WorldWideScience

Sample records for angle distribution evolution

  1. Evolution of the jet opening angle distribution in holographic plasma

    CERN Document Server

    Rajagopal, Krishna; van der Schee, Wilke

    2016-01-01

    We use holography to analyze the evolution of an ensemble of jets, with an initial probability distribution for their energy and opening angle as %for jets in proton-proton (pp) collisions, as they propagate through an expanding cooling droplet of strongly coupled plasma as in heavy ion collisions. We identify two competing effects: (i) each individual jet widens as it propagates; (ii) the opening angle distribution for jets emerging from the plasma within any specified range of energies has been pushed toward smaller angles, comparing to pp jets with the same energies. The second effect arises because small-angle jets suffer less energy loss and because jets with a higher initial energy are less probable in the ensemble. We illustrate both effects in a simple two-parameter model, and find that their consequence in sum is that the opening angle distribution for jets in any range of energies contains fewer narrow and wide jets. Either effect can dominate in the mean opening angle, for not unreasonable values o...

  2. Evolution of the Jet Opening Angle Distribution in Holographic Plasma.

    Science.gov (United States)

    Rajagopal, Krishna; Sadofyev, Andrey V; van der Schee, Wilke

    2016-05-27

    We use holography to analyze the evolution of an ensemble of jets, with an initial probability distribution for their energy and opening angle as in proton-proton (pp) collisions, as they propagate through an expanding cooling droplet of strongly coupled plasma as in heavy ion collisions. We identify two competing effects: (i) each individual jet widens as it propagates and (ii) because wide-angle jets lose more energy, energy loss combined with the steeply falling perturbative spectrum serves to filter wide jets out of the ensemble at any given energy. Even though every jet widens, jets with a given energy can have a smaller mean opening angle after passage through the plasma than jets with that energy would have had in vacuum, as experimental data may indicate. PMID:27284647

  3. Evolution of electron pitch angle distributions across Saturn's middle magnetospheric region from MIMI/LEMMS

    Science.gov (United States)

    Clark, G.; Paranicas, C.; Santos-Costa, D.; Livi, S.; Krupp, N.; Mitchell, D. G.; Roussos, E.; Tseng, W.-L.

    2014-12-01

    We provide a global view of ~20 to 800 keV electron pitch angle distributions (PADs) close to Saturn's current sheet using observations from the Cassini MIMI/LEMMS instrument. Previous work indicated that the nature of pitch angle distributions in Saturn's inner to middle magnetosphere changes near the radial distance of 10RS. This work confirms the existence of a PAD transition region. Here we go further and develop a new technique to statistically quantify the spatial profile of butterfly PADs as well as present new spatial trends on the isotropic PAD. Additionally, we perform a case study analysis and show the PADs exhibit strong energy dependent features throughout this transition region. We also present a diffusion theory model based on adiabatic transport, Coulomb interactions with Saturn's neutral gas torus, and an energy dependent radial diffusion coefficient. A data-model comparison reveals that adiabatic transport is the dominant transport mechanism between ~8 to 12RS, however interactions with Saturn's neutral gas torus become dominant inside ~7RS and govern the flux level of ~20 to 800 keV electrons. We have also found that field-aligned fluxes were not well reproduced by our modeling approach. We suggest that wave-particle interactions and/or a polar source of the energetic particles needs further investigation.

  4. Evolution in opening angle combining DGLAP and BFKL logarithms

    OpenAIRE

    de Oliveira, E. G.; Martin, A. D.(Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE, Durham, UK); Ryskin, M. G.

    2014-01-01

    We present an evolution equation which simultaneously sums the leading BFKL and DGLAP logarithms for the integrated gluon distribution in terms of a single variable, namely the emission angle of the gluon. This form of evolution is appropriate for Monte Carlo simulations of events of high energy pp (and p\\bar{p}) interactions, particularly where small x events are sampled.

  5. Evolution in opening angle combining DGLAP and BFKL logarithms

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, E.G. de [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, C.P. 476, Florianopolis, SC (Brazil); Martin, A.D. [University of Durham, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Ryskin, M.G. [University of Durham, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, St. Petersburg (Russian Federation)

    2014-10-15

    We present an evolution equation which simultaneously sums the leading BFKL and DGLAP logarithms for the integrated gluon distribution in terms of a single variable, namely the emission angle of the gluon. This form of evolution is appropriate for Monte Carlo simulations of events of high energy pp (and p anti p) interactions, particularly where small x events are sampled. (orig.)

  6. Evolution of the plasma sheet electron pitch angle distribution by whistler-mode chorus waves in non-dipole magnetic fields

    Directory of Open Access Journals (Sweden)

    R. M. Thorne

    2012-04-01

    Full Text Available We present a detailed numerical study on the effects of a non-dipole magnetic field on the Earth's plasma sheet electron distribution and its implication for diffuse auroral precipitation. Use of the modified bounce-averaged Fokker-Planck equation developed in the companion paper by Ni et al. (2012 for 2-D non-dipole magnetic fields suggests that we can adopt a numerical scheme similar to that used for a dipole field, but should evaluate bounce-averaged diffusion coefficients and bounce period related terms in non-dipole magnetic fields. Focusing on nightside whistler-mode chorus waves at L = 6, and using various Dungey magnetic models, we calculate and compare of the bounce-averaged diffusion coefficients in each case. Using the Alternative Direction Implicit (ADI scheme to numerically solve the 2-D Fokker-Planck diffusion equation, we demonstrate that chorus driven resonant scattering causes plasma sheet electrons to be scattered much faster into loss cone in a non-dipole field than a dipole. The electrons subject to such scattering extends to lower energies and higher equatorial pitch angles when the southward interplanetary magnetic field (IMF increases in the Dungey magnetic model. Furthermore, we find that changes in the diffusion coefficients are the dominant factor responsible for variations in the modeled temporal evolution of plasma sheet electron distribution. Our study demonstrates that the effects of realistic ambient magnetic fields need to be incorporated into both the evaluation of resonant diffusion coefficients and the calculation of Fokker-Planck diffusion equation to understand quantitatively the evolution of plasma sheet electron distribution and the occurrence of diffuse aurora, in particular at L > 5 during geomagnetically disturbed periods when the ambient magnetic field considerably deviates from a magnetic dipole.

  7. Qualitative criterion for atom sputtering angle distributions

    International Nuclear Information System (INIS)

    A model is introduced to explain the shape of atom polar emission angle distributions for monocomponent targets sputtered by normally incident keV - energy ions. Analytical expressions are obtained from the model which make it possible to identify three known kinds of the angle distributions - subcosinus, isotropic and supracosinus, for given ion energies and target-ion pairs. Furthermore the fourth, hybrid false-isotropic distribution is found, which is superposition of supracosinus and subcosinus distributions. The theoretical predictions of the angle distributions shape agree with the numerical modeling for sputtering of carbon and platinum by 0.1-10 keV Ar+ ions

  8. Brownian Motion on a Sphere: Distribution of Solid Angles

    OpenAIRE

    Krishna, M. M. G.; Samuel, Joseph; Sinha, Supurna

    2000-01-01

    We study the diffusion of Brownian particles on the surface of a sphere and compute the distribution of solid angles enclosed by the diffusing particles. This function describes the distribution of geometric phases in two state quantum systems (or polarised light) undergoing random evolution. Our results are also relevant to recent experiments which observe the Brownian motion of molecules on curved surfaces like micelles and biological membranes. Our theoretical analysis agrees well with the...

  9. Solar proton event of April 16, 1970. 3. Evolution of pitch angle distribution as < or approx. =1-MeV protons propagate into the high-latitude magnetotail

    International Nuclear Information System (INIS)

    The solar proton event of April 16, 1970 was monitored by Vela satellites, of orbit r=18 R/sub E/, in the solar wind and high-latitude magnetotail (lobe). Intensity structure at < or approx. =1 MeV indicates a delay of 85--102 min in access of protons to near the center of the north lobe, corresponding to entry points at 340--370 R/sub E/ from the earth. In three sequential periods, of 16, 181, and 124 min duration, the average intensity in the north lobe was lower, higher, and lower, respectively, than that in interplanetary space, by factors which varied from 2 to 5. These reversals were a consequence of reversals in field-aligned anisotropy in interplanetary space, the interplanetary magnetic field remaining southward. Pitch angle distributions were measured in three dimensions in interplanetary space and in the north lobe. In the lobe the distributions were essentially isotropic at r=18 R/sub E/. Comparison is made with theoretical propagation of solar particles along field lines in an open tail model, under the following conditions along a trajectory: (1) adiabatic motion all the way (Liouville theorem) : the 'adiabatic access model' (2) isotropization at the magnetopause followed by adiabatic motion: the 'nonadiabatic access model'. Neither mode of access explains the observations adequately. A hybrid mode is proposed, in which a minimal amount of scattering occurs as particles enter the tail, followed by amplification (attenuation) of intensity as the pitch distribution is transformed to near 18 R/sub E/ in the favored (unfavored) lobe. In this mode a large part of the isotropization at Vela orbit is accomplished by the Liouville transformation, since particles entering the tail beyond approx. =100 R/sub E/ will see an increase in magnetic field by a factor of 3 as they propagate along the tail. The amount of scatter at the magnetopause is estimated to be Δμ (rms) =0.3, where μ is cosine of pitch angle

  10. Distribution of angles in hyperbolic lattices

    DEFF Research Database (Denmark)

    Risager, Morten Skarsholm; Truelsen, Jimi Lee

    2010-01-01

    We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result from the study by Boca.......We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result from the study by Boca....

  11. Distribution of Angles in Hyperbolic Lattices

    DEFF Research Database (Denmark)

    S. Risager, Morten; L. Truelsen, Jimi

    2008-01-01

    We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result due to F. P. Boca.......We prove an effective equidistribution result about angles in a hyperbolic lattice. We use this to generalize a result due to F. P. Boca....

  12. Contact pressure distribution and support angle optimization of kiln tyre

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

  13. Wide angle near-field diffraction and Wigner distribution

    CERN Document Server

    Almeida, J B

    2003-01-01

    Free-space propagation can be described as a shearing of the Wigner distribution function in the spatial coordinate; this shearing is linear in paraxial approximation but assumes a more complex shape for wide-angle propagation. Integration in the frequency domain allows the determination of near-field diffraction, leading to the well known Fresnel diffraction when small angles are considered and allowing exact prediction of wide-angle diffraction. The authors use this technique to demonstrate evanescent wave formation and diffraction elimination for very small apertures.

  14. Winding angle distributions for two-dimensional collapsing polymers

    Science.gov (United States)

    Narros, Arturo; Owczarek, Aleksander L.; Prellberg, Thomas

    2016-01-01

    We provide numerical support for a long-standing prediction of universal scaling of winding angle distributions. Simulations of interacting self-avoiding walks show that the winding angle distribution for N-step walks is compatible with the theoretical prediction of a Gaussian with a variance growing asymptotically as C log N, with C = 2 in the swollen phase (previously verified), and C = 24/7 at the θ-point. At low temperatures weaker evidence demonstrates compatibility with the same scaling and a value of C = 4 in the collapsed phase, also as theoretically predicted.

  15. Mathematical simulation of gamma-radiation angle distribution measurements

    International Nuclear Information System (INIS)

    We developed mathematical model of the facility for gamma-radiation angle distribution measurement and calculated response functions for gamma-radiation intensities. We developed special software for experimental data processing, the 'Shelter' object radiation spectra unfolding and Sphere detector (ShD) angle resolution estimation. Neuronet method using for detection of the radiation directions is given. We developed software based on the neuronet algorithm, that allows obtaining reliable distribution of gamma-sources that make impact on the facility detectors at the measurement point. 10 refs.; 15 figs.; 4 tab

  16. Effect of Air Outlet Angle on Air Distribution Performance Index

    Directory of Open Access Journals (Sweden)

    Isbeyeh W. Maid

    2013-05-01

    Full Text Available       In this paper a numerical study of velocity and temperature distribution in air conditioned space have been made. The computational model consists of the non-isothermal 3-D turbulent with (k-ε model. The numerical study is made to conduct air distribution in a room air-conditioned space with real interior dimensions (6×4×3m and to analyze the effect of changing angle of grille vanes on the flow pattern, velocity, and temperature distribution in the room under a set of different condition, and under a supply air temperature of 16˚C to examine the final result on air distribution performance index (ADPI.The results show a significant effect within the change of supply air angle, the maximum air distribution performance index (ADPI is 52% when air change per hour (ACH is equal to 10 at 16˚C inlet temperature with angle ( 15˚ down, and the minimum value of (ADPI is 20% when ACH is equal to 15 at 16˚C inlet temperature and angle ( degree. 

  17. BOND-ANGLE DISTRIBUTION FUNCTIONS IN METALLIC GLASSES

    OpenAIRE

    Hafner, J.

    1985-01-01

    Bond-angle distribution functions have been calculated for realistic models of metallic glasses. They suggest a defected icosahedral short-range bond-orientational order and a close analogy of the short-range topological order in the amorphous and in the crystalline states.

  18. SIMULATING THE EFFECTS OF INITIAL PITCH-ANGLE DISTRIBUTIONS ON SOLAR FLARES

    International Nuclear Information System (INIS)

    In this work, we model both the thermal and non-thermal components of solar flares. The model we use, HYLOOP, combines a hydrodynamic equation solver with a non-thermal particle tracking code to simulate the thermal and non-thermal dynamics and emission of solar flares. In order to test the effects of pitch-angle distribution on flare dynamics and emission, a series of flares is simulated with non-thermal electron beams injected at the loop apex. The pitch-angle distribution of each beam is described by a single parameter and allowed to vary from flare to flare. We use the results of these simulations to generate synthetic hard and soft X-ray emissions (HXR and SXR). The light curves of the flares in Hinode's X-ray Telescope passbands show a distinct signal that is highly dependent on pitch-angle distribution. The simulated HXR emission in the 3-6 keV bandpass shows the formation and evolution of emission sources that correspond well to the observations of pre-impulsive flares. This ability to test theoretical models of thermal and non-thermal flare dynamics directly with observations allows for the investigation of a wide range of physical processes governing the evolution of solar flares. We find that the initial pitch-angle distribution of non-thermal particle populations has a profound effect on loop top HXR and SXR emission and that apparent motion of HXR is a natural consequence of non-thermal particle evolution in a magnetic trap.

  19. Cultural Evolution as Distributed Computation

    OpenAIRE

    Gabora, Liane

    2013-01-01

    The speed and transformative power of human cultural evolution is evident from the change it has wrought on our planet. This chapter proposes a human computation program aimed at (1) distinguishing algorithmic from non-algorithmic components of cultural evolution, (2) computationally modeling the algorithmic components, and amassing human solutions to the non-algorithmic (generally, creative) components, and (3) combining them to develop human-machine hybrids with previously unforeseen comput...

  20. Evolution of dose distribution calculations in brachytherapy

    International Nuclear Information System (INIS)

    In this report the evolution of dose distribution calculations is revised in detail, considering the simplest case (a point source in free space) and the more complex situation of a real encapsulated line source embedded in a scattering medium. The most recent formalism to perform the dosimetry of interstitial brachytherapy sources is presented, where measured or measurable dose rates from actual sources in a tissue equivalent phantom are required as input data

  1. On World Religion Adherence Distribution Evolution

    OpenAIRE

    Ausloos, M.; Petroni, F.

    2008-01-01

    Religious adherence can be considered as a degree of freedom, in a statistical physics sense, for a human agent belonging to a population. The distribution, performance and life time of religions can thus be studied having in mind heterogeneous interacting agent modeling in mind. We present a comprehensive analysis of 58 so called religion (to be better defined in the main text) evolutions, as measured through their number of adherents between 1900 and 2000, - data taken from the World Christ...

  2. Small-angle x-ray scattering measurements of hydrogen evolution from an epitaxial Nb film

    International Nuclear Information System (INIS)

    Small-angle x-ray scattering (SAXS) measurements have been performed to investigate particle morphology during in situ hydrogen evolution from a 1000-A epitaxial Nb film on (112-bar0) sapphire initially loaded to saturation with hydrogen. The SAXS intensity follows the plate or disk single-particle form factor (Q-2, where Q is the wave-vector transfer) during hydrogen evolution. A fit to this power-law behavior yields a plate thickness of ≅7 A. A second power-law behavior (Q-3) was observed after complete hydrogen evolution. This power law corresponds to the small-angle scattering response from edge dislocations and is consistent with the broadening of the lattice mosaic induced by hydride decomposition

  3. Evolution of Quasar Spectral Energy Distributions

    Science.gov (United States)

    Schilling, Amanda; Kennefick, J.; Mahmood, A.

    2012-05-01

    A common practice when formulating quasar luminosity functions (QLF) has been to adopt an average spectral index, $\\alpha$, for the sample even though it is well known that quasars exhibit a broad range of spectral energy distributions (SED.) We have investigated the possible evolution of $\\alpha$ as a function of redshift, as any evolution in this parameter would introduce or mask evolution in the QLF. We imaged 103 Sloan Digital Sky Survey (SDSS) quasars in the optical and near-infrared bands, near in time to mitigate the effects of variability, in three redshift bins centered at $z\\approx 1.9$, $2.7$, and $4.0$, corresponding to look-back times of 10-12 billion years. We present restframe UV-optical SED’s and spectral indices and discuss possible evolution in our sample. We also use single epoch spectra of the quasars to estimate the mass of the central black hole and discuss possible correlations of quasar properties such as mass, luminosity, and spectral shape.

  4. Definition and Evolution of Transverse Momentum Distributions

    CERN Document Server

    Echevarria, Miguel G; Scimemi, Ignazio

    2012-01-01

    We consider the definition of unpolarized transverse-momentum-dependent parton distribution functions while staying on-the-light-cone. By imposing a requirement of identical treatment of two collinear sectors, our approach, compatible with a generic factorization theorem with the soft function included, is valid for all non-ultra-violet regulators (as it should), an issue which causes much confusion in the whole field. We explain how large logarithms can be resummed in a way which can be considered as an alternative to the use of Collins-Soper evolution equation. The evolution properties are also discussed and the gauge-invariance, in both classes of gauges, regular and singular, is emphasized.

  5. Small-angle X-ray scattering determination of the distribution of particle diameters in photochromic glasses

    International Nuclear Information System (INIS)

    The existing methods for determining particle size distributions from small angle X-ray scattering data are reviewed. The improved transform technique was used for calculating diameter distributions N(D) of lightsensitive silverhalide crystallites in photochromic glasses. From the evolution of N(D) during a certain heat treatment it can be concluded that two generations of crystallites of different size are precipitated. In glass I, the mean diameter D increases proportional to the time t of the treatment (reaction-limited growth) and in glass II D3 approximately t (diffusion-limited ripening) is obtained. (author)

  6. Solar proton pitch angle distribution for the January 24, 1969 event

    International Nuclear Information System (INIS)

    Pitch angle distributions during the highly anisotropic phase of the event are fitted by a polynomial in cosmic pitch angle, μ, and the results are compared with the predictions of a Fokker-Planck equation in μ space for quasi-steady injection. Implications for the theory of the diffusion coefficient D(μ) are discussed. (orig.)

  7. Characteristic function and Spitzer's law for the winding angle distribution of planar brownian curves

    International Nuclear Information System (INIS)

    Using the analogy between brownian motion and Quantum Mechanics, we study the winding angle θ of planar brownian curves around a given point, say the origin O. In particular, we compute the characteristic function for the probability distribution of θ and recover Spitzer's law in the limit of infinitely large times. Finally, we study the (large) change in the winding angle distribution when we add a repulsive potential at the origin

  8. Predicting dihedral angle probability distributions for protein coil residues from primary sequence using neural networks

    DEFF Research Database (Denmark)

    Helles, Glennie; Fonseca, Rasmus

    2009-01-01

    residue in the input-window. The trained neural network shows a significant improvement (4-68%) in predicting the most probable bin (covering a 30°×30° area of the dihedral angle space) for all amino acids in the data set compared to first order statistics. An accuracy comparable to that of secondary...... local context dependent dihedral angle propensities in coil-regions. This predicted distribution can potentially improve tertiary structure prediction methods that are based on sampling the backbone dihedral angles of individual amino acids. The predicted distribution may also help predict local...

  9. Influence of blade angle distribution along leading edge on cavitation performance of a centrifugal pump

    Science.gov (United States)

    Xu, Y.; Tan, L.; Cao, S. L.; Wang, Y. C.; Meng, G.; Qu, W. S.

    2015-01-01

    The influence of blade angle distribution along leading edge on cavitation performance of centrifugal pumps is analysed in the present paper. Three sets of blade angle distribution along leading edge for three blade inlet angles are chosen to design nine centrifugal pump impellers. The RNG k-epsilon turbulence model and the Zwart-Gerber-Belamri cavitation model are employed to simulate the cavitation flows in centrifugal pumps with different impellers and the same volute. The numerical results are compared with the experimental data, and the comparison proves that the numerical simulation can accurately predict the cavitation performance of centrifugal pumps. On the basis of the numerical simulations, the pump head variations with pump inlet pressure, and the flow details in centrifugal pump are revealed to demonstrate the influence of blade angle distribution along leading edge on cavitation performances of centrifugal pumps.

  10. Controls on stream network branching angles, tested using landscape evolution models

    Science.gov (United States)

    Theodoratos, Nikolaos; Seybold, Hansjörg; Kirchner, James W.

    2016-04-01

    Stream networks are striking landscape features. The topology of stream networks has been extensively studied, but their geometry has received limited attention. Analyses of nearly 1 million stream junctions across the contiguous United States [1] have revealed that stream branching angles vary systematically with climate and topographic gradients at continental scale. Stream networks in areas with wet climates and gentle slopes tend to have wider branching angles than in areas with dry climates or steep slopes, but the mechanistic linkages underlying these empirical correlations remain unclear. Under different climatic and topographic conditions different runoff generation mechanisms and, consequently, transport processes are dominant. Models [2] and experiments [3] have shown that the relative strength of channel incision versus diffusive hillslope transport controls the spacing between valleys, an important geometric property of stream networks. We used landscape evolution models (LEMs) to test whether similar factors control network branching angles as well. We simulated stream networks using a wide range of hillslope diffusion and channel incision parameters. The resulting branching angles vary systematically with the parameters, but by much less than the regional variability in real-world stream networks. Our results suggest that the competition between hillslope and channeling processes influences branching angles, but that other mechanisms may also be needed to account for the variability in branching angles observed in the field. References: [1] H. Seybold, D. H. Rothman, and J. W. Kirchner, 2015, Climate's watermark in the geometry of river networks, Submitted manuscript. [2] J. T. Perron, W. E. Dietrich, and J. W. Kirchner, 2008, Controls on the spacing of first-order valleys, Journal of Geophysical Research, 113, F04016. [3] K. E. Sweeney, J. J. Roering, and C. Ellis, 2015, Experimental evidence for hillslope control of landscape scale, Science, 349

  11. Simulations of Seasonal and Latitudinal Variations in Leaf Inclination Angle Distribution: Implications for Remote Sensing

    Science.gov (United States)

    Huemmrich, Karl F.

    2013-01-01

    The leaf inclination angle distribution (LAD) is an important characteristic of vegetation canopy structure affecting light interception within the canopy. However, LADs are difficult and time consuming to measure. To examine possible global patterns of LAD and their implications in remote sensing, a model was developed to predict leaf angles within canopies. Canopies were simulated using the SAIL radiative transfer model combined with a simple photosynthesis model. This model calculated leaf inclination angles for horizontal layers of leaves within the canopy by choosing the leaf inclination angle that maximized production over a day in each layer. LADs were calculated for five latitude bands for spring and summer solar declinations. Three distinct LAD types emerged: tropical, boreal, and an intermediate temperate distribution. In tropical LAD, the upper layers have a leaf angle around 35 with the lower layers having horizontal inclination angles. While the boreal LAD has vertical leaf inclination angles throughout the canopy. The latitude bands where each LAD type occurred changed with the seasons. The different LADs affected the fraction of absorbed photosynthetically active radiation (fAPAR) and Normalized Difference Vegetation Index (NDVI) with similar relationships between fAPAR and leaf area index (LAI), but different relationships between NDVI and LAI for the different LAD types. These differences resulted in significantly different relationships between NDVI and fAPAR for each LAD type. Since leaf inclination angles affect light interception, variations in LAD also affect the estimation of leaf area based on transmittance of light or lidar returns.

  12. Multi-angle Spectra Evolution of Langmuir Turbulence Excited by RF Ionospheric Interactions at HAARP

    Science.gov (United States)

    Sheerin, J. P.; Rayyan, N.; Watkins, B. J.; Bristow, W. A.; Spaleta, J.; Watanabe, N.; Golkowski, M.; Bernhardt, P. A.

    2013-12-01

    The high power HAARP HF transmitter is employed to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. Diagnostics included the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, and HF receivers to record stimulated electromagnetic emissions (SEE). Dependence of diagnostic signals on HAARP HF parameters, including pulselength, duty-cycle, aspect angle, and frequency were recorded. Short pulse, low duty cycle experiments demonstrate control of artificial field-aligned irregularities (AFAI) and isolation of ponderomotive effects. Among the effects observed and studied are: SLT spectra including cascade, collapse, and co-existence spectra and an outshifted plasma line under certain ionospheric conditions. High time resolution studies of the temporal evolution of the plasma line reveal the appearance of an overshoot effect on ponderomotive timescales. Bursty turbulence is observed in the collapse and cascade lines. For the first time, simultaneous multi-angle radar measurements of plasma line spectra are recorded demonstrating marked dependence on aspect angle with the strongest interaction region observed displaced southward of the HF zenith pointing angle. Numerous measurements of the outshifted plasma line are observed. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts.

  13. Multi-angle Spectra Evolution of Ionospheric Turbulence Excited by RF Interactions at HAARP

    Science.gov (United States)

    Sheerin, J. P.; Rayyan, N.; Watkins, B. J.; Watanabe, N.; Golkowski, M.; Bristow, W. A.; Bernhardt, P. A.; Briczinski, S. J., Jr.

    2014-12-01

    The high power HAARP HF transmitter is employed to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. Diagnostics included the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, and HF receivers to record stimulated electromagnetic emissions (SEE). Dependence of diagnostic signals on HAARP HF parameters, including pulselength, duty-cycle, aspect angle, and frequency were recorded. Short pulse, low duty cycle experiments demonstrate control of artificial field-aligned irregularities (AFAI) and isolation of ponderomotive effects. For the first time, simultaneous multi-angle radar measurements of plasma line spectra are recorded demonstrating marked dependence on aspect angle with the strongest interaction region observed displaced southward of the HF zenith pointing angle. For a narrow range of HF pointing between Spitze and magnetic zenith, a reduced threshold for AFAI is observed. High time resolution studies of the temporal evolution of the plasma line reveal the appearance of an overshoot effect on ponderomotive timescales. Numerous measurements of the outshifted plasma line are observed. Experimental results are compared to previous high latitude experiments and predictions from recent modeling efforts

  14. Pitch angle distribution measurements of an electron gun for electron transport experiments in stellarators

    International Nuclear Information System (INIS)

    The pitch angle distributions of a mesh type electron gun for the electron transport experiments in stellarators are estimated with the electron re-entry effect and the measurement method for pitch angle distribution by means of a local mirror field is proposed. It is found that the electron re-entry effect is significant to design electron guns for the electron transport experiment in stellarators because the high pitch angle electrons which re-enter into the gun launch again with a low pitch angle. The compensation method for an error field on the quasi helically symmetric stellarator HSX is also proposed. It is found that the additional toroidal mirror modes [n,m] = [3,0], [4,0] can eliminate a dangerous error field model [-1, -1] like the earth field. Here, n and m are toroidal and poloidal modes. (author)

  15. Optimal the tilt angles for photovoltaic modules using PSO method with nonlinear time-varying evolution

    International Nuclear Information System (INIS)

    A particle-swarm optimization method with nonlinear time-varying evolution (PSO-NTVE) is employed in determining the tilt angle of photovoltaic (PV) modules in Taiwan. The objective is to maximize the output electrical energy of the modules. In this study, seven Taiwanese cities were selected for analysis. First, the sun's position at any time and location was predicted by the mathematical procedure of Julian dating, and then the solar irradiation was obtained at each site under a clear sky. By combining the temperature effect, the PSO-NTVE method is adopted to calculate the optimal tilt angles for fixed south-facing PV modules. In this method, the parameters are determined by using matrix experiments with an orthogonal array, in which a minimal number of experiments have an effect that approximates the full factorial experiments. Statistical error analysis was performed to compare the results between the four PSO methods and experimental results. Hengchun city in which the minimum total error value of 6.12% the reasons for the weather more stability and less building shade. A comparison of the measurement results in electrical energy between the four PSO methods and the PV modules set a six tilt angles. Obviously four types of PSO methods simulation of electrical energy value from 231.12 kWh/m2 for Taipei to 233.81 kWh/m2 for Hengchun greater than the measurement values from 224.71 kWh/m2 for Taichung to 228.47 kWh/m2 for Hengchun by PV module which is due to instability caused by climate change. Finally, the results show that the annual optimal angle for the Taipei area is 18.16o; for Taichung, 17.3o; for Tainan, 16.15o; for Kaosiung, 15.79o; for Hengchung, 15.17o; for Hualian, 17.16o; and for Taitung, 15.94o. It is evident that the authorized Industrial Technology Research Institute (ITRI) recommends that tilt angle of 23.5o was not an appropriate use of Taiwan's seven cities. PV modules with the installation of the tilt angle should be adjusted in different

  16. Assessing protein conformational sampling methods based on bivariate lag-distributions of backbone angles

    KAUST Repository

    Maadooliat, Mehdi

    2012-08-27

    Despite considerable progress in the past decades, protein structure prediction remains one of the major unsolved problems in computational biology. Angular-sampling-based methods have been extensively studied recently due to their ability to capture the continuous conformational space of protein structures. The literature has focused on using a variety of parametric models of the sequential dependencies between angle pairs along the protein chains. In this article, we present a thorough review of angular-sampling-based methods by assessing three main questions: What is the best distribution type to model the protein angles? What is a reasonable number of components in a mixture model that should be considered to accurately parameterize the joint distribution of the angles? and What is the order of the local sequence-structure dependency that should be considered by a prediction method? We assess the model fits for different methods using bivariate lag-distributions of the dihedral/planar angles. Moreover, the main information across the lags can be extracted using a technique called Lag singular value decomposition (LagSVD), which considers the joint distribution of the dihedral/planar angles over different lags using a nonparametric approach and monitors the behavior of the lag-distribution of the angles using singular value decomposition. As a result, we developed graphical tools and numerical measurements to compare and evaluate the performance of different model fits. Furthermore, we developed a web-tool (http://www.stat.tamu. edu/~madoliat/LagSVD) that can be used to produce informative animations. © The Author 2012. Published by Oxford University Press.

  17. Spin-Orbit angle distribution and the origin of (mis)aligned hot Jupiters

    CERN Document Server

    Crida, Aurélien

    2014-01-01

    For 61 transiting hot Jupiters, the projection of the angle between the orbital plane and the stellar equator (called the spin-orbit angle) has been measured. For about half of them, a significant misalignment is detected, and retrograde planets have been observed. This challenges scenarios of the formation of hot Jupiters. In order to better constrain formation models, we relate the distribution of the real spin-orbit angle $\\Psi$ to the projected one $\\beta$. Then, a comparison with the observations is relevant. We analyse the geometry of the problem to link analytically the projected angle $\\beta$ to the real spin-orbit angle $\\Psi$. The distribution of $\\Psi$ expected in various models is taken from the literature, or derived with a simplified model and Monte-Carlo simulations in the case of the disk-torquing mechanism. An easy formula to compute the probability density function (PDF) of $\\beta$ knowing the PDF of $\\Psi$ is provided. All models tested here look compatible with the observed distribution be...

  18. Effect of Chorus Latitudinal Distribution on Evolution of Outer Radiation Belt Electrons

    Institute of Scientific and Technical Information of China (English)

    XIAO Fuliang; LI Junqiu; TANG Lijun; HE Yihua; LI Jiangfan

    2009-01-01

    Primary result on the impact of the latitudinal distribution of whistler-mode chorus upon temporal evolution of the phase space density (PSD) of outer radiation belt energetic electrons was presented.We evaluate diffusion rates in pitch angle and momentum due to a band of chorus frequency distributed at a standard Gaussian spectrum,and solve a 2-D bounce-averaged momentum-pitch-angle Fokker-Planck equation at L=4.5.It is shown that chorus is effective in accelerating electrons and can increase PSD for energy of ~1 MeV by a factor of 10 or more in about one day,which is consistent with observation.Moreover,the latitudinal distribution of chorus has a great impact on the acceleration of electrons.As the latitudinal distribution increases,the efficient acceleration region extends from higher pitch angles to lower pitch angles,and even covers the entire pitch angle region when chorus power reaches the maximum latitude λm=45°.

  19. Measurement of angle distribution in multiple scattering by track digitization method

    International Nuclear Information System (INIS)

    The multiple scattering of β-ray with neon gas atoms is studied by use of the projection spark chamber. The tracks are digitized and analysed on-line to give the projected angle distribution. The present data are compared with the Moliere theory. (author)

  20. Small-angle neutron scattering study of structural evolution of different phases in protein solution

    Indian Academy of Sciences (India)

    V K Aswal; S Chodankar; J Kohlbrecher; R Vavrin; A G Wagh

    2008-10-01

    Small-angle neutron scattering (SANS) has been used to study the structural evolution of different phases in protein solution leading to crystallization, denaturation and gelation. The protein solution under crystallization mostly consists of monomers and dimers, and higher-mers are not observed as they are perhaps formed in very small numbers. The onset and the rate of crystallization strongly depend on the salt concentration. Protein denaturation on addition of surfactant occurs due to the formation of micelle-like clusters along the unfolded polypeptide chains of the protein. The structure of such protein{surfactant complex is found to be independent of the size of the micelles in their pure surfactant solutions. The structure of temperature-induced protein gels shows a fractal structure. Rheology of these gels shows a strong dependence on varying pH or protein concentration, whereas the structure of such gels is found to be similar.

  1. Small-angle neutron scattering study of structural evolution of different phases in protein solution

    International Nuclear Information System (INIS)

    Small-angle neutron scattering (SANS) has been used to study the structural evolution of different phases in protein solution leading to crystallization, denaturation and gelation. The protein solution under crystallization mostly consists of monomers and dimmers, and higher-mers are not observed as they are perhaps formed in very small numbers. The onset and the rate of crystallization strongly depend on the salt concentration. Protein denaturation on addition of surfactant occurs due to the formation of micelle-like clusters along the unfolded polypeptide chains of the protein. The structure of such protein-surfactant complex is found to be independent of the size of the micelles in their pure surfactant solutions. The structure of temperature-induced protein gels shows a fractal structure. Rheology of these gels shows a strong dependence on varying pH or protein concentration, whereas the structure of such gels is found to be similar. (author)

  2. Evolution of surname distribution under gender-equality measurements

    OpenAIRE

    Lafuerza, Luis F.; Raul Toral

    2010-01-01

    We consider a model for the evolution of the surnames distribution under a gender-equality measurement presently discussed in the Spanish parliament (the children take the surname of the father or the mother according to alphabetical order). We quantify how this would bias the alphabetical distribution of surnames, and analyze its effect on the present distribution of the surnames in Spain.

  3. Evolution of the pulsar inclination angle in the wind braking model

    CERN Document Server

    Kou, F F; Wang, N

    2016-01-01

    In a plasma filled magnetosphere, in addition to providing a torque to brake down the pulsar, the magnetosphere will also generate a torque to align the pulsar magnetic and rotational axes. The evolution of pulsar inclination angle in the wind braking model is calculated. In the wind braking model, the oblique pulsar tends to align. The pulsar alignment will also affect the spin-down behavior. Braking index will increase firstly and then decrease as the pulsar evolving from the magneto-dipole radiation dominated case to the wind braking dominated case. Braking index may be larger than $3$ in the early time. And during the following long time, braking index will be always smaller than $3$. This can explain braking index observations of larger than $3$ and smaller than $3$. Besides, the pulsar will evolve downwards straightly to the death valley after pulsar death in the $P-\\dot{P}$ diagram. This may explain the observed maximum spinning period of pulsars. And the long-term evolution of pulsars in the wind brak...

  4. Evolution Equations for Higher Moments of Angular Momentum Distributions

    OpenAIRE

    Haegler, P.; Schaefer, A

    1998-01-01

    Based on a sumrule for the nucleon spin we expand quark and gluon orbital angular momentum operators and derive an evolution matrix for higher moments of the corresponding distributions. In combination with the spin-dependent DGLAP-matrix we find a complete set of spin and orbital angular momentum evolution equations.

  5. Correlations in double parton distributions. Effects of evolution

    International Nuclear Information System (INIS)

    We numerically investigate the impact of scale evolution on double parton distributions, which are needed to compute multiple hard scattering processes. Assuming correlations between longitudinal and transverse variables or between the parton spins to be present at a low scale, we study how they are affected by evolution to higher scales, i.e. by repeated parton emission. We find that generically evolution tends to wash out correlations, but with a speed that may be slow or fast depending on kinematics and on the type of correlation. Nontrivial parton correlations may hence persist in double parton distributions at the high scales relevant for hard scattering processes.

  6. Stress distributions in peri-miniscrew areas from cylindrical and tapered miniscrews inserted at different angles

    Science.gov (United States)

    Choi, Sung-Hwan; Kim, Seong-Jin; Lee, Kee-Joon; Sung, Sang-Jin; Chun, Youn-Sic

    2016-01-01

    Objective The purpose of this study was to analyze stress distributions in the roots, periodontal ligaments (PDLs), and bones around cylindrical and tapered miniscrews inserted at different angles using a finite element analysis. Methods We created a three-dimensional (3D) maxilla model of a dentition with extracted first premolars and used 2 types of miniscrews (tapered and cylindrical) with 1.45-mm diameters and 8-mm lengths. The miniscrews were inserted at 30°, 60°, and 90° angles with respect to the bone surface. A simulated horizontal orthodontic force of 2 N was applied to the miniscrew heads. Then, the stress distributions, magnitudes during miniscrew placement, and force applications were analyzed with a 3D finite element analysis. Results Stresses were primarily absorbed by cortical bone. Moreover, very little stress was transmitted to the roots, PDLs, and cancellous bone. During cylindrical miniscrew insertion, the maximum von Mises stress increased as insertion angle decreased. Tapered miniscrews exhibited greater maximum von Mises stress than cylindrical miniscrews. During force application, maximum von Mises stresses increased in both groups as insertion angles decreased. Conclusions For both cylindrical and tapered miniscrew designs, placement as perpendicular to the bone surface as possible is recommended to reduce stress in the surrounding bone. PMID:27478796

  7. Liquid-crystal variable-focus lenses with a spatially-distributed tilt angles.

    Science.gov (United States)

    Honma, Michinori; Nose, Toshiaki; Yanase, Satoshi; Yamaguchi, Rumiko; Sato, Susumu

    2009-06-22

    A pretilt angle controlling method by the density of rubbings using a tiny stylus is proposed. The control of the surface pretilt angle is achieved by rubbing a side-chain type polyimide film for a homeotropic alignment. Smooth liquid crystal (LC) director distribution in the bulk layer is successfully obtained even though the rough surface orientation. This approach is applied to LC cylindrical and rectangular lenses with a variable-focusing function. The distribution profile of the rubbing pitch (the reciprocal of the rubbing density) for small aberration is determined to be quadratic. The variable focusing function is successfully achieved in the LC rectangular lens, and the voltage dependence of the focal length is tried to be explained by the LC molecular reorientation behavior. PMID:19550499

  8. Prediction of optimum section pitch angle distribution along wind turbine blades

    International Nuclear Information System (INIS)

    Highlights: ► Prediction of optimum pitch angle along wind turbine blades. ► Maximum electrical power extraction at the installation site. ► Solving BEM equations with the probability distribution function of wind speed at a installation site. - Abstract: In this paper, the boost in electrical energy production of horizontal-axis wind turbines with fixed rotor speed is studied. To achieve this, a new innovative algorithm is proposed and justified to predict a distribution of section pitch angle along wind turbine blades that corresponds to the maximum power extraction in the installation site. A code is developed based on the blade element momentum theory which incorporates different corrections such as the tip loss correction. This aerodynamic code is capable of accurately predicting the aerodynamics of horizontal-axis wind turbines

  9. Microwave field distribution in a magic angle spinning dynamic nuclear polarization NMR probe

    OpenAIRE

    Nanni, Emilio A.; Barnes, Alexander B.; Matsuki, Yoh; Woskov, Paul P.; Corzilius, Björn; Griffin, Robert G.; Temkin, Richard J.

    2011-01-01

    We present a calculation of the microwave field distribution in a magic angle spinning (MAS) probe utilized in dynamic nuclear polarization (DNP) experiments. The microwave magnetic field (B[subscript 1S]) profile was obtained from simulations performed with the High Frequency Structure Simulator (HFSS) software suite, using a model that includes the launching antenna, the outer Kel-F stator housing coated with Ag, the RF coil, and the 4 mm diameter sapphire rotor containing the sample. The p...

  10. Pitch angle distributions of energetic ions in the lobes of the distant geomagnetic tail

    International Nuclear Information System (INIS)

    Analysis of energetic (> 35 keV) ion data from the ISEE-3 spacecraft obtained during 1982-1983, when the spacecraft made a series of traversals of the distant geomagnetic tail (XGSE > - 230 RE), indicates that the pitch angle distribution of energetic ions in the distant tail lobes is usually highly anisotropic, being peaked closely perpendicular to the magnetic field direction, but with a small net flow in the antisunward direction. In this paper we present a model, based on the motion of single particles into and within the tail lobes, which accounts for these observed distributions. This model assumes that the lobe ions originate in the magnetosheath, where the energetic ion population consists of two components; a spatially uniform ''solar'' population, and a population of ''terrestrial'' origin, which decreases in strength with downtail distance. The pitch angle distribution at any point within the lobe may be constructed, assuming that the value of the distribution function along the particle trajectory is conserved. In general, those ions with a large field-aligned component to their motion enter the lobes in the deep tail, where the ''terrestrial'' source is weak, whilst those moving closely perpendicular to the field enter the lobes at positions much closer to the Earth, where the source is strong. The fluxes of these latter ions are therefore much enhanced above the rest of the pitch angle distribution, and are shown to account for the form of the observed distributions. The model also accounts for the more isotropic ion population observed in the lobe during solar particle events, when the ''terrestrial'' component of the magnetosheath source may be considered negligible in comparison to the enhanced ''solar'' component. (author)

  11. Thickness distribution of multi-stage incremental forming with different forming stages and angle intervals

    Institute of Scientific and Technical Information of China (English)

    李军超; 杨芬芬; 周志强

    2015-01-01

    Although multi-stage incremental sheet forming has always been adopted instead of single-stage forming to form parts with a steep wall angle or to achieve a high forming performance, it is largely dependent on empirical designs. In order to research multi-stage forming further, the effect of forming stages (n) and angle interval between the two adjacent stages (Δα) on thickness distribution was investigated. Firstly, a finite element method (FEM) model of multi-stage incremental forming was established and experimentally verified. Then, based on the proposed simulation model, different strategies were adopted to form a frustum of cone with wall angle of 30° to research the thickness distribution of multi-pass forming. It is proved that the minimum thickness increases largely and the variance of sheet thickness decreases significantly as the value of n grows. Further, with the increase of Δα, the minimum thickness increases initially and then decreases, and the optimal thickness distribution is achieved with Δα of 10°. Additionally, a formula is deduced to estimate the sheet thickness after multi-stage forming and proved to be effective. And the simulation results fit well with the experimental results.

  12. Regge behaviour of distribution functions and and -evolutions of gluon distribution function at low-

    Indian Academy of Sciences (India)

    U Jamil; J K Sarma

    2007-08-01

    In this paper, and -evolutions of gluon distribution function from Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution equation in leading order (LO) at low- are presented assuming the Regge behaviour of quarks and gluons at this limit. We compare our results of gluon distribution function with MRST 2001, MRST 2004 and GRV 1998 parametrizations and show the compatibility of Regge behaviour of quark and gluon distribution functions with perturbative quantum chromodynamics (PQCD) at low-. We also discuss the limitations of Taylor series expansion method used earlier to solve DGLAP evolution equations in the Regge behaviour of distribution functions.

  13. Effect of rapid evolution of magnetic tilt angle on a newborn magnetar's dipole radiation

    International Nuclear Information System (INIS)

    We study the electromagnetic radiation from a newborn magnetar whose magnetic tilt angle decreases rapidly. We calculate the evolution of the angular spin frequency, the perpendicular component of the surface magnetic field strength, and the energy loss rate through magnetic dipole radiation. We show that the spin-down of the magnetar experiences two stages characterized by two different timescales. The apparent magnetic field decreases with the decrease of the tilt angle. We further show that the energy loss rate of the magnetar is very different from that in the case of a fixed tilt angle. The evolution of the energy loss rate is consistent with the overall light curves of gamma-ray bursts which show a plateau structure in their afterglow stage. Our model supports the idea that some gamma-ray bursts with a plateau phase in their afterglow stage may originate from newborn millisecond magnetars. (paper)

  14. Is the spherical leaf inclination angle distribution a valid assumption for temperate and boreal tree and shrub species?

    Science.gov (United States)

    Pisek, J.

    2012-12-01

    Directional distribution of leaves is one primary parameter for determining the radiation transmission through the canopy. When inverting canopy transmittance measurements for estimating the leaf area index or foliage clumping, incorrect assumptions on leaf angles may lead to considerable errors. Often spherical distribution of leaf normals is assumed, i.e. leaf normals are assumed to have no preferred direction in situations where no measurement data are available. The goal of this study is to examine if a spherical leaf angle distribution and the resulting isotropic G-function (G≡0.5) is indeed a valid assumption for temperate and boreal tree and shrub species. Leaf angle distributions were measured for over 80 deciduous broadleaf species commonly found in temperate and boreal ecoclimatic regions. The leaf inclination angles were obtained by sampling the complete vertical extent of trees and shrubs using a recently introduced technique based on digital photography. It is found a spherical leaf angle distribution is not a valid assumption for both tree and shrub species in temperate and boreal ecoclimatic regions. Given the influence of leaf angle distribution on inverting clumping and LAI estimates from canopy transmittance measurements, it is recommended to use planophile or plagiophile leaf angle distribution as more appropriate for modeling radiation transmission in temperate and boreal ecoclimatic regions when no actual leaf inclination angle measurements are available.

  15. ATLAS distributed computing: experience and evolution

    CERN Document Server

    Nairz, A; The ATLAS collaboration

    2014-01-01

    The ATLAS experiment has just concluded its first running period which commenced in 2010. After two years of remarkable performance from the LHC and ATLAS, the experiment has accumulated more than 25/fb of data. The total volume of beam and simulated data products exceeds 100~PB distributed across more than 150 computing centres around the world, managed by the experiment's distributed data management system. These sites have provided up to 150,000 computing cores to ATLAS's global production and analysis processing system, enabling a rich physics programme including the discovery of the Higgs-like boson in 2012. The wealth of accumulated experience in global data-intensive computing at this massive scale, and the considerably more challenging requirements of LHC computing from 2015 when the LHC resumes operation, are driving a comprehensive design and development cycle to prepare a revised computing model together with data processing and management systems able to meet the demands of higher trigger rates, e...

  16. ATLAS Distributed Computing: Experience and Evolution

    CERN Document Server

    Nairz, A; The ATLAS collaboration

    2013-01-01

    The ATLAS experiment has just concluded its first running period which commenced in 2010. After two years of remarkable performance from the LHC and ATLAS, the experiment has accumulated more than 25 fb-1 of data. The total volume of beam and simulated data products exceeds 100 PB distributed across more than 150 computing centers around the world, managed by the experiment's distributed data management system. These sites have provided up to 150,000 computing cores to ATLAS's global production and analysis processing system, enabling a rich physics program including the discovery of the Higgs-like boson in 2012. The wealth of accumulated experience in global data-intensive computing at this massive scale, and the considerably more challenging requirements of LHC computing from 2014 when the LHC resumes operation, are driving a comprehensive design and development cycle to prepare a revised computing model together with data processing and management systems able to meet the demands of higher trigger rates, e...

  17. Vesta Evolution from Surface Mineralogy: Mafic and Ultramafic Mineral Distribution

    Science.gov (United States)

    DeSanctis, M. C.; Ammannito, E.; Palomba, E.; Longobardo, A.; Mittlefehldt, D. W.; McSween, H. Y; Marchi, S.; Capria, M. T.; Capaccioni, F.; Frigeri, A.; Pieters, C. M.; Ruesch, O.; Tosi, F.; Zambon, F.; Hiesinger, H.; Magni, G.; McFadden, L. A.; Raymond, C. A.; Russell, C. T.; Sunshine, J. M.

    2014-01-01

    Vesta is the only intact, differentiated, rocky protoplanet and it is the parent body of HED meterorites. Howardite, eucrite and diogenite (HED) meteorites represent regolith, basaltic-crust, lower-crust and possibly ultramafic-mantle samples of asteroid Vesta. Only a few of these meteorites, the orthopyroxene-rich diogenites, contain olivine, a mineral that is a major component of the mantles of differentiated bodies, including Vesta. The HED parent body experienced complex igneous processes that are not yet fully understood and olivine and diogenite distribution is a key measurement to understand Vesta evolution. Here we report on the distribution of olivine and its constraints on vestan evolution models.

  18. Effect of slope angle of an artificial pool on distributions of turbulence

    Institute of Scientific and Technical Information of China (English)

    Atefeh Fazlollahi; Hossein Afzalimehr; Jueyi Sui

    2015-01-01

    abstract Experiments were carried out over a 2-dimentional pool with a constant length of 1.5 m and four different slopes. The distributions of velocity, Reynolds stress and turbulence intensities have been studied in this paper. Results show that as flow continues up the exit slope, the flow velocity increases near the channel bed and decreases near the water surface. The flow separation was not observed by ADV at the crest of the bed-form. In addition, the length of the separation zone increases with the increasing of entrance and exit slopes. The largest slope angle causes the maximum normalized shear stress. Based on the experiments, it is concluded that the shape of Reynolds stress distribution is generally dependent on the entrance and exit slopes of the pool. Also, the shape of Reynolds stress distribution is affected by both decelerating and accelerating flows. Additionally, with the increase in the slope angle, secondary currents are developed and become more stable. Results of the quadrant analysis show that the momentum between flow and bed-form is mostly transferred by sweep and ejection events.&2015 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved.

  19. The evolution of the magnetic inclination angle as an explanation of the long term red timing-noise of pulsars

    CERN Document Server

    Yi, Shu-Xu

    2015-01-01

    We study the possibility that the long term red timing-noise in pulsars originates from the evolution of the magnetic inclination angle $\\chi$. The braking torque under consideration is a combination of the dipole radiation and the current loss. We find that the evolution of $\\chi$ can give rise to extra cubic and fourth-order polynomial terms in the timing residuals. These two terms are determined by the efficiency of the dipole radiation, the relative electric-current density in the pulsar tube and $\\chi$. The following observation facts can be explained with this model: a) young pulsars have positive $\\ddot{\

  20. On the QCD evolution of transverse momentum dependent distributions

    International Nuclear Information System (INIS)

    We reconsider the evolution equations for transverse momentum dependent distributions recently proposed by us and recast them in a form which allows the comparison with results recently appeared in the literature. We show under which conditions the obtained results are consistent with each other

  1. Particle size distribution models of small angle neutron scattering pattern on ferro fluids

    International Nuclear Information System (INIS)

    The Fe3O4 ferro fluids samples were synthesized by a co-precipitation method. The investigation of ferro fluids microstructure is known to be one of the most important problems because the presence of aggregates and their internal structure influence greatly the properties of ferro fluids. The size and the size dispersion of particle in ferro fluids were determined assuming a log normal distribution of particle radius. The scattering pattern of the measurement by small angle neutron scattering were fitted by the theoretical scattering function of two limitation models are log normal sphere distribution and fractal aggregate. Two types of particle are detected, which are presumably primary particle of 30 Armstrong in radius and secondary fractal aggregate of 200 Armstrong with polydispersity of 0.47 up to 0.53. (author)

  2. Pitch angle distributions of electrons at dipolarization sites during geomagnetic activity: THEMIS observations

    Science.gov (United States)

    Wang, Kaiti; Lin, Ching-Huei; Wang, Lu-Yin; Hada, Tohru; Nishimura, Yukitoshi; Turner, Drew L.; Angelopoulos, Vassilis

    2014-12-01

    Changes in pitch angle distributions of electrons with energies from a few eV to 1 MeV at dipolarization sites in Earth's magnetotail are investigated statistically to determine the extent to which adiabatic acceleration may contribute to these changes. Forty-two dipolarization events from 2008 and 2009 observed by Time History of Events and Macroscale Interactions during Substorms probes covering the inner plasma sheet from 8 RE to 12 RE during geomagnetic activity identified by the AL index are analyzed. The number of observed events with cigar-type distributions (peaks at 0° and 180°) decreases sharply below 1 keV after dipolarization because in many of these events, electron distributions became more isotropized. From above 1 keV to a few tens of keV, however, the observed number of cigar-type events increases after dipolarization and the number of isotropic events decreases. These changes can be related to the ineffectiveness of Fermi acceleration below 1 keV (at those energies, dipolarization time becomes comparable to electron bounce time). Model-calculated pitch angle distributions after dipolarization with the effect of betatron and Fermi acceleration tested indicate that these adiabatic acceleration mechanisms can explain the observed patterns of event number changes over a large range of energies for cigar events and isotropic events. Other factors still need to be considered to assess the observed increase in cigar events around 2 keV. Indeed, preferential directional increase/loss of electron fluxes, which may contribute to the formation of cigar events, was observed. Nonadiabatic processes to accelerate electrons in a parallel direction may also be important for future study.

  3. Derivation of the Molière simultaneous distribution between the deflection angle and the lateral displacement

    Science.gov (United States)

    Okei, K.; Takahashi, N.; Nakatsuka, T.

    Moliere simultaneous distribution between the deflection angle and the lateral displacement is derived by applying numerical Fourier transforms on the solution for frequency distribution acquired through Kamata-Nishimura formulation of Moliere theory. The differences of our result from that under the gaussian approximation and the basic properties of our distribution are investigated closely.

  4. Nonlinear GLR-MQ evolution equation and Q{sup 2}-evolution of gluon distribution function

    Energy Technology Data Exchange (ETDEWEB)

    Devee, Mayuri; Sarma, J.K. [Tezpur University, HEP Laboratory, Department of Physics, Tezpur, Assam (India)

    2014-02-15

    In this paper we have solved the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for the gluon distribution function G(x, Q{sup 2}) and studied the effects of the nonlinear GLR-MQ corrections to the Leading Order (LO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations.Herewe have incorporated a Regge-like behavior of gluon distribution function to obtain the solution of the GLR-MQ evolution equation. We have also investigated the Q{sup 2}-dependence of the gluon distribution function from the solution of the GLRMQ evolution equation. Moreover it is interesting to observe from our results that nonlinearities increase with decreasing correlation radius (R) between two interacting gluons. The results also confirm that the steep behavior of gluon distribution function is observed at R = 5GeV{sup -1}, whereas it is lowered at R = 2GeV{sup -1} with decreasing x as Q{sup 2} increases. In this work we have also checked the sensitivity of λ{sub G} in our calculations. Our computed results are compared with those obtained by the global DGLAP fits to the parton distribution functions viz. GRV, MRST, MSTW and with the EHKQS model. (orig.)

  5. On the Evolution of Jet Energy and Opening Angle in Strongly Coupled Plasma

    CERN Document Server

    Chesler, Paul M

    2015-01-01

    We calculate how the energy and the opening angle of jets in ${\\cal N}=4$ SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss $dE_{\\rm jet}/dx$ and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for $dE_{\\rm jet}/dx$ without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say the opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that ${\\cal N}=4$ SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of t...

  6. A Neural Network Approach for Identifying Relativistic Electron Pitch Angle Distributions in Van Allen Probes Data

    Science.gov (United States)

    Souza, V. M. C. E. S.; Vieira, L.; Alves, L. R.; Da Silva, L. A.; Koga, D.; Sibeck, D. G.; Walsh, B.; Kanekal, S. G.; Silveira, M. D.; Medeiros, C.; Mendes, O., Jr.; Marchezi, J.; Rockenbach, M.; Jauer, P. R.; Gonzalez, W.; Baker, D. N.

    2015-12-01

    A myriad of physical phenomena occur in the inner magnetosphere, in particular at the Earth's radiation belts, which can be a result of the combination of both internal and external processes. However, the connection between physical processes occurring deep within the magnetosphere and external interplanetary drivers it is not yet well understood. In this work we investigate whether a selected set of interplanetary structures affect the local time distribution of three different classes of high energy electron pitch angle distributions (PADs), namely normal, isotropic, and butterfly. We split this work into two parts: initially we focus on the methodology used which employs a Self-Organized Feature Map (SOFM) neural network for identifying different classes of electron PAD shapes in the Van Allen Probes' Relativistic Electron Proton Telescope (REPT) data. The algorithm can categorize the input data into an arbitrary number of classes from which three of them appears the most: normal, isotropic and butterfly. Other classes which are related with these three also emerge and deserve to be addressed in detail in future works. We also discuss the uncertainties of the algorithm. Then, we move to the second part where we describe in details the criteria used for selecting the interplanetary events, and also try to investigate the relation between key parameters characterizing such interplanetary structures and the local time distributions of electron PAD shapes.

  7. Simultaneous measurement of deuterium distribution and impurities by emission angle analysis of deuteron induced reaction products

    CERN Document Server

    Kubota, N; Furuyama, Y; Kitamura, A

    2002-01-01

    A novel analytical method of light element distribution in a thin film is presented. The method is based on the deuteron-induced nuclear reaction. The emission angle of the lighter product detected coincidentally with the heavier product is analyzed to deduce the depth distribution of the target atoms, while the conventional energy analysis is applied for impurities, the distributions of which are not of primary interest. Results of proof-of-principle experiments using the D(d,p)t reaction for a deuterated polyethylene (C sub 2 D sub 4) film are described. The depth resolution is evaluated to be 0.66+-0.07 mu m for 400 keV deuteron incidence in the C sub 2 D sub 4 film. Factors limiting the resolution are discussed, and possible improvement even down to several tens of nm is concluded. The present method is applicable for microanalysis of some light elements other than deuterium contained in a film with thickness of several mu m which cannot be reached by conventional heavy ion elastic recoil detection using ...

  8. Proper definition and evolution of generalized transverse momentum distributions

    CERN Document Server

    Echevarria, Miguel G; Kanazawa, Koichi; Lorcé, Cédric; Metz, Andreas; Pasquini, Barbara; Schlegel, Marc

    2016-01-01

    We consider one of the most fundamental sets of hadronic matrix elements, namely the generalized transverse momentum distributions (GTMDs), and argue that their existing definitions lack proper evolution properties. By exploiting the similarity of GTMDs with the much better understood transverse momentum distributions, we argue that the existing definitions of GTMDs have to include an additional dependence on soft gluon radiation in order to render them properly defined. With this, we manage to obtain the evolution kernel of all (un)polarized quark and gluon GTMDs, which turns out to be spin independent. As a byproduct, all large logarithms can be resummed up to next-to-next-to-leading-logarithmic accuracy with the currently known perturbative ingredients.

  9. Proper definition and evolution of generalized transverse momentum dependent distributions

    Science.gov (United States)

    Echevarria, Miguel G.; Idilbi, Ahmad; Kanazawa, Koichi; Lorcé, Cédric; Metz, Andreas; Pasquini, Barbara; Schlegel, Marc

    2016-08-01

    We consider one of the most fundamental sets of hadronic matrix elements, namely the generalized transverse momentum dependent distributions (GTMDs), and argue that their existing definitions lack proper evolution properties. By exploiting the similarity of GTMDs with the much better understood transverse momentum distributions, we argue that the existing definitions of GTMDs have to include an additional dependence on soft gluon radiation in order to render them properly defined. With this, we manage to obtain the evolution kernel of all (un)polarized quark and gluon GTMDs, which turns out to be spin independent. As a byproduct, all large logarithms can be resummed up to next-to-next-to-leading-logarithmic accuracy with the currently known perturbative ingredients.

  10. Proper definition and evolution of generalized transverse momentum dependent distributions

    Directory of Open Access Journals (Sweden)

    Miguel G. Echevarria

    2016-08-01

    Full Text Available We consider one of the most fundamental sets of hadronic matrix elements, namely the generalized transverse momentum dependent distributions (GTMDs, and argue that their existing definitions lack proper evolution properties. By exploiting the similarity of GTMDs with the much better understood transverse momentum distributions, we argue that the existing definitions of GTMDs have to include an additional dependence on soft gluon radiation in order to render them properly defined. With this, we manage to obtain the evolution kernel of all (unpolarized quark and gluon GTMDs, which turns out to be spin independent. As a byproduct, all large logarithms can be resummed up to next-to-next-to-leading-logarithmic accuracy with the currently known perturbative ingredients.

  11. Seasonal and vertical changes in leaf angle distribution for selected deciduous broadleaf tree species common to Europe

    Science.gov (United States)

    Raabe, Kairi; Pisek, Jan; Sonnentag, Oliver; Annuk, Kalju

    2014-05-01

    Leaf inclination angle distribution is a key parameter in determining the transmission and reflection of radiation by vegetation canopies. It has been previously observed that leaf inclination angle might change gradually from more vertical in the upper canopy and in high light habitats to more horizontal in the lower canopy and in low light habitats [1]. Despite its importance, relatively few measurements on actual leaf angle distributions have been reported for different tree species. Even smaller number of studies have dealt with the possible seasonal changes in leaf angle distribution [2]. In this study the variation of leaf inclination angle distributions was examined both temporally throughout the growing season and vertically at different heights of trees. We report on leaf inclination angle distributions for five deciduous broadleaf species found commonly in several parts of Europe: grey alder (Alnus incana), Silver birch (Betula pendula Roth), chestnut (Castanea), Norway maple (Acer platanoides), and aspen (Populus tremula). The angles were measured using the leveled camera method [3], with the data collected at several separate heights and four times during the period of May-September 2013. The results generally indicate the greatest change in leaf inclination angles for spring, with the changes usually being the most pronounced at the top of the canopy. It should also be noted, however, that whereas the temporal variation proved to be rather consistent for different species, the vertical variation differed more between species. The leveled camera method was additionally tested in terms of sensitivity to different users. Ten people were asked to measure the leaf angles for four different species. The results indicate the method is quite robust in providing coinciding distributions irrespective of the user and level of previous experience with the method. However, certain caution must be exercised when measuring long narrow leaves. References [1] G.G. Mc

  12. Effects of Schroth and Pilates exercises on the Cobb angle and weight distribution of patients with scoliosis.

    Science.gov (United States)

    Kim, Gichul; HwangBo, Pil-Neo

    2016-03-01

    [Purpose] The purpose of this study was to compare the effect of Schroth and Pilates exercises on the Cobb angle and body weight distribution of patients with idiopathic scoliosis. [Subjects] Twenty-four scoliosis patients with a Cobb angle of ≥20° were divided into the Schroth exercise group (SEG, n = 12) and the Pilates exercise group (PEG, n = 12). [Methods] The SEG and PEG performed Schroth and Pilates exercises, respectively, three times a week for 12 weeks. The Cobb angle was measured in the standing position with a radiography apparatus, and weight load was measured with Gait View Pro 1.0. [Results] In the intragroup comparison, both groups showed significant changes in the Cobb angle. For weight distribution, the SEG showed significant differences in the total weight between the concave and convex sides, but the PEG did not show significant differences. Furthermore, in the intragroup comparison, the SEG showed significant differences in the changes in the Cobb angle and weight distribution compared with the PEG. [Conclusion] Both Schroth and Pilates exercises were effective in changing the Cobb angle and weight distribution of scoliosis patients; however, the intergroup comparison showed that the Schroth exercise was more effective than the Pilates exercise. PMID:27134403

  13. A neural network approach for identifying particle pitch angle distributions in Van Allen Probes data

    Science.gov (United States)

    Souza, V. M.; Vieira, L. E. A.; Medeiros, C.; Da Silva, L. A.; Alves, L. R.; Koga, D.; Sibeck, D. G.; Walsh, B. M.; Kanekal, S. G.; Jauer, P. R.; Rockenbach, M.; Dal Lago, A.; Silveira, M. V. D.; Marchezi, J. P.; Mendes, O.; Gonzalez, W. D.; Baker, D. N.

