}TiO{sub 3} pebble bed were numerically calculated. • In the temperature rising process, the pebbles were exposed to water vapor of relatively high concentration. • Tritium permeation rate to cooling water reduced with increasing hydrogen concentration in the sweep gas. • Tritium inventory in the grain bulk and the grain surface occupied 99.6% of total inventory. - Abstract: Hydrogen addition to a sweep gas of a solid breeder blanket module has been proposed to enhance tritium recovery from the surface of the breeders. However, the influence of hydrogen addition on the bred tritium behavior is not understood completely. Tritium behavior in the simplified blanket module of Li{sub 2}TiO{sub 3} pebbles was numerically calculated considering diffusion in the grain bulk, surface reactions on the grain surface and permeation through the cooling pipe. Although a partial pressure of T{sub 2} increases with increasing a partial pressure of H{sub 2} in the sweep gas, it was estimated that tritium permeation rate to the cooling water decreases. Additionally, the release duration of water vapor generated by the reaction of the pebbles and hydrogen is shortened with increasing a partial pressure of H{sub 2}. Tritium inventory in the grain bulk and the grain surface occupies 99.6 % of total tritium inventory in the blanket module.

Current-induced metal-insulator transition in VO x thin film prepared by rapid-thermal-annealing

International Nuclear Information System (INIS)

Cho, Choong-Rae; Cho, SungIl; Vadim, Sidorkin; Jung, Ranju; Yoo, Inkyeong

2006-01-01

The phenomenon of metal-insulator transition (MIT) in polycrystalline VO x thin films and their preparations have been studied. The films were prepared by sputtering of vanadium thin films succeeded by Rapid Thermal Annealing (RTA) in oxygen ambient at 500 deg. C. Crystalline, compositional, and morphological characterizations reveal a continuous change of phase from vanadium metal to the highest oxide phase, V 2 O 5 , with the time of annealing. Electrical MIT switching has been observed in these films. Sweeping mode, electrode area, and temperature dependent MIT has been studied in Pt/VO x /Pt vertical structure. The important parameters for MIT in VO x have been found to be the current density and the electric field, which depend on carrier density in the films

Evaluation on sweep gas pressure drop in fusion blanket mock-up for in-pile test

International Nuclear Information System (INIS)

Ishitsuka, Etsuo; Kawamura, Hiroshi; Sagawa, Hisashi; Nagakura, Masaaki; Kanzawa, Toru.

1993-03-01

In the ITER/CDA (Conceptual Design Activity) of a tritium breeding blanket, Japan have proposed the pebble-typed blanket. The in-pile mock-up test will be preparing in JMTR (Japan Materials Testing Reactor) for Japanese engineering design with the pebble-typed blanket. Therefore, the He sweep gas pressure drop in the pebble bed was measured for the design of the mock-up used on in-pile test. From the results of this test, it was clear that the pressure drop was predicted on Kozeny- Carman's equation within +25 ∼ -60 %, and that the pressure drop was not affected by moisture concentration (< 100 ppm). (author)

Evaluation on sweep gas pressure drop in fusion blanket mock-up for in-pile test

Energy Technology Data Exchange (ETDEWEB)

Ishitsuka, Etsuo; Kawamura, Hiroshi; Sagawa, Hisashi (Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment); Nagakura, Masaaki; Kanzawa, Toru.

1993-03-01

In the ITER/CDA (Conceptual Design Activity) of a tritium breeding blanket, Japan have proposed the pebble-typed blanket. The in-pile mock-up test will be preparing in JMTR (Japan Materials Testing Reactor) for Japanese engineering design with the pebble-typed blanket. Therefore, the He sweep gas pressure drop in the pebble bed was measured for the design of the mock-up used on in-pile test. From the results of this test, it was clear that the pressure drop was predicted on Kozeny- Carman's equation within +25 [approx] -60 %, and that the pressure drop was not affected by moisture concentration (< 100 ppm). (author).

Evaluation on sweep gas pressure drop in fusion blanket mock-up for in-pile test

Energy Technology Data Exchange (ETDEWEB)

Ishitsuka, Etsuo; Kawamura, Hiroshi; Sagawa, Hisashi [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Nagakura, Masaaki; Kanzawa, Toru

1993-03-01

In the ITER/CDA (Conceptual Design Activity) of a tritium breeding blanket, Japan have proposed the pebble-typed blanket. The in-pile mock-up test will be preparing in JMTR (Japan Materials Testing Reactor) for Japanese engineering design with the pebble-typed blanket. Therefore, the He sweep gas pressure drop in the pebble bed was measured for the design of the mock-up used on in-pile test. From the results of this test, it was clear that the pressure drop was predicted on Kozeny- Carman`s equation within +25 {approx} -60 %, and that the pressure drop was not affected by moisture concentration (< 100 ppm). (author).

THE QUASIPERIODIC AUTOMATED TRANSIT SEARCH ALGORITHM

International Nuclear Information System (INIS)

Carter, Joshua A.; Agol, Eric

2013-01-01

We present a new algorithm for detecting transiting extrasolar planets in time-series photometry. The Quasiperiodic Automated Transit Search (QATS) algorithm relaxes the usual assumption of strictly periodic transits by permitting a variable, but bounded, interval between successive transits. We show that this method is capable of detecting transiting planets with significant transit timing variations without any loss of significance— s mearing — as would be incurred with traditional algorithms; however, this is at the cost of a slightly increased stochastic background. The approximate times of transit are standard products of the QATS search. Despite the increased flexibility, we show that QATS has a run-time complexity that is comparable to traditional search codes and is comparably easy to implement. QATS is applicable to data having a nearly uninterrupted, uniform cadence and is therefore well suited to the modern class of space-based transit searches (e.g., Kepler, CoRoT). Applications of QATS include transiting planets in dynamically active multi-planet systems and transiting planets in stellar binary systems.

Variability in population abundance is associated with thresholds between scaling regimes

Science.gov (United States)

Wardwell, D.; Allen, Craig R.

2009-01-01

Discontinuous structure in landscapes may result in discontinuous, aggregated species body-mass patterns, reflecting the scales of structure available to animal communities within a landscape. The edges of these body-mass aggregations reflect transitions between available scales of landscape structure. Such transitions, or scale breaks, are theoretically associated with increased biological variability. We hypothesized that variability in population abundance is greater in animal species near the edge of body-mass aggregations than it is in species that are situated in the interior of body-mass aggregations. We tested this hypothesis by examining both temporal and spatial variability in the abundance of species in the bird community of the Florida Everglades sub-ecoregion, USA. Analyses of both temporal and spatial variability in population abundance supported our hypothesis. Our results indicate that variability within complex systems may be non-random, and is heightened where transitions in scales of process and structure occur. This is the first explicit test of the hypothetical relationship between increased population variability and scale breaks. ?? 2009 by the author(s).

Understanding Brown Dwarf Variability

Science.gov (United States)

Marley, Mark S.

2013-01-01

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

Simulating Linear Sweep Voltammetry from First-Principles: Application to Electrochemical Oxidation of Water on Pt(111) and Pt₃Ni(111)

DEFF Research Database (Denmark)

Viswanathan, Venkatasubramanian; Hansen, Heine Anton; Rossmeisl, Jan

2012-01-01

Cyclic voltammetry is a fundamental experimental method for characterizing adsorbates on electrochemical surfaces. We present a model for the electrochemical solid–liquid interface, and we simulate the linear sweep voltammogram of the electrochemical oxidation of H2O on Pt(111) and Pt3Ni(111...

Intensive Variables & Nanostructuring in Magnetostructural Materials

Energy Technology Data Exchange (ETDEWEB)

Lewis, Laura

2014-08-13

Over the course of this project, fundamental inquiry was carried out to investigate, understand and predict the effects of intensive variables, including the structural scale, on magnetostructural phase transitions in the model system of equiatomic FeRh. These transitions comprise simultaneous magnetic and structural phase changes that have their origins in very strong orbital-lattice coupling and thus may be driven by a plurality of effects.

NGC 3312: A victim of ram pressure sweeping

International Nuclear Information System (INIS)

Mcmahon, P.M.; Richter, O.G.; Vangorkom, J.H.; Ferguson, H.C.

1990-01-01

Researchers are undertaking a volume limited survey of the Hydra I cluster in neutral hydrogen using the National Radio Astronomy Observatory's Very Large Array (VLA). The main purpose is to study the effects of a dense environment on the gaseous component of the galaxies. Observational evidence has been accumulating recently that ram pressure sweeping does occur in the centers of clusters, but it is possible that tidal interactions play a role as well. Results of high resolution HI imaging of NGC 3312, the large peculiar spiral near the cluster center are presented. Hydra I (= A1060) is the nearest rich cluster beyond Virgo and, as such, presents a unique opportunity to do a complete survey of a cluster. It is similar to the Virgo cluster in many of its general physical characteristics, such as size, x ray luminosity, velocity dispersion, and galaxy content (high spiral fraction). However, Hydra I appears to be more regular and relaxed. This is evident in the x ray distribution in its central region, which is radially symmetric and centered on the dominant galaxy, NGC 3311, a cD-like elliptical. The observed x ray luminosity implies a central gas density of 4.5 x 10 to the 3rd power cm(-3). Gallagher (1978) argued from optical images of NGC 3312 that this galaxy might be an ideal candidate to directly study effects of the ram pressure process; it might currently be undergoing stripping of its interstellar medium. The researchers' data are consistent with this suggestion, but other origins of the peculiar appearance cannot yet be ruled out

Security Transition Program Office (STPO), technology transfer of the STPO process, tools, and techniques

Energy Technology Data Exchange (ETDEWEB)

Hauth, J.T.; Forslund, C.R.J.; Underwood, J.A.

1994-09-01

In 1990, with the transition from a defense mission to environmental restoration, the U.S. Department of Energy`s (DOE`s) Hanford Site began a significant effort to diagnose, redesign, and implement new safeguards and security (SAS) processes. In 1992 the Security Transition Program Office (STPO) was formed to address the sweeping changes that were being identified. Comprised of SAS and other contractor staff with extensive experience and supported by staff experienced in organizational analysis and work process redesign, STPO undertook a series of tasks designed to make fundamental changes to SAS processes throughout the Hanford Site. The goal of STPO is to align the SAS work and organization with the new Site mission. This report describes the key strategy, tools, methods, and techniques used by STPO to change SAS processes at Hanford. A particular focus of this review is transferring STPO`s experience to other DOE sites and federal agency efforts: that is, to extract, analyze, and provide a critical review of the approach, tools, and techniques used by STPO that will be useful to other DOE sites and national laboratories in transitioning from a defense production mode to environmental restoration and other missions. In particular, what lessons does STPO provide as a pilot study or model for implementing change in other transition activities throughout the DOE complex? More broadly, what theoretical and practical contributions do DOE transition efforts, such as STPO, provide to federal agency streamlining efforts and attempts to {open_quotes}reinvent{close_quotes} government enterprises in the public sector? The approach used by STPO should provide valuable information to those examining their own processes in light of new mission requirements.

Investigation at Low Speeds of the Effect of Aspect Ratio and Sweep on Rolling Stability Derivatives of Untapered Wings

Science.gov (United States)

Goodman, Alex; Fisher, Lewis R

1950-01-01

A low-scale wind-tunnel investigation was conducted in rolling flow to determine the effects of aspect ratio and sweep (when varied independently) on the rolling stability derivatives for a series of untapered wings. The rolling-flow equipment of the Langley stability tunnel was used for the tests. The data of the investigation have been used to develop a method of accounting for the effects of the drag on the yawing moment due to rolling throughout the lift range.

European transition to a low carbon electricity system using a mix of variable renewable energies: carbon saving trajectories as functions of production and storage capacity.

Science.gov (United States)

Francois, Baptiste; Creutin, Jean-Dominique

2016-04-01

Today, most of the produced energy is generated from fossil energy sources (i.e. coal, petroleum). As a result, the energy sector is still the main source of greenhouse gas in the atmosphere. For limiting greenhouse gas emission, a transition from fossil to renewable energy is required, increasing gradually the fraction energy coming from variable renewable energy (i.e. solar power, wind power and run-of-the river hydropower, hereafter denoted as VRE). VRE penetration, i.e. the percentage of demand satisfied by variable renewables assuming no storage capacity, is hampered by their variable and un-controllable features. Many studies show that combining different VRE over space smoothes their variability and increases their global penetration by a better match of demand fluctuations. When the demand is not fully supplied by the VRE generation, backup generation is required from stored energy (mostly from dams) or fossil sources, the latter being associated with high greenhouse gas emission. Thus the VRE penetration is a direct indicator of carbon savings and basically depends on the VRE installed capacity, its mix features, and on the installed storage capacity. In this study we analyze the European transition to a low carbon electricity system. Over a selection of representative regions we analyze carbon saving trajectories as functions of VRE production and storage capacities for different scenarios mixing one to three VRE with non-renewables. We show substantial differences between trajectories when the mix of sources is far from the local optimums, when the storage capacity evolves. We bring new elements of reflection about the effect of transport grid features from local independent systems to a European "copper plate". This work is part of the FP7 project COMPLEX (Knowledge based climate mitigation systems for a low carbon economy; Project FP7-ENV-2012 number: 308601; http://www.complex.ac.uk/).

Método de varredura para exame de criadouros de vetores de dengue e febre amarela urbana Sweeping method to scan breeding places for dengue and urban yellow fever vectors

Directory of Open Access Journals (Sweden)

Roseane Lieko Kubota

2003-04-01

Full Text Available Com objetivo de estimar o número mínimo de varreduras para coletar uma amostra representativa das larvas presentes em um grande recipiente, foram adicionadas 200 larvas de quarto estádio em um tambor de 80 litros de água. Com auxílio de peneira plástica, foram feitas dez varreduras em cada réplica do experimento. Os resultados indicaram que oito varreduras foram suficientes para coletar até 72% do total de 200 larvas de quarto estadio presentes no criadouro, ou seja, uma média de 143±1,97. A técnica mostrou ser de fácil e eficiente execução quanto à inspeção de criadouros com grande volume de água. Isto reforça sua utilização como instrumento com grande potencial para vigilância vetorial na rotina dos programas de controle de vetores do dengue e febre amarela.To estimate the minimum numbers of "sweepings" for a representative sampling of larvae in a large container. 200 larvae in 4th stage were added in an 80-liter drum to carry out the experiment, in each retort was made 10 sweepings using a plastic sieve. Two hundred larvae in stage 4 were added to an 80-liter-drum and using a plastic sieve10 sweepings were carried out in each experiment replicate. The results showed that 8 sweepings were enough to collect up to 72% of the total sample in the container, i.e., an average of 143±1.97. The proposed method proved to be easily and effectively implemented and allowed for the inspection of containers with large water volumes. These findings reinforce its use as an important potential tool in the routine vectorial surveillance of control programs of dengue and yellow fever.

The Influence of Sweep on the Aerodynamic Loading of an Oscillating NACA0012 Airfoil. Volume 2: Data Report

Science.gov (United States)

St.hilaire, A. O.; Carta, F. O.

1979-01-01

The effect of sweep on the dynamic response of the NACA 0012 airfoil was investigated. Unsteady chordwise distributed pressure data were obtained from a tunnel spanning wing equipped with 21 single surface transducers (13 on the suction side and 8 on the pressure side of the airfoil). The pressure data were obtained at pitching amplitudes of 8 and 10 degrees over a tunnel Mach number range of 0.10 to 0.46 and a pitching frequency range of 2.5 to 10.6 cycles per second. The wing was oscillated in the unswept and swept positions about the quarter-chord pivot axis relative to mean incidence angle settings of 0, 9, 12, and 15 degrees. A compilation of all the response data obtained during the test program is presented. These data are in the form of normal force, chord force, lift force, pressure drag, and moment hysteresis loops derived from chordwise integrations of the unsteady pressure distributions. The hysteresis loops are organized in two main sections. In the first section, the loop data are arranged to show the effect of sweep (lambda = 0 and 30 deg) for all available combinations of mean incidence angle, pitching amplitude, reduced frequency, and chordwise Mach number. The second section shows the effect of chordwise Mach number (MC = 0.30 and MC = 0.40) on the swept wing response for all available combinations of mean incidence angle, pitching amplitude, and reduced frequency.

Hitchhiking and Selective Sweeps of Plasmodium falciparum Sulfadoxine and Pyrimethamine Resistance Alleles in a Population from Central Africa▿ †

Science.gov (United States)

McCollum, Andrea M.; Basco, Leonardo K.; Tahar, Rachida; Udhayakumar, Venkatachalam; Escalante, Ananias A.

2008-01-01

Sulfadoxine-pyrimethamine (SP) resistance in Plasmodium falciparum is encoded by a number of mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes. Here, we have characterized point mutations in dhfr and dhps and microsatellite loci around dhfr on chromosome 4 and dhps on chromosome 8 as well as neutral markers on chromosomes 2 and 3 in 332 samples from Yaoundé, Cameroon. The triple mutant dhfr haplotype that originated in Southeast Asia is the most predominant in this sample set, but we also find additional independent haplotypes at low frequency and an incipient process of genetic differentiation among alleles of Southeast Asian origin. As reported for other African populations, we find evidence of a selective sweep for resistant dhfr mutants in this Cameroonian population due to drug selection. Although we find evidence for a selective sweep in dhps mutants associated with SP resistance, the dynamics of dhps mutants appear different than those observed for dhfr mutants. Overall, our results yield support for the use of microsatellite markers to track resistant parasites; however, the detection of resistant dhfr alleles in low frequency, the evidence of divergence among dhfr alleles that share a common evolutionary origin, and the distinct dynamics of resistant dhps alleles emphasize the importance of comprehensive, population-based investigations to evaluate the effects of drug selection on parasite populations. PMID:18765692

Correlated radio and optical variability in the BL Lacertae object 0716 + 714

International Nuclear Information System (INIS)

Quirrenbach, A.; Witzel, A.; Krichbaum, T.P.; Wagner, S.; Sanchez-pons, F.

1991-01-01

Results are presented from simultaneous optical and radio observations of the BL Lacertae object 0716 + 714. During a 4-week period of continuous monitoring the source displayed in both wavelength regimes a transition between states of fast and slow variability with a change of the typical variability time scale from about 1 day to about 7 days. The simultaneous transition is interpreted as evidence for intrinsic source variability, and some consequences for the optical and radio emission regions are discussed. 19 refs

Production of artificial ionospheric layers by frequency sweeping near the 2nd gyroharmonic

Directory of Open Access Journals (Sweden)

T. Pedersen

2011-01-01

Full Text Available Artificial ionospheric plasmas descending from the background F-region have been observed on multiple occasions at the High Frequency Active Auroral Research Program (HAARP facility since it reached full 3.6 MW power. Proximity of the transmitter frequency to the 2nd harmonic of the electron gyrofrequency (2fce has been noted as a requirement for their occurrence, and their disappearance after only a few minutes has been attributed to the increasing frequency mismatch at lower altitudes. We report new experiments employing frequency sweeps to match 2fce in the artificial plasmas as they descend. In addition to revealing the dependence on the 2fce resonance, this technique reliably produces descending plasmas in multiple transmitter beam positions and appears to increase their stability and lifetime. High-speed ionosonde measurements are used to monitor the altitude and density of the artificial plasmas during both the formation and decay stages.

Variable depth recursion algorithm for leaf sequencing

International Nuclear Information System (INIS)

Siochi, R. Alfredo C.

2007-01-01

The processes of extraction and sweep are basic segmentation steps that are used in leaf sequencing algorithms. A modified version of a commercial leaf sequencer changed the way that the extracts are selected and expanded the search space, but the modification maintained the basic search paradigm of evaluating multiple solutions, each one consisting of up to 12 extracts and a sweep sequence. While it generated the best solutions compared to other published algorithms, it used more computation time. A new, faster algorithm selects one extract at a time but calls itself as an evaluation function a user-specified number of times, after which it uses the bidirectional sweeping window algorithm as the final evaluation function. To achieve a performance comparable to that of the modified commercial leaf sequencer, 2-3 calls were needed, and in all test cases, there were only slight improvements beyond two calls. For the 13 clinical test maps, computation speeds improved by a factor between 12 and 43, depending on the constraints, namely the ability to interdigitate and the avoidance of the tongue-and-groove under dose. The new algorithm was compared to the original and modified versions of the commercial leaf sequencer. It was also compared to other published algorithms for 1400, random, 15x15, test maps with 3-16 intensity levels. In every single case the new algorithm provided the best solution

Simultaneous Chandra and VLA Observations of the Transitional Millisecond Pulsar PSR J1023+0038: Anti-correlated X-Ray and Radio Variability

Science.gov (United States)

Bogdanov, Slavko; Deller, Adam T.; Miller-Jones, James C. A.; Archibald, Anne M.; Hessels, Jason W. T.; Jaodand, Amruta; Patruno, Alessandro; Bassa, Cees; D’Angelo, Caroline

2018-03-01

We present coordinated Chandra X-ray Observatory and Karl G. Jansky Very Large Array observations of the transitional millisecond pulsar PSR J1023+0038 in its low-luminosity accreting state. The unprecedented five hours of strictly simultaneous X-ray and radio continuum coverage for the first time unambiguously show a highly reproducible, anti-correlated variability pattern. The characteristic switches from the X-ray high mode into a low mode are always accompanied by a radio brightening with a duration that closely matches the X-ray low mode interval. This behavior cannot be explained by a canonical inflow/outflow accretion model where the radiated emission and the jet luminosity are powered by, and positively correlated with, the available accretion energy. We interpret this phenomenology as alternating episodes of low-level accretion onto the neutron star during the X-ray high mode that are interrupted by rapid ejections of plasma by the active rotation-powered pulsar, possibly initiated by a reconfiguration of the pulsar magnetosphere, that cause a transition to a less X-ray luminous mode. The observed anti-correlation between radio and X-ray luminosity has an additional consequence: transitional MSPs can make excursions into a region of the radio/X-ray luminosity plane previously thought to be occupied solely by black hole X-ray binary sources. This complicates the use of this luminosity relation for identifying candidate black holes, suggesting the need for additional discriminants when attempting to establish the true nature of the accretor.

Singlet Oxygen Production by Illuminated Road Dust and Winter Street Sweepings

Science.gov (United States)

Schneider, S.; Gan, L.; Gao, S.; Hoy, K. S.; Kwasny, J. R.; Styler, S. A.

2017-12-01

Road dust is an important urban source of primary particulate matter, especially in cities where sand and other traction materials are applied to roadways in winter. Although the composition and detrimental health effects of road dust are reasonably well characterized, little is currently known regarding its chemical behaviour. Motivated by our previous work, in which we showed that road dust is a photochemical source of singlet oxygen (1O2), we investigated 1O2 production by bulk winter street sweepings and by road dust collected in a variety of urban, industrial, and suburban locations in both autumn and spring. In all cases, the production of 1O2 by road dust was greater than that by Arizona test dust and desert-sourced dust, which highlights the unique photochemical environment afforded by this substrate. Mechanistically, we observed correlations between 1O2 production and the UV absorbance properties of dust extracts, which suggests the involvement of chromophoric dissolved organic matter in the observed photochemistry. Taken together, this work provides evidence that road dust-mediated photochemistry may influence the environmental lifetime of pollutants that react via 1O2-mediated pathways, including polycyclic aromatic hydrocarbons.

Using Variable-Length Aligned Fragment Pairs and an Improved Transition Function for Flexible Protein Structure Alignment.

Science.gov (United States)

Cao, Hu; Lu, Yonggang

2017-01-01

With the rapid growth of known protein 3D structures in number, how to efficiently compare protein structures becomes an essential and challenging problem in computational structural biology. At present, many protein structure alignment methods have been developed. Among all these methods, flexible structure alignment methods are shown to be superior to rigid structure alignment methods in identifying structure similarities between proteins, which have gone through conformational changes. It is also found that the methods based on aligned fragment pairs (AFPs) have a special advantage over other approaches in balancing global structure similarities and local structure similarities. Accordingly, we propose a new flexible protein structure alignment method based on variable-length AFPs. Compared with other methods, the proposed method possesses three main advantages. First, it is based on variable-length AFPs. The length of each AFP is separately determined to maximally represent a local similar structure fragment, which reduces the number of AFPs. Second, it uses local coordinate systems, which simplify the computation at each step of the expansion of AFPs during the AFP identification. Third, it decreases the number of twists by rewarding the situation where nonconsecutive AFPs share the same transformation in the alignment, which is realized by dynamic programming with an improved transition function. The experimental data show that compared with FlexProt, FATCAT, and FlexSnap, the proposed method can achieve comparable results by introducing fewer twists. Meanwhile, it can generate results similar to those of the FATCAT method in much less running time due to the reduced number of AFPs.

Long term changes in social metabolism and land use in Czechoslovakia, 1830-2000. An energy transition under changing political regimes

Energy Technology Data Exchange (ETDEWEB)

Kuskova, Petra [Department of Social Geography and Regional Development, Faculty of Science, Charles University in Prague (Czech Republic); Gingrich, Simone; Krausmann, Fridolin [Institute of Social Ecology, Faculty for Interdisciplinary Studies Vienna, Klagenfurt University (Austria)

2008-12-01

Industrialisation goes along with sweeping changes in society's interrelations with its environment. The transition from an agrarian to an industrial society leads to fundamentally new patterns in social metabolism, a process which has been described as socio-metabolic transition. This paper investigates this transition for the case of the current Czech and Slovak Republics and presents a dataset on the development of key variables related to social metabolism during the last 170 years. The dataset includes time series data on the extraction of biomass and fossil fuels, energy consumption and land use. Combining data on Bohemia and Moravia (1830-1915) with data on Czechoslovakia (1918-1992) and the Czech and Slovak Republics (1993-2002), the study covers a period of consecutive political and institutional changes. It includes the feudal regime of the late period of the Habsburg Empire and its disintegration with WWI, the short period of the Czechoslovak Republic in the interwar period, the era of a planned economy under a communist regime, the collapse of this regime and the subsequent turn towards a market economy and European integration in the 1990s. The period was characterized by economic and physical growth. It saw a doubling of population and a growth in GDP by a factor 20. Domestic energy consumption (DEC) increased by a factor 10 and the share of biomass in DEC declined from more than 98% to less than 20%. All in all the observed changes closely resemble the characteristic path of the socio-metabolic transition as observed in other Western European economies. Major political and economic changes did not result in fundamental alterations of the socio-metabolic transition until the mid-20th century. The communist era (1945-1989) was characterized by rapid physical growth and changes in the energy and land use system very similar to those of other Western European economies in the same period, however leading to DEC values substantially higher than those

Variability and Dynamics of Dissolved Oxygen in the Transition Zone of the North Sea and the Baltic Sea

DEFF Research Database (Denmark)

Jonasson, Lars

information about the seasonal to decadal oxygen variations in the bottom water of the Kattegat, the Danish Straits, the Sound and the Western Baltic Sea and investigates the relative importance of physical and biogeochemical processes, climate change and nutrient load reductions on the oxygen variability......The bottom water in the transition zone of the North Sea and Baltic Sea suffers from seasonal hypoxia, usually during late summer and autumn. Hypoxia is a natural phenomenon in this region because of the strong vertical stratification which prevents the bottom water to be ventilated by atmospheric...... concentrations by 15-30 μmol O2 l−1 yr−1 while the reduced nutrient concentration has increased the oxygen concentration with approximately the same amount. Thus, the positive effect on oxygen conditions from reduced nutrient concentrations have been counteracted by increased water temperatures. This has made...

Predicting weather regime transitions in Northern Hemisphere datasets

Energy Technology Data Exchange (ETDEWEB)

Kondrashov, D. [University of California, Department of Atmospheric and Oceanic Sciences and Institute of Geophysics and Planetary Physics, Los Angeles, CA (United States); Shen, J. [UCLA, Department of Statistics, Los Angeles, CA (United States); Berk, R. [UCLA, Department of Statistics, Los Angeles, CA (United States); University of Pennsylvania, Department of Criminology, Philadelphia, PA (United States); D' Andrea, F.; Ghil, M. [Ecole Normale Superieure, Departement Terre-Atmosphere-Ocean and Laboratoire de Meteorologie Dynamique (CNRS and IPSL), Paris Cedex 05 (France)

2007-10-15

A statistical learning method called random forests is applied to the prediction of transitions between weather regimes of wintertime Northern Hemisphere (NH) atmospheric low-frequency variability. A dataset composed of 55 winters of NH 700-mb geopotential height anomalies is used in the present study. A mixture model finds that the three Gaussian components that were statistically significant in earlier work are robust; they are the Pacific-North American (PNA) regime, its approximate reverse (the reverse PNA, or RNA), and the blocked phase of the North Atlantic Oscillation (BNAO). The most significant and robust transitions in the Markov chain generated by these regimes are PNA {yields} BNAO, PNA {yields} RNA and BNAO {yields} PNA. The break of a regime and subsequent onset of another one is forecast for these three transitions. Taking the relative costs of false positives and false negatives into account, the random-forests method shows useful forecasting skill. The calculations are carried out in the phase space spanned by a few leading empirical orthogonal functions of dataset variability. Plots of estimated response functions to a given predictor confirm the crucial influence of the exit angle on a preferred transition path. This result points to the dynamic origin of the transitions. (orig.)

