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Sample records for relations spin-down rates

  1. Tidal spin down rates of homogeneous triaxial viscoelastic bodies

    NASA Astrophysics Data System (ADS)

    Quillen, Alice C.; Kueter-Young, Andrea; Frouard, Julien; Ragozzine, Darin

    2016-08-01

    We use numerical simulations to measure the sensitivity of the tidal spin down rate of a homogeneous triaxial ellipsoid to its axis ratios by comparing the drift rate in orbital semi-major axis to that of a spherical body with the same mass, volume and simulated rheology. We use a mass-spring model approximating a viscoelastic body spinning around its shortest body axis, with spin aligned with orbital spin axis, and in circular orbit about a point mass. The torque or drift rate can be estimated from that predicted for a sphere with equivalent volume if multiplied by 0.5 (1 + b^4/a^4)(b/a)^{-4/3} (c/a)^{-α _c} where b/a and c/a are the body axis ratios and index αc ≈ 1.05 is consistent with the random lattice mass spring model simulations but αc = 4/3 suggested by scaling estimates. A homogeneous body with axis ratios 0.5 and and 0.8, like Haumea, has orbital semi-major axis drift rate about twice as fast as a spherical body with the same mass, volume and material properties. A simulation approximating a mostly rocky body but with 20% of its mass as ice concentrated at its ends has a drift rate 10 times faster than the equivalent homogeneous rocky sphere. However, this increase in drift rate is not enough to allow Haumea's satellite, Hi'iaka, to have tidally drifted away from Haumea to its current orbital semi-major axis.

  2. Reduced spin-down rate of PSR J0738-4042 explained as due to an asteroid disruption event

    NASA Astrophysics Data System (ADS)

    Yu, Yong-Bo; Huang, Yong-Feng

    2016-05-01

    Long term observations by Brook et al. reveal that the derivative of rotational frequency of PSR J0738-4042 changed abruptly in 2005. Originally, the spin-down rate was relatively stable, with the rotational frequency derivative being ‑1.14×10‑14 s‑2. After September 2005, the derivative began to rise. About 1000 days later, it arrived at another relatively stable value of about ‑0.98 × 10‑14 s‑2, indicating that the pulsar is spinning-down relatively slowly. To explain the observed change in spin-down rate, we resort to an asteroid disrupted by PSR J0738-4042. In our model, the orbital angular momentum of the asteroid is assumed to be parallel to that of the rotating pulsar, so that the pronounced reduction in the spin-down rate can be naturally explained as due to the transfer of angular momentum from the disrupted material to the central pulsar. The derived magnetospheric radius is about 7.0 × 109 cm, which is smaller than the tidal disruption radius (8.7 × 1010 cm). Our model is self-consistent. It is shown that the variability in the spin-down rate of PSR J0738-4042 can be quantitatively accounted for by accretion from the asteroid disrupted by the central pulsar.

  3. The variable spin-down rate of the transient magnetar XTE J1810-197

    NASA Astrophysics Data System (ADS)

    Pintore, Fabio; Bernardini, Federico; Mereghetti, Sandro; Esposito, Paolo; Turolla, Roberto; Rea, Nanda; Coti Zelati, Francesco; Israel, Gian Luca; Tiengo, Andrea; Zane, Silvia

    2016-05-01

    We have analysed XMM-Newton and Chandra observations of the transient magnetar XTE J1810-197 spanning more than 11 yr, from the initial phases of the 2003 outburst to the current quiescent level. We investigated the evolution of the pulsar spin period and we found evidence for two distinct regimes: during the outburst decay, dot{ν } was highly variable in the range -(2-4.5) × 10-13 Hz s-1, while during quiescence the spin-down rate was more stable at an average value of -1 × 10-13 Hz s-1. Only during ˜3000 d (from MJD 54165 to MJD 56908) in the quiescent stage it was possible to find a phase-connected timing solution, with dot{ν }=-4.9× 10^{-14} Hz s-1, and a positive second frequency derivative, ddot{ν }=1.8× 10^{-22} Hz s-2. These results are in agreement with the behaviour expected if the outburst of XTE J1810-197 was due to a strong magnetospheric twist.

  4. Exploration of spin-down rate of neutron stars in high-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Dai, Hai-Lang; Liu, Xi-Wei; Li, Xiang-Dong

    2016-04-01

    We use the evolutionary population synthesis method to investigate the statistical properties of the wind-fed neutron-star (NS) compact (Porb < 10 d) high-mass X-ray binaries (HMXBs) in our Galaxy, based on different spin-down models. Model 1 assumes that the surrounding material is treated as forming a quasi-static atmosphere. Model 2 assumes that the characteristic velocity of matter and the typical Alfvén velocity of material in the magnetospheric boundary layer are comparable to the sound speed in the external medium. We find that the spin-down rate in the supersonic propeller phase in either model 1 or model 2 is too low to produce the observed number of compact HMXBs. Model 3 assumes that the infalling material is ejected with the corotation velocity at the magnetospheric radius when the magnetospheric radius is larger than the corotation radius. Model 4 uses simple integration of the magnetic torque over the magnetosphere. Both models 3 and 4 have a larger spin down rate than that given by model 1 or 2. We also find that models 3 and 4 can predict a reasonable number of observed wind-fed NS compact HMXBs. By comparing our calculated results with the observed particular distributions of wind-fed NS compact HMXBs in a Ps versus Porb diagram, we find that the subsonic propeller phase may not exist at all. However, the spin-down rates in models 3 and 4 both seem reasonable to produce the observed distribution of wind-fed NS compact HMXBs in the Ps versus Porb diagram. We cannot find which spin-down rate seems more reasonable from our calculations.

  5. X-Ray Spectra of Young Pulsars and Their Wind Nebulae: Dependence on Spin-Down Energy Loss Rate

    NASA Technical Reports Server (NTRS)

    Gotthelf, E. V.

    2003-01-01

    An observational model is presented for the spectra of young rotation-powered pulsars and their nebulae based on a study of nine bright Crab-like pulsar systems observed with the Chandra X-ray observatory. A significant correlation is discovered between the X-ray spectra of these pulsars and that of their associated pulsar wind nebulae, both of which are observed to be a function of the spin-down energy loss rate, E. The 2-10 keV spectra of these objects are well characterized by an absorbed power-law model with photon indices, Gamma, in the range of 0.6 < Gamma (sub PSR) < 2.1 and 1.3 < Gamma(sub PWN) < 2.3, for the pulsars and their nebulae, respectively. A linear regression fit relating these two sets of indexes yields Gamma(sub PWN) = 0.91 +/- 0.18 + (0.66 +/- 0.11) Gamma (sub PSR), with a correlation coefficient of r = 0.97. The spectra of these pulsars are found to steepen as Gamma = Gamma(sub max) + alpha E (exp -1/2), with Gamma(sub max) providing an observational limit on the spectral slopes of young rotation-powered pulsars. These results reveal basic properties of young pulsar systems, allow new observational constraints on models of pulsar wind emission, and provide a means of predicting the energetics of pulsars lacking detected pulsations.

  6. A grid of MHD models for stellar mass loss and spin-down rates of solar analogs

    SciTech Connect

    Cohen, O.; Drake, J. J.

    2014-03-01

    Stellar winds are believed to be the dominant factor in the spin-down of stars over time. However, stellar winds of solar analogs are poorly constrained due to observational challenges. In this paper, we present a grid of magnetohydrodynamic models to study and quantify the values of stellar mass loss and angular momentum loss rates as a function of the stellar rotation period, magnetic dipole component, and coronal base density. We derive simple scaling laws for the loss rates as a function of these parameters, and constrain the possible mass loss rate of stars with thermally driven winds. Despite the success of our scaling law in matching the results of the model, we find a deviation between the 'solar dipole' case and a real case based on solar observations that overestimates the actual solar mass loss rate by a factor of three. This implies that the model for stellar fields might require a further investigation with additional complexity. Mass loss rates in general are largely controlled by the magnetic field strength, with the wind density varying in proportion to the confining magnetic pressure B {sup 2}. We also find that the mass loss rates obtained using our grid models drop much faster with the increase in rotation period than scaling laws derived using observed stellar activity. For main-sequence solar-like stars, our scaling law for angular momentum loss versus poloidal magnetic field strength retrieves the well-known Skumanich decline of angular velocity with time, Ω{sub *}∝t {sup –1/2}, if the large-scale poloidal magnetic field scales with rotation rate as B{sub p}∝Ω{sub ⋆}{sup 2}.

  7. Spin down of rotating compact magnetized strange stars in general relativity

    NASA Astrophysics Data System (ADS)

    Abdujabbarov, Ahmadjon

    2016-07-01

    We find that in general relativity slow down of the pulsar rotation due to the magnetodipolar radiation is more faster for the strange star with comparison to that for the ordinary neutron star of the same mass. Comparison with astrophysical observations on pulsars spindown data may provide an evidence for the strange star existence and, thus, serve as a test for distinguishing it from the neutron star.

  8. On the Spin-down of Intermittent Pulsars

    NASA Astrophysics Data System (ADS)

    Li, Jason; Spitkovsky, Anatoly; Tchekhovskoy, Alexander

    2012-02-01

    Magnetospheres of pulsars are thought to be filled with plasma, and variations in plasma supply can affect both pulsar emission properties and spin-down rates. A number of recently discovered "intermittent" pulsars switch between two distinct states: an "on," radio-loud state, and an "off," radio-quiet state. Spin-down rates in the two states differ by a large factor, ~1.5-2.5, which is not easily understood in the context of current models. In this Letter, we present self-consistent numerical solutions of "on" and "off" states of intermittent pulsar magnetospheres. We model the "on" state as a nearly ideal force-free magnetosphere with abundant magnetospheric plasma supply. The lack of radio emission in the "off" state is associated with plasma supply disruption that results in lower plasma density on the open field lines. We model the "off" state using nearly vacuum conditions on the open field lines and nearly ideal force-free conditions on the closed field lines, where plasma can remain trapped even in the absence of pair production. The toroidal advection of plasma in the closed zone in the "off" state causes spin-downs that are a factor of ~2 higher than vacuum values, and we naturally obtain a range of spin-down ratios between the "on" and "off" states, ~1.2-2.9, which corresponds to a likely range of pulsar inclination angles of 30°-90°. We consider the implications of our model to a number of poorly understood but possibly related pulsar phenomena, including nulling, timing noise, and rotating radio transients.

  9. A QUARTER-CENTURY OF OBSERVATIONS OF COMET 10P/TEMPEL 2 AT LOWELL OBSERVATORY: CONTINUED SPIN-DOWN, COMA MORPHOLOGY, PRODUCTION RATES, AND NUMERICAL MODELING

    SciTech Connect

    Knight, Matthew M.; Schleicher, David G.; Schwieterman, Edward W.; Christensen, Samantha R.; Farnham, Tony L.

    2012-11-01

    We report on photometry and imaging of Comet 10P/Tempel 2 obtained at Lowell Observatory from 1983 through 2011. We measured a nucleus rotation period of 8.950 {+-} 0.002 hr from 16 nights of imaging acquired between 2010 September and 2011 January. This rotation period is longer than the period we previously measured in 1999, which was itself longer than the period measured in 1988, and demonstrates that Tempel 2 is continuing to spin down, presumably due to torques caused by asymmetric outgassing. A nearly linear jet was observed which varied little during a rotation cycle in both R and CN images acquired during the 1999 and 2010 apparitions. We measured the projected direction of this jet throughout the two apparitions and, under the assumption that the source region of the jet was near the comet's pole, determined a rotational pole direction of R.A./decl. = 151 Degree-Sign /+59 Degree-Sign from CN measurements and R.A./decl. = 173 Degree-Sign /+57 Degree-Sign from dust measurements (we estimate a circular uncertainty of 3 Degree-Sign for CN and 4 Degree-Sign for dust). Different combinations of effects likely bias both gas and dust solutions and we elected to average these solutions for a final pole direction of R.A./decl. = 162 Degree-Sign {+-} 11 Degree-Sign /+58 Degree-Sign {+-} 1 Degree-Sign . Photoelectric photometry was acquired on 3 nights in 1983, 2 nights in 1988, 19 nights in 1999/2000, and 10 nights in 2010/2011. The activity exhibited a steep 'turn-on' {approx}3 months prior to perihelion (the exact timing of which varies) and a relatively smooth decline after perihelion. The activity during the 1999 and 2010 apparitions was similar; limited data in 1983 and 1988 (along with IUE data from the literature) were systematically higher and the difference cannot be explained entirely by the smaller perihelion distance. We measured a 'typical' composition, in agreement with previous investigators. Monte Carlo numerical modeling with our pole solution best

  10. A Quarter-century of Observations of Comet 10P/Tempel 2 at Lowell Observatory: Continued Spin-down, Coma Morphology, Production Rates, and Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Knight, Matthew M.; Schleicher, David G.; Farnham, Tony L.; Schwieterman, Edward W.; Christensen, Samantha R.

    2012-11-01

    We report on photometry and imaging of Comet 10P/Tempel 2 obtained at Lowell Observatory from 1983 through 2011. We measured a nucleus rotation period of 8.950 ± 0.002 hr from 16 nights of imaging acquired between 2010 September and 2011 January. This rotation period is longer than the period we previously measured in 1999, which was itself longer than the period measured in 1988, and demonstrates that Tempel 2 is continuing to spin down, presumably due to torques caused by asymmetric outgassing. A nearly linear jet was observed which varied little during a rotation cycle in both R and CN images acquired during the 1999 and 2010 apparitions. We measured the projected direction of this jet throughout the two apparitions and, under the assumption that the source region of the jet was near the comet's pole, determined a rotational pole direction of R.A./decl. = 151°/+59° from CN measurements and R.A./decl. = 173°/+57° from dust measurements (we estimate a circular uncertainty of 3° for CN and 4° for dust). Different combinations of effects likely bias both gas and dust solutions and we elected to average these solutions for a final pole direction of R.A./decl. = 162° ± 11°/+58° ± 1°. Photoelectric photometry was acquired on 3 nights in 1983, 2 nights in 1988, 19 nights in 1999/2000, and 10 nights in 2010/2011. The activity exhibited a steep "turn-on" ~3 months prior to perihelion (the exact timing of which varies) and a relatively smooth decline after perihelion. The activity during the 1999 and 2010 apparitions was similar; limited data in 1983 and 1988 (along with IUE data from the literature) were systematically higher and the difference cannot be explained entirely by the smaller perihelion distance. We measured a "typical" composition, in agreement with previous investigators. Monte Carlo numerical modeling with our pole solution best replicated the observed coma morphology for a source region located near a comet latitude of +80° and having a

  11. Dual Spin-down States of the Pulsar J1001-5507

    NASA Astrophysics Data System (ADS)

    Chukwude, A. E.; Buchner, S.

    2012-01-01

    Quasi-regular timing observations obtained, using the 26 m Hartebeesthoek Radio Astronomy Observatory radiotelescope near center frequencies of 1.668 and 2.272 GHz, between 1985 July and 2005 August have given a further insight into the long-term spin-down behavior of the pulsar J1001-5507 (B0959-54). Here, we show that the spin-down of the pulsar during ~20 years is dominated by dual spin-down modes characterized by two discrete and nearly stable spin-down rates (\\dot{\

  12. Switched magnetospheric regulation of pulsar spin-down.

    PubMed

    Lyne, Andrew; Hobbs, George; Kramer, Michael; Stairs, Ingrid; Stappers, Ben

    2010-07-23

    Pulsars are famed for their rotational clocklike stability and their highly repeatable pulse shapes. However, it has long been known that there are unexplained deviations (often termed timing noise) from the rate at which we predict these clocks should run. We show that timing behavior often results from two different spin-down rates. Pulsars switch abruptly between these states, often quasi-periodically, leading to the observed spin-down patterns. We show that for six pulsars the timing noise is correlated with changes in the pulse shape. Many pulsar phenomena, including mode changing, nulling, intermittency, pulse-shape variability, and timing noise, are therefore linked and are caused by changes in the pulsar's magnetosphere. We consider the possibility that high-precision monitoring of pulse profiles could lead to the formation of highly stable pulsar clocks. PMID:20576852

  13. Spin-down Dynamics of Magnetized Solar-type Stars

    NASA Astrophysics Data System (ADS)

    Oglethorpe, R. L. F.; Garaud, P.

    2013-12-01

    It has long been known that solar-type stars undergo significant spin-down, via magnetic braking, during their main-sequence lifetimes. However, magnetic braking only operates on the surface layers; it is not yet completely understood how angular momentum is transported within the star and how rapidly the spin-down information is communicated to the deep interior. In this work, we use insight from recent progress in understanding internal solar dynamics to model the interior of other solar-type stars. We assume, following Gough & McIntyre, that the bulk of the radiation zone of these stars is held in uniform rotation by the presence of an embedded large-scale primordial field, confined below a stably stratified, magnetic-free tachocline by large-scale meridional flows downwelling from the convection zone. We derive simple equations to describe the response of this model interior to spin-down of the surface layers, which are identical to the two-zone model of MacGregor & Brenner, with a coupling timescale proportional to the local Eddington-Sweet timescale across the tachocline. This timescale depends both on the rotation rate of the star and on the thickness of the tachocline, and it can vary from a few hundred thousand years to a few Gyr, depending on stellar properties. Qualitative predictions of the model appear to be consistent with observations, although they depend sensitively on the assumed functional dependence of the tachocline thickness on the stellar rotation rate.

  14. SPIN-UP/SPIN-DOWN MODELS FOR TYPE Ia SUPERNOVAE

    SciTech Connect

    Stefano, R. Di; Voss, R.

    2011-09-01

    In the single-degenerate scenario for Type Ia supernovae (SNe Ia), a white dwarf (WD) must gain a significant amount of matter from a companion star. Because the accreted mass carries angular momentum, the WD is likely to achieve fast spin periods, which can increase the critical mass, M{sub crit}, needed for explosion. When M{sub crit} is higher than the maximum mass achieved by the WD, the central regions of the WD must spin down before it can explode. This introduces super-Chandrasekhar single-degenerate explosions, and a delay between the completion of mass gain and the time of the explosion. Matter ejected from the binary during mass transfer therefore has a chance to become diffuse, and the explosion occurs in a medium with a density similar to that of typical regions of the interstellar medium. Also, either by the end of the WD's mass increase or else by the time of explosion, the donor may exhaust its stellar envelope and become a WD. This alters, generally diminishing, explosion signatures related to the donor star. Nevertheless, the spin-up/spin-down model is highly predictive. Prior to explosion, progenitors can be super-M{sub Ch} WDs in either wide binaries with WD companions or cataclysmic variables. These systems can be discovered and studied through wide-field surveys. Post-explosion, the spin-up/spin-down model predicts a population of fast-moving WDs, low-mass stars, and even brown dwarfs. In addition, the spin-up/spin-down model provides a paradigm which may be able to explain both the similarities and the diversity observed among SNe Ia.

  15. Discovery of Pulsed Gamma Rays and a New Spin-Down State of the LMC Pulsar B0540-69

    NASA Astrophysics Data System (ADS)

    Marshall, Francis E.; Guillemot, Lucas; Kust Harding, Alice; Martin, Pierrick; Smith, David A.

    2016-01-01

    The young pulsar B0540-69 in the nearby Large Magellanic Cloud has the third largest spin-down luminosity of the ~2500 known pulsars. Multi-year observations with Fermi/LAT using the ephemerides from RXTE reveal that B0540-69 is the most luminous gamma-ray pulsar ever detected. Its pulsed luminosity above 100 MeV is 5.7x1036 erg/s, about 20 times brighter than the Crab Pulsar, the next brightest. The pulse profile in gamma rays is similar to that seen in X-rays and optical light; the giant radio pulses align with the shoulders of the high-energy profiles. The detection of B0540-69 in gamma rays offers a new look at particle acceleration and emission in the magnetospheres of very young pulsars. Unpulsed gamma-ray emission has also been detected from PSR J0537-6910, another young pulsar in the LMC. The two pulsars contribute most of the gamma-ray emission from the 30 Doradus nebula, indicating that cosmic rays contribute only a small part. Recent monitoring of B0540-69 with the Swift/XRT shows a large, sudden, and persistent increase in the spin-down rate of B0540-69. The relative increase in the spin-down rate of 36% is unprecedented for B0540-69. No accompanying change in the spin rate was seen, and no change was seen in the pulsed X-ray emission from B0540-69 following the change in the spin-down rate. Such large relative changes in the spin-down rate are seen in the recently discovered class of ``intermittent pulsars'', and we compare the properties of B0540-69 to such pulsars. We consider possible changes in the magnetosphere of the pulsar that could cause such a large change in the spin-down rate. These changes are likely to result in a new braking index for the pulsar. We report on continued monitoring with Swift/XRT to determine the new braking index and to detect a new state change, should it occur.

  16. DUAL SPIN-DOWN STATES OF THE PULSAR J1001-5507

    SciTech Connect

    Chukwude, A. E.; Buchner, S.

    2012-01-20

    Quasi-regular timing observations obtained, using the 26 m Hartebeesthoek Radio Astronomy Observatory radiotelescope near center frequencies of 1.668 and 2.272 GHz, between 1985 July and 2005 August have given a further insight into the long-term spin-down behavior of the pulsar J1001-5507 (B0959-54). Here, we show that the spin-down of the pulsar during {approx}20 years is dominated by dual spin-down modes characterized by two discrete and nearly stable spin-down rates ({nu}-dot{sub low}=-0.24871x10{sup -13} s{sup -2} and {nu}-dot{sub high}=-0.25195x10{sup -13} s{sup -2}). Our analysis demonstrates that the switching of the pulsar's spin-down rate from {nu}-dot{sub low} to {nu}-dot{sub high} modes occurred over about 800 days (between about MJD 48500 and MJD 49300) at a steady rate of {approx}-4.6 Multiplication-Sign 10{sup -24} s{sup -3}, after which the pulsar was found to be slowing down 1.3% faster. It is observed that the extreme pulse profile shapes at the two spin-down modes are notably different, while the interval of steady switching between the spin-down modes is coincident with evidence for some correlated pulse shape variations. We discuss these results in light of the current understanding of various mechanisms for radio pulsar spin-down modulation.

  17. Spin-down of neutron stars by neutrino emission

    SciTech Connect

    Dvornikov, Maxim; Dib, Claudio

    2010-08-15

    We study the spin-down of a neutron star during its early stages due to the neutrino emission. The mechanism we consider is the subsequent collisions of the produced neutrinos with the outer shells of the star. We find that this mechanism can indeed slow down the star rotation but only in the first tens of seconds of the core formation, which is when the appropriate conditions of flux and collision rate are met. We find that this mechanism can extract less than 1% of the star angular momentum, a result which is much less than previously estimated by other authors.

  18. Solar spin-down with internal magnetic fields

    NASA Astrophysics Data System (ADS)

    Charbonneau, P.; MacGregor, K. B.

    1992-09-01

    We investigate the rotational evolution of a solar-type star containing a large-scale poloidal magnetic field in its radiative core, in response to the torque applied to it by magnetically coupled wind. Our model takes into account both the generation of a toroidal magnetic component via shearing of the existing poloidal component by differential rotation, as well as the back-reaction on the differential rotation due to Lorentz forces associated with the toroidal field. Our computations demonstrate the existence of classes of large-scale poloidal magnetic fields allowing rapid spin-down of the surface layers shortly after the arrival on the zero-age main sequence, while producing weak internal differential rotation in the radiative core by the solar age. This indicates that the constraints brought about by rotational evolution of solar analogs in young clusters and by helioseismology are not incompatible with the existence of large-scale magnetic fields in stellar radiative interiors. The present surface solar rotation rate is also shown to be a poor indicator of the strength and geometry of hypothetical poloidal magnetic fields pervading the solar radiative interior.

  19. Gravitational wave emission and spin-down of young pulsars

    SciTech Connect

    Alford, Mark G.; Schwenzer, Kai

    2014-01-20

    The rotation frequencies of young pulsars are systematically below their theoretical Kepler limit. r-modes have been suggested as a possible explanation for this observation. With the help of semi-analytic expressions that make it possible to assess the uncertainties of the r-mode scenario due to the impact of uncertainties in underlying microphysics, we perform a quantitative analysis of the spin-down and the emitted gravitational waves of young pulsars. We find that the frequency to which r-modes spin-down a young neutron star (NS) is surprisingly insensitive to both the microscopic details and the saturation amplitude. Comparing our result to astrophysical data, we show that for a range of sufficiently large saturation amplitudes r-modes provide a viable spin-down scenario and that all observed young pulsars are very likely already outside the r-mode instability region. Therefore, the most promising sources for gravitational wave detection are unobserved NSs associated with recent supernovae, and we find that advanced LIGO should be able to see several of them. Our analysis shows that despite the coupling of the spin-down and thermal evolution, a power-law spin-down with an effective braking index n {sub rm} ≤ 7 is realized. Because of this, the gravitational wave strain amplitude is completely independent of both the r-mode saturation amplitude and the microphysics and depends on the saturation mechanism only within some tens of percent. However, the gravitational wave frequency depends on the amplitude, and we provide the required expected timing parameter ranges to look for promising sources in future searches.

  20. On the Dramatic Spin-up/Spin-Down Torque Reversals in Accreting Pulsars

    NASA Technical Reports Server (NTRS)

    Nelson, Robert W.; Bildsten, Lars; Chakrabarty, Deepto; Finger, Mark H.; Koh, Danny T.; Prince, Thomas A.; Rubin, Bradley C.; Scott, D. Mathew; Vaughan, Brian A.; Wilson, Robert B.

    1997-01-01

    Dramatic torque reversals between spin-up and spin-down have been observed in half of the persistent X-ray pulsars monitored by the Burst and Transient Space Experiment (BATSE) all-sky monitor on the Compton Gamma Ray Observatory. Theoretical models developed to explain early pulsar timing data can explain spin-down torques via a disk-magnetosphere interaction if the star nearly corotates with the inner accretion disk. To produce the observed BATSE torque reversals, however, these equilibrium models require the disk to alternate between two mass accretion rates, with M+/- producing accretion torques of similar magnitude but always of opposite sign. Moreover, in at least one pulsar (GX 1+4) undergoing secular spin-down, the neutron star spins down faster during brief (approximately 20 day) hard X-ray flares-this is opposite the correlation expected from standard theory, assuming that BATSE pulsed flux increases with mass accretion rate. The 10 day to 10 yr intervals between torque reversals in these systems are much longer than any characteristic magnetic or viscous timescale near the inner disk boundary and are more suggestive of a global disk phenomenon. We discuss possible explanations of the observed torque behavior. Despite the preferred sense of rotation defined by the binary orbit, the BATSE observations are surprisingly consistent with an earlier suggestion for GX 1+4: the disks in these systems somehow alternate between episodes of prograde and retrograde rotation. We are unaware of any mechanism that could produce a stable retrograde disk in a binary undergoing Roche lobe overflow, but such flip-flop behavior does occur in numerical simulations of wind-fed systems. One possibility is that the disks in some of these binaries are fed by an X-ray-excited wind.

  1. Spin-up and spin-down in a half cone: A pathological situation or not?

    NASA Astrophysics Data System (ADS)

    Li, L.; Patterson, M. D.; Zhang, K.; Kerswell, R. R.

    2012-11-01

    The spin-up and spin-down of a fluid in a rapidly rotating, fluid-filled, and closed half cone are studied both numerically and experimentally. This unusual set up is of interest because it represents a pathological case for the classical linear theory of Greenspan and Howard [J. Fluid Mech. 17, 385-404 (1963), 10.1017/S0022112063001415] since there are no closed geostrophic contours nor a denumerable set of inertial waves (even a modified theory incorporating Rossby waves by Pedlosky and Greenspan [J. Fluid Mech. 27, 291-304 (1967), 10.1017/S0022112067000321]—relies on geostrophy to leading order). The linearised spin-up/spin-down dynamics in a half cone is found to be dominated by topographical effects which force an ageostrophic leading balance and cause the large-scale starting vorticity to coherently move into the "westward" corner of the half cone for both spin-up and spin-down. Once there, viscous boundary layer effects take over as the dominant process ensuring that the spin-up/spin-down time scales conventionally with E-1/2, where E is the Ekman number. The numerical coefficient in this time scale is approximately a quarter of that for a full cone when the semi-angle is 30°. Nonlinear spin up from rest is also studied as well as an impulsive 50% reduction in the rotation rate which shows boundary layer separation and small scales. We conclude that spin-up in a rapidly rotating half cone is not pathological because the fluid dynamics is fundamentally the same as that in a container with small topography: in both topography-forced vortex stretching is to the fore.

  2. Non-monotonous character of single radio pulsar spin-down

    NASA Astrophysics Data System (ADS)

    Biryukov, A. V.; Beskin, G. M.; Karpov, S. V.

    2011-10-01

    Our paper is dedicated to the problem of anomalous values of braking indices n obs and spin frequency second derivatives ddot ν of isolated radio pulsars. Observations of these objects for over 40 years have shown that in addition to the complex short-term irregular component in the evolution of the pulsars' frequency, secular values of its second derivative are orders of magnitude greater than the predicted theoretical ones, and in a good half of cases—they are even negative. We earlier attributed this behavior of secular values of the second derivative to the presence of a cyclic component in the secular evolution of ν( t), with a characteristic recurrence time of thousands to tens of thousand years. We continue to develop this hypothesis based on a more detailed statistical analysis of the characteristics of 297 isolated radio pulsars: we analyze the model of these objects spin-down, consisting of two components, monotonic and cyclic, and determine their parameters. We demonstrate that the monotonic spin-down component is described by the classical magnetodipolar power law with an braking index of about 3, while the large amplitude of the cyclic component causes a significant variation of the observed spin-down rate (dot ν ) (with respect to magnetodipolar one), and fully determines the anomalous values of ddot ν and n obs. An important consequence of the existence of a cyclic component of the pulsar rotational variations is the difference between their characteristic ages and respective secular values (by about 0.5-5 times). This allows to explainthe observed discrepancy of the characteristic and physical ages of some objects, as well as very large, up to 108 years, characteristic ages of some old pulsars. The paper argues that the cyclic component of the observed spin-down is due to the long-term precession of neutron stars around their magnetic axes, which, in particular, may be driven by the anomalous braking torque. In the model of purely

  3. Timing Young Pulsars: Challenges to Standard Pulsar Spin-Down Models

    NASA Astrophysics Data System (ADS)

    Livingstone, Margaret Anne

    Pulsars are rapidly rotating neutron stars which are often noted for their very regular rotation rates. Young pulsars, however, frequently exhibit two types of deviations from steady spin down, "glitches" - sudden jumps in spin frequency, which provide insight into pulsar interiors, and "timing noise," a smooth stochastic wander of the pulse phase over long time periods. The youngest pulsars also offer a window into the physics that govern pulsar spin down via the measurement of the "braking index" - a parameter that relates the observable spin frequency of the pulsar with the slowing down torque acting on the neutron star. This thesis discusses long-term timing observations of two young pulsars. First, we present observations of PSR J0205+6449, acquired with the Green Bank Telescope, the Jodrell Bank Observatory and the Rossi X-ray Timing Explorer . We present phase-coherent timing analyses showing timing noise and two spin-up glitches. We also present an X-ray pulse profile analysis showing that the pulsar is detected up to ∼40 keV and does not vary appreciably over four years. We report the phase offset between the radio and X-ray pulse, showing that the radio pulse leads by φ = 0.10 ± 0.01 in phase. We compile measurements of phase offsets for this and other X-ray and γ-ray pulsars and show that there is no relationship between pulse period and phase offset. Next, we present 10 years of monitoring of PSR J1846-0258 with the Rossi X-ray Timing Explorer . We report the first measurement of the braking index for this pulsar, n = 2.65 ± 0.01, only the sixth such measurement ever made, and show that the pulsar experienced a small glitch in 2001. In May 2006, PSR J1846-0258 was briefly transformed: it exhibited a series of X-ray bursts, a dramatic increase in the source flux, and significant softening of its X-ray spectrum - behaviours best explained in the context of the magnetar model. PSR J1846-0258 was thus identified as the first rotation-powered pulsar

  4. A Magnetar Wind Nebula: the Spin-down-Powered Wind is not Enough

    NASA Astrophysics Data System (ADS)

    Gill, Ramandeep; Granot, Jonathan; Baring, Matthew G.; Gelfand, Joseph; Younes, George A.; Kargaltsev, Oleg; Kust Harding, Alice; Kouveliotou, Chryssa; Huppenkothen, Daniela

    2016-04-01

    Magnetars are a small class of slowly-rotating (P~2-12 s) highly magnetized (surface dipole fields ~10^{14}-10^{15} G) that show a variety of bursting activity, powered by the decay of their super-strong magnetic field. While many rotation-powered pulsars are surrounded by a pulsar wind nebula (PWN) powered by their spin-down MHD wind (the prime example being the Crab nebula), only now has the first magnetar wind nebula (MWN) been discovered in X-rays, around Swift J1834.9-0846. We have analyzed this system in detail to see what can be learned from it. We find good evidence that unlike normal PWNe, this MWN cannot be powered by its spin-down MHD wind alone. A considerable contribution to the MWN energy should come from a different source, most likely sporadic outflows associated with the magnetar's bursting activity. This suggests that the MWN may serve as a calorimeter, and provide a new and robust estimate for the magnetar's long-term mean energy output rate in outflows. We also discuss other interesting aspects of this system.

  5. Beating the Spin-down Limit on Gravitational Wave Emission from the Vela Pulsar

    NASA Astrophysics Data System (ADS)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Antonucci, F.; Arai, K.; Arain, M. A.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barker, D.; Barnum, S.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Basti, A.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Bejger, M.; Beker, M. G.; Bell, A. S.; Belletoile, A.; Belopolski, I.; Benacquista, M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birindelli, S.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, S.; Bosi, L.; Bouhou, B.; Boyle, M.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brummit, A.; Budzyński, R.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet-Castell, J.; Burmeister, O.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cain, J.; Calloni, E.; Camp, J. B.; Campagna, E.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chaibi, O.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Chung, S.; Clara, F.; Clark, D.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, R.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M.; Coulon, J.-P.; Coward, D. M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Culter, R. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Das, K.; Dattilo, V.; Daudert, B.; Daveloza, H.; Davier, M.; Davies, G.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; del Prete, M.; Dent, T.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Emilio, M. Di Paolo; Di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Dorsher, S.; Douglas, E. S. D.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Engel, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Flaminio, R.; Flanigan, M.; Foley, S.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Galimberti, M.; Gammaitoni, L.; Garcia, J.; Garofoli, J. A.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gupta, R.; Gustafson, E. K.; Gustafson, R.; Hage, B.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Hayler, T.; Heefner, J.; Heitmann, H.; Hello, P.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Herrera, V.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hong, T.; Hooper, S.; Hosken, D. J.; Hough, J.; Howell, E. J.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kanner, J. B.; Katsavounidis, E.; Katzman, W.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Kelner, M.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, H.; Kim, N.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, R.; Kwee, P.; Landry, M.; Lantz, B.; Lastzka, N.; Lazzarini, A.; Leaci, P.; Leong, J.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lu, P.; Luan, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marandi, A.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McKechan, D. J. A.; Meadors, G.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Mercer, R. A.; Merill, L.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mino, Y.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Moe, B.; Moesta, P.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morgia, A.; Mosca, S.; Moscatelli, V.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murray, P. G.; Nash, T.; Nawrodt, R.; Nelson, J.; Neri, I.; Newton, G.; Nishida, E.; Nishizawa, A.; Nocera, F.; Nolting, D.; Ochsner, E.; O'Dell, J.; Ogin, G. H.; Oldenburg, R. G.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Parameswaran, A.; Pardi, S.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pathak, D.; Pedraza, M.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Persichetti, G.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Podkaminer, J.; Poggiani, R.; Pöld, J.; Postiglione, F.; Prato, M.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Ramet, C. R.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Redwine, K.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Roberts, P.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Rolland, L.; Rollins, J.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sakata, S.; Sakosky, M.; Salemi, F.; Salit, M.; Sammut, L.; Sancho de la Jordana, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Saraf, S.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Satterthwaite, M.; Saulson, P. R.; Savage, R.; Schilling, R.; Schlamminger, S.; Schnabel, R.; Schofield, R. M. S.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Searle, A. C.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shihan Weerathunga, T.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Singer, L.; Sintes, A. M.; Skelton, G.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Smith, R.; Somiya, K.; Sorazu, B.; Soto, J.; Speirits, F. C.; Sperandio, L.; Stefszky, M.; Stein, A. J.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Szokoly, G. P.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Titsler, C.; Tokmakov, K. V.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Trias, M.; Tseng, K.; Turner, L.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vaishnav, B.; Vajente, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vasuth, M.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vocca, H.; Vorvick, C.; Vyachanin, S. P.; Waldman, S. J.; Wallace, L.; Wanner, A.; Ward, R. L.; Was, M.; Wei, P.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wen, S.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, H. R.; Williams, L.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Woan, G.; Wooley, R.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zanolin, M.; Zhang, L.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration; Buchner, S.; Hotan, A.; Palfreyman, J.