    2016-04-01

    Analysis of particle pitch angle distributions (PADs) has been used as a means to comprehend a multitude of different physical mechanisms that lead to flux variations in the Van Allen belts and also to particle precipitation into the upper atmosphere. In this work we developed a neural network-based data clustering methodology that automatically identifies distinct PAD types in an unsupervised way using particle flux data. One can promptly identify and locate three well-known PAD types in both time and radial distance, namely, 90° peaked, butterfly, and flattop distributions. In order to illustrate the applicability of our methodology, we used relativistic electron flux data from the whole month of November 2014, acquired from the Relativistic Electron-Proton Telescope instrument on board the Van Allen Probes, but it is emphasized that our approach can also be used with multiplatform spacecraft data. Our PAD classification results are in reasonably good agreement with those obtained by standard statistical fitting algorithms. The proposed methodology has a potential use for Van Allen belt's monitoring.

  14. Effects of Schroth and Pilates exercises on the Cobb angle and weight distribution of patients with scoliosis

    OpenAIRE

    Kim, Gichul; Hwangbo, Pil-Neo

    2016-01-01

    [Purpose] The purpose of this study was to compare the effect of Schroth and Pilates exercises on the Cobb angle and body weight distribution of patients with idiopathic scoliosis. [Subjects] Twenty-four scoliosis patients with a Cobb angle of ≥20° were divided into the Schroth exercise group (SEG, n = 12) and the Pilates exercise group (PEG, n = 12). [Methods] The SEG and PEG performed Schroth and Pilates exercises, respectively, three times a week for 12 weeks. The Cobb angle was measured i...

  15. Electron fluxes and pitch-angle distributions at dipolarization fronts: THEMIS multipoint observations

    Science.gov (United States)

    Runov, A.; Angelopoulos, V.; Gabrielse, C.; Zhou, X.-Z.; Turner, D.; Plaschke, F.

    2013-02-01

    Taking advantage of multipoint observations from a Cluster-like Time History of Events and Macroscale Interactions during Substorms (THEMIS) probe configuration repeated in three events, we study pitch-angle distributions (PAD) of lower energy (0.2-keV) electrons and omnidirectional energy-time spectrograms of higher energy (30-500 keV) electrons observed at and near dipolarization fronts in the plasma sheet. Recent observations have shown that dipolarization fronts in the plasma sheet provide an impulsive electric field suggested to cause electron energization and dispersionless injections. Increase and decrease in energetic electron flux are equally probable at the fronts, however. Our case studies demonstrate increased energetic electron flux in the front's central region but decreased flux on its dusk side, where diverted plasma flow forms a vortex. An electric field associated with this vortex causes the electron flux decrease. We also find that shorter-term energetic flux decreases, often observed before injections, coincide with a dip in the northward magnetic field ahead of the front. We attribute these decreases to particle energy loss via the inverse betatron effect. Our case studies reveal that pancake-type (maximum at 90° pitch angle) and cigar-type (maxima at 0 and 180°) PADs coexist at the same front. Our data analysis suggests that energetic electron PADs are mainly pancake type near the neutral sheet (|Bx| cigar type at |Bx| > 10 nt. These results, to be confirmed in statistical studies, provide important constraints for further modeling of electron energization and transport toward the inner magnetosphere.

  16. The evolution of gauge couplings and the Weinberg angle in 5 dimensions for an SU(3) gauge group

    CERN Document Server

    Khojali, Mohammed Omer; Deandrea, Aldo

    2016-01-01

    We test in a simplified 5-dimensional model with SU(3) gauge symmetry, the evolution equations of the gauge couplings of a model containing bulk fields, gauge fields and one pair of fermions. In this model we assume that the fermion doublet and two singlet fields are located at fixed points of the extra-dimension compactified on an $S^{1}/Z_{2}$ orbifold. The gauge coupling evolution is derived at one-loop in 5-dimensions, for the gauge group $G = SU(3)$, and used to test the impact on lower energy observables, in particular the Weinberg angle. The gauge bosons and the Higgs field arise from the gauge bosons in 5 dimensions, as in a gauge-Higgs model. The model is used as a testing ground as it is not a complete and realistic model for the electroweak interactions.

  17. Zenith angle distributions at Super-Kamiokande and SNO and the solution of the solar neutrino problem

    CERN Document Server

    González-Garciá, M Concepción; Smirnov, Yu A

    2001-01-01

    We have performed a detailed study of the zenith angle dependence of the regeneration factor and distributions of events at SNO and SK for different solutions of the solar neutrino problem. In particular, we discuss oscillatory behaviour and the synchronization effect in the distribution for the LMA solution, the parametric peak for the LOW solution, etc.. Physical interpretation of the effects is given. We suggest a new binning of events which emphasizes distinctive features of zenith angle distributions for the different solutions. We also find the correlations between the integrated day-night asymmetry and the rates of events in different zenith angle bins. Study of these correlations strengthens the identification power of the analysis.

  18. Intracranial cerebrospinal fluid spaces imaging using a pulse-triggered three-dimensional turbo spin echo MR sequence with variable flip-angle distribution

    International Nuclear Information System (INIS)

    To assess the three-dimensional turbo spin echo with variable flip-angle distribution magnetic resonance sequence (SPACE: Sampling Perfection with Application optimised Contrast using different flip-angle Evolution) for the imaging of intracranial cerebrospinal fluid (CSF) spaces. We prospectively investigated 18 healthy volunteers and 25 patients, 20 with communicating hydrocephalus (CH), five with non-communicating hydrocephalus (NCH), using the SPACE sequence at 1.5T. Volume rendering views of both intracranial and ventricular CSF were obtained for all patients and volunteers. The subarachnoid CSF distribution was qualitatively evaluated on volume rendering views using a four-point scale. The CSF volumes within total, ventricular and subarachnoid spaces were calculated as well as the ratio between ventricular and subarachnoid CSF volumes. Three different patterns of subarachnoid CSF distribution were observed. In healthy volunteers we found narrowed CSF spaces within the occipital aera. A diffuse narrowing of the subarachnoid CSF spaces was observed in patients with NCH whereas patients with CH exhibited narrowed CSF spaces within the high midline convexity. The ratios between ventricular and subarachnoid CSF volumes were significantly different among the volunteers, patients with CH and patients with NCH. The assessment of CSF spaces volume and distribution may help to characterise hydrocephalus. (orig.)

  19. Evolution of the Magnetic Field Distribution of Active Regions

    CERN Document Server

    Dacie, Sally; van Driel-Gesztelyi, Lidia; Long, David; Baker, Deb; Janvier, Miho; Yardley, Stephanie; Pérez-Suárez, David

    2016-01-01

    Aims. Although the temporal evolution of active regions (ARs) is relatively well understood, the processes involved continue to be the subject of investigation. We study how the magnetic field of a series of ARs evolves with time to better characterise how ARs emerge and disperse. Methods. We examine the temporal variation in the magnetic field distribution of 37 emerging ARs. A kernel density estimation plot of the field distribution was created on a log-log scale for each AR at each time step. We found that the central portion of the distribution is typically linear and its slope was used to characterise the evolution of the magnetic field. Results. The slopes were seen to evolve with time, becoming less steep as the fragmented emerging flux coalesces. The slopes reached a maximum value of ~ -1.5 just before the time of maximum flux before becoming steeper during the decay phase towards the quiet Sun value of ~ -3. This behaviour differs significantly from a classical diffusion model, which produces a slope...

  20. Using Hybrid Angle/Distance Information for Distributed Topology Control in Vehicular Sensor Networks

    Directory of Open Access Journals (Sweden)

    Chao-Chi Huang

    2014-10-01

    Full Text Available In a vehicular sensor network (VSN, the key design issue is how to organize vehicles effectively, such that the local network topology can be stabilized quickly. In this work, each vehicle with on-board sensors can be considered as a local controller associated with a group of communication members. In order to balance the load among the nodes and govern the local topology change, a group formation scheme using localized criteria is implemented. The proposed distributed topology control method focuses on reducing the rate of group member change and avoiding the unnecessary information exchange. Two major phases are sequentially applied to choose the group members of each vehicle using hybrid angle/distance information. The operation of Phase I is based on the concept of the cone-based method, which can select the desired vehicles quickly. Afterwards, the proposed time-slot method is further applied to stabilize the network topology. Given the network structure in Phase I, a routing scheme is presented in Phase II. The network behaviors are explored through simulation and analysis in a variety of scenarios. The results show that the proposed mechanism is a scalable and effective control framework for VSNs.

  1. Using hybrid angle/distance information for distributed topology control in vehicular sensor networks.

    Science.gov (United States)

    Huang, Chao-Chi; Chiu, Yang-Hung; Wen, Chih-Yu

    2014-01-01

    In a vehicular sensor network (VSN), the key design issue is how to organize vehicles effectively, such that the local network topology can be stabilized quickly. In this work, each vehicle with on-board sensors can be considered as a local controller associated with a group of communication members. In order to balance the load among the nodes and govern the local topology change, a group formation scheme using localized criteria is implemented. The proposed distributed topology control method focuses on reducing the rate of group member change and avoiding the unnecessary information exchange. Two major phases are sequentially applied to choose the group members of each vehicle using hybrid angle/distance information. The operation of Phase I is based on the concept of the cone-based method, which can select the desired vehicles quickly. Afterwards, the proposed time-slot method is further applied to stabilize the network topology. Given the network structure in Phase I, a routing scheme is presented in Phase II. The network behaviors are explored through simulation and analysis in a variety of scenarios. The results show that the proposed mechanism is a scalable and effective control framework for VSNs. PMID:25350506

  2. High-energy spectrum and zenith-angle distribution of atmospheric neutrinos

    CERN Document Server

    Sinegovsky, S I; Sinegovskaya, T S

    2011-01-01

    High-energy neutrinos, arising from decays of mesons produced through the collisions of cosmic ray particles with air nuclei, form the background in the astrophysical neutrino detection problem. An ambiguity in high-energy behavior of pion and especially kaon production cross sections for nucleon-nucleus collisions may affect essentially the calculated neutrino flux. We present results of the calculation of the energy spectrum and zenith-angle distribution of the muon and electron atmospheric neutrinos in the energy range 10 GeV to 10 PeV. The calculation was performed with usage of known hadronic models (QGSJET-II-03, SIBYLL 2.1, Kimel & Mokhov) for two of the primary spectrum parametrizations, by Gaisser & Honda and by Zatsepin & Sokolskaya. The comparison of the calculated muon neutrino spectrum with the IceCube40 experiment data make it clear that even at energies above 100 TeV the prompt neutrino contribution is not so apparent because of tangled uncertainties of the strange (kaons) and charm...

  3. Counterion Distribution Around Protein-SNAs probed by Small-angle X-ray scattering

    Science.gov (United States)

    Krishnamoorthy, Kurinji; Bedzyk, Michael; Kewalramani, Sumit; Moreau, Liane; Mirkin, Chad

    Protein-DNA conjugates couple the advanced cell transfection capabilities of spherical DNA architecture and the biocompatible enzymatic activity of a protein core to potentially create therapeutic agents with dual functionality. An understanding of their stabilizing ionic environment is crucial to better understand and predict their properties. Here, we use Small-angle X-ray scattering techniques to decipher the structure of the counterion cloud surrounding these DNA coated nanoparticles. Through the use of anomalous scattering techniques we have mapped the local concentrations of Rb+ ions in the region around the Protein-DNA constructs. These results are further corroborated with simulations using a geometric model for the excess charge density as function of radial distance from the protein core. Further, we investigate the influence of solution ionic strength on the structure of the DNA corona and demonstrate a reduction in the extension of the DNA corona with increasing concentration of NaCl in solution for the case of both single and double stranded DNA shells. Our work reveals the distribution of counterions in the vicinity of Protein-DNA conjugates and decouples the effect of solution ionic strength on the thickness of the DNA layer.

  4. The bond angle distribution and local coordination for silica glass under densification

    International Nuclear Information System (INIS)

    We present a simulation of silica glass with density ranging from 2.53 to 3.49 g cm-3 using the molecular dynamics method. The simulation reveals that the density of constructed samples can be expressed by a linear function of fraction of units SiOx. As the density increases, the fraction of units SiOx and linkages OSiy significantly varies, but partial bond angle distributions (BAD) for SiOx, x = 4, 5, 6, and OSiy, y = 2, 3, are identical for all the obtained samples. This allows us to establish a simple relation between total BAD and fraction of SiOx or OSiy. The simulation shows good agreement between the simulation and calculation results for both Si-O-Si and O-Si-O BAD. Moreover, most Si atoms in the low-density sample belong to the perfect tetrahedron (PT), whereas they are mainly present in the distorted tetrahedron for the high-density sample. We also found a large cluster of PTs that are linked to each other via bridging oxygen. The largest cluster consists of 90% Si in the low-density sample and 39% Si in the high-density one. (paper)

  5. Polyphase tectonic evolution of the Aksu Basin, Isparta Angle (Southern Turkey)

    Science.gov (United States)

    Üner, Serkan; Özsayin, Erman; Kutluay, Alkor; Dirik, Kadir

    2015-04-01

    The Aksu Basin, within the Isparta Angle, is located to the north of the intersection of the Aegean and Cyprus arcs and has been evolving since the Middle Miocene. Correlation of: (1) kinematic analysis of fault planes that cut the basin fill, (2) the reactivation/inversion of fault planes and (3) sedimentological data indicate that the Aksu Basin has evolved by four alternating compressional and extensional tectonic phases since its formation. The first phase was NW-SE oriented compression caused by the emplacement of the Lycian Nappe units which ended in Langhian. This compressional phase that induced the formation and the initial deformation of the basin was followed by a NW-SE extensional phase. This tectonic phase prevailed between the Langhian and Messinian and was terminated by a NE-SW compressional regime known as the Aksu Phase. The neotectonic period is characterized by NE-SW extension and began in the Late Pliocene. Correlation with the existing tectonic literature shows that the order of deformational phases proposed in this study might also be valid for the entire Isparta Angle area.

  6. New Archiving Distributed InfrastructuRe (NADIR): Status and Evolution

    Science.gov (United States)

    De Marco, M.; Knapic, C.; Smareglia, R.

    2015-09-01

    The New Archiving Distributed InfrastructuRe (NADIR) has been developed at INAF-OATs IA2 (Italian National Institute for Astrophysics - Astronomical Observatory of Trieste, Italian center of Astronomical Archives), as an evolution of the previous archiving and distribution system, used on several telescopes (LBT, TNG, Asiago, etc.) to improve performance, efficiency and reliability. At the present, NADIR system is running on LBT telescope and Vespa (Italian telescopes network for outreach) Ramella et al. (2014), and will be used on TNG, Asiago and IRA (Istituto Radio Astronomia) archives of Medicina, Noto and SRT radio telescopes Zanichelli et al. (2014) as the data models for radio data will be ready. This paper will discuss the progress status, the architectural choices and the solutions adopted, during the development and the commissioning phase of the project. A special attention will be given to the LBT case, due to some critical aspect of data flow and policies and standards compliance, adopted by the LBT organization.

  7. Probability Distribution Function Evolution for Binary Alloy Solidification

    Energy Technology Data Exchange (ETDEWEB)

    Steinzig, M.L.; Harlow, F.H.

    1999-02-26

    The thermally controlled solidification of a binary alloy, nucleated at isolated sites, is described by the evolution of a probability distribution function, whose variables include grain size and distance to nearest neighbor, together with descriptors of shape, orientation, and such material properties as orientation of nonisotropic elastic modulus and coefficient of thermal expansion. The relevant Liouville equation is described and coupled with global equations for energy and solute transport. Applications are discussed for problems concerning nucleation and impingement and the consequences for final size and size distribution. The goal of this analysis is to characterize the grain structure of the solidified casting and to enable the description of its probable response to thermal treatment, machining, and the imposition of mechanical insults.

  8. Precipitation particle charge distribution and evolution of East Asian rainbands

    Science.gov (United States)

    Takahashi, Tsutomu

    2012-11-01

    Numerous videosondes, balloon-borne surveyors of precipitation particle morphology and charge, have been launched into cloud systems in many, disparate locations in East Asia. Reported here are videosonde-based observations of early summer, Baiu rainbands at Tanegashima in southern Japan and of summer rainbands at Chiang Rai in northern Thailand. Precipitation particles are mapped by type and charge over the course of cloud development, allowing particle and charge evolution to be derived. The basic charge distribution as observed in Hokuriku winter thunderclouds at different cloud life stages was seen at different locations characterized by vertical velocity profiles in the cloud. The charge structure of the rainbands in both locations was a basic tripole. The major charge carriers were graupel and ice crystals. As graupel and ice crystal concentrations increased, not only did space charge increase, but per-particle charge also increased. Increased lightning activity was associated with higher particle space charge and lower cloud-top temperature. The particle charge evolution of these systems includes several fundamental features: a. active negative charging of graupel in an intense updraft, b. descent of negative graupel along the edge of an updraft column, c. merging of negative graupel with positively charged raindrops falling in the central cloud, and d. extended distribution of positive ice crystals in the stratiform cloud. The observations suggest that riming electrification was the main charge separation mechanism.

  9. Simultaneous distribution between the deflection angle and the lateral displacement under the Moliere theory of multiple scattering

    International Nuclear Information System (INIS)

    Simultaneous distribution between the deflection angle and the lateral displacement of fast charged particles traversing through matter is derived by applying numerical inverse Fourier transforms on the Fourier spectral density solved analytically under the Moliere theory of multiple scattering, taking account of ionization loss. Our results show the simultaneous Gaussian distribution at the region of both small deflection angle and lateral displacement, though they show the characteristic contour patterns of probability density specific to the single and the double scatterings at the regions of large deflection angle and/or lateral displacement. The influences of ionization loss on the distribution are also investigated. An exact simultaneous distribution is derived under the fixed energy condition based on a well-known model of screened single scattering, which indicates the limit of validity of the Moliere theory applied to the simultaneous distribution. The simultaneous distribution will be valuable for improving the accuracy and the efficiency of experimental analyses and simulation studies relating to charged particle transports. (orig.)

  10. Simultaneous distribution between the deflection angle and the lateral displacement under the Moliere theory of multiple scattering

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsuka, Takao [Okayama Shoka University, Laboratory of Information Science, Okayama (Japan); Okei, Kazuhide [Kawasaki Medical School, Dept. of Information Sciences, Kurashiki (Japan); Iyono, Atsushi [Okayama university of Science, Dept. of Fundamental Science, Faculty of Science, Okayama (Japan); Bielajew, Alex F. [Univ. of Michigan, Dept. Nuclear Engineering and Radiological Sciences, Ann Arbor, MI (United States)

    2015-12-15

    Simultaneous distribution between the deflection angle and the lateral displacement of fast charged particles traversing through matter is derived by applying numerical inverse Fourier transforms on the Fourier spectral density solved analytically under the Moliere theory of multiple scattering, taking account of ionization loss. Our results show the simultaneous Gaussian distribution at the region of both small deflection angle and lateral displacement, though they show the characteristic contour patterns of probability density specific to the single and the double scatterings at the regions of large deflection angle and/or lateral displacement. The influences of ionization loss on the distribution are also investigated. An exact simultaneous distribution is derived under the fixed energy condition based on a well-known model of screened single scattering, which indicates the limit of validity of the Moliere theory applied to the simultaneous distribution. The simultaneous distribution will be valuable for improving the accuracy and the efficiency of experimental analyses and simulation studies relating to charged particle transports. (orig.)

  11. Evolution of consumption distribution and model of wealth distribution in China between 1995 and 2012

    Science.gov (United States)

    Gao, Li

    2015-07-01

    We study the evolution of the distribution of consumption of individuals in the majority population in China during the period 1995-2012 and find that its probability density functions (PDFs) obey the rule Pc(x) = K(x - μ) e-(x - μ)2/2σ2. We also find (i) that the PDFs and the individual income distribution appear to be identical, (ii) that the peaks of the PDFs of the individual consumption distribution are consistently on the low side of the PDFs of the income distribution, and (iii) that the average of the marginal propensity to consume (MPC) is large, MPC bar = 0.77, indicating that in the majority population individual consumption is low and strongly dependent on income. The long right tail of the PDFs of consumption indicates that few people in China are participating in the high consumption economy, and that consumption inequality is high. After comparing the PDFs of consumption with the PDFs of income we obtain the PDFs of residual wealth during the period 1995-2012, which exhibit a Gaussian distribution. We use an agent-based kinetic wealth-exchange model (KWEM) to simulate this evolutional process and find that this Gaussian distribution indicates a strong propensity to save rather than spend. This may be due to an anticipation of such large potential outlays as housing, education, and health care in the context of an inadequate welfare support system.

  12. Microwave field distribution in a magic angle spinning dynamic nuclear polarization NMR probe

    Science.gov (United States)

    Nanni, Emilio A.; Barnes, Alexander B.; Matsuki, Yoh; Woskov, Paul P.; Corzilius, Björn; Griffin, Robert G.; Temkin, Richard J.

    2011-05-01

    We present a calculation of the microwave field distribution in a magic angle spinning (MAS) probe utilized in dynamic nuclear polarization (DNP) experiments. The microwave magnetic field (B 1 S) profile was obtained from simulations performed with the High Frequency Structure Simulator (HFSS) software suite, using a model that includes the launching antenna, the outer Kel-F stator housing coated with Ag, the RF coil, and the 4 mm diameter sapphire rotor containing the sample. The predicted average B 1 S field is 13 μT/W 1/2, where S denotes the electron spin. For a routinely achievable input power of 5 W the corresponding value is γSB 1 S = 0.84 MHz. The calculations provide insights into the coupling of the microwave power to the sample, including reflections from the RF coil and diffraction of the power transmitted through the coil. The variation of enhancement with rotor wall thickness was also successfully simulated. A second, simplified calculation was performed using a single pass model based on Gaussian beam propagation and Fresnel diffraction. This model provided additional physical insight and was in good agreement with the full HFSS simulation. These calculations indicate approaches to increasing the coupling of the microwave power to the sample, including the use of a converging lens and fine adjustment of the spacing of the windings of the RF coil. The present results should prove useful in optimizing the coupling of microwave power to the sample in future DNP experiments. Finally, the results of the simulation were used to predict the cross effect DNP enhancement ( ɛ) vs. ω1 S/(2 π) for a sample of 13C-urea dissolved in a 60:40 glycerol/water mixture containing the polarizing agent TOTAPOL; very good agreement was obtained between theory and experiment.

  13. Evolution of Particle Size Distributions in Fragmentation Over Time

    Science.gov (United States)

    Charalambous, C. A.; Pike, W. T.

    2013-12-01

    We present a new model of fragmentation based on a probabilistic calculation of the repeated fracture of a particle population. The resulting continuous solution, which is in closed form, gives the evolution of fragmentation products from an initial block, through a scale-invariant power-law relationship to a final comminuted powder. Models for the fragmentation of particles have been developed separately in mainly two different disciplines: the continuous integro-differential equations of batch mineral grinding (Reid, 1965) and the fractal analysis of geophysics (Turcotte, 1986) based on a discrete model with a single probability of fracture. The first gives a time-dependent development of the particle-size distribution, but has resisted a closed-form solution, while the latter leads to the scale-invariant power laws, but with no time dependence. Bird (2009) recently introduced a bridge between these two approaches with a step-wise iterative calculation of the fragmentation products. The development of the particle-size distribution occurs with discrete steps: during each fragmentation event, the particles will repeatedly fracture probabilistically, cascading down the length scales to a final size distribution reached after all particles have failed to further fragment. We have identified this process as the equivalent to a sequence of trials for each particle with a fixed probability of fragmentation. Although the resulting distribution is discrete, it can be reformulated as a continuous distribution in maturity over time and particle size. In our model, Turcotte's power-law distribution emerges at a unique maturation index that defines a regime boundary. Up to this index, the fragmentation is in an erosional regime with the initial particle size setting the scaling. Fragmentation beyond this index is in a regime of comminution with rebreakage of the particles down to the size limit of fracture. The maturation index can increment continuously, for example under

  14. Evolution and Distribution of Saxitoxin Biosynthesis in Dinoflagellates

    Directory of Open Access Journals (Sweden)

    Kjetill S. Jakobsen

    2013-08-01

    Full Text Available Numerous species of marine dinoflagellates synthesize the potent environmental neurotoxic alkaloid, saxitoxin, the agent of the human illness, paralytic shellfish poisoning. In addition, certain freshwater species of cyanobacteria also synthesize the same toxic compound, with the biosynthetic pathway and genes responsible being recently reported. Three theories have been postulated to explain the origin of saxitoxin in dinoflagellates: The production of saxitoxin by co-cultured bacteria rather than the dinoflagellates themselves, convergent evolution within both dinoflagellates and bacteria and horizontal gene transfer between dinoflagellates and bacteria. The discovery of cyanobacterial saxitoxin homologs in dinoflagellates has enabled us for the first time to evaluate these theories. Here, we review the distribution of saxitoxin within the dinoflagellates and our knowledge of its genetic basis to determine the likely evolutionary origins of this potent neurotoxin.

  15. AGIS: Evolution of Distributed Computing information system for ATLAS

    Science.gov (United States)

    Anisenkov, A.; Di Girolamo, A.; Alandes, M.; Karavakis, E.

    2015-12-01

    ATLAS, a particle physics experiment at the Large Hadron Collider at CERN, produces petabytes of data annually through simulation production and tens of petabytes of data per year from the detector itself. The ATLAS computing model embraces the Grid paradigm and a high degree of decentralization of computing resources in order to meet the ATLAS requirements of petabytes scale data operations. It has been evolved after the first period of LHC data taking (Run-1) in order to cope with new challenges of the upcoming Run- 2. In this paper we describe the evolution and recent developments of the ATLAS Grid Information System (AGIS), developed in order to integrate configuration and status information about resources, services and topology of the computing infrastructure used by the ATLAS Distributed Computing applications and services.

  16. Multi-Angle Simulation of Flavor Evolution in the Neutrino Neutronization Burst From an O-Ne-Mg Core-Collapse Supernova

    CERN Document Server

    Cherry, John F; Carlson, Joe; Duan, Huaiyu; Qian, Yong-Zong

    2010-01-01

    We report results of the first 3-by-3 "multi-angle" simulation of the evolution of neutrino flavor in the core collapse supernova environment. In particular, we follow neutrino flavor transformation in the neutronization neutrino burst of an O-Ne-Mg core collapse event. Though in qualitative sense our results are consistent with those obtained in 3-by-3 single-angle simulations, at least in terms of neutrino mass hierarchy dependence, performing multi-angle calculations is found to reduce the adiabaticity of flavor evolution in the normal neutrino mass hierarchy, resulting in lower swap energies. Our simulations also show that current uncertainties in the measured mass-squared and mixing angle parameters translate into uncertainties in neutrino swap energies. Our results show that at low theta-13 it may be difficult to resolve the neutrino mass hierarchy in the O-Ne-Mg neutronization neutrino burst.

  17. Small-angle scattering study of mesoscopic structures in charged gel and their evolution on dehydration

    DEFF Research Database (Denmark)

    Sugiyama, Masaaki; Annaka, Masahiko; Hara, Kazuhiro;

    2003-01-01

    reveal that, depending upon the [NIPA]/[SA] ratio, the dehydrated NIPA-SA gel shows two mesoscopic structures: one consists of randomly distributed SA-rich islands in NIPA matrix, while the other is a microphase-separated structure, composed of NIPA-rich and SA-rich domains. In addition, the SANS...... experiments reveal the mesoscopic structural features during the dehydration process. As the concentration of the network polymers increases, NIPA-rich and water-rich domains segregate in the gel. Then, an electrostatic interaction between the segregated domains induces a microphase-separated structure in the...... limit of the dehydrated NIPA-SA gel....

  18. Measurement of Diurnal Body Tilt Angle Distributions of Threeline Grunt Parapristipoma trilineatum Using Micro-Acceleration Data Loggers

    Directory of Open Access Journals (Sweden)

    Hideaki Tanoue

    2013-07-01

    Full Text Available The body tilt angle of a fish has a large effect on the acoustic target strength. For an accurate estimation of fish abundance using acoustic methods, it is necessary to measure body tilt angles in free-ranging fish. We measured diurnal body tilt angle distributions of threeline grunt (Parapristipoma trilineatum while swimming in schools in a fish cage. Micro-acceleration data loggers were used to record (for 3 days swaying and surging accelerations (at 16 Hz intervals of 10 individuals among 20 forming a school in a fish cage. Time series analysis of 1-h mean body tilt angles revealed significant differences in body tilt angles between day (−7.9 ± 3.28° and night (0.8 ± 5.89°, which must be taken into account when conducting acoustic surveys. These results will be useful for calculating the average dorsal aspect target strength (TS of threeline grunt for accurate estimations of fish abundance.

  19. A laser speckle sensor to measure the distribution of static torsion angles of twisted targets

    DEFF Research Database (Denmark)

    Rose, B.; Imam, H.; Hanson, Steen Grüner;

    1998-01-01

    cylindrical lens serves to image the closely spaced lateral positions of the target along the twist axis onto corresponding lines of the two dimensional image sensor. Thus, every single line of the image sensor measures the torsion angle of the corresponding surface position along the twist axis of the target...

  20. Signatures of the various regions of the outer magnetosphere in the pitch angle distributions of energetic particles

    Energy Technology Data Exchange (ETDEWEB)

    West, H.I. Jr.

    1978-12-11

    An account is given of the obervations of the pitch angle distributions of energetic particles in the near equatorial regions of the Earth's magnetosphere. The emphasis is on relating the observed distributions to the field configuration responsible for the observed effects. The observed effects relate to drift-shell splitting, to the breakdown of adiabatic guiding center motion in regions of sharp field curvature relative to partial gyro radii, to wave-particle interactions, and to moving field configurations. 39 references.

  1. Growth of epitaxial CrN on MgO(001): Role of deposition angle on surface morphological evolution

    International Nuclear Information System (INIS)

    CrN layers, 6 to 500 nm thick, were grown on MgO(001) at 600 deg. C by ultra-high-vacuum magnetron sputter deposition in pure N2 discharges at 2.6 Pa. The deposition angle α with respect to the surface normal was varied from 0 deg. to 80 deg. in order to directly probe the effect of atomic shadowing on the surface morphological evolution. Layers grown with α 0 deg. are single crystals which develop a regular surface mound structure. At low layer thicknesses, t ≤ 25 nm, the surface mounds grow primarily vertically, due to kinetic roughening, and form square-shapes with edges along low-energy , directions. Continued growth at t ≥ 25 nm is dominated by mound-competition and coalescence which leads to a self-similar growth mode with increases in both mound height and width. Layers deposited from oblique angles α = 80 deg. also nucleate as single crystals with a cube-on-cube epitaxial relationship with the substrate. However, rough surfaces with cauliflower-type morphologies cause the nucleation of misoriented CrN grains that develop into cone-shaped grains that protrude out of the epitaxial matrix to form triangular faceted surface mounds. Atomic shadowing exacerbates the growth rate of these misoriented grains, causing a dramatic increase in the root-mean-square surface roughness, which is ∼ 16x higher for layers grown at α = 80 deg. than at α = 0 deg. The roughening follows a power-law with a roughening exponent β that increases from 0.37 ± 0.04 to 0.57 ± 0.15 as α is increased from 0 deg. to 80 deg. This increase is attributed to a transition from kinetic roughening to roughening caused by atomic shadowing effects

  2. Distribution functions for internal interface energy as a characteristic of submicrocrystalline copper structure evolution under low-temperature annealing

    Science.gov (United States)

    Kuznetsov, P.; Rakhmatulina, T.; Koznikov, A.; Belyaeva, I.

    2015-10-01

    Submicrocrystalline structure of 99.99% pure copper produced by equal channel angular pressing was under investigation. After deformation the samples were subjected to low-temperature annealing. Grain and subgrain structure was studied by scanning tunnel microscopy. Internal interface energy was estimated using the method based on measurement of dihedral angles (ψ) of the boundary grooves formed by electrochemical etching. Analysis of the differential and cumulative distribution functions for relative grain boundary energy enabled to qualitatively evaluate energy redistribution between the boundaries of different types and internal bulk crystallites and to study evolution of submicrocrystalline structure under low-temperature annealing.

  3. Multiphased tectonic evolution of the Central Algerian margin from combined wide-angle and reflection seismic data off Tipaza, Algeria

    Science.gov (United States)

    Leprêtre, A.; Klingelhoefer, F.; Graindorge, D.; Schnurle, P.; Beslier, M. O.; Yelles, K.; Déverchère, J.; Bracene, R.

    2013-08-01

    The origin of the Algerian margin remains one of the key questions still discussed in the Western Mediterranean sea, due to the imprecise nature and kinematics of the associated basin during the Neogene. For the first time, the deep structure of the Maghrebian margin was explored during the SPIRAL seismic survey. In this work, we present a N-S transect off Tipaza (west of Algiers), a place where the margin broadens due to a topographic high (Khayr-al-Din Bank). New deep penetration seismic profiles allow us to image the sedimentary sequence in the Algerian basin and the crustal structure at the continent-ocean boundary. Modeling of the wide-angle data shows thinning of the basement, from more than 15km in the continental upper margin to only 5-6km of oceanic-type basement in the Algerian basin, and reveals a very narrow or absent transitional zone. Analysis of the deep structure of the margin indicates features inherited from its complex evolution: (1) an oceanic-type crust in the deep basin, (2) similarities with margins formed in a transform-type setting, (3) a progressive deepening of the whole sedimentary cover, and the thickening of the Plio-Quaternary sediments at the margin foot, coeval with (4) a downward flexure of the basement in the basin. These features argue for a multiphased evolution of the margin, including (1) an early stage of rifting and/or spreading, (2) a late transcurrent episode related to the westward migration of the Alboran domain, and (3) a diffuse Plio-Quaternary compressional reactivation of the margin.

  4. Azimuth angle distribution of thermal-infrared temperature over rice canopy with row orientation

    International Nuclear Information System (INIS)

    Using ground-based and airborne observation, as well as numerical simulation, we confirmed that the thermal-infrared temperature (TIT) of a rice canopy surface with row orientation changes with azimuth viewing angle. The TIT of the direction parallel to row orientation is 1-4degC higher than that of the other directions. The TIT differences occur during the daytime, and for a leaf area index (LAI) around 0.5-3 because the field of view of an infrared thermometer viewing a direction parallel to the rows contains much more of the water surface under the rice canopy than the plant surface of the canopy. The temperature of the water surface between rows is much higher than that of the plant surface, because the intense incoming solar radiation near noon is not absorbed by the canopy and so warms the water efficiently. Matsushima and Kondo (1997) developed a radiation transfer model for TIT of a rice canopy surface, and confirmed a nadir viewing angle dependence of TIT of according to leaf area index. Based on the above model, a model of a rice canopy with row orientation was developed to investigate the TIT variation with azimuth viewing angle. The model design employs the ratio of the apparent areas of the plant surface and the underground water surface, which change with the azimuth and nadir viewing angles, and reproduces the observation well. These results indicate that the main cause of the TIT difference is the ratio of the apparent areas of the plant surface and the water surface when the temperature of the water surface is much higher than that of the plant surface. The TIT in a westerly direction exceeds that of the other directions shortly after sunrise because the solar elevation is low and the azimuth of the sun is around east. This is because the plant surface temperature exceeds that of the water surface, which is opposite the near noon cases. On the scale of a satellite grid, a simple numerical experiment demonstrated that the TIT difference of azimuth

  5. Temperature distribution and evolution characteristic in lightning return stroke channel

    Science.gov (United States)

    Mu, Yali; Yuan, Ping; Wang, Xuejuan; Dong, Caixia

    2016-07-01

    According to the time-resolved spectra of four lightning return strokes, the temperatures of arc core channel and the peripheral optical channel surrounding the arc core are investigated by different methods; the temperature distribution along the radial direction of channel on the peak current stage is discussed. The results show that a temperature gradient is formed along the radial direction of channel during the discharge process. With the increasing of the radius, the temperature decreases gradually. The temperature of arc core channel is about 4000-5000 K higher than that of the peripheral optical channel. The time evolution of channel temperature shows that the falling of the temperature is very slow compared with the decreasing of the current after their peak values. After the peak current, the channel temperature is still maintained at around 20,000 K up to 200-400 μ s . The heat effect resulting from such a long-time high temperature is the main source of most direct lightning disasters.

  6. Statistical Quadrature Evolution for Continuous-Variable Quantum Key Distribution

    Science.gov (United States)

    Gyongyosi, Laszlo; Imre, Sandor

    2016-05-01

    We propose a statistical quadrature evolution (SQE) method for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD protocol utilizes Gaussian subcarrier quantum continuous variables (CV) for information transmission. The SQE framework provides a minimal error estimate of the quadratures of the CV quantum states from the discrete, measured noisy subcarrier variables. We define a method for the statistical modeling and processing of noisy Gaussian subcarrier quadratures. We introduce the terms statistical secret key rate and statistical private classical information, which quantities are derived purely by the statistical functions of our method. We prove the secret key rate formulas for a multiple access multicarrier CVQKD. The framework can be established in an arbitrary CVQKD protocol and measurement setting, and are implementable by standard low-complexity statistical functions, which is particularly convenient for an experimental CVQKD scenario. This work was partially supported by the GOP-1.1.1-11-2012-0092 project sponsored by the EU and European Structural Fund, by the Hungarian Scientific Research Fund - OTKA K-112125, and by the COST Action MP1006.

  7. On turbulence driven by axial precession and tidal evolution of the spin-orbit angle of close-in giant planets

    Science.gov (United States)

    Barker, Adrian J.

    2016-08-01

    The spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. This induces internal fluid motions inside the planet that are subject to a hydrodynamic instability. We study the turbulent damping of precessional fluid motions, as a result of this instability, in the simplest local computational model of a giant planet (or star), with and without a weak internal magnetic field. Our aim is to determine the outcome of this instability, and its importance in driving tidal evolution of the spin-orbit angle in precessing planets (and stars). We find that this instability produces turbulent dissipation that is sufficiently strong that it could drive significant tidal evolution of the spin-orbit angle for hot Jupiters with orbital periods shorter than about 10-18 d. If this mechanism acts in isolation, this evolution would be towards alignment or anti-alignment, depending on the initial angle, but the ultimate evolution (if other tidal mechanisms also contribute) is expected to be towards alignment. The turbulent dissipation is proportional to the cube of the precession frequency, so it leads to much slower damping of stellar spin-orbit angles, implying that this instability is unlikely to drive evolution of the spin-orbit angle in stars (either in planetary or close binary systems). We also find that the instability-driven flow can act as a system-scale dynamo, which may play a role in producing magnetic fields in short-period planets.

  8. On turbulence driven by axial precession and tidal evolution of the spin-orbit angle of close-in giant planets

    Science.gov (United States)

    Barker, Adrian J.

    2016-08-01

    The spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. This induces internal fluid motions inside the planet that are subject to a hydrodynamic instability. We study the turbulent damping of precessional fluid motions, as a result of this instability, in the simplest local computational model of a giant planet (or star), with and without a weak internal magnetic field. Our aim is to determine the outcome of this instability, and its importance in driving tidal evolution of the spin-orbit angle in precessing planets (and stars). We find that this instability produces turbulent dissipation that is sufficiently strong that it could drive significant tidal evolution of the spin-orbit angle for hot Jupiters with orbital periods shorter than about 10-18 days. If this mechanism acts in isolation, this evolution would be towards alignment or anti-alignment, depending on the initial angle, but the ultimate evolution (if other tidal mechanisms also contribute) is expected to be towards alignment. The turbulent dissipation is proportional to the cube of the precession frequency, so it leads to much slower damping of stellar spin-orbit angles, implying that this instability is unlikely to drive evolution of the spin-orbit angle in stars (either in planetary or close binary systems). We also find that the instability-driven flow can act as a system-scale dynamo, which may play a role in producing magnetic fields in short-period planets.

  9. Grain size effects on He bubbles distribution and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Gao, X.; Gao, N. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Z.G., E-mail: zhgwang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Cui, M.H.; Wei, K.F.; Yao, C.F.; Sun, J.R.; Li, B.S.; Zhu, Y.B.; Pang, L.L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Y.F. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang, D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xie, E.Q. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)

    2015-02-15

    Highlights: • SMAT treated T91 and conventional T91 were implanted by 200 keV He{sup 2+} to 1 × 10{sup 21} He m{sup −2} at room temperature and annealed at 450 °C for 3.5 h. • He bubbles in nanometer-size-grained T91 are smaller in as-implanted case. • The bubbles in the matrix of nanograins were hard to detect and those along the nanograin boundaries coalesced and filled with the grain boundaries after annealing. • Brownian motion and coalescence and Ostwald ripening process might lead to bubbles morphology presented in the nanometer-size-grained T91 after annealing. - Abstract: Grain boundary and grain size effects on He bubble distribution and evolution were investigated by He implantation into nanometer-size-grained T91 obtained by Surface Mechanical Attrition Treatment (SMAT) and the conventional coarse-grained T91. It was found that bubbles in the nanometer-size-grained T91 were smaller than those in the conventional coarse-grained T91 in as-implanted case, and bubbles in the matrix of nanograins were undetectable while those at nanograin boundaries (GBs) coalesced and filled in GBs after heat treatment. These results suggested that the grain size of structural material should be larger than the mean free path of bubble’s Brownian motion and/or denuded zone around GBs in order to prevent bubbles accumulation at GBs, and multiple instead of one type of defects should be introduced into structural materials to effectively reduce the susceptibility of materials to He embrittlement and improve the irradiation tolerance of structural materials.

  10. Determination of the spatial distribution of multiple fluid phases in porous media by ultra-small-angle neutron scattering

    International Nuclear Information System (INIS)

    In the present work contrast-matching USANS (ultra-small-angle neutron scattering) was employed in order to determine the spatial distribution of immiscible fluids confined within a macroporous α-Al2O3 membrane. Water-air as well as water-hydrocarbon and hydrocarbon-air systems were examined and the analysis of the results, also on the basis of a complementary numerical study provided significant information on the behaviour of the multiphase ensemble as it has been demonstrated that the individual fluids occupy certain positions in the pore space, regardless of the actual values of the respective interfacial properties.

  11. Efficiency enhancement and angle-dependent color change in see-through organic photovoltaics using distributed Bragg reflectors

    Science.gov (United States)

    Dong, Wan Jae; Lo, Nhat-Truong; Jung, Gwan Ho; Ham, Juyoung; Lee, Jong-Lam

    2016-03-01

    A distributed Bragg reflector (DBR) is conducted as a bottom reflector in see-through organic photovoltaics (OPVs) with an active layer of poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester (P3HT:PCBM). The DBR consists of alternative layers of the high- and low-refractive index materials of Ta2O5 (n = 2.16) and SiO2 (n = 1.46). The DBR selectively reflects the light within a specific wavelength region (490 nm-630 nm) where the absorbance of P3HT:PCBM is maximum. The see-through OPVs fabricated on DBR exhibit efficiency enhancement by 31% compared to the device without DBR. Additionally, the angle-dependent transmittance of DBR is analysed using optical simulation and verified by experimental results. As the incident angle of light increases, peak of reflectance shifts to shorter wavelength and the bandwidth gets narrower. This unique angle-dependent optical properties of DBR allows the facile color change of see-through OPVs.

  12. Angle-resolved energy distributions of laser ablated silver ions in vacuum

    DEFF Research Database (Denmark)

    Hansen, T.N.; Schou, Jørgen; Lunney, J.G.

    1998-01-01

    The energy distributions of ions ablated from silver in vacuum have been measured in situ for pulsed laser irradiation at 355 nm. We have determined the energy spectra for directions ranging from 5 degrees to 75 degrees with respect to the normal in the intensity range from 100 to 400 MW/cm(2). At...

  13. Investigation of temporal evolution and spatial distribution of dust creation events in DITS campaign using visible CCD cameras in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Suk-Ho [Association EURATOM-CEA/Cadarache, IRFM/SIPP/GIPP, St. Paul les Durance 13108 (France)], E-mail: sukhhong@nfri.re.kr; Grisolia, Christian; Monier-Gabet, Pascale [Association EURATOM-CEA/Cadarache, IRFM/SIPP/GIPP, St. Paul les Durance 13108 (France)

    2009-06-15

    Images of wide-angle visible CCD cameras contain information on dust creation events (flaking) that occur during plasma operations. Due to the interaction with plasma, flakes entering into the plasma left straight line-like visible traces behind in the images. Analyzing these traces by image processing, the temporal evolution, spatial distribution, and statistics on dust creation events in DITS campaign in Tore Supra were obtained.

  14. Remote Sensing of Spatial Distributions of Greenhouse Gases in the Los Angles Basin

    Science.gov (United States)

    Fu, Dejian; Pongetti, Thomas J.; Sander, Stanley P.; Cheung, Ross; Stutz, Jochen; Park, Chang Hyoun; Li, Qinbin

    2011-01-01

    The Los Angeles air basin is a significant anthropogenic source of greenhouse gases and pollutants including CO2, CH4, N2O, and CO, contributing significantly to regional and global climate change. Recent legislation in California, the California Global Warming Solutions Act (AB32), established a statewide cap for greenhouse gas emissions for 2020 based on 1990 emissions. Verifying the effectiveness of regional greenhouse gas emissions controls requires high-precision, regional-scale measurement methods combined with models that capture the principal anthropogenic and biogenic sources and sinks. We present a novel approach for monitoring the spatial distributions of greenhouse gases in the Los Angeles basin using high resolution remote sensing spectroscopy. We participated in the CalNex 2010 campaign to provide greenhouse gas distributions for comparison between top-down and bottom-up emission estimates.

  15. Using Hybrid Angle/Distance Information for Distributed Topology Control in Vehicular Sensor Networks

    OpenAIRE

    Chao-Chi Huang; Yang-Hung Chiu; Chih-Yu Wen

    2014-01-01

    In a vehicular sensor network (VSN), the key design issue is how to organize vehicles effectively, such that the local network topology can be stabilized quickly. In this work, each vehicle with on-board sensors can be considered as a local controller associated with a group of communication members. In order to balance the load among the nodes and govern the local topology change, a group formation scheme using localized criteria is implemented. The proposed distributed topology control meth...

  16. Early-stage evolution of particle size distribution with Johnson's SB function due to Brownian coagulation

    International Nuclear Information System (INIS)

    The moment method can be used to determine the time evolution of particle size distribution due to Brownian coagulation based on the general dynamic equation (GDE). But the function form of the initial particle size distribution must be determined beforehand for the moment method. If the assumed function type of the initial particle size distribution has an obvious deviation from the true particle population, the evolution of particle size distribution may be different from the real evolution tendency. Thus, a simple and general method is proposed based on the moment method. In this method, the Johnson's SB function is chosen as a general distribution function to fit the initial distributions including the log normal (L-N), Rosin–Rammler (R-R), normal (N-N) and gamma distribution functions, respectively. Meanwhile, using the modified beta function to fit the L-N, R-R, N-N and gamma functions is also conducted as a comparison in order to present the advantage of the Johnson's SB function as the general distribution function. And then, the time evolution of particle size distributions using the Johnson's SB function as the initial distribution can be obtained by several lower order moment equations of the Johnson's SB function in conjunction with the GDE during the Brownian coagulation process. Simulation experiments indicate that fairly reasonable results of the time evolution of particle size distribution can be obtained with this proposed method in the free molecule regime, transition regime and continuum plus near continuum regime, respectively, at the early time stage of evolution. The Johnson's SB function has the ability of describing the early time evolution of different initial particle size distributions. (paper)

  17. Asymptotic Fitness Distribution in the Bak-Sneppen Model of Biological Evolution with Four Species

    Science.gov (United States)

    Schlemm, Eckhard

    2012-08-01

    We suggest a new method to compute the asymptotic fitness distribution in the Bak-Sneppen model of biological evolution. As applications we derive the full asymptotic distribution in the four-species model, and give an explicit linear recurrence relation for a set of coefficients determining the asymptotic distribution in the five-species model.

  18. Asymptotic fitness distribution in the Bak-Sneppen model of biological evolution with four species

    OpenAIRE

    Schlemm, Eckhard

    2012-01-01

    We suggest a new method to compute the asymptotic fitness distribution in the Bak-Sneppen model of biological evolution. As applications we derive the full asymptotic distribution in the four-species model, and give an explicit linear recurrence relation for a set of coefficients determining the asymptotic distribution in the five-species model.

  19. Efficient evolution of unpolarized and polarized parton distributions with QCD-PEGASUS

    CERN Document Server

    Vogt, A

    2004-01-01

    The Fortran package QCD-PEGASUS is presented. This program provides fast, flexible and accurate solutions of the evolution equations for unpolarized and polarized parton distributions of hadrons in perturbative QCD. The evolution is performed using the symbolic moment-space solutions on a one-fits-all Mellin inversion contour. User options include the order of the evolution including the next-to-next-to-leading order in the unpolarized case, the type of the evolution including an emulation of brute-force solutions, the evolution with a fixed number n_f of flavours or in the variable-n_f scheme, and the evolution with a renormalization scale unequal to the factorization scale. The initial distributions are needed in a form facilitating the computation of the complex Mellin moments.

  20. Energy distributions of plume ions from silver at different angles ablated in vacuum

    DEFF Research Database (Denmark)

    Christensen, Bo Toftmann; Schou, Jørgen; Canulescu, Stela

    A typical pulsed laser deposition (PLD) is carried out for a fluence between 0.5 and 2.5 J/cm2. The ablated particles are largely neutrals at the lowest fluence, but the fraction of ions increases strongly with fluence and accounts for more 0.5 of the particles at 2.5 J/cm2 [1,2]. Since it may be...... comparatively difficult to measure the energy and angular distribution of neutrals, measurements of the ionic fraction will be valuable for any modeling of PLD. We have irradiated silver in a vacuum chamber (~ 10-7 mbar) with a Nd:YAG laser at a wavelength of 355 nm and made detailed measurements of the time...

  1. Spatial distribution and evolution of cerebral microbleeds: impact on the clinical therapy

    International Nuclear Information System (INIS)

    Cerebral microbleeds reflect the pathological changes of cerebral small vessel diseases. It has characterized spatial distribution and evolution. The occurrence of microbleeds impacts on clinical treatment. Susceptibility weighted imaging can improve the detection of cerebral microbleeds which could help for the diagnosis and differential diagnosis. We reviewed the pathology, characteristics of spatial and evolution of cerebral microbleeds and its impact on clinical therapy. (authors)

  2. Evolution and change of He bubbles in He-containing Ti films upon thermal treatment studied by small-angle X-ray scattering and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Guangai [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Wu, Erdong, E-mail: ewu@imr.ac.cn [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Huang, Chaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Cheng, Chun [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yan, Guanyun [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, Xiaolin [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Liu, Shi [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Tian, Qiang; Chen, Bo [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wu, Zhonghua [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Liu, Yi; Wang, Jie [Institute of Shanghai Apply Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2014-05-02

    Evolution and change of He bubbles in magnetron sputtering prepared He-containing Ti films under thermal treatment are studied by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and X-ray diffraction. Incorporation of He introduces a large number of He-vacancy clusters and some voids in the films, and significantly increases SAXS intensity and causes anisotropic scattering. The change of He induced defects during annealing is affected by thermal diffusion and migration of trapped He to the surface and between interfaces of He induced defects within the films. Annealing at 200 and 400 °C reduces intensity and anisotropy of SAXS, in accord with observed shrinking and disappearance of the voids. The simultaneous growth of non-uniformly distributed He bubbles to the sizes of 1–2 nm and a population level of 10{sup 5}/μm{sup 3} are detected in the temperature range. The changes are explained by migration and coalescence mechanisms, which requires low apparent activation energy. Inconsistence between TEM and SAXS observations is noted and attributed to thinning induced internal stress relaxation of TEM specimen. Remarkable enlargement of He bubbles, associated with increased SAXS intensity and fractal dimension, is observed after 600 °C annealing, indicating involvement of Ostwald Ripening (OR) mechanism. The OR process dominates at 800 °C, where the high temperature provides activation energy for accelerated He dissociation from small bubbles into larger ones, and generating textured microstructure and agglomerated bubble clusters. The inhomogeneous bubble size distribution observed at this temperature covers a broad range of about 10–50 nm and possessing a population density level of 10{sup 3}/μm{sup 3}. - Highlights: • Change of He bubbles in thermally treated Ti–He films is studied by SAXS and TEM. • SAXS reveals size distribution and fractional population of He bubbles in films. • He-vacancy clusters in Ti–He film

  3. Evolution and change of He bubbles in He-containing Ti films upon thermal treatment studied by small-angle X-ray scattering and transmission electron microscopy

    International Nuclear Information System (INIS)

    Evolution and change of He bubbles in magnetron sputtering prepared He-containing Ti films under thermal treatment are studied by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and X-ray diffraction. Incorporation of He introduces a large number of He-vacancy clusters and some voids in the films, and significantly increases SAXS intensity and causes anisotropic scattering. The change of He induced defects during annealing is affected by thermal diffusion and migration of trapped He to the surface and between interfaces of He induced defects within the films. Annealing at 200 and 400 °C reduces intensity and anisotropy of SAXS, in accord with observed shrinking and disappearance of the voids. The simultaneous growth of non-uniformly distributed He bubbles to the sizes of 1–2 nm and a population level of 105/μm3 are detected in the temperature range. The changes are explained by migration and coalescence mechanisms, which requires low apparent activation energy. Inconsistence between TEM and SAXS observations is noted and attributed to thinning induced internal stress relaxation of TEM specimen. Remarkable enlargement of He bubbles, associated with increased SAXS intensity and fractal dimension, is observed after 600 °C annealing, indicating involvement of Ostwald Ripening (OR) mechanism. The OR process dominates at 800 °C, where the high temperature provides activation energy for accelerated He dissociation from small bubbles into larger ones, and generating textured microstructure and agglomerated bubble clusters. The inhomogeneous bubble size distribution observed at this temperature covers a broad range of about 10–50 nm and possessing a population density level of 103/μm3. - Highlights: • Change of He bubbles in thermally treated Ti–He films is studied by SAXS and TEM. • SAXS reveals size distribution and fractional population of He bubbles in films. • He-vacancy clusters in Ti–He film transfer to bubbles and

  4. Avalanche dynamics in Bak-Sneppen evolution model observed with standard distribution width of fitness

    OpenAIRE

    Lee, Chaohong; Zhu, Xiwen; Gao, Kelin

    2001-01-01

    We introduce the standard distribution width of fitness to characterize the global and individual features of a ecosystem in the Bak-Sneppen evolution model. Through tracking this quantity in evolution, a different hierarchy of avalanche dynamics, $w_{0}$ avalanche is observed. The corresponding gap equation and the self-organized threshold $w_{c}$ are obtained. The critical exponents $\\tau ,$ $\\gamma $and $\\rho $, which describe the behavior of the avalanche size distribution, the average av...

  5. Control of the Diameter and Chiral Angle Distributions during Production of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Nikolaev, Pavel

    2009-01-01

    Many applications of single wall carbon nanotubes (SWCNT), especially in microelectronics, will benefit from use of certain (n,m) nanotube types (metallic, small gap semiconductor, etc.) Especially fascinating is the possibility of quantum conductors that require metallic armchair nanotubes. However, as produced SWCNT samples are polydisperse, with many (n,m) types present and typical approx.1:2 metal/semiconductor ratio. Nanotube nucleation models predict that armchair nuclei are energetically preferential due to formation of partial triple bonds along the armchair edge. However, nuclei can not reach any meaningful thermal equilibrium in a rapidly expanding and cooling plume of carbon clusters, leading to polydispersity. In the present work, SWCNTs were produced by a pulsed laser vaporization (PLV) technique. The carbon vapor plume cooling rate was either increased by change in the oven temperature (expansion into colder gas), or decreased via "warm-up" with a laser pulse at the moment of nucleation. The effect of oven temperature and "warm-up" on nanotube type population was studied via photoluminescence, UV-Vis-NIR absorption and Raman spectroscopy. It was found that reduced temperatures leads to smaller average diameters, progressively narrower diameter distributions, and some preference toward armchair structures. "Warm-up" shifts nanotube population towards arm-chair structures as well, but the effect is small. Possible improvement of the "warm-up" approach to produce armchair SWCNTs will be discussed. These results demonstrate that PLV production technique can provide at least partial control over the nanotube (n,m) population. In addition, these results have implications for the understanding the nanotube nucleation mechanism in the laser oven.

  6. Asymmetric distribution of cone-shaped lipids in a highly curved bilayer revealed by a small angle neutron scattering technique

    International Nuclear Information System (INIS)

    We have investigated the lipid sorting in a binary small unilamellar vesicle (SUV) composed of cone-shaped (1,2-dihexanoyl-sn-glycero-3-phosphocholine: DHPC) and cylinder-shaped (1,2-dipalmitoyl-sn-glycero-3-phosphocholine: DPPC) lipids. In order to reveal the lipid sorting we adopted a contrast matching technique of small angle neutron scattering (SANS), which extracts the distribution of deuterated lipids in the bilayer quantitatively without steric modification of lipids as in fluorescence probe techniques. First the SANS profile of protonated SUVs at a film contrast condition showed that SUVs have a spherical shape with an inner radius of 190 A and a bilayer thickness of 40 A. The SANS profile of deuterated SUVs at a contrast matching condition showed a characteristic scattering profile, indicating an asymmetric distribution of cone-shaped lipids in the bilayer. The characteristic profile was described well by a spherical bilayer model. The fitting revealed that most DHPC molecules are localized in the outer leaflet. Thus the shape of the lipid is strongly coupled with the membrane curvature. We compared the obtained asymmetric distribution of the cone-shaped lipids in the bilayer with the theoretical prediction based on the curvature energy model.

  7. Distribution angle control of a light-emitting diode downlight lens with high color uniformity using a scattering polymer

    Science.gov (United States)

    Mochizuki, Keiichi; Oosumi, Kazumasa; Koizumi, Fumiaki; Shinohara, Yoshinori; Tagaya, Akihiro; Koike, Yasuhiro

    2015-06-01

    We have proposed a light-emitting diode (LED) downlight lens that is made of a highly scattered optical transmission (HSOT) polymer. The HSOT polymer contains optimized heterogeneous structures that produce homogeneously scattered light with forward directivity. The full width at half maximum of the illuminance distribution angle can be increased from 16.7° to 37.9° as the concentration of the scattering particles in the HSOT polymer LED downlight lenses of identical shape is increased from 0.015 to 0.100 wt%. The colors in an illuminated area are highly uniform, which is not discernible by the human eye, with a high output efficiency greater than 85 %.

  8. Evolution of knowledge about distribution of productive forces

    Directory of Open Access Journals (Sweden)

    Yevgeny Georgievich Animitsa

    2014-06-01

    Full Text Available The article presents systematization of scientific knowledge concerning distribution of productive forces. It is proved that the conception of distribution of productive forces has dual-natured matter. The authors put an emphasis on interpretation of three main “distribution of productive forces” paradigms, which were figured out from foreign and native theories. Each of these paradigms has its special features and characteristics. It is necessary to use the complex of methods and tools in order to analyze the distinguish features of the distribution in different historic steps. The article provides methodology of distribution of productive forces, which based on such categories as “time” and “space.” Nowadays, this approach is more convenient as allows to reach continuous development. This idea also corresponds to contemporary principles of distribution of productive forces: parsimony principle, spatial concentration principle, irregular distribution of productive forces principle. The authors made conclusion that the modern paradigm of distribution of productive forces will contribute to developing regional economics as a science.

  9. Evolution of One-Point Distributions from Gaussian Initial Fluctuations

    OpenAIRE

    Kofman, Lev; Bertschinger, Edmund; Gelb, James M.; Nusser, Adi; Dekel, Avishai

    1993-01-01

    We study the quasilinear evolution of the one-point probability density functions (PDFs) of the smoothed density and velocity fields in a cosmological gravitating system beginning with Gaussian initial fluctuations. Our analytic results are based on the Zel'dovich approximation and laminar flow. A numerical analysis extends the results into the multistreaming regime using the smoothed fields of a CDM N-body simulation. We find that the PDF of velocity, both Lagrangian and Eulerian, remains Ga...

  10. An investigation on effect of geometrical parameters on spray cone angle and droplet size distribution of a two-fluid atomizer

    International Nuclear Information System (INIS)

    A visual study is conducted to determine the effect of geometrical parameters of a two-fluid atomizer on its spray cone angle. The liquid (water) jets exit from six peripheral inclined orifices and are introduced to a high speed gas (air) stream in the gravitational direction. Using a high speed imaging system, the spray cone angle has been determined in constant operational conditions, i.e., Reynolds and Weber numbers for different nozzle geometries. Also, the droplet sizes (Sauter mean diameter) and their distributions have been determined using Malvern Master Sizer x. The investigated geometrical parameters are the liquid jet diameter, liquid port angle and the length of the gas-liquid mixing chamber. The results show that among these parameters, the liquid jet diameter has a significant effect on spray cone angle. In addition, an empirical correlation has been obtained to predict the spray cone angle of the present two-fluid atomizer in terms of nozzle geometries

  11. Critical Exponent of Species-Size Distribution in Evolution

    CERN Document Server

    Adami, C; Yirdaw, R; Adami, Christoph; Seki, Ryoichi; Yirdaw, Robel

    1998-01-01

    We analyze the geometry of the species- and genotype-size distribution in evolving and adapting populations of single-stranded self-replicating genomes: here programs in the Avida world. We find that a scale-free distribution (power law) emerges in complex landscapes that achieve a separation of two fundamental time scales: the relaxation time (time for population to return to equilibrium after a perturbation) and the time between mutations that produce fitter genotypes. The latter can be dialed by changing the mutation rate. In the scaling regime, we determine the critical exponent of the distribution of sizes and strengths of avalanches in a system without coevolution, described by first-order phase transitions in single finite niches.

  12. On turbulence driven by axial precession and tidal evolution of the spin-orbit angle of close-in giant planets

    CERN Document Server

    Barker, Adrian J

    2016-01-01

    The spin axis of a rotationally deformed planet is forced to precess about its orbital angular momentum vector, due to the tidal gravity of its host star, if these directions are misaligned. This induces internal fluid motions inside the planet that are subject to a hydrodynamic instability. We study the turbulent damping of precessional fluid motions, as a result of this instability, in the simplest local computational model of a giant planet (or star), with and without a weak internal magnetic field. Our aim is to determine the outcome of this instability, and its importance in driving tidal evolution of the spin-orbit angle in precessing planets (and stars). We find that this instability produces turbulent dissipation that is sufficiently strong that it could drive significant tidal evolution of the spin-orbit angle for hot Jupiters with orbital periods shorter than about 10-18 days. If this mechanism acts in isolation, this evolution would be towards alignment or anti-alignment, depending on the initial a...

  13. The period distribution of Cepheids: a test of stellar evolution

    Directory of Open Access Journals (Sweden)

    Groenewegen M.A.T.

    2015-01-01

    Full Text Available The period distributions of classical Cepheids in the Small and Large Magellanic Cloud are quite different. Using the TRILEGAL population synthesis code and a theoretical instability strip the ultimate aim is to understand these differences quantitatively. First results are presented for one area in the LMC using VMC NIR data.

  14. Statistical distribution of foveal transverse chromatic aberration, pupil centration, and angle psi in a population of young adult eyes

    Science.gov (United States)

    Rynders, Maurice; Lidkea, Bruce; Chisholm, William; Thibos, Larry N.

    1995-10-01

    Subjective transverse chromatic aberration (sTCA) manifest at the fovea was determined for a population of 85 young adults (19-38 years old) by means of a two-dimensional, two-color, vernier alignment technique. The statistical distribution of sTCA was well fitted by a bivariate Gaussian function with mean values that were not significantly different from zero in either the horizontal or the vertical direction. We conclude from this result that a hypothetical, average eye representing the population mean of human eyes with medium-sized pupils is free of foveal sTCA. However, the absolute magnitude of sTCA for any given individual was often significantly greater than zero and ranged from 0.05 to 2.67 arcmin for the red and the blue lights of a computer monitor (mean wavelengths, 605 and 497 nm, respectively). The statistical distribution of the absolute magnitude of sTCA was well described by a Rayleigh probability distribution with a mean of 0.8 arcmin. A simple device useful for population screening in a clinical setting was also tested and gave concordant results. Assuming that sTCA at the fovea is due to decentering of the pupil with respect to the visual axis, we infer from these results that the pupil is, on average, well centered in human eyes. The average magnitude of pupil decentration in individual eyes is less than 0.5 mm, which corresponds to psi =3 deg for the angle between the achromatic and the visual axes of the eye.

