HFT events - Shallow moonquakes. [High-Frequency Teleseismic

NASA Technical Reports Server (NTRS)

Nakamura, Y.

1977-01-01

A few large distant seismic events of distinctly high signal frequency, designated HFT (high-frequency teleseismic) events, are observed yearly by the Apollo lunar seismic network. Their sources are located on or near the surface of the moon, leaving a large gap in seismic activity between the zones of HFT sources and deep moonquakes. No strong regularities are found in either their spatial or temporal distributions. Several working hypotheses for the identity of these sources have advanced, but many characteristics of the events seem to favor a hypothesis that they are shallow moonquakes. Simultaneous observations of other lunar phenomena may eventually enable the determination of their true identity.

Azimuthal propagation of storm time Pc 5 waves observed simultaneously by geostationary satellites GOES 2 and GOES 3

NASA Astrophysics Data System (ADS)

Lin, C. S.; Barfield, J. N.

1985-11-01

Storm-time Pc 5 wave events observed simultaneously by the GOES 2 and GOES 3 satellites in the afternoon sector during the 1-year interval of March 1979 to February 1980 are surveyed to learn the wave propagation. Essentially, all storm-time Pc 5 waves (approximately 93 percent) are found to propagate westward azimuthally with a velocity of 5 to 50 km/s and a wavelength of 1000 km to 9000 km (Only two of 30 events had eastward propagation, with a velocity of about 150 km/s). It is concluded that westward propagating waves are excited by ion drift instabilities associated with the ion ring current, and that the eastward propagating waves are excited by surface waves on the magnetopause through Kelvin-Helmholtz instability.

Simultaneous lidar and EOS MLS measurements, and modeling, of a rare polar ozone filament event over Mauna Loa Observatory, Hawaii

NASA Astrophysics Data System (ADS)

Leblanc, Thierry; Tripathi, Om Prakash; McDermid, I. Stuart; Froidevaux, Lucien; Livesey, N. J.; Read, W. G.; Waters, J. W.

2006-08-01

In mid-March 2005, a rare lower stratospheric polar vortex filamentation event was observed simultaneously by the JPL lidar at Mauna Loa Observatory, Hawaii, and by the EOS MLS instrument onboard the Aura satellite. The event coincided with the beginning of the spring 2005 final warming. On 16 March, the filament was observed by lidar around 0600 UT between 415 K and 455 K, and by MLS six hours earlier. It was seen on both the lidar and MLS profiles as a layer of enhanced ozone, peaking at 1.7 ppmv in a region where the climatological values are usually around or below 1 ppmv. Ozone profiles measured by lidar and MLS were compared to profiles from the Chemical Transport Model MIMOSA-CHIM. The agreement between lidar, MLS, and the model is excellent considering the difference in the sampling techniques. MLS was also able to identify the filament at another location north of Hawaii.

Dynamic Processes in Be Star Atmospheres.. 6; Simultaneous X-Ray, Ultraviolet, and Optical Variations in lambda Eridani

NASA Technical Reports Server (NTRS)

Smith, Myron A.; Murakami, T.; Ezuka, H.; Anandarao, B. G.; Chakraborty, A.; Corcoran, M. F.; Hirata, R.

1995-01-01

This report describes a joint X ray/ultraviolet/ground based study of the abnormal Be star lambda Eri which has previously shown evidence of X ray flaring from Rosat observations in 1991. The 1991 flare event caught the astronomical hot star community by surprise because x ray flares have not been observed from other single B-type stars, before or since. Both optical (H-alpha) and UV/Voyager observations provide evidence for transient heating events near the surface of lambda Eri.

Raman imaging of molecular dynamics during cellular events

NASA Astrophysics Data System (ADS)

Fujita, Katsumasa

2017-07-01

To overcome the speed limitation in Raman imaging, we have developed a microscope system that detects Raman spectra from hundreds of points in a sample simultaneously. The sample was illuminated by a line-shaped focus, and Raman scattering from the illuminated positions was measured simultaneously by an imaging spectrophotometer. We applied the line-illumination technique to observe the dynamics of intracellular molecules during cellular events. We found that intracellular cytochrome c can be clearly imaged by resonant Raman scattering. We demonstrated label-free imaging of redistribution of cytochrome c during apoptosis and osteoblastic mineralization. We also proposed alkyne-tagged Raman imaging to observe small molecules in living cells. Due to its small size and the unique Raman band, alkyne can tag molecules without strong perturbation to molecular functions and with the capability to be detected separately from endogenous molecules.

Simultaneous response of NmF2 and GPS-TEC to storm events at Ilorin

NASA Astrophysics Data System (ADS)

Joshua, B. W.; Adeniyi, J. O.; Oladipo, O. A.; Doherty, P. H.; Adimula, I. A.; Olawepo, A. O.; Adebiyi, S. J.

2018-06-01

A comparative study of both TEC and NmF2 variations during quiet and disturbed conditions has been investigated using simultaneous measurements from dual frequency Global Positioning System (GPS) receiver and a DPS-4 Digisonde co-located at Ilorin (Geog. Lat. 8.50°N, Long. 4.50°E, dip. - 7.9°). The results of the quiet time variations of the two parameters show some similarities as well as differences in their structures. The values of both parameters generally increase during the sunrise period attaining a peak around the noon and then decaying towards the night time. The onset time of the sunrise growth is observed to be earlier in TEC than in NmF2. The rate of decay of TEC was observed to be faster than that of the NmF2 in most cases. Also, the noon 'bite-outs', leading to the formation of pre-noon and post-noon peaks, are prominent in the NmF2 structure and was hardly noticed in TEC. Results of the variations of both TEC and NmF2 during the 5 April, 10 May and 3 August 2010 geomagnetic storm events showed a simultaneous deviations of both parameters from the quiet time behavior. The magnitude of the deviations is however most pronounced in NmF2 structure than in TEC. We also found that the enhancement observed in the two parameters during the storm events generally corresponds to decrease in hmF2.

Particle formation and growth at five rural and urban sites

NASA Astrophysics Data System (ADS)

Jeong, C.-H.; Evans, G. J.; McGuire, M. L.; Chang, R. Y.-W.; Abbatt, J. P. D.; Zeromskiene, K.; Mozurkewich, M.; Li, S.-M.; Leaitch, W. R.

2010-08-01

Ultrafine particle (UFP) number and size distributions were simultaneously measured at five urban and rural sites during the summer of 2007 in Ontario, Canada as part of the Border Air Quality and Meteorology Study (BAQS-Met 2007). Particle formation and growth events at these five sites were classified based on their strength and persistence as well as the variation in geometric mean diameter. Regional nucleation and growth events and local short-lived strong nucleation events were frequently observed at the near-border rural sites, upwind of industrial sources. Surprisingly, the particle number concentrations at one of these sites were higher than the concentrations at a downtown site in a major city, despite its high traffic density. Regional nucleation and growth events were favored during intense solar irradiance and in less polluted cooler drier air. The most distinctive regional particle nucleation and growth event during the campaign was observed simultaneously at all five sites, which were up to 350 km apart. Although the ultrafine particle concentrations and size distributions generally were spatially heterogeneous across the region, a more uniform spatial distribution of UFP across the five areas was observed during this regional nucleation event. Thus, nucleation events can cover large regions, contributing to the burden of UFP in cities and potentially to the associated health impacts on urban populations. Local short-lived nucleation events at the three near-border sites during this summer three-week campaign were associated with high SO2, which likely originated from US and Canadian industrial sources. Hence, particle formation in southwestern Ontario appears to often be related to anthropogenic gaseous emissions but biogenic emissions at times also contribute. Longer-term studies are needed to help resolve the relative contributions of anthropogenic and biogenic emissions to nucleation and growth in this region.

Comparative Study of Three Reconnection X-Line Models at the Earth's Dayside Magnetopause Using In Situ Observations

NASA Astrophysics Data System (ADS)

Souza, V. M. C. E. S.; Gonzalez, W.; Sibeck, D. G.; Koga, D.; Walsh, B.; Mendes, O., Jr.

2017-12-01

This work examines the large-scale aspects of magnetic field reconnection at the Earth's dayside magnetopause. We use two sets of reconnection events, which are identified mostly by the in situ detection of accelerated and Alfvénic plasma flows. We intercompare three analytical models that predict the reconnection X-line location and orientation, namely the Trattner et al., (2007) and Swisdak and Drake (2007) models, and also a modified version of the component merging model (Gonzalez and Mozer 1974, Sonnerup 1974). In the first set of reconnection observations, we show three fortuitous, quasi-simultaneous dayside magnetopause crossing events where two widely separated spacecraft detect reconnection signatures, and the X-line location and orientation can be inferred from the observations. We compare X-line model predictions to those inferred from observations. These three reconnection events indicate the presence of an extended (>7 Earth radii in length), component-type reconnection X-line on Earth's dayside magnetopause connecting and structuring the reconnection signatures at locations far apart. In the second set of reconnection events, we analyze the X-line models' performance in predicting the observed reconnection outflow direction, i.e., its north-south and/or east-west senses, in a total of 75 single, rather than multiple and quasi-simultaneous, magnetopause crossing events, where reconnection-associated plasma flows were clearly present. We found that the Swisdak and Drake's (2007) X-line model performs slightly better, albeit not statistically significant, when predicting both accelerated plasma flow north-south and east-west components in 73% and 53% of the cases, respectively, as compared to the Trattner et al., (2007) model (70% north-south, 42% east-west), and the modified component merging model (66% north-south, 50% east-west).

Characteristics of medium- and large-scale TIDs over Japan derived from OI 630-nm nightglow observation

NASA Astrophysics Data System (ADS)

Kubota, M.; Fukunishi, H.; Okano, S.

2001-07-01

A new optical instrument for studying upper atmospheric dynamics, called the Multicolor All-sky Imaging System (MAIS), has been developed. The MAIS can obtain all-sky images of airglow emission at two different wavelengths simultaneously with a time resolution of several minutes. Since December 1991, imaging observations with the MAIS have been conducted at the Zao observatory (38.09°N, 140.56°E). From these observations, two interesting events with wave structures have been detected in OI 630-nm nightglow images. The first event was observed on the night of June 2/3, 1992 during a geomagnetically quiet period. Simultaneous data of ionospheric parameters showed that they are caused by propagation of the medium-scale traveling ionospheric disturbance (TID). Phase velocity and horizontal wavelength determined from the image data are 45-100 m/s and ~280 km, and the propagation direction is south-westward. The second event was observed on the night of February 27/28, 1992 during a geomagnetic storm. It is found that a large enhancement of OI 630-nm emission is caused by a propagation of the large-scale TID. Meridional components of phase velocities and wavelengths determined from ionospheric data are 305-695 m/s (southward) and 930-5250 km. The source of this large-scale TID appears to be auroral processes at high latitudes.

Action-outcome learning and prediction shape the window of simultaneity of audiovisual outcomes.

PubMed

Desantis, Andrea; Haggard, Patrick

2016-08-01

To form a coherent representation of the objects around us, the brain must group the different sensory features composing these objects. Here, we investigated whether actions contribute in this grouping process. In particular, we assessed whether action-outcome learning and prediction contribute to audiovisual temporal binding. Participants were presented with two audiovisual pairs: one pair was triggered by a left action, and the other by a right action. In a later test phase, the audio and visual components of these pairs were presented at different onset times. Participants judged whether they were simultaneous or not. To assess the role of action-outcome prediction on audiovisual simultaneity, each action triggered either the same audiovisual pair as in the learning phase ('predicted' pair), or the pair that had previously been associated with the other action ('unpredicted' pair). We found the time window within which auditory and visual events appeared simultaneous increased for predicted compared to unpredicted pairs. However, no change in audiovisual simultaneity was observed when audiovisual pairs followed visual cues, rather than voluntary actions. This suggests that only action-outcome learning promotes temporal grouping of audio and visual effects. In a second experiment we observed that changes in audiovisual simultaneity do not only depend on our ability to predict what outcomes our actions generate, but also on learning the delay between the action and the multisensory outcome. When participants learned that the delay between action and audiovisual pair was variable, the window of audiovisual simultaneity for predicted pairs increased, relative to a fixed action-outcome pair delay. This suggests that participants learn action-based predictions of audiovisual outcome, and adapt their temporal perception of outcome events based on such predictions. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Enrichment of heavy nuclei in He-3-rich flares. [Imp-7 observed solar events

NASA Technical Reports Server (NTRS)

Hurford, G. J.; Mewaldt, R. A.; Stone, E. C.; Vogt, R. E.

1975-01-01

IMP-7 observations of five solar-flare particle events characterized by He-3 enrichment are reported which show that such events are also enriched in nuclei with charges (Z) of at least 6. The ratio of these nuclei to H-1 at approximately 3 MeV/nucleon was found to be enriched by about 10 to 100 times, while the ratio with respect to He-4 was enriched by about 3 to 30 times. It is suggested that the simultaneous enhancement of He-3 and the heavier nuclei as well as the absence of H-2 and H-3 during the observed events may be partly due to a preferential acceleration process which depends on the ratio of the square of the charge to the atomic weight of the nuclei.

Early Binocular Input Is Critical for Development of Audiovisual but Not Visuotactile Simultaneity Perception.

PubMed

Chen, Yi-Chuan; Lewis, Terri L; Shore, David I; Maurer, Daphne

2017-02-20

Temporal simultaneity provides an essential cue for integrating multisensory signals into a unified perception. Early visual deprivation, in both animals and humans, leads to abnormal neural responses to audiovisual signals in subcortical and cortical areas [1-5]. Behavioral deficits in integrating complex audiovisual stimuli in humans are also observed [6, 7]. It remains unclear whether early visual deprivation affects visuotactile perception similarly to audiovisual perception and whether the consequences for either pairing differ after monocular versus binocular deprivation [8-11]. Here, we evaluated the impact of early visual deprivation on the perception of simultaneity for audiovisual and visuotactile stimuli in humans. We tested patients born with dense cataracts in one or both eyes that blocked all patterned visual input until the cataractous lenses were removed and the affected eyes fitted with compensatory contact lenses (mean duration of deprivation = 4.4 months; range = 0.3-28.8 months). Both monocularly and binocularly deprived patients demonstrated lower precision in judging audiovisual simultaneity. However, qualitatively different outcomes were observed for the two patient groups: the performance of monocularly deprived patients matched that of young children at immature stages, whereas that of binocularly deprived patients did not match any stage in typical development. Surprisingly, patients performed normally in judging visuotactile simultaneity after either monocular or binocular deprivation. Therefore, early binocular input is necessary to develop normal neural substrates for simultaneity perception of visual and auditory events but not visual and tactile events. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characteristics of formation and growth of atmospheric nanoparticles observed at four regional background sites in Korea

NASA Astrophysics Data System (ADS)

Kim, Yumi; Kim, Sang-Woo; Yoon, Soon-Chang; Park, Jin-Soo; Lim, Jae-Hyun; Hong, Jihyung; Lim, Han-Cheol; Ryu, Jegyu; Lee, Chul-Kyu; Heo, Bok-Haeng

2016-02-01

Measurements of the number concentration and size distribution of atmospheric nanoparticles were conducted at four sites on the west coast of the Korean Peninsula by using identical scanning mobility particle sizers (SMPSs) in October 2012. The new particle formation and subsequent growth (NPF) of atmospheric nanoparticles, which were identified by the cyclostationary empirical orthogonal function (CSEOF) analysis technique, was observed on 11 out of 21 days at the Baengnyeong-do Comprehensive Monitoring Observatory (BCMO); and on 10 out of 21 days at the Korea Global Atmosphere Watch Center (KGAWC) from October 9 to 29, 2012. We also observed NPF events for 9 out of 21 days at both the Gosan Climate Observatory (GCO) and the Jeju Comprehensive Monitoring Observatory (JCMO). During the study period, NPF was simultaneously observed for five days at all four sites, which indicates that the NPF event had a spatial extent of at least 540 km. A cold, dry and cloud-free continental air mass originated from northern China, formed favorable environmental conditions (e.g., increasing solar insolation at the surface) on simultaneous NPF at the four sites. These synoptic weather patterns were closely associated with an extraordinary typhoon passing over the south of Japan. The mean values of particle formation rates at BCMO (1.26 cm- 3 s- 1) and KGAWC (1.49 cm- 3 s- 1) were relatively higher than those at GCO (0.39 cm- 3 s- 1) and JCMO (0.74 cm- 3 s- 1), however, the growth rate showed a similar level among four sites. An increase in the spatial homogeneity and inter-site correlation of atmospheric particles among the four sites was apparent for small particles (diameter < 30 nm) on simultaneous NPF event days.

Properties of Coronal Shocks at the Origin of SEP events Observed by Only One Single Spacecraft

NASA Astrophysics Data System (ADS)

Lario, D.; Kwon, R.

2017-12-01

The simultaneous observation of solar energetic particle (SEP) events by multiple spacecraft distributed in the interplanetary medium depends not only on the spatial separation among the different spacecraft, but also on the properties of the particle sources and the characteristics of the SEP transport in interplanetary space. Among the SEP events observed by STEREO-A, STEREO-B and/or near-Earth spacecraft during solar cycle 24, we select SEP events observed by a single spacecraft (specifically, the SEP events observed only by near-Earth spacecraft on 2012 April 5, 2011 September 4, and 2013 August 17). We analyze whether the properties of the coronal shock associated with the origin of the events (as seen in extreme-ultraviolet and white-light coronal images) differ from those associated with SEP events observed by two or three spacecraft. For the selected events we find that the associated CMEs are, in general, narrower than those associated with SEP events observed by two or three spacecraft. The confined extension of the parent coronal shock and the absence of magnetic connection between distant spacecraft and the regions of the expanding coronal shock able to efficiently accelerate SEPs seem to be the conditions leading to intense SEP events observed only over narrow regions of interplanetary space by spacecraft magnetically connected to regions close to the parent eruption site. Weak and gradual intensity increases observed in extended regions of space might involve transport processes and/or later connections established with interplanetary shocks. Systematic analyses of a larger number of events are required before drawing firm conclusions.

'Two go together': Near-simultaneous moment release of two asperities during the 2016 Mw 6.6 Muji, China earthquake

NASA Astrophysics Data System (ADS)

Bie, Lidong; Hicks, Stephen; Garth, Thomas; Gonzalez, Pablo; Rietbrock, Andreas

2018-06-01

On 25 November 2016, a Mw 6.6 earthquake ruptured the Muji fault in western Xinjiang, China. We investigate the earthquake rupture independently using geodetic observations from Interferometric Synthetic Aperture Radar (InSAR) and regional seismic recordings. To constrain the fault geometry and slip distribution, we test different combinations of fault dip and slip direction to reproduce InSAR observations. Both InSAR observations and optimal distributed slip model suggest buried rupture of two asperities separated by a gap of greater than 5 km. Additional seismic gaps exist at the end of both asperities that failed in the 2016 earthquake. To reveal the dynamic history of asperity failure, we inverted regional seismic waveforms for multiple centroid moment tensors and construct a moment rate function. The results show a small centroid time gap of 2.6 s between the two sub-events. Considering the >5 km gap between the two asperities and short time interval, we propose that the two asperities failed near-simultaneously, rather than in a cascading rupture propagation style. The second sub-event locates ∼39 km to the east of the epicenter and the centroid time is at 10.7 s. It leads to an estimate of average velocity of 3.7 km/s as an upper bound, consistent with upper crust shear wave velocity in this region. We interpret that the rupture front is propagating at sub-shear wave velocities, but that the second sub-event has a reduced or asymmetric rupture time, leading to the apparent near-simultaneous moment release of the two asperities.

Impacts of space weather events on the structure of the upper atmosphere

NASA Astrophysics Data System (ADS)

Lee, Y.; Mahaffy, P. R.; Benna, M.; Elrod, M. K.

2017-12-01

Due to the absence of the intrinsic magnetic field, Mars' upper atmosphere is vulnerable to the solar wind, which directly strips away the Martian upper atmosphere via various mechanisms, resulting in interesting global phenomena that are observable. The Mars Atmosphere and Volatile EvolutioN (MAVEN) has observed the responses of the upper atmosphere such as Interplanetary Coronal Mass Ejections (ICMEs) and Solar flare events spanning from November 2014 to the present. A comprehensive set of observations taken by the MAVEN instrument package enables the better characterization of the thermospheric and ionospheric behavior affected by various space weather events. The observed impacts include changes in the upper atmospheric and ionospheric density and temperature, enhancements of atmospheric loss rate of ions and neutrals, and changes in important boundary layers. The measurements by plasma and field instruments allows the upstream monitoring of the solar EUV, solar energetic particles, and Interplanetary Magnetic Field (IMF) simultaneously and provide additional information of the near-Mars space weather disturbances. In addition, at low altitudes near the periapsis of the spacecraft, the simultaneous measurements of the magnetic field and properties of the thermosphere and ionosphere allow the analysis of the effects of the local crustal magnetic fields. Here, adding to the reported MAVEN observations of the space weather impacts at Mars, we analyze the responses of the upper atmosphere to the mars-impacting space weather events observed by MAVEN. We focus mainly on the responses of the density and temperature structures, which in turn allow us to examine the effects on the important atmospheric layers such as the M2 layer and transition region from the thermosphere to exosphere.

Spatial distribution and occurrence probability of regional new particle formation events in eastern China

NASA Astrophysics Data System (ADS)

Shen, Xiaojing; Sun, Junying; Kivekäs, Niku; Kristensson, Adam; Zhang, Xiaoye; Zhang, Yangmei; Zhang, Lu; Fan, Ruxia; Qi, Xuefei; Ma, Qianli; Zhou, Huaigang

2018-01-01

In this work, the spatial extent of new particle formation (NPF) events and the relative probability of observing particles originating from different spatial origins around three rural sites in eastern China were investigated using the NanoMap method, using particle number size distribution (PNSD) data and air mass back trajectories. The length of the datasets used were 7, 1.5, and 3 years at rural sites Shangdianzi (SDZ) in the North China Plain (NCP), Mt. Tai (TS) in central eastern China, and Lin'an (LAN) in the Yangtze River Delta region in eastern China, respectively. Regional NPF events were observed to occur with the horizontal extent larger than 500 km at SDZ and TS, favoured by the fast transport of northwesterly air masses. At LAN, however, the spatial footprint of NPF events was mostly observed around the site within 100-200 km. Difference in the horizontal spatial distribution of new particle source areas at different sites was connected to typical meteorological conditions at the sites. Consecutive large-scale regional NPF events were observed at SDZ and TS simultaneously and were associated with a high surface pressure system dominating over this area. Simultaneous NPF events at SDZ and LAN were seldom observed. At SDZ the polluted air masses arriving over the NCP were associated with higher particle growth rate (GR) and new particle formation rate (J) than air masses from Inner Mongolia (IM). At TS the same phenomenon was observed for J, but GR was somewhat lower in air masses arriving over the NCP compared to those arriving from IM. The capability of NanoMap to capture the NPF occurrence probability depends on the length of the dataset of PNSD measurement but also on topography around the measurement site and typical air mass advection speed during NPF events. Thus the long-term measurements of PNSD in the planetary boundary layer are necessary in the further study of spatial extent and the probability of NPF events. The spatial extent, relative probability of occurrence, and typical evolution of PNSD during NPF events presented in this study provide valuable information to further understand the climate and air quality effects of new particle formation.

Geomagnetic transmission disturbances and heavy-ion fluences observed in low Earth orbit during the solar energetic particle events of October 1989.

PubMed

Boberg, P R; Tylka, A J; Adams, J H; Beahm, L P; Fluckiger, E O; Kleis, T; Kobel, E

1996-01-01

The large solar energetic particle (SEP) events and simultaneous large geomagnetic disturbances observed during October 1989 posed a significant, rapidly evolving space radiation hazard. Using data from the GOES-7, NOAA-10, IMP-8 and LDEF satellites, we determined the geomagnetic transmission, heavy ion fluences, mean Fe ionic charge state, and effective radiation hazard observed in low Earth orbit (LEO) for these SEPs. We modeled the geomagnetic transmission by tracing particles through the combination of the internal International Geomagnetic Reference Field (IGRF) and the Tsyganenko (1989) magnetospheric field models, extending the modeling to large geomagnetic disturbances. We used our results to assess the radiation hazard such very large SEP events would pose in the anticipated 52 degrees inclination space station orbit.

Measurement of the Top Quark Mass Simultaneously in Dilepton and Lepton + Jets Decay Channels

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

Fedorko, Wojciech T.

2008-12-01

The authors present the first measurement of the top quark mass using simultaneously data from two decay channels. They use a data sample of √s = 1.96 TeV collisions with integrated luminosity of 1.9 fb -1 collected by the CDF II detector. They select dilepton and lepton + jets channel decays of tmore » $$\\bar{t}$$ pairs and reconstruct two observables in each topology. They use non-parametric techniques to derive probability density functions from simulated signal and background samples. The observables are the reconstructed top quark mass and the scalar sum of transverse energy of the event in the dilepton topology and the reconstructed top quark mass and the invariant mass of jets from the W boson decay in lepton + jets channel. They perform a simultaneous fit for the top quark mass and the jet energy scale which is constrained in situ by the hadronic W boson resonance from the lepton + jets channel. Using 144 dilepton candidate events and 332 lepton + jets candidate events they measure: M top = 171.9 ± 1.7 (stat. + JES) ± 1.1 (other sys.) GeV/c 2 = 171.9 ± 2.0 GeV/c 2. The measurement features a robust treatment of the systematic uncertainties, correlated between the two channels and develops techniques for a future top quark mass measurement simultaneously in all decay channels. Measurements of the W boson mass and the top quark mass provide a constraint on the mass of the yet unobserved Higgs boson. The Higgs boson mass implied by measurement presented here is higher than Higgs boson mass implied by previously published, most precise CDF measurements of the top quark mass in lepton + jets and dilepton channels separately.« less

Non-stationary Alfvén resonator: new results on Pc1 pearls and IPDP events

NASA Astrophysics Data System (ADS)

Mursula, K.; Prikner, K.; Feygin, F. Z.; Bräysy, T.; Kangas, J.; Kerttula, R.; Pollari, P.; Pikkarainen, T.; Pokhotelov, O. A.

2000-03-01

We analyse a Pc1 pearl event observed by the Finnish search-coil magnetometer network on 15 December 1984, which subsequently developed into a structured IPDP after a substorm onset. The EISCAT radar was simultaneously monitoring the mid- to high-latitude ionosphere. We have calculated the ionospheric resonator properties during the different phases of the event using EISCAT observations. Contrary to the earlier results, we find that the Pc1/IPDP (Interval of Pulsations of Diminishing Period) frequency observed on the ground corresponds to the maximum of the transmission coefficient rather than that of the reflection coefficient. This casts strong doubts on the bouncing wave packet model of Pc1 pearls. Instead, we present evidence for an alternative model of pearl formation in which long-period ULF waves modulate the Pc1 growth rate. Moreover, we propose a new model for IPDP formation, whereby the ionosphere acts as an active agent in forming the IPDP signal on the ground. The model calculations show that the ionospheric resonator properties can be modified during the event so that the resonator eigenfrequency increases according to the observed frequency increase during the IPDP phase. We suggest that the IPDP signal on the ground is a combined effect of the frequency increase in the magnetospheric wave source and the simultaneous increase of the resonator eigenfrequency. The need for such a complicated matching of the two factors explains the rarity of IPDPs on the ground despite the ubiquitous occurrence of EMIC waves in the magnetosphere and the continuous substorm cycle.

Vitrification and levitation of a liquid droplet on liquid nitrogen.

PubMed

Song, Young S; Adler, Douglas; Xu, Feng; Kayaalp, Emre; Nureddin, Aida; Anchan, Raymond M; Maas, Richard L; Demirci, Utkan

2010-03-09

The vitrification of a liquid occurs when ice crystal formation is prevented in the cryogenic environment through ultrarapid cooling. In general, vitrification entails a large temperature difference between the liquid and its surrounding medium. In our droplet vitrification experiments, we observed that such vitrification events are accompanied by a Leidenfrost phenomenon, which impedes the heat transfer to cool the liquid, when the liquid droplet comes into direct contact with liquid nitrogen. This is distinct from the more generally observed Leidenfrost phenomenon that occurs when a liquid droplet is self-vaporized on a hot plate. In the case of rapid cooling, the phase transition from liquid to vitrified solid (i.e., vitrification) and the levitation of droplets on liquid nitrogen (i.e., Leidenfrost phenomenon) take place simultaneously. Here, we investigate these two simultaneous physical events by using a theoretical model containing three dimensionless parameters (i.e., Stefan, Biot, and Fourier numbers). We explain theoretically and observe experimentally a threshold droplet radius during the vitrification of a cryoprotectant droplet in the presence of the Leidenfrost effect.

Vitrification and levitation of a liquid droplet on liquid nitrogen

PubMed Central

Song, Young S.; Adler, Douglas; Xu, Feng; Kayaalp, Emre; Nureddin, Aida; Anchan, Raymond M.; Maas, Richard L.; Demirci, Utkan

2010-01-01

The vitrification of a liquid occurs when ice crystal formation is prevented in the cryogenic environment through ultrarapid cooling. In general, vitrification entails a large temperature difference between the liquid and its surrounding medium. In our droplet vitrification experiments, we observed that such vitrification events are accompanied by a Leidenfrost phenomenon, which impedes the heat transfer to cool the liquid, when the liquid droplet comes into direct contact with liquid nitrogen. This is distinct from the more generally observed Leidenfrost phenomenon that occurs when a liquid droplet is self-vaporized on a hot plate. In the case of rapid cooling, the phase transition from liquid to vitrified solid (i.e., vitrification) and the levitation of droplets on liquid nitrogen (i.e., Leidenfrost phenomenon) take place simultaneously. Here, we investigate these two simultaneous physical events by using a theoretical model containing three dimensionless parameters (i.e., Stefan, Biot, and Fourier numbers). We explain theoretically and observe experimentally a threshold droplet radius during the vitrification of a cryoprotectant droplet in the presence of the Leidenfrost effect. PMID:20176969

Simultaneous observation of chemomechanical coupling of a molecular motor.

PubMed

Nishizaka, Takayuki; Hasimoto, Yuh; Masaike, Tomoko

2011-01-01

F(1)-ATPase is the smallest rotary molecular motor ever found. Unidirectional rotation of the γ-shaft is driven by precisely coordinated sequential ATP hydrolysis reactions in three catalytic sites arranged 120° apart in the cylinder. Single-molecule observation allows us to directly watch the rotation of the shaft using micron-sized plastic beads. Additionally, an advanced version of "total internal reflection fluorescence microscope (TIRFM)" enables us to detect binding and release of energy currency through fluorescently labeled ATP. In this chapter, we describe how to set up the system for simultaneous observation of these two critical events. This specialized optical setup is applicable to a variety of research, not only molecular motors but also other single-molecule topics.

Observational evidence of predawn plasma bubble and its irregularity scales in Southeast Asia

NASA Astrophysics Data System (ADS)

Watthanasangmechai, K.; Tsunoda, R. T.; Yokoyama, T.; Ishii, M.; Tsugawa, T.

2016-12-01

This paper describes an event of deep plasma depletion simultaneously detected with GPS, GNU Radio Beacon Receiver (GRBR) and in situ satellite measurement from DMFPF15. The event is on March 7, 2012 at 4:30 LT with geomagnetic quiet condition. Such a sharp depletion at plasma bubble wall detected at predawn is interesting but apparently rare event. Only one event is found from all dataset in March 2012. The inside structure of the predawn plasma bubble was clearly captured by DMSPF15 and the ground-based GRBR. The envelop structure seen from the precessed GPS-TEC appeares as a cluster. The observed cluster is concluded as the structure at the westwall of an upwelling of the large-scale wave structure, that accompanies the fifty- and thousand-km scales. This event is consistent with the plasma bubble structure simulated from the high-resolution bubble (HIRB) model.

On simultaneous tilt and creep observations on the San Andreas Fault

USGS Publications Warehouse

Johnston, M.J.S.; McHugh, S.; Burford, S.

1976-01-01

THE installation of an array of tiltmeters along the San Andreas Fault 1 has provided an excellent opportunity to study the amplitude and spatial scale of the tilt fields associated with fault creep. We report here preliminary results from, and some implications of, a search for interrelated surface tilts and creep event observations at four pairs of tiltmeters and creepmeters along an active 20-km stretch of the San Andreas Fault. We have observed clear creep-related tilts above the instrument resolution (10 -8 rad) only on a tiltmeter less than 0.5 km from the fault. The tilt events always preceded surface creep observations by 2-12 min, and were not purely transient in character. ?? 1975 Nature Publishing Group.