    2011-08-01

    We present direct upper limits on continuous gravitational wave emission from the Vela pulsar using data from the Virgo detector's second science run. These upper limits have been obtained using three independent methods that assume the gravitational wave emission follows the radio timing. Two of the methods produce frequentist upper limits for an assumed known orientation of the star's spin axis and value of the wave polarization angle of, respectively, 1.9 × 10-24 and 2.2 × 10-24, with 95% confidence. The third method, under the same hypothesis, produces a Bayesian upper limit of 2.1 × 10-24, with 95% degree of belief. These limits are below the indirect spin-down limit of 3.3 × 10-24 for the Vela pulsar, defined by the energy loss rate inferred from observed decrease in Vela's spin frequency, and correspond to a limit on the star ellipticity of ~10-3. Slightly less stringent results, but still well below the spin-down limit, are obtained assuming the star's spin axis inclination and the wave polarization angles are unknown.

  6. The influence of spin-down on thermal evolution of hybrid stars

    NASA Astrophysics Data System (ADS)

    Kang, Miao; Wang, Xiao-Dong

    2014-11-01

    As neutron stars spin-down, quark matter may appear in the core forming so-called hybrid stars. We investigate the evolution behavior of rotating hybrid stars which have tortuous thermal evolution curves because of a change of chemical composition and the appearance of different powerful neutrino reactions in the process of spin-down. The emergence of the nucleon direct Urca processes can lead to an abrupt rise of the rate of neutrino emission. Quark deconfinement heating can both delay the cooling dramatically and raise the temperature of the stars over a period of time. Comparing the thermal evolution curves with observations, our investigation shows that the thermal evolution curves of rotating hybrid stars are consistent with the most of pulsar’s data despite the onset of fast cooling. Massive rotating hybrid stars model could be a good choice for some “cooler” stars. The Cas A supernova remnant contains a young neutron star (≈330 yr old) which is one of the most important isolated neutron stars in testing the thermal evolution theory of neutron star. We find the onset of the nucleon direct Urca process of the rotating hybrid star with heating model also could be an alternative explanation for the rapid cooling of Cas A neutron star.

  7. SPIN-DOWN MEASUREMENT OF PSR J1813-1749: THE ENERGETIC PULSAR POWERING HESS J1813-178

    SciTech Connect

    Halpern, J. P.; Gotthelf, E. V.; Camilo, F.

    2012-07-01

    Two new X-ray timing observations of the 44.7 ms pulsar in G12.82-0.02/HESS J1813-178 were obtained with Chandra and XMM-Newton to determine its precise spin-down rate. With a period derivative of P-dot 1.265 Multiplication-Sign 10{sup -13}, PSR J1813-1749 is the third most energetic pulsar in the Galaxy, having spin-down luminosity E-dot 5.6 Multiplication-Sign 10{sup 37} erg s{sup -1}. Lack of pulsed detection in a deep radio search from the Green Bank Telescope, and in {gamma}-rays from Fermi, are reported. We reconsider the distance to PSR J1813-1749/G12.82-0.02 in view of its large X-ray measured column density, N{sub H} = 10 Multiplication-Sign 10{sup 22} cm{sup -2}, which exceeds the visual extinction A{sub V} = 9.1 to a young stellar cluster at d = 4.8 kpc that has been associated with it. Although the distance may well be larger, existing data do not constrain it further. The small radiative output of PSR J1813-1749/G12.82-0.02 in all bands would not exceed its spin-down power at any distance in the Galactic disk.

  8. Torque Reversal and Spin-Down of the Accretion-Powered Pulsar 4U 1626-67

    NASA Technical Reports Server (NTRS)

    Chakrabarty, Deepto L.; Bildsten, L.; Grunsfeld, J. M.; Koh, D. T.; Prince, T. A.; Vaughan, B. A.; Finger, M. H.; Scott, D. M.; Wilson, R. B.

    1997-01-01

    Over 5 yr of hard X-ray (20-60 keV) monitoring of the 7.66 s accretion-powered pulsar 4U 1626-67 with the Compton Gamma Ray Observatory/BATSE large-area detectors has revealed that the neutron star is now steadily spinning down, in marked contrast to the steady spin-up and spin-down torques differ by only 15% with the neutron star spin changing on a timescale |v/v| approximately equals 5000 yr in both states. The current spin-down rate is itself decreasing on a timescale |v/v| approximately equals 26 yr. The long-term timing history shows small-amplitude variations on a 4000 day timescale, which are probably due to variations in the mass transfer rate. The pulsed 20-60 keV emission from 4U 1626-67 is well-fitted by a power-law spectrum with photon index gamma = 4.9 and a typical pulsed intensity of 1.5 x 10(exp -10) ergs cm (exp -2)s(exp -1). The low count rates with BATSE prohibited us from constraining the reported 42 minute binary orbit, but we can rule out long-period orbits in the range 2 days < or = P(orb) < or = 900 days. We compare the long-term torque behavior of 4U 1626-67 to other disk-fed accreting pulsars and discuss the implications of our results for the various theories of magnetic accretion torques. The abrupt change in the sign of the torque is difficult to reconcile with the extremely smooth spin-down now observed. The strength of the torque noise in 4U 1626-67, approximately 10(exp -22) Hz(exp 2)s(exp -2) Hz(exp -1), is the smallest ever measured for an accreting X-ray pulsar, and it is comparable to the timing noise seen in young radio pulsars. We close by pointing out that the core temperature and external torque (the two parameters potentially relevant to internal sources of timing noise) of an accreting neutron star are also comparable to those of young radio pulsars.

  9. Comparing models of the periodic variations in spin-down and beamwidth for PSR B1828-11

    NASA Astrophysics Data System (ADS)

    Ashton, G.; Jones, D. I.; Prix, R.

    2016-05-01

    We build a framework using tools from Bayesian data analysis to evaluate models explaining the periodic variations in spin-down and beamwidth of PSR B1828-11. The available data consist of the time-averaged spin-down rate, which displays a distinctive double-peaked modulation, and measurements of the beamwidth. Two concepts exist in the literature that are capable of explaining these variations; we formulate predictive models from these and quantitatively compare them. The first concept is phenomenological and stipulates that the magnetosphere undergoes periodic switching between two metastable states as first suggested by Lyne et al. The second concept, precession, was first considered as a candidate for the modulation of B1828-11 by Stairs et al. We quantitatively compare models built from these concepts using a Bayesian odds ratio. Because the phenomenological switching model itself was informed by these data in the first place, it is difficult to specify appropriate parameter-space priors that can be trusted for an unbiased model comparison. Therefore, we first perform a parameter estimation using the spin-down data, and then use the resulting posterior distributions as priors for model comparison on the beamwidth data. We find that a precession model with a simple circular Gaussian beam geometry fails to appropriately describe the data, while allowing for a more general beam geometry provides a good fit to the data. The resulting odds between the precession model (with a general beam geometry) and the switching model are estimated as 102.7±0.5 in favour of the precession model.

  10. Constraining the Spin-down Timescale of the White Dwarf Progenitors of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Meng, Xiangcun; Podsiadlowski, Philipp

    2013-12-01

    Justham and Di Stefano et al. proposed that the white dwarf progenitor of a Type Ia supernova (SN Ia) may have to spin down before it can explode. As the white dwarf spin-down timescale is not well known theoretically, here we try to constrain it empirically (within the framework of this spin-down model) for progenitor systems that contain a giant donor and for which circumbinary material has been detected after the explosion: we obtain an upper limit of a few 107yr. Based on the study of Di Stefano & Kilic, this means that it is too early to rule out the existence of a surviving companion in SNR 0509-67.5.

  11. CONSTRAINING THE SPIN-DOWN TIMESCALE OF THE WHITE DWARF PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Meng, Xiangcun; Podsiadlowski, Philipp

    2013-12-01

    Justham and Di Stefano et al. proposed that the white dwarf progenitor of a Type Ia supernova (SN Ia) may have to spin down before it can explode. As the white dwarf spin-down timescale is not well known theoretically, here we try to constrain it empirically (within the framework of this spin-down model) for progenitor systems that contain a giant donor and for which circumbinary material has been detected after the explosion: we obtain an upper limit of a few 10{sup 7}yr. Based on the study of Di Stefano and Kilic, this means that it is too early to rule out the existence of a surviving companion in SNR 0509–67.5.

  12. Experiments on spin-up and spin-down on a beta-plane

    SciTech Connect

    Jillians, W.J.; Maxworthy, T.

    1994-07-01

    We study the spin-up and spin-down of a homogeneous fluid with a free surface on an experimental `beta-plane` and describe the important features for both cases over a range of parameters. Quantitative values are found for the velocity fields using a new image processing technique that analyses a video record of particle motion and stores the results digitally. Streamlines, pressure fields, and vorticity values are found by interpolation techniques and result in a complete description of the flow characteristics. We discuss the relationship between the results of these experiments and those observed in large-scale homogeneous models of ocean circulation, e.g. Moore. This study extends the work of van Heijst et al. to the case of spin-up in a rectangular container but of nonuniform depth and we note the differences to and similarities with their observations. It is related, also, to more recent results of Maas et al., who considered spin-up on a beta-plane but in a tank of very different proportions to the one considered here. 20 refs.

  13. Spin-up/spin-down of neutron star in Be-X-ray binary system GX 304-1

    NASA Astrophysics Data System (ADS)

    Postnov, K. A.; Mironov, A. I.; Lutovinov, A. A.; Shakura, N. I.; Kochetkova, A. Yu.; Tsygankov, S. S.

    2015-01-01

    We analyse spin-up/spin-down of the neutron star in Be-X-ray binary system GX 304-1 observed by Swift/X-ray telescope (XRT) and Fermi/gamma-ray burst monitor (GBM) instruments in the period of the source activity from 2010 April to 2013 January and discuss possible mechanisms of angular momentum transfer to/from the neutron star. We argue that the neutron star spin-down at quiescent states of the source with an X-ray luminosity of Lx ˜ 1034 erg s-1 between a series of Type I outbursts and spin-up during the outbursts can be explained by quasi-spherical settling accretion on to the neutron star. The outbursts occur near the neutron star periastron passages, where the density is enhanced due to the presence of an equatorial Be-disc tilted to the orbital plane. We also propose an explanation to the counterintuitive smaller spin-up rate observed at higher luminosity in a double-peak Type I outburst due to lower value of the specific angular momentum of matter captured from the quasi-spherical wind from the Be-star by the neutron star moving in an elliptical orbit with eccentricity e ≳ 0.5.

  14. THE SPIN-DOWN OF SWIFT J1822.3-1606: A NEW GALACTIC MAGNETAR

    SciTech Connect

    Livingstone, M. A.; Scholz, P.; Kaspi, V. M.; Ng, C.-Y.; Gavriil, Fotis P.

    2011-12-20

    On 2011 July 14, a new magnetar candidate, Swift J1822.3-1606, was identified via a rate trigger on the Swift/Burst Alert Telescope. Here we present an initial analysis of the X-ray properties of the source, using data from the Rossi X-ray Timing Explorer, Swift, and the Chandra X-ray Observatory, spanning 2011 July 16-October 8. We measure a precise spin period of P = 8.43771968(6) s and a spin-down rate of P-dot =2.54(22) Multiplication-Sign 10{sup -13}, at MJD 55761.0, corresponding to an inferred surface dipole magnetic field of B = 4.7(2) Multiplication-Sign 10{sup 13} G, the second lowest thus far measured for a magnetar, though similar to those of 1E 2259+586 and several high-magnetic field radio pulsars. We show that the flux decay in the 1-10 keV band is best fit by a double exponential with timescales of 9 {+-} 1 and 55 {+-} 9 days. The pulsed count rate decay in the 2-10 keV band, by contrast, is better fit by a single exponential decay with timescale 15.9 {+-} 0.2 days. After increasing from {approx}35% for {approx}20 days after the onset of the outburst, the pulsed fraction in the 2-10 keV band remained constant at {approx}45%. We argue that these properties confirm this source to be a new member of the class of objects known as magnetars. We consider the distribution of magnetar periods and inferred dipole magnetic field strengths, showing that the former appears flat in the 2-12 s range, while the latter appears peaked in the 10{sup 14}-10{sup 15} G range.

  15. CONSTRAINING THE SPIN-DOWN OF THE NEARBY ISOLATED NEUTRON STAR RX J0806.4-4123, AND IMPLICATIONS FOR THE POPULATION OF NEARBY NEUTRON STARS

    SciTech Connect

    Kaplan, D. L.; Van Kerkwijk, M. H. E-mail: mhvk@astro.utoronto.c

    2009-11-01

    The nearby isolated neutron stars (INSs) are a group of seven relatively slowly rotating neutron stars that show thermal X-ray spectra, most with broad absorption features. They are interesting both because they may allow one to determine fundamental neutron-star properties by modeling their spectra, and because they appear to be a large fraction of the overall neutron-star population. Here, we describe a series of XMM -Newton observations of the nearby INS RX J0806.4-4123, taken as part of larger program of timing studies. From these, we limit the spin-down rate to nu-dot=(-4.3+-2.3)x10{sub -16}Hz s{sup -1}. This constrains the dipole magnetic field to be <3.7 x 10{sup 13} G at 2sigma, significantly less than the field of approx10{sup 14} G implied by simple models for the X-ray absorption found at 0.45 keV. We confirm that the spectrum is thermal and stable (to within a few percent), but find that the 0.45 keV absorption feature is broader and more complex than previously thought. Considering the population of INSs, we find that magnetic field decay from an initial field of approx<3 x 10{sup 14} G accounts most naturally for their timing and spectral properties, both qualitatively and in the context of the models for field decay of Pons and collaborators.

  16. Spin Down of Pulsations in the Cooling Tail of an X-ray Burst from 4U 1636-53

    NASA Technical Reports Server (NTRS)

    Strohmayer, Tod E.

    1999-01-01

    We report the discovery with the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) of a decrease in the frequency of X-ray brightness oscillations in the cooling tail of an X-ray burst from 4U 1636-53. This is the first direct evidence for a spin down of the pulsations seen during thermonuclear bursts. We find that the spin down episode is correlated with the appearance in this burst of an extended tail of emission with a decay timescale much longer than is seen in other bursts from 4U 1636-53 in the same set of observations. We present both time resolved energy and variability spectra during this burst and compare them with results from a second burst which shows neither a spin down episode nor an extended tail. A spectral evolution study of the "spin down" burst reveals a secondary signature of weak radius expansion, not seen in other bursts, and correlated with the spin down episode, which may indicate a secondary thermonuclear energy release. We interpret the spin down episode in the context of an angular momentum conserving shell, which is reexpanded and therefore spun down by an additional thermonuclear energy release which could also explain the extended X-ray tail.

  17. Viscous pumping and the spin-down of thermospheric gyres and jets

    NASA Technical Reports Server (NTRS)

    Walterscheid, R. L.; Schubert, G.

    1986-01-01

    Strong gyres and jets can be generated at auroral latitudes in the thermosphere by enhanced electric fields during geomagnetic substorms. Typical height profiles of ion density suggest that the ion drag force should generate large curvature in the vertical profile of the winds in the highly viscous region of the thermosphere above about 200 km. It is proposed that the poststorm spin-down of these gyres and jets proceeds via Ekman circulations driven by the curvatures in the height profiles of the winds. Analytic and numerical calculations of the ageostrophic winds forced by curvature in model geostrophic wind profiles show that the ageostrophic wind speeds and directions depend mainly on the kinematic viscosity in the region of curvature and the total change in shear in the geostrophic wind. Ageostrophic wind speeds for typical thermospheric jets can exceed 200 m/s (about 50 percent of the jet winds). Spin-down times of thermospheric jets and cyclonic gyres by the Ekman pumping mechanism are estimated at less than about 6 hours.

  18. Spin-down of Pulsars, and Their Electromagnetic and Gravitational Wave Radiations

    NASA Astrophysics Data System (ADS)

    Yue-zhu, Zhang; Yan-yan, Fu; Yi-huan, Wei; Cheng-min, Zhang; Shao-hua, Yu; Yuan-yue, Pan; Yuan-qi, Guo; De-hua, Wang

    2016-04-01

    Pulsars posses extremely strong magnetic fields, and their magnetic axis does not coincide with their rotation axis, this causes the pulsars to emit electromagnetic radiations. Pulsars rely on their rotational energy to compensate for the energy loss caused by the electromagnetic radiation, which leads to the gradually decelerated spin of pulsars. According to the theoretical deduction, we have calculated the initial period of the Crab Nebula pulsar, and derived the period evolution of the pulsar at any time in the future under the effect of the electromagnetic radiation. Considered the possible existence of quadrupole moment in the mass distribution of a pulsar, the gravitational wave radiation will also make the pulsar spin down, hence the variation of spin period of the Crab pulsar under the effect of gravitational wave radiation is further analyzed. Finally, combining the two kinds of radiation mechanisms, the evolution of spin period of the Crab pulsar under the joint action of these two kinds of radiation mechanisms is analyzed.

  19. The long-term post-outburst spin down and flux relaxation of magnetar swift J1822.3–1606

    SciTech Connect

    Scholz, P.; Kaspi, V. M.; Cumming, A.

    2014-05-01

    The magnetar Swift J1822.3–1606 entered an outburst phase in 2011 July. Previous X-ray studies of its post-outburst rotational evolution yielded inconsistent measurements of the spin-inferred magnetic field. Here we present the timing behavior and flux relaxation from over two years of Swift, RXTE, and Chandra observations following the outburst. We find that the ambiguity in previous timing solutions was due to enhanced spin down that resembles an exponential recovery following a glitch at the outburst onset. After fitting out the effects of the recovery, we measure a long-term spin-down rate of ν-dot =(−3.0 ± 0.3)×10{sup −16} s{sup –2} which implies a dipolar magnetic field of 1.35 × 10{sup 13} G, lower than all previous estimates for this source. We also consider the post-outburst flux evolution, and fit it with both empirical and crustal cooling models. We discuss the flux relaxation in the context of both crustal cooling and magnetospheric relaxation models.

  20. Angular Momentum Transport in Magnetized Stellar Radiative Zones. II. The Solar Spin-down

    NASA Astrophysics Data System (ADS)

    Charbonneau, P.; MacGregor, K. B.

    1993-11-01

    We present a large set of numerical calculations describing the rotational evolution of a solar-type star, in response to the torque exerted on it by a magnetically coupled wind emanating from its surface. We consider a situation where the internal redistribution of angular momentum in the radiative part of the envelope is dominated by magnetic stresses arising from the shearing of a preexisting, large-scale, poloidal magnetic field. By assuming a time-independent poloidal magnetic field, neglecting fluid motions in meridional planes, and restricting our attention to axisymmetric systems, we reduce the spin-down problem to solving the (coupled) ψ-components of the momentum and induction equations. Nevertheless, our computations remain dynamical, in that they take into account both the generation of a toroidal magnetic field by shearing of the preexisting poloidal field, and the back-reaction of the resulting Lorentz force on the differential rotation. It becomes possible to draw, for the first time, a reasonably realistic and quantitative picture of the effects of large-scale internal magnetic fields on the main-sequence rotational evolution of solar-type stars. We perform spin-down calculations for a standard solar model, starting from the ZAMS and extending all the way to the solar age. The wind-induced surface torque is computed using the axisymmetric formulation of Weber & Davis (1967). We consider a number of poloidal magnetic field configurations which differ both in the degree of magnetic coupling between the convective envelope and radiative core and in average strength. The rotational evolution can be divided into three more or less distinct phases: an initial phase of toroidal field buildup in the radiative zone, lasting from a few times 104 to a few times 106 yr; a second period in which oscillations set up in the radiative zone during the first phase are damped; and a third period, lasting from an age of about 107 yr onward, characterized by a state of

  1. Separated spin-up and spin-down quantum hydrodynamics of degenerated electrons: Spin-electron acoustic wave appearance

    NASA Astrophysics Data System (ADS)

    Andreev, Pavel A.

    2015-03-01

    The quantum hydrodynamic (QHD) model of charged spin-1/2 particles contains physical quantities defined for all particles of a species including particles with spin-up and with spin-down. Different populations of states with different spin directions are included in the spin density (the magnetization). In this paper I derive a QHD model, which separately describes spin-up electrons and spin-down electrons. Hence electrons with different projections of spins on the preferable direction are considered as two different species of particles. It is shown that the numbers of particles with different spin directions do not conserve. Hence the continuity equations contain sources of particles. These sources are caused by the interactions of the spins with the magnetic field. Terms of similar nature arise in the Euler equation. The z projection of the spin density is no longer an independent variable. It is proportional to the difference between the concentrations of the electrons with spin-up and the electrons with spin-down. The propagation of waves in the magnetized plasmas of degenerate electrons is considered. Two regimes for the ion dynamics, the motionless ions and the motion of the degenerate ions as the single species with no account of the spin dynamics, are considered. It is shown that this form of the QHD equations gives all solutions obtained from the traditional form of QHD equations with no distinction of spin-up and spin-down states. But it also reveals a soundlike solution called the spin-electron acoustic wave. Coincidence of most solutions is expected since this derivation was started with the same basic equation: the Pauli equation. Solutions arise due to the different Fermi pressures for the spin-up electrons and the spin-down electrons in the magnetic field. The results are applied to degenerate electron gas of paramagnetic and ferromagnetic metals in the external magnetic field. The dispersion of the spin-electron acoustic waves in the partially spin

  2. Separated spin-up and spin-down quantum hydrodynamics of degenerated electrons: Spin-electron acoustic wave appearance.

    PubMed

    Andreev, Pavel A

    2015-03-01

    The quantum hydrodynamic (QHD) model of charged spin-1/2 particles contains physical quantities defined for all particles of a species including particles with spin-up and with spin-down. Different populations of states with different spin directions are included in the spin density (the magnetization). In this paper I derive a QHD model, which separately describes spin-up electrons and spin-down electrons. Hence electrons with different projections of spins on the preferable direction are considered as two different species of particles. It is shown that the numbers of particles with different spin directions do not conserve. Hence the continuity equations contain sources of particles. These sources are caused by the interactions of the spins with the magnetic field. Terms of similar nature arise in the Euler equation. The z projection of the spin density is no longer an independent variable. It is proportional to the difference between the concentrations of the electrons with spin-up and the electrons with spin-down. The propagation of waves in the magnetized plasmas of degenerate electrons is considered. Two regimes for the ion dynamics, the motionless ions and the motion of the degenerate ions as the single species with no account of the spin dynamics, are considered. It is shown that this form of the QHD equations gives all solutions obtained from the traditional form of QHD equations with no distinction of spin-up and spin-down states. But it also reveals a soundlike solution called the spin-electron acoustic wave. Coincidence of most solutions is expected since this derivation was started with the same basic equation: the Pauli equation. Solutions arise due to the different Fermi pressures for the spin-up electrons and the spin-down electrons in the magnetic field. The results are applied to degenerate electron gas of paramagnetic and ferromagnetic metals in the external magnetic field. The dispersion of the spin-electron acoustic waves in the partially spin

  3. Oblique propagation of longitudinal waves in magnetized spin-1/2 plasmas: Independent evolution of spin-up and spin-down electrons

    SciTech Connect

    Andreev, Pavel A. Kuz’menkov, L.S.

    2015-10-15

    We consider quantum plasmas of electrons and motionless ions. We describe separate evolution of spin-up and spin-down electrons. We present corresponding set of quantum hydrodynamic equations. We assume that plasmas are placed in an uniform external magnetic field. We account different occupation of spin-up and spin-down quantum states in equilibrium degenerate plasmas. This effect is included via equations of state for pressure of each species of electrons. We study oblique propagation of longitudinal waves. We show that instead of two well-known waves (the Langmuir wave and the Trivelpiece–Gould wave), plasmas reveal four wave solutions. New solutions exist due to both the separate consideration of spin-up and spin-down electrons and different occupation of spin-up and spin-down quantum states in equilibrium state of degenerate plasmas.

  4. ON THE SPIN-DOWN AND MAGNETIC FIELD OF THE X-RAY PULSAR 1E 1207.4-5209

    SciTech Connect

    Halpern, J. P.; Gotthelf, E. V. E-mail: eric@astro.columbia.edu

    2011-06-01

    We analyze all of the archival X-ray timing data from the years 2000-2008 on the weakly magnetized central compact object (CCO) pulsar 1E 1207.4-5209 in an attempt to measure its dipole magnetic field strength via spin-down. because most of these observations were not planned for the purpose of phase-coherent timing, the resulting ephemeris is not unique, but is restricted to two comparably good timing solutions that correspond to B{sub s} = 9.9 x 10{sup 10} G or 2.4 x 10{sup 11} G, respectively, assuming dipole spin-down. One of these should be the correct value and the other one an alias. There are no spinning-up solutions. The smaller value of B{sub s} is close to the surface field of 8 x 10{sup 10} G that is measured independently from the unique absorption lines in the X-ray spectrum of 1E 1207.4-5209, assuming that the lowest-energy line at 0.7 keV is the electron-cyclotron fundamental. We suggest that 1E 1207.4-5209 has the strongest magnetic field among CCOs, which would account for the unique presence of its cyclotron absorption spectrum, while other CCOs likely have even weaker fields for which the cyclotron fundamental falls below the observable soft X-ray band.

  5. X-Ray Measurement of the Spin-down of Calvera: A Radio- and Gamma-Ray-Quiet Pulsar

    NASA Astrophysics Data System (ADS)

    Halpern, J. P.; Bogdanov, S.; Gotthelf, E. V.

    2013-12-01

    We measure spin-down of the 59 ms X-ray pulsar Calvera by comparing the XMM-Newton discovery data from 2009 with new Chandra timing observations taken in 2013. Its period derivative is \\dot{P}=(3.19+/- \\,0.08)\\times 10^{-15}, which corresponds to spin-down luminosity \\dot{E}=6.1\\times 10^{35} erg s-1, characteristic age \\tau _c\\equiv P/2\\dot{P}=2.9\\times 10^5 yr, and surface dipole magnetic field strength Bs = 4.4 × 1011 G. These values rule out a mildly recycled pulsar, but Calvera could be an orphaned central compact object (anti-magnetar), with a magnetic field that was initially buried by supernova debris and is now reemerging and approaching normal strength. We also performed unsuccessful searches for high-energy γ-rays from Calvera in both imaging and timing of >100 MeV Fermi photons. Even though the distance to Calvera is uncertain by an order of magnitude, an upper limit of d < 2 kpc inferred from X-ray spectra implies a γ-ray luminosity limit of <3.3 × 1032 erg s-1, which is less than that of any pulsar of comparable \\dot{E}. Calvera shares some properties with PSR J1740+1000, a young radio pulsar that we show by virtue of its lack of proper motion was born outside of the Galactic disk. As an energetic, high-Galactic-latitude pulsar, Calvera is unique in being undetected in both radio and γ-rays to faint limits, which should place interesting constraints on models for particle acceleration and beam patterns in pulsar magnetospheres.

  6. Connecting Related Rates and Differential Equations

    ERIC Educational Resources Information Center

    Brandt, Keith

    2012-01-01

    This article points out a simple connection between related rates and differential equations. The connection can be used for in-class examples or homework exercises, and it is accessible to students who are familiar with separation of variables.

  7. Pulsar wind model for the spin-down behavior of intermittent pulsars

    SciTech Connect

    Li, L.; Tong, H.; Yan, W. M.; Yuan, J. P.; Wang, N.; Xu, R. X.

    2014-06-10

    Intermittent pulsars are part-time radio pulsars. They have higher slow down rates in the on state (radio-loud) than in the off state (radio-quiet). This gives evidence that particle wind may play an important role in pulsar spindown. The effect of particle acceleration is included in modeling the rotational energy loss rate of the neutron star. Applying the pulsar wind model to the three intermittent pulsars (PSR B1931+24, PSR J1841–0500, and PSR J1832+0029) allows their magnetic fields and inclination angles to be calculated simultaneously. The theoretical braking indices of intermittent pulsars are also given. In the pulsar wind model, the density of the particle wind can always be the Goldreich-Julian density. This may ensure that different on states of intermittent pulsars are stable. The duty cycle of particle wind can be determined from timing observations. It is consistent with the duty cycle of the on state. Inclination angle and braking index observations of intermittent pulsars may help to test different models of particle acceleration. At present, the inverse Compton scattering induced space charge limited flow with field saturation model can be ruled out.

  8. Angular momentum redistribution by mixed modes in evolved low-mass stars. II. Spin-down of the core of red giants induced by mixed modes

    NASA Astrophysics Data System (ADS)

    Belkacem, K.; Marques, J. P.; Goupil, M. J.; Mosser, B.; Sonoi, T.; Ouazzani, R. M.; Dupret, M. A.; Mathis, S.; Grosjean, M.

    2015-07-01

    The detection of mixed modes in subgiants and red giants by the CoRoT and Kepler space-borne missions allows us to investigate the internal structure of evolved low-mass stars, from the end of the main sequence to the central helium-burning phase. In particular, the measurement of the mean core rotation rate as a function of the evolution places stringent constraints on the physical mechanisms responsible for the angular momentum redistribution in stars. It showed that the current stellar evolution codes including the modelling of rotation fail to reproduce the observations. An additional physical process that efficiently extracts angular momentum from the core is thus necessary. Our aim is to assess the ability of mixed modes to do this. To this end, we developed a formalism that provides a modelling of the wave fluxes in both the mean angular momentum and the mean energy equations in a companion paper. In this article, mode amplitudes are modelled based on recent asteroseismic observations, and a quantitative estimate of the angular momentum transfer is obtained. This is performed for a benchmark model of 1.3 M⊙ at three evolutionary stages, representative of the evolved pulsating stars observed by CoRoT and Kepler. We show that mixed modes extract angular momentum from the innermost regions of subgiants and red giants. However, this transport of angular momentum from the core is unlikely to counterbalance the effect of the core contraction in subgiants and early red giants. In contrast, for more evolved red giants, mixed modes are found efficient enough to balance and exceed the effect of the core contraction, in particular in the hydrogen-burning shell. Our results thus indicate that mixed modes are a promising candidate to explain the observed spin-down of the core of evolved red giants, but that an other mechanism is to be invoked for subgiants and early red giants.

  9. A Laboratory Exercise with Related Rates.

    ERIC Educational Resources Information Center

    Sworder, Steven C.

    A laboratory experiment, based on a simple electric circuit that can be used to demonstrate the existence of real-world "related rates" problems, is outlined and an equation for voltage across the capacitor terminals during discharge is derived. The necessary materials, setup methods, and experimental problems are described. A student laboratory…

  10. Modeling the Multi-band Afterglow of GRB 130831A: Evidence for a Spinning-down Magnetar Dominated by Gravitational Wave Losses?

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Huang, Y. F.; Zong, H. S.

    2016-06-01

    The X-ray afterglow of GRB 130831A shows an “internal plateau” with a decay slope of ∼0.8, followed by a steep drop at around 105 s with a slope of ∼6. After the drop, the X-ray afterglow continues with a much shallower decay. The optical afterglow exhibits two segments of plateaus separated by a luminous optical flare, followed by a normal decay with a slope basically consistent with that of the late-time X-ray afterglow. The decay of the internal X-ray plateau is much steeper than what we expect in the simplest magnetar model. We propose a scenario in which the magnetar undergoes gravitational-wave-driven r-mode instability, and the spin-down is dominated by gravitational wave losses up to the end of the steep plateau, so that such a relatively steep plateau can be interpreted as the internal emission of the magnetar wind and the sharp drop can be produced when the magnetar collapses into a black hole. This scenario also predicts an initial X-ray plateau lasting for hundreds of seconds with an approximately constant flux which is compatible with observation. Assuming that the magnetar wind has a negligible contribution in the optical band, we interpret the optical afterglow as the forward shock emission by invoking the energy injection from a continuously refreshed shock following the prompt emission phase. It is shown that our model can basically describe the temporal evolution of the multi-band afterglow of GRB 130831A.

  11. Are ultralong gamma-ray bursts powered by black holes spinning down?

    NASA Astrophysics Data System (ADS)

    Nathanail, Antonios; Contopoulos, Ioannis

    2015-10-01

    Gamma-ray bursts (GRBs) are violent explosions, coming from cosmological distances. They are detected in gamma-rays (also X-rays, UV, optical, radio) almost every day, and have typical durations of a few seconds to a few minutes. Some GRBs have been reported with extraordinary durations of 104 s, the so-called ultralong GRBs. It has been debated whether these form a new distinct class of events or whether they are similar to long GRBs. According to Blandford & Znajek, the spin energy of a rotating black hole can be extracted electromagnetically, should the hole be endowed with a magnetic field supported by electric currents in a surrounding disc. We argue that this can be the case for the central engines of GRBs and we show that the duration of the burst depends on the magnetic flux accumulated on the event horizon of the black hole. We thus estimate the surface magnetic field of a possible progenitor star, and we conclude that an ultralong GRB may originate from a progenitor star with a relatively low magnetic field.

  12. Relation between gastric emptying rate and rate of intraluminal lipolysis.

    PubMed

    Maes, B D; Ghoos, Y F; Geypens, B J; Hiele, M I; Rutgeerts, P J

    1996-01-01

    The variable gastric emptying rate of a test meal is one of the major problems in evaluating accurately gastrointestinal physiological functions beyond the stomach. The aim of this study was to evaluate the effect of the gastric emptying rate on the rate of intraluminal lipolysis. Thirty four subjects without pancreatic disease (21 with a normal gastric emptying and 13 with a known slow gastric emptying) and 14 subjects with pancreatic disease (four without and 10 with pancreatic insufficiency) were studied using a dual labelled breath test. The test meal consisted of one egg, 60 grams of white bread, 10 grams of margarine, and 150 ml of water (350 kcal). The egg yolk was labelled with 91 mg of 13C-octanoic acid, the margarine was labelled with 296 kBq of distearyl-2-14C-octanoyl-glycerol. Breath samples were taken every 15 minutes during six hours and analysed for 13CO2 and 14CO2 content. The gastric emptying rate of the meal was evaluated by the gastric emptying coefficient, the half emptying time, and the lag phase; the rate of intraluminal lipolysis was evaluated by the six hours cumulative 14CO2 excretion. Despite a clear distinction in the rate of intraluminal lipolysis, no difference could be detected in gastric emptying rate of the test meal between subjects without and with pancreatic disease. In subjects with pancreatic insufficiency, intraluminal hydrolysis was the rate limiting process in fat assimilation; in patients without pancreatic insufficiency, however, gastric emptying could be rate limiting. Therefore, patients with known slow gastric emptying, displayed a significantly decreased rate of intraluminal lipolysis compared with normal controls. This decrease could be corrected for accurately using a correction factor based on the gastric emptying coefficient. In conclusion, the combined 13C-octanoic acid and 14C-mixed triglyceride breath test permits the measurement of gastric emptying rate and intraluminal lipolysis simultaneously in a minimally

  13. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1988-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more that 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  14. On relative supernova rates and nucleosynthesis roles

    NASA Technical Reports Server (NTRS)

    Arnett, W. David; Schramm, David N.; Truran, James W.

    1989-01-01

    It is shown that the Ni-56-Fe-56 observed in SN 1987A argues that core collapse supernovae may be responsible for more than 50 percent of the iron in the galaxy. Furthermore it is argued that the time averaged rate of thermonuclear driven Type I supernovae may be at least an order of magnitude lower than the average rate of core collapse supernovae. The present low rate of Type II supernovae (below their time averaged rate of approx. 1/10 yr) is either because the past rate was much higher because many core collapse supernovae are dim like SN 1987A. However, even in this latter case they are only an order of magnitude dimmer that normal Type II's due to the contribution of Ni-56 decay to the light curve.

  15. Feedback Functions, Optimization, and the Relation of Response Rate to Reinforcer Rate

    ERIC Educational Resources Information Center

    Soto, Paul L.; McDowell, Jack J.; Dallery, Jesse

    2006-01-01

    The present experiment arranged a series of inverted U-shaped feedback functions relating reinforcer rate to response rate to test whether responding was consistent with an optimization account or with a one-to-one relation of response rate to reinforcer rate such as linear system theory's rate equation or Herrnstein's hyperbola. Reinforcer rate…

  16. "Molecular Clock" Analogs: A Relative Rates Exercise

    ERIC Educational Resources Information Center

    Wares, John P.

    2008-01-01

    Although molecular clock theory is a commonly discussed facet of evolutionary biology, undergraduates are rarely presented with the underlying information of how this theory is examined relative to empirical data. Here a simple contextual exercise is presented that not only provides insight into molecular clocks, but is also a useful exercise for…

  17. Separated spin-up and spin-down evolution of degenerated electrons in two-dimensional systems: Dispersion of longitudinal collective excitations in plane and nanotube geometry

    NASA Astrophysics Data System (ADS)

    Andreev, Pavel A.; Kuz'menkov, L. S.

    2016-01-01

    Applying the separated spin evolution quantum hydrodynamics to the two-dimensional electron gas in plane samples and nanotubes located in external magnetic fields we have found a novel type of waves in the electron gas which is called spin-electron acoustic wave. A separate spin-up and spin-down electrons' evolution reveals the replacement of the Langmuir wave by a pair of hybrid waves. One of the two hybrid waves is a modified Langmuir wave. Another hybrid wave is a spin-electron acoustic wave. We studied the dispersion of these waves in two-dimensional structures of electrons. We also considered the dependence of dispersion properties on spin polarization of electrons in an external magnetic field.

  18. X-ray measurement of the spin-down of CalverA: A radio- and gamma-ray-quiet pulsar

    SciTech Connect

    Halpern, J. P.; Bogdanov, S.; Gotthelf, E. V.