Instability and Transition of Flow at, and Near, an Attachment-line - Including Control by Surface Suction

Science.gov (United States)

Smith, A.

1996-01-01

Advances in aviation during and following the Second World War led to an enormous improvement in the performance of aircraft. The push for enhanced efficiency brought cruise speeds into the transonic range, where the associated drag rise due to the appearance of shock-waves became a limiting factor. Wing sweep was adopted to delay the onset of this drag rise, but with this development came several new and unforeseen problems. Preliminary theoretical work assumed that the boundary layer transition characteristics of a swept wing would be subject to the independence principle, so the chordwise transition position could be predicted from two-dimensional work Gas turbine development has now reached a point where additional increases in efficiency are both difficult and expensive to achieve. Consequently, aircraft manufacturers are looking elsewhere for ways to reduce Direct Operating Costs (DOC's) or increase military performance. The attention of industry is currently focusing on Hybrid Laminar Flow Control (HLFC) as a possible method of reducing DOC's for civil aircraft. Following this study and discussions with NASA Langley and Boeing a different series of questions have been addressed in the present work. There are five areas of interest: Relaminarisation of the attachment-line boundary layer when the value of R exceeds 600. The effects of large suction levels on transition in the attachment-line boundary layer (ie critical oversuction). The transition characteristics of a relaminarised attachment-line flow which encounters a non-porous surface. The effect of attachment-line suction on the spanwise propagation of gross disturbances emanating from the wing-fuselage junction. The attachment-line transition caused by surface blowing.

The Temperature and Salinity Variabilities at Cisadane Estuary

Directory of Open Access Journals (Sweden)

Hadikusumah

2008-11-01

Full Text Available The study was conducted at Cisadane Estuary at 18 oceanographic station in Transition Monsoon Season I, East Monsoon Season, and Transition Monsoon Season II from 2003 to 2005. The area of the study was located at the longitude of 106.58° - 106.70° E and the latitude of 5.96° - 6.02°S. The measurements of temperature, salinity, tubidity and light transmision used CTD (Conductivity, Temperature and Depth Model SBE-19. The result shows that the temperature and salinity vertical profil variabilities at Cisadane Estuary underwent a change in the influence of Transition Monsoon Season I, East Monsoon Season, and Transition Monsoon Season II, for example it was obtained the leg time of the maximum salinity of Transition Monsoon Season II as the same as that of East Monsoon Season. Based on the horizontal and vertical distribution pattern analysis of the interaction between low salinity fresh water of Cisadane River and high salinity sea water of Java Sea, it was also influenced by the season variability and tide. The surface layer was much more influenced by the low salinity and the heat of sunray (seasonal variability with the weaker intensity to the lower layer. The change of the heat energy by the increase of seasonal temperature occurred in September 2003 to May 2004 ((ΔE = 600.6 ⋅ 105 Joule, July to November 2005 (ΔE = 84.9 Joule. The decrease of the heat energy occurred in June to September 2003 ((-267.6 ⋅ 105, May ke October 2004 (ΔE = 189.3 ⋅ 105 Joule and October 2004 to July 2005 (ΔE = -215.4 ⋅ 105 Joule.

The cognitive roles of behavioral variability: idiosyncratic acts as the foundation of identity and as transitional, preparatory, and confirmatory phases.

Science.gov (United States)

Eilam, David

2015-02-01

Behavior in obsessive compulsive disorder (OCD), in habitual daily tasks, and in sport and cultural rituals is deconstructed into elemental acts and categorized into common acts, performed by all individuals completing a similar task, and idiosyncratic acts, not performed by all individuals. Never skipped, common acts establish the pragmatic part of motor tasks. Repetitive performance of a few common acts renders rituals a rigid form, whereby common acts may serve as memes for cultural transmission. While idiosyncratic acts are not pragmatically necessary for task completion, they fulfill important cognitive roles. They form a long preparatory phase in tasks that involve high stakes, and a long confirmatory phase in OCD rituals. Idiosyncratic acts also form transitional phases between motor tasks, and are involved in establishing identity and preserving the flexibility necessary for adapting to varying circumstances. Behavioral variability, as manifested in idiosyncrasy, thus does not seem to be a noise or by-product of motor activity, but an essential cognitive component that has been preserved in the evolution of behavioral patterns, similar to the genetic variability in biology. Copyright © 2014 Elsevier Ltd. All rights reserved.

SIMPLE-2: a computer code for calculation of steady-state thermal behavior of rod bundles with flow sweeping

International Nuclear Information System (INIS)

Jones, O.C. Jr.; Yao, S.; Henry, R.E.

1976-01-01

A computer code has been developed for use in making single-phase thermal hydraulic calculations in rod bundle arrays with flow sweeping due to spiral wraps as the predominant crossflow mixing effect. This code, called SIMPLE-2, makes the assumption that the axial pressure gradient is identical for each subchannel over a given axial increment, and is unique in that no empirical coefficients must be specified for its use. Results from this code have been favorably compared with experimental data for both uniform and highly nonuniform power distributions. Typical calculations for various bundle sizes applicable to the LMBR program are included

Frequency sweep of the field scattered by an inhomogeneous structure using method of moments and asymptotic waveform evaluation

DEFF Research Database (Denmark)

Troelsen, Jens; Meincke, Peter; Breinbjerg, Olav

2000-01-01

into account. To the knowledge of the authors the AWE technique has not previously been applied to a MoM solution based on this kind of integral equation. It is the purpose of this paper to investigate the use of the AWE technique as a tool to obtain a fast frequency sweep of the field scattered......In many radar applications it is necessary to determine the scattering from an object over a wide frequency band. The asymptotic waveform evaluation (AWE), which is a moment matching (MM) technique, constitutes a method to this end. In general, MM techniques provide a reduced-order model...

Selection Bias in Educational Transition Models: Theory and Empirical Evidence

DEFF Research Database (Denmark)

Holm, Anders; Jæger, Mads

variables. This paper, first, explains theoretically how selection on unobserved variables leads to waning coefficients and, second, illustrates empirically how selection leads to biased estimates of the effect of family background on educational transitions. Our empirical analysis using data from...

Magnetovoltage Measurements and Field Sweep Rate Dependence of V-H curves in Superconducting Polycrystalline Y1Ba2Cu3O7-x

International Nuclear Information System (INIS)

Yetis, H; Altinkok, A; Olutas, M; Kilic, A; Kilic, K; Cetin, O

2006-01-01

Magnetovoltage measurements (V-H curves) were carried out in superconducting polycrystalline bulk Y 1 Ba 2 Cu 3 O 7-x (YBCO) material as a function of current (I), temperature (T), field sweep rate (dH/dt) and field orientation with respect to the transport current. A relative decrease in the dissipation measured in V-H curves was observed as dH/dt is increased, which implies that the time spent to plot the whole cycle has an importance on the evolution of the V-H curves. Thus, it could be possible to observe the relaxation effects in magnetovoltage measurements. In addition, the several significant steps and plateaus in V-H curves evolve depending on the magnitude of the transport current and also dH/dt. These observations were attributed to locking of the flux lines to decrease or increase in size of the easy motion flow channels. The strong hysteresis effects in V-H curves were discussed mainly by means of the flux trapping within the granularity of sample and the different degree of the inhomogeneous flux motion with respect to the sweeping of the external magnetic field up and down

Broadband W-band Rapid Frequency Sweep Considerations for Fourier Transform EPR.

Science.gov (United States)

Strangeway, Robert A; Hyde, James S; Camenisch, Theodore G; Sidabras, Jason W; Mett, Richard R; Anderson, James R; Ratke, Joseph J; Subczynski, Witold K

2017-12-01

A multi-arm W-band (94 GHz) electron paramagnetic resonance spectrometer that incorporates a loop-gap resonator with high bandwidth is described. A goal of the instrumental development is detection of free induction decay following rapid sweep of the microwave frequency across the spectrum of a nitroxide radical at physiological temperature, which is expected to lead to a capability for Fourier transform electron paramagnetic resonance. Progress toward this goal is a theme of the paper. Because of the low Q-value of the loop-gap resonator, it was found necessary to develop a new type of automatic frequency control, which is described in an appendix. Path-length equalization, which is accomplished at the intermediate frequency of 59 GHz, is analyzed. A directional coupler is favored for separation of incident and reflected power between the bridge and the loop-gap resonator. Microwave leakage of this coupler is analyzed. An oversize waveguide with hyperbolic-cosine tapers couples the bridge to the loop-gap resonator, which results in reduced microwave power and signal loss. Benchmark sensitivity data are provided. The most extensive application of the instrument to date has been the measurement of T 1 values using pulse saturation recovery. An overview of that work is provided.

Bio-inspired online variable recruitment control of fluidic artificial muscles

Science.gov (United States)

Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

2016-12-01

This paper details the creation of a hybrid variable recruitment control scheme for fluidic artificial muscle (FAM) actuators with an emphasis on maximizing system efficiency and switching control performance. Variable recruitment is the process of altering a system’s active number of actuators, allowing operation in distinct force regimes. Previously, FAM variable recruitment was only quantified with offline, manual valve switching; this study addresses the creation and characterization of novel, on-line FAM switching control algorithms. The bio-inspired algorithms are implemented in conjunction with a PID and model-based controller, and applied to a simulated plant model. Variable recruitment transition effects and chatter rejection are explored via a sensitivity analysis, allowing a system designer to weigh tradeoffs in actuator modeling, algorithm choice, and necessary hardware. Variable recruitment is further developed through simulation of a robotic arm tracking a variety of spline position inputs, requiring several levels of actuator recruitment. Switching controller performance is quantified and compared with baseline systems lacking variable recruitment. The work extends current variable recruitment knowledge by creating novel online variable recruitment control schemes, and exploring how online actuator recruitment affects system efficiency and control performance. Key topics associated with implementing a variable recruitment scheme, including the effects of modeling inaccuracies, hardware considerations, and switching transition concerns are also addressed.

Composição de resíduos de varrição e resíduos carreados pela rede de drenagem, em uma bacia hidrográfica urbana Litter composition delivered by street sweeping and by the storm drainage network, in an urban catchment

Directory of Open Access Journals (Sweden)

Marllus Gustavo Ferreira Passos das Neves

2011-12-01

Full Text Available Apresentam-se aqui resultados de estudo sobre a composição física de resíduos sólidos de varrição e também daqueles vindos por uma rede de drenagem, em uma bacia hidrográfica urbana, identificando, dentre outros, influências da frequência do serviço de varrição e da época do ano. Os resíduos de varrição foram provenientes de várias partes do solo da bacia e os da rede de drenagem eram retirados de um poço de casa de bombas, para onde convergia todo o escoamento da rede. Alguns resultados interessantes: em média, 23% da massa de varrição são de lixo seco, predominando plásticos moles. Mais presença de plásticos duros ocorreu nas áreas de varrição diária. Com a análise dos resíduos vindos pela drenagem: o plástico Pet apareceu mais na rede em precipitações intensas do que nos sacos de varrição. Plásticos moles sempre ocorrem na varrição e na drenagem ao longo do ano.This paper presents results of a study about physical composition of litter from street sweeping and also those delivered by a storm drainage network urban catchment, identifying, among others, influences of the frequency of sweeping service and the season. The litter from sweeping came from several parts of the catchment and those delivered by a storm drainage network were taken from a well pump house, convergence point of the flow. Some interesting results: on average, 23% of the street sweeping mass is dry litter, predominantly soft plastics. More presence of hard plastics occurred at areas of daily sweeping. With the analysis of litter in the storm drainage network: pet plastics are more delivered by storm drainage network in intense rainfall than appear in bags sweeping. Soft plastics always occur in the bags sweeping and into storm drainage network throughout the year.

Photometric Variability of the Be Star Population

International Nuclear Information System (INIS)

Labadie-Bartz, Jonathan; Pepper, Joshua; McSwain, M. Virginia; Bjorkman, J. E.; Bjorkman, K. S.; Lund, Michael B.; Rodriguez, Joseph E.; Stassun, Keivan G.; Stevens, Daniel J.; James, David J.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.

2017-01-01

Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.

Photometric Variability of the Be Star Population

Energy Technology Data Exchange (ETDEWEB)

Labadie-Bartz, Jonathan; Pepper, Joshua; McSwain, M. Virginia [Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA 18015 (United States); Bjorkman, J. E.; Bjorkman, K. S. [Ritter Observatory, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft, Toledo, OH 43606-3390 (United States); Lund, Michael B.; Rodriguez, Joseph E.; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Stevens, Daniel J. [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); James, David J. [Cerro Tololo Inter-American Observatory, Casilla 603 La Serena (Chile); Kuhn, Rudolf B. [Southern African Large Telescope, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Siverd, Robert J. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Beatty, Thomas G. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

2017-06-01

Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.

Pre-inflation: Origin of the Universe from a topological phase transition

Directory of Open Access Journals (Sweden)

Mauricio Bellini

2017-08-01

Full Text Available I study a model which describes the birth of the universe using a global topological phase transition with a complex manifold where the time, τ, is considered as a complex variable. Before the big bang τ is a purely imaginary variable so that the space can be considered as Euclidean. The phase transition from a pre-inflation to inflation is examined by studying the dynamical rotation of the time on the complex plane. Back-reaction effects are exactly calculated using Relativistic Quantum Geometry.

High-Fidelity Aerodynamic Design with Transition Prediction, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — To enhance aerodynamic design capabilities, Desktop Aeronautics proposes to significantly improve upon the integration (performed in Phase 1) of a new sweep/taper...

Field-amplified sample stacking-sweeping of vitamins B determination in capillary electrophoresis.

Science.gov (United States)

Dziomba, Szymon; Kowalski, Piotr; Bączek, Tomasz

2012-12-07

A capillary electrophoretic method for determination of five water soluble vitamins B along with baclofen as an internal standard has been developed and assessed in context of precision, accuracy, sensitivity, freedom from interference, linearity, detection and quantification limits. On-line preconcentration technique, namely field-amplified sample stacking (FASS)-sweeping, has been employed in respect to obtain more sensitive analysis. Separation conditions received after optimization procedure were as following background electrolyte (BGE), 10 mM NaH(2)PO(4), 80 mM SDS, (pH 7.25); sample matrix (SM), 10 mM NaH(2)PO(4) (pH 4.60); uncoated fused silica capillary (50 μm i.d. × 67 cm length); UV spectrophotometric detection at 200 nm; injection times: 10s and 30s at 3.45 kPa; applied voltage 22 kV; temperature 22°C. Validation parameters, namely precision, accuracy and linearity, were considered as satisfactory. Under the optimized conditions, it has been also successfully applied for vitamins B determination in bacterial growth medium and commercially available Ilex paraguariensis leaves. Copyright © 2012 Elsevier B.V. All rights reserved.

Engasgamento em bebês após busca às cegas com os dedos Infants choking following blind finger sweep

Directory of Open Access Journals (Sweden)

Hasan A. Abder-Rahman

2009-06-01

Full Text Available OBJETIVO: Em situações estressantes, as pessoas geralmente usam os dedos para retirar corpos estranhos de faringe da boca. Este artigo relata três casos de óbito de bebês após o uso dessa técnica. MÉTODOS: Um total de 26 casos de engasgamento causado por aspiração de corpos estranhos nas vias respiratórias superiores e inferiores envolvendo crianças menores de 11 anos submetidas a autopsia no Departamento de Medicina Forense da Universidade da Jordânia entre 1996 e 2006 foram revisados. RESULTADOS: O uso de busca às cegas com os dedos para retirar corpos estranhos de faringe foi relatado em três bebês durante o choro. Todas as crianças eram menores de 1 ano e haviam se engasgado com grãos-de-bico, uma bola de gude e um lápis curto. A diversidade, o tamanho, a forma, e a maciez da superfície são as principais características que fazem com que esses corpos estranhos sejam mais difíceis de ser removidos com os dedos e facilitam sua entrada via respiratória. CONCLUSÃO: Esses casos mostraram que a busca às cegas com os dedos na boca de bebês durante o choro não é somente uma manobra perigosa, mas também pode ser fatal.OBJECTIVE: In stressful situations, people usually use finger sweep to remove pharyngeal foreign bodies from the mouth. This article reports on three cases of death of infants following the use of this technique. METHODS: A total of 26 cases of choking caused by foreign bodies aspiration in the upper and lower respiratory passages involving children younger than 11 years of age autopsied at the Forensic Department of University of Jordânia between 1996 and 2006 were reviewed. RESULTS: Blind finger sweep to remove pharyngeal foreign bodies were reported in three crying infants. All of these cases were younger than 1 year of age and choked on a chickpea, a marble and a short pencil. Diversity, size, shape and smoothness of the surface are the main characteristics that render the foreign bodies less easily

Quantum phase transitional patterns of nuclei

International Nuclear Information System (INIS)

Dai Lianrong; Wang Lixing; Pan Feng; Zhong Weiwei; Liu Qi

2013-01-01

With the framework of Interacting Boson Model (IBM), transitional patterns from the spherical to the axially deformed limit of the IBM with a schematic Hamiltonian are studied by replacing the SU (3) quadrupole-quadrupole term with O (6) cubic interaction. But, we use the two schemes to investigate some energy ratios and B (E2) ratios for different bosons N = 8 and N = 20. The results show that with the increasing of the numbers of bosons, the transitional behaviors can be enhanced; the transitional behaviors are very similar in the two schemes. However, there are some distinctive differences for some quantities across the entire transitional region, such as energy levels and ratios, B (E2) values and ratios, and expectation values of the shape variables. Generally speaking, the transition is smoother and the nuclear shape is less well defined in the new scheme. Then we apply the two schemes to the critical point symmetry candidate, such as 152 Sm, and find the overall fitting quality of the UQ scheme is better than that of the U (5)-SU (3) scheme, especially for the inter-band E2 transitions in 152 Sm. (authors)

Variable RF capacitor based on a-Si:H (P-doped) multi-length cantilevers

International Nuclear Information System (INIS)

Fu, Y Q; Milne, S B; Luo, J K; Flewitt, A J; Wang, L; Miao, J M; Milne, W I

2006-01-01

A variable RF capacitor with a-Si:H (doped with phosphine) cantilevers as the top electrode were designed and fabricated. Because the top multi-cantilever electrodes have different lengths, increasing the applied voltage pulled down the cantilever beams sequentially, thus realizing a gradual increase of the capacitance with the applied voltage. A high-k material, H f O 2 , was used as an insulating layer to increase the tuning range of the capacitance. The measured capacitance from the fabricated capacitor was much lower and the pull-in voltage was much higher than those from theoretical analysis because of incomplete contact of the two electrodes, existence of film differential stresses and charge injection effect. Increase of sweeping voltage rate could significantly shift the pull-in voltage to higher values due to the charge injection mechanisms

Women's employment transitions around child bearing.

Science.gov (United States)

Dex, S; Joshi, H; Macran, S; Mcculloch, A

1998-02-01

Women's increasing participation in the labor force since the 1950s demands that knowledge about their labor supply needs to keep pace with the changing world. One important change has occurred among mothers of small children, they are increasingly working for pay in successive generations, as the break in their employment has become increasingly shorter. Legislation was enacted in the UK to outlaw unequal pay and discrimination in employment on the basis of gender, while statutory maternity leave was introduced in 1976 and extended in 1986. The proportion of mothers taking maternity leave has since increased, as has full-time employment among mothers. The authors examine the transitions into and out of paid work which women make after childbirth, helping to determine whether recent generations of mothers have benefitted from the policy changes, whether all have benefitted equally, and whether any effects persist beyond the period around the first childbirth. Study data are drawn from the fifth sweep of the National Child Development Study (NCDS) 1958 birth cohort at age 33. The experiences of mothers in the 1958 generation suggests that women have begun to benefit from the equal opportunities provisions enacted in Britain during the 1970s. The age of the youngest child is the most important determinant of women's participation over the preschool years, and relatively better educated women have the highest degree of continuity in employment across childbirth.

Mechanistic Understanding of Microbial Plugging for Improved Sweep Efficiency

Energy Technology Data Exchange (ETDEWEB)

Steven Bryant; Larry Britton

2008-09-30

Microbial plugging has been proposed as an effective low cost method of permeability reduction. Yet there is a dearth of information on the fundamental processes of microbial growth in porous media, and there are no suitable data to model the process of microbial plugging as it relates to sweep efficiency. To optimize the field implementation, better mechanistic and volumetric understanding of biofilm growth within a porous medium is needed. In particular, the engineering design hinges upon a quantitative relationship between amount of nutrient consumption, amount of growth, and degree of permeability reduction. In this project experiments were conducted to obtain new data to elucidate this relationship. Experiments in heterogeneous (layered) beadpacks showed that microbes could grow preferentially in the high permeability layer. Ultimately this caused flow to be equally divided between high and low permeability layers, precisely the behavior needed for MEOR. Remarkably, classical models of microbial nutrient uptake in batch experiments do not explain the nutrient consumption by the same microbes in flow experiments. We propose a simple extension of classical kinetics to account for the self-limiting consumption of nutrient observed in our experiments, and we outline a modeling approach based on architecture and behavior of biofilms. Such a model would account for the changing trend of nutrient consumption by bacteria with the increasing biomass and the onset of biofilm formation. However no existing model can explain the microbial preference for growth in high permeability regions, nor is there any obvious extension of the model for this observation. An attractive conjecture is that quorum sensing is involved in the heterogeneous bead packs.

Acetate and phosphate anion adsorption linear sweep voltammograms simulated using density functional theory

KAUST Repository

Savizi, Iman Shahidi Pour

2011-04-01

Specific adsorption of anions to electrode surfaces may alter the rates of electrocatalytic reactions. Density functional theory (DFT) methods are used to predict the adsorption free energy of acetate and phosphate anions as a function of Pt(1 1 1) electrode potential. Four models of the electrode potential are used including a simple vacuum slab model, an applied electric field model with and without the inclusion of a solvating water bi-layer, and the double reference model. The linear sweep voltammogram (LSV) due to anion adsorption is simulated using the DFT results. The inclusion of solvation at the electrochemical interface is necessary for accurately predicting the adsorption peak position. The Langmuir model is sufficient for predicting the adsorption peak shape, indicating coverage effects are minor in altering the LSV for acetate and phosphate adsorption. Anion adsorption peak positions are determined for solution phase anion concentrations present in microbial fuel cells and microbial electrolysis cells and discussion is provided as to the impact of anion adsorption on oxygen reduction and hydrogen evolution reaction rates in these devices. © 2011 Elsevier Ltd. All rights reserved.

Frequency comb calibrated frequency-sweeping interferometry for absolute group refractive index measurement of air.

Science.gov (United States)

Yang, Lijun; Wu, Xuejian; Wei, Haoyun; Li, Yan

2017-04-10

The absolute group refractive index of air at 194061.02 GHz is measured in real time using frequency-sweeping interferometry calibrated by an optical frequency comb. The group refractive index of air is calculated from the calibration peaks of the laser frequency variation and the interference signal of the two beams passing through the inner and outer regions of a vacuum cell when the frequency of a tunable external cavity diode laser is scanned. We continuously measure the refractive index of air for 2 h, which shows that the difference between measured results and Ciddor's equation is less than 9.6×10-8, and the standard deviation of that difference is 5.9×10-8. The relative uncertainty of the measured refractive index of air is estimated to be 8.6×10-8. The data update rate is 0.2 Hz, making it applicable under conditions in which air refractive index fluctuates fast.

Gait Transitions of Persons with and without Intellectual Disability

Science.gov (United States)

Agiovlasitis, Stamatis; Yun, Joonkoo; Pavol, Michael J.; McCubbin, Jeffrey A.; Kim, So-Yeun

2008-01-01

This study examined whether the walk-to-run transition speed (W-RTS) and the run-to-walk transition speed (R-WTS) were different or more variable between participants with and without intellectual disability (ID). Nine adults with ID and 10 adults without ID completed in a series of walk-to-run and run-to-walk trials on a treadmill. W-RTS and…

Confirming Variability in the Secondary Eclipse Depth of the Super-Earth 55 Cancri e

Science.gov (United States)

Tamburo, P.; Mandell, A.; Deming, D.; Garhart, E.

2018-05-01

We present a reanalysis of five transit and eight eclipse observations of the ultrashort-period super-Earth 55 Cancri e observed using the Spitzer Space Telescope during 2011–2013. We use pixel-level decorrelation to derive accurate transit and eclipse depths from the Spitzer data, and we perform an extensive error analysis. We focus on determining possible variability in the eclipse data, as was reported in Demory et al. From the transit data, we determine updated orbital parameters, yielding T 0 = 2,455,733.0037 ± 0.0002, P = 0.7365454 ± 0.0000003 days, i = 83.5 ± 1.°3, and R p = 1.89 ± 0.05 R ⊕. Our transit results are consistent with a constant depth, and we conclude that they are not variable. We find a significant amount of variability between the eight eclipse observations and confirm agreement with Demory et al. through a correlation analysis. We convert the eclipse measurements to brightness temperatures, and generate and discuss several heuristic models that explain the evolution of the planet’s eclipse depth versus time. The eclipses are best modeled by a year-to-year variability model, but variability on shorter timescales cannot be ruled out. The derived range of brightness temperatures can be achieved by a dark planet with inefficient heat redistribution intermittently covered over a large fraction of the substellar hemisphere by reflective grains, possibly indicating volcanic activity or cloud variability. This time-variable system should be observable with future space missions, both planned (JWST) and proposed (i.e., ARIEL).

Microgravity Two-Phase Flow Transition

Science.gov (United States)

Parang, M.; Chao, D.

1999-01-01

Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.

Life assessment of PVD based hard coatings by linear sweep voltammetry for high performance industrial application

International Nuclear Information System (INIS)

Malik, M.; Alam, S.; Irfan, M.; Hassan, Z.

2006-01-01

PVD based hard coatings have remarkable achievements in order to improve Tribological and surface properties of coating tools and dies. As PVD based hard coatings have a wide range of industrial applications especially in aerospace and automobile parts where they met different chemical attacks and in order to improve industrial performance these coatings must provide an excellent resistance against corrosion, high temperature oxidation and chemical reaction. This paper focuses on study of behaviour of PVD based hard coatings under different corrosive environments like as H/sub 2/SO/sub 4/, HCl, NaCl, KCl, NaOH etc. Corrosion rate was calculate under linear sweep voltammetry method where the Tafel extrapolation curves used for continuously monitoring the corrosion rate. The results show that these coatings have an excellent resistance against chemical attack. (author)

Mid-infrared Variability of Changing-look AGNs

International Nuclear Information System (INIS)

Sheng, Zhenfeng; Wang, Tinggui; Jiang, Ning; Yang, Chenwei; Peng, Bo; Yan, Lin; Dou, Liming

2017-01-01

It is known that some active galactic nuclei (AGNs) transit from Type 1 to Type 2 or vice versa. There are two explanations for the so-called changing-look AGNs: one is the dramatic change of the obscuration along the line of sight, and the other is the variation of accretion rate. In this Letter, we report the detection of large amplitude variations in the mid-infrared luminosity during the transitions in 10 changing-look AGNs using the Wide-field Infrared Survey Explorer ( WISE ) and newly released Near-Earth Object WISE Reactivation data. The mid-infrared light curves of 10 objects echo the variability in the optical band with a time lag expected for dust reprocessing. The large variability amplitude is inconsistent with the scenario of varying obscuration, rather it supports the scheme of dramatic change in the accretion rate.

Mid-infrared Variability of Changing-look AGNs

Energy Technology Data Exchange (ETDEWEB)

Sheng, Zhenfeng; Wang, Tinggui; Jiang, Ning; Yang, Chenwei; Peng, Bo [CAS Key Laboratory for Researches in Galaxies and Cosmology, University of Sciences and Technology of China, Hefei, Anhui 230026 (China); Yan, Lin [Caltech Optical Observatories, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Dou, Liming, E-mail: shengzf@mail.ustc.edu.cn, E-mail: twang@ustc.edu.cn [Center for Astrophysics, Guangzhou University, Guangzhou 510006 (China)

2017-09-01

It is known that some active galactic nuclei (AGNs) transit from Type 1 to Type 2 or vice versa. There are two explanations for the so-called changing-look AGNs: one is the dramatic change of the obscuration along the line of sight, and the other is the variation of accretion rate. In this Letter, we report the detection of large amplitude variations in the mid-infrared luminosity during the transitions in 10 changing-look AGNs using the Wide-field Infrared Survey Explorer ( WISE ) and newly released Near-Earth Object WISE Reactivation data. The mid-infrared light curves of 10 objects echo the variability in the optical band with a time lag expected for dust reprocessing. The large variability amplitude is inconsistent with the scenario of varying obscuration, rather it supports the scheme of dramatic change in the accretion rate.

Exact extreme-value statistics at mixed-order transitions.

Science.gov (United States)

Bar, Amir; Majumdar, Satya N; Schehr, Grégory; Mukamel, David

2016-05-01

We study extreme-value statistics for spatially extended models exhibiting mixed-order phase transitions (MOT). These are phase transitions that exhibit features common to both first-order (discontinuity of the order parameter) and second-order (diverging correlation length) transitions. We consider here the truncated inverse distance squared Ising model, which is a prototypical model exhibiting MOT, and study analytically the extreme-value statistics of the domain lengths The lengths of the domains are identically distributed random variables except for the global constraint that their sum equals the total system size L. In addition, the number of such domains is also a fluctuating variable, and not fixed. In the paramagnetic phase, we show that the distribution of the largest domain length l_{max} converges, in the large L limit, to a Gumbel distribution. However, at the critical point (for a certain range of parameters) and in the ferromagnetic phase, we show that the fluctuations of l_{max} are governed by novel distributions, which we compute exactly. Our main analytical results are verified by numerical simulations.

