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Sample records for age horizontal branch

  1. Characterizing stellar halo populations II: The age gradient in blue horizontal-branch stars

    CERN Document Server

    Das, Payel; Binney, James

    2016-01-01

    The distribution of Milky Way halo blue horizontal-branch (BHB) stars is examined using action-based extended distribution functions (EDFs) that describe the locations of stars in phase space, metallicity, and age. The parameters of the EDFs are fitted using stars observed in the Sloan Extension for Galactic Understanding and Exploration-II (SEGUE-II) survey that trace the phase-space kinematics and chemistry out to ~70 kpc. A maximum a posteriori probability (MAP) estimate method and a Markov Chain Monte Carlo method are applied, taking into account the selection function in positions, distance, and metallicity for the survey. The best-fit EDF declines with actions less steeply at actions characteristic of the inner halo than at the larger actions characteristic of the outer halo, and older ages are found at smaller actions than at larger actions. In real space, the radial density profile steepens smoothly from -2 at ~2 kpc to -4 in the outer halo, with an axis ratio ~0.7 throughout. There is no indication f...

  2. Characterizing stellar halo populations II: The age gradient in blue horizontal-branch stars

    Science.gov (United States)

    Das, Payel; Williams, Angus; Binney, James

    2016-08-01

    The distribution of Milky Way halo blue horizontal-branch (BHB) stars is examined using action-based extended distribution functions (EDFs) that describe the locations of stars in phase space, metallicity, and age. The parameters of the EDFs are fitted using stars observed in the Sloan Extension for Galactic Understanding and Exploration-II (SEGUE-II) survey that trace the phase-space kinematics and chemistry out to ˜70 kpc. A maximum a posteriori probability (MAP) estimate method and a Markov Chain Monte Carlo method are applied, taking into account the selection function in positions, distance, and metallicity for the survey. The best-fit EDF declines with actions less steeply at actions characteristic of the inner halo than at the larger actions characteristic of the outer halo, and older ages are found at smaller actions than at larger actions. In real space, the radial density profile steepens smoothly from -2 at ˜2 kpc to -4 in the outer halo, with an axis ratio ˜0.7 throughout. There is no indication for rotation in the BHBs, although this is highly uncertain. A moderate level of radial anisotropy is detected, with βs varying from isotropic to between ˜0.1 and ˜0.3 in the outer halo depending on latitude. The BHB data are consistent with an age gradient of -0.03 Gyr kpc-1, with some uncertainty in the distribution of the larger ages. These results are consistent with a scenario in which older, larger systems contribute to the inner halo, whilst the outer halo is primarily comprised of younger, smaller systems.

  3. Blue Horizontal Branch Stars in M92

    CERN Document Server

    Cohen, J G

    1997-01-01

    We have analyzed high dispersion and high precision spectra of 5 blue horizontal branch stars in the globular cluster M92 to establish that the projected rotational velocity for these stars ranges from 15 to 40 \\kms. This is larger than that expected based on the rotation of their main sequence progenitors, the spin down of rotation with age, and the conservation of angular momentum. Possible explanations include a rapidly rotating stellar core. An abundance analysis of these spectra of these blue HB stars in M92 yields the same results as have been obtained from the giants in this cluster. There is a hint of a trend of higher abundance as the projected surface rotational velocity increases, which could be chance and requires confirmation.

  4. On the red giant branch mass loss in 47 Tucanae: Constraints from the horizontal branch morphology

    CERN Document Server

    Salaris, Maurizio; Pietrinferni, Adriano

    2016-01-01

    We obtain stringent constraints on the actual efficiency of mass loss for red giant branch stars in the Galactic globular cluster 47 Tuc, by comparing synthetic modeling based on stellar evolution tracks with the observed distribution of stars along the horizontal branch in the colour-magnitude-diagram. We confirm that the observed, wedge-shaped distribution of the horizontal branch can be reproduced only by accounting for a range of initial He abundances --in agreement with inferences from the analysis of the main sequence-- and a red giant branch mass loss with a small dispersion. We have carefully investigated several possible sources of uncertainty that could affect the results of the horizontal branch modeling, stemming from uncertainties in both stellar model computations and the cluster properties such as heavy element abundances, reddening and age. We determine a firm lower limit of ~0.17$Mo for the mass lost by red giant branch stars, corresponding to horizontal branch stellar masses between ~0.65Mo ...

  5. Multimodal Distributions along the Horizontal Branch

    CERN Document Server

    Ferraro, F R; Pecci, F F; Dorman, B; Rood, R T; Ferraro, Francesco R.; Paltrinieri, Barbara; Pecci, Flavio Fusi; Dorman, Ben; Rood, Robert T.

    1997-01-01

    We report on HST/WFPC2 U,V and far-ultraviolet observations of two Galactic Globular Clusters (GGCs), NGC 6205 = M13 and NGC 6093 = M80. Both of these clusters have horizontal-branch (HB) tails that extend to the helium-burning main sequence, with the hottest stars reaching theoretical effective temperatures above 35,000 K. In both clusters, groups of stars are found to be separated by narrow gaps along the blue HB sequence. These gaps appear at similar locations in the color-magnitude diagrams of the two clusters. While stochastic effects may give rise to variations in the color distribution along the HB, the coincidence of gaps in different clusters effectively rules this out as the primary cause. The comparison among the clusters strongly suggests that there are separate physical processes operating during the earlier red-giant phase of evolution to produce mass loss.

  6. The Horizontal Branch of the Sculptor Dwarf galaxy

    CERN Document Server

    Salaris, Maurizio; Tolstoy, Eline; Fiorentino, Giuliana; Cassisi, Santi

    2013-01-01

    We have performed the first detailed simulation of the horizontal branch of the Sculptor dwarf spheroidal galaxy by means of synthetic modelling techniques,taking consistently into account the star formation history and metallicity evolution as determined from the main sequence and red giant branch spectroscopic observations. The only free parameter in the whole analysis is the integrated mass loss of red giant branch stars. This is the first time that synthetic horizontal branch models, consistent with the complex star formation history of a galaxy, are calculated and matched to the observations. We find that the metallicity range covered by the star formation history, as constrained by observations, plus a simple mass loss law, enable us to cover both the full magnitude and colour range of HB stars. In addition the number count distribution along the observed horizontal branch, can be also reproduced, provided that the red giant branch mass loss is mildly metallicity dependent, with a very small dispersion ...

  7. Horizontal Branch stars as AmFm/HgMn stars

    CERN Document Server

    Michaud, G

    2008-01-01

    Recent observations and models for horizontal branch stars are briefly described and compared to models for AmFm stars. The limitations of those models are emphasized by a comparison to observations and models for HgMn stars.

  8. Horizontal Branch evolution, metallicity and sdB stars

    CERN Document Server

    Michaud, G; Richard, O

    2011-01-01

    Context. Abundance anomalies have been observed in field sdB stars and in nearly all Horizontal Branch (HB) stars of globular clusters with Teff > 11 000K whatever be the cluster metallicity. Aims. The aim is to determine the abundance variations to be expected in sdB stars and in HB stars of metallicities Z \\geq 0.0001 and what observed abundances teach us about hydrodynamical processes competing with atomic diffusion. Methods. Complete stellar evolution models, including the effects of atomic diffusion and radiative acceleration, have been computed from the zero age main-sequence for metallicities of Z0 = 0.0001, 0.001, 0.004 and 0.02. On the HB the masses were selected to cover the Teff interval from 7000 to 37000K. Some 60 evolutionary HB models were calculated. The calculations of surface abundance anomalies during the horizontal branch depend on one parameter, the surface mixed mass. Results. For sdB stars with Teff 11 000K in all observed clusters, independent of metallicity, it was found that most ob...

  9. Evaporation of Jupiter like planets orbiting extreme horizontal branch stars

    OpenAIRE

    Bear, Ealeal; Soker, Noam

    2011-01-01

    We study the evaporation of planets orbiting close to hot (extreme) horizontal branch (EHB) stars. These planets survived the common envelope phase inside the envelope of the reg giant star progenitor. We find that Jupiter-like planets orbiting within 10Ro from an EHB star suffers a non-negligible mass-loss during their 10^8 yr evolution on the horizontal branch. The evaporated gas is ionized and becomes a source of Balmer lines. Such planets might be detected by the periodic variation of the...

  10. Testing the Beat Frequency Model of Horizontal Branch Qpos

    Science.gov (United States)

    Hertz, Paul

    The beat frequency modulated accretion (BFMA) model requires strong correlations in the horizontal branch quasiperiodic oscillations (HBO) and low frequency noise (LFN) amplitudes on time scales HBO and LFN amplitude predicted by the BFMA model and constrain some of the free observable parameters in the model. Any HBO model must account for these properties.

  11. Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-variable Horizontal-branch Stars. I. M3, M15, and M92

    Science.gov (United States)

    VandenBerg, Don A.; Denissenkov, P. A.; Catelan, Márcio

    2016-08-01

    Up-to-date isochrones, zero-age horizontal-branch (ZAHB) loci, and evolutionary tracks for core He-burning stars are applied to the color–magnitude diagrams of M3, M15, and M92, focusing in particular on their RR Lyrae populations. Periods for the ab- and c-type variables are calculated using the latest theoretical calibrations of {log} {P}{ab} and {log} {P}c as a function of luminosity, mass, effective temperature ({T}{{eff}}), and metallicity. Our models are generally able to reproduce the measured periods to well within the uncertainties implied by the stellar properties on which pulsation periods depend, as well as the mean periods and cluster-to-cluster differences in and , on the assumption of well-supported values of E(B-V), {(m-M)}V, and [Fe/H]. While many of RR Lyrae in M3 lie close to the same ZAHB that fits the faintest horizontal-branch (HB) stars at bluer or redder colors, the M92 variables are all significantly evolved stars from ZAHB locations on the blue side of the instability strip. M15 appears to contain a similar population of HB stars as M92, along with additional helium-enhanced populations not present in the latter which comprise most of its RR Lyrae stars. The large number of variables in M15 and the similarity of the observed values of and in M15 and M92 can be explained by HB models that allow for variations in Y. Similar ages (∼12.5 Gyr) are found for all three clusters, making them significantly younger than the field halo subgiant HD 140283. Our analysis suggests a preference for stellar models that take diffusive processes into account.

  12. Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-Variable Horizontal-Branch Stars. I. M3, M15, and M92

    CERN Document Server

    VandenBerg, Don A; Catelan, Marcio

    2016-01-01

    Up-to-date isochrones, zero-age horizontal branch (ZAHB) loci, and evolutionary tracks for core He-burning stars are applied to the color-magnitude diagrams (CMDs) of M3, M15, and M92, focusing in particular on their RR Lyrae populations. Periods for ab- and c-type variables are calculated using the latest theoretical calibrations of log P_ab and log P_c as a function of luminosity, mass, effective temperature, and metallicity. Our models are generally able to reproduce the measured periods to well within the uncertainties implied by the stellar properties on which pulsation periods depend, as well as the mean periods and cluster-to-cluster differences in and , on the assumption of well-supported values of E(B-V), (m-M)_V, and [Fe/H]. While many of the RR Lyrae in M3 lie close to the same ZAHB that fits the faintest HB stars at bluer or redder colors, the M92 variables are all significantly evolved stars from ZAHB locations on the blue side of the instability strip. M15 appears to contain a similar populatio...

  13. Horizontal branch morphology in galactic globular clusters dense environment is "a" second parameter

    CERN Document Server

    Buonanno, R; Bellazzini, M; Ferraro, F R; Pecci, F F

    1996-01-01

    The Horizontal Branch (HB) morphology in the color -- magnitude diagram of the Galactic globular clusters depends on many factors, and it is now firmly established that the so-called Second Parameter is not just the cluster age as claimed for several years. As a part of a wider program devoted to the search for the physical processes driving the Horizontal Branch Morphology, we re-address here the problem of the extension of blue HB tails by introducing a new quantitative observable, B2/B+R+V where B2={Number of HB stars with (B-V)_0<-0.02}. We demonstrate that the environmental conditions within a cluster clearly affect its HB morphology, in the sense that, in general, the higher the cluster central density the higher is the relative number of stars populating the most blue region of its HB.

  14. Inclusion of Horizontal Branch stars in the derivation of star formation histories of dwarf galaxies: the Carina dSph

    CERN Document Server

    Savino, Alessandro; Tolstoy, Eline

    2015-01-01

    We present a detailed analysis of the Horizontal Branch of the Carina Dwarf Spheroidal Galaxy by means of synthetic modelling techniques, taking consistently into account the star formation history and metallicity evolution as determined from main sequence and red giant branch spectroscopic observations. We found that a range of integrated red giant branch mass loss values of 0.1-0.14 M, increasing with metallicity, is able to reproduce the colour extension of the old Horizontal Branch. However, leaving the mass loss as the only free parameter is not enough to match the detailed morphology of Carina Horizontal Branch. We explored the role played by the star formation history on the discrepancies between synthetic and observed Horizontal Branches. We derived a toy bursty star formation history that reproduces the horizontal branch star counts, and also matches qualitatively the red giant and the turn off regions. This star formation history is made of a subset of age and [M/H] components of the star formation ...

  15. Three Parameters for the Horizontal-Branch Morphology in Globular Clusters

    CERN Document Server

    Milone, A P

    2013-01-01

    The horizontal branch (HB) morphology of globular clusters (GCs) is mainly described by metallicity. The fact that some clusters with almost the same metallicity exhibit different HB demonstrates that other parameters are at work. We present results from the analysis of the CMD of 72 GCs obtained with the Advanced Camera for Survey (ACS) of the Hubble Space Telescope (HST). We find a significant correlation between the HB color extension and the mass of the hosting cluster, while the color distance between the HB and the red-giant branch (RGB) depends on metallicity and age. We suggest that age and metallicity are the main global parameters of the HB morphology in GCs, while the HB extension is mainly due to internal helium variation, associated to multiple stellar populations.

  16. The temperature distribution of horizontal branch stars: methods and first results

    CERN Document Server

    Lagioia, E P; Ferraro, F R; Salaris, M; Lanzoni, B; Pietrinferni, A; Cassisi, S

    2014-01-01

    As part of a large project aimed at characterizing the ultraviolet (UV) properties of globular clusters, we present here a theoretical and observational analysis aimed at setting the framework for the determination of horizontal branch (HB) temperature distributions. Indeed this is a crucial information to understand the physical parameters shaping the HB morphology in globular clusters and to interpret the UV emission from unresolved stellar systems. We found that the use of zero age HB color-Teff relations is a robust way to derive effective temperatures of individual HB stars. We investigated the most suitable colors for temperature estimates, and the effect on the color-Teff relations of variations of the initial chemical composition, and of the evolution off the zero age horizontal branch. As a test case, we applied our color-Teff calibrations to the Galactic globular cluster M15. The photometry of M15 has been obtained with the Wide Field and Planetary Camera 2 on board the HST. The HB of M15 turned out...

  17. Inclusion of horizontal branch stars in the derivation of star formation histories of dwarf galaxies: The Carina dSph

    Science.gov (United States)

    Savino, Alessandro; Salaris, Maurizio; Tolstoy, Eline

    2015-11-01

    We present a detailed analysis of the horizontal branch of the Carina dwarf spheroidal galaxy by means of synthetic modelling techniques, taking consistently into account the star formation history and metallicity evolution as determined from main sequence and red giant branch spectroscopic observations. We found that a range of integrated red giant branch mass loss values of 0.1-0.14 M⊙ increasing with metallicity is able to reproduce the colour extension of the old horizontal branch. Nonetheless, leaving the mass loss as the only free parameter is not enough to match the detailed morphology of Carina horizontal branch. We then investigated the role played by the star formation history on the discrepancies between synthetic and observed horizontal branches. We derived a "toy" bursty star formation history that reproduces well the observed horizontal branch star counts, and also matches qualitatively the red giant and the turn-off regions. This bursty star formation history is made of a subset of age and [M/H] components of the star formation history based on turn off and red giants only, and entails four separate bursts of star formation of different strengths, centred at 2, 5, 8.6, and 11.5 Gyr, respectively, with mean [M/H] decreasing from ~-1.7 to ~-2.2 when the age of the burst increases, and with a Gaussian spread of σ 0.1 dex around these mean values. The comparison between the metallicity distribution function of our bursty star formation history and the one measured from the infrared CaT feature using a CaT-[Fe/H] calibration shows a qualitative agreement, once the range of [Ca/Fe] abundances measured in a sample of Carina stars have been taken into account, that causes a bias of the derived [Fe/H] distribution toward values that are too low. In conclusion, we show how the information contained within the horizontal branch of Carina (and dwarf galaxies in general) can be extracted and interpreted to refine the star formation history derived exclusively

  18. The mosaic multiple stellar populations in ω Centauri: the horizontal branch and the main sequence

    Science.gov (United States)

    Tailo, M.; Di Criscienzo, M.; D'Antona, F.; Caloi, V.; Ventura, P.

    2016-04-01

    We interpret the stellar population of ω Centauri by means of a population synthesis analysis, following the most recent observational guidelines for input metallicities, helium and [(C+N+O)/Fe] contents. We deal at the same time with the main sequences, sub-giant and horizontal branch (HB) data. The reproduction of the observed colour-magnitude features is very satisfying and bears interesting hints concerning the evolutionary history of this peculiar stellar ensemble. Our main results are: (1) no significant spread in age is required to fit the colour-magnitude diagram. Indeed, we can use coeval isochrones for the synthetic populations, and we estimate that the ages fall within a ˜0.5 Gyr time interval; in particular the most metal-rich population can be coeval (in the above meaning) with the others, if its stars are very helium-rich (Y ˜ 0.37) and with the observed CNO enhancement ([(C+N+O)/Fe] = +0.7); (2) a satisfactory fit of the whole HB is obtained, consistent with the choice of the populations providing a good reproduction of the main sequence and sub-giant data; (3) the split in magnitude observed in the red HB is well reproduced assuming the presence of two stellar populations in the two different sequences observed: a metal-poor population made of stars evolving from the blue side (luminous branch) and a metal richer one whose stars are in a stage closer to the zero age HB (dimmer branch). This modelization also fits satisfactorily the period and the [Fe/H] distribution of the RR Lyrae stars.

  19. Global and nonglobal parameters of horizontal-branch morphology of globular clusters

    International Nuclear Information System (INIS)

    The horizontal-branch (HB) morphology of globular clusters (GCs) is mainly determined by metallicity. However, the fact that GCs with almost the same metallicity exhibit different HB morphologies demonstrates that at least one more parameter is needed to explain the HB morphology. It has been suggested that one of these should be a global parameter that varies from GC to GC and the other a nonglobal parameter that varies within the GC. In this study we provide empirical evidence corroborating this idea. We used the photometric catalogs obtained with the Advanced Camera for Surveys of the Hubble Space Telescope and analyze the color-magnitude diagrams of 74 GCs. The HB morphology of our sample of GCs has been investigated on the basis of the two new parameters L1 and L2 that measure the distance between the red giant branch and the coolest part of the HB and the color extension of the HB, respectively. We find that L1 correlates with both metallicity and age, whereas L2 most strongly correlates with the mass of the hosting GC. The range of helium abundance among the stars in a GC, characterized by ΔY and associated with the presence of multiple stellar populations, has been estimated in a few GCs to date. In these GCs we find a close relationship among ΔY, GC mass, and L2. We conclude that age and metallicity are the main global parameters, while the range of helium abundance within a GC is the main nonglobal parameter defining the HB morphology of Galactic GCs.

  20. THE HORIZONTAL BRANCH OF NGC 1851: CONSTRAINTS FROM ITS RR LYRAE VARIABLES

    International Nuclear Information System (INIS)

    We use the pulsational properties of the RR Lyrae variables in the globular cluster NGC 1851 to obtain detailed constraints of the various sub-stellar populations present along its horizontal branch. On the basis of detailed synthetic horizontal branch modeling, we find that minor helium variations (Y ∼ 0.248-0.280) are able to reproduce the observed periods and amplitudes of the RR Lyrae variables, as well as the frequency of fundamental and first-overtone RR Lyrae stars. Comparison of number ratios among the blue and red horizontal branch components and the two observed subgiant branches also suggest that the RR Lyrae variables originated from the progeny of the bright subgiant branch. The RR Lyrae variables with slightly enhanced helium (Y ∼ 0.270-0.280) have longer periods at a given amplitude, as is seen with Oosterhoff II (OoII) RR Lyrae variables, whereas the RR Lyrae variables with Y ∼ 0.248-0.270 have shorter periods, exhibiting properties of Oosterhoff I (OoI) variables. This correlation does suggest that the pulsational properties of RR Lyrae stars can be very useful for tracing the various subpopulations and can provide suitable constraints on the multiple population phenomenon. It appears to be of great interest to explore whether this conclusion can be generalized to other globular clusters hosting multiple populations.

  1. Chronography of the Milky Way's Halo System with Field Blue Horizontal-Branch Stars

    CERN Document Server

    Santucci, R M; Placco, V M; Carollo, D; Rossi, S; Lee, Y S; Denissenkov, P; Tumlinson, J; Tissera, P B

    2015-01-01

    In a pioneering effort, Preston et al. reported that the colors of blue horizontal-branch (BHB) stars in the halo of the Galaxy shift with distance, from regions near the Galactic center to about 12 kpc away, and interpreted this as a correlated variation in the ages of halo stars, from older to younger, spanning a range of a few Gyrs. We have applied this approach to a sample of some 4700 spectroscopically confirmed BHB stars selected from the Sloan Digital Sky Survey to produce the first "chronographic map" of the halo of the Galaxy. We demonstrate that the mean de-reddened g$-$r color, , increases outward in the Galaxy from $-$0.22 to $-$0.08 (over a color window spanning [$-$0.3:0.0]) from regions close to the Galactic center to ~40 kpc, independent of the metallicity of the stars. Models of the expected shift in the color of the field BHB stars based on modern stellar evolutionary codes confirm that this color gradient can be associated with an age difference of roughly 2-2.5 Gyrs, with the oldest stars ...

  2. The mosaic multiple stellar populations in $\\omega$ Centauri : the Horizontal Branch and the Main Sequence

    CERN Document Server

    Tailo, Marco; D'Antona, Francesca; Caloi, Vittoria; Ventura, Paolo

    2016-01-01

    We interpret the stellar population of $\\omega$ Centauri by means of a population synthesis analysis, following the most recent observational guidelines for input metallicities, helium and [(C+N+O)/Fe] contents. We deal at the same time with the main sequences, sub-giant and horizontal branch data. The reproduction of the observed colour magnitude features is very satisfying and bears interesting hints concerning the evolutionary history of this peculiar stellar ensemble. Our main results are: 1) no significant spread in age is required to fit the colour-magnitude diagram. Indeed we can use coeval isochrones for the synthetic populations, and we estimate that the ages fall within a $\\sim 0.5$ Gyr time interval; in particular the most metal rich population can be coeval (in the above meaning) with the others, if its stars are very helium--rich (Y$\\sim$0.37) and with the observed CNO enhancement ([(C+N+O)/Fe] = + 0.7); 2) a satisfactory fit of the whole HB is obtained, consistent with the choice of the populati...

  3. Two-phase flow through small branches in a horizontal pipe with stratified flow

    International Nuclear Information System (INIS)

    This report presents the description and results of experiments designed to determine the mass flow rate and quality through a small break at the bottom, the top or the side of a main pipe with stratified gas-liquid flow. If the interface level is far below (above) the branch, only single-phase gas (liquid) flow enters the branch. For smaller distances the interface is locally deformed because of the pressure decrease due to the fluid acceleration near the branch inlet (Bernoulli effect) and liquid (gas) can be entrained. This report contains photographs illustrating the flow phenomena as well as a general correlation to determine the beginning of entrainment. Results are presented on the branch mass flow rate and quality as a function of a normalized distance between the interface and the branch inlet. A model was developed which enables to predict the branch quality and mass flux. Results from air-water flow through horizontal branches, were extrapolated for steam water flow at high pressure with critical branch mass flux. (orig./HP)

  4. Cyanogen distribution of M4 and the possible connection between horizontal branch morphology and chemical inhomogeneity

    International Nuclear Information System (INIS)

    A spectroscopic survey of 45 red giants in the globular cluster M4 has been completed with a view to ascertaining whether the bimodal distribution of stars on the horizontal branch (Lee) is accompanied by a cyanogen dichotomy on the giant branch, similar to the situation found in NGC 6752. From analysis of some 118 spectra, it is concluded that the red giants in M4 (in the magnitude range M/sub V/approx.0.3 to -1.2) do show a bimodal cyanogen distribution. There appears also to be an anticorrelation between the behavior of CN and CH. A working hypothesis is proposed which will explain most of the known peculiarities of the three globular clusters 47 Tuc, M4, and NGC 6752, for which comprehensive cyanogen surveys are available. It is suggested that there is a spectrum of core rotational velocity in the main-sequence stars of globular clusters. Beyond some critical value of the rotational velocity, a star will mix the products of the CN cycle into its outer layers, while still on or near the main sequence. The range in angular momentum leads also to a range in luminosity at which helium flash occurs and, thereby, to a range in envelope mass on the horizontal branch. Both the distribution of the products of mixing in the red giants and that of stars along the horizontal branch are thus determined by the spectrum of angular velocities in the cluster stars. This work thus supports the contention that core rotation is a parameter which effects horizontal branch morphology (the case is made that it should be regarded as the third parameter). The hypothesis has the advantage that it makes several predictions which are open to observational test

  5. Discovery of Extended Blue Horizontal Branches in Two Metal-Rich Globular Clusters

    CERN Document Server

    Rich, R M; Djorgovski, S G; Piotto, G; King, I R; Renzini, A; Phinney, E S; Dorman, B; Liebert, J; Meylan, G; Sosin, Craig; Piotto, Giampaolo; King, Ivan R.; Renzini, Alvio; Dorman, Ben; Liebert, James; Meylan, Georges

    1997-01-01

    We have used WFPC2 to construct B, V color-magnitude diagrams of four metal-rich globular clusters, NGC 104 (47 Tuc), NGC 5927, NGC 6388, and NGC 6441. All four clusters have well populated red horizontal branches (RHB), as expected for their metallicity. However, NGC 6388 and 6441 also exhibit a prominent blue HB (BHB) extension, including stars reaching as faint in V as the turnoff luminosity. This discovery demonstrates directly for the first time that a major population of hot HB stars can exist in old, metal-rich systems. This may have important implications for the interpretation of the integrated spectra of elliptical galaxies. The cause of the phenomenon remains uncertain. We examine the possibility that NGC 6388 and 6441 are older than the other clusters, but a simple difference in age may not be sufficient to produce the observed distributions along the HB. The high central densities in NGC 6388 and 6441 suggest that the existence of the blue HB (BHB) tails might be caused by stellar interactions in...

  6. Physical Parameters of Hot Horizontal-Branch Stars in NGC 6752: Deep Mixing and Radiative Levitation

    Science.gov (United States)

    Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Heber, U.; Catelan, M.

    1999-01-01

    Atmospheric parameters (T(sub eff), log g and log n(sub He)/n(sub H-dot)) are derived for 42 hot horizontal branch (HB) stars in the globular cluster NGC 6752. For 19 stars Mg II and Fe II lines are detected indicating an iron enrichment by a factor 50 on average with respect to the cluster abundance whereas the magnesium abundances are consistent with the cluster metallicity. This finding adds to the growing evidence that radiative levitation plays a significant role in determining the physical parameters of blue HB stars. Indeed, we find that iron enrichment can explain part, but not all, of the problem of anomalously low gravities along the blue HB. Thus the physical parameters of horizontal branch stars hotter than about 11,500 K in NGC 6752, as derived in this paper, are best explained by a combination of helium mixing and radiative levitation effects.

  7. Coupling between the 45 Hz Horizontal-Branch Oscillation and the Normal-Branch Oscillation in Scorpius X-1

    Science.gov (United States)

    Yu, Wenfei

    2007-04-01

    The observations of the bright persistent neutron star low-mass X-ray binary (LMXB) Sco X-1 performed with the Rossi X-Ray Timing Explorer (RXTE) show a ~6 Hz normal-branch oscillation (NBO), a ~45 Hz horizontal-branch oscillation (HBO), and twin kilohertz quasi-periodic oscillations (kHz QPOs) on its normal branch simultaneously. We have found that the fractional amplitude of the HBO corresponding to the NBO phase of high flux is 1.1%, while that of the NBO phase of low flux is undetectable, with a 3 σ upper limit of 0.4%, implying that the HBO strength varies with the NBO phase in a manner opposite that of the lower kHz QPO previously found, and suggests that the condition for the generation of the HBO is met when the NBO flux is high. The 6 Hz NBO in Sco X-1 connects the 45 Hz HBO and the twin kHz QPO together, showing a unique picture indicating a coupling between the QPOs, which has never been observed in other neutron star LMXBs. We discuss the implications for current models of the 45 Hz HBO, the 6 Hz NBO, and the twin kHz QPOs.

  8. Coupling between the 45 Hz Horizontal-Branch Oscillation and the Normal Branch Oscillation in Scorpius X-1

    CERN Document Server

    Yu, W

    2007-01-01

    The observations of the bright persistent neutron star low-mass X-ray binary (LMXB) Sco X-1 performed with the {\\it Rossi X-ray Timing Explorer} (RXTE) show a $\\sim$ 6 Hz normal-branch oscillation (NBO), a $\\sim$ 45 Hz horizontal-branch oscillation (HBO), and twin kHz quasi-periodic oscillations (QPOs) on its normal branch simultaneously. We have found that the fractional amplitude of the HBO corresponding to the NBO phase of high flux is 1.1%, while that of the NBO phase of low flux is undetectable, with a 3$\\sigma$ upper limit of 0.4%, implying that the HBO strength varies with the NBO phase in an opposite way to that of the lower kHz QPO previously found, and suggests that the condition for the generation of the HBO is met when the NBO flux is high. The 6 Hz NBO in Sco X-1 connects the 45 Hz HBO and the twin kHz QPO together, showing a unique picture indicating a coupling between the QPOs, which has never been observed in other neutron star LMXBs. We discuss the implications for current models of the 45 Hz...

  9. THE TEMPERATURE DISTRIBUTION OF HORIZONTAL BRANCH STARS: METHODS AND FIRST RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Lagioia, E. P.; Dalessandro, E.; Ferraro, F. R.; Lanzoni, B. [Dipartimento di Fisica e Astronomia, Università degli Studi di Bologna, via Ranzani 1, I-40126 Bologna (Italy); Salaris, M. [Astrophysics Research Institute, Liverpool John Moores University, IC2 Liverpool Science Park, 146 Brownlow Hill, L3 5RF Liverpool (United Kingdom); Pietrinferni, A.; Cassisi, S., E-mail: edoardo.lagioia2@unibo.it [INAF-Osservatorio Astronomico di Collurania, via Mentore Maggini, I-64100 Teramo (Italy)

    2015-02-10

    As part of a large project aimed at characterizing the ultraviolet (UV) properties of globular clusters, we present here a theoretical and observational analysis aimed at setting the framework for the determination of horizontal branch (HB) temperature distributions. Indeed this is crucial information needed to understand the physical parameters shaping the HB morphology in globular clusters and to interpret the UV emission from unresolved stellar systems. We found that the use of zero age HB color-T {sub eff} relations is a robust way to derive effective temperatures of individual HB stars. We investigated the most suitable colors for temperature estimates and the effect on the color-T {sub eff} relations of variations of the initial chemical composition and the evolution off the zero age HB. As a test case, we applied our color-T {sub eff} calibrations to the Galactic globular cluster M15. The photometry of M15 has been obtained with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. The HB of M15 turned out to have a multimodal distribution, with a main component peaking at T{sub eff} ∼ 8000 K and confined below T{sub eff} ∼ 10,000 K. The second component peaks at T{sub eff} ∼ 14,000 K and extends up to T{sub eff} ∼ 20,000 K. The vast majority ( ∼ 95%) of the HB stars in M15 is below 20,000 K, in agreement with the lack of a well populated extreme HB observed in other metal-poor globular clusters. We also verified that the temperatures derived with our analysis are consistent with spectroscopic estimates available in the literature.

  10. The Horizontal Branch in the UV Colour Magnitude Diagrams. II. The case of M3, M13 and M79

    CERN Document Server

    Dalessandro, Emanuele; Ferraro, Francesco R; Mucciarelli, Alessio; Cassisi, Santi

    2012-01-01

    We present a detailed comparison between far-UV/optical colour Magnitude Diagrams obtained with high-resolution Hubble Space Telescope data and suitable theoretical models for three Galactic Globular Clusters: M3, M13 and M79. These systems represents a classical example of clusters in the intermediate metallicity regime that, even sharing similar metal content and age, show remarkably different Horizontal Branch morphologies. As a consequence, the observed differences in the colour distributions of Horizontal Branch stars cannot be interpreted in terms of either first (metallicity) or a second parameter such as age. We investigate here the possible role of variations of initial Helium abundance (Y). Thanks to the use of a proper setup of far-UV filters, we are able to put strong constraints on the maximum Y (Y_{max}) values compatible with the data. We find differences Delta Y_{max} ~ 0.02-0.04 between the clusters with M13 showing the largest value (Y_{max} ~ 0.30) and M3 the smallest (Y_{max} ~ 0.27). In g...

  11. DAYLIGHTING PERFORMANCE OF HORIZONTAL LIGHT PIPE BRANCHING ON OPEN PLAN OFFICE SPACE

    Directory of Open Access Journals (Sweden)

    Feny ELSIANA

    2015-12-01

    Full Text Available For daylighting purpose, office buildings should have a shallow plan and increase the ratio of surface to building’s volume. However, intensive use of air-conditioning drives office building’s plan to be deep with a minimum surface to volume ratio. This leads to the presence of areas that have insufficient daylight level at the work plane. Considering limitations of some daylighting methods in distributing daylight to these areas, Horizontal Light Pipe (HLP was selected. The aim of this research was to evaluate and explain the effect of HLP branching on daylight quantity and distribution inside open plan office space. Experimental with simulation as a tool was used as the research method. HLP branching’s uniformity ratio, illuminance and Daylight Factor were compared with unbranching HLP, simultaneously with daylighting standards. Results showed that office space with HLP-L branching had higher daylight level than HLP-T branching, 296 lux and 295 lux, HLP-L and HLP-T, respectively. However, HLP-T branching distributed daylight more evenly than HLP-L branching, with uniformity ratio as 1.49:1 and 1.50:1, HLP-T and HLP-L, respectively. Both of them met the illuminance target value and uniformity at work plane. Light’s deflection and improvement amount of opening distribution decreased average illuminance and Daylight Factor up to 3.59%. Those also decreased uniformity of daylight inside the space.

  12. Gas-liquid flow in dividing Tee-junctions with a horizontal inlet and different branch orientations and diameters

    International Nuclear Information System (INIS)

    An extensive data base is presented, summarizing previous and new experiments, on the phase redistribution and pressure differences for a gas-liquid mixture flowing through the horizontal inlet pipe (diameter D1=50 mm) of a Tee-junction. Branch to inlet diameter ratios of D3/D1 = 1; 0.52; 0.2; and 0.08 were investigated. The branch orientation was horizontal, vertical upward or vertical downward. Mostly air-water experiments were performed with pressures between 0.4 and 1 MPa. Experiments with steam-water flows at pressures between 1.5 and 10 MPa were performed for D3/D1 = 1 and a horizontal branch. The results on phase redistribution and pressure drop are compared with other experimental data and model predictions, published previously by various authors. There are clear trends in the experimental data on phase redistribution: For the upward branch, the branch quality x3 is the highest, for the downward branch the lowest for constant inlet conditions. With decreasing branch diameter, in general, the branch quality increases for the same branch mass flow rate. This tendency can be reversed for D3/D13/D1≅1 and inclined branch due to flow reversal effects in the branch pipe. (orig./GL)

  13. An HST/WFC3 view of stellar populations on the Horizontal Branch of NGC 2419

    CERN Document Server

    Di Criscienzo, M; Milone, A P; D'Antona, F; Ventura, P; Dotter, A; Brocato, E

    2015-01-01

    We use images acquired with the Hubble Space Telescope Wide Field Camera 3 and new models to probe the Horizontal Branch (HB) population of the We use images acquired with the Hubble Space Telescope Wide Field Camera 3 and new models to probe the horizontal branch (HB) population of the Galactic globular cluster (GC) NGC 2419. A detailed analysis of the composite HB highlights three populations:(1) the blue luminous HB, hosting standard helium stars (Y=0.25) with a very small spread of mass, (2) a small population of stars with intermediate helium content (0.26branch (AGB) stars of the same metallicity as NGC 2419. Thi...

  14. Chronography of the Milky Way's Halo System with Field Blue Horizontal-Branch Stars

    Science.gov (United States)

    Beers, Timothy C.; Placco, Vinicius M.; Carollo, Daniela; Santucci, Rafael; Rossi, Siliva; Lee, Young Sun; Denissenkov, Pavel; Tumlinson, Jason; Tissera, Patricia; Lentner, Geoffrey

    2016-01-01

    In a pioneering effort, Preston et al. (1991, AJ 375, 121) reported that the colors of blue horizontal-branch (BHB) stars in the halo of the Galaxy shift with distance, from regions near the Galactic center to about 12 kpc away, and interpreted this as a correlated variation in the ages of halo stars, from older to younger, spanning a range of a few Gyrs. We have applied this approach to a sample of some 4700 spectroscopically confirmed BHB stars selected from the Sloan Digital Sky Survey to produce the first "chronographic map" of the halo of the Galaxy.We demonstrate that the mean de-reddened g-r color increases outward in the Galaxy from -0.22 to -0.08 (over a color window spanning [-0.3:0.0]) from regions close to the Galactic center to ~40 kpc, independent of the metallicity of the stars. Models of the expected shift in the color of the field BHB stars based on modern stellar evolutionary codes confirm that this color gradient can be associated with an age difference of roughly 2-2.5 Gyrs, with the oldest stars concentrated in the central ~15 kpc of the Galaxy. Within this centralregion, which we refer to as the Ancient Chronographic Sphere (ACS), the age difference spans a mean color range of about 0.05 mag (~0.8 Gyrs). Interestingly, the ACS extends far enough to include the Solar Neighborhood, suggesting that ancient metal-poor stars should be readily detectable in the vicinity of the Sun. Furthermore, we show that chronographic maps can be used to identify individual substructures, such as the Sagittarius Stream, and overdensities in the direction of Virgo and Monoceros, based on the observed contrast in their mean BHB colors with respect to the foreground/background field population.We acknowledge partial support from the grant PHY 14-30152; Physics Frontier Center/JINA Center for the Evolution of the Elements (JINA-CEE), awarded by the US National Science Foundation.

  15. The accretion rate independence of horizontal branch oscillation in XTE J1701-462

    International Nuclear Information System (INIS)

    We study the temporal and energy spectral properties of the unique neutron star low-mass X-ray binary XTE J1701-462. Assuming the horizontal branch/normal branch (HB/NB) vertex as a reference position of the accretion rate, the horizontal branch oscillation (HBO) of the HB/NB vertex is roughly 50 Hz. It indicates that the HBO is independent of the accretion rate or the source intensity. The spectral analysis shows Rin∝ M-dot Disk2.9±0.09 in the HB/NB vertex and Rin∝ M-dot Disk1.7±0.06 in the NB/flaring branch (FB) vertex, which implies that different accretion rates may be produced in the HB/NB and NB/FB vertex. The Comptonization component could be fitted by a constrained broken power law or nthComp. Unlike GX 17+2, the frequencies of HBO positively correlate with the inner disk radius, which contradict with the prediction of the Lense-Thirring precession model. XTE J1701-462, both in the Cyg-like phase and in the Sco-like phase, follows a positive correlation between the break frequency of broadband noise and the characteristic frequency of HBO, which is called the W-K relation. An anticorrelation between the frequency of HBO and photon energy is observed. Moreover, the rms of HBO increases with photon energy until ∼10 keV. We discuss the possible origin of HBO from the corona in XTE J1701-462.

  16. The accretion rate independence of horizontal branch oscillation in XTE J1701-462

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhaosheng; Chen, Li; Bu, Qingcui; Wang, Dehua [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Qu, Jinlu [Laboratory for Particle Astrophysics, Institute of High Energy Physics, CAS, Beijing 100049 (China); Xu, Renxin, E-mail: lizhaosheng@pku.edu.cn, E-mail: chenli@bnu.edu.cn, E-mail: r.x.xu@pku.edu.cn, E-mail: qujl@ihep.ac.cn [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

    2014-05-10

    We study the temporal and energy spectral properties of the unique neutron star low-mass X-ray binary XTE J1701-462. Assuming the horizontal branch/normal branch (HB/NB) vertex as a reference position of the accretion rate, the horizontal branch oscillation (HBO) of the HB/NB vertex is roughly 50 Hz. It indicates that the HBO is independent of the accretion rate or the source intensity. The spectral analysis shows R{sub in}∝ M-dot {sub Disk}{sup 2.9±0.09} in the HB/NB vertex and R{sub in}∝ M-dot {sub Disk}{sup 1.7±0.06} in the NB/flaring branch (FB) vertex, which implies that different accretion rates may be produced in the HB/NB and NB/FB vertex. The Comptonization component could be fitted by a constrained broken power law or nthComp. Unlike GX 17+2, the frequencies of HBO positively correlate with the inner disk radius, which contradict with the prediction of the Lense-Thirring precession model. XTE J1701-462, both in the Cyg-like phase and in the Sco-like phase, follows a positive correlation between the break frequency of broadband noise and the characteristic frequency of HBO, which is called the W-K relation. An anticorrelation between the frequency of HBO and photon energy is observed. Moreover, the rms of HBO increases with photon energy until ∼10 keV. We discuss the possible origin of HBO from the corona in XTE J1701-462.

  17. The Accretion Rate Independence of Horizontal Branch Oscillation in XTE J1701-462

    Science.gov (United States)

    Li, Zhaosheng; Chen, Li; Qu, Jinlu; Bu, Qingcui; Wang, Dehua; Xu, Renxin

    2014-05-01

    We study the temporal and energy spectral properties of the unique neutron star low-mass X-ray binary XTE J1701-462. Assuming the horizontal branch/normal branch (HB/NB) vertex as a reference position of the accretion rate, the horizontal branch oscillation (HBO) of the HB/NB vertex is roughly 50 Hz. It indicates that the HBO is independent of the accretion rate or the source intensity. The spectral analysis shows R_{in}\\propto \\dot{M}_{Disk}^{2.9+/- 0.09} in the HB/NB vertex and R_{in}\\propto \\dot{M}_{Disk}^{1.7+/- 0.06} in the NB/flaring branch (FB) vertex, which implies that different accretion rates may be produced in the HB/NB and NB/FB vertex. The Comptonization component could be fitted by a constrained broken power law or nthComp. Unlike GX 17+2, the frequencies of HBO positively correlate with the inner disk radius, which contradict with the prediction of the Lense-Thirring precession model. XTE J1701-462, both in the Cyg-like phase and in the Sco-like phase, follows a positive correlation between the break frequency of broadband noise and the characteristic frequency of HBO, which is called the W-K relation. An anticorrelation between the frequency of HBO and photon energy is observed. Moreover, the rms of HBO increases with photon energy until ~10 keV. We discuss the possible origin of HBO from the corona in XTE J1701-462.

  18. Chemical Abundances and Rotation Velocities of Blue Horizontal-Branch Stars in Six Globular Clusters

    CERN Document Server

    Behr, B B

    2003-01-01

    High-resolution spectroscopic measurements of blue horizontal-branch stars in six metal-poor globular clusters -- M3, M13, M15, M68, M92, and NGC 288 -- reveal remarkable variations in photospheric composition and rotation velocity as a function of a star's position along the horizontal branch. For the cooler stars (Teff < 11200 K), the derived abundances are in good agreement with the canonical cluster metallicities, and we find a wide range of v sin i rotation velocities, some as high as 40 km/s. In the hotter stars, however, most metal species are strongly enhanced, by as much as 3 dex, relative to the expected cluster metallicity, while helium is depleted by 2 dex or more. In addition, the hot stars all rotate slowly, with v sin i < 8 km/s. The anomalous abundances appear to be due to atomic diffusion mechanisms -- gravitational settling of helium, and radiative levitation of metals -- in the non-convective atmospheres of these hot stars. We discuss the influence of these photospheric metal enhancem...

  19. Blue Horizontal-Branch Stars The "Jump" in Strömgren u, Low Gravities, and Radiative Levitation of Metals

    CERN Document Server

    Grundahl, F; Landsman, W B; Stetson, P B; Andersen, M I

    1999-01-01

    We study the ``jump'' in the blue horizontal--branch (BHB) distribution first detected by Grundahl et al. (1998) in the Galactic globular cluster (GC) M13. On the basis of Stromgren photometry for a sample of fourteen GC's we show that: 1) The jump is best characterized as a systematic shift, on a (u, u-y) color-magnitude diagram, from canonical zero-age HB (ZAHB) models, in the sense that the stars appear brighter and/or hotter than the models; 2) the jump is a ubiquitous phenomenon, ocurring over the temperature range 11,500 < Teff < 20,000K; 3) An analogous feature is present in (log g, log Teff) diagrams -- indicating a common physical origin for the two phenomena; 4) The physical mechanism responsible for the jump phenomenon is most likely radiative levitation of iron and other

  20. The Hottest Horizontal-Branch Stars in Omega Centauri: Late Hot Flasher vs. Helium Enrichment

    Science.gov (United States)

    Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A V.; Calamida, A.; Monelli, M.; Nonino, M.

    2007-01-01

    UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario here stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified from existing data. We want to determine effective temperatures, surface gravities and abundances of He, C, N in blue hook and canonical extreme horizontal branch (EHB) star candidates. Moderately high resolution spectra of stars at the hot end of the blue horizontal branch in the globular cluster omega Cen were analysed for atmospheric parameters (T(sub eff), log g) and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 37% of our stars are helium-poor (log nHe/nH less than -2), 49% have solar helium abundance within a factor of 3 (-1.5 less than or equal to log nHe/nH less than or equal to -0.5) and 14% are helium rich (log nHe/nH greater than -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 30% of the hottest HB stars in omega Centauri show helium abundances well above the predictions from the helium enrichment scenario (Y = 0.42 corresponding to log nHe/nH approximately equal to -0.74). In addition the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

  1. Experimental rig for study of discharges through small branches in horizontal pipe with stratified flow

    International Nuclear Information System (INIS)

    Full text: The paper describes an experimental rig for the simulation study of prototype PHWR header-feeder configuration. The rig consists of test chamber with scale down header-feeder configuration in the form of replaceable test piece. The test piece consists of semi-circular header of 54.24 mm diameter and five branches of 8.20 mm diameter and is placed into horizontal pipe of 600 mm NB and 12 m long under stratified flow condition. The proposed rig can carry out test for various interface level of liquid for test chamber pressure of 5.0 bar at test piece. Test chamber to separators lines are of equal hydraulic resistance. The mass flow measurement of air and water can be with over lapping range of air flow meter bank and water flow meter bank

  2. Constraints on Helium Enhancement in the Globular Cluster M3 (NGC 5272): The Horizontal Branch Test

    Science.gov (United States)

    Catelan, M.; Grundahl, F.; Sweigart, A. V.; Valcarce, A. A. R.; Cortes, C.

    2007-01-01

    It has recently been suggested that the presence of multiple populations showing various amounts of helium enhancement is a common feature among globular star clusters. In this scenario, such a helium enhancement would be particularly apparent in the enhanced luminosity of thc blue horizontal branch (HB) stars compared to the red HB stars. In this Letter, wc test this scenario in the case of the Galactic globular cluster M3 (NGC 5272), using high-precision Stromgren photometry and spectroscopic gravities for blue HB stars. We find that any helium enhancement among the cluster's blue HB stars must be significantly less than I%, thus ruling out the much higher helium enhancements that have been proposed in the literature.

  3. Anomalous scaling in an age-dependent branching model

    OpenAIRE

    Keller-Schmidt, Stephanie; Tugrul, Murat; Eguiluz, Victor M.; Hernandez-Garcia, Emilio; Klemm, Konstantin

    2010-01-01

    We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age $\\tau$ as $\\tau^{-\\alpha}$. Depending on the exponent $\\alpha$, the scaling of tree depth with tree size $n$ displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition ($\\alpha=1$) tree depth grows as $(\\log n)^2$. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus p...

  4. Anomalous scaling in an age-dependent branching model

    OpenAIRE

    Keller-Schmidt, Stephanie; Tugrul, Murat; Eguíluz, Víctor M.; Hernández-García, Emilio; Klemm, Konstantin

    2015-01-01

    We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age $\\tau$ as $\\tau^{-\\alpha}$. Depending on the exponent $\\alpha$, the scaling of tree depth with tree size $n$ displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition ($\\alpha=1$) tree depth grows as $(\\log n)^2$. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus p...

  5. Level of helium enhancement among M3's horizontal branch stars

    Science.gov (United States)

    Valcarce, A. A. R.; Catelan, M.; Alonso-García, J.; Contreras Ramos, R.; Alves, S.

    2016-04-01

    Context. The color and luminosity distribution of horizontal branch (HB) stars in globular clusters (GCs) are sensitive probes of the original helium abundances of those clusters. In this sense, recently the distributions of HB stars in GC color-magnitude diagrams (CMDs) have been extensively used as indicators of possible variations in the helium content Y among the different generations of stars within individual GCs. However, recent analyses based on visual and near-ultraviolet (UV) CMDs have provided conflicting results. Aims: To clarify the situation, we address the optimum ranges of applicability (in terms of the Teff range covered by the HB stars) for visual and near-UV CMDs, as far as application of this "HB Y test" goes. Methods: We considered both Strömgren and Hubble Space Telescope (HST) bandpasses. In particular, we focus on the F336W filter of the HST, but also discuss several bluer UV bandpasses, such as F160BW, F255W, and F300W. Using the Princeton-Goddard-PUC (PGPUC) code, we computed a large set of zero-age HB (ZAHB) loci and HB evolutionary models for masses ranging from MHB = 0.582 to 0.800 M⊙, assuming an initial helium abundance Y = 0.246, 0.256, and 0.266, with a global metallicity Z = 0.001. The results of these calculations were compared against the observations of M3 (NGC 5272), with special attention on the y vs. (b - y) and F336W vs. (F336W-F555W) CMDs. Results: Our results indicate that, from an evolutionary perspective, the distributions of HB stars in the y vs. (b - y) plane can be a reliable indicator of the He content in cool blue HB (BHB) stars, particularly when a differential comparison between blue and red HB stars is carried out in the range Teff ≲ 8300 K. Conversely, we demonstrate that CMDs using the F336W filter have a much less straightforward interpretation at the cool end of the BHB because the distributions of HB stars in the F336W vs. (F336W-F555W) plane, for instance, are affected by a triple degeneracy effect. In

  6. Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars

    Science.gov (United States)

    Carney, Bruce W.; Gray, David F.; Yong, David; Latham, David W.; Manset, Nadine; Zelman, Rachel; Laird, John B.

    2008-03-01

    We report the results for rotational velocities, Vrot sin i, and macroturbulence dispersions, ζRT, for 12 metal-poor field red giant branch (RGB) stars and 7 metal-poor field red horizontal branch (RHB) stars. The results are based on Fourier transform analyses of absorption line profiles from high-resolution (R ≈ 120,000), high-S/N (≈215 per pixel; ≈345 per resolution element) spectra obtained with the Gecko spectrograph at the Canada-France-Hawaii Telescope (CFHT). The stars were selected from the authors' previous studies of 20 RHB and 116 RGB stars, based primarily on larger-than-average line-broadening values. We find that ζRT values for the metal-poor RGB stars are very similar to those for metal-rich disk giants studied earlier by Gray and his collaborators. Six of the RGB stars have small rotational values, less than 2.0 km s-1, while five show significant rotation/enhanced line broadening, over 3 km s-1. We confirm the rapid rotation rate for RHB star HD 195636, found earlier by Preston. This star's rotation is comparable to that of the fastest known rotating blue horizontal branch (BHB) stars, when allowance is made for differences in radii and moments of inertia. The other six RHB stars have somewhat lower rotation but show a trend to higher values at higher temperatures (lower radii). Comparing our results with those for BHB stars from Kinman et al., we find that the fraction of rapidly rotating RHB stars is somewhat lower than is found among BHB stars. The number of rapidly rotating RHB stars is also smaller than we would have expected from the observed rotation of the RGB stars. We devise two empirical methods to translate our earlier line-broadening results into Vrot sin i for all the RGB and RHB stars they studied. Binning the RGB stars by luminosity, we find that most metal-poor field RGB stars show no detectable sign, on average, of rotation, which is not surprising given the stars' large radii. However, the most luminous stars, with MV

  7. Anomalous scaling in an age-dependent branching model.

    Science.gov (United States)

    Keller-Schmidt, Stephanie; Tuğrul, Murat; Eguíluz, Víctor M; Hernández-García, Emilio; Klemm, Konstantin

    2015-02-01

    We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age τ as τ(-α). Depending on the exponent α, the scaling of tree depth with tree size n displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition (α=1) tree depth grows as (logn)(2). This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus providing a theoretical support for age-dependent speciation and associating it to the occurrence of a critical point. PMID:25768548

  8. Off-take and slug transition at T-junction of vertical-up branch in the horizontal pipe

    International Nuclear Information System (INIS)

    The off-take and the slug transition on air-water interface are experimentally investigated at the T-junction of the horizontal pipe with a vertical upward branch to simulate the loss-of-residual-heat-removal during a mid-loop operation in the Korea standard nuclear power plant. Scaling analysis is performed to scale down the experimental facility to the reference nuclear power plant. Two different diameters of branch pipes are used to verify the scaling laws and their scale effects. Air is used as working gaseous fluid and no water flow exists. Off-take behavior on horizontal stratified and slug flows is visually observed in the horizontal pipe. The experimental data are divided into three categories; onset of liquid entrainment at T-junctions, onset of slug transition in the horizontal pipe, and discharge quality in the branch pipe. It is found out that the scale effect of the branch diameter on the onset of liquid entrainment is small and the existing correlations for it are applicable. Also, the onset of slug transition shows a discrepancy with Taitel-Dukler's correlation and has a strong influence on the discharge quality. New correlations for discharge quality are developed considering the critical dependency of the onset of slugging. (author)

  9. Anomalous scaling in an age-dependent branching model

    OpenAIRE

    Keller-Schmidt, Stephanie; Tugrul, Murat; Víctor M Eguíluz; Hernández-García, Emilio; Klemm, Konstantin

    2015-01-01

    © 2015 American Physical Society. We introduce a one-parametric family of tree growth models, in which branching probabilities decrease with branch age τ as τ-α. Depending on the exponent α, the scaling of tree depth with tree size n displays a transition between the logarithmic scaling of random trees and an algebraic growth. At the transition (α=1) tree depth grows as (logn)2. This anomalous scaling is in good agreement with the trend observed in evolution of biological species, thus provid...

  10. The accretion rate independence of horizontal branch oscillation in XTE J1701-462

    CERN Document Server

    Li, Zhaosheng; Qu, Jinlu; Bu, Qingcui; Wang, Dehua; Xu, Renxin

    2014-01-01

    We study the temporal and energy spectral properties of the unique neutron star low-mass X-ray binary XTE J1701-462. After assuming the HB/NB vertex as a reference position of accretion rate, the horizontal branch oscillation (HBO) of the HB/NB vertex is roughly 50 Hz. It indicates that the HBO is independent with the accretion rate or the source intensity. The spectral analysis shows $R_{\\rm{in}}\\propto\\dot{M}_{\\rm{Disk}}^{2.9\\pm0.09}$ in the HB/NB vertex and $R_{\\rm{in}}\\propto\\dot{M}_{\\rm{Disk}}^{1.7\\pm0.06}$ in the NB/FB vertex, which implies that different accretion rate may be produced in the HB/NB vertex and the NB/FB vertex. The Comptonization component could be fitted by constrained broken power law (CBPL) or nthComp. Different with GX 17+2, the frequencies of HBO positively correlate with the inner disk radius, which contradict with the prediction of Lense-Thirring precession model. XTE J1701-462, both in the Cyg-like phase and in the Sco-like phase, follows a positive correlation between the break ...

  11. Horizontal-branch morphology and multiple stellar populations in the anomalous globular cluster M22

    CERN Document Server

    Marino, A F; Lind, K

    2013-01-01

    M22 is an anomalous globular cluster that hosts two groups of stars with different metallicity and s-element abundance. The star-to-star light-element variations in both groups, with the presence of individual Na-O and C-N anticorrelations, demonstrates that this Milky-Way satellite has experienced a complex star-formation history. We have analysed FLAMES/UVES spectra for seven stars covering a small color interval, on the reddest horizontal-branch (HB) portion of this cluster and investigated possible relations between the chemical composition of a star and its location along the HB. Our chemical abundance analysis takes into account effects introduced by deviations from the local-thermodynamic equilibrium (NLTE effects), that are significant for the measured spectral lines in the atmospheric parameters range spanned by our stars. We find that all the analysed stars are barium-poor and sodium-poor, thus supporting the idea that the position of a star along the HB is strictly related to the chemical compositi...