  15. Wide-scale evolution of magnetization distribution in ultrathin films

    Czech Academy of Sciences Publication Activity Database

    Kisielewski, M.; Maziewski, A.; Polyakova, T.; Zablotskyy, Vitaliy A.

    2004-01-01

    Roč. 69, č. 18 (2004), 184419/1-184419/7. ISSN 0163-1829 Grant ostatní: PSCSR(PL) 4T11B 006 24; ICAI-CT(XE) 2000-70018 Institutional research plan: CEZ:AV0Z1010914 Keywords : magnetization domains * distribution * ultrathin film Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.075, year: 2004

  16. AGIS: Evolution of Distributed Computing Information system for ATLAS

    CERN Document Server

    Anisenkov, Alexey; The ATLAS collaboration; Alandes Pradillo, Maria; Karavakis, Edward

    2015-01-01

    The variety of the ATLAS Computing Infrastructure requires a central information system to define the topology of computing resources and to store the different parameters and configuration data which are needed by the various ATLAS software components. The ATLAS Grid Information System is the system designed to integrate configuration and status information about resources, services and topology of the computing infrastructure used by ATLAS Distributed Computing applications and services.

  17. Evolution of the statistical distribution in a topological defect network

    Science.gov (United States)

    Xue, Fei; Wang, Xueyun; Socolenco, Ion; Gu, Yijia; Chen, Long-Qing; Cheong, Sang-Wook

    2015-11-01

    The complex networks of numerous topological defects in hexagonal manganites are highly relevant to vastly different phenomena from the birth of our cosmos to superfluidity transition. The topological defects in hexagonal manganites form two types of domain networks: type-I without and type-II with electric self-poling. A combined phase-field simulations and experimental study shows that the frequencies of domains with N-sides, i.e. of N-gons, in a type-I network are fitted by a lognormal distribution, whereas those in type-II display a scale-free power-law distribution with exponent ∼2. A preferential attachment process that N-gons with a larger N have higher probability of coalescence is responsible for the emergence of the scale-free networks. Since the domain networks can be observed, analyzed, and manipulated at room temperature, hexagonal manganites provide a unique opportunity to explore how the statistical distribution of a topological defect network evolves with an external electric field.

  18. Transverse-momentum-dependent gluon distributions from JIMWLK evolution

    CERN Document Server

    Marquet, C; Roiesnel, C

    2016-01-01

    Transverse-momentum-dependent (TMD) gluon distributions have different operator definitions, depending on the process under consideration. We study that aspect of TMD factorization in the small-x limit, for the various unpolarized TMD gluon distributions encountered in the literature. To do this, we consider di-jet production in hadronic collisions, since this process allows to be exhaustive with respect to the possible operator definitions, and is suitable to be investigated at small x. Indeed, for forward and nearly back-to-back jets, one can apply both the TMD factorization and Color Glass Condensate (CGC) approaches to compute the di-jet cross-section, and compare the results. Doing so, we show that both descriptions coincide, and we show how to express the various TMD gluon distributions in terms of CGC correlators of Wilson lines, while keeping Nc finite. We then proceed to evaluate them by solving the JIMWLK equation numerically. We obtain that at large transverse momentum, the process dependence essen...

  19. Evolution of the trapped charge distribution due to trap emptying processes in a natural aluminosilicate

    International Nuclear Information System (INIS)

    The evolution of the thermoluminescence glow curve of a natural Ca-Be rich aluminosilicate after annealing treatments at different temperatures has been studied in order to evaluate the changes in the trapped charge distribution. The glow curve consists of a single broad peak that continuously shifts toward higher temperatures when the sample is preheated up to increasing temperatures, thus indicating the presence of a continuous trap distribution. The glow curve fitting assuming different distribution functions shows how a gaussian distribution becomes a nearly exponential distribution owing to the thermal leakage of charge carriers from trapping centres. (authors)

  20. Evolution of the distribution of wealth in an economic environment driven by local Nash equilibria

    OpenAIRE

    Degond, Pierre; Liu, Jian-guo; Ringhofer, Christian

    2013-01-01

    We present and analyze a model for the evolution of the wealth distribution within a heterogeneous economic environment. The model considers a system of rational agents interacting in a game theoretical framework, through fairly general assumptions on the cost function. This evolution drives the dynamic of the agents in both wealth and economic configuration variables. We consider a regime of scale separation where the large scale dynamics is given by a hydrodynamic closure with a Nash equili...

  1. Light-Ray Evolution Equations and Leading-Twist Parton Helicity-Dependent Nonforward Distributions

    CERN Document Server

    Balitsky, Yu Yu

    1997-01-01

    We discuss the calculation of the evolution kernels \\Delta W_{\\zeta}(X,Z) for the leading-twist nonforward parton distributions G_\\zeta(X,t) sensitive to parton helicities. We present our results for the kernels governing evolution of the relevant light-ray operators and describe a simple method allowing to obtain from them the components of the nonforward kernels \\Delta W_{\\zeta}(X,Z).

  2. Evaluation of size distribution of starch granules in selected wheat varieties by the Low Angle Laser Light Scattering method

    International Nuclear Information System (INIS)

    The distribution of the size of wheat starch granules using the method LALLS (Low Angle Laser Light Scattering), followed by the evaluation of the effect of variety, experimental site and intensity of cultivation on the vol. % of the starch A (starch granules > 10 μm) was determined. The total starch content and crude protein content in dry matter of flour T530 in selected collection of five winter wheat varieties were determined. Vol. % of the starch A in evaluated collection of wheat varieties varied between 65.31 and 72.34%. The effect of a variety on the vol. % of starch A seemed to be more marked than the effect of site and intensity of cultivation. The highest vol. % of starch A reached evaluated varieties from the quality group C, i.e. varieties unsuitable for baking utilisation (except variety Contra with high total content of starch in dry matter of flour T530, but relatively low vol. % of starch A). A low vol. % of starch A was also found in the variety Hana (very good variety for baking utilisation). Certain variety differences followed from the evaluation of distribution of starch fractions of starch granules, forming starch A. In the case of varieties Hana, Contra and Siria higher representation of fractions up to 30 μm was recorded, while starch A in the varieties Estica and Versailles was formed in higher degree by size fractions of starch granules over 30 μm and particularly size fraction > 50 μm was greatest in these varieties of all evaluated samples. With increasing total starch content in dry matter of flour T530 the crude protein content decreased; the vol. % of starch A not always increased proportionally with increasing total starch content. (author)

  3. Peptide-induced Asymmetric Distribution of Charged Lipids in a Vesicle Bilayer Revealed by Small-Angle Neutron Scattering

    Science.gov (United States)

    Heller, William; Qian, Shuo

    2012-02-01

    Cellular membranes are complex mixtures of lipids, proteins and other small molecules that provide functional, dynamic barriers between the cell and its environment, as well as between environments within the cell. The lipid composition of the membrane is highly specific and controlled in terms of both content and lipid localization. Here, small-angle neutron scattering and selective deuterium labeling were used to probe the impact of the membrane-active peptides melittin and alamethicin on the structure of lipid bilayers composed of a mixture of the lipids dimyristoyl phosphatidylglycerol (DMPG) and chain-perdeuterated dimyristoyl phosphatidylcholine (DMPC). We found that both peptides enriched the outer leaflet of the bilayer with the negatively charged DMPG, creating an asymmetric distribution of lipids. The level of enrichment is peptide concentration-dependent and is stronger for melittin than alamethicin. The enrichment between the inner and outer bilayer leaflets occurs at very low peptide concentrations, and increases with peptide concentration, including when the peptide adopts a membrane-spanning, pore-forming state.

  4. The distribution of Sr2+ counterions around polyacrylate chains analyzed by anomalous small-angle X-ray scattering

    Science.gov (United States)

    Goerigk, G.; Schweins, R.; Huber, K.; Ballauff, M.

    2004-05-01

    The distribution of Sr counterions around negatively charged sodium polyacrylate chains (NaPA) in aqueous solution was studied by anomalous small-angle X-ray scattering. Different ratios of the concentrations of SrCl2/[NaPA] reveal dramatic changes in the scattering curves. At the lower ratio the scattering curves indicate a coil-like behavior, while at the higher ratio the scattering curves are contracted to smaller q-values, caused by the collapse of the NaPA coil. The form factor of the scattering contribution of the counterions was separated and analyzed. For the scattering curves of the collapsed chains, this analysis agrees with the model of a pearl necklace, consisting of collapsed sphere-like subdomains which are connected by stretched chain segments. An averaged radius of the pearls of 19 nm and a distance between neighbouring pearls close to 60 nm could be established for the collapsed state of the NaPA chains.

  5. Evolution of column density distributions within Orion~A

    CERN Document Server

    Stutz, A M

    2015-01-01

    We compare the structure of star-forming molecular clouds in different regions of Orion A to determine how the column density probability distribution function (N-PDF) varies with environmental conditions such as the fraction of young protostars. A correlation between the N-PDF slope and Class 0 protostar fraction has been previously observed in a low-mass star-formation region (Perseus) by Sadavoy; here we test if a similar correlation is observed in a high-mass star-forming region. We use Herschel data to derive a column density map of Orion A. We use the Herschel Orion Protostar Survey catalog for accurate identification and classification of the Orion A young stellar object (YSO) content, including the short-lived Class 0 protostars (with a $\\sim$ 0.14 Myr lifetime). We divide Orion A into eight independent 13.5 pc$^2$ regions; in each region we fit the N-PDF distribution with a power-law, and we measure the fraction of Class 0 protostars. We use a maximum likelihood method to measure the N-PDF power-law ...

  6. Research on social communication network evolution based on topology potential distribution

    Science.gov (United States)

    Zhao, Dongjie; Jiang, Jian; Li, Deyi; Zhang, Haisu; Chen, Guisheng

    2011-12-01

    Aiming at the problem of social communication network evolution, first, topology potential is introduced to measure the local influence among nodes in networks. Second, from the perspective of topology potential distribution the method of network evolution description based on topology potential distribution is presented, which takes the artificial intelligence with uncertainty as basic theory and local influence among nodes as essentiality. Then, a social communication network is constructed by enron email dataset, the method presented is used to analyze the characteristic of the social communication network evolution and some useful conclusions are got, implying that the method is effective, which shows that topology potential distribution can effectively describe the characteristic of sociology and detect the local changes in social communication network.

  7. Extraction of Quark Transversity Distribution and Collins Fragmentation Functions with QCD Evolution

    CERN Document Server

    Kang, Zhong-Bo; Sun, Peng; Yuan, Feng

    2016-01-01

    We study the transverse momentum dependent (TMD) evolution of the Collins azimuthal asymmetries in $e^+e^-$ annihilations and semi-inclusive hadron production in deep inelastic scattering (SIDIS) processes. All the relevant coefficients are calculated up to the next-to-leading logarithmic (NLL) order accuracy. By applying the TMD evolution at the approximate NLL order in the Collins-Soper-Sterman (CSS) formalism, we extract transversity distributions for $u$ and $d$ quarks and Collins fragmentation functions from current experimental data by a global analysis of the Collins asymmetries in back-to-back di-hadron productions in $e^+e^-$ annihilations measured by BELLE and BABAR Collaborations and SIDIS data from HERMES, COMPASS, and JLab HALL A experiments. The impact of the evolution effects and the relevant theoretical uncertainties are discussed. We further discuss the TMD interpretation for our results, and illustrate the unpolarized quark distribution, transversity distribution, unpolarized quark fragmenta...

  8. Evolution of column density distributions within Orion A⋆

    Science.gov (United States)

    Stutz, A. M.; Kainulainen, J.

    2015-05-01

    We compare the structure of star-forming molecular clouds in different regions of Orion A to determine how the column density probability distribution function (N-PDF) varies with environmental conditions such as the fraction of young protostars. A correlation between the N-PDF slope and Class 0 protostar fraction has been previously observed in a low-mass star-formation region (Perseus); here we test whether a similar correlation is observed in a high-mass star-forming region. We used Herschel PACS and SPIRE cold dust emission observations to derive a column density map of Orion A. We used the Herschel Orion Protostar Survey catalog to accurately identify and classify the Orion A young stellar object content, including the cold and relatively short-lived Class 0 protostars (with a lifetime of ~0.14 Myr). We divided Orion A into eight independent regions of 0.25 square degrees (13.5 pc2); in each region we fit the N-PDF distribution with a power law, and we measured the fraction of Class 0 protostars. We used a maximum-likelihood method to measure the N-PDF power-law index without binning the column density data. We find that the Class 0 fraction is higher in regions with flatter column density distributions. We tested the effects of incompleteness, extinction-driven misclassification of Class 0 sources, resolution, and adopted pixel-scales. We show that these effects cannot account for the observed trend. Our observations demonstrate an association between the slope of the power-law N-PDF and the Class 0 fractions within Orion A. Various interpretations are discussed, including timescales based on the Class 0 protostar fraction assuming a constant star-formation rate. The observed relation suggests that the N-PDF can be related to an evolutionary state of the gas. If universal, such a relation permits evaluating the evolutionary state from the N-PDF power-law index at much greater distances than those accessible with protostar counts. Appendices are available in

  9. Impact of pitch angle setup error and setup error correction on dose distribution in volumetric modulated arc therapy for prostate cancer.

    Science.gov (United States)

    Takemura, Akihiro; Togawa, Kumiko; Yokoi, Tomohiro; Ueda, Shinichi; Noto, Kimiya; Kojima, Hironori; Isomura, Naoki; Kumano, Tomoyasu

    2016-07-01

    In volumetric modulated arc therapy (VMAT) for prostate cancer, a positional and rotational error correction is performed according to the position and angle of the prostate. The correction often involves body leaning, and there is concern regarding variation in the dose distribution. Our purpose in this study was to evaluate the impact of body pitch rotation on the dose distribution regarding VMAT. Treatment plans were obtained retrospectively from eight patients with prostate cancer. The body in the computed tomography images for the original VMAT plan was shifted to create VMAT plans with virtual pitch angle errors of ±1.5° and ±3°. Dose distributions for the tilted plans were recalculated with use of the same beam arrangement as that used for the original VMAT plan. The mean value of the maximum dose differences in the dose distributions between the original VMAT plan and the tilted plans was 2.98 ± 0.96 %. The value of the homogeneity index for the planning target volume (PTV) had an increasing trend according to the pitch angle error, and the values of the D 95 for the PTV and D 2ml, V 50, V 60, and V 70 for the rectum had decreasing trends (p pitch angle error caused by body leaning had little effect on the dose distribution; in contrast, the pitch angle correction reduced the effects of organ displacement and improved these indexes. Thus, the pitch angle setup error in VMAT for prostate cancer should be corrected. PMID:26873139

  10. Model-Independent Evolution of Transverse Momentum Dependent Distribution Functions (TMDs) at NNLL

    CERN Document Server

    Echevarria, Miguel G; Schäfer, Andreas; Scimemi, Ignazio

    2012-01-01

    We present a new approach to treat the perturbative QCD evolution of TMDs by resummation. We obtain a universal evolution kernel for the eight quark distributions while large logarithms are resummed up to next-to-next-to leading logarithms (NNLL). Contrary to earlier works this resummation gives unambiguous predictions avoiding the need to introduce an ad-hoc cut-off parameters and thus highly reducing the model-dependence. Applications to single-spin asymmetries, as the Sivers function, and unpolarized transverse-momentum-dependent parton distribution functions are given. The results agree very well with phenomenology.

  11. The Evolution of the Pion Distribution Amplitude in Next-to-Leading Order

    OpenAIRE

    Müller, Dieter

    1994-01-01

    The evolution of the pion distribution amplitude in next-to-leading order is studied for a fixed and a running coupling constant. In both cases, the evolution provides a logarithmic modification in the endpoint region. Assuming a simple parameterization of the distribution amplitude at a scale of $Q_0\\sim 0.5\\ \\rm GeV$, it is shown numerically that these effects are large enough at $Q\\sim 2\\ \\rm GeV$ that they have to be taken into account in the next-to-leading-order analysis for exclusive p...

  12. Study of local environment and cation distribution in Al(III) oxides by 27Al-NMR with sample rotation at a ''magic'' angle

    International Nuclear Information System (INIS)

    The possible use of the 27Al-NMR method with sample rotation at a ''magic'' angle to study the local environment and cation distribution of Al(III) ions in the oxide lattice are exemplified by γ-, eta-, chi-, α-Al2O3 and commercial A-1 Al(III) oxide. (author)

  13. Solution of nonlinear Gribov-Levin-Ryskin-Mueller-Qiu evolution equation for gluon distribution function

    International Nuclear Information System (INIS)

    In this paper we have determined the behavior of gluon distribution function by solving the Gribov-Levin-Reskin-Mueller-Qiu (GLR-MQ) evolution equation,which is nonlinear in gluon density. The moderate Q2 behavior of G(x, t), where t = ln(Q2/Λ2), is obtained by employing the Regge like behaviour of gluon distribution function at small-x. Here Q2 behavior of nonlinear gluon distribution function is investigated for small values x = 10−2, 10−3, 10−4 and 10−5 rexpectively. Our predictions are compared with different parametrisations and are found in good agreement. It is observed from our results that with the nonlinear corrections incorporated, the strong growth of G(x,t) that corresponds to the linear QCD evolution equation is slowed down. Moreover essential taming of gluon distribution function is observed for R = 2 GeV−1 as expected

  14. Influence of the angle between cold rolling direction and hot rolling direction on the texture evolution of non-oriented electrical steels

    Science.gov (United States)

    He, Y.; Hilinski, E.; Attard, M.; Bibby, D.; Santos, R.; Zavadil, R.

    2015-04-01

    In processing non-oriented electrical steel sheets using conventional rolling schemes, the most common texture components obtained after final annealing are the magnetically unfavourable //ND (γ) and //RD (α) fibres. A lot of researches have been carried out trying to optimize the processes to produce the favourable //ND (θ) fibre. However, since the final texture is formed through a series of texture evolution steps during the solidification, hot rolling, cold rolling and annealing processes, it is quite challenging to tailor the texture of the final product. In this study, a new rolling scheme was examined, in which the cold rolling direction (CRD) was inclined to the hot rolling direction (HRD) at an angle from 0° to 90° (with a 15° increment). This was intended to alter the texture commonly produced by cold rolling along the HRD, and to optimize the final recrystallization texture. The cold rolling and recrystallization textures of two non-oriented electrical steels with 0.9% and 2.8% Si were measured. It was found that the inclination of CRD to HRD has a substantial effect on the cold rolling texture for both steels, but only in the low Si steel, does it lead to significantly different recrystallization textures. A strong cube texture was produced at an inclination angle of 60°, and the //ND (γ) fibre was significantly weakened or essentially disappeared. The core losses of these steels were measured by Epstein frame method and the results showed a ∼10% difference among strips cold rolled at different angles. A minimum core loss occurred at a 45° inclination angle in the low Si steel.

  15. The time-evolution of DCIS size distributions with applications to breast cancer growth and progression

    OpenAIRE

    Dowty, James G.; Byrnes, Graham B; Gertig, Dorota M

    2013-01-01

    Ductal carcinoma {\\em in situ} (DCIS) lesions are non-invasive tumours of the breast which are thought to precede most invasive breast cancers (IBC). As individual DCIS lesions are initiated, grow and invade (i.e. become IBC) the size distribution of the DCIS lesions present in a given human population will evolve. We derive a differential equation governing this evolution and show, for given assumptions about growth and invasion, that there is a unique distribution which does not vary with t...

  16. Academic training: From Evolution Theory to Parallel and Distributed Genetic Programming

    CERN Multimedia

    2007-01-01

    2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 15, 16 March From 11:00 to 12:00 - Main Auditorium, bldg. 500 From Evolution Theory to Parallel and Distributed Genetic Programming F. FERNANDEZ DE VEGA / Univ. of Extremadura, SP Lecture No. 1: From Evolution Theory to Evolutionary Computation Evolutionary computation is a subfield of artificial intelligence (more particularly computational intelligence) involving combinatorial optimization problems, which are based to some degree on the evolution of biological life in the natural world. In this tutorial we will review the source of inspiration for this metaheuristic and its capability for solving problems. We will show the main flavours within the field, and different problems that have been successfully solved employing this kind of techniques. Lecture No. 2: Parallel and Distributed Genetic Programming The successful application of Genetic Programming (GP, one of the available Evolutionary Algorithms) to optimization problems has encouraged an ...

  17. Numerical solution of $Q^{2}$ evolution equation for the transversity distribution $\\Delta_{T}$ q

    CERN Document Server

    Hirai, M; Miyama, M

    1998-01-01

    We investigate numerical solution of the Dokshitzer-Gribov-Lipatov-Altarelli- Parisi (DGLAP) Q^2 evolution equation for the transversity distribution Delta_T q or the structure function h_1. The leading-order (LO) and next-to- leading-order (NLO) evolution equations are studied. The renormalization scheme is MS or overline{MS} in the NLO case. Dividing the variables x and Q^2 into small steps, we solve the integrodifferential equations by the Euler method in the variable Q^2 and by the Simpson method in the variable x. Numerical results indicate that accuracy is better than 1% in the region 10^{-5}evolution and devolution of the transversity distribution Delta_T q or h_1. Using the program, we show the LO and NLO evolution results of the valence-quark distribution Delta_T u_v + Delta_T d_v, the singlet distribution sum_i (Delta_T q_i + Delta_T qbar_i), and the flavor asymmetric dist...

  18. Measurement of the weak mixing angle and the spin of the gluon from angular distributions in the reaction pp→ Z/γ*+X→μ+μ-+X with ATLAS

    International Nuclear Information System (INIS)

    The measurement of the effective weak mixing angle with the ATLAS experiment at the LHC is presented. It is extracted from the forward-backward asymmetry in the polar angle distribution of the muons originating from Z boson decays in the reaction pp→Z/γ*+X→ μ+μ-+X. In total 4.7 fb-1 of proton-proton collisions at √(s)=7 TeV are analysed. In addition, the full polar and azimuthal angular distributions are measured as a function of the transverse momentum of the Z/γ* system and are compared to several simulations as well as recent results obtained in p anti p collisions. Finally, the angular distributions are used to confirm the spin of the gluon using the Lam-Tung relation.

  19. Nucleonic helicity distributions revisited with an emphasis on their evolutions and twists

    Indian Academy of Sciences (India)

    Rajen Kundu

    2014-12-01

    In this work, we uphold and extend the formalism advocated by us more than a decade ago in order to extract information on various distribution functions describing nucleonic helicity structure and calculate a complete set of splitting functions relevant for their quantum chromodynamics (QCD) evolutions using light-front Hamiltonian perturbation theory in light front gauge + = 0. Twist-two structures of the helicity distributions are self-evident in our calculation. Sum rules associated with these helicity distributions are also verified in a frame-independent way.

  20. Regge behaviour of distribution functions and evolution of gluon distribution function in next-to-leading order at low-x

    Indian Academy of Sciences (India)

    U Jamil; J K Sarma

    2008-09-01

    Evolution of gluon distribution function from Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution equation in next-to-leading order (NLO) at low- is presented assuming the Regge behaviour of quark and gluon at this limit. We compare our results of gluon distribution function with MRST2004, GRV98LO and GRV98NLO parametrizations and show the compatibility of Regge behaviour of quark and gluon distribution functions with perturbative quantum chromodynamics (PQCD) at low-.

  1. QCD evolution of naive-time-reversal-odd parton distribution functions

    International Nuclear Information System (INIS)

    We reexamine the derivation of the leading order QCD evolution equations of twist-3 quark-gluon correlation functions, Tq,F(x,x) and Tq,F(σ)(x,x), which are the first transverse-momentum-moment of the naive-time-reversal-odd parton distribution functions - the Sivers and Boer-Mulders function, respectively. The evolution equations were derived by several groups with apparent differences. We identify the sources that are responsible for the differences, and are able to reconcile the results from various groups.

  2. Renormalization-group improved evolution of the meson distribution amplitude at the two-loop level

    International Nuclear Information System (INIS)

    We discuss the two-loop evolution of the flavor-nonsinglet meson distribution amplitude in perturbative QCD. After reviewing previous two-loop computations, we outline the incompatibility of these solutions with the group property of the renormalization-group transformations. To cure this deficiency, we compute a correction factor for the non-diagonal part of the meson evolution equation and prove that with this modification the two-loop solution conforms with the group properties of the renormalization-group transformations. The special case of a fixed strong coupling (no Q2 dependence) is also discussed, and comparison is given to previously obtained results

  3. Determination of the bond-angle distribution in vitreous B2O3 by 11B double rotation (DOR) NMR spectroscopy

    International Nuclear Information System (INIS)

    The B-O-B bond angle distributions for both ring and non-ring boron sites in vitreous B2O3 have been determined by 11B double rotation (DOR) NMR and multiple-quantum (MQ) DOR NMR. The [B3O6] boroxol rings are observed to have a mean internal B-O-B angle of 120.0±0.7 deg. with a small standard deviation, σR=3.2±0.4 deg., indicating that the rings are near-perfect planar, hexagonal structures. The rings are linked predominantly by non-ring [BO3] units, which share oxygens with the boroxol ring, with a mean Bring-O-Bnon-ring angle of 135.1±0.6 deg. and σNR=6.7±0.4 deg. In addition, the fraction of boron atoms, f, which reside in the boroxol rings has been measured for this sample as f=0.73±0.01. - Graphical abstract: Connectivities and B-O-B bond angle distributions of ring and non-ring boron atoms in v-B2O3 have been determined by 11B double rotation (DOR) NMR, multiple-quantum (MQ) DOR NMR and spin-diffusion DOR. Near-perfect planar, hexagonal [B3O6] boroxol rings are shown to be present. Display Omitted

  4. Model independent evolution of transverse momentum dependent distribution functions (TMDs) at NNLL

    Energy Technology Data Exchange (ETDEWEB)

    Echevarria, Miguel G.; Scimemi, Ignazio [Universidad Complutense de Madrid (UCM), Departamento de Fisica Teorica II, Madrid (Spain); Idilbi, Ahmad [European Centre for Theoretical Studies in Nuclear Physics and Related Areas, ECT, Villazzano, Trento (Italy); Schaefer, Andreas [Universitaet Regensburg, Instituet fuer Theoretische Physik, Regensburg (Germany)

    2013-12-15

    We discuss the evolution of the eight leading-twist transverse momentum dependent parton distribution functions, which turns out to be universal and spin independent. By using the highest order perturbatively calculable ingredients at our disposal, we perform the resummation of the large logarithms that appear in the evolution kernel of transverse momentum distributions up to next-to-next-to-leading logarithms (NNLL), thus obtaining an expression for the kernel with highly reduced model dependence. Our results can also be obtained using the standard CSS approach when a particular choice of the b {sup *} prescription is used. In this sense, and while restricted to the perturbative domain of applicability, we consider our results as a ''prediction'' of the correct value of b{sub max} which is very close to 1.5 GeV{sup -1}. We explore under which kinematical conditions the effects of the non-perturbative region are negligible, and hence the evolution of transverse momentum distributions can be applied in a model independent way. The application of the kernel is illustrated by considering the unpolarized transverse momentum dependent parton distribution function and the Sivers function. (orig.)

  5. Model independent evolution of transverse momentum dependent distribution functions (TMDs) at NNLL

    International Nuclear Information System (INIS)

    We discuss the evolution of the eight leading-twist transverse momentum dependent parton distribution functions, which turns out to be universal and spin independent. By using the highest order perturbatively calculable ingredients at our disposal, we perform the resummation of the large logarithms that appear in the evolution kernel of transverse momentum distributions up to next-to-next-to-leading logarithms (NNLL), thus obtaining an expression for the kernel with highly reduced model dependence. Our results can also be obtained using the standard CSS approach when a particular choice of the b * prescription is used. In this sense, and while restricted to the perturbative domain of applicability, we consider our results as a ''prediction'' of the correct value of bmax which is very close to 1.5 GeV-1. We explore under which kinematical conditions the effects of the non-perturbative region are negligible, and hence the evolution of transverse momentum distributions can be applied in a model independent way. The application of the kernel is illustrated by considering the unpolarized transverse momentum dependent parton distribution function and the Sivers function. (orig.)

  6. An investigation of the dose distribution effect related with collimator angle in volumetric arc therapy of prostate cancer

    Directory of Open Access Journals (Sweden)

    Bora Tas

    2016-01-01

    Full Text Available To investigate the dose-volume variations of planning target volume (PTV and organ at risks (OARs in eleven prostate cancer patients planned with single and double arc volumetric modulated arc therapy (VMAT when varying collimator angle. Single and double arc VMAT treatment plans were created using Monaco5.0® with collimator angle set to 0°. All plans were normalized 7600 cGy dose to the 95% of clinical target volume (CTV volume. The single arc VMAT plans were reoptimized with different collimator angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°, and for double arc VMAT plans (0–0°, 15°–345, 30–330°, 45–315°, 60–300°, 75–285°, 90–270° using the same optimization parameters. For the comparison the parameters of heterogeneity index (HI, dose-volume histogram and minimum dose to the 95% of PTV volume (D95 PTV calculated and analyzed. The best plans were verified using 2 dimensional ion chamber array IBA Matrixx® and three-dimensional IBA Compass® program. The comparison between calculation and measurement were made by the γ-index (3%/3 mm analysis. A higher D95 (PTV were found for single arc VMAT with 15° collimator angle. For double arc, VMAT with 60–300° and 75–285° collimator angles. However, lower rectum doses obtained for 75–285° collimator angles. There was no significant dose difference, based on other OARs which are bladder and femur head. When we compared single and double arc VMAT's D95 (PTV, we determined 2.44% high coverage and lower HI with double arc VMAT. All plans passed the γ-index (3%/3 mm analysis with more than 97% of the points and we had an average γ-index for CTV 0.36, for PTV 0.32 with double arc VMAT. These results were significant by Wilcoxon signed rank test statistically. The results show that dose coverage of target and OAR's doses also depend significantly on the collimator angles due to the geometry of target and OARs. Based on the results we have decided to plan prostate

  7. An investigation of the dose distribution effect related with collimator angle in volumetric arc therapy of prostate cancer.

    Science.gov (United States)

    Tas, Bora; Bilge, Hatice; Ozturk, Sibel Tokdemir

    2016-01-01

    To investigate the dose-volume variations of planning target volume (PTV) and organ at risks (OARs) in eleven prostate cancer patients planned with single and double arc volumetric modulated arc therapy (VMAT) when varying collimator angle. Single and double arc VMAT treatment plans were created using Monaco5.0(®) with collimator angle set to 0°. All plans were normalized 7600 cGy dose to the 95% of clinical target volume (CTV) volume. The single arc VMAT plans were reoptimized with different collimator angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°), and for double arc VMAT plans (0-0°, 15°-345, 30-330°, 45-315°, 60-300°, 75-285°, 90-270°) using the same optimization parameters. For the comparison the parameters of heterogeneity index (HI), dose-volume histogram and minimum dose to the 95% of PTV volume (D95 PTV) calculated and analyzed. The best plans were verified using 2 dimensional ion chamber array IBA Matrixx(®) and three-dimensional IBA Compass(®) program. The comparison between calculation and measurement were made by the γ-index (3%/3 mm) analysis. A higher D95 (PTV) were found for single arc VMAT with 15° collimator angle. For double arc, VMAT with 60-300° and 75-285° collimator angles. However, lower rectum doses obtained for 75-285° collimator angles. There was no significant dose difference, based on other OARs which are bladder and femur head. When we compared single and double arc VMAT's D95 (PTV), we determined 2.44% high coverage and lower HI with double arc VMAT. All plans passed the γ-index (3%/3 mm) analysis with more than 97% of the points and we had an average γ-index for CTV 0.36, for PTV 0.32 with double arc VMAT. These results were significant by Wilcoxon signed rank test statistically. The results show that dose coverage of target and OAR's doses also depend significantly on the collimator angles due to the geometry of target and OARs. Based on the results we have decided to plan prostate cancer patients in our

  8. Influence of anisotropic grain boundary properties on the evolution of grain boundary character distribution during grain growth—a 2D level set study

    International Nuclear Information System (INIS)

    The present study elaborates on a 2D level set model of polycrystal microstructures that was recently established by adding the influence of anisotropic grain boundary energy and mobility on microstructure evolution. The new model is used to trace the evolution of grain boundary character distribution during grain growth. The employed level set formulation conveniently allows the grain boundary characteristics to be quantified in terms of coincidence site lattice (CSL) type per unit of grain boundary length, providing a measure of the distribution of such boundaries. In the model, both the mobility and energy of the grain boundaries are allowed to vary with misorientation. In addition, the influence of initial polycrystal texture is studied by comparing results obtained from a polycrystal with random initial texture against results from a polycrystal that initially has a cube texture. It is shown that the proposed level set formulation can readily incorporate anisotropic grain boundary properties and the simulation results further show that anisotropic grain boundary properties only have a minor influence on the evolution of CSL boundary distribution during grain growth. As anisotropic boundary properties are considered, the most prominent changes in the CSL distributions are an increase of general low-angle Σ1 boundaries as well as a more stable presence of Σ3 boundaries. The observations also hold for the case of an initially cube-textured polycrystal. The presence of this kind of texture has little influence over the evolution of the CSL distribution. Taking into consideration the anisotropy of grain boundary properties, grain growth alone does not seem to be sufficient to promote any significantly increased overall presence of CSL boundaries. (paper)

  9. Small-angle X-ray scattering study of the structural evolution of the drying of teos-derived sonogels with the liquid phase exchanged by acetone

    International Nuclear Information System (INIS)

    Full text: The structural evolution on the drying of wet sonogels of silica with the liquid phase exchanged by acetone, obtained from tetraethoxisilane sonohydrolysis, was studied 'in situ' by small-angle X-ray scattering (SAXS). The SAXS measurements were carried out using synchrotron radiation with a wavelength λ = 0.1608 nm and a pin-hole geometry collimated beam. The periods associated to the structural evolution as determined by SAXS are in agreement with those classical ones established on basis of the features of the evaporation rate of the liquid phase in the obtaining of xerogels. The SAXS data were analyzed on basis of the fractal characteristics of the sonogels. The wet gel can be described as formed by primary particles (microclusters), with characteristic length a ∼ 0.67 nm and surface which is fractal, linking together to form mass fractal structures with mass fractal dimension D = 2.24 in a length scale ξ ∼ 6.7 nm. As the network collapses while the liquid/vapor meniscus is kept out of the gel volume, the mass fractal structure becomes more compacted by increasing D and decreasing ξ, with smoothing of the fractal surface of the microclusters. The time evolution of the density of the wet gels was evaluated exclusively from the SAXS parameters ξ, D and a. The final dried acetone-exchanged gel presents Porod's inhomogeneity length of about 2.8 nm and apparently exhibits an interesting singularity D → 3, as determined by the mass fractal modeling used to t the SAXS intensity data for the obtaining of the parameters ξ and D. (author)

  10. Three-dimensional distribution and evolution of permafrost temperatures in idealized high-mountain topography

    OpenAIRE

    Noetzli, J.; Gruber, S.; Kohl, T; Salzmann, N.; Haeberli, W.

    2007-01-01

    Permafrost degradation is regarded as a crucial factor influencing the stability of steep rockwalls in alpine areas. Discernment of zones of fast temperature changes requires knowledge about the temperature distribution and evolution at and below the surface of steep rock. In complex high-mountain topography, strong lateral heat fluxes result from topography and variable surface temperatures and profoundly influence the subsurface thermal field. To investigate such three-dimensional effects, ...

  11. The Evolution of US City Size Distribution from a Long Term Perspective (1900-2000)

    OpenAIRE

    González-Val, Rafael

    2009-01-01

    This paper analyses the evolution of city size distribution in the United States throughout the twentieth century. In particular, it tests the validity of two empirical regularities studied in urban economics: Zipf’s law, which postulates that the product between rank and size of a population is constant, and Gibrat’s law or the law of proportionate growth, according to which the growth rate of a variable is independent of its initial size. To achieve this, we use parametric and nonparametric...

  12. On a link between a species survival time in an evolution model and the Bessel distributions

    CERN Document Server

    Guiol, Herve; Schinazi, Rinaldo B

    2011-01-01

    We consider a stochastic model for species evolution. A new species is born at rate lambda and a species dies at rate mu. A random number, sampled from a given distribution F, is associated with each new species at the time of birth. Every time there is a death event, the species that is killed is the one with the smallest fitness. We consider the (random) survival time of a species with a given fitness f. We show that the survival time distribution depends crucially on whether ff_c where f_c is a critical fitness that is computed explicitly.

  13. Time evolution of the lateral-velocity distribution for a strong-field-ionization process

    Science.gov (United States)

    Ivanov, I. A.

    2016-05-01

    We study time development of a cusp in the lateral-velocity distribution for the process of strong-field ionization. The lateral-velocity distribution is computed using an ab initio quantum mechanical procedure for the moments of time inside and after the end of the laser pulse. We show that at the moment of time corresponding to the midpoint of the laser pulse the lateral-velocity distribution is a smooth Gaussian curve, its parameters agreeing very well with the predictions of the tunelling theories. At the moment of time corresponding to the end of the pulse the lateral-velocity distribution narrows considerably, showing the initial stage of the cusp-formation process due to the Coulomb focusing effect. Following evolution of the ionized wave packet yet further in time we consider the cusp formation in detail.

  14. Nonlinear evolution of the electromagnetic electron-cyclotron instability in bi-Kappa distributed plasma

    Energy Technology Data Exchange (ETDEWEB)

    Eliasson, B., E-mail: bengt.eliasson@strath.ac.uk [SUPA, Physics Department, John Anderson Building, Strathclyde University, Glasgow G4 0NG, Scotland (United Kingdom); Lazar, M., E-mail: mlazar@tp4.rub.de [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Leuven (Belgium); Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, 44780 Bochum (Germany)

    2015-06-15

    This paper presents a numerical study of the linear and nonlinear evolution of the electromagnetic electron-cyclotron (EMEC) instability in a bi-Kappa distributed plasma. Distributions with high energy tails described by the Kappa power-laws are often observed in collision-less plasmas (e.g., solar wind and accelerators), where wave-particle interactions control the plasma thermodynamics and keep the particle distributions out of Maxwellian equilibrium. Under certain conditions, the anisotropic bi-Kappa distribution gives rise to plasma instabilities creating low-frequency EMEC waves in the whistler branch. The instability saturates nonlinearly by reducing the temperature anisotropy until marginal stability is reached. Numerical simulations of the Vlasov-Maxwell system of equations show excellent agreement with the growth-rate and real frequency of the unstable modes predicted by linear theory. The wave-amplitude of the EMEC waves at nonlinear saturation is consistent with magnetic trapping of the electrons.

  15. NLO $Q^{2}$-evolution of the nucleon's transversity distribution $h_{1}(x, Q^2)$

    CERN Document Server

    Hayashigaki, A; Koike, Y; Koike, Yuji

    1997-01-01

    We present a calculation of the two-loop anomalous dimension for the transversity distribution $h_1(x,Q^2)$, $\\gamma^{h(1)}_n$, in the MS scheme of the dimensional regularization. Because of the chiral-odd nature, $h_1$ does not mix with the gluon distributions, and thus our result is the same for the flavor-singlet and nonsinglet distributions. At small $n$ (moment of $h_1$), anomalous dimension for the nonsinglet $f_1$ and $g_1$), but approaches relation between the one-loop anomalous dimension for $f_1$ $(g_1)$ and $h_1$. We also show that this difference in the anomalous dimension between $h_1$ and $g_1$ leads to a drastic difference in the $Q^2$-evolution of those distributions in the small $x$ region.

  16. Reliability Optimization of Radial Distribution Systems Employing Differential Evolution and Bare Bones Particle Swarm Optimization

    Science.gov (United States)

    Kela, K. B.; Arya, L. D.

    2014-09-01

    This paper describes a methodology for determination of optimum failure rate and repair time for each section of a radial distribution system. An objective function in terms of reliability indices and their target values is selected. These indices depend mainly on failure rate and repair time of a section present in a distribution network. A cost is associated with the modification of failure rate and repair time. Hence the objective function is optimized subject to failure rate and repair time of each section of the distribution network considering the total budget allocated to achieve the task. The problem has been solved using differential evolution and bare bones particle swarm optimization. The algorithm has been implemented on a sample radial distribution system.

  17. DSTATCOM allocation in distribution networks considering reconfiguration using differential evolution algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Jazebi, S., E-mail: jazebi@aut.ac.i [Dept. of Electrical Engineering, Amirkabir University of Technology, No. 424, Hafez Avenue, Tehran 158754413 (Iran, Islamic Republic of); Hosseinian, S.H., E-mail: hosseinian@aut.ac.i [Dept. of Electrical Engineering, Amirkabir University of Technology, No. 424, Hafez Avenue, Tehran 158754413 (Iran, Islamic Republic of); Vahidi, B., E-mail: vahidi@aut.ac.i [Dept. of Electrical Engineering, Amirkabir University of Technology, No. 424, Hafez Avenue, Tehran 158754413 (Iran, Islamic Republic of)

    2011-07-15

    Highlights: {yields} Reconfiguration and DSTATCOM allocation are implemented for RDS planning. {yields} Differential evolution algorithm is applied to solve the nonlinear problem. {yields} Optimal status of tie switches, DSTATCOM size and location are determined. {yields} The goal is to minimize network losses and to improve voltage profile. {yields} The results show the effectiveness of the proposed method to satisfy objectives. -- Abstract: The main idea in distribution network reconfiguration is usually to reduce loss by changing the status of sectionalizing switches and determining appropriate tie switches. Recently Distribution FACTS (DFACTS) devices such as DSTATCOM also have been planned for loss reduction and voltage profile improvement in steady state conditions. This paper implements a combinatorial process based on reconfiguration and DSTATCOM allocation in order to mitigate losses and improve voltage profile in power distribution networks. The distribution system tie switches, DSTATCOM location and size have been optimally determined to obtain an appropriate operational condition. Differential evolution algorithm (DEA) has been used to solve and overcome the complicity of this combinatorial nonlinear optimization problem. To validate the accuracy of results a comparison with particle swarm optimization (PSO) has been made. Simulations have been applied on 69 and 83 busses distribution test systems. All optimization results show the effectiveness of the combinatorial approach in loss reduction and voltage profile improvement.

  18. DSTATCOM allocation in distribution networks considering reconfiguration using differential evolution algorithm

    International Nuclear Information System (INIS)

    Highlights: → Reconfiguration and DSTATCOM allocation are implemented for RDS planning. → Differential evolution algorithm is applied to solve the nonlinear problem. → Optimal status of tie switches, DSTATCOM size and location are determined. → The goal is to minimize network losses and to improve voltage profile. → The results show the effectiveness of the proposed method to satisfy objectives. -- Abstract: The main idea in distribution network reconfiguration is usually to reduce loss by changing the status of sectionalizing switches and determining appropriate tie switches. Recently Distribution FACTS (DFACTS) devices such as DSTATCOM also have been planned for loss reduction and voltage profile improvement in steady state conditions. This paper implements a combinatorial process based on reconfiguration and DSTATCOM allocation in order to mitigate losses and improve voltage profile in power distribution networks. The distribution system tie switches, DSTATCOM location and size have been optimally determined to obtain an appropriate operational condition. Differential evolution algorithm (DEA) has been used to solve and overcome the complicity of this combinatorial nonlinear optimization problem. To validate the accuracy of results a comparison with particle swarm optimization (PSO) has been made. Simulations have been applied on 69 and 83 busses distribution test systems. All optimization results show the effectiveness of the combinatorial approach in loss reduction and voltage profile improvement.

  19. Extraction of quark transversity distribution and Collins fragmentation functions with QCD evolution

    Science.gov (United States)

    Kang, Zhong-Bo; Prokudin, Alexei; Sun, Peng; Yuan, Feng

    2016-01-01

    We study the transverse-momentum-dependent (TMD) evolution of the Collins azimuthal asymmetries in e+e- annihilations and semi-inclusive hadron production in deep inelastic scattering processes. All the relevant coefficients are calculated up to the next-to-leading-logarithmic-order accuracy. By applying the TMD evolution at the approximate next-to-leading-logarithmic order in the Collins-Soper-Sterman formalism, we extract transversity distributions for u and d quarks and Collins fragmentation functions from current experimental data by a global analysis of the Collins asymmetries in back-to-back dihadron productions in e+e- annihilations measured by BELLE and BABAR collaborations and semi-inclusive hadron production in deep inelastic scattering data from HERMES, COMPASS, and JLab HALL A experiments. The impact of the evolution effects and the relevant theoretical uncertainties are discussed. We further discuss the TMD interpretation for our results and illustrate the unpolarized quark distribution, transversity distribution, unpolarized quark fragmentation, and Collins fragmentation functions depending on the transverse momentum and the hard momentum scale. We make detailed predictions for future experiments and discuss their impact.

  20. Angular and lateral distributions from small angle multiple scattering including elastic and inelastic energy loss effects based on the Valdes and Arista model

    Energy Technology Data Exchange (ETDEWEB)

    Ikegami, Seiji, E-mail: double1892@gmail.com

    2013-12-01

    The aims of this work are to compare and to include two energy loss effects in multiple scattering caused by elastic and inelastic collisions in angular and lateral distributions based on Valdes and Arista (VA) theory. VA developed small angle multiple scattering theory including energy loss effects based on the Sigmund and Winterbon model for the first time. However, the energy loss effects on lateral distributions have not yet been estimated. In the VA model, target thickness and energy loss are independently treated. In this study, those effects are successfully introduced on the basis of the VA model. We considered the lateral spread and angular distribution separately and included the nuclear and electronic energy loss effects as a function of target thickness. Our results indicate that discrepancies occur between the two distributions, including nuclear and electronic stopping for several target thickness. Moreover, we constructed a multiple scattering model that includes both elastic and inelastic energy losses.

  1. Size Evolution and Stochastic Models: Explaining Ostracod Size through Probabilistic Distributions

    Science.gov (United States)

    Krawczyk, M.; Decker, S.; Heim, N. A.; Payne, J.

    2014-12-01

    The biovolume of animals has functioned as an important benchmark for measuring evolution throughout geologic time. In our project, we examined the observed average body size of ostracods over time in order to understand the mechanism of size evolution in these marine organisms. The body size of ostracods has varied since the beginning of the Ordovician, where the first true ostracods appeared. We created a stochastic branching model to create possible evolutionary trees of ostracod size. Using stratigraphic ranges for ostracods compiled from over 750 genera in the Treatise on Invertebrate Paleontology, we calculated overall speciation and extinction rates for our model. At each timestep in our model, new lineages can evolve or existing lineages can become extinct. Newly evolved lineages are assigned sizes based on their parent genera. We parameterized our model to generate neutral and directional changes in ostracod size to compare with the observed data. New sizes were chosen via a normal distribution, and the neutral model selected new sizes differentials centered on zero, allowing for an equal chance of larger or smaller ostracods at each speciation. Conversely, the directional model centered the distribution on a negative value, giving a larger chance of smaller ostracods. Our data strongly suggests that the overall direction of ostracod evolution has been following a model that directionally pushes mean ostracod size down, shying away from a neutral model. Our model was able to match the magnitude of size decrease. Our models had a constant linear decrease while the actual data had a much more rapid initial rate followed by a constant size. The nuance of the observed trends ultimately suggests a more complex method of size evolution. In conclusion, probabilistic methods can provide valuable insight into possible evolutionary mechanisms determining size evolution in ostracods.

  2. Characterization of the energy distribution of neutrons generated by 5 MeV protons on a thick beryllium target at different emission angles

    International Nuclear Information System (INIS)

    Neutron energy spectra at different emission angles, between 0° and 120° from the Be(p,xn) reaction generated by a beryllium thick-target bombarded with 5 MeV protons, have been measured at the Legnaro Laboratories (LNL) of the Italian National Institute for Nuclear Physics research (INFN). A new and quite compact recoil-proton spectrometer, based on a monolithic silicon telescope, coupled to a polyethylene converter, was efficiently used with respect to the traditional Time-of-Flight (TOF) technique. The measured distributions of recoil-protons were processed through an iterative unfolding algorithm in order to determine the neutron energy spectra at all the angles accounted for. The neutron energy spectrum measured at 0° resulted to be in good agreement with the only one so far available at the requested energy and measured years ago with TOF technique. Moreover, the results obtained at different emission angles resulted to be consistent with detailed past measurements performed at 4 MeV protons at the same angles by TOF techniques.

  3. Characterization of the energy distribution of neutrons generated by 5 MeV protons on a thick beryllium target at different emission angles

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S. [Politecnico di Milano, Dipartimento di Energia, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)] [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Colautti, P., E-mail: paolo.colautti@lnl.infn.it [INFN, Laboratori Nazionali di Legnaro (LNL), Via dell' Universita, 2, I-35020 Legnaro (PD) (Italy); Esposito, J., E-mail: juan.esposito@tin.it [INFN, Laboratori Nazionali di Legnaro (LNL), Via dell' Universita, 2, I-35020 Legnaro (PD) (Italy); Fazzi, A.; Introini, M.V.; Pola, A. [Politecnico di Milano, Dipartimento di Energia, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)] [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milano (Italy)

    2011-12-15

    Neutron energy spectra at different emission angles, between 0 Degree-Sign and 120 Degree-Sign from the Be(p,xn) reaction generated by a beryllium thick-target bombarded with 5 MeV protons, have been measured at the Legnaro Laboratories (LNL) of the Italian National Institute for Nuclear Physics research (INFN). A new and quite compact recoil-proton spectrometer, based on a monolithic silicon telescope, coupled to a polyethylene converter, was efficiently used with respect to the traditional Time-of-Flight (TOF) technique. The measured distributions of recoil-protons were processed through an iterative unfolding algorithm in order to determine the neutron energy spectra at all the angles accounted for. The neutron energy spectrum measured at 0 Degree-Sign resulted to be in good agreement with the only one so far available at the requested energy and measured years ago with TOF technique. Moreover, the results obtained at different emission angles resulted to be consistent with detailed past measurements performed at 4 MeV protons at the same angles by TOF techniques.

  4. Time-Evolution of a Fractal Distribution: Particle Concentrations in Free-Surface Turbulence

    CERN Document Server

    Larkin, Jason; Bandi, M M

    2010-01-01

    Steady-state turbulence is generated in a tank of water and the trajectories of particles forming a compressible system on the surface are tracked in time. The initial uniformly distributed floating particles coagulate and form a fractal distribution, a rare manifestation of a fractal object observable in real-space. The surface pattern reaches a steady state in approximately 1 s. Measurements are made of the fractal dimensions $D_q(t)$ ($q=1$ to $6$) of the floating particles starting with the uniform distribution $D_q(0)$ = 2 for Taylor Microscale Reynolds number $Re_{\\lambda} \\simeq 160$. Focus is on the the time-evolution of the correlation dimension $D_2(t)$ as the steady state is approached. This steady state is reached in several large eddy turnover times and does so at an exponential rate.

  5. $Q^2$ evolution of chiral-odd twist-3 distribution $e(x,Q^2)$

    CERN Document Server

    Koike, Y; Koike, Yuji

    1997-01-01

    We study the $Q^2$ dependence of the chiral-odd twist-3 distribution $e(x,Q^2)$.The anomalous dimension matrix for the corresponding twist-3 operators is calculated in the one-loop level. This study completes the calculation of the anomalous dimension matrices for all the twist-3 distributions together with the known results for the other twist-3 distributions $g_2(x,Q^2)$ and $h_L(x,Q^2)$. We also have confirmed that in the large $N_c$ limit the $Q^2$-evolution of $e(x,Q^2)$ is wholely governed by the lowest eigenvalue of the anomalous dimension matrix which takes a very simple analytic form as in the case of $g_2$ and $h_L$.

  6. Variability of the pitch angle distribution of radiation belt ultrarelativistic electrons during and following intense geomagnetic storms: Van Allen Probes observations

    Science.gov (United States)

    Zou, Z.; Ni, B.; Gu, X.; Zhao, Z.; Zhou, C.

    2015-12-01

    Fifteen month of pitch angle resolved Van Allen Probes Relativistic Electron-Proton Telescope (REPT) measurements of differential electron flux are analyzed to investigate the characteristics of the pitch angle distribution of radiation belt ultrarelativistic(> 2 MeV) electrons during storm conditions and during the long-storm decay. By modeling the ultrarelativistic electron pitch angle distribution as ,where is the equatorial pitch angle we examine the spatiotemporal variations of n value. The results show that in general n values increases with the level of geomagnetic activity. In principle the ultrarelativistic electrons respond to geomagnetic storms by becoming peaked at 90° pitch angle with n-values of 2 - 3 as a supportive signature of chorus acceleration outside the plasmasphere. High n-values also exists inside the plasmasphere, being localized adjacent to the plasmapause and energy dependent, which suggests a significant contribution from electronmagnetic ion cyclotron (EMIC) waves scattering. During quiet periods, n values generally evolve to become small, i.e., 0-1. The slow and long-term decays of the ultrarelativistic electrons after geomagnetic storms, while prominent, produce energy and L-shell-dependent decay time scales in association with the solar and geomagnetic activity and wave-particle interaction processes. At lower L shells inside the plasmasphere, the decay time scales for electrons at REPT energies are generally larger, varying from tens of days to hundreds of days, which can be mainly attributed to the combined effect of hiss-induced pitch angle scattering and inward radial diffusion. As L shell increases to L~3.5, a narrow region exists (with a width of ~0.5 L), where the observed ultrarelativistic electrons decay fastest, possibly resulting from efficient EMIC wave scattering. As L shell continues to increase, generally becomes larger again, indicating an overall slower loss process by waves at high L shells. Our investigation based

  7. Characterization of a particle size distribution in a Ni-C granular thin film by grazing incidence small-angle X-ray scattering

    International Nuclear Information System (INIS)

    A grazing incidence small-angle X-ray scattering (GISAXS) technique has been applied for characterizing a particle size distribution of nickel nano-particles in a nickel-carbon granular (Ni-C granular) film fabricated by a cosputtering method on a silicon substrate. The particles were modelled as a spherical shape in order to calculate scattering intensity, and a Γ-distribution was employed for determining the size distribution. In addition, a grazing incidence X-ray diffraction (GIXRD) was also measured in order to determine crystallite size of the particles. The crystallite size was analyzed by the Sherrer equation. The average particle size and the crystallite size are 5.7 and 5.2 nm respectively. These results suggest most of nickel particles are single crystal

  8. The Evolution of the Water Distribution in a Viscous Protoplanetary Disk

    CERN Document Server

    Ciesla, F J; Ciesla, Fred J.; Cuzzi, Jeffrey N.

    2005-01-01

    (Abridged) Astronomical observations have shown that protoplanetary disks are dynamic objects through which mass is transported and accreted by the central star. Age dating of meteorite constituents shows that their creation, evolution, and accumulation occupied several Myr, and over this time disk properties would evolve significantly. Moreover, on this timescale, solid particles decouple from the gas in the disk and their evolution follows a different path. Here we present a model which tracks how the distribution of water changes in an evolving disk as the water-bearing species experience condensation, accretion, transport, collisional destruction, and vaporization. Because solids are transported in a disk at different rates depending on their sizes, the motions will lead to water being concentrated in some regions of a disk and depleted in others. These enhancements and depletions are consistent with the conditions needed to explain some aspects of the chemistry of chondritic meteorites and formation of g...

  9. Integrating evolution into geographical ecology: a phylogenetic perspective on palm distributions and community composition across scales

    DEFF Research Database (Denmark)

    Eiserhardt, Wolf L.; Svenning, J.-C.; Kissling, W. Daniel;

    Species distributions, assemblage composition, and species richness depend on both current environment and the diversification of lineages in past environments. On broad scales, processes that constrain diversifying lineages to certain regions or environments are particularly important. Through s...... of Amazonian palm communities, which mainly reflects the evolution of habitat preferences....... species pool effects, those processes also affect local community composition and richness. In addition, evolution directly affects local communities directly via niche-based assembly. We studied these effects with palms (Arecaceae) as a model group, using a) a dataset including >340,000 palm individuals...... in 430 transects in the Western Amazon, b) a set of range maps for all American palms (550 spp.), and c) global country-level presence/ absence data of all (>2400) palm species. These data were analysed with novel phylogenetic community structure and turnover methods. Globally, the phylogenetic...

  10. The effect of particle size distributions on the microstructural evolution during sintering

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Tikare, V.; Frandsen, Henrik Lund;

    2013-01-01

    Microstructural evolution and sintering behavior of powder compacts composed of spherical particles with different particle size distributions (PSDs) were simulated using a kinetic Monte Carlo model of solid state sintering. Compacts of monosized particles, normal PSDs with fixed mean particle...... PSDs, but the final grain sizes were smaller. These behaviors are explained by the smallest grains in the broader PSDs being consumed very quickly by larger neighboring grains. The elimination of the small grains reduces both the total number of necks and the neck area between particles, which in turn...... reduces the regions where vacancies can be annihilated, leading to slower densification rates. The loss of neck area causes grain growth by surface diffusion to become the dominant microstructural evolution mechanism, leading to poor densification. Finally, pore size was shown to increase with the width...

  11. Asteroid age distributions determined by space weathering and collisional evolution models

    CERN Document Server

    Willman, Mark; 10.1016/j.icarus.2010.02.017

    2010-01-01

    We provide evidence of consistency between the dynamical evolution of main belt asteroids and their color evolution due to space weathering. The dynamical age of an asteroid's surface \\citep{bib.bot05a,bib.nes05} is the time since its last catastrophic disruption event which is a function of the object's diameter. The age of an S-complex asteroid's surface may also be determined from its color using a space weathering model \\citep[e.g.][]{bib.wil10,bib.jed04,bib.wil08,bib.mar06}. We used a sample of 95 S-complex asteroids from SMASS and obtained their absolute magnitudes and $u,g,r,i,z$ filter magnitudes from SDSS. The absolute magnitudes yield a size-derived age distribution. The $u,g,r,i,z$ filter magnitudes lead to the principal component color which yields a color-derived age distribution by inverting our color-age relationship, an enhanced version of the `dual $\\tau$' space weathering model of \\citet{bib.wil10}. We fit the size-age distribution to the enhanced dual $\\tau$ model and found characteristic w...

  12. Cooperative co-evolution based distributed path planning of multiple mobile robots

    Institute of Scientific and Technical Information of China (English)

    WANG Mei; WU Tie-jun

    2005-01-01

    This paper proposes novel multiple-mobile-robot collision avoidance path planning based on cooperative co-evolution,which can be executed fully distributed and in parallel. A real valued co-evolutionary algorithm is developed to coordinate the movement of multiple robots in 2D world, avoiding C-space or grid net searching. The collision avoidance is achieved by cooperatively co-evolving segments of paths and the time interval to pass them. Methods for constraint handling, which are developed for evolutionary algorithm, make the path planning easier. The effectiveness of the algorithm is demonstrated on a number of 2Dpath planning problems.

  13. MERA: a webserver for evaluating backbone torsion angle distributions in dynamic and disordered proteins from NMR data

    Energy Technology Data Exchange (ETDEWEB)

    Mantsyzov, Alexey B. [M.V. Lomonosov Moscow State University, Faculty of Fundamental Medicine (Russian Federation); Shen, Yang; Lee, Jung Ho [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Hummer, Gerhard [Max Planck Institute of Biophysics (Germany); Bax, Ad, E-mail: bax@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2015-09-15

    MERA (Maximum Entropy Ramachandran map Analysis from NMR data) is a new webserver that generates residue-by-residue Ramachandran map distributions for disordered proteins or disordered regions in proteins on the basis of experimental NMR parameters. As input data, the program currently utilizes up to 12 different parameters. These include three different types of short-range NOEs, three types of backbone chemical shifts ({sup 15}N, {sup 13}C{sup α}, and {sup 13}C′), six types of J couplings ({sup 3}J{sub HNHα}, {sup 3}J{sub C′C′}, {sup 3}J{sub C′Hα}, {sup 1}J{sub HαCα}, {sup 2}J{sub CαN} and {sup 1}J{sub CαN}), as well as the {sup 15}N-relaxation derived J(0) spectral density. The Ramachandran map distributions are reported in terms of populations of their 15° × 15° voxels, and an adjustable maximum entropy weight factor is available to ensure that the obtained distributions will not deviate more from a newly derived coil library distribution than required to account for the experimental data. MERA output includes the agreement between each input parameter and its distribution-derived value. As an application, we demonstrate performance of the program for several residues in the intrinsically disordered protein α-synuclein, as well as for several static and dynamic residues in the folded protein GB3.

  14. MERA: a webserver for evaluating backbone torsion angle distributions in dynamic and disordered proteins from NMR data

    International Nuclear Information System (INIS)

    MERA (Maximum Entropy Ramachandran map Analysis from NMR data) is a new webserver that generates residue-by-residue Ramachandran map distributions for disordered proteins or disordered regions in proteins on the basis of experimental NMR parameters. As input data, the program currently utilizes up to 12 different parameters. These include three different types of short-range NOEs, three types of backbone chemical shifts (15N, 13Cα, and 13C′), six types of J couplings (3JHNHα, 3JC′C′, 3JC′Hα, 1JHαCα, 2JCαN and 1JCαN), as well as the 15N-relaxation derived J(0) spectral density. The Ramachandran map distributions are reported in terms of populations of their 15° × 15° voxels, and an adjustable maximum entropy weight factor is available to ensure that the obtained distributions will not deviate more from a newly derived coil library distribution than required to account for the experimental data. MERA output includes the agreement between each input parameter and its distribution-derived value. As an application, we demonstrate performance of the program for several residues in the intrinsically disordered protein α-synuclein, as well as for several static and dynamic residues in the folded protein GB3

  15. Challenging measurement of the {sup 16}O+{sup 27}Al elastic and inelastic angular distributions up to large angles

    Energy Technology Data Exchange (ETDEWEB)

    Cavallaro, M., E-mail: manuela.cavallaro@lns.infn.it [INFN, Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania (Italy); Cappuzzello, F.; Carbone, D.; Cunsolo, A. [INFN, Laboratori Nazionali del Sud, Via S. Sofia 62, I-95125 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95125 Catania (Italy); Foti, A. [Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, I-95125 Catania (Italy); INFN, Sezione di Catania, Via S. Sofia 64, I-95125 Catania (Italy); Linares, R. [Instituto de Fisica, Universidade Federal Fluminense, Litoranea s/n, Gragoata, Niteroi, Rio de Janeiro 24210-340 (Brazil); Pereira, D.; Oliveira, J.R.B.; Gomes, P.R.S.; Lubian, J. [Universidade de Sao Paulo, Departamento de Fisica Nuclear, Instituto de Fisica da Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo, SP (Brazil); Chen, R. [Institute of Modern Physics, CAS, Lanzhou (China)

    2011-08-21

    The {sup 16}O+{sup 27}Al elastic and inelastic angular distributions have been measured in a broad angular range (13{sup o}<{theta}{sub lab}<52{sup o}) at about 100 MeV incident energy. The use of the MAGNEX large acceptance magnetic spectrometer and of the ray-reconstruction analysis technique has been crucial in order to provide, in the same experiment, high-resolution energy spectra and cross-section measurements distributed over more than seven orders of magnitude down to hundreds of nb/sr.

  16. Optimal Capacitor Placement in Radial Distribution Feeders Using Fuzzy-Differential Evolution for Dynamic Load Condition

    Science.gov (United States)

    Kannan, S. M.; Renuga, P.; Kalyani, S.; Muthukumaran, E.

    2015-12-01

    This paper proposes new methods to select the optimal values of fixed and switched shunt capacitors in Radial distribution feeders for varying load conditions so as to maximize the annual savings and minimizes the energy loss by taking the capacitor cost into account. The identification of the weak buses, where the capacitors should be placed is decided by a set of rules given by the fuzzy expert system. Then the sizing of the fixed and switched capacitors is modeled using differential evolution (DE) and particle swarm optimization (PSO). A case study with an existing 15 bus rural distribution feeder is presented to illustrate the applicability of the algorithm. Simulation results show the better saving in cost over previous capacitor placement algorithm.