A Decidable Recursive Logic for Weighted Transition Systems

DEFF Research Database (Denmark)

Xue, Bingtian; Larsen, Kim Guldstrand; Mardare, Radu Iulian

2014-01-01

In this paper we develop and study the Recursive Weighted Logic (RWL), a multi-modal logic that expresses qualitative and quantitative properties of labelled weighted transition systems (LWSs). LWSs are transition systems labelled with actions and real-valued quantities representing the costs of ...... extends previous results that we have demonstrated for a similar but much more restrictive logic that can only use one variable for each type of resource to encode logical properties....

Numerical investigation of collector cooling for a 1 MW ITER gyrotron operated with vertical sweeping

Energy Technology Data Exchange (ETDEWEB)

Savoldi, Laura; Bertani, Cristina [Dipartimento Energia, Politecnico di Torino (Italy); Cau, Francesca; Cismondi, Fabio [Fusion for Energy, Barcelona (Spain); Gantenbein, Gerd; Illy, Stefan [KIT, Karlsruhe (Germany); Monni, Grazia [Dipartimento Energia, Politecnico di Torino (Italy); Zanino, Roberto, E-mail: roberto.zanino@polito.it [Dipartimento Energia, Politecnico di Torino (Italy)

2015-11-15

The present gyrotron designs for EC plasma heating in nuclear fusion reactors require the safe exhaust of a power comparable to that injected into the plasma, in order to keep the maximum temperature below the acceptable value of 300 °C. In this paper, the commercial computational fluid dynamics (CFD) software STAR-CCM+{sup ®} is used to analyze the thermal performance of the annular copper collector of a 1 MW ITER gyrotron, equipped with a hypervapotron structure made of annular fins with rectangular cavities of aspect ratio (depth/width) = 3, cooled by highly subcooled (90–100 °C) pressurized water flowing at ∼4 m/s. It is assumed that the simple vertical sweeping strategy is used to reduce the very high peak heat flux on the collector (up to 30 MW/m{sup 2} transient, 5 MW/m{sup 2} time average), due to the spent electron beam. The 2D steady-state conjugate heat transfer problem is solved assuming azimuthal symmetry and accounting for 2-phase flow. The single-cavity flow and heat transfer problem is considered first, to optimize the mesh and the selection of the turbulence model. For the operating conditions considered in this paper, the full collector (100+ cavities) solution shows that boiling occurs only in a limited number of cavities close to the peaks of the heat flux, with the vapor remaining trapped in the bottom of the cavities, i.e. no full hypervapotron regime should be achieved in these operating conditions. The steady-state analysis allows the numerical evaluation of the heat transfer coefficients between Cu and water; these are then used as input for the simplified, purely thermal (solid only) analysis of the actual transient problem for the full collector. The results of the simplified model, which allows a huge reduction of the computational effort, are successfully benchmarked against those of a comprehensive thermal–hydraulic simulation. The computed peak Cu temperature is below the acceptable limit under the steady-state (time averaged

A sweep plate emittance scanner for high-power CW ion beams

International Nuclear Information System (INIS)

Debiak, T.W.; Ng, Y.; Sredniawski, J.; Stasi, W.

1996-01-01

Sweep plate scanners are preferred for emittance measurement due to their versatility, simplicity, and precision. At the Advanced Technology and Development Center of Northrop Grumman, we have routinely used these devices for characterization of injector beams with less than 20 W/cm 2 average power density. To characterize higher power beams, like those required for production of tritium or for radioactive waste transmutation, the scanner pod and data collection algorithm must be redesigned due to the possibility of melting the scanner's protective front face or distorting the precision entrance knife edges. Among the methods we have used to mitigate these effects, one consists of drastically reducing the amount of time required for data collection. In this method, the emittance scanner pod traverses the beam in two passes, each requiring less than 0.5 second. In the first pass, the phase space limits of the beam are determined. In the second pass, data is collected primarily within the phase space region limits determined in the first pass. In this way, enough points are collected to assure that the precision of the measurement is high, even though the data collection time for each scan is less than 0.5 second. This paper will describe the layout of the scanner components, the data collection electronics and algorithm, and the data analysis. (author)

Damage spreading for one-dimensional, non-equilibrium models with parity conserving phase transitions

CERN Document Server

Ódor, G; Odor, Geza; Menyhard, Nora

1998-01-01

The damage spreading (DS) transitions of two one-dimensional stochastic cellular automata suggested by Grassberger (A and B) and the kinetic Ising model of Menyhárd (NEKIM) have been investigated on the level of kinks and spins. On the level of spins the parity conservation is not satisfied and therefore studying these models provides a convenient tool to understand the dependence of DS properties on symmetries. For the model B the critical point and the DS transition point is well separated and directed percolation damage spreading transition universality was found for spin damage as well as for kink damage in spite of the conservation of damage variables modulo 2 in the latter case. For the A stochastic cellular automaton, and the NEKIM model the two transition points coincide with drastic effects on the damage of spin and kink variables showing different time dependent behaviours. While the kink DS transition is continuous and shows regular PC class universality, the spin damage exhibits a discontinuous p...

Sweep efficiency improvement of waterfloods in Steelman Units V and VII through the application of computer models

Energy Technology Data Exchange (ETDEWEB)

Woods, W S

1967-01-01

The use of a digital computer program as a tool to investigate the position of flood fronts in 2 Steelman units is described. The program involves a simulated potentiometric analyzer. Several years of historical performance were utilized and alterations to the model were made to match the historical performance until a satisfactory prediction is obtained. Subsequent to matching the historical performance, future predictions were obtained to evaluate the efficiency of the ultimate sweep configuration in the reservoir. These data are used as directives for improving the operation of the waterfloods. Rather than the complicated and elaborate computer techniques currently in use, it is suggested that the results obtained in this particular application of simple techniques provide sufficient economic operating directives.

Emerging adulthood features and criteria for adulthood : Variable- and person-centered approaches

NARCIS (Netherlands)

Tagliabue, Semira; Crocetti, Elisabetta; Lanz, Margherita

Reaching adulthood is the aim of the transition to adulthood; however, emerging adults differently define both adulthood and the transitional period they are living. Variable-centered and person-centered approaches were integrated in the present paper to investigate if the criteria used to define

Fast grid layout algorithm for biological networks with sweep calculation.

Science.gov (United States)

Kojima, Kaname; Nagasaki, Masao; Miyano, Satoru

2008-06-15

Properly drawn biological networks are of great help in the comprehension of their characteristics. The quality of the layouts for retrieved biological networks is critical for pathway databases. However, since it is unrealistic to manually draw biological networks for every retrieval, automatic drawing algorithms are essential. Grid layout algorithms handle various biological properties such as aligning vertices having the same attributes and complicated positional constraints according to their subcellular localizations; thus, they succeed in providing biologically comprehensible layouts. However, existing grid layout algorithms are not suitable for real-time drawing, which is one of requisites for applications to pathway databases, due to their high-computational cost. In addition, they do not consider edge directions and their resulting layouts lack traceability for biochemical reactions and gene regulations, which are the most important features in biological networks. We devise a new calculation method termed sweep calculation and reduce the time complexity of the current grid layout algorithms through its encoding and decoding processes. We conduct practical experiments by using 95 pathway models of various sizes from TRANSPATH and show that our new grid layout algorithm is much faster than existing grid layout algorithms. For the cost function, we introduce a new component that penalizes undesirable edge directions to avoid the lack of traceability in pathways due to the differences in direction between in-edges and out-edges of each vertex. Java implementations of our layout algorithms are available in Cell Illustrator. masao@ims.u-tokyo.ac.jp Supplementary data are available at Bioinformatics online.

Identification of X-linked quantitative trait loci affecting cold tolerance in Drosophila melanogaster and fine mapping by selective sweep analysis.

Science.gov (United States)

Svetec, Nicolas; Werzner, Annegret; Wilches, Ricardo; Pavlidis, Pavlos; Alvarez-Castro, José M; Broman, Karl W; Metzler, Dirk; Stephan, Wolfgang

2011-02-01

Drosophila melanogaster is a cosmopolitan species that colonizes a great variety of environments. One trait that shows abundant evidence for naturally segregating genetic variance in different populations of D. melanogaster is cold tolerance. Previous work has found quantitative trait loci (QTL) exclusively on the second and the third chromosomes. To gain insight into the genetic architecture of cold tolerance on the X chromosome and to compare the results with our analyses of selective sweeps, a mapping population was derived from a cross between substitution lines that solely differed in the origin of their X chromosome: one originates from a European inbred line and the other one from an African inbred line. We found a total of six QTL for cold tolerance factors on the X chromosome of D. melanogaster. Although the composite interval mapping revealed slightly different QTL profiles between sexes, a coherent model suggests that most QTL overlapped between sexes, and each explained around 5-14% of the genetic variance (which may be slightly overestimated). The allelic effects were largely additive, but we also detected two significant interactions. Taken together, this provides evidence for multiple QTL that are spread along the entire X chromosome and whose effects range from low to intermediate. One detected transgressive QTL influences cold tolerance in different ways for the two sexes. While females benefit from the European allele increasing their cold tolerance, males tend to do better with the African allele. Finally, using selective sweep mapping, the candidate gene CG16700 for cold tolerance colocalizing with a QTL was identified. © 2010 Blackwell Publishing Ltd.

Discovering transits of HD 209458-b type planets with Hipparcos and FAME photometry

Science.gov (United States)

Castellano, Timothy Paul

The motivation and prospects for success of a search for transits of short-period extrasolar planets of late-type main sequence stars in the Hipparcos satellite photometry archive is outlined. Recent extrasolar planet discoveries by the radial velocity (RV) method reveal that 1 in 20 spectral type F, G and K dwarfs possess short-period planets. Careful consideration of the transit detection probability as a function of stellar spectral type and planet orbit size results in the expectation that 6 to 24 transiting planets may be found among the 118,204 Hipparcos catalog stars. A search algorithm based on the known properties of the single known transiting extrasolar planet HD 209458-b was applied to carefully- selected samples of stars. The results of these searches and simulations of the detection efficiency for idealized transits are presented. Statistical and catalog-based methods for discriminating transits from intrinsic stellar variability and eclipses due to stellar companions are developed and described. Candidate lists that are the results of these searches are presented. Each candidate is placed in a color magnitude diagram based on Hipparcos derived distances and absolute magnitudes in order to clearly identify evolved stars. The effect of Lutz-Kelker bias on this main sequence membership determination is discussed in an Appendix. A Hipparcos-photometry-based intrinsic stellar variability determination is performed and compared to ground-based measurements. It is shown that intrinsic stellar variability of late-type main sequence stars is not a major concern for extrasolar jovian planet transit searches. The prospects for transit detection by the higher precision measurements of several hundred thousand main sequence stars to be made by the upcoming Full Sky Astrometric Explorer (FAME) satellite are similarly explored. A novel method for directly determining the mass of a transiting planet's parent star from timing measurements is introduced briefly in an

Transverse susceptibility as a probe of the magnetocrystalline anisotropy-driven phase transition in Pr0.5Sr0.5CoO3

Science.gov (United States)

Frey Huls, N. A.; Bingham, N. S.; Phan, M. H.; Srikanth, H.; Stauffer, D. D.; Leighton, C.

2011-01-01

Half-doped Pr1-xSrxCoO3 (x=0.5) displays anomalous magnetism, most notably manifest in the field-cooled magnetization versus temperature curves under different applied cooling fields. Recently, an explanation was advanced that a magnetocrystalline anisotropy transition driven by a structural transition at 120 K is the origin of this behavior. In this paper, we further elucidate the nature of the magnetic anisotropy across the low-temperature phase transition in this material by means of transverse susceptibility (TS) measurements performed using a self-resonant tunnel diode oscillator. TS probes magnetic materials by means of a small radio frequency oriented transverse to a dc field that sweeps from positive to negative saturation. TS scans as a function of field clearly reveal peaks associated with the anisotropy (HK) and switching fields (HS). When peak position is examined as a function of temperature, ˜120 K the signature of a ferromagnetic-to-ferromagnetic phase transition is evident as a sharp feature in HK and a corresponding cusp in HS. A third TS peak (not previously observed in other classes of magnetic oxides such as manganites and spinel ferrites) is found to be correlated with the crossover field (Hcr) in the unconventional magnetization versus temperature [M(T)] behavior. We observe a strong temperature dependence of Hcr at ˜120 K using this technique, which suggests the magnetic-field-influenced magnetocrystalline anisotropy transition. We show the switching between the high-field magnetization state and the low-field magnetization state associated with the magnetocrystalline anisotropy transition is irreversible when the magnetic field is recycled. Finally, we demonstrate that the TS peak magnitude indicates easy axis switching associated with this phase transition, even in these polycrystalline samples. Our results further confirm that TS provides new insights into the magnetic behavior of complex oxides.

The Bursting Pulsar GRO J1744-28: the Slowest Transitional Pulsar?

Science.gov (United States)

Court, J. M. C.; Altamirano, D.; Sanna, A.

2018-04-01

GRO J1744-28 (the Bursting Pulsar) is a neutron star LMXB which shows highly structured X-ray variability near the end of its X-ray outbursts. In this letter we show that this variability is analogous to that seen in Transitional Millisecond Pulsars such as PSR J1023+0038: `missing link' systems consisting of a pulsar nearing the end of its recycling phase. As such, we show that the Bursting Pulsar may also be associated with this class of objects. We discuss the implications of this scenario; in particular, we discuss the fact that the Bursting Pulsar has a significantly higher spin period and magnetic field than any other known Transitional Pulsar. If the Bursting Pulsar is indeed transitional, then this source opens a new window of oppurtunity to test our understanding of these systems in an entirely unexplored physical regime.

Predictive Accuracy of Sweep Frequency Impedance Technology in Identifying Conductive Conditions in Newborns.

Science.gov (United States)

Aithal, Venkatesh; Kei, Joseph; Driscoll, Carlie; Murakoshi, Michio; Wada, Hiroshi

2018-02-01

Diagnosing conductive conditions in newborns is challenging for both audiologists and otolaryngologists. Although high-frequency tympanometry (HFT), acoustic stapedial reflex tests, and wideband absorbance measures are useful diagnostic tools, there is performance measure variability in their detection of middle ear conditions. Additional diagnostic sensitivity and specificity measures gained through new technology such as sweep frequency impedance (SFI) measures may assist in the diagnosis of middle ear dysfunction in newborns. The purpose of this study was to determine the test performance of SFI to predict the status of the outer and middle ear in newborns against commonly used reference standards. Automated auditory brainstem response (AABR), HFT (1000 Hz), transient evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and SFI tests were administered to the study sample. A total of 188 neonates (98 males and 90 females) with a mean gestational age of 39.4 weeks were included in the sample. Mean age at the time of testing was 44.4 hr. Diagnostic accuracy of SFI was assessed in terms of its ability to identify conductive conditions in neonates when compared with nine different reference standards (including four single tests [AABR, HFT, TEOAE, and DPOAE] and five test batteries [HFT + DPOAE, HFT + TEOAE, DPOAE + TEOAE, DPOAE + AABR, and TEOAE + AABR]), using receiver operating characteristic (ROC) analysis and traditional test performance measures such as sensitivity and specificity. The test performance of SFI against the test battery reference standard of HFT + DPOAE and single reference standard of HFT was high with an area under the ROC curve (AROC) of 0.87 and 0.82, respectively. Although the HFT + DPOAE test battery reference standard performed better than the HFT reference standard in predicting middle ear conductive conditions in neonates, the difference in AROC was not significant. Further analysis revealed that the

Problem of phase transitions in nuclear structure

International Nuclear Information System (INIS)

Scharff-Goldhaber, G.

1980-01-01

Phase transitions between rotational and vibrational nuclei are discussed from the point of view of the variable moment of inertia model. A three-dimensional plot of the ground-state moments of inertia of even-even nuclei vs N and Z is shown. 3 figures

A Wind Tunnel Investigation of Joined Wing Scissor Morphing

Science.gov (United States)

2006-06-01

would use the low sweep for carrier landing and subsonic cruise, and use the high sweep for 12 supersonic flight [13]. According to Raymer [19...Wright-Patterson AFB, Ohio: Air Force Institute of Technology, 2005. 12. Katz, Joseph, Shaun Byrne, and Robert Hahl. "Stall Resistance Features of...Lifting-Body Airplane Configurations." Journal of Aircraft 2nd ser. 36 (1999): 471-474. 13. Kress, Robert W. "Variable Sweep Wing Design." AIAA 83

The Impact of the Transition to HE: Emotions, Feelings and Sensations

Science.gov (United States)

Dias, Diana; Sá, Maria José

2014-01-01

Transition to Higher Education (HE) is a significant life event and it is supposed to be a very agreeable experience to students. However, such impact is not linear, being mediated by students' psychosocial variables and by their own perceptions concerning the HE environment. Transition to HE encompasses many tasks to cope with changes:…

Determining Plane-Sweep Sampling Points in Image Space Using the Cross-Ratio for Image-Based Depth Estimation

Science.gov (United States)

Ruf, B.; Erdnuess, B.; Weinmann, M.

2017-08-01

With the emergence of small consumer Unmanned Aerial Vehicles (UAVs), the importance and interest of image-based depth estimation and model generation from aerial images has greatly increased in the photogrammetric society. In our work, we focus on algorithms that allow an online image-based dense depth estimation from video sequences, which enables the direct and live structural analysis of the depicted scene. Therefore, we use a multi-view plane-sweep algorithm with a semi-global matching (SGM) optimization which is parallelized for general purpose computation on a GPU (GPGPU), reaching sufficient performance to keep up with the key-frames of input sequences. One important aspect to reach good performance is the way to sample the scene space, creating plane hypotheses. A small step size between consecutive planes, which is needed to reconstruct details in the near vicinity of the camera may lead to ambiguities in distant regions, due to the perspective projection of the camera. Furthermore, an equidistant sampling with a small step size produces a large number of plane hypotheses, leading to high computational effort. To overcome these problems, we present a novel methodology to directly determine the sampling points of plane-sweep algorithms in image space. The use of the perspective invariant cross-ratio allows us to derive the location of the sampling planes directly from the image data. With this, we efficiently sample the scene space, achieving higher sampling density in areas which are close to the camera and a lower density in distant regions. We evaluate our approach on a synthetic benchmark dataset for quantitative evaluation and on a real-image dataset consisting of aerial imagery. The experiments reveal that an inverse sampling achieves equal and better results than a linear sampling, with less sampling points and thus less runtime. Our algorithm allows an online computation of depth maps for subsequences of five frames, provided that the relative

DETERMINING PLANE-SWEEP SAMPLING POINTS IN IMAGE SPACE USING THE CROSS-RATIO FOR IMAGE-BASED DEPTH ESTIMATION

Directory of Open Access Journals (Sweden)

B. Ruf

2017-08-01

Full Text Available With the emergence of small consumer Unmanned Aerial Vehicles (UAVs, the importance and interest of image-based depth estimation and model generation from aerial images has greatly increased in the photogrammetric society. In our work, we focus on algorithms that allow an online image-based dense depth estimation from video sequences, which enables the direct and live structural analysis of the depicted scene. Therefore, we use a multi-view plane-sweep algorithm with a semi-global matching (SGM optimization which is parallelized for general purpose computation on a GPU (GPGPU, reaching sufficient performance to keep up with the key-frames of input sequences. One important aspect to reach good performance is the way to sample the scene space, creating plane hypotheses. A small step size between consecutive planes, which is needed to reconstruct details in the near vicinity of the camera may lead to ambiguities in distant regions, due to the perspective projection of the camera. Furthermore, an equidistant sampling with a small step size produces a large number of plane hypotheses, leading to high computational effort. To overcome these problems, we present a novel methodology to directly determine the sampling points of plane-sweep algorithms in image space. The use of the perspective invariant cross-ratio allows us to derive the location of the sampling planes directly from the image data. With this, we efficiently sample the scene space, achieving higher sampling density in areas which are close to the camera and a lower density in distant regions. We evaluate our approach on a synthetic benchmark dataset for quantitative evaluation and on a real-image dataset consisting of aerial imagery. The experiments reveal that an inverse sampling achieves equal and better results than a linear sampling, with less sampling points and thus less runtime. Our algorithm allows an online computation of depth maps for subsequences of five frames, provided that

SPECTRAL VARIABILITY FROM THE PATCHY ATMOSPHERES OF T AND Y DWARFS

International Nuclear Information System (INIS)

Morley, Caroline V.; Fortney, Jonathan J.; Marley, Mark S.; Lupu, Roxana

2014-01-01

Brown dwarfs of a variety of spectral types have been observed to be photometrically variable. Previous studies have focused on objects at the L/T transition, where the iron and silicate clouds in L dwarfs break up or dissipate. However, objects outside of this transitional effective temperature regime also exhibit variability. Here, we present models for mid-late T dwarfs and Y dwarfs. We present models that include patchy salt and sulfide clouds as well as water clouds for the Y dwarfs. We find that for objects over 375 K, patchy cloud opacity would generate the largest amplitude variability within near-infrared spectral windows. For objects under 375 K, water clouds also become important and generate larger amplitude variability in the mid-infrared. We also present models in which we perturb the temperature structure at different pressure levels of the atmosphere to simulate hot spots. These models show the most variability in the absorption features between spectral windows. The variability is strongest at wavelengths that probe pressure levels at which the heating is the strongest. The most illustrative types of observations for understanding the physical processes underlying brown dwarf variability are simultaneous, multi-wavelength observations that probe both inside and outside of molecular absorption features

Assessment of transition readiness in adolescents and young adults with chronic health conditions.

Science.gov (United States)

Jensen, Paul T; Paul, Gabrielle V; LaCount, Stephanie; Peng, Juan; Spencer, Charles H; Higgins, Gloria C; Boyle, Brendan; Kamboj, Manmohan; Smallwood, Christopher; Ardoin, Stacy P

2017-09-09

Transition from pediatric to adult health care is a vulnerable period for adolescents and young adults. Challenges include paucity of validated measures to assess patients' transition readiness. We evaluated the Transition Readiness Assessment Questionnaire (TRAQ) in adolescents and young adults with rheumatic, gastrointestinal, and endocrine disorders. We examined whether baseline TRAQ scores and other demographic variables predicted transition to adult care over a three year follow up period. In this descriptive study at a single institution, eighty-nine adolescents at a single pediatric academic medical center completed demographic and medical history surveys and the TRAQ and were followed over 3 years by telephone interview to determine whether they had transitioned to adult subspecialty care. Transition was defined as attending at least one adult subspecialty appointment. Multivariable logistic regression and Cox proportional hazards regression models were used to determine whether TRAQ scores predicted time to transition. Of the participants, 56% had rheumatic, 21% endocrine, and 23% gastrointestinal conditions. The TRAQ self-management domain score was not significantly associated with age, gender, socioeconomic status, or specialty. The TRAQ self-advocacy score increased with age. Baseline TRAQ scores did not predict transition or time to transition over three years. In this cohort of adolescents and young adults who were 16 to 23 years of age at enrollment, 48% transitioned to adult care over three years of follow up. Nearly half reported not discussing transition with provider or seeing provider independently for part of visit. Older age but not other demographic variables nor baseline TRAQ score predicted transition or time to transition to an adult subspecialty provider; however, a there was a trend towards shorter time to transition with the highest quartile TRAQ scores.

Dimensional transition of the universe

International Nuclear Information System (INIS)

Terazawa, Hidezumi.

1989-08-01

In the extended n-dimensional Einstein theory of gravitation, where the spacetime dimension can be taken as a 'dynamical variable' which is determined by the 'Hamilton principle' of minimizing the extended Einstein-Hilbert action, it is suggested that our Universe of four-dimensional spacetime may encounter an astonishing dimensional transition into a new universe of three-dimensional or higher-than-four-dimensional spacetime. (author)

Transition radiation and transition scattering

International Nuclear Information System (INIS)

Ginzburg, V.L.

1982-01-01

Transition radiation is a process of a rather general character. It occurs when some source, which does not have a proper frequency (for example, a charge) moves at a constant velocity in an inhomogeneous and (or) nonstationary medium or near such a medium. The simplest type of transition radiation takes place when a charge crosses a boundary between two media (the role of one of the media may be played by vacuum). In the case of periodic variation of the medium, transition radiation possesses some specific features (resonance transition radiation or transition scattering). Transition scattering occurs, in particular, when a permittivity wave falls onto an nonmoving (fixed) charge. Transition scattering is closely connected with transition bremsstrahlung radiation. All these transition processes are essential for plasma physics. Transition radiation and transition scattering have analogues outside the framework of electrodynamics (like in the case of Vavilov-Cherenkov radiation). In the present report the corresponding range of phenomena is elucidated, as far as possible, in a generally physical aspect. (Auth.)

Searching for I-band variability in stars in the M/L spectral transition region

Science.gov (United States)

Ramsay, Gavin; Hakala, Pasi; Doyle, J. Gerry

2015-10-01

We report on I-band photometric observations of 21 stars with spectral types between M8 and L4 made using the Isaac Newton Telescope. The total amount of time for observations which had a cadence of test for photometric variability using the Kruskal-Wallis H-test and find that four sources (2MASS J10224821+5825453, 2MASS J07464256+2000321, 2MASS J16262034+3925190 and 2MASS J12464678+4027150) were found to be significantly variable at least on one epoch. Three of these sources are reported as photometrically variable for the first time. If we include sources which were deemed marginally variable, the number of variable sources is 6 (29 per cent). No flares were detected from any source. The percentage of sources which we found were variable is similar to previous studies. We summarize the mechanisms which have been put forward to explain the light curves of brown dwarfs.

LASR-Guided Variability Subtraction: The Linear Algorithm for Significance Reduction of Stellar Seismic Activity

Science.gov (United States)

Horvath, Sarah; Myers, Sam; Ahlers, Johnathon; Barnes, Jason W.

2017-10-01

Stellar seismic activity produces variations in brightness that introduce oscillations into transit light curves, which can create challenges for traditional fitting models. These oscillations disrupt baseline stellar flux values and potentially mask transits. We develop a model that removes these oscillations from transit light curves by minimizing the significance of each oscillation in frequency space. By removing stellar variability, we prepare each light curve for traditional fitting techniques. We apply our model to $\\delta$-Scuti KOI-976 and demonstrate that our variability subtraction routine successfully allows for measuring bulk system characteristics using traditional light curve fitting. These results open a new window for characterizing bulk system parameters of planets orbiting seismically active stars.

Towards predictive models for transitionally rough surfaces

Science.gov (United States)

Abderrahaman-Elena, Nabil; Garcia-Mayoral, Ricardo

2017-11-01

We analyze and model the previously presented decomposition for flow variables in DNS of turbulence over transitionally rough surfaces. The flow is decomposed into two contributions: one produced by the overlying turbulence, which has no footprint of the surface texture, and one induced by the roughness, which is essentially the time-averaged flow around the surface obstacles, but modulated in amplitude by the first component. The roughness-induced component closely resembles the laminar steady flow around the roughness elements at the same non-dimensional roughness size. For small - yet transitionally rough - textures, the roughness-free component is essentially the same as over a smooth wall. Based on these findings, we propose predictive models for the onset of the transitionally rough regime. Project supported by the Engineering and Physical Sciences Research Council (EPSRC).

The Physics of Structural Phase Transitions

CERN Document Server

Fujimoto, Minoru

2005-01-01

Phase transitions in which crystalline solids undergo structural changes present an interesting problem in the interplay between the crystal structure and the ordering process that is typically nonlinear. Intended for readers with prior knowledge of basic condensed-matter physics, this book emphasizes the physics behind spontaneous structural changes in crystals. Starting with the relevant thermodynamic principles, the text discusses the nature of order variables in collective motion in structural phase transitions, where a singularity in such a collective mode is responsible for lattice instability as revealed by soft phonons. In this book, critical anomalies at second-order structural transitions are first analyzed with the condensate model. Discussions on the nonlinear ordering mechanism are followed with the soliton theory, thereby interpreting the role of long-range order. Relevant details for nonlinear mathematics are therefore given for minimum necessity. The text also discusses experimental methods fo...

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

Energy Technology Data Exchange (ETDEWEB)

James, Revis [Electric Power Research Institute, Palo Alto, CA (United States); Hesler, Stephen [Electric Power Research Institute, Palo Alto, CA (United States); Bistline, John [Electric Power Research Institute, Palo Alto, CA (United States)

2015-03-31

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

Response to work transitions by United States Army personnel: effects of self-esteem, self-efficacy, and career resilience.