  12. Mass Loss on the Horizontal Branch an Application to NGC6791

    CERN Document Server

    Yong, H; Yi, S

    2000-01-01

    The presence of a substantial number of hot stars in the extremely metal-rich} open cluster NGC6791 has been a mystery. If these hot stars are in their core helium burning phase, they are significantly bluer (hotter) than predicted by canonical stellar evolution theory. No obvious explanation is available yet. We consider the effects of mass loss during the evolution of horizontal branch (HB) stars as their possible origin. We find that the addition of mass loss causes HB stars to evolve to be hotter and fainter. Mass loss has a more pronounced effect for less massive stars and thus naturally widens the temperature (and color) distribution on the HB. If mass loss rates are higher for more metal-rich stars, this phenomenon would be even more pronounced in the metal-rich populations, such as NGC6791. We find that mass loss on the HB may be a viable method of forming subdwarf B (sdB) stars both in the field and in clusters, especially when the metallicity is high.

  13. Vertical abundance stratification in the blue horizontal branch star HD135485

    CERN Document Server

    Khalack, V R; Bohlender, D A; Wade, G A; Behr, B B

    2007-01-01

    It is commonly believed that the observed overabundances of many chemical species relative to the expected cluster metallicity in blue horizontal branch (BHB) stars appear as a result of atomic diffusion in the photosphere. The slow rotation of BHB stars (with T_eff > 11,500K), typically v sin{i} < 10 km/s, is consistent with this idea. In this work we search for observational evidence of vertical chemical stratification in the atmosphere of HD135485. If this evidence exists, it will demonstrate the importance of atomic diffusion processes in the atmospheres of BHB stars. We undertake an extensive abundance stratification analysis of the atmosphere of HD135485, based on recently acquired high resolution and S/N CFHT ESPaDOnS spectra and a McDonald-CE spectrum. Our numerical simulations show that nitrogen and sulfur reveal signatures of vertical abundance stratification in the stellar atmosphere. It appears that the abundances of these elements increase toward the upper atmosphere. This fact cannot be expla...

  14. The horizontal branch luminosity vs metallicity in M31 globular clusters

    CERN Document Server

    Federici, Luciana; Bellazzini, Michele; Pecci, Flavio Fusi; Galleti, Silvia; Perina, Sibilla

    2012-01-01

    Thanks to the outstanding capabilites of the HST, our current knowledge about the M31 globular clusters (GCs) is similar to our knowledge of the Milky Way GCs in the 1960s-1970s, which set the basis for studying the halo and galaxy formation using these objects as tracers, and established their importance in defining the cosmic distance scale. We intend to derive a new calibration of the M_V(HB)-[Fe/H] relation by exploiting the large photometric database of old GCs in M31 in the HST archive. We collected the BVI data for 48 old GCs in M31 and analysed them by applying the same methods and procedures to all objects. We obtained a set of homogeneous colour-magnitude diagrams (CMDs) that were best-fitted with the fiducial CMD ridge lines of selected Milky Way template GCs. Reddening, metallicity, Horizontal Branch (HB) luminosity and distance were determined self-consistently for each cluster. There are three main results of this study: i) the relation M_V(HB)=(0.25+/-0.02)[Fe/H]+(0.89+/-0.03), which is obtaine...

  15. Vertical stratification of iron in atmospheres of blue horizontal-branch stars

    CERN Document Server

    Khalack, V; Behr, B B

    2010-01-01

    The aim of this study is to search for observational evidence of vertical iron stratification in the atmosphere of fourteen blue horizontal-branch (BHB) stars. We have found from our numerical simulations that five BHB stars: B22, B186 in the globular cluster NGC 288, WF2-820, WF2-2692 in M13 and B203 in M15 show clear signatures of the vertical stratification of iron whose abundance increases toward the lower atmosphere. Two other BHB stars (B334 in M15 and B176 in M92) also show possible iron stratification in their atmosphere. A dependence of the slope of iron stratification on the effective temperature was also discovered. It is found that the vertical stratification of iron is strongest in BHB stars with Teff around 11,500K. The slope of iron abundance decreases as Teff increases and becomes negligible for the BHB stars with Teff= 14,000K. These results support the hypothesis regarding the efficiency of atomic diffusion in the stellar atmospheres of BHB stars with Teff > 11,500K.

  16. RR Lyrae stars and the horizontal branch of NGC 5904 (M5)

    CERN Document Server

    Ferro, A Arellano; Bramich, D M; Giridhar, Sunetra; Ahumada, J A; Muneer, S

    2016-01-01

    We report the distance and [Fe/H] value for the globular cluster NGC 5904 (M5) derived from the Fourier decomposition of the light curves of selected RRab and RRc stars. The aim in doing this was to bring these parameters into the homogeneous scales established by our previous work on numerous other globular clusters, allowing a direct comparison of the horizontal branch luminosity in clusters with a wide range of metallicities. Our CCD photometry of the large variable star population of this cluster is used to discuss light curve peculiarities, like Blazhko modulations, on an individual basis. New Blazhko variables are reported. From the RRab stars we found [Fe/H]$_{\\rm UVES} = -1.335 \\pm 0.003{\\rm(statistical)} \\pm 0.110{\\rm(systematic)}$, and a distance of $7.6\\pm 0.2$ kpc, and from the RRc stars we found [Fe/H]$_{\\rm UVES}$ = $-1.39 \\pm 0.03{\\rm(statistical)} \\pm 0.12{\\rm(systematic)}$ and a distance of $7.5 \\pm 0.3$ kpc. The results for RRab and RRc stars should be considered independent since they come ...

  17. The rms-flux relation of Cyg X-2 in the horizontal branch

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We have investigated the relation between the root mean square(rms) variability and the X-ray flux(rms-flux relation) of the Z source Cyg X-2,and as well the energy dependence based on the Rossi X-ray Timing Explorer(RXTE) observations.We currently focus on the horizontal branch(HB),due to the negative correlation in flux of the soft and the hard X-rays.The rms-flux correlation has energy dependence as follows:positive at hard X-rays(above 10 keV) but negative at soft X-rays(below 10 keV).This provides a feature different from the previous one,and may be suggestive of different origins of X-rays below and above 10 keV.Nevertheless,the overall spectrum can be well fitted with a model consisting of a blackbody and Comptonization components,but the fitting results do not reveal any features around 10 keV that could account for such a change in the rms-flux relation.

  18. Red horizontal branch stars in the Galactic field: A chemical abundance survey

    Directory of Open Access Journals (Sweden)

    Fo B.-Q.

    2013-03-01

    Full Text Available A large sample survey of Galactic red horizontal-branch (RHB stars was conducted to investigate their atmospheric parameters and elemental abundances. High-resolution spectra of 76 Galactic field stars were obtained with the 2.7 m Smith Telescope at McDonald Observatory. Only the color and the parallax were considered during the selection of the field stars. Equivalent width or synthetic spectrum analyses were used in order to determine the relative abundances of the following elements: proton-capture elements C, N, O and Li, alpha-elements Ca and Si, and neutron-capture elements Eu and La. Additionally, 12C/13C isotopic ratios were derived by using the CN features mainly located in the 7995 − 8040 Å spectral region. The evaluation of effective temperatures, surface gravities and 12C/13C isotopic ratios together with evolutionary stages of the candidates revealed that 18 out of 76 stars in our sample are probable RHBs. Including both kinematic and evolutionary status information, we conclude that we have five thick disk and 13 thin disk RHB stars in our sample. Although RHB stars have been regarded as thick disk members of the Galaxy, the low-velocity RHBs with a solar metallicity in our sample suggests the existence of a large number of thin disk RHBs, which cannot be easily explained by standard stellar evolutionary models.

  19. Some remarks on the level of helium enhancement among M3's horizontal-branch stars

    CERN Document Server

    Valcarce, A A R; Alonso-García, J; Ramos, R Contreras; Alves, S

    2016-01-01

    (Abridged) The color and luminosity distribution of horizontal branch (HB) stars in globular clusters are sensitive probes of their original helium abundances. However, recent analyses based on visual and near-ultraviolet (UV) CMDs have provided conflicting results. To clarify the situation, we address the optimum ranges of applicability (in terms of the $T_{eff}$ range covered by the HB stars) for visual and near-UV CMDs, as far as application of this HB $Y$ test goes. We consider both Stromgren and Hubble Space Telescope (HST) bandpasses. Our results indicate that the distributions of HB stars in the y vs (b-y) plane can be a reliable indicator of the He content in cool blue HB (BHB) stars, particularly when a differential comparison between blue and red HB stars is carried out in the range $T_{eff}<8300$K. Conversely, we demonstrate that CMDs using the F336W filter have a much less straightforward interpretation at the cool end of the BHB, as the distributions of HB stars in the F336W vs (F336W-F555W) p...

  20. Effect of occlusion, directionality and age on horizontal localization

    Science.gov (United States)

    Alworth, Lynzee Nicole

    Localization acuity of a given listener is dependent upon the ability discriminate between interaural time and level disparities. Interaural time differences are encoded by low frequency information whereas interaural level differences are encoded by high frequency information. Much research has examined effects of hearing aid microphone technologies and occlusion separately and prior studies have not evaluated age as a factor in localization acuity. Open-fit hearing instruments provide new earmold technologies and varying microphone capabilities; however, these instruments have yet to be evaluated with regard to horizontal localization acuity. Thus, the purpose of this study is to examine the effects of microphone configuration, type of dome in open-fit hearing instruments, and age on the horizontal localization ability of a given listener. Thirty adults participated in this study and were grouped based upon hearing sensitivity and age (young normal hearing, >50 years normal hearing, >50 hearing impaired). Each normal hearing participant completed one localization experiment (unaided/unamplified) where they listened to the stimulus "Baseball" and selected the point of origin. Hearing impaired listeners were fit with the same two receiver-in-the-ear hearing aids and same dome types, thus controlling for microphone technologies, type of dome, and fitting between trials. Hearing impaired listeners completed a total of 7 localization experiments (unaided/unamplified; open dome: omnidirectional, adaptive directional, fixed directional; micromold: omnidirectional, adaptive directional, fixed directional). Overall, results of this study indicate that age significantly affects horizontal localization ability as younger adult listeners with normal hearing made significantly fewer localization errors than older adult listeners with normal hearing. Also, results revealed a significant difference in performance between dome type; however, upon further examination was not

  1. HST/WFPC2 imaging of the dwarf satellites And XI and And XIII: horizontal branch morphology and RR Lyraes

    Science.gov (United States)

    Yang, S.-C.; Sarajedini, A.

    2012-01-01

    We present a study of the stellar populations in two faint M31 dwarf satellites, Andromeda XI and Andromeda XIII. Using archival images from the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope, we characterize the horizontal branch (HB) morphologies and the RR Lyrae (RRL) populations of these two faint dwarf satellites. Our new template light-curve fitting routine [Robust RR Lyrae light curve FITing (RRFIT)] has been used to detect and characterize RRL populations in both galaxies. The mean periods of RRab (RR0) stars in And XI and And XIII are = 0.621 ± 0.026 (error1) ± 0.022 (error2) and 0.648 ± 0.026 (error1) ± 0.022 (error2), respectively, where 'error1' represents the standard error of the mean, while 'error2' is based on our synthetic light-curve simulations. The RRL populations in these galaxies show a lack of RRab stars with high amplitudes [Amp (V) > 1.0 mag] and relatively short periods (? d), yet their period-V-band amplitude [P- Amp (V)] relations track the relation defined by the M31 field halo RRL populations at ˜11 kpc from the centre of M31. The metallicities of the RRab stars are calculated via a relationship between [Fe/H], log Pab and Amp(V). The resultant abundances ([ Fe/H ]And XI=-1.75; [ Fe/H ]And XIII=-1.74) are consistent with the values calculated from the red giant branch slope, indicating that our measurements are not significantly affected by RRL evolutionary away from the zero-age HB. The distance to each galaxy, based on the absolute V magnitudes of the RRab stars, is (m-M)0, V= 24.33 ± 0.05 for And XI and (m-M)0, V= 24.62 ± 0.05 for And XIII. We discuss the origins of And XI and And XIII based on a comparative analysis of the luminosity-metallicity relation of Local Group dwarf galaxies. Based on observations taken with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute.

  2. Horizontal

    Institute of Scientific and Technical Information of China (English)

    ZHONG; Chunping

    2005-01-01

    [1]Wu, H., Bochner technique in differential geometry, Advance in Math. (in Chinese), 1981, 10(1): 57-76.[2]Morrow, J., Kodaira, K., Complex Manifolds, New York: Holt, Rinehart & Winston, 1971.[3]Abate, M., Aikou, T., Patrizio, G., Preface for Complex Finsler Geometry, Cont. Math., Vol. 196, Providence,RI: Amer. Math. Soc., 1996, 97-100.[4]Abate, M., Patrizio, G., Finsler Metrics-A global approach with applications to geometric function theory,Lecture Notes in Mathematics, Vol. 1591, Bedin: Springer-Verlag, 1994.[5]Antonelli, P. L., Lackey, B.(eds.), The Theory of Finslerian Laplacians and Applications, MAIA 459, Dordrecht:Kluwer Academic Publishers, 1998.[6]Bao, D., Lackey, B., A Hodge decomposition theorem for Finsler spaces, C. R. Acad. Sci. Paris, t. 323, Serie 1,1996, 51-56.[7]Munteanu, O., Weitzenbock formulas for horizontal and vertical Laplacians, Houston Journal of Mathematics,2003, 29(4): 889-900.[8]Faran, J. J., The equivalence problem for complex Finsler Hamiltonians, Cont. Math.,Vol. 196, Providence, RI:Amer. Math. Soc., 1996, 133-144.[9]Kobayashi, S., Complex Finsler vector bundles, Cont. Math., Vol. 196, Providence, RI: Amer. Math. Soc.,1996,145-153.[10]Aikou, T., On complex Finsler manifolds, Rep. Fac. Sci. Kagoshima Univ. (Math. Phys. & Chem.), 1991, 24:9-25.

  3. Critical Age-Dependent Branching Markov Processes and their Scaling Limits

    Indian Academy of Sciences (India)

    Krishna B Athreya; Siva R Athreya; Srikanth K Iyer

    2010-06-01

    This paper studies: (i) the long-time behaviour of the empirical distribution of age and normalized position of an age-dependent critical branching Markov process conditioned on non-extinction; and (ii) the super-process limit of a sequence of age-dependent critical branching Brownian motions.

  4. Age-dependent branching processes in random environments

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We consider an age-dependent branching process in random environments. The environments are represented by a stationary and ergodic sequence ξ = (ξ0,ξ1,...) of random variables. Given an environment ξ, the process is a non-homogenous Galton-Watson process, whose particles in n-th generation have a life length distribution G(ξn) on R+, and reproduce independently new particles according to a probability law p(ξn) on N. Let Z(t) be the number of particles alive at time t. We first find a characterization of the conditional probability generating function of Z(t) (given the environment ξ) via a functional equation, and obtain a criterion for almost certain extinction of the process by comparing it with an embedded Galton-Watson process. We then get expressions of the conditional mean EξZ(t) and the global mean EZ(t), and show their exponential growth rates by studying a renewal equation in random environments.

  5. Mapping the Galactic Halo with blue horizontal branch stars from the 2dF quasar redshift survey

    CERN Document Server

    De Propris, Roberto; Mares, Peter J; CTIO,; University, Cornell

    2010-01-01

    We use 666 blue horizontal branch (BHB) stars from the 2Qz redshift survey to map the Galactic halo in four dimensions (position, distance and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and obeys a single power-law density profile of index ~-2.5 in two different directions separated by 150 degrees on the sky. This suggests that the halo is spherical. Our map shows no large kinematically coherent structures (streams, clouds or plumes) and appears homogeneous. However, we find that at least 20% of the stars in the halo reside in substructures and that these substructures are dynamically young. The velocity dispersion profile of the halo appears to increase towards large radii while the stellar velocity distribution is non Gaussian beyond 60 kpc. We argue that the outer halo consists of a multitude of low luminosity overlapping tidal streams from recently accreted objects.

  6. MAPPING THE GALACTIC HALO WITH BLUE HORIZONTAL BRANCH STARS FROM THE TWO-DEGREE FIELD QUASAR REDSHIFT SURVEY

    International Nuclear Information System (INIS)

    We use 666 blue horizontal branch stars from the 2Qz Redshift Survey to map the Galactic halo in four dimensions (position, distance, and velocity). We find that the halo extends to at least 100 kpc in Galactocentric distance, and obeys a single power-law density profile of index ∼-2.5 in two different directions separated by about 1500 on the sky. This suggests that the halo is spherical. Our map shows no large kinematically coherent structures (streams, clouds, or plumes) and appears homogeneous. However, we find that at least 20% of the stars in the halo reside in substructures and that these substructures are dynamically young. The velocity dispersion profile of the halo appears to increase toward large radii while the stellar velocity distribution is non-Gaussian beyond 60 kpc. We argue that the outer halo consists of a multitude of low luminosity overlapping tidal streams from recently accreted objects.

  7. HOT HORIZONTAL BRANCH STARS IN ω CENTAURI: CLUES ABOUT THEIR ORIGIN FROM THE CLUSTER COLOR MAGNITUDE DIAGRAM

    International Nuclear Information System (INIS)

    We investigate a peculiar feature at the hottest, blue end of the horizontal branch of Galactic globular cluster ω Centauri, using the high-precision and nearly complete catalog that has been constructed from a survey taken with the Advanced Camera for Survey on board the Hubble Space Telescope, that covers the inner 10 x 10 arcmin. It is a densely populated clump of stars with an almost vertical structure in the F435W-(F435W-F625W) plane, that we termed 'blue clump'. A comparison with theoretical models leads to the conclusion that this feature must necessarily harbor either hot flasher stars or canonical He-rich stars-progeny of the blue main sequence (MS) subpopulation observed in this cluster-or a mixture of both types, plus possibly a component from the normal-He population hosted by the cluster. A strong constraint coming from theory is that the mass of the objects in the 'blue clump' has to be very finely tuned, with a spread of at most only ∼0.03 Msun. By comparing observed and theoretical star counts along both the H- and He-burning stages we find that at least 15% of the expected He-rich horizontal branch stars are missing from the color-magnitude diagram. This missing population could be the progeny of red giants that failed to ignite central He-burning and have produced He-core white dwarfs (WDs). Our conclusion supports the scenario recently suggested by Calamida et al. for explaining the observed ratio of WDs to MS stars in ω Centauri.

  8. A Detailed Study of Giants and Horizontal Branch Stars in M68: Atmospheric Parameters and Chemical Abundances

    CERN Document Server

    Schaeuble, Marc; Sneden, Chris; Thompson, I B; Shectman, S A; Burley, G S

    2015-01-01

    In this paper, we present a detailed high-resolution spectroscopic study of post main sequence stars in the Globular Cluster M68. Our sample, which covers a range of 4000 K in $T_{eff}$, and 3.5 dex in $log(g)$, is comprised of members from the red giant, red horizontal, and blue horizontal branch, making this the first high-resolution globular cluster study covering such a large evolutionary and parameter space. Initially, atmospheric parameters were determined using photometric as well as spectroscopic methods, both of which resulted in unphysical and unexpected $T_{eff}$, $log(g)$, $\\xi_{t}$, and [Fe/H] combinations. We therefore developed a hybrid approach that addresses most of these problems, and yields atmospheric parameters that agree well with other measurements in the literature. Furthermore, our derived stellar metallicities are consistent across all evolutionary stages, with $\\langle$[Fe/H]$\\rangle$ = $-$2.42 ($\\sigma$ = 0.14) from 25 stars. Chemical abundances obtained using our methodology also ...

  9. Liquid entrainment at an upward oriented vertical branch line from a horizontal pipe

    Science.gov (United States)

    Welter, Kent Byron

    Under simulated accident conditions, tees in the primary coolant loop of a Pressurized Water Reactor (PWR) can deviate from their original design purpose and become separators that effectively remove core heat sink capacity. This method of primary coolant removal is a phenomenological subset of phase separation known as liquid entrainment, whereby liquid is forced from its original path by the inertia of the gas. A comprehensive literature review revealed common deficiencies in previous studies. The Westinghouse AP600 advanced reactor design was chosen to assess the validity of entrainment models. Following a systematic scaling analysis of the prototypic design a model separate effects test was proposed and constructed at Oregon State University. Just under 100 tests were run to fill the deficiencies found in the literature review. New data from the Air-water Test Loop for Advanced Thermal-hydraulic Studies (ATLATS) could not be predicted by published correlations. A new theoretical model for predicting liquid entrainment onset and steady state entrainment was developed. Comparison with all available data shows a marked improvement for predicting the mass flow rate out the vertical branch.

  10. The Stellar Populations of the Carina Dwarf Spheroidal Galaxy: I. a New Color-Magnitude Diagram for the Giant and Horizontal Branches

    OpenAIRE

    Smecker-Hane, T. A.; Stetson, P. B.; Hesser, J. E.; Lehnert, M. D.

    1994-01-01

    We report on the first in a series of studies of the Carina dwarf spheroidal galaxy, a nearby satellite of our Galaxy. Our two major results are: 1) precise BI photometry ($\\sigma_{B-I} \\simlt 0.05$ for $V \\simlt 22$) for 11,489 stars in the Carina field, and 2) the detection of two, morphologically distinct, horizontal branches, which confirms that star formation in Carina occurred in two well-separated episodes. The old horizontal branch and RR Lyrae instability strip belong to a > 10 Gyr s...

  11. Age, Gender, and Training in Children's Performance of Piaget's Horizontality Task.

    Science.gov (United States)

    Parameswaran, Gowri

    2003-01-01

    Presents a study in which children (n=600), ages five to nine, completed Jean Piaget's horizontality task using a square water bottle. Finds a significant sex difference in the pretest performance of the horizontality task beginning with eight year olds. Includes references. (CMK)

  12. Correlations in Horizontal Branch Oscillations and Break Components in XTE J1701-462 and GX 17+2

    CERN Document Server

    Bu, Qing-cui; Li, Zhao-sheng; Qu, Jin-lu; Belloni, T M; Zhang, Liang

    2014-01-01

    We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent "Sco-like" Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary which separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, although it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studi...

  13. Chemical abundances of the metal-poor horizontal-branch stars CS 22186-005 and CS 30344-033

    CERN Document Server

    Caliskan, S; Bonifacio, P; Christlieb, N; Monaco, L; Beers, T C; Albayrak, B; Sbordone, L

    2014-01-01

    We report on a chemical-abundance analysis of two very metal-poor horizontal-branch stars in the Milky Way halo: CS 22186-005 ([Fe/H]=-2.70) and CS 30344-033 ([Fe/H]=-2.90). The analysis is based on high-resolution spectra obtained at ESO, with the spectrographs HARPS at the 3.6 m telescope, and UVES at the VLT. We adopted one-dimensional, plane-parallel model atmospheres assuming local thermodynamic equilibrium. We derived elemental abundances for 13 elements for CS 22186-005 and 14 elements for CS 30344-033. This study is the first abundance analysis of CS 30344-033. CS 22186-005 has been analyzed previously, but we report here the first measurement of nickel (Ni; Z = 28) for this star, based on twenty-two NiI lines ([Ni/Fe]=-0.21$\\pm$0.02); the measurement is significantly below the mean found for most metal-poor stars. Differences of up to 0.5 dex in [Ni/Fe] ratios were determined by different authors for the same type of stars in the literature, which means that it is not yet possible to conclude that th...

  14. KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS

    International Nuclear Information System (INIS)

    Here, we present a kinematic study of the Galactic halo out to a radius of ∼60 kpc, using 4664 blue horizontal branch stars selected from the SDSS/SEGUE survey to determine key dynamical properties. Using a maximum likelihood analysis, we determine the velocity dispersion profiles in spherical coordinates (σr, σθ, σφ) and the anisotropy profile (β). The radial velocity dispersion profile (σr) is measured out to a galactocentric radius of r ∼ 60 kpc, but due to the lack of proper-motion information, σθ, σφ, and β could only be derived directly out to r ∼ 25 kpc. From a starting value of β ≈ 0.5 in the inner parts (9 circ) of the Galaxy out to r ∼ 25 kpc. The mass of the Galaxy within r ∼11 M☉, and with a three-component fit to vcirc(r), we determine the virial mass of the Milky Way dark matter halo to be Mvir = 0.9+0.4–0.3 × 1012 M☉ (Rvir = 249+34–31 kpc).

  15. On the Magnetospheric Beat-Frequency and Lense-Thirring Interpretations of the Horizontal Branch Oscillation in the Z Sources

    CERN Document Server

    Psaltis, D; Homan, J; Jonker, P G; Van der Klis, M; Miller, M C; Lamb, F K; Kuulkers, E; Van Paradijs, J; Lewin, W H G; Psaltis, Dimitrios; Wijnands, Rudy; Homan, Jeroen; Jonker, Peter G.; Klis, Michiel van der; Lamb, Frederick K.; Kuulkers, Erik; Paradijs, Jan van; Lewin, Walter H.G.

    1999-01-01

    We study the horizontal branch oscillations (HBO) and the two simultaneous kilohertz QPOs comparing their properties in five Z sources with the predictions of the magnetospheric beat-frequency and Lense-Thirring precession models. We find that the variation of the HBO frequency with accretion rate predicted by the magnetospheric beat-frequency model for a purely dipolar stellar magnetic field and a radiation-pressure-dominated inner accretion disk agrees well with the observed variation. This model implies that the neutron stars in the Z sources are near magnetic spin equilibrium, that their magnetic field strengths are ~10^9-10^10 G, and that the critical fastness parameter for these sources is >0.8. If the frequency of the upper kilohertz QPO is an orbital frequency in the accretion disk, the magnetospheric beat-frequency model requires that a small fraction of the gas in the disk does not couple strongly to the stellar magnetic field at 3-4 stellar radii but instead drifts slowly inward in nearly circular ...

  16. Pulsating hot O subdwarfs in Omega Cen: mapping a unique instability strip on the Extreme Horizontal Branch

    CERN Document Server

    Randall, S K; Fontaine, G; Monelli, M; Bono, G; Alonso, M L; Van Grootel, V; Brassard, P; Chayer, P; Catelan, M; Littlefair, S; Dhillon, V S; Marsh, T R

    2016-01-01

    We present an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in omega Cen. The observations performed consist of nearly 100 hours of time-series photometry, as well as low-resolution spectroscopy. We obtained photometry for some 300 EHB stars. Based on the spectroscopy, we derive reliable values of log g, Teff and log(N(He)/N(H)) for 38 targets, as well as estimates of the effective temperature for another nine targets. The survey uncovered a total of five rapid variables with multi-periodic oscillations between 85 and 125 s. Spectroscopically, they form a homogeneous group of hydrogen-rich subdwarf O stars clustered between 48,000 and 54,000 K. For each of the variables we are able to measure between two and three significant pulsations believed to constitute independent harmonic oscillations. In addition to the rapid variables, we found an EHB star with an apparently periodic luminosity variation of ~2700 s, which we tentatively suggest may be caused by ellipsoidal variatio...

  17. The visitor from an ancient galaxy: A planetary companion around an old, metal-poor red horizontal branch star

    CERN Document Server

    Klement, Rainer J; Henning, Thomas; Rix, Hans-Walter; Rochau, Boyke; Rodmann, Jens; Schulze-Hartung, Tim; Heidelberg, MPIA; ESTEC,

    2010-01-01

    We report the detection of a planetary companion around HIP 13044, a metal-poor red horizontal branch star belonging to a stellar halo stream that results from the disruption of an ancient Milky Way satellite galaxy. The detection is based on radial velocity observations with FEROS at the 2.2-m MPG/ESO telescope. The periodic radial velocity variation of P=16.2 days can be distinguished from the periods of the stellar activity indicators. We computed a minimum planetary mass of 1.25 Jupiter masses and an orbital semimajor axis of 0.116 AU for the planet. This discovery is unique in three aspects: First, it is the first planet detection around a star with a metallicity much lower than few percent of the solar value; second, the planet host star resides in a stellar evolutionary stage that is still unexplored in the exoplanet surveys; third, the planetary system HIP 13044 most likely has an extragalactic origin in a disrupted former satellite of the Milky Way.

  18. CORRELATIONS IN HORIZONTAL BRANCH OSCILLATIONS AND BREAK COMPONENTS IN XTE J1701-462 AND GX 17+2

    International Nuclear Information System (INIS)

    We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent ''Sco-like'' Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused by the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rmsbreak-rmsHBO diagram

  19. CORRELATIONS IN HORIZONTAL BRANCH OSCILLATIONS AND BREAK COMPONENTS IN XTE J1701-462 AND GX 17+2

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Qing-cui; Chen, Li; Zhang, Liang [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Li, Zhao-sheng [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Qu, Jin-lu [Laboratory for Particle Astrophysics, CAS, Beijing 100049 (China); Belloni, T. M., E-mail: buqc@mail.bnu.edu.cn, E-mail: chenli@bnu.edu.cn, E-mail: qujl@ihep.ac.cn, E-mail: tomaso.belloni@brera.inaf.it [INAF-Osservatorio Astronomico di Brera, Via E, Bianchi 46, I-23807 Merate (Italy)

    2015-01-20

    We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent ''Sco-like'' Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused by the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rms{sub break}-rms{sub HBO} diagram.

  20. A semi-empirical approach for predicting two-phase flow discharge through branches of various orientations connected to a horizontal main pipe

    International Nuclear Information System (INIS)

    The subdivision of two-phase flow in branching conduits consisting of a large horizontal main pipe with upward, downward, or lateral branches of reduced diameter is of great interest in various technological fields. For example, these conduits are important in light-water nuclear reactors (LWRs) in the case of a small break loss-of-coolant accident (SBLOCA) in a leg of the reactor's primary coolant loops, as well as for breaks or valve malfunctions in a large pipeline. In these kinds of circumstances, the relevant phenomenology often involves phase stratification coupled with possible liquid entrainment or gas pool-through phenomena. Therefore, these phenomena were studied in depth to evaluate the pressure drop across conduit elements resulting from the redistribution of flow phases and the discharged mass among them. In the past, several experiments have been performed along with studies in flow modelling. As a result, several formulae and models for branch exit quality and consequent discharge mass flow rate predictions have been proposed. In recent years, we have been engaged in extensive research on this subject, resulting in a new semi-empirical formulation to express branch exit quality in terms of the physical processes taking place in the conduits, the operating parameters and the branch geometry. In this paper, we applied these correlations to representative sets of experiments previously reported in the literature, comprising a wide range of branch-to-main-pipe diameter ratios and operating pressures, which proved our formulation to be very accurate.

  1. Pulsating hot O subdwarfs in ω Centauri: mapping a unique instability strip on the extreme horizontal branch

    Science.gov (United States)

    Randall, S. K.; Calamida, A.; Fontaine, G.; Monelli, M.; Bono, G.; Alonso, M. L.; Van Grootel, V.; Brassard, P.; Chayer, P.; Catelan, M.; Littlefair, S.; Dhillon, V. S.; Marsh, T. R.

    2016-05-01

    We present the results of an extensive survey for rapid pulsators among Extreme Horizontal Branch (EHB) stars in ω Cen. The observations performed consist of nearly 100 h of time-series photometry for several off-centre fields of the cluster, as well as low-resolution spectroscopy for a partially overlapping sample. We obtained photometry for some 300 EHB stars, for around half of which we are able to recover light curves of sufficient quality to either detect or place meaningful non-detection limits for rapid pulsations. Based on the spectroscopy, we derive reliable values of log g, Teff and log N(He) /N(H) for 38 targets, as well as good estimates of the effective temperature for another nine targets, whose spectra are slightly polluted by a close neighbour in the image. The survey uncovered a total of five rapid variables with multi-periodic oscillations between 85 and 125 s. Spectroscopically, they form a homogeneous group of hydrogen-rich subdwarf O stars clustered between 48 000 and 54 000 K. For each of the variables we are able to measure between two and three significant pulsations believed to constitute independent harmonic oscillations. However, the interpretation of the Fourier spectra is not straightforward due to significant fine structure attributed to strong amplitude variations. In addition to the rapid variables, we found an EHB star with an apparently periodic luminosity variation of ~2700 s, which we tentatively suggest may be caused by ellipsoidal variations in a close binary. Using the overlapping photometry and spectroscopy sample we are able to map an empirical ω Cen instability strip in log g - Teff space. This can be directly compared to the pulsation driving predicted from the Montréal "second-generation" models regularly used to interpret the pulsations in hot B subdwarfs. Extending the parameter range of these models to higher temperatures, we find that the region where p-mode excitation occurs is in fact bifurcated, and the well

  2. Fluctuation limit theorems for age-dependent critical binary branching systems

    Directory of Open Access Journals (Sweden)

    Murillo-Salas Antonio

    2011-03-01

    Full Text Available We consider an age-dependent branching particle system in ℝd, where the particles are subject to α-stable migration (0 < α ≤ 2, critical binary branching, and general (non-arithmetic lifetimes distribution. The population starts off from a Poisson random field in ℝd with Lebesgue intensity. We prove functional central limit theorems and strong laws of large numbers under two rescalings: high particle density, and a space-time rescaling that preserves the migration distribution. Properties of the limit processes such as Markov property, almost sure continuity of paths and generalized Langevin equation, are also investigated.

  3. The ultraviolet lines of carbon, nitrogen, and oxygen in the IUE spectrum of the field horizontal-branch A star HD 109995

    Science.gov (United States)

    Leckrone, David S.; Adelman, Saul J.

    1986-01-01

    Photospheric abundances of C, N and O of an evolved halo Population 2 star, the field horizontal-branch star HD 109995, based on observations of ultraviolet resonance or low excitation lines are presented. The logarithmic abundance ratio with respect to the Sun O/Fe = +1.5 is substantially higher than previously determined values for Pop. 2 red giants or RR Lyrae stars, but agrees well with a derived value from the OI infrared triplet. This may be direct evidence of Tinsley's (1979) scenario of localized sharply rising interstellar oxygen abundances immediately following bursts of massive star formation. Star HD 109995 may have formed from such highly oxygen-enriched material prior to its dilution by gas with the pre-burst composition. The ratio C/N = -1.3 may reflect the composition of material from which the star formed or CN processing within the star during its evolution.

  4. Relation between the quasi-periodic oscillations and the low-frequency noise of GX 5-1 in the horizontal branch

    Science.gov (United States)

    Mitsuda, Kazuhisa; Dotani, Tadayasu; Yoshida, Atsumasa; Vaughan, Brian; Norris, Jay P.

    1991-01-01

    Ginga observations of quasi-periodic oscillations (QPOs) and the low-frequency noise (LFN) from GX 5-1 in its horizontal-branch spectral state are presented. Power spectral fits were attempted using model functions based on simple oscillating shot models. A clear second-harmonic peak of QPO was detected. Variations in the powers of QPO and LFN on timescales of 8-256 s were also studied. These variations were significant for all of the timescales studied, and were uncorrelated with each other on timescales shorter than a few tens of seconds, and correlated on longer timescales. From simulations based on a simple shot model, it was found that the variation amplitude and the lack of correlation on short timescales are not inconsistent with the oscillating shot models. A more complex model is necessary to fully explain the observed properties.

  5. The tight subgiant branch of the intermediate-age star cluster NGC 411 implies a single-aged stellar population

    CERN Document Server

    Li, Chengyuan; Bastian, Nathan; Deng, Licai; Niederhofer, Florian; Zhang, Chaoli

    2016-01-01

    The presence of extended main-sequence turn-off (eMSTO) regions in intermediate-age star clusters in the Large and Small Magellanic Clouds is often interpreted as resulting from extended star-formation histories (SFHs), lasting $\\geq$ 300 Myr. This strongly conflicts with the traditional view of the dominant star-formation mode in stellar clusters, which are thought of as single-aged stellar populations. Here we present a test of this interpretation by exploring the morphology of the subgiant branch (SGB) of NGC 411, which hosts possibly the most extended eMSTO among all known intermediate-age star clusters. We show that the width of the NGC 411 SGB favours the single-aged stellar population interpretation and rules out an extended SFH. In addition, when considering the red clump (RC) morphology and adopting the unproven premise that the widths of all features in the colour--magnitude diagram are determined by an underlying range in ages, we find that the SFH implied is still very close to that resulting from...

  6. The Abundances of Neutron-capture Species in the Very Metal-poor Globular Cluster M15: A Uniform Analysis of Red Giant Branch and Red Horizontal Branch Stars

    Science.gov (United States)

    Sobeck, Jennifer S.; Kraft, Robert P.; Sneden, Christopher; Preston, George W.; Cowan, John J.; Smith, Graeme H.; Thompson, Ian B.; Shectman, Stephen A.; Burley, Gregory S.

    2011-06-01

    The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and red horizontal branch (RHB) stars. No attempt has been made to perform a single, self-consistent analysis of these stars, which exhibit a wide range in atmospheric parameters. In the current effort, a new comparative abundance derivation is presented for three RGB and six RHB members of the cluster. The analysis employs an updated version of the line transfer code MOOG, which now appropriately treats coherent, isotropic scattering. The apparent discrepancy in the previously reported values for the metallicity of M15 RGB and RHB stars is addressed and a resolute disparity of Δ(RHB - RGB) ≈ 0.1 dex in the iron abundance was found. The anti-correlative behavior of the light neutron-capture elements (Sr, Y, Zr) is clearly demonstrated with both Ba and Eu, standard markers of the s- and r-process, respectively. No conclusive detection of Pb was made in the RGB targets. Consequently for the M15 cluster, this suggests that the main component of the s-process has made a negligible contribution to those elements normally dominated by this process in solar system material. Additionally for the M15 sample, a large Eu abundance spread is confirmed, which is comparable to that of the halo field at the same metallicity. These abundance results are considered in the discussion of the chemical inhomogeneity and nucleosynthetic history of M15.

  7. THE ABUNDANCES OF NEUTRON-CAPTURE SPECIES IN THE VERY METAL-POOR GLOBULAR CLUSTER M15: A UNIFORM ANALYSIS OF RED GIANT BRANCH AND RED HORIZONTAL BRANCH STARS

    International Nuclear Information System (INIS)

    The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and red horizontal branch (RHB) stars. No attempt has been made to perform a single, self-consistent analysis of these stars, which exhibit a wide range in atmospheric parameters. In the current effort, a new comparative abundance derivation is presented for three RGB and six RHB members of the cluster. The analysis employs an updated version of the line transfer code MOOG, which now appropriately treats coherent, isotropic scattering. The apparent discrepancy in the previously reported values for the metallicity of M15 RGB and RHB stars is addressed and a resolute disparity of Δ(RHB - RGB) ∼ 0.1 dex in the iron abundance was found. The anti-correlative behavior of the light neutron-capture elements (Sr, Y, Zr) is clearly demonstrated with both Ba and Eu, standard markers of the s- and r-process, respectively. No conclusive detection of Pb was made in the RGB targets. Consequently for the M15 cluster, this suggests that the main component of the s-process has made a negligible contribution to those elements normally dominated by this process in solar system material. Additionally for the M15 sample, a large Eu abundance spread is confirmed, which is comparable to that of the halo field at the same metallicity. These abundance results are considered in the discussion of the chemical inhomogeneity and nucleosynthetic history of M15.

  8. The tight subgiant branch of the intermediate-age star cluster NGC 411 implies a single-aged stellar population

    Science.gov (United States)

    Li, C.; de Grijs, R.; Bastian, N.; Deng, L.; Niederhofer, F.; Zhang, C.

    2016-09-01

    The presence of extended main-sequence turn-off (eMSTO) regions in intermediate-age star clusters in the Large and Small Magellanic Clouds is often interpreted as resulting from extended star formation histories (SFHs), lasting ≥300 Myr. This strongly conflicts with the traditional view of the dominant star formation mode in stellar clusters, which are thought of as single-aged stellar populations. Here we present a test of this interpretation by exploring the morphology of the subgiant branch (SGB) of NGC 411, which hosts possibly the most extended eMSTO among all known intermediate-age star clusters. We show that the width of the NGC 411 SGB favours the single-aged stellar population interpretation and rules out an extended SFH. In addition, when considering the red clump (RC) morphology and adopting the unproven premise that the widths of all features in the colour-magnitude diagram are determined by an underlying range in ages, we find that the SFH implied is still very close to that resulting from a single-aged stellar population, with a minor fraction of stars scattering to younger ages compared with the bulk of the population. The SFHs derived from the SGB and RC are both inconsistent with the SFH derived from the eMSTO region. NGC 411 has a very low escape velocity and it has unlikely undergone significant mass-loss at an early stage, thus indicating that it may lack the capacity to capture most of its initial, expelled gas from stellar evolutionary processes, a condition often required for extended SFHs to take root.

  9. The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. VII. Implications from the Nearly Universal Nature of Horizontal Branch Discontinuities

    CERN Document Server

    Brown, Thomas M; D'Antona, Francesca; Salaris, Maurizio; Milone, Antonino P; Dalessandro, Emanuele; Piotto, Giampaolo; Renzini, Alvio; Sweigart, Allen V; Bellini, Andrea; Ortolani, Sergio; Sarajedini, Ata; Aparicio, Antonio; Bedin, Luigi R; Anderson, Jay; Pietrinferni, Adriano; Nardiello, Domenico

    2016-01-01

    The UV-initiative Hubble Space Telescope Treasury survey of Galactic globular clusters provides a new window into the phenomena that shape the morphological features of the horizontal branch (HB). Using this large and homogeneous catalog of UV and blue photometry, we demonstrate that the HB exhibits discontinuities that are remarkably consistent in color (effective temperature). This consistency is apparent even among some of the most massive clusters hosting multiple distinct sub-populations (such as NGC 2808, omega Cen, and NGC 6715), demonstrating that these phenomena are primarily driven by atmospheric physics that is independent of the underlying population properties. However, inconsistencies arise in the metal-rich clusters NGC 6388 and NGC 6441, where the discontinuity within the blue HB (BHB) distribution shifts ~1,000 K to 2,000 K hotter. We demonstrate that this shift is likely due to a large helium enhancement in the BHB stars of these clusters, which in turn affects the surface convection and evo...

  10. AMPLITUDE FINE STRUCTURE IN THE CEPHEID P-L RELATION. I. AMPLITUDE DISTRIBUTION ACROSS THE RR LYRAE INSTABILITY STRIP MAPPED USING THE ACCESSIBILITY RESTRICTION IMPOSED BY THE HORIZONTAL BRANCH

    International Nuclear Information System (INIS)

    The largest amplitude light curves for both RR Lyrae (RRL) variables and classical Cepheids with periods less than 10 days and greater than 20 days occur at the blue edge of the respective instability strips. It is shown that the equation for the decrease in amplitude with penetration into the strip from the blue edge, and hence the amplitude fine structure within the strip, is the same for RRL and the Cepheids despite their metallicity differences. However, the manifestation of this identity is different between the two classes of variables because the sampling of the RRL strip is restricted by the discrete strip positions of the horizontal branch, a restriction that is absent for the Cepheids in stellar aggregates with a variety of ages. To show the similarity of the strip amplitude fine structure for RRL and Cepheids, we make a grid of lines of constant amplitude in the H-R diagram of the strip using amplitude data for classical Cepheids in the Galaxy, LMC, and SMC. The model implicit in the grid, that also contains lines of constant period, is used to predict the correlations between period, amplitude, and color for the two Oosterhoff RRL groups in globular clusters. The good agreement of the predictions with the observations using the classical Cepheid amplitude fine structure also for the RRL shows one aspect of the unity of the pulsation processes between the two classes of variables.

  11. The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. VII. Implications from the Nearly Universal Nature of Horizontal Branch Discontinuities

    Science.gov (United States)

    Brown, T. M.; Cassisi, S.; D’Antona, F.; Salaris, M.; Milone, A. P.; Dalessandro, E.; Piotto, G.; Renzini, A.; Sweigart, A. V.; Bellini, A.; Ortolani, S.; Sarajedini, A.; Aparicio, A.; Bedin, L. R.; Anderson, J.; Pietrinferni, A.; Nardiello, D.

    2016-05-01

    The UV-initiative Hubble Space Telescope Treasury survey of Galactic globular clusters provides a new window into the phenomena that shape the morphological features of the horizontal branch (HB). Using this large and homogeneous catalog of UV and blue photometry, we demonstrate that the HB exhibits discontinuities that are remarkably consistent in color (effective temperature). This consistency is apparent even among some of the most massive clusters hosting multiple distinct sub-populations (such as NGC 2808, ω Cen, and NGC 6715), demonstrating that these phenomena are primarily driven by atmospheric physics that is independent of the underlying population properties. However, inconsistencies arise in the metal-rich clusters NGC 6388 and NGC 6441, where the discontinuity within the blue HB (BHB) distribution shifts ∼1000–2000 K hotter. We demonstrate that this shift is likely due to a large helium enhancement in the BHB stars of these clusters, which in turn affects the surface convection and evolution of such stars. Our survey also increases the number of Galactic globular clusters known to host blue-hook stars (also known as late hot flashers) from 6 to 23 clusters. These clusters are biased toward the bright end of the globular cluster luminosity function, confirming that blue-hook stars tend to form in the most massive clusters with significant self-enrichment. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-13297.

  12. Age-related Hearing Loss and Ear Morphology Affect Vertical but not Horizontal Sound-Localization Performance

    OpenAIRE

    Otte, Rik J.; Agterberg, Martijn J. H.; van Wanrooij, Marc M.; Snik, Ad F. M.; van Opstal, A. John

    2013-01-01

    Several studies have attributed deterioration of sound localization in the horizontal (azimuth) and vertical (elevation) planes to an age-related decline in binaural processing and high-frequency hearing loss (HFHL). The latter might underlie decreased elevation performance of older adults. However, as the pinnae keep growing throughout life, we hypothesized that larger ears might enable older adults to localize sounds in elevation on the basis of lower frequencies, thus (partially) compensat...

  13. Effect of Caenorhabditis elegans age and genotype on horizontal gene transfer in intestinal bacteria

    OpenAIRE

    Portal-Celhay, Cynthia; Nehrke, Keith; Martin J. Blaser

    2013-01-01

    Horizontal gene transfer (HGT) between bacteria occurs in the intestinal tract of their animal hosts and facilitates both virulence and antibiotic resistance. A model in which both the pathogen and the host are genetically tractable facilitates developing insight into mechanistic processes enabling or restricting the transfer of antibiotic resistance genes. Here we develop an in vivo experimental system to study HGT in bacteria using Caenorhabditis elegans as a model host. Using a thermosensi...

  14. Analemmatic and Horizontal Sundials of the Bronze Age (Northern Black Sea Coast)

    CERN Document Server

    Vodolazhskaya, Larisa

    2013-01-01

    The paper presents the results of a study of unique plate with images of Srubna burial of tumuli group Popov Yar-2 (Ukraine) and plate of Srubna burial of tumulus field Tavriya-1 (Russia). A distinctive feature of the images is the orderliness and symmetry of the composition, as well as the location of elliptical cupped depressions. With the help of mathematical and astronomical methods we prove in this paper that the plates with the images are the ancient sundials. At the Popov Yar-2 plate located two sundials, which worked at the same time: the analemmatic sundial and the horizontal sundial with two gnomons and the linear scale. At the Tavriya-1 plate located analemmatic sundial. On the basis of the reconstruction of the linear parameters of the gnomon of both Popov Yar-2 plate sundials and given the scale value of horizontal sundial, in the article that the potential indirect impact protoscientific knowledge of ancient Egypt to the Srubna population in the Northern Black Sea coast. Srubna burial, plate, we...

  15. Diallel crossing in Pinus cembra: IV. age trends in genetic parameters and genetic gain for growth and branching traits

    Directory of Open Access Journals (Sweden)

    Ioan Blada

    2013-12-01

    Full Text Available This paper reports results from a complete 10 x 10 diallel carried out in a natural population of Swiss stone pine (Pinus cembra L. from the southern Carpathian Mountains. At age six, after nursery testing, the material was field planted on one site, using a completely randomized block design with 100 families, four replicates and 15 tree row-plots per replication, spaced 2.5 x 2.5m. Total and annual height growth, root collar diameter, number of branches per whorl and survival were assessed at successive ages between ages eight and 14 after seed. In addition, several traits that were assessed during the nursery test were used in correlation and some other analyses. Plot means of the measured traits were analyzed using the general least-squares method by means of the computer DIALL programme prepared by Schaffer and Usanis (1969. Across the field testing periods, significant (p<0.05 and highly significant (p<0.01; p<0.001 differences occurred in total height growth and root collar diameter for general and specific combining ability as well for maternalinteraction effects. These results suggest that the traits are controlled by nuclear (additive and non-additive and by nuclear x extra-nuclear gene interactions. In an ascendant trend, the additive variance, as a percent of the total genetic variance, ranged from 35% at age eight to 66% at age 14 for total height growth, while that for root collar diameter trend varied less between 16% and 34%. In a descendant trend, the dominance ratios s2SCA/ s2GCA for total height growth ranged from 0.9 at age eight to 0.3 at age 14, suggesting that the additive variance should be used in the breeding programme. Parents with significant general combining effects for all but one trait were found. For total height growth, the narrow-sense family mean heritability estimates varied in an ascendant trend between 0.45 and 0.65 while the narrow- sense individual tree heritability varied irregularly from year to year

  16. Diallel crossing in Pinus cembra : IV. Age trends in genetic parameters and genetic gain for growth and branching traits

    Directory of Open Access Journals (Sweden)

    Ioan Blada

    2008-09-01

    Full Text Available This paper reports results from a complete 10 x 10 diallel carried out in a natural population of Swiss stone pine (Pinus cembra L. from the southern Carpathian Mountains. At age six, after nursery testing, the material was field planted on one site, using a completely randomized block design with 100 families, fourreplicates and 15 tree row-plots per replication, spaced 2.5 x 2.5m. Total and annual height growth, root collar diameter, number of branches per whorl and survival were assessed at successive ages between ages eight and 14 after seed. In addition, severaltraits that were assessed during the nursery test were used in correlation and some other analysis. Plot means of the measured traits were analyzed using the general least-squares method by means of the computer DIALL programme prepared by Schaffer and Usanis (1969. Across the field testing periods, significant (p<0.05 andhighly significant (p<0.01; p<0.001 differences occurred in total height growth and root collar diameter for general and specific combining ability as well for maternalinteraction effects. These results suggest that the traits are controlled by nuclear(additive and non-additive and by nuclear x extra-nuclear gene interactions. In an ascendant trend, the additive variance, as a percent of the total genetic variance, ranged from 35% at age eight to 66% at age 14 for total height growth, while that for root collar diameter trend varied less between 16% and 34%. In a descendant trend,the dominance ratios σ2SCA/ σ2GCA for total height growth ranged from 0.9 at age eight to 0.3 at age 14, suggesting that the additive variance should be used in the breeding programme. Parents with significant general combining effects for all but one trait were found. For total height growth, the narrow-sense family mean heritability estimates varied in an ascendant trend between 0.45 and 0.65 while the narrow-sense individual tree heritability varied irregularly from year to year

  17. The age of the oldest globular clusters

    CERN Document Server

    Salaris, M; Weiss, A

    1996-01-01

    The age of three of the oldest clusters -- M15, M68, M92 -- has been redetermined. We use the latest EOS and opacity data available for calculating both isochrones and zero age horizontal branches and employ the brightness difference between turn-off and horizontal branch to determine the cluster age. Our best ages for all three clusters are about 13 Gyr, and even smaller ages are possible. Our results help to reconcile cluster ages with recent results on the age of the universe determined from the Hubble constant.

  18. THE INSIDIOUS BOOSTING OF THERMALLY PULSING ASYMPTOTIC GIANT BRANCH STARS IN INTERMEDIATE-AGE MAGELLANIC CLOUD CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Girardi, Léo [Osservatorio Astronomico di Padova-INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Marigo, Paola [Dipartimento di Fisica e Astronomia Galileo Galilei, Università di Padova, Vicolo dell' Osservatorio 3, I-35122 Padova (Italy); Bressan, Alessandro [SISSA, via Bonomea 365, I-34136 Trieste (Italy); Rosenfield, Philip [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2013-11-10

    In the recent controversy about the role of thermally pulsing asymptotic giant branch (TP-AGB) stars in evolutionary population synthesis (EPS) models of galaxies, one particular aspect is puzzling: TP-AGB models aimed at reproducing the lifetimes and integrated fluxes of the TP-AGB phase in Magellanic Cloud (MC) clusters, when incorporated into EPS models, are found to overestimate, to various extents, the TP-AGB contribution in resolved star counts and integrated spectra of galaxies. In this paper, we call attention to a particular evolutionary aspect, linked to the physics of stellar interiors, that in all probability is the main cause of this conundrum. As soon as stellar populations intercept the ages at which red giant branch stars first appear, a sudden and abrupt change in the lifetime of the core He-burning phase causes a temporary 'boost' in the production rate of subsequent evolutionary phases, including the TP-AGB. For a timespan of about 0.1 Gyr, triple TP-AGB branches develop at slightly different initial masses, causing their frequency and contribution to the integrated luminosity of the stellar population to increase by a factor of ∼2. The boost occurs for turn-off masses of ∼1.75 M{sub ☉}, just in the proximity of the expected peak in the TP-AGB lifetimes (for MC metallicities), and for ages of ∼1.6 Gyr. Coincidently, this relatively narrow age interval happens to contain the few very massive MC clusters that host most of the TP-AGB stars used to constrain stellar evolution and EPS models. This concomitance makes the AGB-boosting particularly insidious in the context of present EPS models. As we discuss in this paper, the identification of this evolutionary effect brings about three main consequences. First, we claim that present estimates of the TP-AGB contribution to the integrated light of galaxies derived from MC clusters are biased toward too large values. Second, the relative TP-AGB contribution of single-burst populations

  19. Adiabatic Mass Loss in Binary Stars. II. From Zero-Age Main Sequence to the Base of the Giant Branch

    CERN Document Server

    Ge, Hongwei; Chen, Xuefei; Han, Zhanwen

    2015-01-01

    In the limit of extremely rapid mass transfer, the response of a donor star in an interacting binary becomes asymptotically one of adiabatic expansion. We survey here adiabatic mass loss from Population I stars of mass 0.10 Msun to 100 Msun from the zero age main sequence to the base of the giant branch, or to central hydrogen exhaustion for lower main sequence stars. For intermediate- and high-mass stars, dynamical mass transfer is preceded by an extended phase of thermal time scale mass transfer as the star is stripped of most of its envelope mass. The critical mass ratio qad above which this delayed dynamical instability occurs increases with advancing evolutionary age of the donor star, by ever-increasing factors for more massive donors. Most intermediate- or high-mass binaries with nondegenerate accretors probably evolve into contact before manifesting this instability. As they approach the base of the giant branch, however, and begin developing a convective envelope, qad plummets dramatically among inte...

  20. Age-related differences between thinning of horizontal and vertical trabeculae in human lumbar bone as assessed by a new computerized method

    DEFF Research Database (Denmark)

    Thomsen, J.S.; Ebbesen, E.N.; Mosekilde, Li.

    2002-01-01

    To investigate whether vertical trabeculae undergo compensatory thickening with age in the human vertebral body, a new computerized method was developed that is able to distinguish between horizontal and vertical trabeculae on normal histological sections. Study subjects included 48 individuals (24...... trabeculae was developed and implemented in a computer program. The parallel-plate model was modified so that it was able to determine trabecular thickness, number, and separation (Tb.Th, Tb.N, and Tb.Sp) for horizontal and vertical trabeculae separately. The histomorphometric parameters were measured in...... tissue. This method has been applied on frontal vertebral sections. Trabecular bone thickness measured with the parallel-plate model showed that the thickness of horizontal trabeculae decreases significantly with age, whereas the thickness of vertical trabeculae did not decrease significantly with age...

  1. The Morphology of the Sub-Giant Branch and Red Clump Reveal No Sign of Age Spreads in Intermediate Age Clusters

    CERN Document Server

    Bastian, Nate

    2015-01-01

    A recent surprise in stellar cluster research, made possible through the precision of Hubble Space Telescope photometry, was that some intermediate age (1-2 Gyr) clusters in the Large and Small Magellanic Clouds have main sequence turn-off (MSTO) widths that are significantly broader than would be expected for a simple stellar population (SSP). One interpretation of these extended MSTOs (eMSTOs) is that age spreads of the order of ~500 Myr exist within the clusters, radically redefining our view of stellar clusters, which are traditionally thought of as single age, single metallicity stellar populations. Here we test this interpretation by studying other regions of the CMD that should also be affected by such large age spreads, namely the width of the sub-giant branch (SGB) and the red clump (RC). We study two massive clusters in the LMC that display the eMSTO phenomenon (NGC 1806 & NGC 1846) and show that both have SGB and RC morphologies that are in conflict with expectations if large age spreads exist ...

  2. Comparison between Numerical and Simulation Methods for Age-dependent Branching Models with Immigration

    OpenAIRE

    Martinez, R.; Slavtchova-Bojkova, M.

    2005-01-01

    2000 Mathematics Subject Classification: primary: 60J80, 60J85, secondary: 62M09, 92D40 This work aims to provide and to compare numerical computation and simulation method to estimate the distribution of some relevant variables related to an age-dependent model allowing immigration at state zero. Specifically, we analyze the behaviour of the following variables: the extinction time and the waiting time for the beginning of the survival of population forever. They are strongly related to t...

