Science.gov

Sample records for related transport cross

  1. Elastic, charge transfer, and related transport cross sections for proton impact of atomic hydrogen for astrophysical and laboratory plasma modeling

    NASA Astrophysics Data System (ADS)

    Schultz, D. R.; Ovchinnikov, S. Yu; Stancil, P. C.; Zaman, T.

    2016-04-01

    Updating and extending previous work (Krstić and Schultz 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3458 and other references) comprehensive calculations were performed for elastic scattering and charge transfer in proton—atomic hydrogen collisions. The results, obtained for 1301 collision energies in the center-of-mass energy range of 10‑4–104 eV, are provided for integral and differential cross sections relevant to transport modeling in astrophysical and other plasma environments, and are made available through a website. Use of the data is demonstrated through a Monte Carlo transport simulation of solar wind proton propagation through atomic hydrogen gas representing a simple model of the solar wind interaction with heliospheric neutrals.

  2. Elastic and Related Transport Cross Sections, Charge Transfer: Data from the Controlled Fusion Atomic Data Center (CFADC)

    DOE Data Explorer

    Krstic, P. S; Schultz, D. R.

    Data files available in this section of the Controlled Fusion Atomic Data Center (CFADC) are found under the following headings: • Isotopomers of hydrogen ions, atoms and molecules and helium • Vibrationally excited states of hydrogen molecule with proton, and hydrogen molecular ion with hydrogen • Isotopomers of hydrogen ions with carbon • Isotopomers of hydrogen ions with argon • Hydrogen ions with neon • Hydrogen ions with krypton • Hydrogen ions with xenon • Elastic and other cross sections from ApJ xxx, yyyy (2008) Each heading is a link to more information, the data, and customized interfaces. (Specialized Interface)

  3. Cross-sectional study assessing HIV-related knowledge, attitudes and behavior in the Namibian truck transport sector: Readjusting HIV prevention programs in the workplace.

    PubMed

    Kiderlen, Til R; Conteh, Michael; Roll, Stephanie; Seeling, Stefanie; Weinmann, Stefan

    2015-01-01

    The objectives of this study were to assess the current status of HIV-related knowledge, attitudes, and behavior (KAB) of employees in the private transport sector in Namibia and to compare companies with established HIV workplace program (WPPs) with those that have recently initiated the implementation of such programs. The study was designed as a cross-sectional questionnaire-based survey. Between January and March 2011, the survey was conducted in the Namibian truck transport sector in six companies of different sizes. The participants were selected randomly from the workforce. Data collection was based on a KAB questionnaire. The range of correct answers to the survey concerning the knowledge of HIV transmission was 67-95%. Twenty percent of the employees had never been tested for HIV. Additionally, risky sexual behaviors were quite prevalent and included having multiple concurrent partners and the use of sex for incentives. This study revealed that drivers and laborers were especially at risk for such behaviors. The employees of companies with established WPPs were tested for HIV more often than those of companies with new WPPs; however, aside from this difference, only minor differences were observed between the two groups. The findings of this study highlight the need for on-going HIV information and prevention campaigns that focus on the special needs of mobile and low-income workers. WPPs should be tailored accordingly and shift their focus to more practical approaches, such as voluntary counseling and testing (VCT), to increase their effectiveness. PMID:25805432

  4. Transportation. The Neglected Related Service.

    ERIC Educational Resources Information Center

    Carter, Mary; And Others

    This monograph presents a five-module staff training program used to improve the related service of transportation of children with disabilities in Union County, North Carolina. Each module takes from 4 to more than 8 hours of training and bus drivers and transportation safety assistants with current certificates in all five modules receive a…

  5. The importance of transport parameter cross correlations in natural systems radioactive transport models

    SciTech Connect

    Reimus, Paul W

    2011-01-03

    Transport parameter cross correlations are rarely considered in models used to predict radionuclide transport in natural systems. In this paper, it is shown that parameter cross correlations could have a significant impact on radionuclide transport predictions in saturated media. In fractured rock, the positive correlation between fracture apertures and groundwater residence times is shown to result in significantly less retardation due to matrix diffusion than is predicted without the correlation. The suppression of matrix diffusion is further amplified by a tendency toward larger apertures, smaller matrix diffusion coefficients, and less sorption capacity in rocks of lower matrix porosity. In a hypothetical example, strong cross correlations between these parameters result in a decrease in predicted radionuclide travel times of an order of magnitude or more relative to travel times calculated with uncorrelated parameters. In porous media, expected correlations between permeability, porosity, and sorption capacity also result in shorter predicted travel times than when the parameters are assumed to be uncorrelated. Individual parameter standard deviations can also have a significant influence on predicted radionuclide travel times, particularly when cross correlations are considered.

  6. CROSS-SHORE TRANSPORT OF BIMODAL SANDS.

    USGS Publications Warehouse

    Richmond, Bruce M.; Sallenger,, Asbury H., Jr.

    1985-01-01

    Foreshore sediment level and sediment size were monitored as part of an extensive nearshore processes experiment - DUCK 82. Changes in foreshore texture were compared with computed values of onshore transported material based on current measurements from the surf zone and sediment transport theory. Preliminary results indicate reasonable agreement between predicted size of sediment transported onshore and beach texture changes. It is also demonstrated that coarse sediment may move onshore while finer material may simultaneously move offshore. Refs.

  7. Cross-shelf transport and dispersion due to baroclinic instabilities

    NASA Astrophysics Data System (ADS)

    Thyng, Kristen; Hetland, Robert

    2014-05-01

    The dominant forcing mechanisms for the circulation in the northwestern Gulf of Mexico are largely determined by location relative to the shelf break. On the inner shelf, the flow is mostly controlled by the wind and on the outer shelf is affected by the mesoscale loop-current eddies. However, in the summer, baroclinic instabilities can develop along the boundary of the mid-shelf river plume front, leading to large eddies (~50 km length scale) that can reach across the entire shelf and strongly affect the local flow field. These instabilities advect fresher water toward the shelf edge and pull denser water back toward the coast. The details of how the flow crosses between these two regimes is of interest because it controls the flux of river-borne biogeochemical properties to the deep ocean, as well as for the potential onshore transport of oil from offshore spills. We approach this problem using a high resolution numerical model of the Texas-Louisiana shelf run using the Regional Ocean Modeling System (ROMS) and a Lagrangian particle tracking model (TRACMASS). By initializing drifters at the sources of fresh water (the Atchafalaya and Mississippi rivers) in the numerical model, we are able to explicitly track its trajectory through the numerical domain in time. These trajectories can then be used to characterize the cross-shelf transport and lateral dispersion due to the instabilities caused by the presence of the fresher water. We expect the transport and dispersion to be enhanced when compared with these quantities at other times of the year when the instabilities are not present, as well as with other regions of the shelf break that are farther from the plume edge area. Additionally, an idealized numerical model of a shelf break with both horizontal and vertical density gradients has been run through relevant parameter spaces to examine the range of baroclinic instabilities. Drifters are run in these simulations for comparison of transport and dispersion with

  8. Precise Relative Earthquake Magnitudes from Cross Correlation

    DOE PAGESBeta

    Cleveland, K. Michael; Ammon, Charles J.

    2015-04-21

    We present a method to estimate precise relative magnitudes using cross correlation of seismic waveforms. Our method incorporates the intercorrelation of all events in a group of earthquakes, as opposed to individual event pairings relative to a reference event. This method works well when a reliable reference event does not exist. We illustrate the method using vertical strike-slip earthquakes located in the northeast Pacific and Panama fracture zone regions. Our results are generally consistent with the Global Centroid Moment Tensor catalog, which we use to establish a baseline for the relative event sizes.

  9. Truesdell transport in general relativity

    NASA Astrophysics Data System (ADS)

    Walwadkar, B. B.

    1983-12-01

    The Truesdell transport of a contravariant tensor fieldX ab is defined with respect to a time-like vector fieldu a analogous to the classical definition in continuum mechanics. Truesdell stress rate of the shear tensor (σ ab) and the metric tensor (g ab ) is Truesdell transported alongl a if and only if the medium is rigid. In case of two-dimensional projection operatorsγ ab andγ *ab are Truesdell transported along timelike vector fieldu a if and only if they are expansion free (alongu a ) withtau = λ - bar σ + μ - ρ = 0. A collapsing perfect fluid is Truesdell transported with respect tou a if and only if it is expansion free (alongu a ), energy density (D), pressure (P), and density of neutrino radiation (q) are conserved alongu a withσt=λ,α + bar β = tau = 0. In all the above cases, analogous results are found alongl a ,n a , andm a using freedom conditions (k=ɛ=π=γ+γ -=0) as null rays are always restricted to be geodesic (Carter [1]).

  10. Cross-Sectional Transport Imaging in a Multijunction Solar Cell

    SciTech Connect

    Haegel, Nancy M.; Ke, Chi-Wen; Taha, Hesham; Guthrey, Harvey; Fetzer, C. M.; King, Richard

    2015-06-14

    Combining highly localized electron-beam excitation at a point with the spatial resolution capability of optical near-field imaging, we have imaged carrier transport in a cross-sectioned multijunction (GaInP/GaInAs/Ge) solar cell. We image energy transport associated with carrier diffusion throughout the full width of the middle (GaInAs) cell and luminescent coupling from point excitation in the top cell GaInP to the middle cell. Supporting cathodoluminescence and near-field photoluminescence measurements demonstrate excitation-dependent Fermi level splitting effects that influence cross-sectioned spectroscopy results as well as transport limitations on the spatial resolution of cross-sectional measurements.

  11. Contrasting local retention and cross-shore transports of the East Australian Current and the Leeuwin Current and their relative influences on the life histories of small pelagic fishes

    NASA Astrophysics Data System (ADS)

    Condie, S. A.; Mansbridge, J. V.; Cahill, M. L.

    2011-03-01

    Transport between shelf and offshore environments supports a significant proportion of ocean primary productivity and is critical to the life cycle of many marine species. While fundamental differences in the underlying dynamics of eastern and western boundary currents have been recognized and studied for more than half a century, the implications for physical dispersal rates have received much less attention. In this study we explore how Australia's two major boundary current systems, the East Australian Current and the Leeuwin Current, differ in their local retention and cross-shore transports in the upper water column and how these differences favor contrasting life histories of small pelagic fishes. The results suggest that the East Australian Current forms a partial barrier to onshore transport, but is effective in entraining shelf waters and transporting them offshore, particularly in the region where the current separates from the coast. Blue mackerel ( Scomber australasicus) spawn on the outer-shelf in this separation region and may thereby maximize the dispersion of eggs and larvae in the mainly oligotrophic waters of the southern Coral Sea. In contrast, the Leeuwin Current system promotes onshore transport through the combined effects of mean onshore flow and eddy-induced mixing. In the Great Australian Bight, sardine ( Sardinops sagax) and anchovy ( Engraulis australis) may exploit the high coastal retention of the Leeuwin Current system by spawning on the inner-shelf during summer when the current is weakest and winds assist retention and enhance production through local upwelling.

  12. Investigation of anisotropic thermal transport in cross-linked polymers

    NASA Astrophysics Data System (ADS)

    Simavilla, David Nieto

    Thermal transport in lightly cross-linked polyisoprene and polybutadine subjected to uniaxial elongation is investigated experimentally. We employ two experimental techniques to assess the effect that deformation has on this class of materials. The first technique, which is based on Forced Rayleigh Scattering (FRS), allows us to measure the two independent components of the thermal diffusivity tensor as a function of deformation. These measurements along with independent measurements of the tensile stress and birefringence are used to evaluate the stress-thermal and stress-optic rules. The stress-thermal rule is found to be valid for the entire range of elongations applied. In contrast, the stress-optic rule fails for moderate to large stretch ratios. This suggests that the degree of anisotropy in thermal conductivity depends on both orientation and tension in polymer chain segments. The second technique, which is based on infrared thermography (IRT), allows us to measure anisotropy in thermal conductivity and strain induced changes in heat capacity. We validate this method measurements of anisotropic thermal conductivity by comparing them with those obtained using FRS. We find excellent agreement between the two techniques. Uncertainty in the infrared thermography method measurements is estimated to be about 2-5 %. The accuracy of the method and its potential application to non-transparent materials makes it a good alternative to extend current research on anisotropic thermal transport in polymeric materials. A second IRT application allows us to investigate the dependence of heat capacity on deformation. We find that heat capacity increases with stretch ratio in polyisoprene specimens under uniaxial extension. The deviation from the equilibrium value of heat capacity is consistent with an independent set of experiments comparing anisotropy in thermal diffusivity and conductivity employing FRS and IRT techniques. We identify finite extensibility and strain

  13. Electron Transport Simulations of 4-Terminal Crossed Graphene Nanoribbons Devices

    NASA Astrophysics Data System (ADS)

    Brandimarte, Pedro; Papior, Nick R.; Engelund, Mads; Garcia-Lekue, Aran; Frederiksen, Thomas; Sánchez-Portal, Daniel

    Recently, it has been reported theoretically a current switching mechanism by voltage control in a system made by two perpendicular 14-armchair graphene nanoribbons (GNRs). In order to investigate the possibilities of using crossed GNRs as ON/OFF devices, we have studied their electronic and transport properties as function structural parameters determining the crossing. Our calculations were performed with TranSIESTA code, which has been recently generalized to consider N >= 1 arbitrarily distributed electrodes at finite bias. We find that the transmission along each individual GNR and among them strongly depends on the stacking. For a 60° rotation angle, the lattice matching in the crossing region provokes a strong scattering effect that translates into an increased interlayer transmission. FP7 FET-ICT PAMS-project (European Commission, contract 610446), MINECO (Grant MAT2013-46593-C6-2-P) and Basque Dep. de Educación, UPV/EHU (Grant IT-756-13).

  14. Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

    ERIC Educational Resources Information Center

    Ruiz, Francisco J.; Luciano, Carmen

    2011-01-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among…

  15. Electron transport in argon in crossed electric and magnetic fields

    PubMed

    Ness; Makabe

    2000-09-01

    An investigation of electron transport in argon in the presence of crossed electric and magnetic fields is carried out over a wide range of values of electric and magnetic field strengths. Values of mean energy, ionization rate, drift velocity, and diffusion tensor are reported here. Two unexpected phenomena arise; for certain values of electric and magnetic field we find regions where the swarm mean energy decreases with increasing electric fields for a fixed magnetic field and regions where swarm mean energy increases with increasing magnetic field for a fixed electric field. PMID:11088933

  16. Anomalous cross field electron transport in a Hall effect thruster

    SciTech Connect

    Boniface, C.; Garrigues, L.; Hagelaar, G. J. M.; Boeuf, J. P.; Gawron, D.; Mazouffre, S.

    2006-10-16

    The origin of anomalous electron transport across the magnetic field in the channel of a Hall effect thruster has been the subject of controversy, and the relative importance of electron-wall collisions and plasma turbulence on anomalous transport is not clear. From comparisons between Fabry-Perot measurements and hybrid model calculations of the ion velocity profile in a 5 kW Hall effect thruster, we deduce that one and the same mechanism is responsible for anomalous electron transport inside and outside the Hall effect thruster channel. This suggests that the previous assumption that Bohm anomalous conductivity is dominant outside the thruster channel whereas electron-wall conductivity prevails inside the channel is not valid.

  17. Universal relations of transport coefficients from holography

    SciTech Connect

    Cherman, Aleksey; Nellore, Abhinav

    2009-09-15

    We show that there are universal high-temperature relations for transport coefficients of plasmas described by a wide class of field theories with gravity duals. These theories can be viewed as strongly coupled large-N{sub c} conformal field theories deformed by one or more relevant operators. The transport coefficients we study are the speed of sound and bulk viscosity, as well as the conductivity, diffusion coefficient, and charge susceptibility of probe U(1) charges. We show that the sound bound v{sub s}{sup 2}{<=}1/3 is satisfied at high temperatures in these theories and also discuss bounds on the diffusion coefficient, the conductivity, and the bulk viscosity.

  18. Barrier Crossing and Transport Activated by Kangaroo Fluctuations

    NASA Astrophysics Data System (ADS)

    Kostur, M.; Luczka, J.

    1999-01-01

    We study barrier crossing of Brownian particles in a bistable symmetric potential and transport of Brownian particles in spatially periodic structures, driven by both kangaroo fluctuations and thermal equilibrium noise of zero mean values. We consider exponentially and algebraically correlated kangaroo fluctuations. Starting with the full Newton--Langevin equation for the Brownian particle and by introducing scaling as well as dimensionless variables, we show that the equation is very well approximated by overdamped dynamics in which inertial effects can be neglected. We analyze properties of selected macroscopic characteristics of the system such as the mean first passage time (MFPT) of particles from one minimum of the bistable potential to the other and mean stationary velocity of particles moving in a spatially periodic potential. In dependence upon statistics of kangaroo fluctuations and temperature of the system, macroscopic characteristics exhibit distinctive non-monotonic behavior. Accordingly, there exist optimal statistics of fluctuations optimizing macroscopic characteristics.

  19. The transport of relative canonical helicity

    SciTech Connect

    You, S.

    2012-09-15

    The evolution of relative canonical helicity is examined in the two-fluid magnetohydrodynamic formalism. Canonical helicity is defined here as the helicity of the plasma species' canonical momentum. The species' canonical helicity are coupled together and can be converted from one into the other while the total gauge-invariant relative canonical helicity remains globally invariant. The conversion is driven by enthalpy differences at a surface common to ion and electron canonical flux tubes. The model provides an explanation for why the threshold for bifurcation in counter-helicity merging depends on the size parameter. The size parameter determines whether magnetic helicity annihilation channels enthalpy into the magnetic flux tube or into the vorticity flow tube components of the canonical flux tube. The transport of relative canonical helicity constrains the interaction between plasma flows and magnetic fields, and provides a more general framework for driving flows and currents from enthalpy or inductive boundary conditions.

  20. Transport-parallel cross folds within a mid-crustal Caledonian thrust stack, northern Scotland

    NASA Astrophysics Data System (ADS)

    Alsop, G. I.; Holdsworth, R. E.; Strachan, R. A.

    1996-06-01

    Cross folds are typically associated with zones of anomalous foliation trend that lie at high angles to orogenic strike. This case study concentrates on a region of transport-parallel cross folding developed by buckling during Caledonian ductile thrusting within the Moine and Naver Nappes of northern Scotland. Detailed structural analysis reveals a systematic angular relationship between the trend of tectonic transport, fold axes, and the vergence of minor folds. Large-scale cross folding is considered here to be related to wrench-dominated differential shearing during thrust-sense displacements along an important, possibly out-of-sequence structure, here termed the Ben Blandy Shear Zone. This suggests that patterns of folding within the internal parts of the Caledonian orogen in Scotland are principally controlled by the kinematic constraints imposed by low-angle thrusting. Thus, early, 'main-phase' folding is associated with the initiation and propagation of ductile thrusts, whilst later, secondary structures, including cross folds can be related to the development of flow perturbations during displacement along well-established, regionally important detachments.

  1. Cross-shelf transport of freshwater in the New Jersey shelf

    NASA Astrophysics Data System (ADS)

    Castelao, R. M.; Glenn, S.; Schofield, O.; Chant, R.; Kohut, J.

    2007-05-01

    The New Jersey Shelf Observing System, which includes real-time access to the international constellation of ocean satellites, a nested HF CODAR radar network, cabled moorings and a fleet of Webb Sloccum gliders, is used to investigate the freshwater content over the New Jersey shelf. Repeated hydrographic surveys about 100 km south of the Hudson River mouth were conducted using gliders during spring and summer 2006. Observations reveal a strong seasonal cycle in the surface salinity. Buoyant water is restricted to being close to the coast during spring, but spans the entire shelf width during summer. During late July and August, freshwater lenses with large density anomaly are found up to 100 km from the coast. The cross-shelf transport of the freshwater is inconsistent with a model based on Ekman dynamics [Lentz, 2004], suggesting that other processes are responsible for the rapid cross-shelf transport. Surface velocity maps derived from HF radar, satellite imagery and drifter trajectories revealed the existence of a jet directed offshore and to the south, from near the river mouth toward the study region. This provides a direct pathway for transporting freshwater and any biogeochemical material it contains (including phytoplankton, dissolved organic and non-algal particulate matter) across the shelf. The highest frequency of observation of the freshwater lenses offshore occurs when the jet transport is large, and the river discharge is relatively high. The transport in the jet is correlated with upwelling winds on scales of a few days.

  2. Relative charge transfer cross section from Rb (4d)

    NASA Astrophysics Data System (ADS)

    Shah, M. H.; Camp, H. A.; Trachy, M. L.; Fléchard, X.; Gearba, M. A.; Nguyen, H.; Brédy, R.; Lundeen, S. R.; Depaola, B. D.

    2005-08-01

    Relative charge transfer cross section measurements for the excited state Rb(4d) with 7keV Na+ is reported. The specific channels reported are Na++Rb(4d5/2)→Na(nl)+Rb+ , where the dominant transfer cross sections channels were nl=3d and 4s . Using a combination of a magneto-optical trap and recoil ion momentum spectroscopy (MOTRIMS methodology), the cross sections were measured relative to the previously studied Na++Rb(5s,5p) systems at the same collision energy.

  3. Relative charge transfer cross section from Rb(4d)

    SciTech Connect

    Shah, M.H.; Camp, H.A.; Trachy, M.L.; De Paola, B.D.; Flechard, X.; Gearba, M.A.; Nguyen, H.; Bredy, R.; Lundeen, S.R.

    2005-08-15

    Relative charge transfer cross section measurements for the excited state Rb(4d) with 7 keV Na{sup +} is reported. The specific channels reported are Na{sup +}+Rb(4d{sub 5/2}){yields}Na(nl)+Rb{sup +}, where the dominant transfer cross sections channels were nl=3d and 4s. Using a combination of a magneto-optical trap and recoil ion momentum spectroscopy (MOTRIMS methodology), the cross sections were measured relative to the previously studied Na{sup +}+Rb(5s,5p) systems at the same collision energy.

  4. Prospects for cost reductions from relaxing additional cross-border measures related to livestock trade.

    PubMed

    Hop, G E; Mourits, M C M; Slager, R; Oude Lansink, A G J M; Saatkamp, H W

    2013-05-01

    Compared with the domestic trade in livestock, intra-communal trade across the European Union (EU) is subject to costly, additional veterinary measures. Short-distance transportation just across a border requires more measures than long-distance domestic transportation, while the need for such additional cross-border measures can be questioned. This study examined the prospects for cost reductions from relaxing additional cross-border measures related to trade within the cross-border region of the Netherlands (NL) and Germany (GER); that is, North Rhine Westphalia and Lower Saxony. The study constructed a deterministic spread-sheet cost model to calculate the costs of both routine veterinary measures (standard measures that apply to both domestic and cross-border transport) and additional cross-border measures (extra measures that only apply to cross-border transport) as applied in 2010. This model determined costs by stakeholder, region and livestock sector, and studied the prospects for cost reduction by calculating the costs after the relaxation of additional cross-border measures. The selection criteria for relaxing these measures were (1) a low expected added value on preventing contagious livestock diseases, (2) no expected additional veterinary risks in case of relaxation of measures and (3) reasonable cost-saving possibilities. The total cost of routine veterinary measures and additional cross-border measures for the cross-border region was €22.1 million, 58% (€12.7 million) of which came from additional cross-border measures. Two-thirds of this €12.7 million resulted from the trade in slaughter animals. The main cost items were veterinary checks on animals (twice in the case of slaughter animals), export certification and control of export documentation. Four additional cross-border measures met the selection criteria for relaxation. The relaxation of these measures could save €8.2 million (€5.0 million for NL and €3.2 million for GER) annually

  5. Solar coronal loop heating by cross-field wave transport

    NASA Technical Reports Server (NTRS)

    Amendt, Peter; Benford, Gregory

    1989-01-01

    Solar coronal arches heated by turbulent ion-cyclotron waves may suffer significant cross-field transport by these waves. Nonlinear processes fix the wave-propagation speed at about a tenth of the ion thermal velocity, which seems sufficient to spread heat from a central core into a large cool surrounding cocoon. Waves heat cocoon ions both through classical ion-electron collisions and by turbulent stochastic ion motions. Plausible cocoon sizes set by wave damping are in roughly kilometers, although the wave-emitting core may be only 100 m wide. Detailed study of nonlinear stabilization and energy-deposition rates predicts that nearby regions can heat to values intermediate between the roughly electron volt foot-point temperatures and the about 100 eV core, which is heated by anomalous Ohmic losses. A volume of 100 times the core volume may be affected. This qualitative result may solve a persistent problem with current-driven coronal heating; that it affects only small volumes and provides no way to produce the extended warm structures perceptible to existing instruments.

  6. Isentropic Cross-Tropopause Ozone Transport in the Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    Jing, P.; Cunnold, D. M.; Wang, H. J.; Yang, E.-S.

    2004-01-01

    This paper investigates isentropic ozone exchange between the extratropical lower stratosphere and the subtropical upper troposphere in the Northern Hemisphere. The quantification method is based on the potential vorticity (PV) mapping of Stratospheric Aerosol and Gas Experiment (SAGE)-II ozone measurements and contour advection calculations using the NASA Goddard Space Center Data Assimilation Office (DAO) analysis for the year 1990. The magnitude of the annual isentropic stratosphere-to-troposphere ozone flux is calculated to be approximately twice the flux that is directed from the troposphere into the stratosphere. The net effect is that approx.46 x 10(exp 9) kg/yr of ozone are transferred quasi horizontally from the extratropical lower stratosphere into the subtropical upper troposphere between the isentropic surfaces of 330 and 370 K. The estimated monthly ozone fluxes show that the isentropic cross-tropopause ozone transport is stronger in summer/fall than in winter/ spring, and this seasonality is more obvious at the upper three levels (i.e., 345, 355, and 365 K) than at 335 K. The distributions of the estimated monthly ozone fluxes indicate that the isentropic stratosphere-to-troposphere ozone exchange is associated with wave breaking and occurs preferentially over the eastern Atlantic Ocean and northwest Africa in winter and over the Atlantic and Pacific Oceans in summer.

  7. A set of cross sections and transport coefficients for electrons in HBr

    NASA Astrophysics Data System (ADS)

    Šašić, O.; Dujko, S.; Makabe, T.; Petrović, Z. Lj.

    2012-04-01

    We have compiled a set of electron collision cross sections for HBr. It will be useful for a fluid modeling of HBr plasmas together with transport coefficients in both DC and RF, E and E × B fields. The calculation made use of a Monte Carlo technique. The transport coefficients are rather unstructured because the total cross section resembles that of a constant collisonal frequency model. Additional measurements of swarm parameters are required in order to obtain more acurate set of cross sections.

  8. Lessons learned related to packaging and transportation

    SciTech Connect

    Wallen, C.

    1995-12-31

    The use of lessons learned as a tool for learning from past experiences is well established, especially by many organizations within the nuclear industry. Every person has, at some time, used the principles of lessons learned to adopt good work practices based on their own experiences or the experiences of others. Lessons learned can also help to avoid the recurrence of adverse practices, which is often an area that most lessons-learned programs tend to focus on. This paper will discuss how lessons learned relate to packaging and transportation issues and events experienced at Department of Energy (DOE) facilities. It will also discuss the role performed by the Office of Nuclear and Facility Safety`s Office of Operating Experience Analysis and Feedback in disseminating lessons learned and operating experience feedback to the DOE complex. The central concept of lessons learned is that any organization should be able to learn from its own experiences and events. In addition, organizations should implement methodologies to scan external environments for lessons learned, to analyze and determine the relevance of lessons learned, and to bring about the necessary changes learned from these experiences. With increased concerns toward facility safety, the importance of utilizing the lessons-learned principles and the establishment of lessons-learned programs can not be overstated.

  9. Cross-domain analogies as relating derived relations among two separate relational networks.

    PubMed

    Ruiz, Francisco J; Luciano, Carmen

    2011-05-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among separate relational networks and by correlating participants' performance with a standard measure of analogical reasoning. In two experiments, adult participants first completed general intelligence and analogical reasoning tests. Subsequently, they were exposed to a computerized conditional discrimination training procedure designed to create two relational networks, each consisting of two 3-member equivalence classes. The critical test was a two-part analogical test in which participants had to relate combinatorial relations of coordination and distinction between the two relational networks. In Experiment 1, combinatorial relations for each network were individually tested prior to analogical testing, but in Experiment 2 they were not. Across both experiments, 65% of participants passed the analogical test on the first attempt. Moreover, results from the training procedure were strongly correlated with the standard measure of analogical reasoning. PMID:21547072

  10. Cross-Domain Analogies as Relating Derived Relations among Two Separate Relational Networks

    PubMed Central

    Ruiz, Francisco J; Luciano, Carmen

    2011-01-01

    Contemporary behavior analytic research is making headway in analyzing analogy as the establishment of a relation of coordination among common types of trained or derived relations. Previous studies have been focused on within-domain analogy. The current study expands previous research by analyzing cross-domain analogy as relating relations among separate relational networks and by correlating participants' performance with a standard measure of analogical reasoning. In two experiments, adult participants first completed general intelligence and analogical reasoning tests. Subsequently, they were exposed to a computerized conditional discrimination training procedure designed to create two relational networks, each consisting of two 3-member equivalence classes. The critical test was a two-part analogical test in which participants had to relate combinatorial relations of coordination and distinction between the two relational networks. In Experiment 1, combinatorial relations for each network were individually tested prior to analogical testing, but in Experiment 2 they were not. Across both experiments, 65% of participants passed the analogical test on the first attempt. Moreover, results from the training procedure were strongly correlated with the standard measure of analogical reasoning. PMID:21547072

  11. Cross-correlation-aided transport in stochastically driven accretion flows

    NASA Astrophysics Data System (ADS)

    Nath, Sujit Kumar; Chattopadhyay, Amit K.

    2014-12-01

    The origin of linear instability resulting in rotating sheared accretion flows has remained a controversial subject for a long time. While some explanations of such non-normal transient growth of disturbances in the Rayleigh stable limit were available for magnetized accretion flows, similar instabilities in the absence of magnetic perturbations remained unexplained. This dichotomy was resolved in two recent publications by Chattopadhyay and co-workers [Mukhopadhyay and Chattopadhyay, J. Phys. A 46, 035501 (2013), 10.1088/1751-8113/46/3/035501; Nath et al., Phys. Rev. E 88, 013010 (2013), 10.1103/PhysRevE.88.013010] where it was shown that such instabilities, especially for nonmagnetized accretion flows, were introduced through interaction of the inherent stochastic noise in the system (even a "cold" accretion flow at 3000 K is too "hot" in the statistical parlance and is capable of inducing strong thermal modes) with the underlying Taylor-Couette flow profiles. Both studies, however, excluded the additional energy influx (or efflux) that could result from nonzero cross correlation of a noise perturbing the velocity flow, say, with the noise that is driving the vorticity flow (or equivalently the magnetic field and magnetic vorticity flow dynamics). Through the introduction of such a time symmetry violating effect, in this article we show that nonzero noise cross correlations essentially renormalize the strength of temporal correlations. Apart from an overall boost in the energy rate (both for spatial and temporal correlations, and hence in the ensemble averaged energy spectra), this results in mutual competition in growth rates of affected variables often resulting in suppression of oscillating Alfven waves at small times while leading to faster saturations at relatively longer time scales. The effects are seen to be more pronounced with magnetic field fluxes where the noise cross correlation magnifies the strength of the field concerned. Another remarkable

  12. Traffic control devices, visibility, and railroad grade crossings. Transportation research record

    SciTech Connect

    1995-12-31

    The papers contained in this volume are primarily from the 74th Annual Meeting of the Transportation Research Board and the Symposium for Improving Visibility for the Night Traveler, which was held in May 1994 in Washington, D.C. They concern traffic signs and signals, highway visibility, and rail-highway grade crossing safety and research, addressing some of the problems and issues facing urban engineers as they grapple with the ever more complex traffic system. Readers with a specific interest in traffic control devices will find papers related to effective uses of variable message signs, comprehension of various types of traffic control devices and their effects on driver behavior, pedestrian crosswalk time requirements, and empirical analysis of two-way stop-controlled intersections. Readers with an interest in delineation and illumination will find papers on minimum retroreflectivity requirements, pavement marking visibility and detectability, curve delineation, traffic sign reading distances at night, and apparent nighttime color of pavement marking products. Closing out this Record are papers addressing the application of GIS to rail-highway crossing safety and the accuracy of U.S. Department of Transportation rail-highway grade crossing accident prediction models.

