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Sample records for chorus giganteus lesson

  1. New Chorus Diffusion Matrix

    NASA Astrophysics Data System (ADS)

    Horne, Richard B.; Kersten, Tobias; Glauert, Sarah A.; Meredith, Nigel P.; Boscher, Daniel; Sicard, Angelica; Maget, Vincent

    2013-04-01

    Whistler mode chorus waves play a major role in the loss and acceleration of electrons in the Earth's radiation belts. While high time resolution satellite data show that these waves are highly structured in frequency and time, at present their effects on the electron distribution can only be assessed on a global scale by using quasi-linear diffusion theory. Here we present new quasi-linear diffusion coefficients for upper and lower band chorus waves for use in global radiation belt models. Using data from DE 1 CRRES, Cluster 1, Double Star TC1 and THEMIS, we have constructed a database of wave properties and used this to construct new diffusion coefficients for L* = 1.5 to 10 in steps of 0.5, 10 latitude bins between 0o and 60o ,8 bins in MLT and 5 levels of geomagnetic activity as measured by Kp. We find that the peak frequency of lower band chorus is close to 0.2 fce, which is lower than that used in previous models. The combined upper and lower band chorus diffusion shows structure that should result in an energy dependent pitch angle anisotropy, particularly between 1 keV and 100 keV. The diffusion rates suggest that wave-particle interactions should still be very important outside geostationary orbit, out to at least L* = 8. We find significant energy diffusion near 1 keV near the loss cone, consistent with wave growth. By including the new chorus diffusion matrix into the BAS radiation belt (BRB) model we compare the effects on the evolution of the radiation belts against previous models.

  2. The Function of the Tragic Greek Chorus.

    ERIC Educational Resources Information Center

    Weiner, Albert

    1980-01-01

    Discusses the function of the chorus in Greek tragedy and highlights interpretations of Aristotle's statements on the chorus. Concludes that the chorus' role was that of alienating the audience and was basically theatrical, not dramatic. (JMF)

  3. Indopithecus giganteus distinct from Sivapithecus indicus

    USGS Publications Warehouse

    Madden, C.T.; Lewis, G.E.

    1980-01-01

    The very large Eurasian Miocene ape Indopithecus giganteus is distinct from contemporanious Sivapithecus (non-Dryopithecus)indicus. The probabilities that length and width for the only specimen of I. giganteus could be sampled from populations similar or identical to those of S. indicus are less than six chances in 100,000 for both parameters. ?? 1980 Japan Monkey Centre.

  4. Magnetospheric chorus - Amplitude and growth rate

    NASA Technical Reports Server (NTRS)

    Burtis, W. J.; Helliwell, R. A.

    1975-01-01

    A new study of the amplitude of magnetospheric chorus with 1966-1967 data from the Stanford University/Stanford Research Institute VLF receivers on Ogo 1 and Ogo 3 has confirmed the band-limited character of magnetospheric chorus in general and the double-banding of near-equatorial chorus. Chorus amplitude tended to be inversely correlated with frequency, implying lower intensities at lower L values. Individual chorus emissions often showed a characteristic amplitude variation, with rise times of 10 to 300 ms, a short duration at peak amplitude, and decay times of 100 to 3000 msec. Growth was often approximately exponential, with rates from 200 to nearly 2000 dB/sec. Rate of change of frequency was found in many cases to be independent of emission amplitude, in agreement with the cyclotron feedback theory of chorus (Helliwell, 1967, 1970).

  5. Miscanthus x giganteus xylooligosaccharides: Purification andfermentation

    USDA-ARS?s Scientific Manuscript database

    A procedure was developed to recover xylooligosaccharides (XOS) from Miscanthus x giganteus (MxG) hydrolyzates. MxG hydrolyzates were prepared using autohydrolysis, and XOS rich fractions were acquired using activated carbon adsorption and stepwise ethanol elution. The combined XOS fractions were pu...

  6. Analysis of chorus emissions at Jupiter

    NASA Astrophysics Data System (ADS)

    Coroniti, F. V.; Scarf, F. L.; Kennel, C. F.; Kurth, W. S.

    1984-06-01

    The emissions in the chorus frequency band which were detected on the Voyager 1 inbound pass between about ten and six Jupiter radii are surveyed. An overview of the plasma and wave observations during the inbound pass is presented and the spatial regions in which chorus band signals were observed are discussed. A series of wide-band frequency-time frames which characterize the onset of two observed intervals of chorus band activity is displayed. A detailed examination is made of the spectra for rising chorus which sweeps upward in frequency from 0.2 to 0.5 times the electron cyclotron frequency f(c). Two temporally successive wide-band frames in which several types of chorus band emissions were observed are discussed. The spatial morphology of chorus is discussed in terms of the electron energies which resonate with whistler mode waves. A recent theory of chorus generation is reviewed along with theories and a model explaining the narrow-band emissions above f(c)/2.

  7. Relationship between Chorus and Plasmaspheric Hiss Waves

    NASA Astrophysics Data System (ADS)

    Bortnik, J.; Chen, L.; Li, W.; Thorne, R. M.; Nishimura, Y.; Angelopoulos, V.; Kletzing, C. A.

    2016-02-01

    This chapter focuses on the origin of the plasmaspheric hiss (PH) emission, and in particular, considers whether chorus could be the embryonic source of PH. It describes the ray-tracing model used to study chorus wave propagation. The chapter mainly focuses on more recent observations that still raise puzzling questions regarding the origin of PH. It then shows that PH has a lower frequency boundary, and that, at least in some instances, chorus could not be the source of the PH power and that it would necessarily need to be excited locally. The chapter also shows a coincident observation between THEMIS-E and one of the newly launched Van Allen Probes (RB-B) that showed simultaneous chorus and hiss emissions. These emissions were very well correlated but occurred at much higher L-shells than predicted by our ray-tracing model.

  8. Breeding chorus indices are weakly related to estimated abundance of boreal chorus frogs

    Treesearch

    Paul Stephen Corn; Erin Muths; Amanda M. Kissel; Rick D. Scherer

    2011-01-01

    Call surveys used to monitor breeding choruses of anuran amphibians generate index values that are frequently used to represent the number of male frogs present, but few studies have quantified this relationship. We compared abundance of male Boreal Chorus Frogs (Pseudacris maculata), estimated using capture-recapture methods in two populations in Colorado, to call...

  9. Ducted propagation of chorus waves: Cluster observations

    NASA Astrophysics Data System (ADS)

    Yearby, K. H.; Balikhin, M. A.; Khotyaintsev, Yu. V.; Walker, S. N.; Krasnoselskikh, V. V.; Alleyne, H. St. C. K.; Agapitov, O.

    2011-09-01

    Ducted propagation of whistler waves in the terrestrial magnetosphere-ionosphere system was discussed and studied long before the first in-situ spacecraft measurements. While a number of implicit examples of the existence of ducted propagation have been found, direct observation of ducts has been hampered by the low sampling rates of measurements of the plasma density. The present paper is based on Cluster observations of chorus waves. The ability to use measurements of the spacecraft potential as a proxy for high time resolution electron density measurements is exploited to identify a number of cases when increased chorus wave power, observed within the radiation belts, is observed simultaneously with density enchantments. It is argued that the observation of ducted propagation of chorus implies modification of numerical models for plasma-wave interactions within the radiation belts.

  10. Saturn Chorus as a Function of Latitude

    NASA Astrophysics Data System (ADS)

    Menietti, J. D.; Hospodarsky, G. B.; Gurnett, D. A.; Shprits, Y.

    2013-12-01

    Not only the dust but also the spatial scale of Saturn, including the background magnetic field inhomogeneity, make the study of whistler mode plasma wave emissions at Saturn quite different from Earth. The significant decrease in chorus intensity nearest the Saturn magnetic equator along a nearly constant L shell has already been reported. In the current study we analyze all known examples of these data and report the collective functional dependence of chorus intensity and wave normal angle, as well as density and magnetic inhomogeneity versus latitude. These values are important in the modeling of pitch angle scattering and possible electron acceleration at Saturn.

  11. Bursty Precipitation Driven by Chorus Waves

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Telnikhin, A. A.; Kronberg, T. K.

    2011-01-01

    The electron precipitation bursts have been shown to be a major sink for the radiation belt relativistic electrons. As underlying mechanism of such bursts, we propose particle scattering into the loss cone due to nonlinear resonance interaction between electrons and chorus. Stochastic heating due to the coupling leads to diffusion in pitch angle, and the rate of diffusion would be sufficient to account for the emptying of the Earth's radiation belt over the time of the main phase of geomagnetic storms. The results obtained in the present paper account for a strong energy dependence in the electron precipitation event and the correlation between the energization and loss processes on macroscopic timescales, which is primarily attributed to the cooperative effects of the coupling. This mechanism of chorus scattering should produce pitch angle distributions that are energy-dependent and butterfly-shaped. The calculated timescales and the total energy input to the atmosphere from precipitating relativistic electrons are in reasonable agreement with experimental data.

  12. A model for chorus associated electrostatic bursts

    NASA Technical Reports Server (NTRS)

    Grabbe, C. L.

    1984-01-01

    The linear theory of the generation of electrostatic bursts of noise by electrons trapped in chorus wave packets is developed for a finite temperature electron beam and a Maxwellian elecron and ion background. The growth rates determined qualitatively in good agreement with those obtained by previous authors from a more idealized model. Two connected instability mechanisms seem to be occurring: a beam plasma (electron-ion two-stream) instability commonly associated with intensification of the chorus power levels, and a transitional or borderline resistive medium instability commonly associated with chorus hooks. The physical reasons for the two mechanisms is discussed. In the second case electron beams are difficult to identify in the particle data. An expression is obtained for the maximum growth rate in terms of the ratios of the beam and electron thermal velocities to the beam velocity, and of the beam density to plasma density. It is anticipated that this may allow the observed peak in the electrostatic noise spectrum to be used as a diagnostic for the beam characteristics. Previously announced in STAR as N84-12832

  13. Breeding chorus indices are weakly related to estimated abundance of boreal chorus frogs

    USGS Publications Warehouse

    Corn, P.S.; Muths, E.; Kissel, A.M.; Scherer, R. D.

    2011-01-01

    Call surveys used to monitor breeding choruses of anuran amphibians generate index values that are frequently used to represent the number of male frogs present, but few studies have quantified this relationship. We compared abundance of male Boreal Chorus Frogs (Pseudacris maculata), estimated using capture–recapture methods in two populations in Colorado, to call index values derived from automated recordings. Single index values, such as might result from large monitoring efforts, were unrelated to population size. A synthetic call saturation index (CSI), the daily proportion of the maximum possible sum of index values derived from multiple recordings, was greater in larger populations, but the relationship was not highly predictive.

  14. Purification and characterization of xylooligosaccharides (XOS) from Miscanthus x giganteus

    USDA-ARS?s Scientific Manuscript database

    Our previous investigation showed that xylooligosaccharides (XOS) could be produced effectively from Miscanthus x giganteus (MxG). Using autohydrolysis, an XOS yield of to 13.5% (w/w) of initial biomass and xylan yield of 69.2% (w/w) was observed. In this study, we investigated the purification of X...

  15. Henipavirus infection in fruit bats (Pteropus giganteus), India.

    PubMed

    Epstein, Jonathan H; Prakash, Vibhu; Smith, Craig S; Daszak, Peter; McLaughlin, Amanda B; Meehan, Greer; Field, Hume E; Cunningham, Andrew A

    2008-08-01

    We tested 41 bats for antibodies against Nipah and Hendra viruses to determine whether henipaviruses circulate in pteropid fruit bats (Pteropus giganteus) in northern India. Twenty bats were seropositive for Nipah virus, which suggests circulation in this species, thereby extending the known distribution of henipaviruses in Asia westward by >1,000 km.

  16. Cluster Observations of Whistler Mode Ducts and Banded Chorus

    NASA Astrophysics Data System (ADS)

    Haque, N.; Inan, U. S.; Bell, T. F.

    2011-12-01

    Bell et al., [2009] proposed that the source region for banded chorus consists of whistler mode ducts of depleted electron density (Ne) for upper band (UB) chorus for all wave normal angles (θ) and ducts of either enhanced or depleted Ne for lower band (LB) chorus, for small θ and θ near or greater than the Gendrin angle (θG), respectively. We provide support for this model using new high resolution (17 km) Ne observations from the Cluster WHISPER and EFW instruments. Data is examined from January 20, 2004, when strong banded chorus was observed over 3000 km of the Cluster 2 orbit, ending at the magnetic equator. Previous analysis of LB chorus on this day showed θ>θG [Santolík et al., 2009; Chum et al., 2009]. Using the Ne data, we show that the LB chorus is generated within depletion ducts in the source region and that the half-width of these ducts (˜70 km) is comparable to the transverse scale (˜100 km) of the chorus source region. Making use of the fact that the group velocity of the LB chorus waves has a significant cross-L component, we show the source region extends over 500 km near the magnetic equator.

  17. Survey of whistler mode chorus intensity at Jupiter

    NASA Astrophysics Data System (ADS)

    Menietti, J. D.; Groene, J. B.; Averkamp, T. F.; Horne, R. B.; Woodfield, E. E.; Shprits, Y. Y.; Soria-Santacruz Pich, M.; Gurnett, D. A.

    2016-10-01

    Whistler mode chorus emission is important in the acceleration of electrons and filling of the radiation belts at Jupiter. In this work chorus magnetic intensity levels (frequency-integrated spectral density, PB) at Jupiter are comprehensively binned and parameterized. The frequency range of chorus under study extends from the lower hybrid frequency, flh, to fceq/2 and fceq/2 < f < 0.8 fceq, where fceq is the cyclotron frequency mapped to the magnetic equator. The goal is to obtain a quantized distribution of magnetic intensity for use in stochastic modeling efforts. Parametric fits of magnetic plasma wave intensity are obtained, including PB versus frequency, latitude, and L shell. The results indicate that Jupiter chorus occurrence probability and intensity are higher than those at Saturn, reaching values observed at Earth. Jovian chorus is observed over most local times, confined primarily to the range 8 < L < 15, outside the high densities of the Io torus. The largest intensity levels are seen on the dayside; however, the sampling of chorus on the nightside is much less than on the dayside. Peak intensities occur near the equator with a weak dependence on magnetic latitude, λ. We conclude that Jovian chorus average intensity levels are approximately an order of magnitude lower than those at Earth. In more isolated regions the intensities are comparable to those observed at Earth. The spatial range of the chorus emissions extends beyond that assumed in previous Jovian global diffusive models of wave-particle electron acceleration.

  18. Simultaneous observation of chorus and hiss near the plasmapause

    NASA Astrophysics Data System (ADS)

    Delport, B.; Collier, A. B.; Lichtenberger, J.; Rodger, C. J.; Parrot, M.; Clilverd, M. A.; Friedel, R. H. W.

    2012-12-01

    On 4 August 2010 a moderate geomagnetic storm occurred with minimum Dst of -65 nT and maximum Kp of 7-. Shortly after the onset of this storm, VLF chorus was observed at Marion Island (L= 2.6). Over time the spectral structure of the chorus transformed into a hiss band spanning the same frequency range. The observation of overlapping chorus and hiss suggests that Marion Island was close to the plasmapause at the time of this event, and provides ground-based observational confirmation of the generation mechanism of plasmaspheric hiss from chorus waves outside of the plasmasphere. Chorus observations at Marion Island were not common during this period of the solar cycle and so this event was investigated in detail. The geomagnetic conditions are discussed and geosynchronous particle data and broadband data from two other stations are presented. Empirical models are employed to predict the location of the plasmapause, and its location is inferred from a knee whistler recorded at Dunedin, New Zealand. These show that Marion Island is in the vicinity of the plasmapause during the event. The event is also compared to chorus observed at similarL after the Halloween storms of 2003. The rarity of the chorus observation is quantified using DEMETER VLF data. The DEMETER data, along with the various ground based VLF measurements, allows us to infer temporal and spatial variations in the chorus source region.

  19. Generation of extremely low frequency chorus in Van Allen radiation belts: ELF CHORUS GENERATION

    DOE PAGES

    Xiao, Fuliang; Liu, Si; Tao, Xin; ...

    2017-01-01

    Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasmasheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency relativistic effects should be considered in the formula for whistler-mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm andmore » firstly demonstrate, using a fully relativistic simulation, that electrons with the high energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 fce. The simulated wave growth displays a very similar pattern to the observations. Finally, the current results can be applied to Jupiter, Saturn and other magnetized planets.« less

  20. Generation of extremely low frequency chorus in Van Allen radiation belts: ELF CHORUS GENERATION

    SciTech Connect

    Xiao, Fuliang; Liu, Si; Tao, Xin; Su, Zhenpeng; Zhou, Qinghua; Yang, Chang; He, Zhaoguo; He, Yihua; Gao, Zhonglei; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.

    2017-01-01

    Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasmasheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency relativistic effects should be considered in the formula for whistler-mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm and firstly demonstrate, using a fully relativistic simulation, that electrons with the high energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 fce. The simulated wave growth displays a very similar pattern to the observations. Finally, the current results can be applied to Jupiter, Saturn and other magnetized planets.

  1. Effects of Hurricane Charley on fish chorusing

    PubMed Central

    Locascio, James V; Mann, David A

    2005-01-01

    Hurricane Charley, a category 4 hurricane, passed through Charlotte Harbor, Florida, directly over an autonomous underwater acoustic datalogger used to record sound production by fishes associated with courtship and spawning. Acoustic recordings made on 9 days prior to the storm, during and 3 days after the storm provided unprecedented documentation of the hurricane's passage and its effect on fishes' calling behaviour. The hurricane did not inhibit nightly chorusing events of spawning fish. Sound levels produced by spawning fish on the night of and 3 days after the hurricane were higher and lasted longer than any of the 9 days recorded prior to the hurricane. PMID:17148207

  2. Animal choruses emerge from receiver psychology

    PubMed Central

    Greenfield, Michael D.; Esquer-Garrigos, Yareli; Streiff, Réjane; Party, Virginie

    2016-01-01

    Synchrony and alternation in large animal choruses are often viewed as adaptations by which cooperating males increase their attractiveness to females or evade predators. Alternatively, these seemingly composed productions may simply emerge by default from the receiver psychology of mate choice. This second, emergent property hypothesis has been inferred from findings that females in various acoustic species ignore male calls that follow a neighbor’s by a brief interval, that males often adjust the timing of their call rhythm and reduce the incidence of ineffective, following calls, and from simulations modeling the collective outcome of male adjustments. However, the purported connection between male song timing and female preference has never been tested experimentally, and the emergent property hypothesis has remained speculative. Studying a distinctive katydid species genetically structured as isolated populations, we conducted a comparative phylogenetic analysis of the correlation between male call timing and female preference. We report that across 17 sampled populations male adjustments match the interval over which females prefer leading calls; moreover, this correlation holds after correction for phylogenetic signal. Our study is the first demonstration that male adjustments coevolved with female preferences and thereby confirms the critical link in the emergent property model of chorus evolution. PMID:27670673

  3. Does ELF chorus show evidence of power line stimulation

    NASA Technical Reports Server (NTRS)

    Tsurutani, B. T.; Smith, E. J.; Church, S. R.; Thorne, R. M.; Holzer, R. E.

    1979-01-01

    A study to determine the effect of power line radiation on the stimulation of the ELF chorus detected on OGO-5 is presented. Chorus shows a maxima over the Eastern USSR, Greenland, and Central Siberia and minima over central and Eastern Canada, a distribution different than the OGO-3. This discrepancy is explained as due to data oversampling in the previous study; the OGO-5 data were reanalyzed with the oversampling removed, showing that none of the longitudinal maxima or minima are statistically significant. It is concluded that there is no significant correlation between longitude and chorus occurrence which implies that there is little or no evidence of power line harmonic radiation effects on chorus triggering.

  4. Laboratory simulation of magnetospheric chorus wave generation

    NASA Astrophysics Data System (ADS)

    Van Compernolle, B.; An, X.; Bortnik, J.; Thorne, R. M.; Pribyl, P.; Gekelman, W.

    2017-01-01

    Whistler mode chorus emissions with a characteristic frequency chirp are important magnetospheric waves, responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. A laboratory experiment (Van Compernolle et al 2015 Phys. Rev. Lett. 114 245002, An et al 2016 Geophys. Res. Lett.) in the large plasma device at UCLA was designed to closely mimic the scaled plasma parameters observed in the inner magnetosphere, and shed light on the excitation of discrete frequency whistler waves. It was observed that a rich variety of whistler wave emissions is excited by a gyrating electron beam. The properties of the whistler emissions depend strongly on plasma density, beam density and magnetic field profiles.

  5. Development and feeding of fall armyworm, on Miscanthus x giganteus and switchgrass

    USDA-ARS?s Scientific Manuscript database

    Observations of fall armyworm [Spodoptera frugiperda (J.E. Smith)] larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development and feeding preferences on leaf tissue from M. x giganteus and switchgrass (Panicum ...