  3. On the Interpretation of Sub-Giant Branch Morphologies of Intermediate-Age Star Clusters with Extended Main Sequence Turnoffs

    CERN Document Server

    Goudfrooij, Paul; Rosenfield, Philip; Bressan, Alessandro; Marigo, Paola; Correnti, Matteo; Puzia, Thomas H

    2015-01-01

    Recent high-quality photometry of many star clusters in the Magellanic Clouds with ages of 1$\\,-\\,$2 Gyr revealed main sequence turnoffs (MSTOs) that are significantly wider than can be accounted for by a simple stellar population (SSP). Such extended MSTOs (eMSTOs) are often interpreted in terms of an age spread of several $10^8$ yr, challenging the traditional view of star clusters as being formed in a single star formation episode. Li et al. and Bastian & Niederhofer recently investigated the sub-giant branches (SGBs) of NGC 1651, NGC 1806, and NGC 1846, three star clusters in the Large Magellanic Cloud (LMC) that exhibit an eMSTO. They argued that the SGB of these star clusters can be explained only by a SSP. We study these and two other similar star clusters in the LMC, using extensive simulations of SSPs including unresolved binaries. We find that the shapes of the cross-SGB profiles of all star clusters in our sample are in fact consistent with their cross-MSTO profiles when the latter are interpre...

  4. TOWARD THE GENERAL RED GIANT BRANCH SLOPE-METALLICITY-AGE CALIBRATION. I. METALLICITIES, AGES, AND KINEMATICS FOR EIGHT LARGE MAGELLANIC CLOUD CLUSTERS

    International Nuclear Information System (INIS)

    In this paper, we discuss the properties of color-magnitude diagrams, age, metallicity, and radial velocities of eight massive Large Magellanic Cloud (LMC) clusters using data taken from the FORS2 multiobject spectrograph at the 8.2 m Very Large Telescope/Unit Telescope 1. The strong near-infrared Ca II triplet lines of red giant branch stars obtained from the high signal-to-noise ratio spectra are used to determine the metallicity and radial velocity of cluster members. We report for the first time spectroscopically determined metallicity values for four clusters based on the mean [Fe/H] value of ∼10 cluster members each. We found two concentrations in the distribution of ages of the target clusters. Six have ages between 0.8 Gyr and 2.2 Gyr and the other two, NGC 1754 and NGC 1786, are very old. The metallicity of the six intermediate-age clusters, with a mean age of 1.5 Gyr, is -0.49 with a scatter of only 0.04. This tight distribution suggests that a close encounter between the LMC and Small Magellanic Cloud may have caused not only the restart of cluster formation in the LMC but also the generation of the central bar. The metallicity for the two old clusters is similar to that of the other old, metal-poor LMC clusters. We find that the LMC cluster system exhibits disk-like rotation with no clusters appearing to have halo kinematics and there is no evidence of a metallicity gradient in the LMC, in contrast with the stellar population of the Milky Way and M33, where the metallicity decreases as galactocentric distance increases. The LMC's stellar bar may be the factor responsible for the dilution of any kind of gradient in the LMC.

  5. K-Ar age determinations from the northern Damara branch and their implications for the structural and metamorphic evolution of the Damara Orogen, South West Africa/Namibia

    International Nuclear Information System (INIS)

    K-Ar age determination on the fine mineral fractions (< 2 μm) of phyllites and schists were carried out on samples from two separate areas of the north-south-trending coastal branch of the Damara Orogen and additionally from the Tsumeb region. From the northern Damara branch (Sesfontein area), two groups of ages were obtained. One group, around 490 m.y., is interpreted as the cooling age of a regional metamorphism having its peak in this region around 530 m.y. The second, younger group of ages around 460 m.y. seems to be influenced by the mineral composition of the samples taken for determination and as yet is not interpreted in the sence of a second regional metamorphic event. In the southern part of the northern branch (Brandberg West area), the main regional metamorphic event appears to have occurred around 490 m.y. Younger ages in this region may also have been influenced by the mineral composition of the samples or may have been rejuvenated by the intrusion of late to post-tectonic granites. The K-Ar age determinations on the rocks of the Tsumeb area can be related to a main regional metamorphic event dated at about 460 m.y. in this region

  6. Effects of mother tree ages, different rooting mediums, light conditions and auxin treatments on rooting behaviour of Dalbergia sissoo branch cuttings

    Institute of Scientific and Technical Information of China (English)

    Bhupendra Singh; Rajendra Yadav; B.P.Bhatt

    2011-01-01

    Dalbergia sissoo Roxb. is one of the promising multipurpose tree species of South Asia. Most of the plantations of D. sissoo from seeds are facing severe threats due to the die-back disease, which ultimately causes death of this potential tree-species within a few months.Vegetative propagation could avoid the die-back disease. Thirty mother trees of different age-groups of D. sissoo were selected for evaluating the rooting behaviour of branch cuttings from D. sissoo as influenced by auxins (1AA or IBA at 100, 200, 500 mg.L-1), ages of mother trees (10, 4 and 2 years old) and different environment conditions, i.e., different mediums (soil and sand) or light conditions (in shade and open condition). The results show that application of IAA and IBA induced more numbers of cuttings (collected from 10-year-old mother trees) to root compared to control. Branch cuttings of D. sissoo collected from 10-year-old mother trees and planted in soil bed in open conditions had 100.0% of cuttings to root in IAA (100 mg.L-1) and IBA (200 mg.L-1) treatments. Both rooting medium (Soil and sand) influenced significantly (p<0.05) on rooting response of branch cuttings. Soil medium was found to achieve maximum no. of branch cuttings to root, compared to sand medium.

  7. 苏里格气田首口分支水平井钻完井技术%Drilling & completion technology for the first branch horizontal well in Sulige Gas Field

    Institute of Scientific and Technical Information of China (English)

    程元林; 韦海防; 吴学升; 杜松涛; 谢新刚

    2013-01-01

    Sulige gas field is a typical low permeability, low production & low pressure gas field, with relatively poor formation property, and low efficiency of exploration & development for conventional horizontal wells, and low-to-moderate production wells take absolutely majority proportion. Considering the formation characteristics of developed multi pay zone, the drilling&completion technology researches over branch horizontal wells and filed applications are conducted, to further promote the individual production, to increase exploration efficiency, and to reduce integrative exploration cost. In the paper, from the viewpoint of operation difficulties, wellbore structure, sidetracking skills, completion method, etc., some key drilling&completion technologies and applications are in-troduced on Well T7-14-18H, which is the first double-branch horizontal well in Sulige Gas Field. It is achieved that completion with openhole horizontal section+sectional fracturing stimulation techniques successfully. A set of branch horizontal drilling&completion technology is preliminarily formed to fulfill the exploration requirement of Sulige Gas Field, which provide a new technology direction and measure to explore and develop low permeability oil & gas fields.%  苏里格气田属典型低压、低渗、低产的“三低”气田,总体上看储层物性较差,常规水平井开发效率较低,中低产井占绝大多数。为了提高苏里格气田水平井单井产量,提高开发效率,降低综合开发成本,针对苏里格气田多套气藏发育的地质特点,开展了分支水平井钻完井技术研究及现场试验。从施工难点、井身结构、侧钻技术、完井方式等方面介绍

  8. Colour-colour diagrams and extragalactic globular cluster ages. Systematic uncertainties using the (V-K)-(V-I) diagram

    OpenAIRE

    Salaris, Maurizio; Cassisi, Santi

    2006-01-01

    (abridged) We investigate biases in cluster ages and [Fe/H] estimated from the (V-K)-(V-I) diagram, arising from inconsistent Horizontal Branch morphology, metal mixture, treatment of core convection between observed clusters and the theoretical colour grid employed for age and metallicity determinations. We also study the role played by statistical fluctuations of the observed colours, caused by the low total mass of typical globulars. Horizontal Branch morphology is potentially the largest ...

  9. Insulin-like growth factor-I gene therapy increases hippocampal neurogenesis, astrocyte branching and improves spatial memory in female aging rats.

    Science.gov (United States)

    Pardo, Joaquín; Uriarte, Maia; Cónsole, Gloria M; Reggiani, Paula C; Outeiro, Tiago F; Morel, Gustavo R; Goya, Rodolfo G

    2016-08-01

    In rats, learning and memory performance decline during aging, which makes this rodent species a suitable model to evaluate therapeutic strategies of potential value for correcting age-related cognitive deficits. Some of these strategies involve neurotrophic factors like insulin-like growth factor-I (IGF-I), a powerful neuroprotective molecule in the brain. Here, we implemented 18-day long intracerebroventricular (ICV) IGF-I gene therapy in 28 months old Sprague-Dawley female rats, and assessed spatial memory performance in the Barnes maze. We also studied hippocampal morphology using an unbiased stereological approach. Adenovectors expressing the gene for rat IGF-I or the reporter DsRed were used. Cerebrospinal fluid (CSF) samples were taken and IGF-I levels determined by radioimmunoassay. At the end of the study, IGF-I levels in the CSF were significantly higher in the experimental group than in the DsRed controls. After treatment, the IGF-I group showed a significant improvement in spatial memory accuracy as compared with DsRed counterparts. In the dentate gyrus (DG) of the hippocampus, the IGF-I group showed a higher number of immature neurons than the DsRed controls. The treatment increased hippocampal astrocyte branching and reduced their number in the hippocampal stratum radiatum. We conclude that the ependymal route is an effective approach to increase CSF levels of IGF-I and that this strategy improves the accuracy of spatial memory in aging rats. The favorable effect of the treatment on DG neurogenesis and astrocyte branching in the stratum radiatum may contribute to improving memory performance in aging rats. PMID:27188415

  10. Right bundle branch block

    DEFF Research Database (Denmark)

    Bussink, Barbara E; Holst, Anders Gaarsdal; Jespersen, Lasse;

    2013-01-01

    AimsTo determine the prevalence, predictors of newly acquired, and the prognostic value of right bundle branch block (RBBB) and incomplete RBBB (IRBBB) on a resting 12-lead electrocardiogram in men and women from the general population.Methods and resultsWe followed 18 441 participants included in...... men vs. 0.5%/2.3% in women, P <0.001). Significant predictors of newly acquired RBBB were male gender, increasing age, high systolic blood pressure, and presence of IRBBB, whereas predictors of newly acquired IRBBB were male gender, increasing age, and low BMI. Right bundle branch block was associated...... with significantly increased all-cause and cardiovascular mortality in both genders with age-adjusted hazard ratios (HR) of 1.31 [95% confidence interval (CI), 1.11-1.54] and 1.87 (95% CI, 1.48-2.36) in the gender pooled analysis with little attenuation after multiple adjustment. Right bundle branch...

  11. Evolution of long-lived globular cluster stars. II. Sodium abundance variations on the asymptotic giant branch as a function of globular cluster age and metallicity

    Science.gov (United States)

    Charbonnel, Corinne; Chantereau, William

    2016-02-01

    Context. Long-lived stars in globular clusters exhibit chemical peculiarities with respect to their halo counterparts. In particular, sodium-enriched stars are identified as belonging to a second stellar population born from cluster material contaminated by the hydrogen-burning ashes of a first stellar population. Their presence and numbers in different locations of the colour-magnitude diagram provide important constraints on the self-enrichment scenarios. In particular, the ratio of Na-poor to Na-rich stars on the asymptotic giant branch (AGB) has recently been found to vary strongly from cluster to cluster (NGC 6752, 47 Tuc, and NGC 2808), while it is relatively constant on the red giant branch (RGB). Aims: We investigate the impact of both age and metallicity on the theoretical sodium spread along the AGB within the framework of the fast rotating massive star (FRMS) scenario for globular cluster self-enrichment. Methods: We computed evolution models of low-mass stars for four different metallicities ([Fe/H] = -2.2, -1.75, -1.15, -0.5) assuming the initial helium-sodium abundance correlation for second population stars derived from the FRMS models and using mass loss prescriptions on the RGB with two realistic values of the free parameter in the Reimers formula. Results: Based on this grid of models we derive the theoretical critical initial mass for a star born with a given helium, sodium, and metal content that determines whether that star will climb or not the AGB. This allows us to predict the maximum sodium content expected on the AGB for globular clusters as a function of both their metallicity and age. We find that (1) at a given metallicity, younger clusters are expected to host AGB stars exhibiting a larger sodium spread than older clusters and (2) at a given age, higher sodium dispersion along the AGB is predicted in the most metal-poor globular clusters than in the metal-rich ones. We also confirm the strong impact of the mass loss rate in the earlier

  12. The Carina project. VII. Toward the breaking of the age-metallicity degeneracy of red giant branch stars using the C {sub U,} {sub B,} {sub I} index

    Energy Technology Data Exchange (ETDEWEB)

    Monelli, M.; Milone, A. P.; Gallart, C.; Aparicio, A. [Instituto de Astrofísica de Canarias, Calle Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Fabrizio, M.; Cassisi, S.; Buonanno, R. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico Collurania, Via M. Maggini, I-64100 Teramo (Italy); Bono, G. [Dipartimento di Fisica, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Rome (Italy); Stetson, P. B. [Dominion Astrophysical Observatory, NRC-Herzberg, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Walker, A. R. [Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile); Nonino, M. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-40131 Trieste (Italy); Dall' Ora, M. [INAF—Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Ferraro, I.; Iannicola, G.; Pulone, L. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Roma, Via Frascati 33, Monte Porzio Catone, I-00044 Rome (Italy); Thévenin, F., E-mail: monelli@iac.es [Université de Nice Sophia-antipolis, CNRS, Observatoire de la Côte d' Azur, Laboratoire Lagrange, BP 4229, F-06304 Nice (France)

    2014-12-01

    We present an analysis of photometric and spectroscopic data of the Carina dSph galaxy, testing a new approach similar to that used to disentangle multiple populations in Galactic globular clusters (GCs). We show that a proper color combination is able to separate a significant fraction of the red giant branch (RGB) of the two main Carina populations (the old one, ∼12 Gyr, and the intermediate-age one, 4-8 Gyr). In particular, the c {sub U,} {sub B,} {sub I} = (U – B) – (B – I) pseudo-color allows us to follow the RGB of both populations along a relevant portion of the RGB. We find that the oldest stars have a more negative c {sub U,} {sub B,} {sub I} pseudo-color than intermediate-age ones. We correlate the pseudo-color of RGB stars with their chemical properties, finding a significant trend between the iron content and the c {sub U,} {sub B,} {sub I}. Stars belonging to the old population are systematically more metal-poor ([Fe/H] =–2.32 ± 0.08 dex) than the intermediate-age ones ([Fe/H] =–1.82 ± 0.03 dex). This gives solid evidence of the chemical evolution history of this galaxy, and we have a new diagnostic that can allow us to break the age-metallicity degeneracy of H-burning advanced evolutionary phases. We compared the distribution of stars in the c {sub U,} {sub B,} {sub I} plane with theoretical isochrones, finding that no satisfactory agreement can be reached with models developed in a theoretical framework based on standard heavy element distributions. Finally, we discuss possible systematic differences when compared with multiple populations in GCs.

  13. The Carina project. VII. Toward the breaking of the age-metallicity degeneracy of red giant branch stars using the C U, B, I index

    International Nuclear Information System (INIS)

    We present an analysis of photometric and spectroscopic data of the Carina dSph galaxy, testing a new approach similar to that used to disentangle multiple populations in Galactic globular clusters (GCs). We show that a proper color combination is able to separate a significant fraction of the red giant branch (RGB) of the two main Carina populations (the old one, ∼12 Gyr, and the intermediate-age one, 4-8 Gyr). In particular, the c U, B, I = (U – B) – (B – I) pseudo-color allows us to follow the RGB of both populations along a relevant portion of the RGB. We find that the oldest stars have a more negative c U, B, I pseudo-color than intermediate-age ones. We correlate the pseudo-color of RGB stars with their chemical properties, finding a significant trend between the iron content and the c U, B, I. Stars belonging to the old population are systematically more metal-poor ([Fe/H] =–2.32 ± 0.08 dex) than the intermediate-age ones ([Fe/H] =–1.82 ± 0.03 dex). This gives solid evidence of the chemical evolution history of this galaxy, and we have a new diagnostic that can allow us to break the age-metallicity degeneracy of H-burning advanced evolutionary phases. We compared the distribution of stars in the c U, B, I plane with theoretical isochrones, finding that no satisfactory agreement can be reached with models developed in a theoretical framework based on standard heavy element distributions. Finally, we discuss possible systematic differences when compared with multiple populations in GCs.

  14. Branching out

    CERN Document Server

    Biggins, J D

    2010-01-01

    Results on the behaviour of the rightmost particle in the $n$th generation in the branching random walk are reviewed and the phenomenon of anomalous spreading speeds, noticed recently in related deterministic models, is considered. The relationship between such results and certain coupled reaction-diffusion equations is indicated.

  15. Age and petrogenesis of Na-rich felsic rocks in western Iran: Evidence for closure of the southern branch of the Neo-Tethys in the Late Cretaceous

    Science.gov (United States)

    Nouri, Fatemeh; Azizi, Hossein; Golonka, Jan; Asahara, Yoshihiro; Orihashi, Yuji; Yamamoto, Koshi; Tsuboi, Motohiro; Anma, Ryo

    2016-03-01

    Intermediate to felsic volcanic and granitic rocks with high Na2O concentrations (5.2-9.1 wt.%) are widely distributed in the Harsin area along the Zagros thrust zone in western Iran. Most of these rocks are classified as low-potassium tholeiite, display affinity with oceanic plagiogranite and contain somewhat high Na content and low concentrations of K2O, Al2O3, Rb, Sr and Ca. Thus, we prefer to apply the term Na-rich felsic rocks to this complex. U-Pb dating yielded ages of 94.6 ± 2.7 Ma (2σ) from baddeleyite and 95.0 ± 2.4 Ma (2σ) from zircon grains, indicating that the complex crystallized in the Late Cretaceous. Based on the mineral compositions, the crystallization occurred at low pressures (mostly < 2 kbar) and low temperatures (< 750 °C). High initial ratios of 143Nd/144Nd (0.51288-0.51304) and positive values of ɛNd(t) (+ 7.0 to + 11.5) are consistent with those of mid-oceanic ridge basalt (MORB). During collision of the Arabian plate and Biston-Avoraman block in the Late Cretaceous, an increasing geothermal gradient was responsible for partial melting of altered mafic rocks and for producing the Na-rich felsic rocks in the Harsin area. The presence of these types of rocks along the main Zagros fault indicates local collisions. These collisions were caused by southwestward subduction under the Arabian plate in the southern branch of the Neo-Tethys. This event was the first stage of the Zagros collision, which was followed by collision of the Arabian and Iranian plates during the Eocene through Neogene.

  16. Parametric study for horizontal steam generator modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ovtcharova, I. [Energoproekt, Sofia (Bulgaria)

    1995-12-31

    In the presentation some of the calculated results of horizontal steam generator PGV - 440 modelling with RELAP5/Mod3 are described. Two nodalization schemes have been used with different components in the steam dome. A study of parameters variation on the steam generator work and calculated results is made in cases with separator and branch.

  17. Factors of poor prognosis of visceral leishmaniasis among children under 12 years of age. A retrospective monocentric study in Belo Horizonte, State of Minas Gerais, Brazil, 2001-2005

    Directory of Open Access Journals (Sweden)

    Alexandre Sérgio da Costa Braga

    2013-01-01

    Full Text Available INTRODUTION: A major concern with the visceral leishmaniasis (VL is its high lethality rate, even with proper treatment. Low age, prior malnutrition, disease duration prior to diagnosis, severe anemia, fever for more than 60 days, diarrhea and jaundice are known poor prognostic factors. The goals of this study are to describe the clinical and laboratory characteristics of VL among children under 12 years of age and to identify the factors associated with VL poor outcome. METHODS: Two hundred and fifty children under 12 years of age with confirmed VL admitted to Hospital João Paulo II (FHEMIG, Belo Horizonte, Brazil, between January 2001 and December 2005 were evaluated retrospectively. The primary outcome was the poor clinical evolution: sepsis, and/or pneumonia, and/or urinary tract infection, and/or of bleeding (expect epistaxis, and/or severe neutropenia (neutrophil < 500 cells/mm3. Odds ratio (crude and adjusted and its 95% confidence interval for each variable were calculated. Values less than 0.05 were considered significant. RESULTS: Average age was 3.3 years (3.6 months-11.6 years, 71.2% were younger than 5 years and 47.2% lived in Metropolitan Area of Belo Horizonte. The mean fatality rate was 3.6%. Sixty-six (26.4% patients presented poor evolution. After a multivariate analysis, age <18 months, abnormal respiratory physical examination on hospital admission, and platelets <85,000/mm3 remained associated with increased chance of poor evolution. CONCLUSIONS: The results suggest that patients aged between 12 and 18 months, with platelet counts bellow 85,000/mm3, and respiratory abnormalities at admission should be considered potentially severe.

  18. Colour-colour diagrams and extragalactic globular cluster ages. Systematic uncertainties using the (V-K)-(V-I) diagram

    CERN Document Server

    Salaris, M; Salaris, Maurizio; Cassisi, Santi

    2006-01-01

    (abridged) We investigate biases in cluster ages and [Fe/H] estimated from the (V-K)-(V-I) diagram, arising from inconsistent Horizontal Branch morphology, metal mixture, treatment of core convection between observed clusters and the theoretical colour grid employed for age and metallicity determinations. We also study the role played by statistical fluctuations of the observed colours, caused by the low total mass of typical globulars. Horizontal Branch morphology is potentially the largest source of uncertainty. A single-age system harbouring a large fraction of clusters with an HB morphology systematically bluer than the one accounted for in the theoretical colour grid, can simulate a bimodal population with an age difference as large as 8 Gyr. When only the redder clusters are considered, this uncertainty is almost negligible, unless there is an extreme mass loss along the Red Giant Branch phase. The metal mixture affects mainly the redder clusters; the effect of colour fluctuations becomes negligible for...

  19. Horizontal Equity, Once More

    OpenAIRE

    Richard A. Musgrave

    1990-01-01

    Reconsiders the proposition that vertical equity is the primary norm for tax design, with horizontal equity a mere derivative therefrom. In the case of limited policy options, vertical and horizontal equity goals may conflict so that a trade-off will be needed. Independent values must then be assigned to each, confirming the standing of a horizontal as well as vertical equity as a primary norm.

  20. New Potassium-Argon Ages for Georgiaites and the Upper Eocene Dry Branch Formation (Twiggs Clay Member): Inferences About Tektite Stratigraphic Occurrence

    Science.gov (United States)

    Albin, E. F.; Wampler, J. M.

    1996-03-01

    The tektites of east-central Georgia, called "georgiaites," are a subset of the larger North American tektite strewn field. Previous studies have reported the potassium-argon age of Georgia tektites at 32.0 Ma, 33.7 Ma, and 34.0 Ma, respectively. Glass et al., using the 40Ar-39Ar method, obtained a 34.5 Ma age for a single Muong Nong type georgiaite. Corrected fission track ages given by Storzer et al. have a range between 1.0 and 35.8 Ma with the lower dates accounted for by post-depositional thermal alteration. However, isotopic dating of North American microtektites from Barbados suggests that the strewn field was produced at 35.4 (+/- 0.6) Ma. In addition to the lack of consistently reliable age data for Georgia tektites, their stratigraphic occurrence has yet to be satisfactorily resolved. Although the North American strewn field was deposited in the late Eocene, georgiaites have been found only on formations ranging in age from Oligocene to Pleistocene so are thought to have been transported from their original site of deposition. In this investigation we present new potassium-argon ages for the Georgia tektites and an upper Eocene formation in an effort to resolve tektite stratigraphic location in coastal main deposits of east-central Georgia.

  1. Branched polynomial covering maps

    DEFF Research Database (Denmark)

    Hansen, Vagn Lundsgaard

    1999-01-01

    A Weierstrass polynomial with multiple roots in certain points leads to a branched covering map. With this as the guiding example, we formally define and study the notion of a branched polynomial covering map. We shall prove that many finite covering maps are polynomial outside a discrete branch...... set. Particular studies are made of branched polynomial covering maps arising from Riemann surfaces and from knots in the 3-sphere....

  2. Branched polynomial covering maps

    DEFF Research Database (Denmark)

    Hansen, Vagn Lundsgaard

    2002-01-01

    A Weierstrass polynomial with multiple roots in certain points leads to a branched covering map. With this as the guiding example, we formally define and study the notion of a branched polynomial covering map. We shall prove that many finite covering maps are polynomial outside a discrete branch...... set. Particular studies are made of branched polynomial covering maps arising from Riemann surfaces and from knots in the 3-sphere. (C) 2001 Elsevier Science B.V. All rights reserved....

  3. A Study on Numerical Simulation of CBM Pinnate Horizontal Well for Near-Wellbore Seepage

    Directory of Open Access Journals (Sweden)

    Tingting Jiang

    2012-11-01

    Full Text Available The motive of the study is to establish a near-wellbore seepage model of Coalbed Methane (CBM pinnate horizontal well according to the potential superposition principle and the equivalent well diameter model. The corresponding calculation program has been achieved based on C++ computer language to analyze the effects of branch distribution, branch position and length on isobar distribution of CBM pinnate horizontal well. The results show that the isobar distribution of CBM pinnate horizontal well is closely related to its own wellbore configuration. When the two branches are at the same side, the isobars incline to the branch side. When the branch position moves from the heel end to the toe end along the main borehole, the morphology of isobars transforms from oval to slant triangle. With the increase of branch length, the influence on the morphology of isobars increases gradually.

  4. Ages of globular clusters a new approach

    CERN Document Server

    Jiménez, R; Jørgensen, U G; MacDonald, J; Pagel, B

    1996-01-01

    We have applied a new method to analyze the horizontal branch (HB) morphology in relation to the distribution of stars near the red giant branch (RGB) tip for the globular clusters M22, M5, M68, M107, M72, M92, M3 and 47 Tuc. This new method permits determination of the cluster ages to greater accuracy than conventional isochrone fitting. Using the method in conjunction with our new high-quality photometric data for RGB and HB stars in the first five of these clusters, we discuss the origins of the spread in color on the HB and its relation to the `second parameter' problem. The oldest clusters in our sample are found to have relatively low ages, 13.5 Gyr. A 1 sigma uncertainty in each of the parameters of mass and helium content combined with the effects of helium diffusion gives a lower limit for the age of the oldest clusters of 9.7 Gyr.

  5. Numerical Simulation of Coalbed Methane Seepage in Pinnate Horizontal Well Based on Multi-Flow Coupling Model

    Directory of Open Access Journals (Sweden)

    Tingting Jiang

    2012-08-01

    Full Text Available The motive of the study is to establish a seepage flow model of pinnate horizontal well in infinite reservoir according to the characteristics of 3D distribution of CBM pinnate horizontal well. Taking flow pressure drop along the main and branch boreholes into consideration, the fluid flow formulas of CBM pinnate horizontal well are proposed. The corresponding calculation program has been achieved based on C++ computer language to analyze the effects of branch symmetry, angle between main and branch boreholes, branch number on isobar distribution, inflow profiles of branch and main boreholes of CBM pinnate horizontal well. The results show that: the isobars present symmetry property by the main borehole when branches are symmetrical. At the same time, production per unit length of main borehole at branch node declines rapidly while the radial inflow curves of branch boreholes are almost the same. With the increasing of angle between branch and main boreholes, isobars transfer into trapezoid from slantwise triangle, meanwhile, the inflow rate of branch borehole increases gradually. Isobars transfer into irregular polygon with the increase of branch number. Moreover, the inflow rate of main and branch boreholes all decreases with the increasing of branch number.

  6. Estudio del horizonte local

    OpenAIRE

    Ros Ferré, Rosa Maria

    2009-01-01

    El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical).

  7. Horizontal Integration of Knowledge

    Czech Academy of Sciences Publication Activity Database

    Klimešová, Dana; Vostrovský, V.

    Palma de Mallorca: IASTED, 2008, s. 191-196. ISBN 978-0-88986-755-0. [ Artificial Intelligence and Soft Computing (ASC 2008). Palma de Mallorca (ES), 01.09.2008-03.09.2008] Institutional research plan: CEZ:AV0Z10750506 Keywords : Intelligent systems * horizontal knowledge integration * multi-criteria evaluation * decision support Subject RIV: IN - Informatics, Computer Science http://library.utia.cas.cz/separaty/2008/ZOI/klimesova-horizontal integration of knowledge.pdf

  8. Galactic Globular Cluster Relative Ages. II

    CERN Document Server

    De Angeli, F; Cassisi, S; Busso, G; Recio-Blanco, A; Salaris, M; Aparicio, A; Rosenberg, A L

    2005-01-01

    We present accurate relative ages for a sample of 55 Galactic globular clusters. The ages have been obtained by measuring the difference between the horizontal branch and the turnoff in two, internally photometrically homogeneous databases. The mutual consistency of the two data sets has been assessed by comparing the ages of 16 globular clusters in common between the two databases. We have also investigated the consistency of our relative age determination within the recent stellar model framework. All clusters with [Fe/H]-0.8 are ~1 Gyr younger than the most metal poor ones, with a relatively small age dispersion, though the metal rich sample is still too small to allow firmer conclusions. There is no correlation of the cluster age with the Galactocentric distance. We briefly discuss the implication of these observational results for the formation history of the Galaxy.

  9. Bank branches in supermarkets

    OpenAIRE

    Lawrence J. Radecki; John Wenninger; Daniel Orlow

    1996-01-01

    The largest U.S. commercial banks are restructuring their retail operations to reduce the cost disadvantage resulting from a stagnant deposit base and stiffer competition. As part of this effort, some banks are opening "supermarket," or "in-store," branches: a new type of banking office within a large retail outlet. An alternative to the traditional bank office, the supermarket branch enables banks to improve the efficiency of the branch network and offer greater convenience to customers.

  10. Evolution of long-lived globular cluster stars. II. Sodium abundance variations on the asymptotic giant branch as a function of globular cluster age and metallicity

    CERN Document Server

    Charbonnel, C

    2016-01-01

    Long-lived stars in GCs exhibit chemical peculiarities with respect to their halo counterparts. In particular, Na-enriched stars are identified as belonging to a 2d stellar population born from cluster material contaminated by the H-burning ashes of a 1st stellar population. Their presence and numbers in different locations of the CMDs provide important constraints on the self-enrichment scenarios. In particular, the ratio of Na-poor to Na-rich stars on the AGB has recently been found to vary strongly from cluster to cluster, while it is relatively constant on the RGB. We investigate the impact of both age and metallicity on the theoretical Na spread along the AGB within the framework of the fast rotating massive stars scenario for GC self-enrichment. (tb continued)

  11. Aging.

    Science.gov (United States)

    Park, Dong Choon; Yeo, Seung Geun

    2013-09-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  12. Horizontal carbon nanotube alignment.

    Science.gov (United States)

    Cole, Matthew T; Cientanni, Vito; Milne, William I

    2016-09-21

    The production of horizontally aligned carbon nanotubes offers a rapid means of realizing a myriad of self-assembled near-atom-scale technologies - from novel photonic crystals to nanoscale transistors. The ability to reproducibly align anisotropic nanostructures has huge technological value. Here we review the present state-of-the-art in horizontal carbon nanotube alignment. For both in and ex situ approaches, we quantitatively assess the reported linear packing densities alongside the degree of alignment possible for each of these core methodologies. PMID:27546174

  13. Materials Test Branch

    Science.gov (United States)

    Gordon, Gail

    2012-01-01

    The Materials Test Branch resides at Marshall Space Flight Center's Materials and Processing laboratory and has a long history of supporting NASA programs from Mercury to the recently retired Space Shuttle. The Materials Test Branch supports its customers by supplying materials testing expertise in a wide range of applications. The Materials Test Branch is divided into three Teams, The Chemistry Team, The Tribology Team and the Mechanical Test Team. Our mission and goal is to provide world-class engineering excellence in materials testing with a special emphasis on customer service.

  14. Branching processes in biology

    CERN Document Server

    Kimmel, Marek

    2015-01-01

    This book provides a theoretical background of branching processes and discusses their biological applications. Branching processes are a well-developed and powerful set of tools in the field of applied probability. The range of applications considered includes molecular biology, cellular biology, human evolution and medicine. The branching processes discussed include Galton-Watson, Markov, Bellman-Harris, Multitype, and General Processes. As an aid to understanding specific examples, two introductory chapters, and two glossaries are included that provide background material in mathematics and in biology. The book will be of interest to scientists who work in quantitative modeling of biological systems, particularly probabilists, mathematical biologists, biostatisticians, cell biologists, molecular biologists, and bioinformaticians. The authors are a mathematician and cell biologist who have collaborated for more than a decade in the field of branching processes in biology for this new edition. This second ex...

  15. The Olive Branch Awards.

    Science.gov (United States)

    Harnack, William

    1984-01-01

    The first annual Olive Branch Awards, sponsored by the Writers' and Publishers Alliance and the Editors' Organizing Committee, were given to ten magazines, out of 60 that submitted entries. Winning entries are described briefly. (IM)

  16. FUNDAMENTAL PARAMETERS, INTEGRATED RED GIANT BRANCH MASS LOSS, AND DUST PRODUCTION IN THE GALACTIC GLOBULAR CLUSTER 47 TUCANAE

    International Nuclear Information System (INIS)

    Fundamental parameters and time evolution of mass loss are investigated for post-main-sequence stars in the Galactic globular cluster 47 Tucanae (NGC 104). This is accomplished by fitting spectral energy distributions (SEDs) to existing optical and infrared photometry and spectroscopy, to produce a true Hertzsprung-Russell diagram. We confirm the cluster's distance as d = 4611+213-200 pc and age as 12 ± 1 Gyr. Horizontal branch models appear to confirm that no more red giant branch mass loss occurs in 47 Tuc than in the more metal-poor ω Centauri, though difficulties arise due to inconsistencies between the models. Using our SEDs, we identify those stars that exhibit infrared excess, finding excess only among the brightest giants: dusty mass loss begins at a luminosity of ∼1000 Lsun, becoming ubiquitous above L = 2000 Lsun. Recent claims of dust production around lower-luminosity giants cannot be reproduced, despite using the same archival Spitzer imagery.

  17. Koenigs function and branching processes

    OpenAIRE

    Tchikilev, O. G.

    2001-01-01

    An explicit solution of time-homogeneous pure birth branching processes is described. It gives alternative extensions for the negative binomial distribution (branching processes with immigration) and for the Furry-Yule distribution (branching processes without immigration).

  18. Conceptualising horizontal politics

    OpenAIRE

    Harding, Eloise Mary

    2012-01-01

    This project investigates the likelihood of a distinctive ideology emerging from what are known as ‘horizontal’ political movements – those which, in brief, aim to operate non-hierarchically guided by principles such as affinity – and furthermore to identify the potential components of such an ideology. The methodology is broadly based on that developed by Freeden, namely an analysis of the conceptual morphology of the ideas put out by horizontal movements. The sources used derive largely fro...

  19. Synthesis of branched polysaccharides with tunable degree of branching

    NARCIS (Netherlands)

    Ciric, Jelena; Loos, Katja

    2013-01-01

    An in vitro enzyme-catalyzed tandem reaction using the enzymes phosphorylase b from rabbit muscle and Deinococcus geothermalis glycogen branching enzyme (Dg GBE) to obtain branched polyglucans with tunable degree of branching (2% divided by 13%) is presented. The tunable degree of branching is obtai

  20. Clear evidence for the presence of second-generation asymptotic giant branch stars in metal-poor Galactic globular clusters

    CERN Document Server

    Garcia-Hernandez, D A; Monelli, M; Cassisi, S; Stetson, P B; Zamora, O; Shetrone, M; Lucatello, S

    2015-01-01

    Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation with a chemical pattern typical of halo field stars and a second generation (SG) enriched in Na and Al and depleted in O and Mg. Both stellar generations are found at different evolutionary stages (e.g., the main-sequence turnoff, the subgiant branch, and the red giant branch). The non detection of SG asymptotic giant branch (AGB) stars in several metal-poor ([Fe/H] < -1) GCs suggests that not all SG stars ascend the AGB phase, and that failed AGB stars may be very common in metal-poor GCs. This observation represents a serious problem for stellar evolution and GC formation/evolution theories. We report fourteen SG-AGB stars in four metal-poor GCs (M 13, M 5, M 3, and M 2) with different observational properties: horizontal branch (HB) morphology, metallicity, and age. By combining the H-band Al abundances obtained by the APOGEE survey with ground-based optical photometry, we identify SG Al-rich AGB stars in...

  1. Tracheobronchial Branching Anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Min Ji; Kim, Young Tong; Jou, Sung Shick [Soonchunhyang University, Cheonan Hospital, Cheonan (Korea, Republic of); Park, A Young [Soonchunhyang University College of Medicine, Asan (Korea, Republic of)

    2010-04-15

    There are various congenital anomalies with respect to the number, length, diameter, and location of tracheobronchial branching patterns. The tracheobronchial anomalies are classified into two groups. The first one, anomalies of division, includes tracheal bronchus, cardiac bronchus, tracheal diverticulum, pulmonary isomerism, and minor variations. The second one, dysmorphic lung, includes lung agenesis-hypoplasia complex and lobar agenesis-aplasia complex

  2. Biomimetic Branched Hollow Fibers Templated by Self-assembled Fibrous Polyvinylpyrrolidone (PVP) Structures in Aqueous Solution

    OpenAIRE

    Qiu, Penghe; Mao, Chuanbin

    2010-01-01

    Branched hollow fibers are common in nature, but to form artificial fibers with a similar branched hollow structure is still a challenge. We discovered that polyvinylpyrrolidone (PVP) could self-assemble into branched hollow fibers in an aqueous solution after aging the PVP solution for about two weeks. Based on this finding, we demonstrated two approaches by which the self-assembly of PVP into branched hollow fibers could be exploited to template the formation of branched hollow inorganic fi...

  3. Well Spacing for Horizontal Wells

    Directory of Open Access Journals (Sweden)

    C.D.S. Keuengoua

    2011-06-01

    Full Text Available In the developing phase of a hydrocarbon reservoir and planning for drilling the production wells, it is necessary to drill the wells in an appropriate spacing to achieve maximum economic revenues during the reservoir life span. Well spacing which is the real location and interrelationship between producing oil or gas wells in an oil field is an important parameter. It is determined for the maximum ultimate production of a given reservoir and should be taken in consideration during well planning to avoid drilling of unnecessary wells. This study presents the concept of drainage area on horizontal well and horizontal productivity indices with different equations and their applications. A user friendly Excel Spreadsheet program was developed to calculate the productivity values of horizontal wells using three major available productivity equations. Also, the developed spreadsheet program was used to evaluate the effect of well spacing on the productivities of horizontal wells using productivity index approach and drainage area concept. It also helps to review the comparison between vertical and horizontal wells spacing based on drainage area concept. This program was validated, and then was used to study the effect of horizontal well length on the ratio of horizontal well productivity to vertical well productivity. The results show that higher ratio of horizontal well productivity to vertical well productivity values are obtained with increase length of the horizontal well. It is a very useful tool for making decision about the application of well spacing for horizontal wells.

  4. Horizontally shaken impact pendulums

    Science.gov (United States)

    Alexander, T. J.; Xu, Y.; Sidhu, H.

    2016-03-01

    We consider two pendulum masses attached to the same pivot point and which interact with each other through Hertzian impacts. We show that this splitting of the mass leads to an instability in the conservative case, in which initially synchronized large amplitude motion may evolve into out-of-phase (impacting) motion. We then study in detail the response of the impacting masses in the presence of damping and driving through horizontal shaking of the pivot point. We find that synchronized modes are usually accompanied by small amplitude quasi-periodic, or even chaotic, impacts and a number of multi-period solutions may appear in the bifurcation diagram. We reveal the existence and stability of a number of impact modes and scan the frequency response of the system to a series of initial conditions to identify which modes may be more easily generated in experiment.

  5. PRODUCTIVITY OF FRACTURED HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Stjepan Antolović

    2009-12-01

    Full Text Available The interest and performance of horizontal drilling and completions has increased during the last two decades. Horizontal wells are advantageous compared to vertical wells in thin reservoirs, reservoirs with favorable vertical permeability and reservoirs with water and gas coning problems. In many reservoirs, the ratio of horizontal permeability to the vertical permeability is substantially larger than one and often is close to 10. Thus, these reservoirs are very good candidates for hydraulic fracturing. By hydraulic fracturing one or more fractures are created, which can be longitudinal or orthogonal. By that, flow is altered and it mostly conducts horizontally through reservoir toward horizontal wellbore. With this altered flow, fluid is produced faster, with less pressure loss by fluid unit of produced fluid. Some of the existing mathematical models to determine the productivity of multifractured horizontal wells are presented in this work (the paper is published in Croatian.

  6. DRILL BITS FOR HORIZONTAL WELLS

    OpenAIRE

    Paolo Macini

    1996-01-01

    This paper underlines the importance of the correct drill bit application in horizontal wells. Afler the analysis of the peculiarities of horizontal wells and drainholes drilling techniques, advantages and disadvantages of the application of both roller cone and fixed cutters drill bits have been discussed. Also, a review of the potential specific featuries useful for a correct drill bit selection in horizontal small diameter holes has been highlighted. Drill bits for these special applicatio...

  7. PRODUCTIVITY OF FRACTURED HORIZONTAL WELLS

    OpenAIRE

    2009-01-01

    The interest and performance of horizontal drilling and completions has increased during the last two decades. Horizontal wells are advantageous compared to vertical wells in thin reservoirs, reservoirs with favorable vertical permeability and reservoirs with water and gas coning problems. In many reservoirs, the ratio of horizontal permeability to the vertical permeability is substantially larger than one and often is close to 10. Thus, these reservoirs are very good candidates for hydraulic...

  8. Horizontal drilling in shallow reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Murray, W.F. Jr.; Schrider, L.A.; McCallister, J.V.; Mazza, R.L.

    1993-12-31

    Belden & Blake and the US DOE will cofund a horizontal well to be drilled in the Clinton Sandstone as part of the DOE`s multi well program titled ``Horizontal Drilling in Shallow Geologic Complex Reservoirs.`` This well will be located in Mahoning County, Ohio in an area which has demonstrated above average Clinton gas production. To the best of our knowledge, this will be the first horizontal well drilled to the Clinton Sand formation in Ohio. Since many of the remaining Clinton Sand drilling sites are of poorer reservoir quality, they may not be developed unless technology such as horizontal drilling can be successfully demonstrated.

  9. Tau leptonic branching ratios

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Garrido, L; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    A sample of 62249 \\tau-pair events is selected from data taken with the ALEPH detector in 1991, 1992 and 1993. The measurement of the branching fractions for \\tau decays into electrons and muons is presented with emphasis on the study of systematic effects from selection, particle identification and decay classification. Combined with the most recent ALEPH determination of the \\tau lifetime, these results provide a relative measurement of the leptonic couplings in the weak charged current for transverse W bosons.

  10. Holographic Coulomb branch vevs

    CERN Document Server

    Skenderis, K; Skenderis, Kostas; Taylor, Marika

    2006-01-01

    We compute holographically the vevs of all chiral primary operators for supergravity solutions corresponding to the Coulomb branch of N=4 SYM and find exact agreement with the corresponding field theory computation. Using the dictionary between 10d geometries and field theory developed to extract these vevs, we propose a gravity dual of a half supersymmetric deformation of N=4 SYM by certain irrelevant operators.

  11. Modeling branching in cereals

    OpenAIRE

    Jochem B. Evers; Vos, Jan

    2013-01-01

    Cereals and grasses adapt their structural development to environmental conditions and the resources available. The primary adaptive response is a variable degree of branching, called tillering in cereals. Especially for heterogeneous plant configurations the degree of tillering varies per plant. Functional–structural plant modeling (FSPM) is a modeling approach allowing simulation of the architectural development of individual plants, culminating in the emergent behavior at the canopy level....

  12. Critical evaluation of branch polarity and apical dominance as dictators of colony astogeny in a branching coral.

    Directory of Open Access Journals (Sweden)

    Lee Shaish

    Full Text Available The high morphological resemblance between branching corals and trees, can lead to comparative studies on pattern formation traits, best exemplified in plants and in some cnidarians. Here, 81 branches of similar size of the hermatypic coral Stylophora pistillata were lopped of three different genets, their skeletons marked with alizarin red-S, and divided haphazardly into three morphometric treatment groups: (I upright position; (II horizontal position, intact tip; and (III horizontal position, cut tip. After 1 y of in-situ growth, the 45 surviving ramets were brought to the laboratory, their tissues removed and their architectures analyzed by 22 morphological parameters (MPs. We found that within 1 y, isolated branches developed into small coral colonies by growing new branches from all branch termini, in all directions. No architectural dissimilarity was assigned among the three studied genets of treatment I colonies. However, a major architectural disparity between treatment I colonies and colonies of treatments II and III was documented as the development of mirror structures from both sides of treatments II and III settings as compared to tip-borne architectures in treatment I colonies. We did not observe apical dominance since fragments grew equally from all branch sides without documented dominant polarity along branch axis. In treatment II colonies, no MP for new branches originating either from tips or from branch bases differed significantly. In treatment III colonies, growth from the cut tip areas was significantly lower compared to the base, again, suggesting lack of apical dominance in this species. Changes in branch polarity revealed genet associated plasticity, which in one of the studied genets, led to enhanced growth. Different genets exhibited canalization flexibility of growth patterns towards either lateral growth, or branch axis extension (skeletal weight and not porosity was measured. This study revealed that colony

  13. Inferring horizontal gene transfer.

    Directory of Open Access Journals (Sweden)

    Matt Ravenhall

    2015-05-01

    Full Text Available Horizontal or Lateral Gene Transfer (HGT or LGT is the transmission of portions of genomic DNA between organisms through a process decoupled from vertical inheritance. In the presence of HGT events, different fragments of the genome are the result of different evolutionary histories. This can therefore complicate the investigations of evolutionary relatedness of lineages and species. Also, as HGT can bring into genomes radically different genotypes from distant lineages, or even new genes bearing new functions, it is a major source of phenotypic innovation and a mechanism of niche adaptation. For example, of particular relevance to human health is the lateral transfer of antibiotic resistance and pathogenicity determinants, leading to the emergence of pathogenic lineages. Computational identification of HGT events relies upon the investigation of sequence composition or evolutionary history of genes. Sequence composition-based ("parametric" methods search for deviations from the genomic average, whereas evolutionary history-based ("phylogenetic" approaches identify genes whose evolutionary history significantly differs from that of the host species. The evaluation and benchmarking of HGT inference methods typically rely upon simulated genomes, for which the true history is known. On real data, different methods tend to infer different HGT events, and as a result it can be difficult to ascertain all but simple and clear-cut HGT events.

  14. Almost horizontal turbulence

    International Nuclear Information System (INIS)

    The paper is published without modifications. Kolmogorov's manuscript was apparently prepared during his participation in one of expeditions of the ship 'D. Mendeleev' to the Atlantic Ocean (1969) or in a circumnavigation of the world (1971) organized by the Institute for Oceanology led at the time by A.S. Monin. As Kolmogorov himself wrote, the choice of the topic was stimulated by observations concerning '...meanders with horizontal sizes of hundreds of kilometers on a flow involving a layer of hundreds of meters, with subsequent disintegration of these meanders into vortices gradually decreasing in size to several kilometers'. In modern terminology, the paper is devoted to the problem of intensive mixing in pycnoclines, that is, thin layers of stratified fluid, caused by internal waves whose frequencies are less than the Brent-Vaeisaelae frequency. Here I would like to note two circumstances. The first is the scientific insight characteristic for Kolmogorov; this very approach was later reflected in numerous publications (see, for instance, the monograph by V.S. Modevich, V.I. Nikulin, and A.G. Stetsenko 'Dynamics of internal mixing in a stratified medium', Institute for Hydromechanics, Academy of Sciences of Ukraine, Naukova Dumka, Kiev 1988). The second, the more significant in my opinion, is the genuine intellectual curiosity and breadth of thought of this great thinker, who studied not only the most abstract mathematical constructions but also got his head out of the clouds with great interest to solve concrete applied problems

  15. Evolution of the horizontal drilling operations in the Ramos field; Evolucion de la perforacion horizontal en el Yacimiento Ramos

    Energy Technology Data Exchange (ETDEWEB)

    Piasco, Luis E.; Alegria, Antonio; Eguia, Hugo V.; Luna, Juan C. [PLUSPETROL Exploracion y Produccion, Buenos Aires (Argentina); Marcelo, Nguyen [PLUSPETROL Peru Corporation, Lima (Peru)

    1999-07-01

    The purpose of this paper is to show the progress related to the horizontal drilling operations in the Ramos Field in accordance with the technology evolution and the reservoir knowledge. The Ramos field, characterized as a natural fractured reservoir of quartzitic sandstones, has been subject for the application of the horizontal drilling techniques with the objective of maximize the production and to avoid water conning problems in the future. This paper describes chronologically, the experiences and the technology that helped to achieve the different proposed objectives and to reach improvements on the horizontal an Malt drilling operations. On this way, we finish successfully the drilling and completion operations in the Ramos 1010 multilateral well. This well has two cased branches and is the first well in his type in the whole subandean belt. (author)

  16. Thermal Energy Conversion Branch

    Science.gov (United States)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  17. Combustion Branch Website Development

    Science.gov (United States)

    Bishop, Eric

    2004-01-01

    The NASA combustion branch is a leader in developing and applying combustion science to focused aerospace propulsion systems concepts. It is widely recognized for unique facilities, analytical tools, and personnel. In order to better communicate the outstanding research being done in this Branch to the public and other research organization, a more substantial website was desired. The objective of this project was to build an up-to-date site that reflects current research in a usable and attractive manner. In order to accomplish this, information was requested from all researchers in the Combustion branch, on their professional skills and on the current projects. This information was used to fill in the Personnel and Research sections of the website. A digital camera was used to photograph all personnel and these photographs were included in the personnel section as well. The design of the site was implemented using the latest web standards: xhtml and external css stylesheets. This implementation conforms to the guidelines recommended by the w3c. It also helps to ensure that the web site is accessible by disabled users, and complies with Section 508 Federal legislation (which mandates that all Federal websites be accessible). Graphics for the new site were generated using the gimp (www.gimp.org) an open-source graphics program similar to Adobe Photoshop. Also, all graphics on the site were of a reasonable size (less than 20k, most less than 2k) so that the page would load quickly. Technologies such as Macromedia Flash and Javascript were avoided, as these only function on some clients which have the proper software installed or enabled. The website was tested on different platforms with many different browsers to ensure there were no compatibility issues. The website was tested on windows with MS IE 6, MSIE 5 , Netscape 7, Mozilla and Opera. On a Mac, the site was tested with MS IE 5 , Netscape 7 and Safari.

  18. Path-valued branching processes and nonlocal branching superprocesses

    CERN Document Server

    Li, Zenghu

    2012-01-01

    A family of continuous-state branching processes with immigration are constructed as the solution flow of a stochastic equation system driven by time-space noises. The family can be regarded as an inhomogeneous increasing path-valued branching process with immigration. Two nonlocal branching immigration superprocesses can be defined from the flow. We identify explicitly the branching and immigration mechanisms of those processes. The results provide new perspectives into the tree-valued Markov processes of Aldous and Pitman [Ann. Inst. H. Poincare Probab. Statist. 34 (1998), 637--686] and Abraham and Delmas [Ann. Probab. To appear].

  19. Maritime Branch Analysis

    DEFF Research Database (Denmark)

    Mougaard, Krestine; Neugebauer, Line Maria; Garcia i Mateu, Adrià;

    after-sales service and have therefore embarked on business development activities that tightly combine product and service offerings in their portfolios. Closer customer contact, commoditisation of goods, total cost of ownership, and product liability are just some of the reasons for this transition......The vast majority of countries in the developed world are now dependent on their service sectors for between 70-80% of their gross domestic product. Even companies with decades of expertise in producing manufactured products are experiencing an increased need to understand before-, during- and...... and influencing a move towards intensified service integration into business- and product development activities. The workbook has been created by condensing the transcripts and the insights we have gained from a wealth of studies across the maritime branch, and it serves to provide a unique insight...

  20. Quiver Varieties and Branching

    Directory of Open Access Journals (Sweden)

    Hiraku Nakajima

    2009-01-01

    Full Text Available Braverman and Finkelberg recently proposed the geometric Satake correspondence for the affine Kac-Moody group Gaff [Braverman A., Finkelberg M., arXiv:0711.2083]. They conjecture that intersection cohomology sheaves on the Uhlenbeck compactification of the framed moduli space of Gcpt-instantons on $R^4/Z_r$ correspond to weight spaces of representations of the Langlands dual group $G_{aff}^{vee}$ at level $r$. When $G = SL(l$, the Uhlenbeck compactification is the quiver variety of type $sl(r_{aff}$, and their conjecture follows from the author's earlier result and I. Frenkel's level-rank duality. They further introduce a convolution diagram which conjecturally gives the tensor product multiplicity [Braverman A., Finkelberg M., Private communication, 2008]. In this paper, we develop the theory for the branching in quiver varieties and check this conjecture for $G = SL(l$.

  1. Variation in terminology: capoeira in Belo Horizonte

    Directory of Open Access Journals (Sweden)

    César Nardelli Cambraia

    2014-12-01

    Full Text Available In this pilot study we analyzed the variation in the terminology of capoeira in Belo Horizonte. The terms referring to 69 videotaped movements of capoeira were collected from 10 informants (5 men and 5 women, aged between 25 and 32 years, capoeira teachers. As a result we obtained 294 different terms whose patterns of variation are distributed among 15 types. We tested the hypothesis that the figurative terms tend to be replaced by non-figurative ones, and it was confirmed by the collected data. This trend was the result of a search for transparency in terminology, making the terms more descriptive in relation to capoeira’s movements.

  2. Methods and Technologies Branch (MTB)

    Science.gov (United States)

    The Methods and Technologies Branch focuses on methods to address epidemiologic data collection, study design and analysis, and to modify technological approaches to better understand cancer susceptibility.

  3. Can the branching exponent reliably relate the branching indexes?

    Czech Academy of Sciences Publication Activity Database

    Netopilík, Miloš

    2015-01-01

    Roč. 24, č. 2 (2015), s. 80-84. ISSN 1022-1344 R&D Projects: GA ČR(CZ) GA13-02938S Institutional support: RVO:61389013 Keywords : branching exponent * branching indexes * intrinsic viscosity Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.667, year: 2014

  4. Numerical study on thermal stratification phenomenon in SCS branch pipe for APR1400

    International Nuclear Information System (INIS)

    The thermal stratification in the unisolable branch pipe for the Shutdown Cooling System (SCS) suction line for APR1400 has been studied. The vertical-horizontal branch pipe with an isolation valve at the end, and under Reactor System (RCS) operating condition is susceptible to the thermal stratification due to the stagnation flow around the isolation valve. The formation of the thermal stratification at the horizontal part of the branch line should be evaluated to determine the design consideration of thermal fatigue. Three dimensional transient analysis for the thermal stratification in a branch pipe is performed using the computational fluid dynamics code, FLUENT, to evaluate the velocity and temperature distribution. Parametric studies have been carried out to investigate the effect of the design and operating conditions. Parameters like the hot leg flow velocity, the outleakage through the isolation valve and the thermal insulation on piping wall are taken account. The analyses show that the temperature difference caused by the thermal stratification at the horizontal part of the unisolable branch pipe is not remarkable under normal operating conditions since the turbulent penetration length is developed deeply in the branch pipe due to the high velocity flow in the RCS hot leg. (author)

  5. Tau hadronic branching ratios

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    From 64492 selected \\tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \\pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \\pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \\tau-\\mu universality in hadronic decays, g_\\tau/g_\\mu \\ = \\ 1.0013 \\ \\pm \\ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \\tau decay width: R_{\\tau ,V} \\ = \\ 1.788 \\ \\pm \\ 0.025 and R_{\\tau ,A} \\ = \\ 1.694 \\ \\pm \\ 0.027. The ratio (R_{\\tau ,V} - R_{\\tau ,A}) / (R_{\\tau ,V} + R_{\\tau ,A}), equal to (2.7 \\pm 1.3) \\ \\%, is a measure of the importance of Q...

  6. DRILL BITS FOR HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Paolo Macini

    1996-12-01

    Full Text Available This paper underlines the importance of the correct drill bit application in horizontal wells. Afler the analysis of the peculiarities of horizontal wells and drainholes drilling techniques, advantages and disadvantages of the application of both roller cone and fixed cutters drill bits have been discussed. Also, a review of the potential specific featuries useful for a correct drill bit selection in horizontal small diameter holes has been highlighted. Drill bits for these special applications, whose importance is quickly increasing nowadays, should be characterised by a design capable to deliver a good penetration rate low WOB, and, at the same time, be able to withstand high RPM without premature cutting structure failure and undergauge. Formation properties will also determine the cutting structure type and the eventual specific features for additional gauge and shoulder protection.

  7. Pressure analysis for horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Spivak, D.

    1988-01-01

    This study deals with the solution for pressure response of horizontal wells in three different anisotropic media: the infinite reservoir, the limited reservoir and the reservoir with constant pressure at the outer boundaries. Pressure analyses for vertical wells in various reservoirs are abundant, but there has been no comprehensive study of pressure analysis for horizontal wells in these three media. The objectives of this work are to examine and to determine the likely effects of horizontal wells on productivity and on the integration of pressure tests. The method of images, the concept of instantaneous sources and the Newman product method have been used. Integration of the summed source functions is achieved numerically using Simpson's rule. All three solutions are semi-analytical and have been verified and validated. For the infinite reservoir the solution has been compared to a directional well of high angle, and long horizontal well responses have been compared to the solution for the uniform-flux vertical fracture. The solutions to the other two cases (for long horizontal wells) have been compared to published solutions for uniform-flux vertical fractures. New equations, new pseudo-skin factors, new type curves, and new shape factors have been generated in the course of this work. The log-log type curves can be used to determine reservoir characteristics. The influences of different well and reservoir parameters on the well productivity have been investigated and are presented to show the merits of horizontal wells. A major features of this study is that some portions are presented here for the first time.