Conjugate observations of electromagnetic ion cyclotron waves associated with traveling convection vortex events

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Clauer, C. Robert; Gerrard, Andrew J.; Engebretson, Mark J.; Hartinger, Michael D.; Lessard, Marc R.; Matzka, Jürgen; Sibeck, David G.; Singer, Howard J.; Stolle, Claudia; Weimer, Daniel R.; Xu, Zhonghua

2017-07-01

We report on simultaneous observations of electromagnetic ion cyclotron (EMIC) waves associated with traveling convection vortex (TCV) events caused by transient solar wind dynamic pressure (Pd) impulse events. The Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft located near the magnetopause observed radial fluctuations of the magnetopause, and the GOES spacecraft measured sudden compressions of the magnetosphere in response to sudden increases in Pd. During the transient events, EMIC waves were observed by interhemispheric conjugate ground-based magnetometer arrays as well as the GOES spacecraft. The spectral structures of the waves appear to be well correlated with the fluctuating motion of the magnetopause, showing compression-associated wave generation. In addition, the wave features are remarkably similar in conjugate hemispheres in terms of bandwidth, quasiperiodic wave power modulation, and polarization. Proton precipitation was also observed by the DMSP spacecraft during the wave events, from which the wave source region is estimated to be 72°-74° in magnetic latitude, consistent with the TCV center. The confluence of space-borne and ground instruments including the interhemispheric, high-latitude, fluxgate/induction coil magnetometer array allows us to constrain the EMIC source region while also confirming the relationship between EMIC waves and the TCV current system.

GW150914: First results from the search for binary black hole coalescence with Advanced LIGO

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bohémier, K.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Clayton, J. H.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Cokelaer, T.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R. T.; De Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Dietz, A.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fotopoulos, N.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Goggin, L. M.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Keppel, D. G.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McKechan, D. J. A.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messaritaki, E.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Phelps, M.; Piccinni, O.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Robinson, C.; Rocchi, A.; Rodriguez, A. C.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Santamaría, L.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Wiesner, K.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2016-06-01

On September 14, 2015, at 09∶50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) simultaneously observed the binary black hole merger GW150914. We report the results of a matched-filter search using relativistic models of compact-object binaries that recovered GW150914 as the most significant event during the coincident observations between the two LIGO detectors from September 12 to October 20, 2015 GW150914 was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203000 years, equivalent to a significance greater than 5.1 σ .

GW150914: First Results from the Search for Binary Black Hole Coalescence with Advanced LIGO

NASA Technical Reports Server (NTRS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.;

Pseudo-automatic Determination of Coronal Mass Ejections’ Kinematics in 3D

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

Braga, Carlos Roberto; Dal Lago, Alisson; Echer, Ezequiel

Coronal mass ejection (CME) events are among the main drivers of geomagnetic disturbances, and hence play a central role in the Sun–Earth system. Their monitoring and, in particular, the determination of their speed and direction of propagation are key issues for the forecasting of space weather near to Earth. We have implemented a method to track CME events in three dimensions by combining triangulation and tie-pointing analysis with a supervised computer vision algorithm. This novel approach does not rely on any geometric constraint, and eliminates the need for visual identification of the CME boundaries. We applied our method to 17more » CME events observed simultaneously by the twin Solar Terrestrial Relations Observatory ( STEREO ) COR2 coronagraph imagers from 2008 December to 2011 November in order to obtain their 3D kinematical characterization (i.e., the velocity vector) along with their morphological properties. About ten of these events have already been analyzed using other methodologies. In these cases, we carried out a thorough comparison with our results and found that, in spite of the different nature and spatial coverage range of the other methods with respect to CORSET3D, the majority of the results agree. We found, however, that three events exhibited discrepancies in the magnitude of the velocity vector, four in the longitudinal direction of propagation, and in only one case was there a discrepancy in latitude. The discrepancies appeared in those cases where quasi-simultaneous, quasi-co-located events were observed in the coronagraphs’ fields of view.« less

Communication patterns in a UK emergency department.

PubMed

Woloshynowych, Maria; Davis, Rachel; Brown, Ruth; Vincent, Charles

2007-10-01

Good communication is important in patient care and plays an essential part of teamwork and patient safety. Communication in the emergency department (ED) can be chaotic, with the potential for error resulting from communication overload and problems of communication. The nurse in charge of the ED plays a crucial role in maintaining communication flow. The aims of this study are to identify the features of the communication load on the nurse in charge of the ED. This was an observational, nonexperimental study, building on the methods of observation and analysis developed by Coiera. It was carried out in an inner-city hospital ED in London. The nurse in charge of the ED was observed. The following factors were studied: the level of communication, interruptions, and simultaneous events; the channel and purpose of communication; interaction types; unresolved communications and annoying aspects of the observed periods; and the effect of weekday, staffing, and patient levels on the level of communication. Eleven nurses were observed during 18 observation periods during a total of 20 hours. Analysis revealed that there were 2,019 communication events in 20 hours and that 1,183 (59%) were initiated by the nurse in charge. Two hundred eighty-six (14%) simultaneous events/tasks were identified by the observer. One thousand five hundred twenty-eight (76%) communications involving the nurse in charge were face to face, 144 (7%) were by telephone, 107 (5%) concerned the use of the computer, and 104 (5%) concerned the use of the whiteboard. The largest purpose of communication events was related to patient management (48%). There was a slight relationship between junior medical staff and the level of communication and a moderate relationship between communication load and the number of patients in the ED. In addition, a greater number of nurses on duty were associated with fewer communication events with the nurse in charge. These findings are an important measure of communication load, which can disrupt memory and lead to mistakes. Improving communication between health care staff by reducing the levels of interruptions and minimizing the volume of irrelevant or unnecessary information exchange could therefore have important implications for patient safety.

On the connection between the 3HE-enrichment and spectral index of solar energetic particles

NASA Technical Reports Server (NTRS)

Kocharov, L. G.; Dvoryanchikov, Y. V.

1985-01-01

A model is presented which explains the observed tendency of events with large 3He/4He ratios to have steeper spectra. In this model preferential injection of 3He, acceleration by Alfven waves and Coulomb deceleration of ions are considered simultaneously. The observed tendency may be obtained as a result of competition between injection and acceleration processes.

Simultaneous characterization of pancreatic stellate cells and other pancreatic components within three-dimensional tissue environment during chronic pancreatitis

NASA Astrophysics Data System (ADS)

Hu, Wenyan; Fu, Ling

2013-05-01

Pancreatic stellate cells (PSCs) and other pancreatic components that play a critical role in exocrine pancreatic diseases are generally identified separately by conventional studies, which provide indirect links between these components. Here, nonlinear optical microscopy was evaluated for simultaneous characterization of these components within a three-dimensional (3-D) tissue environment, primarily based on multichannel detection of intrinsic optical emissions and cell morphology. Fresh rat pancreatic tissues harvested at 1 day, 7 days, and 28 days after induction of chronic pancreatitis were imaged, respectively. PSCs, inflammatory cells, blood vessels, and collagen fibers were identified simultaneously. The PSCs at day 1 of chronic pancreatitis showed significant enlargement compared with those in normal pancreas (p<0.001, analysis of variance linear contrast; n=8 for each group). Pathological events relating to these components were observed, including presence of inflammatory cells, deposited collagen, and phenotype conversion of PSCs. We demonstrate that label-free nonlinear optical microscopy is an efficient tool for dissecting PSCs and other pancreatic components coincidently within 3-D pancreatic tissues. It is a prospect for intravital observation of dynamic events under natural physiological conditions, and might help uncover the key mechanisms of exocrine pancreatic diseases, leading to more effective treatments.

A General Audiovisual Temporal Processing Deficit in Adult Readers With Dyslexia.

PubMed

Francisco, Ana A; Jesse, Alexandra; Groen, Margriet A; McQueen, James M

2017-01-01

Because reading is an audiovisual process, reading impairment may reflect an audiovisual processing deficit. The aim of the present study was to test the existence and scope of such a deficit in adult readers with dyslexia. We tested 39 typical readers and 51 adult readers with dyslexia on their sensitivity to the simultaneity of audiovisual speech and nonspeech stimuli, their time window of audiovisual integration for speech (using incongruent /aCa/ syllables), and their audiovisual perception of phonetic categories. Adult readers with dyslexia showed less sensitivity to audiovisual simultaneity than typical readers for both speech and nonspeech events. We found no differences between readers with dyslexia and typical readers in the temporal window of integration for audiovisual speech or in the audiovisual perception of phonetic categories. The results suggest an audiovisual temporal deficit in dyslexia that is not specific to speech-related events. But the differences found for audiovisual temporal sensitivity did not translate into a deficit in audiovisual speech perception. Hence, there seems to be a hiatus between simultaneity judgment and perception, suggesting a multisensory system that uses different mechanisms across tasks. Alternatively, it is possible that the audiovisual deficit in dyslexia is only observable when explicit judgments about audiovisual simultaneity are required.

Characteristics of electron distributions observed during large amplitude whistler wave events in the magnetosphere

NASA Astrophysics Data System (ADS)

Wilson, L. B., III; Cattell, C. A.; Kellogg, P. J.; Goetz, K.; Wygant, J.; Breneman, A. W.; Kersten, K.

2010-12-01

We present a statistical study of the characteristics of electron distributions associated with large amplitude whistler waves inside the terrestrial magnetosphere using waveform capture data as an addition of the study by Kellogg et al., [2010b]. We identified three types of electron distributions observed simultaneously with the whistler waves including beam-like, beam/flattop, and anisotropic distributions. The whistlers exhibited different characteristics dependent upon the observed electron distributions. The majority of the waveforms observed in our study have f/fce ≤ 0.5 and are observed primarily in the radiation belts outside the plasmapause simultaneously with anisotropic electron distributions. We also present an example waveform capture of the largest magnetic field amplitude (≥ 8 nT pk-pk) whistler wave measured in the radiation belts. The majority of the largest amplitude whistlers occur during magnetically active periods (AE > 200 nT).

Characteristics of Electron Distributions Observed During Large Amplitude Whistler Wave Events in the Magnetosphere

NASA Technical Reports Server (NTRS)

Wilson, Lynn B., III

2010-01-01

We present a statistical study of the characteristics of electron distributions associated with large amplitude whistler waves inside the terrestrial magnetosphere using waveform capture data as an addition of the study by Kellogg et al., [2010b]. We identified three types of electron distributions observed simultaneously with the whistler waves including beam-like, beam/flattop, and anisotropic distributions. The whistlers exhibited different characteristics dependent upon the observed electron distributions. The majority of the waveforms observed in our study have f/fce < or = 0.5 and are observed primarily in the radiation belts outside the plasmapause simultaneously with anisotropic electron distributions. We also present an example waveform capture of the largest magnetic field amplitude (> or = 8 nT pk-pk) whistler wave measured in the radiation belts. The majority of the largest amplitude whistlers occur during magnetically active periods (AE > 200 nT).

Simultaneous Observations of p-mode Light Walls and Magnetic Reconnection Ejections above Sunspot Light Bridges

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

Hou, Yijun; Zhang, Jun; Li, Ting

Recent high-resolution observations from the Interface Region Imaging Spectrograph reveal bright wall-shaped structures in active regions (ARs), especially above sunspot light bridges. Their most prominent feature is the bright oscillating front in the 1400/1330 Å channel. These structures are named light walls and are often interpreted to be driven by p-mode waves. Above the light bridge of AR 12222 on 2014 December 06, we observed intermittent ejections superimposed on an oscillating light wall in the 1400 Å passband. At the base location of each ejection, the emission enhancement was detected in the Solar Dynamics Observatory 1600 Å channel. Thus, wemore » suggest that in wall bases (light bridges), in addition to the leaked p-mode waves consistently driving the oscillating light wall, magnetic reconnection could happen intermittently at some locations and eject the heated plasma upward. Similarly, in the second event occurring in AR 12371 on 2015 June 16, a jet was simultaneously detected in addition to the light wall with a wave-shaped bright front above the light bridge. At the footpoint of this jet, lasting brightening was observed, implying magnetic reconnection at the base. We propose that in these events, two mechanisms, p-mode waves and magnetic reconnection, simultaneously play roles in the light bridge, and lead to the distinct kinetic features of the light walls and the ejection-like activities, respectively. To illustrate the two mechanisms and their resulting activities above light bridges, in this study we present a cartoon model.« less

Galactic Distribution of Planets From High-Magnification Microlensing Events

NASA Astrophysics Data System (ADS)

Gould, Andrew; Yee, Jennifer; Carey, Sean

2015-10-01

We will use Spitzer to measure microlens parallaxes for ~14 microlensing events that are high-magnification (as seen from Earth), in order to determine the Galactic distribution of planets. Simultaneous observations from Spitzer and Earth yield parallaxes because they are separated by ~1 AU, which is of order the size of the Einstein radius projected on the observer plane. Hence, Earth and Spitzer see substantially different lightcurves for the same event. These Spitzer parallaxes enable measurements of the distances to the lenses (and their masses), which is a crucial element for measuring the Galactic distribution of planets. High-mag events are exceptionally sensitive to planets: Gould+ (2010) detected 6 planets from 13 high-mag events. However, previously it was believed impossible to measure their parallaxes using Spitzer: scheduling constraints imply a 3-10 day delay from event recognition to first observation, while high-mag events are typically recognized only 1-2 days before peak. By combining aggressive observing protocols, a completely new photometry pipeline, and new mathematical techniques, we successfully measured parallaxes for 7 events with peak magnification A>100 and another ~7 with 50

Hypervelocity dust particle impacts observed by the Giotto magnetometer and plasma experiments

NASA Technical Reports Server (NTRS)

Neubauer, F. M.; Glassmeier, K.-H.; Coates, A. J.; Goldstein, R.; Acuna, M. H.

1990-01-01

This paper describes 13 very short events in the magnetic field of the inner magnetic pile-up region of Comet Halley observed by the Giotto magnetometer experiment together with simultaneous plasma data obtained by the Johnstone plasma analyzer and the ion mass spectrometer experiments. The events are due to dust impacts in the milligram range on the spacecraft at the relative velocity between the cometary dust and the spacecraft of 68 km/sec. They are generally consistent with dust impact events derived from spacecraft attitude perturbations by the Giotto camera. Their characteristic shape generally involves a sudden decrease in magnetic-field magnitude, a subsequent overshoot beyond initial field values, and an asymptotic approach to the initial field (somewhat reminiscent of the magnetic-field signature after the AMPTE releases in the solar wind). These observations give a new way of analyzing ultra-fast dust particles incident on a spacecraft.

The evolution of the X-ray afterglow emission of GW 170817/ GRB 170817A in XMM-Newton observations

NASA Astrophysics Data System (ADS)

D'Avanzo, P.; Campana, S.; Salafia, O. S.; Ghirlanda, G.; Ghisellini, G.; Melandri, A.; Bernardini, M. G.; Branchesi, M.; Chassande-Mottin, E.; Covino, S.; D'Elia, V.; Nava, L.; Salvaterra, R.; Tagliaferri, G.; Vergani, S. D.

2018-05-01

We report our observation of the short gamma-ray burst (GRB) GRB 170817A, associated to the binary neutron star merger gravitational wave (GW) event GW 170817, performed in the X-ray band with XMM-Newton 135 d after the event (on 29 December, 2017). We find evidence for a flattening of the X-ray light curve with respect to the previously observed brightening. This is also supported by a nearly simultaneous optical Hubble Space Telescope observation and successive X-ray Chandra and low-frequency radio observations recently reported in the literature. Since the optical-to-X-ray spectral slope did not change with respect to previous observations, we exclude that the change in the temporal evolution of the light curve is due to the passage of the cooling frequency: its origin must be geometric or dynamical. We interpret all the existing afterglow data with two models: i) a structured jet and ii) a jet-less isotropic fireball with some stratification in its radial velocity structure. Both models fit the data and predict that the radio flux must decrease simultaneously with the optical and X-ray emission, making it difficult to distinguish between them at the present stage. Polarimetric measurements and the rate of short GRB-GW associations in future LIGO/Virgo runs will be key to disentangle these two geometrically different scenarios.

Temporal and Spatial Predictability of an Irrelevant Event Differently Affect Detection and Memory of Items in a Visual Sequence

PubMed Central

Ohyama, Junji; Watanabe, Katsumi

2016-01-01

We examined how the temporal and spatial predictability of a task-irrelevant visual event affects the detection and memory of a visual item embedded in a continuously changing sequence. Participants observed 11 sequentially presented letters, during which a task-irrelevant visual event was either present or absent. Predictabilities of spatial location and temporal position of the event were controlled in 2 × 2 conditions. In the spatially predictable conditions, the event occurred at the same location within the stimulus sequence or at another location, while, in the spatially unpredictable conditions, it occurred at random locations. In the temporally predictable conditions, the event timing was fixed relative to the order of the letters, while in the temporally unpredictable condition; it could not be predicted from the letter order. Participants performed a working memory task and a target detection reaction time (RT) task. Memory accuracy was higher for a letter simultaneously presented at the same location as the event in the temporally unpredictable conditions, irrespective of the spatial predictability of the event. On the other hand, the detection RTs were only faster for a letter simultaneously presented at the same location as the event when the event was both temporally and spatially predictable. Thus, to facilitate ongoing detection processes, an event must be predictable both in space and time, while memory processes are enhanced by temporally unpredictable (i.e., surprising) events. Evidently, temporal predictability has differential effects on detection and memory of a visual item embedded in a sequence of images. PMID:26869966

Temporal and Spatial Predictability of an Irrelevant Event Differently Affect Detection and Memory of Items in a Visual Sequence.

PubMed

Ohyama, Junji; Watanabe, Katsumi

2016-01-01

We examined how the temporal and spatial predictability of a task-irrelevant visual event affects the detection and memory of a visual item embedded in a continuously changing sequence. Participants observed 11 sequentially presented letters, during which a task-irrelevant visual event was either present or absent. Predictabilities of spatial location and temporal position of the event were controlled in 2 × 2 conditions. In the spatially predictable conditions, the event occurred at the same location within the stimulus sequence or at another location, while, in the spatially unpredictable conditions, it occurred at random locations. In the temporally predictable conditions, the event timing was fixed relative to the order of the letters, while in the temporally unpredictable condition; it could not be predicted from the letter order. Participants performed a working memory task and a target detection reaction time (RT) task. Memory accuracy was higher for a letter simultaneously presented at the same location as the event in the temporally unpredictable conditions, irrespective of the spatial predictability of the event. On the other hand, the detection RTs were only faster for a letter simultaneously presented at the same location as the event when the event was both temporally and spatially predictable. Thus, to facilitate ongoing detection processes, an event must be predictable both in space and time, while memory processes are enhanced by temporally unpredictable (i.e., surprising) events. Evidently, temporal predictability has differential effects on detection and memory of a visual item embedded in a sequence of images.

The Search for Transient Mass Loss Events on Active Stars and Their Impacts

NASA Astrophysics Data System (ADS)

Crosley, Michael K.

2018-01-01

The conditions that determine the potential habitability of exoplanets are very diverse and still poorly understood. Magnetic eruptive events, such as flares and coronal mass ejections (CME's) are one such concern. Stellar flares are routinely observed and on cool stars but clear signatures of stellar CME's have been less forthcoming. CME’s are geoeffective and contribute to space weather. Stellar coronal mass ejections remain experimentally unconstrained, unlike the stellar flare counterpart which are observed ubiquitously across the electromagnetic spectrum. Low frequency radio bursts in the form of a type II burst offer the best means of identifying and constraining the rate and properties of stellar CME’s. CME properties can be further constrained and solar scaling relationships tested by simultaneously preforming flare observations. The interpretation for the multi-wavelength analysis of type II events and their associated flares is tested by fully constrained solar observations. There we find that velocity measurements are typically accurate to within a factor of two and that mass constraints are accurate to within an order of magnitude. We take these lessons and apply them to observations of the nearby, active M dwarf stars YZ Cmi and EQ Peg. These stars have the advantage of being well observed and constrained. Their well documented high flare activity is expected to be accompanied with high CME activity. They have been shown to have low frequency radio bursts in the past, and their constrained coronal properties allows us to extract the information required to interpret the type II burst. We report on 15 hours of Low Frequency Array (10-190 MHz) observations of YZ Cmi and to 64 hours of EQ Peg observations at the Jansky Very Large Array (230-470 MHz), 20 hours of which were observed simultaneously for flares at the Apache Point Observatory. During this time, solar scaling relationships tells us that ~70 large flares should have been produced which would be associated to a corresponding CME as well. From our results we can constraint event properties, detection limits, CME models, and atmospheric models.

Action at the Horizon: Chandra/EHT Observations of Sgr A*

NASA Astrophysics Data System (ADS)

Neilsen, Joseph

2017-09-01

In April 2017, the Event Horizon Telescope will observe Sgr A* with imaging quality sufficient to resolve the shadow of the black hole, while providing a close-up view of accretion at the horizon. As Sgr A* is a well-known source of X-ray flares, coordinated Chandra/EHT observations offer an incredible opportunity: a chance to observe structures (e.g., hotspots) near the event horizon while tracking their high-energy variability. In anticipation of a follow-up campaign in 2018, we are requesting 4x33 ks Chandra observations of Sgr A* to be coordinated with EHT. This campaign will double our chances of simultaneous flares. We will search for flares and hotspots, provide priors for EHT image reconstruction, and track any activity associated with the closest approach of the massive star S0-2.

Simultaneous observations of subauroral electron temperature enhancements and electromagnetic ion cyclotron waves

NASA Technical Reports Server (NTRS)

Erlandson, R. E.; Aggson, T. L.; Hogey, W. R.; Slavin, J. A.

1993-01-01

Observational results from an investigation of LF (0.5-4.0 Hz) electromagnetic ion cyclotron waves and subauroral electron temperature enhancements recorded from the DE-2 satellite are presented. Four different wave events were analyzed, all recorded at magnetic latitudes from 57-60 deg, magnetic local times from 8-14 hr, and altitudes from 600-900 km. The peak wave amplitudes during the events ranged from 8-70 nT and 5-30 mV/m in the magnetic and electric field, respectively. Te enhancements at the time of the waves were observed in three of four events. A linear relationship between the wave magnetic field spectral density and Te enhancements was found for these events. The Te enhancements were also correlated with an enhanced flux of low energy electrons. During one event (82104) an enhanced flux of electrons were observed at energies up to 50 eV and at nearly all pitch angles, although the flux was largest in the precipitating and upflowing directions. It is suggested that the waves are responsible for heating the low energy electrons which precipitate to the ionosphere and produce the observed Te enhancements. The upflowing electron population appears to be heated at ionospheric altitudes, below the DE-2 satellite.

Properties of arctic haze aerosol from lidar observations during iarea 2015 campaign on spitsbergen

NASA Astrophysics Data System (ADS)

Stachlewska, Iwona S.; Ritter, Christoph; Böckmann, Christine; Engelmann, Ronny

2018-04-01

Arctic Haze event was observed on 5-8 April 2015 using simultaneously Near-range Aerosol Raman Lidar of IGFUW and Koldewey Aerosol Raman Lidar of AWI, both based at AWIPEV German-French station in Ny-Ålesund, Spitsbergen. The alterations in particle abundance and altitude of the aerosol load observed on following days of the event is analyzed. The daytime profiles of particle optical properties were obtained for both lidars, and then served as input for microphysical parameters inversion. The results indicate aerosol composition typical for the Arctic Haze. However, in some layers, a likely abundance of aqueous aerosol or black carbon originating in biomass burning over Siberia, changes measurably the Arctic Haze properties.

Simultaneous Traveling Convection Vortex (TCV) Events and Pc 1-2 Wave Bursts at Cusp/Cleft Latitudes observed in Arctic Canada and Svalbard

NASA Astrophysics Data System (ADS)

Posch, J. L.; Witte, A. J.; Engebretson, M. J.; Murr, D.; Lessard, M.; Raita, T.; Singer, H. J.

2010-12-01

Traveling convection vortices (TCVs), which appear in ground magnetometer records at near-cusp latitudes as solitary ~5 mHz pulses, are now known to originate in instabilities in the ion foreshock just upstream of Earth’s bow shock. They can also stimulate compressions or relaxations of the dayside magnetosphere (evident in geosynchronous satellite data). These transient compressions can in turn sharply increase the growth rate of electromagnetic ion cyclotron (EMIC) waves, which also appear in ground records at near-cusp latitudes as bursts of Pc 1-2 pulsations. In this study we have identified simultaneous TCV - Pc 1-2 burst events occurring from 2008 through the first 7 months of 2010 in Eastern Arctic Canada and Svalbard, using a combination of fluxgate magnetometers (MACCS and IMAGE) and search coil magnetometers in each region. Magnetometer observations at GOES 10 and 12, at longitudes near the MACCS sites, are also used to characterize the strength of the magnetic perturbations. There is no direct proportion between the amplitude of TCV and Pc 1-2 wave events in either region, consistent with the highly variable densities and pitch angle distributions of plasma of ring current / plasma sheet energies in the outer dayside magnetosphere.

Nanohole Arrays of Mixed Designs and Microwriting for Simultaneous and Multiple Protein Binding Studies

PubMed Central

Ji, Jin; Yang, Jiun-Chan; Larson, Dale N.

2009-01-01

We demonstrate using nanohole arrays of mixed designs and a microwriting process based on dip-pen nanolithography to monitor multiple, different protein binding events simultaneously in real time based on the intensity of Extraordinary Optical Transmission of nanohole arrays. The microwriting process and small footprint of the individual nanohole arrays enabled us to observe different binding events located only 16μm apart, achieving high spatial resolution. We also present a novel concept that incorporates nanohole arrays of different designs to improve confidence and accuracy of binding studies. For proof of concept, two types of nanohole arrays, designed to exhibit opposite responses to protein bindings, were fabricated on one transducer. Initial studies indicate that the mixed designs could help to screen out artifacts such as protein intrinsic signals, providing improved accuracy of binding interpretation. PMID:19297143

Ka-band and X-band observations of the solar corona acquired during the Cassini 2001 superior conjunction

NASA Technical Reports Server (NTRS)

Morabito, D. D.

2002-01-01

Simultaneous dual-frequency Ka-band (32 GHz) and X-band (8.4 GHz) carrier signal data have been acquired during the superior conjunction of the Cassini spacecraft June 2001, using the NASA Deep Space Network's facilities located in Goldstone, California. The solar elongation angle of the observations varied from -4.1 degrees (-16 solar radii) to -0.6 degrees (-2.3 solar radii). The observed coronal and solar effects on the signals include spectral broadening, amplitude scintillation, phase scintillation, and increased noise. The measurements were generally consistent with existing solar models, except during solar transient events when the signatures of the measurements were observed to increase significantly above the quiet background levels. This is the second solar conjunction of Cassini for which simultaneous X/Ka data were acquired. Both solar conjunctions, conducted in May 2000 and June 2001, occurred near the peak of the current 11 year solar cycle.

Improving Functional Magnetic Resonance Imaging Motor Studies Through Simultaneous Electromyography Recordings

PubMed Central

MacIntosh, Bradley J.; Baker, S. Nicole; Mraz, Richard; Ives, John R.; Martel, Anne L.; McIlroy, William E.; Graham, Simon J.

2016-01-01

Specially designed optoelectronic and data postprocessing methods are described that permit electromyography (EMG) of muscle activity simultaneous with functional MRI (fMRI). Hardware characterization and validation included simultaneous EMG and event-related fMRI in 17 healthy participants during either ankle (n = 12), index finger (n = 3), or wrist (n = 2) contractions cued by visual stimuli. Principal component analysis (PCA) and independent component analysis (ICA) were evaluated for their ability to remove residual fMRI gradient-induced signal contamination in EMG data. Contractions of ankle tibialis anterior and index finger abductor were clearly distinguishable, although observing contractions from the wrist flexors proved more challenging. To demonstrate the potential utility of simultaneous EMG and fMRI, data from the ankle experiments were analyzed using two approaches: 1) assuming contractions coincided precisely with visual cues, and 2) using EMG to time the onset and offset of muscle contraction precisely for each participant. Both methods produced complementary activation maps, although the EMG-guided approach recovered more active brain voxels and revealed activity better in the basal ganglia and cerebellum. Furthermore, numerical simulations confirmed that precise knowledge of behavioral responses, such as those provided by EMG, are much more important for event-related experimental designs compared to block designs. This simultaneous EMG and fMRI methodology has important applications where the amplitude or timing of motor output is impaired, such as after stroke. PMID:17133382

Improving functional magnetic resonance imaging motor studies through simultaneous electromyography recordings.

PubMed

MacIntosh, Bradley J; Baker, S Nicole; Mraz, Richard; Ives, John R; Martel, Anne L; McIlroy, William E; Graham, Simon J

2007-09-01

Specially designed optoelectronic and data postprocessing methods are described that permit electromyography (EMG) of muscle activity simultaneous with functional MRI (fMRI). Hardware characterization and validation included simultaneous EMG and event-related fMRI in 17 healthy participants during either ankle (n = 12), index finger (n = 3), or wrist (n = 2) contractions cued by visual stimuli. Principal component analysis (PCA) and independent component analysis (ICA) were evaluated for their ability to remove residual fMRI gradient-induced signal contamination in EMG data. Contractions of ankle tibialis anterior and index finger abductor were clearly distinguishable, although observing contractions from the wrist flexors proved more challenging. To demonstrate the potential utility of simultaneous EMG and fMRI, data from the ankle experiments were analyzed using two approaches: 1) assuming contractions coincided precisely with visual cues, and 2) using EMG to time the onset and offset of muscle contraction precisely for each participant. Both methods produced complementary activation maps, although the EMG-guided approach recovered more active brain voxels and revealed activity better in the basal ganglia and cerebellum. Furthermore, numerical simulations confirmed that precise knowledge of behavioral responses, such as those provided by EMG, are much more important for event-related experimental designs compared to block designs. This simultaneous EMG and fMRI methodology has important applications where the amplitude or timing of motor output is impaired, such as after stroke. (c) 2006 Wiley-Liss, Inc.

Simultaneous Study of Mechanical Stretch-Induced Cell Proliferation and Apoptosis on C2C12 Myoblasts.

PubMed

Feng, Yu; Tian, Xiang-Yang; Sun, Peng; Cheng, Ze-Peng; Shi, Reng-Fei

2018-06-27

Mechanical stretch may cause myoblasts to either proliferate or undergo apoptosis. Identifying the molecular events that switch the fate of a stretched cell from proliferation to apoptosis is practically important in the field of regenerative medicine. A recent study on vascular smooth muscle cells illustrated that identification of these events may be achieved by addressing the stretch-induced opposite cellular outcomes simultaneously within a single investigation. To define conditions or a model in which both proliferation and apoptosis can be studied at the same time, we exposed in vitro cultured C2C12 myoblasts to a cyclic mechanical stretch regimen of 15% elongation at a stretching frequency of 1 Hz for 0, 2, 4, 6, or 8 h every day, consecutively, for 3 days. Both proliferation and apoptosis were observed. Moreover, as the duration of the stretch was prolonged, cell proliferation increased until it peaked at the optimal stretching duration. Afterwards, apoptosis gradually prevailed. Therefore, we established a model in which stretch-induced cell proliferation and apoptosis can be studied simultaneously. © 2018 S. Karger AG, Basel.

A multi-wavelength study of pre-main sequence stars in the Taurus-Auriga star-forming region

NASA Astrophysics Data System (ADS)

Guenther, E. W.; Stelzer, B.; Neuhäuser, R.; Hillwig, T. C.; Durisen, R. H.; Menten, K. M.; Greimel, R.; Barwig, H.; Englhauser, J.; Robb, R. M.