  6. Hepatoprotective Effects of Panus giganteus (Berk.) Corner against Thioacetamide- (TAA-) Induced Liver Injury in Rats

    PubMed Central

    Wong, Wei-Lun; Abdulla, Mahmood Ameen; Chua, Kek-Heng; Kuppusamy, Umah Rani; Tan, Yee-Shin; Sabaratnam, Vikineswary

    2012-01-01

    Panus giganteus, a culinary and medicinal mushroom consumed by selected indigenous communities in Malaysia, is currently being considered for large scale cultivation. This study was undertaken to investigate the hepatoprotective effects of P. giganteus against thioacetamide- (TAA-) induced liver injury in Sprague-Dawley rats. The rats were injected intraperitoneally with TAA thrice weekly and were orally administered freeze-dried fruiting bodies of P. giganteus (0.5 or 1 g/kg) daily for two months, while control rats were given vehicle or P. giganteus only. After 60 days, rats administered with P. giganteus showed lower liver body weight ratio, restored levels of serum liver biomarkers and oxidative stress parameters comparable to treatment with the standard drug silymarin. Gross necropsy and histopathological examination further confirmed the hepatoprotective effects of P. giganteus. This is the first report on hepatoprotective effects of P. giganteus. The present study showed that P. giganteus was able to prevent or reduce the severity of TAA-induced liver injury. PMID:22649470

  7. Global model of whistler mode chorus from multiple satellite observations

    NASA Astrophysics Data System (ADS)

    Meredith, Nigel; Horne, Richard; Sicard-Piet, Angelica; Boscher, Daniel; Yearby, Keith; Li, Wen; Thorne, Richard

    2013-04-01

    Gyroresonant wave particle interactions with whistler mode chorus play a fundamental role in the dynamics of the Earth's radiation belts and inner magnetosphere, affecting both the acceleration and loss of radiation belt electrons. Knowledge of the variability of chorus wave power as a function of both spatial location and geomagnetic activity, required for the computation of pitch angle and energy diffusion rates, is thus a critical input for global radiation belt models. Here we present a global model of lower band (0.1fce < f < 0.5fce) and upper band (0.5fce < f < fce) chorus, where fce is the local electron gyrofrequency, using plasma wave data from DE1, CRRES, Cluster 1, Double Star TC1 and THEMIS, extending the coverage and improving the statistics of existing models. The chorus emissions extend from the plasmapause out to L* = 10 and are found to be largely substorm dependent with the largest intensities being seen during active conditions. Equatorial lower band chorus is strongest during active conditions with peak intensities of the order 2000 pT2 in the region 4 < L* < 9 between 2300 and 1200 MLT. Equatorial upper band chorus is both weaker and less extensive with peak intensities of the order a few hundred pT2 during active conditions between 2300 and 1100 MLT from L* = 3 to L* = 7. Moving away from the equator mid-latitude chorus is strongest in the lower band during active conditions with peak intensities of the order 2000 pT2 in the region 4 < L* < 9 but is restricted to the dayside between 0700 and 1400 MLT. The results suggest that including wave particle interactions beyond geostationary orbit could be very important for global radiation belt models.

  8. Avian cholera in Southern Great Petrel (Macronectes giganteus) from Antarctica

    USGS Publications Warehouse

    Leotta, G.A.; Rivas, M.; Chinen, I.; Vigo, G.B.; Moredo, F.A.; Coria, N.; Wolcott, M.J.

    2003-01-01

    A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica.

  9. Source extension of chorus waves in the equatorial plane

    NASA Astrophysics Data System (ADS)

    Hayosh, M.; Santolik, O.; Parrot, M.

    2009-04-01

    We use measurements of the Cluster spacecraft and a ray tracing simulation to estimate the location and size of the global source of whistler-mode chorus emissions. In this study we use the data provided simultaneously by the STAFF-SA instruments on the four Cluster spacecraft on 19 August, 2003. To determine the direction of propagation of chorus we calculate Poynting vector whereas a ray-tracing method is used to estimate the chorus source extension. For the first time this analysis has been made along whole particular Cluster orbit in both hemispheres. Our study shows that minimum size of the global chorus source region in the equatorial plane is between 1-3 Earth's radii. The resulting location of the chorus source region is at radial distances between 3 and 8 Earth radii. This result is in agreement with previous analysis of Cluster data by Parrot et al., 2003, 2004 and with the study of Santolik et al., 2005 who analyzed data from the Double Star TC-1 spacecraft.

  10. Triggering process of whistler mode chorus emissions in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Omura, Yoshiharu; Nunn, David

    2011-05-01

    Chorus emissions are triggered from the linear cyclotron instability driven by the temperature anisotropy of energetic electrons (10-100 keV) in the magnetosphere. Chorus emissions grow as an absolute nonlinear instability near the magnetic equator because of the presence of an electromagnetic electron hole in velocity space. The transition process from the linear wave growth at a constant frequency to the nonlinear wave growth with a rising tone frequency is due to formation of a resonant current -JB antiparallel to the wave magnetic field. The rising-tone frequency introduces a phase shift to the electron hole at the equator and results in a resonant current component antiparallel to the wave electric field -JE, which causes the nonlinear wave growth. To confirm this triggering mechanism, we perform Vlasov hybrid simulations with JB and without JB. The run without JB does not reproduce chorus emissions, while the run with JB does successfully reproduce chorus emissions. The nonlinear frequency shift ω1 due to JB plays a critical role in the triggering process. The nonlinear transition time TN for the frequency shift is found to be of the same order as the nonlinear trapping period, which is confirmed by simulations and observation. The established frequency sweep rate is ω1/TN, which gives an optimum wave amplitude of chorus emissions.

  11. The Development of Chorus Motivation Scale (CMS) for Prospective Music Teacher

    ERIC Educational Resources Information Center

    Ozgul, Ilhan; Yigit, Nalan

    2017-01-01

    The purpose of this study was to develop a Chorus Motivation Scale (CMS) that is tested in terms of reliability and construct validity by determining the student perceptions of effective motivation strategies in Chorus training in Turkish Music Teacher Training Model. In order to develop a Chorus Motivation Scale, Questionnaire-Effective…

  12. Masticatory muscles of the great-gray kangaroo (Macropus giganteus).

    PubMed

    Tomo, Soichiro; Tomo, Ikuko; Townsend, Grant C; Hirata, Kazuaki

    2007-04-01

    The great-gray kangaroo (Macropus giganteus) belongs to the Diprotodontia suborder (herbivorous marsupials of Australia) of the order of marsupials. We dissected the masticatory muscles in the great-gray kangaroo and classified them based on their innervation. Three (two male and one female) adult great-gray kangaroos (M. giganteus), fixed with 10% formalin, were examined. The masseter muscle of the great-gray kangaroo was classified into four layers (superficial layers 1, 2, 3, and a deep layer), all innervated by masseteric nerves. Layer 1 of the masseter muscle was well developed and the deep layer inserted into the masseteric canal. The zygomaticomandibular muscle, which belongs to both the masseter and temporalis muscles, was innervated by both the masseteric nerve and posterior deep temporal nerve, and the temporalis muscle was innervated by the anterior and posterior deep temporal nerves. The medial pterygoid muscle, which was innervated by the medial pterygoid nerve, was divided into superficial and deep portions. The lateral pterygoid muscle was divided into superior and inferior heads by the buccal nerve. We propose that the relationship of the masticatory muscles in the kangaroo has evolved by passive anterior invasion of the deep layer of the masseter by the medial pterygoid muscle via the masseteric canal, associated with the development of an anteroposterior mode of mastication.

  13. The Origin of Narrow Band Cyclotron Wave Emissions Called Chorus

    NASA Astrophysics Data System (ADS)

    Skoug, Ruth Marie

    1995-01-01

    On May 6, 1993, a sounding rocket experiment designed to study microburst electron precipitation was launched from Poker Flat, Alaska, into a morningside auroral event. This was the first sounding rocket to simultaneously detect microburst electrons and associated very low frequency (VLF) waves. Both microbursts and narrow band VLF chorus (risers) were observed throughout the flight. Waves and electron bursts were observed in association with each other, but no one-to-one correlations were seen between the two phenomena. The association between waves and particles suggests that both phenomena may be produced by a wave -particle interaction. This dissertation discusses the design of the VLF wave antenna, a magnetic search coil, and the analysis of data from this instrument. The data are compared to chorus production theories to determine the source location and mechanism of the observed waves. In this work, the observed chorus emissions are interpreted in terms of a cyclotron resonance interaction. This is the first comprehensive test of the cyclotron resonance theory applied to chorus associated with microburst precipitation. The frequency range of the risers and the observed electron energy range agree with those required to satisfy the cyclotron resonance condition. Using a criterion derived from the conservation of energy during an interaction, it is determined that a cold plasma cyclotron resonance interaction could have produced only the lower frequency portions of the observed chorus risers. We present an extension of the cyclotron resonance theory which uses a warm plasma model of the wave-particle interaction. This model assumes a two-component plasma, with an isotropic cold component and a bi-Maxwellian warm component. The addition of the warm component produces sufficient changes in the wave dispersion relation that the interaction can produce the highest frequencies observed in our data set. As predicted by theory, an anisotropic plasma is required to

  14. Chorusing, synchrony, and the evolutionary functions of rhythm

    PubMed Central

    Ravignani, Andrea; Bowling, Daniel L.; Fitch, W. Tecumseh

    2014-01-01

    A central goal of biomusicology is to understand the biological basis of human musicality. One approach to this problem has been to compare core components of human musicality (relative pitch perception, entrainment, etc.) with similar capacities in other animal species. Here we extend and clarify this comparative approach with respect to rhythm. First, whereas most comparisons between human music and animal acoustic behavior have focused on spectral properties (melody and harmony), we argue for the central importance of temporal properties, and propose that this domain is ripe for further comparative research. Second, whereas most rhythm research in non-human animals has examined animal timing in isolation, we consider how chorusing dynamics can shape individual timing, as in human music and dance, arguing that group behavior is key to understanding the adaptive functions of rhythm. To illustrate the interdependence between individual and chorusing dynamics, we present a computational model of chorusing agents relating individual call timing with synchronous group behavior. Third, we distinguish and clarify mechanistic and functional explanations of rhythmic phenomena, often conflated in the literature, arguing that this distinction is key for understanding the evolution of musicality. Fourth, we expand biomusicological discussions beyond the species typically considered, providing an overview of chorusing and rhythmic behavior across a broad range of taxa (orthopterans, fireflies, frogs, birds, and primates). Finally, we propose an “Evolving Signal Timing” hypothesis, suggesting that similarities between timing abilities in biological species will be based on comparable chorusing behaviors. We conclude that the comparative study of chorusing species can provide important insights into the adaptive function(s) of rhythmic behavior in our “proto-musical” primate ancestors, and thus inform our understanding of the biology and evolution of rhythm in human

  15. Competition and cooperation in a synchronous bushcricket chorus

    PubMed Central

    Hartbauer, M.; Haitzinger, L.; Kainz, M.; Römer, H.

    2014-01-01

    Synchronous signalling within choruses of the same species either emerges from cooperation or competition. In our study on the katydid Mecopoda elongata, we aim to identify mechanisms driving evolution towards synchrony. The increase of signal amplitude owing to synchronous signalling and the preservation of a conspecific signal period may represent cooperative mechanisms, whereas chorus synchrony may also result from the preference of females for leading signals and the resulting competition for the leader role. We recorded the timing of signals and the resulting communal signal amplitudes in small choruses and performed female choice experiments to identify such mechanisms. Males frequently timed their signals either as leader or follower with an average time lag of about 70 ms. Females selected males in such choruses on the basis of signal order and signal duration. Two-choice experiments revealed a time lag of only 70 ms to bias mate choice in favour of the leader. Furthermore, a song model with a conspecific signal period of 2 s was more attractive than a song model with an irregular or longer and shorter than average signal period. Owing to a high degree of overlap and plasticity of signals produced in ‘four male choruses’, peak and root mean square amplitudes increased by about 7 dB relative to lone singers. Modelling active space of synchronous males and solo singing males revealed a strongly increased broadcast area of synchronous signallers, but a slightly reduced per capita mating possibility compared with lone singers. These results suggest a strong leader preference of females as the ultimate causation of inter-male competition for timing signals as leader. The emerging synchrony increases the amplitude of signals produced in a chorus and has the potential to compensate a reduction of mating advantage in a chorus. We discuss a possible fitness benefit of males gained through a beacon effect and the possibility that signalling as follower is

  16. The hydrometeorological sustainability of Miscanthus x giganteus as a biofuel crop in the US Midwest

    NASA Astrophysics Data System (ADS)

    Roy, Gavin R.

    Miscanthus x giganteus (M. x giganteus ) is a dense, 3-5 m tall, productive perennial grass that has been suggested to replace corn as the principal source of biofuel for the US transportation industry. However, cultivating a regime of this water-intensive rhizomatous crop across the US Midwest may not be agronomically realistic if it is unable to survive years of low precipitation or extreme cold wintertime soil temperatures, both of which have previously killed experimental crops. The goal of this research was to use a third-generation land surface model (LSM) to provide a new assessment of the hypothetical biogeophysical sustainability of a regime of M. x giganteus across the US Midwest given that, for the first time, a robust and near-complete dataset over a large area of mature M. x giganteus was available for model validation. Modifications to the local hydrology and microclimate would necessarily occur in areas where M. x giganteus is adapted, but a switch to this biofuel crop can only occur where its intense growing season water usage (up to 600 mm) and wintertime soil temperature requirements (no less than -6° C) are feasibly sustainable without irrigation. The first step was to interpret the observed turbulent and ecosystem flux behavior over an extant area of mature M. x giganteus and replicate this behavior within the SiB3 third-generation LSM (Simple Biosphere Model, version 3). A new vegetation parameterization was developed in SiB3 using several previous empirical studies of M. x giganteus as a foundation. The simulation results were validated against a new, robust series of turbulent and ecosystem flux data taken over a four-hectare experimental crop of M. x giganteus in Champaign, IL, USA from 2011-2013. Wintertime mortality of M. x giganteus was subsequently assessed. It was proposed that areas with higher seasonal snowfall in the US Midwest may be favorable for M. x giganteus sustainability and expansion due to the significant insulating effect

  17. Generation of Multi-band Chorus by Lower Band Cascade in the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Gao, X.; Lu, Q.; Chen, L.; Bortnik, J.; Li, W.; Wang, S.

    2016-12-01

    Chorus waves are intense electromagnetic whistler-mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the THEMIS satellite, we observed two special chorus events, which are called as multi-band chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multi-band chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is caused by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler-mode chorus in the Earth's magnetosphere.

  18. Generation of Multiband Chorus in the Earth's Magnetosphere: 1-D PIC Simulation

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Ke, Yangguang; Lu, Quanming; Chen, Lunjin; Wang, Shui

    2017-01-01

    Multiband chorus waves, where the frequency of upper band chorus is about twice that of lower band chorus, have recently been reported based on THEMIS observations. The generation of multiband chorus waves is attributed to the mechanism of lower band cascade, where upper band chorus is excited via the nonlinear coupling process between lower band chorus and the associated density mode with the frequency equal to that of lower band chorus. In this letter, with a one-dimensional (1-D) particle-in-cell (PIC) simulation model, we have successfully reproduced multiband chorus waves. During the simulation, the significant density fluctuation is driven by the fluctuating electric field along the wave vector of the pump wave (lower band chorus), which can be directly observed in this self-consistent plasma system. Then, the second harmonic of the pump whistler-mode wave (upper band chorus) is generated. After quantitatively analyzing resonant conditions among wave numbers, we can confirm that the generation is caused due to the coupling between the pump wave and the density fluctuation along its wave vector. The third harmonic can also be excited through lower band cascade if the pump whistler-mode wave has a sufficiently large amplitude. Our simulation results not only provide a theoretical support to the mechanism of lower band cascade to generate multiband chorus but also propose a new pattern of evolution for whistler-mode waves in the Earth's magnetosphere.

  19. Tackling the Triple-Threat Genome of Miscanthus x giganteus (2010 JGI User Meeting)

    SciTech Connect

    Moose, Steve

    2010-03-25

    Steve Moose from the University of Illinois at Urbana-Champaign and the Energy Biosciences Institute on "Tackling the Triple-Threat Genome of Miscanthus x giganteus" on March 25, 2010 at the 5th Annual DOE JGI User Meeting

  20. Tackling the Triple-Threat Genome of Miscanthus x giganteus (2010 JGI User Meeting)

    ScienceCinema

    Moose, Steve

    2016-07-12

    Steve Moose from the University of Illinois at Urbana-Champaign and the Energy Biosciences Institute on "Tackling the Triple-Threat Genome of Miscanthus x giganteus" on March 25, 2010 at the 5th Annual DOE JGI User Meeting

  1. Analysis of Simultaneous Hiss and Chorus Ground & In Situ Observations

    NASA Astrophysics Data System (ADS)

    Hosseini, P.; Golkowski, M.

    2016-12-01

    The dynamic evolution of the radiation belts is believed to be controlled in large part by two separate but related classes of naturally occurring plasma waves: ELF/VLF chorus and hiss emissions. These waves can be observed both in situ on spacecraft and at ground-based stations. Recent observational and theoretical works suggest that high resolution analysis of the spectral features of both hiss and chorus emissions can provide insight into generation processes and be used to validate existing theories. However, ground observation are limited to the portion of magnetospheric waves that are able to propagate to low altitudes and penetrate through the ionosphere. The whistler mode wave is intrinsically right hand circularly polarized (RHCP) in the magnetosphere, and becomes more linear with increased propagation distance in the Earth-ionosphere waveguide. We use wave polarization to differentiate magnetospheric and ionospheric effects in ground based observations. Observations are compared to simulations using the finite difference time domain method to track the effect of propagation in the Earth-ionosphere waveguide on polarization. Ionospheric exit point of the emissions, have been further determined by calculating the angle of arrival, which shows a rotation of exit points along with transition of hiss to chorus emissions. Simultaneous THEMIS spacecraft data have been investigated and show agreement with the observed transitions in our ground based observations. The plasmapause is seen to erode and density structures develop, providing insight into the relationship of chorus and hiss and the plasmapause boundary.

  2. The Chorus Conflict and Loss of Separation Resolution Algorithms

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Hagen, George E.; Maddalon, Jeffrey M.

    2013-01-01

    The Chorus software is designed to investigate near-term, tactical conflict and loss of separation detection and resolution concepts for air traffic management. This software is currently being used in two different problem domains: en-route self- separation and sense and avoid for unmanned aircraft systems. This paper describes the core resolution algorithms that are part of Chorus. The combination of several features of the Chorus program distinguish this software from other approaches to conflict and loss of separation resolution. First, the program stores a history of state information over time which enables it to handle communication dropouts and take advantage of previous input data. Second, the underlying conflict algorithms find resolutions that solve the most urgent conflict, but also seek to prevent secondary conflicts with the other aircraft. Third, if the program is run on multiple aircraft, and the two aircraft maneuver at the same time, the result will be implicitly co-ordinated. This implicit coordination property is established by ensuring that a resolution produced by Chorus will comply with a mathematically-defined criteria whose correctness has been formally verified. Fourth, the program produces both instantaneous solutions and kinematic solutions, which are based on simple accel- eration models. Finally, the program provides resolutions for recovery from loss of separation. Different versions of this software are implemented as Java and C++ software programs, respectively.

  3. Phylogenetic and ecological determinants of the neotropical dawn chorus

    PubMed Central

    Berg, Karl S; Brumfield, Robb T; Apanius, Victor

    2006-01-01

    The concentration of avian song at first light (i.e. the dawn chorus) is widely appreciated, but has an enigmatic functional significance. One widely accepted explanation is that birds are active at dawn, but light levels are not yet adequate for foraging. In forest communities, the onset to singing should thus be predictable from the species' foraging strata, which is ultimately related to ambient light level. To test this, we collected data from a tropical forest of Ecuador involving 57 species from 27 families of birds. Time of first song was a repeatable, species-specific trait, and the majority of resident birds, including non-passerines, sang in the dawn chorus. For passerine birds, foraging height was the best predictor of time of first song, with canopy birds singing earlier than birds foraging closer to the forest floor. A weak and opposite result was observed for non-passerines. For passerine birds, eye size also predicted time of first song, with larger eyed birds singing earlier, after controlling for body mass, taxonomic group and foraging height. This is the first comparative study of the dawn chorus in the Neotropics, and it provides the first evidence for foraging strata as the primary determinant of scheduling participation in the dawn chorus of birds. PMID:16627286

  4. Traditional Greek Choruses and the Education of Girls.

    ERIC Educational Resources Information Center

    Ingalls, Wayne B.

    1999-01-01

    Explores the form and content of the education that aristocratic girls received in ancient Greece in the context of their preparation for performance in lyric choruses. Offers background information on the function and structure of choral activity in Greek society. (CMK)

  5. Generation mechanism of whistler-mode chorus emissions

    NASA Astrophysics Data System (ADS)

    Omura, Yoshiharu

    We describe the nonlinear dynamics of resonant electrons interacting with a coherent whistler-mode wave and the formation of electromagnetic electron holes or hills in the velocity phase space. In the presence of the inhomogeneity due to the frequency variation and the gradient of the magnetic field, the electron holes or hills result in resonant currents generating rising-tone emissions (1, 2) or falling-tone emissions (3), respectively. After formation of a coherent wave at the maximum linear growth rate, triggering of the nonlinear wave growth takes place when the wave amplitude is close to the optimum wave amplitude (4). The wave amplitude also has to be above the threshold amplitude (2) so that the nonlinear wave growth can occur as an absolute instability at the magnetic equator. The triggering process is repeated at progressively higher frequencies in the case of a rising-tone emission, generating subpackets of a chorus element. We also describe the mechanism of nonlinear wave damping due to quasi-oblique propagation from the equator (2), which results in the formation of a gap at half the electron cyclotron frequency, separating a long rising-tone chorus emission into the upper-band and lower-band chorus emissions (5). *References (1) Y. Omura,Y. Katoh, and D. Summers, Theory and simulation of the generation of whistler-mode chorus, J. Geophys. Res., 113, A04223, 2008. (2) Y. Omura, , M. Hikishima, Y. Katoh, D. Summers, and S. Yagitani, Nonlinear mechanisms of lower band and upper band VLF chorus emissions in the magnetosphere, J. Geophys. Res., 114, A07217, 2009. (3) Nunn, D., and Y. Omura, A computational and theoretical analysis of falling frequency VLF emissions, J. Geophys. Res., 117, A08228, 2012. (4) Omura, Y., and D. Nunn, Triggering process of whistler mode chorus emissions in the magnetosphere, J. Geophys. Res., 116, A05205, 2011. (5) S. Kurita, Y. Katoh, Y. Omura, V. Angelopoulos, C. M. Cully, O. Le Contel, and H. Misawa, THEMIS observation of

  6. Chorus Wave Scattering Responsible for the Dayside Diffuse Auroral Precipitation

    NASA Astrophysics Data System (ADS)

    Ni, B.; Nishimura, T.; Bortnik, J.; Thorne, R. M.; Li, W.; Angelopoulos, V.; Ebihara, Y.; Weatherwax, A. T.