  8. Die erhöhte horizontal Ebene / Plano horizontal plano

    OpenAIRE

    Campo Baeza, Alberto

    2011-01-01

    Artículo sobre el plano horizontal en arquitectura. Esta investigación se inscribe en la línea "Luz y gravedad". Se relacionan conceptos y obras de la historia de la arquitectura con los conceptos desarrollados en los proyectos de Alberto Campo Baeza. La revista Bauwelt está indexada en AVERY y RIBA.

  9. Branches of Opportunity

    Science.gov (United States)

    Giles, David

    2013-01-01

    As more and more New Yorkers turn to digital books, Wikipedia and other online tools for information and entertainment, there is a growing sense that the age of the public library is over. But, in reality, New York City's public libraries are more essential than ever. Far from becoming obsolete, the city's three public library systems--Brooklyn,…

  10. Identifying thermal cycling mechanisms in PWR branch line piping

    Energy Technology Data Exchange (ETDEWEB)

    Rosinski, S.T. [EPRI, Charlotte, NC (United States); Keller, J.D.; Bilanin, A.J. [Continuum Dynamics, Inc., Ewing, NJ (United States)

    2002-07-01

    Predicting the onset and the characteristics of thermal cycling in pressurized water reactor (PWR) branch line piping systems is critical to formulation of thermal fatigue screening tools. The complex nature of the underlying thermal-hydraulic phenomena, however, significantly complicates prediction using analytical models or direct numerical simulations. Instead, it is necessary to perform scaled experiments to identify the physical mechanisms and to gather data for formulation of semi-empirical models for the thermal cycling phenomena. Through the EPRI Materials Reliability Program a test program is underway to identify and develop semi-empirical correlations for the physical thermalhydraulic mechanisms that cause thermal cycling in dead-ended PWR branch line piping systems. Three series of tests are being performed in this test program: configuration tests on a representative up-horizontal (UH) branch line piping geometry, configuration tests on a representative down-horizontal (DH) branch line piping geometry, and high Reynolds number tests to assess penetration of secondary flow structures into a dead-ended branch line. Results from UH and DH configuration tests indicate that random turbulence penetration is not sufficient for thermal cycling to occur. Rather a swirling flow structure, representative of a large, 'corkscrew' vortical structure, is required for thermal cycling. Scale tests on the UH configuration have simulated cycling phenomena observed in full-scale plant data and have been used to determine parametric sensitivities in formulating a predictive model for the thermal cycling. Data indicate that the mechanism for thermal cycling in UH configurations is stochastic but scales with the leak rate from the valve. The critical dependent variables are reduced to several non-dimensional scaling curves, resulting in a semiempirical predictive model. This paper discusses the test program and the results obtained to date. Application of these

  11. Continuous-state branching processes

    CERN Document Server

    Li, Zenghu

    2012-01-01

    These notes were used in a short graduate course on branching processes the author gave in Beijing Normal University. The following main topics are covered: scaling limits of Galton--Watson processes, continuous-state branching processes, extinction probabilities, conditional limit theorems, decompositions of sample paths, martingale problems, stochastic equations, Lamperti's transformations, independent and dependent immigration processes. Some of the results are simplified versions of those in the author's book "Measure-valued branching Markov processes" (Springer, 2011). We hope these simplified results will set out the main ideas in an easy way and lead the reader to a quick access of the subject.

  12. Left bundle-branch block

    DEFF Research Database (Denmark)

    Risum, Niels; Strauss, David; Sogaard, Peter;

    2013-01-01

    The relationship between myocardial electrical activation by electrocardiogram (ECG) and mechanical contraction by echocardiography in left bundle-branch block (LBBB) has never been clearly demonstrated. New strict criteria for LBBB based on a fundamental understanding of physiology have recently...

  13. Metamorphopsia Associated with Branch Retinal Vein Occlusion

    Science.gov (United States)

    Manabe, Koichiro; Tsujikawa, Akitaka; Osaka, Rie; Nakano, Yuki; Fujita, Tomoyoshi; Shiragami, Chieko; Hirooka, Kazuyuki; Uji, Akihito; Muraoka, Yuki

    2016-01-01

    Purpose To apply M-CHARTS for quantitative measurements of metamorphopsia in eyes with acute branch retinal vein occlusion (BRVO) and to elucidate the pathomorphology that causes metamorphopsia. Methods This prospective study consisted of 42 consecutive patients (42 eyes) with acute BRVO. Both at baseline and one month after treatment with ranibizumab, metamorphopsia was measured with M-CHARTS, and the retinal morphological changes were examined with optical coherence tomography. Results At baseline, metamorphopsia was detected in the vertical and/or horizontal directions in 29 (69.0%) eyes; the mean vertical and horizontal scores were 0.59 ± 0.57 and 0.52 ± 0.67, respectively. The maximum inner retinal thickness showed no association with the M-CHARTS score, but the M-CHARTS score was correlated with the total foveal thickness (r = 0.43, p = 0.004), the height of serous retinal detachment (r = 0.31, p = 0.047), and the maximum outer retinal thickness (r = 0.36, p = 0.020). One month after treatment, both the inner and outer retinal thickness substantially decreased. However, metamorphopsia persisted in 26 (89.7%) of 29 eyes. The posttreatment M-CHARTS score was not correlated with any posttreatment morphological parameters. However, the posttreatment M-CHARTS score was weakly correlated with the baseline total foveal thickness (r = 0.35. p = 0.024) and closely correlated with the baseline M-CHARTS score (r = 0.78, p < 0.001). Conclusions Metamorphopsia associated with acute BRVO was quantified using M-CHARTS. Initial microstructural changes in the outer retina from acute BRVO may primarily account for the metamorphopsia. PMID:27123642

  14. Orphan penumbrae: Submerging horizontal fields

    CERN Document Server

    Jurcak, J; Sobotka, M

    2014-01-01

    We investigate the properties of orphan penumbrae, which are photospheric filamentary structures observed in active regions near polarity inversion lines that resemble the penumbra of regular sunspots but are not connected to any umbra. We use Hinode data from the Solar Optical Telescope to determine the properties of orphan penumbrae. Spectropolarimetric data are employed to obtain the vector magnetic field and line-of-sight velocities in the photosphere. Magnetograms are used to study the overall evolution of these structures, and G-band and Ca II H filtergrams are to investigate their brightness and apparent horizontal motions. Orphan penumbrae form between regions of opposite polarity in places with horizontal magnetic fields. Their magnetic configuration is that of $\\Omega$-shaped flux ropes. In the two cases studied here, the opposite-polarity regions approach each other with time and the whole structure submerges as the penumbral filaments disappear. Orphan penumbrae are very similar to regular penumbr...

  15. Horizontal gene transfer in plants.

    Science.gov (United States)

    Gao, Caihua; Ren, Xiaodong; Mason, Annaliese S; Liu, Honglei; Xiao, Meili; Li, Jiana; Fu, Donghui

    2014-03-01

    Horizontal gene transfer (HGT) describes the transmission of genetic material across species boundaries. HGT often occurs in microbic and eukaryotic genomes. However, the pathways by which HGTs occur in multicellular eukaryotes, especially in plants, are not well understood. We systematically summarized more than ten possible pathways for HGT. The intimate contact which frequently occurs in parasitism, symbiosis, pathogen, epiphyte, entophyte, and grafting interactions could promote HGTs between two species. Besides these direct transfer methods, genes can be exchanged with a vector as a bridge: possible vectors include pollen, fungi, bacteria, viruses, viroids, plasmids, transposons, and insects. HGT, especially when involving horizontal transfer of transposable elements, is recognized as a significant force propelling genomic variation and biological innovation, playing an important functional and evolutionary role in both eukaryotic and prokaryotic genomes. We proposed possible mechanisms by which HGTs can occur, which is useful in understanding the genetic information exchange among distant species or distant cellular components. PMID:24132513

  16. Horizontal gene transfer in fungi

    OpenAIRE

    Fitzpatrick, David A.

    2011-01-01

    Horizontal gene transfer (HGT) is frequently observed in prokaryotes and until recently was assumed to be of limited importance to eukaryotes. However, there is an increasing body of evidence to suggest that HGT is an important mechanism in eukaryotic genome evolution, particularly in unicellular organisms. The transfer of individual genes, gene clusters or entire chromosomes can have significant impacts on niche specification, disease emergence or shift in metabolic capabil...

  17. Horizontal mergers and product quality

    OpenAIRE

    Brekke, Kurt Richard; Siciliani, Luigi; Straume, Odd Rune

    2014-01-01

    Using a spatial competition framework with three ex ante identical firms, we study the effects of a horizontal merger on quality, price and welfare. The merging firms always reduce quality. They also increase prices if demand responsiveness to quality is sufficiently low. The non-merging firm, on the other hand, always responds by increasing both quality and prices. Overall, a merger leads to higher average prices and quality in the market. The welfare implications of a merger are not clea...

  18. Horizontally oriented plates in clouds

    CERN Document Server

    Bréon, François-Marie

    2011-01-01

    Horizontally oriented plates in clouds generate a sharp specular reflectance signal in the glint direction, often referred to as "subsun". This signal (amplitude and width) may be used to analyze the relative area fraction of oriented plates in the cloud top layer and their characteristic tilt angle to the horizontal. We make use of spaceborne measurements from the POLDER instrument to provide a statistical analysis of these parameters. More than half of the clouds show a detectable maximum reflectance in the glint direction, although this maximum may be rather faint. The typical effective fraction (area weighted) of oriented plates in clouds lies between 10-3 and 10-2. For those oriented plates, the characteristic tilt angle is less than 1 degree in most cases. These low fractions imply that the impact of oriented plates on the cloud albedo is insignificant. The largest proportion of clouds with horizontally oriented plates is found in the range 500-700 hPa, in agreement with typical in situ observation of p...

  19. Explicit horizontal open books on some plumbings

    OpenAIRE

    Etgü, Tolga; Ozbagci, Burak

    2005-01-01

    We describe explicit open books on arbitrary plumbings of oriented circle bundles over closed oriented surfaces. We show that, for a non-positive plumbing, the open book we construct is horizontal and the corresponding compatible contact structure is also horizontal and Stein fillable. In particular, we describe horizontal open books on some Seifert fibered 3--manifolds. As another application we describe horizontal open books isomorphic to Milnor open books for some complex surface singulari...

  20. Horizontal well length optimization considering wellbore hydraulics

    OpenAIRE

    Syed, Adnan

    2014-01-01

    Horizontal wells covering entire length of the reservoirs are not economically suitable. Frictional pressure drops increases with the increase in well length and flow rates. Optimal Horizontal length is estimated through economic analysis i.e. Net present Value of the project (NPV). Well construction costs including incremental costs of drilling horizontal section, friction losses in horizontal section, Hydrocarbon prices and Drainage area affect NPV. This thesis work estimates NPV and Produc...

  1. The Na-O anticorrelation in horizontal branch stars. II. NGC1851

    CERN Document Server

    Gratton, R G; Carretta, E; Bragaglia, A; D'Orazi, V; Momany, Y Al; Sollima, A; Salaris, M; Cassisi, S

    2012-01-01

    We studied the Na-O anti-correlation from moderately high resolution spectra for 35 stars on the blue HB (BHB), one RR Lyrae, and 55 stars are on the red HB (RHB) of NGC1851. We also derived abundances for He and N in BHB stars, and Ba and upper limits for N in RHB stars. The RHB stars clearly separate into two groups: the vast majority are O-rich and Na-poor, while about 10-15% are Na-rich and moderately O-poor. Most Na-rich RHB stars are also Ba-rich and there is an overall correlation between Na and Ba abundances within the RHB. The group of Ba-rich RHB stars resides on the warmer edge and includes ~10% of the RHB stars. We propose that they are the descendant of the stars on the RGB sequence with very red v-y colour. This sequence is known also to consist of Ba and perhaps CNO-rich stars. However, the upper limit we obtain for N ([N/Fe]<1.55) for one of the Ba-rich stars coupled with the low C-abundances for RGB Ba-rich stars from the literature suggests that the total CNO might not be particularly hig...

  2. THE RR LYRAE VARIABLES AND HORIZONTAL BRANCH OF NGC 6656 (M22) {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Kunder, Andrea; Walker, Alistair R.; Paredes Alvarez, Leonardo [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Stetson, Peter B. [Dominion Astrophysical Observatory, NRC-Herzberg, National Research Council, Victoria BC, V9E 2E7 (Canada); Cassisi, Santi [INAF-Osservatorio Astronomico di Collurania, Via M. Maggini, I-64100 Teramo (Italy); Layden, Andrew [Bowling Green State University, Bowling Green, OH 43403 (United States); Bono, Giuseppe [Dipartimento di Fisica, Universita di Roma Tor Vergata, Rome (Italy); Catelan, Márcio [Pontificia Universidad Católica de Chile, Departamento de Astronomía y Astrofísica, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago (Chile); Clem, James L. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Matsunaga, Noriyuki [Department of Astronomy, School of Science, The University of Tokyo (Japan); Salaris, Maurizio [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Lee, Jae-Woo [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Chaboyer, Brian, E-mail: akunder@ctio.noao.edu, E-mail: mcatelan@astro.puc.cl [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

    2013-11-01

    The first calibrated broadband UBVI time-series photometry is presented for the RR Lyrae variable stars in NGC 6656 (M22), with observations spanning a range of 22 years. We have also redetermined the variability types and periods for the RR Lyrae stars identified previously by photographic observations, revising the number of fundamental-mode RR Lyrae variables (RR0) to 10 and the number of first-overtone variables (RR1) to 16. The mean periods of the RR0 and RR1 variables are (P) {sub RR0} = 0.66 ± 0.02 days and (P) {sub RR1} = 0.33 ± 0.01 days, respectively, supporting an Oosterhoff II classification for the cluster. The number ratio of RR1-type to all RR-type variables is N {sub 1}/N{sub RR} = 0.61, also consistent with an Oosterhoff II designation. Both the RR Lyrae stars' minimum light colors and the blue edge of the RR Lyrae instability strip suggest E( B – – V) = 0.36 ± 0.02 mag toward M22. Regarding the HB morphology of M22, we find (B-R)/(B+V+R) = +0.97 ± 0.1 and at least one ''gap'' located in an unusual part of the blue HB, in the middle of the so-called hot HB stars.

  3. Chemical composition of red horizontal branch stars in the thick disk of the Galaxy

    CERN Document Server

    Tautvaisiene, G; Tuominen, I; Ilyin, I V

    2001-01-01

    High-resolution spectra of 13 core helium-burning stars in the thick disk of the Galaxy have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 22 chemical elements. Abundances of carbon were studied using the C_2 Swan (0,1) band head at 5635.5 A. The wavelength interval 7980-8130 A with strong CN features was analysed in order to determine nitrogen abundances and 12C/13C isotope ratios. The oxygen abundances were determined from the O I line at 6300 A. Abundances in the investigated stars suggest that carbon is depleted by about 0.3 dex, nitrogen is enhanced by more than 0.4 dex and oxygen is unaltered. The 12C/13C ratios are lowered and lie between values 3 and 7 which is in agreement with "cool bottom processing" predictions (Boothroyd & Sackmann 1999). The C/N ratios in the investigated stars are lowered to values between 0.7 and 1.2 which is less than present day theoretical predictions and call for further studies of stellar mixing processes....

  4. THE RR LYRAE VARIABLES AND HORIZONTAL BRANCH OF NGC 6656 (M22) ,

    International Nuclear Information System (INIS)

    The first calibrated broadband UBVI time-series photometry is presented for the RR Lyrae variable stars in NGC 6656 (M22), with observations spanning a range of 22 years. We have also redetermined the variability types and periods for the RR Lyrae stars identified previously by photographic observations, revising the number of fundamental-mode RR Lyrae variables (RR0) to 10 and the number of first-overtone variables (RR1) to 16. The mean periods of the RR0 and RR1 variables are (P) RR0 = 0.66 ± 0.02 days and (P) RR1 = 0.33 ± 0.01 days, respectively, supporting an Oosterhoff II classification for the cluster. The number ratio of RR1-type to all RR-type variables is N 1/NRR = 0.61, also consistent with an Oosterhoff II designation. Both the RR Lyrae stars' minimum light colors and the blue edge of the RR Lyrae instability strip suggest E( B – – V) = 0.36 ± 0.02 mag toward M22. Regarding the HB morphology of M22, we find (B-R)/(B+V+R) = +0.97 ± 0.1 and at least one ''gap'' located in an unusual part of the blue HB, in the middle of the so-called hot HB stars

  5. The RR Lyrae variables and Horizontal Branch of NGC6656 (M22)

    CERN Document Server

    Kunder, Andrea; Cassisi, Santi; Layden, Andrew; Bono, Giuseppe; Catelan, Marcio; Walker, Alistair R; Alvarez, Leonardo Paredes; Clem, James L; Matsunaga, Noriyuki; Salaris, Maurizio; Lee, Jae-Woo; Chaboyer, Brian C

    2013-01-01

    The first calibrated broadband UBVI time-series photometry is presented for the RR Lyrae variable stars in NGC6656 (M22), with observations spanning a range of twenty-two years. We have also redetermined the variability types and periods for the RR Lyrae stars identified previously by photographic observations, revising the number of fundamental-mode RR Lyrae variables (RR0) to 10 and the number of first-overtone variables (RR1) to 16. The mean periods of the RR0 and RR1 variables are _{RR0}=0.66 \\pm 0.02 d and _{RR1}=0.33 \\pm 0.01 d, respectively, supporting an Oosterhoff II classification for the cluster. The number ratio of RR1- to all RR-type variables is N_1/N_{RR}=0.61, also consistent with an Oosterhoff II designation. Both the RR Lyrae stars' minimum light colors and the blue edge of the RR Lyrae instability strip suggest E(B-V)=0.36 \\pm 0.02 mag toward M22. Regarding the HB morphology of M22, we find (B-R)/(B+V+R)=+0.97 \\pm 0.1 and at least one "gap" located in an unusual part of the blue HB, in the ...

  6. The Na-O anticorrelation in horizontal branch stars. IV. M22

    CERN Document Server

    Gratton, R G; Sollima, A; Carretta, E; Bragaglia, A; Momany, Y; D'Orazi, V; Cassisi, S; Salaris, M

    2014-01-01

    We obtained high-resolution spectra for 94 candidate stars belonging to the HB of M22 with FLAMES. The HB stars we observed span a restricted temperature range (7,800

  7. 1969 TO 2010: MULTICOLOR PHOTOMETRIC OBSERVATIONS OF POPULATION II FIELD HORIZONTAL-BRANCH STARS

    Directory of Open Access Journals (Sweden)

    A. G. Davis Philip

    2011-01-01

    then observed photometrically. New FHB stars could be identified by their large c indices, caused by their greater (u ¿ b colors. Later four new filters were added (U, V , B, S. With Richard Boyle of the Vatican Observatory we observed on Mt. Graham (Arizona on the Vatican Advanced Technology Telescope. We are making follow-up observations of the new FHB stars found.

  8. Multiple pathways regulate shoot branching

    Directory of Open Access Journals (Sweden)

    Catherine eRameau

    2015-01-01

    Full Text Available Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TCP transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply.

  9. Bubble shape in horizontal and near horizontal intermittent flow

    International Nuclear Information System (INIS)

    Highlights: • The bubble shapes in intermittent flows are presented experimentally. • The nose-tail inversion phenomenon appears at a low Froude number in downward pipe. • Transition from plug to slug flow occurs when the bubble tail changes from staircase pattern to hydraulic jump. - Abstract: This paper presents an experimental study of the shape of isolated bubbles in horizontal and near horizontal intermittent flows. It is found that the shapes of the nose and body of bubble depend on the Froude number defined by gas/liquid mixture velocity in a pipe, whereas the shape of the back of bubble region depends on both the Froude number and bubble length. The photographic studies show that the transition from plug to slug flow occurs when the back of the bubble changes from staircase pattern to hydraulic jump with the increase of the Froude number and bubble length. The effect of pipe inclination on characteristics of bubble is significant: The bubble is inversely located in a downwardly inclined pipe when the Froude number is low, and the transition from plug flow to slug flow in an upward inclined pipe is more ready to occur compared with that in a downwardly inclined pipe

  10. Computer simulation of long-chain branching and branching indexes

    Czech Academy of Sciences Publication Activity Database

    Netopilík, Miloš

    Vienna : University of Vienna, 2014. s. 22. [International Conference on Polymer Behaviour /6./. 22.09.2014-26.09.2014, Vienna] R&D Projects: GA ČR(CZ) GA13-02938S Institutional support: RVO:61389013 Keywords : branching indexes * intrinsic viscosity * radius of gyration Subject RIV: CD - Macromolecular Chemistry

  11. Progressive micrographia shown in horizontal, but not vertical, writing in Parkinson's disease.

    Science.gov (United States)

    Ma, Hui-Ing; Hwang, Wen-Juh; Chang, Shao-Hsia; Wang, Tsui-Ying

    2013-01-01

    All published studies on micrographia, a diminution of letter size, examine handwriting in the horizontal direction. Writing horizontally typically requires increased wrist extension as handwriting progresses from left to right. Chinese characters, however, can be written not only horizontally from left to right, but also vertically from top to bottom. We examined the effect of handwriting direction on character size and stroke length. Fifteen participants with Parkinson's disease (PD) and 15 age-matched controls wrote the same Chinese characters both horizontally and vertically. Handwriting performance was recorded with a digitizing tablet, and a custom-written computer program was used to provide objective data about character size and stroke length. The PD group had a linear decrease in overall character size and horizontal strokes along the writing sequence in the horizontal direction, but not in the vertical direction. The controls had shorter horizontal strokes in the horizontal than the vertical direction, but there was no progressive shortening of stroke length along the writing sequence. The results suggest that traditionally reported progressive micrographia in horizontal writing may not be generalizable to vertical writing. The observed decrease of handwriting size in the horizontal direction suggests that micrographia in PD may be associated with wrist extension. For clinical implications, patients may mitigate their micrographia by changing handwriting direction. PMID:23242350

  12. Environmental restoration using horizontal wells

    International Nuclear Information System (INIS)

    This paper reports that under sponsorship from the U.S. Department of Energy, technical personnel from the Savannah River Laboratory and other DOE laboratories, universities and private industry have completed a full scale demonstration of environmental remediation using horizontal wells. The test successfully removed approximately 7250 kg of contaminants. A large amount of characterization and monitoring data was collected to aid in interpretation of the test and to provide the information needed for future environmental restorations that employ directionally drilled wells as extraction or delivery systems

  13. [Variations of the celiac trunk branches in the fetus].

    Science.gov (United States)

    Bordei, P; Antohe, D S

    2002-09-01

    The study was performed on 60 human foetuses, aged between 4 to 9 months, using as methods dissection and plastic and contrast substances injection. We studied the celiac trunk in what concerns the division into its terminal branches, insisting on the possible morphological variations, some rare collateral branches starting from the common arterial trunk, the dimensional relations between the branches at their origin and the level of the celiac trunk origin from the aorta, in relation with the vertebral column, the diaphragmatic passage of the aorta and with the superior mesenteric artery. We also assessed the dimensional relations (calibers at origin) between the branches of the celiac trunk. Ass possible variations of the division of the celiac trunk, we assessed: gastro-hepatic trunk, with the splenic artery directly from the aorta or from the hepatic artery; gastro-splenic trunk, with the hepatic artery originating from the aorta; hepato-splenic trunk, with origin of the left gastric artery either directly from the aorta or from the hepatic artery. Rare variations: celiaco-mesenteric trunk; two arterial trunks, hepato-splenic and hepato-gastric; separate aortic origin for all three "classic" branches of the celiac trunk; two hepatic arteries, one from the celiac trunk and the other from the aorta or superior mesenteric artery; celiac trunk that divides into several terminal branches; one or two suprarenal arteries originating from the celiac trunk. PMID:12572348

  14. Soils of Walker Branch Watershed

    Energy Technology Data Exchange (ETDEWEB)

    Lietzke, D.A.

    1994-01-01

    The soil survey of Walker Branch Watershed (WBW) utilized the most up-to-date knowledge of soils, geology, and geohydrology in building the soils data base needed to reinterpret past research and to begin new research in the watershed. The soils of WBW were also compared with soils mapped elsewhere along Chestnut Ridge on the Oak Ridge Reservation to (1) establish whether knowledge obtained elsewhere could be used within the watershed, (2) determine whether there were any soils restricted to the watershed, and (3) evaluate geologic formation lateral variability. Soils, surficial geology, and geomorphology were mapped at a scale of 1:1200 using a paper base map having 2-ft contour intervals. Most of the contours seemed to reasonably represent actual landform configurations, except for dense wooded areas. For example, the very large dolines or sinkholes were shown on the contour base map, but numerous smaller ones were not. In addition, small drainageways and gullies were often not shown. These often small but important features were located approximately as soil mapping progressed. WBW is underlain by dolostones of the Knox Group, but only a very small part of the surface area contains outcroppings of rock and most outcrops were located in the lower part. Soil mapping revealed the presence of both ancient alluvium and ancient colluvium deposits, not recognized in previous soil surveys, that have been preserved in high-elevation stable portions of present-day landforms. An erosional geomorphic process of topographic inversion requiring several millions of years within the Pleistocene is necessary to bring about the degree of inversion that is expressed in the watershed. Indeed, some of these ancient alluvial and colluvial remnants may date back into the Tertiary. Also evident in the watershed, and preserved in the broad, nearly level bottoms of dolines, are multiple deposits of silty material either devoid or nearly devoid of coarse fragments. Recent research

  15. Horizontal gene transfer in chromalveolates

    Directory of Open Access Journals (Sweden)

    Bhattacharya Debashish

    2007-09-01

    Full Text Available Abstract Background Horizontal gene transfer (HGT, the non-genealogical transfer of genetic material between different organisms, is considered a potentially important mechanism of genome evolution in eukaryotes. Using phylogenomic analyses of expressed sequence tag (EST data generated from a clonal cell line of a free living dinoflagellate alga Karenia brevis, we investigated the impact of HGT on genome evolution in unicellular chromalveolate protists. Results We identified 16 proteins that have originated in chromalveolates through ancient HGTs before the divergence of the genera Karenia and Karlodinium and one protein that was derived through a more recent HGT. Detailed analysis of the phylogeny and distribution of identified proteins demonstrates that eight have resulted from independent HGTs in several eukaryotic lineages. Conclusion Recurring intra- and interdomain gene exchange provides an important source of genetic novelty not only in parasitic taxa as previously demonstrated but as we show here, also in free-living protists. Investigating the tempo and mode of evolution of horizontally transferred genes in protists will therefore advance our understanding of mechanisms of adaptation in eukaryotes.

  16. Horizontal versus vertical plate motions

    Directory of Open Access Journals (Sweden)

    M. Cuffaro

    2006-07-01

    Full Text Available We review both present and past motions at major plate boundaries, which have the horizontal component in average 10 to 100 times faster (10–100 mm/yr than the vertical component (0.01–1 mm/yr in all geodynamic settings. The steady faster horizontal velocity of the lithosphere with respect to the upward or downward velocities at plate boundaries supports dominating tangential forces acting on plates. This suggests a passive role of plate boundaries with respect to far field forces determining the velocity of plates. The forces acting on the lithosphere can be subdivided in coupled and uncoupled, as a function of the shear at the lithosphere base. Higher the asthenosphere viscosity, more significant should be the coupled forces, i.e., the mantle drag and the trench suction. Lower the asthenosphere viscosity, more the effects of uncoupled forces might result determinant, i.e., the ridge push, the slab pull and the tidal drag. Although a combination of all forces acting on the lithosphere is likely, the decoupling between lithosphere and mantle suggests that a torque acts on the lithosphere independently of the mantle drag. Slab pull and ridge push are candidates for generating this torque, but, unlike these boundary forces, the advantage of the tidal drag is to be a volume force, acting simultaneously on the whole plates, and being the decoupling at the lithosphere base controlled by lateral variations in viscosity of the low-velocity layer.

  17. Orphan penumbrae: Submerging horizontal fields

    Science.gov (United States)

    Jurčák, J.; Bellot Rubio, L. R.; Sobotka, M.

    2014-04-01

    Aims: We investigate the properties of orphan penumbrae, which are photospheric filamentary structures observed in active regions near polarity inversion lines that resemble the penumbra of regular sunspots but are not connected to any umbra. Methods: We use Hinode data from the Solar Optical Telescope to determine the properties of orphan penumbrae. Spectropolarimetric data are employed to obtain the vector magnetic field and line-of-sight velocities in the photosphere. Magnetograms are used to study the overall evolution of these structures, and G-band and Ca ii H filtergrams are to investigate their brightness and apparent horizontal motions. Results: Orphan penumbrae form between regions of opposite polarity in places with horizontal magnetic fields. Their magnetic configuration is that of Ω-shaped flux ropes. In the two cases studied here, the opposite-polarity regions approach each other with time and the whole structure submerges as the penumbral filaments disappear. Orphan penumbrae are very similar to regular penumbrae, including the existence of strong gas flows. Therefore, they could have a similar origin. The main difference between them is the absence of a "background" magnetic field in orphan penumbrae. This could explain most of the observed differences. Conclusions: The fast flows we detect in orphan penumbrae may be caused by the siphon flow mechanism. Based on the similarities between orphan and regular penumbrae, we propose that the Evershed flow is also a manifestation of siphon flows. A movie attached to Fig. 11 is available in electronic form at http://www.aanda.org

  18. NCI: DCTD: Biometric Research Branch

    Science.gov (United States)

    The Biometric Research Branch (BRB) is the statistical and biomathematical component of the Division of Cancer Treatment, Diagnosis and Centers (DCTDC). Its members provide statistical leadership for the national and international research programs of the division in developmental therapeutics, developmental diagnostics, diagnostic imaging and clinical trials.

  19. Branching of keratin intermediate filaments.

    Science.gov (United States)

    Nafeey, Soufi; Martin, Ines; Felder, Tatiana; Walther, Paul; Felder, Edward

    2016-06-01

    Keratin intermediate filaments (IFs) are crucial to maintain mechanical stability in epithelial cells. Since little is known about the network architecture that provides this stiffness and especially about branching properties of filaments, we addressed this question with different electron microscopic (EM) methods. Using EM tomography of high pressure frozen keratinocytes, we investigated the course of several filaments in a branching of a filament bundle. Moreover we found several putative bifurcations in individual filaments. To verify our observation we also visualized the keratin network in detergent extracted keratinocytes with scanning EM. Here bifurcations of individual filaments could unambiguously be identified additionally to bundle branchings. Interestingly, identical filament bifurcations were also found in purified keratin 8/18 filaments expressed in Escherichia coli which were reassembled in vitro. This excludes that an accessory protein contributes to the branch formation. Measurements of the filament cross sectional areas showed various ratios between the three bifurcation arms. This demonstrates that intermediate filament furcation is very different from actin furcation where an entire new filament is attached to an existing filament. Instead, the architecture of intermediate filament bifurcations is less predetermined and hence consistent with the general concept of IF formation. PMID:27039023

  20. Multi-Level Flow Branching

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav

    Praha: UTAM AV ČR, 2006 - (Náprstek, J.; Fischer, C.), s. 380-381 ISBN 80-86246-27-2. [Engineering mechanics 2006 : national conference with international participation. Svratka (CZ), 15.05.2006-18.05.2006] Institutional research plan: CEZ:AV0Z20760514 Keywords : branching * respiratory system * aortic system * microfluidics Subject RIV: BK - Fluid Dynamics

  1. Cash efficiency for bank branches.

    Science.gov (United States)

    Cabello, Julia García

    2013-01-01

    Bank liquidity management has become a major issue during the financial crisis as liquidity shortages have intensified and have put pressure on banks to diversity and improve their liquidity sources. While a significant strand of the literature concentrates on wholesale liquidity generation and on the alternative to deposit funding, the management of an inventory of cash holdings within the banks' branches is also a relevant issue as any significant improvement in cash management at the bank distribution channels may have a positive effect in reducing liquidity tensions. In this paper, we propose a simple programme of cash efficiency for the banks' branches, very easy to implement, which conform to a set of instructions to be imposed from the bank to their branches. This model proves to significantly reduce cash holdings at branches thereby providing efficiency improvements in liquidity management. The methodology we propose is based on the definition of some stochastic processes combined with renewal processes, which capture the random elements of the cash flow, before applying suitable optimization programmes to all the costs involved in cash movements. The classical issue of the Transaction Demand for the Cash and some aspects of Inventory Theory are also present. Mathematics Subject Classification (2000) C02, C60, E50. PMID:24010026

  2. Fluid Flow at Branching Junctions

    OpenAIRE

    Sochi, Taha

    2013-01-01

    The flow of fluids at branching junctions plays important kinematic and dynamic roles in most biological and industrial flow systems. The present paper highlights some key issues related to the flow of fluids at these junctions with special emphasis on the biological flow networks particularly blood transportation vasculature.

  3. Risk Factor Assessment Branch (RFAB)

    Science.gov (United States)

    The Risk Factor Assessment Branch (RFAB) focuses on the development, evaluation, and dissemination of high-quality risk factor metrics, methods, tools, technologies, and resources for use across the cancer research continuum, and the assessment of cancer-related risk factors in the population.

  4. The Ages of 55 Globular Clusters as Determined Using an Improved delta V_TO^HB Method Along with Color-Magnitude Diagram Constraints, and Their Implications for Broader Issues

    CERN Document Server

    Vandenberg, Don A; Leaman, Ryan; Casagrande, Luca

    2013-01-01

    Ages have been derived for 55 globular clusters (GCs) from overlays of isochrones onto the turnoff photometry, assuming distances based on fits of zero-age horizontal branch (ZAHB) models to the lower bound of the observed distributions of HB stars. The error bar arising just from the "fitting" of ZAHBs and isochrones is ~ +/- 0.25 Gyr, while that associated with distance and chemical abundance uncertainties is ~ +/- 1.5-2 Gyr. Ages vary from mean values of ~12.5 Gyr at [Fe/H] -1.0. At intermediate metallicities, the age-metallicity relation (AMR) appears to be bifurcated: one branch apparently contains clusters with disk-like kinematics, whereas the other branch is populated by clusters with halo-type orbits. There is no apparent dependence of age on Galactocentric distance (R_G) nor is there a clear correlation of HB type with age. Subtle variations in the subgiant branch (SGB) slopes of [Fe/H] < -1.5 GCs are tentatively attributed to helium abundance differences. Curiously, GCs with steep "M13-like" SG...

  5. Propagação vegetativa do Bambu imperial (Bambusa vulgaris Schrad. var. vittata A. et C. Riv. Propagation of Bambusa vulgaris schrad. var. vittata a. & c. riv. by branch cuttings and culm setions.

    Directory of Open Access Journals (Sweden)

    Júlio César Medina

    1962-01-01

    Full Text Available Êste estudo trata da multiplicação vegetativa do bambu imperial, por meio de estacas de ramos e toletes de côlmo. Teve, por finalidade, verificar a praticobilidade desses processos em substituição ao método ortodoxo da subdivisão de touceiros, usado pora sua propagação. Os resultados obtidos mostram que ambos os processos são bastante eficientes, desde que sejam respeitadas os seguintes regras básicas: 1 utilizar apenas 05 bases de ramos para fornecimento das estacas; 2 plantar os toletes de côlmo em posição horizontal. Foram obtidas, dessa maneira, os seguintes porcentagens de enraizamento: 70,5% para estacas de base de ramo e 99% para toletes de côlmo.The common method of propagating Bambusa vulgaris Schrad. var. vittata A. et C. Riv., like other clump bamboos, is by division. This method, although quite effective, has the disadvantage of being economically impractical to supply commercial demands of planting material for large scale bamboo plantations. This study deals with the assexual propagation of this bamboo species by branch cuttings and culm sections as propagating material, to overcome the disadvantage of propagation by clump division. Branch cuttings and culm sections were obtained from 80 culms, 40 being about I year old and 40 about 3 years old. Two hundred branch cuttings and one hundred culm sections were taken for each culm age group and divided into five subgroups for treatment or not with the following root-promoting substances: Trilone (2,4-D, Dieradix D, Dieradix MD, and alpha-naphthylacetic acid. Two types of branch cuttings were taken from the middle and top sections of each culm age group: a the basal enlarged portion of the branch, including 3 nodes and 2 internodes, besides a little portion of the culm wood attached to the base; b the next portion of the same branch, including 3 nodes and 2 internodes. So, there were 10 branch cuttings in each treatment including the untreated check, for each culm age

  6. Branching processes in disease epidemics

    Science.gov (United States)

    Singh, Sarabjeet

    Branching processes have served as a model for chemical reactions, biological growth processes and contagion (of disease, information or fads). Through this connection, these seemingly different physical processes share some common universalities that can be elucidated by analyzing the underlying branching process. In this thesis, we focus on branching processes as a model for infectious diseases spreading between individuals belonging to different populations. The distinction between populations can arise from species separation (as in the case of diseases which jump across species) or spatial separation (as in the case of disease spreading between farms, cities, urban centers, etc). A prominent example of the former is zoonoses -- infectious diseases that spill from animals to humans -- whose specific examples include Nipah virus, monkeypox, HIV and avian influenza. A prominent example of the latter is infectious diseases of animals such as foot and mouth disease and bovine tuberculosis that spread between farms or cattle herds. Another example of the latter is infectious diseases of humans such as H1N1 that spread from one city to another through migration of infectious hosts. This thesis consists of three main chapters, an introduction and an appendix. The introduction gives a brief history of mathematics in modeling the spread of infectious diseases along with a detailed description of the most commonly used disease model -- the Susceptible-Infectious-Recovered (SIR) model. The introduction also describes how the stochastic formulation of the model reduces to a branching process in the limit of large population which is analyzed in detail. The second chapter describes a two species model of zoonoses with coupled SIR processes and proceeds into the calculation of statistics pertinent to cross species infection using multitype branching processes. The third chapter describes an SIR process driven by a Poisson process of infection spillovers. This is posed as a

  7. Branching problems of unitary representations

    OpenAIRE

    Kobayashi, Toshiyuki

    2003-01-01

    The irreducible decomposition of a unitary representation often contains continuous spectrum when restricted to a non-compact subgroup. The author singles out a nice class of branching problems where each irreducible summand occurs discretely with finite multiplicity (admissible restrictions). Basic theory and new perspectives of admissible restrictions are presented from both analytic and algebraic view points. We also discuss some applications of admissible restrictions to modular varieties...

  8. Cash efficiency for bank branches

    OpenAIRE

    Cabello, Julia García

    2013-01-01

    Bank liquidity management has become a major issue during the financial crisis as liquidity shortages have intensified and have put pressure on banks to diversity and improve their liquidity sources. While a significant strand of the literature concentrates on wholesale liquidity generation and on the alternative to deposit funding, the management of an inventory of cash holdings within the banks’ branches is also a relevant issue as any significant improvement in cash management at the bank ...

  9. Solid State Photovoltaic Research Branch

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    This report summarizes the progress of the Solid State Photovoltaic Research Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30,l 1989. Six technical sections of the report cover these main areas of SERIs in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Laser Raman and Luminescence Spectroscopy. Sections have been indexed separately for inclusion on the data base.

  10. Creep of welded branched pipes

    OpenAIRE

    Rayner, Glen

    2004-01-01

    Creep failure of welds in high-temperature power plant steam piping systems is known to be a potential cause of plant failure. Creep behaviour of plain pipes with circumferential welds and cross-weld specimens have received fairly extensive attention. However, research into the creep behaviour of welded thick-walled branched steam pipes has received less attention. Consequently, this thesis addresses improving the understanding of the creep behaviour for this type of geometry. Numerical and a...

  11. Interactions between Axillary Branches of Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Veronica Ongaro; Katherine Bainbridge; Lisa Williamson; Ottoline Leyser

    2008-01-01

    Studies of apical dominance have benefited greatly from two-branch assays in pea and bean,in which the shoot system is trimmed back to leave only two active cotyledonary axillary branches.In these two-branch shoots,a large body of evidence shows that one actively growing branch is able to inhibit the growth of the other,prompting studies on the nature of the inhibitory signals,which are still poorly understood.Here,we describe the establishment of two-branch assays in Arabidopsis,using consecutive branches on the bolting stem.As with the classical studies in pea and bean,these consecutive branches are able to inhibit one another's growth.Not only can the upper branch inhibit the lower branch,but also the lower branch can inhibit the upper branch,illustrating the bi-directional action of the inhibitory signals.Using mutants,we show that the inhibition is partially dependent on the MAX pathway and that while the inhibition is clearly transmitted across the stem from the active to the inhibited branch,the vascular connectivity of the two branches is weak,and the MAX pathway is capable of acting unilaterally in the stem.

  12. Convergence substitution for paralysed horizontal gaze.

    OpenAIRE

    Beigi, B.; O'Keeffe, M; Logan, P; Eustace, P.

    1995-01-01

    Three patients with paralysed horizontal gaze are presented. Involuntary use of convergence to assist horizontal gaze was noted as a late feature. All patients showed (1) unilateral or bilateral horizontal gaze palsy (two patients had one and a half syndrome, the other had bilateral nuclear sixth nerve palsies), (2) adduction of both eyes on attempted gaze into the paralysed field, (3) miosis which coincided with adduction. Convergence substitution should be considered in the differential dia...

  13. Spray controller for horizontal boom movements compensation

    OpenAIRE

    El Bahir, Loussain; Lebeau, Frédéric; Destain, Marie-France; Kinnaert; Hanus, Raymond

    2002-01-01

    Longitudinal spray distribution is mainly affected by the horizontal speed variations of the nozzles. Manufacturers classically try to reduce unwanted nozzles movements using horizontal boom suspension but these methods show performance and price limitations. The purpose of this paper is to propose a spray controller aiming to compensate the effect of the horizontal boom movements on the spray distribution besides the effect of tractor speed variations. The controller is based on ...

  14. Branching processes and neutral evolution

    CERN Document Server

    Taïb, Ziad

    1992-01-01

    The Galton-Watson branching process has its roots in the problem of extinction of family names which was given a precise formulation by F. Galton as problem 4001 in the Educational Times (17, 1873). In 1875, an attempt to solve this problem was made by H. W. Watson but as it turned out, his conclusion was incorrect. Half a century later, R. A. Fisher made use of the Galton-Watson process to determine the extinction probability of the progeny of a mutant gene. However, it was J. B. S. Haldane who finally gave the first sketch of the correct conclusion. J. B. S. Haldane also predicted that mathematical genetics might some day develop into a "respectable branch of applied mathematics" (quoted in M. Kimura & T. Ohta, Theoretical Aspects of Population Genetics. Princeton, 1971). Since the time of Fisher and Haldane, the two fields of branching processes and mathematical genetics have attained a high degree of sophistication but in different directions. This monograph is a first attempt to apply the current sta...

  15. System for Estimating Horizontal Velocity During Descent

    Science.gov (United States)

    Johnson, Andrew; Cheng, Yang; Wilson, Reg; Goguen, Jay; Martin, Alejandro San; Leger, Chris; Matthies, Larry

    2007-01-01

    The descent image motion estimation system (DIMES) is a system of hardware and software, designed for original use in estimating the horizontal velocity of a spacecraft descending toward a landing on Mars. The estimated horizontal velocity is used in generating rocket-firing commands to reduce the horizontal velocity as part of an overall control scheme to minimize the landing impact. DIMES can also be used for estimating the horizontal velocity of a remotely controlled or autonomous aircraft for purposes of navigation and control.

  16. Workshop on Branching Processes and Their Applications

    CERN Document Server

    Gonzalez Velasco, Miguel; Martinez, Rodrigo; Molina, Manuel

    2010-01-01

    Contains papers presented at the Workshop on Branching Processes and Their Applications (WBPA09), held in Badajoz, Spain, April 20-23, 2009, which deal with theoretical and practical aspects of branching process theory

  17. Mechanical properties of branched actin filaments

    CERN Document Server

    Razbin, Mohammadhosein; Benetatos, Panayotis; Zippelius, Annette

    2015-01-01

    Cells moving on a two dimensional substrate generate motion by polymerizing actin filament networks inside a flat membrane protrusion. New filaments are generated by branching off existing ones, giving rise to branched network structures. We investigate the force-extension relation of branched filaments, grafted on an elastic structure at one end and pushing with the free ends against the leading edge cell membrane. Single filaments are modeled as worm-like chains, whose thermal bending fluctuations are restricted by the leading edge cell membrane, resulting in an effective force. Branching can increase the stiffness considerably; however the effect depends on branch point position and filament orientation, being most pronounced for intermediate tilt angles and intermediate branch point positions. We describe filament networks without cross-linkers to focus on the effect of branching. We use randomly positioned branch points, as generated in the process of treadmilling, and orientation distributions as measur...

  18. The Effects of a Branch Campus

    Science.gov (United States)

    Lien, Donald; Wang, Yaqin

    2012-01-01

    We examine the effects of a branch campus on the social welfare of the host country and the foreign university. Overall, we find that a branch campus increases both the domestic social welfare (measured by the aggregate student utility) and the tuition revenue of the foreign university. The effect of a branch campus on the brain drain is…

  19. Horizontal drilling assessment in Western Canada

    International Nuclear Information System (INIS)

    The first horizontal well was drilled in Saskatchewan in 1987. Since then, the number of horizontal wells drilled has escalated rapidly, averaging approximately 500 per year since 1993. When combined with horizontal wells drilled in Alberta, the major Canadian oil-producing province, the total number drilled in 1995 was 978. This total exceeds the National Energy Board (NEB) projected maximum of 816 wells per year. The NEB projections were based on a break-even point for the drilling of horizontal wells of a return of CDN $285,000 using a discount rate of 15%. This corresponded to a cumulative production from each individual well of some 11,000 m3. The introduction of a royalty-free production volume of 12,000 m3 per horizontal well in Saskatchewan was instrumental in stimulating the rapid expansion in the use of horizontal wells and helping Canada to exceed the forecasted drilling level. Within Saskatchewan, daily production from 1964 active horizontal wells is in excess of 20,000 m3. Comparative analysis indicates that the average daily production per well has increased from approximately by 40% with the advent of horizontal wells. In total production terms, provincial production has increased from 11.7 million cubic metres in 1989 to 20.9 million m3 in 1996. This represents an increase of almost 79% based primarily on the extensive use of horizontal wells. In 1996, horizontal wells produced 36% of the province's oil from 12% of the active wells. In the southeastern producing areas of Saskatchewan, the Williston Basin, declining oil-production has jumped 100%, with horizontal wells accounting for approximately 50% of total regional production. Pay zones in this areas, as in most of the province, tend to be relatively thin, with net pay frequently less that 5 m. The modest investment of some CDN $5 million in government research funding 10 years ago to stimulate the development of horizontal wells, combined with a favourable royalty structure, has been at least

  20. Stochastic Transition between Turbulent Branch and Thermodynamic Branch of an Inhomogeneous Plasma

    OpenAIRE

    Kawasaki, Mitsuhiro; Itoh, Sanae-I.; Yagi, Masatoshi; Itoh, Kimitaka

    2002-01-01

    Transition phenomena between thermodynamic branch and turbulent branch in submarginal turbulent plasma are analyzed with statistical theory. Time-development of turbulent fluctuation is obtained by numerical simulations of Langevin equation which contains submarginal characteristics. Probability density functions and transition rates between two states are analyzed. Transition from turbulent branch to thermodynamic branch occurs in almost entire region between subcritical bifurcation point an...

  1. Intra-firm Horizontal Knowledge Transfer Management

    Institute of Scientific and Technical Information of China (English)

    WANG Yaowu; WANG Yanhang

    2009-01-01

    Knowledge transfer is widely emphasized as a strategic issue for firm competition. A model for intra-firm horizontal knowledge transfer is proposed to model horizontal knowledge transfer to solve some demerits in current knowledge transfer researches. The concept model of intra-firm horizontal knowledge transfer was described and a framework was provided to define the main components of thetransfer process. Horizontal knowledge transfer is that knowledge is transferred from the source to the same hierarchical level recipients as the target. Horizontal knowledge transfer constitutes a strategic area of knowledge management research. However, little is known about the circumstances under which one particular mechanism is the most appropriate. To address these issues, some significant conclusions are drawn concerning knowledge transfer mechanisms in a real-world setting.

  2. Importance of anatomically locating the infrapatellar branch of the saphenous nerve in reconstructing the anterior cruciate ligament using flexor tendons,

    Directory of Open Access Journals (Sweden)

    Julio Cesar Gali

    2014-12-01

    Full Text Available Objective:To describe the path of the infrapatellar branch of the saphenous nerve (IBSN using the medial joint line, anterior tibial tuberosity (ATT, tibial collateral ligament and a horizontal line parallel to the medial joint line that passes over the ATT, as reference points, in order to help surgeons to diminish the likelihood of injuring this nerve branch during reconstruction of the anterior cruciate ligament (ACL using flexor tendons.Methods:Ten frozen knees that originated from amputations were examined. Through anatomical dissection performed with the specimens flexed, we sought to find the IBSN, from its most medial and proximal portion to its most lateral and distal portion. Following this, the anatomical specimens were photographed and, using the ImageJ software, we determined the distance from the IBSN to the medial joint line and to a lower horizontal line going through the ATT and parallel to the first line. We also measured the angle of the direction of the path of the nerve branch in relation to this lower line.Results:The mean angle of the path of the nerve branch in relation to the lower horizontal line was 17.50 ±6.17°. The mean distance from the IBSN to the medial joint line was 2.61 ± 0.59 cm and from the IBSN to the lower horizontal line, 1.44 ±0.51 cm.Conclusion:The IBSN was found in all the knees studied. In three knees, we found a second branch proximal to the first one. The direction of its path was always from proximal and medial to distal and lateral. The IBSN was always proximal and medial to the ATT and distal to the medial joint line. The medial angle between its direction and a horizontal line going through the ATT was 17.50 ± 6.17°.

  3. PERSONALISED DENTURES WITH BRANCHING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Puneet

    2012-12-01

    Full Text Available ABSTRACT: While the basic process of making dentures has chang ed little over the past several decades, new materials and techniques can help labor atories and clinicians provide functional, esthetic restorations that offer exceptional value t o patients. Unlike the conventional “linear” methods which foll ow specific steps in a cookbook fashion, the Branching Technique is a dynamic conce pt which can be adjusted to meet the clinical needs of each patient. This customized tec hnique allows for a “trial” denture to be worn by each patient that is used to pinpoint and solve th e patient’s denture problems before the final denture is made. This individualized approach helps t o eliminate disappointments or surprises. From the preliminary impressions and the “training” d enture (it’s actually a provisional denture to the functional impressions and porcelain teeth to hold the patient’s vertical dimension, the Branching Technique produces the most esthetically pleasing and functionally stable dentures possible.

  4. Effects of Traditional Versus Horizontal Inertial Flywheel Power Training on Common Sport-Related Tasks

    OpenAIRE

    de Hoyo Moisés; Sañudo Borja; Carrasco Luis; Domínguez-Cobo Sergio; Mateo-Cortes Jesús; Cadenas-Sánchez María Monserrat; Nimphius Sophia

    2015-01-01

    This study aimed to analyze the effects of power training using traditional vertical resistance exercises versus direction specific horizontal inertial flywheel training on performance in common sport-related tasks. Twenty-three healthy and physically active males (age: 22.29 ± 2.45 years) volunteered to participate in this study. Participants were allocated into either the traditional training (TT) group where the half squat exercise on a smith machine was applied or the horizontal flywheel ...

  5. Developing Engineering-oriented Educational Workshops Within a Student Branch

    OpenAIRE

    Verveckken, Jan; Geth, Frederik; Hunyadi, Borbála; Beerten, Jef; Leemput, Niels; Roy, Juan Van; Tielens, Pieter; De Smedt, Valentijn; Iacovella, Sandro; Koolen, Ninah; De Clercq, Hans; Driesen, Johan; Gielen, Georges; Puers, Bob; Vandewalle, Joos

    2013-01-01

    The development of two educational workshops, one on energy efficiency and one on human-machine interfaces, is detailed and discussed. Attraction to engineering is not created as much as lost at early ages through current education methods. Through positive, hands-on experiences with engineering in K-12 education, this trend can be turned. IEEE student branches have as part of their mission the education and creation of quality educational resources for the public. After searching in vain for...

  6. An aberrant right lateral branch from right internal thoracic artery

    OpenAIRE

    Salve VM; Ratnaprabha C

    2010-01-01

    The internal thoracic artery is the largest artery of the thoracic wall. The internal thoracic artery is often mobilized for coronary artery bypass grafting. During routine dissection (MBBS Batch 2009-2010) of a middle aged male cadaver at Dr. Pinnamaneni Siddhartha Institute of Medical Sciences & Research Foundation, Gannavaram, (INDIA); an aberrant right lateral branch from right internal thoracic artery was found. It arose from right internal thoracic artery behind right first rib. It ran ...

  7. Optimizing of Culture Conditionin Horizontal Rotating Bioreactor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionBioreactor is the most important equipment in tissue engineering. It can mimic the micro-environment of cell growth in vitro. At present, horizontal rotating bioreactor is the most advanced equipment for cell culture in the world. 2 Rotating bioreactors2.1 Working principleThere are two kinds of horizontal rotating bioreactor: HARV(high aspect ratio vessel) and RCCS (rotary cell culture system). It is drived by step motor with horizontal rotation, the culture medium and cell is filled between ...

  8. Horizontal gene transfer and bacterial diversity

    Indian Academy of Sciences (India)

    Chitra Dutta; Archana Pan

    2002-02-01

    Bacterial genomes are extremely dynamic and mosaic in nature. A substantial amount of genetic information is inserted into or deleted from such genomes through the process of horizontal transfer. Through the introduction of novel physiological traits from distantly related organisms, horizontal gene transfer often causes drastic changes in the ecological and pathogenic character of bacterial species and thereby promotes microbial diversification and speciation. This review discusses how the recent influx of complete chromosomal sequences of various microorganisms has allowed for a quantitative assessment of the scope, rate and impact of horizontally transmitted information on microbial evolution.

  9. Branching diffusions in random environment

    CERN Document Server

    Böinghoff, Christian

    2011-01-01

    We consider the diffusion approximation of branching processes in random environment (BPREs). This diffusion approximation is similar to and mathematically more tractable than BPREs. We obtain the exact asymptotic behavior of the survival probability. As in the case of BPREs, there is a phase transition in the subcritical regime due to different survival opportunities. In addition, we characterize the process conditioned to never go extinct and establish a backbone construction. In the strongly subcritical regime, mean offspring numbers are increased but still subcritical in the process conditioned to never go extinct. Here survival is solely due to an immortal individual, whose offspring are the ancestors of additional families. In the weakly subcritical regime, the mean offspring number is supercritical in the process conditioned to never go extinct. Thus this process survives with positive probability even if there was no immortal individual.

  10. Recursive Branching Simulated Annealing Algorithm

    Science.gov (United States)

    Bolcar, Matthew; Smith, J. Scott; Aronstein, David

    2012-01-01

    This innovation is a variation of a simulated-annealing optimization algorithm that uses a recursive-branching structure to parallelize the search of a parameter space for the globally optimal solution to an objective. The algorithm has been demonstrated to be more effective at searching a parameter space than traditional simulated-annealing methods for a particular problem of interest, and it can readily be applied to a wide variety of optimization problems, including those with a parameter space having both discrete-value parameters (combinatorial) and continuous-variable parameters. It can take the place of a conventional simulated- annealing, Monte-Carlo, or random- walk algorithm. In a conventional simulated-annealing (SA) algorithm, a starting configuration is randomly selected within the parameter space. The algorithm randomly selects another configuration from the parameter space and evaluates the objective function for that configuration. If the objective function value is better than the previous value, the new configuration is adopted as the new point of interest in the parameter space. If the objective function value is worse than the previous value, the new configuration may be adopted, with a probability determined by a temperature parameter, used in analogy to annealing in metals. As the optimization continues, the region of the parameter space from which new configurations can be selected shrinks, and in conjunction with lowering the annealing temperature (and thus lowering the probability for adopting configurations in parameter space with worse objective functions), the algorithm can converge on the globally optimal configuration. The Recursive Branching Simulated Annealing (RBSA) algorithm shares some features with the SA algorithm, notably including the basic principles that a starting configuration is randomly selected from within the parameter space, the algorithm tests other configurations with the goal of finding the globally optimal

  11. Branching process models of cancer

    CERN Document Server

    Durrett, Richard

    2015-01-01

    This volume develops results on continuous time branching processes and applies them to study rate of tumor growth, extending classic work on the Luria-Delbruck distribution. As a consequence, the authors calculate the probability that mutations that confer resistance to treatment are present at detection and quantify the extent of tumor heterogeneity. As applications, the authors evaluate ovarian cancer screening strategies and give rigorous proofs for results of Heano and Michor concerning tumor metastasis. These notes should be accessible to students who are familiar with Poisson processes and continuous time. Richard Durrett is mathematics professor at Duke University, USA. He is the author of 8 books, over 200 journal articles, and has supervised more than 40 Ph.D. students. Most of his current research concerns the applications of probability to biology: ecology, genetics, and most recently cancer.