  17. Information Measure for Size Distribution of Avalanches in the Bak-Sneppen Evolution Model

    Science.gov (United States)

    Li, Wei; Cai, Xu

    2003-01-01

    Information of avalanche size distribution is measured by calculating information entropy (IE) in the Bak-Sneppen evolution model. It is found that the IE increases as the model evolves. Specifically, we establish the relation between the IE and the self-organized threshold fc. The variation of the IE near the critical point yields an exponent entropy index E = (tau-1)/sigma, where tau and sigma represent the critical exponents for avalanche size distribution and avalanche size cutoff, respectively. A new quantity Dtau(g) (g = 1-(fc-G)(tau-1)/sigma, where G is the gap of the current state), defined as 1-Itau(g)/Itau(1), with Itau(g) and Itau(1) being the IE for the current state and the critical one respectively, is suggested that it represents the distance between the state with gap G and the critical one.

  18. Information Measure for Size Distribution of Avalanches in the Bak-Sneppen Evolution Model

    Institute of Scientific and Technical Information of China (English)

    LI Wei; CAI Xu

    2003-01-01

    Information of avalanche size distribution is measured by calculating information entropy (IE) in the Bak-Sneppen evolution model. It is found that the IE increases as the model evolves. Specifically, we establish the relation between the IE and the self-organized threshold fc ? The variation of the IE near the critical point yields an exponent entropy index E = (T - l)/distribution and avalanche size cutoff, respectively. A new quantity DT(g) (g = 1 - (fc - G)'r-1' , where G is the gap of the current state), denned as 1 - IT(g)/IT(l), with IT(g) and /T(l) being the IE for the current state and the critical one respectively, is suggested that it represents the distance between the state with gap G and the critical one.

  19. The Evolution-Dominated Hydrodynamic Model and the Pseudorapidity Distributions in High Energy Physics

    International Nuclear Information System (INIS)

    By taking into account the effects of leading particles, we discuss the pseudorapidity distributions of the charged particles produced in high energy heavy ion collisions in the context of evolution-dominated hydrodynamic model. The leading particles are supposed to have a Gaussian rapidity distribution normalized to the number of participants. A comparison is made between the theoretical results and the experimental measurements performed by BRAHMS and PHOBOS Collaboration at BNL-RHIC in Au-Au and Cu-Cu collisions at √(sNN)=200 GeV and by ALICE Collaboration at CERN-LHC in Pb-Pb collisions at √(sNN)=2.76 TeV

  20. Optimal Location and Sizing of UPQC in Distribution Networks Using Differential Evolution Algorithm

    Directory of Open Access Journals (Sweden)

    Seyed Abbas Taher

    2012-01-01

    Full Text Available Differential evolution (DE algorithm is used to determine optimal location of unified power quality conditioner (UPQC considering its size in the radial distribution systems. The problem is formulated to find the optimum location of UPQC based on an objective function (OF defined for improving of voltage and current profiles, reducing power loss and minimizing the investment costs considering the OF's weighting factors. Hence, a steady-state model of UPQC is derived to set in forward/backward sweep load flow. Studies are performed on two IEEE 33-bus and 69-bus standard distribution networks. Accuracy was evaluated by reapplying the procedures using both genetic (GA and immune algorithms (IA. Comparative results indicate that DE is capable of offering a nearer global optimal in minimizing the OF and reaching all the desired conditions than GA and IA.

  1. Quasilinear Evolution of Multiple Non-thermal Ion Distributions in ICRF Heating

    International Nuclear Information System (INIS)

    The AORSA global-wave solver is combined with the CQL3D bounce-averaged Fokker-Planck code to simulate the quasilinear evolution of non-thermal distributions in ion cyclotron resonance heating of tokamak plasmas. A novel re-formulation of the quasilinear operator enables calculation of the velocity space diffusion coefficients directly from the global wave fields. To obtain self-consistency between the wave fields and particle distribution function, AORSA and CQL3D have been iteratively coupled using Python. The combined self-consistent model is applied to minority ion heating in the Alcator C-Mod tokamak. Results show the formation of a 70 keV ion tail near the minority ion cyclotron resonance layer in approximate agreement with measurements from charge exchange neutral particle analyzers.

  2. Quasilinear evolution of non-thermal distributions in ion cyclotron resonance heating of tokamak plasmas

    International Nuclear Information System (INIS)

    The AORSA global-wave solver is combined with the CQL3D bounce-averaged Fokker-Planck code to simulate the quasilinear evolution of non-thermal distributions in ion cyclotron resonance heating of tokamak plasmas. A novel re-formulation of the quasilinear operator enables calculation of the velocity space diffusion coefficients directly from the global wave fields. To obtain self-consistency between the wave fields and particle distribution function, AORSA and CQL3D have been iteratively coupled using Python. The combined selfconsistent model is applied to minority ion heating in the Alcator C-Mod tokamak. Results show the formation of a 70 keV ion tail near the minority ion cyclotron resonance layer in approximate agreement with measurements from charge exchange neutral particle analyzers

  3. QCD evolution of (un)polarized gluon TMDPDFs and the Higgs $q_T$-distribution

    CERN Document Server

    Echevarria, Miguel G; Mulders, Piet J; Pisano, Cristian

    2015-01-01

    We provide the proper definition of all the leading-twist (un)polarized gluon transverse momentum dependent parton distribution functions (TMDPDFs), by considering the Higgs boson transverse momentum distribution in hadron-hadron collisions and deriving the factorization theorem in terms of them. We show that the evolution of all the (un)polarized gluon TMDPDFs is driven by a universal evolution kernel, which can be resummed up to next-to-next-to-leading-logarithmic accuracy. Considering the proper definition of gluon TMDPDFs, we perform an explicit next-to-leading-order calculation of the unpolarized ($f_1^g$), linearly polarized ($h_1^{\\perp g}$) and helicity ($g_{1L}^g$) gluon TMDPDFs, and show that, as expected, they are free from rapidity divergences. As a byproduct, we obtain the Wilson coefficients of the refactorization of these TMDPDFs at large transverse momentum. In particular, the coefficient of $g_{1L}^g$, which has never been calculated before, constitutes a new and necessary ingredient for a re...

  4. Knowledge Evolution in Distributed Geoscience Datasets and the Role of Semantic Technologies

    Science.gov (United States)

    Ma, X.

    2014-12-01

    Knowledge evolves in geoscience, and the evolution is reflected in datasets. In a context with distributed data sources, the evolution of knowledge may cause considerable challenges to data management and re-use. For example, a short news published in 2009 (Mascarelli, 2009) revealed the geoscience community's concern that the International Commission on Stratigraphy's change to the definition of Quaternary may bring heavy reworking of geologic maps. Now we are in the era of the World Wide Web, and geoscience knowledge is increasingly modeled and encoded in the form of ontologies and vocabularies by using semantic technologies. Accordingly, knowledge evolution leads to a consequence called ontology dynamics. Flouris et al. (2008) summarized 10 topics of general ontology changes/dynamics such as: ontology mapping, morphism, evolution, debugging and versioning, etc. Ontology dynamics makes impacts at several stages of a data life cycle and causes challenges, such as: the request for reworking of the extant data in a data center, semantic mismatch among data sources, differentiated understanding of a same piece of dataset between data providers and data users, as well as error propagation in cross-discipline data discovery and re-use (Ma et al., 2014). This presentation will analyze the best practices in the geoscience community so far and summarize a few recommendations to reduce the negative impacts of ontology dynamics in a data life cycle, including: communities of practice and collaboration on ontology and vocabulary building, link data records to standardized terms, and methods for (semi-)automatic reworking of datasets using semantic technologies. References: Flouris, G., Manakanatas, D., Kondylakis, H., Plexousakis, D., Antoniou, G., 2008. Ontology change: classification and survey. The Knowledge Engineering Review 23 (2), 117-152. Ma, X., Fox, P., Rozell, E., West, P., Zednik, S., 2014. Ontology dynamics in a data life cycle: Challenges and recommendations

  5. Evolution of fractal agglomeration behaviour of Ca/Sr doped nano-crystalline lanthanum chromites under sintering: a small angle neutron scattering investigation

    International Nuclear Information System (INIS)

    Full text: In present study, sintering behaviour of calcium doped lanthanum chromite (La0.7Ca0.3CrO3) (LCC) and strontium doped chromite (La0.8Sr0.2CrO3) (LSC) powders which is used as interconnect material for SOFC application, synthesized through a gel combustion route, have been studied. Fractal morphology in LCC and LSC powder aggregate has been investigated using small angle neutron scattering (SANS) technique for different sintering temperatures. A comparison of the evolution of mesoscopic structure has also been elucidated for the two materials at different sintering temperatures. X-ray diffraction experiments show the isostructural crystalline structure for both powders. Neutron scattering data reveal a fractal type correlation of building blocks in the as-formed powders. An increase in fractal dimension and a reduction in upper cutoff were found as sintering progresses indicating a compaction of agglomerates with increasing sintering temperature. At about 1200 deg C sintering temperature, the fractal characteristics morphology disappears almost completely. This is due to relatively faster diffusion mechanism at higher sintering temperatures and also because of better sinterability of the nano-particles compared to their bulk counterpart. Possibility of transient liquid phase sintering and phase transition assisted sintering process at higher sintering temperature may also be a possibility. Comparison of SANS profiles for LCC and LSC powders indicate that agglomerates in initial virgin powder of LSC are relatively more loose and larger in nature as compared to that of LCC. This reveals that the sintering efficiency of virgin powder of LCC is relatively easy than that of LSC in spite of their isothermal crystalline phase

  6. Evolution process of regular structure in isothermal crystallization phenomena of crystalline polymers viewed from synchrotron small- and wide-angle x-ray scatterings and vibrational spectroscopy

    International Nuclear Information System (INIS)

    The evolution processes of regular structure in isothermal crystallization phenomena of crystalline polymers have been investigated from the viewpoints of molecular level, crystal lattice, and higher-order structure on the basis of time-dependent infrared spectral data and synchrotron small- (SAXS) and wide-angle X-ray scattering (WAXD) data. The polymers treated here were isotactic polypropylene (iPP), nylon 10/10 and polyoxymethylene (POM). In the case of iPP, the formation and growing processes of regular helical segments in the molten state are described by utilizing the concept of critical sequential length for infrared bands. Combination of these spectroscopic data with the SAXS and WAXD data clarifies the formation process of domains consisting of regular helical segments, the increment of correlation of neighboring domains, and the development of stacked lamellar structure, during which the remarkable growth of crystal lattices consisting of regular helices occurs in parallel. In the case of nylon 10/10, weak hydrogen bonds are formed between amide groups even in the molten state. Once the isothermal crystallization starts to occur, these more-or-less correlated domains built up by the hydrogen bonds are formed followed by the formation of crystal lattices consisting of relatively regular methylene segments. Such growth is quite different from the case of iPP crystallization. The study of POM is based on the observation of infrared bands intrinsic to the folded chain crystals (FCC) and extended chain crystals (ECC). From the time-resolved measurements of these infrared bands as well as the SAXS and WAXD in the isothermal crystallization process of POM, we clarified that the lamellar structure of FCC morphology is formed at first. Then some new lamellae are formed in between these original lamellae, resulting in the formation of ECC parts in which the regular helices pass through the several neighboring lamellae as taut tie chains. (author)

  7. Vertical and wide-angle seismic exploration of crustal structure, and the active evolution of the North Aegean Trough between the Sea of Marmara and Gulf of Corinth

    Science.gov (United States)

    Sachpazi, M.; Vigner, A.; Laigle, M.; Hirn, A.; Roussos, N.

    2003-04-01

    and reflectors interpreted as the top and the base of the lower crust. Based on the consistency of seismic evidence over the different profiles, though this is faint on each taken by itself, clear basement-involving faults that appear tosole into an upper crustal reflective domain which is interpreted as a shallow dipping detachment. These profiles reveal also uppercrustal structures consistent with the evolution in time and space of such a detachment. The latter has low angle dip grossly northeastward, from very shallow under the base of sediments in the SW corner of the NAT (N of Sporadhes Islands) to the 10 km depth where the active normal fault on the northern slope has been imaged. It is imaged in a joint consideration of the pres-stack depth migrated line and of the stack with multiple-suppression. Beneath, the top of the lower crust and the Moho are imaged in places. In-line and broadside wide-angle recordings by stations along the Magnesian peninsula and Evvia detect an abnormaly shallow position and facies of the lower crust under the southwestern edge of the NAT. Its extent is limited by the southern and western edges of the NAT and it can be viewed as marking the location of largest finite thinning of the upper crust. Striction and transport along the detachment are suggested to occur by the drag of the SW transported southern limb to the North Anatolian fault at the North Sporadhes escarpment.

  8. Scoliosis angle

    International Nuclear Information System (INIS)

    The most commonly used methods of assessing the scoliotic deviation measure angles that are not clearly defined in relation to the anatomy of the patient. In order to give an anatomic basis for such measurements it is proposed to define the scoliotic deviation as the deviation the vertebral column makes with the sagittal plane. Both the Cobb and the Ferguson angles may be based on this definition. The present methods of measurement are then attempts to measure these angles. If the plane of these angles is parallel to the film, the measurement will be correct. Errors in the measurements may be incurred by the projection. A hypothetical projection, called a 'rectified orthogonal projection', is presented, which correctly represents all scoliotic angles in accordance with these principles. It can be constructed in practice with the aid of a computer and by performing measurements on two projections of the vertebral column; a scoliotic curve can be represented independent of the kyphosis and lordosis. (Auth.)

  9. Anisotropic pitch angle distribution of ~100 keV microburst electrons in the loss cone: measurements from STSAT-1

    Directory of Open Access Journals (Sweden)

    J. J. Lee

    2012-11-01

    Full Text Available Electron microburst energy spectra in the range of 170 keV to 360 keV have been measured using two solid-state detectors onboard the low-altitude (680 km, polar-orbiting Korean STSAT-1 (Science and Technology SATellite-1. Applying a unique capability of the spacecraft attitude control system, microburst energy spectra have been accurately resolved into two components: perpendicular to and parallel to the geomagnetic field direction. The former measures trapped electrons and the latter those electrons with pitch angles in the loss cone and precipitating into atmosphere. It is found that the perpendicular component energy spectra are harder than the parallel component and the loss cone is not completely filled by the electrons in the energy range of 170 keV to 360 keV. These results have been modeled assuming a wave-particle cyclotron resonance mechanism, where higher energy electrons travelling within a magnetic flux tube interact with whistler mode waves at higher latitudes (lower altitudes. Our results suggest that because higher energy (relativistic microbursts do not fill the loss cone completely, only a small portion of electrons is able to reach low altitude (~100 km atmosphere. Thus assuming that low energy microbursts and relativistic microbursts are created by cyclotron resonance with chorus elements (but at different locations, the low energy portion of the microburst spectrum will dominate at low altitudes. This explains why relativistic microbursts have not been observed by balloon experiments, which typically float at altitudes of ~30 km and measure only X-ray flux produced by collisions between neutral atmospheric particles and precipitating electrons.

  10. Evolution of the ATLAS distributed computing system during the LHC long shutdown

    International Nuclear Information System (INIS)

    The ATLAS Distributed Computing project (ADC) was established in 2007 to develop and operate a framework, following the ATLAS computing model, to enable data storage, processing and bookkeeping on top of the Worldwide LHC Computing Grid (WLCG) distributed infrastructure. ADC development has always been driven by operations and this contributed to its success. The system has fulfilled the demanding requirements of ATLAS, daily consolidating worldwide up to 1 PB of data and running more than 1.5 million payloads distributed globally, supporting almost one thousand concurrent distributed analysis users. Comprehensive automation and monitoring minimized the operational manpower required. The flexibility of the system to adjust to operational needs has been important to the success of the ATLAS physics program. The LHC shutdown in 2013-2015 affords an opportunity to improve the system in light of operational experience and scale it to cope with the demanding requirements of 2015 and beyond, most notably a much higher trigger rate and event pileup. We will describe the evolution of the ADC software foreseen during this period. This includes consolidating the existing Production and Distributed Analysis framework (PanDA) and ATLAS Grid Information System (AGIS), together with the development and commissioning of next generation systems for distributed data management (DDM/Rucio) and production (Prodsys-2). We will explain how new technologies such as Cloud Computing and NoSQL databases, which ATLAS investigated as R and D projects in past years, will be integrated in production. Finally, we will describe more fundamental developments such as breaking job-to-data locality by exploiting storage federations and caches, and event level (rather than file or dataset level) workload engines.

  11. Evolution of the ATLAS distributed computing system during the LHC long shutdown

    Science.gov (United States)

    Campana, S.; Atlas Collaboration

    2014-06-01

    The ATLAS Distributed Computing project (ADC) was established in 2007 to develop and operate a framework, following the ATLAS computing model, to enable data storage, processing and bookkeeping on top of the Worldwide LHC Computing Grid (WLCG) distributed infrastructure. ADC development has always been driven by operations and this contributed to its success. The system has fulfilled the demanding requirements of ATLAS, daily consolidating worldwide up to 1 PB of data and running more than 1.5 million payloads distributed globally, supporting almost one thousand concurrent distributed analysis users. Comprehensive automation and monitoring minimized the operational manpower required. The flexibility of the system to adjust to operational needs has been important to the success of the ATLAS physics program. The LHC shutdown in 2013-2015 affords an opportunity to improve the system in light of operational experience and scale it to cope with the demanding requirements of 2015 and beyond, most notably a much higher trigger rate and event pileup. We will describe the evolution of the ADC software foreseen during this period. This includes consolidating the existing Production and Distributed Analysis framework (PanDA) and ATLAS Grid Information System (AGIS), together with the development and commissioning of next generation systems for distributed data management (DDM/Rucio) and production (Prodsys-2). We will explain how new technologies such as Cloud Computing and NoSQL databases, which ATLAS investigated as R&D projects in past years, will be integrated in production. Finally, we will describe more fundamental developments such as breaking job-to-data locality by exploiting storage federations and caches, and event level (rather than file or dataset level) workload engines.

  12. Evolution of earthquake rupture potential along active faults, inferred from seismicity rates and size distributions

    Science.gov (United States)

    Tormann, Thessa; Wiemer, Stefan; Enescu, Bogdan; Woessner, Jochen

    2016-04-01

    One of the major unresolved questions in seismology is the evolution in time and space of the earthquake rupture potential and thus time-dependent hazard along active faults. What happens after a major event: is the potential for further large events reduced as predicted from elastic rebound, or increased as proposed by current-state short-term clustering models? How does the rupture potential distribute in space, i.e. does it reveal imprints of stress transfer? Based on the rich earthquake record from the Pacific Plate along the Japanese coastline we investigate what information on spatial distributions and temporal changes of a normalized rupture potential (NRP) for different magnitudes can be derived from time-varying, local statistical characteristics of well and frequently observed small-to-moderate seismicity. Seismicity records show strong spatio-temporal variability in both activity rates and size distribution. We analyze 18 years of seismicity, including the massive 2011 M9 Tohoku earthquake and its aftermath. We show that the size distribution of earthquakes has significantly changed before (increased fraction of larger magnitudes) and after that mainshock (increased fraction of smaller magnitudes), strongest in areas of highest coseismic slip. Remarkably, a rapid recovery of this effect is observed within only few years. We combine this significant temporal variability in earthquake size distributions with local activity rates and infer the evolution of NRP distributions. We study complex spatial patterns and how they evolve, and more detailed temporal characteristics in a simplified spatial selection, i.e. inside and outside the high slip zone of the M9 earthquake. We resolve an immediate and strong NRP increase for large events prior to the Tohoku event in the subsequent high slip patch and a very rapid decrease inside this high-stress-release area, coupled with a lasting increase of NRP in the immediate surroundings. Even in the center of the Tohoku

  13. QCD evolution of (un)polarized gluon TMDPDFs and the Higgs q T -distribution

    Science.gov (United States)

    Echevarria, Miguel G.; Kasemets, Tomas; Mulders, Piet J.; Pisano, Cristian

    2015-07-01

    We provide the proper definition of all the leading-twist (un)polarized gluon transverse momentum dependent parton distribution functions (TMDPDFs), by considering the Higgs boson transverse momentum distribution in hadron-hadron collisions and deriving the factorization theorem in terms of them. We show that the evolution of all the (un)polarized gluon TMDPDFs is driven by a universal evolution kernel, which can be resummed up to next-to-next-to-leading-logarithmic accuracy. Considering the proper definition of gluon TMDPDFs, we perform an explicit next-to-leading-order calculation of the unpolarized ( f {1/ g }), linearly polarized ( h {1/⊥ g }) and helicity ( g {1/L g }) gluon TMDPDFs, and show that, as expected, they are free from rapidity divergences. As a byproduct, we obtain the Wilson coefficients of the refactorization of these TMDPDFs at large transverse momentum. In particular, the coefficient of g {1/L g }, which has never been calculated before, constitutes a new and necessary ingredient for a reliable phenomenological extraction of this quantity, for instance at RHIC or the future AFTER@LHC or Electron-Ion Collider. The coefficients of f {1/ g } and h {1/⊥ g } have never been calculated in the present formalism, although they could be obtained by carefully collecting and recasting previous results in the new TMD formalism. We apply these results to analyze the contribution of linearly polarized gluons at different scales, relevant, for instance, for the inclusive production of the Higgs boson and the C-even pseudoscalar bottomonium state η b . Applying our resummation scheme we finally provide predictions for the Higgs boson q T -distribution at the LHC.

  14. Vertical distribution, flight behaviour and evolution of wing morphology in Morpho butterflies.

    Science.gov (United States)

    Devries, P J; Penz, Carla M; Hill, Ryan I

    2010-09-01

    1. Flight is a key innovation in the evolution of insects that is crucial to their dispersal, migration, territoriality, courtship and predator avoidance. Male butterflies have characteristic territoriality and courtship flight behaviours, and females use a characteristic flight behaviour when searching for host plants. This implies that selection acts on wing morphology to maximize flight performance for conducting important behaviours among sexes. 2. Butterflies in the genus Morpho are obvious components of neotropical forests, and many observations indicate that they show two broad categories of flight behaviour and flight height. Although species can be categorized as using gliding or flapping flight, and flying at either canopy or understorey height, the association of flight behaviour and flight height with wing shape evolution has never been explored. 3. Two clades within Morpho differ in flight behaviour and height. Males and females of one clade inhabit the forest understorey and use flapping flight, whereas in the other clade, males use gliding flight at canopy level and females use flapping flight in both canopy and understorey. 4. We used independent contrasts to answer whether wing shape is associated with flight behaviour and height. Given a single switch to canopy habitation and gliding flight, we compared contrasts for the node at which the switch to canopy flight occurred with the distribution of values in the two focal clades. We found significant changes in wing shape at the transition to canopy flight only in males, and no change in size for either sex. A second node within the canopy clade suggests that other factors may also be involved in wing shape evolution. Our results reinforce the hypothesis that natural selection acts differently on male and female butterfly wing shape and indicate that the transition to canopy flight cannot explain all wing shape diversity in Morpho. 5. This study provides a starting point for characterizing evolution

  15. Modelling the evolution of 210Pb and 210Po size distributions in the atmosphere

    International Nuclear Information System (INIS)

    The study of radon (222Rn and 220Rn) decay products in the atmosphere is important for estimating air ionization, assessing the inhalation doses to humans and for understanding atmospheric transport processes. The decay products 218Po, 214Pb (T1/2 < 1 hour), 212Pb (T1/2 ∼ 10.6 hrs) are short lived and 210Po (T1/2 ∼ 13 days), 210Pb (T1/2 ∼ 22 years) are long lived. Within a short time after their formation, the decay product atom combine with air constituents to form molecular clusters which then get attached to existing aerosol particles. The activity size distributions of the short-lived components in the atmosphere show two major modes, namely fine and coarse modes. The long-lived components predominantly occur in the coarse mode. Several studies have been carried out on the decay product activity distributions to estimate their atmospheric residence times. An important aspect that has received little attention is the upward size evolution of the decay products due to the persistent coagulation of the coarse mode particles. The present study aims at the development of first principle model for progeny attachment dynamics to a coagulating aerosol, which will provide insight in understanding the evolution of activity size distribution. A theoretical model is formulated by considering the processes such a constant formation of background aerosols, attachment of progeny atoms to the aerosol, coagulation, physical decay, and deposition. A set of integro-differential equations for attached and unattached fractions are formulated and are solved by a comprehensive numerical approach. Comparative studies of the activity size distributions, the degree of mixing of radioactivity within particles are carried out for short-lived and long lived species. The results are in agreement with the observations which show that the mode of the activity size distribution strongly depends on the effective life time of the progeny species in the atmosphere. The size dependence of

  16. Evolution of the Distribution of Neutron Exposures in the Galaxy Disc: An Analytical Model

    Indian Academy of Sciences (India)

    Wenyuan Cui; Weijuan Zhang; Bo Zhang

    2007-03-01

    In this work, based on the analytical model with delayed production approximation developed by Pagel & Tautvaišienė (1995) for the Galaxy, the analytic solutions of the distribution of neutron exposures of the Galaxy (hereafter NEG) are obtained. The present results appear to reasonably reproduce the distribution of neutron exposures of the solar system (hereafter NES). The strong component and the main component of the NES are built up in different epochs. Firstly, the strong component is produced by the s-process nucleosynthesis in the metal-poor AGB stars, starting from [Fe/H] ≈ -1.16 to [Fe/H] ≈ -0.66, corresponding to the time interval 1.06 < < 2.6 Gyr. Secondly, the main component is produced by the s-process in the galactic disk AGB stars, starting from [Fe/H] ≈ -0.66 to [Fe/H] ≈ 0, corresponding to the time interval > 2.6 Gyr. The analytic solutions have the advantage of an understanding of the structure and the properties of the NEG. The NEG is believed to be an effective tool to study the s-process element abundance distributions in the Galaxy at different epochs and the galactic chemical evolution of the neutron-capture elements.

  17. Collisionless Evolution of Isotropic Alpha-Particle Distribution in a Tokamak

    International Nuclear Information System (INIS)

    Full text: The density of the noninductive current generated due to collisionless motion of alpha-particles in the tokamak magnetic field is calculated. The analysis is based on fully three-dimensional calculations of charged particle trajectories without simplifying assumptions typical for drift and neoclassical approaches. The current is calculated over the entire cross section of the plasma column, including the magnetic axis. It is shown that the current density is not a function of a magnetic surface and is strongly polarized over the poloidal angle. The current density distribution in the tokamak poloidal cross section is obtained, and the current density as a function of the safety factor profile, the tokamak aspect ratio, and the ratio of the particle Larmor radius on the axis to the tokamak minor radius is determined. It is shown that, when the source of alpha-particles is spatially nonuniform, the current density in the center of the tokamak is nonzero due to asymmetry of the phase-space boundary between trapped and passing particles. The current density scaling in the tokamak center differs from the known approximations for the bootstrap current and is sensitive to the spatial distribution of alpha-particles. (author)

  18. The general behavior of $NLO$ unintegrated parton distributions based on the single-scale evolution and the angular ordering constraint

    CERN Document Server

    Hosseinkhani, H

    2010-01-01

    To overcome the complexity of generalized two hard scale ($k_t$,$\\mu$) evolution equation, well known as the $Ciafaloni$, $Catani$, $Fiorani$ and $Marchsini$ ($CCFM$) evolution equations, and calculate the unintegrated parton distribution functions ($UPDF$), $Kimber$, $Martin$ and $Ryskin$ ($KMR$) proposed a procedure based on ($i$) the inclusion of single-scale ($\\mu$) only at the last step of evolution and ($ii$) the angular ordering constraint ($AOC$) on the $DGLAP$ terms (the $DGLAP$ collinear approximation), to bring the second scale, $k_t$ into the $UPDF$ evolution equations. In this work we intend to use the $MSTW 2008$ (Martin et al) parton distribution functions (PDF) and try to calculate $UPDF$ for various values of $x$ (the longitudinal fraction of parton momentum), $\\mu$ (the probe scale) and $k_t$ (the parton transverse momentum) to see the general behavior of three dimensional $UPDF$ at the $NLO$ level up to the $LHC$ working energy scales ($\\mu^2)$. It is shown that there exits some pronounced ...

  19. Evolution equation for the higher-twist B-meson distribution amplitude

    Energy Technology Data Exchange (ETDEWEB)

    Braun, V.M.; Offen, N. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Manashov, A.N. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Sankt-Petersburg State Univ. (Russian Federation). Dept. of Theoretical Physics

    2015-07-15

    We find that the evolution equation for the three-particle quark-gluon B-meson light-cone distribution amplitude (DA) of subleading twist is completely integrable in the large N{sub c} limit and can be solved exactly. The lowest anomalous dimension is separated from the remaining, continuous, spectrum by a finite gap. The corresponding eigenfunction coincides with the contribution of quark-gluon states to the two-particle DA φ{sub -}(ω) so that the evolution equation for the latter is the same as for the leading-twist DA φ{sub +}(ω) up to a constant shift in the anomalous dimension. Thus, ''genuine'' three-particle states that belong to the continuous spectrum effectively decouple from φ{sub -}(ω) to the leading-order accuracy. In turn, the scale dependence of the full three-particle DA turns out to be nontrivial so that the contribution with the lowest anomalous dimension does not become leading at any scale. The results are illustrated on a simple model that can be used in studies of 1/m{sub b} corrections to heavy-meson decays in the framework of QCD factorization or light-cone sum rules.

  20. Optical and x-ray selected samples of quasars: evolution of the luminosity distributions

    International Nuclear Information System (INIS)

    Spectroscopic and X-ray observations were obtained of quasar candidates in the 1.72 deg2 region centered on 13/sup h/ 300 which were selected on the basis of ultraviolet excess. A complete sample totalling 35 quasars with B +10% of the observed X-ray background at 2 keV. The completion of identifications of quasar candidates with B 2. A parametric likelihood analysis of the joint redshift-luminosity distribution is developed and applied to the composite sample of 57 quasars with 17.0 L), is found to be described well by a steep power law, L-35, verified by non-parametric estimation. The PG quasar sample, consisting of 114 quasars with B 4deg2, is added to the data set and fitted with pure luminosity evolution (LE) models

  1. Evolution of the ATLAS PanDA Production and Distributed Analysis System

    International Nuclear Information System (INIS)

    The PanDA (Production and Distributed Analysis) system has been developed to meet ATLAS production and analysis requirements for a data-driven workload management system capable of operating at LHC data processing scale. PanDA has performed well with high reliability and robustness during the two years of LHC data-taking, while being actively evolved to meet the rapidly changing requirements for analysis use cases. We will present an overview of system evolution including automatic rebrokerage and reattempt for analysis jobs, adaptation for the CernVM File System, support for the multi-cloud model through which Tier-2 sites act as members of multiple clouds, pledged resource management and preferential brokerage, and monitoring improvements. We will also describe results from the analysis of two years of PanDA usage statistics, current issues, and plans for the future.

  2. Distribution and evolution of the serine/aspartate racemase family in invertebrates.

    Science.gov (United States)

    Uda, Kouji; Abe, Keita; Dehara, Yoko; Mizobata, Kiriko; Sogawa, Natsumi; Akagi, Yuki; Saigan, Mai; Radkov, Atanas D; Moe, Luke A

    2016-02-01

    Free D-amino acids have been found in various invertebrate phyla, while amino acid racemase genes have been identified in few species. The purpose of this study is to elucidate the distribution, function, and evolution of amino acid racemases in invertebrate animals. We searched the GenBank databases, and found 11 homologous serine racemase genes from eight species in eight different invertebrate phyla. The cloned genes were identified based on their maximum activity as Acropora millepora (Cnidaria) serine racemase (SerR) and aspartate racemase (AspR), Caenorhabditis elegans (Nematoda) SerR, Capitella teleta (Annelida) SerR, Crassostrea gigas (Mollusca) SerR and AspR, Dugesia japonica (Platyhelminthes) SerR, Milnesium tardigradum (Tardigrada) SerR, Penaeus monodon (Arthropoda) SerR and AspR and Strongylocentrotus purpuratus (Echinodermata) AspR. We found that Acropora, Aplysia, Capitella, Crassostrea and Penaeus had two amino acid racemase paralogous genes and these paralogous genes have evolved independently by gene duplication at their recent ancestral species. The transcriptome analyses using available SRA data and enzyme kinetic data suggested that these paralogous genes are expressed in different tissues and have different functions in vivo. Phylogenetic analyses clearly indicated that animal SerR and AspR are not separated by their particular racemase functions and form a serine/aspartate racemase family cluster. Our results revealed that SerR and AspR are more widely distributed among invertebrates than previously known. Moreover, we propose that the triple serine loop motif at amino acid positions 150-152 may be responsible for the large aspartate racemase activity and the AspR evolution from SerR. PMID:26352274

  3. Analyzing the Distribution and Chemical Evolution of Major Nitrogen Carriers within Protoplanetary Disks

    Science.gov (United States)

    Pegues, Jamila; Oberg, Karin

    2016-01-01

    Nitrogen is an important component in many of the world's known organic and inorganic compounds, and its presence is crucial for the existence and survival of life as we know it on Earth today. And yet, in comparison to the total amount of nitrogen available, nitrogen exists as a depleted resource throughout the Solar System, with Earth and unearthed meteorites featuring nitrogen levels depleted from 1 to 5 orders of magnitude relative to the Sun. Additionally, comets have been discovered that contain depleted levels of N2 in comparison to CO, despite the similar binding strengths of both N2 and CO to ices, with ices functioning as the main component in comets.Mechanisms that are likely to play a major part in the distribution of nitrogen throughout the Solar System, and other extra-solar systems, are condensation fronts, such as snowlines and snowsurfaces. Here, condensation fronts refer to the locations at which 50% of a given volatile is contained in gaseous form, while the other 50% is contained within grain form. During formation, astronomical bodies will accumulate different chemical compositions, depending upon where they form with respect to the locations of the condensation fronts within the system. In addition, a system's initial chemistry, as well as how that chemistry evolves, will ultimately alter how the volatiles in the system are distributed over time.Thus, the locations of these condensation fronts, coupled with a protoplanetary disk's initial chemistry and chemical evolution, are mechanisms that affect the eventual distribution and evolution of the disk's volatiles. In this project, we characterize and interpret these mechanisms within disk models. We vary the disk's time dependence and initial chemical conditions, and then analyze the effects of those variations upon the main carriers of nitrogen in both gaseous and grain form. From observed patterns and characteristics of these varied models, we evolve our understanding of curious nitrogen

  4. Angle-resolved intensity and energy distributions of positive and negative hydrogen ions released from tungsten surface by molecular hydrogen ion impact

    Science.gov (United States)

    Kato, S.; Tanaka, N.; Sasao, M.; Kisaki, M.; Tsumori, K.; Nishiura, M.; Matsumoto, Y.; Kenmotsu, T.; Wada, M.; Yamaoka, H.

    2015-08-01

    Hydrogen ion reflection properties have been investigated following the injection of H+, H2+ and H3+ ions onto a polycrystalline W surface. Angle- and energy-resolved intensity distributions of both scattered H+ and H- ions are measured by a magnetic momentum analyzer. We have detected atomic hydrogen ions reflected from the surface, while molecular hydrogen ions are unobserved within our detection limit. The reflected hydrogen ion energy is approximately less than one-third of the incident beam energy for H3+ ion injection and less than a half of that for H2+ ion injection. Other reflection properties are very similar to those of monoatomic H+ ion injection. Experimental results are compared to the classical trajectory simulations using the ACAT code based on the binary collision approximation.

  5. Angle-resolved intensity and energy distributions of positive and negative hydrogen ions released from tungsten surface by molecular hydrogen ion impact

    International Nuclear Information System (INIS)

    Hydrogen ion reflection properties have been investigated following the injection of H+, H2+ and H3+ ions onto a polycrystalline W surface. Angle- and energy-resolved intensity distributions of both scattered H+ and H− ions are measured by a magnetic momentum analyzer. We have detected atomic hydrogen ions reflected from the surface, while molecular hydrogen ions are unobserved within our detection limit. The reflected hydrogen ion energy is approximately less than one-third of the incident beam energy for H3+ ion injection and less than a half of that for H2+ ion injection. Other reflection properties are very similar to those of monoatomic H+ ion injection. Experimental results are compared to the classical trajectory simulations using the ACAT code based on the binary collision approximation

  6. Angle-resolved intensity and energy distributions of positive and negative hydrogen ions released from tungsten surface by molecular hydrogen ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S., E-mail: eun1302@mail4.doshsha.ac.jp [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Tanaka, N. [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Sasao, M. [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Kisaki, M.; Tsumori, K. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Nishiura, M. [University of Tokyo, Kashiwa, Chiba 277-8568 (Japan); Matsumoto, Y. [Tokushima Bunri University, Yamashiro, Tokushima 770-8514 (Japan); Kenmotsu, T.; Wada, M. [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Yamaoka, H. [RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan)

    2015-08-15

    Hydrogen ion reflection properties have been investigated following the injection of H{sup +}, H{sub 2}{sup +} and H{sub 3}{sup +} ions onto a polycrystalline W surface. Angle- and energy-resolved intensity distributions of both scattered H{sup +} and H{sup −} ions are measured by a magnetic momentum analyzer. We have detected atomic hydrogen ions reflected from the surface, while molecular hydrogen ions are unobserved within our detection limit. The reflected hydrogen ion energy is approximately less than one-third of the incident beam energy for H{sub 3}{sup +} ion injection and less than a half of that for H{sub 2}{sup +} ion injection. Other reflection properties are very similar to those of monoatomic H{sup +} ion injection. Experimental results are compared to the classical trajectory simulations using the ACAT code based on the binary collision approximation.

  7. Winding angle distribution for planar random walk, polymer ring entangled with an obstacle, and all that: Spitzer-Edwards-Prager-Frisch model revisited

    International Nuclear Information System (INIS)

    Using a general Green function formulation, we re-derive, both (i) Spitzer and his followers results for the winding angle distribution of the planar Brownian motion, and (ii) Edwards-Prager-Frisch results on the statistical mechanics of a ring polymer entangled with a straight bar. In the statistical mechanics part, we consider both cases of quenched and annealed topology. Among new results, we compute exactly the (expectation value of) the surface area of the locus of points such that each of them has linking number n with a given closed random walk trajectory (ring polymer). We also consider the generalizations of the problem for the finite diameter (disc-like) obstacle and winding within a cavity

  8. Distribution of the Reynolds stress tensor inside tip leakage vortex of a linear compressor cascade (I): effect of inlet flow angle

    International Nuclear Information System (INIS)

    A steady-state Reynolds averaged Navier-Stokes simulation was conducted to investigate the distribution of the Reynolds stress tensor inside tip leakage vortex of a linear compressor cascade. Two different inlet flow angles β=29.3 .deg. (design condition) and 36.5 .deg. (off-design condition) at a constant tip clearance size of 1% blade span were considered. Classical methods of solid mechanics, applied to view the Reynolds stress tensor in the principal direction system, clearly showed that the high anisotropic feature of turbulent flow field was dominant at the outer part of tip leakage vortex near the suction side of the blade and endwall flow separation region, whereas a nearly isotropic turbulence was found at the center of tip leakage vortex. There was no significant difference in the anisotropy of the Reynolds normal stresses inside tip leakage vortex between the design and off-design condition

  9. Avalanche dynamics in the Bak-Sneppen evolution model observed with a standard distribution width of fitness

    Science.gov (United States)

    Lee, Chaohong; Zhu, Xiwen; Gao, Kelin

    2003-01-01

    We introduce the standard distribution width of fitness to characterize the global and individual features of an ecosystem described by the Bak-Sneppen evolution model. Through tracking this quantity in evolution, a different hierarchy of avalanche dynamics, the w0 avalanche, is observed. The corresponding gap equation and the self-organized threshold wc are obtained. The critical exponents τ, γ and ρ, which describe the behaviour of the avalanche size distribution, the average avalanche size and the relaxation to attractor, respectively, are calculated by numerical simulation. The exact master equation and γ equation are derived, and the scaling relations are established among the critical exponents of this new avalanche.

  10. Nonadiabatic Hannay's Angle of Spin One Half in Grassmannian Version and Invariant Angle Coherent States

    OpenAIRE

    Cherbal, Omar; Maamache, Mustapha; Drir, Mahrez

    2003-01-01

    We propose to determinate the nonadiabatic Hannay’s angle of spin one half in a varying external magnetic field, by using an averaged version of the variational principal. We also show how the evolution and this nonadiabatic Hannay’s angle is associated with the evolution of Grassmannian invariant-angle coherent states.

  11. Codon information value and codon transition-probability distributions in short-term evolution

    Science.gov (United States)

    Jiménez-Montaño, M. A.; Coronel-Brizio, H. F.; Hernández-Montoya, A. R.; Ramos-Fernández, A.

    2016-07-01

    To understand the way the Genetic Code and the physical-chemical properties of coded amino acids affect accepted amino acid substitutions in short-term protein evolution, taking into account only overall amino acid conservation, we consider an underlying codon-level model. This model employs codon pair-substitution frequencies from an empirical matrix in the literature, modified for single-base mutations only. Ordering the degenerated codons according to their codon information value (Volkenstein, 1979), we found that three-fold and most of four-fold degenerated codons, which have low codon values, were best fitted to rank-frequency distributions with constant failure rate (exponentials). In contrast, almost all two-fold degenerated codons, which have high codon values, were best fitted to rank-frequency distributions with variable failure rate (inverse power-laws). Six-fold degenerated codons are considered to be doubly assigned. The exceptional behavior of some codons, including non-degenerate codons, is discussed.

  12. The Bluedisk Survey: molecular gas distribution and scaling relations in the context of galaxy evolution

    CERN Document Server

    Cormier, D; Wang, J; Pety, J; Usero, A; Roychowdhury, S; Carton, D; van der Hulst, J M; Jozsa, G I G; Garcia, M Gonzales; Saintonge, A

    2016-01-01

    One of the key goals of the Bluedisk survey is to characterize the impact of gas accretion in disc galaxies in the context of galaxy evolution. It contains 50 disc galaxies in the stellar mass range 10^10-10^11 Msun, of which half are bluer and more HI-rich galaxies than their HI-normal (control) counterparts. In this paper, we investigate how ongoing disc growth affects the molecular gas distribution and the star-formation efficiency in these galaxies. We present 12CO observations from the IRAM 30-m telescope in 26 galaxies of the Bluedisk survey. We compare the amount and spatial distribution of the molecular gas to key quantities such as atomic gas, stellar mass and surface density, star-formation rate and metallicity. We analyse the star-formation rate per unit gas (SFR/HI and SFR/H2) and relate all those parameters to general galaxy properties (HI-rich/control disc, morphology, etc.). We find that the HI-rich galaxies have similar H2 masses as the control galaxies. In their centres, HI-rich galaxies have...

  13. Extracting magnetic cluster size and its distributions in advanced perpendicular recording media with shrinking grain size using small angle x-ray scattering

    International Nuclear Information System (INIS)

    We analyze the magnetic cluster size (MCS) and magnetic cluster size distribution (MCSD) in a variety of perpendicular magnetic recording (PMR) media designs using resonant small angle x-ray scattering at the Co L3 absorption edge. The different PMR media flavors considered here vary in grain size between 7.5 and 9.5 nm as well as in lateral inter-granular exchange strength, which is controlled via the segregant amount. While for high inter-granular exchange, the MCS increases rapidly for grain sizes below 8.5 nm, we show that for increased amount of segregant with less exchange the MCS remains relatively small, even for grain sizes of 7.5 and 8 nm. However, the MCSD still increases sharply when shrinking grains from 8 to 7.5 nm. We show evidence that recording performance such as signal-to-noise-ratio on the spin stand correlates well with the product of magnetic cluster size and magnetic cluster size distribution

  14. Assessment of evaluated (n,d) energy-angle elastic scattering distributions using MCNP simulations of critical measurements and simplified calculation benchmarks

    International Nuclear Information System (INIS)

    Different evaluated (n,d) energy-angle elastic scattering distributions produce k-effective differences in MCNP5 simulations of critical experiments involving heavy water (D2O) of sufficient magnitude to suggest a need for new (n,d) scattering measurements and/or distributions derived from modern theoretical nuclear models, especially at neutron energies below a few MeV. The present work focuses on the small reactivity change of 2O coolant-void-reactivity calculation bias for simulations of two pairs of critical experiments performed in the ZED-2 reactor at the Chalk River Laboratories when different nuclear data libraries are used for deuterium. The deuterium data libraries tested include Endf/B-VII.0, Endf/B-VI.4, JENDL-3.3 and a new evaluation, labelled Bonn-B, which is based on recent theoretical nuclear-model calculations. Comparison calculations were also performed for a simplified, two-region, spherical model having an inner, 250-cm radius, homogeneous sphere of UO2, without and with deuterium, and an outer 20-cm-thick deuterium reflector. A notable observation from this work is the reduction of about 0.4 mk in the MCNP5 ZED-2 CVR calculation bias that is obtained when the O-in-UO2 thermal scattering data comes from Endf-B-VII.0. (author)

  15. Extracting magnetic cluster size and its distributions in advanced perpendicular recording media with shrinking grain size using small angle x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Virat; Ikeda, Yoshihiro; Takano, Ken; Terris, Bruce D.; Hellwig, Olav [San Jose Research Center, HGST a Western Digital company, 3403 Yerba Buena Rd., San Jose, California 95135 (United States); Wang, Tianhan [Department of Materials Science and Engineering, Stanford University, Stanford, California 94035 (United States); Stanford Institute for Materials and Energy Science (SIMES), SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Wu, Benny; Graves, Catherine [Stanford Institute for Materials and Energy Science (SIMES), SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94035 (United States); Dürr, Hermann A.; Scherz, Andreas; Stöhr, Jo [Stanford Institute for Materials and Energy Science (SIMES), SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

    2015-05-18

    We analyze the magnetic cluster size (MCS) and magnetic cluster size distribution (MCSD) in a variety of perpendicular magnetic recording (PMR) media designs using resonant small angle x-ray scattering at the Co L{sub 3} absorption edge. The different PMR media flavors considered here vary in grain size between 7.5 and 9.5 nm as well as in lateral inter-granular exchange strength, which is controlled via the segregant amount. While for high inter-granular exchange, the MCS increases rapidly for grain sizes below 8.5 nm, we show that for increased amount of segregant with less exchange the MCS remains relatively small, even for grain sizes of 7.5 and 8 nm. However, the MCSD still increases sharply when shrinking grains from 8 to 7.5 nm. We show evidence that recording performance such as signal-to-noise-ratio on the spin stand correlates well with the product of magnetic cluster size and magnetic cluster size distribution.

  16. Transverse momentum dependent parton distribution and fragmentation functions with QCD evolution

    Science.gov (United States)

    Aybat, S. Mert; Rogers, Ted C.

    2011-06-01

    We assess the current phenomenological status of transverse momentum dependent (TMD) parton distribution functions (PDFs) and fragmentation functions (FFs) and study the effect of consistently including perturbative QCD (pQCD) evolution. Our goal is to initiate the process of establishing reliable, QCD-evolved parametrizations for the TMD PDFs and TMD FFs that can be used both to test TMD factorization and to search for evidence of the breakdown of TMD factorization that is expected for certain processes. In this article, we focus on spin-independent processes because they provide the simplest illustration of the basic steps and can already be used in direct tests of TMD factorization. Our calculations are based on the Collins-Soper-Sterman (CSS) formalism, supplemented by recent theoretical developments which have clarified the precise definitions of the TMD PDFs and TMD FFs needed for a valid TMD-factorization theorem. Starting with these definitions, we numerically generate evolved TMD PDFs and TMD FFs using as input existing parametrizations for the collinear PDFs, collinear FFs, nonperturbative factors in the CSS factorization formalism, and recent fixed-scale fits. We confirm that evolution has important consequences, both qualitatively and quantitatively, and argue that it should be included in future phenomenological studies of TMD functions. Our analysis is also suggestive of extensions to processes that involve spin-dependent functions such as the Boer-Mulders, Sivers, or Collins functions, which we intend to pursue in future publications. At our website [http://projects.hepforge.org/tmd/], we have made available the tables and calculations needed to obtain the TMD parametrizations presented herein.

  17. Angle Resolved Photoemission Spectroscopy Studies of the Mott Insulator to Superconductor Evolution in Ca2-xNaxCuO2Cl2

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Kyle Michael

    2005-09-02

    It is widely believed that many of the exotic physical properties of the high-T{sub c} cuprate superconductors arise from the proximity of these materials to the strongly correlated, antiferromagnetic Mott insulating state. Therefore, one of the fundamental questions in the field of high-temperature superconductivity is to understand the insulator-to-superconductor transition and precisely how the electronic structure of Mott insulator evolves as the first holes are doped into the system. This dissertation presents high-resolution, doping dependent angle-resolved photoemission (ARPES) studies of the cuprate superconductor Ca{sub 2-x}Na{sub x}CuO{sub 2}Cl{sub 2}, spanning from the undoped parent Mott insulator to a high-temperature superconductor with a T{sub c} of 22 K. A phenomenological model is proposed to explain how the spectral lineshape, the quasiparticle band dispersion, and the chemical potential all progress with doping in a logical and self-consistent framework. This model is based on Franck-Condon broadening observed in polaronic systems where strong electron-boson interactions cause the quasiparticle residue, Z, to be vanishingly small. Comparisons of the low-lying states to different electronic states in the valence band strongly suggest that the coupling of the photohole to the lattice (i.e. lattice polaron formation) is the dominant broadening mechanism for the lower Hubbard band states. Combining this polaronic framework with high-resolution ARPES measurements finally provides a resolution to the long-standing controversy over the behavior of the chemical potential in the high-T{sub c} cuprates. This scenario arises from replacing the conventional Fermi liquid quasiparticle interpretation of the features in the Mott insulator by a Franck-Condon model, allowing the reassignment of the position of the quasiparticle pole. As a function of hole doping, the chemical potential shifts smoothly into the valence band while spectral weight is transferred

  18. Evolution of heavy quark distribution function in quark-gluon plasma: using the Iterative Laplace Transform Method

    CERN Document Server

    Pari, Sharareh Mehrabi; Shahri, Fatemeh Taghavi

    2015-01-01

    The "Iterative Laplace Transform Method" is used to solve the Fokker-Planck equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.

  19. A simple mathematical model of gradual Darwinian evolution: Emergence of a Gaussian trait distribution in adaptation along a fitness gradient

    OpenAIRE

    Biktashev, Vadim N.

    2011-01-01

    We consider a simple mathematical model of gradual Darwinian evolution in continuous time and continuous trait space, due to intraspecific competition for common resource in an asexually reproducing population in constant environment, while far from evolutionary stable equilibrium. The model admits exact analytical solution. In particular, Gaussian distribution of the trait emerges from generic initial conditions.

  20. Evolution of heavy quark distribution function on quark-gluon plasma: Using the Iterative Laplace Transform Method

    Directory of Open Access Journals (Sweden)

    Pari Sharareh Mehrabi

    2016-01-01

    Full Text Available The “Laplace Transform Method” is used to solve the Fokker-Plank equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.

  1. Influence of initial heterogeneities and recharge limitations on the evolution of aperture distributions in carbonate aquifers

    Directory of Open Access Journals (Sweden)

    B. Hubinger

    2011-12-01

    Full Text Available Karst aquifers evolve where the dissolution of soluble rocks causes the enlargement of discrete pathways along fractures or bedding planes, thus creating highly conductive solution conduits. To identify general interrelations between hydrogeological conditions and the properties of the evolving conduit systems the aperture-size frequency distributions resulting from generic models of conduit evolution are analysed. For this purpose, a process-based numerical model coupling flow and rock dissolution is employed. Initial protoconduits are represented by tubes with log-normally distributed aperture sizes with a mean μ0 = 0.5 mm for the logarithm of the diameters. Apertures are spatially uncorrelated and widen up to the metre range due to dissolution by chemically aggressive waters. Several examples of conduit development are examined focussing on influences of the initial heterogeneity and the available amount of recharge. If the available recharge is sufficiently high the evolving conduits compete for flow and those with large apertures and high hydraulic gradients attract more and more water. As a consequence, the positive feedback between increasing flow and dissolution causes the breakthrough of a conduit pathway connecting the recharge and discharge sides of the modelling domain. Under these competitive flow conditions dynamically stable bimodal aperture distributions are found to evolve, i.e. a certain percentage of tubes continues to be enlarged while the remaining tubes stay small-sized. The percentage of strongly widened tubes is found to be independent of the breakthrough time and decreases with increasing heterogeneity of the initial apertures and decreasing amount of available water. If the competition for flow is suppressed because the availability of water is strongly limited breakthrough of a conduit pathway is inhibited and the conduit pathways widen very slowly. The resulting aperture distributions are found to be

  2. The Evolution of the Baryon Distribution in the Universe from Cosmological Simulations

    CERN Document Server

    Durier, Fabrice

    2011-01-01

    The evolution of the baryon distribution in different phases, derived from cosmological simulations, are here reported. These computations indicate that presently most of baryons are in a warm-hot intergalactic (WHIM) medium (about 43%) while at z = 2.5 most of baryons constitute the diffuse medium (about 74%). Stars and the cold gas in galaxies represent only 14% of the baryons at z = 0. For z < 4 about a half of the metals are locked into stars while the fraction present in the WHIM and in the diffuse medium increases with a decreasing redshift. In the redshift range 0 < z < 2.5, the amount of metals in the WHIM increases from 4% to 22% while in the diffuse medium it increases from 0.6% to 4%. This enrichment process is due essentially to a turbulent diffusion mechanism associated to mass motions driven by supernova explosions. At z = 0, simulated blue (late type) galaxies show a correlation of the oxygen abundance present in the cold gas with the luminosity of the considered galaxy that agrees qui...

  3. Structure formation a spherical model for the evolution of the density distribution

    CERN Document Server

    Valageas, P

    1998-01-01

    Within the framework of hierarchical clustering we show that a simple Press-Schechter-like approximation, based on spherical dynamics, provides a good estimate of the evolution of the density field in the quasi-linear regime up to $\\Sigma \\sim 1$. Moreover, it allows one to recover the exact series of the cumulants of the probability distribution of the density contrast in the limit $\\Sigma \\to 0$ which sheds some light on the rigorous result and on ``filtering''. We also obtain similar results for the divergence of the velocity field. Next, we extend this prescription to the highly non-linear regime, using a stable-clustering approximation. Then we recover a specific scaling of the counts-in-cells which is indeed seen in numerical simulations, over a well-defined range. To this order we also introduce an explicit treatment of the behaviour of underdensities, which takes care of the normalization and is linked to the low-density bubbles and the walls one can see in numerical simulations. We compare this to a ...

  4. Evolution of a superbubble driven by sequential supernova explosions in a plane-stratified gas distribution

    International Nuclear Information System (INIS)

    The evolution of a superbubble driven by sequential explosions of supernovae in an OB association is studied. We especially focus on the effect of the plane-stratified gas distribution in the direction perpendicular to the galactic disk. It is shown that the superbubble asymmetrically expands with respect to the parallel and perpendicular directions to the disk. In the case that the density on the disk plane, n0, is ∼ 1 cm-3, it is found that the cooled shell surrounds the hot cavity like an egg shape. On the other hand, in a low-density disk with n0 ∼ 0.1 cm-3, a cooled wall is formed only on the disk plane side of the bubble and the hot gas flows up to the halo region. This corresponds to the HI worms pointed out by Heiles (1984; AAA 38.155.014). We can show that the hot gas which is pushed up maintains the galactic hot gaseous halo. (author)

  5. The Evolution of the EM Distribution in the Core of an Active Region

    CERN Document Server

    Del Zanna, Giulio; Mason, Helen; Subramanian, Srividya; O'Dwyer, Brendan

    2014-01-01

    We study the spatial distribution and evolution of the slope of the Emission Measure between 1 and 3~MK in the core active region NOAA~11193, first when it appeared near the central meridian and then again when it re-appeared after a solar rotation. We use observations recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) aboard Hinode, with a new radiometric calibration. We also use observations from the Atmospheric Imaging Assembly (AIA) aboard Solar Dynamics Observatory (SDO). We present the first spatially resolved maps of the EM slope in the 1--3~MK range within the core of the AR using several methods, both approximate and from the Differential Emission Measure (DEM). A significant variation of the slope is found at different spatial locations within the active region. We selected two regions that were not affected too much by any line-of-sight lower temperature emission. We found that the EM had a power law of the form EM~$\\propto T^{b}$, with b = 4.4$\\pm0.4$, and 4.6$\\pm0.4$, during the first...

  6. Genome-wide characterization of microsatellites in Triticeae species: abundance, distribution and evolution.

    Science.gov (United States)

    Deng, Pingchuan; Wang, Meng; Feng, Kewei; Cui, Licao; Tong, Wei; Song, Weining; Nie, Xiaojun

    2016-01-01

    Microsatellites are an important constituent of plant genome and distributed across entire genome. In this study, genome-wide analysis of microsatellites in 8 Triticeae species and 9 model plants revealed that microsatellite characteristics were similar among the Triticeae species. Furthermore, genome-wide microsatellite markers were designed in wheat and then used to analyze the evolutionary relationship of wheat and other Triticeae species. Results displayed that Aegilops tauschii was found to be the closest species to Triticum aestivum, followed by Triticum urartu, Triticum turgidum and Aegilops speltoides, while Triticum monococcum, Aegilops sharonensis and Hordeum vulgare showed a relatively lower PCR amplification effectivity. Additionally, a significantly higher PCR amplification effectivity was found in chromosomes at the same subgenome than its homoeologous when these markers were subjected to search against different chromosomes in wheat. After a rigorous screening process, a total of 20,666 markers showed high amplification and polymorphic potential in wheat and its relatives, which were integrated with the public available wheat markers and then anchored to the genome of wheat (CS). This study not only provided the useful resource for SSR markers development in Triticeae species, but also shed light on the evolution of polyploid wheat from the perspective of microsatellites. PMID:27561724

  7. A combined NLP-differential evolution algorithm approach for the optimization of looped water distribution systems

    Science.gov (United States)

    Zheng, Feifei; Simpson, Angus R.; Zecchin, Aaron C.

    2011-08-01

    This paper proposes a novel optimization approach for the least cost design of looped water distribution systems (WDSs). Three distinct steps are involved in the proposed optimization approach. In the first step, the shortest-distance tree within the looped network is identified using the Dijkstra graph theory algorithm, for which an extension is proposed to find the shortest-distance tree for multisource WDSs. In the second step, a nonlinear programming (NLP) solver is employed to optimize the pipe diameters for the shortest-distance tree (chords of the shortest-distance tree are allocated the minimum allowable pipe sizes). Finally, in the third step, the original looped water network is optimized using a differential evolution (DE) algorithm seeded with diameters in the proximity of the continuous pipe sizes obtained in step two. As such, the proposed optimization approach combines the traditional deterministic optimization technique of NLP with the emerging evolutionary algorithm DE via the proposed network decomposition. The proposed methodology has been tested on four looped WDSs with the number of decision variables ranging from 21 to 454. Results obtained show the proposed approach is able to find optimal solutions with significantly less computational effort than other optimization techniques.

  8. Revisiting the theory of the evolution of pick-up ion distributions: magnetic or adiabatic cooling?

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2008-01-01

    Full Text Available We study the phasespace behaviour of heliospheric pick-up ions after the time of their injection as newly created ions into the solar wind bulk flow from either charge exchange or photoionization of interplanetary neutral atoms. As interaction with the ambient MHD wave fields we allow for rapid pitch angle diffusion, but for the beginning of this paper we shall neglect the effect of quasilinear or nonlinear energy diffusion (Fermi-2 acceleration induced by counterflowing ambient waves. In the up-to-now literature connected with the convection of pick-up ions by the solar wind only adiabatic cooling of these ions is considered which in the solar wind frame takes care of filling the gap between the injection energy and energies of the thermal bulk of solar wind ions. Here we reinvestigate the basics of the theory behind this assumption of adiabatic pick-up ion reactions and correlated predictions derived from it. We then compare it with the new assumption of a pure magnetic cooling of pick-up ions simply resulting from their being convected in an interplanetary magnetic field which decreases in magnitude with increase of solar distance. We compare the results for pick-up ion distribution functions derived along both ways and can point out essential differences of observational and diagnostic relevance. Furthermore we then include stochastic acceleration processes by wave-particle interactions. As we can show, magnetic cooling in conjunction with diffusive acceleration by wave-particle interaction allows for an unbroken power law with the unique power index γ=−5 beginning from lowest velocities up to highest energy particles of about 100 KeV which just marginally can be in resonance with magnetoacoustic turbulences. Consequences for the resulting pick-up ion pressures are also analysed.

  9. Accurate Size and Size-Distribution Determination of Polystyrene Latex Nanoparticles in Aqueous Medium Using Dynamic Light Scattering and Asymmetrical Flow Field Flow Fractionation with Multi-Angle Light Scattering

    Directory of Open Access Journals (Sweden)

    Shinichi Kinugasa

    2012-01-01

    Full Text Available Accurate determination of the intensity-average diameter of polystyrene latex (PS-latex by dynamic light scattering (DLS was carried out through extrapolation of both the concentration of PS-latex and the observed scattering angle. Intensity-average diameter and size distribution were reliably determined by asymmetric flow field flow fractionation (AFFFF using multi-angle light scattering (MALS with consideration of band broadening in AFFFF separation. The intensity-average diameter determined by DLS and AFFFF-MALS agreed well within the estimated uncertainties, although the size distribution of PS-latex determined by DLS was less reliable in comparison with that determined by AFFFF-MALS.

  10. Distribution of functional groups in periodic mesoporous organosilica materials studied by small-angle neutron scattering with in situ adsorption of nitrogen

    Directory of Open Access Journals (Sweden)

    Monir Sharifi

    2012-05-01

    Full Text Available Periodic mesoporous materials of the type (R′O3Si-R-Si(OR′3 with benzene as an organic bridge and a crystal-like periodicity within the pore walls were functionalized with SO3H or SO3− groups and investigated by small-angle neutron scattering (SANS with in situ nitrogen adsorption at 77 K. If N2 is adsorbed in the pores the SANS measurements show a complete matching of all of the diffraction signals that are caused by the long-range ordering of the mesopores in the benzene-PMO, due to the fact that the benzene-PMO walls possess a neutron scattering length density (SLD similar to that of nitrogen in the condensed state. However, signals at higher q-values (>1 1/Å are not affected with respect to their SANS intensity, even after complete pore filling, confirming the assumption of a crystal-like periodicity within the PMO material walls due to π–π interactions between the organic bridges. The SLD of pristine benzene-PMO was altered by functionalizing the surface with different amounts of SO3H-groups, using the grafting method. For a low degree of functionalization (0.81 mmol SO3H·g−1 and/or an inhomogeneous distribution of the SO3H-groups, the SLD changes only negligibly, and thus, complete contrast matching is still found. However, for higher amounts of SO3H-groups (1.65 mmol SO3H·g−1 being present in the mesopores, complete matching of the neutron diffraction signals is no longer observed proving that homogeneously distributed SO3H-groups on the inner pore walls of the benzene-PMO alter the SLD in a way that it no longer fits to the SLD of the condensed N2.

  11. Three-dimensional shapes and distribution of FePd nanoparticles observed by electron tomography using high-angle annular dark-field scanning transmission electron microscopy

    Science.gov (United States)

    Sato, Kazuhisa; Aoyagi, Kenta; Konno, Toyohiko J.

    2010-01-01

    We have studied three-dimensional shapes and distribution of FePd nanoparticles, prepared by electron beam deposition and postdeposition annealing, by means of single-axis tilt tomography using atomic number contrasts obtained by high-angle annular dark-field scanning transmission electron microscopy. Particle size, shape, and locations were reconstructed by weighted backprojection (WBP), as well as by simultaneous iterative reconstruction technique (SIRT). We have also estimated the particle size by simple extrapolation of tilt-series original data sets, which proved to be quite powerful. The results of the two algorithms for reconstruction have been compared quantitatively with those obtained by the extrapolation method and those independently reported by electron holography. It was found that the reconstructed intensity map by WBP contains a small amount of dotlike artifacts, which do not exist in the results by SIRT, and that the particle surface obtained by WBP is rougher than that by SIRT. We demonstrate, on the other hand, that WBP yields a better estimation of the particle size in the z direction than SIRT does, most likely due to the presence of a "missing wedge" in the original data set.

  12. The Distribution of Antarctic Subglacial Lake Environments With Implications for Their Origin and Evolution

    Science.gov (United States)

    Blankenship, D. D.; Young, D. A.; Carter, S. P.

    2006-12-01

    evolving ice sheet control the location of subglacial lakes or does the fixed lithospheric character necessary for lake formation constrain the evolution of ice sheet catchments? To begin to answer these questions, we assess the distributions of classes of lakes defined by their reflection character. These classes include bright specular ("definite") lakes, dim specular lakes and bright non-specular ("fuzzy") lakes. Interestingly, it is the fuzzy lakes that do not strongly correlate with ice divides. We show specific examples of off-divide lake system hydrology from the Byrd Glacier catchment in East Antarctica and Kamb Ice Stream in West Antarctica.