Science.gov (United States)

Gowan, M A; Craft, S L; Zimmermann, R A

2000-06-01

This paper examined association of self-esteem, self-efficacy, and career resilience with the responses of 171 United States Army personnel making the transition to civilian jobs. Specifically, the study addresses whether personality traits are related to the appraisal of the transition from Army to civilian life and to how individuals plan to manage the transition to yield employment success. Self-esteem, self-efficacy, and career resilience were the personality variables examined. Only self-esteem and career resilience were related to harm appraisals of the transition. None of the personality variables were related to use of coping strategies. Limitations of the study and suggestions for research are provided.

The yule approximation for the site frequency spectrum after a selective sweep.

Directory of Open Access Journals (Sweden)

Sebastian Bossert

Full Text Available In the area of evolutionary theory, a key question is which portions of the genome of a species are targets of natural selection. Genetic hitchhiking is a theoretical concept that has helped to identify various such targets in natural populations. In the presence of recombination, a severe reduction in sequence diversity is expected around a strongly beneficial allele. The site frequency spectrum is an important tool in genome scans for selection and is composed of the numbers S(1,...,S(n-1, where S(k is the number of single nucleotide polymorphisms (SNPs present in k from n individuals. Previous work has shown that both the number of low- and high-frequency variants are elevated relative to neutral evolution when a strongly beneficial allele fixes. Here, we follow a recent investigation of genetic hitchhiking using a marked Yule process to obtain an analytical prediction of the site frequency spectrum in a panmictic population at the time of fixation of a highly beneficial mutation. We combine standard results from the neutral case with the effects of a selective sweep. As simulations show, the resulting formula produces predictions that are more accurate than previous approaches for the whole frequency spectrum. In particular, the formula correctly predicts the elevation of low- and high-frequency variants and is significantly more accurate than previously derived formulas for intermediate frequency variants.

Moving Difference (MDIFF) Non-adiabatic rapid sweep (NARS) EPR of copper(II)

Science.gov (United States)

Hyde, James S.; Bennett, Brian; Kittell, Aaron W.; Kowalski, Jason M.; Sidabras, Jason W.

2014-01-01

Non Adiabatic Rapid Sweep (NARS) EPR spectroscopy has been introduced for application to nitroxide-labeled biological samples (AW Kittell et al, (2011)). Displays are pure absorption, and are built up by acquiring data in spectral segments that are concatenated. In this paper we extend the method to frozen solutions of copper-imidazole, a square planar copper complex with four in-plane nitrogen ligands. Pure absorption spectra are created from concatenation of 170 5-gauss segments spanning 850 G at 1.9 GHz. These spectra, however, are not directly useful since nitrogen superhyperfine couplings are barely visible. Application of the moving difference (MDIFF) algorithm to the digitized NARS pure absorption spectrum is used to produce spectra that are analogous to the first harmonic EPR. The signal intensity is about 4 times higher than when using conventional 100 kHz field modulation, depending on line shape. MDIFF not only filters the spectrum, but also the noise, resulting in further improvement of the SNR for the same signal acquisition time. The MDIFF amplitude can be optimized retrospectively, different spectral regions can be examined at different amplitudes, and an amplitude can be used that is substantially greater than the upper limit of the field modulation amplitude of a conventional EPR spectrometer, which improves the signal-to-noise ratio of broad lines. PMID:24036469

Monozygotic twins discordant for common variable immunodeficiency reveal impaired DNA demethylation during naïve-to-memory B-cell transition

Science.gov (United States)

Rodríguez-Cortez, Virginia C.; del Pino-Molina, Lucia; Rodríguez-Ubreva, Javier; Ciudad, Laura; Gómez-Cabrero, David; Company, Carlos; Urquiza, José M.; Tegnér, Jesper; Rodríguez-Gallego, Carlos; López-Granados, Eduardo; Ballestar, Esteban

2015-01-01

Common variable immunodeficiency (CVID), the most frequent primary immunodeficiency characterized by loss of B-cell function, depends partly on genetic defects, and epigenetic changes are thought to contribute to its aetiology. Here we perform a high-throughput DNA methylation analysis of this disorder using a pair of CVID-discordant MZ twins and show predominant gain of DNA methylation in CVID B cells with respect to those from the healthy sibling in critical B lymphocyte genes, such as PIK3CD, BCL2L1, RPS6KB2, TCF3 and KCNN4. Individual analysis confirms hypermethylation of these genes. Analysis in naive, unswitched and switched memory B cells in a CVID patient cohort shows impaired ability to demethylate and upregulate these genes in transitioning from naive to memory cells in CVID. Our results not only indicate a role for epigenetic alterations in CVID but also identify relevant DNA methylation changes in B cells that could explain the clinical manifestations of CVID individuals. PMID:26081581

Rural Adolescents' Reading Motivation, Achievement and Behavior across Transition to High School

Science.gov (United States)

Cantrell, Susan Chambers; Rintamaa, Margaret; Anderman, Eric M.; Anderman, Lynley H.

2018-01-01

The authors examined 1,781 rural students' reading motivation and behavior across the transition from middle to high school. Using expectancy-value theory, they investigated how motivational variables predicted changes in reading behavior and achievement across the transition in terms of their expectancies, values, and out-of-school reading…

An intermittency model for predicting roughness induced transition

Science.gov (United States)

Ge, Xuan; Durbin, Paul

2014-11-01

An extended model for roughness-induced transition is proposed based on an intermittency transport equation for RANS modeling formulated in local variables. To predict roughness effects in the fully turbulent boundary layer, published boundary conditions for k and ω are used, which depend on the equivalent sand grain roughness height, and account for the effective displacement of wall distance origin. Similarly in our approach, wall distance in the transition model for smooth surfaces is modified by an effective origin, which depends on roughness. Flat plate test cases are computed to show that the proposed model is able to predict the transition onset in agreement with a data correlation of transition location versus roughness height, Reynolds number, and inlet turbulence intensity. Experimental data for a turbine cascade are compared with the predicted results to validate the applicability of the proposed model. Supported by NSF Award Number 1228195.

Latent Transition Analysis with a Mixture Item Response Theory Measurement Model

Science.gov (United States)

Cho, Sun-Joo; Cohen, Allan S.; Kim, Seock-Ho; Bottge, Brian

2010-01-01

A latent transition analysis (LTA) model was described with a mixture Rasch model (MRM) as the measurement model. Unlike the LTA, which was developed with a latent class measurement model, the LTA-MRM permits within-class variability on the latent variable, making it more useful for measuring treatment effects within latent classes. A simulation…

Towards Bridging the Gaps in Holistic Transition Prediction via Numerical Simulations

Science.gov (United States)

Choudhari, Meelan M.; Li, Fei; Duan, Lian; Chang, Chau-Lyan; Carpenter, Mark H.; Streett, Craig L.; Malik, Mujeeb R.

2013-01-01

The economic and environmental benefits of laminar flow technology via reduced fuel burn of subsonic and supersonic aircraft cannot be realized without minimizing the uncertainty in drag prediction in general and transition prediction in particular. Transition research under NASA's Aeronautical Sciences Project seeks to develop a validated set of variable fidelity prediction tools with known strengths and limitations, so as to enable "sufficiently" accurate transition prediction and practical transition control for future vehicle concepts. This paper provides a summary of selected research activities targeting the current gaps in high-fidelity transition prediction, specifically those related to the receptivity and laminar breakdown phases of crossflow induced transition in a subsonic swept-wing boundary layer. The results of direct numerical simulations are used to obtain an enhanced understanding of the laminar breakdown region as well as to validate reduced order prediction methods.

Translating glucose variability metrics into the clinic via Continuous Glucose Monitoring: a Graphical User Interface for Diabetes Evaluation (CGM-GUIDE©).

Science.gov (United States)

Rawlings, Renata A; Shi, Hang; Yuan, Lo-Hua; Brehm, William; Pop-Busui, Rodica; Nelson, Patrick W

2011-12-01

Several metrics of glucose variability have been proposed to date, but an integrated approach that provides a complete and consistent assessment of glycemic variation is missing. As a consequence, and because of the tedious coding necessary during quantification, most investigators and clinicians have not yet adopted the use of multiple glucose variability metrics to evaluate glycemic variation. We compiled the most extensively used statistical techniques and glucose variability metrics, with adjustable hyper- and hypoglycemic limits and metric parameters, to create a user-friendly Continuous Glucose Monitoring Graphical User Interface for Diabetes Evaluation (CGM-GUIDE©). In addition, we introduce and demonstrate a novel transition density profile that emphasizes the dynamics of transitions between defined glucose states. Our combined dashboard of numerical statistics and graphical plots support the task of providing an integrated approach to describing glycemic variability. We integrated existing metrics, such as SD, area under the curve, and mean amplitude of glycemic excursion, with novel metrics such as the slopes across critical transitions and the transition density profile to assess the severity and frequency of glucose transitions per day as they move between critical glycemic zones. By presenting the above-mentioned metrics and graphics in a concise aggregate format, CGM-GUIDE provides an easy to use tool to compare quantitative measures of glucose variability. This tool can be used by researchers and clinicians to develop new algorithms of insulin delivery for patients with diabetes and to better explore the link between glucose variability and chronic diabetes complications.

Diffusion-induced periodic transition between oscillatory modes in amplitude-modulated patterns

Energy Technology Data Exchange (ETDEWEB)

Tang, Xiaodong; He, Yuxiu; Wang, Shaorong; Gao, Qingyu, E-mail: gaoqy@cumt.edu.cn [College of Chemical Engineering, China University of Mining and Technology, Xuzhou 221008 (China); Epstein, Irving R., E-mail: epstein@brandeis.edu [Department of Chemistry and Volen Center for Complex Systems, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110 (United States); Wang, Qun [School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116 (China)

2014-06-15

We study amplitude-modulated waves, e.g., wave packets in one dimension, overtarget spirals and superspirals in two dimensions, under mixed-mode oscillatory conditions in a three-variable reaction-diffusion model. New transition zones, not seen in the homogeneous system, are found, in which periodic transitions occur between local 1{sup N−1} and 1{sup N} oscillations. Amplitude-modulated complex patterns result from periodic transition between (N − 1)-armed and N-armed waves. Spatial recurrence rates provide a useful guide to the stability of these modulated patterns.

Program for the calculation of the semiempirical radial wave functions by means of the variable Tomas-Fermi potential and for the determination of the radial integrals of the dipole transitions

International Nuclear Information System (INIS)

Kuzmitskite, L.L.

1980-01-01

The program is meant for the determination of the semiempirical radial wave functions of the positive ions and the calculation of the radial integrals of the dipole transition. The semiempirical wave functions are calculated using Tomas-Fermi potential with the variable parameter, which provides for the coincidence of the energy obtained with the ionization energy of the state under consideration. The program is written in the FORTRAN language for the BESM-6 computer

Thresholds and Smooth Transitions in Vector Autoregressive Models

DEFF Research Database (Denmark)

Hubrich, Kirstin; Teräsvirta, Timo

This survey focuses on two families of nonlinear vector time series models, the family of Vector Threshold Regression models and that of Vector Smooth Transition Regression models. These two model classes contain incomplete models in the sense that strongly exogeneous variables are allowed in the...

Transition to Parenthood and Conjugal Life: Comparisons between Planned and Unplanned Pregnancies

Science.gov (United States)

Bouchard, Genevieve; Boudreau, Jolene; Hebert, Renee

2006-01-01

One of the variables that could explain the considerable variety of ways that adult couples handle the transition to parenthood is whether the pregnancy was planned or not. However, very little is known about the impact of pregnancy intendedness on the conjugal life of couples during this transition. The aim of this study was to address this gap…

Effects of asymmetric nuclear introgression, introgressive mitochondrial sweep, and purifying selection on phylogenetic reconstruction and divergence estimates in the Pacific clade of Locustella warblers.

Science.gov (United States)

Drovetski, Sergei V; Semenov, Georgy; Red'kin, Yaroslav A; Sotnikov, Vladimir N; Fadeev, Igor V; Koblik, Evgeniy A

2015-01-01

When isolated but reproductively compatible populations expand geographically and meet, simulations predict asymmetric introgression of neutral loci from a local to invading taxon. Genetic introgression may affect phylogenetic reconstruction by obscuring topology and divergence estimates. We combined phylogenetic analysis of sequences from one mtDNA and 12 nuDNA loci with analysis of gene flow among 5 species of Pacific Locustella warblers to test for presence of genetic introgression and its effects on tree topology and divergence estimates. Our data showed that nuDNA introgression was substantial and asymmetrical among all members of superspecies groups whereas mtDNA showed no introgression except a single species pair where the invader's mtDNA was swept by mtDNA of the local species. This introgressive sweep of mtDNA had the opposite direction of the nuDNA introgression and resulted in the paraphyly of the local species' mtDNA haplotypes with respect to those of the invader. Тhe multilocus nuDNA species tree resolved all inter- and intraspecific relationships despite substantial introgression. However, the node ages on the species tree may be underestimated as suggested by the differences in node age estimates based on non-introgressing mtDNA and introgressing nuDNA. In turn, the introgressive sweep and strong purifying selection appear to elongate internal branches in the mtDNA gene tree.

Electrochemical Modeling and Performance of a Lithium- and Manganese-Rich Layered Transition-Metal Oxide Positive Electrode

Energy Technology Data Exchange (ETDEWEB)

Dees, Dennis W.; Abraham, Daniel P; Lu, Wenquan; Gallagher, Kevin G.; Bettge, Martin; Jansen, Andrew N

2015-01-21

The impedance of a lithium- and manganese-rich layered transition-metal oxide (MR-NMC) positive electrode, specifically Li_1.2Ni_0.15Mn_0.55Co_0.1O₂, is compared to two other transition-metal layered oxide materials, specifically LiNi_0.8Co_0.15Al_0.05O₂ (NCA) and Li_1.05(Ni_1/3Co_1/3Mn_1/3)_0.95O₂ (NMC). A more detailed electrochemical impedance spectroscopy (EIS) study is conducted on the LMR-NMC electrode, which includes a range of states-of-charge (SOCs) for both current directions (i.e. charge and discharge) and two relaxation times (i.e. hours and one hundred hours) before the EIS sweep. The LMR-NMC electrode EIS studies are supported by half-cell constant current and galvanostatic intermittent titration technique (GITT) studies. Two types of electrochemical models are utilized to examine the results. The first type is a lithium ion cell electrochemical model for intercalation active material electrodes that includes a complex active material/electrolyte interfacial structure. In conclusion, the other is a lithium ion half-cell electrochemical model that focuses on the unique composite structure of the bulk LMR-NMC materials.

An ab initio study on the transition paths from graphite to diamond under pressure

International Nuclear Information System (INIS)

Dong Xiao; Zhou Xiangfeng; Wang Huitian; Qian Guangrui; Zhao Zhisheng; Tian Yongjun

2013-01-01

We calculate and compare the transition paths from graphite to two types of diamond using the variable cell nudged elastic band method. For the phase transition from graphite to cubic diamond, we analyze in detail how the π bonds transit to the σ bonds in an electronic structure. Meanwhile, a new transition path with a lower energy barrier for the transformation from graphite to hexagonal diamond is discovered. The path has its own peculiar sp 2 –sp 3 bonding configurations, serving as a transition state. Further calculation suggests that the sp 2 –sp 3 transition state represents an expected general phenomenon for cold-compressed graphite. (paper)

A Support Vector Machine Approach for Truncated Fingerprint Image Detection from Sweeping Fingerprint Sensors

Science.gov (United States)

Chen, Chi-Jim; Pai, Tun-Wen; Cheng, Mox

2015-01-01

A sweeping fingerprint sensor converts fingerprints on a row by row basis through image reconstruction techniques. However, a built fingerprint image might appear to be truncated and distorted when the finger was swept across a fingerprint sensor at a non-linear speed. If the truncated fingerprint images were enrolled as reference targets and collected by any automated fingerprint identification system (AFIS), successful prediction rates for fingerprint matching applications would be decreased significantly. In this paper, a novel and effective methodology with low time computational complexity was developed for detecting truncated fingerprints in a real time manner. Several filtering rules were implemented to validate existences of truncated fingerprints. In addition, a machine learning method of supported vector machine (SVM), based on the principle of structural risk minimization, was applied to reject pseudo truncated fingerprints containing similar characteristics of truncated ones. The experimental result has shown that an accuracy rate of 90.7% was achieved by successfully identifying truncated fingerprint images from testing images before AFIS enrollment procedures. The proposed effective and efficient methodology can be extensively applied to all existing fingerprint matching systems as a preliminary quality control prior to construction of fingerprint templates. PMID:25835186

A Support Vector Machine Approach for Truncated Fingerprint Image Detection from Sweeping Fingerprint Sensors

Directory of Open Access Journals (Sweden)

Chi-Jim Chen

2015-03-01

Full Text Available A sweeping fingerprint sensor converts fingerprints on a row by row basis through image reconstruction techniques. However, a built fingerprint image might appear to be truncated and distorted when the finger was swept across a fingerprint sensor at a non-linear speed. If the truncated fingerprint images were enrolled as reference targets and collected by any automated fingerprint identification system (AFIS, successful prediction rates for fingerprint matching applications would be decreased significantly. In this paper, a novel and effective methodology with low time computational complexity was developed for detecting truncated fingerprints in a real time manner. Several filtering rules were implemented to validate existences of truncated fingerprints. In addition, a machine learning method of supported vector machine (SVM, based on the principle of structural risk minimization, was applied to reject pseudo truncated fingerprints containing similar characteristics of truncated ones. The experimental result has shown that an accuracy rate of 90.7% was achieved by successfully identifying truncated fingerprint images from testing images before AFIS enrollment procedures. The proposed effective and efficient methodology can be extensively applied to all existing fingerprint matching systems as a preliminary quality control prior to construction of fingerprint templates.

A Comparison of Teacher and Lecturer Perspectives on the Transition from Secondary to Tertiary Mathematics Education

Science.gov (United States)

Hong, Ye Yoon; Kerr, Suzanne; Klymchuk, Sergiy; McHardy, Johanna; Murphy, Priscilla; Spencer, Sue; Thomas, Michael O. J.; Watson, Peter

2009-01-01

The transition from school to tertiary study of mathematics comes under increasing scrutiny in research. This article reports on some findings from a project analysing the transition from secondary to tertiary education in mathematics. One key variable in this transition is the teacher or lecturer. This article deals with a small part of the data…

Tunable Landau-Zener transitions using continuous- and chirped-pulse-laser couplings

Science.gov (United States)

Sarreshtedari, Farrokh; Hosseini, Mehdi

2017-03-01

The laser coupled Landau-Zener avoided crossing has been investigated with an aim towards obtaining the laser source parameters for precise controlling of the state dynamics in a two-level quantum system. The conventional Landau-Zener equation is modified for including the interaction of the system with a laser field during a bias energy sweep and the obtained Hamiltonian is numerically solved for the investigation of the two-state occupation probabilities. We have shown that in the Landau-Zener process, using an additional laser source with controlled amplitude, frequency, and phase, the system dynamics could be arbitrarily engineered. This is while, by synchronous frequency sweeping of a chirped-pulse laser, the system could be guided into a resonance condition, which again gives the remarkable possibility for precise tuning and controlling of the quantum system dynamics.

Allowed and forbidden transition parameters for Fe XV

International Nuclear Information System (INIS)

Nahar, Sultana N.

2009-01-01

A comprehensive set of fine structure energy levels, oscillator strengths (f), line strengths (S), and radiative decay rates (A) for bound-bound transitions in Fe XV is presented. The allowed electric dipole (E1) transitions were obtained from the relativistic Breit-Pauli R-matrix method which is based on the close coupling approximation. A total of 507 fine structure energy levels with n ≤ 10, l ≤ 9, and 0 ≤ J ≤ 10 are found. They agree within 1% with the available observed energies. These energy levels yield a total of 27,812 E1, same-spin multiplets and intercombination transitions. The A values are in good agreement with those compiled by NIST and other existing values for most transitions. Forbidden transitions are obtained from a set of 20 configurations with orbitals ranging from 1s to 5f using the relativistic code SUPERSTRUCTURE (SS) in the Breit-Pauli approximation. From a set of 123 fine structure levels, a total of 6962 S and A values are presented for forbidden electric quadrupole (E2), electric octupole (E3), magnetic dipole (M1), and magnetic quadrupole (M2) transitions. The energies from SS calculations agree with observed energies to within 1-3%. A values for E2, M1 transitions agree very well with the available values for most transitions while those for M2 transitions show variable agreement. The large set of transition parameters presented should be applicable for both diagnostics and spectral modeling in the X-ray, ultraviolet, and optical regions of astrophysical plasmas.

Single-Column Model Simulations of Subtropical Marine Boundary-Layer Cloud Transitions Under Weakening Inversions: SCM SIMULATIONS OF CLOUD TRANSITIONS

Energy Technology Data Exchange (ETDEWEB)

Neggers, R. A. J. [Institute for Geophysics and Meteorology, Department of Geosciences, University of Cologne, Cologne Germany; Royal Netherlands Meteorological Institute, De Bilt The Netherlands; Ackerman, A. S. [NASA Goddard Institute for Space Studies, New York NY USA; Angevine, W. M. [CIRES, University of Colorado, Boulder CO USA; NOAA Earth System Research Laboratory, Boulder CO USA; Bazile, E. [Météo France/CNRM, Toulouse France; Beau, I. [Météo France/ENM, Toulouse France; Blossey, P. N. [Department of Atmospheric Sciences, University of Washington, Seattle WA USA; Boutle, I. A. [Met Office, Exeter UK; de Bruijn, C. [Royal Netherlands Meteorological Institute, De Bilt The Netherlands; Cheng, A. [NOAA Center for Weather and Climate Prediction, Environmental Modeling Center, College Park MD USA; van der Dussen, J. [Department of Geoscience and Remote Sensing, Delft University of Technology, Delft The Netherlands; Fletcher, J. [Department of Atmospheric Sciences, University of Washington, Seattle WA USA; University of Leeds, Leeds UK; Dal Gesso, S. [Institute for Geophysics and Meteorology, Department of Geosciences, University of Cologne, Cologne Germany; Royal Netherlands Meteorological Institute, De Bilt The Netherlands; Jam, A. [Météo-France/CNRM & CNRS/IPSL/LMD, Toulouse France; Kawai, H. [Meteorological Research Institute, Climate Research Department, Japan Meteorological Agency, Tsukuba Japan; Cheedela, S. K. [Department of Atmosphere in the Earth System, Max-Planck Institut für Meteorologie, Hamburg Germany; Larson, V. E. [Department of Mathematical Sciences, University of Wisconsin-Milwaukee, Milwaukee WI USA; Lefebvre, M. -P. [Météo-France/CNRM & CNRS/IPSL/LMD, Toulouse France; Lock, A. P. [Met Office, Exeter UK; Meyer, N. R. [Department of Mathematical Sciences, University of Wisconsin-Milwaukee, Milwaukee WI USA; de Roode, S. R. [Department of Geoscience and Remote Sensing, Delft University of Technology, Delft The Netherlands; de Rooy, W. [Royal Netherlands Meteorological Institute, De Bilt The Netherlands; Sandu, I. [Section of Physical Aspects, European Centre for Medium-Range Weather Forecasts, Reading UK; Xiao, H. [University of California at Los Angeles, Los Angeles CA USA; Pacific Northwest National Laboratory, Richland WA USA; Xu, K. -M. [NASA Langley Research Centre, Hampton VI USA

2017-10-01

Results are presented of the GASS/EUCLIPSE single-column model inter-comparison study on the subtropical marine low-level cloud transition. A central goal is to establish the performance of state-of-the-art boundary-layer schemes for weather and climate mod- els for this cloud regime, using large-eddy simulations of the same scenes as a reference. A novelty is that the comparison covers four different cases instead of one, in order to broaden the covered parameter space. Three cases are situated in the North-Eastern Pa- cific, while one reflects conditions in the North-Eastern Atlantic. A set of variables is considered that reflects key aspects of the transition process, making use of simple met- rics to establish the model performance. Using this method some longstanding problems in low level cloud representation are identified. Considerable spread exists among models concerning the cloud amount, its vertical structure and the associated impact on radia- tive transfer. The sign and amplitude of these biases differ somewhat per case, depending on how far the transition has progressed. After cloud breakup the ensemble median ex- hibits the well-known “too few too bright” problem. The boundary layer deepening rate and its state of decoupling are both underestimated, while the representation of the thin capping cloud layer appears complicated by a lack of vertical resolution. Encouragingly, some models are successful in representing the full set of variables, in particular the verti- cal structure and diurnal cycle of the cloud layer in transition. An intriguing result is that the median of the model ensemble performs best, inspiring a new approach in subgrid pa- rameterization.

Dimensionally similar studies of confinement and H-mode transition in ASDEX Upgrade and JET

International Nuclear Information System (INIS)

Ryter, F.; Stober, J.; Suttrop, W.

2001-01-01

Joint experiments on confinement and L-H transition were performed in ASDEX Upgrade and JET. The confinement experiments suggest that the invariance principle is not always fulfilled at high density. For the L-H transition studies, the dimensionless variables taken at the plasma edge can be in general only made identical per pair, due to the condition imposed by the L-H transition. This new approach to investigate the L-H physics suggests a weak dependence of the L-H transition mechanism on collisionality. (author)

Dimensionally similar studies of confinement and H-mode transition in ASDEX Upgrade and JET

International Nuclear Information System (INIS)

Ryter, F.; Stober, J.; Suttrop, W.

1999-01-01

Joint experiments on confinement and L-H transition were performed in ASDEX Upgrade and JET. The confinement experiments suggest that the invariance principle is not always fulfilled at high density. For the L-H transition studies, the dimensionless variables taken at the plasma edge can be in general only made identical per pair, due to the condition imposed by the L-H transition. This new approach to investigate the L-H physics suggests a weak dependence of the L-H transition mechanism on collisionality. (author)

Electronic traffic signs: Reflecting upon its transition

Energy Technology Data Exchange (ETDEWEB)

Arbaiza Martin, A.E.; Alba, A.L.; Hernando Mazon, A.; Blanch Mico, M.T.

2016-07-01

In our days we face a fundamental issue concerning road signs. We may display contents in vertical and horizontal format (static signs, variable message signs, road markings), either on a post, a gantry or a dashboard. And we foresee a coming age where the excellent matrix resolution of painted signs will be truly approached by the resolution of full matrix displays. But we also risk a babel context threatening the universal approach encouraged by international catalogues as the 1968 Convention (ECE/TRANS/196, 2007). And the fundamental risk comes from our decisions regarding how the transition from the contents and formats displayed on static message signs to the ones displayed on electronic signs (in gantries or dashboards) should be. Our work explores this issue specifically, considering the transition from Advance Direction Signs (static message signs, class G, 1 in the 1968 Convention) to what could be termed Advance Location Signs (signs concerning the location of variable events with regards to certain landmarks) developed as an adaptation of the G, 1 class to electronic traffic signs.(Author)

Modelling conditional correlations of asset returns: A smooth transition approach

DEFF Research Database (Denmark)

Silvennoinen, Annastiina; Teräsvirta, Timo

In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The time-varying conditional correlations change smoothly between two extreme states of constant correlations according to a predetermined or exogenous transition variable. An LM-test is d......In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The time-varying conditional correlations change smoothly between two extreme states of constant correlations according to a predetermined or exogenous transition variable. An LM......-test is derived to test the constancy of correlations and LM- and Wald tests to test the hypothesis of partially constant correlations. Analytical expressions for the test statistics and the required derivatives are provided to make computations feasible. An empirical example based on daily return series of ve...

Influence of climate variability, fire and phosphorus limitation on vegetation structure and dynamics of the Amazon-Cerrado border

Science.gov (United States)

Ane Dionizio, Emily; Heil Costa, Marcos; de Almeida Castanho, Andrea D.; Ferreira Pires, Gabrielle; Schwantes Marimon, Beatriz; Hur Marimon-Junior, Ben; Lenza, Eddie; Martins Pimenta, Fernando; Yang, Xiaojuan; Jain, Atul K.

2018-02-01

Climate, fire and soil nutrient limitation are important elements that affect vegetation dynamics in areas of the forest-savanna transition. In this paper, we use the dynamic vegetation model INLAND to evaluate the influence of interannual climate variability, fire and phosphorus (P) limitation on Amazon-Cerrado transitional vegetation structure and dynamics. We assess how each environmental factor affects net primary production, leaf area index and aboveground biomass (AGB), and compare the AGB simulations to an observed AGB map. We used two climate data sets (monthly average climate for 1961-1990 and interannual climate variability for 1948-2008), two data sets of total soil P content (one based on regional field measurements and one based on global data), and the INLAND fire module. Our results show that the inclusion of interannual climate variability, P limitation and fire occurrence each contribute to simulating vegetation types that more closely match observations. These effects are spatially heterogeneous and synergistic. In terms of magnitude, the effect of fire is strongest and is the main driver of vegetation changes along the transition. Phosphorus limitation, in turn, has a stronger effect on transitional ecosystem dynamics than interannual climate variability does. Overall, INLAND typically simulates more than 80 % of the AGB variability in the transition zone. However, the AGB in many places is clearly not well simulated, indicating that important soil and physiological factors in the Amazon-Cerrado border region, such as lithology, water table depth, carbon allocation strategies and mortality rates, still need to be included in the model.

