Sample records for observe strong evidence

  1. Observational Evidence for Small-Scale Mixture of Weak and Strong Fields in the Quiet Sun

    NASA Astrophysics Data System (ADS)

    Socas-Navarro, H.; Lites, B. W.

    2004-11-01

    Three different maps of the quiet Sun, observed with the Advanced Stokes Polarimeter (ASP) and the Diffraction-Limited Stokes Polarimeter (DLSP), show evidence of strong (~=1700 G) and weak (<500 G) fields coexisting within the resolution element at both network and internetwork locations. The angular resolution of the observations is of 1" (ASP) and 0.6" (DLSP). Even at the higher DLSP resolution, a significant fraction of the network magnetic patches harbor a mixture of strong and weak fields. Internetwork elements that exhibit kG fields when analyzed with a single-component atmosphere are also shown to harbor considerable amounts of weak fields. Only those patches for which a single-component analysis yields weak fields do not show this mixture of field strengths. Finally, there is a larger fractional area of weak fields in the convective upflows than in the downflows.

  2. Evidence for a glassy state in strongly driven carbon

    DOE PAGES

    Brown, C. R. D.; Gericke, D. O.; Cammarata, M.; ...

    2014-06-09

    Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen closemore » to their original positions in the fluid.« less

  3. Observational evidence of the complementary relationship in regional evaporation lends strong support for Bouchet's hypothesis

    Treesearch

    Jorge A. Ramirez; Michael T. Hobbins; Thomas C. Brown

    2005-01-01

    Using independent observations of actual and potential evapotranspiration at a wide range of spatial scales, we provide direct observational evidence of the complementary relationship in regional evapotranspiration hypothesized by Bouchet in 1963. Bouchet proposed that, for large homogeneous surfaces with minimal advection of heat and moisture, potential and actual...

  4. Observational evidence for black holes

    NASA Astrophysics Data System (ADS)

    Hutchings, J. B.

    1985-02-01

    Observational data supporting the existence of black holes are presented graphically and characterized in a general review. Object classes discussed include quasars as galaxy cores, X-ray-emitting binaries (Cyg X-1, LMC X-3, and the apparent miniature quasar SS 433), radio galaxies and quasars with twin jets, and interacting galaxies. This evidence is found to strongly suggest that quasars are accreting black holes of mass about 10 to the 8th solar mass, that they formed more easily in earlier stages of the universe (corresponding to redshifts around 2), and that they are analogous in many ways to the stellar-mass object SS 433.

  5. Rejection of unfair offers in the ultimatum game is no evidence of strong reciprocity.

    PubMed

    Yamagishi, Toshio; Horita, Yutaka; Mifune, Nobuhiro; Hashimoto, Hirofumi; Li, Yang; Shinada, Mizuho; Miura, Arisa; Inukai, Keigo; Takagishi, Haruto; Simunovic, Dora

    2012-12-11

    The strong reciprocity model of the evolution of human cooperation has gained some acceptance, partly on the basis of support from experimental findings. The observation that unfair offers in the ultimatum game are frequently rejected constitutes an important piece of the experimental evidence for strong reciprocity. In the present study, we have challenged the idea that the rejection response in the ultimatum game provides evidence of the assumption held by strong reciprocity theorists that negative reciprocity observed in the ultimatum game is inseparably related to positive reciprocity as the two sides of a preference for fairness. The prediction of an inseparable relationship between positive and negative reciprocity was rejected on the basis of the results of a series of experiments that we conducted using the ultimatum game, the dictator game, the trust game, and the prisoner's dilemma game. We did not find any correlation between the participants' tendencies to reject unfair offers in the ultimatum game and their tendencies to exhibit various prosocial behaviors in the other games, including their inclinations to positively reciprocate in the trust game. The participants' responses to postexperimental questions add support to the view that the rejection of unfair offers in the ultimatum game is a tacit strategy for avoiding the imposition of an inferior status.

  6. Rejection of unfair offers in the ultimatum game is no evidence of strong reciprocity

    PubMed Central

    Yamagishi, Toshio; Horita, Yutaka; Mifune, Nobuhiro; Hashimoto, Hirofumi; Li, Yang; Shinada, Mizuho; Miura, Arisa; Inukai, Keigo; Takagishi, Haruto; Simunovic, Dora

    2012-01-01

    The strong reciprocity model of the evolution of human cooperation has gained some acceptance, partly on the basis of support from experimental findings. The observation that unfair offers in the ultimatum game are frequently rejected constitutes an important piece of the experimental evidence for strong reciprocity. In the present study, we have challenged the idea that the rejection response in the ultimatum game provides evidence of the assumption held by strong reciprocity theorists that negative reciprocity observed in the ultimatum game is inseparably related to positive reciprocity as the two sides of a preference for fairness. The prediction of an inseparable relationship between positive and negative reciprocity was rejected on the basis of the results of a series of experiments that we conducted using the ultimatum game, the dictator game, the trust game, and the prisoner’s dilemma game. We did not find any correlation between the participants’ tendencies to reject unfair offers in the ultimatum game and their tendencies to exhibit various prosocial behaviors in the other games, including their inclinations to positively reciprocate in the trust game. The participants’ responses to postexperimental questions add support to the view that the rejection of unfair offers in the ultimatum game is a tacit strategy for avoiding the imposition of an inferior status. PMID:23188801

  7. Observational evidence and strength of evidence domains: case examples

    PubMed Central

    2014-01-01

    Background Systematic reviews of healthcare interventions most often focus on randomized controlled trials (RCTs). However, certain circumstances warrant consideration of observational evidence, and such studies are increasingly being included as evidence in systematic reviews. Methods To illustrate the use of observational evidence, we present case examples of systematic reviews in which observational evidence was considered as well as case examples of individual observational studies, and how they demonstrate various strength of evidence domains in accordance with current Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Center (EPC) methods guidance. Results In the presented examples, observational evidence is used when RCTs are infeasible or raise ethical concerns, lack generalizability, or provide insufficient data. Individual study case examples highlight how observational evidence may fulfill required strength of evidence domains, such as study limitations (reduced risk of selection, detection, performance, and attrition); directness; consistency; precision; and reporting bias (publication, selective outcome reporting, and selective analysis reporting), as well as additional domains of dose-response association, plausible confounding that would decrease the observed effect, and strength of association (magnitude of effect). Conclusions The cases highlighted in this paper demonstrate how observational studies may provide moderate to (rarely) high strength evidence in systematic reviews. PMID:24758494

  8. ZINGRS: CO2-1 observations of strong C+ emitters at z~2

    NASA Astrophysics Data System (ADS)

    Scrabeck, Alex; Ferkinhoff, Carl; Brisbin, Drew; Lamarche, Cody; Vishwas, Amit; Nikola, Thomas; Stacey, Gordon J.; Higdon, James L.; Higdon, Sarah; Walter, Fabian; Decarli, Roberto

    2018-06-01

    We present new CO(2-1) line observations from NOEMA of five strong C+ emitting galaxies at high redshift. These galaxies, pulled from the Zeus INvestigated Galaxy Reference Sample (ZINGRS), were observed in their [CII] 158 micron line with the ZEUS instrument showing strong emission, 1 to 2% of their total far-IR luminosity. Our previous work suggests this emission is produced by normal star forming processes in photo-dissociation regions (PDRs), albeit on a galaxy wide scale fueled by cold-flow accretion. However, we could not fully exclude other mechanisms accounting for some or all of the emission. The work presented here, combining the CO emission with the [CII] 158 micron line, is consistent with PDRs being the source of the extreme C+ emission. It is further evidence for the existence of gas-rich galaxies in the early Universe undergoing galaxy-wide starbursts. These systems are not present in the nearby Universe, so represent a unique yet import evolutionary stage at early epochs.

  9. Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions.

    PubMed

    Nakamura, Nobuyuki; Kavanagh, Anthony P; Watanabe, Hirofumi; Sakaue, Hiroyuki A; Li, Yueming; Kato, Daiji; Currell, Fred J; Ohtani, Shunsuke

    2008-02-22

    Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).

  10. Strong expectations cancel locality effects: evidence from Hindi.

    PubMed

    Husain, Samar; Vasishth, Shravan; Srinivasan, Narayanan

    2014-01-01

    Expectation-driven facilitation (Hale, 2001; Levy, 2008) and locality-driven retrieval difficulty (Gibson, 1998, 2000; Lewis & Vasishth, 2005) are widely recognized to be two critical factors in incremental sentence processing; there is accumulating evidence that both can influence processing difficulty. However, it is unclear whether and how expectations and memory interact. We first confirm a key prediction of the expectation account: a Hindi self-paced reading study shows that when an expectation for an upcoming part of speech is dashed, building a rarer structure consumes more processing time than building a less rare structure. This is a strong validation of the expectation-based account. In a second study, we show that when expectation is strong, i.e., when a particular verb is predicted, strong facilitation effects are seen when the appearance of the verb is delayed; however, when expectation is weak, i.e., when only the part of speech "verb" is predicted but a particular verb is not predicted, the facilitation disappears and a tendency towards a locality effect is seen. The interaction seen between expectation strength and distance shows that strong expectations cancel locality effects, and that weak expectations allow locality effects to emerge.

  11. Strong Expectations Cancel Locality Effects: Evidence from Hindi

    PubMed Central

    Husain, Samar; Vasishth, Shravan; Srinivasan, Narayanan

    2014-01-01

    Expectation-driven facilitation (Hale, 2001; Levy, 2008) and locality-driven retrieval difficulty (Gibson, 1998, 2000; Lewis & Vasishth, 2005) are widely recognized to be two critical factors in incremental sentence processing; there is accumulating evidence that both can influence processing difficulty. However, it is unclear whether and how expectations and memory interact. We first confirm a key prediction of the expectation account: a Hindi self-paced reading study shows that when an expectation for an upcoming part of speech is dashed, building a rarer structure consumes more processing time than building a less rare structure. This is a strong validation of the expectation-based account. In a second study, we show that when expectation is strong, i.e., when a particular verb is predicted, strong facilitation effects are seen when the appearance of the verb is delayed; however, when expectation is weak, i.e., when only the part of speech “verb” is predicted but a particular verb is not predicted, the facilitation disappears and a tendency towards a locality effect is seen. The interaction seen between expectation strength and distance shows that strong expectations cancel locality effects, and that weak expectations allow locality effects to emerge. PMID:25010700

  12. Strong motion observations and recordings from the great Wenchuan Earthquake

    USGS Publications Warehouse

    Li, X.; Zhou, Z.; Yu, H.; Wen, R.; Lu, D.; Huang, M.; Zhou, Y.; Cu, J.

    2008-01-01

    The National Strong Motion Observation Network System (NSMONS) of China is briefly introduced in this paper. The NSMONS consists of permanent free-field stations, special observation arrays, mobile observatories and a network management system. During the Wenchuan Earthquake, over 1,400 components of acceleration records were obtained from 460 permanent free-field stations and three arrays for topographical effect and structural response observation in the network system from the main shock, and over 20,000 components of acceleration records from strong aftershocks occurred before August 1, 2008 were also obtained by permanent free-field stations of the NSMONS and 59 mobile instruments quickly deployed after the main shock. The strong motion recordings from the main shock and strong aftershocks are summarized in this paper. In the ground motion recordings, there are over 560 components with peak ground acceleration (PGA) over 10 Gal, the largest being 957.7 Gal. The largest PGA recorded during the aftershock exceeds 300 Gal. ?? 2008 Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag GmbH.

  13. Evidence of strong proton shape fluctuations from incoherent diffraction

    DOE PAGES

    Mantysaari, H.; Schenke, B.

    2016-07-25

    We show within the saturation framework that measurements of exclusive vector meson production at high energy provide evidence for strong geometric fluctuations of the proton. In comparison, the effect of saturation scale and color charge fluctuations is weak. This knowledge will allow detailed future measurements of the incoherent cross section to tightly constrain the fluctuating geometry of the proton as a function of the parton momentum fraction x.

  14. Near infrared observations of S155. evidence of induced star formation?

    NASA Astrophysics Data System (ADS)

    Hunt, L. K.; Lisi, F.; Felli, M.; Tofani, G.

    At the interface of the giant molecular cloud Cepheus OB3, S155 represents one of the most interesting examples of bright rim produced by the ionization of a nearby O-star. The interaction between the ionized HII region S155 and the hot molecular core Cepheus B may constitute the ideal site for new stars, according to the sequential star-formation theory. Past observations of molecular lines have shown the evidence of a hot spot in the cloud core, probably a compact region associated to a young stellar object. New J,H,K images recently obtained with the ARNICA array at the TIRGO telescope give evidence of stars with strong near-infrared excess, which must represent the newest generation of young stars.

  15. Evidence for CO in Jupiter's atmosphere from airborne spectroscopic observations at 5 microns

    NASA Technical Reports Server (NTRS)

    Larson, H. P.; Fink, U.; Treffers, R. R.

    1978-01-01

    High-altitude (12.4 km) spectra of Jupiter recorded at the Kuiper Airborne Observatory are analyzed for the presence of CO absorption lines. A line-by-line comparison of Jupiter's spectrum with that of carbon monoxide is presented, as well as a correlation analysis that includes the influence of other gases present in Jupiter's atmosphere (CH4, NH3, H2O, PH3, and GeH4). The resulting evidence points strongly to the presence of carbon monoxide in Jupiter's atmosphere, thus strengthening Beer's evidence for it. Possible explanations for the existence and observability of Jovian CO, including convection from hotter, deeper layers or decomposition of organic molecules, are explored. A recent suggestion that the Jovian CO is restricted to stratospheric levels is not supported by the observations.

  16. Observational evidence for cloud cover enhancement over western European forests

    PubMed Central

    Teuling, Adriaan J.; Taylor, Christopher M.; Meirink, Jan Fokke; Melsen, Lieke A.; Miralles, Diego G.; van Heerwaarden, Chiel C.; Vautard, Robert; Stegehuis, Annemiek I.; Nabuurs, Gert-Jan; de Arellano, Jordi Vilà-Guerau

    2017-01-01

    Forests impact regional hydrology and climate directly by regulating water and heat fluxes. Indirect effects through cloud formation and precipitation can be important in facilitating continental-scale moisture recycling but are poorly understood at regional scales. In particular, the impact of temperate forest on clouds is largely unknown. Here we provide observational evidence for a strong increase in cloud cover over large forest regions in western Europe based on analysis of 10 years of 15 min resolution data from geostationary satellites. In addition, we show that widespread windthrow by cyclone Klaus in the Landes forest led to a significant decrease in local cloud cover in subsequent years. Strong cloud development along the downwind edges of larger forest areas are consistent with a forest-breeze mesoscale circulation. Our results highlight the need to include impacts on cloud formation when evaluating the water and climate services of temperate forests, in particular around densely populated areas. PMID:28074840

  17. Observational evidence for cloud cover enhancement over western European forests.

    PubMed

    Teuling, Adriaan J; Taylor, Christopher M; Meirink, Jan Fokke; Melsen, Lieke A; Miralles, Diego G; van Heerwaarden, Chiel C; Vautard, Robert; Stegehuis, Annemiek I; Nabuurs, Gert-Jan; de Arellano, Jordi Vilà-Guerau

    2017-01-11

    Forests impact regional hydrology and climate directly by regulating water and heat fluxes. Indirect effects through cloud formation and precipitation can be important in facilitating continental-scale moisture recycling but are poorly understood at regional scales. In particular, the impact of temperate forest on clouds is largely unknown. Here we provide observational evidence for a strong increase in cloud cover over large forest regions in western Europe based on analysis of 10 years of 15 min resolution data from geostationary satellites. In addition, we show that widespread windthrow by cyclone Klaus in the Landes forest led to a significant decrease in local cloud cover in subsequent years. Strong cloud development along the downwind edges of larger forest areas are consistent with a forest-breeze mesoscale circulation. Our results highlight the need to include impacts on cloud formation when evaluating the water and climate services of temperate forests, in particular around densely populated areas.

  18. Genetic Basis of Sjögren's Syndrome. How Strong is the Evidence?

    PubMed Central

    Anaya, Juan-Manuel; Delgado-Vega, Angélica María; Castiblanco, John

    2006-01-01

    Sjögren's syndrome (SS) is a late-onset chronic autoimmune disease (AID) affecting the exocrine glands, mainly the salivary and lachrymal. Genetic studies on twins with primary SS have not been performed, and only a few case reports describing twins have been published. The prevalence of primary SS in siblings has been estimated to be 0.09% while the reported general prevalence of the disease is approximately 0.1%. The observed aggregation of AIDs in families of patients with primary SS is nevertheless supportive for a genetic component in its etiology. In the absence of chromosomal regions identified by linkage studies, research has focused on candidate gene approaches (by biological plausibility) rather than on positional approaches. Ancestral haplotype 8.1 as well as TNF, IL10 and SSA1 loci have been consistently associated with the disease although they are not specific for SS. In this review, the genetic component of SS is discussed on the basis of three known observations: (a) age at onset and sex-dependent presentation, (b) familial clustering of the disease, and (c) dissection of the genetic component. Since there is no strong evidence for a specific genetic component in SS, a large international and collaborative study would be suitable to assess the genetics of this disorder. PMID:17162364

  19. Evidence against a strong thermal inversion in HD 209458b from high-dispersion spectroscopy

    NASA Astrophysics Data System (ADS)

    Schwarz, Henriette; Brogi, Matteo; de Kok, Remco; Birkby, Jayne; Snellen, Ignas

    2015-04-01

    Context. Broadband secondary-eclipse measurements of strongly irradiated hot Jupiters have indicated the existence of atmospheric thermal inversions, but their presence is difficult to determine from broadband measurements because of degeneracies between molecular abundances and temperature structure. Furthermore, the primary mechanisms that drive the inversion layers in hot-Jupiter atmospheres are unknown. This question cannot be answered without reliable identification of thermal inversions. Aims: We apply high-resolution (R = 100 000) infrared spectroscopy to probe the temperature-pressure profile of HD 209458b. This bright, transiting hot-Jupiter has long been considered the gold standard for a hot Jupiter with an inversion layer, but this has been challenged in recent publications. Methods: We observed the thermal dayside emission of HD 209458b with the CRyogenic Infra-Red Echelle Spectrograph (CRIRES) on the Very Large Telescope during three nights, targeting the carbon monoxide band at 2.3 μm. Thermal inversions give rise to emission features, which means that detecting emission lines in the planetary spectrum, as opposed to absorption lines, would be direct evidence of a region in which the temperature increases with altitude. Results: We do not detect any significant absorption or emission of CO in the dayside spectrum of HD 209458b, although cross-correlation with template spectra either with CO absorption lines or with weak emission at the core of the lines show a low-significance correlation signal with asignal - to - noiseratioof ~3-3.5. Models with strong CO emission lines show a weak anti-correlation with similar or lower significance levels. Furthermore, we found no evidence of absorption or emission from H2O at these wavelengths. Conclusions: The non-detection of CO in the dayside spectrum of HD 209458b is interesting in light of a previous CO detection in the transmission spectrum. That there is no signal indicates that HD 209458b either has a

  20. Simultaneous Multi-angle Observations of Strong Langmuir Turbulence at HAARP

    NASA Astrophysics Data System (ADS)

    Watanabe, Naomi; Golkowski, Mark; Sheerin, James P.; Watkins, Brenton J.

    2015-10-01

    We report results from a recent series of experiments employing the HF transmitter of the High Frequency Active Auroral Research Program (HAARP) to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. The Modular UHF Ionospheric Radar (MUIR) located at the HAARP facility is used as the primary diagnostic. Short pulse, low duty cycle experiments are used to avoid generation of artificial field-aligned irregularities and isolate ponderomotive plasma turbulence effects. The HF pump frequency is close to the 3rd gyro-harmonic frequency and the HF pointing angle and MUIR look angle are between the HF Spitze angle and Magnetic Zenith angle. Plasma line spectra measured simultaneously in different spots of the interaction region display differences dependent on the aspect angle of the HF pump beam in the boresight direction and the pointing angle of the MUIR diagnostic radar. Outshifted Plasma Lines, cascade, collapse, coexistence, spectra are observed in agreement with existing theory and simulation results of Strong Langmuir Turbulence in ionospheric interaction experiments. It is found that SLT at HAARP is most readily observed at a HF pointing angle of 11° and UHF observation angle of 15°, which is consistent with the magnetic zenith effect as documented in previous works and optimal orientation of the refracted HF electric field vector.

  1. NuSTAR Observations of the Black Hole GS 1354-645: Evidence of Rapid Black Hole Spin

    NASA Astrophysics Data System (ADS)

    El-Batal, A. M.; Miller, J. M.; Reynolds, M. T.; Boggs, S. E.; Chistensen, F. E.; Craig, W. W.; Fuerst, F.; Hailey, C. J.; Harrison, F. A.; Stern, D. K.; Tomsick, J.; Walton, D. J.; Zhang, W. W.

    2016-07-01

    We present the results of a NuSTAR study of the dynamically confirmed stellar-mass black hole GS 1354-645. The source was observed during its 2015 “hard” state outburst; we concentrate on spectra from two relatively bright phases. In the higher-flux observation, the broadband NuSTAR spectra reveal a clear, strong disk reflection spectrum, blurred by a degree that requires a black hole spin of a={cJ}/{{GM}}2≥slant 0.98 (1σ statistical limits only). The fits also require a high inclination: θ ≃ 75{(2)}\\circ . Strong “dips” are sometimes observed in the X-ray light curves of sources viewed at such an angle; these are absent, perhaps indicating that dips correspond to flared disk structures that only manifest at higher accretion rates. In the lower flux observation, there is evidence of radial truncation of the thin accretion disk. We discuss these results in the context of spin in stellar-mass black holes, and inner accretion flow geometries at moderate accretion rates.

  2. NuSTAR Observations of the Black Hole GS 1354-645: Evidence of Rapid Black Hole Spin

    NASA Technical Reports Server (NTRS)

    El-Batal, A. M.; Miller, J. M.; Reynolds, M. T.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Fuerst, F.; Hailey, C. J.; Harrison, F. A.; Stern, D. K.; hide

    2016-01-01

    We present the results of a NuSTAR study of the dynamically confirmed stellar-mass black hole GS 1354-645. The source was observed during its 2015 "hard" state outburst; we concentrate on spectra from two relatively bright phases. In the higher-flux observation, the broadband NuSTAR spectra reveal a clear, strong disk reflection spectrum, blurred by a degree that requires a black hole spin of a = cJ/ GM(sup 2) > or = 0.98 (1(sigma) statistical limits only). The fits also require a high inclination: theta approx. = 75(2)deg. Strong "dips" are sometimes observed in the X-ray light curves of sources viewed at such an angle; these are absent, perhaps indicating that dips correspond to flared disk structures that only manifest at higher accretion rates. In the lower flux observation, there is evidence of radial truncation of the thin accretion disk. We discuss these results in the context of spin in stellar-mass black holes, and inner accretion flow geometries at moderate accretion rates.

  3. Observation of universal strong orbital-dependent correlation effects in iron chalcogenides

    DOE PAGES

    Yi, M.; Liu, Z. -K.; Zhang, Y.; ...

    2015-07-23

    Establishing the appropriate theoretical framework for unconventional superconductivity in the iron-based materials requires correct understanding of both the electron correlation strength and the role of Fermi surfaces. This fundamental issue becomes especially relevant with the discovery of the iron chalcogenide superconductors. Here, we use angle-resolved photoemission spectroscopy to measure three representative iron chalcogenides, FeTe 0.56Se 0.44, monolayer FeSe grown on SrTiO 3 and K 0.76Fe 1.72Se 2. We show that these superconductors are all strongly correlated, with an orbital-selective strong renormalization in the dxy bands despite having drastically different Fermi surface topologies. Furthermore, raising temperature brings all three compounds frommore » a metallic state to a phase where the dxy orbital loses all spectral weight while other orbitals remain itinerant. As a result, these observations establish that iron chalcogenides display universal orbital-selective strong correlations that are insensitive to the Fermi surface topology, and are close to an orbital-selective Mott phase, hence placing strong constraints for theoretical understanding of iron-based superconductors.« less

  4. Observation of universal strong orbital-dependent correlation effects in iron chalcogenides

    PubMed Central

    Yi, M.; Liu, Z-K; Zhang, Y.; Yu, R.; Zhu, J.-X.; Lee, J.J.; Moore, R.G.; Schmitt, F.T.; Li, W.; Riggs, S.C.; Chu, J.-H.; Lv, B.; Hu, J.; Hashimoto, M.; Mo, S.-K.; Hussain, Z.; Mao, Z.Q.; Chu, C.W.; Fisher, I.R.; Si, Q.; Shen, Z.-X.; Lu, D.H.

    2015-01-01

    Establishing the appropriate theoretical framework for unconventional superconductivity in the iron-based materials requires correct understanding of both the electron correlation strength and the role of Fermi surfaces. This fundamental issue becomes especially relevant with the discovery of the iron chalcogenide superconductors. Here, we use angle-resolved photoemission spectroscopy to measure three representative iron chalcogenides, FeTe0.56Se0.44, monolayer FeSe grown on SrTiO3 and K0.76Fe1.72Se2. We show that these superconductors are all strongly correlated, with an orbital-selective strong renormalization in the dxy bands despite having drastically different Fermi surface topologies. Furthermore, raising temperature brings all three compounds from a metallic state to a phase where the dxy orbital loses all spectral weight while other orbitals remain itinerant. These observations establish that iron chalcogenides display universal orbital-selective strong correlations that are insensitive to the Fermi surface topology, and are close to an orbital-selective Mott phase, hence placing strong constraints for theoretical understanding of iron-based superconductors. PMID:26204461

  5. Renewal of K-NET (National Strong-motion Observation Network of Japan)

    NASA Astrophysics Data System (ADS)

    Kunugi, T.; Fujiwara, H.; Aoi, S.; Adachi, S.

    2004-12-01

    The National Research Institute for Earth Science and Disaster Prevention (NIED) operates K-NET (Kyoshin Network), the national strong-motion observation network, which evenly covers the whole of Japan at intervals of 25 km on average. K-NET was constructed after the Hyogoken-Nambu (Kobe) earthquake in January 1995, and began operation in June 1996. Thus, eight years have passed since K-NET started, and large amounts of strong-motion records have been obtained. As technology has progressed and new technologies have become available, NIED has developed a new K-NET with improved functionality. New seismographs have been installed at 443 observatories mainly in southwestern Japan where there is a risk of strong-motion due to the Nankai and Tonankai earthquakes. The new system went into operation in June 2004, although seismographs have still to be replaced in other areas. The new seismograph (K-NET02) consists of a sensor module, a measurement module and a communication module. A UPS, a GPS antenna and a dial-up router are also installed together with a K-NET02. A triaxial accelerometer, FBA-ES-DECK (Kinemetrics Inc.) is built into the sensor module. The measurement module functions as a conventional strong-motion seismograph for high-precision observation. The communication module can perform sophisticated processes, such as calculation of the Japan Meteorological Agency (JMA) seismic intensity, continuous recording of data and near real-time data transmission. It connects to the Data Management Center (DMC) using an ISDN line. In case of a power failure, the measurement module can control the power supply to the router and the communication module to conserve battery power. One of the main features of K-NET02 is a function for processing JMA seismic intensity. K-NET02 functions as a proper seismic intensity meter that complies with the official requirements of JMA, although the old strong-motion seismograph (K-NET95) does not calculate seismic intensity. Another

  6. Mariner 9 observations of the south polar cap of Mars - Evidence for residual CO2 frost

    NASA Technical Reports Server (NTRS)

    Paige, D. A.; Herkenhoff, K. E.; Murray, B. C.

    1990-01-01

    The first spacecraft observations of the south residual polar cap of Mars were obtained by the Mariner 9 orbiter during the Martian southern summer season, 1971-1972. Analyses of Viking orbiter observations obtained 3 Mars years later have shown that residual carbon dioxide frost was present at the south polar cap in 1977. In this study, Mariner 9 infrared interferometer spectrometer spectra and television camera images are used in conjuction with multispectral thermal emission models to constrain the temperatures of dark bare ground and bright frost regions within the south residual cap. The results provide strong evidence that carbon dioxide frost was present throughout the summer season despite the fact that the residual frost deposits observed by Mariner 9 were less extensive than those observed by Viking.

  7. A bias-adjusted evidence synthesis of RCT and observational data: the case of total hip replacement.

    PubMed

    Schnell-Inderst, Petra; Iglesias, Cynthia P; Arvandi, Marjan; Ciani, Oriana; Matteucci Gothe, Raffaella; Peters, Jaime; Blom, Ashley W; Taylor, Rod S; Siebert, Uwe

    2017-02-01

    Evaluation of clinical effectiveness of medical devices differs in some aspects from the evaluation of pharmaceuticals. One of the main challenges identified is lack of robust evidence and a will to make use of experimental and observational studies (OSs) in quantitative evidence synthesis accounting for internal and external biases. Using a case study of total hip replacement to compare the risk of revision of cemented and uncemented implant fixation modalities, we pooled treatment effect estimates from OS and RCTs, and simplified existing methods for bias-adjusted evidence synthesis to enhance practical application. We performed an elicitation exercise using methodological and clinical experts to determine the strength of beliefs about the magnitude of internal and external bias affecting estimates of treatment effect. We incorporated the bias-adjusted treatment effects into a generalized evidence synthesis, calculating both frequentist and Bayesian statistical models. We estimated relative risks as summary effect estimates with 95% confidence/credibility intervals to capture uncertainty. When we compared alternative approaches to synthesizing evidence, we found that the pooled effect size strongly depended on the inclusion of observational data as well as on the use bias-adjusted estimates. We demonstrated the feasibility of using observational studies in meta-analyses to complement RCTs and incorporate evidence from a wider spectrum of clinically relevant studies and healthcare settings. To ensure internal validity, OS data require sufficient correction for confounding and selection bias, either through study design and primary analysis, or by applying post-hoc bias adjustments to the results. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd.

  8. Strong Bayesian evidence for the normal neutrino hierarchy

    NASA Astrophysics Data System (ADS)

    Simpson, Fergus; Jimenez, Raul; Pena-Garay, Carlos; Verde, Licia

    2017-06-01

    The configuration of the three neutrino masses can take two forms, known as the normal and inverted hierarchies. We compute the Bayesian evidence associated with these two hierarchies. Previous studies found a mild preference for the normal hierarchy, and this was driven by the asymmetric manner in which cosmological data has confined the available parameter space. Here we identify the presence of a second asymmetry, which is imposed by data from neutrino oscillations. By combining constraints on the squared-mass splittings [1] with the limit on the sum of neutrino masses of Σmν < 0.13 eV [2], and using a minimally informative prior on the masses, we infer odds of 42:1 in favour of the normal hierarchy, which is classified as "strong" in the Jeffreys' scale. We explore how these odds may evolve in light of higher precision cosmological data, and discuss the implications of this finding with regards to the nature of neutrinos. Finally the individual masses are inferred to be m1=3.80+26.2-3.73meV; m2=8.8+18-1.2meV; m3=50.4+5.8-1.2meV (95% credible intervals).

  9. Observations of height-dependent pressure-perturbation structure of a strong mesoscale gravity wave

    NASA Technical Reports Server (NTRS)

    Starr, David O'C.; Korb, C. L.; Schwemmer, Geary K.; Weng, Chi Y.

    1992-01-01

    Airborne observations using a downward-looking, dual-frequency, near-infrared, differential absorption lidar system provide the first measurements of the height-dependent pressure-perturbation field associated with a strong mesoscale gravity wave. A pressure-perturbation amplitude of 3.5 mb was measured within the lowest 1.6 km of the atmosphere over a 52-km flight line. Corresponding vertical displacements of 250-500 m were inferred from lidar-observed displacement of aerosol layers. Accounting for probable wave orientation, a horizontal wavelength of about 40 km was estimated. Satellite observations reveal wave structure of a comparable scale in concurrent cirrus cloud fields over an extended area. Smaller-scale waves were also observed. Local meteorological soundings are analyzed to confirm the existence of a suitable wave duct. Potential wave-generation mechanisms are examined and discussed. The large pressure-perturbation wave is attributed to rapid amplification or possible wave breaking of a gravity wave as it propagated offshore and interacted with a very stable marine boundary layer capped by a strong shear layer.

  10. Bayesian evidences for dark energy models in light of current observational data

    NASA Astrophysics Data System (ADS)

    Lonappan, Anto. I.; Kumar, Sumit; Ruchika; Dinda, Bikash R.; Sen, Anjan A.

    2018-02-01

    We do a comprehensive study of the Bayesian evidences for a large number of dark energy models using a combination of latest cosmological data from SNIa, CMB, BAO, strong lensing time delay, growth measurements, measurements of Hubble parameter at different redshifts and measurements of angular diameter distance by Megamaser Cosmology Project. We consider a variety of scalar field models with different potentials as well as different parametrizations for the dark energy equation of state. Among 21 models that we consider in our study, we do not find strong evidences in favor of any evolving dark energy model compared to Λ CDM . For the evolving dark energy models, we show that purely nonphantom models have much better evidences compared to those models that allow both phantom and nonphantom behaviors. Canonical scalar field with exponential and tachyon field with square potential have highest evidences among all the models considered in this work. We also show that a combination of low redshift measurements decisively favors an accelerating Λ CDM model compared to a nonaccelerating power law model.

  11. Observation, Sherlock Holmes, and Evidence Based Medicine.

    PubMed

    Osborn, John

    2002-01-01

    Sir Arthur Conan Doyle, the creator of the fictional detective Sherlock Holmes, studied medicine at the University of Edinburgh between 1876 and 1881 under Doctor Joseph Bell who emphasised in his teaching the importance of observation, deduction and evidence. Sherlock Holmes was modelled on Joseph Bell. The modern notions of Evidence Based Medicine (EBM) are not new. A very brief indication of some of the history of EBM is presented including a discussion of the important and usually overlooked contribution of statisticians to the Popperian philosophy of EBM.

  12. Observation of the ankle and evidence for a high-energy break in the cosmic ray spectrum

    NASA Astrophysics Data System (ADS)

    Abbasi, R.; Abuzayyad, T.; Amman, J.; Archbold, G.; Atkins, R.; Bellido, J.; Belov, K.; Belz, J.; Benzvi, S.; Bergman, D.

    2005-07-01

    We have measured the cosmic ray spectrum at energies above $10^{17}$ eV using the two air fluorescence detectors of the High Resolution Fly's Eye experiment operating in monocular mode. We describe the detector, PMT and atmospheric calibrations, and the analysis techniques for the two detectors. We fit the spectrum to models describing galactic and extragalactic sources. Our measured spectrum gives an observation of a feature known as the ``ankle'' near $3\\times 10^{18}$ eV, and strong evidence for a suppression near $6\\times 10^{19}$ eV.

  13. How strong is the evidence that solar ultraviolet B and vitamin D reduce the risk of cancer?: An examination using Hill's criteria for causality.

    PubMed

    Grant, William B

    2009-01-01

    The ultraviolet-B (UVB)-vitamin D-cancer hypothesis was proposed in 1980. Since then, several ecological and observational studies have examined the hypothesis, in addition to one good randomized, controlled trial. Also, the mechanisms whereby vitamin D reduces the risk of cancer have been elucidated. This report aims to examine the evidence to date with respect to the criteria for causality in a biological system first proposed by Robert Koch and later systematized by A. Bradford Hill. The criteria of most relevance are strength of association, consistency, biological gradient, plausibility/mechanisms and experimental verification. Results for several cancers generally satisfy these criteria. Results for breast and colorectal cancer satisfy the criteria best, but there is also good evidence that other cancers do as well, including bladder, esophageal, gallbladder, gastric, ovarian, rectal, renal and uterine corpus cancer, as well as Hodgkin's and non-Hodgkin's lymphoma. Several cancers have mixed findings with respect to UVB and/or vitamin D, including pancreatic and prostate cancer and melanoma. Even for these, the benefit of vitamin D seems reasonably strong. Although ecological and observational studies are not generally regarded as able to provide convincing evidence of causality, the fact that humanity has always existed with vitamin D from solar UVB irradiance means that there is a wealth of evidence to be harvested using the ecological and observational approaches. Nonetheless, additional randomized, controlled trials are warranted to further examine the link between vitamin D and cancer incidence, survival and mortality.

  14. Observational Evidence for Enhanced Greenhouse Effect Reinforcing Wintertime Arctic Amplification and Sea Ice Melting Onset

    NASA Astrophysics Data System (ADS)

    Cao, Y.; Liang, S.

    2017-12-01

    Despite an apparent hiatus in global warming, the Arctic climate continues to experience unprecedented changes. Summer sea ice is retreating at an accelerated rate, and surface temperatures in this region are rising at a rate double that of the global average, a phenomenon known as Arctic amplification. Although a lot of efforts have been made, the causes this unprecedented phenomenon remain unclear and are subjects of considerable debate. In this study, we report strong observational evidence, for the first time from long-term (1984-2014) spatially complete satellite records, that increased cloudiness and atmospheric water vapor in winter and spring have caused an extraordinary downward longwave radiative flux to the ice surface, which may then amplify the Arctic wintertime ice-surface warming. In addition, we also provide observed evidence that it is quite likely the enhancement of the wintertime greenhouse effect caused by water vapor and cloudiness has advanced the time of onset of ice melting in mid-May through inhibiting sea-ice refreezing in the winter and accelerating the pre-melting process in the spring, and in turn triggered the positive sea-ice albedo feedback process and accelerated the sea ice melting in the summer.

  15. Observation of dust acoustic shock wave in a strongly coupled dusty plasma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sharma, Sumita K., E-mail: sumita-sharma82@yahoo.com; Boruah, A.; Nakamura, Y.

    2016-05-15

    Dust acoustic shock wave is observed in a strongly coupled laboratory dusty plasma. A supersonic flow of charged microparticles is allowed to perturb a stationary dust fluid to excite dust acoustic shock wave. The evolution process beginning with steepening of initial wave front and then formation of a stable shock structure is similar to the numerical results of the Korteweg-de Vries-Burgers equation. The measured Mach number of the observed shock wave agrees with the theoretical results. Reduction of shock amplitude at large distances is also observed due to the dust neutral collision and viscosity effects. The dispersion relation and themore » spatial damping of a linear dust acoustic wave are also measured and compared with the relevant theory.« less

  16. Equatorial magnetic Rossby waves — evidence for a thin, strongly-buoyant stratified layer in earth's core

    NASA Astrophysics Data System (ADS)

    Knezek, Nicholas; Buffett, Bruce

    2017-04-01

    A low density stratified layer at the top of Earth's core has been proposed by many authors on the basis of chemical and thermodynamic arguments and has implications for Earth's thermal history, core energetics, and core-mantle interactions. Past studies claiming to detect a layer using perturbations in seismic wave speeds are contentious due to the extremely small magnitude of the detected signal. Recently, several studies have instead argued for the existence of a stratified layer by hypothesizing that oscillations in the observed geomagnetic field arise from waves propagating in the layer. In particular, 60 year oscillations in dipole strength have been attributed to global MAC waves, and 8 year oscillations of secular acceleration have been attributed to equatorially-trapped waves. We use a new hybrid finite-volume and Fourier numerical method we developed to model magnetohydrodynamic waves in a thin layer and show that a thin, strongly buoyant layer can produce equatorially-trapped waves with similar structures and periods to the observed 8 year signal. Using these simulated wave structures, we provide additional evidence for the existence of several propagating wave modes and place constraints on estimates for the wave periods, stratified layer thickness, and strength of buoyancy within the layer.

  17. Hydrodynamics in a Degenerate, Strongly Attractive Fermi Gas

    NASA Technical Reports Server (NTRS)

    Thomas, John E.; Kinast, Joseph; Hemmer, Staci; Turlapov, Andrey; O'Hara, Ken; Gehm, Mike; Granade, Stephen

    2004-01-01

    In summary, we use all-optical methods with evaporative cooling near a Feshbach resonance to produce a strongly interacting degenerate Fermi gas. We observe hydrodynamic behavior in the expansion dynamics. At low temperatures, collisions may not explain the expansion dynamics. We observe hydrodynamics in the trapped gas. Our observations include collisionally-damped excitation spectra at high temperature which were not discussed above. In addition, we observe weakly damped breathing modes at low temperature. The observed temperature dependence of the damping time and hydrodynamic frequency are not consistent with collisional dynamics nor with collisionless mean field interactions. These observations constitute the first evidence for superfluid hydrodynamics in a Fermi gas.

  18. Observational Evidence for Desert Amplification Using Multiple Satellite Datasets.

    PubMed

    Wei, Nan; Zhou, Liming; Dai, Yongjiu; Xia, Geng; Hua, Wenjian

    2017-05-17

    Desert amplification identified in recent studies has large uncertainties due to data paucity over remote deserts. Here we present observational evidence using multiple satellite-derived datasets that desert amplification is a real large-scale pattern of warming mode in near surface and low-tropospheric temperatures. Trend analyses of three long-term temperature products consistently confirm that near-surface warming is generally strongest over the driest climate regions and this spatial pattern of warming maximizes near the surface, gradually decays with height, and disappears in the upper troposphere. Short-term anomaly analyses show a strong spatial and temporal coupling of changes in temperatures, water vapor and downward longwave radiation (DLR), indicating that the large increase in DLR drives primarily near surface warming and is tightly associated with increasing water vapor over deserts. Atmospheric soundings of temperature and water vapor anomalies support the results of the long-term temperature trend analysis and suggest that desert amplification is due to comparable warming and moistening effects of the troposphere. Likely, desert amplification results from the strongest water vapor feedbacks near the surface over the driest deserts, where the air is very sensitive to changes in water vapor and thus efficient in enhancing the longwave greenhouse effect in a warming climate.

  19. SEARCHING FOR COOLING SIGNATURES IN STRONG LENSING GALAXY CLUSTERS: EVIDENCE AGAINST BARYONS SHAPING THE MATTER DISTRIBUTION IN CLUSTER CORES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Blanchard, Peter K.; Bayliss, Matthew B.; McDonald, Michael

    2013-07-20

    The process by which the mass density profile of certain galaxy clusters becomes centrally concentrated enough to produce high strong lensing (SL) cross-sections is not well understood. It has been suggested that the baryonic condensation of the intracluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. In this work, we search for evidence of ongoing ICM cooling in the first large, well-defined sample of SL selected galaxy clusters in the range 0.1 < z < 0.6. Based on known correlations between the ICM cooling rate and both optical emission line luminositymore » and star formation, we measure, for a sample of 89 SL clusters, the fraction of clusters that have [O II]{lambda}{lambda}3727 emission in their brightest cluster galaxy (BCG). We find that the fraction of line-emitting BCGs is constant as a function of redshift for z > 0.2 and shows no statistically significant deviation from the total cluster population. Specific star formation rates, as traced by the strength of the 4000 A break, D{sub 4000}, are also consistent with the general cluster population. Finally, we use optical imaging of the SL clusters to measure the angular separation, R{sub arc}, between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [O II] emission and D{sub 4000} as a function of R{sub arc}, a proxy observable for SL cross-sections. D{sub 4000} is constant with all values of R{sub arc}, and the [O II] emission fractions show no dependence on R{sub arc} for R{sub arc} > 10'' and only very marginal evidence of increased weak [O II] emission for systems with R{sub arc} < 10''. These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in SL cross-sections.« less

  20. Observational Evidence for Tidal Interaction in Close Binary Systems

    NASA Astrophysics Data System (ADS)

    Mazeh, T.

    This paper reviews the rich corpus of observational evidence for tidal effects, mostly based on photometric and radial-velocity measurements. This is done in a period when the study of binaries is being revolutionized by large-scaled photometric surveys that are detecting many thousands of new binaries and tens of extrasolar planets. We begin by examining the short-term effects, such as ellipsoidal variability and apsidal motion. We next turn to the long-term effects, of which circularization was studied the most: a transition period between circular and eccentric orbits has been derived for eight coeval samples of binaries. The study of synchronization and spin-orbit alignment is less advanced. As binaries are supposed to reach synchronization before circularization, one can expect finding eccentric binaries in pseudo-synchronization state, the evidence for which is reviewed. We also discuss synchronization in PMS and young stars, and compare the emerging timescale with the circularization timescale. We next examine the tidal interaction in close binaries that are orbited by a third distant companion, and review the effect of pumping the binary eccentricity by the third star. We elaborate on the impact of the pumped eccentricity on the tidal evolution of close binaries residing in triple systems, which may shrink the binary separation. Finally we consider the extrasolar planets and the observational evidence for tidal interaction with their parent stars. This includes a mechanism that can induce radial drift of short-period planets, either inward or outward, depending on the planetary radial position relative to the corotation radius. Another effect is the circularization of planetary orbits, the evidence for which can be found in eccentricity-versus-period plot of the planets already known. Whenever possible, the paper attempts to address the possible confrontation between theory and observations, and to point out noteworthy cases and observations that can be

  1. Strong motions observed by K-NET and KiK-net during the 2016 Kumamoto earthquake sequence

    NASA Astrophysics Data System (ADS)

    Suzuki, Wataru; Aoi, Shin; Kunugi, Takashi; Kubo, Hisahiko; Morikawa, Nobuyuki; Nakamura, Hiromitsu; Kimura, Takeshi; Fujiwara, Hiroyuki

    2017-01-01

    The nationwide strong-motion seismograph network of K-NET and KiK-net in Japan successfully recorded the strong ground motions of the 2016 Kumamoto earthquake sequence, which show the several notable characteristics. For the first large earthquake with a JMA magnitude of 6.5 (21:26, April 14, 2016, JST), the large strong motions are concentrated near the epicenter and the strong-motion attenuations are well predicted by the empirical relation for crustal earthquakes with a moment magnitude of 6.1. For the largest earthquake of the sequence with a JMA magnitude of 7.3 (01:25, April 16, 2016, JST), the large peak ground accelerations and velocities extend from the epicentral area to the northeast direction. The attenuation feature of peak ground accelerations generally follows the empirical relation, whereas that for velocities deviates from the empirical relation for stations with the epicentral distance of greater than 200 km, which can be attributed to the large Love wave having a dominant period around 10 s. The large accelerations were observed at stations even in Oita region, more than 70 km northeast from the epicenter. They are attributed to the local induced earthquake in Oita region, whose moment magnitude is estimated to be 5.5 by matching the amplitudes of the corresponding phases with the empirical attenuation relation. The real-time strong-motion observation has a potential for contributing to the mitigation of the ongoing earthquake disasters. We test a methodology to forecast the regions to be exposed to the large shaking in real time, which has been developed based on the fact that the neighboring stations are already shaken, for the largest event of the Kumamoto earthquakes, and demonstrate that it is simple but effective to quickly make warning. We also shows that the interpolation of the strong motions in real time is feasible, which will be utilized for the real-time forecast of ground motions based on the observed shakings.[Figure not available

  2. The Lesson Observation On-Line (Evidence Portfolio) Platform

    ERIC Educational Resources Information Center

    Cooper, David G.

    2015-01-01

    At a time when teacher training is being moved to school-based programmes it is important to engage in a research-informed dialogue about creating more distinctive, and cost-effective 21st century models of teacher training. Three years ago I began feasibility field testing the Lesson Observation On-line (Evidence Portfolio) Platform [LOOP]…

  3. Observational Evidence for Atoms.

    ERIC Educational Resources Information Center

    Jones, Edwin R., Jr.; Childers, Richard L.

    1984-01-01

    Discusses the development of the concept of atomicity and some of the many which can be used to establish its validity. Chemical evidence, evidence from crystals, Faraday's law of electrolysis, and Avogadro's number are among the areas which show how the concept originally developed from a purely philosophical idea. (JN)

  4. Critical behavior in trapped strongly interacting Fermi gases

    NASA Astrophysics Data System (ADS)

    Taylor, E.

    2009-08-01

    We investigate the width of the Ginzburg critical region and experimental signatures of critical behavior in strongly interacting trapped Fermi gases close to unitarity, where the s -wave scattering length diverges. Despite the fact that the width of the critical region is of the order unity, evidence of critical behavior in the bulk thermodynamics of trapped gases is strongly suppressed by their inhomogeneity. The specific heat of a harmonically confined gas, for instance, is linear in the reduced temperature t=(T-Tc)/Tc above Tc . We also discuss the prospects of observing critical behavior in the local compressibility from measurements of the density profile.

  5. Geomorphological Evidence for Pervasive Ground Ice on Ceres from Dawn Observations of Craters and Flows.

    NASA Astrophysics Data System (ADS)

    Schmidt, B. E.; Chilton, H.; Hughson, K.; Scully, J. E. C.; Russell, C. T.; Sizemore, H. G.; Nathues, A.; Platz, T.; Bland, M. T.; Schenk, P.; Hiesinger, H.; Jaumann, R.; Byrne, S.; Schorghofer, N.; Ammannito, E.; Marchi, S.; O'Brien, D. P.; Sykes, M. V.; Le Corre, L.; Capria, M. T.; Reddy, V.; Raymond, C. A.; Mest, S. C.; Feldman, W. C.

    2015-12-01

    Five decades of observations of Ceres' albedo, surface composition, shape and density suggest that Ceres is comprised of both silicates and tens of percent of ice. Historical suggestions of surficial hydrated silicates and evidence for water emission, coupled with its bulk density of ~2100 kg/m3 and Dawn observations of young craters containing high albedo spots support this conclusion. We report geomorphological evidence from survey data demonstrating that evaporative and fluid-flow processes within silicate-ice mixtures are prevalent on Ceres, and indicate that its surface materials contain significant water ice. Here we highlight three classes of features that possess strong evidence for ground ice. First, ubiquitous scalloped and "breached" craters are characterized by mass wasting and by the recession of crater walls in asymmetric patterns; these appear analogous to scalloped terrain on Mars and protalus lobes formed by mass wasting in terrestrial glaciated regions. The degradation of crater walls appears to be responsible for the nearly complete removal of some craters, particularly at low latitudes. Second, several high latitude, high elevation craters feature lobed flows that emanate from cirque-shaped head walls and bear strikingly similar morphology to terrestrial rock glaciers. These similarities include lobate toes and indications of furrows and ridges consistent with ice-cored or ice-cemented material. Other lobed flows persist at the base of crater walls and mass wasting features. Many flow features evidently terminate at ramparts. Third, there are frequent irregular domes, peaks and mounds within crater floors that depart from traditional crater central peaks or peak complexes. In some cases the irregular domes show evidence for high albedo or activity, and thus given other evidence for ice, these could be due to local melt and extrusion via hydrologic gradients, forming domes similar to pingos. The global distribution of these classes of features

  6. Observational evidence of European summer weather patterns predictable from spring

    NASA Astrophysics Data System (ADS)

    Ossó, Albert; Sutton, Rowan; Shaffrey, Len; Dong, Buwen

    2018-01-01

    Forecasts of summer weather patterns months in advance would be of great value for a wide range of applications. However, seasonal dynamical model forecasts for European summers have very little skill, particularly for rainfall. It has not been clear whether this low skill reflects inherent unpredictability of summer weather or, alternatively, is a consequence of weaknesses in current forecast systems. Here we analyze atmosphere and ocean observations and identify evidence that a specific pattern of summertime atmospheric circulation––the summer East Atlantic (SEA) pattern––is predictable from the previous spring. An index of North Atlantic sea-surface temperatures in March–April can predict the SEA pattern in July–August with a cross-validated correlation skill above 0.6. Our analyses show that the sea-surface temperatures influence atmospheric circulation and the position of the jet stream over the North Atlantic. The SEA pattern has a particularly strong influence on rainfall in the British Isles, which we find can also be predicted months ahead with a significant skill of 0.56. Our results have immediate application to empirical forecasts of summer rainfall for the United Kingdom, Ireland, and northern France and also suggest that current dynamical model forecast systems have large potential for improvement.

  7. Observational Evidence of Magnetic Waves in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    McIntosh, Scott W.

    2012-03-01

    The observational evidence in supporting the presence of magnetic waves in the outer solar atmosphere is growing rapidly - we will discuss recent observations and place them in context with salient observations made in the past. While the clear delineation of these magnetic wave "modes" is unclear, much can be learned about the environment in which they originated and possibly how they are removed from the system from the observations. Their diagnostic power is, as yet, untapped and their energy content (both as a mechanical source for the heating of coronal material and acceleration of the solar wind) remains in question, but can be probed observationally - raising challenges for modeling efforts. We look forward to the IRIS mission by proposing some sample observing sequences to help resolve some of the zoological issues present in the literature.

  8. Observational Evidence for Mixing and Dust Condensation in Core-Collapse Supernovae

    NASA Technical Reports Server (NTRS)

    Wooden, Diane; Young, Richard E. (Technical Monitor)

    1997-01-01

    Recent findings of isotopic anomalies of Ca-44 (the decay product of Ti-44) and the enhanced ratio of Si-28/Si-30 in SiC grains X, TiC subgrains, and graphite dust grains within primitive meteorites provides strong evidence that these presolar grains came from core-collapse supernovae. The chemical composition of the presolar grains requires macroscopic mixing of newly nucleo-synthesized elements from explosive silicon burning at the innermost zone of the ejects to higher velocities where C exists and where C/O > 1 in either the outer edge of the oxygen zone or in the He-C zone. To date, the only core-collapse supernova observed to form dust is the brightest supernova of the past four centuries, SN1987A in the Large Magellanic Cloud. Observations of SN1987A confirm large scale macroscopic mixing occurs in the explosions of massive stars. Rayleigh-Taylor instabilities macroscopically mix most of the ejects into regions which are still chemically homogeneous and which cool with different time scales. Only small clumps in the ejects are microscopically mixed. Observations show that dust condensed in the ejects of SN1987A after approx.500 days in the Fe-rich gas. Neither silicates nor SiC grains were seen in the dust emission spectrum of SN1987A. SN1987A, the Rosetta Stone of core-collapse supernovae, shows that while the mixing required to explain presolar grains occurs, the rapid cooling of the Fe zone and the sustained high temperatures of the O-Si, O-C, and He-C zones favor the formation of iron-rich rather than oxygen- or carbon-rich grains.

  9. Formation of Globular Clusters with Internal Abundance Spreads in r-Process Elements: Strong Evidence for Prolonged Star Formation

    NASA Astrophysics Data System (ADS)

    Bekki, Kenji; Tsujimoto, Takuji

    2017-07-01

    Several globular clusters (GCs) in the Galaxy are observed to show internal abundance spreads in r-process elements (e.g., Eu). We propose a new scenario that explains the origin of these GCs (e.g., M5 and M15). In this scenario, stars with no/little abundance variations first form from a massive molecular cloud (MC). After all of the remaining gas of the MC is expelled by numerous supernovae, gas ejected from asymptotic giant branch stars can be accumulated in the central region of the GC to form a high-density intracluster medium (ICM). Merging of neutron stars then occurs to eject r-process elements, which can be efficiently trapped in and subsequently mixed with the ICM. New stars formed from the ICM can have r-process abundances that are quite different from those of earlier generations of stars within the GC. This scenario can explain both (I) why r-process elements can be trapped within GCs and (II) why GCs with internal abundance spreads in r-process elements do not show [Fe/H] spreads. Our model shows (I) that a large fraction of Eu-rich stars can be seen in Na-enhanced stellar populations of GCs, as observed in M15, and (II) why most of the Galactic GCs do not exhibit such internal abundance spreads. Our model demonstrates that the observed internal spreads of r-process elements in GCs provide strong evidence for prolonged star formation (˜108 yr).

  10. Observation and Simulation of Daytime Strong Winds on Northern Slopes of Himalayas, near Mount Everest

    NASA Astrophysics Data System (ADS)

    Fanglin, S.; Ma, Y.; Hu, Z.; Tartari, G.; Salerno, F.; Gerken, T.; Bonasoni, P.; Cristofanelli, P.; Vuillermoz, E.

    2017-12-01

    The seasonal variability of strong daytime winds in a northern Himalayan valley, and their relationship with the synoptic circulation was examined using in-situ meteorological data from 2006 and numerical simulations. Meteorological observations were focused on the downwind Rongbuk valley, on the northern side of the Himalayas (4270 m a.s.l.), where a wind profile radar was available. In 2006, strong daytime wind conditions during the non-monsoon and monsoon (May 21 through the earlier October) periods were characterized by strong southwesterly and southeasterly winds, respectively. Numerical simulations were performed to investigate the mechanism causing these daytime strong winds using the Weather Research and Forecast (WRF) model. We found that during the non-monsoon season, the strong winds are produced by downwards momentum transport from the westerly winds aloft, while those during the monsoon season are driven by the inflow into the Arun Valley east of Mt.Everest. The air in the Arun Valley is found colder than the air outside in daytime. This thermal difference between the air in Arun Valley and Repu Valley (including QOMS) can explain the formation of the strong daytime southeasterly wind at QOMS in monsoon season. While in non-monsoon, due to the westerly wind associated with the STJ, the colder air from Arun Valley is confined below the ridge.

  11. The Quake-Catcher Network: Improving Earthquake Strong Motion Observations Through Community Engagement

    NASA Astrophysics Data System (ADS)

    Cochran, E. S.; Lawrence, J. F.; Christensen, C. M.; Chung, A. I.; Neighbors, C.; Saltzman, J.

    2010-12-01

    The Quake-Catcher Network (QCN) involves the community in strong motion data collection by utilizing volunteer computing techniques and low-cost MEMS accelerometers. Volunteer computing provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. Micro-Electro-Mechanical Systems (MEMS) triaxial accelerometers can be attached to a desktop computer via USB and are internal to many laptops. Preliminary shake table tests show the MEMS accelerometers can record high-quality seismic data with instrument response similar to research-grade strong-motion sensors. QCN began distributing sensors and software to K-12 schools and the general public in April 2008 and has grown to roughly 1500 stations worldwide. We also recently tested whether sensors could be quickly deployed as part of a Rapid Aftershock Mobilization Program (RAMP) following the 2010 M8.8 Maule, Chile earthquake. Volunteers are recruited through media reports, web-based sensor request forms, as well as social networking sites. Using data collected to date, we examine whether a distributed sensing network can provide valuable seismic data for earthquake detection and characterization while promoting community participation in earthquake science. We utilize client-side triggering algorithms to determine when significant ground shaking occurs and this metadata is sent to the main QCN server. On average, trigger metadata are received within 1-10 seconds from the observation of a trigger; the larger data latencies are correlated with greater server-station distances. When triggers are detected, we determine if the triggers correlate to others in the network using spatial and temporal clustering of incoming trigger information. If a minimum number of triggers are detected then a QCN-event is declared and an initial earthquake location and magnitude is estimated. Initial analysis suggests that the estimated locations and magnitudes are

  12. Making and Recording Observations: When Done Well, Observations Can Serve as Evidence When Engaging in Science Practices

    ERIC Educational Resources Information Center

    Arias, Anna Maria; Davis, Elizabeth A.

    2016-01-01

    Making and recording scientific observations is a fundamental activity of the scientific community. Scientists use their senses and tools (e.g., magnifying glasses, rulers, colored pencils) to make records of the phenomena (e.g., light energy, ecosystems) they are investigating. These observations often serve as evidence in the scientific…

  13. Observational Evidence for the Causes and Consequences of Chromospheric Reconnection

    NASA Astrophysics Data System (ADS)

    Yan, Limei; He, Jiansen; Xia, Lidong; Jiao, Fangran

    2015-05-01

    The chromospheric anemone jets with an inverse “Y” shape are ubiquitous, as revealed by the Solar Optical Telescope observations. These jets are considered to be consequences of chromospheric magnetic reconnections. Although these jets have been studied intensively, the dynamics and their driving causes remain unclear observationally. In this work, we report a case of a chromospheric jet showing complete observational evidence for the cause and consequence of chromospheric intermittent reconnection. The intermittent eruption of this jet shows two distinct quasi-periods, 50-60 s and 600-700 s. The short-period eruptions may be related to the plasmoid-induced reconnection, and the long-period ones may be interpreted as sequences of cycles of energy storage and release during magnetic reconnections. The observations also reveal Alfvénic waves with a mean period around 88 s and a maximum transverse displacement around 0.″26. The jet is hosted by a loop moving smoothly with a horizontal speed of ˜0.4 km s-1. Our results provide observational evidence supporting the magnetic reconnection model of the formation of the chromospheric jets with related products, in which the loop advection drives intermittent magnetic reconnections, and the reconnection outflows carrying plasmoids collide further with the ambient field lines and finally excite waves and jets.

  14. High-latitude dayside electric fields and currents during strong northward interplanetary magnetic field - Observations and model simulation

    NASA Technical Reports Server (NTRS)

    Clauer, C. Robert; Friis-Christensen, Eigil

    1988-01-01

    On July 23, 1983 the IMF turned strongly northward, becoming about 22 nT for several hours. Using a combined data set of ionospheric convection measurements made by the Sondre Stromfjord incoherent scatter radar and convection inferred from Greenland magnetometer measurements, the onset of the reconfiguration of the high-latitude ionospheric currents is found to occur about 3 min after the northward IMF encounters the magnetopause. The large-scale reconfiguration of currents, however, appears to evolve over a period of about 22 min. These observations and the results of numerical simulations indicate that the dayside polar-cap electric field observed during strong northward IMF is produced by a direct electrical current coupling with the solar wind.

  15. Refined mapping of a gene responsible for Fukuyama-type congenital muscular dystrophy: Evidence for strong linkage disequilibrium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Toda, Tatsushi; Ikegawa, Shiro; Okui, Keiko

    1994-11-01

    Fukuyama-type congenital muscular dystrophy (FCMD), the second most common form of childhood muscular dystrophy in Japan, is an autosomal recessive severe muscular dystrophy associated with an anomaly of the brain. After our initial mapping of the FCMD locus to chromosome 9q31-33, we further defined the locus within a region of {approximately}5 cM between loci D9S127 and CA246, by homozygosity mapping in patients born to consanguineous marriages and by recombination analyses in other families. We also found evidence for strong linkage disequilibrium between FCMD and a polymorphic microsatellite marker, mfd220, which showed no recombination and a lod score of (Z) 17.49.more » A {open_quotes}111-bp{close_quotes} allele for the mfd220 was observed in 22 (34%) of 64 FCMD chromosomes, but it was present in only 1 of 120 normal chromosomes. This allelic association with FCMD was highly significant ({chi}{sup 2} = 50.7; P < .0001). Hence, we suspect that the FCMD gene could lie within a few hundred kilobases of the mfd220 locus. 32 refs., 2 figs., 2 tabs.« less

  16. Formation of Globular Clusters with Internal Abundance Spreads in r -Process Elements: Strong Evidence for Prolonged Star Formation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bekki, Kenji; Tsujimoto, Takuji

    Several globular clusters (GCs) in the Galaxy are observed to show internal abundance spreads in r -process elements (e.g., Eu). We propose a new scenario that explains the origin of these GCs (e.g., M5 and M15). In this scenario, stars with no/little abundance variations first form from a massive molecular cloud (MC). After all of the remaining gas of the MC is expelled by numerous supernovae, gas ejected from asymptotic giant branch stars can be accumulated in the central region of the GC to form a high-density intracluster medium (ICM). Merging of neutron stars then occurs to eject r -processmore » elements, which can be efficiently trapped in and subsequently mixed with the ICM. New stars formed from the ICM can have r -process abundances that are quite different from those of earlier generations of stars within the GC. This scenario can explain both (i) why r -process elements can be trapped within GCs and (ii) why GCs with internal abundance spreads in r -process elements do not show [Fe/H] spreads. Our model shows (i) that a large fraction of Eu-rich stars can be seen in Na-enhanced stellar populations of GCs, as observed in M15, and (ii) why most of the Galactic GCs do not exhibit such internal abundance spreads. Our model demonstrates that the observed internal spreads of r -process elements in GCs provide strong evidence for prolonged star formation (∼10{sup 8} yr).« less

  17. Observational Evidence of Impacts of Aerosols on Seasonal-to-Interannual Variability of the Asian Monsoon

    NASA Technical Reports Server (NTRS)

    Lau, K.-M.; Kim, K.-M.; Hsu, N. C.

    2006-01-01

    Observational evidences are presented showing that the Indian subcontinent and surrounding regions are subject to heavy loading of absorbing aerosols (dust and black carbon), with strong seasonality closely linked to the monsoon annual rainfall cycle. Increased loading of absorbing aerosols over the Indo-Gangetic Plain in April-May is associated with a) increased heating of the upper troposphere over the Tibetan Plateau, b) an advance of the monsoon rainy season, and c) subsequent enhancement of monsoon rainfall over the South Asia subcontinent, and reduction over East Asia. Also presented are radiative transfer calculations showing how differential solar absorption by aerosols over bright surface (desert or snow cover land) compared to dark surface (vegetated land and ocean), may be instrumental in triggering an aerosol-monsoon large-scale circulation and water cycle feedback, consistent with the elevated heat pump hypothesis (Lau et al. 2006).

  18. OBSERVATIONAL EVIDENCE FOR THE CAUSES AND CONSEQUENCES OF CHROMOSPHERIC RECONNECTION

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yan, Limei; Xia, Lidong; Jiao, Fangran

    The chromospheric anemone jets with an inverse “Y” shape are ubiquitous, as revealed by the Solar Optical Telescope observations. These jets are considered to be consequences of chromospheric magnetic reconnections. Although these jets have been studied intensively, the dynamics and their driving causes remain unclear observationally. In this work, we report a case of a chromospheric jet showing complete observational evidence for the cause and consequence of chromospheric intermittent reconnection. The intermittent eruption of this jet shows two distinct quasi-periods, 50–60 s and 600–700 s. The short-period eruptions may be related to the plasmoid-induced reconnection, and the long-period ones may bemore » interpreted as sequences of cycles of energy storage and release during magnetic reconnections. The observations also reveal Alfvénic waves with a mean period around 88 s and a maximum transverse displacement around 0.″26. The jet is hosted by a loop moving smoothly with a horizontal speed of ∼0.4 km s{sup −1}. Our results provide observational evidence supporting the magnetic reconnection model of the formation of the chromospheric jets with related products, in which the loop advection drives intermittent magnetic reconnections, and the reconnection outflows carrying plasmoids collide further with the ambient field lines and finally excite waves and jets.« less

  19. Observability of atomic line features in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Wunner, G.; Ruder, H.; Herold, H.; Truemper, J.

    1981-01-01

    The physical properties of atoms in superstrong magnetic fields, characteristic of neutron stars, and the possibility of detecting magnetically strongly shifted atomic lines in the spectra of magnetized X-ray pulsars are discussed. It is suggested that it is recommendable to look for magnetically strongly shifted Fe 26 Lyman lines in rotating neutron stars of not too high luminosity using spectrometers working in the energy range 10 - 20 keV, with sensitivities to minus 4 power photons per sq cm and second, and resolution E/delta E approx. 10-100.

  20. Strong RFI observed in protected 21 cm band at Zurich observatory, Switzerland

    NASA Astrophysics Data System (ADS)

    Monstein, C.

    2014-03-01

    While testing a new antenna control software tool, the telescope was moved to the most western azimuth position pointing to our own building. While de-accelerating the telescope, the spectrometer showed strong broadband radio frequency interference (RFI) and two single-frequency carriers around 1412 and 1425 MHz, both of which are in the internationally protected band. After lengthy analysis it was found out, that the Webcam AXIS2000 was the source for both the broadband and single-frequency interference. Switching off the Webcam solved the problem immediately. So, for future observations of 21 cm radiation, all nearby electronics has to be switched off. Not only the Webcam but also all unused PCs, printers, networks, monitors etc.

  1. Quadratic Fermi node in a 3D strongly correlated semimetal

    PubMed Central

    Kondo, Takeshi; Nakayama, M.; Chen, R.; Ishikawa, J. J.; Moon, E.-G.; Yamamoto, T.; Ota, Y.; Malaeb, W.; Kanai, H.; Nakashima, Y.; Ishida, Y.; Yoshida, R.; Yamamoto, H.; Matsunami, M.; Kimura, S.; Inami, N.; Ono, K.; Kumigashira, H.; Nakatsuji, S.; Balents, L.; Shin, S.

    2015-01-01

    Strong spin–orbit coupling fosters exotic electronic states such as topological insulators and superconductors, but the combination of strong spin–orbit and strong electron–electron interactions is just beginning to be understood. Central to this emerging area are the 5d transition metal iridium oxides. Here, in the pyrochlore iridate Pr2Ir2O7, we identify a non-trivial state with a single-point Fermi node protected by cubic and time-reversal symmetries, using a combination of angle-resolved photoemission spectroscopy and first-principles calculations. Owing to its quadratic dispersion, the unique coincidence of four degenerate states at the Fermi energy, and strong Coulomb interactions, non-Fermi liquid behaviour is predicted, for which we observe some evidence. Our discovery implies that Pr2Ir2O7 is a parent state that can be manipulated to produce other strongly correlated topological phases, such as topological Mott insulator, Weyl semimetal, and quantum spin and anomalous Hall states. PMID:26640114

  2. Quadratic Fermi node in a 3D strongly correlated semimetal

    DOE PAGES

    Kondo, Takeshi; Nakayama, M.; Chen, R.; ...

    2015-12-07

    We report that strong spin–orbit coupling fosters exotic electronic states such as topological insulators and superconductors, but the combination of strong spin–orbit and strong electron–electron interactions is just beginning to be understood. Central to this emerging area are the 5d transition metal iridium oxides. Here, in the pyrochlore iridate Pr 2Ir 2O 7, we identify a non-trivial state with a single-point Fermi node protected by cubic and time-reversal symmetries, using a combination of angle-resolved photoemission spectroscopy and first-principles calculations. Owing to its quadratic dispersion, the unique coincidence of four degenerate states at the Fermi energy, and strong Coulomb interactions, non-Fermimore » liquid behaviour is predicted, for which we observe some evidence. Lastly, our discovery implies that Pr 2Ir 2O 7 is a parent state that can be manipulated to produce other strongly correlated topological phases, such as topological Mott insulator, Weyl semimetal, and quantum spin and anomalous Hall states.« less

  3. ALMA observations of a metal-rich damped Lyα absorber at z = 2.5832: evidence for strong galactic winds in a galaxy group

    NASA Astrophysics Data System (ADS)

    Fynbo, J. P. U.; Heintz, K. E.; Neeleman, M.; Christensen, L.; Dessauges-Zavadsky, M.; Kanekar, N.; Møller, P.; Prochaska, J. X.; Rhodin, N. H. P.; Zwaan, M.

    2018-06-01

    We report on the results of a search for CO(3-2) emission from the galaxy counterpart of a high-metallicity Damped Lyα Absrober (DLA) at z = 2.5832 towards the quasar Q0918+1636. We do not detect CO emission from the previously identified DLA galaxy counterpart. The limit we infer on Mgas/M⋆ is in the low end of the range found for DLA galaxies, but is still consistent with what is found for other star-forming galaxies at similar redshifts. Instead we detect CO(3-2) emission from another intensely star-forming galaxy at an impact parameter of 117 kpc from the line-of-sight to the quasar and 131 km s-1 redshifted relative to the velocity centroid of the DLA in the quasar spectrum. In the velocity profile of the low- and high-ionisation absorption lines of the DLA there is an absorption component consistent with the redshift of this CO-emitting galaxy. It is plausible that this component is physically associated with a strong outflow in the plane of the sky from the CO-emitting galaxy. If true, this would be further evidence, in addition to what is already known from studies of Lyman-break galaxies, that galactic outflows can be traced beyond 100 kpc from star-forming galaxies. The case of this z = 2.583 structure is an illustration of this in a group environment.

  4. Strong-motion observations of the M 7.8 Gorkha, Nepal, earthquake sequence and development of the N-shake strong-motion network

    USGS Publications Warehouse

    Dixit, Amod; Ringler, Adam; Sumy, Danielle F.; Cochran, Elizabeth S.; Hough, Susan E.; Martin, Stacey; Gibbons, Steven; Luetgert, James H.; Galetzka, John; Shrestha, Surya; Rajaure, Sudhir; McNamara, Daniel E.

    2015-01-01

    We present and describe strong-motion data observations from the 2015 M 7.8 Gorkha, Nepal, earthquake sequence collected using existing and new Quake-Catcher Network (QCN) and U.S. Geological Survey NetQuakes sensors located in the Kathmandu Valley. A comparison of QCN data with waveforms recorded by a conventional strong-motion (NetQuakes) instrument validates the QCN data. We present preliminary analysis of spectral accelerations, and peak ground acceleration and velocity for earthquakes up to M 7.3 from the QCN stations, as well as preliminary analysis of the mainshock recording from the NetQuakes station. We show that mainshock peak accelerations were lower than expected and conclude the Kathmandu Valley experienced a pervasively nonlinear response during the mainshock. Phase picks from the QCN and NetQuakes data are also used to improve aftershock locations. This study confirms the utility of QCN instruments to contribute to ground-motion investigations and aftershock response in regions where conventional instrumentation and open-access seismic data are limited. Initial pilot installations of QCN instruments in 2014 are now being expanded to create the Nepal–Shaking Hazard Assessment for Kathmandu and its Environment (N-SHAKE) network.

  5. World Health Organization strong recommendations based on low-quality evidence (study quality) are frequent and often inconsistent with GRADE guidance.