  12. The age structure of the Milky Way's halo

    CERN Document Server

    Carollo, Daniela; Placco, Vinicius; Santucci, Rafael; Denissenkov, Pavel; Tissera, Patricia; Lentner, Geoffrey; Rossi, Silvia; Lee, Young Sun; Tumlinson, Jason

    2016-01-01

    We present a new, high-resolution chronographic (age) map of the Milky Way's halo, based on the inferred ages of ~130,000 field blue horizontal-branch (BHB) stars with photometry from the Sloan Digital Sky Survey. Our map exhibits a strong central concentration of BHB stars with ages greater than 12 Gyr, extending up to ~15 kpc from the Galactic center (reaching close to the solar vicinity), and a decrease in the mean ages of field stars with distance by 1-1.5 Gyr out to ~45-50 kpc, along with an apparent increase of the dispersion of stellar ages, and numerous known (and previously unknown) resolved over-densities and debris streams, including the Sagittarius Stream. These results agree with expectations from modern LambdaCDM cosmological simulations, and support the existence of a dual (inner/outer) halo system, punctuated by the presence of over-densities and debris streams that have not yet completely phase-space mixed.

  13. Vegetation survey of PEN Branch wetlands

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    A survey was conducted of vegetation along Pen Branch Creek at Savannah River Site (SRS) in support of K-Reactor restart. Plants were identified to species by overstory, understory, shrub, and groundcover strata. Abundance was also characterized and richness and diversity calculated. Based on woody species basal area, the Pen Branch delta was the most impacted, followed by the sections between the reactor and the delta. Species richness for shrub and groundcover strata were also lowest in the delta. No endangered plant species were found. Three upland pine areas were also sampled. In support of K Reactor restart, this report summarizes a study of the wetland vegetation along Pen Branch. Reactor effluent enters Indian Grove Branch and then flows into Pen Branch and the Pen Branch Delta.

  14. High hydraulic performance in horizontal waterwheels

    Energy Technology Data Exchange (ETDEWEB)

    Pujol, T.; Montoro, L. [Area de Mecnica de Fluids, Escola Politcnica Superior, Universitat de Girona, 17071 Girona, Catalonia (Spain)

    2010-11-15

    Slow rotating waterwheels have been recently proposed as affordable sources of renewable energy in rural areas. In terms of hydraulic efficiency, classical horizontal waterwheels reach values on the order of 50%, being well below those obtained from overshot (71%), waterfall (66%) and, even, undershot (65%) vertical ones. Based on the study of an horizontal waterwheel built prior to 1940s that includes features from both elementary turbines and antique waterwheels, we conclude that horizontal waterwheels may actually reach hydraulic efficiencies as high as 81%. These quantitative results are obtained by analytical approximations and, more important, by numerical integrations through accurate computational fluid dynamics (CFD) simulations. In addition, we show that such a high hydraulic efficiency does not substantially vary when changing the net available head. We suggest that this relevant progress made on improving the efficiency of classical horizontal waterwheels may have implications in future designs of nano/micro hydropower devices. (author)

  15. 3D modelling of branching in plants

    OpenAIRE

    Evers, J.B.

    2011-01-01

    Shoot branching is a key determinant of overall aboveground plant form. During plant development, the number of branches formed strongly influences the amount of light absorbed by the plant, and thus the plant’s competitive strength in terms of light capture in relation to neighbouring plants. Branching is regulated by multiple internal factors which are modulated by different environmental signals. A key environmental signal in the context of a plant population is a low red / far-red intensi...

  16. Horizontal Evaluation: Stimulating social learning among peers

    OpenAIRE

    Thiele, Graham; Devaux, Andre; Velasco, Claudio; Manrique, Kurt

    2006-01-01

    Horizontal evaluation is a flexible evaluation method that combines self-assessment and external review by peers. We have developed and applied this method for use within an Andean regional network that develops new methodologies for research and development (R&D). The involvement of peers neutralizes the lopsided power relations that prevail in traditional external evaluations, creating a more favourable atmosphere for learning and improvement. The central element of a horizontal evaluation ...

  17. HORIZONTAL WELL DRILL-IN FLUIDS

    OpenAIRE

    Nediljka Gaurina-Međimurec

    1998-01-01

    Main objective of horizontal driling is to place a drain-hole for a long distance within the pay zone to enhance productivity or injectivity. In drilling horizontal wells, more serious problems appear than in drilling vertical wells. These problems are: poor hole cleaning, excessive torque and drag, hole filling, pipe stucking, wellbore instability, loss of circulation, formation damage, poor cement job, and difficulties at logging jobs. From that reason, successful drilling and production of...

  18. In Situ Remediation using Horizontal Wells

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Horizontal well technology has been widely used in petroleum and underground utility installation. Since late 1980's, the technology has been adapted for environmental remediation applications. Two general methods in drilling horizontal wells have been used in remediation, trenched and directionally-drilled. The first method involves the excavation of a relatively large diameter borehole, with simultaneous installation of well materials and backfill. The second method, directional drilling, p...

  19. CORRECTED CALCULATION OF HORIZONTAL GATING SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. A. Zayatz

    2015-05-01

    Full Text Available In the course of fulfillment of work the specified calculations of horizontal gating systems for various parts produced in dispensable molds were carried out. The results of work showed that the weight removal value in gating systems fluctuates in big intervals and the specified calculation of horizontal gating systems enables to calculate precisely their weight that allows to calculate quantity of metal in metal charge.

  20. Horizontal Brand Extension and Customer perception

    OpenAIRE

    Khan, Khalid; Janthimapornkij, Rattanawilai

    2011-01-01

    Company use different method for extended their business to different market and to different segment. They use different method; brand extension is one of popular strategy for extension of business. Brand extension does not become successful for every brand, it is very risky. The purpose of this thesis is to study horizontal brand extension and customer perception. We will discuss horizontal brand extension and its two main types franchise brand extension and line extension. Brand extension ...

  1. Emotion recognition (sometimes) depends on horizontal orientations

    OpenAIRE

    Huynh, Carol M; Balas, Benjamin

    2014-01-01

    Face recognition depends critically on horizontal orientations (Goffaux & Dakin, 2010). Face images that lack horizontal features are harder to recognize than those that have that information preserved. Presently, we asked if facial emotional recognition also exhibits this dependency by asking observers to categorize orientation-filtered happy and sad expressions. Furthermore, we aimed to dissociate image-based orientation energy from object-based orientation by rotating images 90-degrees in ...

  2. Branched silver nanowires as controllable plasmon routers.

    Science.gov (United States)

    Fang, Yurui; Li, Zhipeng; Huang, Yingzhou; Zhang, Shunping; Nordlander, Peter; Halas, Naomi J; Xu, Hongxing

    2010-05-12

    Using polarization dependent scattering spectroscopy, we investigate plasmon propagation on branched silver nanowires. By controlling the polarization of the incident laser light, the wire plasmons can be routed into different wire branches and result in light emission from the corresponding wire ends. This routing behavior is found to be strongly dependent on the wavelength of light. Thus for certain incident polarizations, light of different wavelength will be routed into different branches. The branched nanowire can thus serve as a controllable router and multiplexer in integrated plasmonic circuits. PMID:20420411

  3. Emotion recognition (sometimes) depends on horizontal orientations.

    Science.gov (United States)

    Huynh, Carol M; Balas, Benjamin

    2014-07-01

    Face recognition depends critically on horizontal orientations (Goffaux & Dakin, Frontiers in Psychology, 1(143), 1-14, 2010): Face images that lack horizontal features are harder to recognize than those that have this information preserved. We asked whether facial emotional recognition also exhibits this dependency by asking observers to categorize orientation-filtered happy and sad expressions. Furthermore, we aimed to dissociate image-based orientation energy from object-based orientation by rotating images 90 deg in the picture plane. In our first experiment, we showed that the perception of emotional expression does depend on horizontal orientations, and that object-based orientation constrained performance more than image-based orientation did. In Experiment 2, we showed that mouth openness (i.e., open vs. closed mouths) also influenced the emotion-dependent reliance on horizontal information. Finally, we describe a simple computational analysis that demonstrates that the impact of mouth openness was not predicted by variation in the distribution of orientation energy across horizontal and vertical orientation bands. Overall, our results suggest that emotion recognition largely does depend on horizontal information defined relative to the face, but that this bias is modulated by multiple factors that introduce variation in appearance across and within distinct emotions. PMID:24664854

  4. Branch mode selection during early lung development.

    Directory of Open Access Journals (Sweden)

    Denis Menshykau

    Full Text Available Many organs of higher organisms, such as the vascular system, lung, kidney, pancreas, liver and glands, are heavily branched structures. The branching process during lung development has been studied in great detail and is remarkably stereotyped. The branched tree is generated by the sequential, non-random use of three geometrically simple modes of branching (domain branching, planar and orthogonal bifurcation. While many regulatory components and local interactions have been defined an integrated understanding of the regulatory network that controls the branching process is lacking. We have developed a deterministic, spatio-temporal differential-equation based model of the core signaling network that governs lung branching morphogenesis. The model focuses on the two key signaling factors that have been identified in experiments, fibroblast growth factor (FGF10 and sonic hedgehog (SHH as well as the SHH receptor patched (Ptc. We show that the reported biochemical interactions give rise to a Schnakenberg-type Turing patterning mechanisms that allows us to reproduce experimental observations in wildtype and mutant mice. The kinetic parameters as well as the domain shape are based on experimental data where available. The developed model is robust to small absolute and large relative changes in the parameter values. At the same time there is a strong regulatory potential in that the switching between branching modes can be achieved by targeted changes in the parameter values. We note that the sequence of different branching events may also be the result of different growth speeds: fast growth triggers lateral branching while slow growth favours bifurcations in our model. We conclude that the FGF10-SHH-Ptc1 module is sufficient to generate pattern that correspond to the observed branching modes.

  5. Branch mode selection during early lung development.

    Science.gov (United States)

    Menshykau, Denis; Kraemer, Conradin; Iber, Dagmar

    2012-01-01

    Many organs of higher organisms, such as the vascular system, lung, kidney, pancreas, liver and glands, are heavily branched structures. The branching process during lung development has been studied in great detail and is remarkably stereotyped. The branched tree is generated by the sequential, non-random use of three geometrically simple modes of branching (domain branching, planar and orthogonal bifurcation). While many regulatory components and local interactions have been defined an integrated understanding of the regulatory network that controls the branching process is lacking. We have developed a deterministic, spatio-temporal differential-equation based model of the core signaling network that governs lung branching morphogenesis. The model focuses on the two key signaling factors that have been identified in experiments, fibroblast growth factor (FGF10) and sonic hedgehog (SHH) as well as the SHH receptor patched (Ptc). We show that the reported biochemical interactions give rise to a Schnakenberg-type Turing patterning mechanisms that allows us to reproduce experimental observations in wildtype and mutant mice. The kinetic parameters as well as the domain shape are based on experimental data where available. The developed model is robust to small absolute and large relative changes in the parameter values. At the same time there is a strong regulatory potential in that the switching between branching modes can be achieved by targeted changes in the parameter values. We note that the sequence of different branching events may also be the result of different growth speeds: fast growth triggers lateral branching while slow growth favours bifurcations in our model. We conclude that the FGF10-SHH-Ptc1 module is sufficient to generate pattern that correspond to the observed branching modes. PMID:22359491

  6. The branch banking boom in Illinois: a byproduct of restrictive branching laws

    OpenAIRE

    Erin Davis; Tara Rice

    2007-01-01

    What’s behind the boom in bank branches across Illinois, particularly in Chicago? The authors explore the history of branch banking within the state and across the nation to help explain this recent trend and discuss its future implications.

  7. 孕期酒精暴露对子鼠视网膜双极细胞和水平细胞发育的影响%Prenatal alcohol exposure affects development of retinal bipolar and horizontal cells in mice

    Institute of Scientific and Technical Information of China (English)

    刘曦; 王永毅; 姚焕玲; 赵博; 于亚东; 胡馨; 邓锦波

    2012-01-01

    Objective To investigate effects of alcohol exposure during pregnancy on retinal bipolar and horizontal cells in filial mice. Methods The animal model of prenatal alcohol exposure was made. The development of bipolar cells and horizontal cells at prenatal days 7, 14 and 30 was investigated with immunofluorescent labeling and Dil scattering techniques. Results In all age groups, the density of the bipolar cells was significantly lower in the experiment groups than in the control groups. The dendritic field and the number of branches of horizontal cells were significantly lower in the experimental group than in the control group (P < 0. 01). Conclusion Alcohol exposure during pregnancy affects development of retinal bipolar and horizontal cells in mice.%目的 探讨孕期酒精暴露对子鼠视网膜双极细胞和水平细胞发育的影响.方法 建立孕期酒精暴露小鼠模型;采用免疫荧光染色和DiI散射技术,观察酒精对日龄7d(P7)、P14和P30子鼠视网膜双极细胞和水平细胞的影响.结果 各年龄组中,酒精组视网膜双极细胞的密度明显低于对照组,且呈剂量依赖性和长时程效应;水平细胞的树突野及树突数也明显低于对照组,呈剂量依赖性和长时程效应(P<0.01).结论 孕期酒精暴露影响子鼠视网膜双极细胞和水平细胞的发育.

  8. Branched-Chain Amino Acids

    Directory of Open Access Journals (Sweden)

    Matteo Ghiringhelli

    2015-07-01

    Full Text Available Our study is focused on evaluation and use of the most effective and correct nutrients. In particular, our attention is directed to the role of certain amino acids in cachectic patients.During parenteral nutrition in humans, physician already associates in the PN-bags different formulations including amino acids, lipids and glucose solutions or essential amino acids solution alone or exclusively branched-chain amino acids (BCAA. Studies investigated the effects of dietary BCAA ingestion on different diseases and conditions such as obesity and metabolic disorders, liver disease, muscle atrophy, cancer, impaired immunity or injuries (surgery, trauma, burns, and sepsis. BCAAs have been shown to affect gene expression, protein metabolism, apoptosis and regeneration of hepatocytes, and insulin resistance. They have also been shown to inhibit the proliferation of liver cancer cells in vitro, and are essential for lymphocyte proliferation and dendritic cell maturation. Oral or parenteral administration of these three amino acids will allow us to evaluate the real efficacy of these compounds during a therapy to treat malnutrition in subjects unable to feed themselves.

  9. AVM branch vibration test equipment

    International Nuclear Information System (INIS)

    An inventory of the test equipment of the AVM Branch ''Acoustic and Vibratory Mechanics Analysis Methods'' group has been undertaken. The purpose of this inventory is to enable better acquaintance with the technical characteristics of the equipment, providing an accurate definition of their functionalities, ad to inform potential users of the possibilities and equipment available in this field. The report first summarizes the various experimental surveys conduced. Then, using the AVM equipment database to draw up an exhaustive list of available equipment, it provides a full-scope picture of the vibration measurement systems (sensors, conditioners and exciters) and data processing resources commonly used on industrial sites and in laboratories. A definition is also given of a mobile test unit, called 'shelter', and a test bench used for the testing and performance rating of the experimental analysis methods developed by the group. The report concludes with a description of two fixed installations: - the calibration bench ensuring the requisite quality level for the vibration measurement systems ; - the training bench, whereby know-how acquired in the field in the field of measurement and experimental analysis processes is made available to others. (author). 27 refs., 15 figs., 2 appends

  10. The power of phylogenetic approaches to detect horizontally transferred genes

    Directory of Open Access Journals (Sweden)

    Gogarten J Peter

    2007-03-01

    Full Text Available Abstract Background Horizontal gene transfer plays an important role in evolution because it sometimes allows recipient lineages to adapt to new ecological niches. High genes transfer frequencies were inferred for prokaryotic and early eukaryotic evolution. Does horizontal gene transfer also impact phylogenetic reconstruction of the evolutionary history of genomes and organisms? The answer to this question depends at least in part on the actual gene transfer frequencies and on the ability to weed out transferred genes from further analyses. Are the detected transfers mainly false positives, or are they the tip of an iceberg of many transfer events most of which go undetected by current methods? Results Phylogenetic detection methods appear to be the method of choice to infer gene transfers, especially for ancient transfers and those followed by orthologous replacement. Here we explore how well some of these methods perform using in silico transfers between the terminal branches of a gamma proteobacterial, genome based phylogeny. For the experiments performed here on average the AU test at a 5% significance level detects 90.3% of the transfers and 91% of the exchanges as significant. Using the Robinson-Foulds distance only 57.7% of the exchanges and 60% of the donations were identified as significant. Analyses using bipartition spectra appeared most successful in our test case. The power of detection was on average 97% using a 70% cut-off and 94.2% with 90% cut-off for identifying conflicting bipartitions, while the rate of false positives was below 4.2% and 2.1% for the two cut-offs, respectively. For all methods the detection rates improved when more intervening branches separated donor and recipient. Conclusion Rates of detected transfers should not be mistaken for the actual transfer rates; most analyses of gene transfers remain anecdotal. The method and significance level to identify potential gene transfer events represent a trade

  11. Branching out Has So Much to Offer

    Science.gov (United States)

    Murray, Joe

    2012-01-01

    In 1989 there were thirty ATM branches nationally. In January 2012 there were just twelve ATM branches with another three "proposed". How can that happen? How did it happen? Maybe the most pertinent question is: Why did it happen? There is no single answer to the last question, but perhaps it was something to do with the changes that were sweeping…

  12. 12 CFR 741.11 - Foreign branching.

    Science.gov (United States)

    2010-01-01

    ...) Contents of Business Plan. The written business plan must address the following: (1) Analysis of market... regarding the branch (shares, lending, capital, charge-offs, collections); (6) The field of membership or... for branch operations (balance sheet and income and expense projections) for the first and second...

  13. Spectral problem for branching chain quantum graph

    International Nuclear Information System (INIS)

    Branching chain of rings as a quantum graph is considered. We use the transfer matrix method to obtain the spectral equation. The existence of bound states is proved. The discrete spectrum of the Schrödinger operator for the system is described. We find the dependence of the eigenvalues positions on the branching angle.

  14. Horizontal alveolar bone loss: A periodontal orphan

    Directory of Open Access Journals (Sweden)

    Jayakumar A

    2010-01-01

    Full Text Available Background: Attempts to successfully regenerate lost alveolar bone have always been a clinician′s dream. Angular defects, at least, have a fairer chance, but the same cannot be said about horizontal bone loss. The purpose of the present study was to evaluate the prevalence of horizontal alveolar bone loss and vertical bone defects in periodontal patients; and later, to correlate it with the treatment modalities available in the literature for horizontal and vertical bone defects. Materials and Methods: The study was conducted in two parts. Part I was the radiographic evaluation of 150 orthopantomographs (OPGs (of patients diagnosed with chronic periodontitis and seeking periodontal care, which were digitized and read using the AutoCAD 2006 software. All the periodontitis-affected teeth were categorized as teeth with vertical defects (if the defect angle was ≤45° and defect depth was ≥3 mm or as having horizontal bone loss. Part II of the study comprised search of the literature on treatment modalities for horizontal and vertical bone loss in four selected periodontal journals. Results: Out of the 150 OPGs studied, 54 (36% OPGs showed one or more vertical defects. Totally, 3,371 teeth were studied, out of which horizontal bone loss was found in 3,107 (92.2% teeth, and vertical defects were found only in 264 (7.8% of the teeth, which was statistically significant (P<.001. Search of the selected journals revealed 477 papers have addressed the treatment modalities for vertical and horizontal types of bone loss specifically. Out of the 477 papers, 461 (96.3% have addressed vertical bone loss, and 18 (3.7% have addressed treatment options for horizontal bone loss. Two papers have addressed both types of bone loss and are included in both categories. Conclusion: Horizontal bone loss is more prevalent than vertical bone loss but has been sidelined by researchers as very few papers have been published on the subject of regenerative treatment

  15. IDENTIFYING PATTERNS OF FACIAL NERVE BRANCHES WITH REVIEW OF LITERATURE

    Directory of Open Access Journals (Sweden)

    Shakuntala Rao

    2014-04-01

    Full Text Available The facial nerve is highly variable and complex in its extra cranial course. Past studies have described patterns of branching in the face and anastomoses between branches. The studies have also thrown light on the significance of the patterns for the surgeon. With more and more development of surgical and aesthetic procedures evolving, an attempt has been made to identify all previously described named patterns with review of past literature and recognize any newer patterns to be noted and recorded. Adult human cadavers (24 which were allotted to first year medical students in the department of Anatomy, P.E.S Medical College, for routine dissection as per schedule were used for the study. One full term fetus was also included in the study. Dissection was done on either side of the faces and therefore the total sample size was considered to be 50 cervicofacial halves. The age of the cadavers was unknown at the time of dissection. The conventional method of dissection was used to identify and trace the facial nerve and its branches. The variability of branching pattern of facial nerve was observed. The patterns observed in this study were compared to patterns described by Davis et al in 1956.Twelve specimens(24/48 cervicofacial halves, showed straight branching pattern(type-1.Three specimens(6/48, cervico-facial halves showed anastomosis in temporo-facial division(type-II, Three (6/48, specimens showed loop formation between divisions(type-III. The type-VI which is a complex pattern of intricate anastomosis of all the branches was seen in four specimens (8/48.In two (4/48 specimens there was loop formation in the cervicofacial division. A larger cervicofacial division was seen in one of the specimens (2/48.The fetal halves did not show any anastomosis between the branches. An attempt has been made to identify the different patterns described with review of literature, to find out any new patterns and to correlate surgical significance of the

  16. Analysis of vocal and swallowing functions after horizontal glottectomy.

    Science.gov (United States)

    Topaloğlu, İlhan; Bal, Muhlis; Salturk, Ziya; Berkiten, Güler; Atar, Yavuz

    2016-08-01

    We conducted a cross-sectional study to assess vocal and swallowing functions after horizontal glottectomy. Our study population was made up of 22 men aged 45 to 72 years (mean: 58.3) who underwent horizontal glottectomy and completed at least 1 year of follow-up. To compare postoperative results, 20 similarly aged men were included as a control group; all glottectomy patients and all controls were smokers. We used three methods-acoustic and aerodynamic voice analyses, the GRBAS (grade, roughness, breathiness, asthenicity, and strain) scale, and the voice handicap index-30 (VHI-30)-to assess vocal function objectively, perceptually, and subjectively, respectively. We also assessed swallowing function objectively by fiberoptic endoscopic evaluation of swallowing (FEES) and subjectively with the M.D. Anderson dysphagia inventory (MDADI). The 22 patients were also subcategorized into three groups according to the extent of their arytenoid cartilage resection, and their outcomes were compared. Acoustic and aerodynamic analyses showed that the mean maximum phonation time was significantly shorter and the fundamental frequency was significantly lower in the glottectomy group than in the controls (p = 0.001 for both), and that the mean jitter and shimmer values and the mean harmonics-to-noise ratio were all significantly higher (p = 0.001 for all); there were no significant differences among the three arytenoid subgroups. Self-assessments revealed that there were no statistically significant differences among the three subgroups in GRBAS scale scores except for the breathiness score (p = 0.045), which was lower in the arytenoid preservation subgroup than in the total resection subgroup; there were no statistically significant differences among the three subgroups in VHI-30 scores. Finally, swallow testing found no statistically significant differences in FEES scores or MDADI scores. We conclude that horizontal glottectomy caused a deterioration in vocal function, but

  17. Accounting for horizontal gene transfers explains conflicting hypotheses regarding the position of aquificales in the phylogeny of Bacteria

    OpenAIRE

    Gouy Manolo; Guéguen Laurent; Boussau Bastien

    2008-01-01

    Abstract Background Despite a large agreement between ribosomal RNA and concatenated protein phylogenies, the phylogenetic tree of the bacterial domain remains uncertain in its deepest nodes. For instance, the position of the hyperthermophilic Aquificales is debated, as their commonly observed position close to Thermotogales may proceed from horizontal gene transfers, long branch attraction or compositional biases, and may not represent vertical descent. Indeed, another view, based on the ana...

  18. HORIZONTAL WELL DRILL-IN FLUIDS

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1998-12-01

    Full Text Available Main objective of horizontal driling is to place a drain-hole for a long distance within the pay zone to enhance productivity or injectivity. In drilling horizontal wells, more serious problems appear than in drilling vertical wells. These problems are: poor hole cleaning, excessive torque and drag, hole filling, pipe stucking, wellbore instability, loss of circulation, formation damage, poor cement job, and difficulties at logging jobs. From that reason, successful drilling and production of horizontal well depends largely on the fluid used during drilling and completion phases. Several new fluids, that fulfill some or all of required properties (hole cleaning, cutting suspension, good lubrication, and relative low formation damage, are presented in this paper.

  19. Horizontal stirring in the global ocean

    CERN Document Server

    Hernández-Carrasco, I; Hernández-García, E; Turiel, A

    2011-01-01

    Horizontal mixing and the distribution of coherent structures in the global ocean are analyzed using Finite-Size Lyapunov Exponents (FSLE), computed for the surface velocity field derived from the Ocean general circulation model For the Earth Simulator (OFES). FSLEs measure horizontal stirring and dispersion; additionally, the transport barriers which organize the oceanic flow can roughly be identified with the ridges of the FSLE field. We have performed a detailed statistical study, particularizing for the behaviour of the two hemispheres and different ocean basins. The computed Probability Distributions Functions (PDFs) of FSLE are broad and asymmetric. Horizontal mixing is generally more active in the northern hemisphere than in the southern one. Nevertheless the Southern Ocean is the most active ocean, and the Pacific the less active one. A striking result is that the main currents can be classified in two 'activity classes': Western Boundary Currents, which have broad PDFs with large FSLE values, and Eas...

  20. Diffuser Augmented Horizontal Axis Tidal Current Turbines

    Directory of Open Access Journals (Sweden)

    Nasir Mehmood

    2012-09-01

    Full Text Available The renewal energy technologies are increasingly popular to ensure future energy sustenance and address environmental issues. The tides are enormous and consistent untapped resource of renewable energy. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The tidal energy industry is undergoing an increasing shift towards diffuser augmented turbines. The reason is the higher power output of diffuser augmented turbines compared to conventional open turbines. The purpose of this study is to present a comprehensive review of diffuser augmented horizontal axis tidal current turbines. The components, relative advantages, limitations and design parameters of diffuser augmented horizontal axis tidal current turbines are presented in detail. CFD simulation of NACA 0016 airfoil is carried out to explore its potential for designing a diffuser. The core issues associated with diffuser augmented horizontal axis tidal current turbines are also discussed.

  1. Holographic Charge Excitations on Horizontal Boundary

    CERN Document Server

    Hotta, M

    2002-01-01

    We argue that states with nontrivial horizontal charges of BTZ black hole can be excited by ordinary falling matter including Hawking radiation. The matter effect does not break the integrability condition of the charges on the horizon. Thus we are able to trace the proccesses in which the matter imprints the information on the horizon by use of the charged states. It is naturally expected that in the thermal equilibrium with the Hawking radiation the black hole wanders ergodically through different horizontal states due to thermal fluctuation of incoming matter. This fact strengthens plausibility of the basic part of Carlip's idea. We also discuss some aspects of the quantum horizontal symmetry and conjecture how the precise black hole entropy will be given from our point of view.

  2. [Croatian Medical Association--Branch Zagreb].

    Science.gov (United States)

    Kaić, Zvonimir; Sain, Snjezana; Gulić, Mirjana; Mahovlić, Vjekoslav; Krznarić, Zeljko

    2014-01-01

    The available literature shows us that "Druztvo ljeciteljah u Zagrebus (the Society of Healers in Zagreb) was founded as far back as the year 1845 by a total of thirteen members. This data allows us to follow the role of doctors and health workers in Zagreb through their everyday profession, research, organizational and social work as well as management through a period of over one hundred to seventy years. The Branch Zagreb was active before the official establishment of subsidiaries of CMA which is evident from the minutes of the regular annual assembly of the Croatian Medical Association on 21 March 1948. Until the end of 1956, there was no clear division of labor, functions and competencies between the Branch and the Main Board. Their actions were instead consolidated and the Branch operated within and under the name of Croatian Medical Association. In that year the Branch became independent. The Branch Zagreb is the largest and one of the most active branches of the Croatian Medical Association. At the moment, the Branch brings together 3621 members, regular members--doctors of medicine (2497), doctors of dental medicine (384), retired physicians (710), and associate members (30 specialists with higher education who are not doctors). The Branch is especially accomplished in its activities in the area of professional development of its members and therefore organizes a series of scientific conferences in the framework of continuous education of physicians, allowing its members to acquire necessary points for the extension of their operating license. The choir "Zagrebacki lijecnici pjevaci" (Zagreb Physicians' Choir) of the Croatian Medical Music Society of the CMA and its activities are inseparable from the Branch Zagreb. The Branch is firmly linked to the parent body, the CMA, and thus has a visible impact on the strategy and the activities of the Association as a whole. Most professional societies of the CMA have their headquarters in Zagreb and this is

  3. Fourth international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, H. [ed.] [IVO Group, Vantaa (Finland); Purhonen, H. [ed.] [VTT, Espoo (Finland); Kouhia, V. [ed.] [Lappeenranta Univ. of Technology (Finland)

    1997-12-31

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries.

  4. Causes and characteristics of horizontal positional nystagmus.

    Science.gov (United States)

    Lechner, Corinna; Taylor, Rachael L; Todd, Chris; Macdougall, Hamish; Yavor, Robbie; Halmagyi, G Michael; Welgampola, Miriam S

    2014-05-01

    Direction changing horizontal positional nystagmus can be observed in a variety of central and peripheral vestibular disorders. We tested sixty subjects with horizontal positional nystagmus and vertigo on the Epley Omniax(®) rotator. Monocular video recordings were performed with the right or left ear down, in the supine and prone positions. Nystagmus slow-phase velocity (SPV) was plotted as a function of time. Thirty-one subjects diagnosed with horizontal canalolithiasis had paroxysmal horizontal geotropic nystagmus with the affected ear down (onset 0.8 ± 1 s, range 0-4.9 s, duration 11.7-47.9 s, peak SPV 79 ± 67°/s). The SPV peaked at 5-20 s and declined to 0 by 60 s; at 40 s from onset, the average SPV was 1.8 % of the peak. Nine subjects diagnosed with cupulolithiasis had persistent apogeotropic horizontal nystagmus (onset 0.7 ± 1.4 s, range 0-4.3 s). Peak SPV was 54.2 ± 31.8°/s and 26.6 ± 12.2°/s with unaffected and affected ears down, respectively. At 40 s, the average SPV had decayed to only 81 % (unaffected ear down) and 65 % (affected ear down) of the peak. Twenty subjects were diagnosed with disorders other than benign positional vertigo (BPV) [vestibular migraine (VM), Ménière's Disease, vestibular schwannoma, unilateral or bilateral peripheral vestibular loss]. Subjects with VM (n = 13) had persistent geotropic or apogeotropic horizontal nystagmus. On average, at 40 s from nystagmus onset, the SPV was 61 % of the peak. Two patients with Ménière's Disease had persistent apogeotropic horizontal nystagmus; the peak SPV at 40 s ranged between 28.6 and 49.5 % of the peak. Symptomatic horizontal positional nystagmus can be observed in canalolithiasis, cupulolithiasis and diverse central and peripheral vestibulopathies; its temporal and intensity profile could be helpful in the separation of these entities. PMID:24676938

  5. Fourth international seminar on horizontal steam generators

    International Nuclear Information System (INIS)

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries

  6. Mechanisms of side branching and tip splitting in a model of branching morphogenesis.

    Directory of Open Access Journals (Sweden)

    Yina Guo

    Full Text Available Recent experimental work in lung morphogenesis has described an elegant pattern of branching phenomena. Two primary forms of branching have been identified: side branching and tip splitting. In our previous study of lung branching morphogenesis, we used a 4 variable partial differential equation (PDE, due to Meinhardt, as our mathematical model to describe the reaction and diffusion of morphogens creating those branched patterns. By altering key parameters in the model, we were able to reproduce all the branching styles and the switch between branching modes. Here, we attempt to explain the branching phenomena described above, as growing out of two fundamental instabilities, one in the longitudinal (growth direction and the other in the transverse direction. We begin by decoupling the original branching process into two semi-independent sub-processes, 1 a classic activator/inhibitor system along the growing stalk, and 2 the spatial growth of the stalk. We then reduced the full branching model into an activator/inhibitor model that embeds growth of the stalk as a controllable parameter, to explore the mechanisms that determine different branching patterns. We found that, in this model, 1 side branching results from a pattern-formation instability of the activator/inhibitor subsystem in the longitudinal direction. This instability is far from equilibrium, requiring a large inhomogeneity in the initial conditions. It successively creates periodic activator peaks along the growing stalk, each of which later on migrates out and forms a side branch; 2 tip splitting is due to a Turing-style instability along the transversal direction, that creates the spatial splitting of the activator peak into 2 simultaneously-formed peaks at the growing tip, the occurrence of which requires the widening of the growing stalk. Tip splitting is abolished when transversal stalk widening is prevented; 3 when both instabilities are satisfied, tip bifurcation occurs

  7. Mechanisms of Side Branching and Tip Splitting in a Model of Branching Morphogenesis

    Science.gov (United States)

    Guo, Yina; Sun, Mingzhu; Garfinkel, Alan; Zhao, Xin

    2014-01-01

    Recent experimental work in lung morphogenesis has described an elegant pattern of branching phenomena. Two primary forms of branching have been identified: side branching and tip splitting. In our previous study of lung branching morphogenesis, we used a 4 variable partial differential equation (PDE), due to Meinhardt, as our mathematical model to describe the reaction and diffusion of morphogens creating those branched patterns. By altering key parameters in the model, we were able to reproduce all the branching styles and the switch between branching modes. Here, we attempt to explain the branching phenomena described above, as growing out of two fundamental instabilities, one in the longitudinal (growth) direction and the other in the transverse direction. We begin by decoupling the original branching process into two semi-independent sub-processes, 1) a classic activator/inhibitor system along the growing stalk, and 2) the spatial growth of the stalk. We then reduced the full branching model into an activator/inhibitor model that embeds growth of the stalk as a controllable parameter, to explore the mechanisms that determine different branching patterns. We found that, in this model, 1) side branching results from a pattern-formation instability of the activator/inhibitor subsystem in the longitudinal direction. This instability is far from equilibrium, requiring a large inhomogeneity in the initial conditions. It successively creates periodic activator peaks along the growing stalk, each of which later on migrates out and forms a side branch; 2) tip splitting is due to a Turing-style instability along the transversal direction, that creates the spatial splitting of the activator peak into 2 simultaneously-formed peaks at the growing tip, the occurrence of which requires the widening of the growing stalk. Tip splitting is abolished when transversal stalk widening is prevented; 3) when both instabilities are satisfied, tip bifurcation occurs together with side

  8. Branch architecture, light interception and crown development in saplings of a plagiotropically branching tropical tree, Polyalthia jenkinsii (Annonaceae).

    Science.gov (United States)

    Osada, Noriyuki; Takeda, Hiroshi

    2003-01-01

    To investigate crown development patterns, branch architecture, branch-level light interception, and leaf and branch dynamics were studied in saplings of a plagiotropically branching tree species, Polyalthia jenkinsii Hk. f. & Thoms. (Annonaceae) in a Malaysian rain forest. Lengths of branches and parts of the branches lacking leaves ('bare' branches) were smaller in upper branches than in lower branches within crowns, whereas lengths of 'leafy' parts and the number of leaves per branch were larger in intermediate than in upper and lower branches. Maximum diffuse light absorption (DLA) of individual leaves was not related to sapling height or branch position within crowns, whereas minimum DLA was lower in tall saplings. Accordingly, branch-level light interception was higher in intermediate than in upper and lower branches. The leaf production rate was higher and leaf loss rate was smaller in upper than in intermediate and lower branches. Moreover, the branch production rate of new first-order branches was larger in the upper crowns. Thus, leaf and branch dynamics do not correspond to branch-level light interception in the different canopy zones. As a result of architectural constraints, branches at different vertical positions experience predictable light microenvironments in plagiotropic species. Accordingly, this pattern of carbon allocation among branches might be particularly important for growth and crown development in plagiotropic species. PMID:12495920

  9. 补充支链氨基酸对失眠老年大鼠行为和糖代谢的影响%Effects of branched-chain amino acids supplementation on behaviour and glucose metabolism in aged rats subjected to in- somnia(

    Institute of Scientific and Technical Information of China (English)

    欧阳儒颖; 张济生; 蔡懿灵

    2014-01-01

    Objectives To explore the effects of branched-chain amino acids( BCAA) supplementation on behaviour and glucose metabolism in aged rats subjected to isomnia.Methods Experimental model of isomnia was established by use of sleep deprivation method(flower pot),thirty aged male rats were divided into five groups randomly:C(control)group, 6h(6 hours sleep per day) group, 6hB(6 hours sleep per day and fed fodder enriched with BCAA)group,4h(4 hours sleep per day)group and 4hB group.Re-sults Time of resting on the center lattic,number of make-up and number of excrete were significantly increased in experimental groups compared with C group(PC group>4h group(P0.05).Conpared with C group,the level of FPG in experimential groups were increased apparently (P4h (P<0.05).Conclusions supplementation of BCAA may ameliorates behavior and glucose metabolism in aged rats subjected to isomnia.%目的:探讨补充支链氨基酸( branched-chain amino acids,BCAA)对失眠老年大鼠行为和糖代谢的影响。方法采用小平台水环境的睡眠剥夺方法建立动物失眠模型,30只雄性老年大鼠随机分为对照组( C组)、6h组(每天6小时睡眠组)、6hB组(每天睡眠6小时,进食添加BCAA的饲料),4h组(每天睡眠4小时),4hB组(每天睡眠4小时,进食添加BCAA的饲料)。结果实验组大鼠的修饰行为次数、中央格停留时间、粪便颗粒数均高于C组,差异具有显著性( P<0.05)。且修饰行为次数、中央格停留时间4hB组<4h组(P<0.05);旷场实验得分6h组>C组>4h组,差异具有显著性(P<0.05)。但旷场实验得分、粪便颗粒数6h组与6hB组,4h组与4hB组比较无差异(P>0.05)。与C组比较,实验组的FPG水平显著升高(P<0.05);但4hB组<4h组(P<0.05)。与C组比较4h组和4hB组的血清INS水平显著升高(P<0.05),且4hB组<4h组(P<0.05)。与C组比较,

  10. Agents in branching space-times

    Institute of Scientific and Technical Information of China (English)

    Nuel; Belnap

    2003-01-01

    The aim of this essay Is to make some brief suggestions on the beginnings of a theory of agentsand agency In branching spacetlmes.foe thought Is to combine the ideas of agency as developed agalnst the relatively simple background of branching time with the richer notions of Indetermlnlsm asstructured In the theory of branching space-times.My plan Is to say a little about agency In branchingtime and a little about branchlg spacetlmes,and then ask how the two can be brought together.Atthe end there Is an ...

  11. Measurement of Prominent eta Decay Branching Fractions

    CERN Document Server

    López, A; Méndez, H; Ramírez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Galik, R S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A G; Ernst, J; Ecklund, K M; Severini, H; Love, W; Savinov, V

    2007-01-01

    The decay psi(2S) --> eta J/psi is used to measure, for the first time, all prominent eta-meson branching fractions with the same experiment in the same dataset, thereby providing a consistent treatment of systematics across branching fractions. We present results for eta decays to gamma gamma, pi+pi-pi0, 3 pi0, pi+ pi- gamma, and e+ e- gamma, accounting for 99.9% of all eta decays. The precisions for several of the branching fractions and their ratios are improved. Two channels, pi+ pi- gamma and e+ e- gamma, show results that differ at the level of three standard deviations from those previously determined.

  12. The Life Cycle of Bare Branch Families in China: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Quanbao Jiang

    2013-01-01

    Full Text Available China is characterized by a large number of men who are unable to marry, often referred to as “bare branches.” In this paper, we define the bare branch family and divide its life cycle into three stages: the unmarried co-resident with both parents, co-resident with a surviving parent, and living alone. As the childbearing age of parents increases, the age of a bare branch at the death of his parents decreases, and the duration of his living alone lengthens. An increase in the mother’s childbearing age, holding that of the father constant, shortens the stage of co-residence with both parents, and lengthens the stage of living alone.

  13. Cues for localization in the horizontal plane

    DEFF Research Database (Denmark)

    Jeppesen, Jakob; Møller, Henrik

    2005-01-01

    manipulated in HRTFs used for binaural synthesis of sound in the horizontal plane. The manipulation of cues resulted in HRTFs with cues ranging from correct combinations of spectral information and ITDs to combinations with severely conflicting cues. Both the ITD and the spectral information seem to be...

  14. Stabilities of Parallel Flow and Horizontal Convection

    OpenAIRE

    Sun, Liang

    2009-01-01

    In the first part, the stability of two-dimensional parallel flow is discussed. A more restrictively general stability criterion for inviscid parallel flow is obtained analytically. In the second part, we report the numerical simulations of the partial-penetrating flow in horizontal convection within a squire cavity tank at high Rayleigh numbers $10^7

  15. Comparing cost and performance of horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Pocovi, A.S.; Gustavino, L.L. (Gerencia de Mineria y Geologica de Exploracion, YPF (AR)); Pozzo, A.; Musmarra, J.A. (Gerencia General de Exploracion, YPF, Buenos Aires (AR))

    1991-02-01

    Argentina's state oil company, YPF, was forced through technical and economic constraints to undertake a four-well pilot horizontal drilling program in its Neuquen fields. This article discusses techniques used, the results and costs, and compares them to costs incurred by the area's original vertical wells.

  16. Terrain slugging in near horizontal oilwells

    OpenAIRE

    Fozard, J.

    2001-01-01

    In this thesis we consider the problem of terrain slugging in near horizontal producing wells. We formulate a simple model for stratified two-phase flow, and consider the linear stability of steady states. We then study the possibility of the formation of roll waves, and make a tentative attempt at a resolution of the problem.

  17. Horizontal Axis Levitron--A Physics Demonstration

    Science.gov (United States)

    Michaelis, Max M.

    2014-01-01

    After a brief history of the Levitron, the first horizontal axis Levitron is reported. Because it is easy to operate, it lends itself to educational physics experiments and analogies. Precession and nutation are visualized by reflecting the beam from a laser pointer off the "spignet". Precession is fundamental to nuclear magnetic…

  18. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and...

  19. Third international seminar on horizontal steam generators

    International Nuclear Information System (INIS)

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues

  20. Evaluation of horizontal magnification on panoramic images

    Directory of Open Access Journals (Sweden)

    Maryam Raoof

    2013-01-01

    Full Text Available Aims: This study evaluated the horizontal magnification of images taken from adults and pediatrics with PM 2002 CC Planmeca analogue machine. Materials and Methods: A series of 120 panoramic radiographs were obtained of 60 adults and 60 pediatrics. For all patients, negative impressions were used to make positive casts of the teeth. A caliper was used to measure the maximum mesiodistal length of the buccal surface of all teeth except canines on both casts and radiographs. The horizontal magnification factor was calculated for incisor, premolar, and molar regions by dividing the values obtained from the casts by the values obtained from the radiographs. Statistical Analysis: Independent t-test and one-way analysis of variance (ANOVA were used. Results: The results indicated that with regard to adults, maxillary and mandibular incisor regions, unlike the other two sessions, didn′t show significant difference of the mean magnification of horizontal dimension (P = 0.5. In pediatrics, the comparison between mean magnification factors of all subgroups showed significant difference (P < 0.0001. Despite the adults′ radiographs, the results of pediatrics′ radiographs showed significantly higher magnification than the index listed by the manufacturer of the radiographic machine used. Conclusion: The present study results point to the fact that PM 2002 CC Proline panoramic machine makes possible precise measurements on radiographs of adults′ jaws in the horizontal dimension.

  1. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  2. Flow mapping for ESS horizontal target

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Y.; Kikura, H.; Taishi, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Flow behaviour for ESS horizontal target is studied experimentally using two dimensional water model. A velocity field of stationary flow in reaction zone has been obtained. Three dimensional effect was also studied as a spanwise flow structure. (author) 3 figs., 3 refs.

  3. Horizontally separated 1-in-1 crossing insertions

    Energy Technology Data Exchange (ETDEWEB)

    Syphers, M.J. [Fermi National Accelerator Lab., Batavia, IL (United States)

    1985-10-01

    Previous to this workshop, realistic lattices have been developed for vertically separated l-in-l (e.g., D.E. Johnson, A.A. Garren) and 2-in-1 (e.g., S. Heifets) magnets as well as for horizontally separated 2-in-l magnets (e.g., SSC RDS). Bringing together the widely separated ({approximately}60-70 cm) beams in a reasonable length of tunnel and keeping the dispersion zero at the interaction point has been difficult in the vertical l-in-l case. Most designs have required spacial 2-in-1 quadrupoles near the interaction point where the beams are separated by 15 cm or less. It is not clear that such magnets, as dictated by some of these lattice designs, can easily be built. The purpose of this exercise is to provide a crossing insertion for a realistic lattice which involves horizontally separated l-in-l magnets. The following horizontal crossing insertions, which incorporate the dispersion suppressors and phase trombones into the major arcs, need no special 2-in-1 magnets near the interaction point. The dispersion at the IP created by the horizontal crossing can be cancelled by the dispersion suppressor and one set of triplets.

  4. Branching processes with immigration and related topics

    OpenAIRE

    Li, Zenghu

    2006-01-01

    This is a survey on recent progresses in the study of branching processes with immigration, generalized Ornstein-Uhlenbeck processes and affine Markov processes. We mainly focus on the applications of skew convolution semigroups and the connections in those processes.

  5. Applied Aeroscience and CFD Branch Overview

    Science.gov (United States)

    LeBeau, Gerald J.; Kirk, Benjamin S.

    2014-01-01

    The principal mission of NASA Johnson Space Center is Human Spaceflight. In support of the mission the Applied Aeroscience and CFD Branch has several technical competencies that include aerodynamic characterization, aerothermodynamic heating, rarefied gas dynamics, and decelerator (parachute) systems.

  6. FY 1990 Applied Sciences Branch annual report

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, B.M.; Dippo, P.C. [eds.

    1991-11-01

    The Applied Sciences Branch actively supports the advancement of DOE/SERI goals for the development and implementation of the solar photovoltaic technology. The primary focus of the laboratories is to provide state-of-the-art analytical capabilities for materials and device characterization and fabrication. The branch houses a comprehensive facility which is capable of providing information on the full range of photovoltaic components. A major objective of the branch is to aggressively pursue collaborative research with other government laboratories, universities, and industrial firms for the advancement of photovoltaic technologies. Members of the branch disseminate research findings to the technical community in publications and presentations. This report contains information on surface and interface analysis, materials characterization, development, electro-optical characterization module testing and performance, surface interactions and FTIR spectroscopy.

  7. Residence times of branching diffusion processes

    Science.gov (United States)

    Dumonteil, E.; Mazzolo, A.

    2016-07-01

    The residence time of a branching Brownian process is the amount of time that the mother particle and all its descendants spend inside a domain. Using the Feynman-Kac formalism, we derive the residence-time equation as well as the equations for its moments for a branching diffusion process with an arbitrary number of descendants. This general approach is illustrated with simple examples in free space and in confined geometries where explicit formulas for the moments are obtained within the long time limit. In particular, we study in detail the influence of the branching mechanism on those moments. The present approach can also be applied to investigate other additive functionals of branching Brownian process.

  8. Code 672 observational science branch computer networks

    Science.gov (United States)

    Hancock, D. W.; Shirk, H. G.

    1988-01-01

    In general, networking increases productivity due to the speed of transmission, easy access to remote computers, ability to share files, and increased availability of peripherals. Two different networks within the Observational Science Branch are described in detail.

  9. From configurations to branched configurations and beyond

    OpenAIRE

    Magnot, Jean-Pierre

    2013-01-01

    We propose here a geometric and topological setting for the study of branching effects arising in various fields of research, e.g. in statistical mechanics and turbulence theory. We describe various aspects that appear key points to us, and finish with a limit of such a construction which stand in the dynamics on probability spaces where it seems that branching effects can be fully studied without any adaptation of the framework.

  10. CAST Xi'an Branch Established

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ China Academy of Space Technology (CAST) Xi'an Branch was established on April 8,2008.The new branch consists of the headquarters of the former Xi'an Institute of Space Radio Technology (XISRT) of CAST and five former subsidiaries of the XISRT,i.e.the Institute of Space Electronic Technology,the Institute of Microwave Technology,the Institute of Space Antenna Technology,the Manufacturing Center for Space Electronics and Civilian High-tech Company.

  11. AGB (asymptotic giant branch): Star evolution

    Energy Technology Data Exchange (ETDEWEB)

    Becker, S.A.

    1987-01-01

    Asymptotic giant branch stars are red supergiant stars of low-to-intermediate mass. This class of stars is of particular interest because many of these stars can have nuclear processed material brought up repeatedly from the deep interior to the surface where it can be observed. A review of recent theoretical and observational work on stars undergoing the asymptotic giant branch phase is presented. 41 refs.

  12. Branch retinal artery occlusion in Susac's syndrome

    Directory of Open Access Journals (Sweden)

    Ricardo Evangelista Marrocos de Aragão

    2015-02-01

    Full Text Available Susac's syndrome is a rare disease attribuited to a microangiopathy involving the arterioles of the cochlea, retina and brain. Encefalopathy, hearing loss, and visual deficits are the hallmarks of the disease. Visual loss is due to multiple, recurrent branch arterial retinal occlusions. We report a case of a 20-year-old women with Susac syndrome presented with peripheral vestibular syndrome, hearing loss, ataxia, vertigo, and vision loss due occlusion of the retinal branch artery.

  13. Branch and Bound Algorithm for Multiprocessor Scheduling

    OpenAIRE

    Rahman, Mostafizur

    2009-01-01

    The multiprocessor task graph scheduling problem has been extensively studied asacademic optimization problem which occurs in optimizing the execution time of parallelalgorithm with parallel computer. The problem is already being known as one of the NPhardproblems. There are many good approaches made with many optimizing algorithmto find out the optimum solution for this problem with less computational time. One ofthem is branch and bound algorithm.In this paper, we propose a branch and bound...

  14. AGB [asymptotic giant branch]: Star evolution

    International Nuclear Information System (INIS)

    Asymptotic giant branch stars are red supergiant stars of low-to-intermediate mass. This class of stars is of particular interest because many of these stars can have nuclear processed material brought up repeatedly from the deep interior to the surface where it can be observed. A review of recent theoretical and observational work on stars undergoing the asymptotic giant branch phase is presented. 41 refs

  15. Comparative efficiency analysis of Portuguese bank branches

    OpenAIRE

    Portela, Maria; Thanassoulis, Emmanuel

    2006-01-01

    The advent of Internet banking and phone banking is changing the role of bank branches from a predominantly transaction- based one to a sales-oriented role. This paper reports on an assessment of the branches of a Portuguese bank in terms of their performance in their new roles in three different areas: Their efficiency in fostering the use of new transaction channels, their efficiency in increasing sales and their customer base, and their efficiency in generating profits. Service qu...

  16. Comparative performance analysis of portuguese bank branches

    OpenAIRE

    Portela, Maria; Thanassoulis, Emmanuel

    2003-01-01

    The advent of Internet banking and phone banking is changing the role of bank branches from a predominantly transaction-based one to a sales-oriented role. This paper reports on an assessment of the branches of a Portuguese bank in terms of their performance in their new roles in three different areas: Their effectiveness in fostering the use of new transaction channels such as the internet and the telephone, their effectiveness in increasing sales and their customer base, and the...

  17. Fiber-Optic Communication Technology Branching Devices

    Science.gov (United States)

    Williams, J. C.

    1985-02-01

    This tutorial review of fiber-optic branching devices covers example uses of branching devices, device types, device-performance characteristics, examples of current technology, and system-design methodology. The discussion is limited to passive single- and multimode devices fabricated from optical fibers or graded-index components. Integrated-optic, wavelength-division-multiplexing, and polarization-selective devices are not specifically addressed.

  18. All change at the CERN UBS branch

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    UBS branches across the country are being modernised, and the CERN branch is no exception. The Bulletin brings you a preview of the project, which will get under way in January 2013.   Mock-up of the renovated UBS branch. The changes at the UBS branch in CERN's Main Building will be no simple facelift. The entire bank will be renovated, transforming the present relatively confined premises into an open and attractive area. "The renovation of the UBS branches is part of a wider campaign designed to further enhance our customer relations," explains Ezio Mangia, the head of the CERN branch.  The UBS bank currently occupies three sets of premises in CERN's Main Building (two on the ground floor and one in the basement). "By the end of the work, which is scheduled to be completed by the middle of next year, CERN customers will benefit from a new area with open-plan counters and "hole-in-the-wall" machines accessible to...

  19. Paleo magnetism of the Para de Minas mafic dike swarm, west of Belo Horizonte, MG, Brazil

    International Nuclear Information System (INIS)

    Preliminary paleo magnetic results from 64 oriented hand samples belonging to 20 un metamorphosed dikes from west of Belo Horizonte, Minas Gerais are presented. The paleo magnetic analysis showed a complex magnetic behavior after AF (alternating field) and thermal treatments, when stable but incoherent directions were disclosed by samples of many dikes. 40 Ar/39 Ar age determinations on these granulite are in progress in order to constrain the age of this component of magnetization. (author)

  20. Gravity-dependent regulation of red light induced moss protonemata branching and gametophore bud formation

    Science.gov (United States)

    Ripetskyj, R. T.; Kit, N. A.

    Isolated leafy shoots of the moss Pottia intermedia positioned horizontally on the agar surface in vertically oriented petri dishes regenerate unbranching negatively gravitropic protonemata on upper side of the regenerant. Gravity determines the site of regeneration not the process itself. White light of low intensity unsufficient to induce positive phototropism of dark-grown protonemata can, however, provoke their branching and gametophore bud formation (Ripetskyj et al., 1998; 1999). The presented experiments have been carried out with red light in Biological Research in Canisters/Light Emitting Diode (BRIC/LED) hardware developed at Kennedy Space Center, USA. Seven-day-old dark-grown negatively gravitropic secondary P. intermedia protonemata were positioned differently with respect to gravity vector and to the source of red light of low, 1 or 2 μ mol\\cdot m-2\\cdot s-1, intensities. The light induced intensive branching of the protonemata and gametophore bud formation initiation site of both processes as well as the direction of growth of branches and buds being depent on the position of protonemata with respect to gravity and light vectors. Vertically positioned, i.e. ungravistimulated, dark grown protonemata illuminated from one side with red light of 2 μ mol\\cdot m-2\\cdot s-1 intensity produced 96,9 ± 2,2% of side branches and buds growing directly towards the light source from the lit protonema side. Horizontally disposed protonemata irradiated from below with red light of the same intensity regenerate 31,7 ± 3,9% of branches and buds on the upper, i.e. shaded protonemata side, the upward growth of which should undoubtedly be determined by gravity. In vertically disposed protonemata illuminated with red light of 1 μ mol\\cdot m-2\\cdot s-1 intensity from aside 31,9 ± 5,5% of side branches and buds arised on shaded protonema side and grew away from the light. Illumination of the protonemata in horizontal position from below increased the number of

  1. Articulating Support for Horizontal Resistive Exercise

    Science.gov (United States)

    Gundo, Daniel; Schaffner, Grant; Bentley, Jason; Loehr, James A.

    2005-01-01

    A versatile mechanical device provides support for a user engaged in any of a variety of resistive exercises in a substantially horizontal orientation. The unique features and versatility of the device promise to be useful in bedrest studies, rehabilitation, and specialized strength training. The device affords a capability for selectively loading and unloading of portions of the user s body through its support mechanisms, so that specific parts of the body can be trained with little or no effect on other parts that may be disabled or in the process of recovery from injury. Thus, the device is ideal for rehabilitation exercise programs prescribed by physicians and physical therapists. The capability for selective loading and support also offers potential benefits to strength and conditioning trainers and athletes who wish to selectively strengthen selected parts. The principal innovative aspect of the device is that it supports the subject s weight while enabling the subject, lying substantially horizontally, to perform an exercise that closely approximates a full standing squat. The device includes mechanisms that support the subject in such a way that the hips are free to translate both horizontally and vertically and are free to rotate about the line connecting the hips. At the same time, the shoulders are free to translate horizontally while the upper back is free to rotate about the line connecting the shoulders. Among the mechanisms for hip motion and support is a counterbalance that offsets the weight of the subject as the subject s pelvis translates horizontally and vertically and rotates the pelvis about the line connecting the hips. The counterbalance is connected to a pelvic support system that allows these pelvic movements. The subject is also supported at the shoulder by a mechanism that can tilt to provide continuous support of the upper back while allowing the rotation required for arching the back as the pelvis is displaced. The shoulder support

  2. A face detection bias for horizontal orientations develops in middle childhood

    Directory of Open Access Journals (Sweden)

    Benjamin J Balas

    2015-06-01

    Full Text Available Faces are complex stimuli that can be described via intuitive facial features like the eyes, nose, and mouth, configural features like the distances between facial landmarks, and features that correspond to computations performed in the early visual system (e.g. oriented edges. With regard to this latter category of descriptors, adult face recognition relies disproportionately on information in specific spatial frequency and orientation bands: Many recognition tasks are performed more accurately when adults have access to mid-range spatial frequencies (8-16 cycles/face and horizontal orientations (Dakin & Watt, 2009. In the current study, we examined how this information bias develops in middle childhood. We recruited children between the ages of 5-10 years old to participate in a simple categorization task that required them to label images according to whether they depicted a face or a house. Critically, children were presented with face and house images comprised either of primarily horizontal orientation energy, primarily vertical orientation energy, or both horizontal and vertical orientation energy. We predicted that any bias favoring horizontal information over vertical should be more evident in faces than in houses, and also that older children would be more likely to show such a bias than younger children. We designed our categorization task to be sufficiently easy that children would perform at near-ceiling accuracy levels, but with variation in response times that would reflect how they rely on different orientations as a function of age and object category. We found that horizontal bias for face detection (but not house detection correlated significantly with age, suggesting an emergent category-specific bias for horizontal orientation energy that develops during middle childhood. These results thus suggest that the tuning of high-level recognition to specific low-level visual features takes take place over several years of visual

  3. HORIZONTAL DRILLING ACTIVITY IN HUNGARY AND SPECIAL QUESTIONS OF BLOWOUT PREVENTION IN HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Jozsef Szepesi

    1996-12-01

    Full Text Available Described is horizontal drilling in the world and data on such activity in Hungary. Results show that there is an increase of such activity in spite of complex problems in drilling and completion of horizontal wells. Since these wells are often drilled in partialy exhausted hydrocarbon fluid reservoirs with slightly over-balanced or even with under-balanced conditions, there is an increased danger of blowouts. Prevention methods and suggested procedures are elaborated.