    2013-12-01

    We measure spin-down of the 59 ms X-ray pulsar Calvera by comparing the XMM-Newton discovery data from 2009 with new Chandra timing observations taken in 2013. Its period derivative is P-dot =(3.19± 0.08)×10{sup −15}, which corresponds to spin-down luminosity E-dot =6.1×10{sup 35} erg s{sup –1}, characteristic age τ{sub c}≡P/2 P-dot =2.9×10{sup 5} yr, and surface dipole magnetic field strength B{sub s} = 4.4 × 10{sup 11} G. These values rule out a mildly recycled pulsar, but Calvera could be an orphaned central compact object (anti-magnetar), with a magnetic field that was initially buried by supernova debris and is now reemerging and approaching normal strength. We also performed unsuccessful searches for high-energy γ-rays from Calvera in both imaging and timing of >100 MeV Fermi photons. Even though the distance to Calvera is uncertain by an order of magnitude, an upper limit of d < 2 kpc inferred from X-ray spectra implies a γ-ray luminosity limit of <3.3 × 10{sup 32} erg s{sup –1}, which is less than that of any pulsar of comparable E-dot . Calvera shares some properties with PSR J1740+1000, a young radio pulsar that we show by virtue of its lack of proper motion was born outside of the Galactic disk. As an energetic, high-Galactic-latitude pulsar, Calvera is unique in being undetected in both radio and γ-rays to faint limits, which should place interesting constraints on models for particle acceleration and beam patterns in pulsar magnetospheres.

  19. What Factors Shape "by" Ratings in Relation to Landmarks?

    ERIC Educational Resources Information Center

    Hund, Alycia M.

    2010-01-01

    Two experiments investigated how absolute and relative distance shape adults' and young children's ratings concerning the extent to which the term "by" describes the relation between locations. Three- and 4-year-old children and adults were asked to rate how well the word "by" described the relation between several blocks and a landmark. The…

  20. A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster.

    PubMed

    Meibom, Søren; Barnes, Sydney A; Platais, Imants; Gilliland, Ronald L; Latham, David W; Mathieu, Robert D

    2015-01-29

    The ages of the most common stars--low-mass (cool) stars like the Sun, and smaller--are difficult to derive because traditional dating methods use stellar properties that either change little as the stars age or are hard to measure. The rotation rates of all cool stars decrease substantially with time as the stars steadily lose their angular momenta. If properly calibrated, rotation therefore can act as a reliable determinant of their ages based on the method of gyrochronology. To calibrate gyrochronology, the relationship between rotation period and age must be determined for cool stars of different masses, which is best accomplished with rotation period measurements for stars in clusters with well-known ages. Hitherto, such measurements have been possible only in clusters with ages of less than about one billion years, and gyrochronology ages for older stars have been inferred from model predictions. Here we report rotation period measurements for 30 cool stars in the 2.5-billion-year-old cluster NGC 6819. The periods reveal a well-defined relationship between rotation period and stellar mass at the cluster age, suggesting that ages with a precision of order 10 per cent can be derived for large numbers of cool Galactic field stars. PMID:25539085

  1. A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster

    NASA Astrophysics Data System (ADS)

    Meibom, Søren; Barnes, Sydney A.; Platais, Imants; Gilliland, Ronald L.; Latham, David W.; Mathieu, Robert D.

    2015-01-01

    The ages of the most common stars--low-mass (cool) stars like the Sun, and smaller--are difficult to derive because traditional dating methods use stellar properties that either change little as the stars age or are hard to measure. The rotation rates of all cool stars decrease substantially with time as the stars steadily lose their angular momenta. If properly calibrated, rotation therefore can act as a reliable determinant of their ages based on the method of gyrochronology. To calibrate gyrochronology, the relationship between rotation period and age must be determined for cool stars of different masses, which is best accomplished with rotation period measurements for stars in clusters with well-known ages. Hitherto, such measurements have been possible only in clusters with ages of less than about one billion years, and gyrochronology ages for older stars have been inferred from model predictions. Here we report rotation period measurements for 30 cool stars in the 2.5-billion-year-old cluster NGC 6819. The periods reveal a well-defined relationship between rotation period and stellar mass at the cluster age, suggesting that ages with a precision of order 10 per cent can be derived for large numbers of cool Galactic field stars.

  2. Relation of managers' personality to accident and injury rates.

    PubMed

    Thoms, Peg; Venkataraman, Ray R

    2002-12-01

    Previous research has explored the link between certain aspects of individuals' personalities and their safety behavior and accident rates. We predicted a relation between 23 managers' scores on Big Five personality dimensions and departmental accident and injury rates in a manufacturing company. Accident and injury data were provided by the organization. We found a relation between managers' personality profiles and both injury and accident rates in their departments. The findings suggest that managers with certain types of personalities may have safer work units. This has implications for the selection of managers in work environments with safety risks. PMID:12585521

  3. Broad-band modelling of short gamma-ray bursts with energy injection from magnetar spin-down and its implications for radio detectability

    NASA Astrophysics Data System (ADS)

    Gompertz, B. P.; van der Horst, A. J.; O'Brien, P. T.; Wynn, G. A.; Wiersema, K.

    2015-03-01

    The magnetar model has been proposed to explain the apparent energy injection in the X-ray light curves of short gamma-ray bursts (SGRBs), but its implications across the full broad-band spectrum are not well explored. We investigate the broad-band modelling of four SGRBs with evidence for energy injection in their X-ray light curves, applying a physically motivated model in which a newly formed magnetar injects energy into a forward shock as it loses angular momentum along open field lines. By performing an order of magnitude search for the underlying physical parameters in the blast wave, we constrain the characteristic break frequencies of the synchrotron spectrum against their manifestations in the available multiwavelength observations for each burst. The application of the magnetar energy injection profile restricts the successful matches to a limited family of models that are self-consistent within the magnetic dipole spin-down framework. We produce synthetic light curves that describe how the radio signatures of these SGRBs ought to have looked given the restrictions imposed by the available data, and discuss the detectability of these signatures with present-day and near-future radio telescopes. Our results show that both the Atacama Large Millimeter Array (ALMA) and the upgraded Very Large Array are now sensitive enough to detect the radio signature within two weeks of trigger in most SGRBs, assuming our sample is representative of the population as a whole. We also find that the upcoming Square Kilometre Array will be sensitive to depths greater than those of our lower limit predictions.

  4. Component duration and relative response rates in multiple schedules.

    NASA Technical Reports Server (NTRS)

    Todorov, J. C.

    1972-01-01

    Pigeons were trained on a multiple variable-interval 30-sec, variable interval 90-sec schedule with each component presented alternately for an equal duration. This duration of exposure was varied from 5 to 300 sec. The rate of response in the variable-interval 30-sec component relative to the rate of response in the variable-interval 90-sec component was studied. Results are plotted and discussed.

  5. Pulse Phase Dependence of Low Energy Emission Lines in an X-ray pulsar 4U 1626-67 during its spin-up and spin-down phase

    NASA Astrophysics Data System (ADS)

    Beri, Aru; Paul, Biswajit; Dewangan, Gulab Chand

    2016-07-01

    We will present the results obtained from the new observation of an ultra-compact X-ray binary pulsar 4U 1626-67, carried out with the XMM-Newton observatory. 4U 1626-67, a unique accretion powered pulsar underwent two torque reversals since its discovery in 1977. Pulse phase resolved spectroscopy of this source performed using the data from the XMM-Newton observatory during its spin-down phase revealed the dependence of the emission lines on the pulse phase. O VII emission line at 0.569 keV showed the maximum variation by factor of 4. These variations were interpreted due to warps in the accretion disk (Beri et al. 2015). Radiation pressure induced warping is also believed to be the cause for spin-down. In light of this possible explanation for spin-down torque reversal we expect different line variability during the spin-up phase. We will discuss the implications of the results obtained after performing pulse phase resolved spectroscopy using data from the EPIC-pn during the current spin-up phase. Detailed study of the prominent Neon and Oxygen line complexes with the high resolution Reflection Grating Spectrometer (RGS) on-board XMM-Newton will also be presented.

  6. Do Dogs Know Related Rates Rather than Optimization?

    ERIC Educational Resources Information Center

    Perruchet, Pierre; Gallego, Jorge

    2006-01-01

    Although dogs seemingly follow the optimal path where they get to a ball thrown into the water, they certainly do not know the minimization function proposed in the calculus books. Trading the optimization problem for a related rates problem leads to a mathematically identical solution, which, it is argued here, is a more plausible model for the…

  7. Relative cooling rates derived from basalt column geometries

    NASA Astrophysics Data System (ADS)

    Woodell, Daniel; Porritt, Lucy; Russell, Kelly

    2015-04-01

    Columnar joints form as a brittle relaxation response to tensile stresses that accumulate during cooling of lava flows, pyroclastic deposits, and intrusive magma bodies. Columnar jointing forms in different deposit types, in deposits of different compositions, and different outcrop geometries. Despite this diversity, columns follow a few "rules": column diameter is inversely proportional to cooling rate (small/quick cooling times, small diameter columns), columns only ever coalesce (never bifurcate), and columnar joints always propagate parallel to but in the opposite direction of heat flow (towards the hottest part of the flow). Using these "rules," cooling histories and emplacement environments can be reconstructed. While column geometries and definitions of various columnar structures vary between authors (upper and lower colonnade and entablature vs. master cracks and pseudopillows), this study focuses on relatively simple outcrops of basalt lava within the Cheakamus River valley near Whistler, BC, Canada. The basalt lavas described here, thought to have erupted subglacially, contain columns comprising only well-defined upper and lower colonnades (i.e., no entablature). Comparing the relative thicknesses of upper and lower colonnades reveals the cooling history, relative cooling rates, and amounts of heat transferred from the upper and lower flow boundaries. Forward numerical models using the finite element method are created with Matlab using the Partial Differential Equation Toolbox to model the outcrops in the Whistler field area, and determine the cooling rates and thermal gradients experienced by the lava flows during their formation. This study finds that noticeable differences in the thickness of upper and lower colonnades within an outcrop occur only when there are large differences in cooling rates between the upper and lower flow surfaces. Modeling shows that the cooling rates must differ by approximately an order of magnitude to produce the observed

  8. Sensitivity to relative reinforcer rate in concurrent schedules: independence from relative and absolute reinforcer duration.

    PubMed Central

    McLean, A P; Blampied, N M

    2001-01-01

    Twelve pigeons responded on two keys under concurrent variable-interval (VI) schedules. Over several series of conditions, relative and absolute magnitudes of reinforcement were varied. Within each series, relative rate of reinforcement was varied and sensitivity of behavior ratios to reinforcer-rate ratios was assessed. When responding at both alternatives was maintained by equal-sized small reinforcers, sensitivity to variation in reinforcer-rate ratios was the same as when large reinforcers were used. This result was observed when the overall rate of reinforcement was constant over conditions, and also in another series of concurrent schedules in which one schedule was kept constant at VI ached 120 s. Similarly, reinforcer magnitude did not affect the rate at which response allocation approached asymptote within a condition. When reinforcer magnitudes differred between the two responses and reinforcer-rate ratios were varied, sensitivity of behavior allocation was unaffected although response bias favored the schedule that arranged the larger reinforcers. Analysis of absolute response rates ratio sensitivity to reinforcement occurrred on the two keys showed that this invariance of response despite changes in reinforcement interaction that were observed in absolute response rates on the constant VI 120-s schedule. Response rate on the constant VI 120-s schedule was inversely related to reinforcer rate on the varied key and the strength of this relation depended on the relative magnitude of reinforcers arranged on varied key. Independence of sensitivity to reinforcer-rate ratios from relative and absolute reinforcer magnitude is consistent with the relativity and independence assumtions of the matching law. PMID:11256865

  9. Simple relations between mean passage times and Kramers' stationary rate

    SciTech Connect

    Boilley, David; Jurado, Beatriz; Schmitt, Christelle

    2004-11-01

    The classical problem of the escape time of a metastable potential well in a thermal environment is generally studied by various quantities like Kramers' stationary escape rate, mean first passage time, nonlinear relaxation time, or mean last passage time. In addition, numerical simulations lead to the definition of other quantities as the long-time limit escape rate and the transient time. In this paper, we propose some simple analytical relations between all these quantities. In particular, we point out the hypothesis used to evaluate these various times in order to clarify their comparison and applicability, and show how average times include the transient time and the long-time limit of the escape rate.

  10. Reproductive Rates in Australian Rodents Are Related to Phylogeny

    PubMed Central

    Geffen, Eli; Rowe, Kevin C.; Yom-Tov, Yoram

    2011-01-01

    Background The native rodents of Australia are commonly divided into two groups based on the time of their colonization of the Sahulian continent, which encompasses Australia, New Guinea, and the adjacent islands. The first group, the “old endemics,” is a diverse assemblage of 34 genera that are descended from a single colonization of the continent during the Pliocene. A second group, the “new endemics,” is composed of several native Rattus species that are descended from a single colonization during the Pleistocene. Finally, a third group is composed of three non-native species of Rattus and Mus introduced into Australia by humans over the last 200 years. Previous studies have claimed that the three groups differ in their reproductive rates and that this variation in rates is associated with the unique environmental conditions across Australia. We examined these hypotheses using phylogenetically controlled methods. Methodology and Results We examined the relationship between the reproductive rates of the Australian rodents and the environmental variations across the continent, as well as the epoch of their colonization of the continent. Our results revealed no significant correlation with environmental variables but a significant association between colonization age and all the reproductive parameters examined. Discussion Based on a larger phylogeny of the subfamily Murinae, we showed that significant differences in reproductive rates among colonization groups are shared with their closest relatives outside Sahul. Therefore, the lower reproductive rates in the old endemics are more likely to be the result of phylogenetic history and conservation of traits than an adaptation to the Australian environment. In the new endemics, we found a trend of increasing reproductive rates with diversification. We suggest that the differences in reproductive rates of the old endemic rodents and the native Rattus represent alternative adaptive strategies that have allowed

  11. SHAPING THE DUST MASS-STAR-FORMATION RATE RELATION

    SciTech Connect

    Hjorth, Jens; Gall, Christa; Michałowski, Michał J. E-mail: cgall@phys.au.dk

    2014-02-20

    There is a remarkably tight relation between the observationally inferred dust masses and star-formation rates (SFRs) of Sloan Digital Sky Survey galaxies, M {sub dust} ∝ SFR{sup 1.11}. Here we extend the M {sub dust}-SFR relation to the high end and show that it bends over at very large SFRs (i.e., dust masses are lower than predicted for a given SFR). We identify several distinct evolutionary processes in the diagram: (1) a star-bursting phase in which dust builds up rapidly at early times. The maximum attainable dust mass in this process is the cause of the bend-over of the relation. A high dust-formation efficiency, a bottom-light initial mass function, and negligible supernova shock dust destruction are required to produce sufficiently high dust masses. (2) A quiescent star-forming phase in which the subsequent parallel decline in dust mass and SFR gives rise to the M {sub dust}-SFR relation, through astration and dust destruction. The dust-to-gas ratio is approximately constant along the relation. We show that the power-law slope of the M {sub dust}-SFR relation is inversely proportional to the global Schmidt-Kennicutt law exponent (i.e., ∼0.9) in simple chemical evolution models. (3) A quenching phase which causes star formation to drop while the dust mass stays roughly constant or drops proportionally. Combined with merging, these processes, as well as the range in total baryonic mass, give rise to a complex population of the diagram which adds significant scatter to the original M {sub dust}-SFR relation. (4) At very high redshifts, a population of galaxies located significantly below the local relation is predicted.

  12. Relative survival rates after alternative therapies for uveal melanoma

    SciTech Connect

    Seddon, J.M.; Gragoudas, E.S.; Egan, K.M.; Glynn, R.J.; Howard, S.; Fante, R.G.; Albert, D.M. )

    1990-06-01

    Survival in a group of 556 patients with uveal melanoma treated by proton beam irradiation with a median follow-up of 5.3 years was compared with that of 238 patients enucleated during the same 10-year period as irradiated patients (July 1975 to December 1984) with a median follow-up of 8.8 years, and 257 patients enucleated during the preceding 10 years (January 1965 to June 1975) with a median follow-up of 17.0 years. Adjustments were made for known prognostic factors including age, tumor location, tumor height, and clinical estimate of tumor diameter (for enucleated patients this was estimated in a regression equation relating histologic to clinical measurement). The overall rate ratio for all cause mortality was 1.2 (95% confidence interval, 0.9-1.6) for the concurrent enucleation series versus proton beam, and 1.6 (95% confidence interval, 1.2-2.1) for the earlier enucleation series versus proton beam. Relative rates of metastatic death, cancer death, and all cause mortality comparing alternative treatments were found to vary with time after treatment. Interval-specific rate ratios were evaluated using proportional hazards models fitted to separate time intervals after treatment. For all three outcomes, rate ratios were over two and statistically significant for the first 2 years after treatment and closer to one and nonsignificant after year 6 comparing the two enucleation groups with proton beam. Results suggest that treatment choice has little overall influence on survival in patients with uveal melanoma.

  13. The Determination of Relative Elemental Growth Rate Profiles from Segmental Growth Rates (A Methodological Evaluation).

    PubMed Central

    Peters, W. S.; Bernstein, N.

    1997-01-01

    Relative elemental growth rate (REGR) profiles describe spatial patterns of growth intensity; they are indispensable for causal growth analyses. Published methods of REGR profile determination from marking experiments fall in two classes: the profile is either described by a series of segmental growth rates, or calculated as the slope of a function describing the displacement velocities of points along the organ. The latter technique is usually considered superior for theoretical reasons, but to our knowledge, no comparative methodological study of the two approaches is currently available. We formulated a model REGR profile that resembles those reported from primary roots. We established the displacement velocity profile and derived growth trajectories, which enabled us to perform hypothetical marking experiments on the model with varying spacing of marks and durations of measurement. REGR profiles were determined from these data by alternative methods, and results were compared to the original profile. We find that with our model plotting of segmental relative growth rates versus segment position provides exact REGR profile estimations, if the initial segment length is less than 10% of the length of the whole growing zone, and if less than 20% of the growing zone is displaced past its boundary during the measurement. Based on our analysis, we discuss systematic errors that occur in marking experiments. PMID:12223680

  14. Relating Productivity Events to Holocene Bivalve Shell Growth Rates

    NASA Astrophysics Data System (ADS)

    Huntley, J. W.; Krause, R. A.; Kowalewski, M.; Romanek, C. S.; Kaufman, D. S.; Simoes, M. G.

    2007-12-01

    The growth rate of a bivalve can be influenced by many environmental factors that can change during the life of the organism. In this contribution we present initial data from a millennium scale chronology to assess the relationship between ontogenetic growth in the bivalve Semele casali and paleoenvironmental conditions preserved in the shell using growth increment analysis, radiocarbon-calibrated amino acid racemization dating techniques, stable isotopes (C and O) and high spatial resolution (125-150 samples per cm of shell profile) trace element (Ba, Mn) analysis (LA-ICPMS). Time-averaged specimens of S. casali were dredged from two sites at 10 meters and 30 meters depth along the inner continental shelf at Ubatuba Bay in the Southeast Brazilian Bight, an area influenced by productivity pulses triggered by coastal runoff events and coastal upwelling. Seventy-five individual valves were dated using amino acid racemization (aspartic acid). Dates were calculated using an expanded version of a previously published relationship (Barbour Wood et al., 2006 Quaternary Research 323- 331) between aspartic acid ratios and AMS radiocarbon dates of twelve S. casali individuals from the same sampling locations. The resulting time series has complete coverage for the past three thousand years at centennial resolution. From this time series, a sub-sample of dated valves was selected for more detailed growth increment, stable isotope and high-resolution trace element (Ba/Ca and Mn/Ca) analyses. Oceanic productivity is expressed differentially in the trace element profiles of S. casali with elevated Ba/Ca and Mn/Ca ratios capturing nutrient input through coastal runoff events while elevated Ba/Ca and depressed Mn/Ca ratios represent input through coastal upwelling. Fluctuations in Ba/Ca and Mn/Ca are not correlated to fluctuations in relative growth throughout the ontogeny of an individual bivalve, nor are they expected to be as periods of increased productivity are transient

  15. Age related flow rate nomograms in a normal pediatric population.

    PubMed

    Gaum, L D; Wese, F X; Liu, T P; Wong, A K; Hardy, B E; Churchill, B M

    1989-01-01

    Uroflow studies in a normal pediatric population were analysed statistically. Single studies for 511 subjects (272 boys and 239 girls) were reviewed. Nomograms relating peak flow to volume voided and age were established. An acceptable lower limit for peak flow was obtained from the data and a volume voided range was calculated so that both criteria could be used with 90% probability to define the normal voiding situation. The mean values of peak flow rate increased with volume voided in both sexes and also with age in the male population. Different sets of nomograms, which are necessary for daily clinical evaluation, are given. They define the normal values in the normal population. PMID:2763925

  16. The effect of relative update rates on tracking performance

    NASA Astrophysics Data System (ADS)

    Rea, Charles; Silbert, Mark

    2011-06-01

    In multi-sensor fusion applications, various sources of data are combined to create a coherent situational picture. The ability to track multiple targets using multiple sensors is an important problem. The data provided by these sensors can be of varying quality, such as data from RADAR and AIS. Does this varied quality of data negatively impact the tracking performance when compared to using the best data source alone? From an information-theoretic standpoint, the answer would be no. However, this paper investigates this issue and exposes a few caveats. In particular, this study addresses how the relative update rate of varying quality sensors affects tracking performance and answers the question 'Is more data always better?'

  17. Human heart rate variability relation is unchanged during motion sickness

    NASA Technical Reports Server (NTRS)

    Mullen, T. J.; Berger, R. D.; Oman, C. M.; Cohen, R. J.

    1998-01-01

    In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (ILV) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of ILV and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of ILV to HR transfer functions from the three conditions, we were unable to demonstrate a change in autonomic control of heart rate due to rotation alone or due to motion sickness. These findings do not support the notion that moderate motion sickness is manifested as a generalized autonomic response.

  18. An Optimal Relation of Radar Reflectivity to Lightning Rate

    NASA Technical Reports Server (NTRS)

    Heckman, S.

    1999-01-01

    Thunderstorms separate charge. Most places they lift positive charge or lower negative, a few places they lift negative or lower positive. The electrical generator is stronger in some parts of the cloud than in others. Our long term goal is to map this generator. Cloud physicists tell us that uncharged ice and water particles become charged by collision, and that the charge transferred depends on size, temperature and humidity. There is still some disagreement about exactly how the charge transferred depends on size, temperature, and humidity. In principle, if we knew this ice physics, and also knew the distribution of particles everywhere in the storm, and the winds everywhere and the temperature and humidity everywhere, then we could compute everywhere the electrical power of the thunderstorm generator. In practice it is difficult to know all these things, particularly the distribution of particles, so it is difficult to use real thunderstorms to falsify cloud electrification theories. We here take one small step towards computing that map of electrical generator power, by relating radar reflectivity profiles of 2000 storms to lightning flash rates of those storms. This small step by itself doesn't falsify any existing electrification theories; it merely places weak constraints on the relation of electric generator power to cloud ice.

  19. Florida submergence curve revised: Its relation to coastal sedimentation rates

    USGS Publications Warehouse

    Scholl, D. W.; Craighead, F.C., Sr.; Stuiver, M.

    1969-01-01

    New data substantiate as well as modify the south Florida submergence curve, which indicates that eustatic sea level has risen continuously, although at a generally decreasing rate, during the last 6500 to 7000 sidereal years (5500 standard radiocarbon years) to reach its present position. Accumulation rates of coastal deposits are similar to the rate of sea-level rise, thus supporting the generalization that submergence rates largely determine as well as limit rates of coastal sedimentation in lagoonal and estuarine areas.

  20. Omphacite breakdown reactions and relation to eclogite exhumation rates

    NASA Astrophysics Data System (ADS)

    Anderson, Eric D.; Moecher, David P.

    2007-09-01

    Clinopyroxene + plagioclase (±Hbl ± Qtz) symplectites after omphacite are widely cited as evidence for prior eclogite-facies or high-pressure (HP) metamorphism. Precursor omphacite compositions of retrograde eclogites, used for reconstructing retrograde P- T paths, are commonly estimated by reintegrating symplectite phases with the assumption that the symplectite-forming reactions were isochemical. Comparisons of broadbeam symplectite compositions to adjacent unreacted pyroxene from various symplectites after clinopyroxene from the Appalachian Blue Ridge (ABR) and Western Gneiss Region (WGR) suggest that the symplectite forming reactions are largely isochemical. Endmember calculations based on reintegrated symplectite compositions from the ABR and WGR suggest that a minor Ca-Eskola (CaEs) component (XCaEs = 0.04-0.15) was present in precursor HP clinopyroxene. WGR symplectites consist of fine-grained (˜1 μm-scale), vermicular intergrowths of Pl + Cpx II ± Hbl that occur at grain boundaries or internally. ABR symplectites contain coarser (˜10 μm-scale) planar lamellae and rods of Pl + Cpx II + Qtz + Hbl within clinopyroxene cores. The contrasting textures correlate with decompression and cooling rate, and degree of overstepping of the retrograde reaction (lamellar: slow, erosionally controlled exhumation with slow/low overstepping; fine-grained, grainboundary symplectite: rapid, tectonic exhumation with rapid/high overstepping). Variations in XCaEs, Xjd, and XCaTs of precursor HP omphacite are related to the symplectic mineral assemblages that result from decompression. Quartz-normative symplectities indicate quartz-producing retrograde reactions (e.g., breakdown of precursor CaEs); quartz-free symplectities (e.g., diopside + plagioclase after omphacite) indicate quartz-consuming reactions (jd, CaTs breakdown) outpaced quartz-producing reactions.

  1. Emergent relation between surface vapor conductance and relative humidity profiles yields evaporation rates from weather data

    PubMed Central

    Salvucci, Guido D.; Gentine, Pierre

    2013-01-01

    The ability to predict terrestrial evapotranspiration (E) is limited by the complexity of rate-limiting pathways as water moves through the soil, vegetation (roots, xylem, stomata), canopy air space, and the atmospheric boundary layer. The impossibility of specifying the numerous parameters required to model this process in full spatial detail has necessitated spatially upscaled models that depend on effective parameters such as the surface vapor conductance (Csurf). Csurf accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of Csurf to measured E, or further parameterization based on metrics such as leaf area, senescence state, stomatal conductance, soil texture, soil moisture, and water table depth. Here, we show that this key, rate-limiting, parameter can be estimated from an emergent relationship between the diurnal cycle of the relative humidity profile and E. The relation is that the vertical variance of the relative humidity profile is less than would occur for increased or decreased evaporation rates, suggesting that land–atmosphere feedback processes minimize this variance. It is found to hold over a wide range of climate conditions (arid–humid) and limiting factors (soil moisture, leaf area, energy). With this relation, estimates of E and Csurf can be obtained globally from widely available meteorological measurements, many of which have been archived since the early 1900s. In conjunction with precipitation and stream flow, long-term E estimates provide insights and empirical constraints on projected accelerations of the hydrologic cycle. PMID:23576717

  2. Unemployment Rate, Smoking in China: Are They Related?

    PubMed Central

    Wang, Qing; Shen, Jay J.; Cochran, Chris

    2016-01-01

    Background: Studies on the relationship between unemployment rate and smoking have yielded mixed results. The issue in China has not been studied. This study aims to examine the influence of unemployment rate on smoking in China. Methods: Logit model and two-stage least squares (2SLS) estimation were used to estimate the effects. Estimations were done for 4585 individual over 45 using data from China Health and Retirement Longitudinal Study conducted in Zhejiang and Gansu provinces in 2008 and 2012. Results: A percent increase in the unemployment rate resulted in the increase in the likelihood of smoking by a combined 9.1 percent for those who smoked including a 2.9% increase for those who smoked 1–10 cigarettes per day; a 2.8% increase for those who smoked 11–20 cigarettes per day; and a 3.4% increase for those who smoked 20 cigarettes or more per day. The effects were stronger for those who were employed. Non-drinkers were more likely to engage in smoking with increased unemployment rate. 2SLS estimation revealed the same association. Conclusions: The unemployment rate was positively associated with smoking behavior. Smoking control and intervention strategies should focus on both the individual′s characteristics and the physical environment in which unemployment rate tend to rise. PMID:26761019

  3. Age-Related Differences in Speech Rate Perception Do Not Necessarily Entail Age-Related Differences in Speech Rate Use

    ERIC Educational Resources Information Center

    Heffner, Christopher C.; Newman, Rochelle S.; Dilley, Laura C.; Idsardi, William J.

    2015-01-01

    Purpose: A new literature has suggested that speech rate can influence the parsing of words quite strongly in speech. The purpose of this study was to investigate differences between younger adults and older adults in the use of context speech rate in word segmentation, given that older adults perceive timing information differently from younger…

  4. Bouts of responding: the relation between bout rate and the rate of variable-interval reinforcement.

    PubMed Central

    Shull, Richard L; Grimes, Julie A; Bennett, J Adam

    2004-01-01

    By nose poking a lighted key, rats obtained food pellets on either a variable-interval schedule of reinforcement or a schedule that required an average of four additional responses after the end of tile variable-interval component (a tandem variable-interval variable-ratio 4 schedule). With both schedule types, the mean variable interval was varied between blocks of sessions from 16 min to 0.25 min. Total rate of key poking increased similarly as a function of the reinforcer rate for the two schedule types, but response rate was higher with than without the four-response requirement. Analysis of log survivor plots of interresponse times showed that key poking occurred in bouts. The rate of initiating bouts increased as a function of reinforcer rate but was either unaffected or was decreased by adding the four-response requirement. Within-bout response rate was insensitive to reinforcer rate and only inconsistently affected by the four-response requirement. For both kinds of schedule, the ratio of bout time to between-bout pause time was approximately a power function of reinforcer rate, with exponents above and below 1.0. PMID:15113134

  5. Relational Responding Modulates and Reverses Affective Ratings in Evaluative Conditioning

    ERIC Educational Resources Information Center

    Molet, Mikael; Macquet, Benjamin; Charley, Gregory

    2013-01-01

    Three experiments explored relational responding in evaluative conditioning. In Experiment 1, the participants were trained with a computer task to make relational responses by putting CSs of different sizes in boxes in order of size. Subsequently they were instructed that these different sized CSs represented different intensities of hypothetical…

  6. Teacher-Education Graduate Surveys: Variables Related to Response Rate.

    ERIC Educational Resources Information Center

    Boser, Judith

    1988-01-01

    Data on survey methodology employed in follow-up surveys of graduates was collected, via questionnaire, from 226 teacher education programs. Response rates correlated significantly with number of attempts to reach graduates. Other variables included questionnaire length, postage provisions, use of incentives, response deadline, and personalization…

  7. Problems relating to the classical rate-gyro

    NASA Astrophysics Data System (ADS)

    Borello, L.

    1981-08-01

    A mathematical model is developed for evaluating the accuracy of classical rate-gyros. An analysis is presented of the influence of secondary input signals associated with the angular velocity components of the platform. Ways to minimize the effects of these secondary signals are examined.

  8. CREME96 and Related Error Rate Prediction Methods

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.

    2012-01-01

    Predicting the rate of occurrence of single event effects (SEEs) in space requires knowledge of the radiation environment and the response of electronic devices to that environment. Several analytical models have been developed over the past 36 years to predict SEE rates. The first error rate calculations were performed by Binder, Smith and Holman. Bradford and Pickel and Blandford, in their CRIER (Cosmic-Ray-Induced-Error-Rate) analysis code introduced the basic Rectangular ParallelePiped (RPP) method for error rate calculations. For the radiation environment at the part, both made use of the Cosmic Ray LET (Linear Energy Transfer) spectra calculated by Heinrich for various absorber Depths. A more detailed model for the space radiation environment within spacecraft was developed by Adams and co-workers. This model, together with a reformulation of the RPP method published by Pickel and Blandford, was used to create the CR ME (Cosmic Ray Effects on Micro-Electronics) code. About the same time Shapiro wrote the CRUP (Cosmic Ray Upset Program) based on the RPP method published by Bradford. It was the first code to specifically take into account charge collection from outside the depletion region due to deformation of the electric field caused by the incident cosmic ray. Other early rate prediction methods and codes include the Single Event Figure of Merit, NOVICE, the Space Radiation code and the effective flux method of Binder which is the basis of the SEFA (Scott Effective Flux Approximation) model. By the early 1990s it was becoming clear that CREME and the other early models needed Revision. This revision, CREME96, was completed and released as a WWW-based tool, one of the first of its kind. The revisions in CREME96 included improved environmental models and improved models for calculating single event effects. The need for a revision of CREME also stimulated the development of the CHIME (CRRES/SPACERAD Heavy Ion Model of the Environment) and MACREE (Modeling and

  9. Linking rates of diffusion and consumption in relation to resources.

    PubMed

    Avgar, Tal; Kuefler, Daniel; Fryxell, John M

    2011-08-01

    The functional response is a fundamental model of the relationship between consumer intake rate and resource abundance. The random walk is a fundamental model of animal movement and is well approximated by simple diffusion. Both models are central to our understanding of numerous ecological processes but are rarely linked in ecological theory. To derive a synthetic model, we draw on the common logical premise underlying these models and show how the diffusion and consumption rates of consumers depend on elementary attributes of naturally occurring consumer-resource interactions: the abundance, spatial aggregation, and traveling speed of resources as well as consumer handling time and directional persistence. We show that resource aggregation may lead to increased consumer diffusion and, in the case of mobile resources, reduced consumption rate. Resource-dependent movement patterns have traditionally been attributed to area-restricted search, reflecting adaptive decision making by the consumer. Our synthesis provides a simple alternative hypothesis that such patterns could also arise as a by-product of statistical movement mechanics. PMID:21750382

  10. Relating reconnection rate, exhaust structure and effective resistivity

    SciTech Connect

    Singh, Nagendra

    2014-03-15

    The magnetic reconnection structure consists of a central diffusion region (CDR) and a cone or wedge shaped reconnection exhaust containing accelerated plasma flows and electromagnetic fluctuations. We predict here the relationship among the exhaust half-cone angle (θ{sub e}), the half width (w) of the CDR, the outflow velocity V{sub o}, and the effective resistivity (η{sub eff}), which includes the effects of all the nonideal terms in the generalized Ohm's law. The effective resistivity is defined as the ratio of reconnection electric field E{sub rec} to the current density J{sub y} at the X point and it essentially represents the loss of momentum from the current-carrying plasma particles due to scattering by waves, their inertia or outflux from the CDR. The relation is checked against relevant results previously reported from laboratory experiments, space observations, and simulations, showing excellent agreement. The relation can be used for estimating the ad-hoc effective resistivity often used in magnetohydrodynamic modeling of reconnection.

  11. Supernova Rates, Rise-Times, and their Relations to Progenitors

    NASA Astrophysics Data System (ADS)

    Gonzalez Gaitan, Santiago

    Supernovae are fundamental in astronomy: they inject high mass elements into the interstellar medium enriching the chemistry of galaxies, they feed processes of star formation and active galactic nuclei, and they have been a key for the developments in cosmology of the past decades. This dissertation presents a set of subluminous type Ia supernovae (SNe Ia) at z > 0.1 from the Supernova Legacy Survey (SNLS). These faint and short-lived transients are found in massive and passive host galaxies. We measure a volumetric rate as a function of redshift that is different from the normal SN Ia population. The observations point towards a long delay time since the birth of the progenitors systems and argue for progenitor stars of initial low mass. We calculate a stretch-corrected rise-time since explosion to maximum brightness for different sets of SNe Ia. We find that a fiducial 17 day quadratic rise is sufficient to explain all SNe Ia, including subluminous ones, arguing for their homogeneity throughout the entire light-curve. Subluminous SNe Ia are powered by as little as 0.05 solar masses of radioactive nickel synthesized in the explosion. Theoretical models need to explain these challenging weak explosions within the framework of SNe Ia. Finally, we develop one of the first robust automated techniques to identify plateau supernovae (SNe IIP) in large photometric transient surveys. This simple method was tested with a variety of real and simulated SN samples and proved to be effective across different redshifts. Such a photometric typing will be of great power for coming surveys and will allow numerous scientific studies of SNe IIP.

  12. Comparison of the sputter rates of oxide films relative to the sputter rate of SiO{sub 2}

    SciTech Connect

    Baer, D. R.; Engelhard, M. H.; Lea, A. S.; Nachimuthu, P.; Droubay, T. C.; Kim, J.; Lee, B.; Mathews, C.; Opila, R. L.; Saraf, L. V.; Stickle, W. F.; Wallace, R. M.; Wright, B. S.

    2010-09-15

    There is a growing interest in knowing the sputter rates for a wide variety of oxides because of their increasing technological importance in many different applications. To support the needs of users of the Environmental Molecular Sciences Laboratory, a national scientific user facility, as well as our research programs, the authors made a series of measurements of the sputter rates from oxide films that have been grown by oxygen plasma-assisted molecular beam epitaxy, pulsed laser deposition, atomic layer deposition, electrochemical oxidation, or sputter deposition. The sputter rates for these oxide films were determined in comparison with those from thermally grown SiO{sub 2}, a common reference material for sputter rate determination. The film thicknesses and densities for most of these oxide films were measured using x-ray reflectivity. These oxide films were mounted in an x-ray photoelectron or Auger electron spectrometer for sputter rate measurements using argon ion sputtering. Although the primary objective of this work was to determine relative sputter rates at a fixed angle, the measurements also examined (i) the angle dependence of the relative sputter rates, (ii) the energy dependence of the relative sputter rates, and (iii) the extent of ion beam induced reduction for some oxides. Oxide films examined include SiO{sub 2}, Al{sub 2}O{sub 3}, CeO{sub 2}, Cr{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, HfO{sub 2}, In-Sn oxide, Ta{sub 2}O{sub 5}, TiO{sub 2} (anatase, rutile, and amorphous), and ZnO. The authors found that the sputter rates for the oxides can vary up to a factor of 2 (usually lower) from that observed for SiO{sub 2}. The ratios of sputter rates relative to those of SiO{sub 2} appear to be relatively independent of ion beam energy in the range of 1-4 kV and for incident angles <50 deg. As expected, the extent of ion beam induced reduction of the oxides varies with the sputter angle.