    2012-12-01

    We perform a comprehensive theoretical and numerical analysis on the conjunction measurements of dayside diffuse aurora and whistler-mode chorus waves by the South Pole all-sky imager and THEMIS spacecraft at 16 -18 UT on August 13, 2009. A high correlation is identified between the intensities of the diffuse aurora at 557.7 nm near the THEMIS ionospheric footprints and chorus emissions. Using the simultaneous wave, plasma density and particle datasets of THEMIS observations, we compute the matrices of bounce-averaged diffusion coefficients due to chorus wave scattering in the realistic magnetosphere at a series of representative time stamps, which are subsequently utilized to quantitatively compare with the rate of strong diffusion for evaluating the energy dependent loss cone filling index associated with chorus-induced pitch angle scattering. Fits of Maxwellian-type energy spectrum to the modeled electron differential fluxes inside the loss cone produce a temporal variation of the total energy flux and characteristic energy of precipitating electrons. The obtained dominant precipitation energies are within 2 - 5 keV, which agrees well with the major electron population for the dayside green-line aurora excitation. The modeled change of the total precipitation energy flux is remarkably consistent with that of the observed green-line diffuse aurora intensity. The trend of decreases and increases in the aurora luminosity is also reasonably reproduced in a time consistent manner. Through a systematic combination of quasi-linear theory, realistic non-dipolar magnetic field mapping, and the concept of strong diffusion on the basis of conjugated space and ground observations, we have demonstrated that dayside chorus scattering can dominantly account for the dayside green-line diffuse aurora activity, while variations in electron differential flux also play a role. In addition, changes in the ambient density can affect the portion of diffuse auroral electrons that

  7. Modulation of whistler mode chorus waves: 2. Role of density variations

    NASA Astrophysics Data System (ADS)

    Li, W.; Bortnik, J.; Thorne, R. M.; Nishimura, Y.; Angelopoulos, V.; Chen, L.

    2011-06-01

    Modulation of whistler mode chorus waves, which plays an important role in driving the pulsating aurora and other processes related to energetic electron dynamics, is an interesting but a long-standing unresolved problem. Here we utilize in situ observations from the THEMIS spacecraft to investigate the role of density variations in the modulation of the chorus wave amplitude, which forms a complementary study to the modulation of chorus by compressional Pc4-5 pulsations presented in a companion paper. We show that these density variations are correlated remarkably well with modulated chorus intensity and typically occur on a timescale of a few seconds to tens of seconds. Both density depletions (DD) and density enhancements (DE) are frequently correlated with increases in chorus wave amplitudes. Furthermore, density enhancements cause a lowering of the central frequencies of the generated chorus waves and vice versa. DD events are more likely to be related to quasi-periodic chorus emissions and thus may be related to the generation of the pulsating aurora. A systematic survey of both DD and DE events shows that DD events preferentially occur between premidnight and dawn, whereas DE events dominantly occur from dawn to noon. We also evaluate the growth rates of chorus waves using linear theory for both DD and DE events and show that both density depletions and enhancements can lead to an intensification of chorus wave growth. However, other potential mechanisms for chorus intensification caused by density variations such as wave trapping by density crests and troughs cannot be excluded.

  8. Amplification of exo-hiss into low-frequency chorus following substorm injection

    NASA Astrophysics Data System (ADS)

    Gao, Z.; Su, Z.

    2016-12-01

    Whistler-mode chorus waves contribute significantly to the acceleration of radiation belt electrons. Chorus with frequency below 0.1 fce (fce is the equatorial electron gyro-frequency) has been identified as the low-frequency chorus. How such low-frequency chorus waves are generated remains an unanswered question. Here we propose a new candidate generation mechanism that exo-hiss waves can serve as the source of low-frequency chorus. Exo-hiss is usually believed to be the leaked plasmaspheric hiss from the high-density plasmasphere into the low-density plasmatrough. Both Van Allen Probes observations and linear instability analyses support that exo-hiss can be effectively amplified into low-frequency chorus by the substorm-injected anisotropic electrons at energies around 100 keV.

  9. Transverse Dimensions of Chorus in the Source Region

    NASA Technical Reports Server (NTRS)

    Santolik, O.; Gurnett, D. A.

    2003-01-01

    We report measurement of whistler-mode chorus by the four Cluster spacecraft at close separations. We focus our analysis on the generation region close to the magnetic equatorial plane at a radial distance of 4.4 Earth's radii. We use both linear and rank correlation analysis to define perpendicular dimensions of the sources of chorus elements below one half of the electron cyclotron frequency. Correlation is significant throughout the range of separation distances of 60-260 km parallel to the field line and 7-100 km in the perpendicular plane. At these scales, the correlation coefficient is independent for parallel separations, and decreases with perpendicular separation. The observations are consistent with a statistical model of the source region assuming individual sources as gaussian peaks of radiated power with a common half-width of 35 km perpendicular to the magnetic field. This characteristic scale is comparable to the wavelength of observed waves.

  10. Transverse Dimensions of Chorus in the Source Region

    NASA Technical Reports Server (NTRS)

    Santolik, O.; Gurnett, D. A.

    2003-01-01

    We report measurement of whistler-mode chorus by the four Cluster spacecraft at close separations. We focus our analysis on the generation region close to the magnetic equatorial plane at a radial distance of 4.4 Earth's radii. We use both linear and rank correlation analysis to define perpendicular dimensions of the sources of chorus elements below one half of the electron cyclotron frequency. Correlation is significant throughout the range of separation distances of 60-260 km parallel to the field line and 7-100 km in the perpendicular plane. At these scales, the correlation coefficient is independent for parallel separations, and decreases with perpendicular separation. The observations are consistent with a statistical model of the source region assuming individual sources as gaussian peaks of radiated power with a common half-width of 35 km perpendicular to the magnetic field. This characteristic scale is comparable to the wavelength of observed waves.

  11. The CHORUS honeycomb tracker and its bitstream electronics

    NASA Astrophysics Data System (ADS)

    Uiterwijk, J. W. E.; van Beuzekom, M. G.; van Dantzig, R.; van der Graaf, H.; de Jong, M.; Kok, J. W.; Konijn, J.; Litmaath, M. F.; Metselaar, J. P. M.; Oldeman, R. G. C.; Panman, J.; van der Poel, C. J. A. F.; Visschers, J. L.

    1998-02-01

    The CHORUS experiment searches for ν μ↔ν τ oscillation. To aid in the momentum reconstruction of charged hadrons, a honeycomb tracker was built with three orientations of six planes each. The planes are manufactured by point-welding together two precision folded conductive polycarbonate foils, forming hexagonal tubes with 30 μm thick anode wires in the center. The honeycomb tracker in CHORUS is read out using a bitstream principle. The amplified signal of each wire is binary sampled every 5 ns and stored in a 256 bit circular buffer, implemented in dual-port memories. This technique allows a full reconstruction of a 1.28 μs history of each wire. Eighteen cards, each handling 72 wires, are read out over a single flat cable using a card-to-card pipeline.

  12. Poynting vector and wave vector directions of equatorial chorus

    NASA Astrophysics Data System (ADS)

    Taubenschuss, Ulrich; Santolík, Ondřej; Breuillard, Hugo; Li, Wen; Le Contel, Olivier

    2016-12-01

    We present new results on wave vectors and Poynting vectors of chorus rising and falling tones on the basis of 6 years of THEMIS (Time History of Events and Macroscale Interactions during Substorms) observations. The majority of wave vectors is closely aligned with the direction of the ambient magnetic field (B0). Oblique wave vectors are confined to the magnetic meridional plane, pointing away from Earth. Poynting vectors are found to be almost parallel to B0. We show, for the first time, that slightly oblique Poynting vectors are directed away from Earth for rising tones and toward Earth for falling tones. For the majority of lower band chorus elements, the mutual orientation between Poynting vectors and wave vectors can be explained by whistler mode dispersion in a homogeneous collisionless cold plasma. Upper band chorus seems to require inclusion of collisional processes or taking into account azimuthal anisotropies in the propagation medium. The latitudinal extension of the equatorial source region can be limited to ±6∘ around the B0 minimum or approximately ±5000 km along magnetic field lines. We find increasing Poynting flux and focusing of Poynting vectors on the B0 direction with increasing latitude. Also, wave vectors become most often more field aligned. A smaller group of chorus generated with very oblique wave normals tends to stay close to the whistler mode resonance cone. This suggests that close to the equatorial source region (within ˜20∘ latitude), a wave guidance mechanism is relevant, for example, in ducts of depleted or enhanced plasma density.

  13. Bayesian Spectral Analysis of Chorus Sub-Elements

    NASA Astrophysics Data System (ADS)

    Crabtree, C. E.; Tejero, E. M.; Ganguli, G.; Hospodarsky, G. B.; Kletzing, C.

    2016-12-01

    We develop a Bayesian spectral analysis technique that calculates the probability distribution functions of a superposition of wave-modes each described by a linear growth rate, a frequency and a chirp rate. The Bayesian framework has a number of advantages, including 1) reducing the parameter space by integrating over the amplitude and phase of the wave, 2) incorporating the data from each channel to determine the model parameters such as frequency which leads to high resolution results in frequency and time, 3) the ability to consider the superposition of waves where the wave-parameters are closely spaced, 4) the ability to directly calculate the expectation value of wave parameters without resorting to ensemble averages, 5) the ability to calculate error bars on model parameters. We examine one rising-tone chorus element in detail from a disturbed time on November 14, 2012 using burst mode waveform data of the three components of the electric and magnetic field from the EMFISIS instrument on board NASA's Van Allen Probes. The results of the analysis demonstrate that whistler mode chorus sub-elements are composed of almost linear waves that are nearly parallel propagating with continuously changing wave parameters such as frequency and wave-vector. The change of wave-vector as a function of time is a three-dimensional phenomenon suggesting that 2D simulations may not accurately represent chorus. The initial parts of the sub-elements are in good agreement with the analytical theory of Omura et al. 2008. However, between sub-elements the wave parameters of the dominant mode undergo discrete changes in frequency and wave-vector. Near the boundary of sub-elements multiple waves are observed such that the evolution of the waves is reminiscent of wave-wave processes such as parametric decay or induced scattering by particles. These nonlinear processes are signatures of weak turbulence and may affect the saturation of the whistler-mode chorus instability.

  14. Predicting emergence, chorusing, and oviposition of periodical cicadas.

    PubMed

    Oberdörster, Uta; Grant, Peter R

    2006-02-01

    Periodical cicadas in the genus Magicicada have an unusual life history that includes an exceptionally long life cycle and a massive, synchronized emergence. Distributions in woodland habitat are extremely patchy, and an unresolved problem is how the patchiness is generated and maintained. We undertook a study in Princeton, New Jersey, USA, to determine if habitat factors such as tree height, distance to the nearest neighbor, and amount of foliage influence distributions of nymphal emergences, centers of chorusing aggregations, and oviposition sites. Emerging nymphs were counted, chorus centers were identified by measuring decibel levels of their songs, and oviposition was estimated from the foliage "flags" that are produced by trees in response to the damage caused by egg-laying. All three distributions were mapped on 50 trees in a human-managed area of 75 x 130 m. We were unable to identify habitat features that were associated with the distribution of emergences, except that tulip trees (Liriodendron) had significantly fewer emergences than two other genera, ash (Fraxinus) and beech (Fagus). Using multiple linear regression analysis, we found that the distribution of emergences was the best predictor of the distribution of chorus centers and oviposition sites. In an analysis of ash trees alone, tree height and spacing, in addition to cicada emergences, predicted chorus centers and oviposition incidence. Thus the distribution of the offspring generation (oviposition) is shown to be similar to the parental generation (emergence). We suggest that their stability is maintained across generations by extremely low dispersal and mutual attraction. Aggregations may be thought of as self-perpetuating, randomly distributed assemblages, initially established through the interaction of factors, including successful exploitation of underground resources, and avoidance of fungal disease and aboveground predation in the development of high-density mating aggregations.

  15. Agronomic Experiences with Miscanthus x giganteus in Illinois, USA

    NASA Astrophysics Data System (ADS)

    Pyter, Richard; Heaton, Emily; Dohleman, Frank; Voigt, Tom; Long, Stephen

    Since 2002, researchers at the University of Illinois, Urbana-Champaign, Illinois, have been studying the perennial warm-season grass Miscanthus × giganteus (M. × g.) to determine its potential as a biomass feedstock. M. × g. originated in Japan and is a hybrid believed to have M. sinensis and M. sacchariflorus as its parents. Until recently, it was used as a landscape plant in the United States, but it is now the subject of research interest because of its potentially great biomass production. In central Illinois, M. × g. begins growth in April, typically reaches 2 m by the end of May, and is normally greater than 3 m by the end of September. The grass is sterile and propagated asexually using plantlets produced in tissue culture or by rhizome divisions. Following field planting, it generally takes at least three growing seasons to become fully established and reach optimal biomass production. In central Illinois, the senesced stems are harvested from early December through early March and can potentially be treated to produce ligno-cellulosic ethanol. In University of Illinois, research started in 2002. M. × g. produced an annual average of 22.0 t/ha in northern Illinois, 34.7 t/ha in central Illinois, and 35.4 t/ha in southern Illinois per year in 2004, 2005, and 2006.

  16. Development and feeding of fall armyworm on Miscanthus x giganteus and switchgrass.

    PubMed

    Prasifka, J R; Bradshaw, J D; Meagher, R L; Nagoshi, R N; Steffey, K L; Gray, M E

    2009-12-01

    Observations of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development, and feeding preferences on leaf tissue from M. x giganteus and switchgrass, Panicum virgatum L. Survival from hatch to pupation was >70 and 50% for fall armyworms reared on switchgrass and M. x giganteus, respectively, although survival of the S. frugiperda rice strain was significantly greater than the corn strain on both crops. Developmental times from hatch to pupation or adult emergence showed effects of crop and S. frugiperda host strain, but analysis of an interaction revealed developmental times for the rice strain were similar on both crops, whereas corn strain larvae showed delayed development on M. x giganteus relative to switchgrass. Analysis of larval (10 d) and pupal masses showed a similar pattern, with effects of crop and an interaction (at 10 d), but only the mass of corn strain larvae feeding on M. x giganteus was reduced relative to the other crop and strain combinations. In choice tests, neonates of both corn and rice strains showed a strong preference for feeding on young tissues rather than mature leaves of M. x giganteus or switchgrass, but they also clearly favored corn, Zea mays L., leaves over either of the perennial grasses. Results indicate both plants are potential hosts for S. frugiperda, but additional information is needed to understand under which scenarios and to what degree fall armyworms may damage perennial grasses grown for biofuel production.

  17. Entomopathogenic effect of Aspergillus giganteus and Penicillium corylophilum on two triatomine vectors of Chagas disease.

    PubMed

    da Costa, Gisela Lara; de Moraes, Aurea Maria Lage; Galvão, Cleber

    2003-01-01

    Two strains, Penicillium corylophilum and Aspergillus giganteus, of the most frequent species found in a survey of triatomines, were used for bioassays in the second and fourth nymphs stage of Triatoma infestans and Panstrongylus megistus. Two procedures, bite and pulverization, were used and compared. A. giganteus was most effective, causing mortality in at least 50% of the nymphs of the two species tested with exception of the nymphs of the fourth stage of P. megistus. Variation in entomopathogenic capacity of the fungal species were observed in the experiments. The two procedures used proved effective.

  18. Confronting Homophobia at School: High School Students and the Gay Men's Chorus of Los Angeles

    ERIC Educational Resources Information Center

    Knotts, Greg; Gregorio, Dominic

    2011-01-01

    This study discusses student responses to curriculum taught by the Gay Men's Chorus of Los Angeles to choral students in local high schools. The Gay Men's Chorus of Los Angeles's A-LIVE Music Project brings live music and standards-driven curriculum to high school youth with the express purpose of teaching content in innovative ways and…

  19. Evolution of chorus emissions into plasmaspheric hiss observed by Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhou, Qinghua; Xiao, Fuliang; Yang, Chang; Liu, Si; He, Yihua; Wygant, J. R.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.

    2016-05-01

    The two classes of whistler mode waves (chorus and hiss) play different roles in the dynamics of radiation belt energetic electrons. Chorus can efficiently accelerate energetic electrons, and hiss is responsible for the loss of energetic electrons. Previous studies have proposed that chorus is the source of plasmaspheric hiss, but this still requires an observational confirmation because the previously observed chorus and hiss emissions were not in the same frequency range in the same time. Here we report simultaneous observations form Van Allen Probes that chorus and hiss emissions occurred in the same range ˜300-1500 Hz with the peak wave power density about 10-5 nT2/Hz during a weak storm on 3 July 2014. Chorus emissions propagate in a broad region outside the plasmapause. Meanwhile, hiss emissions are confined inside the plasmasphere, with a higher intensity and a broader area at a lower frequency. A sum of bi-Maxwellian distribution is used to model the observed anisotropic electron distributions and to evaluate the instability of waves. A three-dimensional ray tracing simulation shows that a portion of chorus emission outside the plasmasphere can propagate into the plasmasphere and evolve into plasmaspheric hiss. Moreover, hiss waves below 1 kHz are more intense and propagate over a broader area than those above 1 kHz, consistent with the observation. The current results can explain distributions of the observed hiss emission and provide a further support for the mechanism of evolution of chorus into hiss emissions.

  20. Parameterization and Regression Analysis of Off-Equatorial Chorus Waves for Inclusion in Radiation Belt Models

    NASA Astrophysics Data System (ADS)

    Bunch, N. L.; Spasojevic, M.; Shprits, Y.; Golden, D. I.

    2011-12-01

    Outer radiation belt fluxes vary by orders of magnitude on time scales of hours to days (Li et al., 2001). Wave-particle interactions involving lower band chorus waves are thought to play a major role in acceleration and loss of energetic electrons in the outer belt. Wave particle interactions involving chorus and the highest energy electrons (>MeV) is possible only at latitudes above about 20° (Shprits and Ni, 2009). Despite their perceived importance in controlling energetic electron populations in the radiation belts, relatively insubstantial statistical characterization exists from which to base radiation belt model inputs for chorus. Recent investigations employing a database of chorus events observed by the Polar spacecraft have begun to characterize chorus waves at 20° magnetic latitude and above (Bunch et al., 2011). This study utilizes the Polar wave database to parameterize wave intensities as a function of spatial location and geomagnetic driving conditions (e.g. AE, Vsw, Kp, etc.). The relative correlation of chorus occurrence and amplitude with geomagnetic conditions is also examined using an auto regressive moving average (ARMA) technique for non-independent observations, such as those made by orbiting spacecraft. Regression analysis shows significant correlation of chorus with increased AE, Vsw, and Kp, and much lower correlations with proton density, and pressure. Wave parameterizations show, for fixed range in L, an increase in chorus amplitude with magnetic latitude in the dawn sector. Amplitudes appear more constant over a range of latitudes at noon, particularly for increased activity levels. These results represent significant steps forward toward a more complete characterization of the chorus wave environment and understanding the role chorus plays in regulation of the radiation belt environment.

  1. Role of the plasmapause in dictating the ground accessibility of ELF/VLF chorus

    NASA Astrophysics Data System (ADS)

    Golden, D. I.; Spasojevic, M.; Foust, F. R.; Lehtinen, N. G.; Meredith, N. P.; Inan, U. S.

    2010-11-01

    This study explores the manner in which the plasmapause is responsible for dictating which magnetospheric source regions of ELF/VLF chorus are able to propagate to and be received by midlatitude stations on the ground. First, we explore the effects of plasmapause extent on ground-based observations of chorus via a 3 month study of ground-based measurements of chorus at Palmer Station, Antarctica (L = 2.4, 50°S geomagnetic latitude), and data on the plasmapause extent from the IMAGE EUV instrument. It is found that chorus normalized occurrence peaks when the plasmapause is at L ˜ 2.6, somewhat higher than Palmer's L shell, and that this occurrence peak persists across a range of observed chorus frequencies. Next, reverse ray tracing is employed to evaluate the portion of the equatorial chorus source region, distributed in radial distance and wave normal, from which chorus is able to reach Palmer Station via propagation in a nonducted mode. The results of ray tracing are similar to those of observations, with a peak of expected occurrence when the plasmapause is at L ˜ 3. The exact location of the peak is frequency dependent. This supports the conclusion that the ability of chorus to propagate to low altitudes and the ground is a strong function of instantaneous plasmapause extent and that peak occurrence of chorus at a given ground station may occur when the L shell of the plasmapause is somewhat beyond that of the observing station. These results also suggest that chorus observed on the ground at midlatitude stations propagates predominantly in the nonducted mode.

  2. Control Over the Ground-Accessibility of ELF/VLF Chorus by a Discriminating Plasmasphere

    NASA Astrophysics Data System (ADS)

    Golden, D. I.; Spasojevic, M.; Inan, U. S.