    PubMed

    Alexander, Paul E; Brito, Juan P; Neumann, Ignacio; Gionfriddo, Michael R; Bero, Lisa; Djulbegovic, Benjamin; Stoltzfus, Rebecca; Montori, Victor M; Norris, Susan L; Schünemann, Holger J; Guyatt, Gordon H

    2016-04-01

    In 2007 the World Health Organization (WHO) adopted the GRADE system for development of public health guidelines. Previously we found that many strong recommendations issued by WHO are based on evidence for which there is only low or very low confidence in the estimates of effect (discordant recommendations). GRADE guidance indicates that such discordant recommendations are rarely appropriate but suggests five paradigmatic situations in which discordant recommendations may be warranted. We sought to provide insight into the many discordant recommendations in WHO guidelines. We examined all guidelines that used the GRADE method and were approved by the WHO Guideline Review Committee between 2007 and 2012. Teams of reviewers independently abstracted data from eligible guidelines and classified recommendations either into one of the five paradigms for appropriately-formulated discordant recommendations or into three additional categories in which discordant recommendations were inconsistent with GRADE guidance: 1) the evidence warranted moderate or high confidence (a misclassification of evidence) rather than low or very low confidence; 2) good practice statements; or 3) uncertainty in the estimates of effect would best lead to a conditional (weak) recommendation. The 33 eligible guidelines included 160 discordant recommendations, of which 98 (61.3%) addressed drug interventions and 132 (82.5%) provided some rationale (though not entirely explicit at times) for the strong recommendation. Of 160 discordant recommendations, 25 (15.6%) were judged consistent with one of the five paradigms for appropriate recommendations; 33 (21%) were based on evidence warranting moderate or high confidence in the estimates of effect; 29 (18%) were good practice statements; and 73 (46%) warranted a conditional, rather than a strong recommendation. WHO discordant recommendations are often inconsistent with GRADE guidance, possibly threatening the integrity of the process. Further training

  6. Hierarchy of evidence: where observational studies fit in and why we need them.

    PubMed

    Hoppe, Daniel J; Schemitsch, Emil H; Morshed, Saam; Tornetta, Paul; Bhandari, Mohit

    2009-05-01

    Although randomized controlled designs are considered the so-called gold standard in medical trials and sit atop the hierarchy of evidence in evidence-based medicine, there are situations in which they are impractical or unethical to undertake, especially in surgical trials. Then, observational studies often provide the best source of information. In this paper, we use examples from the literature to explain the importance of observational studies in furthering the boundaries of orthopaedic surgery and knowledge of musculoskeletal disorders.

  7. Evidence of redshifts in the average solar line profiles of C IV and Si IV from OSO-8 observations

    NASA Technical Reports Server (NTRS)

    Roussel-Dupre, D.; Shine, R. A.

    1982-01-01

    Line profiles of C IV and Si V obtained by the Colorado spectrometer on OSO-8 are presented. It is shown that the mean profiles are redshifted with a magnitude varying from 6-20 km/s, and with a mean of 12 km/s. An apparent average downflow of material in the 50,000-100,000 K temperature range is measured. The redshifts are observed in the line center positions of spatially and temporally averaged profiles and are measured either relative to chromospheric Si I lines or from a comparison of sun center and limb profiles. The observations of 6-20 km/s redshifts place constraints on the mechanisms that dominate EUV line emission since it requires a strong weighting of the emission in regions of downward moving material, and since there is little evidence for corresponding upward moving materials in these lines.

  8. Observation of Spin-Polarons in a strongly interacting Fermi liquid

    NASA Astrophysics Data System (ADS)

    Zwierlein, Martin

    2009-03-01

    We have observed spin-polarons in a highly imbalanced mixture of fermionic atoms using tomographic RF spectroscopy. Feshbach resonances allow to freely tune the interactions between the two spin states involved. A single spin down atom immersed in a Fermi sea of spin up atoms can do one of two things: For strong attraction, it can form a molecule with exactly one spin up partner, but for weaker interaction it will spread its attraction and surround itself with a collection of majority atoms. This spin down atom ``dressed'' with a spin up cloud constitutes the spin-polaron. We have observed a striking spectroscopic signature of this quasi-particle for various interaction strengths, a narrow peak in the spin down spectrum that emerges above a broad background. The narrow width signals a long lifetime of the spin-polaron, much longer than the collision rate with spin up atoms, as it must be for a proper quasi-particle. The peak position allows to directly measure the polaron energy. The broad pedestal at high energies reveals physics at short distances and is thus ``molecule-like'': It is exactly matched by the spin up spectra. The comparison with the area under the polaron peak allows to directly obtain the quasi-particle weight Z. We observe a smooth transition from polarons to molecules. At a critical interaction strength of 1/kFa = 0.7, the polaron peak vanishes and spin up and spin down spectra exactly match, signalling the formation of molecules. This is the same critical interaction strength found earlier to separate a normal Fermi mixture from a superfluid molecular Bose-Einstein condensate. The spin-polarons determine the low-temperature phase diagram of imbalanced Fermi mixtures. In principle, polarons can interact with each other and should, at low enough temperatures, form a superfluid of p-wave pairs. We will present a first indication for interactions between polarons.

  9. Observations of Strong Surface Radar Ducts over the Persian Gulf.

    NASA Astrophysics Data System (ADS)

    Brooks, Ian M.; Goroch, Andreas K.; Rogers, David P.

    1999-09-01

    Ducting of microwave radiation is a common phenomenon over the oceans. The height and strength of the duct are controlling factors for radar propagation and must be determined accurately to assess propagation ranges. A surface evaporation duct commonly forms due to the large gradient in specific humidity just above the sea surface; a deeper surface-based or elevated duct frequently is associated with the sudden change in temperature and humidity across the boundary layer inversion.In April 1996 the U.K. Meteorological Office C-130 Hercules research aircraft took part in the U.S. Navy Ship Antisubmarine Warfare Readiness/Effectiveness Measuring exercise (SHAREM-115) in the Persian Gulf by providing meteorological support and making measurements for the study of electromagnetic and electro-optical propagation. The boundary layer structure over the Gulf is influenced strongly by the surrounding desert landmass. Warm dry air flows from the desert over the cooler waters of the Gulf. Heat loss to the surface results in the formation of a stable internal boundary layer. The layer evolves continuously along wind, eventually forming a new marine atmospheric boundary layer. The stable stratification suppresses vertical mixing, trapping moisture within the layer and leading to an increase in refractive index and the formation of a strong boundary layer duct. A surface evaporation duct coexists with the boundary layer duct.In this paper the authors present aircraft- and ship-based observations of both the surface evaporation and boundary layer ducts. A series of sawtooth aircraft profiles map the boundary layer structure and provide spatially distributed estimates of the duct depth. The boundary layer duct is found to have considerable spatial variability in both depth and strength, and to evolve along wind over distances significant to naval operations (100 km). The depth of the evaporation duct is derived from a bulk parameterization based on Monin-Obukhov similarity theory

  10. Instrumental evidence of an unusually strong West African Monsoon in the 19th century

    NASA Astrophysics Data System (ADS)

    Gallego, David; Ordoñez, Paulina; Ribera, Pedro; Peña-Ortiz, Cristina; Garcia-Herrera, Ricardo; Vega, Inmaculada; Gomez, Francisco de Paula

    2016-04-01

    The precipitation in the Sahel -which is mainly controlled by the dynamics of the West African Monsoon-, has been in the spot of the climate community for the last three decades due to the persistence of the drought period that started in the 1970s. Unfortunately, reliable meteorological series in this area are only available since the beginning of the 20th Century, thus limiting our understanding of the significance of this period from a long term perspective. Currently, our knowledge of what happened in times previous to the 20th Century essentially relies in documentary or proxy sources. In this work, we present the first instrumental evidence of a 50 year-long period characterised by an unusually strong West African monsoon in the19th Century. Following the recent advances in the generation of climatic indices based on data from ship's logbooks, we used historical wind observations to compute a new index (the so-called ASWI) for characterising the strength of the West African Monsoon. The ASWI is based in the persistence of the southwesterly winds in the [29°W-17°W;7°N-13°N] area and it has been possible to compute it since 1790 for July and since 1839 for August and September. We show that the ASWI is a reliable measure of the monsoon's strength and the Sahelian rainfall. Our new series clearly shows the well-known drought period starting in the 1970s. During this dry period, the West African Monsoon was particularly weak and interestingly, we found that since then, the correlations with different climatic patterns such as the Pacific and Atlantic "El Niño" changed significantly in relation to those of the previous century. Remarkably, our results also show that the period 1839-1890 was characterised by an unusually strong and persistent monsoon. Notwithstanding, two of the few dry years within this period were concurrent with large volcanic eruptions in the Northern Hemisphere. This latter result supports the recently suggested relationship between major

  11. Inclination Angles of Black Hole X-Ray Binaries Manifest Strong Gravity around Black Holes

    NASA Technical Reports Server (NTRS)

    Zhang, S. N.; Zhang, Xiao-Ling; Yao, Yangsen

    2002-01-01

    System inclination angles have been determined for about 15 X-ray binaries, in which stellar mass black holes are considered to exist. These inclination angles range between 25 degrees and 80 degrees, but peaked between 60-70 degrees. This peak is not explained in the frame work of Newtonian gravity. However, this peak is reproduced naturally if we model the observed X-ray radiations as being produced in the accretion disks very close to the black hole horizons, where the extremely strong general and special relativistic effects, caused by the extremely strong gravity near the black hole horizons, modify the local radiation significantly as the X-rays propagate to the remote observer. Therefore the peak of the inclination angle distribution provides evidence or strong gravity around stellar mass black holes.

  12. Observational evidence of planetary wave influences on ozone enhancements over upper troposphere North Africa

    NASA Astrophysics Data System (ADS)

    Mengistu Tsidu, Gizaw; Ture, Kassahun; Sivakumar, V.

    2013-07-01

    MOZAIC instrument measured enhanced ozone on two occasions in February, 1996 and 1997 at cruise altitude over North Africa. The cause and source of ozone enhancements over the region are investigated using additional reanalysis data from ERA-Interim. The ERA-Interim reprocessed GOME ozone indicated existence of enhancement as well. Both observational data revealed that the increase in ozone has wider latitudinal coverage extending from North Europe upto North Africa. The geopotential heights and zonal wind from ERA-Interim have indicated existence of planetary-scale flow that allowed meridional airmass exchanges between subtropics and higher latitudes. The presence of troughs-ridge pattern are attributable to large amplitude waves of zonal wavenumber 1-5 propagating eastward in the winter hemisphere westerly current as determined from Hayashi spectra as well as local fractional variance spectra determined from Multitaper Method-Singular Value Decomposition (MTM-SVD) spectral method. MTM-SVD is also used to understand the role of these waves on ozone enhancement and variability during the observation period in a mechanistic approach. A joint analysis of driving field, such as wind and potential vorticity (PV) for which only signals of the dominant zonal wavenumbers of prevailing planetary waves are retained, has revealed strong linkage between wave activity and ozone enhancement over the region at a temporal cycle of 5.8 days. One of these features is the displacement of the polar vortex southward during the enhancements, allowing strong airmass, energy and momentum exchanges. Evidence of cutoff laws that are formed within the deep trough, characteristics of Rossby wave breaking, is also seen in the ozone horizontal distribution at different pressure levels during the events. The reconstruction of signals with the cycle of 5.8 days has shown that the time and strength of enhancement depend on the circulation patterns dictated by planetary-scale flow relative to the

  13. Phase fluctuations in a strongly disordered s-wave NbN superconductor close to the metal-insulator transition.

    PubMed

    Mondal, Mintu; Kamlapure, Anand; Chand, Madhavi; Saraswat, Garima; Kumar, Sanjeev; Jesudasan, John; Benfatto, L; Tripathi, Vikram; Raychaudhuri, Pratap

    2011-01-28

    We explore the role of phase fluctuations in a three-dimensional s-wave superconductor, NbN, as we approach the critical disorder for destruction of the superconducting state. Close to critical disorder, we observe a finite gap in the electronic spectrum which persists at temperatures well above T(c). The superfluid density is strongly suppressed at low temperatures and evolves towards a linear-T variation at higher temperatures. These observations provide strong evidence that phase fluctuations play a central role in the formation of a pseudogap state in a disordered s-wave superconductor.

  14. Starting Strong: Evidence-­Based Early Literacy Practices

    ERIC Educational Resources Information Center

    Blamey, Katrin; Beauchat, Katherine

    2016-01-01

    Four evidence-based instructional approaches create an essential resource for any early literacy teacher or coach. Improve your teaching practices in all areas of early literacy. Use four proven instructional approaches--standards based, evidenced based, assessment based, and student based--to improve their teaching practice in all areas of early…

  15. Patent foramen ovale closure and medical treatments for secondary stroke prevention: a systematic review of observational and randomized evidence.

    PubMed

    Kitsios, Georgios D; Dahabreh, Issa J; Abu Dabrh, Abd Moain; Thaler, David E; Kent, David M

    2012-02-01

    Patients discovered to have a patent foramen ovale in the setting of a cryptogenic stroke may be treated with percutaneous closure, antiplatelet therapy, or anticoagulants. A recent randomized trial (CLOSURE I) did not detect any benefit of closure over medical treatment alone; the optimal medical therapy is also unknown. We synthesized the available evidence on secondary stroke prevention in patients with patent foramen ovale and cryptogenic stroke. A MEDLINE search was performed for finding longitudinal studies investigating medical treatment or closure, meta-analysis of incidence rates (IR), and IR ratios of recurrent cerebrovascular events. Fifty-two single-arm studies and 7 comparative nonrandomized studies and the CLOSURE I trial were reviewed. The summary IR of recurrent stroke was 0.36 events (95% confidence interval [CI], 0.24-0.56) per 100 person-years with closure versus 2.53 events (95% CI, 1.91-3.35) per 100 person-years with medical therapy. In comparative observational studies, closure was superior to medical therapy (IR ratio=0.19; 95% CI, 0.07-0.54). The IR for the closure arm of the CLOSURE I trial was higher than the summary estimate from observational studies; there was no significant benefit of closure over medical treatment (P=0.002 comparing efficacy estimates between observational studies and the trial). Observational and randomized data (9 studies) comparing medical therapies were consistent and suggested that anticoagulants are superior to antiplatelets for preventing stroke recurrence (IR ratio=0.42; 95% CI, 0.18-0.98). Although further randomized trial data are needed to precisely determine the effects of closure on stroke recurrence, the results of CLOSURE I challenge the credibility of a substantial body of observational evidence strongly favoring mechanical closure over medical therapy.

  16. Direct observation of ring-opening dynamics in strong-field ionized selenophene using femtosecond inner-shell absorption spectroscopy

    DOE PAGES

    Lackner, Florian; Chatterley, Adam S.; Pemmaraju, C. D.; ...

    2016-12-21

    Femtosecond extreme ultraviolet transient absorption spectroscopy is used to explore strong-field ionization induced dynamics in selenophene (C 4H 4Se). The dynamics are monitored in real-time from the viewpoint of the Se atom by recording the temporal evolution of element-specific spectral features near the Se 3d inner-shell absorption edge (~58 eV). The interpretation of the experimental results is supported by first-principles time-dependent density functional theory calculations. The experiments simultaneously capture the instantaneous population of stable molecular ions, the emergence and decay of excited cation states, and the appearance of atomic fragments. The experiments reveal, in particular, insight into the strong-field inducedmore » ring-opening dynamics in the selenophene cation, which are traced by the emergence of non-cyclic molecules as well as the liberation of Se + ions within an overall time scale of approximately 170 fs. In this study, we propose that both products may be associated with dynamics on the same electronic surfaces but with different degrees of vibrational excitation. The time-dependent inner-shell absorption features provide direct evidence for a complex relaxation mechanism that may be approximated by a two-step model, whereby the initially prepared, excited cyclic cation decays within τ 1 = 80 ± 30 fs into a transient molecular species, which then gives rise to the emergence of bare Se + and ring-open cations within an additional τ 2 = 80 ± 30 fs. The combined experimental and theoretical results suggest a close relationship between σ* excited cation states and the observed ring-opening reactions. In conclusion, the findings demonstrate that the combination of femtosecond time-resolved core-level spectroscopy with ab initio estimates of spectroscopic signatures provide new insights into complex, ultrafast photochemical reactions such as ring-opening dynamics in organic molecules in real-time and with simultaneous

  17. Using Evidence-Centered Design to Create a Special Educator Observation System

    ERIC Educational Resources Information Center

    Johnson, Evelyn S.; Crawford, Angela R.; Moylan, Laura A.; Zheng, Yuzhu

    2018-01-01

    The Evidence-Centered Design (ECD) framework was used to create a special education teacher observation system, Recognizing Effective Special Education Teachers (RESET). Extensive reviews of research informed the domain analysis and modeling stages, and led to the conceptual framework in which effective special education teaching is…

  18. Observational Versus Experimental Studies: What’s the Evidence for a Hierarchy?

    PubMed Central

    Concato, John

    2004-01-01

    Summary: The tenets of evidence-based medicine include an emphasis on hierarchies of research design (i.e., study architecture). Often, a single randomized, controlled trial is considered to provide “truth,” whereas results from any observational study are viewed with suspicion. This paper describes information that contradicts and discourages such a rigid approach to evaluating the quality of research design. Unless a more balanced strategy evolves, new claims of methodological authority may be just as problematic as the traditional claims of medical authority that have been criticized by proponents of evidence-based medicine. PMID:15717036

  19. Current strategies for monitoring men with localised prostate cancer lack a strong evidence base: observational longitudinal study.

    PubMed

    Metcalfe, C; Tilling, K; Davis, M; Lane, J A; Martin, R M; Kynaston, H; Powell, P; Neal, D E; Hamdy, F; Donovan, J L

    2009-08-04

    The UK National Institute for Health and Clinical Excellence (NICE) guidance recommends conservative management of men with 'low-risk' localised prostate cancer, monitoring the disease using prostate-specific antigen (PSA) kinetics and re-biopsy. However, there is little evidence of the changes in PSA level that should alert to the need for clinical re-assessment. This study compares the alerts resulting from PSA kinetics and a novel longitudinal reference range approach, which incorporates age-related changes, during the monitoring of 408 men with localised prostate cancer. Men were monitored by regular PSA tests over a mean of 2.9 years, recording when a man's PSA doubling time fell below 2 years, PSA velocity exceeded 2 ng ml(-1) per year, or when his upper 10% reference range was exceeded. Prostate-specific antigen doubling time and PSA velocity alerted a high proportion of men initially but became unresponsive to changes with successive tests. Calculating doubling time using recent PSA measurements reduced the decline in response. The reference range method maintained responsiveness to changes in PSA level throughout the monitoring. The increasing unresponsiveness of PSA kinetics is a consequence of the underlying regression model. Novel methods are needed for evaluation in cohorts currently being managed by monitoring. Meanwhile, the NICE guidance should be cautious.

  20. The ASCA PV phase observation of FO Aquarii

    NASA Technical Reports Server (NTRS)

    Mukai, Koji; Ishida, Manabu; Osborne, Julian P.

    1994-01-01

    We report on a approximately 1-day Advanced Satellite for Cosmology and Astrophysics (ASCA) observation of the intermediate polar FO Aquarii. We find two distinctive spectral components, one unabsorbed and the other strongly absorbed; the observed 2-10 keV flux severely underestimates the total system luminosity, due to this strong absorption intrinsic to the binary. The absorbed component is dominant in terms of luminosity, and its light curve is simple. The unabsorbed component accounts for approximately 2% of the luminosity, and shows a much more complicated light curve. As the dominant component predominantly shows a sinusoidal modulation at the white dwarf spin period, it provides a strong evidence for a partial accretion disk in the system.

  1. Direct observation limits on antimatter gravitation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fischler, Mark; Lykken, Joe; Roberts, Tom

    2008-06-01

    The proposed Antihydrogen Gravity experiment at Fermilab (P981) will directly measure the gravitational attraction g between antihydrogen and the Earth, with an accuracy of 1% or better. The following key question has been asked by the PAC: Is a possible 1% difference between g and g already ruled out by other evidence? This memo presents the key points of existing evidence, to answer whether such a difference is ruled out (a) on the basis of direct observational evidence; and/or (b) on the basis of indirect evidence, combined with reasoning based on strongly held theoretical assumptions. The bottom line is thatmore » there are no direct observations or measurements of gravitational asymmetry which address the antimatter sector. There is evidence which by indirect reasoning can be taken to rule out such a difference, but the analysis needed to draw that conclusion rests on models and assumptions which are in question for other reasons and are thus worth testing. There is no compelling evidence or theoretical reason to rule out such a difference at the 1% level.« less

  2. Observations of strong ion-ion correlations in dense plasmas

    DOE PAGES

    Ma, T.; Fletcher, L.; Pak, A.; ...

    2014-04-24

    Using simultaneous spectrally, angularly, and temporally resolved x-ray scattering, we measure the pronounced ion-ion correlation peak in a strongly coupled plasma. Laser-driven shock-compressed aluminum at ~3× solid density is probed with high-energy photons at 17.9 keV created by molybdenum He-α emission in a laser-driven plasma source. The measured elastic scattering feature shows a well-pronounced correlation peak at a wave vector of k=4Å –1. The magnitude of this correlation peak cannot be described by standard plasma theories employing a linear screened Coulomb potential. Advanced models, including a strong short-range repulsion due to the inner structure of the aluminum ions are howevermore » in good agreement with the scattering data. These studies have demonstrated a new highly accurate diagnostic technique to directly measure the state of compression and the ion-ion correlations. Furthermore, we have since applied this new method in single-shot wave-number resolved S(k) measurements to characterize the physical properties of dense plasmas.« less

  3. MAVEN Observations of Magnetic Flux Ropes with a Strong Field Amplitude in the Martian Magnetosheath During the ICME Passage on 8 March 2015

    NASA Technical Reports Server (NTRS)

    Hara, Takuya; Luhmann, Janet G.; Halekas, Jasper S.; Espley, Jared R.; Seki, Kanako; Brain, David A.; Hasegawa, Hiroshi; McFadden, James P.; Mitchell, David L.; Mazelle, Christian; hide

    2016-01-01

    We present initial results of strong field amplitude flux ropes observed by Mars Atmosphere and Volatile EvolutioN (MAVEN) mission around Mars during the interplanetary coronal mass ejection (ICME) passage on 8 March 2015. The observed durations were shorter than 5 s and the magnetic field magnitudes peaked above 80 nT, which is a few times stronger than those usually seen in the magnetosheath barrier. These are the first unique observations that MAVEN detected such flux ropes with a strong field at high altitudes (greater than 5000 km). Across these structures, MAVEN coincidentally measured planetary heavy ions with energies higher than a few keV. The spatial properties inferred from the Grad-Shafranov equation suggest that the speed of the structure can be estimated at least an order of magnitude faster than those previously reported quiet-time counterparts. Hence, the space weather event like the ICME passage can be responsible for generating the observed strong field, fast-traveling flux ropes.

  4. Strong reproductive isolation between humans and Neanderthals inferred from observed patterns of introgression

    PubMed Central

    Currat, Mathias; Excoffier, Laurent

    2011-01-01

    Recent studies have revealed that 2–3% of the genome of non-Africans might come from Neanderthals, suggesting a more complex scenario of modern human evolution than previously anticipated. In this paper, we use a model of admixture during a spatial expansion to study the hybridization of Neanderthals with modern humans during their spread out of Africa. We find that observed low levels of Neanderthal ancestry in Eurasians are compatible with a very low rate of interbreeding (<2%), potentially attributable to a very strong avoidance of interspecific matings, a low fitness of hybrids, or both. These results suggesting the presence of very effective barriers to gene flow between the two species are robust to uncertainties about the exact demography of the Paleolithic populations, and they are also found to be compatible with the observed lack of mtDNA introgression. Our model additionally suggests that similarly low levels of introgression in Europe and Asia may result from distinct admixture events having occurred beyond the Middle East, after the split of Europeans and Asians. This hypothesis could be tested because it predicts that different components of Neanderthal ancestry should be present in Europeans and in Asians. PMID:21911389

  5. Strong reproductive isolation between humans and Neanderthals inferred from observed patterns of introgression.

    PubMed

    Currat, Mathias; Excoffier, Laurent

    2011-09-13

    Recent studies have revealed that 2-3% of the genome of non-Africans might come from Neanderthals, suggesting a more complex scenario of modern human evolution than previously anticipated. In this paper, we use a model of admixture during a spatial expansion to study the hybridization of Neanderthals with modern humans during their spread out of Africa. We find that observed low levels of Neanderthal ancestry in Eurasians are compatible with a very low rate of interbreeding (<2%), potentially attributable to a very strong avoidance of interspecific matings, a low fitness of hybrids, or both. These results suggesting the presence of very effective barriers to gene flow between the two species are robust to uncertainties about the exact demography of the Paleolithic populations, and they are also found to be compatible with the observed lack of mtDNA introgression. Our model additionally suggests that similarly low levels of introgression in Europe and Asia may result from distinct admixture events having occurred beyond the Middle East, after the split of Europeans and Asians. This hypothesis could be tested because it predicts that different components of Neanderthal ancestry should be present in Europeans and in Asians.

  6. Rainfall intensity and groundwater recharge: evidence from ground-based observations in East Africa (Invited)

    NASA Astrophysics Data System (ADS)

    Taylor, R. G.; Owor, M.; Kaponda, A.

    2013-12-01

    Global greenhouse-gas emissions serve to warm Africa more rapidly than the rest of the world. The intensification of precipitation that is associated with this warming, strongly influences terrestrial water budgets. This shift toward fewer but heavier rainfall events is expected to lead to more frequent and intense floods as well as more variable and lower soil moisture. However, its impact on groundwater recharge is unclear and in dispute. We review evidence from long (1 to 5 decades) time series of groundwater levels recorded in deeply weathered crystalline rock aquifers systems underlying land surfaces of low relief in Uganda and Tanzania. Borehole hydrographs consistently demonstrate a non-linear relationship between rainfall and recharge wherein heavy rainfalls exceeding a threshold contribute disproportionately to the recharge flux. Rapid responses observed in groundwater levels to rainfall events attest further to the importance of preferential pathways in enabling rain-fed recharge via soil macro-pores. Our results suggest that, in these environments, increased use of groundwater to offset periods of low surface flow and to supplement soil moisture through irrigation may prove a logical strategy to enhance regional water and food security.

  7. Predictions for boson-jet observables and fragmentation function ratios from a hybrid strong/weak coupling model for jet quenching

    DOE PAGES

    Casalderrey-Solana, Jorge; Gulhan, Doga Can; Milhano, José Guilherme; ...

    2016-03-09

    We have previously introduced a hybrid strong/weak coupling model for jet quenching in heavy ion collisions in which we describe the production and fragmentation of jets at weak coupling, using Pythia, and describe the rate at which each parton in the jet shower loses energy as it propagates through the strongly coupled plasma, dE/dx, using an expression computed holographically at strong coupling. The model has a single free parameter that we fit to a single experimental measurement. We then confront our model with experimental data on many other jet observables, focusing in this paper on boson-jet observables, finding that itmore » provides a good description of present jet data. Next, we provide the predictions of our hybrid model for many measurements to come, including those for inclusive jet, dijet, photon-jet and Z-jet observables in heavy ion collisions with energy √s = 5 : 02 ATeV coming soon at the LHC. As the statistical uncertainties on near-future measurements of photon-jet observables are expected to be much smaller than those in present data, with about an order of magnitude more photon-jet events expected, predictions for these observables are particularly important. We find that most of our pre- and post-dictions do not depend sensitively on the form we choose for the rate of energy loss dE/dx of the partons in the shower. This gives our predictions considerable robustness. To better discriminate between possible forms for the rate of energy loss, though, we must turn to intrajet observables. Here, we focus on ratios of fragmentation functions. Finally, we close with a suggestion for a particular ratio, between the fragmentation functions of inclusive and associated jets with the same kinematics in the same collisions, which is particularly sensitive to the x- and E-dependence of dE/dx, and hence may be used to learn which mechanism of parton energy loss best describes the quenching of jets.« less

  8. Observational Evidence of the "Tightening of Hadley Ascent"

    NASA Astrophysics Data System (ADS)

    Su, H.; Wu, L.; Jiang, J. H.

    2017-12-01

    Recent studies show that the Hadley Circulation undergoes complicated structure changes under global warming (e.g., Su et al., 2014; Lau and Kim 2015; Byrne and Schneider 2016; Su et al., 2017)). Accompanied by the widening of the descent zone, a narrowing of the ascending branch of the Hadley Circulation is simulated in most climate models. The magnitude of the tightening of Hadley ascent (THA) in the models is found to be highly correlated with the decrease of tropical high cloud fraction, which is a major contributor to the inter-model spread of the longwave radiative cooling rate and the global-mean precipitation change per degree of surface warming (Su et al. 2017). While the THA is a common feature in the models, its observational evidence is limited. We have examined a number of reanalyses and satellite datasets to identify the indicators of the THA in terms of large-scale winds, water vapor, cloud and precipitation changes in the past decades. The robustness of the THA in the observations and the differences between various datasets will be presented.

  9. Inca Moon: Some Evidence of Lunar Observations in Tahuantinsuyu

    NASA Astrophysics Data System (ADS)

    Ziółkowski, Mariusz; Kościuk, Jacek; Astete, Fernando

    So far, scientists have not investigated thoroughly if and for what purpose the Incas observed the Moon. As far as the orientation of architectural structures is concerned, the researchers focus their attention almost entirely on the position of the Sun. However, a more accurate analysis of two well-known sites - the caves of Intimachay and Cusilluchayoc - may provide evidence of their function as observatories of the lunar 18.6-year cycle. Those results may confirm the hypothesis, presented some years ago, that the Incas had elaborated a rudimentary method of predicting lunar eclipses.

  10. Observational Evidence For The Comet-Like Heliosphere

    NASA Astrophysics Data System (ADS)

    Bzowski, M.; Czechowski, A.; Funsten, H. O.; Grygorczuk, J.; Heerikhuisen, J.; Kubiak, M. A.; Moebius, E.; McComas, D. J.; Schwadron, N.; Sokol, J. M.; Swaczyna, P.; Zirnstein, E.

    2017-12-01

    The shape of the heliosphere is a subject of ongoing debate. The traditional comet-like image has recently been challenged by ideas of croissant- or bubble-like forms. Here we seek to resolve this debate by confronting available observational evidence with global modeling. Several MHD models of a comet-like heliosphere were used to simulate the radius and center of the IBEX Ribbon to fit the direction and intensity of the interstellar magnetic field (ISMF). These models assumed the secondary ENA emission mechanism, which was recently strengthened due to direct measurement of the distance to the Ribbon source most likely just beyond the heliopause. The same mechanism explains the dependence of the Ribbon center position on energy due to the latitudinal structure of solar wind. The obtained ISMF vector agrees among these models and is consistent with the draped IMF measured by Voyager. Independently, we have shown by modeling that the Warm Breeze discovered by IBEX is naturally created in the outer heliosheath due to charge-exchange between interstellar He+ ions and He atoms. Now we simulate the Warm Breeze for various directions and intensities of the local IMF and we find that the simulation results are in best agreement with IBEX observations for the IMF vector obtained from the above-mentioned Ribbon analyses and Voyager measurements. These arguments, along with the co-planarity of the inflow directions of interstellar neutral H, He, O, and the Warm Breeze, directions of the Ribbon center and ISMF, as well as measurements of the plasma flow directions in the IHS by Voyager 2 indicate the existence of a common plane of approximate mirror symmetry of the heliosphere, defined by the directions of ISMF and the Sun's motion through the local interstellar medium. This suggests that the global structure of the outer heliosphere mostly results from the conditions in the local interstellar medium and the Sun's velocity. This evidence, obtained from very different

  11. Strong refraction near the Venus surface - Effects observed by descent probes

    NASA Technical Reports Server (NTRS)

    Croft, T. A.

    1982-01-01

    The telemetry signals from Pioneer Venus probes indicated the strong downward refraction of radio waves. As the probes descended, the strength of the direct signal decreased because of absorption and refractive defocusing. During the last 30 km of descent there was a second measured component in addition to the direct signal. Strong atmospheric reaction is important in strengthening echoes that are scattered toward the earth. Such surface-reflected signals are good indicators of horizontal winds.

  12. Line-of-sight structure toward strong lensing galaxy clusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bayliss, Matthew B.; Johnson, Traci; Sharon, Keren

    2014-03-01

    We present an analysis of the line-of-sight structure toward a sample of 10 strong lensing cluster cores. Structure is traced by groups that are identified spectroscopically in the redshift range, 0.1 ≤ z ≤ 0.9, and we measure the projected angular and comoving separations between each group and the primary strong lensing clusters in each corresponding line of sight. From these data we measure the distribution of projected angular separations between the primary strong lensing clusters and uncorrelated large-scale structure as traced by groups. We then compare the observed distribution of angular separations for our strong lensing selected lines ofmore » sight against the distribution of groups that is predicted for clusters lying along random lines of sight. There is clear evidence for an excess of structure along the line of sight at small angular separations (θ ≤ 6') along the strong lensing selected lines of sight, indicating that uncorrelated structure is a significant systematic that contributes to producing galaxy clusters with large cross sections for strong lensing. The prevalence of line-of-sight structure is one of several biases in strong lensing clusters that can potentially be folded into cosmological measurements using galaxy cluster samples. These results also have implications for current and future studies—such as the Hubble Space Telescope Frontier Fields—that make use of massive galaxy cluster lenses as precision cosmological telescopes; it is essential that the contribution of line-of-sight structure be carefully accounted for in the strong lens modeling of the cluster lenses.« less

  13. Evidence for Precise Calendrical Observations in the 17th Century at the `Bruchhauser Steine', Olsberg, Northrhine-Westphalia, Germany

    NASA Astrophysics Data System (ADS)

    Steinrücken, B.

    The `Bruchhauser Steine', four large rocks of volcanic origin in southern Westphalia, form perfect foresights for calendrical observations from the surrounding country. The ancient walls and embankments on the `Istenberg' with the rocks as cornerstones were built 500 BC. In the landscape are placed shrines with images of Christian saints, erected in the late 17th and the early 18th century. The positions of these shrines can be interpreted as observing sites with respect to the stones. The foresights reach several degrees to the sky, so variations in the astronomical refraction are strongly suppressed. The most impressive observing site with a shrine of 1699 (8o31'13'' E, 51o18'49'' N) is exactly at the position to observe the summer solstice sunrise at the topmost rock, the `Feldstein'. The solstice sun rises between two stones and grazes the Feldstein at 6:20 CEST. Today the sun is obstructed 2'-3' by the stone. Taking into account the slight variation of the obliquity of the ecliptic of 2' since 1699 the grazing procedure at the time of erection was perfect, without any obstruction of the suns disc. Similar shrines are placed at positions to observe the sunrise on May 1st in the identical manner (8o29'39'' E, 51o18'41'' N) and the lunar declination minimum on the meridian (8o32'44'' E, 51o20'33'' N). Some evidence indicates a prehistoric origin of this calendrical system.

  14. Observation of strong oscillations of areal mass in an unsupported shock wave produced by a short laser pulse

    NASA Astrophysics Data System (ADS)

    Aglitskiy, Y.; Karasik, M.; Velikovich, A. L.; Serlin, V.; Weaver, J. L.; Kessler, T. J.; Schmitt, A. J.; Obenschain, S. P.; Metzler, N.; Oh, J.

    2011-10-01

    The first experimental study of hydrodynamic perturbation evolution in a strong unsupported shock wave, which is immediately followed by a rarefaction wave, is reported. Our planar solid polystyrene laser-machined targets, 50 to 100 μm thick, rippled from the front side with a single-mode wavelength 30 or 45 μm and peak-to-valley amplitude 4 to 6 μm, were irradiated with a 350 ps long Nike KrF laser pulse at peak intensity of up to 330 TW/cm2. The perturbation evolution in the target was observed using face-on monochromatic x-ray radiography while the pulse lasted and for 3 to 4 ns after it ended. While the driving pulse was on, the areal mass modulation amplitude in the target was observed to grow by a factor of up to ~4 due to the ablative Richtmyer-Meshkov instability. After the end of the pulse, while the strong unsupported shock wave propagated through the unperturbed target, the theoretically predicted large oscillations of the areal mass [A. L. Velikovich et al., Phys. Plasmas 10, 3270 (2003)] were observed. Multiple phase reversals of the areal mass modulation have been detected. Work supported by DOE/NNSA and Office of Naval Research.

  15. Additional Evidence for the Accuracy of Biographical Data: Long-Term Retest and Observer Ratings.

    ERIC Educational Resources Information Center

    Shaffer, Garnett Stokes; And Others

    1986-01-01

    Investigated accuracy of responses to biodata questionnaire using a test-retest design and informed external observers for verification. Responses from 237 subjects and 200 observers provided evidence that many responses to biodata questionnaire were accurate. Assessed sources of inaccuracy, including social desirability effects, and noted…

  16. Strong evidence for the presence of the tick Hyalomma marginatum Koch, 1844 in southern continental France.

    PubMed

    Vial, Laurence; Stachurski, Frédéric; Leblond, Agnès; Huber, Karine; Vourc'h, Gwenaël; René-Martellet, Magalie; Desjardins, Isabelle; Balança, Gilles; Grosbois, Vladimir; Pradier, Sophie; Gély, Marie; Appelgren, Anaïs; Estrada-Peña, Agustin

    2016-10-01

    Hyalomma ticks can transmit several human and animal pathogens in Eurasia and Africa. Interest in Hyalomma marginatum has increased since the recent (re)emergence of Crimean-Congo Hemorrhagic fever in the Palearctic region. Until now, continental France has been considered free of this tick species. Nevertheless, the existence of incomplete and occasionally incorrect records has maintained confusion about its status. Based on several tick sampling campaigns conducted on horses and birds from 2007 to 2016, we provided very strong evidence for the presence of reproducing populations of H. marginatum in parts of southern continental France. We also confirmed the introduction of immature developmental stages of H. marginatum, as well as H. rufipes, into France probably through trans-Mediterranean bird migrations. Copyright © 2016. Published by Elsevier GmbH.

  17. Observational evidence for Alfven waves in the solar atmosphere (Invited)

    NASA Astrophysics Data System (ADS)

    De Pontieu, B.

    2013-12-01

    Alfven waves have long been suspected of playing an important role in both heating the corona and accelerating the solar wind. Recently, more and more observational evidence for the presence of such waves has been reported in both the corona and the lower solar atmosphere. I will review observations of the properties and presence of Alfven waves from CoMP, Hinode, AIA and ground-based telescopes in both coronal lines and the lower solar atmosphere. I will discuss our current understanding of the importance of these waves for the energy balance of the corona. I will also present initial results of the Interface Region Imaging Spectrograph (IRIS) which was launched in June 2013 and obtains images and spectra in both the far and near ultraviolet.

  18. Observation of strong reflection of electron waves exiting a ballistic channel at low energy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vaz, Canute I.; Campbell, Jason P.; Ryan, Jason T.

    2016-06-15

    Wave scattering by a potential step is a ubiquitous concept. Thus, it is surprising that theoretical treatments of ballistic transport in nanoscale devices, from quantum point contacts to ballistic transistors, assume no reflection even when the potential step is encountered upon exiting the device. Experiments so far seem to support this even if it is not clear why. Here we report clear evidence of coherent reflection when electron wave exits the channel of a nanoscale transistor and when the electron energy is low. The observed behavior is well described by a simple rectangular potential barrier model which the Schrodinger’s equationmore » can be solved exactly. We can explain why reflection is not observed in most situations but cannot be ignored in some important situations. Our experiment also represents a direct measurement of electron injection velocity - a critical quantity in nanoscale transistors that is widely considered not measurable.« less

  19. Evidence for strong, widespread chlorine radical chemistry associated with pollution outflow from continental Asia

    PubMed Central

    Baker, Angela K.; Sauvage, Carina; Thorenz, Ute R.; van Velthoven, Peter; Oram, David E.; Zahn, Andreas; Brenninkmeijer, Carl A. M.; Williams, Jonathan

    2016-01-01

    The chlorine radical is a potent atmospheric oxidant, capable of perturbing tropospheric oxidative cycles normally controlled by the hydroxyl radical. Significantly faster reaction rates allow chlorine radicals to expedite oxidation of hydrocarbons, including methane, and in polluted environments, to enhance ozone production. Here we present evidence, from the CARIBIC airborne dataset, for extensive chlorine radical chemistry associated with Asian pollution outflow, from airborne observations made over the Malaysian Peninsula in winter. This region is known for persistent convection that regularly delivers surface air to higher altitudes and serves as a major transport pathway into the stratosphere. Oxidant ratios inferred from hydrocarbon relationships show that chlorine radicals were regionally more important than hydroxyl radicals for alkane oxidation and were also important for methane and alkene oxidation (>10%). Our observations reveal pollution-related chlorine chemistry that is both widespread and recurrent, and has implications for tropospheric oxidizing capacity, stratospheric composition and ozone chemistry. PMID:27845366

  20. Evidence for cannabis and cannabinoids for epilepsy: a systematic review of controlled and observational evidence.

    PubMed

    Stockings, Emily; Zagic, Dino; Campbell, Gabrielle; Weier, Megan; Hall, Wayne D; Nielsen, Suzanne; Herkes, Geoffrey K; Farrell, Michael; Degenhardt, Louisa

    2018-07-01

    Review evidence for cannabinoids as adjunctive treatments for treatment-resistant epilepsy. Systematic search of Medline, Embase and PsycINFO was conducted in October 2017. Outcomes were: 50%+ seizure reduction, complete seizure freedom; improved quality of life (QoL). Tolerability/safety were assessed by study withdrawals, adverse events (AEs) and serious adverse events (SAEs). Analyses were conducted in Stata V.15.0. 36 studies were identified: 6 randomised controlled trials (RCTs), 30 observational studies. Mean age of participants was 16.1 years (range 0.5-55 years). Cannabidiol (CBD) 20 mg/kg/day was more effective than placebo at reducing seizure frequency by 50%+(relative risk (RR) 1.74, 95% CI 1.24 to 2.43, 2 RCTs, 291 patients, low Grades of Recommendation, Assessment, Development and Evaluation (GRADE) rating). The number needed to treat for one person using CBD to experience 50%+ seizure reduction was 8 (95% CI 6 to 17). CBD was more effective than placebo at achieving complete seizure freedom (RR 6.17, 95% CI 1.50 to 25.32, 3 RCTs, 306 patients, low GRADE rating), and improving QoL (RR 1.73, 95% CI 1.33 to 2.26), however increased risk of AEs (RR 1.24, 95% CI 1.13 to 1.36) and SAEs (RR 2.55, 95% CI 1.48 to 4.38). Pooled across 17 observational studies, 48.5% (95% CI 39.0% to 58.1%) of patients reported 50%+ reductions in seizures; in 14 observational studies 8.5% (95% CI 3.8% to 14.5%) were seizure-free. Twelve observational studies reported improved QoL (55.8%, 95% CI 40.5 to 70.6); 50.6% (95% CI 31.7 to 69.4) AEs and 2.2% (95% CI 0 to 7.9) SAEs. Pharmaceutical-grade CBD as adjuvant treatment in paediatric-onset drug-resistant epilepsy may reduce seizure frequency. Existing RCT evidence is mostly in paediatric samples with rare and severe epilepsy syndromes; RCTs examining other syndromes and cannabinoids are needed. CRD42017055412. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article

  1. Evidence of Plumes on Europa from far-ultraviolet observations with HST

    NASA Astrophysics Data System (ADS)

    Sparks, William B.; McGrath, Melissa; Schmidt, Britney; Bergeron, Eddie; Hand, Kevin; Spencer, John; Cracraft, Misty; Deustua, Susana

    2018-01-01

    Evidence for plumes of water emerging from the icy surface of Europa has been found by the Hubble Space Telescope (HST) using two different UV observing techniques. Roth et al. (2014) found line emission from the dissociation products of water. Sparks et al. (2016, 2017) found evidence for off-limb continuum absorption as Europa transited Jupiter. We describe the transit method which obtains far ultraviolet images of Europa as it passes in front of the smooth face of Jupiter, seeking off-limb absorption patches that may be due to plumes on Europa. This approach exploits the time resolution, sensitivity and spatial resolution of HST, coupled to the high cross-sections for molecules of interest at these wavelengths. We show that a well-localized plume candidate appears more than once, and that it is at the same position as a nighttime thermal anomaly seen by the Galileo spacecraft, the warmest point on the observed Europa nightside. The favored interpretation of the thermal anomaly is a modification to the local thermal inertia, which could be causally related to plume activity. Future plans for additional work in this area are described.

  2. Subcycle dynamics of Coulomb asymmetry in strong elliptical laser fields.

    PubMed

    Li, Min; Liu, Yunquan; Liu, Hong; Ning, Qicheng; Fu, Libin; Liu, Jie; Deng, Yongkai; Wu, Chengyin; Peng, Liang-You; Peng, Liangyou; Gong, Qihuang

    2013-07-12

    We measure photoelectron angular distributions of noble gases in intense elliptically polarized laser fields, which indicate strong structure-dependent Coulomb asymmetry. Using a dedicated semiclassical model, we have disentangled the contribution of direct ionization and multiple forward scattering on Coulomb asymmetry in elliptical laser fields. Our theory quantifies the roles of the ionic potential and initial transverse momentum on Coulomb asymmetry, proving that the small lobes of asymmetry are induced by direct ionization and the strong asymmetry is induced by multiple forward scattering in the ionic potential. Both processes are distorted by the Coulomb force acting on the electrons after tunneling. Lowering the ionization potential, the relative contribution of direct ionization on Coulomb asymmetry substantially decreases and Coulomb focusing on multiple rescattering is more important. We do not observe evident initial longitudinal momentum spread at the tunnel exit according to our simulation.

  3. Simultaneous Extreme-Ultraviolet Explorer and Optical Observations of Ad Leonis: Evidence for Large Coronal Loops and the Neupert Effect in Stellar Flares

    NASA Technical Reports Server (NTRS)

    Hawley, Suzanne L.; Fisher, George H.; Simon, Theodore; Cully, Scott L.; Deustua, Susana E.; Jablonski, Marek; Johns-Krull, Christopher; Pettersen, Bjorn R.; Smith, Verne; Spiesman, William J.; hide

    1995-01-01

    We report on the first simultaneous Extreme-Ultraviolet Explorer (EUVE) and optical observations of flares on the dMe flare star AD Leonis. The data show the following features: (1) Two flares (one large and one of moderate size) of several hours duration were observed in the EUV wavelength range; (2) Flare emission observed in the optical precedes the emission seen with EUVE; and (3) Several diminutions (DIMs) in the optical continuum were observed during the period of optical flare activity. To interpret these data, we develop a technique for deriving the coronal loop length from the observed rise and decay behavior of the EUV flare. The technique is generally applicable to existing and future coronal observations of stellar flares. We also determine the pressure, column depth, emission measure, loop cross-sectional area, and peak thermal energy during the two EUV flares, and the temperature, area coverage, and energy of the optical continuum emission. When the optical and coronal data are combined, we find convincing evidence of a stellar 'Neupert effect' which is a strong signature of chromospheric evaporation models. We then argue that the known spatial correlation of white-light emission with hard X-ray emission in solar flares, and the identification of the hard X-ray emission with nonthermal bremsstrahlung produced by accelerated electrons, provides evidence that flare heating on dMe stars is produced by the same electron precipitation mechanism that is inferred to occur on the Sun. We provide a thorough picture of the physical processes that are operative during the largest EUV flare, compare and contrast this picture with the canonical solar flare model, and conclude that the coronal loop length may be the most important factor in determining the flare rise time and energetics.

  4. Chandra and ALMA observations of the nuclear activity in two strongly lensed star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Massardi, M.; Enia, A. F. M.; Negrello, M.; Mancuso, C.; Lapi, A.; Vignali, C.; Gilli, R.; Burkutean, S.; Danese, L.; Zotti, G. De

    2018-02-01

    Aim. According to coevolutionary scenarios, nuclear activity and star formation play relevant roles in the early stages of galaxy formation. We aim at identifying them in high-redshift galaxies by exploiting high-resolution and high-sensitivity X-ray and millimeter-wavelength data to confirm the presence or absence of star formation and nuclear activity and describe their relative roles in shaping the spectral energy distributions and in contributing to the energy budgets of the galaxies. Methods: We present the data, model, and analysis in the X-ray and millimeter (mm) bands for two strongly lensed galaxies, SDP.9 (HATLAS J090740.0-004200) and SDP.11 (HATLAS J091043.1-000322), which we selected in the Herschel-ATLAS catalogs for their excess emission in the mid-IR regime at redshift ≳1.5. This emission suggests nuclear activity in the early stages of galaxy formation. We observed both of them with Chandra ACIS-S in the X-ray regime and analyzed the high-resolution mm data that are available in the ALMA Science Archive for SDP.9. By combining the information available in mm, optical, and X-ray bands, we reconstructed the source morphology. Results: Both targets were detected in the X-ray, which strongly indicates highly obscured nuclear activity. ALMA observations for SDP.9 for the continuum and CO(6-5) spectral line with high resolution (0.02 arcsec corresponding to 65 pc at the distance of the galaxy) allowed us to estimate the lensed galaxy redshift to a better accuracy than pre-ALMA estimates (1.5753 ± 0.0003) and to model the emission of the optical, millimetric, and X-ray band for this galaxy. We demonstrate that the X-ray emission is generated in the nuclear environment, which strongly supports that this object has nuclear activity. On the basis of the X-ray data, we attempt an estimate of the black hole properties in these galaxies. Conclusions: By taking advantage of the lensing magnification, we identify weak nuclear activity associated with high

  5. Strong Cosmic Censorship

    NASA Astrophysics Data System (ADS)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  6. On observation of local strong heterogeneity in the Earth's inner core below southeastern Asia

    NASA Astrophysics Data System (ADS)

    Krasnoshchekov, D. N.; Kaazik, P. B.; Ovtchinnikov, V. M.

    2016-12-01

    The dimensions and nature of multi-scale structural heterogeneities in the Earth's inner core (IC) provide important constraints on its mineralogy and formation history. Teleseismic body waves with turn points close to the inner core boundary (ICB) provide a unique tool for imaging the fine structure of the upper IC. In this study, we invoke differential travel times and amplitudes of PKPBC and PKPDF waveforms observed in crossing polar and equatorial paths to provide more constraints on the heterogeneity previously located in the quasi-eastern hemisphere of the IC (Kaazik et al., 2015; Krasnoshchekov et al., 2016). A more refined analysis of quasi-polar PKPBC/PKPDF amplitude ratios measured within the heterogeneity indicates that seismic attenuation is both frequency and depth dependent, and its relatively low Q-factor at 1 Hz of approximately 118 tends to grow with depth. Outside the heterogeneity, no pronounced polar-equatorial differences are observed; the estimated Q factor is about twice as large and not directionally dependent. We also analyse new differential travel times of rays that enable sampling of the anomaly at greater depths. The analysis exhibits the polar - equatorial contrasts observed in the heterogeneity terminate at approximately 520 km below the ICB, which we interpret to be its bottom. The earlier interpretation of the heterogeneity in terms of strong anisotropic volume amidst the almost isotropic eastern hemisphere of the IC can be retained, and the lower bound of anisotropy strength within the anomaly is determined to be 2%.

  7. TRMM-TMI Satellite Observed Soil Moisture and Vegetation Density (1998-2005) Show Strong Connection with El Nino in Eastern Australia

    NASA Technical Reports Server (NTRS)

    Liu, Yi; van Dijk, Albert I.J.M.; Owe, Manfred

    2007-01-01

    Spatiotemporal patterns in soil moisture and vegetation water content across mainland Australia were investigated from 1998 through 2005, using TRMMITMI passive microwave observations. The Empirical Orthogonal Function technique was used to extract dominant spatial and temporal patterns in retrieved estimates of moisture content for the top 1-cm of soil (theta) and vegetation moisture content (via optical depth tau). The dominant temporal theta and tau patterns were strongly correlated to El Nino/Southern Oscillation (ENSO) in spring (3 = 0.90), and to a progressively lesser extent autumn, summer and winter. The Indian Ocean Dipole (IOD) index also explained part of the variation in spring 8 and z. Cluster analysis suggested that the regions most affected by ENS0 are mainly located in eastern Australia. The results suggest that the drought conditions experienced in eastern Australia since 2000 an clearly expressed in these satellite observations have a strong connection with ENSO patterns.

  8. Feature long axis size and local luminance contrast determine ship target acquisition performance: strong evidence for the TOD case

    NASA Astrophysics Data System (ADS)

    Bijl, Piet; Toet, Alexander; Kooi, Frank L.

    2016-10-01

    Visual images of a civilian target ship on a sea background were produced using a CAD model. The total set consisted of 264 images and included 3 different color schemes, 2 ship viewing aspects, 5 sun illumination conditions, 2 sea reflection values, 2 ship positions with respect to the horizon and 3 values of atmospheric contrast reduction. In a perception experiment, the images were presented on a display in a long darkened corridor. Observers were asked to indicate the range at which they were able to detect the ship and classify the following 5 ship elements: accommodation, funnel, hull, mast, and hat above the bridge. This resulted in a total of 1584 Target Acquisition (TA) range estimates for two observers. Next, the ship contour, ship elements and corresponding TA ranges were analyzed applying several feature size and contrast measures. Most data coincide on a contrast versus angular size plot using (1) the long axis as characteristic ship/ship feature size and (2) local Weber contrast as characteristic ship/ship feature contrast. Finally, the data were compared with a variety of visual performance functions assumed to be representative for Target Acquisition: the TOD (Triangle Orientation Discrimination), MRC (Minimum Resolvable Contrast), CTF (Contrast Threshold Function), TTP (Targeting Task Performance) metric and circular disc detection data for the unaided eye (Blackwell). The results provide strong evidence for the TOD case: both position and slope of the TOD curve match the ship detection and classification data without any free parameter. In contrast, the MRC and CTF are too steep, the TTP and disc detection curves are too shallow and all these curves need an overall scaling factor in order to coincide with the ship and ship feature recognition data.

  9. Mismeasurement and the resonance of strong confounders: uncorrelated errors.

    PubMed

    Marshall, J R; Hastrup, J L

    1996-05-15

    Greenland first documented (Am J Epidemiol 1980; 112:564-9) that error in the measurement of a confounder could resonate--that it could bias estimates of other study variables, and that the bias could persist even with statistical adjustment for the confounder as measured. An important question is raised by this finding: can such bias be more than trivial within the bounds of realistic data configurations? The authors examine several situations involving dichotomous and continuous data in which a confounder and a null variable are measured with error, and they assess the extent of resultant bias in estimates of the effect of the null variable. They show that, with continuous variables, measurement error amounting to 40% of observed variance in the confounder could cause the observed impact of the null study variable to appear to alter risk by as much as 30%. Similarly, they show, with dichotomous independent variables, that 15% measurement error in the form of misclassification could lead the null study variable to appear to alter risk by as much as 50%. Such bias would result only from strong confounding. Measurement error would obscure the evidence that strong confounding is a likely problem. These results support the need for every epidemiologic inquiry to include evaluations of measurement error in each variable considered.

  10. On the Nature of the Compact Object in SS 433: Observational Evidence of X-ray Photon Index Saturation

    NASA Astrophysics Data System (ADS)

    Seifina, Elena; Titarchuk, Lev

    2010-10-01

    We present an analysis of the X-ray spectral properties observed from the black hole candidate (BHC) binary SS 433. We have analyzed Rossi X-ray Timing Explorer data from this source, coordinated with Green Bank Interferometer/RATAN-600. We show that SS 433 undergoes an X-ray spectral transition from the low hard state to the intermediate state (IS). We show that the X-ray broadband energy spectra during all spectral states are well fitted by a sum of the so-called bulk motion Comptonization (BMC) component and by two (broad and narrow) Gaussians for the continuum and line emissions, respectively. In addition to these spectral model components, we also find a strong feature that we identify as a "blackbody-like (BB)" component in which the color temperature is in the range of 4-5 keV in 24 IS spectra during the radio outburst decay in SS 433. Our observational results on the "high-temperature BB" bump lead us to suggest the presence of gravitationally redshifted annihilation line emission in this source. In fact, this spectral feature has been recently reproduced in Monte Carlo simulations by Laurent & Titarchuk. We have also established the photon index saturation at about 2.3 in index versus mass accretion correlation. This index-mass accretion correlation allows us to evaluate the low limit of the black hole (BH) mass of the compact object in SS 433, M_{{bh}}≳ 2 solar masses, using the scaling method using BHC GX 339 - 4 as a reference source. Our estimate of the BH mass in SS 433 is consistent with the recent BH mass measurement using the radial velocity measurements of the binary system by Hillwig & Gies, who find that Mx = (4.3 ± 0.8) solar masses. This is the smallest BH mass found up to now among all BH sources. Moreover, the index saturation effect versus mass accretion rate revealed in SS 433, as in a number of other BH candidates, is strong observational evidence for the presence of a BH in SS 433.

  11. On the Nature of the Compact Object in SS 433. Observational Evidence of X-Ray Photon Index Saturation

    NASA Technical Reports Server (NTRS)

    Seifina, Elena; Titarchuk, Lev

    2010-01-01

    We present an analysis of the X-ray spectral properties observed from black hole , candidate (BHC) binary SS 433. We have analyzed Rossi X-ray Time Explorer (RXTE) data from this source, coordinated with Green Bank Interferometer/RATAN-600. We show that SS 433 undergoes a X-ray spectral transition from the low hard state (LHS) to the intermediate state (IS). We show that the X-ray broad-band energy spectra during all spectral states are well fit by a sum of so called "Bulk Motion Comptonization (BMC) component" and by two (broad and narrow) Gaussians for the continuum and line emissions respectively. In addition to these spectral model components we also find a strong feature that we identify as a" blackbody-like (BB)" component which color temperature is in the range of 4-5 keV in 24 IS spectra during the radio outburst decay in SS 433. Our observational results on the "high temperature BB" bump leads us to suggest the presence of gravitationally redshifted annihilation line emission in this source. In fact this spectral feature has been recently reproduced in Monte Carlo simulations by Laurent and Titarchuk. We have also established the photon index saturation at about 2.3 in index vs mass accretion correlation. This index-mass accretion correlation allows us to evaluate the low limit of black hole (BH) mass of compact object in SS 433, M(sub bh) approximately > 2 solar masses, using the scaling method using BHC GX 339-4 as a reference source. Our estimate of the BH mass in SS 433 is consistent with recent BH mass measurement using the radial-velocity measurements of the binary system by Hillwig & Gies who find that M(sub x)( = (4.3 +/- 0.8) solar masses. This is the smallest BH mass found up to now among all BH sources. Moreover, the index saturation effect versus mass accretion rate revealed in SS 433, like in a number of other BH candidates, is the strong observational evidence for the presence of a BH in SS 433.

  12. Evidence Accumulator or Decision Threshold – Which Cortical Mechanism are We Observing?

    PubMed Central

    Simen, Patrick

    2012-01-01

    Most psychological models of perceptual decision making are of the accumulation-to-threshold variety. The neural basis of accumulation in parietal and prefrontal cortex is therefore a topic of great interest in neuroscience. In contrast, threshold mechanisms have received less attention, and their neural basis has usually been sought in subcortical structures. Here I analyze a model of a decision threshold that can be implemented in the same cortical areas as evidence accumulators, and whose behavior bears on two open questions in decision neuroscience: (1) When ramping activity is observed in a brain region during decision making, does it reflect evidence accumulation? (2) Are changes in speed-accuracy tradeoffs and response biases more likely to be achieved by changes in thresholds, or in accumulation rates and starting points? The analysis suggests that task-modulated ramping activity, by itself, is weak evidence that a brain area mediates evidence accumulation as opposed to threshold readout; and that signs of modulated accumulation are as likely to indicate threshold adaptation as adaptation of starting points and accumulation rates. These conclusions imply that how thresholds are modeled can dramatically impact accumulator-based interpretations of this data. PMID:22737136

  13. LENSED: a code for the forward reconstruction of lenses and sources from strong lensing observations

    NASA Astrophysics Data System (ADS)

    Tessore, Nicolas; Bellagamba, Fabio; Metcalf, R. Benton

    2016-12-01

    Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present LENSED, a new code which performs forward parametric modelling of strong lenses. LENSED takes advantage of a massively parallel ray-tracing kernel to perform the necessary calculations on a modern graphics processing unit (GPU). This makes the precise rendering of the background lensed sources much faster, and allows the simultaneous optimization of tens of parameters for the selected model. With a single run, the code is able to obtain the full posterior probability distribution for the lens light, the mass distribution and the background source at the same time. LENSED is first tested on mock images which reproduce realistic space-based observations of lensing systems. In this way, we show that it is able to recover unbiased estimates of the lens parameters, even when the sources do not follow exactly the assumed model. Then, we apply it to a subsample of the Sloan Lens ACS Survey lenses, in order to demonstrate its use on real data. The results generally agree with the literature, and highlight the flexibility and robustness of the algorithm.

  14. The relationship between defecation and feeding in nestling birds: observational and experimental evidence.

    PubMed

    Quan, Rui-Chang; Li, Huan; Wang, Bo; Goodale, Eben

    2015-01-01

    Adult birds clean the nest by consuming or transporting feces, which is thought to be important in order to lower the levels of parasites, pathogens and predation at the nest. If nestlings were to defecate when parents were absent, however, feces could accumulate in the nest. To understand the mechanism by which nest sanitation is maintained, we studied the timing of defecation in nestling birds of common passerine species in southwest China. In 159 nests of 8 species at the nestling stage during 779 randomly timed observations, we never found fecal sacs present. Video recordings, totaling 455 h at five Pycnonotus jocosus nests in the field, showed almost all defecation after feedings, and only nestlings that were fed defecated. Six translocated P. jocosus nests were taken into captivity in order to manipulate the frequency of feeding. These nestlings defecated only after feeding, even when feeding intervals were extended to 60 and 120 min. The fecal sac weight also increased with extended feeding intervals, demonstrating a remarkable plasticity for nestlings to wait for feedings. The evidence allows two major conclusions: 1) defecation in the nest occurs at a time that ensures nest sanitation, stimulated by feeding, rather than there being a set time of gut processing between feeding and excretion; 2) the strong plasticity in the timing of defecation and the possibility of negative repercussions (if defecation occurs when parents are absent) are important mechanisms underlying the efficiency of the feeding-defecation system.

  15. Copernicus observations of Betelgeuse and Antares

    NASA Technical Reports Server (NTRS)

    Bernat, A. P.; Lambert, D. L.

    1976-01-01

    The Mg II h and k lines were observed strongly in emission by Copernicus scans of the M supergiants alpha Ori and alpha Sco. The striking symmetry in the k line as contrasted with the symmetric h line, as observed previously was confirmed. Estimates of absolute chromospheric fluxes were obtained. Measured values for the widths of the h and k lines do not follow a Wilson-Bappu relationship. Upper limits determined for other chromospheric lines of alpha Ori tend to exclude the existence of extensive and/or hot regions surrounding this supergiant. Observed weakening by fluorescence of the Fe L 4307 A line is good evidence that the Mn I and Fe I resonance transitions overlying the Mg II k-line profile are responsible for the strong asymmetry of this line in the two stars. However, quantitative study shows that the absorption provided by the cool circumstellar shells is insufficient to provide the observed asymmetry. Additional absorption may be provided by a cool turbulent region at the top of the chromosphere.

  16. ALMA OBSERVATIONS OF SPT-DISCOVERED, STRONGLY LENSED, DUSTY, STAR-FORMING GALAXIES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hezaveh, Y. D.; Marrone, D. P.; Spilker, J. S.

    2013-04-20

    We present Atacama Large Millimeter/submillimeter Array (ALMA) 860 {mu}m imaging of four high-redshift (z = 2.8-5.7) dusty sources that were detected using the South Pole Telescope (SPT) at 1.4 mm and are not seen in existing radio to far-infrared catalogs. At 1.''5 resolution, the ALMA data reveal multiple images of each submillimeter source, separated by 1''-3'', consistent with strong lensing by intervening galaxies visible in near-IR imaging of these sources. We describe a gravitational lens modeling procedure that operates on the measured visibilities and incorporates self-calibration-like antenna phase corrections as part of the model optimization, which we use to interpretmore » the source structure. Lens models indicate that SPT0346-52, located at z = 5.7, is one of the most luminous and intensely star-forming sources in the universe with a lensing corrected FIR luminosity of 3.7 Multiplication-Sign 10{sup 13} L{sub Sun} and star formation surface density of 4200 M{sub Sun} yr{sup -1} kpc{sup -2}. We find magnification factors of 5 to 22, with lens Einstein radii of 1.''1-2.''0 and Einstein enclosed masses of 1.6-7.2 Multiplication-Sign 10{sup 11} M{sub Sun }. These observations confirm the lensing origin of these objects, allow us to measure their intrinsic sizes and luminosities, and demonstrate the important role that ALMA will play in the interpretation of lensed submillimeter sources.« less

  17. High-Density SNP Screening of the Major Histocompatibility Complex in Systemic Lupus Erythematosus Demonstrates Strong Evidence for Independent Susceptibility Regions

    PubMed Central

    Barcellos, Lisa F.; May, Suzanne L.; Ramsay, Patricia P.; Quach, Hong L.; Lane, Julie A.; Nititham, Joanne; Noble, Janelle A.; Taylor, Kimberly E.; Quach, Diana L.; Chung, Sharon A.; Kelly, Jennifer A.; Moser, Kathy L.; Behrens, Timothy W.; Seldin, Michael F.; Thomson, Glenys; Harley, John B.; Gaffney, Patrick M.; Criswell, Lindsey A.

    2009-01-01

    A substantial genetic contribution to systemic lupus erythematosus (SLE) risk is conferred by major histocompatibility complex (MHC) gene(s) on chromosome 6p21. Previous studies in SLE have lacked statistical power and genetic resolution to fully define MHC influences. We characterized 1,610 Caucasian SLE cases and 1,470 parents for 1,974 MHC SNPs, the highly polymorphic HLA-DRB1 locus, and a panel of ancestry informative markers. Single-marker analyses revealed strong signals for SNPs within several MHC regions, as well as with HLA-DRB1 (global p = 9.99×10−16). The most strongly associated DRB1 alleles were: *0301 (odds ratio, OR = 2.21, p = 2.53×10−12), *1401 (OR = 0.50, p = 0.0002), and *1501 (OR = 1.39, p = 0.0032). The MHC region SNP demonstrating the strongest evidence of association with SLE was rs3117103, with OR = 2.44 and p = 2.80×10−13. Conditional haplotype and stepwise logistic regression analyses identified strong evidence for association between SLE and the extended class I, class I, class III, class II, and the extended class II MHC regions. Sequential removal of SLE–associated DRB1 haplotypes revealed independent effects due to variation within OR2H2 (extended class I, rs362521, p = 0.006), CREBL1 (class III, rs8283, p = 0.01), and DQB2 (class II, rs7769979, p = 0.003, and rs10947345, p = 0.0004). Further, conditional haplotype analyses demonstrated that variation within MICB (class I, rs3828903, p = 0.006) also contributes to SLE risk independent of HLA-DRB1*0301. Our results for the first time delineate with high resolution several MHC regions with independent contributions to SLE risk. We provide a list of candidate variants based on biologic and functional considerations that may be causally related to SLE risk and warrant further investigation. PMID:19851445

  18. Pervasive faint Fe XIX emission from a solar active region observed with EUNIS-13: Evidence for nanoflare heating

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brosius, Jeffrey W.; Daw, Adrian N.; Rabin, D. M., E-mail: Jeffrey.W.Brosius@nasa.gov

    2014-08-01

    We present spatially resolved EUV spectroscopic measurements of pervasive, faint Fe XIX 592.2 Å line emission in an active region observed during the 2013 April 23 flight of the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS-13) sounding rocket instrument. With cooled detectors, high sensitivity, and high spectral resolution, EUNIS-13 resolves the lines of Fe XIX at 592.2 Å (formed at temperature T ≈ 8.9 MK) and Fe XII at 592.6 Å (T ≈ 1.6 MK). The Fe XIX line emission, observed over an area in excess of 4920 arcsec{sup 2} (2.58 × 10{sup 9} km{sup 2}, more than 60% of themore » active region), provides strong evidence for the nanoflare heating model of the solar corona. No GOES events occurred in the region less than 2 hr before the rocket flight, but a microflare was observed north and east of the region with RHESSI and EUNIS during the flight. The absence of significant upward velocities anywhere in the region, particularly the microflare, indicates that the pervasive Fe XIX emission is not propelled outward from the microflare site, but is most likely attributed to localized heating (not necessarily due to reconnection) consistent with the nanoflare heating model of the solar corona. Assuming ionization equilibrium we estimate Fe XIX/Fe XII emission measure ratios of ∼0.076 just outside the AR core and ∼0.59 in the core.« less

  19. Evidence of the Solar EUV Hot Channel as a Magnetic Flux Rope from Remote-sensing and In Situ Observations

    NASA Astrophysics Data System (ADS)

    SONG, H. Q.; CHEN, Y.; ZHANG, J.; CHENG, X.; Wang, B.; HU, Q.; LI, G.; WANG, Y. M.

    2015-07-01

    Hot channels (HCs), high-temperature erupting structures in the lower corona of the Sun, have been proposed as a proxy of magnetic flux ropes (MFRs) since their initial discovery. However, it is difficult to provide definitive proof given the fact that there is no direct measurement of the magnetic field in the corona. An alternative method is to use the magnetic field measurement in the solar wind from in situ instruments. On 2012 July 12, an HC was observed prior to and during a coronal mass ejection (CME) by the Atmospheric Imaging Assembly high-temperature images. The HC is invisible in the EUVI low-temperature images, which only show the cooler leading front (LF). However, both the LF and an ejecta can be observed in the coronagraphic images. These are consistent with the high temperature and high density of the HC and support that the ejecta is the erupted HC. Meanwhile, the associated CME shock was identified ahead of the ejecta and the sheath through the COR2 images, and the corresponding ICME was detected by the Advanced Composition Explorer, showing the shock, sheath, and magnetic cloud (MC) sequentially, which agrees with the coronagraphic observations. Further, the MC average Fe charge state is elevated, containing a relatively low-ionization-state center and a high-ionization-state shell, consistent with the preexisting HC observation and its growth through magnetic reconnection. All of these observations support that the MC detected near the Earth is the counterpart of the erupted HC in the corona for this event. The study provides strong observational evidence of the HC as an MFR.

  20. Evidence of the Solar EUV Hot Channel as a Magnetic Flux Rope from Remote-sensing and in situ Observations

    NASA Astrophysics Data System (ADS)

    Song, H.

    2015-12-01

    Hot channels (HCs), high-temperature erupting structures in the lower corona of the Sun, have been proposed as a proxy of magnetic flux ropes (MFRs) since their initial discovery. However, it is difficult to provide definitive proof given the fact that there is no direct measurement of the magnetic field in the corona. An alternative method is to use the magnetic field measurement in the solar wind from in situ instruments. On 2012 July 12, an HC was observed prior to and during a coronal mass ejection (CME) by the Atmospheric Imaging Assembly high-temperature images. The HC is invisible in the EUVI low-temperature images, which only show the cooler leading front (LF). However, both the LF and an ejecta can be observed in the coronagraphic images. These are consistent with the high temperature and high density of the HC and support that the ejecta is the erupted HC. Meanwhile, the associated CME shock was identified ahead of the ejecta and the sheath through the COR2 images, and the corresponding ICME was detected by the Advanced Composition Explorer, showing the shock, sheath, and magnetic cloud (MC) sequentially, which agrees with the coronagraphic observations. Further, the MC average Fe charge state is elevated, containing a relatively low-ionization-state center and a high-ionization-state shell, consistent with the preexisting HC observation and its growth through magnetic reconnection. All of these observations support that the MC detected near the Earth is the counterpart of the erupted HC in the corona for this event. The study provides strong observational evidence of the HC as an MFR.

  1. Observation and confirmation of six strong-lensing systems in the Dark Energy Survey science verification data

    DOE PAGES

    Nord, B.; Buckley-Geer, E.; Lin, H.; ...

    2016-08-05

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either weremore » not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ~ 0.80–3.2 and in i-band surface brightness i SB ~ 23–25 mag arcsec –2 (2'' aperture). For each of the six systems, we estimate the Einstein radius θ E and the enclosed mass M enc, which have ranges θ E ~ 5''–9'' and M enc ~ 8 × 10 12 to 6 × 10 13 M ⊙, respectively.« less

  2. Observation and confirmation of six strong-lensing systems in the Dark Energy Survey science verification data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nord, B.; Buckley-Geer, E.; Lin, H.

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either weremore » not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ~ 0.80–3.2 and in i-band surface brightness i SB ~ 23–25 mag arcsec –2 (2'' aperture). For each of the six systems, we estimate the Einstein radius θ E and the enclosed mass M enc, which have ranges θ E ~ 5''–9'' and M enc ~ 8 × 10 12 to 6 × 10 13 M ⊙, respectively.« less

  3. Engineering applications of strong ground motion simulation

    NASA Astrophysics Data System (ADS)

    Somerville, Paul

    1993-02-01

    design response spectra for crustal earthquakes at a power plant site in California and for subduction earthquakes in the Seattle-Portland region. We also demonstrate the use of simulation methods for modeling the attenuation of strong ground motion, and show evidence of the effect of critical reflections from the lower crust in causing the observed flattening of the attenuation of strong ground motion from the 1988 Saguenay, Quebec, and 1989 Loma Prieta earthquakes.

  4. The disagreement between the ideal observer and human observers in hardware and software imaging system optimization: theoretical explanations and evidence

    NASA Astrophysics Data System (ADS)

    He, Xin

    2017-03-01

    The ideal observer is widely used in imaging system optimization. One practical question remains open: do the ideal and human observers have the same preference in system optimization and evaluation? Based on the ideal observer's mathematical properties proposed by Barrett et. al. and the empirical properties of human observers investigated by Myers et. al., I attempt to pursue the general rules regarding the applicability of the ideal observer in system optimization. Particularly, in software optimization, the ideal observer pursues data conservation while humans pursue data presentation or perception. In hardware optimization, the ideal observer pursues a system with the maximum total information, while humans pursue a system with the maximum selected (e.g., certain frequency bands) information. These different objectives may result in different system optimizations between human and the ideal observers. Thus, an ideal observer optimized system is not necessarily optimal for humans. I cite empirical evidence in search and detection tasks, in hardware and software evaluation, in X-ray CT, pinhole imaging, as well as emission computed tomography to corroborate the claims. (Disclaimer: the views expressed in this work do not necessarily represent those of the FDA)

  5. J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Suyu, S.; Schrabback, T.; Hildebrandt, H.; Erben, T.; Halkola, A.