2000-05-01

Although many lowmass pre-main sequence stars are strong X-ray sources, the origin of the X-ray emission is not well known. Since these objects are variable at all frequencies, simultaneous observations in X-rays and in other wavelengths are able to constrain the properties of the X-ray emitting regions. In this paper, we report quasi-simultaneous observations in X-rays, the optical, and the radio regime for classical and weak-line T Tauri stars from the Taurus-Auriga star-forming region. We find that all detected T Tauri stars show significant night-to-night variations of the X-ray emission. For three of the stars, FM Tau and CW Tau, both classical T Tauri stars, and V773 Tau, a weak-line T Tauri star, the variations are especially large. From observations taken simultaneously, we also find that there is some correspondence between the strength of Hα and the X-ray brightness in V773 Tau. The lack of a strong correlation leads us to conclude that the X-ray emission of V773 Tau is not a superposition of flares. However, we suggest that a weak correlation occurs because chromospherically active regions and regions of strong X-ray emission are generally related. V773 Tau was detected at 8.46 GHz as a weakly circularly polarised but highly variable source. We also find that the X-ray emission and the equivalent width of Hα remained unchanged, while large variations of the flux density in the radio regime were observed. This clearly indicates that the emitting regions are different. Using optical spectroscopy we detected a flare in Hα and event which showed a flare-like light-curve of the continuum brightness in FM Tau. However, ROSAT did not observe the field at the times of these flares. Nevertheless, an interesting X-ray event was observed in V773 Tau, during which the flux increased for about 8 hours and then decreased back to the same level in 5 hours. We interpret this as a long-duration event similar to those seen on the sun and other active stars. In the course of the observations, we discovered a new weak-line T Tauri star, GSC-1839-5674. Results are also presented for several other stars in the ROSAT field.

Beaming Structures of Jupiter's Decametric Radiation from LWA1, NDA, and URAN2 Simultaneous Observations

NASA Astrophysics Data System (ADS)

Imai, M.; Lecacheux, A.; Higgins, C. A.; Clarke, T.; Panchenko, M.; Brazhenko, A. I.; Frantsuzenko, A. V.; Konovalenko, A. A.; Imai, K.

2015-12-01

From December 2014 to March 2015, Jupiter's decametric (DAM) radio observations were carried out by using simultaneously three powerful low-frequency radio telescopes: Long Wavelength Array One (LWA1), Socorro, USA; Nançay Decameter Array (NDA), Nançay, France; and URAN2 telescope, Poltava, Ukraine. Baselines are 10000, 8600, and 2400 kilometers for LWA1-URAN2, NDA-LWA1, and URAN2-NDA, respectively. One Io-B and two Io-A emissions were simultaneously observed. Using cross-correlation analysis of obtained spectrograms, it was found that, as a function of lag time in a pair of two stations, Io-B (mainly S-bursts) and Io-A (L-bursts) show different kinds of cross-correlation coefficients, with sharp and broad peaks, respectively. By measuring lag times between LWA1-URAN2, NDA-LWA1, and URAN2-NDA pairs, it can be tested if either flashlight- or beacon-like beaming is emanated from Jupiter. Measurements of beaming width are also analyzed. Most probable beaming scenarios for Io-B and -A events are suggested.

Case study of simultaneous observations of sporadic sodium layer, E-region field-aligned irregularities and sporadic E layer at low latitude of China

NASA Astrophysics Data System (ADS)

Xie, H. Y.; Ning, B. Q.; Zhao, X. K.; Hu, L. H.

2017-03-01

Using the Na lidar at Haikou (20.0°N, 110.3°E), the VHF coherent radar and the digital ionosonde both at Sanya (18.4°N, 109.6°E), cases of simultaneous observations of sporadic sodium layer (SSL), E-region field-aligned irregularities (FAI) and sporadic E layer (Es) in the mesosphere and lower thermosphere (MLT) region at low latitude of China are studied. It is found that SSL occurs simultaneously or follows the enhancement of Es and FAI. The Es, FAI and SSL descend slowly with time which is mostly controlled by the diurnal tide (DT). Besides, the interaction of gravity wave (GW) with tides can cause oscillations in FAI and SSL. Our observations support the neutralization of ions for SSL formation: when the metallic ions layer descents to the altitudes where models predict, the sodium ions convert rapidly to atomic Na that may form an SSL event. Moreover, the SSL peak density will increase (decrease) in the convergence (divergence) vertical shear region of zonal wind.

The Attentional Boost Effect: Transient increases in attention to one task enhance performance in a second task.

PubMed

Swallow, Khena M; Jiang, Yuhong V

2010-04-01

Recent work on event perception suggests that perceptual processing increases when events change. An important question is how such changes influence the way other information is processed, particularly during dual-task performance. In this study, participants monitored a long series of distractor items for an occasional target as they simultaneously encoded unrelated background scenes. The appearance of an occasional target could have two opposite effects on the secondary task: It could draw attention away from the second task, or, as a change in the ongoing event, it could improve secondary task performance. Results were consistent with the second possibility. Memory for scenes presented simultaneously with the targets was better than memory for scenes that preceded or followed the targets. This effect was observed when the primary detection task involved visual feature oddball detection, auditory oddball detection, and visual color-shape conjunction detection. It was eliminated when the detection task was omitted, and when it required an arbitrary response mapping. The appearance of occasional, task-relevant events appears to trigger a temporal orienting response that facilitates processing of concurrently attended information (Attentional Boost Effect). Copyright 2009 Elsevier B.V. All rights reserved.

The Attentional Boost Effect: Transient Increases in Attention to One Task Enhance Performance in a Second Task

PubMed Central

Swallow, Khena M.; Jiang, Yuhong V.

2009-01-01

Recent work on event perception suggests that perceptual processing increases when events change. An important question is how such changes influence the way other information is processed, particularly during dual-task performance. In this study, participants monitored a long series of distractor items for an occasional target as they simultaneously encoded unrelated background scenes. The appearance of an occasional target could have two opposite effects on the secondary task: It could draw attention away from the second task, or, as a change in the ongoing event, it could improve secondary task performance. Results were consistent with the second possibility. Memory for scenes presented simultaneously with the targets was better than memory for scenes that preceded or followed the targets. This effect was observed when the primary detection task involved visual feature oddball detection, auditory oddball detection, and visual color-shape conjunction detection. It was eliminated when the detection task was omitted, and when it required an arbitrary response mapping. The appearance of occasional, task-relevant events appears to trigger a temporal orienting response that facilitates processing of concurrently attended information (Attentional Boost Effect). PMID:20080232

Analysis of magnetometer data/wave signals in the Earth's magnetosphere

NASA Technical Reports Server (NTRS)

Engebretson, Mark J.

1993-01-01

Work on the reduction and analysis of Dynamics Explorer (DE) satellite magnetometer data with special emphasis on the ULF fluctuations and waves evident in such data is described. Research focused on the following: (1) studies of Pc 1 wave packets near the plasmapause; (2) satellite-ground pulsation study; (3) support for studies of ion energization processes; (4) search for Pc 1 wave events in 1981 DE 1 data; (5) study of Pc 3-5 events observed simultaneously by DE 1 and by AMPTE CCE; (6) support for studies of electromagnetic transients on DE 1; and (7) analysis of wave events induced by sudden impulses.

A case study of lightning, whistlers, and associated ionospheric effects during a substorm particle injection event

NASA Technical Reports Server (NTRS)

Rodriguez, J. V.; Inan, U. S.; Li, Y. Q.; Holzworth, R. H.; Smith, A. J.; Orville, R. E.; Rosenberg, T. J.

1992-01-01

The relationships among cloud-to-ground (CG) lightning, sferics, whistlers, VLF amplitude perturbations, and other ionospheric phenomena occurring during substorm events were investigated using data from simultaneous ground-based observations of narrow-band and broad-band VLF radio waves and of CG lightning made during the 1987 Wave-Induced Particle Precipitation campaign conducted from Wallops Island (Virginia). Results suggest that the data collected on ionospheric phenomena during this event may represent new evidence of direct coupling of lightning energy to the lower ionosphere, either in conjunction with or in the absence of gyroresonant interactions between whistler mode waves and electrons in the magnetosphere.

The Mysterious Dimmings of the T Tauri Star V1334 Tau

NASA Astrophysics Data System (ADS)

Rodriguez, Joseph E.; Zhou, George; Cargile, Phillip A.; Stevens, Daniel J.; Osborn, Hugh P.; Shappee, Benjamin J.; Reed, Phillip A.; Lund, Michael B.; Relles, Howard M.; Latham, David W.; Eastman, Jason; Stassun, Keivan G.; Bieryla, Allyson; Esquerdo, Gilbert A.; Berlind, Perry; Calkins, Michael L.; Vanderburg, Andrew; Gaidos, Eric; Ansdell, Megan; Siverd, Robert J.; Beatty, Thomas G.; Kochanek, Christopher S.; Pepper, Joshua; Gaudi, B. Scott; West, Richard G.; Pollacco, Don; James, David; Kuhn, Rudolf B.; Stanek, Krzysztof Z.; Holoien, Thomas W.-S.; Prieto, Jose L.; Johnson, Samson A.; Sergi, Anthony; McCrady, Nate; Johnson, John A.; Wright, Jason T.; Wittenmyer, Robert A.; Horner, Jonathan

2017-02-01

We present the discovery of two extended ˜0.12 mag dimming events of the weak-lined T Tauri star V1334. The start of the first event was missed but came to an end in late 2003, and the second began in 2009 February, and continues as of 2016 November. Since the egress of the current event has not yet been observed, it suggests a period of >13 years if this event is periodic. Spectroscopic observations suggest the presence of a small inner disk, although the spectral energy distribution shows no infrared excess. We explore the possibility that the dimming events are caused by an orbiting body (e.g., a disk warp or dust trap), enhanced disk winds, hydrodynamical fluctuations of the inner disk, or a significant increase in the magnetic field flux at the surface of the star. We also find a ˜0.32 day periodic photometric signal that persists throughout the 2009 dimming which appears to not be due to ellipsoidal variations from a close stellar companion. High-precision photometric observations of V1334 Tau during K2 campaign 13, combined with simultaneous photometric and spectroscopic observations from the ground, will provide crucial information about the photometric variability and its origin.

Models of tremor and low-frequency earthquake swarms on Montserrat

NASA Astrophysics Data System (ADS)

Neuberg, J.; Luckett, R.; Baptie, B.; Olsen, K.

2000-08-01

Recent observations from Soufrière Hills volcano in Montserrat reveal a wide variety of low-frequency seismic signals. We discuss similarities and differences between hybrid earthquakes and long-period events, and their role in explosions and rockfall events. These events occur usually in swarms, and occasionally merge into tremor, an observation that can shed further light on the generation and composition of harmonic tremor. We use a 2D finite difference method to model major features of low-frequency seismic signatures and compare them with the observations. A depth-dependent velocity model for a fluid-filled conduit is introduced which accounts for the varying gas-content in the magma, and the impact on the seismic signals is discussed. We carefully analyse episodes of tremor that show shifting spectral lines and model those in terms of changes in the gas content of the magma as well as in terms of a time-dependent triggering mechanism of low-frequency resonances. In this way we explain the simultaneous occurrence of low-frequency events and tremor with a spectral content comprising integer harmonics.

Exceptional aerosol pollution plume observed using a new ULA-lidar approach

NASA Astrophysics Data System (ADS)

Chazette, Patrick

2016-09-01

An exceptional particulate pollution event was sampled in June 2005 over the Ardèche region in Southern France. Airborne (at the wavelength of 355 nm) and ground-based (at the wavelength of 532 nm) lidars performed measurements simultaneously. Airborne observations were performed from an ultra-light aircraft (ULA); they offer an opportunity to test a new method for inversing lidar profiles which enables their quantitative use while the airplane flies in a scattering layer. Using the results of this approach and the ground-based lidar measurements, the aerosol plumes have been optically quantified and the diversity of particle sources (from Western Europe, North Africa and even North America) which contributed to the event has been highlighted using both spaceborne observations and multiple air mass back-trajectories.

Observation and theory of Pc 5 waves with harmonically related transverse and compressional components

NASA Astrophysics Data System (ADS)

Takahashi, K.; Cheng, C. Z.; McEntire, R. W.; Kistler, L. M.

1990-02-01

The properties of 23 magnetic pulsation events observed by the AMPTE CCE spacecraft are studied. These events are selected on the basis of the field magnitude which oscillated at the second harmonic of a simultaneously present transverse oscillation. The events have a second harmonic period of 80-600 s (roughly the Pc 5 range), are observed in cluster in the dawn (0300-0800 magnetic local time, MLT) and dusk (1600-2100 MLT) sectors, and are localized near the magnetic equator. Although the azimuthal wave number estimated from an ion finite Larmor radius effect, is generally large (about 50), there is a marked difference between the events observed in the dawn and dusk sectors. In the dawn sector the waves have low frequencies (1-5 mHz), indicate left-hand polarization with respect to the ambient magnetic field, and propagate eastward with respect to the spacecraft. In the dusk sector the waves have high frequencies (5-15 mHz), indicate right-hand polarization, and propagate westward. It is suggested that the waves are all westward propagating in the plasma rest frame and that local-time-dependent Doppler shift is the reason for the local time dependence of the wave properties.

Observation and theory of Pc 5 waves with harmonically related transverse and compressional components

NASA Technical Reports Server (NTRS)

Takahashi, K.; Mcentire, R. W.; Cheng, C. Z.; Kistler, L. M.

1990-01-01

The properties of 23 magnetic pulsation events observed by the AMPTE CCE spacecraft are studied. These events are selected on the basis of the field magnitude which oscillated at the second harmonic of a simultaneously present transverse oscillation. The events have a second harmonic period of 80-600 s (roughly the Pc 5 range), are observed in cluster in the dawn (0300-0800 magnetic local time, MLT) and dusk (1600-2100 MLT) sectors, and are localized near the magnetic equator. Although the azimuthal wave number estimated from an ion finite Larmor radius effect, is generally large (about 50), there is a marked difference between the events observed in the dawn and dusk sectors. In the dawn sector the waves have low frequencies (1-5 mHz), indicate left-hand polarization with respect to the ambient magnetic field, and propagate eastward with respect to the spacecraft. In the dusk sector the waves have high frequencies (5-15 mHz), indicate right-hand polarization, and propagate westward. It is suggested that the waves are all westward propagating in the plasma rest frame and that local-time-dependent Doppler shift is the reason for the local time dependence of the wave properties.

Inverted-V events simultaneously observed with the Freja satellite and from the ground

NASA Astrophysics Data System (ADS)

Haerendel, G.; Frey, H. U.; Bauer, O. H.; Rieger, E.; Clemmons, J.; Boehm, M. H.; Wallis, D. D.; Lühr, H.

The paper reports data received from the Freja satellite during two passes over broad auroral arc systems or inverted-V events above Gillam/Manitoba when special wide-angle CCD cameras were operated at this location in addition to the CANOPUS network. Detailed comparisons of the visible structures with modulations of the primary electron fluxes are performed. Motions of this fine structures are interpreted in terms of high-altitude electric fields shielded from the lower ionosphere. Simultaneous readings of current density, accelerating voltage and energy flux, the latter determined both from particle and auroral brightness measurements, are found to be internally consistent. We calculate from these data the effective resistance encountered by the electric currents and find agreement with the kinetic theory of the mirror impedance, if we allow for substantial variations in density and energy of the source electrons in the magnetosphere.

Adaptively Adjusted Event-Triggering Mechanism on Fault Detection for Networked Control Systems.

PubMed

Wang, Yu-Long; Lim, Cheng-Chew; Shi, Peng

2016-12-08

This paper studies the problem of adaptively adjusted event-triggering mechanism-based fault detection for a class of discrete-time networked control system (NCS) with applications to aircraft dynamics. By taking into account the fault occurrence detection progress and the fault occurrence probability, and introducing an adaptively adjusted event-triggering parameter, a novel event-triggering mechanism is proposed to achieve the efficient utilization of the communication network bandwidth. Both the sensor-to-control station and the control station-to-actuator network-induced delays are taken into account. The event-triggered sensor and the event-triggered control station are utilized simultaneously to establish new network-based closed-loop models for the NCS subject to faults. Based on the established models, the event-triggered simultaneous design of fault detection filter (FDF) and controller is presented. A new algorithm for handling the adaptively adjusted event-triggering parameter is proposed. Performance analysis verifies the effectiveness of the adaptively adjusted event-triggering mechanism, and the simultaneous design of FDF and controller.

Episode-Based Evolution Pattern Analysis of Haze Pollution: Method Development and Results from Beijing, China.

PubMed

Zheng, Guangjie; Duan, Fengkui; Ma, Yongliang; Zhang, Qiang; Huang, Tao; Kimoto, Takashi; Cheng, Yafang; Su, Hang; He, Kebin

2016-05-03

Haze episodes occurred in Beijing repeatedly in 2013, resulting in 189 polluted days. These episodes differed in terms of sources, formation processes, and chemical composition and thus required different control policies. Therefore, an overview of the similarities and differences among these episodes is needed. For this purpose, we conducted one-year online observations and developed a program that can simultaneously divide haze episodes and identify their shapes. A total of 73 episodes were identified, and their shapes were linked with synoptic conditions. Pure-haze events dominated in wintertime, whereas mixed haze-dust (PM2.5/PM10 < 60%) and mixed haze-fog (Aerosol Water/PM2.5 ∼ 0.3) events dominated in spring and summer-autumn, respectively. For all types, increase of ratio of PM2.5 in PM10 was typically achieved before PM2.5 reached ∼150 μg/m(3). In all PM2.5 species observed, organic matter (OM) was always the most abundant component (18-60%), but it was rarely the driving factor: its relative contribution usually decreased as the pollution level increased. The only OM-driven episode observed was associated with intensive biomass-burning activities. In comparison, haze evolution generally coincided with increasing sulfur and nitrogen oxidation ratios (SOR and NOR), indicating the enhanced production of secondary inorganic species. Applicability of these conclusions required further tests with simultaneously multisite observations.

Simultaneous optical and IR photometry of the T Tauri star RU LUPI

NASA Astrophysics Data System (ADS)

Giovannelli, F.; Errico, L.; Vittone, A. A.; Rossi, C.

1991-01-01

Two simultaneous optical and IR photometric observation runs of RU Lupi were carried out at the ESO in February 1983 and in June 1986 within the framework of a large multifrequency coordinated campaign of observations. RU Lupi was found in two different states. In the first case the star was in 'quiescence', in the second it was brighter and showed larger variations due to flare like event (FLE). A positive correlation between luminosity and its variations has been found. A Fourier analysis of the light curve available in literature was performed to point out the rotational period. The analysis of these data excludes any periodicity. The color-color diagnostic diagram clearly shows that RU Lupi variability is mainly due to a strong photospheric and chromospheric activity.

Multi-viewpoint Coronal Mass Ejection Catalog Based on STEREO COR2 Observations

NASA Astrophysics Data System (ADS)

Vourlidas, Angelos; Balmaceda, Laura A.; Stenborg, Guillermo; Dal Lago, Alisson

2017-04-01

We present the first multi-viewpoint coronal mass ejection (CME) catalog. The events are identified visually in simultaneous total brightness observations from the twin SECCHI/COR2 coronagraphs on board the Solar Terrestrial Relations Observatory mission. The Multi-View CME Catalog differs from past catalogs in three key aspects: (1) all events between the two viewpoints are cross-linked, (2) each event is assigned a physics-motivated morphological classification (e.g., jet, wave, and flux rope), and (3) kinematic and geometric information is extracted semi-automatically via a supervised image segmentation algorithm. The database extends from the beginning of the COR2 synoptic program (2007 March) to the end of dual-viewpoint observations (2014 September). It contains 4473 unique events with 3358 events identified in both COR2s. Kinematic properties exist currently for 1747 events (26% of COR2-A events and 17% of COR2-B events). We examine several issues, made possible by this cross-linked CME database, including the role of projection on the perceived morphology of events, the missing CME rate, the existence of cool material in CMEs, the solar cycle dependence on CME rate, speeds and width, and the existence of flux rope within CMEs. We discuss the implications for past single-viewpoint studies and for Space Weather research. The database is publicly available on the web including all available measurements. We hope that it will become a useful resource for the community.

High Definition Transcranial Direct Current Stimulation Induces Both Acute and Persistent Changes in Broadband Cortical Synchronization: a Simultaneous tDCS-EEG Study

PubMed Central

Roy, Abhrajeet; Baxter, Bryan

2014-01-01

The goal of this study was to develop methods for simultaneously acquiring electrophysiological data during high definition transcranial direct current stimulation (tDCS) using high resolution electroencephalography (EEG). Previous studies have pointed to the after effects of tDCS on both motor and cognitive performance, and there appears to be potential for using tDCS in a variety of clinical applications. However, little is known about the real-time effects of tDCS on rhythmic cortical activity in humans due to the technical challenges of simultaneously obtaining electrophysiological data during ongoing stimulation. Furthermore, the mechanisms of action of tDCS in humans are not well understood. We have conducted a simultaneous tDCS-EEG study in a group of healthy human subjects. Significant acute and persistent changes in spontaneous neural activity and event related synchronization (ERS) were observed during and after the application of high definition tDCS over the left sensorimotor cortex. Both anodal and cathodal stimulation resulted in acute global changes in broadband cortical activity which were significantly different than the changes observed in response to sham stimulation. For the group of 8 subjects studied, broadband individual changes in spontaneous activity during stimulation were apparent both locally and globally. In addition, we found that high definition tDCS of the left sensorimotor cortex can induce significant ipsilateral and contralateral changes in event related desynchronization (ERD) and ERS during motor imagination following the end of the stimulation period. Overall, our results demonstrate the feasibility of acquiring high resolution EEG during high definition tDCS and provide evidence that tDCS in humans directly modulates rhythmic cortical synchronization during and after its administration. PMID:24956615

Momentum balance in four solar flares

NASA Technical Reports Server (NTRS)

Canfield, Richard C.; Metcalf, Thomas R.; Zarro, Dominic M.; Lemen, James R.

1990-01-01

Solar Maximum Mission soft X-ray spectra and National Solar Observatory (Sacramento Peak) H-alpha spectra were combined in a study of high-speed flows during the impulsive phase of four solar flares. In all events, a blue asymmetry (indicative of upflows) was observed in the coronal Ca XIX line during the soft X-ray rise phase. In all events a red asymmetry (indicative of downflows) was observed simultaneously in chromospheric H-alpha. These oppositely directed flows were concurrent with impulsive hard X-ray emission. Combining the velocity data with estimates of the density based on emission measurements and volume estimates, it is shown that for the impulsive phase as a whole the total momentum of upflowing soft X-ray plasma equaled that of the downflowing H-alpha plasma, to within an order of magnitude, in all four events. Only the chromospheric evaporation model predicts equal total momentum in the upflowing soft X-ray-emitting and downflowing H-alphba-emitting materials.

The Stereo Electron Spikes and the Interplanetary Magnetic Field

NASA Astrophysics Data System (ADS)

Jokipii, J. R.; Sheeley, N. R., Jr.; Wang, Y. M.; Giacalone, J.

2016-12-01

A recent paper (Klassen etal, 2015) discussed observations of a spike event of 55-65 keV electrons which occurred very nearly simultaneously at STEREO A and STEREO B, which at the time were separated in longitude by 38 degrees. The authors associated the spikes with a flare at the Sun near the footpoint of the nominal Archimedean spiral magnetic field line passing through STEREO A. The spike at STEREO A was delayed by 2.2 minutes from that at STEREOB. We discuss the observations in terms of a model in which the electrons, accelerated at the flare, propagate without significant scattering along magnetic field lines which separate or diverge as a function of radial distance from the Sun. The near simultaneity of the spikes at the two spacecraft is a natural consequence of this model. We interpret the divergence of the magnetic field lines as a consequence of field-line random walk and flux-tube expansion. We show that the field-line random walk in the absence of flux-tube expansion produces an rms spread of field lines significantly less than that which is required to produce to observed divergence. We find that observations of the solar wind and its source region at the time of the event can account for the observations in terms of propagation along interplanetary magnetic field-lines. Klassen, A., Dresing, N., Gomez-Herrero, R, and Heber, B., A&A 580, A115 (2015) Financial support for NS and YMW was provided by NASA and CNR.

Magnetic Field Dipolarization and Its Associated Ion Flux Variations in the Inner Magnetosphere: Simultaneous Observations by Arase and Michibiki Satellites

NASA Astrophysics Data System (ADS)

Nose, M.; Matsuoka, A.; Kasahara, S.; Yokota, S.; Higashio, N.; Koshiishi, H.; Imajo, S.; Teramoto, M.; Nomura, R.; Fujimoto, A.; Keika, K.; Tanaka, Y.; Shinohara, M.; Shinohara, I.; Yoshizumi, M.

2017-12-01

Recent satellite observations by MDS-1 and Van Allen Probes statistically revealed that magnetic field dipolarization can be detected over a wide range of L in the deep inner magnetosphere (i.e., L = 3.5-6.5, which is far inside the geosynchronous altitude). It is accompanied by magnetic field fluctuations having a characteristic timescale of a few to 10 s, which is comparable to the local gyroperiod of O+ ions. These magnetic field fluctuations are considered to cause nonadiabatic local acceleration of ions. In this study, we intend to confirm the above-mentioned characteristics of magnetic field dipolarization in the inner magnetosphere, using the magnetic field data and the energetic ion flux data measured by the Exploration of energization and Radiation in Geospace (ERG) "Arase" satellite. The Arase satellite was launched on December 20, 2016 into an elliptical orbit having an apogee of 6.0 Re, a perigee of 440 km altitude, an orbital period of 9.5 h, and an orbital inclination of 32 degrees. During the first magnetic storm of March 27, 2017 after Arase started scientific operation, Arase observes clear dipolarization signatures around 1500 UT at L 4.6 and MLT 5.7 hr. Strong magnetic field fluctuations are embedded in the magnetic field dipolarization and their characteristic frequency is close to the local gyrofrequency of O+ ions. Both H+ and O+ flux enhancements are observed in accordance with the dipolarization. These results are consistent with the previous results. In this event, the Quasi-Zenith Satellite (QZS)-1 "Michibiki" satellite was located at L 7.0 and MLT 23.8 hr, and observes similar dipolarization signatures with a few minute time difference. Simultaneous observations by both Arase and Michibiki provides us a unique opportunity to investigate how fast and wide the dipolarization propagates in the inner magnetosphere. In the presentation, we will show detailed analysis results of the dipolarization event on March 27, 2017 as well as similar events.

Modelling the occurrence of heat waves in maximum and minimum temperatures over Spain and projections for the period 2031-60

NASA Astrophysics Data System (ADS)

Abaurrea, J.; Asín, J.; Cebrián, A. C.

2018-02-01

The occurrence of extreme heat events in maximum and minimum daily temperatures is modelled using a non-homogeneous common Poisson shock process. It is applied to five Spanish locations, representative of the most common climates over the Iberian Peninsula. The model is based on an excess over threshold approach and distinguishes three types of extreme events: only in maximum temperature, only in minimum temperature and in both of them (simultaneous events). It takes into account the dependence between the occurrence of extreme events in both temperatures and its parameters are expressed as functions of time and temperature related covariates. The fitted models allow us to characterize the occurrence of extreme heat events and to compare their evolution in the different climates during the observed period. This model is also a useful tool for obtaining local projections of the occurrence rate of extreme heat events under climate change conditions, using the future downscaled temperature trajectories generated by Earth System Models. The projections for 2031-60 under scenarios RCP4.5, RCP6.0 and RCP8.5 are obtained and analysed using the trajectories from four earth system models which have successfully passed a preliminary control analysis. Different graphical tools and summary measures of the projected daily intensities are used to quantify the climate change on a local scale. A high increase in the occurrence of extreme heat events, mainly in July and August, is projected in all the locations, all types of event and in the three scenarios, although in 2051-60 the increase is higher under RCP8.5. However, relevant differences are found between the evolution in the different climates and the types of event, with a specially high increase in the simultaneous ones.

Simultaneous versus Sequential Bilateral Cataract Surgery for Infants with Congenital Cataracts: Visual Outcomes and Economic Costs

PubMed Central

Dave, Hreem; Phoenix, Vidya; Becker, Edmund R.; Lambert, Scott R.

2015-01-01

OBJECTIVES To compare the incidence of adverse events, visual outcomes and economic costs of sequential versus simultaneous bilateral cataract surgery for infants with congenital cataracts. METHODS We retrospectively reviewed the incidence of adverse events, visual outcomes and medical payments associated with simultaneous versus sequential bilateral cataract surgery for infants with congenital cataracts who underwent cataract surgery when 6 months of age or younger at our institution. RESULTS Records were available for 10 children who underwent sequential surgery at a mean age of 49 days for the first eye and 17 children who underwent simultaneous surgery at a mean age of 68 days (p=.25). We found a similar incidence of adverse events between the two treatment groups. Intraoperative or postoperative complications occurred in 14 eyes. The most common postoperative complication was glaucoma. No eyes developed endophthalmitis. The mean absolute interocular difference in logMAR visual acuities between the two treatment groups was 0.47±0.76 for the sequential group and 0.44±0.40 for the simultaneous group (p=.92). Hospital, drugs, supplies and professional payments were on average 21.9% lower per patient in the simultaneous group. CONCLUSIONS Simultaneous bilateral cataract surgery for infants with congenital cataracts was associated with a 21.9% reduction in medical payments and no discernible difference in the incidence of adverse events or visual outcome. PMID:20697007

Joint impact of North and South Pacific extratropical atmospheric variability on the onset of ENSO events

NASA Astrophysics Data System (ADS)

Ding, Ruiqiang; Li, Jianping; Tseng, Yu-heng; Sun, Cheng; Xie, Fei

2017-01-01

Previous studies have indicated that boreal winter subtropical and extratropical sea surface pressure (SLP) anomalies over both the North and South Pacific are significantly related to the El Niño-Southern Oscillation (ENSO) state in the following boreal winter. Here we use observational data and model simulations to show that the ability of the boreal winter North Pacific SLP anomalies to initiate ENSO events a year later may strongly depend on the state of the simultaneous South Pacific SLP anomalies and vice versa. When the boreal winter North Pacific SLP anomalies are of the opposite sign to the simultaneous South Pacific anomalies, the correlation of the North or South Pacific anomalies with the following ENSO state becomes much weaker, and the strength of the ENSO events also tends to be weaker. One possible reason for this is that when the boreal winter North and South Pacific SLP anomalies have the opposite sign, the westerly anomalies over the western-central equatorial Pacific during the following boreal summer are greatly reduced by the interference between the antecedent North and South Pacific SLP anomalies, thereby not favoring the development of ENSO events. Further analysis indicates that a combination of North and South Pacific precursor signals may serve to enhance the ENSO prediction skill.

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; Lynch, Kristina A.; Fernandes, Philip A.; Aruliah, Anasuya L.; Engebretson, Mark J.; Moen, Jøran I.; Oksavik, Kjellmar; Yahnin, Alexander G.; Yeoman, Timothy K.

2017-05-01

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements with corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.

New particle formation events arising from painting materials in an indoor microenvironment

NASA Astrophysics Data System (ADS)

Lazaridis, Mihalis; Serfozo, Norbert; Chatoutsidou, Sofia Eirini; Glytsos, Thodoros

2015-02-01

Particulate matter (PM) number size distribution and mass concentration along with total volatile organic compounds (TVOC) were measured during emissions from painting materials inside an indoor microenvironment. The emission sources were derived from oil painting medium and turpentine used for painting. Two sets of measurements (10 experiments) were conducted in a laboratory room of 54 m3. New particle formation events were observed in all 10 experiments. The nucleation events lasted on average less than one hour with an average growth rate 33.9 ± 9.1 nm/h and average formation rate 21.1 ± 8.7 cm-3s-1. After the end of the nucleation event, a condensational growth of indoor particles followed with average growth rate 11.6 ± 2.8 nm/h and duration between 1.4 and 4.1 h. High concentrations up to 3.24 ppm were measured for the indoor TVOC concentrations during the experiments. Simultaneous mass and number size concentration measurements were performed outdoors where no new particle formation event was observed. It is the first time that high nucleation rates indoors were observed in conjunction with high TVOC concentrations originating from painting materials which resulted to high exposure concentration levels of particle number concentration.

Widespread, Very Heavy Precipitation Events in Contemporary and Scenario Summer Climates from NARCCAP Simulations

NASA Astrophysics Data System (ADS)

Kawazoe, S.; Gutowski, W. J., Jr.

2015-12-01

We analyze the ability of regional climate models (RCMs) to simulate very heavy daily precipitation and supporting processes for both contemporary and future-scenario simulations during summer (JJA). RCM output comes from North American Regional Climate Change Assessment Program (NARCCAP) simulations, which are all run at a spatial resolution of 50 km. Analysis focuses on the upper Mississippi basin for summer, between 1982-1998 for the contemporary climate, and 2052-2068 during the scenario climate. We also compare simulated precipitation and supporting processes with those obtained from observed precipitation and reanalysis atmospheric states. Precipitation observations are from the University of Washington (UW) and the Climate Prediction Center (CPC) gridded dataset. Utilizing two observational datasets helps determine if any uncertainties arise from differences in precipitation gridding schemes. Reanalysis fields come from the North American Regional Reanalysis. The NARCCAP models generally reproduce well the precipitation-vs.-intensity spectrum seen in observations, while producing overly strong precipitation at high intensity thresholds. In the future-scenario climate, there is a decrease in frequency for light to moderate precipitation intensities, while an increase in frequency is seen for the higher intensity events. Further analysis focuses on precipitation events exceeding the 99.5 percentile that occur simultaneously at several points in the region, yielding so-called "widespread events". For widespread events, we analyze local and large scale environmental parameters, such as 2-m temperature and specific humidity, 500-hPa geopotential heights, Convective Available Potential Energy (CAPE), vertically integrated moisture flux convergence, among others, to compare atmospheric states and processes leading to such events in the models and observations. The results suggest that an analysis of atmospheric states supporting very heavy precipitation events is a more fruitful path for understanding and detecting changes than simply looking at precipitation itself.