  13. Quantemol-N calculation of electron molecule cross sections and related parameters

    NASA Astrophysics Data System (ADS)

    Brigg, Will; Williams, Adam; Monahan, Derek; Tennyson, Jonathan

    2012-10-01

    Quantemol-N was originally developed as a wrapper for the UK Molecular R-Matrix codes, significantly accelarating data production rates for electron molecule collision calculations. Since its conception Quantemol-N has continuously been developed in the direction of the plasma industry, with many features being added to produce extended cross sections sets and related parameters. Recent additions include the calculation of differential cross sections, which provide momentum transfer and rotational excitation cross sections. These are used in turn to provide transport coefficients for verification of swarm calculations. Electron collisions with water have been used as a test bed. The code has also been generalised to calculate cross sections for aligned molecules, for example ones trapped on surfaces.

  14. Light-induced cross transport phenomena in a single-component gas

    SciTech Connect

    Chermyaninov, I. V.; Chernyak, V. G.

    2013-07-15

    The cross transport processes that occur in a single-component gas in a capillary and are caused by resonance laser radiation and pressure and temperature gradients are studied. An expression for entropy production is derived using a system of kinetic Boltzmann equations in a linear approximation. The kinetic coefficients that determine the transport processes are shown to satisfy the Onsager reciprocal relations at any Knudsen numbers and any character of the elastic interaction of gas particles with the capillary surface. The light-induced baro- and thermoeffects that take place in a closed heat-insulated system in the field of resonance laser radiation are considered. Analytical expressions are obtained for the Onsager coefficients in an almost free-molecular regime. The light-induced pressure and temperature gradients that appear in a closed heat-insulated capillary under typical experimental conditions are numerically estimated.

  15. Performance of a Cross-Flow Humidifier with a High Flux Water Vapor Transport Membrane

    SciTech Connect

    Ahluwalia, R. K.; Wang, X.; Johnson, W. B.; Berg, F.; Kadylak, D.

    2015-09-30

    Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flow humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.

  16. Performance of a cross-flow humidifier with a high flux water vapor transport membrane

    NASA Astrophysics Data System (ADS)

    Ahluwalia, R. K.; Wang, X.; Johnson, W. B.; Berg, F.; Kadylak, D.

    2015-09-01

    Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flow humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.

  17. Plant water relations I: uptake and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants, like all living things, are mostly water. Water is the matrix of life, and its availability determines the distribution and productivity of plants on earth. Vascular plants evolved structures that enable them to transport water long distances with little input of energy, but the hollow trach...

  18. Cross: An OWL Wrapper for Reasoning on Relational Databases

    NASA Astrophysics Data System (ADS)

    Champin, Pierre-Antoine; Houben, Geert-Jan; Thiran, Philippe

    One of the challenges of the Semantic Web is to integrate the huge amount of information already available on the standard Web, usually stored in relational databases. In this paper, we propose a formalization of a logic model of relational databases, and a transformation of that model into OWL, a Semantic Web language. This transformation is implemented in Cross, as an open-source prototype. We prove a relation between the notion of legal database state and the consistency of the corresponding OWL knowledge base. We then show how that transformation can prove useful to enhance databases, and integrate them in the Semantic Web.

  19. Supercritical droplet combustion and related transport phenomena

    NASA Technical Reports Server (NTRS)

    Yang, Vigor; Hsieh, K. C.; Shuen, J. S.

    1993-01-01

    An overview of recent advances in theoretical analyses of supercritical droplet vaporization and combustion is conducted. Both hydrocarbon and cryogenic liquid droplets over a wide range of thermodynamic states are considered. Various important high-pressure effects on droplet behavior, such as thermodynamic non-ideality, transport anomaly, and property variation, are reviewed. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influence on fluid transport, gas-liquid interfacial thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibit a considerable change in the combustion mechanism at the criticl pressure, mainly as a result of reduced mass diffusivity and latent heat of vaporization with increased pressure. The influence of droplet size on the burning characteristics is also noted.

  20. Neighbourhood environment, sitting time and motorised transport in older adults: a cross-sectional study in Hong Kong

    PubMed Central

    Barnett, Anthony; Cerin, Ester; Ching, Claudia S-K; Johnston, Janice M; Lee, Ruby S Y

    2015-01-01

    Objectives Sitting time is a public health concern. This study examined associations of objectively measured neighbourhood environmental attributes with non-transport sitting time and motorised transport in 484 Hong Kong older adults. Neighbourhood attributes encouraging walking may help older adults replace some sitting time at home and on motorised transport with light-to-moderate-intensity activities such as strolling around the neighbourhood or walking to/from neighbourhood destinations. Thus, we hypothesised environmental attributes found to be related to walking would show associations with non-transport sitting time and motorised transport opposite to those seen for walking. Design Cross-sectional. Setting Hong Kong, an ultradense urban environment. Participants 484 ethnic Chinese Hong Kong residents aged 65+ recruited from membership lists of four Hong Kong Elderly Health Centres representing catchment areas of low and high transport-related walkability stratified by socioeconomic status (response rate: 78%). Primary and secondary outcome measures Attributes of participants’ neighbourhood environments were assessed by environmental audits, while non-transport sitting time and motorised transport were ascertained using the International Physical Activity Questionnaire—Long Form (Chinese version). Results Daily non-transport sitting minutes were 283 (SD=128) and motorised transport 23 (SD=28). Prevalence of signs of crime/disorder, streetlights, public facilities (toilets and benches) and pedestrian safety were independently negatively related, and sloping streets positively related, to sitting outcomes. Places of worship in the neighbourhood were predictive of more, and prevalence of public transit points of less, non-transport sitting. Associations of either or both sitting outcomes with prevalence of food/grocery stores and presence of parks were moderated by path obstructions and signs of crime/disorder. Conclusions The findings suggest that access to

  1. BOXER: Fine-flux Cross Section Condensation, 2D Few Group Diffusion and Transport Burnup Calculations

    Energy Science and Technology Software Center (ESTSC)

    2010-02-01

    Neutron transport, calculation of multiplication factor and neutron fluxes in 2-D configurations: cell calculations, 2-D diffusion and transport, and burnup. Preparation of a cross section library for the code BOXER from a basic library in ENDF/B format (ETOBOX).

  2. 48 CFR 52.232-4 - Payments Under Transportation Contracts and Transportation-Related Services Contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 52.232-4 Payments Under Transportation... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Payments Under..., in solicitations and contracts for transportation or transportation-related services: Payments...

  3. 48 CFR 52.232-4 - Payments Under Transportation Contracts and Transportation-Related Services Contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PROVISIONS AND CONTRACT CLAUSES Text of Provisions and Clauses 52.232-4 Payments Under Transportation... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Payments Under..., in solicitations and contracts for transportation or transportation-related services: Payments...

  4. Negative Transportation and Cross-Linguistic Negative Evidence.

    ERIC Educational Resources Information Center

    Soga, Matsuo

    1972-01-01

    This paper considers whether the negative transportation (NT) rule operating in English is operative also in Japanese and whether investigation of the phenomenon in Japanese may provide new insights for English research. The discussion begins with an explanation and examples of the NT rule in English. Japanese cases are then studied, and the…

  5. Differential Cross Section Kinematics for 3-dimensional Transport Codes

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank

    2008-01-01

    In support of the development of 3-dimensional transport codes, this paper derives the relevant relativistic particle kinematic theory. Formulas are given for invariant, spectral and angular distributions in both the lab (spacecraft) and center of momentum frames, for collisions involving 2, 3 and n - body final states.

  6. [Transportation-related disease or motion sickness].

    PubMed

    Perrin, C

    1994-02-01

    The manifestations of motion sickness result from neurovegetative effects linked to a change in the data used by the equilibration function in spatial integration. The syndrome is an adaptation to a physical environment that is different from that in which we live. Although each type of situation involves manifestations with a certain specificity, there is a general table of cinetoses. For the person who must face an environment at risk (usually for professional reasons), it is necessary to obtain active and voluntary adaptation by repeated exposure to the triggering conditions. The occasional traveler can use preventive or curative drugs which usually associate parasympatholytic agents and amphetamines. Despite the association of the latter, the risk of lowered attention level is large enough to preclude this type of treatment in anyone assuming responsibility in transportation. PMID:8178101

  7. Cross-field transport in Goldreich-Sridhar magnetohydrodynamic turbulence

    NASA Astrophysics Data System (ADS)

    Fraschetti, F.

    2016-01-01

    I derive analytically the temporal dependence of the perpendicular transport coefficient of a charged particle in the three-dimensional anisotropic turbulence conjectured by Goldreich-Sridhar by implementing multispacecraft constraints on the turbulence power spectrum. The particle motion away from the turbulent local field line is assessed as gradient-curvature drift of the guiding center and compared with the magnetic field line random walk. At inertial scales much smaller than the turbulence outer scale, particles decorrelate from field lines in a free-streaming motion, with no diffusion. In the solar wind at 1 AU, for energy sufficiently small (<1 keV protons), the perpendicular average displacement due to field line tangling generally dominates over two decades of turbulent scales. However, for higher energies (≃25 MeV protons) within the range of multispacecraft measurements, the longitudinal spread originating from transport due to gradient-curvature drift reaches up to ≃10∘ -20∘. This result highlights the role of perpendicular transport in the interpretation of interplanetary and interstellar data.

  8. Cross-field transport in Goldreich-Sridhar magnetohydrodynamic turbulence.

    PubMed

    Fraschetti, F

    2016-01-01

    I derive analytically the temporal dependence of the perpendicular transport coefficient of a charged particle in the three-dimensional anisotropic turbulence conjectured by Goldreich-Sridhar by implementing multispacecraft constraints on the turbulence power spectrum. The particle motion away from the turbulent local field line is assessed as gradient-curvature drift of the guiding center and compared with the magnetic field line random walk. At inertial scales much smaller than the turbulence outer scale, particles decorrelate from field lines in a free-streaming motion, with no diffusion. In the solar wind at 1 AU, for energy sufficiently small (<1 keV protons), the perpendicular average displacement due to field line tangling generally dominates over two decades of turbulent scales. However, for higher energies (≃25 MeV protons) within the range of multispacecraft measurements, the longitudinal spread originating from transport due to gradient-curvature drift reaches up to ≃10^{∘}-20^{∘}. This result highlights the role of perpendicular transport in the interpretation of interplanetary and interstellar data. PMID:26871182

  9. Making sense of (exceptional) causal relations. A cross-cultural and cross-linguistic study

    PubMed Central

    Le Guen, Olivier; Samland, Jana; Friedrich, Thomas; Hanus, Daniel; Brown, Penelope

    2015-01-01

    In order to make sense of the world, humans tend to see causation almost everywhere. Although most causal relations may seem straightforward, they are not always construed in the same way cross-culturally. In this study, we investigate concepts of “chance,” “coincidence,” or “randomness” that refer to assumed relations between intention, action, and outcome in situations, and we ask how people from different cultures make sense of such non-law-like connections. Based on a framework proposed by Alicke (2000), we administered a task that aims to be a neutral tool for investigating causal construals cross-culturally and cross-linguistically. Members of four different cultural groups, rural Mayan Yucatec and Tseltal speakers from Mexico and urban students from Mexico and Germany, were presented with a set of scenarios involving various types of causal and non-causal relations and were asked to explain the described events. Three links varied as to whether they were present or not in the scenarios: Intention-to-Action, Action-to-Outcome, and Intention-to-Outcome. Our results show that causality is recognized in all four cultural groups. However, how causality and especially non-law-like relations are interpreted depends on the type of links, the cultural background and the language used. In all three groups, Action-to-Outcome is the decisive link for recognizing causality. Despite the fact that the two Mayan groups share similar cultural backgrounds, they display different ideologies regarding concepts of non-law-like relations. The data suggests that the concept of “chance” is not universal, but seems to be an explanation that only some cultural groups draw on to make sense of specific situations. Of particular importance is the existence of linguistic concepts in each language that trigger ideas of causality in the responses from each cultural group. PMID:26579028

  10. Investigation of cross-linking characteristics of novel hole-transporting materials for solution-processed phosphorescent OLEDs

    NASA Astrophysics Data System (ADS)

    Lee, Jaemin; Ameen, Shahid; Lee, Changjin

    2016-04-01

    After the success of commercialization of the vacuum-evaporated organic light-emitting diodes (OLEDs), solutionprocessing or printing of OLEDs are currently attracting much research interests. However, contrary to various kinds of readily available vacuum-evaporable OLED materials, the solution-processable OLED materials are still relatively rare. Hole-transporting layer (HTL) materials for solution-processed OLEDs are especially limited, because they need additional characteristics such as cross-linking to realize multilayer structures in solution-processed OLEDs, as well as their own electrically hole-transporting characteristics. The presence of such cross-linking characteristics of solutionprocessable HTL materials therefore makes them more challenging in the development stage, and also makes them essence of solution-processable OLED materials. In this work, the structure-property relationships of thermally crosslinkable HTL materials were systematically investigated by changing styrene-based cross-linking functionalities and modifying the carbazole-based hole-transporting core structures. The temperature dependency of the cross-linking characteristics of the HTL materials was systematically investigated by the UV-vis. absorption spectroscopy. The new HTL materials were also applied to green phosphorescent OLEDs, and their device characteristics were also investigated based on the chemical structures of the HTL materials. The device configuration was [ITO / PEDOT:PSS / HTL / EML / ETL / CsF / Al]. We found out that the chemical structures of the cross-linking functionalities greatly affect not only the cross-linking characteristics of the resultant HTL materials, but also the resultant OLED device characteristics. The increase of the maximum luminance and efficiency of OLEDs was evident as the cross-linking temperature decreases from higher than 200°C to at around 150°C.

  11. Noninvasive cross section reconstruction with transport theory constraints

    SciTech Connect

    Fredette, N.; Ragusa, J.; Bangerth, W.

    2012-07-01

    We consider the inverse problem of identifying the spatially variable absorption and scattering properties of a medium by measuring the exiting radiation when the body is actively interrogated. We formulate this inverse problem as a PDE-constrained optimization problem and solve it iteratively with Newton's method. The constraint is given by the radiative transport equation for neutral particles. Two examples are considered. The first is a dual inclusion domain with no scattering. This problem explores the convergence patterns of the method. The second problem is a central inclusion problem with scattering. This problem explores the optical thickness limit of the method. This optical thickness was determined to be 2-3 mean free paths. (authors)

  12. Electron Collision Cross Sections for the Cl2 Molecule from Electron Transport Coefficients

    NASA Astrophysics Data System (ADS)

    Tuan, Do Anh; Jeon, Byung-Hoon

    2011-08-01

    The measured electron transport coefficients (electron drift velocity, Townsend first ionization coefficient, electron attachment coefficient, and density-normalized effective ionization coefficient) in pure Cl2 have been analyzed to derive the currently best available electron collision cross section set of the elastic and inelastic electron collision cross sections for the Cl2 molecule using an electron swarm study and a two-term approximation of the Boltzmann equation for energy. The electron transport coefficients calculated using the derived cross sections are consistent with the experimental data over a wide range of E/N values (ratio of the electric field E to the neutral number density N). The present electron collision cross section set for the Cl2 molecule is the best available so far for quantitative numerical modeling plasma discharges for processing procedures with materials containing Cl2 molecules.

  13. Ab initio electron scattering cross-sections and transport in liquid xenon

    NASA Astrophysics Data System (ADS)

    Boyle, G. J.; McEachran, R. P.; Cocks, D. G.; Brunger, M. J.; Buckman, S. J.; Dujko, S.; White, R. D.

    2016-09-01

    Ab initio fully differential cross-sections for electron scattering in liquid xenon are developed from a solution of the Dirac–Fock scattering equations, using a recently developed framework (Boyle et al 2015 J. Chem. Phys. 142 154507) which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann’s equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10‑4–1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculations.

  14. A Comparison of Hyporheic Transport at a Cross-Vane Structure and Natural Riffle.

    PubMed

    Smidt, Samuel J; Cullin, Joseph A; Ward, Adam S; Robinson, Jesse; Zimmer, Margaret A; Lautz, Laura K; Endreny, Theodore A

    2015-01-01

    While restoring hyporheic flowpaths has been cited as a benefit to stream restoration structures, little documentation exists confirming that constructed restoration structures induce comparable hyporheic exchange to natural stream features. This study compares a stream restoration structure (cross-vane) to a natural feature (riffle) concurrently in the same stream reach using time-lapsed electrical resistivity (ER) tomography. Using this hydrogeophysical approach, we were able to quantify hyporheic extent and transport beneath the cross-vane structure and the riffle. We interpret from the geophysical data that the cross-vane and the natural riffle induced spatially and temporally unique hyporheic extent and transport, and the cross-vane created both spatially larger and temporally longer hyporheic flowpaths than the natural riffle. Tracer from the 4.67-h injection was detected along flowpaths for 4.6 h at the cross-vane and 4.2 h at the riffle. The spatial extent of the hyporheic zone at the cross-vane was 12% larger than that at the riffle. We compare ER results of this study to vertical fluxes calculated from temperature profiles and conclude significant differences in the interpretation of hyporheic transport from these different field techniques. Results of this study demonstrate a high degree of heterogeneity in transport metrics at both the cross-vane and the riffle and differences between the hyporheic flowpath networks at the two different features. Our results suggest that restoration structures may be capable of creating sufficient exchange flux and timescales of transport to achieve the same ecological functions as natural features, but engineering of the physical and biogeochemical environment may be necessary to realize these benefits. PMID:25408169

  15. 48 CFR 728.313 - Contract clauses for insurance of transportation or transportation-related services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... all U.S. marine insurance companies have a fair opportunity to bid for marine insurance when such... required for use in any USAID-direct contract where marine insurance is necessary or appropriate. ... insurance of transportation or transportation-related services. 728.313 Section 728.313 Federal...

  16. Cross-tropopause transport of excess 14C in a two-dimensional model

    NASA Astrophysics Data System (ADS)

    Shia, Run-Lie; Ko, Malcolm K. W.; Zou, Min; Kotamarthi, V. Rao

    1993-10-01

    The processed excess 14C data are used to calibrate the cross-tropopause transport in a two-dimensional model. The model results are used to diagnose the mechanisms responsible for cross-tropopause transport in the model and the sensitivity of the transport rate to the changes in the transport parameter. Although the total flux across the tropopause is dominated by the eddy diffusion flux along the isentropic surface due to the large values assigned to the diffusion coefficient Kyy at the boundary, the cross-tropopause transport is more sensitive to changes in the circulation. Nitrogen oxides emitted by engines of high-speed civil transport could cause ozone depletion in the lower stratosphere. The expected depletion is proportional to the amount of oxides of nitrogen retained in the stratosphere. For a typical fleet, lowering the tropopause height by 1.2 km can cause a 14-22% increase in the amount of reactive nitrogen retained in the stratosphere. Thus it is necessary to have a fine enough vertical resolution near the tropopause in the two-dimensional model for determining the stratospheric residence time of the engine emissions deposited near the tropopause.

  17. Transport of magnesium by a bacterial Nramp-related gene.

    PubMed

    Shin, Jung-Ho; Wakeman, Catherine A; Goodson, Jonathan R; Rodionov, Dmitry A; Freedman, Benjamin G; Senger, Ryan S; Winkler, Wade C

    2014-06-01

    Magnesium is an essential divalent metal that serves many cellular functions. While most divalent cations are maintained at relatively low intracellular concentrations, magnesium is maintained at a higher level (∼0.5-2.0 mM). Three families of transport proteins were previously identified for magnesium import: CorA, MgtE, and MgtA/MgtB P-type ATPases. In the current study, we find that expression of a bacterial protein unrelated to these transporters can fully restore growth to a bacterial mutant that lacks known magnesium transporters, suggesting it is a new importer for magnesium. We demonstrate that this transport activity is likely to be specific rather than resulting from substrate promiscuity because the proteins are incapable of manganese import. This magnesium transport protein is distantly related to the Nramp family of proteins, which have been shown to transport divalent cations but have never been shown to recognize magnesium. We also find gene expression of the new magnesium transporter to be controlled by a magnesium-sensing riboswitch. Importantly, we find additional examples of riboswitch-regulated homologues, suggesting that they are a frequent occurrence in bacteria. Therefore, our aggregate data discover a new and perhaps broadly important path for magnesium import and highlight how identification of riboswitch RNAs can help shed light on new, and sometimes unexpected, functions of their downstream genes. PMID:24968120

  18. Transport of Magnesium by a Bacterial Nramp-Related Gene

    PubMed Central

    Rodionov, Dmitry A.; Freedman, Benjamin G.; Senger, Ryan S.; Winkler, Wade C.

    2014-01-01

    Magnesium is an essential divalent metal that serves many cellular functions. While most divalent cations are maintained at relatively low intracellular concentrations, magnesium is maintained at a higher level (∼0.5–2.0 mM). Three families of transport proteins were previously identified for magnesium import: CorA, MgtE, and MgtA/MgtB P-type ATPases. In the current study, we find that expression of a bacterial protein unrelated to these transporters can fully restore growth to a bacterial mutant that lacks known magnesium transporters, suggesting it is a new importer for magnesium. We demonstrate that this transport activity is likely to be specific rather than resulting from substrate promiscuity because the proteins are incapable of manganese import. This magnesium transport protein is distantly related to the Nramp family of proteins, which have been shown to transport divalent cations but have never been shown to recognize magnesium. We also find gene expression of the new magnesium transporter to be controlled by a magnesium-sensing riboswitch. Importantly, we find additional examples of riboswitch-regulated homologues, suggesting that they are a frequent occurrence in bacteria. Therefore, our aggregate data discover a new and perhaps broadly important path for magnesium import and highlight how identification of riboswitch RNAs can help shed light on new, and sometimes unexpected, functions of their downstream genes. PMID:24968120

  19. Minority carrier transport in GaN and related materials

    NASA Astrophysics Data System (ADS)

    Chernyak, Leonid; Osinsky, Andrei; Schulte, Alfons

    2001-09-01

    Minority carrier transport properties are an indicator of AlGaN quality. This characteristic is particularly of significant importance for AlGaN-based bipolar devices. The goal of this review is to discuss different factors - temperature, doping level, dislocation density, electron current density - which affect minority carrier mobility, lifetime, and diffusion length, and to relate the changes in AlGaN transport properties to the functionality of electronic and optoelectronic devices.

  20. Steady-State Thermodynamics for Crossed Transport Phenomena of Heat and Matter

    NASA Astrophysics Data System (ADS)

    Nakashima, Kimie; Takeyama, Naokata

    1992-08-01

    Crossed transport phenomena of heat and matter are thermodynamically discussed by using transported enthalpy and entropy, and those of transport, without using linear kinetic equations. The steady-state thermodynamics developed here is effective in dealing with thermo-osmosis, thermal diffusion and thermoelectricity. It is important to distinguish between transported thermal quantities and those of transport in any case. All of the results obtained agree exactly with corresponding expressions of linear nonequilibrium thermodynamics based on the Onsager theorem of reciprocity. Quasithermodynamic ambiguities are consistently eliminated by introducing entropy generated internally, diS, in harmony with the second law of thermodynamics. At the same time, a few points confused by many authors are corrected.

  1. Deep convective cross-tropopause transport in the tropics and evidence by A-Train satellites

    NASA Astrophysics Data System (ADS)

    Wang, P.; Su, S.,; Charvat, Z.; Setvak, M.; Cheng, K.

    2012-04-01

    Cross-tropopause transport by deep convective clouds can be an (and perhaps the most) important source of water vapor in the stratosphere. Our previous studies have verified that deep convective cross-tropopause transport does occur rather regularly in midlatitudes. This transport is demonstrated by the presence of cloud top features of above anvil cirrus plumes and jumping cirrus phenomenon that have been observed by aircraft, satellite and ground-based observations. The present paper will demonstrate that the same mechanism occurs in the tropics. Because the tropics typically have weaker wind shear at the tropopause level, previous observation did not show clear evidence of the presence of such cross-tropopause features. But the recent NSAS A-Train satellites, especially CloudSat, CALIPSO and MODIS, provide both horizontal cloud top and vertical cross-sectional views of the cloud structure and making the identification of such features much less unambiguous. In this study, we will first use cloud resolving model simulations of tropical deep connective storms to show that the gravity wave breaking mechanism and instability will cause moisture (condensed water and vapor) to be transported through the tropopause even in this weaker wind shear environment. Model animations will be shown in the conference. We will then show that the modeled storm top features match well with many recent observations by A-Train satellites. The model results and satellite observations agree not only in morphological similarity but also in the spatial extent and structure in both horizontal and vertical structure. Thus, both the model results and satellite observations demonstrate unambiguously that cross-tropopause transport of water vapor by deep convective clouds in the tropics does occur, and it should be assessed carefully for its global climatic impact.

  2. Transport model based on three-dimensional cross-section generation for TRIGA core analysis

    NASA Astrophysics Data System (ADS)

    Kriangchaiporn, Nateekool

    This dissertation addresses the development of a reactor core physics model based on 3-D transport methodology utilizing 3-D multigroup fuel lattice cross-section generation and core calculation for PSBR. The proposed 3-D transport calculation scheme for reactor core simulations is based on the TORT code. The methodology includes development of algorithms for 2-D and 3-D cross-section generation. The fine- and broad-group structures for the TRIGA cross-section generation problems were developed based on the CPXSD (Contributon and Point-wise Cross-Section Driven) methodology that selects effective group structure. Along with the study of cross section generation, the parametric studies for SN calculations were performed to evaluate the impact of the spatial meshing, angular, and scattering order variables and to obtain the suitable values for cross-section collapsing of the TRIGA cell problem. The TRIGA core loading 2 is used to verify and validate the selected effective group structures. Finally, the 13 group structure was selected to use for core calculations. The results agree with continuous energy for eigenvalues and normalized pin power distribution. The Monte Carlo solutions are used as the references.

  3. Intracellular Transport Routes for MHC I and Their Relevance for Antigen Cross-Presentation

    PubMed Central

    Adiko, Aimé Cézaire; Babdor, Joel; Gutiérrez-Martínez, Enric; Guermonprez, Pierre; Saveanu, Loredana

    2015-01-01

    Cross-presentation, in which exogenous antigens are presented via MHC I complexes, is involved both in the generation of anti-infectious and anti-tumoral cytotoxic CD8+ T cells and in the maintenance of immune tolerance. While cross-presentation was described almost four decades ago and while it is now established that some dendritic cell (DC) subsets are better than others in processing and cross-presenting internalized antigens, the involved molecular mechanisms remain only partially understood. Some of the least explored molecular mechanisms in cross-presentation concern the origin of cross-presenting MHC I molecules and the cellular compartments where antigenic peptide loading occurs. This review focuses on MHC I molecules and their intracellular trafficking. We discuss the source of cross-presenting MHC I in DCs as well as the role of the endocytic pathway in their recycling from the cell surface. Next, we describe the importance of the TAP peptide transporter for delivering peptides to MHC I during cross-presentation. Finally, we highlight the impact of innate immunity mechanisms on specific antigen cross-presentation mechanisms in which TLR activation modulates MHC I trafficking and TAP localization. PMID:26191062

  4. Border Crossings: Engaging Students in Diversity Work and Intergroup Relations

    ERIC Educational Resources Information Center

    Rose, Susan D.; Bylander, Joyce

    2007-01-01

    As an innovative model for diversity education, Dickinson College designed the "Crossing Borders" program to encourage culturally diverse students to live, work, and study together in multiple contexts both within the United States and abroad. Envisioning a series of crossings, the program brings together up to 20 students from Dickinson College,…

  5. 76 FR 64895 - Transportation and Related Equipment Technical Advisory Committee; Notice of Open Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ... Bureau of Industry and Security Transportation and Related Equipment Technical Advisory Committee; Notice of Open Meeting The Transportation and Related Equipment Technical Advisory ] Committee (TRANSTAC... export controls applicable to transportation and related equipment or technology. Agenda 1. Welcome...

  6. 76 FR 20949 - Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... Bureau of Industry and Security Transportation and Related Equipment Technical Advisory Committee; Notice of Partially Closed Meeting The Transportation and Related Equipment Technical Advisory Committee... controls applicable to transportation and related equipment or technology. Public Session 1. Welcome...

  7. Cross-shelf transport of pink shrimp larvae: Interactions of tidal currents, larval vertical migrations and internal tides

    USGS Publications Warehouse

    Criales, Maria M.; Browder, Joan A.; Mooers, C.N.K.; Robblee, M.B.; Cardenas, H.; Jackson, Thomas L.

    2007-01-01

    Transport and behavior of pink shrimp Farfantepenaeus duorarum larvae were investigated on the southwestern Florida (SWF) shelf of the Gulf of Mexico between the Dry Tortugas spawning grounds and Florida Bay nursery grounds. Stratified plankton samples and hydrographic data were collected at 2 h intervals at 3 stations located on a cross-shelf transect. At the Marquesas station, midway between Dry Tortugas and Florida Bay, internal tides were recognized by anomalously cool water, a shallow thermocline with strong density gradients, strong current shear, and a high concentration of pink shrimp larvae at the shallow thermocline. Low Richardson numbers occurred at the pycnocline depth, indicating vertical shear instability and possible turbulent transport from the lower to the upper layer where myses and postlarvae were concentrated. Analysis of vertically stratified plankton suggested that larvae perform vertical migrations and the specific behavior changes ontogenetically; protozoeae were found deeper than myses, and myses deeper than postlarvae. Relative concentrations of protozoea in the upper, middle and bottom layers were consistent with a diel vertical migration, whereas that of postlarvae and myses were consistent with the semidiurnal tides in phase with the flood tide. Postlarvae, the shallowest dwellers that migrate with a semidiurnal periodicity, experienced the largest net onshore flux and larval concentrations were highly correlated with the cross-shelf current. These results provide the first evidence of an onshore tidal transport (a type of selective tidal stream transport, STST), in decapod larvae migrating in continental shelf waters offshore, ca. 100 km from the coast and at a depth of 20 m, while approaching the coastal nursery grounds. Longer time series would be necessary to establish whether internal tides play any role in the larval onshore transport of this species and determine if the STST is the dominant onshore transport mechanism.