    2010-05-01

    Aims: We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. Methods: We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data. Results: J0454 is located at z = 0.26, with a gap of 2.5 mag between the brightest and second brightest galaxies within half the virial radius. Outside a radius of 1.5 Mpc, we find two filaments extending over 4 Mpc, and within we identify 31 members spectroscopically and 33 via the red sequence with i < 22 mag. They segregate into spirals (σ_v = 590 km s-1) and a central concentration of ellipticals (σ_v = 480 km s-1), establishing a morphology-density relation. Weak lensing and cluster richness relations yield consistent values of r200 = 810-850 kpc and M200 = (0.75-0.90) × 1014 M_⊙. The brightest group galaxy (BGG) is inconsistent with the dynamic centre of J0454. It strongly lenses a galaxy at z = 2.1 ± 0.3, and we model the lens with a pseudo-isothermal elliptical mass distribution. A high external shear, and a discrepancy between the Einstein radius and the weak lensing velocity dispersion requires that the BGG must be offset from J0454's dark halo centre by at least 90-130 kpc. The X-ray halo is offset by 24 ± 16 kpc from the BGG, shows no signs of a cooling flow and can be fit by a single β-model. With LX = (1.4 ± 0.2) × 1043 erg s-1 J0454

  6. Dynamics of bleomycin interaction with a strongly bound hairpin DNA substrate, and implications for cleavage of the bound DNA.

    PubMed

    Bozeman, Trevor C; Nanjunda, Rupesh; Tang, Chenhong; Liu, Yang; Segerman, Zachary J; Zaleski, Paul A; Wilson, W David; Hecht, Sidney M

    2012-10-31

    Recent studies involving DNAs bound strongly by bleomycins have documented that such DNAs are degraded by the antitumor antibiotic with characteristics different from those observed when studying the cleavage of randomly chosen DNAs in the presence of excess Fe·BLM. In the present study, surface plasmon resonance has been used to characterize the dynamics of BLM B(2) binding to a strongly bound hairpin DNA, to define the effects of Fe(3+), salt, and temperature on BLM-DNA interaction. One strong primary DNA binding site, and at least one much weaker site, were documented. In contrast, more than one strong cleavage site was found, an observation also made for two other hairpin DNAs. Evidence is presented for BLM equilibration between the stronger and weaker binding sites in a way that renders BLM unavailable to other, less strongly bound DNAs. Thus, enhanced binding to a given site does not necessarily result in increased DNA degradation at that site; i.e., for strongly bound DNAs, the facility of DNA cleavage must involve other parameters in addition to the intrinsic rate of C-4' H atom abstraction from DNA sugars.

  7. Strong Generative Capacity and the Empirical Base of Linguistic Theory

    PubMed Central

    Ott, Dennis

    2017-01-01

    This Perspective traces the evolution of certain central notions in the theory of Generative Grammar (GG). The founding documents of the field suggested a relation between the grammar, construed as recursively enumerating an infinite set of sentences, and the idealized native speaker that was essentially equivalent to the relation between a formal language (a set of well-formed formulas) and an automaton that recognizes strings as belonging to the language or not. But this early view was later abandoned, when the focus of the field shifted to the grammar's strong generative capacity as recursive generation of hierarchically structured objects as opposed to strings. The grammar is now no longer seen as specifying a set of well-formed expressions and in fact necessarily constructs expressions of any degree of intuitive “acceptability.” The field of GG, however, has not sufficiently acknowledged the significance of this shift in perspective, as evidenced by the fact that (informal and experimentally-controlled) observations about string acceptability continue to be treated as bona fide data and generalizations for the theory of GG. The focus on strong generative capacity, it is argued, requires a new discussion of what constitutes valid empirical evidence for GG beyond observations pertaining to weak generation. PMID:28983268

  8. Strong monogamy conjecture in a four-qubit system

    NASA Astrophysics Data System (ADS)

    Karmakar, Sumana; Sen, Ajoy; Bhar, Amit; Sarkar, Debasis

    2016-01-01

    Monogamy is a defining feature of entanglement, having far-reaching applications. Recently, Regula et al. [Phys. Rev. Lett. 113, 110501 (2014), 10.1103/PhysRevLett.113.110501] proposed a stronger version of monogamy relation for concurrence. We have extended the strong monogamy inequality for another entanglement measure, viz., negativity. In particular, we have concentrated on the four-qubit system and provided a detailed study on the status of strong monogamy on pure states. Further, we have analytically provided some classes of states for which negativity and squared negativity satisfy strong monogamy. Numerical evidences have also been shown in proper places. Our analysis also provides cases where strong monogamy is violated.

  9. Strong plume fluxes at Mars observed by MAVEN: An important planetary ion escape channel

    NASA Astrophysics Data System (ADS)

    Dong, Y.; Fang, X.; Brain, D. A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E.; Curry, S. M.; Harada, Y.; Luhmann, J. G.; Jakosky, B. M.

    2015-11-01

    We present observations by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission of a substantial plume-like distribution of escaping ions from the Martian atmosphere, organized by the upstream solar wind convection electric field. From a case study of MAVEN particle-and-field data during one spacecraft orbit, we identified three escaping planetary ion populations: plume fluxes mainly along the upstream electric field over the north pole region of the Mars-Sun-Electric field (MSE) coordinate system, antisunward ion fluxes in the tail region, and much weaker upstream pickup ion fluxes. A statistical study of O+ fluxes using 3 month MAVEN data shows that the plume is a constant structure with strong fluxes widely distributed in the MSE northern hemisphere, which constitutes an important planetary ion escape channel. The escape rate through the plume is estimated to be ~30% of the tailward escape and ~23% of the total escape for > 25 eV O+ ions.

  10. Use of acetaminophen and risk of endometrial cancer: evidence from observational studies.

    PubMed

    Ding, Yuan-Yuan; Yao, Peng; Verma, Surya; Han, Zhen-Kai; Hong, Tao; Zhu, Yong-Qiang; Li, Hong-Xi

    2017-05-23

    Previous meta-analyses suggested that aspirin was associated with reduced risk of endometrial cancer. However, there has been no study comprehensively summarize the evidence of acetaminophen use and risk of endometrial cancer from observational studies. We systematically searched electronic databases (PubMed , EMBASE, Web of Science, and Cochrane Library) for relevant cohort or case-control studies up to February 28, 2017. Two independent authors performed the eligibility evaluation and data extraction. All differences were resolved by discussion. A random-effects model was applied to estimate summary relative risks (RRs) with 95% CIs. All statistical tests were two-sided. Seven observational studies including four prospective cohort studies and three case-control studies with 3874 endometrial cancer cases were included for final analysis. Compared with never use acetaminophen, ever use this drug was not associated with risk of endometrial cancer (summarized RR = 1.02; 95% CI: 0.93-1.13, I2 = 0%). Similar null association was also observed when compared the highest category of frequency/duration with never use acetaminophen (summarized RR = 0.88; 95% CI: 0.70-1.11, I2 = 15.2%). Additionally, the finding was robust in the subgroup analyses stratified by study characteristics and adjustment for potential confounders and risk factors. There was no evidence of publication bias by a visual inspection of a funnel plot and formal statistical tests. In summary, the present meta-analysis reveals no association between acetaminophen use and risk of endometrial cancer. More large scale prospective cohort studies are warranted to confirm our findings and carry out the dose-response analysis of aforementioned association.

  11. OBSERVATION AND CONFIRMATION OF SIX STRONG-LENSING SYSTEMS IN THE DARK ENERGY SURVEY SCIENCE VERIFICATION DATA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nord, B.; Buckley-Geer, E.; Lin, H.

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either weremore » not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ∼ 0.80–3.2 and in i -band surface brightness i {sub SB} ∼ 23–25 mag arcsec{sup −2} (2″ aperture). For each of the six systems, we estimate the Einstein radius θ {sub E} and the enclosed mass M {sub enc}, which have ranges θ {sub E} ∼ 5″–9″ and M {sub enc} ∼ 8 × 10{sup 12} to 6 × 10{sup 13} M {sub ⊙}, respectively.« less

  12. Observation and Confirmation of Six Strong-lensing Systems in the Dark Energy Survey Science Verification Data

    NASA Astrophysics Data System (ADS)

    Nord, B.; Buckley-Geer, E.; Lin, H.; Diehl, H. T.; Helsby, J.; Kuropatkin, N.; Amara, A.; Collett, T.; Allam, S.; Caminha, G. B.; De Bom, C.; Desai, S.; Dúmet-Montoya, H.; Pereira, M. Elidaiana da S.; Finley, D. A.; Flaugher, B.; Furlanetto, C.; Gaitsch, H.; Gill, M.; Merritt, K. W.; More, A.; Tucker, D.; Saro, A.; Rykoff, E. S.; Rozo, E.; Birrer, S.; Abdalla, F. B.; Agnello, A.; Auger, M.; Brunner, R. J.; Carrasco Kind, M.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Foley, R. J.; Gerdes, D. W.; Glazebrook, K.; Gschwend, J.; Hartley, W.; Kessler, R.; Lagattuta, D.; Lewis, G.; Maia, M. A. G.; Makler, M.; Menanteau, F.; Niernberg, A.; Scolnic, D.; Vieira, J. D.; Gramillano, R.; Abbott, T. M. C.; Banerji, M.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carretero, J.; D'Andrea, C. B.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Frieman, J.; Gaztanaga, E.; Gruen, D.; Honscheid, K.; James, D. J.; Kuehn, K.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miquel, R.; Neilsen, E.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Walker, A. R.; Wester, W.; Zhang, Y.; DES Collaboration

    2016-08-01

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either were not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ˜ 0.80-3.2 and in I-band surface brightness I SB ˜ 23-25 mag arcsec-2 (2″ aperture). For each of the six systems, we estimate the Einstein radius θ E and the enclosed mass M enc, which have ranges θ E ˜ 5″-9″ and M enc ˜ 8 × 1012 to 6 × 1013 M ⊙, respectively. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  13. Observational learning without a model is influenced by the observer's possibility to act: evidence from the Simon task.

    PubMed

    Iani, Cristina; Rubichi, Sandro; Ferraro, Luca; Nicoletti, Roberto; Gallese, Vittorio

    2013-07-01

    We assessed whether observational learning in perceptual-motor tasks is affected by the visibility of an action producing perceived environmental effects and by the observer's possibility to act during observation. To this end, we conducted three experiments in which participants were required to observe a spatial compatibility task in which only the effects of computer-generated responses were visible before executing a Simon task. In Experiment 1, we compared the effects of a passively observed practice with either a spatially compatible or incompatible stimulus-response (S-R) association. In Experiment 2, during the observed spatially incompatible practice participants were prevented from potentially acting, either because a plexiglas barrier separated the participant from the response device rendering it out of reach; or because the participant's hands were tied; or the device affording a response was absent. In Experiment 3, the plexiglas presented an opening that could allow the participant to potentially reach and interact with it. As when the practice is physically performed, we found an elimination of the Simon effect following a spatially incompatible observed practice, suggesting that participants learned an incompatible S-R association by observing and transferred this knowledge to the subsequent Simon task. No evidence of transfer of learning was found when, during passive observation, the participant's hands were tied, or a barrier prevented him/her from potentially interacting with the device, or no response device was present. Differently, a transfer-of-learning effect was observed when the barrier presented an opening. These results suggest that learning can derive from the mere observation of action effects, even when an action is not visible, as long as the observer has the potential to act. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Phylogenomics provides strong evidence for relationships of butterflies and moths.

    PubMed

    Kawahara, Akito Y; Breinholt, Jesse W

    2014-08-07

    Butterflies and moths constitute some of the most popular and charismatic insects. Lepidoptera include approximately 160 000 described species, many of which are important model organisms. Previous studies on the evolution of Lepidoptera did not confidently place butterflies, and many relationships among superfamilies in the megadiverse clade Ditrysia remain largely uncertain. We generated a molecular dataset with 46 taxa, combining 33 new transcriptomes with 13 available genomes, transcriptomes and expressed sequence tags (ESTs). Using HaMStR with a Lepidoptera-specific core-orthologue set of single copy loci, we identified 2696 genes for inclusion into the phylogenomic analysis. Nucleotides and amino acids of the all-gene, all-taxon dataset yielded nearly identical, well-supported trees. Monophyly of butterflies (Papilionoidea) was strongly supported, and the group included skippers (Hesperiidae) and the enigmatic butterfly-moths (Hedylidae). Butterflies were placed sister to the remaining obtectomeran Lepidoptera, and the latter was grouped with greater than or equal to 87% bootstrap support. Establishing confident relationships among the four most diverse macroheteroceran superfamilies was previously challenging, but we recovered 100% bootstrap support for the following relationships: ((Geometroidea, Noctuoidea), (Bombycoidea, Lasiocampoidea)). We present the first robust, transcriptome-based tree of Lepidoptera that strongly contradicts historical placement of butterflies, and provide an evolutionary framework for genomic, developmental and ecological studies on this diverse insect order. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  15. Phylogenomics provides strong evidence for relationships of butterflies and moths

    PubMed Central

    Kawahara, Akito Y.; Breinholt, Jesse W.

    2014-01-01

    Butterflies and moths constitute some of the most popular and charismatic insects. Lepidoptera include approximately 160 000 described species, many of which are important model organisms. Previous studies on the evolution of Lepidoptera did not confidently place butterflies, and many relationships among superfamilies in the megadiverse clade Ditrysia remain largely uncertain. We generated a molecular dataset with 46 taxa, combining 33 new transcriptomes with 13 available genomes, transcriptomes and expressed sequence tags (ESTs). Using HaMStR with a Lepidoptera-specific core-orthologue set of single copy loci, we identified 2696 genes for inclusion into the phylogenomic analysis. Nucleotides and amino acids of the all-gene, all-taxon dataset yielded nearly identical, well-supported trees. Monophyly of butterflies (Papilionoidea) was strongly supported, and the group included skippers (Hesperiidae) and the enigmatic butterfly–moths (Hedylidae). Butterflies were placed sister to the remaining obtectomeran Lepidoptera, and the latter was grouped with greater than or equal to 87% bootstrap support. Establishing confident relationships among the four most diverse macroheteroceran superfamilies was previously challenging, but we recovered 100% bootstrap support for the following relationships: ((Geometroidea, Noctuoidea), (Bombycoidea, Lasiocampoidea)). We present the first robust, transcriptome-based tree of Lepidoptera that strongly contradicts historical placement of butterflies, and provide an evolutionary framework for genomic, developmental and ecological studies on this diverse insect order. PMID:24966318

  16. Strong evidence for a genetic contribution to late-onset Alzheimer's disease mortality: a population-based study.

    PubMed

    Kauwe, John S K; Ridge, Perry G; Foster, Norman L; Cannon-Albright, Lisa A

    2013-01-01

    Alzheimer's disease (AD) is an international health concern that has a devastating effect on patients and families. While several genetic risk factors for AD have been identified much of the genetic variance in AD remains unexplained. There are limited published assessments of the familiality of Alzheimer's disease. Here we present the largest genealogy-based analysis of AD to date. We assessed the familiality of AD in The Utah Population Database (UPDB), a population-based resource linking electronic health data repositories for the state with the computerized genealogy of the Utah settlers and their descendants. We searched UPDB for significant familial clustering of AD to evaluate the genetic contribution to disease. We compared the Genealogical Index of Familiality (GIF) between AD individuals and randomly selected controls and estimated the Relative Risk (RR) for a range of family relationships. Finally, we identified pedigrees with a significant excess of AD deaths. The GIF analysis showed that pairs of individuals dying from AD were significantly more related than expected. This excess of relatedness was observed for both close and distant relationships. RRs for death from AD among relatives of individuals dying from AD were significantly increased for both close and more distant relatives. Multiple pedigrees had a significant excess of AD deaths. These data strongly support a genetic contribution to the observed clustering of individuals dying from AD. This report is the first large population-based assessment of the familiality of AD mortality and provides the only reported estimates of relative risk of AD mortality in extended relatives to date. The high-risk pedigrees identified show a true excess of AD mortality (not just multiple cases) and are greater in depth and width than published AD pedigrees. The presence of these high-risk pedigrees strongly supports the possibility of rare predisposition variants not yet identified.

  17. Association Between Cannabis and Psychosis: Epidemiologic Evidence.

    PubMed

    Gage, Suzanne H; Hickman, Matthew; Zammit, Stanley

    2016-04-01

    Associations between cannabis use and psychotic outcomes are consistently reported, but establishing causality from observational designs can be problematic. We review the evidence from longitudinal studies that have examined this relationship and discuss the epidemiologic evidence for and against interpreting the findings as causal. We also review the evidence identifying groups at particularly high risk of developing psychosis from using cannabis. Overall, evidence from epidemiologic studies provides strong enough evidence to warrant a public health message that cannabis use can increase the risk of psychotic disorders. However, further studies are required to determine the magnitude of this effect, to determine the effect of different strains of cannabis on risk, and to identify high-risk groups particularly susceptible to the effects of cannabis on psychosis. We also discuss complementary epidemiologic methods that can help address these questions. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  18. Evidence for strong lateral seismic velocity variation in the lower crust and upper mantle beneath the California margin

    USGS Publications Warehouse

    Lai, Voon; Graves, Robert; Wei, Shengji; Helmberger, Don

    2017-01-01

    Regional seismograms from earthquakes in Northern California show a systematic difference in arrival times across Southern California where long period (30–50 seconds) SH waves arrive up to 15 seconds earlier at stations near the coast compared with sites towards the east at similar epicentral distances. We attribute this time difference to heterogeneity of the velocity structure at the crust-mantle interface beneath the California margin. To model these observations, we propose a fast seismic layer, with thickness growing westward from the San Andreas along with a thicker and slower continental crust to the east. Synthetics generated from such a model are able to match the observed timing of SH waveforms better than existing 3D models. The presence of a strong upper mantle buttressed against a weaker crust has a major influence in how the boundary between the Pacific plate and North American plate deforms and may explain the observed asymmetric strain rate across the boundary.

  19. Field evidence of strong differential pollen placement by Old World bat-pollinated plants

    PubMed Central

    Stewart, Alyssa B.; Dudash, Michele R.

    2017-01-01

    Background and Aims Sympatric plant species that share pollinators potentially compete for pollination and risk interspecific pollen transfer, but this competition can be minimized when plant species place pollen on different areas of the pollinator’s body. Multiple studies have demonstrated strong differential pollen placement by sympatric plant species under laboratory conditions; however, field evidence collected in natural settings is less common. Furthermore, it is unknown whether precise pollen placement on the pollinator’s body remains constant throughout the foraging period, or if such patterns become diffused over time (e.g. due to grooming). To test the prevalence of differential pollen placement in the wild, we examined a community of five night-blooming plant species in southern Thailand that share common bat pollinators. Methods We mist-netted wild foraging nectar bats and collected pollen samples from four body parts: the crown of the head, face, chest and ventral side of one wing. We also noted the time of pollen collection to assess how pollinator pollen loads change throughout the foraging period. Key Results Our findings revealed that most of our plant study species placed pollen on precise areas of the bat, consistent with experimental work, and that patterns of differential pollen placement remained constant throughout the night. Conclusions This study demonstrates how diverse floral morphologies effectively limit interspecific pollen transfer among Old World bat-pollinated plants under natural conditions. Additionally, interspecific pollen transfer is probably minimal throughout the entire foraging period, since patterns of pollen on the bats’ bodies were consistent over time. PMID:27864223

  20. Steroidal contraceptives and bone fractures in women: evidence from observational studies.

    PubMed

    Lopez, Laureen M; Chen, Mario; Mullins Long, Sarah; Curtis, Kathryn M; Helmerhorst, Frans M

    2015-07-21

    Age-related decline in bone mass increases the risk of skeletal fractures, especially those of the hip, spine, and wrist. Steroidal contraceptives have been associated with changes in bone mineral density in women. Whether such changes affect the risk of fractures later in life is unclear. Hormonal contraceptives are among the most effective and most widely-used contraceptives. Concern about fractures may limit the use of these effective contraceptives. Observational studies can collect data on premenopausal contraceptive use as well as fracture incidence later in life. We systematically reviewed the evidence from observational studies of hormonal contraceptive use for contraception and the risk of fracture in women. Through June 2015, we searched for observational studies. The databases included PubMed, POPLINE, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS, EMBASE, CINAHL, and Web of Science. We also searched for recent clinical trials through ClinicalTrials.gov and the ICTRP. For other studies, we examined reference lists of relevant articles and wrote to investigators for additional reports. We included cohort and case-control studies of hormonal contraceptive use. Interventions included comparisons of a hormonal contraceptive with a non-hormonal contraceptive, no contraceptive, or another hormonal contraceptive. The primary outcome was the risk of fracture. Two authors independently extracted the data. One author entered the data into RevMan, and a second author verified accuracy. We examined the quality of evidence using the Newcastle-Ottawa Quality Assessment Scale (NOS), developed for case-control and cohort studies. Sensitivity analysis included studies of moderate or high quality based on our assessment with the NOS.Given the need to control for confounding factors in observational studies, we used adjusted estimates from the models as reported by the authors. Where we did not have adjusted analyses, we calculated the odds ratio (OR

  1. Observations and Numerical Modelling of Strong Meteotsunami of 13 June 2013 on the East Coast of the USA

    NASA Astrophysics Data System (ADS)

    Fine, I.; Sepic, J.; Rabinovich, A.; Thomson, R.

    2014-12-01

    A strong "derecho" (rapidly moving lines of convectively induced intense thunderstorms) was generated over the Midwestern United States on 12-13 June 2013 and propagated across the Appalachian Mountains to the Atlantic Ocean. Three hours after the derecho crossed the Atlantic coast, a ~2-m high meteotsunami wave was reported to have hit the New Jersey coast. Significant tsunami-like oscillations, with wave heights of ~0.6 m, were also recorded by a number of tide-gauges located along the eastern seaboard from Nova Scotia to South Carolina, at Bermuda, and by open-ocean DART 44402. These observations triggered the tsunami-alert mode of the DART station. Intense air pressure disturbances (with pressure change of 3-6 hPa in 20 min) and strong winds were observed at a number of National Oceanic and Atmospheric Administration (NOAA) and Automated Surface Observing System (ASOS) stations to be propagating simultaneously with the derecho system, indicating that the pressure disturbances were the primary cause for the sea level oscillations in Chesapeake and Delaware bays. The air pressure disturbance continued to propagate seaward over the continental shelf, thereby generating long waves via Proudman resonance at those areas of the shelf where the propagation speed of the air pressure disturbance matched the long wave speed. Upon reaching the shelf break, the long-waves were partly transmitted (reaching Bermuda 5 hours later) and partly reflected (returning to the east coast of the US and Canada 3 to 6 hours later). A numerical barotropic ocean model forced with idealized air pressure and wind fields was used successfully to simulate the event. The meteotsunami arrival times and maximum wave heights obtained from the model closely match the measured values and confirm initial assumptions regarding the partitioning between transmitted and reflected meteotsunami waves.

  2. Strong Stackelberg reasoning in symmetric games: An experimental replication and extension

    PubMed Central

    Colman, Andrew M.; Lawrence, Catherine L.

    2014-01-01

    In common interest games in which players are motivated to coordinate their strategies to achieve a jointly optimal outcome, orthodox game theory provides no general reason or justification for choosing the required strategies. In the simplest cases, where the optimal strategies are intuitively obvious, human decision makers generally coordinate without difficulty, but how they achieve this is poorly understood. Most theories seeking to explain strategic coordination have limited applicability, or require changes to the game specification, or introduce implausible assumptions or radical departures from fundamental game-theoretic assumptions. The theory of strong Stackelberg reasoning, according to which players choose strategies that would maximize their own payoffs if their co-players could invariably anticipate any strategy and respond with a best reply to it, avoids these problems and explains strategic coordination in all dyadic common interest games. Previous experimental evidence has provided evidence for strong Stackelberg reasoning in asymmetric games. Here we report evidence from two experiments consistent with players being influenced by strong Stackelberg reasoning in a wide variety of symmetric 3 × 3 games but tending to revert to other choice criteria when strong Stackelberg reasoning generates small payoffs. PMID:24688846

  3. Strong Stackelberg reasoning in symmetric games: An experimental replication and extension.

    PubMed

    Pulford, Briony D; Colman, Andrew M; Lawrence, Catherine L

    2014-01-01

    In common interest games in which players are motivated to coordinate their strategies to achieve a jointly optimal outcome, orthodox game theory provides no general reason or justification for choosing the required strategies. In the simplest cases, where the optimal strategies are intuitively obvious, human decision makers generally coordinate without difficulty, but how they achieve this is poorly understood. Most theories seeking to explain strategic coordination have limited applicability, or require changes to the game specification, or introduce implausible assumptions or radical departures from fundamental game-theoretic assumptions. The theory of strong Stackelberg reasoning, according to which players choose strategies that would maximize their own payoffs if their co-players could invariably anticipate any strategy and respond with a best reply to it, avoids these problems and explains strategic coordination in all dyadic common interest games. Previous experimental evidence has provided evidence for strong Stackelberg reasoning in asymmetric games. Here we report evidence from two experiments consistent with players being influenced by strong Stackelberg reasoning in a wide variety of symmetric 3 × 3 games but tending to revert to other choice criteria when strong Stackelberg reasoning generates small payoffs.

  4. Evidence for magnetic Weyl fermions in a correlated metal

    NASA Astrophysics Data System (ADS)

    Kuroda, K.; Tomita, T.; Suzuki, M.-T.; Bareille, C.; Nugroho, A. A.; Goswami, P.; Ochi, M.; Ikhlas, M.; Nakayama, M.; Akebi, S.; Noguchi, R.; Ishii, R.; Inami, N.; Ono, K.; Kumigashira, H.; Varykhalov, A.; Muro, T.; Koretsune, T.; Arita, R.; Shin, S.; Kondo, Takeshi; Nakatsuji, S.

    2017-11-01

    Weyl fermions have been observed as three-dimensional, gapless topological excitations in weakly correlated, inversion-symmetry-breaking semimetals. However, their realization in spontaneously time-reversal-symmetry-breaking phases of strongly correlated materials has so far remained hypothetical. Here, we report experimental evidence for magnetic Weyl fermions in Mn3Sn, a non-collinear antiferromagnet that exhibits a large anomalous Hall effect, even at room temperature. Detailed comparison between angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations reveals significant bandwidth renormalization and damping effects due to the strong correlation among Mn 3d electrons. Magnetotransport measurements provide strong evidence for the chiral anomaly of Weyl fermions--namely, the emergence of positive magnetoconductance only in the presence of parallel electric and magnetic fields. Since weak magnetic fields (approximately 10 mT) are adequate to control the distribution of Weyl points and the large fictitious fields (equivalent to approximately a few hundred T) produced by them in momentum space, our discovery lays the foundation for a new field of science and technology involving the magnetic Weyl excitations of strongly correlated electron systems such as Mn3Sn.

  5. Strong plasma turbulence in the earth's electron foreshock

    NASA Technical Reports Server (NTRS)

    Robinson, P. A.; Newman, D. L.

    1991-01-01

    A quantitative model is developed to account for the distribution in magnitude and location of the intense plasma waves observed in the earth's electron foreshock given the observed rms levels of waves. In this model, nonlinear strong-turbulence effects cause solitonlike coherent wave packets to form and decouple from incoherent background beam-excited weak turbulence, after which they convect downstream with the solar wind while collapsing to scales as short as 100 m and fields as high as 2 V/m. The existence of waves with energy densities above the strong-turbulence wave-collapse threshold is inferred from observations from IMP 6 and ISEE 1 and quantitative agreement is found between the predicted distribution of fields in an ensemble of such wave packets and the actual field distribution observed in situ by IMP 6. Predictions for the polarization of plasma waves and the bandwidth of ion-sound waves are also consistent with the observations. It is shown that strong-turbulence effects must be incorporated in any comprehensive theory of the propagation and evolution of electron beams in the foreshock. Previous arguments against the existence of strong turbulence in the foreshock are refuted.

  6. Strong Sporadic E Occurrence Detected by Ground-Based GNSS

    NASA Astrophysics Data System (ADS)

    Sun, Wenjie; Ning, Baiqi; Yue, Xinan; Li, Guozhu; Hu, Lianhuan; Chang, Shoumin; Lan, Jiaping; Zhu, Zhengping; Zhao, Biqiang; Lin, Jian

    2018-04-01

    The ionospheric sporadic E (Es) layer has significant impact on radio wave propagation. The traditional techniques employed for Es layer observation, for example, ionosondes, are not dense enough to resolve the morphology and dynamics of Es layer in spatial distribution. The ground-based Global Navigation Satellite Systems (GNSS) technique is expected to shed light on the understanding of regional strong Es occurrence, owing to the facts that the critical frequency (foEs) of strong Es structure is usually high enough to cause pulse-like disturbances in GNSS total electron content (TEC), and a large number of GNSS receivers have been deployed all over the world. Based on the Chinese ground-based GNSS networks, including the Crustal Movement Observation Network of China and the Beidou Ionospheric Observation Network, a large-scale strong Es event was observed in the middle latitude of China. The strong Es shown as a band-like structure in the southwest-northeast direction extended more than 1,000 km. By making a comparative analysis of Es occurrences identified from the simultaneous observations by ionosondes and GNSS TEC receivers over China middle latitude statistically, we found that GNSS TEC can be well employed to observe strong Es occurrence with a threshold value of foEs, 14 MHz.

  7. New Observational Evidence of Flash Mixing on the White Dwarf Cooling Curve

    NASA Technical Reports Server (NTRS)

    Brown, T. M.; Lanz, T.; Sweigart, A. V.; Cracraft, Misty; Hubeny, Ivan; Landsman, W. B.

    2011-01-01

    Blue hook stars are a class of subluminous extreme horizontal branch stars that were discovered in UV images of the massive globular clusters w Cen and NGC 2808. These stars occupy a region of the HR diagram that is unexplained by canonical stellar evolution theory. Using new theoretical evolutionary and atmospheric models, we have shown that the blue hook stars are very likely the progeny of stars that undergo extensive internal mixing during a late helium-core flash on the white dwarf cooling curve. This "flash mixing" produces hotter-than-normal EHB stars with atmospheres significantly enhanced in helium and carbon. The larger bolometric correction, combined with the decrease in hydrogen opacity, makes these stars appear sub luminous in the optical and UV. Flash mixing is more likely to occur in stars born with a high helium abundance, due to their lower mass at the main sequence turnoff. For this reason, the phenomenon is more common in those massive globular clusters that show evidence for secondary populations enhanced in helium. However, a high helium abundance does not, by itself, explain the presence of blue hook stars in massive globular clusters. Here, we present new observational evidence for flash mixing, using recent HST observations. These include UV color-magnitude diagrams of six massive globular clusters and far-UV spectroscopy of hot subdwarfs in one of these clusters (NGC 2808).

  8. Chasing discs around O-type (proto)stars: Evidence from ALMA observations

    NASA Astrophysics Data System (ADS)

    Cesaroni, R.; Sánchez-Monge, Á.; Beltrán, M. T.; Johnston, K. G.; Maud, L. T.; Moscadelli, L.; Mottram, J. C.; Ahmadi, A.; Allen, V.; Beuther, H.; Csengeri, T.; Etoka, S.; Fuller, G. A.; Galli, D.; Galván-Madrid, R.; Goddi, C.; Henning, T.; Hoare, M. G.; Klaassen, P. D.; Kuiper, R.; Kumar, M. S. N.; Lumsden, S.; Peters, T.; Rivilla, V. M.; Schilke, P.; Testi, L.; van der Tak, F.; Vig, S.; Walmsley, C. M.; Zinnecker, H.

    2017-06-01

    Context. Circumstellar discs around massive stars could mediate the accretion onto the star from the infalling envelope, and could minimize the effects of radiation pressure. Despite such a crucial role, only a few convincing candidates have been provided for discs around deeply embedded O-type (proto)stars. Aims: In order to establish whether disc-mediated accretion is the formation mechanism for the most massive stars, we have searched for circumstellar, rotating discs around a limited sample of six luminous (>105L⊙) young stellar objects. These objects were selected on the basis of their IR and radio properties in order to maximize the likelihood of association with disc+jet systems. Methods: We used ALMA with 0.̋2 resolution to observe a large number of molecular lines typical of hot molecular cores. In this paper we limit our analysis to two disc tracers (methyl cyanide, CH3CN, and its isotopologue, 13CH3CN), and an outflow tracer (silicon monoxide, SiO). Results: We reveal many cores, although their number depends dramatically on the target. We focus on the cores that present prominent molecular line emission. In six of these a velocity gradient is seen across the core,three of which show evidence of Keplerian-like rotation. The SiO data reveal clear but poorly collimated bipolar outflow signatures towards two objects only. This can be explained if real jets are rare (perhaps short-lived) in very massive objects and/or if stellar multiplicity significantly affects the outflow structure.For all cores with velocity gradients, the velocity field is analysed through position-velocity plots to establish whether the gas is undergoing rotation with νrot ∝ R- α, as expected for Keplerian-like discs. Conclusions: Our results suggest that in three objects we are observing rotation in circumstellar discs, with three more tentative cases, and one core where no evidence for rotation is found. In all cases but one, we find that the gas mass is less than the mass of

  9. The importance of distinguishing information from evidence/observations when formulating propositions.

    PubMed

    Hicks, T; Biedermann, A; de Koeijer, J A; Taroni, F; Champod, C; Evett, I W

    2015-12-01

    The value of forensic results crucially depends on the propositions and the information under which they are evaluated. For example, if a full single DNA profile for a contemporary marker system matching the profile of Mr A is assessed, given the propositions that the DNA came from Mr A and given it came from an unknown person, the strength of evidence can be overwhelming (e.g., in the order of a billion). In contrast, if we assess the same result given that the DNA came from Mr A and given it came from his twin brother (i.e., a person with the same DNA profile), the strength of evidence will be 1, and therefore neutral, unhelpful and irrelevant(1) to the case at hand. While this understanding is probably uncontroversial and obvious to most, if not all practitioners dealing with DNA evidence, the practical precept of not specifying an alternative source with the same characteristics as the one considered under the first proposition may be much less clear in other circumstances. During discussions with colleagues and trainees, cases have come to our attention where forensic scientists have difficulty with the formulation of propositions. It is particularly common to observe that results (e.g., observations) are included in the propositions, whereas-as argued throughout this note-they should not be. A typical example could be a case where a shoe-mark with a logo and the general pattern characteristics of a Nike Air Jordan shoe is found at the scene of a crime. A Nike Air Jordan shoe is then seized at Mr A's house and control prints of this shoe compared to the mark. The results (e.g., a trace with this general pattern and acquired characteristics corresponding to the sole of Mr A's shoe) are then evaluated given the propositions 'The mark was left by Mr A's Nike Air Jordan shoe-sole' and 'The mark was left by an unknown Nike Air Jordan shoe'. As a consequence, the footwear examiner will not evaluate part of the observations (i.e., the mark presents the general

  10. Observational evidence of a long-term increase in precipitation due to urbanization effects and its implications for sustainable urban living.

    PubMed

    Wai, K M; Wang, X M; Lin, T H; Wong, M S; Zeng, S K; He, N; Ng, E; Lau, K; Wang, D H

    2017-12-01

    Although projected precipitation increases in East Asia due to future climate change have aroused concern, less attention has been paid by the scientific community and public to the potential long-term increase in precipitation due to rapid urbanization. A ten-year precipitation dataset was analysed for both a rapidly urbanized megacity and nearby suburban/rural stations in southern China. Rapid urbanization in the megacity was evident from satellite observations. A statistically significant, long-term, increasing trend of precipitation existed only at the megacity station (45.6mm per decade) and not at the other stations. The increase was attributed to thermal and dynamical modifications of the tropospheric boundary layer related to urbanization, which was confirmed by the results of our WRF-SLUCM simulations. The results also suggested that a long-term regional increase in precipitation, caused by greenhouse gas-induced climate change, for instance, was not evident within the study period. The urbanization-induced increase was found to be higher than the precipitation increase (18.3mm per decade) expected from future climate change. The direct climate impacts due to rapid urbanization is highlighted with strong implications for urban sustainable development and the planning of effective adaptation strategies for issues such as coastal defenses, mosquito-borne disease spread and heat stress mortality. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Strong anisotropy effect in an iron-based superconductor CaFe0.882Co0.118AsF

    NASA Astrophysics Data System (ADS)

    Ma, Yonghui; Ji, Qiucheng; Hu, Kangkang; Gao, Bo; Li, Wei; Mu, Gang; Xie, Xiaoming

    2017-07-01

    The anisotropy of iron-based superconductors is much smaller than that of the cuprates and that predicted by theoretical calculations. A credible understanding for this experimental fact is still lacking up to now. Here we experimentally study the magnetic-field-angle dependence of electronic resistivity in the superconducting phase of an iron-based superconductor CaFe{}0.882Co{}0.118AsF, and find the strongest anisotropy effect of the upper critical field among the iron-based superconductors based on the framework of Ginzburg-Landau theory. The evidence of the energy band structure and charge density distribution from electronic structure calculations demonstrates that the observed strong anisotropic effect mainly comes from the strong ionic bonding in between the ions of Ca2+ and F-, which weakens the interlayer coupling between the layers of FeAs and CaF. This finding provides a significant insight into the nature of the experimentally-observed strong anisotropic effect of electronic resistivity, and also paves the way for designing exotic two-dimensional artificial unconventional superconductors in the future.

  12. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.

    We report the results of our searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verication and Year 1 observations. The Science Verication data spans approximately 250 sq. deg. with median i

  13. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    DOE PAGES

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; ...

    2017-09-01

    We report the results of our searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verication and Year 1 observations. The Science Verication data spans approximately 250 sq. deg. with median i

  14. Chandra Observations of Magnetic White Dwarfs and Their Theoretical Implications

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.; Noble, M.; Porter, J. G.; Winget, D. E.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Observations of cool DA and DB white dwarfs have not yet been successful in detecting coronal X-ray emission but observations of late-type dwarfs and giants show that coronae are common for these stars. To produce coronal X-rays, a star must have dynamo-generated surface magnetic fields and a well-developed convection zone. There is strong observational evidence that the DA star LHS 1038 and the DB star GD 358 have weak and variable surface magnetic fields. Since these fields are likely to be generated by dynamo action and since both stars have well-developed convection zones, theory predicts detectable levels of coronal X-rays from these white dwarfs. However, we present analysis of Chandra observations of both stars showing no detectable X-ray emission. The derived upper limits for the X-ray fluxes provide strong constraints on theories of formation of coronae around magnetic white dwarfs.

  15. Evidence of Absence software

    USGS Publications Warehouse

    Dalthorp, Daniel; Huso, Manuela M. P.; Dail, David; Kenyon, Jessica

    2014-01-01

    Evidence of Absence software (EoA) is a user-friendly application used for estimating bird and bat fatalities at wind farms and designing search protocols. The software is particularly useful in addressing whether the number of fatalities has exceeded a given threshold and what search parameters are needed to give assurance that thresholds were not exceeded. The software is applicable even when zero carcasses have been found in searches. Depending on the effectiveness of the searches, such an absence of evidence of mortality may or may not be strong evidence that few fatalities occurred. Under a search protocol in which carcasses are detected with nearly 100 percent certainty, finding zero carcasses would be convincing evidence that overall mortality rate was near zero. By contrast, with a less effective search protocol with low probability of detecting a carcass, finding zero carcasses does not rule out the possibility that large numbers of animals were killed but not detected in the searches. EoA uses information about the search process and scavenging rates to estimate detection probabilities to determine a maximum credible number of fatalities, even when zero or few carcasses are observed.

  16. Modelling high-resolution ALMA observations of strongly lensed highly star-forming galaxies detected by Herschel

    NASA Astrophysics Data System (ADS)

    Dye, S.; Furlanetto, C.; Dunne, L.; Eales, S. A.; Negrello, M.; Nayyeri, H.; van der Werf, P. P.; Serjeant, S.; Farrah, D.; Michałowski, M. J.; Baes, M.; Marchetti, L.; Cooray, A.; Riechers, D. A.; Amvrosiadis, A.

    2018-06-01

    We have modelled ˜0.1 arcsec resolution Atacama Large Millimetre/submillimeter Array imaging of six strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Our modelling recovers mass properties of the lensing galaxies and, by determining magnification factors, intrinsic properties of the lensed submillimetre sources. We find that the lensed galaxies all have high ratios of star formation rate to dust mass, consistent with or higher than the mean ratio for high-redshift submillimetre galaxies and low-redshift ultra-luminous infrared galaxies. Source reconstruction reveals that most galaxies exhibit disturbed morphologies. Both the cleaned image plane data and the directly observed interferometric visibilities have been modelled, enabling comparison of both approaches. In the majority of cases, the recovered lens models are consistent between methods, all six having mass density profiles that are close to isothermal. However, one system with poor signal to noise shows mildly significant differences.

  17. Field evidence of strong differential pollen placement by Old World bat-pollinated plants.

    PubMed

    Stewart, Alyssa B; Dudash, Michele R

    2017-01-01

    Sympatric plant species that share pollinators potentially compete for pollination and risk interspecific pollen transfer, but this competition can be minimized when plant species place pollen on different areas of the pollinator's body. Multiple studies have demonstrated strong differential pollen placement by sympatric plant species under laboratory conditions; however, field evidence collected in natural settings is less common. Furthermore, it is unknown whether precise pollen placement on the pollinator's body remains constant throughout the foraging period, or if such patterns become diffused over time (e.g. due to grooming). To test the prevalence of differential pollen placement in the wild, we examined a community of five night-blooming plant species in southern Thailand that share common bat pollinators. We mist-netted wild foraging nectar bats and collected pollen samples from four body parts: the crown of the head, face, chest and ventral side of one wing. We also noted the time of pollen collection to assess how pollinator pollen loads change throughout the foraging period. Our findings revealed that most of our plant study species placed pollen on precise areas of the bat, consistent with experimental work, and that patterns of differential pollen placement remained constant throughout the night. This study demonstrates how diverse floral morphologies effectively limit interspecific pollen transfer among Old World bat-pollinated plants under natural conditions. Additionally, interspecific pollen transfer is probably minimal throughout the entire foraging period, since patterns of pollen on the bats' bodies were consistent over time. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Practice management: observations, issues, and empirical evidence.

    PubMed

    Wong, H M; Braithwaite, J

    2001-02-01

    The primary objective of this study is to provide objective, empirical, evidence-based practice management information. This is a hitherto under-researched area of considerable interest for both the practitioner and educator. A questionnaire eliciting a mix of structured and free text responses was administered to a random sample of 480 practitioners who are members of the American Academy of Periodontology. Potential respondents not in private practice were excluded and the next listed person substituted. The results provide demographic and descriptive information about some of the main issues and problems facing practice managers, central to which are information technology (IT), financial, people management, and marketing. Human resource and marketing management appear to represent the biggest challenges. Periodontists running practices would prefer more information, development, and support in dealing with IT, finance, marketing, and people management. The empirical evidence reported here suggests that although tailored educational programs on key management issues at both undergraduate and postgraduate levels have become ubiquitous, nevertheless some respondents seek further training opportunities. Evidence-based practice management information will be invaluable to the clinician considering strategic and marketing planning, and also for those responsible for the design and conduct of predoctoral and postdoctoral programs.

  19. If ionospheric and geomagnetic disturbances observed before strong earthquakes may result from simultaneous impact of space weather on all geospheres including solid earth

    NASA Astrophysics Data System (ADS)

    Khachikyan, Galina

    2016-07-01

    It is revealed in previous decades that ionospheric disturbances precede strong earthquakes, thus, the ionospheric precursors of strong earthquakes are now under developing [Pulinets and Boyarchuk, 2004]. Simultaneously, it is revealed that strong earthquakes may be preceded by geomagnetic disturbances as well, as a result, the geomagnetic variations, for example, in the ULF band, are considered now as precursory signals [Fraser-Smith, 1990, doi/10.1029/GL017i009p01465]. At the same time, there is currently no reliable theory nor for ionospheric or to magnetic precursors of earthquakes. Moreover, several researches have reexamined some of above results and concluded that observed magnetic disturbances before strong earthquakes could be generated by other sources, such as global magnetic activity [e.g. Campbell, 2009, doi/10.1029/2008JA013932], and that ionospheric anomalies can also be an effect of the increase of the global magnetic activity [e. g. Masci and Thomas, 2015, doi:10.1002/2015RS005734]. Taking into account such conclusions, one may suggest that the observed ionospheric and geomagnetic disturbances before strong earthquakes might be due to simultaneous influence of a space weather on the complicated surrounding system including the solid earth. This report presents some statistical results to prove such suggestion. In particular, it is shown [Khachikyan et al., 2012, doi:10.4236/ijg.2012.35109] that maximal possible earthquake magnitude (seismic potential) can be determined, in first approximation, on the base of geomagnetic Z-component measured in the Geocentric Solar Magnetosphere (GSM) coordinate system, in which the space weather impact on the earth's environment, due to reconnection of the solar wind magnetic field with the earth's magnetic field, is more ordered.

  20. Strong stellar winds.

    PubMed

    Conti, P S; McCray, R

    1980-04-04

    The hottest and most luminous stars lose a substantial fraction of their mass in strong stellar winds. These winds not only affect the evolution of the star, they also carve huge expanding cavities in the surrounding interstellar medium, possibly affecting star formation. The winds are probably driven by radiation pressure, but uncertainties persist in their theoretical description. Strong x-ray sources associated with a few of these hot stars may be used to probe the stellar winds. The nature of the weak x-ray sources recently observed to be associated with many of these stars is uncertain. It is suggested that roughly 10 percent of the luminous hot stars may have as companions neutron stars or black holes orbiting within the stellar winds.

  1. Observational Evidence of Shallow Origins for the Magnetic Fields of Solar Cycles - a review

    NASA Astrophysics Data System (ADS)

    Martin, Sara F.

    2018-05-01

    Observational evidence for the origin of active region magnetic fields has been sought from published information on extended solar cycles, statistical distributions of active regions and ephemeral regions, helioseismology results, positional relationships to supergranules, and fine-scale magnetic structure of active regions and their sunspots during their growth. Statistical distributions of areas of ephemeral and active regions blend together to reveal a single power law. The shape of the size distribution in latitude of all active regions is independent of time during the solar cycle, yielding further evidence that active regions of all sizes belong to the same population. Elementary bipoles, identified also by other names, appear to be the building blocks of active regions; sunspots form from elementary bipoles and are therefore deduced to develop from the photosphere downward, consistent with helioseismic detection of downflows to 3-4 Mm below sunspots as well as long-observed downflows from chromospheric/coronal arch filaments into sunspots from their earliest appearance. Time-distance helioseismology has been effective in revealing flows related to sunspots to depths of 20 Mm. Ring diagram analysis shows a statistically significant preference for upflows to precede major active region emergence and downflows after flux emergence but both are often observed together or sometimes not detected. From deep-focus helioseismic techniques for seeking magnetic flux below the photosphere prior major active regions, there is evidence of acoustic travel-time perturbation signatures rising in the limited range of depths of 42-75 Mm but these have not been verified or found at more shallow depths by helioseismic holographic techniques. The development of active regions from clusters of elementary bipoles appears to be the same irrespective of how much flux an active region eventually develops. This property would be consistent with the magnetic fields of large active

  2. UpToDate adherence to GRADE criteria for strong recommendations: an analytical survey

    PubMed Central

    Merglen, Arnaud; Heen, Anja Fog; Kristiansen, Annette; Neumann, Ignacio; Brito, Juan P; Brignardello-Petersen, Romina; Alexander, Paul E; Rind, David M; Vandvik, Per O; Guyatt, Gordon H

    2017-01-01

    Introduction UpToDate is widely used by clinicians worldwide and includes more than 9400 recommendations that apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. GRADE guidance warns against strong recommendations when certainty of the evidence is low or very low (discordant recommendations) but has identified five paradigmatic situations in which discordant recommendations may be justified. Objectives Our objective was to document the strength of recommendations in UpToDate and assess the frequency and appropriateness of discordant recommendations. Design Analytical survey of all recommendations in UpToDate. Methods We identified all GRADE recommendations in UpToDate and examined their strength (strong or weak) and certainty of the evidence (high, moderate or low certainty). We identified all discordant recommendations as of January 2015, and pairs of reviewers independently classified them either into one of the five appropriate paradigms or into one of three categories inconsistent with GRADE guidance, based on the evidence presented in UpToDate. Results UpToDate included 9451 GRADE recommendations, of which 6501 (68.8%) were formulated as weak recommendations and 2950 (31.2%) as strong. Among the strong, 844 (28.6%) were based on high certainty in effect estimates, 1740 (59.0%) on moderate certainty and 366 (12.4%) on low certainty. Of the 349 discordant recommendations 204 (58.5%) were judged appropriately (consistent with one of the five paradigms); we classified 47 (13.5%) as good practice statements; 38 (10.9%) misclassified the evidence as low certainty when it was at least moderate and 60 (17.2%) warranted a weak rather than a strong recommendation. Conclusion The proportion of discordant recommendations in UpToDate is small (3.7% of all recommendations) and the proportion that is truly problematic (strong recommendations that would best have been weak) is very small (0.6%). Clinicians should nevertheless be

  3. Strong evidence for ZZ production in pp[over] collisions at sqrt[s]=1.96 TeV.

    PubMed

    Aaltonen, T; Adelman, J; Akimoto, T; Albrow, M G; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Bednar, P; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'Orso, M; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Giagu, S; Giakoumopolou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Koay, S A; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lu, R-S; Lucchesi, D; Lueck, J; Luci, C; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner-Kuhr, J; Wagner, W; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S; Group, R C

    2008-05-23

    We report the first evidence of Z boson pair production at a hadron collider with a significance exceeding 4 standard deviations. This result is based on a data sample corresponding to 1.9 fb(-1) of integrated luminosity from pp[over] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II detector. In the lll'l' channel, we observe three ZZ candidates with an expected background of 0.096(-0.063)+0.092 events. In the llnunu channel, we use a leading-order calculation of the relative ZZ and WW event probabilities to discriminate between signal and background. In the combination of lll'l' and llnunu channels, we observe an excess of events with a probability of 5.1 x 10(-6) to be due to the expected background. This corresponds to a significance of 4.4 standard deviations. The measured cross section is sigma(pp[over]-->ZZ)=1.4(-0.6)+0.7(stat+syst) pb, consistent with the standard model expectation.

  4. Secular Evolution in Barred Galaxies: Observations

    NASA Astrophysics Data System (ADS)

    Merrifield, M.

    2002-12-01

    This paper describes a framework for studying galaxy morphology, particularly bar strength, in a quantitative manner, and presents applications of this approach that reveal observational evidence for secular evolution in bar morphology. The distribution of bar strength in galaxies is quite strongly bimodal, suggesting that barred and unbarred systems are distinct entities, and that any evolution between these two states must occur on a relatively rapid timescale. Bars' strengths appear to be correlated with their pattern speeds, implying that these structures weaken as they start to slow, and disappear entirely before the bars have slowed significantly. There is also tantalizing evidence that bars are rare beyond a redshift of z ~ 0.7, indicating that galaxies have only recently evolved to a point where bars can readily form.

  5. Observational Evidence of Magnetic Reconnection for Brightenings and Transition Region Arcades in IRIS Observations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhao, Jie; Li, Hui; Feng, Li

    By using a new method of forced-field extrapolation, we study the emerging flux region AR11850 observed by the Interface Region Imaging Spectrograph and Solar Dynamical Observatory . Our results suggest that the bright points (BPs) in this emerging region exhibit responses in lines formed from the upper photosphere to the transition region, which have relatively similar morphologies. They have an oscillation of several minutes according to the Atmospheric Imaging Assembly data at 1600 and 1700 Å. The ratio between the BP intensities measured in 1600 and 1700 Å filtergrams reveals that these BPs are heated differently. Our analysis of themore » Helioseismic and Magnetic Imager vector magnetic field and the corresponding topology in AR11850 indicates that the BPs are located at the polarity inversion line and most of them are related to magnetic reconnection or cancelation. The heating of the BPs might be different due to different magnetic topology. We find that the heating due to the magnetic cancelation would be stronger than the case of bald patch reconnection. The plasma density rather than the magnetic field strength could play a dominant role in this process. Based on physical conditions in the lower atmosphere, our forced-field extrapolation shows consistent results between the bright arcades visible in slit-jaw image 1400 Å and the extrapolated field lines that pass through the bald patches. It provides reliable observational evidence for testing the mechanism of magnetic reconnection for the BPs and arcades in the emerging flux region, as proposed in simulation studies.« less

  6. Temperature-tunable Fano resonance induced by strong coupling between Weyl fermions and phonons in TaAs

    DOE PAGES

    Xu, Bing; Dai, Yaomin M.; Zhao, Lingxiao X.; ...

    2017-03-30

    Strong coupling between discrete phonon and continuous electron–hole pair excitations can induce a pronounced asymmetry in the phonon line shape, known as the Fano resonance. This effect has been observed in various systems. We reveal explicit evidence for strong coupling between an infrared-active phonon and electronic transitions near the Weyl points through the observation of a Fano resonance in the Weyl semimetal TaAs. The resulting asymmetry in the phonon line shape, conspicuous at low temperatures, diminishes continuously with increasing temperature. Furthermore, this behaviour originates from the suppression of electronic transitions near the Weyl points due to the decreasing occupation ofmore » electronic states below the Fermi level (EF) with increasing temperature, as well as Pauli blocking caused by thermally excited electrons above EF. These findings not only elucidate the mechanism governing the tunable Fano resonance but also open a route for exploring exotic physical phenomena through phonon properties in Weyl semimetals.« less

  7. On Alfvenic Waves and Stochastic Ion Heating with 1Re Observations of Strong Field-aligned Currents, Electric Fields, and O+ ions

    NASA Technical Reports Server (NTRS)

    Coffey, Victoria; Chandler, Michael; Singh, Nagendra

    2008-01-01

    The role that the cleft/cusp has in ionosphere/magnetosphere coupling makes it a very dynamic region having similar fundamental processes to those within the auroral regions. With Polar passing through the cusp at 1 Re in the Spring of 1996, we observe a strong correlation between ion heating and broadband ELF (BBELF) emissions. This commonly observed relationship led to the study of the coupling of large field-aligned currents, burst electric fields, and the thermal O+ ions. We demonstrate the role of these measurements to Alfvenic waves and stochastic ion heating. Finally we will show the properties of the resulting density cavities.

  8. Strong-field and attosecond physics in solids

    DOE PAGES

    Ghimire, Shambhu; Ndabashimiye, Georges; DiChiara, Anthony D.; ...

    2014-10-08

    We review the status of strong-field and attosecond processes in bulk transparent solids near the Keldysh tunneling limit. For high enough fields and low-frequency excitations, the optical and electronic properties of dielectrics can be transiently and reversibly modified within the applied pulse. In Ghimire et al (2011 Phys. Rev. Lett. 107 167407) non-parabolic band effects were seen in photon-assisted tunneling experiments in ZnO crystals in a strong mid-infrared field. Using the same ZnO crystals, Ghimire et al (2011 Nat. Phys. 7 138–41) reported the first observation of non-pertubative high harmonics, extending well above the bandgap into the vacuum ultraviolet. Recent experiments by Schubert et al (2014 Nat. Photonics 8 119–23) showed a carrier envelope phase dependence in the harmonic spectrum in strong-field 30 THz driven GaSe crystals which is the most direct evidence yet of the role of sub-cycle electron dynamics in solid-state harmonic generation. The harmonic generation mechanism is different from the gas phase owing to the high density and periodicity of the crystal. For example, this results in a linear dependence of the high-energy cutoff with the applied field in contrast to the quadratic dependence in the gas phase. Sub-100 attosecond pulses could become possible if the harmonic spectrum can be extended into the extreme ultraviolet (XUV). Here we report harmonics generated in bulk MgO crystals, extending tomore » $$\\sim 26$$ eV when driven by ~35 fs, 800 nm pulses focused to a ~1 VÅ$$^{-1}$$ peak field. The fundamental strong-field and attosecond response also leads to Wannier–Stark localization and reversible semimetallization as seen in the sub-optical cycle behavior of XUV absorption and photocurrent experiments on fused silica by Schiffrin et al (2013 Nature 493 70–4) and Schultze et al (2013 Nature 493 75–8). These studies are advancing our understanding of fundamental strong-field and attosecond physics in solids with potential

  9. Strongly correlated surface states

    NASA Astrophysics Data System (ADS)

    Alexandrov, Victor A.

    Everything has an edge. However trivial, this phrase has dominated theoretical condensed matter in the past half a decade. Prior to that, questions involving the edge considered to be more of an engineering problem rather than a one of fundamental science: it seemed self-evident that every edge is different. However, recent advances proved that many surface properties enjoy a certain universality, and moreover, are 'topologically' protected. In this thesis I discuss a selected range of problems that bring together topological properties of surface states and strong interactions. Strong interactions alone can lead to a wide spectrum of emergent phenomena: from high temperature superconductivity to unconventional magnetic ordering; interactions can change the properties of particles, from heavy electrons to fractional charges. It is a unique challenge to bring these two topics together. The thesis begins by describing a family of methods and models with interactions so high that electrons effectively disappear as particles and new bound states arise. By invoking the AdS/CFT correspondence we can mimic the physical systems of interest as living on the surface of a higher dimensional universe with a black hole. In a specific example we investigate the properties of the surface states and find helical spin structure of emerged particles. The thesis proceeds from helical particles on the surface of black hole to a surface of samarium hexaboride: an f-electron material with localized magnetic moments at every site. Interactions between electrons in the bulk lead to insulating behavior, but the surfaces found to be conducting. This observation motivated an extensive research: weather the origin of conduction is of a topological nature. Among our main results, we confirm theoretically the topological properties of SmB6; introduce a new framework to address similar questions for this type of insulators, called Kondo insulators. Most notably we introduce the idea of Kondo

  10. Starting Strong: Feasibility of an Indicated Prevention Programme during the Transition to Kindergarten

    ERIC Educational Resources Information Center

    Eisenhower, Abbey; Baker, Bruce L.; Taylor, Heather

    2016-01-01

    School-based mental health services are a promising context for evidence-based interventions to promote early socio-emotional development, yet implementation presents significant challenges. This paper describes the rationale, content and format of a school-based intervention, Starting Strong in Kindergarten (Starting Strong). Starting Strong is a…

  11. Nike Experiment to Observe Strong Areal Mass Oscillations in a Rippled Target Hit by a Short Laser Pulse

    NASA Astrophysics Data System (ADS)

    Aglitskiy, Y.; Karasik, M.; Velikovich, A. L.; Serlin, V.; Weaver, J. L.; Kessler, T. J.; Schmitt, A. J.; Obenschain, S. P.; Metzler, N.; Oh, J.

    2010-11-01

    When a short (sub-ns) laser pulse deposits finite energy in a target, the shock wave launched into it is immediately followed by a rarefaction wave. If the irradiated surface is rippled, theory and simulations predict strong oscillations of the areal mass perturbation amplitude in the target [A. L. Velikovich et al., Phys. Plasmas 10, 3270 (2003).] The first experiment designed to observe this effect has become possible by adding short-driving-pulse capability to the Nike laser, and has been scheduled for the fall of 2010. Simulations show that while the driving pulse of 0.3 ns is on, the areal mass perturbation amplitude grows by a factor ˜2 due to ablative Richtmyer-Meshkov instability. It then decreases, reverses phase, and reaches another maximum, also about twice its initial value, shortly after the shock breakout at the rear target surface. This signature behavior is observable with the monochromatic x-ray imaging diagnostics fielded on Nike.

  12. Strong Libraries, Strong Scores

    ERIC Educational Resources Information Center

    Gray, Carlyn

    2006-01-01

    This article talks about the first-ever Texas Conference on School Libraries on April 6, 2005 that was attended by one hundred thirty-five school administrators and trustees. The miniconference, entitled Strong Libraries, Strong Scores, was held at the Austin Hilton, Austin, Texas during the Texas Library Association's Annual Conference and was…

  13. EVIDENCE FOR QUASI-ADIABATIC MOTION OF CHARGED PARTICLES IN STRONG CURRENT SHEETS IN THE SOLAR WIND

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Malova, H. V.; Popov, V. Yu.; Grigorenko, E. E.

    We investigate quasi-adiabatic dynamics of charged particles in strong current sheets (SCSs) in the solar wind, including the heliospheric current sheet (HCS), both theoretically and observationally. A self-consistent hybrid model of an SCS is developed in which ion dynamics is described at the quasi-adiabatic approximation, while the electrons are assumed to be magnetized, and their motion is described in the guiding center approximation. The model shows that the SCS profile is determined by the relative contribution of two currents: (i) the current supported by demagnetized protons that move along open quasi-adiabatic orbits, and (ii) the electron drift current. The simplestmore » modeled SCS is found to be a multi-layered structure that consists of a thin current sheet embedded into a much thicker analog of a plasma sheet. This result is in good agreement with observations of SCSs at ∼1 au. The analysis of fine structure of different SCSs, including the HCS, shows that an SCS represents a narrow current layer (with a thickness of ∼10{sup 4} km) embedded into a wider region of about 10{sup 5} km, independently of the SCS origin. Therefore, multi-scale structuring is very likely an intrinsic feature of SCSs in the solar wind.« less

  14. Magnetopause Erosion During the 17 March 2015 Magnetic Storm: Combined Field-Aligned Currents, Auroral Oval, and Magnetopause Observations

    NASA Technical Reports Server (NTRS)

    Le, G.; Luehr, H.; Anderson, B. J.; Strangeway, R. J.; Russell, C. T.; Singer, H.; Slavin, J. A.; Zhang, Y.; Huang, T.; Bromund, K.; hide

    2016-01-01

    We present multimission observations of field-aligned currents, auroral oval, and magnetopause crossings during the 17 March 2015 magnetic storm. Dayside reconnection is expected to transport magnetic flux, strengthen field-aligned currents, lead to polar cap expansion and magnetopause erosion. Our multimission observations assemble evidence for all these manifestations. After a prolonged period of strongly southward interplanetary magnetic field, Swarm and AMPERE observe significant intensification of field-aligned currents .The dayside auroral oval, as seen by DMSP, appears as a thin arc associated with ongoing dayside reconnection. Both the field-aligned currents and the auroral arc move equatorward reaching as low as approx. 60 deg. magnetic latitude. Strong magnetopause erosion is evident in the in situ measurements of the magnetopause crossings by GOES 13/15 and MMS. The coordinated Swarm, AMPERE, DMSP, MMS and GOES observations, with both global and in situ coverage of the key regions, provide a clear demonstration of the effects of dayside reconnection on the entire magnetosphere.

  15. Evidence for a strong sulfur-aromatic interaction derived from crystallographic data.

    PubMed

    Zauhar, R J; Colbert, C L; Morgan, R S; Welsh, W J

    2000-03-01

    We have uncovered new evidence for a significant interaction between divalent sulfur atoms and aromatic rings. Our study involves a statistical analysis of interatomic distances and other geometric descriptors derived from entries in the Cambridge Crystallographic Database (F. H. Allen and O. Kennard, Chem. Design Auto. News, 1993, Vol. 8, pp. 1 and 31-37). A set of descriptors was defined sufficient in number and type so as to elucidate completely the preferred geometry of interaction between six-membered aromatic carbon rings and divalent sulfurs for all crystal structures of nonmetal-bearing organic compounds present in the database. In order to test statistical significance, analogous probability distributions for the interaction of the moiety X-CH(2)-X with aromatic rings were computed, and taken a priori to correspond to the null hypothesis of no significant interaction. Tests of significance were carried our pairwise between probability distributions of sulfur-aromatic interaction descriptors and their CH(2)-aromatic analogues using the Smirnov-Kolmogorov nonparametric test (W. W. Daniel, Applied Nonparametric Statistics, Houghton-Mifflin: Boston, New York, 1978, pp. 276-286), and in all cases significance at the 99% confidence level or better was observed. Local maxima of the probability distributions were used to define a preferred geometry of interaction between the divalent sulfur moiety and the aromatic ring. Molecular mechanics studies were performed in an effort to better understand the physical basis of the interaction. This study confirms observations based on statistics of interaction of amino acids in protein crystal structures (R. S. Morgan, C. E. Tatsch, R. H. Gushard, J. M. McAdon, and P. K. Warme, International Journal of Peptide Protein Research, 1978, Vol. 11, pp. 209-217; R. S. Morgan and J. M. McAdon, International Journal of Peptide Protein Research, 1980, Vol. 15, pp. 177-180; K. S. C. Reid, P. F. Lindley, and J. M. Thornton, FEBS

  16. Weak Evidence of Regeneration Habitat but Strong Evidence of Regeneration Niche for a Leguminous Shrub

    PubMed Central

    Delerue, Florian; Gonzalez, Maya; Michalet, Richard; Pellerin, Sylvain; Augusto, Laurent

    2015-01-01

    The identification of an ecological niche specific to the regeneration phase has mobilised significant attention. However, the importance of the regeneration niche concept remains unclear. Our main objective was to study the existence of such a regeneration niche for a leguminous shrub, Ulex europaeus. This study was carried out in southwest France in the context of water and nutrient stresses (mainly phosphorus limitation) due to the presence of nutrient-poor sandy soils. We analysed the regeneration of the species from the germination of seeds and emergence of new seedlings until the seedlings reached young shrub size. Our design included a P fertilisation treatment. We also investigated microsite characteristics (micro-topography and vegetation development) as they can interact with meteorological conditions and determine water availability for seeds and seedlings. We found that P availability controlled seedling growth and the time necessary to reach young shrub size. Water availability appeared to impact the species germination and seedlings survival. We also found that P and water availability depended on the interactions between microsite characteristics and climatic variations. Finally we found evidence that P and water availability are important ecological factors shaping the regeneration niche of the species, but we found weak evidence that any microsite would be appropriate for the regeneration of the species in the long term. Future studies regarding regeneration niches need to distinguish more clearly the ecological factors important for regeneration (the regeneration niche per se) and the physical world where the seedlings appear and develop (the regeneration habitat). PMID:26098877

  17. Condensation to a strongly correlated dark fluid of two dimensional dipolar excitons

    NASA Astrophysics Data System (ADS)

    Mazuz-Harpaz, Yotam; Cohen, Kobi; Rapaport, Ronen

    2017-08-01

    Recently we reported on the condensation of cold, electrostatically trapped dipolar excitons in GaAs bilayer heterostructure into a new, dense and dark collective phase. Here we analyze and discuss in detail the experimental findings and the emerging evident properties of this collective liquid-like phase. We show that the phase transition is characterized by a sharp increase of the number of non-emitting dipoles, by a clear contraction of the fluid spatial extent into the bottom of the parabolic-like trap, and by spectral narrowing. We extract the total density of the condensed phase which we find to be consistent with the expected density regime of a quantum liquid. We show that there are clear critical temperature and excitation power onsets for the phase transition and that as the power further increases above the critical power, the strong darkening is reduced down until no clear darkening is observed. At this point another transition appears which we interpret as a transition to a strongly repulsive yet correlated e-h plasma. Based on the experimental findings, we suggest that the physical mechanism that may be responsible for the transition is a dynamical final-state stimulation of the dipolar excitons to their dark spin states, which have a long lifetime and thus support the observed sharp increase in density. Further experiments and modeling will hopefully be able to unambiguously identify the physical mechanism behind these recent observations.

  18. Observations and Modeling of Turbulent Air-Sea Coupling in Coastal and Strongly Forced Condition

    NASA Astrophysics Data System (ADS)

    Ortiz-Suslow, David G.

    The turbulent fluxes of momentum, mass, and energy across the ocean-atmosphere boundary are fundamental to our understanding of a myriad of geophysical processes, such as wind-wave generation, oceanic circulation, and air-sea gas transfer. In order to better understand these fluxes, empirical relationships were developed to quantify the interfacial exchange rates in terms of easily observed parameters (e.g., wind speed). However, mounting evidence suggests that these empirical formulae are only valid over the relatively narrow parametric space, i.e. open ocean conditions in light to moderate winds. Several near-surface processes have been observed to cause significant variance in the air-sea fluxes not predicted by the conventional functions, such as a heterogeneous surfaces, swell waves, and wave breaking. Further study is needed to fully characterize how these types of processes can modulate the interfacial exchange; in order to achieve this, a broad investigation into air-sea coupling was undertaken. The primary focus of this work was to use a combination of field and laboratory observations and numerical modeling, in regimes where conventional theories would be expected to breakdown, namely: the nearshore and in very high winds. These seemingly disparate environments represent the marine atmospheric boundary layer at its physical limit. In the nearshore, the convergence of land, air, and sea in a depth-limited domain marks the transition from a marine to a terrestrial boundary layer. Under extreme winds, the physical nature of the boundary layer remains unknown as an intermediate substrate layer, sea spray, develops between the atmosphere and ocean surface. At these ends of the MABL physical spectrum, direct measurements of the near-surface processes were made and directly related to local sources of variance. Our results suggest that the conventional treatment of air-sea fluxes in terms of empirical relationships developed from a relatively narrow set of

  19. Adherence to a Mediterranean-style diet and incident fractures: pooled analysis of observational evidence.

    PubMed

    Kunutsor, Setor K; Laukkanen, Jari A; Whitehouse, Michael R; Blom, Ashley W

    2018-06-01

    The Mediterranean diet is associated with decreased morbidity and mortality from various chronic diseases. Adherence to a Mediterranean-style diet has been suggested to have protective effects on bone health and decreases the incidence of bone fractures, but the evidence is not clear. We conducted a systematic review and meta-analysis of available observational studies to quantify the association between adherence to a Mediterranean-style diet, as assessed by the Mediterranean Diet Score (MDS), and the risk of fractures in the general population. Relevant studies were identified in a literature search of MEDLINE, EMBASE, Web of Science, and reference lists of relevant studies to October 2016. Relative risks (RRS) with 95% confidence intervals (CIs) were aggregated using random-effects models. Five observational studies with data on 353,076 non-overlapping participants and 33,576 total fractures (including 6,881 hip fractures) were included. The pooled fully adjusted RR (95% CI) for hip fractures per 2-point increment in adherence to the MDS was 0.82 (0.71-0.96). Adherence to the MDS was not associated with the risk of any or total fractures based on pooled analysis of only two studies. Limited observational evidence supports a beneficial effect of adherence to a Mediterranean-style diet on the incidence of hip fractures. Well-designed intervention studies are needed to elucidate the relationship between adherence to a Mediterranean-style diet and the risk of adverse bone health outcomes such as fractures.

  20. Optical evidence of strong coupling between valence-band holes and d -localized spins in Zn1-xMnxO

    NASA Astrophysics Data System (ADS)

    Sokolov, V. I.; Druzhinin, A. V.; Gruzdev, N. B.; Dejneka, A.; Churpita, O.; Hubicka, Z.; Jastrabik, L.; Trepakov, V.

    2010-04-01

    We report on optical-absorption study of Zn1-xMnxO (x=0-0.06) films on fused silica substrates taking special attention to the spectral range of the fundamental absorption edge (3.1-4 eV). Well-pronounced excitonic lines observed in the region 3.40-3.45 eV were found to shift to higher energies with increasing Mn concentration. The optical band-gap energy increases with x too, reliably evidencing strong coupling between oxygen holes and localized spins of manganese ions. In the 3.1-3.3 eV region the optical-absorption curve in the manganese-contained films was found to shift to lower energies with respect to that for undoped ZnO. The additional absorption observed in this range is interpreted as a result of splitting of a localized Zhang-Rice-type state into the band gap.

  1. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    NASA Astrophysics Data System (ADS)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.; Nord, B.; Gaitsch, H.; Gaitsch, S.; Lin, H.; Allam, S.; Collett, T. E.; Furlanetto, C.; Gill, M. S. S.; More, A.; Nightingale, J.; Odden, C.; Pellico, A.; Tucker, D. L.; da Costa, L. N.; Fausti Neto, A.; Kuropatkin, N.; Soares-Santos, M.; Welch, B.; Zhang, Y.; Frieman, J. A.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; Desai, S.; Dietrich, J. P.; Drlica-Wagner, A.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; García-Bellido, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; James, D. J.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Menanteau, F.; Miquel, R.; Nichol, R. C.; Nugent, P.; Ogando, R. L. C.; Plazas, A. A.; Reil, K.; Romer, A. K.; Sako, M.; Sanchez, E.; Santiago, B.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.; DES Collaboration

    2017-09-01

    We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median I-band limiting magnitude for extended objects (10σ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an I-band limiting magnitude for extended objects (10σ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified based on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.

  2. Strongly Coupled Nanotube Electromechanical Resonators.

    PubMed

    Deng, Guang-Wei; Zhu, Dong; Wang, Xin-He; Zou, Chang-Ling; Wang, Jiang-Tao; Li, Hai-Ou; Cao, Gang; Liu, Di; Li, Yan; Xiao, Ming; Guo, Guang-Can; Jiang, Kai-Li; Dai, Xing-Can; Guo, Guo-Ping

    2016-09-14

    Coupling an electromechanical resonator with carbon-nanotube quantum dots is a significant method to control both the electronic charge and the spin quantum states. By exploiting a novel microtransfer technique, we fabricate two separate strongly coupled and electrically tunable mechanical resonators for the first time. The frequency of the two resonators can be individually tuned by the bottom gates, and in each resonator, the electron transport through the quantum dot can be strongly affected by the phonon mode and vice versa. Furthermore, the conductance of either resonator can be nonlocally modulated by the other resonator through phonon-phonon interaction between the two resonators. Strong coupling is observed between the phonon modes of the two resonators, where the coupling strength larger than 200 kHz can be reached. This strongly coupled nanotube electromechanical resonator array provides an experimental platform for future studies of the coherent electron-phonon interaction, the phonon-mediated long-distance electron interaction, and entanglement state generation.

  3. Strong motion instrumentation of an RC building structure

    USGS Publications Warehouse

    Li, H.-J.; Celebi, M.

    2001-01-01

    The strong-motion instrumentation scheme of a reinforced concrete building observed by California Strong-Motion Instrumentation Program (CSMIP) is introduced in this paper. The instrumented building is also described and the recorded responses during 1994 Northridge earthquake are provided.