    2010-12-01

    This study explores the manner in which the plasmapause is responsible for dictating which magnetospheric source regions of ELF/VLF chorus are able to propagate to and be received by mid-latitude stations on the ground. First, we explore the effects of plasmapause extent on ground-based observations of chorus via a three-month study of ground-based measurements of chorus at Palmer Station, Antarctica (L=2.4, 50°S geomagnetic latitude) and data on the plasmapause extent from the IMAGE EUV instrument. It is found that chorus normalized occurrence peaks when the plasmapause is at L ~ 2.6, somewhat higher than Palmer's L-shell, and that this occurrence peak persists across a range of observed chorus frequencies. Next, reverse raytracing is employed to evaluate the portion of the equatorial chorus source region, distributed in radial distance and wave normal, from which chorus is able to reach Palmer station via propagation in a non-ducted mode. The results of raytracing are similar to those of observations, with a peak of expected occurrence when the plasmapause is at L ~ 3. The exact location of the peak is frequency-dependent. This supports the conclusion that the ability for chorus to propagate to low altitudes and the ground is a strong function of instantaneous plasmapause extent, and that peak occurrence of chorus at a given ground station may occur when the L-shell of the plasmapause is somewhat beyond that of the observing station. These results also suggest that chorus observed on the ground at mid-latitude stations propagates predominantly in the non-ducted mode.

  3. Antiphonal four-part synchronized chorusing in a Neotropical wren

    PubMed Central

    Mann, Nigel I; Dingess, Kimberly A; Slater, P.J.B

    2005-01-01

    Plain-tailed wrens (Thryothorus euophrys) live in groups that sing synchronized choruses, the contributions of females and males alternating with each other in cycles, within which each sex sings two of the four parts, the whole achieving near perfect synchrony. As each bird has a repertoire of ca 20 phrases of each type, the synchrony also requires them to choose the same type at the same time as others of their sex. Songs can last up to 2 min, during which individuals join in and drop out. This must be one of the most complex singing performances yet described in a non-human animal. PMID:17148310

  4. Genetic and developmental studies of albino chorus frogs

    USGS Publications Warehouse

    Corn, Paul Stephen

    1986-01-01

    Albino (amelanic) adult chorus frogs (Pseudacris triseriata) occurred with frequencies of 7 percent in 1981 and 12 percent in 1982 in breeding aggregations at a pond in the foothills of the Colorado Front Range. Laboratory matings and examination of albino egg masses suggest that the absence of melanin is due to a recessive allele. The albino phenotype displayed no deficiencies in survival of embryos, rates of embryo or larval development, or rates of growth of juvenile frogs. The absence of abnormalities in development or growth suggests that the a allele in P. triseriata has an action different from albino alleles studied previously in anurans.

  5. Uridine from Pleurotus giganteus and Its Neurite Outgrowth Stimulatory Effects with Underlying Mechanism

    PubMed Central

    Phan, Chia-Wei; David, Pamela; Wong, Kah-Hui; Naidu, Murali; Sabaratnam, Vikineswary

    2015-01-01

    Neurodegenerative diseases are linked to neuronal cell death and impairment of neurite outgrowth. An edible mushroom, Pleurotus giganteus was found to stimulate neurite outgrowth in vitro but the chemical constituents and the underlying mechanism is yet to be elucidated. The chemical constituents of P. giganteus (linoleic acid, oleic acid, cinnamic acid, caffeic acid, p-coumaric acid, succinic acid, benzoic acid, and uridine) were tested for neurite outgrowth activity. Uridine (100 μM) was found to increase the percentage of neurite-bearing cells of differentiating neuroblastoma (N2a) cells by 43.1±0.5%, which was 1.8-fold higher than NGF (50 ng/mL)-treated cells. Uridine which was present in P. giganteus (1.80±0.03 g/100g mushroom extract) increased the phosphorylation of extracellular-signal regulated kinases (ERKs) and protein kinase B (Akt). Further, phosphorylation of the mammalian target of rapamycin (mTOR) was also increased. MEK/ERK and PI3K-Akt-mTOR further induced phosphorylation of cAMP-response element binding protein (CREB) and expression of growth associated protein 43 (GAP43); all of which promoted neurite outgrowth of N2a cells. This study demonstrated that P. giganteus may enhance neurite outgrowth and one of the key bioactive molecules responsible for neurite outgrowth is uridine. PMID:26565787

  6. Autohydrolysis of Miscanthus x giganteus for the production of xylooligosaccharides (XOS): Kinetics, characterization and recovery

    USDA-ARS?s Scientific Manuscript database

    The optima conditions of production and purification of xylooligosaccharides (XOS) from Miscanthus x giganteus (MxG) were investigated. Using autohydrolysis, XOS were produced at 160, 180 and 200°C at 60, 20 and 5 min, respectively. XOS yield up to 13.5% (w/w) of initial biomass and 69.2% (w/w) of x...

  7. Under Cover: Secrets to Using Companion Crops in Establishment of M. x Giganteus

    USDA-ARS?s Scientific Manuscript database

    Miscanthus x giganteus is of interest for bioenergy because of its high biomass yields and low input requirements. The deep-rooted perennial grass has garnered attention for potential to build soil organic matter and sequester atmospheric carbon, particularly on marginal lands. There is a risk howev...

  8. Uridine from Pleurotus giganteus and Its Neurite Outgrowth Stimulatory Effects with Underlying Mechanism.

    PubMed

    Phan, Chia-Wei; David, Pamela; Wong, Kah-Hui; Naidu, Murali; Sabaratnam, Vikineswary

    2015-01-01

    Neurodegenerative diseases are linked to neuronal cell death and impairment of neurite outgrowth. An edible mushroom, Pleurotus giganteus was found to stimulate neurite outgrowth in vitro but the chemical constituents and the underlying mechanism is yet to be elucidated. The chemical constituents of P. giganteus (linoleic acid, oleic acid, cinnamic acid, caffeic acid, p-coumaric acid, succinic acid, benzoic acid, and uridine) were tested for neurite outgrowth activity. Uridine (100 μM) was found to increase the percentage of neurite-bearing cells of differentiating neuroblastoma (N2a) cells by 43.1 ± 0.5%, which was 1.8-fold higher than NGF (50 ng/mL)-treated cells. Uridine which was present in P. giganteus (1.80 ± 0.03 g/100g mushroom extract) increased the phosphorylation of extracellular-signal regulated kinases (ERKs) and protein kinase B (Akt). Further, phosphorylation of the mammalian target of rapamycin (mTOR) was also increased. MEK/ERK and PI3K-Akt-mTOR further induced phosphorylation of cAMP-response element binding protein (CREB) and expression of growth associated protein 43 (GAP43); all of which promoted neurite outgrowth of N2a cells. This study demonstrated that P. giganteus may enhance neurite outgrowth and one of the key bioactive molecules responsible for neurite outgrowth is uridine.

  9. Yield potential and nitrogen requirements of Miscanthus × giganteus on eroded soils

    USDA-ARS?s Scientific Manuscript database

    Miscanthus × giganteus yield and fertilizer N requirements have been well studied in Europe and parts of the United States, but few reports have investigated its production on eroded claypan soils economically marginal for grain crops. This study was conducted to evaluate yield potential and fertili...

  10. Potential biomass reductions to Miscanthus × giganteus by stem-boring caterpillars

    USDA-ARS?s Scientific Manuscript database

    Injury from stem-boring caterpillars has been observed on the perennial grass Miscanthus × giganteus Greef and Deuter ex Hodkinson and Renvoize in both its native and introduced ranges. Because some species causing stem injury in the United States have not been identified, potential biomass reducti...

  11. Draft Genome Sequence of Three Endophyte Strains of Pseudomonas fluorescens Isolated from Miscanthus giganteus

    PubMed Central

    Moreira, António S.; Lloyd, Andrew; Lally, Richard D.; Galbally, Paul T.; Ryan, David

    2016-01-01

    We report here the draft genome sequence of three Pseudomonas fluorescens strains (L111, L228, and L321) isolated from Miscanthus giganteus. The draft genome analyses uncovered a group of genes involved in the biosynthesis of secondary metabolites and for plant growth promotion. PMID:27738024

  12. Miscanthus x giganteus production: Meta-analysis, field study and mathematical modeling

    NASA Astrophysics Data System (ADS)

    Miguez, Fernando E.

    This is a comprehensive study of the potential of M. x giganteus as a biomass crop for energy production. The study looks at the past, present and future of M. x giganteus for its potential for dry biomass production. In Chapter 1 the published M. x giganteus literature, including 31 European studies, was analyzed using non-linear mixed models. This quantitative review of the literature (i.e. meta-analysis) revealed patterns across and within growing seasons. This analysis not only revealed the effects of the growing season, planting density and nitrogen (N) fertilizer but also provided a measure of uncertainty about these effects. More importantly, it provided statistical models which are essentially testable hypotheses. These models were used in Chapter 2 to predict dry biomass considering effects of growing season, planting density and N fertilizer in Illinois. In Chapter 2 M. x giganteus and P. virgatum were investigated in a field study at two locations at Savoy and Perry, IL in 2006. This field study evaluated the performance of M. x giganteus and P. virgatum with respect to their response to N fertilizer and hairy vetch (a winter legume). Variables analyzed included light interception, greenness and dry biomass. In Chapter 3 a mechanistic model, WIMOVAC, was descried and parameterized for simulating M. x giganteus production. The model showed great potential at predicting photosynthesis, leaf area index and dry biomass partitioning in M. x giganteus European experiments. HE Chapter 4, the model described in Chapter 3 was re-implemented and improved, termed BIOCRO with the objective of rigorously estimating key parameters related to dry biomass partitioning. The Bayesian statistical framework for parameter estimation was achieved through the use of Markey chain Monte Carlo methods. The algorithm proposed can be used to estimate parameters in large complex models as the one proposed here. The future of this research points to novel ways in which current

  13. Visualizing sound: counting wolves by using a spectral view of the chorus howling.

    PubMed

    Passilongo, Daniela; Mattioli, Luca; Bassi, Elena; Szabó, László; Apollonio, Marco

    2015-01-01

    Monitoring large carnivores is a central issue in conservation biology. The wolf (Canis lupus) is the most studied large carnivore in the world. After a massive decline and several local extinctions, mostly due to direct persecutions, wolves are now recolonizing many areas of their historical natural range. One of the main monitoring techniques is the howling survey, which is based on the wolves' tendency to use vocalisations to mark territory ownership in response to howls of unknown individuals. In most cases wolf howling sessions are useful for the localisation of the pack, but they provide only an aural estimation of the chorus size. We tested and present a new bioacoustic approach to estimate chorus size by recording wolves' replies and visualising choruses through spectrograms and spectral envelopes. To test the methodology, we compared: a) the values detected by visual inspections with the true chorus size to test for accuracy; b) the bioacoustic estimations of a sample of free-ranging wolves' replies developed by different operators to test for precision of the method; c) the aural field estimation of chorus size of a sample of free-ranging wolves' replies with the sonogram analysis of the same recordings to test for difference between methods. Visual inspection of the chorus by spectrogram and spectrum proved to be useful in determining the number of concurrent voices in a wolf chorus. Estimations of chorus size were highly correlated with the number of wolves counted in a pack, and 92 % of 29 known chorus sizes were recognized by means of bioacoustic analysis. On the basis of spectrographic evidence, it was also possible to identify up to seven concurrent vocalisations in a chorus of nine wolves. Spectral analysis of 37 free ranging wolves' replies showed a high correlation between the chorus size estimations of the different operators (92.8 %), but a low correlation with the aural estimation (59.2 %). Wolf howling monitoring technique could be

  14. Physiological and growth responses to water deficit in the bioenergy crop Miscanthus x giganteus.

    PubMed

    Ings, Jennifer; Mur, Luis A J; Robson, Paul R H; Bosch, Maurice

    2013-01-01

    High yielding perennial biomass crops of the species Miscanthus are widely recognized as one of the most promising lignocellulosic feedstocks for the production of bioenergy and bioproducts. Miscanthus is a C4 grass and thus has relatively high water use efficiency. Cultivated Miscanthus comprises primarily of a single clone, Miscanthus x giganteus, a sterile hybrid between M. sacchariflorus and M. sinensis. M. x giganteus is high yielding and expresses desirable combinations of many traits present in the two parental species types; however, it responds poorly to low water availability. To identify the physiological basis of the response to water stress in M. x giganteus and to identify potential targets for breeding improvements we characterized the physiological responses to water-deficit stress in a pot experiment. The experiment has provided valuable insights into the temporal aspects of drought-induced responses of M. x giganteus. Withholding water resulted in marked changes in plant physiology with growth-associated traits among the first affected, the most rapid response being a decline in the rate of stem elongation. A reduction in photosynthetic performance was among the second set of changes observed; indicated by a decrease in stomatal conductance followed by decreases in chlorophyll fluorescence and chlorophyll content. Measures reflecting the plant water status were among the last affected by the drought treatment. Metabolite analysis indicated that proline was a drought stress marker in M. x giganteus, metabolites in the proline synthesis pathway were more abundant when stomatal conductance decreased and dry weight accumulation ceased. The outcomes of this study in terms of drought-induced physiological changes, accompanied by a proof-of-concept metabolomics investigation, provide a platform for identifying targets for improved drought-tolerance of the Miscanthus bioenergy crop.

  15. Chorus Emission Source Spatial Scales in the Terrestrial Radiation Belts

    NASA Astrophysics Data System (ADS)

    Agapitov, O. V.; Mozer, F.; Blum, L. W.; Wygant, J. R.; Bonnell, J. W.; Shastun, V.

    2016-12-01

    The key parameters for either non-linear wave particle interactions or for the quasi-linear approach are the temporal and spatial scales of the wave source region and coherence of the oscillations in a wave package. Both of these scales (the source scale and the coherence scale) are not well-established experimentally. We investigated both of these scales using coordinated multi-point measurements from the THEMIS and Van Allen Probes missions. To accomplish these objectives, we collected long intervals of six components VLF wave measurements (16384 s-1) aboard the Van Allen Probes in the outer radiation belt during close lapping events. The spatial scales of the chorus wave source region have been found to be around 400-600 km in transverse to the background magnetic field direction for L-shells from 4 to 6. The coherence spatial and temporal scales for chorus has been found to be less/about 100 km. The results obtained from the high resolution waveform analysis have been confirmed by the THEMIS continuous measurements (FBK and FFT)

  16. Magnetic and Electric Field Polarizations of Oblique Magnetospheric Chorus Waves

    NASA Technical Reports Server (NTRS)

    Verkhoglyadova, Olga; Tsurutani, Bruce T.; Lakhina, Gurbax S.

    2012-01-01

    A theory was developed to explain the properties of the chorus magnetic and electric field components in the case of an arbitrary propagation angle. The new theory shows that a whistler wave has circularly polarized magnetic fields for oblique propagation. This theoretical result is verified by GEOTAIL observations. The wave electric field polarization plane is not orthogonal to the wave vector, and in general is highly elliptically polarized. A special case of the whistler wave called the Gendrin mode is also discussed. This will help to construct a detailed and realistic picture of wave interaction with magnetosphere electrons. It is the purpose of this innovation to study the magnetic and electric polarization properties of chorus at all frequencies, and at all angles of propagation. Even though general expressions for electromagnetic wave polarization in anisotropic plasma are derived in many textbooks, to the knowledge of the innovators, a detailed analysis for oblique whistler wave mode is lacking. Knowledge of the polarization properties is critical for theoretical calculations of resonant wave-particle interactions.

  17. Signal interactions and interference in insect choruses: singing and listening in the social environment.

    PubMed

    Greenfield, Michael D

    2015-01-01

    Acoustic insects usually sing amidst conspecifics, thereby creating a social environment-the chorus-in which individuals communicate, find mates, and avoid predation. A temporal structure may arise in a chorus because of competitive and cooperative factors that favor certain signal interactions between neighbors. This temporal structure can generate significant acoustic interference among singers that pose problems for communication, mate finding, and predator detection. Acoustic insects can reduce interference by means of selective attention to only their nearest neighbors and by alternating calls with neighbors. Alternatively, they may synchronize, allowing them to preserve call rhythm and also to listen for predators during the silent intervals between calls. Moreover, males singing in choruses may benefit from reduced per capita predation risk as well as enhanced vigilance. They may also enjoy greater per capita attractiveness to females, particularly in the case of synchronous choruses. In many cases, however, the overall temporal structure of the chorus is only an emergent property of simple, pairwise interactions between neighbors. Nonetheless, the chorus that emerges can impose significant selection pressure on the singing of those individual males. Thus, feedback loops may occur and potentially influence traits at both individual and group levels in a chorus.

  18. A Telepresence Learning Environment for Opera Singing: Distance Lessons Implementations over Internet2

    ERIC Educational Resources Information Center

    Alpiste Penalba, Francisco; Rojas-Rajs, Teresa; Lorente, Pedro; Iglesias, Francisco; Fernández, Joaquín; Monguet, Josep

    2013-01-01

    The Opera eLearning project developed a solution for opera singing distance lessons at the graduate level, using high bandwidth to deliver a quality audio and video experience that has been evaluated by singing teachers, chorus and orchestra directors, singers and other professional musicians. Prior to finding a technological model that suits the…

  19. A Telepresence Learning Environment for Opera Singing: Distance Lessons Implementations over Internet2

    ERIC Educational Resources Information Center

    Alpiste Penalba, Francisco; Rojas-Rajs, Teresa; Lorente, Pedro; Iglesias, Francisco; Fernández, Joaquín; Monguet, Josep

    2013-01-01

    The Opera eLearning project developed a solution for opera singing distance lessons at the graduate level, using high bandwidth to deliver a quality audio and video experience that has been evaluated by singing teachers, chorus and orchestra directors, singers and other professional musicians. Prior to finding a technological model that suits the…

  20. Statistical characteristics of potentially chorus-driven energetic electron precipitation from POES observations

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    In this paper, using the Polar Orbiting Environment Satellites (POES) in the year 2011, we present global distributions of energetic electron precipitation (EEP) events that may be driven by lower band chorus waves. Since the footprint of plasmapause in the ionospheric height can basically be equal to midlatitude trough minimum, it can be identified through the global total electron content map. Then we distinguish events perhaps driven by chorus waves outside the plasmapause or those driven by hiss waves inside the plasmapause. Based on the simultaneous observations of EEP in the E1 0° (>30 keV) and E2 0° (>100 keV) channels from POES satellites, a total of 4455 potentially chorus-driven events are identified. The potentially chorus-driven events are mainly distributed from midnight to noon which is similar to the distribution of lower band chorus waves. As the level of geomagnetic substorm activity increases, the occurrence rate is higher, which could be due to excitation of chorus waves associated with substorm electron injection. During higher level of substorm, a large number of events occur in lower L shells. Besides, since the magnetosphere on the dayside is compressed and strong chorus waves are limited to the region where the ratio between the plasma frequency and electron gyrofrequency is less than 5, under the strong substorm, the events on the nightside are confined to lower L shells due to smaller electron gyrofrequencies relative to those on the dayside. The occurrence rate of the events on the dayside also increases with enhancement of solar wind dynamic pressure, which suggests that the solar wind dynamic pressure can contribute to the excitation of events on the dayside. The statistics of potentially chorus-driven events are helpful to analyze the distribution of lower band chorus waves and their contributions to the loss of energetic electrons in the inner magnetosphere.

  1. Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction

    PubMed Central

    López-Bao, José Vicente; Llaneza, Luis; Fernández, Carlos; Font, Enrique

    2016-01-01

    Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus is sometimes difficult, even for experienced observers. In this study, we evaluate the usefulness of analyses of the acoustic energy distribution in chorus howls to identify the presence of pups in a chorus. We analysed 110 Iberian wolf chorus howls with known pack composition and found that the acoustic energy distribution is concentrated at higher frequencies when there are pups vocalizing. We built predictive models using acoustic energy distribution features to determine the presence of pups in a chorus, concluding that the acoustic energy distribution in chorus howls can be used to determine the presence of wolf pups in a pack. The method we outline here is objective, accurate, easily implemented, and independent of the observer's experience. These advantages are especially relevant in the case of broad scale surveys or when many observers are involved. Furthermore, the analysis of the acoustic energy distribution can be implemented for monitoring other social canids that emit chorus howls such as jackals or coyotes, provides an easy way to obtain information on ecological parameters such as reproductive success, and could be useful to study other group vocalizations. PMID:27144887

  2. Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction.

    PubMed

    Palacios, Vicente; López-Bao, José Vicente; Llaneza, Luis; Fernández, Carlos; Font, Enrique

    2016-01-01

    Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus is sometimes difficult, even for experienced observers. In this study, we evaluate the usefulness of analyses of the acoustic energy distribution in chorus howls to identify the presence of pups in a chorus. We analysed 110 Iberian wolf chorus howls with known pack composition and found that the acoustic energy distribution is concentrated at higher frequencies when there are pups vocalizing. We built predictive models using acoustic energy distribution features to determine the presence of pups in a chorus, concluding that the acoustic energy distribution in chorus howls can be used to determine the presence of wolf pups in a pack. The method we outline here is objective, accurate, easily implemented, and independent of the observer's experience. These advantages are especially relevant in the case of broad scale surveys or when many observers are involved. Furthermore, the analysis of the acoustic energy distribution can be implemented for monitoring other social canids that emit chorus howls such as jackals or coyotes, provides an easy way to obtain information on ecological parameters such as reproductive success, and could be useful to study other group vocalizations.

  3. Simultaneous observations of energetic electrons and dawnside chorus in geosynchronous orbit

    SciTech Connect

    Isenberg, P.A.; Koons, H.C.; Fennell, J.F.