Relationships of multitasking, physicians' strain, and performance: an observational study in ward physicians.

PubMed

Weigl, Matthias; Müller, Andreas; Sevdalis, Nick; Angerer, Peter

2013-03-01

Simultaneous task performance ("multitasking") is common in hospital physicians' work and is implicated as a major determinant for enhanced strain and detrimental performance. The aim was to determine the impact of multitasking by hospital physicians on their self reported strain and performance. A prospective observational time-and-motion study in a Community Hospital was conducted. Twenty-seven hospital physicians (surgical and internal specialties) were observed in 40 full-shift observations. Observed physicians reported twice on their self-monitored strain and performance during the observation time. Associations of observed multitasking events and subsequent strain and performance appraisals were calculated. About 21% of the working time physicians were engaged in simultaneous activities. The average time spent in multitasking activities correlated significantly with subsequently reported strain (r = 0.27, P = 0.018). The number of instances of multitasking activities correlated with self-monitored performance to a marginally significant level (r = 0.19, P = 0.098). Physicians who engage in multitasking activities tend to self-report better performance but at the cost of enhanced psychophysical strain. Hence, physicians do not perceive their own multitasking activities as a source for deficient performance, for example, medical errors. Readjustment of workload, improved organization of work for hospital physicians, and training programs to improve physicians' skills in dealing with multiple clinical demands, prioritization, and efficient task allocation may be useful avenues to explore to reduce the potentially negative impact of simultaneous task performance in clinical settings.

Weather observations on Whistler Mountain during five storms

NASA Astrophysics Data System (ADS)

Thériault, Julie M.; Rasmussen, Kristen L.; Fisico, Teresa; Stewart, Ronald E.; Joe, Paul; Gultepe, Ismail; Clément, Marilys; Isaac, George A.

2014-01-01

A greater understanding of precipitation formation processes over complex terrain near the west coast of British Colombia will contribute to many relevant applications, such as climate studies, local hydrology, transportation, and winter sport competition. The phase of precipitation is difficult to determine because of the warm and moist weather conditions experienced during the wintertime in coastal mountain ranges. The goal of this study is to investigate the wide range of meteorological conditions that generated precipitation on Whistler Mountain from 4-12 March 2010 during the SNOW-V10 field campaign. During this time period, five different storms were documented in detail and were associated with noticeably different meteorological conditions in the vicinity of Whistler Mountain. New measurement techniques, along with the SNOW-V10 instrumentation, were used to obtain in situ observations during precipitation events along the Whistler mountainside. The results demonstrate a high variability of weather conditions ranging from the synoptic-scale to the macro-scale. These weather events were associated with a variation of precipitation along the mountainside, such as events associated with snow, snow pellets, and rain. Only two events associated with a rain-snow transition along the mountainside were observed, even though above-freezing temperatures along the mountainside were recorded 90 % of the time. On a smaller scale, these events were also associated with a high variability of snowflake types that were observed simultaneously near the top of Whistler Mountain. Overall, these detailed observations demonstrate the importance of understanding small-scale processes to improve observational techniques, short-term weather prediction, and longer-term climate projections over mountainous regions.

Simultaneous vs sequential bilateral cataract surgery for infants with congenital cataracts: Visual outcomes, adverse events, and economic costs.

PubMed

Dave, Hreem; Phoenix, Vidya; Becker, Edmund R; Lambert, Scott R

2010-08-01

To compare the incidence of adverse events and visual outcomes and to compare the economic costs of sequential vs simultaneous bilateral cataract surgery for infants with congenital cataracts. Retrospective review of simultaneous vs sequential bilateral cataract surgery for infants with congenital cataracts who underwent cataract surgery when 6 months or younger at our institution. Records were available for 10 children who underwent sequential surgery at a mean age of 49 days for the first eye and 17 children who underwent simultaneous surgery at a mean age of 68 days (P = .25). We found a similar incidence of adverse events between the 2 treatment groups. Intraoperative or postoperative complications occurred in 14 eyes. The most common postoperative complication was glaucoma. No eyes developed endophthalmitis. The mean (SD) absolute interocular difference in logMAR visual acuities between the 2 treatment groups was 0.47 (0.76) for the sequential group and 0.44 (0.40) for the simultaneous group (P = .92). Payments for the hospital, drugs, supplies, and professional services were on average 21.9% lower per patient in the simultaneous group. Simultaneous bilateral cataract surgery for infants with congenital cataracts is associated with a 21.9% reduction in medical payments and no discernible difference in the incidence of adverse events or visual outcomes. However, our small sample size limits our ability to make meaningful comparisons of the relative risks and visual benefits of the 2 procedures.

Multi-Site Simultaneous Time-Resolved Photometry with a Low Cost Electro-Optics System †

PubMed Central

Gasdia, Forrest; Barjatya, Aroh; Bilardi, Sergei

2017-01-01

Sunlight reflected off of resident space objects can be used as an optical signal for astrometric orbit determination and for deducing geometric information about the object. With the increasing population of small satellites and debris in low Earth orbit, photometry is a powerful tool in operational support of space missions, whether for anomaly resolution or object identification. To accurately determine size, shape, spin rate, status of deployables, or attitude information of an unresolved resident space object, multi-hertz sample rate photometry is required to capture the relatively rapid changes in brightness that these objects can exhibit. OSCOM, which stands for Optical tracking and Spectral characterization of CubeSats for Operational Missions, is a low cost and portable telescope system capable of time-resolved small satellite photometry, and is field deployable on short notice for simultaneous observation from multiple sites. We present the electro-optical design principles behind OSCOM and light curves of the 1.5 U DICE-2 CubeSat and simultaneous observations of the main body of the ASTRO-H satellite after its fragmentation event. PMID:28556802

Multi-Site Simultaneous Time-Resolved Photometry with a Low Cost Electro-Optics System.

PubMed

Gasdia, Forrest; Barjatya, Aroh; Bilardi, Sergei

2017-05-30

Sunlight reflected off of resident space objects can be used as an optical signal for astrometric orbit determination and for deducing geometric information about the object. With the increasing population of small satellites and debris in low Earth orbit, photometry is a powerful tool in operational support of space missions, whether for anomaly resolution or object identification. To accurately determine size, shape, spin rate, status of deployables, or attitude information of an unresolved resident space object, multi-hertz sample rate photometry is required to capture the relatively rapid changes in brightness that these objects can exhibit. OSCOM, which stands for Optical tracking and Spectral characterization of CubeSats for Operational Missions, is a low cost and portable telescope system capable of time-resolved small satellite photometry, and is field deployable on short notice for simultaneous observation from multiple sites. We present the electro-optical design principles behind OSCOM and light curves of the 1.5 U DICE-2 CubeSat and simultaneous observations of the main body of the ASTRO-H satellite after its fragmentation event.

Common time-frequency analysis of local field potential and pyramidal cell activity in seizure-like events of the rat hippocampus

NASA Astrophysics Data System (ADS)

Cotic, M.; Chiu, A. W. L.; Jahromi, S. S.; Carlen, P. L.; Bardakjian, B. L.

2011-08-01

To study cell-field dynamics, physiologists simultaneously record local field potentials and the activity of individual cells from animals performing cognitive tasks, during various brain states or under pathological conditions. However, apart from spike shape and spike timing analyses, few studies have focused on elucidating the common time-frequency structure of local field activity relative to surrounding cells across different periods of phenomena. We have used two algorithms, multi-window time frequency analysis and wavelet phase coherence (WPC), to study common intracellular-extracellular (I-E) spectral features in spontaneous seizure-like events (SLEs) from rat hippocampal slices in a low magnesium epilepsy model. Both algorithms were applied to 'pairs' of simultaneously observed I-E signals from slices in the CA1 hippocampal region. Analyses were performed over a frequency range of 1-100 Hz. I-E spectral commonality varied in frequency and time. Higher commonality was observed from 1 to 15 Hz, and lower commonality was observed in the 15-100 Hz frequency range. WPC was lower in the non-SLE region compared to SLE activity; however, there was no statistical difference in the 30-45 Hz band between SLE and non-SLE modes. This work provides evidence of strong commonality in various frequency bands of I-E SLEs in the rat hippocampus, not only during SLEs but also immediately before and after.

How to Obtain the Lorentz Space Contraction Formula for a Moving Rod from Knowledge of the Positions of its Ends at Different Times

ERIC Educational Resources Information Center

Guasti, M. Fernandez; Zagoya, C.

2009-01-01

The Lorentz length contraction for a rod in uniform motion is derived performing two measurements at arbitrary times. Provided that the velocity of the rod is known, this derivation does not require the simultaneous measurement of two events. It thus avoids uncomfortable superluminal relationships. Furthermore, since the observer's simultaneous…

Insights from event-related potentials into the temporal and hierarchical organization of the ventral and dorsal streams of the visual system in selective attention.

PubMed

Martín-Loeches, M; Hinojosa, J A; Rubia, F J

1999-11-01

The temporal and hierarchical relationships between the dorsal and the ventral streams in selective attention are known only in relation to the use of spatial location as the attentional cue mediated by the dorsal stream. To improve this state of affairs, event-related brain potentials were recorded while subjects attended simultaneously to motion direction (mediated by the dorsal stream) and to a property mediated by the ventral stream (color or shape). At about the same time, a selection positivity (SP) started for attention mediated by both streams. However, the SP for color and shape peaked about 60 ms later than motion SP. Subsequently, a selection negativity (SN) followed by a late positive component (LPC) were found simultaneously for attention mediated by both streams. A hierarchical relationship between the two streams was not observed, but neither SN nor LPC for one property was completely insensitive to the values of the other property.

NASA SOFIA International Year of Light (IYL) Event: Infrared Light: Hanging out in the Stratosphere

NASA Astrophysics Data System (ADS)

Clark, Coral; Backman, Dana E.; Harman, Pamela; Veronico, Nicholas

2015-01-01

As an International Year of Light committee endorsed event, Infrared Light: Hanging out in the Stratosphere will engage learners around the world, linking participants with scientists at work on board NASA SOFIA, the world's largest flying observatory. This major event will showcase science-in-action, interviews, live data, and observations performed both aboard the aircraft and at partner centers on land.SOFIA (Stratospheric Observatory For Infrared Astronomy) is an 80% - 20% partnership of NASA and the German Aerospace Center (DLR) consisting of an extensively modified Boeing 747SP aircraft carrying a reflecting telescope with an effective diameter of 2.5 meters. SOFIA is a program in NASA's Science Mission Directorate, Astrophysics Division. Science investigators leverage SOFIA's unique capabilities to study the universe at infrared wavelengths by making observations that are impossible for even the largest and highest ground-based telescopes. SOFIA received Full Operating Capacity status in May, 2014, and astrophysicists will continue to utilize the observatory and upgraded instruments to study astronomical objects and phenomena, including star birth and death; planetary system formation; identification of complex molecules in space; planets, comets, and asteroids in our solar system; and nebulae and dust in galaxies.This landmark event will reflect and build on the ProjectLink. In October 1995, SOFIA's predecessor, the Kuiper Airborne Observatory (KAO), performed the first satellite links from an airplane to the ground. The KAO downlinked to the Exploratorium museum (SF, CA), where over 200 students watched the webcast, conversed, and participated in simultaneous observations at the world-renowned science museum. SOFIA will now take this concept into the 21st century, utilizing internet technologies to engage and inspire 100,000+ learners of all ages through simultaneous presentations and appearances by over 70 SOFIA Educators at schools and informal learning institutions across the U.S. and around the world, and build bridges for future authentic opportunities with high impact in STEM education.

Simultaneous lidar observations of the water vapor and ozone signatures of a stratospheric intrusion during the MOHAVE-2009 campaign

NASA Astrophysics Data System (ADS)

Leblanc, T.; McDermid, I. S.; Pérot, K.

2010-12-01

Ozone and water vapor signatures of a stratospheric intrusion were simultaneously observed by the Jet Propulsion Laboratory lidars located at Table Mountain Facility, California (TMF, 34.4N, 117.7W) during the Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE-2009) campaign in October 2009. These observations are placed in the context of the meridional displacement and folding of the tropopause, and resulting contrast in the properties of the air masses sampled by lidar. The lidar observations are supported by model data, specifically potential vorticity fields advected by the high-resolution transport model MIMOSA, and by 10-day backward isentropic trajectories. The ozone and water vapor anomalies measured by lidar were largely anti-correlated, and consistent with the assumption of a wet and ozone-poor subtropical upper troposphere, and a dry and ozone-rich extra-tropical lowermost stratosphere. However, it is shown that this anti-correlation relation collapsed just after the stratospheric intrusion event of October 20, suggesting mixed air embedded along the subtropical jet stream and sampled by lidar during its displacement south of TMF (tropopause fold). The ozone-PV expected positive correlation relation held strongly throughout the measurement period, including when a lower polar stratospheric filament passed over TMF just after the stratospheric intrusion. The numerous highly-correlated signatures observed during this event demonstrate the strong capability of the water vapor and ozone lidars at TMF, and provide new confidence in the future detection by lidar of long-term variability of water vapor and ozone in the Upper Troposphere-Lower Stratosphere (UTLS).

Making The Most Of Flaring M Dwarfs

NASA Astrophysics Data System (ADS)

Hunt-Walker, Nicholas; Hilton, E.; Kowalski, A.; Hawley, S.; Matthews, J.; Holtzman, J.

2011-01-01

We present observations of flare activity using the Microvariability and Oscillations of Stars (MOST) satellite in conjunction with simultaneous spectroscopic and photometric observations from the ARC 3.5-meter, NMSU 1.0-meter, and ARCSAT 0.5-meter telescopes at the Apache Point Observatory. The MOST observations enable unprecedented completeness with regard to observing frequent, low-energy flares on the well-known dMe flare star AD Leo with broadband photometry. The observations span approximately one week with a 60-second cadence and are sensitive to flares as small as 0.01-magnitudes. The time-resolved, ground-based spectroscopy gives measurements of Hα and other important chromospheric emission lines, whereas the Johnson U-, SDSS u-, and SDSS g-band photometry provide color information during the flare events and allow us to relate the MOST observations to decades of previous broadband observations. Understanding the rates and energetics of flare events on M dwarfs will help characterize this source of variability in large time-domain surveys such as LSST and Pan-STARRS. Flare rates are also of interest to astrobiology, since flares affect the habitability of exoplanets orbiting M dwarfs.

Quantifying full phenological event distributions reveals simultaneous advances, temporal stability and delays in spring and autumn migration timing in long-distance migratory birds.

PubMed

Miles, Will T S; Bolton, Mark; Davis, Peter; Dennis, Roy; Broad, Roger; Robertson, Iain; Riddiford, Nick J; Harvey, Paul V; Riddington, Roger; Shaw, Deryk N; Parnaby, David; Reid, Jane M

2017-04-01

Phenological changes in key seasonally expressed life-history traits occurring across periods of climatic and environmental change can cause temporal mismatches between interacting species, and thereby impact population and community dynamics. However, studies quantifying long-term phenological changes have commonly only measured variation occurring in spring, measured as the first or mean dates on which focal traits or events were observed. Few studies have considered seasonally paired events spanning spring and autumn or tested the key assumption that single convenient metrics accurately capture entire event distributions. We used 60 years (1955-2014) of daily bird migration census data from Fair Isle, Scotland, to comprehensively quantify the degree to which the full distributions of spring and autumn migration timing of 13 species of long-distance migratory bird changed across a period of substantial climatic and environmental change. In most species, mean spring and autumn migration dates changed little. However, the early migration phase (≤10th percentile date) commonly got earlier, while the late migration phase (≥90th percentile date) commonly got later. Consequently, species' total migration durations typically lengthened across years. Spring and autumn migration phenologies were not consistently correlated within or between years within species and hence were not tightly coupled. Furthermore, different metrics quantifying different aspects of migration phenology within seasons were not strongly cross-correlated, meaning that no single metric adequately described the full pattern of phenological change. These analyses therefore reveal complex patterns of simultaneous advancement, temporal stability and delay in spring and autumn migration phenologies, altering species' life-history structures. Additionally, they demonstrate that this complexity is only revealed if multiple metrics encompassing entire seasonal event distributions, rather than single metrics, are used to quantify phenological change. Existing evidence of long-term phenological changes detected using only one or two metrics should consequently be interpreted cautiously because divergent changes occurring simultaneously could potentially have remained undetected. © 2016 John Wiley & Sons Ltd.

Electron acceleration in solar flares

NASA Technical Reports Server (NTRS)

Droge, Wolfgang; Meyer, Peter; Evenson, Paul; Moses, Dan

1989-01-01

For the period Spetember 1978 to December 1982, 55 solar flare particle events for which the instruments on board the ISEE-3 spacecraft detected electrons above 10 MeV. Combining data with those from the ULEWAT spectrometer electron spectra in the range from 0.1 to 100 MeV were obtained. The observed spectral shapes can be divided into two classes. The spectra of the one class can be fit by a single power law in rigidity over the entire observed range. The spectra of the other class deviate from a power law, instead exhibiting a steepening at low rigidities and a flattening at high rigidities. Events with power-law spectra are associated with impulsive (less than 1 hr duration) soft X-ray emission, whereas events with hardening spectra are associated with long-duration (more than 1 hr) soft X-ray emission. The characteristics of long-duration events are consistent with diffusive shock acceleration taking place high in the corona. Electron spectra of short-duration flares are well reproduced by the distribution functions derived from a model assuming simultaneous second-order Fermi acceleration and Coulomb losses operating in closed flare loops.

Response of equatorial and low latitude mesosphere lower thermospheric dynamics to the northern hemispheric sudden stratospheric warming events

NASA Astrophysics Data System (ADS)

Koushik, N.; Kumar, Karanam Kishore; Ramkumar, Geetha; Subrahmanyam, K. V.

2018-04-01

The changes in zonal mean circulation and meridional temperature gradient brought about by Sudden Stratospheric Warming (SSW) events in polar middle atmosphere are found to significantly affect the low latitude counterparts. Several studies have revealed the signatures of SSW events in the low latitude Mesosphere- Lower Thermosphere (MLT) region. Using meteor wind radar observations, the present study investigates the response of semidiurnal oscillations and quasi 2-day waves in the MLT region, simultaneously over low latitude and equatorial stations Thumba (8.5oN, 76.5oE) and Kototabang (0.2oS, 100oE). Unlike many case studies, the present analysis examines the response of low and equatorial latitude MLT region to typical polar stratospheric conditions viz., Quiet winter, Major SSW winter and Minor SSW winter. The present results show that (i) the amplitudes of semidiurnal oscillations and quasi 2-day waves in the equatorial and low latitude MLT region enhance in association with major SSW events, (ii) the semidiurnal oscillations show significant enhancement selectively in the zonal and meridional components over the Northern Hemispheric low latitude and the equatorial stations, respectively (iii) The minor SSW event of January 2012 resulted in anomalously large amplitudes of quasi 2- day waves without any notable increase in the amplitude of semidiurnal oscillations. The significance of the present study lies in comprehensively bringing out the signatures of SSW events in the semidiurnal oscillations and quasi 2-day waves in low latitude and equatorial MLT region, simultaneously for the first time over these latitudes.

Simultaneous event-specific estimates of transport, loss, and source rates for relativistic outer radiation belt electrons: Event-Specific 1-D Modeling

DOE PAGES

Schiller, Q.; Tu, W.; Ali, A. F.; ...

2017-03-11

The most significant unknown regarding relativistic electrons in Earth’s outer Van Allen radiation belt is the relative contribution of loss, transport, and acceleration processes within the inner magnetosphere. Detangling each individual process is critical to improve the understanding of radiation belt dynamics, but determining a single component is challenging due to sparse measurements in diverse spatial and temporal regimes. However, there are currently an unprecedented number of spacecraft taking measurements that sample different regions of the inner magnetosphere. With the increasing number of varied observational platforms, system dynamics can begin to be unraveled. In this work, we employ in-situ measurementsmore » during the 13-14 January 2013 enhancement event to isolate transport, loss, and source dynamics in a one dimensional radial diffusion model. We then validate the results by comparing them to Van Allen Probes and THEMIS observations, indicating that the three terms have been accurately and individually quantified for the event. Finally, a direct comparison is performed between the model containing event-specific terms and various models containing terms parameterized by geomagnetic index. Models using a simple 3/Kp loss timescale show deviation from the event specific model of nearly two orders of magnitude within 72 hours of the enhancement event. However, models using alternative loss timescales closely resemble the event specific model.« less

Simultaneous event-specific estimates of transport, loss, and source rates for relativistic outer radiation belt electrons: Event-Specific 1-D Modeling

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

Schiller, Q.; Tu, W.; Ali, A. F.

The most significant unknown regarding relativistic electrons in Earth’s outer Van Allen radiation belt is the relative contribution of loss, transport, and acceleration processes within the inner magnetosphere. Detangling each individual process is critical to improve the understanding of radiation belt dynamics, but determining a single component is challenging due to sparse measurements in diverse spatial and temporal regimes. However, there are currently an unprecedented number of spacecraft taking measurements that sample different regions of the inner magnetosphere. With the increasing number of varied observational platforms, system dynamics can begin to be unraveled. In this work, we employ in-situ measurementsmore » during the 13-14 January 2013 enhancement event to isolate transport, loss, and source dynamics in a one dimensional radial diffusion model. We then validate the results by comparing them to Van Allen Probes and THEMIS observations, indicating that the three terms have been accurately and individually quantified for the event. Finally, a direct comparison is performed between the model containing event-specific terms and various models containing terms parameterized by geomagnetic index. Models using a simple 3/Kp loss timescale show deviation from the event specific model of nearly two orders of magnitude within 72 hours of the enhancement event. However, models using alternative loss timescales closely resemble the event specific model.« less

Simultaneous Retrieval of Temperature, Water Vapor and Ozone Atmospheric Profiles from IASI: Compression, De-noising, First Guess Retrieval and Inversion Algorithms

NASA Technical Reports Server (NTRS)

Aires, F.; Rossow, W. B.; Scott, N. A.; Chedin, A.; Hansen, James E. (Technical Monitor)

2001-01-01

A fast temperature water vapor and ozone atmospheric profile retrieval algorithm is developed for the high spectral resolution Infrared Atmospheric Sounding Interferometer (IASI) space-borne instrument. Compression and de-noising of IASI observations are performed using Principal Component Analysis. This preprocessing methodology also allows, for a fast pattern recognition in a climatological data set to obtain a first guess. Then, a neural network using first guess information is developed to retrieve simultaneously temperature, water vapor and ozone atmospheric profiles. The performance of the resulting fast and accurate inverse model is evaluated with a large diversified data set of radiosondes atmospheres including rare events.

Optimization of high count rate event counting detector with Microchannel Plates and quad Timepix readout

NASA Astrophysics Data System (ADS)

Tremsin, A. S.; Vallerga, J. V.; McPhate, J. B.; Siegmund, O. H. W.

2015-07-01

Many high resolution event counting devices process one event at a time and cannot register simultaneous events. In this article a frame-based readout event counting detector consisting of a pair of Microchannel Plates and a quad Timepix readout is described. More than 104 simultaneous events can be detected with a spatial resolution of 55 μm, while >103 simultaneous events can be detected with <10 μm spatial resolution when event centroiding is implemented. The fast readout electronics is capable of processing >1200 frames/sec, while the global count rate of the detector can exceed 5×108 particles/s when no timing information on every particle is required. For the first generation Timepix readout, the timing resolution is limited by the Timepix clock to 10-20 ns. Optimization of the MCP gain, rear field voltage and Timepix threshold levels are crucial for the device performance and that is the main subject of this article. These devices can be very attractive for applications where the photon/electron/ion/neutron counting with high spatial and temporal resolution is required, such as energy resolved neutron imaging, Time of Flight experiments in lidar applications, experiments on photoelectron spectroscopy and many others.

Simultaneous Determination of Structure and Event Location Using Body and Surface Wave Measurements at a Single Station: Preparation for Mars Data from the InSight Mission

NASA Astrophysics Data System (ADS)

Panning, M. P.; Banerdt, W. B.; Beucler, E.; Blanchette-Guertin, J. F.; Boese, M.; Clinton, J. F.; Drilleau, M.; James, S. R.; Kawamura, T.; Khan, A.; Lognonne, P. H.; Mocquet, A.; van Driel, M.

2015-12-01

An important challenge for the upcoming InSight mission to Mars, which will deliver a broadband seismic station to Mars along with other geophysical instruments in 2016, is to accurately determine event locations with the use of a single station. Locations are critical for the primary objective of the mission, determining the internal structure of Mars, as well as a secondary objective of measuring the activity of distribution of seismic events. As part of the mission planning process, a variety of techniques have been explored for location of marsquakes and inversion of structure, and preliminary procedures and software are already under development as part of the InSight Mars Quake and Mars Structure Services. One proposed method, involving the use of recordings of multiple-orbit surface waves, has already been tested with synthetic data and Earth recordings. This method has the strength of not requiring an a priori velocity model of Mars for quake location, but will only be practical for larger events. For smaller events where only first orbit surface waves and body waves are observable, other methods are required. In this study, we implement a transdimensional Bayesian inversion approach to simultaneously invert for basic velocity structure and location parameters (epicentral distance and origin time) using only measurements of body wave arrival times and dispersion of first orbit surface waves. The method is tested with synthetic data with expected Mars noise and Earth data for single events and groups of events and evaluated for errors in both location and structural determination, as well as tradeoffs between resolvable parameters and the effect of 3D crustal variations.

Unusual Central Engine Activity in the Double Burst GRB 110709B

NASA Technical Reports Server (NTRS)

Zhang, Bin-Bin; Burrows, David N.; Zhang, Bing; Meszaros, Peter; Stratta, Giulia; D'Elia, Valerio; Frederiks, Dmitry; Golenetskii, S.; Cummings, Jay R.; Wang, Xiang-Yu;

Grouping and Segregation of Sensory Events by Actions in Temporal Audio-Visual Recalibration.

PubMed

Ikumi, Nara; Soto-Faraco, Salvador

2016-01-01

Perception in multi-sensory environments involves both grouping and segregation of events across sensory modalities. Temporal coincidence between events is considered a strong cue to resolve multisensory perception. However, differences in physical transmission and neural processing times amongst modalities complicate this picture. This is illustrated by cross-modal recalibration, whereby adaptation to audio-visual asynchrony produces shifts in perceived simultaneity. Here, we examined whether voluntary actions might serve as a temporal anchor to cross-modal recalibration in time. Participants were tested on an audio-visual simultaneity judgment task after an adaptation phase where they had to synchronize voluntary actions with audio-visual pairs presented at a fixed asynchrony (vision leading or vision lagging). Our analysis focused on the magnitude of cross-modal recalibration to the adapted audio-visual asynchrony as a function of the nature of the actions during adaptation, putatively fostering cross-modal grouping or, segregation. We found larger temporal adjustments when actions promoted grouping than segregation of sensory events. However, a control experiment suggested that additional factors, such as attention to planning/execution of actions, could have an impact on recalibration effects. Contrary to the view that cross-modal temporal organization is mainly driven by external factors related to the stimulus or environment, our findings add supporting evidence for the idea that perceptual adjustments strongly depend on the observer's inner states induced by motor and cognitive demands.

Grouping and Segregation of Sensory Events by Actions in Temporal Audio-Visual Recalibration

PubMed Central

Ikumi, Nara; Soto-Faraco, Salvador

2017-01-01

Perception in multi-sensory environments involves both grouping and segregation of events across sensory modalities. Temporal coincidence between events is considered a strong cue to resolve multisensory perception. However, differences in physical transmission and neural processing times amongst modalities complicate this picture. This is illustrated by cross-modal recalibration, whereby adaptation to audio-visual asynchrony produces shifts in perceived simultaneity. Here, we examined whether voluntary actions might serve as a temporal anchor to cross-modal recalibration in time. Participants were tested on an audio-visual simultaneity judgment task after an adaptation phase where they had to synchronize voluntary actions with audio-visual pairs presented at a fixed asynchrony (vision leading or vision lagging). Our analysis focused on the magnitude of cross-modal recalibration to the adapted audio-visual asynchrony as a function of the nature of the actions during adaptation, putatively fostering cross-modal grouping or, segregation. We found larger temporal adjustments when actions promoted grouping than segregation of sensory events. However, a control experiment suggested that additional factors, such as attention to planning/execution of actions, could have an impact on recalibration effects. Contrary to the view that cross-modal temporal organization is mainly driven by external factors related to the stimulus or environment, our findings add supporting evidence for the idea that perceptual adjustments strongly depend on the observer's inner states induced by motor and cognitive demands. PMID:28154529

Conjugate LEP Events at Palmer Station, Antarctica: Hemisphere-Dependent Timing

NASA Astrophysics Data System (ADS)

Kim, D.; Moore, R. C.

2016-12-01

During March 2015, a large number of lightning-induced electron precipitation (LEP) events were simultaneously observed using very low frequency receivers in both the northern and southern hemispheres. After removing overlapping events and unclear (or not well-defined) events, 22 conjugate LEP events remain and are used to statistically analyze the hemispheric dependence of LEP onset time. LEP events were detected in the northern hemisphere using the VLF remote sensing method by tracking the NAA transmitter signal (24.0 kHz, Cutler, Maine) at Tuscaloosa, Alabama. In the southern hemisphere, the NPM transmitter signal (21.4 kHz, Laulaulei, Hawii) is tracked at Palmer station, Antarctica. In each case, the GLD360 dataset from Vaisala is used to determine the hemisphere of the causative lightning flash, and this is compared with the hemisphere in which the LEP event is detected first. The onset times and onset durations can be calculated using a number of different methods, however. In this paper, we compare and contrast the onset times and durations calculated using multiple different methods, with each method applied to the same 22 conjugate LEP events.

Single-shot optical recording with sub-picosecond resolution spans record nanosecond lengths

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

Muir, Ryan; Heebner, John

With the advent of electronics, oscilloscopes and photodiodes are now routinely capable of measuring events well below nanosecond resolution. However, these electronic instruments do not currently measure events below 10 ps resolution. From Walden’s observation that there is an engineering tradeoff between electronic bit depth and temporal resolution in analog-to-digital converters, this technique is projected to have extremely poor fidelity if it is extended to record single events with picosecond resolution. While this constraint may be circumvented with extensive signal averaging or other multiple measurements approaches, rare events and nonrepetitive events cannot be observed with this technique. Techniques capable ofmore » measuring information in a single shot are often required. There is a general lack of available technologies that are easily scalable to long records with sub-picosecond resolution, and are simultaneously versatile in wavelength of operation. Since it is difficult to scale electronic methods to shorter resolutions, we instead aim to scale optical methods to longer records. Demonstrated optical recording methods that have achieved 1 ps resolution and long recording lengths rely on either time scaling to slow down the temporal information or, like Wien, perform time-to-space mapping so that fast events may be captured with a conventional camera.« less

Single-shot optical recording with sub-picosecond resolution spans record nanosecond lengths

DOE PAGES

Muir, Ryan; Heebner, John

2018-01-18

With the advent of electronics, oscilloscopes and photodiodes are now routinely capable of measuring events well below nanosecond resolution. However, these electronic instruments do not currently measure events below 10 ps resolution. From Walden’s observation that there is an engineering tradeoff between electronic bit depth and temporal resolution in analog-to-digital converters, this technique is projected to have extremely poor fidelity if it is extended to record single events with picosecond resolution. While this constraint may be circumvented with extensive signal averaging or other multiple measurements approaches, rare events and nonrepetitive events cannot be observed with this technique. Techniques capable ofmore » measuring information in a single shot are often required. There is a general lack of available technologies that are easily scalable to long records with sub-picosecond resolution, and are simultaneously versatile in wavelength of operation. Since it is difficult to scale electronic methods to shorter resolutions, we instead aim to scale optical methods to longer records. Demonstrated optical recording methods that have achieved 1 ps resolution and long recording lengths rely on either time scaling to slow down the temporal information or, like Wien, perform time-to-space mapping so that fast events may be captured with a conventional camera.« less

Overview and early results of the Global Lightning and Sprite Measurements mission

NASA Astrophysics Data System (ADS)

Sato, M.; Ushio, T.; Morimoto, T.; Kikuchi, M.; Kikuchi, H.; Adachi, T.; Suzuki, M.; Yamazaki, A.; Takahashi, Y.; Inan, U.; Linscott, I.; Ishida, R.; Sakamoto, Y.; Yoshida, K.; Hobara, Y.; Sano, T.; Abe, T.; Nakamura, M.; Oda, H.; Kawasaki, Z.-I.