  8. Using beryllium-7 to assess cross-tropopause transport in global models

    NASA Astrophysics Data System (ADS)

    Liu, Hongyu; Considine, David B.; Horowitz, Larry W.; Crawford, James H.; Rodriguez, Jose M.; Strahan, Susan E.; Damon, Megan R.; Steenrod, Stephen D.; Xu, Xiaojing; Kouatchou, Jules; Carouge, Claire; Yantosca, Robert M.

    2016-04-01

    We use the Global Modeling Initiative (GMI) modeling framework to assess the utility of cosmogenic beryllium-7 (7Be), a natural aerosol tracer, for evaluating cross-tropopause transport in global models. The GMI chemical transport model (CTM) was used to simulate atmospheric 7Be distributions using four different meteorological data sets (GEOS1-STRAT DAS, GISS II' GCM, fvGCM, and GEOS4-DAS), featuring significantly different stratosphere-troposphere exchange (STE) characteristics. The simulations were compared with the upper troposphere and/or lower stratosphere (UT/LS) 7Be climatology constructed from ˜ 25 years of aircraft and balloon data, as well as climatological records of surface concentrations and deposition fluxes. Comparison of the fraction of surface air of stratospheric origin estimated from the 7Be simulations with observationally derived estimates indicates excessive cross-tropopause transport at mid-latitudes in simulations using GEOS1-STRAT and at high latitudes using GISS II' meteorological data. These simulations also overestimate 7Be deposition fluxes at mid-latitudes (GEOS1-STRAT) and at high latitudes (GISS II'), respectively. We show that excessive cross-tropopause transport of 7Be corresponds to overestimated stratospheric contribution to tropospheric ozone. Our perspectives on STE in these meteorological fields based on 7Be simulations are consistent with previous modeling studies of tropospheric ozone using the same meteorological fields. We conclude that the observational constraints for 7Be and observed 7Be total deposition fluxes can be used routinely as a first-order assessment of cross-tropopause transport in global models.

  9. Modeling organelle transport in branching dendrites with a variable cross-sectional area

    PubMed Central

    2010-01-01

    The purpose of this paper is to develop a method for calculating organelle transport in dendrites with a non-uniform cross-sectional area that depends on the distance from the neuron soma. The model is based on modified Smith–Simmons equations governing molecular motor-assisted organelle transport. The developed method is then applied to simulating organelle transport in branching dendrites with two particular microtubule (MT) orientations reported from experiments. It is found that the rate of organelle transport toward a dendrite’s growth cone heavily depends on the MT orientation, and since there is experimental evidence that the MT orientation in a particular region of a dendrite may depend on the dendrite’s developmental stage, the obtained results suggest that a rearrangement of the MT structure may depend on the amount of organelles needed at the growth cone. PMID:21886345

  10. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Requirements relating to transport indices and... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport indices..., transport and unloading are to be supervised by persons qualified in the transport of radioactive...

  11. CrossFit-related cervical internal carotid artery dissection.

    PubMed

    Lu, Albert; Shen, Peter; Lee, Paul; Dahlin, Brian; Waldau, Ben; Nidecker, Anna E; Nundkumar, Anoop; Bobinski, Matthew

    2015-08-01

    CrossFit is a high-intensity strength and conditioning program that has gained popularity over the past decade. Potential injuries associated with CrossFit training have been suggested in past reports. We report three cases of cervical carotid dissection that are associated with CrossFit workouts. Patient 1 suffered a distal cervical internal carotid artery (ICA) dissection near the skull base and a small infarct in Wernicke's area. He was placed on anticoagulation and on follow-up has near complete recovery. Patient 2 suffered a proximal cervical ICA dissection that led to arterial occlusion and recurrent middle cerebral artery territory infarcts and significant neurological sequelae. Patient 3 had a skull base ICA dissection that led to a partial Horner's syndrome but no cerebral infarct. While direct causality cannot be proven, intense CrossFit workouts may have led to the ICA dissections in these patients. PMID:25917634

  12. Electron Cross-field Transport in a Low Power Cylindrical Hall Thruster

    SciTech Connect

    A. Smirnov; Y. Raitses; N.J. Fisch

    2004-06-24

    Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are therefore more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. Electron cross-field transport in a 2.6 cm miniaturized cylindrical Hall thruster (100 W power level) has been studied through the analysis of experimental data and Monte Carlo simulations of electron dynamics in the thruster channel. The numerical model takes into account elastic and inelastic electron collisions with atoms, electron-wall collisions, including secondary electron emission, and Bohm diffusion. We show that in order to explain the observed discharge current, the electron anomalous collision frequency {nu}{sub B} has to be on the order of the Bohm value, {nu}{sub B} {approx} {omega}{sub c}/16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant.

  13. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Requirements relating to transport indices and criticality safety indices. 176.704 Section 176.704 Transportation Other Regulations Relating to... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport...

  14. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Requirements relating to transport indices and criticality safety indices. 176.704 Section 176.704 Transportation Other Regulations Relating to... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport...

  15. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Requirements relating to transport indices and criticality safety indices. 176.704 Section 176.704 Transportation Other Regulations Relating to... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport...

  16. 49 CFR 176.704 - Requirements relating to transport indices and criticality safety indices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Requirements relating to transport indices and criticality safety indices. 176.704 Section 176.704 Transportation Other Regulations Relating to... Requirements relating to transport indices and criticality safety indices. (a) The sum of the transport...

  17. Transport model based on three-dimensional cross-section generation for TRIGA core analysis

    SciTech Connect

    Kriangchaiporn, N.; Ivanov, K.; Haghighat, A.; Sears, C. F.

    2006-07-01

    The development of a three-dimensional (3-D) transport model for TRIGA core analysis based on the discrete ordinates (S{sub n}) method has been conducted. The effective fine- and broad- group structures for the TRIGA cross-section libraries were selected based on CPXSD (Contribution and Point-wise Cross-Section Driven) methodology. Different 3-D pin/core configurations are used to verify and validate the selected effective group structures. Thirteen-group structure was finally selected to be used for core analysis. The results agree with continuous energy cross-section Monte Carlo calculations for eigenvalues and normalized pin power distributions, which are used as a reference in this research. (authors)

  18. Is Mild Dementia Related to Unsafe Street-Crossing Decisions?

    PubMed

    Dommes, Aurélie; Wu, Ya-Huei; Aquino, Jean-Pierre; Pitti-Ferrandi, Hélène; Soleille, Martine; Martineau-Fleury, Sophie; Samson, Michel; Rigaud, Anne-Sophie

    2015-01-01

    The overrepresentation of very old people (75 or older) in pedestrian crash statistics raises the issue of the effects of normal and pathologic ageing on gap-selection difficulties during street crossing. The present study focused on Alzheimer disease, a condition commonly associated with cognitive declines detrimental to daily life activities such as crossing the street. Twenty-five participants with mild dementia and 33 controls carried out a street-crossing task in a simulated environment. They also took a battery of cognitive tests. The mild-dementia group was more likely than the control group to make decisions that led to collisions with approaching cars, especially when the traffic was coming from 2 directions and they were in the far lane. Regression analyses demonstrated that the increased likelihood of collisions in the dementia group was associated with impairments in processing-speed and visual-attention abilities assessed on the Useful Field of View test. This test has already proven useful for predicting driving outcomes, falls, and street-crossing difficulties in healthy old adults, and among drivers with Alzheimer disease. Clinicians are encouraged to use it to help estimate whether a patient can drive, walk, and cross a street safely. PMID:25494367

  19. Inhomogeneous transport and derivative relations in the quantum Hall regime

    NASA Astrophysics Data System (ADS)

    Simon, Steven H.

    1998-12-01

    Several derivative relations have been observed in the quantum Hall regime including a relation between elements of the macroscopic resistivity tensor Rxx= αB(d Rxy/d B), a relation between elements of the macroscopic thermopower tensor Syx= αB(d Sxx/d B), as well as a similar relation observed in acoustoelectric experiments (here B is the magnetic field and α is a constant). It has been proposed in a number of recent works by the author and collaborators that these relations can be explained with a model of classical transport in an inhomogeneous medium. We review these works and briefly discuss to what extent the models which predict these derivative relations are appropriate for describing the experimental systems.

  20. Generation of discrete scattering cross sections and demonstration of Monte Carlo charged particle transport in the Milagro IMC code package

    SciTech Connect

    Walsh, J. A.; Palmer, T. S.; Urbatsch, T. J.

    2013-07-01

    A new method for generating discrete scattering cross sections to be used in charged particle transport calculations is investigated. The method of data generation is presented and compared to current methods for obtaining discrete cross sections. The new, more generalized approach allows greater flexibility in choosing a cross section model from which to derive discrete values. Cross section data generated with the new method is verified through a comparison with discrete data obtained with an existing method. Additionally, a charged particle transport capability is demonstrated in the time-dependent Implicit Monte Carlo radiative transfer code package, Milagro. The implementation of this capability is verified using test problems with analytic solutions as well as a comparison of electron dose-depth profiles calculated with Milagro and an already-established electron transport code. An initial investigation of a preliminary integration of the discrete cross section generation method with the new charged particle transport capability in Milagro is also presented. (authors)

  1. Disulfide Cross-linking of a Multidrug and Toxic Compound Extrusion Transporter Impacts Multidrug Efflux.

    PubMed

    Radchenko, Martha; Nie, Rongxin; Lu, Min

    2016-04-29

    Multidrug and toxic compound extrusion (MATE) transporters contribute to multidrug resistance by extruding different drugs across cell membranes. The MATE transporters alternate between their extracellular and intracellular facing conformations to propel drug export, but how these structural changes occur is unclear. Here we combine site-specific cross-linking and functional studies to probe the movement of transmembrane helices in NorM from Neiserria gonorrheae (NorM-NG), a MATE transporter with known extracellular facing structure. We generated an active, cysteine-less NorM-NG and conducted pairwise cysteine mutagenesis on this variant. We found that copper phenanthroline catalyzed disulfide bond formation within five cysteine pairs and increased the electrophoretic mobility of the corresponding mutants. Furthermore, copper phenanthroline abolished the activity of the five paired cysteine mutants, suggesting that these substituted amino acids come in spatial proximity during transport, and the proximity changes are functionally indispensable. Our data also implied that the substrate-binding transmembrane helices move up to 10 Å in NorM-NG during transport and afforded distance restraints for modeling the intracellular facing transporter, thereby casting new light on the underlying mechanism. PMID:26975373

  2. Pyschosocial factors associated with children's cycling for transport: A cross-sectional moderation study.

    PubMed

    Ghekiere, Ariane; Van Cauwenberg, Jelle; Carver, Alison; Mertens, Lieze; de Geus, Bas; Clarys, Peter; Cardon, Greet; De Bourdeaudhuij, Ilse; Deforche, Benedicte

    2016-05-01

    Promoting children's cycling for transport is a useful strategy to increase their physical activity levels. No studies have examined to which extent children's psychosocial characteristics play a role in their transportation cycling. Furthermore, insights into the association between children's independent mobility (IM) and transportation cycling is lacking in Europe. This study examined (1) the association of children's psychosocial characteristics with transportation cycling and its moderating effect of child's gender, parents' educational attainment and IM, and (2) the association between children's IM and transportation cycling. Children (n=1232, aged 10-12yrs) completed an online questionnaire at school assessing their psychosocial characteristics related with transportation cycling. Parents reported child's usual transportation cycling and the distance their child is allowed to cycle unsupervised (IM). Hurdle models were used to estimate associations between independent variables and odds of being a cyclist and with minutes of transportation cycling among those cycling. Data were collected during November-December 2014 across Flanders, Belgium. Children's perceived parental modeling, parental norm, peers' co-participation, self-efficacy and IM were positively related to the odds of being a cyclist, perceived benefits were negatively associated. Parental modeling, siblings' modeling, self-efficacy and parental norm were more strongly related to the odds of being a cyclist among children with a low IM. Friends' modeling was significantly related with odds of being a cyclist among boys. IM and parental norm (only among boys) were positively related to the time spent cycling. Targeting children, their friends and parents seems therefore most appropriate when aiming to increase children's transportation cycling. PMID:26968778

  3. Simulation of Large Parallel Plasma Flows in the Tokamak SOL Driven by Cross-Field Transport Asymmetries

    SciTech Connect

    Pigarov, A Y; Krasheninnikov, S I; LaBombard, B; Rognlien, T D

    2006-06-06

    Large-Mach-number parallel plasma flows in the single-null SOL of different tokamaks are simulated with multi-fluid transport code UEDGE. The key role of poloidal asymmetry of cross-field plasma transport as the driving mechanism for such flows is discussed. The impact of ballooning-like diffusive and convective transport and plasma flows on divertor detachment, material migration, impurity flows, and erosion/deposition profiles is studied. The results on well-balanced double null plasma modeling that are indicative of strong asymmetry of cross-field transport are presented.

  4. How Space Radiation Risk from Galactic Cosmic Rays at the International Space Station Relates to Nuclear Cross Sections

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei; Adams, J. H., Jr.

    2005-01-01

    Space radiation risk to astronauts is a major obstacle for long term human space explorations. Space radiation transport codes have thus been developed to evaluate radiation effects at the International Space Station (ISS) and in missions to the Moon or Mars. We study how nuclear fragmentation processes in such radiation transport affect predictions on the radiation risk from galactic cosmic rays. Taking into account effects of the geomagnetic field on the cosmic ray spectra, we investigate the effects of fragmentation cross sections at different energies on the radiation risk (represented by dose-equivalent) from galactic cosmic rays behind typical spacecraft materials. These results tell us how the radiation risk at the ISS is related to nuclear cross sections at different energies, and consequently how to most efficiently reduce the physical uncertainty in our predictions on the radiation risk at the ISS.

  5. Solute Transport in Cyclically Deformed Porous Tissue Scaffolds with Controlled Pore Cross-Sectional Geometries

    PubMed Central

    Op Den Buijs, Jorn; Lu, Lichun; Jorgensen, Steven M.; Dragomir-Daescu, Dan; Yaszemski, Michael J.

    2009-01-01

    The objective of this study was to investigate the influence of pore geometry on the transport rate and depth after repetitive mechanical deformation of porous scaffolds for tissue engineering applications. Flexible cubic imaging phantoms with pores in the shape of a circular cylinder, elliptic cylinder, and spheroid were fabricated from a biodegradable polymer blend using a combined 3D printing and injection molding technique. The specimens were immersed in fluid and loaded with a solution of a radiopaque solute. The solute distribution was quantified by recording 20 μm pixel-resolution images in an X-ray microimaging scanner at selected time points after intervals of dynamic straining with a mean strain of 8.6 ± 1.6% at 1.0 Hz. The results show that application of cyclic strain significantly increases the rate and depth of solute transport, as compared to diffusive transport alone, for all pore shapes. In addition, pore shape, pore size, and the orientation of the pore cross-sectional asymmetry with respect to the direction of strain greatly influence solute transport. Thus, pore geometry can be tailored to increase transport rates and depths in cyclically deformed scaffolds, which is of utmost importance when thick, metabolically functional tissues are to be engineered. PMID:19196145

  6. Physical Modeling of the Cross-Shore Sediment Transport on a Sand-Gravel Beach

    NASA Astrophysics Data System (ADS)

    Xharde, Regis; Brunelle, Corinne; Frandsen, Jannette

    2014-11-01

    The aim of the study is to investigate the cross-shore evolution of a nourished beach profile under storm wave conditions with specific emphasis on sediment transport within the breaking zone. To investigate the underlying mechanisms of the coastal transport processes, a physical model of the beach was built at scale 1:3 in the new Quebec Coastal Physics Laboratory (QCPL), Canada. The modeled beach is 4.2 m high, 5 m wide and 40 m long with a mean slope of 1:10. The beach is formed of a mixture of sediment with grain sizes ranging from 0.65 mm up to 20 mm. The stability of the beach is tested for operational and storm waves. We report on run-up and run-down processes via wave gages, video records of waves and ultrasonic water level measurements. Sediment transport processes within the surf zone and on the beach face are monitored using acoustic Doppler profilers and optical backscattering sensors. The beach profile is surveyed prior and after each test series using a topographic laser scanner. Initial results show that sand is transported off-shore to a breaker bar while cobbles are pushed on the upper beach by run-up. Details of the underlying mechanism of different breaker types and impact on sediment transport will be presented.

  7. Transport of cross helicity and the radial evolution of Alfvenicity in the solar wind

    NASA Astrophysics Data System (ADS)

    Matthaeus, W. H.; Minnie, J.; Breech, B.; Parhi, S.; Bieber, J. W.; Oughton, S.; Bavassano, B.

    2004-05-01

    A transport theory for cross helicity is described, including both scale-separated spatial transport and a phenomenological description of nonlinear effects associated with magnetohydrodynamic turbulence. The formalism is applied to the radial evolution of the solar wind, where driving effects of shear and pickup ions are included. It is found that the radial decrease of cross helicity observed in the equatorial solar wind can be accounted for when sufficient driving is included to overcome dynamic alignment, i.e., the inherent tendency for MHD turbulence to produce Alfvenic states. For the high latitude wind, which evolves under influence of a lower mean shear stregnth, the theory predicts a closer balance between dynamic alignment and shear strength effects, so that the normalized cross helicity, which generally decreases with increasing heliocentric radial distance, changes very little between 2 and 4 AU. This accounts well for Ulysses observations. This research supported in part by NSF grant TM-0105254, NASA grants NAG5-8134, NAG5-11603, NAG5-6570 and NAG5-10911, and the NZ Marsden Fund (02-UOW-050 MIS).

  8. Sulfadimethoxine transport in soil columns in relation to sorbable and non-sorbable tracers.

    PubMed

    Park, Jong Yol; Huwe, Bernd

    2016-06-01

    In this study, miscible displacement experiment and batch sorption experiments were performed with sulfadimethoxine, dye tracer, Brilliant Blue FCF (BB) and a conservative tracer (bromide) to depict, analyse and interpret transport paths of sulfadimethoxine in undisturbed and disturbed soil columns. Batch sorption experiment revealed that sorption potential increased in the order: Brilliant Blue FCF > sulfadimethoxine > bromide. The horizontal spatial patterns of sulfadimethoxine and the tracers were analysed in each depth, and selective samples were taken in horizontal cross-section. Non-adsorbable and conservative tracer, bromide spread more widely into longitudinal and horizontal direction than sulfadimethoxine and Brilliant Blue FCF, since adsorption reduced transversal dispersion of the sulfadimethoxine and dye. In non-stained area, residual concentrations of sulfadimethoxine were relatively lower than in stained areas. Therefore, Brilliant Blue FCF distribution can be used to approximate sulfadimethoxine movement in soil. However, presence of preferential flow networks found in undisturbed soil cores can enhance mobility of sulfadimethoxine and the tracers, due to faster flow velocities and non-equilibrium adsorption. Our findings showed that other dye tracers may also be applicable to identify transport pathways of various organic contaminants, of which physico-chemical properties are similar to those of the dye tracers. Preferential flow should be considered for drinking water managements and transport modelling, since this allows faster pollutants transport from their sources, and create critical consequences for groundwater quality and solute transport modelling. PMID:26983917

  9. Observational Constraints on Atmospheric and Oceanic Cross-Equatorial Heat Transports: Revisiting the Precipitation Asymmetry Problem in Climate Models

    NASA Astrophysics Data System (ADS)

    Loeb, N. G.; Wang, H.; Cheng, A.; Kato, S.; Fasullo, J.; Xu, K. M.; Allan, R. P.

    2015-12-01

    Recent studies have shown strong linkages between hemispheric asymmetries in atmospheric and oceanic energy budgets, tropical precipitation and the mean position of the Intertropical Convergence Zone (ITCZ). The energetics framework has been used to explain why the mean position of the ITCZ is in the Northern Hemisphere and to study large-scale circulation and precipitation responses to changes in the hemispheric distribution of heating. Here, we expand upon these earlier studies by also considering estimates of hemispheric asymmetry in surface and atmospheric radiation budget derived from satellite observations, which enables a decomposition of cross-equatorial heat transport in terms of radiative and non-radiative (i.e., combined latent and sensible heat) components. Satellite observations of top-of-atmosphere (TOA) and surface radiation budget from the Clouds and the Earth's Radiation Budget (CERES) are combined with mass corrected vertically integrated atmospheric energy divergence from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Observed radiative and combined sensible and latent heat contributions to atmospheric and oceanic cross-equatorial heat transports are compared with simulations from 30 models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5). Results show that most CMIP5 models that overestimate tropical precipitation in the SH have too much net downward surface radiation and combined latent and sensible heat flux in the SH relative to the NH. In addition, many of the models also underestimate atmospheric radiative cooling in the SH compared to the NH. Consequently, the models have excessive heating of the SH atmosphere and anomalous SH to NH cross-equatorial heat transport. The anomalous northward heat transport occurs via the upper branch of the northern Hadley Cell, while anomalous NH to SH moisture transport occurs in the lower branch of the northern

  10. Cross-layer restoration with software defined networking based on IP over optical transport networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Cheng, Lei; Deng, Junni; Zhao, Yongli; Zhang, Jie; Lee, Young

    2015-10-01

    The IP over optical transport network is a very promising networking architecture applied to the interconnection of geographically distributed data centers due to the performance guarantee of low delay, huge bandwidth and high reliability at a low cost. It can enable efficient resource utilization and support heterogeneous bandwidth demands in highly-available, cost-effective and energy-effective manner. In case of cross-layer link failure, to ensure a high-level quality of service (QoS) for user request after the failure becomes a research focus. In this paper, we propose a novel cross-layer restoration scheme for data center services with software defined networking based on IP over optical network. The cross-layer restoration scheme can enable joint optimization of IP network and optical network resources, and enhance the data center service restoration responsiveness to the dynamic end-to-end service demands. We quantitatively evaluate the feasibility and performances through the simulation under heavy traffic load scenario in terms of path blocking probability and path restoration latency. Numeric results show that the cross-layer restoration scheme improves the recovery success rate and minimizes the overall recovery time.

  11. 49 CFR 805.735-8 - Employment of family members in transportation and related enterprises.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Employment of family members in transportation and related enterprises. 805.735-8 Section 805.735-8 Transportation Other Regulations Relating to... Employment of family members in transportation and related enterprises. (a) No individual will be employed...

  12. 49 CFR 805.735-8 - Employment of family members in transportation and related enterprises.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Employment of family members in transportation and related enterprises. 805.735-8 Section 805.735-8 Transportation Other Regulations Relating to... Employment of family members in transportation and related enterprises. (a) No individual will be employed...

  13. Volumetric Deformation of Live Cells Induced by Pressure-Activated Cross-Membrane Ion Transport

    NASA Astrophysics Data System (ADS)

    Hui, T. H.; Zhou, Z. L.; Qian, J.; Lin, Y.; Ngan, A. H. W.; Gao, H.

    2014-09-01

    In this work, we developed a method that allows precise control over changes in the size of a cell via hydrostatic pressure changes in the medium. Specifically, we show that a sudden increase, or reduction, in the surrounding pressure, in the physiologically relevant range, triggers cross-membrane fluxes of sodium and potassium ions in leukemia cell lines K562 and HL60, resulting in reversible volumetric deformation with a characteristic time of around 30 min. Interestingly, healthy leukocytes do not respond to pressure shocks, suggesting that the cancer cells may have evolved the ability to adapt to pressure changes in their microenvironment. A model is also proposed to explain the observed cell deformation, which highlights how the apparent viscoelastic response of cells is governed by the microscopic cross-membrane transport.

  14. Anomalous cross-B field transport and spokes in HiPIMS plasma

    NASA Astrophysics Data System (ADS)

    Hecimovic, A.

    2016-05-01

    Localized light emission patterns observed during on time of a high power impulse magnetron sputtering (HiPIMS) discharge on a planar magnetron, known as spokes or ionization zones, have been identified as a potential source of anomalous cross-B field diffusion. In this paper experimental evidence is presented that anomalous diffusion is triggered by the appearance of spokes. The Hall parameter {ω\\text{ce}}{τ\\text{c}} , product of the electron cyclotron frequency and the classical collision time, reduces from Bohm diffusion values (∼ 16 and higher) down to the value of 3 as spokes appear, indicating anomalous cross-B field transport. A combination of intensified charge coupled device imaging and electric probe measurements reveals that the ions from the spokes are instantaneously diffusing away from the target. The ion diffusion coefficients calculated from a sideways image of the spoke are six times higher than Bohm diffusion coefficients, which is consistent with the reduction of the Hall parameter.

  15. Experimental verification of reciprocity relations in quantum thermoelectric transport

    NASA Astrophysics Data System (ADS)

    Matthews, J.; Battista, F.; Sánchez, D.; Samuelsson, P.; Linke, H.

    2014-10-01

    Fundamental symmetries in thermoelectric quantum transport, beyond Onsagers relations, were predicted two decades ago but have to date not been observed in experiments. Recent works have predicted the symmetries to be sensitive to energy-dependent, inelastic scattering, raising the question whether they exist in practice. Here, we answer this question affirmatively by experimentally verifying the thermoelectric reciprocity relations in a four-terminal mesoscopic device where each terminal can be electrically and thermally biased individually. The linear-response thermoelectric coefficients are found to be symmetric under simultaneous reversal of magnetic field and exchange of injection and emission contacts. We also demonstrate a controllable breakdown of the reciprocity relations by increasing thermal bias, putting in prospect enhanced thermoelectric performance.

  16. Cross-Field Electron Heat Transport in a Magnetoplasma, in the Presence of Ion Turbulence

    NASA Astrophysics Data System (ADS)

    Needelman, David Dore

    Cross-field heat transport through a cylindrical pulsed argon afterglow magnetoplasma, (B_0 = 48-300G, rm T_{e} ~ 0.5-7 eV, n_{e} ~ 10^{11} cm^{ -3}, Phi_{s } ~ 2V, radius = 5 cm), is investigated. The study of heat flow is relevant to the fields of fusion engineering and space physics. A BaO-coated dispenser cathode is used to produce a pulsed electron beam, (V_{b}=750 V, I_{b} = 1A, radius = 1.27 cm, tau_{b} = 5 - 10mus, fired 300 mus into the afterglow), propagating down the central axis of the plasma. The beam heats the background electrons within some centimeters of the beam launching point (Whe85); heat diffuses along field lines, forming a "flux tube" of hot plasma. Biased grids, (radius = 5 cm, V_{g} = -200V), are used to retard the axial heat flow through the tube. A radially inserted Langmuir probe is used to map T_{e}, n_ {e}, and Phi_{s } as a function of position and time. There profiles are used to deduce the electron cross-field thermal conductivity coefficient, kappa_| . Anomalous heat transport is found for all cases studied; kappa_| is found to be up to two orders of magnitude above classical predictions. Such transport is attributed to quasilinear effects; collisions of the background electrons with radial ion acoustic waves created indirectly by the beam, through action of the beam/plasma and oscillating two-stream instabilities (Whe85), and with azimuthal ion acoustic waves, created by the pressure-gradient instability(All74). An enhanced collision frequency leads to faster cross-field particle and heat diffusion. Measurements of wave amplitudes are presented, as are correlation measurements proving the waves are ion acoustic. Comparisons of experimental measurements with quasilinear theory predictions (Man78) are shown to be quite close.

  17. Influence of oblique magnetic field on electron cross-field transport in a Hall effect thruster

    SciTech Connect

    Miedzik, Jan; Daniłko, Dariusz; Barral, Serge

    2015-04-15

    The effects of the inclination of the magnetic field with respect to the channel walls in a Hall effect thruster are numerically studied with the use of a one-dimensional quasi-neutral Particle-In-Cell model with guiding center approximation of electron motion along magnetic lines. Parametric studies suggest that the incidence angle strongly influences electron transport across the magnetic field. In ion-focusing magnetic topologies, electrons collide predominantly on the side of the magnetic flux tube closer to the anode, thus increasing the electron cross-field drift. The opposite effect is observed in ion-defocussing topology.

  18. Influence of oblique magnetic field on electron cross-field transport in a Hall effect thruster

    NASA Astrophysics Data System (ADS)

    Miedzik, Jan; Barral, Serge; Daniłko, Dariusz

    2015-04-01

    The effects of the inclination of the magnetic field with respect to the channel walls in a Hall effect thruster are numerically studied with the use of a one-dimensional quasi-neutral Particle-In-Cell model with guiding center approximation of electron motion along magnetic lines. Parametric studies suggest that the incidence angle strongly influences electron transport across the magnetic field. In ion-focusing magnetic topologies, electrons collide predominantly on the side of the magnetic flux tube closer to the anode, thus increasing the electron cross-field drift. The opposite effect is observed in ion-defocussing topology.

  19. Evidence for enhanced cross-field transport mechanisms in the TCV Snowflake divertor

    NASA Astrophysics Data System (ADS)

    Vijvers, Wouter

    2015-11-01

    TCV experiments demonstrate that cross-field plasma transport is enhanced in the Snowflake divertor (SFD) compared to a standard single-null divertor (SND). This enhanced cross-field transport spreads the exhaust power over a larger surface area than can be achieved by magnetic geometry alone and, thereby, reduces the peak heat flux. Comparison of the experiments with modelling identifies steepened radial gradients, ExB drift effects, and βp-driven instabilities as the responsible transport mechanisms. The uncovered physics is also relevant to the SND and may help improve predictive models for the target profiles in ITER and DEMO. In SFD variants with an X-point in the scrape-off layer (SOL), part of the heat flux profile is split off and redirected to an additional target. The resulting steepened radial gradients enhance cross-field diffusion. This is confirmed by EMC3-Eirene simulations, which show a factor two reduction of the parallel heat flux, even if diffusivities remain constant. Theoretical analysis predicts enhanced ExB drifts in the SFD by increased poloidal gradients of the temperature and density. The predictions are confirmed by target heat and particle flux measurements in dedicated experiments with both toroidal field directions. Cross-field convection by curvature-driven modes at high βp (``churning modes'') explains the large fluxes into the private flux region of the SFD. This activates the extra targets and reduces the peak power to the primary targets up to a factor four. This mechanism is expected to be most effective when the divertor conditions are most severe: near the separatrix of a narrow, high-pressure SOL of a large tokamak. These and other alternative divertor configurations thus provide potential solutions to the power exhaust challenge, as well as laboratories to study SOL transport, one of the most important topics in tokamak research. This project was carried out with financial support from NWO. The work was carried out within

  20. H-N2 interaction energies, transport cross sections, and collision integrals

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Walch, Stephen P.; Levin, Eugene

    1992-01-01

    The energies for the interaction of a hydrogen atom with a nitrogen molecule have been calculated for large separation distances using a complete-active-space self-consistent-field/externally contracted configuration interaction method. H-N2 transport cross sections and collision integrals have been calculated using sudden approximations and a semiclassical description of the scattering. The values of these quantities are found to be close to the corresponding values determined from the average (isotropic) potential energy. The collision integrals are applied to determine diffusion and viscosity coefficients; the theoretical diffusion agrees well with the measured data available from experiments at low temperatures.