  13. Search for the algorithm of genes distribution during the process of microbial evolution

    Science.gov (United States)

    Pikuta, Elena V.

    2015-09-01

    Previous two and three dimensional graph analysis of eco-physiological data of Archaea demonstrated specific geometry for distribution of major Prokaryotic groups in a hyperboloid function. The function of a two-sheet hyperboloid covered all known biological groups, and therefore, could be applied for the entire evolution of life on Earth. The vector of evolution was indicated from the point of hyper temperature, extreme acidity and low salinity to the point of low temperature and increased alkalinity and salinity. According to this vector, the following groups were chosen for the gene screening analysis. In the vector "High-Temperature → Low-Temperature" within extreme acidic pH (0-3), it is: 1) the hyperthermophilic Crenarchaeota - order Sulfolobales, 2) moderately thermophilic Euryarchaeota - Class Thermoplasmata, and 3) mesophilic acidophiles- genus Thiobacillus and others. In the vector "Low pH → High pH" the following groups were selected in three temperature ranges: a) Hyperthermophilic Archaea and Eubacteria, b) moderately thermophilic - representatives of the genera Anaerobacter and Anoxybacillus, and c) mesophilic haloalkaliphiles (Eubacteria and Archaea). The genes associated with acidophily (H+ pump), chemolitho-autotrophy (proteins of biochemichal cycles), polymerases, and histones were proposed for the first vector, and for the second vector the genes associated with halo-alkaliphily (Na+ pumps), enzymes of organotrophic metabolisms (sugar- and proteolytics), and others were indicated for the screening. Here, an introduction to the phylogenetic constant (ρη) is presented and discussed. This universal characteristic is calculated for two principally different life forms -Prokaryotes and Eukaryotes; Existence of the second type of living forms is impossible without the first one. The number of chromosomes in Prokaryotic organisms is limited to one (with very rare exceptions, to two), while in Eukaryotic organisms this number is larger. Currently

  14. On the spatial distribution and evolution of ultrafine aerosols in urban air

    Science.gov (United States)

    Dall'Osto, M.; Querol, X.; Alastuey, A.; O'Dowd, C.; Harrison, R. M.; Wenger, J.; Gómez-Moreno, F. J.

    2012-07-01

    Sources and evolution of ultrafine particles (5nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under clean atmospheric conditions (low condensation sinks, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. This is also evident in the urban background annual mean diurnal trend of N/BC, showing a midday peak in all seasons. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5nm) allow us to identify two types of nucleation and growth events: a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding background area; and an urban type which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the best compromise between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre is a source of both non-volatile traffic primary (29-39%) and secondary freshly nucleated particles (up to 61-71%) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

  15. Evolution of uranium distribution and speciation in mill tailings, COMINAK Mine, Niger.

    Science.gov (United States)

    Déjeant, Adrien; Galoisy, Laurence; Roy, Régis; Calas, Georges; Boekhout, Flora; Phrommavanh, Vannapha; Descostes, Michael

    2016-03-01

    This study investigated the evolution of uranium distribution and speciation in mill tailings from the COMINAK mine (Niger), in production since 1978. A multi-scale approach was used, which combined high resolution remote sensing imagery, ICP-MS bulk rock analyses, powder X-ray diffraction, Scanning Electron Microscopy, Focused Ion Beam--Transmission Electron Microscopy and X-ray Absorption Near Edge Spectroscopy. Mineralogical analyses showed that some ore minerals, including residual uraninite and coffinite, undergo alteration and dissolution during tailings storage. The migration of uranium and other contaminants depends on (i) the chemical stability of secondary phases and sorbed species (dissolution and desorption processes), and (ii) the mechanical transport of fine particles bearing these elements. Uranium is stabilized after formation of secondary uranyl sulfates and phosphates, and adsorbed complexes on mineral surfaces (e.g. clay minerals). In particular, the stock of insoluble uranyl phosphates increases with time, thus contributing to the long-term stabilization of uranium. At the surface, a sulfate-cemented duricrust is formed after evaporation of pore water. This duricrust limits water infiltration and dust aerial dispersion, though it is enriched in uranium and many other elements, because of pore water rising from underlying levels by capillary action. Satellite images provided a detailed description of the tailings pile over time and allow monitoring of the chronology of successive tailings deposits. Satellite images suggest that uranium anomalies that occur at deep levels in the pile are most likely former surface duricrusts that have been buried under more recent tailings. PMID:26747998

  16. Multimodal particle size distribution or fractal surface of acrylic acid copolymer nanoparticles: A small-angle X-ray scattering study using direct Fourier and indirect maximum entropy methods

    OpenAIRE

    Mueller, J.J.; Hansen, S; Lukowski, G.; Gast, K.

    1995-01-01

    Acrylic acid copolymers are potential carriers for drug delivery. The surface, surface rugosity and the absolute dimension of the particles are parameters that determine the binding of drugs or detergents, diffusion phenomena at the surface and the distribution of the carrier within the human body. The particle-size distribution and surface rugosity of the particles have been investigated by small-angle X-ray scattering and dynamic light scattering. Direct Fourier transform as well as a new s...

  17. The evolution and main determinants of productivity in Brazilian electricity distribution 1998-2005. An empirical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Real, Francisco Javier [Fac. CC. Economicas y Empresariales e IUDR - Universidad de La Laguna (ULL), Programa de investigacion Energia y Cambio Climatico Fedea-Abengoa (Spain); Tovar, Beatriz [Dpto. de Analisis Economico Aplicado y EIT - Universidad las Palmas de Gran Canaria (Spain); Iootty, Mariana [UFRRJ Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro (Brazil); De Almeida, Edmar Fagundes; Pinto, Helder Queiroz Jr. [IE-UFRJ Instituto de Economia - Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil)

    2009-03-15

    This paper estimates changes in the productivity of the Brazilian electricity distribution sector using Data Envelopment Analysis (DEA) on a panel of 18 firms from 1998 to 2005. The study decomposes the productivity change of these distribution firms in terms of technical efficiency, scale-efficiency and technical progress. This exercise aims to help the understanding of the main determinants of the evolution of productivity, focusing its relationship with the restructuring process implemented in the 1990s. TFP index records a yearly positive growth rate of 1.3% in the whole period under analysis for all firms. Technical change was the main component behind this evolution, with an average growth of 2.1% per year, while technical efficiency presented a yearly negative performance of - 0.8%. The results prove that, in general terms, the incentives generated in the reform process do not seem to have led the firms to behave in a more efficient manner. (author)

  18. The evolution of biomass-burning aerosol size distributions due to coagulation: dependence on fire and meteorological details and parameterization

    Science.gov (United States)

    Sakamoto, Kimiko M.; Laing, James R.; Stevens, Robin G.; Jaffe, Daniel A.; Pierce, Jeffrey R.

    2016-06-01

    Biomass-burning aerosols have a significant effect on global and regional aerosol climate forcings. To model the magnitude of these effects accurately requires knowledge of the size distribution of the emitted and evolving aerosol particles. Current biomass-burning inventories do not include size distributions, and global and regional models generally assume a fixed size distribution from all biomass-burning emissions. However, biomass-burning size distributions evolve in the plume due to coagulation and net organic aerosol (OA) evaporation or formation, and the plume processes occur on spacial scales smaller than global/regional-model grid boxes. The extent of this size-distribution evolution is dependent on a variety of factors relating to the emission source and atmospheric conditions. Therefore, accurately accounting for biomass-burning aerosol size in global models requires an effective aerosol size distribution that accounts for this sub-grid evolution and can be derived from available emission-inventory and meteorological parameters. In this paper, we perform a detailed investigation of the effects of coagulation on the aerosol size distribution in biomass-burning plumes. We compare the effect of coagulation to that of OA evaporation and formation. We develop coagulation-only parameterizations for effective biomass-burning size distributions using the SAM-TOMAS large-eddy simulation plume model. For the most-sophisticated parameterization, we use the Gaussian Emulation Machine for Sensitivity Analysis (GEM-SA) to build a parameterization of the aged size distribution based on the SAM-TOMAS output and seven inputs: emission median dry diameter, emission distribution modal width, mass emissions flux, fire area, mean boundary-layer wind speed, plume mixing depth, and time/distance since emission. This parameterization was tested against an independent set of SAM-TOMAS simulations and yields R2 values of 0.83 and 0.89 for Dpm and modal width, respectively. The

  19. Debris disk size distributions: steady state collisional evolution with P-R drag and other loss processes

    CERN Document Server

    Wyatt, Mark C; Booth, Mark

    2011-01-01

    We present a new scheme for determining the shape of the size distribution, and its evolution, for collisional cascades of planetesimals undergoing destructive collisions and loss processes like Poynting-Robertson drag. The scheme treats the steady state portion of the cascade by equating mass loss and gain in each size bin; the smallest particles are expected to reach steady state on their collision timescale, while larger particles retain their primordial distribution. For collision-dominated disks, steady state means that mass loss rates in logarithmic size bins are independent of size. This prescription reproduces the expected two phase size distribution, with ripples above the blow-out size, and above the transition to gravity-dominated planetesimal strength. The scheme also reproduces the expected evolution of disk mass, and of dust mass, but is computationally much faster than evolving distributions forward in time. For low-mass disks, P-R drag causes a turnover at small sizes to a size distribution th...

  20. On the evolution of hoarding, risk-taking, and wealth distribution in nonhuman and human populations

    OpenAIRE

    Bergstrom, TC

    2014-01-01

    This paper applies the theory of the evolution of risk-taking in the presence of idiosyncratic and environmental risks to the example of food hoarding by animals and explores implications of the resulting theory for human attitudes toward risk.

  1. Angle-resolved photoemission study of the evolution of band structure and charge density wave properties in RTe3 (R= Y, La, Ce, Sm, Gd, Tb and Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Brouet, V.; Yang, W.L.; Zhou, X.J.; Hussain, Z.; Moore, R.G.; He, R.; Lu, D.H.; Shen, Z.X.; Laverock, J.; Dugdale, S.; Ru, N.; Fisher, I.R.

    2010-02-15

    We present a detailed ARPES investigation of the RTe{sub 3} family, which sets this system as an ideal 'textbook' example for the formation of a nesting driven Charge Density Wave (CDW). This family indeed exhibits the full range of phenomena that can be associated to CDW instabilities, from the opening of large gaps on the best nested parts of Fermi Surface (FS) (up to 0.4eV), to the existence of residual metallic pockets. ARPES is the best suited technique to characterize these features, thanks to its unique ability to resolve the electronic structure in k-space. An additional advantage of RTe{sub 3} is that the band structure can be very accurately described by a simple 2D tight-binding (TB) model, which allows one to understand and easily reproduce many characteristics of the CDW. In this paper, we first establish the main features of the electronic structure, by comparing our ARPES measurements with Linear Muffin-Tin Orbital band calculations. We use this to define the validity and limits of the TB model. We then present a complete description of the CDW properties and, for the first time, of their strong evolution as a function of R. Using simple models, we are able to reproduce perfectly the evolution of gaps in k-space, the evolution of the CDW wave vector with R and the shape of the residual metallic pockets. Finally, we give an estimation of the CDW interaction parameters and find that the change in the electronic density of states n(Ef), due to lattice expansion when different R ions are inserted, has the correct order of magnitude to explain the evolution of the CDW properties.

  2. Collective properties of injection-induced earthquake sequences: 2. Spatiotemporal evolution and magnitude frequency distributions

    Science.gov (United States)

    Dempsey, David; Suckale, Jenny; Huang, Yihe

    2016-05-01

    Probabilistic seismic hazard assessment for induced seismicity depends on reliable estimates of the locations, rate, and magnitude frequency properties of earthquake sequences. The purpose of this paper is to investigate how variations in these properties emerge from interactions between an evolving fluid pressure distribution and the mechanics of rupture on heterogeneous faults. We use an earthquake sequence model, developed in the first part of this two-part series, that computes pore pressure evolution, hypocenter locations, and rupture lengths for earthquakes triggered on 1-D faults with spatially correlated shear stress. We first consider characteristic features that emerge from a range of generic injection scenarios and then focus on the 2010-2011 sequence of earthquakes linked to wastewater disposal into two wells near the towns of Guy and Greenbrier, Arkansas. Simulations indicate that one reason for an increase of the Gutenberg-Richter b value for induced earthquakes is the different rates of reduction of static and residual strength as fluid pressure rises. This promotes fault rupture at lower stress than equivalent tectonic events. Further, b value is shown to decrease with time (the induced seismicity analog of b value reduction toward the end of the seismic cycle) and to be higher on faults with lower initial shear stress. This suggests that faults in the same stress field that have different orientations, and therefore different levels of resolved shear stress, should exhibit seismicity with different b-values. A deficit of large-magnitude events is noted when injection occurs directly onto a fault and this is shown to depend on the geometry of the pressure plume. Finally, we develop models of the Guy-Greenbrier sequence that captures approximately the onset, rise and fall, and southwest migration of seismicity on the Guy-Greenbrier fault. Constrained by the migration rate, we estimate the permeability of a 10 m thick critically stressed basement

  3. On the spatial distribution and evolution of ultrafine particles in Barcelona

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2013-01-01

    Full Text Available Sources and evolution of ultrafine particles were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies, a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 m a.s.l., urban background tower site 80 m a.s.l. during a 4 week period in September–October 2010. Particle number concentrations (N>5 nm are highly correlated with black carbon (BC at all sites only under strong vehicular traffic influences. By contrast, under cleaner atmospheric conditions (low condensation sink, CS such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. Size-resolved aerosol distributions (N10–500 as well as particle number concentrations (N>5 nm allow us to identify three types of nucleation and growth events: (1 a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding urban background area; (2 a regional type event impacting only the regional background area but not the urban agglomerate; (3 an urban type event which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the optimal combination between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated

  4. On the spatial distribution and evolution of ultrafine aerosols in urban air

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2012-07-01

    Full Text Available Sources and evolution of ultrafine particles (<0.1 μ m diameter were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies, a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 μa.s.l., urban background tower site 80 m a.s.l. during a 4 week period in September-October 2010. Particle number concentrations (N>5nm are highly correlated with black carbon (BC at all sites only under strong vehicular traffic influences. By contrast, under clean atmospheric conditions (low condensation sinks, CS such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. This is also evident in the urban background annual mean diurnal trend of N/BC, showing a midday peak in all seasons. Size-resolved aerosol distributions (N10-500 as well as particle number concentrations (N>5nm allow us to identify two types of nucleation and growth events: a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding background area; and an urban type which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the best compromise between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within

  5. On the spatial distribution and evolution of ultrafine particles in Barcelona

    Science.gov (United States)

    Dall'Osto, M.; Querol, X.; Alastuey, A.; O'Dowd, C.; Harrison, R. M.; Wenger, J.; Gómez-Moreno, F. J.

    2013-01-01

    Sources and evolution of ultrafine particles were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 m a.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September-October 2010. Particle number concentrations (N>5 nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under cleaner atmospheric conditions (low condensation sink, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5 nm) allow us to identify three types of nucleation and growth events: (1) a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding urban background area; (2) a regional type event impacting only the regional background area but not the urban agglomerate; (3) an urban type event which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the optimal combination between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC

  6. Inclination angle and braking index evolution of pulsars with plasma-filled magnetosphere: application to high braking index of PSR J1640-4631

    CERN Document Server

    Ekşi, Kazım Yavuz; Çıkıntoğlu, Sercan; Gügercinoğlu, Erbil; Motlagh, Armin Vahdat; Kızıltan, Bülent

    2016-01-01

    The recently discovered rotationally powered pulsar PSR J1640-4631 is the first to have a braking index measured, with high enough precision, to be greater than three. An inclined magnetic rotator in vacuum or plasma would be subject to not only spin-down torque but also to an alignment torque. The vacuum model can address the braking index only for an almost orthogonal rotator which is incompatible with the single peaked pulse profile. We show that the magnetic dipole model with the corotating plasma predicts braking indices between $3-3.25$ and can explain the braking index of $3.15$ for two different inclination angles, $18.5\\pm 3$ degrees and $56 \\pm 4$ degrees. Of these the former is preferred given the pulse profile has a single peak. We infer the change in the inclination angle to be at the rate $-0.23$ degrees per century, three times smaller in absolute value than the rate recently observed from the Crab pulsar.

  7. Measurement of the weak mixing angle and the spin of the gluon from angular distributions in the reaction pp{yields} Z/{gamma}*+X{yields}{mu}{sup +}{mu}{sup -}+X with ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Schmieden, Kristof

    2013-04-15

    The measurement of the effective weak mixing angle with the ATLAS experiment at the LHC is presented. It is extracted from the forward-backward asymmetry in the polar angle distribution of the muons originating from Z boson decays in the reaction pp{yields}Z/{gamma}{sup *}+X{yields} {mu}{sup +}{mu}{sup -}+X. In total 4.7 fb{sup -1} of proton-proton collisions at {radical}(s)=7 TeV are analysed. In addition, the full polar and azimuthal angular distributions are measured as a function of the transverse momentum of the Z/{gamma}{sup *} system and are compared to several simulations as well as recent results obtained in p anti p collisions. Finally, the angular distributions are used to confirm the spin of the gluon using the Lam-Tung relation.

  8. Measurement of the angular distributions in the reaction pp → Z/γ* + X → μ+μ- + X and extraction of the weak mixing angle and the spin of the gluon

    International Nuclear Information System (INIS)

    The measurement of the effective weak mixing angle with the ATLAS experiment at the LHC is presented. It is extracted from the forward-backward asymmetry in the polar angle distribution of the muons originating from Z boson decays in the reaction pp → Z/γ* + X → μ+μ- + X. In total 4.7 fb-1 of proton-proton collisions at √(s) = 7 TeV are analysed. In addition, the full polar and azimuthal angular distributions are measured as a function of the transverse momentum of the Z/γ* system. The comparisons to several simulations as well as recent results obtained in p anti p collisions are presented. Finally, the angular distributions are used to confirm the spin of the gluon using the Lam-Tung relation.

  9. Recent Developments in Perturbative QCD $Q^2$ Evolution of Chiral-Odd Distributions $h_{1}(x,Q^{2})$ and $h_{L}(x,Q^{2})$

    CERN Document Server

    Koike, Y

    1998-01-01

    After reviewing QCD definitions of the chiral-odd spin-dependent parton distributions $h_1(x,Q^2)$ and h_L(x,Q^2), I will summarize the main feature of the recent two results in perturbative QCD: (i) Next-to-leading order $Q^2$ evolution of h_1(x,Q^2). (ii) Leading order Q^2 evolution of the twist-3 distribution h_L(x,Q^2) and the universal simplification of the Q^2 evolution of all the twist-3 distributions in the large N_c limit.

  10. Numerical investigation on residual stress distribution and evolution during multipass narrow gap welding of thick-walled stainless steel pipes

    International Nuclear Information System (INIS)

    Research highlights: → We performed pass-by-pass simulation of stresses for welding of thick-walled pipes. → The distributions and evolution of the residual stresses are demonstrated. → After the groove is filled to a height, the through-wall stress is almost unchanged. - Abstracts: The detailed pass-by-pass finite element (FE) simulation is presented to investigate the residual stresses in narrow gap multipass welding of pipes with a wall thickness of 70 mm and 73 weld passes. The simulated residual stress on the outer surface is validated with the experimental one. The distribution and evolution of the through-wall residual stresses are demonstrated. The investigated results show that the residual stresses on the outer and inner surfaces are tensile in the weld zone and its vicinity. The through-wall axial residual stresses at the weld center line and the HAZ line demonstrate a distribution of bending type. The through-wall hoop residual stress within the weld is mostly tensile. After the groove is filled to a certain height, the peak tensile stresses and the stress distribution patterns for both axial and hoop stresses remain almost unchanged.

  11. Asteroid age distributions determined by space weathering and collisional evolution models

    OpenAIRE

    Willman, Mark; Jedicke, Robert

    2010-01-01

    We provide evidence of consistency between the dynamical evolution of main belt asteroids and their color evolution due to space weathering. The dynamical age of an asteroid's surface \\citep{bib.bot05a,bib.nes05} is the time since its last catastrophic disruption event which is a function of the object's diameter. The age of an S-complex asteroid's surface may also be determined from its color using a space weathering model \\citep[e.g.][]{bib.wil10,bib.jed04,bib.wil08,bib.mar06}. We used a sa...

  12. Bayesian Inference of the Evolution of a Phenotype Distribution on a Phylogenetic Tree

    Science.gov (United States)

    Ansari, M. Azim; Didelot, Xavier

    2016-01-01

    The distribution of a phenotype on a phylogenetic tree is often a quantity of interest. Many phenotypes have imperfect heritability, so that a measurement of the phenotype for an individual can be thought of as a single realization from the phenotype distribution of that individual. If all individuals in a phylogeny had the same phenotype distribution, measured phenotypes would be randomly distributed on the tree leaves. This is, however, often not the case, implying that the phenotype distribution evolves over time. Here we propose a new model based on this principle of evolving phenotype distribution on the branches of a phylogeny, which is different from ancestral state reconstruction where the phenotype itself is assumed to evolve. We develop an efficient Bayesian inference method to estimate the parameters of our model and to test the evidence for changes in the phenotype distribution. We use multiple simulated data sets to show that our algorithm has good sensitivity and specificity properties. Since our method identifies branches on the tree on which the phenotype distribution has changed, it is able to break down a tree into components for which this distribution is unique and constant. We present two applications of our method, one investigating the association between HIV genetic variation and human leukocyte antigen and the other studying host range distribution in a lineage of Salmonella enterica, and we discuss many other potential applications. PMID:27412711

  13. The Evolution of Frequency Distributions: Relating Regularization to Inductive Biases through Iterated Learning

    Science.gov (United States)

    Reali, Florencia; Griffiths, Thomas L.

    2009-01-01

    The regularization of linguistic structures by learners has played a key role in arguments for strong innate constraints on language acquisition, and has important implications for language evolution. However, relating the inductive biases of learners to regularization behavior in laboratory tasks can be challenging without a formal model. In this…

  14. Repetitive Sequences in Plant Nuclear DNA:Types, Distribution, Evolution and Function

    Institute of Scientific and Technical Information of China (English)

    Shweta Mehrotra; Vinod Goyal

    2014-01-01

    Repetitive DNA sequences are a major component of eukaryotic genomes and may account for up to 90% of the genome size. They can be divided into minisatellite, microsatellite and satellite sequences. Satellite DNA sequences are considered to be a fast-evolving component of eukaryotic genomes, comprising tandemly-arrayed, highly-repetitive and highly-conserved monomer sequences. The monomer unit of satellite DNA is 150-400 base pairs (bp) in length. Repetitive sequences may be species- or genus-specific, and may be centromeric or subtelomeric in nature. They exhibit cohesive and concerted evolution caused by molecular drive, leading to high sequence homogeneity. Repetitive sequences accumulate variations in sequence and copy number during evolution, hence they are important tools for taxonomic and phylogenetic studies, and are known as‘‘tuning knobs’’ in the evolution. Therefore, knowledge of repetitive sequences assists our understanding of the organization, evolution and behavior of eukaryotic genomes. Repetitive sequences have cytoplasmic, cellular and developmental effects and play a role in chromosomal recombination. In the post-genomics era, with the introduction of next-generation sequencing tech-nology, it is possible to evaluate complex genomes for analyzing repetitive sequences and decipher-ing the yet unknown functional potential of repetitive sequences.

  15. Structural architecture and palaeofluid evolution of low-angle extensional fault systems cutting through carbonate rocks within the brittle crust. The case study of the Tellaro Detachment, Northern Apennines (Italy).

    Science.gov (United States)

    Clemenzi, Luca; Storti, Fabrizio; Balsamo, Fabrizio; Molli, Giancarlo; Ellam, Rob; Muchez, Philippe; Swennen, Rudy

    2014-05-01

    The Tellaro Detachment is an exhumed low-angle extensional fault zone exposed in the internal portion of the Northern Apennines thrust wedge. It developed at shallow structural levels within the brittle crust, and mainly affected the carbonate-dominated Late Triassic to early Early Miocene non-metamorphic Tuscan succession. The three-dimensional geometry of the Tellaro Detachment has been investigated through detailed structural mapping and restoration of the superimposed deformations, while appropriate exposure allowed for accurate damage zone characterization. Pressure-depth conditions and palaeofluid evolution of the fault system have been studied through microstructural, mineralogical, petrographic, fluid inclusion and stable isotope analysis of fault rocks and fault-related dolomite and calcite veins. Abundant fluid circulation characterized the fault zone, with development of metric- to decametric-scale dolomitic bodies, abundant pressure solution, and veining. Dolomitic bodies are discordant to bedding and typically overly the main low-angle fault segments; they are brecciated and crosscut by the subsidiary high-angle faults. Dolomite veins are only observed in dolomitic host rocks. They are generally oriented perpendicular to the tectonic transport direction and formed at about 175°C and 5.2 km depth. Stable isotope signature and elevated salinity suggest precipitation from a rock-buffered fluid. Syntectonic calcite veins with variable orientations are well developed in the fault damage zones, and characterized by multiple generations of infillings. Crosscutting relationships between differently oriented veins are not systematic in damage zones and the different calcite generations do not have any preferred orientations. Furthermore, short and irregularly shaped veins characterize the footwall damage zone in the proximity of the major low-angle fault segments. Fluid inclusion microthermometry indicates that different veins formed at different temperature

  16. Effect of elbow flexion angles on stress distribution of the proximal ulnar and radius bones under a vertical load: measurement using resistance strain gauges

    OpenAIRE

    Rao, Zhi-Tao; Yuan, Feng; Li, Bing; Ma, Ning

    2014-01-01

    Objectives This study aimed to explore the surface stress at the proximal ends of the ulna and radius at different elbow flexion angles using the resistance strain method. Methods Eight fresh adult cadaveric elbows were tested. The forearms were fixed in a neutral position. Axial load increment experiments were conducted at four different elbow flexion angles (0°, 15°, 30°, and 45°). Surface stain was measured at six sites (tip, middle, and base of the coronoid process; back ulnar notch; olec...

  17. Effects of Crowding and Environment on the Evolution of Conformational Ensembles of the Multi-Stimuli-Responsive Intrinsically Disordered Protein, Rec1-Resilin: A Small-Angle Scattering Investigation.

    Science.gov (United States)

    Balu, Rajkamal; Mata, Jitendra P; Knott, Robert; Elvin, Christopher M; Hill, Anita J; Choudhury, Namita R; Dutta, Naba K

    2016-07-14

    In this study, we explore the overall structural ensembles and transitions of a biomimetic, multi-stimuli-responsive, intrinsically disordered protein (IDP), Rec1-resilin. The structural transition of Rec1-resilin with change in molecular crowding and environment is evaluated using small-angle neutron scattering and small-angle X-ray scattering. The quantitative analyses of the experimental scattering data using a combination of computational models allowed comprehensive description of the structural evolution, organization, and conformational ensembles of Rec1-resilin in response to the changes in concentration, pH, and temperature. Rec1-resilin in uncrowded solutions demonstrates the equilibrium intrinsic structure quality of an IDP with radius of gyration Rg ∼ 5 nm, and a scattering function for the triaxial ellipsoidal model best fit the experimental dataset. On crowding (increase in concentration >10 wt %), Rec1-resilin molecules exert intermolecular repulsive force of interaction, the Rg value reduces with a progressive increase in concentration, and molecular chains transform from a Gaussian coil to a fully swollen coil. It is also revealed that the structural organization of Rec1-resilin dynamically transforms from a rod (pH 2) to coil (pH 4.8) and to globular (pH 12) as a function of pH. The findings further support the temperature-triggered dual-phase-transition behavior of Rec1-resilin, exhibiting rod-shaped structural organization below the upper critical solution temperature (∼4 °C) and a large but compact structure above the lower critical solution temperature (∼75 °C). This work attempted to correlate unusual responsiveness of Rec1-resilin to the evolution of conformational ensembles. PMID:27281267

  18. Evolution of the size distribution of oil droplets on a water surface: Setup, image processing, and scaling laws

    OpenAIRE

    de Maeyer, J.

    2015-01-01

    In this thesis, I describe my work towards a novel experiment to study the dynamics of oil droplets on water. It allows following the evolution of the droplet size distribution during a coalescence process with superb statistics. Every experiment run involves more than 20,000 initial droplets coalescing into a few hundred within four to six hours, with droplet sizes ranging from 0.01 cm2 to 1,000 cm2. Data acquisition is built around an LED light source and a shadow image method that exploits...

  19. Time-evolution of the ion velocity distribution function in the discharge of a Hall effect thruster

    OpenAIRE

    Mazouffre, S.; Gawron, D.; N. Sadeghi

    2009-01-01

    The temporal characteristics of the Xe$^+$ ion axial Velocity Distribution Function (VDF) were recorded in the course of low-frequency discharge current oscillations ($\\sim$~14 kHz) of the 5 kW-class PPS$\\circledR$X000 Hall thruster. The evolution in time of the ion axial velocity component is monitored by means of a laser induced fluorescence diagnostic tool with a time resolution of 100 ns. As the number of fluorescence photons is very low during such a short time period, a hom-made pulse-c...

  20. Understanding the evolution of poverty and income distribution in Mexico, 1992-2008

    OpenAIRE

    Lopez-Aguilera, Estela

    2011-01-01

    This thesis documents and investigates the evolution of poverty and inequality in Mexico between 1992 and 2008. It applies best practice techniques and in doing so, aims to reconcile the differences that emerge between studies that use the same data. It also investigates and identifies some of the underlying processes and factors driving high levels of poverty and inequality; mapping these on to periods of crisis, reform and recovery and also to changes in the underlying population characteri...

  1. The evolution of control and distribution of adaptive mutations in a metabolic pathway.

    Science.gov (United States)

    Wright, Kevin M; Rausher, Mark D

    2010-02-01

    In an attempt to understand whether it should be expected that some genes tend to be used disproportionately often by natural selection, we investigated two related phenomena: the evolution of flux control among enzymes in a metabolic pathway and properties of adaptive substitutions in pathway enzymes. These two phenomena are related by the principle that adaptive substitutions should occur more frequently in enzymes with greater flux control. Predicting which enzymes will be preferentially involved in adaptive evolution thus requires an evolutionary theory of flux control. We investigated the evolution of enzyme control in metabolic pathways with two models of enzyme kinetics: metabolic control theory (MCT) and Michaelis-Menten saturation kinetics (SK). Our models generate two main predictions for pathways in which reactions are moderately to highly irreversible: (1) flux control will evolve to be highly unequal among enzymes in a pathway and (2) upstream enzymes evolve a greater control coefficient then those downstream. This results in upstream enzymes fixing the majority of beneficial mutations during adaptive evolution. Once the population has reached high fitness, the trend is reversed, with the majority of neutral/slightly deleterious mutations occurring in downstream enzymes. These patterns are the result of three factors (the first of these is unique to the MCT simulations while the other two seem to be general properties of the metabolic pathways): (1) the majority of randomly selected, starting combinations of enzyme kinetic rates generate pathways that possess greater control for the upstream enzymes compared to downstream enzymes; (2) selection against large pools of intermediate substrates tends to prevent majority control by downstream enzymes; and (3) equivalent mutations in enzyme kinetic rates have the greatest effect on flux for enzymes with high levels of flux control, and these enzymes will accumulate adaptive substitutions, strengthening their

  2. Brown fat distribution in the chest wall of infants - normal appearance, distribution and evolution on CT scans of the chest

    International Nuclear Information System (INIS)

    While reviewing chest CT scans of infants, we repeatedly observed hyperdense enhancing tissue in the chest wall that is not well described in radiology literature. This study was undertaken to describe the imaging features of this tissue in chest walls of infants. CT scans of the chest conducted on all infants between April 2008 and October 2009 were retrospectively reviewed. CT studies with any deviation from normal radiation or contrast dose or those with chest wall anatomical distortion were excluded. One hundred eighty-eight infants were scanned, with 202 MDCTs, of which 180 (89.1%) received contrast agent. Fifty-four of 180 (30%) cases revealed focal areas of hyperdensity in various locations. All positive cases ranged between 2 days and 9 months of age. The areas of distribution of hyperdensity had excellent correlation with known areas of brown fat in the chest wall, known from nuclear medicine studies, and hence we concluded these to represent the same. Brown fat in the chest wall can be seen as enhancing tissue on contrast CT scans done on infants. This is a normal morphological component with the brown fat converting to normal fat. It is important to recognize it in the chest wall of infants to avoid misinterpretation. (orig.)

  3. Brown fat distribution in the chest wall of infants - normal appearance, distribution and evolution on CT scans of the chest

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Priya; Babyn, Paul S.; Shammas, Amer; Miller, Stephen F. [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada)

    2011-08-15

    While reviewing chest CT scans of infants, we repeatedly observed hyperdense enhancing tissue in the chest wall that is not well described in radiology literature. This study was undertaken to describe the imaging features of this tissue in chest walls of infants. CT scans of the chest conducted on all infants between April 2008 and October 2009 were retrospectively reviewed. CT studies with any deviation from normal radiation or contrast dose or those with chest wall anatomical distortion were excluded. One hundred eighty-eight infants were scanned, with 202 MDCTs, of which 180 (89.1%) received contrast agent. Fifty-four of 180 (30%) cases revealed focal areas of hyperdensity in various locations. All positive cases ranged between 2 days and 9 months of age. The areas of distribution of hyperdensity had excellent correlation with known areas of brown fat in the chest wall, known from nuclear medicine studies, and hence we concluded these to represent the same. Brown fat in the chest wall can be seen as enhancing tissue on contrast CT scans done on infants. This is a normal morphological component with the brown fat converting to normal fat. It is important to recognize it in the chest wall of infants to avoid misinterpretation. (orig.)

  4. Molecular and morphological systematics of the Ellisellidae (Coelenterata: Octocorallia): Parallel evolution in a globally distributed family of octocorals

    KAUST Repository

    Bilewitch, Jaret P.

    2014-04-01

    The octocorals of the Ellisellidae constitute a diverse and widely distributed family with subdivisions into genera based on colonial growth forms. Branching patterns are repeated in several genera and congeners often display region-specific variations in a given growth form. We examined the systematic patterns of ellisellid genera and the evolution of branching form diversity using molecular phylogenetic and ancestral morphological reconstructions. Six of eight included genera were found to be polyphyletic due to biogeographical incompatibility with current taxonomic assignments and the creation of at least six new genera plus several reassignments among existing genera is necessary. Phylogenetic patterns of diversification of colony branching morphology displayed a similar transformation order in each of the two primary ellisellid clades, with a sea fan form estimated as the most-probable common ancestor with likely origins in the Indo-Pacific region. The observed parallelism in evolution indicates the existence of a constraint on the genetic elements determining ellisellid colonial morphology. However, the lack of correspondence between levels of genetic divergence and morphological diversity among genera suggests that future octocoral studies should focus on the role of changes in gene regulation in the evolution of branching patterns. © 2014 Elsevier Inc.

  5. Evolution of the ATLAS Distributed Computing during the LHC long shutdown

    CERN Document Server

    Campana, S; The ATLAS collaboration

    2013-01-01

    The ATLAS Distributed Computing project (ADC) was established in 2007 to develop and operate a framework, following the ATLAS computing model, to enable data storage, processing and bookkeeping on top of the WLCG distributed infrastructure. ADC development has always been driven by operations and this contributed to its success. The system has fulfilled the demanding requirements of ATLAS, daily consolidating worldwide up to 1PB of data and running more than 1.5 million payloads distributed globally, supporting almost one thousand concurrent distributed analysis users. Comprehensive automation and monitoring minimized the operational manpower required. The flexibility of the system to adjust to operational needs has been important to the success of the ATLAS physics program. The LHC shutdown in 2013-2015 affords an opportunity to improve the system in light of operational experience and scale it to cope with the demanding requirements of 2015 and beyond, most notably a much higher trigger rate and event pileu...

  6. Evolution of the ATLAS Distributed Computing system during the LHC Long shutdown

    CERN Document Server

    Campana, S; The ATLAS collaboration

    2014-01-01

    The ATLAS Distributed Computing project (ADC) was established in 2007 to develop and operate a framework, following the ATLAS computing model, to enable data storage, processing and bookkeeping on top of the WLCG distributed infrastructure. ADC development has always been driven by operations and this contributed to its success. The system has fulfilled the demanding requirements of ATLAS, daily consolidating worldwide up to 1PB of data and running more than 1.5 million payloads distributed globally, supporting almost one thousand concurrent distributed analysis users. Comprehensive automation and monitoring minimized the operational manpower required. The flexibility of the system to adjust to operational needs has been important to the success of the ATLAS physics program. The LHC shutdown in 2013-2015 affords an opportunity to improve the system in light of operational experience and scale it to cope with the demanding requirements of 2015 and beyond, most notably a much higher trigger rate and event pileu...

  7. Large shield volcanos on Venus: The effect of neutral buoyancy zone development on evolution and altitude distribution

    Science.gov (United States)

    Keddie, S.; Head, James W., III

    1992-01-01

    The Magellan mission to Venus has emphasized the importance of volcanism in shaping the surface of the planet. Volcanic plains make up 80 percent of the terrain and hundreds of regions of localized eruptions have been identified. Large volcanos, defined as edifices with diameters greater than 100 km, are the sites of some of the most voluminous eruptions. Head et al. have identified 158 of these structures. Their spatial distribution is neither random nor arranged in linear chains as on the Earth; large volcanos on Venus are concentrated in two large, near-equatorial clusters that are also the site of many other forms of volcanic activity. The set of conditions that must be met on Venus that controls the change from widespread, distributed volcanism to focused, shield-building volcanism is not well understood. Future studies of transitional features will help to address this problem. It is likely, however, that the formation and evolution of a neutral buoyancy zone (NBZ) plays an important role in both determining the style of the volcanism and the development of the volcanic feature once it has begun to erupt. Head and Wilson have suggested that the high surface pressure on Venus may inhibit volatile exsolution, which may influence the density distribution of the upper crust and hence control the nature and location of a NBZ. The extreme variations in pressure with elevation may result in significantly different characteristics of such a NBZ at different locations on the planet. In order to test these ideas regarding the importance of NBZ development in the evolution of a large shield and to determine the style of volcanism, three large volcanos that occur at different basal elevations were examined and the distribution of large volcanos as a function of altitude was determined.

  8. Phase Transition in the Genome Evolution Favors Nonrandom Distribution of Genes on Chromosomes

    Science.gov (United States)

    Kowalski, Jakub; Waga, Wojciech; Zawierta, Marta; Cebrat, Stanisław

    We have used the Monte Carlo-based computer models to show that selection pressure could affect the distribution of recombination hotspots along the chromosome. Close to the critical crossover rate, where genomes may switch between the Darwinian purifying selection or complementation of haplotypes, the distribution of recombination events and the force of selection exerted on genes affect the structure of chromosomes. The order of expression of genes and their location on chromosome may decide about the extinction or survival of competing populations.

  9. An end to endless forms: epistasis, phenotype distribution bias, and nonuniform evolution.

    Directory of Open Access Journals (Sweden)

    Elhanan Borenstein

    2008-10-01

    Full Text Available Studies of the evolution of development characterize the way in which gene regulatory dynamics during ontogeny constructs and channels phenotypic variation. These studies have identified a number of evolutionary regularities: (1 phenotypes occupy only a small subspace of possible phenotypes, (2 the influence of mutation is not uniform and is often canalized, and (3 a great deal of morphological variation evolved early in the history of multicellular life. An important implication of these studies is that diversity is largely the outcome of the evolution of gene regulation rather than the emergence of new, structural genes. Using a simple model that considers a generic property of developmental maps-the interaction between multiple genetic elements and the nonlinearity of gene interaction in shaping phenotypic traits-we are able to recover many of these empirical regularities. We show that visible phenotypes represent only a small fraction of possibilities. Epistasis ensures that phenotypes are highly clustered in morphospace and that the most frequent phenotypes are the most similar. We perform phylogenetic analyses on an evolving, developmental model and find that species become more alike through time, whereas higher-level grades have a tendency to diverge. Ancestral phenotypes, produced by early developmental programs with a low level of gene interaction, are found to span a significantly greater volume of the total phenotypic space than derived taxa. We suggest that early and late evolution have a different character that we classify into micro- and macroevolutionary configurations. These findings complement the view of development as a key component in the production of endless forms and highlight the crucial role of development in constraining biotic diversity and evolutionary trajectories.

  10. Modeling the evolution and distribution of the frequency's second derivative and the braking index of pulsar spin

    International Nuclear Information System (INIS)

    We model the evolution of the spin frequency's second derivative v.. and the braking index n of radio pulsars with simulations within the phenomenological model of their surface magnetic field evolution, which contains a long-term power-law decay modulated by short-term oscillations. For the pulsar PSR B0329+54, a model with three oscillation components can reproduce its v.. variation. We show that the “averaged” n is different from the instantaneous n, and its oscillation magnitude decreases abruptly as the time span increases, due to the “averaging” effect. The simulated timing residuals agree with the main features of the reported data. Our model predicts that the averaged v.. of PSR B0329+54 will start to decrease rapidly with newer data beyond those used in Hobbs et al. We further perform Monte Carlo simulations for the distribution of the reported data in |v..| and |n| versus characteristic age τC diagrams. It is found that the magnetic field oscillation model with decay index α = 0 can reproduce the distributions quite well. Compared with magnetic field decay due to the ambipolar diffusion (α = 0.5) and the Hall cascade (α = 1.0), the model with no long term decay (α = 0) is clearly preferred for old pulsars by the p-values of the two-dimensional Kolmogorov-Smirnov test. (paper)

  11. A lattice determination of gA and left angle x right angle from overlap fermions

    International Nuclear Information System (INIS)

    We present results for the nucleon's axial charge gA and the first moment left angle x right angle of the unpolarized parton distribution function from a simulation of quenched overlap fermions. (orig.)

  12. Determination of the relations governing the evolution of the standard deviations of the distribution of pollution

    International Nuclear Information System (INIS)

    An original concept on the difference of behaviour of the high frequency (small-scale) and low frequency (large-scale) atmospheric turbulence relatively to the mean wind speed has been introduced. Through a dimensional analysis based on TAYLOR's formulation, it has been shown that the parameter of the atmospheric dispersion standard-deviations was the travel distance near the source, and the travel time far from the source. Using hypotheses on the energy spectrum in the atmosphere, a numerical application has made it possible to quantify the evolution of the horizontal standard deviation for different mean wind speeds between 0,2 and 10m/s. The areas of validity of the parameter (travel distance or travel time) are clearly shown. The first one is confined in the near field and is all the smaller if the wind speed decreases. For t > 5000s, the dependence on the wind speed of the horizontal standard-deviation expressed in function of the travel time becomes insignificant. The horizontal standard-deviation is only function of the travel time. Results are compared with experimental data obtained in the atmosphere. The similar evolution of the calculated and experimental curves confirms the validity of the hypothesis and input data in calculation. This study can be applied to radioactive effluents transport in the atmosphere

  13. THE GLUON DISTRIBUTION AT SMALL x OBTAINED FROM A UNIFIED EVOLUTION EQUATION.

    OpenAIRE

    Kwiecinski, J.; Martin, A. D.(Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE, Durham, UK); Sutton, P. J.

    1995-01-01

    We solve a unified integral equation to obtain the $x, Q_T$ and $Q$ dependence of the gluon distribution of a proton in the small $x$ regime; where $x$ and $Q_T$ are the longitudinal momentum fraction and the transverse momentum of the gluon probed at a scale $Q$. The equation generates a gluon with a steep $x^{- \\lambda}$ behaviour, with $\\lambda \\sim 0.5$, and a $Q_T$ distribution which broadens as $x$ decreases. We compare our solutions with, on the one hand, those that we obtain using the...

  14. Back-to-back gridded ionization detector technique for the determination of fragment angle and its use for the measurement of neutron angular distributions in 235U(nth,f)

    International Nuclear Information System (INIS)

    A back-to-back gridded ionization chamber was used to measure the prompt neutron angular distributions after determining the fission fragment angle with incorporation of energy loss correction in the target and backing material. The correspondence of the ratio (Vg/Vc) of the grid pulse height to the collector pulse height with cos θ is made use of to derive energy loss corrected Vg and Vc values. The fragment angle is obtained from the corrected grid pulse heights after determining the calibration constants for 0 and 90 emission angles as a function of energy and mass of the fission fragments. An angular resolution of 2 to 3 [FWHM]for each fragment could be obtained over a large angular range on each side of the ionization chamber. The chamber was used along with a NE213 neutron detector to measure the angular distributions of the prompt neutrons emitted in the thermal neutron induced fission of 235U, and results of these are reported as an illustration of the present method. (orig.)

  15. A determination of the thick disk chemical abundance distribution: Implications for galaxy evolution

    Science.gov (United States)

    Gilmore, Gerard; Wyse, Rosemary F. G.; Jones, Bryn J.

    1995-01-01

    We present a determination of the thick disk iron abundance distribution obtained from an in situ sample of F/G stars. These stars are faint, 15 less than or approximately = V less than or approximately = 18, selected on the basis of color, being a subset of the larger survey of Gilmore and Wyse designed to determine the properties of the stellar populations several kiloparsecs from the Sun. The fields studied in the present paper probe the iron abundance distribution of the stellar populations of the galaxy at 500-3000 pc above the plane, at the solar Galactocentric distance. The derived chemical abundance distributions are consistent with no metallicity gradients in the thick disk over this range of vertical distance, and with an iron abundance distribution for the thick disk that has a peak at -0.7 dex. The lack of a vertical gradient argues against slow, dissipational settling as a mechanism for the formation of the thick disk. The photometric and metallicity data support a turn-off of the thick disk that is comparable in age to the metal-rich globular clusters, or greater than or approximately = 12 Gyr, and are consistent with a spread to older ages.

  16. Evolution of reinforcement distribution in Al-B4C composites during accumulative roll bonding

    International Nuclear Information System (INIS)

    Highlights: → ARB developed a nanostructure in the matrix of the Al-B4C composite. → An improvement in the reinforcement distribution was found by increasing ARB passes. → By progression of ARB from one to seven passes, hardness increased from 60 to 82 HV. -- Abstract: The distribution of reinforcement particles in the matrix of a composite is one of the most important microstructural features affecting properties. In this study, nanostructured Al-B4C composite sheets were processed by accumulative roll bonding (ARB), and the effect of the number of ARB cycles on the distribution of the B4C particles in the Al matrix was evaluated. From optical microscopic studies accompanied by the radial distribution function analysis, it was realized that the microstructure uniformity is improved by increasing the number of ARB cycles. It was in good agreement with bulk hardness measurements in which the standard deviation of the hardness values was decreased by progression of the ARB process. In addition, the X-ray diffraction peak profile analysis revealed that the area weighted mean crystallite size of the Al matrix decreases to the nanometric scale (114 nm) after seven ARB cycles.

  17. Canonical studies of the cluster distribution, dynamical evolution, and critical temperature in nuclear multifragmentation processes

    International Nuclear Information System (INIS)

    Partition functions for a canonical and microcanonical ensemble are developed which are then used to describe various properties of excited hadronic systems. Relating multinomial coefficients to a generating function of these partition functions, it is shown that the average value of various moments of cluster sizes are of a quite simple form in terms of canonical partition functions. Specific applications of the results are to partitioning problems as in the partitioning of nucleons into clusters arising from a nuclear collision and to branching processes as in Furry branching. The underlying dynamical evolution of a system is studied by parametrizing the multinomial variables of the theory. A Fokker-Planck equation can be obtained from these evolutionary equations. By relating the parameters and variables of the theory to thermodynamic variables, the thermal properties of excited hadronic systems are studied

  18. The cross-section dividing method and the simultaneous distribution between the deflection angle and the spatial displacement for charged particles penetrating through matters

    International Nuclear Information System (INIS)

    Although Moliere theory is less accurate than Goudsmit-Saunderson theory due to the small angle approximation, there still remain many superior aspects of Moliere theory to the latter. Some problems are yet too difficult to solve through Goudsmit-Saunderon theory itself due to our mathematical insufficiencies and require Moliere and other results. Some Moliere results are still valuable in solving problems under Goudsmit-Saunderson theory. Some Moliere results will be useful in examining accuracy of the results derived through Goudsmit-Saunderson theory. We will look back and look forward again the significance of Moliere theory and Moliere results. (author)

  19. NUMERICAL MODEL TO PREDICT DISTRIBUTION AND EVOLUTION OF SUSPENDED SEDIMENT TRANSPORT IN A DAM RESERVOIR

    Directory of Open Access Journals (Sweden)

    Nacima Hadjrabia Melboucy

    2012-07-01

    Full Text Available Sediment transport in waterways towards dam reservoirs affects their life span by reducing their storage capacity and burying their bottom control gates and equipments. In this paper, a sediment distribution computed model is presented. It is developed by solving the bi-dimensional horizontal free surface flow ‘Saint Venant equations’ and the depth-averaged mass conservation equation of suspended sediment transport. For that, two explicit finite difference schemes are applied; Mac Cormack for solving hydrodynamic system and upwind for the transport equation. Discretization of 2D equations is done with a rectangular fully dense grid. The developed model is applied to predict water surface elevation, horizontal components of depth-averaged velocity and sediment transport distribution in Gargar dam reservoir. Computed values are compared with those resulting from Mike21 program and show good agreement with it.

  20. Predictions of Gene Family Distributions in Microbial Genomes: Evolution by Gene Duplication and Modification

    International Nuclear Information System (INIS)

    A universal property of microbial genomes is the considerable fraction of genes that are homologous to other genes within the same genome. The process by which these homologues are generated is not well understood, but sequence analysis of 20 microbial genomes unveils a recurrent distribution of gene family sizes. We show that a simple evolutionary model based on random gene duplication and point mutations fully accounts for these distributions and permits predictions for the number of gene families in genomes not yet complete. Our findings are consistent with the notion that a genome evolves from a set of precursor genes to a mature size by gene duplications and increasing modifications. (c) 2000 The American Physical Society

  1. Distributed energy-balance modeling of snow-cover evolution and melt in rugged terrain: Tobacco Root Mountains, Montana, USA

    Science.gov (United States)

    Letsinger, S.L.; Olyphant, G.A.

    2007-01-01

    A distributed energy-balance model was developed for simulating snowpack evolution and melt in rugged terrain. The model, which was applied to a 43-km2 watershed in the Tobacco Root Mountains, Montana, USA, used measured ambient data from nearby weather stations to drive energy-balance calculations and to constrain the model of Liston and Sturm [Liston, G.E., Sturm, M., 1998. A snow-transport model for complex terrain. Journal of Glaciology 44 (148), 498-516] for calculating the initial snowpack thickness. Simulated initial snow-water equivalent ranged between 1 cm and 385 cm w.e. (water equivalent) with high values concentrated on east-facing slopes below tall summits. An interpreted satellite image of the snowcover distribution on May 6, 1998, closely matched the simulated distribution with the greatest discrepancy occurring in the floor of the main trunk valley. Model simulations indicated that snowmelt commenced early in the melt season, but rapid meltout of snow cover did not occur until after the average energy balance of the entire watershed became positive about 45 days into the melt season. Meltout was fastest in the lower part of the watershed where warmer temperatures and tree cover enhanced the energy income of the underlying snow. An interpreted satellite image of the snowcover distribution on July 9, 1998 compared favorably with the simulated distribution, and melt curves for modeled canopy-covered cells mimicked the trends measured at nearby snow pillow stations. By the end of the simulation period (August 3), 28% of the watershed remained snow covered, most of which was concentrated in the highest parts of the watershed where initially thick accumulations had been shaded by surrounding summits. The results of this study provide further demonstration of the critical role that topography plays in the timing and magnitude of snowmelt from high mountain watersheds. ?? 2006 Elsevier B.V. All rights reserved.

  2. NUMERICAL MODEL TO PREDICT DISTRIBUTION AND EVOLUTION OF SUSPENDED SEDIMENT TRANSPORT IN A DAM RESERVOIR

    OpenAIRE

    Nacima Hadjrabia Melboucy; Malek Bouhadef

    2012-01-01

    Sediment transport in waterways towards dam reservoirs affects their life span by reducing their storage capacity and burying their bottom control gates and equipments. In this paper, a sediment distribution computed model is presented. It is developed by solving the bi-dimensional horizontal free surface flow ‘Saint Venant equations’ and the depth-averaged mass conservation equation of suspended sediment transport. For that, two explicit finite difference schemes are applied; Mac Cormack for...

  3. Analogous reserve distribution and tissue characteristics in quinoa and grass seeds suggest convergent evolution

    OpenAIRE

    Burrieza, Hernán P.; López-Fernández, María P.; Maldonado, Sara

    2014-01-01

    Quinoa seeds are highly nutritious due to the quality of their proteins and lipids and the wide range of minerals and vitamins they store. Three compartments can be distinguished within the mature seed: embryo, endosperm, and perisperm. The distribution of main storage reserves is clearly different in those areas: the embryo and endosperm store proteins, lipids, and minerals, and the perisperm stores starch. Tissues equivalent (but not homologous) to those found in grasses can be identified i...

  4. Recurrent evolution of host-specialized races in a globally distributed parasite

    OpenAIRE

    McCoy, Karen D.; Chapuis, Elodie; Tirard, Claire; Boulinier, Thierry; Michalakis, Yannis; Bohec, Céline Le; Maho, Yvon Le; Gauthier-Clerc, Michel

    2005-01-01

    The outcome of coevolutionary interactions is predicted to vary across landscapes depending on local conditions and levels of gene flow, with some populations evolving more extreme specializations than others. Using a globally distributed parasite of colonial seabirds, the tick Ixodes uriae, we examined how host availability and geographic isolation influences this process. In particular, we sampled ticks from 30 populations of six different seabird host species, three in the Southern Hemisph...

  5. On the evolution of nanocluster size distribution in a nanocluster aggregation source

    OpenAIRE

    Turkin, A.A.; Dutka, M.V.; Pei, Y.T.; Vainchtein, David; De Hosson, J.Th.M.

    2012-01-01

    This paper presents a detailed model of cluster formation from a supersaturated atomic vapor in an inert buffer gas. The population balance equations for the cluster size distribution are based on the Smoluchowski coagulation equation and take into account (i) convective diffusion of clusters, (ii) cluster loss to walls of an aggregation chamber, and (iii) formation of fractal-like aggregates. The model predictions are confronted to experimental observations, and they agree with experimental ...

  6. The Cosmic Evolution of the Metallicity Distribution of Ionized Gas Traced by Lyman Limit Systems

    CERN Document Server

    Lehner, Nicolas; Howk, J Christopher; Prochaska, J Xavier; Fumagalli, Michele

    2016-01-01

    We present the first results from our KODIAQ Z survey aimed to determine the metallicity distribution and physical properties of the partial and full Lyman limit systems (pLLSs and LLSs; 16.22, which probe gas in the interface regions between the intergalactic medium and galaxies. We study 31 HI-selected pLLSs and LLSs at 2.3distribution function (MDF) of the pLLSs/LLSs at 2.3distribution peaking at [X/H]=-2, in contrast to the bimodal MDF seen at z<1. There is a substantial fraction (20-45%) of pLLSs/LLSs with metallicities well below those of damped Lyman alpha absorbers (DLAs) at any given z, and this fraction remains relatively constant from z<1 to z~2-4. There is therefore a reservoir of metal-poor cool gas at all z that ma...

  7. Influence of spatiotemporally distributed irradiance data input on temperature evolution in parabolic trough solar field simulations

    Science.gov (United States)

    Bubolz, K.; Schenk, H.; Hirsch, T.

    2016-05-01

    Concentrating solar field operation is affected by shadowing through cloud movement. For line focusing systems the impact of varying irradiance has been studied before by several authors with simulations of relevant thermodynamics assuming spatially homogeneous irradiance or using artificial test signals. While today's simulation capabilities allow more and more a higher spatiotemporal resolution of plant processes there are only few studies on influence of spatially distributed irradiance due to lack of available data. Based on recent work on generating real irradiance maps with high spatial resolution this paper demonstrates their influence on solar field thermodynamics. For a case study an irradiance time series is chosen. One solar field section with several loops and collecting header is modeled for simulation purpose of parabolic trough collectors and oil as heat transfer medium. Assuming homogeneous mass flow distribution among all loops we observe spatially varying temperature characteristics. They are analysed without and with mass flow control and their impact on solar field control design is discussed. Finally, the potential of distributed irradiance data is outlined.

  8. Self-similarity in the chemical evolution of galaxies and the delay time distribution of SNe Ia

    CERN Document Server

    Walcher, C J; Minchev, I; Chiappini, C; Bergemann, M; Bruzual, G; Charlot, S; Coelho, P R T; Gallazzi, A; Martig, M

    2016-01-01

    Recent improvements in the age dating of stellar populations and single stars allow us to study the ages and abundance of stars and galaxies with unprecedented accuracy. We here compare the relation between age and \\alpha-element abundances for stars in the solar neighborhood to that of local, early-type galaxies. We find both relations to be very similar. Both fall into two regimes with a flat slope for ages younger than ~9 Gyr and a steeper slope for ages older than that value. This quantitative similarity seems surprising, given the different types of galaxies and scales involved. For the sample of early-type galaxies we also show that the data are inconsistent with literature delay time distributions of either single or double Gaussian shape. The data are consistent with a power law delay time distribution. We thus confirm that the delay time distribution inferred for the Milky Way from chemical evolution arguments also must apply to massive early-type galaxies. We also offer a tentative explanation for t...

  9. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    International Nuclear Information System (INIS)

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements

  10. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Koichi, E-mail: tanak@mmc.co.jp [Central Research Institute, Mitsubishi Materials Corporation, 1002-14 Mukohyama, Naka-shi, Ibaraki 311-0102 (Japan); Anders, André [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 53, Berkeley, California 94720 (United States)

    2015-11-15

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements.

  11. Two-size approximation: a simple way of treating the evolution of grain size distribution in galaxies

    CERN Document Server

    Hirashita, Hiroyuki

    2014-01-01

    Full calculations of the evolution of grain size distribution in galaxies are in general computationally heavy. In this paper, we propose a simple model of dust enrichment in a galaxy with a simplified treatment of grain size distribution by imposing a `two-size approximation'; that is, all the grain population is represented by small (grain radius a 0.03 micron) grains. We include in the model dust supply from stellar ejecta, destruction in supernova shocks, dust growth by accretion, grain growth by coagulation and grain disruption by shattering, considering how these processes work on the small and large grains. We show that this simple framework reproduces the main features found in full calculations of grain size distributions as follows. The dust enrichment starts with the supply of large grains from stars. At a metallicity level referred to as the critical metallicity of accretion, the abundance of the small grains formed by shattering becomes large enough to rapidly increase the grain abundance by acc...

  12. A methodology for determining the evolution law of gob permeability and its distributions in longwall coal mines

    Science.gov (United States)

    Zhang, Cun; Tu, Shihao; Zhang, Lei; Bai, Qingsheng; Yuan, Yong; Wang, Fangtian

    2016-04-01

    In order to understand the permeability evolution law of the gob by mining disturbances and obtain the permeability distribution of the fully compacted gob, comprehensive methods including theoretical analyses of monitoring data and numerical simulation are used to determine the permeability of gobs in the mining process. Based on current research, three zones of the vertical stress and permeability in the gob are introduced in this article, which are the caving rock mass accumulation zone, the gradually compacted zone and the fully compacted zone. A simple algorithm is written by using FISH language to be imported into the reservoir model. FISH language is an internal programming language in FLAC3D. It is possible to calculate the permeability at each zone with this algorithm in the mining process. Besides, we analyze the gas flow rates from seven gob gas ventholes (GGV) located on a longwall face operated in a mine of a Huainan coalfield in Huainan City, China. Combined with Darcy’s law, a calculation model of permeability around GGV in the gob is proposed. Using this model, the evolution law of permeability in the gob is deduced; the phases of permeability evolution are the decline stage and the stable stage. The result of the vertical stress monitoring data and good fitting effect of the permeability to the experimental data show that the permeability decline caused by the compaction of the gob is the principal reason for the decline stage. The stable stage indicates that the gob has been fully compacted, and the average period of full gob compaction is 47.75 d. The permeability in the middle of the compacted gob is much smaller than the permeability on the edge of the gob which presents an O shape trend. Besides, the little difference among the results of the numerical simulation, the permeability calculation model and other commonly used calculation models validate the correctness of the permeability calculation model and numerical simulation results.

  13. Evolution of Compatibility Range in the Rice-Magnaporthe oryzae System: An Uneven Distribution of R Genes Between Rice Subspecies.

    Science.gov (United States)

    Gallet, Romain; Fontaine, Colin; Bonnot, François; Milazzo, Joëlle; Tertois, Christophe; Adreit, Henri; Ravigné, Virginie; Fournier, Elisabeth; Tharreau, Didier

    2016-04-01

    Efficient strategies for limiting the impact of pathogens on crops require a good understanding of the factors underlying the evolution of compatibility range for the pathogens and host plants, i.e., the set of host genotypes that a particular pathogen genotype can infect and the set of pathogen genotypes that can infect a particular host genotype. Until now, little is known about the evolutionary and ecological factors driving compatibility ranges in systems implicating crop plants. We studied the evolution of host and pathogen compatibility ranges for rice blast disease, which is caused by the ascomycete Magnaporthe oryzae. We challenged 61 rice varieties from three rice subspecies with 31 strains of M. oryzae collected worldwide from all major known genetic groups. We determined the compatibility range of each plant variety and pathogen genotype and the severity of each plant-pathogen interaction. Compatibility ranges differed between rice subspecies, with the most resistant subspecies selecting for pathogens with broader compatibility ranges and the least resistant subspecies selecting for pathogens with narrower compatibility ranges. These results are consistent with a nested distribution of R genes between rice subspecies. PMID:26667186

  14. Spatial evolution of the electron energy distribution function in a low-pressure capacitively coupled plasma containing argon and krypton

    International Nuclear Information System (INIS)

    The spatial evolution of the electron energy distribution function (EEDF) in the axial direction of a capacitively coupled plasma with two parallel plate electrodes is investigated using an optical emission line-ratio method for Ar/Kr discharges. When the rf power is increased from 25 to 400 W at a pressure of 400 mTorr, we observe a transition from convex EEDFs to concave ones and a sharp increase in electron density, due to an α–γ mode transition, which is believed to be caused by the high-energy electrons originating in the high-voltage sheath. We also investigate the spatial evolution of the EEDF when the pressure is increased from 45 to 500 mTorr at a power of 100 W. The EEDF is uniform at pressures below 180 mTorr and becomes non-uniform at higher pressures, owing to the decrease in the energy relaxation length of the high-energy electrons. (paper)

  15. Evolution of grain size distribution in high-redshift dusty quasars: Integrating large amounts of dust and unusual extinction curves

    CERN Document Server

    Nozawa, Takaya; Hirashita, Hiroyuki; Takeuchi, Tsutomu T

    2014-01-01

    The discoveries of huge amounts of dust and unusual extinction curves in high-redshift quasars (z > 4) cast challenging issues on the origin and properties of dust in the early universe. In this Letter, we investigate the evolutions of dust content and extinction curve in a high-z quasar, based on the dust evolution model taking account of grain size distribution. First, we show that the Milky-Way extinction curve is reproduced by introducing a moderate fraction (~0.2) of dense molecular-cloud phases in the interstellar medium for a graphite-silicate dust model. Then we show that the peculier extinction curves in high-z quasars can be explained by taking a much higher molecular-cloud fraction (>0.5), which leads to more efficient grain growth and coagulation, and by assuming amorphous carbon instead of graphite. The large dust content in high-z quasar hosts is also found to be a natural consequence of the enhanced dust growth. These results indicate that grain growth and coagulation in molecular clouds are ke...

  16. Time-evolution of the ion velocity distribution function in the discharge of a Hall effect thruster

    CERN Document Server

    Mazouffre, S; Sadeghi, N

    2009-01-01

    The temporal characteristics of the Xe$^+$ ion axial Velocity Distribution Function (VDF) were recorded in the course of low-frequency discharge current oscillations ($\\sim$~14 kHz) of the 5 kW-class PPS$\\circledR$X000 Hall thruster. The evolution in time of the ion axial velocity component is monitored by means of a laser induced fluorescence diagnostic tool with a time resolution of 100 ns. As the number of fluorescence photons is very low during such a short time period, a hom-made pulse-counting lock-in system was used to perform real-time discrimination between background photons and fluorescence photons. The evolution in time of the ion VDF was observed at three locations along the thruster channel axis after a fast shut down of the thruster power. The anode discharge current is switched off at 2 kHz during 5 $\\mu$s without any synchronization with the current oscillation cycle. This approach allows to examine the temporal behavior of the ion VDF during decay and ignition of the discharge as well as dur...