2015-05-01

Global Lightning and Sprite Measurements on Japanese Experiment Module (JEM-GLIMS) is a space mission to conduct the nadir observations of lightning discharges and transient luminous events (TLEs). The main objectives of this mission are to identify the horizontal distribution of TLEs and to solve the occurrence conditions determining the spatial distribution. JEM-GLIMS was successfully launched and started continuous nadir observations in 2012. The global distribution of the detected lightning events shows that most of the events occurred over continental regions in the local summer hemisphere. In some events, strong far-ultraviolet emissions have been simultaneously detected with N2 1P and 2P emissions by the spectrophotometers, which strongly suggest the occurrence of TLEs. Especially, in some of these events, no significant optical emission was measured by the narrowband filter camera, which suggests the occurrence of elves, not sprites. The VLF receiver also succeeded in detecting lightning whistlers, which show clear falling-tone frequency dispersion. Based on the optical data, the time delay from the detected lightning emission to the whistlers was identified as ˜10 ms, which can be reasonably explained by the wave propagation with the group velocity of whistlers. The VHF interferometer conducted the spaceborne interferometric observations and succeeded in detecting VHF pulses. We observed that the VHF pulses are likely to be excited by the lightning discharge possibly related with in-cloud discharges and measured with the JEM-GLIMS optical instruments. Thus, JEM-GLIMS provides the first full set of optical and electromagnetic data of lightning and TLEs obtained by nadir observations from space.

Retroactive Event Determination and Its Relativistic Roots

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

Nelson, Sky E.

Quantum theory limits what we are allowed to say about the 'true' state of a quantum system if that system is unobserved. But special relativity relies fundamentally on a universal assumption about what a light particle is doing at ALL times, regardless of being observed (namely, traveling at speed c relative to any inertial observer). This constitutes a fundamental conceptual gap between the theories. In resolving this impasse we show that the state of a light particle (and hence space and time) is not objective or continuous. Time dilation and length contraction become infinite for a photon, so light hasmore » no 'experience' of event separation in space or time ({Delta}t' = 0, {Delta}x' = 0). The principle of simultaneity is applied between an inertial observer and a light particle, such that the relative speed of the two systems is c, and gamma = infinite/undefined. Although light experiences no separation between events, the Lorentz transform {Delta}t' = {gamma} ({Delta}t-{Delta}Lv/c{sup 2}) implies that the inertial observer experiences a separation between those same events of exactly {Delta}t = {Delta}L/c, a light-like separation. In other words, although light does not 'register' time or space itself, light will always be measured by an inertial observer at a position and time exactly as if it had travelled at speed c continuously through the intervening medium. This fits nicely within the limitations set by quantum mechanics. This result is connected with previous work on retroactive event determination, suggesting the ubiquitous existence of ''synchronicity''.« less

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling: M-I-T COUPLING OF TCV

DOE PAGES

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.; ...

2017-03-11

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements withmore » corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.« less

Simultaneous observations of traveling convection vortices: Ionosphere-thermosphere coupling: M-I-T COUPLING OF TCV

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

Kim, Hyomin; Lessard, Marc R.; Jones, Sarah L.

We present simultaneous observations of magnetosphere-ionosphere-thermosphere coupling over Svalbard during a traveling convection vortex (TCV) event. Various spaceborne and ground-based instruments made coordinated measurements, including magnetometers, particle detectors, an all-sky camera, European Incoherent Scatter (EISCAT) Svalbard Radar, Super Dual Auroral Radar Network (SuperDARN), and SCANning Doppler Imager (SCANDI). The instruments recorded TCVs associated with a sudden change in solar wind dynamic pressure. The data display typical features of TCVs including vortical ionospheric convection patterns seen by the ground magnetometers and SuperDARN radars and auroral precipitation near the cusp observed by the all-sky camera. Simultaneously, electron and ion temperature enhancements withmore » corresponding density increase from soft precipitation are also observed by the EISCAT Svalbard Radar. The ground magnetometers also detected electromagnetic ion cyclotron waves at the approximate time of the TCV arrival. This implies that they were generated by a temperature anisotropy resulting from a compression on the dayside magnetosphere. SCANDI data show a divergence in thermospheric winds during the TCVs, presumably due to thermospheric heating associated with the current closure linked to a field-aligned current system generated by the TCVs. We conclude that solar wind pressure impulse-related transient phenomena can affect even the upper atmospheric dynamics via current systems established by a magnetosphere-ionosphere-thermosphere coupling process.« less

Simultaneous Forbush decreases and associated geomagnetic storms during the last three solar cycles

NASA Astrophysics Data System (ADS)

Okpala, K. C.

2013-12-01

Forbush decrease (FD) are observed reduction in galactic cosmic ray (GCR) intensity as measured by ground neutron monitors. FD is associated with increased activity of the sun as reflected in the size of the interplanetary coronal mass ejections passing around the Earth and the corotating regions in the Heliosphere. Since the interplanetary anisotropy evolves itself during a geomagnetic storm in addition to the reconfiguration of external magnetospheric currents, it is expected that changes in transmissivity of cosmic rays of glactic origin will occur during Geomagnetic storms. In this study we examine over one hundred and fifty (150) FD events and associated geomagnetic storms over the last three solar cycles from 1970 to 2003. The negative peaks of the FDs and the Dst coincided for most of the events (~70%). There was good correlation (>0.65) between the FDs and Dst. Fresh evidence of the influence of external magnetospheric currents on the count rates of the neutron monitors stations during periods of Forbush decreases (FDs) is provided. This evidence is observed as sudden increases in the count rates during the main phase of simultaneous FD. The magnitude of the sudden rise in the count rates of Neutron monitors and peak dst correlated well (>0.50) both for high latitude and mid latitude stations.

Application of rain scanner SANTANU and transportable weather radar in analyze of Mesoscale Convective System (MCS) events over Bandung, West Java

NASA Astrophysics Data System (ADS)

Nugroho, G. A.; Sinatra, T.; Trismidianto; Fathrio, I.

2018-05-01

Simultaneous observation of transportable weather radar LAPAN-GMR25SP and rain-scanner SANTANU were conducted in Bandung and vicinity. The objective is to observe and analyse the weather condition in this area during rainy and transition season from March until April 2017. From the observation result reported some heavy rainfall with hail and strong winds occurred on March 17th and April 19th 2017. This events were lasted within 1 to 2 hours damaged some properties and trees in Bandung. Mesoscale convective system (MCS) are assumed to be the cause of this heavy rainfall. From two radar data analysis showed a more local convective activity in around 11.00 until 13.00 LT. This local convective activity are showed from the SANTANU observation supported by the VSECT and CMAX of the Transportable radar data that signify the convective activity within those area. MCS activity were observed one hour after that. This event are confirm by the classification of convective-stratiform echoes from radar data and also from the high convective index from Tbb Himawari 8 satellite data. The different MCS activity from this two case study is that April 19 have much more MCS activity than in March 17, 2017.

Observations of Reconnection Flows in a Flare on the Solar Disk

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

Wang, Juntao; Simões, P. J. A.; Jeffrey, N. L. S.

Magnetic reconnection is a well-accepted part of the theory of solar eruptive events, though the evidence is still circumstantial. Intrinsic to the reconnection picture of a solar eruptive event, particularly in the standard model for two-ribbon flares (CSHKP model), are an advective flow of magnetized plasma into the reconnection region, expansion of field above the reconnection region as a flux rope erupts, retraction of heated post-reconnection loops, and downflows of cooling plasma along those loops. We report on a unique set of Solar Dynamics Observatory /Atmospheric Imaging Assembly imaging and Hinode /EUV Imaging Spectrometer spectroscopic observations of the disk flaremore » SOL2016-03-23T03:54 in which all four flows are present simultaneously. This includes spectroscopic evidence for a plasma upflow in association with large-scale expanding closed inflow field. The reconnection inflows are symmetric, and consistent with fast reconnection, and the post-reconnection loops show a clear cooling and deceleration as they retract. Observations of coronal reconnection flows are still rare, and most events are observed at the solar limb, obscured by complex foregrounds, making their relationship to the flare ribbons, cusp field, and arcades formed in the lower atmosphere difficult to interpret. The disk location and favorable perspective of this event have removed these ambiguities giving a clear picture of the reconnection dynamics.« less

Fγ: A new observable for photon-hadron discrimination in hybrid air shower events

NASA Astrophysics Data System (ADS)

Niechciol, M.; Risse, M.; Ruehl, P.; Settimo, M.; Younk, P. W.; Yushkov, A.

2018-01-01

To search for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. We present a new observable, Fγ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. Fγ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known Xmax observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), Fγ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable Fγ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Furthermore, Fγ complements nicely to Xmax such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.

A case study of aerosol scavenging in a biomass burning plume over eastern Canada during the 2011 BORTAS field experiment

NASA Astrophysics Data System (ADS)

Franklin, J. E.; Drummond, J. R.; Griffin, D.; Pierce, J. R.; Waugh, D. L.; Palmer, P. I.; Parrington, M.; Lee, J. D.; Lewis, A. C.; Rickard, A. R.; Taylor, J. W.; Allan, J. D.; Coe, H.; Walker, K. A.; Chisholm, L.; Duck, T. J.; Hopper, J. T.; Blanchard, Y.; Gibson, M. D.; Curry, K. R.; Sakamoto, K. M.; Lesins, G.; Dan, L.; Kliever, J.; Saha, A.

2014-08-01

We present measurements of a long-range smoke transport event recorded on 20-21 July 2011 over Halifax, Nova Scotia, Canada, during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS-B) campaign. Ground-based Fourier transform spectrometers and photometers detected air masses associated with large wildland fires burning in eastern Manitoba and western Ontario. We investigate a plume with high trace gas amounts but low amounts of particles that preceded and overlapped at the Halifax site with a second plume with high trace gas loadings and significant amounts of particulate material. We show that the first plume experienced a meteorological scavenging event, but the second plume had not been similarly scavenged. This points to the necessity to account carefully for the plume history when considering long-range transport since simultaneous or near-simultaneous times of arrival are not necessarily indicative of either similar trajectories or meteorological history. We investigate the origin of the scavenged plume, and the possibility of an aerosol wet deposition event occurring in the plume ~ 24 h prior to the measurements over Halifax. The region of lofting and scavenging is only monitored on an intermittent basis by the present observing network, and thus we must consider many different pieces of evidence in an effort to understand the early dynamics of the plume. Through this discussion we also demonstrate the value of having many simultaneous remote-sensing measurements in order to understand the physical and chemical behaviour of biomass burning plumes.

A case study of aerosol depletion in a biomass burning plume over Eastern Canada during the 2011 BORTAS field experiment

NASA Astrophysics Data System (ADS)

Franklin, J. E.; Drummond, J. R.; Griffin, D.; Pierce, J. R.; Waugh, D. L.; Palmer, P. I.; Parrington, M.; Lee, J. D.; Lewis, A. C.; Rickard, A. R.; Taylor, J. W.; Allan, J. D.; Coe, H.; Walker, K. A.; Chisholm, L.; Duck, T. J.; Hopper, J. T.; Blanchard, Y.; Gibson, M. D.; Curry, K. R.; Sakamoto, K. M.; Lesins, G.; Dan, L.; Kliever, J.; Saha, A.

2014-02-01

We present measurements of a long range smoke transport event recorded on 20-21 July 2011 over Halifax, Nova Scotia, Canada, during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS-B) campaign. Ground-based Fourier transform spectrometers and photometers detected air masses associated with large wildland fires burning in eastern Manitoba and western Ontario. We investigate a plume with high trace gas amounts but low amounts of particles that preceded and overlapped at the Halifax site with a second plume with high trace gas loadings and significant amounts of particulate material. We show that the first plume experienced a meteorological scavenging event but the second plume had not been similarly scavenged. This points to the necessity to account carefully for the plume history when considering long range transport since simultaneous or near-simultaneous times of arrival are not necessarily indicative of either similar trajectories or meteorological history. We investigate the origin of the scavenged plume, and the possibility of an aerosol wet deposition event occurring in the plume ~24 h prior to the measurements over Halifax. The region of lofting and scavenging is only monitored on an intermittent basis by the present observing network, and thus we must consider many different pieces of evidence in an effort to understand the early dynamics of the plume. Through this discussion we also demonstrate the value of having many simultaneous remote-sensing measurements in order to understand the physical and chemical behaviour of biomass burning plumes.

Assessing distractors and teamwork during surgery: developing an event-based method for direct observation.

PubMed

Seelandt, Julia C; Tschan, Franziska; Keller, Sandra; Beldi, Guido; Jenni, Nadja; Kurmann, Anita; Candinas, Daniel; Semmer, Norbert K

2014-11-01

To develop a behavioural observation method to simultaneously assess distractors and communication/teamwork during surgical procedures through direct, on-site observations; to establish the reliability of the method for long (>3 h) procedures. Observational categories for an event-based coding system were developed based on expert interviews, observations and a literature review. Using Cohen's κ and the intraclass correlation coefficient, interobserver agreement was assessed for 29 procedures. Agreement was calculated for the entire surgery, and for the 1st hour. In addition, interobserver agreement was assessed between two tired observers and between a tired and a non-tired observer after 3 h of surgery. The observational system has five codes for distractors (door openings, noise distractors, technical distractors, side conversations and interruptions), eight codes for communication/teamwork (case-relevant communication, teaching, leadership, problem solving, case-irrelevant communication, laughter, tension and communication with external visitors) and five contextual codes (incision, last stitch, personnel changes in the sterile team, location changes around the table and incidents). Based on 5-min intervals, Cohen's κ was good to excellent for distractors (0.74-0.98) and for communication/teamwork (0.70-1). Based on frequency counts, intraclass correlation coefficient was excellent for distractors (0.86-0.99) and good to excellent for communication/teamwork (0.45-0.99). After 3 h of surgery, Cohen's κ was 0.78-0.93 for distractors, and 0.79-1 for communication/teamwork. The observational method developed allows a single observer to simultaneously assess distractors and communication/teamwork. Even for long procedures, high interobserver agreement can be achieved. Data collected with this method allow for investigating separate or combined effects of distractions and communication/teamwork on surgical performance and patient outcomes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Search for WZ + ZZ productions with missing transverse energy + jets with b enhancement at \\(\\sqrt{s} = 1.96\\) TeV

DOE PAGES

Aaltonen, T.; Gonzalez, B. Alvarez; Amerio, S.; ...

2012-01-06

Diboson production (WW + WZ + ZZ) has been observed at the Tevatron in hadronic decay modes dominated by the WW process. This paper describes the measurement of the cross section of WZ and ZZ events in final states with large E T and using b-jet identification as a tool to suppress WW contributions. Due to the limited energy resolution, we cannot distinguish between partially hadronic decays of WZ and ZZ, and we measure the sum of these processes. The number of signal events is extracted using a simultaneous fit to the invariant mass distribution of the two jets formore » events with two b-jet candidates and events without two b-jet candidates. We measure a cross section Σ(pp¯ → WZ,ZZ) = 5.8 -3.0 +3.6 pb, in agreement with the standard model.« less

Applied Use of Safety Event Occurrence Control Charts of Harm and Non-Harm Events: A Case Study.

PubMed

Robinson, Susan N; Neyens, David M; Diller, Thomas

Most hospitals use occurrence reporting systems that facilitate identifying serious events that lead to root cause investigations. Thus, the events catalyze improvement efforts to mitigate patient harm. A serious limitation is that only a few of the occurrences are investigated. A challenge is leveraging the data to generate knowledge. The goal is to present a methodology to supplement these incident assessment efforts. The framework affords an enhanced understanding of patient safety through the use of control charts to monitor non-harm and harm incidents simultaneously. This approach can identify harm and non-harm reporting rates and also can facilitate monitoring occurrence trends. This method also can expedite identifying changes in workflow, processes, or safety culture. Although unable to identify root causes, this approach can identify changes in near real time. This approach also supports evaluating safety or policy interventions that may not be observable in annual safety climate surveys.

On the acquisition of temporal conjunctions in Finnish.

PubMed

Atanassova, M

2001-03-01

This study concerns the acquisition of complex sentence structures in Finnish. Specifically, three simultaneous and sequential events were acted out with toys in an elicitation task, and the production of "and," "and then," "when," and "after" were observed. There were 48 children in a cross-sectional design at the age levels 3, 4, 5, and 6 years. Immediately after the complex event was presented, the child was asked the initial request "What happened?" If the child did not produce the whole event spontaneously, she or he was prompted by "What else happened?" Finally, the prompted request "When did X?" was asked (X referring to the second action component of the event). The results showed that prompting better revealed the ability of the children, especially that of the younger ones, to use temporal conjunctions in complex sentences, as well as the delicate interplay of language skills and their flexible use.

The psychophysiology of real-time financial risk processing.

PubMed

Lo, Andrew W; Repin, Dmitry V

2002-04-01

A longstanding controversy in economics and finance is whether financial markets are governed by rational forces or by emotional responses. We study the importance of emotion in the decision-making process of professional securities traders by measuring their physiological characteristics (e.g., skin conductance, blood volume pulse, etc.) during live trading sessions while simultaneously capturing real-time prices from which market events can be detected. In a sample of 10 traders, we find statistically significant differences in mean electrodermal responses during transient market events relative to no-event control periods, and statistically significant mean changes in cardiovascular variables during periods of heightened market volatility relative to normal-volatility control periods. We also observe significant differences in these physiological responses across the 10 traders that may be systematically related to the traders' levels of experience.

Observations of transient events with Mini-MegaTORTORA wide-field monitoring system with sub-second temporal resolution

NASA Astrophysics Data System (ADS)

Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Orekhova, N.; Perkov, A.; Sasyuk, V.

2017-07-01

Here we present the summary of first years of operation and the first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (900 square degrees) or narrow (100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds.The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT also include faint meteors and artificial satellites.

Mini-MegaTORTORA Wide-Field Monitoring System with Subsecond Temporal Resolution: Observation of Transient Events

NASA Astrophysics Data System (ADS)

Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Orekhova, N.; Perkov, A.; Sasyuk, V.

2017-06-01

Here we present the summary of first years of operation and the first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (˜900 square degrees) or narrow (˜100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds.The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT include faint meteors and artificial satellites.

A study of starting time in great hard X-ray flares

NASA Technical Reports Server (NTRS)

Klein, K. L.; Pick, M.; Magun, A.

1986-01-01

An analysis of the starting time in ten great hard X-ray bursts observed with the X-Ray Burst Spectrometer (HXRBS) is presented. It is shown that the impulsive phase of nine of them is composed of a preflash phase, during which the burst is observed up to an energy limit ranging from some tens of keV to 200 keV, followed ten to some tens of seconds afterwards by a flash phase, where the count rate rises simultaneously in all detector channels. For two events strong gamma-ray line emission is observed and is shown to start close to the onset of the flash phase.

Correlated variations of UV and radio emissions during an outstanding Jovian auroral event

NASA Technical Reports Server (NTRS)

Prange, R.; Zarka, P.; Ballester, G. E.; Livengood, T. A.; Denis, L.; Carr, T.; Reyes, F.; Bame, S. J.; Moos, H. W.

1993-01-01

An exceptional Jovian aurora was detected in the FUV on December 21, 1990, by means of Vilspa and Goddard Space Flight Center (GFSC) International Ultraviolet Explorer (IUE) observations. This event included intensification by a factor of three between December 20 and 21, leading to the brightest aurora identified in the IUE data analyzed, and, in the north, to a shift of the emission peak towards larger longitudes. The Jovian radio emission simultaneously recorded at decameter wavelengths in Nancay also exhibits significant changes, from a weak and short-duration emission on December 20 to a very intense one, lasting several hours, on December 21. Confirmation of this intense radio event is also found in the observations at the University of Florida on December 21. The emissions are identified as right-handed Io-independent 'A' (or 'non Io-A') components from the northern hemisphere. The radio source region deduced from the Nancay observations lies, for both days, close to the UV peak emission, exhibiting in particular a similar shift of the source region toward larger longitudes from one day to the next. A significant broadening of the radio source was also observed and it is shown that on both days, the extent of the radio source closely followed the longitude range for which the UV brightness exceeds a given threshold. The correlated variations, both in intensity and longitude, strongly suggest that a common cause triggered the variation of the UV and radio emissions during this exceptional event. On one hand, the variation of the UV aurora could possibly be interpreted according to the Prange and Elkhamsi (1991) model of diffuse multicomponent auroral precipitation (electron and ion): it would arise from an increase in the precipitation rate of ions together with an inward shift of their precipitation locus from L approximately equal 10 to L approximately equal 6. On the other hand, the analysis of Ulysses observations in the upstream solar wind suggests that a significant disturbance in the solar wind, involving the generation of an interplanetary shock and the presence of a CME have interacted with the Jovian magnetosphere at about the time of the auroral event. Both arguments suggest that we may have observed for the first time a magnetic storm-type interaction in an outer planet magnetosphere, affecting simultaneously several auroral processes. Conversely, the observed relationship between the level of UV auroral activity and the detection of decameter emission (DAM), if it were a typical feature, might argue in favour of a more direct and permanent association between the auroral processes leading to UV and radio aurorae, possibly related to 'discrete-arc'-like activity and electron precipitation.

Flux transfer events at the dayside magnetopause: Transient reconnection or magnetosheath dynamic pressure pulses

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

Lockwood, M.

1991-04-01

The suggestion is discussed that characteristic particle and field signatures at the dayside magnetopause, termed flux transfer events, are, in at least some cases, due to transient solar wind and/or magnetosheath dynamic pressure increases, rather than time-dependent magnetic reconnection. It is found that most individual cases of FTEs observed by a single spacecraft can, at least qualitatively, be explained by the pressure pulse model, provided a few rather unsatisfactory features of the predictions are explained in terms of measurement uncertainties. The most notable exceptions to this are some two-regime observations made by two satellites simultaneously, one on either side ofmore » the magnetopause. However, this configuration has not been frequently achieved for sufficient time, such observations are rare, and the relevant tests are still not conclusive. The strongest evidence that FTEs are produced by magnetic reconnection is the dependence of their occurence on the north-south component of the interplanetary magnetic field (IMF) or of the magnetosheath field. The pressure pulse model provides an explanation for this dependence in the case of magnetosheath FTEs, but does not apply to magnetosphere FTEs. The only surveys of magnetosphere FTEs have not employed the simultaneous IMF, but have shown that their occurence is strongly dependent on the north-south component of the magnetosheath field, as observed earlier/later on the same magnetopause crossing. This paper employs statistics on the variability of the IMF orientation to investigate the effects of IMF changes between the times of the magnetosheath and FTE observations. It is shown that the previously published results are consistent with magnetospheric FTEs being entirely absent when the magentosheath field is northward.« less

Simultaneous Modeling of Gradual SEP Events at the Earth and the Mars

NASA Astrophysics Data System (ADS)

Hu, J.; Li, G.

2017-12-01

Solar Energetic Particles (SEP) event is the number one space hazard for spacecraft instruments and astronauts' safety. Recent studies have shown that both longitudinal and radial extent of SEP events can be very significant. In this work, we use the improved Particle Acceleration and Transport in the Heliosphere (iPATH) model to simulate gradual SEP events that have impacts upon both the Earth and the Mars. We follow the propagation of a 2D CME-driven shock. Particles are accelerated at the shock via the diffusive shock acceleration (DSA) mechanism. Transport of the escaped particles to the Earth and the Mars is then followed using a backward stochastic differential equation method. Perpendicular diffusion is considered in both the DSA and the transport process. Model results such as time intensity profile and energetic particle spectrum at the two locations are compared to understand the spatial extent of an SEP event. Observational data at the Earth and the Mars are also studied to validate the model.

Recent Advances in Observations of Ground-level Auroral Kilometric Radiation

NASA Astrophysics Data System (ADS)

Labelle, J. W.; Ritter, J.; Pasternak, S.; Anderson, R. R.; Kojima, H.; Frey, H. U.

2011-12-01

Recently LaBelle and Anderson [2011] reported the first definitive observations of AKR at ground level, confirmed through simultaneous measurements on the Geotail spacecraft and at South Pole Station, Antarctica. The initial observations consisted of three examples recorded in 2004. An Antarctic observing site is critical for observing ground level AKR which is obscured by man-made broadcast signals at northern hemisphere locations. Examination of 2008 austral winter radio data from Antarctic Automatic Geophysical Observatories (AGOs) of the Polar Experiment Network for Geospace Upper-atmosphere Investigations (PENGUIn) network and South Pole Station reveals 37 ground level AKR events on 23 different days, 30 of which are confirmed by correlation with AKR observed with the Geotail spacecraft. The location of the Geotail spacecraft appears to be a significant factor enabling coincident measurements. Six of the AKR events are detected at two or three ground-level observatories separated by approximately 500 km, suggesting that the events illuminate an area comparable to a 500-km diameter. For 14 events on ten nights, photometer and all-sky imager data from South Pole and AGOs were examined; in ten cases, locations of auroral arcs could be determined at the times of the events. In eight of those cases, the AKR was detected at observatories poleward of the auroral arcs, and in the other two cases the aurora was approximately overhead at the observatory where AKR was detected. These observations suggest that the AKR signals may be ducted to ground level along magnetic field lines rather than propagating directly from the AKR source region of approximately 5000 km altitude. Correlations between structures in the AKR and intensifications of auroral arcs are occasionally observed but are rare. The ground-level AKR events have a local time distribution similar to that of AKR observed from satellites, peaking in the pre-midnight to midnight sector. This data base of >30 events observed coincidentally at ground level and on the Geotail spacecraft, including several events detected at multiple ground stations, will provide a measurements of the ratio of the ground level intensity to that observed on the satellite, with the latter adjusted for distance. This ratio of intensities, not well-determined from the original three events [LaBelle and Anderson, 2011], places an important constraint on the generation mechanism. Reference: LaBelle, J., and R.R. Anderson (2011), Ground-level detection of Auroral Kilometric Radiation, Geophys. Res. Lett., 38, L04104, doi:10.1029/2010GL046411.

First Simultaneous Views of the Axial and Lateral Perspectives of a Coronal Mass Ejection

NASA Astrophysics Data System (ADS)

Cabello, I.; Cremades, H.; Balmaceda, L.; Dohmen, I.

2016-08-01

The different appearances exhibited by coronal mass ejections (CMEs) are believed to be in part the result of different orientations of their main axis of symmetry, consistent with a flux-rope configuration. There are observational reports of CMEs seen along their main axis (axial perspective) and perpendicular to it (lateral perspective), but no simultaneous observations of both perspectives from the same CME have been reported to date. The stereoscopic views of the telescopes onboard the Solar-Terrestrial Relations Observatory (STEREO) twin spacecraft, in combination with the views from the Solar and Heliospheric Observatory (SOHO) and the Solar Dynamics Observatory (SDO), allow us to study the axial and lateral perspectives of a CME simultaneously for the first time. In addition, this study shows that the lateral angular extent ( L) increases linearly with time, while the angular extent of the axial perspective ( D) presents this behavior only from the low corona to {≈} 5 R_{⊙}, where it slows down. The ratio L/D ≈ 1.6 obtained here as the average over several points in time is consistent with measurements of L and D previously performed on events exhibiting only one of the perspectives from the single vantage point provided by SOHO.

Complex effusive events at Kilauea as documented by the GOES satellite and remote video cameras

USGS Publications Warehouse

Harris, A.J.L.; Thornber, C.R.

1999-01-01

GOES provides thermal data for all of the Hawaiian volcanoes once every 15 min. We show how volcanic radiance time series produced from this data stream can be used as a simple measure of effusive activity. Two types of radiance trends in these time series can be used to monitor effusive activity: (a) Gradual variations in radiance reveal steady flow-field extension and tube development. (b) Discrete spikes correlate with short bursts of activity, such as lava fountaining or lava-lake overflows. We are confident that any effusive event covering more than 10,000 m2 of ground in less than 60 min will be unambiguously detectable using this approach. We demonstrate this capability using GOES, video camera and ground-based observational data for the current eruption of Kilauea volcano (Hawai'i). A GOES radiance time series was constructed from 3987 images between 19 June and 12 August 1997. This time series displayed 24 radiance spikes elevated more than two standard deviations above the mean; 19 of these are correlated with video-recorded short-burst effusive events. Less ambiguous events are interpreted, assessed and related to specific volcanic events by simultaneous use of permanently recording video camera data and ground-observer reports. The GOES radiance time series are automatically processed on data reception and made available in near-real-time, so such time series can contribute to three main monitoring functions: (a) automatically alerting major effusive events; (b) event confirmation and assessment; and (c) establishing effusive event chronology.

A Search for Meteoroid Lunar Impact Generated Electromagnetic Pulses

NASA Astrophysics Data System (ADS)

Kesaraju, Saiveena; Mathews, John D.; Vierinen, Juha; Perillat, Phil; Meisel, David D.

2016-11-01

Lunar white light flashes associated with meteoroid impacts are now regularly observed using modest optical instrumentation. In this paper, we hypothesize that the developing, optically-dense hot ejecta cloud associated with these hypervelocity impacts also produce an associated complex plasma component that rapidly evolves resulting in a highly-transient electro magnetic pulse (EMP) in the VHF/UHF spectral region. Discovery of the characteristics and event frequency of impact EMPs would prove interesting to meteoroid flux and complex plasma physics studies especially if EMPs from the same event are detected from at least two locations on the Earth with relative delays appropriate to the propagation paths. We describe a prototype observational search, conducted in May 2014, for meteoroid lunar-impact EMPs that was conducted using simultaneous, overlapping-band, UHF radio observations at the Arecibo (AO; Puerto Rico) and Haystack (HO, Massachusetts, USA) Observatories. Monostatic/bistatic lunar radar imaging observations were also performed with HO transmitting and HO/AO receiving to confirm tracking, the net delay, and the pointing/timing ephemeris at both observatories. Signal analysis was performed using time-frequency signal processing techniques. Although, we did not conclusively identify EMP returns, this search detected possible EMPs and we have confirmed the search paradigm and established the sensitivity of the AO-HO system in detecting the hypothesized events. We have also characterized the difficult radio-frequency interference environment surrounding these UHF observations. We discuss the wide range of terrestrial-origin, Moon-bounce signals that were observed which additionally validate the observational technique. Further observations are contemplated.

Optical tweezers and multiphoton microscopies integrated photonic tool for mechanical and biochemical cell processes studies

NASA Astrophysics Data System (ADS)

de Thomaz, A. A.; Faustino, W. M.; Fontes, A.; Fernandes, H. P.; Barjas-Castro, M. d. L.; Metze, K.; Giorgio, S.; Barbosa, L. C.; Cesar, C. L.

2007-09-01

The research in biomedical photonics is clearly evolving in the direction of the understanding of biological processes at the cell level. The spatial resolution to accomplish this task practically requires photonics tools. However, an integration of different photonic tools and a multimodal and functional approach will be necessary to access the mechanical and biochemical cell processes. This way we can observe mechanicaly triggered biochemical events or biochemicaly triggered mechanical events, or even observe simultaneously mechanical and biochemical events triggered by other means, e.g. electricaly. One great advantage of the photonic tools is its easiness for integration. Therefore, we developed such integrated tool by incorporating single and double Optical Tweezers with Confocal Single and Multiphoton Microscopies. This system can perform 2-photon excited fluorescence and Second Harmonic Generation microscopies together with optical manipulations. It also can acquire Fluorescence and SHG spectra of specific spots. Force, elasticity and viscosity measurements of stretched membranes can be followed by real time confocal microscopies. Also opticaly trapped living protozoas, such as leishmania amazonensis. Integration with CARS microscopy is under way. We will show several examples of the use of such integrated instrument and its potential to observe mechanical and biochemical processes at cell level.

Hard X-Ray Burst Detected From Caltech Plasma Jet Experiment Magnetic Reconnection Event

NASA Astrophysics Data System (ADS)

Marshall, Ryan S.; Bellan, Paul M.