  1. Electron Cross-field Transport in a Miniaturized Cylindrical Hall Thruster

    SciTech Connect

    Smirnov Artem, Raitses Yevgeny, Fisch Nathaniel J

    2005-10-14

    Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. The present paper gives a review of the experimental and numerical investigations of electron crossfield transport in the 2.6 cm miniaturized cylindrical Hall thruster (100 W power level). We show that, in order to explain the discharge current observed for the typical operating conditions, the electron anomalous collision frequency {nu}{sub b} has to be on the order of the Bohm value, {nu}{sub B} {approx} {omega}{sub c}/16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant. The optimal regimes of thruster operation at low background pressure (below 10{sup -5} Torr) in the vacuum tank appear to be different from those at higher pressure ({approx} 10{sup -4} Torr).

  2. Is Long-Term Coastline Evolution Independent of Large-Scale Cross-Shore Transport?

    NASA Astrophysics Data System (ADS)

    Worman, S.; Murray, A.; Limber, P. W.

    2012-12-01

    Long-term coastal evolution is independent of small-scale cross-shore sediment transport: Winds and currents associated with storms and seasons temporarily divert sand off-shore but waves quickly swept it back [List and Farris, 1999]. Large-scale (kms and greater) chronic shoreline change is, instead, driven by gradients in along-shore sediment transport [Lazarus and Murray 2007, Lazarus et al. 2011]. However large-scale planform features, whether emergent or geologically determined, channel large volumes of sand across shore. On sandy coastlines, for instance, capes produce a hydrodynamic confluence and build shoals whereas on rocky coastlines, near-shore canyons intercept and flush sediment into the abyss. The impressive size of offshore shoals and submarine deltas suggests that these spatially discrete locations are large sediment sinks, functioning as dramatic one-way cross-shore transport conduits. Using a numerical model of large-scale shoreline change, we explore the connection between these features and retreat rates in both sandy and rocky coastlines. By locally disrupting gradients in along-shore sediment transport set up by wave characteristics and shoreline orientation, our preliminary results suggest that these large-scale sinks exert a currently unexplored first-order control on coastal planform morphology and evolution. References List, J.H., and A.S. Farris: Large-Scale Shoreline Response to Storms and Fair Weather. 1999. Coastal Sediments, 1-3:1324-1338. Lazarus, E.D and A.B. Murray. 2007. Process Signatures in Regional Patterns of Shoreline Change on Annual to Decadal Time Scales. Geophysical Research Letters, 34, 19. Lazarus, E.D., A. Ashton, A.B. Murray, S. Tebbens, and S. Burroughs. 2011. Cumulative Versus Transient Shoreline Change: Dependencies on Temporal and Spatial Scale. Journal of Geophysical Research - Earth Surface, 116.

  3. Off-Highway Transportation-Related Fuel Use

    SciTech Connect

    Davis, S.C.

    2004-05-08

    The transportation sector includes many subcategories--for example, on-highway, off-highway, and non-highway. Use of fuel for off-highway purposes is not well documented, nor is the number of off-highway vehicles. The number of and fuel usage for on-highway and aviation, marine, and rail categories are much better documented than for off-highway land-based use. Several sources document off-highway fuel use under specific conditions--such as use by application (e.g., recreation) or by fuel type (e.g., gasoline). There is, however, no single source that documents the total fuel used off-highway and the number of vehicles that use the fuel. This report estimates the fuel usage and number of vehicles/equipment for the off-highway category. No new data have been collected nor new models developed to estimate the off-highway data--this study is limited in scope to using data that already exist. In this report, unless they are being quoted from a source that uses different terminology, the terms are used as listed below. (1) ''On-highway/on-road'' includes land-based transport used on the highway system or other paved roadways. (2) ''Off-highway/off-road'' includes land-based transport not using the highway system or other paved roadways. (3) ''Non-highway/non-road'' includes other modes not traveling on highways such as aviation, marine, and rail. It should be noted that the term ''transportation'' as used in this study is not typical. Generally, ''transportation'' is understood to mean the movement of people or goods from one point to another. Some of the off-highway equipment included in this study doesn't transport either people or goods, but it has utility in movement (e.g., a forklift or a lawn mower). Along these lines, a chain saw also has utility in movement, but it cannot transport itself (i.e., it must be carried) because it does not have wheels. Therefore, to estimate the transportation-related fuel used off-highway, transportation equipment is defined to

  4. Effective Potential Energies and Transport Cross Sections for Interactions of Hydrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, James R. (Technical Monitor)

    2000-01-01

    The interaction energies for N2-He and N2-H2 are calculated by accurate ab initio methods. The virial coefficient and differential scattering cross section for N2-H2 are calculated; the theoretical results are compared with experimental data. The transport collision integrals for N2-H2 and N2-N2 interactions are calculated and tabulated; the results yield transport coefficients that compare well with measured data. Transport coefficients are found to be determined accurately from the interaction energies for a specific configuration of the molecule formed from the interaction partners. Comparisons with results of measurement and accurate calculations demonstrate that the transport properties of complex molecular interactions can be determined rapidly and fairly accurately from the interaction energies of simpler system using combination rules for the short-range parameters of effective interaction energies and the coefficients for the long-range forces. The coefficients for a two-parameter temperature expansion of diffusion and viscosity are tabulated for a realistic universal potential energy that is based primarily on the results of very accurate calculations of the He-He interaction energy.

  5. Cross-frontal transport along the Keweenaw coast in Lake Superior: a Lagrangian model study

    NASA Astrophysics Data System (ADS)

    Chen, Changsheng; Zhu, Jianrong; Kang, KiRyong; Liu, Hedong; Ralph, Elise; Green, Sarah A.; Budd, Judith Wells

    2002-11-01

    Offshore transport across the thermal front along the Keweenaw coast in Lake Superior was examined by tracking the trajectories of water particles in the model-simulated three-dimensional (3D) flow field of July 1973. Particles were released at different depths and horizontal locations within the Keweenaw Current during various wind events and were tracked until the end of the month. The trajectories of water particles showed a remarkable offshore cross-frontal water transport at the topographic-splitting point on the eastern side of the Keweenaw Waterway and near Eagle Harbor. This transport was driven dominantly by wind-induced Ekman flow near the surface but was controlled by local bottom topography in the deep region. A northeastward wind prevailed over the lake during July 1973. This wind tended to produce onshore water transports near the surface and hence caused downwelling against the coast. An offshore current was expected in the deep region based on the conservation of water mass. The vortex shedding off coastal bathymetry abutments plus baroclinic instability of the thermal front also led to offshore meandering of the temperature field in the deep region over local varying bottom topography. This meandering tended to produce a cyclonic vorticity and drove particles offshore across the thermal front along the northern coast of the Keweenaw Peninsula.

  6. Mitochondrial transporters for ornithine and related amino acids: a review.

    PubMed

    Monné, Magnus; Miniero, Daniela Valeria; Daddabbo, Lucia; Palmieri, Luigi; Porcelli, Vito; Palmieri, Ferdinando

    2015-09-01

    Among the members of the mitochondrial carrier family, there are transporters that catalyze the translocation of ornithine and related substrates, such as arginine, homoarginine, lysine, histidine, and citrulline, across the inner mitochondrial membrane. The mitochondrial carriers ORC1, ORC2, and SLC25A29 from Homo sapiens, BAC1 and BAC2 from Arabidopsis thaliana, and Ort1p from Saccharomyces cerevisiae have been biochemically characterized by transport assays in liposomes. All of them transport ornithine and amino acids with side chains terminating at least with one amine. There are, however, marked differences in their substrate specificities including their affinity for ornithine (KM values in the mM to μM range). These differences are most likely reflected by minor differences in the substrate binding sites of these carriers. The physiological role of the above-mentioned mitochondrial carriers is to link several metabolic pathways that take place partly in the cytosol and partly in the mitochondrial matrix and to provide basic amino acids for mitochondrial translation. In the liver, human ORC1 catalyzes the citrulline/ornithine exchange across the mitochondrial inner membrane, which is required for the urea cycle. Human ORC1, ORC2, and SLC25A29 are likely to be involved in the biosynthesis and transport of arginine, which can be used as a precursor for the synthesis of NO, agmatine, polyamines, creatine, glutamine, glutamate, and proline, as well as in the degradation of basic amino acids. BAC1 and BAC2 are implicated in some processes similar to those of their human counterparts and in nitrogen and amino acid metabolism linked to stress conditions and the development of plants. Ort1p is involved in the biosynthesis of arginine and polyamines in yeast. PMID:26002808

  7. Spin Related Transport in Rashba 2DEG Systems

    NASA Astrophysics Data System (ADS)

    Nitta, Junsaku

    Transport in mesoscopic conductors is determined not only by orbital motion of carriers but also by quantum interference effect. However, it is well known that the quantum interference such as weak localization is much modified in the presence of spin-orbit interaction (SOI), leading to weak anti-localization. We discuss the origin of the Rashba SOI and spin related mesoscopic transport in InGaAs based two dimensional electron gases (2DEG) affected by the Rashba SOI. It is experimentally shown that the strength of the Rashba SOI in InGaAs 2DEG systems can be controlled by the gate voltage.1 The spin dynamics in solid systems is commonly determined by the competition between Zeeman effect and SOI. The spin relaxation time and dephasing time are studied from weak anti-localization analysis as a function of the relative strength of the Zeeman energy (EZ) and the Rashba SOI energy (ESOI). The (EZ) was introduced by applying magnetic field parallel to the 2DEG plane. This in-pane magnetic field does not affect the orbital motion of electrons. The spin relaxation time increases with the Zeeman energy. The dephasing time associated with the spin-induced time reversal symmetry (TRS) breaking saturates when EZ becomes comparable to ESOI. Moreover, we show that the spin-induced TRS breaking mechanism is a universal function of the ratio EZ/ESOI within the experimental accuracy.2 Note from Publisher: This article contains the abstract only.

  8. Using Source Apportionment to Evaluate the Cross State Transport of Ozone in the Eastern United States

    NASA Astrophysics Data System (ADS)

    Goldberg, D. L.; Canty, T. P.; Hembeck, L.; Vinciguerra, T.; Carpenter, S. F.; Anderson, D. C.; Salawitch, R. J.; Dickerson, R. R.

    2014-12-01

    The amount of air pollution crossing state lines has great policy implications. Using the ozone source apportionment tool (OSAT) in the Comprehensive Air-Quality Model with Extensions (CAMx) version 6.10, we can quantify how much ozone is generated locally versus transported from upwind locations. Initial results show that up to 70% of the surface ozone in Maryland during poor air quality days in the summer of July 2011 can be attributed to pollution from outside of the state's borders. Modifications to the CB05 gas-phase chemistry mechanism, supported by literature recommendations and improve agreement with NASA's DISCOVER-AQ Maryland aircraft campaign, can further increase this percentage. Additionally, we show the role of upwind sources and background ozone has become increasingly important as local emissions of ozone precursors continue to drop, starting with the steep reductions imposed in 2002 in response to Maryland's State Implementation Plan submitted to EPA. This study suggests future efforts to control surface ozone must include a meaningful strategy for dealing with cross-state transport of ozone precursors.

  9. Object relations and real life relationships: a cross method assessment.

    PubMed

    Handelzalts, Jonathan E; Fisher, Shimrit; Naot, Rachel

    2014-04-01

    This study examines the relationship between the psychoanalytic concept of object relations and real life behavior of being in an intimate relationship among heterosexual women. In a multi-method approach we used two different measures; the self-report Bell Object Relations and Reality Testing Inventory (BORRTI; Bell, Billington & Becker, 1986) and the performance based Thematic Apperception Test (TAT) Social Cognition & Object Relations Scale- Global Rating Method SCORS-G (Westen, 1995) to measure the object relations of 60 women. The Alienation subscale of the BORRTI and understanding of social causality subscale of the SCORS-G explained 34.8% of variance of the intimate relationship variable. Thus, women involved in a romantic relationship reported lower rates of alienation on the BORRTI and produced TAT narratives that were more adaptive with regard to understanding of social causality as measured by the SCORS-G than those not currently in a relationship. Results are discussed with reference to the relationship between object relations and real life measures of healthy individuals and in light of the need for a multi-method approach of assessment. PMID:24506278

  10. Relative Angle-Differential Cross Sections for Elastic Electron Scattering from Pyrimidine

    NASA Astrophysics Data System (ADS)

    Maljkovic, J. B.; Milosavljevic, A. R.; Sevic, D.; Marinkovic, B. P.

    2008-07-01

    Angle-differential cross sections for elastic scattering of electrons from pyrimidine are reported for the incident energies from 50-300 eV. Measurements were performed using a cross-beam technique, for scattering angles from 20^o to 110^o. Experimental relative elastic differential cross sections are compared with recent theoretical results for uracil, which is a pyrimidine base and a component of ribonucleic acid.

  11. Direct relations between morphology and transport in Boolean models.

    PubMed

    Scholz, Christian; Wirner, Frank; Klatt, Michael A; Hirneise, Daniel; Schröder-Turk, Gerd E; Mecke, Klaus; Bechinger, Clemens

    2015-10-01

    We study the relation of permeability and morphology for porous structures composed of randomly placed overlapping circular or elliptical grains, so-called Boolean models. Microfluidic experiments and lattice Boltzmann simulations allow us to evaluate a power-law relation between the Euler characteristic of the conducting phase and its permeability. Moreover, this relation is so far only directly applicable to structures composed of overlapping grains where the grain density is known a priori. We develop a generalization to arbitrary structures modeled by Boolean models and characterized by Minkowski functionals. This generalization works well for the permeability of the void phase in systems with overlapping grains, but systematic deviations are found if the grain phase is transporting the fluid. In the latter case our analysis reveals a significant dependence on the spatial discretization of the porous structure, in particular the occurrence of single isolated pixels. To link the results to percolation theory we performed Monte Carlo simulations of the Euler characteristic of the open cluster, which reveals different regimes of applicability for our permeability-morphology relations close to and far away from the percolation threshold. PMID:26565348

  12. Direct relations between morphology and transport in Boolean models

    NASA Astrophysics Data System (ADS)

    Scholz, Christian; Wirner, Frank; Klatt, Michael A.; Hirneise, Daniel; Schröder-Turk, Gerd E.; Mecke, Klaus; Bechinger, Clemens

    2015-10-01

    We study the relation of permeability and morphology for porous structures composed of randomly placed overlapping circular or elliptical grains, so-called Boolean models. Microfluidic experiments and lattice Boltzmann simulations allow us to evaluate a power-law relation between the Euler characteristic of the conducting phase and its permeability. Moreover, this relation is so far only directly applicable to structures composed of overlapping grains where the grain density is known a priori. We develop a generalization to arbitrary structures modeled by Boolean models and characterized by Minkowski functionals. This generalization works well for the permeability of the void phase in systems with overlapping grains, but systematic deviations are found if the grain phase is transporting the fluid. In the latter case our analysis reveals a significant dependence on the spatial discretization of the porous structure, in particular the occurrence of single isolated pixels. To link the results to percolation theory we performed Monte Carlo simulations of the Euler characteristic of the open cluster, which reveals different regimes of applicability for our permeability-morphology relations close to and far away from the percolation threshold.

  13. Cross-field electron transport induced by a rotating spoke in a cylindrical Hall thruster

    SciTech Connect

    Ellison, C. L.; Raitses, Y.; Fisch, N. J.

    2012-01-15

    Rotating spoke phenomena have been observed in a variety of Hall thruster and other E x B devices. It has been suggested that the spoke may be associated with the enhancement of the electron cross-field transport. In this paper, the current conducted across the magnetic field via a rotating spoke has been directly measured for the first time in the E x B discharge of a cylindrical Hall thruster. The spoke current was measured using a segmented anode. Synchronized measurements with a high speed camera and a four-segment anode allow observation of the current as a function of time and azimuthal position. Upwards of 50% of the total current is conducted through the spoke, which occupies a quarter of the Hall thruster channel area. To determine the transport mechanism, emissive and Langmuir probes were installed to measure fluctuating plasma potential, electron density, and temperature. A perturbed, azimuthal electric field and density are observed to oscillate in-phase with the rotating spoke. The resulting drift current is found to enhance electron transport with a magnitude equal to the spoke current to within margins of error.

  14. Effects of Anomalous Electron Cross-Field Transport in a Low Temperature Magnetized Plasma

    NASA Astrophysics Data System (ADS)

    Raitses, Yevgeny

    2014-10-01

    The application of the magnetic field in a low pressure plasma can cause a spatial separation of low and high energy electrons. This so-called magnetic filter effect is used for many plasma applications, including ion and neutral beam sources, plasma processing of semiconductors and nanomaterials, and plasma thrusters. In spite of successful practical applications, the magnetic filter effect is not well understood. In this work, we explore this effect by characterizing the electron and ion energy distribution functions in a plasma column with crossed electric and magnetic fields. Experimental results revealed a strong dependence of spatial variations of plasma properties on the gas pressure. For xenon and argon gases, below ~ 1 mtorr, the increase of the magnetic field leads to a more uniform profile of the electron temperature. This surprising result is due to anomalously high electron cross-field transport that causes mixing of hot and cold electrons. High-speed imaging and probe measurements revealed a coherent structure rotating in E cross B direction with frequency of a few kHz. Theory and simulations describing this rotating structure has been developed and points to ionization and electrostatic instabilities as their possible cause. Similar to spoke oscillations reported for Hall thrusters, this rotating structure conducts the large fraction of the cross-field current. The use of segmented electrodes with an electrical feedback control is shown to mitigate these oscillations. Finally, a new feature of the spoke phenomenon that has been discovered, namely a sensitive dependence of the rotating oscillations on the gas pressure, can be important for many applications. This work was supported by DOE Contract DE-AC02-09CH11466.

  15. Sudden clearing of estuarine waters upon crossing the threshold from transport to supply regulation of sediment transport as an erodible sediment pool is depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, David H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991–1998 to 1999–2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing.

  16. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  17. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  18. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  19. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money... SANCTIONS REGULATIONS Prohibitions § 538.209 Prohibited transportation-related transactions involving Sudan... relating to transportation of cargo to or from Sudan; (b) The provision of transportation of cargo to...

  20. Kelvin-Helmholtz vortex formation and particle transport in a cross-field plasma sheath

    SciTech Connect

    Theilhaber, K.; Birdsall, C.K.

    1989-02-13

    The time-dependent behavior of a magnetized, two-dimensional plasma-wall sheath has been studied through particle simulations, whcih have shown that the cross-field sheath develops into a turbulent boundary layer, driven by the Kelvin-Helmholtz instability. The sheath acquires an equilibrium thickness l/sub x/approx.5rho/sub i/, and maintains long-lived vortices, with amplitudes deltaphiapprox.-2T/sub i//e, which drift parallel to the wall at half the ion thermal velocity. A central simulation result is that for ..omega../sub ..pi../greater than or equal to2..omega../sub ci/, the anomalous particle transport in the sheath scales like Bohn diffusion.

  1. Graphene thermal transport studies via radio-frequency, cross-correlated Johnson noise thermometry

    NASA Astrophysics Data System (ADS)

    Crossno, Jesse; Liu, Xiaomeng; Wang, Ke; Harzheim, Achim; Watanabe, Kenji; Taniguchi, Takashi; Ohki, Thomas; Fong, Kin Chung; Kim, Philip

    2015-03-01

    The electronic temperature of a dissipative, mesoscale device can be determined by monitoring the Johnson noise power emitted over a wide frequency range. Using radiometry techniques, we have developed a high-frequency, wide bandwidth, cross-correlation Johnson noise thermometer operating from room temperature to cryogenic levels that is compatible with strong magnetic fields. Precisions ranging from 2 to 25 mK are demonstrated over the temperature range of 3 to 300 K with 1 second of integration time. This non-invasive thermometer has enabled us to perform sensitive electronic thermal transport studies in boron nitride encapsulated monolayer graphene over two orders of magnitude in temperature. This versatile technique also enables precision Fano factor measurements as well as studies of correlated noise phenomena, such as those found in layered Van der Waals heterostructures.

  2. Transportation.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with transportation and energy use. Its objective is for the student to be able to discuss the implication of energy usage as it applies to the area of transportation. Some topics covered are efficiencies of various transportation…

  3. TOPICAL REVIEW: Kinetic phenomena in charged particle transport in gases, swarm parameters and cross section data

    NASA Astrophysics Data System (ADS)

    Petrovic, Z. Lj; Suvakov, M.; Nikitovic, Z.; Dujko, S.; Sasic, O.; Jovanovic, J.; Malovic, G.; Stojanovic, V.

    2007-02-01

    In this review we discuss the current status of the physics of charged particle swarms, mainly electrons. The whole field is analysed mainly through its relationship to plasma modelling and illustrated by some recent examples developed mainly by our group. The measurements of the swarm coefficients and the availability of the data are briefly discussed. More time is devoted to the development of complete electron molecule cross section sets along with recent examples such as NO, CF4 and HBr. We extend the discussion to the availability of ion and fast neutral data and how swarm experiments may serve to provide new data. As a point where new insight into the kinetics of charge particle transport is provided, the role of kinetic phenomena is discussed and recent examples are listed. We focus here on giving two examples on how non-conservative processes make dramatic effects in transport, the negative absolute mobility and the negative differential conductivity for positrons in argon. Finally we discuss the applicability of swarm data in plasma modelling and the relationship to other fields where swarm experiments and analysis make significant contributions. Based on the general invited lecture presented by the first author at ESCAMPIG 2006 at Lecce in Italy.

  4. Diffusion, transport, and cell membrane organization investigated by imaging fluorescence cross-correlation spectroscopy.

    PubMed

    Sankaran, Jagadish; Manna, Manoj; Guo, Lin; Kraut, Rachel; Wohland, Thorsten

    2009-11-01

    Cell membrane organization is dynamic and is assumed to have different characteristic length scales. These length scales, which are influenced by lipid and protein composition as well as by the cytoskeleton, can range from below the optical resolution limit (as with rafts or microdomains) to far above the resolution limit (as with capping phenomena or the formation of lipid "platforms"). The measurement of these membrane features poses a significant problem because membrane dynamics are on the millisecond timescale and are thus beyond the time resolution of conventional imaging approaches. Fluorescence correlation spectroscopy (FCS), a widely used spectroscopic technique to measure membrane dynamics, has the required time resolution but lacks imaging capabilities. A promising solution is the recently introduced method known as imaging total internal reflection (ITIR)-FCS, which can probe diffusion phenomena in lipid membranes with good temporal and spatial resolution. In this work, we extend ITIR-FCS to perform ITIR fluorescence cross-correlation spectroscopy (ITIR-FCCS) between pixel areas of arbitrary shape and derive a generalized expression that is applicable to active transport and diffusion. ITIR-FCCS is applied to model systems exhibiting diffusion, active transport, or a combination of the two. To demonstrate its applicability to live cells, we observe the diffusion of a marker, the sphingolipid-binding domain (SBD) derived from the amyloid peptide Abeta, on live neuroblastoma cells. We investigate the organization and dynamics of SBD-bound lipid microdomains under the conditions of cholesterol removal and cytoskeleton disruption. PMID:19883607

  5. Ticagrelor Does Not Inhibit Adenosine Transport at Relevant Concentrations: A Randomized Cross-Over Study in Healthy Subjects In Vivo

    PubMed Central

    Rongen, G. A.; van den Broek, P. H. H.; Bilos, A.; Donders, A. R. T.; Gomes, M. E.; Riksen, N. P.

    2015-01-01

    Background and Purpose In patients with myocardial infarction, ticagrelor reduces cardiovascular and sepsis-related mortality, and can cause dyspnea. It is suggested that this is caused by adenosine receptor stimulation, because in preclinical studies, ticagrelor blocks the nucleoside transporter and increases cellular ATP release. We now investigated the effects of ticagrelor on the adenosine system in humans in vivo. Experimental Approach In a double-blinded, placebo-controlled cross-over trial in 14 healthy subjects, we have tested whether ticagrelor (180 mg) affects adenosine- and dipyridamole-induced forearm vasodilation, as surrogates of nucleoside uptake inhibition and adenosine formation, respectively. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was measured. Primary endpoint was adenosine-induced vasodilation. Key Results Ticagrelor did not affect adenosine- or dipyridamole-induced forearm vasodilation. Also, ex vivo uptake of adenosine and uridine in isolated red blood cells was not affected by ticagrelor. In vitro, ticagrelor dose-dependently inhibited nucleoside uptake, but only at supra-physiological concentrations. Conclusion and Implications In conclusion, at relevant plasma concentration, ticagrelor does not affect adenosine transport, nor adenosine formation in healthy subjects. Therefore, it is unlikely that this mechanism is a relevant pleiotropic effect of ticagrelor. Trial Registration ClinicalTrials.gov NCT01996735 PMID:26509673

  6. Observational constraints on atmospheric and oceanic cross-equatorial heat transports: revisiting the precipitation asymmetry problem in climate models

    NASA Astrophysics Data System (ADS)

    Loeb, Norman G.; Wang, Hailan; Cheng, Anning; Kato, Seiji; Fasullo, John T.; Xu, Kuan-Man; Allan, Richard P.

    2016-05-01

    Satellite based top-of-atmosphere (TOA) and surface radiation budget observations are combined with mass corrected vertically integrated atmospheric energy divergence and tendency from reanalysis to infer the regional distribution of the TOA, atmospheric and surface energy budget terms over the globe. Hemispheric contrasts in the energy budget terms are used to determine the radiative and combined sensible and latent heat contributions to the cross-equatorial heat transports in the atmosphere (AHTEQ) and ocean (OHTEQ). The contrast in net atmospheric radiation implies an AHTEQ from the northern hemisphere (NH) to the southern hemisphere (SH) (0.75 PW), while the hemispheric difference in sensible and latent heat implies an AHTEQ in the opposite direction (0.51 PW), resulting in a net NH to SH AHTEQ (0.24 PW). At the surface, the hemispheric contrast in the radiative component (0.95 PW) dominates, implying a 0.44 PW SH to NH OHTEQ. Coupled model intercomparison project phase 5 (CMIP5) models with excessive net downward surface radiation and surface-to-atmosphere sensible and latent heat transport in the SH relative to the NH exhibit anomalous northward AHTEQ and overestimate SH tropical precipitation. The hemispheric bias in net surface radiative flux is due to too much longwave surface radiative cooling in the NH tropics in both clear and all-sky conditions and excessive shortwave surface radiation in the SH subtropics and extratropics due to an underestimation in reflection by clouds.

  7. Brain-expressed 3′UTR extensions strengthen miRNA cross-talk between ion channel/transporter encoding mRNAs

    PubMed Central

    Wehrspaun, Claudia C.; Ponting, Chris P.; Marques, Ana C.

    2014-01-01

    Why protein-coding genes express transcripts with longer 3′untranslated regions (3′UTRs) in the brain rather than in other tissues remains poorly understood. Given the established role of 3′UTRs in post-transcriptional regulation of transcript abundance and their recently highlighted contributions to miRNA-mediated cross-talk between mRNAs, we hypothesized that 3′UTR lengthening enhances coordinated expression between functionally-related genes in the brain. To test this hypothesis, we annotated 3′UTRs of human brain-expressed genes and found that transcripts encoding ion channels or transporters are specifically enriched among those genes expressing their longest 3′UTR extension in this tissue. These 3′UTR extensions have high density of response elements predicted for those miRNAs that are specifically expressed in the human frontal cortex (FC). Importantly, these miRNA response elements are more frequently shared among ion channel/transporter-encoding mRNAs than expected by chance. This indicates that miRNA-mediated cross-talk accounts, at least in part, for the observed coordinated expression of ion channel/transporter genes in the adult human brain. We conclude that extension of these genes' 3′UTRs enhances the miRNA-mediated cross-talk among their transcripts which post-transcriptionally regulates their mRNAs' relative levels. PMID:24616735

  8. Relating climate and sand transport to incipient dune development.

    NASA Astrophysics Data System (ADS)

    van Puijenbroek, Marinka; Limpens, Juul; Gleichman, Maurits; Berendse, Frank

    2014-05-01

    Sea levels are continuously rising, increasing the risk of flooding and coastal erosion in low-elevation countries, such as the Netherlands. Coastal dunes are seen as a flexible and natural type of coastal defence, that is able to keep pace with rising water levels. Until now most research has focussed on dynamics and maintenance of established dunes, largely ignoring two critical transitions in early dune development: the transition from bare beach to vegetated incipient dune and that from incipient dune to established foredune. This knowledge is essential to enable more accurate prediction and even stimulation of new dune formation through sand nourishment. We explored the relative contributions of climate and sand transport to incipient dune development combining a 30 year time-series of aerial photographs (1979 - 2010) of the natural Wadden Island coast with high-resolution monitoring data of sand volume changes and climatic parameters. We selected 20 strips of 2.5 km in length along the coast of the Wadden Islands, with a 2 km buffer between them to avoid autocorrelation. For each of these strips of coast we assessed the changes in presence and area of incipient dunes over periods of 5-6 years. Change in fore dune volume and beach width were derived from high resolution beach elevation data. Seawater level and climate data were derived from a nearby meteorological station Preliminary analysis of the first half of the dataset showed that incipient dune area was positively related to beach width, but negatively to storm intensity. In our poster we will present the whole dataset and discuss the implications of our results for future dune development and anthropogenic sand nourishment schemes.

  9. 31 CFR 575.208 - Prohibited transportation-related transactions involving Iraq.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transactions involving Iraq. 575.208 Section 575.208 Money and Finance: Treasury Regulations Relating to Money... REGULATIONS Prohibitions § 575.208 Prohibited transportation-related transactions involving Iraq. Except as... transportation to or from Iraq; (b) The provision of transportation to or from the United States by any...

  10. Sediment transport patterns in the San Francisco Bay Coastal System from cross-validation of bedform asymmetry and modeled residual flux

    USGS Publications Warehouse

    Barnard, Patrick L.; Erikson, Li H.; Elias, Edwin P.L.; Dartnell, Peter

    2013-01-01

    The morphology of ~ 45,000 bedforms from 13 multibeam bathymetry surveys was used as a proxy for identifying net bedload sediment transport directions and pathways throughout the San Francisco Bay estuary and adjacent outer coast. The spatially-averaged shape asymmetry of the bedforms reveals distinct pathways of ebb and flood transport. Additionally, the region-wide, ebb-oriented asymmetry of 5% suggests net seaward-directed transport within the estuarine-coastal system, with significant seaward asymmetry at the mouth of San Francisco Bay (11%), through the northern reaches of the Bay (7-8%), and among the largest bedforms (21% for λ > 50 m). This general indication for the net transport of sand to the open coast strongly suggests that anthropogenic removal of sediment from the estuary, particularly along clearly defined seaward transport pathways, will limit the supply of sand to chronically eroding, open-coast beaches. The bedform asymmetry measurements significantly agree (up to ~ 76%) with modeled annual residual transport directions derived from a hydrodynamically-calibrated numerical model, and the orientation of adjacent, flow-sculpted seafloor features such as mega-flute structures, providing a comprehensive validation of the technique. The methods described in this paper to determine well-defined, cross-validated sediment transport pathways can be applied to estuarine-coastal systems globally where bedforms are present. The results can inform and improve regional sediment management practices to more efficiently utilize often limited sediment resources and mitigate current and future sediment supply-related impacts.