  17. Near-Infrared Spectral Monitoring of Pluto's Ices: Spatial Distribution and Secular Evolution

    OpenAIRE

    Grundy, W. M.; Olkin, C. B.; Young, L. A.; Buie, M. W.; Young, E. F

    2013-01-01

    We report results from monitoring Pluto's 0.8 to 2.4 {\\mu}m reflectance spectrum with IRTF/SpeX on 65 nights over the dozen years from 2001 to 2012. The spectra show vibrational absorption features of simple molecules CH4, CO, and N2 condensed as ices on Pluto's surface. These absorptions are modulated by the planet's 6.39 day rotation period, enabling us to constrain the longitudinal distributions of the three ices. Absorptions of CO and N2 are concentrated on Pluto's anti-Charon hemisphere,...

  18. Evolution of fission-fragment mass distributions in the neutron-deficient lead region

    OpenAIRE

    Ghys, Lars; Andreyev, A.N.; Huyse, Mark; Van Duppen, Piet; Sels, Simon; Andel, B.; Antalic, S; Barzakh, A; Capponi, L.; Cocolios, Thomas Elias; Derkx, X.; De Witte, Hilde; J. Elseviers; Fedorov, D. V.; Fedosseev, V. N.

    2014-01-01

    Low-energy β-delayed fission of 194,196At and 200,202Fr was studied in detail at the mass separator ISOLDE at CERN. The fission-fragment mass distributions of daughter nuclei 194,196Po and 202Rn indicate a triple-humped structure, marking the transition between asymmetric fission of 178,180Hg and symmetric fission in the light Ra-Rn nuclei. Comparison with the macroscopic-microscopic finite-range liquid-drop model and the self-consistent approach employing the Gogny D1S energy den...

  19. Guangxi crustal structural evolution and the formation and distribution regularities of U-rich strata

    International Nuclear Information System (INIS)

    Based on summing up Guangxi geotectonic features and evolutionary regularities, this paper discusses the occurrence features, formation conditions and time-space distribution regularities of various U-rich strata during the development of geosyncline, platform and diwa stages, Especially, during diwa stage all those U-rich strata might be reworked to a certain degree and resulted in the mobilization of uranium, then enriching to form polygenetic composite uranium ore deposits with stratabound features. This study will be helpful for prospecting in the region

  20. Volcanic field elongation, vent distribution and tectonic evolution of continental rift: The Main Ethiopian Rift example

    Science.gov (United States)

    Mazzarini, Francesco; Le Corvec, Nicolas; Isola, Ilaria; Favalli, Massimiliano

    2015-04-01

    Magmatism and faulting operate in continental rifts and interact at a variety of scales, however their relationship is complex. The African rift, being the best example for both active continental rifting and magmatism, provides the ideal location to study the interplay between the two mechanisms. The Main Ethiopian Rift (MER), which connects the Afar depression in the north with the Turkana depression and Kenya Rift to the south, consists of two distinct systems of normal faults and its floor is scattered with volcanic fields formed by tens to several hundreds monogenetic, generally basaltic, small volcanoes and composite volcanoes and small calderas. The distribution of vents defines the overall shape of the volcanic field. Previous work has shown that the distribution of volcanic vents and the shape of a field are linked to its tectonic environment and its magmatic system. In order to distinguish the impact of each mechanism, we analyzed four volcanic fields located at the boundary between the central and northern MER, three of them (Debre Zeyit, Wonji and Kone) grew in the rift valley and one (Akaki) on the western rift shoulder. The elongation and shape of the fields were analyzed based on their vent distribution using the Principal Component Analysis (PCA), the Vent-to-Vent Distance (VVD), and the two dimensional symmetric Gaussian kernel density estimate methods. We extracted from these methods several parameters characterizing the spatial distribution of points (e.g., eccentricity (e), eigenvector index (evi), angular dispersion (Da)). These parameters allow to define at least three types of shape for volcanic fields: strong elongate (line and ellipse), bimodal/medium elongate (ellipse) and dispersed (circle) shapes. Applied to the natural example, these methods well differentiate each volcanic field. For example, the elongation of the field increases from shoulder to rift axis inversely to the angular dispersion. In addition, the results show that none of

  1. Effects of the scatter in sunspot group tilt angles on the large-scale magnetic field at the solar surface

    CERN Document Server

    Jiang, J; Schuessler, M

    2014-01-01

    The tilt angles of sunspot groups represent the poloidal field source in Babcock-Leighton-type models of the solar dynamo and are crucial for the build-up and reversals of the polar fields in Surface Flux Transport (SFT) simulations. The evolution of the polar field is a consequence of Hale's polarity rules, together with the tilt angle distribution which has a systematic component (Joy's law) and a random component (tilt-angle scatter). We determine the scatter using the observed tilt angle data and study the effects of this scatter on the evolution of the solar surface field using SFT simulations with flux input based upon the recorded sunspot groups. The tilt angle scatter is described in our simulations by a random component according to the observed distributions for different ranges of sunspot group size (total umbral area). By performing simulations with a number of different realizations of the scatter we study the effect of the tilt angle scatter on the global magnetic field, especially on the evolut...

  2. Analogous reserve distribution and tissue characteristics in quinoa and grass seeds suggest convergent evolution

    Science.gov (United States)

    Burrieza, Hernán P.; López-Fernández, María P.; Maldonado, Sara

    2014-01-01

    Quinoa seeds are highly nutritious due to the quality of their proteins and lipids and the wide range of minerals and vitamins they store. Three compartments can be distinguished within the mature seed: embryo, endosperm, and perisperm. The distribution of main storage reserves is clearly different in those areas: the embryo and endosperm store proteins, lipids, and minerals, and the perisperm stores starch. Tissues equivalent (but not homologous) to those found in grasses can be identified in quinoa, suggesting the effectiveness of this seed reserve distribution strategy; as in cells of grass starchy endosperm, the cells of the quinoa perisperm endoreduplicate, increase in size, synthesize starch, and die during development. In addition, both systems present an extra-embryonic tissue that stores proteins, lipids and minerals: in gramineae, the aleurone layer(s) of the endosperm; in quinoa, the micropylar endosperm; in both cases, the tissues are living. Moreover, the quinoa micropylar endosperm and the coleorhiza in grasses play similar roles, protecting the root in the quiescent seed and controlling dormancy during germination. This investigation is just the beginning of a broader and comparative study of the development of quinoa and grass seeds. Several questions arise from this study, such as: how are synthesis and activation of seed proteins and enzymes regulated during development and germination, what are the genes involved in these processes, and lastly, what is the genetic foundation justifying the analogy to grasses. PMID:25360139

  3. Antitropical distribution and evolution in the Indo-West Pacific Ocean

    Science.gov (United States)

    Briggs, J. C.

    1987-01-01

    Antitropical distributions of continental shelf, Indo-West Pacific species are probably not due to transgression of the tropics during the glacial periods, isothermic submergence, island integration, rising Neogene temperatures, or the Mesozoic dispersal of fragments from a Pacific continental mass. Characteristics of common antitropical patterns, plus information from systematic works on a variety on a variety of animal and plant groups, indicate that the long discarded "relict theory" of Theel (1885) appears to best fit the evidence, for it provides a mechanism whereby antitropical distribution may be brought about. The relict theory is compatible with the concept that the East Indies part of the Indo-West Pacific has been functioning as a center of evolutionary origin. It suggests that antitropical and associated disjunct patterns are produced as an older species, that has spread out to occupy a broad range, loses ground and gradually becomes supplanted by a younger species that had subsequently evolved in the East Indies. As this process goes on, the older species becomes restricted to a few isolated localities on the fringe of its original range. These isolates are often found to the north and south of the equatorial region but may include relict populations at the western edge of the Indian Ocean.

  4. Analogous reserve distribution and tissue characteristics in quinoa and grass seeds suggest convergent evolution.

    Science.gov (United States)

    Burrieza, Hernán P; López-Fernández, María P; Maldonado, Sara

    2014-01-01

    Quinoa seeds are highly nutritious due to the quality of their proteins and lipids and the wide range of minerals and vitamins they store. Three compartments can be distinguished within the mature seed: embryo, endosperm, and perisperm. The distribution of main storage reserves is clearly different in those areas: the embryo and endosperm store proteins, lipids, and minerals, and the perisperm stores starch. Tissues equivalent (but not homologous) to those found in grasses can be identified in quinoa, suggesting the effectiveness of this seed reserve distribution strategy; as in cells of grass starchy endosperm, the cells of the quinoa perisperm endoreduplicate, increase in size, synthesize starch, and die during development. In addition, both systems present an extra-embryonic tissue that stores proteins, lipids and minerals: in gramineae, the aleurone layer(s) of the endosperm; in quinoa, the micropylar endosperm; in both cases, the tissues are living. Moreover, the quinoa micropylar endosperm and the coleorhiza in grasses play similar roles, protecting the root in the quiescent seed and controlling dormancy during germination. This investigation is just the beginning of a broader and comparative study of the development of quinoa and grass seeds. Several questions arise from this study, such as: how are synthesis and activation of seed proteins and enzymes regulated during development and germination, what are the genes involved in these processes, and lastly, what is the genetic foundation justifying the analogy to grasses. PMID:25360139

  5. Analogous reserve distribution and tissue characteristics in quinoa and grass seeds suggest convergent evolution

    Directory of Open Access Journals (Sweden)

    Hernán Pablo Burrieza

    2014-10-01

    Full Text Available Quinoa seeds are highly nutritious due to the quality of their proteins and lipids and the wide range of minerals and vitamins they store. Three compartments can be distinguished within the mature seed: embryo, endosperm, and perisperm. The distribution of main storage reserves is clearly different in those areas: the embryo and endosperm store proteins, lipids, and minerals, and the perisperm stores starch. Tissues equivalent (but not homologous to those found in grasses can be identified in quinoa, suggesting the effectiveness of this seed reserve distribution strategy; as in cells of grass starchy endosperm, the cells of the quinoa perisperm endoreduplicate, increase in size, synthesize starch, and die during development. In addition, both systems present an extra-embryonic tissue that stores proteins, lipids and minerals: in gramineae, the aleurone layer(s of the endosperm; in quinoa, the micropylar endosperm; in both cases, the tissues are living. Moreover, the quinoa micropylar endosperm and the coleorhiza in grasses play similar roles, protecting the root in the quiescent seed and controlling dormancy during germination. This investigation is just the beginning of a broader and comparative study of the development of quinoa and grass seeds. Several questions arise from this study, such as: how are synthesis and activation of seed proteins and enzymes regulated during development and germination, what are the genes involved in these processes, and lastly, what is the genetic foundation justifying the analogy to grasses.

  6. Cosmological evolution of massive black holes: effects of Eddington ratio distribution and quasar lifetime

    CERN Document Server

    Cao, Xinwu

    2010-01-01

    A power-law time-dependent lightcurve for active galactic nuclei (AGNs) is expected by the self-regulated black hole growth scenario, in which the feedback of AGNs expels gas and shut down accretion. This is also supported by the observed power-law Eddington ratio distribution of AGNs. At high redshifts, the AGN life timescale is comparable with (or even shorter than) the age of the universe, which set a constraint on the minimal Eddington ratio for AGNs on the assumption of a power-law AGN lightcurve. The black hole mass function (BHMF) of AGN relics is calculated by integrating the continuity equation of massive black hole number density on the assumption of the growth of massive black holes being dominated by mass accretion with a power-law Eddington ratio distribution for AGNs. The derived BHMF of AGN relics at z=0 can fit the measured local mass function of the massive black holes in galaxies quite well, provided the radiative efficiency ~0.1 and a suitable power-law index for the Eddington ratio distrib...

  7. Evolution of a Quaternary paleoria (Southwest Amazonia) and its impact on the distribution of modern vegetation

    Science.gov (United States)

    Bertani, T. C.; Rossetti, D.; Hayakawa, E. H.

    2012-12-01

    years BP to 5,928 - 6,124 cal years BP. The deposits consist of sands and muds arranged into a fining upward. This is compatible with a fluvial channel evolution into a paralic depositional environment representing the final "ria" morphology observed in the remote sensing data. The δ13C, δ15N, and C/N suggest the dominance of freshwater phytoplankton mixed with C3 plants during most of the depositional time. However, around 6.000 cal years BP, there was an increase of C4 land plants. This was the onset of this vegetation type on the ria landform. Currently, this feature remains highlighted by grassland and shrubland, which are in sharp contrast with surrounding rainforest. Reconstructing the sedimentary history and the evolution of the associated vegetation over time is the key to discuss the origin of this fluvial ria, as well as its abandonment dynamics and impact on the establishment of modern vegetation types over this region.

  8. 3D-HST+CANDELS: The evolution of the galaxy size-mass distribution since z = 3

    Energy Technology Data Exchange (ETDEWEB)

    Van der Wel, A.; Rix, H.-W.; Chang, Yu-Yen [Max-Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Franx, M.; Fumagalli, M. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 AA Leiden (Netherlands); Van Dokkum, P. G.; Momcheva, I. G. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Skelton, R. E. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Whitaker, K. E. [Astrophysics Science Division, Goddard Space Center, Greenbelt, MD 20771 (United States); Brammer, G. B.; Ferguson, H. C.; Koekemoer, A. M.; Behroozi, P. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bell, E. F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Wuyts, S. [Max-Planck Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Holden, B. P.; Barro, G. [University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); McGrath, E. J. [Department of Physics and Astronomy, Colby College, Waterville, ME 0490 (United States); Häussler, B. [Physics Department, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Dekel, A., E-mail: vdwel@mpia.de [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); and others

    2014-06-10

    Spectroscopic+photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, we confirm that early-type galaxies are on average smaller than late-type galaxies at all redshifts, and we find a significantly different rate of average size evolution at fixed galaxy mass, with fast evolution for the early-type population, R {sub eff}∝(1 + z){sup –1.48}, and moderate evolution for the late-type population, R {sub eff}∝(1 + z){sup –0.75}. The large sample size and dynamic range in both galaxy mass and redshift, in combination with the high fidelity of our measurements due to the extensive use of spectroscopic data, not only fortify previous results but also enable us to probe beyond simple average galaxy size measurements. At all redshifts the slope of the size-mass relation is shallow, R{sub eff}∝M{sub ∗}{sup 0.22}, for late-type galaxies with stellar mass >3 × 10{sup 9} M {sub ☉}, and steep, R{sub eff}∝M{sub ∗}{sup 0.75}, for early-type galaxies with stellar mass >2 × 10{sup 10} M {sub ☉}. The intrinsic scatter is ≲0.2 dex for all galaxy types and redshifts. For late-type galaxies, the logarithmic size distribution is not symmetric but is skewed toward small sizes: at all redshifts and masses, a tail of small late-type galaxies exists that overlaps in size with the early-type galaxy population. The number density of massive (∼10{sup 11} M {sub ☉}), compact (R {sub eff} < 2 kpc) early-type galaxies increases from z = 3 to z = 1.5-2 and then strongly decreases at later cosmic times.

  9. Evolution of an operational hydrological model: from global to semi-distributed approach

    Science.gov (United States)

    Garavaglia, Federico; Le Lay, Matthieu; Gottardi, Frédéric; Garçon, Rémy

    2016-04-01

    MORDOR is a conceptual hydrological model extensively used in Électricité de France (EDF, French electric utility company) for operational applications: (i) hydrological forecasting, (ii) flood risk assessment, (iii) water balance and (iv) climate change studies. In its historical version, hereafter called MORDOR1996, this is a lumped, reservoir, elevation based model with hourly or daily areal rainfall and air temperature as the driving input data. The principal hydrological processes represented are evapotranspiration, direct and indirect runoff, ground water, snow and ice accumulation and melt, routing. The model has been intensively used at EDF for more than 25 years, in particular for modeling French mountainous watersheds. In order to consider the spatial heterogeneity of the input data (rainfall and air temperature) and the hydrological characteristics within a basin, the structure of model has been updated. The new version of the model, named MORDOR SD, is a semi-distributed hydrological model driven by elevation. The basin is spitted into several elevation bands on which a simple global MORDOR model is implemented; i.e. only evapotranspiration, direct and indirect runoff, snow and ice accumulation and melt are computed. However ground water and routing processes remain global. The primary purpose of this study is to present MORDOR SD model through a comparison with the historical version. The first result of this comparative study is that the new version provides better calibration-validation performances. Moreover the semi-distributed approach both allows to simplify the model structure (i.e. less degrees of freedom) and to reduce the equifinality problem in the calibration process. The model's parameters are calibrated at daily timestep with a genetic algorithm that uses a composed objective function. This complex function quantifies the good agreement between the simulated and observed runoff focusing on four different runoff samples: (i) time

  10. Perception of perspective angles

    NARCIS (Netherlands)

    Erkelens, C.J.

    2015-01-01

    We perceive perspective angles, that is, angles that have an orientation in depth, differently from what they are in physical space. Extreme examples are angles between rails of a railway line or between lane dividers of a long and straight road. In this study, subjects judged perspective angles bet

  11. Reconstruction of the thermal environment evolution from subsurface temperature distribution in large cities in East Asia

    Science.gov (United States)

    Hamamoto, H.; Goto, S.; Vuthy, M.; Nishijima, J.; Yamano, M.; Taniguchi, M.; Miyakoshi, A.; Hachinohe, S.; Sasaka, K.; Shiraishi, H.

    2009-12-01

    Temperature changes at the ground surface propagate into the underground and disturb the subsurface temperature structure. Analyzing disturbances in the subsurface temperature structure, we can reconstruct the past ground surface temperature (GST) change, which is closely related to the past surface air temperature change. This method can be applied to studies of thermal environment evolution in urban areas such as the development of “heat islands”. As part of an international multidisciplinary research project “Human Impacts on Urban Subsurface Environments”, we have been investigating GST histories in and around several large cities in East Asia, including Bangkok and Tokyo. We have also started a study on the subsurface thermal environment in Saitama prefecture, located on the north of Tokyo, as a research project of CESS (Center for Environmental Science in Saitama). The eastern part of Saitama prefecture is densely populated and considered to be a part of Tokyo Metropolitan area. In this presentation, we show the results of GST history reconstruction in the both areas. In Bangkok area, we conducted measurements of temperature profiles in groundwater monitoring wells at 45 sites in 2004, 2006, and 2008. In Saitama, we measured temperature profiles at 15 sites in 2009. We examined the shapes of the temperature profiles and selected ones that are not significantly disturbed by groundwater flow. Reconstruction of GST history for the last several hundred years was made at six sites in the Bangkok area and at two sites in the Saitama area. We used a multi-layer model that allows layers with different thermal properties, determining layer boundaries based on lithology of the formations around the wells. All of the reconstructed GST histories show surface warming in the last century. In the Bangkok area, the amount of the temperature increase ranges from 0.4 to 2.6 K and is larger in the city than in the area to the west of Bangkok and in the northern rural

  12. Probing the evolution of early-type galaxies using multi-colour number counts and redshift distributions

    CERN Document Server

    Nakata, F; Doi, M; Kashikawa, N; Kawasaki, W; Komiyama, Yu; Okamura, S; Sekiguchi, M; Yagi, M; Yasuda, N; Nakata, Fumiaki; Shimasaku, Kazuhiro; Doi, Mamoru; Kashikawa, Nobunari; Kawasaki, Wataru; Komiyama, Yutaka; Okamura, Sadanori; Sekiguchi, Maki; Yagi, Masafumi; Yasuda, Naoki

    1999-01-01

    We investigate pure luminosity evolution models for early-type (elliptical and S0) galaxies (i.e., no number density change or morphology transition), and examine whether these models are consistent with observed number counts in the B, I and K bands and redshift distributions of two samples of faint galaxies selected in the I and K bands. The models are characterized by the star formation time scale $\\tau_{SF}$ and the time $t_{gw}$ when galactic wind blows in addition to several other conventional parameters. We find the single-burst model ($\\tau_{SF}$=0.1 Gyr and $t_{gw}$=0.353 Gyr), which is known to reproduce the photometric properties of early-type galaxies in clusters, is inconsistent with redshift distributions of early-type galaxies in the field environment due to overpredictions of galaxies at $z\\gsim1.4$ even with strong extinction which is at work until $t_{gw}$. In order for dust extinction to be more effective, we change $\\tau_{SF}$ and $t_{gw}$ as free parameters, and find that models with $\\ta...

  13. Space-time evolution of meso-cenozoic extensional tectonics and distributions of uranium mineralizations in southeastern China

    International Nuclear Information System (INIS)

    With the theory of continental extensional tectonics, the distribution regularities of Meso-Cenozoic extensional tectonics of different types in southeastern China and their space-time evolution were discussed. then according to the known isotope age data of uranium mineralizations in the area, the relationship between the process of extensional tectonics and regional uranium metallogenesis, as well as the corresponding relations in space and time between extensional tectonics and uranium deposits of different types are analyzed. Based on the analysis above, the authors believe that the favourable tectonic environment created by the extensional tectonics is the fundamental reason that results in uranium metallogenesis. The pulse activities of the extensional tectonics and its subsequent magmatism determine the multi-stage processes of uranium mineralizations. The successive development of the extensional tectonics in different areas decides the temporal sequence and spatial distribution of uranium deposits of different types. The authors suggest that the uranium mineralizations of different types in southeastern China are characterized by an united ore-forming mechanism due to the apparent control of extensional tectonics to the regional uranium metallogenesis

  14. Multipoint observations of the spatial distribution and temporal evolution of the "Nose-like" structures in the inner magnetosphere

    Science.gov (United States)

    Luo, Hao; Du, Aimin; Ge, Yasong; Cao, Xin; Zhang, Ying; Huang, Sheng

    2016-04-01

    The "Nose-like" ion spectral structures are formed by ions in the near-Earth plasma sheet penetrating into the inner magnetosphere. Many studies had shown that the distribution of the Nose structures was controlled by the large-scale convection electric field, gradient-curvature drift and corotation electric field in the inner magnetosphere during geomagnetic quiet condition. However, during geomagnetic active periods, especially during the storms and substorms, the spatial and temporal characteristics and formation mechanism of different ions are still under debate. In this study, joint observations from Van Allen Probes, THEMIS, and Cluster will be used to statistically study the spatial distribution and temporal evolution of the "Nose-like" ion spectral structures in the inner magnetosphere. Backward tracing method based on Weimer 96 electric field and dipole magnetic field model was applied to simulate the ion structures and compared to the observations. The results show some important characteristics of the ion structures and will help us understand the injection mechanism of the ions from the plasma sheet into the inner magnetosphere and the relation between the storm and substorm, and thus provide important information for ring current formation.

  15. 3D Distribution of the Coronal Electron Density and its Evolution with Solar Cycle

    Science.gov (United States)

    Wang, Tongjiang; Reginald, Nelson Leslie; Davila, Joseph M.; St. Cyr, Orville Chris

    2016-05-01

    The variability of the solar white-light corona and its connection to the solar activity has been studied for more than a half century. It is widely accepted that the temporal variation of the total radiance of the K-corona follows the solar cycle pattern (e.g., correlated with sunspot number). However, the origin of this variation and its relationships with regard to coronal mass ejections and the solar wind are yet to be clearly understood. We know that the COR1-A and –B instruments onboard the STEREO spacecraft have continued to perform high-cadence (5 min) polarized brightness measurements from two different vantage points over a long period of time that encompasses the solar minimum of Solar Cycle 23 to the solar maximum of Solar Cycle 24. This extended period of polarized brightness measurements can now be used to reconstruct 3D electron density distributions of the corona between the heliocentric heights of 1.5-4.0 solar radii. In this study we have constructed the 3D coronal density models for 100 Carrington rotations (CRs) from 2007 to 2014 using the spherically symmetric inversion (SSI) method. The validity of these 3D density models is verified by comparing with similar 3D density models created by other means such as tomography, MHD modeling, and 2D density distributions inverted from the polarized brightness images from LASCO/C2 instrument onboard the SOHO spacecraft. When examining the causes for the temporal variation of the global electron content we find that its increase from the solar minimum to maximum depends on changes to both the total area and mean density of coronal streamers. We also find that the global and hemispheric electron contents show quasi-periodic variations with a period of 8-9 CRs during the ascending and maximum phases of Solar Cycle 24 through wavelet analysis. In addition, we also explore any obvious relationships between temporal variation of the global electron content with the photospheric magnetic flux, total mass of

  16. Study of dose distribution for stereotactic irradiation. Evolution of using gamma unit and linear accelerator

    International Nuclear Information System (INIS)

    Currently used stereotactic irradiation techniques that employ high-energy photon beams are based either on a gamma unit that uses stationary 201-cobalt beams or on isocentric linear accelerators. The techniques that rely on linear accelerators are divided into multiple non-coplanar converging arcs, precessional convergent irradiation, and others. These techniques have respective physical characteristics, for example, the precision of dose convergence and isodose distributions. We discuss the physical characteristics of the gamma unit, multiple non-coplanar converging arcs, and precessional convergent irradiation. In terms of the precision of dose convergence, the best was the gamma unit, followed by precessional convergent irradiation, with multiple non-coplanar converging arcs third. The precision of dose convergence deteriorated with diminishing field size in all techniques, and the precision of dose convergence was improved using a circular field with supplementary collimator among the techniques using linear accelerators. In addition, stereotactic irradiation techniques should be examined for disease treatment and running cost, because the techniques that have the greatest precision in dose convergence are incompatible with all-purpose usage. (author)

  17. Evolution of the Structure and Chromosomal Distribution of Histidine Biosynthetic Genes

    Science.gov (United States)

    Fani, Renato; Mori, Elena; Tamburini, Elena; Lazcano, Antonio

    1998-10-01

    A database of more than 100 histidine biosynthetic genes from different organisms belonging to the three primary domains has been analyzed, including those found in the now completely sequenced genomes of Haemophilus influenzae, Mycoplasma genitalium, Synechocystis sp., Methanococcus jannaschii, and Saccharomyces cerevisiae. The ubiquity of his genes suggests that it is a highly conserved pathway that was probably already present in the last common ancestor of all extant life. The chromosomal distribution of the his genes shows that the enterobacterial histidine operon structure is not the only possible organization, and that there is a diversity of gene arrays for the his pathway. Analysis of the available sequences shows that gene fusions (like those involved in the origin of the Escherichia coli and Salmonella typhimurium hisIE and hisB gene structures) are not universal. In contrast, the elongation event that led to the extant hisA gene from two homologous ancestral modules, as well as the subsequent paralogous duplication that originated hisF, appear to be irreversible and are conserved in all known organisms. The available evidence supports the hypothesis that histidine biosynthesis was assembled by a gene recruitment process.

  18. Evolution of bubble size distribution from gas blowout in shallow water

    Science.gov (United States)

    Zhao, Lin; Boufadel, Michel C.; Lee, Kenneth; King, Thomas; Loney, Norman; Geng, Xiaolong

    2016-03-01

    Gas is often emanated from the sea bed during a subsea oil and gas blowout. The size of a gas bubble changes due to gas dissolution in the ambient water and expansion as a result of a decrease in water pressure during the rise. It is important to understand the fate and transport of gas bubbles for the purpose of environmental and safety concerns. In this paper, we used the numerical model, VDROP-J to simulate gas formation in jet/plume upon release, and dissolution and expansion while bubble rising during a relatively shallow subsea gas blowout. The model predictions were an excellent match to the experimental data. Then a gas dissolution and expansion module was included in the VDROP-J model to predict the fate and transport of methane bubbles rising due to a blowout through a 0.10 m vertical orifice. The numerical results indicated that gas bubbles would increase the mixing energy in released jets, especially at small distances and large distances from the orifice. This means that models that predict the bubble size distribution (BSD) should account for this additional mixing energy. It was also found that only bubbles of certain sizes would reach the water surfaces; small bubbles dissolve fast in the water column, while the size of the large bubbles decreases. This resulted in a BSD that was bimodal near the orifice, and then became unimodal.

  19. Recurrent evolution of host-specialized races in a globally distributed parasite.

    Science.gov (United States)

    McCoy, Karen D; Chapuis, Elodie; Tirard, Claire; Boulinier, Thierry; Michalakis, Yannis; Bohec, Céline Le; Maho, Yvon Le; Gauthier-Clerc, Michel

    2005-11-22

    The outcome of coevolutionary interactions is predicted to vary across landscapes depending on local conditions and levels of gene flow, with some populations evolving more extreme specializations than others. Using a globally distributed parasite of colonial seabirds, the tick Ixodes uriae, we examined how host availability and geographic isolation influences this process. In particular, we sampled ticks from 30 populations of six different seabird host species, three in the Southern Hemisphere and three in the Northern Hemisphere. We show that parasite races have evolved independently on hosts of both hemispheres. Moreover, the degree of differentiation between tick races varied spatially within each region and suggests that the divergence of tick races is an ongoing process that has occurred multiple times across isolated areas. As I. uriae is vector to the bacterium responsible for Lyme disease Borrelia burgdorferi sensu lato, these results may have important consequence for the epidemiology of this disease. With the increased occurrence of novel interspecific interactions due to global change, these results also stress the importance of the combined effects of gene flow and selection for parasite diversification. PMID:16243689

  20. Near-Infrared Spectral Monitoring of Pluto's Ices: Spatial Distribution and Secular Evolution

    CERN Document Server

    Grundy, W M; Young, L A; Buie, M W; Young, E F

    2013-01-01

    We report results from monitoring Pluto's 0.8 to 2.4 {\\mu}m reflectance spectrum with IRTF/SpeX on 65 nights over the dozen years from 2001 to 2012. The spectra show vibrational absorption features of simple molecules CH4, CO, and N2 condensed as ices on Pluto's surface. These absorptions are modulated by the planet's 6.39 day rotation period, enabling us to constrain the longitudinal distributions of the three ices. Absorptions of CO and N2 are concentrated on Pluto's anti-Charon hemisphere, unlike absorptions of less volatile CH4 ice that are offset by roughly 90{\\deg} from the longitude of maximum CO and N2 absorption. In addition to the diurnal variations, the spectra show longer term trends. On decadal timescales, Pluto's stronger CH4 absorption bands have been getting deeper, while the amplitude of their diurnal variation is diminishing, consistent with additional CH4 absorption at high northern latitudes rotating into view as the sub-Earth latitude moves north (as defined by the system's angular moment...

  1. Distributed analysis with CRAB: The client-server architecture evolution and commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Codispoti, G.; /INFN, Bologna /Bologna U.; Cinquilli, M.; /INFN, Perugia; Fanfani, A.; /Bologna U.; Fanzago, F.; /CERN /INFN, CNAF; Farina, F.; /CERN /INFN, Milan Bicocca; Lacaprara, S.; /INFN, Legnaro; Miccio, V.; /CERN /INFN, CNAF; Spiga, D.; /CERN /INFN, Perugia /Perugia U.; Vaandering, E.; /Fermilab

    2008-01-01

    CRAB (CMS Remote Analysis Builder) is the tool used by CMS to enable running physics analysis in a transparent manner over data distributed across many sites. It abstracts out the interaction with the underlying batch farms, grid infrastructure and CMS workload management tools, such that it is easily usable by non-experts. CRAB can be used as a direct interface to the computing system or can delegate the user task to a server. Major efforts have been dedicated to the client-server system development, allowing the user to deal only with a simple and intuitive interface and to delegate all the work to a server. The server takes care of handling the users jobs during the whole lifetime of the users task. In particular, it takes care of the data and resources discovery, process tracking and output handling. It also provides services such as automatic resubmission in case of failures, notification to the user of the task status, and automatic blacklisting of sites showing evident problems beyond what is provided by existing grid infrastructure. The CRAB Server architecture and its deployment will be presented, as well as the current status and future development. In addition the experience in using the system for initial detector commissioning activities and data analysis will be summarized.

  2. Spatio-temporal evolution of the dust particle size distribution in dusty argon rf plasmas

    Science.gov (United States)

    Killer, Carsten; Mulsow, Matthias; Melzer, André

    2015-04-01

    An imaging Mie scattering technique has been developed to measure the spatially resolved size distribution of dust particles in extended dust clouds. For large dust clouds of micrometre-sized plastic particles confined in an radio frequency (rf) discharge, a segmentation of the dust cloud into populations of different sizes is observed, even though the size differences are very small. The dust size dispersion inside a population is much smaller than the difference between the populations. Furthermore, the dust size is found to be constantly decreasing over time while the particles are confined in an inert argon plasma. The processes responsible for the shrinking of the dust in the plasma have been addressed by mass spectrometry, ex situ microscopy of the dust size, dust resonance measurements, in situ determination of the dust surface temperature and Fourier transform infrared absorption (FT-IR). It is concluded that both a reduction of dust size and its mass density due to outgassing of water and other volatile constituents as well as chemical etching by oxygen impurities are responsible for the observations.

  3. Reconstruction of the thermal environment evolution from subsurface temperature distribution in Japan and Thailand

    Science.gov (United States)

    Hamamoto, H.; Yamano, M.; Goto, S.; Hachinohe, S.; Shiraishi, H.; Ishiyama, T.; Miyakoshi, A.; Taniguchi, M.; Arimoto, H.; Kitaoka, K.

    2012-12-01

    Temperature changes at the ground surface propagate into the underground and disturb the subsurface temperature structure. Analyzing disturbances in the subsurface temperature structure, we can reconstruct the past ground surface temperature (GST) change, which is closely related to the past surface air temperature change. This method can be applied to studies of thermal environment evolution in urban areas such as the development of "heat islands". We have been investigating GST histories in three areas, which are located in Japan and Thailand. The three areas are the northern part of Kanto area, Osaka area, and Bangkok area. Kanto area and Osaka area have the greatest and second greatest population in Japan, each other. Bangkok area has the greatest population in Thailand. In the northern part of Kanto area, we conducted measurements of temperature profiles in groundwater monitoring wells at 25 sites in 2009, 2010, and 2011. In Osaka area, temperature profiles were measured at 31 sites in 2011 as the project of the Sumitomo Foundation (M. Taniguchi). In Bangkok area, we measured temperature profiles at 45 sites in 2004, 2006, 2008, and 2010. We examined the shapes of the temperature profiles and selected ones that are not significantly disturbed by groundwater flow. Reconstruction of GST history for the last about 300 hundred years was made at two sites in the northern part of Kanto area, at six sites in Osaka area, and at six sites in Bangkok area. We used a multi-layer model that allows layers with different thermal properties, determining layer boundaries based on lithology of the formations around the wells. All of the reconstructed GST histories show surface warming in the last century. In the northern part of Kanto area, the amount of the temperature increase from 1700 to 2010 is about 2.5 K at both sites. In Osaka area, the amount of the temperature increase from 1700 to 2010 ranges from 2.5 K to 5.0 K and is larger in the city center and the southern part

  4. Interaction of low energy protons, deuterons, H{sub 2}{sup +} and D{sub 2}{sup +} with carbon foils: energy-angle distributions and velocity dependence of the energy loss

    Energy Technology Data Exchange (ETDEWEB)

    Cantero, E.D. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 S.C. Bariloche (Argentina); Consejo Nacional de Investigaciones Cientificas y Technicas (Argentina); Lantschner, G.H.; Arista, N.R. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 S.C. Bariloche (Argentina)

    2011-12-15

    We have performed measurements of energy-angle distributions for low energy (E < 10 keV) hydrogen ions transmitted through thin amorphous carbon foils. The applicability of standard potentials for the description of the multiple scattering is tested by making comparisons of the experimental results with theoretical calculations using the model of Sigmund and Winterbon on a broad angular scale. The angular dependence of the energy loss for protons and deuterons is analyzed using the three-components model of Fama et al., that separately considers the contribution of elastic and inelastic mechanisms and the roughness effect. Additionally, the velocity dependence of the stopping power and the possible existence of isotopic and molecular effects in the energy loss is investigated by measurements with H{sup +}, D{sup +}, H{sub 2}{sup +} and D{sub 2}{sup +} beams of velocities between 0.15 and 0.6 a.u. Among other things the results show first that the angular distributions can be very well described with the multiple scattering formalism of Sigmund and Winterbon, secondly that the multiple scattering process follows the energy-angle scaling law: E*{Theta} equals constant, and thirdly that no isotopic effect (H{sup +} vs D{sup +}) is observed in the stopping cross-sections measured in the forward direction, which corresponds to inelastic energy loss

  5. The distribution of Extremely High Accretion Rates and Metallicities of QSO's as a Function of Redshift over Cosmic Evolution

    Science.gov (United States)

    Abu Seif, Nasser; Kazanas, Demosthenes

    2016-07-01

    The investigation of how QSOs' extremity of accretion rates vary with redshift has remained a major focus of our study in the last five years. How does the evolution of QSOs trace the accretion history of early SMBH? What does accretion at super-Eddington rates look like? Does the correlation between SMBHs and metallicity of QSOs emission line evolve differently at high redshift? Is it a surprise that metallicity is high at high redshift, or is this expected? Here, we establish a new database for the width of an emission line (e.g., Hβ, Mg II and C IV) to obtain a large statistical sample of QSOs at different redshifts. We calculated L/LEdd that determined mass from previous studies (Sloan Digital Sky Survey (SDSS)). We investigated the significant evolution of L/ LEdd for any value of MBH as a function of redshift. Also, we investigated the evolution and distribution of the accretion rate (L/LEdd) over cosmic time with a concentration on the extremely high accretion rate sources at high redshift. The current study investigated the accretion rate (L/LEdd) correlation to other QSO properties and investigated how the accretion of Black Holes L/LEdd and MBH occurs within heavily obscured environments. Our research found that some QSOs are radiating near the Eddington limit with L/ Ledd ~ 1 and those QSOs have extreme accretion. We also found that the lowest M BH has the highest accretion rate, a result that was already noted by McClure & Dunlop (2004). The distribution of Eddington ratio displayed by QSOs clearly shows that all luminous QSOs accreted at their Eddington limit have a poor approximation. This result is important because it is often assumed that optically luminous QSOs are accreting at their Eddington limit within the models of QSOs evolution. We determined the peak of the L/LEdd versus redshift and we found the largest of those peaks to be at the interval of redshift (1law photon-indexes with both SMBH mass (MBH) and the accretion rates. We found that

  6. Morphological number-count and redshift distributions to I < 26 from the Hubble Deep Field Implications for the evolution of Ellipticals, Spirals and Irregulars

    CERN Document Server

    Driver, S P; Couch, W J; Odewahn, S C; Windhorst, R A; Phillipps, S; Lanzetta, K; Yahil, A

    1998-01-01

    We combine the photometric redshift data of Fernandez-Soto et al. (1997) with the morphological data of Odewahn et al. (1996) for all galaxies with I 24. (2) Spiral galaxies are present in numbers consistent with zero- evolution predictions to I = 22. Beyond this magnitude some net- positive evolution is required. Although the number-counts are consistent with the passive-evolution predictions to I=26.0 the redshift distributions favor number AND luminosity evolution. (3) There is no obvious explanation for the late-type/irregular class and this category requires further subdivision. While a small fraction of the population lies at low redshift (i.e. true irregulars), the majority lie at redshifts, 1 1.5 mergers are frequent and, taken in conjunction with the absence of normal spirals at z > 2, the logical inference is that they represent the progenitors of normal spirals forming via hierarchical merging.

  7. The New Method Judged Horizontal Distribution Pattern by Uniform Angle Index%角尺度判断林木水平分布格局的新方法

    Institute of Scientific and Technical Information of China (English)

    赵中华; 惠刚盈; 胡艳波; 张弓乔

    2016-01-01

    正态分布检验林分(树种)平均角尺度判断林木水平分布格局方法对2个林分/种群的判断结果与 Ripley’s L函数点格局分析方法判断结果完全一致,而聚集指数 R与 Ripley’s L检验的判断结果的差别明显增加,说明置信水平对水平分布格局判断结果影响比较明显。【结论】研究提出的正态分布检验林分(树种)平均角尺度判断林木水平分布格局的方法克服了统一的置信区间不适用于评判抽样调查或群落中数量较少的种群水平分布格局问题,进一步完善了角尺度判断林木水平分布格局理论,提升了角尺度判断林木水平分布格局的准确性与适用范围。%Objective]This paper proposed a new method to judge tree horizontal distribution pattern by uniform angle index in order to further improve the theory of the uniform angle index to judge tree horizontal distribution pattern.[Method]6 000 simulated stands with an area of 70 m × 70 m and with different densities and distribution patterns were produced by stand spatial structure analysis software ( Winkelmass) ,the 2 field-tested broad-leaved korean pine forests in northeast China were then used to verify the accuracy of the new method for judging the stand and population horizontal distribution pattern,and the results were also compared with R aggregation index and Ripley’s L.[Result]According to the conclusion of the mean value of uniform angle index ( W ) of random distribution stand conform to the normal distribution and its relationships with the standard deviation,this contribution proposed the new method of judgment stand/population spatial horizontal distribution pattern by uniform angle index. The 6 000 simulated stands with different density and horizontal distribution patterns were produced by Winkelmass with an area of 70 m × 70 m. The results of simulation data showed that the coincidence rate of uniform angle index normal distribution test method was 100% to different density

  8. Distribution of melt along the East Pacific Rise from 9°30' to 10°N from an amplitude variation with angle of incidence (AVA) technique

    Science.gov (United States)

    Marjanović, Milena; Carton, Hélène; Carbotte, Suzanne M.; Nedimović, Mladen R.; Mutter, John C.; Canales, J. Pablo

    2015-10-01

    We examine along-axis variations in melt content of the axial magma lens (AML) beneath the fast-spreading East Pacific Rise (EPR) using an amplitude variation with angle of incidence (AVA) crossplotting method applied to multichannel seismic data acquired in 2008. The AVA crossplotting method, which has been developed for and, so far, applied for hydrocarbon prospection in sediments, is for the first time applied to a hardrock environment. We focus our analysis on 2-D data collected along the EPR axis from 9°29.8'N to 9°58.4'N, a region which encompasses the sites of two well-documented submarine volcanic eruptions (1991-1992 and 2005-2006). AVA crossplotting is performed for a ˜53 km length of the EPR spanning nine individual AML segments (ranging in length from ˜3.2 to 8.5 km) previously identified from the geometry of the AML and disruptions in continuity. Our detailed analyses conducted at 62.5 m interval show that within most of the analysed segments melt content varies at spatial scales much smaller (a few hundred of metres) than the length of the fine-scale AML segments, suggesting high heterogeneity in melt concentration. At the time of our survey, about 2 yr after the eruption, our results indicate that the three AML segments that directly underlie the 2005-2006 lava flow are on average mostly molten. However, detailed analysis at finer-scale intervals for these three segments reveals AML pockets (from >62.5 to 812.5 m long) with a low melt fraction. The longest such mushy section is centred beneath the main eruption site at ˜9°50.4'N, possibly reflecting a region of primary melt drainage during the 2005-2006 event. The complex geometry of fluid flow pathways within the crust above the AML and the different response times of fluid flow and venting to eruption and magma reservoir replenishment may contribute to the poor spatial correlation between incidence of hydrothermal vents and presence of highly molten AML. The presented results are an important

  9. Energy and pitch-angle dispersions of LLBL/cusp ions seen at middle altitudes: predictions by the open magnetosphere model

    OpenAIRE

    Lockwood, M.

    1997-01-01

    Numerical simulations are presented of the ion distribution functions seen by middle-altitude spacecraft in the low-latitude boundary layer (LLBL) and cusp regions when reconnection is, or has recently been, taking place at the equatorial magnetopause. From the evolution of the distribution function with time elapsed since the field line was opened, both the observed energy/observation-time and pitch-angle/energy dispersions are well reproduced. Distribution functions showing a mixture of mag...

  10. Nuclear Matter Distributions in {sup 6}He and {sup 8}He from Small Angle {ital p}-He Scattering in Inverse Kinematics at Intermediate Energy

    Energy Technology Data Exchange (ETDEWEB)

    Alkhazov, G.; Andronenko, M.; Dobrovolsky, A.; Gavrilov, G.; Khanzadeev, A.; Korolev, G.; Lobodenko, A.; Seliverstov, D.; Timofeev, N.; Vorobyov, A.; Yatsoura, V. [Petersburg Nuclear Physics Institute (PNPI), 188350 Gatchina (Russia); Egelhof, P.; Geissel, H.; Irnich, H.; Muenzenberg, G.; Nickel, F.; Schwab, W.; Suzuki, T. [Gesellschaft fuer Schwerionenforschung (GSI), 64291 Darmstadt (Germany); Mutterer, M.; Neumaier, S.; Theobald, J. [Institut fuer Kernphysik (IKP), TH-Darmstadt, 64289 Darmstadt (Germany)

    1997-03-01

    Differential cross sections for {ital p}-{sup 6}He and {ital p}-{sup 8}He elastic scattering have been measured in inverse kinematics at small momentum transfers up to {vert_bar}t{vert_bar}=0.05(GeV/ c){sup 2} and projectile energies of about 700MeV/nucleon. Nuclear matter densities deduced from the data are consistent with the concept that {sup 6}He and {sup 8}He nuclei have an {alpha}-like core and a significant neutron skin. The rms radii of the nuclear matter distributions were determined to be R{sub m} ({sup 6}He)=2.30{plus_minus}0.07fm and R{sub m} ({sup 8}He)=2.45{plus_minus}0.07fm. {copyright} {ital 1997} {ital The American Physical Society}

  11. Nuclear matter distributions in {sup 6}He and {sup 8}He from small angle pHe scattering in inverse kinematics at intermediate energy

    Energy Technology Data Exchange (ETDEWEB)

    Alkhazov, G.D. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Andronenko, M.N. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Dobrovolsky, A.V. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Egelhof, P. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Gavrilov, G.E. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Geissel, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Irnich, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Khanzadeev, A.V. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Korolev, G.A. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Lobodenko, A.A. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Muenzenberg, G. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Mutterer, M. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Neumaier, S.R. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Nickel, F. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Schwab, W. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Seliverstov, D.M. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Suzuki, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Theobald, J.P. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Timofeev, N.A. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Vorobyov, A.A. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation); Yatsoura, V.I. [St. Petersburg Inst. of Nuclear Physics, Gatchina (Russian Federation)

    1996-11-01

    Differential cross sections for p{sup 6}He and p{sup 8}He elastic scattering have been measured in inverse kinematics at small momentum transfers up to vertical stroke t vertical stroke =0.05 (GeV/c){sup 2} and projectile energies of about 700 MeV/u. Nuclear matter densities deduced from the data are consistent with the concept that {sup 6}He and {sup 8}He nuclei have an {alpha}-like core and a significant neutron skin. The r.m.s. radii of the nuclear matter distributions were determined to be R{sub m}({sup 6}He)=2.30{+-}0.07 fm and R{sub m}({sup 8}He)=2.45{+-}0.07 fm. (orig.)

  12. On gamma_5 in higher-order QCD calculations and the NNLO evolution of the polarized valence distribution

    CERN Document Server

    Moch, S; Vogt, A

    2015-01-01

    We discuss the prescription for the Dirac matrix gamma_5 in dimensional regularization used in most second- and third-order QCD calculations of collider cross sections. We provide an alternative implementation of this approach that avoids the use of an explicit form of gamma_5 and of its (anti-) commutation relations in the most important case of no more than one gamma_5 in each fermion trace. This treatment is checked by computing the third-order corrections to the structure functions F_2 and g_1 in charged-current deep-inelastic scattering with axial-vector couplings to the W-bosons. We derive the so far unknown third-order helicity-difference splitting function Delta P_ns^(2)s that contributes to the next-to-next-to-leading order (NNLO) evolution of the polarized valence quark distribution of the nucleon. This function is negligible at momentum fractions x >~ 0.3 but relevant at x << 1.

  13. Stratigraphical discontinuities, tropical landscape evolution and soil distribution relationships in a case study in SE-Brazil

    Directory of Open Access Journals (Sweden)

    M. Cooper

    2002-09-01

    Full Text Available On a regional summit surface in the county of Piracicaba (SP within the Peripheric Depression of São Paulo, formed of discontinued flattened tops, there is an abrupt transition between a Typic Hapludox and a Kandiudalfic Eutrudox, together with two stoneline layers. Using stratigraphical, mineralogical, and cartographic studies, this transition and the soil distribution of this surface were studied, correlating them with the different parent materials and the morphoclimatic model of landscape evolution in Southeastern Brazil. The Typic Hapludox was formed on a sandy Cenozoic deposit (Q that overlies a pellitic deposit of the Iratí formation (Pi, representing a regional erosive discordance. Westwards to the Piracicaba River, this sequence is interrupted by a diabase sill overlain by a red clayey material which gave origin to the Kandiudalfic Eutrudox. Two post-Permian depositional events were identified by the two stonelines and stratigraphical discontinuities. The first event generated the deposition of a sandy sediment in the form of levelled alveoluses on regional barriers, most of these formed by dikes and diabase sills, probably during a drier phase. The second depositional event, leading to the deposition of the red clay was probably the dissection of the previously formed pediplane during a humid climate, followed by another pedimentation process during a later, drier period.

  14. Non-axisymmetric structure in the satellite dwarf galaxy NGC 2976: Implications for its dark/bright mass distribution and evolution

    International Nuclear Information System (INIS)

    We present the result of an extensive search for non-axisymmetric structures in the dwarf satellite galaxy of M81, NGC 2976, using multiwavelength archival observations. The galaxy is known to present kinematic evidence for a bisymmetric distortion; however, the stellar bar presence is controversial. This controversy motivated the possible interpretation of NGC 2976 as presenting an elliptical disk triggered by a prolate dark matter halo. We applied diagnostics used in spiral galaxies in order to detect stellar bars or spiral arms. The m = 2 Fourier phase has a jump around 60 arcsec, consistent with a central bar and bisymmetric arms. The CO, 3.6 μm surface brightness, and the dust lanes are consistent with a gas-rich central bar and possibly with gaseous spiral arms. The bar-like feature is offset close to 20° from the disk position angle, in agreement with kinematic estimations. The kinematic jumps related to the dust lanes suggest that the bar perturbation in the disk kinematics is non-negligible and the reported non-circular motions, the central gas excess, and the nuclear X-ray source (active galactic nucleus/starburst) might be produced by the central bar. Smoothed particle hydrodynamics simulations of disks inside triaxial dark halos suggest that the two symmetric spots at 130 arcsec and the narrow arms may be produced by gas at turning points in an elliptical disk, or, alternatively, the potential ellipticity can be produced by a tidally induced strong stellar bar/arms; in both cases the rotation curve interpretation is, importantly, biased. The M81 group is a natural candidate to trigger the bisymmetric distortion and the related evolution as suggested by the H I tidal bridge detected by Chynoweth et al. We conclude that both mechanisms, the gas-rich bar and spiral arms triggered by the environment (tidal stirring) and primordial halo triaxiality, can explain most of the NGC 2976 non-circular motions, mass redistribution, and nuclear activity

  15. Non-axisymmetric structure in the satellite dwarf galaxy NGC 2976: Implications for its dark/bright mass distribution and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, Octavio; Hernandez-Toledo, Hector; Cano, Mariana; Pichardo, Bárbara [Instituto de Astronomía, Universidad Nacional Autonóma de Mexico, A.P. 70-264, 04510 México, D.F. (Mexico); Puerari, Ivanio [Instituto Nacional de Astrofísica Optica y Electrónica, Calle Luis Enrique Erro 1, 72840 Sta. Maria Tonantzintla, Puebla (Mexico); Buta, Ronald [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Groess, Robert, E-mail: octavio@astro.unam.mx [School of Computational and Applied Mathematics, University of Witwatersrand, Private Bag 3, WITS 2050 (South Africa)

    2014-02-01

    We present the result of an extensive search for non-axisymmetric structures in the dwarf satellite galaxy of M81, NGC 2976, using multiwavelength archival observations. The galaxy is known to present kinematic evidence for a bisymmetric distortion; however, the stellar bar presence is controversial. This controversy motivated the possible interpretation of NGC 2976 as presenting an elliptical disk triggered by a prolate dark matter halo. We applied diagnostics used in spiral galaxies in order to detect stellar bars or spiral arms. The m = 2 Fourier phase has a jump around 60 arcsec, consistent with a central bar and bisymmetric arms. The CO, 3.6 μm surface brightness, and the dust lanes are consistent with a gas-rich central bar and possibly with gaseous spiral arms. The bar-like feature is offset close to 20° from the disk position angle, in agreement with kinematic estimations. The kinematic jumps related to the dust lanes suggest that the bar perturbation in the disk kinematics is non-negligible and the reported non-circular motions, the central gas excess, and the nuclear X-ray source (active galactic nucleus/starburst) might be produced by the central bar. Smoothed particle hydrodynamics simulations of disks inside triaxial dark halos suggest that the two symmetric spots at 130 arcsec and the narrow arms may be produced by gas at turning points in an elliptical disk, or, alternatively, the potential ellipticity can be produced by a tidally induced strong stellar bar/arms; in both cases the rotation curve interpretation is, importantly, biased. The M81 group is a natural candidate to trigger the bisymmetric distortion and the related evolution as suggested by the H I tidal bridge detected by Chynoweth et al. We conclude that both mechanisms, the gas-rich bar and spiral arms triggered by the environment (tidal stirring) and primordial halo triaxiality, can explain most of the NGC 2976 non-circular motions, mass redistribution, and nuclear activity

  16. The use of small-angle scattering and the maximum-entropy method for shape-model determination from distance-distribution functions

    International Nuclear Information System (INIS)

    The maximum-entropy method is well established for the analysis of scattering data [Bricogne (1993)[. For this method, prior structure knowledge can be included in the structure determination. This prior estimate is an essential element for a successful application of the maximum-entropy method. The most likely prior estimate can be found by maximization of the entropy. With the assumption a priori of a special type of structure model, the unknown parameters can be calculated from real-space functions. For practical use, analytical expressions for the Fourier transform of model scattering curves, the distance-distribution function of the models, are of interest. Formulas are presented for rotational ellipsoids, Gaussian chains and two-phase spheres, and a parameter estimation by the program MAXENT is demonstrated for the ellipsoidal shape of cytochrome c using theoretical X-ray scattering curves calculated from atomic coordinates. The calculated dimensions of prolate and oblate ellipsoids agree within the error limits with the direct structure-related inertia-equivalent ellipsoid of the molecule. Furthermore, error limits have been determined from the a posteriori probability or 'evidence' function for the model parameters. To avoid over-interpretation of the scattering data, the real number of degrees of freedom is calculated for noisy data. This measure of information content is almost independent of the collimation distortion but strongly influenced by the statistical noise in the scattering data. The numerical value is smaller than the ideal number of degrees of freedom provided by the information theory. (orig.)

  17. The use of small-angle scattering and the maximum-entropy method for shape-model determination from distance-distribution functions

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.J. [Max-Delbrueck-Centrum fuer Molekulare Medizin Berlin-Buch SdoeR, Berlin (Germany); Hansen, S. [Royal Veterinary and Agricultural Univ., Copenhagen (Denmark). Dept. of Mathematics and Physics; Puerschel, H.-V. [Max-Delbrueck-Centrum fuer Molekulare Medizin Berlin-Buch SdoeR, Berlin (Germany)

    1996-10-01

    The maximum-entropy method is well established for the analysis of scattering data [Bricogne (1993)]. For this method, prior structure knowledge can be included in the structure determination. This prior estimate is an essential element for a successful application of the maximum-entropy method. The most likely prior estimate can be found by maximization of the entropy. With the assumption a priori of a special type of structure model, the unknown parameters can be calculated from real-space functions. For practical use, analytical expressions for the Fourier transform of model scattering curves, the distance-distribution function of the models, are of interest. Formulas are presented for rotational ellipsoids, Gaussian chains and two-phase spheres, and a parameter estimation by the program MAXENT is demonstrated for the ellipsoidal shape of cytochrome c using theoretical X-ray scattering curves calculated from atomic coordinates. The calculated dimensions of prolate and oblate ellipsoids agree within the error limits with the direct structure-related inertia-equivalent ellipsoid of the molecule. Furthermore, error limits have been determined from the a posteriori probability or `evidence` function for the model parameters. To avoid over-interpretation of the scattering data, the real number of degrees of freedom is calculated for noisy data. This measure of information content is almost independent of the collimation distortion but strongly influenced by the statistical noise in the scattering data. The numerical value is smaller than the ideal number of degrees of freedom provided by the information theory. (orig.).

  18. Airborne measurements of the spatial distribution of aerosol chemical composition across Europe and evolution of the organic fraction

    Directory of Open Access Journals (Sweden)

    W. T. Morgan

    2009-12-01

    Full Text Available The spatial distribution of aerosol chemical composition and the evolution of the Organic Aerosol (OA fraction is investigated based upon airborne measurements of aerosol chemical composition in the planetary boundary layer across Europe. Sub-micron aerosol chemical composition was measured using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS. A range of sampling conditions were evaluated, including relatively clean background conditions, polluted conditions in North-Western Europe and the near-field to far-field outflow from such conditions. Ammonium nitrate and OA were found to be the dominant chemical components of the sub-micron aerosol burden, with mass fractions ranging from 20–50% each. Ammonium nitrate was found to dominate in North-Western Europe during episodes of high pollution, reflecting the enhanced NOx and ammonia sources in this region. OA was ubiquitous across Europe and concentrations generally exceeded sulphate by 50–100%. A factor analysis of the OA burden was performed in order to probe the evolution across this large range of spatial and temporal scales. Two separate Oxygenated Organic Aerosol (OOA components were identified; one representing an aged-OOA, termed Low Volatility-OOA and another representing fresher-OOA, termed Semi Volatile-OOA on the basis of their mass spectral similarity to previous studies. The factors derived from different flights were not chemically the same but rather reflect the range of OA composition sampled during a particular flight. Significant chemical processing of the OA was observed downwind of major sources in North-Western Europe, with the LV-OOA component becoming increasingly dominant as the distance from source and photochemical processing increased. The measurements suggest that the aging of OA can be viewed as a continuum, with a progression from a less oxidised, semi-volatile component to a highly oxidised, less-volatile component. Substantial amounts of

  19. First measurement of the double-inclusive B/Bbar hadron energy distribution in e+e- annihilations, and of angle-dependent moments of the B and Bbar energies

    International Nuclear Information System (INIS)

    The authors have made the first measurement of the double-inclusive B/(bar B) energy distribution in e+e- annihilations, using a sample of 400,000 hadronic Z0-decay events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B/(bar B)-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used to calculate the B energies in this novel technique. They measured the B/(bar B) energies with good efficiency and resolution over the full kinematic range. They measured moments of the scaled energies of the B and (bar B) hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions they tested the ansatz of factorization in heavy-quark production. A recent next-to-leading order calculation reproduces the data

  20. First measurement of the double-inclusive B/Bbar hadron energy distribution in e+e- annihilations, and of angle-dependent moments of the B and Bbar energies

    CERN Document Server

    Abe, K

    2004-01-01

    We have made the first measurement of the double-inclusive B/Bbar energy distribution in e+e- annihilations, using a sample of 400,000 hadronic Z0 decay events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B/Bbar decay vertices with high efficiency and purity, and to provide measurements of the kinematic quantities used to calculate the B energies in this novel technique. We measured the B/Bbar energies with good efficiency and resolution over the full kinematic range. We measured moments of the scaled energies of the B and Bbar hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions we tested the ansatz of factorisation in heavy-quark production. A recent next-to-leading order calculation reproduces the data.

  1. First measurement of the double-inclusive B/B hadron energy distribution in e+e- annihilations, and of angle-dependent moments of the B and B

    International Nuclear Information System (INIS)

    We have made the first measurement of the double-inclusive B/B energy distribution in e+e- annihilations, using a sample of 400,000 hadronic Z0-decay events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B/B-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used to calculate the B energies in this novel technique. We measured the B/B energies with good efficiency and resolution over the full kinematic range. We measured moments of the scaled energies of the B and B hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions we tested the ansatz of factorisation in heavy-quark production. A recent next-to-leading order calculation reproduces the data. (orig.)

  2. Flat-topped mountain ranges: Their global distribution and value for understanding the evolution of mountain topography

    Science.gov (United States)

    Calvet, Marc; Gunnell, Yanni; Farines, Bernard

    2015-07-01

    Extensive tracts of low-gradient topography in steep mountain ranges, either forming rangetop plateaus or terraced pediments on range flanks, are widely distributed in mountain belts around the world. Before the advent of plate tectonics, such populations of planar landforms were interpreted as vestiges of a post-orogenic raised peneplain, i.e., a low-gradient land surface resulting from the decay, during long intervals of base-level stability, of a previous mountain range that was subsequently raised once again to great elevations-thus forming a new mountain range. This two-stage model has been challenged by theories that advocate continuity in tectonic processes and more gradual changes in base level, and thus expect a more immediate and proportionate response of geomorphic systems. Here we present a global survey of erosion surfaces in mountain ranges and put existing theories and empirical evidence into a broad perspective calling for further research into the rates and regimes of long-term mountain evolution. The resulting library of case studies provides opportunities for comparative analysis and helps to classify the landform mosaics that are likely to arise from the interplay between (i) crustal regimes, which at convergent plate margins need be neither uniform nor steady at all times; (ii) radiation-driven and gravity-driven geomorphic regimes, which are mainly determined by crustal boundary conditions and climate; and (iii) paleogeography, through which clues about base-level changes can be obtained. We examine intracratonic and plate-margin settings, with examples from thin-skinned fold belts, thick-skinned fold belts, island-arc and other subduction-related settings, and bivergent collisional orogens. Results reveal that the existence of erosion surfaces is not a simple function of geodynamic setting. Although some erosion surfaces are pre-orogenic, evidence about their predominantly post-orogenic age is supported by apatite fission-track and helium

  3. 角钢输电塔杆件风压及体型系数的风洞试验研究%Wind tunnel tests for wind load distribution and shape coefficient of angle-made-transmission towers

    Institute of Scientific and Technical Information of China (English)

    楼文娟; 王东; 沈国辉; 金晓华

    2013-01-01

    以220 kV角钢输电塔为研究对象,设计制作了1:2.5的大比例刚性节段模型,在均匀湍流场中进行同步测压风洞试验,获得了输电塔主材、斜材和辅材杆件的风压分布规律和体型系数沿杆件展长的分布.归纳了风荷载对塔身各杆件的作用特点以及体型系数随风向角的变化规律.对于角钢杆件,当角钢内角迎风时,阻力系数与升力系数均较大,杆件处于双向受力状态.对整塔段的体型系数进行了试验值和国内外规范取值的对比.结果表明:按我国规范取值偏小,试验值与国外规范取值接近.%An angle-made-transmission tower with 220 kV was researched. A 1: 2.5 large scale rigid section model was fabricated and the wind tunnel measuring pressure test was performed in homogeneous turbulence flow. The wind pressure distribution and shape coefficient along main members, oblique members and auxiliary members were obtained. The characteristic of wind load functioning on each member was induced, and the law of varying shape coefficient of each member s sections along with wind angle was summarized. It shows part of the angle steels which have both large drag and lift coefficients are under the action of double-direction distributed wind load in some specific wind directions. The standard value was compared with the tested value of the section model s shape coefficient. The result shows that the domestic standard value is smaller than the tested value which tends to be unsafe to structure design, while the foreign standard value well agrees with the tested value.

  4. Time evolution of the phonon and ionized impurity limited 2D hot carrier distribution function in a n-GaAs square quantum well (QW)

    Science.gov (United States)

    Zandler, G.; Vass, E.

    1988-10-01

    The time evolution of the distribution function of hot electrons interacting with ionized impurities, acoustic and polar optical phonons is studied in terms of the Boltzmann integral equation. The calculated distribution functions are used to determine the charge carrier drift velocity, the average energy as well as the average momentum and energy loss rates as a function of time at constant values of the lattice temperature and charge carrier density. The stationary non-equilibrium values of these quantities are found to be established after 3-4 ps.

  5. Size Effects in Angle-Resolved Photoelectron Spectroscopy of Free Rare-Gas Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Rolles, D.; Zhang, H.; Pesic, Z.D.; Bilodeau, R.C.; Wills, A.; Kukk, E.; Rude, B.S.; Ackerman, G.D.; Bozek, J.D.; Muino, R.D.; de Abajo, F.J.G.; Berrah, N.; /Western

    2007-05-23

    The photoionization of free Xe clusters is investigated by angle-resolved time-of-flight photoelectron spectroscopy. The measurements probe the evolution of the photoelectron angular distribution parameter as a function of photon energy and cluster size. While the overall photon-energy-dependent behavior of the photoelectrons from the clusters is very similar to that of the free atoms, distinct differences in the angular distribution point at cluster-size-dependent effects. Multiple scattering calculations trace their origin to elastic photoelectron scattering.