    1982-03-01

    We present the first simultaneous observations of chorus activity and energetic particles from near-geosynchronous orbit by using data from the Aerospace Corporation VLF receiver and the UCSD charged particle detector on the SCATHA satellite. We find that, for the 5 days studied, June 23--27, 1979, every encounter with injected clouds of energetic electrons was accompanied by chorus activity. We conclude that dawnside chorus is generated by substorm-injected, anisotropic clouds of electrons with energies between 10 and 100 keV.

  4. Mitochondrial genome of the Christmas tree worm Spirobranchus giganteus (Annelida: Serpulidae) reveals a high substitution rate among annelids.

    PubMed

    Seixas, Victor Corrêa; Russo, Claudia Augusta de Moraes; Paiva, Paulo Cesar

    2017-03-20

    Here we describe, for the first time, the mitochondrial genome of Spirobranchus giganteus (Annelida: Serpulidae) and compare it with all available annelid mitogenomes. The entire mitogenome has 22,058bp in length and bears 12 protein-coding genes (the ATP8 gene is missing), two rRNA, and 24 tRNA genes. The nucleotide composition and GC-skew are surprisingly different from those reported for other annelids. In addition, the pairwise genetic distances between the mitogenomes of S. giganteus and other annelids are higher than the distances for all annelid taxa analyzed. This result is consistent with a faster rate of mitochondrial sequence evolution in S. giganteus, which may explain the difficulty in obtaining PCR products with the available primers. The mitochondrial gene order of S. giganteus was remarkably different not only from that of the Sedentaria lineage, which includes S. giganteus, but also from the mitochondrial gene order of other major annelid lineages. The mitogenome of S. giganteus has no repetitive motifs despite its long control region (4769bp), but genes are shorter and have a lower AT content than other members of Annelida. Finally, we show that mitochondrial gene order rearrangements can directly correlate to variations in gene length.

  5. Songs, choruses and countersinging of Kloss' gibbons (Hylobates klossii) in Siberut Island, Indonesia.

    PubMed

    Tenaza, R R

    1976-01-01

    This study evaluates the social spacing mechanism of song as it occurs in Kloss' gibbons. The study population included individuals in 13 family groups whose composition and territories were known (TENZA 1975) plus a number of others. Sonagrams illustrate individual and sexual differences in singing. Sex differences in chorusing, countersinging and other behavior related to song are described. Variations in singing or chorusing or both are related to season, time of day, sex, age, spatial factors and social factors. The adaptive functions of singing, countersinging and chorusing are discussed. It is concluded that: (1) Song is mainly for interterritorial communication between members of the same sex, (2) male-song probably also functions in mate attraction and (3) chorusing is primarily an adaptation reducing predation risk to singing gibbons.

  6. PIC Simulations of Banded Chorus Events from Van Allen Probes Observations

    NASA Astrophysics Data System (ADS)

    Fu, X.; Cowee, M.; Friedel, R. H.; Gary, S. P.; Hospodarsky, G. B.; Kletzing, C.; Liu, K.; MacDonald, E.; Reeves, G. D.; Skoug, R. M.; Winske, D.

    2013-12-01

    Banded chorus emissions are whistler waves with two bands separated by a narrow gap at 0.5ωce (ωce is the elctron gyro-frequency) in the frequency spectrum, often observed in the inner magnetosphere. The physical reason for the gap is still puzzling the space community. To better understand banded chorus generation, we identify occurrences of banded chorus in the Van Allen Probes EMFISIS data. Prameters derived from observations are used as initial conditions for our linear theory and nonlinear particle-in-cell simulations. By comparing our simulation results with electron pitch angle distributions from HOPE and wave spectra from EMFISIS, we will test some hypotheses for generation of banded chorus. LA-UR-13-26132.

  7. Chorus Wave Energy Budget Analysis in the Earth's Radiation Belts

    NASA Astrophysics Data System (ADS)

    Blancarte, J.; Agapitov, O. V.; Mozer, F.

    2016-12-01

    Whistler-mode chorus emissions are important electromagnetic waves in the Earth's magnetosphere, where they continuously scatter and accelerate electrons of the outer radiation belt, controlling radiation hazards to satellites and astronauts. Here, we present an analysis of Van Allen Probes electric and magnetic field VLF waveform data, evaluating the wave energy budget, and show that a significant fraction of the energy corresponds to very oblique waves. Such waves, with a generally much smaller (up to 10 times) magnetic power than parallel waves, typically have comparable or even larger total energy. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth's radiation belts and also provide nonlinear effects due to wave-particle interaction through the Landau resonance due to the significant electric field component parallel to the background magnetic field.

  8. Simulation of Whistler Chorus in a Compressed Dipole Field

    NASA Astrophysics Data System (ADS)

    Wu, S.; Denton, R. E.; Hudson, M.

    2015-12-01

    Earth's dipole magnetic field is constantly compressed by the solar wind and the compression is enhanced during magnetic storm. We simulate whistler chorus in a compressed dipole field using a hybrid code. The hybrid code uses the particle-in-cell technique in generalized orthogonal coordinates. In the hybrid code, a small fraction of electrons are treated as particles with anisotropic temperature that leads to the whistler instability. Other electrons are treated as a cold fluid without mass. The density of the fluid electrons is large such that the plasma frequency exceeds the electron gyro frequency. Ions serve as a fixed background. We model the compressed dipole field by adding a constant magnetic field component to the dipole field. The direction of the compressed component is the same as that of the dipole field at the equator. This model of the compressed dipole field yields a magnetic field with off-equator minima and smaller inhomogeneity than the dipole field near the equator. The distribution of hot anisotropic electrons along the magnetic field is a function of adiabatic invariants that satisfies MHD force balance. In the compressed dipole field, the hot electron anisotropy, hot electron density and plasma beta in the direction parallel to the background magnetic field are the maximum at the minimum magnetic field. In our simulation, whistler chorus are generated at the minimum magnetic field with a peak frequency in agreement with the prediction by WHAMP, a local dispersion relation solver. The waves propagate in both directions along the magnetic field. Waves that propagate to higher magnetic latitude are damped at the boundary by the artificial resistive layers, while waves that propagate to lower latitude towards the equator continue to grow.

  9. Modeling the evolution of chorus waves into plasmaspheric hiss

    NASA Astrophysics Data System (ADS)

    Bortnik, J.; Chen, L.; Li, W.; Thorne, R. M.; Horne, R. B.

    2011-08-01

    Plasmaspheric hiss (PH) is a band-limited, incoherent whistler mode emission found predominantly in the plasmasphere or high-density plasma regions in the near-Earth space environment. Since its discovery in the late 1960s, PH has been recognized as playing an important role in shaping the structure and dynamics of the Earth's electron radiation belts and creating the slot region that separates the inner and outer belts. However, the origin of PH has been a topic of intense debate for over four decades. Here we present a model for the origin of PH that involves the evolution of chorus waves into the PH spectrum. We perform extensive ray tracing using the HOTRAY code and calculate Landau damping using newly developed suprathermal flux maps from THEMIS observations, that are L and magnetic local time dependent, for both inside and outside the plasmasphere. Our results show remarkable consistency with the observed statistical characteristics of hiss, including the day/night asymmetry in wave power, frequency spectrum, geomagnetic control of PH, quasi-parallel equatorial wave normal angles, and confinement within the plasmasphere. Our model also reproduces ancillary features such as exohiss and extremely low frequency (ELF) hiss and might be related to a previously reported phenomenon called lower hybrid resonance duct trapping in the ionosphere. A detailed analysis of ray morphologies shows a separation into four distinct groups, which correspond to (1) rays that are trapped at the plasmapause, (2) PH rays, (3) ELF hiss rays, and (4) rays that represent the bulk of the chorus ray power.

  10. Evolution of chorus emissions into plasmaspheric hiss observed by Van Allen Probes

    DOE PAGES

    Zhou, Qinghua; Xiao, Fuliang; Yang, Chang; ...

    2016-05-09

    The two classes of whistler mode waves (chorus and hiss) play different roles in the dynamics of radiation belt energetic electrons. Chorus can efficiently accelerate energetic electrons, and hiss is responsible for the loss of energetic electrons. Previous studies have proposed that chorus is the source of plasmaspheric hiss, but this still requires an observational confirmation because the previously observed chorus and hiss emissions were not in the same frequency range in the same time. In this paper, we report simultaneous observations form Van Allen Probes that chorus and hiss emissions occurred in the same range ~300–1500 Hz with themore » peak wave power density about 10-5 nT2/Hz during a weak storm on 3 July 2014. Chorus emissions propagate in a broad region outside the plasmapause. Meanwhile, hiss emissions are confined inside the plasmasphere, with a higher intensity and a broader area at a lower frequency. A sum of bi-Maxwellian distribution is used to model the observed anisotropic electron distributions and to evaluate the instability of waves. A three-dimensional ray tracing simulation shows that a portion of chorus emission outside the plasmasphere can propagate into the plasmasphere and evolve into plasmaspheric hiss. Moreover, hiss waves below 1 kHz are more intense and propagate over a broader area than those above 1 kHz, consistent with the observation. Finally, the current results can explain distributions of the observed hiss emission and provide a further support for the mechanism of evolution of chorus into hiss emissions.« less

  11. A simulation study of the propagation of whistler-mode chorus in the Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Katoh, Yuto

    2014-12-01

    We study the propagation of whistler-mode chorus in the magnetosphere by a spatially two-dimensional simulation code in the dipole coordinates. We set the simulation system so as to assume the outside of the plasmapause, corresponding to the radial distance from 3.9 to 4.1 R E in the equatorial plane and the latitudinal range from -15° to +15°, where R E is the Earth's radius. We assume a model chorus element propagating northward from the magnetic equator of the field line at L=4 with a rising tone from 0.2 to 0.7 Ω e0 in the time scale of 5,000 [InlineEquation not available: see fulltext.], where Ω e0 is the electron gyrofrequency at the magnetic equator. For the initial density distribution of cold electrons, we assume three types of initial conditions in the outside of the plasmapause: without a duct (run 1), a density enhancement duct (run 2), and a density decrease duct (run 3). In run 1, the simulation result reveals that whistler-mode waves of the different wave frequencies propagate in the different ray path in the region away from the magnetic equator. In runs 2 and 3, the model chorus element propagates inside the assumed duct with changing wave normal angle. The simulation results show the different propagation properties of the chorus element in runs 2 and 3 and reveal that resultant wave spectra observed along the field line are different between the density enhancement and density decrease duct cases. The spectral modification of chorus by the propagation effect should play a significant role in the interactions between chorus and energetic electrons in the magnetosphere, particularly in the region away from the equator. The present study clarifies that the variation of propagation properties of chorus should be taken into account for the thorough understanding of resonant interactions of chorus with energetic electrons in the inner magnetosphere.

  12. Evolution of chorus emissions into plasmaspheric hiss observed by Van Allen Probes

    SciTech Connect

    Zhou, Qinghua; Xiao, Fuliang; Yang, Chang; Liu, Si; He, Yihua; Wygant, J. R.; Baker, D. N.; Spence, H. E.; Reeves, Geoffrey D.; Funsten, Herbert O.

    2016-05-09

    The two classes of whistler mode waves (chorus and hiss) play different roles in the dynamics of radiation belt energetic electrons. Chorus can efficiently accelerate energetic electrons, and hiss is responsible for the loss of energetic electrons. Previous studies have proposed that chorus is the source of plasmaspheric hiss, but this still requires an observational confirmation because the previously observed chorus and hiss emissions were not in the same frequency range in the same time. In this paper, we report simultaneous observations form Van Allen Probes that chorus and hiss emissions occurred in the same range ~300–1500 Hz with the peak wave power density about 10-5 nT2/Hz during a weak storm on 3 July 2014. Chorus emissions propagate in a broad region outside the plasmapause. Meanwhile, hiss emissions are confined inside the plasmasphere, with a higher intensity and a broader area at a lower frequency. A sum of bi-Maxwellian distribution is used to model the observed anisotropic electron distributions and to evaluate the instability of waves. A three-dimensional ray tracing simulation shows that a portion of chorus emission outside the plasmasphere can propagate into the plasmasphere and evolve into plasmaspheric hiss. Moreover, hiss waves below 1 kHz are more intense and propagate over a broader area than those above 1 kHz, consistent with the observation. Finally, the current results can explain distributions of the observed hiss emission and provide a further support for the mechanism of evolution of chorus into hiss emissions.

  13. Evolution of chorus emissions into plasmaspheric hiss observed by Van Allen Probes

    SciTech Connect

    Zhou, Qinghua; Xiao, Fuliang; Yang, Chang; Liu, Si; He, Yihua; Wygant, J. R.; Baker, D. N.; Spence, H. E.; Reeves, Geoffrey D.; Funsten, Herbert O.

    2016-05-09

    The two classes of whistler mode waves (chorus and hiss) play different roles in the dynamics of radiation belt energetic electrons. Chorus can efficiently accelerate energetic electrons, and hiss is responsible for the loss of energetic electrons. Previous studies have proposed that chorus is the source of plasmaspheric hiss, but this still requires an observational confirmation because the previously observed chorus and hiss emissions were not in the same frequency range in the same time. In this paper, we report simultaneous observations form Van Allen Probes that chorus and hiss emissions occurred in the same range ~300–1500 Hz with the peak wave power density about 10-5 nT2/Hz during a weak storm on 3 July 2014. Chorus emissions propagate in a broad region outside the plasmapause. Meanwhile, hiss emissions are confined inside the plasmasphere, with a higher intensity and a broader area at a lower frequency. A sum of bi-Maxwellian distribution is used to model the observed anisotropic electron distributions and to evaluate the instability of waves. A three-dimensional ray tracing simulation shows that a portion of chorus emission outside the plasmasphere can propagate into the plasmasphere and evolve into plasmaspheric hiss. Moreover, hiss waves below 1 kHz are more intense and propagate over a broader area than those above 1 kHz, consistent with the observation. Finally, the current results can explain distributions of the observed hiss emission and provide a further support for the mechanism of evolution of chorus into hiss emissions.

  14. Evening choruses in the Perth Canyon and their potential link with Myctophidae fishes.

    PubMed

    McCauley, Robert D; Cato, Douglas H

    2016-10-01

    An evening chorus centered at near 2.2 kHz was detected across the years 2000 to 2014 from seabed receivers in 430-490 m depth overlooking the Perth Canyon, Western Australia. The chorus reached a maximum level typically 2.1 h post-sunset and normally ran for 2.1 h (between 3 dB down points). It was present at lower levels across most of the hours of darkness. Maximum chorus spectrum levels were 74-76 dB re 1 μPa(2)/Hz in the 2 kHz 1/3 octave band, averaging 6-12 dB and up to 30 dB greater than pre-sunset levels. The chorus displayed highest levels over April to August each year with up to 10 dB differences between seasons. The spatial extent of the chorus was not determined but exceeded the sampling range of 13-15 km offshore from the 300 m depth contour and 33 km along the 300 m depth contour. The chorus comprised short damped pulses. The most likely chorus source is considered to be fishes of the family Myctophidae foraging in the water column. The large chorus spatial extent and its apparent correlation with regions of high productivity suggest it may act as an acoustic beacon to marine fauna indicating regions of high biomass.

  15. Plasma biochemistry and hematologic values for wild-caught flying foxes (Pteropus giganteus) in India.

    PubMed

    McLaughlin, Amanda B; Epstein, Jonathan H; Prakash, Vibhu; Smith, Craig S; Daszak, Peter; Field, Hume E; Cunningham, Andrew A

    2007-09-01

    Although bats of the genus Pteropus are important ecologically as pollinators and natural hosts for zoonotic pathogens, little is known about their basic physiology. Hematology and plasma biochemistries were determined from wild-caught flying foxes (Pteropus giganteus) in northern India (n=41). Mean lymphocyte differential count was higher for juveniles than adults. Mean platelet count was lower than previously reported. No hemoparasites were observed. No differences were observed between plasma biochemistry values of male and female bats, juveniles and adults, or lactating and nonlactating females. Variation in aspartate aminotransferase (AST) was seen based on body condition score. Blood urea nitrogen and cholesterol concentrations were lower in P. giganteus than other mammalian groups, but were consistent with those reported from other Pteropus species. Alanine aminotransferase and AST concentrations were higher than those reported for Pteropus vampyrus, a closely related species. This study provides basic physiologic information that can be used in future health and disease studies of Indian flying foxes.

  16. Lipid constituents of the edible mushroom, Pleurotus giganteus demonstrate anti-Candida activity.

    PubMed

    Phan, Chia-Wei; Lee, Guan-Serm; Macreadie, Ian G; Malek, Sri Nurestri Abd; Pamela, David; Sabaratnam, Vikineswary

    2013-12-01

    Different solvent extracts of Pleurotus giganteus fruiting bodies were tested for antifungal activities against Candida species responsible for human infections. The lipids extracted from the ethyl acetate fraction significantly inhibited the growth of all the Candida species tested. Analysis by GC/MS revealed lipid components such as fatty acids, fatty acid methyl esters, ergosterol, and ergosterol derivatives. The sample with high amounts of fatty acid methyl esters was the most effective antifungal agent. The samples were not cytotoxic to a mammalian cell line, mouse embryonic fibroblasts BALB/c 3T3 clone A31. To our knowledge, this is the first report of antifungal activity of the lipid components of Pleurotus giganteus against Candida species.

  17. The complete mitochondrial genome of the eastern grey kangaroo (Macropus giganteus).

    PubMed

    Dodt, William G; McComish, Bennet J; Nilsson, Maria A; Gibb, Gillian C; Penny, David; Phillips, Matthew J

    2016-01-01

    We present the complete mitochondrial genome (accession number: LK995454) of an iconic Australian species, the eastern grey kangaroo (Macropus giganteus). The mitogenomic organization is consistent with other marsupials, encoding 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, an origin of light strand replication and a control region or D-loop. No repetitive sequences were detected in the control region. The M. giganteus mitogenome exemplifies a combination of tRNA gene order and structural peculiarities that appear to be unique to marsupials. We present a maximum likelihood phylogeny based on complete mitochondrial protein and RNA coding sequences that confirms the phylogenetic position of the grey kangaroo among macropodids.

  18. Phonotaxis to male's calls embedded within a chorus by female gray treefrogs, Hyla versicolor.

    PubMed

    Christie, Kevin; Schul, Johannes; Feng, Albert S

    2010-08-01

    During the reproductive season, male Hyla versicolor produce advertisement calls to attract females. Females exhibit phonotaxis and approach the individual callers, resulting in amplexus. For frogs that call from dense choruses, the extent to which and the range from which a male's advertisement call within a chorus can be heard by a receptive female leading to phonotaxis is unclear. We investigated females' responses to natural choruses in the field and found that they were attracted and showed directed orientation to breeding choruses at distances up to 100 m. To assess the role of acoustic cues in the directed orientation, we conducted acoustic playback experiments in the laboratory using conspecific call and noise as stimuli, as well as chorus sounds (that contained calls from a focal male) recorded at various distances, all played at naturalistic intensities. Using two response metrics (females' normalized response times and their phonotaxis trajectories) we found that, unlike the field experiments, females oriented and were attracted to chorus sounds from 1 to 32 m only, but not from >32 m, or to band-limited noise. Possible reasons for the observed difference in phonotaxis behavior in the two experimental conditions were discussed.

  19. The chorus environment and the shape of communication systems in frogs

    NASA Astrophysics Data System (ADS)

    Marshall, Vince

    2003-04-01

    Many species of frogs breed in dense and structurally complex aggregations of calling males termed choruses. Females entering a chorus are faced with the tasks of recognizing and locating mates on the basis of their advertisement calls. The chorus environment poses particular challenges for communication as signalers and receivers will face high levels of background noise and interference between signals. For females, such conditions may decrease the efficiency of communication, with the consequences of increasing the time required to find a mate or errors in mate choice. For males, it will give rise to intense competition for the attention of females. Additionally, the chorus environment for a species is not static, and will vary over both spatial and temporal scales. This complex and dynamic environment has shaped the signals and signaling behaviors of frogs in sometimes surprising ways. In this talk, some of the implications of the chorus environment for both receivers and signalers is discussed. In particular, examples from North American hylid frogs are drawn upon and research on the role of signal timing in influencing the responses of females and plasticity in aggressive behavior between neighbors in choruses are discussed.

  20. Excitation of dayside chorus waves due to magnetic field line compression in response to interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Li, Wen; Thorne, Richard M.; Bortnik, Jacob; Ma, Qianli; An, Xin; Zhang, Xiao-jia; Angelopoulos, Vassilis; Ni, Binbin; Gu, Xudong; Fu, Song; Zhao, Zhengyu

    2015-10-01

    The excitation of magnetospheric whistler-mode chorus in response to interplanetary (IP) shocks is investigated using wave data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. As an example, we show a typical chorus wave excitation following an IP shock event that was observed by THEMIS in the postnoon sector near the magnetopause on 3 August 2010. We then analyze characteristic changes during this event and perform a survey of similar events during the period 2008-2014 using the THEMIS and OMNI data set. Our statistical analysis demonstrates that the chorus wave excitation/intensification in response to IP shocks occurs only at high L shells (L > 8) on the dayside. We analyzed the variations of magnetic curvature following the arrival of the IP shock and found that IP shocks lead to more homogeneous background magnetic field configurations in the near-equatorial dayside magnetosphere; and therefore, the threshold of nonlinear chorus wave growth is likely to be reduced, favoring chorus wave generation. Our results provide the observational evidence to support the concept that the geomagnetic field line configuration plays a key role in the excitation of dayside chorus.