  4. Energy Spectra of Strongly Stratified and Rotating Turbulence

    NASA Technical Reports Server (NTRS)

    Mahalov, Alex; Nicolaenko, Basil; Zhou, Ye

    1998-01-01

    Turbulence under strong stratification and rotation is usually characterized as quasi-two dimensional turbulence. We develop a "quasi-two dimensional" energy spectrum which changes smoothly between the Kolmogorov -5/3 law (no stratification), the -2 scalings of Zhou for the case of strong rotation, as well as the -2 scalings for the case of strong rotation and stratification. For strongly stratified turbulence, the model may give the -2 scaling predicted by Herring; and the -5/3 scaling indicated by some mesoscale observations.

  5. XMM-Newton observations of the supernova remnant IC 443. II. Evidence of stellar ejecta in the inner regions

    NASA Astrophysics Data System (ADS)

    Troja, E.; Bocchino, F.; Miceli, M.; Reale, F.

    2008-07-01

    Aims: We investigate the spatial distribution of the physical and chemical properties of the hot X-ray emitting plasma of the supernova remnant IC 443, to derive important constraints on its ionization stage, on the progenitor supernova explosion, on the age of the remnant, and its physical association with a close pulsar wind nebula. Methods: We present XMM-Newton images of IC 443, a median photon energy map, silicon and sulfur equivalent width maps, and a spatially resolved spectral analysis of a set of homogeneous regions. Results: The hard X-ray thermal emission (1.4-5.0 keV) of IC 443 displays a centrally-peaked morphology, its brightness peaks being associated with hot (kT > 1 keV) X-ray emitting plasma. A ring-shaped structure, characterized by high values of equivalent widths and median photon energy, encloses the PWN. Its hard X-ray emission is spectrally characterized by a collisional ionization equilibrium model, and strong emission lines of Mg, Si, and S, requiring oversolar metal abundances. Dynamically, the location of the ejecta ring suggests an SNR age of ~4000 yr. The presence of overionized plasma in the inner regions of IC 443, addressed in previous works, is much less evident in our observations.

  6. Observations of the Ultraviolet Spectra of Helium (DB) White Dwarfs and a Study of the Ultraviolet Spectra of White Dwarfs Containing Carbon

    NASA Technical Reports Server (NTRS)

    Wegner, G. A.

    1984-01-01

    Strong ultraviolet carbon lines were detected in the spectrum of the southern DC white dwarf BPM 11668. Observations of a number of hotter DB white dwarfs with IUE show no evidence of carbon features. Two additional DA white dwarfs were observed that have the strong unidentified absorption near 1400 A which now seems to be identified with another lower temperature feature as satellite lines to Lyman alpha radiation.

  7. Observational studies of regions of massive star formation

    NASA Astrophysics Data System (ADS)

    Cooper, Heather Danielle Blythe

    2013-03-01

    Massive stars have a profound influence on their surroundings. However, relatively little is known about their formation. The study of massive star formation is hindered by a lack of observational evidence, primarily due to difficulties observing massive stars at early stages in their development. The Red MSX Source survey (RMS survey) is a valuable tool with which to address these issues. Near-infrared H- and K-band spectra were taken for 247 candidate massive young stellar objects (MYSOs), selected from the RMS survey. 195 (∼80%) of the targets are YSOs, of which 131 are massive YSOs (LBOL>5E3L⊙, M>8 M⊙). This is the largest spectroscopic study of massive YSOs to date. This study covers minimally obscured objects right through to very red, dusty sources. Almost all YSOs show some evidence for emission lines, though there is a wide variety of observed properties, with HI, H2 Fe II, and CO among the most commonly observed lines. Evidence for disks and outflows was frequently seen. Comparisons of Brγ and H2 emission with low mass YSOs suggest that the emission mechanism for these lines is the same for low-, intermediate-, and high-mass YSOs, i.e. high-mass YSOs appear to resemble scaled-up versions of low-mass YSOs. It was found that the YSOs form an evolutionary sequence, based on their spectra, consistent with the existing theoretical models. Type I YSOs have strong H2 emission, no ionized lines, and are redder than the other two subtypes. As such, these are considered to be the youngest sources. The Type III sources are bluest, and therefore considered to be the oldest subtype. They have strong H I lines and fluorescent Fe II 1.6878 μm emission. They may also have weak H2 emission. Type III sources may even be beginning to form a mini-H II region. XSHOOTER data from 10 Herbig Be stars were analysed. The evidence suggests that winds and disks are common among Herbig stars, as they are among their main sequence classical Be star counterparts. Line

  8. Anomalously strong observations of PKiKP/PcP amplitude ratios on a global scale

    NASA Astrophysics Data System (ADS)

    Waszek, Lauren; Deuss, Arwen

    2015-07-01

    The inner core boundary marks the phase transition between the solid inner core and the fluid outer core. As the site of inner core solidification, the boundary provides insight into the processes generating the seismic structures of the inner core. In particular, it may hold the key to understanding the previously observed hemispherical asymmetry in inner core seismic velocity, anisotropy, and attenuation. Here we use a large PKiKP-PcP amplitude ratio and travel time residual data set to investigate velocity and density contrast properties near the inner core boundary. Although hemispherical structure at the boundary has been proposed by previous inner core studies, we find no evidence for hemispheres in the amplitude ratios or travel time residuals. In addition, we find that the amplitude ratios are much larger than can be explained by variations in density contrast at the inner core boundary or core-mantle boundary. This indicates that PKiKP is primarily observed when it is anomalously large, due to focusing along its raypath. Using data in which PKiKP is not detected above the noise level, we calculate an upper estimate for the inner core boundary (ICB) density contrast of 1.2 kg m-3. The travel time residuals display large regional variations, which differ on long and short length scales. These regions may be explained by large-scale velocity variations in the F layer just above the inner core boundary, and/or small-scale topography of varying magnitude on the ICB, which also causes the large amplitudes. Such differences could arise from localized freezing and melting of the inner core.

  9. Breast-feeding and cardiovascular risk factors and outcomes in later life: evidence from epidemiological studies.

    PubMed

    Owen, Christopher G; Whincup, Peter H; Cook, Derek G

    2011-11-01

    This paper considers the body of observational evidence examining the association of being breast-fed to cardiovascular risk factors and outcomes in later life, and whether any potentially advantageous findings are causal. Early cardiovascular consequences/correlates of breast-feeding, compared to being formula fed, include markedly higher levels of total blood cholesterol, lower levels of pre-prandial blood glucose and insulin and lower levels of adiposity. However, a key issue is whether these early differences at a period of rapid development programme/influence cardiovascular risk factors and outcomes in later life. Evidence of long-term effects of early feeding, largely from observational studies, has shown that those breast-fed have lower levels of blood total cholesterol, lower risk of type-2 diabetes and marginally lower levels of adiposity and blood pressure in adult life. There is no strong evidence to suggest effects of early feeding on adult levels of blood glucose, blood insulin and CHD outcomes, although further data are needed. However, the influence of confounding factors, such as maternal body size, maternal smoking and socio-demographic factors, and exclusivity of early feeding on these potentially beneficial associations needs to be considered before inferring any causal effects. Moreover, fewer studies have examined whether duration of exclusive breast-feeding has a graded influence on these risk factors and outcomes; such data would help further in deciding upon causal associations. While strong observational evidence suggests nutritional programming of adult cholesterol levels, associations with other markers of cardiometabolic risk and their consequences in later life need to be confirmed in well-conducted observational and experimental studies.

  10. Ooishi's Observation: Viewed in the Context of Jet Stream Discovery.

    NASA Astrophysics Data System (ADS)

    Lewis, John M.

    2003-03-01

    Although aircraft encounters with strong westerly winds during World War II provided the stimulus for postwar research on the jet stream, Wasaburo Ooishi observed these winds in the 1920s. Ooishi's work is reviewed in the context of earlier work in upperair observation and postwar work on the jet stream. An effort is made to reconstruct Ooishi's path to the directorship of Japan's first upper-air observatory by reliance on historical studies and memoirs from the Central Meteorological Observatory.Archival records from Japan's Aerological Observatory have been used to document Ooishi's upperair observations. The first official report from the observatory (written in 1926 and in the auxiliary language of Esperanto) assumes a central role in the study. In this report, data are stratified by season and used to produce the mean seasonal wind profiles. The profile for winter gives the first known evidence of the persistent strong westerlies over Japan that would later become known as the jet stream.

  11. Model predictions of the results of interferometric observations for stars under conditions of strong gravitational scattering by black holes and wormholes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shatskiy, A. A., E-mail: shatskiy@asc.rssi.ru; Kovalev, Yu. Yu.; Novikov, I. D.

    2015-05-15

    The characteristic and distinctive features of the visibility amplitude of interferometric observations for compact objects like stars in the immediate vicinity of the central black hole in our Galaxy are considered. These features are associated with the specifics of strong gravitational scattering of point sources by black holes, wormholes, or black-white holes. The revealed features will help to determine the most important topological characteristics of the central object in our Galaxy: whether this object possesses the properties of only a black hole or also has characteristics unique to wormholes or black-white holes. These studies can be used to interpret themore » results of optical, infrared, and radio interferometric observations.« less

  12. Is the evidence supporting dental procedures strong? A survey of Cochrane systematic reviews in oral health.

    PubMed

    Faggion, Clovis Mariano

    2012-09-01

    Every day a large number and variety of dental procedures are performed in clinical dental practice. There is, however, no information on the overall quality of evidence supporting these procedures. The objective of this study was to assess whether several common dental procedures are based on sound evidence. All Cochrane systematic reviews (CSR) published in dentistry were surveyed. The authors' conclusions about the quality of evidence supporting a specific clinical treatment were used as the measure of outcome. The evidence was considered adequate if the authors did not clearly state the evidence was weak in the conclusions while also suggesting some evidence of the effectiveness of the therapy. Of 120 CSRs assessed, in only 26 (22.0% of the reviews) was the quality of evidence regarded as adequate for supporting clinical decisions, although some methodological limitations were identified in the full text of these reviews. Moreover, the authors of most reviews reported weak or unavailable evidence. On the basis of CSRs, the overall quality of evidence can be regarded as low or nonexistent for most of the dental procedures assessed. The information reported may guide future research. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Evidence of strong ocean heating during glacial periods

    NASA Astrophysics Data System (ADS)

    Zimov, S. A.; Zimov, N.

    2013-12-01

    Numerous hypotheses have addressed glacial-interglacial climatic dynamics, but none of them explain the sharp 25C temperature increase in Greenland in the last deglaciation (Cuffey et al. 1995; Dahl-Jensen et al. 1998). These robust data were obtained through analyzing the temperature profile in the Greenland ice sheet where cold from the last glaciation is preserved in the depth of the glacial sheet. We suggest that during glaciations the ocean accumulated energy: interior ocean water heated up to ~20-30C and during deglaciation this energy is released. In the analogy with reconstructing the ice sheet temperature profiles, the most reliable proof of ocean interior warming during the last glaciation is the heat flux profiles in the bottom sediments. In the final reports based on temperature measurements conducted during the DSDP (Deep Sea Drilling Project) it is stated that heat flux in the bottom sediments doesn't vary with depth and consequently there were no substantial temperature changes in the ocean interior during the last glacial cycle, and heat flux on the surface of the ocean bottom is the geothermal heat flux (Erickson et al., 1975, Hyndman et al., 1987). However, we have critically investigated data in all initial reports of all deep sea drilling projects and have noticed that all temperature data show that heat flow decreases strongly with depth (a minimum of 40 mW/m2), i.e. most of the heat flux detected on the surface of the ocean floor is not the geothermal heat flux but remaining heat that bottom sediments release. Sharp shifts in heat flow are seen within boreholes at depths crossing gas hydrate bottom. All this means that during the last glacial period interior water temperature was on 25-30C degrees warmer. Conversely, in isolated seas heat flow in the sediments shows little change with depth.

  14. Thermodynamics of strongly coupled repulsive Yukawa particles in ambient neutralizing plasma: Thermodynamic instability and the possibility of observation in fine particle plasmas

    NASA Astrophysics Data System (ADS)

    Totsuji, Hiroo

    2008-07-01

    The thermodynamics is analyzed for a system composed of particles with hard cores, interacting via the repulsive Yukawa potential (Yukawa particulates), and neutralizing ambient (background) plasma. An approximate equation of state is given with proper account of the contribution of ambient plasma and it is shown that there exists a possibility for the total isothermal compressibility of Yukawa particulates and ambient plasma to diverge when the coupling between Yukawa particulates is sufficiently strong. In this case, the system undergoes a transition into separated phases with different densities and we have a critical point for this phase separation. Examples of approximate phase diagrams related to this transition are given. It is emphasized that the critical point can be in the solid phase and we have the possibility to observe a solid-solid phase separation. The applicability of these results to fine particle plasmas is investigated. It is shown that, though the values of the characteristic parameters are semiquantitative due to the effects not described by this model, these phenomena are expected to be observed in fine particle plasmas, when approximately isotropic bulk systems are realized with a very strong coupling between fine particles.

  15. Direct Observation of Clinical Skills Feedback Scale: Development and Validity Evidence.

    PubMed

    Halman, Samantha; Dudek, Nancy; Wood, Timothy; Pugh, Debra; Touchie, Claire; McAleer, Sean; Humphrey-Murto, Susan

    2016-01-01

    Construct: This article describes the development and validity evidence behind a new rating scale to assess feedback quality in the clinical workplace. Competency-based medical education has mandated a shift to learner-centeredness, authentic observation, and frequent formative assessments with a focus on the delivery of effective feedback. Because feedback has been shown to be of variable quality and effectiveness, an assessment of feedback quality in the workplace is important to ensure we are providing trainees with optimal learning opportunities. The purposes of this project were to develop a rating scale for the quality of verbal feedback in the workplace (the Direct Observation of Clinical Skills Feedback Scale [DOCS-FBS]) and to gather validity evidence for its use. Two panels of experts (local and national) took part in a nominal group technique to identify features of high-quality feedback. Through multiple iterations and review, 9 features were developed into the DOCS-FBS. Four rater types (residents n = 21, medical students n = 8, faculty n = 12, and educators n = 12) used the DOCS-FBS to rate videotaped feedback encounters of variable quality. The psychometric properties of the scale were determined using a generalizability analysis. Participants also completed a survey to gather data on a 5-point Likert scale to inform the ease of use, clarity, knowledge acquisition, and acceptability of the scale. Mean video ratings ranged from 1.38 to 2.96 out of 3 and followed the intended pattern suggesting that the tool allowed raters to distinguish between examples of higher and lower quality feedback. There were no significant differences between rater type (range = 2.36-2.49), suggesting that all groups of raters used the tool in the same way. The generalizability coefficients for the scale ranged from 0.97 to 0.99. Item-total correlations were all above 0.80, suggesting some redundancy in items. Participants found the scale easy to use (M = 4.31/5) and clear

  16. On The Constitutive Properties Of Strongly Magnetized Matter Observed In A Class Of Solar Ejecta

    NASA Astrophysics Data System (ADS)

    Berdichevsky, D. B.

    2013-12-01

    Several studies of the transient events known as magnetic clouds at 1 AU suggest that they possess the ';1/2' anomalous value for its adiabatic, polytropic index, i.e., γ= 1/2, which implies that the temperature of the plasma decreases with increased density[1-3]. Coronal mass ejections commonly observed by missions like The Solar Terrestrial Relations Observatory (STEREO) have been successfully modeled previously by Berdichevsky Stenborg and Vourlidas[4] as magnetic flux-ropes which propagate from the Sun with uniform velocity. Building on this existing analytical three-dimensional magnetohydrodynamic (MHD) model of a magnetic flux-rope, we present an interpretation of the anomalous and somewhat counterintuitive dynamic property mentioned above. Using plasma and magnetic field observations by the Wind spacecraft for the magnetic cloud of June 2, 1998, we argue that this anomalous polytropic index is indeed a consequence of thermodynamic processes in this strongly magnetized matter. We show that the derived models of Berdichevsky et al.[5, 6] easily accommodate a familiar thermodynamic explanation of this property. Such an explanation may shed light also on the evolution of other astrophysical observations such as remnants in nebulae of past super-novae, as well other transient interstellar events. This MHD solution may be a good way to go beyond gas-dynamics in the development of a coherent picture of shock and its driver, as they are becoming a current interpretation. 1Osherovich, V.A., 1997, Proc. 31st, ESLAB Symp. Correlated Phenomena at the Sun, in the Heliosphere and in Geospace. 2Sittler, E.C., and L.F., Burlaga, 1998, J. Geophys. Res., 103, 17447. 3Nieves-Chinchilla T., and A., Figueroa-Viñas, 2008, J. Geophys. Res., 113, DOI: 10.1029/2007JA012703 4Berdichevsky, Stenborg, and Vourlidas, 2011, ApJ, 741, 47. 5Berdichevsky, D.B., R.L., Lepping, C.J., Farrugia, 2003, Phys.Rev. E, 67, DOI: 10.1103/PhysRevE036405. 6Berdichevsky, D.B. , 2012, Sol. Phys., 284

  17. Observation and control of blinking nitrogen-vacancy centres in discrete nanodiamonds.

    PubMed

    Bradac, C; Gaebel, T; Naidoo, N; Sellars, M J; Twamley, J; Brown, L J; Barnard, A S; Plakhotnik, T; Zvyagin, A V; Rabeau, J R

    2010-05-01

    Nitrogen-vacancy colour centres in diamond can undergo strong, spin-sensitive optical transitions under ambient conditions, which makes them attractive for applications in quantum optics, nanoscale magnetometry and biolabelling. Although nitrogen-vacancy centres have been observed in aggregated detonation nanodiamonds and milled nanodiamonds, they have not been observed in very small isolated nanodiamonds. Here, we report the first direct observation of nitrogen-vacancy centres in discrete 5-nm nanodiamonds at room temperature, including evidence for intermittency in the luminescence (blinking) from the nanodiamonds. We also show that it is possible to control this blinking by modifying the surface of the nanodiamonds.

  18. The DES Bright Arcs Survey: Hundreds of Candidate Strongly Lensed Galaxy Systems from the Dark Energy Survey Science Verification and Year 1 Observations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Diehl, H. T.; Buckley-Geer, E. J.; Lindgren, K. A.

    We report the results of searches for strong gravitational lens systems in the Dark Energy Survey (DES) Science Verification and Year 1 observations. The Science Verification data span approximately 250 sq. deg. with a median i -band limiting magnitude for extended objects (10 σ ) of 23.0. The Year 1 data span approximately 2000 sq. deg. and have an i -band limiting magnitude for extended objects (10 σ ) of 22.9. As these data sets are both wide and deep, they are particularly useful for identifying strong gravitational lens candidates. Potential strong gravitational lens candidate systems were initially identified basedmore » on a color and magnitude selection in the DES object catalogs or because the system is at the location of a previously identified galaxy cluster. Cutout images of potential candidates were then visually scanned using an object viewer and numerically ranked according to whether or not we judged them to be likely strong gravitational lens systems. Having scanned nearly 400,000 cutouts, we present 374 candidate strong lens systems, of which 348 are identified for the first time. We provide the R.A. and decl., the magnitudes and photometric properties of the lens and source objects, and the distance (radius) of the source(s) from the lens center for each system.« less

  19. Influence of regional biomass burning on the highly elevated organic carbon concentrations observed at Gosan, South Korea during a strong Asian dust period.

    PubMed

    Nguyen, Duc Luong; Kim, Jin Young; Ghim, Young Sung; Shim, Shang-Gyoo

    2015-03-01

    PM2.5 carbonaceous particles were measured at Gosan, South Korea during 29 March-11 April 2002 which includes a pollution period (30 March-01 April) when the highest concentrations of major anthropogenic species (nss-SO4 (2-), NO3 (-), and NH4 (+)) were observed and a strong Asian dust (AD) period (08-10 April) when the highest concentrations of mainly dust-originated trace elements (Al, Ca, Mg, and Fe) were seen. The concentrations of elemental carbon (EC) measured in the pollution period were higher than those measured in the strong AD period, whereas an inverse variation in the concentrations of organic carbon (OC) was observed. Based on the OC/EC ratios, the possible source that mainly contributed to the highly elevated OC concentrations measured in the strong AD period was biomass burning. The influence of the long-range transport of smoke plumes emitted from regional biomass burning sources was evaluated by using MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data for fire locations and the potential source contribution function analysis. The most potential source regions of biomass burning were the Primorsky and Amur regions in Far Eastern Russia and southeastern and southwestern Siberia, Russia. Further discussion on the source characteristics suggested that the high OC concentrations measured in the strong AD period were significantly affected by the smoldering phase of biomass burning. In addition to biomass burning, secondary OC (SOC) formed during atmospheric long-range transport should be also considered as an important source of OC concentration measured at Gosan. Although this study dealt with the episodic case of the concurrent increase of dust and biomass burning particles, understanding the characteristics of heterogeneous mixing aerosol is essential in assessing the radiative forcing of aerosol.

  20. Evidence for recombination in scorpion mitochondrial DNA (Scorpiones: Buthidae).

    PubMed

    Gantenbein, Benjamin; Fet, Victor; Gantenbein-Ritter, Iris A; Balloux, François

    2005-04-07

    There has been very little undisputed evidence for recombination in animal mitochondrial DNA (mtDNA) provided so far. Previous unpublished results suggestive of mtDNA recombination in the scorpion family Buthidae, together with cytological evidence for a unique mechanism of mitochondrial fusion in that family, prompted us to investigate this group in more details. First, we sequenced the complete mtDNA genome of Mesobuthus gibbosus, and chose two genes opposing each other (16S and coxI). We then sequenced 150 individuals from the natural populations of four species of Buthidae (Old World genera Buthus and Mesobuthus). We observed strong evidence for widespread recombination through highly significant negative correlations between linkage disequilibrium and physical distance in three out of four species. The evidence is further confirmed when using five other tests for recombination and by the presence of a high amount of homoplasy in phylogenetic trees.

  1. Spatially: resolved heterogeneous dynamics in a strong colloidal gel

    NASA Astrophysics Data System (ADS)

    Buzzaccaro, Stefano; Alaimo, Matteo David; Secchi, Eleonora; Piazza, Roberto

    2015-05-01

    We re-examine the classical problem of irreversible colloid aggregation, showing that the application of Digital Fourier Imaging (DFI), a class of optical correlation methods that combine the power of light scattering and imaging, allows one to pick out novel useful evidence concerning the restructuring processes taking place in a strong colloidal gel. In particular, the spatially-resolved displacement fields provided by DFI strongly suggest that the temporally-intermittent local rearrangements taking place in the course of gel ageing are characterized by very long-ranged spatial correlations.

  2. C/NOFS Satellite Electric Field and Plasma Density Observations of Plasma Instabilities Below the Equatorial F-Peak -- Evidence for Approximately 500 km-Scale Spread-F "Precursor" Waves Driven by Zonal Shear Flow and km-Scale, Narrow-Banded Irregularities

    NASA Technical Reports Server (NTRS)

    Pfaff, R.; Freudenreich, H.; Klenzing, J.; Liebrecht, C.; Valladares, C.

    2011-01-01

    As solar activity has increased, the ionosphere F-peak has been elevated on numerous occasions above the C/NOFS satellite perigee of 400km. In particular, during the month of April, 2011, the satellite consistently journeyed below the F-peak whenever the orbit was in the region of the South Atlantic anomaly after sunset. During these passes, data from the electric field and plasma density probes on the satellite have revealed two types of instabilities which had not previously been observed in the C/NOFS data set (to our knowledge): The first is evidence for 400-500km-scale bottomside "undulations" that appear in the density and electric field data. In one case, these large scale waves are associated with a strong shear in the zonal E x B flow, as evidenced by variations in the meridional (outward) electric fields observed above and below the F-peak. These undulations are devoid of smaller scale structures in the early evening, yet appear at later local times along the same orbit associated with fully-developed spread-F with smaller scale structures. This suggests that they may be precursor waves for spread-F, driven by a collisional shear instability, following ideas advanced previously by researchers using data from the Jicamarca radar. A second new result (for C/NOFS) is the appearance of km-scale irregularities that are a common feature in the electric field and plasma density data that also appear when the satellite is below the F -peak at night. The vector electric field instrument on C/NOFS clearly shows that the electric field component of these waves is strongest in the zonal direction. These waves are strongly correlated with simultaneous observations of plasma density oscillations and appear both with, and without, evidence of larger-scale spread-F depletions. These km-scale, quasi-coherent waves strongly resemble the bottomside, sinusoidal irregularities reported in the Atmosphere Explorer satellite data set by Valladares et al. [JGR, 88, 8025, 1983

  3. ALMA Observations of Starless Core Substructure in Ophiuchus

    NASA Astrophysics Data System (ADS)

    Kirk, H.; Dunham, M. M.; Di Francesco, J.; Johnstone, D.; Offner, S. S. R.; Sadavoy, S. I.; Tobin, J. J.; Arce, H. G.; Bourke, T. L.; Mairs, S.; Myers, P. C.; Pineda, J. E.; Schnee, S.; Shirley, Y. L.

    2017-04-01

    Compact substructure is expected to arise in a starless core as mass becomes concentrated in the central region likely to form a protostar. Additionally, multiple peaks may form if fragmentation occurs. We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 2 observations of 60 starless and protostellar cores in the Ophiuchus molecular cloud. We detect eight compact substructures which are > 15\\prime\\prime from the nearest Spitzer young stellar object. Only one of these has strong evidence for being truly starless after considering ancillary data, e.g., from Herschel and X-ray telescopes. An additional extended emission structure has tentative evidence for starlessness. The number of our detections is consistent with estimates from a combination of synthetic observations of numerical simulations and analytical arguments. This result suggests that a similar ALMA study in the Chamaeleon I cloud, which detected no compact substructure in starless cores, may be due to the peculiar evolutionary state of cores in that cloud.

  4. Electron Dynamics in Nanostructures in Strong Laser Fields

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kling, Matthias

    2014-09-11

    The goal of our research was to gain deeper insight into the collective electron dynamics in nanosystems in strong, ultrashort laser fields. The laser field strengths will be strong enough to extract and accelerate electrons from the nanoparticles and to transiently modify the materials electronic properties. We aimed to observe, with sub-cycle resolution reaching the attosecond time domain, how collective electronic excitations in nanoparticles are formed, how the strong field influences the optical and electrical properties of the nanomaterial, and how the excitations in the presence of strong fields decay.

  5. The STRONG STAR Multidisciplinary PTSD Research Consortium

    DTIC Science & Technology

    2009-09-01

    superior A.5 Role of the Serotonin Transporter and Serotonergic Hypotheses related to Alcoholism Vulnerability Due to Low Serotonin. Strong...evidence shows that the biological vulnerability of EOA patients may be related to a serotonergic dysfunction (Johnson, 2000; Johnson and Ait-Daoud...transporter (Johnson et al., 2008). These findings of reduced serotonergic functioning in L-carriers is contrary to previous data indicating that the L

  6. Diphotons, new vacuum angles, and strong CP

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Draper, Patrick; McKeen, David

    The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π 0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ ~. We discuss the physics of θ ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ ~. In particular,more » θ ~ can generate an O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.« less

  7. Diphotons, new vacuum angles, and strong CP

    DOE PAGES

    Draper, Patrick; McKeen, David

    2016-04-20

    The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π 0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ ~. We discuss the physics of θ ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ ~. In particular,more » θ ~ can generate an O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.« less

  8. Strong and Long Makes Short: Strong-Pump Strong-Probe Spectroscopy.

    PubMed

    Gelin, Maxim F; Egorova, Dassia; Domcke, Wolfgang

    2011-01-20

    We propose a new time-domain spectroscopic technique that is based on strong pump and probe pulses. The strong-pump strong-probe (SPSP) technique provides temporal resolution that is not limited by the durations of the pump and probe pulses. By numerically exact simulations of SPSP signals for a multilevel vibronic model, we show that the SPSP signals exhibit electronic and vibrational beatings on time scales which are significantly shorter than the pulse durations. This suggests the possible application of SPSP spectroscopy for the real-time investigation of molecular processes that cannot be temporally resolved by pump-probe spectroscopy with weak pump and probe pulses.

  9. Evidence for a current sheet forming in the wake of a coronal mass ejection from multi-viewpoint coronagraph observations

    NASA Astrophysics Data System (ADS)

    Patsourakos, S.; Vourlidas, A.

    2011-01-01

    sheets. Therefore, our multi-viewpoint observations supply strong evidence that the observed post-CME ray is indeed related to a post-CME current sheet. Movies are only available in electronic form at http://www.aanda.org

  10. The Strong Gravitationally Lensed Herschel Galaxy HLock01: Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas

    NASA Astrophysics Data System (ADS)

    Marques-Chaves, Rui; Pérez-Fournon, Ismael; Gavazzi, Raphael; Martínez-Navajas, Paloma I.; Riechers, Dominik; Rigopoulou, Dimitra; Cabrera-Lavers, Antonio; Clements, David L.; Cooray, Asantha; Farrah, Duncan; Ivison, Rob J.; Jiménez-Ángel, Camilo E.; Nayyeri, Hooshang; Oliver, Seb; Omont, Alain; Scott, Douglas; Shu, Yiping; Wardlow, Julie

    2018-02-01

    The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m UV ≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M * ≃ 5 × 1011 M ⊙), with a highly extinguished stellar component (A V ≃ 4.3 ), the LBG is a young, lower-mass (M * ≃ 1 × 1010 M ⊙), but still luminous (10× {L}UV}* ) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C II λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.

  11. Strong brightness variations signal cloudy-to-clear transition of brown dwarfs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Radigan, Jacqueline; Lafrenière, David; Artigau, Etienne

    2014-10-01

    We report the results of a J-band search for cloud-related variability in the atmospheres of 62 L4-T9 dwarfs using the Du Pont 2.5 m telescope at Las Campanas Observatory and the Canada-France-Hawaii Telescope on Mauna Kea. We find 9 of 57 objects included in our final analysis to be significantly variable with >99% confidence, 5 of which are new discoveries. In our study, strong signals (peak-to-peak amplitudes >2%) are confined to the L/T transition (4/16 objects with L9-T3.5 spectral types and 0/41 objects for all other spectral types). The probability that the observed occurrence rates for strong variability inside andmore » outside the L/T transition originate from the same underlying true occurrence rate is excluded at >99.7% confidence. Based on a careful assessment of our sensitivity to astrophysical signals, we infer that 39{sub −14}{sup +16}% of L9-T3.5 dwarfs are strong variables on rotational timescales. If we consider only L9-T3.5 dwarfs with 0.8 < J – K {sub s} < 1.5, and assume an isotropic distribution of spin axes for our targets, we find that 80{sub −19}{sup +18}% would be strong variables if viewed edge-on; azimuthal symmetry and/or binarity may account for non-variable objects in this group. These observations suggest that the settling of condensate clouds below the photosphere in brown dwarf (BD) atmospheres does not occur in a spatially uniform manner. Rather, the formation and sedimentation of dust grains at the L/T transition is coupled to atmospheric dynamics, resulting in highly contrasting regions of thick and thin clouds and/or clearings. Outside the L/T transition we identify five weak variables (peak-to-peak amplitudes of 0.6%-1.6%). Excluding L9-T3.5 spectral types, we infer that 60{sub −18}{sup +22}% of targets vary with amplitudes of 0.5%-1.6%, suggesting that surface heterogeneities are common among L and T dwarfs. Our survey establishes a significant link between strong variability and L/T transition spectral types

  12. Careers in Forensics: Analysis, Evidence, and Law

    ERIC Educational Resources Information Center

    Torpey, Elka Maria

    2009-01-01

    In legal proceedings, a case is only as strong as its evidence. And whether that evidence is strong depends, in large part, on the work of forensic specialists. The field of forensics is broad and involves many kinds of workers. Some of them are involved in crimesolving. Others, such as forensic social workers or forensic economists, help to…

  13. Evidence-Based Reform in Education

    ERIC Educational Resources Information Center

    Slavin, Robert E.

    2017-01-01

    Education policies should support the use of programs and practices with strong evidence of effectiveness. The Every Student Succeeds Act (ESSA) contains evidence standards and incentives to use programs that meet them. This provides a great opportunity for evidence to play a stronger role in decisions about education programs and practices.…

  14. Experimental observation of Lorenz chaos in the Quincke rotor dynamics.

    PubMed

    Peters, François; Lobry, Laurent; Lemaire, Elisabeth

    2005-03-01

    In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz equations. In particular, we observe two bifurcations in our experimental system. Above a critical value of the electric field, the cylinder rotates at a constant rate. At a second bifurcation, the system becomes chaotic. The characteristic shape of the experimental first return map provides strong evidence for Lorenz-type chaos.

  15. Experimental observation of Lorenz chaos in the Quincke rotor dynamics

    NASA Astrophysics Data System (ADS)

    Peters, François; Lobry, Laurent; Lemaire, Elisabeth

    2005-03-01

    In this paper, we report experimental evidence of Lorenz chaos for the Quincke rotor dynamics. We study the angular motion of an insulating cylinder immersed in slightly conducting oil and submitted to a direct current electric field. The simple equations which describe the dynamics of the rotor are shown to be equivalent to the Lorenz equations. In particular, we observe two bifurcations in our experimental system. Above a critical value of the electric field, the cylinder rotates at a constant rate. At a second bifurcation, the system becomes chaotic. The characteristic shape of the experimental first return map provides strong evidence for Lorenz-type chaos.

  16. A visual processing advantage for young-adolescent deaf observers: Evidence from face and object matching tasks

    PubMed Central

    Megreya, Ahmed M.; Bindemann, Markus

    2017-01-01

    It is unresolved whether the permanent auditory deprivation that deaf people experience leads to the enhanced visual processing of faces. The current study explored this question with a matching task in which observers searched for a target face among a concurrent lineup of ten faces. This was compared with a control task in which the same stimuli were presented upside down, to disrupt typical face processing, and an object matching task. A sample of young-adolescent deaf observers performed with higher accuracy than hearing controls across all of these tasks. These results clarify previous findings and provide evidence for a general visual processing advantage in deaf observers rather than a face-specific effect. PMID:28117407

  17. The Role of Broca's Area in Speech Perception: Evidence from Aphasia Revisited

    ERIC Educational Resources Information Center

    Hickok, Gregory; Costanzo, Maddalena; Capasso, Rita; Miceli, Gabriele

    2011-01-01

    Motor theories of speech perception have been re-vitalized as a consequence of the discovery of mirror neurons. Some authors have even promoted a strong version of the motor theory, arguing that the motor speech system is critical for perception. Part of the evidence that is cited in favor of this claim is the observation from the early 1980s that…

  18. Strong seismic wave scattering beneath Kanto region derived from dense K-NET/KiK-net strong motion network and numerical simulation

    NASA Astrophysics Data System (ADS)

    Takemura, S.; Yoshimoto, K.

    2013-12-01

    Observed seismograms, which consist of the high-frequency body waves through the low-velocity (LV) region at depth of 20-40 km beneath northwestern Chiba in Kanto, show strong peak delay and spindle shape of S waves. By analyzing dense seismic records from K-NET/KiK-net, such spindle-shape S waves are clearly observed in the frequency range of 1-8 Hz. In order to investigate a specific heterogeneous structure to generate such observations, we conduct 3-D finite-difference method (FDM) simulation using realistic heterogeneous models and compare the simulation results with dense strong motion array observations. Our 3-D simulation model is covering the zone 150 km by 64 km in horizontal directions and 75 km in vertical direction, which has been discretized with uniform grid size 0.05 km. We assume a layered background velocity structure, which includes basin structure, crust, mantle and subducting oceanic plate, base on the model proposed by Koketsu et al. (2008). In order to introduce the effect of seismic wave scattering, we assume a stochastic random velocity fluctuation in each layer. Random velocity fluctuations are characterized by exponential-type auto-correlation function (ACF) with correlation distance a = 3 km and rms value of fluctuation e = 0.05 in the upper crust, a = 3 km and e = 0.07 in the lower crust, a = 10 km and e = 0.02 in the mantle. In the subducting oceanic plate, we assume an anisotropic random velocity fluctuation characterized by exponential-type ACF with aH = 10 km in horizontal direction, aZ = 0.5 km in vertical direction and e = 0.02 (e.g., Furumura and Kennett, 2005). In addition, we assume a LV zone at northeastern part of Chiba with depth of 20-40 km (e.g., Matsubara et al., 2004). In the LV zone, random velocity fluctuation characterized by Gaussian-type ACF with a = 1 km and e = 0.07 is superposed on exponential-type ACF with a = 3 km and e = 0.07, in order to modulate the S-wave propagation in the dominant frequency range of

  19. Strong evidence for changing fish reproductive phenology under climate warming on the Tibetan Plateau.

    PubMed

    Tao, Juan; He, Dekui; Kennard, Mark J; Ding, Chengzhi; Bunn, Stuart E; Liu, Chunlong; Jia, Yintao; Che, Rongxiao; Chen, Yifeng

    2018-05-01

    Phenological responses to climate change have been widely observed and have profound and lasting effects on ecosystems and biodiversity. However, compared to terrestrial ecosystems, the long-term effects of climate change on species' phenology are poorly understood in aquatic ecosystems. Understanding the long-term changes in fish reproductive phenology is essential for predicting population dynamics and for informing management strategies, but is currently hampered by the requirement for intensive field observations and larval identification. In this study, a very low-frequency sampling of juveniles and adults combined with otolith measurements (long axis length of the first annulus; LAFA) of an endemic Tibetan Plateau fish (Gymnocypris selincuoensis) was used to examine changes in reproductive phenology associated with climate changes from the 1970s to 2000s. Assigning individual fish to their appropriate calendar year class was assisted by dendrochronological methods (crossdating). The results demonstrated that LAFA was significantly and positively associated with temperature and growing season length. To separate the effects of temperature and the growing season length on LAFA growth, measurements of larval otoliths from different sites were conducted and revealed that daily increment additions were the main contributor (46.3%), while temperature contributed less (12.0%). Using constructed water-air temperature relationships and historical air temperature records, we found that the reproductive phenology of G. selincuoensis was strongly advanced in the spring during the 1970s and 1990s, while the increased growing season length in the 2000s was mainly due to a delayed onset of winter. The reproductive phenology of G. selincuoensis advanced 2.9 days per decade on average from the 1970s to 2000s, and may have effects on recruitment success and population dynamics of this species and other biota in the ecosystem via the food web. The methods used in this study

  20. PICS: SIMULATIONS OF STRONG GRAVITATIONAL LENSING IN GALAXY CLUSTERS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Nan; Gladders, Michael D.; Florian, Michael K.

    2016-09-01

    Gravitational lensing has become one of the most powerful tools available for investigating the “dark side” of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter halos over decades in mass and offers the opportunity to study the distant universe at flux levels and spatial resolutions otherwise unavailable. Studies of strongly lensed variable sources offer even further scientific opportunities. One of the challenges in realizing the potential of strong lensing is to understand the statistical context of both the individual systems that receive extensive follow-up study, as well as that ofmore » the larger samples of strong lenses that are now emerging from survey efforts. Motivated by these challenges, we have developed an image simulation pipeline, Pipeline for Images of Cosmological Strong lensing (PICS), to generate realistic strong gravitational lensing signals from group- and cluster-scale lenses. PICS uses a low-noise and unbiased density estimator based on (resampled) Delaunay Tessellations to calculate the density field; lensed images are produced by ray-tracing images of actual galaxies from deep Hubble Space Telescope observations. Other galaxies, similarly sampled, are added to fill in the light cone. The pipeline further adds cluster member galaxies and foreground stars into the lensed images. The entire image ensemble is then observed using a realistic point-spread function that includes appropriate detector artifacts for bright stars. Noise is further added, including such non-Gaussian elements as noise window-paning from mosaiced observations, residual bad pixels, and cosmic rays. The aim is to produce simulated images that appear identical—to the eye (expert or otherwise)—to real observations in various imaging surveys.« less

  1. PICS: SIMULATIONS OF STRONG GRAVITATIONAL LENSING IN GALAXY CLUSTERS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Nan; Gladders, Michael D.; Rangel, Esteban M.

    2016-08-29

    Gravitational lensing has become one of the most powerful tools available for investigating the “dark side” of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter halos over decades in mass and offers the opportunity to study the distant universe at flux levels and spatial resolutions otherwise unavailable. Studies of strongly lensed variable sources offer even further scientific opportunities. One of the challenges in realizing the potential of strong lensing is to understand the statistical context of both the individual systems that receive extensive follow-up study, as well as that ofmore » the larger samples of strong lenses that are now emerging from survey efforts. Motivated by these challenges, we have developed an image simulation pipeline, Pipeline for Images of Cosmological Strong lensing (PICS), to generate realistic strong gravitational lensing signals from group- and cluster-scale lenses. PICS uses a low-noise and unbiased density estimator based on (resampled) Delaunay Tessellations to calculate the density field; lensed images are produced by ray-tracing images of actual galaxies from deep Hubble Space Telescope observations. Other galaxies, similarly sampled, are added to fill in the light cone. The pipeline further adds cluster member galaxies and foreground stars into the lensed images. The entire image ensemble is then observed using a realistic point-spread function that includes appropriate detector artifacts for bright stars. Noise is further added, including such non-Gaussian elements as noise window-paning from mosaiced observations, residual bad pixels, and cosmic rays. The aim is to produce simulated images that appear identical—to the eye (expert or otherwise)—to real observations in various imaging surveys.« less

  2. Expanding the Evidence Base: Comparing Randomized Controlled Trials and Observational Studies of Statins.

    PubMed

    Atar, Dan; Ong, Seleen; Lansberg, Peter J

    2015-01-01

    It is widely accepted that randomized controlled trials (RCTs) are the gold standard for demonstrating the efficacy of a given therapy (results under ideal conditions). Observational studies, on the other hand, can complement this by demonstrating effectiveness (results under real-world conditions). To examine the role that observational studies can play in complementing data from RCTs, we reviewed published studies for statins, a class of drugs that have been widely used to reduce the risk of cardiovascular (CV) events by lowering low-density lipoprotein cholesterol levels. RCTs have consistently demonstrated the benefits of statin treatment in terms of CV risk reduction and have demonstrated that more intensive statin therapy has incremental benefits over less intensive treatment. Observational studies of statin use in 'real-world' populations have served to augment the evidence base generated from statin RCTs in preselected populations of patients who are often at high CV risk and have led to similar safety and efficacy findings. They have also raised questions about factors affecting medication adherence, under-treatment, switching between statins, and failure to reach low-density lipoprotein cholesterol target levels, questions for which the answers could lead to improved patient care.

  3. Recent results from the SIMECA code and VLTI observations

    NASA Astrophysics Data System (ADS)

    Meilland, A.; Stee, Ph.

    We present recent results on active hot stars using the first VLTI/MIDI and VLTI/AMBER observations, and the SIMECA code developed by Stee (1994). α Arae was the first classical Be star observed with MIDI (June 2003) and AMBER (February 2005). The size of its circumstellar envelope was measured and thanks to the spectrally-resolved interferometric AMBER observations, we were able, for the first time to evidence the Keplerian rotation of the circumstellar disc. MWC 297 is one of the brightest Herbig Be star, and it was then observed during the first commissioning run of AMBER in May 2004. The data obtained were good enough to allow us to infer the accretion disc extension, as well as to put strong constraints on the stellar wind geometry and kinematics.

  4. How Strong Is the Evidence for Sodium Bicarbonate to Prevent Contrast-Induced Acute Kidney Injury After Coronary Angiography and Percutaneous Coronary Intervention?

    PubMed

    Dong, Yuhao; Zhang, Bin; Liang, Long; Lian, Zhouyang; Liu, Jing; Liang, Changhong; Zhang, Shuixing

    2016-02-01

    Hydration with sodium bicarbonate is one of the strategies to prevent contrast-induced acute kidney injury (CI-AKI). The purpose of this study was to determine how strong is the evidence for sodium bicarbonate to prevent CI-AKI after coronary angiography (CAG) and/or percutaneous coronary intervention (PCI).We conducted PubMed, EMBASE, and CENTRAL databases to search for randomized controlled trials (RCTs) comparing the efficacy of sodium bicarbonate with sodium chloride to prevent CI-AKI after CAG and/or PCI. Relative risk (RR), standardized mean difference (SMD), or weighted mean difference (WMD) with 95% confidence intervals (CIs) was calculated. Heterogeneity, publication bias, and study quality were evaluated, sensitivity analyses, cumulative analyses, and subgroup analyses were performed. The risk of random errors was assessed by trial sequential analysis (TSA).Sixteen RCTs (3537 patients) met the eligibility criteria. Hydration with sodium bicarbonate showed significant beneficial effects in preventing CI-AKI (RR 0.67; 95% CI: 0.47-0.96, P = 0.029), decreasing the change in serum creatinine (SCr) (SMD -0.31 95% CI: -0.55 to -0.07, P = 0.011) and estimated glomerular filtration rate (eGFR) (SMD -0.17 95% CI: -0.30 to -0.04, P = 0.013). But no significant differences were observed in the requirement for dialysis (RR 1.11; 95% CI: 0.60-2.07, P = 0.729), mortality (RR 0.71; 95% CI: 0.41-1.21, P = 0.204) and reducing the length of hospital stay (LHS) (WMD -1.47; 95% CI: -4.14 to 1.20, P = 0.279). The result of TSA on incidence of CI-AKI showed the required information size (RIS = 6614) was not reached and cumulative z curve did not cross TSA boundary. The result of TSA on the requirement for dialysis and mortality demonstrated the required information sizes (RIS = 170,510 and 19,516, respectively) were not reached, and the cumulative z-curve did not cross any boundaries.The evidence that sodium bicarbonate reduces the incidence of

  5. Evidence for ground-ice occurrence on asteroid Vesta using Dawn bistatic radar observations

    NASA Astrophysics Data System (ADS)

    Palmer, E. M.; Heggy, E.; Kofman, W. W.

    2017-12-01

    From 2011 to 2012, the Dawn spacecraft orbited asteroid Vesta, the first of its two targets in the asteroid belt, and conducted the first bistatic radar (BSR) experiment at a small-body, during which Dawn's high-gain communications antenna is used to transmit radar waves that scatter from Vesta's surface toward Earth at high incidence angles just before and after occultation of the spacecraft behind the asteroid. Among the 14 observed mid-latitude forward-scatter reflections, the radar cross section ranges from 84 ± 8 km2 (near Saturnalia Fossae) to 3,588 ± 200 km2 (northwest of Caparronia crater), implying substantial spatial variation in centimeter- to decimeter-scale surface roughness. The compared distributions of surface roughness and subsurface hydrogen concentration [H]—measured using data from Dawn's BSR experiment and Gamma Ray and Neutron Spectrometer (GRaND), respectively—reveal the occurrence of heightened subsurface [H] with smoother terrains that cover tens of square kilometers. Furthermore, unlike on the Moon, we observe no correlation between surface roughness and surface ages on Vesta—whether the latter is derived from lunar or asteroid-flux chronology [Williams et al., 2014]—suggesting that cratering processes alone are insufficient to explain Vesta's surface texture at centimeter-to-decimeter scales. Dawn's BSR observations support the hypothesis of transient melting, runoff and recrystallization of potential ground-ice deposits, which are postulated to flow along fractures after an impact, and provide a mechanism for the smoothing of otherwise rough, fragmented impact ejecta. Potential ground-ice presence within Vesta's subsurface was first proposed by Scully et al. [2014], who identified geomorphological evidence for transient water flow along several of Vesta's crater walls using Dawn Framing Camera images. While airless, differentiated bodies such as Vesta and the Moon are thought to have depleted their initial volatile content

  6. Musician's dystonia is highly task specific: no strong evidence for everyday fine motor deficits in patients.

    PubMed

    Hofmann, Aurélie; Grossbach, Michael; Baur, Volker; Hermsdörfer, Joachim; Altenmüller, Eckart

    2015-03-01

    1) To examine the fine motor skills used everyday by patients suffering from musician's dystonia (MD) in the upper limb in order to verify whether MD is task-specific; and 2) to compare the affected and non-affected hands of MD musicians vs healthy musicians in performance of these tasks in order to clarify whether dystonic symptoms can be found in the non-affected side of MD patients. MD is typically considered to be focal and task specific, but patients often report impairment in everyday life activities. Furthermore, in the course of MD, about 15% of patients complain of dystonic symptoms in other parts of the body. Twenty-seven musicians affected by MD and 27 healthy musicians were studied using 1) the Motor Performance Test Series, 2) a kinematic analysis of handwriting, and 3) an assessment of the grip force regulation while lifting and moving a manipulandum. Patients performed most fine motor tasks without any evidence of a deficit. Exclusively in the handwriting tasks (2), they exhibited fewer frequencies of the written trace and a prolonged overall writing time. MD is highly task specific and does not strongly affect other motor skills. The subtle deficits in handwriting may be explained as a consequence of a general psychological disposition rather than as compensatory mechanisms to avoid the appearance of dystonic symptoms. Furthermore, we did not find signs of multifocal motor deficits in the unaffected hands of MD patients.

  7. Strong contribution of immigration to local population regulation: evidence from a migratory passerine.

    PubMed

    Schaub, Michael; Jakober, Hans; Stauber, Wolfgang

    2013-08-01

    A mechanistic understanding of the dynamics of populations requires knowledge about the variation of the underlying demographic rates and about the reasons for their variability. In geographically open populations, immigration is often necessary to prevent declines, but little is known about whether immigration can contribute to its regulation. We studied the dynamics of a Red-backed Shrike population (Lanius collurio) over 36 years in Germany with a Bayesian integrated population model. We estimated mean and temporal variability of population sizes, productivity, apparent survival, and immigration. We assessed how strongly the demographic rates were correlated with population growth to understand the demographic reasons of population change and how strongly the demographic rates were correlated with population size to identify possible density-dependent mechanisms. The shrike population varied between 35 and 74 breeding pairs but did not show a significant trend in population size over time (growth rate 1.002 +/- 0.001 [mean +/- SD]). Apparent survival of females (juveniles 0.06 +/- 0.01; adults 0.37 +/- 0.03) was lower than that of males (juveniles 0.10 +/- 0.01; adults 0.44 +/- 0.02). Immigration rates were substantial and higher in females (0.56 +/- 0.02) than in males (0.43 +/- 0.02), and average productivity was 2.76 +/- 0.14. Without immigration, the Red-backed Shrike population would have declined strongly. Immigration was the strongest driver for the number of females while local recruitment was the most important driver for the number of males. Immigration of both sexes and productivity, but not local recruitment and survival, were subject to density dependence. Density-dependent productivity was not effectively regulating the local population but may have contributed to regulate shrike populations at larger spatial scales. These findings suggest that immigration is not only an important component to prevent a geographically open population from decline

  8. Evidence for Spin Singlet Pairing with Strong Uniaxial Anisotropy in URu2Si2 Using Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Hattori, T.; Sakai, H.; Tokunaga, Y.; Kambe, S.; Matsuda, T. D.; Haga, Y.

    2018-01-01

    In order to identify the spin contribution to superconducting pairing compatible with the so-called "hidden order", Si 29 nuclear magnetic resonance measurements have been performed using a high-quality single crystal of URu2 Si2 . A clear reduction of the Si 29 Knight shift in the superconducting state has been observed under a magnetic field applied along the crystalline c axis, corresponding to the magnetic easy axis. These results provide direct evidence for the formation of spin-singlet Cooper pairs. Consequently, results indicating a very tiny change of the in-plane Knight shift reported previously demonstrate extreme uniaxial anisotropy for the spin susceptibility in the hidden order state.

  9. Observation of inhibited electron-ion coupling in strongly heated graphite

    PubMed Central

    White, T. G.; Vorberger, J.; Brown, C. R. D.; Crowley, B. J. B.; Davis, P.; Glenzer, S. H.; Harris, J. W. O.; Hochhaus, D. C.; Le Pape, S.; Ma, T.; Murphy, C. D.; Neumayer, P.; Pattison, L. K.; Richardson, S.; Gericke, D. O.; Gregori, G.

    2012-01-01

    Creating non-equilibrium states of matter with highly unequal electron and lattice temperatures (Tele≠Tion) allows unsurpassed insight into the dynamic coupling between electrons and ions through time-resolved energy relaxation measurements. Recent studies on low-temperature laser-heated graphite suggest a complex energy exchange when compared to other materials. To avoid problems related to surface preparation, crystal quality and poor understanding of the energy deposition and transport mechanisms, we apply a different energy deposition mechanism, via laser-accelerated protons, to isochorically and non-radiatively heat macroscopic graphite samples up to temperatures close to the melting threshold. Using time-resolved x ray diffraction, we show clear evidence of a very small electron-ion energy transfer, yielding approximately three times longer relaxation times than previously reported. This is indicative of the existence of an energy transfer bottleneck in non-equilibrium warm dense matter. PMID:23189238

  10. Global isolation by distance despite strong regional phylogeography in a small metazoan

    PubMed Central

    Mills, Scott; Lunt, David H; Gómez, Africa

    2007-01-01

    Background Small vagile eukaryotic organisms, which comprise a large proportion of the Earth's biodiversity, have traditionally been thought to lack the extent of population structuring and geographic speciation observed in larger taxa. Here we investigate the patterns of genetic diversity, amongst populations of the salt lake microscopic metazoan Brachionus plicatilis s. s. (sensu stricto) (Rotifera: Monogononta) on a global scale. We examine the phylogenetic relationships of geographic isolates from four continents using a 603 bp fragment of the mitochondrial COI gene to investigate patterns of phylogeographic subdivision in this species. In addition we investigate the relationship between genetic and geographic distances on a global scale to try and reconcile the paradox between the high vagility of this species and the previously reported patterns of restricted gene flow, even over local spatial scales. Results Analysis of global sequence diversity of B. plicatilis s. s. reveals the presence of four allopatric genetic lineages: North American-Far East Asian, Western Mediterranean, Australian, and an Eastern Mediterranean lineage represented by a single isolate. Geographically orientated substructure is also apparent within the three best sampled lineages. Surprisingly, given this strong phylogeographic structure, B. plicatilis s. s. shows a significant correlation between geographic and genetic distance on a global scale ('isolation by distance' – IBD). Conclusion Despite its cosmopolitan distribution and potential for high gene flow, B. plicatilis s. s. is strongly structured at a global scale. IBD patterns have traditionally been interpreted to indicate migration-drift equilibrium, although in this system equilibrium conditions are incompatible with the observed genetic structure. Instead, we suggest the pattern may have arisen through persistent founder effects, acting in a similar fashion to geographic barriers for larger organisms. Our data indicates

  11. Observer Use of Standardized Observation Protocols in Consequential Observation Systems

    ERIC Educational Resources Information Center

    Bell, Courtney A.; Yi, Qi; Jones, Nathan D.; Lewis, Jennifer M.; McLeod, Monica; Liu, Shuangshuang

    2014-01-01

    Evidence from a handful of large-scale studies suggests that although observers can be trained to score reliably using observation protocols, there are concerns related to initial training and calibration activities designed to keep observers scoring accurately over time (e.g., Bell, et al, 2012; BMGF, 2012). Studies offer little insight into how…

  12. VLBA Observations of Strong Anisotripic Radio Scattering Toward the Orion Nebula

    NASA Astrophysics Data System (ADS)

    Kounkel, Marina; Hartmann, Lee; Loinard, Laurent; Mioduszewski, Amy J.; Rodríguez, Luis F.; Ortiz-León, Gisela N.; Johnson, Michael D.; Torres, Rosa M.; Briceño, Cesar

    2018-05-01

    We present observations of VLBA 20, a radio source found toward the edge of the Orion Nebula Cluster (ONC). Nonthermal emission dominates the spectral energy distribution of this object from the radio to mid-infrared regime, suggesting that VLBA 20 is extragalactic. This source is heavily scattered in the radio regime. Very Long Baseline Array observations resolve it to ∼34 × 19 mas at 5 GHz, and the wavelength dependence of the scattering disk is consistent with ν ‑2 at other frequencies. The origin of the scattering is most likely the ionized X-ray emitting gas from the winds of the most massive stars of the ONC. The scattering is highly anisotropic, with the axis ratio of 2:1, higher than what is typically observed toward other sources.

  13. Coherent Vortices in Strongly Coupled Liquids

    NASA Astrophysics Data System (ADS)

    Ashwin, J.; Ganesh, R.

    2011-04-01

    Strongly coupled liquids are ubiquitous in both nature and laboratory plasma experiments. They are unique in the sense that their average potential energy per particle dominates over the average kinetic energy. Using “first principles” molecular dynamics (MD) simulations, we report for the first time the emergence of isolated coherent tripolar vortices from the evolution of axisymmetric flows in a prototype two-dimensional (2D) strongly coupled liquid, namely, the Yukawa liquid. Linear growth rates directly obtained from MD simulations are compared with a generalized hydrodynamic model. Our MD simulations reveal that the tripolar vortices persist over several turn over times and hence may be observed in strongly coupled liquids such as complex plasma, liquid metals and astrophysical systems such as white dwarfs and giant planetary interiors, thereby making the phenomenon universal.

  14. Observations of a Newly "Captured" Magnetosheath Field Line: Evidence for "Double Reconnection"

    NASA Technical Reports Server (NTRS)

    Chandler, Michael O.; Avanov, Levon A.; Craven, Paul D.; Mozer, Forrest S.; Moore, Thomas E.

    2007-01-01

    We have begun an investigation of the nature of the low-latitude boundary layer in the mid-altitude cusp region using data from the Polar spacecraft. This region has been routinely sampled for about three months each year for the periods 1999-2001 and 2004-2006. The low-to-mid-energy ion instruments frequently observed dense, magnetosheath-like plasma deep (in terms of distance from the magnetopause and in invariant latitude) in the magnetosphere. One such case, taken during a period of northward interplanetary magnetic field (IMF), shows magnetosheath ions within the magnetosphere with velocity distributions resulting from two separate merging sites along the same field lines. Cold ionospheric ions were also observed counterstreaming along the field lines, evidence that these field lines were closed. These results are consistent with the hypothesis that double merging can produce closed field .lines populated by solar wind plasma. Through the use of individual cases such as this and statistical studies of a broader database we seek to understand the morphology of the LLBL as it projects from the sub-solar region into the cusp. We will present preliminary results of our ongoing study.

  15. Ammonia-oxidizing archaea have more important role than ammonia-oxidizing bacteria in ammonia oxidation of strongly acidic soils

    PubMed Central

    Zhang, Li-Mei; Hu, Hang-Wei; Shen, Ju-Pei; He, Ji-Zheng

    2012-01-01

    Increasing evidence demonstrated the involvement of ammonia-oxidizing archaea (AOA) in the global nitrogen cycle, but the relative contributions of AOA and ammonia-oxidizing bacteria (AOB) to ammonia oxidation are still in debate. Previous studies suggest that AOA would be more adapted to ammonia-limited oligotrophic conditions, which seems to be favored by protonation of ammonia, turning into ammonium in low-pH environments. Here, we investigated the autotrophic nitrification activity of AOA and AOB in five strongly acidic soils (pH<4.50) during microcosm incubation for 30 days. Significantly positive correlations between nitrate concentration and amoA gene abundance of AOA, but not of AOB, were observed during the active nitrification. 13CO2-DNA-stable isotope probing results showed significant assimilation of 13C-labeled carbon source into the amoA gene of AOA, but not of AOB, in one of the selected soil samples. High levels of thaumarchaeal amoA gene abundance were observed during the active nitrification, coupled with increasing intensity of two denaturing gradient gel electrophoresis bands for specific thaumarchaeal community. Addition of the nitrification inhibitor dicyandiamide (DCD) completely inhibited the nitrification activity and CO2 fixation by AOA, accompanied by decreasing thaumarchaeal amoA gene abundance. Bacterial amoA gene abundance decreased in all microcosms irrespective of DCD addition, and mostly showed no correlation with nitrate concentrations. Phylogenetic analysis of thaumarchaeal amoA gene and 16S rRNA gene revealed active 13CO2-labeled AOA belonged to groups 1.1a-associated and 1.1b. Taken together, these results provided strong evidence that AOA have a more important role than AOB in autotrophic ammonia oxidation in strongly acidic soils. PMID:22134644

  16. Strong electronic interaction and multiple quantum Hall ferromagnetic phases in trilayer graphene

    NASA Astrophysics Data System (ADS)

    Datta, Biswajit; Dey, Santanu; Samanta, Abhisek; Agarwal, Hitesh; Borah, Abhinandan; Watanabe, Kenji; Taniguchi, Takashi; Sensarma, Rajdeep; Deshmukh, Mandar M.

    2017-02-01

    Quantum Hall effect provides a simple way to study the competition between single particle physics and electronic interaction. However, electronic interaction becomes important only in very clean graphene samples and so far the trilayer graphene experiments are understood within non-interacting electron picture. Here, we report evidence of strong electronic interactions and quantum Hall ferromagnetism seen in Bernal-stacked trilayer graphene. Due to high mobility ~500,000 cm2 V-1 s-1 in our device compared to previous studies, we find all symmetry broken states and that Landau-level gaps are enhanced by interactions; an aspect explained by our self-consistent Hartree-Fock calculations. Moreover, we observe hysteresis as a function of filling factor and spikes in the longitudinal resistance which, together, signal the formation of quantum Hall ferromagnetic states at low magnetic field.

  17. Observational signatures of self-destructive civilizations

    NASA Astrophysics Data System (ADS)

    Stevens, Adam; Forgan, Duncan; James, Jack O'malley

    2016-10-01

    We address the possibility that intelligent civilizations that destroy themselves could present signatures observable by humanity. Placing limits on the number of self-destroyed civilizations in the Milky Way has strong implications for the final three terms in Drake's Equation, and would allow us to identify which classes of solution to Fermi's Paradox fit with the evidence (or lack thereof). Using the Earth as an example, we consider a variety of scenarios in which humans could extinguish their own technological civilization. Each scenario presents some form of observable signature that could be probed by astronomical campaigns to detect and characterize extrasolar planetary systems. Some observables are unlikely to be detected at interstellar distances, but some scenarios are likely to produce significant changes in atmospheric composition that could be detected serendipitously with next-generation telescopes. In some cases, the timing of the observation would prove crucial to detection, as the decay of signatures is rapid compared with humanity's communication lifetime. In others, the signatures persist on far longer timescales.

  18. Short- and Long-Term Feedbacks on Vegetation Water Use: Unifying Evidence from Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Mackay, D. S.

    2001-05-01

    Recent efforts to measure and model the interacting influences of climate, soil, and vegetation on soil water and nutrient dynamics have identified numerous important feedbacks that produce nonlinear responses. In particular, plant physiological factors that control rates of transpiration respond to soil water deficits and vapor pressure deficits (VPD) in the short-term, and to climate, nutrient cycling and disturbance in the long-term. The starting point of this presentation is the observation that in many systems, in particular forest ecosystems, conservative water use emerges as a result of short-term closure of stomata in response to high evaporative demand, and long-term vegetative canopy development under nutrient limiting conditions. Evidence for important short-term controls is presented from sap flux measurements of stand transpiration, remote sensing, and modeling of transpiration through a combination of physically-based modeling and Monte Carlo analysis. A common result is a strong association between stomatal conductance (gs) and the negative evaporative gain (∂ gs/∂ VPD) associated with the sensitivity of stomatal closure to rates of water loss. The importance of this association from the standpoint of modeling transpiration depends on the degree of canopy-atmosphere coupling. This suggests possible simplifications to future canopy component models for use in watershed and larger-scale hydrologic models for short-term processes. However, further results are presented from theoretical modeling, which suggest that feedbacks between hydrology and vegetation in current long-term (inter-annual to century) models may be too simple, as they do not capture the spatially variable nature of slow nutrient cycling in response to soil water dynamics and site history. Memory effects in the soil nutrient pools can leave lasting effects on more rapid processes associated with soil, vegetation, atmosphere coupling.

  19. Highly Selective Coupling of Alkenes and Aldehydes Catalyzed by NHC–Ni–P(OPh)3: Synergy Between a Strong σ-Donor and a Strong π-Acceptor**

    PubMed Central

    Ho, Chun-Yu; Jamison, Timothy F.

    2011-01-01

    Both a strong electron donor (IPr) and a strong electron acceptor (P(OPh)3) are necessary for a highly selective, nickel-catalyzed coupling reaction between alkenes, aldehydes, and silyltriflates. Without the phosphite, catalysis is not observed and several side reactions are observed. The phosphite appears to suppress the formation of these byproducts and rescue the catalytic cycle by accelerating reductive elimination from an (IPr–Ni–H)(OTf) complex. PMID:17154217

  20. Observational evidences of viscoelastic behaviour at low strain

    NASA Astrophysics Data System (ADS)

    Daminelli, Rosastella; Marcellini, Alberto; Tento, Alberto

    2014-05-01

    Theoretical formulations of inhomogeneous waves in low-loss media have been suggested by a number of researchers due to the important role played by anelasticity in changing the characteristics of seismic waves. The Homogeneous Isotropic Linear Viscoelastic Model (HILV) introduced by Borcherdt (2009) is particularly promising because of its mathematical simplicity and the handiness to test the model in real seismograms. We showed that the seismograms of the explosion of a 2nd World War bomb found in Milan recorded by a seismic station at 2 km epicentral distance, exhibit a clear elliptical prograde P wave particle motion (Marcellini and Tento, 2011) as predicted by HILV. We observed a similar P wave prograde elliptical motion analysing a ML 4.8 earthquake occurred on July 17, 2011 in the Po Valley at a 48 km epicentral distance from a seismic station located at Palazzo Te, Mantova (Daminelli et al., 2013). In both cases the stations were situated on the deep quaternary sediments of the Po Valley. Based on measured Vp and Vs and the amplitude of the recorded motion, the strain at the station sites was estimated to be 10-6, 10-7. In this paper we extend the analysis of the previously mentioned seismograms to check the feasibility of HILV application to other types of waves that are particularly relevant in fields such as the engineering seismology. We focus on the S waves (as it is well known HILV predicts the split of S in S type I and S type II) of the seismograms of the earthquake recorded in Mantova and on the Rayleigh waves of the explosion recorded in Milan. The results show that observational evidences of HILV are not as clear as for P waves, probably because of noise or superposition of converted waves. However, once established the validity of HILV by P waves (that is very simple), the whole seismograms can be interpreted following HILV, confirming the relevancy of anelasticity also at low strain. Borcherdt, R.D. (2009) 'Viscoelastic Waves in Layered Media

  1. Quantum Liquid Crystal Phases in Strongly Correlated Fermionic Systems

    ERIC Educational Resources Information Center

    Sun, Kai

    2009-01-01

    This thesis is devoted to the investigation of the quantum liquid crystal phases in strongly correlated electronic systems. Such phases are characterized by their partially broken spatial symmetries and are observed in various strongly correlated systems as being summarized in Chapter 1. Although quantum liquid crystal phases often involve…

  2. Observational diagnostics of accretion on young stars and brown dwarfs

    NASA Astrophysics Data System (ADS)

    Stelzer, Beate; Argiroffi, Costanza

    I present a summary of recent observational constraints on the accretion properties of young stars and brown dwarfs with focus on the high-energy emission. In their T Tauri phase young stars assemble a few percent of their mass by accretion from a disk. Various observational signatures of disks around pre-main sequence stars and the ensuing accretion process are found in the IR and optical regime: e.g. excess emission above the stellar photosphere, strong and broad emission lines, optical veiling. At high energies evidence for accretion is less obvious, and the X-ray emission from stars has historically been ascribed to magnetically confined coronal plasmas. While being true for the bulk of the emission, new insight obtained from XMM-Newton and Chandra observations has unveiled contributions from accretion and outflow processes to the X-ray emission from young stars. Their smaller siblings, the brown dwarfs, have been shown to undergo a T Tauri phase on the basis of optical/IR observations of disks and measurements of accretion rates. Most re-cently, first evidence was found for X-rays produced by accretion in a young brown dwarf, complementing the suspected analogy between stars and substellar objects.

  3. Evidence for Patchy Sediment Underthrusting and a Strong, Drained Outer Accretionary Wedge in Central Cascadia: Implications for Dynamic Slip Conditions

    NASA Astrophysics Data System (ADS)

    Tobin, H. J.; Webb, S. I.

    2017-12-01

    The central Cascadia subduction zone forearc in the region offshore Washington, where a hot, young incoming plate is covered by a 2-3 km thick sedimentary sequence, features a wide, very narrowly-tapered outer accretionary wedge composed of landward vergent thrust sheets. Longstanding questions for this region include the position and host-rock environment of the plate boundary décollement fault, the thickness of sedimentary strata underthrust beneath the wedge with the downgoing plate, and the effective stress or pore fluid pressure condition in the wedge and along its base. We have analyzed nine multichannel seismic lines of the 2012 COAST multi-channel seismic reflection survey using both time- and depth- migrated seismic sections for structural interpretation. Results show that there is evidence for two parallel décollement levels, with up to 200 - 500 meters thickness of a mostly-underthrust sequence in places, but which is absent entirely in others. This patchy distribution is mapped and related to features of the overlying wedge structure. We also analyzed the seismic interval velocity distribution produced during pre-stack depth migration imaging, and used it to compute estimated porosity, pore fluid pressure, and effective stress via empirical physical properties transforms. We find that the wedge shows evidence for at most only modest, localized excess pore pressure, and instead most of the wedge appears to be at near-hydrostatic, drained condition. Modest overpressure ratios of up to only 0.15 are detected, localized in the footwalls of thrust splays. We find no evidence for overpressure zones in the underthrust sequence below the upper décollement, in contrast to findings from several other wedges worldwide. Taken together, the accretionary wedge structure and apparent low pore pressure condition here is consistent with a mechanically strong wedge overlying a base that is very weak, at least transiently. By analogy with recent work from Sumatra

  4. High-resolution, terrestrial radar velocity observations and model results reveal a strong bed at stable, tidewater Rink Isbræ, West Greenland

    NASA Astrophysics Data System (ADS)

    Bartholomaus, T. C.; Walker, R. T.; Stearns, L. A.; Fahnestock, M. A.; Cassotto, R.; Catania, G. A.; Felikson, D.; Fried, M.; Sutherland, D.; Nash, J. D.; Shroyer, E.

    2015-12-01

    At tidewater Rink Isbræ, on the central west coast of Greenland, satellite observations reveal that glacier velocities and terminus positions have remained stable, while the lowest 25 km have thinned 30 m since 1985. Over this same time period, other tidewater glaciers in central west Greenland have retreated, thinned and accelerated. Here we present field observations and model results to show that the flow of Rink Isbræ is resisted by unusually high basal shear stresses. Terrestrial radar interferometry (TRI) observations over 9 days in summer 2014 demonstrate weak velocity response to 4 km wide, full thickness calving events. Velocities at the terminus change by +/- 10% in response to rising and falling tides within a partial-width, 2.5-km-long floating ice tongue; however these tidal perturbations damp out within 2 km of the grounding line. Inversions for basal shear stress and force balance analyses together show that basal shear stresses in excess of 300 kPa support the majority of the driving stress at thick, steep Rink Isbræ. These observational and modeling results tell a consistent story in which a strong bed may limit the unstable tidewater glacier retreats observed elsewhere. Rink Isbræ has an erosion resistant quartzite bed with low fracture density. We hypothesize that this geology may play a major role in the bed strength.

  5. De Novo Coding Variants Are Strongly Associated with Tourette Disorder

    PubMed Central

    Willsey, A. Jeremy; Fernandez, Thomas V.; Yu, Dongmei; King, Robert A.; Dietrich, Andrea; Xing, Jinchuan; Sanders, Stephan J.; Mandell, Jeffrey D.; Huang, Alden Y.; Richer, Petra; Smith, Louw; Dong, Shan; Samocha, Kaitlin E.; Neale, Benjamin M.; Coppola, Giovanni; Mathews, Carol A.; Tischfield, Jay A.; Scharf, Jeremiah M.; State, Matthew W.; Heiman, Gary A.

    2017-01-01

    SUMMARY Whole-exome sequencing (WES) and de novo variant detection have proven a powerful approach to gene discovery in complex neurodevelopmental disorders. We have completed WES of 325 Tourette disorder trios from the Tourette International Collaborative Genetics cohort and a replication sample of 186 trios from the Tourette Syndrome Association International Consortium on Genetics (511 total). We observe strong and consistent evidence for the contribution of de novo likely gene-disrupting (LGD) variants (rate ratio [RR] 2.32, p = 0.002). Additionally, de novo damaging variants (LGD and probably damaging missense) are overrepresented in probands (RR 1.37, p = 0.003). We identify four likely risk genes with multiple de novo damaging variants in unrelated probands: WWC1 (WW and C2 domain containing 1), CELSR3 (Cadherin EGF LAG seven-pass G-type receptor 3), NIPBL (Nipped-B-like), and FN1 (fibronectin 1). Overall, we estimate that de novo damaging variants in approximately 400 genes contribute risk in 12% of clinical cases. PMID:28472652

  6. Strong regional atmospheric 14C signature of respired CO 2 observed from a tall tower over the midwestern United States

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    LaFranchi, B. W.; McFarlane, K. J.; Miller, J. B.

    Radiocarbon in CO 2 ( 14CO 2) measurements can aid in discriminating between fast (<1 year) and slower (>5–10 years) cycling of C between the atmosphere and the terrestrial biosphere due to the 14C disequilibrium between atmospheric and terrestrial C. However, 14CO 2 in the atmosphere is typically much more strongly impacted by fossil fuel emissions of CO 2, and, thus, observations often provide little additional constraints on respiratory flux estimates at regional scales. Here we describe a data set of 14CO 2 observations from a tall tower in northern Wisconsin (USA) where fossil fuel influence is far enough removedmore » that during the summer months, the biospheric component of the 14CO 2 budget dominates. We find that the terrestrial biosphere is responsible for a significant contribution to 14CO 2 that is 2–3 times higher than predicted by the Carnegie-Ames-Stanford approach terrestrial ecosystem model for observations made in 2010. This likely includes a substantial contribution from the North American boreal ecoregion, but transported biospheric emissions from outside the model domain cannot be ruled out. The 14CO 2 enhancement also appears somewhat decreased in observations made over subsequent years, suggesting that 2010 may be anomalous. Furthermore, with these caveats acknowledged, we discuss the implications of the observation/model comparison in terms of possible systematic biases in the model versus short-term anomalies in the observations. Going forward, this isotopic signal could be exploited as an important indicator to better constrain both the long-term carbon balance of terrestrial ecosystems and the short-term impact of disturbance-based loss of carbon to the atmosphere.« less

  7. Strong regional atmospheric 14C signature of respired CO 2 observed from a tall tower over the midwestern United States

    DOE PAGES

    LaFranchi, B. W.; McFarlane, K. J.; Miller, J. B.; ...