Translating Glucose Variability Metrics into the Clinic via Continuous Glucose Monitoring: A Graphical User Interface for Diabetes Evaluation (CGM-GUIDE©)

Science.gov (United States)

Rawlings, Renata A.; Shi, Hang; Yuan, Lo-Hua; Brehm, William; Pop-Busui, Rodica

2011-01-01

Abstract Background Several metrics of glucose variability have been proposed to date, but an integrated approach that provides a complete and consistent assessment of glycemic variation is missing. As a consequence, and because of the tedious coding necessary during quantification, most investigators and clinicians have not yet adopted the use of multiple glucose variability metrics to evaluate glycemic variation. Methods We compiled the most extensively used statistical techniques and glucose variability metrics, with adjustable hyper- and hypoglycemic limits and metric parameters, to create a user-friendly Continuous Glucose Monitoring Graphical User Interface for Diabetes Evaluation (CGM-GUIDE©). In addition, we introduce and demonstrate a novel transition density profile that emphasizes the dynamics of transitions between defined glucose states. Results Our combined dashboard of numerical statistics and graphical plots support the task of providing an integrated approach to describing glycemic variability. We integrated existing metrics, such as SD, area under the curve, and mean amplitude of glycemic excursion, with novel metrics such as the slopes across critical transitions and the transition density profile to assess the severity and frequency of glucose transitions per day as they move between critical glycemic zones. Conclusions By presenting the above-mentioned metrics and graphics in a concise aggregate format, CGM-GUIDE provides an easy to use tool to compare quantitative measures of glucose variability. This tool can be used by researchers and clinicians to develop new algorithms of insulin delivery for patients with diabetes and to better explore the link between glucose variability and chronic diabetes complications. PMID:21932986

Successfully Transitioning Science Research to Space Weather Applications

Science.gov (United States)

Spann, James

2012-01-01

The awareness of potentially significant impacts of space weather on spaceand ground ]based technological systems has generated a strong desire in many sectors of government and industry to effectively transform knowledge and understanding of the variable space environment into useful tools and applications for use by those entities responsible for systems that may be vulnerable to space weather impacts. Essentially, effectively transitioning science knowledge to useful applications relevant to space weather has become important. This talk will present proven methodologies that have been demonstrated to be effective, and how in the current environment those can be applied to space weather transition efforts.

Reducing Demand Charges and Onsite Generation Variability Using Behind-the-Meter Energy Storage

Energy Technology Data Exchange (ETDEWEB)

Bhattarai, Bishnu P.; Myers, Kurt S.; Bush, Jason W.

2017-04-01

Electric utilities in the United States are increasingly employing demand charges and/or real-time pricing. This directive is bringing potential opportunities in deploying behindthe-meter energy storage (BMES) systems for various grid functionalities. This study quantifies techno-economic benefits of BMES in reducing demand charge and smoothing load/generation intermittencies, and determines how those benefits vary with onsite distributed photovoltaic. We proposed a two-stage control algorithm, whereby the first stage proactively determines costoptimal BMES configuration for reducing peak-demands and demand charges, and the second stage adaptively compensates intermittent generations and short load spikes that may otherwise increase the demand charges. The performance of the proposed algorithm is evaluated through a 24 hours time sweep simulation performed using data from smart microgrid testbed at Idaho National Laboratory (INL). The simulation results demonstrated that this research provides a simple but effective solution for peak shaving, demand charge reductions, and smoothing onsite PV variability.

Vortex variable range hopping in a conventional superconducting film

Science.gov (United States)

Percher, Ilana M.; Volotsenko, Irina; Frydman, Aviad; Shklovskii, Boris I.; Goldman, Allen M.

2017-12-01

The behavior of a disordered amorphous thin film of superconducting indium oxide has been studied as a function of temperature and magnetic field applied perpendicular to its plane. A superconductor-insulator transition has been observed, though the isotherms do not cross at a single point. The curves of resistance versus temperature on the putative superconducting side of this transition, where the resistance decreases with decreasing temperature, obey two-dimensional Mott variable-range hopping of vortices over wide ranges of temperature and resistance. To estimate the parameters of hopping, the film is modeled as a granular system and the hopping of vortices is treated in a manner analogous to hopping of charges. The reason the long-range interaction between vortices over the range of magnetic fields investigated does not lead to a stronger variation of resistance with temperature than that of two-dimensional Mott variable-range hopping remains unresolved.

Stable isotopes of transition and post-transition metals as tracers in environmental studies

Science.gov (United States)

Bullen, Tomas D.; Baskaran, Mark

2011-01-01

The transition and post-transition metals, which include the elements in Groups 3–12 of the Periodic Table, have a broad range of geological and biological roles as well as industrial applications and thus are widespread in the environment. Interdisciplinary research over the past decade has resulted in a broad understanding of the isotope systematics of this important group of elements and revealed largely unexpected variability in isotope composition for natural materials. Significant kinetic and equilibrium isotope fractionation has been observed for redox sensitive metals such as iron, chromium, copper, molybdenum and mercury, and for metals that are not redox sensitive in nature such as cadmium and zinc. In the environmental sciences, the isotopes are increasingly being used to understand important issues such as tracing of metal contaminant sources and fates, unraveling metal redox cycles, deciphering metal nutrient pathways and cycles, and developing isotope biosignatures that can indicate the role of biological activity in ancient and modern planetary systems.

From Transition Systems to Variability Models and from Lifted Model Checking Back to UPPAAL

DEFF Research Database (Denmark)

Dimovski, Aleksandar; Wasowski, Andrzej

2017-01-01

efficient lifted (family-based) model checking for real-time variability models. This reduces the cost of maintaining specialized family-based real-time model checkers. Real-time variability models can be model checked using the standard UPPAAL. We have implemented abstractions as syntactic source...

Planetary transit candidates in Corot-IRa01 field

Science.gov (United States)

Carpano, S.; Cabrera, J.; Alonso, R.; Barge, P.; Aigrain, S.; Almenara, J.-M.; Bordé, P.; Bouchy, F.; Carone, L.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fressin, F.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ofir, A.; Ollivier, M.; Janot-Pacheco, E.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider, J.; Wuchterl, G.

2009-10-01

Context: CoRoT is a pioneering space mission devoted to the analysis of stellar variability and the photometric detection of extrasolar planets. Aims: We present the list of planetary transit candidates detected in the first field observed by CoRoT, IRa01, the initial run toward the Galactic anticenter, which lasted for 60 days. Methods: We analysed 3898 sources in the coloured bands and 5974 in the monochromatic band. Instrumental noise and stellar variability were taken into account using detrending tools before applying various transit search algorithms. Results: Fifty sources were classified as planetary transit candidates and the most reliable 40 detections were declared targets for follow-up ground-based observations. Two of these targets have so far been confirmed as planets, CoRoT-1b and CoRoT-4b, for which a complete characterization and specific studies were performed. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with contributions from Austria, Belgium, Brazil, ESA, Germany, and Spain. Four French laboratories associated with the CNRS (LESIA, LAM, IAS ,OMP) collaborate with CNES on the satellite development. First CoRoT data are available to the public from the CoRoT archive: http://idoc-corot.ias.u-psud.fr.

Narrow-line laser cooling by adiabatic transfer

Science.gov (United States)

Norcia, Matthew A.; Cline, Julia R. K.; Bartolotta, John P.; Holland, Murray J.; Thompson, James K.

2018-02-01

We propose and demonstrate a novel laser cooling mechanism applicable to particles with narrow-linewidth optical transitions. By sweeping the frequency of counter-propagating laser beams in a sawtooth manner, we cause adiabatic transfer back and forth between the ground state and a long-lived optically excited state. The time-ordering of these adiabatic transfers is determined by Doppler shifts, which ensures that the associated photon recoils are in the opposite direction to the particle’s motion. This ultimately leads to a robust cooling mechanism capable of exerting large forces via a weak transition and with reduced reliance on spontaneous emission. We present a simple intuitive model for the resulting frictional force, and directly demonstrate its efficacy for increasing the total phase-space density of an atomic ensemble. We rely on both simulation and experimental studies using the 7.5 kHz linewidth 1S0 to 3P1 transition in 88Sr. The reduced reliance on spontaneous emission may allow this adiabatic sweep method to be a useful tool for cooling particles that lack closed cycling transitions, such as molecules.

Transiting exoplanets from the CoRoT space mission. IV. CoRoT-Exo-4b: a transiting planet in a 9.2 day synchronous orbit

Science.gov (United States)

Aigrain, S.; Collier Cameron, A.; Ollivier, M.; Pont, F.; Jorda, L.; Almenara, J. M.; Alonso, R.; Barge, P.; Bordé, P.; Bouchy, F.; Deeg, H.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Gillon, M.; Guillot, T.; Hatzes, A.; Lammer, H.; Lanza, A. F.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Paetzold, M.; Pinte, C.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.; Wuchter, G.; Zucker, S.

2008-09-01

CoRoT, the first space-based transit search, provides ultra-high-precision light curves with continuous time-sampling over periods of up to 5 months. This allows the detection of transiting planets with relatively long periods, and the simultaneous study of the host star's photometric variability. In this Letter, we report the discovery of the transiting giant planet CoRoT-Exo-4b and use the CoRoT light curve to perform a detailed analysis of the transit and determine the stellar rotation period. The CoRoT light curve was pre-processed to remove outliers and correct for orbital residuals and artefacts due to hot pixels on the detector. After removing stellar variability about each transit, the transit light curve was analysed to determine the transit parameters. A discrete autocorrelation function method was used to derive the rotation period of the star from the out-of-transit light curve. We determine the periods of the planetary orbit and star's rotation of 9.20205 ± 0.00037 and 8.87 ± 1.12 days respectively, which is consistent with this being a synchronised system. We also derive the inclination, i = 90.00_-0.085+0.000 in degrees, the ratio of the orbital distance to the stellar radius, a/Rs = 17.36-0.25+0.05, and the planet-to-star radius ratio R_p/R_s=0.1047-0.0022+0.0041. We discuss briefly the coincidence between the orbital period of the planet and the stellar rotation period and its possible implications for the system's migration and star-planet interaction history. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany, and Spain. The first CoRoT data will be available to the public in February 2009 from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/ Figures 1, 4 and 5 are only available in electronic form at http://www.aanda.org

On the use of transition matrix methods with extended ensembles.

Science.gov (United States)

Escobedo, Fernando A; Abreu, Charlles R A

2006-03-14

Different extended ensemble schemes for non-Boltzmann sampling (NBS) of a selected reaction coordinate lambda were formulated so that they employ (i) "variable" sampling window schemes (that include the "successive umbrella sampling" method) to comprehensibly explore the lambda domain and (ii) transition matrix methods to iteratively obtain the underlying free-energy eta landscape (or "importance" weights) associated with lambda. The connection between "acceptance ratio" and transition matrix methods was first established to form the basis of the approach for estimating eta(lambda). The validity and performance of the different NBS schemes were then assessed using as lambda coordinate the configurational energy of the Lennard-Jones fluid. For the cases studied, it was found that the convergence rate in the estimation of eta is little affected by the use of data from high-order transitions, while it is noticeably improved by the use of a broader window of sampling in the variable window methods. Finally, it is shown how an "elastic" window of sampling can be used to effectively enact (nonuniform) preferential sampling over the lambda domain, and how to stitch the weights from separate one-dimensional NBS runs to produce a eta surface over a two-dimensional domain.

Modal Transition Systems as the Basis for Interface Theories and Product Lines

DEFF Research Database (Denmark)

Nyman, Ulrik

and a subset of modal transition systems is proved. The developed interface theory, which can describe liveness properties, is also applied as a behavioral variability theory for product line development. The two last papers of the thesis concern themselves with modal and mixed transition systems. The first....... It also proves PSPACE-hardness for consistency of mixed specifications and establishes a number of reductions between the different decision problems. Keywords: Modeling, Software Product Lines, Embedded Software, Modal Refinement, Labeled Transition Systems, Modal Transition Systems, Mixed Transition......This thesis presents research taking its outset in component-based software development, interface theory and software product lines, as well as modeling formalisms for describing component based software systems and their interfaces. The main part of the thesis consists of five papers. The first...

Lyman-alpha transit observations of the warm rocky exoplanet GJ1132b

Science.gov (United States)

Waalkes, William; Berta-Thompson, Zachory K.; Charbonneau, David; Irwin, Jonathan; Newton, Elisabeth; Dittmann, Jason; Bourrier, Vincent; Ehrenreich, David; Kempton, Eliza; Will

2018-06-01

GJ1132b is one of the few known Earth-sized planets, and at 12pc away it is also one of the closest known transiting planets. With an equilibrium temperature of 500 K, this planet is too hot to be habitable but we can use it to learn about the presence and volatile content of rocky planet atmospheres around M dwarf stars. Using Hubble STIS spectra obtained during primary transit, we search for a Lyman-α transit. If we were to observe a deep Lyman-α transit, that would indicate the presence of a neutral hydrogen envelope flowing from GJ1132b. On the other hand, ruling out deep absorption from neutral hydrogen may indicate that this planet has either retained its volatiles or lost them very early in the star’s life. We carry out this analysis by extracting 1D spectra from the STIS pipeline, splitting the time-tagged spectra into higher resolution samples, and producing light curves of the red and blue wings of the Lyman-α line. We fit for the baseline stellar flux and transit depths in order to constrain the characteristics of the cloud of neutral hydrogen gas that may surround the planet. We do not conclusively detect a transit but the results provide an upper limit for the transit depth. We also analyze the stellar variability and Lyman-α spectrum of GJ1132, a slowly-rotating 0.18 solar mass M dwarf with previously uncharacterized UV activity. Understanding the role that UV variability plays in planetary atmospheres and volatile retention is crucial to assess atmospheric evolution and the habitability of cooler rocky planets.

Centroid vetting of transiting planet candidates from the Next Generation Transit Survey

Science.gov (United States)

Günther, Maximilian N.; Queloz, Didier; Gillen, Edward; McCormac, James; Bayliss, Daniel; Bouchy, Francois; Walker, Simon. R.; West, Richard G.; Eigmüller, Philipp; Smith, Alexis M. S.; Armstrong, David J.; Burleigh, Matthew; Casewell, Sarah L.; Chaushev, Alexander P.; Goad, Michael R.; Grange, Andrew; Jackman, James; Jenkins, James S.; Louden, Tom; Moyano, Maximiliano; Pollacco, Don; Poppenhaeger, Katja; Rauer, Heike; Raynard, Liam; Thompson, Andrew P. G.; Udry, Stéphane; Watson, Christopher A.; Wheatley, Peter J.

2017-11-01

The Next Generation Transit Survey (NGTS), operating in Paranal since 2016, is a wide-field survey to detect Neptunes and super-Earths transiting bright stars, which are suitable for precise radial velocity follow-up and characterization. Thereby, its sub-mmag photometric precision and ability to identify false positives are crucial. Particularly, variable background objects blended in the photometric aperture frequently mimic Neptune-sized transits and are costly in follow-up time. These objects can best be identified with the centroiding technique: if the photometric flux is lost off-centre during an eclipse, the flux centroid shifts towards the centre of the target star. Although this method has successfully been employed by the Kepler mission, it has previously not been implemented from the ground. We present a fully automated centroid vetting algorithm developed for NGTS, enabled by our high-precision autoguiding. Our method allows detecting centroid shifts with an average precision of 0.75 milli-pixel (mpix), and down to 0.25 mpix for specific targets, for a pixel size of 4.97 arcsec. The algorithm is now part of the NGTS candidate vetting pipeline and automatically employed for all detected signals. Further, we develop a joint Bayesian fitting model for all photometric and centroid data, allowing to disentangle which object (target or background) is causing the signal, and what its astrophysical parameters are. We demonstrate our method on two NGTS objects of interest. These achievements make NGTS the first ground-based wide-field transit survey ever to successfully apply the centroiding technique for automated candidate vetting, enabling the production of a robust candidate list before follow-up.

Youth with special health care needs: transition to adult health care services.

Science.gov (United States)

Oswald, Donald P; Gilles, Donna L; Cannady, Mariel S; Wenzel, Donna B; Willis, Janet H; Bodurtha, Joann N

2013-12-01

Transition to adult services for children and youth with special health care needs (CYSHCN) has emerged as an important event in the life course of individuals with disabilities. Issues that interfere with efficient transition to adult health care include the perspectives of stakeholders, age limits on pediatric service, complexity of health conditions, a lack of experienced healthcare professionals in the adult arena, and health care financing for chronic and complex conditions. The purposes of this study were to develop a definition of successful transition and to identify determinants that were associated with a successful transition. The 2007 Survey of Adult Transition and Health dataset was used to select variables to be considered for defining success and for identifying predictors of success. The results showed that a small percentage of young adults who participated in the 2007 survey had experienced a successful transition from their pediatric care.

Non-Linear Relationship between Economic Growth and CO₂ Emissions in China: An Empirical Study Based on Panel Smooth Transition Regression Models.

Science.gov (United States)

Wang, Zheng-Xin; Hao, Peng; Yao, Pei-Yi

2017-12-13

The non-linear relationship between provincial economic growth and carbon emissions is investigated by using panel smooth transition regression (PSTR) models. The research indicates that, on the condition of separately taking Gross Domestic Product per capita (GDPpc), energy structure (Es), and urbanisation level (Ul) as transition variables, three models all reject the null hypothesis of a linear relationship, i.e., a non-linear relationship exists. The results show that the three models all contain only one transition function but different numbers of location parameters. The model taking GDPpc as the transition variable has two location parameters, while the other two models separately considering Es and Ul as the transition variables both contain one location parameter. The three models applied in the study all favourably describe the non-linear relationship between economic growth and CO₂ emissions in China. It also can be seen that the conversion rate of the influence of Ul on per capita CO₂ emissions is significantly higher than those of GDPpc and Es on per capita CO₂ emissions.

Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates.

Directory of Open Access Journals (Sweden)

Antoine Muller

Full Text Available The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency.

Planetary transit candidates in CoRoT LRa01 field

DEFF Research Database (Denmark)

Carone, L.; Gandolfi, D.; Cabrera, J.

2012-01-01

We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008. We acquired and analyzed 7470 chromatic and 3938 monochromatic...... lightcurves. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves. (2 data files)....

Determination of strobilurin fungicide residues in fruits and vegetables by micellar electrokinetic capillary chromatography with sweeping.

Science.gov (United States)

Wang, Kun; Chen, Guan-hua; Wu, Xian; Shi, Jie; Guo, Dong-shan

2014-02-01

A new assay of micellar electrokinetic capillary chromatography with sweeping was developed to determine azoxystrobin, kresoxim-methyl and pyraclostrobin in fruits and vegetables. The key factors affecting resolution and peak height were studied and the optimum conditions were obtained for separation and enrichment. The running buffer consisted of 40 mM borate, 25 mM sodium dodecyl sulfate and 15% acetonitrile, and its pH was adjusted to 8.4. The sample was injected for 677 nL and the separation voltage was 25 kV. Under the optimum conditions, the enrichment factors of azoxystrobin, kresoxim-methyl and pyraclostrobin were 861, 550 and 403; the linear dynamic ranges were all 0.01-5.0 mg/L; the limits of detection were 0.002, 0.001 and 0.002 mg/kg; the recoveries of spiked samples were 85.1-98.5%, 87.5-97.0% and 89.1-99.1%, respectively. The assay can meet the requirement of maximum residue limits for these three strobilurin fungicides, and has been applied for determining their residues in fruits and vegetables.

Integrating Ecosystem Carbon Dynamics into State-and-Transition Simulation Models of Land Use/Land Cover Change

Science.gov (United States)

Sleeter, B. M.; Daniel, C.; Frid, L.; Fortin, M. J.

2016-12-01

State-and-transition simulation models (STSMs) provide a general approach for incorporating uncertainty into forecasts of landscape change. Using a Monte Carlo approach, STSMs generate spatially-explicit projections of the state of a landscape based upon probabilistic transitions defined between states. While STSMs are based on the basic principles of Markov chains, they have additional properties that make them applicable to a wide range of questions and types of landscapes. A current limitation of STSMs is that they are only able to track the fate of discrete state variables, such as land use/land cover (LULC) classes. There are some landscape modelling questions, however, for which continuous state variables - for example carbon biomass - are also required. Here we present a new approach for integrating continuous state variables into spatially-explicit STSMs. Specifically we allow any number of continuous state variables to be defined for each spatial cell in our simulations; the value of each continuous variable is then simulated forward in discrete time as a stochastic process based upon defined rates of change between variables. These rates can be defined as a function of the realized states and transitions of each cell in the STSM, thus providing a connection between the continuous variables and the dynamics of the landscape. We demonstrate this new approach by (1) developing a simple IPCC Tier 3 compliant model of ecosystem carbon biomass, where the continuous state variables are defined as terrestrial carbon biomass pools and the rates of change as carbon fluxes between pools, and (2) integrating this carbon model with an existing LULC change model for the state of Hawaii, USA.

Transition Heat Transfer Modeling Based on the Characteristics of Turbulent Spots

Science.gov (United States)

Simon, Fred; Boyle, Robert

1998-01-01

While turbulence models are being developed which show promise for simulating the transition region on a turbine blade or vane, it is believed that the best approach with the greatest potential for practical use is the use of models which incorporate the physics of turbulent spots present in the transition region. This type of modeling results in the prediction of transition region intermittency which when incorporated in turbulence models give a good to excellent prediction of the transition region heat transfer. Some models are presented which show how turbulent spot characteristics and behavior can be employed to predict the effect of pressure gradient and Mach number on the transition region. The models predict the spot formation rate which is needed, in addition to the transition onset location, in the Narasimha concentrated breakdown intermittency equation. A simplified approach is taken for modeling turbulent spot growth and interaction in the transition region which utilizes the turbulent spot variables governing transition length and spot generation rate. The models are expressed in terms of spot spreading angle, dimensionless spot velocity, dimensionless spot area, disturbance frequency and Mach number. The models are used in conjunction with a computer code to predict the effects of pressure gradient and Mach number on the transition region and compared with VKI experimental turbine data.

Exploring the Factors that Impact on Transit Use through an Ordered Probit Model: the Case of Metro of Madrid

Energy Technology Data Exchange (ETDEWEB)

Eboli, L.; Forciniti, C.; Mazzulla, G.; Calvo, F.

2016-07-01

The configuration of urban areas is the result of a cyclic relationship between land use and transportation system: the changes in transportation system arrangements influence the localisation of residence and economic activities, as well as the changes in land use affect transportation system characteristics. In this context, by operating on land use, travel demand can be shift from the individual transportation modes to transit systems. In the literature, many conceptual models were proposed to describe the complex relationship between land use and travel behaviour. In addition to spatial variation, the study of travel demand shows the categorical variation of variables. This work aims to analyse the influence of the categorical variation of variables impacting on transit use. An ordered probit model is proposed for evaluating how transit use depends on variables related to socio-economic characteristics of population, territorial features, accessibility, and transportation system. The study case is Madrid metro network (Spain). The results show a strong influence of characteristics of population and land use variables on daily trips made using metro system and highlighted the aspects that mainly impact on the choice to travel by metro, providing useful suggestions for shifting people from individual transportation mode to transit systems. (Author)

Modeling Enzymatic Transition States by Force Field Methods

DEFF Research Database (Denmark)

Hansen, Mikkel Bo; Jensen, Hans Jørgen Aagaard; Jensen, Frank

2009-01-01

The SEAM method, which models a transition structure as a minimum on the seam of two diabatic surfaces represented by force field functions, has been used to generate 20 transition structures for the decarboxylation of orotidine by the orotidine-5'-monophosphate decarboxylase enzyme. The dependence...... of the TS geometry on the flexibility of the system has been probed by fixing layers of atoms around the active site and using increasingly larger nonbonded cutoffs. The variability over the 20 structures is found to decrease as the system is made more flexible. Relative energies have been calculated...... by various electronic structure methods, where part of the enzyme is represented by a force field description and the effects of the solvent are represented by a continuum model. The relative energies vary by several hundreds of kJ/mol between the transition structures, and tests showed that a large part...

Characteristics of a gas-jet transport system for an on-line isotope separator

International Nuclear Information System (INIS)

Kawade, K.; Yamamoto, H.; Amano, H.; Hanada, M.; Katoh, T.; Okano, K.; Kawase, Y.; Fujiwara, I.

1982-01-01

Basic characteristics of a gas-jet transport system for an on-line isotope separator have been investigated using a 252 Cf source and a 235 U fission source. The transport efficiency of fission products through a capillary has been measured to be about 60% for the 235 U fission source. The sweep-out time of fission products through a target chamber and the transit time through a capillary have been measured for He, N 2 and CO 2 gases at several pressures. The measured sweep-out times have been almost equal to the exchange over time of the gas. The transit times have been found to be reasonably predicted by calculations. The transport system has been incorporated into the KUR-ISOL and is used for the study of short-lived nuclei. (orig.)

Hidden Markov latent variable models with multivariate longitudinal data.

Science.gov (United States)

Song, Xinyuan; Xia, Yemao; Zhu, Hongtu

2017-03-01

Cocaine addiction is chronic and persistent, and has become a major social and health problem in many countries. Existing studies have shown that cocaine addicts often undergo episodic periods of addiction to, moderate dependence on, or swearing off cocaine. Given its reversible feature, cocaine use can be formulated as a stochastic process that transits from one state to another, while the impacts of various factors, such as treatment received and individuals' psychological problems on cocaine use, may vary across states. This article develops a hidden Markov latent variable model to study multivariate longitudinal data concerning cocaine use from a California Civil Addict Program. The proposed model generalizes conventional latent variable models to allow bidirectional transition between cocaine-addiction states and conventional hidden Markov models to allow latent variables and their dynamic interrelationship. We develop a maximum-likelihood approach, along with a Monte Carlo expectation conditional maximization (MCECM) algorithm, to conduct parameter estimation. The asymptotic properties of the parameter estimates and statistics for testing the heterogeneity of model parameters are investigated. The finite sample performance of the proposed methodology is demonstrated by simulation studies. The application to cocaine use study provides insights into the prevention of cocaine use. © 2016, The International Biometric Society.

Equilibrium Transitions from Non Renewable Energy to Renewable Energy under Capacity Constraints

OpenAIRE

Amigues, Jean-Pierre; Ayong Le Kama, Alain; Moreaux, Michel

2013-01-01

We study the transition between non-renewable and renewable energy sources with adjustment costs over the production capacity of renewable energy. Assuming constant variable marginal costs for both energy sources, convex adjustment costs and a more expensive renewable energy, we show the following. With sufficiently abundant non-renewable energy endowments, the dynamic equilibrium path is composed of a first time phase of only non-renewable energy use followed by a transition phase substituti...

Reactive scattering theory for molecular transitions in time-dependent fields

International Nuclear Information System (INIS)

Peskin, U.; Miller, W.H.

1995-01-01

A new approach is introduced for computing probabilities of molecular transitions in time-dependent fields. The method is based on the stationary (t,t') representation of the Schroedinger equation and is shown to be equivalent to infinite order time-dependent perturbation theory. Bound-to-bound (i.e., photoexcitation) and bound-to-continuum (i.e., photoreaction) transitions are regarded as reactive collisions with the ''time coordinate'' as the reaction coordinate in an extended Hilbert space. A numerical method based on imposing absorbing boundary conditions for the time coordinate in a discrete variable representation framework is introduced. A single operation of the Green's operator provides all the state-specific transition probabilities as well as partial state-resolved (inclusive) reaction probabilities. Illustrative numerical applications are given for model systems

Poisson and Porter-Thomas fluctuations in off-yrast rotational transitions

International Nuclear Information System (INIS)

Matsuo, M.; Doessing, T.; Herskind, B.; Frauendorf, S.

1993-01-01

Fluctuations associated with stretched E2 transitions from high-spin levels in nuclei around 168 Yb are investigated by a cranked shell model extended to include residual two-body interactions. In the cranked mean-field model without residual interactions, it is found that gamma-ray energies behave like random variables and the energy spectra show Poisson fluctuation. With two-body residual interactions included, the discrete transition pattern with unmixed rotational bands is still valid up to around 600 keV above yrast, in good agreement with experiments. At higher excitation energy, a gradual onset of rotational damping emerges. At 1.8 MeV above yrast, complete damping is observed with GOE-type fluctuations for both energy levels and transition strengths (Porter-Thomas fluctuations). (orig.)

Genomic Footprints of Selective Sweeps from Metabolic Resistance to Pyrethroids in African Malaria Vectors Are Driven by Scale up of Insecticide-Based Vector Control.

Science.gov (United States)

Barnes, Kayla G; Weedall, Gareth D; Ndula, Miranda; Irving, Helen; Mzihalowa, Themba; Hemingway, Janet; Wondji, Charles S

2017-02-01

Insecticide resistance in mosquito populations threatens recent successes in malaria prevention. Elucidating patterns of genetic structure in malaria vectors to predict the speed and direction of the spread of resistance is essential to get ahead of the 'resistance curve' and to avert a public health catastrophe. Here, applying a combination of microsatellite analysis, whole genome sequencing and targeted sequencing of a resistance locus, we elucidated the continent-wide population structure of a major African malaria vector, Anopheles funestus. We identified a major selective sweep in a genomic region controlling cytochrome P450-based metabolic resistance conferring high resistance to pyrethroids. This selective sweep occurred since 2002, likely as a direct consequence of scaled up vector control as revealed by whole genome and fine-scale sequencing of pre- and post-intervention populations. Fine-scaled analysis of the pyrethroid resistance locus revealed that a resistance-associated allele of the cytochrome P450 monooxygenase CYP6P9a has swept through southern Africa to near fixation, in contrast to high polymorphism levels before interventions, conferring high levels of pyrethroid resistance linked to control failure. Population structure analysis revealed a barrier to gene flow between southern Africa and other areas, which may prevent or slow the spread of the southern mechanism of pyrethroid resistance to other regions. By identifying a genetic signature of pyrethroid-based interventions, we have demonstrated the intense selective pressure that control interventions exert on mosquito populations. If this level of selection and spread of resistance continues unabated, our ability to control malaria with current interventions will be compromised.