  4. HORIZONTAL DRILLING ACTIVITY IN HUNGARY AND SPECIAL QUESTIONS OF BLOWOUT PREVENTION IN HORIZONTAL WELLS

    OpenAIRE

    Jozsef Szepesi

    1996-01-01

    Described is horizontal drilling in the world and data on such activity in Hungary. Results show that there is an increase of such activity in spite of complex problems in drilling and completion of horizontal wells. Since these wells are often drilled in partialy exhausted hydrocarbon fluid reservoirs with slightly over-balanced or even with under-balanced conditions, there is an increased danger of blowouts. Prevention methods and suggested procedures are elaborated.

  5. Northwestern Branch of Mangala Vallis

    Science.gov (United States)

    2002-01-01

    (Released 12 June 2002) The Science One of the many branches of the Mangala Vallis channel system is seen in this image. The water that likely carved the channels emerged from a huge graben or fracture almost 1000 km to the south. The THEMIS image shows where one of the channels exits the cratered highlands terrain onto the lowland plains. A bright scarp marks the transition between the two terrain types and demonstrates that in this location the highlands terrain is being eroded back. Note how the floor of the main channel appears to be at the same level as the lowland terrain, suggestive of a base level where erosion is no longer effective. Most of the steep slope faces in the image display darker slope streaks that are thought to be dust avalanche scars and indicate that a relatively thick mantle of dust is present in this region. Wind-sculpted ridges known as yardangs cover many of the surfaces throughout the area as shown by images from the Mars Global Surveyor mission. Most of them are at the limit of resolution in the THEMIS image but some are evident on the floor of the main channel at the point at which a smaller side channel enters. In this location they appear to extend right up to the base of the channel wall, giving the appearance that they are emerging from underneath the thick pile of material into which the channel is eroded. This suggests a geologic history in which a preexisting landscape of eroded yardangs was covered over by a thick pile of younger material that is now eroding back down to the original level. Alternatively, it is possible that the yardangs formed more recently at the abrupt transition between the channel floor and wall. More analysis is necessary to sort out the story. The Story This channel system is named 'Mangala,' the word for Mars in Sanskrit, a language of the Hindus of India that goes back more than 4,000 years, with written literature almost as long. Great epic tales have been written in this language, and Odyssey is

  6. Horizontal gene transfer between bacteria and animals.

    Science.gov (United States)

    Dunning Hotopp, Julie C

    2011-04-01

    Horizontal gene transfer is increasingly described between bacteria and animals. Such transfers that are vertically inherited have the potential to influence the evolution of animals. One classic example is the transfer of DNA from mitochondria and chloroplasts to the nucleus after the acquisition of these organelles by eukaryotes. Even today, many of the described instances of bacteria-to-animal transfer occur as part of intimate relationships such as those of endosymbionts and their invertebrate hosts, particularly insects and nematodes, while numerous transfers are also found in asexual animals. Both of these observations are consistent with modern evolutionary theory, in particular the serial endosymbiotic theory and Muller's ratchet. Although it is tempting to suggest that these particular lifestyles promote horizontal gene transfer, it is difficult to ascertain given the nonrandom sampling of animal genome sequencing projects and the lack of a systematic analysis of animal genomes for such transfers. PMID:21334091

  7. Formation evaluation of a horizontal well

    International Nuclear Information System (INIS)

    In Upper Zakum Field, the interest in horizontal drilling has continued. A second horizontal well was drilled during the second half of 1989. This necessitated running logging tools for well control and to evaluate the reservoir characteristics. The logging tool selected for this well is that of Sperry-Sun. Tools configuration and tolerance were found to fulfil SADCO's requirements and specifications. This paper reports on the services produced which included Measurement While Drilling (MWD) directional services and RLL (Recorded Lithology Logging). The RLL services cover Dual Gamma Ray (DGR), Electromagnetic Wave Resistivity (EWR) and Compensated Neutron Porosity (CN porosity). All the RLL tools were an integrated part of the Bottom Hole Drilling Assembly. Data acquired while surveying was recorded in a recording sub down-hole and retrieved when the tools were up at the surface. A PC assisted quick look interpretation was carried out using Archie's equation in shale free limestone to calculate: Effective porosity, Water Saturation and, Bulk water volume

  8. Ballistocardiography in sitting and horizontal positions

    International Nuclear Information System (INIS)

    The purpose of this study is to examine the effect of posture in the sitting and supine positions on ballistocardiography (BCG) measurements by using EMFi (electromechanical film) sensors. The experiment, measuring the subject's electrocardiography (ECG), BCG and carotid pulse (CP) signal, was repeated in the sitting and different horizontal positions. Additionally, the duration and the amplitudes of the BCG and CP signal components were studied. Certain properties of BCG differed significantly in the sitting and horizontal positions. Amplitudes of measured signals were larger, and time intervals were greater in the sitting position compared to the supine position. Thus, posture significantly influences cardiac performance evaluated by BCG. Sitting and supine positions are clearly distinguishable in the BCG signal. This provides new methods for evaluation of the hemodynamic changes induced by the body position

  9. Detecting series periodicity with horizontal visibility graphs

    CERN Document Server

    Núñez, Angel M; Valero, Eusebio; Gómez, Jose Patricio; Luque, Bartolo

    2011-01-01

    The horizontal visibility algorithm has been recently introduced as a mapping between time series and networks. The challenge lies in characterizing the structure of time series (and the processes that generated those series) using the powerful tools of graph theory. Recent works have shown that the visibility graphs inherit several degrees of correlations from their associated series, and therefore such graph theoretical characterization is in principle possible. However, both the mathematical grounding of this promising theory and its applications are on its infancy. Following this line, here we address the question of detecting hidden periodicity in series polluted with a certain amount of noise. We first put forward some generic properties of horizontal visibility graphs which allow us to define a (graph theoretical) noise reduction filter. Accordingly, we evaluate its performance for the task of calculating the period of noisy periodic signals, and compare our results with standard time domain (autocorre...

  10. Throwing and jumping for maximum horizontal range

    CERN Document Server

    Linthorne, N P

    2006-01-01

    Optimum projection angles for achieving maximum horizontal range in throwing and jumping events are considerably less than 45 degrees. This unexpected result arise because an athlete can generate a greater projection velocity at low projection angles than at high angles. The range of a projectile is strongly dependent on projection speed and so the optimum projection angle is biased towards low projection angles. Here we examine the velocity-angle relation and the optimum projection angle in selected throwing and jumping events.

  11. Cues for localization in the horizontal plane

    DEFF Research Database (Denmark)

    Jeppesen, Jakob; Møller, Henrik

    2005-01-01

    Spatial localization of sound is often described as unconscious evaluation of cues given by the interaural time difference (ITD) and the spectral information of the sound that reaches the two ears. Our present knowledge suggests the hypothesis that the ITD roughly determines the cone of the perce...... independently in HRTFs used for binaural synthesis. The ITD seems to be dominant for localization in the horizontal plane even when the spectral information is severely degraded....

  12. Maximal liquid bridges between horizontal cylinders

    OpenAIRE

    Cooray, Himantha; Huppert, Herbert E.; Neufeld, Jerome A

    2016-01-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces due to surface tension and hydrostatic pressure which balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can ...

  13. Neutrino masses, magnetic moments, and horizontal symmetries

    International Nuclear Information System (INIS)

    We investigate the general structure of the neutrino mass and magnetic matrices in the presence of an unbroken horizontal symmetry. In particular, we study the compatibility of masslessness induced by such a symmetry and a non-zero magnetic moment. We show that in this case at least two of the charged leptons must have equal masses. Furthermore, we give a general definition of Dirac neutrinos and demonstrate that they are not necessarily associated with a lepton number. (Author) 15 refs

  14. Horizontal mergers, entry, and efficiency defences

    OpenAIRE

    Spector, David

    2002-01-01

    This paper addresses the effect of horizontal mergers on prices. It is shown that if firms compete in quantities and marginal costs are nondecreasing, any profitable merger failing to generate technological synergies must harm consumers through higher prices, irrespective of entry conditions in the industry. However this result does not hold if products are differentiated and firms compete in prices. The implications for merger policy are discussed.

  15. Horizontal vibrations of piles in a centrifuge

    International Nuclear Information System (INIS)

    The aim of the thesis is the study of soil dynamics for important structures like nuclear power plants, offshore platforms, dams etc. Experimental results of horizontal vibrations on a pile partially anchored in a soil scale model put into a centrifuge are presented. Mechanical similitude conditions from equilibrium equations or rheologic laws are described. After a description of testing equipment (centrifuge, electrodynamic excitator) experimental results are interpreted with a model. Non-linearities on frequency response curves are characterized

  16. Horizontal gene transfer between bacteria and animals

    OpenAIRE

    Dunning Hotopp, Julie C.

    2011-01-01

    Horizontal gene transfer is increasingly described between bacteria and animals. Such transfers that are vertically inherited have the potential to influence the evolution of animals. One classic example is the transfer of DNA from mitochondria and chloroplasts to the nucleus after the acquisition of these organelles by eukaryotes. Even today, many of the described instances of bacteria to animal transfer occur as part of intimate relationships like those of endosymbionts and their invertebra...

  17. Productivity and Injectivity of Horizontal Wells

    International Nuclear Information System (INIS)

    The work on modeling hydraulically fractured horizontal wells has moved forward. A literature review on the subject was done and some of the existing models have been coded and applied to example problems for evaluation purposes. Previous work on the elects of heterogeneities on the performance of horizontal wells was continued by conducting a sensitivity study on various parameters that were kept constant in the earlier study. For example, we have studied the elect of gas cap and aquifer size, well location, fluid viscosity, etc. The experimental work on using horizontal wells as injectors and producers in a gas injection gravity drainage process continued. New and repeat experiments were conducted. Work on streamline grids was advanced by considering example problems with highly distorted grids which cannot be directly used for flow simulation. Grid smoothing and domain mapping techniques were investigated to handle such situations. A technique was developed for the computation o f well index with consideration to wellbore pressure drop. A recently developed reservoir/wellbore coupling model was used for this purpose

  18. c horizontal convexity on Carnot groups

    CERN Document Server

    Calogero, Andrea

    2010-01-01

    Given a real-valued function $c$ defined on the cartesian product of a generic Carnot group $\\G$ and the first layer $V_1$ of its Lie algebra, we introduce a notion of $c$ horizontal convex ($c$ H-convex) function on $\\G$ as the supremum of a suitable family of affine functions; this family is defined pointwisely, and depends strictly on the horizontal structure of the group. This abstract approach provides $c$ H-convex functions that, under appropriate assumptions on $c,$ are characterized by the nonemptiness of the $c$ H-subdifferential and, above all, are locally H-semiconvex, thereby admitting horizontal derivatives almost everywhere. It is noteworthy that such functions can be recovered via a Rockafellar technique, starting from a suitable notion of $c$ H-cyclic monotonicity for maps. In the particular case where $c(g,v)=,$ we obtain the well-known weakly H-convex functions introduced by Danielli, Garofalo and Nhieu. Finally, we suggest a possible application to optimal mass transportation.

  19. Airway branching morphogenesis in three dimensional culture

    Directory of Open Access Journals (Sweden)

    Gudjonsson Thorarinn

    2010-11-01

    Full Text Available Abstract Background Lungs develop from the fetal digestive tract where epithelium invades the vascular rich stroma in a process called branching morphogenesis. In organogenesis, endothelial cells have been shown to be important for morphogenesis and the maintenance of organ structure. The aim of this study was to recapitulate human lung morphogenesis in vitro by establishing a three dimensional (3D co-culture model where lung epithelial cells were cultured in endothelial-rich stroma. Methods We used a human bronchial epithelial cell line (VA10 recently developed in our laboratory. This cell line cell line maintains a predominant basal cell phenotype, expressing p63 and other basal markers such as cytokeratin-5 and -14. Here, we cultured VA10 with human umbilical vein endothelial cells (HUVECs, to mimic the close interaction between these cell types during lung development. Morphogenesis and differentiation was monitored by phase contrast microscopy, immunostainings and confocal imaging. Results We found that in co-culture with endothelial cells, the VA10 cells generated bronchioalveolar like structures, suggesting that lung epithelial branching is facilitated by the presence of endothelial cells. The VA10 derived epithelial structures display various complex patterns of branching and show partial alveolar type-II differentiation with pro-Surfactant-C expression. The epithelial origin of the branching VA10 colonies was confirmed by immunostaining. These bronchioalveolar-like structures were polarized with respect to integrin expression at the cell-matrix interface. The endothelial-induced branching was mediated by soluble factors. Furthermore, fibroblast growth factor receptor-2 (FGFR-2 and sprouty-2 were expressed at the growing tips of the branching structures and the branching was inhibited by the FGFR-small molecule inhibitor SU5402. Discussion In this study we show that a human lung epithelial cell line can be induced by endothelial cells to

  20. Facial fractures: a 1-year retrospective study in a hospital in Belo Horizonte Fraturas de face: um estudo retrospectivo de 1 ano em um hospital de Belo Horizonte

    OpenAIRE

    Bruno Ramos Chrcanovic; Belini Freire-Maia; Leandro Napier de Souza; Vasco de Oliveira Araújo; Mauro Henrique Nogueira Guimarães de Abreu

    2004-01-01

    A retrospective study was performed to assess facial fractures in patients treated at a public hospital in Belo Horizonte, in 2000. The data collected included age, gender, etiology, distribution of maxillofacial trauma considering day of the week and month, anatomic site of the fracture, and treatment. The analyses involved descriptive statistics and chi-squared test, Bonferroni test and analysis of variance. A total of 1,326 facial fractures were found in 911 patients. Most fractures occurr...

  1. The Future of Washington's Branch Campuses. HECB Report on Branch Campus Development Plans-HB 2707

    Science.gov (United States)

    Washington Higher Education Coordinating Board, 2005

    2005-01-01

    Washington's research university branch campuses were created in 1989 to increase opportunities for students in several regions of the state to complete their baccalaureate and graduate-level studies at public universities close to their homes. Currently, the University of Washington operates branch campuses in Bothell and Tacoma. The Bothell…

  2. The effect of horizontal versus vertical task presentation on children's performance in coordinate tasks.

    Science.gov (United States)

    Worsfold, Naomi; Davis, Alyson; De Bruyn, Bart

    2008-01-01

    Empirical work on children's ability to understand spatial coordinates has focused on the factors that increase children's proficiency. When interpreting performance, it should be considered that presenting a coordinate task on a horizontal surface might constrain the responses that children make because some target positions are further away from the child than others. Vertical task presentation removes this constraint. Children aged 3 to 9 years were presented with an interpretative coordinate task administered on a touchscreen, presented in an egocentric-vertical position or egocentric-horizontal position. The results show that for 5- to 7-year-old children vertical presentation led to far more correct responses than horizontal presentation. Analysis of the children's errors suggests that this may be due to the fact that vertical presentation suppresses children's bias towards responding in relation to one rather than both coordinates. Taken together these findings contribute to understanding why children's performance in xy coordination tasks is highly contextually sensitive. PMID:19189731

  3. Measurement of tau lepton branching fractions

    International Nuclear Information System (INIS)

    We present τ- lepton branching fraction measurements based on data from the TPC/Two-Gamma detector at PEP. Using a sample ofτ- → ντK-π+π- events, we examine the resonance structure of the K-π+π- system and obtain the first measurements of branching fractions for τ- → ντK1-(1270) and τ- → ντK1-(1400). We also describe a complete set of branching fraction measurements in which all the decays of the τ- lepton are separated into classes defined by the identities of the charged particles and an estimate of the number of neutrals. This is the first such global measurement with decay classes defined by the four possible charged particle species, e, μ, π, and K

  4. Geometry optimization of branchings in vascular networks

    Science.gov (United States)

    Khamassi, Jamel; Bierwisch, Claas; Pelz, Peter

    2016-06-01

    Progress has been made in developing manufacturing technologies which enable the fabrication of artificial vascular networks for tissue cultivation. However, those networks are rudimentary designed with respect to their geometry. This restricts long-term biological functionality of vascular cells which depends on geometry-related fluid mechanical stimuli and the avoidance of vessel occlusion. In the present work, a bioinspired geometry optimization for branchings in artificial vascular networks has been conducted. The analysis could be simplified by exploiting self-similarity properties of the system. Design rules in the form of two geometrical parameters, i.e., the branching angle and the radius ratio of the daughter branches, are derived using the wall shear stress as command variable. The numerical values of these parameters are within the range of experimental observations. Those design rules are not only beneficial for tissue engineering applications. Moreover, they can be used as indicators for diagnoses of vascular diseases or for the layout of vascular grafts.

  5. The helium-rich subdwarf CPD-20 1123: a post-common envelope binary evolving onto the extended horizontal branch

    CERN Document Server

    N, Naslim; Jeffery, C S; Behara, N T; Woolf, V M; Classen, L

    2012-01-01

    Subluminous B stars come in a variety of flavours including single stars, close and wide binaries, and pulsating and non-pulsating variables. A majority have helium-poor surfaces (helium by number nHe90%). A small number have an intermediate surface helium abundance (~ 10 - 30%), accompanied by peculiar abundances of other elements. The questions posed are i) whether these abundance peculiarities are associated with radiatively-driven and time-dependent stratification of elements within the photosphere as the star evolves from an helium-enriched progenitor to become a normal helium-poor sdB star, and ii) whether these phenomena occur only in single sdB stars or are also associated with sdB stars in binaries. We present a fine analysis of the bright intermediate-helium sdB star CPD-20 1123 (Albus 1) which shows it to be cool, for a hot subdwarf, with Teff~23\\,000 K and with a surface helium abundance ~17% by number. Other elements do not show extraordinary anomalies; in common with majority sdB stars, carbon a...

  6. The helium-rich subdwarf CPD-20 1123: a post-common envelope binary evolving onto the extended horizontal branch

    OpenAIRE

    Naslim, N; Geier, S.; Jeffery, C. S.; Behara, N.T.; Woolf, V. M.; Classen, L.

    2012-01-01

    Subluminous B stars come in a variety of flavours including single stars, close and wide binaries, and pulsating and non-pulsating variables. A majority have helium-poor surfaces (helium by number nHe90%). A small number have an intermediate surface helium abundance (~ 10 - 30%), accompanied by peculiar abundances of other elements. The questions posed are i) whether these abundance peculiarities are associated with radiatively-driven and time-dependent stratification of elements within the p...

  7. [Correction of the retrognathic mandible using vertical sectioning of the horizontal branches and the insertion of grafts].

    Science.gov (United States)

    Gacon, J; Ribault, J Y; Roubaudi, G; Pernice, L

    1990-01-01

    Lengthening of the anterior mandibular arc using iliac bone grafts inserted between the canines and first pre-molars is the treatment of choice for certain cases of mandibular retrognathism PMID:2130475

  8. RELATIONSHIPS AMONG SPRINT VELOCITIES, HORIZONTAL GROUND REACTION FORCE, AND ISOKINETIC TRUNK STRENGTH VARIABLES

    Directory of Open Access Journals (Sweden)

    Kale Mehmet

    2013-12-01

    Full Text Available The purpose of this study was to investigate the relationships among sprint velocities, horizontal ground reaction force, and isokinetic trunk strength variables. Voluntary 19 athletes were participated to the study [age (year= 20.9±2.3, training age (month= 91.3±48.2, body height (cm= 173.1±6.5, body weight (kg= 64.7±8.4] from different sports including in explosive strength. Sprints (10m, 20m, 30m, and 40m were tested on a non-motorized treadmill. Velocities (V10m, V20m, V30m, and V40m and horizontal ground reaction forces (HGRF-10m, HGRF-20m, HGRF-30m, and HGRF-40m of the sprints were calculated. Isokinetic trunk strength criteria (flexion-extension peak torques at 3 different angular velocities (30o.s-1, 90o.s-1, and 120o.s-1 were tested. Pearson Correlation Coefficient was used for statistical analysis. Probability level was p≤0.05. All sprint velocities was correlated with all horizontal ground reaction forces (except the correlation between V10m and HGRF-20m and all isokinetic trunk flexion-extension peak torques (except the correlation between V10m and isokinetic trunk flexion peak torque at 120o.s-1. Statistically highest significant correlations have been found between V40m and all horizontal ground reaction forces and also between V40m and isokinetic trunk flexion-extension peak torques (30o.s-1, 90o.s-1, and 120o.s-1. There were significant relationships of horizontal ground reaction forces with isokinetic trunk extension-flexion peak torques at 30o.s-1, 90o.s-1, and 120o.s-1. In conclusion, isokinetic trunk flexion and extension strength values are crucial for improving sprint acceleration and horizontal component of ground reaction force.

  9. Study of the Local Horizon. (Spanish Title: Estudio del Horizonte Local.) Estudo do Horizonte Local

    Science.gov (United States)

    Ros, Rosa M.

    2009-12-01

    The study of the horizon is fundamental to easy the first observations of the students at any education center. A simple model, to be developed in each center, allows to easy the study and comprehension of the rudiments of astronomy. The constructed model is presented in turn as a simple equatorial clock, other models (horizontal and vertical) may be constructed starting from it. El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical). O estudo do horizonte é fundamental para facilitar as primeiras observações dos alunos num centro educativo. Um modelo simples, que deve ser feito para cada centro, permite facilitar o estudo e a compreensão dos primeiros rudimentos astronômicos. O modelo construído apresenta-se, por sua vez, como um modelo simples de relógio equatorial e a partir dele pode-se construir outros modelos (horizontal e vertical)

  10. Explicit horizontal open books on some Seifert fibered 3--manifolds

    OpenAIRE

    Ozbagci, Burak

    2006-01-01

    We describe explicit horizontal open books on some Seifert fibered 3--manifolds. We show that the contact structures compatible with these horizontal open books are Stein fillable and horizontal as well. Moreover we draw surgery diagrams for some of these contact structures.

  11. The Problem-Solving Skills of the Teachers in Various Branches

    Science.gov (United States)

    Temel, Veysel

    2015-01-01

    The aim of this study was to determine the problem-solving skills of the teachers in various branches in Çat town of Erzurum Province in Turkey, using some variables. A total of 153 teachers (84 females, 69 males and age: 1.6536±0.72837) from different departments participated in the study. Problem Solving Inventory, developed by Heppner and…

  12. Branch and Bound Experiments in Convex Nonlinear Integer Programming

    OpenAIRE

    Omprakash K. Gupta; Ravindran, A

    1985-01-01

    The branch and bound principle has long been established as an effective computational tool for solving mixed integer linear programming problems. This paper investigates the computational feasibility of branch and bound methods in solving convex nonlinear integer programming problems. The efficiency of a branch and bound method often depends on the rules used for selecting the branching variables and branching nodes. Among others, the concepts of pseudo-costs and estimations are implemented ...

  13. Effect of left bundle branch block on TIMI frame count

    OpenAIRE

    Hatice Tolunay; Ahmet Kasapkara; İsa Öner Yüksel; Nurcan Başar; Ayşe Saatcı Yaşar; Mehmet Bilge

    2010-01-01

    Aim: Left bundle branch block is an independent risk factorfor cardiac mortality. In this study we aimed to evaluatecoronary blood flow with TIMI frame count in patients with left bundle branch block and angiographically proven normal coronary arteries.Materials and methods: We retrospectively studied 17 patients with left bundle branch block and as a control group 16 patients without left bundle branch block. All patientshad angiographically proven normal coronary arteries.Left bundle branch...

  14. A Cadaveric Study of the Branching Pattern and Diameter of the Genicular Arteries: A Focus on the Middle Genicular Artery.

    Science.gov (United States)

    Shahid, Shahab; Saghir, Noman; Cawley, Oliver; Saujani, Shyamal

    2015-10-01

    The aim of the study was to gain an appreciation of the variation in the branching pattern and diameter of the genicular arteries arising directly from the popliteal artery (PA), namely, the superior medial genicular artery (SMGA), superior lateral genicular artery (SLGA), inferior medial genicular artery (IMGA), inferior lateral genicular artery (ILGA), and middle genicular artery (MGA). Twenty cadaveric knees aged between 62 and 92 years were dissected. A posterior midline vertical incision was used to gain access to the PA. The diameter of the PA, the sequence of branching, and subsequent diameter of genicular vessels and common trunks were recorded. PA average diameter was 7.9 mm. The SMGA (1.6-mm diameter) was the first branch in 45% and the second branch in 20%, and in seven limbs it arose from a common trunk with the SLGA. The SLGA was the second branch in 30% and the first branch in 25%, and it branched from a common trunk in 45%. The MGA (1.1-mm diameter) arose as the second branch in four knees and as the third branch in eight knees. It arose from a common trunk in eight knees, either with a superior genicular (three knees) or with an inferior genicular (five knees). The IMGA (1.5-mm diameter) was the third branch in 25%, the fourth branch in 35%, and the fifth branch in 15%. In five cases, it arose from a common trunk (25%). The ILGA (1.4-mm diameter) was the third branch in 15%, the fourth branch in 30%, and the fifth branch in 25%. It arose from a common trunk in six knees. These trunks also gave rise to the IMGA in all cases. There is extensive variation in the branching pattern and diameter of the genicular arteries differing from textbook descriptions. An awareness of vascular variation is imperative for preservation of the blood supply to the knee, which may promote recovery after anterior cruciate ligament reconstruction and popliteal aneurysm repair. PMID:25892007

  15. Boring and lining horizontal emplacement holes

    International Nuclear Information System (INIS)

    Systems for and techniques for constructing suitable emplacement holes are being considered for an underground nuclear waste repository. This study is an investigation of methods to bore and line horizontal boreholes of varying lengths. The development prototype boring machine already designed has been selected to bore the long holes (350 ft.), while the method selected to bore short holes, 42, 58, and 75 ft. involves two separate systems: one to bore the hole, the other to line the hole. The systems described in this report are not off-the-shelf, but represent a reasonable extension of current technology. 2 refs., 6 figs., 12 tabs

  16. Horizontal axis Levitron—a physics demonstration

    Science.gov (United States)

    Michaelis, Max M.

    2014-01-01

    After a brief history of the Levitron, the first horizontal axis Levitron is reported. Because it is easy to operate, it lends itself to educational physics experiments and analogies. Precession and nutation are visualized by reflecting the beam from a laser pointer off the ‘spignet’. Precession is fundamental to nuclear magnetic resonance, magnetic resonance imaging, particle traps and the movement of bodies in space. Longitudinal and lateral bounce behaviour is explained via ‘the principle of gentle superposition’ of two traps: the micro-precessional and the macro-trap. Theory is initiated. Scaling experiments are mentioned. Industrial applications might follow. Patent pending.

  17. Impulse absorption by horizontal magnetic granular chain

    Directory of Open Access Journals (Sweden)

    Dingxin Leng

    2016-02-01

    Full Text Available The granular medium is known as a protecting material for shock mitigation. We study the impulse absorption of an alignment of magnetic spheres placed horizontally under a non-uniform magnetic field. The phenomenon of the wave dispersion is presented. This system can absorb 85% ∼ 95% (88% ∼ 98% of the incident peak force (energy under the applied magnetic field strength in 0.1 T ∼ 1.0 T. The shock attenuation capacities are enhanced by the increment of field strength. With an intelligent control system, it is conceivable that the magnetic granular chain may offer possibilities in developing adaptive shock protectors.

  18. Applying GPS to check horizontal control quality

    OpenAIRE

    Jakub Vincent; Weiss Gabriel; Sabová Jana

    2004-01-01

    GPS technologies can also be used for check quality in available horizontal point set with coordinates CJ of the frame S-JTSK. When survey and setting-out tasks should be performed in certain area, one can found in it allways some points of the fundamental and detail state controls. To use these points for some actual aims, it is necessary to investigate their compatibility (among the point mark positions and the point coordinate of control points). This can be done using GPS surveying that m...

  19. Gilberto Freyre e o horizonte do modernismo

    Directory of Open Access Journals (Sweden)

    Mariza Veloso

    2000-12-01

    Full Text Available O artigo discute a inserção de Gilberto Freyre no horizonte do modernismo brasileiro e constrói seu argumento a partir dos ideais que o intelectual compartilha com sua geração. As principais linhas de interpretação responsáveis pela renovação do pensamento brasileiro podem ser sumarizadas pela substituição do conceito de Raça pelo de Cultura e pela alteração que provoca nos conceitos de História, Memória, Tempo e Tradição.

  20. Medial branch neurotomy in low back pain

    International Nuclear Information System (INIS)

    This study aimed to assess the effectiveness of pulsed radiofrequency medial branch dorsal ramus neurotomy in patients with facet joint syndrome. From January 2008 to April 2010, 92 patients with facet joint syndrome diagnosed by strict inclusion criteria and controlled diagnostic blocks undergone medial branch neurotomy. We did not exclude patients with failed back surgery syndrome (FBSS). Electrodes (20G) with 5-mm active tip were placed under fluoroscopy guide parallel to medial branch. Patients were followed up by physical examination and by Visual Analog Scale and Oswestry Disability Index at 1, 6, and 12 months. In all cases, pain improvement was statistically significant and so quality of life. Three non-FBSS patients had to undergo a second neurotomy because of non-satisfactory pain decrease. Complications were reported in no case. Medial branch radiofrequency neurotomy has confirmed its well-established effectiveness in pain and quality of life improvement as long as strict inclusion criteria be fulfilled and nerve ablation be accomplished by parallel electrode positioning. This statement can be extended also to FBSS patients. (orig.)

  1. Medial branch neurotomy in low back pain

    Energy Technology Data Exchange (ETDEWEB)

    Masala, Salvatore; Mammucari, Matteo; Simonetti, Giovanni [Interventional Radiology and Radiotherapy University ' ' Tor Vergata' ' , Department of Diagnostic and Molecular Imaging, Rome (Italy); Nano, Giovanni [Interventional Radiology and Radiotherapy University ' ' Tor Vergata' ' , Department of Diagnostic and Molecular Imaging, Rome (Italy); University ' ' Tor Vergata' ' , Department of Radiology, Rome (Italy); Marcia, Stefano [S. Giovanni di Dio Hospital, Department of Diagnostic and Molecular Imaging, Cagliari (Italy)

    2012-07-15

    This study aimed to assess the effectiveness of pulsed radiofrequency medial branch dorsal ramus neurotomy in patients with facet joint syndrome. From January 2008 to April 2010, 92 patients with facet joint syndrome diagnosed by strict inclusion criteria and controlled diagnostic blocks undergone medial branch neurotomy. We did not exclude patients with failed back surgery syndrome (FBSS). Electrodes (20G) with 5-mm active tip were placed under fluoroscopy guide parallel to medial branch. Patients were followed up by physical examination and by Visual Analog Scale and Oswestry Disability Index at 1, 6, and 12 months. In all cases, pain improvement was statistically significant and so quality of life. Three non-FBSS patients had to undergo a second neurotomy because of non-satisfactory pain decrease. Complications were reported in no case. Medial branch radiofrequency neurotomy has confirmed its well-established effectiveness in pain and quality of life improvement as long as strict inclusion criteria be fulfilled and nerve ablation be accomplished by parallel electrode positioning. This statement can be extended also to FBSS patients. (orig.)

  2. Measurement of the eta decay branching ratio

    CERN Document Server

    Bargholtz, C; Bogoslawsky, D; Calén, H; Capellaro, F; Clement, H; Demirörs, L; Ekström, C; Fransson, K; Geren, L; Gustafsson, L; Höistad, Bo; Ivanov, G; Jacewicz, M; Jiganov, E; Johansson, T; Keleta, S; Koch, I; Kullander, Sven; Kupsc, A; Kuznetsov, A; Laukhin, I V; Lindberg, K; Marciniewski, P; Meier, R; Morosov, B; Oelert, W; Pauly, C; Pettersson, H; Petukhov, Yu P; Povtorejko, A; Ruber, Roger J M Y; Schönning, K; Scobel, W; Shafigullin, R; Shwartz, B; Skorodko, T Yu; Sopov, V; Stepaniak, J; Chernyshov, V; Tegnér, P E; Engblom, P T; Tikhomirov, V; Turowiecki, A; Wagner, G J; Wolke, M; Yamamoto, A; Zabierowski, J; Zartova, I; Zlomanczuk, Yu; Bargholtz, Chr.

    2007-01-01

    The reaction pd->3He eta at threshold was used to provide a clean source of eta mesons for decay studies with the WASA detector at CELSIUS. The branching ratio of the decay eta->pi+pi-e+e- is measured to be (4.6+/-1.4+/-0.5)x10^-4.

  3. 76 FR 60757 - Executive Branch Qualified Trusts

    Science.gov (United States)

    2011-09-30

    ... qualified trusts provisions for the executive branch in subparts D and E of 5 CFR part 2634 (see 57 FR 11800.... 12674, 54 FR 15159, 3 CFR, 1989 Comp., p. 215, as modified by E.O. 12731, 55 FR 42547, 3 CFR, 1990 Comp... been in business, its policies and philosophy in managing assets, the types of clients it serves,...

  4. Infrared studies of asymptotic giant branch stars

    International Nuclear Information System (INIS)

    In this thesis studies are presented of asymptotic giant branch stars, which are thought to be an important link in the evolution of the galaxy. The studies were performed on the basis of data collected by the IRAS, the infrared astronomical satelite. 233 refs.; 33 figs.; 16 tabs

  5. The AFCRL Lunar amd Planetary Research Branch

    Science.gov (United States)

    Price, Stephan D.

    2011-07-01

    The Lunar and Planetary research program led by Dr John (Jack) Salisbury in the 1960s at the United States Air Force Cambridge Research Laboratories (AFCRL) investigated the surface characteristics of Solar System bodies. The Branch was one of the first groups to measure the infrared spectra of likely surface materials in the laboratory under appropriate vacuum and temperature conditions. The spectral atlases created from the results were then compared to photometric and spectral measurements obtained from ground- and balloon-based telescopes to infer the mineral compositions and physical conditions of the regoliths of the Moon, Mars and asteroids. Starting from scratch, the Branch initially sponsored observations of other groups while its in-house facilities were being constructed. The earliest contracted efforts include the spatially-resolved mapping of the Moon in the first half of the 1960s by Richard W. Shorthill and John W. Saari of the Boeing Scientific Research Laboratories in Seattle. This effort ultimately produced isophotal and isothermal contour maps of the Moon during a lunation and time-resolved thermal images of the eclipsed Moon. The Branch also sponsored probe rocket-based experiments flown by Riccardo Giacconi and his group at American Science and Engineering Inc. that produced the first observations of X-ray stars in 1962 and later the first interferometric measurement of the ozone and C02 emission in the upper atmosphere. The Branch also made early use of balloon-based measurements. This was a singular set of experiments, as these observations are among the very few mid-infrared astronomical measurements obtained from a balloon platform. Notable results of the AFCRL balloon flights were the mid-infrared spectra of the spatially-resolved Moon obtained with the University of Denver mid-infrared spectrometer on the Branch's balloon-borne 61-cm telescope during a 1968 flight. These observations remain among the best available. Salisbury also funded

  6. Applications of horizontal drilling technology in Saudi oil fields

    International Nuclear Information System (INIS)

    The technology of drilling and production of horizontal wells is probably one of the most significant breakthrough in the oil and gas industry of the eighties. The continuous improvement of hardware equipment made horizontal drilling cost-effective technique for developing reserves, improving productivity and recovery in oil and gas reservoir. This paper is devoted to Saudi experience in horizontal drilling. The last years have been an exciting period for those who believed in horizontal drilling applicability in Saudi Arabia. At the end of the year 1997 more than 150 horizontal wells have been drilled in Saudi oil fields. There are four major horizontal well applications identified in Saudi Arabia oil fields; 1) Control of coning in relatively thin remaining all column area, 2) Improving sweep efficiency of water flooding program. 3) Improving productivity rate in thin/tight reservoirs and 4) Saving in total development costs in conjunction with previous three applications. This paper presents the major areas of application of horizontal well and more specifically the objectives of applying horizontal drilling in different Saudi oil fields and the world horizontal drilling activities along with the Saudi experience will be convered. This paper surveys different field examples to show the application trends of horizontal well technology in both offshore and onshore oil fields. The main objective of this survey is to demonstrate the performance improvement of these oil fields after the application of horizontal well technology. (author)

  7. Large-Actuator-Number Horizontal Path Correction of Atmospheric Turbulence utilizing an Interferometric Phase Conjugate Engine

    International Nuclear Information System (INIS)

    An adaptive optical system used to correct horizontal beam propagation paths has been demonstrated. This system utilizes an interferometric wave-front sensor and a large-actuator-number MEMS-based spatial light modulator to correct the aberrations incurred by the beam after propagation along the path. Horizontal path correction presents a severe challenge to adaptive optics systems due to the short atmospheric transverse coherence length and the high degree of scintillation incurred by laser propagation along these paths. Unlike wave-front sensors that detect phase gradients, however, the interferometric wave-front sensor measures the wrapped phase directly. Because the system operates with nearly monochromatic light and uses a segmented spatial light modulator, it does not require that the phase be unwrapped to provide a correction and it also does not require a global reconstruction of the wave-front to determine the phase as required by gradient detecting wave-front sensors. As a result, issues with branch points are eliminated. Because the atmospheric probe beam is mixed with a large amplitude reference beam, it can be made to operate in a photon noise limited regime making its performance relatively unaffected by scintillation. The MEMS-based spatial light modulator in the system contains 1024 pixels and is controlled to speeds in excess of 800 Hz, enabling its use for correction of horizontal path beam propagation. In this article results are shown of both atmospheric characterization with the system and open loop horizontal path correction of a 1.53 micron laser by the system. To date Strehl ratios of greater than 0.5 have been achieved

  8. In-situ bioremediation via horizontal wells

    International Nuclear Information System (INIS)

    This project is designed to demonstrate in situ bioremediation of groundwater and sediment contaminated with chlorinated solvents. Indigenous microorganisms were stimulated to degrade TCE, PCE and their daughter products in situ by addition of nutrients to the contaminated zone. In situ biodegradation is a highly attractive technology for remediation because contaminants are destroyed, not simply moved to another location or immobilized, thus decreasing costs, risks, and time, while increasing efficiency and public and regulatory acceptability. Bioremediation has been found to be among the least costly technologies in applications where it will work (Radian 1989). Subsurface soils and water adjacent to an abandoned process sewer line at the SRS have been found to have elevated levels of TCE (Marine and Bledsoe 1984). This area of subsurface and groundwater contamination is the focus of a current integrated demonstration of new remediation technologies utilizing horizontal wells. Bioremediation has the potential to enhance the performance of in situ air stripping as well as offering stand-alone remediation of this and other contaminated sites (Looney et al. 1991). Horizontal wells could also be used to enhance the recovery of groundwater contaminants for bioreactor conversions from deep or inaccessible areas (e.g., under buildings) and to enhance the distribution of nutrient or microbe additions in an in situ bioremediation

  9. Pattern selection in a horizontally vibrated container

    International Nuclear Information System (INIS)

    We present results of an experimental and numerical investigation of the patterns realized by surface waves within an open rectangular container subjected to horizontal vibrations at frequencies of 40–100 Hz. The first instability exhibited by the primary harmonic wave field is subharmonic, and may be identified with the cross-wave instability often seen in wave tank experiments. We show that, contrary to common theoretical and experimental assumptions, and despite their name, these subharmonic waves are not oriented crosswise, but at an intermediate angle with respect to the axis of vibration. Hence, the pattern selection problem for horizontally forced Faraday waves is more complex than has previously been assumed. We establish the robustness of this obliquely oriented surface wave pattern by varying the forcing frequency and amplitude, the fluid viscosity, the fluid depth, and the boundary conditions. Previous work on cross-waves is reviewed and discussed in relation to the current results. Finally, numerical simulations using a reduced model with an appropriate forcing term are used to support the generality of the experimental observations. (paper)

  10. Pattern selection in a horizontally vibrated container

    Energy Technology Data Exchange (ETDEWEB)

    Porter, J; Tinao, I; Laveron-Simavilla, A; Lopez, C A, E-mail: jeff.porter@upm.es [E.T.S.I. Aeronauticos, Universidad Politecnica de Madrid, Plaza Cardenal Cisneros 3, 28040 Madrid (Spain)

    2012-10-15

    We present results of an experimental and numerical investigation of the patterns realized by surface waves within an open rectangular container subjected to horizontal vibrations at frequencies of 40-100 Hz. The first instability exhibited by the primary harmonic wave field is subharmonic, and may be identified with the cross-wave instability often seen in wave tank experiments. We show that, contrary to common theoretical and experimental assumptions, and despite their name, these subharmonic waves are not oriented crosswise, but at an intermediate angle with respect to the axis of vibration. Hence, the pattern selection problem for horizontally forced Faraday waves is more complex than has previously been assumed. We establish the robustness of this obliquely oriented surface wave pattern by varying the forcing frequency and amplitude, the fluid viscosity, the fluid depth, and the boundary conditions. Previous work on cross-waves is reviewed and discussed in relation to the current results. Finally, numerical simulations using a reduced model with an appropriate forcing term are used to support the generality of the experimental observations. (paper)

  11. Vegetation survey of Pen Branch and Four Mile Creek wetlands

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    One hundred-fifty plots were recently sampled (vegetational sampling study) at the Savannah River Site (SRS). An extensive characterization of the vascular flora, in four predetermined strata (overstory, Understory, shrub layer, and ground cover), was undertaken to determine dominance, co-dominance, and the importance value (I.V.) of each species. These results will be used by the Savannah River Laboratory (SRL) to evaluate the environmental status of Four Mile Creek, Pen Branch, and two upland pine stands. Objectives of this study were to: Describe in detail the plant communities previously mapped with reference to the topography and drainage, including species of plants present: Examine the successional trends within each sampling area and describe the extent to which current vegetation communities have resulted from specific earlier vegetation disturbances (e.g., logging and grazing); describe in detail the botanical field techniques used to sample the flora; describe the habitat and location of protected and/or rare species of plants; and collect and prepare plant species as herbarium quality specimens. Sampling was conducted at Four Mile Creek and Pen Branch, and in two upland pine plantations of different age growth.

  12. Vegetation survey of Pen Branch and Four Mile Creek wetlands

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    One hundred-fifty plots were recently sampled (vegetational sampling study) at the Savannah River Site (SRS). An extensive characterization of the vascular flora, in four predetermined strata (overstory, Understory, shrub layer, and ground cover), was undertaken to determine dominance, co-dominance, and the importance value (I.V.) of each species. These results will be used by the Savannah River Laboratory (SRL) to evaluate the environmental status of Four Mile Creek, Pen Branch, and two upland pine stands. Objectives of this study were to: Describe in detail the plant communities previously mapped with reference to the topography and drainage, including species of plants present: Examine the successional trends within each sampling area and describe the extent to which current vegetation communities have resulted from specific earlier vegetation disturbances (e.g., logging and grazing); describe in detail the botanical field techniques used to sample the flora; describe the habitat and location of protected and/or rare species of plants; and collect and prepare plant species as herbarium quality specimens. Sampling was conducted at Four Mile Creek and Pen Branch, and in two upland pine plantations of different age growth.

  13. Pipeline corridors through wetlands - impacts on plant communities: Deep Creek and Brandy Branch crossings, Nassau County, Florida

    Energy Technology Data Exchange (ETDEWEB)

    Shem, L.M.; Van Dyke, G.D.; Zimmerman, R.E.

    1994-12-01

    The goal of the Gas Research Institute Wetland Corridors Program is to document impacts of existing pipelines on the wetlands they traverse. To accomplish this goal, 12 existing wetland crossings were surveyed. These sites varied in elapsed time since pipeline construction, wetland type, pipeline installation techniques, and right-of-way (ROW) management practices. This report presents the results of surveys conducted July 14-18, 1992, at the Deep Creek and the Brandy Branch crossings of a pipeline installed during May 1991 in Nassau County, Florida. Both floodplains supported bottomland hardwood forests. The pipeline at the Deep Creek crossing was installed by means of horizontal directional drilling after the ROW had been clear-cut, while the pipeline at the Brandy Branch crossing was installed by means of conventional open trenching. Neither site was seeded or fertilized. At the time of sampling, a dense vegetative community, made up primarily of native perennial herbaceous species, occupied the ROW within the Deep Creek floodplain. The Brandy Branch ROW was vegetated by a less dense stand of primarily native perennial herbaceous plants. Plant diversity was also lower at the Brandy Branch crossing than at the Deep Creek crossing. The results suggest that some of the differences in plant communities are related to the more hydric conditions at the Brandy Branch floodplain.

  14. NUMERICAL DETERMINATION OF HORIZONTAL SETTLERS PERFORMANCE

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2015-08-01

    Full Text Available Purpose.Horizontal settlers are one of the most important elements in the technological scheme of water purification. Their use is associated with the possibility to pass a sufficiently large volume of water. The important task at the stage of their designing is evaluating of their effectiveness. Calculation of the efficiency of the settler can be made by mathematical modeling. Empirical, analytical models and techniques that are currently used to solve the problem, do not allow to take into account the shape of the sump and various design features that significantly affects the loyalty to a decision on the choice of the size of the settling tank and its design features. The use of analytical models is limited only to one-dimensional solutions, does not allow accounting for nonuniform velocity field of the flow in the settler. The use of advanced turbulence models for the calculation of the hydrodynamics in the settler complex forms now requires very powerful computers. In addition, the calculation of one variant of the settler may last for dozens of hours. The aim of the paper is to build a numerical model to evaluate the effectiveness of horizontal settling tank modified design. Methodology. Numerical models are based on: 1 equation of potential flow; 2 equation of inviscid fluid vortex flow; 3 equation of viscous fluid dynamics; 4 mass transfer equation. For numerical simulation the finite difference schemes are used. The numerical calculation is carried out on a rectangular grid. For the formation of the computational domain markers are used. Findings.The models allow calculating the clarification process in the settler with different form and different configuration of baffles. Originality. A new approach to investigate the mass transfer process in horizontal settler was proposed. This approach is based on the developed CFD models. Three fluid dynamics models were used for the numerical investigation of flows and waste waters purification

  15. Modeling of Two-Phase Flow through a Rotating Tube with Twin Exit Branches

    Directory of Open Access Journals (Sweden)

    Sun-Wen Cheng

    2000-01-01

    Full Text Available A numerical model is proposed to determine the dynamic behavior of single-phase and twophase, two-component flows through a horizontal rotating tube with identical twin exit branches. The working fluid, oil, enters the tube through a radial duct attached at one end and exits into open air through the twin radial branches, one located at midway and the other at the end of the tube. The branch-to-tube diameter ratio, rotational speed, and total oil flow rate are varied. It is experimentally revealed in previous study that the air cavitation occurs at lower speeds, leading to a two-phase flow with the air-oil ratio (void fraction varying with the rotating speed. A unique characteristic in two-phase flow, i.e., hysteresis, is found to exist in both oil flow rates and inlet pressure. In theoretical modeling, the governing flow equations are incorporated by empirical equations for hydraulic head losses. The predicted and measured exit oil flow rates are compared with good agreement in both the single-phase and annular flow regimes. Only qualitative agreement is achieved in the bubbly and bubbly-slug flow regimes. The model can be applied to improve the design and thus enhance the performance of automatic transmission lines, and the cooling efficiency of rotating machines and petroleum drilling process.

  16. Prevalence of Rheumatic Heart Disease in a Public School of Belo Horizonte

    OpenAIRE

    Lavinia Pimentel Miranda; Paulo Augusto Moreira Camargos; Rosália Morais Torres; Zilda Maria Alves Meira

    2014-01-01

    Background: Previous studies indicate that compared with physical examination, Doppler echocardiography identifies a larger number of cases of rheumatic heart disease in apparently healthy individuals. Objectives: To determine the prevalence of rheumatic heart disease among students in a public school of Belo Horizonte by clinical evaluation and Doppler echocardiography. Methods: This was a cross-sectional study conducted with 267 randomly selected school students aged between 6 and ...

  17. The effect of horizontal versus vertical task presentation on children's performance in coordinate tasks

    OpenAIRE

    Worsfold, N; Davis, A.; De Bruyn, B

    2008-01-01

    Empirical work on children’s ability to understand spatial coordinates has focused on the factors that increase children’s proficiency. When interpreting performance, it should be considered that presenting a coordinate task on a horizontal surface might constrain the responses that children make because some target positions are further away from the child than others. Vertical task presentation removes this constraint. Children aged 3 to 9 years were presented with an interpretative coordin...

  18. Modelling the horizontal steam generator with APROS

    International Nuclear Information System (INIS)

    In this paper the capability of the five- and six-equation models of the simulation code APROS to simulate the behaviour of the horizontal steam generator is discussed. Different nodalizations are used in the modelling and the results of the stationary state runs are compared. Exactly the same nodalizations have been created for the five- and six-equation models. The main simulation results studied in this paper are void fraction and mass flow distributions in the secondary side of the steam generator. It was found that quite a large number of simulation volumes is required to simulate the distributions with a reasonable accuracy. The simulation results of the different models are presented and their validity is discussed. (orig.)

  19. Horizontal Drop of 21- PWR Waste Package

    International Nuclear Information System (INIS)

    The objective of this calculation is to determine the structural response of the waste package (WP) dropped horizontally from a specified height. The WP used for that purpose is the 21-Pressurized Water Reactor (PWR) WP. The scope of this document is limited to reporting the calculation results in-terms of stress intensities. This calculation is associated with the WP design and was performed by the Waste Package Design group in accordance with the ''Technical Work Plan for: Waste Package Design Description for LA'' (Ref. 16). AP-3.12Q, ''Calculations'' (Ref. 1 1) is used to perform the calculation and develop the document. The sketches attached to this calculation provide the potential dimensions and materials for the 21-PWR WP design

  20. Numerical Investigation on Submerged Horizontal Plate

    Institute of Scientific and Technical Information of China (English)

    康海贵; 王科

    2001-01-01

    Hydrodynamic characters on a horizontal, thin, rigid plate located beneath the free surface are numerically investigated. Assuming a linear, time-harmonic potential flow and utilizing Green identity, the governing Laplace equation can be simplified into Fredholm integral equation ofthe second kind. Supposing linear-order discontinuous elements along intersecting vertical boundaries, and by use of the boundary element method, numerical solution about source strength distribution on the plate can be changed into a series of algebraic equations. The 3D Green function is introduced to set up the integral equations, and the GMRES solver is performed for solving the large dense linear system of equations. The added-mass, damping force and exciting force are evaluated directly from the equations. It is found that the added-mass coefficient becomes negative for a range of frequencies when the plate is sufficiently close to the free surface.

  1. The intrinsic depth of horizontal convection

    Science.gov (United States)

    Chen, Chen; Wang, Wei; Wu, Dexing

    2010-05-01

    The mainstream depth of a return flow can be viewed as an intrinsic depth of horizontal convection. By using a theoretical tube model combined with the application of the Maximum Entropy Production Principle (MaxEPP) in thermodynamics, the following statements can be made. Under fixed external forcing, the system chooses a particular depth as the mainstream depth of its return flow, the depth of which not only satisfies the maximum circulation rate and the maximum heat transport, but also satisfies the maximum entropy production rate. A comparison between this intrinsic depth and the container height leads to the definition of a relative partial and full-penetration pattern of the circulation. Moreover, this intrinsic depth is found to vary with the external forcing; the regulation of this variation is related to the Modified Rayleigh number.

  2. Horizontal gene exchange in environmental microbiota

    Directory of Open Access Journals (Sweden)

    Rustam I Aminov

    2011-07-01

    Full Text Available Horizontal gene transfer (HGT plays an important role in the evolution of life on the Earth. This view is supported by numerous occasions of HGT that are recorded in the genomes of all three domains of living organisms. HGT-mediated rapid evolution is especially noticeable among the Bacteria, which demonstrate formidable adaptability in the face of recent environmental changes imposed by human activities, such as the use of antibiotics, industrial contamination, and intensive agriculture. At the heart of the HGT-driven bacterial evolution and adaptation are highly sophisticated natural genetic engineering tools in the form of a variety of mobile genetic elements (MGEs. The main aim of this review is to give a brief account of the occurrence and diversity of MGEs in natural ecosystems and of the environmental factors that may affect MGE-mediated HGT.

  3. Horizontal beam tubes in FRM-II

    International Nuclear Information System (INIS)

    The new research reactor in Garching FRM-II is equipped with 10 leak tight horizontal beam tubes (BT1 - BT10), each of them consisting of a beam tube structure taking an insert with neutron channels. The design of all beam tube structures is similar whereas the inserts are adapted to the special requirements of the using of each beam tube. Inside the reflector tank the beam tube structures are shaped by the inner cones which are made of Al-alloy with circular and rectangular cross sections. They are located in the region of maximum neutron flux (exception BT10), they are directly connected to the flanges of the reflector tank, their lengths are about 1.5 m (exception BT10) and their axes are directed tagentially to the core centre thus contributing to a low γ-noise at the experiments. (orig.)

  4. Mixed convection flow past a horizontal plate

    Directory of Open Access Journals (Sweden)

    Savić Lj.

    2005-01-01

    Full Text Available The mixed convection flow past a horizontal plate being aligned through a small angle of attack to a uniform free stream will be considered in the limit of large Reynolds number and small Richardson number. Even a small angle of inclination of the wake is sufficient for the buoyancy force to accelerate the flow in the wake which causes a velocity overshoot in the wake. Moreover a hydrostatic pressure difference across the wake induces a correction to the potential flow which influences the inclination of the wake. Thus the wake and the correction of the potential flow have to be determined simultaneously. However, it turns out that solutions exist only if the angle of attack is sufficiently large. Solutions are computed numerically and the influence of the buoyancy on the lift coefficient is determined.

  5. Modelling the horizontal steam generator with APROS

    Energy Technology Data Exchange (ETDEWEB)

    Ylijoki, J. [VTT Energy, Espoo (Finland); Palsinajaervi, C.; Porkholm, K. [IVO International Ltd, Vantaa (Finland)

    1995-12-31

    In this paper the capability of the five- and six-equation models of the simulation code APROS to simulate the behaviour of the horizontal steam generator is discussed. Different nodalizations are used in the modelling and the results of the stationary state runs are compared. Exactly the same nodalizations have been created for the five- and six-equation models. The main simulation results studied in this paper are void fraction and mass flow distributions in the secondary side of the steam generator. It was found that quite a large number of simulation volumes is required to simulate the distributions with a reasonable accuracy. The simulation results of the different models are presented and their validity is discussed. (orig.). 4 refs.

  6. Horizontal Hostility among Non-Meat Eaters

    Science.gov (United States)

    Rothgerber, Hank

    2014-01-01

    The present study examined intergroup judgments made between four groups of non-meat eaters: health vegetarians; ethical vegetarians; health vegans, and ethical vegans. Consistent with hypotheses based on horizontal hostility and the need to maintain ingroup distinctiveness, ethical vegetarians gave unfavorable evaluations to health vegetarians relative to vegans, especially when the mainstream omnivore group was made salient. Contrary to expectations, vegans gave relatively more favorable evaluations to ethical vegetarians than health vegetarians when mainstream salience was low. This was especially true for vegans who were motivated primarily by ethical concerns. When mainstream salience was high, vegans did not distinguish between the vegetarian subgroups. Results suggest that one’s motives for abstaining from meat often play a larger role in this type of intergroup perceptions than one’s dietary practices. PMID:24809342

  7. Horizontal Drop of 21- PWR Waste Package

    International Nuclear Information System (INIS)

    The objective of this calculation is to determine the structural response of the waste package (WP) dropped horizontally from a specified height. The WP used for that purpose is the 21-Pressurized Water Reactor (PWR) WP. The scope of this document is limited to reporting the calculation results in terms of stress intensities. The information provided by the sketches (Attachment I) is that of the potential design of the type of WP considered in this calculation, and all obtained results are valid for that design only. This calculation is associated with the WP design and was performed by the Waste Package Design group in accordance with the ''Technical Work Plan for: Waste Package Design Description for LA'' (Ref. 16). AP-3.12Q, ''Calculations'' (Ref. 11) is used to perform the calculation and develop the document. The sketches attached to this calculation provide the potential dimensions and materials for the 21-PWR WP design

  8. Horizon-T Experiment Calibrations - Cables

    CERN Document Server

    Beznosko, D; Iakovlev, A; Makhataeva, Z; Vildanova, M I; Yelshibekov, K; Zhukov, V V

    2016-01-01

    An innovative detector system called Horizon-T is constructed to study Extensive Air Showers (EAS) in the energy range above 1016 eV coming from a wide range of zenith angles (0o - 85o). The system is located at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level. The detector consists of eight charged particle detection points separated by the distance up to one kilometer as well as optical detector to view the Vavilov-\\v{C}erenkov light from the EAS. Each detector connects to the Data Acquisition system via cables. The calibration of the time delay for each cable and the signal attenuation is provided in this article.