    2016-08-31

    Radiocarbon in CO 2 ( 14CO 2) measurements can aid in discriminating between fast (<1 year) and slower (>5–10 years) cycling of C between the atmosphere and the terrestrial biosphere due to the 14C disequilibrium between atmospheric and terrestrial C. However, 14CO 2 in the atmosphere is typically much more strongly impacted by fossil fuel emissions of CO 2, and, thus, observations often provide little additional constraints on respiratory flux estimates at regional scales. Here we describe a data set of 14CO 2 observations from a tall tower in northern Wisconsin (USA) where fossil fuel influence is far enough removedmore » that during the summer months, the biospheric component of the 14CO 2 budget dominates. We find that the terrestrial biosphere is responsible for a significant contribution to 14CO 2 that is 2–3 times higher than predicted by the Carnegie-Ames-Stanford approach terrestrial ecosystem model for observations made in 2010. This likely includes a substantial contribution from the North American boreal ecoregion, but transported biospheric emissions from outside the model domain cannot be ruled out. The 14CO 2 enhancement also appears somewhat decreased in observations made over subsequent years, suggesting that 2010 may be anomalous. Furthermore, with these caveats acknowledged, we discuss the implications of the observation/model comparison in terms of possible systematic biases in the model versus short-term anomalies in the observations. Going forward, this isotopic signal could be exploited as an important indicator to better constrain both the long-term carbon balance of terrestrial ecosystems and the short-term impact of disturbance-based loss of carbon to the atmosphere.« less

  8. Strong regional atmospheric 14C signature of respired CO2 observed from a tall tower over the midwestern United States

    NASA Astrophysics Data System (ADS)

    LaFranchi, B. W.; McFarlane, K. J.; Miller, J. B.; Lehman, S. J.; Phillips, C. L.; Andrews, A. E.; Tans, P. P.; Chen, H.; Liu, Z.; Turnbull, J. C.; Xu, X.; Guilderson, T. P.

    2016-08-01

    Radiocarbon in CO2 (14CO2) measurements can aid in discriminating between fast (<1 year) and slower (>5-10 years) cycling of C between the atmosphere and the terrestrial biosphere due to the 14C disequilibrium between atmospheric and terrestrial C. However, 14CO2 in the atmosphere is typically much more strongly impacted by fossil fuel emissions of CO2, and, thus, observations often provide little additional constraints on respiratory flux estimates at regional scales. Here we describe a data set of 14CO2 observations from a tall tower in northern Wisconsin (USA) where fossil fuel influence is far enough removed that during the summer months, the biospheric component of the 14CO2 budget dominates. We find that the terrestrial biosphere is responsible for a significant contribution to 14CO2 that is 2-3 times higher than predicted by the Carnegie-Ames-Stanford approach terrestrial ecosystem model for observations made in 2010. This likely includes a substantial contribution from the North American boreal ecoregion, but transported biospheric emissions from outside the model domain cannot be ruled out. The 14CO2 enhancement also appears somewhat decreased in observations made over subsequent years, suggesting that 2010 may be anomalous. With these caveats acknowledged, we discuss the implications of the observation/model comparison in terms of possible systematic biases in the model versus short-term anomalies in the observations. Going forward, this isotopic signal could be exploited as an important indicator to better constrain both the long-term carbon balance of terrestrial ecosystems and the short-term impact of disturbance-based loss of carbon to the atmosphere.

  9. X ray spectra of X Per. [oso-8 observations

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Robinson-Saba, J.; Serlemitsos, P. J.; Swank, J. H.

    1978-01-01

    The cosmic X-ray spectroscopy experiment on OSO-8 observed X Per for twenty days during two observations in Feb. 1976 and Feb. 1977. The spectrum of X Per varies in phase with its 13.9 min period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, X Per's spectra do not exhibit iron line emission or strong absorption features. The data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low density region far from the optically identified Be star.

  10. Strong-lensing analysis of MACS J0717.5+3745 from Hubble Frontier Fields observations: How well can the mass distribution be constrained?

    NASA Astrophysics Data System (ADS)

    Limousin, M.; Richard, J.; Jullo, E.; Jauzac, M.; Ebeling, H.; Bonamigo, M.; Alavi, A.; Clément, B.; Giocoli, C.; Kneib, J.-P.; Verdugo, T.; Natarajan, P.; Siana, B.; Atek, H.; Rexroth, M.

    2016-04-01

    We present a strong-lensing analysis of MACSJ0717.5+3745 (hereafter MACS J0717), based on the full depth of the Hubble Frontier Field (HFF) observations, which brings the number of multiply imaged systems to 61, ten of which have been spectroscopically confirmed. The total number of images comprised in these systems rises to 165, compared to 48 images in 16 systems before the HFF observations. Our analysis uses a parametric mass reconstruction technique, as implemented in the Lenstool software, and the subset of the 132 most secure multiple images to constrain a mass distribution composed of four large-scale mass components (spatially aligned with the four main light concentrations) and a multitude of galaxy-scale perturbers. We find a superposition of cored isothermal mass components to provide a good fit to the observational constraints, resulting in a very shallow mass distribution for the smooth (large-scale) component. Given the implications of such a flat mass profile, we investigate whether a model composed of "peaky" non-cored mass components can also reproduce the observational constraints. We find that such a non-cored mass model reproduces the observational constraints equally well, in the sense that both models give comparable total rms. Although the total (smooth dark matter component plus galaxy-scale perturbers) mass distributions of both models are consistent, as are the integrated two-dimensional mass profiles, we find that the smooth and the galaxy-scale components are very different. We conclude that, even in the HFF era, the generic degeneracy between smooth and galaxy-scale components is not broken, in particular in such a complex galaxy cluster. Consequently, insights into the mass distribution of MACS J0717 remain limited, emphasizing the need for additional probes beyond strong lensing. Our findings also have implications for estimates of the lensing magnification. We show that the amplification difference between the two models is larger

  11. First XMM-Newton Observations of an Isolated Neutron Star: RXJ0720.4-3125

    NASA Technical Reports Server (NTRS)

    Paerels, Frits; Mori, Kaya; Motch, Christian; Haberl, Frank; Zavlin, Vyacheslav E.; Zane, Silvia; Ramsay, Gavin; Cropper, Mark

    2000-01-01

    We present the high resolution spectrum of the isolated neutron star RXJ0720.4-3125, obtained with the Reflection Grating Spectrometer on XMM-Newton, complemented with the broad band spectrum observed with the EPIC PN camera. The spectrum appears smooth, with no evidence for strong photospheric absorption or emission features. We briefly discuss the implications of our failure to detect structure in the spectrum.

  12. Hemispheric Differences in Strong versus Weak Semantic Priming: Evidence from Event-Related Brain Potentials

    ERIC Educational Resources Information Center

    Frishkoff, Gwen A.

    2007-01-01

    Goals: Research with lateralized word presentation has suggested that strong ("close") and weak ("remote") semantic associates are processed differently in the left and right cerebral hemispheres [e.g., Beeman, M. j., & Chiarello, C. (1998). Complementary right- and left-hemisphere language comprehension. "Current Directions in Psychological…

  13. Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

    NASA Astrophysics Data System (ADS)

    Miller, A. A.; Cao, Y.; Piro, A. L.; Blagorodnova, N.; Bue, B. D.; Cenko, S. B.; Dhawan, S.; Ferretti, R.; Fox, O. D.; Fremling, C.; Goobar, A.; Howell, D. A.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Lunnan, R.; Masci, F. J.; McCully, C.; Nugent, P. E.; Sollerman, J.; Taddia, F.; Kulkarni, S. R.

    2018-01-01

    Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is, when the SN could have first been detected by our survey, occurred only 0.15{+/- }0.070.15 days before our first detection. In the ∼24 hr after discovery, iPTF 16abc rose by ∼2 mag, featuring a near-linear rise in flux for ≳ 3 days. Early spectra show strong C II absorption, which disappears after ∼7 days. Unlike the extensively observed Type Ia SN 2011fe, the {(B-V)}0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.

  14. Observation and quantification of the quantum dynamics of a strong-field excited multi-level system.

    PubMed

    Liu, Zuoye; Wang, Quanjun; Ding, Jingjie; Cavaletto, Stefano M; Pfeifer, Thomas; Hu, Bitao

    2017-01-04

    The quantum dynamics of a V-type three-level system, whose two resonances are first excited by a weak probe pulse and subsequently modified by another strong one, is studied. The quantum dynamics of the multi-level system is closely related to the absorption spectrum of the transmitted probe pulse and its modification manifests itself as a modulation of the absorption line shape. Applying the dipole-control model, the modulation induced by the second strong pulse to the system's dynamics is quantified by eight intensity-dependent parameters, describing the self and inter-state contributions. The present study opens the route to control the quantum dynamics of multi-level systems and to quantify the quantum-control process.

  15. Thermal Infrared Anomalies of Several Strong Earthquakes

    PubMed Central

    Wei, Congxin; Guo, Xiao; Qin, Manzhong

    2013-01-01

    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of “time-frequency relative power spectrum.” (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting. PMID:24222728

  16. Thermal infrared anomalies of several strong earthquakes.

    PubMed

    Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying

    2013-01-01

    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.

  17. Finding Strong Bridges and Strong Articulation Points in Linear Time

    NASA Astrophysics Data System (ADS)

    Italiano, Giuseppe F.; Laura, Luigi; Santaroni, Federico

    Given a directed graph G, an edge is a strong bridge if its removal increases the number of strongly connected components of G. Similarly, we say that a vertex is a strong articulation point if its removal increases the number of strongly connected components of G. In this paper, we present linear-time algorithms for computing all the strong bridges and all the strong articulation points of directed graphs, solving an open problem posed in [2].

  18. Cognitive-Processing Bias in Chinese Student Teachers with Strong and Weak Professional Identity.

    PubMed

    Wang, Xin-Qiang; Zhu, Jun-Cheng; Liu, Lu; Chen, Xiang-Yu

    2017-01-01

    Professional identity plays an important role in career development. Although many studies have examined professional identity, differences in cognitive-processing biases between Chinese student teachers with strong and weak professional identity are poorly understood. The current study adopted Tversky's social-cognitive experimental paradigm to explore cognitive-processing biases in Chinese student teachers with strong and weak professional identity. Experiment 1 showed that participants with strong professional identity exhibited stronger positive-coding bias toward positive profession-related life events, relative to that observed in those with weak professional identity. Experiment 2 showed that participants with strong professional identity exhibited greater recognition bias for previously read items, relative to that observed in those with weak professional identity. Overall, the results suggested that participants with strong professional identity exhibited greater positive cognitive-processing bias relative to that observed in those with weak professional identity.

  19. Understanding forensic expert evaluative evidence: A study of the perception of verbal expressions of the strength of evidence.

    PubMed

    Arscott, Eleanor; Morgan, Ruth; Meakin, Georgina; French, James

    2017-05-01

    Verbal expressions of evidential strength are routinely used when presenting forensic expert evaluative evidence. The degree to which these verbal expressions are interpreted uniformly among different individuals requires further empirical study. This study focussed on groups of individuals with different roles within the criminal justice system and individuals with varying degrees of expertise and knowledge. Three groups of individuals were identified: laypeople, legal professionals and those with some forensic or investigative knowledge. The participants in the study (n=230) were provided with a case summary to which a verbal expression of the strength of evidence was randomly assigned. Participants were subsequently invited to indicate their perception of the strength of the evidence on a scale that was provided. Generally, across the study groups, the trend was one of increased perceived strength of evidence as the intended strength of the verbal expression was increased, with some notable exceptions. In general, there was good concordance between the groups in the way the different expressions were perceived. It was found that participants performed poorly when it came to differentiating between expressions at the 'strong' end of the scale ('strong', 'very strong' and 'extremely strong'). The findings resonate with calls for validated and robust communication frameworks for evaluative opinions. Further empirical research in this area is warranted and that such research can represent an important contribution towards improving the communication and presentation of forensic evidence. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

  20. Strong electronic interaction and multiple quantum Hall ferromagnetic phases in trilayer graphene

    NASA Astrophysics Data System (ADS)

    Datta, Biswajit; Dey, Santanu; Samanta, Abhisek; Borah, Abhinandan; Agarwal, Hitesh; Watanabe, Kenji; Taniguchi, Takashi; Sensarma, Rajdeep; Deshmukh, Mandar

    There is an increasing interest in the electronic properties of few layer graphene as it offers a platform to study electronic interactions because the dispersion of bands can be tuned with number and stacking of layers in combination with electric field. Here, we report evidence of strong electronic interactions and quantum Hall ferromagnetism (QHF) seen in a dual gated ABA trilayer graphene sample. Due to high mobility (500,000 cm2V-1s-1) in our device compared to previous studies, we find all symmetry broken states including ν = 0 filling factor at relatively low magnetic field (6T). Activation measurements show that Landau Level (LL) gaps are enhanced by interactions. Moreover, we observe hysteresis as a function of filling factor and spikes in the longitudinal resistance which, together, signal the formation of QHF states at low magnetic field.

  1. Observation of migrating transverse Anderson localizations of light in nonlocal media.

    PubMed

    Leonetti, Marco; Karbasi, Salman; Mafi, Arash; Conti, Claudio

    2014-05-16

    We report the experimental observation of the interaction and attraction of many localized modes in a two-dimensional system realized by a disordered optical fiber supporting transverse Anderson localization. We show that a nonlocal optically nonlinear response of thermal origin alters the localization length by an amount determined by the optical power and also induces an action at a distance between the localized modes and their spatial migration. Evidence of a collective and strongly interacting regime is given.

  2. Direct Observation of Quantum Coherence in Single-Molecule Magnets

    NASA Astrophysics Data System (ADS)

    Schlegel, C.; van Slageren, J.; Manoli, M.; Brechin, E. K.; Dressel, M.

    2008-10-01

    Direct evidence of quantum coherence in a single-molecule magnet in a frozen solution is reported with coherence times as long as T2=630±30ns. We can strongly increase the coherence time by modifying the matrix in which the single-molecule magnets are embedded. The electron spins are coupled to the proton nuclear spins of both the molecule itself and, interestingly, also to those of the solvent. The clear observation of Rabi oscillations indicates that we can manipulate the spin coherently, an essential prerequisite for performing quantum computations.

  3. Spectroscopic observations of cool degenerate star candidates

    NASA Technical Reports Server (NTRS)

    Hintzen, P.

    1986-01-01

    Spectroscopic observations are reported for 23 Luyten Half-Second degenerate star candidates and for 13 Luyten-Palomar common proper-motion pairs containing possible degenerate star components. Twenty-five degenerate stars are identified, 20 of which lack previous spectroscopy. Most of these stars are cool - Luyten color class g or later. One star, LP 77-57, shows broad continuum depressions similar to those in LHS 1126, which Liebert and Dahn attributed to pressure-shifted C2. A second degenerate star, LHS 290, exhibits apparent strong Swan bands which are blueshifted about 75 A. Further observations, including polarimetry and photometry, are required to appraise the spectroscopic peculiarities of these stars. Finally, five cool, sharp-lined DA white dwarfs have been observed to detect lines of metals and to determine line strengths. None of these DAs show signs of Mg b or the G band, and four show no evidence of Ca II K. The attempt to detect Ca MI in the fifth star, G199-71, was inconclusive.

  4. Further Evidence on the Weak and Strong Versions of the Screening Hypothesis in Greece.

    ERIC Educational Resources Information Center

    Lambropoulos, Haris S.

    1992-01-01

    Uses Greek data for 1981 and 1985 to test screening hypothesis by replicating method proposed by Psacharopoulos. Credentialism, or sheepskin effect of education, directly challenges human capital theory, which views education as a productivity augmenting process. Results do not support the strong version of the screening hypothesis and suggest…

  5. Weekend Effect" in Summertime U.S. Rainfall: Evidence for Midweek Intensification of Storms by Pollution

    NASA Technical Reports Server (NTRS)

    Bell, Thomas L.; Rosenfeld, Daniel; Kim, Kyu-Myong; Hahnenberger, Maura

    2006-01-01

    Persistent and strong dependence of rain rate on the day of the week has been found in Tropical Rainfall Measuring Mission (TRMM) satellite estimates of summer afternoon rainfall over the southeast U.S. and the nearby Atlantic from 1998 to 2005. Midweek (Tue-Thu) rain rates and rain area appear to increase over land, and this increase is accompanied by a corresponding diminution of rainfall over nearby waters. Reanalysis data from atmospheric models, suggest that there is a corresponding weekly variation in atmospheric winds consistent with the changes in rainfall. These variations are almost certainly caused by weekly variations in human activity. The most likely cause of the observed changes in rainfall is the well documented weekly variation in atmospheric pollution. Particulate pollution is highest in the middle of the week. Considerable observational and modeling evidence has accumulated concerning the effects of aerosols on precipitation. Most of this evidence relates to the suppression of precipitation by aerosols, but it has been argued that storms in highly unstable moist environments can be invigorated by aerosols, and some modeling studies seem to confirm this. The strong weekly cycle in rainfall observed over the southeast U.S. along with what appears to be dynamical suppression of rainfall over the nearby Atlantic, and the lack of an observable cycle over the southwest U.S., are consistent with this theory.

  6. ACE/SWICS OBSERVATIONS OF HEAVY ION DROPOUTS WITHIN THE SOLAR WIND

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Weberg, Micah J.; Zurbuchen, Thomas H.; Lepri, Susan T., E-mail: mjweberg@umich.edu, E-mail: thomasz@umich.edu, E-mail: slepri@umich.edu

    2012-11-20

    We present the first in situ observations of heavy ion dropouts within the slow solar wind, observed for select elements ranging from helium to iron. For iron, these dropouts manifest themselves as depletions of the Fe/H ratio by factors up to {approx}25. The events often exhibit mass-dependent fractionation and are contained in slow, unsteady wind found within a few days from known stream interfaces. We propose that such dropouts are evidence of gravitational settling within large coronal loops, which later undergo interchange reconnection and become source regions of slow, unsteady wind. Previously, spectroscopic studies by Raymond et al. in 1997more » (and later Feldman et al. in 1999) have yielded strong evidence for gravitational settling within these loops. However, their expected in situ signature plasma with heavy elements fractionated by mass was not observed prior to this study. Using data from the SWICS instrument on board the Advanced Composition Explorer (ACE), we investigate the composition of the solar wind within these dropouts and explore long term trends over most of a solar cycle.« less

  7. Strong monogamy of multiparty quantum entanglement for partially coherently superposed states

    NASA Astrophysics Data System (ADS)

    Kim, Jeong San

    2016-03-01

    We provide evidence for the validity of strong monogamy inequality of multiparty quantum entanglement using the square of convex-roof extended negativity (SCREN). We first consider a large class of multiqudit mixed states that are in a partially coherent superposition of a generalized W -class state and the vacuum, and provide some useful properties about this class of states. We show that monogamy inequality of multiqudit entanglement in terms of SCREN holds for this class of states. We further show that SCREN strong monogamy inequality of multiqudit entanglement also holds for this class of states. Thus SCREN is a good alternative for characterizing the monogamous and strongly monogamous properties of multiqudit entanglement.

  8. Brief report on a systematic review of youth violence prevention through media campaigns: Does the limited yield of strong evidence imply methodological challenges or absence of effect?

    PubMed

    Cassidy, Tali; Bowman, Brett; McGrath, Chloe; Matzopoulos, Richard

    2016-10-01

    We present a brief report on a systematic review which identified, assessed and synthesized the existing evidence of the effectiveness of media campaigns in reducing youth violence. Search strategies made use of terms for youth, violence and a range of terms relating to the intervention. An array of academic databases and websites were searched. Although media campaigns to reduce violence are widespread, only six studies met the inclusion criteria. There is little strong evidence to support a direct link between media campaigns and a reduction in youth violence. Several studies measure proxies for violence such as empathy or opinions related to violence, but the link between these measures and violence perpetration is unclear. Nonetheless, some evidence suggests that a targeted and context-specific campaign, especially when combined with other measures, can reduce violence. However, such campaigns are less cost-effective to replicate over large populations than generalised campaigns. It is unclear whether the paucity of evidence represents a null effect or methodological challenges with evaluating media campaigns. Future studies need to be carefully planned to accommodate for methodological difficulties as well as to identify the specific elements of campaigns that work, especially in lower and middle income countries. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  9. XMM-Newton Observations of the Cluster of Galaxies Sersic 159-03

    NASA Technical Reports Server (NTRS)

    Kaastra, J. S.; Ferrigno, C.; Tamura, T.; Paerels, F. B. S.; Peterson, J. R.; Mittaz, J. P. D.

    2000-01-01

    The cluster of galaxies Sersic 159-03 was observed with the XMM-Newton X-ray observatory as part of the Guaranteed Time program. X-ray spectra taken with the EPIC and RGS instruments show no evidence for the strong cooling flow derived from previous X-ray observations. There is a significant lack of cool gas below 1.5 keV as compared to standard isobaric cooling flow models. While the oxygen is distributed more or less uniformly over the cluster, iron shows a strong concentration in the center of the cluster, slightly offset from the brightness center but within the central cD galaxy. This points to enhanced type Ia supernova activity in the center of the cluster. There is also an elongated iron-rich structure ex- tending to the east of the cluster, showing the inhomogeneity of the iron distribution. Finally, the temperature drops rapidly beyond 4' from the cluster center.

  10. Using Certification to Promote Uptake of Real-World Evidence by Payers.

    PubMed

    Segal, Jodi B; Kallich, Joel D; Oppenheim, Emma R; Garrison, Louis P; Iqbal, Sheikh Usman; Kessler, Marla; Alexander, G Caleb

    2016-03-01

    Most randomized controlled trials are unable to generate information about a product's real-world effectiveness. Therefore, payers use real-world evidence (RWE) generated in observational studies to make decisions regarding formulary inclusion and coverage. While some payers generate their own RWE, most cautiously rely on RWE produced by manufacturers who have a strong financial interest in obtaining coverage for their products. We propose a process by which an independent body would certify observational studies as generating valid and unbiased estimates of the effectiveness of the intervention under consideration. This proposed process includes (a) establishing transparent criteria for assessment, (b) implementing a process for receipt and review of observational study protocols from interested parties, (c) reviewing the submitted protocol and requesting any necessary revisions, (d) reviewing the study results, (e) assigning a certification status to the submitted evidence, and (f) communicating the certification status to all who seek to use this evidence for decision making. Accrediting organizations such as the National Center for Quality Assurance and the Joint Commission have comparable goals of providing assurance about quality to those who look to their accreditation results. Although we recognize potential barriers, including a slowing of evidence generation and costs, we anticipate that processes can be streamlined, such as when familiar methods or familiar datasets are used. The financial backing for such activities remains uncertain, as does identification of organizations that might serve this certification function. We suggest that the rigor and transparency that will be required with such a process, and the unassailable evidence that it will produce, will be valuable to decision makers.

  11. There is not yet strong evidence that exercise regimens other than pelvic floor muscle training can reduce stress urinary incontinence in women: a systematic review.

    PubMed

    Bø, Kari; Herbert, Robert D

    2013-09-01

    What evidence is there for alternative exercises to specific pelvic floor muscle training for treatment of stress urinary incontinence in women? A systematic review was conducted with searches of PubMed and PEDro to January 2013. The quality of randomised trials was evaluated using the PEDro scale. Each type of exercise was classified as being in a Development Phase, Testing Phase, or Refinement and Dissemination Phase. Women with stress or mixed urinary incontinence with predominantly stress urinary incontinence. Exercise regimens other than pelvic floor muscle training. The primary outcome was urinary leakage. Seven randomised controlled trials were found: three on abdominal training, two on the Paula method, and two on Pilates exercise. The methodological quality score ranged between 4 and 8 with a mean of 5.7. There was no convincing evidence for the effect of these exercise regimens so they remain in the Testing Phase. Because no randomised trials were found for posture correction, breathing exercise, yoga, Tai Chi, and general fitness training, these were classified as being in the Development Phase. There is not yet strong evidence that alternative exercise regimens can reduce urinary leakage in women with stress urinary incontinence. Alternative exercise regimens should not yet be recommended for use in clinical practice for women with stress urinary incontinence. Copyright © 2013 Australian Physiotherapy Association. Published by .. All rights reserved.

  12. Cognitive-Processing Bias in Chinese Student Teachers with Strong and Weak Professional Identity

    PubMed Central

    Wang, Xin-qiang; Zhu, Jun-cheng; Liu, Lu; Chen, Xiang-yu

    2017-01-01

    Professional identity plays an important role in career development. Although many studies have examined professional identity, differences in cognitive-processing biases between Chinese student teachers with strong and weak professional identity are poorly understood. The current study adopted Tversky’s social-cognitive experimental paradigm to explore cognitive-processing biases in Chinese student teachers with strong and weak professional identity. Experiment 1 showed that participants with strong professional identity exhibited stronger positive-coding bias toward positive profession-related life events, relative to that observed in those with weak professional identity. Experiment 2 showed that participants with strong professional identity exhibited greater recognition bias for previously read items, relative to that observed in those with weak professional identity. Overall, the results suggested that participants with strong professional identity exhibited greater positive cognitive-processing bias relative to that observed in those with weak professional identity. PMID:28555123

  13. Observations of circumstellar carbon monoxide and evidence for multiple ejections in red giants

    NASA Technical Reports Server (NTRS)

    Bernat, A. P.

    1981-01-01

    Observations of the fundamental 4.6 micron band of CO in nine red giants are presented. A common feature is multiple absorption lines which are identified as products of separate components or shells. Column densities are derived; the relative values should be free of the uncertainties inherent in determining the absolute scale. These column densities are well fitted by single excitation temperatures for each absorption component; these excitation temperatures are identified with the local kinetic temperatures. There is no correlation of CO column density with either gas or dust column density nor of the expansion velocity of the component with its distance from the star. The evidence is reviewed, and it is concluded that mass loss from red giants is most likely episodic in nature.

  14. Balancing the Evidence: How to Reconcile the Results of Observational Studies vs. Randomized Clinical Trials in Dialysis.

    PubMed

    Shen, Jenny I; Lum, Erik L; Chang, Tara I

    2016-09-01

    Because large randomized clinical trials (RCTs) in dialysis have been relatively scarce, evidence-based dialysis care has depended heavily on the results of observational studies. However, when results from RCTs appear to contradict the findings of observational studies, nephrologists are left to wonder which type of study they should believe. In this editorial, we explore the key differences between observational studies and RCTs in the context of such seemingly conflicting studies in dialysis. Confounding is the major limitation of observational studies, whereas low statistical power and problems with external validity are more likely to limit the findings of RCTs. Differences in the specification of the population, exposure, and outcomes can also contribute to different results among RCTs and observational studies. Rigorous methods are required regardless of what type of study is conducted, and readers should not automatically assume that one type of study design is superior to the other. Ultimately, dialysis care requires both well-designed, well-conducted observational studies and RCTs to move the field forward. © 2016 Wiley Periodicals, Inc.

  15. Balancing the Evidence: How to Reconcile the Results of Observational Studies vs. Randomized Clinical Trials in Dialysis

    PubMed Central

    Shen, Jenny I.; Lum, Erik L.; Chang, Tara I.

    2016-01-01

    Because large randomized clinical trials (RCTs) in dialysis have been relatively scarce, evidence-based dialysis care has depended heavily on the results of observational studies. However, when results from RCTs appear to contradict the findings of observational studies, nephrologists are left to wonder which type of study they should believe. In this editorial we explore the key differences between observational studies and RCTs in the context of such seemingly conflicting studies in dialysis. Confounding is the major limitation of observational studies, while low statistical power and problems with external validity are more likely to limit the findings of RCTs. Differences in the specification of the population, exposure, and outcomes can also contribute to different results among RCTs and observational studies. Rigorous methods are required regardless of what type of study is conducted, and readers should not automatically assume that one type of study design is superior to the other. Ultimately, dialysis care requires both well-designed, well-conducted observational studies and RCTs to move the field forward. PMID:27207819

  16. Observation of strong amplification at 8.8 nm in the TCE scheme by a table-top pumping system

    NASA Astrophysics Data System (ADS)

    Kawachi, Tetsuya; Tanaka, Momoko; Sasaki, Akira; Kishimoto, Maki; Nishiuchi, Mamiko; Yasuike, Kazuhito; Hasegawa, Noboru; Kilpio, Alexander V.; Lu, Peixiang; Tai, Renzhong

    2002-11-01

    We observed strong amplification of the transition of 4d 4p, J = 0 1 (the transition from (3d3/2, 4d3/2)0 to (3d3/2, 4p1/2)1) of the Ni-like lanthanum (La) ions at a wavelength of 8.8 nm pumped by a compact CPA Nd:Glass laser light at a wavelength of 1.053 mum with a pumping energy of 18 J. The experimental gain coefficient and the achieved gain-length product was 14.5 cm-1 and 7.7, respectively. In this experiment, the pumping laser pulse consisted of a pre-pulse with a duration of 200 ps and a 7ps-duration main pulse, separated by 250 ps. A hydrodynamics simulation coupled with a collisional-radiative model showed that the present experimental condition generated a pre-formed plasma with small volume and made it possible by the main pulse to heat the high density region effectively.

  17. World Health Organization recommendations are often strong based on low confidence in effect estimates.

    PubMed

    Alexander, Paul E; Bero, Lisa; Montori, Victor M; Brito, Juan Pablo; Stoltzfus, Rebecca; Djulbegovic, Benjamin; Neumann, Ignacio; Rave, Supriya; Guyatt, Gordon

    2014-06-01

    Expert guideline panelists are sometimes reluctant to offer weak/conditional/contingent recommendations. Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance warns against strong recommendations when confidence in effect estimates is low or very low, suggesting that such recommendations may seldom be justified. We aim to characterize the classification of strength of recommendations and confidence in estimates in World Health Organization (WHO) guidelines that used the GRADE approach and graded both strength and confidence (GRADEd). We reviewed all WHO guidelines (January 2007 to December 2012), identified those that were GRADEd, and, in these, examined the classifications of strong and weak and associated confidence in estimates (high, moderate, low, and very low). We identified 116 WHO guidelines in which 43 (37%) were GRADEd and had 456 recommendations, of which 289 (63.4%) were strong and 167 (36.6%) were conditional/weak. Of the 289 strong recommendations, 95 (33.0%) were based on evidence warranting low confidence in estimates and 65 (22.5%) on evidence warranting very low confidence in estimates (55.5% strong recommendations overall based on low or very low confidence in estimates). Strong recommendations based on low or very low confidence estimates are very frequently made in WHO guidelines. Further study to determine the reasons for such high uncertainty recommendations is warranted. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Local cooling and warming effects of forests based on satellite observations.

    PubMed

    Li, Yan; Zhao, Maosheng; Motesharrei, Safa; Mu, Qiaozhen; Kalnay, Eugenia; Li, Shuangcheng

    2015-03-31

    The biophysical effects of forests on climate have been extensively studied with climate models. However, models cannot accurately reproduce local climate effects due to their coarse spatial resolution and uncertainties, and field observations are valuable but often insufficient due to their limited coverage. Here we present new evidence acquired from global satellite data to analyse the biophysical effects of forests on local climate. Results show that tropical forests have a strong cooling effect throughout the year; temperate forests show moderate cooling in summer and moderate warming in winter with net cooling annually; and boreal forests have strong warming in winter and moderate cooling in summer with net warming annually. The spatiotemporal cooling or warming effects are mainly driven by the two competing biophysical effects, evapotranspiration and albedo, which in turn are strongly influenced by rainfall and snow. Implications of our satellite-based study could be useful for informing local forestry policies.

  19. Caviton dynamics in strong Langmuir turbulence

    NASA Astrophysics Data System (ADS)

    Dubois, Don; Rose, Harvey A.; Russell, David

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound samping the turbulent energy is dominantly in nonlinear caviton excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation collapse burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful HF waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that free Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed.

  20. Caviton dynamics in strong Langmuir turbulence

    NASA Astrophysics Data System (ADS)

    DuBois, Don; Rose, Harvey A.; Russell, David

    1990-01-01

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound damping the turbulent energy is dominantly in non-linear "caviton" excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful HF waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that "free" Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed.

  1. X-ray microprobe of orbital alignment in strong-field ionized atoms.

    PubMed

    Young, L; Arms, D A; Dufresne, E M; Dunford, R W; Ederer, D L; Höhr, C; Kanter, E P; Krässig, B; Landahl, E C; Peterson, E R; Rudati, J; Santra, R; Southworth, S H

    2006-08-25

    We have developed a synchrotron-based, time-resolved x-ray microprobe to investigate optical strong-field processes at intermediate intensities (10(14) - 10(15) W/cm2). This quantum-state specific probe has enabled the direct observation of orbital alignment in the residual ion produced by strong-field ionization of krypton atoms via resonant, polarized x-ray absorption. We found strong alignment to persist for a period long compared to the spin-orbit coupling time scale (6.2 fs). The observed degree of alignment can be explained by models that incorporate spin-orbit coupling. The methodology is applicable to a wide range of problems.

  2. A strong X-ray Flare in 1ES 1959+650

    NASA Astrophysics Data System (ADS)

    Kapanadze, Bidzina

    2016-06-01

    The nearby TeV-detected HBL object 1ES 1959+650 (z=0.047) has been observed by Swift today which revealed a strong X-ray flare in the source. Namely, the observation-binned 0.3-10 keV count rate is 16.49+/-0.15 cts/s that is by a factor 2.45 larger compared to weighted mean count rate from all Swift-XRT pointings to this source, and by 90% larger than the rate recorded during the previous observation (performed on June 4). Note that the higher brightness states were observed only three times in the past (in 2015 September - December; see Kapanadze B. et al. 2016, "A recent strong X-ray flaring activity of 1ES 1959+650 with possibly less efficient stochastic acceleration", MNRASL, in press).

  3. Global Warming: Evidence from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R.; Yoo, J.-M.; Dalu, G.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown onboard sequential, sun-synchronous, polar-orbiting NOAA (National Oceanic and Atmospheric Administration) operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study, we have minimized systematic errors in the time series introduced by satellite orbital drift in an objective manner. This is done with the help of the onboard warm-blackbody temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically-weighted global-mean temperature of the atmosphere, with a peak weight near the mid troposphere, warmed at the rate of 0.13 +/- 0.05 K/decade during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite-deduced result.

  4. Global Warming: Evidence from Satellite Observations

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

    2001-01-01

    Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown on-board sequential, sun-synchronous, polar orbiting NOAA operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study we have minimized systematic errors in the time series introduced by the satellite orbital drift in an objective manner. This is done with the help the onboard warm black body temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically weighted global mean temperature of the atmosphere, with a peak weight near the mid-troposphere, warmed at the rate of 0.13 K per decade (with an uncertainty of 0.05 K per decade) during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite deuced result.

  5. Exceptionally strong hydrogels through self-assembly of an indole-capped dipeptide.

    PubMed

    Martin, Adam D; Robinson, Andrew B; Mason, Alexander F; Wojciechowski, Jonathan P; Thordarson, Pall

    2014-12-21

    The synthesis of a new hydrogelator with an indole capping group, 1, is reported. 1 forms exceptionally strong hydrogels in a variety of environments, with values for the storage modulus G' amongst the highest reported for supramolecular hydrogels. These gels exhibit strong bundling characteristics, which gives the high values for G' observed. Cell viability studies show that at low concentrations, 1 is biocompatible, however upon self-assembly at higher concentrations, cytotoxic effects are observed.

  6. Field induced decrystallization of silicon: Evidence of a microwave non-thermal effect

    NASA Astrophysics Data System (ADS)

    Nozariasbmarz, Amin; Dsouza, Kelvin; Vashaee, Daryoosh

    2018-02-01

    It is rather strange and not fully understood that some materials decrystallize when exposed to microwave radiation, and it is still debatable if such a transformation is a thermal or non-thermal effect. We hereby report experimental evidences that weight the latter effect. First, a single crystal silicon wafer exposed to microwaves showed strong decrystallization at high temperature. Second, when some areas of the wafer were masked with metal coating, only the exposed areas underwent decrystallization. Transmission electron microscopy analysis, x-ray diffraction data, and thermal conductivity measurements all indicated strong decrystallization, which occurred in the bulk of the material and was not a surface effect. These observations favor the existence of a non-thermal microwave effect.

  7. Measuring the power spectrum of dark matter substructure using strong gravitational lensing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hezaveh, Yashar; Dalal, Neal; Holder, Gilbert

    2016-11-01

    In recent years, it has become possible to detect individual dark matter subhalos near images of strongly lensed extended background galaxies. Typically, only the most massive subhalos in the strong lensing region may be detected this way. In this work, we show that strong lenses may also be used to constrain the much more numerous population of lower mass subhalos that are too small to be detected individually. In particular, we show that the power spectrum of projected density fluctuations in galaxy halos can be measured using strong gravitational lensing. We develop the mathematical framework of power spectrum estimation, andmore » test our method on mock observations. We use our results to determine the types of observations required to measure the substructure power spectrum with high significance. We predict that deep observations (∼10 hours on a single target) with current facilities can measure this power spectrum at the 3σ level, with no apparent degeneracy with unknown clumpiness in the background source structure or fluctuations from detector noise. Upcoming ALMA measurements of strong lenses are capable of placing strong constraints on the abundance of dark matter subhalos and the underlying particle nature of dark matter.« less

  8. The "Weekend Effect" in Summertime U.S. Rainfall: Evidence for Midweek Intensification of Storms by Pollution

    NASA Astrophysics Data System (ADS)

    Bell, T. L.; Rosenfeld, D.; Kim, K.; Hahnenberger, M.

    2006-05-01

    Persistent and strong dependence of rain rate on the day of the week has been found in Tropical Rainfall Measuring Mission (TRMM) satellite estimates of summer afternoon rainfall over the southeast U.S. and the nearby Atlantic from 1998 to 2005. Midweek (Tue--Thu) rain rates and rain area appear to increase over land, and this increase is accompanied by a corresponding diminution of rainfall over nearby waters. Reanalysis data from atmospheric models suggest that there is a corresponding weekly variation in atmospheric winds consistent with the changes in rainfall. These variations are almost certainly caused by weekly variations in human activity. The most likely cause of the observed changes in rainfall is the well documented weekly variation in atmospheric pollution. Particulate pollution is highest in the middle of the week. Considerable observational and modeling evidence has accumulated concerning the effects of aerosols on precipitation. Most of this evidence relates to the suppression of precipitation by aerosols, but it has been argued that storms in highly unstable moist environments can be invigorated by aerosols, and some modeling studies seem to confirm this. The strong weekly cycle in rainfall observed over the southeast U.S. along with what appears to be dynamical suppression of rainfall over the nearby Atlantic, and the lack of an observable cycle over the southwest U.S., are consistent with this theory.

  9. Localized surface disruptions observed by InSAR during strong earthquakes in Java and Hawai'i

    USGS Publications Warehouse

    Poland, M.

    2010-01-01

    Interferometric Synthetic Aperture Radar data spanning strong earthquakes on the islands of Java and Hawai‘i in 2006 reveal patches of subsidence and incoherence indicative of localized ground failure. Interferograms spanning the 26 May 2006 Java earthquake suggest an area of about 7.5 km2 of subsidence (~2 cm) and incoherence south of the city of Yogyakarta that correlates with significant damage to housing, high modeled peak ground accelerations, and poorly consolidated geologic deposits. The subsidence and incoherence is inferred to be a result of intense shaking and/or damage. At least five subsidence patches on the west side of the Island of Hawai‘i, ranging 0.3–2.2 km2 in area and 3–8 cm in magnitude, occurred as a result of a pair of strong earthquakes on 15 October 2006. Although no felt reports or seismic data are available from the areas in Hawai‘i, the Java example suggests that the subsidence patches indicate areas of amplified earthquake shaking. Surprisingly, all subsidence areas in Hawai‘i were limited to recent, and supposedly stable, lava flows and may reflect geological conditions not detectable at the surface. In addition, two ‘a‘ā lava flows in Hawai‘i were partially incoherent in interferograms spanning the earthquakes, indicating surface disruption as a result of the earthquake shaking. Coearthquake incoherence of rubbly deposits, like ‘a‘ā flows, should be explored as a potential indicator of earthquake intensity and past strong seismic activity.

  10. Strong tidal dissipation in Io and Jupiter from astrometric observations.

    PubMed

    Lainey, Valéry; Arlot, Jean-Eudes; Karatekin, Ozgür; Van Hoolst, Tim

    2009-06-18

    Io is the volcanically most active body in the Solar System and has a large surface heat flux. The geological activity is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Io's tidal heat comes from the orbital energy of the Io-Jupiter system (resulting in orbital acceleration), whereas dissipation of energy in Jupiter causes Io's orbital motion to decelerate. Here we report a determination of the tidal dissipation in Io and Jupiter through its effect on the orbital motions of the Galilean moons. Our results show that the rate of internal energy dissipation in Io (k(2)/Q = 0.015 +/- 0.003, where k(2) is the Love number and Q is the quality factor) is in good agreement with the observed surface heat flow, and suggest that Io is close to thermal equilibrium. Dissipation in Jupiter (k(2)/Q = (1.102 +/- 0.203) x 10(-5)) is close to the upper bound of its average value expected from the long-term evolution of the system, and dissipation in extrasolar planets may be higher than presently assumed. The measured secular accelerations indicate that Io is evolving inwards, towards Jupiter, and that the three innermost Galilean moons (Io, Europa and Ganymede) are evolving out of the exact Laplace resonance.

  11. Atmospheric CO2 observations and models suggest strong carbon uptake by forests in New Zealand

    NASA Astrophysics Data System (ADS)

    Steinkamp, Kay; Mikaloff Fletcher, Sara E.; Brailsford, Gordon; Smale, Dan; Moore, Stuart; Keller, Elizabeth D.; Baisden, W. Troy; Mukai, Hitoshi; Stephens, Britton B.

    2017-01-01

    A regional atmospheric inversion method has been developed to determine the spatial and temporal distribution of CO2 sinks and sources across New Zealand for 2011-2013. This approach infers net air-sea and air-land CO2 fluxes from measurement records, using back-trajectory simulations from the Numerical Atmospheric dispersion Modelling Environment (NAME) Lagrangian dispersion model, driven by meteorology from the New Zealand Limited Area Model (NZLAM) weather prediction model. The inversion uses in situ measurements from two fixed sites, Baring Head on the southern tip of New Zealand's North Island (41.408° S, 174.871° E) and Lauder from the central South Island (45.038° S, 169.684° E), and ship board data from monthly cruises between Japan, New Zealand, and Australia. A range of scenarios is used to assess the sensitivity of the inversion method to underlying assumptions and to ensure robustness of the results. The results indicate a strong seasonal cycle in terrestrial land fluxes from the South Island of New Zealand, especially in western regions covered by indigenous forest, suggesting higher photosynthetic and respiratory activity than is evident in the current a priori land process model. On the annual scale, the terrestrial biosphere in New Zealand is estimated to be a net CO2 sink, removing 98 (±37) Tg CO2 yr-1 from the atmosphere on average during 2011-2013. This sink is much larger than the reported 27 Tg CO2 yr-1 from the national inventory for the same time period. The difference can be partially reconciled when factors related to forest and agricultural management and exports, fossil fuel emission estimates, hydrologic fluxes, and soil carbon change are considered, but some differences are likely to remain. Baseline uncertainty, model transport uncertainty, and limited sensitivity to the northern half of the North Island are the main contributors to flux uncertainty.

  12. Strong coupling of Asian Monsoon and Antarctic climates on sub-orbital timescales

    PubMed Central

    Chen, Shitao; Wang, Yongjin; Cheng, Hai; Edwards, R. Lawrence; Wang, Xianfeng; Kong, Xinggong; Liu, Dianbing

    2016-01-01

    There is increasing evidence that millennial-scale climate variability played an active role on orbital-scale climate changes, but the mechanism for this remains unclear. A 230Th-dated stalagmite δ18O record between 88 and 22 thousand years (ka) ago from Yongxing Cave in central China characterizes changes in Asian monsoon (AM) strength. After removing the 65°N insolation signal from our record, the δ18O residue is strongly anti-phased with Antarctic temperature variability on sub-orbital timescales during the Marine Isotope Stage (MIS) 3. Furthermore, once the ice volume signal from Antarctic ice core records were removed and extrapolated back to the last two glacial-interglacial cycles, we observe a linear relationship for both short- and long-duration events between Asian and Antarctic climate changes. This provides the robust evidence of a link between northern and southern hemisphere climates that operates through changes in atmospheric circulation. We find that the weakest monsoon closely associated with the warmest Antarctic event always occurred during the Terminations. This finding, along with similar shifts in the opal flux record, suggests that millennial-scale events play a key role in driving the deglaciation through positive feedbacks associated with enhanced upwelling and increasing CO2. PMID:27605015

  13. Strong monogamy conjecture for multiqubit entanglement: the four-qubit case.

    PubMed

    Regula, Bartosz; Di Martino, Sara; Lee, Soojoon; Adesso, Gerardo

    2014-09-12

    We investigate the distribution of bipartite and multipartite entanglement in multiqubit states. In particular, we define a set of monogamy inequalities sharpening the conventional Coffman-Kundu-Wootters constraints, and we provide analytical proofs of their validity for relevant classes of states. We present extensive numerical evidence validating the conjectured strong monogamy inequalities for arbitrary pure states of four qubits.

  14. Chandra ACIS Observations of Jovian X-Ray Emission

    NASA Technical Reports Server (NTRS)

    Garmire, Gordon; Elsner, Ronald; Feigelson, Eric; Ford, Peter; Gladstone, G. Randall; Hurley, Kevin; Metzger, Albert; Waite, J. Hunter, Jr.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    On November 25 and 26, 1999, the Chandra X-ray spacecraft conducted a set of four 19,000 sec observations of Jupiter. The ACIS-S instrument configuration was used for its good low energy efficiency and spatial resolution. An anomalous response was obtained which was subsequently attributed to strong jovian infrared radiation penetrating the detector and piling up spurious events across the entire X-ray range. However, the pre-observation establishment of an offsetting bias field has allowed the recovery of data from that portion of Jupiter's disc which remained within the elevated portion of the bias field during the observation. This ranges from fewer than 3000 sec to the entire observing time for about 10% of the planet. Auroral emission is seen near both poles in each observation. The northern aurora ia overall more intense than the southern, consistent with prior Einstein and ROSAT Observatory results. The southern aurora shows more modulation with Jupiter's rotation than the northern. Spatial resolution has been improved by at least a factor of two over prior measurements but convincing evidence of structure has not been seen. Lower latitude emission, first observed by ROSAT, is confirmed with flux levels averaging more than a factor of five below peak auroral values. Pronounced variation in the observed emission has occurred over the observing period. The spectral response extends from 0.24 keV, below which noise dominates, to about 1.2 keV. For all four observations the spectrum is clearly enhanced between 0.45 and 0.85 keV. This is apparently unequivocal evidence that Jupiter's X-ray emission is the result of oxygen and perhaps sulfur ions precipitating into the planet's atmosphere, where they undergo charge exchange interactions. The identification of specific transitions lines in the spectrum is among the ongoing efforts. A bremsstrahlung component has not yet been identified.

  15. Gossip as an alternative for direct observation in games of indirect reciprocity.

    PubMed

    Sommerfeld, Ralf D; Krambeck, Hans-Jürgen; Semmann, Dirk; Milinski, Manfred

    2007-10-30

    Communication about social topics is abundant in human societies, and many functions have been attributed to such gossiping. One of these proposed functions is the management of reputations. Reputation by itself has been shown to have a strong influence on cooperation dynamics in games of indirect reciprocity, and this notion helps to explain the observed high level of cooperation in humans. Here we designed a game to test a widespread assumption that gossip functions as a vector for the transmission of social information. This empirical study (with 14 groups of nine students each) focuses on the composition of gossip, information transfer by gossip, and the behavior based on gossip information. We show that gossip has a strong influence on the resulting behavior even when participants have access to the original information (i.e., direct observation) as well as gossip about the same information. Thus, it is evident that gossip has a strong manipulative potential. Furthermore, gossip about cooperative individuals is more positive than gossip about uncooperative individuals, gossip comments transmit social information successfully, and cooperation levels are higher when people encounter positive compared with negative gossip.

  16. Gossip as an alternative for direct observation in games of indirect reciprocity

    PubMed Central

    Sommerfeld, Ralf D.; Krambeck, Hans-Jürgen; Semmann, Dirk; Milinski, Manfred

    2007-01-01

    Communication about social topics is abundant in human societies, and many functions have been attributed to such gossiping. One of these proposed functions is the management of reputations. Reputation by itself has been shown to have a strong influence on cooperation dynamics in games of indirect reciprocity, and this notion helps to explain the observed high level of cooperation in humans. Here we designed a game to test a widespread assumption that gossip functions as a vector for the transmission of social information. This empirical study (with 14 groups of nine students each) focuses on the composition of gossip, information transfer by gossip, and the behavior based on gossip information. We show that gossip has a strong influence on the resulting behavior even when participants have access to the original information (i.e., direct observation) as well as gossip about the same information. Thus, it is evident that gossip has a strong manipulative potential. Furthermore, gossip about cooperative individuals is more positive than gossip about uncooperative individuals, gossip comments transmit social information successfully, and cooperation levels are higher when people encounter positive compared with negative gossip. PMID:17947384

  17. Constraints on holographic cosmologies from strong lensing systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cárdenas, Víctor H.; Bonilla, Alexander; Motta, Verónica

    We use strongly gravitationally lensed (SGL) systems to put additional constraints on a set of holographic dark energy models. Data available in the literature (redshift and velocity dispersion) is used to obtain the Einstein radius and compare it with model predictions. We found that the ΛCDM is the best fit to the data. Although a preliminary statistical analysis seems to indicate that two of the holographic models studied show interesting agreement with observations, a stringent test lead us to the result that neither of the holographic models are competitive with the ΛCDM. These results highlight the importance of Strong Lensingmore » measurements to provide additional observational constraints to alternative cosmological models, which are necessary to shed some light into the dark universe.« less

  18. In Situ Detection of Strong Langmuir Turbulence Processes in Solar Type III Radio Bursts

    NASA Technical Reports Server (NTRS)

    Golla, Thejappa; Macdowall, Robert J.; Bergamo, M.

    2012-01-01

    The high time resolution observations obtained by the WAVES experiment of the STEREO spacecraft in solar type III radio bursts show that Langmuir waves often occur as intense localized wave packets. These wave packets are characterized by short durations of only a few ms and peak intensities, which well exceed the supersonic modulational instability (MI) thresholds. These timescales and peak intensities satisfy the criterion of the solitons collapsed to spatial scales of a few hundred Debye lengths. The spectra of these wave packets consist of primary spectral peaks corresponding to beam-resonant Langmuir waves, two or more sidebands corresponding to down-shifted and up-shifted daughter Langmuir waves, and low frequency enhancements below a few hundred Hz corresponding to daughter ion sound waves. The frequencies and wave numbers of these spectral components satisfy the resonance conditions of the modulational instability (MI). Moreover, the tricoherences, computed using trispectral analysis techniques show that these spectral components are coupled to each other with a high degree of coherency as expected of the MI type of four wave interactions. The high intensities, short scale lengths, sideband spectral structures and low frequency spectral enhancements and, high levels of tricoherences amongst the spectral components of these wave packets provide unambiguous evidence for the supersonic MI and related strong turbulence processes in type III radio bursts. The implication of these observations include: (1) the MI and related strong turbulence processes often occur in type III source regions, (2) the strong turbulence processes probably play very important roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation at the fundamental and second harmonic of the electron plasma frequency, fpe, and (3) the Langmuir collapse probably follows the route of MI in type III radio bursts.

  19. Observational evidence of aging processes in comets

    NASA Astrophysics Data System (ADS)

    Meech, Karen J.

    1991-10-01

    Emphasis was on searching for systematic differences among two groups of comets: periodic comets which spend most of their time in the vicinity of the inner Solar System and the new comets which are believed to be passing through the inner Solar System for the first time. Such differences are expected, but have never been observed, in part because there has never been a systematic observational program aimed at addressing this question. Understanding possible physical and compositional differences between these two groups will lead to a better understanding of the cometary formation conditions in the early Solar System. The employed method studies the activity in the comets as a function of distance by obtaining charge coupled device (CCD) observations of the comets at frequent intervals on both the pre- and post-perihelion legs of their orbits in order to ascertain the distances at the onset and turn-off of activity through comparison with sublimation models.

  20. Evolutionary games on cycles with strong selection

    NASA Astrophysics Data System (ADS)

    Altrock, P. M.; Traulsen, A.; Nowak, M. A.

    2017-02-01

    Evolutionary games on graphs describe how strategic interactions and population structure determine evolutionary success, quantified by the probability that a single mutant takes over a population. Graph structures, compared to the well-mixed case, can act as amplifiers or suppressors of selection by increasing or decreasing the fixation probability of a beneficial mutant. Properties of the associated mean fixation times can be more intricate, especially when selection is strong. The intuition is that fixation of a beneficial mutant happens fast in a dominance game, that fixation takes very long in a coexistence game, and that strong selection eliminates demographic noise. Here we show that these intuitions can be misleading in structured populations. We analyze mean fixation times on the cycle graph under strong frequency-dependent selection for two different microscopic evolutionary update rules (death-birth and birth-death). We establish exact analytical results for fixation times under strong selection and show that there are coexistence games in which fixation occurs in time polynomial in population size. Depending on the underlying game, we observe inherence of demographic noise even under strong selection if the process is driven by random death before selection for birth of an offspring (death-birth update). In contrast, if selection for an offspring occurs before random removal (birth-death update), then strong selection can remove demographic noise almost entirely.

  1. Redox processes at a nanostructured interface under strong electric fields.

    PubMed

    Steurer, Wolfram; Surnev, Svetlozar; Netzer, Falko P; Sementa, Luca; Negreiros, Fabio R; Barcaro, Giovanni; Durante, Nicola; Fortunelli, Alessandro

    2014-09-21

    Manipulation of chemistry and film growth via external electric fields is a longstanding goal in surface science. Numerous systems have been predicted to show such effects but experimental evidence is sparse. Here we demonstrate in a custom-designed UHV apparatus that the application of spatially extended, homogeneous, very high (>1 V nm(-1)) DC-fields not only changes the system energetics but triggers dynamic processes which become important much before static contributions appreciably modify the potential energy landscape. We take a well characterized ultrathin NiO film on a Ag(100) support as a proof-of-principle test case, and show how it gets reduced to supported Ni clusters under fields exceeding the threshold of +0.9 V nm(-1). Using an effective model, we trace the observed interfacial redox process down to a dissociative electron attachment resonant mechanism. The proposed approach can be easily implemented and generally applied to a wide range of interfacial systems, thus opening new opportunities for the manipulation of film growth and reaction processes at solid surfaces under strong external fields.

  2. De Novo Coding Variants Are Strongly Associated with Tourette Disorder.

    PubMed

    Willsey, A Jeremy; Fernandez, Thomas V; Yu, Dongmei; King, Robert A; Dietrich, Andrea; Xing, Jinchuan; Sanders, Stephan J; Mandell, Jeffrey D; Huang, Alden Y; Richer, Petra; Smith, Louw; Dong, Shan; Samocha, Kaitlin E; Neale, Benjamin M; Coppola, Giovanni; Mathews, Carol A; Tischfield, Jay A; Scharf, Jeremiah M; State, Matthew W; Heiman, Gary A

    2017-05-03

    Whole-exome sequencing (WES) and de novo variant detection have proven a powerful approach to gene discovery in complex neurodevelopmental disorders. We have completed WES of 325 Tourette disorder trios from the Tourette International Collaborative Genetics cohort and a replication sample of 186 trios from the Tourette Syndrome Association International Consortium on Genetics (511 total). We observe strong and consistent evidence for the contribution of de novo likely gene-disrupting (LGD) variants (rate ratio [RR] 2.32, p = 0.002). Additionally, de novo damaging variants (LGD and probably damaging missense) are overrepresented in probands (RR 1.37, p = 0.003). We identify four likely risk genes with multiple de novo damaging variants in unrelated probands: WWC1 (WW and C2 domain containing 1), CELSR3 (Cadherin EGF LAG seven-pass G-type receptor 3), NIPBL (Nipped-B-like), and FN1 (fibronectin 1). Overall, we estimate that de novo damaging variants in approximately 400 genes contribute risk in 12% of clinical cases. VIDEO ABSTRACT. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Experimental observation of strong coupling effects on the dispersion of dust acoustic waves in a plasma

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, P.; Prasad, G.; Sen, A.; Kaw, P. K.

    2007-09-01

    The dispersion properties of low frequency dust acoustic waves in the strong coupling regime are investigated experimentally in an argon plasma embedded with a mixture of kaolin and MnO2 dust particles. The neutral pressure is varied over a wide range to change the collisional properties of the dusty plasma. In the low collisional regime the turnover of the dispersion curve at higher wave numbers and the resultant region of ∂ω/∂k<0 are identified as signatures of dust dust correlations. In the high collisional regime dust neutral collisions produce a similar effect and prevent an unambiguous identification of strong coupling effects.

  4. Epidermal Expression and Regulation of Interleukin-33 during Homeostasis and Inflammation: Strong Species Differences.

    PubMed

    Sundnes, Olav; Pietka, Wojciech; Loos, Tamara; Sponheim, Jon; Rankin, Andrew L; Pflanz, Stefan; Bertelsen, Vibeke; Sitek, Jan C; Hol, Johanna; Haraldsen, Guttorm; Khnykin, Denis

    2015-07-01

    IL-33 is a novel IL-1 family member with a putative role in inflammatory skin disorders and a complex biology. Therefore, recent conflicting data regarding its function in experimental models justify a close assessment of its tissue expression and regulation. Indeed, we report here that there are strong species differences in the expression and regulation of epidermal IL-33. In murine epidermis, IL-33 behaved similar to an alarmin, being constitutively expressed in keratinocyte nuclei and rapidly lost during acute inflammation. By contrast, human and porcine IL-33 were weakly expressed or absent in keratinocytes of noninflamed skin but induced during acute inflammation. To this end, we observed that expression of IL-33 in human keratinocytes but not murine keratinocytes was strongly induced by IFN-γ, and this upregulation completely depended on the presence of EGFR ligands. Accordingly, IFN-γ increased the expression of IL-33 in the basal layers of the epidermis in human ex vivo skin cultures only, despite good evidence of IFN-γ activity in cultures from both species. Together these findings demonstrate that a full understanding of IL-33 function in clinical settings must take species-specific differences into account.

  5. Gemini long-slit observations of luminous obscured quasars: Further evidence for an upper limit on the size of the narrow-line region

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hainline, Kevin N.; Hickox, Ryan C.; Greene, Jenny E.

    2014-05-20

    We examine the spatial extent of the narrow-line regions (NLRs) of a sample of 30 luminous obscured quasars at 0.4 < z < 0.7 observed with spatially resolved Gemini-N GMOS long-slit spectroscopy. Using the [O III] λ5007 emission feature, we estimate the size of the NLR using a cosmology-independent measurement: the radius where the surface brightness falls to 10{sup –15} erg s{sup –1} cm{sup –2} arcsec{sup –2}. We then explore the effects of atmospheric seeing on NLR size measurements and conclude that direct measurements of the NLR size from observed profiles are too large by 0.1-0.2 dex on average, asmore » compared to measurements made to best-fit Sérsic or Voigt profiles convolved with the seeing. These data, which span a full order of magnitude in IR luminosity (log (L {sub 8} {sub μm}/erg s{sup –1}) = 44.4-45.4), also provide strong evidence that there is a flattening of the relationship between NLR size and active galactic nucleus luminosity at a seeing-corrected size of ∼7 kpc. The objects in this sample have high luminosities which place them in a previously under-explored portion of the size-luminosity relationship. These results support the existence of a maximal size of the NLR around luminous quasars; beyond this size, there is either not enough gas or the gas is over-ionized and does not produce enough [O III] λ5007 emission.« less

  6. Atomic and electronic structure of trilayer graphene/SiC(0001): Evidence of Strong Dependence on Stacking Sequence and charge transfer.

    PubMed

    Pierucci, Debora; Brumme, Thomas; Girard, Jean-Christophe; Calandra, Matteo; Silly, Mathieu G; Sirotti, Fausto; Barbier, Antoine; Mauri, Francesco; Ouerghi, Abdelkarim

    2016-09-15

    The transport properties of few-layer graphene are the directly result of a peculiar band structure near the Dirac point. Here, for epitaxial graphene grown on SiC, we determine the effect of charge transfer from the SiC substrate on the local density of states (LDOS) of trilayer graphene using scaning tunneling microscopy/spectroscopy and angle resolved photoemission spectroscopy (ARPES). Different spectra are observed and are attributed to the existence of two stable polytypes of trilayer: Bernal (ABA) and rhomboedreal (ABC) staking. Their electronic properties strongly depend on the charge transfer from the substrate. We show that the LDOS of ABC stacking shows an additional peak located above the Dirac point in comparison with the LDOS of ABA stacking. The observed LDOS features, reflecting the underlying symmetry of the two polytypes, were reproduced by explicit calculations within density functional theory (DFT) including the charge transfer from the substrate. These findings demonstrate the pronounced effect of stacking order and charge transfer on the electronic structure of trilayer or few layer graphene. Our approach represents a significant step toward understand the electronic properties of graphene layer under electrical field.

  7. Exploration of the Transition from the Hydrodynamic-like to the Strongly Kinetic Regime in Shock-Driven Implosions

    DOE PAGES

    Rosenberg, M. J.; Rinderknecht, H. G.; Hoffman, N. M.; ...

    2014-05-05

    Clear evidence of the transition from hydrodynamiclike to strongly kinetic shock-driven implosions is, for the first time, revealed and quantitatively assessed. Implosions with a range of initial equimolar D 3He gas densities show that as the density is decreased, hydrodynamic simulations strongly diverge from and increasingly over-predict the observed nuclear yields, from a factor of ~2 at 3.1 mg/cm 3 to a factor of 100 at 0.14 mg/cm 3. (The corresponding Knudsen number, the ratio of ion mean-free path to minimum shell radius, varied from 0.3 to 9; similarly, the ratio of fusion burn duration to ion diffusion time, anothermore » figure of merit of kinetic effects, varied from 0.3 to 14.) This result is shown to be unrelated to the effects of hydrodynamic mix. As a first step to garner insight into this transition, a reduced ion kinetic (RIK) model that includes gradient-diffusion and loss-term approximations to several transport processes was implemented within the framework of a one-dimensional radiation-transport code. After empirical calibration, the RIK simulations reproduce the observed yield trends, largely as a result of ion diffusion and the depletion of the reacting tail ions.« less

  8. Evaluating and Using Observational Evidence: The Contrasting Views of Policy Makers and Epidemiologists.

    PubMed

    O'Donoughue Jenkins, Lily; Kelly, Paul M; Cherbuin, Nicolas; Anstey, Kaarin J

    2016-01-01

    Currently, little is known about the types of evidence used by policy makers. This study aimed to investigate how policy makers in the health domain use and evaluate evidence and how this differs from academic epidemiologists. By having a better understanding of how policy makers select, evaluate, and use evidence, academics can tailor the way in which that evidence is produced, potentially leading to more effective knowledge translation. An exploratory mixed-methods study design was used. Quantitative measures were collected via an anonymous online survey ( n  = 28), with sampling from three health-related government and non-government organizations. Semi-structured interviews with policy makers ( n  = 20) and epidemiologists ( n  = 6) were conducted to gather qualitative data. Policy makers indicated systematic reviews were the preferred research resource (19%), followed closely by qualitative research (16%). Neither policy makers nor epidemiologists used grading instruments to evaluate evidence. In the web survey, policy makers reported that consistency and strength of evidence (93%), the quality of data (93%), bias in the evidence (79%), and recency of evidence (79%) were the most important factors taken into consideration when evaluating the available evidence. The same results were found in the qualitative interviews. Epidemiologists focused on the methodology used in the study. The most cited barriers to using robust evidence, according to policy makers, were political considerations (60%), time limitations (55%), funding (50%), and research not being applicable to current policies (50%). The policy maker's investigation did not report a systematic approach to evaluating evidence. Although there was some overlap between what policy makers and epidemiologists identified as high-quality evidence, there was also some important differences. This suggests that the best scientific evidence may not routinely be used in the development of policy. In

  9. Observations at Mercury encounter by the plasma science experiment on Mariner 10

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.; Scudder, J. D.; Hartle, R. E.; Siscoe, G. L.; Bridge, H. S.; Lazarus, A. J.; Asbridge, J. R.; Bame, S. J.; Yeates, C. M.

    1974-01-01

    A fully developed bow shock and magnetosheath were observed near Mercury, providing unambiguous evidence for a strong interaction between Mercury and the solar wind. Inside the sheath there is a distinct region analogous to the magnetosphere or magnetotail of earth, populated by electrons with lower density and higher temperature than the electrons observed in the solar wind or magnetosheath. At the time of encounter, conditions were such that a perpendicular shock was observed on the inbound leg and a parallel shock was observed on the outbound leg of the trajectory, and energetic plasma electron events were detected upstream from the outbound shock crossing. The interaction is most likely not atmospheric, but the data clearly indicate that the obstacle to solar wind flow is magnetic, either intrinsic or induced.

  10. A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision

    NASA Astrophysics Data System (ADS)

    Wang, Junfeng; Fabbiano, Giuseppina; Elvis, Martin; Risaliti, Guido; Mundell, Carole G.; Karovska, Margarita; Zezas, Andreas

    2011-07-01

    We have studied the X-ray emission within the inner ~150 pc radius of NGC 4151 by constructing high spatial resolution emission line images of blended O VII, O VIII, and Ne IX. These maps show extended structures that are spatially correlated with the radio outflow and optical [O III] emission. We find strong evidence for jet-gas cloud interaction, including morphological correspondences with regions of X-ray enhancement, peaks of near-infrared [Fe II] emission, and optical clouds. In these regions, moreover, we find evidence of elevated Ne IX/O VII ratios; the X-ray emission of these regions also exceeds that expected from nuclear photoionization. Spectral fitting reveals the presence of a collisionally ionized component. The thermal energy of the hot gas suggests that >~ 0.1% of the estimated jet power is deposited into the host interstellar medium through interaction between the radio jet and the dense medium of the circumnuclear region. We find possible pressure equilibrium between the collisionally ionized hot gas and the photoionized line-emitting cool clouds. We also obtain constraints on the extended iron and silicon fluorescent emission. Both lines are spatially unresolved. The upper limit on the contribution of an extended emission region to the Fe Kα emission is <~ 5% of the total, in disagreement with a previous claim that 65% of the Fe Kα emission originates in the extended narrow line region.

  11. Seismic evidence for widespread western-US deep-crustal deformation caused by extension

    USGS Publications Warehouse

    Moschetti, M.P.; Ritzwoller, M.H.; Lin, F.; Yang, Y.

    2010-01-01

    Laboratory experiments have established that many of the materials comprising the Earth are strongly anisotropic in terms of seismic-wave speeds. Observations of azimuthal and radial anisotropy in the upper mantle are attributed to the lattice-preferred orientation of olivine caused by the shear strains associated with deformation, and provide some of the most direct evidence for deformation and flow within the Earths interior. Although observations of crustal radial anisotropy would improve our understanding of crustal deformation and flow patterns resulting from tectonic processes, large-scale observations have been limited to regions of particularly thick crust. Here we show that observations from ambient noise tomography in the western United States reveal strong deep (middle to lower)-crustal radial anisotropy that is confined mainly to the geological provinces that have undergone significant extension during the Cenozoic Era (since 65 Myr ago). The coincidence of crustal radial anisotropy with the extensional provinces of the western United States suggests that the radial anisotropy results from the lattice-preferred orientation of anisotropic crustal minerals caused by extensional deformation. These observations also provide support for the hypothesis that the deep crust within these regions has undergone widespread and relatively uniform strain in response to crustal thinning and extension. ?? 2010 Macmillan Publishers Limited. All rights reserved.

  12. Local cooling and warming effects of forests based on satellite observations

    PubMed Central

    Li, Yan; Zhao, Maosheng; Motesharrei, Safa; Mu, Qiaozhen; Kalnay, Eugenia; Li, Shuangcheng

    2015-01-01

    The biophysical effects of forests on climate have been extensively studied with climate models. However, models cannot accurately reproduce local climate effects due to their coarse spatial resolution and uncertainties, and field observations are valuable but often insufficient due to their limited coverage. Here we present new evidence acquired from global satellite data to analyse the biophysical effects of forests on local climate. Results show that tropical forests have a strong cooling effect throughout the year; temperate forests show moderate cooling in summer and moderate warming in winter with net cooling annually; and boreal forests have strong warming in winter and moderate cooling in summer with net warming annually. The spatiotemporal cooling or warming effects are mainly driven by the two competing biophysical effects, evapotranspiration and albedo, which in turn are strongly influenced by rainfall and snow. Implications of our satellite-based study could be useful for informing local forestry policies. PMID:25824529

  13. Fragility and super-strong character of non-stoichiometric chalcogenides: implications on melt homogenization

    NASA Astrophysics Data System (ADS)

    Ravindren, Sriram; Gunasekera, Kapila; Boolchand, Punit; Micoulaut, Matthieu

    2014-03-01

    The kinetics of homogenization of binary AsxSe100-x melts in the As concentration range 0% strong nature of melt compositions in 20% observed slow kinetics of melt homogenization. In comparing these results with earlier reports, there is evidence that fragility decreases as melts are homogenized. Furthermore, a clear scaling of m vs. Tg is observed with a negative slope for Flexible glasses and a positive slope for Rigid and Stressed-rigid ones. The absence of a melting endotherm in non-stoichiometric As-Se compositions is reported. Fragilities of the Ge-As-Se are reported and a correlation observed with fragilities of As-Se and Ge-Se. Supported by NSF grant DMR 08-53957.

  14. Non-LTE profiles of strong solar lines

    NASA Technical Reports Server (NTRS)

    Schneeberger, T. J.; Beebe, H. A.

    1976-01-01

    The complete linearization method is applied to the formation of strong lines in the solar atmosphere. Transitions in Na(I), Mg(I), Ca(I), Mg(II), and Ca(II) are computed with a standard atmosphere and microturbulent velocity model. The computed profiles are compared to observations at disk center.

  15. Observing the First Stars in Luminous, Red Galaxies

    NASA Technical Reports Server (NTRS)

    Heap, Sally; Lindler, Don

    2010-01-01

    Modern cosmological simulations predict that the first stars are to be found today in luminous, red galaxies. Although observing such stars individually against a background of younger, metal-rich stars is impossible, the first stars should make their presence known by their strong, line-free ultraviolet flux. We have found evidence for a UV-bright stellar population in Sloan spectra of LRG's at z=0.4-0.5. We present arguments for interpreting this UV-bright stellar population as the oldest stars, rather than other types of stellar populations (e.g. young stars or blue straggler stars in the dominant, metal-rich stellar population

  16. The Tropopause Inversion Layer: New Observations, New Theories

    NASA Astrophysics Data System (ADS)

    Tandon, N.; Randel, W. J.; Pan, L.; Son, S.; Polvani, L. M.

    2009-12-01

    There is now great interest in the tropopause inversion inversion layer (TIL), a 1-2 km region just above the tropopause where there is a spike in static stability. Radio occultation data from the COSMIC GPS mission are providing an unprecedented level of spatial and temporal resolution with which to analyze the TIL. We start by showing the agreement between GPS data and radiosondes. We then examine the causes and consequences of the TIL. Observations from the ACE satellite and fixed dynamical heating calculations suggest strong roles for water vapor and ozone in the formation and modulation of the TIL. This agrees with observations showing a large TIL in the polar winter, where water vapor levels are persistently high. It is also clear that TIL strength is related to vorticity, but observations and models have important differences that need to be reconciled. These dynamical considerations dovetail with observations showing high TIL variability in the storm-track regions. Finally there is evidence from ozonesonde data that the TIL may be coupled to transport across the tropopause.

  17. Observations of pockmark flow structure in Belfast Bay, Maine, Part 2: evidence for cavity flow

    USGS Publications Warehouse

    Fandel, Christina L.; Lippmann, Thomas C.; Foster, Diane L.; Brothers, Laura L.

    2017-01-01

    Pockmark flow circulation patterns were investigated through current measurements along the rim and center of two pockmarks in Belfast Bay, Maine. Observed time-varying current profiles have a complex vertical and directional structure that rotates significantly with depth and is strongly dependent on the phase of the tide. Observations of the vertical profiles of horizontal velocities in relation to relative geometric parameters of the pockmark are consistent with circulation patterns described qualitatively by cavity flow models (Ashcroft and Zhang 2005). The time-mean behavior of the shear layer is typically used to characterize cavity flow, and was estimated using vorticity thickness to quantify the growth rate of the shear layer horizontally across the pockmark. Estimated positive vorticity thickness spreading rates are consistent with cavity flow predictions, and occur at largely different rates between the two pockmarks. Previously modeled flow (Brothers et al. 2011) and laboratory measurements (Pau et al. 2014) over pockmarks of similar geometry to those examined herein are also qualitatively consistent with cavity flow circulation, suggesting that cavity flow may be a good first-order flow model for pockmarks in general.

  18. Evidence for impact ionization in vanadium dioxide

    DOE PAGES

    Holleman, Joshua; Bishop, Michael M.; Garcia, Carlos; ...