  11. Sediment transport patterns in the San Francisco Bay Coastal System from cross-validation of bedform asymmetry and modeled residual flux

    USGS Publications Warehouse

    Barnard, Patrick L.; Erikson, Li H.; Elias, Edwin P.L.; Dartnell, Peter

    2013-01-01

    The morphology of ~ 45,000 bedforms from 13 multibeam bathymetry surveys was used as a proxy for identifying net bedload sediment transport directions and pathways throughout the San Francisco Bay estuary and adjacent outer coast. The spatially-averaged shape asymmetry of the bedforms reveals distinct pathways of ebb and flood transport. Additionally, the region-wide, ebb-oriented asymmetry of 5% suggests net seaward-directed transport within the estuarine-coastal system, with significant seaward asymmetry at the mouth of San Francisco Bay (11%), through the northern reaches of the Bay (7–8%), and among the largest bedforms (21% for λ > 50 m). This general indication for the net transport of sand to the open coast strongly suggests that anthropogenic removal of sediment from the estuary, particularly along clearly defined seaward transport pathways, will limit the supply of sand to chronically eroding, open-coast beaches. The bedform asymmetry measurements significantly agree (up to ~ 76%) with modeled annual residual transport directions derived from a hydrodynamically-calibrated numerical model, and the orientation of adjacent, flow-sculpted seafloor features such as mega-flute structures, providing a comprehensive validation of the technique. The methods described in this paper to determine well-defined, cross-validated sediment transport pathways can be applied to estuarine-coastal systems globally where bedforms are present. The results can inform and improve regional sediment management practices to more efficiently utilize often limited sediment resources and mitigate current and future sediment supply-related impacts.

  12. Driver's behavioural changes with new intelligent transport system interventions at railway level crossings--A driving simulator study.

    PubMed

    Larue, Grégoire S; Kim, Inhi; Rakotonirainy, Andry; Haworth, Narelle L; Ferreira, Luis

    2015-08-01

    Improving safety at railway level crossings is an important issue for the Australian transport system. Governments, the rail industry and road organisations have tried a variety of countermeasures for many years to improve railway level crossing safety. New types of intelligent transport system (ITS) interventions are now emerging due to the availability and the affordability of technology. These interventions target both actively and passively protected railway level crossings and attempt to address drivers' errors at railway crossings, which are mainly a failure to detect the crossing or the train and misjudgement of the train approach speed and distance. This study aims to assess the effectiveness of three emerging ITS that the rail industry considers implementing in Australia: a visual in-vehicle ITS, an audio in-vehicle ITS, as well as an on-road flashing beacons intervention. The evaluation was conducted on an advanced driving simulator with 20 participants per trialled technology, each participant driving once without any technology and once with one of the ITS interventions. Every participant drove through a range of active and passive crossings with and without trains approaching. Their speed approach of the crossing, head movements and stopping compliance were measured. Results showed that driver behaviour was changed with the three ITS interventions at passive crossings, while limited effects were found at active crossings, even with reduced visibility. The on-road intervention trialled was unsuccessful in improving driver behaviour; the audio and visual ITS improved driver behaviour when a train was approaching. A trend toward worsening driver behaviour with the visual ITS was observed when no trains were approaching. This trend was not observed for the audio ITS intervention, which appears to be the ITS intervention with the highest potential for improving safety at passive crossings. PMID:25956609

  13. Quantification of cross polarization with relaxation compensated reciprocity relation in NMR

    NASA Astrophysics Data System (ADS)

    Shu, Jie; Chen, Qun; Zhang, Shanmin

    2008-09-01

    The reciprocity relation in solid state NMR has been extended to include the effects of spin-lattice relaxation in the rotating frame. This method was successfully applied to the experiments of Hartmann-Hahn cross polarization, making the originally non-quantified NMR spectra quantitative. In addition, it provides detailed dynamics of cross polarization that is often obscured by spin-lattice relaxation in the rotating frame and by some other effects.

  14. Reading Retardation and Cross-Laterality in Relation to Short-Term Information Processing Tasks

    ERIC Educational Resources Information Center

    Wheeler, T. J.; And Others

    1977-01-01

    Predicts that ill-established cerebral dominance, as indicated by the problems of cross-laterality, would be related both to a limitation in information processing "irrespective of the type of information" (probably manifesting itself even with relatively small amounts of information) and significantly to reading retardation. (Author/RK)

  15. Sodium transport is modulated by p38 kinase-dependent cross-talk between ENaC and Na,K-ATPase in collecting duct principal cells.

    PubMed

    Wang, Yu-Bao; Leroy, Valérie; Maunsbach, Arvid B; Doucet, Alain; Hasler, Udo; Dizin, Eva; Ernandez, Thomas; de Seigneux, Sophie; Martin, Pierre-Yves; Féraille, Eric

    2014-02-01

    In relation to dietary Na(+) intake and aldosterone levels, collecting duct principal cells are exposed to large variations in Na(+) transport. In these cells, Na(+) crosses the apical membrane via epithelial Na(+) channels (ENaC) and is extruded into the interstitium by Na,K-ATPase. The activity of ENaC and Na,K-ATPase must be highly coordinated to accommodate variations in Na(+) transport and minimize fluctuations in intracellular Na(+) concentration. We hypothesized that, independent of hormonal stimulus, cross-talk between ENaC and Na,K-ATPase coordinates Na(+) transport across apical and basolateral membranes. By varying Na(+) intake in aldosterone-clamped rats and overexpressing γ-ENaC or modulating apical Na(+) availability in cultured mouse collecting duct cells, enhanced apical Na(+) entry invariably led to increased basolateral Na,K-ATPase expression and activity. In cultured collecting duct cells, enhanced apical Na(+) entry increased the basolateral cell surface expression of Na,K-ATPase by inhibiting p38 kinase-mediated endocytosis of Na,K-ATPase. Our results reveal a new role for p38 kinase in mediating cross-talk between apical Na(+) entry via ENaC and its basolateral exit via Na,K-ATPase, which may allow principal cells to maintain intracellular Na(+) concentrations within narrow limits. PMID:24179170

  16. Sodium Transport Is Modulated by p38 Kinase–Dependent Cross-Talk between ENaC and Na,K-ATPase in Collecting Duct Principal Cells

    PubMed Central

    Wang, Yu-Bao; Leroy, Valérie; Maunsbach, Arvid B.; Doucet, Alain; Hasler, Udo; Dizin, Eva; Ernandez, Thomas; de Seigneux, Sophie; Martin, Pierre-Yves

    2014-01-01

    In relation to dietary Na+ intake and aldosterone levels, collecting duct principal cells are exposed to large variations in Na+ transport. In these cells, Na+ crosses the apical membrane via epithelial Na+ channels (ENaC) and is extruded into the interstitium by Na,K-ATPase. The activity of ENaC and Na,K-ATPase must be highly coordinated to accommodate variations in Na+ transport and minimize fluctuations in intracellular Na+ concentration. We hypothesized that, independent of hormonal stimulus, cross-talk between ENaC and Na,K-ATPase coordinates Na+ transport across apical and basolateral membranes. By varying Na+ intake in aldosterone-clamped rats and overexpressing γ-ENaC or modulating apical Na+ availability in cultured mouse collecting duct cells, enhanced apical Na+ entry invariably led to increased basolateral Na,K-ATPase expression and activity. In cultured collecting duct cells, enhanced apical Na+ entry increased the basolateral cell surface expression of Na,K-ATPase by inhibiting p38 kinase-mediated endocytosis of Na,K-ATPase. Our results reveal a new role for p38 kinase in mediating cross-talk between apical Na+ entry via ENaC and its basolateral exit via Na,K-ATPase, which may allow principal cells to maintain intracellular Na+ concentrations within narrow limits. PMID:24179170

  17. Cross-shelf transport into nearshore waters due to shoaling internal tides in San Pedro Bay, CA

    USGS Publications Warehouse

    Noble, M.; Jones, B.; Hamilton, P.; Xu, Jie; Robertson, G.; Rosenfeld, L.; Largier, J.

    2009-01-01

    In the summer of 2001, a coastal ocean measurement program in the southeastern portion of San Pedro Bay, CA, was designed and carried out. One aim of the program was to determine the strength and effectiveness of local cross-shelf transport processes. A particular objective was to assess the ability of semidiurnal internal tidal currents to move suspended material a net distance across the shelf. Hence, a dense array of moorings was deployed across the shelf to monitor the transport patterns associated with fluctuations in currents, temperature and salinity. An associated hydrographic program periodically monitored synoptic changes in the spatial patterns of temperature, salinity, nutrients and bacteria. This set of measurements show that a series of energetic internal tides can, but do not always, transport subthermocline water, dissolved and suspended material from the middle of the shelf into the surfzone. Effective cross-shelf transport occurs only when (1) internal tides at the shelf break are strong and (2) subtidal currents flow strongly downcoast. The subtidal downcoast flow causes isotherms to tilt upward toward the coast, which allows energetic, nonlinear internal tidal currents to carry subthermocline waters into the surfzone. During these events, which may last for several days, the transported water remains in the surfzone until the internal tidal current pulses and/or the downcoast subtidal currents disappear. This nonlinear internal tide cross-shelf transport process was capable of carrying water and the associated suspended or dissolved material from the mid-shelf into the surfzone, but there were no observation of transport from the shelf break into the surfzone. Dissolved nutrients and suspended particulates (such as phytoplankton) transported from the mid-shelf into the nearshore region by nonlinear internal tides may contribute to nearshore algal blooms, including harmful algal blooms that occur off local beaches.

  18. High-field electron transport in GaN under crossed electric and magnetic fields

    NASA Astrophysics Data System (ADS)

    Kochelap, V. A.; Korotyeyev, V. V.; Syngayivska, G. I.; Varani, L.

    2015-10-01

    High-field electron transport studied in crossed electric and magnetic fields in bulk GaN with doping of 1016 cm-3, compensation around 90% at the low lattice temperature (30 K). It was found the range of the magnetic and electric fields where the non-equilibrium electron distribution function has a complicated topological structure in the momentum space with a tendency to the formation of the inversion population. Field dependences of dissipative and Hall components of the drift velocity were calculated for the samples with short- and open- circuited Hall contacts in wide ranges of applied electric (0 — 20 kV/cm) and magnetic (1 — 10 T) fields. For former sample, field dependences of dissipative and Hall components of the drift velocity have a non-monotonic behavior. The dissipative component has the inflection point which corresponds to the maximum point of the Hall component. For latter sample, the drift velocity demonstrate a usual sub-linear growth without any critical points. We found that GaN samples with controlled resistance of the Hall circuit can be utilized as a electronic high-power switch.

  19. Matrix association effects on hydrodynamic sorting and degradation of terrestrial organic matter during cross-shelf transport in the Laptev and East Siberian shelf seas

    NASA Astrophysics Data System (ADS)

    Tesi, Tommaso; Semiletov, Igor; Dudarev, Oleg; Andersson, August; Gustafsson, Örjan

    2016-03-01

    This study seeks an improved understanding of how matrix association affects the redistribution and degradation of terrigenous organic carbon (TerrOC) during cross-shelf transport in the Siberian margin. Sediments were collected at increasing distance from two river outlets (Lena and Kolyma Rivers) and one coastal region affected by erosion. Samples were fractionated according to density, size, and settling velocity. The chemical composition in each fraction was characterized using elemental analyses and terrigenous biomarkers. In addition, a dual-carbon-isotope mixing model (δ13C and Δ14C) was used to quantify the relative TerrOC contributions from active layer (Topsoil) and Pleistocene Ice Complex Deposits (ICD). Results indicate that physical properties of particles exert first-order control on the redistribution of different TerrOC pools. Because of its coarse nature, plant debris is hydraulically retained in the coastal region. With increasing distance from the coast, the OC is mainly associated with fine/ultrafine mineral particles. Furthermore, biomarkers indicate that the selective transport of fine-grained sediment results in mobilizing high-molecular weight (HMW) lipid-rich, diagenetically altered TerrOC while lignin-rich, less degraded TerrOC is retained near the coast. The loading (µg/m2) of lignin and HMW wax lipids on the fine/ultrafine fraction drastically decreases with increasing distance from the coast (98% and 90%, respectively), which indicates extensive degradation during cross-shelf transport. Topsoil-C degrades more readily (90 ± 3.5%) compared to the ICD-C (60 ± 11%) during transport. Altogether, our results indicate that TerrOC is highly reactive and its accelerated remobilization from thawing permafrost followed by cross-shelf transport will likely represent a positive feedback to climate warming.

  20. Polar Transport Related to Mobilization of Plant Constituents

    PubMed Central

    Zaerr, J. B.; Mitchell, J. W.

    1967-01-01

    Indole-3-acetic acid (IAA), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), sucrose, and mannitol, were tested for polar transport through 5-mm hypocotyl segments of bean (Phaseolus vulgaris var. Pinto) seedlings. All 4 compounds were transported in a polar direction. Autoradiographs of segments through which 14C-labeled compounds were transported indicated areas of 14C concentration near the morphological base of segments. There was a direct correlation of IAA transport with the ability to initiate roots as well as with the degree of 14C accumulation in the morphological base of segments. Unlabeled IAA in lanolin applied to segments appeared to reduce transport of IAA-14C through those segments when measured by the accumulation of 14C in a receiver-block of agar, caused an increase in 14C accumulation in the region to which the unlabeled IAA was applied, and also caused a decrease in accumulation of 14C at the morphological base of upright segments. Histological studies showed that IAA accelerated cell division and the formation of root primordia particularly at the basal ends, and that these responses sometimes occurred at the expense of cell proliferation at the apical ends of segments. The data presented support the hypothesis that polar movement of IAA, and other endogenous and exogenous substances, in isolated stem segments was controlled by mobilization and utilization of plant constituents at the growth centers. Images PMID:16656584

  1. Policies related to active transport to and from school: a multisite case study.

    PubMed

    Eyler, Amy A; Brownson, Ross C; Doescher, Mark P; Evenson, Kelly R; Fesperman, Carrie E; Litt, Jill S; Pluto, Delores; Steinman, Lesley E; Terpstra, Jennifer L; Troped, Philip J; Schmid, Thomas L

    2008-12-01

    Active transportation to and from school (ATS) is a viable strategy to help increase physical activity among youth. ATS can be challenging because initiatives require transdisciplinary collaboration, are influenced by the built environment and are affected by numerous policies. The purpose of this study is to identify policies and factors that influence ATS initiatives. Nine elementary schools in seven states participated in this case study. Sixty-nine stakeholders were interviewed. The interviews were transcribed, coded and analyzed using a master thematic codebook. This study identified two distinct aspects of policies: 'influential factors' which are factors that might impact policies related to ATS and 'policy actions' which are policies reported by people involved in ATS initiatives that directly affected their success. Influential factors included sidewalks, crosswalks/crossing guards, funding, personal safety concerns, advocacy group involvement and others. Policy actions included policies on school speed zone, drop-off, no-transport zones, school siting, school start/dismissal time and school choice. Despite the diversity of the schools studied, similarities included influence of built environment, safety concerns, funding and transdisciplinary collaboration. Stakeholders need to work together to stimulate action and ensure successful initiatives. Influential factors appear to be important to this process. PMID:17956883

  2. Effect of training intensity on muscle lactate transporters and lactate threshold of cross-country skiers.

    PubMed

    Evertsen, F; Medbø, J I; Bonen, A

    2001-10-01

    The training intensity may affect the monocarboxylate transporters MCT1 and MCT4 in skeletal muscle. Therefore, 20 elite cross-country skiers (11 men and nine women) trained hard for 5 months at either moderate (MIG, 60-70% of VO2max) or high intensity (HIG, 80-90%). The lactate threshold, several performance parameters, and the blood lactate concentration (cLa) after exhausting treadmill running were also determined. Muscle biopsies taken from the vastus lateralis muscle before and after the training period were analysed for the two MCTs and for muscle fibre types and six enzymes. The concentration of MCT1 did not change for HIG (P=0.3) but fell for MIG (-12 +/- 3%, P=0.01); the training response differed between the two groups (P=0.05). The concentration of MCT4 did not change during the training period (P > 0.10). The concentration of the two MCTs did not differ between the two sexes (P=0.9). The running speed at the lactate threshold rose for HIG (+3.2 +/- 0.9%, P=0.003), while no change was seen for MIG (P=0.54); the training response differed between the two groups (P=0.04). The cLa after long-lasting exhausting treadmill running correlated with the concentration of MCT1 (rs=0.69, P=0.002), but not with that of MCT4 (rs=0.2, P=0.2). There were no other significant correlations between the concentrations of the two MCTs and the performance parameters, muscle fibre types, or enzymes (r < or = 0.36, P > 0.10). Thus, the training response differed between MIG and HIG both in terms of performance and of the effect on MCT1. Training at high intensity may be more effective for cross-country skiers. Finally, MCT1 may be important for releasing lactate to the blood during long-lasting exercise. PMID:11683677

  3. Sudden Clearing of Estuarine Waters upon Crossing the Threshold from Transport to Supply Regulation of Sediment Transport as an Erodible Sediment Pool is Depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, D.H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991-1998 to 1999-2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing. ?? 2011 Coastal and Estuarine Research Federation (outside the USA).

  4. Crossing Boundaries in Doctoral Education: Relational Learning, Cohort Communities, and Dissertation Committees

    ERIC Educational Resources Information Center

    Holloway, Elizabeth L.; Alexandre, Laurien

    2012-01-01

    This chapter explores relational boundary crossing in doctoral education as a way to improve student learning and faculty satisfaction. A brief introduction sets the stage by articulating a recognized set of challenges for student learning in the current context of U.S. doctoral education. The chapter then introduces elements of an innovative…

  5. Cross-Lagged Relations between Task-Avoidant Behavior and Literacy Skills in Chinese

    ERIC Educational Resources Information Center

    Liao, Chen-Huei; Georgiou, George K.; Zhang, Xiao; Nurmi, Jari-Erik

    2013-01-01

    We examined the cross-lagged relations between children's task-avoidant behavior and their performance in reading and spelling in Chinese. Eighty Grade 2 and 103 Grade 4 Mandarin-speaking Taiwanese children were assessed on measures of nonverbal IQ, task value, reading accuracy, fluency, and spelling. A year later, the children were reassessed on…

  6. A Cross-Cultural Comparison of Adolescents' Experience Related to Cyberbullying

    ERIC Educational Resources Information Center

    Li, Qing

    2008-01-01

    Background and purpose: This study explores the issues of cyberbullying from a cross-cultural perspective. The focus is on the examination of the extent of a sample of Canadian and Chinese adolescents' experiences and possible culture differences related to bullying and cyberbullying. Sample: Two sets of data were collected in Canada and China. In…

  7. Fission cross sections of some thorium, uranium, neptunium and plutonium isotopes relative to /sup 235/U

    SciTech Connect

    Meadows, J W

    1983-10-01

    Earlier results from the measurements, at this Laboratory, of the fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu, /sup 240/Pu, and /sup 242/Pu relative to /sup 235/U are reviewed with revisions to include changes in data processing procedures, alpha half lives and thermal fission cross sections. Some new data have also been included. The current experimental methods and procedures and the sample assay methods are described in detail and the sources of error are presented in a systematic manner. 38 references.

  8. 44 CFR 402.6 - Relation to Transportation Order T-2.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Relation to Transportation... OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.6 Relation to... Positive List of the Office of International Trade, arms and ammunition, and commodities controlled...

  9. 44 CFR 402.6 - Relation to Transportation Order T-2.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Relation to Transportation... OF TRANSPORTATION SHIPMENTS ON AMERICAN FLAG SHIPS AND AIRCRAFT (T-1, INT. 1) § 402.6 Relation to... Positive List of the Office of International Trade, arms and ammunition, and commodities controlled...

  10. Thermodynamic and transport properties of cryogenic propellants and related fluids

    NASA Technical Reports Server (NTRS)

    Johnson, V. J.

    1973-01-01

    Significant advances have been made in recent years in the quality and range of thermophysical data for the cryogenic propellants, pressurants, and inertants. A review of recently completed and current data compilation projects for helium, hydrogen, argon, nitrogen, oxygen, fluorine, and methane is given together with recommended references for thermodynamic and transport property data tables for these fluids. Modern techniques in the plotting of thermodynamic charts from tabular data (or from functions such as the equation of state) have greatly improved their precision and value. A list of such charts is included.

  11. Radon transport in soil and its relation to indoor radioactivity.

    PubMed

    Wilkening, M

    1985-10-01

    The transport of radon from soil to the indoor living space involves diffusion and viscous flow in the soil coupled with transfer to the building interior of radon-rich air which accumulates in cavities and channels below and around the foundations of buildings. Radon concentrations in soil pores at depth are dependent upon the radium content of the soil, emanating power for radium, and soil moisture content. Atmospheric pressure fluctuation, thermal gradients in fractured rocks, and air instabilities due to temperature differences allow air of high radon content to reach living space in dwellings in addition to that which comes directly from building materials and other sources. PMID:4081718

  12. Serological Cross-Reactivity between Merkel Cell Polyomavirus and Two Closely Related Chimpanzee Polyomaviruses

    PubMed Central

    Nicol, Jérôme T. J.; Liais, Etienne; Potier, Romain; Mazzoni, Elisa; Tognon, Mauro; Coursaget, Pierre; Touzé, Antoine

    2014-01-01

    Phylogenetic analyses based on the major capsid protein sequence indicate that Merkel cell polyomavirus (MCPyV) and chimpanzee polyomaviruses (PtvPyV1, PtvPyV2), and similarly Trichodysplasia spinulosa-associated polyomavirus (TSPyV) and the orangutan polyomavirus (OraPyV1) are closely related. The existence of cross-reactivity between these polyomaviruses was therefore investigated. The findings indicated serological identity between the two chimpanzee polyomaviruses investigated and a high level of cross-reactivity with Merkel cell polyomavirus. In contrast, cross-reactivity was not observed between TSPyV and OraPyV1. Furthermore, specific antibodies to chimpanzee polyomaviruses were detected in chimpanzee sera by pre-incubation of sera with the different antigens, but not in human sera. PMID:24816721

  13. Cross-Fostering Differentially Affects ADHD-Related Behaviors in Spontaneously Hypertensive Rats

    PubMed Central

    Gauthier, Angela C.; DeAngeli, Nicole E.; Bucci, David J.

    2014-01-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain. PMID:25647439

  14. Cross-fostering differentially affects ADHD-related behaviors in spontaneously hypertensive rats.

    PubMed

    Gauthier, Angela C; DeAngeli, Nicole E; Bucci, David J

    2015-03-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain. PMID:25647439

  15. COHeRE: Cross-Ontology Hierarchical Relation Examination for Ontology Quality Assurance

    PubMed Central

    Cui, Licong

    2015-01-01

    Biomedical ontologies play a vital role in healthcare information management, data integration, and decision support. Ontology quality assurance (OQA) is an indispensable part of the ontology engineering cycle. Most existing OQA methods are based on the knowledge provided within the targeted ontology. This paper proposes a novel cross-ontology analysis method, Cross-Ontology Hierarchical Relation Examination (COHeRE), to detect inconsistencies and possible errors in hierarchical relations across multiple ontologies. COHeRE leverages the Unified Medical Language System (UMLS) knowledge source and the MapReduce cloud computing technique for systematic, large-scale ontology quality assurance work. COHeRE consists of three main steps with the UMLS concepts and relations as the input. First, the relations claimed in source vocabularies are filtered and aggregated for each pair of concepts. Second, inconsistent relations are detected if a concept pair is related by different types of relations in different source vocabularies. Finally, the uncovered inconsistent relations are voted according to their number of occurrences across different source vocabularies. The voting result together with the inconsistent relations serve as the output of COHeRE for possible ontological change. The highest votes provide initial suggestion on how such inconsistencies might be fixed. In UMLS, 138,987 concept pairs were found to have inconsistent relationships across multiple source vocabularies. 40 inconsistent concept pairs involving hierarchical relationships were randomly selected and manually reviewed by a human expert. 95.8% of the inconsistent relations involved in these concept pairs indeed exist in their source vocabularies rather than being introduced by mistake in the UMLS integration process. 73.7% of the concept pairs with suggested relationship were agreed by the human expert. The effectiveness of COHeRE indicates that UMLS provides a promising environment to enhance

  16. COHeRE: Cross-Ontology Hierarchical Relation Examination for Ontology Quality Assurance.

    PubMed

    Cui, Licong

    2015-01-01

    Biomedical ontologies play a vital role in healthcare information management, data integration, and decision support. Ontology quality assurance (OQA) is an indispensable part of the ontology engineering cycle. Most existing OQA methods are based on the knowledge provided within the targeted ontology. This paper proposes a novel cross-ontology analysis method, Cross-Ontology Hierarchical Relation Examination (COHeRE), to detect inconsistencies and possible errors in hierarchical relations across multiple ontologies. COHeRE leverages the Unified Medical Language System (UMLS) knowledge source and the MapReduce cloud computing technique for systematic, large-scale ontology quality assurance work. COHeRE consists of three main steps with the UMLS concepts and relations as the input. First, the relations claimed in source vocabularies are filtered and aggregated for each pair of concepts. Second, inconsistent relations are detected if a concept pair is related by different types of relations in different source vocabularies. Finally, the uncovered inconsistent relations are voted according to their number of occurrences across different source vocabularies. The voting result together with the inconsistent relations serve as the output of COHeRE for possible ontological change. The highest votes provide initial suggestion on how such inconsistencies might be fixed. In UMLS, 138,987 concept pairs were found to have inconsistent relationships across multiple source vocabularies. 40 inconsistent concept pairs involving hierarchical relationships were randomly selected and manually reviewed by a human expert. 95.8% of the inconsistent relations involved in these concept pairs indeed exist in their source vocabularies rather than being introduced by mistake in the UMLS integration process. 73.7% of the concept pairs with suggested relationship were agreed by the human expert. The effectiveness of COHeRE indicates that UMLS provides a promising environment to enhance

  17. The taste-visual cross-modal Stroop effect: An event-related brain potential study.

    PubMed

    Xiao, X; Dupuis-Roy, N; Yang, X L; Qiu, J F; Zhang, Q L

    2014-03-28

    Event-related potentials (ERPs) were recorded to explore, for the first time, the electrophysiological correlates of the taste-visual cross-modal Stroop effect. Eighteen healthy participants were presented with a taste stimulus and a food image, and asked to categorize the image as "sweet" or "sour" by pressing the relevant button as quickly as possible. Accurate categorization of the image was faster when it was presented with a congruent taste stimulus (e.g., sour taste/image of lemon) than with an incongruent one (e.g., sour taste/image of ice cream). ERP analyses revealed a negative difference component (ND430-620) between 430 and 620ms in the taste-visual cross-modal Stroop interference. Dipole source analysis of the difference wave (incongruent minus congruent) indicated that two generators localized in the prefrontal cortex and the parahippocampal gyrus contributed to this taste-visual cross-modal Stroop effect. This result suggests that the prefrontal cortex is associated with the process of conflict control in the taste-visual cross-modal Stroop effect. Also, we speculate that the parahippocampal gyrus is associated with the process of discordant information in the taste-visual cross-modal Stroop effect. PMID:24418613

  18. Characterization of cross-linked cellulosic ion-exchange adsorbents: 2. Protein sorption and transport.

    PubMed

    Angelo, James M; Cvetkovic, Aleksandar; Gantier, Rene; Lenhoff, Abraham M

    2016-03-18

    Adsorption behavior in the HyperCel family of cellulosic ion-exchange materials (Pall Corporation) was characterized using methods to assess, quantitatively and qualitatively, the dynamics of protein uptake as well as static adsorption as a function of ionic strength and protein concentration using several model proteins. The three exchangers studied all presented relatively high adsorptive capacities under low ionic strength conditions, comparable to commercially available resins containing polymer functionalization aimed at increasing that particular characteristic. The strong cation- and anion-exchange moieties showed higher sensitivity to increasing salt concentrations, but protein affinity on the salt-tolerant STAR AX HyperCel exchanger remained strong at ionic strengths normally used in downstream processing to elute material fully during ion-exchange chromatography. Very high uptake rates were observed in both batch kinetics experiments and time-series confocal laser scanning microscopy, suggesting low intraparticle transport resistances relative to external film resistance, even at higher bulk protein concentrations where the opposite is typically observed. Electron microscopy imaging of protein adsorbed phases provided additional insight into particle structure that could not be resolved in previous work on the bare resins. PMID:26905881

  19. Walking for transportation in Hong Kong Chinese urban elders: a cross-sectional study on what destinations matter and when

    PubMed Central

    2013-01-01

    Background Walking for transport can contribute to the accrual of health-enhancing levels of physical activity in elders. Identifying destinations and environmental conditions that facilitate this type of walking has public health significance. However, most findings are limited to Western, low-density locations, while a larger proportion of the global population resides in ultra-dense Asian metropolises. We investigated relationships of within-neighborhood objectively-measured destination categories and environmental attributes with walking for transport in 484 elders from an ultra-dense metropolis (Hong Kong). Methods We estimated relationships of diversity (number of different types) and prevalence of within-neighborhood destination categories (environmental audits of 400 m buffers surrounding residential addresses) with transport-related walking (interviewer–administered questionnaire) in 484 Chinese-speaking elders able to walk unassisted and living in 32 neighborhoods stratified by socio-economic status and transport-related walkability. We examined the moderating effects of safety and pedestrian infrastructure-related neighborhood attributes on destination-walking associations. Results Participants reported on average 569 and 254 min/week of overall and within-neighborhood walking for transport, respectively. The prevalence of public transit points and diversity of recreational destinations were positively related to overall walking for transport. The presence of a health clinic/service and place of worship, higher diversity in recreational destinations, and greater prevalence of non-food retails and services, food/grocery stores, and restaurants in the neighborhood were predictive of more within-neighborhood walking for transport. Neighborhood safety-related aspects moderated the relationship of overall walking for transport with the prevalence of public transit points, this being positive only in safe locations. Similar moderating effects of safety-related

  20. Polar auxin transport in relation to long-distance transport of nutrients in the Charales.

    PubMed

    Raven, John A

    2013-01-01

    This paper examines the significance of the recent demonstration of polar auxin transport (PAT) in the green macroalga Chara (Charophyceae: Charales) and, especially, options for explaining some features of PAT in the Charales. The occurrence of PAT in the Charales shows that PAT originated in the algal ancestors of the embryophytes (liverworts, mosses, hornworts, and vascular plants), although it is not yet known if PAT occurs elsewhere in the Charophyceae or in other algae. While in the embryophytes PAT occurs in parenchymatously constructed structures which commonly also have xylem and phloem (or their bryophyte analogues) as long-distance transport processes in parallel to PAT, in Chara corallina PAT shares the pathway for long-distance transport of nutrients though the parenchymatously constructed nodal complexes and the single giant cells of the internode. The speed of auxin movement of PAT is much more rapid than that attributable to diffusion and of the same order as the rate of cytoplasmic streaming in the giant internodal cells, yet complete inhibition of streaming by the inhibitor cytochalasin H does not slow down auxin transport. Explanations for this phenomenon are sought in the operation of other mechanochemical motors, dynein-tubulin and kinesin-tubulin, as alternatives to the myosin-actin system which powers cytoplasmic streaming. Experiments in which microtubules are disrupted, for example by colchicine, could show if one of the tubulin-based motors is involved. If these motors are involved, some mechanism is needed to amplify the speeds known for the motors to explain the order of magnitude higher speeds seen for auxin transport. PMID:23264638

  1. Indian MST radar: A remote sensing tool for studying long- and short- term cross tropopause transports

    NASA Astrophysics Data System (ADS)

    Das, Siddarth Shankar; Ratnam, Madineni Venkat; Suneeth, K. V.