  1. Correlations between chorus properties and electron velocity distributions: Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Fu, X.; Cowee, M.; Gary, S. P.; Liu, K.; Min, K.; Winske, D.

    2014-12-01

    Magnetospheric chorus consists of whistler waves driven unstable by anisotropicelectron velocity distributions. A gap in the power spectrum of chorus at a fre-quency close to half the electron cyclotron frequency (Ωe/2) are often observedso that chorus can be categorized into four types accordingly: banded chorus(with two bands in the spectrum separated by Ωe/2), lower band only (withonly one band below Ωe/2), upper band only (with only one band above Ωe/2)and broadband (with only one band including Ωe/2). Here we present a studyto correlate chorus properties with electron velocity distributions based on thehypothesis that each band of chorus is excited by an anisotropic electron com-ponent. On Jan 14 2013, Van Allen Probes satellite A measured strong chorusactivity, and all four types were observed. We analyze HOPE and EMFISIS dataand show that there is a good correlation between the observed wave frequencyand propagation direction and the predictions of kinetic linear dispersion theoryusing electron component densities and temperatures obtained by fitting HOPEdata to a multi-component bi-Maxwellian distribution function. However, thetemperature anisotropies observed by HOPE are usually close to the instabil-ity threshold and therefore it is not possible at this point to predict whether acertain band can be excited based on measured electron velocity distributions.LA-UR-14-26177.

  2. Functional morphology of the hindleg in two kangaroos Macropus giganteus and Aepyprymnus rufescens.

    PubMed

    Lodder, M A

    1991-01-01

    In this study the structures in the hindleg of the kangaroo which are potentially available for jumping were examined. Specimens of two species, Macropus giganteus and Aepyprymnus rufescens, were examined and are described and compared. The basic pattern of the jump of the two species is similar. This is reflected anatomically by the fact that in both species the extensors of the hip, knee and ankle as a percentage of the total weight of the hindleg are greater than the flexors of the same joints. An additional similarity is that the biceps femoris and adductor magnus have the greatest share in the weight of the hip extensors. Furthermore the estimated total force of the hip, knee and ankle extensors and total moment of the hip and ankle extensors are always greater than the flexors of the same joints. However, the percentage of the hip and knee extensors, the absolute forces and moments of both the extensors and flexors and the range of movement especially of the hip and knee are always greater in M. giganteus than in A. rufescens. As well as these differences, the long tibia and the position of the knee in view of the hip may be important factors for the longer jump achieved by M. giganteus. In comparison A. rufescens has a anatomical construction which seems to be a compromise between walking and jumping.

  3. Phytoremediation potential of Miscanthus × giganteus and Spartina pectinata in soil contaminated with heavy metals.

    PubMed

    Korzeniowska, Jolanta; Stanislawska-Glubiak, Ewa

    2015-08-01

    The aim of this work was to assess the suitability of Miscanthus × giganteus and Spartina pectinata link to Cu, Ni, and Zn phytoremediation. A 2-year microplot experiment with the tested grasses growing on metal-contaminated soil was carried out. Microplots with cement borders, measuring 1 × 1 × 1m, were filled with Haplic Luvisols soil. Simulated soil contamination with Cu, Ni, and Zn was introduced in the following doses in mg kg(-1): 0-no metals, Cu1-100, Cu2-200, Cu3-400, Ni1-60, Ni2-100, Ni3-240, Zn1-300, Zn2-600, and Zn3-1200. The phytoremediation potential of grasses was evaluated using a tolerance index (TI), bioaccumulation factor (BF), bioconcentration factor (BCF), and translocation factor (TF). S. pectinata showed a higher tolerance to soil contamination with Cu, Ni, and Zn compared to M. × giganteus. S. pectinata was found to have a high suitability for phytostabilization of Zn and lower suitability of Cu and Ni. M. × giganteus had a lower phytostabilization potential than S. pectinata. The suitability of both grasses for Zn phytoextraction depended on the age of the plants. Both grasses were not suitable for Cu and Ni phytoextraction. The research showed that one-season studies were not valuable for fully assessing the phytoremediation potential of perennial plants.

  4. Coral preference behaviour by planktotrophic larvae of Spirobranchus giganteus corniculatus (Serpulidae: Polychaeta)

    NASA Astrophysics Data System (ADS)

    Marsden, Joan R.

    1987-10-01

    Planktonic larvae of the serpulid polychaete Spirobranchus giganteus, an obligate associate of live coral, were tested for preferences for materials diffusing from natural substrates. Choices offered were Acropora prolifera, a very abundant coral on the Heron Island reef flat; Palauastraea ramosa, a less abundant coral, dead coral rubble and a glass tube as a control. Larval life is approximately 12 days. The larvae tested were 1 4 days old. Adults of S. giganteus occur commonly on A. prolifera and much less frequently on P. ramosa. Experiments were designed to prevent contact between larvae and substrate. Larvae preferred A. prolifera over P. ramosa, rubble and the control. There was no preference expressed between the control and P. ramosa or the control and rubble. A preference by young S. giganteus larvae for a substance diffusing from coral, acting together with a known positive phototaxis, may be adaptive in that it may help to maintain larvae in surface waters over the reef and in the vicinity of a specific coral until they are old enough to settle.

  5. Effect of fire on a monodominant floating mat of Cyperus giganteus Vahl in a neotropical wetland.

    PubMed

    Rocha, M; Santos Júnior, C C; Damasceno-Júnior, G A; Pott, V J; Pott, A

    2015-01-01

    The rhizomatous Cyperus giganteus, abundant in the Pantanal wetland, can dominate extense floodable areas as monodominant communities. The Jacadigo lake has a large area of C. giganteus, where we performed an evaluation on community structure during two months in 2010, before it was hit by a wildfire which top-killed the vegetation, compared to ten months post-fire. We utilized 40 plots of 1m × 1m, along permanent trails, assessing two strata: the upper, near the inflorescence of adult plants, and the lower, close to the water level. Our results show that fire does not affect dominance of C. giganteus, as it maintained the same cover as before fire; species richness is not much altered either - 28 before fire and 34 thereafter. Fire changed the floristic composition, due to the annual variation of species and the ability of some plants to colonize gaps and to regrow after fire from underground organs and seeds. The stratification of the vegetation with characteristic species of upper and lower strata was similar after fire.

  6. Plant and soil effects on bacterial communities associated with Miscanthus  ×  giganteus rhizosphere and rhizomes

    DOE PAGES

    Li, Dongfang; Voigt, Thomas B.; Kent, Angela D.

    2015-02-11

    Here, bacterial assemblages, especially diazotroph assemblages residing in the rhizomes and the rhizosphere soil of Miscanthus × giganteus, contribute to plant growth and nitrogen use efficiency. However, the composition of these microbial communities has not been adequately explored nor have the potential ecological drivers for these communities been sufficiently studied. This knowledge is needed for understanding and potentially improving M. × giganteus – microbe interactions, and further enhancing sustainability of M. × giganteus production. In this study, cultivated M. × giganteus from four sites in Illinois, Kentucky, Nebraska, and New Jersey were collected to examine the relative influences of soilmore » conditions and plant compartments on assembly of the M. × giganteus-associated microbiome. Automated ribosomal intergenic spacer (ARISA) and terminal restriction fragment length polymorphism (T-RFLP) targeting the nifH gene were applied to examine the total bacterial communities and diazotroph assemblages that reside in the rhizomes and the rhizosphere. Distinct microbial assemblages were detected in the endophytic and rhizosphere compartments. Site soil conditions had strong correlation with both total bacterial and diazotroph assemblages, but in different ways. Nitrogen treatments showed no significant effect on the composition of diazotroph assemblages in most sites. Endophytic compartments of different M. × giganteus plants tended to harbor similar microbial communities across all sites, whereas the rhizosphere soil of different plant tended to harbor diverse microbial assemblages that were distinct among sites. These observations offer insight into better understanding of the associative interactions between M. × giganteus and diazotrophs, and how this relationship is influenced by agronomic and edaphic factors.« less

  7. Generation condition of the Upper-band and Lower-band chorus emissions in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Habagishi, T.; Yagitani, S.; Omura, Y.; Kojima, H.

    2013-12-01

    In the present study, chorus emissions have been analyzed on the basis of the nonlinear growth theory [1] in the Earth's magnetosphere. A rising-tone chorus emission is initially generated continuously in the frequency range from 0.1 to 0.7 fce0, where fce0 is the gyrofrequency in the generation region. Because of the nonlinear damping mechanism [2] the rising-tone chorus is separated into upper and lower bands at half the local gyrofrequency for the quasi-parallel propagation toward higher latitude (i.e. toward larger gyrofrequencies). Thus the lower cutoff of the upper-band chorus indicates half-gyrofrequency at the observational point (1/2 fce), whereas the upper cutoff of the lower-band chorus indicates half the gyrofrequency in the generation region (1/2fce0). We found an observational evidence of such characteristics of upper-band and lower-band chorus observed by the wave form capture (WFC) and the sweep frequency analyzer (SFA) onboard Geotail [3]. Mainly ';'lower-band-only chorus'' (only the lower-band emission exists) is observed and occasionally ';'dual-band chorus'' (both the upper-band and the lower-band emissions) is observed by Geotail. In this study, we statistically analyze the difference between the lower-band-only chorus and the dual-band chorus, using the SFA data obtained during October, 1992 and August, 2011. It has been confirmed that the dual-band chorus is generated because of the nonlinear damping at half the local gyrofrequency during the propagation. When the dual-band chorus propagates toward higher latitudes with its the upper-band part completely damped at half the local gyrofrequencies, the dual-band chorus becomes the lower-band-only chorus. We assume that the upper cutoff frequency of the lower-band chorus equals to the half-gyrofrequency in the generation region. When 0.7 fce0 (i.e. upper limit frequency of the chorus generation) is higher than local 1/2 fce, the dual-band chorus is possibly observed because the higher

  8. Statistical study of chorus wave distributions in the inner magnetosphere using Ae and solar wind parameters

    NASA Astrophysics Data System (ADS)

    Aryan, Homayon; Yearby, Keith; Balikhin, Michael; Agapitov, Oleksiy; Krasnoselskikh, Vladimir; Boynton, Richard

    2014-08-01

    Energetic electrons within the Earth's radiation belts represent a serious hazard to geostationary satellites. The interactions of electrons with chorus waves play an important role in both the acceleration and loss of radiation belt electrons. The common approach is to present model wave distributions in the inner magnetosphere under different values of geomagnetic activity as expressed by the geomagnetic indices. However, it has been shown that only around 50% of geomagnetic storms increase flux of relativistic electrons at geostationary orbit while 20% causes a decrease and the remaining 30% has relatively no effect. This emphasizes the importance of including solar wind parameters such as bulk velocity (V), density (n), flow pressure (P), and the vertical interplanetary magnetic field component (Bz) that are known to be predominately effective in the control of high energy fluxes at the geostationary orbit. Therefore, in the present study the set of parameters of the wave distributions is expanded to include the solar wind parameters in addition to the geomagnetic activity. The present study examines almost 4 years (1 January 2004 to 29 September 2007) of Spatio-Temporal Analysis of Field Fluctuation data from Double Star TC1 combined with geomagnetic indices and solar wind parameters from OMNI database in order to present a comprehensive model of wave magnetic field intensities for the chorus waves as a function of magnetic local time, L shell (L), magnetic latitude (λm), geomagnetic activity, and solar wind parameters. Generally, the results indicate that the intensity of chorus emission is not only dependent upon geomagnetic activity but also dependent on solar wind parameters with velocity and southward interplanetary magnetic field Bs (Bz < 0), evidently the most influential solar wind parameters. The largest peak chorus intensities in the order of 50 pT are observed during active conditions, high solar wind velocities, low solar wind densities, high

  9. Effects of Miscanthus × giganteus and Wheat Straw on Behavior, Survival, and Growth of Alphitobius diaperinus (Coleoptera: Tenebrionidae).

    PubMed

    Renkema, Justin M; Haverkamp, Samantha; DeBruyn, Jake; Dam, Al; Hager, Heather A

    2016-04-22

    The lesser mealworm, Alphitobius diaperinus (Panzer), damages poultry barns, vectors poultry diseases, inhibits poultry weight gain, and consumes poultry feed. Management of the pest is a challenge because of its resistance to several insecticides, difficulty in treating infestations that can be concealed in locations within barns, and the high populations that occur around spilled poultry feed. However, few A. diaperinus were observed in Miscanthus × giganteus straw in a case where it was used as an alternative bedding material in open-floor poultry production in Ontario. To investigate this, we tested the effects of Miscanthus × giganteus and wheat straw on A. diaperinus behavior, survival, and growth in laboratory experiments. In these experiments, adult beetles preferred to inhabit wheat straw, whereas late-instar larvae preferred Miscanthus × giganteus As a result, more adult beetles emerged from pupae in Miscanthus × giganteus than in wheat, but there was no difference in emerged beetle weight. Early-instar larvae survived and increased in weight at similar rates in both straw types. Thus, while adult A. diaperinus strongly preferred wheat straw given a choice, late-instar preference and pupae emergence suggest that Miscanthus × giganteus may not be useful for suppressing A. diaperinus populations.

  10. An increase in expression of Pyruvate Pi Dikinase and its high activation energy correspond to cold-tolerant C4 photosynthesis of Miscanthus x giganteus

    USDA-ARS?s Scientific Manuscript database

    Miscanthus x giganteus is exceptional among C4 plants in its ability to produce leaves and photosynthesize at low temperature. While the most cold-adapted Zea mays lines show loss of photosynthetic capacity when transferred to 14 oC, M. x giganteus shows no loss and can continue photosynthesis down ...

  11. An increase in expression of Pyruvate Pi Dikinase and its high activation energy correspond to cold-tolerant C4 photosynthesis of Miscanthus x giganteus

    USDA-ARS?s Scientific Manuscript database

    Miscanthus x giganteus is exceptional among C4 plants in its ability to produce leaves and photosynthesize at low temperature. While the most cold-adapted Zea mays lines show loss of photosynthetic capacity when transferred to 14 deg C, M. x giganteus shows no loss and can continue photosynthesis do...

  12. Van Allen Probes observations of whistler-mode chorus with long-lived oscillating tones

    NASA Astrophysics Data System (ADS)

    Gao, Zhonglei; Su, Zhenpeng; Chen, Lunjin; Zheng, Huinan; Wang, Yuming; Wang, Shui

    2017-06-01

    Whistler-mode chorus plays an important role in the radiation belt electron dynamics. In the frequency-time spectrogram, chorus often appears as a hiss-like band and/or a series of short-lived (up to ˜1 s) discrete elements. Here we present some rarely reported chorus emissions with long-lived (up to 25 s) oscillating tones observed by the Van Allen Probes in the dayside (MLT ˜9-14) midlatitude (|MLAT|>15°) region. An oscillating tone can behave either regularly or irregularly and can even transform into a nearly constant tone (with a relatively narrow frequency sweep range). We suggest that these highly coherent oscillating tones were generated naturally rather than being related to some artificial VLF transmitters. Possible scenarios for the generation of the oscillating tone chorus are as follows: (1) being nonlinearly triggered by the accompanying hiss-like bands or (2) being caused by the modulation of the wave source. The details of the generation and evolution of such a long-lived oscillating tone chorus need to be investigated both theoretically and experimentally in the future.

  13. Chorus whistler wave source scales as determined from multipoint Van Allen Probe measurements

    NASA Astrophysics Data System (ADS)

    Agapitov, Oleksiy; Mozer, Forrest; Blum, Lauren; Bonnell, John; Wygant, John

    2017-04-01

    Whistler-mode chorus waves are a particularly important process in outer radiation belt dynamics due to their key role in controlling the acceleration and scattering of electrons over a very wide energy range. The key parameters for both nonlinear and quasi-linear treatment of wave-particle interactions are the temporal and spatial scales of the wave source region and coherence of the wave field perturbations. Both of these scales, the source scale and the coherence scale, are not well-established experimentally, mostly because of a lack of VLF waveform data. We present an unprecedentedly long interval of coordinated VLF waveform measurements (sampled at 16384 s-1) aboard the two Van Allen Probes spacecraft. The cross spacecraft distance varied from about 100 up to 5000 km. Using time-domain correlation techniques, the chorus source regions have been determined to be about 450-550 km for upper band chorus waves with amplitude less than 100 pT and up to 1000 km for larger amplitude lower band chorus waves. The ratio between wave amplitudes measured on the two spacecraft is also examined and reveals that the wave amplitude distribution within a region of chorus element generation can be well approximated by the Gaussian with the characteristic distance r0 around 300 km. This work was supported by the JHU/APL contract 922613 (RBSP-EFW) and NASA Grant NNX16AF85G.

  14. On the origin of falling-tone chorus elements in Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Breuillard, H.; Agapitov, O.; Artemyev, A.; Krasnoselskikh, V.; Le Contel, O.; Cully, C. M.; Angelopoulos, V.; Zaliznyak, Y.; Rolland, G.

    2014-12-01

    Generation of extremely/very low frequency (ELF/VLF) chorus waves in Earth's inner magnetosphere has received increased attention recently because of their significance for radiation belt dynamics. Though past theoretical and numerical models have demonstrated how rising-tone chorus elements are produced, falling-tone chorus element generation has yet to be explained. Our new model proposes that weak-amplitude falling-tone chorus elements can be generated by magnetospheric reflection of rising-tone elements. Using ray tracing in a realistic plasma model of the inner magnetosphere, we demonstrate that rising-tone elements originating at the magnetic equator propagate to higher latitudes. Upon reflection there, they propagate to lower L-shells and turn into oblique falling tones of reduced power, frequency, and bandwidth relative to their progenitor rising tones. Our results are in good agreement with comprehensive statistical studies of such waves, notably using magnetic field measurements from THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft. Thus, we conclude that the proposed mechanism can be responsible for the generation of weak-amplitude falling-tone chorus emissions.

  15. Why do Chinese alligators (Alligator sinensis) form bellowing choruses: a playback approach.

    PubMed

    Wang, Xianyan; Wang, Ding; Zhang, Song; Wang, Chaolin; Wang, Renping; Wu, Xiaobing

    2009-10-01

    Crocodilians are quite vocal relative to other reptile groups, and the alligators are among the most vocal of the crocodilians. The Chinese alligator, Alligator sinensis, is usually solitary but engages in bellowing choruses in certain waters during the mating season. This paper reports the organization of Chinese alligator's bellowing choruses based upon field observations and playback experiments. Alligators of both genders engaged in the choruses, remaining immobile throughout and inclining toward bellowing synchronously (i.e., starting and finishing at about the same time). The choruses lasted about 10 min with abrupt onset and offset. Moreover, playback experiments revealed that both male and female alligators responded equally to bellowing stimuli from the same and opposite sexes and that none of the tested alligators approached the loudspeaker in spite of playback of male or female stimuli. These suggest that Chinese alligators may not bellow to compete for or attract mates during the choruses. Instead, when their ecological behaviors, namely, dispersed inhabitation, multi-copulation, restricted mating season, etc., are considered, we hypothesize that they may synchronize bellows to enhance group detectability for assembling individuals into certain waters for subsequent copulations.

  16. Rhythm Generation and Rhythm Perception in Insects: The Evolution of Synchronous Choruses

    PubMed Central

    Hartbauer, Manfred; Römer, Heiner

    2016-01-01

    Insect sounds dominate the acoustic environment in many natural habitats such as rainforests or meadows on a warm summer day. Among acoustic insects, usually males are the calling sex; they generate signals that transmit information about the species-identity, sex, location, or even sender quality to conspecific receivers. Males of some insect species generate signals at distinct time intervals, and other males adjust their own rhythm relative to that of their conspecific neighbors, which leads to fascinating acoustic group displays. Although signal timing in a chorus can have important consequences for the calling energetics, reproductive success and predation risk of individuals, still little is known about the selective forces that favor the evolution of insect choruses. Here, we review recent advances in our understanding of the neuronal network responsible for acoustic pattern generation of a signaler, and pattern recognition in receivers. We also describe different proximate mechanisms that facilitate the synchronous generation of signals in a chorus and provide examples of suggested hypotheses to explain the evolution of chorus synchrony in insects. Some hypotheses are related to sexual selection and inter-male cooperation or competition, whereas others refer to the selection pressure exerted by natural predators. In this article, we summarize the results of studies that address chorus synchrony in the tropical katydid Mecopoda elongata, where some males persistently signal as followers although this reduces their mating success. PMID:27303257

  17. Global model of low-frequency chorus (fLHR

    PubMed Central

    Meredith, Nigel P; Horne, Richard B; Li, Wen; Thorne, Richard M; Sicard-Piet, Angélica

    2014-01-01

    Whistler mode chorus is an important magnetospheric emission, playing a dual role in the acceleration and loss of relativistic electrons in the Earth's outer radiation belt. Chorus is typically generated in the equatorial region in the frequency range 0.1–0.8 fce, where fce is the local electron gyrofrequency. However, as the waves propagate to higher latitudes, significant wave power can occur at frequencies below 0.1fce. Since this wave power is largely omitted in current radiation belt models, we construct a global model of low-frequency chorus, fLHRchorus is strongest, with an average intensity of 200 pT2, in the prenoon sector during active conditions at midlatitudes (20°<|λm|<50°) from 4chorus wave power will contribute to the acceleration and loss of relativistic electrons and should be taken into account in radiation belt models. Key Points Strong chorus waves can extend below 0.1 times local electron gyrofrequency Low frequency chorus strongest at mid-latitudes in pre-noon sector for L*=4 to 8 Low frequency chorus should be included in radiation belt models PMID:25821274

  18. Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure

    NASA Astrophysics Data System (ADS)

    Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.; Wygant, J. R.