2016-10-01

In the Caltech plasma jet experiment a 100 kA MHD driven jet becomes kink unstable leading to a Rayleigh-Taylor instability that quickly causes a magnetic reconnection event. Movies show that the Rayleigh-Taylor instability is simultaneous with voltage spikes across the electrodes that provide the current that drives the jet. Hard x-rays between 4 keV and 9 keV have now been observed using an x-ray scintillator detector mounted just outside of a kapton window on the vacuum chamber. Preliminary results indicate that the timing of the x-ray burst coincides with a voltage spike on the electrodes occurring in association with the Rayleigh-Taylor event. The x-ray signal accompanies the voltage spike and Rayleigh-Taylor event in approximately 50% of the shots. A possible explanation for why the x-ray signal is sometimes missing is that the magnetic reconnection event may be localized to a specific region of the plasma outside the line of sight of the scintillator. The x-ray signal has also been seen accompanying the voltage spike when no Rayleigh-Taylor is observed. This may be due to the interframe timing on the camera being longer than the very short duration of the Rayleigh-Taylor instability.

First NuSTAR Observations of Mrk 501 within a Radio to TeV Multi-Instrument Campaign

DOE PAGES

Furniss, Amy

2015-10-08

We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsähovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by amore » sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission.« less

FIRST NuSTAR OBSERVATIONS OF MRK 501 WITHIN A RADIO TO TeV MULTI-INSTRUMENT CAMPAIGN

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

Furniss, A.; Noda, K.; Boggs, S.

2015-10-10

We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsähovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by amore » sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission.« less

A Synoptic- and Planetary-Scale Analysis of Widespread North American Ice Storms

NASA Astrophysics Data System (ADS)

McCray, C.; Gyakum, J. R.; Atallah, E.

2017-12-01

Freezing rain can have devastating impacts, particularly when it persists for many hours. Predicting the precise temperature stratification necessary for long duration freezing rain events remains an important forecast challenge. To better elucidate the conditions responsible for the most severe events, we concentrate on surface observations of long-duration (6 or more hours) freezing rain events over North America from 1979-2016. Furthermore, we analyze cases in which multiple stations observe long-duration events simultaneously. Following these cases over successive days allows us to generate maps of freezing rain "tracks." We then categorize recurring geographic patterns to examine the meteorological conditions leading to these events. While freezing rain is most frequently observed in the northeastern United States and southeastern Canada, long-duration events have affected areas as far south as the Gulf Coast. Notably, a disproportionately large number of very long duration (18 or more hours) events have occurred in the Southern Plains states relative to the climatological annual frequency of freezing rain there. Classification of individual cases shows that most of these very long duration events are associated with a recurring pattern which produces freezing rain along a southwest-northeast swath from Texas/Oklahoma into the northeastern U.S. and eastern Canada. Storms classified within this pattern include the January 1998 and December 2013 ice storms. While this pattern is the most widespread, additional spatially extensive patterns occur. One of these areas extends from the Southern Plains eastward along the Gulf Coast to Georgia and the Carolinas. A third category of events extends from the Upper Midwest into the northeastern U.S. and southeastern Canada. The expansive areal extent and long duration of these events make them especially problematic. An analysis of the planetary- to synoptic-scale settings responsible for these cases and the differences among individual storms is performed to provide forecasters with additional tools/insight towards the prediction of these damaging weather events.

Characteristics of long recovery early VLF events observed by the North African AWESOME Network

NASA Astrophysics Data System (ADS)

Naitamor, S.; Cohen, M. B.; Cotts, B. R. T.; Ghalila, H.; Alabdoadaim, M. A.; Graf, K.

2013-08-01

Lightning strokes are capable of initiating disturbances in the lower ionosphere, whose recoveries persist for many minutes. These events are remotely sensed via monitoring subionospherically propagating very low frequency (VLF) transmitter signals, which are perturbed as they pass through the region above the lightning stroke. In this paper we describe the properties and characteristics of the early VLF signal perturbations, which exhibit long recovery times using subionospheric VLF transmitter data from three identical receivers located at Algiers (Algeria), Tunis (Tunisia), and Sebha (Libya). The results indicate that the observation of long recovery events depends strongly on the modal structure of the signal electromagnetic field and the distance from the disturbed region and the receiver or transmitter locations. Comparison of simultaneously collected data at the three sites indicates that the role of the causative lightning stroke properties (e.g., peak current and polarity), or that of transient luminous events may be much less important. The dominant parameter which determines the duration of the recovery time and amplitude appears to be the modal structure of the subionospheric VLF probe signal at the ionospheric disturbance, where scattering occurs, and the subsequent modal structure that propagates to the receiver location.

Sea level oscillations in coastal waters of the Buenos Aires province, Argentina

NASA Astrophysics Data System (ADS)

Dragani, W. C.; Mazio, C. A.; Nuñez, M. N.

2002-03-01

Sea level oscillations, with periods ranging from a few minutes to almost 2 h, have been observed at various tide stations located on the coast of Buenos Aires. Simultaneous records of sea level elevation measured in Mar de Ajó, Pinamar and Mar del Plata during 1982 have been spectrally analyzed. Significant spectral energy has been detected between 0.85 and 4.69 cycles per hour (cph) and the most energetic peaks have frequencies between 1.17 and 1.49 cph. Spectra, coherence, and phase difference have been analyzed for the most energetic event of the year. During that event, the most intensive spectral peak is at 1.17 cph for Mar de Ajó and Pinamar, and at 1.49 cph for Mar del Plata. Simultaneous total energy peaks at Mar de Ajó, Pinamar and Mar del Plata, and the coherence function estimated between Mar de Ajó and Pinamar suggests that sea level oscillations could be a regional phenomenon. The analyzed data suggest that sea level oscillations could be forced by atmospheric gravity waves associated with frontal passages.

Multi-instrument Observations of Transient Luminous Events Associated with a Small-scale Winter Thunderstorm

NASA Astrophysics Data System (ADS)

Kolmasova, I.; Santolik, O.; Spurny, P.; Borovicka, J.; Mlynarczyk, J.; Popek, M.; Lan, R.; Uhlir, L.; Diendorfer, G.; Slosiar, R.

2017-12-01

We present observations of transient luminous events (TLEs) produced by a small-scale winter thunderstorm which occurred on 2 April 2017 in the southwest of Czechia. Elves, sprites and associated positive lightning strokes have been simultaneously recorded by different observational techniques. Optical data include video recordings of TLEs from Nydek (Czechia) and data recorded by high time-resolution photometers at several stations of the Czech fireball network which measured the all-sky brightness originating from lightning return strokes. Electromagnetic data sets include 3-component VLF measurements conducted in Rustrel (France), 2-component ELF measurements recorded at the Hylaty station (Poland) and signal intensity variations of a VLF transmitter (DHO38, Rhauderfehn, Germany) recorded in Bojnice (Slovakia). Optical and electromagnetic data are completed by positions and peak currents of all strokes recorded during the observed thunderstorm by the EUCLID lightning detection network. We focus our analysis on positive lightning discharges with high peak currents and we compare properties of those which produced TLE with properties of discharges for which TLE was not detected. The current moment waveforms and charge moment changes associated with the TLE events are reconstructed from the ELF electromagnetic signals. Obtained current moment waveforms show excellent agreement with high time-resolution optical data.

The Formation and Evolution of Energetic Transient Proton Belts Near L = 3

NASA Astrophysics Data System (ADS)

Claudepierre, S. G.; Roeder, J. L.; Blake, J. B.; Fennell, J. F.

2011-12-01

Solar energetic particle (SEP) events are one of many space weather events that can be hazardous to spacecraft operating in the near-Earth plasma environment. During an SEP, energetic protons (~20 MeV) can penetrate deep into the magnetosphere, at times to very low L shells (L~3). Under some circumstances, these injected protons can become stably trapped and persist for many days, thus forming a new proton belt in a region that is typically devoid of energetic protons. This can serve as a potential unforeseen hazard for spacecraft operating in this region of geospace. We use recent observations from the Polar-CEPPAD investigation and HEO spacecraft to examine the formation and evolution of energetic transient proton belts near L = 3. We consider several events where transient proton belts are associated with storm-sudden commencements driven by interplanetary shocks. Angular distributions obtained from the CEPPAD-HIST sensor on-board the Polar spacecraft reveal features that are difficult to reconcile with standard trapped particle theory. For example, the pitch-angle distributions are observed to vary substantially on timescales faster than what would be expected for a diffusive mechanism. We compare the HIST observations with simultaneous measurements in HEO and explore possible explanations for the rapid changes observed in the angular distributions.

Microwave evidence for large-scale changes associated with a filament eruption

NASA Technical Reports Server (NTRS)

Kundu, M. R.; Schmahl, E. J.; Fu, Q.-J.

1989-01-01

VLA observations at 6 and 20 cm wavelengths taken on August 3, 1985 are presented, showing an eruptive filament event in which microwave emission originated in two widely separated regions during the disintegration of the filament. The amount of heat required for the enhancement is estimated. Near-simultaneous changes in intensity and polarization were observed in the western components of the northern and southern regions. It is suggested that large-scale magnetic interconnections permitted the two regions to respond similarly to an external energy or mass source involved in the disruption of the filament.

Single Top Quark Production at the Tevatron

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

Peters, Yvonne

2013-01-01

While the heaviest known elementary particle, the top quark, has been discovered in 1995 by the CDF and D0 collaborations in ttbar events, it took 14 more years until the observation of single top quark production. In this article, we discuss recent studies of single top quark production by the CDF and D0 collaborations at the Tevatron. In particular, we present the measurement of single top quark s- and t-channel production combined, the first observation of t-channel production, the simultaneous measurement of s- and t-channel production cross sections as well as the extraction of the CMK matrix element |Vtb}|.

The First Year of Robotic Science with MINERVA

NASA Astrophysics Data System (ADS)

McCrady, Nate; Johnson, John A.; Wright, Jason; Wittenmyer, Robert; Eastman, Jason; Beatty, Thomas G.; Bottom, Michael; Johnson, Samson

2016-01-01

Detection of low-mass exoplanets orbiting Sun-like stars requires high cadence, long time-baseline observations that are impossible to obtain on shared large telescopes. MINERVA is a dedicated observatory for exoplanet detection that consists of four robotic 0.7-meter PlaneWave telescopes located at Whipple Observatory on Mt Hopkins, Arizona. First light science began in May 2015 with photometric monitoring of transit and microlensing events. The four telescopes can observe different targets, or provide simultaneous multi-color light curves of a single event. We will add a purpose-built, temperature-stabilized, high precision iodine cell spectrometer from Callaghan Innovation in 2016 to facilitate velocimetric search for low-mass exoplanets around nearby stars. The flexibility of the MINERVA array provides a natural avenue for educational and public outreach activities. One telescope in the array can break formation to observe targets from a queue or respond to remote operations from astronomy courses at a partner institution. MINERVA is a collaboration among Harvard U., Penn State U., U. Montana, and U. New South Wales.

Simultaneous beta and gamma spectroscopy

DOEpatents

Farsoni, Abdollah T.; Hamby, David M.

2010-03-23

A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

Structure of high and low shear-stress events in a turbulent boundary layer

NASA Astrophysics Data System (ADS)

Gomit, G.; de Kat, R.; Ganapathisubramani, B.

2018-01-01

Simultaneous particle image velocimetry (PIV) and wall-shear-stress sensor measurements were performed to study structures associated with shear-stress events in a flat plate turbulent boundary layer at a Reynolds number Reτ≈4000 . The PIV field of view covers 8 δ (where δ is the boundary layer thickness) along the streamwise direction and captures the entire boundary layer in the wall-normal direction. Simultaneously, wall-shear-stress measurements that capture the large-scale fluctuations were taken using a spanwise array of hot-film skin-friction sensors (spanning 2 δ ). Based on this combination of measurements, the organization of the conditional wall-normal and streamwise velocity fluctuations (u and v ) and of the Reynolds shear stress (-u v ) can be extracted. Conditional averages of the velocity field are computed by dividing the histogram of the large-scale wall-shear-stress fluctuations into four quartiles, each containing 25% of the occurrences. The conditional events corresponding to the extreme quartiles of the histogram (positive and negative) predominantly contribute to a change of velocity profile associated with the large structures and in the modulation of the small scales. A detailed examination of the Reynolds shear-stress contribution related to each of the four quartiles shows that the flow above a low wall-shear-stress event carries a larger amount of Reynolds shear stress than the other quartiles. The contribution of the small and large scales to this observation is discussed based on a scale decomposition of the velocity field.

Ballistic protons in incoherent exclusive vector meson production as a measure of rare parton fluctuations at an electron-ion collider

DOE PAGES

Lappi, T.; Venugopalan, R.; Mantysaari, H.

2015-02-25

We argue that the proton multiplicities measured in Roman pot detectors at an electron ion collider can be used to determine centrality classes in incoherent diffractive scattering. Incoherent diffraction probes the fluctuations in the interaction strengths of multi-parton Fock states in the nuclear wavefunctions. In particular, the saturation scale that characterizes this multi-parton dynamics is significantly larger in central events relative to minimum bias events. As an application, we examine the centrality dependence of incoherent diffractive vector meson production. We identify an observable which is simultaneously very sensitive to centrality triggered parton fluctuations and insensitive to details of the model.

Episodic slow slip events in the Japan subduction zone before the 2011 Tohoku-Oki earthquake

NASA Astrophysics Data System (ADS)

Ito, Y.; Hino, R.; Kido, M.; Fujimoto, H.; Osada, Y.; Inazu, D.; Ohta, Y.; Iinuma, T.; Ohzono, M.; Mishina, M.; Miura, S.; Suzuki, K.; Tsuji, T.; Ashi, J.

2012-12-01

We describe two transient slow slip events that occurred before the 2011 Tohoku-Oki earthquake. The first transient crustal deformation, which occurred over a period of a week in November 2008, was recorded simultaneously using ocean-bottom pressure gauges and an on-shore volumetric strainmeter; this deformation has been interpreted as being an M6.8 episodic slow slip event. The second had a duration exceeding 1 month and was observed in February 2011, just before the 2011 Tohoku-Oki earthquake; the moment magnitude of this event reached 7.0. The two events preceded interplate earthquakes of magnitudes M6.1 (December 2008) and M7.3 (March 9, 2011), respectively; the latter is the largest foreshock of the 2011 Tohoku-Oki earthquake. Our findings indicate that these slow slip events induced increases in shear stress, which in turn triggered the interplate earthquakes. The slow slip event source area on the fault is also located within the downdip portion of the huge-coseismic-slip area of the 2011 earthquake. This demonstrates episodic slow slip and seismic behavior occurring on the same portions of the megathrust fault, suggesting that the faults undergo slip in slow slip events can also rupture seismically.

Episodic slow slip events in the Japan subduction zone before the 2011 Tohoku-Oki earthquake

NASA Astrophysics Data System (ADS)

Ito, Yoshihiro; Hino, Ryota; Kido, Motoyuki; Fujimoto, Hiromi; Osada, Yukihito; Inazu, Daisuke; Ohta, Yusaku; Iinuma, Takeshi; Ohzono, Mako; Miura, Satoshi; Mishina, Masaaki; Suzuki, Kensuke; Tsuji, Takeshi; Ashi, Juichiro

2013-07-01

We describe two transient slow slip events that occurred before the 2011 Tohoku-Oki earthquake. The first transient crustal deformation, which occurred over a period of a week in November 2008, was recorded simultaneously using ocean-bottom pressure gauges and an on-shore volumetric strainmeter; this deformation has been interpreted as being an M6.8 episodic slow slip event. The second had a duration exceeding 1 month and was observed in February 2011, just before the 2011 Tohoku-Oki earthquake; the moment magnitude of this event reached 7.0. The two events preceded interplate earthquakes of magnitudes M6.1 (December 2008) and M7.3 (March 9, 2011), respectively; the latter is the largest foreshock of the 2011 Tohoku-Oki earthquake. Our findings indicate that these slow slip events induced increases in shear stress, which in turn triggered the interplate earthquakes. The slow slip event source area on the fault is also located within the downdip portion of the huge-coseismic-slip area of the 2011 earthquake. This demonstrates episodic slow slip and seismic behavior occurring on the same portions of the megathrust fault, suggesting that the faults undergo slip in slow slip events can also rupture seismically.

Outflow off the Beaten Path: Low Energy (< keV) O+ Outflow Directly Into the Inner Magnetosphere as Observed by the Van Allen Probes and the Implications for Mid- and Low-Latitude Magnetosphere-Ionosphere Coupling

NASA Astrophysics Data System (ADS)

Gkioulidou, M.; Mitchell, D. G.; Ukhorskiy, S.; Ohtani, S.; Takahashi, K.

2017-12-01

The low-energy (eV to hundreds of eV) ion population in the inner magnetosphere, the warm plasma cloak, and in particular its heavy ion component, the O+ torus, is crucial to magnetospheric dynamics. Yet, although the effects of high latitude and cusp ionospheric O+ outflow and its subsequent transport and acceleration within the magnetotail and plasma sheet have been extensively studied, the source of low-energy O+ within the inner magnetosphere (already observed by the DE1 spacecraft in the 80s) remains a compelling open question. The HOPE instrument aboard each of the Van Allen Probes, moving in highly elliptical, equatorial orbits with apogee of 5.8 RE, has repeatedly detected low-energy O+ field-aligned enhancements. We present a comprehensive study of one such event, where low energy O+ field-aligned intensity enhancements were observed, both at small and large pitch angles, during a geomagnetic storm. The energy spectrogram exhibited a dispersive signature and a banded structure, features that our simple particle tracing simulation demonstrated are due to O+ ions outflowing from both hemispheres of the night-side ionosphere directly into the magnetosphere within L = 4, and subsequently bouncing from one hemisphere to the other. These outflows are associated with field-aligned Poynting flux enhancements and field-aligned electron beams, as observed at the Van Allen Probes location, revealing energy transport from the magnetosphere to ionosphere as well as simultaneous field-aligned electron heating. We also incorporate ionospheric measurements, such as field-aligned currents, as those are inferred by AMPERE data. The combination of unprecedented simultaneous magnetospheric and ionospheric observations allow us to investigate the processes that lead to an O+ outflow event from the low-latitude, night-side ionosphere directly into the inner magnetosphere. The ubiquity of such events in the Van Allen Probes data might reveal one of the sources for the O+ torus.

Multiplex polymerase chain reaction-capillary gel electrophoresis: a promising tool for GMO screening--assay for simultaneous detection of five genetically modified cotton events and species.

PubMed

Nadal, Anna; Esteve, Teresa; Pla, Maria

2009-01-01

A multiplex polymerase chain reaction assay coupled to capillary gel electrophoresis for amplicon identification by size and color (multiplex PCR-CGE-SC) was developed for simultaneous detection of cotton species and 5 events of genetically modified (GM) cotton. Validated real-time-PCR reactions targeting Bollgard, Bollgard II, Roundup Ready, 3006-210-23, and 281-24-236 junction sequences, and the cotton reference gene acp1 were adapted to detect more than half of the European Union-approved individual or stacked GM cotton events in one reaction. The assay was fully specific (<1.7% of false classification rate), with limit of detection values of 0.1% for each event, which were also achieved with simulated mixtures at different relative percentages of targets. The assay was further combined with a second multiplex PCR-CGE-SC assay to allow simultaneous detection of 6 cotton and 5 maize targets (two endogenous genes and 9 GM events) in two multiplex PCRs and a single CGE, making the approach more economic. Besides allowing simultaneous detection of many targets with adequate specificity and sensitivity, the multiplex PCR-CGE-SC approach has high throughput and automation capabilities, while keeping a very simple protocol, e.g., amplification and labeling in one step. Thus, it is an easy and inexpensive tool for initial screening, to be complemented with quantitative assays if necessary.

Mini-MegaTORTORA wide-field monitoring system with sub-second temporal resolution: observation of transient events

NASA Astrophysics Data System (ADS)

Karpov, S.; Beskin, G.; Biryukov, A.; Bondar, S.; Ivanov, E.; Katkova, E.; Perkov, A.; Sasyuk, V.

2016-06-01

Here we present a summary of first years of operation and first results of a novel 9-channel wide-field optical monitoring system with sub-second temporal resolution, Mini-MegaTORTORA (MMT-9), which is in operation now at Special Astrophysical Observatory on Russian Caucasus. The system is able to observe the sky simultaneously in either wide (~900 square degrees) or narrow (~100 square degrees) fields of view, either in clear light or with any combination of color (Johnson-Cousins B, V or R) and polarimetric filters installed, with exposure times ranging from 0.1 s to hundreds of seconds. The real-time system data analysis pipeline performs automatic detection of rapid transient events, both near-Earth and extragalactic. The objects routinely detected by MMT include faint meteors and artificial satellites. The pipeline for a longer time scales variability analysis is still in development.

Evaluation of the antiemetic efficacy of maropitant in dogs medicated with morphine and acepromazine.

PubMed

Lorenzutti, A Matías; Martín-Flores, Manuel; Litterio, Nicolás J; Himelfarb, Martín A; Zarazaga, M Pilar

2016-03-01

To evaluate whether maropitant (1 mg kg(-1)) injected subcutaneously (SC), administered simultaneously or 30 minutes prior to intramuscular (IM) administration of morphine (0.5 mg kg(-1)) and acepromazine (0.05 mg kg(-1)), reduces the incidence of salivation, retching and emesis in dogs. Randomized, controlled, prospective clinical trial. Sixty dogs scheduled for an ovariohysterectomy as part of a population control program. Dogs were randomly allocated to be administered maropitant (1 mg kg(-1)) SC simultaneously (group M0) or 30 minutes prior to (group M30) administration of morphine (0.5 mg kg(-1)) and acepromazine (0.05 mg kg(-1)) IM. A control group was administered normal saline (C) at T-30 and T0. Dogs were observed for 30 minutes after morphine-acepromazine administration. The occurrence of vomiting, retching and salivation were recorded, as well as the time to first emesis and the number of emetic events per dog. The occurrence of salivation was not different between the groups. Retching and vomiting occurred significantly less frequently in M30 than in the other two groups (p < 0.02). The number of emetic events was also significantly less for M30 than for the other two groups (p = 0.01). When emesis occurred, the time to the first emetic event was similar among the groups. Maropitant (1 mg kg(-1)) SC reduced the frequency of morphine-induced emesis by as much as 70% when administered 30 minutes in advance. Simultaneous administration of maropitant and morphine-acepromazine produced no measurable effect on the frequency of retching or vomiting. © 2015 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

Observations of Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

NASA Technical Reports Server (NTRS)

Wilson, L. B., III; Koval, A.; Szabo, Adam; Breneman, A.; Cattell, C. A.; Goetz, K.; Kellogg, P. J.; Kersten, K.; Kasper, J. C.; Maruca, B. A.;

Calibrated infrared ground/air radiometric spectrometer

NASA Astrophysics Data System (ADS)

Silk, J. K.; Schildkraut, Elliot Robert; Bauldree, Russell S.; Goodrich, Shawn M.

1996-06-01

The calibrated infrared ground/air radiometric spectrometer (CIGARS) is a new high performance, multi-purpose, multi- platform Fourier transform spectrometer (FPS) sensor. It covers the waveband from 0.2 to 12 micrometer, has spectral resolution as fine as 0.3 cm-1, and records over 100 spectra per second. Two CIGARS units are being used for observations of target signatures in the air or on the ground from fixed or moving platforms, including high performance jet aircraft. In this paper we describe the characteristics and capabilities of the CIGARS sensor, which uses four interchangeable detector modules (Si, InGaAs, InSb, and HgCdTe) and two optics modules, with internal calibration. The data recording electronics support observations of transient events, even without precise information on the timing of the event. We present test and calibration data on the sensitivity, spectral resolution, stability, and spectral rate of CIGARS, and examples of in- flight observations of real targets. We also discuss plans for adapting CIGARS for imaging spectroscopy observations, with simultaneous spectral and spatial data, by replacing the existing detectors with a focal plane array (FPA).

Simultaneous observations of solar sporadic radio emission by the radio telescopes UTR-2, URAN-2 and NDA within the frequency range 8-41MHz

NASA Astrophysics Data System (ADS)

Melnik, V. N.; Konovalenko, A. A.; Rucker, H. O.; Brazhenko, A. I.; Briand, C.; Dorovskyy, V. V.; Zarka, P.; Denis, L.; Bulatzen, V. G.; Frantzusenko, A. V.; Stanislavskyy, A. A.

2012-04-01

From 25 June till 12 August 2011 sporadic solar radio emission was observed simultaneously by three separate radio telescopes: UTR-2 (Kharkov, Ukraine), URAN-2 (Poltava, Ukraine) and NDA (Nancay, France). During these observations several type II bursts with double and triple harmonics were registered, as well as type II bursts with complex herringbone structure. The events of particular interest were type II bursts registered on 9 and 11 August 2011. These bursts had opposite sign of circular polarization at different parts of their dynamic spectra. In our opinion we registered the emissions, which came from the different parts of the shock propagating through the solar corona. We have observed also groups of type III bursts merged into one burst, type III bursts with triple harmonics and type III bursts with "split" polarization. In addition some unusual solar bursts were registered: storms of strange narrow-band (up to 500kHz) bursts with high polarization degree (about 80%), decameter spikes of extremely short durations (200-300ms), "tadpole-like" bursts with durations of 1-2s and polarization degree up to 60%.

The Splitting of Double-component Active Asteroid P/2016 J1 (PANSTARRS)

NASA Astrophysics Data System (ADS)

Moreno, F.; Pozuelos, F. J.; Novaković, B.; Licandro, J.; Cabrera-Lavers, A.; Bolin, Bryce; Jedicke, Robert; Gladman, Brett J.; Bannister, Michele T.; Gwyn, Stephen D. J.; Vereš, Peter; Chambers, Kenneth; Chastel, Serge; Denneau, Larry; Flewelling, Heather; Huber, Mark; Schunová-Lilly, Eva; Magnier, Eugene; Wainscoat, Richard; Waters, Christopher; Weryk, Robert; Farnocchia, Davide; Micheli, Marco

2017-03-01

We present deep imaging observations, orbital dynamics, and dust-tail model analyses of the double-component asteroid P/2016 J1 (J1-A and J1-B). The observations were acquired at the Gran Telescopio Canarias (GTC) and the Canada-France-Hawaii Telescope (CFHT) from mid-March to late July of 2016. A statistical analysis of backward-in-time integrations of the orbits of a large sample of clone objects of P/2016 J1-A and J1-B shows that the minimum separation between them occurred most likely ˜2300 days prior to the current perihelion passage, I.e., during the previous orbit near perihelion. This closest approach was probably linked to a fragmentation event of their parent body. Monte Carlo dust-tail models show that those two components became active simultaneously ˜250 days before the current perihelion, with comparable maximum loss rates of ˜0.7 and ˜0.5 kg s-1, and total ejected masses of 8 × 106 and 6 × 106 kg for fragments J1-A and J1-B, respectively. Consequently, the fragmentation event and the present dust activity are unrelated. The simultaneous activation times of the two components and the fact that the activity lasted 6-9 months or longer, strongly indicate ice sublimation as the most likely mechanism involved in the dust emission process.

Heart rate modulation in bystanding geese watching social and non-social events

PubMed Central

Wascher, Claudia A.F; Scheiber, Isabella B.R; Kotrschal, Kurt

2008-01-01

Simply observing other individuals interacting has been shown to affect subsequent behaviour and also hormones in ‘bystander’ individuals. However, immediate physiological responses of an observer have been hardly investigated. Here we present results on individuals' heart rate (HR) responses during various situations, which occur regularly in a flock of greylag geese (Anser anser, e.g. agonistic encounters, vehicles passing by). We recorded simultaneously HR and behaviour of 21 semi-tame free-roaming geese, equipped with fully implanted transmitters. We considered 304 social and 81 non-social events during which the focal individuals did not respond behaviourally. Independent of the spatial distance to the event, these HR responses were significantly greater in social contexts (e.g. departing or landing geese, agonistic interactions) than in non-social situations (e.g. vehicles passing by, thunder). Focal individuals showed a significantly higher maximum HR as well as a greater HR increase in response to agonistic interactions, in which the pair partner or a family member was involved, as compared with a non-affiliated goose. Also, HR was significantly higher when the bystander watched non-affiliated geese interacting, which were higher ranking than the focal. We conclude that these differences are due to different relevance of the recorded events for the focal individual, depending on the individuals involved in the observed interaction. PMID:18430645

Postoperative Stiffness Requiring Manipulation Under Anesthesia Is Significantly Reduced After Simultaneous Versus Staged Bilateral Total Knee Arthroplasty.

PubMed

Meehan, John P; Monazzam, Shafagh; Miles, Troy; Danielsen, Beate; White, Richard H

2017-12-20

For patients with symptomatic bilateral knee arthritis, it is unknown whether the risk of developing stiffness requiring manipulation under anesthesia postoperatively is higher or lower for those undergoing simultaneous bilateral total knee arthroplasty (TKA) compared with those having staged bilateral TKA. Therefore, we undertook this study to evaluate the risk of requiring manipulation under anesthesia in staged versus simultaneous bilateral TKA as well as patients undergoing unilateral TKA. We utilized the California Patient Discharge Database, which is linked with the California Emergency Department, Ambulatory Surgery, and master death file databases. Using a literature-based estimate of the number of patients who failed to undergo the second stage of a staged bilateral TKA, replacement cases were randomly selected from patients who had unilateral TKA and were matched on 8 clinical characteristics of the patients who had staged bilateral TKA. Hierarchical multivariate logistic regression was performed to determine the risk-adjusted odds of manipulation in patients undergoing unilateral TKA, staged bilateral TKA, and simultaneous bilateral TKA using yearly hospital TKA volume as a random effect. Adjustment was made to allow fair comparison of the outcome at 90 and 180 days of follow-up after staged compared with simultaneous bilateral TKA. During the time period from 2005 through 2013, the cumulative incidence of manipulation within 90 days was 2.14% for unilateral TKA (4,398 events per 205,744 patients), 2.11% for staged bilateral TKA (724 events per 34,352 patients), and 1.62% for simultaneous bilateral TKA (195 events per 12,013 patients). At 180 days of complete follow-up, the cumulative incidence of manipulation was 3.07% after unilateral TKA (6,313 events per 205,649 patients), 2.89% after staged bilateral TKAs (957 events per 33,169 patients), and 2.29% after simultaneous bilateral TKA (267 events per 11,653 patients). With multivariate analyses used to adjust for relevant risk factors, the 90-day odds ratio (OR) of undergoing manipulation after simultaneous bilateral TKA was significantly lower than that for unilateral TKA (OR = 0.70; 95% confidence interval [CI], 0.57 to 0.86) and staged bilateral TKA (OR = 0.71; 95% CI, 0.57 to 0.90). Similarly, at 180 days, the odds of undergoing manipulation were significantly lower after simultaneous bilateral TKA than after both unilateral TKA (OR = 0.71; 95% CI, 0.59 to 0.84) and staged bilateral TKA (OR = 0.76; 95% CI, 0.63 to 0.93). The frequency of manipulation was significantly associated with younger age, fewer comorbidities, black race, and the absence of obesity. Although the ORs were small (close to 1), simultaneous bilateral TKA had a significantly decreased rate of stiffness requiring manipulation under anesthesia at 90 days and 180 days after knee replacement compared with that after staged bilateral TKA and unilateral TKA. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Study of the underlying event at forward rapidity in pp collisions at $$ \\sqrt{s}=0.9,2.76,\\;\\mathrm{and}\\;7\\;\\mathrm{TeV} $$

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

Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.

The underlying event activity in proton-proton collisions at forward pseudo-rapidity (-6.6 < η < -5.2) is studied with the CMS detector at the LHC, using a novel observable: the ratio of the forward energy density, dE/dη, for events with a charged-particle jet produced at central pseudorapidity (|η jet| < 2) to the forward energy density for inclusive events. This forward energy density ratio is measured as a function of the central jet transverse momentum, p (T), at three different pp centre-of-mass energies (more » $$\\sqrt{s}$$ = 0.9, 2.76, and 7 TeV). In addition, the evolution of the forward energy density is studied in inclusive events and in events with a central jet. The results are compared to those of Monte Carlo event generators for pp collisions and are discussed in terms of the underlying event. Whereas the dependence of the forward energy density ratio on jet p T at each separately can be well reproduced by some models, all models fail to simultaneously describe the increase of the forward energy density with in both inclusive events and in events with a central jet.« less

Plasma properties of driver gas following interplanetary shocks observed by ISEE-3

NASA Technical Reports Server (NTRS)

Zwickl, R. D.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T.; Smith, E. J.