Genomic Footprints of Selective Sweeps from Metabolic Resistance to Pyrethroids in African Malaria Vectors Are Driven by Scale up of Insecticide-Based Vector Control.

Directory of Open Access Journals (Sweden)

Kayla G Barnes

2017-02-01

Full Text Available Insecticide resistance in mosquito populations threatens recent successes in malaria prevention. Elucidating patterns of genetic structure in malaria vectors to predict the speed and direction of the spread of resistance is essential to get ahead of the 'resistance curve' and to avert a public health catastrophe. Here, applying a combination of microsatellite analysis, whole genome sequencing and targeted sequencing of a resistance locus, we elucidated the continent-wide population structure of a major African malaria vector, Anopheles funestus. We identified a major selective sweep in a genomic region controlling cytochrome P450-based metabolic resistance conferring high resistance to pyrethroids. This selective sweep occurred since 2002, likely as a direct consequence of scaled up vector control as revealed by whole genome and fine-scale sequencing of pre- and post-intervention populations. Fine-scaled analysis of the pyrethroid resistance locus revealed that a resistance-associated allele of the cytochrome P450 monooxygenase CYP6P9a has swept through southern Africa to near fixation, in contrast to high polymorphism levels before interventions, conferring high levels of pyrethroid resistance linked to control failure. Population structure analysis revealed a barrier to gene flow between southern Africa and other areas, which may prevent or slow the spread of the southern mechanism of pyrethroid resistance to other regions. By identifying a genetic signature of pyrethroid-based interventions, we have demonstrated the intense selective pressure that control interventions exert on mosquito populations. If this level of selection and spread of resistance continues unabated, our ability to control malaria with current interventions will be compromised.

Climatology of winter transition days for the contiguous USA, 1951-2007

Science.gov (United States)

Hondula, David M.; Davis, Robert E.

2011-01-01

In middle and high latitudes, climate change could impact the frequency and characteristics of frontal passages. Although transitions between air masses are significant features of the general circulation that influence human activities and other surface processes, they are much more difficult to objectively identify than single variables like temperature or even extreme events like fires, droughts, and floods. The recently developed Spatial Synoptic Classification (SSC) provides a fairly objective means of identifying frontal passages. In this research, we determine the specific meteorological patterns represented by the SSC's Transition category, a "catch-all" group that attempts to identify those days that cannot be characterized as a single, homogeneous air mass type. The result is a detailed transition climatology for the continental USA. We identify four subtypes of the Transition category based on intra-day sea level pressure change and dew point temperature change. Across the contiguous USA, most transition days are identified as cold fronts and warm fronts during the winter season. Among the two less common subtypes, transition days in which the dew point temperature and pressure both rise are more frequently observed across the western states, and days in which both variables fall are more frequently observed in coastal regions. The relative frequencies of wintertime warm and cold fronts have changed over the period 1951-2007. Relative cold front frequency has significantly increased in the Northeast and Midwest regions, and warm front frequencies have declined in the Midwest, Rocky Mountain, and Pacific Northwest regions. The overall shift toward cold fronts and away from warm fronts across the northern USA arises from a combination of an enhanced ridge over western North America and a northward shift of storm tracks throughout the mid-latitudes. These results are consistent with projections of climate change associated with elevated greenhouse gas

On the search for experimentally observed grain boundary phase transitions

International Nuclear Information System (INIS)

Balluffi, R.W.; Hsieh, T.E.

1987-07-01

The phase space for a heterogeneous system containing a grain boundary involves a relatively large number of variables (i.e., at least six plus the number of components), and it is therefore conceptually possible to induce a large variety of grain boundary phase transitions by selectively varying these parameters. Despite this, a review of the literature reveals that there have been virtually no clear-cut experimental observations of transitions reported in which the boundary structure has been observed as a function of time under well defined conditions. In current work, we are searching for roughening/faceting transitions and melting transitions for boundaries in Al by hot stage transmission electron microscopy. A clear example of a reversible roughening/faceting transition has been found. No evidence for melting has been found for temperatures as high as 0.96 T/sub m/ (by monitoring GBD core delocalization in several special boundaries with Σ ≤ 13) or 0.999 T/sub m/ (by observing the local diffraction contrast at general boundaries in polycrystalline specimens)

Whole-bowel transit in patients with the irritable bowel syndrome

International Nuclear Information System (INIS)

Hardy, J.G.; Clark, A.G.; Wood, E.; Reynolds, J.R.

1986-01-01

The transit of radiolabelled preparations through the stomach, small intestine and colon was monitored in ten patients with the irritable bowel syndrome. Five patients complained of diarrhoea, and five complained of constipation. The preparations comprised a non-disintegrating capsule and a multiparticulate system. Both preparations emptied from the stomach together and at the same rates in both groups of patients. In the patients complaining of constipation, the transit times through the small intestine were the same for both preparations. In the patients complaining of diarrhoea, the capsule passed through the small intestine slightly faster than the particles, but there were no significant differences in the small-intestinal transit rates of the two patient groups. Within the colon, the transit of the capsule was faster than that of the small particles. Although movement through the colon was, on average, faster in the group of patients complaining of diarrhoea, there was considerable intersubject variability, and the differences in transit rates between the two patient groups were not statistically significant. (orig.)

Whole-bowel transit in patients with the irritable bowel syndrome

Energy Technology Data Exchange (ETDEWEB)

Hardy, J.G.; Clark, A.G.; Wood, E.; Reynolds, J.R.

1986-02-01

The transit of radiolabelled preparations through the stomach, small intestine and colon was monitored in ten patients with the irritable bowel syndrome. Five patients complained of diarrhoea, and five complained of constipation. The preparations comprised a non-disintegrating capsule and a multiparticulate system. Both preparations emptied from the stomach together and at the same rates in both groups of patients. In the patients complaining of constipation, the transit times through the small intestine were the same for both preparations. In the patients complaining of diarrhoea, the capsule passed through the small intestine slightly faster than the particles, but there were no significant differences in the small-intestinal transit rates of the two patient groups. Within the colon, the transit of the capsule was faster than that of the small particles. Although movement through the colon was, on average, faster in the group of patients complaining of diarrhoea, there was considerable intersubject variability, and the differences in transit rates between the two patient groups were not statistically significant. (orig.).

Employment outcomes of transition-aged adults with autism spectrum disorders: a state of the States report.

Science.gov (United States)

Burgess, Sloane; Cimera, Robert E

2014-01-01

The primary purpose of this study was to evaluate the employment outcomes of transition-aged adults with autism spectrum disorders (ASD) served by vocational rehabilitation services (VR) over the last 10 years by state. A secondary purpose was to compare employment outcomes of individuals with ASD to those of the overall transition-aged population served by VR for the same time period. Although there was variability both within and among states, the results of this study indicate that, over time, the number of young adults with ASD seeking VR services has increased; however, employment outcomes including the percent of adults with ASD achieving employment, the number of hours worked, and wages earned have not improved for this group. The cost to provide VR services to transition-aged adults with ASD was relatively stable over time. Transition-aged adults with ASD were more likely to become successfully employed as a result of receiving VR services than the overall population of transition-aged adults served by VR. However, the employed transition-aged adults consistently worked fewer hours and earned lower wages than those in the overall population. Factors that may influence variability within and among states, and between groups, and implications for research and practice are discussed.

Acoustic emission in a superconductor (Nb-Ti) during magnetic field and current sweep

International Nuclear Information System (INIS)

Nomura, Harehiko

1980-01-01

Though superconducting magnets are indispensable in the fields of nuclear fusion, MHD power generation, high energy technology, and the trains using magnetic levitation, the safety of the magnets used for those fields is required to be fully investigated because their accumulating energy reaches up to several GJ. For this purpose, the improvement of monitoring techniques is extremely important to grasp exactly the magnetization of such large energy magnets. Although the detection of the terminal voltage of the magnets has been mainly used so far, the purpose has not yet been fulfilled because various phenomena appear in the form of noises in the terminal voltage. The authors have found the monitoring method using acoustic emission in a system completely independent from voltage observation. From this viewpoint, the experiments have been performed aiming at the generation of acoustic emission in conjunction with magnetization out of the fine structure of super-conductors, taking notice of the emitted sound frequency ranging over several hundred kHz. The results and investigation revealed that the superconductor itself emitted ultrasonic sound. It was found that the observation of this acoustic power intensity was able to monitor not only the magnetization of superconductors but also its current sweep. Since the motion of the magnetic flux is converted into the signal of acoustic field, this measuring method is less affected by noise disturbance from electromagnetic systems, and is expected to be useful for the researches on analyzing superconductor characteristics. (Wakatsuki, Y.)

Electron impact excitation of 1'S-2'S transition in helium

International Nuclear Information System (INIS)

Mohanty, J.P.; Singh, C.S.

1989-01-01

The modified variable-charge Coulomb-projected Born approximation is applied to electron impact excitation of 1 1 S-2 1 S transition in helium. The results are compared with other theoretical and experimental results. (author). 30 refs., 4 figs

Mixed-order phase transition of the contact process near multiple junctions.

Science.gov (United States)

Juhász, Róbert; Iglói, Ferenc

2017-02-01

We have studied the phase transition of the contact process near a multiple junction of M semi-infinite chains by Monte Carlo simulations. As opposed to the continuous transitions of the translationally invariant (M=2) and semi-infinite (M=1) system, the local order parameter is found to be discontinuous for M>2. Furthermore, the temporal correlation length diverges algebraically as the critical point is approached, but with different exponents on the two sides of the transition. In the active phase, the estimate is compatible with the bulk value, while in the inactive phase it exceeds the bulk value and increases with M. The unusual local critical behavior is explained by a scaling theory with an irrelevant variable, which becomes dangerous in the inactive phase. Quenched spatial disorder is found to make the transition continuous in agreement with earlier renormalization group results.

Exoplanet Transits of Stellar Active Regions

Science.gov (United States)

Giampapa, Mark S.; Andretta, Vincenzo; Covino, Elvira; Reiners, Ansgar; Esposito, Massimiliano

2018-01-01

We report preliminary results of a program to obtain high spectral- and temporal-resolution observations of the neutral helium triplet line at 1083.0 nm in transiting exoplanet systems. The principal objective of our program is to gain insight on the properties of active regions, analogous to solar plages, on late-type dwarfs by essentially using exoplanet transits as high spatial resolution probes of the stellar surface within the transit chord. The 1083 nm helium line is a particularly appropriate diagnostic of magnetized areas since it is weak in the quiet photosphere of solar-type stars but appears strongly in absorption in active regions. Therefore, during an exoplanet transit over the stellar surface, variations in its absorption equivalent width can arise that are functions of the intrinsic strength of the feature in the active region and the known relative size of the exoplanet. We utilized the Galileo Telescope and the GIANO-B near-IR echelle spectrograph to obtain 1083 nm spectra during transits in bright, well-known systems that include HD 189733, HD 209458, and HD 147506 (HAT-P-2). We also obtained simultaneous auxiliary data on the same telescope with the HARPS-N UV-Visible echelle spectrograph. We will present preliminary results from our analysis of the observed variability of the strength of the He I 1083 nm line during transits.Acknowledgements: Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The NSO is operated by AURA under a cooperative agreement with the NSF.

Investigation of clinical pharmacokinetic variability of an opioid antagonist through physiologically based absorption modeling.

Science.gov (United States)

Ding, Xuan; He, Minxia; Kulkarni, Rajesh; Patel, Nita; Zhang, Xiaoyu

2013-08-01

Identifying the source of inter- and/or intrasubject variability in pharmacokinetics (PK) provides fundamental information in understanding the pharmacokinetics-pharmacodynamics relationship of a drug and project its efficacy and safety in clinical populations. This identification process can be challenging given that a large number of potential causes could lead to PK variability. Here we present an integrated approach of physiologically based absorption modeling to investigate the root cause of unexpectedly high PK variability of a Phase I clinical trial drug. LY2196044 exhibited high intersubject variability in the absorption phase of plasma concentration-time profiles in humans. This could not be explained by in vitro measurements of drug properties and excellent bioavailability with low variability observed in preclinical species. GastroPlus™ modeling suggested that the compound's optimal solubility and permeability characteristics would enable rapid and complete absorption in preclinical species and in humans. However, simulations of human plasma concentration-time profiles indicated that despite sufficient solubility and rapid dissolution of LY2196044 in humans, permeability and/or transit in the gastrointestinal (GI) tract may have been negatively affected. It was concluded that clinical PK variability was potentially due to the drug's antagonism on opioid receptors that affected its transit and absorption in the GI tract. Copyright © 2013 Wiley Periodicals, Inc.

Applying Transition Action Detail Strategy on Written Text of EFL Young Learners

Directory of Open Access Journals (Sweden)

Yeasy Agustina Sari

2017-06-01

Full Text Available Mastering English, as foreign language need a lot of time since it is a continuing process. English foreign language of young learners, however, can’t be mastered by memorizing. The young learners should have strategy, which can be used as the direction of the classroom activites to help the students enhancing of language skill, specially in writting. There were the problem to be solved in this study, namely the students have difficult to construct the written text. The strategies which were used in the learning process were boring. Hence, the researcher tried to solve students’ difficulty in written text through Transition Action Detail Strategy. This study focused on two variables. The independent variable was Transition Action Detail Strategy, meanwhile dependent variable was written text. The researcher used true experimental design which consist of control group and experimental group. The subject of this research was students of young learner at the eight grade of English Course at Payakumbuh. The result revealed that Transition Action Detail Strategy was a good strategy that can influence the students’ narrative text. By using df.70, the writer not found it in the table. Because 70 was higher than 60 and smaller than 120. Then, the results from interpolation by using df.70, it could be known that the critical value of   t-table for the 5% level was 1.990, the critical value of t-table for the 1% level was 2.638. From these all the data analysis, it can be seen that t-observed (4.763 was higher than t-table (5% =1.990, 1% = 2.638. The data confirm that t-observed  is higher than t-table, therefore it can be inferred that Ha is accepted and Ho is rejected. It means that there is significant influence of applying Transition Action Detail Strategy on Wwritten Text of Young learners.   Key words: Transition Action Detail Strategy, Young Learners, English Foreign Language, English  Course.

Characterizing Phase Transitions in a Model of Neutral Evolutionary Dynamics

Science.gov (United States)

Scott, Adam; King, Dawn; Bahar, Sonya

2013-03-01

An evolutionary model was recently introduced for sympatric, phenotypic evolution over a variable fitness landscape with assortative mating (Dees & Bahar 2010). Organisms in the model are described by coordinates in a two-dimensional phenotype space, born at random coordinates with limited variation from their parents as determined by a mutation parameter, mutability. The model has been extended to include both neutral evolution and asexual reproduction in Scott et al (submitted). It has been demonstrated that a second order, non-equilibrium phase transition occurs for the temporal dynamics as the mutability is varied, for both the original model and for neutral conditions. This transition likely belongs to the directed percolation universality class. In contrast, the spatial dynamics of the model shows characteristics of an ordinary percolation phase transition. Here, we characterize the phase transitions exhibited by this model by determining critical exponents for the relaxation times, characteristic lengths, and cluster (species) mass distributions. Missouri Research Board; J.S. McDonnell Foundation

A multiple-field coupled resistive transition model for superconducting Nb3Sn

Science.gov (United States)

Yang, Lin; Ding, He; Zhang, Xin; Qiao, Li

2016-12-01

A study on the superconducting transition width as functions of the applied magnetic field and strain is performed in superconducting Nb3Sn. A quantitative, yet universal phenomenological resistivity model is proposed. The numerical simulation by the proposed model shows predicted resistive transition characteristics under variable magnetic fields and strain, which in good agreement with the experimental observations. Furthermore, a temperature-modulated magnetoresistance transition behavior in filamentary Nb3Sn conductors can also be well described by the given model. The multiple-field coupled resistive transition model is helpful for making objective determinations of the high-dimensional critical surface of Nb3Sn in the multi-parameter space, offering some preliminary information about the basic vortex-pinning mechanisms, and guiding the design of the quench protection system of Nb3Sn superconducting magnets.

Thermodynamic and kinetic theory of nucleation, deliquescence and efflorescence transitions in the ensemble of droplets on soluble particles.

Science.gov (United States)

Shchekin, Alexander K; Shabaev, Ilya V; Hellmuth, Olaf

2013-02-07

Thermodynamic and kinetic peculiarities of nucleation, deliquescence and efflorescence transitions in the ensemble of droplets formed on soluble condensation nuclei from a solvent vapor have been considered. The interplay of the effects of solubility and the size of condensation nuclei has been analyzed. Activation barriers for the deliquescence and phase transitions and for the reverse efflorescence transition have been determined as functions of the relative humidity of the vapor-gas atmosphere, initial size, and solubility of condensation nuclei. It has been demonstrated that, upon variations in the relative humidity of the atmosphere, the crossover in thermodynamically stable and unstable variables of the droplet state takes place. The physical meaning of stable and unstable variables has been clarified. The kinetic equations for establishing equilibrium and steady distributions of binary droplets have been solved. The specific times for relaxation, deliquescence and efflorescence transitions have been calculated.

Last Card: Can Nigeria Survive Another Transition? | Obi | African ...

African Journals Online (AJOL)

This essay addresses an important variable in Nigerian politics, namely, ethnicity and the ways in which it affects the conduct of national affairs. It represents an effort at theorizing the role and place of ethnicity in the transition from authoritarianism in a multi-ethnic setting such as that represented by Nigeria. Drawing on ...

Ethnicity and Transition to Democracy in Nigeria: Explaining the ...

African Journals Online (AJOL)

This essay addresses an important variable in Nigerian politics, namely, ethnicity and the ways in which it affects the conduct of national affairs. It represents an effort at theorizing the role and place of ethnicity in the transition from authoritarianism in a multi-ethnic setting such as that represented by Nigeria. Drawing on ...

The Transition from School to University in Mathematics: Which Influence Do School-Related Variables Have?

Science.gov (United States)

Rach, Stefanie; Heinze, Aiso

2017-01-01

Particularly in mathematics, the transition from school to university often appears to be a substantial hurdle in the individual learning biography. Differences between the characters of school mathematics and scientific university mathematics as well as different demands related to the learning cultures in both institutions are discussed as…

The Role of FDI in the Economic Development of Transition Countries

Directory of Open Access Journals (Sweden)

Jelena Tast

2014-09-01

Full Text Available FDI are considered a key instrument in the process of transforming the former centrally planned economies and stimulate economic growth in the transition period. Economic theory suggests that FDI are an important factor for the economic growth of the host-country, while according to empirical research in general, there is a positive correlation between FDI and the economic growth, but the causality direction is not clear: FDI inflow stimulates economic growth, but in the same time FDI inflows grow with the country’s economic development. Therefore, the objective of research in the paper is the relationship between FDI and economic growth in SEE and CIS countries. The relationship between the FDI and the economic growth in transition countries is examined by linear regression correlation of the relevant variables, covering the period from 2004 to 2011. Through the Pierce coefficient and the coefficient of determination, the interaction between the relevant variables and the dependence intensity is examine, and in this context general conclusions are drawn about the effects of FDI in the SEE and CIS countries. At the same time, the beta-coefficient is used to examine the value of the change in each variable separately, in order to make a more detailed analysis of the results obtained. In order to determine the direction of causality between the FDI and the economic growth of the country, research is carried out the influence of the transition indicators on the FDI inflow in the SEE and CIS countries from 2004 to 2011.

Theory of quantum metal to superconductor transitions in highly conducting systems

Energy Technology Data Exchange (ETDEWEB)

Spivak, B.

2010-04-06

We derive the theory of the quantum (zero temperature) superconductor to metal transition in disordered materials when the resistance of the normal metal near criticality is small compared to the quantum of resistivity. This can occur most readily in situations in which 'Anderson's theorem' does not apply. We explicitly study the transition in superconductor-metal composites, in an swave superconducting film in the presence of a magnetic field, and in a low temperature disordered d-wave superconductor. Near the point of the transition, the distribution of the superconducting order parameter is highly inhomogeneous. To describe this situation we employ a procedure which is similar to that introduced by Mott for description of the temperature dependence of the variable range hopping conduction. As the system approaches the point of the transition from the metal to the superconductor, the conductivity of the system diverges, and the Wiedemann-Franz law is violated. In the case of d-wave (or other exotic) superconductors we predict the existence of (at least) two sequential transitions as a function of increasing disorder: a d-wave to s-wave, and then an s-wave to metal transition.

Temporal variability in epifaunal assemblages associated with temperate gorgonian gardens

KAUST Repository

Dias, I.M.; Curdia, Joao; Cunha, M.R.; Santos, M.N.; Carvalho, Susana

2015-01-01

The present study is one of the few that investigate the temporal variability of epifaunal assemblages associated with coral species, particularly the octocorals Eunicella gazella and Leptogorgia lusitanica in south Portugal. The results suggest time rather than colony size as a primary driver of the ecological patterns of these assemblages, which were dominated by amphipods, molluscs and polychaetes. Temporal variability was linked to changes in environmental parameters, namely temperature, chlorophyll a and particulate organic carbon. Hence, temporal variability must be taken into account for the design of future biodiversity assessment studies, as different patterns may be observed depending on the sampling time. Associated epifaunal assemblages were consistently dominated by resident species (i.e. species present in all sampling periods) and a peak of rare species was observed in the transition from spring to summer following the increase of seawater temperature. Turnover was particularly high in the transition between the spring and summer periods. In both hosts, turnover was higher in the small sized colonies, which generally harboured less diverse and less abundant assemblages which also differed from those inhabiting larger size colonies. The high levels of diversity associated with gorgonian colonies highlights the need for the conservation of this priority habitat.

Temporal variability in epifaunal assemblages associated with temperate gorgonian gardens

KAUST Repository

Dias, I.M.

2015-10-19

The present study is one of the few that investigate the temporal variability of epifaunal assemblages associated with coral species, particularly the octocorals Eunicella gazella and Leptogorgia lusitanica in south Portugal. The results suggest time rather than colony size as a primary driver of the ecological patterns of these assemblages, which were dominated by amphipods, molluscs and polychaetes. Temporal variability was linked to changes in environmental parameters, namely temperature, chlorophyll a and particulate organic carbon. Hence, temporal variability must be taken into account for the design of future biodiversity assessment studies, as different patterns may be observed depending on the sampling time. Associated epifaunal assemblages were consistently dominated by resident species (i.e. species present in all sampling periods) and a peak of rare species was observed in the transition from spring to summer following the increase of seawater temperature. Turnover was particularly high in the transition between the spring and summer periods. In both hosts, turnover was higher in the small sized colonies, which generally harboured less diverse and less abundant assemblages which also differed from those inhabiting larger size colonies. The high levels of diversity associated with gorgonian colonies highlights the need for the conservation of this priority habitat.

Public transport travel time and its variability

OpenAIRE

Mazloumi Shomali, Ehsan

2017-01-01

Executive Summary Public transport agencies around the world are constantly trying to improve the performance of their service, and to provide passengers with a more reliable service. Two major measures to evaluate the performance of a transit system include travel time and travel time variability. Information on these two measures provides operators with a capacity to identify the problematic locations in a transport system and improve operating plans. Likewise, users can benefit through...

The MJO Transition from Shallow to Deep Convection in CloudSat/CALIPSO Data and GISS GCM Simulations

Science.gov (United States)

DelGenio, Anthony G.; Chen, Yonghua; Kim, Daehyun; Yao, Mao-Sung

2013-01-01

The relationship between convective penetration depth and tropospheric humidity is central to recent theories of the Madden-Julian oscillation (MJO). It has been suggested that general circulation models (GCMs) poorly simulate the MJO because they fail to gradually moisten the troposphere by shallow convection and simulate a slow transition to deep convection. CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data are analyzed to document the variability of convection depth and its relation to water vapor during the MJO transition from shallow to deep convection and to constrain GCM cumulus parameterizations. Composites of cloud occurrence for 10MJO events show the following anticipatedMJO cloud structure: shallow and congestus clouds in advance of the peak, deep clouds near the peak, and upper-level anvils after the peak. Cirrus clouds are also frequent in advance of the peak. The Advanced Microwave Scanning Radiometer for EarthObserving System (EOS) (AMSR-E) columnwater vapor (CWV) increases by;5 mmduring the shallow- deep transition phase, consistent with the idea of moisture preconditioning. Echo-top height of clouds rooted in the boundary layer increases sharply with CWV, with large variability in depth when CWV is between;46 and 68 mm. International Satellite Cloud Climatology Project cloud classifications reproduce these climatological relationships but correctly identify congestus-dominated scenes only about half the time. A version of the Goddard Institute for Space Studies Model E2 (GISS-E2) GCM with strengthened entrainment and rain evaporation that produces MJO-like variability also reproduces the shallow-deep convection transition, including the large variability of cloud-top height at intermediate CWV values. The variability is due to small grid-scale relative humidity and lapse rate anomalies for similar values of CWV. 1.

A high-peak-power passively Q-switched composite variable-cut vanadate laser

International Nuclear Information System (INIS)

Sirotkin, A A

2014-01-01

We present laser sources based on a novel method of controlling spectral parameters in diode-pumped vanadate lasers. Angular dependences of the luminescence intensity of Stark transitions at the 4F3/2‒4I11/2 transition in vanadate crystals are investigated. The operation of diode-pumped passively Q-switched composite variable-cut (θ = var, φ = 0) YVO 4 –Nd 3+  : YVO 4 lasers with Cr 4+  : YAG saturable absorber is demonstrated (the narrowest pulse of 2 ns with the highest peak power of 24.3 kW). In the experiment, an efficient self-Raman laser was realized, based on the multifunctional variable-cut (θ = 25°, φ = 0) YVO 4 –Nd 3+  : YVO 4 laser crystal with the passive Q-switched. (letters)

Relating Psychosocial Variables in High School to Alcohol Use Trajectories During the Transition to Young Adulthood

National Research Council Canada - National Science Library

Morrow, Craig

2000-01-01

.... This study examined psychosocial variables-including peer focus, social skills, affect, antisocial behavior, gender, and sex-role attitudes-in an attempt to uncover variables related to changes...

A multiple-field coupled resistive transition model for superconducting Nb3Sn

Directory of Open Access Journals (Sweden)

Lin Yang

2016-12-01

Full Text Available A study on the superconducting transition width as functions of the applied magnetic field and strain is performed in superconducting Nb3Sn. A quantitative, yet universal phenomenological resistivity model is proposed. The numerical simulation by the proposed model shows predicted resistive transition characteristics under variable magnetic fields and strain, which in good agreement with the experimental observations. Furthermore, a temperature-modulated magnetoresistance transition behavior in filamentary Nb3Sn conductors can also be well described by the given model. The multiple-field coupled resistive transition model is helpful for making objective determinations of the high-dimensional critical surface of Nb3Sn in the multi-parameter space, offering some preliminary information about the basic vortex-pinning mechanisms, and guiding the design of the quench protection system of Nb3Sn superconducting magnets.

Transitions of male partners of women with breast cancer: hope, guilt, and quality of life.

Science.gov (United States)

Duggleby, Wendy; Thomas, Jasmine; Montford, Kelly; Thomas, Roanne; Nekolaichuk, Cheryl; Ghosh, Sunita; Cumming, Ceiwen; Tonkin, Katia

2015-03-01

To (a) describe the types of transitions experienced by male spousal caregivers of women with breast cancer and the strategies used by male spouses to deal with these transitions and (b) examine factors related to their quality of life, including demographic variables, self-efficacy, caregiver guilt, hope, the quality of life of their partner with breast cancer, and transitions. Cross-sectional, transformational, mixed-methods approach. Participants' homes. 105 dyads of male spouses and their female partners diagnosed with stages I-III breast cancer. 600 surveys were mailed to women with breast cancer and their male partners. Significant variables were entered into a multivariate model. Male caregiver quality of life. The quality of life of male spouse participants was positively influenced by hope (p life scores reported higher hope and lower caregiver guilt scores. They reported lower quality-of-life scores if they dealt with transitions by "doing what needs to be done."
 Strategies to support male spouses of women with breast cancer should involve ways to foster hope, reduce feelings of guilt, and encourage male caregivers to engage more in supporting their spouses.

A Solvable Model for Nuclear Shape Phase Transitions

International Nuclear Information System (INIS)

Levai, G.; Arias, J. M.