  9. Conjugate natural convection between horizontal eccentric cylinders

    Science.gov (United States)

    Nasiri, Davood; Dehghan, Ali Akbar; Hadian, Mohammad Reza

    2016-06-01

    This study involved the numerical investigation of conjugate natural convection between two horizontal eccentric cylinders. Both cylinders were considered to be isothermal with only the inner cylinder having a finite wall thickness. The momentum and energy equations were discretized using finite volume method and solved by employing SIMPLER algorithm. Numerical results were presented for various solid-fluid conductivity ratios (KR) and various values of eccentricities in different thickness of inner cylinder wall and also for different angular positions of inner cylinder. From the results, it was observed that in an eccentric case, and for KR 10 value caused an increase in overline{{K_{eq} }} . It was also concluded that in any angular position of inner cylinder, the value of overline{{K_{eq} }} increased with increase in the eccentricity.

  10. Photovoltaic Program Branch annual report, FY 1989

    Energy Technology Data Exchange (ETDEWEB)

    Summers, K A [ed.

    1990-03-01

    This report summarizes the progress of the Photovoltaic (PV) Program Branch of the Solar Energy Research Institute (SERI) from October 1, 1988, through September 30, 1989. The branch is responsible for managing the subcontracted portion of SERI's PV Advanced Research and Development Project. In fiscal year (FY) 1989, this included nearly 50 subcontracts, with a total annualized funding of approximately $13.1 million. Approximately two-thirds of the subcontracts were with universities, at a total funding of nearly $4 million. The six technical sections of the report cover the main areas of the subcontracted program: Amorphous Silicon Research, Polycrystalline Thin Films, Crystalline Silicon Materials Research, High-Efficiency Concepts, New Ideas, and University Participation. Technical summaries of each of the subcontracted programs provide a discussion of approaches, major accomplishments in FY 1989, and future research directions. Each report will be cataloged individually.

  11. The Higgs Branch of Impurity Theories

    CERN Document Server

    Kapustin, A A; Kapustin, Anton; Sethi, Savdeep

    1998-01-01

    We consider supersymmetric gauge theories with impurities in various dimensions. These systems arise in the study of intersecting branes. Unlike conventional gauge theories, the Higgs branch of an impurity theory can have compact directions. For models with eight supercharges, the Higgs branch is a hyperKahler manifold given by the moduli space of solutions of certain differential equations. These equations are the dimensional reductions of self-duality equations with boundary conditions determined by the impurities. They can also be interpreted as Nahm transforms of self-duality equations on toroidally compactified spaces. We discuss the application of our results to the light-cone formulation of Yang-Mills theories and to the solution of certain N=2 d=4 gauge theories.

  12. Branch management into micropipeline joint dot

    Directory of Open Access Journals (Sweden)

    Dimitar Tyanev

    2011-11-01

    Full Text Available This paper considers problems related to hardware implementation of computational process with conditional jumps. Hardware refers to asynchronous pipeline organization at microoperational level. Exploration is dedicated to one of the tasks presented in (Tyanev, D., 2009 concerning to micropipeline controller design to control micropipeline stage into joint dot of branch algorithm. Joint dot is the point at which few preceding branches are combined. It appears inevitably into conditional jump structures and this is the reason for the actuality of its problem. Analysis of this new task is presented and request arbitration functioning principles are formulated for the incoming to joint dot requests. The arbiter is responsible for the fair choice on which depends steady peformance of separate pipeline brances. Paper also describes pipeline controller synthesis and analysis of its operation in two variants: about 2-phase and 4-phase data transfer protocol. The synthesized asynchronous arbiter scheme is invariant to the type of pipeline protocol.

  13. Branching Dynamics of Viral Information Spreading

    CERN Document Server

    Iribarren, José Luis

    2011-01-01

    Despite its importance for rumors or innovations propagation, peer-to-peer collaboration, social networking or Marketing, the dynamics of information spreading is not well understood. Since the diffusion depends on the heterogeneous patterns of human behavior and is driven by the participants' decisions, its propagation dynamics shows surprising properties not explained by traditional epidemic or contagion models. Here we present a detailed analysis of our study of real Viral Marketing campaigns where tracking the propagation of a controlled message allowed us to analyze the structure and dynamics of a diffusion graph involving over 31,000 individuals. We found that information spreading displays a non-Markovian branching dynamics that can be modeled by a two-step Bellman-Harris Branching Process that generalizes the static models known in the literature and incorporates the high variability of human behavior. It explains accurately all the features of information propagation under the "tipping-point" and can...

  14. In situ bioremediation via horizontal wells

    International Nuclear Information System (INIS)

    The test consisted of methane mixed with air into the contaminated aquifer via a horizontal well and extraction from the vadose zone via a parallel horizontal well. This configuration has the advantage of simultaneously stimulating methanotrophic activity in both the groundwater and vadose zone, and inhibiting spread of the contaminant plume. Groundwater was monitored biweekly from 13 wells for a variety of chemical and microbiological parameters. Groundwater from wells in affected areas showed increases in methanotrophs of more than 1 order of magnitude every 2 weeks for several weeks after 1% methane-in-air injection was started. Some wells had increases as much as 7 orders of magnitude. Simultaneous with the increase in methanotrophs was a decrease in water and soil gas concentrations of trichloroethylene (TCE) and tetrachloroethane (PCE). Two wells declined in TCE/PCE concentration in the water by more than 90% to below 2 ppb. All of the wells in the affected zone showed significant decreases in contaminants in less than one month. Chloride concentrations in the water were inversely correlated with TCE/PCE concentration. Four of five vadose zone piezometers declined from concentration as high as 10,000 ppm to less than 5 ppm in less than 6 weeks. The fifth cluster also declined by more than 95%. After only three months on injection, a decline in TCE/PCE in the sediment of more than 30% was also observed, with TCE/PCE being undetectable in most sediments at the end of the 14-month test. Gene probes and direct isolation from the water and sediment revealed that the right types of methanotrophs were being stimulated and that isolates could degrade TCE at a high rate

  15. Horizontal transfer of supernumerary chromosomes in fungi.

    Science.gov (United States)

    van der Does, H Charlotte; Rep, Martijn

    2012-01-01

    Several species of filamentous fungi contain so-called dispensable or supernumerary chromosomes. These chromosomes are dispensable for the fungus to survive, but may carry genes required for specialized functions, such as infection of a host plant. It has been shown that at least some dispensable chromosomes are able to transfer horizontally (i.e., in the absence of a sexual cycle) from one fungal strain to another. In this paper, we describe a method by which this can be shown. Horizontal chromosome transfer (HCT) occurs during co-incubation of two strains. To document the actual occurrence of HCT, it is necessary to select for HCT progeny. This is accomplished by transforming two different drug-resistance genes into the two parent strains before their co-incubation. In one of the strains (the "donor"), a drug-resistance gene should be integrated in a chromosome of which the propensity for HCT is under investigation. In the "tester" or "recipient" strain, another drug-resistance gene should be integrated somewhere in the core genome. In this way, after co-incubation, HCT progeny can be selected on plates containing both drugs. HCT can be initiated with equal amounts of asexual spores of both strains, plated on regular growth medium for the particular fungus, followed by incubation until new asexual spores are formed. The new asexual spores are then harvested and plated on plates containing both drugs. Double drug-resistant colonies that appear should carry at least one chromosome from each parental strain. Finally, double drug-resistant strains need to be analysed to assess whether HCT has actually occurred. This can be done by various genome mapping methods, like CHEF-gels, AFLP, RFLP, PCR markers, optical maps, or even complete genome sequencing. PMID:22183669

  16. Minimum disparity estimation in controlled branching processes

    OpenAIRE

    Gonzalez, Miguel; Minuesa, Carmen; del Puerto, Ines

    2015-01-01

    Minimum disparity estimation in controlled branching processes is dealt with by assuming that the offspring law belongs to a general parametric family. Under some regularity conditions it is proved that the minimum disparity estimators proposed -based on the nonparametric maximum likelihood estimator of the offspring law when the entire family tree is observed- are consistent and asymptotic normally distributed. Moreover, it is discussed the robustness of the estimators proposed. Through a si...

  17. Modelling an observer's branch of extremal consciousness

    OpenAIRE

    Polley, L.

    2012-01-01

    Extreme-order statistics is applied to the branches of an observer in a many-worlds framework. A unitary evolution operator for a step of time is constructed, generating pseudostochastic behaviour with a power-law distribution when applied repeatedly to a particular initial state. The operator models the generation of records, their dating, the splitting of the wavefunction at quantum events, and the recalling of records by the observer. Due to the huge ensemble near an observer's end, the br...

  18. New branching rules induced by plethysm

    International Nuclear Information System (INIS)

    We derive group branching laws for formal characters of subgroups Hπ of GL(n) leaving invariant an arbitrary tensor Tπ of Young symmetry type π where π is an integer partition. The branchings GL(n) ↓ GL(n-1), GL(n) ↓ O(n) and GL(2n) ↓ Sp(2n) fixing a vector vi, a symmetric tensor gij = gji and an antisymmetric tensor fij = -fji, respectively, are obtained as special cases. All new branchings are governed by Schur function series obtained from plethysms of the Schur function sπ ≡ {π} by the basic M series of complete symmetric functions and the L = M-1 series of elementary symmetric functions. Our main technical tool is that of Hopf algebras and our main result is the derivation of a coproduct for any Schur function series obtained by plethysm from another such series. Therefrom one easily obtains π-generalized Newell-Littlewood formulae and the algebra of the formal group characters of these subgroups is established. Concrete examples and extensive tabulations are displayed for H13, H21 and H3, showing their involved and nontrivial representation theory. The nature of the subgroups is shown to be in general affine and in some instances non-reductive. We discuss the complexity of the coproduct formula and give a graphical notation to cope with it. We also discuss the way in which the group branching laws can be reinterpreted as twisted structures deformed by highly nontrivial 2-cocycles. The algebra of subgroup characters is identified as a cliffordization of the algebra of symmetric functions for GL(n) formal characters. Modification rules are beyond the scope of the present paper, but are briefly discussed

  19. Recursive algorithms, branching coefficients and applications

    CERN Document Server

    Lyakhovsky, Vladimir

    2010-01-01

    Recurrent relations for branching coefficients in affine Lie algebras integrable highest weight modules are studied. The decomposition algorithm based on the injection fan technique is adopted to the situation where the Weyl denominator becomes singular with respect to a reductive subalgebra. We study some modifications of the injection fan technique and demonstrate that it is possible to define the "subtracted fans" that play the role similar to the original ones. Possible applications of subtracted fans in CFT models are considered.

  20. Branch Retinal Vein Occlusion and Its Management

    Institute of Scientific and Technical Information of China (English)

    Desmond; Archer

    1992-01-01

    The natural course of Branch Retinal Vein Occlusion is determined by the site and completeness of the occlusion, the integrity of arterial perfusion to the affected sector and the efficiency of the developing collateral circulation. Most patients with tributary vein occlusion have some capillary fall out and microvascular incompetence in the distribution of the affected retina and vision is significantly compromised in over 50% of patients who have either chronic macular oedema or ischemia involving the...

  1. Computers in Some Branches of Applied Physiology .

    Directory of Open Access Journals (Sweden)

    S.S. Verma

    1994-04-01

    Full Text Available This paper reviews the applications of computers in the evaluation of different types of problems occuring in some branches of applied physiology. The recent applications of computers to perform advanced multivariate regression analysis for developing regression models in applied physiology are also highlighted. The regression models are practical significance for screening personnel in defence services, mines, industrial works, sports and the like.

  2. The making of a branching annelid

    OpenAIRE

    Aguado, M. Teresa; Glasby, Christopher J.; Schroeder, Paul C.; Weigert, Anne; Bleidorn, Christoph

    2015-01-01

    Ramisyllis multicaudata is a member of Syllidae (Annelida, Errantia, Phyllodocida) with a remarkable branching body plan. Using a next-generation sequencing approach, the complete mitochondrial genomes of R. multicaudata and Trypanobia sp. are sequenced and analysed, representing the first ones from Syllidae. The gene order in these two syllids does not follow the order proposed as the putative ground pattern in Errantia. The phylogenetic relationships of R. multicaudata are discerned usin...

  3. [Geometry and algebra of branches of the middle cerebral artery].

    Science.gov (United States)

    Blinkov, S M

    1986-01-01

    A classification of the cortical branches of the middle cerebral artery (MCA) is suggested by means of which each branch in any hemisphere can be qualified and identified in any variant of MCA branching. The principle of the classification consists in grouping the branches into arteries and trunks of the second, third, etc. order. Branches supplying blood to a certain sector of the lateral surface of the hemisphere are designated arteries. Their number and zone of branching are constant. Branches giving rise to 2 and more arteries are named trunks. Branching of the trunks, the number of trunks of the second, third, etc. order, and the site and type of origin of the arteries are extremely variable. Each trunk can be designated by a formula stating its order and the name of the artery supplied by this trunk. The arrangement of the MCA branches on the surface of the gyri and deep in the sulci, represented on the map of the lateral surface of the hemisphere, is designated conditionally as geometry of MCA branches. The order of branching of the trunks and the type of origin of the arteries, represented on abstract maps of the lateral surface of the hemisphere, are designated conditionally as algebra of the MCA branches. The variability of the geometry and algebra of the MCA branches must be taken into consideration in operations for extra-intracranial microanastomosis and in endovasal intervention on the MCA. PMID:3811741

  4. Topographical anatomy features of branching of nerves of lower extremities of rat

    Directory of Open Access Journals (Sweden)

    Tsarev A.A.

    2008-01-01

    Full Text Available 12 white rats of the reproductive period were the material for research. The topography of sciatic and femoral nerves of lower extremities of rats were studied by the method of level-by-level preparation. Femoral and sciatic nerves, their branches are ventral branches lumbar and sacral plexuses. Sciatic nerve was characterized by dispersed type of ramifying (78 % of cases, for the femoral nerve – the main type of branching (86%. The femoral nerve is projected on a medial surface of a hip and in the region of knee joint lies superficially that has a practical value. The rest portion of femoral nerve is located in hard-to-reach areas in the view of preparation and experimental approach. The sciatic nerve is projected on the skin of dorsal surfaces of pelvic areas where it leaves sciatic notch. For more reliable results of experimental research we propose to took into account age, sex, and topographical features.

  5. Measurements of $\\Xi_c^{+}$ Branching Ratios

    CERN Document Server

    Link, J M; Anjos, J C; Bediaga, I; Göbel, C; Magnin, J; Massafferri, A; De Miranda, J M; Pepe, I M; Polycarpo, E; Dos Reis, A C; Carrillo, S; Casimiro, E; Cuautle, E; Sánchez-Hernández, A; Uribe, C; Vázquez, F; Agostino, L; Cinquini, L; Cumalat, J P; O'Reilly, B; Segoni, I; Wahl, M; Butler, J N; Cheung, H W K; Chiodini, G; Gaines, I; Garbincius, P H; Garren, L A; Gottschalk, E E; Kasper, P H; Kreymer, A E; Kutschke, R; Wang, M; Benussi, L; Bertani, M; Bianco, S; Fabbri, Franco Luigi; Zallo, A; Reyes, M; Cawlfield, C; Kim, D Y; Rahimi, A; Wiss, J; Gardner, R; Kryemadhi, A; Chung, Y S; Kang, J S; Ko, B R; Kwak, J W; Lee, K B; Cho, K; Park, H; Alimonti, G; Barberis, S; Boschini, M; Cerutti, A; D'Angelo, P; Di Corato, M; Dini, P; Edera, L; Erba, S; Giammarchi, M; Inzani, P; Leveraro, F; Malvezzi, S; Menasce, D; Mezzadri, M; Moroni, L; Pedrini, D; Pontoglio, C; Prelz, F; Rovere, M; Sala, S; Davenport, T F; Arena, V; Boca, G; Bonomi, G; Gianini, G; Liguori, G; Lopes-Pegna, D; Merlo, M M; Pantea, D; Ratti, S P; Riccardi, C; Vitulo, P; Hernández, H; López, A M; Luiggi, E; Méndez, H; Paris, A; Quinones, J; Ramírez, J E; Zhang, Y; Wilson, J R; Handler, T; Mitchell, R; Engh, D; Hosack, M; Johns, W E; Nehring, M S; Sheldon, P D; Stenson, K; Vaandering, E W; Webster, M; Sheaff, M

    2003-01-01

    Using data collected by the fixed target Fermilab experiment FOCUS, we measure the branching ratios of the Cabibbo favored decays $\\Xi_c^+ \\to \\Sigma^+K^-\\pi^+$, $\\Xi_c^+ \\to \\Sigma^+ \\bar{K}^{*}(892)^0$, and $\\Xi_c^+ \\to \\Lambda^0K^-\\pi^+\\pi^+$ relative to $\\Xi_c^+ \\to \\Xi^-\\pi^+\\pi^+$ to be $0.91\\pm0.11\\pm0.04$, $0.78\\pm0.16\\pm0.06$, and $0.28\\pm0.06\\pm0.06$, respectively. We report the first observation of the Cabibbo suppressed decay $\\Xi_c^+ \\to \\Sigma^+K^+K^-$ and we measure the branching ratio relative to $\\Xi_c^+ \\to \\Sigma^+K^-\\pi^+$ to be $0.16\\pm0.06\\pm0.01$. We also set 90% confidence level upper limits for $\\Xi_c^+ \\to \\Sigma^+ \\phi$ and $\\Xi_c^+ \\to \\Xi^*(1690)^0(\\Sigma^+ K^-) K^+$ relative to $\\Xi_c^+ \\to \\Sigma^+K^-\\pi^+$ to be 0.12 and 0.05, respectively. We find an indication of the decays $\\Xi_c^+ \\to \\Omega^-K^{+}\\pi^+$ and $\\Xi_c^+ \\to \\Sigma^{*}(1385)^+ \\bar{K}^0$ and set 90% confidence level upper limits for the branching ratios with respect to $\\Xi_c^+ \\to \\Xi^-\\pi^+\\pi^+$ to be 0.12 a...

  6. Pebbles and Branching Programs for Tree Evaluation

    CERN Document Server

    Cook, Stephen; Wehr, Dustin; Braverman, Mark; Santhanam, Rahul

    2010-01-01

    We introduce the Tree Evaluation Problem, show that it is in logDCFL (and hence in P), and study its branching program complexity in the hope of eventually proving a superlogarithmic space lower bound. The input to the problem is a rooted, balanced d-ary tree of height h, whose internal nodes are labeled with d-ary functions on [k] = {1,...,k}, and whose leaves are labeled with elements of [k]. Each node obtains a value in [k] equal to its d-ary function applied to the values of its d children. The output is the value of the root. We show that the standard black pebbling algorithm applied to the binary tree of height h yields a deterministic k-way branching program with Theta(k^h) states solving this problem, and we prove that this upper bound is tight for h=2 and h=3. We introduce a simple semantic restriction called "thrifty" on k-way branching programs solving tree evaluation problems and show that the same state bound of Theta(k^h) is tight (up to a constant factor) for all h >= 2 for deterministic thrift...

  7. The root of branching river networks.

    Science.gov (United States)

    Perron, J Taylor; Richardson, Paul W; Ferrier, Ken L; Lapôtre, Mathieu

    2012-12-01

    Branching river networks are one of the most widespread and recognizable features of Earth's landscapes and have also been discovered elsewhere in the Solar System. But the mechanisms that create these patterns and control their spatial scales are poorly understood. Theories based on probability or optimality have proven useful, but do not explain how river networks develop over time through erosion and sediment transport. Here we show that branching at the uppermost reaches of river networks is rooted in two coupled instabilities: first, valleys widen at the expense of their smaller neighbours, and second, side slopes of the widening valleys become susceptible to channel incision. Each instability occurs at a critical ratio of the characteristic timescales for soil transport and channel incision. Measurements from two field sites demonstrate that our theory correctly predicts the size of the smallest valleys with tributaries. We also show that the dominant control on the scale of landscape dissection in these sites is the strength of channel incision, which correlates with aridity and rock weakness, rather than the strength of soil transport. These results imply that the fine-scale structure of branching river networks is an organized signature of erosional mechanics, not a consequence of random topology. PMID:23222614

  8. Analysis of the horizontal corneal diameter, central corneal thickness, and axial length in premature infants

    Directory of Open Access Journals (Sweden)

    Ozdemir Ozdemir

    2014-08-01

    Full Text Available Purpose: To determine the horizontal corneal diameter, central corneal thickness, and axial length in premature infants. Methods: Infants with a birth weight of less than 2,500 g or with a gestation period of less than 36 weeks were included in the study. Infants with retinopathy of prematurity (ROP were allocated to Group 1 (n=138, while those without ROP were allocated to Group 2 (n=236. All infants underwent a complete ophthalmologic examination, including corneal diameter measurements, pachymetry, biometry, and fundoscopy. Between-group comparisons of horizontal corneal diameter, central corneal thickness, and axial lengths were performed. Independent sample t-tests were used for statistical analysis. Results: Data was obtained from 374 eyes of 187 infants (102 female, 85 male. The mean gestational age at birth was 30.7 ± 2.7 weeks (range 25-36 weeks, the mean birth weight was 1,514 ± 533.3 g (range 750-1,970 g, and the mean postmenstrual age at examination was 40.0 ± 4.8 weeks. The mean gestational age and the mean birth weight of Group 1 were statistically lower than Group 2 (p0.05. Conclusions: The presence of ROP in premature infants does not alter the horizontal corneal diameter, central corneal thickness, or axial length.

  9. Predictors of Side Branch Compromise and related early complications after percutaneous coronary intervention

    Directory of Open Access Journals (Sweden)

    Nozari Y

    2007-07-01

    Full Text Available Background: Percutaneous Coronary Intervention (PCI for bifurcated lesions is associated with a low rate of success and high rate of complications compared to such treatment of lesions of most other morphologies. Symptoms occurring at the time of procedure caused by PCI may require additional angiography with or without stenting through stent struts, which subsequently increases risks of restenosis and stent thrombosis. The purpose of this study was to evaluate the incidence of major side branch (>1mm complications during PCI and their clinical, angiographic, and interventional predictors. Methods: Of 104 consecutive patients, we evaluated 50 lesions with ostial stenosis (group 1 and 54 lesions without ostial stenosis (group 2 as a control group. Age, sex, major coronary artery disease risk factors, and left ventricular ejection fraction (LVEF, were compared between groups. Morphology, location, type of lesion, length of lesion, main and side branch diameters, interventional approach, and clinical and interventional outcomes were the main variables studied during this trial. Results: Side Branch Compromise (SBC occurred in 41 (39.4% of the total number of cases: 52% in group 1 and 27.8% in group 2 (p=0.01. More than 80% of SBC occurred in main branches with stenosis (p=0.02. SBC did not correlate with clinical characteristics, bifurcation location, LVEF, or stent number. Chest pain was reported in 18% of the cases during or after PCI. Three non Q wave myocardial infarctions (MI occurred after SBC, each with >2 mm branch diameters (p=0.02. SBC was not associated with adverse clinical outcomes. Conclusion: The risk of MI after losing the side branch of a bifurcation lesion is not usually as high as it is after losing the main branch. Furthermore, it may not be a serious problem as one of the problems of the bifurcation lesion is the high rate of post procedural non Q wave MI associated with SBC. These findings demonstrate that side branch ostial

  10. Experimental study on the flow patterns and the two-phase pressure drops in a horizontal impacting T-Junction

    International Nuclear Information System (INIS)

    The present paper analyzes the experimental results concerning the flow patterns and pressure drops in two-phase flow through a horizontal impacting T-junction, whose outlet pipes are aligned and perpendicular to the inlet pipe. The test section consists of plexiglass pipes with inner diameter of 10 mm. A mixture of water and air at ambient temperature and pressures up to 2.4 bar flows through the T-junction, with different splitting of flow rates in the two outlet branches; superficial velocities of air and water in the inlet pipe have been varied up to a maximum of 35 m/s and 3.5 m/s respectively. The flow patterns occurring in the inlet and branch pipes are compared with the predictions of the Baker and Taitel – Dukler maps. The pressure drops along the branches have been measured relatively to different splitting of the flow rate through the two branches and the pressure loss coefficients in the junction have been evaluated. Friction pressure drops have allowed us to evaluate two-phase friction multipliers, which have then been compared to the predictions of Lockhart-Martinelli, and Friedel correlations. Local pressure drops have been extrapolated at the junction centre and analyzed; the two-phase multiplier has been evaluated and compared with the predictions of Chisholm correlation; the value of the empirical coefficient that minimizes the discrepancy has also been evaluated.

  11. Experimental study on the flow patterns and the two-phase pressure drops in a horizontal impacting T-Junction

    Science.gov (United States)

    Bertani, C.; Malandrone, M.; Panella, B.

    2014-04-01

    The present paper analyzes the experimental results concerning the flow patterns and pressure drops in two-phase flow through a horizontal impacting T-junction, whose outlet pipes are aligned and perpendicular to the inlet pipe. The test section consists of plexiglass pipes with inner diameter of 10 mm. A mixture of water and air at ambient temperature and pressures up to 2.4 bar flows through the T-junction, with different splitting of flow rates in the two outlet branches; superficial velocities of air and water in the inlet pipe have been varied up to a maximum of 35 m/s and 3.5 m/s respectively. The flow patterns occurring in the inlet and branch pipes are compared with the predictions of the Baker and Taitel - Dukler maps. The pressure drops along the branches have been measured relatively to different splitting of the flow rate through the two branches and the pressure loss coefficients in the junction have been evaluated. Friction pressure drops have allowed us to evaluate two-phase friction multipliers, which have then been compared to the predictions of Lockhart-Martinelli, and Friedel correlations. Local pressure drops have been extrapolated at the junction centre and analyzed; the two-phase multiplier has been evaluated and compared with the predictions of Chisholm correlation; the value of the empirical coefficient that minimizes the discrepancy has also been evaluated.

  12. Performance of horizontal versus vertical vapor extraction wells

    International Nuclear Information System (INIS)

    Vapor extraction wells used for site remediation of volatile organic chemicals in the vadose zone are typically vertical wells. Over the past few years, there has been an increased interest in horizontal wells for environmental remediation. Despite the interest and potential benefits of horizontal wells, there has been little study of the relative performance of horizontal and vertical vapor extraction wells. This study uses numerical simulations to investigate the relative performance of horizontal versus vertical vapor extraction wells under a variety of conditions. The most significant conclusion that can be drawn from this study is that in a homogeneous medium, a single, horizontal vapor extraction well outperforms a single, vertical vapor extraction well (with surface capping) only for long, linear plumes. Guidelines are presented regarding the use of horizontal wells

  13. 77 FR 64525 - National Institute on Aging; Notice of Closed Meeting

    Science.gov (United States)

    2012-10-22

    ..., (Telephone Conference Call). Contact Person: Elaine Lewis, Ph.D., Scientific Review Branch, National... Committee: National Institute on Aging Special Emphasis Panel Tuberculosis Infection in the Elderly....

  14. Evaluation of allowable external pressure for branch pipe connections

    International Nuclear Information System (INIS)

    Although the allowable external pressure for branch pipe connections is estimated by evaluation procedure for straight pipe, the applicability of this procedure has not been clear. That was discussed in this study. The buckling pressure of branch pipe connections was estimated by linear eigenvalue analysis with FEA (Finite Element Analysis). The types of branch pipe connections were T-joints and T-pipes. The ranges of configurations in branch pipe connections for FEA were determined by survey of branch pipe connections in the Japanese nuclear power plants. The results of the FEA showed that the buckling strength of branch pipe was found sufficiently to be superior to that of straight piping from comparisons of estimations by FEA for branch pipe connections and those by formula for straight pipe in the design code. It was concluded that the formula for straight pipe is applicable for the evaluation of allowable external pressure for branch pipe connections. (author)

  15. Differentiation of crack branching types in fractured glass

    Science.gov (United States)

    Rabinovitch, A.; Bahat, D.

    2011-07-01

    The influence of different physical factors on the fracture branching phenomenon was investigated on a fractured brittle (glass) bottle. A fully branched fracture tree consisting of 144 initiation sites was induced. Branching sites were concentrated in two zones: close to the fracture origin and further away from it along the bottle axis, which was shown to be related to reflection of transverse acoustic waves from the bottle's shoulder. Two types of branching formed, complete full branches (FB), and attempted branching (AB) when one branch was shorter than 5 mm. Branching in the first zone was shown to be regulated by both the distribution of flaw lengths and the distances from each FB to its nearest fracture neighbor. Fracture spacing was found to be proportional to the stress at the propagating fracture tips.

  16. Bifurcation phenomena in thermal convection in horizontal, concentric annuli containing saturated porous media

    International Nuclear Information System (INIS)

    A saturated porous medium confined between two horizontal cylinders is considered. As a result of a temperature difference between the cylinders, thermal convection is induced in the medium. The fluid motion is described by the 2-D Darcy-Oberbeck-Boussinesq's (DOB) equations, which the authors' solve using regular perturbation expansion. The steady state problem is solved using Newton's technique. At each step the determinant of the Jacobian is evaluated. Bifurcation points are identified with singularities of the Jacobian. Linear stability analysis is used to determine the stability of various solution branches. The results they obtained from solving the DOB equations using perturbations expansion are compared with those they obtained from solving the nonlinear PDE's numerically and are found to favorably agree

  17. Aging Skin

    Science.gov (United States)

    ... email address Submit Home > Healthy Aging > Wellness Healthy Aging Aging skin More information on aging skin When it ... treated early. Return to top More information on Aging skin Read more from womenshealth.gov Varicose Veins ...

  18. Why Horizontal Inequalities are Important for a Shared Society

    OpenAIRE

    Frances Stewart

    2014-01-01

    This article argues that low horizontal inequalities, or inequalities among groups, should form an intrinsic aspect of a shared society. It argues, on the basis of several philosophical analyses, that horizontal inequalities are not only unjust, but they also contribute to violent conflict and lack of social cohesion. Although low horizontal inequalities appear to be an implicit aspect of the shared society project it would be an advantage to include them explicitly, from the perspective of a...

  19. Repair of horizontal root fracture: A case report

    OpenAIRE

    Laila Shafie; Farhad Farzaneh; Maryam Alsadat Hashemipour

    2011-01-01

    ABSTRACT: Horizontal root fractures in permanent teeth are uncommon injuries among dental traumas. The principle of treating horizontal root fractures of permanent teeth is repositioning and fixation of fractured segment. Diagnosis of tooth fractures based on radiographic findings and the fracture healing process are affected by factors before and after injury. The present case reports the treatment of horizontal root fracture located at the apical-third of upper left and right central inciso...

  20. Calcium as a branching signal in Neurospora crassa.

    OpenAIRE

    Reissig, J L; Kinney, S G

    1983-01-01

    The divalent cation ionophore A23187 was found to induce apical branching in Neurospora crassa. Optimal effects were obtained by treatment with 0.1 mM ionophore for 30 min. Branching first became manifest during or shortly after treatment; successive rounds of branching could be observed at later times. Calcium starvation of the mycelium markedly reduced its subsequent response to the ionophore, whereas starvation for other divalent cations had no detectable effect. The branching response was...

  1. Statistics of branched flow in a weak correlated random potential

    OpenAIRE

    Kaplan, Lev

    2002-01-01

    Recent images of electron flow through a two-dimensional electron gas (2DEG) device show branching behavior that is reproduced in numerical simulations of motion in a correlated random potential [cond-mat/0010348]. We show how such branching naturally arises from caustics in the classical flow and find a simple scaling behavior of the branching under variation of the random potential strength. Analytic results describing the statistical properties of the branching are confirmed by classical a...

  2. Characterizing Weighted MSO for Trees by Branching Transitive Closure Logics

    OpenAIRE

    Fülöp, Zoltán; Vogler, Heiko

    2012-01-01

    We introduce the branching transitive closure operator on weighted monadic second-order logic formulas where the branching corresponds in a natural way to the branching inherent in trees. For arbitrary commutative semirings, we prove that weighted monadic second order logics on trees is equivalent to the definability by formulas which start with one of the following operators: (i) a branching transitive closure or (ii) an existential second-order quantifier followed by one universal first-ord...

  3. Spondylolysis and the sacro-horizontal angle in athletes

    International Nuclear Information System (INIS)

    The frequency of spondylolysis and the relationship between spondylolysis and the sacro-horizontal angle in 143 athletes and 30 non-athletes is reported. Athletes had a larger sacro-horizontal angle than non-athletes. The sacro-horizontal angle was larger in athletes with spondylolysis as compared with those without. An increased incidence of spondylolysis with an increased angle was demonstrated. It is suggested that an increased sacro-horizontal angle may predispose to spondylolysis, especially in combination with the high mechanical loads sustained in certain sports. (orig.)

  4. Small horizontal emittance in the TESLA damping ring

    International Nuclear Information System (INIS)

    The present TESLA damping ring is designed for a normalized horizontal emittance of 8x10-6 m. γ-γ collisions at the TESLA linear collider will benefit from a further decrease of the horizontal emittance. This paper reviews the processes which limit the horizontal emittance in the damping ring. Preliminary estimates on the smallest horizontal emittance for the present TESLA damping ring design as well as an ultimate limit of the emittance reachable with the TESLA damping ring concept will be given

  5. 40 CFR 721.10094 - Decene, branched and linear.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Decene, branched and linear. 721.10094... Substances § 721.10094 Decene, branched and linear. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as decene, branched and linear (PMN P-03-272;...

  6. RELATIONSHIPS AMONG SPRINT VELOCITIES, HORIZONTAL GROUND REACTION FORCE, AND ISOKINETIC TRUNK STRENGTH VARIABLES

    OpenAIRE

    Kale Mehmet; Kirkaya I

    2013-01-01

    The purpose of this study was to investigate the relationships among sprint velocities, horizontal ground reaction force, and isokinetic trunk strength variables. Voluntary 19 athletes were participated to the study [age (year)= 20.9±2.3, training age (month)= 91.3±48.2, body height (cm)= 173.1±6.5, body weight (kg)= 64.7±8.4] from different sports including in explosive strength. Sprints (10m, 20m, 30m, and 40m) were tested on a non-motorized treadmill. Velocities (V10m, V20m, V30m, and V40m...

  7. Demonstration of a utility industry horizontal drilling system: Horizontal well AMH-5 installation report

    International Nuclear Information System (INIS)

    The Department of Energy's Office of Technology Development initiated an integrated demonstration of innovative technologies and systems for cleanup of VOCs in soils and groundwater at the Savannah River Site (SRS) in 1989. The overall goal of the program is demonstration of multiple technologies and systems in the fields of drilling, characterization, monitoring, and remediation at a single test bed. Innovative technologies are compared to one another and to baseline technologies in terms of technical performance and cost effectiveness. Transfer of successfully demonstrated technologies and systems to DOE environmental restoration organizations, to other government agencies, and to industry is a critical part of the program. Directional drilling has been shown to be a successful technique for enhancing access to the subsurface, thus improving remediation systems, especially remediation systems which perform in situ. Demonstration of an innovative directional drilling system at the Integrated Demonstration Site at the SRS, was initiated in June of 1992. The directional drilling system was designed to install an in situ remediation system. The drilling system is an experimental compaction/dry drilling technique developed by Charles Machine Works (Ditch Witch reg-sign) of Perry, Oklahoma. A horizontal well was installed in the M Area of the SRS below and parallel to an abandoned tile process sewer line. The installation of the horizontal well was a two-part process. Part one consisted of drilling the borehole, and part two was the horizontal well completion

  8. Highly branched dextrin prepared from high-amylose maize starch using waxy rice branching enzyme (WRBE).

    Science.gov (United States)

    Tian, Yaoqi; Chen, Huangli; Zhang, Xiwen; Zhan, Jinling; Jin, Zhengyu; Wang, Jinpeng

    2016-07-15

    Branching enzyme (BE, EC 2.4.1.18) was isolated from the developing waxy rice endosperm and used to prepare a highly branched dextrin based on high-amylose maize starch (HAMS) as a substrate. The molecular mass of the starch initially degraded quickly from 2.5×10(7) to 4.1×10(5)Da, and then stabilized, with a minimal increase during the BE treatment. The resultant branched dextrin had a narrow size distribution, with a mean molecular weight of 5.1×10(5)Da and a polydispersity index (PI) of 1.567. The results of high-performance anion exchange chromatography indicated that the degree of polymerization (DP) of the branched chains ranged from 3 to 27; approximately 75.26% of these chains were short (DP<10). These findings suggest that the isolated BE can cleave long chains into oligosaccharides, subsequently transferring oligosaccharides into highly branched dextrins with a narrow size distribution and short side chains. PMID:26948647

  9. Determinants of Human Immunodeficiency Virus (HIV prevalence in homosexual and bisexual men screened for admission to a cohort study of HIV negatives in Belo Horizonte, Brazil: Project Horizonte

    Directory of Open Access Journals (Sweden)

    Carneiro Mariângela

    2003-01-01

    Full Text Available Project Horizonte, an open cohort of homosexual and bisexual human immunodeficiency virus (HIV-1 negative men, is a component of the AIDS Vaccine Program, in Belo Horizonte, Minas Gerais, Brazil. The objective of this study was to compare volunteers testing HIV positive at cohort entry with a sample of those who tested HIV negative in order to identify risk factors for prevalent HIV infection, in a population being screened for enrollment at Project Horizonte. A nested case-control study was conducted. HIV positive volunteers at entry (cases were matched by age and admission date to three HIV negative controls each. Selected variables used for the current analysis included demographic factors, sexual behavior and other risk factors for HIV infection. During the study period (1994-2001, among the 621 volunteers screened, 61 tested positive for HIV. Cases were matched to 183 HIV negative control subjects. After adjustments, the main risk factors associated with HIV infection were unprotected sex with an occasional partners, OR = 3.7 (CI 95% 1.3-10.6, receptive anal intercourse with an occasional partner, OR = 2.8 (95% CI 0.9-8.9 and belonging to the negro racial group, OR = 3.4 (CI 95% 1.1-11.9. These variables were associated with an increase in the risk of HIV infection among men who have sex with men at the screening for admission to an open HIV negative cohort.

  10. Shallow water model for horizontal centrifugal casting

    Science.gov (United States)

    Boháček, J.; Kharicha, A.; Ludwig, A.; Wu, M.

    2012-07-01

    A numerical model was proposed to simulate the solidification process of an outer shell of work roll made by the horizontal centrifugal casting technique. Shallow water model was adopted to solve the 2D average flow dynamics of melt spreading and the average temperature distribution inside the centrifugal casting mould by considering the centrifugal force, Coriolis force, viscous force due to zero velocity on the mould wall, gravity, and energy transport by the flow. Additionally, a 1D sub-model was implemented to consider the heat transfer in the radial direction from the solidifying shell to the mould. The solidification front was tracked by fulfilling the Stefan condition. Radiative and convective heat losses were included from both, the free liquid surface and the outer wall of the mould. Several cases were simulated with the following assumed initial conditions: constant height of the liquid metal (10, 20, and 30 mm), uniform temperature of the free liquid surface (1755 K). The simulation results have shown that while the solidification front remained rather flat, the free surface was disturbed by waves. The amplitude of waves increased with the liquid height. Free surface waves diminished as the solidification proceeded.

  11. Horizontal Shear Wave Imaging of Large Optics

    Energy Technology Data Exchange (ETDEWEB)

    Quarry, M J

    2007-09-05

    When complete the National Ignition Facility (NIF) will be the world's largest and most energetic laser and will be capable of achieving for the first time fusion ignition in the laboratory. Detecting optics features within the laser beamlines and sizing them at diameters of 0.1 mm to 10 mm allows timely decisions concerning refurbishment and will help with the routine operation of the system. Horizontally polarized shear waves at 10 MHz were shown to accurately detect, locate, and size features created by laser operations from 0.5 mm to 8 mm by placing sensors at the edge of the optic. The shear wave technique utilizes highly directed beams. The outer edge of an optic can be covered with shear wave transducers on four sides. Each transducer sends a pulse into the optic and any damage reflects the pulse back to the transmitter. The transducers are multiplexed, and the collected time waveforms are enveloped and replicated across the width of the element. Multiplying the data sets from four directions produces a map of reflected amplitude to the fourth power, which images the surface of the optic. Surface area can be measured directly from the image, and maximum depth was shown to be correlated to maximum amplitude of the reflected waveform.

  12. Sheared bioconvection in a horizontal tube

    Science.gov (United States)

    Croze, O. A.; Ashraf, E. E.; Bees, M. A.

    2010-12-01

    The recent interest in using microorganisms for biofuels is motivation enough to study bioconvection and cell dispersion in tubes subject to imposed flow. To optimize light and nutrient uptake, many microorganisms swim in directions biased by environmental cues (e.g. phototaxis in algae and chemotaxis in bacteria). Such taxes inevitably lead to accumulations of cells, which, as many microorganisms have a density different to the fluid, can induce hydrodynamic instabilites. The large-scale fluid flow and spectacular patterns that arise are termed bioconvection. However, the extent to which bioconvection is affected or suppressed by an imposed fluid flow and how bioconvection influences the mean flow profile and cell transport are open questions. This experimental study is the first to address these issues by quantifying the patterns due to suspensions of the gravitactic and gyrotactic green biflagellate alga Chlamydomonas in horizontal tubes subject to an imposed flow. With no flow, the dependence of the dominant pattern wavelength at pattern onset on cell concentration is established for three different tube diameters. For small imposed flows, the vertical plumes of cells are observed merely to bow in the direction of flow. For sufficiently high flow rates, the plumes progressively fragment into piecewise linear diagonal plumes, unexpectedly inclined at constant angles and translating at fixed speeds. The pattern wavelength generally grows with flow rate, with transitions at critical rates that depend on concentration. Even at high imposed flow rates, bioconvection is not wholly suppressed and perturbs the flow field.

  13. Sheared bioconvection in a horizontal tube

    International Nuclear Information System (INIS)

    The recent interest in using microorganisms for biofuels is motivation enough to study bioconvection and cell dispersion in tubes subject to imposed flow. To optimize light and nutrient uptake, many microorganisms swim in directions biased by environmental cues (e.g. phototaxis in algae and chemotaxis in bacteria). Such taxes inevitably lead to accumulations of cells, which, as many microorganisms have a density different to the fluid, can induce hydrodynamic instabilites. The large-scale fluid flow and spectacular patterns that arise are termed bioconvection. However, the extent to which bioconvection is affected or suppressed by an imposed fluid flow and how bioconvection influences the mean flow profile and cell transport are open questions. This experimental study is the first to address these issues by quantifying the patterns due to suspensions of the gravitactic and gyrotactic green biflagellate alga Chlamydomonas in horizontal tubes subject to an imposed flow. With no flow, the dependence of the dominant pattern wavelength at pattern onset on cell concentration is established for three different tube diameters. For small imposed flows, the vertical plumes of cells are observed merely to bow in the direction of flow. For sufficiently high flow rates, the plumes progressively fragment into piecewise linear diagonal plumes, unexpectedly inclined at constant angles and translating at fixed speeds. The pattern wavelength generally grows with flow rate, with transitions at critical rates that depend on concentration. Even at high imposed flow rates, bioconvection is not wholly suppressed and perturbs the flow field

  14. Bubble growth in a narrow horizontal space

    International Nuclear Information System (INIS)

    The purpose of this work is to develop an axis-symmetric two-phase flow model describing the growth of a single bubble squeezed between a horizontal heated upward-facing disc and an insulating surface placed parallel to the heated surface. Heat transfers at the liquid-vapour interfaces are predicted by the kinetic limit of vaporisation. The depths of the liquid films deposed on the surfaces (heated surface and confinement space) are determined using the Moriyama and Inoue correlation (1996). Transient heat transfers within the heated wall are taken into account. The model is applied to pentane bubble growth. The influence of the gap size, the initial temperature of the system, the thermal effusivity of the heated wall and the kinetic limit of vaporisation are studied. The results show that the expansion of the bubbles strongly depends on the gap size and can be affected by the effusivity of the material. Mechanical inertia effects are mainly dominant at the beginning of the bubble expansion. Pressure drop induced by viscous effects have to be taken into account for high capillary numbers. Heat transfers at the meniscus are negligible except at the early stages of the bubble growth. (author)

  15. Thermal convection in a rotating horizontal annulus

    Science.gov (United States)

    Vjatkin, Alexey; Ivanova, Alevtina; Kozlov, Victor

    2014-11-01

    Thermal convection of viscous fluid in a coaxial horizontal gap rotating around its own axis is investigated experimentally. The temperature of inner boundary is higher than that of the outer one. The threshold of mean convection excitation is studied. It is found that, despite the stabilizing effect of the centrifugal force of inertia, the convection in the layer occurs in a threshold way at lowering the rotation velocity and is excited by thermovibrational mechanism. In viscous liquids crisis of heat transfer is associated with the appearance of vortices extended along the azimuth (three-dimensional structures), and the longitudinal two-dimensional rolls appear on the background of them. In the experiments with low-viscosity fluids the opposite sequence of convective processes development is observed. With the advent of convective structures their slow azimuthal drift relative to the cavity is registered. It is shown that the drift is associated with the azimuthal steady motion of the fluid, which is generated in Stokes layers near the boundaries. The increase of viscosity results in growth of wavelength of the longitudinal rolls and significant reduction of the velocity the drift of vortex system. Experimental results agree with theoretical predictions. The work was done in the frame of PSHPU Strategic Development Program (Project 029-F) and supported by RFBR (Grant 13-01-00675a).

  16. Horizontal stresses below two agricultural vehicles

    DEFF Research Database (Denmark)

    Lamande, Mathieu André Maurice; Munkholm, Lars Juhl; Nielsen, Janne Aalborg;

    and the number of wheels. We measured horizontal stress at two depths (0.3 and 0.5 m) below tires of two slurry spreaders: one self-propelled machine equipped with wide tires (1.050 m) and low inflation pressure (150 kPa) but carrying a high wheel load (120 kN), and one tractor towing a three-axle slurry...... at 0.3 than at 0.5 m for the tractor-trailer combination. At 0.3 m depth it was significantly higher for the tractor-trailer system than for the self-propelled machine. Generally, air permeability was reduced in the track of the tractor-trailer system, while no significant reduction was observed...... for the self-propelled system. Outside but close to the tracks, the latter system increased the air permeability (significantly at 0.3 m). Also the tractor-trailer system tended to increase the air permeability outside the track (significant when compared to the in-track values). Both systems reduced...

  17. Yaw dynamics of horizontal axis wind turbines

    Science.gov (United States)

    Hansen, A. C.

    1992-05-01

    Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw-controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they know they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.

  18. Yaw dynamics of horizontal axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.C. (Utah Univ., Salt Lake City, UT (United States))

    1992-05-01

    Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw- controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they known they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.

  19. Shallow water model for horizontal centrifugal casting

    International Nuclear Information System (INIS)

    A numerical model was proposed to simulate the solidification process of an outer shell of work roll made by the horizontal centrifugal casting technique. Shallow water model was adopted to solve the 2D average flow dynamics of melt spreading and the average temperature distribution inside the centrifugal casting mould by considering the centrifugal force, Coriolis force, viscous force due to zero velocity on the mould wall, gravity, and energy transport by the flow. Additionally, a 1D sub-model was implemented to consider the heat transfer in the radial direction from the solidifying shell to the mould. The solidification front was tracked by fulfilling the Stefan condition. Radiative and convective heat losses were included from both, the free liquid surface and the outer wall of the mould. Several cases were simulated with the following assumed initial conditions: constant height of the liquid metal (10, 20, and 30 mm), uniform temperature of the free liquid surface (1755 K). The simulation results have shown that while the solidification front remained rather flat, the free surface was disturbed by waves. The amplitude of waves increased with the liquid height. Free surface waves diminished as the solidification proceeded.

  20. Axisymmetric, Ventilated Supercavitation in Unsteady, Horizontal Flow

    Science.gov (United States)

    Kawakami, Ellison; Lee, Seung-Jae; Arndt, Roger

    2012-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, an artificial supercavity is required until the vehicle can reach conditions at which a natural supercavity can be sustained. Previous studies at Saint Anthony Falls Laboratory (SAFL) focused on the behavior of ventilated supercavities in steady horizontal flows. In open waters, vehicles can encounter unsteady flows, especially when traveling under waves. A study has been carried out at SAFL to investigate the effects of unsteady flow on axisymmetric supercavities. An attempt is made to duplicate sea states seen in open waters. In an effort to track cavity dimensions throughout a wave cycle, an automated cavity tracking script has been developed. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are presented. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. The supercavity volume varied with cavitation number and a possible relationship between the two is being explored. (Supported by ONR)

  1. Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus

    DEFF Research Database (Denmark)

    Beck, Hans Christian

    2005-01-01

    Fatty acid biosynthesis by a mutant strain of Staphylococcus carnosus deficient in branched-chain amino acid aminotransferase (IlvE) activity was analysed. This mutant was unable to produce the appropriate branched-chain alpha-ketoacid precursors for branched-chain fatty acid biosynthesis from th...

  2. Geology of the Cane Branch and Helton Branch watershed areas, McCreary County, Kentucky

    Science.gov (United States)

    Lyons, Erwin J.

    1957-01-01

    Cane Branch and Helton Branch in McCreary County, Kentucky, are about 1.4 miles apart (fig. 1). Can Branch, which is about 2.1 miles long, emptied into Hughes Fork of Beaver Creek. Its watershed area of about 1.5 square miles lies largely in the Wiborf 7 1/2-minute quadrangle (SW/4 Cumberland Falls 15-minute quadrangle), but the downstream part of the area extends northward into the Hail 7 1/2-minute quadrangle (NW/4 Cumberland Falls 15-minute quadrangle). Helton Branch, which is about 1.1 miles long, has two tributaries and empties into Little Hurricane Fork of Beaver Creek. It drains an area of about 0.8 square mile of while about 0.5 square mile is in the Hail quadrangle and the remainder in the Wilborg quadrangle. The total relief in the Can Branch area is about 500 feet and in the Helton Branch area about 400 feet. Narrow, steep-sided to canyon-like valley and winding ridges, typical of the Pottsville escarpment region, are characteristic of both areas. Thick woods and dense undergrowth cover much of the two areas. Field mapping was done on U.S. Geological Survey 7 1/2-minute maps having a scale of 1:24,000 and a contour interval of 20 feet. Elevations of lithologic contacts were determined with a barometer and a hand level. Aerial photographs were used principally to trace the cliffs formed by sandstone and conglomerate ledges. Exposures, except for those of the cliff- and ledge-forming sandstone and conglomerates, are not abundant. The most complete stratigraphic sections (secs. 3 and 4, fig. 2) in the two areas are exposed in cuts of newly completed Forest Service roads, but the rick in the upper parts of the exposures is weathered. To supplement these sections, additional sections were measured in cuts along the railroad and main highways in nor near the watersheds.

  3. Effects of Horizontal Acceleration on Human Visual Acuity and Stereopsis

    Directory of Open Access Journals (Sweden)

    Chi-Ting Horng

    2015-01-01

    Full Text Available The effect of horizontal acceleration on human visual acuity and stereopsis is demonstrated in this study. Twenty participants (mean age 22.6 years were enrolled in the experiment. Acceleration from two different directions was performed at the Taiwan High-Speed Rail Laboratory. Gx and Gy (< and >0.1 g were produced on an accelerating platform where the subjects stood. The visual acuity and stereopsis of the right eye were measured before and during the acceleration. Acceleration <0.1 g in the X- or Y-axis did not affect dynamic vision and stereopsis. Vision decreased (mean from 0.02 logMAR to 0.25 logMAR and stereopsis declined significantly (mean from 40 s to 60.2 s of arc when Gx > 0.1 g. Visual acuity worsened (mean from 0.02 logMAR to 0.19 logMAR and poor stereopsis was noted (mean from 40 s to 50.2 s of arc when Gy > 0.1 g. The effect of acceleration from the X-axis on the visual system was higher than that from the Y-axis. During acceleration, most subjects complained of ocular strain when reading. To our knowledge, this study is the first to report the exact levels of visual function loss during Gx and Gy.

  4. NASA Glenn Research Center Electrochemistry Branch Overview

    Science.gov (United States)

    Manzo, Michelle A.; Hoberecht, Mark; Reid, Concha

    2010-01-01

    This presentation covers an overview of NASA Glenn's history and heritage in the development of electrochemical systems for aerospace applications. Current programs related to batteries and fuel cells are addressed. Specific areas of focus are Li-ion batteries and Polymer Electrolyte Membrane Fuel cells systems and their development for future Exploration missions. The presentation covers details of current component development efforts for high energy and ultra high energy Li-ion batteries and non-flow-through fuel cell stack and balance of plant development. Electrochemistry Branch capabilities and facilities are also addressed.

  5. Branch Processes of Regular Magnetic Monopole

    Institute of Scientific and Technical Information of China (English)

    MO Shu-Fan; REN Ji-Rong; ZHU Tao

    2009-01-01

    In this paper, by making use of Duan's topological current theory, the branch process of regular magnetic monopoles is discussed in detail Regular magnetic monopoles are found generating or annihilating at the limit point and encountering, splitting, or merging at the bifurcation point and the degenerate point systematically of the vector order parameter field φ(x).Furthermore, it is also shown that when regular magnetic monopoles split or merge at the degenerate point of field function φ, the total topological charges of the regular magnetic monopoles axe still unchanged.

  6. A branching model for hadronic air showers

    CERN Document Server

    Novotny, Vladimir; Ebr, Jan

    2015-01-01

    We introduce a simple branching model for the development of hadronic showers in the Earth's atmosphere. Based on this model, we show how the size of the pionic component followed by muons can be estimated. Several aspects of the subsequent muonic component are also discussed. We focus on the energy evolution of the muon production depth. We also estimate the impact of the primary particle mass on the size of the hadronic component. Even though a precise calculation of the development of air showers must be left to complex Monte Carlo simulations, the proposed model can reveal qualitative insight into the air shower physics.

  7. Pebbles and Branching Programs for Tree Evaluation

    OpenAIRE

    Cook, Stephen; McKenzie, Pierre; Wehr, Dustin; Braverman, Mark; Santhanam, Rahul

    2010-01-01

    We introduce the Tree Evaluation Problem, show that it is in logDCFL (and hence in P), and study its branching program complexity in the hope of eventually proving a superlogarithmic space lower bound. The input to the problem is a rooted, balanced d-ary tree of height h, whose internal nodes are labeled with d-ary functions on [k] = {1,...,k}, and whose leaves are labeled with elements of [k]. Each node obtains a value in [k] equal to its d-ary function applied to the values of its d childre...

  8. Annual report, Materials Science Branch, FY 1992

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, S. [ed.

    1993-10-01

    This report summarizes the progress of the Materials Science Branch of the National Renewable Energy Laboratory (NREL) from October 1, 1991, through September 30, 1992. Six technical sections of the report cover these main areas of NREL`s in-house research: Crystal Growth, Amorphous Silicon, III-V High-Efficiency Photovoltaic Cells, Solid State Theory, Solid State Spectroscopy, and Program Management. Each section explains the purpose and major accomplishments of the work in the context of the US Department of Energy`s National Photovoltaic Research Program plans.

  9. Strategy of Irrigation Branch in Russia

    Science.gov (United States)

    Zeyliger, A.; Ermolaeva, O.

    2012-04-01

    At this moment, at the starting time of the program on restoration of a large irrigation in Russia till 2020, the scientific and technical community of irrigation branch does not have clear vision on how to promote a development of irrigated agriculture and without repeating of mistakes having a place in the past. In many respects absence of a vision is connected to serious backlog of a scientific and technical and informational and technological level of development of domestic irrigation branch from advanced one. Namely such level of development is necessary for the resolving of new problems in new conditions of managing, and also for adequate answers to new challenges from climate and degradation of ground & water resources, as well as a rigorous requirement from an environment. In such important situation for irrigation branch when it is necessary quickly generate a scientific and technical politics for the current decade for maintenance of translation of irrigated agriculture in the Russian Federation on a new highly effective level of development, in our opinion, it is required to carry out open discussion of needs and requirements as well as a research for a adequate solutions. From political point of view a framework organized in FP6 DESIRE 037046 project is an example of good practice that can serve as methodical approach how to organize and develop such processes. From technical point of view a technology of operational management of irrigation at large scale presents a prospective alternative to the current type of management based on planning. From point of view ICT operational management demands creation of a new platform for the professional environment of activity. This platform should allow to perceive processes in real time, at their partial predictability on signals of a straight line and a feedback, within the framework of variability of decision making scenarious, at high resolution and the big ex-awning of sensor controls and the gauges

  10. Logic, planning agency and branching time

    OpenAIRE

    Ricardo Souza Silvestre

    2010-01-01

    The purpose of this paper is to give a formal account of a kind of agency so far neglected in the field of philosophical modal logic of action: planning agency. In doing this we follow the standard approach of modal logics of agency exemplified by the works of Belnap, Chellas and Pörn. Since we believe there is a close relation between planning, time and indeterminism, we use the theory of branching time as a conceptual framework for investigating the basic features of planning agency. Beside...