    2017-01-01

    Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. Here on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss.

  19. Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure

    DOE PAGES

    Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; ...

    2016-12-29

    Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. In this paper, on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Finally, following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration withmore » the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss.« less

  20. Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure

    SciTech Connect

    Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.; Wygant, J. R.

    2016-12-29

    Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. In this paper, on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Finally, following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration with the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss.

  1. Propagation features of chorus-like emissions and their satellite observations

    NASA Astrophysics Data System (ADS)

    Chum, J.; Jiricek, F.; Smilauer, J.; Shklyar, D.

    2003-04-01

    After a brief introduction to chorus-like emission, we present an overview of MAGION 5 satellite observations of these emissions in the inner magnetosphere of the Earth. From the extensive VLF data recorded onboard the MAGION 5 satellite, we show examples of different types of discrete elements, representing rising and falling tones, and discuss their spectral properties such as the bandwidth and the characteristic frequency as compared to the equatorial electron gyrofrequency. Next we focus on the analysis of a possibility of satellite observation of discrete elements assuming nonducted wave propagation from the source. As for the characteristic dimension of the generation region, we apply the figures obtained from the correlation analysis of chorus emission recorded by four satellites in CLUSTER experiment. We conclude that different frequencies in the chorus element should be emitted in a certain span of wave normal angles, so that the whole element could be observed far from the generation region.

  2. Observation and Simulation of Chorus Waves Generation at the Gradients of Magnetic Holes

    NASA Astrophysics Data System (ADS)

    Ahmadi, N.; Argall, M. R.; Paulson, K. W.; Ergun, R.; Wilder, F. D.; Germaschewski, K.; Khotyaintsev, Y. V.; Torbert, R. B.; Russell, C. T.; Strangeway, R. J.; Magnes, W.; Le Contel, O.; Giles, B. L.

    2016-12-01

    The Magnetospheric Multiscale (MMS) mission observed chorus waves at the gradients of magnetic holes on the dayside magnetosheath. The magnetic holes are nonlinear mirror structures which are anticorrelated with particle density. We used expanding box Particle-in-cell simulations and produced the mirror instability magnetic holes. We show that chorus waves are generated at the gradients of magnetic holes in our simulations which is in agreement with MMS observations. We investigate the possible mechanism for enhancing the electron temperature anisotropy at the magnetic field gradients. We analyze the electron pitch angle distributions and electron distribution functions in our simulations and compare it with MMS observations. We also measure the Poynting flux to investigate how much energy is carried away by the fields via chorus waves.

  3. Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus

    NASA Astrophysics Data System (ADS)

    Yang, Chang; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.

    2016-08-01

    Van Allen radiation belt electrons exhibit complex dynamics during geomagnetically active periods. Investigation of electron pitch angle distributions (PADs) can provide important information on the dominant physical mechanisms controlling radiation belt behaviors. Here we report a storm time radiation belt event where energetic electron PADs changed from butterfly distributions to normal or flattop distributions within several hours. Van Allen Probes observations showed that the flattening of butterfly PADs was closely related to the occurrence of whistler-mode chorus waves. Two-dimensional quasi-linear STEERB simulations demonstrate that the observed chorus can resonantly accelerate the near-equatorially trapped electrons and rapidly flatten the corresponding electron butterfly PADs. These results provide a new insight on how chorus waves affect the dynamic evolution of radiation belt electrons.

  4. MMS Super-Conjunction Studies of Chorus Wave Properties and Their Effects on Energetic Electrons

    NASA Astrophysics Data System (ADS)

    Jaynes, A. N.; Baker, D.; Blake, J. B.; Kletzing, C.; Zhao, H.; Leonard, T. W.; Turner, D. L.; Fennell, J. F.; Wilder, F. D.; Kanekal, S. G.; Schiller, Q.; Mauk, B.; Cohen, I.

    2016-12-01

    During the first full sweep of NASA's MMS mission through the Earth's magnetotail, referred to as Phase 1x, the active state of the geomagnetic environment allowed many opportunities for new insights into inner magnetospheric dynamics. Of particular interest is the local generation of whistler-mode chorus waves and their subsequent effect on energetic electrons. In this study, we take advantage of conjunctions between MMS and the rest of the Heliospheric System Observatory satellites, including one super-conjunction event on 01 May 2016, when both Van Allen Probes and MMS were all within 1 Re of each other at the same time. Using multipoint measurements, we examine the properties and effects of chorus in fine detail. This concentration of observation points in the chorus generation region unveils new understanding of the wave-particle interactions that accelerate electrons and form the Earth's radiation belts.

  5. Neurologic amebiasis caused by Balamuthia mandrillaris in an Indian flying fox (Pteropus giganteus).

    PubMed

    Crossland, Nicholas A; Ali, Ibne; Higbie, Christine; Jackson, Jonathan; Pirie, Gordon; Bauer, Rudy

    2016-01-01

    A 4-5-month-old intact male Indian flying fox (Pteropus giganteus) was presented to the Baton Rouge Zoo's veterinary hospital with an acute onset of obtundation that was diagnosed with amebic encephalitis. Histologic examination revealed numerous amebic trophozoites within necrotic foci, affecting the occipital cerebrum and surrounding the mesencephalic aqueduct. The etiologic agent, Balamuthia mandrillaris, was determined by multiplex quantitative real-time polymerase chain reaction, immunohistochemistry, and indirect fluorescent antibody test. The current report documented a case of amebic encephalitis within the order Chiroptera. © 2016 The Author(s).

  6. Avian cholera in a southern giant petrel (Macronectes giganteus) from Antarctica.

    PubMed

    Leotta, G A; Rivas, M; Chinen, I; Vigo, G B; Moredo, F A; Coria, N; Wolcott, M J

    2003-07-01

    A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica.

  7. Roosting behaviour and habitat selection of Pteropus giganteus reveals potential links to Nipah virus epidemiology

    PubMed Central

    Hahn, Micah B.; Epstein, Jonathan H.; Gurley, Emily S.; Islam, Mohammad S.; Luby, Stephen P.; Daszak, Peter; Patz, Jonathan A.

    2014-01-01

    Summary 1. Flying foxes Pteropus spp. play a key role in forest regeneration as seed dispersers and are also the reservoir of many viruses, including Nipah virus in Bangladesh. Little is known about their habitat requirements, particularly in South Asia. Identifying Pteropus habitat preferences could assist in understanding the risk of zoonotic disease transmission broadly, and in Bangladesh, could help explain the spatial distribution of human Nipah virus cases. 2. We analysed characteristics of Pteropus giganteus roosts and constructed an ecological niche model to identify suitable habitat in Bangladesh. We also assessed the distribution of suitable habitat in relation to the location of human Nipah virus cases. 3. Compared to non-roost trees, P. giganteus roost trees are taller with larger diameters, and are more frequently canopy trees. Colony size was larger in densely forested regions and smaller in flood-affected areas. Roosts were located in areas with lower annual precipitation and higher human population density than non-roost sites. 4. We predicted that 2–17% of Bangladesh's land area is suitable roosting habitat. Nipah virus outbreak villages were 2.6 times more likely to be located in areas predicted as highly suitable habitat for P. giganteus compared to non-outbreak villages. 5. Synthesis and applications. Habitat suitability modelling may help identify previously undocumented Nipah outbreak locations and improve our understanding of Nipah virus ecology by highlighting regions where there is suitable bat habitat but no reported human Nipah virus. Conservation and public health education is a key component of P. giganteus management in Bangladesh due to the general misunderstanding and fear of bats that are a reservoir of Nipah virus. Affiliation between Old World fruit bats (Pteropodidae) and people is common throughout their range, and in order to conserve these keystone bat species and prevent emergence of zoonotic viruses, it is imperative that

  8. Roosting behaviour and habitat selection of Pteropus giganteus reveals potential links to Nipah virus epidemiology.

    PubMed

    Hahn, Micah B; Epstein, Jonathan H; Gurley, Emily S; Islam, Mohammad S; Luby, Stephen P; Daszak, Peter; Patz, Jonathan A

    2014-04-01

    1. Flying foxes Pteropus spp. play a key role in forest regeneration as seed dispersers and are also the reservoir of many viruses, including Nipah virus in Bangladesh. Little is known about their habitat requirements, particularly in South Asia. Identifying Pteropus habitat preferences could assist in understanding the risk of zoonotic disease transmission broadly, and in Bangladesh, could help explain the spatial distribution of human Nipah virus cases. 2. We analysed characteristics of Pteropus giganteus roosts and constructed an ecological niche model to identify suitable habitat in Bangladesh. We also assessed the distribution of suitable habitat in relation to the location of human Nipah virus cases. 3. Compared to non-roost trees, P. giganteus roost trees are taller with larger diameters, and are more frequently canopy trees. Colony size was larger in densely forested regions and smaller in flood-affected areas. Roosts were located in areas with lower annual precipitation and higher human population density than non-roost sites. 4. We predicted that 2-17% of Bangladesh's land area is suitable roosting habitat. Nipah virus outbreak villages were 2.6 times more likely to be located in areas predicted as highly suitable habitat for P. giganteus compared to non-outbreak villages. 5. Synthesis and applications. Habitat suitability modelling may help identify previously undocumented Nipah outbreak locations and improve our understanding of Nipah virus ecology by highlighting regions where there is suitable bat habitat but no reported human Nipah virus. Conservation and public health education is a key component of P. giganteus management in Bangladesh due to the general misunderstanding and fear of bats that are a reservoir of Nipah virus. Affiliation between Old World fruit bats (Pteropodidae) and people is common throughout their range, and in order to conserve these keystone bat species and prevent emergence of zoonotic viruses, it is imperative that we

  9. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

    SciTech Connect

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; Yang, Chang; Liu, Si; Baker, D. N.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.

    2015-08-20

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst ≈ –45) and 14 January 2013 (Dst ≈ –18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8 – 6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ~10–4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (~10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations to show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ < 90° or > 90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Furthermore, we examine a dayside event during a small storm C on 8 May 2014 (Dst ≈ –45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.

  10. Van Allen Probes observation and modeling of chorus excitation and propagation during weak geomagnetic activities

    DOE PAGES

    He, Yihua; Xiao, Fuliang; Zhou, Qinghua; ...

    2015-08-20

    We report correlated data on nightside chorus waves and energetic electrons during two small storm periods: 1 November 2012 (Dst ≈ –45) and 14 January 2013 (Dst ≈ –18). The Van Allen Probes simultaneously observed strong chorus waves at locations L = 5.8 – 6.3, with a lower frequency band 0.1–0.5fce and a peak spectral density ~10–4 nT2/Hz. In the same period, the fluxes and anisotropy of energetic (~10–300 keV) electrons were greatly enhanced in the interval of large negative interplanetary magnetic field Bz. Using a bi-Maxwellian distribution to model the observed electron distribution, we perform ray tracing simulations tomore » show that nightside chorus waves are indeed produced by the observed electron distribution with a peak growth for a field-aligned propagation approximately between 0.3fce and 0.4fce, at latitude <7°. Moreover, chorus waves launched with initial normal angles either θ < 90° or > 90° propagate along the field either northward or southward and then bounce back either away from Earth for a lower frequency or toward Earth for higher frequencies. The current results indicate that nightside chorus waves can be excited even during weak geomagnetic activities in cases of continuous injection associated with negative Bz. Furthermore, we examine a dayside event during a small storm C on 8 May 2014 (Dst ≈ –45) and find that the observed anisotropic energetic electron distributions potentially contribute to the generation of dayside chorus waves, but this requires more thorough studies in the future.« less

  11. Observational evidence of generation mechanisms for very oblique lower band chorus using THEMIS waveform data

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Mourenas, Didier; Li, Wen; Artemyev, Anton V.; Lu, Quanming; Tao, Xin; Wang, Shui

    2016-07-01

    Chorus waves are intense coherent whistler mode waves with frequency chirping which play a dual role in both loss and acceleration of radiation belt electrons in the Earth's magnetosphere. Although the generation of parallel chorus waves has been extensively studied by means of theory, simulations, and observations, the generation mechanism of very oblique chorus waves still remains a mystery. In this study, we have analyzed hundreds of very oblique discrete (rising or falling tone) lower band chorus events collected from 7 years of Time History of Events and Macroscale Interactions during Substorms (THEMIS) waveform data to investigate their potential generation mechanisms. Comparisons between wave normal angles directly measured onboard THEMIS in the dawn-day sector at L = 5-9 and inferred from theoretical models on the basis of measured wave characteristics (frequency sweep rate, mean frequency, and amplitude) show that these very oblique waves are more commonly generated through cyclotron resonance with anisotropic electron streams. However, a second generation mechanism via Landau resonance with low-energy electron beams seems to be also operating on the nightside at L < 6.7 and at all local times at L > 8.5. Moreover, very oblique lower band chorus waves with large frequency chirping rates or small magnetic field amplitudes are more likely excited via cyclotron resonance, while waves with small frequency chirping rates or large magnetic field amplitudes are preferentially generated through Landau resonance. This comprehensive statistical study provides interesting insight into the possible generation mechanisms of very oblique lower band chorus waves in the Earth's magnetosphere.

  12. Signal recognition by frogs in the presence of temporally fluctuating chorus-shaped noise

    PubMed Central

    Vélez, Alejandro; Bee, Mark A.

    2010-01-01

    The background noise generated in large social aggregations of calling individuals is a potent source of auditory masking for animals that communicate acoustically. Despite similarities with the so-called “cocktail-party problem” in humans, few studies have explicitly investigated how non-human animals solve the perceptual task of separating biologically relevant acoustic signals from ambient background noise. Under certain conditions, humans experience a release from auditory masking when speech is presented in speech-like masking noise that fluctuates in amplitude. We tested the hypothesis that females of Cope’s gray treefrog (Hyla chrysoscelis) experience masking release in artificial chorus noise that fluctuates in level at modulations rates characteristic of those present in ambient chorus noise. We estimated thresholds for recognizing conspecific advertisement calls (pulse rate=40–50 pulses/s) in the presence of unmodulated and sinusoidally amplitude modulated (SAM) chorus-shaped masking noise. We tested two rates of modulation (5 Hz and 45 Hz) because the sounds of frog choruses are modulated at low rates (e.g., less than 5–10 Hz), and because those of species with pulsatile signals are additionally modulated at higher rates typical of the pulse rate of calls (e.g., between 15–50 Hz). Recognition thresholds were similar in the unmodulated and 5-Hz SAM conditions, and 12 dB higher in the 45-Hz SAM condition. These results did not support the hypothesis that female gray treefrogs experience masking release in temporally fluctuating chorus-shaped noise. We discuss our results in terms of modulation masking, and hypothesize that natural amplitude fluctuations in ambient chorus noise may impair mating call perception. PMID:21170157

  13. Nonlinear sub-cyclotron resonance as a formation mechanism for gaps in banded chorus

    DOE PAGES

    Fu, Xiangrong; Guo, Zehua; Dong, Chuanfei; ...

    2015-05-14

    An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at ω ≃ 0.5Ωe, where Ωe is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near 0.3Ωe and 0.6Ωe. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.

  14. Preliminary Assessment of Tecplot Chorus for Analyzing Ensemble of CTH Simulations

    SciTech Connect

    Agelastos, Anthony Michael; Stevenson, Joel O.; Attaway, Stephen W.; Peterson, David

    2015-04-01

    The exploration of large parameter spaces in search of problem solution and uncertainty quantifcation produces very large ensembles of data. Processing ensemble data will continue to require more resources as simulation complexity and HPC platform throughput increase. More tools are needed to help provide rapid insight into these data sets to decrease manual processing time by the analyst and to increase knowledge the data can provide. One such tool is Tecplot Chorus, whose strengths are visualizing ensemble metadata and linked images. This report contains the analysis and conclusions from evaluating Tecplot Chorus with an example problem that is relevant to Sandia National Laboratories.

  15. GENERAL: A Possible Population-Driven Phase Transition in Cicada Chorus

    NASA Astrophysics Data System (ADS)

    Gu, Si-Yuan; Jin, Yu-Liang; Zhao, Xiao-Xue; Huang, Ji-Ping

    2009-06-01

    We investigate the collective synchronization of cicada chirping. Using both experimental and phenomenological numerical techniques, here we show that the onset of a periodic two-state acoustic synchronous behavior in cicada chorus depends on a critical size of population Nc = 21, above which a typical chorus state appears periodically with a 30 second-silence state in between, and further clarify its possibility concerning a new class of phase transition, which is unusually driven by population. This work has relevance to acoustic synchronization and to general physics of phase transition.

  16. Theoretical Study of the Dynamic Spectra of the Whistler-Chorus Waves in the Ion-Electron Two-Fluid Plasma

    NASA Astrophysics Data System (ADS)

    Huang, Y. C.; Lyu, L. H.

    2016-12-01

    Dynamic spectra of the whistler-chorus waves are studied systematically based on the group-velocity distribution of the waves in the ion-electron two-fluid plasma. Six types of dynamic spectra are obtained in this study. They are (1) quasi-electromagnetic chorus waves with rising-tone dynamic spectra and with a frequency gap near half the electron cyclotron frequency, (2) quasi-electromagnetic chorus waves with rising-tone dynamic spectra but without a frequency gap across half the electron cyclotron frequency, (3) quasi-electrostatic chorus waves followed by quasi-electromagnetic chorus waves with rising-tone dynamic spectra but without a frequency gap across half the electron cyclotron frequency, (4) electromagnetic whistler waves with exponentially falling-tone dynamic spectra, (5) quasi-electrostatic chorus waves with linearly falling-tone dynamic spectra, (6) quasi-electromagnetic chorus waves followed by quasi-electrostatic chorus waves with rising-fall tone hooked dynamic spectra and with frequencies below half the electron cyclotron frequency. Our results also show that the wave normal angles of the quasi-electromagnetic whistler-chorus waves are in general less than the wave normal angles of the quasi-electrostatic chorus waves. The dynamic spectra and the corresponding wave normal angles of the whistler-chorus waves obtained in this study are in good agreement with previous satellite observations. We will also address the possible generation mechanisms of these waves and their impacts on electron accelerations in the inner magnetosphere.

  17. Cool C4 Photosynthesis: Pyruvate Pi Dikinase Expression and Activity Corresponds to the Exceptional Cold Tolerance of Carbon Assimilation in Miscanthus × giganteus12[W][OA

    PubMed Central

    Wang, Dafu; Portis, Archie R.; Moose, Stephen P.; Long, Stephen P.

    2008-01-01

    The bioenergy feedstock grass Miscanthus × giganteus is exceptional among C4 species for its high productivity in cold climates. It can maintain photosynthetically active leaves at temperatures 6°C below the minimum for maize (Zea mays), which allows it a longer growing season in cool climates. Understanding the basis for this difference between these two closely related plants may be critical in adapting maize to colder weather. When M. × giganteus and maize grown at 25°C were transferred to 14°C, light-saturated CO2 assimilation and quantum yield of photosystem II declined by 30% and 40%, respectively, in the first 48 h in these two species. The decline continued in maize but arrested and then recovered partially in M. × giganteus. Within 24 h of the temperature transition, the pyruvate phosphate dikinase (PPDK) protein content per leaf area transiently declined in M. × giganteus but then steadily increased, such that after 7 d the enzyme content was significantly higher than in leaves growing in 25°C. By contrast it declined throughout the chilling period in maize leaves. Rubisco levels remained constant in M. × giganteus but declined in maize. Consistent with increased PPDK protein content, the extractable PPDK activity per unit leaf area (Vmax,ppdk) in cold-grown M. × giganteus leaves was higher than in warm-grown leaves, while Vmax,ppdk was lower in cold-grown than in warm-grown maize. The rate of light activation of PPDK was also slower in cold-grown maize than M. × giganteus. The energy of activation (Ea) of extracted PPDK was lower in cold-grown than warm-grown M. × giganteus but not in maize. The specific activities and Ea of purified recombinant PPDK from M. × giganteus and maize cloned into Escherichia coli were similar. The increase in PPDK protein in the M. × giganteus leaves corresponded to an increase in PPDK mRNA level. These results indicate that of the two enzymes known to limit C4 photosynthesis, increase of PPDK, not Rubisco

  18. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

    SciTech Connect

    Hartley, D. P.; Chen, Y.; Kletzing, C. A.; Denton, M. H.; Kurth, W. S.

    2015-01-26

    Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1–0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10⁻³ nT², using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.

  19. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

    DOE PAGES

    Hartley, D. P.; Chen, Y.; Kletzing, C. A.; ...

    2015-01-26

    Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1–0.9 fce). Results from this study indicate that the calculated wavemore » intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10⁻³ nT², using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.« less

  20. Intense low-frequency chorus waves observed by Van Allen Probes: Fine structures and potential effect on radiation belt electrons

    NASA Astrophysics Data System (ADS)

    Gao, Zhonglei; Su, Zhenpeng; Zhu, Hui; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Shen, Chao; Wang, Shui

    2016-02-01

    Frequency distribution is a vital factor in determining the contribution of whistler mode chorus to radiation belt electron dynamics. Chorus is usually considered to occur in the frequency range 0.1-0.8fce_eq (with the equatorial electron gyrofrequency fce_eq). We here report an event of intense low-frequency chorus with nearly half of wave power distributed below 0.1fce_eq observed by Van Allen Probe A on 27 August 2014. This emission propagated quasi-parallel to the magnetic field and exhibited hiss-like signatures most of the time. The low-frequency chorus can produce the rapid loss of low-energy (˜0.1 MeV) electrons, different from the normal chorus. For high-energy (≥0.5 MeV) electrons, the low-frequency chorus can yield comparable momentum diffusion to that of the normal chorus but much stronger (up to 2 orders of magnitude) pitch angle diffusion near the loss cone.