2009-01-01

There has been considerable interest recently in phase transitions that occur between some well-defined nuclear shapes, e.g. the spherical vibrator, the axially deformed rotor and the γ-unstable rotor, which are assigned to the U(5), SU(3) and 0(6) symmetries. These shape phase transitions occur through critical points of the IBM phase diagram and correspond to rapid structural changes. The first transition of this type describes transition form the spherical to the γ-unstable phase and has been associated with an E(5) symmetry. Later further critical point symmetries e.g. X(5) and Y(5) have also been proposed for transitions between other nuclear shape phases. In another application the chain of even Ru isotopes was considered from A 98 to 112 [2]. The parameters were extracted from a fit to the low-lying energy spectrum of each nucleus and were used to plot the corresponding potential. It was found that up to A =102 the potential is essentially an harmonic oscillator, while at A =104 a rather flat potential was seen, in accordance with the expected phase transition and E(5) symmetry there. With increasing A then the minimum got increasingly deeper and moved away from β = 0. We discuss the possibility of generalizing the formalism in two ways: first by including dependence on the 7 variable allowing for the approximate description of nuclei close to the X(5) symmetry, and second, including higher-lying energy levels in the quasi-exactly solvable formalism

Transitional Justice

DEFF Research Database (Denmark)

Gissel, Line Engbo

This presentation builds on an earlier published article, 'Contemporary Transitional Justice: Normalising a Politics of Exception'. It argues that the field of transitional justice has undergone a shift in conceptualisation and hence practice. Transitional justice is presently understood to be th...... to be the provision of ordinary criminal justice in contexts of exceptional political transition.......This presentation builds on an earlier published article, 'Contemporary Transitional Justice: Normalising a Politics of Exception'. It argues that the field of transitional justice has undergone a shift in conceptualisation and hence practice. Transitional justice is presently understood...

Transition Services: An Investigation of the Knowledge, Confidence, and Practice of Special Education Teachers in District of Columbia Public Charter High Schools

Science.gov (United States)

Henry, Wallace R., III

2015-01-01

This study was intended to enhance the limited research on the knowledge and confidence of special education teachers in public education regarding transition services and the quality of transition plans they develop. The key variables examined in this study are knowledge, confidence, and the quality of student transition plans. The sample…

Generating feasible transition paths for testing from an extended finite state machine (EFSM) with the counter problem

OpenAIRE

Kalaji, AS; Hierons, RM; Swift, S

2009-01-01

The extended finite state machine (EFSM) is a powerful approach for modeling state-based systems. However, testing from EFSMs is complicated by the existence of infeasible paths. One important problem is the existence of a transition with a guard that references a counter variable whose value depends on previous transitions. The presence of such transitions in paths often leads to infeasible paths. This paper proposes a novel approach to bypass the counter problem. The proposed approach is ev...

UP-DOWN cortical dynamics reflect state transitions in a bistable network.

Science.gov (United States)

Jercog, Daniel; Roxin, Alex; Barthó, Peter; Luczak, Artur; Compte, Albert; de la Rocha, Jaime

2017-08-04

In the idling brain, neuronal circuits transition between periods of sustained firing (UP state) and quiescence (DOWN state), a pattern the mechanisms of which remain unclear. Here we analyzed spontaneous cortical population activity from anesthetized rats and found that UP and DOWN durations were highly variable and that population rates showed no significant decay during UP periods. We built a network rate model with excitatory (E) and inhibitory (I) populations exhibiting a novel bistable regime between a quiescent and an inhibition-stabilized state of arbitrarily low rate. Fluctuations triggered state transitions, while adaptation in E cells paradoxically caused a marginal decay of E-rate but a marked decay of I-rate in UP periods, a prediction that we validated experimentally. A spiking network implementation further predicted that DOWN-to-UP transitions must be caused by synchronous high-amplitude events. Our findings provide evidence of bistable cortical networks that exhibit non-rhythmic state transitions when the brain rests.

Phase Transition Behavior in a Neutral Evolution Model

Science.gov (United States)

King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

2014-03-01

The complexity of interactions among individuals and between individuals and the environment make agent based modeling ideal for studying emergent speciation. This is a dynamically complex problem that can be characterized via the critical behavior of a continuous phase transition. Concomitant with the main tenets of natural selection, we allow organisms to reproduce, mutate, and die within a neutral phenotype space. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (2013), even on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here we present another neutral model to investigate the `critical' phase transition behavior of three mating types - assortative, bacterial, and random - in a phenotype space as a function of the percentage of random death. Results show two types of phase transitions occurring for the parameters of the population size and the number of clusters (an analogue of species), indicating different evolutionary dynamics for system survival and clustering. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation.

Invariant molecular-dynamics approach to structural phase transitions

International Nuclear Information System (INIS)

Wentzcovitch, R.M.

1991-01-01

Two fictitious Lagrangians to be used in molecular-dynamics simulations with variable cell shape and suitable to study problems like structural phase transitions are introduced. Because they are invariant with respect to the choice of the simulation cell edges and eliminate symmetry breaking associated with the fictitious part of the dynamics, they improve the physical content of numerical simulations that up to now have been done by using Parrinello-Rahman dynamics

The Time Course of the Probability of Transition Into and Out of REM Sleep

Science.gov (United States)

Bassi, Alejandro; Vivaldi, Ennio A.; Ocampo-Garcés, Adrián

2009-01-01

Study Objectives: A model of rapid eye movement (REM) sleep expression is proposed that assumes underlying regulatory mechanisms operating as inhomogenous Poisson processes, the overt results of which are the transitions into and out of REM sleep. Design: Based on spontaneously occurring REM sleep episodes (“Episode”) and intervals without REM sleep (“Interval”), 3 variables are defined and evaluated over discrete 15-second epochs using a nonlinear logistic regression method: “Propensity” is the instantaneous rate of into-REM transition occurrence throughout an Interval, “Volatility” is the instantaneous rate of out-of-REM transition occurrence throughout an Episode, and “Opportunity” is the probability of being in non-REM (NREM) sleep at a given time throughout an Interval, a requisite for transition. Setting: 12:12 light:dark cycle, isolated boxes. Participants: Sixteen male Sprague-Dawley rats Interventions: None. Spontaneous sleep cycles. Measurements and Results: The highest levels of volatility and propensity occur, respectively, at the very beginning of Episodes and Intervals. The new condition stabilizes rapidly, and variables reach nadirs at minute 1.25 and 2.50, respectively. Afterward, volatility increases markedly, reaching values close to the initial level. Propensity increases moderately, the increment being stronger through NREM sleep bouts occurring at the end of long Intervals. Short-term homeostasis is evidenced by longer REM sleep episodes lowering propensity in the following Interval. Conclusions: The stabilization after transitions into Episodes or Intervals and the destabilization after remaining for some time in either condition may be described as resulting from continuous processes building up during Episodes and Intervals. These processes underlie the overt occurrence of transitions. Citation: Bassi A; Vivaldi EA; Ocampo-Garcées A. The time course of the probability of transition into and out of REM sleep. SLEEP 2009

A social-ecological model of readiness for transition to adult-oriented care for adolescents and young adults with chronic health conditions.

Science.gov (United States)

Schwartz, L A; Tuchman, L K; Hobbie, W L; Ginsberg, J P

2011-11-01

Policy and research related to transition to adult care for adolescents and young adults (AYAs) has focused primarily on patient age, disease skills and knowledge. In an effort to broaden conceptualization of transition and move beyond isolated patient variables, a new social-ecological model of AYA readiness for transition (SMART) was developed. SMART development was informed by related theories, literature, expert opinion and pilot data collection using a questionnaire developed to assess provider report of SMART components with 100 consecutive patients in a childhood cancer survivorship clinic. The literature, expert opinion and pilot data collection support the relevance of SMART components and a social-ecological conceptualization of transition. Provider report revealed that many components, representing more than age, disease knowledge and skills, related to provider plans for transferring patients. SMART consists of inter-related constructs of patients, parents and providers with emphasis on variables amenable to intervention. Results support SMART's broadened conceptualization of transition readiness and need for assessment of multiple stakeholders' perspectives of patient transition readiness. A companion measure of SMART, which will be able to be completed by patients, parents and providers, will be developed to target areas of intervention to facilitate optimal transition readiness. Similar research programmes to establish evidence-based transition measures and interventions are needed. © 2011 Blackwell Publishing Ltd.

DETAILED CHEMICAL KINETIC MODELING OF ISO-OCTANE SI-HCCI TRANSITION

Energy Technology Data Exchange (ETDEWEB)

Havstad, M A; Aceves, S M; McNenly, M J; Piggott, W T; Edwards, K D; Wagner, R M; Daw, C S; Finney, C A

2009-10-12

The authors describe a CHEMKIN-based multi-zone model that simulates the expected combustion variations in a single-cylinder engine fueled with iso-octane as the engine transitions from spark-ignited (ST) combustion to homogeneous charge compression ignition (HCCI) combustion. The model includes a 63-species reaction mechanism and mass and energy balances for the cylinder and the exhaust flow. For this study they assumed that the SI-to-HCCI transition is implemented by means of increasing the internal exhaust gas recirculation (EGR) at constant engine speed. This transition scneario is consistent with that implemented in previously reported experimental measurements on an experimental engine equipped with variable valve actuation. They find that the model captures many of the important experimental trends, including stable SI combustion at low EGR ({approx} 0.10), a transition to highly unstable combustion at intermediate EGR, and finally stable HCCI combustion at very high EGR ({approx} 0.75). Remaining differences between the predicted and experimental instability patterns indicate that there is further room for model improvement.

Effect of corruption on healthcare satisfaction in post-soviet nations: A cross-country instrumental variable analysis of twelve countries.

Science.gov (United States)

Habibov, Nazim

2016-03-01

There is the lack of consensus about the effect of corruption on healthcare satisfaction in transitional countries. Interpreting the burgeoning literature on this topic has proven difficult due to reverse causality and omitted variable bias. In this study, the effect of corruption on healthcare satisfaction is investigated in a set of 12 Post-Socialist countries using instrumental variable regression on the sample of 2010 Life in Transition survey (N = 8655). The results indicate that experiencing corruption significantly reduces healthcare satisfaction. Copyright © 2016 The Author. Published by Elsevier Ltd.. All rights reserved.

Variability in Glycemic Control with Temperature Transitions during Therapeutic Hypothermia

Directory of Open Access Journals (Sweden)

Krystal K. Haase

2017-01-01

Full Text Available Purpose. Patients treated with therapeutic hypothermia (TH and continuous insulin may be at increased risk of hyperglycemia or hypoglycemia, particularly during temperature transitions. This study aimed to evaluate frequency of glucose excursions during each phase of TH and to characterize glycemic control patterns in relation to survival. Methods. Patients admitted to a tertiary care hospital for circulatory arrest and treated with both therapeutic hypothermia and protocol-based continuous insulin between January 2010 and June 2013 were included. Glucose measures, insulin, and temperatures were collected through 24 hours after rewarming. Results. 24 of 26 patients experienced glycemic excursions. Hyperglycemic excursions were more frequent during initiation versus remaining phases (36.3%, 4.3%, 2.5%, and 4.0%, p=0.002. Hypoglycemia occurred most often during rewarming (0%, 7.7%, 23.1%, and 3.8%, p=0.02. Patients who experienced hypoglycemia had higher insulin doses prior to rewarming (16.2 versus 2.1 units/hr, p=0.03. Glucose variation was highest during hypothermia and trended higher in nonsurvivors compared to survivors (13.38 versus 9.16, p=0.09. Frequency of excursions was also higher in nonsurvivors (32.3% versus 19.8%, p=0.045. Conclusions. Glycemic excursions are common and occur more often in nonsurvivors. Excursions differ by phase but risk of hypoglycemia is increased during rewarming.

Population of computational rabbit-specific ventricular action potential models for investigating sources of variability in cellular repolarisation.

Directory of Open Access Journals (Sweden)

Philip Gemmell

Full Text Available Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K(+, inward rectifying K(+, L-type Ca(2+, and Na(+/K(+ pump currents in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al. at multiple cycle lengths (400, 600, 1,000 ms was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in

Population of computational rabbit-specific ventricular action potential models for investigating sources of variability in cellular repolarisation.

Science.gov (United States)

Gemmell, Philip; Burrage, Kevin; Rodriguez, Blanca; Quinn, T Alexander

2014-01-01

Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K(+), inward rectifying K(+), L-type Ca(2+), and Na(+)/K(+) pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally

Transition Features from Simplicity-Universality to Complexity-Diversification Under UHNTF

International Nuclear Information System (INIS)

Fang Jinqing; Li Yong

2010-01-01

A large unified hybrid network model with a variable speed growth (LUHNM-VSG) is proposed as third model of the unified hybrid network theoretical framework (UHNTF). A hybrid growth ratio vg of deterministic linking number to random linking number and variable speed growth index α are introduced in it. The main effects of vg and α on topological transition features of the LUHNM-VSG are revealed. For comparison with the other models, we construct a type of the network complexity pyramid with seven levels, in which from the bottom level-1 to the top level-7 of the pyramid simplicity-universality is increasing but complexity-diversity is decreasing. The transition relations between them depend on matching of four hybrid ratios (dr, fd, gr, vg). Thus the most of network models can be investigated in the unification way via four hybrid ratios (dr, fd, gr, vg). The LUHNM-VSG as the level-1 of the pyramid is much better and closer to description of real-world networks as well as has potential application. (interdisciplinary physics and related areas of science and technology)

Spatio-temporal evolution of the L → H and H → L transitions

International Nuclear Information System (INIS)

Miki, K.; Diamond, P.H.; Kosuga, Y.; Zhao, K.J.; Fedorczak, N.; Malkov, M.; Lee, C.; Tynan, G.; Gürcan, Ö.D.; Xu, G.S.; Estrada, T.; McDonald, D.; Schmitz, L.

2013-01-01

Understanding the L → H and H → L transitions is crucial to successful ITER operation. In this paper we present novel theoretical and modelling study results on the spatio-temporal dynamics of the transition. We place a special emphasis on the role of zonal flows and the micro → macro connection between dynamics and the power threshold (P T ) dependences. The model studied evolves five coupled fields in time and one space dimension, in simplified geometry. The content of this paper is (a) the model fundamentals and the space–time evolution during the L → I → H transition, (b) the physics origin of the well-known ∇B-drift asymmetry in P T , (c) the role of heat avalanches in the intrinsic variability of the L → H transition, (d) the dynamics of the H → L back transition and the physics of hysteresis, (e) conclusion and discussion, with a special emphasis on the implications of transition dynamics for the L → H power threshold scalings. (paper)

Magnetic and Structural Phase Transitions in Thulium under High Pressures and Low Temperatures

Energy Technology Data Exchange (ETDEWEB)

Vohra, Yogesh K.; Tsoi, Georgiy M.; Samudrala, Gopi K. [UAB

2017-10-01

The nature of 4f electrons in many rare earth metals and compounds may be broadly characterized as being either "localized" or "itinerant", and is held responsible for a wide range of physical and chemical properties. The pressure variable has a very dramatic effect on the electronic structure of rare earth metals which in turn drives a sequence of structural and magnetic transitions. We have carried out four-probe electrical resistance measurements on rare earth metal Thulium (Tm) under high pressures to 33 GPa and low temperatures to 10 K to monitor the magnetic ordering transition. These studies are complemented by angle dispersive x-ray diffraction studies to monitor crystallographic phase transitions at high pressures and low temperatures. We observe an abrupt increase in magnetic ordering temperature in Tm at a pressure of 17 GPa on phase transition from ambient pressure hcp-phase to α-Sm phase transition. In addition, measured equation of state (EOS) at low temperatures show anomalously low thermal expansion coefficients likely linked to magnetic transitions.

Study on State Transition Method Applied to Motion Planning for a Humanoid Robot

Directory of Open Access Journals (Sweden)

Xuyang Wang

2008-11-01

Full Text Available This paper presents an approach of motion planning for a humanoid robot using a state transition method. In this method, motion planning is simplified by introducing a state-space to describe the whole motion series. And each state in the state-space corresponds to a contact state specified during the motion. The continuous motion is represented by a sequence of discrete states. The concept of the transition between two neighboring states, that is the state transition, can be realized by using some traditional path planning methods. Considering the dynamical stability of the robot, a state transition method based on search strategy is proposed. Different sets of trajectories are generated by using a variable 5th-order polynomial interpolation method. After quantifying the stabilities of these trajectories, the trajectories with the largest stability margin are selected as the final state transition trajectories. Rising motion process is exemplified to validate the method and the simulation results show the proposed method to be feasible and effective.

Phase Transition between Black and Blue Phosphorenes: A Quantum Monte Carlo Study

Science.gov (United States)

Li, Lesheng; Yao, Yi; Reeves, Kyle; Kanai, Yosuke

Phase transition of the more common black phosphorene to blue phosphorene is of great interest because they are predicted to exhibit unique electronic and optical properties. However, these two phases are predicted to be separated by a rather large energy barrier. In this work, we study the transition pathway between black and blue phosphorenes by using the variable cell nudge elastic band method combined with density functional theory calculation. We show how diffusion quantum Monte Carlo method can be used for determining the energetics of the phase transition and demonstrate the use of two approaches for removing finite-size errors. Finally, we predict how applied stress can be used to control the energetic balance between these two different phases of phosphorene.

Transition from Hospital to Community Care: The Experience of Cancer Patients

Directory of Open Access Journals (Sweden)

Hanna Admi

2015-12-01

Full Text Available Purpose: This study examines care transition experiences of cancer patients and assesses barriers to effective transitions.Methods: Participants were adult Hebrew, Arabic, or Russian speaking oncology patients and health care providers from hospital and community settings. Qualitative (n=77 and quantitative (n=422 methods such as focus groups, interviews and self-administered questionnaires were used. Qualitative analysis showed that patients faced difficulties navigating a complex and fragmented healthcare system.Results: Mechanisms to overcome barriers included informal routes such as personal relationships, coordinating roles by nurse coordinators and the patients' general practitioners (GPs. The most significant variable was GPs involvement, which affected transition process quality as rated on the CTM (p<0.001. Our findings point to the important interpersonal role of oncology nurses to coordinate and facilitate the care transition process.Conclusion: Interventions targeted towards supporting the care transition process should emphasize ongoing counseling throughout a patient’s care, during and after hospitalization.-----------------------------------------Cite this article as:  Admi H, Muller E, Shadmi E. Transition from Hospital to Community Care: The Experience of Cancer Patients. Int J Cancer Ther Oncol 2015; 3(4:34011.[This abstract was presented at the BIT’s 8th Annual World Cancer Congress, which was held from May 15-17, 2015 in Beijing, China.

Transition Theory – Sustainable Transition of Socio-Technical Systems

DEFF Research Database (Denmark)

Søndergård, Bent; Holm, Jesper; Stauning, Inger

2015-01-01

Theories of transition management, transition studies and social practise theory Applied to studies of hosuing and construction......Theories of transition management, transition studies and social practise theory Applied to studies of hosuing and construction...

Synthesis and evaluation of MoWCoS/G and MoWCuS/G as new transition metal dichalcogenide nanocatalysts for electrochemical hydrogen evolution reaction

Science.gov (United States)

Askari, Mohammad Bagher; Beheshti-Marnani, Amirkhosro; Banizi, Zoha Tavakoli; Seifi, Majid; Ramezan zadeh, Mohammad Hassan

2018-01-01

New nanocomposites based on transition metal dichalcogenides, MoWCoS and MoWCuS, were synthesized through one step hydrothermal method. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques as well as field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the synthesis of nanocomposites. For investigation of hydrogen evolution reaction (HER) properties of new nanocomposites, linear sweep voltammetry (LSV) was applied for this purpose. According to the results of similar previous works, the prepared nanocomposites showed promising HER properties as low overpotential equal to 41.4 mV/dec for MoWCoS hybridized with reduced graphene (G) and a little higher one equal to 49 mV/dec for MoWCuS hybridized with reduced graphene. Based on obtained Tafel slopes 38 and 53 mV/dec for MoWCoS/G and MoWCuS/G, respectively, the "Heyrovsky-Volmer" mechanism was suggested for the new HER three component nanocatalysts as the first effort to this purpose.

Zodiacal Exoplanets in Time (ZEIT). V. A Uniform Search for Transiting Planets in Young Clusters Observed by K2

Science.gov (United States)

Rizzuto, Aaron C.; Mann, Andrew W.; Vanderburg, Andrew; Kraus, Adam L.; Covey, Kevin R.

2017-12-01

Detection of transiting exoplanets around young stars is more difficult than for older systems owing to increased stellar variability. Nine young open cluster planets have been found in the K2 data, but no single analysis pipeline identified all planets. We have developed a transit search pipeline for young stars that uses a transit-shaped notch and quadratic continuum in a 12 or 24 hr window to fit both the stellar variability and the presence of a transit. In addition, for the most rapid rotators ({P}{rot}Pleiades, Hyades, Praesepe) and conduct a uniform search of the members. We identify all known transiting exoplanets in the clusters, 17 eclipsing binaries, one transiting planet candidate orbiting a potential Pleiades member, and three orbiting unlikely members of the young clusters. Limited injection recovery testing on the known planet hosts indicates that for the older Praesepe systems we are sensitive to additional exoplanets as small as 1-2 R ⊕, and for the larger Upper Scorpius planet host (K2-33) our pipeline is sensitive to ˜4 R ⊕ transiting planets. The lack of detected multiple systems in the young clusters is consistent with the expected frequency from the original Kepler sample, within our detection limits. With a robust pipeline that detects all known planets in the young clusters, occurrence rate testing at young ages is now possible.

The Influence of School Policy and Practice on Mathematics Achievement During Transitional Periods

Directory of Open Access Journals (Sweden)

Janet K. Holt

2004-05-01

Full Text Available In this study, the effects of school policies and practices on math achievement growth, as students transitioned from middle to high school, were examined while controlling for school contextual variables. A pattern of accelerated growth in mathematics achievement from grades 8 to 12 occurred, in which higher achieving students in mathematics at grade eight accelerated more than lower achieving students in mathematics growth during the transition from middle to high school. Controlling for school context, school policy promoting parent involvement and academic counseling had significant positive impacts on the acceleration in growth during this period. The implications of using multilevel growth models to study growth during transition periods are discussed.

Mass transit ridership and self-reported hearing health in an urban population.

Science.gov (United States)

Gershon, Robyn R M; Sherman, Martin F; Magda, Lori A; Riley, Halley E; McAlexander, Tara P; Neitzel, Richard

2013-04-01

Information on prevalence and risk factors associated with self-reported hearing health among mass transit riders is extremely limited, even though evidence suggests mass transit may be a source of excessive exposure to noise. Data on mass transit ridership were collected from 756 study participants using a self-administered questionnaire. Hearing health was measured using two symptom items (tinnitus and temporary audiometric threshold shift), two subjective measures (self-rated hearing and hearing ability), and two medical-related questions (hearing testing and physician-diagnosed hearing loss). In logistic regression analyses that controlled for possible confounders, including demographic variables, occupational noise exposure, nonoccupational noise exposure (including MP3 player use) and use of hearing protection, frequent and lengthy mass transit (all forms) ridership (1,100 min or more per week vs. 350 min or less per week) was the strongest predictor of temporary threshold shift symptoms. Noise abatement strategies, such as engineering controls, and the promotion of hearing protection use should be encouraged to reduce the risk of adverse impacts on the hearing health of mass transit users.

Influence of longitudinal spin fluctuations on the phase transition features in chiral magnets

Science.gov (United States)

Belemuk, A. M.; Stishov, S. M.

2018-04-01

Using the classical Monte Carlo calculations, we investigate the effects of longitudinal spin fluctuations on the helimagnetic transition in a Heisenberg magnet with the Dzyaloshinskii-Moriya interaction. We use variable spin amplitudes in the framework of the spin-lattice Hamiltonian. It is this kind of fluctuations that naturally occur in an itinerant system. We show that the basic features of the helical phase transition are not changed much by the longitudinal spin fluctuations though the transition temperature Tc and the fluctuation hump seen in specific heat at T >Tc is significantly affected. We report thermodynamic and structural effects of these fluctuations. By increasing the system size in the Monte Carlo modeling, we are able to reproduce the ring shape scattering intensity above the helimagnetic transition temperature Tc, which transforms into the spiral spots seen below Tc in the neutron scattering experiments.

Characterization of Nighttime Light Variability Over the Southeastern United States

Science.gov (United States)

Cole, Tony A.; Molthan, Andrew L.; Schultz, Lori A.

2016-01-01

City lights provide indications of human activity at night. Nighttime satellite imagery offers daily snapshots of this activity. With calibrated, science-quality imagery, long-term monitoring can also be achieved. The degree to which city lights fluctuate, however, is not well known. For the application of detecting power outages, this degree of variability is crucial for assessing reductions to city lights based on historical trends. Eight southeastern U.S. cities are analyzed to understand the relationship between emission variability and several population centers. A preliminary, example case power outage study is also discussed as a transition into future work.

Strain engineering of topological phase transition in elemental gray tin: Dirac semimetal phase in the missing half of strain spectrum

Science.gov (United States)

Huang, Huaqing; Liu, Feng

Gray tin was previously found to be a strong topological insulator under compressive uniaxial strain. Here, based on effective k . p analysis and first-principles calculations, we discover that gray tin becomes a Dirac semimetal in the other missing half of strain spectrum, under tensile uniaxial strain. In this newly found Dirac semimetal state, two Dirac points which are tunable by tensile [001] strains, lie in the kz axis and Fermi arcs appear in the (100) surface. A large negative magnetoresistance is anticipated in this half of strain spectrum, which shows as a strong signature of the chiral anomaly effect. Comparing to other Dirac semimetal materials, the proposed Dirac semimetal state in the nontoxic elemental gray tin can be more easily manipulated and accurately controlled. We envision that gray tin provides a perfect platform for strain engineering of topological phase transitions by sweeping through the strain spectrum from positive to negative and vice versa. This work was support by DOE-BES (Grant No. DE-FG02-04ER46148).

A Switchable Molecular Dielectric with Two Sequential Reversible Phase Transitions: [(CH3)4P]4[Mn(SCN)6].

Science.gov (United States)

Li, Qiang; Shi, Ping-Ping; Ye, Qiong; Wang, Hui-Ting; Wu, De-Hong; Ye, Heng-Yun; Fu, Da-Wei; Zhang, Yi

2015-11-16

A new organic-inorganic hybrid switchable and tunable dielectric compound, [(CH3)4P]4[Mn(SCN)6] (1), exhibits three distinct dielectric states above room temperature and undergoes two reversible solid-state phase transitions, including a structural phase transition at 330 K and a ferroelastic phase transition with the Aizu notation of mmmF2/m at 352 K. The variable-temperature structural analyses disclose that the origin of the phase transitions and dielectric anomalies can be ascribed to the reorientation or motion of both the [(CH3)4P](+) cations and [Mn(SCN)6](4-) anions in solid-state crystals.

Planetary transit candidates in the CoRoT-SRc01 field

DEFF Research Database (Denmark)

Erikson, A.; Santerne, A.; Renner, S.

2012-01-01

Context. CoRoT is a pioneering space mission whose primary goals are stellar seismology and extrasolar planets search. Its surveys of large stellar fields generate numerous planetary candidates whose lightcurves have transit-like features. An extensive analytical and observational follow-up effort...... is undertaken to classify these candidates. Aims. We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008. Methods. We acquired...... and analyzed 7470 chromatic and 3938 monochromatic lightcurves. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves. Results. Fifty-one stars were classified...

Understanding Transitions Toward Sustainable Urban Water Management: Miami, Las Vegas, Los Angeles

Science.gov (United States)

Garcia, M. E.; Manago, K. F.; Treuer, G.; Deslatte, A.; Koebele, E.; Ernst, K.

2016-12-01

Cities in the United States face numerous threats to their long-term water supplies including preserving ecosystems, competing uses, and climate change. Yet, it is unclear why only some cities have transitioned toward more sustainable water management. These transitions include strategies such as water conservation, water supply portfolio diversification, long-term planning, and integrated resource management. While the circumstances that motivate or moderate transition may vary greatly across cities' physical and institutional contexts, identifying common factors associated with transition can help resource managers capitalize on windows of opportunity for change. To begin the process of identifying such factors, we ask two questions: 1) what combinations of conditions are associated with water management transitions?, and 2) what are the outcomes of these transitions? We examine three cases of utility-level water management in Miami, Las Vegas, and Los Angeles to create data-driven narratives detailing each city's transition. These narratives systematically synthesize multiple data sources to enable cross-case comparison and provide insights into how and why cities transition. Using the foundational concepts from the exposure-based theory of urban change, we focus our analysis on three broad categories of variables that influence urban water management transition: biophysical, political, and regulatory exposures. First, we compare these factors across time and across cities using metrics that standardize diverse data sources. Next, we incorporate qualitative factors that capture a city's unique conditions by integrating these metrics with salient contextual information. Then, through cross-city comparison, we identify factors associated with transition.

The Politics of Human Rights in Argentina

OpenAIRE

Brysk, Alison

2013-01-01

Revised edition of 1994 out-of-print Stanford University Press study of human rights protest, social change, and democratization in Argentina.  A symbolic politics analysis of the truth commission, trials, and policy reform in Latin America's most sweeping transition of the 1980's.

Plasma magnetic field measurement by intracavity absorption. Progress report, June 1, 1983-May 31, 1984

International Nuclear Information System (INIS)

Brink, G.O.