  11. Novel Branches of (0,2) Theories

    CERN Document Server

    Quigley, Callum; Stern, Mark

    2012-01-01

    We show that recently proposed linear sigma models with torsion can be obtained from unconventional branches of conventional gauge theories. This observation puts models with log interactions on firm footing. If non-anomalous multiplets are integrated out, the resulting low-energy theory involves log interactions of neutral fields. For these cases, we find a sigma model geometry which is both non-toric and includes brane sources. These are heterotic sigma models with branes. Surprisingly, there are massive models with compact complex non-Kahler target spaces, which include brane/anti-brane sources. The simplest conformal models describe wrapped heterotic NS5-branes. We present examples of both types.

  12. Organization and targets of the European Branch

    Energy Technology Data Exchange (ETDEWEB)

    Cataldi, R.

    1997-12-01

    After a short historical review of the formation, objectives and organization of the International Geothermal Association (IGA), this paper describes the functions, goals and activities of the IGA European Branch. In particular, the paper illustrates the plan of action established for the periods 1993-`95 and 1996-`98, and the issues dealt with by the European Forum as of August 1996. The last section of the paper outlines the main problems to be faced in the near future in order to facilitate the aggregation of efforts, the amalgamation of promotional initiatives and the coordination of the basic activities needed for the consolidation and growth of the geothermal community in Europe. (orig.)

  13. Annual report, Basic Sciences Branch, FY 1991

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    This report summarizes the progress of the Basic Sciences Branch of the National Renewable Energy Laboratory (NREL) from October 1, 1990, through September 30, 1991. Seven technical sections of the report cover these main areas of NREL`s in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, Solid-State Spectroscopy, and Superconductivity. Each section explains the purpose and major accomplishments of the work in the context of the US Department of Energy`s National Photovoltaic Research Program plans.

  14. Branching of periodic orbits from Kukles isochrones

    Directory of Open Access Journals (Sweden)

    B. Toni

    1998-05-01

    Full Text Available We study local bifurcations of limit cycles from isochronous (or linearizable centers. The isochronicity has been determined using the method of Darboux linearization, which provides a birational linearization for the examples that we analyze. This transformation simplifies the analysis by avoiding the complexity of the Abelian integrals appearing in other approaches. As an application of this approach, we show that the Kukles isochrone (linear and nonlinear has at most one branch point of limit cycles. Moreover, for each isochrone, there are small perturbations with exactly one continuous family of limit cycles.

  15. Accelerator Physics Branch annual technical report, 1989

    International Nuclear Information System (INIS)

    The report describes, in a series of separate articles, the achievements of the Accelerator Physics Branch for the calendar year 1989. Work in basic problems of accelerator physics including ion sources, high-duty-factor rf quadrupoles, coupling effects in standing wave linacs and laser acceleration is outlined. A proposal for a synchrotron light source for Canada is described. Other articles cover the principal design features of the IMPELA industrial electron linac prototype, the cavities developed for the HERA complex at DESY, Hamburg, West Germany, and further machine projects that have been completed

  16. Effect of Vertical, Horizontal, and Combined Plyometric Training on Explosive, Balance, and Endurance Performance of Young Soccer Players.

    Science.gov (United States)

    Ramírez-Campillo, Rodrigo; Gallardo, Francisco; Henriquez-Olguín, Carlos; Meylan, Cesar M P; Martínez, Cristian; Álvarez, Cristian; Caniuqueo, Alexis; Cadore, Eduardo L; Izquierdo, Mikel

    2015-07-01

    The aim of this study was to compare the effects of 6 weeks of vertical, horizontal, or combined vertical and horizontal plyometric training on muscle explosive, endurance, and balance performance. Forty young soccer players aged between 10 and 14 years were randomly divided into control (CG; n = 10), vertical plyometric group (VG; n = 10), horizontal plyometric group (HG; n = 10), and combined vertical and horizontal plyometric group (VHG; n = 10). Players performance in the vertical and horizontal countermovement jump with arms, 5 multiple bounds test (MB5), 20-cm drop jump reactive strength index (RSI20), maximal kicking velocity (MKV), sprint, change of direction speed (CODS), Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1), and balance was measured. No significant or meaningful changes in the CG, apart from small change in the Yo-Yo IR1, were observed while all training programs resulted in meaningful changes in explosive, endurance, and balance performance. However, only VHG showed a statistically significant (p ≤ 0.05) increase in all performance test and most meaningful training effect difference with the CG across tests. Although no significant differences in performance changes were observed between experimental groups, the VHG program was more effective compared with VG (i.e., jumps, MKV, sprint, CODS, and balance performance) and HG (i.e., sprint, CODS, and balance performance) to small effect. The study demonstrated that vertical, horizontal, and combined vertical and horizontal jumps induced meaningful improvement in explosive actions, balance, and intermittent endurance capacity. However, combining vertical and horizontal drills seems more advantageous to induce greater performance improvements. PMID:25559903

  17. The Asymptotic Giant Branch and the Tip of the Red Giant Branch as Probes of Star Formation History: The Nearby Dwarf Irregular Galaxy KKH 98

    CERN Document Server

    Melbourne, J; Dalcanton, J; Ammons, S M; Max, C; Koo, D C; Girardi, Leo; Dolphin, A

    2010-01-01

    We investigate the utility of the asymptotic giant branch (AGB) and the red giant branch (RGB) as probes of the star formation history (SFH) of the nearby (D=2.5 Mpc) dwarf irregular galaxy, KKH 98. Near-infrared (IR) Keck Laser Guide Star Adaptive Optics (AO) images resolve 592 IR bright stars reaching over 1 magnitude below the Tip of the Red Giant Branch. Significantly deeper optical (F475W and F814W) Hubble Space Telescope images of the same field contain over 2500 stars, reaching to the Red Clump and the Main Sequence turn-off for 0.5 Gyr old populations. Compared to the optical color magnitude diagram (CMD), the near-IR CMD shows significantly tighter AGB sequences, providing a good probe of the intermediate age (0.5 - 5 Gyr) populations. We match observed CMDs with stellar evolution models to recover the SFH of KKH 98. On average, the galaxy has experienced relatively constant low-level star formation (5 x 10^-4 Mo yr^-1) for much of cosmic time. Except for the youngest main sequence populations (age &...

  18. Longitudinal study of mandibular behavior in Class I subjects with vertical and horizontal growth

    Directory of Open Access Journals (Sweden)

    Dirceu Barnabé Raveli

    2012-12-01

    Full Text Available OBJECTIVE: To evaluate possible differences in mandibular behavior in Class I individuals with vertical and horizontal growth patterns. METHODS: The sample consisted of 20 untreated Class I individuals divided into: Group 1 comprising 10 individuals with vertical growth pattern and Group 2 comprising 10 individuals with horizontal growth pattern, all of them belonging to the Burlington Growth Center files, University of Toronto-Canada, radiographically followed-up at ages 9, 12 and 21. Cephalometric radiographs, determined mean values for a long-term evaluation of mandibular behavior using the following measurements: SNB, Co-GN, SN.GoMe, anterior facial height and posterior facial height. RESULTS: SNB and Co-Gn values were higher in horizontal growth group at all of the ages studied; SN.GoMe measure was significantly lower in horizontal growth group; anterior facial height (AFH showed lower values in individuals with horizontal growth pattern; and posterior facial height (PFH showed lower values in individuals with vertical growth pattern. CONCLUSION: Long-term comparisons of Class I individuals' growth tendencies indicate that there are significant differences between both groups. Mandible showed a trend to clockwise rotation in Group 1. Group 2 showed a trend to brachycephalic facial form, due to the deficit in vertical development with regard to anterior facial height.OBJETIVO: avaliar as possíveis diferenças no comportamento mandibular em indivíduos Classe I com crescimento vertical e horizontal. MÉTODOS: a amostra desse estudo consistiu de 20 indivíduos Classe I não tratados, sendo o grupo 1 composto por 10 indivíduos com padrão de crescimento vertical e o grupo 2 por 10 indivíduos com padrão de crescimento horizontal, pertencentes aos arquivos do Burlington Growth Center, University of Toronto, no Canadá, acompanhados radiograficamente nas idade de 9, 12 e 21 anos. Determinou-se, por meio de telerradiografias cefalométricas, em

  19. Persistence-Based Branch Misprediction Bounds for WCET Analysis

    DEFF Research Database (Denmark)

    Puffitsch, Wolfgang

    Branch prediction is an important feature of pipelined processors to achieve high performance. However, it can lead to overly pessimistic worst-case execution time (WCET) bounds when being modeled too conservatively. This paper presents bounds on the number of branch mispredictions for local...... dynamic branch predictors. To handle interferences between branch instructions we use the notion of persistence, a concept that is also found in cache analyses. The bounds apply to branches in general, not only to branches that close a loop. Furthermore, the bounds can be easily integrated into integer...... linear programming formulations of the WCET problem. An evaluation on a number of benchmarks shows that with these bounds, dynamic branch prediction does not necessarily lead to higher WCET bounds than static prediction schemes....

  20. Bioinformatic detection of horizontally transferred DNA in bacterial genomes

    OpenAIRE

    Langille, Morgan GI; Brinkman, Fiona SL

    2009-01-01

    We highlight a selection of recent research on computational methods and associated challenges surrounding the prediction of bacterial horizontal gene transfer. This research area continues to face controversy, but is becoming more critical as the importance of horizontal gene transfer in medically and ecologically important prokaryotic evolution is further appreciated.

  1. Optimal control methods for vertical and horizontal beam dynamics

    International Nuclear Information System (INIS)

    An application of the Macro Fiber Composite (MFC) actuators for damping of a composite beam is presented in this paper. The effectiveness of vibration reduction by a selected control method is tested for vertical and horizontal position of the beam. The original model has been studied numerically by using Galerkin's discretisation method. The numerical results for the vertical and horizontal beams are compared.

  2. Stellar Evolution in NGC 6791: Mass Loss on the Red Giant Branch and the Formation of Low Mass White Dwarfs

    OpenAIRE

    Kalirai, Jasonjot S.; Bergeron, P.; Hansen, Brad M. S.; Kelson, Daniel D.; Reitzel, David B.; Rich, R. Michael; Richer, Harvey B.

    2007-01-01

    We present the first detailed study of the properties (temperatures, gravities, and masses) of the NGC 6791 white dwarf population. This unique stellar system is both one of the oldest (8 Gyr) and most metal-rich ([Fe/H] ~ 0.4) open clusters in our Galaxy, and has a color-magnitude diagram (CMD) that exhibits both a red giant clump and a much hotter extreme horizontal branch. Fitting the Balmer lines of the white dwarfs in the cluster, using Keck/LRIS spectra, suggests that most of these star...

  3. Faster Algorithms on Branch and Clique Decompositions

    Science.gov (United States)

    Bodlaender, Hans L.; van Leeuwen, Erik Jan; van Rooij, Johan M. M.; Vatshelle, Martin

    We combine two techniques recently introduced to obtain faster dynamic programming algorithms for optimization problems on graph decompositions. The unification of generalized fast subset convolution and fast matrix multiplication yields significant improvements to the running time of previous algorithms for several optimization problems. As an example, we give an O^{*}(3^{ω/2k}) time algorithm for Minimum Dominating Set on graphs of branchwidth k, improving on the previous O *(4 k ) algorithm. Here ω is the exponent in the running time of the best matrix multiplication algorithm (currently ωgraphs of cliquewidth k, we improve from O *(8 k ) to O *(4 k ). We also obtain an algorithm for counting the number of perfect matchings of a graph, given a branch decomposition of width k, that runs in time O^{*}(2^{ω/2k}). Generalizing these approaches, we obtain faster algorithms for all so-called [ρ,σ]-domination problems on branch decompositions if ρ and σ are finite or cofinite. The algorithms presented in this paper either attain or are very close to natural lower bounds for these problems.

  4. Synthesis of branched naphthoquinones from castor oil

    Directory of Open Access Journals (Sweden)

    Adriano Olímpio da Silva

    2012-06-01

    Full Text Available The naphthoquinones are cyclic aromatic α,β-dienonas with a basic framework derived from naphthalene. They are also found in many higher plants, algae, fungi and as the product of the  metabolism  of some  bacteria  having large biologica activity described in the literature such as antibacterial, anti-inflammatory, antitumor, anticancer and trypanocidal [1-3]. Castor oil is an abundant raw material in Brazil of great versatility and, it is present in biodiesel production, surfactants, cosmetics and others. Considering the importance of naphthoquinones and, the availability of the ricinoleic acid from castor oil, the aim of this study was the preparation of new branched naphthoquinones in order to test their trypanocidal activity. Castor oil was submitted to saponification with sodium hydroxide, ethanol and water under reflux for 6 h. We then carried out an acid hydrolysis with hydrochloric acid and the formed ricinoleic acid was extracted with ethyl acetate. Following, through Kochi-Anderson addition reaction it was performed the alkylation of a naphthoquinone 1 and 2, using ammonium persulfate, silver nitrate, acetonitrile and water, under heating at 70-80 ° C during 3 h, to give the branched naphthoquinones 4 and 5 (scheme 1. The naphthoquinone 3 will be similarly submitted to this procedure. The naphthoquinones 4 and 5 were purified by column chromatography on sílica gel using hexane as the eluent. The compounds were characterized by mass spectrometry and 1H and 13CNMR spectroscopy.

  5. Benefits of a horizontal well in sandstone waterflood

    International Nuclear Information System (INIS)

    This is a case study which describes the planning and results of a horizontal well in a shallow Wilcox sandstone waterflood unit in central Louisiana. The Tremont H-13-1 was OXY USA Inc.'s first horizontal well. Analysis will include examination of the selection criteria, planning, execution, completion, and production. A variety of well and field data is presented and reviewed to access the value of this information as it applies towards other applications. The Cruse Waterflood Unit is a 2100 ft. Wilcox formation in central Louisiana. Production improvements have been 500% or greater for the horizontal well versus adjacent vertical wells. The horizontal well paid out in less than 4 months Results from this well indicate that not only was this project an economic success, but that other fields will similar conditions can be produced in a more profitable manner with horizontal wells

  6. Cravity modulation of the moss Tortula modica branching

    Science.gov (United States)

    Khorkavtsiv, Yaroslava; Kit, Nadja

    Among various abiotic factors the sensor system of plants constantly perceives light and gravitation impulses and reacts on their action by photo- and gravitropisms. Tropisms play fundamental part in ontogenesis and determination of plant forms. Essentially important question is how light initiating phototropic bending modulates gravitropism. In contrast to flower plants, red light is phototropically active for mosses, and phytochromic system controls initiation of apical growth, branching and photomorphogenesis of mosses. The aim of this investigation was to analyse cell branching of protonemata Tortula modica Zander depending on the direction of light and gravitation vector. The influence of light and gravitation on the form of protonemal turf T. modica, branching and the angle of lateral branches relative to axis of mother cell growth has been investigated. As moss protonemata is not branched in the darkness, light is necessary for branching activation. Minimally low intensity of the red light (0.2 mmol (.) m (-2) ({) .}sec (-1) ) induced branching without visual display of phototropic growth. It has been established that unidirectional action of light and gravitation intensifies branching, and, on the contrary, perpendicularly oriented vectors of factors weaken branches formation. Besides, parallel oriented vectors initiated branching from both cell sides, but oppositely directed vectors initiated branching only from one side. Clinostate rotation the change of the vector gravity and causes uniform cell branching, hence, light and gravitation mutually influence the branching system form of the protonemata cell. It has been shown that the angle of lateral branches in darkness does not depend on the direction of light and gravitation action. After lighting the local growth of the cell wall took place mainly under the angle 90 (o) to the axes of mother cell growth. Then the angle gradually decreased and in 3-4 cell divisions the lateral branch grew under the angle

  7. Zero Discharge Water Management for Horizontal Shale Gas Well Development

    Energy Technology Data Exchange (ETDEWEB)

    Paul Ziemkiewicz; Jennifer Hause; Raymond Lovett; David Locke Harry Johnson; Doug Patchen

    2012-03-31

    Hydraulic fracturing technology (fracking), coupled with horizontal drilling, has facilitated exploitation of huge natural gas (gas) reserves in the Devonian-age Marcellus Shale Formation (Marcellus) of the Appalachian Basin. The most-efficient technique for stimulating Marcellus gas production involves hydraulic fracturing (injection of a water-based fluid and sand mixture) along a horizontal well bore to create a series of hydraulic fractures in the Marcellus. The hydraulic fractures free the shale-trapped gas, allowing it to flow to the well bore where it is conveyed to pipelines for transport and distribution. The hydraulic fracturing process has two significant effects on the local environment. First, water withdrawals from local sources compete with the water requirements of ecosystems, domestic and recreational users, and/or agricultural and industrial uses. Second, when the injection phase is over, 10 to 30% of the injected water returns to the surface. This water consists of flowback, which occurs between the completion of fracturing and gas production, and produced water, which occurs during gas production. Collectively referred to as returned frac water (RFW), it is highly saline with varying amounts of organic contamination. It can be disposed of, either by injection into an approved underground injection well, or treated to remove contaminants so that the water meets the requirements of either surface release or recycle use. Depending on the characteristics of the RFW and the availability of satisfactory disposal alternatives, disposal can impose serious costs to the operator. In any case, large quantities of water must be transported to and from well locations, contributing to wear and tear on local roadways that were not designed to handle the heavy loads and increased traffic. The search for a way to mitigate the situation and improve the overall efficiency of shale gas production suggested a treatment method that would allow RFW to be used as make

  8. Experimental Study on Natural Convection Heat Transfer From two Parallel Horizontal Cylinders in Horizontal Cylindrical Enclosure

    Directory of Open Access Journals (Sweden)

    Ahmed T. Ahmed

    2013-05-01

    Full Text Available  An experimental study on natural convection heat transfer from two parallel horizontal cylinders in horizontal cylindrical enclosure was carried out under condition of constant surfaces temperature for two cylinders and cylindrical enclosure. The study included the effect of Rayleigh number, rotation angle that represent the confined angle between the passing horizontal plane in cylindrical enclosure center and passing line in two cylinders centers, and the spaces between two cylinders on their heat loss ability.39An experimental set-up was used for this purpose which consist watercontainer, test section which is formed of plastic cylinder that represent the cylindrical enclosure, and two heating elements which are formed of two copper cylinders with (19 mm in diameters heated internally by electrical sources that represents transfer and heat loss elements through this set-up.      The experiments were done at the range of Rayleigh number between ( , cylinders rotation angle at ( , and spacing ratio at ( .     The study showed that the ability of heat loss from two cylinders is a function of Rayleigh number, cylinders rotation angle, and the spaces between them. This ability is increased by increasing of Rayleigh number and it was showed that this ability reaches maximum value at the first cylinder ( and minimum value at the second cylinder ( at spacing ratio (S/D=3 and rotation angle ( for the first and ( for the second cylinder respectively.      The effective variables on natural convection heat transfer from the above two cylinders are related by two correlating equations, each one explains dimensionless relation of heat transfer from each cylinder that represented by Nusselt number against Rayleigh number, rotation angle, and the spacing ratio between two cylinders. 

  9. Effect of Horizontal Vibration on the Interfacial Instability in a Horizontal Hele-Shaw Cell

    Directory of Open Access Journals (Sweden)

    Souhar M.

    2012-07-01

    Full Text Available The effect of periodic oscillations on the interfacial instability of two immiscible fluids, confined in a horizontal Hele-Shaw cell, is investigated. A linear stability analysis of the basic state leads to a periodic Mathieu oscillator corresponding to the amplitude of the interface. Then, the threshold of parametric instability of the interface is characterized by harmonic or subharmonic periodic solutions. We show that the relevant parameters that control the interface are the Bond number, density ratio, Weber number and amplitude and frequency of oscillations.

  10. Computing real zeros of a polynomial by branch and bound and branch and reduce algorithms

    Directory of Open Access Journals (Sweden)

    Le Thi Hoai An

    2014-01-01

    Full Text Available In this paper we propose two algorithms based on branch and bound method and reduced interval techniques to compute all real zeros of a polynomial. Quadratic bounding functions are proposed which are better than the well known linear underestimator. Experimental result shows the efficiency of the two algorithms when facing ill-conditioned polynomials.

  11. Horizontal oil well applications and oil recovery assessment. Volume 1: Success of horizontal well technology, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Deskins, W.G.; McDonald, W.J.; Knoll, R.G.; Springer, S.J.

    1995-03-01

    Horizontal technology has been applied in over 110 formations in the USA. Volume I of this study addresses the overall success of horizontal technology, especially in less-publicized formations, i.e., other than the Austin Chalk, Bakken, and Niobrara. Operators in the USA. and Canada were surveyed on a formation-by-formation basis by means of a questionnaire. Response data were received describing horizontal well projects in 58 formations in the USA. and 88 in Canada. Operators responses were analyzed for trends in technical and economic success based on lithology (clastics and carbonates) and resource type (light oil, heavy oil, and gas). The potential impact of horizontal technology on reserves was also estimated. A forecast of horizontal drilling activity over the next decade was developed.

  12. Quantification of branching in model three-arm star polyethylene

    KAUST Repository

    Ramachandran, Ramnath

    2012-01-24

    The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

  13. Shear horizontal wave excitation and reception with shear horizontal piezoelectric wafer active sensor (SH-PWAS)

    International Nuclear Information System (INIS)

    This article discusses shear horizontal (SH) guided-waves that can be excited with shear type piezoelectric wafer active sensor (SH-PWAS). The paper starts with a review of state of the art SH waves modelling and their importance in non-destructive evaluation (NDE) and structural health monitoring (SHM). The basic piezoelectric sensing and actuation equations for the case of shear horizontal piezoelectric wafer active sensor (SH-PWAS) with electro-mechanical coupling coefficient d35 are reviewed. Multiphysics finite element modelling (MP-FEM) was performed on a free SH-PWAS to show its resonance modeshapes. The actuation mechanism of the SH-PWAS is predicted by MP-FEM, and modeshapes of excited structure are presented. The structural resonances are compared with experimental measurements and showed good agreement. Analytical prediction of SH waves was performed. SH wave propagation experimental study was conducted between different combinations of SH-PWAS and regular in-plane PWAS transducers. Experimental results were compared with analytical predictions for aluminium plates and showed good agreement. 2D wave propagation effects were studied by MP-FEM. An analytical model was developed for SH wave power and energy. The normal mode expansion (NME) method was used to account for superpositioning multimodal SH waves. Modal participation factors were presented to show the contribution of every mode. Power and energy transfer between SH-PWAS and the structure was analyzed. Finally, we present simulations of our developed wave power and energy analytical models. (paper)

  14. Computational studies of horizontal axis wind turbines

    Science.gov (United States)

    Xu, Guanpeng

    A numerical technique has been developed for efficiently simulating fully three-dimensional viscous fluid flow around horizontal axis wind turbines (HAWT) using a zonal approach. The flow field is viewed as a combination of viscous regions, inviscid regions and vortices. The method solves the costly unsteady Reynolds averaged Navier-Stokes (RANS) equations only in the viscous region around the turbine blades. It solves the full potential equation in the inviscid region where flow is irrotational and isentropic. The tip vortices are simulated using a Lagrangean approach, thus removing the need to accurately resolve them on a fine grid. The hybrid method is shown to provide good results with modest CPU resources. A full Navier-Stokes based methodology has also been developed for modeling wind turbines at high wind conditions where extensive stall may occur. An overset grid based version that can model rotor-tower interactions has been developed. Finally, a blade element theory based methodology has been developed for the purpose of developing improved tip loss models and stall delay models. The effects of turbulence are simulated using a zero equation eddy viscosity model, or a one equation Spalart-Allmaras model. Two transition models, one based on the Eppler's criterion, and the other based on Michel's criterion, have been developed and tested. The hybrid method has been extensively validated for axial wind conditions for three rotors---NREL Phase II, Phase III, and Phase VI configurations. A limited set of calculations has been done for rotors operating under yaw conditions. Preliminary simulations have also been carried out to assess the effects of the tower wake on the rotor. In most of these cases, satisfactory agreement has been obtained with measurements. Using the numerical results from present methodologies as a guide, Prandtl's tip loss model and Corrigan's stall delay model were correlated with present calculations. An improved tip loss model has been

  15. Gauge Theories on the Coulomb branch

    CERN Document Server

    Schwarz, John H

    2014-01-01

    We construct the world-volume action of a probe D3-brane in $AdS_5 \\times S^5$ with $N$ units of flux. It has the field content, symmetries, and dualities of the $U(1)$ factor of ${\\cal N} =4$ $U(N+1)$ super Yang--Mills theory, spontaneously broken to $U(N) \\times U(1)$ by being on the Coulomb branch, with the massive fields integrated out. This motivates the conjecture that it is the exact effective action, called a `highly effective action' (HEA). We construct an $SL(2,Z)$ multiplet of BPS soliton solutions of the D3-brane theory (the conjectured HEA) and show that it reproduces the electrically charged massive states that have been integrated out as well as magnetic monopoles and dyons. Their charges are uniformly spread on a spherical surface, called a `soliton bubble', which is interpreted as a phase boundary.

  16. Introduction to Asymptotic Giant Branch Stars

    Science.gov (United States)

    El Eid, Mounib F.

    2016-04-01

    A brief introduction on the main characteristics of the asymptotic giant branch stars (briefly: AGB) is presented. We describe a link to observations and outline basic features of theoretical modeling of these important evolutionary phases of stars. The most important aspects of the AGB stars is not only because they are the progenitors of white dwarfs, but also they represent the site of almost half of the heavy element formation beyond iron in the galaxy. These elements and their isotopes are produced by the s-process nucleosynthesis, which is a neutron capture process competing with the β- radioactive decay. The neutron source is mainly due to the reaction 13C(α,n)16O reaction. It is still a challenging problem to obtain the right amount of 13 C that can lead to s-process abundances compatible with observation. Some ideas are presented in this context.

  17. Simple statistical model for branched aggregates

    DEFF Research Database (Denmark)

    Lemarchand, Claire; Hansen, Jesper Schmidt

    2015-01-01

    We propose a statistical model that can reproduce the size distribution of any branched aggregate, including amylopectin, dendrimers, molecular clusters of monoalcohols, and asphaltene nanoaggregates. It is based on the conditional probability for one molecule to form a new bond with a molecule......, given that it already has bonds with others. The model is applied here to asphaltene nanoaggregates observed in molecular dynamics simulations of Cooee bitumen. The variation with temperature of the probabilities deduced from this model is discussed in terms of statistical mechanics arguments. The...... relevance of the statistical model in the case of asphaltene nanoaggregates is checked by comparing the predicted value of the probability for one molecule to have exactly i bonds with the same probability directly measured in the molecular dynamics simulations. The agreement is satisfactory...

  18. Branching process in a stochastic extremal model

    Science.gov (United States)

    Manna, S. S.

    2009-08-01

    We considered a stochastic version of the Bak-Sneppen model (SBSM) of ecological evolution where the number M of sites mutated in a mutation event is restricted to only two. Here the mutation zone consists of only one site and this site is randomly selected from the neighboring sites at every mutation event in an annealed fashion. The critical behavior of the SBSM is found to be the same as the BS model in dimensions d=1 and 2. However on the scale-free graphs the critical fitness value is nonzero even in the thermodynamic limit but the critical behavior is mean-field like. Finally ⟨M⟩ has been made even smaller than two by probabilistically updating the mutation zone, which also shows the original BS model behavior. We conjecture that a SBSM on any arbitrary graph with any small branching factor greater than unity will lead to a self-organized critical state.

  19. Basic Sciences Branch annual report, FY 1990

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-01

    This report summarizes the progress of the Basic Sciences Branch of the National Renewable Energy Laboratory (NREL) from October 1, 1989, through September 30, 1990. Six technical sections of the report cover these main areas of NREL`s in-house research: Semiconductor Crystal Growth, Amorphous Silicon Research, Polycrystalline Thin Films, III-V High-Efficiency Photovoltaic Cells, Solid-State Theory, and Solid-State Spectroscopy. Each section of the report was written by the group leader principally in charge of the work. The task in each case was to explain the purpose and major accomplishments of the work in the context of the US Department of Energy`s National Photovoltaic Research Program plans.

  20. Flight Dynamics Analysis Branch 2005 Technical Highlights

    Science.gov (United States)

    2005-01-01

    This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2005. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based); spacecraft trajectory design and maneuver planning; attitude analysis; attitude determination and sensor calibration; and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.

  1. Unquenched flavor on the Higgs branch

    CERN Document Server

    Faedo, Anton F; Pantelidou, Christiana; Tarrio, Javier

    2016-01-01

    We construct the gravity duals of the Higgs branches of three-dimensional (four-dimensional) super Yang-Mills theories coupled to $N_\\textrm{f}$ quark flavors. The effect of the quarks on the color degrees of freedom is included, and corresponds on the gravity side to the backreaction of $N_\\textrm{f}$ flavor D6-branes (D7-branes) on the background of $N_\\textrm{c}$ color D2-branes (D3-branes). The Higgsing of the gauge group arises from the dissolution of some color branes inside the flavor branes. The dissolved color branes are represented by non-Abelian instantons whose backreaction is also included. The result is a cascading-like solution in which the effective number of color branes varies along the holographic direction. In the three-dimensional case the solution may include an arbitrary number of quasi-conformal (walking) regions.

  2. Cold holographic matter in the Higgs branch

    Science.gov (United States)

    Itsios, Georgios; Jokela, Niko; Ramallo, Alfonso V.

    2015-07-01

    We study collective excitations of cold (2 + 1)-dimensional fundamental matter living on a defect of the four-dimensional N = 4 super Yang-Mills theory in the Higgs branch. This system is realized holographically as a D3-D5 brane intersection, in which the D5-brane is treated as a probe with a non-zero gauge flux across the internal part of its worldvolume. We study the holographic zero sound mode in the collisionless regime at low temperature and find a simple analytic result for its dispersion relation. We also find the diffusion constant of the system in the hydrodynamic regime at higher temperature. In both cases we study the dependence on the flux parameter which determines the amount of Higgs symmetry breaking. We also discuss the anyonization of this construction.

  3. Cold holographic matter in the Higgs branch

    CERN Document Server

    Itsios, Georgios; Ramallo, Alfonso V

    2015-01-01

    We study collective excitations of cold (2+1)-dimensional fundamental matter living on a defect of the four-dimensional N=4 super Yang-Mills theory in the Higgs branch. This system is realized holographically as a D3-D5 brane intersection, in which the D5-brane is treated as a probe with a non-zero gauge flux across the internal part of its worldvolume. We study the holographic zero sound mode in the collisionless regime at low temperature and find a simple analytic result for its dispersion relation. We also find the diffusion constant of the system in the hydrodynamic regime at higher temperature. In both cases we study the dependence on the flux parameter which determines the amount of Higgs symmetry breaking. We also discuss the anyonization of this construction.

  4. Cold holographic matter in the Higgs branch

    Directory of Open Access Journals (Sweden)

    Georgios Itsios

    2015-07-01

    Full Text Available We study collective excitations of cold (2+1-dimensional fundamental matter living on a defect of the four-dimensional N=4 super Yang–Mills theory in the Higgs branch. This system is realized holographically as a D3–D5 brane intersection, in which the D5-brane is treated as a probe with a non-zero gauge flux across the internal part of its worldvolume. We study the holographic zero sound mode in the collisionless regime at low temperature and find a simple analytic result for its dispersion relation. We also find the diffusion constant of the system in the hydrodynamic regime at higher temperature. In both cases we study the dependence on the flux parameter which determines the amount of Higgs symmetry breaking. We also discuss the anyonization of this construction.

  5. Command and Data Handling Branch Internship

    Science.gov (United States)

    Billings, Rachel Mae

    2016-01-01

    Modular Integrated Stackable Layers (MISL) is a computer system designed for simple, fast, and cost effective flexible reconfiguration in space environments such as the ISS and Orion projects for various uses. Existing applications include wireless and wired communications, data acquisition and instrumentation, and camera systems, and potential applications include bus protocol converters and subsystem control. MISL is based on Texas Instruments (TI)' MSP430 16-bit ultra-low-power microcontroller device. The purpose of my project was to integrate the MISL system with a liquid crystal display (LCD) touchscreen. The LCD, manufactured by Crystalfontz and part number CFAF320240F-035T-TS, is a 320 by 240 RGB resistive color screen including an optional carrier board. The vast majority of the project was done with Altium Designer, a tool for printed circuit board (PCB) schematic capture, 3D design, and FPGA (Field Programmable Gate Array) development. The new PCB was to allow the LCD to directly stack to the rest of MISL. Research was done with datasheets for the TI microcontroller and touchscreen display in order to meet desired hardware specifications. Documentation on prior MISL projects was also utilized. The initial step was to create a schematic for the LCD, power bus, and data bus connections between components. A layout was then designed with the required physical dimensions, routed traces and vias, power and ground planes, layer stacks, and other specified design rules such as plane clearance and hole size. Multiple consultation sessions were held with Hester Yim, the technical discipline lead for the Command and Data Handling Branch, and Christy Herring, the lead PCB layout designer in the Electronic Design and Manufacturing Branch in order to ensure proper configuration. At the moment, the PCB is awaiting revision by the latter-mentioned branch. Afterwards, the board will begin to undergo the manufacturing and testing process. Throughout the internship at

  6. Accounting for horizontal gene transfers explains conflicting hypotheses regarding the position of aquificales in the phylogeny of Bacteria

    Directory of Open Access Journals (Sweden)

    Gouy Manolo

    2008-10-01

    Full Text Available Abstract Background Despite a large agreement between ribosomal RNA and concatenated protein phylogenies, the phylogenetic tree of the bacterial domain remains uncertain in its deepest nodes. For instance, the position of the hyperthermophilic Aquificales is debated, as their commonly observed position close to Thermotogales may proceed from horizontal gene transfers, long branch attraction or compositional biases, and may not represent vertical descent. Indeed, another view, based on the analysis of rare genomic changes, places Aquificales close to epsilon-Proteobacteria. Results To get a whole genome view of Aquifex relationships, all trees containing sequences from Aquifex in the HOGENOM database were surveyed. This study revealed that Aquifex is most often found as a neighbour to Thermotogales. Moreover, informational genes, which appeared to be less often transferred to the Aquifex lineage than non-informational genes, most often placed Aquificales close to Thermotogales. To ensure these results did not come from long branch attraction or compositional artefacts, a subset of carefully chosen proteins from a wide range of bacterial species was selected for further scrutiny. Among these genes, two phylogenetic hypotheses were found to be significantly more likely than the others: the most likely hypothesis placed Aquificales as a neighbour to Thermotogales, and the second one with epsilon-Proteobacteria. We characterized the genes that supported each of these two hypotheses, and found that differences in rates of evolution or in amino-acid compositions could not explain the presence of two incongruent phylogenetic signals in the alignment. Instead, evidence for a large Horizontal Gene Transfer between Aquificales and epsilon-Proteobacteria was found. Conclusion Methods based on concatenated informational proteins and methods based on character cladistics led to different conclusions regarding the position of Aquificales because this lineage

  7. Oscillation and CP wiolation in the ''horizontal'' superweak gauge scheme

    International Nuclear Information System (INIS)

    A model, in framework of which the CP violation processes and K0 - anti K0, D0 - anti D0... mixing are caused by ''horizontal'' gauge weak interactions is considered. Spontaneous CP violation is provided by introducing the Higgs multiplets belonging to adjoint representation of the SUsup(H)(2)sub(L(R)) group. Possible contributions of the ''horizontal'' interactions into the values of mixing and CP violation parameters are calculated. It is emphasized that the effective strength of ''up''-''down'' symmetry breaking by the ''horizontal'' interactions is less than by the standard weak interactions

  8. A Study of Horizontal Displacement of Laterally Loaded Piles

    Directory of Open Access Journals (Sweden)

    Aram M. Raheem

    2013-05-01

    Full Text Available  A theoretical approach is used to analyze single pile and pile in group under lateral loading using two programs. The first one used the finite element method for single pile depending on plain strain condition while the second one used the characteristic load method for pile in group. Horizontal displacement for pile in group is measured while both horizontal displacement and shear stress for single pile are measured. A comparison between the results of horizontal displacement for both single pile and pile in group with the actual practical values are produced and shows a good agreement.

  9. Method of positioning tubing within a horizontal well

    International Nuclear Information System (INIS)

    This patent describes a method of variably and selectively positioning coil tubing in a horizontally drilled well having a generally vertical section, a curve section and a generally horizontal section. It comprises securing a generally hollow tubing guide shoe to one end of a tubing string; inserting the tubing guide shoe and a portion of the tubing string through the generally vertical section and the curve section and into a portion of the generally horizontal section; and inserting coil tubing through the tubing string

  10. Formation of chiral branched nanowires by the Eshelby Twist.

    Science.gov (United States)

    Zhu, Jia; Peng, Hailin; Marshall, A F; Barnett, D M; Nix, W D; Cui, Yi

    2008-08-01

    Manipulating the morphology of inorganic nanostructures, such as their chirality and branching structure, has been actively pursued as a means of controlling their electrical, optical and mechanical properties. Notable examples of chiral inorganic nanostructures include carbon nanotubes, gold multishell nanowires, mesoporous nanowires and helical nanowires. Branched nanostructures have also been studied and been shown to have interesting properties for energy harvesting and nanoelectronics. Combining both chiral and branching motifs into nanostructures might provide new materials properties. Here we show a chiral branched PbSe nanowire structure, which is formed by a vapour-liquid-solid branching from a central nanowire with an axial screw dislocation. The chirality is caused by the elastic strain of the axial screw dislocation, which produces a corresponding Eshelby Twist in the nanowires. In addition to opening up new opportunities for tailoring the properties of nanomaterials, these chiral branched nanowires also provide a direct visualization of the Eshelby Twist. PMID:18685634

  11. Branched projective structures with quasi-Fuchsian holonomy

    CERN Document Server

    Calsamiglia, Gabriel; Francaviglia, Stefano

    2012-01-01

    We prove that if S is a closed compact surface of negative Euler characteristic, and if R is a quasi-Fuchsian representation in PSL(2,C), then the deformation space M(k,R) of branched projective structures on S with total branching order k and holonomy R is connected, as soon as k>0. Equivalently, two branched projective structures with the same quasi-Fuchsian holonomy and the same number of branch points are related by a movement of branch points. In particular grafting annuli are obtained by moving branch points. In the appendix we give an explicit atlas for the space M(k,R). It is shown to be a smooth complex manifold modeled on Hurwitz spaces.

  12. Deregulation of Bank Entry and Branching: Impact on Competition

    OpenAIRE

    Milo, Melanie S.

    2001-01-01

    This paper looks at public policy towards bank entry and branching in the Philippines and its impact on the sector’s structure, conduct and performance. In particular, it argues that regulatory restrictions on bank entry and branching have had adverse effects on competition, while the liberalization of these restrictions have led to a more competitive banking sector. The paper has two main sections. Section II presents the history of regulation of bank entry and branching in the Philippines. ...

  13. Interaction forces between surfaces coated with highly branched polyelectrolytes

    OpenAIRE

    Pericet-Cámara, Ramón; Borkovec, Michal

    2007-01-01

    In this thesis, interactions between surfaces with adsorbed highly branched polyelectrolytes were studied with the colloidal probe technique. By studying the adsorption behavior of highly branched polyelectrolytes, the lateral distribution of the surface charge could be tuned by the appropriate adsorption conditions. By choosing different polyelecrtrolytes, namely highly branched poly(ethylenimine) (PEI) and poly(amido amine) (PAMAM) dendrimers, it was possible to investigate the forces betwe...

  14. Interaction forces between surfaces coated with highly branched polyelectrolytes

    OpenAIRE

    Pericet-Cámara, Ramón

    2006-01-01

    In this thesis, interactions between surfaces with adsorbed highly branched polyelectrolytes were studied with the colloidal probe technique. By studying the adsorption behavior of highly branched polyelectrolytes, the lateral distribution of the surface charge could be tuned by the appropriate adsorption conditions. By choosing different polyelecrtrolytes, namely highly branched poly(ethylenimine) (PEI) and poly(amido amine) (PAMAM) dendrimers, it was possible to investigate the forces betwe...

  15. Pressure Change in Tee Branch Pipe in Oscillatory Flow

    OpenAIRE

    Daisuke Sakamoto; Chongho Youn; Toshiharu Kagawa

    2013-01-01

    The purpose of this paper is to contribute to the understanding of unsteady flow of branch pipes in pneumatic systems. Branch pipes are used in pneumatic pipe systems in various industrial fields. To predict the unsteady pressure changes in the pneumatic piping systems, it is necessary that the dynamic characteristics of branch pipes are at hand, in addition to the dynamic characteristic of single pipe. However, while so many studies are accumulated for a single pipe dynamics, few studies hav...

  16. Human vagus nerve branching in the cervical region.

    Directory of Open Access Journals (Sweden)

    Niels Hammer

    Full Text Available Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects. However, vagus nerve branching has not yet been described in the context of vagus nerve stimulation.Branching of the cervical vagus nerve was investigated macroscopically in 35 body donors (66 cervical sides in the carotid sheath. After X-ray imaging for determining the vertebral levels of cervical vagus nerve branching, samples were removed to confirm histologically the nerve and to calculate cervical vagus nerve diameters and cross-sections.Cervical vagus nerve branching was observed in 29% of all cases (26% unilaterally, 3% bilaterally and proven histologically in all cases. Right-sided branching (22% was more common than left-sided branching (12% and occurred on the level of the fourth and fifth vertebra on the left and on the level of the second to fifth vertebra on the right side. Vagus nerves without branching were significantly larger than vagus nerves with branches, concerning their diameters (4.79 mm vs. 3.78 mm and cross-sections (7.24 mm2 vs. 5.28 mm2.Cervical vagus nerve branching is considerably more frequent than described previously. The side-dependent differences of vagus nerve branching may be linked to the asymmetric effects of the vagus nerve. Cervical vagus nerve branching should be taken into account when identifying main trunk of the vagus nerve for implanting electrodes to minimize potential side effects or lacking therapeutic benefits of vagus nerve stimulation.

  17. Branch points of substitutions and closing ordered Bratteli diagrams

    CERN Document Server

    Yassawi, Reem

    2011-01-01

    We study stationary ordered Bratteli diagrams and give necessary and sufficient conditions for these orders to generate a continuous Vershik map. We apply this to finding adic representations for one sided substitution subshifts. We give an algorithm to find the branch points of a substitution, which have to be mapped to the minimal elements of such an ordering. We find adic representations for substitutions with one branch point, and also substitutions all of whose branch points are fixed.

  18. Parallel Branch and Bound on a CPU-GPU System

    OpenAIRE

    Boukedjar, Abdelamine; Lalami, Mohamed Esseghir; El-Baz, Didier

    2012-01-01

    Hybrid implementation via CUDA of a branch and bound method for knapsack problems is proposed. Branch and bound computations can be carried out either on the CPU or on the GPU according to the size of the branch and bound list, i.e. the number of nodes. Tests are carried out on a Tesla C2050 GPU. A first series of computational results showing a substantial speedup is displayed and analyzed.

  19. The Branching of Graphs in 2-d Quantum Gravity

    OpenAIRE

    Harris, M. G.

    1996-01-01

    The branching ratio is calculated for three different models of 2d gravity, using dynamical planar phi-cubed graphs. These models are pure gravity, the D=-2 Gaussian model coupled to gravity and the single spin Ising model coupled to gravity. The ratio gives a measure of how branched the graphs dominating the partition function are. Hence it can be used to estimate the location of the branched polymer phase for the multiple Ising model coupled to 2d gravity.

  20. Exponential decay of Laplacian eigenfunctions in domains with branches

    CERN Document Server

    Delitsyn, Andrey; Grebenkov, Denis S

    2011-01-01

    The behavior of Laplacian eigenfunctions in domains with branches is investigated. If an eigenvalue is below a threshold which is determined by the shape of the branch, the associated eigenfunction is proved to exponentially decay inside the branch. The decay rate is twice the square root of the difference between the threshold and the eigenvalue. The derived exponential estimate is applicable for arbitrary domains in any spatial dimension. Numerical simulations illustrate and further extend the theoretical estimate.

  1. Exponential decay of Laplacian eigenfunctions in domains with branches

    OpenAIRE

    Delitsyn, Andrey; Nguyen, Binh-Thanh; Grebenkov, Denis S.

    2011-01-01

    The behavior of Laplacian eigenfunctions in domains with branches is investigated. If an eigenvalue is below a threshold which is determined by the shape of the branch, the associated eigenfunction is proved to exponentially decay inside the branch. The decay rate is twice the square root of the difference between the threshold and the eigenvalue. The derived exponential estimate is applicable for arbitrary domains in any spatial dimension. Numerical simulations illustrate and further extend ...

  2. An object oriented approach to generic branch and bound

    OpenAIRE

    Bruin, Arie; Kindervater, Gerard; Trienekens, H.W.J.M.; Goot, R.A.

    1996-01-01

    textabstractBranch and bound algorithms can be characterized by a small set of basic rules that are applied in a divide-and-conquer-like framework. The framework is about the same in all applications, whereas the specification of the rules is problem dependent. Building a framework is a rather simple task in sequential implementations, but must not be underestimated in the parallel case, especially if an efficient branch and bound algorithm is required. In generic branch and bound models, the...

  3. Towards an abstract parallel branch and bound machine

    OpenAIRE

    Bruin, Arie; Kindervater, Gerard; Trienekens, H.W.J.M.

    1995-01-01

    textabstractMany (parallel) branch and bound algorithms look very different from each other at first glance. They exploit, however, the same underlying computational model. This phenomenon can be used to define branch and bound algorithms in terms of a set of basic rules that are applied in a specific (predefined) order. In the sequential case, the specification of Mitten's rules turns out to be sufficient for the development of branch and bound algorithms. In the parallel case, the situation...

  4. Distribution Network Planning and Design Using Branch and Bound Methods

    OpenAIRE

    Jalal Abdallah

    2005-01-01

    This study presents implementation of the bound and branch methods as an optimization mathematical device for distribution network planning. A development technology concentrates on minimizing the total costs and provides extended opportunities for improvement of network operation, from the initial planning stage. The study illustrate the mathematical and the algorithm of the branch and bound method with an example to indicate the efficiency of the branch and bound in plan...

  5. A branch-and-bound methodology within algebraic modelling systems

    OpenAIRE

    Bisschop, J.J.; Heerink, J.B.J.; Kloosterman, G.

    1998-01-01

    Through the use of application-specific branch-and-bound directives it is possible to find solutions to combinatorial models that would otherwise be difficult or impossible to find by just using generic branch-and-bound techniques within the framework of mathematical programming. {\\sc Minto} is an example of a system which offers the possibility to incorporate user-provided directives (written in {\\sc C}) to guide the branch-and-bound search. Its main focus, however, remains on mathematical p...

  6. Penentuan Batas Bawah pada Metode Branch and Price

    OpenAIRE

    Meliana

    2013-01-01

    Integer Programming is a specific linear programming where the variables of decision are integer. There are so many kind of way to finish this integer programming; one of them is Branch and Price method. Like Branch and Bound method, in the step to finish the integer programming in Branch and Price method need the iterations that are too long. To make the iteration to be short then should be given the lower bound.

  7. Solving Multistage Influence Diagrams using Branch-and-Bound Search

    OpenAIRE

    Yuan, Changhe; Wu, Xiaojian; Hansen, Eric A.

    2012-01-01

    A branch-and-bound approach to solving influ- ence diagrams has been previously proposed in the literature, but appears to have never been implemented and evaluated - apparently due to the difficulties of computing effective bounds for the branch-and-bound search. In this paper, we describe how to efficiently compute effective bounds, and we develop a practical implementa- tion of depth-first branch-and-bound search for influence diagram evaluation that outperforms existing methods for solvin...

  8. Metastability of Bose and Fermi gases on the upper branch

    OpenAIRE

    LeClair, Andre; Roditi, Itzhak; Squires, Joshua

    2016-01-01

    We study three dimensional Bose and Fermi gases in the upper branch, a phase defined by the absence of bound states in the repulsive interaction regime, within an approximation that considers only two-body interactions. Employing a formalism based on the S-matrix, we derive a useful analytic expression that holds on the upper branch in the weak coupling limit. We determine upper branch phase diagrams for both bosons and fermions with techniques valid for arbitrary positive scattering length.

  9. University Competition and Transnational Education: The Choice of Branch Campus

    OpenAIRE

    Joanna Poyago-Theotoky; Alessandro Tampieri

    2015-01-01

    We present a theoretical framework in which an elitist and a non- elitist university in a developed country compete by choosing their admission standards and deciding whether or not to open a branch campus in a developing country. Students from a developing country attend university either if a branch campus is opened or if they can afford to move to the developed country. We characterise the equi- libria by focussing on the relationship between the investment costs of a branch campus and the...

  10. Activities of the Development Branch. 1978-1981

    International Nuclear Information System (INIS)

    The activities carried out by the Development Branch from 1978 through 1981 are summarized. Subjects covered include: Metallurgy, Nuclear Fuels, Instrumentation and Control, Nuclear Reactors, as well as the various projects developed during this period and the administrative and technical activities of various groups belonging to this Branch. A list of publications by personnel of this Branch during the same period is also included. (C.A.K.)

  11. Branch structure of corona discharge: experimental simulation and chemical properties

    International Nuclear Information System (INIS)

    The branch structure of corona discharge has been investigated via C2H2 corona discharge. Carbon filament with excellent branch structure is formed in the discharge. This carbon filament offers a direct mimic of the branch structure of corona discharge. It provides a very useful way to study on the average energy, physical and chemical characteristics of corona discharge. On this basis, the chemical property of corona discharge for methane conversion is discussed. (authors)

  12. NGC 362: another globular cluster with a split red giant branch

    CERN Document Server

    Carretta, E; Gratton, R G; Lucatello, S; D'Orazi, V; Bellazzini, M; Catanzaro, G; Leone, F; Momany, Y; Sollima, A

    2013-01-01

    We obtained FLAMES GIRAFFE+UVES spectra for both first and second-generation red giant branch (RGB) stars in the globular cluster (GC) NGC 362 and used them to derive abundances of 21 atomic species for a sample of 92 stars. The surveyed elements include proton-capture (O, Na, Mg, Al, Si), alpha-capture (Ca, Ti), Fe-peak (Sc, V, Mn, Co, Ni, Cu), and neutron-capture elements (Y, Zr, Ba, La, Ce, Nd, Eu, Dy). The analysis is fully consistent with that presented for twenty GCs in previous papers of this series. Stars in NGC 362 seem to be clustered into two discrete groups along the Na-O anti-correlation, with a gap at [O/Na] 0 dex. Na-rich, second generation stars show a trend to be more centrally concentrated, although the level of confidence is not very high. When compared to the classical second-parameter twin NGC 288, with similar metallicity, but different horizontal branch type and much lower total mass, the proton-capture processing in stars of NGC 362 seems to be more extreme, confirming previous analysi...

  13. The normal distribution of thoracoabdominal aorta small branch artery ostia

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the normal distribution of aortic branch artery ostia. CT scans of 100 subjects were retrospectively reviewed. The angular distributions of the aorta with respect to the center of the T3 to L4 vertebral bodies, and of branch artery origins with respect to the center of the aorta were measured. At each vertebral body level the distribution of intercostal/lumbar arteries and other branch arteries were calculated. The proximal descending aorta is posteriorly placed becoming a midline structure, at the thoracolumbar junction, and remains anterior to the vertebral bodies within the abdomen. The intercostal and lumbar artery ostia have a distinct distribution. At each vertebral level from T3 caudally, one intercostal artery originates from the posterior wall of the aorta throughout the thoracic aorta, while the other intercostal artery originates from the medial wall of the descending thoracic aorta high in the chest, posteromedially from the mid-thoracic aorta, and from the posterior wall of the aorta low in the chest. Mediastinal branches of the thoracic aorta originate from the medial and anterior wall. Lumbar branches originate only from the posterior wall of the abdominal aorta. Aortic branch artery origins arise with a bimodal distribution and have a characteristic location. Mediastinal branches of the thoracic aorta originate from the medial and anterior wall. Knowing the location of aortic branch artery ostia may help distinguish branch artery pseudoaneurysms from penetrating ulcers.

  14. China Strengthens Macro-management in Petrochemical Branches

    Institute of Scientific and Technical Information of China (English)

    Xu Hui

    1997-01-01

    @@ China will strengthen macro-management in petrochemical branches in order to reasonably utilize the national petroleum resources and improve its competitive capacity in international refinery industrial market.

  15. [Variability of the celiac artery and its branches in sheep].

    Science.gov (United States)

    Karmona, Kh; Kovachev, G

    1985-01-01

    Contrast matter was used with a total of 363 sheep fetuses, newborn lambs, and adult sheep to study the variability of the coeliac artery and its branches. It was found that the artery and some of its branches, such as arteria ruminalis sinistra, arteria reticularis, and arteria lienalis often showed variations, resp., deviations in their branching and distribution. Others, such as arteria ruminalis dextra and arteria hepatica showed no variations whatever. Both the coeliac artery and the anterior intestinal artery in the sheep were most often shown to branch from the aorta alone (in 71.07 per cent of the cases) as against the rarely observed common truncus coeliacomesentericus (in 28.93 per cent of the cases). The most commonly observed form of branching of arteria coeliaca seemed to be tripus coeliacus, while the branching with the formation of a short truncus hepatogastricus was comparatively a rare phenomenon. It was also established that the left ruminal artery was much more frequently the branch of truncus lienoruminalis than the branch of arteria gastrica sinistra. So far as the place in which arteria reticularis arose three variants were observed. Most frequently this artery was shown to be the branch of arteria gastrica sinistra. PMID:4013078

  16. Experimental Evaluation of Branching Schemes for the CSP

    CERN Document Server

    Balafoutis, Thanasis; Stergiou, Kostas

    2010-01-01

    The search strategy of a CP solver is determined by the variable and value ordering heuristics it employs and by the branching scheme it follows. Although the effects of variable and value ordering heuristics on search effort have been widely studied, the effects of different branching schemes have received less attention. In this paper we study this effect through an experimental evaluation that includes standard branching schemes such as 2-way, d-way, and dichotomic domain splitting, as well as variations of set branching where branching is performed on sets of values. We also propose and evaluate a generic approach to set branching where the partition of a domain into sets is created using the scores assigned to values by a value ordering heuristic, and a clustering algorithm from machine learning. Experimental results demonstrate that although exponential differences between branching schemes, as predicted in theory between 2-way and d-way branching, are not very common, still the choice of branching sche...

  17. Phytoplasma induced free-branching in commercial poinsettia cultivars.

    Science.gov (United States)

    Lee, I M; Klopmeyer, M; Bartoszyk, I M; Gundersen-Rindal, D E; Chou, T S; Thomson, K L; Eisenreich, R

    1997-02-01

    Free-branching poinsettia cultivars that produce numerous axillary shoots are essential for propagating desirable multi-flowered poinsettias (Euphorbia pulcherrima Wild. Klotz). For more than a decade, a biological agent has been suspected to cause free-branching in poinsettias. Attempts to identify the branching agent have failed. Isolation of the pathogen was accomplished using a living host and it was concluded that an unculturable phytoplasma is the cause of free-branching in poinsettias. This is the first reported example of a pathogenic phytoplasma as the causal agent of a desirable and economically important trait. PMID:9035146

  18. Branched RNA: A New Architecture for RNA Interference

    Directory of Open Access Journals (Sweden)

    Anna Aviñó

    2011-01-01

    Full Text Available Branched RNAs with two and four strands were synthesized. These structures were used to obtain branched siRNA. The branched siRNA duplexes had similar inhibitory capacity as those of unmodified siRNA duplexes, as deduced from gene silencing experiments of the TNF-α protein. Branched RNAs are considered novel structures for siRNA technology, and they provide an innovative tool for specific gene inhibition. As the method described here is compatible with most RNA modifications described to date, these compounds may be further functionalized to obtain more potent siRNA derivatives and can be attached to suitable delivery systems.

  19. Distribution Network Planning and Design Using Branch and Bound Methods

    Directory of Open Access Journals (Sweden)

    Jalal Abdallah

    2005-01-01

    Full Text Available This study presents implementation of the bound and branch methods as an optimization mathematical device for distribution network planning. A development technology concentrates on minimizing the total costs and provides extended opportunities for improvement of network operation, from the initial planning stage. The study illustrate the mathematical and the algorithm of the branch and bound method with an example to indicate the efficiency of the branch and bound in planning and design processes. It also shows that the optimal configuration strongly depends on the branching rule and on the bound calculation bases.

  20. Branching and annihilating random walks: exact results at low branching rate.

    Science.gov (United States)

    Benitez, Federico; Wschebor, Nicolás

    2013-05-01

    We present some exact results on the behavior of branching and annihilating random walks, both in the directed percolation and parity conserving universality classes. Contrary to usual perturbation theory, we perform an expansion in the branching rate around the nontrivial pure annihilation (PA) model, whose correlation and response function we compute exactly. With this, the nonuniversal threshold value for having a phase transition in the simplest system belonging to the directed percolation universality class is found to coincide with previous nonperturbative renormalization group (RG) approximate results. We also show that the parity conserving universality class has an unexpected RG fixed point structure, with a PA fixed point which is unstable in all dimensions of physical interest. PMID:23767512