    2016-10-17

    Pump-probe optical spectroscopy was used to investigate charge carrier multiplication via impact ionization in the M 1 insulating phase of VO 2. By comparing the transient reflectivities of the film when pumped at less than and then more than twice the band-gap energy, we observed an enhancement of the ultrafast response with the higher energy pump color while the film was still transiently in the insulating phase. We additionally identified multiple timescales within the charge dynamics and analyzed how these changed when the pump and probe wavelengths were varied. This experiment provided evidence that impact ionization acts efficiently as amore » carrier multiplication process in this prototypical strongly-correlated insulator.« less

  19. Physics in strong magnetic fields near neutron stars

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.

    1991-01-01

    Electromagnetic phenomena occurring in the strong magnetic fields of neutron stars are currently of great interest in high-energy astrophysics. Observations of rotation rate changes and cyclotron lines in pulsars and gamma-ray bursts indicate that surface magnetic fields of neutron stars often exceed a trillion gauss. In fields this strong, where electrons behave much as if they were in bound atomic states, familiar processes undergo profound changes, and exotic processes become important. Strong magnetic fields affect the physics in several fundamental ways: energies perpendicular to the field are quantized, transverse momentum is not conserved, and electron-positron spin is important. Neutron stars therefore provide a unique laboratory for the study of physics in extremely high fields that cannot be generated on earth.

  20. Observational selection biases in time-delay strong lensing and their impact on cosmography

    NASA Astrophysics Data System (ADS)

    Collett, Thomas E.; Cunnington, Steven D.

    2016-11-01

    Inferring cosmological parameters from time-delay strong lenses requires a significant investment of telescope time; it is therefore tempting to focus on the systems with the brightest sources, the highest image multiplicities and the widest image separations. We investigate if this selection bias can influence the properties of the lenses studied and the cosmological parameters inferred. Using an ellipsoidal power-law deflector population, we build a sample of double- and quadruple-image systems. Assuming reasonable thresholds on image separation and flux, based on current lens monitoring campaigns, we find that the typical density profile slopes of monitorable lenses are significantly shallower than the input ensemble. From a sample of quads, we find that this selection function can introduce a 3.5 per cent bias on the inferred time-delay distances if the properties of the input ensemble are (incorrectly) used as priors on the lens model. This bias remains at the 2.4 per cent level when high-resolution imaging of the quasar host is used to precisely infer the properties of individual lenses. We also investigate if the lines of sight for monitorable strong lenses are biased. The expectation value for the line-of-sight convergence is increased by 0.009 (0.004) for quads (doubles) implying a 0.9 per cent (0.4 per cent) bias on H0. We therefore conclude that whilst the properties of typical quasar lenses and their lines of sight do deviate from the global population, the total magnitude of this effect is likely to be a subdominant effect for current analyses, but has the potential to be a major systematic for samples of ˜25 or more lenses.

  1. Strong Pitch-Angle Diffusion of Ring Current Ions in Geomagnetic Storm-Associated Conditions

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Gallagher, D. L.; Spann, J. F.

    2005-01-01

    Do electromagnetic ion cyclotron (EMIC) waves cause strong pitch-angle diffusion of RC ions? This question is the primary motivation of this paper and has been affirmatively answered from the theoretical point of view. The materials that are presented in the Results section show clear evidence that strong pitch-angle diffusion takes place in the inner magnetosphere indicating an important role for the wave-particle interaction mechanism in the formation of RC ions and EMIC waves.

  2. Observations of faint comets with the IUE

    NASA Astrophysics Data System (ADS)

    Festou, M.

    1982-06-01

    Spectral observations of eight comets, including seven periodic comets, made in the range 1150-3400 A with the IUE satellite are presented. Comet Bradfield, the sole nonperiodic comet observed, is found to exhibit strong OH and atomic hydrogen emissions from the decomposition of water, along with oxygen, carbon, sulfur, carbon disulfide, C2 and CO2(plus) emissions and a faint continuum due to dust at longer wavelengths. Comets Encke, Tuttle and Stefan-Oterma appear to have identical spectra in the UV, showing evidence of much gas, little dust and few ions (only CO2(plus) detected), and differing from comet Bradfield only in the lack of C2 emission. All eight comets observed by IUE, including Seargent, Meier, Borrelly and Panther, had the same chemical composition, consisting mainly of water with a few per mil or per cent CN, C2, C3 and CS. The water production rates of the periodic comets range from levels 6 times less to 11 times more than that of Comet Bradfield, which may be related to nuclear size or cometary age.

  3. Crossover from weak to strong localization in quasi-1D = conductors.

    NASA Astrophysics Data System (ADS)

    Gershenson, M. E.; Khavin, Y. B.; Mikhalchuk, A. G.; Bozler, H. M.; Bogdanov, A. L.

    1997-03-01

    A crossover from weak localization (WL) to strong localization (SL) with decreasing temperature has been observed in the resistance of quasi-1D channels in Si delta-doped GaAs structures. The crossover occurs when the phase-breaking length becomes comparable to the localization length. In the SL regime, an activation temperature dependence R(T) is observed. The activation energy is very close to the spacing between the energy levels of the localized electrons within the localization domain. The activation energy decreases by half in strong magnetic fields, as a result, an exponentially strong negative magnetoresistance is developed. All the features of the magnetoresistance in the SL regime are in good agreement with the theory of doubling of the localization length in quasi-1D conductors in strong fields. The magnetoresistance provides a direct measurement of the localization length. Supported by RNFBR, INTAS 943862, and NSF DRM-9623716 (A.G.M. and H.M.B.)

  4. Observations of magnetospheric ionization enhancements using upper-hybrid resonance noise band data from the RAE-1 satellite

    NASA Technical Reports Server (NTRS)

    Mosier, S. R.

    1975-01-01

    Noise bands associated with the upper-hybrid resonance were used to provide direct evidence for the existence of regions of enhanced density in the equatorial magnetosphere near L = 2. Density enhancements ranging from several percent to as high as 45 percent are observed with radial dimensions of several hundred kilometers. The enhancement characteristics strongly suggest their identification as magnetospheric whistler ducts.

  5. Mixtures of Strongly Interacting Bosons in Optical Lattices

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Buonsante, P.; Penna, V.; Giampaolo, S. M.

    2008-06-20

    We investigate the properties of strongly interacting heteronuclear boson-boson mixtures loaded in realistic optical lattices, with particular emphasis on the physics of interfaces. In particular, we numerically reproduce the recent experimental observation that the addition of a small fraction of {sup 41}K induces a significant loss of coherence in {sup 87}Rb, providing a simple explanation. We then investigate the robustness against the inhomogeneity typical of realistic experimental realizations of the glassy quantum emulsions recently predicted to occur in strongly interacting boson-boson mixtures on ideal homogeneous lattices.

  6. Strong Clustering of Lyman Break Galaxies around Luminous Quasars at Z ˜ 4

    NASA Astrophysics Data System (ADS)

    García-Vergara, Cristina; Hennawi, Joseph F.; Barrientos, L. Felipe; Rix, Hans-Walter

    2017-10-01

    In the standard picture of structure formation, the first massive galaxies are expected to form at the highest peaks of the density field, which constitute the cores of massive proto-clusters. Luminous quasars (QSOs) at z ˜ 4 are the most strongly clustered population known, and should thus reside in massive dark matter halos surrounded by large overdensities of galaxies, implying a strong QSO-galaxy cross-correlation function. We observed six z ˜ 4 QSO fields with VLT/FORS, exploiting a novel set of narrow-band filters custom designed to select Lyman Break Galaxies (LBGs) in a thin redshift slice of {{Δ }}z˜ 0.3, mitigating the projection effects that have limited the sensitivity of previous searches for galaxies around z≳ 4 QSOs. We find that LBGs are strongly clustered around QSOs, and present the first measurement of the QSO-LBG cross-correlation function at z ˜ 4, on scales of 0.1≲ R≲ 9 {h}-1 {Mpc} (comoving). Assuming a power-law form for the cross-correlation function ξ ={(r/{r}0{QG})}γ , we measure {r}0{QG}={8.83}-1.51+1.39 {h}-1 {Mpc} for a fixed slope of γ =2.0. This result is in agreement with the expected cross-correlation length deduced from measurements of the QSO and LBG auto-correlation function, and assuming a deterministic bias model. We also measure a strong auto-correlation of LBGs in our QSO fields, finding {r}0{GG}={21.59}-1.69+1.72 {h}-1 {Mpc} for a fixed slope of γ =1.5, which is ˜4 times larger than the LBG auto-correlation length in blank fields, providing further evidence that QSOs reside in overdensities of LBGs. Our results qualitatively support a picture where luminous QSOs inhabit exceptionally massive ({M}{halo}> {10}12 {M}⊙ ) dark matter halos at z ˜ 4.

  7. Observational Study Designs for Comparative Effectiveness Research: An Alternative Approach to Close Evidence Gaps in Head-and-Neck Cancer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goulart, Bernardo H.L., E-mail: bhg@uw.edu; University of Washington, Seattle, Washington; Ramsey, Scott D.

    Comparative effectiveness research (CER) has emerged as an approach to improve quality of care and patient outcomes while reducing healthcare costs by providing evidence to guide healthcare decisions. Randomized controlled trials (RCTs) have represented the ideal study design to support treatment decisions in head-and-neck (H and N) cancers. In RCTs, formal chance (randomization) determines treatment allocation, which prevents selection bias from distorting the measure of treatment effects. Despite this advantage, only a minority of patients qualify for inclusion in H and N RCTs, which limits the validity of their results to the broader H and N cancer patient population seenmore » in clinical practice. Randomized controlled trials often do not address other knowledge gaps in the management of H and N cancer, including treatment comparisons for rare types of H and N cancers, monitoring of rare or late toxicity events (eg, osteoradionecrosis), or in some instances an RCT is simply not feasible. Observational studies, or studies in which treatment allocation occurs independently of investigators' choice or randomization, may address several of these gaps in knowledge, thereby complementing the role of RCTs. This critical review discusses how observational CER studies complement RCTs in generating the evidence to inform healthcare decisions and improve the quality of care and outcomes of H and N cancer patients. Review topics include a balanced discussion about the strengths and limitations of both RCT and observational CER study designs; a brief description of design and analytic techniques to handle selection bias in observational studies; examples of observational studies that inform current clinical practices and management of H and N cancers; and suggestions for relevant CER questions that could be addressed by an observational study design.« less

  8. Observational study designs for comparative effectiveness research: an alternative approach to close evidence gaps in head-and-neck cancer.

    PubMed

    Goulart, Bernardo H L; Ramsey, Scott D; Parvathaneni, Upendra

    2014-01-01

    Comparative effectiveness research (CER) has emerged as an approach to improve quality of care and patient outcomes while reducing healthcare costs by providing evidence to guide healthcare decisions. Randomized controlled trials (RCTs) have represented the ideal study design to support treatment decisions in head-and-neck (H&N) cancers. In RCTs, formal chance (randomization) determines treatment allocation, which prevents selection bias from distorting the measure of treatment effects. Despite this advantage, only a minority of patients qualify for inclusion in H&N RCTs, which limits the validity of their results to the broader H&N cancer patient population seen in clinical practice. Randomized controlled trials often do not address other knowledge gaps in the management of H&N cancer, including treatment comparisons for rare types of H&N cancers, monitoring of rare or late toxicity events (eg, osteoradionecrosis), or in some instances an RCT is simply not feasible. Observational studies, or studies in which treatment allocation occurs independently of investigators' choice or randomization, may address several of these gaps in knowledge, thereby complementing the role of RCTs. This critical review discusses how observational CER studies complement RCTs in generating the evidence to inform healthcare decisions and improve the quality of care and outcomes of H&N cancer patients. Review topics include a balanced discussion about the strengths and limitations of both RCT and observational CER study designs; a brief description of design and analytic techniques to handle selection bias in observational studies; examples of observational studies that inform current clinical practices and management of H&N cancers; and suggestions for relevant CER questions that could be addressed by an observational study design. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Strong claims and weak evidence: reassessing the predictive validity of the IAT.

    PubMed

    Blanton, Hart; Jaccard, James; Klick, Jonathan; Mellers, Barbara; Mitchell, Gregory; Tetlock, Philip E

    2009-05-01

    The authors reanalyzed data from 2 influential studies-A. R. McConnell and J. M. Leibold and J. C. Ziegert and P. J. Hanges-that explore links between implicit bias and discriminatory behavior and that have been invoked to support strong claims about the predictive validity of the Implicit Association Test. In both of these studies, the inclusion of race Implicit Association Test scores in regression models reduced prediction errors by only tiny amounts, and Implicit Association Test scores did not permit prediction of individual-level behaviors. Furthermore, the results were not robust when the impact of rater reliability, statistical specifications, and/or outliers were taken into account, and reanalysis of A. R. McConnell & J. M. Leibold (2001) revealed a pattern of behavior consistent with a pro-Black behavioral bias, rather than the anti-Black bias suggested in the original study. (c) 2009 APA, all rights reserved.

  10. Satellite Observations of Stratospheric Gravity Waves Associated With the Intensification of Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Hoffmann, Lars; Wu, Xue; Alexander, M. Joan

    2018-02-01

    Forecasting the intensity of tropical cyclones is a challenging problem. Rapid intensification is often preceded by the formation of "hot towers" near the eyewall. Driven by strong release of latent heat, hot towers are high-reaching tropical cumulonimbus clouds that penetrate the tropopause. Hot towers are a potentially important source of stratospheric gravity waves. Using 13.5 years (2002-2016) of Atmospheric Infrared Sounder observations of stratospheric gravity waves and tropical cyclone data from the International Best Track Archive for Climate Stewardship, we found empirical evidence that stratospheric gravity wave activity is associated with the intensification of tropical cyclones. The Atmospheric Infrared Sounder and International Best Track Archive for Climate Stewardship data showed that strong gravity wave events occurred about twice as often for tropical cyclone intensification compared to storm weakening. Observations of stratospheric gravity waves, which are not affected by obscuring tropospheric clouds, may become an important future indicator of storm intensification.

  11. Strong non-radial propagation of energetic electrons in solar corona

    NASA Astrophysics Data System (ADS)

    Klassen, A.; Dresing, N.; Gómez-Herrero, R.; Heber, B.; Veronig, A.

    2018-06-01

    Analyzing the sequence of solar energetic electron events measured at both STEREO-A (STA) and STEREO-B (STB) spacecraft during 17-21 July 2014, when their orbital separation was 34°, we found evidence of a strong non-radial electron propagation in the solar corona below the solar wind source surface. The impulsive electron events were associated with recurrent flare and jet (hereafter flare/jet) activity at the border of an isolated coronal hole situated close to the solar equator. We have focused our study on the solar energetic particle (SEP) event on 17 July 2014, during which both spacecraft detected a similar impulsive and anisotropic energetic electron event suggesting optimal connection of both spacecraft to the parent particle source, despite the large angular separation between the parent flare and the nominal magnetic footpoints on the source surface of STA and STB of 68° and 90°, respectively. Combining the remote-sensing extreme ultraviolet (EUV) observations, in-situ plasma, magnetic field, and energetic particle data we investigated and discuss here the origin and the propagation trajectory of energetic electrons in the solar corona. We find that the energetic electrons in the energy range of 55-195 keV together with the associated EUV jet were injected from the flare site toward the spacecraft's magnetic footpoints and propagate along a strongly non-radial and inclined magnetic field below the source surface. From stereoscopic (EUV) observations we estimated the inclination angle of the jet trajectory and the respective magnetic field of 63° ± 11° relative to the radial direction. We show how the flare accelerated electrons reach very distant longitudes in the heliosphere, when the spacecraft are nominally not connected to the particle source. This example illustrates how ballistic backmapping can occasionally fail to characterize the magnetic connectivity during SEP events. This finding also provides an additional mechanism (one among others

  12. Fragile-to-strong transition in liquid silica

    NASA Astrophysics Data System (ADS)

    Geske, Julian; Drossel, Barbara; Vogel, Michael

    2016-03-01

    We investigate anomalies in liquid silica with molecular dynamics simulations and present evidence for a fragile-to-strong transition at around 3100 K-3300 K. To this purpose, we studied the structure and dynamical properties of silica over a wide temperature range, finding four indicators of a fragile-to-strong transition. First, there is a density minimum at around 3000 K and a density maximum at 4700 K. The turning point is at 3400 K. Second, the local structure characterized by the tetrahedral order parameter changes dramatically around 3000 K from a higher-ordered, lower-density phase to a less ordered, higher-density phase. Third, the correlation time τ changes from an Arrhenius behavior below 3300 K to a Vogel-Fulcher-Tammann behavior at higher temperatures. Fourth, the Stokes-Einstein relation holds for temperatures below 3000 K, but is replaced by a fractional relation above this temperature. Furthermore, our data indicate that dynamics become again simple above 5000 K, with Arrhenius behavior and a classical Stokes-Einstein relation.

  13. Evidence for glaciation in Elysium

    NASA Technical Reports Server (NTRS)

    Anderson, Duwayne M.; Brandstrom, Gary W.

    1987-01-01

    It is suggested that certain landforms in the Elysium region of Mars provide strong evidence for glaciation. Landscapes related to subglacial volcanism suggest that ice was a primary agent in the development of Elysium.

  14. Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

    DOE PAGES

    Miller, A. A.; Cao, Y.; Piro, A. L.; ...

    2018-01-11

    Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is when the SN could have first been detected by our survey, occurred onlymore » $$0.15\\pm_{0.07}^{0.15}$$ days before our first detection. In the $$\\sim$$24 hr after discovery, iPTF 16abc rose by $$\\sim$$2 mag, featuring a near-linear rise in flux for $$\\gtrsim$$3 days. Early spectra show strong C II absorption, which disappears after $$\\sim$$7 days. Unlike the extensivelyobserved SN Ia SN 2011fe, the $$(B-V)_0$$ colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. Finally, in the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.« less

  15. Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, A. A.; Cao, Y.; Piro, A. L.

    Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is when the SN could have first been detected by our survey, occurred onlymore » $$0.15\\pm_{0.07}^{0.15}$$ days before our first detection. In the $$\\sim$$24 hr after discovery, iPTF 16abc rose by $$\\sim$$2 mag, featuring a near-linear rise in flux for $$\\gtrsim$$3 days. Early spectra show strong C II absorption, which disappears after $$\\sim$$7 days. Unlike the extensivelyobserved SN Ia SN 2011fe, the $$(B-V)_0$$ colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. Finally, in the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.« less

  16. Fundamental parameters of He-weak and He-strong stars

    NASA Astrophysics Data System (ADS)

    Cidale, L. S.; Arias, M. L.; Torres, A. F.; Zorec, J.; Frémat, Y.; Cruzado, A.

    2007-06-01

    Context: He-weak and He-strong stars are chemically peculiar AB objects whose He lines are anomalously weak or strong for their MK spectral type. The determination of fundamental parameters for these stars is often more complex than for normal stars due to their abundance anomalies. Aims: We discuss the determination of fundamental parameters: effective temperature, surface gravity, and visual and bolometric absolute magnitudes of He-weak and He-strong stars. We compare our values with those derived independently from methods based on photometry and model fitting. Methods: We carried out low resolution spectroscopic observations in the wavelength range 3400-4700 Å of 20 He-weak and 8 He-strong stars to determine their fundamental parameters by means of the Divan-Chalonge-Barbier (BCD) spectrophotometric system. This system is based on the measurement of the continuum energy distribution around the Balmer discontinuity (BD). For a few He-weak stars we also estimate the effective temperatures and the angular diameters by integrating absolute fluxes observed over a wide spectral range. Non-LTE model calculations are carried out to study the influence of the He/H abundance ratio on the emergent radiation of He-strong stars and on their T_eff determination. Results: We find that the effective temperatures, surface gravities and bolometric absolute magnitudes of He-weak stars estimated with the BCD system and the integrated flux method are in good agreement between each other, and they also agree with previous determinations based on several different methods. The mean discrepancy between the visual absolute magnitudes derived using the hipparcos parallaxes and the BCD values is on average ±0.3 mag for He-weak stars, while it is ±0.5 mag for He-strong stars. For He-strong stars, we note that the BCD calibration, based on stars in the solar environment, leads to overestimated values of T_eff. By means of model atmosphere calculations with enhanced He/H abundance ratios

  17. Constraints on cosmological models from strong gravitational lensing systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cao, Shuo; Pan, Yu; Zhu, Zong-Hong

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances D{sub ds}/D{sub s} from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combiningmore » stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models (ΛCDM, constant w and CPL) under a flat universe assumption. For the full sample (n = 80) and the restricted sample (n = 46) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future.« less

  18. Dynamical observation and detailed description of catalysts under strong metal–support interaction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Shuyi; Plessow, Philipp N.; Willis, Joshua J.

    2016-06-09

    Understanding the structures of catalysts under realistic conditions with atomic precision is crucial to design better materials for challenging transformations. Under reducing conditions, certain reducible supports migrate onto supported metallic particles and create strong metal–support states that drastically change the reactivity of the systems. The details of this process are still unclear and preclude its thorough exploitation. Here, we report an atomic description of a palladium/titania (Pd/TiO 2) system by combining state-of-the-art in situ transmission electron microscopy and density functional theory (DFT) calculations with structurally defined materials, in which we visualize the formation of the overlayers at the atomic scalemore » under atmospheric pressure and high temperature. We show that an amorphous reduced titania layer is formed at low temperatures, and that crystallization of the layer into either mono- or bilayer structures is dictated by the reaction environment and predicted by theory. Moreover, it occurs in combination with a dramatic reshaping of the metallic surface facets.« less

  19. A Strong Merger Shock in Abell 665

    NASA Technical Reports Server (NTRS)

    Dasadia, S.; Sun, M.; Sarazin, C.; Morandi, A.; Markevitch, M.; Wik, D.; Feretti, L.; Giovannini, G.; Govoni, F.

    2016-01-01

    Deep (103 ks) Chandra observations of Abell 665 have revealed rich structures in this merging galaxy cluster, including a strong shock and two cold fronts. The newly discovered shock has a Mach number of M =?3.0 +/- 0.6, propagating in front of a cold disrupted cloud. This makes Abell 665 the second cluster, after the Bullet cluster, where a strong merger shock of M is approximately 3 has been detected. The shock velocity from jump conditions is consistent with (2.7 +/- 0.7) × 10(exp 3) km s(exp -1). The new data also reveal a prominent southern cold front with potentially heated gas ahead of it. Abell 665 also hosts a giant radio halo. There is a hint of diffuse radio emission extending to the shock at the north, which needs to be examined with better radio data. This new strong shock provides a great opportunity to study the reacceleration model with the X-ray and radio data combined.

  20. On the Contribution of Large-Scale Structure to Strong Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Faure, C.; Kneib, J.-P.; Hilbert, S.; Massey, R.; Covone, G.; Finoguenov, A.; Leauthaud, A.; Taylor, J. E.; Pires, S.; Scoville, N.; Koekemoer, Anton M.

    2009-04-01

    We study the correlation between the locations of galaxy-galaxy strong-lensing candidates and tracers of large-scale structure from both weak lensing (WL) or X-ray emission. The Cosmological Evolution Survey (COSMOS) is a unique data set, combining deep, high resolution and contiguous imaging in which strong lenses have been discovered, plus unparalleled multiwavelength coverage. To help interpret the COSMOS data, we have also produced mock COSMOS strong- and WL observations, based on ray-tracing through the Millennium Simulation. In agreement with the simulations, we find that strongly lensed images with the largest angular separations are found in the densest regions of the COSMOS field. This is explained by a prevalence among the lens population in dense environments of elliptical galaxies with high total-to-stellar mass ratios, which can deflect light through larger angles. However, we also find that the overall fraction of elliptical galaxies with strong gravitational lensing is independent of the local mass density; this observation is not true of the simulations, which predict an increasing fraction of strong lenses in dense environments. The discrepancy may be a real effect, but could also be explained by various limitations of our analysis. For example, our visual search of strong lens systems could be incomplete and suffer from selection bias; the luminosity function of elliptical galaxies may differ between our real and simulated data; or the simplifying assumptions and approximations used in our lensing simulations may be inadequate. Work is therefore ongoing. Automated searches for strong lens systems will be particularly important in better constraining the selection function.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cauley, P. Wilson; Redfield, Seth; Jensen, Adam G., E-mail: pcauley@wesleyan.edu

    2017-04-01

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

  2. Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

    NASA Astrophysics Data System (ADS)

    Sharon, Keren; Gladders, Michael D.; Rigby, Jane R.; Bayliss, Matthew B.; Wuyts, Eva; Dahle, Håkon; Johnson, Traci L.; Florian, Michael K.; Dunham, Samuel; Murray, Katherine; Whitaker, Kate; Li, Nan

    Driven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to 0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most ``famous'' strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

  3. Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

    NASA Astrophysics Data System (ADS)

    Sharon, Keren

    2015-08-01

    Driven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to ~0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most "famous" strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

  4. Observing golden-mean universality class in the scaling of thermal transport.

    PubMed

    Xiong, Daxing

    2018-02-01

    We address the issue of whether the golden-mean [ψ=(sqrt[5]+1)/2≃1.618] universality class, as predicted by several theoretical models, can be observed in the dynamical scaling of thermal transport. Remarkably, we show strong evidence that ψ appears to be the scaling exponent of heat mode correlation in a purely quartic anharmonic chain. This observation seems to somewhat deviate from the previous expectation and we explain it by the unusual slow decay of the cross correlation between heat and sound modes. Whenever the cubic anharmonicity is included, this cross correlation gradually dies out and another universality class with scaling exponent γ=5/3, as commonly predicted by theories, seems recovered. However, this recovery is accompanied by two interesting phase transition processes characterized by a change of symmetry of the potential and a clear variation of the dynamic structure factor, respectively. Due to these transitions, an additional exponent close to γ≃1.580 emerges. All this evidence suggests that, to gain a full prediction of the scaling of thermal transport, more ingredients should be taken into account.

  5. Observing golden-mean universality class in the scaling of thermal transport

    NASA Astrophysics Data System (ADS)

    Xiong, Daxing

    2018-02-01

    We address the issue of whether the golden-mean [ψ =(√{5 }+1 ) /2 ≃1.618 ] universality class, as predicted by several theoretical models, can be observed in the dynamical scaling of thermal transport. Remarkably, we show strong evidence that ψ appears to be the scaling exponent of heat mode correlation in a purely quartic anharmonic chain. This observation seems to somewhat deviate from the previous expectation and we explain it by the unusual slow decay of the cross correlation between heat and sound modes. Whenever the cubic anharmonicity is included, this cross correlation gradually dies out and another universality class with scaling exponent γ =5 /3 , as commonly predicted by theories, seems recovered. However, this recovery is accompanied by two interesting phase transition processes characterized by a change of symmetry of the potential and a clear variation of the dynamic structure factor, respectively. Due to these transitions, an additional exponent close to γ ≃1.580 emerges. All this evidence suggests that, to gain a full prediction of the scaling of thermal transport, more ingredients should be taken into account.

  6. Preliminary analysis of strong-motion recordings from the 28 September 2004 Parkfield, California earthquake

    USGS Publications Warehouse

    Shakal, A.; Graizer, V.; Huang, M.; Borcherdt, R.; Haddadi, H.; Lin, K.-W.; Stephens, C.; Roffers, P.

    2005-01-01

    The Parkfield 2004 earthquake yielded the most extensive set of strong-motion data in the near-source region of a magnitude 6 earthquake yet obtained. The recordings of acceleration and volumetric strain provide an unprecedented document of the near-source seismic radiation for a moderate earthquake. The spatial density of the measurements alon g the fault zone and in the linear arrays perpendicular to the fault is expected to provide an exceptional opportunity to develop improved models of the rupture process. The closely spaced measurements should help infer the temporal and spatial distribution of the rupture process at much higher resolution than previously possible. Preliminary analyses of the peak a cceleration data presented herein shows that the motions vary significantly along the rupture zone, from 0.13 g to more than 2.5 g, with a map of the values showing that the larger values are concentrated in three areas. Particle motions at the near-fault stations are consistent with bilateral rupture. Fault-normal pulses similar to those observed in recent strike-slip earthquakes are apparent at several of the stations. The attenuation of peak ground acceleration with distance is more rapid than that indicated by some standard relationships but adequately fits others. Evidence for directivity in the peak acceleration data is not strong. Several stations very near, or over, the rupturing fault recorded relatively low accelerations. These recordings may provide a quantitative basis to understand observations of low near-fault shaking damage that has been reported in other large strike-slip earthquak.

  7. A Correlation Between Length of Strong-Shear Neutral Lines and Total X-Ray Brightness in Active Regions

    NASA Technical Reports Server (NTRS)

    Falconer, D. A.

    1997-01-01

    From a sample of 7 MSFC vector magnetograms,of active regions and 17 Yohkoh SXT soft X-ray images of these active regions, we have found that the total x-ray brightness of an entire active region is correlated with the total length of neutral lines on which the magnetic field is both strong (less than 250 G) and strongly sheared (shear angle greater than 75 deg) in the same active region. This correlation, if not fortuitous, is additional evidence of the importance of strong-shear strong-field neutral lines to strong heating in active regions.

  8. Strong correlations in gravity and biophysics

    NASA Astrophysics Data System (ADS)

    Krotov, Dmitry

    The unifying theme of this dissertation is the use of correlations. In the first part (chapter 2), we investigate correlations in quantum field theories in de Sitter space. In the second part (chapters 3,4,5), we use correlations to investigate a theoretical proposal that real (observed in nature) transcriptional networks of biological organisms are operating at a critical point in their phase diagram. In chapter 2 we study the infrared dependence of correlators in various external backgrounds. Using the Schwinger-Keldysh formalism we calculate loop corrections to the correlators in the case of the Poincare patch and the complete de Sitter space. In the case of the Poincare patch, the loop correction modifies the behavior of the correlator at large distances. In the case of the complete de Sitter space, the loop correction has a strong dependence on the infrared cutoff in the past. It grows linearly with time, suggesting that at some point the correlations become strong and break the symmetry of the classical background. In chapter 3 we derive the signatures of critical behavior in a model organism, the embryo of Drosophila melanogaster. They are: strong correlations in the fluctuations of different genes, a slowing of dynamics, long range correlations in space, and departures from a Gaussian distribution of these fluctuations. We argue that these signatures are observed experimentally. In chapter 4 we construct an effective theory for the zero mode in this system. This theory is different from the standard Landau-Ginsburg description. It contains gauge fields (the result of the broken translational symmetry inside the cell), which produce observable contributions to the two-point function of the order parameter. We show that the behavior of the two-point function for the network of N genes is described by the action of a relativistic particle moving on the surface of the N - 1 dimensional sphere. We derive a theoretical bound on the decay of the correlations and

  9. Strong dependence of rain-induced lidar depolarization on the illumination angle: experimental evidence and geometrical-optics interpretation.

    PubMed

    Roy, G; Bissonnette, L R

    2001-09-20

    Backscatter and depolarization lidar measurements from clouds and precipitation are reported as functions of the elevation angle of the pointing lidar direction. We recorded the data by scanning the lidar beam (Nd:YAG) at a constant angular speed of ~3.5 degrees /s while operating at a repetition rate of 10 Hz. We show that in rain there is an evident and at times spectacular dependence on the elevation angle. That dependence appears to be sensitive to raindrop size. We have developed a three-dimensional polarization-dependent ray-tracing algorithm to calculate the backscatter and the depolarization ratio by large nonspherical droplets. We have applied it to raindrop shapes derived from existing static and dynamic (oscillating) models. We show that many of the observed complex backscatter and depolarization features can be interpreted to a good extent by geometrical optics. These results suggest that there is a definite need for more extensive calculations of the scattering phase matrix elements for large deformed raindrops as functions of the direction of illumination. Obvious applications are retrieval of information on the liquid-solid phase of precipitation and on the size and the vibration state of raindrops.

  10. Evidence for strong evolution in galaxy environmental quenching efficiency between z = 1.6 and z = 0.9

    NASA Astrophysics Data System (ADS)

    Nantais, Julie B.; Muzzin, Adam; van der Burg, Remco F. J.; Wilson, Gillian; Lidman, Chris; Foltz, Ryan; DeGroot, Andrew; Noble, Allison; Cooper, Michael C.; Demarco, Ricardo

    2017-02-01

    We analyse the evolution of environmental quenching efficiency, the fraction of quenched cluster galaxies which would be star forming if they were in the field, as a function of redshift in 14 spectroscopically confirmed galaxy clusters with 0.87 < z < 1.63 from the Spitzer Adaptation of the Red-Sequence Cluster Survey. The clusters are the richest in the survey at each redshift. Passive fractions rise from 42_{-13}^{+10} per cent at z ˜ 1.6 to 80_{-9}^{+12} per cent at z ˜ 1.3 and 88_{-3}^{+4} per cent at z < 1.1, outpacing the change in passive fraction in the field. Environmental quenching efficiency rises dramatically from 16_{-19}^{+15} per cent at z ˜ 1.6 to 62_{-15}^{+21} per cent at z ˜ 1.3 and 73_{-7}^{+8} per cent at z ≲ 1.1. This work is the first to show direct observational evidence for a rapid increase in the strength of environmental quenching in galaxy clusters at z ˜ 1.5, where simulations show cluster-mass haloes undergo non-linear collapse and virialization.

  11. A strongly interacting polaritonic quantum dot

    NASA Astrophysics Data System (ADS)

    Jia, Ningyuan; Schine, Nathan; Georgakopoulos, Alexandros; Ryou, Albert; Clark, Logan W.; Sommer, Ariel; Simon, Jonathan

    2018-06-01

    Polaritons are promising constituents of both synthetic quantum matter1 and quantum information processors2, whose properties emerge from their components: from light, polaritons draw fast dynamics and ease of transport; from matter, they inherit the ability to collide with one another. Cavity polaritons are particularly promising as they may be confined and subjected to synthetic magnetic fields controlled by cavity geometry3, and furthermore they benefit from increased robustness due to the cavity enhancement in light-matter coupling. Nonetheless, until now, cavity polaritons have operated only in a weakly interacting mean-field regime4,5. Here we demonstrate strong interactions between individual cavity polaritons enabled by employing highly excited Rydberg atoms as the matter component of the polaritons. We assemble a quantum dot composed of approximately 150 strongly interacting Rydberg-dressed 87Rb atoms in a cavity, and observe blockaded transport of photons through it. We further observe coherent photon tunnelling oscillations, demonstrating that the dot is zero-dimensional. This work establishes the cavity Rydberg polariton as a candidate qubit in a photonic information processor and, by employing multiple resonator modes as the spatial degrees of freedom of a photonic particle, the primary ingredient to form photonic quantum matter6.

  12. Suzaku Observation of Strong Fluorescent Iron Line Emission from the Young Stellar Object V1647 Ori during Its New X-ray Outburst

    NASA Technical Reports Server (NTRS)

    Hamaguchi, Kenji; Grosso, Nicolas; Kastner, Joel H.; Weintraub, David A.; Richmond, Michael

    2009-01-01

    The Suzaku X-ray satellite observed the young stellar object V1647 Ori on 2008 October 8 during the new mass accretion outburst reported in August 2008. During the 87 ksec observation with a net exposure of 40 ks, V1647 Ori showed a. high level of X-ray emission with a gradual decrease in flux by a factor of 5 and then displayed an abrupt flux increase by an order of magnitude. Such enhanced X-ray variability was also seen in XMM-Newton observations in 2004 and 2005 during the 2003-2005 outburst, but has rarely been observed for other young stellar objects. The spectrum clearly displays emission from Helium-like iron, which is a signature of hot plasma (kT approx.5 keV). It also shows a fluorescent iron Ka line with a remarkably large equivalent width of approx. 600 eV. Such a, large equivalent width indicates that a part of the incident X-ray emission that irradiates the circumstellar material and/or the stellar surface is hidden from our line of sight. XMM-Newton spectra during the 2003-2005 outburst did not show a strong fluorescent iron Ka line ; so that the structure of the circumstellar gas very close to the stellar core that absorbs and re-emits X-ray emission from the central object may have changed in between 2005 and 2008. This phenomenon may be related to changes in the infrared morphology of McNeil's nebula between 2004 and 2008.

  13. Observations of a Two-Stage Solar Eruptive Event (SEE): Evidence for Secondary Heating

    NASA Technical Reports Server (NTRS)

    Su, Yang; Dennis, Brian R.; Holman, Gordon D.; Wang, Tongjiang; Chamberlin, Phillip C.; Savage, Sabrina; Veronig, Astrid

    2012-01-01

    We present RHESSI, SDO/AIA, SOHO/LASCO, STEREO, and GOES observations of a partially occulted solar eruptive event (SEE) that occurred at the South-West limb on 8 March, 2011. The GOES X-ray light curve shows two peaks separated by almost two hours that we interpret as two stages of a single event associated with the delayed eruption of a CME. A hot flux rope formed during the first stage and continued expanding and rising throughout the event. The speed of the flux rope decreased from approx.120 to 14 km/s during the decay phase of the first stage and increased again during the second stage to become the CME with a speed of approx.516 km/s. RHESSI and GOES data analyses show that the plasma temperature reached over 20 MK in the first stage, then decreased to approx.10 MK and increased to 15 MK in the second stage. This event provides clear evidence for a secondary heating phase. The enhanced EUV and X-ray emission came from the high corona ( approx.60 arcsec above the limb) in the second stage, approx.40 arcsec higher than the site of the initial flare emission. STEREO-A on-disk observations indicate that the post-flare loops during this stage were of larger scale sizes and spatially distinct from those in the first stage.

  14. SDSS-IV MaNGA: the spectroscopic discovery of strongly lensed galaxies

    NASA Astrophysics Data System (ADS)

    Talbot, Michael S.; Brownstein, Joel R.; Bolton, Adam S.; Bundy, Kevin; Andrews, Brett H.; Cherinka, Brian; Collett, Thomas E.; More, Anupreeta; More, Surhud; Sonnenfeld, Alessandro; Vegetti, Simona; Wake, David A.; Weijmans, Anne-Marie; Westfall, Kyle B.

    2018-06-01

    We present a catalogue of 38 spectroscopically detected strong galaxy-galaxy gravitational lens candidates identified in the Sloan Digital Sky Survey IV (SDSS-IV). We were able to simulate narrow-band images for eight of them demonstrating evidence of multiple images. Two of our systems are compound lens candidates, each with two background source-planes. One of these compound systems shows clear lensing features in the narrow-band image. Our sample is based on 2812 galaxies observed by the Mapping Nearby Galaxies at APO (MaNGA) integral field unit (IFU). This Spectroscopic Identification of Lensing Objects (SILO) survey extends the methodology of the Sloan Lens ACS Survey (SLACS) and BOSS Emission-Line Survey (BELLS) to lower redshift and multiple IFU spectra. We searched ˜1.5 million spectra, of which 3065 contained multiple high signal-to-noise ratio background emission-lines or a resolved [O II] doublet, that are included in this catalogue. Upon manual inspection, we discovered regions with multiple spectra containing background emission-lines at the same redshift, providing evidence of a common source-plane geometry which was not possible in previous SLACS and BELLS discovery programs. We estimate more than half of our candidates have an Einstein radius ≳ 1.7 arcsec, which is significantly greater than seen in SLACS and BELLS. These larger Einstein radii produce more extended images of the background galaxy increasing the probability that a background emission-line will enter one of the IFU spectroscopic fibres, making detection more likely.

  15. FIRST ULTRAVIOLET REFLECTANCE SPECTRA OF PLUTO AND CHARON BY THE HUBBLE SPACE TELESCOPE COSMIC ORIGINS SPECTROGRAPH: DETECTION OF ABSORPTION FEATURES AND EVIDENCE FOR TEMPORAL CHANGE

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stern, S. A.; Spencer, J. R.; Shinn, A.

    We have observed the mid-UV spectra of both Pluto and its large satellite, Charon, at two rotational epochs using the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) in 2010. These are the first HST/COS measurements of Pluto and Charon. Here we describe the observations and our reduction of them, and present the albedo spectra, average mid-UV albedos, and albedo slopes we derive from these data. These data reveal evidence for a strong absorption feature in the mid-UV spectrum of Pluto; evidence for temporal change in Pluto's spectrum since the 1990s is reported, and indirect evidence for a near-UV spectralmore » absorption on Charon is also reported.« less

  16. Imaging Strong Lateral Heterogeneities with USArray using Body-to-Surface Wave Scattering

    NASA Astrophysics Data System (ADS)

    Yu, C.; Zhan, Z.; Hauksson, E.; Cochran, E. S.

    2017-12-01

    Seismic scattering is commonly observed and results from wave propagation in heterogeneous medium. Yet, deterministic characterization of scatterers remains challenging. In this study, we analyze broadband waveforms recorded by the USArray across the entire conterminous US. With array analysis, we observe strong scattered surface waves following the arrival of teleseismic body waves over several hundreds of kilometers. We use back-projection to locate the body-to-surface scattering sources, and detect strong scatterers both around and within the conterminous US. For the former, strong scattering is associated with pronounced bathymetric relief, such as the Patton Escarpment in the Southern California Continental Borderland. For the latter, scatterers are consistent with sharp lateral heterogeneities, such as near the Yellowstone hotspot and Southern California fault zones. We further model the body-to-surface wave scattering using finite-difference simulations. As an example, in the Southern California Continental Borderland a simplified 2-D bathymetric and crustal model are able to predict the arrival times and amplitudes of major scatterers. The modeling also suggests a relatively low shear wave velocity in the Continental Borderland. These observation of strong body-to-surface wave scattering and waveform modeling not only helps us image sharp heterogeneities but also are useful for assessing seismic hazard, including the calibration and refinement of seismic velocity models used to locate earthquakes and simulate strong ground motions.

  17. A century of ocean warming on Florida Keys coral reefs: historic in situ observations

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Lidz, Barbara H.; Hudson, J. Harold; Anderson, Jeffery S.

    2015-01-01

    There is strong evidence that global climate change over the last several decades has caused shifts in species distributions, species extinctions, and alterations in the functioning of ecosystems. However, because of high variability on short (i.e., diurnal, seasonal, and annual) timescales as well as the recency of a comprehensive instrumental record, it is difficult to detect or provide evidence for long-term, site-specific trends in ocean temperature. Here we analyze five in situ datasets from Florida Keys coral reef habitats, including historic measurements taken by lighthouse keepers, to provide three independent lines of evidence supporting approximately 0.8 °C of warming in sea surface temperature (SST) over the last century. Results indicate that the warming observed in the records between 1878 and 2012 can be fully accounted for by the warming observed in recent decades (from 1975 to 2007), documented using in situ thermographs on a mid-shore patch reef. The magnitude of warming revealed here is similar to that found in other SST datasets from the region and to that observed in global mean surface temperature. The geologic context and significance of recent ocean warming to coral growth and population dynamics are discussed, as is the future prognosis for the Florida reef tract.

  18. Wide energy electron precipitations associated with chorus waves; Initial observations from Arase and ground-based observations

    NASA Astrophysics Data System (ADS)

    Miyoshi, Y.; Kurita, S.; Saito, S.; Shinohara, I.; Kasahara, Y.; Matsuda, S.; Kasaba, Y.; Yagitani, S.; Kojima, H.; Hikishima, M.; Tsuchiya, F.; Kumamoto, A.; Katoh, Y.; Matsuoka, A.; Higashio, N.; Mitani, T.; Takashima, T.; Kasahara, S.; Yokota, S.; Asamura, K.; Kazama, Y.; Wang, S. Y.; Shiokawa, K.; Oyama, S. I.; Ogawa, Y.; Hosokawa, K.; Kataoka, R.; Kero, A.; Hori, T.; Turunen, E. S.; Shoji, M.; Teramoto, M.; Chang, T. F.

    2017-12-01

    The pulsating aurora is caused by intermittent precipitations of a few - 10s keV electrons, and it is expected that the pitch angle scattering by chorus waves at the magnetosphere is a primary process to cause the pulsating aurora. The Arase satellite that was launched in December, 2016 has obtained comprehensive data sets for plasma/particles and fields/waves. In March and April, 2017, a series of campaign observation focused on the chorus-wave particle interactions from conjugate observations from Arase and ground-based observations, and the pulsating aurora as a manifest of chorus-wave particle ineteractions was the important observation subject. During the campaign observations, good conjugate observations were realized between Arase and ground-based observations in Scandinavia. Associated with the pulsating aurora, the EISCAT VHF incoherent scatter radar at Tromso, Norway observed strong ionization in lower ionosphere. During the period, the Arase satellite observed intense chorus waves near the magnetic equator for a few hours, suggesting that strong pitch angle scattering took place. From the conjugate observations from Arase and ground-based observations, we discuss how chorus waves cause strong precipitation of electrons from plasma sheet and radiation belts.

  19. Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tsargorodska, Anna; Cartron, Michaël L.; Vasilev, Cvetelin

    Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed formore » self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules.« less

  20. Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

    DOE PAGES

    Tsargorodska, Anna; Cartron, Michaël L.; Vasilev, Cvetelin; ...

    2016-09-30

    Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed formore » self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules.« less

  1. Will reducing sugar-sweetened beverage consumption reduce obesity? Evidence supporting conjecture is strong, but evidence when testing effect is weak

    PubMed Central

    Kaiser, Kathryn A.; Shikany, James M.; Keating, Karen D.; Allison, David B.

    2014-01-01

    We provide arguments to the debate question and update a previous meta-analysis with recently published studies on effects of sugar-sweetened beverages (SSBs) on body weight/composition indices (BWIs). We abstracted data from randomized controlled trials examining effects of consumption of SSBs on BWIs. Six new studies met these criteria: 1) human trials, 2) 3 weeks duration, 3) random assignment to conditions differing only in consumption of SSBs, and 4) including a BWI outcome. Updated meta-analysis of a total of seven studies that added SSBs to persons’ diets showed dose-dependent increases in weight. Updated meta-analysis of eight studies attempting to reduce SSB consumption showed an equivocal effect on BWIs in all randomized subjects. When limited to subjects overweight at baseline, meta-analysis showed a significant effect of roughly 0.25 standard deviations (more weight loss/less weight gain) relative to controls. Evidence to date is equivocal in showing that decreasing SSB consumption will reduce the prevalence of obesity. Although new evidence suggests that an effect may yet be demonstrable in some populations, the integrated effect size estimate remains very small and of equivocal statistical significance. Problems in this research area and suggestions for future research are highlighted. PMID:23742715

  2. Strong gravitational lensing probes of the particle nature of dark matter

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas A.; Abazajian, Kevork; Benson, Andrew; Bolton, Adam S.; Bullock, James S.; Chen, Jacqueline; Cheng, Edward; Coe, Dan; Congdon, Arthur B.; Dalal, Neal; Diemand, Juerg; Dobke, Benjamin M.; Dobler, Greg; Dore, Olivier; Dutton, Aaron; Ellis, Richard; Fassnacht, Chris D.; Ferguson, Henry; Finkbeiner, Douglas; Gavassi, Raphael; High, Fredrick William; Jeltema, Telsa; Jullo, Eric; Kaplinghat, Manoj; Keeton, Charles R.; Kneib, Jean-Paul; Koopmans, Leon V.E.; Koishiappas, Savvas M.; Kuhlen, Michael; Kusenko, Alexander; Lawrence, Charles R.; Loeb, Avi; Madae, Piero; Marshall, Phil; Metcalf, R. Ben; Natarajan, Priya; Primack, Joel R.; Profumo, Stefano; Seiffert, Michael D.; Simon, Josh; Stern, Daniel; Strigari, Louis; Taylor, James E.; Wayth, Randall; Wambsganss, Joachim; Wechsler, Risa; Zentner, Andrew

    There is a vast menagerie of plausible candidates for the constituents of dark matter, both within and beyond extensions of the Standard Model of particle physics. Each of these candidates may have scattering (and other) cross section properties that are consistent with the dark matter abundance, BBN, and the most scales in the matter power spectrum; but which may have vastly different behavior at sub-galactic "cutoff" scales, below which dark matter density fluctuations are smoothed out. The only way to quantitatively measure the power spectrum behavior at sub-galactic scales at distances beyond the local universe, and indeed over cosmic time, is through probes available in multiply imaged strong gravitational lenses. Gravitational potential perturbations by dark matter substructure encode information in the observed relative magnifications, positions, and time delays in a strong lens. Each of these is sensitive to a different moment of the substructure mass function and to different effective mass ranges of the substructure. The time delay perturbations, in particular, are proving to be largely immune to the degeneracies and systematic uncertainties that have impacted exploitation of strong lenses for such studies. There is great potential for a coordinated theoretical and observational effort to enable a sophisticated exploitation of strong gravitational lenses as direct probes of dark matter properties. This opportunity motivates this white paper, and drives the need for: a) strong support of the theoretical work necessary to understand all astrophysical consequences for different dark matter candidates; and b) tailored observational campaigns, and even a fully dedicated mission, to obtain the requisite data.

  3. Strong coupling-like phenomenon in single metallic nanoparticle embedded in molecular J-aggregates

    NASA Astrophysics Data System (ADS)

    Feng, Xin; Wang, Chen; Ma, Hongjing; Chen, Yuanyuan; Duan, Gaoyan; Zhang, Pengfei; Song, Gang

    2018-02-01

    Strong coupling-like phenomenon between plasmonic cavities and emitters provides a new way to realize the quantum-like effect controlling at microscale/nanoscale. We investigate the strong coupling-like phenomenon in the structure of single metallic nanoparticle embedded in molecular J-aggregates by the classical simulation method and show that the size of the metallic nanoparticle and the oscillator strength of molecular J-aggregates impact the strong coupling-like phenomenon. The strong coupling-like phenomenon is induced by the interactions between two dipoles formed by the metallic nanoparticle and molecular J-aggregates or the interactions between the dipole generated from molecular J-aggregates and the quadrupole generated from the metallic nanoparticle. The strong coupling-like phenomenon appears evidently with the increase in oscillator strength of molecular J-aggregates. The detuning energy linearly decreases with the increase in radius of the metallic nanoparticle. Our structure has potential applications in quantum networks, quantum key distributions and so on.

  4. First observational evidence for the connection between the meteoric activity and occurrence of equatorial counter electrojet

    NASA Astrophysics Data System (ADS)

    Vineeth, C.; Mridula, N.; Muralikrishna, P.; Kumar, K. K.; Pant, T. K.

    2016-09-01

    This paper presents the first direct observational evidence for the possible role of meteoric activity in the generation of the equatorial Counter Electrojets (CEJ), an enigmatic daytime electrodynamical process over the geomagnetic equatorial upper atmosphere. The investigation carried out using the data from Proton Precession Magnetometer and Meteor Wind Radar over a geomagnetic dip equatorial station, Trivandrum (8.5°N, 77°E, 0.5°N dip lat.) in India, revealed that the occurrence of the afternoon CEJ events during a month is directly proportional to the average monthly meteor counts over this location. The observation is found to be very consistent during the considered period of study, i.e the years 2006 and 2007. The study vindicates that the meteor showers play a major role in setting up the background condition conducive for the generation of CEJ by reducing the strength of the upward polarization field.

  5. Strong self-limitation promotes the persistence of rare species.

    PubMed

    Yenni, Glenda; Adler, Peter B; Ernest, S K Morgan

    2012-03-01

    Theory has recognized a combination of niche and neutral processes each contributing, with varying importance, to species coexistence. However, long-term persistence of rare species has been difficult to produce in trait-based models of coexistence that incorporate stochastic dynamics, raising questions about how rare species persist despite such variability. Following recent evidence that rare species may experience significantly different population dynamics than dominant species, we use a plant community model to simulate the effect of disproportionately strong negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the rare competitors, which otherwise succumb quickly to stochastic extinction. The results suggest that the mechanism causing species to be rare in this case is the same mechanism allowing those species to persist.

  6. Ideal gas behavior of a strongly coupled complex (dusty) plasma.

    PubMed

    Oxtoby, Neil P; Griffith, Elias J; Durniak, Céline; Ralph, Jason F; Samsonov, Dmitry

    2013-07-05

    In a laboratory, a two-dimensional complex (dusty) plasma consists of a low-density ionized gas containing a confined suspension of Yukawa-coupled plastic microspheres. For an initial crystal-like form, we report ideal gas behavior in this strongly coupled system during shock-wave experiments. This evidence supports the use of the ideal gas law as the equation of state for soft crystals such as those formed by dusty plasmas.

  7. Highly Resolved Measurements of a Developing Strong Collisional Plasma Shock

    NASA Astrophysics Data System (ADS)

    Rinderknecht, Hans G.; Park, H.-S.; Ross, J. S.; Amendt, P. A.; Higginson, D. P.; Wilks, S. C.; Haberberger, D.; Katz, J.; Froula, D. H.; Hoffman, N. M.; Kagan, G.; Keenan, B. D.; Vold, E. L.

    2018-03-01

    The structure of a strong collisional shock front forming in a plasma is directly probed for the first time in laser-driven gas-jet experiments. Thomson scattering of a 526.5 nm probe beam was used to diagnose temperature and ion velocity distribution in a strong shock (M ˜11 ) propagating through a low-density (ρ ˜0.01 mg /cc ) plasma composed of hydrogen. A forward-streaming population of ions traveling in excess of the shock velocity was observed to heat and slow down on an unmoving, unshocked population of cold protons, until ultimately the populations merge and begin to thermalize. Instabilities are observed during the merging, indicating a uniquely plasma-phase process in shock front formation.

  8. Strong quantum coherence between Fermi liquid Mahan excitons

    DOE PAGES

    Paul, J.; Stevens, C. E.; Liu, C.; ...

    2016-04-14

    In modulation doped quantum wells, the excitons are formed as a result of the interactions of the charged holes with the electrons at the Fermi edge in the conduction band, leading to the so-called “Mahan excitons.” The binding energy of Mahan excitons is expected to be greatly reduced and any quantum coherence destroyed as a result of the screening and electron-electron interactions. Surprisingly, we observe strong quantum coherence between the heavy hole and light hole excitons. Such correlations are revealed by the dominating cross-diagonal peaks in both one-quantum and two-quantum two-dimensional Fourier transform spectra. Theoretical simulations based on the opticalmore » Bloch equations where many-body effects are included phenomenologically reproduce well the experimental spectra. Furthermore, time-dependent density functional theory calculations provide insight into the underlying physics and attribute the observed strong quantum coherence to a significantly reduced screening length and collective excitations of the many-electron system.« less

  9. Strong Quantum Coherence between Fermi Liquid Mahan Excitons

    NASA Astrophysics Data System (ADS)

    Paul, J.; Stevens, C. E.; Liu, C.; Dey, P.; McIntyre, C.; Turkowski, V.; Reno, J. L.; Hilton, D. J.; Karaiskaj, D.

    2016-04-01

    In modulation doped quantum wells, the excitons are formed as a result of the interactions of the charged holes with the electrons at the Fermi edge in the conduction band, leading to the so-called "Mahan excitons." The binding energy of Mahan excitons is expected to be greatly reduced and any quantum coherence destroyed as a result of the screening and electron-electron interactions. Surprisingly, we observe strong quantum coherence between the heavy hole and light hole excitons. Such correlations are revealed by the dominating cross-diagonal peaks in both one-quantum and two-quantum two-dimensional Fourier transform spectra. Theoretical simulations based on the optical Bloch equations where many-body effects are included phenomenologically reproduce well the experimental spectra. Time-dependent density functional theory calculations provide insight into the underlying physics and attribute the observed strong quantum coherence to a significantly reduced screening length and collective excitations of the many-electron system.

  10. Strong Quantum Coherence between Fermi Liquid Mahan Excitons.

    PubMed

    Paul, J; Stevens, C E; Liu, C; Dey, P; McIntyre, C; Turkowski, V; Reno, J L; Hilton, D J; Karaiskaj, D

    2016-04-15

    In modulation doped quantum wells, the excitons are formed as a result of the interactions of the charged holes with the electrons at the Fermi edge in the conduction band, leading to the so-called "Mahan excitons." The binding energy of Mahan excitons is expected to be greatly reduced and any quantum coherence destroyed as a result of the screening and electron-electron interactions. Surprisingly, we observe strong quantum coherence between the heavy hole and light hole excitons. Such correlations are revealed by the dominating cross-diagonal peaks in both one-quantum and two-quantum two-dimensional Fourier transform spectra. Theoretical simulations based on the optical Bloch equations where many-body effects are included phenomenologically reproduce well the experimental spectra. Time-dependent density functional theory calculations provide insight into the underlying physics and attribute the observed strong quantum coherence to a significantly reduced screening length and collective excitations of the many-electron system.

  11. The Endocrine Society guidelines: when the confidence cart goes before the evidence horse.

    PubMed

    Brito, Juan P; Domecq, Juan P; Murad, Mohammed H; Guyatt, Gordon H; Montori, Victor M

    2013-08-01

    In 2005, the Endocrine Society (TES) adopted the GRADE system of developing clinical practice guidelines. Grading of Recommendations, Assessment, Development, and Evaluation working group guidance suggests that strong recommendations based on low or very low (L/VL) confidence may often be inappropriate, and has offered a taxonomy of paradigmatic situations in which strong recommendations based on L/VL confidence estimates may be appropriate. We sought to characterize strong recommendations of TES based on L/VL confidence evidence. We identified all strong recommendations based on L/VL confidence evidence published in TES guidelines between 2005 and 2011. We identified those consistent with one of the paradigmatic situations in the taxonomy. Two hundred six of 357 (58%) of the recommendations of TES were strong; of these, 121 (59%) were based on L/VL confidence evidence. Of these 121, 35 (29%) were consistent with one of the paradigmatic situations. The most common situation (13, 11%) was of a strong recommendation against the intervention because of low confidence evidence for benefit and high confidence evidence for harm. The remaining 86 (71%) comprised 43 (36%) "best practice" statements for which sensible alternatives do not exist; 5 (4%) in which recommendations were for "additional research"; 5 (4%) in which greater confidence in the estimates was warranted; and 33 (27%) for which we could not find a compelling explanation for the incongruence. Guideline panels should beware of formulating strong recommendations when confidence in estimates is low. Our taxonomy when such recommendations are appropriate may be helpful.

  12. Pre-Global Surveyor evidence for Martian ground water

    PubMed Central

    Donahue, Thomas M.

    2001-01-01

    A time-dependent theory for the evolution of water on Mars is presented. Using this theory and invoking a large number of observational constraints, I argue that these constraints require that a large reservoir of water exists in the Martian crust at depths shallow enough to interact strongly with the atmosphere. The constraints include the abundance of atmospheric water vapor, escape fluxes of hydrogen and deuterium, D/H ratios in the atmosphere and in hydrous minerals found in one Martian meteorite, alteration of minerals in other meteorites, and fluvial features on the Martian surface. These results are consonant with visual evidence for recent groundwater seepage obtained by the Mars Global Surveyor satellite. PMID:11158555

  13. Chandra Observations of Magnetic White Dwarfs and their Theoretical Implications

    NASA Technical Reports Server (NTRS)

    Musielak, Z. E.; Noble, M.; Porter, J. G.; Winget, D. E.

    2003-01-01

    Observations of cool DA and DB white dwarfs have not yet been successful in detecting coronal X-ray emission, but observations of late-type dwarfs and giants show that coronae are common for these stars. To produce coronal X-rays, a star must have dynamo-generated surface magnetic fields and a well-developed convection zone. There is some observational evidence that the DA star LHS 1038 and the DB star GD 358 have weak and variable surface magnetic fields. It has been suggested that such fields can be generated by dynamo action, and since both stars have well-developed convection zones, theory predicts detectable levels of coronal X-rays from these white dwarfs. However, we present analysis of Chandra observations of both stars showing no detectable X-ray emission. The derived upper limits for the X-ray fluxes provide strong constraints on theories of formation of coronae around magnetic white dwarfs. Another important implication of our negative Chandra observations is the possibility that the magnetic fields of LHS 1038 and GD 358 are fossil fields.

  14. Plain packaging of cigarettes: do we have sufficient evidence?

    PubMed Central

    Smith, Collin N; Kraemer, John D; Johnson, Andrea C; Mays, Darren

    2015-01-01

    Tobacco industry marketing is a primary factor influencing cigarette smoking behavior and the cigarette pack has become an important marketing vehicle for tobacco companies. Standardized “plain” cigarette packaging is advocated as a public health policy to prevent and reduce morbidity and mortality caused by smoking by reducing youth smoking initiation and promoting cessation among smokers. Plain packaging was implemented in Australia in December 2012, and several other countries are considering doing so, but each faces foreseeable legal resistance from opponents to such measures. Tobacco companies have challenged these public health policies, citing international trade agreements and intellectual property laws. Decision-making in these court cases will hinge in part on whether the evidence indicates the public health benefits of plain packaging outweigh any potential harm to tobacco manufacturers’ interests. We reviewed the available evidence in support of plain packaging, finding evidence from observational, experimental, and population-based studies. Results indicate that plain packaging can reduce positive perceptions of smoking and dissuade tobacco use. Governments deciding to implement plain cigarette packaging measures can rely on this evidence to help make a strong case that plain packaging plays an important role in the context of comprehensive smoking prevention efforts. PMID:25897269

  15. The first detection of neutral hydrogen in emission in a strong spiral lens

    NASA Astrophysics Data System (ADS)

    Lipnicky, Andrew; Chakrabarti, Sukanya; Wright, Melvyn C. H.; Blitz, Leo; Heiles, Carl; Cotton, William; Frayer, David; Blandford, Roger; Shu, Yiping; Bolton, Adam S.

    2018-05-01

    We report H I observations of eight spiral galaxies that are strongly lensing background sources. Our targets were selected from the Sloan WFC (Wide Field Camera) Edge-on Late-type Lens Survey (SWELLS) using the Arecibo, Karl G. Jansky Very Large Array, and Green Bank telescopes. We securely detect J1703+2451 at z = 0.063 with a signal-to-noise ratio of 6.7 and W50 = 79 ± 13 km s-1, obtaining the first detection of H I emission in a strong spiral lens. We measure a mass of M_{H I} = (1.77± 0.06^{+0.35}_{-0.75})× 10^9 M_{⊙} for this source. We find that this lens is a normal spiral, with observable properties that are fairly typical of spiral galaxies. For three other sources, we did not secure a detection; however, we are able to place strong constraints on the H I masses of those galaxies. The observations for four of our sources were rendered unusable due to strong radio frequency interference.

  16. Serum uric acid levels and multiple health outcomes: umbrella review of evidence from observational studies, randomised controlled trials, and Mendelian randomisation studies.

    PubMed

    Li, Xue; Meng, Xiangrui; Timofeeva, Maria; Tzoulaki, Ioanna; Tsilidis, Konstantinos K; Ioannidis, John PA; Campbell, Harry; Theodoratou, Evropi

    2017-06-07

    Objective  To map the diverse health outcomes associated with serum uric acid (SUA) levels. Design  Umbrella review. Data sources  Medline, Embase, Cochrane Database of Systematic Reviews, and screening of citations and references. Eligibility criteria  Systematic reviews and meta-analyses of observational studies that examined associations between SUA level and health outcomes, meta-analyses of randomised controlled trials that investigated health outcomes related to SUA lowering treatment, and Mendelian randomisation studies that explored the causal associations of SUA level with health outcomes. Results  57 articles reporting 15 systematic reviews and144 meta-analyses of observational studies (76 unique outcomes), 8 articles reporting 31 meta-analyses of randomised controlled trials (20 unique outcomes), and 36 articles reporting 107 Mendelian randomisation studies (56 unique outcomes) met the eligibility criteria. Across all three study types, 136 unique health outcomes were reported. 16 unique outcomes in meta-analyses of observational studies had P<10 -6 , 8 unique outcomes in meta-analyses of randomised controlled trials had P<0.001, and 4 unique outcomes in Mendelian randomisation studies had P<0.01. Large between study heterogeneity was common (80% and 45% in meta-analyses of observational studies and of randomised controlled trials, respectively). 42 (55%) meta-analyses of observational studies and 7 (35%) meta-analyses of randomised controlled trials showed evidence of small study effects or excess significance bias. No associations from meta-analyses of observational studies were classified as convincing; five associations were classified as highly suggestive (increased risk of heart failure, hypertension, impaired fasting glucose or diabetes, chronic kidney disease, coronary heart disease mortality with high SUA levels). Only one outcome from randomised controlled trials (decreased risk of nephrolithiasis recurrence with SUA lowering treatment

  17. Strong Evidence against a Non-degenerate Companion in SN 2012cg

    NASA Astrophysics Data System (ADS)

    Shappee, B. J.; Piro, A. L.; Stanek, K. Z.; Patel, S. G.; Margutti, R. A.; Lipunov, V. M.; Pogge, R. W.

    2018-03-01

    Even though SN 2012cg is one of the best-studied Type Ia supernovae to date, the nature of its progenitor system has been debated in numerous studies. Specifically, it is difficult to reconcile recent claims of the detection of a ∼6 {M}ȯ MS companion with recent deep, late-time {{H}}α flux limits. In this study we add three new constraints. (1) We analyze a new high-signal-to-noise, nebular-phase, Large Binocular Telescope/MODS spectrum of SN 2012cg and place an upper limit on the amount of low-velocity, solar-abundance material removed from a possible companion of < 7.8× {10}-3 {M}ȯ . (2) We use Swift X-ray observations to constrain the pre-explosion mass-loss rate to be \\dot{M}< {10}-6 {M}ȯ {yr}}-1 for {v}{{w}}=100 {km} {{{s}}}-1. (3) We carefully reanalyze a prediscovery MASTER image, and with published light curves of SN 2012cg we estimate the time of first light and conservatively constrain the radius of a Roche-lobe overflowing companion to be < 0.24 {R}ȯ . These observations disagree with a large nearby companion, and when considered with other studies of SN 2012cg’s progenitor system, essentially rule out a non-degenerate companion.

  18. Starting off on the right foot: strong right-footers respond faster with the right foot to positive words and with the left foot to negative words

    PubMed Central

    de la Vega, Irmgard; Graebe, Julia; Härtner, Leonie; Dudschig, Carolin; Kaup, Barbara

    2015-01-01

    Recent studies have provided evidence for an association between valence and left/right modulated by handedness, which is predicted by the body-specificity hypothesis (Casasanto, 2009) and also reflected in response times. We investigated whether such a response facilitation can also be observed with foot responses. Right-footed participants classified positive and negative words according to their valence by pressing a key with their left or right foot. A significant interaction between valence and foot only emerged in the by-items analysis. However, when dividing participants into two groups depending on the strength of their footedness, an interaction between valence and left/right was observed for strong right-footers, who responded faster with the right foot to positive words, and with the left foot to negative words. No interaction emerged for weak right-footers. The results strongly support the assumption that fluency lies at the core of the association between valence and left/right. PMID:25852609

  19. Observational insights into aerosol formation from isoprene.

    PubMed

    Worton, David R; Surratt, Jason D; Lafranchi, Brian W; Chan, Arthur W H; Zhao, Yunliang; Weber, Robin J; Park, Jeong-Hoo; Gilman, Jessica B; de Gouw, Joost; Park, Changhyoun; Schade, Gunnar; Beaver, Melinda; Clair, Jason M St; Crounse, John; Wennberg, Paul; Wolfe, Glenn M; Harrold, Sara; Thornton, Joel A; Farmer, Delphine K; Docherty, Kenneth S; Cubison, Michael J; Jimenez, Jose-Luis; Frossard, Amanda A; Russell, Lynn M; Kristensen, Kasper; Glasius, Marianne; Mao, Jingqiu; Ren, Xinrong; Brune, William; Browne, Eleanor C; Pusede, Sally E; Cohen, Ronald C; Seinfeld, John H; Goldstein, Allen H

    2013-10-15

    Atmospheric photooxidation of isoprene is an important source of secondary organic aerosol (SOA) and there is increasing evidence that anthropogenic oxidant emissions can enhance this SOA formation. In this work, we use ambient observations of organosulfates formed from isoprene epoxydiols (IEPOX) and methacrylic acid epoxide (MAE) and a broad suite of chemical measurements to investigate the relative importance of nitrogen oxide (NO/NO2) and hydroperoxyl (HO2) SOA formation pathways from isoprene at a forested site in California. In contrast to IEPOX, the calculated production rate of MAE was observed to be independent of temperature. This is the result of the very fast thermolysis of MPAN at high temperatures that affects the distribution of the MPAN reservoir (MPAN / MPA radical) reducing the fraction that can react with OH to form MAE and subsequently SOA (F(MAE formation)). The strong temperature dependence of F(MAE formation) helps to explain our observations of similar concentrations of IEPOX-derived organosulfates (IEPOX-OS; ~1 ng m(-3)) and MAE-derived organosulfates (MAE-OS; ~1 ng m(-3)) under cooler conditions (lower isoprene concentrations) and much higher IEPOX-OS (~20 ng m(-3)) relative to MAE-OS (<0.0005 ng m(-3)) at higher temperatures (higher isoprene concentrations). A kinetic model of IEPOX and MAE loss showed that MAE forms 10-100 times more ring-opening products than IEPOX and that both are strongly dependent on aerosol water content when aerosol pH is constant. However, the higher fraction of MAE ring opening products does not compensate for the lower MAE production under warmer conditions (higher isoprene concentrations) resulting in lower formation of MAE-derived products relative to IEPOX at the surface. In regions of high NOx, high isoprene emissions and strong vertical mixing the slower MPAN thermolysis rate aloft could increase the fraction of MPAN that forms MAE resulting in a vertically varying isoprene SOA source.

  20. The Practice of Using Evidence in Kindergarten: The Role of Purposeful Observation

    ERIC Educational Resources Information Center

    Monteira, Sabela F.; Jiménez-Aleixandre, María Pilar

    2016-01-01

    This article examines kindergarten children's (5-6 years old) engagement in scientific practices, with a focus on generating and using evidence to support claims, during a 5-month project about snails. The research questions are as follows: (1) what meanings do kindergarteners construct for what constitutes evidence? How are those meanings…

  1. Evidence for -Gz Adaptation Observed with Wearable Biosensors During High Performance Jet Flight.

    PubMed

    Rice, G Merrill; Snider, Dallas; Moore, Jeffrey L; Lavan, J Timothy; Folga, Rich; VanBrunt, Thomas B

    2016-12-01

    Few studies have evaluated physiological responses to high acceleration forces during actual flight and to our knowledge no normative data has been acquired by technologies such as wearable biosensors during high performance jet aircraft operations. In-flight physiological data from an FDA cleared portable triaxial accelerometer and bio-sensor were observed from five active duty F-18 pilots of the Naval Flight Demonstration Squadron (Blue Angels). Of the five pilots, three were formation pilots who flew lower G profiles and two were solo pilots who flew higher G profiles. Physiological parameters monitored were heart rate, respiratory rate, temperature, caloric expenditure, and duration of exposure to levels of acceleration. Evaluated were 25 practice demonstration flights; 9 flights were excluded secondary to incomplete or inaccurate physiological data. We observed no significant bradycardia during a total of 189 maneuvers which met inclusion criteria for push-pull events (PPE) or isolated -Gz exposures. Further analysis of 73 PPE revealed an overall significant rise in HR following the PPE, where mean heart rate was 106 (95% CI, 100:112) at the beginning of the push and 129 (95% CI, 123:135) following the pull. A majority of the flights monitored provided reliable physiological data. Initial data suggests, contrary to currently held aeromedical doctrine, maneuvers such as the "push-pull" do not evoke vasovagal based bradycardic responses in aerobatic pilots. Possible explanations for these findings are sympathetic nervous system activation through adaptation and/or sustained isometric resistance from control inputs, both of which are areas of future research for our team.Rice GM, Snider D, Moore JL, Lavan JT, Folga R, VanBrunt TB. Evidence for -Gz adaptation observed with wearable biosensors during high performance jet flight. Aerosp Med Hum Perform. 2016; 87(12):996-1003.

  2. A note on the observational evidence for the existence of event horizons in astrophysical black hole candidates.

    PubMed

    Bambi, Cosimo

    2013-01-01

    Black holes have the peculiar and intriguing property of having an event horizon, a one-way membrane causally separating their internal region from the rest of the Universe. Today, astrophysical observations provide some evidence for the existence of event horizons in astrophysical black hole candidates. In this short paper, I compare the constraint we can infer from the nonobservation of electromagnetic radiation from the putative surface of these objects with the bound coming from the ergoregion instability, pointing out the respective assumptions and limitations.

  3. Einstein observations of the X-ray structure of Centaurus A - Evidence for the radio-lobe energy source

    NASA Technical Reports Server (NTRS)

    Schreier, E. J.; Feigelson, E.; Delvaille, J.; Giacconi, R.; Grindlay, J.; Schwartz, D. A.; Fabian, A. C.

    1979-01-01

    The X-ray source at the center of the radio galaxy Centaurus A has been resolved into the following components with the imaging detectors on board the Einstein X-ray Observatory: (1) a point source coincident with the infrared nucleus; (2) diffuse X-ray emission coinciding with the inner radio lobes; (3) a 4-arcmin extended region of emission about the nucleus; and (4) an X-ray jet between the nucleus and the NE inner radio lobe. The 2 x 10 to the 39th ergs/s detected from the radio lobes probably arises from inverse Compton scattering of the microwave background. The average magnetic field in the SW lobe is determined to be not less than 4 microgauss. The extended region may be due to emission by a cloud of hot gas, cosmic-ray scattering, or stellar sources. The jet provides strong evidence for the continuous resupply of energy to the lobes from the nucleus.

  4. Tigers in the Terai: Strong evidence for meta-population dynamics contributing to tiger recovery and conservation in the Terai Arc Landscape.