1983-01-01

Plasma fluid parameters calculated from solar wind and magnetic field data to determine the characteristic properties of driver gas following a select subset of interplanetary shocks were studied. Of 54 shocks observed from August 1978 to February 1980, 9 contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the average proton temperature. While helium enhancements were present downstream of the shock in all 9 of these events, only about half of them contained simultaneous changes in the two quantities. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in magnetic field magnitude with an unusually low variance, by a small decrease in the variance of the bulk velocity, and by an increase in the ratio of parallel to perpendicular temperature. The cold driver gas usually displayed a bidirectional flow of suprathermal solar wind electrons at higher energies.

Plasma properties of driver gas following interplanetary shocks observed by ISEE-3

NASA Technical Reports Server (NTRS)

Zwickl, R. D.; Ashbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T.; Smith, E. J.

1982-01-01

Plasma fluid parameters calculated from solar wind and magnetic field data obtained on ISEE 3 were studied. The characteristic properties of driver gas following interplanetary shocks was determined. Of 54 shocks observed from August 1978 to February 1980, nine contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the average proton temperature across a tangential discontinuity. While helium enhancements were present in all of nine of these events, only about half of them contained simultaneous changes in the two quantities. Often the He/H ratio changed over a period of minutes. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in magnetic field magnitude with an unusually low variance and by an increase in the ratio of parallel to perpendicular temperature. The drive gas usually displayed a bidirectional flow of suprathermal solar wind electrons at higher energies.

The complex and quaternionic quantum bit from relativity of simultaneity on an interferometer

NASA Astrophysics Data System (ADS)

Garner, Andrew J. P.; Müller, Markus P.; Dahlsten, Oscar C. O.

2017-12-01

The patterns of fringes produced by an interferometer have long been important testbeds for our best contemporary theories of physics. Historically, interference has been used to contrast quantum mechanics with classical physics, but recently experiments have been performed that test quantum theory against even more exotic alternatives. A physically motivated family of theories are those where the state space of a two-level system is given by a sphere of arbitrary dimension. This includes classical bits, and real, complex and quaternionic quantum theory. In this paper, we consider relativity of simultaneity (i.e. that observers may disagree about the order of events at different locations) as applied to a two-armed interferometer, and show that this forbids most interference phenomena more complicated than those of complex quantum theory. If interference must depend on some relational property of the setting (such as path difference), then relativity of simultaneity will limit state spaces to standard complex quantum theory, or a subspace thereof. If this relational assumption is relaxed, we find one additional theory compatible with relativity of simultaneity: quaternionic quantum theory. Our results have consequences for current laboratory interference experiments: they have to be designed carefully to avoid rendering beyond-quantum effects invisible by relativity of simultaneity.

The complex and quaternionic quantum bit from relativity of simultaneity on an interferometer.

PubMed

Garner, Andrew J P; Müller, Markus P; Dahlsten, Oscar C O

2017-12-01

The patterns of fringes produced by an interferometer have long been important testbeds for our best contemporary theories of physics. Historically, interference has been used to contrast quantum mechanics with classical physics, but recently experiments have been performed that test quantum theory against even more exotic alternatives. A physically motivated family of theories are those where the state space of a two-level system is given by a sphere of arbitrary dimension. This includes classical bits, and real, complex and quaternionic quantum theory. In this paper, we consider relativity of simultaneity (i.e. that observers may disagree about the order of events at different locations) as applied to a two-armed interferometer, and show that this forbids most interference phenomena more complicated than those of complex quantum theory. If interference must depend on some relational property of the setting (such as path difference), then relativity of simultaneity will limit state spaces to standard complex quantum theory, or a subspace thereof. If this relational assumption is relaxed, we find one additional theory compatible with relativity of simultaneity: quaternionic quantum theory. Our results have consequences for current laboratory interference experiments: they have to be designed carefully to avoid rendering beyond-quantum effects invisible by relativity of simultaneity.

A study of the dynamics of droughts in Northern Brazil: Observations, theory, and numerical experiments with a global atmospheric circulation model

NASA Technical Reports Server (NTRS)

Shukla, J.; Moura, A. D.

1980-01-01

The monthly mean sea surface temperature anomalies over tropical Altantic and rainfall anomalies over two selected stations for 25 years (1948-1972) were examined. It is found that the most severe drought events are associated with the simultaneous occurrence of warm sea surface temperature anomalies over north and cold sea surface temperature anomalies over south tropical Atlantic. Simultaneous occurrences of warm sea surface temperature anomaly at 15 deg N, 45 deg W and cold sea surface temperature anomaly at 15 deg S, 5 deg W were always associated with negative anomalies of rainfall, and vice versa. A simple primitive equation model is used to calculate the frictionally controlled and thermally driven circulation due to a prescribed heating function in a resting atmosphere.

Near-simultaneous great earthquakes at Tongan megathrust and outer rise in September 2009.

PubMed

Beavan, J; Wang, X; Holden, C; Wilson, K; Power, W; Prasetya, G; Bevis, M; Kautoke, R

2010-08-19

The Earth's largest earthquakes and tsunamis are usually caused by thrust-faulting earthquakes on the shallow part of the subduction interface between two tectonic plates, where stored elastic energy due to convergence between the plates is rapidly released. The tsunami that devastated the Samoan and northern Tongan islands on 29 September 2009 was preceded by a globally recorded magnitude-8 normal-faulting earthquake in the outer-rise region, where the Pacific plate bends before entering the subduction zone. Preliminary interpretation suggested that this earthquake was the source of the tsunami. Here we show that the outer-rise earthquake was accompanied by a nearly simultaneous rupture of the shallow subduction interface, equivalent to a magnitude-8 earthquake, that also contributed significantly to the tsunami. The subduction interface event was probably a slow earthquake with a rise time of several minutes that triggered the outer-rise event several minutes later. However, we cannot rule out the possibility that the normal fault ruptured first and dynamically triggered the subduction interface event. Our evidence comes from displacements of Global Positioning System stations and modelling of tsunami waves recorded by ocean-bottom pressure sensors, with support from seismic data and tsunami field observations. Evidence of the subduction earthquake in global seismic data is largely hidden because of the earthquake's slow rise time or because its ground motion is disguised by that of the normal-faulting event. Earthquake doublets where subduction interface events trigger large outer-rise earthquakes have been recorded previously, but this is the first well-documented example where the two events occur so closely in time and the triggering event might be a slow earthquake. As well as providing information on strain release mechanisms at subduction zones, earthquakes such as this provide a possible mechanism for the occasional large tsunamis generated at the Tonga subduction zone, where slip between the plates is predominantly aseismic.

Continuous and simultaneous measurements of precipitation and vapor isotopes over two monsoon seasons during 2016-2017 in Singapore

NASA Astrophysics Data System (ADS)

Jackisch, D.; He, S.; Ong, M. R.; Goodkin, N.

2017-12-01

Water isotopes are important tracers of climate dynamics and their measurement can provide valuable insights into the relationship between isotopes and atmospheric parameters and overall convective activities. While most studies provide data on daily or even monthly time scales, high-temporal in-situ stable isotope measurements are scarce, especially in the tropics. In this study, we presented δ18O and δ2H values in precipitation and vapor continuously and simultaneously measured using laser spectroscopy in Singapore during the 2016/2017 Northeast (NE) Asian monsoon and 2017 Southwest (SW) Asian monsoon. We found that δ-values of precipitation and vapor exhibit quite different patterns during individual events, although there is a significant correlation between the δ-values of precipitation and of vapor. δ-values in precipitation during individual precipitation events show a distinct V-shape pattern, with the lowest isotope values observed in the middle of the event. However, isotopes in water vapor mostly show an L-shape and are characterized by a gradual decrease with the onset of rainfall. The difference in δ-values of precipitation and vapor is generally constant during the early stage of the events but gradually increases near the end. It is likely that vapor and precipitation are closer to equilibrium at the early stage of a rain event, but diverge at the later stages. This divergence can be largely attributed to the evaporation of raindrops. We notice a frequent drop in d-excess of precipitation, whereas d-excess in vapor increases. In addition, a significant correlation exists between outgoing longwave radiation (OLR) and isotopes in both precipitation and vapor, suggesting an influence of regional convective activity.

End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change

PubMed Central

Petersen, Sierra V.; Dutton, Andrea; Lohmann, Kyger C.

2016-01-01

The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8±3.3 °C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change. PMID:27377632

End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change.

PubMed

Petersen, Sierra V; Dutton, Andrea; Lohmann, Kyger C

2016-07-05

The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8±3.3 °C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change.

End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change

NASA Astrophysics Data System (ADS)

Petersen, Sierra V.; Dutton, Andrea; Lohmann, Kyger C.

2016-07-01

The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8+/-3.3 °C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change.

Simultaneous Precipitation of Solar Protons and Relativistic Electrons as a New Factor Affecting the Earth's Atmosphere

NASA Astrophysics Data System (ADS)

Shirochkov, A. V.; Sokolov, S. N.

In the field of solar - terrestrial physics during the last decade there has been renewed interest in the effects produced in the Earth atmosphere and ionosphere by fluxes of precipitated highly relativistic electrons. A series of investigation on the subject (preferably by means of satellite measurements) was performed recently, which discussed different aspects of these phenomena called HRE events. More careful study of the HRE events revealed previously unnoticed geophysical phenomenon: a great majority of the solar proton events (SPE) were accompanied by simultaneous precipitation of relativistic electron fluxes. The studies of previous SPE events attributed their atmospheric and ionospheric effects entirely to the solar proton fluxes. It turned out that such an assumption is wrong. Therefore we have actually a new class of geophysical phenomena when the Earth's atmosphere and ionosphere experience combined impact of simultaneously precipitating fluxes of solar protons and relativistic electrons. If one takes into accounts effect of enhanced density of the solar wind during the SPEs (i.e. its dynamic pressure) the real situation during these combined events became more complicated. In this paper the effects during the storm of May 1992 are analyzed as an example of such unusual combination. The methods of separation of the effects produced by different precipitation particles are presented. Other similar events are considered to demonstrate that such complex events are not unique geophysical phenomena.

Optical gravitational lensing experiment: OGLE-1999-BUL-19 - the first multipeak parallax event

NASA Astrophysics Data System (ADS)

Smith, Martin C.; Mao, Shude; Woźniak, P.; Udalski, A.; Szymański, M.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Żebruń, K.

2002-10-01

We describe a highly unusual microlensing event, OGLE-1999-BUL-19. Unlike most standard microlensing events, this event exhibits multiple peaks in its light curve. The Einstein radius crossing time for this event is approximately 1 yr, which is unusually long. We show that the additional peaks in the light curve can be caused by the very small value for the relative transverse velocity of the lens projected on to the observer plane (). Since this value is significantly less than the speed of the orbit of the Earth around the Sun (v⊕~ 30km s-1), the motion of the Earth induces these multiple peaks in the light curve. This value for is the lowest velocity so far published and we believe that this is the first multiple-peak parallax event ever observed. We also found that the event can be somewhat better fitted by a rotating binary-source model, although this is to be expected since every parallax microlensing event can be exactly reproduced by a suitable binary-source model. A face-on rotating binary-lens model was also identified, but this provides a significantly worse fit. We conclude that the most likely cause for this multipeak behaviour is parallax microlensing rather than microlensing by a binary source. However, this event may be exhibiting a slight binary-source signature in addition to these parallax-induced multiple peaks. With spectroscopic observations it is possible to test this `parallax plus binary-source' hypothesis and (in the instance that the hypothesis turns out to be correct) to simultaneously fit both models and obtain a measurement of the lens mass. Furthermore, spectroscopic observations could also supply information regarding the lens properties, possibly providing another avenue for determining the lens mass. We also investigated the nature of the blending for this event, and found that the majority of the I-band blending is contributed by a source roughly aligned with the lensed source. This implies that most of the I-band blending is caused by light from the lens or a binary companion to the source. However, in the V band, there appears to be a second blended source 0.35 arcsec away from the lensed source. Hubble Space Telescope observations will be very useful for understanding the nature of the blends. We also suggest that a radial velocity survey of all parallax events will be very useful for further constraining the lensing kinematics and understanding the origins of these events and the excess of long events toward the bulge.

Comparing the behavioural impact of a nudge-based handwashing intervention to high-intensity hygiene education: a cluster-randomised trial in rural Bangladesh.

PubMed

Grover, Elise; Hossain, Mohammed Kamal; Uddin, Saker; Venkatesh, Mohini; Ram, Pavani K; Dreibelbis, Robert

2018-01-01

To determine the impact of environmental nudges on handwashing behaviours among primary school children as compared to a high-intensity hygiene education intervention. In a cluster-randomised trial (CRT), we compared the rates of handwashing with soap (HWWS) after a toileting event among primary school students in rural Bangladesh. Eligible schools (government run, on-site sanitation and water, no hygiene interventions in last year, fewer than 450 students) were identified, and 20 schools were randomly selected and allocated without blinding to one of four interventions, five schools per group: simultaneous handwashing infrastructure and nudge construction, sequential infrastructure then nudge construction, simultaneous infrastructure and high-intensity hygiene education (HE) and sequential handwashing infrastructure and HE. The primary outcome, incidence of HWWS after a toileting event, was compared between the intervention groups at different data collection points with robust-Poisson regression analysis with generalised estimating equations, adjusting for school-level clustering of outcomes. The nudge intervention and the HE intervention were found to be equally effective at sustained impact over 5 months post-intervention (adjusted IRR 0.81, 95% CI 0.61-1.09). When comparing intervention delivery timing, the simultaneous delivery of the HE intervention significantly outperformed the sequential HE delivery (adjusted IRR 1.58 CI 1.20-2.08), whereas no significant difference was observed between sequential and simultaneous nudge intervention delivery (adjusted IRR 0.75, 95% CI 0.48-1.17). Our trial demonstrates sustained improved handwashing behaviour 5 months after the nudge intervention. The nudge intervention's comparable performance to a high-intensity hygiene education intervention is encouraging. © 2017 John Wiley & Sons Ltd.

The Statistic Results of the ISUAL Lightning Survey

NASA Astrophysics Data System (ADS)

Chuang, Chia-Wen; Bing-Chih Chen, Alfred; Liu, Tie-Yue; Lin, Shin-Fa; Su, Han-Tzong; Hsu, Rue-Ron

2017-04-01

The ISUAL (Imager for Sprites and Upper Atmospheric Lightning) onboard FORMOSAT-2 is the first science payload dedicated to the study of the lightning-induced transient luminous events (TLEs). Transient events, including TLEs and lightning, were recorded by the intensified imager, spectrophotometer (SP), and array photometer (AP) simultaneously while their light variation observed by SP exceeds a programmed threshold. Therefore, ISUAL surveys not only TLEs but also lightning globally with a good spatial, temporal and spectral resolution. In the past 12 years (2004-2016), approximately 300,000 transient events were registered, and only 42,000 are classified as TLEs. Since the main mission objective is to explore the distribution and characteristics of TLEs, the remaining transient events, mainly lightning, can act as a long-term global lightning survey. These huge amount of events cannot be processed manually as TLEs do, therefore, a data pipeline is developed to scan lightning patterns and to derive their geolocation with an efficient algorithm. The 12-year statistic results including occurrence rate, global distribution, seasonal variation, and the comparison with the LIS/OTD survey are presented in this report.

Response of Jupiter's Aurora to Plasma Mass Loading Rate Monitored by the Hisaki Satellite During Io's Volcanic Event

NASA Astrophysics Data System (ADS)

Kimura, T.; Yoshioka, K.; Tsuchiya, F.; Hiraki, Y.; Tao, C.; Murakami, G.; Yamazaki, A.; Fujimoto, M.; Badman, S. V.; Delamere, P. A.; Bagenal, F.

2016-12-01

Plasma production and transfer processes in the planetary and stellar magnetospheres are essential for understanding the space environments around the celestial bodies. It is hypothesized that the mass of plasma loaded from Io's volcano to Jupiter's rotating magnetosphere is recurrently ejected as blobs from the distant tail region of the magnetosphere. The plasma ejections are possibly triggered by the magnetic reconnections, which are followed by the particle energization, bursty planetward plasma flow, and resultant auroral emissions. They are referred to as the 'energetic events'. However, there has been no evidence that the plasma mass loading actually causes the energetic events because of lack of the simultaneous observation of them. This study presents that the recurrent transient auroras, which are possibly representative for the energetic events, are closely associated with the mass loading. Continuous monitoring of the aurora and Io plasma torus indicates onset of the recurrent auroras when accumulation of the loaded plasma mass reaches the canonical total mass of the magnetosphere. This onset condition implies that the fully filled magnetosphere overflows the plasma mass accompanying the energetic events.

Adverse events in vaccinations for travelers - a 1-year prospective survey in a travel clinic in Germany.

PubMed

Slesak, Günther; Fleck, Ralf; Scherbaum, Helmut; Blumenstock, Gunnar; Schäfer, Johannes

2018-01-01

The study goal was to assess and compare adverse events (AE) of current vaccinations for travelers under 'real-life conditions'. A prospective observational online questionnaire study was performed from May 2015 till April 2016 in a travel clinic in Germany. Online questionnaire links were sent 1 week after the first vaccination date. Severity was rated on a scale from 1 to 5 (minor to very severe AE). Of 1357 vaccinees 781 (57.6%) responded to the questionnaire, corresponding to 1415 vaccinations (1-7 simultaneous vaccinations). Responders were more often female (f:m = 1.29:1). Main age groups were 20-29 years old (36.1%). Most frequent vaccinations were against rabies (277; chick embryo cell vaccine (CEC): 97, human diploid cell vaccine (HDC): 180), yellow fever (250), typhoid fever (198), meningococcal meningitis (126) and Japanese encephalitis (104). A total of 217 vaccinees (27.8%) reported AE; 82 (10.5%) rated AE as more severe (grade 3: 61, grade 4: 18, grade 5: 3). No life-threatening AE was reported. Of 157 systemic AE the most frequent were: fatigue (75), headaches (46) and pyrexia (31). Of 94 local AE most frequently reported were pain (66), myalgia (25) and swelling (12). AE after single vaccinations were more often associated with rabies vaccine (OR 2.2; 1.2-4.2). AE increased with the number of simultaneous vaccinations (single vaccination: 24.1%, 88/365; 2 vaccinations: 26.6%, 73/274, ≥3 vaccinations: 39.4%, 56/142, χ2 = 12.24, P = 0.002, CCorr = 0.18), but more severe AE showed no association with the number of vaccinations (χ2 = 5.55, P = 0.06, CCorr = 0.12). Single and simultaneous vaccinations were overall well tolerated. AE were reported more frequently with rabies vaccinations in single vaccinations. Increased numbers of simultaneous vaccinations led to some incremental AE but not to more severe AE. Simultaneous vaccinations should be encouraged to reduce missed opportunities for immunizations.

Great SEP events and space weather: 1. Experience of automatically searching for event beginnings; probabilities of false and missed events

NASA Astrophysics Data System (ADS)

Applbaum, David; Dorman, Lev; Pustil'Nik, Lev; Sternlieb, Abraham; Zagnetko, Alexander; Zukerman, Igor

It is well known that during great SEP events, fluxes of energetic particles can be so big that the memory of computers and other electronics in space may be destroyed, and satellites and spacecraft may cease to function. According to the NOAA Space Weather Prediction Cen-ter, the following scales constitute dangerous solar radiation storms: S5-extreme (flux level of particles with energy ∼ 10 MeV more than 105 ); S4 - severe(f luxmorethan104 ); andS3 - strong(f luxmorethan103 ). In these persiods, it is necessary to switch off some of the electronics for a few hours energy particles (meaning those with a few GeV/nucleon and higher), whose transportation to Earthfrom the S20 minutes after they accelerate and escape into the solar wind) than the main bulk of the smaller energy particle 60 minutes later). Here we describe the principles and experience of the automatic function of the "SEP - Search" program. The positive result, showing the exact beginning of an SEP event on the Emilio Segre Observ 10.8GV ), is determined now automatically by simultaneously increasing by 2.5 St.Dev. in two sections of the ne search "programnext uses 1-mindata for checking whether or not the observed increase reflects the beginning Research "automatically starts to work online. We determine also the probabilities of false and missed alerts.

Atmospheric mercury distribution in Northern Europe and in the Mediterranean region

NASA Astrophysics Data System (ADS)

Wängberg, I.; Munthe, J.; Pirrone, N.; Iverfeldt, Å.; Bahlman, E.; Costa, P.; Ebinghaus, R.; Feng, X.; Ferrara, R.; Gårdfeldt, K.; Kock, H.; Lanzillotta, E.; Mamane, Y.; Mas, F.; Melamed, E.; Osnat, Y.; Prestbo, E.; Sommar, J.; Schmolke, S.; Spain, G.; Sprovieri, F.; Tuncel, G.

Mercury species in air have been measured at five sites in Northwest Europe and at five coastal sites in the Mediterranean region during measurements at four seasons. Observed concentrations of total gaseous mercury (TGM), total particulate mercury (TPM) and reactive gaseous mercury (RGM) were generally slightly higher in the Mediterranean region than in Northwest Europe. Incoming clean Atlantic air seems to be enriched in TGM in comparison to air in Scandinavia. Trajectory analysis of events where high concentrations of TPM simultaneously were observed at sites in North Europe indicate source areas in Central Europe and provide evidence of transport of mercury on particles on a regional scale.

Anomalous winter-snow-amplified earthquake-induced disaster of the 2015 Langtang avalanche in Nepal

NASA Astrophysics Data System (ADS)

Fujita, Koji; Inoue, Hiroshi; Izumi, Takeki; Yamaguchi, Satoru; Sadakane, Ayako; Sunako, Sojiro; Nishimura, Kouichi; Immerzeel, Walter W.; Shea, Joseph M.; Kayastha, Rijan B.; Sawagaki, Takanobu; Breashears, David F.; Yagi, Hiroshi; Sakai, Akiko

2017-05-01

Coseismic avalanches and rockfalls, as well as their simultaneous air blast and muddy flow, which were induced by the 2015 Gorkha earthquake in Nepal, destroyed the village of Langtang. In order to reveal volume and structure of the deposit covering the village, as well as sequence of the multiple events, we conducted an intensive in situ observation in October 2015. Multitemporal digital elevation models created from photographs taken by helicopter and unmanned aerial vehicles reveal that the deposit volumes of the primary and succeeding events were 6.81 ± 1.54 × 106 and 0.84 ± 0.92 × 106 m3, respectively. Visual investigations of the deposit and witness statements of villagers suggest that the primary event was an avalanche composed mostly of snow, while the collapsed glacier ice could not be dominant source for the total mass. Succeeding events were multiple rockfalls which may have been triggered by aftershocks. From the initial deposit volume and the area of the upper catchment, we estimate an average snow depth of 1.82 ± 0.46 m in the source area. This is consistent with anomalously large snow depths (1.28-1.52 m) observed at a neighboring glacier (4800-5100 m a.s.l.), which accumulated over the course of four major snowfall events between October 2014 and the earthquake on 25 April 2015. Considering long-term observational data, probability density functions, and elevation gradients of precipitation, we conclude that this anomalous winter snow was an extreme event with a return interval of at least 100 years. The anomalous winter snowfall may have amplified the disastrous effects induced by the 2015 Gorkha earthquake in Nepal.

Tackle characteristics and injury in a cross section of rugby union football.

PubMed

McIntosh, Andrew S; Savage, Trevor N; McCrory, Paul; Fréchède, Bertrand O; Wolfe, Rory

2010-05-01

The tackle is the game event in rugby union most associated with injury. This study's main aims were to measure tackle characteristics from video using a qualitative protocol, to assess whether the characteristics differed by level of play, and to measure the associations between tackle characteristics and injury. A cohort study was undertaken. The cohort comprised male rugby players in the following levels: younger than 15 yr, 18 yr, and 20 yr, grade, and elite (Super 12 and Wallabies). All tackle events and technique characteristics were coded in 77 game halves using a standardized qualitative protocol. Game injuries and missed-game injuries were identified and correlated with tackle events. A total of 6618 tackle events, including 81 resulting in a game injury, were observed and coded in the 77 game halves fully analyzed (145 tackle events per hour). An increase in the proportion of active shoulder tackles was observed from younger than 15 yr (13%) to elite (31%). Younger players engaged in more passive tackles and tended to stay on their feet more than experienced players. Younger than 15 yr rugby players had a significantly lower risk of tackle game injury compared with elite players. No specific tackle technique was observed to be associated with a significantly increased risk of game injury. There was a greater risk of game injury associated with two or more tacklers involved in the tackle event, and the greatest risk was associated with simultaneous contact by tacklers, after adjusting for level of play. Tackle characteristics differed between levels of play. The number of tacklers and the sequence of tackler contact with the ball carrier require consideration from an injury prevention perspective.

Classification and Physical parameters EUV coronal jets with STEREO/SECCHI.

NASA Astrophysics Data System (ADS)

Nistico, Giuseppe; Bothmer, Volker; Patsourakos, Spiro; Zimbardo, Gaetano

In this work we present observations of EUV coronal jets, detected with the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suites of the two STEREO spacecraft. Starting from catalogues of polar and equatorial coronal hole jets (Nistico' et al., Solar Phys., 259, 87, 2009; Ann. Geophys. in press), identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008 when solar activity was at minimum, we perfom a detailed study of some events. A basic char-acterisation of the magnetic morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evo-lution. A classification of the events with respect to previous jet studies shows that amongst the 79 events, identified into polar coronal holes, there were 37 Eiffel tower -type jet events commonly interpreted as a small-scale ( 35 arcsec) magnetic bipole reconnecting with the ambi-ent unipolar open coronal magnetic fields at its looptops, 12 lambda-type jet events commonly interpreted as reconnection with the ambient field happening at the bipoles footpoints. Five events were termed micro-CME type jet events because they resembled classical three-part structured coronal mass ejections (CMEs) but on much smaller scales. The remainig 25 cases could not be uniquely classified. Thirty-one of the total number of events exhibited a helical magnetic field structure, indicative for a torsional motion of the jet around its axis of propaga-tion. The jet events are found to be also present in equatorial coronal holes. We also present the 3-D reconstruction, temperature, velocity, and density measurements of a number of jets during their evolution.

Magnetic field line draping in the plasma depletion layer

NASA Technical Reports Server (NTRS)

Sibeck, D. G.; Lepping, R. P.; Lazarus, A. J.

1990-01-01

Simultaneous IMP 8 solar wind and ISEE 1/2 observations for a northern dawn ISEE 1/2 magnetopause crossing on November 6, 1977. During this crossing, ISEE 1/2 observed quasi-periodic pulses of magnetosheathlike plasma on northward magnetic field lines. The ISEE 1/2 observations were originally interpreted as evidence for strong diffusion of magnetosheath plasma across the magnetopause and the Kelvin-Helmholtz instability at the inner edge of the low-latitude boundary layer. An alternate explanation, in terms of magnetic field merging and flux transfer events, has also been advocated. In this paper, a third interpretation is proposed in terms of quasi-periodic magnetopause motion which causes the satellites to repeatedly exit the magnetosphere and observe draped northward magnetosheath magnetic field lines in the plasma depletion layer.

F γ: A new observable for photon-hadron discrimination in hybrid air shower events

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

Niechciol, M.; Risse, M.; Ruehl, P.

To semore » arch for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. In this paper, we present a new observable, F γ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. F γ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known X max observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), F γ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable F γ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Finally and furthermore, F γ complements nicely to X max such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.« less

F γ: A new observable for photon-hadron discrimination in hybrid air shower events

DOE PAGES

Niechciol, M.; Risse, M.; Ruehl, P.; ...

2017-10-21

To semore » arch for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. In this paper, we present a new observable, F γ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. F γ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known X max observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), F γ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable F γ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Finally and furthermore, F γ complements nicely to X max such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.« less

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

Abeysekara, A. U.; Flinders, A.; Archambault, S.

Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the X-ray and gamma-ray bands, where the broadband spectral energy distributions usually peak. In this work, we report on three “target-of-opportunity” observations of Mrk 421, one of the brightest TeV blazars, triggered by a strong flaring event at TeV energies in 2014. These observations feature long, continuous, and simultaneous exposures with XMM-Newton (covering the X-ray and optical/ultraviolet bands) and VERITAS (covering the TeV gamma-ray band), along with contemporaneous observationsmore » from other gamma-ray facilities (MAGIC and Fermi -Large Area Telescope) and a number of radio and optical facilities. Although neither rapid flares nor significant X-ray/TeV correlation are detected, these observations reveal subtle changes in the X-ray spectrum of the source over the course of a few days. We search the simultaneous X-ray and TeV data for spectral hysteresis patterns and time delays, which could provide insight into the emission mechanisms and the source properties (e.g., the radius of the emitting region, the strength of the magnetic field, and related timescales). The observed broadband spectra are consistent with a one-zone synchrotron self-Compton model. We find that the power spectral density distribution at ≳4 × 10{sup −4} Hz from the X-ray data can be described by a power-law model with an index value between 1.2 and 1.8, and do not find evidence for a steepening of the power spectral index (often associated with a characteristic length scale) compared to the previously reported values at lower frequencies.« less

A Bayesian kriging approach for blending satellite and ground precipitation observations

USGS Publications Warehouse

Verdin, Andrew P.; Rajagopalan, Balaji; Kleiber, William; Funk, Christopher C.

2015-01-01

Drought and flood management practices require accurate estimates of precipitation. Gauge observations, however, are often sparse in regions with complicated terrain, clustered in valleys, and of poor quality. Consequently, the spatial extent of wet events is poorly represented. Satellite-derived precipitation data are an attractive alternative, though they tend to underestimate the magnitude of wet events due to their dependency on retrieval algorithms and the indirect relationship between satellite infrared observations and precipitation intensities. Here we offer a Bayesian kriging approach for blending precipitation gauge data and the Climate Hazards Group Infrared Precipitation satellite-derived precipitation estimates for Central America, Colombia, and Venezuela. First, the gauge observations are modeled as a linear function of satellite-derived estimates and any number of other variables—for this research we include elevation. Prior distributions are defined for all model parameters and the posterior distributions are obtained simultaneously via Markov chain Monte Carlo sampling. The posterior distributions of these parameters are required for spatial estimation, and thus are obtained prior to implementing the spatial kriging model. This functional framework is applied to model parameters obtained by sampling from the posterior distributions, and the residuals of the linear model are subject to a spatial kriging model. Consequently, the posterior distributions and uncertainties of the blended precipitation estimates are obtained. We demonstrate this method by applying it to pentadal and monthly total precipitation fields during 2009. The model's performance and its inherent ability to capture wet events are investigated. We show that this blending method significantly improves upon the satellite-derived estimates and is also competitive in its ability to represent wet events. This procedure also provides a means to estimate a full conditional distribution of the “true” observed precipitation value at each grid cell.

Gamma-Ray Bursts: An Overview of Recent Observational Progress

NASA Astrophysics Data System (ADS)

McKay, T. A.; Akerlof, C.; Kehoe, B.; Pawl, A.; Balsano, R.; Bloch, J.; Casperson, D.; Fletcher, S.; Gisler, G.; Hills, J.; Szymanski, J.; Wren, J.; Marshall, S.; Lee, B.

Gamma-ray bursts have, since their discovery in 1969, been the archetypal astrophysical mystery. Despite the detection of thousands of events, our knowledge of the origin and nature of GRBs remained minimal for nearly 30 years. Progress in understanding gamma-ray bursts has undergone explosive growth since the observation in 1997 of the first optical afterglow of a burst. The discovery of afterglows was followed in 1999 by the first simultaneous optical detection of a GRB. These discoveries constitute the beginning of a new field, the multiwavelength study of GRBs. We review here some highlights of what we have learned over the last two years, and look ahead towards an observational program likely to settle most of the remaining GRB questions.

Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

NASA Technical Reports Server (NTRS)

Wilson, L. B., III

2012-01-01

We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical interplanetary shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local magnetic field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the magnetic field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves.