1984-01-01

Dye laser intracavity absorption (ICA) is being studied as a potential diagnostic for plasma or neutral beam systems. For magnetic field measurements it is necessary to make Zeeman effect measurements on the resonance transition of atomic lithium on a millisecond time scale. To do this it is necessary to sweep the dye laser in wavelength at a rapid rate so that the absorber can be sampled many times during the measurement. Our results indicate that the ICA signal becomes small at high sweep rates limiting the rate at which such sweeping may be carried out. It may be possible to avoid this limitation by chopping the pump laser. The studies of coupled cavity ICA are continuing, and are discussed in detail in an appendix. An ICA system using a dye cell has been designed, and supplementary experiments involving the observation of ICA in a ring dye laser are discussed

Phase transition transistors based on strongly-correlated materials

Science.gov (United States)

Nakano, Masaki

2013-03-01

The field-effect transistor (FET) provides electrical switching functions through linear control of the number of charges at a channel surface by external voltage. Controlling electronic phases of condensed matters in a FET geometry has long been a central issue of physical science. In particular, FET based on a strongly correlated material, namely ``Mott transistor,'' has attracted considerable interest, because it potentially provides gigantic and diverse electronic responses due to a strong interplay between charge, spin, orbital and lattice. We have investigated electric-field effects on such materials aiming at novel physical phenomena and electronic functions originating from strong correlation effects. Here we demonstrate electrical switching of bulk state of matter over the first-order metal-insulator transition. We fabricated FETs based on VO2 with use of a recently developed electric-double-layer transistor technique, and found that the electrostatically induced carriers at a channel surface drive all preexisting localized carriers of 1022 cm-3 even inside a bulk to motion, leading to bulk carrier delocalization beyond the electrostatic screening length. This non-local switching of bulk phases is achieved with just around 1 V, and moreover, a novel non-volatile memory like character emerges in a voltage-sweep measurement. These observations are apparently distinct from those of conventional FETs based on band insulators, capturing the essential feature of collective interactions in strongly correlated materials. This work was done in collaboration with K. Shibuya, D. Okuyama, T. Hatano, S. Ono, M. Kawasaki, Y. Iwasa, and Y. Tokura. This work was supported by the Japan Society for the Promotion of Science (JSAP) through its ``Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).''

Validation of a RANS transition model using a high-order weighted compact nonlinear scheme

Science.gov (United States)

Tu, GuoHua; Deng, XiaoGang; Mao, MeiLiang

2013-04-01

A modified transition model is given based on the shear stress transport (SST) turbulence model and an intermittency transport equation. The energy gradient term in the original model is replaced by flow strain rate to saving computational costs. The model employs local variables only, and then it can be conveniently implemented in modern computational fluid dynamics codes. The fifth-order weighted compact nonlinear scheme and the fourth-order staggered scheme are applied to discrete the governing equations for the purpose of minimizing discretization errors, so as to mitigate the confusion between numerical errors and transition model errors. The high-order package is compared with a second-order TVD method on simulating the transitional flow of a flat plate. Numerical results indicate that the high-order package give better grid convergence property than that of the second-order method. Validation of the transition model is performed for transitional flows ranging from low speed to hypersonic speed.

Influence of the variable thermophysical properties on the turbulent buoyancy-driven airflow inside open square cavities

Science.gov (United States)

Zamora, Blas; Kaiser, Antonio S.

2012-01-01

The effects of the air variable properties (density, viscosity and thermal conductivity) on the buoyancy-driven flows established in open square cavities are investigated, as well as the influence of the stated boundary conditions at open edges and the employed differencing scheme. Two-dimensional, laminar, transitional and turbulent simulations are obtained, considering both uniform wall temperature and uniform heat flux heating conditions. In transitional and turbulent cases, the low-Reynolds k - ω turbulence model is employed. The average Nusselt number and the dimensionless mass-flow rate have been obtained for a wide and not yet covered range of the Rayleigh number varying from 103 to 1016. The results obtained taking into account variable properties effects are compared with those calculated assuming constant properties and the Boussinesq approximation. For uniform heat flux heating, a correlation for the critical heating parameter above which the burnout phenomenon can be obtained is presented, not reported in previous works. The effects of variable properties on the flow patterns are analyzed.

THE LUPUS TRANSIT SURVEY FOR HOT JUPITERS: RESULTS AND LESSONS

International Nuclear Information System (INIS)

Bayliss, Daniel D. R.; Sackett, Penny D.; Weldrake, David T. F.; Tingley, Brandon W.; Lewis, Karen M.

2009-01-01

We present the results of a deep, wide-field transit survey targeting 'Hot Jupiter' planets in the Lupus region of the Galactic plane conducted over 53 nights concentrated in two epochs separated by a year. Using the Australian National University 40-inch telescope at Siding Spring Observatory (SSO), the survey covered a 0.66 deg 2 region close to the Galactic plane (b = 11 0 ) and monitored a total of 110,372 stars (15.0 ≤ V ≤ 22.0). Using difference imaging photometry, 16,134 light curves with a photometric precision of σ < 0.025 mag were obtained. These light curves were searched for transits, and four candidates were detected that displayed low-amplitude variability consistent with a transiting giant planet. Further investigations, including spectral typing and radial velocity measurements for some candidates, revealed that of the four, one is a true planetary companion (Lupus-TR-3), two are blended systems (Lupus-TR-1 and 4), and one is a binary (Lupus-TR-2). The results of this successful survey are instructive for optimizing the observational strategy and follow-up procedure for deep searches for transiting planets, including an upcoming survey using the SkyMapper telescope at SSO.

Method of collective variables with reference system for the grand canonical ensemble

International Nuclear Information System (INIS)

Yukhnovskii, I.R.

1989-01-01

A method of collective variables with special reference system for the grand canonical ensemble is presented. An explicit form is obtained for the basis sixth-degree measure density needed to describe the liquid-gas phase transition. Here the author presents the fundamentals of the method, which are as follows: (1) the functional form for the partition function in the grand canonical ensemble; (2) derivation of thermodynamic relations for the coefficients of the Jacobian; (3) transition to the problem on an adequate lattice; and (4) obtaining of the explicit form for the functional of the partition function

Ternary scandium and transition metals germanides

International Nuclear Information System (INIS)

Kotur, B.Ya.

1992-01-01

Brief review of data on phase diagram of ternary Sc-Me-Ge systems (Me-d - , f-transition element) is given. Isothermal sections at 870 and 1070 K of 17 ternary systems are plotted. Compositions and their structural characteristics are presented. Variability of crystal structure is typical for ternary scandium germanides: 70 compounds with the studied structure belong to 23 structural types. Ternary germanides isostructural to types of Sm 4 Ge 4 , ZrCrSi 2 , ZrNiAl, ScCeSi, TiNiSi U 4 Re 7 Si 6 145 compounds from 70 under investigation are mostly formed in studied systems

INSTITUTIONAL DETERMINANTS OF INVESTMENT INFLOWS INTO TRANSITION ECONOMIES

Directory of Open Access Journals (Sweden)

Donu Victoria

2015-12-01

Full Text Available This article investigates the relationship between institutional quality and the level of investment inflows into post-communist countries. We attempt to empirically verify the argument that institutional determinants are essential in explaining the variation in investment inflows into transition economies after the demise of socialism in the early 1990s. The role of institutions is assessed using Economic Freedom indices provided by the Heritage Foundation. Consequently, to investigate the progress of institutional quality in transition economies, we further employ indicators developed by the European Bank for Reconstruction and Development. Using a panel data set for 11 transition countries from 1993 to 2013, we conclude that the impact of institutional quality on investment inflows is not negligible, yet much weaker than suggested by the existing theoretical literature. Using a  fixed-effects model framework in both regression benchmarks with metrics from the Heritage Foundation and the European Bank for Reconstruction and Development, respectively, we observe that the impact of institutional variables on the level of investment was less significant than expected. Moreover, macroeconomic fundamentals appear to always play a more substantial role than institutional factors.

A precursor to the Matuyama/Brunhes transition-field instability as recorded in pelagic sediments

NARCIS (Netherlands)

Hartla, Paul; Tauxe, Lisa

1995-01-01

The period some 20-25 kyr just prior to the most recent generally recognized geomagnetic field polarity transition, the Matuyama-to-Brunhes reversal, appears to be marked by significant geomagnetic variability, manifested as pronounced oscillations in intensity. We compare several previously

A Transient Transit Signature Associated with the Young Star RIK-210

Energy Technology Data Exchange (ETDEWEB)

David, Trevor J.; Hillenbrand, Lynne A.; Howard, Andrew W.; Wang, Ji [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Petigura, Erik A.; Benneke, Björn [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie; Howell, Steve B. [NASA Ames Research Center, Mountain View, California 94035 (United States); Cameron, Andrew Collier [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS (United Kingdom); Stauffer, John R. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Fulton, B. J. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Isaacson, Howard T. [Department of Astronomy, University of California, Berkeley, California 94720 (United States); Everett, Mark E. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Hellier, Coel; Anderson, David R. [Astrophysics Group, Keele University, Staffordshire, ST5 5BG (United Kingdom); West, Richard G.; Pollacco, Don, E-mail: tjd@astro.caltech.edu [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

2017-02-01

We find transient transit-like dimming events within the K2 time series photometry of the young star RIK-210 in the Upper Scorpius OB association. These dimming events are variable in depth, duration, and morphology. High spatial resolution imaging revealed that the star is single and radial velocity monitoring indicated that the dimming events cannot be due to an eclipsing stellar or brown dwarf companion. Archival and follow-up photometry suggest the dimming events are transient in nature. The variable morphology of the dimming events suggests they are not due to a single spherical body. The ingress of each dimming event is always shallower than egress, as one would expect for an orbiting body with a leading tail. The dimming events are periodic and synchronous with the stellar rotation. However, we argue it is unlikely the dimming events could be attributed to anything on the stellar surface based on the observed depths and durations. Variable obscuration by a protoplanetary disk is unlikely on the basis that the star is not actively accreting and lacks the infrared excess associated with an inner disk. Rather, we explore the possibilities that the dimming events are due to magnetospheric clouds, a transiting protoplanet surrounded by circumplanetary dust and debris, eccentric orbiting bodies undergoing periodic tidal disruption, or an extended field of dust or debris near the corotation radius.

On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

Science.gov (United States)

Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

2003-03-01

This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

Mortality-fertility synergies during the demographic transition in the developed world.

Science.gov (United States)

Sánchez-Barricarte, Jesús J

2017-07-01

The classic theory used to explain the demographic transition assumes that mortality is the key explanatory variable influencing the decline in fertility. However, the empirical results obtained in what is known as the Princeton European Fertility Project have led many specialists to question this assumption. Using both national and provincial aggregated data for 25 countries over a long time span, the analysis reported in this paper found that mortality does indeed play a fundamental role in accounting for the main demographic changes that occurred both before and during the transitional period. Others' research based on individual data has shown clearly that the number of surviving children was indeed an important factor for reproductive decisions. My analysis, using aggregated data, reached largely similar conclusions regarding the role of mortality in changing reproductive trends, via its impact on nuptiality and marital fertility at different stages of the demographic transition.

Phase transitions in single macromolecules: Loop-stretch transition versus loop adsorption transition in end-grafted polymer chains

Science.gov (United States)

Zhang, Shuangshuang; Qi, Shuanhu; Klushin, Leonid I.; Skvortsov, Alexander M.; Yan, Dadong; Schmid, Friederike

2018-01-01

We use Brownian dynamics simulations and analytical theory to compare two prominent types of single molecule transitions. One is the adsorption transition of a loop (a chain with two ends bound to an attractive substrate) driven by an attraction parameter ɛ and the other is the loop-stretch transition in a chain with one end attached to a repulsive substrate, driven by an external end-force F applied to the free end. Specifically, we compare the behavior of the respective order parameters of the transitions, i.e., the mean number of surface contacts in the case of the adsorption transition and the mean position of the chain end in the case of the loop-stretch transition. Close to the transition points, both the static behavior and the dynamic behavior of chains with different length N are very well described by a scaling ansatz with the scaling parameters (ɛ - ɛ*)Nϕ (adsorption transition) and (F - F*)Nν (loop-stretch transition), respectively, where ϕ is the crossover exponent of the adsorption transition and ν is the Flory exponent. We show that both the loop-stretch and the loop adsorption transitions provide an exceptional opportunity to construct explicit analytical expressions for the crossover functions which perfectly describe all simulation results on static properties in the finite-size scaling regime. Explicit crossover functions are based on the ansatz for the analytical form of the order parameter distributions at the respective transition points. In contrast to the close similarity in equilibrium static behavior, the dynamic relaxation at the two transitions shows qualitative differences, especially in the strongly ordered regimes. This is attributed to the fact that the surface contact dynamics in a strongly adsorbed chain is governed by local processes, whereas the end height relaxation of a strongly stretched chain involves the full spectrum of Rouse modes.

Aql X-1 transition towards the soft (banana) state accompanied by radio/NIR detection

Science.gov (United States)

Sivakoff, G. R.; Miller-Jones, J.; Fox, O.; Linares, M.; Altamirano, D.; Russell, D.

2009-11-01

The currently active neutron star transient and atoll source Aql X-1 (Linares et al., ATEL #2288) has begun the transition from the hard (extreme island) state to the soft (banana) state (Rodriguez et al. ATEL #2299). This transition likely began around 2009 Nov 15 (MJD = 55150). The latest RXTE PCA observation (2009 Nov 17, MJD=55152.17+/-0.02, 2-60 keV fractional rms variability amplitude of ~11% for 0.1-10 Hz) indicates that the source is in the intermediate (island) state.

Quantum phase transitions

International Nuclear Information System (INIS)

Sachdev, S.

1999-01-01

Phase transitions are normally associated with changes of temperature but a new type of transition - caused by quantum fluctuations near absolute zero - is possible, and can tell us more about the properties of a wide range of systems in condensed-matter physics. Nature abounds with phase transitions. The boiling and freezing of water are everyday examples of phase transitions, as are more exotic processes such as superconductivity and superfluidity. The universe itself is thought to have passed through several phase transitions as the high-temperature plasma formed by the big bang cooled to form the world as we know it today. Phase transitions are traditionally classified as first or second order. In first-order transitions the two phases co-exist at the transition temperature - e.g. ice and water at 0 deg., or water and steam at 100 deg. In second-order transitions the two phases do not co-exist. In the last decade, attention has focused on phase transitions that are qualitatively different from the examples noted above: these are quantum phase transitions and they occur only at the absolute zero of temperature. The transition takes place at the ''quantum critical'' value of some other parameter such as pressure, composition or magnetic field strength. A quantum phase transition takes place when co-operative ordering of the system disappears, but this loss of order is driven solely by the quantum fluctuations demanded by Heisenberg's uncertainty principle. The physical properties of these quantum fluctuations are quite distinct from those of the thermal fluctuations responsible for traditional, finite-temperature phase transitions. In particular, the quantum system is described by a complex-valued wavefunction, and the dynamics of its phase near the quantum critical point requires novel theories that have no analogue in the traditional framework of phase transitions. In this article the author describes the history of quantum phase transitions. (UK)

Storage of Quantum Variables in Atomic Media

DEFF Research Database (Denmark)

Cviklinski, J.; Ortalo, J.; Josse, V.

2007-01-01

Storage and read-out of non classical states of light is a critical element for quantum information networks. Simultaneous storage of two non-commuting variables carried by light and subsequent read-out is shown to be possible in atomic ensembles. Interaction of light fields with three-level syst......-level systems allows direct mapping the quantum state of light into long lived coherences in the atomic ground state. We show that excess noise linked to atomic transitions can be made negligible. Experimental developments are discussed for atomic vapours and cold atoms....

Critical system issues and modeling requirements - the problem of beam energy sweep in an electron linear induction accelerator

International Nuclear Information System (INIS)

Turner, W.C.; Barrett, D.M.; Sampayan, S.E.

1991-01-01

In this paper the authors attempt to motivate the development of modeling tools for linear induction accelerator components by giving examples of performance limitations related to energy sweep. The most pressing issues is the development of an accurate model of the switching behavior of large magnetic cores at high dB/dt in the accelerator and magnetic compression modulators. Ideally one would like to have a model with as few parameters as possible that allows the user to choose the core geometry and magnetic material and perhaps a few parameters characterizing the switch model. Beyond this, the critical modeling tasks are: simulation of a magnetic compression modulator, modeling the reset dynamics of a magnetic compression modulator, modeling the loading characteristics of a linear induction accelerator cell, and modeling the electron injector current including the dynamics of feedback modulation and beam loading in an accelerator cell. Of course in the development of these models care should be given to benchmarking them against data from experimental systems. Beyond that one should aim for tools that have predictive power so that they can be used as design tools and not merely to replicate existing data

A Compact Two-Stage 120 W GaN High Power Amplifier for SweepSAR Radar Systems

Science.gov (United States)

Thrivikraman, Tushar; Horst, Stephen; Price, Douglas; Hoffman, James; Veilleux, Louise

2014-01-01

This work presents the design and measured results of a fully integrated switched power two-stage GaN HEMT high-power amplifier (HPA) achieving 60% power-added efficiency at over 120Woutput power. This high-efficiency GaN HEMT HPA is an enabling technology for L-band SweepSAR interferometric instruments that enable frequent repeat intervals and high-resolution imagery. The L-band HPA was designed using space-qualified state-of-the-art GaN HEMT technology. The amplifier exhibits over 34 dB of power gain at 51 dBm of output power across an 80 MHz bandwidth. The HPA is divided into two stages, an 8 W driver stage and 120 W output stage. The amplifier is designed for pulsed operation, with a high-speed DC drain switch operating at the pulsed-repetition interval and settles within 200 ns. In addition to the electrical design, a thermally optimized package was designed, that allows for direct thermal radiation to maintain low-junction temperatures for the GaN parts maximizing long-term reliability. Lastly, real radar waveforms are characterized and analysis of amplitude and phase stability over temperature demonstrate ultra-stable operation over temperature using integrated bias compensation circuitry allowing less than 0.2 dB amplitude variation and 2 deg phase variation over a 70 C range.

Transient nature of late Pleistocene climate variability.

Science.gov (United States)

Crowley, Thomas J; Hyde, William T

2008-11-13

Climate in the early Pleistocene varied with a period of 41 kyr and was related to variations in Earth's obliquity. About 900 kyr ago, variability increased and oscillated primarily at a period of approximately 100 kyr, suggesting that the link was then with the eccentricity of Earth's orbit. This transition has often been attributed to a nonlinear response to small changes in external boundary conditions. Here we propose that increasing variablility within the past million years may indicate that the climate system was approaching a second climate bifurcation point, after which it would transition again to a new stable state characterized by permanent mid-latitude Northern Hemisphere glaciation. From this perspective the past million years can be viewed as a transient interval in the evolution of Earth's climate. We support our hypothesis using a coupled energy-balance/ice-sheet model, which furthermore predicts that the future transition would involve a large expansion of the Eurasian ice sheet. The process responsible for the abrupt change seems to be the albedo discontinuity at the snow-ice edge. The best-fit model run, which explains almost 60% of the variance in global ice volume during the past 400 kyr, predicts a rapid transition in the geologically near future to the proposed glacial state. Should it be attained, this state would be more 'symmetric' than the present climate, with comparable areas of ice/sea-ice cover in each hemisphere, and would represent the culmination of 50 million years of evolution from bipolar nonglacial climates to bipolar glacial climates.

The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer

Energy Technology Data Exchange (ETDEWEB)

Agol, E.; /Washington U., Seattle, Astron. Dept. /Santa Barbara, KITP /UC, Santa Barbara; Cowan, Nicolas B.; /Washington U., Seattle, Astron. Dept.; Knutson, Heather A.; /UC, Berkeley, Astron. Dept.; Deming, Drake; /NASA, Goddard; Steffen, Jason H.; /Fermilab; Henry, Gregory W.; /Tennessee State U.; Charbonneau, David; /Harvard-Smithsonian Ctr. Astrophys.

2010-07-01

We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope IRAC camera at 8 microns, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector 'ramp' variation with a double-exponential function which performs better and is a better physical model for this detector variation. Our main scientific findings are: (1) an upper limit on the variability of the day-side planet flux of 2.7% (68% confidence); (2) the most precise set of transit times measured for a transiting planet, with an average accuracy of 3 seconds; (3) a lack of transit-timing variations, excluding the presence of second planets in this system above 20% of the mass of Mars in low-order mean-motion resonance at 95% confidence; (4) a confirmation of the planet's phase variation, finding the night side is 64% as bright as the day side, as well as an upper limit on the night-side variability of 17% (68% confidence); (5) a better correction for stellar variability at 8 micron causing the phase function to peak 3.5 hours before secondary eclipse, confirming that the advection and radiation timescales are comparable at the 8 micron photosphere; (6) variation in the depth of transit, which possibly implies variations in the surface brightness of the portion of the star occulted by the planet, posing a fundamental limit on non-simultaneous multi-wavelength transit absorption measurements of planet atmospheres; (7) a measurement of the infrared limb-darkening of the star, which is in good agreement with stellar atmosphere models; (8) an offset in the times of secondary eclipse of 69 seconds, which is mostly accounted for by a 31 second light travel time delay and 33 second delay due to the shift of ingress and egress by the planet hot spot; this confirms that the phase variation is due to an offset hot

Performance of healthcare organizations: contributing variables to efficiency and quality

OpenAIRE

Albuquerque, Isabel Garcia da Fonseca e Faro de

2018-01-01

The transition from volume-based healthcare to value-based healthcare has been the major challenge of National Health Systems. Nevertheless, some variables that might contribute to bring together healthcare professionals and healthcare challenges have been overlooked. Study A, the first of three studies, conducted in a primary healthcare setting, revealed that perceived and objective organizational performance is predicted by sense of community, which simultaneously mediates the relationship ...

Effects of variable sticking coefficients on the stability of reactive sputtering process

International Nuclear Information System (INIS)

Li Chuan; Hsieh Janghsing

2004-01-01

In reactive sputtering, the introduction of a reactive gas can lead to a hysteresis transition from metal to compounds in both the target and substrate. The hysteresis transition is characterized by a sudden change in partial pressure, sputtering rate, fraction of compound formation, etc. Therefore, stability is an important issue in the process control. In this paper, a mathematical model with variable sticking coefficients based on surface kinetics is used to study the stability of the process. The variable sticking coefficient represents different mechanisms for surface reactions from the Langmuir to precursor type. In order to facilitate the analysis, several nondimensional parameters are identified and used for formulation. Results show that an unsteady system converges to a steady state relatively fast at low inflow rates. With an eigenvalue analysis, the range of positive eigenvalues is consistent with the presence of a hysteresis loop. It is also found that when the chemical reaction on the substrate is moderate, a higher sputter yield of the compound leads to a more stable steady state at lower inflow rates. Regarding the sticking mechanism, for the type of precursors with the parameter k < 1, the compound is easier to form and saturate on the surface due to the higher default sticking coefficient and the lower operating conditions for the hysteresis transition

Studies of electron transitions using solid He pressure techniques

International Nuclear Information System (INIS)

Schirber, J.E.

1977-01-01

Changes in the topology of the Fermi surfaces of metals occur with variation of temperature or stoichiometry in a number of metallic systems of current interest. Pressure generated by a variety of techniques has proven to be the most useful experimental variable in the study of these transitions, but in most cases only solid He techniques yield sufficiently hydrostatic conditions to permit direct measurements of the Fermi surface as a function of pressure

Transition over C4 leading edge and measurement of intermittency factor using PDF of hot-wire signal

Energy Technology Data Exchange (ETDEWEB)

Hazarika, B.K.; Hirsch, C. [Vrije Univ. Brussel, Brussels (Belgium). Dept. of Fluid Mechanics

1997-07-01

The variation of intermittency factors in the transition region of a C4 leading edge flat plate is measured at three incidence angles in a low-turbulence free stream. During the determination of intermittency factor, the threshold value of the detector function and the validity of conditional averaging are verified by a method based on the direct application of PDF of the hot-wire output. As the angle of incidence is increased, the transition progressively moves through all the three modes on the suction surface: at zero incidence the bypass transition, at 2 deg incidence the natural transition, and at 4 deg incidence the separated-flow transition occur, respectively. All three modes of transition exhibited the chordwise intermittency factor variation in accordance with Narasinha`s universal intermittency distribution; thus, the method based on spot production rate is applicable to all the three modes of transition. In the transition zone of the attached boundary layers, the conditionally averaged interturbulent profiles are fuller than the Blasius profile, while the conditionally averaged turbulent profiles follow a logarithmic profile with a variable additive parameter.

Assessment of Tandem Measurements of pH and Total Gut Transit Time in Healthy Volunteers

OpenAIRE

Mikolajczyk, Adam E; Watson, Sydeaka; Surma, Bonnie L; Rubin, David T

2015-01-01

Objectives: The variation of luminal pH and transit time in an individual is unknown, yet is necessary to interpret single measurements. This study aimed to assess the intrasubject variability of gut pH and transit time in healthy volunteers using SmartPill devices (Covidien, Minneapolis, MN). Methods: Each subject (n=10) ingested two SmartPill devices separated by 24?h. Mean pH values were calculated for 30?min after gastric emptying (AGE), before the ileocecal (BIC) valve, after the ileocec...

Hybrid Electric Transit Bus

Science.gov (United States)

Viterna, Larry A.

1997-01-01

A government, industry, and university cooperative is developing an advanced hybrid electric city transit bus. Goals of this effort include doubling the fuel economy compared to current buses and reducing emissions to one-tenth of current EPA standards. Unique aspects of the vehicle's power system include the use of ultra-capacitors as an energy storage system, and a planned natural gas fueled turbogenerator developed from a small jet engine. Power from both the generator and energy storage system is provided to a variable speed electric motor attached to the rear axle. At over 15000 kg gross weight, this is the largest vehicle of its kind ever built using ultra-capacitor energy storage. This paper describes the overall power system architecture, the evolution of the control strategy, and its performance over industry standard drive cycles.

Transition to a hydrogen fuel cell transit bus fleet for Canadian urban transit system

International Nuclear Information System (INIS)

Ducharme, P.

2004-01-01

'Full text:' The Canadian Transportation Fuel Cell Alliance (CTFCA), created by the Canadian Government as part of its 2000 Climate Change Action Plan, has commissioned MARCON-DDM's Hydrogen Intervention Team (HIT) to provide a roadmap for urban transit systems that wish to move to hydrogen fuel cell-powered bus fleets. HIT is currently in the process of gathering information from hydrogen technology providers, bus manufacturers, fuelling system providers and urban transit systems in Canada, the US and Europe. In September, HIT will be in a position to provide a preview of its report to the CTFCA, due for October 2004. The planned table of contents includes: TOMORROW'S FUEL CELL (FC) URBAN TRANSIT BUS - Powertrain, on-board fuel technologies - FC engine system manufacturers - Bus technical specifications, performances, operating characteristics - FC bus manufacturers TOMORROW'S FC TRANSIT PROPERTY - Added maintenance, facilities and fuelling infrastructure requirements - Supply chain implications - Environmental and safety issues - Alternative operational concepts PATHWAYS TO THE FUTURE - Choosing the future operational concept - 'Gap' assessment - how long from here to there? - Facilities and fleet adjustments, including fuelling infrastructure - Risk mitigation, code compliance measures TRANSITIONAL CONSIDERATIONS - Cost implications - Transition schedule (author)

The atmospheric boundary layer evening transitions: an observational and numerical study from two different datasets

Science.gov (United States)

Sastre, Mariano; Yagüe, Carlos; Román-Cascón, Carlos; Maqueda, Gregorio; Ander Arrillaga, Jon

2015-04-01

In this work we study the temporal evolution of the Atmospheric Boundary Layer (ABL) along the transition period from a diurnal typical convection to a nocturnal more frequently stable situation. This period is known as late afternoon or evening transition, depending on the specific definitions employed by different authors [1]. In order to obtain a proper characterization, we try to learn whether or not the behaviour of these transitional boundary layers is strongly dependent on local conditions. To do so, two sets of evening transitions are studied from data collected at two different experimental sites. These locations correspond to research facilities named CIBA (Spain) and CRA (France), which are the places where atmospheric field campaigns have been conducted during the last years, such as CIBA2008 and BLLAST 2011, respectively. In order to get comparable situations, we focus especially on transitions with weak synoptic forcing, and consider daily astronomical sunset as a reference time. A statistical analysis on main parameters related to the transition is carried out for both locations, and the average behaviour is shown as well as extreme values according to the timing. A similar pattern in the qualitative evolution of many variables is found. Nevertheless, several relevant differences in the progress of key variables are obtained too. Moisture, both from the soil and the air, is thought to have great relevance in explaining many of the differences found between the two sites. Some case studies are explored, focusing on the role played by the atmospheric turbulence. Complementary, numerical experiments are also performed using the Weather Research and Forecast (WRF) mesoscale model, in order to test the role of humidity, by artificially varying it in some of the simulations. [1] Lothon, M. and coauthors (2014): The BLLAST field experiment: Boundary-Layer Late Afternoon and Sunset Turbulence. Atmos. Chem. Phys., 14, 10931-10960.

The Effect of Person Centered Planning Activities on the IEP/Transition Planning Process.

Science.gov (United States)