    PubMed

    Thapa, Kanchan; Wikramanayake, Eric; Malla, Sabita; Acharya, Krishna Prasad; Lamichhane, Babu Ram; Subedi, Naresh; Pokharel, Chiranjivi Prasad; Thapa, Gokarna Jung; Dhakal, Maheshwar; Bista, Ashish; Borah, Jimmy; Gupta, Mudit; Maurya, Kamlesh K; Gurung, Ghana Shyam; Jnawali, Shant Raj; Pradhan, Narendra Man Babu; Bhata, Shiv Raj; Koirala, Saroj; Ghose, Dipankar; Vattakaven, Joseph

    2017-01-01

    The source populations of tigers are mostly confined to protected areas, which are now becoming isolated. A landscape scale conservation strategy should strive to facilitate dispersal and survival of dispersing tigers by managing habitat corridors that enable tigers to traverse the matrix with minimal conflict. We present evidence for tiger dispersal along transboundary protected areas complexes in the Terai Arc Landscape, a priority tiger landscape in Nepal and India, by comparing camera trap data, and through population models applied to the long term camera trap data sets. The former showed that 11 individual tigers used the corridors that connected the transboundary protected areas. The estimated population growth rates using the minimum observed population size in two protected areas in Nepal, Bardia National Park and Suklaphanta National Park showed that the increases were higher than expected from growth rates due to in situ reproduction alone. These lines of evidence suggests that tigers are recolonizing Nepal's protected areas from India, after a period of population decline, and that the tiger populations in the transboundary protected areas complexes may be maintained as meta-population. Our results demonstrate the importance of adopting a landscape-scale approach to tiger conservation, especially to improve population recovery and long term population persistence.

  5. Tigers in the Terai: Strong evidence for meta-population dynamics contributing to tiger recovery and conservation in the Terai Arc Landscape

    PubMed Central

    Wikramanayake, Eric; Malla, Sabita; Acharya, Krishna Prasad; Lamichhane, Babu Ram; Subedi, Naresh; Pokharel, Chiranjivi Prasad; Thapa, Gokarna Jung; Dhakal, Maheshwar; Bista, Ashish; Borah, Jimmy; Gupta, Mudit; Maurya, Kamlesh K.; Gurung, Ghana Shyam; Jnawali, Shant Raj; Pradhan, Narendra Man Babu; Bhata, Shiv Raj; Koirala, Saroj; Ghose, Dipankar; Vattakaven, Joseph

    2017-01-01

    The source populations of tigers are mostly confined to protected areas, which are now becoming isolated. A landscape scale conservation strategy should strive to facilitate dispersal and survival of dispersing tigers by managing habitat corridors that enable tigers to traverse the matrix with minimal conflict. We present evidence for tiger dispersal along transboundary protected areas complexes in the Terai Arc Landscape, a priority tiger landscape in Nepal and India, by comparing camera trap data, and through population models applied to the long term camera trap data sets. The former showed that 11 individual tigers used the corridors that connected the transboundary protected areas. The estimated population growth rates using the minimum observed population size in two protected areas in Nepal, Bardia National Park and Suklaphanta National Park showed that the increases were higher than expected from growth rates due to in situ reproduction alone. These lines of evidence suggests that tigers are recolonizing Nepal’s protected areas from India, after a period of population decline, and that the tiger populations in the transboundary protected areas complexes may be maintained as meta-population. Our results demonstrate the importance of adopting a landscape-scale approach to tiger conservation, especially to improve population recovery and long term population persistence. PMID:28591175

  6. Strong cation exchange-type chiral stationary phase for enantioseparation of chiral amines in subcritical fluid chromatography.

    PubMed

    Wolrab, Denise; Kohout, Michal; Boras, Mario; Lindner, Wolfgang

    2013-05-10

    A new strong cation exchange type chiral stationary phase (SCX CSP) based on a syringic acid amide derivative of trans-(R, R)-2-aminocyclohexanesulfonic acid was applied to subcritical fluid chromatography (SFC) for separation of various chiral basic drugs and their analogues. Mobile phase systems consisting of aliphatic alcohols as polar modifiers and a broad range of amines with different substitution patterns and lipophilicity were employed to evaluate the impact on the SFC retention and selectivity characteristics. The observed results point to the existence of carbonic and carbamic acid salts formed as a consequence of reactions occurring between carbon dioxide, the alcoholic modifiers and the amine species present in the sub/supercritical fluid medium, respectively. Evidence is provided that these species are essential for affecting ion exchange between the strongly acidic chiral selector units and the basic analytes, following the well-established stoichiometric displacement mechanisms. Specific trends were observed when different types of amines were used as basic additives. While ammonia gave rise to the formation of the most strongly eluting carbonic and carbamic salt species, simple tertiary amines consistently provided superior levels of enantioselectivity. Furthermore, trends in the chiral SFC separation characteristics were investigated by the systematic variation of the modifier content and temperature. Different effects of additives are interpreted in terms of changes in the relative concentration of the transient ionic species contributing to analyte elution, with ammonia-derived carbamic salts being depleted at elevated temperatures by decomposition. Additionally, in an effort to optimize SFC enantiomer separation conditions for selected analytes, the impact of the type of the organic modifier, temperature, flow rate and active back pressure were also investigated. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Global QBO in circulation and ozone. Part 1: Reexamination of observational evidence

    NASA Technical Reports Server (NTRS)

    Tung, K. K.; Yang, H.

    1994-01-01

    Observational evidence for a global quasi-biennial oscillation (QBO) pattern is reviewed. In particular, the presence of an extratropical, as well as an equatorial, component of the QBO signal in column ozone is established. It is found that the ozone interannual variability is such that as one moves away from the Tropics, the frequency spectrum of the anomaly changes from one that is dominated by the equatorial QBO frequency of 1/30 mo to a two-peak spectrum around the two frequencies: 1/30 mo and 1/20 mo. Instead of treating the 1/20 mo frequency as a separate phenomenon to be filtered away in extracting the QBO in the extratropics, as was previously done, the authors argue that both peaks are integral parts of the extratropical QBO phenomenon. The 1/20 mo frequency happens to be the difference combination of the QBO frequency 1/30 mo and the annual frequency 1/12 mo. Therefore, it can represent the result of the QBO modulating an annual cycle. The authors suggest that previous methods of extracting the extratropical QBO signal severely underestimated the contribution of the QBO to the interannual variability of ozone when data are filtered to pass only the component with the period of equatorial QBO. Further, it is argued that the transport of equatorial QBO ozone anomaly by a non-QBO circulation can at most account for 6-8 Dobson units (DU) of the observed interannual variability of column ozone in the extratropics. The remaining variability (up to 20 DU) probably cannot be produced without an anomaly in the transporting circulation in the extratropics.

  8. Global QBO in circulation and ozone. Part 1: Reexamination of observational evidence

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tung, K.K.; Yang, H.

    1994-10-01

    Observational evidence for a global quasi-biennial oscillation (QBO) pattern is reviewed. In particular, the presence of an extratropical, as well as an equatorial, component of the QBO signal in column ozone is established. It is found that the ozone interannual variability is such that as one moves away from the Tropics, the frequency spectrum of the anomaly changes from one that is dominated by the equatorial QBO frequency of 1/30 mo to a two-peak spectrum around the two frequencies: 1/30 mo and 1/20 mo. Instead of treating the 1/20 mo frequency as a separate phenomenon to be filtered away inmore » extracting the QBO in the extratropics, as was previously done, the authors argue that both peaks are integral parts of the extratropical QBO phenomenon. The 1/20 mo frequency happens to be the difference combination of the QBO frequency 1/30 mo and the annual frequency 1/12 mo. Therefore, it can represent the result of the QBO modulating an annual cycle. The authors suggest that previous methods of extracting the extratropical QBO signal severely underestimated the contribution of the QBO to the interannual variability of ozone when data are filtered to pass only the component with the period of equatorial QBO. Further, it is argued that the transport of equatorial QBO ozone anomaly by a non-QBO circulation can at most account for 6-8 Dobson units (DU) of the observed interannual variability of column ozone in the extratropics. The remaining variability (up to 20 DU) probably cannot be produced without an anomaly in the transporting circulation in the extratropics.« less

  9. Spectral Index and Quasi-Periodic Oscillation Frequency Correlation in Black Hole (BH) Sources: Observational Evidence of Two Phases and Phase Transition in BHs

    NASA Technical Reports Server (NTRS)

    Titarchuk, Lev; Fiorito, Ralph

    2004-01-01

    Recent studies have shown that strong correlations are observed between the low frequencies (1-10 Hz) of quasiperiodic oscillations (QPOs) and the spectral power law index of several Black Hole (BH) candidate sources, in low hard states, steep power-law (soft) states and in transition between these states. The observations indicate that the X-ray spectrum of such state (phases) show the presence of a power-law component and are sometimes related to simultaneous radio emission indicated the probable presence of a jet. Strong QPOs (less than 20% rms) are present in the power density spectrum in the spectral range where the power-law component is dominant ( i.e. 60-90% ). This evidence contradicts the dominant long standing interpretation of QPOs as a signature of the thermal accretion disk. We present the data from the literature and our own data to illustrate the dominance of power-law index-QPO frequency correlations. We provide a model, that identifies and explains the origin of the QPOs and how they are imprinted on the properties of power-law flux component. We argue the existence of a bounded compact coronal region which is a natural consequence of the adjustment of Keplerian disk flow to the innermost sub-Keplerian boundary conditions near the central object and that ultimately leads to the formation of a transition layer (TL) between the adjustment radius and the innermost boundary. The model predicts two phases or states dictated by the photon upscattering produced in the TL: (1) hard state, in which the TL is optically thin and very hot (kT approx. greater than 50 keV) producing photon upscattering via thermal Componization; the photon spectrum index Gamma appprox.1.5 for this state is dictated by gravitational energy release and Compton cooling in an optically thin shock near the adjustment radius; (2) a soft state which is optically thick and relatively cold (approx. less than 5 keV); the index for this state, Gamma approx. 2.8 is determined by soft

  10. Spectral Index and Quasi-Periodic Oscillation Frequency Correlation in Black Hole Sources: Observational Evidence of Two Phases and Phase Transition in Black Holes

    NASA Technical Reports Server (NTRS)

    Titarchuk, Lev; Fiorito, Ralph

    2004-01-01

    Recent studies have shown that strong correlations are observed between the low frequencies (1-10 Hz) of quasi-periodic oscillations (QPOs) and the spectral power law index of several black hole (BH) candidate sources, in low (hard) states, steep power law (soft) states, and transitions between these states. The observations indicate that the X-ray spectra of such state (phases) show the presence of a power-law component and are sometimes related to simultaneous radio emission, indicating the probable presence of a jet. Strong QPOs (>20% rms) are present in the power density spectrum in the spectral range where the power-law component is dominant (i.e., 60%90%). This evidence contradicts the dominant, long-standing interpretation of QPOs as a signature of the thermal accretion disk. We present the data from the literature and our own data to illustrate the dominance of power-law index-QPO frequency correlations. We provide a model that identifies and explains the origin of the QPOs and how they are imprinted on the properties of the power-law flux component. We argue for the existence of a bounded compact coronal region that is a natural consequence of the adjustment of the Keplerian disk flow to the innermost sub-Keplerian boundary conditions near the central object and that ultimately leads to the formation of a transition layer (TL) between the adjustment radius and the innermost boundary. The model predicts two phases or states dictated by the photon upscattering produced in the TL: (1) a hard state, in which the TL is optically thin and very hot (kT approximately greater than 50 keV), producing photon upscattering via thermal Comptonization (the photon spectrum index Gamma approximates 1.7 for this state is dictated by gravitational energy release and Compton cooling in an optically thin shock near the adjustment radius), and (2) a soft state that is optically thick and relatively cold (kT approximately less than 5 keV the index for this state, Gamma

  11. Long memory volatility of gold price returns: How strong is the evidence from distinct economic cycles?

    NASA Astrophysics Data System (ADS)

    Bentes, Sonia R.

    2016-02-01

    This paper examines the long memory behavior in the volatility of gold returns using daily data for the period 1985-2009. We divided the whole sample into eight sub-samples in order to analyze the robustness and consistency of our results during different crisis periods. This constitutes our main contribution. We cover four major world crises, namely, (i) the US stock market crash of 1987; (ii) the Asian financial crisis of 1997; (iii) the World Trade Center terrorist attack of 2001 and finally, (iv) the sub-prime crisis of 2007, in order to investigate how the fractional integrated parameter of the FIGARCH(1, d,1) model evolves over time. Our findings are twofold: (i) there is evidence of long memory in the conditional variance over the whole sample period; (ii) when we consider the sub-sample analysis, the results show mixed evidence. Thus, for the 1985-2003 period the long memory parameter is positive and statistically significant in the pre-crisis sub-samples, and there is no evidence of long memory in the crisis sub-sample periods; however the reverse pattern occurs for the 2005-2009 period. This highlights the unique characteristics of the 2007 sub-prime crisis.

  12. Emerging Signs of Strong Reciprocity in Human Ontogeny

    PubMed Central

    Robbins, Erin; Rochat, Philippe

    2011-01-01

    Strong reciprocity is considered here as the propensity to sacrifice resources to be kind or to punish in response to prior acts, a behavior not simply reducible to self-interest and a likely force behind human cooperation and sociality. The aim was to capture emerging signs of strong reciprocity in human ontogeny and across highly contrasted cultures. Three- and 5-year-old middle class American children (N = 162) were tested in a simple, multiple round, three-way sharing game involving the child, a generous puppet, and a stingy puppet. At the end of the game, the child was offered an opportunity to sacrifice some of her personal gains to punish one of the puppets. By 3 years, American children demonstrate a willingness to engage in costly punishment. However, only 5-year-olds show some evidence of strong reciprocity by orienting their punishment systematically toward the stingy puppet. Further analyses and three additional control conditions demonstrate that such propensity is not simply reducible to (a) straight imitation, or (b) inequity aversion. To assess the relative universality of such development, a group of 5- to 6-year-old children from rural Samoa (N = 14) were tested and compared to age and gender-matched American children. Samoan children did not manifest the same propensity toward strong reciprocity. The results are interpreted as pointing to (1) the developmental emergence of an ethical stance between 3 and 5 years of age, and (2) that the expression of such stance by young children could depend on culture. PMID:22194730

  13. Estimating population ecology models for the WWW market: evidence of competitive oligopolies.

    PubMed

    de Cabo, Ruth Mateos; Gimeno, Ricardo

    2013-01-01

    This paper proposes adapting a particle filtering algorithm to model online Spanish real estate and job search market segments based on the Lotka-Volterra competition equations. For this purpose the authors use data on Internet information searches from Google Trends to proxy for market share. Market share evolution estimations are coherent with those observed in Google Trends. The results show evidence of low website incompatibility in the markets analyzed. Competitive oligopolies are most common in such low-competition markets, instead of the monopolies predicted by theoretical ecology models under strong competition conditions.

  14. PORTAAL: A Classroom Observation Tool Assessing Evidence-Based Teaching Practices for Active Learning in Large Science, Technology, Engineering, and Mathematics Classes

    PubMed Central

    Eddy, Sarah L.; Converse, Mercedes; Wenderoth, Mary Pat

    2015-01-01

    There is extensive evidence that active learning works better than a completely passive lecture. Despite this evidence, adoption of these evidence-based teaching practices remains low. In this paper, we offer one tool to help faculty members implement active learning. This tool identifies 21 readily implemented elements that have been shown to increase student outcomes related to achievement, logic development, or other relevant learning goals with college-age students. Thus, this tool both clarifies the research-supported elements of best practices for instructor implementation of active learning in the classroom setting and measures instructors’ alignment with these practices. We describe how we reviewed the discipline-based education research literature to identify best practices in active learning for adult learners in the classroom and used these results to develop an observation tool (Practical Observation Rubric To Assess Active Learning, or PORTAAL) that documents the extent to which instructors incorporate these practices into their classrooms. We then use PORTAAL to explore the classroom practices of 25 introductory biology instructors who employ some form of active learning. Overall, PORTAAL documents how well aligned classrooms are with research-supported best practices for active learning and provides specific feedback and guidance to instructors to allow them to identify what they do well and what could be improved. PMID:26033871

  15. Arsenic metabolism and one-carbon metabolism at low-moderate arsenic exposure: Evidence from the Strong Heart Study.

    PubMed

    Spratlen, Miranda Jones; Gamble, Mary V; Grau-Perez, Maria; Kuo, Chin-Chi; Best, Lyle G; Yracheta, Joseph; Francesconi, Kevin; Goessler, Walter; Mossavar-Rahmani, Yasmin; Hall, Meghan; Umans, Jason G; Fretts, Amanda; Navas-Acien, Ana

    2017-07-01

    B-vitamins involved in one-carbon metabolism (OCM) can affect arsenic metabolism efficiency in highly arsenic exposed, undernourished populations. We evaluated whether dietary intake of OCM nutrients (including vitamins B2, B6, folate (B9), and B12) was associated with arsenic metabolism in a more nourished population exposed to lower arsenic than previously studied. Dietary intake of OCM nutrients and urine arsenic was evaluated in 405 participants from the Strong Heart Study. Arsenic exposure was measured as the sum of iAs, monomethylarsonate (MMA) and dimethylarsenate (DMA) in urine. Arsenic metabolism was measured as the individual percentages of each metabolite over their sum (iAs%, MMA%, DMA%). In adjusted models, increasing intake of vitamins B2 and B6 was associated with modest but significant decreases in iAs% and MMA% and increases in DMA%. A significant interaction was found between high folate and B6 with enhanced arsenic metabolism efficiency. Our findings suggest OCM nutrients may influence arsenic metabolism in populations with moderate arsenic exposure. Stronger and independent associations were observed with B2 and B6, vitamins previously understudied in relation to arsenic. Research is needed to evaluate whether targeting B-vitamin intake can serve as a strategy for the prevention of arsenic-related health effects at low-moderate arsenic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Asteroseismology can reveal strong internal magnetic fields in red giant stars.

    PubMed

    Fuller, Jim; Cantiello, Matteo; Stello, Dennis; Garcia, Rafael A; Bildsten, Lars

    2015-10-23

    Internal stellar magnetic fields are inaccessible to direct observations, and little is known about their amplitude, geometry, and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields can manifest themselves via depressed dipole stellar oscillation modes, arising from a magnetic greenhouse effect that scatters and traps oscillation-mode energy within the core of the star. The Kepler satellite has observed a few dozen red giants with depressed dipole modes, which we interpret as stars with strongly magnetized cores. We find that field strengths larger than ~10(5) gauss may produce the observed depression, and in one case we infer a minimum core field strength of ≈10(7) gauss. Copyright © 2015, American Association for the Advancement of Science.

  17. An Assessment of Magnetic Conditions for Strong Coronal Heating in Solar Active Regions by Comparing Observed Loops with Computed Potential Field Lines

    NASA Technical Reports Server (NTRS)

    Gary, G. A.; Moore, R. L.; Porter, J. G.; Falconer, D. A.

    1999-01-01

    We report further results on the magnetic origins of coronal heating found from registering coronal images with photospheric vector magnetograms. For two complementary active regions, we use computed potential field lines to examine the global non-potentiality of bright extended coronal loops and the three-dimensional structure of the magnetic field at their feet, and assess the role of these magnetic conditions in the strong coronal heating in these loops. The two active regions are complementary, in that one is globally potential and the other is globally nonpotential, while each is predominantly bipolar, and each has an island of included polarity in its trailing polarity domain. We find the following: (1) The brightest main-arch loops of the globally potential active region are brighter than the brightest main- arch loops of the globally strongly nonpotential active region. (2) In each active region, only a few of the mainarch magnetic loops are strongly heated, and these are all rooted near the island. (3) The end of each main-arch bright loop apparently bifurcates above the island, so that it embraces the island and the magnetic null above the island. (4) At any one time, there are other main-arch magnetic loops that embrace the island in the same manner as do the bright loops but that are not selected for strong coronal heating. (5) There is continual microflaring in sheared core fields around the island, but the main-arch bright loops show little response to these microflares. From these observational and modeling results we draw the following conclusions: (1) The heating of the main-arch bright loops arises mainly from conditions at the island end of these loops and not from their global non-potentiality. (2) There is, at most, only a loose coupling between the coronal heating in the bright loops of the main arch and the coronal heating in the sheared core fields at their feet, although in both the heating is driven by conditions/events in and around the

  18. Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ren, Jie; Zong, Q. G.; Miyoshi, Y.

    Here, we report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event are suggestive of the drift-bounce resonance mechanism. The correlation between enhanced energy fluxes and ULF waves leads to the conclusions thatmore » plasmaspheric dynamics is strongly affected by ULF waves. Van Allen Probe A and B, GOES 13, GOES 15 and MMS 1 observations suggest ULF waves in the event were strongest on the dusk-side magnetosphere. Measurements from MMS 1 contain no evidence of an external wave source during the period when ULF waves and injected energetic protons with a bump-on-tail distribution were detected by Van Allen Probe B. This suggests that the observed ULF waves were probably excited by a localized drift-bounce resonant instability, with the free energy supplied by substorm-injected energetic protons. The observations by Van Allen Probe B suggest that energy transfer between particle species in different energy ranges can take place through the action of ULF waves, demonstrating the important role of these waves in the dynamical processes of the inner magnetosphere.« less

  19. Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation

    DOE PAGES

    Ren, Jie; Zong, Q. G.; Miyoshi, Y.; ...

    2017-08-30

    Here, we report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event are suggestive of the drift-bounce resonance mechanism. The correlation between enhanced energy fluxes and ULF waves leads to the conclusions thatmore » plasmaspheric dynamics is strongly affected by ULF waves. Van Allen Probe A and B, GOES 13, GOES 15 and MMS 1 observations suggest ULF waves in the event were strongest on the dusk-side magnetosphere. Measurements from MMS 1 contain no evidence of an external wave source during the period when ULF waves and injected energetic protons with a bump-on-tail distribution were detected by Van Allen Probe B. This suggests that the observed ULF waves were probably excited by a localized drift-bounce resonant instability, with the free energy supplied by substorm-injected energetic protons. The observations by Van Allen Probe B suggest that energy transfer between particle species in different energy ranges can take place through the action of ULF waves, demonstrating the important role of these waves in the dynamical processes of the inner magnetosphere.« less

  20. The Universe Going Green: Extraordinarily Strong [OIII]5007 in Typical Dwarf Galaxies at z~3

    NASA Astrophysics Data System (ADS)

    Malkan, Matthew Arnold; Cohen, Daniel

    2017-01-01

    We constructed the average SEDs of U-dropout galaxies in the Subaru Deep Field. This sample contains more than 5000 Lyman-break galaxies at z~3. Their average near- and mid-IR colors were obtained by stacking JHK and IRAC imaging, in bins of stellar mass. At the lowest mass bins an increasingly strong excess flux is seen in the K filter. This excess can reach 1 magnitude in the broadband filter, and we attribute it to strong \\OIII $\\lambda{5007}$ line emission. The equivalent width is extraordinarily high, reaching almost 1000\\Ang\\ for the average z=3 galaxy at an i magnitude of 27. Such extreme [OIII] emission is very rare in the current epoch, only seen in a handful of metal-deficient dwarf starbursts sometimes referred to as ''Green Peas". In contrast, extreme [OIII]--strong enough to dominate the entire broad-band SED--was evidently the norm for faint galaxies at high redshift. We present evidence that these small but numerous galaxies were primarily responsible for the reionization of the Universe.

  1. Results of Sustained Observations from SABSOON

    NASA Astrophysics Data System (ADS)

    Seim, H.; Nelson, J.

    2001-12-01

    A variety of meteorological and oceanographic data being collected on the continental shelf off Georgia by the South Atlantic Bight Synoptic Offshore Observational Network (SABSOON) permit an examination of episodic and seasonal phenomena operative on the shelf. Data are collected at offshore platforms and transmitted to shore in near-real time and made available on the project website. Examples of data collected since 1999 are presented that illustrate some of processes being addressed using the network. Maximum winds occur during remarkably energetic downbursts observed in spring and summer, associated with the passage of squalls over the coastal ocean. Peak wind speed at 50 m height exceed 40 ms and air temperature drops by 4 oC or more in less than 6 minutes, often accompanied by large changes in humidity and heavy rainfall, suggesting down draft of air from aloft. These events may play an important role in the offshore transport of continentally-derived material. Continuous ADCP measurements are being used to examine the seasonality of cross-shelf exchange and its relationship to the cross-shelf density gradient. The low-frequency cross-shelf circulation changes sign when the cross-shelf density gradient changes sign. Vertical stratification is surprisingly episodic, and maximum stratification has occurred in the winter and spring associated with appearance of long-salinity surface lens and may be associated with baroclinic instabilities. Strong stratification has also been observed in summer during Gulf Stream-derived intrusions onto the shelf, during which time the upper and lower layers become largely decoupled. Continuous optical measurements of above-water and in-water irradiance (PAR) show the mid-shelf surface sediments are often in the euphotic zone. Chlorophyll fluorescence (stimulated) shows strong light-dependent diurnal variability in near-surface waters and evidence of resuspension of benthic diatoms during storm events, particularly in the early

  2. X-radiation from clusters of galaxies: Spectral evidence for a hot evolved gas

    NASA Technical Reports Server (NTRS)

    Serlemitsos, P. J.; Smith, B. W.; Boldt, E. A.; Holt, S. S.; Swank, J. H.

    1976-01-01

    OSO-8 observations of the X-ray flux in the range 2-60 keV from the Virgo, Perseus, and Coma Clusters provide strong evidence for the thermal origin of the radiation, including iron line emission. The data are adequately described by emission from an isothermal plasma with an iron abundance in near agreement with cosmic levels. A power law description is generally less acceptable and is ruled out in the case of Perseus. Implications on the origin of the cluster gas are discussed.

  3. Patent Foramen Ovale With Atrial Septal Aneurysm Is Strongly Associated With Migraine With Aura: A Large Observational Study.

    PubMed

    Snijder, Roel J R; Luermans, Justin G L M; de Heij, Albert H; Thijs, Vincent; Schonewille, Wouter J; Van De Bruaene, Alexander; Swaans, Martin J; Budts, Werner I H L; Post, Martijn C

    2016-12-01

    A patent foramen ovale (PFO) with atrial septal aneurysm (ASA) has been identified as a risk factor for cryptogenic stroke. Patients with migraine with aura (MA) appear to be at risk for silent brain infarction, which might be related to the presence of a PFO. However, the association between MA and PFO with ASA has never been reported. We examined this association in a large observational study. Patients (>18 years) who underwent an agitated saline transesophageal echocardiography (cTEE) at our outpatient clinics within a timeframe of 4 years were eligible to be included. Before cTEE they received a validated headache questionnaire. Two neurologists diagnosed migraine with or without aura according to the International Headache Criteria. A total of 889 patients (mean age 56.4±14.3 years, 41.7% women) were included. A PFO was present in 23.2%, an isolated ASA in 2.7%, and a PFO with ASA in 6.9%. The occurrence of migraine was 18.9%; the occurrence of MA was 8.1%. The prevalence of PFO with ASA was significantly higher in patients with MA compared to patients without migraine (18.1% vs 6.1%; OR 3.72, 95% CI 1.86-7.44, P<0.001). However, a PFO without ASA was not significantly associated with MA (OR 1.50, 95% CI 0.79-2.82, P=0.21). Interestingly, a PFO with ASA was strongly associated with MA (OR 2.71, 95% CI 1.23-5.95, P=0.01). In this large observational study, PFO with ASA was significantly associated with MA only. PFO closure studies should focus on this specific intra-atrial anomaly. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  4. In Situ Observation of Intermittent Dissipation at Kinetic Scales in the Earth's Magnetosheath

    NASA Astrophysics Data System (ADS)

    Chasapis, Alexandros; Matthaeus, W. H.; Parashar, T. N.; Wan, M.; Haggerty, C. C.; Pollock, C. J.; Giles, B. L.; Paterson, W. R.; Dorelli, J.; Gershman, D. J.; Torbert, R. B.; Russell, C. T.; Lindqvist, P.-A.; Khotyaintsev, Y.; Moore, T. E.; Ergun, R. E.; Burch, J. L.

    2018-03-01

    We present a study of signatures of energy dissipation at kinetic scales in plasma turbulence based on observations by the Magnetospheric Multiscale mission (MMS) in the Earth’s magnetosheath. Using several intervals, and taking advantage of the high-resolution instrumentation on board MMS, we compute and discuss several statistical measures of coherent structures and heating associated with electrons, at previously unattainable scales in space and time. We use the multi-spacecraft Partial Variance of Increments (PVI) technique to study the intermittent structure of the magnetic field. Furthermore, we examine a measure of dissipation and its behavior with respect to the PVI as well as the current density. Additionally, we analyze the evolution of the anisotropic electron temperature and non-Maxwellian features of the particle distribution function. From these diagnostics emerges strong statistical evidence that electrons are preferentially heated in subproton-scale regions of strong electric current density, and this heating is preferentially in the parallel direction relative to the local magnetic field. Accordingly, the conversion of magnetic energy into electron kinetic energy occurs more strongly in regions of stronger current density, a finding consistent with several kinetic plasma simulation studies and hinted at by prior studies using lower resolution Cluster observations.

  5. Angular-momentum-assisted dissociation of CO in strong optical fields

    NASA Astrophysics Data System (ADS)

    Mullin, Amy; Ogden, Hannah; Murray, Matthew; Liu, Qingnan; Toro, Carlos

    2017-04-01

    Filaments are produced in CO gas by intense, chirped laser pulses. Visible emission from C2 is observed as a result of chemical reactions of highly excited CO. At laser intensities greater than 1014 W cm-2, the C2 emission shows a strong dependence on laser polarization. Oppositely chirped pulses of light with ω0 = 800 nm are recombined spatially and temporally to generate angularly accelerating electric fields (up to 30 THz) that either have an instantaneous linear polarization or act as a dynamic polarization grating that oscillates among linear and circular polarizations. The angularly accelerating linear polarization corresponds to an optical centrifuge that concurrently drives molecules into high rotational states (with J 50) and induces strong-field dissociation. Higher order excitation is observed for the time-varying laser polarization configuration that does not induce rotational excitation. The results indicate that the presence of rotational angular momentum lowers the threshold for CO dissociation in strong optical fields by coupling nuclear and electronic degrees of freedom. Support from NSF CHE-1058721 and the University of Maryland.

  6. New strong motion network in Georgia: basis for specifying seismic hazard

    NASA Astrophysics Data System (ADS)

    Kvavadze, N.; Tsereteli, N. S.

    2017-12-01

    Risk created by hazardous natural events is closely related to sustainable development of the society. Global observations have confirmed tendency of growing losses resulting from natural disasters, one of the most dangerous and destructive if which are earthquakes. Georgia is located in seismically active region. So, it is imperative to evaluate probabilistic seismic hazard and seismic risk with proper accuracy. National network of Georgia includes 35 station all of which are seismometers. There are significant gaps in strong motion recordings, which essential for seismic hazard assessment. To gather more accelerometer recordings, we have built a strong motion network distributed on the territory of Georgia. The network includes 6 stations for now, with Basalt 4x datalogger and strong motion sensor Episensor ES-T. For each site, Vs30 and soil resonance frequencies have been measured. Since all but one station (Tabakhmelam near Tbilisi), are located far from power and internet lines special system was created for instrument operation. Solar power is used to supply the system with electricity and GSM/LTE modems for internet access. VPN tunnel was set up using Raspberry pi, for two-way communication with stations. Tabakhmela station is located on grounds of Ionosphere Observatory, TSU and is used as a hub for the network. This location also includes a broadband seismometer and VLF electromagnetic waves observation antenna, for possible earthquake precursor studies. On server, located in Tabakhmela, the continues data is collected from all the stations, for later use. The recordings later will be used in different seismological and engineering problems, namely selecting and creating GMPE model for Caucasus, for probabilistic seismic hazard and seismic risk evaluation. These stations are a start and in the future expansion of strong motion network is planned. Along with this, electromagnetic wave observations will continue and additional antennas will be implemented

  7. High-latitude observations of solar wind streams and coronal holes

    NASA Technical Reports Server (NTRS)

    Ricket, B. J.; Sime, D. G.; Crockett, W. R.; Tousey, R.; Sheeley, N. R., Jr.

    1976-01-01

    Interplanetary scintillation observations of the solar wind velocity during 1973 and the first part of 1974 reveal several corotating high-speed streams. These streams, of heliographic latitudes from +40 deg to -60 deg, have been mapped back to the vicinity of the sun and have been compared with coronal holes identified in wide band XUV solar images taken during the manned portions of the Skylab mission. There is some evidence that the high-speed streams are preferentially associated with coronal holes and that they can spread out from the hole boundaries up to about 20 deg in latitude. However, this association is not one to one; streams are observed which do not map back to coronal holes, and holes are observed which do not lie at the base of streams. To the extent that a statistical interpretation is possible the association is not highly significant, but individual consideration of streams and holes suggests that the statistical result is biased somewhat against a strong correlation.

  8. A new X-ray spectral observation of NGC 1068

    NASA Technical Reports Server (NTRS)

    Marshall, F. E.; Netzer, H.; Arnaud, K. A.; Boldt, E. A.; Holt, S. S.; Jahoda, K. M.; Kelley, R.; Mushotzky, R. F.; Petre, R.; Serlemitsos, P. J.

    1993-01-01

    A new X-ray observation of NGC 1068, in which improved spectral resolution (R is approximately equal to 40) and broad energy range provide important new constraints on models for this galaxy, is reported. The observed X-ray continuum of NGC 1068 from 0.3 to 10 keV is well fitted as the sum of two power-law spectra with no evidence for absorption intrinsic to the source. Strong Fe K emission lines with a total equivalent width of 2700 eV were detected due to iron less ionized than Fe XX and to iron more ionized than Fe XXIII. No evidence was seen for lines due to the recombination of highly ionized oxygen with an upper limit for the O Ly-alpha emission line of 40 eV. The discovery of multiple Fe K and Fe L emission lines indicates a broad range of ionization states for this gas. The X-ray emission from the two components is modeled for various geometries using a photoionization code that calculates the temperature and ionization state of the gas. Typical model parameters are a total Compton depth of a few percent, an inner boundary of the hot component of about 1 pc, and an inner boundary of the warm component of about 20 pc.

  9. Identifying the Tunneling Site in Strong-Field Ionization of H_{2}^{+}.

    PubMed

    Liu, Kunlong; Barth, Ingo

    2017-12-15

    The tunneling site of the electron in a molecule exposed to a strong laser field determines the initial position of the ionizing electron and, as a result, has a large impact on the subsequent ultrafast electron dynamics on the polyatomic Coulomb potential. Here, the tunneling site of the electron of H_{2}^{+} ionized by a strong circularly polarized (CP) laser pulse is studied by numerically solving the time-dependent Schrödinger equation. We show that the electron removed from the down-field site is directly driven away by the CP field and the lateral photoelectron momentum distribution (LPMD) exhibits a Gaussian-like distribution, whereas the corresponding LPMD of the electron removed from the up-field site differs from the Gaussian shape due to the Coulomb focusing and scattering by the down-field core. Our current study presents the direct evidence clarifying a long-standing controversy over the tunneling site in H_{2}^{+} and raises the important role of the tunneling site in strong-field molecular ionization.

  10. Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope.

    PubMed

    Nichols, J D; Badman, S V; Baines, K H; Brown, R H; Bunce, E J; Clarke, J T; Cowley, S W H; Crary, F J; Dougherty, M K; Gérard, J-C; Grocott, A; Grodent, D; Kurth, W S; Melin, H; Mitchell, D G; Pryor, W R; Stallard, T S

    2014-05-28

    We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current.

  11. Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope

    PubMed Central

    Nichols, J D; Badman, S V; Baines, K H; Brown, R H; Bunce, E J; Clarke, J T; Cowley, S W H; Crary, F J; Dougherty, M K; Gérard, J-C; Grocott, A; Grodent, D; Kurth, W S; Melin, H; Mitchell, D G; Pryor, W R; Stallard, T S

    2014-01-01

    We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current. PMID:26074636

  12. Coupling between strong warm ENSO events and the phase of the stratospheric QBO.

    NASA Astrophysics Data System (ADS)

    Christiansen, Bo

    2017-04-01

    Although there in general are no significant long-term correlations between the QBO and the ENSO in observations we find that the QBO and the ENSO were aligned in the 3 to 4 years after the three strong warm ENSO events in 1982, 1997, and 2015. We study this possible connection between the QBO and the ENSO with a new version of the EC-Earth model which includes non-orographic gravity waves and a well modeled QBO. We analyze the modeled QBO in ensembles consisting of 10 AMIP-type experiments with climatological SSTs and 10 experiments with observed daily SSTs. The model experiments cover the period 1982-2013. For the ENSO we use the multivariate index (MEI). As expected the coherence is strong and statistically significant in the equatorial troposphere in the ensemble with observed SSTs. Here the coherence is a measure of the alignment of the ensemble members. In the ensemble with observed SSTs we find a strong and significant alignment of the ensemble members in the equatorial stratospheric winds in the 2 to 4 years after the strong ENSO event in 1997. This alignment also includes the observed QBO. No such alignment is found in the ensemble with climatological SSTs. These results indicate that strong warm ENSO events can directly influence the phase of the QBO. An open and maybe related question is what caused the anomalous QBO in 2016. This behaviour, which is unprecedented in the 50-60 years with data, has been described as a hiccup or a death-spiral. At least it is clear that in the last 18 months the QBO has been stuck in the same corner of the phase-space spanned by its two leading principal components. The possible connection to the ENSO will be investigated.

  13. Observational Evidence for the Associated Formation of Blobs and Raining Inflows in the Solar Corona

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sanchez-Diaz, E.; Rouillard, A. P.; Lavraud, B.

    The origin of the slow solar wind is still a topic of much debate. The continual emergence of small transient structures from helmet streamers is thought to constitute one of the main sources of the slow wind. Determining the height at which these transients are released is an important factor in determining the conditions under which the slow solar wind forms. To this end, we have carried out a multipoint analysis of small transient structures released from a north–south tilted helmet streamer into the slow solar wind over a broad range of position angles during Carrington Rotation 2137. Combining themore » remote-sensing observations taken by the Solar-TErrestrial RElations Observatory ( STEREO ) mission with coronagraphic observations from the SOlar and Heliospheric Observatory ( SOHO ) spacecraft, we show that the release of such small transient structures (often called blobs), which subsequently move away from the Sun, is associated with the concomitant formation of transient structures collapsing back toward the Sun; the latter have been referred to by previous authors as “raining inflows.” This is the first direct association between outflowing blobs and raining inflows, which locates the formation of blobs above the helmet streamers and gives strong support that the blobs are released by magnetic reconnection.« less

  14. Observation of strong Kondo like features and co-tunnelling in superparamagnetic GdCl3 filled 1D nanomagnets

    NASA Astrophysics Data System (ADS)

    Ncube, S.; Coleman, C.; de Sousa, A. S.; Nie, C.; Lonchambon, P.; Flahaut, E.; Strydom, A.; Bhattacharyya, S.

    2018-06-01

    Filling of carbon nanotubes has been tailored over years to modify the exceptional properties of the 1-dimensional conductor for magnetic property based applications. Hence, such a system exploits the spin and charge property of the electron, analogous to a quantum conductor coupled to magnetic impurities, which poses an interesting scenario for the study of Kondo physics and related phenomena. We report on the electronic transport properties of MWNTs filled with GdCl3 nanomagnets, which clearly show the co-existence of Kondo correlation and cotunelling within the superparamagnetic limit. The Fermi liquid description of the Kondo effect and the interpolation scheme are fitted to the resistance-temperature dependence yielding the onset of the Kondo scattering temperature and a Kondo temperature for this nanocomposite, respectively. Cotunneling of conduction electrons interfering with a Kondo type interaction has been verified from the exponential decay of the intensity of the fano shaped nonzero bias anomalous conductance peaks, which also show strong resonant features observed only in GdCl3 filled MWNT devices. Hence, these features are explained in terms of magnetic coherence and spin-flip effects along with the competition between the Kondo effect and co-tunneling. This study raises a new possibility of tailoring magnetic interactions for spintronic applications in carbon nanotube systems.

  15. ASCA Observations of "Type 2" LINERs Evidence for a Stellar Source of Ionization

    NASA Technical Reports Server (NTRS)

    Terashima, Yuichi; Ho, Luis C.; Ptak, Andrew F.; Mushotzky, Richard F.; Serlemitsos, Peter J.; Yaqoob, Tahir; Kunieda, Hideyo

    1999-01-01

    We present ASCA observations of LINERs without broad H.alpha emission in their optical spectra. The sample of "type 2" LINERs consists of NGC 404, 4111, 4192, 4457, and 4569. We have detected X-ray emission from all the objects except for NGC 404; among the detected objects are two so-called transition objects (NGC 4192 and NGC 4569), which have been postulated to be composite nuclei having both an H II region and a LINER component. The images of NGC 4111 and NGC 4569 in the soft (0.5-2 keV) and hard (2-7 keV) X-ray bands are extended on scales of several kpc. The X-ray spectra of NGC 4111, NGC 4457 and NGC 4569 are well fitted by a two-component model that consists of soft thermal emission with kT approximately 0.65 keV and a hard component represented by a power law (photon index approximately 2) or by thermal bremsstrahlung emission (kT approximately several keV). The extended hard X-rays probably come from discrete sources, while the soft emission most likely originates from hot gas produced by active star formation in the host galaxy. We have found no clear evidence for the presence of active galactic nuclei (AGNs) in the sample. Using black hole masses estimated from host galaxy bulge luminosities, we obtain an upper limit on the implied Eddington ratios less than 5 x 10(exp -5). If an AGN component is the primary ionization source of the optical emission lines, then it must be heavily obscured with a column density significantly larger than 10(exp 23)/sq cm, since the observed X-ray luminosity is insufficient to drive the luminosities of the optical emission lines. Alternatively, the optical emission could be ionized by a population of exceptionally hot stars. This interpretation is consistent with the small [O I] lambda6300/H.alpha ratios observed in these sources, the ultraviolet spectral characteristics in the cases where such information exists, and the X-ray results reported here. We also analyze the X-ray properties of NGC 4117, a low

  16. Initial observations of the pioneer venus orbiter solar wind plasma experiment.

    PubMed

    Wolfe, J; Intriligator, D S; Mihalov, J; Collard, H; McKibbin, D; Whitten, R; Barnes, A

    1979-02-23

    Initial results of observations of the solar wind interaction with Venus indicate that Venus has a well-defined, strong, standing bow shock wave. Downstream from the shock, an ionosheath is observed in which the compressed and heated postshock plasma evidently interacts directly with the Venus ionosphere. Plasma ion velocity deflections observed within the ionosheath are consistent with flow around the blunt shape of the ionopause. The ionopause boundary is observed and defined by this experiment as the location where the ionosheath ion flow is first excluded. The positions of the bow shock and ionopause are variable and appear to respond to changes in the external solar wind pressure. Near the terminator the bow shock was observed at altitudes of approximately 4600 to approximately 12,000 kilometers. The ionopause altitutde ranged fromn as low as approximately 450 to approximately 1950 kilometers. Within the Venus ionosphere low-energy ions (energy per untit charge < 30 volts) were detected and have been tentatively idtentified as nonflowing ionospheric ions incident from a direction along the spacecraft velocity vector.

  17. Cavity Quantum Acoustic Device in the Multimode Strong Coupling Regime

    NASA Astrophysics Data System (ADS)

    Moores, Bradley A.; Sletten, Lucas R.; Viennot, Jeremie J.; Lehnert, K. W.

    2018-06-01

    We demonstrate an acoustical analog of a circuit quantum electrodynamics system that leverages acoustic properties to enable strong multimode coupling in the dispersive regime while suppressing spontaneous emission to unconfined modes. Specifically, we fabricate and characterize a device that comprises a flux tunable transmon coupled to a 300 μ m long surface acoustic wave resonator. For some modes, the qubit-cavity coupling reaches 6.5 MHz, exceeding the cavity loss rate (200 kHz), qubit linewidth (1.1 MHz), and the cavity free spectral range (4.8 MHz), placing the device in both the strong coupling and strong multimode regimes. With the qubit detuned from the confined modes of the cavity, we observe that the qubit linewidth strongly depends on its frequency, as expected for spontaneous emission of phonons, and we identify operating frequencies where this emission rate is suppressed.

  18. An optimized absorbing potential for ultrafast, strong-field problems

    NASA Astrophysics Data System (ADS)

    Yu, Youliang; Esry, B. D.

    2018-05-01

    Theoretical treatments of strong-field physics have long relied on the numerical solution of the time-dependent Schrödinger equation. The most effective such treatments utilize a discrete spatial representation—a grid. Since most strong-field observables relate to the continuum portion of the wave function, the boundaries of the grid—which act as hard walls and thus cause reflection—can substantially impact the observables. Special care thus needs to be taken. While there exist a number of attempts to solve this problem—e.g., complex absorbing potentials and masking functions, exterior complex scaling, and coordinate scaling—none of them are completely satisfactory. The first of these is arguably the most popular, but it consumes a substantial fraction of the computing resources in any given calculation. Worse, this fraction grows with the dimensionality of the problem. In addition, no systematic way to design such a potential has been used in the strong-field community. In this work, we address these issues and find a much better solution. By comparing with previous widely used absorbing potentials, we find a factor of 3–4 reduction in the absorption range, given the same level of absorption over a specified energy interval.

  19. 77 FR 16131 - Establishing a White House Council on Strong Cities, Strong Communities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-20

    ... Order 13602 of March 15, 2012 Establishing a White House Council on Strong Cities, Strong Communities By... inclusive, it is hereby ordered as follows: Section 1. Policy. Cities, towns, and regions across our Nation... collaboration, my Administration established the Strong Cities, Strong Communities (SC2) pilot initiative. By...

  20. Observations of reconnection of interplanetary and lobe magnetic field lines at the high-latitude magnetopause

    NASA Technical Reports Server (NTRS)

    Gosling, J. T.; Thomsen, M. F.; Bame, S. J.; Elphic, R. C.; Russell, C. T.

    1991-01-01

    Results are presented of ISEE 2 observations of plasma accelerations obtained at the high-latitude (lobe) magnetopause at a time when the local magnetosheath and magnetospheric magnetic fields were nearly oppositely directed and the flow speed in the magnetosheath, V(s), was nearly equal to the local Alfven speed, V(A). The observations provide direct evidence for the rereconnection of the open field lines of the tail lobes with the IMF, when the magnetic field shear is large. It is pointed out, however, that, since V(s) was almost equal to V(A), it is unlikely that the rereconnection is associated with the strong sunward convection in the polar cap.

  1. Herschel Extreme Lensing Line Observations: Dynamics of Two Strongly Lensed Star-Forming Galaxies near Redshift z=2*

    NASA Technical Reports Server (NTRS)

    Rhoads, James E.; Rigby, Jane Rebecca; Malhotra, Sangeeta; Allam, Sahar; Carilli, Chris; Combes, Francoise; Finkelstein, Keely; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; hide

    2014-01-01

    We report on two regularly rotating galaxies at redshift z approx. = 2, using high-resolution spectra of the bright [C microns] 158 micrometers emission line from the HIFI instrument on the Herschel Space Observatory. Both SDSS090122.37+181432.3 ("S0901") and SDSSJ120602.09+514229.5 ("the Clone") are strongly lensed and show the double-horned line profile that is typical of rotating gas disks. Using a parametric disk model to fit the emission line profiles, we find that S0901 has a rotation speed of v sin(i) approx. = 120 +/- 7 kms(sup -1) and a gas velocity dispersion of (standard deviation)g < 23 km s(sup -1) (1(standard deviation)). The best-fitting model for the Clone is a rotationally supported disk having v sin(i) approx. = 79 +/- 11 km s(sup -1) and (standard deviation)g 4 kms(sup -1) (1(standard deviation)). However, the Clone is also consistent with a family of dispersion-dominated models having (standard deviation)g = 92 +/- 20 km s(sup -1). Our results showcase the potential of the [C microns] line as a kinematic probe of high-redshift galaxy dynamics: [C microns] is bright, accessible to heterodyne receivers with exquisite velocity resolution, and traces dense star-forming interstellar gas. Future [C microns] line observations with ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.

  2. The strong UV source in the active E Galaxy NGC 4552

    NASA Technical Reports Server (NTRS)

    Oconnell, R. W.; Thuan, T. X.; Puschell, J. J.

    1986-01-01

    1200-3200 A IUE spectra of the nucleus of NGC 4552 (M89) were obtained in order to investigate the nature of the strong 10 micron source in this Galaxy. There is a strong, extended UV source in NGC 4552 which has a spatial distribution nearly identical with that at optical wavelengths and is undoubedly stellar in origin. Its properties are consistent with the correlation between UV source strength and metallicity pointed out by Faber (1983). There is no evidence for a nonthermal point source in the UV. It appears unlikely that the 10 micron emission is from heated dust grains. Instead, it is believed the 10 micron radiation is nonthermal in origin, implying a remarkably small size of only 0.1 AU for this source.

  3. Sodium Lidar-observed Strong Inertia-gravity Wave Activities in the Mesopause Region over Fort Collins, Colorado (41 deg N, 105 deg W)

    NASA Technical Reports Server (NTRS)

    Li, Tao; She, C. -Y.; Liu, Han-Li; Leblanc, Thierry; McDermid, I. Stuart

    2007-01-01

    In December 2004, the Colorado State University sodium lidar system at Fort Collins, Colorado (41 deg N, 105 deg W), conducted an approximately 80-hour continuous campaign for the simultaneous observations of mesopause region sodium density, temperature, and zonal and meridional winds. This data set reveals the significant inertia-gravity wave activities with a period of approximately 18 hours, which are strong in both wind components since UT day 338 (second day of the campaign), and weak in temperature and sodium density. The considerable variability of wave activities was observed with both wind amplitudes growing up to approximately 40 m/s at 95-100 km in day 339 and then decreasing dramatically in day 340. We also found that the sodium density wave perturbation is correlated in phase with temperature perturbation below 90 km, and approximately 180 deg out of phase above. Applying the linear wave theory, we estimated the wave horizontal propagation direction, horizontal wavelength, and apparent horizontal phase speed to be approximately 25 deg south of west, approximately 1800 +/- 150 km, and approximately 28 +/- 2 m/s, respectively of wave intrinsic period, intrinsic phase speed, and vertical wavelength were also estimated. While the onset of enhanced inertia-gravity wave amplitude in the night of 338 was observed to be in coincidence with short-period gravity wave breaking via convective instability, the decrease of inertia-gravity wave amplitude after noon of day 339 was also observed to coincide with the development of atmospheric dynamical instability layers with downward phase progression clearly correlated with the 18-hour inertia-gravity wave, suggesting likely breaking of this inertia-gravity wave via dynamical (shear) instability.

  4. Testing the Speed of Gravitational Waves over Cosmological Distances with Strong Gravitational Lensing.

    PubMed

    Collett, Thomas E; Bacon, David

    2017-03-03

    Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al. [J. Cosmol. Astropart. Phys.10 (2014) 080JCAPBP1475-751610.1088/1475-7516/2014/10/080] forecast that 50-100 strongly lensed GW events will be observed each year with the Einstein Telescope. A single strongly lensed GW event would produce robust constraints on c_{GW}/c_{γ} at the 10^{-7} level, if a high-energy EM counterpart is observed within the field of view of an observing γ-ray burst monitor.

  5. Highly Resolved Measurements of a Developing Strong Collisional Plasma Shock

    DOE PAGES

    Rinderknecht, Hans G.; Park, H. -S.; Ross, J. S.; ...

    2018-03-02

    In this paper, the structure of a strong collisional shock front forming in a plasma is directly probed for the first time in laser-driven gas-jet experiments. Thomson scattering of a 526.5 nm probe beam was used to diagnose temperature and ion velocity distribution in a strong shock (more » $$M{\\sim}11$$) propagating through a low-density ($${\\rho}{\\sim}0.01\\text{ }\\text{ }\\mathrm{mg}/\\mathrm{cc}$$) plasma composed of hydrogen. A forward-streaming population of ions traveling in excess of the shock velocity was observed to heat and slow down on an unmoving, unshocked population of cold protons, until ultimately the populations merge and begin to thermalize. Finally, instabilities are observed during the merging, indicating a uniquely plasma-phase process in shock front formation.« less

  6. Highly Resolved Measurements of a Developing Strong Collisional Plasma Shock

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rinderknecht, Hans G.; Park, H. -S.; Ross, J. S.

    In this paper, the structure of a strong collisional shock front forming in a plasma is directly probed for the first time in laser-driven gas-jet experiments. Thomson scattering of a 526.5 nm probe beam was used to diagnose temperature and ion velocity distribution in a strong shock (more » $$M{\\sim}11$$) propagating through a low-density ($${\\rho}{\\sim}0.01\\text{ }\\text{ }\\mathrm{mg}/\\mathrm{cc}$$) plasma composed of hydrogen. A forward-streaming population of ions traveling in excess of the shock velocity was observed to heat and slow down on an unmoving, unshocked population of cold protons, until ultimately the populations merge and begin to thermalize. Finally, instabilities are observed during the merging, indicating a uniquely plasma-phase process in shock front formation.« less

  7. Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature.

    PubMed

    Kleemann, Marie-Elena; Chikkaraddy, Rohit; Alexeev, Evgeny M; Kos, Dean; Carnegie, Cloudy; Deacon, Will; de Pury, Alex Casalis; Große, Christoph; de Nijs, Bart; Mertens, Jan; Tartakovskii, Alexander I; Baumberg, Jeremy J

    2017-11-03

    Strong coupling of monolayer metal dichalcogenide semiconductors with light offers encouraging prospects for realistic exciton devices at room temperature. However, the nature of this coupling depends extremely sensitively on the optical confinement and the orientation of electronic dipoles and fields. Here, we show how plasmon strong coupling can be achieved in compact, robust, and easily assembled gold nano-gap resonators at room temperature. We prove that strong-coupling is impossible with monolayers due to the large exciton coherence size, but resolve clear anti-crossings for greater than 7 layer devices with Rabi splittings exceeding 135 meV. We show that such structures improve on prospects for nonlinear exciton functionalities by at least 10 4 , while retaining quantum efficiencies above 50%, and demonstrate evidence for superlinear light emission.

  8. Observations at mercury encounter by the plasma science experiment on mariner 10.

    PubMed

    Ogilvie, K W; Scudder, J D; Hartle, R E; Siscoe, G L; Bridge, H S; Lazarus, A J; Asbridge, J R; Bame, S J; Yeates, C M

    1974-07-12

    A fully developed bow shock and magnetosheath were observed near Mercury, providing unambiguous evidence for a strong interaction between Mercury and the solar wind. Inside the sheath there is a distinct region analogous to the magnetosphere or magnetotail of Earth, populated by electrons with lower density and higher temperature than the electrons observed in the solar wind or magnetosheath. At the time of encounter, conditions were such that a perpendicular shock was observed on the inbound leg and a parallel shock was observed on the outbound leg of the trajectory, and energetic plasma electron events were detected upstream from the outbound shock crossing. The interaction is most likely not atmospheric, but the data clearly indicate that the obstacle to solar wind flow is magnetic, either intrinsic or induced. The particle fluxes and energy spectra showed large variations while the spacecraft was inside the magnetosphere, and these variations could be either spatial or temporal.

  9. Earth Glint Observations Conducted During the Deep Impact Spacecraft Flyby

    NASA Technical Reports Server (NTRS)

    Barry, R. K.; Deming, L. D.; Robinson, T.; Hewagama, T.

    2010-01-01

    We describe observations of Earth conducted using the High Resolution Instrument (HRI) - a 0.3 m f/35 telescope - on the Deep Impact (DI) spacecraft during its recent flybys. Earth was observed on five occasions: 2008-Mar-18 18:18 UT, 2008-May-28 20:05 UT, 2008-Jun-4 16:57 UT, 2009-Mar-27 16:19 and 2009-Oct-4 09:37 UT. Each set of observations was conducted over a full 24-hour rotation of Earth and a total of thirteen NIR spectra were taken on two-hour intervals during each observing period. Photometry in the 450, SSO, 650 and 8S0 nm filters was taken every fifteen minutes and every hour for the 350, 750 and 950 nm filters. The spacecraft was located over the equator for the three sets of observations in 2008, while the 2009- Mar and 2009-Oct were taken over the north and south Polar Regions, respectively. Observations of calibrator stars Canopus and Achernar were conducted on multiple occasions through all filters. The observations detected a strong specular glint not necessarily associated with a body of water. We describe spectroscopic characterization of the glint and evidence for the possibility of detection of reflection from high cirrus clouds. We describe implications for observations of extrasolar planets.

  10. Chromogravity explains {open_quotes}strong gravity{close_quotes}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ne`eman, Y.; Sijacki, D.

    1993-03-01

    In this paper the authors deal with the question of gravitational type interactions in the case of strong interaction phenomena. They present arguments which indicate that it is not necessary to invoke a gravity type interaction into QCD in order to account for observed phenomena. They argue that the gravitational type phenomena discussed in previous work is a manifestation of a class of Feynmann diagrams. These seem to generate an analog to gravity, a J=2 {open_quotes}chromograviton{close_quotes} or {open_quotes}pseudo-graviton{close_quotes} whose action effectively generates Salam`s {open_quotes}Strong Gravity{close_quotes} or {open_quotes}f-gravity{close_quotes}, withthough having to introduce the theory as an additional input.

  11. Strong size-dependent stress relaxation in electrospun polymer nanofibers

    NASA Astrophysics Data System (ADS)

    Wingert, Matthew C.; Jiang, Zhang; Chen, Renkun; Cai, Shengqiang

    2017-01-01

    Electrospun polymer nanofibers have garnered significant interest due to their strong size-dependent material properties, such as tensile moduli, strength, toughness, and glass transition temperatures. These properties are closely correlated with polymer chain dynamics. In most applications, polymers usually exhibit viscoelastic behaviors such as stress relaxation and creep, which are also determined by the motion of polymer chains. However, the size-dependent viscoelasticity has not been studied previously in polymer nanofibers. Here, we report the first experimental evidence of significant size-dependent stress relaxation in electrospun Nylon-11 nanofibers as well as size-dependent viscosity of the confined amorphous regions. In conjunction with the dramatically increasing stiffness of nano-scaled fibers, this strong relaxation enables size-tunable properties which break the traditional damping-stiffness tradeoff, qualifying electrospun nanofibers as a promising set of size-tunable materials with an unusual and highly desirable combination of simultaneously high stiffness and large mechanical energy dissipation.

  12. Strong size-dependent stress relaxation in electrospun polymer nanofibers

    DOE PAGES

    Wingert, Matthew C.; Jiang, Zhang; Chen, Renkun; ...

    2017-01-04

    Here, electrospun polymer nanofibers have garnered significant interest due to their strong size-dependent material properties, such as tensile moduli, strength, toughness, and glass transition temperatures. These properties are closely correlated with polymer chain dynamics. In most applications, polymers usually exhibit viscoelastic behaviors such as stress relaxation and creep, which are also determined by the motion of polymer chains. However, the size-dependent viscoelasticity has not been studied previously in polymer nanofibers. Here, we report the first experimental evidence of significant size-dependent stress relaxation in electrospun Nylon-11 nanofibers as well as size-dependent viscosity of the confined amorphous regions. In conjunction with themore » dramatically increasing stiffness of nano-scaled fibers, this strong relaxation enables size-tunable properties which break the traditional damping-stiffness tradeoff, qualifying electrospun nanofibers as a promising set of size-tunable materials with an unusual and highly desirable combination of simultaneously high stiffness and large mechanical energy dissipation.« less

  13. Observing functional actions affects semantic processing of tools: evidence of a motor-to-semantic priming.

    PubMed

    De Bellis, Francesco; Ferrara, Antonia; Errico, Domenico; Panico, Francesco; Sagliano, Laura; Conson, Massimiliano; Trojano, Luigi

    2016-01-01

    Recent evidence shows that activation of motor information can favor identification of related tools, thus suggesting a strict link between motor and conceptual knowledge in cognitive representation of tools. However, the involvement of motor information in further semantic processing has not been elucidated. In three experiments, we aimed to ascertain whether motor information provided by observation of actions could affect processing of conceptual knowledge about tools. In Experiment 1, healthy participants judged whether pairs of tools evoking different functional handgrips had the same function. In Experiment 2 participants judged whether tools were paired with appropriate recipients. Finally, in Experiment 3 we again required functional judgments as in Experiment 1, but also included in the set of stimuli pairs of objects having different function and similar functional handgrips. In all experiments, pictures displaying either functional grasping (aimed to use tools) or structural grasping (just aimed to move tools independently from their use) were presented before each stimulus pair. The results demonstrated that, in comparison with structural grasping, observing functional grasping facilitates judgments about tools' function when objects did not imply the same functional manipulation (Experiment 1), whereas worsened such judgments when objects shared functional grasp (Experiment 3). Instead, action observation did not affect judgments concerning tool-recipient associations (Experiment 2). Our findings support a task-dependent influence of motor information on high-order conceptual tasks and provide further insights into how motor and conceptual processing about tools can interact.

  14. Tunneling Time and Weak Measurement in Strong Field Ionization.

    PubMed

    Zimmermann, Tomáš; Mishra, Siddhartha; Doran, Brent R; Gordon, Daniel F; Landsman, Alexandra S

    2016-06-10

    Tunneling delays represent a hotly debated topic, with many conflicting definitions and little consensus on when and if such definitions accurately describe the physical observables. Here, we relate these different definitions to distinct experimental observables in strong field ionization, finding that two definitions, Larmor time and Bohmian time, are compatible with the attoclock observable and the resonance lifetime of a bound state, respectively. Both of these definitions are closely connected to the theory of weak measurement, with Larmor time being the weak measurement value of tunneling time and Bohmian trajectory corresponding to the average particle trajectory, which has been recently reconstructed using weak measurement in a two-slit experiment [S. Kocsis, B. Braverman, S. Ravets, M. J. Stevens, R. P. Mirin, L. K. Shalm, and A. M. Steinberg, Science 332, 1170 (2011)]. We demonstrate a big discrepancy in strong field ionization between the Bohmian and weak measurement values of tunneling time, and we suggest this arises because the tunneling time is calculated for a small probability postselected ensemble of electrons. Our results have important implications for the interpretation of experiments in attosecond science, suggesting that tunneling is unlikely to be an instantaneous process.

  15. Diverse convergent evidence in the genetic analysis of complex disease: coordinating omic, informatic, and experimental evidence to better identify and validate risk factors

    PubMed Central

    2014-01-01

    In omic research, such as genome wide association studies, researchers seek to repeat their results in other datasets to reduce false positive findings and thus provide evidence for the existence of true associations. Unfortunately this standard validation approach cannot completely eliminate false positive conclusions, and it can also mask many true associations that might otherwise advance our understanding of pathology. These issues beg the question: How can we increase the amount of knowledge gained from high throughput genetic data? To address this challenge, we present an approach that complements standard statistical validation methods by drawing attention to both potential false negative and false positive conclusions, as well as providing broad information for directing future research. The Diverse Convergent Evidence approach (DiCE) we propose integrates information from multiple sources (omics, informatics, and laboratory experiments) to estimate the strength of the available corroborating evidence supporting a given association. This process is designed to yield an evidence metric that has utility when etiologic heterogeneity, variable risk factor frequencies, and a variety of observational data imperfections might lead to false conclusions. We provide proof of principle examples in which DiCE identified strong evidence for associations that have established biological importance, when standard validation methods alone did not provide support. If used as an adjunct to standard validation methods this approach can leverage multiple distinct data types to improve genetic risk factor discovery/validation, promote effective science communication, and guide future research directions. PMID:25071867

  16. Postabortion Care: 20 Years of Strong Evidence on Emergency Treatment, Family Planning, and Other Programming Components

    PubMed Central

    Huber, Douglas; Curtis, Carolyn; Irani, Laili; Pappa, Sara; Arrington, Lauren

    2016-01-01

    ABSTRACT Worldwide 75 million women need postabortion care (PAC) services each year following safe or unsafe induced abortions and miscarriages. We reviewed more than 550 studies on PAC published between 1994 and 2013 in the peer-reviewed and gray literature, covering emergency treatment, postabortion family planning, organization of services, and related topics that impact practices and health outcomes, particularly in the Global South. In this article, we present findings from studies with strong evidence that have major implications for programs and practice. For example, vacuum aspiration reduced morbidity, costs, and time in comparison to sharp curettage. Misoprostol 400 mcg sublingually or 600 mcg orally achieved 89% to 99% complete evacuation rates within 2 weeks in multiple studies and was comparable in effectiveness, safety, and acceptability to manual vacuum aspiration. Misoprostol was safely introduced in several PAC programs through mid-level providers, extending services to secondary hospitals and primary health centers. In multiple studies, postabortion family planning uptake before discharge increased by 30–70 percentage points within 1–3 years of strengthening postabortion family planning services; in some cases, increases up to 60 percentage points in 4 months were achieved. Immediate postabortion contraceptive acceptance increased on average from 32% before the interventions to 69% post-intervention. Several studies found that women receiving immediate postabortion intrauterine devices and implants had fewer unintended pregnancies and repeat abortions than those who were offered delayed insertions. Postabortion family planning is endorsed by the professional organizations of obstetricians/gynecologists, midwives, and nurses as a standard of practice; major donors agree, and governments should be encouraged to provide universal access to postabortion family planning. Important program recommendations include offering all postabortion women

  17. Simultaneous Chandra X-ray, HST Ultraviolet, and Ulysses Radio Observations of Jupiter's Aurora

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; Lugaz, N.; Waite, J. H., Jr.; Cravens, T. E.; Gladstone, G. R.; Ford, P.; Grodent, D.; Bhardwaj, A.; MacDowall, R. J.

    2004-01-01

    Observations of Jupiter carried out by the Chandra ACIS-S instrument over 24-26 February, 2003, show that the auroral X-ray spectrum consists of line emission consistent with high-charge states of precipitating ions, and not a continuum as might be expected from bremsstrahlung. The part of the spectrum due to oxygen peaks around 650 eV, which indicates a high fraction of fully-stripped oxygen in the precipitating ion flux. A combination of the OVIII emission lines at 653 eV and 774 eV, as well as the OVII emission lines at 561 eV and 666 eV, are evident in the measure auroral spectrum. There is also line emission at lower energies in the spectral region extending from 250 to 350 eV, which could be from sulfur and/or carbon. The Jovian auroral X- ray spectra are significantly different from the X-ray spectra of comets. The charge state distribution of the oxygen ions implied by the measured auroral X-ray spectra strongly suggests that, independent of the source of the energetic ions - magnetospheric or solar wind - the ions have undergone additional acceleration. This spectral evidence for ion acceleration is also consistent with the relatively high intensities of the X-rays compared to the available phase space density of the (unaccelerated) source populations of solar wind or magnetospheric ions at Jupiter, which are orders of magnitude too small to explain the observed emissions. The Chandra X-ray observations were executed simultaneously with observations at ultraviolet wavelengths by the Hubble Space Telescope and at radio wavelengths by the Ulysses spacecraft. These additional data sets suggest that the source of the X-rays is magnetospheric in origin, and that the precipitating particles are accelerated by strong field-aligned electric fields, which simultaneously create both the several-MeV energetic ion population and the relativistic electrons observed in situ by Ulysses that are correlated with approximately 40 minute quasi-periodic radio outbursts.

  18. Interaction of N-hydroxyurea with strong proton donors: HCl and HF

    NASA Astrophysics Data System (ADS)

    Sałdyka, Magdalena

    2014-11-01

    An infrared spectroscopic and MP2/6-311++G(2d,2p) study of strong hydrogen bonded complexes of N-hydroxyurea (NH2CONHOH) with hydrogen halides (HCl and HF) trapped in solid argon matrices is reported. 1:1 and 1:2 complexes between N-hydroxyurea and hydrogen chloride, hydrogen fluoride have been identified in the NH2CONHOH/HCl/Ar, NH2CONHOH/HF/Ar matrices, respectively; their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes, identified for both hydrogen halide molecules, the cyclic structure stabilized by the X-H⋯O and N-H⋯X bonds is present; for the NH2CONHOH⋯HF system another isomeric 1:1 complex is also observed. Two 1:2 complexes were identified for the N-hydroxyurea-hydrogen chloride system characterised by the Cl-H⋯O and N-H⋯Cl bonds. The results of the study evidence that N-hydroxyurea is an oxygen base in the gas-phase with the carbonyl group as the strongest proton acceptor centre in the molecule.

  19. Mirror neuron system and observational learning: behavioral and neurophysiological evidence.

    PubMed

    Lago-Rodriguez, Angel; Lopez-Alonso, Virginia; Fernández-del-Olmo, Miguel

    2013-07-01

    Three experiments were performed to study observational learning using behavioral, perceptual, and neurophysiological data. Experiment 1 investigated whether observing an execution model, during physical practice of a transitive task that only presented one execution strategy, led to performance improvements compared with physical practice alone. Experiment 2 investigated whether performing an observational learning protocol improves subjects' action perception. In experiment 3 we evaluated whether the type of practice performed determined the activation of the Mirror Neuron System during action observation. Results showed that, compared with physical practice, observing an execution model during a task that only showed one execution strategy does not provide behavioral benefits. However, an observational learning protocol allows subjects to predict more precisely the outcome of the learned task. Finally, intersperse observation of an execution model with physical practice results in changes of primary motor cortex activity during the observation of the motor pattern previously practiced, whereas modulations in the connectivity between primary and non primary motor areas (PMv-M1; PPC-M1) were not affected by the practice protocol performed by the observer. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Solar-induced chlorophyll fluorescence is strongly correlated with terrestrial photosynthesis for a wide variety of biomes: First global analysis based on OCO-2 and flux tower observations.

    PubMed

    Li, Xing; Xiao, Jingfeng; He, Binbin; Arain, M Altaf; Beringer, Jason; Desai, Ankur R; Emmel, Carmen; Hollinger, David Y; Krasnova, Alisa; Mammarella, Ivan; Noe, Steffen M; Serrano Ortiz, Penélope; Rey-Sanchez, Camilo; Rocha, Adrian V; Varlagin, Andrej

    2018-05-07

    Solar-induced chlorophyll fluorescence (SIF) has been increasingly used as a proxy for terrestrial gross primary productivity (GPP). Previous work mainly evaluated the relationship between satellite-observed SIF and gridded GPP products both based on coarse spatial resolutions. Finer-resolution SIF (1.3 km × 2.25 km) measured from the Orbiting Carbon Observatory-2 (OCO-2) provides the first opportunity to examine the SIF-GPP relationship at the ecosystem scale using flux tower GPP data. However, it remains unclear how strong the relationship is for each biome and whether a robust, universal relationship exists across a variety of biomes. Here we conducted the first global analysis of the relationship between OCO-2 SIF and tower GPP for a total of 64 flux sites across the globe encompassing eight major biomes. OCO-2 SIF showed strong correlations with tower GPP at both mid-day and daily timescales, with the strongest relationship observed for daily SIF at the 757 nm (R 2 =0.72, p<0.0001). Strong linear relationships between SIF and GPP were consistently found for all biomes (R 2 =0.57-0.79, p<0.0001) except for evergreen broadleaf forests (R 2 =0.16, p<0.05) at the daily timescale. A higher slope was found for C 4 grasslands and croplands than for C 3 ecosystems. The generally consistent slope of the relationship among biomes suggests a nearly universal rather than biome-specific SIF-GPP relationship, and this finding is an important distinction and simplification compared to previous results. OCO-2 SIF generally had a better performance for predicting GPP than satellite-derived vegetation indices and a light use efficiency model. The universal SIF-GPP relationship can potentially lead to more accurate GPP estimates regionally or globally. Our findings revealed the remarkable ability of finer-resolution SIF observations from OCO-2 and other new or future missions (e.g., TROPOMI, FLEX) for estimating terrestrial photosynthesis across a wide variety of biomes and

  1. Low-Temperature Fault Creep: Strong vs. Weak, Steady vs. Episodic

    NASA Astrophysics Data System (ADS)

    Wang, K.; Gao, X.

    2017-12-01

    Unless we understand how faults creep, we do not fully understand how they produce earthquakes. However, most of the physics and geology of low-temperature creep is not known. There are two end-member types of low-temperature creep: weak creep of smooth faults and strong creep of rough faults, with a spectrum of intermediate modes in between. Most conceptual and numerical models deal with weak creep, assuming a very smooth fault with a gouge typically weakened by hydrous minerals (Harris, 2017). Less understood is strong creep. For subduction zones, strong creep appears to be common and is often associated with the subduction of large geometrical irregularities such as seamounts and aseismic ridges (Wang and Bilek, 2014). These irregularities generate fracture systems as they push against the resistance of brittle rocks. The resultant heterogeneous stress and structural environment makes it very difficult to lock the fault. The geodetically observed creep under such conditions is accomplished by the complex deformation of a 3D damage zone. Strong-creeping faults dissipate more heat than faults that produce great earthquakes (Gao and Wang, 2014). Although an integrated frictional strength of the fault is still a useful concept, the creeping mechanism is very different from frictional slip of a velocity-strengthening smooth fault. Cataclasis and pressure-solution creep in the fracture systems must be important processes in strong creep. Strong creep is necessarily non-steady and produces small and medium earthquakes. Strong creep of a megathrust can also promote the occurrence of a very special type of weak creep - episodic slow slip around the mantle wedge corner accompanied with tremor (ETS). An example is Hikurangi, where strong creep causes the frictional-viscous transition along the plate interface to occur much shallower than the mantle wedge corner, a necessary condition for ETS (Gao and Wang, 2017). Gao and Wang (2014), Strength of stick-slip and creeping

  2. Cycle frequency in standard Rock-Paper-Scissors games: Evidence from experimental economics

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Zhou, Hai-Jun; Wang, Zhijian

    2013-10-01

    The Rock-Paper-Scissors (RPS) game is a widely used model system in game theory. Evolutionary game theory predicts the existence of persistent cycles in the evolutionary trajectories of the RPS game, but experimental evidence has remained to be rather weak. In this work, we performed laboratory experiments on the RPS game and analyzed the social-state evolutionary trajectories of twelve populations of N=6 players. We found strong evidence supporting the existence of persistent cycles. The mean cycling frequency was measured to be 0.029±0.009 period per experimental round. Our experimental observations can be quantitatively explained by a simple non-equilibrium model, namely the discrete-time logit dynamical process with a noise parameter. Our work therefore favors the evolutionary game theory over the classical game theory for describing the dynamical behavior of the RPS game.