How actions shape perception: learning action-outcome relations and predicting sensory outcomes promote audio-visual temporal binding

PubMed Central

Desantis, Andrea; Haggard, Patrick

2016-01-01

To maintain a temporally-unified representation of audio and visual features of objects in our environment, the brain recalibrates audio-visual simultaneity. This process allows adjustment for both differences in time of transmission and time for processing of audio and visual signals. In four experiments, we show that the cognitive processes for controlling instrumental actions also have strong influence on audio-visual recalibration. Participants learned that right and left hand button-presses each produced a specific audio-visual stimulus. Following one action the audio preceded the visual stimulus, while for the other action audio lagged vision. In a subsequent test phase, left and right button-press generated either the same audio-visual stimulus as learned initially, or the pair associated with the other action. We observed recalibration of simultaneity only for previously-learned audio-visual outcomes. Thus, learning an action-outcome relation promotes temporal grouping of the audio and visual events within the outcome pair, contributing to the creation of a temporally unified multisensory object. This suggests that learning action-outcome relations and the prediction of perceptual outcomes can provide an integrative temporal structure for our experiences of external events. PMID:27982063

How actions shape perception: learning action-outcome relations and predicting sensory outcomes promote audio-visual temporal binding.

PubMed

Desantis, Andrea; Haggard, Patrick

2016-12-16

To maintain a temporally-unified representation of audio and visual features of objects in our environment, the brain recalibrates audio-visual simultaneity. This process allows adjustment for both differences in time of transmission and time for processing of audio and visual signals. In four experiments, we show that the cognitive processes for controlling instrumental actions also have strong influence on audio-visual recalibration. Participants learned that right and left hand button-presses each produced a specific audio-visual stimulus. Following one action the audio preceded the visual stimulus, while for the other action audio lagged vision. In a subsequent test phase, left and right button-press generated either the same audio-visual stimulus as learned initially, or the pair associated with the other action. We observed recalibration of simultaneity only for previously-learned audio-visual outcomes. Thus, learning an action-outcome relation promotes temporal grouping of the audio and visual events within the outcome pair, contributing to the creation of a temporally unified multisensory object. This suggests that learning action-outcome relations and the prediction of perceptual outcomes can provide an integrative temporal structure for our experiences of external events.

Hodoscope readout system

DOEpatents

Lee, L.Y.

1973-12-01

A readout system has been provided for reading out a radiation multidetector device with a reduced number of signal sensors. A radiation hodoscope, such as an array of scintillation counters, multiwire proportional counter array, or a set of multidetectors which do not receive signals simultaneously, is divided into equal numbered groups. A first group of signal terminals is connected to the equal numbered groups of detectors so that a signal from any one of the detectors of a group will be fed to one of the first group of terminals. A second group of signal terminals is connected to the detector groups so that a signal from a particular numbered detector of each of the detector groups is connected to one of the second group of terminals. Both groups of signal terminals are, in turn, coupled to signal sensors so that when a signal is simultaneously observed in one of the first group of terminals and one of the second group of tenniinals the specific detector detecting a radiation event is determined. The sensors are arranged in such a manner that a binary code is developed from their outputs which can be stored in a digital storage means according to the location of the event in the multidetector device. (Official Gazette)

Variation of aerosol characteristics in the detail scale of time and space

NASA Astrophysics Data System (ADS)

Mukai, S.; Nakata, M.; Sano, I.

2012-04-01

In this work, we intend to demonstrate the spatial and temporal variation of atmospheric aerosols around AERONET/Osaka site. Osaka is the second big city in Japan and a typical Asian urban area. It is well known that the aerosol distribution in Asia is complicated due to the increasing emissions of anthropogenic aerosols in association with economic growth and in addition behavior of natural dusts significantly varies with the seasons. Therefore local spatially and temporally resolved measurements of atmospheric particles in Asian urban city are meaningful. We equip various ground measurement devices of atmosphere in the campus of Kinki University (KU). The data supplied by the Cimel instrument are analyzed with a standard AERONET (Aerosol Robotics Network) processing system. It provides us with Aerosol optical thickness (AOT), the Ångström exponent and so on. We set up a PM sampler and a standard instrument of NIES/LIDAR network attached to our AERONET site. The PM sampler provides particle information about the concentrations of PM2.5, PM10 and OBC separately. In addition to the simultaneous measurements, we make observation of the air quality at several locations in the neighbour-hood using portable sun-photometers (Solar-Light Company Microtops-2). The simultaneous measurements of aerosols and numerical model simulations indicate that the spatial and temporal factors influence the characterization of atmospheric particles especially in dust event. Then we observe the air quality at such several locations within a few 10 km area from KU, as Izumi and Nara, in ordinal days and dust days. Izumi site locates near industrial area and Nara is in the east of KU beyond the mountain-Ikoma. It is found from the simultaneous measurements at these three sites that AOT at Izumi in ordinal days is the highest and Nara's lowest. It indicates that the Ikoma-mountains block off the polluted air from the west. However in dust days, AOT at Nara is as large as that at Higashi-Osaka. We guess dust aerosols are transported over the mountains because dust aerosols exist higher than usual. In order to investigate change of aerosol properties before and after dust event, we analyze particulate matter with scanning electron microscope (SEM) coupled with energy dispersive X-ray analyzer (EDX). It is found from the scaling of particle size and ratio of major and minor axis for PM2.5 sampling on 21 March, 2010 when dust event occurred that at the peak of dust event nonspherical particles with large particle size are dominant. A componential analysis also presents temporal variation of aerosol properties. Sulfur is major component before dust comes but Si becomes major component with dust event.

Localizing gravitational wave sources with single-baseline atom interferometers

NASA Astrophysics Data System (ADS)

Graham, Peter W.; Jung, Sunghoon

2018-02-01

Localizing sources on the sky is crucial for realizing the full potential of gravitational waves for astronomy, astrophysics, and cosmology. We show that the midfrequency band, roughly 0.03 to 10 Hz, has significant potential for angular localization. The angular location is measured through the changing Doppler shift as the detector orbits the Sun. This band maximizes the effect since these are the highest frequencies in which sources live for several months. Atom interferometer detectors can observe in the midfrequency band, and even with just a single baseline they can exploit this effect for sensitive angular localization. The single-baseline orbits around the Earth and the Sun, causing it to reorient and change position significantly during the lifetime of the source, and making it similar to having multiple baselines/detectors. For example, atomic detectors could predict the location of upcoming black hole or neutron star merger events with sufficient accuracy to allow optical and other electromagnetic telescopes to observe these events simultaneously. Thus, midband atomic detectors are complementary to other gravitational wave detectors and will help complete the observation of a broad range of the gravitational spectrum.

Simultaneous EEG and diffuse optical imaging of seizure-related hemodynamic activity in the newborn infant brain

NASA Astrophysics Data System (ADS)

Hebden, Jeremy C.; Cooper, Robert J.; Gibson, Adam; Everdell, Nick; Austin, Topun

2012-06-01

An optical imaging system has been developed which uses measurements of diffusely reflected near-infrared light to produce maps of changes in blood flow and oxygenation occurring within the cerebral cortex. Optical sources and detectors are coupled to the head via an array of optical fibers, on a probe held in contact with the scalp, and data is collected at a rate of 10 Hz. A clinical electroencephalography (EEG) system has been integrated with the optical system to enable simultaneous observation of electrical and hemodynamic activity in the cortex of neurologically compromised newborn infants diagnosed with seizures. Studies have made a potentially critically important discovery of previously unknown transient hemodynamic events in infants treated with anticonvulsant medication. We observed repeated episodes of small increases in cortical oxyhemoglobin concentration followed by a profound decrease in 3 of 4 infants studied, each with cerebral injury who presented with neonatal seizures. This was not accompanied by clinical or EEG seizure activity and was not present in nineteen matched controls. The underlying cause of these changes is currently unknown. We tentatively suggest that our results may be associated with a phenomenon known as cortical spreading depolarization, not previously observed in the infant brain.

Analysis of a rapid increase of stratospheric ozone during late austral summer 2008 over Kerguelen (49.4° S, 70.3° E)

NASA Astrophysics Data System (ADS)

Bencherif, H.; El Amraoui, L.; Kirgis, G.; Leclair de Bellevue, J.; Hauchecorne, A.; Mzé, N.; Portafaix, T.

2010-07-01

This paper reports on an increase of ozone event observed over Kerguelen (49.4° S, 70.3° E) in relationship with large-scale isentropic transport. It is evidenced from ground-based observations, together with satellite global observations and assimilated fields. The study is based on the analyses of the first ozonesonde experiment never recorded at the Kerguelen site in the framework of a French campaign called ROCK that took place from April to August 2008. Comparisons and interpretations of the observed event are supported by co-localised SAOZ observations, by global mapping of tracers (O3, N2O and columns of O3) from Aura/MLS and Aura/OMI experiments, and by model simulations of Ertel Potential Vorticity initialised by ECMWF (European Centre for Medium-Range Weather Forecasts) data reanalyses. Satellite and ground-based observational data revealed a consistent increase of ozone in the local stratosphere by mid-April 2008. Additionally, Ozone (O3) and nitrous oxide (N2O) profiles obtained during January-May 2008 by the Microwave Lamb Sounder (MLS) aboard the Aura satellite are assimilated into MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle), a global three-dimensional chemistry transport model of Météo-France. The assimilated total O3 values are consistent with SAOZ ground observations (within ±5%), and isentropic distributions of O3 are matching well with maps of advected potential vorticity (APV) derived from the MIMOSA model, a high-resolution advection transport model, and from ECMWF reanalysis. The studied event seems to be related to isentropic transport of air masses that took place simultaneously in the lower- and middle-stratosphere, respectively from the polar region and from tropics to the mid-latitudes. In fact, the studied ozone increase by mid April 2008 results simultaneously: (1) from an equator-ward departure of polar air masses characterised with a high-ozone layer in the lower stratosphere (nearby the 475 K isentropic level), and (2) from a reverse isentropic transport from tropics to mid- and high-latitudes in the upper stratosphere (nearby the 700 K level). The increase of ozone observed over Kerguelen from the 16-April ozonesonde profile is then attributed to a concomitant isentropic transport of ozone in two stratospheric layers: the tropical air moving southward and reaches over Kerguelen in the upper stratosphere, and the polar air passing over the same area but in the lower stratosphere.

Simultaneous investigation of intracellular Ca2+ increase and morphological events upon fertilization in the sand dollar egg.

PubMed

Hamaguchi, Y; Hamaguchi, M S

1990-06-01

An increase in intracellular Ca2+ concentration ([Ca2+]) and morphological were simultaneously observed by epifluorescence and differential interference contrast (DIC) microscopy during fertilization of the sand dollar, Clypeaster japonicus. [Ca2+], which was detected by a Ca2+ indicator, Fluo-3, initially increased just beneath the sperm-attached site on the egg surface 8.6 sec after attachment. The increase spread into the egg as a concentric sphere to the egg center and, thereafter, propagated in the egg cytoplasm as a planar wave rather than a spherical wave. It reached the site opposite the initiation site across the egg 24.2 sec after initiation. The fertilization envelope (FE) began to elevate 10.3 sec after the initiation of the increase in [Ca2+] and 21.2 sec after sperm attachment.

The Splitting of Double-component Active Asteroid P/2016 J1 (PANSTARRS)

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

Moreno, F.; Pozuelos, F. J.; Novaković, B.

We present deep imaging observations, orbital dynamics, and dust-tail model analyses of the double-component asteroid P/2016 J1 (J1-A and J1-B). The observations were acquired at the Gran Telescopio Canarias (GTC) and the Canada–France–Hawaii Telescope (CFHT) from mid-March to late July of 2016. A statistical analysis of backward-in-time integrations of the orbits of a large sample of clone objects of P/2016 J1-A and J1-B shows that the minimum separation between them occurred most likely ∼2300 days prior to the current perihelion passage, i.e., during the previous orbit near perihelion. This closest approach was probably linked to a fragmentation event of theirmore » parent body. Monte Carlo dust-tail models show that those two components became active simultaneously ∼250 days before the current perihelion, with comparable maximum loss rates of ∼0.7 and ∼0.5 kg s{sup −1}, and total ejected masses of 8 × 10{sup 6} and 6 × 10{sup 6} kg for fragments J1-A and J1-B, respectively. Consequently, the fragmentation event and the present dust activity are unrelated. The simultaneous activation times of the two components and the fact that the activity lasted 6–9 months or longer, strongly indicate ice sublimation as the most likely mechanism involved in the dust emission process.« less

Cognitive responses and cortical oscillatory processing at various stereoscopic depths - a simultaneous EEG/MEG study.

PubMed

Cho, Hohyun; Kang, Min-Koo; Ahn, Sangtae; Kwon, Moonyoung; Yoon, Kuk-Jin; Kim, Kiwoong; Jun, Sung Chan

2017-01-01

Due to the recent explosion in various forms of 3D content, the evaluation of such content from a neuroscience perspective is quite interesting. However, existing investigations of cortical oscillatory responses in stereoscopic depth perception are quite rare. Therefore, we investigated spatiotemporal and spatio-temporo-spectral features at four different stereoscopic depths within the comfort zone. We adopted a simultaneous EEG/MEG acquisition technique to collect the oscillatory responses of eight participants. We defined subject-specific retinal disparities and designed a single trial-based stereoscopic viewing experimental paradigm. In the group analysis, we observed that, as the depth increased from Level 1 to Level 3, there was a time-locked increase in the N200 component in MEG and the P300 component in EEG in the occipital and parietal areas, respectively. In addition, initial alpha and beta event-related desynchronizations (ERD) were observed at approximately 500 to 1000 msec, while theta, alpha, and beta event-related synchronizations (ERS) appeared at approximately 1000 to 2000 ms. Interestingly, there was a saturation point in the increase in cognitive responses, including N200, P300, and alpha ERD, even when the depth increased only within the comfort zone. Meanwhile, the magnitude of low beta ERD decreased in the dorsal pathway as depth increased. From these findings, we concluded that cognitive responses are likely to become saturated in the visual comfort zone, while perceptual load may increase with depth.

Three-dimensional models of P wave velocity and P-to-S velocity ratio in the southern central Andes by simultaneous inversion of local earthquake data

NASA Astrophysics Data System (ADS)

Graeber, Frank M.; Asch, Günter

1999-09-01

The PISCO'94 (Proyecto de Investigatión Sismológica de la Cordillera Occidental, 1994) seismological network of 31 digital broad band and short-period three-component seismometers was deployed in northern Chile between the Coastal Cordillera and the Western Cordillera. More than 5300 local seismic events were observed in a 100 day period. A subset of high-quality P and S arrival time data was used to invert simultaneously for hypocenters and velocity structure. Additional data from two other networks in the region could be included. The velocity models show a number of prominent anomalies, outlining an extremely thickened crust (about 70 km) beneath the forearc region, an anomalous crustal structure beneath the recent magmatic arc (Western Cordillera) characterized by very low velocities, and a high-velocity slab. A region of an increased Vp/Vs ratio has been found directly above the Wadati-Benioff zone, which might be caused by hydration processes. A zone of lower than average velocities and a high Vp/Vs ratio might correspond to the asthenospheric wedge. The upper edge of the Wadati-Benioff zone is sharply defined by intermediate depth hypocenters, while evidence for a double seismic zone can hardly be seen. Crustal events between the Precordillera and the Western Cordillera have been observed for the first time and are mainly located in the vicinity of the Salar de Atacama down to depths of about 40 km.

A study of simultaneous scintillation observations by Chinese FY-2 geostationary meteorological satellite and VHF coherent radar measurements over South China

NASA Astrophysics Data System (ADS)

Zuo, X.; Yu, T.; Xia, C.

2016-12-01

It's a good place for South China to monitor ionospheric scintillation, which are situated near the northern crest of the equatorial ionosphere anomaly. The temporal variation characteristics of Amplitude scintillations of Chinese FY-2 geostationary meteorological satellite (86.5°E) observed at Guangzhou (23.2°N, 113.3°E, dip 18°N) during the period from July 2011 to June 2013 are present. The scintillation occurrence and intensity increase dramatically at September and October in FY-2 satellite link. The scintillation observations of FY-2 geostationary satellite observed at Guangzhou and simultaneous VHF (47.5MHz) coherent radar measurements from Sanya (18.3°N, 109.6°E, dip 13°N) during equinoctial months of 2011 and 2012 are used for a coordinated study for the relationship between the L-band scintillation patches on the propagation path of FY-2 satellite and the extended 3-m irregularity structures known as plumes over South China. The results showed good coincidence of the plumes with scintillation patches in most events. In case study, the zonal drift velocity of the irregularities was estimated by comparison of the onset times of the scintillation and plume and the irregularities were found to drift eastwards at a speed ranging about tens of meters to one hundred meters per second. From the derived value of drift speed and duration of scintillation events, the irregularity patches were found to have east-west extent about a few hundred kilometers. On the other hand, if the plumes on the radar maps occurred at lower altitudes, the associated irregularities would not be able to reach the IPP of the satellite and generate L-band scintillations there. Weak scintillations were observed on FY-2 link without any plume structure on radar backscatter maps occasionally.

Source parameter inversion of compound earthquakes on GPU/CPU hybrid platform

NASA Astrophysics Data System (ADS)

Wang, Y.; Ni, S.; Chen, W.

2012-12-01

Source parameter of earthquakes is essential problem in seismology. Accurate and timely determination of the earthquake parameters (such as moment, depth, strike, dip and rake of fault planes) is significant for both the rupture dynamics and ground motion prediction or simulation. And the rupture process study, especially for the moderate and large earthquakes, is essential as the more detailed kinematic study has became the routine work of seismologists. However, among these events, some events behave very specially and intrigue seismologists. These earthquakes usually consist of two similar size sub-events which occurred with very little time interval, such as mb4.5 Dec.9, 2003 in Virginia. The studying of these special events including the source parameter determination of each sub-events will be helpful to the understanding of earthquake dynamics. However, seismic signals of two distinctive sources are mixed up bringing in the difficulty of inversion. As to common events, the method(Cut and Paste) has been proven effective for resolving source parameters, which jointly use body wave and surface wave with independent time shift and weights. CAP could resolve fault orientation and focal depth using a grid search algorithm. Based on this method, we developed an algorithm(MUL_CAP) to simultaneously acquire parameters of two distinctive events. However, the simultaneous inversion of both sub-events make the computation very time consuming, so we develop a hybrid GPU and CPU version of CAP(HYBRID_CAP) to improve the computation efficiency. Thanks to advantages on multiple dimension storage and processing in GPU, we obtain excellent performance of the revised code on GPU-CPU combined architecture and the speedup factors can be as high as 40x-90x compared to classical cap on traditional CPU architecture.As the benchmark, we take the synthetics as observation and inverse the source parameters of two given sub-events and the inversion results are very consistent with the true parameters. For the events in Virginia, USA on 9 Dec, 2003, we re-invert source parameters and detailed analysis of regional waveform indicates that Virginia earthquake included two sub-events which are Mw4.05 and Mw4.25 at the same depth of 10km with focal mechanism of strike65/dip32/rake135, which are consistent with previous study. Moreover, compared to traditional two-source model method, MUL_CAP is more automatic with no need for human intervention.

Shallow and deep creep events observed and quantified with strainmeters along the San Andreas Fault near Parkfield

NASA Astrophysics Data System (ADS)

Mencin, D.; Hodgkinson, K. M.; Mattioli, G. S.; Johnson, W.; Gottlieb, M. H.; Meertens, C. M.

2016-12-01

Three-component strainmeter data from numerous borehole strainmeters (BSM) along the San Andreas Fault (SAF), including those that were installed and maintained as part of the EarthScope Plate Boundary Observatory (PBO), demonstrate that the characteristics of creep propagation events with sub-cm slip amplitudes can be quantified for slip events at 10 km source-to-sensor distances. The strainmeters are installed at depths of approximately 100 - 250 m and record data at a rate of 100 samples per second. Noise levels at periods of less than a few minutes are 10-11 strain, and for periods in the bandwidth hours to weeks, the periods of interest in the search for slow slip events, are of the order of 10-8 to 10-10 strain. Strainmeters, creepmeters, and tiltmeters have been operated along the San Andreas Fault, observing creep events for decades. BSM data proximal to the SAF cover a significant temporal portion of the inferred earthquake cycle along this portion of the fault. A single instrument is capable of providing broad scale constraints of creep event asperity size, location, and depth and moreover can capture slow slip, coseismic rupture as well as afterslip. The synthesis of these BSM data presents a unique opportunity to constrain the partitioning between aseismic and seismic slip on the central SAF. We show that the creepmeters confirm that creep events that are imaged by the strainmeters, previously catalogued by the authors, are indeed occurring on the SAF, and are simultaneously being recorded on local creepmeters. We further show that simple models allow us to loosely constrain the location and depth of the creep event on the fault, even with a single instrument, and to image the accumulation and behavior of surface as well as crustal creep with time.

Statistical Searches for Microlensing Events in Large, Non-uniformly Sampled Time-Domain Surveys: A Test Using Palomar Transient Factory Data

NASA Astrophysics Data System (ADS)

Price-Whelan, Adrian M.; Agüeros, Marcel A.; Fournier, Amanda P.; Street, Rachel; Ofek, Eran O.; Covey, Kevin R.; Levitan, David; Laher, Russ R.; Sesar, Branimir; Surace, Jason

2014-01-01

Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its ~20,000 deg2 footprint. While the median 7.26 deg2 PTF field has been imaged ~40 times in the R band, ~2300 deg2 have been observed >100 times. We use PTF data to study the trade off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a selection method using this statistic and apply it to data from fields with >10 R-band observations, 1.1 × 109 light curves, uncovering three candidate microlensing events. We lack simultaneous, multi-color photometry to confirm these as microlensing events. However, their number is consistent with predictions for the event rate in the PTF footprint over the survey's three years of operations, as estimated from near-field microlensing models. This work can help constrain all-sky event rate predictions and tests microlensing signal recovery in large data sets, which will be useful to future time-domain surveys, such as that planned with the Large Synoptic Survey Telescope.

Electrophysiological correlates of forming memories for faces, names, and face-name associations.

PubMed

Guo, Chunyan; Voss, Joel L; Paller, Ken A

2005-02-01

The ability to put a name to a face is a vital aspect of human interaction, but many people find this extremely difficult, especially after being introduced to someone for the first time. Creating enduring associations between arbitrary stimuli in this manner is also a prime example of what patients with amnesia find most difficult. To help develop a better understanding of this type of memory, we sought to obtain measures of the neural events responsible for successfully forming a new face-name association. We used event-related potentials (ERPs) extracted from high-density scalp EEG recordings in order to compare (1) memory for faces, (2) memory for names, and (3) memory for face-name associations. Each visual face appeared simultaneously with a unique spoken name. Signals observed 200-800 ms after the onset of face-name pairs predicted subsequent memory for faces, names, or face-name associations. Difference potentials observed as a function of subsequent memory performance were not identical for these three memory tests, nor were potentials predicting associative memory equivalent to the sum of potentials predicting item memory, suggesting that different neural events at the time of encoding are relevant for these distinct aspects of remembering people.

Vacillation, indecision and hesitation in moment-by-moment decoding of monkey motor cortex

PubMed Central

Kaufman, Matthew T; Churchland, Mark M; Ryu, Stephen I; Shenoy, Krishna V

2015-01-01

When choosing actions, we can act decisively, vacillate, or suffer momentary indecision. Studying how individual decisions unfold requires moment-by-moment readouts of brain state. Here we provide such a view from dorsal premotor and primary motor cortex. Two monkeys performed a novel decision task while we recorded from many neurons simultaneously. We found that a decoder trained using ‘forced choices’ (one target viable) was highly reliable when applied to ‘free choices’. However, during free choices internal events formed three categories. Typically, neural activity was consistent with rapid, unwavering choices. Sometimes, though, we observed presumed ‘changes of mind’: the neural state initially reflected one choice before changing to reflect the final choice. Finally, we observed momentary ‘indecision’: delay forming any clear motor plan. Further, moments of neural indecision accompanied moments of behavioral indecision. Together, these results reveal the rich and diverse set of internal events long suspected to occur during free choice. DOI: http://dx.doi.org/10.7554/eLife.04677.001 PMID:25942352

Scanning superlens microscopy for non-invasive large field-of-view visible light nanoscale imaging

NASA Astrophysics Data System (ADS)

Wang, Feifei; Liu, Lianqing; Yu, Haibo; Wen, Yangdong; Yu, Peng; Liu, Zhu; Wang, Yuechao; Li, Wen Jung

2016-12-01

Nanoscale correlation of structural information acquisition with specific-molecule identification provides new insight for studying rare subcellular events. To achieve this correlation, scanning electron microscopy has been combined with super-resolution fluorescent microscopy, despite its destructivity when acquiring biological structure information. Here we propose time-efficient non-invasive microsphere-based scanning superlens microscopy that enables the large-area observation of live-cell morphology or sub-membrane structures with sub-diffraction-limited resolution and is demonstrated by observing biological and non-biological objects. This microscopy operates in both non-invasive and contact modes with ~200 times the acquisition efficiency of atomic force microscopy, which is achieved by replacing the point of an atomic force microscope tip with an imaging area of microspheres and stitching the areas recorded during scanning, enabling sub-diffraction-limited resolution. Our method marks a possible path to non-invasive cell imaging and simultaneous tracking of specific molecules with nanoscale resolution, facilitating the study of subcellular events over a total cell period.

Learning to associate auditory and visual stimuli: behavioral and neural mechanisms.

PubMed

Altieri, Nicholas; Stevenson, Ryan A; Wallace, Mark T; Wenger, Michael J

2015-05-01

The ability to effectively combine sensory inputs across modalities is vital for acquiring a unified percept of events. For example, watching a hammer hit a nail while simultaneously identifying the sound as originating from the event requires the ability to identify spatio-temporal congruencies and statistical regularities. In this study, we applied a reaction time and hazard function measure known as capacity (e.g., Townsend and AshbyCognitive Theory 200-239, 1978) to quantify the extent to which observers learn paired associations between simple auditory and visual patterns in a model theoretic manner. As expected, results showed that learning was associated with an increase in accuracy, but more significantly, an increase in capacity. The aim of this study was to associate capacity measures of multisensory learning, with neural based measures, namely mean global field power (GFP). We observed a co-variation between an increase in capacity, and a decrease in GFP amplitude as learning occurred. This suggests that capacity constitutes a reliable behavioral index of efficient energy expenditure in the neural domain.

Decay of Mesoscale Flux Transfer Events During Quasi-Continuous Spatially Extended Reconnection at the Magentopause

NASA Technical Reports Server (NTRS)

Hasegawa, H.; Kitamura, N.; Saito, Y.; Nagai, T.; Shinohara, I.; Yokota, S.; Pollock, C. J.; Giles, B. L.; Dorelli, J. C.; Gershman, D. J.;

Delayed fission and multifragmentation in sub-keV C60 - Au(0 0 1) collisions via molecular dynamics simulations: Mass distributions and activated statistical decay

NASA Astrophysics Data System (ADS)

Bernstein, V.; Kolodney, E.

2017-10-01

We have recently observed, both experimentally and computationally, the phenomenon of postcollision multifragmentation in sub-keV surface collisions of a C60 projectile. Namely, delayed multiparticle breakup of a strongly impact deformed and vibrationally excited large cluster collider into several large fragments, after leaving the surface. Molecular dynamics simulations with extensive statistics revealed a nearly simultaneous event, within a sub-psec time window. Here we study, computationally, additional essential aspects of this new delayed collisional fragmentation which were not addressed before. Specifically, we study here the delayed (binary) fission channel for different impact energies both by calculating mass distributions over all fission events and by calculating and analyzing lifetime distributions of the scattered projectile. We observe an asymmetric fission resulting in a most probable fission channel and we find an activated exponential (statistical) decay. Finally, we also calculate and discuss the fragment mass distribution in (triple) multifragmentation over different time windows, in terms of most abundant fragments.

First simultaneous measurements of waves generated at the bow shock in the solar wind, the magnetosphere and on the ground

NASA Astrophysics Data System (ADS)

Clausen, L. B. N.; Yeoman, T. K.; Fear, R. C.; Behlke, R.; Lucek, E. A.; Engebretson, M. J.

2009-01-01

On 5 September 2002 the Geotail satellite observed the cone angle of the Interplanetary Magnetic Field (IMF) change to values below 30° during a 56 min interval between 18:14 and 19:10 UT. This triggered the generation of upstream waves at the bow shock, 13 RE downstream of the position of Geotail. Upstream generated waves were subsequently observed by Geotail between 18:30 and 18:48 UT, during times the IMF cone angle dropped below values of 10°. At 18:24 UT all four Cluster satellites simultaneously observed a sudden increase in wave power in all three magnetic field components, independent of their position in the dayside magnetosphere. We show that the 10 min delay between the change in IMF direction as observed by Geotail and the increase in wave power observed by Cluster is consistent with the propagation of the IMF change from the Geotail position to the bow shock and the propagation of the generated waves through the bow shock, magnetosheath and magnetosphere towards the position of the Cluster satellites. We go on to show that the wave power recorded by the Cluster satellites in the component containing the poloidal and compressional pulsations was broadband and unstructured; the power in the component containing toroidal oscillations was structured and shows the existence of multi-harmonic Alfvénic continuum waves on field lines. Model predictions of these frequencies fit well with the observations. An increase in wave power associated with the change in IMF direction was also registered by ground based magnetometers which were magnetically conjunct with the Cluster satellites during the event. To the best of our knowledge we present the first simultaneous observations of waves created by backstreaming ions at the bow shock in the solar wind, the dayside magnetosphere and on the ground.

Acceleration mechanisms for energetic particles in the earth's magnetosphere

NASA Technical Reports Server (NTRS)

Schiferl, S.; Fan, C. Y.; Hsieh, K. C.; Erickson, K. N.; Gloeckler, G.

1982-01-01

By analyzing data on energetic particle fluxes measured simultaneously with detector systems on several earth satellites, signatures of different acceleration mechanisms for these particles were searched for. One of the samples is an event observed on ATS-6 and IMP-7. IMP-7 was in the dusk quarter at 38 earth radii while ATS-6 was located at local midnight at a distance of 6.6 earth radii. Although the flux variations as observed on the two spacecraft both showed 1.5 min periodicity, there was a 40-second time lag with IMP-7 behind. The results indicate that the particles are accelerated by magnetic field line annihilation, with the x-point located at about 10 earth radii.

Dynamic effects of restoring footpoint symmetry on closed magnetic field lines

NASA Astrophysics Data System (ADS)

Reistad, J. P.; Østgaard, N.; Tenfjord, P.; Laundal, K. M.; Snekvik, K.; Haaland, S.; Milan, S. E.; Oksavik, K.; Frey, H. U.; Grocott, A.

2016-05-01

Here we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from conjugate auroral imaging. This is interpreted as evidence of closed field lines having very asymmetric footpoints associated with the persistent positive y component of the interplanetary magnetic field before and during the event. At the same time, the Super Dual Auroral Radar Network observes the ionospheric nightside convection throat region in both hemispheres. The radar data indicate faster convection toward the dayside in the dusk cell in the Southern Hemisphere compared to its conjugate region. We interpret this as a signature of a process acting to restore symmetry of the displaced closed magnetic field lines resulting in flux tubes moving faster along the banana cell than the conjugate orange cell. The event is analyzed with emphasis on Birkeland currents (BC) associated with this restoring process, as recently described by Tenfjord et al. (2015). Using data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during the same conditions as the presented event, the large-scale BC pattern associated with the event is presented. It shows the expected influence of the process of restoring symmetry on BCs. We therefore suggest that these observations should be recognized as being a result of the dynamic effects of restoring footpoint symmetry on closed field lines in the nightside.

Subauroral polarization stream on the outer boundary of the ring current during an energetic ion injection event

NASA Astrophysics Data System (ADS)

Yuan, Zhigang; Qiao, Zheng; Li, Haimeng; Huang, Shiyong; Wang, Dedong; Yu, Xiongdong; Yu, Tao

2017-04-01

Subauroral polarization stream (SAPS) electric field can play an important role in the coupling between the inner magnetosphere and ionosphere; however, the production mechanism of SAPS has not been yet solved. During an energetic ion injection event on 26 March 2004, at latitudes lower than the equatorward boundaries of precipitating plasma sheet electrons and ions, the Defense Meteorological Satellite Program (DMSP) F13 satellite simultaneously observed a strong SAPS with the peak velocity of 1294 m/s and downward flowing field-aligned currents (FACs). Conjugate observations of DMSP F13 and NOAA 15 satellites have shown that FACs flowing into the ionosphere just lie in the outer boundary of the ring current (RC). The downward flowing FACs were observed in a region of positive latitudinal gradients of the ion energy density, implying that the downward flowing FACs are more likely linked to the azimuthal gradient than the radial gradient of the RC ion pressure. Our result demonstrates that RC ion pressure gradients on the outer boundary of the RC in the evening sector during energetic ion injection events can lead to downward flowing FACs so as to cause strong SAPS in condition of low ionospheric conductivities.