    The stratospheric air is dry and ozone rich in nature, whereas the tropospheric air is enriched in humidity with high aerosol concentration. The tropopause is the stable layer which acts as a semi-permeable membrane between these two spheres (i.e. troposphere and stratosphere) and thus hinders the exchange of the minors constituents (e.g. water vapour and ozone) between these two spheres. This complex equilibrium region is known as the upper troposphere and lower stratosphere (UTLS) region. The major mixing process befalls over the tropical region, where the maximum convective systems occur through the tropical tropopause layer (TTL). Thus, it is necessary to understand the dynamical and chemical processes that occurring at UTLS region and quantative analysis of the mass exchange is essential. Ten years of data obtained from Indian MST radar located at a Tropical station Gadanki (13.5oN, 79.2oE) is used to study the long- and short (event) term cross tropopause transport. The prime mechanisms responsible for the radar backscattering echoes are isotropic/anisotropic turbulence fluctuations in the refractive index and Fresnel reflection/scattering due to sharp gradients in the radio refractive index. The inhomogeneties in the radio refractive index are contributed by both humidity and temperature below 8 km height, whereas above it, it is only contributed by the temperature gradients. When the dry stratospheric air penetrates into the troposphere, it will take some time to mix with the humid air of troposphere. Due to two different constituents of the air, there will be strong refractive index gradient, which will be reflected as enhanced radar backscattering echoes. The dry stratospheric air will slowly mix with the humid tropospheric air by means of small scale turbulence. Using this scattering mechanism behavior, the long-term and its seasonal characteristics, and the short-term event wise (convective disturbances) stratospheric air intrusion into the troposphere

  2. Effects of seasonal and interannual variability in along-shelf and cross-shelf transport on groundfish recruitment in the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Vestfals, Cathleen D.; Ciannelli, Lorenzo; Duffy-Anderson, Janet T.; Ladd, Carol

    2014-11-01

    The Bering Sea responds rapidly to atmospheric perturbations and over the past several decades has experienced extreme variability in both its physical and biological characteristics. These changes can impact organisms that inhabit the region, particularly marine fishes, as normal current patterns to which reproductive habits are tuned can be disrupted, which, in turn, may influence recruitment and population dynamics. To understand the influence of ocean circulation on groundfish recruitment in the eastern Bering Sea, we examined transport along and across the Bering Slope derived from 23 years (1982-2004) of simulations from a Regional Ocean Modeling System (ROMS) ocean circulation model. We expected that changes in the strength and position of the Bering Slope Current (BSC) would affect recruitment in selected species (Pacific cod, walleye pollock, Greenland halibut, Pacific halibut, and arrowtooth flounder), and that circulation features along and across the shelf edge would be strongly influenced by atmospheric forcing. Variability in along-shelf transport at three transects along the path of the BSC, cross-shelf transport across the 100 and 200 m isobaths, and transport through Unimak Pass were examined. Strong seasonal and interannual variations in flow were observed, with transport typically highest during fall and winter months, coinciding with timing of spawning activity in the five species. Significant correlations were found between transport, BSC position, and groundfish recruitment. Pacific cod, in particular, benefitted from decreased along-shelf and on-shelf flow, while Pacific halibut recruitment increased in relation to increased on-shelf transport through southern canyons. The results of this study improve our understanding of variability in circulation and associated effects on groundfish recruitment in the eastern Bering Sea.

  3. The relative importance of transport phenomena in recycling isoelectric focusing.

    PubMed

    Burgaud, C; Clifton, M J; Sanchez, V

    1992-03-01

    The various transport phenomena involved in recycling isoelectric focusing are analyzed for their contributions to band spreading so as to find ways of improving the resolution of this liquid-phase protein purification method. A numerical model is proposed that takes into account diffusion, electroosmosis and electrophoretic migration as a function of pH. The electrohydrodynamic effects have so far been neglected in these calculations. The results of these calculations are compared with experimental measurements performed in different chamber geometries, with a variety of proteins and under different operating conditions, always chosen to avoid flow instabilities. This comparison shows that the resolution of this process is greatly impaired if the electroosmotic slip velocity at the wall is not suppressed. PMID:1592042

  4. Methods for measuring and transporting angular momentum in general relativity

    NASA Astrophysics Data System (ADS)

    Nichols, David; Flanagan, Eanna; Stein, Leo; Vines, Justin

    2016-03-01

    For an observer in a curved spacetime, elements of the dual space of the set of linearized Poincare transformations from the observer's tangent space to itself can naturally be interpreted as local linear and angular momenta. We give an operational procedure by which the observer can measure such local linear and angular momenta from the local spacetime geometry. These momenta can be interpreted as approximate versions of the linear and angular momenta of the spacetime about the observer's location. The measurement algorithm allows for a more accurate determination of the linear and angular momentum of stationary, asymptotically flat systems than previous proposals do. We also describe a prescription by which observers at different locations can compare values of their measured linear and angular momentum by using a specific transport equation, which refines previous proposals. These operational definitions may also prove useful for clarifying the physical interpretation of Bondi-Metzner-Sachs asymptotic charges in asymptotically flat spacetimes.

  5. Effect of end-group cross-linking on transport properties of sulfonated poly(phenylene sulfide nitrile)s for proton exchange membranes

    NASA Astrophysics Data System (ADS)

    Kang, Na Rae; Lee, So Young; Shin, Dong Won; Hwang, Doo Sung; Lee, Kang Hyuck; Cho, Doo Hee; Kim, Ji Hoon; Lee, Young Moo

    2016-03-01

    A series of end-group cross-linked membranes (Az-XESPSN) were prepared by click reaction to investigate the effects of cross-linking on the morphology and proton transport properties of proton exchange membranes. The morphological transformations resulting from thermal annealing and cross-linking were observed by means of atomic force microscopy (AFM) and transmission electron microscopy (TEM). Compared to the non-cross-linked ESPSN membranes, the Az-XESPSN membranes exhibited lower water uptake and improved mechanical and chemical stabilities. In addition, the Az-XESPSN membranes exhibited higher proton conductivities (0.018-0.028 S cm-1) compared to those of the ESPSN membranes (0.0044-0.0053 S cm-1) and Nafion 212 (0.0061 S cm-1), particularly in conditions of elevated temperature (120 °C) and low relative humidity (35%). Such enhancements can be attributed to a synergistic effect of well-defined hydrophilic ionic clusters and triazole groups that function as proton carriers under anhydrous conditions. Furthermore, the Az-XESPSN membranes exhibited significantly enhanced single cell performance and long-term stability compared to those of ESPSN membranes.

  6. Relative vs. absolute physiological measures as predictors of mountain bike cross-country race performance.

    PubMed

    Gregory, John; Johns, David P; Walls, Justin T

    2007-02-01

    The aims of this study were to document the effect terrain has on the physiological responses and work demands (power output) of riding a typical mountain bike cross-country course under race conditions. We were particularly interested in determining whether physiological measures relative to mass were better predictors of race performance than absolute measures. Eleven A-grade male cross-country mountain bike riders (VO2max 67.1 +/- 3.6 ml x kg(-1) x min(-1)) performed 2 tests: a laboratory-based maximum progressive exercise test, and a 15.5-km (six 2.58-km laps) mountain bike cross-country time trial. There were significant differences among the speed, cadence, and power output measured in each of 8 different terrain types found in the cross-country time trial course. The highest average speed was measured during the 10-15% downhill section (22.7 +/- 2.6 km x h(-1)), whereas the cadence was highest in the posttechnical flat sections (74.3 +/- 5.6 rpm) and lowest on the 15-20% downhill sections (6.4 +/- 12.1 rpm). The highest mean heart rate (HR) was obtained during the steepest (15-20% incline) section of the course (179 +/- 8 b x min(-1)), when the power output was greatest (419.8 +/- 39.7 W). However, HR remained elevated relative to power output in the downhill sections of the course. Physiological measures relative to total rider mass correlated more strongly to average course speed than did absolute measures (peak power relative to mass r = 0.93, p < 0.01, vs. peak power r = 0.64, p < 0.05; relative VO2max r = 0.80, p < 0.05, vs. VO2max r = 0.66, p < 0.05; power at anaerobic threshold relative to mass r = 0.78, p < 0.05, vs. power at anaerobic threshold r = 0.5, p < 0.05). This suggests that mountain bike cross-country training programs should focus upon improving relative physiological values rather than focusing upon maximizing absolute values to improve performance. PMID:17313256

  7. CO2-ECBM related coupled physical and mechanical transport processes

    NASA Astrophysics Data System (ADS)

    Gensterblum, Y.; Sartorius, M.; Busch, A.; Krooss, B. M.; Littke, R.

    2012-12-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a subbituminous A coal from the Surat Basin, Queensland Australia (figure). From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg-corrected permeability depends on gas type. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa, with increasing mean pore pressure at lower confining pressure an increase in permeability is observed, which is attributed to a widening of cleat aperture. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane and CO2. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals was significantly lower (by 50%) than that of dry coals, no hysteresis was observed between sorption and desorption on dry and moisture-equilibrated samples and the

  8. Cross-property relations and permeability estimation in model porous media

    SciTech Connect

    Schwartz, L.M.; Martys, N.; Bentz, D.P.; Garboczi, E.J.; Torquato, S. National Institute of Standards and Technology, Building Materials Division, Gaithersburg, Maryland 20899 Princeton Materials Institute, 70 Prospect Avenue, Princeton University, Princeton, New Jersey 08540-5211 )

    1993-12-01

    Results from a numerical study examining cross-property relations linking fluid permeability to diffusive and electrical properties are presented. Numerical solutions of the Stokes equations in three-dimensional consolidated granular packings are employed to provide a basis of comparison between different permeability estimates. Estimates based on the [Lambda] parameter (a length derived from electrical conduction) and on [ital d][sub [ital c

  9. Novel Cross-Band Relative Absorption (CoBRA) technique For Measuring Atmospheric Species

    NASA Astrophysics Data System (ADS)

    Prasad, N. S.; Pliutau, D.

    2013-12-01

    We describe a methodology called Cross-Band Relative Absorption (CoBRA) we have implemented to significantly reduce interferences due to variations in atmospheric temperature and pressure in molecular mixing ration measurements [1-4]. The interference reduction is achieved through automatic compensation based on selecting spectral line pairs exhibiting similar evolution behavior under varying atmospheric conditions. The method is applicable to a wide range of molecules including CO2 and CH4 which can be matched with O2 or any other well-mixed atmospheric molecule. Such matching results in automatic simultaneous adjustments of the spectral line shapes at all times with a high precision under varying atmospheric conditions of temperature and pressure. We present the results of our selected CoBRA analysis based on line-by-line calculations and the Modern Era Retrospective Analysis for Research and Applications (MERRA) dataset including more recent evaluation of the error contributions due to water vapor interference effects. References: 1) N. S. Prasad, D. Pliutau, 'Cross-band relative absorption technique for the measurement of molecular mixing ratios.', Optics Express, Vol. 21, Issue 11, pp. 13279-13292 (2013) 2) D. Pliutau and N. S. Prasad, "Cross-band Relative Absorption Technique for Molecular Mixing Ratio Determination," in CLEO: 2013, OSA Technical Digest (online) (Optical Society of America, 2013), paper CW3L.4. 3) Denis Pliutau; Narasimha S. Prasad; 'Semi-empirical validation of the cross-band relative absorption technique for the measurement of molecular mixing ratios',.Proc. SPIE 8731, Laser Radar Technology and Applications XVIII, 87310L (May 20, 2013); doi:10.1117/12.2016661. 4) Denis Pliutau,; Narasimha S. Prasad; 'Comparative analysis of alternative spectral bands of CO2 and O2 for the sensing of CO2 mixing ratios' Proc. SPIE 8718, Advanced Environmental, Chemical, and Biological Sensing Technologies X, 87180L (May 31, 2013); doi:10.1117/12.2016337.

  10. Nonequilibrium thermal transport and its relation to linear response

    NASA Astrophysics Data System (ADS)

    Karrasch, C.; Ilan, R.; Moore, J. E.

    2013-11-01

    We study the real-time dynamics of spin chains driven out of thermal equilibrium by an initial temperature gradient TL≠TR using density matrix renormalization group methods. We demonstrate that the nonequilibrium energy current saturates fast to a finite value if the linear-response thermal conductivity is infinite, i.e., if the Drude weight D is nonzero. Our data suggest that a nonintegrable dimerized chain might support such dissipationless transport (D>0). We show that the steady-state value JE of the current for arbitrary TL≠TR is of the functional form JE=f(TL)-f(TR), i.e., it is completely determined by the linear conductance. We argue for this functional form, which is essentially a Stefan-Boltzmann law in this integrable model; for the XXX ferromagnet, f can be computed via the thermodynamic Bethe ansatz in good agreement with the numerics. Inhomogeneous systems exhibiting different bulk parameters as well as Luttinger liquid boundary physics induced by single impurities are discussed briefly.

  11. Application of GPS for transportation related engineering surveys

    NASA Astrophysics Data System (ADS)

    Merrell, Roger L.

    1986-09-01

    The Texas State Department of Highways and Public Transportation (SDHPT) has been using GPS for over two years to establish primary geodetic reference points for engineering projects and mapping control. In accordance with a Five Year GPS Implementation Plant developed in 1982, four GPS, unmanned, automatic Regional Reference Point (RRP) stations will be installed by September 1, 1986. Five additional stations are planned as justified. Each RRP will consist of a dual frequency GPS receiver that will ultimately track the satellites continuously. Operation of the receiver, telecommunications and other station keeping chores will be handled by a microcomputer. The RRP station network will be controlled through another centrally located microcomputer which is also interfaced with a larger mainframe system. Each RRP is designed to service an area bounded by a 200 KM radius and will act as the “other” receiver for roving field units operating in a GPS differential measurement mode. In order to meet the installation schedule, early decisions are being made concerning satellite tracking rates, operational scenarios, and telecommunications to facilitate development of the basic hardware and software systems. A period of continual enhancement to hardware, software and RRP operational procedures is expected as GPS technology expands.

  12. Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties

    NASA Astrophysics Data System (ADS)

    Swanson, Ryan D.; Binley, Andrew; Keating, Kristina; France, Samantha; Osterman, Gordon; Day-Lewis, Frederick D.; Singha, Kamini

    2015-02-01

    The advection-dispersion equation (ADE) fails to describe commonly observed non-Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual-domain mass-transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct-current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non-Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column-scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more-mobile and less-mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material-dependent and flow-dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.

  13. Hyporheic flow, solute transport, and heat flux in the stream bed around cross-vane restoration structures

    NASA Astrophysics Data System (ADS)

    Gordon, Ryan; Lautz, Laura; Daniluk, Timothy

    2010-05-01

    Natural channel design restoration projects in streams often include cross-vanes, which are low, stone, dam-like structures that span the active channel. The change in water elevation over a cross-vane decreases the static pressure head across the structure from upstream to downstream. It is hypothesized that, as a result, a cross-vane increases the local hyporheic exchange of water through the stream bed. Stream beds are the permeable interface between surface water in streams and groundwater in fluvial aquifers. The hyporheic zone includes the area of the bed where water from the active channel mixes with pore water in shallow sediments and returns to the channel. Channel forms, such as steps, pools, and riffles, intensify the flux of water through the hyporheic zone. Flow paths that redirect stream water through the hyporheic zone increase the residence time of dissolved oxygen, organic material, and nutrients in the stream bed, where enhanced geochemical and biological processes alter the water chemistry and create distinct gradients of redox-sensitive solutes. Hyporheic exchange therefore influences surface water quality, and impacts the health of aquatic species and ecosystems. Few studies have investigated the impact of static restoration structures on hyporheic exchange fluxes or water chemistry. Here we present the results of an investigation of hyporheic flow, solute transport, and heat flux at the locations of two cross-vanes and one natural riffle in a second-order stream in central New York State, USA. Pore water temperatures and water samples from the stream bed were collected in a meter-scale grid at 20-cm depth surrounding the structures and riffle. Temperature was also recorded every 10 minutes for over 2 weeks at several different depths at a subset of points at each site. The time-series temperature data and meter-scale grid temperature measurements were used to calculate vertical water flux rates using an analytical heat transport model. Water

  14. CO2-ECBM related coupled physical and mechanical transport processes

    NASA Astrophysics Data System (ADS)

    Gensterblum, Yves; Satorius, Michael; Busch, Andreas; Krooß, Bernhard

    2013-04-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a sub bituminous A coal from the Surat Basin, Queensland Australia. From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg corrected permeability shows a gas type dependence. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa we observe with increasing mean pressure at lower confining pressure an increase in permeability which we attribute to a cleat aperture widening. The cleat volume compressibility (cf) also shows a dependence on the mean pore pressure. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. This permeability hysteresis is in accordance with results reported by Harpalani and McPherson (1985). The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals

  15. CO2-ECBM related coupled physical and mechanical transport processes

    NASA Astrophysics Data System (ADS)

    Gensterblum, Y.; Sartorius, M.; Busch, A.; Cumming, D.; Krooss, B. M.

    2012-04-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a sub bituminous A coal from the Surat Basin, Queensland Australia. From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg corrected permeability shows a gas type dependence. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa we observe with increasing mean pressure at lower confining pressure an increase in permeability which we attribute to a cleat aperture widening. The cleat volume compressibility (cf) also shows a dependence on the mean pore pressure. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. This permeability hysteresis is in accordance with results reported by Harpalani and McPherson (1985). The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals

  16. Transport of traffic-related aerosols in urban areas.

    PubMed

    Wróbel, A; Rokita, E; Maenhaut, W

    2000-08-10

    This study was undertaken to assess the influence of traffic on particulate air pollution in an urban area, and to characterise the short-range transport of the aerosols generated by traffic. The study was conducted in Kraków, a city located in southern Poland with a population of approximately 800,000. Aerosol samples were collected using automatic sampling equipment at five sites located at different distances from the main road in Kraków, ranging from 5 to 1500 m. The sampling set-up allowed standardisation of the results due to continuous determination of the meteorological parameters (temperature, atmospheric pressure, wind speed and direction, rainfall and humidity). Aerosol particles were separated according to aerodynamic diameter into two size fractions: > 1.9 microm (coarse fraction); and 1.9-72 microm (fine fraction). The concentrations of 27 elements were measured in both size fractions (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Zr, Ba, Pb). The multielement analyses were performed by Particle-Induced X-ray Emission (PIXE) spectrometry. Traffic contribution to particulate air pollution was determined on the basis of 13 elements which were present above the detection limit in all samples (Mg, Al, Si, P, S, K, Ca, Ti, Mn, Fe, Cu, Zn, Pb). It was found that the traffic contribution in the coarse size fraction was approximately 80% up to 150 m from the road; it dropped abruptly by a factor of 2 over a distance of 150-200 m and declined further to 20% at 1500 m from the road. Traffic contribution for the fine particle concentrations of individual elements was 50-70% in the close vicinity of the road (5 m); then there was a decrease, followed by an increase at a greater distance from the road. Possible explanations for this behaviour of the fine particles are given. PMID:10989929

  17. 31 CFR 585.207 - Prohibited transportation-related transactions involving the FRY (S&M).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transactions involving the FRY (S&M). 585.207 Section 585.207 Money and Finance: Treasury Regulations Relating... transactions involving the FRY (S&M). Except as otherwise authorized, the following are prohibited: (a) Any... transportation to or from the FRY (S&M); (b) The provision of transportation to or from the United States by:...

  18. Lipids in Grape Roots in Relation to Chloride Transport 1

    PubMed Central

    Kuiper, Pieter J. C.

    1968-01-01

    A comparison was made between the lipids of the roots of 5 grape rootstocks which differ markedly in the extent to which they permit chloride accumulation in leaves. Monogalactose diglyceride concentration was directly related to chloride accumulation in the leaves of the 5 rootstocks. Phosphatidylcholine and phosphatidylethanolamine were inversely related to chloride accumulation. The variety with the highest chloride accumulation contained an unusually small amount of sterols. A striking negative correlation between content of lignoceric acid and chloride accumulation was observed. The lignoceric acid concentration ranged from 11.9% in the rootstock with the lowest chloride accumulation to 0.8% in the rootstock with the highest chloride accumulation. This fatty acid was found mainly in the phosphatidylcholine and the phosphatidylethanolamine lipid fractions. PMID:16656921

  19. Improvements in magnitude precision, using the statistics of relative amplitudes measured by cross correlation

    NASA Astrophysics Data System (ADS)

    Schaff, David P.; Richards, Paul G.

    2014-04-01

    Standard processing of seismic events for reporting in bulletins is usually done one-at-a time. State-of-the-art relative event methods, often involving cross correlation, are increasingly used and have improved estimates of event parameters for event detection, location and magnitude. This is because relative event techniques can simultaneously reduce measurement error and effects of model error. We show how cross correlation can be used to assign relative magnitudes for neighbouring seismic events distributed over a large region in east Asia and quantify to what extent the uncertainty in these values increases as waveform similarity breaks down. We find that cross correlation works well for magnitude comparison of two events when it is expected that they generate very similar signals even if these may be almost buried in large amounts of noise. This may be the case when investigating repeating earthquakes or nuclear explosions within a few kilometres of each other. Cross correlation is the optimal detector in these cases assuming noise is white and Gaussian, and also provides the least-squares solution for the relative amplitudes. However, when the waveform similarity of the underlying signals breaks down, due to interevent separation distance, source time function differences or focal mechanism differences, these assumptions are no longer valid and a bias is introduced into the relative magnitude measurement. This bias due to degradation of waveform similarity is modelled here with synthetics and an analytic expression for it is derived based on three terms-the cross-correlation coefficient (CC), and the signal-to-noise ratio (SNR) of the larger and smaller events. The analytic expression is a good match to the observed bias in the data. If the equation for relative magnitude is rewritten to correct for the bias due to the CC, a new equation results which is simply the log of the ratio of the L2 norms. The bias due to SNRs is still present because the observed

  20. Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion

    USGS Publications Warehouse

    Disney, M.R.; Hellgren, E.C.; Davis, C.A.; Leslie, David M., Jr.; Engle, David M.

    2008-01-01

    Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention than relationships to other metrics of fragmentation, particularly edge characteristics. We tested the hypothesis that relative abundance of mesopredators (e.g., raccoons and Virginia opossums) was related negatively to size of forest patch. We delineated 15 patches of oak (Quercus) forest ranging from 0.2 to 55.3 ha within a grassland-woodland mosaic in the cross-timbers ecoregion of Oklahoma. Scent stations and live traps within these patches were used to index relative abundance of mesopredators in summers 2003 and 2004. Both indices of relative abundance were related weakly and negatively to area of forest patch. However, rate of capture and visitation to scent station were not correlated consistently throughout the study. Our results suggested that the two methods to index abundance provided separate information on functional and numerical responses to size of patch. Our evidence that mesopredators within the cross timbers were more likely to be in smaller patches of oak forest may have implications to success of avian nesting in these patches.

  1. Barriers and Bridges to Positive Cross-Ethnic Relations: African American and White Parent Socialization Beliefs and Practices.

    ERIC Educational Resources Information Center

    Hamm, Jill V.

    2001-01-01

    Using interviews and focus groups, lower and middle socioeconomic status (SES) African American parents and middle SES white parents discussed their objectives regarding cross-ethnic relations and how they helped their children forge positive cross-ethnic relations. The groups relied on different methods to promote socialization. Parents' efforts…

  2. Interfaces MATXS Cross-Section Libraries to Nuclear Transport Codes for Fusion Systems Analysis.

    Energy Science and Technology Software Center (ESTSC)

    1985-04-10

    Version: 00 TRANSX-CTR is a computer code that reads nuclear data from a library in MATXS format and produces transport tables with many discrete-ordinates (Sn) and diffusion codes. Tables can be produced for neutron, photon, or coupled transport. Options include adjoint tables, mixtures, self-shielding, group collapse, homogenization, thermal upscatter, prompt or steady-state fission, transport corrections, elastic removal corrections, and flexible response-function edits. The ability to prepare coupled tables and response edits for heating, damage, gasmore » production, and delayed activity makes TRANSX-CTR especially useful for fusion reactor studies.« less

  3. Determination of the Relative Two-photon Absorption Cross-section Between Xenon and Hydrogen

    NASA Astrophysics Data System (ADS)

    Elliott, Drew; Scime, Earl; McCarren, Dustin; Vandervort, Robert; Soderholm, Mark

    2014-10-01

    Two-photon Absorption Laser Induced Fluorescence (TALIF) is a non-perturbative method for measuring the density and temperature of neutral hydrogen in a fusion plasma. Calibration of a TALIF system, for absolute density measurements, requires a measurement of a known density of particles under controlled conditions. Since hydrogen is diatomic, hydrogen TALIF system calibration requires measurements of target cold monatomic gas with a two-photon transition from the ground state and fluorescence decay at accessible energies. Here we present single-sided TALIF (angular momentum change of 2) measurements of a new transition in xenon with absorption and emission wavelengths nearly identical to those of the hydrogen TALIF sequence (the n = 3 to n = 2 emission in hydrogen is at 656.27 nm whereas it is at 655.99 nm in xenon). The xenon calibration approach provides the first opportunity for absolute calibration of Doppler-free (angular momentum change of 0) hydrogen TALIF. We first measure the relative TALIF absorption cross section between xenon and krypton and then use the known cross section ratio between the krypton and hydrogen transitions to calculate the relative xenon-hydrogen cross section. Single isotope xenon samples are used to remove the confounding factors of isotopic and hyperfine splitting.

  4. Cross-cultural generalizability of personality dimensions: relating indigenous and imported dimensions in two cultures.

    PubMed

    Katigbak, M S; Church, A T; Akamine, T X

    1996-01-01

    The cross-cultural generalizability of personality dimensions was investigated by (a) identifying indigenous Philippine dimensions, (b) testing the cross-cultural replicability of the NEO 5-factor model (P. T. Costa & R.R. McCrae, 1992), and (c) relating Philippine and Western dimensions in Philippine and U.S. samples of college students. Filipino self-ratings (N = 536) on indigenous items were factor analyzed, and 6 Philippine dimensions were obtained. Conclusions about the replicability of the 5-factor model in the Philippines (N = 432) depended on whether exploratory, Procrustes, or confirmatory factor methods were used. In regression and joint factor analyses, moderate to strong associations were found between the Philippine dimensions and (a) dimensions from the 5-factor model in both Philippine (N = 387) and U.S. (N = 610) samples, and (b) the Tellegen model (A. Tellegen, 1985; A. Tellegen & N.G. Waller, in press) in a U.S. sample (N = 603). PMID:8558409

  5. Transport analysis of measured neutron leakage spectra from spheres as tests of evaluated high energy cross sections

    NASA Technical Reports Server (NTRS)

    Bogart, D. D.; Shook, D. F.; Fieno, D.

    1973-01-01

    Integral tests of evaluated ENDF/B high-energy cross sections have been made by comparing measured and calculated neutron leakage flux spectra from spheres of various materials. An Am-Be (alpha,n) source was used to provide fast neutrons at the center of the test spheres of Be, CH2, Pb, Nb, Mo, Ta, and W. The absolute leakage flux spectra were measured in the energy range 0.5 to 12 MeV using a calibrated NE213 liquid scintillator neutron spectrometer. Absolute calculations of the spectra were made using version 3 ENDF/B cross sections and an S sub n discrete ordinates multigroup transport code. Generally excellent agreement was obtained for Be, CH2, Pb, and Mo, and good agreement was observed for Nb although discrepancies were observed for some energy ranges. Poor comparative results, obtained for Ta and W, are attributed to unsatisfactory nonelastic cross sections. The experimental sphere leakage flux spectra are tabulated and serve as possible benchmarks for these elements against which reevaluated cross sections may be tested.

  6. 49 CFR 614.101 - Cross-reference to management systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Cross-reference to management systems. 614.101 Section 614.101 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRANSPORTATION INFRASTRUCTURE MANAGEMENT § 614.101 Cross-reference to management systems....

  7. Negative ion clusters in oxygen: collision cross sections and transport coefficients

    NASA Astrophysics Data System (ADS)

    de Urquijo, J.; Bekstein, A.; Ducasse, O.; Ruíz-Vargas, G.; Yousfi, M.; Benhenni, M.

    2009-12-01

    Using a pulsed Townsend experiment, we have observed the formation of two negative ion species in oxygen over the pressure range 100-600 torr, and the density-normalised electric field strength, E/N, from 2 to 14 Td. The peculiar shape of these transients has led us to propose a scheme of three-body ion-molecule reactions leading to the formation of O4 - and O6 -, which is substantiated by a curve fitting procedure. The resulting mobility data of these two ionic species have been used to calculate their respective momentum transfer collision cross sections, together with the dissociation cross sections that are needed to extend the range of calculation of mobility and diffusion (transverse and longitudinal) to 1000 Td. These calculations were based on an optimised Monte Carlo algorithm, using collision cross sections obtained from a JWKB approximation (Jeffreys-Wentzel-Kramers-Brillouin) or taken from literature.

  8. 29 CFR 780.908 - Relation of employee's work to specified transportation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Relation of employee's work to specified transportation. 780.908 Section 780.908 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING...

  9. 29 CFR 780.908 - Relation of employee's work to specified transportation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Relation of employee's work to specified transportation. 780.908 Section 780.908 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS EXEMPTIONS APPLICABLE TO AGRICULTURE, PROCESSING...

  10. Dispersion relations with crossing symmetry for {pi}{pi} D- and F-wave amplitudes

    SciTech Connect

    Kaminski, R.

    2011-04-01

    A set of once subtracted dispersion relations with imposed crossing symmetry condition for the {pi}{pi} D- and F-wave amplitudes is derived and analyzed. An example of numerical calculations in the effective two-pion mass range from the threshold to 1.1 GeV is presented. It is shown that these new dispersion relations impose quite strong constraints on the analyzed {pi}{pi} interactions and are very useful tools to test the {pi}{pi} amplitudes. One of the goals of this work is to provide a complete set of equations required for easy use. Full analytical expressions are presented. Along with the well-known dispersion relations successful in testing the {pi}{pi} S- and P-wave amplitudes, those presented here for the D and F waves give a complete set of tools for analyses of the {pi}{pi} interactions.

  11. Predicting organic hydrogen atom transfer rate constants using the Marcus cross relation

    PubMed Central

    Warren, Jeffrey J.; Mayer, James M.