  6. Soft gluons away from jets: distribution and correlation

    International Nuclear Information System (INIS)

    Recently, an exact conformal mapping between soft gluons emitted from jets at large angle in e+e--annihilation and those in the BFKL evolution of a high energy hadron has been proposed. We elucidate some remarkable aspects of this correspondence and use them to analytically compute the distribution and correlation of gluons in the interjet region. We also establish the timelike counterpart of Mueller's dipole model and discuss the resulting linear and nonlinear evolution equations.

  7. Reading Angles in Maps

    Science.gov (United States)

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  8. Insecticidal genes of Yersinia spp.: taxonomical distribution, contribution to toxicity towards Manduca sexta and Galleria mellonella, and evolution

    Directory of Open Access Journals (Sweden)

    Schachtner Joachim

    2008-12-01

    Full Text Available Abstract Background Toxin complex (Tc proteins termed TcaABC, TcdAB, and TccABC with insecticidal activity are present in a variety of bacteria including the yersiniae. Results The tc gene sequences of thirteen Yersinia strains were compared, revealing a high degree of gene order conservation, but also remarkable differences with respect to pseudogenes, sequence variability and gene duplications. Outside the tc pathogenicity island (tc-PAIYe of Y. enterocolitica strain W22703, a pseudogene (tccC2'/3' encoding proteins with homology to TccC and similarity to tyrosine phosphatases at its C-terminus was identified. PCR analysis revealed the presence of the tc-PAIYe and of tccC2'/3'-homologues in all biotype 2–5 strains tested, and their absence in most representatives of biotypes 1A and 1B. Phylogenetic analysis of 39 TccC sequences indicates the presence of the tc-PAIYe in an ancestor of Yersinia. Oral uptake experiments with Manduca sexta revealed a higher larvae lethality of Yersinia strains harbouring the tc-PAIYe in comparison to strains lacking this island. Following subcutaneous infection of Galleria mellonella larvae with five non-human pathogenic Yersinia spp. and four Y. enterocolitica strains, we observed a remarkable variability of their insecticidal activity ranging from 20% (Y. kristensenii to 90% (Y. enterocolitica strain 2594 dead larvae after five days. Strain W22703 and its tcaA deletion mutant did not exhibit a significantly different toxicity towards G. mellonella. These data confirm a role of TcaA upon oral uptake only, and suggest the presence of further insecticidal determinants in Yersinia strains formerly unknown to kill insects. Conclusion This study investigated the tc gene distribution among yersiniae and the phylogenetic relationship between TccC proteins, thus contributing novel aspects to the current discussion about the evolution of insecticidal toxins in the genus Yersinia. The toxic potential of several Yersinia

  9. Optimal reconstruction angles

    International Nuclear Information System (INIS)

    The question of optimal projection angles has recently become of interest in the field of reconstruction from projections. Here, studies are concentrated on the n x n pixel space, where literative algorithms such as ART and direct matrix techniques due to Katz are considered. The best angles are determined in a Gauss--Markov statistical sense as well as with respect to a function-theoretical error bound. The possibility of making photon intensity a function of angle is also examined. Finally, the best angles to use in an ART-like algorithm are studied. A certain set of unequally spaced angles was found to be preferred in several contexts. 15 figures, 6 tables

  10. 冕洞内矢量磁场的分布和演化%Distribution and Evolution of Vector Magnetic Fields in Coronal Holes

    Institute of Scientific and Technical Information of China (English)

    杨书红

    2012-01-01

    With the observations from the SOHO, Hinode, STEREO, and SDO, we investigate some aspects of CHs in detail for the first time, such as the evolution of vector magnetic field and magnetic nonpotentiality in CHs, and obtain a series of results. (1) Response of the solar atmosphere to the magnetic field distribution and evolution in a CH. We study the magnetic fields in a CH and at the CH boundary, and present the corresponding atmospheric response of different overlying layers to the magnetic field distribution and evolution. We also quantitatively analyze the relationship between the magnetic flux density and atmospheric emissions at different wavelengths. (2) Evolution of dipoles in an equatorial CH and its effect on the decay of the CH. We investigate the evolution of dipolar magnetic fields in an equatorial CH region. In the CH, the submergence of initial loops after their emergence is observed for the first time. The area where the dipoles are located becomes a place of mixed polarities instead of the unipolar fields, resulting in the change of the overlying corona from a CH area to a quiet region. (3) Distribution of vector magnetic fields and magnetic nonpotentiality of CHs. We investigate the vector magnetic fields, current densities, and current helicities in two CHs, and compare them with two quiet regions. We find that: (i) in the areas where the large current helicities are concentrated, there are strong vertical and horizontal field elements; (ii) the mean current density in the magnetic flux concentrations with the vertical fields stronger than 100 Gs is as large as (0.012 0.001) Am-2, consistent with that in the flare productive active regions; (iii) the magnetic fields in both the CHs and the quiet regions are nonpotential. (4) SDO observations of magnetic reconnection at CH boundaries. At the CH boundaries, we find many coronal jets as the signatures of magnetic reconnection, below which the magnetic emergence and cancellation are observed. We study

  11. Photoelectric angle converter

    Science.gov (United States)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  12. The evolution and distribution of life in the Precambrian eon-Global perspective and the Indian record

    Indian Academy of Sciences (India)

    M Sharma; Y Shukla

    2009-11-01

    The discovery of Precambrian microfossils in 1954 opened a new vista of investigations in the field of evolution of life. Although the Precambrian encompasses 87% of the earth’s history, the pace of organismal evolution was quite slow. The life forms as categorised today in the three principal domains viz. the Bacteria, the Archaea and the Eucarya evolved during this period. In this paper, we review the advancements made in the Precambrian palaeontology and its contribution in understanding the evolution of life forms on earth. These studies have enriched the data base on the Precambrian life. Most of the direct evidence includes fossil prokaryotes, protists, advanced algal fossils, acritarchs, and the indirect evidence is represented by the stromatolites, trace fossils and geochemical fossils signatures. The Precambrian fossils are preserved in the form of compressions, impressions, and permineralized and biomineralized remains.

  13. The Evolution of the M_BH-sigma relation Inferred from the Age Distribution of Local Early-Type Galaxies and AGN Evolution

    CERN Document Server

    Shankar, Francesco; Haiman, Zoltan

    2008-01-01

    We utilize the local velocity dispersion function (VDF) of spheroids, together with their inferred age--distributions, to predict the VDF at higher redshifts (01.3 excluded at the 99% confidence level. A direct match between the characteristic BH mass in the VDF--based and quasar LF--based BH mass functions also yields a mean Eddington ratio of lambda ~ 0.5-1 that is roughly constant within 00.23 for alpha>1.5. abridged

  14. EFFECT OF ENVIRONMENT ON GALAXIES' MASS-SIZE DISTRIBUTION: UNVEILING THE TRANSITION FROM OUTSIDE-IN TO INSIDE-OUT EVOLUTION

    International Nuclear Information System (INIS)

    The distribution of galaxies on the mass-size plane as a function of redshift or environment is a powerful test for galaxy formation models. Here we use integral-field stellar kinematics to interpret the variation of the mass-size distribution in two galaxy samples spanning extreme environmental densities. The samples are both identically and nearly mass-selected (stellar mass M * ≳ 6 × 109 M ☉) and volume-limited. The first consists of nearby field galaxies from the ATLAS3D parent sample. The second consists of galaxies in the Coma Cluster (Abell 1656), one of the densest environments for which good, resolved spectroscopy can be obtained. The mass-size distribution in the dense environment differs from the field one in two ways: (1) spiral galaxies are replaced by bulge-dominated disk-like fast-rotator early-type galaxies (ETGs), which follow the same mass-size relation and have the same mass distribution as in the field sample; (2) the slow-rotator ETGs are segregated in mass from the fast rotators, with their size increasing proportionally to their mass. A transition between the two processes appears around the stellar mass M crit ≈ 2 × 1011 M ☉. We interpret this as evidence for bulge growth (outside-in evolution) and bulge-related environmental quenching dominating at low masses, with little influence from merging. In contrast, significant dry mergers (inside-out evolution) and halo-related quenching drives the mass and size growth at the high-mass end. The existence of these two processes naturally explains the diverse size evolution of galaxies of different masses and the separability of mass and environmental quenching

  15. EFFECT OF ENVIRONMENT ON GALAXIES' MASS-SIZE DISTRIBUTION: UNVEILING THE TRANSITION FROM OUTSIDE-IN TO INSIDE-OUT EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Cappellari, Michele [Sub-Department of Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)

    2013-11-20

    The distribution of galaxies on the mass-size plane as a function of redshift or environment is a powerful test for galaxy formation models. Here we use integral-field stellar kinematics to interpret the variation of the mass-size distribution in two galaxy samples spanning extreme environmental densities. The samples are both identically and nearly mass-selected (stellar mass M {sub *} ≳ 6 × 10{sup 9} M {sub ☉}) and volume-limited. The first consists of nearby field galaxies from the ATLAS{sup 3D} parent sample. The second consists of galaxies in the Coma Cluster (Abell 1656), one of the densest environments for which good, resolved spectroscopy can be obtained. The mass-size distribution in the dense environment differs from the field one in two ways: (1) spiral galaxies are replaced by bulge-dominated disk-like fast-rotator early-type galaxies (ETGs), which follow the same mass-size relation and have the same mass distribution as in the field sample; (2) the slow-rotator ETGs are segregated in mass from the fast rotators, with their size increasing proportionally to their mass. A transition between the two processes appears around the stellar mass M {sub crit} ≈ 2 × 10{sup 11} M {sub ☉}. We interpret this as evidence for bulge growth (outside-in evolution) and bulge-related environmental quenching dominating at low masses, with little influence from merging. In contrast, significant dry mergers (inside-out evolution) and halo-related quenching drives the mass and size growth at the high-mass end. The existence of these two processes naturally explains the diverse size evolution of galaxies of different masses and the separability of mass and environmental quenching.

  16. Fission Fragment Folding Angle Distributions for the Systems 11B+237Np, 12C+236U, and 16O+232Th in the Energy Range 1.1B<2.1

    International Nuclear Information System (INIS)

    Fission fragment folding angle distributions have been measured for the systems 11B+237Np, 12C+236U, and 16O+232Th, populating the same compound nucleus (248Cf) and at similar excitation energies (Ex 45-100 MeV). The full momentum transfer and incomplete momentum transfer fusion-fission components have been separated over the bombarding energy range 1.1c.m/VB 2.1. It is observed that the largest value of the ratio of the transfer fission to the total fission is around 10 to 15% at the highest energy investigated. Over the energy range mentioned above, it is found that the transfer fission corrected fission fragment anisotropies are not significantly different from the values already obtained from the analysis of the total fission data reported earlier and hence the conclusions reached from the inclusive data remain unchanged. The anisotropy data were analyzed for the two cases corresponding to fission events with sizable fission barriers (Bf>T) and with smaller fission barriers (Bf>T). It was interesting to find that the effective moment of inertia (Jeff) values deduced from the latter component were consistent with the values from Sierk prescription used in the former case

  17. Nucleation and crystal growth in a suspension of charged colloidal silica spheres with bi-modal size distribution studied by time-resolved ultra-small-angle X-ray scattering.

    Science.gov (United States)

    Hornfeck, Wolfgang; Menke, Dirk; Forthaus, Martin; Subatzus, Sebastian; Franke, Markus; Schöpe, Hans-Joachim; Palberg, Thomas; Perlich, Jan; Herlach, Dieter

    2014-12-01

    A suspension of charged colloidal silica spheres exhibiting a bi-modal size distribution of particles, thereby mimicking a binary mixture, was studied using time-resolved ultra-small-angle synchrotron X-ray scattering (USAXS). The sample, consisting of particles of diameters d(A) = (104.7 ± 9.0) nm and d(B) = (88.1 ± 7.8) nm (d(A)/d(B) ≈ 1.2), and with an estimated composition A(0.6(1))B(0.4(1)), was studied with respect to its phase behaviour in dependance of particle number density and interaction, of which the latter was modulated by varying amounts of added base (NaOH). Moreover, its short-range order in the fluid state and its eventual solidification into a long-range ordered colloidal crystal were observed in situ, allowing the measurement of the associated kinetics of nucleation and crystal growth. Key parameters of the nucleation kinetics such as crystallinity, crystallite number density, and nucleation rate density were extracted from the time-resolved scattering curves. By this means an estimate on the interfacial energy for the interface between the icosahedral short-range ordered fluid and a body-centered cubic colloidal crystal was obtained, comparable to previously determined values for single-component colloidal systems. PMID:25481168

  18. First measurement of the double-inclusive B/Bbar hadron energy distribution in e+e- annihilations, and of angle-dependent moments of the B and Bbar energies

    CERN Document Server

    Burrows, P N

    2004-01-01

    The have made the first measurement of the double-inclusive B/(bar B) energy distribution in e sup + e sup - annihilations, using a sample of 400,000 hadronic Z sup 0 -decay events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct B/(bar B)-decay vertices with high efficiency and purity, and to provide precise measurements of the kinematic quantities used to calculate the B energies in this novel technique. They measured the B/(bar B) energies with good efficiency and resolution over the full kinematic range. They measured moments of the scaled energies of the B and (bar B) hadrons vs. the opening angle between them. By comparing these results with perturbative QCD predictions they tested the ansatz of factorization in heavy-quark production. A recent next-to-leading order calculation reproduces the data.

  19. Phase angle measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Madge, R.; Fischer, D.

    1996-01-01

    Real-time measure of the power transfer across a transmission line was discussed. Phase angle measurement techniques, algorithms and applications relevant to power utilities were assessed. Phase-based applications compute the voltage angle difference between two stations, thereby allowing for power transfer calculations and power system control applications. A list of phase angle measurement applications was provided. It includes frequency measurement, state estimation, adaptive relaying, power system control, system restoration, real power flow monitoring and stability assessment, reactive power requirements monitoring, HVDC modulation, subsynchronous resonance, sequence of event recording, and loss reduction and fault location. The optimum timing requirement was determined for each application. Among the timing systems available today, the Global Positioning System (GPS), supported by powerful computers and other custom hardware, is the only tool that can provide the accuracy and coverage needed by today`s power system applications. Commercially available equipment for phase angle measurements was also reviewed. 30 refs., 32 tabs., 5 figs.

  20. Does Angling Technique Selectively Target Fishes Based on Their Behavioural Type?

    Directory of Open Access Journals (Sweden)

    Alexander D M Wilson

    Full Text Available Recently, there has been growing recognition that fish harvesting practices can have important impacts on the phenotypic distributions and diversity of natural populations through a phenomenon known as fisheries-induced evolution. Here we experimentally show that two common recreational angling techniques (active crank baits versus passive soft plastics differentially target wild largemouth bass (Micropterus salmoides and rock bass (Ambloplites rupestris based on variation in their behavioural tendencies. Fish were first angled in the wild using both techniques and then brought back to the laboratory and tested for individual-level differences in common estimates of personality (refuge emergence, flight-initiation-distance, latency-to-recapture and with a net, and general activity in an in-lake experimental arena. We found that different angling techniques appear to selectively target these species based on their boldness (as characterized by refuge emergence, a standard measure of boldness in fishes but not other assays of personality. We also observed that body size was independently a significant predictor of personality in both species, though this varied between traits and species. Our results suggest a context-dependency for vulnerability to capture relative to behaviour in these fish species. Ascertaining the selective pressures angling practices exert on natural populations is an important area of fisheries research with significant implications for ecology, evolution, and resource management.

  1. An investigation of processes controlling the evolution of the boundary layer aerosol size distribution properties at the Swedish background station Aspvreten

    Directory of Open Access Journals (Sweden)

    P. Tunved

    2004-01-01

    Full Text Available Aerosol size distributions have been measured at the Swedish background station Aspvreten (58.8° N, 17.4° E. Different states of the aerosol were determined using a novel application of cluster analysis. The analysis resulted in eight different clusters capturing different stages of the aerosol lifecycle. The atmospheric aerosol size distributions were interpreted as belonging to fresh, intermediate and aged types of size distribution. With aid of back trajectory analysis we present statistics concerning the relation of source area and different meteorological parameters using a non-Lagrangian approach. Source area is argued to be important although not sufficient to describe the observed aerosol properties. Especially processing by clouds and precipitation is shown to be crucial for the evolution of the aerosol size distribution. As much as 60% of the observed size distributions present features that are likely to be related to cloud processes or wet deposition. The lifetime properties of different sized aerosols are discussed by means of measured variability of the aerosol size distribution. Processing by clouds and precipitation is shown to be especially crucial in the size range 100 nm and larger. This indicates an approximate limit for activation in clouds to 100 nm in this type of environment. The aerosol lifecycle is discussed. Size distributions indicating signs of recent new particle formation (~30% of the observed size distributions represent the first stage in the lifecycle. Aging of the aerosol size distribution may follow two branches: either growth by condensation and coagulation or processing by non-precipitating clouds. In both cases mass is accumulated. Wet removal is the main process capable of removing aerosol mass. Wet deposition is argued to be an important mechanism in reaching a state where nucleation may occur (i.e. sufficiently low aerosol surface area in environments similar to the one studied.

  2. Quantifying the Luminosity Evolution in Gamma-ray Bursts

    CERN Document Server

    Kocevski, D; Kocevski, Daniel; Liang, Edison

    2006-01-01

    We estimate the luminosity evolution and formation rate for over 900 GRBs by using redshift and luminosity data calculated by Band, Norris, $&$ Bonnell (2004) via the lag-luminosity correlation. By applying maximum likelihood techniques, we are able to infer the true distribution of the parent GRB population's luminosity function and density distributions in a way that accounts for detector selection effects. We find that after accounting for data truncation, there still exists a significant correlation between the average luminosity and redshift, indicating that distant GRBs are on average more luminous than nearby counterparts. This is consistent with previous studies showing strong source evolution and also recent observations of under luminous nearby GRBs. We find no evidence for beaming angle evolution in the current sample of GRBs with known redshift, suggesting that this increase in luminosity can not be due to an evolution of the collimation of gamma-ray emission. The resulting luminosity function...

  3. CrystalMoM: a tool for modeling the evolution of Crystals Size Distributions in magmas with the Method of Moments

    Science.gov (United States)

    Colucci, Simone; de'Michieli Vitturi, Mattia; Landi, Patrizia

    2016-04-01

    It is well known that nucleation and growth of crystals play a fundamental role in controlling magma ascent dynamics and eruptive behavior. Size- and shape-distribution of crystal populations can affect mixture viscosity, causing, potentially, transitions between effusive and explosive eruptions. Furthermore, volcanic samples are usually characterized in terms of Crystal Size Distribution (CSD), which provide a valuable insight into the physical processes that led to the observed distributions. For example, a large average size can be representative of a slow magma ascent, and a bimodal CSD may indicate two events of nucleation, determined by two degassing events within the conduit. The Method of Moments (MoM), well established in the field of chemical engineering, represents a mesoscopic modeling approach that rigorously tracks the polydispersity by considering the evolution in time and space of integral parameters characterizing the distribution, the moments, by solving their transport differential-integral equations. One important advantage of this approach is that the moments of the distribution correspond to quantities that have meaningful physical interpretations and are directly measurable in natural eruptive products, as well as in experimental samples. For example, when the CSD is defined by the number of particles of size D per unit volume of the magmatic mixture, the zeroth moment gives the total number of crystals, the third moment gives the crystal volume fraction in the magmatic mixture and ratios between successive moments provide different ways to evaluate average crystal length. Tracking these quantities, instead of volume fraction only, will allow using, for example, more accurate viscosity models in numerical code for magma ascent. Here we adopted, for the first time, a quadrature based method of moments to track the temporal evolution of CSD in a magmatic mixture and we verified and calibrated the model again experimental data. We also show how

  4. Evolution of The Proton Velocity Distribution due to Stochastic Heating in the Near-Sun Solar Wind

    CERN Document Server

    Klein, Kristopher G

    2016-01-01

    We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfv\\'en-wave turbulence under the assumption that $\\beta$ is small. We apply our analysis to protons undergoing stochastic heating in the supersonic fast solar wind and obtain proton distributions at heliocentric distances ranging from 4 to 30 solar radii. We find that the proton distribution develops non-Gaussian structure with a flat core and steep tail. For $r >5 \\ R_{\\rm S}$, the proton distribution is well approximated by a modified Moyal distribution. Comparisons with future measurements from \\emph{Solar Probe Plus} could be used to test whether stochastic heating is occurring in the solar-wind acceleration region.

  5. The stages of evolution of the partially molten rock material with a heterogeneous distribution of the solid phase

    Science.gov (United States)

    Karakin, A. V.; Pokatashkin, P. A.

    2016-03-01

    The paper addresses the interpretation of the geochemical laboratory experiments aimed at studying the differentiation of partially molten rocks in the terrestrial planets. These experiments simulate the early stages of material differentiation when the layers with the different chemical and petrological composition are formed in the planets. Density inversion which may arise at a certain stage of this process leads to the emergence of the Rayleigh-Taylor instability. The lifetime of this instability is estimated, and the different phases of its evolution are explored. It is shown that the laboratory experiments do not always adequately reproduce the nature of the physical processes which occur in the interior of the planets. The suggested methods are also used for interpreting the evolution of intrusions during their differentiation. The obtained results can be helpful in analyzing the intrusions for minerals.

  6. Small angle X-ray scattering from hydrating tricalcium silicate

    International Nuclear Information System (INIS)

    The small-angle X-ray scattering technique was used to study the structural evolution of hydrated tricalcium silicate at room temperature. The changes in specific area of the associated porosity and the evolution of density fluctuations in the solid hydrated phase were deduced from the scattering data. A correlation of these variations with the hydration mechanism is tried. (Author)

  7. The evolution of early-type galaxies in clusters from z~ 0.8 to z~ 0: the ellipticity distribution and the morphological mix

    CERN Document Server

    Vulcani, Benedetta; Dressler, Alan; Fasano, Giovanni; Valentinuzzi, Tiziano; Couch, Warrick; Moretti, Alessia; Simard, Luc; Desai, Vandana; Bettoni, Daniela; D'Onofrio, Mauro; Cava, Antonio; Varela, Jesús

    2010-01-01

    We present the ellipticity distribution and its evolution for early-type galaxies in clusters from z~0.8 to z~0, based on the WIde-field Nearby Galaxy-cluster Survey (WINGS) (0.04M_B+1.208z>-21. Analyzing this sample, we do not recover exactly the same results of the mass-limited sample. Hence the selection criteria are crucial to characterize the galaxy properties: the choice of the magnitude-de limited sample implies the loss of many less massive galaxies and so it biases the final conclusions. Moreover, although we are adopting the same selection criteria, our results in the magnitude-delimited sample are also not in agreement with those of Holden et al.(2009). This is due to the fact that our and their low-z samples have a different magnitude distribution because the Holden et al.(2009) sample suffers from incompleteness at faint magnitudes.

  8. The rotation period distributions of 4--10 Myr T Tauri stars in Orion OB1: New constraints on pre-main-sequence angular momentum evolution

    CERN Document Server

    Karim, Md Tanveer; Briceno, Cesar; Vivas, A Katherina; Raetz, Stefanie; Mateu, Cecilia; Downes, Juan Jose; Calvet, Nuria; Hernandez, Jesus; Neuhauser, Ralph; Mugrauer, Markus; Takahashi, Hidenori; Tachihara, Kengo; Chini, Rolf; Cruz-Dias, Gustavo A; Aarnio, Alicia; James, David J; Hackstein, Moritz

    2016-01-01

    Most existing studies of the angular momentum evolution of young stellar populations have focused on the youngest (1-3 Myr) T Tauri stars. In contrast, the angular momentum distributions of older T Tauri stars (4-10 Myr) have been less studied, even though they hold key insight to understanding stellar angular momentum evolution at a time when protoplanetary disks have largely dissipated and when models therefore predict changes in the rotational evolution that can in principle be tested. We present a study of photometric variability among 1,974 confirmed T Tauri members of various sub-regions of the Orion OB1 association, and with ages spanning 4-10 Myr, using optical time-series from three different surveys. For 564 of the stars (~32% of the weak-lined T Tauri stars and ~13% of the classical T Tauri stars in our sample) we detect statistically significant periodic variations which we attribute to the stellar rotation periods, making this one of the largest samples of T Tauri star rotation periods yet publis...

  9. Schumpeter's Evolution

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    This draft of a book on Schumpeter is distributed for commenting. It is a stylised intellectual biography that focus on the emergence and extension of the Schumpeterian vision and analysis of economic and social evolution. The draft provides novel interpretations of Schumpeter's six major books. He...... reworking of his basic theory of economic evolution in Development from 1934, and this reworking was continued in Cycles from 1939. Here Schumpeter also tried to handle the statistical and historical evidence on the waveform evolution of the capitalist economy. Capitalism from 1942 modified the model of...... economic evolution and added evolutionary contributions to other social sciences. History, which was published by his widow, was based on his evolutionary theory of the history of economic analysis. This sequential analysis of Schumpeter's six books demonstrates the progress he within his research...

  10. The quadriceps angle

    DEFF Research Database (Denmark)

    Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona;

    2012-01-01

    : Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...

  11. Yaw Angle Demonstration

    Science.gov (United States)

    1994-01-01

    The Large Angle Magnetic Suspension Test Fixture (LAMSTF) is a 5 degree-of -freedom repulsive force magnetic suspension system designed to study the control of objects over large magnetic gaps. A digital control algorithm uses 6 sets of laser-sheet sensors and 5 control coils to position a cylinder 3' above the plane of electromagnetics

  12. The lateral angle revisited

    DEFF Research Database (Denmark)

    Morgan, Jeannie; Lynnerup, Niels; Hoppa, R.D.

    2013-01-01

    measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability. The...

  13. Distribution, evolution, and diversity of retrotransposons at the flamenco locus reflect the regulatory properties of piRNA clusters.

    Science.gov (United States)

    Zanni, Vanessa; Eymery, Angéline; Coiffet, Michael; Zytnicki, Matthias; Luyten, Isabelle; Quesneville, Hadi; Vaury, Chantal; Jensen, Silke

    2013-12-01

    Most of our understanding of Drosophila heterochromatin structure and evolution has come from the annotation of heterochromatin from the isogenic y; cn bw sp strain. However, almost nothing is known about the heterochromatin's structural dynamics and evolution. Here, we focus on a 180-kb heterochromatic locus producing Piwi-interacting RNAs (piRNA cluster), the flamenco (flam) locus, known to be responsible for the control of at least three transposable elements (TEs). We report its detailed structure in three different Drosophila lines chosen according to their capacity to repress or not to repress the expression of two retrotransposons named ZAM and Idefix, and we show that they display high structural diversity. Numerous rearrangements due to homologous and nonhomologous recombination, deletions and segmental duplications, and loss and gain of TEs are diverse sources of active genomic variation at this locus. Notably, we evidence a correlation between the presence of ZAM and Idefix in this piRNA cluster and their silencing. They are absent from flam in the strain where they are derepressed. We show that, unexpectedly, more than half of the flam locus results from recent TE insertions and that most of the elements concerned are prone to horizontal transfer between species of the melanogaster subgroup. We build a model showing how such high and constant dynamics of a piRNA master locus open the way to continual emergence of new patterns of piRNA biogenesis leading to changes in the level of transposition control. PMID:24248389

  14. Small angle neutron scattering on a fast-cooled liquid crystal: MBBA

    International Nuclear Information System (INIS)

    The medium range order was studied in the non-crystalline solid phases of the fast-cooled nematic liquid crystal MBBA by small angle scattering of neutrons. In agreement with theoretical predictions, anisotropic intensity distribution was found at 0<0.005 nmsup(-1) on the magnetic field aligned sample. Bragg-reflections were also observed around 0.037 nmsup(-1) as a consequence of the evolution of smectic-type structures connected with the gradual relaxation in these solid phases. (author)

  15. Future evolution of distributed systems for smart grid - The challenges and opportunities to using decentralized energy system

    Science.gov (United States)

    Konopko, Joanna

    2015-12-01

    A decentralized energy system is a relatively new approach in the power industry. Decentralized energy systems provide promising opportunities for deploying renewable energy sources locally available as well as for expanding access to clean energy services to remote communities. The electricity system of the future must produce and distribute electricity that is reliable and affordable. To accomplish these goals, both the electricity grid and the existing regulatory system must be smarter. In this paper, the major issues and challenges in distributed systems for smart grid are discussed and future trends are presented. The smart grid technologies and distributed generation systems are explored. A general overview of the comparison of the traditional grid and smart grid is also included.

  16. Properties of field quantum entropy evolution in the Jaynes-Cummings model with initial squeezed coherent states field

    Institute of Scientific and Technical Information of China (English)

    Liu Wang-Yun; An Yu-Ying; Yang Zhi-Yong

    2007-01-01

    The properties of the field quantum entropy evolution in a system of a single-mode squeezed coherent state field interacting with a two-level atom is studied by utilizing the complete quantum theory, and we focus our attention on the discussion of the influences of field squeezing parameter γ, atomic distribution angle θ and coupling strength g between the field and the atom on the properties of the evolution of field quantum entropy. The results obtained from numerical calculation indicate that the amplitude of oscillation of field quantum entropy evolution decreases with the increasing of squeezing parameter γ, and that both atomic distribution angle θ and coupling strength g between the field and the atom can influence the periodicity of field quantum entropy evolution.

  17. Operando magnetic resonance: monitoring the evolution of conversion and product distribution during the heterogeneous catalytic ethene oligomerisation reaction.

    Science.gov (United States)

    Roberts, S Tegan; Renshaw, Matthew P; Lutecki, Michal; McGregor, James; Sederman, Andrew J; Mantle, Mick D; Gladden, Lynn F

    2013-11-18

    Operando magnetic resonance (MR) spectroscopy has been used to follow an ethene oligomerisation reaction performed at 110 °C, 28 barg over a 1 wt% Ni/SiO2-Al2O3 catalyst. Spectra acquired over the timecourse of the reaction allow the calculation of conversion and product distribution as a function of time-on-stream. PMID:24088715

  18. Matrix Structure Evolution and Nanoreinforcement Distribution in Mechanically Milled and Spark Plasma Sintered Al-SiC Nanocomposites

    Directory of Open Access Journals (Sweden)

    Nouari Saheb

    2014-09-01

    Full Text Available Development of homogenous metal matrix nanocomposites with uniform distribution of nanoreinforcement, preserved matrix nanostructure features, and improved properties, was possible by means of innovative processing techniques. In this work, Al-SiC nanocomposites were synthesized by mechanical milling and consolidated through spark plasma sintering. Field Emission Scanning Electron Microscope (FE-SEM with Energy Dispersive X-ray Spectroscopy (EDS facility was used for the characterization of the extent of SiC particles’ distribution in the mechanically milled powders and spark plasma sintered samples. The change of the matrix crystallite size and lattice strain during milling and sintering was followed through X-ray diffraction (XRD. The density and hardness of the developed materials were evaluated as function of SiC content at fixed sintering conditions using a densimeter and a digital microhardness tester, respectively. It was found that milling for 24 h led to uniform distribution of SiC nanoreinforcement, reduced particle size and crystallite size of the aluminum matrix, and increased lattice strain. The presence and amount of SiC reinforcement enhanced the milling effect. The uniform distribution of SiC achieved by mechanical milling was maintained in sintered samples. Sintering led to the increase in the crystallite size of the aluminum matrix; however, it remained less than 100 nm in the composite containing 10 wt.% SiC. Density and hardness of sintered nanocomposites were reported and compared with those published in the literature.

  19. Evolution and Distribution of Hydrolytic Enzyme Activities during Preharvest Sprouting of Wheat (Triticum aestivum) in the Field.

    Science.gov (United States)

    Olaerts, Heleen; Roye, Chiara; Derde, Liesbeth J; Sinnaeve, Georges; Meza, Walter R; Bodson, Bernard; Courtin, Christophe M

    2016-07-20

    To date, research on preharvest sprouted (PHS) wheat has mostly been conducted on kernels germinated under laboratory conditions, which differ widely from conditions in the field. To obtain detailed knowledge of the evolution of hydrolytic enzyme activities in PHS wheat (Triticum aestivum), a broad collection of samples from three varieties was obtained by harvesting before, at, and after maturity. Delaying harvest time coupled with periods of heavy rainfall caused sprouting in the kernels, observed as a drop in Falling Number and an increase in α-amylase activity. The appearance of α- and β-amylase, peptidase, and endoxylanase activity during field sprouting was independent from each other. Consequently, Falling Number could not be used to predict activity of other hydrolytic enzymes. When differentiating endogenous from kernel-associated microbial enzymes, results showed that α- and β-amylase and peptidase activity of PHS kernels were predominantly of endogenous origin, whereas endoxylanase activity was largely from microbial origin. PMID:27341479

  20. Large Piwinski angle

    CERN Document Server

    Abelleira, J L; Bhat, C; Cornelis, K; De Maria, R; Fartoukh, S; Giachino, R; Holzer, E B; Lamont, M; Mastoridis, T; Macpherson, A; Papotti, G; Pieloni, T; Roncarolo, F; Roy, G; Salvachua, B; Valuch, D; Zimmermann, F; Ohmi, K

    2012-01-01

    Two high brightness bunches per beam were collided at injection energy with varying spectrometer strength in IP8 so that the corresponding Piwinski angle changed from about 1.2–1.3 to 0.2. One of the two bunches colliding in IP8 also collided in IPs 1 and 5, increasing its tune spread. A Piwinski angle of 1.2 is the biggest value ever achieved in a hadron collider. The goal of this experiemnt had been to investigate the influence of this parameter on the luminosity lifetime, beam lifetime and emittance growth rate. Due to technical problems and unavailability of luminosity signals from CMS this goal was only partially accomplished.

  1. Why are angles misperceived?

    OpenAIRE

    Nundy, Surajit; Lotto, Beau; Coppola, David; Shimpi, Amita; Purves, Dale

    2000-01-01

    Although it has long been apparent that observers tend to overestimate the magnitude of acute angles and underestimate obtuse ones, there is no consensus about why such distortions are seen. Geometrical modeling combined with psychophysical testing of human subjects indicates that these misperceptions are the result of an empirical strategy that resolves the inherent ambiguity of angular stimuli by generating percepts of the past significance of the stimulus rather than the geometry of its re...

  2. Angle states in quantum mechanics

    Science.gov (United States)

    de la Torre, A. C.; Iguain, J. L.

    1998-12-01

    Angle states and angle operators are defined for a system with arbitrary angular momentum. They provide a reasonable formalization of the concept of angle provided that we accept that the angular orientation is quantized. The angle operator is the generator of boosts in angular momentum and is, almost everywhere, linearly related to the logarithm of the shift operator. Angle states for fermions and bosons behave differently under parity transformation.

  3. Holocene sub centennial evolution of Atlantic water inflow and sea ice distribution in the western Barents Sea

    Directory of Open Access Journals (Sweden)

    S. M. P. Berben

    2013-08-01

    Full Text Available In order to elucidate a continuous Holocene high resolution record of past variability of Atlantic water inflow and sea ice distribution, we investigate in this study a marine sediment core (JM09-KA11-GC from the Kveithola Trough, western Barents Sea margin which is influenced by the north flowing North Atlantic Current (NAC. The depth-age model for JM09-KA11-GC was constructed from 9 14C AMS dates and shows sediment accumulation rates from 0.04 to 0.67 mm yr−1, enabling a sub centennial resolution for most of the core. Planktic foraminifera, stable isotopes and biomarkers from sea ice diatoms and phytoplankton were analysed in order to reconstruct subsurface temperatures and sea ice distribution. Throughout the early part of the Holocene (11 900–6900 cal yr BP, the foraminiferal fauna is dominated by the polar Neogloboquadrina pachyderma (sinistral and the biomarkers show an influence of seasonal sea ice. Between 11 300 and 11 100 cal yr BP, a clear cooling is shown both by fauna and stable isotope data corresponding to the so-called Preboreal Oscillation. After 6900 cal yr BP the subpolar Turborotalita quinqueloba becomes the most frequent species, reflecting a stable Atlantic water inflow. Subsurface temperatures reach 6 °C and biomarker content indicates open water with mainly ice-free conditions. During the last 1100 cal yr BP, biomarker abundances and distributions show the re-appearance of low frequency seasonal sea ice and the planktic fauna show a reduced salinity in the subsurface water. No apparent temperature decrease is observed during this interval, but the rapidly fluctuating fauna and biomarker distributions indicate more unstable conditions.

  4. Energy-efficiency and Environmental Policies & Income Supplements in the UK: Evolution and Distributional Impacts on Domestic Energy Bills

    OpenAIRE

    Mallika Chawla; Michael G. Pollitt

    2013-01-01

    The paper examines the financial costs of energy-efficiency and environmental policies that directly affect domestic electricity and gas bills in the UK over time. It also attempts to work out the current distributional impacts of these policies and others that act as income supplements thereby presenting a consistent picture across time and income deciles. Figures suggest that between 2000 and 2011, the percentage share of policy costs in typical domestic electricity and gas bills rose by 14...

  5. Regional distribution and layout evolution of technological innovation in the new energy electric vehicles industry of China

    OpenAIRE

    Bao-Jun Tang; Xi Zheng; Ke Wang

    2013-01-01

    Based on the initial stage situation of new energy electric vehicles (electric vehicles) industry in China, this paper uses patents retrieval and literatures polymerization methods to analyze the technological innovation status quo and the regional distribution features in the electric vehicles industry at home and abroad. Then, the data envelopment analysis (DEA) method is applied to quantifiably evaluate technological innovation efficiency of the 17 major producing areas of electric vehicle...

  6. The distribution and evolution of fluid pressure and its influence on natural gas accumulation in the Upper Paleozoic of Shenmu-Yulin area, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    WANG; ZhenLiang; CHEN; HeLi

    2007-01-01

    On the basis of measuring the pressure distribution and analyzing its origin in the Carboniferous and Permian of Shenmu-Yulin area, the evolution history of ancient pressure is restored mainly by means of the basin numerical simulation technique, in which the paleo-pressure has been constrained by the compaction restoration and the examination of fluid inclusion temperature and pressure. Then the development and evolution history of abnormal pressure and its effect on gas migration and accumulation are investigated. Studies show that the pressure in southeastern and northwestern parts of studied area is near to hydrostatic pressure, whereas in the remainder vast area the pressure is lower than the hydrostatic pressure, which is caused by difficulty to measure pressure accurately in tight reservoir bed, the calculating error caused by in-coordinate between topography relief and surface of water potential, pressure lessening due to formation arising and erosion. There are geological factors beneficial to forming abnormal high pressure in the Upper Palaeozoic. On the distraction of measured pressure, paleo-pressure data from compaction restoration and fluid inclusion temperature and pressure exa- mining, the evolution history of ancient pressure is restored by the basin numerical simulation technique. It is pointed out that there are at least two high peaks of overpressure in which the highest value of excess pressure could be 5 to 25 MPa. Major gas accumulated in main producing bed of Shanxi Fm (P1s) and lower Shihezi Fm (P2x), because of two-fold control from capillary barrier and overpressure seal in upper Shihezi Fm (P2s). In the middle and southern districts, the two periods of Later Jurassic to the middle of Early Cretaceous, and middle of Later Cretaceous to Palaeocene are main periods of gas migration and accumulation, while they belong to readjustment period of gas reservoirs after middle of Neocene.

  7. A new method to estimate local pitch angles in spiral galaxies: Application to spiral arms and feathers in M81 and M51

    International Nuclear Information System (INIS)

    We examine 8 μm IRAC images of the grand design two-arm spiral galaxies M81 and M51 using a new method whereby pitch angles are locally determined as a function of scale and position, in contrast to traditional Fourier transform spectral analyses which fit to average pitch angles for whole galaxies. The new analysis is based on a correlation between pieces of a galaxy in circular windows of (lnR,θ) space and logarithmic spirals with various pitch angles. The diameter of the windows is varied to study different scales. The result is a best-fit pitch angle to the spiral structure as a function of position and scale, or a distribution function of pitch angles as a function of scale for a given galactic region or area. We apply the method to determine the distribution of pitch angles in the arm and interarm regions of these two galaxies. In the arms, the method reproduces the known pitch angles for the main spirals on a large scale, but also shows higher pitch angles on smaller scales resulting from dust feathers. For the interarms, there is a broad distribution of pitch angles representing the continuation and evolution of the spiral arm feathers as the flow moves into the interarm regions. Our method shows a multiplicity of spiral structures on different scales, as expected from gas flow processes in a gravitating, turbulent and shearing interstellar medium. We also present results for M81 using classical 1D and 2D Fourier transforms, together with a new correlation method, which shows good agreement with conventional 2D Fourier transforms.

  8. A new method to estimate local pitch angles in spiral galaxies: Application to spiral arms and feathers in M81 and M51

    Energy Technology Data Exchange (ETDEWEB)

    Puerari, Ivânio [Instituto Nacional de Astrofísica, Optica y Electrónica, Calle Luis Enrique Erro 1, 72840 Santa María Tonantzintla, Puebla (Mexico); Elmegreen, Bruce G. [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Block, David L., E-mail: puerari@inaoep.mx [School of Computational and Applied Mathematics, University of Witwatersrand, Private Bag 3, WITS 2050 (South Africa)

    2014-12-01

    We examine 8 μm IRAC images of the grand design two-arm spiral galaxies M81 and M51 using a new method whereby pitch angles are locally determined as a function of scale and position, in contrast to traditional Fourier transform spectral analyses which fit to average pitch angles for whole galaxies. The new analysis is based on a correlation between pieces of a galaxy in circular windows of (lnR,θ) space and logarithmic spirals with various pitch angles. The diameter of the windows is varied to study different scales. The result is a best-fit pitch angle to the spiral structure as a function of position and scale, or a distribution function of pitch angles as a function of scale for a given galactic region or area. We apply the method to determine the distribution of pitch angles in the arm and interarm regions of these two galaxies. In the arms, the method reproduces the known pitch angles for the main spirals on a large scale, but also shows higher pitch angles on smaller scales resulting from dust feathers. For the interarms, there is a broad distribution of pitch angles representing the continuation and evolution of the spiral arm feathers as the flow moves into the interarm regions. Our method shows a multiplicity of spiral structures on different scales, as expected from gas flow processes in a gravitating, turbulent and shearing interstellar medium. We also present results for M81 using classical 1D and 2D Fourier transforms, together with a new correlation method, which shows good agreement with conventional 2D Fourier transforms.

  9. A New Method to Estimate Local Pitch Angles in Spiral Galaxies: Application to Spiral Arms and Feathers in M81 and M51

    Science.gov (United States)

    Puerari, Ivânio; Elmegreen, Bruce G.; Block, David L.

    2014-12-01

    We examine 8 μ m IRAC images of the grand design two-arm spiral galaxies M81 and M51 using a new method whereby pitch angles are locally determined as a function of scale and position, in contrast to traditional Fourier transform spectral analyses which fit to average pitch angles for whole galaxies. The new analysis is based on a correlation between pieces of a galaxy in circular windows of (ln R,θ ) space and logarithmic spirals with various pitch angles. The diameter of the windows is varied to study different scales. The result is a best-fit pitch angle to the spiral structure as a function of position and scale, or a distribution function of pitch angles as a function of scale for a given galactic region or area. We apply the method to determine the distribution of pitch angles in the arm and interarm regions of these two galaxies. In the arms, the method reproduces the known pitch angles for the main spirals on a large scale, but also shows higher pitch angles on smaller scales resulting from dust feathers. For the interarms, there is a broad distribution of pitch angles representing the continuation and evolution of the spiral arm feathers as the flow moves into the interarm regions. Our method shows a multiplicity of spiral structures on different scales, as expected from gas flow processes in a gravitating, turbulent and shearing interstellar medium. We also present results for M81 using classical 1D and 2D Fourier transforms, together with a new correlation method, which shows good agreement with conventional 2D Fourier transforms.

  10. Spectrum parameter estimation in Brillouin scattering distributed temperature sensor based on cuckoo search algorithm combined with the improved differential evolution algorithm

    Science.gov (United States)

    Zhang, Yanjun; Yu, Chunjuan; Fu, Xinghu; Liu, Wenzhe; Bi, Weihong

    2015-12-01

    In the distributed optical fiber sensing system based on Brillouin scattering, strain and temperature are the main measuring parameters which can be obtained by analyzing the Brillouin center frequency shift. The novel algorithm which combines the cuckoo search algorithm (CS) with the improved differential evolution (IDE) algorithm is proposed for the Brillouin scattering parameter estimation. The CS-IDE algorithm is compared with CS algorithm and analyzed in different situation. The results show that both the CS and CS-IDE algorithm have very good convergence. The analysis reveals that the CS-IDE algorithm can extract the scattering spectrum features with different linear weight ratio, linewidth combination and SNR. Moreover, the BOTDR temperature measuring system based on electron optical frequency shift is set up to verify the effectiveness of the CS-IDE algorithm. Experimental results show that there is a good linear relationship between the Brillouin center frequency shift and temperature changes.

  11. Middle Stone Age (MSA) site distributions in eastern Africa and their relationship to Quaternary environmental change, refugia and the evolution of Homo sapiens

    Science.gov (United States)

    Basell, Laura S.

    2008-12-01

    This paper considers the evolution of Homo sapiens in eastern Africa in relation to refugia and bottlenecks around ˜200 ka BP, at a macro scale. Middle Stone Age (MSA) lithics, site distributions and locations are analysed in relation to palaeovegetation maps of the last glacial/interglacial cycle, which are used as a proxy for earlier climate cycles. A "push and pull" model is then postulated for the spread of Homo sapiens out of refugia in eastern Africa, involving both volcanism (push) and habitat availability (pull). A date within OIS 5 is suggested for this expansion to other parts of the continent, and potentially further afield, contrary to a frequently proposed expansion within OIS 3.

  12. 3D-HST + CANDELS: the Evolution of the Galaxy Size-mass Distribution Since Z=3

    Science.gov (United States)

    VanDerWel, A.; Franx, M.; vanDokkum, P. G.; Skelton, R. E.; Momcheva, I. G.; Whitaker, K. E.; Brammer, G. B.; Bell, E. F.; Rix, H.-W.; Wuyts, S.; Ferguson, H. C.; Holden, B. P.; Barro, G.; Koekemoer, A. M.; Chang, Yu-Yen; McGrath, E. J.; Haussler, B.; Dekel, A.; Behroozi, P.; Fumagalli, M.; Leja, J.; Lundgren, B. F.; Maseda, M. V.; Nelson, E. J.; Wake, D. A.

    2014-01-01

    Spectroscopic and photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift (z) range 0 3 x 10 (sup 9) solar masses, and steep, effective radius in proportion to mass of a black hole (sup 0.75), for early-type galaxies with stellar mass > 2 x 10 (sup 10) solar masses. The intrinsic scatter is approximately or less than 0.2 decimal exponents for all galaxy types and redshifts. For late-type galaxies, the logarithmic size distribution is not symmetric, but skewed toward small sizes: at all redshifts and masses a tail of small late-type galaxies exists that overlaps in size with the early-type galaxy population. The number density of massive (approximately 10 (sup 11) solar masses), compact (effective radius less than 2 kiloparsecs) early-type galaxies increases from z = 3 to z = 1.5 - 2 and then strongly decreases at later cosmic times.

  13. A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Bugge, L; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F R; Chapkin, M M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crawley, B; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L S; Di Ciaccio, Lucia; Di Simone, A; Doroba, K; Drees, J; Dris, M; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J A; Gandelman, M; García, C; Gavillet, P; Gazis, E N; Geralis, T; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Hansen, J; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E C; Kernel, G; Kersevan, Borut P; Kiiskinen, A P; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Meyer, W T; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L M; Murray, W; Muryn, B; Myatt, Gerald; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Pukhaeva, N; Pullia, Antonio; Rames, J; Ramler, L; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Rosenberg, E I; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sissakian, A N; Smadja, G; Smirnova, O G; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L G; Tobin, M; Todorovova, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Lysebetten, A; Van Remortel, N; Van Vulpen, I B; Vegni, G; Veloso, F; Venus, W A; Verbeure, F; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, P; Zavrtanik, D; Zimin, N I; Zinchenko, A I; Zupan, M

    2003-01-01

    Infrared and collinear safe event shape distributions and their mean values are determined in e+e− collisions at centre-of-mass energies between 45 and 202 GeV. A phenomenological analysis based on power correction models including hadron mass e ects for both differential distributions and mean values is presented. Using power corrections, s is extracted from the mean values and shapes. In an alternative approach, renormalisation group invariance (RGI) is used as an explicit constraint, leading to a consistent description of mean values without the need for sizeable power corrections. The QCD beta-function is precisely measured using this approach. From the DELPHI data on Thrust, including data from low energy experiments, one finds beta0 = 7:86 +- 0:32 for the one loop coefficient of the beta-function or, assuming QCD, nf = 4:75 +- 0:44 for the number of active flavours. These values agree well with the QCD expectation of beta0 = 7:67 and nf = 5. A direct measurement of the full logarithmic energy ...

  14. Tracking the Distribution of 26Al and 60Fe during the Early Phases of Star and Disk Evolution

    Science.gov (United States)

    Kuffmeier, Michael; Frostholm Mogensen, Troels; Haugbølle, Troels; Bizzarro, Martin; Nordlund, Åke

    2016-07-01

    The short-lived 26Al and 60Fe radionuclides are synthesized and expelled into the interstellar medium by core-collapse supernova events. The solar system’s first solids, calcium–aluminum refractory inclusions (CAIs), contain evidence for the former presence of the 26 Al nuclide defining the canonical 26Al/27 Al ratio of ∼ 5× {10}-5. A different class of objects temporally related to canonical CAIs are CAIs with fractionation and unidentified nuclear effects (FUN CAIs), which record a low initial 26Al/27Al of 10‑6. The contrasting level of 26Al between these objects is often interpreted as reflecting the admixing of the 26Al nuclides during the early formative phase of the Sun. We use giant molecular cloud scale adaptive mesh-refinement numerical simulations to trace the abundance of 26Al and 60Fe in star-forming gas during the early stages of accretion of individual low-mass protostars. We find that the 26Al/27Al and 60Fe/56Fe ratios of accreting gas within a vicinity of 1000 au of the stars follow the predicted decay curves of the initial abundances at the time of star formation without evidence of spatial or temporal heterogeneities for the first 100 kyr of star formation. Therefore, the observed differences in 26Al/27Al ratios between FUN and canonical CAIs are likely not caused by admixing of supernova material during the early evolution of the proto-Sun. Selective thermal processing of dust grains is a more viable scenario to account for the heterogeneity in 26Al/27Al ratios at the time of solar system formation.

  15. Cerebellopontine angle Hodgkin's disease

    International Nuclear Information System (INIS)

    Intracranial Hodgkin's disease is a rare site of involvement, and even more rare is its presentation as a cerebellopontine angle mass. It can be difficult to diagnose especially when recurrent tumors occur because both CT and lumbar puncture have been shown to have a relatively low yield. Gadolinium-enhanced MRI is more sensitive. It is concluded that while the imaging findings can be non-specific, the rapid response to therapy (steroids) may provide a clue to diagnosis. Copyright (1999) Blackwell Science Pty Ltd

  16. Critical angle laser refractometer

    International Nuclear Information System (INIS)

    A simple laser refractometer based on the detection of the critical angle for liquids is presented. The calibrated refractometer presents up to 0.000 11 of uncertainty when the refractive index is in the range between 1.300 00 and 1.340 00. The experimental setup is easy to construct and the material needed is available at most optics laboratories. The calibration method is simple and can be used in other devices. The refractive index measurements in aqueous solutions of sodium chloride were carried out to test the device and a linear dependence between the refractive index and the salt concentration was found

  17. Angle-Resolved Spectroscopy of Parametric Fluorescence

    CERN Document Server

    Hsu, Feng-kuo

    2013-01-01

    The parametric fluorescence from a nonlinear crystal forms a conical radiation pattern. We measure the angular and spectral distributions of parametric fluorescence in a beta-barium borate crystal pumped by a 405-nm diode laser employing angle-resolved imaging spectroscopy. The experimental angle-resolved spectra and the generation efficiency of parametric down conversion are compared with a plane-wave theoretical analysis. The parametric fluorescence is used as a broadband light source for the calibration of the instrument spectral response function in the wavelength range from 450 to 1000 nm.

  18. 从认识论看创面敷料的演变与进步%Analysis the Evolution and Progress of Wound Dressing in Medicine History from the Angle of Epistemology

    Institute of Scientific and Technical Information of China (English)

    贾赤宇

    2011-01-01

    辩证唯物主义的认识论认为,人类认识的一般秩序是:“个性——共性——个性”.认识的发展要经过“实践、认识、再实践、再认识”的循环往复、以至无穷的过程.纵观创面敷料的演变及进展,完全遵循和验证了这一真理.%The epistemological thought of dialectical materialism considers that the general order of human understanding is; "Character- common- individuality". The full development of cognition usually go through the "practice, knowledge, re - practice, and re -understanding of practice" circle, and endless process. Look at the evolution and progress process of wound dressings in medicine history, we can draw a conclusion that it is follow the track of epistemology.

  19. THE EVOLUTION AND THE FUTURE ROLE OF THE BRANCH IN DISTRIBUTION OF THE BANKING PRODUCTS AND SERVICES

    Directory of Open Access Journals (Sweden)

    CĂTĂLIN NICOLAE BULGĂREA

    2011-01-01

    Full Text Available Debate about the role of the branch office in the retail banking business is nothing new. The discussion of branch existence has been going on since the appearance of the internet, mobile phone. Despite the development of new distribution channels and falling number of customers, the branch is by no means dead! In fact, surveys and studies have consistently shown that it remains the customers’ preferred channel: they still value face-toface discussions with their bank officer. Currently the branches contribute to about 85% of sales. The branch needs to evolve so that it provides customers with a powerful and attractive alternative to the other channels that are appearing. What is the role of branch in the multichannel banking? Banks should have the ability to deliver the right service, at the right time in the right channel.

  20. An integrated approach to coastal erosion problems in northern Tuscany (Italy): Littoral morphological evolution and cell distribution

    Science.gov (United States)

    Anfuso, G.; Pranzini, E.; Vitale, G.

    2011-06-01

    Occupation of the coast has significantly increased in recent decades, mostly due to a greater demand for recreation and tourism. Today, erosion threatens many human-made structures and activities, requiring an integrated approach for the understanding of coastal dynamics and identification of alternatives to associated problems. This study investigates a 64 km-long coastal physiographic unit in the northern microtidal littoral of Tuscany (Italy). Vertical aerial photographs and direct field surveys were used to retrieve changes in shoreline position over 1938-1997 and 1997-2005 time intervals. Significant beach accretion was observed during the first period updrift of Carrara (84 m) and Viareggio (280 m) harbours and at Marina di Pietrasanta (100 m), whereas severe erosion occurred downcoast of Carrara harbour (- 130 m, at Marina dei Ronchi) and on the northern side of Arno river mouth (- 400 m). Similar trends were observed between 1997 and 2005; beach slope between the 1997 shoreline position and the closure depth correlated well with the distribution of erosion/accretion patterns from the 1938-1997 period (slopes were lower in eroded areas than at sites under accretion). Longshore distribution of erosion/accretion patterns was controlled by coastal compartmentalisation. Three of the main littoral cells were mostly formed by natural limits (i.e., Punta Bianca promontory, Marina di Pietrasanta, the Arno river mouth and the port of Livorno). Several sub-cells were created within these cells due to the introduction of human-made structures (such as Carrara and Viareggio harbours), which formed artificial fixed limits that allowed the transport of sediments (exclusively fines) in one direction only. Results will help improve the understanding of coastal processes and manage littoral sediment transport in a sustainable manner. This will reduce the need for structural interventions, such as breakwaters and groynes, which in the past decades prevented coastal retreat

  1. Seasonal and spatial evolution of trihalomethanes in a drinking water distribution system according to the treatment process.

    Science.gov (United States)

    Domínguez-Tello, A; Arias-Borrego, A; García-Barrera, Tamara; Gómez-Ariza, J L

    2015-11-01

    This paper comparatively shows the influence of four water treatment processes on the formation of trihalomethanes (THMs) in a water distribution system. The study was performed from February 2005 to January 2012 with analytical data of 600 samples taken in Aljaraque water treatment plant (WTP) and 16 locations along the water distribution system (WDS) in the region of Andévalo and the coast of Huelva (southwest Spain), a region with significant seasonal and population changes. The comparison of results in the four different processes studied indicated a clear link of the treatment process with the formation of THM along the WDS. The most effective treatment process is preozonation and activated carbon filtration (P3), which is also the most stable under summer temperatures. Experiments also show low levels of THMs with the conventional process of preoxidation with potassium permanganate (P4), delaying the chlorination to the end of the WTP; however, this simple and economical treatment process is less effective and less stable than P3. In this study, strong seasonal variations were obtained (increase of THM from winter to summer of 1.17 to 1.85 times) and a strong spatial variation (1.1 to 1.7 times from WTP to end points of WDS) which largely depends on the treatment process applied. There was also a strong correlation between THM levels and water temperature, contact time and pH. On the other hand, it was found that THM formation is not proportional to the applied chlorine dose in the treatment process, but there is a direct relationship with the accumulated dose of chlorine. Finally, predictive models based on multiple linear regressions are proposed for each treatment process. PMID:26431706

  2. Variable angle correlation spectroscopy

    International Nuclear Information System (INIS)

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system

  3. Variable angle correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y K [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  4. Angle performance on optima MDxt

    International Nuclear Information System (INIS)

    Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt’s angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16° (1σ). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1° (1σ).

  5. The stellar mass distribution of S$^4$G disk galaxies and the signatures of bar-induced secular evolution

    CERN Document Server

    Díaz-García, Simón; Laurikainen, Eija

    2016-01-01

    We use 3.6 $\\mu$m photometry from the Spitzer Survey of Stellar Structure in Galaxies (S$^{4}$G) to trace the stellar distribution in nearby disk galaxies ($z\\approx0$) with total stellar masses $10^{8.5}\\lesssim M_{\\ast}/M_{\\odot}\\lesssim10^{11}$ and mid-IR Hubble types $-3 \\le T \\le 10$, and to provide observational constraints for galaxy formation models to be checked against. For 1154 galaxies with disk inclinations lower than $65^{\\circ}$, we Fourier decompose and rescale their images to a common frame determined (i) by the size in physical units, (ii) by their disk scalelength, and for 748 barred galaxies (iii) by both the length and orientation of their bars. We stack the resized density profiles and images to obtain statistically representative average stellar disks and bars in bins of $M_{\\ast}$ and $T$. We also calculate the mean stellar contribution to the circular velocity. We infer the gravitational potentials from the synthetic bars to obtain the tangential-to-radial force ratio ($Q_{\\rm T}$) an...

  6. Gaia: focus, straylight and basic angle

    CERN Document Server

    Mora, A; Bombrun, A; Boyadian, J; Chassat, F; Corberand, P; Davidson, M; Doyle, D; Escolar, D; Gielesen, W L M; Guilpain, T; Hernandez, J; Kirschner, V; Klioner, S A; Koeck, C; Laine, B; Lindegren, L; Serpell, E; Tatry, P; Thoral, P

    2016-01-01

    The Gaia all-sky astrometric survey is challenged by several issues affecting the spacecraft stability. Amongst them, we find the focus evolution, straylight and basic angle variations Contrary to pre-launch expectations, the image quality is continuously evolving, during commissioning and the nominal mission. Payload decontaminations and wavefront sensor assisted refocuses have been carried out to recover optimum performance. An ESA-Airbus DS working group analysed the straylight and basic angle issues and worked on a detailed root cause analysis. In parallel, the Gaia scientists have also analysed the data, most notably comparing the BAM signal to global astrometric solutions, with remarkable agreement. In this contribution, a status review of these issues will be provided, with emphasis on the mitigation schemes and the lessons learned for future space missions where extreme stability is a key requirement.

  7. Freshwater biogeography and limnological evolution of the Tibetan Plateau--insights from a plateau-wide distributed gastropod taxon (Radix spp..

    Directory of Open Access Journals (Sweden)

    Parm Viktor von Oheimb

    Full Text Available BACKGROUND: The Tibetan Plateau is not only the highest and largest plateau on earth; it is also home to numerous freshwater lakes potentially harbouring endemic faunal elements. As it remains largely unknown whether these lakes have continuously existed during the Last Glacial Maximum (LGM, questions arise as to whether taxa have been able to exist on the plateau since before the latest Pleistocene, from where and how often the plateau was colonized, and by which mechanisms organisms conquered remote high altitude lentic freshwater systems. In this study, species of the plateau-wide distributed freshwater gastropod genus Radix are used to answer these biogeographical questions. METHODOLOGY/PRINCIPAL FINDINGS: Based on a broad spatial sampling of Radix spp. on the Tibetan Plateau, and phylogenetic analyses of mtDNA sequence data, three probably endemic and one widespread major Radix clade could be identified on the plateau. Two of the endemic clades show a remarkably high genetic diversity, indicating a relatively great phylogenetic age. Phylogeographical analyses of individuals belonging to the most widely distributed clade indicate that intra-plateau distribution cannot be explained by drainage-related dispersal alone. CONCLUSIONS/SIGNIFICANCE: Our study reveals that Radix spp. persisted throughout the LGM on the Tibetan Plateau. Therefore, we assume the continuous existence of suitable water bodies during that time. The extant Radix diversity on the plateau might have been caused by multiple colonization events combined with a relatively long intra-plateau evolution. At least one colonization event has a Palaearctic origin. In contrast to freshwater fishes, passive dispersal, probably by water birds, might be an important mechanism for conquering remote areas on the plateau. Patterns found in Radix spp. are shared with some terrestrial plateau taxa, indicating that Radix may be a suitable model taxon for inferring general patterns of biotic

  8. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  9. Modelling of surface evolution of rough surface on divertor target in fusion devices

    International Nuclear Information System (INIS)

    Highlights: • We study the surface evolution of rough surface on divertor target in fusion devices. • The effects of gyration motion and E × B drift affect 3D angular distribution. • A larger magnetic field angle leads to a reduced net eroded areal density. • The rough surface evolution affects the physical sputtering yield. - Abstract: The 3D Monte-Carlo code SURO has been used to study the surface evolution of rough surface on the divertor target in fusion devices. The edge plasma at divertor region is modelled by the SDPIC code and used as input data for SURO. Coupled with SDPIC, SURO can perform more sophisticated simulations to calculate the local angle and surface evolution of rough surface. The simulation results show that the incident direction of magnetic field, gyration and E × B force has a significant impact on 3D angular distribution of background plasma and accordingly on the erosion of rough surface. The net eroded areal density of rough surface is studied by varying the magnetic field angle with surface normal. The evolution of the microscopic morphology of rough surface can lead to a significant change in the physical sputtering yield

  10. Modelling of surface evolution of rough surface on divertor target in fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Shuyu, E-mail: daishuyu@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Liu, Shengguang; Sun, Jizhong [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Kirschner, A. [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, D-52425 Jülich (Germany); Kawamura, G. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Tskhakaya, D. [Association EURATOM – öAW, Institute of Applied Physics, TU Wien, A-1040 Vienna (Austria); Ding, Rui; Luo, Guangnan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Wang, Dezhen, E-mail: wangdez@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2015-08-15

    Highlights: • We study the surface evolution of rough surface on divertor target in fusion devices. • The effects of gyration motion and E × B drift affect 3D angular distribution. • A larger magnetic field angle leads to a reduced net eroded areal density. • The rough surface evolution affects the physical sputtering yield. - Abstract: The 3D Monte-Carlo code SURO has been used to study the surface evolution of rough surface on the divertor target in fusion devices. The edge plasma at divertor region is modelled by the SDPIC code and used as input data for SURO. Coupled with SDPIC, SURO can perform more sophisticated simulations to calculate the local angle and surface evolution of rough surface. The simulation results show that the incident direction of magnetic field, gyration and E × B force has a significant impact on 3D angular distribution of background plasma and accordingly on the erosion of rough surface. The net eroded areal density of rough surface is studied by varying the magnetic field angle with surface normal. The evolution of the microscopic morphology of rough surface can lead to a significant change in the physical sputtering yield.