  13. Comparison of the Sputter Rates of Oxide Films Relative to the Sputter Rate of SiO2

    SciTech Connect

    Baer, Donald R.; Engelhard, Mark H.; Lea, Alan S.; Nachimuthu, Ponnusamy; Droubay, Timothy C.; Kim, J.; Lee, B.; Mathews, C.; Opila, R. L.; Saraf, Laxmikant V.; Stickle, William F.; Wallace, Robert; Wright, B. S.

    2010-09-02

    Because of the increasing technological importance of oxide films for a variety of applications, there is a growing interest in knowing the sputter rates for a wide variety of oxides. To support needs of users of the Environmental Molecular Sciences Laboratory (EMSL) User facility as well as our research programs, we have made a series of measurements of the sputter rates for oxide films that have been grown by oxygen plasma assisted molecular beam epitaxy (OPA-MBE), pulsed laser deposition (PLD), Atomic Layer Deposition (ALD), electrochemical oxidation, or sputter deposition. The sputter rates for these oxide films were determined in comparison to the sputter rates for thermally grown SiO2, a common sputter rate reference material. The film thicknesses and densities of these films were usually measured using x-ray reflectivity (XRR). These samples were mounted in an x-ray photoelectron spectroscopy (XPS) system or an Auger electron spectrometer for sputtering measurements using argon ion sputtering. Although the primary objective was to determine relative sputter rates at a fixed angle, the measurements were also used to determine: i) the angle dependence of the relative sputter rates; ii) the energy dependence of the relative sputter rates; and iii) the extent of ion beam reduction for the various oxides. Materials examined include: SiO2 (reference films), Al2O3, CeO2, Cr2O3, Fe2O3, HfO2, ITO (In-Sn-oxide) Ta2O5, TiO2 (anatase and rutile) and ZnO. We find that the sputter rates for the oxides can vary up to a factor of two (usually slower) from that observed for SiO2. The ratios of sputter rates to SiO2 appear to be relatively independent of ion beam energy for the range of 1kV to 4 kV and for incident angles of less than 50º. As expected, the ion beam reduction of the oxides varies with the sputter angle. These studies demonstrate that we can usually obtain sputter rate reproducibility better than 5% for similar oxide films.

  14. Protostellar spin-down: a planetary lift?

    NASA Astrophysics Data System (ADS)

    Bouvier, J.; Cébron, D.

    2015-11-01

    When they first appear in the HR diagram, young stars rotate at a mere 10 per cent of their break-up velocity. They must have lost most of the angular momentum initially contained in the parental cloud, the so-called angular momentum problem. We investigate here a new mechanism by which large amounts of angular momentum might be shed from young stellar systems, thus yielding slowly rotating young stars. Assuming that planets promptly form in circumstellar discs and rapidly migrate close to the central star, we investigate how the tidal and magnetic interactions between the protostar, its close-in planet(s), and the inner circumstellar disc can efficiently remove angular momentum from the central object. We find that neither the tidal torque nor the variety of magnetic torques acting between the star and the embedded planet are able to counteract the spin-up torques due to accretion and contraction. Indeed, the former are orders of magnitude weaker than the latter beyond the corotation radius and are thus unable to prevent the young star from spinning up. We conclude that star-planet interaction in the early phases of stellar evolution does not appear as a viable alternative to magnetic star-disc coupling to understand the origin of the low angular momentum content of young stars.

  15. The Relations and Comparisons between Reading Comprehension and Reading Rate of Japanese High School EFL Learners

    ERIC Educational Resources Information Center

    Fujita, Ken; Yamashita, Junko

    2014-01-01

    The current study investigated the relation and comparison of reading comprehension and reading rate in Japanese high school EFL learners. One hundred and forty-eight tenth-graders in a Japanese high school participated in this study. Results showed that the relation between reading comprehension and reading rate was weak, but significant (r =…

  16. 13 CFR 120.1060 - Confidentiality of Reports, Risk Ratings and related Confidential Information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Confidentiality of Reports, Risk Ratings and related Confidential Information. 120.1060 Section 120.1060 Business Credit and Assistance... section. The Report, Risk Rating, and Confidential Information must not be relied upon for any...

  17. 13 CFR 120.1060 - Confidentiality of Reports, Risk Ratings and related Confidential Information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Confidentiality of Reports, Risk Ratings and related Confidential Information. 120.1060 Section 120.1060 Business Credit and Assistance... section. The Report, Risk Rating, and Confidential Information must not be relied upon for any...

  18. 13 CFR 120.1060 - Confidentiality of Reports, Risk Ratings and related Confidential Information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Confidentiality of Reports, Risk Ratings and related Confidential Information. 120.1060 Section 120.1060 Business Credit and Assistance... section. The Report, Risk Rating, and Confidential Information must not be relied upon for any...

  19. 13 CFR 120.1060 - Confidentiality of Reports, Risk Ratings and related Confidential Information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Confidentiality of Reports, Risk Ratings and related Confidential Information. 120.1060 Section 120.1060 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Risk-Based Lender Oversight Supervision § 120.1060 Confidentiality of Reports, Risk Ratings and...

  20. Similar relative mutation rates in the three genetic compartments of Mesostigma and Chlamydomonas.

    PubMed

    Hua, Jimeng; Smith, David Roy; Borza, Tudor; Lee, Robert W

    2012-01-01

    Levels of nucleotide substitution at silent sites in organelle versus nuclear DNAs have been used to estimate relative mutation rates among these compartments and explain lineage-specific features of genome evolution. Synonymous substitution divergence values in animals suggest that the rate of mutation in the mitochondrial DNA is 10-50 times higher than that of the nuclear DNA, whereas overall data for most seed plants support relative mutation rates in mitochondrial, plastid, and nuclear DNAs of 1:3:10. Little is known about relative mutation rates in green algae, as substitution rate data is limited to only the mitochondrial and nuclear genomes of the chlorophyte Chlamydomonas. Here, we measure silent-site substitution rates in the plastid DNA of Chlamydomonas and the three genetic compartments of the streptophyte green alga Mesostigma. In contrast to the situation in animals and land plants, our results support similar relative mutation rates among the three genetic compartments of both Chlamydomonas and Mesostigma. These data are discussed in relation to published intra-species genetic diversity data for the three genetic compartments of Chlamydomonas and are ultimately used to address contemporary hypotheses on the organelle genome evolution. To guide future work, we describe evolutionary divergence data of all publically available Mesostigma viride strains and identify, for the first time, three distinct lineages of Mesostigma. PMID:21621456

  1. Dispersion relation and growth rate in a Cherenkov free electron laser: Finite axial magnetic field

    SciTech Connect

    Kheiri, Golshad; Esmaeilzadeh, Mahdi

    2013-12-15

    A theoretical analysis is presented for dispersion relation and growth rate in a Cherenkov free electron laser with finite axial magnetic field. It is shown that the growth rate and the resonance frequency of Cherenkov free electron laser increase with increasing axial magnetic field for low axial magnetic fields, while for high axial magnetic fields, they go to a saturation value. The growth rate and resonance frequency saturation values are exactly the same as those for infinite axial magnetic field approximation. The effects of electron beam self-fields on growth rate are investigated, and it is shown that the growth rate decreases in the presence of self-fields. It is found that there is an optimum value for electron beam density and Lorentz relativistic factor at which the maximum growth rate can take place. Also, the effects of velocity spread of electron beam are studied and it is found that the growth rate decreases due to the electron velocity spread.

  2. A cloud model-radiative model combination for determining microwave TB-rain rate relations

    NASA Technical Reports Server (NTRS)

    Szejwach, Gerard; Adler, Robert F.; Jobard, Esabelle; Mack, Robert A.

    1986-01-01

    The development of a cloud model-radiative transfer model combination for computing average brightness temperature, T(B), is discussed. The cloud model and radiative transfer model used in this study are described. The relations between rain rate, cloud and rain water, cloud and precipitation ice, and upwelling radiance are investigated. The effects of the rain rate relations on T(B) under different climatological conditions are examined. The model-derived T(B) results are compared to the 92 and 183 GHz aircraft observations of Hakkarinen and Adler (1984, 1986) and the radar-estimated rain rate of Hakkarinen and Adler (1986); good correlation between the data is detected.

  3. The pattern of mammalian evolution and the relative rate of molecular evolution

    SciTech Connect

    Easteal, S. )

    1990-01-01

    The rates of nucleotide substitution at four genes in four orders of eutherian mammals are compared in relative rate tests using marsupial orthologs for reference. There is no evidence of systematic variation in evolutionary rate among the orders. The sequences are used to reconstruct the phylogeny of the orders using maximum likelihood, parsimony and compatibility methods. A branching order of rodent then ungulate then primate and lagomorph is overwhelmingly indicated. The nodes of the nucleotide based cladograms are widely separated in relation to the total lengths of the branches. The assumption of a star phylogeny that underlies Kimura's test for molecular evolutionary rate variation is shown to be invalid for eutherian mammals. Excess variance in nucleotide or amino acid differences between mammalian orders, above that predicted by neutral theory is explained better by variation in divergence time than by variation in evolutionary rate.

  4. Age-related changes in auditory and visual interactions in temporal rate perception

    PubMed Central

    Brooks, Cassandra J.; Anderson, Andrew J.; Roach, Neil W.; McGraw, Paul V.; McKendrick, Allison M.

    2015-01-01

    We investigated how aging affects the integration of temporal rate for auditory flutter (amplitude modulation) presented with visual flicker. Since older adults were poorer at detecting auditory amplitude modulation, modulation depth was individually adjusted so that temporal rate was equally discriminable for 10 Hz flutter and flicker, thereby balancing the reliability of rate information available to each sensory modality. With age-related sensory differences normalized in this way, rate asynchrony skewed both auditory and visual rate judgments to the same extent in younger and older adults. Therefore, reliability-based weighting of temporal rate is preserved in older adults. Concurrent presentation of synchronous 10 Hz flicker and flutter improved temporal rate discrimination consistent with statistically optimal integration in younger but not older adults. In a control experiment, younger adults were presented with the same physical auditory stimulus as older adults. This time, rate asynchrony skewed perceived rate with greater auditory weighting rather than balanced integration. Taken together, our results indicate that integration of discrepant auditory and visual rates is not altered due to the healthy aging process once sensory deficits are accounted for, but that aging does abolish the minor improvement in discrimination performance seen in younger observers when concordant rates are integrated. PMID:26624937

  5. Existing and Past Methods of Test and Rating Standards Related to Integrated Heat Pump Technologies

    SciTech Connect

    Reedy, Wayne R.

    2010-07-01

    This report evaluates existing and past US methods of test and rating standards related to electrically operated air, water, and ground source air conditioners and heat pumps, 65,000 Btu/hr and under in capacity, that potentiality incorporate a potable water heating function. Two AHRI (formerly ARI) standards and three DOE waivers were identified as directly related. Six other AHRI standards related to the test and rating of base units were identified as of interest, as they would form the basis of any new comprehensive test procedure. Numerous other AHRI and ASHRAE component test standards were also identified as perhaps being of help in developing a comprehensive test procedure.

  6. Mental workload measurement: Event-related potentials and ratings of workload and fatigue

    NASA Technical Reports Server (NTRS)

    Biferno, M. A.

    1985-01-01

    Event-related potentials were elicited when a digitized word representing a pilot's call-sign was presented. This auditory probe was presented during 27 workload conditions in a 3x3x3 design where the following variables were manipulated: short-term load, tracking task difficulty, and time-on-task. Ratings of workload and fatigue were obtained between each trial of a 2.5-hour test. The data of each subject were analyzed individually to determine whether significant correlations existed between subjective ratings and ERP component measures. Results indicated that a significant number of subjects had positive correlations between: (1) ratings of workload and P300 amplitude, (2) ratings of workload and N400 amplitude, and (3) ratings of fatigue and P300 amplitude. These data are the first to show correlations between ratings of workload or fatigue and ERP components thereby reinforcing their validity as measures of mental workload and fatigue.

  7. Thunderstorm cloud height-rainfall rate relations for use with satellite rainfall estimation techniques

    NASA Technical Reports Server (NTRS)

    Adler, R. F.; Mack, R. A.

    1984-01-01

    Observational studies of thunderstorm cloud height-rainfall rate and cloud height-volume rainfall rate relations are reviewed with significant variations being noted among climatological regimes. Analysis of the Florida (summer) and Oklahoma (spring) relations are made using a one-dimensional cloud model to ascertain the important factors in determining the individual cloud-rain relations and the differences between the two regimes. In general, the observed relations are well simulated by the model-based calculations. The generally lower predicted rain rates in Oklahoma (as compared to Florida) result from lower precipitation efficiencies which are due to a combination of larger entrainment (related to larger vertical wind shear) and drier environment. The generally steeper slope of the Oklahoma rain rate height curves is shown to be due to a stronger variation in maximum vertical velocity with cloud top height, which, in turn, is related to the greater static stability in the range of cloud tops. The impact of the regime-to-regime variations on empirical rain estimation schemes based on satellite-observed cloud height or cloud temperature information is discussed and a rain estimation approach based on model-generated cloud-rain relations is outlined.

  8. Relative rates for plasma homo- and copolymerizations of olefins in a homologous series of fluorinated ethylenes

    NASA Technical Reports Server (NTRS)

    Golub, M. A.; Wydeven, T.

    1997-01-01

    It is well known that the rate of plasma polymerization, or deposition rate, of a given monomer depends on various plasma process parameters, e.g., monomer flow rate, pressure, power, frequency (DC, rf or microwave), location of the substrate in the reactor, reactor geometry or configuration, and temperature. In contrast, little work has been done to relate deposition rates to monomer structures for a homologous series of monomers where the rates are obtained under identical plasma process parameters. For the particular series of fluorinated ethylenes (C2HxF4-x; x = 0-4), deposition rates were reported for ethylene (ET), vinyl fluoride, vinylidene fluoride and tetrafluoroethylene (TFE), but for plasma polymerizations carried out under different discharge conditions, e.g., pressure, current density, and electrode temperature. Apparently, relative deposition rates were reported for only two members of that series (ET, x = 4, and TFE, x = 0) for which the plasma polymerizations were conducted under identical conditions. We now present relative deposition rates for both homopolymerizations and copolymerizations of the entire series of fluorinated ethylenes (x = 0-4). Our interest in such rates stems from prior work on the plasma copolymerization of ET and TFE in which it was found that the deposition rates for the plasma copolymers, when plotted versus mol % TFE in the ET/TFE feed stock, followed a concave-downward curve situated above the straight line joining the deposition rates for the plasma homopolymers. This type of plot (observed also for an argon-ET/TFE plasma copolymerization) indicated a positive interaction between ET and TFE such that each monomer apparently "sensitized" the plasma copolymerization of the other. Since the shape of that plot is not altered if mol % TFE is replaced by F/C, the fluorine-to-carbon ratio, this paper aims (1) to show how the relative deposition rates for plasma copolymers drawn from all pairs of monomers in the C2HxF4-x series

  9. Abnormalities in Automatic Processing of Illness-Related Stimuli in Self-Rated Alexithymia

    PubMed Central

    Brandt, Laura; Pintzinger, Nina M.; Tran, Ulrich S.

    2015-01-01

    Aim To investigate abnormalities in automatic information processing related to self- and observer-rated alexithymia, especially with regard to somatization, controlling for confounding variables such as depression and affect. Sample 89 healthy subjects (60% female), aged 19–71 years (M = 32.1). 58 subjects were additionally rated by an observer. Measures Alexithymia (self-rating: TAS-20, observer rating: OAS); automatic information processing (priming task including verbal [illness-related, negative, positive, neutral] and facial [negative, positive, neutral] stimuli); somatoform symptoms (SOMS-7T); confounders: depression (BDI), affect (PANAS). Results Higher self-reported alexithymia scores were associated with lower reaction times for negative (r = .19, p < .10) and positive (r = .26, p < .05) verbal primes when the target was illness-related. Self-reported alexithymia was correlated with number (r = .42, p < .01) and intensity of current somatoform symptoms (r = .36, p < .01), but unrelated to observer-rated alexithymia (r = .11, p = .42). Discussion Results indicate a faster allocation of attentional resources away from task-irrelevant information towards illness-related stimuli in alexithymia. Considering the close relationship between alexithymia and somatization, these findings are compatible with the theoretical view that alexithymics focus strongly on bodily sensations of emotional arousal. A single observer rating (OAS) does not seem to be an adequate alexithymia-measure in community samples. PMID:26090893

  10. Relative rates of evolution in the coding and control regions of African mtDNAs.

    PubMed

    Howell, Neil; Elson, Joanna L; Howell, Corinna; Turnbull, Douglass M

    2007-10-01

    Reduced median networks of African haplogroup L mitochondrial DNA (mtDNA) sequences were analyzed to determine the pattern of substitutions in both the noncoding control and coding regions. In particular, we attempted to determine the causes of the previously reported (Howell et al. 2004) violation of the molecular clock during the evolution of these sequences. In the coding region, there was a significantly higher rate of substitution at synonymous sites than at nonsynonymous sites as well as in the tRNA and rRNA genes. This is further evidence for the operation of purifying selection during human mtDNA evolution. For most sites in the control region, the relative rate of substitution was similar to the rate of neutral evolution (assumed to be most closely approximated by the substitution rate at 4-fold degenerate sites). However, there are a number of mutational hot spots in the control region, approximately 3% of the total sites, that have a rate of substitution greater than the neutral rate, at some sites by more than an order of magnitude. It is possible either that these sites are evolving under conditions of positive selection or that the substitution rate at some sites in the control region is strongly dependent upon sequence context. Finally, we obtained preliminary evidence for "nonideal" evolution in the control region, including haplogroup-specific substitution patterns and a decoupling between relative rates of substitution in the control and coding regions. PMID:17642471

  11. Gender- and age-related differences in heart rate dynamics: are women more complex than men?

    NASA Technical Reports Server (NTRS)

    Ryan, S. M.; Goldberger, A. L.; Pincus, S. M.; Mietus, J.; Lipsitz, L. A.

    1994-01-01

    OBJECTIVES. This study aimed to quantify the complex dynamics of beat-to-beat sinus rhythm heart rate fluctuations and to determine their differences as a function of gender and age. BACKGROUND. Recently, measures of heart rate variability and the nonlinear "complexity" of heart rate dynamics have been used as indicators of cardiovascular health. Because women have lower cardiovascular risk and greater longevity than men, we postulated that there are important gender-related differences in beat-to-beat heart rate dynamics. METHODS. We analyzed heart rate dynamics during 8-min segments of continuous electrocardiographic recording in healthy young (20 to 39 years old), middle-aged (40 to 64 years old) and elderly (65 to 90 years old) men (n = 40) and women (n = 27) while they performed spontaneous and metronomic (15 breaths/min) breathing. Relatively high (0.15 to 0.40 Hz) and low (0.01 to 0.15 Hz) frequency components of heart rate variability were computed using spectral analysis. The overall "complexity" of each heart rate time series was quantified by its approximate entropy, a measure of regularity derived from nonlinear dynamics ("chaos" theory). RESULTS. Mean heart rate did not differ between the age groups or genders. High frequency heart rate power and the high/low frequency power ratio decreased with age in both men and women (p < 0.05). The high/low frequency power ratio during spontaneous and metronomic breathing was greater in women than men (p < 0.05). Heart rate approximate entropy decreased with age and was higher in women than men (p < 0.05). CONCLUSIONS. High frequency heart rate spectral power (associated with parasympathetic activity) and the overall complexity of heart rate dynamics are higher in women than men. These complementary findings indicate the need to account for gender-as well as age-related differences in heart rate dynamics. Whether these gender differences are related to lower cardiovascular disease risk and greater longevity in

  12. Reconstruction of high frame rate image sequences in biomechanical related areas.

    PubMed

    Costa, Monica; Soares, Salviano; Barroso, Joao

    2010-01-01

    Regular video cameras shoot normally at 25/30 frames per second (fps). Actually there are available in the market equipments that allow us to acquire video at 1.000.000 fps. When we observe a video sequence it becomes noticeable that great part of the information remains unchanged regardless of the bit rate or frame rate used. One origin of discontinuity in video signals is directly related to movement. Several areas use high frame rate images to analyze and comprehend certain events or effects, biomechanical engineering is one of them. Biomechanics engineering studies the mechanics of a living body, especially the forces exerted by muscles and gravity on the skeletal structure. Some examples are athlete assessment, were images are capture and then the acquired parameters are analyzed. This article describes a new methodology to decrease the space needed to store high frame rate image sequences in the specific case of biomechanical related areas. PMID:21095875

  13. Relative rate constants for the reactions of OH with methane and methyl chloroform

    NASA Technical Reports Server (NTRS)

    Demore, W. B.

    1992-01-01

    Atmospheric lifetimes of methane and methyl chloroform are largely determined by the rates of their reactions with hydroxyl radical. The relative lifetimes for this loss path are inversely proportional to the ratio of the corresponding rate coefficients. The relative rate constants were measured in a slow-flow, temperature-controlled photochemical reactor, and were based on rates of disappearance of the parent compounds as measured by FTIR spectroscopy. The temperature range was 277-356 K. Hydroxyl radicals were generated by 254 nm photolysis of O3 in the presence of water vapor. The preferred Arrhenius expression for the results is k(CH3CCl3)/k(CH4) = 0.62 exp (291/T), corresponding to a value of 1.65 at 298 K and 1.77 at 277 K. The respective uncertainties are 5 and 7 percent.

  14. Are gingival and periodontal conditions related to salivary gland flow rates in healthy individuals?

    PubMed

    Crow, H C; Ship, J A

    1995-11-01

    Some have suggested that gingival and periodontal health is related to salivary gland function; however, there are few data to support this hypothesis. The purpose of this study was to determine if correlations existed between major salivary gland flow rates and gingival and periodontal conditions in people of different ages. The results suggest that there is no consistent relationship between major salivary gland flow rates and gingival and periodontal conditions in healthy people. PMID:7499648

  15. The solar cycle variation of the rates of CMEs and related activity

    NASA Technical Reports Server (NTRS)

    Webb, David F.

    1991-01-01

    Coronal mass ejections (CMEs) are an important aspect of the physics of the corona and heliosphere. This paper presents results of a study of occurrence frequencies of CMEs and related activity tracers over more than a complete solar activity cycle. To properly estimate occurrence rates, observed CME rates must be corrected for instrument duty cycles, detection efficiencies away from the skyplane, mass detection thresholds, and geometrical considerations. These corrections are evaluated using CME data from 1976-1989 obtained with the Skylab, SMM and SOLWIND coronagraphs and the Helios-2 photometers. The major results are: (1) the occurrence rate of CMEs tends to track the activity cycle in both amplitude and phase; (2) the corrected rates from different instruments are reasonably consistent; and (3) over the long term, no one class of solar activity tracer is better correlated with CME rate than any other (with the possible exception of type II bursts).

  16. Are smoking and passive smoking related with heart rate variability in male adolescents?

    PubMed Central

    Gondim, Renata Melo; Farah, Breno Quintella; Santos, Carolina da Franca Bandeira Ferreira; Ritti-Dias, Raphael Mendes

    2015-01-01

    Objective To analyze the relation between smoking and passive smoking with heart rate variability parameters in male adolescents. Methods The sample consisted of 1,152 males, aged 14 and 19 years. Data related to smoking and passive smoking were collected using a questionnaire. RR intervals were obtained by a heart rate monitor, on supine position, for 10 minutes. After collecting the RR intervals, time (standard deviation of all RR intervals, root mean square of the squared differences between adjacent normal RR intervals and the percentage of adjacent intervals over 50ms) and frequency domains (low and high frequency and sympathovagal balance) parameters of heart rate variability were obtained. Results No significant differences between smoker and nonsmoker adolescents were observed in heart rate variability parameters (p>0.05). Similarly, heart rate variability parameters did not show significant difference between exposed and not exposed to passive smoking (p>0.05). Conclusion Cigarette smoking and passive smoking are not related to heart rate variability in adolescence. PMID:25993065

  17. Relative Rates for Plasma Homo- and Copolymerizations of Olefins in a Homologous Series of Fluorinated Ethylenes

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Wydeven, Theodore; Kliss, Mark (Technical Monitor)

    1996-01-01

    The relative rates of plasma (co)polymerizations of ethylene, vinyl fluoride, vinylidene fluoride, trifluoroethylene and tetrafluoroethylene (VF(sub x); x = 0-4, respectively) were determined in an rf, capacitively coupled, tubular reactor with external electrodes using identical plasma parameters. The averages of deposition rates obtained by both microgravimetry and ellipsometry were plotted versus the F/C ratios of the monomers or monomer blends. The deposition rates for VF(sub x)(x = 1-3) and 20 monomer blends were all located above a straight line joining the rates for VF(sub 0) and VF(sub 4), following a concave-downward plot of deposition rate versus F/C ratio similar to that reported previously for VF(sub 0)/VF(sub 4) blends. The deposition rates for VF(sub m)/VF(sub n) blends (m = 3 or 4; n = 0-2) were all greater than expected for non-interacting monomers; those for VF(sub 0)/VF(sub 2) and VF(sub 1)/VF(sub 2) blends were all lower than expected; while those for VF(sub 0)/VF(sub 1) and VF(sub 3)/VF(sub 4) blends fen on a straightline plot versus F/C ratio, indicative of apparent non-interaction between monomers. The mechanisms for plasma (co)polymerizations of VF(sub x) monomers responsible for the wide range of relative deposition rates remain to be elucidated.

  18. New test of general relativity - Measurement of de Sitter geodetic precession rate for lunar perigee

    NASA Technical Reports Server (NTRS)

    Bertotti, Bruno; Ciufolini, Ignazio; Bender, Peter L.

    1987-01-01

    According to general relativity, the calculated rate of motion of lunar perigee should include a contribution of 19.2 msec/yr from geodetic precession. It is shown that existing analyses of lunar-laser-ranging data confirm the general-relativistic rate for geodetic precession with respect to the planetary dynamical frame. In addition, the comparison of earth-rotation results from lunar laser ranging and from VLBI shows that the relative drift of the planetary dynamical frame and the extragalactic VLBI reference frame is small. The estimated accuracy is about 10 percent.

  19. Plasticity in relative growth rate after a reduction in nitrogen availability is related to root morphological and physiological responses

    PubMed Central

    Useche, Antonio; Shipley, Bill

    2010-01-01

    Background and Aims To maximize growth and fitness a plant must adjust its phenotype by an amount and speed that matches changes in nitrogen availability. To determine how plastic ontogenetic changes in root physiological and morphological traits interact and whether or not these responses are likely to maximize growth, ontogenetic changes in relative growth rate (RGR, proportional rate of change of plant dry mass), unit root rate (URR, rate of change of plant dry mass per unit root length or area), specific root length (SRL, root length per dry root mass), specific root area (SRA, root area per dry root mass), and other root traits before and after a decrease in nitrogen supply, were studied in ten herbaceous species. Methods Plants of each species were grown in hydroponic culture under controlled conditions in a control treatment where the supply of nitrogen remained constant at 1 mm, and in a stress treatment where the nitrogen supply was abruptly reduced from 1 to 0·01 mm during the growth period. Key Results and Conclusions In the treatment series the number of bifurcations per root area and per root length, specific root area (SRA) and length (SRL), areal (URRarea) and length-based (URRmass) unit root rate and RGR decreased, and root tissue density increased relative to the control. Species having greater plasticity in the percentage decrease in SRA at the end of the experiment also had smaller reductions in RGR; plasticity in SRA is therefore adaptive. In contrast, species which showed a greater reduction in URRarea and in the number of bifurcations per root area and per root length, showed stronger reductions in RGR; plasticity in URRarea and in the number of bifurcations per root area and per root length is therefore not adaptive. The plastic responses observed in SRA, SRL and in root tissue density constitute a set of plastic adjustments that would lead to resource conservation in response nutrient stress. PMID:20639301

  20. End of the Spectacular Decrease in Fall-Related Mortality Rate: Men Are Catching Up

    PubMed Central

    Hartholt, Klaas A.; Polinder, Suzanne; van Beeck, Ed F.; van der Velde, Nathalie; van Lieshout, Esther M. M.; Patka, Peter

    2012-01-01

    Objectives. We determined time trends in numbers and rates of fall-related mortality in an aging population, for men and women. Methods. We performed secular trend analysis of fall-related deaths in the older Dutch population (persons aged 65 years or older) from 1969 to 2008, using the national Official-Cause-of-Death-Statistics. Results. Between 1969 and 2008, the age-adjusted fall-related mortality rate decreased from 202.1 to 66.7 per 100 000 older persons (decrease of 67%). However, the annual percentage change (change per year) in mortality rates was not constant, and could be divided into 3 phases: (1) a rapid decrease until the mid-1980s (men −4.1%; 95% confidence interval [CI] = −4.9, −3.2; women −6.5%; 95% CI, −7.1, −5.9), (2) flattening of the decrease until the mid-1990s (men −1.4%; 95% CI = −2.4, −0.4; women −2.0%; 95% CI = −3.4, −0.6), and (3) stable mortality rates for women (0.0%; 95% CI = −1.2, 1.3) and rising rates for men (1.9%; 95% CI = 0.6, 3.2) over the last decade. Conclusions. The spectacular decrease in fall-related mortality ended in the mid-1990s and is currently increasing in older men at similar rates to those seen in women. Because of the aging society, absolute numbers in fall-related deaths are increasing rapidly. PMID:22401528

  1. Age influences the relation between subjective valence ratings and emotional word use during autobiographical memory retrieval.

    PubMed

    Ford, Jaclyn H; DiGirolamo, Marissa A; Kensinger, Elizabeth A

    2016-09-01

    Recent research reveals an age-related increase in positive autobiographical memory retrieval using a number of positivity measures, including valence ratings and positive word use. It is currently unclear whether the positivity shift in each of these measures co-occurs, or if age uniquely influences multiple components of autobiographical memory retrieval. The current study examined the correspondence between valence ratings and emotional word use in young and older adults' autobiographical memories. Positive word use in narratives was associated with valence ratings only in young adults' narratives. Older adults' narratives contained a consistent level of positive word use regardless of valence rating, suggesting that positive words and concepts may be chronically accessible to older adults during memory retrieval, regardless of subjective valence. Although a relation between negative word use in narratives and negative valence ratings was apparent in both young and older adults, it was stronger in older adults' narratives. These findings confirm that older adults do vary their word use in accordance with subjective valence, but they do so in a way that is different from young adults. The results also point to a potential dissociation between age-related changes in subjective valence and in positive word use. PMID:26274398

  2. The Effect of Changes in Relative Humidity on the Hydration Rate of Pachuca Obsidian

    SciTech Connect

    Anovitz, Lawrence {Larry} M; Riciputi, Lee R; Cole, David R; Gruszkiewicz, Miroslaw {Mirek} S; Elam, J. Michael

    2006-01-01

    The effect of relative humidity on the hydration rate of obsidian and other glasses has been debated since the early work of (I. Friedman, R. Smith, Am. Antiquity 25 (1960) 476). While more recent work has been in general agreement that a relative humidity dependence does exist, hydration profiles as a function of relative humidity have not been obtained. In this paper we present the results of a study in which samples of Pachuca obsidian were hydrated for approximately 5 days at 150 C at relative humidities ranging from 21% to 100%, and the resultant profiles were measured by secondary ion mass spectrometry (SIMS). The results suggest that the hydration rate is, indeed, a function of relative humidity, but for the relative humidity levels commonly observed in most soils the effects on hydration dating are expected to be relatively small. In addition, analysis of the surface values as sorption isotherms and comparisons with nitrogen sorption isotherms suggests that water is relatively strongly bound to the obsidian surface. By assuming a situation in which the 'surface' refers to active centers within the glass we have shown that an adsorption model provides a useful approach to modeling the diffusive process.

  3. Decrease in rate of multiple sclerosis-related hospitalizations in Portugal

    PubMed Central

    Pereira, Marta; Lambrelli, Dimitra; Ramagopalan, Sreeram V.

    2016-01-01

    We sought to investigate the rate of multiple sclerosis (MS)-related hospitalizations in Portugal and assess whether there have been temporal changes as described in other countries. Using data from the Portuguese National Discharge Registry, we observed that between 2008 and 2013 the rate of MS-related hospitalizations decreased by 44%, from 15.9/100 person-years (95% confidence interval (CI: 14.9-16.9) in 2008 to 8.9/100 person-years (95% CI: 8.2-9.6) in 2013. The change in hospitalization rates is in accordance with what has been observed in other countries, and coincides with the release of new therapies for MS in Portugal.

  4. Citation Rate of Highly-Cited Papers in 100 Kinesiology-Related Journals

    ERIC Educational Resources Information Center

    Knudson, Duane

    2015-01-01

    This study extended previous research on several citation-based bibliometric variables for highly cited articles in a large (N = 100) number of journals related to Kinesiology. Total citations and citation rate of the 30 most highly cited articles in each journal were identified by searchers of "Google Scholar (GS)". Other major…

  5. Alcohol-Related Vehicular Death Rates for College Students in the Commonwealth of Virginia

    ERIC Educational Resources Information Center

    Turner, James; Bauerle, Jennifer; Keller, Adrienne

    2011-01-01

    Objective: Determine rate of college student alcohol-related vehicular traffic fatalities in Virginia during 2007. Participants: Undergraduates at colleges and universities in Virginia. Methods: Institutions with membership in the American College Health Association were invited to participate in a survey. Data collected from institutional reports…

  6. A BASIS FOR RELATIVE GROWTH RATE DIFFERENCES BETWEEN NATIVE AND INVASIVE FORBS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ABSTRACT The ability of invasives species to achieve higher relative growth rate (RGR) than their native counterparts has been widely documented. Little is known, however, about the underlying mechanisms driving RGR differences between native and invasive species. The objective of this study was t...

  7. Is the Physical Availability of Alcohol and Illicit Drugs Related to Neighborhood Rates of Child Maltreatment?

    ERIC Educational Resources Information Center

    Freisthler, Bridget; Needell, Barbara; Gruenewald, Paul J.

    2005-01-01

    Objective: This study examines how the availability of alcohol and illicit drugs (as measured by alcohol outlet density and police incidents of drug sales and possessions) is related to neighborhood rates of child abuse and neglect, controlling for other neighborhood demographic characteristics. Method: Data from substantiated reports of child…

  8. Response-Time Variability Is Related to Parent Ratings of Inattention, Hyperactivity, and Executive Function

    ERIC Educational Resources Information Center

    Gomez-Guerrero, Lorena; Martin, Cristina Dominguez; Mairena, Maria Angeles; Di Martino, Adriana; Wang, Jing; Mendelsohn, Alan L.; Dreyer, Benard P.; Isquith, Peter K.; Gioia, Gerard; Petkova, Eva; Castellanos, F. Xavier

    2011-01-01

    Objective: Individuals with ADHD are often characterized as inconsistent across many contexts. ADHD is also associated with deficits in executive function. We examined the relationships between response time (RT) variability on five brief computer tasks to parents' ratings of ADHD-related features and executive function in a group of children with…

  9. Community Colleges and Labor Market Conditions: How Does Enrollment Demand Change Relative to Local Unemployment Rates?