    2010-01-01

    Chemical reactions that involve net hydrogen atom transfer (HAT) are ubiquitous in chemistry and biology, from the action of antioxidants to industrial and metalloenzyme catalysis. This report develops and validates a procedure to predict rate constants for HAT reactions of oxyl radicals (RO•) in various media. Our procedure uses the Marcus cross relation (CR) and includes adjustments for solvent hydrogen-bonding effects on both the kinetics and thermodynamics of the reactions. Kinetic solvent effects (KSEs) are included by using Ingold’s model, and thermodynamic solvent effects are accounted for by using an empirical model developed by Abraham. These adjustments are shown to be critical to the success of our combined model, referred to as the CR/KSE model. As an initial test of the CR/KSE model we measured self-exchange and cross rate constants in different solvents for reactions of the 2,4,6-tri-tert-butylphenoxyl radical and the hydroxylamine 2,2′-6,6′-tetramethyl-piperidin-1-ol. Excellent agreement is observed between the calculated and directly determined cross rate constants. We then extend the model to over 30 known HAT reactions of oxyl radicals with OH or CH bonds, including biologically relevant reactions of ascorbate, peroxyl radicals, and α-tocopherol. The CR/KSE model shows remarkable predictive power, predicting rate constants to within a factor of 5 for almost all of the surveyed HAT reactions. PMID:20215463

  12. Built Environment and Active Transport to School (BEATS) Study: protocol for a cross-sectional study

    PubMed Central

    Mandic, Sandra; Williams, John; Moore, Antoni; Hopkins, Debbie; Flaherty, Charlotte; Wilson, Gordon; García Bengoechea, Enrique; Spence, John C

    2016-01-01

    Introduction Active transport to school (ATS) is a convenient way to increase physical activity and undertake an environmentally sustainable travel practice. The Built Environment and Active Transport to School (BEATS) Study examines ATS in adolescents in Dunedin, New Zealand, using ecological models for active transport that account for individual, social, environmental and policy factors. The study objectives are to: (1) understand the reasons behind adolescents and their parents' choice of transport mode to school; (2) examine the interaction between the transport choices, built environment, physical activity and weight status in adolescents; and (3) identify policies that promote or hinder ATS in adolescents. Methods and analysis The study will use a mixed-method approach incorporating both quantitative (surveys, anthropometry, accelerometers, Geographic Information System (GIS) analysis, mapping) and qualitative methods (focus groups, interviews) to gather data from students, parents, teachers and school principals. The core data will include accelerometer-measured physical activity, anthropometry, GIS measures of the built environment and the use of maps indicating route to school (students)/work (parents) and perceived safe/unsafe areas along the route. To provide comprehensive data for understanding how to change the infrastructure to support ATS, the study will also examine complementary variables such as individual, family and social factors, including student and parental perceptions of walking and cycling to school, parental perceptions of different modes of transport to school, perceptions of the neighbourhood environment, route to school (students)/work (parents), perceptions of driving, use of information communication technology, reasons for choosing a particular school and student and parental physical activity habits, screen time and weight status. The study has achieved a 100% school recruitment rate (12 secondary schools). Ethics and

  13. The initiation, propagation, and effect of matrix microcracks in cross-ply and related laminates

    NASA Technical Reports Server (NTRS)

    Nairn, John A.; Hu, Shoufeng; Liu, Siulie; Bark, Jong

    1991-01-01

    Recently, a variational mechanics approach was used to determine the thermoelastic stress state in cracked laminates. Described here is a generalization of the variational mechanics techniques to handle other cross-ply laminates, related laminates, and to account for delaminations emanating from microcrack tips. Microcracking experiments on Hercules 3501-6/AS4 carbon fiber/epoxy laminates show a staggered cracking pattern. These results can be explained by the variational mechanics analysis. The analysis of delaminations emanating from microcrack tips has resulted in predictions about the structural and material variables controlling competition between microcracking and delamination failure modes.

  14. Cross identification of 238 galaxies and use of a colour magnitude relation in the coma cluster

    NASA Astrophysics Data System (ADS)

    Mazure, A.; Proust, D.; Mathez, G.; Mellier, Y.

    1988-12-01

    A catalogue of 238 galaxies is obtained by the cross identification of data from Kent and Gunn (1982), Godwin and Peach (1977) and Godwin, Metcalfe and Peach (1983). It contains the radial velocities, bvr magnitudes, colour indices, isophotal radii and other characteristics of individual galaxies. This leads to the definition of various samples of radial velocities complete to various limiting magnitudes depending on radius. The use of the colour magnitude relation is discussed to define a class of 1340 objects ({sequence} objects) likely to belong to the cluster from their photometry only.

  15. Double Trouble at High Density: Cross-Level Test of Resource-Related Adaptive Plasticity and Crowding-Related Fitness

    PubMed Central

    Gergs, André; Preuss, Thomas G.; Palmqvist, Annemette

    2014-01-01

    Population size is often regulated by negative feedback between population density and individual fitness. At high population densities, animals run into double trouble: they might concurrently suffer from overexploitation of resources and also from negative interference among individuals regardless of resource availability, referred to as crowding. Animals are able to adapt to resource shortages by exhibiting a repertoire of life history and physiological plasticities. In addition to resource-related plasticity, crowding might lead to reduced fitness, with consequences for individual life history. We explored how different mechanisms behind resource-related plasticity and crowding-related fitness act independently or together, using the water flea Daphnia magna as a case study. For testing hypotheses related to mechanisms of plasticity and crowding stress across different biological levels, we used an individual-based population model that is based on dynamic energy budget theory. Each of the hypotheses, represented by a sub-model, is based on specific assumptions on how the uptake and allocation of energy are altered under conditions of resource shortage or crowding. For cross-level testing of different hypotheses, we explored how well the sub-models fit individual level data and also how well they predict population dynamics under different conditions of resource availability. Only operating resource-related and crowding-related hypotheses together enabled accurate model predictions of D. magna population dynamics and size structure. Whereas this study showed that various mechanisms might play a role in the negative feedback between population density and individual life history, it also indicated that different density levels might instigate the onset of the different mechanisms. This study provides an example of how the integration of dynamic energy budget theory and individual-based modelling can facilitate the exploration of mechanisms behind the regulation

  16. Electron Transport in Multi-Terminal Graphene Nanodevice with Inclined Cross Structures

    NASA Astrophysics Data System (ADS)

    Ye, En-Jia; Shi, Yi-Jian; Zhao, Xuean

    2014-12-01

    The DC and AC transport properties are investigated in multi-terminal graphene nanoribbon (GNR) devices. The devices are composed of three or four graphene ribbons connected with different angles. It is found that DC and AC conductances depend on the structural configurations and ribbon properties. In the vicinity of Dirac point, the intersection of graphene ribbons forms band mixing and results in resonant or anti-resonant states. The edge and width, as well as, the angles of the graphene ribbons influence the DC and AC transport properties drastically. These properties can be used to build future graphene-based nanoelectronics.

  17. Transport cross sections based on a screened interaction potential: Comparison of classical and quantum-mechanical results

    SciTech Connect

    Vincent, R.; Juaristi, J.I.

    2005-06-15

    Standard classical and quantum-mechanical methods are used to characterize the momentum-transfer cross section needed in energy-loss calculations and simulations for heavy, swift charges moving in an electron gas. By applying a well-known, finite-range screened Coulombic potential energy to model the two-body collision, the quantitative applicability range of the classical cross section is investigated as a function of charge (Z), screening length (R), and scattering relative velocity (v). The a posteriori condition (Z/R)/v{sup 2}<1, as an upper bound for heavy charges, is deduced for this applicability range from the comparative study performed.

  18. Towards an explanation of age-related difficulties in crossing a two-way street.

    PubMed

    Dommes, Aurélie; Lay, Tristan Le; Vienne, Fabrice; Dang, Nguyen-Thong; Beaudoin, Alexandra Perrot; Do, Manh Cuong

    2015-12-01

    Crossing a two-way street is a complex task that involves visual, cognitive and motor abilities, all of which are known to decline with ageing. In particular, older pedestrians may experience difficulties when crossing two-way streets because of incorrect gap acceptance choices and impossible or unperceived evasive actions. To understand the overrepresentation of older pedestrians in crash statistics, several experimental studies have sought to identify traffic-related factors as well as those related to the abilities of the individuals themselves. However, none of these studies has required participants to actually walk across an experimental two-way street with curbs, which is a particularly challenging situation for older pedestrians. To fill this research gap, a quasi-experiment was conducted in a simulator including a total of 58 healthy aged participants (25 younger-old [age 60-72] and 33 older-old [age 72-92]) and 25 young adults (aged 18-25 years). Participants carried out a street-crossing task in a simulated two-way traffic environment; curbs were present on both sides of the experimental street. Participants also undertook a battery of tests to assess their visual and cognitive abilities. In addition, during the experiment, the participants' gait parameters were recorded. In line with earlier findings, the older-old group of participants made a higher number of decisions that led to collisions with approaching cars compared with the other groups. The two groups of older participants experienced specific difficulties when vehicles were in the far lane or when they approached rapidly. A regression analysis identified visual acuity, speed of processing (assessed using the UFOV(®) test), and step length as significant predictors of collisions. Our results have implications for understanding the difficulties experienced by older pedestrians and allow to draw up several recommendations for improving their safety. PMID:26476193

  19. Review of Transporter-Related Postmarketing Requirement or Postmarketing Commitment Studies.

    PubMed

    Fan, Ying; Sun, Bo; Agarwal, Sheetal; Zhang, Lei

    2016-07-01

    The objectives of this report are to summarize the content and status of transporter-related postmarketing requirement (PMR)/postmarketing commitment (PMC) studies in new drug applications (NDAs) approved by the U.S. Food and Drug Administration (FDA) and to discuss the reasons for requesting such studies and the impact of PMR/PMC study results on labeling to guide the optimal use of the drugs. Multiple data sources were searched to collect information on transporter-related PMR/PMC studies between January 1999 and May 2015. A total of 40 transporter-related PMR/PMC study requests were issued for 35 NDAs. Among these PMR/PMC studies, 27 requested studies related to P-glycoprotein. As of May 31, 2015, 34 transporter-related PMR/PMC studies (85%) are considered "fulfilled" (per the FDA's PMR/PMC website), and 22 (65%) resulted in labeling updates. The majority of the PMR/PMC studies are for drugs in the therapeutic areas of anti-infectives, oncology, and neurology. The results from PMR/PMC studies are important for dosing optimization and are often included in the updated labeling. Because a significant lag time is anticipated between drug approval and PMR/PMC fulfillment, NDA applicants are encouraged to include transporter-related assessments in clinical drug development programs for drug products. PMID:27385175

  20. Microsatellite primers for Camissoniopsis cheiranthifolia (Onagraceae) and cross-amplification in related species1

    PubMed Central

    López-Villalobos, Adriana; Samis, Karen E.; Eckert, Christopher G.

    2014-01-01

    • Premise of the study: We developed 24 nuclear microsatellite primers from an enriched genomic library for the Pacific coastal dune endemic Camissoniopsis cheiranthifolia to study the consequences of mating system differentiation, the genetics of species’ range limits, and hybridization with its closest sister taxon, C. bistorta. • Methods and Results: Twenty-four primer pairs were developed and characterized in four populations of C. cheiranthifolia and one population of C. bistorta. We also tested eight additional taxa for cross-amplification. The average number of alleles per locus per species was 4.3 and 6.0, respectively. The number of loci that amplified and were variable within the eight related taxa ranged from six to 17. • Conclusions: These markers will be useful in studying mating system evolution, the genetic structure of species’ ranges, hybridization, and the provenance of material used for habitat restoration in C. cheiranthifolia, C. bistorta, and related species. PMID:25309839

  1. Relaxation compensated and intensity recovered dynamics of cross polarization in the frame of reciprocity relation

    NASA Astrophysics Data System (ADS)

    Shu, Wenfang; Zhang, Shanmin

    2011-08-01

    Through combing the scheme of TORQUE (by Tekely et al.) with cross depolarization (CDP), we derived a relaxation compensated and intensity recovered Hartmann-Hahn CP dynamics in the frame of reciprocity relation. As a result, the CP dynamics of TORQUE (CP T1ρQ( t)) emerges from the T1ρ damped dynamics and upon normalization of the intensities by the reciprocity relation, it is perfectly symmetric with respect to the CDP( t). Along with an enhancement factor of CP defined as η( t) = [1-CDP(t)](γI/γ) and a scaling factor between two peak intensities, λ(t')=PI(t')/PI T1ρQ( t'), this method provides a convenient, robust, and quantitative measure of CP spectra.

  2. Adolescents’ Pregnancy Intentions, Wantedness, and Regret: Cross-Lagged Relations With Mental Health and Harsh Parenting

    PubMed Central

    East, Patricia L.; Chien, Nina C.; Barber, Jennifer S.

    2011-01-01

    The authors used cross-lagged analyses to examine the across-time influences on and consequences of adolescents’ pregnancy intentions, wantedness, and regret. One hundred pregnant Latina adolescents were studied during pregnancy and at 6 and 12 months postpartum. The results revealed 4 main findings: (a) similar to what has been found in adult women, adolescents’ lower prenatal pregnancy intendedness and wantedness predicted initial difficulties in parenting; (b) frequent depression symptoms predicted subsequent lower pregnancy intendedness and wantedness; (c) adolescents’ poor mental health and harsh parenting of their child predicted subsequent higher childbearing regret, and (d) high childbearing regret and parenting stress were reciprocally related across time. In addition, adolescents’ wantedness of their pregnancy declined prenatally to postbirth, and strong pregnancy intendedness and wantedness were not concurrently related to adolescents’ poor prenatal mental health. The findings reveal how adolescents’ thoughts and feelings about their pregnancies are influenced by and predictive of their mental health and parenting experiences. PMID:22544975

  3. Gravity-Related Transport Process in Off-Axis Sputtering Deposition

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Su, Ching-Hua; Lehozeku, S. L.

    2000-01-01

    In the synthesis of epitaxial oxide films, reactive off-axis sputtering deposition techniques have demonstrated the advantages of fabricating high quality epitaxial films. Due to the collisions between the sputtered species and the residue gases, the kinetic energy of species was reduced and the transport of depositing species changed from a ballistic movement to a diffusive drift in which the transport species were almost thermalized. A gravity effect could appear in the transport process. Three transport regimes were observed when the growth pressures vary from 5 mTorr to 150 mTorr. Film growth rate, depositing orientations, crystal structure, surface morphology, and compositions were characterized. A gravity related phenomenon was revealed in film growth at the relative low growth pressures.

  4. Transport properties and Stokes-Einstein relation in Al-rich liquid alloys.

    PubMed

    Jakse, N; Pasturel, A

    2016-06-28

    We use ab initio molecular dynamics simulations to study the transport properties and the validity of the Stokes-Einstein relation in Al-rich liquid alloys with Ni, Cu, and Zn as alloying elements. First, we show that the composition and temperature dependence of their transport properties present different behaviors, which can be related to their local structural ordering. Then, we evidence that the competition between the local icosahedral ordering and the local chemical ordering may cause the breakdown of the Stokes-Einstein relation even in the liquid phase. We demonstrate that this breakdown can be captured by entropy-scaling relationships developed by Rosenfeld and using the two-body excess entropy. Our findings provide a unique framework to study the relation between structure, thermodynamics, and dynamics in metallic melts and pave the way towards the explanation of various complex transport properties in metallic melts. PMID:27369522

  5. 31 CFR 538.209 - Prohibited transportation-related transactions involving Sudan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Prohibited transportation-related transactions involving Sudan. 538.209 Section 538.209 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY...

  6. Effective Potential Energies and Transport Cross Sections for Atom-Molecule Interactions of Nitrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, Jim (Technical Monitor)

    2001-01-01

    The potential energy surfaces for H2-N and N2-N interactions are calculated by accurate ab initio methods and applied to determine transport data. The results confirm that an effective potential energy for accurately determining transport properties can be calculated using a single orientation. A simple method is developed to determine the dispersion coefficients of effective potential energies Effective potential energies required for O2-O collisions are determ=ined. The H2-N, N2-N, O2-H, and O2-O collision integrals are calculated and tabulated for a large range of temperatures. The theoretical values of the N2-N and O2-O diffusion coefficients compare well with measured data available at room temperature.

  7. Cross-field transport and pitch-angle anisotropy of solar energetic particles in MHD turbulence

    NASA Astrophysics Data System (ADS)

    Fraschetti, F.

    2016-01-01

    Recent modelling of solar energetic particles (SEPs) propagation through the heliospheric turbulence, also discussed in this workshop, has investigated the role of the pitch-angle scattering and the perpendicular transport in spreading particles in heliolongitude, as shown by multi-spacecraft measurements (STEREO A/B, ACE, SOHO, etc.) at 1 AU in various energy ranges. In some events the first-order pitch-angle anisotropy of the particles distribution is not-negligible. We calculate the average perpendicular displacement due to the gradient/curvature drift in an inhomogeneous turbulence accounting for pitch-angle dependence for two MHD turbulence models: (a) 3-D isotropic, (b) anisotropic as conjectured by Goldreich-Sridhar. We find in both cases that the drift scales as (1 - μ2)2 with the cosine of pitch-angle μ, in contrast with previous models for transport of SEPs. This result can impact the models of propagation of SEPs through the heliosphere.

  8. Crossed fiber optic Bessel beams for curvilinear optofluidic transport of dielectric particles.

    PubMed

    Kim, Jongki; Lee, Sungrae; Jeong, Yoonseob; Kim, Jun-Ki; Jung, Yongmin; Merenda, Fabrice; Salathè, Renè-Paul; Shin, Jeon-Soo; Oh, Kyunghwan

    2013-10-01

    Due to its unique non-diffracting and self-reconstructing nature, Bessel beams have been successfully adopted to trap multiple particles along the beam's axial direction. However, prior bulk-optic based Bessel beams have a fundamental form-factor limitation for in situ, in-vitro, and in-vivo applications. Here we present a novel implementation of Fourier optics along a single strand of hybrid optical fiber in a monolithic manner that can generate pseudo Bessel beam arrays in two-dimensional space. We successfully demonstrate unique optofluidic transport of the trapped dielectric particles along a curvilinear optical route by multiplexing the fiber optic pseudo Bessel beams. The proposed technique can form a new building block to realize reconfigurable optofluidic transportation of particulates that can break the limitations of both prior bulk-optic Bessel beam generation techniques and conventional microfluidic channels. PMID:24104217

  9. Cross-language activation of morphological relatives in cognates: the role of orthographic overlap and task-related processing

    PubMed Central

    Mulder, Kimberley; Dijkstra, Ton; Baayen, R. Harald

    2015-01-01

    We considered the role of orthography and task-related processing mechanisms in the activation of morphologically related complex words during bilingual word processing. So far, it has only been shown that such morphologically related words (i.e., morphological family members) are activated through the semantic and morphological overlap they share with the target word. In this study, we investigated family size effects in Dutch-English identical cognates (e.g., tent in both languages), non-identical cognates (e.g., pil and pill, in English and Dutch, respectively), and non-cognates (e.g., chicken in English). Because of their cross-linguistic overlap in orthography, reading a cognate can result in activation of family members both languages. Cognates are therefore well-suited for studying mechanisms underlying bilingual activation of morphologically complex words. We investigated family size effects in an English lexical decision task and a Dutch-English language decision task, both performed by Dutch-English bilinguals. English lexical decision showed a facilitatory effect of English and Dutch family size on the processing of English-Dutch cognates relative to English non-cognates. These family size effects were not dependent on cognate type. In contrast, for language decision, in which a bilingual context is created, Dutch and English family size effects were inhibitory. Here, the combined family size of both languages turned out to better predict reaction time than the separate family size in Dutch or English. Moreover, the combined family size interacted with cognate type: the response to identical cognates was slowed by morphological family members in both languages. We conclude that (1) family size effects are sensitive to the task performed on the lexical items, and (2) depend on both semantic and formal aspects of bilingual word processing. We discuss various mechanisms that can explain the observed family size effects in a spreading activation framework

  10. 49 CFR 1111.4 - Answers and cross complaints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 8 2012-10-01 2012-10-01 false Answers and cross complaints. 1111.4 Section 1111.4 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE COMPLAINT AND INVESTIGATION PROCEDURES §...

  11. 49 CFR 1111.4 - Answers and cross complaints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 8 2011-10-01 2011-10-01 false Answers and cross complaints. 1111.4 Section 1111.4 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE COMPLAINT AND INVESTIGATION PROCEDURES §...

  12. 49 CFR 1111.4 - Answers and cross complaints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 8 2013-10-01 2013-10-01 false Answers and cross complaints. 1111.4 Section 1111.4 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE COMPLAINT AND INVESTIGATION PROCEDURES §...

  13. 49 CFR 1111.4 - Answers and cross complaints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 8 2014-10-01 2014-10-01 false Answers and cross complaints. 1111.4 Section 1111.4 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE COMPLAINT AND INVESTIGATION PROCEDURES §...

  14. Wet Deposition of Radon Decay Products and its Relation with Long-Range Transported Radon

    SciTech Connect

    Yamazawa, H.; Matsuda, M.; Moriizumi, J.; Iida, T.

    2008-08-07

    It was shown by a series of observations of wet deposition of radon decay products at Nagoya, Japan that extremely high deposition rate events were associated with convective precipitation under presence of continental air mass aloft. Atmospheric transport simulations showed that the high deposition rate events were caused by continental radon transported within a relatively thin layer from 1 to 3 km above sea level.

  15. Modeling cross-field transport of solar energetic particles including solar wind effects

    NASA Astrophysics Data System (ADS)

    Lampa, Florian; Kallenrode, May-Britt

    Under consideration of solar wind effects, we have extended the Ruffolo's equation of focused transport for solar energetic particles to accommodate perpendicular transport in the ecliptic plane, and made a different approach concerning the reference frame. Numerically, the additional transport term is solved with the implicit and stable Laasonen scheme. In parameter studies and fits to observations for typical ratios κ⊥ /κ ranging between 0.02 and 0.1 at 1 AU as suggested in numerous studies (e.g. non-linear guiding-center theory) and a scaling of κ⊥ with r2 as suggested from the random walk of field lines as well as from numerical simulations, we find that azimuthal spread as well as the variation of maximum intensities with longitude is comparable to the ones inferred from multi-spacecraft observations. Implications for the interpretation of the observed intensity and anisotropy time profiles and consequences for our understanding of particle propagation and acceleration in space will be discussed.

  16. Defining and relating biomedical terms: towards a cross-language morphosemantics-based system.

    PubMed

    Namer, Fiammetta; Baud, Robert

    2007-01-01

    This paper addresses the issue of how semantic information can be automatically assigned to compound terms, i.e. both a definition and a set of semantic relations. This is particularly crucial when elaborating multilingual databases and when developing cross-language information retrieval systems. The paper shows how morphosemantics can contribute in the constitution of multilingual lexical networks in biomedical corpora. It presents a system capable of labelling terms with morphologically related words, i.e. providing them with a definition, and grouping them according to synonymy, hyponymy and proximity relations. The approach requires the interaction of three techniques: (1) a language-specific morphosemantic parser, (2) a multilingual table defining basic relations between word roots and (3) a set of language-independent rules to draw up the list of related terms. This approach has been fully implemented for French, on an about 29,000 terms biomedical lexicon, resulting to more than 3000 lexical families. A validation of the results against a manually annotated file by experts of the domain is presented, followed by a discussion of our method. PMID:16814603

  17. Drug use, mental health and problems related to crime and violence: cross-sectional study1

    PubMed Central

    Claro, Heloísa Garcia; de Oliveira, Márcia Aparecida Ferreira; Bourdreaux, Janet Titus; Fernandes, Ivan Filipe de Almeida Lopes; Pinho, Paula Hayasi; Tarifa, Rosana Ribeiro

    2015-01-01

    Objective: to investigate the correlation between disorders related to the use of alcohol and other drugs and symptoms of mental disorders, problems related to crime and violence and to age and gender. Methods: cross-sectional descriptive study carried out with 128 users of a Psychosocial Care Center for Alcohol and other Drugs, in the city of São Paulo, interviewed by means of the instrument entitled Global Appraisal of Individual Needs - Short Screener. Univariate and multiple linear regression models were used to verify the correlation between the variables. Results: using univariate regression models, internalizing and externalizing symptoms and problems related to crime/violence proved significant and were included in the multiple model, in which only the internalizing symptoms and problems related to crime and violence remained significant. Conclusions: there is a correlation between the severity of problems related to alcohol use and severity of mental health symptoms and crime and violence in the study sample. The results emphasize the need for an interdisciplinary and intersectional character of attention to users of alcohol and other drugs, since they live in a socially vulnerable environment. PMID:26626010

  18. THE ROLE OF CROSS-SHOCK POTENTIAL ON PICKUP ION SHOCK ACCELERATION IN THE FRAMEWORK OF FOCUSED TRANSPORT THEORY

    SciTech Connect

    Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K.

    2013-10-20

    The focused transport theory is appropriate to describe the injection and acceleration of low-energy particles at shocks as an extension of diffusive shock acceleration (DSA). In this investigation, we aim to characterize the role of cross-shock potential (CSP) originated in the charge separation across the shock ramp on pickup ion (PUI) acceleration at various types of shocks with a focused transport model. The simulation results of energy spectrum and spatial density distribution for the cases with and without CSP added in the model are compared. With sufficient acceleration time, the focused transport acceleration finally falls into the DSA regime with the power-law spectral index equal to the solution of the DSA theory. The CSP can affect the shape of the spectrum segment at lower energies, but it does not change the spectral index of the final power-law spectrum at high energies. It is found that the CSP controls the injection efficiency which is the fraction of PUIs reaching the DSA regime. A stronger CSP jump results in a dramatically improved injection efficiency. Our simulation results also show that the injection efficiency of PUIs is mass-dependent, which is lower for species with a higher mass. In addition, the CSP is able to enhance the particle reflection upstream to produce a stronger intensity spike at the shock front. We conclude that the CSP is a non-negligible factor that affects the dynamics of PUIs at shocks.

  19. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS... and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating to transportation of hazardous and nuclear waste? Sections 170.900 through 170.907 on transportation of nuclear...

  20. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS... and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating to transportation of hazardous and nuclear waste? Sections 170.900 through 170.907 on transportation of nuclear...

  1. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS... and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating to transportation of hazardous and nuclear waste? Sections 170.900 through 170.907 on transportation of nuclear...

  2. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS... and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating to transportation of hazardous and nuclear waste? Sections 170.900 through 170.907 on transportation of nuclear...

  3. 25 CFR 170.900 - What is the purpose of the provisions relating to transportation of hazardous and nuclear waste?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... transportation of hazardous and nuclear waste? 170.900 Section 170.900 Indians BUREAU OF INDIAN AFFAIRS... and Nuclear Waste Transportation § 170.900 What is the purpose of the provisions relating to transportation of hazardous and nuclear waste? Sections 170.900 through 170.907 on transportation of nuclear...

  4. Cross-Cultural Perspectives of Service Quality and Risk in Air Transportation

    NASA Technical Reports Server (NTRS)

    Cunningham, Lawrence F.; Young, Clifford E.; Lee, Moonkyu

    2002-01-01

    This study compares US and Korean customers in terms of their perceptions of airline service quality based on SERVPERF and industry-based measures, as well as their perceptions of risks involved in the airline choice. SERVPERF is a set of multi-dimensional measures of customer evaluations of service quality. The results indicate that: (1) US passengers are generally more satisfied with their airline service than Korean customers on most of the SERVPERF dimensions; (2) Koreans are generally more satisfied with the bumping procedures whereas US participants feel more satisfied with the airline's baggage handling, operations/safety, and connections; and (3) US participants perceive higher levels of performance and financial risks whereas Koreans feel greater social risk in choosing an airline. This study also examines the SERVPERF, industry-based measure, and perceived risk in predicting customer satisfaction with, and intention to repatronize the airline. The results suggest that US customers consider service reliability, in-flight comfort, and connections as the key factors determining satisfaction with airline service whereas Korean passengers generally regard reliability, assurance, and risk factors as predictors of satisfaction. The determining factors of customer intention to repatronize the airline are reliability and empathy for US, and reliability and overall risk for Korean customers. The study demonstrates the applicability of SERVPERF as a cross-cultural tool and indicates the importance of perceived risk in cross-cultural studies.

  5. Distribution of transport injury and related risk behaviours in a large national cohort of Thai adults

    PubMed Central

    Stephan, Karen; Kelly, Matthew; Mcclure, Rod; Seubsman, Sam-ang; Yiengprugsawan, Vasoontara; Bain, Christopher; Sleigh, Adrian

    2011-01-01

    Background A major barrier to addressing the problem of transport injury in low to middle-income countries is the lack of information regarding the incidence of traffic crashes and the demographic, behavioural and socio-economic determinants of crash-related injury. This study aimed to determine the baseline frequency and distribution of transport injury and the prevalence of various road safety behaviours in a newly recruited cohort of Thai adults. Methods The Thai Health-Risk Transition Study includes an ongoing population-based cohort study of 87,134 adult students residing across Thailand. Baseline survey data from 2005 includes data on self-reported transport injury within the previous 12 months and demographic, behavioural and transportation factors that could be linked to Thailand's transport risks. Results Overall, 7279 (8.4% or 8354 per 100,000) of respondents reported that their most serious injury in the 12 months prior to recruitment in the cohort was transport-related, with risk being higher for males and those aged 15–19 years. Most transport injuries occurred while using motorcycles. A much higher proportion of males reported driving after three or more glasses of alcohol at least once in the previous year compared to females. The prevalence of motorcycle helmet and seat belt wearing in this sample were higher than previously reported for Thailand. Conclusions The reported data provide the basis for monitoring changes in traffic crash risks and risk behaviours in a cohort of adults in the context of ongoing implementation of policy and programs that are currently being introduced to address the problem of transport-related injury in Thailand. PMID:21376902

  6. Cross-lagged relations among parenting, children's emotion regulation, and psychosocial adjustment in early adolescence.