  11. Effects of the rotation angle on surface plasmon coupling of nanoprisms

    Science.gov (United States)

    Chien, Miao-Hsuan; Nien, Li-Wei; Chao, Bo-Kai; Li, Jia-Han; Hsueh, Chun-Hway

    2016-02-01

    We studied the effects of relative orientation of bowtie nanostructures on the plasmon resonance both experimentally and theoretically in this work. Specifically, we fabricated gold bowtie nanoantennas with rotated nanoprisms, measured the near-field and the far-field resonance behaviors using Raman spectroscopy and scattering microspectroscopy, and simulated the effects of the rotation angle on the localized surface plasmonic resonance using finite-difference time-domain simulations. In addition to the widely-discussed dipolar resonance in regular bowtie nanostructures, defined as tip-mode resonance in the present study, the excitations of edge-mode resonance were discovered under certain rotation angles of nanoprisms. Because of the resonances of different modes at different wavelengths, two different incident laser sources were used to measure the Raman spectra to provide evidence for the evolution of different resonance modes. Also, both the tip-mode and edge-mode resonances were verified by the simulated charge density distribution and their trends were discussed. Based on the discovered trend, a plasmon protractor was created with a near-exponential decay relationship between the relative resonance wavelength shift and cosine of the rotation angle. A plasmon hybridization model was also proposed for rotated bowties to explain the coupling between nanoprisms during rotation.We studied the effects of relative orientation of bowtie nanostructures on the plasmon resonance both experimentally and theoretically in this work. Specifically, we fabricated gold bowtie nanoantennas with rotated nanoprisms, measured the near-field and the far-field resonance behaviors using Raman spectroscopy and scattering microspectroscopy, and simulated the effects of the rotation angle on the localized surface plasmonic resonance using finite-difference time-domain simulations. In addition to the widely-discussed dipolar resonance in regular bowtie nanostructures, defined as tip

  12. Modeling small angle scattering data using FISH

    International Nuclear Information System (INIS)

    Full text: Small angle neutron scattering (SANS) and small angle x-ray scattering (SAXS) are important techniques for the characterisation of samples on the nanometer scale. From the scattered intensity pattern information about the sample such as particle size distribution, concentration and particle interaction can be determined. Since the experimental data is in reciprocal space and information is needed about real space, modeling of the scattering data to obtain parameters is extremely important and several paradigms are available. The use of computer programs to analyze the data is imperative for a robust description of the sample to be obtained. This presentation gives an overview of the SAS process and describes the data-modeling program FISH, written by R. Heenan 1983-2000. The results of using FISH to obtain the particle size distribution of bubbles in the aluminum hydrogen system and other systems of interest are described. Copyright (2002) Australian X-ray Analytical Association Inc

  13. Characterization of Y2O3 Particle Distribution in Oxide Dispersion Strengthened Eurofer Steel for Nuclear Applications by Means of Small-Angle Neutron Scattering (SANS) and of Neutron Diffraction

    International Nuclear Information System (INIS)

    This report summarizes the scientific results obtained in the frame IAEA Agreement No. 16200/R0 4/5/2010 until May 2013. Small-angle neutron scattering (SANS) and neutron diffraction measurements have been carried out on Oxide Dispersion Strengthened (ODS) Eurofer97 and 14 Cr ferritic/martensitic steels, obtaining relevant information on their microstructure. Collaborative results have also been obtained with other CRP participants, concerning the optimization of SANS data analysis, compared SANS measurements on ODS material at different neutron sources and the characterization of H-loaded Zr tubes. (author)

  14. Hiss induced radiation belt electron loss timescales in the plasmasphere based on ray tracings of wave propagation angle

    Science.gov (United States)

    Zhou, C.; Ni, B.; Li, W.; Bortnik, J.; Gu, X.; Zhao, Z.

    2015-12-01

    Plasmaspheric hiss plays an important role in driving resonant scattering losses of radiation belt electrons and thereby largely controls the lifetimes of electrons in the plasmasphere. Besides the spectral information of waves, an accurate investigation of hiss induced radiation belt electron loss timescales requires the details of wave normal angle distribution during propagation along the field line, which however is difficult to obtain directly from in situ measurements but can be reasonably evaluated from ray tracing of hiss propagation on basis of reasonable setups of background field and plasma density. By assuming a nominal and suitable plasmapause location at L = 4.5, we report the ray tracing results of hiss wave propagation angles for various hiss wave frequencies at various L-shells in the plasmasphere. Subsequently, we construct the improved model of hiss wave normal angle distribution with dependence on both wave frequency, magnetic latitude and L-shell, which is used to compute the quasi-linear bounce-averaged rates of electron scattering due to plasmaspheric hiss and perform the pure pitch angle diffusion simulations. Hiss induced radiation belt electron loss timescales are then determined from the simulated temporal evolution of electron fluxes after reaching the equilibrium state, as a function of electron kinetic energy and L-shell, which is of importance for incorporation into future simulations of the radiation belt electron dynamics under various geomagnetic conditions to comprehend the exact contribution of plasmaspheric hiss.

  15. Protein Structure Idealization: How accurately is it possible to model protein structures with dihedral angles?

    OpenAIRE

    Cui, Xuefeng; Li, Shuai Cheng; Bu, Dongbo; Alipanahi, Babak; Li, Ming

    2013-01-01

    Previous studies show that the same type of bond lengths and angles fit Gaussian distributions well with small standard deviations on high resolution protein structure data. The mean values of these Gaussian distributions have been widely used as ideal bond lengths and angles in bioinformatics. However, we are not aware of any research done to evaluate how accurately we can model protein structures with dihedral angles and ideal bond lengths and angles. Here, we introduce the protein structur...

  16. Small angle neutron scattering

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of

  17. Small angle neutron scattering

    International Nuclear Information System (INIS)

    Small Angle Neutron Scattering (SANS) is a technique that enables to probe the 3-D structure of materials on a typical size range lying from about 1 nm up to a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nano-metric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area... ) through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons) make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some information that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer), form factor analysis (I(q→0), Guinier regime, intermediate regime, Porod regime, polydisperse system), structure factor analysis (2. Virial coefficient, integral equations, characterization of aggregates), and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast). It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of spectrometer

  18. Effect of heat treatment on pore structure in nanocrystalline NiO: A small angle neutron scattering study

    Indian Academy of Sciences (India)

    J Bahadur; D Sen; S Mazumder; S Ramanathan

    2008-11-01

    Nanocrystalline nickel oxide powders were calcined at 300, 600 and 900°C and pore structure evolution was followed by small angle neutron scattering (SANS). Pore size distributions at two widely separated size ranges have been revealed. Shrinkage of larger-sized pore with reduction in polydispersity has been observed with increasing heat treatment temperature. The pore structures at various heat treatment temperatures do not scale. This has been attributed to the grain boundary diffusion leading to an asymmetric shrinkage of the pores.

  19. On large angle multiple gluon radiation

    CERN Document Server

    Dokshitzer, Y L; Dokshitzer, Yu.L.

    2003-01-01

    Jet shape observables which involve measurements restricted to a part of phase space are sensitive to multiplication of soft gluon with large relative angles and give rise to specific single logarithmically enhanced (SL) terms (non-global logs). We consider associated distributions in two variables which combine measurement of a jet shape V in the whole phase space (global) and that of the transverse energy flow away from the jet direction, Eout (non-global). We show that associated distributions factorize into the global distribution in V and a factor that takes into account SL contributions from multi-gluon ``hedgehog'' configurations in all orders. The latter is the same that describes the single-variable Eout distribution, but evaluated at a rescaled energy VQ.

  20. Microstructure and texture evolution during continuous dynamic recrystallization at warm deformation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Mironov, S.Y.; Salishchev, G.A.; Zherebtsov, S.V. [Inst. of Metals Superplasticity Problems, RAS, Ufa (Russian Federation)

    2004-07-01

    The microstructure and texture evolutions in pure titanium during severe plastic deformation at T=400 C were investigated. Compressive deformation of prismatic samples was sequentially applied in three orthogonal directions up to 12 steps and a strain at each step of 40%. A radical microstructure refinement (from 20 to 0.2 {mu}m) during strain has been found. The features of the deformation structure are a high level of internal stresses, high density of dislocations, a large number of deformation induced boundaries and the presence of twins. It is shown that during strain there is a significant change in disorientation angles and axes of individual high angle grain boundaries. At the same time the total set of high angle boundaries - Misorientation Distribution Function (MDF) and texture - does not change significantly with strain. The reasons for the change in disorientation angles and axes at new deformation-induced boundaries during plastic flow are discussed. (orig.)

  1. Understanding evolution of product composition and volatility distribution through in-situ GC × GC analysis: a case study of longifolene ozonolysis

    Directory of Open Access Journals (Sweden)

    N. M. Donahue

    2011-06-01

    Full Text Available A method for predicting volatility and polarity based on chromatographic information was developed and applied to the smog chamber ozonolysis of the sesquiterpene longifolene. The products were collected and analyzed using a GC × GC Thermal Desorption Aerosol Gas Chromatograph/Mass Spectrometer (2D-TAG and a quadrupole Aerodyne Aerosol Mass Spectrometer (AMS. All the secondary organic aerosol (SOA was produced within the first half hour of the experiment. However, the oxidation level of the organic aerosol, as inferred from the fraction of ion m/z 44, suggested continued evolution of the SOA over the subsequent hours. Measurements of speciated organic compounds using 2D-TAG confirm that the composition of the particles changed over the course of the experiment. Nearly 200 oxidation products (thought to be mostly ketones and acids were observed with 2D-TAG, but most could not be identified definitively due to a lack of standards and the absence of likely sesquiterpene oxidation products in available mass spectral databases. To categorize the observed products, the vapor pressure and oxygen-to-carbon ratio (O/C of observed compounds were estimated based on their two-dimensional chromatographic retention times relative to those of known standards, establishing a retention time correlation (RTC method for using 2D-TAG to better constrain important modelling parameters. The product distribution continuously evolved in volatility and oxygenation during 5 h of oxidation. Using peak area as the best available proxy for mass, we conclude that the product mixture includes many non-negligible products; the most abundant 3 compounds accounted for only half of the total observed peak area and 80 % of peak area was spread across 15 compounds. The data provide evidence for three conclusions: (1 2D-TAG provides valuable volatility and oxygenation information even in the absence of definitive species identification, (2 complex particle-phase chemistry causes

  2. Understanding evolution of product composition and volatility distribution through in situ GC × GC analysis: a case study of longifolene ozonolysis

    Directory of Open Access Journals (Sweden)

    N. M. Donahue

    2011-01-01

    Full Text Available A method for predicting volatility and polarity based on chromatographic information was developed and applied to the smog chamber ozonolysis of the sesquiterpene longifolene. The products were collected and analyzed using a GC × GC Thermal Desorption Aerosol Gas Chromatograph/Mass Spectrometer (2D-TAG and a quadrupole Aerodyne Aerosol Mass Spectrometer (AMS. All the secondary organic aerosol (SOA was produced within the first half hour of the experiment. However, the oxidation level of the organic aerosol, as inferred from the fraction of ion m/z 44, suggested continued evolution of the SOA over the subsequent hours. Measurements of speciated organic compounds using 2D-TAG confirm that the composition of the particles changed over the course of the experiment. Nearly 200 oxidation products (thought to be mostly ketones and acids were observed with 2D-TAG, but most could not be identified definitively due to a lack of standards and the absence of likely sesquiterpene oxidation products in available mass spectral databases. To categorize the observed products, the vapor pressure and oxygen-to-carbon ratio (O/C of observed compounds were estimated based on their multi-dimensional chromatographic retention times relative to those of known standards, establishing a retention time correlation (RTC method for using 2D-TAG to better constrain important modelling parameters. The product distribution continuously evolved in volatility and oxygenation during 5 h of oxidation. Using peak area as the best available proxy for mass, we conclude that the product mixture includes many non-negligible products; the most abundant 3 compounds accounted for only half of the total observed peak area and 80% of peak area was spread across 15 compounds. The data provide evidence for three conclusions: (1 2D-TAG can provide valuable volatility and oxygenation information even in the absence of definitive species identification, (2 complex particle-phase chemistry

  3. The formation and evolution of Chepaizi-Mosuowan paleo-uplift and its control on the distributions of sedimentary facies in the Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Chepaizi-Mosuowan paleo-uplift is a large-scale uplift stretching across the Junggar Basin formed during the Yanshanian. It has experienced four evolutionary stages: the initial forming stage (J1), the intense development stage (J2+3), the waning and burial stage (K-E), and the tilting and extinction stage (N-Q). The most intense period of activities is the Middle Jurassic. Dur-ing the Early Jurassic, the Chepaizi-Mosuowan paleo-structure was a low amplitude uplift. Because of the subsequent strong uplifting during Middle-Late Jurassic, the Middle and Upper Jurassic were eroded. With the evolution of the Chepaizi-Mosuowan paleo-uplift, the sedimentary pattern of the basin changed, and the paleo-uplift separated the northern depositional systems from those in the south side. As a result, the basin tectonics controlled the distribution and evolution of the depositional systems. During Early Jurassic, while the paleo-uplift was low, its controlling effect on depositional systems was limited and sediments coming from the northwest could reach the central and southern parts of the basin. With the strong uplifting of the Chepaizi-Mosuowan paleo-structure during Middle-Late Jurassic, sediments from the northwest provenance could only deposit in the northern graben of the paleo-uplift. The intense erosion of the Middle-Upper Jurassic also changed the former sedimentary center of the basin into a source area, supplying sediments for grabens on both sides of the paleo-uplift. In the Cretaceous, regional subsidence caused the paleo-uplift to be buried again and subsequently sediments accumulated on top of it. The depositional facies are dominated by fluvial in the Early Cretaceous and shallow lacustrine to deltaic in the Late Cretaceous. In the history of the long-lasting development of this paleo-uplift, large-scale erosions of the paleohigh not only provided sufficient sediments to the center of the Junggar Basin, but also created favorable conditions for the formation

  4. Generalized parton distributions at large momentum transfer

    OpenAIRE

    Kroll, P.

    2001-01-01

    The role of generalized parton distributions in wide-angle exclusive reactions will be discussed. In contrast to deep virtual exclusive reactions the wide angle processes offer the possibility of investigating the generalized parton distributions at large momentum transfer.

  5. Spinning angle optical calibration apparatus

    Science.gov (United States)

    Beer, Stephen K.; Pratt, II, Harold R.

    1991-01-01

    An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

  6. Microstructure and texture evolution of commercial pure titanium deformed at elevated temperatures

    International Nuclear Information System (INIS)

    Microstructure and texture evolution of commercial pure titanium were investigated by electron backscattered diffraction (EBSD) after compression tests at elevated temperatures. The basal planes of both the fine and coarse grains in the deformed samples tend to rotate from the initial orientations, perpendicular to the compression axis, to an inclination of 45 deg. The Schmid factor is used to analyse how the individual slip systems activate and how their activities evolve under various deformation conditions. After deformation, the distribution frequency of the misorientation angles shows that the low angle grain boundaries increased dramatically while the high angle grain boundaries decreased. In particular, after deformation at 723 K and 0.1 s-1, a peak around 50-60 deg. in the misorientation frequency-distribution is found, which is due to {101-bar 1} twinning. The analysis of the deformed microstructure indicates that dynamic recovery is the dominant deformation mechanism for commercial pure titanium when subjected to the investigated deformation conditions.

  7. Sunspot areas and tilt angles for solar cycles 7-10

    CERN Document Server

    Pavai, V Senthamizh; Dasi-Espuig, M; Krivova, N; Solanki, S

    2015-01-01

    Extending the knowledge about the properties of solar cycles into the past is essential for understanding the solar dynamo. This paper aims at estimating areas of sunspots observed by Schwabe in 1825-1867 and at calculating the tilt angles of sunspot groups. The sunspot sizes in Schwabe's drawings are not to scale and need to be converted into physical sunspot areas. We employed a statistical approach assuming that the area distribution of sunspots was the same in the 19th century as it was in the 20th century. Umbral areas for about 130,000 sunspots observed by Schwabe were obtained, as well as the tilt angles of sunspot groups assuming them to be bipolar. There is, of course, no polarity information in the observations. The annually averaged sunspot areas correlate reasonably with sunspot number. We derived an average tilt angle by attempting to exclude unipolar groups with a minimum separation of the two alleged polarities and an outlier rejection method which follows the evolution of each group and detect...

  8. Effects of the rotation angle on surface plasmon coupling of nanoprisms.

    Science.gov (United States)

    Chien, Miao-Hsuan; Nien, Li-Wei; Chao, Bo-Kai; Li, Jia-Han; Hsueh, Chun-Hway

    2016-02-14

    We studied the effects of relative orientation of bowtie nanostructures on the plasmon resonance both experimentally and theoretically in this work. Specifically, we fabricated gold bowtie nanoantennas with rotated nanoprisms, measured the near-field and the far-field resonance behaviors using Raman spectroscopy and scattering microspectroscopy, and simulated the effects of the rotation angle on the localized surface plasmonic resonance using finite-difference time-domain simulations. In addition to the widely-discussed dipolar resonance in regular bowtie nanostructures, defined as tip-mode resonance in the present study, the excitations of edge-mode resonance were discovered under certain rotation angles of nanoprisms. Because of the resonances of different modes at different wavelengths, two different incident laser sources were used to measure the Raman spectra to provide evidence for the evolution of different resonance modes. Also, both the tip-mode and edge-mode resonances were verified by the simulated charge density distribution and their trends were discussed. Based on the discovered trend, a plasmon protractor was created with a near-exponential decay relationship between the relative resonance wavelength shift and cosine of the rotation angle. A plasmon hybridization model was also proposed for rotated bowties to explain the coupling between nanoprisms during rotation. PMID:26809737

  9. Regional Distribution and Its Pattern Evolution of the Winter Olympics Gold Medals%冬奥会金牌区域归属与格局演变

    Institute of Scientific and Technical Information of China (English)

    刘志华

    2014-01-01

    Through the quantitative statistics and regional distribution of the 22 games' gold medals of Winter Olympics from 1924 to 2014,the paper analyzes the dynamic change and pattern evolution of various regional gold medals. It draws a conclusion that the competitive pattern shows the strong is always strong,the polarization is serious with the legible boundary between strong area and weak area,a weak one is difficult to upgrade into strong area for a long time. European and American powers represented by Russia,Germany,Norway and USA have long-term regional monopoly with balanced development. The common countries obviously show selective advantage with unbalanced development, and the weak countries have well development trend by giving priority to choose the breakthrough according to respective national conditions.The fierce competition in the strong area and the rise of some weak ones result in a dispersed trend of gold medals distribution,the difference of competitive strength in various areas is diminishing in the shift. It should be to achieve the harmonious development of winter and summer Olympics in China by project planning based on the regional characteristics according to the evolution rule of competitive pattern.%通过对1924~2014年举办过的22届冬季奥运会金牌数及区域归属进行分类统计,分析各区域金牌的动态变化及竞技格局的演变。得出结论:竞技格局呈现出强者恒强的态势,强势区域与弱势区域界限清晰,两级分化严重,长时间内会继续维持,弱势区域很难升级到强势区域。以俄罗斯、德国、挪威、美国为代表的欧美强势国形成长期性区域垄断,项目发展相对均衡;较强国家项目发展不均衡,存在明显的选择性优势;弱势国家根据各自的国情,有重点地选择性突破,形成了良好的发展态势。强势区域的激烈竞争,弱势区域的突破崛起,导致金牌分布趋于分散,各区域的竞

  10. Calculation of Triggering Angle of Thyristor Rectifiers with Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Fahri VATANSEVER

    2015-05-01

    Full Text Available Rectifier circuits have important role in electrical energy systems. Especially in thyristor rectifiers which have capability of generating multiple voltage level, determining/calculating the optimal trigger angle and applying trigger signal at this angles are among the main process. In this study, desired level of average output voltage according to trigger angles is obtained both classically (mathematically solving of equations and using evolutionary algorithms which are genetic algorithms and differential evolutions. In this way, a software can be used in educational purposes which can calculate optimal trigger angles using both mathematically and heuristically, show results and many properties/parameters of circuit graphically and numerically is developed. Analysis/simulations performed with the designed software indicates that evolutionary algorithms can be used in this field effectively and efficiently.

  11. Research on Commercial Center Evolution and Distribution in Nanjing%南京商业中心演化与布局研究

    Institute of Scientific and Technical Information of China (English)

    牟宇峰; 孙伟; 吴加伟

    2014-01-01

    随着时代的发展,城市商业活动的频率和强度明显增多和增强,商业中心的作用越来越重要。商业中心的合理布局不仅可以满足消费需求、促进商业中心繁荣,而且会影响城市空间结构和居住区、商业区等的功能布局。为此,本文以南京为研究区域,总结商业发展的现状特征,研究城市商业中心体系的演变过程,分析影响商业中心形成与分布的因素。在此基础之上,通过圈层距离法和可达性方法,评价南京商业中心布局的合理性,并提出优化空间布局的方案。研究发现南京商业中心的分布具有时代特点,在20多年的发展过程中,其规模和等级结构均发生变化。其次,目前南京商业中心布局不合理,中心城区密度过大,郊区数量不足;要通过合理规划和增强交通可达性等方法加以解决。%City functioned as production, resident and administration and market based on commercial activities together form the modern city. With the development of time, the frequency and intensity of urban commercial activities increase and enhance significantly, and then the role of commercial center is more important increasingly. The reasonable layout of the business centre can not only satisfy the consumer demand and promote the business center prosperity, but also affect the city space structure and the function layout of residential and commercial districts. So the article sums up the current characteristics of the commercial development, studies the evolution process of urban commercial center system and analyses influencing factors of formation and distribution of commercial center based on minimum statistical unit for grid by the method of sphere distance and accessibility in Nanjing. Then on this basis by the methods of circle distance and accessibility, the paper evaluates the rationality of commercial center distribution in Nanjing and puts forward the program

  12. Weak mixing angle measurements at hadron colliders

    CERN Document Server

    Di Simone, Andrea; The ATLAS collaboration

    2015-01-01

    The Talk will cover weak mixing angle measurements at hadron colliders ATLAS and CMS in particular. ATLAS has measured the forward-backward asymmetry for the neutral current Drell Yan process in a wide mass range around the Z resonance region using dielectron and dimuon final states with $\\sqrt{s}$ =7 TeV data. For the dielectron channel, the measurement includes electrons detected in the forward calorimeter which extends the covered phase space. The result is then used to extract a measurement of the effective weak mixing angle. Uncertainties from the limited knowledge on the parton distribution functions in the proton constitute a significant part of the uncertainty and a dedicated study is performed to obtain a PDF set describing W and Z data measured previously by ATLAS. Similar studies from CMS will be reported.

  13. Measurement of the azimuthal angle distribution of leptons from W boson decays as a function of the W transverse momentum in p anti-p collisions at s**(1/2) = 1.8-TeV

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, D.; Affolder, Anthony A.; Albrow, M.G.; Ambrose, D.; Amidei, D.; Anikeev, K.; Antos, J.; Apollinari, G.; Arisawa, T.; Artikov, A.; Ashmanskas, W.; Azfar, F.; Azzi-Bacchetta, P.; Bacchetta, N.; Bachacou, H.; Badgett, W.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Baroiant, S.; Barone, M.; /Taiwan, Inst. Phys. /Argonne /INFN,

    2005-04-01

    We present the first measurement of the A{sub 2} and A{sub 3} angular coefficients of the W boson produced in proton-antiproton collisions. We study W {yields} ev{sub e} and W {yields} {mu}{nu}{sub {mu}} candidate events produced in association with at least one jet at CDF, during Run Ia and Run Ib of the Tevatron at {radical}s = 1.8 TeV. The corresponding integrated luminosity was 110 pb{sup -1}. The jet balances the transverse momentum of the W and introduces QCD effects in W boson production. The extraction of the angular coefficients is achieved through the direct measurement of the azimuthal angle of the charged lepton in the Collins-Soper rest-frame of the W boson. The angular coefficients are measured as a function of the transverse momentum of the W boson. The electron, muon, and combined results are in good agreement with the Standard Model prediction, up to order {alpha}{sub s}{sup 2} in QCD.

  14. Fractal dimension and unscreened angles measured for radial viscous fingering.

    Science.gov (United States)

    Praud, Olivier; Swinney, Harry L

    2005-07-01

    We have examined fractal patterns formed by the injection of air into oil in a thin (0.127 mm) layer contained between two cylindrical glass plates of 288 mm diameter (a Hele-Shaw cell), for pressure differences in the range 0.25 DLA) clusters. We have also measured the probability distribution of unscreened angles. At late times, the distribution approaches a universal (i.e., forcing and size-independent) asymptotic form that has mean 145 degrees Celsius and standard deviation 36 degrees Celsius. These results indicate that the distribution function for the unscreened angle is an invariant property of the growth process. PMID:16089960

  15. Wide-angle energy-momentum spectroscopy

    CERN Document Server

    Dodson, Christopher M; Li, Dongfang; Zia, Rashid

    2014-01-01

    Light emission is defined by its distribution in energy, momentum, and polarization. Here, we demonstrate a method that resolves these distributions by means of wide-angle energy-momentum spectroscopy. Specifically, we image the back focal plane of a microscope objective through a Wollaston prism to obtain polarized Fourier-space momentum distributions, and disperse these two-dimensional radiation patterns through an imaging spectrograph without an entrance slit. The resulting measurements represent a convolution of individual radiation patterns at adjacent wavelengths, which can be readily deconvolved using any well-defined basis for light emission. As an illustrative example, we use this technique with the multipole basis to quantify the intrinsic emission rates for electric and magnetic dipole transitions in europium-doped yttrium oxide (Eu$^{3+}$:Y$_{2}$O$_{3}$) and chromium-doped magnesium oxide (Cr$^{3+}$:MgO). Once extracted, these rates allow us to reconstruct the full, polarized, two-dimensional radi...

  16. CATV Network Evolution

    OpenAIRE

    Vladimir Hottmar; Ladislav Schwartz; Jan Hlubik

    2006-01-01

    Cable television (CATV) distributions are transmissions systems assigned for received and distribution televisions (TV) and radios (R) signals. This paragraph is about individual stages of evolution of this distribution. It begins by classic CATV network by using coaxial cable then it continues by modernization of optical fibre. It describes structure and two-way communication of interactive TV cable distribution frame and it describes intelligence of this network. By implementation ...

  17. Calculations of the Wigner angle

    International Nuclear Information System (INIS)

    Two new methods to determine Wigner's angle in special relativity are presented. The first one consists in calculating the angle between the compositions u-bar x ν-bar and ν-bar x u-bar of the two non-collinear velocities u-bar and ν-bar. In another method we introduce a generalization in the complex plane of Einstein's addition law of parallel velocities. (author)

  18. The correlation between quarter point angle and strong absorption radius

    CERN Document Server

    Ma, W H; Mukherjee, S; Wang, Q; Patel, D; Yang, Y Y; Ma, J B; Ma, P; Jin, S L; Bai, Z; Liu, X Q

    2016-01-01

    The main objective of the present work is to correlate quarter-point angle and nuclear radius or nuclear matter distribution. Various phenomenological formulae with parameters for strong absorption radius Rs are obtained and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems. The parameterized formula of Rs related to the isospin and binding energy is recommended, that gives a good reproduction of nuclear matter radii of halo nuclei.

  19. A study of images of Projective Angles of pulmonary veins

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jue [Beijing Anzhen Hospital, Beijing (China); Zhaoqi, Zhang [Beijing Anzhen Hospital, Beijing (China)], E-mail: zhaoqi5000@vip.sohu.com; Yu Wei; Miao Cuilian; Yan Zixu; Zhao Yike [Beijing Anzhen Hospital, Beijing (China)

    2009-09-15

    Aims: In images of magnetic resonance and computed tomography (CT) there are visible angles between pulmonary veins and the coronary, transversal or sagittal section of body. In this study these angles are measured and defined as Projective Angles of pulmonary veins. Several possible influential factors and characters of distribution are studied and analyzed for a better understanding of this imaging anatomic character of pulmonary veins. And it could be the anatomic base of adjusting correctly the angle of the central X-ray of the angiography of pulmonary veins undergoing the catheter ablation of atrial fibrillation (AF). Method: Images of contrast enhanced magnetic resonance angiography (CEMRA) and contrast enhanced computer tomography (CECT) of the left atrium and pulmonary veins of 137 health objects and patients with atrial fibrillation (AF) are processed with the technique of post-processing, and Projective Angles to the coronary and transversal sections are measured and analyzed statistically. Result: Project Angles of pulmonary veins are one of real and steady imaging anatomic characteristics of pulmonary veins. The statistical distribution of variables is relatively concentrated, with a fairly good representation of average value. It is possible to improve the angle of the central X-ray according to the average value in the selective angiography of pulmonary veins undergoing the catheter ablation of AF.

  20. Precise predictions of neutrino mixing angles and $CP$ phase

    CERN Document Server

    Abbas, Gauhar

    2016-01-01

    The neutrino mixing parameters are studied using renormalization-group evolution of Dirac neutrinos with recently proposed parameterization of the neutrino mixing angles referred as `high-scale mixing relations'. The correlations among all neutrino mixing and $CP$ violating parameters are investigated. The predictions for the neutrino mixing angles and the $CP$ phase are precise and could be easily tested by ongoing and future experiments. We observe that the high scale mixing unification hypothesis is incompatible with Dirac neutrinos due to updated experimental data.

  1. Microstructural evolution in recrystallized and unrecrystallized Al–Mg–Sc alloys during superplastic deformation

    International Nuclear Information System (INIS)

    Highlights: ► Microstructural evolution of extruded Al–Mg–Sc was divided into three stages. ► Subgrain rotation and coalescence occurred in early strain hardening stage. ► Dynamic recrystallization in the middle stage resulted in strain softening. ► Grain boundary sliding and dynamic grain growth occurred in final deformation stage. ► Friction stir processed alloy remained a random grain distribution at various strains. - Abstract: The microstructural evolution of unrecrystallized (extruded) and recrystallized (friction stir processed, FSP) Al–Mg–Sc alloys during superplastic straining was investigated using electron backscatter diffraction (EBSD). The unrecrystallized structure gradually transformed into a recrystallized structure, characterized by equiaxed grains, random boundary misorientation distribution and a weak texture at high strains. This evolution was divided into three stages based on true stress–strain curves and EBSD maps, i.e. subgrain rotation and coalescence in the early stage, dynamic recrystallization in the middle stage, and grain boundary sliding (GBS) and dynamic grain growth in the final stage. By comparison, the recrystallized grains in the FSP Al–Mg–Sc maintained a random distribution during the whole deformation process, however the grain size increased significantly with increasing strain, indicating that the main deformation mechanism was always GBS and dynamic grain growth. A deformation model was proposed to explain the microstructural evolution during superplastic deformation. The microstructure with the random boundary misorientations reaches a dynamic balance because the transformation between high-angle grain boundaries and low-angle grain boundaries is equivalent.

  2. Characterisation of creep cavitation damage in a stainless steel pressure vessel using small angle neutron scattering

    CERN Document Server

    Bouchard, P J; Treimer, W

    2002-01-01

    Grain-boundary cavitation is the dominant failure mode associated with initiation of reheat cracking, which has been widely observed in austenitic stainless steel pressure vessels operating at temperatures within the creep range (>450 C). Small angle neutron scattering (SANS) experiments at the LLB PAXE instrument (Saclay) and the V12 double-crystal diffractometer of the HMI-BENSC facility (Berlin) are used to characterise cavitation damage (in the size range R=10-2000 nm) in a variety of creep specimens extracted from ex-service plant. Factors that affect the evolution of cavities and the cavity-size distribution are discussed. The results demonstrate that SANS techniques have the potential to quantify the development of creep damage in type-316H stainless steel, and thereby link microstructural damage with ductility-exhaustion models of reheat cracking. (orig.)

  3. Structural effects of three-dimensional angle-interlock woven composite undergoing bending cyclic loading

    Science.gov (United States)

    Jin, LiMin; Yao, Yao; Yu, YiMin; Rotich, Gideon; Sun, BaoZhong; Gu, BoHong

    2014-03-01

    This paper reports the structural effects of three-dimensional (3-D) angle-interlock woven composite (3DAWC) undergoing three-point bending cyclic loading from experimental and finite element analysis (FEA) approaches. In experiment, the fatigue tests were conducted to measure the bending deflection and to observe the damage morphologies. By the FEA approach, a micro-structural unit-cell model of the 3DAWC was established at the yarn level to simulate the fatigue damage. The stress degradation at the loading condition of constant deformation amplitude was calculated to show the degradation of mechanical properties. In addition, the stress distribution, fatigue damage evolution and critical damage regions were also obtained to qualitatively reveal the structural effects and damage mechanisms of the 3DAWC subjected to three-point bending cyclic loading.

  4. Has Human Evolution Stopped?

    Directory of Open Access Journals (Sweden)

    Alan R. Templeton

    2010-07-01

    Full Text Available It has been argued that human evolution has stopped because humans now adapt to their environment via cultural evolution and not biological evolution. However, all organisms adapt to their environment, and humans are no exception. Culture defines much of the human environment, so cultural evolution has actually led to adaptive evolution in humans. Examples are given to illustrate the rapid pace of adaptive evolution in response to cultural innovations. These adaptive responses have important implications for infectious diseases, Mendelian genetic diseases, and systemic diseases in current human populations. Moreover, evolution proceeds by mechanisms other than natural selection. The recent growth in human population size has greatly increased the reservoir of mutational variants in the human gene pool, thereby enhancing the potential for human evolution. The increase in human population size coupled with our increased capacity to move across the globe has induced a rapid and ongoing evolutionary shift in how genetic variation is distributed within and among local human populations. In particular, genetic differences between human populations are rapidly diminishing and individual heterozygosity is increasing, with beneficial health effects. Finally, even when cultural evolution eliminates selection on a trait, the trait can still evolve due to natural selection on other traits. Our traits are not isolated, independent units, but rather are integrated into a functional whole, so selection on one trait can cause evolution to occur on another trait, sometimes with mildly maladaptive consequences.

  5. Frequency scaling for angle gathers

    KAUST Repository

    Zuberi, M. A H

    2014-01-01

    Angle gathers provide an extra dimension to analyze the velocity after migration. Space-shift and time shift-imaging conditions are two methods used to obtain angle gathers, but both are reasonably expensive. By scaling the time-lag axis of the time-shifted images, the computational cost of the time shift imaging condition can be considerably reduced. In imaging and more so Full waveform inversion, frequencydomain Helmholtz solvers are used more often to solve for the wavefields than conventional time domain extrapolators. In such cases, we do not need to extend the image, instead we scale the frequency axis of the frequency domain image to obtain the angle gathers more efficiently. Application on synthetic data demonstrate such features.

  6. Off-Angle Iris Correction using a Biological Model

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Joseph T [ORNL; Santos-Villalobos, Hector J [ORNL; Karakaya, Mahmut [ORNL; Barstow, Del R [ORNL; Bolme, David S [ORNL; Boehnen, Chris Bensing [ORNL

    2013-01-01

    This work implements an eye model to simulate corneal refraction effects. Using this model, ray tracing is performed to calculate transforms to remove refractive effects in off-angle iris images when reprojected to a frontal view. The correction process is used as a preprocessing step for off-angle iris images for input to a commercial matcher. With this method, a match score distribution mean improvement of 11.65% for 30 degree images, 44.94% for 40 degree images, and 146.1% improvement for 50 degree images is observed versus match score distributions with unmodi ed images.

  7. Edge effects in angle-ply composite laminates

    Science.gov (United States)

    Hsu, P. W.; Herakovich, C. T.

    1977-01-01

    This paper presents the results of a zeroth-order solution for edge effects in angle-ply composite laminates obtained using perturbation techniques and a limiting free body approach. The general solution for edge effects in laminates of arbitrary angle ply is applied to the special case of a (+ or - 45)s graphite/epoxy laminate. Interlaminar stress distributions are obtained as a function of the laminate thickness-to-width ratio and compared to finite difference results. The solution predicts stable, continuous stress distributions, determines finite maximum tensile interlaminar normal stress and provides mathematical evidence for singular interlaminar shear stresses in (+ or - 45) graphite/epoxy laminates.

  8. Transition from in-plane to out-of-plane azimuthal enhancement in Au+Au collisions 25.75.Ld; 25.70.Pq; Nuclear reactions; E=90-400A MeV; Semicentral collisions; Flow angle; Azimuthal distributions; Transition energy; Quantum molecular dynamics model; Nuclear matter Equation of State

    CERN Document Server

    Andronic, A; Petrovici, M; Simion, V; Crochet, Philippe; Alard, J P; Averbeck, R; Barret, V; Basrak, Z; Bastid, N; Bendarag, A; Berek, G; Caplar, R; Devismes, A; Dupieux, P; Dzelalija, M; Eskef, M; Finck, C; Fodor, Z; Gobbi, A; Grishkin, Y; Hartmann, O N; Herrmann, N; Hildenbrand, K D; Hong, B; Kecskeméti, J; Kim, Y J; Kirejczyk, M; Korolija, M; Kotte, R; Kress, T; Kutsche, R; Lebedev, A; Lee, K S; Leifels, Y; Man'ko, V; Merlitz, H; Neubert, W; Pelte, D; Plettner, C; Rami, F; Reisdorf, W; De Schauenburg, B; Schuell, D; Seres, Z; Sikora, B; Sim, K S; Siwek-Wilczynska, K; Smolyankin, V T; Stockmeier, M R; Vasilev, M; Wagner, P; Wisniewski, K; Wohlfarth, D; Yushmanov, I E; Zhilin, A

    2001-01-01

    The incident energy at which the azimuthal distributions in semicentral heavy-ion collisions change from in-plane to out-of-plane enhancement -- E sub t sub r sub a sub n is studied as a function of mass of emitted particles, their transverse momentum and centrality for Au+Au collisions. The analysis is performed in a reference frame rotated with the sidewards flow angle (THETA sub f sub l sub o sub w) relative to the beam axis. A systematic decrease of E sub t sub r sub a sub n as function of mass of the reaction products, their transverse momentum and collision centrality is evidenced. The predictions of a microscopic transport model (IQMD) are compared with the experimental results.

  9. Fission Fragment Folding Angle Distributions for the Systems sup 1 sup 1 B+ sup 2 sup 3 sup 7 Np, sup 1 sup 2 C+ sup 2 sup 3 sup 6 U, and sup 1 sup 6 O+ sup 2 sup 3 sup 2 Th in the Energy Range 1.1

    CERN Document Server

    Kailas, S; Chatterjee, A; Saxena, A; Kapoor, S S; Vandenbosch, R; Lestone, J P; Liang, J F; Prindle, D J; Sonzogni, A A; Bierman, J D

    1999-01-01

    Fission fragment folding angle distributions have been measured for the systems sup 1 sup 1 B+ sup 2 sup 3 sup 7 Np, sup 1 sup 2 C+ sup 2 sup 3 sup 6 U, and sup 1 sup 6 O+ sup 2 sup 3 sup 2 Th, populating the same compound nucleus ( sup 2 sup 4 sup 8 Cf) and at similar excitation energies (E sub x 45-100 MeV). The full momentum transfer and incomplete momentum transfer fusion-fission components have been separated over the bombarding energy range 1.1T) and with smaller fission barriers (B sub f >T). It was interesting to find that the effective moment of inertia (J sub e sub f sub f) values deduced from the latter component were consistent with the values from Sierk prescription used in the former case

  10. Systematic variations in divergence angle

    CERN Document Server

    Okabe, Takuya

    2012-01-01

    Practical methods for quantitative analysis of radial and angular coordinates of leafy organs of vascular plants are presented and applied to published phyllotactic patterns of various real systems from young leaves on a shoot tip to florets on a flower head. The constancy of divergence angle is borne out with accuracy of less than a degree. It is shown that apparent fluctuations in divergence angle are in large part systematic variations caused by the invalid assumption of a fixed center and/or by secondary deformations, while random fluctuations are of minor importance.

  11. A Wide-Angle Seismic Experiment in the Skagerrak

    OpenAIRE

    2000-01-01

    From May 21-27, 1999, a wide-angle seismic experiment was carried out in the Skagerrak Graben. The experiment was a combined effort of the department of Geology, University of Oslo and Geomar, Kiel (as partners in the EU-TMR project: Permo-Carboniferous Rifting in Europe (PCR) - Magmatism, Geodynamics and Thermal Evolution of the Lithosphere), the Geological Institute, University of Copenhagen (Denmark) and the Geophysical Institute, University of Hamburg (Germany). The involvement of the Uni...

  12. Relação entre o ângulo quadriciptal (ÂQ e a distribuição da pressão plantar em jogadores de futebol Relationship between quadriceps angle (Q and plantar pressure distribution in football players

    Directory of Open Access Journals (Sweden)

    Rafael G. Braz

    2010-08-01

    Full Text Available OBJETIVOS: Verificar possível associação entre ângulo quadriciptal (ÂQ e distribuição de pressão plantar em jogadores de futebol, comparando-os com indivíduos não praticantes da modalidade. MÉTODOS: Cento e vinte e um participantes do sexo masculino foram selecionados: 50 jogadores de futebol (JF e 71 sujeitos para o grupo controle (GC. Avaliaram-se concomitantemente o ÂQ, por meio do Software para Avaliação Postural (SAPO, e a pressão plantar, pela plataforma F-Scan/F-Mat System. Para verificar correlação entre o ÂQ e os valores de picos de pressão em quatro segmentos do pé (antepé medial e lateral, médio-pé e retropé, utilizou-se o Coeficiente de Pearson (r para análises paramétricas. O teste t independente foi empregado para comparar isoladamente essas mesmas variáveis entre os grupos. A normalidade dos dados foi verificada pelos valores de skewness, adotando nível de significância de 5%. RESULTADOS: Encontrou-se correlação negativa e fraca (r=-0,32 somente entre ÂQ e médio-pé direito. Os grupos diferiram quanto ao ÂQ bilateralmente, sendo que o grupo JF teve média de 11,36º, e GC, de 13,80º à direita e de 11,03º contra 13,96º à esquerda, respectivamente. Em relação à pressão plantar, o JF teve maior média de força nas faces laterais do antepé direito (0,77 contra 0,63 kg/cm² e esquerdo (0,65 e 0,54 kg/cm², enquanto o GC apresentou maior pico de pressão no médio-pé esquerdo (JF: 0,37 e GC: 0,46 kg/cm². CONCLUSÕES: Não houve relação entre os valores de ÂQ na distribuição da pressão plantar nos jogadores de futebol. Os atletas apresentaram, porém, ÂQ diminuído e maiores picos de pressão nas faces laterais de ambos os pés, o que sugere alinhamento em varo dos joelhos e distribuição supinada das bases plantares.OBJECTIVES: To determine whether there is an association between the Q-angle (Q and the distribution of plantar pressure in football players, and to compare the

  13. Dynamics of secular evolution

    CERN Document Server

    Binney, James

    2012-01-01

    The text of lectures to the 2011 Tenerife Winter School. The School's theme was "Secular Evolution of Galaxies" and my task was to present the underlying stellar-dynamical theory. Other lecturers were speaking on the role of bars and chemical evolution, so these topics are avoided here. We start with an account of the connections between isolating integrals, quasiperiodicity and angle-action variables - these variables played a unifying role throughout the lectures. This leads on to the phenomenon of resonant trapping and how this can lead to chaos in cuspy potentials and phase-space mixing in slowly evolving potentials. Surfaces of section and frequency analysis are introduced as diagnostics of phase-space structure. Real galactic potentials include a fluctuating part that drives the system towards unattainable thermal equilibrium. Two-body encounters are only one source of fluctuations, and all fluctuations will drive similar evolution. We derive the orbit-averaged Fokker-Planck equation and relations that ...

  14. Discovering the Inscribed Angle Theorem

    Science.gov (United States)

    Roscoe, Matt B.

    2012-01-01

    Learning to play tennis is difficult. It takes practice, but it also helps to have a coach--someone who gives tips and pointers but allows the freedom to play the game on one's own. Learning to act like a mathematician is a similar process. Students report that the process of proving the inscribed angle theorem is challenging and, at times,…

  15. Contactless angle detection using permalloy

    NARCIS (Netherlands)

    Eijkel, Kees J.; Rijk, Rolf

    1988-01-01

    An overview is given of measurements on angle detectors. The detectors consist of a pair of planar-Hall elements opposite to a rotatable magnet. The measurements are performed on a number of planar-Hall elements of different shape and size, and show good agreement with a previously described theoret

  16. CATV Network Evolution

    Directory of Open Access Journals (Sweden)

    Jan Hlubik

    2006-01-01

    Full Text Available Cable television (CATV distributions are transmissions systems assigned for received and distribution televisions(TV and radios (R signals. This paragraph is about individual stages of evolution of this distribution. It begins by classic CATVnetwork by using coaxial cable then it continues by modernization of optical fibre. It describes structure and two-waycommunication of interactive TV cable distribution frame and it describes intelligence of this network. By implementationinteractivity we can not understand it as the CATV network as only distributions system which transfers only TV and R signalsbut like multifunctional system which can transfer information by both directions.

  17. The evolution of streams in a time-dependent potential

    CERN Document Server

    Buist, Hans J T

    2015-01-01

    We study the evolution of streams in a time-dependent spherical gravitational potential. Our goal is to establish what are the imprints of this time evolution on the properties of streams as well as their observability. To this end, we have performed a suite of numerical experiments for a host system that doubles its mass during the integration time and for a variety of initial conditions. In these experiments we found that the most striking imprint is a misalignment of 10 degrees in the angular location of the apocentres of the streams compared to the static case (and to the orbit of the centre of mass), which only becomes apparent for sufficiently long streams. We have also developed an analytic model using action-angle variables which allows us to explain this behaviour and to identify the most important signature of time evolution, namely a difference in the slope defined by the distribution of particles along a stream in frequency and in angle space. Although a difference in slope can arise when the pres...

  18. Pressure coefficient evolutions on the blades of a Savonius rotor

    Energy Technology Data Exchange (ETDEWEB)

    Chauvin, A.; Guignard, S. [UMRR 7343, Marseilles (France). Lab. IUSTI; Kamoun, B. [Faculte des Sciences de Sfax (Tunisia). Lab. de Physique

    2012-07-01

    Measurements of the pressure field distribution on the blades of a vertical axis Savonius wind machine are presented. The rotor used in the wind tunnel is a two blades cylindrical shape with a central gap. Pressure gauges are placed on each side of a blade, so the pressure jumps between intrados and extrados of a blade during a whole rotation are drawn. In the static configuration, the machine is disposed at various incidences. The determination of pressure jumps allows to calculate the static torque of the machine versus the incidence angle. In the dynamic situation the machine is rotating at various frequencies and gauges signals are varying dynamically of course with the incidence. The dynamic torque coefficient is calculated. Evolutions of the starting torque and starting conditions are then described and dynamic effects on torque evolution are presented. (orig.)

  19. Evolution of alanine:glyoxylate aminotransferase 1 peroxisomal and mitochondrial targeting. A survey of its subcellular distribution in the livers of various representatives of the classes Mammalia, Aves and Amphibia.

    Science.gov (United States)

    Danpure, C J; Fryer, P; Jennings, P R; Allsop, J; Griffiths, S; Cunningham, A

    1994-08-01

    As part of a wider study on the molecular evolution of alanine:glyoxylate aminotransferase 1 (AGT1) intracellular compartmentalization, we have determined the subcellular distribution of immunoreactive AGT1, using postembedding protein A-gold immunoelectron microscopy, in the livers of various members of the classes Mammalia, Aves, and Amphibia. As far as organellar distribution is concerned, three categories could be distinguished. In members of the first category (type I), all, or nearly all, of the immunoreactive AGT1 was concentrated within the peroxisomes. In the second category (type II), AGT1 was found more evenly distributed in both peroxisomes and mitochondria. In the third category (type III), AGT1 was localized mainly within the mitochondria with much lower, but widely variable, amounts in the peroxisomes. Type I animals include the human, two great apes (gorilla, orangutan), two Old World monkeys (anubis baboon, Japanese macaque), a New World monkey (white-faced Saki monkey), a lago, morph (European rabbit), a bat (Seba's short-tailed fruit bat), two caviomorph rodents (guinea pig, orange-rumped agouti), and two Australian marsupials (koala, Bennett's wallaby). Type II animals include two New World monkeys (common marmoset, cotton-top tamarin), three prosimians (brown lemur, fat-tailed dwarf lemur, pygmy slow loris), five rodents (a hybrid crested porcupine, Colombian ground squirrel, laboratory rat, laboratory mouse, golden hamster), an American marsupial (grey short-tailed opossum), and a bird (raven). Type III animals include the large tree shrew, three insectivores (common Eurasian mole, European hedgehog, house shrew), four carnivores (domestic cat, ocelot, domestic dog, polecat ferret), and an amphibian (common frog). In addition to these categories, some animals (e.g. guinea pig, common frog) possessed significant amounts of cytosolic AGT1. Whereas the subcellular distribution of AGT1 in some orders (e.g. Insectivora and Carnivora) did not appear

  20. Evolution of wettability in terms of petroleum and petroleum fractions adsorption. An approach by the Wilhelmy method; Evolution de la mouillabilite en fonction de l`adsorption du petrole et de ses fractions. Approche par la methode des angles de contact dynamiques

    Energy Technology Data Exchange (ETDEWEB)

    Mattos Saliba, A.

    1996-12-06

    Reservoir wettability is very important to petroleum recovery by waterflooding and other processes. It is a key parameter controlling multiphase flow and fluids distribution in a porous medium. Nevertheless, the original water-wetness can be modified by the petroleum`s natural surfactants (asphaltenes and resins) adsorption onto the rock surface. This adsorption may reduce petroleum recovery. In this study, the adsorption of model molecules (pyridine and benzo-quinoline), of rude oil and of its heavier fractions (asphaltenes and resins) has been investigated in terms of wettability alteration for initially water-wet surfaces (glass or quartz). In this case, the dynamic Wilhelmy plate technique provides quantitative values of wetting preference to either oil or water. The results show that, at ambient conditions, adsorption depends on concentration, adsorbent/adsorbate interaction time, pH, solvent type, substrate surface, brine concentration and environment liquid phase (water or oil). However, the initial water film on the surface does not strongly influence this phenomena. (author) 222 refs.

  1. Modeling human-water-systems: towards a comprehensive and spatially distributed assessment of co-evolutions for river basins in Central Europe

    OpenAIRE

    Krahe, Peter; Nilson, Enno; Knoche, Malte; Ebner von Eschenbach, Anna-Dorothea

    2016-01-01

    In the context of river basin and flood risk management there is a growing need to improve the understanding of and the feedbacks between the driving forces “climate and socio-economy” and water systems. We make use of a variety of data resources to illustrate interrelationships between different constituents of the human-water-systems. Taking water storage for energy production as an example we present a first analysis on the co-evolution of socio-economic and hydrological ...

  2. Active probing of cloud thickness and optical depth using wide-angle imaging LIDAR

    International Nuclear Information System (INIS)

    At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60o full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Section 2 covers the up-to-date evolution of the nighttime WAIL instrument at LANL. Section 3 reports our progress towards daytime capability for WAIL, an important extension to full diurnal cycle monitoring by means of an ultra-narrow magneto-optic atomic line filter. Section 4 describes briefly how the important cloud properties can be inferred from WAIL signals.

  3. Epidemiological characterization of primary open-angle glaucoma

    Directory of Open Access Journals (Sweden)

    Leonor Rosario Díaz Alfonso

    2010-11-01

    Full Text Available Background: The primary open-angle glaucoma is a problem for public health all over the world. It is a silent and slowly progressive disease leading to blindness. In most patients this can be prevented if the risk factors leading to the disease are detected in time. Objective: To describe some epidemiological factors of patients with primary open-angle glaucoma. Methods: Clinical, epidemiological, prospective and longitudinal study in patients with primary open-angle glaucoma who attended the glaucoma consultation of the Provincial General University Hospital "Dr. Gustavo Aldereguía Lima" of Cienfuegos, from January to February 2009. The following variables were analyzed: age, sex, family and personal medical history, toxic habits and time of diagnosis of the disease. Results: There was prevalence of primary open-angle glaucoma (87, 5% mostly in females (53, 6% and patients over 61 years old as well as in white skinned patients (52 and 62% respectively. Hypertension was the leading entity referred to as pathological personal and family antecedent (62 and 42% respectively. Glaucoma and myopia predominated as previous eye history. The most frequent toxic habits were the consumption of more than 2 cups of coffee a day (53% and smoking (32%. The largest amount of patients had more than 5 years evolution of the disease. Conclusions: Primary open-angle glaucoma occurred mainly in female patients and those with a history

  4. Wake angle for surface gravity waves on a finite depth fluid

    OpenAIRE

    Pethiyagoda, Ravindra; McCue, Scott W.; Moroney, Timothy J.

    2015-01-01

    Linear water wave theory suggests that wave patterns caused by a steadily moving disturbance are contained within a wedge whose half-angle depends on the depth-based Froude number $F_H$. For the problem of flow past an axisymmetric pressure distribution in a finite-depth channel, we report on the apparent angle of the wake, which is the angle of maximum peaks. For moderately deep channels, the dependence of the apparent wake angle on the Froude number is very different to the wedge angle, and...

  5. Overview of Neutrino Mixing Models and Their Mixing Angle Predictions

    Energy Technology Data Exchange (ETDEWEB)

    Albright, Carl H.

    2009-11-01

    An overview of neutrino-mixing models is presented with emphasis on the types of horizontal flavor and vertical family symmetries that have been invoked. Distributions for the mixing angles of many models are displayed. Ways to differentiate among the models and to narrow the list of viable models are discussed.

  6. Disorders of the cerebellopontine angle

    International Nuclear Information System (INIS)

    Disorders of the cerebellopontine angle may present by symptoms like vertigo, hearing problems, affection of the trigeminal or facial nerve. Ipsilateral ataxia and contralateral hemiparesis develop in case of a rather large tumor in this region and display an involvement of the cerebellum and/or brainstem. However, some of these typical symptoms are not recognized by the patient. Thus, in case of a suspicion of a disorder of the cerebellopontine angle the relevant functions have to be tested clinically. In addition, electrophysiology can confirm dysfunction of these cranial nerves. Mainstay of the therapy should be the treatment of the underlying cause. Nevertheless, not seldom it is necessary to treat symptoms like vertigo or facial pain. (orig.)

  7. Multi-angle compound imaging

    DEFF Research Database (Denmark)

    Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Sillesen, Henrik

    1998-01-01

    This paper reports on a scanning technique, denoted multi-angle compound imaging (MACI), using spatial compounding. The MACI method also contains elements of frequency compounding, as the transmit frequency is lowered for the highest beam angles in order to reduce grating lobes. Compared to...... conventional B-mode imaging MACI offers better defined tissue boundaries and lower variance of the speckle pattern, resulting in an image with reduced random variations. Design and implementation of a compound imaging system is described, images of rubber tubes and porcine aorta are shown and effects on...... visualization are discussed. The speckle reduction is analyzed numerically and the results are found to be in excellent agreement with existing theory. An investigation of detectability of low-contrast lesions shows significant improvements compared to conventional imaging. Finally, possibilities for improving...

  8. Wide-angle electron detector

    International Nuclear Information System (INIS)

    The design, functioning, and main calibration, characteristics of a wide-angle detector, capable of recording electrons with energies >= 8 keV and insensitive to u.v. solar radiation are described. A description of the sensor (electron trap) and its electronics in the analog (DEGAFOC) and counting (DEGAFOI) modes is given. Examples of telemetry recordings, illustrating the operation of the detector are included. (Auth.)

  9. Definition of resulting angle of the deviation after the passage of neutrons through the crystal

    International Nuclear Information System (INIS)

    The present paper is dedicated to the consideration of passage of neutrons in the crystal. The expression for intensity distribution is obtained by the method of the multiple scattering theories. The received results are applied to calculation angle of the deviation of neutrons by nucleus of the crystal. Here is shown that at the large angle of deviation, the intensity of distribution decreases with reduction of angle much more slowly than till Gaussian law. The received expression for the angle of the dviation allows defining of the impulse of the neutron

  10. Overview of TMD Evolution

    Science.gov (United States)

    Boer, Daniël

    2016-02-01

    Transverse momentum dependent parton distributions (TMDs) appear in many scattering processes at high energy, from the semi-inclusive DIS experiments at a few GeV to the Higgs transverse momentum distribution at the LHC. Predictions for TMD observables crucially depend on TMD factorization, which in turn determines the TMD evolution of the observables with energy. In this contribution to SPIN2014 TMD factorization is outlined, including a discussion of the treatment of the nonperturbative region, followed by a summary of results on TMD evolution, mostly applied to azimuthal asymmetries.

  11. Overview of TMD evolution

    CERN Document Server

    Boer, Daniel

    2015-01-01

    Transverse momentum dependent parton distributions (TMDs) appear in many scattering processes at high energy, from the semi-inclusive DIS experiments at a few GeV to the Higgs transverse momentum distribution at the LHC. Predictions for TMD observables crucially depend on TMD factorization, which in turn determines the TMD evolution of the observables with energy. In this contribution to SPIN2014 TMD factorization is outlined, including a discussion of the treatment of the nonperturbative region, followed by a summary of results on TMD evolution, mostly applied to azimuthal asymmetries.

  12. Effects of Different Blade Angle Distributions on Centrifugal Compressor Performance

    Directory of Open Access Journals (Sweden)

    Jari Backman

    2009-01-01

    Full Text Available A centrifugal compressor with three different shrouded 2D impellers is studied numerically. All impellers have the same dimensions, and they only differ in channel length and geometry. Noticeable differences in efficiency are observed. Two different turbulence models, Chien's k-ε and k-ω SST, are compared. For this case, k-ω SST was found more realistic. The hypothesis that pressure losses in a curved duct and in an impeller passage behave similarly is suggested and found inadequate.

  13. Effects of Different Blade Angle Distributions on Centrifugal Compressor Performance

    OpenAIRE

    Pekka Röyttä; Aki Grönman; Ahti Jaatinen; Teemu Turunen-Saaresti; Jari Backman

    2009-01-01

    A centrifugal compressor with three different shrouded 2D impellers is studied numerically. All impellers have the same dimensions, and they only differ in channel length and geometry. Noticeable differences in efficiency are observed. Two different turbulence models, Chien's k-ε and k-ω SST, are compared. For this case, k-ω SST was found more realistic. The hypothesis that pressure losses in a curved duct and in an impeller passage behave similarly is suggested and found inadequate.

  14. Riding the Elephants: The Evolution of World Economic Growth and Income Distribution at the End of the Twentieth Century (1980-2000)

    OpenAIRE

    Albert Berry; John Serieux

    2006-01-01

    This paper presents estimates of world economic growth for 1970-2000, and changes in the intercountry and interpersonal distribution of world income between 1980 and 2000. These estimates suggest that, while the rate of growth of the world economy slowed in the 1980-2000 period, and average within-country inequality worsened, the distribution of world income among individuals, nevertheless, improved a little. However, that result was wholly due to the exceptional economic performances of Chin...

  15. The distribution and copy number of copia-like retrotransposons in rice (Oryza sativa L.) and their implications in the organization and evolution of the rice genome

    OpenAIRE

    Wang, Shiping; Liu, Nan; Peng, Kaiman; Zhang, Qifa

    1999-01-01

    We used 22 fragments corresponding to the reverse transcriptase domain of copia-like retrotransposons as representatives to study the organization and distribution of these elements in the rice genome. The loci detected by these 22 fragments were assigned to 47 locations in the molecular-linkage map involving all 12 chromosomes. The distributional features of copia-like retrotransposons found in the rice genome indicated that (i) the loci detected were located mainly in one arm of each chromo...

  16. Angle-resolved cathodoluminescence imaging polarimetry

    CERN Document Server

    Osorio, Clara I; Brenny, Benjamin; Polman, Albert; Koenderink, A Femius

    2015-01-01

    Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the polarization was not fully determined. Here we demonstrate a technique to access the full polarization state of the cathodoluminescence emission, that is the Stokes parameters as a function of the emission angle. Using this technique, we measure the emission of metallic bullseye nanostructures and show that the handedness of the structure as well as nanoscale changes in excitation position induce large changes in polarization ellipticity and helicity. Furthermore, by exploiting the ability of polarimetry to distinguish polarized from unpolarized light, we quantify the contributions of different types of coherent and incoherent radiation to the emission of a gold surface, silicon and gallium arsenide bulk semiconductor...

  17. Jet opening angles and gamma-ray brightness of AGN

    CERN Document Server

    Pushkarev, A B; Lister, M L; Savolainen, T

    2009-01-01

    We have investigated the differences in apparent opening angles between the parsec-scale jets of the active galactic nuclei (AGN) detected by the Fermi Large Area Telescope (LAT) during its first three months of operations and those of non-LAT-detected AGN. We used 15.4 GHz VLBA observations of sources from the 2 cm VLBA MOJAVE program, a subset of which comprise the statistically complete flux density limited MOJAVE sample. We determined the apparent opening angles by analyzing transverse jet profiles from the data in the image plane and by applying a model fitting technique to the data in the (u,v) plane. Both methods provided comparable opening angle estimates. The apparent opening angles of gamma-ray bright blazars are preferentially larger than those of gamma-ray weak sources. At the same time, we have found the two groups to have similar intrinsic opening angle distributions. This suggests that the jets in gamma-ray bright AGN are oriented at preferentially smaller angles to the line of sight resulting ...

  18. Q2 evolution of parton distributions at small values of x: Effective scale for combined H1 and ZEUS data on the structure function F2

    International Nuclear Information System (INIS)

    An expression for the structure function F2 in the form of Bessel functions at small values of the Bjorken variable x is used. This expression was derived for a flat initial condition in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations. The argument of the strong coupling constant was chosen in such a way as to annihilate the singular part of the anomalous dimensions in the next-to-leading-order of perturbation theory. This choice, together with the frozen and analytic versions of the strong coupling constant, is used to analyze combined data of the H1 and ZEUS Collaborations obtained recently for the structure function F2

  19. Q 2 evolution of parton distributions at small values of x: Effective scale for combined H1 and ZEUS data on the structure function F 2

    Science.gov (United States)

    Kotikov, A. V.; Shaikhatdenov, B. G.

    2015-06-01

    An expression for the structure function F 2 in the form of Bessel functions at small values of the Bjorken variable x is used. This expression was derived for a flat initial condition in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations. The argument of the strong coupling constant was chosen in such a way as to annihilate the singular part of the anomalous dimensions in the next-to-leading-order of perturbation theory. This choice, together with the frozen and analytic versions of the strong coupling constant, is used to analyze combined data of the H1 and ZEUS Collaborations obtained recently for the structure function F 2.

  20. Living polymerization induced macro- and microdomain investigated by focusing ultra-small-angle neutron scattering

    International Nuclear Information System (INIS)

    By utilizing a biconcave refractive neutron lens (MgF2) 5-inch size and high resolution position sensitive area photomultiplier with scintillator (ZnS), we constructed a focusing ultra-small-angle neutron scattering (USANS) spectrometer (SANS-J-II) at research reactor JRR3, Tokai, Japan. SANS-J-II can successfully reach to qmin=0.0003 A-1, where q (=4π sin(θ)/λ) is the magnitude of scattering vector given by wavelength λ and scattering angle 2θ, and simultaneously cover conventional small-angle neutron scattering (SANS) region to q=0.004 A-1. Focusing USANS, thus realized, plays an important role to investigate the time-evolution of hierarchically ordered structures in the living radical polymerization solution, preparing poly(methyl methacylate)-block-polystyrene (PMMA-b-PS). In the reaction process to synthesize a PS block chain from the end of PMMA block chain, we found the interplay between macro- and microphase separation. SANS at q>0.001 A-1 determined time-evolving microdomain structures; as the polymerization proceeds, (1) first by order-disorder transition, a lamellar microdomain appears and (2) second by order-order transitions, the morphologies of microdomains change to PMMA cylinder and successively to PMMA sphere. USANS at q-1, exhibiting power law scattering (∼q-α) due to macrophase separation between PMMA-b-PS and PS homopolymer (appeared as by product). The exponent α varies from 4 to 2, reflecting a grain boundary of macrodomain rich-in PMMA-b-PS; when a lamellar microdomain appears. Porod law gives α=4, whereas when cylinder and sphere appear, α=2, due to inhomogeneity of the microdomain spatial distribution of the microdomains. (author)