    ERIC Educational Resources Information Center

    Hillman, Nicholas W.; Orians, Erica Lee

    2013-01-01

    This study uses fixed-effects panel data techniques to estimate the elasticity of community college enrollment demand relative to local unemployment rates. The findings suggest that community college enrollment demand is counter-cyclical to changes in the labor market, as enrollments rise during periods of weak economic conditions. Using national…

  10. Absolute and Relative Reliability of Percentage of Syllables Stuttered and Severity Rating Scales

    ERIC Educational Resources Information Center

    Karimi, Hamid; O'Brian, Sue; Onslow, Mark; Jones, Mark

    2014-01-01

    Purpose: Percentage of syllables stuttered (%SS) and severity rating (SR) scales are measures in common use to quantify stuttering severity and its changes during basic and clinical research conditions. However, their reliability has not been assessed with indices measuring both relative and absolute reliability. This study was designed to provide…

  11. Understanding and Producing the Reduced Relative Construction: Evidence from Ratings, Editing and Corpora

    ERIC Educational Resources Information Center

    Hare, Mary; Tanenhaus, Michael K.; McRae, Ken

    2007-01-01

    Two rating studies demonstrate that English speakers willingly produce reduced relatives with internal cause verbs (e.g., "Whisky fermented in oak barrels can have a woody taste"), and judge their acceptability based on factors known to influence ambiguity resolution, rather than on the internal/external cause distinction. Regression analyses…

  12. The Acquisition of Vector Knowledge and Its Relation to Self-Rated Direction Sense

    ERIC Educational Resources Information Center

    Muehl, Karen A.; Sholl, M. Jeanne

    2004-01-01

    Self-rated sense of direction is reliably related to people's accuracy when pointing in the direction of unseen landmarks from imagined or actual perspectives. It is proposed that the cognitive substrate of accurate pointing responses is a vector representation, which is defined as an integrated network of displacement vectors. Experiment 1…

  13. The Influence of Selected Academic, Demographic, and Instructional Program Related Factors on Elementary Student Retention Rates

    ERIC Educational Resources Information Center

    Scott, Marshall, III

    2011-01-01

    The purpose of this study was to examine the influence of selected academic, demographic, and instructional program related factors on the retention rates of elementary school students. More specifically, this study was concerned with the relationship and predictability of the reading and mathematics variables scores, gender, ethnicity, program…

  14. The Impact of Implementation of Bundle to Reduce Catheter-Related Bloodstream Infection Rates

    PubMed Central

    Menegueti, Mayra Goncalves; Ardison, Kym Marcel Martins; Bellissimo-Rodrigues, Fernando; Gaspar, Gilberto Gambero; Martins-Filho, Olindo Assis; Puga, Marcelo Lourencini; Laus, Ana Maria; Basile-Filho, Anibal; Auxiliadora-Martins, Maria

    2015-01-01

    Background The aim of the study was to investigate how control bundles reduce the rate of central venous catheter-associated bloodstream infections (CVC-BSIs) rates in critically ill patients. Methods This is a prospective before-and-after study designed to evaluate whether a set of control measures (bundle) can help prevent CVC-BSI. The bundles included a checklist that aimed to correct practices related to CVC insertion, manipulation, and maintenance based on guidelines of the Center for Disease Control and Prevention (CDC). Results We examined 123 checklists before and 155 checklists after implementation of the training program. Compared with the pre-intervention period, CVC-BSI rates decreased. Hand hygiene techniques were used correctly. CVC-BSI incidence was 9.3 and 5.1 per 1,000 catheter-days before and after the training program, respectively. Conclusions The implementation of a bundle and training program effectively reduces CVC-BSI rates. PMID:26491498

  15. Relation between night visit rates and deprivation measures in one general practice.

    PubMed Central

    Carlisle, R D; Johnstone, S P; Pearson, J C

    1993-01-01

    OBJECTIVE--To compare night visit rates in different electoral wards of one general practice with the Jarman and Townsend deprivation scores and unemployment rates. DESIGN--Analysis of computerised workload data. SETTING--General practice in centre of Mansfield, Nottinghamshire. OUTCOME MEASURE--Visits made in 588 nights to the 11,998 patients on the practice list. RESULTS--Night visit rates in 15 electoral wards varied from 19.6 to 55.3 visits per 1000 patients per year. The rates showed a significant association with the Townsend score (p = 0.004) and the unemployment rate (p = 0.03) but not with the Jarman score (p = 0.3). The Townsend score explained 49% of the variability; unemployment explained 31% and the Jarman score explained 9%. CONCLUSIONS--Even in a general practice not eligible for deprivation payments there was a 2.8-fold variation in night visit rates between wards. In this practice the Townsend score was significantly better at predicting night visit rates than the Jarman score. This method of looking at internal variation in workloads in computerised practices could give more direct data on the relation between deprivation and general practice workload than has previously been available. PMID:8518606

  16. The relation between sweat rate and weight loss when sweat is dripping off the body

    PubMed Central

    Brebner, D. F.; Kerslake, D. McK.

    1969-01-01

    1. The relation between the rate of sweat production, Ṡ, and the rate of weight loss, Ẇ, has been examined under conditions in which the rate of evaporation was small. 2. Ṡ could be found from Ẇ provided that a film of liquid was maintained over the skin surface. This could be achieved initially by immersing the subject in water containing detergent. Thereafter the film was maintained so long as the rate of weight loss exceeded about 10 g/min. 3. When the rate of weight loss was changing and the rate of evaporation was constant, Ṡ could be calculated as Ẇ + 2·5 Ẅ. 4. When the subject was constantly sprayed with water while being weighed, the correction for Ẅ became negligible. In this case there was no lower limit to the sweat rate which could be measured, but spraying considerably reduced the accuracy of the measurement. 5. The output of sweat from a ventilated capsule on the forearm correlated well with estimates of central sweating drive based on weight measurements corrected for hidromeiosis. PMID:5789946

  17. STAR FORMATION RATES IN MOLECULAR CLOUDS AND THE NATURE OF THE EXTRAGALACTIC SCALING RELATIONS

    SciTech Connect

    Lada, Charles J.; Forbrich, Jan; Lombardi, Marco; Alves, Joao F. E-mail: jforbrich@cfa.harvard.edu E-mail: joao.alves@univie.ac.at

    2012-02-01

    In this paper, we investigate scaling relations between star formation rates and molecular gas masses for both local Galactic clouds and a sample of external galaxies. We specifically consider relations between the star formation rates and measurements of dense, as well as total, molecular gas masses. We argue that there is a fundamental empirical scaling relation that directly connects the local star formation process with that operating globally within galaxies. Specifically, the total star formation rate in a molecular cloud or galaxy is linearly proportional to the mass of dense gas within the cloud or galaxy. This simple relation, first documented in previous studies, holds over a span of mass covering nearly nine orders of magnitude and indicates that the rate of star formation is directly controlled by the amount of dense molecular gas that can be assembled within a star formation complex. We further show that the star formation rates and total molecular masses, characterizing both local clouds and galaxies, are correlated over similarly large scales of mass and can be described by a family of linear star formation scaling laws, parameterized by f{sub DG}, the fraction of dense gas contained within the clouds or galaxies. That is, the underlying star formation scaling law is always linear for clouds and galaxies with the same dense gas fraction. These considerations provide a single unified framework for understanding the relation between the standard (nonlinear) extragalactic Schmidt-Kennicutt scaling law, that is typically derived from CO observations of the gas, and the linear star formation scaling law derived from HCN observations of the dense gas.

  18. Relative rates of growth of annoyance of impulsive and non-impulsive noises.

    PubMed

    Fidell, Sanford; Silvati, Laura; Pearsons, Karl

    2002-01-01

    Twenty-nine people judged the relative annoyance of five variable level signals and 29 impulsive and non-impulsive fixed-level signals in an adaptive paired comparison study. Signals were presented for judgment as heard indoors in a facility capable of accurately reproducing the very low-frequency content of sonic booms. When the annoyance of sonic booms unaccompanied by rattle was compared with that of sounds containing more higher-frequency energy (an aircraft flyover and an octave band of noise centered at 1 kHz), the relative rate of growth of annoyance, as expressed in C-weighted SEL units, was nearly 2:1. In other words, to maintain subjective equality of annoyance, each increase in level of sonic booms had to be matched by nearly twice the increase in level of an aircraft flyover or an octave band of noise centered at 1 kHz. Relative rates of growth of annoyance of sonic booms accompanied by rattle and of non-impulsive sounds, including both low- (63-Hz octave band of noise) and high-frequency energy (1-kHz octave band of noise and an aircraft flyover), were closer to 1:1. Relative rates of growth of annoyance for sonic booms unaccompanied by rattle and low-frequency sounds (63 Hz) were also about 1:1. These differences in relative rates of growth of annoyance of impulsive and non-impulsive sounds are as plausibly attributed to their relative low-frequency content as to impulsiveness per se. It may therefore be more useful for some purposes to express the annoyance of impulsive signals and other environmental noises containing substantial low-frequency energy in terms of effective (duration-corrected) loudness level rather than commonplace ASEL or CSEL. PMID:11837963

  19. Addition by Subtraction: The Relation Between Dropout Rates and School-Level Academic Achievement

    PubMed Central

    GLENNIE, ELIZABETH; BONNEAU, KARA; VANDELLEN, MICHELLE; DODGE, KENNETH A.

    2013-01-01

    Background/Context Efforts to improve student achievement should increase graduation rates. However, work investigating the effects of student-level accountability has consistently demonstrated that increases in the standards for high school graduation are correlated with increases in dropout rates. The most favored explanation for this finding is that high-stakes testing policies that mandate grade repetition and high school exit exams may be the tipping point for students who are already struggling academically. These extra demands may, in fact, push students out of school. Purpose/Objective/Focus This article examines two hypotheses regarding the relation between school-level accountability and dropout rates. The first posits that improvements in school performance lead to improved success for everyone. If school-level accountability systems improve a school for all students, then the proportion of students performing at grade level increases, and the dropout rate decreases. The second hypothesis posits that schools facing pressure to improve their overall accountability score may pursue this increase at the cost of other student outcomes, including dropout rate. Research Design Our approach focuses on the dynamic relation between school-level academic achievement and dropout rates over time—that is, between one year’s achievement and the subsequent year’s dropout rate, and vice versa. This article employs longitudinal data of records on all students in North Carolina public schools over an 8-year period. Analyses employ fixed-effects models clustering schools and districts within years and controls each year for school size, percentage of students who were free/reduced-price lunch eligible, percentage of students who are ethnic minorities, and locale. Findings/Results This study finds partial evidence that improvements in school-level academic performance will lead to improvements (i.e., decreases) in school-level dropout rates. Schools with improved

  20. Age-related changes in the rate of esterification of plasma cholesterol in Fischer-344 rats.

    PubMed

    Carlile, S I; Kudchodkar, B J; Wang, C S; Lacko, A G

    1986-01-01

    Plasma cholesterol and triglyceride levels and selected molecular species of plasma cholesteryl esters and triglycerides were determined in 6-, 12-, 15-, 18-, 21-, and 24-month-old Fischer-344 rats. Lecithin:cholesterol acyltransferase (LCAT) activity was also determined using two independent methods utilizing endogenous and exogenous substrates. Plasma cholesterol levels increased up to 18 months of age and then plateaued. Of the plasma triglyceride molecular species investigated (C50, C52, C54 and C56), only the levels of C52 increased linearly with age. The concentration of other triglyceride molecular species did not change with age. The fractional rate of plasma cholesterol esterification showed a decreasing trend with age, whereas, the net cholesterol esterification rate showed a gradual age related increase. However, this latter parameter remained unchanged with age when the data were normalized for body weight. The cholesterol esterification rates measured using an exogenous substrate (estimating LCAT enzyme levels) showed essentially no change with age. These data indicate that changes in the levels and/or composition of lipoprotein substrate(s) for LCAT are likely causes of the observed age-related changes in the fractional rate of plasma cholesterol esterification. The net esterification rate of plasma cholesterol was significantly correlated with the plasma triglyceride levels when the animals for all age groups were treated as one experimental group. PMID:3959602

  1. Enhanced Atlantic sea-level rise relative to the Pacific under high carbon emission rates

    NASA Astrophysics Data System (ADS)

    Krasting, J. P.; Dunne, J. P.; Stouffer, R. J.; Hallberg, R. W.

    2016-03-01

    Thermal expansion of the ocean in response to warming is an important component of historical sea-level rise. Observational studies show that the Atlantic and Southern oceans are warming faster than the Pacific Ocean. Here we present simulations using a numerical atmospheric-ocean general circulation model with an interactive carbon cycle to evaluate the impact of carbon emission rates, ranging from 2 to 25 GtC yr-1, on basin-scale ocean heat uptake and sea level. For simulations with emission rates greater than 5 GtC yr-1, sea-level rise is larger in the Atlantic than Pacific Ocean on centennial timescales. This basin-scale asymmetry is related to the shorter flushing timescales and weakening of the overturning circulation in the Atlantic. These factors lead to warmer Atlantic interior waters and greater thermal expansion. In contrast, low emission rates of 2 and 3 GtC yr-1 will cause relatively larger sea-level rise in the Pacific on millennial timescales. For a given level of cumulative emissions, sea-level rise is largest at low emission rates. We conclude that Atlantic coastal areas may be particularly vulnerable to near-future sea-level rise from present-day high greenhouse gas emission rates.

  2. Rate coefficients of hydroxyl radical reactions with pesticide molecules and related compounds: A review

    NASA Astrophysics Data System (ADS)

    Wojnárovits, László; Takács, Erzsébet

    2014-03-01

    Rate coefficients published in the literature on hydroxyl radical reactions with pesticides and related compounds are discussed together with the experimental methods and the basic reaction mechanisms. Recommendations are made for the most probable values. Most of the molecules whose rate coefficients are discussed have aromatic ring: their rate coefficients are in the range of 2×109-1×1010 mol-1 dm3 s-1. The rate coefficients show some variation with the electron withdrawing-donating nature of the substituent on the ring. The rate coefficients for triazine pesticides (simazine, atrazine, prometon) are all around 2.5×109 mol-1 dm3 s-1. The values do not show variation with the substituent on the s-triazine ring. The rate coefficients for the non-aromatic molecules which have C=C double bonds or several C-H bonds may also be above 1×109 mol-1 dm3 s-1. However, the values for molecules without C=C double bonds or several C-H bonds are in the 1×107-1×109 mol-1 dm3 s-1 range.

  3. Phonation-related rate coding and recruitment in the genioglossus muscle.

    PubMed

    Shumway, K R; Porfirio, D J; Bailey, E F

    2015-07-01

    Motor unit recruitment was assessed in two muscles with similar muscle fiber-type compositions and that participate in skilled movements: the tongue muscle, genioglossus (GG), and the hand muscle, first dorsal interosseous (FDI). Our primary objectives were to determine in the framework of a voluntary movement whether muscle force is regulated in tongue as it is in limb, i.e., via processes of rate coding and recruitment. Recruitment in the two muscles was assessed within each subject in the context of ramp force (FDI) and in the tongue (GG) during vowel production and specifically, in the context of ramp increases in loudness, and subsequently expressed relative to the maximal. The principle findings of the study are that the general rules of recruitment and rate coding hold true for both GG and FDI, and second, that average firing rates, firing rates at recruitment and peak firing rates in GG are significantly higher than for FDI (P < 0.001) despite tasks performed across comparable force ranges (~2-40 % of max). The higher firing rates observed in the tongue within the context of phonation may be a function of that muscle's dual role as (prime) mover and hydrostatic support element. PMID:25899868

  4. A New Hypothesis for Relative High Rate of Volcanism in the Hesperian on Mars

    NASA Astrophysics Data System (ADS)

    Huang, J.; Li, M.; Xiao, L.; Wang, F.

    2013-12-01

    The rates of impact, weathering, erosion and valley formation on Mars all decreased greatly at the end of the Noachian. However, the average rate of volcanism stayed at a relatively high level throughout the Hesperian. The reason for extensive lava plains in the Hesperian is intriguing, since the rate of volcanism in the later time should have decreased dramatically than earlier time due to decreasing of internal thermal energy. Recent modeling results brought up 'cold and icy' against the prevalent 'warm and wet' for the early Mars, which showed tens to hundreds meters thick ice covered the Noachian highlands at a very limited total water inventory in 40 martian years. However, the thickness of ice could be much larger considering the enormous amount of water which created the channels and valleys on martian surface. In Iceland of Earth, both observation and numerical modeling results show that the great increase of rate of volcanism in the 1000-year time scale could be a result of ice sheet melting. Inspired from what has happened in Iceland, in this study, we are going to investigate the possibility of increasing the rates of volcanism by deglaciation in the Hesperian time. Our hypothesis is that the high rates of volcanism in Hesperian of Mars could also be the result of deglaciation.

  5. Distributed patterns of event-related potentials predict subsequent ratings of abstract stimulus attributes.

    PubMed

    Bode, Stefan; Bennett, Daniel; Stahl, Jutta; Murawski, Carsten

    2014-01-01

    Exposure to pleasant and rewarding visual stimuli can bias people's choices towards either immediate or delayed gratification. We hypothesised that this phenomenon might be based on carry-over effects from a fast, unconscious assessment of the abstract 'time reference' of a stimuli, i.e. how the stimulus relates to one's personal understanding and connotation of time. Here we investigated whether participants' post-experiment ratings of task-irrelevant, positive background visual stimuli for the dimensions 'arousal' (used as a control condition) and 'time reference' were related to differences in single-channel event-related potentials (ERPs) and whether they could be predicted from spatio-temporal patterns of ERPs. Participants performed a demanding foreground choice-reaction task while on each trial one task-irrelevant image (depicting objects, people and scenes) was presented in the background. Conventional ERP analyses as well as multivariate support vector regression (SVR) analyses were conducted to predict participants' subsequent ratings. We found that only SVR allowed both 'arousal' and 'time reference' ratings to be predicted during the first 200 ms post-stimulus. This demonstrates an early, automatic semantic stimulus analysis, which might be related to the high relevance of 'time reference' to everyday decision-making and preference formation. PMID:25271850

  6. Distributed Patterns of Event-Related Potentials Predict Subsequent Ratings of Abstract Stimulus Attributes

    PubMed Central

    Bode, Stefan; Bennett, Daniel; Stahl, Jutta; Murawski, Carsten

    2014-01-01

    Exposure to pleasant and rewarding visual stimuli can bias people's choices towards either immediate or delayed gratification. We hypothesised that this phenomenon might be based on carry-over effects from a fast, unconscious assessment of the abstract ‘time reference’ of a stimuli, i.e. how the stimulus relates to one's personal understanding and connotation of time. Here we investigated whether participants' post-experiment ratings of task-irrelevant, positive background visual stimuli for the dimensions ‘arousal’ (used as a control condition) and ‘time reference’ were related to differences in single-channel event-related potentials (ERPs) and whether they could be predicted from spatio-temporal patterns of ERPs. Participants performed a demanding foreground choice-reaction task while on each trial one task-irrelevant image (depicting objects, people and scenes) was presented in the background. Conventional ERP analyses as well as multivariate support vector regression (SVR) analyses were conducted to predict participants' subsequent ratings. We found that only SVR allowed both ‘arousal’ and ‘time reference’ ratings to be predicted during the first 200 ms post-stimulus. This demonstrates an early, automatic semantic stimulus analysis, which might be related to the high relevance of ‘time reference’ to everyday decision-making and preference formation. PMID:25271850

  7. Injecting drug users in Scotland, 2006: Listing, number, demography, and opiate-related death-rates.

    PubMed

    King, Ruth; Bird, Sheila M; Overstall, Antony; Hay, Gordon; Hutchinson, Sharon J

    2013-06-01

    Using Bayesian capture-recapture analysis, we estimated the number of current injecting drug users (IDUs) in Scotland in 2006 from the cross-counts of 5670 IDUs listed on four data-sources: social enquiry reports (901 IDUs listed), hospital records (953), drug treatment agencies (3504), and recent Hepatitis C virus (HCV) diagnoses (827 listed as IDU-risk). Further, we accessed exact numbers of opiate-related drugs-related deaths (DRDs) in 2006 and 2007 to improve estimation of Scotland's DRD rates per 100 current IDUs. Using all four data-sources, and model-averaging of standard hierarchical log-linear models to allow for pairwise interactions between data-sources and/or demographic classifications, Scotland had an estimated 31700 IDUs in 2006 (95% credible interval: 24900-38700); but 25000 IDUs (95% CI: 20700-35000) by excluding recent HCV diagnoses whose IDU-risk can refer to past injecting. Only in the younger age-group (15-34 years) were Scotland's opiate-related DRD rates significantly lower for females than males. Older males' opiate-related DRD rate was 1.9 (1.24-2.40) per 100 current IDUs without or 1.3 (0.94-1.64) with inclusion of recent HCV diagnoses. If, indeed, Scotland had only 25000 current IDUs in 2006, with only 8200 of them aged 35+ years, the opiate-related DRD rate is higher among this older age group than has been appreciated hitherto. There is counter-balancing good news for the public health: the hitherto sharp increase in older current IDUs had stalled by 2006. PMID:23730265

  8. The influence of fatigue-induced increase in relative work rate on temperature regulation during exercise.

    PubMed

    Kacin, Alan; Golja, Petra; Tipton, Michael J; Eiken, Ola; Mekjavic, Igor B

    2008-05-01

    Heat-loss responses during steady-load exercise are affected by an increase in relative work rate induced by muscle ischaemia or hypoxaemia. The present study investigated whether progressive increases in perception of exertion and relative oxygen uptake %VO2peak which occur during prolonged steady-load exercise as a result of progressively increased peripheral fatigue, might also affect the regulation of heat loss responses and hence the exercise-induced increase in mean body temperature. Ten male subjects first performed a ramp-test to exhaustion on a cycle ergometer to evaluate their initial peak oxygen uptake (Control VO2peak). On a separate day, 120 min of cycling at constant power output corresponding to 60% of Control VO2peak was performed in thermoneutral environment (Ta = 23 degrees C, RH = 50%, wind speed = 5 m s(-1)). This was immediately followed by another maximal performance test (Fatigue VO2peak). During prolonged exercise, median (range) rating of perceived exertion for whole-body (RPEwb) increased (P < 0.01) from initial 3.5 (1-5) to 5.5 (5-9) at the end of exercise. Fatigue VO2peak and peak power output were 9 (5) and 10 (5)% lower (P < 0.01) when compared to control values. At the onset of exercise, heat production, mechanical efficiency, heat loss and mean body temperature increased towards asymptotic values, thereafter remained constant throughout the 120 min exercise, despite the concomitant progressive increase in relative work rate, as reflected in increased RPEwb and relative oxygen uptake. It is thus concluded that the increase in relative work rate induced predominantly by peripheral muscle fatigue affects neither the level of increase in mean body temperature nor the regulation of heat loss responses during prolonged steady-load exercise. PMID:18202847

  9. Degree of mutual ornamentation in birds is related to divorce rate.

    PubMed

    Kraaijeveld, Ken

    2003-09-01

    Many bird species have ornaments that are expressed equally in both sexes. I use comparative analysis to investigate why some monomorphic birds are highly ornamented, whereas others are drab. The results show a significant positive association between the degree of mutual ornamentation and divorce rate. This result is robust to the removal of the effects of phylogeny, site fidelity, residency, coloniality, nest type, mortality, body size and body-size dimorphism. The level of extra-pair paternity was not related to the degree of mutual ornamentation. I argue that these results are compatible with a process of mutual sexual selection, in which both sexes compete for access to mates. The coupled evolution of ornamentation and divorce rate, from the probable ancestral state of a high degree of ornamentation and a low divorce rate, appears to result mainly from a loss of ornamentation under mate fidelity. PMID:12964980

  10. Degree of mutual ornamentation in birds is related to divorce rate.

    PubMed Central

    Kraaijeveld, Ken

    2003-01-01

    Many bird species have ornaments that are expressed equally in both sexes. I use comparative analysis to investigate why some monomorphic birds are highly ornamented, whereas others are drab. The results show a significant positive association between the degree of mutual ornamentation and divorce rate. This result is robust to the removal of the effects of phylogeny, site fidelity, residency, coloniality, nest type, mortality, body size and body-size dimorphism. The level of extra-pair paternity was not related to the degree of mutual ornamentation. I argue that these results are compatible with a process of mutual sexual selection, in which both sexes compete for access to mates. The coupled evolution of ornamentation and divorce rate, from the probable ancestral state of a high degree of ornamentation and a low divorce rate, appears to result mainly from a loss of ornamentation under mate fidelity. PMID:12964980

  11. The relationship between relative solvent accessibility and evolutionary rate in protein evolution.

    PubMed

    Ramsey, Duncan C; Scherrer, Michael P; Zhou, Tong; Wilke, Claus O

    2011-06-01

    Recent work with Saccharomyces cerevisiae shows a linear relationship between the evolutionary rate of sites and the relative solvent accessibility (RSA) of the corresponding residues in the folded protein. Here, we aim to develop a mathematical model that can reproduce this linear relationship. We first demonstrate that two models that both seem reasonable choices (a simple model in which selection strength correlates with RSA and a more complex model based on RSA-dependent amino acid distributions) fail to reproduce the observed relationship. We then develop a model on the basis of observed site-specific amino acid distributions and show that this model behaves appropriately. We conclude that evolutionary rates are directly linked to the distribution of amino acids at individual sites. Because of this link, any future insight into the biophysical mechanisms that determine amino acid distributions will improve our understanding of evolutionary rates. PMID:21467571

  12. Muscle contraction: energy rate equations in relation to efficiency and step-size distance.

    PubMed

    Worthington, C R; Elliott, G F

    2003-09-01

    We derive the energy rate equation for muscle contraction. Our equation has only two parameters m, the maintenance heat rate and 1/S, the shortening heat coefficient. The impulsive model (previously described in earlier papers) provides a physical basis for parameter 1/S as well as for constants a and b in Hill's force-velocity equation. We develop new theory and relate the efficiency and the step-size distance to our energy rate equation. Correlation between the efficiency and the step-size distance is established. The various numbers are listed in Table 1: we use data from five different muscles in the literature. In summary, our analysis strongly supports the impulsive model as the correct model of contraction. PMID:12957311

  13. Heart rate-left ventricular ejection time relations - Variations during postural change and cardiovascular challenges

    NASA Technical Reports Server (NTRS)

    Lance, V. Q.; Spodick, D. H.

    1976-01-01

    Experiments were conducted on healthy human subjects to determine HR-LVET (Heart Rate-Left Ventricular Ejection Time) regression relations in different postures, including tilt, and during isometric exercise. The subjects were tested in the resting state in supine and sitting positions, during isometric handgrip in supine and sitting positions and during 70 deg headup tilt. The recordings included a bipolar electrocardiogram and a right external carotid pulse curve. Comparison of the HR-LVET relation for the conditions under analysis revealed differences among the respective regression equations, which can be explained by the well-established differences in stroke volume and ejection rate among these states. These differences appear to account for the fact that under conditions in which stroke volume variations should be the major determinant, slopes will be similar but intercepts will vary. Since substantial differences among intercepts are observed, caution should be exercised whenever the intercept factor is used to predict LVET for HR.

  14. Relative rates of coke formation from hydrocarbons in steam cracking of naphtha: 3. Aromatic hydrocarbons

    SciTech Connect

    Kopinke, F. . Section of Remediation Research); Zimmermann, G. ); Reyniers, G.C.; Froment, G.F. )

    1993-11-01

    Relative rate constants of coke formation (k) from 18 aromatic hydrocarbons during steam cracking of naphtha at 810 C were determined by application of [sup 14]C-labeled compounds. Benzene is a poor coke precursor (k = 0.3), whereas polycyclic structures like acenaphthylene, anthracene, and chrysene have a high coking potential in the pyrolysis reactor (k = 4.5--6) as well as in the TLE section (k = 12--30). The relation between structure and coke formation rate of aromatic hydrocarbons can be interpreted on the basis of their reactivity in radical reactions. Constituents of the fuel fraction ([ge] C[sub 9]) derived from nonaromatic feed components are more efficient in the TLE fouling than those stemming from benzene derivatives.

  15. THE OBSERVED RELATION BETWEEN STELLAR MASS, DUST EXTINCTION, AND STAR FORMATION RATE IN LOCAL GALAXIES

    SciTech Connect

    Zahid, H. J.; Kewley, L. J.; Kudritzki, R. P.; Yates, R. M.

    2013-02-15

    In this study, we investigate the relation between stellar mass, dust extinction, and star formation rate (SFR) using {approx}150,000 star-forming galaxies from SDSS DR7. We show that the relation between dust extinction and SFR changes with stellar mass. For galaxies at the same stellar mass, dust extinction is anti-correlated with the SFR at stellar masses <10{sup 10} M {sub Sun }. There is a sharp transition in the relation at a stellar mass of 10{sup 10} M {sub Sun }. At larger stellar masses, dust extinction is positively correlated with the SFR for galaxies at the same stellar mass. The observed relation between stellar mass, dust extinction, and SFR presented in this study helps to confirm similar trends observed in the relation between stellar mass, metallicity, and SFR. The relation reported in this study provides important new constraints on the physical processes governing the chemical evolution of galaxies. The correlation between SFR and dust extinction for galaxies with stellar masses >10{sup 10} M {sub Sun} is shown to extend to the population of quiescent galaxies suggesting that the physical processes responsible for the observed relation between stellar mass, dust extinction, and SFR may be related to the processes leading to the shutdown of star formation in galaxies.

  16. The relation between recombination rate and patterns of molecular evolution and variation in Drosophila melanogaster.

    PubMed

    Campos, José L; Halligan, Daniel L; Haddrill, Penelope R; Charlesworth, Brian

    2014-04-01

    Genetic recombination associated with sexual reproduction increases the efficiency of natural selection by reducing the strength of Hill-Robertson interference. Such interference can be caused either by selective sweeps of positively selected alleles or by background selection (BGS) against deleterious mutations. Its consequences can be studied by comparing patterns of molecular evolution and variation in genomic regions with different rates of crossing over. We carried out a comprehensive study of the benefits of recombination in Drosophila melanogaster, both by contrasting five independent genomic regions that lack crossing over with the rest of the genome and by comparing regions with different rates of crossing over, using data on DNA sequence polymorphisms from an African population that is geographically close to the putatively ancestral population for the species, and on sequence divergence from a related species. We observed reductions in sequence diversity in noncrossover (NC) regions that are inconsistent with the effects of hard selective sweeps in the absence of recombination. Overall, the observed patterns suggest that the recombination rate experienced by a gene is positively related to an increase in the efficiency of both positive and purifying selection. The results are consistent with a BGS model with interference among selected sites in NC regions, and joint effects of BGS, selective sweeps, and a past population expansion on variability in regions of the genome that experience crossing over. In such crossover regions, the X chromosome exhibits a higher rate of adaptive protein sequence evolution than the autosomes, implying a Faster-X effect. PMID:24489114

  17. Age-related increase of resting metabolic rate in the human brain

    PubMed Central

    Peng, Shin-Lei; Dumas, Julie A.; Park, Denise C.; Liu, Peiying; Filbey, Francesca M.; McAdams, Carrie J.; Pinkham, Amy E.; Adinoff, Bryon; Zhang, Rong; Lu, Hanzhang

    2014-01-01

    With age, many aspects of the brain structure undergo a pronounced decline, yet individuals generally function well until advanced old age. There appear to be several compensatory mechanisms in brain aging, but their precise nature is not well characterized. Here we provide evidence that the brain of older adults expends more energy when compared to younger adults, as manifested by an age-related increase (P=0.03) in cerebral metabolic rate of oxygen (CMRO2) (N=118, men=56, ages 18 to 74). We further showed that, before the mean menopausal age of 51 years old, female and male groups have similar rates of CMRO2 increase (P=0.015) and there was no interaction between age and sex effects (P=0.85). However, when using data from the entire age range, women have a slower rate of CMRO2 change when compared to men (P<0.001 for age × sex interaction term). Thus, menopause and estrogen level may have played a role in this sex difference. Our data also revealed a possible circadian rhythm of CMRO2 in that brain metabolic rate is greater at noon than in the morning (P=0.02). This study reveals a potential neurobiological mechanism for age-related compensation in brain function and also suggests a sex-difference in its temporal pattern. PMID:24814209

  18. Temperature and rainfall are related to fertility rate after spring artificial insemination in small ruminants

    NASA Astrophysics Data System (ADS)

    Abecia, J. A.; Arrébola, F.; Macías, A.; Laviña, A.; González-Casquet, O.; Benítez, F.; Palacios, C.

    2016-03-01

    A total number of 1092 artificial inseminations (AIs) performed from March to May were documented over four consecutive years on 10 Payoya goat farms (36° N) and 19,392 AIs on 102 Rasa Aragonesa sheep farms (41° N) over 10 years. Mean, maximum, and minimum ambient temperatures, mean relative humidity, mean solar radiation, and total rainfall on each insemination day were recorded. Overall, fertility rates were 58 % in goats and 45 % in sheep. The fertility rates of the highest and lowest deciles of each of the meteorological variables indicated that temperature and rainfall had a significant effect on fertility in goats. Specifically, inseminations that were performed when mean (68 %), maximum (68 %), and minimum (66 %) temperatures were in the highest decile, and rainfall was in the lowest decile (59 %), had a significantly (P < 0.0001) higher proportion of does that became pregnant than did the ewes in the lowest decile (56, 54, 58, and 49 %, respectively). In sheep, the fertility rates of the highest decile of mean (62 %), maximum (62 %), and minimum (52 %) temperature, RH (52 %), THI (53 %), and rainfall (45 %) were significantly higher (P < 0.0001) than were the fertility rates among ewes in the lowest decile (46, 45, 45, 45, 46, and 43 %, respectively). In conclusion, weather was related to fertility in small ruminants after AI in spring. It remains to be determined whether scheduling the dates of insemination based on forecasted temperatures can improve the success of AI in goats and sheep.

  19. Conscientiousness mediates the relation between perceived parental socialisation and self-rated health

    PubMed Central

    Takahashi, Yusuke; Roberts, Brent W.; Hoshino, Takahiro

    2013-01-01

    The pathways between parenting behaviours, personality and physical health have all been separately studied. Prior research has paid little attention to the indirect effects of personality in the path between parenting behaviours and better health. The purpose of this study was to explore the mediational effects of conscientiousness on the relationships between parental socialisation of responsibility and self-rated health, and to examine potential age differences in this mediational pathway. In total, 736 female and 749 male members across Japan participated in this study. They were divided into three groups by age category: younger-, middle-aged and older-aged. Conscientiousness and health were concurrently rated, while parental socialisation of responsibility was retrospectively assessed. Our analyses revealed that parental socialisation of responsibility is positively associated with conscientiousness and self-rated health, that conscientiousness is positively associated with self-rated health, and that conscientiousness fully mediated the effect of parental socialisation of responsibility on self-rated health. The mediational links were consistent across younger, middle-aged and older-aged cohorts. Our findings suggest that greater parental socialisation of responsibility relates to higher conscientiousness, and consequently healthier adults. These findings imply that parental behaviours could be a plausible target for intervention to foster the development of conscientiousness and better health. PMID:22292501

  20. The sonochemical degradation of azobenzene and related azo dyes: Rate enhancements via Fenton's reactions

    SciTech Connect

    Joseph, J.M.; Destaillats, H.; Hung, H.M.; Hoffmann, M.R.

    2000-01-20

    The sonochemical degradation of aqueous solutions of azobenzene and related azo dyes (methyl orange, o-methyl red, and p-methyl red) was performed at 500 kHz and 50 W, under air, O{sub 2}, or Ar saturation at 288 K. Reaction products and intermediates were identified by HPLC-ES-MS. Total organic carbon (TOC) was also determined as a function of reaction time. The authors propose a reaction mechanism based on the observed species and the extent and rate of TOC depletion. The effects of the dye structures and of the background gas on the sonochemical bleaching rates were also investigated. The reaction rates for o-methyl red were approximately 30--40% faster than those for the other compounds. Saturating with Ar instead of air or O{sub 2} increased the pseudo first-order rate constants for the degradation by 10%. The acceleration of the sonochemical bleaching and the mineralization process upon addition of Fe(II) was also investigated in Ar-saturated methyl orange solutions. A 3-fold increase in the reaction rate was observed at optimal Fe(II) concentrations. This kinetic effect is quantitatively accounted for by a simple kinetic model based on the reaction of Fe(II) with sonochemically produced H{sub 2}O{sub 2} (Fenton's reaction). This latter effect illustrates a simple way of achieving a substantial improvement in the efficiency of sonochemical degradation reactions.

  1. Relative Reinforcer Rates and Magnitudes Do Not Control Concurrent Choice Independently

    PubMed Central

    Elliffe, Douglas; Davison, Michael; Landon, Jason

    2008-01-01

    One assumption of the matching approach to choice is that different independent variables control choice independently of each other. We tested this assumption for reinforcer rate and magnitude in an extensive parametric experiment. Five pigeons responded for food reinforcement on switching-key concurrent variable-interval variable-interval schedules. Across conditions, the ratios of reinforcer rates and of reinforcer magnitudes on the two alternatives were both manipulated. Control by each independent variable, as measured by generalized-matching sensitivity, changed significantly with the ratio of the other independent variable. Analyses taking the model-comparison approach, which weighs improvement in goodness-of-fit against increasing number of free parameters, were inconclusive. These analyses compared a model assuming constant sensitivity to magnitude across all reinforcer-rate ratios with two alternative models. One of those alternatives allowed sensitivity to magnitude to vary freely across reinforcer-rate ratios, and was less efficient than the common-sensitivity model for all pigeons, according to the Schwarz-Bayes information criterion. The second alternative model constrained sensitivity to magnitude to be equal for pairs of reinforcer-rate ratios that deviated from unity by proportionately equal amounts but in opposite directions. This model was more efficient than the common-magnitude-sensitivity model for 2 of the pigeons, but not for the other 3. An analysis of variance, carried out independently of the generalized-matching analysis, also showed a significant interaction between the effects of reinforcer rate and reinforcer magnitude on choice. On balance, these results suggest that the assumption of independence inherent in the matching approach cannot be maintained. Relative reinforcer rates and magnitudes do not control choice independently. PMID:18831124

  2. Jackknife-corrected parametric bootstrap estimates of growth rates in bivalve mollusks using nearest living relatives.