    PubMed

    Otterpohl, Nantje; Wild, Elke

    2015-01-01

    Numerous studies have reported substantive correlations between indicators of parenting, children's emotion regulation (ER), and children's psychosocial adjustment. However, studies on underlying mechanisms are scarce. Particularly in early adolescence, it is still unclear whether relations between parenting and ER are caused by adolescent behavior, by parent behavior, or by reciprocal processes. Moreover, it is unclear whether ER can be seen as an antecedent or a consequence of psychosocial adjustment. The aim of this study was to examine predictive relations among parenting and adolescents' ER, and adolescents' ER and psychosocial adjustment, respectively. We collected longitudinal, multiple informant data at two measurement occasions (Grade 6, Grade 7). All told, 1,100 adolescents (10-14 years) and their parents filled out questionnaires assessing responsiveness and psychological control, adolescents' anger regulation, and adolescents' problem and prosocial behavior. Cross-lagged analyses revealed reciprocal effects between parenting, ER, and adjustment for the parent and boys', but not for the girls', report. Moreover, relations were different for adolescents with versus without clinically elevated symptoms of psychopathology. Our findings support the assumption that reciprocal relations between parenting, ER, and psychosocial adjustment are likely to persist until early adolescence. Nevertheless, the moderating role of gender and psychopathology should be taken into account. Possible reasons for the different findings, and practical implications, are discussed. PMID:24320075

  7. Review of Cross-Cultural Issues Related to Quality of Life After Spinal Cord Injury

    PubMed Central

    Tate, Denise

    2014-01-01

    Quality of life (QOL) is a dynamic concept that means different things to different people, both in the general public and within the research community. Because of this, a common definition of QOL has been hard to achieve. This article reviews cross-cultural issues related to QOL research in spinal cord injury (SCI). Many factors influence QOL for persons with SCI, including observable and objective indicators and subjective self-report ones. The World Health Organization’s International Classification of Function, Disability and Health is used in this article as a framework to better understand how these factors may influence QOL. A number of important steps are summarized with respect to measurement issues in QOL. A comparison between data from 2 countries (United States and Brazil) using the International SCI QOL Basic Data Set shows similarities in scores and good reliability in the Brazilian sample. Substantial, significant correlations were observed among the SCI QOL Basic Data Set items and the WHOQOL-BREF within the US sample. The article ends with a set of recommendations for the development of cross-cultural measures of QOL for use in the SCI population. PMID:25484564

  8. Using optical tweezers to relate the chemical and mechanical cross-bridge cycles.

    PubMed Central

    Steffen, Walter; Sleep, John

    2004-01-01

    In most current models of muscle contraction there are two translational steps, the working stroke, whereby an attached myosin cross-bridge moves relative to the actin filament, and the repriming step, in which the cross-bridge returns to its original orientation. The development of single molecule methods has allowed a more detailed investigation of the relationship of these mechanical steps to the underlying biochemistry. In the normal adenosine triphosphate cycle, myosin.adenosine diphosphate.phosphate (M.ADP.Pi) binds to actin and moves it by ca. 5 nm on average before the formation of the end product, the rigor actomyosin state. All the other product-like intermediate states tested were found to give no net movement indicating that M.ADP.Pi alone binds in a pre-force state.Myosin states with bound, unhydrolysed nucleoside triphosphates also give no net movement, indicating that these must also bind in a post-force conformation and that the repriming, post- to pre-transition during the forward cycle must take place while the myosin is dissociated from actin. These observations fit in well with the structural model in which the working stroke is aligned to the opening of the switch 2 element of the ATPase site. PMID:15647161

  9. Immuno cross-reactivity suggests that catecholamine biosynthesis enzymes and beta adrenergic receptors may be related

    SciTech Connect

    Shorr, R.G.L.; Minnich, M.D.; Varrichio, A.; Strohsacker, M.W.; Gotlib, L.; Kruse, L.I.; DeWolf, W.E. Jr.; Crooke, S.T.

    1987-05-01

    Turkey red blood cell (RBC), Beta/sub 1/-adrenergic receptors (Bar) were prepared to electrophoretic homogeneity and denatured protein used to prepare rabbit anti-Bar antibodies. Anti-Bar activity was confirmed by immuno-adsorption of (/sup 125/I) cyanopindolol (CYP) labeled Bar. The catecholamine biosynthetic enzyme dopamine beta hydroxylase (DBH) was purified from bovine adrenal medullae chromaffin vesicles by ion exchange, size exclusion and concanavalin-A-Sepharose chromatography. Final DBH specific activities were 42 +/- 4 U/mg protein. Homogeneity was confirmed by non-denaturing PAGE. Bar was compared to DBH by anti-Bar antibody cross-reactivity. DBH and Bar were recognized by anti-Bar antibodies on immunoblotting. No interactions were observed with preimmune controls. Similar results were obtained with glycosylated and deglycosylated DBH suggesting that the antibodies recognize DBH amino acid sequence and not associated carbohydrate. Cross-reactive antibodies were purified by affinity chromatography using immobilized DBH and shown to immuno-adsorb (/sup 125/I)CYP labeled Bar. These results suggest that the catecholamine biosynthetic enzyme DBH and Bar may be related in structure.

  10. Environmental impact assessment in urban transport planning: Exploring process-related barriers in Spanish practice

    SciTech Connect

    Soria-Lara, Julio A. Bertolini, Luca Brömmelstroet, Marco te

    2015-01-15

    The effectiveness of EIA for evaluating transport planning projects is increasingly being questioned by practitioners, institutions and scholars. The academic literature has traditionally focused more on solving content-related problems with EIA (i.e. the measurement of environmental effects) than on process-related issues (i.e. the role of EIA in the planning process and the interaction between key actors). Focusing only on technical improvements is not sufficient for rectifying the effectiveness problems of EIA. In order to address this knowledge gap, the paper explores how EIA is experienced in the Spanish planning context and offers in-depth insight into EIA process-related issues in the field of urban transport planning. From the multitude of involved actors, the research focuses on exploring the perceptions of the two main professional groups: EIA developers and transport planners. Through a web-based survey we assess the importance of process-related barriers to the effective use of EIA in urban transport planning. The analyses revealed process issues based fundamentally on unstructured stakeholders involvement and an inefficient public participation - Highlights: • Qualitative research on perceptions of EIA participants on EIA processes. • Web-based survey with different participants (EIA-developers; transport planners). • It was seen an inefficient participation of stakeholders during the EIA processes.

  11. Axonal transport declines with age in two distinct phases separated by a period of relative stability☆

    PubMed Central

    Milde, Stefan; Adalbert, Robert; Elaman, M. Handan; Coleman, Michael P.

    2015-01-01

    Axonal transport is critical for supplying newly synthesized proteins, organelles, mRNAs, and other cargoes from neuronal cell bodies into axons. Its impairment in many neurodegenerative conditions appears likely to contribute to pathogenesis. Axonal transport also declines during normal aging, but little is known about the timing of these changes, or about the effect of aging on specific cargoes in individual axons. This is important for understanding mechanisms of age-related axon loss and age-related axonal disorders. Here we use fluorescence live imaging of peripheral nerve and central nervous system tissue explants to investigate vesicular and mitochondrial axonal transport. Interestingly, we identify 2 distinct periods of change, 1 period during young adulthood and the other in old age, separated by a relatively stable plateau during most of adult life. We also find that after tibial nerve regeneration, even in old animals, neurons are able to support higher transport rates of each cargo for a prolonged period. Thus, the age-related decline in axonal transport is not an inevitable consequence of either aging neurons or an aging systemic milieu. PMID:25443288

  12. Axonal transport declines with age in two distinct phases separated by a period of relative stability.

    PubMed

    Milde, Stefan; Adalbert, Robert; Elaman, M Handan; Coleman, Michael P

    2015-02-01

    Axonal transport is critical for supplying newly synthesized proteins, organelles, mRNAs, and other cargoes from neuronal cell bodies into axons. Its impairment in many neurodegenerative conditions appears likely to contribute to pathogenesis. Axonal transport also declines during normal aging, but little is known about the timing of these changes, or about the effect of aging on specific cargoes in individual axons. This is important for understanding mechanisms of age-related axon loss and age-related axonal disorders. Here we use fluorescence live imaging of peripheral nerve and central nervous system tissue explants to investigate vesicular and mitochondrial axonal transport. Interestingly, we identify 2 distinct periods of change, 1 period during young adulthood and the other in old age, separated by a relatively stable plateau during most of adult life. We also find that after tibial nerve regeneration, even in old animals, neurons are able to support higher transport rates of each cargo for a prolonged period. Thus, the age-related decline in axonal transport is not an inevitable consequence of either aging neurons or an aging systemic milieu. PMID:25443288

  13. Phonon-engineered thermal transport in Si wires with constant and periodically modulated cross-sections: A crossover between nano- and microscale regimes

    NASA Astrophysics Data System (ADS)

    Cocemasov, A. I.; Nika, D. L.; Fomin, V. M.; Grimm, D.; Schmidt, O. G.

    2015-07-01

    The transition between nanoscale and microscale thermal transport regime at room temperature in silicon wires with constant and periodically modulated cross-section is theoretically investigated. Extrapolating the calculated thermal conductivity from the nano- to micrometer range, we find the characteristic dimensions of the wires where a crossover between nanoscale and microscale thermal transport occurs. This crossover is observed in both generic (smooth) and cross-section-modulated wires. In case of smooth silicon wires, we reveal a strong dependence of the crossing point position on the boundary roughness. For silicon wires with weak boundary roughness, the crossover occurs at cross-sections ˜60 nm × 300 nm, while for very rough boundaries it occurs at cross-sections ˜150 nm × 750 nm. In case of the periodically modulated wires, the crossover between nano- and microscale regimes occurs at typical cross-sections ˜120 nm × 120 nm of the narrow segment, and it is almost independent of boundary roughness. A strong distinction from the case of smooth wires is attributed (i) to the different trends at the nanometer scale, wherefrom the extrapolation was performed, and (ii) to the different phonon-boundary scattering due to the specific geometry. For modulated silicon wires, the influence of modulation thickness, modulation length, and cross-sectional area on the phonon thermal conductivity at the room temperature is analyzed. A possibility of thermal transport engineering in cross-section-modulated wires by resizing them is revealed in both nano- and microscale regimes. The presented results pave the way towards a better understanding of thermal transport reduction in Si nanowires with engineered diameter modulations and shed light on the crossover between nano- and microscale regimes of thermal transport.

  14. Age-related alterations in the diffusional transport of amino acids across the human Bruch's-choroid complex

    NASA Astrophysics Data System (ADS)

    Hussain, Ali A.; Rowe, Lisa; Marshall, John

    2002-01-01

    Photoreceptor maintenance is dependent on effective delivery of nutrients from the choroidal circulation by way of the acellular Bruch's membrane and the retinal pigment epithelium. Aging of Bruch's membrane is associated with thickening, increased cross linking of fibers, and deposition of debris culminating in reduced porosity. The present study has investigated the effects of aging on the diffusional transport of eight amino acids across Bruch's membrane in 19 human donors. Diffusion studies were carried out in Ussing chambers, and the amount of time-dependent transfer of amino acids across the preparation was quantified by reverse-phase high-performance liquid chromatography. Diffusion rates for all amino acids showed a significant linear decline with aging of donor. The importance of this reduction in delivery of amino acids is discussed with reference to both normal physiology and age-related macular degeneration.

  15. Inhibition of nucleoside transport by a new series of compounds related to lidoflazine and mioflazine.

    PubMed

    Ijzerman, A P; Thedinga, K H; Custers, A F; Hoos, B; Van Belle, H

    1989-08-15

    A new series of compounds related to the nucleoside transport inhibitors, lidoflazine and mioflazine, is introduced. The influence of these derivatives on nucleoside-specific transport proteins was studied in two ways. First, a rapid, non-radioactive assay was developed for the screening of this type of material for actual transport inhibition in human erythrocytes. The method is based on the dose-dependent reversal of the inhibition of inorganic phosphate release induced by inosine when human erythrocytes are suspended in a phosphate-free medium. It enables the estimation of the potency and specificity of this new series of nucleoside transport inhibitors, most of which are highly active (EC50 values as low as 13 nM). Second, the displacement of a radiolabeled transport inhibitor, [3H]nitrobenzylthioinosine, was examined. All compounds were capable of displacing specific [3H]nitrobenzylthioinosine binding to crude and solubilized plasma membranes of calf lung tissue, displaying affinities in the nanomolar range. Pseudo-Hill coefficients derived from the shape of the displacement curves were significantly greater than unity for most derivatives, in contrast to values of approximately unity obtained for dipyridamole and analogs. These findings were incorporated in a mathematical model describing the interaction of mioflazine analogs with the transport protein, suggesting that one molecule of mioflazine is capable of displacing two or more molecules of [3H]nitrobenzylthioinosine at a time. The consequences of this model regarding the nature of the transport protein are discussed. PMID:2776845

  16. Robust transport by multiple motors with nonlinear force–velocity relations and stochastic load sharing

    PubMed Central

    Kunwar, Ambarish; Mogilner, Alexander

    2010-01-01

    Transport by processive molecular motors plays an important role in many cell biological phenomena. In many cases, motors work together to transport cargos in the cell, so it is important to understand the mechanics of the multiple motors. Based on earlier modeling efforts, here we study effects of nonlinear force–velocity relations and stochastic load sharing on multiple motor transport. We find that when two or three motors transport the cargo, then the nonlinear and stochastic effects compensate so that the mechanical properties of the transport are robust. Similarly, the transport is insensitive to compliance of the cargo-motor links. Furthermore, the rate of movement against moderate loads is not improved by increasing the small number of motors. When the motor number is greater than 4, correlations between the motors become negligible, and the earlier analytical mean-field theory of the multiple motor transport holds. We predict that the effective diffusion of the cargo driven by the multiple motors under load increases by an order of magnitude compared to that for the single motor. Finally, our simulations predict that the stochastic effects are responsible for a significant dispersion of velocities generated by the ‘tug-of-war’ of the multiple opposing motors. PMID:20147778

  17. Robust transport by multiple motors with nonlinear force-velocity relations and stochastic load sharing

    NASA Astrophysics Data System (ADS)

    Kunwar, Ambarish; Mogilner, Alexander

    2010-03-01

    Transport by processive molecular motors plays an important role in many cell biological phenomena. In many cases, motors work together to transport cargos in the cell, so it is important to understand the mechanics of the multiple motors. Based on earlier modeling efforts, here we study effects of nonlinear force-velocity relations and stochastic load sharing on multiple motor transport. We find that when two or three motors transport the cargo, then the nonlinear and stochastic effects compensate so that the mechanical properties of the transport are robust. Similarly, the transport is insensitive to compliance of the cargo-motor links. Furthermore, the rate of movement against moderate loads is not improved by increasing the small number of motors. When the motor number is greater than 4, correlations between the motors become negligible, and the earlier analytical mean-field theory of the multiple motor transport holds. We predict that the effective diffusion of the cargo driven by the multiple motors under load increases by an order of magnitude compared to that for the single motor. Finally, our simulations predict that the stochastic effects are responsible for a significant dispersion of velocities generated by the 'tug-of-war' of the multiple opposing motors.

  18. Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Brebrick, R. F.; Burger, A.; Dudley, M.; Ramachandran, N.

    2003-01-01

    The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows. ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, were grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals were characterized extensively to correlate the grown crystal properties with the growth conditions.

  19. Interactions between energy supply and transportation-related energy use, volume 1

    NASA Astrophysics Data System (ADS)

    Adler, T. J.; Ison, J. W.; Geinzer, J. C.

    1980-01-01

    The structure of ENTRANS and some of its policy analysis applications are described. ENTRANS is a computer simulator model of the interactions between energy supply and transportation related energy use. It includes a complete representation of the characteristics of transportation supply (public transit, carpooling, highways, and autos) and of households' travel related decisions (car type, travel mode, trip length, and frequency choices). The model is capable of analyzing a wide range of policies designed to change automobile fuel use. The results of several detailed policy analyses are described.

  20. Examination of the fundamental relation between ionic transport and segmental relaxation in polymer electrolytes

    SciTech Connect

    Wang, Yangyang; Fan, Fei; Agapov, Alexander L; Saito, Tomonori; Yang, Jun; Yu, Xiang; Hong, Kunlun; Mays, Jimmy; Sokolov, Alexei P

    2014-01-01

    Replacing traditional liquid electrolytes by polymers will significantly improve electrical energy storage technologies. Despite significant advantages for applications in electrochemical devices, the use of solid polymer electrolytes is strongly limited by their poor ionic conductivity. The classical theory predicts that the ionic transport is dictated by the segmental motion of the polymer matrix. As a result, the low mobility of polymer segments is often regarded as the limiting factor for development of polymers with sufficiently high ionic conductivity. Here, we show that the ionic conductivity in many polymers can be strongly decoupled from their segmental dynamics, in terms of both temperature dependence and relative transport rate. Based on this principle, we developed several polymers with superionic conductivity. The observed fast ion transport suggests a fundamental difference between the ionic transport mechanisms in polymers and small molecules and provides a new paradigm for design of highly conductive polymer electrolytes.

  1. Judgements of relative noisiness of a supersonic transport and several commercial-service aircraft

    NASA Technical Reports Server (NTRS)

    Powell, C. A.

    1977-01-01

    Two laboratory experiments were conducted on the relative noisiness of takeoff and landing operations of a supersonic transport and several other aircraft in current commercial service. A total of 96 subjects made noisiness judgments on 120 tape-recorded flyover noises in the outdoor-acoustic-simulation experiment; 32 different subjects made judgments on the noises in the indoor-acoustic-simulation experiment. The judgments were made by using the method of numerical category scaling. The effective perceived noise level underestimated the noisiness of the supersonic transport by 3.5 db. For takeoff operations, no difference was found between the noisiness of the supersonic transport and the group of other aircraft for the A-weighted rating scale; however, for landing operations, the noisiness of the supersonic transport was overestimated by 3.7 db. Very high correlation was found between the outdoor-simulation experiment and the indoor-simulation experiment.

  2. Street-Crossing Decision-Making: A Comparison between Patients with Age-Related Macular Degeneration and Normal Vision

    PubMed Central

    Hassan, Shirin E.; Snyder, Benjamin D.

    2012-01-01

    Purpose. We determined whether the street-crossing decisions of subjects with age-related macular degeneration (AMD) were as accurate and precise as those made by young and older subjects with normal vision. Methods. Street-crossing decisions in 13 AMD subjects, and 20 young and 20 older control subjects with normal vision were measured along an un-signalized street for nine different gap times. After calculating the discriminability (d') of the street-crossing decision variable for all gap pairs and entering these d' values into a one-dimensional scaling model, the means of each distribution of the decision variable relative to a “center of gravity” were estimated and plotted against gap time. The resultant plot was a nonlinear function. Street-crossing decision accuracy was computed for each subject as the difference between the x-intercept of the nonlinear function (tCOG) and subjects' measured street-crossing time. Street-crossing decision-making precision was computed as the value of the slope of the nonlinear function at tCOG. Results. We found that all subjects were precise in their street-crossing decisions (P = 0.55). Significant differences in street-crossing accuracy were found as a function of age (P = 0.003). Compared to either the older normally-sighted (P = 0.018) or AMD (P = 0.019) subjects, the young normally-sighted subjects made the least accurate street-crossing decisions. No significant difference in accuracy was found between the AMD and age-matched normally-sighted subjects (P = 0.90). Conclusions. Our data suggested that age and mild central vision loss did not affect significantly a subject's precision in their street-crossing decisions. Age, but not mild central vision loss, significantly affected a subject's accuracy in their street-crossing decisions. PMID:22899756

  3. Improving health-related fitness in adolescents: the CrossFit Teens™ randomised controlled trial.

    PubMed

    Eather, Narelle; Morgan, Philip James; Lubans, David Revalds

    2016-01-01

    The aim of this study was to evaluate the preliminary efficacy and feasibility of the CrossFit Teens™ resistance training programme for improving health-related fitness and resistance training skill competency in adolescents. This assessor-blinded randomised controlled trial was conducted in one secondary school in the Hunter Region, Australia, from July to September 2013. Ninety-six (96) students (age = 15.4 (.5) years, 51.5% female) were randomised into intervention (n = 51) or control (n = 45) conditions for 8-weeks (60 min twice per week). Waist circumference, body mass index (BMI), BMI-Z score (primary outcomes), cardiorespiratory fitness (shuttle run test), muscular fitness (standing jump, push-up, handgrip, curl-up test), flexibility (sit and reach) and resistance training skill competency were measured at baseline and immediate post-intervention. Feasibility measures of recruitment, retention, adherence and satisfaction were assessed. Significant group-by-time intervention effects were found for waist circumference [-3.1 cm, P < 0.001], BMI [-1.38 kg · m(‒)(2), P < 0.001], BMI-Z [-0.5 z-scores, P < 0.001], sit and reach [+3.0 cm, P < 0.001], standing jump [+0.1 m, P = 0.021] and shuttle run [+10.3 laps, P = 0.019]. Retention rate was 82.3%. All programme sessions were delivered and participants' mean satisfaction scores ranged from 4.2 to 4.6 out of 5. The findings demonstrate that CrossFit Teens™ is a feasible and efficacious programme for improving health-related fitness in adolescents. PMID:25972203

  4. Frequencies and Associations of Narcolepsy-Related Symptoms: A Cross-Sectional Study

    PubMed Central

    Kim, Lenise Jihe; Coelho, Fernando Morgadinho; Hirotsu, Camila; Araujo, Paula; Bittencourt, Lia; Tufik, Sergio; Andersen, Monica Levy

    2015-01-01

    Objectives: Narcolepsy is a disabling disease with a delayed diagnosis. At least 3 years before the disorder identification, several comorbidities can be observed in patients with narcolepsy. The early recognition of narcolepsy symptoms may improve long-term prognosis of the patients. Thus, we aimed to investigate the prevalence of the symptoms associated with narcolepsy and its social and psychological association in a sample of Sao Paulo city inhabitants. Methods: We performed a cross-sectional evaluation with 1,008 individuals from the Sao Paulo Epidemiologic Sleep Study (EPISONO). Excessive daytime sleepiness (EDS) was assessed by the Epworth Sleepiness Scale. Volunteers were also asked about the occurrence of cataplectic-like, hypnagogic or hypnopompic hallucinations, and sleep paralysis symptoms. The participants underwent a full-night polysomnography and completed questionnaires about psychological, demographic, and quality of life parameters. Results: We observed a prevalence of 39.2% of EDS, 15.0% of cataplectic-like symptom, 9.2% of hypnagogic or hypnopompic hallucinations, and 14.9% of sleep paralysis in Sao Paulo city inhabitants. A frequency of 6.9% was observed when EDS and cataplectic-like symptoms were grouped. The other associations were EDS + hallucinations (4.7%) and EDS + sleep paralysis (7.5%). Symptomatic participants were predominantly women and younger compared with patients without any narcolepsy symptom (n = 451). Narcolepsy symptomatology was also associated with a poor quality of life and symptoms of depression, anxiety, and fatigue. Conclusions: Narcolepsy-related symptoms are associated with poor quality of life and worse psychological parameters. Citation: Kim LJ, Coelho FM, Hirotsu C, Araujo P, Bittencourt L, Tufik S, Andersen ML. Frequencies and associations of narcolepsy-related symptoms: a cross-sectional study. J Clin Sleep Med 2015;11(12):1377–1384. PMID:26235160

  5. Cross-bedding Related Anisotropy and its Role in the Orientation of Joints in an Aeolian Sandstone

    NASA Astrophysics Data System (ADS)

    Deng, S.; Cilona, A.; Mapeli, C.; Panfilau, A.; Aydin, A.; Prasad, M.

    2014-12-01

    Previous research revealed that the cross-bedding related anisotropy in aeolian sandstones affects the orientation of compaction bands, also known as anticracks. We hypothesize that cross-bedding should a have similar influence on the orientation of the joints within the same rock at the same location. To test this hypothesis, we investigated the relationship between the cross-beds and the cross-bed package confined joints in the Jurassic aeolian Aztec Sandstone cropping out in the Valley of Fire State Park, Nevada. The field data demonstrates that the cross-bed package confined joints occur at high-angle to bedding and trend roughly parallel to the dip direction of the cross-beds. This shows that the cross-bed orientation and the associated anisotropy also exert a strong control on the formation and orientation of the joints. In order to characterize the anisotropy due to cross-bedding in the Aztec Sandstone, we measured the P-wave velocities parallel and perpendicular to bedding from 11 samples in the laboratory using a bench-top ultrasonic assembly. The measured P-wave anisotropy is about 13% on average. Based on these results, a numerical model based on the generalized Hooke's law for anisotropic materials is analyzed assuming the cross-bedded sandstone to be transversely isotropic. Using this model, we tested various cross-bed orientations as well as different strain boundary conditions (uniaxial, axisymmetric and triaxial). It is possible to define a boundary condition under which the modeled results roughly match with the observed relationship between cross-bed package confined joints and cross-beds. These results have important implications for fluid flow through aeolian sandstones in reservoirs and aquifers.

  6. Is Nurses' Professional Competence Related to Their Personality and Emotional Intelligence? A Cross-Sectional Study

    PubMed Central

    Heydari, Abbas; Kareshki, Hossein; Armat, Mohammad Reza

    2016-01-01

    Introduction: Nurses' professional competence is a crucial factor in clinical practice. Systematic evaluation of nurses’ competence and its related factors are essential for enhancing the quality of nursing care. This study aimed to assess the nurses’ competence level and its possible relationship with their personality and emotional intelligence. Methods: Using a cross-sectional survey design, three instruments including Nurse Competence Scale, short form of Schutte Self Report Emotional Intelligence Test, and the short 10-item version of Big Five Factor Inventory, were administered simultaneously to a randomized stratified sample of 220 nurses working in hospitals affiliated to Mashhad University of Medical Sciences. Data analysis was performed using SPSS 11.5. Results: Majority of nurses rated themselves as "good" and "very good", with the highest scores in "managing situations" and "work role" dimensions of nurse competence. A relatively similar pattern of scores was seen in competence dimensions, personality and emotional intelligence, among male and female nurses. Emotional intelligence and personality scores showed a significant relationship with nurses’ competence, explaining almost 20% of variations in nurse competence scores. Conclusion: Iranian nurses evaluated their overall professional competence at similar level of the nurses in other countries. Knowledge about the nurses’ competence level and its related factors, including personality and emotional intelligence, may help nurse managers in enhancing nurses' professional competence through appropriate task assignments and conducting in-service educational programs, thus improving the health status of patients. PMID:27354976

  7. An evolutionary attractor model for sapwood cross section in relation to leaf area.

    PubMed

    Westoby, Mark; Cornwell, William K; Falster, Daniel S

    2012-06-21

    Sapwood cross-sectional area per unit leaf area (SA:LA) is an influential trait that plants coordinate with physical environment and with other traits. We develop theory for SA:LA and also for root surface area per leaf area (RA:LA) on the premise that plants maximizing the surplus of revenue over costs should have competitive advantage. SA:LA is predicted to increase in water-relations environments that reduce photosynthetic revenue, including low soil water potential, high water vapor pressure deficit (VPD), and low atmospheric CO(2). Because sapwood has costs, SA:LA adjustment does not completely offset difficult water relations. Where sapwood costs are large, as in tall plants, optimal SA:LA may actually decline with (say) high VPD. Large soil-to-root resistance caps the benefits that can be obtained from increasing SA:LA. Where a plant can adjust water-absorbing surface area of root per leaf area (RA:LA) as well as SA:LA, optimal RA:SA is not affected by VPD, CO(2) or plant height. If selection favours increased height more so than increased revenue-minus-cost, then height is predicted to rise substantially under improved water-relations environments such as high-CO(2) atmospheres. Evolutionary-attractor theory for SA:LA and RA:LA complements models that take whole-plant conductivity per leaf area as a parameter. PMID:22763134

  8. Fano resonances in high energy electron transport in nanowires of variable cross-section

    NASA Astrophysics Data System (ADS)

    Baskin, L. M.; Kabardov, M. M.; Sharkova, N. M.

    2015-09-01

    Electron ballistic transport in 2D quantum waveguide with two narrowings is considered. For longitudinal electron motion such narrowings play the role of effective potential barriers and conditions for resonant tunneling arise. If the electron energy is sufficiently high the electron wave can scatter into different quantum states (transverse channels of the leads) which results in complicated E-dependence of the scattering amplitudes. Numerical simulations have shown that the scattering amplitudes resonances are of Fano type. The form of the transmission probability curve is conditioned by interference of the quantum states into which the electron wave is scattered by the narrowings. The suggested interference model makes possible to find the resonance parameters with high precision and to link them to the closed resonator eigenvalues.

  9. Are food-related perceptions associated with meal portion size decisions? A cross-sectional study.

    PubMed

    Spence, Michelle; Stancu, Violeta; Dean, Moira; Livingstone, M Barbara E; Gibney, Eileen R; Lähteenmäki, Liisa

    2016-08-01

    The purpose of this study was to test a comprehensive model of meal portion size determinants consisting of sociodemographic, psychological and food-related variables, whilst controlling for hunger and thirst. Using cross-sectional nationally representative data collected in 2075 participants from the Island of Ireland (IoI) and Denmark (DK), eight separate hierarchical multiple regression analyses were conducted to examine the association between food-related variables and meal portion size (i.e. pizza, vegetable soup, chicken salad and a pork meal) within each country. Stepwise regressions were run with physiological control measures (hunger and thirst) entered in the first step, sociodemographic variables (sex, age, body mass index (BMI)) in the second step; psychological variables (cognitive restraint, uncontrolled eating, emotional eating, general health interest (GHI)) in the third step and food-related variables (expected fillingness, liking, expected healthfulness, food familiarity) in the fourth step. Sociodemographic variables accounted for 2-19% of the variance in meal portion sizes; psychological variables explained an additional 3-8%; and food-related variables explained an additional 2-12%. When all four variable groups were included in the regression models, liking and sometimes expected healthfulness was positively associated with meal portion size. The strongest association was for liking, which was statistically significant in both countries for all meal types. Whilst expected healthfulness was not associated with pizza portion size in either country, it was positively associated with meals that have a healthier image (vegetable soup; chicken salad and in IoI, the pork meal). In conclusion, after considering sociodemographic and psychological variables, and the food-related variables of liking and expected healthfulness, there may be little merit in manipulating the satiating power, at least of these type of meals, to maintain or promote weight

  10. Subjective symptoms related to GSM radiation from mobile phone base stations: a cross-sectional study

    PubMed Central

    Gómez-Perretta, Claudio; Navarro, Enrique A; Segura, Jaume; Portolés, Manuel

    2013-01-01

    Objectives We performed a re-analysis of the data from Navarro et al (2003) in which health symptoms related to microwave exposure from mobile phone base stations (BSs) were explored, including data obtained in a retrospective inquiry about fear of exposure from BSs. Design Cross-sectional study. Setting La Ñora (Murcia), Spain. Participants Participants with known illness in 2003 were subsequently disregarded: 88 participants instead of 101 (in 2003) were analysed. Since weather circumstances can influence exposure, we restricted data to measurements made under similar weather conditions. Outcomes and methods A statistical method indifferent to the assumption of normality was employed: namely, binary logistic regression for modelling a binary response (eg, suffering fatigue (1) or not (0)), and so exposure was introduced as a predictor variable. This analysis was carried out on a regular basis and bootstrapping (95% percentile method) was used to provide more accurate CIs. Results The symptoms most related to exposure were lack of appetite (OR=1.58, 95% CI 1.23 to 2.03); lack of concentration (OR=1.54, 95% CI 1.25 to 1.89); irritability (OR=1.51, 95% CI 1.23 to 1.85); and trouble sleeping (OR=1.49, 95% CI 1.20 to 1.84). Changes in –2 log likelihood showed similar results. Concerns about the BSs were strongly related with trouble sleeping (OR =3.12, 95% CI 1.10 to 8.86). The exposure variable remained statistically significant in the multivariate analysis. The bootstrapped values were similar to asymptotic CIs. Conclusions This study confirms our preliminary results. We observed that the incidence of most of the symptoms was related to exposure levels—independently of the demographic variables and some possible risk factors. Concerns about adverse effects from exposure, despite being strongly related with sleep disturbances, do not influence the direct association between exposure and sleep. PMID:24381254