  3. Tuning the Selectivity of Catalytic Carbon Dioxide Hydrogenation over Iridium/Cerium Oxide Catalysts with a Strong Metal-Support Interaction.

    PubMed

    Li, Siwei; Xu, Yao; Chen, Yifu; Li, Weizhen; Lin, Lili; Li, Mengzhu; Deng, Yuchen; Wang, Xiaoping; Ge, Binghui; Yang, Ce; Yao, Siyu; Xie, Jinglin; Li, Yongwang; Liu, Xi; Ma, Ding

    2017-08-28

    A one-step ligand-free method based on an adsorption-precipitation process was developed to fabricate iridium/cerium oxide (Ir/CeO 2 ) nanocatalysts. Ir species demonstrated a strong metal-support interaction (SMSI) with the CeO 2 substrate. The chemical state of Ir could be finely tuned by altering the loading of the metal. In the carbon dioxide (CO 2 ) hydrogenation reaction it was shown that the chemical state of Ir species-induced by a SMSI-has a major impact on the reaction selectivity. Direct evidence is provided indicating that a single-site catalyst is not a prerequisite for inhibition of methanation and sole production of carbon monoxide (CO) in CO 2 hydrogenation. Instead, modulation of the chemical state of metal species by a strong metal-support interaction is more important for regulation of the observed selectivity (metallic Ir particles select for methane while partially oxidized Ir species select for CO production). The study provides insight into heterogeneous catalysts at nano, sub-nano, and atomic scales. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Geoarchaeological evidence of strong prehistoric earthquakes in the New Madrid (Missouri) seismic zone

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saucier, R.T.

    1991-04-01

    Sand blows and fissures that cover >10,500 km{sup 2} in northeastern Arkansas and southeastern Missouri attest to the severity of the 1811-1812 earthquake series in the New Madrid seismic zone. However, except for one occurence near New Madrid, Missouri, the region has been devoid of any evidence of other major shocks for at least 1.3 ka prior to 1811 and possibly for >9 ka. Stratigraphic relations and radiocarbon dating at a recently excavated archaeological site near East Prairie, Missouri, have revealed liquifaction phenomena attributable to a shock dated to within about 100 yr prior to A.D. 539 and a probablemore » second one dated between about A.D. 539 and 991.« less

  5. Radiosonde observational evidence of the influence of extreme SST gradient upon atmospheric meso-scale circulation

    NASA Astrophysics Data System (ADS)

    Nishikawa, H.; Tachibana, Y.; Udagawa, Y.

    2012-12-01

    Although the influence of the anomalous midlatitude SST upon atmospheric local circulation has been getting common in particular over the Kuroshio and the Gulf Stream regions, observational studies on the influence of the Okhotsk Sea, which is to the north of the Kuroshio, upon the atmospheric local circulation is much less than those of the Kuroshio. The climate of the Okhotsk SST is very peculiar. Extremely cold SST spots, whose summertime SST is lower than 5 Celsius degrees, are formed around Kuril Islands. Because SSTs are generally determined by local air-sea interaction as well as temperature advection, it is very difficult to isolate only the oceanic influence upon the atmosphere. The SST in this cold spot is, however, dominated by the tidal mixing, which is independent of the atmospheric processes. This unique condition may ease the account for the oceanic influence only. Although the SST environment of the Okhotsk Sea is good for understanding the oceanic influence upon the atmosphere, only a few studies has been executed in this region because of the difficulty of observations by research vessels in this region, where territory problems between Japan and Russia is unsolved. Because of the scant of direct observation, the Okhotsk Sea was still mysterious. In 2006 August, GPS radiosonde observation was carried out by Russian research vessel Khromov in the Sea of Okhotsk by the cooperation between Japan and Russia, and strong SST gradient of about 7 Celsius degrees/10km was observed around the Kuril Islands. The purpose of this study is to demonstrate observational finding of meso-scale atmospheric anticyclonic circulation influenced by the cold oceanic spot around the Kuril Island. The summaries of the observation are as follows. Meso-scale atmospheric ageostrophic anticyclonic circulation in the atmospheric marine-boundary layer is observed in and around the cold spot. A high air pressure area as compared with other surrounding areas is also located at the

  6. FOXP2 Targets Show Evidence of Positive Selection in European Populations

    PubMed Central

    Ayub, Qasim; Yngvadottir, Bryndis; Chen, Yuan; Xue, Yali; Hu, Min; Vernes, Sonja C.; Fisher, Simon E.; Tyler-Smith, Chris

    2013-01-01

    Forkhead box P2 (FOXP2) is a highly conserved transcription factor that has been implicated in human speech and language disorders and plays important roles in the plasticity of the developing brain. The pattern of nucleotide polymorphisms in FOXP2 in modern populations suggests that it has been the target of positive (Darwinian) selection during recent human evolution. In our study, we searched for evidence of selection that might have followed FOXP2 adaptations in modern humans. We examined whether or not putative FOXP2 targets identified by chromatin-immunoprecipitation genomic screening show evidence of positive selection. We developed an algorithm that, for any given gene list, systematically generates matched lists of control genes from the Ensembl database, collates summary statistics for three frequency-spectrum-based neutrality tests from the low-coverage resequencing data of the 1000 Genomes Project, and determines whether these statistics are significantly different between the given gene targets and the set of controls. Overall, there was strong evidence of selection of FOXP2 targets in Europeans, but not in the Han Chinese, Japanese, or Yoruba populations. Significant outliers included several genes linked to cellular movement, reproduction, development, and immune cell trafficking, and 13 of these constituted a significant network associated with cardiac arteriopathy. Strong signals of selection were observed for CNTNAP2 and RBFOX1, key neurally expressed genes that have been consistently identified as direct FOXP2 targets in multiple studies and that have themselves been associated with neurodevelopmental disorders involving language dysfunction. PMID:23602712

  7. Strong negative terahertz photoconductivity in photoexcited graphene

    NASA Astrophysics Data System (ADS)

    Fu, Maixia; Wang, Xinke; Ye, Jiasheng; Feng, Shengfei; Sun, Wenfeng; Han, Peng; Zhang, Yan

    2018-01-01

    Terahertz (THz) response of a chemical vapor deposited graphene on a quartz substrate has been investigated by using an ultrafast optical-pump THz-probe spectroscopy. Without photoexcitation, the frequency-dependence optical conductivity shows a strong carrier response owing to the intrinsically doped graphene. Upon photoexcitation, an enhancement in THz transmission is observed and the transmission increases nonlinearly with the increase of pump power, which is rooted in a reduction of intrinsic conductivity arising from the strong enhancement of carrier scattering rather than THz emission occurrence. The modulation depth of 18.8% was experimentally achieved, which is more than four times greater than that of the previous reported. The photoinduced response here highlights the variety of response possible in graphene depending on the sample quality, carrier mobility and doping level. The graphene provides promising applications in high-performance THz modulators and THz photoelectric devices.

  8. Cavity Quantum Acoustic Device in the Multimode Strong Coupling Regime.

    PubMed

    Moores, Bradley A; Sletten, Lucas R; Viennot, Jeremie J; Lehnert, K W

    2018-06-01

    We demonstrate an acoustical analog of a circuit quantum electrodynamics system that leverages acoustic properties to enable strong multimode coupling in the dispersive regime while suppressing spontaneous emission to unconfined modes. Specifically, we fabricate and characterize a device that comprises a flux tunable transmon coupled to a 300  μm long surface acoustic wave resonator. For some modes, the qubit-cavity coupling reaches 6.5 MHz, exceeding the cavity loss rate (200 kHz), qubit linewidth (1.1 MHz), and the cavity free spectral range (4.8 MHz), placing the device in both the strong coupling and strong multimode regimes. With the qubit detuned from the confined modes of the cavity, we observe that the qubit linewidth strongly depends on its frequency, as expected for spontaneous emission of phonons, and we identify operating frequencies where this emission rate is suppressed.

  9. On Multiple Reconnection X-lines and Tripolar Perturbations of Strong Guide Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Eriksson, S.; Lapenta, G.; Newman, D. L.; Phan, T. D.; Gosling, J. T.; Lavraud, B.; Khotyaintsev, Yu. V.; Carr, C. M.; Markidis, S.; Goldman, M. V.

    2015-05-01

    We report new multi-spacecraft Cluster observations of tripolar guide magnetic field perturbations at a solar wind reconnection exhaust in the presence of a guide field BM which is almost four times as strong as the reversing field BL. The novel tripolar field consists of two narrow regions of depressed BM, with an observed 7%-14% ΔBM magnitude relative to the external field, which are found adjacent to a wide region of enhanced BM within the exhaust. A stronger reversing field is associated with each BM depression. A kinetic reconnection simulation for realistic solar wind conditions and the observed strong guide field reveals that tripolar magnetic fields preferentially form across current sheets in the presence of multiple X-lines as magnetic islands approach one another and merge into fewer and larger islands. The simulated ΔBM/ΔXN over the normal width ΔXN between a BM minimum and the edge of the external region agree with the normalized values observed by Cluster. We propose that a tripolar guide field perturbation may be used to identify candidate regions containing multiple X-lines and interacting magnetic islands at individual solar wind current sheets with a strong guide field.

  10. On Strong Anticipation

    PubMed Central

    Stepp, N.; Turvey, M. T.

    2009-01-01

    We examine Dubois's (2003) distinction between weak anticipation and strong anticipation. Anticipation is weak if it arises from a model of the system via internal simulations. Anticipation is strong if it arises from the system itself via lawful regularities embedded in the system's ordinary mode of functioning. The assumption of weak anticipation dominates cognitive science and neuroscience and in particular the study of perception and action. The assumption of strong anticipation, however, seems to be required by anticipation's ubiquity. It is, for example, characteristic of homeostatic processes at the level of the organism, organs, and cells. We develop the formal distinction between strong and weak anticipation by elaboration of anticipating synchronization, a phenomenon arising from time delays in appropriately coupled dynamical systems. The elaboration is conducted in respect to (a) strictly physical systems, (b) the defining features of circadian rhythms, often viewed as paradigmatic of biological behavior based in internal models, (c) Pavlovian learning, and (d) forward models in motor control. We identify the common thread of strongly anticipatory systems and argue for its significance in furthering understanding of notions such as “internal”, “model” and “prediction”. PMID:20191086

  11. Strongly correlated fermions after a quantum quench.

    PubMed

    Manmana, S R; Wessel, S; Noack, R M; Muramatsu, A

    2007-05-25

    Using the adaptive time-dependent density-matrix renormalization group method, we study the time evolution of strongly correlated spinless fermions on a one-dimensional lattice after a sudden change of the interaction strength. For certain parameter values, two different initial states (e.g., metallic and insulating) lead to observables which become indistinguishable after relaxation. We find that the resulting quasistationary state is nonthermal. This result holds for both integrable and nonintegrable variants of the system.

  12. Magnetospheric Multiscale Observations of Magnetic Reconnection Associated with Kelvin-Helmholtz Waves

    NASA Technical Reports Server (NTRS)

    Eriksson, S.; Lavraud, B.; Wilder, F. D.; Stawarz, J. E.; Giles, B. L.; Burch, J. L.; Baumjohann, W.; Ergun, R. E.; Lindqvist, P.-A.; Magnes, W.; hide

    2016-01-01

    The four Magnetospheric Multiscale (MMS) spacecraft recorded the first direct evidence of reconnection exhausts associated with Kelvln-Helmholtz (KH) waves at the duskside magnetopause on 8 September 2015 which allows for local mass and energy transport across the flank magnetopause. Pressure anisotropy-weighted Walen analyses confirmed in-plane exhausts across 22 of 42 KH-related trailing magnetopause current sheets (CSs). Twenty-one jets were observed by all spacecraft, with small variations in ion velocity, along the same sunward or antisunward direction with nearly equal probability. One exhaust was only observed by the MMS-1,2 pair, while MMS-3,4 traversed a narrow CS (1.5 ion inertial length) in the vicinity of an electron diffusion region. The exhausts were locally 2-D planar in nature as MMS-1, 2 observed almost identical signatures separated along the guide-field. Asymmetric magnetic and electric Hall fields are reported in agreement with a strong guide-field and a weak plasma density asymmetry across the magnetopause CS.

  13. Evidence for solar wind origin of energetic heavy ions in the earth's radiation belt

    NASA Technical Reports Server (NTRS)

    Hovestadt, D.; Klecker, B.; Scholer, M.; Gloeckler, G.; Ipavich, F. M.; Fan, C. Y.; Fisk, L. A.; Ogallagher, J. J.

    1978-01-01

    Analysis of data from our energetic ion composition experiment on ISEE-1 has revealed the presence of substantial fluxes of carbon, oxygen, and heavier ions above 400 keV/nucleon at L values between approximately 2.5 and 4 earth radii. The measured C/O ratio varies systematically from 1.3 at 450 keV/nucleon to 4.1 at 1.3 MeV/nucleon, and no iron is observed above 200 keV/nucleon. These results provide strong evidence for a solar wind origin for energetic ions in the outer radiation belt. The absence of iron and the increase of the carbon-to-oxygen ratio with energy suggest that the condition for the validity of the first adiabatic invariant may have a strong influence on the trapping of these particles.

  14. Strong field gravitational lensing by a charged Galileon black hole

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhao, Shan-Shan; Xie, Yi, E-mail: clefairy035@163.com, E-mail: yixie@nju.edu.cn

    Strong field gravitational lensings are dramatically disparate from those in the weak field by representing relativistic images due to light winds one to infinity loops around a lens before escaping. We study such a lensing caused by a charged Galileon black hole, which is expected to have possibility to evade no-hair theorem. We calculate the angular separations and time delays between different relativistic images of the charged Galileon black hole. All these observables can potentially be used to discriminate a charged Galileon black hole from others. We estimate the magnitudes of these observables for the closest supermassive black hole Sgrmore » A*. The strong field lensing observables of the charged Galileon black hole can be close to those of a tidal Reissner-Nordström black hole or those of a Reissner-Nordström black hole. It will be helpful to distinguish these black holes if we can separate the outermost relativistic images and determine their angular separation, brightness difference and time delay, although it requires techniques beyond the current limit.« less

  15. UP TO 100,000 RELIABLE STRONG GRAVITATIONAL LENSES IN FUTURE DARK ENERGY EXPERIMENTS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Serjeant, S.

    2014-09-20

    The Euclid space telescope will observe ∼10{sup 5} strong galaxy-galaxy gravitational lens events in its wide field imaging survey over around half the sky, but identifying the gravitational lenses from their observed morphologies requires solving the difficult problem of reliably separating the lensed sources from contaminant populations, such as tidal tails, as well as presenting challenges for spectroscopic follow-up redshift campaigns. Here I present alternative selection techniques for strong gravitational lenses in both Euclid and the Square Kilometre Array, exploiting the strong magnification bias present in the steep end of the Hα luminosity function and the H I mass function.more » Around 10{sup 3} strong lensing events are detectable with this method in the Euclid wide survey. While only ∼1% of the total haul of Euclid lenses, this sample has ∼100% reliability, known source redshifts, high signal-to-noise, and a magnification-based selection independent of assumptions of lens morphology. With the proposed Square Kilometre Array dark energy survey, the numbers of reliable strong gravitational lenses with source redshifts can reach 10{sup 5}.« less

  16. 90 GHz Observations of M87 and Hydra A

    NASA Technical Reports Server (NTRS)

    Cotton, W. D.; Mason, B. S.; Dicker, S. R.; Korngut, P. M.; Devlin, M. J.; Aquirre, J.; Benford, D. J.; Moseley, S. H.; Staguhn, J. G.; Irwin, K. D.; hide

    2009-01-01

    This paper presents new observations of the active galactic nuclei M87 and Hydra A at 90 GHz made with the MUSTANG array on the Green Bank Telescope at 8"5 resolution. A spectral analysis is performed combining this new data and archival VLA 7 data on these objects at longer wavelengths. This analysis can detect variations in spectral index and curvature expected from energy losses in the radiating particles. M87 shows only weak evidence for steepening of the spectrum along the jet suggesting either re-acceleration of the relativistic particles in the jet or insufficient losses to affect the spectrum at 90 GHz. The jets in Hydra A show strong steepening as they move from the nucleus suggesting unbalanced losses of the higher energy relativistic particles. The difference between these two sources may be accounted for by the lengths over which the jets are observable, 2 kpc for M87 and 45 kpc for Hydra A.

  17. EGRET/COMPTEL Observations of an Unusual, Steep-Spectrum Gamma-Ray Source

    NASA Technical Reports Server (NTRS)

    Thompson, D. J.; Bertsch, D. L.; Hartman, R. C.; Collmar, W.; Johnson, W. N.

    1999-01-01

    During analysis of sources below the threshold of the third EGRET catalog, we have discovered a source, named GRO J1400-3956 based on the best position, with a remarkably steep spectrum. Archival analysis of COMPTEL data shows that the spectrum must have a strong turn-over in the energy range between COMPTEL and EGRET. The EGRET data show some evidence of time variability, suggesting an AGN, but the spectral change of slope is larger than that seen for most gamma-ray blazars. The sharp cutoff resembles the high-energy spectral breaks seen in some gamma-ray pulsars. There have as yet been no OSSE observations of this source.

  18. Triggering Descending Pain Inhibition by Observing Ourselves or a Loved-One in Pain.

    PubMed

    Gougeon, Véronique; Gaumond, Isabelle; Goffaux, Philippe; Potvin, Stéphane; Marchand, Serge

    2016-03-01

    Recent studies demonstrate that empathy-evoked brain responses include the activation of brainstem structures responsible for triggering descending pain inhibition. Unfortunately, direct evidence linking empathy for pain and descending inhibitory controls (conditioned pain modulation) is lacking. This study, therefore, aimed to determine if the observation of ourselves or a loved-one in pain could activate descending pain inhibition without exposure to a noxious stimulation; which is otherwise required. Descending pain inhibition was triggered by immersing the right arm of participants (15 heterosexual couples; mean age±SE: 28.89±2.14) in a bath of cold water. The effects of empathy on descending pain inhibition were observed by immersing the right arm of participants in a bath of lukewarm water while having them watch a video of either themselves or their spouse during a previous nociceptive immersion. Immersion of the arm in a bath of lukewarm water without empathic (video) observation was also included as a control condition. A strong inhibitory response activated by the mere observation of the video of themselves or their spouse in pain without a nociceptive conditioning stimulus. Associative statistics also showed that strong pain catastrophizing responses while watching the video resulted in stronger pain inhibition. Moreover, high levels of empathy were associated with stronger pain inhibition, but only for women. This study showed that observing someone in pain triggers descending pain inhibition. Results also demonstrate how empathy and gender are affecting pain modulation mechanisms.

  19. Strong Purifying Selection at Synonymous Sites in D. melanogaster

    PubMed Central

    Lawrie, David S.; Messer, Philipp W.; Hershberg, Ruth; Petrov, Dmitri A.

    2013-01-01

    Synonymous sites are generally assumed to be subject to weak selective constraint. For this reason, they are often neglected as a possible source of important functional variation. We use site frequency spectra from deep population sequencing data to show that, contrary to this expectation, 22% of four-fold synonymous (4D) sites in Drosophila melanogaster evolve under very strong selective constraint while few, if any, appear to be under weak constraint. Linking polymorphism with divergence data, we further find that the fraction of synonymous sites exposed to strong purifying selection is higher for those positions that show slower evolution on the Drosophila phylogeny. The function underlying the inferred strong constraint appears to be separate from splicing enhancers, nucleosome positioning, and the translational optimization generating canonical codon bias. The fraction of synonymous sites under strong constraint within a gene correlates well with gene expression, particularly in the mid-late embryo, pupae, and adult developmental stages. Genes enriched in strongly constrained synonymous sites tend to be particularly functionally important and are often involved in key developmental pathways. Given that the observed widespread constraint acting on synonymous sites is likely not limited to Drosophila, the role of synonymous sites in genetic disease and adaptation should be reevaluated. PMID:23737754

  20. Observation of the avalanche of runaway electrons in air in a strong electric field.

    PubMed

    Gurevich, A V; Mesyats, G A; Zybin, K P; Yalandin, M I; Reutova, A G; Shpak, V G; Shunailov, S A

    2012-08-24

    The generation of an avalanche of runaway electrons is demonstrated for the first time in a laboratory experiment. Two flows of runaway electrons are formed sequentially in an extended air discharge gap at the stage of delay of a pulsed breakdown. The first, picosecond, runaway electron flow is emitted in the cathode region where the field is enhanced. Being accelerated in the gap, this beam generates electrons due to impact ionization. These secondary electrons form a delayed avalanche of runaway electrons if the field is strong enough. The properties of the avalanche correspond to the existing notions about the runaway breakdown in air. The measured current of the avalanche exceeds up to an order the current of the initiating electron beam.

  1. Observation of the Avalanche of Runaway Electrons in Air in a Strong Electric Field

    NASA Astrophysics Data System (ADS)

    Gurevich, A. V.; Mesyats, G. A.; Zybin, K. P.; Yalandin, M. I.; Reutova, A. G.; Shpak, V. G.; Shunailov, S. A.

    2012-08-01

    The generation of an avalanche of runaway electrons is demonstrated for the first time in a laboratory experiment. Two flows of runaway electrons are formed sequentially in an extended air discharge gap at the stage of delay of a pulsed breakdown. The first, picosecond, runaway electron flow is emitted in the cathode region where the field is enhanced. Being accelerated in the gap, this beam generates electrons due to impact ionization. These secondary electrons form a delayed avalanche of runaway electrons if the field is strong enough. The properties of the avalanche correspond to the existing notions about the runaway breakdown in air. The measured current of the avalanche exceeds up to an order the current of the initiating electron beam.

  2. 77 FR 53212 - Notice of Proposed Information Collection: Comment Request Strong Cities Strong Communities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-31

    ... Information Collection: Comment Request Strong Cities Strong Communities National Resource Network AGENCY... National Resource Network. OMB Control Number, if applicable: 2528--Pending. Description of the need for... information related to the proposed Strong Cities Strong Communities National Resource Network. The U.S...

  3. ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Bin; Maddumage, Prasad; Kantowski, Ronald

    2015-05-15

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravitymore » field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.« less

  4. Algorithms and Programs for Strong Gravitational Lensing In Kerr Space-time Including Polarization

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie; Maddumage, Prasad

    2015-05-01

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.

  5. Zero Pearson coefficient for strongly correlated growing trees

    NASA Astrophysics Data System (ADS)

    Dorogovtsev, S. N.; Ferreira, A. L.; Goltsev, A. V.; Mendes, J. F. F.

    2010-03-01

    We obtained Pearson’s coefficient of strongly correlated recursive networks growing by preferential attachment of every new vertex by m edges. We found that the Pearson coefficient is exactly zero in the infinite network limit for the recursive trees (m=1) . If the number of connections of new vertices exceeds one (m>1) , then the Pearson coefficient in the infinite networks equals zero only when the degree distribution exponent γ does not exceed 4. We calculated the Pearson coefficient for finite networks and observed a slow power-law-like approach to an infinite network limit. Our findings indicate that Pearson’s coefficient strongly depends on size and details of networks, which makes this characteristic virtually useless for quantitative comparison of different networks.

  6. Zero Pearson coefficient for strongly correlated growing trees.

    PubMed

    Dorogovtsev, S N; Ferreira, A L; Goltsev, A V; Mendes, J F F

    2010-03-01

    We obtained Pearson's coefficient of strongly correlated recursive networks growing by preferential attachment of every new vertex by m edges. We found that the Pearson coefficient is exactly zero in the infinite network limit for the recursive trees (m=1). If the number of connections of new vertices exceeds one (m>1), then the Pearson coefficient in the infinite networks equals zero only when the degree distribution exponent gamma does not exceed 4. We calculated the Pearson coefficient for finite networks and observed a slow power-law-like approach to an infinite network limit. Our findings indicate that Pearson's coefficient strongly depends on size and details of networks, which makes this characteristic virtually useless for quantitative comparison of different networks.

  7. Thermal structure and minor species distribution of Venus mesosphere by ALMA submm observations

    NASA Astrophysics Data System (ADS)

    Piccialli, Arianna; Moreno, Raphael; Encrenaz, Therese; Fouchet, Thierry; Lellouch, Emmanuel; Moullet, Arielle; Widemann, Thomas

    2015-11-01

    Venus upper atmosphere (70-150 km altitude) is a transition region characterized by a complex dynamics: strong retrograde zonal winds dominate the lower mesosphere while a solar-to-antisolar circulation is observed in the upper mesosphere/lower thermosphere. In addition, photochemical processes play an important role at these altitudes and affect the thermal structure and chemical stability of the entire atmosphere. Sulfur dioxide and water vapor are key species in the photochemical cycles taking place in the troposphere and mesosphere of Venus. They are carried by convective transport, together with the Hadley circulation, up to about 60 km where SO2 is photodissociated and oxydated, leading to the formation of H2SO4 which condenses in the clouds enshrouding the planet. Previous observations obtained by several instruments on board Venus Express and during ground-based campaigns have shown evidence of strong temporal variations, both on day-to-day as well as longer timescales, of density, temperature and SO2 abundance. Such strong variability is still not well understood.Submillimeter observations obtained with the Atacama Large Millimeter Array (ALMA) offer the possibility of probing Venus upper mesosphere and of monitoring minor species, winds and the thermal structure. A first set of observations was obtained on November 14, 15, 26 and 27, 2011 during the first ALMA Early Science observation cycle. These observations targeted SO2, SO, HDO and CO transitions around 345 GHz during four sequences of 30 minutes each. The Venus’ disk was about 11” with an illumination factor of 90%, so that mostly the dayside of the planet was mapped.Assuming nominal night-time and dayside CO abundance profiles from Clancy et al. 2013, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time for the four days of observation. Temperature profiles were later used to derive the abundances of minor species (HDO, SO, SO2) in each pixel

  8. On the discrepancy between eddy covariance and lysimetry-based surface flux measurements under strongly advective conditions

    NASA Astrophysics Data System (ADS)

    Alfieri, Joseph G.; Kustas, William P.; Prueger, John H.; Hipps, Lawrence E.; Evett, Steven R.; Basara, Jeffrey B.; Neale, Christopher M. U.; French, Andrew N.; Colaizzi, Paul; Agam, Nurit; Cosh, Michael H.; Chavez, José L.; Howell, Terry A.

    2012-12-01

    Discrepancies can arise among surface flux measurements collected using disparate techniques due to differences in both the instrumentation and theoretical underpinnings of the different measurement methods. Using data collected primarily within a pair of irrigated cotton fields as a part of the 2008 Bushland Evapotranspiration and Remote Sensing Experiment (BEAREX08), flux measurements collected with two commonly-used methods, eddy covariance (EC) and lysimetry (LY), were compared and substantial differences were found. Daytime mean differences in the flux measurements from the two techniques could be in excess of 200 W m-2 under strongly advective conditions. Three causes for this disparity were found: (i) the failure of the eddy covariance systems to fully balance the surface energy budget, (ii) flux divergence due to the local advection of warm, dry air over the irrigated cotton fields, and (iii) the failure of lysimeters to accurately represent the surface properties of the cotton fields as a whole. Regardless of the underlying cause, the discrepancy among the flux measurements underscores the difficulty in collecting these measurements under strongly advective conditions. It also raises awareness of the uncertainty associated with in situ micrometeorological measurements and the need for caution when using such data for model validation or as observational evidence to definitively support or refute scientific hypotheses.

  9. Strongly-motivated positive affects induce faster responses to local than global information of visual stimuli: an approach using large-size Navon letters.

    PubMed

    Noguchi, Yasuki; Tomoike, Kouta

    2016-01-12

    Recent studies argue that strongly-motivated positive emotions (e.g. desire) narrow a scope of attention. This argument is mainly based on an observation that, while humans normally respond faster to global than local information of a visual stimulus (global advantage), positive affects eliminated the global advantage by selectively speeding responses to local (but not global) information. In other words, narrowing of attentional scope was indirectly evidenced by the elimination of global advantage (the same speed of processing between global and local information). No study has directly shown that strongly-motivated positive affects induce faster responses to local than global information while excluding a bias for global information (global advantage) in a baseline (emotionally-neutral) condition. In the present study, we addressed this issue by eliminating the global advantage in a baseline (neutral) state. Induction of positive affects under this state resulted in faster responses to local than global information. Our results provided direct evidence that positive affects in high motivational intensity narrow a scope of attention.

  10. Outcomes of Stay Strong, Stay Healthy in community settings.

    PubMed

    Ball, Stephen; Gammon, Robin; Kelly, Patricia J; Cheng, An-Lin; Chertoff, Keyna; Kaume, Lydia; Abreu, Eduardo L; Brotto, Marco

    2013-12-01

    Loss of muscle strength, flexibility, and balance are strong predictors of falls in the elderly. The goal of this research was to investigate the effectiveness of a 10-week, strength-based exercise program delivered by Extension professionals. Matched pair t tests were used to compare differences in five measures of fitness collected from 808 participants (mean age = 65.4 years) at the start and finish of the exercise program. Following programming, participants significantly improved strength, flexibility, and balance. Results indicate that an evidence-based program can be translated into a community Extension program that is able to improve the fitness level of seniors.

  11. Endoscopic management of acute necrotizing pancreatitis: European Society of Gastrointestinal Endoscopy (ESGE) evidence-based multidisciplinary guidelines.

    PubMed

    Arvanitakis, Marianna; Dumonceau, Jean-Marc; Albert, Jörg; Badaoui, Abdenor; Bali, Maria Antonietta; Barthet, Marc; Besselink, Marc; Deviere, Jacques; Oliveira Ferreira, Alexandre; Gyökeres, Tibor; Hritz, Istvan; Hucl, Tomas; Milashka, Marianna; Papanikolaou, Ioannis S; Poley, Jan-Werner; Seewald, Stefan; Vanbiervliet, Geoffroy; van Lienden, Krijn; van Santvoort, Hjalmar; Voermans, Rogier; Delhaye, Myriam; van Hooft, Jeanin

    2018-05-01

    1:  ESGE suggests using contrast-enhanced computed tomography (CT) as the first-line imaging modality on admission when indicated and up to the 4th week from onset in the absence of contraindications. Magnetic resonance imaging (MRI) may be used instead of CT in patients with contraindications to contrast-enhanced CT, and after the 4th week from onset when invasive intervention is considered because the contents (liquid vs. solid) of pancreatic collections are better characterized by MRI and evaluation of pancreatic duct integrity is possible. Weak recommendation, low quality evidence. 2:  ESGE recommends against routine percutaneous fine needle aspiration (FNA) of (peri)pancreatic collections. Strong recommendation, moderate quality evidence. FNA should be performed only if there is suspicion of infection and clinical/imaging signs are unclear. Weak recommendation, low quality evidence. 3:  ESGE recommends initial goal-directed intravenous fluid therapy with Ringer's lactate (e. g. 5 - 10 mL/kg/h) at onset. Fluid requirements should be patient-tailored and reassessed at frequent intervals. Strong recommendation, moderate quality evidence. 4:  ESGE recommends against antibiotic or probiotic prophylaxis of infectious complications in acute necrotizing pancreatitis. Strong recommendation, high quality evidence. 5:  ESGE recommends invasive intervention for patients with acute necrotizing pancreatitis and clinically suspected or proven infected necrosis. Strong recommendation, low quality evidence.ESGE suggests that the first intervention for infected necrosis should be delayed for 4 weeks if tolerated by the patient. Weak recommendation, low quality evidence. 6:  ESGE recommends performing endoscopic or percutaneous drainage of (suspected) infected walled-off necrosis as the first interventional method, taking into account the location of the walled-off necrosis and local expertise. Strong recommendation, moderate quality evidence. 7:

  12. Deteriorating water clarity in shallow waters: Evidence from long term MODIS and in-situ observations

    NASA Astrophysics Data System (ADS)

    Shi, Kun; Zhang, Yunlin; Zhu, Guangwei; Qin, Boqiang; Pan, Delu

    2018-06-01

    Water clarity (Secchi disk depth: SDD), as a proxy of water transparency, provides important information on the light availability to the water or lake ecosystem. Shallow lakes have been experienced dramatic environmental and climatic change. This study demonstrated using combination of long-term MODIS and in-situ measurements to track the dynamics of SDD with these environmental and climate changes in shallow water environments. We selected a typical turbid shallow Lake Taihu as our case study. Based on MODIS-Aqua data, an empirical model for estimating SDD was developed and validated. Subsequently, we employed the proposed model to derive the spatial and temporal SDD distribution patterns of Lake Taihu from 2003 to 2015. Combining MODIS-derived SDD time series of 2003-2015 and long-term in-situ SDD observations dated back to 1993, we elucidated SDD long-term variation trends and driving mechanism. Deteriorating water clarity from the long-term SDD observations indicated that Lake Taihu became more and more turbid and water quality was decreasing. Increasing in cyanobacterial bloom area, as a result of decreasing in wind speed and eutrophication, may partially be responsible for the decreasing trend. A predicted future decrease in the wind speed in Lake Taihu region could enhance the formation of cyanobacterial blooms and consequently lead to a further decrease in water clarity. This study suggested that coupling remote sensing monitoring and long-term in-situ observations could provide robust evidence and new insights to elucidate long-term dynamics in aquatic ecosystem evolution.

  13. FAST satellite observations of large-amplitude solitary structures

    NASA Astrophysics Data System (ADS)

    Ergun, R. E.; Carlson, C. W.; McFadden, J. P.; Mozer, F. S.; Delory, G. T.; Peria, W.; Chaston, C. C.; Temerin, M.; Roth, I.; Muschietti, L.; Elphic, R.; Strangeway, R.; Pfaff, R.; Cattell, C. A.; Klumpar, D.; Shelley, E.; Peterson, W.; Moebius, E.; Kistler, L.

    We report observations of “fast solitary waves” that are ubiquitous in downward current regions of the mid-altitude auroral zone. The single-period structures have large amplitudes (up to 2.5 V/m), travel much faster than the ion acoustic speed, carry substantial potentials (up to ∼100 Volts), and are associated with strong modulations of energetic electron fluxes. The amplitude and speed of the structures distinguishes them from ion-acoustic solitary waves or weak double layers. The electromagnetic signature appears to be that of an positive charge (electron hole) traveling anti-earthward. We present evidence that the structures are in or near regions of magnetic-field-aligned electric fields and propose that these nonlinear structures play a key role in supporting parallel electric fields in the downward current region of the auroral zone.

  14. Restricted mating dispersal and strong breeding group structure in a mid-sized marsupial mammal (Petrogale penicillata).

    PubMed

    Hazlitt, S L; Sigg, D P; Eldridge, M D B; Goldizen, A W

    2006-09-01

    Ecological genetic studies have demonstrated that spatial patterns of mating dispersal, the dispersal of gametes through mating behaviour, can facilitate inbreeding avoidance and strongly influence the structure of populations, particularly in highly philopatric species. Elements of breeding group dynamics, such as strong structuring and sex-biased dispersal among groups, can also minimize inbreeding and positively influence levels of genetic diversity within populations. Rock-wallabies are highly philopatric mid-sized mammals whose strong dependence on rocky terrain has resulted in series of discreet, small colonies in the landscape. Populations show no signs of inbreeding and maintain high levels of genetic diversity despite strong patterns of limited gene flow within and among colonies. We used this species to investigate the importance of mating dispersal and breeding group structure to inbreeding avoidance within a 'small' population. We examined the spatial patterns of mating dispersal, the extent of kinship within breeding groups, and the degree of relatedness among brush-tailed rock-wallaby breeding pairs within a colony in southeast Queensland. Parentage data revealed remarkably restricted mating dispersal and strong breeding group structuring for a mid-sized mammal. Breeding groups showed significant levels of female kinship with evidence of male dispersal among groups. We found no evidence for inbreeding avoidance through mate choice; however, anecdotal data suggest the importance of life history traits to inbreeding avoidance between first-degree relatives. We suggest that the restricted pattern of mating dispersal and strong breeding group structuring facilitates inbreeding avoidance within colonies. These results provide insight into the population structure and maintenance of genetic diversity within colonies of the threatened brush-tailed rock-wallaby.

  15. Evidence of 3-D Reconnection at Null Point from the Observations of Circular Flares and Homologous Jets

    NASA Astrophysics Data System (ADS)

    Wang, Haimin; Liu, C.

    2012-05-01

    In recent studies by Pariat, Antiochos and DeVore (2009, 2010), fan-separatrix topology and magnetic reconnection at the null-point were simulated and found to produce homologous jets. This motivates us to search for axisymmetric magnetic structure and associated flaring/jetting activity. Using high-resolution ( 0.15" per pixel) and high-cadence ( 15 s) H-alpha center/offband observations obtained from the recently digitized films of Big Bear Solar Observatory, we were able to identify five large circular flares with associated surges. All the events exhibit a central parasite magnetic field surrounded by opposite polarity, forming a circular polarity inversion line (PIL). Consequently, a compact flare kernel at the center is surrounded by a circular ribbon, and together with the upward ejecting dark surge, these seem to depict a dome-like magnetic structure. Very interestingly, (1) the circular ribbon brightens sequentially rather than simultaneously, (2) the central compact flare kernel shows obvious motion, and (3) a remote elongated, co-temporal flare ribbon at a region with the same polarity as the central parasite site is seen in the series of four homologous events on 1991 March 17 and 18. The remote ribbon is 120" away from the jet location. Moreover, magnetic reconnection across the circular PIL is evident from the magnetic flux cancellation. These rarely observed homologous surges with circular as well as central and remote flare ribbons provide valuable evidence concerning the dynamics of magnetic reconnection in a null-point topology. This study is dedicated to Professor Hal Zirin, the founder of Big Bear Solar Observatory, who passed away on January 3, 2012.

  16. Observational and numerical evidence for ocean frontogenesis inducing submesoscale processes and impacting biochemistry

    NASA Astrophysics Data System (ADS)

    Claret, M.; Ruiz, S.; Pascual, A.; Olita, A.; Mahadevan, A.; Tovar, A.; Troupin, C.; Tintore, J.; Capet, A.

    2016-02-01

    We present the results of ALBOREX, a multi-platform and multi-disciplinary experiment completed in May 2014 as a part of PERSEUS EU funded project. This unique process-oriented experiment in the eastern Alboran Sea (Western Mediterranean) examined mesoscale and submesoscale dynamics at an intense front. The field campaign, conducted during 8 days, included 25 drifters, 2 gliders, 3 Argo floats and one ship (66 CTDs and 500 biochemical samples). The drifters followed coherently an anticyclonic gyre. ADCP data showed consistent patterns with currents up to 1 m/s in the southern part of the domain and Rossby numbers up to 1.5 suggesting significant ageostrophic motion. We show observational evidence for mesoscale frontogenesis produced by the confluence of (fresh) Atlantic Water and the resident (more saline) Mediterranean Water. This confluence resulted in lateral density gradients of the order of 1 kg/m3 in 10 km and associated vertical velocities of about ±20 m/day, diagnosed using the QG Omega equation. However, the vertical velocity is likely underestimated due to unresolved submesoscale processes (<10 km), which are induced by intense mesoscale frontogenesis. In order to assess the role of these submesoscale processes in the frontal vertical transport, a high-resolution Process Ocean Model Study is initialized with hydrographic data (0.5-1 km resolution) from underwater gliders. Numerical results show that observed lateral buoyancy gradients are large enough to trigger submesoscale mixed layer instabilities. The coupling between mesoscale and submesoscale phenomena can explain remarkable subduction events of chlorophyll and oxygen captured by ocean gliders, as well as local increases of primary production.

  17. Association between dietary nitrate and nitrite intake and sitespecific cancer risk: evidence from observational studies.

    PubMed

    Xie, Li; Mo, Miao; Jia, Hui-Xun; Liang, Fei; Yuan, Jing; Zhu, Ji

    2016-08-30

    Epidemiological studies have reported inconsistent findings on the association between dietary nitrate and nitrite intake and cancer risk. We performed a meta-analysis of epidemiological studies to summarize available evidence on the association between dietary nitrate and nitrite intake and cancer risk from published prospective and case-control studies. PubMed database was searched to identify eligible publications through April 30th, 2016. Study-specific relative risks (RRs) with corresponding 95% confidence interval (CI) from individual studies were pooled by using random- or fixed- model, and heterogeneity and publication bias analyses were conducted. Data from 62 observational studies, 49 studies for nitrates and 51 studies for nitrites, including a total of 60,627 cancer cases were analyzed. Comparing the highest vs. lowest levels, dietary nitrate intake was inversely associated with gastric cancer risk (RR = 0.78; 95%CI = 0.67-0.91) with moderate heterogeneity (I2 = 42.3%). In contrast, dietary nitrite intake was positively associated with adult glioma and thyroid cancer risk with pooled RR of 1.21 (95%CI = 1.03-1.42) and 1.52 (95%CI = 1.12-2.05), respectively. No significant associations were found between dietary nitrate/nitrite and cancers of the breast, bladder, colorectal, esophagus, renal cell, non-Hodgkin lymphoma, ovarian, and pancreas. The present meta-analysis provided modest evidence that positive associations of dietary nitrate and negative associations of dietary nitrite with certain cancers.

  18. Experimental evidence that density dependence strongly influences plant invasions through fragmented landscapes.

    PubMed

    Williams, Jennifer L; Levine, Jonathan M

    2018-04-01

    Populations of range expanding species encounter patches of both favorable and unfavorable habitat as they spread across landscapes. Theory shows that increasing patchiness slows the spread of populations modeled with continuously varying population density when dispersal is not influence by the environment or individual behavior. However, as is found in uniformly favorable landscapes, spread remains driven by fecundity and dispersal from low density individuals at the invasion front. In contrast, when modeled populations are composed of discrete individuals, patchiness causes populations to build up to high density before dispersing past unsuitable habitat, introducing an important influence of density dependence on spread velocity. To test the hypothesized interaction between habitat patchiness and density dependence, we simultaneously manipulated these factors in a greenhouse system of annual plants spreading through replicated experimental landscapes. We found that increasing the size of gaps and amplifying the strength of density dependence both slowed spread velocity, but contrary to predictions, the effect of amplified density dependence was similar across all landscape types. Our results demonstrate that the discrete nature of individuals in spreading populations has a strong influence on how both landscape patchiness and density dependence influence spread through demographic and dispersal stochasticity. Both finiteness and landscape structure should be critical components to theoretical predictions of future spread for range expanding native species or invasive species colonizing new habitat. © 2018 by the Ecological Society of America.

  19. Optical investigation of the strong spin-orbit-coupled magnetic semimetal YbMnBi2

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Dipanjan; Cheng, Bing; Yaresko, Alexander; Gibson, Quinn D.; Cava, R. J.; Armitage, N. P.

    2017-08-01

    Strong spin-orbit coupling (SOC) can result in ground states with nontrivial topological properties. The situation is even richer in magnetic systems where the magnetic ordering can potentially have strong influence over the electronic band structure. The class of A MnBi2 (A = Sr, Ca) compounds are important in this context as they are known to host massive Dirac fermions with strongly anisotropic dispersion, which is believed to be due to the interplay between strong SOC and magnetic degrees of freedom. We report the optical conductivity of YbMnBi2, a newly discovered member of this family and a proposed Weyl semimetal (WSM) candidate with broken time reversal symmetry. Together with density functional theory (DFT) band-structure calculations, we show that the complex conductivity can be interpreted as the sum of an intraband Drude response and interband transitions. We argue that the canting of the magnetic moments that has been proposed to be essential for the realization of the WSM in an otherwise antiferromagnetically ordered system is not necessary to explain the optical conductivity. We believe our data is explained qualitatively by the uncanted magnetic structure with a small offset of the chemical potential from strict stochiometry. We find no definitive evidence of a bulk Weyl nodes. Instead, we see signatures of a gapped Dirac dispersion, common in other members of A MnBi2 family or compounds with similar 2D network of Bi atoms. We speculate that the evidence for a WSM seen in ARPES arises through a surface magnetic phase. Such an assumption reconciles all known experimental data.

  20. Evidence of Tropospheric 90 Day Oscillations in the Thermosphere

    NASA Astrophysics Data System (ADS)

    Gasperini, F.; Hagan, M. E.; Zhao, Y.

    2017-10-01

    In the last decade evidence demonstrated that terrestrial weather greatly impacts the dynamics and mean state of the thermosphere via small-scale gravity waves and global-scale solar tidal propagation and dissipation effects. While observations have shown significant intraseasonal variability in the upper mesospheric mean winds, relatively little is known about this variability at satellite altitudes (˜250-400 km). Using cross-track wind measurements from the Challenging Minisatellite Payload and Gravity field and steady-state Ocean Circulation Explorer satellites, winds from a Modern-Era Retrospective Analysis for Research and Applications/Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model simulation, and outgoing longwave radiation data, we demonstrate the existence of a prominent and global-scale 90 day oscillation in the thermospheric zonal mean winds and in the diurnal eastward propagating tide with zonal wave number 3 (DE3) during 2009-2010 and present evidence of its connection to variability in tropospheric convective activity. This study suggests that strong coupling between the troposphere and the thermosphere occurs on intraseasonal timescales.

  1. Quantifying the AGN-driven outflows in ULIRGs (QUADROS) II: evidence for compact outflow regions from HST [OIII] imaging observations

    NASA Astrophysics Data System (ADS)

    Tadhunter, C.; Zaurín, J. Rodríguez; Rose, M.; Spence, R. A. W.; Batcheldor, D.; Berg, M. A.; Ramos Almeida, C.; Spoon, H. W. W.; Sparks, W.; Chiaberge, M.

    2018-05-01

    The true importance of the warm, AGN-driven outflows for the evolution of galaxies remains uncertain. Measurements of the radial extents of the outflows are key for quantifying their masses and kinetic powers, and also establishing whether the AGN outflows are galaxy-wide. Therefore, as part of a larger project to investigate the significance of warm, AGN-driven outflows in the most rapidly evolving galaxies in the local universe, here we present deep Hubble Space Telescope (HST) narrow-band [OIII]λ5007 observations of a complete sample of 8 nearby ULIRGs with optical AGN nuclei. Combined with the complementary information provided by our ground-based spectroscopy, the HST images show that the warm gas outflows are relatively compact for most of the objects in the sample: in three objects the outflow regions are barely resolved at the resolution of HST (0.065 < R[OIII] < 0.12 kpc); in a further four cases the outflows are spatially resolved but with flux weighted mean radii in the range 0.65 < R[OIII] < 1.2 kpc; and in only one object (Mrk273) is there clear evidence for a more extended outflow, with a maximum extent of R[OIII] ˜ 5 kpc. Overall, our observations show little evidence for the galaxy-wide outflows predicted by some models of AGN feedback.

  2. Mendelian randomisation analysis strongly implicates adiposity with risk of developing colorectal cancer.

    PubMed

    Jarvis, David; Mitchell, Jonathan S; Law, Philip J; Palin, Kimmo; Tuupanen, Sari; Gylfe, Alexandra; Hänninen, Ulrika A; Cajuso, Tatiana; Tanskanen, Tomas; Kondelin, Johanna; Kaasinen, Eevi; Sarin, Antti-Pekka; Kaprio, Jaakko; Eriksson, Johan G; Rissanen, Harri; Knekt, Paul; Pukkala, Eero; Jousilahti, Pekka; Salomaa, Veikko; Ripatti, Samuli; Palotie, Aarno; Järvinen, Heikki; Renkonen-Sinisalo, Laura; Lepistö, Anna; Böhm, Jan; Meklin, Jukka-Pekka; Al-Tassan, Nada A; Palles, Claire; Martin, Lynn; Barclay, Ella; Farrington, Susan M; Timofeeva, Maria N; Meyer, Brian F; Wakil, Salma M; Campbell, Harry; Smith, Christopher G; Idziaszczyk, Shelley; Maughan, Timothy S; Kaplan, Richard; Kerr, Rachel; Kerr, David; Buchanan, Daniel D; Win, Aung K; Hopper, John L; Jenkins, Mark A; Lindor, Noralane M; Newcomb, Polly A; Gallinger, Steve; Conti, David; Schumacher, Fred; Casey, Graham; Taipale, Jussi; Aaltonen, Lauri A; Cheadle, Jeremy P; Dunlop, Malcolm G; Tomlinson, Ian P; Houlston, Richard S

    2016-07-12

    Observational studies have associated adiposity with an increased risk of colorectal cancer (CRC). However, such studies do not establish a causal relationship. To minimise bias from confounding we performed a Mendelian randomisation (MR) analysis to examine the relationship between adiposity and CRC. We used SNPs associated with adult body mass index (BMI), waist-hip ratio (WHR), childhood obesity and birth weight as instrumental variables in a MR analysis of 9254 CRC cases and 18 386 controls. In the MR analysis, the odds ratios (ORs) of CRC risk per unit increase in BMI, WHR and childhood obesity were 1.23 (95% CI: 1.02-1.49, P=0.033), 1.59 (95% CI: 1.08-2.34, P=0.019) and 1.07 (95% CI: 1.03-1.13, P=0.018), respectively. There was no evidence for association between birth weight and CRC (OR=1.22, 95% CI: 0.89-1.67, P=0.22). Combining these data with a concurrent MR-based analysis for BMI and WHR with CRC risk (totalling to 18 190 cases, 27 617 controls) provided increased support, ORs for BMI and WHR were 1.26 (95% CI: 1.10-1.44, P=7.7 × 10(-4)) and 1.40 (95% CI: 1.14-1.72, P=1.2 × 10(-3)), respectively. These data provide further evidence for a strong causal relationship between adiposity and the risk of developing CRC highlighting the urgent need for prevention and treatment of adiposity.

  3. Mendelian randomisation analysis strongly implicates adiposity with risk of developing colorectal cancer

    PubMed Central

    Jarvis, David; Mitchell, Jonathan S; Law, Philip J; Palin, Kimmo; Tuupanen, Sari; Gylfe, Alexandra; Hänninen, Ulrika A; Cajuso, Tatiana; Tanskanen, Tomas; Kondelin, Johanna; Kaasinen, Eevi; Sarin, Antti-Pekka; Kaprio, Jaakko; Eriksson, Johan G; Rissanen, Harri; Knekt, Paul; Pukkala, Eero; Jousilahti, Pekka; Salomaa, Veikko; Ripatti, Samuli; Palotie, Aarno; Järvinen, Heikki; Renkonen-Sinisalo, Laura; Lepistö, Anna; Böhm, Jan; Meklin, Jukka-Pekka; Al-Tassan, Nada A; Palles, Claire; Martin, Lynn; Barclay, Ella; Farrington, Susan M; Timofeeva, Maria N; Meyer, Brian F; Wakil, Salma M; Campbell, Harry; Smith, Christopher G; Idziaszczyk, Shelley; Maughan, Timothy S; Kaplan, Richard; Kerr, Rachel; Kerr, David; Buchanan, Daniel D; Win, Aung K; Hopper, John L; Jenkins, Mark A; Lindor, Noralane M; Newcomb, Polly A; Gallinger, Steve; Conti, David; Schumacher, Fred; Casey, Graham; Taipale, Jussi; Aaltonen, Lauri A; Cheadle, Jeremy P; Dunlop, Malcolm G; Tomlinson, Ian P; Houlston, Richard S

    2016-01-01

    Background: Observational studies have associated adiposity with an increased risk of colorectal cancer (CRC). However, such studies do not establish a causal relationship. To minimise bias from confounding we performed a Mendelian randomisation (MR) analysis to examine the relationship between adiposity and CRC. Methods: We used SNPs associated with adult body mass index (BMI), waist-hip ratio (WHR), childhood obesity and birth weight as instrumental variables in a MR analysis of 9254 CRC cases and 18 386 controls. Results: In the MR analysis, the odds ratios (ORs) of CRC risk per unit increase in BMI, WHR and childhood obesity were 1.23 (95% CI: 1.02–1.49, P=0.033), 1.59 (95% CI: 1.08–2.34, P=0.019) and 1.07 (95% CI: 1.03–1.13, P=0.018), respectively. There was no evidence for association between birth weight and CRC (OR=1.22, 95% CI: 0.89–1.67, P=0.22). Combining these data with a concurrent MR-based analysis for BMI and WHR with CRC risk (totalling to 18 190 cases, 27 617 controls) provided increased support, ORs for BMI and WHR were 1.26 (95% CI: 1.10–1.44, P=7.7 × 10−4) and 1.40 (95% CI: 1.14–1.72, P=1.2 × 10−3), respectively. Conclusions: These data provide further evidence for a strong causal relationship between adiposity and the risk of developing CRC highlighting the urgent need for prevention and treatment of adiposity. PMID:27336604

  4. Solar Spicules near and at The Limb, Observed from Hinode

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.

    2009-01-01

    Solar spicules appear as narrow jets emanating from the chromosphere and extending into the corona. They have been observed for over a hundred years,mainly in chromospheric spectral lines such as H-alpha. Because they are at the limit of visibility of ground-based instruments, their nature has long been a puzzle. In recent years however, vast progress has been made in understanding them both theoretically and observationally. Most recently, spicule studies have undergone revolution because of the superior resolution, time cadence, and atmosphere-free observations from the Solar Optical Telescope (SOT) instrument on the Hinode spacecraft. Here we present observations of spicules from {\\sl Hinode} SOT, and consider how the observations from Hinode compare with historical observations. We include data taken in the blue and red wings of Halpha, where the spicules have widths of a few approx.100 kms, and the longest ones reach about 10(exp 4) km in extent,similar to sizes long reported from ground-based instruments. Their dynamics are not easy to generalize, with many showing the upward movement followed by falling or fading, as traditionally reported, but with others showing more dynamic or even ejective aspects. There is a strong transverse component to their motion, as extensively reported previously from the Hinode data as evidence for Alfven waves.

  5. Amateur boxing and risk of chronic traumatic brain injury: systematic review of observational studies.

    PubMed

    Loosemore, Mike; Knowles, Charles H; Whyte, Greg P

    2007-10-20

    To evaluate the risk of chronic traumatic brain injury from amateur boxing. Secondary research performed by combination of sport physicians and clinical academics. DESIGN, DATA SOURCES, AND METHODS: Systematic review of observational studies in which chronic traumatic brain injury was defined as any abnormality on clinical neurological examination, psychometric testing, neuroimaging studies, and electroencephalography. Studies were identified through database (1950 to date) and bibliographic searches without language restrictions. Two reviewers extracted study characteristics, quality, and data, with adherence to a protocol developed from a widely recommended method for systematic review of observational studies (MOOSE). 36 papers had relevant extractable data (from a detailed evaluation of 93 studies of 943 identified from the initial search). Quality of evidence was generally poor. The best quality studies were those with a cohort design and those that used psychometric tests. These yielded the most negative results: only four of 17 (24%) better quality studies found any indication of chronic traumatic brain injury in a minority of boxers studied. There is no strong evidence to associate chronic traumatic brain injury with amateur boxing.

  6. The September 19, 1985 Michoacan Earthquake: Aftershock acceleration data recorded by a temporary installation of strong motion instruments

    NASA Astrophysics Data System (ADS)

    Munguía, Luis; Simila, Gerry W.; McNally, Karen C.; Thompson, Howard

    1986-06-01

    We describe acceleration signals recorded for nine aftershocks of the September 19, 1985 Michoacan earthquake. To obtain this data set, three A-700 Teledyne-Geotech digital strong-motion instruments were operated temporarily at two sites on the José María Morelos (La Villita) Dam, and at a site located at about 12 km to the west of the town of Zihuatanejo. Peak horizontal accelerations of 0.005 g to 0.031 g were recorded at epicentral distances between 10 and 75 km, for earthquakes with magnitude (mb) between 4.5 and 5.3. It was observed that the peak accelerations recorded at a site on the embankment of the dam (near the crest ) are approximately three times those recorded on the abutment bedrock portion of the dam. Although these sites were spatially separated by no more than 300 m, differences among their records are also significant. Waveforms recorded at the embankment site look more complex than those from the abutment site. This fact, as well as the higher peak accelerations on the embankment, provides evidence of a strong influence of the structure of the dam on the ground motion at the embankment site.

  7. From Evidence Based Medicine to Medicine Based Evidence.

    PubMed

    Horwitz, Ralph I; Hayes-Conroy, Allison; Caricchio, Roberto; Singer, Burton H

    2017-11-01

    Evidence based medicine, using randomized controlled trials and meta-analyses as the major tools and sources of evidence about average results for heterogeneous groups of patients, developed as a reaction against poorly designed observational treatment research and physician reliance on personal experience with other patients as a guide to decision-making about a patient at hand. However, these tools do not answer the clinician's question: "Will a given therapeutic regimen help my patient at a given point in her/his clinical course?" We introduce fine-grained profiling of the patient at hand, accompanied by comparative evidence of responses from approximate matches to this patient on whom a contemplated treatment has/has not been administered. This represents medicine based evidence that is tuned to decision-making for the particular patient. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. A high and low noise model for strong motion accelerometers

    NASA Astrophysics Data System (ADS)

    Clinton, J. F.; Cauzzi, C.; Olivieri, M.

    2010-12-01

    We present reference noise models for high-quality strong motion accelerometer installations. We use continuous accelerometer data acquired by the Swiss Seismological Service (SED) since 2006 and other international high-quality accelerometer network data to derive very broadband (50Hz-100s) high and low noise models. The proposed noise models are compared to the Peterson (1993) low and high noise models designed for broadband seismometers; the datalogger self-noise; background noise levels at existing Swiss strong motion stations; and typical earthquake signals recorded in Switzerland and worldwide. The standard strong motion station operated by the SED consists of a Kinemetrics Episensor (2g clip level; flat acceleration response from 200 Hz to DC; <155dB dynamic range) coupled with a 24-bit Nanometrics Taurus datalogger. The proposed noise models are based on power spectral density (PSD) noise levels for each strong motion station computed via PQLX (McNamara and Buland, 2004) from several years of continuous recording. The 'Accelerometer Low Noise Model', ALNM, is dominated by instrument noise from the sensor and datalogger. The 'Accelerometer High Noise Model', AHNM, reflects 1) at high frequencies the acceptable site noise in urban areas, 2) at mid-periods the peak microseismal energy, as determined by the Peterson High Noise Model and 3) at long periods the maximum noise observed from well insulated sensor / datalogger systems placed in vault quality sites. At all frequencies, there is at least one order of magnitude between the ALNM and the AHNM; at high frequencies (> 1Hz) this extends to 2 orders of magnitude. This study provides remarkable confirmation of the capability of modern strong motion accelerometers to record low-amplitude ground motions with seismic observation quality. In particular, an accelerometric station operating at the ALNM is capable of recording the full spectrum of near source earthquakes, out to 100 km, down to M2. Of particular

  9. Evidence for a primary autoimmune type of diabetes mellitus.

    PubMed

    Bottazzo, G F; Cudworth, A G; Moul, D J; Doniach, D; Festenstein, H

    1978-11-04

    Sixty-eight patients with longstanding diabetes and persistent islet-cell antibody and 35 with coexistent diabetes and Graves's disease or primary myxoedema were studied with particular reference to the HLA system and autoantibody patterns. A higher incidence of HLA-B8 than normal was observed in the two groups. An additive relative risk exists when type I diabetes and autoimmune thyroid disease coexist, indicating that different HLA-linked genes may confer susceptibility to the pancreatic and thyroid disorders. Other characteristics, including female predominance, a later onset of diabetes, and a strong family history of autoimmune endocrinopathy, provide further evidence that this form of diabetes is aetiologically distinct from that generally seen in children. These results support the hypothesis of a primary autoimmune type of diabetes mellitus.

  10. Direct experimental evidence for photoinduced strong-coupling polarons in organolead halide perovskite nanoparticles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zheng, Kaibo; Qatar Univ., Doha; Abdellah, Mohamed

    Echoing the roaring success of their bulk coun-terparts, nano-objects built from organolead halide perov-skites (OLHP) present bright prospects for surpassing the performances of their conventional organic and inorganic analogues in photodriven technologies. Unraveling the pho-toinduced charge dynamics is essential for optimizing OLHP optoelectronic functionalities. However, mapping the carri-er-lattice interactions remains challenging, owing to their manifestations on multiple length scales and time scales. By correlating ultrafast time-resolved optical and X-ray absorp-tion measurements, this work reveals the photoinduced formation of strong-coupling polarons in CH 3NH 3PbBr 3 nanoparticles. Such polarons originate from the self-trapping of electrons in the net Coulombic field causedmore » by the dis-placed inorganic nuclei and the oriented organic cations. The transient structural change detected at the Pb L 3 X-ray ab-sorption edge is well captured by a distortion with average bond elongation in the [PbBr 6] 2- motif. As a result, general implications for designing novel OLHP nanomaterials targeting the active utilization of these quasi-particles are outlined.« less

  11. Direct experimental evidence for photoinduced strong-coupling polarons in organolead halide perovskite nanoparticles

    DOE PAGES

    Zheng, Kaibo; Qatar Univ., Doha; Abdellah, Mohamed; ...

    2016-10-28

    Echoing the roaring success of their bulk coun-terparts, nano-objects built from organolead halide perov-skites (OLHP) present bright prospects for surpassing the performances of their conventional organic and inorganic analogues in photodriven technologies. Unraveling the pho-toinduced charge dynamics is essential for optimizing OLHP optoelectronic functionalities. However, mapping the carri-er-lattice interactions remains challenging, owing to their manifestations on multiple length scales and time scales. By correlating ultrafast time-resolved optical and X-ray absorp-tion measurements, this work reveals the photoinduced formation of strong-coupling polarons in CH 3NH 3PbBr 3 nanoparticles. Such polarons originate from the self-trapping of electrons in the net Coulombic field causedmore » by the dis-placed inorganic nuclei and the oriented organic cations. The transient structural change detected at the Pb L 3 X-ray ab-sorption edge is well captured by a distortion with average bond elongation in the [PbBr 6] 2- motif. As a result, general implications for designing novel OLHP nanomaterials targeting the active utilization of these quasi-particles are outlined.« less

  12. Nanoscale Electronic Transport Studies of Novel Strongly Correlated Materials

    NASA Astrophysics Data System (ADS)

    Hardy, Will J.

    Strongly correlated materials are those in which the electron-electron and electron-lattice interactions play pivotal roles in determining many aspects of observable physical behavior, including the electronic and magnetic properties. In this thesis, I describe electronic transport studies of novel strongly correlated materials at the nanoscale. After introducing some basic concepts, briefly reviewing historical development of the field, and discussing the process of making measurements on small length scales, I detail experimental results from studies of four specific materials: two transition metal oxide systems, and two layered transition metal dichalcogenides with intercalated magnetic moments. The first system is a modified version of a classic strongly correlated material, vanadium dioxide (VO2), which here is doped with hydrogen to suppress its metal-insulator transition and stabilize a poorly metallic phase down to liquid helium temperatures. Doped VO2 nanowires, micron flakes, and thin films display magnetoresistance (MR) consistent with weak localization physics, along with mesoscopic resistance fluctuations over short distances, raising questions about how to model transport in bad-metal correlated systems. A second transition metal oxide system is considered next: Quantum wells in SrTiO3 sandwiched between layers of SmTiO3, in which anomalous voltage fluctuation behavior is observed in etched nanostructures at low temperatures. After well-understood alternative origins are ruled out, an explanation is proposed involving a time-varying thermopower due to two-level fluctuations of etching-induced defects. Next, I shift to the topic of layered itinerant magnetic materials with intercalated moments, starting with Fe0.28TaS 2, a hard ferromagnet (FM) with strong spin-orbit coupling. Here, a surprisingly large MR of nearly 70% is observed, an especially striking feature given that the closely related compounds at Fe intercalation fractions of 1/4 or 1/3 have

  13. Energetic electron precipitation characteristics observed from Antarctica during a flux dropout event

    NASA Astrophysics Data System (ADS)

    Clilverd, Mark A.; Cobbett, Neil; Rodger, Craig J.; Brundell, James B.; Denton, Michael H.; Hartley, David P.; Rodriguez, Juan V.; Danskin, Donald; Raita, Tero; Spanswick, Emma L.

    2013-11-01

    from two autonomous VLF radio receiver systems installed in a remote region of the Antarctic in 2012 is used to take advantage of the juxtaposition of the L = 4.6 contour, and the Hawaii-Halley, Antarctica, great circle path as it passes over thick Antarctic ice shelf. The ice sheet conductivity leads to high sensitivity to changing D region conditions, and the quasi constant L shell highlights outer radiation belt processes. The ground-based instruments observed several energetic electron precipitation events over a moderately active 24 h period, during which the outer radiation belt electron flux declined at most energies and subsequently recovered. Combining the ground-based data with low and geosynchronous orbiting satellite observations on 27 February 2012, different driving mechanisms were observed for three precipitation events with clear signatures in phase space density and electron anisotropy. Comparison between flux measurements made by Polar-orbiting Operational Environmental Satellites (POES) in low Earth orbit and by the Antarctic instrumentation provides evidence of different cases of weak and strong diffusion into the bounce loss cone, helping to understand the physical mechanisms controlling the precipitation of energetic electrons into the atmosphere. Strong diffusion events occurred as the <600 keV fluxes began to recover as a result of adiabatic transport of electrons. One event appeared to have a factor of about 10 to 100 times more flux than was reported by POES, consistent with weak diffusion into the bounce loss cone. Two events had a factor of about 3 to 10 times more >30 keV flux than was reported by POES, more consistent with strong diffusion conditions.

  14. Evidence for the multiverse in the standard model and beyond

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hall, Lawrence J.; Nomura, Yasunori

    2008-08-01

    In any theory it is unnatural if the observed values of parameters lie very close to special values that determine the existence of complex structures necessary for observers. A naturalness probability P is introduced to numerically evaluate the degree of unnaturalness. If P is very small in all known theories, corresponding to a high degree of fine-tuning, then there is an observer naturalness problem. In addition to the well-known case of the cosmological constant, we argue that nuclear stability and electroweak symmetry breaking represent significant observer naturalness problems. The naturalness probability associated with nuclear stability depends on the theory ofmore » flavor, but for all known theories is conservatively estimated as P{sub nuc} < or approx. (10{sup -3}-10{sup -2}), and for simple theories of electroweak symmetry breaking P{sub EWSB} < or approx. (10{sup -2}-10{sup -1}). This pattern of unnaturalness in three different arenas, cosmology, nuclear physics, and electroweak symmetry breaking, provides evidence for the multiverse, since each problem may be easily solved by environmental selection. In the nuclear case the problem is largely solved even if the multiverse distribution for the relevant parameters is relatively flat. With somewhat strongly varying distributions, it is possible to understand both the close proximity to neutron stability and the values of m{sub e} and m{sub d}-m{sub u} in terms of the electromagnetic mass difference between the proton and neutron, {delta}{sub EM}{approx_equal}1{+-}0.5 MeV. It is reasonable that multiverse distributions are strong functions of Lagrangian parameters, since they depend not only on the landscape of vacua, but also on the population mechanism, ''integrating out'' other parameters, and on a density of observers factor. In any theory with mass scale M that is the origin of electroweak symmetry breaking, strongly varying multiverse distributions typically lead either to a little hierarchy v

  15. Evidence for a Circum-Nuclear and Ionised Absorber in the X-ray Obscured Broad Line Radio Galaxy 3C 445

    NASA Technical Reports Server (NTRS)

    Braito, V.; Reeves, J. N.; Sambruna, R. M.; Gofford, J.

    2012-01-01

    Here we present the results of a Suzaku observation of the Broad Line Radio Galaxy 3C 445. We confirm the results obtained with the previous X-ray observations which unveiled the presence of several soft X-ray emission lines and an overall X-ray emission which strongly resembles a typical Seyfert 2 despite of the optical classification as an unobscured AGN. The broad band spectrum allowed us to measure for the first time the amount of reflection (R approximately 0.9) which together with the relatively strong neutral Fe Ka emission line (EW approximately 100 eV) strongly supports a scenario where a Compton-thick mirror is present. The primary X ray continuum is strongly obscured by an absorber with a column density of NH = 2 - 3 x 10(exp 23) per square centimeter. Two possible scenarios are proposed for the absorber: a neutral partial covering or a mildly ionised absorber with an ionisation parameter log xi approximately 1.0 erg centimeter per second. A comparison with the past and more recent X-ray observations of 3C 445 performed with XMM-Newton and Chandra is presented, which provided tentative evidence that the ionised and outflowing absorber varied. We argue that the absorber is probably associated with an equatorial diskwind located within the parsec scale molecular torus.

  16. OBSERVATIONAL EVIDENCE OF BACK REACTION ON THE SOLAR SURFACE ASSOCIATED WITH CORONAL MAGNETIC RESTRUCTURING IN SOLAR ERUPTIONS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang Haimin; Liu Chang, E-mail: haimin.wang@njit.ed, E-mail: chang.liu@njit.ed

    2010-06-20

    Most models of solar eruptions assume that coronal field lines are anchored in the dense photosphere and thus the photospheric magnetic fields would not have rapid, irreversible changes associated with eruptions resulted from the coronal magnetic reconnection. Motivated by the recent work of Hudson et al. on quantitatively evaluating the back reaction due to energy release from the coronal fields, in this Letter we synthesize our previous studies and present analysis of new events about flare-related changes of photospheric magnetic fields. For the 11 X-class flares where vector magnetograms are available, we always find an increase of transverse field atmore » the polarity inversion line (PIL) although only four events had measurements with 1 minute temporal resolution. We also discuss 18 events with 1 minute cadence line-of-sight magnetogram observation, which all show prominent changes of magnetic flux contained in the flaring {delta} spot region. Except in one case, the observed limbward flux increases while diskward flux decreases rapidly and irreversibly after flares. This observational evidence provides support, either directly or indirectly, for the theory and prediction of Hudson et al. that the photospheric magnetic fields must respond to coronal field restructuring and turn to a more horizontal state near the PIL after eruptions.« less

  17. Evidence-based surgery: barriers, solutions, and the role of evidence synthesis.

    PubMed

    Garas, George; Ibrahim, Amel; Ashrafian, Hutan; Ahmed, Kamran; Patel, Vanash; Okabayashi, Koji; Skapinakis, Petros; Darzi, Ara; Athanasiou, Thanos

    2012-08-01

    Surgery is a rapidly evolving field, making the rigorous testing of emerging innovations vital. However, most surgical research fails to employ randomized controlled trials (RCTs) and has particularly been based on low-quality study designs. Subsequently, the analysis of data through meta-analysis and evidence synthesis is particularly difficult. Through a systematic review of the literature, this article explores the barriers to achieving a strong evidence base in surgery and offers potential solutions to overcome the barriers. Many barriers exist to evidence-based surgical research. They include enabling factors, such as funding, time, infrastructure, patient preference, ethical issues, and additionally barriers associated with specific attributes related to researchers, methodologies, or interventions. Novel evidence synthesis techniques in surgery are discussed, including graphics synthesis, treatment networks, and network meta-analyses that help overcome many of the limitations associated with existing techniques. They offer the opportunity to assess gaps and quantitatively present inconsistencies within the existing evidence of RCTs. Poorly or inadequately performed RCTs and meta-analyses can give rise to incorrect results and thus fail to inform clinical practice or revise policy. The above barriers can be overcome by providing academic leadership and good organizational support to ensure that adequate personnel, resources, and funding are allocated to the researcher. Training in research methodology and data interpretation can ensure that trials are conducted correctly and evidence is adequately synthesized and disseminated. The ultimate goal of overcoming the barriers to evidence-based surgery includes the improved quality of patient care in addition to enhanced patient outcomes.

  18. Strong spin-lattice coupling in CrSiTe 3

    DOE PAGES

    Casto, L. D.; Clune, A. J.; Yokosuk, M. O.; ...

    2015-03-19

    CrSiTe 3 has attracted recent interest as a candidate single-layer ferromagnetic semiconductor, but relatively little is known about the bulk properties of this material. Here, we report single-crystal X-ray diffraction, magnetic properties, thermal conductivity, vibrational, and optical spectroscopies and compare our findings with complementary electronic structure and lattice dynamics principles calculations. The high temperature paramagnetic phase is characterized by strong spin-lattice interactions that give rise to glassy behavior, negative thermal expansion, and an optical response that reveals that CrSiTe 3 is an indirect gap semiconductor with indirect and direct band gaps at 0.4 and 1.2 eV, respectively. Measurements of themore » phonons across the 33 K ferromagnetic transition provide additional evidence for strong coupling between the magnetic and lattice degrees of freedom. In conclusion, the Si-Te stretching and Te displacement modes are sensitive to the magnetic ordering transition, a finding that we discuss in terms of the superexchange mechanism. Lastly, spin-lattice coupling constants are also extracted.« less

  19. Strong Navajo Marriages

    ERIC Educational Resources Information Center

    Skogrand, Linda; Mueller, Mary Lou; Arrington, Rachel; LeBlanc, Heidi; Spotted Elk, Davina; Dayzie, Irene; Rosenbrand, Reva

    2008-01-01

    The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths:…

  20. ERP evidence for conflict in contingency learning.

    PubMed

    Whitehead, Peter S; Brewer, Gene A; Blais, Chris

    2017-07-01

    The proportion congruency effect refers to the observation that the magnitude of the Stroop effect increases as the proportion of congruent trials in a block increases. Contemporary work shows that proportion effects can be driven by both context and individual items, and are referred to as context-specific proportion congruency (CSPC) and item-specific proportion congruency (ISPC) effects, respectively. The conflict-modulated Hebbian learning account posits that these effects manifest from the same mechanism, while the parallel episodic processing model posits that the ISPC can occur by simple associative learning. Our prior work showed that the neural correlates of the CSPC is an N2 over frontocentral electrode sites approximately 300 ms after stimulus onset that predicts behavioral performance. There is strong consensus in the field that this N2 signal is associated with conflict detection in the medial frontal cortex. The experiment reported here assesses whether the same qualitative electrophysiological pattern of results holds for the ISPC. We find that the spatial topography of the N2 is similar but slightly delayed with a peak onset of approximately 300 ms after stimulus onset. We argue that this provides strong evidence that a single common mechanism-conflict-modulated Hebbian learning-drives both the ISPC and CSPC. © 2017 Society for Psychophysiological Research.