    PubMed

    Dexter, Troy A; Kowalewski, Michał

    2013-12-01

    Quantitative estimates of growth rates can augment ecological and paleontological applications of body-size data. However, in contrast to body-size estimates, assessing growth rates is often time-consuming, expensive, or unattainable. Here we use an indirect approach, a jackknife-corrected parametric bootstrap, for efficient approximation of growth rates using nearest living relatives with known age-size relationships. The estimate is developed by (1) collecting a sample of published growth rates of closely related species, (2) calculating the average growth curve using those published age-size relationships, (3) resampling iteratively these empirically known growth curves to estimate the standard errors and confidence bands around the average growth curve, and (4) applying the resulting estimate of uncertainty to bracket age-size relationships of the species of interest. This approach was applied to three monophyletic families (Donacidae, Mactridae, and Semelidae) of mollusk bivalves, a group characterized by indeterministic shell growth, but widely used in ecological, paleontological, and geochemical research. The resulting indirect estimates were tested against two previously published geochemical studies and, in both cases, yielded highly congruent age estimates. In addition, a case study in applied fisheries was used to illustrate the potential of the proposed approach for augmenting aquaculture management practices. The resulting estimates of growth rates place body size data in a constrained temporal context and confidence intervals associated with resampling estimates allow for assessing the statistical uncertainty around derived temporal ranges. The indirect approach should allow for improved evaluation of diverse research questions, from sustainability of industrial shellfish harvesting to climatic interpretations of stable isotope proxies extracted from fossil skeletons. PMID:24071629

  3. Are beach erosion rates and sea-level rise related in Hawaii?

    NASA Astrophysics Data System (ADS)

    Romine, Bradley M.; Fletcher, Charles H.; Barbee, Matthew M.; Anderson, Tiffany R.; Frazer, L. Neil

    2013-09-01

    The islands of Oahu and Maui, Hawaii, with significantly different rates of localized sea-level rise (SLR, approximately 65% higher rate on Maui) over the past century due to lithospheric flexure and/or variations in upper ocean water masses, provide a unique setting to investigate possible relations between historical shoreline changes and SLR. Island-wide and regional historical shoreline trends are calculated for the islands using shoreline positions measured from aerial photographs and survey charts. Historical shoreline data are optimized to reduce anthropogenic influences on shoreline change measurements. Shoreline change trends are checked for consistency using two weighted regression methods and by systematic exclusion of coastal regions based on coastal aspect (wave exposure) and coastal geomorphology. Maui experienced the greatest extent of beach erosion over the past century with 78% percent of beaches eroding compared to 52% on Oahu. Maui also had a significantly higher island-wide average shoreline change rate at - 0.13 ± 0.05 m/yr compared to Oahu at - 0.03 ± 0.03 m/yr (at the 95% Confidence Interval). Differing rates of relative SLR around Oahu and Maui remain as the best explanation for the difference in overall shoreline trends after examining other influences on shoreline change including waves, sediment supply and littoral processes, and anthropogenic changes; though, these other influences certainly remain important to shoreline change in Hawaii. The results of this study show that SLR is an important factor in historical shoreline change in Hawaii and that historical rates of shoreline change are about two orders of magnitude greater than SLR.

  4. The evolution of HPV-related anogenital cancers reported in Quebec - incidence rates and survival probabilities.

    PubMed

    Louchini, R; Goggin, P; Steben, M

    2008-01-01

    Non-cervical anogenital cancers (i.e. anal, vulvar, vaginal and penile cancers) associated with the human papillomavirus (HPV), for which HPV is known to be the necessary cause of carcinogenesis, are poorly documented due to their relatively low incidence rate. The aim of this study is to describe the incidence rates of these cancers between 1984 and 2001, and their relative survival probabilities, in Quebec (Canada) between 1984 and 1998. The incidence of these cancers is on the rise, particularly anal cancer in women and, more recently (since 1993-95), vulvar cancer. Between 1984-86 and 1993-95, the 5-year relative survival probability for men with anal cancer decreased from 57% to 46%, while that for penile cancer dropped from 75% to 59%. However, during the same period, the 5-year relative survival probability for women with anal cancer rose from 56% to 65%, and remained stable for cervical and vulvar cancers, at 74% and 82%, respectively. PMID:18341764

  5. Systematic Variation of Observed Radar Reflectivity-Rainfall Rate Relations in the Tropics.

    NASA Astrophysics Data System (ADS)

    Amitai, Eyal

    2000-12-01

    The Tropical Rainfall Measuring Mission Global Validation Program provides a unique opportunity to compare radar datasets from different sites, because they are analyzed in a relatively uniform procedure. Monthly observed radar reflectivity-rainfall rate (Ze-R) relations for four different sites that are surrounded by tipping bucket gauge networks (Melbourne, Florida; Houston, Texas; Darwin, Australia; and Kwajalein Atoll, Republic of Marshall Islands) were derived. The radar and gauge data from all sites are controlled for quality using the same algorithms, which also include an automated procedure to filter unreliable rain gauge data upon comparison with radar data. The relations are generated by two different methods. The first method is based on using a power law Ze-R with a fixed exponent of 1.4, and the second is based on matching unconditional probabilities of rain rates as measured by the gauge to radar-observed reflectivities and is known as the window probability matching method (WPMM). Both methods tune the radar observations to a network of quality-controlled gauges to adjust the total monthly rainfall to match the gauges. Separate relations are generated for convective and stratiform rain, as classified by the horizontal reflectivity structure.In the WPMM-based Ze-R relations, a given Ze was matched to a much lower R in convective rainfall than in stratiform rainfall. These relations were found to be curved lines in log-log space rather than a straight-line power law. The WPMM-based Ze-R curves demonstrated systematic variation between the convective and stratiform rain, but the power law-based Ze-R curves showed no systematic trend. The systematic variation in the relations shown here contradicts previous findings in which the classification is based only on the existence or nonexistence of brightband signature. The latter indicates a higher reflectivity in stratiform rain as compared with that in convective rain, for a given rain rate. Recent studies

  6. Climatologically tuned reflectivity-rain rate relations and links to area-time integrals

    NASA Technical Reports Server (NTRS)

    Atlas, David; Rosenfeld, Daniel; Wolff, David B.

    1990-01-01

    An effort is made to determine relationships between reflectivity (Z) and rain rate (R) which are tuned to the local climatology. The development of such relations was motivated by the need to understand the role of precipitation in controlling general circulation and in affecting such phenomena as ENSO. Attention is given to methods of deriving such relations and how they are linked to area integral rainfall measurements. In essence, the relation is tuned so that the probability distribution of reflectivity, P(Z), replicates that of R over some predetermined space-time climatic domain. Thus, the accurate measurement of the average R over any smaller domain depends on how closely the sampled P(Z) approximates the climatic P(Z). The probability matching method used is a modification of the approach of Calheiros and Zawadzki (1987) and Rosenfeld (1980). The technique is applied to data from Germany and the eastern tropical Atlantic (GATE).

  7. Evaluating Abstract Art: Relation between Term Usage, Subjective Ratings, Image Properties and Personality Traits

    PubMed Central

    Lyssenko, Nathalie; Redies, Christoph; Hayn-Leichsenring, Gregor U.

    2016-01-01

    One of the major challenges in experimental aesthetics is the uncertainty of the terminology used in experiments. In this study, we recorded terms that are spontaneously used by participants to describe abstract artworks and studied their relation to the second-order statistical image properties of the same artworks (Experiment 1). We found that the usage frequency of some structure-describing terms correlates with statistical image properties, such as PHOG Self-Similarity, Anisotropy and Complexity. Additionally, emotion-associated terms correlate with measured color values. Next, based on the most frequently used terms, we created five different rating scales (Experiment 2) and obtained ratings of participants for the abstract paintings on these scales. We found significant correlations between descriptive score ratings (e.g., between structure and subjective complexity), between evaluative and descriptive score ratings (e.g., between preference and subjective complexity/interest) and between descriptive score ratings and statistical image properties (e.g., between interest and PHOG Self-Similarity, Complexity and Anisotropy). Additionally, we determined the participants’ personality traits as described in the ‘Big Five Inventory’ (Goldberg, 1990; Rammstedt and John, 2005) and correlated them with the ratings and preferences of individual participants. Participants with higher scores for Neuroticism showed preferences for objectively more complex images, as well as a different notion of the term complex when compared with participants with lower scores for Neuroticism. In conclusion, this study demonstrates an association between objectively measured image properties and the subjective terms that participants use to describe or evaluate abstract artworks. Moreover, our results suggest that the description of abstract artworks, their evaluation and the preference of participants for their low-level statistical properties are linked to personality traits

  8. Evaluating Abstract Art: Relation between Term Usage, Subjective Ratings, Image Properties and Personality Traits.

    PubMed

    Lyssenko, Nathalie; Redies, Christoph; Hayn-Leichsenring, Gregor U

    2016-01-01

    One of the major challenges in experimental aesthetics is the uncertainty of the terminology used in experiments. In this study, we recorded terms that are spontaneously used by participants to describe abstract artworks and studied their relation to the second-order statistical image properties of the same artworks (Experiment 1). We found that the usage frequency of some structure-describing terms correlates with statistical image properties, such as PHOG Self-Similarity, Anisotropy and Complexity. Additionally, emotion-associated terms correlate with measured color values. Next, based on the most frequently used terms, we created five different rating scales (Experiment 2) and obtained ratings of participants for the abstract paintings on these scales. We found significant correlations between descriptive score ratings (e.g., between structure and subjective complexity), between evaluative and descriptive score ratings (e.g., between preference and subjective complexity/interest) and between descriptive score ratings and statistical image properties (e.g., between interest and PHOG Self-Similarity, Complexity and Anisotropy). Additionally, we determined the participants' personality traits as described in the 'Big Five Inventory' (Goldberg, 1990; Rammstedt and John, 2005) and correlated them with the ratings and preferences of individual participants. Participants with higher scores for Neuroticism showed preferences for objectively more complex images, as well as a different notion of the term complex when compared with participants with lower scores for Neuroticism. In conclusion, this study demonstrates an association between objectively measured image properties and the subjective terms that participants use to describe or evaluate abstract artworks. Moreover, our results suggest that the description of abstract artworks, their evaluation and the preference of participants for their low-level statistical properties are linked to personality traits. PMID

  9. Genome Size Evolution in Relation to Leaf Strategy and Metabolic Rates Revisited

    PubMed Central

    Beaulieu, Jeremy M.; Leitch, Ilia J.; Knight, Charles A.

    2007-01-01

    Background and Aims It has been proposed that having too much DNA may carry physiological consequences for plants. The strong correlation between DNA content, cell size and cell division rate could lead to predictable morphological variation in plants, including a negative relationship with leaf mass per unit area (LMA). In addition, the possible increased demand for resources in species with high DNA content may have downstream effects on maximal metabolic efficiency, including decreased metabolic rates. Methods Tests were made for genome size-dependent variation in LMA and metabolic rates (mass-based photosynthetic rate and dark respiration rate) using our own measurements and data from a plant functional trait database (Glopnet). These associations were tested using two metrics of genome size: bulk DNA amount (2C DNA) and monoploid genome size (1Cx DNA). The data were analysed using an evolutionary framework that included a regression analysis and independent contrasts using a phylogenetic tree with estimates of molecular diversification times. A contribution index for the LMA data set was also calculated to determine which divergences have the greatest influence on the relationship between genome size and LMA. Key Results and Conclusions A significant negative association was found between bulk DNA amount and LMA in angiosperms. This was primarily a result of influential divergences that may represent early shifts in growth form. However, divergences in bulk DNA amount were positively associated with divergences in LMA, suggesting that the relationship may be indirect and mediated through other traits directly related to genome size. There was a significant negative association between genome size and metabolic rates that was driven by a basal divergence between angiosperms and gymnosperms; no significant independent contrast results were found. Therefore, it is concluded that genome size-dependent constraints acting on metabolic efficiency may not exist within

  10. Relation of ongoing deformation rates to the subduction zone process in southern Alaska

    NASA Astrophysics Data System (ADS)

    Sauber, Jeanne; McClusky, Simon; King, Robert

    1997-11-01

    The rate and orientation of ongoing strain associated with subduction of the Pacific plate and the accretion of the Yakutat terrane to southern Alaska has been estimated at 13 sites from Global Positioning System measurements made in June 1993 and 1995. Along the Gulf of Alaska coast near Cape Yakataga, the average rate of deformation, relative to Fairbanks, was ≈38 mm/yr at N32°W. Further inland, above the region where the dip of the downgoing Pacific plate changes from about 10° to >30°, the deformation rate was ≈12mm/yr at N26°W. In the Sourdough/Paxson area, the deformation rate drops to 2-5 mm/yr and suggests a low short-term deformation rate across the Denali fault. Elastic straining of the overriding plate due to back-slip on a main thrust zone with an average dip of about 10° can account for the overall rate and distribution of short-term compressional strain across south central Alaska. Above the transitional region between unstable and stable sliding we suggest that strain associated with ≈15 mm/yr of right-lateral strike-slip occurs also. If the strain accumulated since the two 1899 earthquakes (both MW=8.1) from the offshore Pamplona fault zone to south of the Border Ranges fault (down-dip width ≈100 km) was seismically released on a single fault it would correspond to a M=8.1 earthquake.

  11. Exploring Systematic Effects in the Relation Between Stellar Mass, Gas Phase Metallicity, and Star Formation Rate

    NASA Astrophysics Data System (ADS)

    Telford, O. Grace; Dalcanton, Julianne J.; Skillman, Evan D.; Conroy, Charlie

    2016-08-01

    There is evidence that the well-established mass–metallicity relation in galaxies is correlated with a third parameter: star formation rate (SFR). The strength of this correlation may be used to disentangle the relative importance of different physical processes (e.g., infall of pristine gas, metal-enriched outflows) in governing chemical evolution. However, all three parameters are susceptible to biases that might affect the observed strength of the relation between them. We analyze possible sources of systematic error, including sample bias, application of signal-to-noise ratio cuts on emission lines, choice of metallicity calibration, uncertainty in stellar mass determination, aperture effects, and dust. We present the first analysis of the relation between stellar mass, gas phase metallicity, and SFR using strong line abundance diagnostics from Dopita et al. for ∼130,000 star-forming galaxies in the Sloan Digital Sky Survey and provide a detailed comparison of these diagnostics in an appendix. Using these new abundance diagnostics yields a 30%–55% weaker anti-correlation between metallicity and SFR at fixed stellar mass than that reported by Mannucci et al. We find that, for all abundance diagnostics, the anti-correlation with SFR is stronger for the relatively few galaxies whose current SFRs are elevated above their past average SFRs. This is also true for the new abundance diagnostic of Dopita et al., which gives anti-correlation between Z and SFR only in the high specific star formation rate (sSFR) regime, in contrast to the recent results of Kashino et al. The poorly constrained strength of the relation between stellar mass, metallicity, and SFR must be carefully accounted for in theoretical studies of chemical evolution.

  12. A retrospective study on related factors affecting the survival rate of dental implants

    PubMed Central

    Kang, Jeong-Kyung; Lee, Ki; Lee, Yong-Sang; Park, Pil-Kyoo

    2011-01-01

    PURPOSE The aim of this retrospective study is to analyze the relationship between local factors and survival rate of dental implant which had been installed and restored in Seoul Veterans Hospital dental center for past 10 years. And when the relationship is found out, it could be helpful to predict the prognosis of dental implants. MATERIALS AND METHODS A retrospective study of patients receiving root-shaped screw-type dental implants placed from January 2000 to December 2009 was conducted. 6385 implants were placed in 3755 patients. The following data were collected from the dental records and radiographs: patient's age, gender, implant type and surface, length, diameter, location of implant placement, bone quality, prosthesis type. The correlations between these data and survival rate were analyzed. Statistical analysis was performed with the use of Kaplan-Meier analysis, Chi-square test and odds ratio. RESULTS In all, 6385 implants were placed in 3755 patients (3120 male, 635 female; mean age 65 ± 10.58 years). 108 implants failed and the cumulative survival rate was 96.33%. There were significant differences in age, implant type and surface, length, location and prosthesis type (P<.05). No significant differences were found in relation to the following factors: gender, diameter and bone quality (P>.05). CONCLUSION Related factors such as age, implant type, length, location and prosthesis type had a significant effect on the implant survival. PMID:22259704

  13. Proliferation rates of bovine primary muscle cells relate to liveweight and carcase weight in cattle.

    PubMed

    Coles, Chantal A; Wadeson, Jenny; Leyton, Carolina P; Siddell, Jason P; Greenwood, Paul L; White, Jason D; McDonagh, Matthew B

    2015-01-01

    Muscling in cattle is largely influenced by genetic background, ultimately affecting beef yield and is of major interest to the beef industry. This investigation aimed to determine whether primary skeletal muscle cells isolated from different breeds of cattle with a varying genetic potential for muscling differ in their myogenic proliferative capacity. Primary skeletal muscle cells were isolated and cultured from the Longissimus muscle (LM) of 6 month old Angus, Hereford and Wagyu X Angus cattle. Cells were assessed for rate of proliferation and gene expression of PAX7, MYOD, MYF5, and MYOG. Proliferation rates were found to differ between breeds of cattle whereby myoblasts from Angus cattle were found to proliferate at a greater rate than those of Hereford and Wagyu X Angus during early stages of growth (5-20 hours in culture) in vitro (P < 0.05). The proliferation rates of myoblasts during early stages of culture in vitro were also found to be positively related to the liveweight and carcase weight of cattle (P < 0.05). Gene expression of MYF5 was also found to be significantly down-regulated in WagyuX compared with Angus cattle (P < 0.05). These findings suggest that early events during myogenesis are important for determining liveweight and caracase weights in cattle. PMID:25875203

  14. Proliferation Rates of Bovine Primary Muscle Cells Relate to Liveweight and Carcase Weight in Cattle

    PubMed Central

    Coles, Chantal A.; Wadeson, Jenny; Leyton, Carolina P.; Siddell, Jason P.; Greenwood, Paul L.; White, Jason D.; McDonagh, Matthew B.

    2015-01-01

    Muscling in cattle is largely influenced by genetic background, ultimately affecting beef yield and is of major interest to the beef industry. This investigation aimed to determine whether primary skeletal muscle cells isolated from different breeds of cattle with a varying genetic potential for muscling differ in their myogenic proliferative capacity. Primary skeletal muscle cells were isolated and cultured from the Longissimus muscle (LM) of 6 month old Angus, Hereford and Wagyu X Angus cattle. Cells were assessed for rate of proliferation and gene expression of PAX7, MYOD, MYF5, and MYOG. Proliferation rates were found to differ between breeds of cattle whereby myoblasts from Angus cattle were found to proliferate at a greater rate than those of Hereford and Wagyu X Angus during early stages of growth (5–20 hours in culture) in vitro (P < 0.05). The proliferation rates of myoblasts during early stages of culture in vitro were also found to be positively related to the liveweight and carcase weight of cattle (P < 0.05). Gene expression of MYF5 was also found to be significantly down-regulated in WagyuX compared with Angus cattle (P < 0.05). These findings suggest that early events during myogenesis are important for determining liveweight and caracase weights in cattle. PMID:25875203

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

    PubMed Central

    Warren, Jeffrey J.; Mayer, James M.

    2010-01-01

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

  16. PREDICTIONS OF EVAPORATIVE LOSS RATES OF SOLUTES IN STAGNANT AND TURBENT WATERS IN RELATION TO RATES OF REFERENCE MATERIALS

    EPA Science Inventory

    A previously published kinetic model for evaporative rates of substances into air leads to the estimation of the dependence of solute transfer coefficients on turbulence applied to the system. The ratios of the transfer coefficients of all solutes become insensitive to air turbul...

  17. Sex Ratio at Birth and Mortality Rates Are Negatively Related in Humans

    PubMed Central

    Dama, Madhukar Shivajirao

    2011-01-01

    Evolutionary theory posits that resource availability and parental investment ability could signal offspring sex selection, in order to maximize reproductive returns. Non-human studies have provided evidence for this phenomenon, and maternal condition around the time of conception has been identified as most important factor that influence offspring sex selection. However, studies on humans have reported inconsistent results, mostly due to use of disparate measures as indicators of maternal condition. In the present study, the cross-cultural differences in human natal sex ratio were analyzed with respect to indirect measures of condition namely, life expectancy and mortality rate. Multiple regression modeling suggested that mortality rates have distinct predictive power independent of cross-cultural differences in fertility, wealth and latitude that were earlier shown to predict sex ratio at birth. These findings suggest that sex ratio variation in humans may relate to differences in parental and environmental conditions. PMID:21887320

  18. Sex ratio at birth and mortality rates are negatively related in humans.

    PubMed

    Dama, Madhukar Shivajirao

    2011-01-01

    Evolutionary theory posits that resource availability and parental investment ability could signal offspring sex selection, in order to maximize reproductive returns. Non-human studies have provided evidence for this phenomenon, and maternal condition around the time of conception has been identified as most important factor that influence offspring sex selection. However, studies on humans have reported inconsistent results, mostly due to use of disparate measures as indicators of maternal condition. In the present study, the cross-cultural differences in human natal sex ratio were analyzed with respect to indirect measures of condition namely, life expectancy and mortality rate. Multiple regression modeling suggested that mortality rates have distinct predictive power independent of cross-cultural differences in fertility, wealth and latitude that were earlier shown to predict sex ratio at birth. These findings suggest that sex ratio variation in humans may relate to differences in parental and environmental conditions. PMID:21887320

  19. Heart Rate during Conflicts Predicts Post-Conflict Stress-Related Behavior in Greylag Geese

    PubMed Central

    Wascher, Claudia A. F.; Fraser, Orlaith N.; Kotrschal, Kurt

    2010-01-01

    Background Social stressors are known to be among the most potent stressors in group-living animals. This is not only manifested in individual physiology (heart rate, glucocorticoids), but also in how individuals behave directly after a conflict. Certain ‘stress-related behaviors’ such as autopreening, body shaking, scratching and vigilance have been suggested to indicate an individual's emotional state. Such behaviors may also alleviate stress, but the behavioral context and physiological basis of those behaviors is still poorly understood. Methodology/Principal Findings We recorded beat-to-beat heart rates (HR) of 22 greylag geese in response to agonistic encounters using fully implanted sensor-transmitter packages. Additionally, for 143 major events we analyzed the behavior shown by our focal animals in the first two minutes after an interaction. Our results show that the HR during encounters and characteristics of the interaction predicted the frequency and duration of behaviors shown after a conflict. Conclusions/Significance To our knowledge this is the first study to quantify the physiological and behavioral responses to single agonistic encounters and to link this to post conflict behavior. Our results demonstrate that ‘stress-related behaviors’ are flexibly modulated by the characteristics of the preceding aggressive interaction and reflect the individual's emotional strain, which is linked to autonomic arousal. We found no support for the stress-alleviating hypothesis, but we propose that stress-related behaviors may play a role in communication with other group members, particularly with pair-partners. PMID:21187927

  20. Free energy of cluster formation and a new scaling relation for the nucleation rate

    SciTech Connect

    Tanaka, Kyoko K.; Tanaka, Hidekazu; Diemand, Jürg; Angélil, Raymond

    2014-05-21

    Recent very large molecular dynamics simulations of homogeneous nucleation with (1 − 8) × 10{sup 9} Lennard-Jones atoms [J. Diemand, R. Angélil, K. K. Tanaka, and H. Tanaka, J. Chem. Phys. 139, 074309 (2013)] allow us to accurately determine the formation free energy of clusters over a wide range of cluster sizes. This is now possible because such large simulations allow for very precise measurements of the cluster size distribution in the steady state nucleation regime. The peaks of the free energy curves give critical cluster sizes, which agree well with independent estimates based on the nucleation theorem. Using these results, we derive an analytical formula and a new scaling relation for nucleation rates: ln J{sup ′}/η is scaled by ln S/η, where the supersaturation ratio is S, η is the dimensionless surface energy, and J{sup ′} is a dimensionless nucleation rate. This relation can be derived using the free energy of cluster formation at equilibrium which corresponds to the surface energy required to form the vapor-liquid interface. At low temperatures (below the triple point), we find that the surface energy divided by that of the classical nucleation theory does not depend on temperature, which leads to the scaling relation and implies a constant, positive Tolman length equal to half of the mean inter-particle separation in the liquid phase.

  1. Dependence of the Firearm-Related Homicide Rate on Gun Availability: A Mathematical Analysis

    PubMed Central

    Wodarz, Dominik; Komarova, Natalia L.

    2013-01-01

    In the USA, the relationship between the legal availability of guns and the firearm-related homicide rate has been debated. It has been argued that unrestricted gun availability promotes the occurrence of firearm-induced homicides. It has also been pointed out that gun possession can protect potential victims when attacked. This paper provides a first mathematical analysis of this tradeoff, with the goal to steer the debate towards arguing about assumptions, statistics, and scientific methods. The model is based on a set of clearly defined assumptions, which are supported by available statistical data, and is formulated axiomatically such that results do not depend on arbitrary mathematical expressions. According to this framework, two alternative scenarios can minimize the gun-related homicide rate: a ban of private firearms possession, or a policy allowing the general population to carry guns. Importantly, the model identifies the crucial parameters that determine which policy minimizes the death rate, and thus serves as a guide for the design of future epidemiological studies. The parameters that need to be measured include the fraction of offenders that illegally possess a gun, the degree of protection provided by gun ownership, and the fraction of the population who take up their right to own a gun and carry it when attacked. Limited data available in the literature were used to demonstrate how the model can be parameterized, and this preliminary analysis suggests that a ban of private firearm possession, or possibly a partial reduction in gun availability, might lower the rate of firearm-induced homicides. This, however, should not be seen as a policy recommendation, due to the limited data available to inform and parameterize the model. However, the model clearly defines what needs to be measured, and provides a basis for a scientific discussion about assumptions and data. PMID:23923062

  2. Dependence of the firearm-related homicide rate on gun availability: a mathematical analysis.

    PubMed

    Wodarz, Dominik; Komarova, Natalia L

    2013-01-01

    In the USA, the relationship between the legal availability of guns and the firearm-related homicide rate has been debated. It has been argued that unrestricted gun availability promotes the occurrence of firearm-induced homicides. It has also been pointed out that gun possession can protect potential victims when attacked. This paper provides a first mathematical analysis of this tradeoff, with the goal to steer the debate towards arguing about assumptions, statistics, and scientific methods. The model is based on a set of clearly defined assumptions, which are supported by available statistical data, and is formulated axiomatically such that results do not depend on arbitrary mathematical expressions. According to this framework, two alternative scenarios can minimize the gun-related homicide rate: a ban of private firearms possession, or a policy allowing the general population to carry guns. Importantly, the model identifies the crucial parameters that determine which policy minimizes the death rate, and thus serves as a guide for the design of future epidemiological studies. The parameters that need to be measured include the fraction of offenders that illegally possess a gun, the degree of protection provided by gun ownership, and the fraction of the population who take up their right to own a gun and carry it when attacked. Limited data available in the literature were used to demonstrate how the model can be parameterized, and this preliminary analysis suggests that a ban of private firearm possession, or possibly a partial reduction in gun availability, might lower the rate of firearm-induced homicides. This, however, should not be seen as a policy recommendation, due to the limited data available to inform and parameterize the model. However, the model clearly defines what needs to be measured, and provides a basis for a scientific discussion about assumptions and data. PMID:23923062

  3. Heart Rate Variability and Sleep-Related Breathing Disorders in the General Population.

    PubMed

    Aeschbacher, Stefanie; Bossard, Matthias; Schoen, Tobias; Schmidlin, Delia; Muff, Christoph; Maseli, Anna; Leuppi, Jörg D; Miedinger, David; Probst-Hensch, Nicole M; Schmidt-Trucksäss, Arno; Risch, Martin; Risch, Lorenz; Conen, David

    2016-09-15

    Obstructive sleep apnea seems to have an important influence on the autonomic nervous system. In this study, we assessed the relations of sleep apnea-related parameters with 24-hour heart rate variability (HRV) in a large population of young and healthy adults. Participants aged 25 to 41 years with a body mass index <35 kg/m(2) and without known obstructive sleep apnea were included in a prospective population-based cohort study. HRV was assessed using 24-hour electrocardiographic monitoring. The SD of all normal RR intervals (SDNN) was used as the main HRV variable. Apnea-Hypopnea Index (AHI) and oxygen desaturation index (ODI) were obtained from nighttime pulse oximetry with nasal airflow measurements. We defined sleep-related breathing disorders as an AHI ≥5 or an ODI ≥5. Multivariable regression models were constructed to assess the relation of HRV with either AHI or ODI. Median age of the 1,255 participants was 37 years, 47% were men, and 9.6% had an AHI ≥5. Linear inverse associations of SDNN across AHI and ODI groups were found (p for trend = 0.006 and 0.0004, respectively). The β coefficients (95% CI) for the relation between SDNN and elevated AHI were -0.20 (-0.40 to -0.11), p = 0.04 and -0.29 (-0.47 to -0.11), p = 0.002 for elevated ODI. After adjustment for 24-hour heart rate, the same β coefficients (95% CI) were -0.06 (-0.22 to 0.11), p = 0.51 and -0.14 (-0.30 to 0.01), p = 0.07, respectively. In conclusion, even early stages of sleep-related breathing disorders are inversely associated with HRV in young and healthy adults, suggesting that they are tightly linked with autonomic dysfunction. However, HRV and 24-hour heart rate seem to have common information. PMID:27553103

  4. Relation of Total and Cardiovascular Death Rates to Climate System, Temperature, Barometric Pressure, and Respiratory Infection.

    PubMed

    Schwartz, Bryan G; Qualls, Clifford; Kloner, Robert A; Laskey, Warren K

    2015-10-15

    A distinct seasonal pattern in total and cardiovascular death rates has been reported. The factors contributing to this pattern have not been fully explored. Seven locations (average total population 71,354,000) were selected where data were available including relatively warm, cold, and moderate temperatures. Over the period 2004 to 2009, there were 2,526,123 all-cause deaths, 838,264 circulatory deaths, 255,273 coronary heart disease deaths, and 135,801 ST-elevation myocardial infarction (STEMI) deaths. We used time series and multivariate regression modeling to explore the association between death rates and climatic factors (temperature, dew point, precipitation, barometric pressure), influenza levels, air pollution levels, hours of daylight, and day of week. Average seasonal patterns for all-cause and cardiovascular deaths were very similar across the 7 locations despite differences in climate. After adjusting for multiple covariates and potential confounders, there was a 0.49% increase in all-cause death rate for every 1°C decrease. In general, all-cause, circulatory, coronary heart disease and STEMI death rates increased linearly with decreasing temperatures. The temperature effect varied by location, including temperature's linear slope, cubic fit, positional shift on the temperature axis, and the presence of circulatory death increases in locally hot temperatures. The variable effect of temperature by location suggests that people acclimatize to local temperature cycles. All-cause and circulatory death rates also demonstrated sizable associations with influenza levels, dew point temperature, and barometric pressure. A greater understanding of how climate, temperature, and barometric pressure influence cardiovascular responses would enhance our understanding of circulatory and STEMI deaths. PMID:26297511

  5. Growth Rate and Relocation Movements of Common Nighthawk (Chordeiles minor) Nestlings in Relation to Age

    USGS Publications Warehouse

    Kramer, Gunnar R.; Chalfoun, Anna D.

    2012-01-01

    Relocation by dependent young is a survival strategy that occurs among a wide range of taxa. The Common Nighthawk (Chordeiles minor) lays its eggs on bare substrate and, once hatched, nestlings may relocate to new sites daily. We located and monitored eight Common Nighthawk nests in Grand Teton National Park, Wyoming, quantified inter-use-site distances in relation to nestling age, and calculated a nestling growth rate curve. Common Nighthawk nestlings grow in a nearly linear fashion. Nestlings moved up to 48 m in a single day and larger, older nestlings tended to move greater distances between daily use-sites.

  6. An Examination of Sunspot Number Rates of Growth and Decay in Relation to the Sunspot Cycle

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2006-01-01

    On the basis of annual sunspot number averages, sunspot number rates of growth and decay are examined relative to both minimum and maximum amplitudes and the time of their occurrences using cycles 12 through present, the most reliably determined sunspot cycles. Indeed, strong correlations are found for predicting the minimum and maximum amplitudes and the time of their occurrences years in advance. As applied to predicting sunspot minimum for cycle 24, the next cycle, its minimum appears likely to occur in 2006, especially if it is a robust cycle similar in nature to cycles 17-23.

  7. Dynamical relations for left ventricular ejection - Flow rate, momentum, force and impulse

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Selzer, R. H.; Gordon, D. G.; Ledbetter, D. C.; Crawford, D. W.

    1984-01-01

    An investigation was carried out to quantitatively evaluate left ventricular volume flow rate, momentum, force and impulse derived from application of conservation principles for mass and momentum of blood within the ventricle during the ejection phase. An automated digital image processing system was developed and applied to left ventricular angiograms which are computer processed and analyzed frame by frame to determine the dynamical relations by numerical methods. The initial experience with force and impulse has indicated that neither quantity seemed to be a sensitive indicator of coronary artery disease as evaluated by qualitative angiography for the particular patient group studied. Utilization of the dynamical relations in evaluating human left ventricular performance requires improved means of measurement and interpretation of clinical studies.

  8. Flow Rate- and Fracture Property Dependence of Fracture-Matrix Ensemble Relative Permeability

    NASA Astrophysics Data System (ADS)

    Matthai, S. K.; Lang, P.; Bazrafkan, S.

    2012-12-01

    The grid-block scale ensemble relative permeability, kri of fractured porous rock with appreciable matrix permeability is of decisive interest to reservoir simulation and the prediction of production, injector-producer water breakthrough, and ultimate recovery. While the dynamic behaviour of naturally fractured reservoirs (NFR) already provides many clues about (pseudo) kri on the inter-well length scale, such data are difficult to interpret because, in the subsurface, the exact fracture geometry is unknown. Here we present numerical simulation results from discrete fracture and matrix (DFM) unstructured grid hybrid FEM-FVM simulation models, predicting the shape of fracture-matrix kri curves. In contrast to our earlier work, we also simulate capillary fracture matrix transfer (CFMT) and without relying the frequently made simplifying assumption that fracture saturation reflects fracture-matrix capillary pressure equilibrium. We also employ a novel discretization of saturation which permits jump discontinuities to develop across the fracture-matrix interface. This increased physical realism permits - for the first time - to test our earlier semi-analytical model of the flow rate dependence of relative permeability, ensuing from CFMT. The sensitivity analysis presented here constrains CMFT-related flow rate dependence of kri and illustrates how it manifests itself in two geometries of layer-restricted well-developed fracture patterns mapped in the field. We have also investigated the dependence of kri on fracture aperture as computed using discrete element analysis for plausible states of in situ stress. Our results indicate that fracture-matrix ensemble relative permeability can be matched with a new semi-analytic model taking into account the fracture-matrix flux ratio, the wetted fracture-matrix interface area as a function of saturation and the breakthrough saturation. However, we also detect a scale dependence of kri requiring a more elaborate treatment.

  9. Enclosure fire hazard analysis using relative energy release criteria. [burning rate and combustion control

    NASA Technical Reports Server (NTRS)

    Coulbert, C. D.

    1978-01-01

    A method for predicting the probable course of fire development in an enclosure is presented. This fire modeling approach uses a graphic plot of five fire development constraints, the relative energy release criteria (RERC), to bound the heat release rates in an enclosure as a function of time. The five RERC are flame spread rate, fuel surface area, ventilation, enclosure volume, and total fuel load. They may be calculated versus time based on the specified or empirical conditions describing the specific enclosure, the fuel type and load, and the ventilation. The calculation of these five criteria, using the common basis of energy release rates versus time, provides a unifying framework for the utilization of available experimental data from all phases of fire development. The plot of these criteria reveals the probable fire development envelope and indicates which fire constraint will be controlling during a criteria time period. Examples of RERC application to fire characterization and control and to hazard analysis are presented along with recommendations for the further development of the concept.

  10. Relative Rates of Surface and Volume Synthesis Set Bacterial Cell Size.

    PubMed

    Harris, Leigh K; Theriot, Julie A

    2016-06-01

    Many studies have focused on the mechanisms underlying length and width determination in rod-shaped bacteria. Here, we focus instead on cell surface area to volume ratio (SA/V) and demonstrate that SA/V homeostasis underlies size determination. We propose a model whereby the instantaneous rates of surface and volume synthesis both scale with volume. This model predicts that these relative rates dictate SA/V and that cells approach a new steady-state SA/V exponentially, with a decay constant equal to the volume growth rate. To test this, we exposed diverse bacterial species to sublethal concentrations of a cell wall biosynthesis inhibitor and observed dose-dependent decreases in SA/V. Furthermore, this decrease was exponential and had the expected decay constant. The model also quantitatively describes SA/V alterations induced by other chemical, nutritional, and genetic perturbations. We additionally present evidence for a surface material accumulation threshold underlying division, sensitizing cell length to changes in SA/V requirements. PMID:27259152

  11. Incidence rates of sickness absence related to mental disorders: a systematic literature review

    PubMed Central

    2014-01-01

    Background Over the past decade, growing attention has been given to the mental health of workers. One way to examine the mental health of workers is to look at the incidence rates of mental illness-related sickness absence. There is a scarcity of literature in which the incidence rates of mental illness-related sickness absence among different countries have been considered together. The purpose of this systematic literature review is to address the question: Are there similarities and differences in the incidence rates of mental disorder-related sickness absence among and within OECD identified Social Democratic, Liberal and Latin American country categories? In this paper, we seek to identify differences and similarities in the literature rather than to explain them. With this review, we lay the groundwork for and point to areas for future research as well as to raise questions regarding reasons for the differences and similarities. Methods A systematic literature search of the following databases were performed: Medline Current, Medline In-process, PsycINFO, Econlit and Web of Science. The search period covered 2002–2013. The systematic literature search focused on working adults between 18–65 years old who had not retired and who had mental and/or substance abuse disorders. Intervention studies were excluded. The search focused on medically certified sickness absences. Results A total of 3,818 unique citations were identified. Of these, 10 studies met the inclusion/exclusion criteria; six were from Social Democratic countries. Their quality ranged from good to excellent. There was variation in the incidence rates reported by the studies from the Social Democratic, Liberal and Latin American countries in this review. Conclusions The results of this systematic review suggest that this is an emerging area of inquiry that needs to continue to grow. Priority areas to support growth include cross jurisdictional collaboration and development of a typology

  12. Defensive Traits in Young Pine Trees Cluster into Two Divergent Syndromes Related to Early Growth Rate

    PubMed Central

    Moreira, Xoaquín; Sampedro, Luis; Zas, Rafael; Pearse, Ian S.

    2016-01-01

    The combination of defensive traits leads to the evolution of ‘plant defense syndromes’ which should provide better protection against herbivores than individual traits on their own. Defense syndromes can be generally driven by plant phylogeny and/or biotic and abiotic factors. However, we lack a solid understanding of (i) the relative importance of shared evolution vs. convergence due to similar ecological conditions and (ii) the role of induced defense strategies in shaping defense syndromes. We investigate the relative roles of evolutionary and ecological factors shaping the deployment of pine defense syndromes including multiple constitutive and induced chemical defense traits. We performed a greenhouse experiment with seedlings of eighteen species of Pinaceae family, and measured plant growth rate, constitutive chemical defenses and their inducibility. Plant growth rate, but not phylogenetic relatedness, determined the deployment of two divergent syndromes. Slow-growing pine species living in harsh environments where tissue replacement is costly allocated more to constitutive defenses (energetically more costly to produce than induced). In contrast, fast-growing species living in resource-rich habitats had greater inducibility of their defenses, consistent with the theory of constitutive-induced defense trade-offs. This study contributes to a better understanding of evolutionary and ecological factors driving the deployment of defense syndromes. PMID:27028433

  13. Sulfate Reduction Relative to Methane Production in High-Rate Anaerobic Digestion: Technical Aspects

    PubMed Central

    Isa, Zaid; Grusenmeyer, Stéphane; Verstraete, Willy

    1986-01-01

    The effect of different substrates and different levels of sulfate and sulfide on methane production relative to sulfate reduction in high-rate anaerobic digestion was evaluated. Reactors could be acclimated so that sulfate up to a concentration of 5 g of sulfate S per liter did not significantly affect methanogenesis. Higher levels gave inhibition because of salt toxicity. Sulfate reduction was optimal at a relatively low level of sulfate, i.e., 0.5 g of sulfate S per liter, but was also not significantly affected by higher levels. Both acetoclastic and hydrogenotrophic methane-producing bacteria adapted to much higher levels of free H2S than the values reported in the literature (50% inhibition occurred only at free H2S levels of more than 1,000 mg/liter). High levels of free H2S affected the sulfate-reducing bacteria only slightly. Formate and acetate supported the sulfate-reducing bacteria very poorly. In the high-rate reactors studied, intensive H2S formation occurred only when H2 gas or an H2 precursor such as ethanol was supplied. PMID:16347018

  14. Defensive Traits in Young Pine Trees Cluster into Two Divergent Syndromes Related to Early Growth Rate.

    PubMed

    Moreira, Xoaquín; Sampedro, Luis; Zas, Rafael; Pearse, Ian S

    2016-01-01

    The combination of defensive traits leads to the evolution of 'plant defense syndromes' which should provide better protection against herbivores than individual traits on their own. Defense syndromes can be generally driven by plant phylogeny and/or biotic and abiotic factors. However, we lack a solid understanding of (i) the relative importance of shared evolution vs. convergence due to similar ecological conditions and (ii) the role of induced defense strategies in shaping defense syndromes. We investigate the relative roles of evolutionary and ecological factors shaping the deployment of pine defense syndromes including multiple constitutive and induced chemical defense traits. We performed a greenhouse experiment with seedlings of eighteen species of Pinaceae family, and measured plant growth rate, constitutive chemical defenses and their inducibility. Plant growth rate, but not phylogenetic relatedness, determined the deployment of two divergent syndromes. Slow-growing pine species living in harsh environments where tissue replacement is costly allocated more to constitutive defenses (energetically more costly to produce than induced). In contrast, fast-growing species living in resource-rich habitats had greater inducibility of their defenses, consistent with the theory of constitutive-induced defense trade-offs. This study contributes to a better understanding of evolutionary and ecological factors driving the deployment of defense syndromes. PMID:27028433

  15. On the Reversal of Star formation Rate-Density Relation at z = 1: Insights from Simulations

    NASA Astrophysics Data System (ADS)

    Tonnesen, Stephanie; Cen, Renyue

    2014-06-01

    Recent surveys have found a reversal of the star formation rate (SFR)-density relation at z = 1 from that at z = 0, while the sign of the slope of the color-density relation remains unchanged. We use adaptive mesh refinement cosmological hydrodynamic simulations of a 21 × 24 × 20 h -3 Mpc3 region to examine the SFR-density and color-density relations of galaxies at z = 0 and z = 1. The local environmental density is defined by the dark matter mass in spheres of radius 1 h -1 Mpc, and we probe two decades of environmental densities. Our simulations produce a large increase of SFR with density at z = 1, as in the Elbaz et al. observations. We also find a significant evolution to z = 0, where the SFR-density relation is much flatter. The simulated color-density relation is consistent from z = 1 to z = 0, in agreement with observations. We find that the increase in SFR with local density at z = 1 is due to a growing population of star-forming galaxies in higher-density environments. At z = 0 and z = 1 both the SFR and cold gas mass are correlated with the galaxy halo mass, and therefore the correlation between median halo mass and local density is an important cause of the SFR-density relation at both redshifts. However, at z = 0 the local density on 1 h -1 Mpc scales affects galaxy SFRs as much as halo mass. Finally, we find indications that while at z = 0 high-density environments depress galaxy SFRs, at z = 1 high-density environments tend to increase SFRs.

  16. On the reversal of star formation rate-density relation at z = 1: Insights from simulations

    SciTech Connect

    Tonnesen, Stephanie; Cen, Renyue E-mail: cen@astro.princeton.edu

    2014-06-20

    Recent surveys have found a reversal of the star formation rate (SFR)-density relation at z = 1 from that at z = 0, while the sign of the slope of the color-density relation remains unchanged. We use adaptive mesh refinement cosmological hydrodynamic simulations of a 21 × 24 × 20 h {sup –3} Mpc{sup 3} region to examine the SFR-density and color-density relations of galaxies at z = 0 and z = 1. The local environmental density is defined by the dark matter mass in spheres of radius 1 h {sup –1} Mpc, and we probe two decades of environmental densities. Our simulations produce a large increase of SFR with density at z = 1, as in the Elbaz et al. observations. We also find a significant evolution to z = 0, where the SFR-density relation is much flatter. The simulated color-density relation is consistent from z = 1 to z = 0, in agreement with observations. We find that the increase in SFR with local density at z = 1 is due to a growing population of star-forming galaxies in higher-density environments. At z = 0 and z = 1 both the SFR and cold gas mass are correlated with the galaxy halo mass, and therefore the correlation between median halo mass and local density is an important cause of the SFR-density relation at both redshifts. However, at z = 0 the local density on 1 h {sup –1} Mpc scales affects galaxy SFRs as much as halo mass. Finally, we find indications that while at z = 0 high-density environments depress galaxy SFRs, at z = 1 high-density environments tend to increase SFRs.

  17. Erythrocyte storage increases rates of NO- and Nitrite scavenging: Implications for transfusion related toxicity

    PubMed Central

    Stapley, Ryan; Owusu, Benjamin Y.; Brandon, Angela; Cusick, Marianne; Rodriguez, Cilina; Marques, Marisa B.; Kerby, Jeffrey D.; Barnum, Scott R.; Weinberg, Jordan A.; Lancaster, Jack R.; Patel, Rakesh P.

    2013-01-01

    Synopsis Storage of erythrocytes in blood banks is associated with biochemical and morphological changes to the RBC. It has been suggested that these changes have a potential negative clinical effects characterized by inflammation and microcirculatory dysfunction which add to other transfusion related toxicities. However, mechanisms linking RBC storage and toxicity remain unclear. In this study we tested the hypothesis that storage of leukodepleted RBC result in cells that inhibit nitric oxide (NO)-signaling more so than younger cells. Using competition kinetic analyses and protocols that minimized contributions from hemolysis or microparticles, our data indicate that NO-consumption rates increased ~40-fold and NO-dependent vasodilation was inhibited 2-4 fold with 42d old vs. 0d RBC. These results are likely due to the formation of smaller RBC with increased surface area: volume as a consequence of membrane loss during storage. The potential for older RBC to affect NO-formation via deoxygenated RBC mediated nitrite reduction was also tested. RBC storage did not affect deoxygenated RBC-dependent stimulation of nitrite-induced vasodilation. However, stored RBC did increase the rates of nitrite oxidation to nitrate in vitro. Significant loss of whole blood nitrite was also observed in stable trauma patients after transfusion with 1 RBC unit, with the decrease in nitrite occurring after transfusion with RBC stored for >25d, but not with younger RBC. Collectively, these data suggest that increased rates of reactions between intact RBC and NO and nitrite may contribute to mechanisms that lead to storage lesion-related transfusion risk PMID:22720637

  18. Erythrocyte storage increases rates of NO and nitrite scavenging: implications for transfusion-related toxicity.

    PubMed

    Stapley, Ryan; Owusu, Benjamin Y; Brandon, Angela; Cusick, Marianne; Rodriguez, Cilina; Marques, Marisa B; Kerby, Jeffrey D; Barnum, Scott R; Weinberg, Jordan A; Lancaster, Jack R; Patel, Rakesh P

    2012-09-15

    Storage of erythrocytes in blood banks is associated with biochemical and morphological changes to RBCs (red blood cells). It has been suggested that these changes have potential negative clinical effects characterized by inflammation and microcirculatory dysfunction which add to other transfusion-related toxicities. However, the mechanisms linking RBC storage and toxicity remain unclear. In the present study we tested the hypothesis that storage of leucodepleted RBCs results in cells that inhibit NO (nitric oxide) signalling more so than younger cells. Using competition kinetic analyses and protocols that minimized contributions from haemolysis or microparticles, our data indicate that the consumption rates of NO increased ~40-fold and NO-dependent vasodilation was inhibited 2-4-fold comparing 42-day-old with 0-day-old RBCs. These results are probably due to the formation of smaller RBCs with increased surface area: volume as a consequence of membrane loss during storage. The potential for older RBCs to affect NO formation via deoxygenated RBC-mediated nitrite reduction was also tested. RBC storage did not affect deoxygenated RBC-dependent stimulation of nitrite-induced vasodilation. However, stored RBCs did increase the rates of nitrite oxidation to nitrate in vitro. Significant loss of whole-blood nitrite was also observed in stable trauma patients after transfusion with 1 RBC unit, with the decrease in nitrite occurring after transfusion with RBCs stored for >25 days, but not with younger RBCs. Collectively, these data suggest that increased rates of reactions between intact RBCs and NO and nitrite may contribute to mechanisms that lead to storage-lesion-related transfusion risk. PMID:22720637

  19. Population-Based Age Group Specific Annual Incidence Rates of Symptomatic Age-Related Macular Degeneration

    PubMed Central

    Saari, Jukka M

    2014-01-01

    Purpose To study the population-based annual incidence rates of exudative, dry and all cases of symptomatic age-related macular degeneration (AMD) in different age and sex groups. Methods. This is a one year, prospective, population-based study on all consecutive new patients with AMD in the hospital district of Central Finland. The diagnosis was confirmed in all patients with slit lamp biomicroscopy, optical coherence tomography (OCT) using a Spectralis HRA + OCT device, and the Heidelberg Eye Explorer 1.6.2.0 program. Fluorescein angiograms were taken when needed. Results. The population-based annual incidence rates of all cases of symptomatic AMD increased from 0.03% (95% CI, 0.01-0.05%) in the age group 50-59 years to 0.82% (95% CI, 0.55-1.09%) in the age group 85-89 years and were 0.2% (95% CI, 0.17-0.24%) in exudative, 0.11% (95% CI, 0.09-0.14%) in dry, and 0.32% (95% CI, 0.28-0.36%) in all cases of AMD in the age group 60 years and older. During the next 20 years in Central Finland the population-based annual incidence rates can be estimated to increase to 0.27% (95% CI, 0.24-0.30%) in exudative, to 0.13% (95% CI, 0.11-0.15%) in dry, and to 0.41% (95% CI, 0.37-0.45%) in all cases of AMD in the age group 60 years and older. The population-based annual incidence of AMD did not show statistically significant differences between males and females (p>0.1). Conclusion: The population-based age-group specific annual incidence rates of symptomatic AMD of this study may help to plan health care provision for patients of AMD. PMID:25674187

  20. Relating Spontaneously Reported Extrapyramidal Adverse Events to Movement Disorder Rating Scales

    PubMed Central

    Karayal, Onur N.; Kolluri, Sheela; Vanderburg, Douglas; Kemmler, Georg; Fleischhacker, W. Wolfgang

    2015-01-01

    Background: While antipsychotic-induced extrapyramidal symptoms (EPS) and akathisia remain important concerns in the treatment of patients with schizophrenia, the relationship between movement disorder rating scales and spontaneously reported EPS-related adverse events (EPS-AEs) remains unexplored. Methods: Data from four randomized, placebo- and haloperidol-controlled ziprasidone trials were analyzed to examine the relationship between spontaneously reported EPS-AEs with the Simpson Angus Scale (SAS) and Barnes Akathisia Rating Scale (BARS). Categorical summaries were created for each treatment group to show the frequencies of subjects with EPS-AEs in each of the SAS and BARS categories at weeks 1, 3, and 6, and agreement between ratings was quantified by means of weighted kappa (κ). Results: In general, we found greater frequencies of EPS-AEs with increasing severity of the SAS and BARS scores. The EPS-AEs reported with a “none” SAS score ranged from 0 to 22.2%, with a “mild” SAS score from 3.3 to 29.0%, and with a “moderate” SAS score from 0 to 100%. No subjects in any treatment group reported “severe” SAS scores or corresponding EPS-AEs. Agreement between SAS scores and EPS-AEs was poor for ziprasidone and placebo (κ < 0.2) and only slightly better for haloperidol. The EPS-AEs reported with “non questionable” BARS scores ranged from 1.9 to 9.8%, with “mild moderate” BARS scores from 12.8 to 54.6%, and with “marked severe” scores from 0 to 100%. Agreement was modest for ziprasidone and placebo (κ < 0.4) and moderate for haloperidol (κ < 0.6). Conclusions: These findings may reflect either underreporting of AEs by investigators and subjects or erroneous rating scale evaluations. PMID:26116494

  1. Controlling the relative rates of adlayer formation and removal during etching in inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Fuller, Nicholas Colvin Masi

    Laser desorption (LD) of the adlayer coupled with laser induced fluorescence (LIF) and plasma induced emission (PIE) of desorbed adsorbates is used to investigate the relative rates of chlorination and sputtering during the etching of Si in inductively coupled Cl2-Ar plasmas. Such an analysis is a two-fold process: surface analysis and plasma characterization. Surface analysis of Si etching using LD-LIF and LD-PIE techniques combined with etch rate measurements have revealed that the coverage of SiCl2 and etch rate increases and coverage of Si decreases abruptly for a chlorine fraction of 75% and ion energy of 80 eV. The precise Cl2 fraction for which these abrupt changes occur increases with an increase in ion energy. These changes may be caused by local chemisorption-induced reconstruction of Si <100>. Furthermore, the chlorination and sputtering rates are increased by ˜ an order of magnitude as the plasma is changed from Ar-dominant to Cl-dominant. Characterization of the plasma included determination of the dominant ion in Cl2 plasmas using LIF and a Langmuir probe and measurement of the absolute densities of Cl2, Cl, Cl+, and At + in Cl2-Ar discharges using optical emission actinometry. These studies reveal that Cl+ is the dominant positive ion in the H-mode and the dissociation of Cl2 to Cl increases with an increase in Ar fraction due to an increase in electron temperature. Furthermore, for powers exceeding 600 W, the neutral to ion flux ratio is strongly dependent on Cl2 fraction and is attributed mostly to the decrease in Cl density. Such dependence of the flux ratio on Cl2 fraction is significant in controlling chlorination and sputtering rates not only for Si etching, but for etching other key technological materials. ICP O2 discharges were also studied for low-kappa polymeric etch applications. These studies reveal that the electron temperature is weakly dependent on rf power and O2 dissociation is low (˜2%) at the maximum rf power density of 5.7 Wcm

  2. Turnover rate of cerebrospinal fluid in female sheep: changes related to different light-dark cycles

    PubMed Central

    Thiéry, Jean-Claude; Lomet, Didier; Bougoin, Sylvain; Malpaux, Benoit

    2009-01-01

    Background Sheep are seasonal breeders. The key factor governing seasonal changes in the reproductive activity of the ewe is increased negative feedback of estradiol at the level of the hypothalamus under long-day conditions. It has previously been demonstrated that when gonadotropin secretions are inhibited during long days, there is a higher concentration of estradiol in the cerebrospinal fluid (CSF) than during short days. This suggests an involvement of the CSF and choroid plexus in the neuroendocrine regulatory loop, but the mechanisms underlying this phenomenon remain unknown. One possible explanation of this difference in hormonal content is an effect of concentration or dilution caused by variations in CSF secretion rate. The aim of this study was thus to investigate changes in the CSF turnover rate related to light-dark cycles. Methods The turnover rate of the CSF was estimated by measuring the time taken for the recovery of intraventricular pressure (IVP) after removal of a moderate volume (0.5 to 2 ml) of CSF (slope in mmHg/min). The turnover rate was estimated three times in the same group of sheep: during a natural period of decreasing day-length corresponding to the initial period when gonadotropin activity is stimulated (SG1), during a long-day inhibitory period (IG), and finally during a short-day stimulatory period (SG2). Results The time taken and the speed of recovery of initial IVP differed between groups: 8 min 30 sec, 0.63 ± 0.07 mmHg/min(SG1), 11 min 1 sec, 0.38 ± 0.06 mmHg/min (IG) and 9 min 0 sec, 0.72 ± 0.15 mmHg/min (SG2). Time changes of IVP differed between groups (ANOVA, p < 0.005, SG1 different from IG, p < 0.05). The turnover rate in SG2: 183.16 ± 23.82 μl/min was not significantly different from SG1: 169. 23 ± 51.58 μl/min (Mann-Whitney test, p = 0.41), but was significantly different from IG: 71.33 ± 16.59 μl/min (p = 0.016). Conclusion This study shows that the turnover rate of CSF in ewes changes according to the light

  3. 77 FR 73456 - Update to the TR-12 Fuel Related Rate Adjustment Policy (SDDC Fuel Surcharge Policy)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-10

    ... Department of the Army Update to the TR-12 Fuel Related Rate Adjustment Policy (SDDC Fuel Surcharge Policy...: Reference: TR-12 Fuel Related Rate Adjustment Policy. Background: The following FRA policy applies to... increases in diesel fuel prices. Miscellaneous: A copy of the TR-12 FRA Policy can be accessed via the...

  4. Body surface related flow rate nomograms in a normal pediatric population.

    PubMed

    Wese, F X; Gaum, L D; Liu, T P; Wong, A K; Hardy, B E; Churchill, B M

    1989-01-01

    Uroflow studies for 511 normal pediatric subjects (272 boys, 239 girls) were analyzed statistically. Nomograms relating peak flow to volume voided and body surface were established. An acceptable lower limit for peak flow was obtained from the data and a volume voided range was calculated so that both criteria could be used with 90% probability to define the normal voiding situation. Body surface area was found to be a more reliable index than age in the establishment of nomograms. In the male population the 90% probability applied to a significantly greater volume voided reliability. In the female population mean peak flow rate rose with increased body surface. Finally, in both sexes the 10% lower limit was closer to the regression mean, allowing a tighter distribution around this value. PMID:2763926

  5. Relative rate constants for the reactions of atomic oxygen with HO2 anad OH radicals

    NASA Technical Reports Server (NTRS)

    Keyser, L. F.

    1983-01-01

    Relative rate constants for the reactions O + HO2 - OH + O2 (1) and O + OH - H + O2 (2) were obtained by using the discharge-flow resonance fluorescence technique at 2 torr total pressure and 299 K. HO2 radicals were generated by reacting atomic hydrogen with an excess of O2. Quasi-steady-state concentrations of OH and HO2 were established in the presence of excess atomic oxygen. Observed concentration ratios, namely the ratio of the OH concentration to the HO2 concentration, resulted in a value of 1.7 + or 0.2 for k1/k2. The error limits are twice the standard deviation obtained from the data analysis. Overall experimental error is estimated to be + or - 25 percent. This result confirms earlier direct measurements of k1 and k2 which required knowledge of absolute radical or atomic oxygen concentrations.

  6. Tide-related biological rhythm in the oxygen consumption rate of ghost shrimp (Neotrypaea uncinata).

    PubMed

    Leiva, Félix P; Niklitschek, Edwin J; Paschke, Kurt; Gebauer, Paulina; Urbina, Mauricio A

    2016-07-01

    The effects of tidal height (high and low), acclimation to laboratory conditions (days in captivity) and oxygen level (hypoxia and normoxia) were evaluated in the oxygen consumption rate (OCR) of the ghost shrimp Neotrypaea uncinata We evaluated the hypothesis that N. uncinata reduces its OCR during low tide and increases it during high tide, regardless of oxygen level or acclimation. Additionally, the existence of an endogenous rhythm in OCR was explored, and we examined whether it synchronized with tidal, diurnal or semidiurnal cycles. Unexpectedly, high OCRs were observed at low tide, during normoxia, in non-acclimated animals. Results from a second, longer experiment under normoxic conditions suggested the presence of a tide-related metabolic rhythm, a response pattern not yet demonstrated for a burrowing decapod. Although rhythms persisted for only 2 days after capture, their period of 12.8 h closely matched the semidiurnal tidal cycle that ghost shrimp confront inside their burrows. PMID:27099365

  7. Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers

    NASA Technical Reports Server (NTRS)

    Anderson, I. C.; Levine, J. S.

    1986-01-01

    An account is given of the atmospheric chemical and photochemical effects of biogenic nitric and nitrous oxide emissions. The magnitude of the biogenic emission of NO is noted to remain uncertain. Possible soil sources of NO and N2O encompass nitrification by autotropic and heterotropic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. Oxygen availability is the primary determinant of these organisms' relative rates of activity. The characteristics of this major influence are presently investigated in light of the effect of oxygen partial pressure on NO and N2O production by a wide variety of common soil-nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The results obtained indicate that aerobic soils are primary sources only when there is sufficient moisture to furnish anaerobic microsites for denitrification.

  8. Relative rate and location of intra-host HIV evolution to evade cellular immunity are predictable.

    PubMed

    Barton, John P; Goonetilleke, Nilu; Butler, Thomas C; Walker, Bruce D; McMichael, Andrew J; Chakraborty, Arup K

    2016-01-01

    Human immunodeficiency virus (HIV) evolves within infected persons to escape being destroyed by the host immune system, thereby preventing effective immune control of infection. Here, we combine methods from evolutionary dynamics and statistical physics to simulate in vivo HIV sequence evolution, predicting the relative rate of escape and the location of escape mutations in response to T-cell-mediated immune pressure in a cohort of 17 persons with acute HIV infection. Predicted and clinically observed times to escape immune responses agree well, and we show that the mutational pathways to escape depend on the viral sequence background due to epistatic interactions. The ability to predict escape pathways and the duration over which control is maintained by specific immune responses open the door to rational design of immunotherapeutic strategies that might enable long-term control of HIV infection. Our approach enables intra-host evolution of a human pathogen to be predicted in a probabilistic framework. PMID:27212475

  9. Vertex evoked potentials in a rating-scale detection task: Relation to signal probability

    NASA Technical Reports Server (NTRS)

    Squires, K. C.; Squires, N. K.; Hillyard, S. A.

    1974-01-01

    Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal.

  10. Relative rate and location of intra-host HIV evolution to evade cellular immunity are predictable

    PubMed Central

    Barton, John P.; Goonetilleke, Nilu; Butler, Thomas C.; Walker, Bruce D.; McMichael, Andrew J.; Chakraborty, Arup K.

    2016-01-01

    Human immunodeficiency virus (HIV) evolves within infected persons to escape being destroyed by the host immune system, thereby preventing effective immune control of infection. Here, we combine methods from evolutionary dynamics and statistical physics to simulate in vivo HIV sequence evolution, predicting the relative rate of escape and the location of escape mutations in response to T-cell-mediated immune pressure in a cohort of 17 persons with acute HIV infection. Predicted and clinically observed times to escape immune responses agree well, and we show that the mutational pathways to escape depend on the viral sequence background due to epistatic interactions. The ability to predict escape pathways and the duration over which control is maintained by specific immune responses open the door to rational design of immunotherapeutic strategies that might enable long-term control of HIV infection. Our approach enables intra-host evolution of a human pathogen to be predicted in a probabilistic framework. PMID:27212475

  11. Calibrating the Decline Rate - Peak Luminosity Relation for Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Rust, Bert W.; Pruzhinskaya, Maria V.; Thijsse, Barend J.

    2015-08-01

    The correlation between peak luminosity and rate of decline in luminosity for Type I supernovae was first studied by B. W. Rust [Ph.D. thesis, Univ. of Illinois (1974) ORNL-4953] and Yu. P. Pskovskii [Sov. Astron., 21 (1977) 675] in the 1970s. Their work was little-noted until Phillips rediscovered the correlation in 1993 [ApJ, 413 (1993) L105] and attempted to derive a calibration relation using a difference quotient approximation Δm15(B) to the decline rate after peak luminosity Mmax(B). Numerical differentiation of data containing measuring errors is a notoriously unstable calculation, but Δm15(B) remains the parameter of choice for most calibration methods developed since 1993. To succeed, it should be computed from good functional fits to the lightcurves, but most workers never exhibit their fits. In the few instances where they have, the fits are not very good. Some of the 9 supernovae in the Phillips study required extinction corrections in their estimates of the Mmax(B), and so were not appropriate for establishing a calibration relation. Although the relative uncertainties in his Δm15(B) estimates were comparable to those in his Mmax(B) estimates, he nevertheless used simple linear regression of the latter on the former, rather than major-axis regression (total least squares) which would have been more appropriate.Here we determine some new calibration relations using a sample of nearby "pure" supernovae suggested by M. V. Pruzhinskaya [Astron. Lett., 37 (2011) 663]. Their parent galaxies are all in the NED collection, with good distance estimates obtained by several different methods. We fit each lightcurve with an optimal regression spline obtained by B. J. Thijsse's spline2 [Comp. in Sci. & Eng., 10 (2008) 49]. The fits, which explain more that 99% of the variance in each case, are better than anything heretofore obtained by stretching "template" lightcurves or fitting combinations of standard lightcurves. We use the fits to compute estimates of

  12. HIV in the Leather Community: Rates and Risk-Related Behaviors

    PubMed Central

    Moskowitz, David A.; Seal, David W.; Rintamaki, Lance; Rieger, Gerulf

    2014-01-01

    There exist many subcultures of men who have sex with men (MSM), all with differing values and health behaviors. The Leathermen comprise one such subculture, which is characterized by a heightened valuation of hypersexuality and adherence to sexual control dynamics (i.e., submission and dominance). No previous research has specifically examined this community for differences in sexual health (e.g., HIV rates) and sexual health behaviors (e.g., condom use). We conducted a large survey of men (N = 1,554) at one leather and non-leather event, collecting data from 655 Submissives, Dominants, Switches, and non-orienting Leathermen. Leathermen were 61% more likely to be HIV-positive than non-Leathermen. Decreased condom use found in HIV-positive Leathermen (relative to HIV-positive non-Leathermen) was a potential factor contributing to heightened HIV rates. Universal low condom use in Submissives engaging in receptive, and Dominants engaging in insertive, anal intercourse was an additional trend that potentially contributed to increased numbers of HIV-positive Leathermen. Our recommendation is for heightened awareness of the risks associated with sex among Leathermen, especially unprotected anal intercourse with sero-uncertain Submissives. PMID:19904599

  13. Does seed mass drive the differences in relative growth rate between growth forms?

    PubMed

    Houghton, Jennie; Thompson, Ken; Rees, Mark

    2013-07-01

    The idea that herbaceous plants have higher relative growth rates (RGRs) compared with woody plants is fundamental to many of the most influential theories in plant ecology. This difference in growth rate is thought to reflect systematic variation in physiology, allocation and leaf construction. Previous studies documenting this effect have, however, ignored differences in seed mass. As woody species often have larger seeds and RGR is negatively correlated with seed mass, it is entirely possible the lower RGRs observed in woody species is a consequence of having larger seeds rather than different growth strategies. Using a synthesis of the published literature, we explored the relationship between RGR and growth form, accounting for the effects of seed mass and study-specific effects (e.g. duration of study and pot volume), using a mixed-effects model. The model showed that herbaceous species do indeed have higher RGRs than woody species, and that the difference was independent of seed mass, thus at all seed masses, herbaceous species on average grow faster than woody ones. PMID:23677351

  14. Varying relative degradation rates of oil in different forms and environments revealed by ramped pyrolysis.

    PubMed

    Pendergraft, Matthew A; Rosenheim, Brad E

    2014-09-16

    Degradation of oil contamination yields stabilized products by removing and transforming reactive and volatile compounds. In contaminated coastal environments, the processes of degradation are influenced by shoreline energy, which increases the surface area of the oil as well as exchange between oil, water, sediments, microbes, oxygen, and nutrients. Here, a ramped pyrolysis carbon isotope technique is employed to investigate thermochemical and isotopic changes in organic material from coastal environments contaminated with oil from the 2010 BP Deepwater Horizon oil spill. Oiled beach sediment, tar ball, and marsh samples were collected from a barrier island and a brackish marsh in southeast Louisiana over a period of 881 days. Stable carbon ((13)C) and radiocarbon ((14)C) isotopic data demonstrate a predominance of oil-derived carbon in the organic material. Ramped pyrolysis profiles indicate that the organic material was transformed into more stable forms. Our data indicate relative rates of stabilization in the following order, from fastest to slowest: high energy beach sediments > low energy beach sediments > marsh > tar balls. Oil was transformed most rapidly where shoreline energy and the rates of oil dispersion and exchange with water, sediments, microbes, oxygen, and nutrients were greatest. Still, isotope data reveal persistence of oil. PMID:25105342

  15. Low heart rate variability and cancer-related fatigue in breast cancer survivors

    PubMed Central

    Crosswell, Alexandra D.; Lockwood, Kimberly G.; Ganz, Patricia A.; Bower, Julienne E.

    2015-01-01

    Cancer-related fatigue is a common and often long lasting symptom for many breast cancer survivors. Fatigued survivors show evidence of elevated inflammation, but the physiological mechanisms driving inflammatory activity have not been determined. Alterations in the autonomic nervous system, and particularly parasympathetic nervous system activity, are a plausible, yet understudied contributor to cancer-related fatigue. The goal of this study was to replicate one previous study showing an association between lower parasympathetic activity and higher fatigue in breast cancer survivors (Fagundes et al., 2011), and to examine whether inflammation mediates this association. Study participants were drawn from two samples and included 84 women originally diagnosed with early-stage breast cancer prior to age 50. Participants completed questionnaires, provided blood samples for determination of interleukin (IL)-6 and C-reactive protein (CRP), and underwent electrocardiography (ECG) assessment for evaluation of resting heart rate variability (HRV), a measure of parasympathetic activity. Results showed that lower HRV was associated with higher fatigue (p < .05), as predicted. In bivariate analyses, HRV was also correlated with circulating concentrations of IL-6 and CRP. However, path analyses did not support inflammation as a mediator of the association between HRV and fatigue; instead, associations among these variables appeared to be driven by age and BMI. These findings identify HRV as a potential contributor to cancer-related fatigue, but suggest that inflammation does not mediate this association in younger, healthy breast cancer survivors who are several years post-treatment. The autonomic nervous system merits additional attention in research on the etiology of cancer-related fatigue. PMID:24845177

  16. Sex-specific age-related changes of information processing rate indicators during childhood and adolescence.

    PubMed

    Zebec, Mislav S; Budimir, Sanja; Merkas, Marina; Szirovicza, Lajos; Zivicnjak, Miroslav

    2014-06-01

    Despite the relevant findings on non-average information processing rate (IPR) indicators-intelligence relation, and on age-related changes of some of these indicators during aging, the research on sex-specific age-related changes of these indicators during childhood and adolescence are lacking. In a transversal study, 1197 school children (598 girls) aged 8-18 have been individually measured on 5 IPR indicators--two averages (mean_t, median_t) and three non-averages (min_t, max_t, sd_t). The results corroborated the expected non-linear changes of average IPR indicators in the observed developmental period, whereby the sex difference in related developmental patterns was detected: marked age-related decrement in girls ceased at the age of 12, and in boys around the age of 13-14, after which progress in both sexes gradually ceased by the age of 18 and was less pronounced in girls. Generally similar non-linear age-related decrements of non-average indicators were registered, but they showed mutual intensity differences at specific ages and sex difference in developmental patterns was detected, analogously to average indicators. Systematic sex differences in the whole observed period were obtained only in two non-average indicators: girls showed minor sd_t and boys showed minor min_t. In specific age groups, a number of sex differences were obtained that are explainable by two possible mechanisms: earlier maturation in girls and sex bias of the IPR task content. The justifiability of separate, average and non-average, IPR indicators application was corroborated by their distribution form differences, by mutual, predominantly low and medium correlations, by the different intensity of their developmental changes and by their different ability to detect sex differences. For all registered phenomena, the theoretical and/or empirical explanations were offered from the domain of sex specific intellectual, motor and neural development, and it has been shown that non

  17. Large-scale variation in boreal and temperate forest carbon turnover rate related to climate

    NASA Astrophysics Data System (ADS)

    Thurner, Martin; Beer, Christian; Carvalhais, Nuno; Forkel, Matthias; Santoro, Maurizio; Tum, Markus; Schmullius, Christiane

    2016-05-01

    Vegetation carbon turnover processes in forest ecosystems and their dominant drivers are far from being understood at a broader scale. Many of these turnover processes act on long timescales and include a lateral dimension and thus can hardly be investigated by plot-level studies alone. Making use of remote sensing-based products of net primary production (NPP) and biomass, here we show that spatial gradients of carbon turnover rate (k) in Northern Hemisphere boreal and temperate forests are explained by different climate-related processes depending on the ecosystem. k is related to frost damage effects and the trade-off between growth and frost adaptation in boreal forests, while drought stress and climate effects on insects and pathogens can explain an elevated k in temperate forests. By identifying relevant processes underlying broadscale patterns in k, we provide the basis for a detailed exploration of these mechanisms in field studies, and ultimately the improvement of their representations in global vegetation models (GVMs).

  18. Reassessing the Relation Between Stellar Mass, Metallicity, and Star Formation Rate in the Local Universe

    NASA Astrophysics Data System (ADS)

    Telford, Olivia Grace; Dalcanton, Julianne; Skillman, Evan D.; Conroy, Charlie

    2015-01-01

    There is considerable evidence that the well-established mass-metallicity relation in galaxies depends on a third parameter: star formation rate (SFR). The observed strength of this dependence varies substantially depending on the choice of metallicity calibration, but has significant implications for theories of galaxy evolution, as it constrains the interplay between infall of pristine gas, metal production due to star formation, and ejection of enriched gas from galaxies. We present a new analysis of the relation between stellar mass, gas phase metallicity and SFR for ~140,000 star-forming galaxies in the Sloan Digital Sky Survey. Using a new set of theoretically calibrated abundance diagnostics from Dopita et al. (2013), we find a weaker dependence of metallicity on SFR at fixed stellar mass than was found by previous studies using different calibration techniques for gas phase metallicity. We analyze possible biases in the derivation of mass, metallicity, and SFR that could cause the observed strength of the metallicity dependence on SFR to differ from reality, as the calculation of each of these quantities is subject to systematic errors. Chemical evolution models must carefully consider these sources of potential bias when accounting for metallicity dependence on SFR.

  19. Relative in vitro growth rates of duckweeds (Lemnaceae) - the most rapidly growing higher plants.

    PubMed

    Ziegler, P; Adelmann, K; Zimmer, S; Schmidt, C; Appenroth, K-J

    2015-01-01

    Relative growth rates (RGR), doubling times (DT) and relative weekly yields (RY) of 39 clones (ecotypes) from 13 species representing all five genera of duckweeds were determined under standardised cultivation conditions. RGR ranged overall from 0.153 to 0.519 day(-1) , DT from 1.34 to 4.54 days and RY from 2.9 to 37.8 week(-1) . The RGR and RY data can be compared directly to other published findings to only a limited extent on account of missing clonal designations for and limited accessibility to previously investigated clones, as well as the use of different data denominators. However, they are consistent with the published results of other comparative duckweed studies of similar scope in showing that RGR does not vary primarily at the level of the genus or species, but rather reflects the adaptation of individual clones to specific local conditions. The RGR data support the widely held assumption that duckweeds can grow faster than other higher plants and that they can thus surpass land-based agricultural crops in productivity. Duckweeds are highly promising for the production of biomass for nutrition and energy, but extensive clonal comparison will be required to identify the most suitable isolates for this purpose. PMID:24803032

  20. We should be using nonlinear indices when relating heart-rate dynamics to cognition and mood

    PubMed Central

    Young, Hayley; Benton, David

    2015-01-01

    Both heart rate (HR) and brain functioning involve the integrated output of a multitude of regulatory mechanisms, that are not quantified adequately by linear approximations such as means and standard deviations. It was therefore considered whether non-linear measures of HR complexity are more strongly associated with cognition and mood. Whilst resting, the inter-beat (R-R) time series of twenty-one males and twenty-four females were measured for five minutes. The data were summarised using time, frequency and nonlinear complexity measures. Attention, memory, reaction times, mood and cortisol levels were assessed. Nonlinear HR indices captured additional information, enabling a greater percentage of the variance in behaviour to be explained. On occasions non-linear indices were related to aspects for behaviour, for example focused attention and cortisol production, when time or frequency indices were not. These effects were sexually dimorphic with HR complexity being more strongly associated with the behaviour of females. It was concluded that nonlinear rather than linear methods of summarizing the HR times series offers a novel way of relating brain functioning and behaviour. It should be considered whether non-linear measures of HR complexity can be used as a biomarker of the integrated functioning of the brain. PMID:26565560

  1. Relative rates of albumin equilibration in the skin interstitium and lymph during vasodilation

    SciTech Connect

    Powers, M.R.; Wallace, J.R.; Bell, D.R.

    1986-03-01

    The initial equilibration of /sup 125/I-labeled albumin between the vascular and extravascular compartments was studied in hindpaw skin of 6 anesthetized rabbits. Papavarine (200 ug/min) was infused into a small branch of the femoral artery of one limb with the contralateral limb as a control. There was a 1.2-fold increase in lymph flow (p < 0.01) with no significant change in the lymph-to-plasma total protein concentration ratio from prepopliteal lymphatics following papavarine. After reaching a constant, elevated lymph flow, tracer labeled albumin was infused to maintain the plasma activity constant for 3 hrs. The plasma volume in tissue samples was measured using /sup 131/I-labeled albumin injected 10 min before ending the experiment. Endogenous albumin was measured in plasma, lymph, and tissue samples using rocket electroimmunoassay. After 3 hrs of tracer infusion, lymph specific activity relative to plasma was significantly greater in the vasodilated hindlimb (0.30 +/- 0.07 vs 0.13 +/- 0.05; mean +/- SE; p < 0.01). Extravascular specific activity relative to plasma was greater in the vasodilated limb (0.13 +/- 0.02 vs 0.09 +/- 0.02; p < 0.05). Thus, vasodilation increased the rates at which lymph and tissue equilibrate with plasma. Also, the difference between lymph and tissue equilibration was greater in the vasodilated hindlimb.

  2. Offenders, Judges, and Officers Rate the Relative Severity of Alternative Sanctions Compared to Prison

    ERIC Educational Resources Information Center

    Moore, Nathan T.; May, David C.; Wood, Peter B.

    2008-01-01

    Recent work suggests that offenders rate several alternatives as more severe than imprisonment. We build on this literature by comparing punishment exchange rates generated by criminal court judges with rates generated by offenders and their supervising officers. Findings reveal that none of the three groups rates prison as the most severe…

  3. The radio continuum-star formation rate relation in WSRT sings galaxies

    SciTech Connect

    Heesen, Volker; Brinks, Elias; Leroy, Adam K.; Heald, George; Braun, Robert; Bigiel, Frank; Beck, Rainer E-mail: v.heesen@soton.ac.uk E-mail: heald@astron.nl E-mail: bigiel@uni-heidelberg.de

    2014-05-01

    We present a study of the spatially resolved radio continuum-star formation rate (RC-SFR) relation using state-of-the-art star formation tracers in a sample of 17 THINGS galaxies. We use SFR surface density (Σ{sub SFR}) maps created by a linear combination of GALEX far-UV (FUV) and Spitzer 24 μm maps. We use RC maps at λλ22 and 18 cm from the WSRT SINGS survey and Hα emission maps to correct for thermal RC emission. We compare azimuthally averaged radial profiles of the RC and FUV/mid-IR (MIR) based Σ{sub SFR} maps and study pixel-by-pixel correlations at fixed linear scales of 1.2 and 0.7 kpc. The ratio of the integrated SFRs from the RC emission to that of the FUV/MIR-based SF tracers is R{sub int}=0.78±0.38, consistent with the relation by Condon. We find a tight correlation between the radial profiles of the radio and FUV/MIR-based Σ{sub SFR} for the entire extent of the disk. The ratio R of the azimuthally averaged radio to FUV/MIR-based Σ{sub SFR} agrees with the integrated ratio and has only quasi-random fluctuations with galactocentric radius that are relatively small (25%). Pixel-by-pixel plots show a tight correlation in log-log diagrams of radio to FUV/MIR-based Σ{sub SFR}, with a typical standard deviation of a factor of two. Averaged over our sample we find (Σ{sub SFR}){sub RC}∝(Σ{sub SFR}){sub hyb}{sup 0.63±0.25}, implying that data points with high Σ{sub SFR} are relatively radio dim, whereas the reverse is true for low Σ{sub SFR}. We interpret this as a result of spectral aging of cosmic-ray electrons (CREs), which are diffusing away from the star formation sites where they are injected into the interstellar medium. This is supported by our finding that the radio spectral index is a second parameter in pixel-by-pixel plots: those data points dominated by young CREs are relatively radio dim, while those dominated by old CREs are slightly more RC bright than what would be expected from a linear extrapolation. We studied the ratio R of

  4. Growth rates of North Sea macroalgae in relation to temperature, irradiance and photoperiod

    NASA Astrophysics Data System (ADS)

    Fortes, M. D.; Lüning, K.

    1980-03-01

    Three eulittoral algae (Ulva lactuca, Porphyra umbilicalis, Chondrus crispus) and one sublittoral alga (Laminaria saccharina) from Helgoland (North Sea) were cultivated in a flow-through system at different temperatures, irradiances and daylengths. In regard to temperature there was a broad optimum at 10 15° C, except in P. umbilicalis, which grew fastest at 10 °C. A growth peak at this temperature was also found in four of 17 other North Sea macroalgae, for which the growth/temperature response was studied, whereas 13 of these species exhibited a growth optimum at 15 °C, or a broad optimum at 10 15 °C. Growth was light-saturated in U. lactuca, L. saccharina and C. crispus at photon flux densities above 70 µE m-2s-1, but in P. umbilicalis above 30 µE m-2s-1. Growth rate did not decrease notably in the eulittoral species after one week in relatively strong light (250 µE m-2s-1), but by about 50 % in the case of the sublittoral L. saccharina, as compared with growth under weak light conditions (30 µE m-2s-1). In contrast, chlorophyll content decreased in the sublittoral as well as in the eulittoral species, and the greatest change in pigment content occurred in the range 30 70 µE m-2s-1. Growth rate increased continuously up to photoperiods of 24 h light per day in L. saccharina and C. crispus, whereas daylength saturation occurred at photoperiods of more than 16 h light per day in U. lactuca and P. umbilicalis.

  5. Breast Cancer-Related Arm Lymphedema: Incidence Rates, Diagnostic Techniques, Optimal Management and Risk Reduction Strategies

    SciTech Connect

    Shah, Chirag; Vicini, Frank A.

    2011-11-15

    As more women survive breast cancer, long-term toxicities affecting their quality of life, such as lymphedema (LE) of the arm, gain importance. Although numerous studies have attempted to determine incidence rates, identify optimal diagnostic tests, enumerate efficacious treatment strategies and outline risk reduction guidelines for breast cancer-related lymphedema (BCRL), few groups have consistently agreed on any of these issues. As a result, standardized recommendations are still lacking. This review will summarize the latest data addressing all of these concerns in order to provide patients and health care providers with optimal, contemporary recommendations. Published incidence rates for BCRL vary substantially with a range of 2-65% based on surgical technique, axillary sampling method, radiation therapy fields treated, and the use of chemotherapy. Newer clinical assessment tools can potentially identify BCRL in patients with subclinical disease with prospective data suggesting that early diagnosis and management with noninvasive therapy can lead to excellent outcomes. Multiple therapies exist with treatments defined by the severity of BCRL present. Currently, the standard of care for BCRL in patients with significant LE is complex decongestive physiotherapy (CDP). Contemporary data also suggest that a multidisciplinary approach to the management of BCRL should begin prior to definitive treatment for breast cancer employing patient-specific surgical, radiation therapy, and chemotherapy paradigms that limit risks. Further, prospective clinical assessments before and after treatment should be employed to diagnose subclinical disease. In those patients who require aggressive locoregional management, prophylactic therapies and the use of CDP can help reduce the long-term sequelae of BCRL.

  6. The interplay between aerobic metabolism and antipredator performance: vigilance is related to recovery rate after exercise

    PubMed Central

    Killen, Shaun S.; Reid, Donald; Marras, Stefano; Domenici, Paolo

    2015-01-01

    When attacked by a predator, fish respond with a sudden fast-start motion away from the threat. Although this anaerobically-powered swimming necessitates a recovery phase which is fueled aerobically, little is known about links between escape performance and aerobic traits such as aerobic scope (AS) or recovery time after exhaustive exercise. Slower recovery ability or a reduced AS could make some individuals less likely to engage in a fast-start response or display reduced performance. Conversely, increased vigilance in some individuals could permit faster responses to an attack but also increase energy demand and prolong recovery after anaerobic exercise. We examined how AS and the ability to recover from anaerobic exercise relates to differences in fast-start escape performance in juvenile golden gray mullet at different acclimation temperatures. Individuals were acclimated to either 18, 22, or 26°C, then measured for standard and maximal metabolic rates and AS using intermittent flow respirometry. Anaerobic capacity and the time taken to recover after exercise were also assessed. Each fish was also filmed during a simulated attack to determine response latency, maximum speed and acceleration, and turning rate displayed during the escape response. Across temperatures, individuals with shorter response latencies during a simulated attack are those with the longest recovery time after exhaustive anaerobic exercise. Because a short response latency implies high preparedness to escape, these results highlight the trade-off between the increased vigilance and metabolic demand, which leads to longer recovery times in fast reactors. These results improve our understanding of the intrinsic physiological traits that generate inter-individual variability in escape ability, and emphasize that a full appreciation of trade-offs associated with predator avoidance and energy balance must include energetic costs associated with vigilance and recovery from anaerobic exercise

  7. Effectiveness Ratings of Counselors by Coached Clients Related to Attractiveness-Fitness Variables.

    ERIC Educational Resources Information Center

    Wiggins, J. D.

    1980-01-01

    Rated normal-weight and overweight male and female counselors on perceived cognitive effectiveness, warmth and empathy, leadership qualities, and global counseling effectiveness. Although all counselors were rated as competent, both male and female counselors who were overweight were rated as less able in all areas tested. (Author)

  8. Peer Ratings of Aggression: Relation to Social Skills, Behavior Problems, and Friendships.

    ERIC Educational Resources Information Center

    McIntosh, Ruth; Vaughn, Sharon

    This study examined the aggressive behaviors of children through peer ratings to teacher ratings of problem behaviors and social skills and peer ratings of friendship. Peer data are valid measures and may be more accurate than teacher or self measures because peers are more likely to be present when aggression occurs. This study examines a peer…

  9. Protein expression and oxygen consumption rate of early postmortem mitochondria relate to meat tenderness.

    PubMed

    Grabež, V; Kathri, M; Phung, V; Moe, K M; Slinde, E; Skaugen, M; Saarem, K; Egelandsdal, B

    2015-04-01

    Oxygen consumption rate (OCR) of muscle fibers from bovine semimembranosus muscle of 41 animals was investigated 3 to 4 h and 3 wk postmortem. Significant relations (P < 0.05) were found between OCR measurements and Warner-Bratzler shear force measurement. Muscles with high mitochondrial OCR after 3 to 4 h and low nonmitochondrial oxygen consumption gave more tender meat. Tender (22.92 ± 2.2 N/cm2) and tough (72.98 ± 7.2 N/cm2) meat samples (4 samples each), separated based on their OCR measurements, were selected for proteomic studies using mitochondria isolated approximately 2.5 h postmortem. Twenty-six differently expressed proteins (P < 0.05) were identified in tender meat and 19 in tough meat. In tender meat, the more prevalent antioxidant and chaperon enzymes may reduce reactive oxygen species and prolong oxygen removal by the electron transport system (ETS). Glycolytic, Krebs cycle, and ETS enzymes were also more abundant in tender meat PMID:26020220

  10. Reasoning with base rates is routine, relatively effortless, and context dependent.

    PubMed

    Pennycook, Gordon; Thompson, Valerie A

    2012-06-01

    We tested models of base rate "neglect" using a novel paradigm. Participants (N = 62) judged the probability that a hypothetical person belonged to one of two categories (e.g., nurse/doctor) on the basis of either a personality description alone (NoBR) or the personality description and a base rate probability (BR). When base rates and descriptions were congruent, judgments in the BR condition were higher and more uniform than those in the NoBR condition. In contrast, base rates had a polarizing effect on judgments when they were incongruent with the descriptions, such that estimates were either consistent with the base rates or discrepant with them. These data suggest that the form of base rate use (i.e., whether base rates will be integrated with diagnostic information) is context dependent. In addition, judgments made under instructions to respond intuitively were influenced by the base rates and took the same length of time in the two conditions. These data suggest that the use of base rates is routine and effortless and that base rate "neglect" is really a mixture of two strategies, one that is informed primarily by the base rate and the other by the personality description. PMID:22427266

  11. Hospital injury rates in relation to socioeconomic status and working conditions

    PubMed Central

    d'Errico, A; Punnett, L; Cifuentes, M; Boyer, J; Tessler, J; Gore, R; Scollin, P

    2007-01-01

    Objectives To describe the risk of work injury by socioeconomic status (SES) in hospital workers, and to assess whether SES gradient in injury risk is explained by differences in psychosocial, ergonomic or organisational factors at work. Methods Workforce rosters and Occupational Safety and Health Administration injury logs for a 5‐year period were obtained from two hospitals in Massachusetts. Job titles were classified into five SES strata on the basis of educational requirements and responsibilities: administrators, professionals, semiprofessionals, skilled and semiskilled workers. 13 selected psychosocial, ergonomic and organisational exposures were assigned to the hospital jobs through the national O*NET database. Rates of injury were analysed as frequency records using the Poisson regression, with job title as the unit of analysis. The risk of injury was modelled using SES alone, each exposure variable alone and then each exposure variable in combination with SES. Results An overall annual injury rate of 7.2 per 100 full‐time workers was estimated for the two hospitals combined. All SES strata except professionals showed a significant excess risk of injury compared with the highest SES category (administrators); the risk was highest among semiskilled workers (RR 5.3, p<0.001), followed by nurses (RR 3.7, p<0.001), semiprofessionals (RR 2.9, p = 0.006) and skilled workers (RR 2.6, p = 0.01). The risk of injury was significantly associated with each exposure considered except pause frequency. When workplace exposures were introduced in the regression model together with SES, four remained significant predictors of the risk of injury (decision latitude, supervisor support, force exertion and temperature extremes), whereas the RR related to SES was strongly reduced in all strata, except professionals. Conclusions A strong gradient in the risk of injury by SES was reported in a sample population of hospital workers, which was greatly attenuated by

  12. The Relation Between Accretion Rate And Jet Power in X-Ray Luminous Elliptical Galaxies

    SciTech Connect

    Allen, Steven W.; Dunn, R.J.H.; Fabian, A.C.; Taylor, G.B.; Reynolds, C.S.; /Maryland U.

    2006-03-10

    Using Chandra X-ray observations of nine nearby, X-ray luminous elliptical galaxies with good optical velocity dispersion measurements, we show that a tight correlation exists between the Bondi accretion rates calculated from the observed gas temperature and density profiles and estimated black hole masses, and the power emerging from these systems in relativistic jets. The jet powers, which are inferred from the energies and timescales required to inflate cavities observed in the surrounding X-ray emitting gas, can be related to the accretion rates using a power law model of the form log (P{sub Bondi}/10{sup 43} erg s{sup -1}) = A + B log (P{sub jet}/10{sup 43} erg s{sup -1}), with A = 0.62 {+-} 0.15 and B = 0.77 {+-} 0.18. Our results show that a significant fraction of the energy associated with the rest mass of material entering the Bondi accretion radius (2.4{sub -0.7}{sup +1.0} per cent, for P{sub jet} = 10{sup 43} erg s{sup -1}) eventually emerges in the relativistic jets. Our results have significant implications for studies of accretion, jet formation and galaxy formation. The observed tight correlation suggests that the Bondi formulae provide a reasonable description of the accretion process in these systems, despite the likely presence of magnetic pressure and angular momentum in the accreting gas. The similarity of the P{sub Bondi} and P{sub jet} values argues that a significant fraction of the matter entering the accretion radius flows down to regions close to the black holes, where the jets are presumably formed. The tight correlation between P{sub Bondi} and P{sub jet} also suggests that the accretion flows are approximately stable over timescales of a few million years. Our results show that the black hole ''engines'' at the hearts of large elliptical galaxies and groups feed back sufficient energy to stem cooling and star formation, leading naturally to the observed exponential cut off at the bright end of the galaxy luminosity function.

  13. Differences in Hispanic Access and Success Rates for Health-Related Studies in Texas Health-Related Institutions: A Multiyear, Statewide Investigation

    ERIC Educational Resources Information Center

    Cox, Shelley M.

    2013-01-01

    Purpose: The purpose of this study was to examine Hispanic student access and success in health-related degrees by examining enrollment and graduation rates over a period of 13 years. Archival data were obtained from the THECB consisting of the number of Hispanic students enrolled and number of degrees awarded in the health-related degrees at…

  14. Tri-Axial Accelerometry and Heart Rate Telemetry: Relation and Agreement with Behavioral Observation in Elementary Physical Education

    ERIC Educational Resources Information Center

    Scruggs, Philip W.; Beveridge, Sandy K.; Clocksin, Brian D.

    2005-01-01

    The relation and agreement of tri-axial accelerometry and heart rate telemetry in measuring moderate to vigorous physical activity were examined in association to behavioral observation during 1st- and 2nd-grade physical education. In Study 1, physical activity measures of heart rate and behavioral observation were collected on 346 participants…

  15. Relations between Perceived Competence, Importance Ratings, and Self-Worth among African American School-Age Children

    ERIC Educational Resources Information Center

    Grier, Leslie K.

    2013-01-01

    The purpose of this research was to investigate how domain-specific importance ratings affect relations between perceived competence and self-worth among African American school-age children. Importance ratings have been found to affect the strength of the relationship between perceived competence and self-worth and have implications for…

  16. Do Small Rural High Schools Differ from Larger Schools in Relation to Absentee Rates in Physical Education?

    ERIC Educational Resources Information Center

    Lagestad, Pal; Ranes, Vebjorn; Welde, Boye

    2015-01-01

    The aims of the study were twofold: (a) to investigate how school size affects absentee rates in physical education (PE) and (b) to examine the experiences of students and teachers at a small rural high school in relation to attendance in PE at their school. The absentee rates in PE among all students (N = 6928 students) in a county in Norway were…

  17. Hikurangi Margin: Geology, Flow Rates, Water-Rock Interaction and Relative Fluid Ages

    NASA Astrophysics Data System (ADS)

    Reyes, A. G.

    2014-12-01

    The subaerial part of the Hikurangi Accretionary Prism (HAP) has nearly 330 sources of saline waters (2000-26000 mg/kg Cl), SO4-rich waters, CH4-rich gases and occasional oil seeps discharging from springs, mud volcanoes and gas vents from -37.5o to -41.3o latitude, 80-100 km from the subduction margin. Discharge areas, occupying <0.01 to 11 ha each, form a band about 500 km in length with widths ranging from 25 km in the south to 75-100 km in the north and centre. All fluid discharges are cold except for two hot springs in the central and N segments and another 6 on the W margin of the HAP. The total flow rate along the HAP is at least 10 x 108L/a, with nearly 50% contributed by cold discharges. Most fluid manifestations emerge along NE-trending faults and minor structures such as anticlines and synclines. However in the N, where fluids are also discharged along NW- and EW-trending structures within the allochton, manifestations are relatively more abundant (>150 sites), discharging nearly 45% of the annual surface fluid volume along the HAP. Fluid discharges in the HAP, based on chemical and isotopic fluid compositions, consist of subducted waters derived from clay water of hydration (<50%) and seawater that had interacted at varying degrees with organic-containing sedimentary rocks at depth at different temperatures. Discharges from the central segment exhibit the lowest degree of water-rock interaction and have the highest inferred subsurface temperatures (median: 110oC compared to S at 80oC and N at 90oC), suggesting (1) more recent influx of subducted waters and (2) more rapid upflow of fluids from depth, relative to the S and N. Fluids in the S segment exhibit the highest degree of water-rock interaction suggesting longer residence time at depth, or slower fluid movement to the surface due to thicker crust or greater fluid channel tortuosity. The high concentration of isotopic He in the central and N fluids can be due to deep and highly permeable faults that

  18. Structure/property relations of aluminum under varying rates and stress states

    SciTech Connect

    Tucker, Matthew T; Horstemeyer, Mark F; Whittington, Wilburn R; Solanki, Kiran N

    2010-11-19

    In this work we analyze the plasticity, damage, and fracture characteristics of three different processed aluminum alloys (rolled 5083-H13, cast A356-T6, and extruded 6061-T6) under varying stress states (tension, compression, and torsion) and strain rates (0.001/, 1/s., and 1000/s). The stress state difference had more of a flow stress effect than the applied strain rates for those given in this study (0.001/sec up to 1000/sec). The stress state and strain rate also had a profound effect on the damage evolution of each aluminum alloy. Tension and torsional straining gave much greater damage nucleation rates than compression. Although the damage of all three alloys was found to be void nucleation dominated, the A356-T6 and 5083-H131 aluminum alloys incurred void damage via micron scale particles where the 6061-T6 aluminum alloy incurred void damage from two scales, micron-scale particles and nanoscale precipitates. Having two length scales of particles that participated in the damage evolution made the 6061-T6 incur a strain rate sensitive damage rate that was different than the other two aluminum alloys. Under tension, as the strain rate increased, the 6061-T6 aluminum alloy's void nucleation rate decreased, but the A356-T6 and 5083-H131 aluminum alloys void nucleation rate increased.

  19. Catch rates relative to angler party size with implications for monitoring angler success

    USGS Publications Warehouse

    Miranda, L.E.

    2005-01-01

    Angler catch rates often are used to monitor angler success, assess the need for additional management actions, and evaluate the effectiveness of management practices. Potential linkages between catch rate and angler party size were examined to assess how party size might affect the use of catch rate as an index of angler success in recreational fisheries. Data representing 22,355 completed interviews conducted at access points in lakes and reservoirs throughout Mississippi during 1987-2003 were analyzed. Total party catch was not proportional to total party effort; thus, catch rate decreased as party size increased. Depending on the taxa targeted, the average catch rate per angler decreased 40-50% between parties of one and parties of two, although subsequent decreases were less substantial. Because party size accounted for a considerable portion of the variability in catch rate over time and space, failure to remove this variability weakens the manager's ability to detect differences or changes in catch rates. Therefore, the use of catch rates to monitor fisheries may be inappropriate unless party size is taken into account. Party size may influence the angler's ability to catch fish through a variety of processes, including partitioning a limited number of catchable fish among members of a party and party composition. When catch rates are used to estimate total catch rather than to index angler success, party size is not a concern.

  20. Interannual variability of the atmospheric CO2 growth rate: relative contribution from precipitation and temperature

    NASA Astrophysics Data System (ADS)

    Wang, J.; Zeng, N.; Wang, M. R.

    2015-12-01

    The interannual variability (IAV) in atmospheric CO2 growth rate (CGR) is closely connected with the El Niño-Southern Oscillation. However, sensitivities of CGR to temperature and precipitation remain largely uncertain. This paper analyzed the relationship between Mauna Loa CGR and tropical land climatic elements. We find that Mauna Loa CGR lags precipitation by 4 months with a correlation coefficient of -0.63, leads temperature by 1 month (0.77), and correlates with soil moisture (-0.65) with zero lag. Additionally, precipitation and temperature are highly correlated (-0.66), with precipitation leading by 4-5 months. Regression analysis shows that sensitivities of Mauna Loa CGR to temperature and precipitation are 2.92 ± 0.20 Pg C yr-1 K-1 and -0.46 ± 0.07 Pg C yr-1 100 mm-1, respectively. Unlike some recent suggestions, these empirical relationships favor neither temperature nor precipitation as the dominant factor of CGR IAV. We further analyzed seven terrestrial carbon cycle models, from the TRENDY project, to study the processes underlying CGR IAV. All models capture well the IAV of tropical land-atmosphere carbon flux (CFTA). Sensitivities of the ensemble mean CFTA to temperature and precipitation are 3.18 ± 0.11 Pg C yr-1 K-1 and -0.67 ± 0.04 Pg C yr-1 100 mm-1, close to Mauna Loa CGR. Importantly, the models consistently show the variability in net primary productivity (NPP) dominates CGR, rather than soil respiration. Because NPP is largely driven by precipitation, this suggests a key role of precipitation in CGR IAV despite the higher CGR correlation with temperature. Understanding the relative contribution of CO2 sensitivity to precipitation and temperature has important implications for future carbon-climate feedback using such "emergent constraint".

  1. Baroreflex sensitivity assessment and heart rate variability: relation to maneuver and technique.

    PubMed

    Carrasco-Sosa, S; Gaitán-González, M J; González-Camarena, R; Yáñez-Suárez, Oscar

    2005-10-01

    In the present study, we examined two baroreflex sensitivity (BRS) issues that remain uncertain: the differences among diverse BRS assessment techniques and the association between BRS and vagal outflow. Accordingly, the electrocardiogram and non-invasive arterial pressure were recorded in 27 healthy subjects, during supine with and without controlled breathing, standing, exercise, and recovery conditions. Vagal outflow was estimated by heart rate variability indexes, whereas BRS was computed by alpha-coefficient, transfer function, complex demodulation in low- and high-frequency bands, and by sequence technique. Our results indicated that only supine maneuvers showed significantly greater BRS values over the high frequency than in the low-frequency band. For maneuvers at the same frequency region, supine conditions presented a larger number of significant differences among techniques. The plots between BRS and vagal measures depicted a funnel-shaped relationship with significant log-log correlations (r=0.880-0.958). Very short latencies between systolic pressure and RR interval series in high-frequency band and strong log-log correlations between frequency bands were found. Higher variability among different baroreflex measurements was associated with higher level of vagal outflow. Methodological assumptions for each technique seem affected by non-baroreflex variation sources, and a modified responsiveness of vagal motoneurons due to distinct stimulation levels for each maneuver was suggested. Thus, highest vagal outflows corresponded to greatest BRS values, with maximum respiratory effect for the high-frequency band values. In conclusion, BRS values and differences across the tested techniques were strongly related to the vagal outflow induced by the maneuvers. PMID:16086148

  2. A Bayesian hierarchical model for reconstructing relative sea level: from raw data to rates of change

    NASA Astrophysics Data System (ADS)

    Cahill, N.; Kemp, A. C.; Horton, B. P.; Parnell, A. C.

    2015-10-01

    We present a holistic Bayesian hierarchical model for reconstructing the continuous and dynamic evolution of relative sea-level (RSL) change with fully quantified uncertainty. The reconstruction is produced from biological (foraminifera) and geochemical (δ13C) sea-level indicators preserved in dated cores of salt-marsh sediment. Our model is comprised of three modules: (1) A Bayesian transfer function for the calibration of foraminifera into tidal elevation, which is flexible enough to formally accommodate additional proxies (in this case bulk-sediment δ13C values), (2) A chronology developed from an existing Bchron age-depth model, and (3) An existing errors-in-variables integrated Gaussian process (EIV-IGP) model for estimating rates of sea-level change. We illustrate our approach using a case study of Common Era sea-level variability from New Jersey. USA We develop a new Bayesian transfer function (B-TF), with and without the δ13C proxy and compare our results to those from a widely-used weighted-averaging transfer function (WA-TF). The formal incorporation of a second proxy into the B-TF model results in smaller vertical uncertainties and improved accuracy for reconstructed RSL. The vertical uncertainty from the multi-proxy B-TF is ∼ 28 % smaller on average compared to the WA-TF. When evaluated against historic tide-gauge measurements, the multi-proxy B-TF most accurately reconstructs the RSL changes observed in the instrumental record (MSE = 0.003 m2). The holistic model provides a single, unifying framework for reconstructing and analysing sea level through time. This approach is suitable for reconstructing other paleoenvironmental variables using biological proxies.

  3. A Systemic Review of Autologous Fat Grafting Survival Rate and Related Severe Complications

    PubMed Central

    Yu, Nan-Ze; Huang, Jiu-Zuo; Zhang, Hao; Wang, Yang; Wang, Xiao-Jun; Zhao, Ru; Bai, Ming; Long, Xiao

    2015-01-01

    Objective: Clinical application of autologous fat grafting (AFG) is quickly expanding. Despite the widely acceptance, long-term survival rate (SR) of AFG remains a question not yet solved. Meanwhile, although rare, severe complications related to AFG including vision loss, stroke even death could be seen in the literature. Data Sources: A comprehensive research of PubMed database to June 2013 was performed according to guidelines of the American Society of Plastic Surgeons Fat Graft Task Force Assessment Methodology. Articles were screened using predetermined inclusion and exclusion criteria. Study Selection: Data collected included patient characteristics, surgical technique, donor site, recipient site, graft amount, and quantified measurement methods. Patient cohorts were pooled, and SR was calculated. All the severe complications were also summarized according to the different clinical characteristics. Results: Of 550 articles, 16 clinical articles and 10 animal studies met the inclusion criteria and provided quantified measurement methods. Totally, 596 patients were included. SR varied from 34% to 82% in breast and 30–83% in the facial area. Nude mice were applied to investigate human fat grafting SR (38.3–52.5% after 15 weeks). Rabbits were commonly used to study animal AFG SR (14.00–14.56% after 1-year). Totally, 21 severe complications were reported, including death (2), stroke (10), vision loss (11, 8 of which accompanied with stroke), sepsis (3), multiple abscess (1) and giant fat necrotic cyst (2). Ten of these complications happened within 10 years. Conclusions: There is no unified measurement method to evaluate fat graft SR until now and no clinical evidence to show better SR according to different donor and recipient cite. Body mass index change between pre- and postoperation may be the bias factor in evaluating fat SR. Fat embolisms of the ophthalmic artery and the middle cerebral artery are the most severe complication of AFG and still lack of

  4. A Bayesian hierarchical model for reconstructing relative sea level: from raw data to rates of change

    NASA Astrophysics Data System (ADS)

    Cahill, Niamh; Kemp, Andrew C.; Horton, Benjamin P.; Parnell, Andrew C.

    2016-02-01

    We present a Bayesian hierarchical model for reconstructing the continuous and dynamic evolution of relative sea-level (RSL) change with quantified uncertainty. The reconstruction is produced from biological (foraminifera) and geochemical (δ13C) sea-level indicators preserved in dated cores of salt-marsh sediment. Our model is comprised of three modules: (1) a new Bayesian transfer (B-TF) function for the calibration of biological indicators into tidal elevation, which is flexible enough to formally accommodate additional proxies; (2) an existing chronology developed using the Bchron age-depth model, and (3) an existing Errors-In-Variables integrated Gaussian process (EIV-IGP) model for estimating rates of sea-level change. Our approach is illustrated using a case study of Common Era sea-level variability from New Jersey, USA We develop a new B-TF using foraminifera, with and without the additional (δ13C) proxy and compare our results to those from a widely used weighted-averaging transfer function (WA-TF). The formal incorporation of a second proxy into the B-TF model results in smaller vertical uncertainties and improved accuracy for reconstructed RSL. The vertical uncertainty from the multi-proxy B-TF is ˜ 28 % smaller on average compared to the WA-TF. When evaluated against historic tide-gauge measurements, the multi-proxy B-TF most accurately reconstructs the RSL changes observed in the instrumental record (mean square error = 0.003 m2). The Bayesian hierarchical model provides a single, unifying framework for reconstructing and analyzing sea-level change through time. This approach is suitable for reconstructing other paleoenvironmental variables (e.g., temperature) using biological proxies.

  5. Relative impact of mate versus pollinator availability on pollen limitation and outcrossing rates in a mass-flowering species.

    PubMed

    Delmas, C E L; Escaravage, N; Cheptou, P-O; Charrier, O; Ruzafa, S; Winterton, P; Pornon, A

    2015-01-01

    Plant mating systems are driven by several pre-pollination factors, including pollinator availability, mate availability and reproductive traits. We investigated the relative contributions of these factors to pollination and to realized outcrossing rates in the patchily distributed mass-flowering shrub Rhododendron ferrugineum. We jointly monitored pollen limitation (comparing seed set from intact and pollen-supplemented flowers), reproductive traits (herkogamy, flower size and autofertility) and mating patterns (progeny array analysis) in 28 natural patches varying in the level of pollinator availability (flower visitation rates) and of mate availability (patch floral display estimated as the total number of inflorescences per patch). Our results showed that patch floral display was the strongest determinant of pollination and of the realized outcrossing rates in this mass-flowering species. We found an increase in pollen limitation and in outcrossing rates with increasing patch floral display. Reproductive traits were not significantly related to patch floral display, while autofertility was negatively correlated to outcrossing rates. These findings suggest that mate limitation, arising from high flower visitation rates in small plant patches, resulted in low pollen limitation and high selfing rates, while pollinator limitation, arising from low flower visitation rates in large plant patches, resulted in higher pollen limitation and outcrossing rates. Pollinator-mediated selfing and geitonogamy likely alleviates pollen limitation in the case of reduced mate availability, while reduced pollinator availability (intraspecific competition for pollinator services) may result in the maintenance of high outcrossing rates despite reduced seed production. PMID:24942604

  6. Are age-related trends in suicide rates associated with life expectancy and socio-economic factors?

    PubMed

    Shah, Ajit

    2009-01-01

    Background. A recent cross-national study reported that suicide rates increased, decreased or remained unchanged with increasing age in individual countries. The relationship between age-related trends in suicide rates and child mortality rates, life expectancy and socio-economic factors was examined. Methods. Countries with an increase, decrease and no change in suicide rates with increasing age were ascertained from an earlier study (Shah, 2007a, International Psychogeriatrics, 19, 1141), which analysed data from the World Health Organisation (WHO). The relationship between age-related trends in suicide rates and (i) child mortality rates, (ii) life expectancy and (iii) markers of socio-economic status (per capita gross national domestic product (GDP) and the Gini coeffcient) was examined using data from the WHO and the United Nations. Results. The main findings were: (i) child mortality rates were significantly lower in countries with an increase in suicide rates with increasing age when compared to countries without a change in suicide rates with increasing age in males; (ii) life expectancy was significantly higher in countries with an increase in suicide rates with increasing age when compared to countries without a change in suicide rates with increasing age in males; and (iii) the Gini coefficient was significantly lower in countries with an increase in suicide rates with increasing age when compared to countries without a change or a decline in suicide rates with increasing age in females. Conclusions. Potential explanations for these findings and the interaction of life expectancy and socio-economic factors with other factors that differentially influence suicide rates in different age and sex groups requires further examination. PMID:24946117

  7. Problem Behavior and Heart Rate Reactivity in Adopted Adolescents: Longitudinal and Concurrent Relations

    ERIC Educational Resources Information Center

    Bimmel, Nicole; van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Juffer, Femmie; De Geus, Eco J. C.

    2008-01-01

    The present longitudinal study examined resting heart rate and heart rate variability and reactivity to a stressful gambling task in adopted adolescents with aggressive, delinquent, or internalizing behavior problems and adopted adolescents without behavior problems (total N=151). Early-onset delinquent adolescents showed heart rate…

  8. Addition by Subtraction: The Relation between Dropout Rates and School-Level Academic Achievement

    ERIC Educational Resources Information Center

    Glennie, Elizabeth; Bonneau, Kara; vanDellen, Michelle; Dodge, Kenneth A.

    2012-01-01

    Background/Context: Efforts to improve student achievement should increase graduation rates. However, work investigating the effects of student-level accountability has consistently demonstrated that increases in the standards for high school graduation are correlated with increases in dropout rates. The most favored explanation for this finding…

  9. Rate of Acquiring and Processing L2 Color Words in Relation to L1 Phonological Awareness

    ERIC Educational Resources Information Center

    Hu, Chieh-Fang

    2008-01-01

    This study examined the effect of first language (L1) phonological awareness on the rate of learning new second language (L2) color terms and the rate of processing old color terms. Two groups of 37 children participated; they differed on L1 phonological awareness measured at Grade 3. At Grade 5, over multiple trials, the children learned new L2…

  10. Research on Mail Surveys: Response Rates and Methods in Relation to Population Group and Time.

    ERIC Educational Resources Information Center

    Boser, Judith A.; Green, Kathy

    The purpose of this review was to look for trends across time in response rates and variables studied for published mail surveys and to compare response rates and variables studied for different target populations. Studies were identified in databases in four fields: education, psychology, business and marketing, and sociology. A total of 225…