  1. Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes.

    PubMed

    Hartley, D P; Chen, Y; Kletzing, C A; Denton, M H; Kurth, W S

    2015-02-01

    Most theoretical wave models require the power in the wave magnetic field in order to determine the effect of chorus waves on radiation belt electrons. However, researchers typically use the cold plasma dispersion relation to approximate the magnetic wave power when only electric field data are available. In this study, the validity of using the cold plasma dispersion relation in this context is tested using Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) observations of both the electric and magnetic spectral intensities in the chorus wave band (0.1-0.9 fce). Results from this study indicate that the calculated wave intensity is least accurate during periods of enhanced wave activity. For observed wave intensities >10(-3) nT(2), using the cold plasma dispersion relation results in an underestimate of the wave intensity by a factor of 2 or greater 56% of the time over the full chorus wave band, 60% of the time for lower band chorus, and 59% of the time for upper band chorus. Hence, during active periods, empirical chorus wave models that are reliant on the cold plasma dispersion relation will underestimate chorus wave intensities to a significant degree, thus causing questionable calculation of wave-particle resonance effects on MeV electrons.

  2. Restrictions on the Quasi-Linear Description of Electron-Chorus Interaction in the Earth's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Sibeck, David G.

    2013-01-01

    The interaction of electrons with coherent chorus waves in the random phase approximation can be described as quasi-linear diffusion for waves with amplitudes below some limit. The limit is calculated for relativistic and non-relativistic electrons. For stronger waves, the friction force should be taken into account.

  3. Student Voice Use and Vocal Health during an All-State Chorus Event

    ERIC Educational Resources Information Center

    Daugherty, James F.; Manternach, Jeremy N.; Price, Kathy K.

    2011-01-01

    This field-based case study documented students' (N = 256) voice use and voice health perceptions during a 3-day all-state high school chorus event through daily surveys, phonation duration data, analysis of rehearsal voice use behaviors, and field notes. Among the primary results are the following: (a) First and final day survey comparisons…

  4. Simulation of VLF chorus emissions in the magnetosphere and comparison with THEMIS spacecraft data

    NASA Astrophysics Data System (ADS)

    Demekhov, A. G.; Taubenschuss, U.; Santolík, O.

    2017-01-01

    We present results of numerical simulations of VLF chorus emissions based on the backward wave oscillator model and compare them with Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft data from the equatorial chorus source region on the early morning side at a radial distance of 6 Earth radii. Specific attention is paid to the choice of simulation parameters based on experimental data. We show that with known parameters of the geomagnetic field, plasma density, and the initial wave frequency, one can successfully reproduce individual chorus elements in the simulation. In particular, the measured growth rate, wave amplitude, and frequency drift rate are in agreement with observed values. The characteristic interval between the elements has a mismatch of factor 2. The agreement becomes perfect if we assume that the inhomogeneity scale of the magnetic field along the field line is half of that obtained from the T96 model. Such an assumption can be justified since the T96 model does not fit well for the time of chorus observations, and there is a shear in the observed field which indicates the presence of local currents.

  5. CIMI simulations with recently developed multi-parameter chorus and plasmaspheric hiss models

    NASA Astrophysics Data System (ADS)

    Aryan, Homayon; Sibeck, David; Kang, Suk-bin; Balikhin, Michael; Fok, Mei-ching

    2017-04-01

    Simulation studies of the Earth's radiation belts are very useful in understanding the acceleration and loss of energetic particles. The Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model considers the effects of the ring current and plasmasphere on the radiation belts. CIMI was formed by merging the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model to solves for many essential quantities in the inner magnetosphere, including radiation belt enhancements and dropouts. It incorporates chorus and plasmaspheric hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. Usually the chorus and plasmaspheric hiss models used in CIMI are based on single-parameter geomagnetic index (AE). Here we integrate recently developed multi-parameter chorus and plasmaspheric hiss wave models based on geomagnetic index and solar wind parameters. We then perform CIMI simulations for different storms and compare the results with data from the Van Allen Probes and the Two Wide-angle Imaging Neutral-atom Spectrometers and Akebono satellites. We find that the CIMI simulations with multi-parameter chorus and plasmaspheric hiss wave models are more comparable to data than the single-parameter wave models.

  6. New chorus wave properties near the equator from Van Allen Probes wave observations

    NASA Astrophysics Data System (ADS)

    Li, W.; Santolik, O.; Bortnik, J.; Thorne, R. M.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.

    2016-05-01

    The chorus wave properties are evaluated using Van Allen Probes data in the Earth's equatorial magnetosphere. Two distinct modes of lower band chorus are identified: a quasi-parallel mode and a quasi-electrostatic mode, whose wave normal direction is close to the resonance cone. Statistical results indicate that the quasi-electrostatic (quasi-parallel) mode preferentially occurs during relatively quiet (disturbed) geomagnetic activity at lower (higher) L shells. Although the magnetic intensity of the quasi-electrostatic mode is considerably weaker than the quasi-parallel mode, their electric intensities are comparable. A newly identified feature of the quasi-electrostatic mode is that its frequency peaks at higher values compared to the quasi-parallel mode that exhibits a broad frequency spectrum. Moreover, upper band chorus wave normal directions vary between 0° and the resonance cone and become more parallel as geomagnetic activity increases. Our new findings suggest that chorus-driven energetic electron dynamics needs a careful examination by considering the properties of these two distinct modes.

  7. A cyclotron resonance model of VLF chorus emissions detected during electron microburst precipitation

    NASA Astrophysics Data System (ADS)

    Skoug, R. M.; Datta, S.; McCarthy, M. P.; Parks, G. K.

    1996-10-01

    VLF chorus, consisting of narrowband rising frequency emissions, has often been observed in association with microburst electron precipitation. We present the first simultaneous rocket observations of these two phenomena, with emphasis on understanding the source of the VLF emissions. The rocket experiment was launched on May 6, 1993, from Poker Flat, Alaska (L=5.6). In this work, the observed 1-4 kHz chorus emissions are interpreted in terms of a cyclotron resonance interaction. The frequency range of the risers and the observed electron energy range agree with those required for this interaction. Using a criterion derived from the conservation of energy during an interaction, it is shown that a cold plasma cyclotron resonance interaction can produce the lower-frequency portions of the observed chorus risers, from ~1000 Hz to ~2500 Hz, while a warm plasma model is required to produce frequencies >2500 Hz. The warm plasma model assumes a two-component plasma, with an isotropic cold component and a bi-Maxwellian warm component. The effect of the warm component is to change the wave dispersion relation, allowing the production of the higher-frequency risers. A portion of the anisotropy required to produce the high-frequency emissions can also be provided by a loss cone distribution. The chorus source is estimated from this cyclotron resonance theory to be located near the equatorial plane.

  8. Generation of extremely low frequency chorus in Van Allen radiation belts

    NASA Astrophysics Data System (ADS)

    Xiao, Fuliang; Liu, Si; Tao, Xin; Su, Zhenpeng; Zhou, Qinghua; Yang, Chang; He, Zhaoguo; He, Yihua; Gao, Zhonglei; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.

    2017-03-01

    Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasma sheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes, but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency, relativistic effects should be considered in the formula for whistler mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm and firstly demonstrate, using a fully relativistic simulation, that electrons with the high-energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 fce. The simulated wave growth displays a very similar pattern to the observations. The current results can be applied to Jupiter, Saturn, and other magnetized planets.

  9. Student Voice Use and Vocal Health during an All-State Chorus Event

    ERIC Educational Resources Information Center

    Daugherty, James F.; Manternach, Jeremy N.; Price, Kathy K.

    2011-01-01

    This field-based case study documented students' (N = 256) voice use and voice health perceptions during a 3-day all-state high school chorus event through daily surveys, phonation duration data, analysis of rehearsal voice use behaviors, and field notes. Among the primary results are the following: (a) First and final day survey comparisons…

  10. A function of synchronous chorusing and a novel female preference shift in an anuran

    PubMed Central

    Grafe, T. U.

    1999-01-01

    Many chorusing insects and anurans acoustically compete for females under conditions of high background noise produced by conspecifics and have developed a variety of strategies for improving their conspicuousness in a chorus. In this study, I present a novel female preference shift that can explain the synchronous chorusing of males. In the running frog Kassina fusca the median degree of overlap found in pairwise interactions between males (20.8%) and in response to playbacks of conspecific calls (21.4%) corresponded remarkably well with the preference function of females. Although preferring follower male calls when the degree of call overlap was low (10 and 25%), females shifted their preference towards leader male calls when the degree of call overlap was high (75 and 90%). Males were physiologically capable of calling with short latencies and, thus, high degrees of overlap. This suggests that follower males can control the degree of overlap with neighbours and do so to their advantage. These results stand in contrast to recent findings in insects and anurans in which chorusing structure has been described as an epiphenomenon.

  11. Formation Process of Relativistic Electron Flux Through Interaction with Chorus Emissions in the Earth's Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Omura, Y.; Miyashita, Y.; Yoshikawa, M.; Summers, D.; Hikishima, M.; Ebihara, Y.; Kubota, Y.

    2015-12-01

    We perform test particle simulations of energetic electrons interacting with whistler-mode chorus emissions. We compute trajectories of a large number of electrons forming a delta function with the same energy and pitch angle. The electrons are launched at different locations along the magnetic field line and different timings with respect to a pair of chorus emissions generated at the magnetic equator. We follow the evolution of the delta function, and obtain a distribution function in energy and equatorial pitch angle, which is a numerical Green's function for one cycle of chorus wave-particle interaction. We obtain the Green's functions for the energy range 10 keV ˜ 6 MeV and all pitch angles greater than the loss cone angle. By taking the convolution integral of the Green's functions with the distribution function of the injected electrons repeatedly, we follow a long-time evolution of the distribution function. We find that the energetic electrons are accelerated effectively by relativistic turning acceleration and ultra-relativistic acceleration through nonlinear trapping by chorus emissions, and that these processes result in the rapid formation of a dumbbell distribution of highly relativistic electrons within a few minutes after the injection of tens of keV electrons.

  12. Revealing the generation of extremely low frequency chorus in Van Allen radiation belts

    DOE PAGES

    Xiao, Fuliang; Liu, Si; Tao, Xin; ...

    2017-03-02

    Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasmasheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency relativistic effects should be considered in the formula for whistler-mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm andmore » firstly demonstrate, using a fully relativistic simulation, that electrons with the high energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 fce. The simulated wave growth displays a very similar pattern to the observations. Finally, the current results can be applied to Jupiter, Saturn and other magnetized planets.« less

  13. Measurements of the self-to-other ratio in an opera chorus in performance

    NASA Astrophysics Data System (ADS)

    Ternstrom, Sten; Davis, Pamela

    2004-05-01

    The objective of this study was to obtain measurements of the self-to-other ratio (SOR) in the opera chorus on stage. Four members of the opera chorus of Opera Australia volunteered to carry wireless binaural microphones during a dress rehearsal of Verdi's The Masked Ball, in the Sydney Opera House. Conditions were those of actual performance in costume, with soloists and orchestra. Hence, the recordings are very realistic, if acoustically not so stringently controlled. The SOR was estimated from the recordings using M/S matrixing, complemented with L-R correlation by adaptive filtering. The results indicate how much louder the singers heard themselves relative to the rest of the ensemble, including the orchestra. The SOR varied with score and on-stage formation, but was 4-8 dB higher than in ordinary choirs (not opera), as might be expected from the podium acoustics. While each opera chorus artist can hear his or her own voice very well, they often hear less of the rest of the chorus and very little of the orchestra. This was borne out in informal listening; the orchestra often became inaudible once the choir entered its louder passages. [Work supported by the Australian Research Council under the SPIRT program.

  14. Nonlinearity in Chorus Waves During a Geomagnetic Storm on 1 November 2012

    NASA Astrophysics Data System (ADS)

    Matsui, H.; Paulson, K. W.; Torbert, R. B.; Spence, H.; Kletzing, C.; Kurth, W. S.; Skoug, R. M.; Larsen, B.

    2013-12-01

    In this study, we investigate possibility of nonlinearity in chorus waves during a geomagnetic storm on 1 November 2012. The data we use are measured by the Van Allen Probes B (RBSP-B). Wave data from the EMFISIS instrument and particle data from the ECT instrument are analyzed. HOPE instrument on ECT provides measurements of plasmasheet electrons. Chorus waves are frequently measured in the morning side during the main phase of this storm. During this storm interval, large amplitude chorus waves are seen with amplitudes of the order of ~0.6 nT and >7 mV/m, which is similar to or larger than the size of ULF waves. The waves quite often consist of rising tones during the burst sampling. Since the rising tone is known as a signature of nonlinearity, the large portion of the waves are considered as nonlinear at least during the burst sampling. These results underline the importance of nonlinearity in the dynamics of chorus waves. We further examine the consistency between the measurement and the nonlinear theory. For example, the relation between wave amplitudes and frequency drift rate is checked.

  15. Quantitative Assessment of MeV Electron Acceleration in Non-Linear Interactions with VLF Chorus

    NASA Astrophysics Data System (ADS)

    Foster, J. C.; Erickson, P. J.; Omura, Y.; Baker, D. N.

    2016-12-01

    For occurrences of apparent rapid acceleration of radiation belt electrons to MeV energies at L 4, we examine the energy gained by seed electrons in non-linear (NL) interactions with VLF chorus rising tones. For the 17-18 March 2013 storm, observations of outer zone radiation belt electron populations were made with the magEIS and REPT instruments on Van Allen Probes A & B. These reveal that MeV electron fluxes at L=4.2 increased 10-fold in 30 min at the times of 30 - 100 keV electron injections during "substorm" dipolarizations. Simultaneous enhancements of VLF chorus were observed with the EMFISIS wave instruments. Three-axis burst mode observations of wave electric and magnetic fields have been used to investigate electron interactions with individual chorus rising tones on a sub millisecond time scale. Wave amplitudes at 2500 Hz were 1 nT (|B|) and 30 mV/m (|E|). Frequency - time characteristics of the observed chorus elements closely match those predicted by NL electron-chorus interaction modeling [Omura et al., 2015, J. Geophys. Res. Space Phys., 120, doi:10.1002/2015JA021563]. For seed electrons with initial energies 50 keV to 8 MeV, subpacket wave analysis was used to quantify resonant electron energy gain both by relativistic turning acceleration and by ultrarelativistic acceleration through nonlinear trapping by the chorus waves. Electrons with 1-2 MeV initial energy can experience a 300 keV total energy gain in NL interactions with a single 200 msec rising tone. Maximum energy gain from interaction with a single 10 msec subpacket was 100 keV for a 2 MeV seed electron. Examining a number of chorus elements at different locations during the rapid local acceleration of the radiation belt during this event, we conclude that seed electrons (100s keV - 5 MeV) can be accelerated by 50 keV - 500 keV in resonant NL interactions with a single VLF rising tone on a time scale of 10-100 msec.

  16. Chorus Whistler Wave Source Scales As Determined From Multipoint Van Allen Probe Measurements

    NASA Technical Reports Server (NTRS)

    Agapitov, O.; Blum, L. W.; Mozer, F. S.; Bonnell, J. W.; Wygant, J.

    2017-01-01

    Whistler mode chorus waves are particularly important in outer radiation belt dynamics due to their key role in controlling the acceleration and scattering of electrons over a very wide energy range. The key parameters for both nonlinear and quasi-linear treatment of wave-particle interactions are the temporal and spatial scales of the wave source region and coherence of the wave field perturbations. Neither the source scale nor the coherence scale is well established experimentally, mostly because of a lack of multipoint VLF waveform measurements. We present an unprecedentedly long interval of coordinated VLF waveform measurements (sampled at 16384 s(exp -1)) aboard the two Van Allen Probes spacecraft-9 h (0800-1200 UT and 1700-2200 UT) during two consecutive apogees on 15 July 2014. The spacecraft separations varied from about 100 to 5000 km (mostly radially); measurements covered an L shell range from 3 to 6; magnetic local time 0430-0900, and magnetic latitudes were approximately 15 and approximately 5 deg during the two orbits. Using time-domain correlation techniques, the single chorus source spatial extent transverse to the background magnetic field has been determined to be about 550-650 km for upper band chorus waves with amplitudes less than 100 pT and up to 800 km for larger amplitude, lower band chorus waves. The ratio between wave amplitudes measured on the two spacecraft is also examined to reveal that the wave amplitude distribution within a single chorus element generation area can be well approximated by a Gaussian exp(-0.5 x r (exp 2)/r(sub 0)(exp 2)), with the characteristic scale r(sub 0) around 300 km. Waves detected by the two spacecraft were found to be coherent in phase at distances up to 400 km.

  17. High Resolution Spectral Analysis of Hiss and Chorus Emissions in Ground Based Data

    NASA Astrophysics Data System (ADS)

    Hosseini Aliabad, S. P.; Golkowski, M.; Gibby, A. R.

    2015-12-01

    The dynamic evolution of the radiation belts is believed to be controlled in large part by two separate but related classes of naturally occurring plasma waves: ELF/VLF chorus and hiss emissions. Although whistler mode chorus has been extensively studied since the first reports by Storey in 1953, the source mechanism and properties are still subjects of active research. Moreover, the origin of plasmaspheric hiss, the electromagnetic emission believed to be responsible for the gap between the inner and outer radiation belts, has been debated for over four decades. Although these waves can be observed in situ on spacecraft, ground-based observing stations can provide orders of magnitude higher data volumes and decades long data coverage essential for certain long-term and statistical studies of wave properties. Recent observational and theoretical works suggest that high resolution analysis of the spectral features of both hiss and chorus emissions can provide insight into generation processes and be used to validate existing theories. Application of the classic Fourier (FFT) technique unfortunately yields a tradeoff between time and frequency resolution. In additional to Fourier spectra, we employ novel methods to make spectrograms with high time and frequency resolutions, independently using minimum variance distortionless response (MVDR). These techniques are applied to ground based data observations of hiss and chorus made in Alaska. Plasmaspheric hiss has been widely regarded as a broadband, structure less, incoherent emission. We quantify the extent to which plasmaspheric hiss can be a coherent emission with complex fine structure. Likewise, to date, researchers have differentiated between hiss and chorus coherency primarily using qualitative "naked eye" approaches to amplitude spectra. Using a quantitative approach to observed amplitude and we present more rigorous classification criteria for these emissions.

  18. Sub-zero cold tolerance of Spartina pectinata (prairie cordgrass) and Miscanthus × giganteus: candidate bioenergy crops for cool temperate climates

    PubMed Central

    Peixoto, Murilo de Melo; Lee, D. K.; Sage, Rowan F.

    2015-01-01

    Miscanthus × giganteus grown in cool temperate regions of North America and Europe can exhibit severe mortality in the year after planting, and poor frost tolerance of leaves. Spartina pectinata (prairie cordgrass), a productive C4 perennial grass native to North America, has been suggested as an alternative biofuel feedstock for colder regions; however, its cold tolerance relative to M. × giganteus is uncertain. Here, we compare the cold tolerance thresholds for winter-dormant rhizomes and spring/summer leaves of M. × giganteus and three accessions of S. pectinata. All genotypes were planted at a field site in Ontario, Canada. In November and February, the temperatures corresponding to 50% rhizome mortality (LT50) were near −24°C for S. pectinata and −4°C for M. × giganteus. In late April, the LT50 of rhizomes rose to −10°C for S. pectinata but remained near −4°C for M. × giganteus. Twenty percent of the M. × giganteus rhizomes collected in late April were dead while S. pectinata rhizomes showed no signs of winter injury. Photosynthesis and electrolyte leakage measurements in spring and summer demonstrate that S. pectinata leaves have greater frost tolerance in the field. For example, S. pectinata leaves remained viable above −9°C while the mortality threshold was near −5°C for M. × giganteus. These results indicate M. × giganteus will be unsuitable for production in continental interiors of cool-temperate climate zones unless freezing and frost tolerance are improved. By contrast, S. pectinata has the freezing and frost tolerance required for a higher-latitude bioenergy crop. PMID:25873680

  19. New Holocene refugia of giant deer (Megaloceros giganteus Blum.) in Siberia: updated extinction patterns

    NASA Astrophysics Data System (ADS)

    van der Plicht, J.; Molodin, V. I.; Kuzmin, Y. V.; Vasiliev, S. K.; Postnov, A. V.; Slavinsky, V. S.

    2015-04-01

    We obtained new data on the existence of giant deer (Megaloceros giganteus Blum.) in Siberia during the Holocene. Bones and antler of giant deer from new localities in western (Baraba forest steppe) and eastern (Angara River basin) Siberia are dated by radiocarbon, ranging 7900-10,300 BP (ca 8800-12,200 cal BP). Based on these data, we can extend the 'Siberian' Early Holocene habitat of giant deer at least 2400 km to the east compared to previous works. The final extinction of giant deer turned out to be more complex than it was previously thought, with perhaps relatively large refugium in Western Siberia at 7900-7000 BP (ca 8800-7900 cal BP) which was reduced to the Trans-Urals region at 7000-6800 BP (ca 7900-7600 cal BP).

  20. Comparing the performance of Miscanthus x giganteus and wheat straw biomass in sulfuric acid based pretreatment.

    PubMed

    Kärcher, M A; Iqbal, Y; Lewandowski, I; Senn, T

    2015-03-01

    The objective of this study was to assess and compare the suitability of Miscanthus x giganteus and wheat straw biomass in dilute acid catalyzed pretreatment. Miscanthus and wheat straw were treated in a dilute sulfuric acid/steam explosion pretreatment. As a result of combining dilute sulfuric acid- and steam explosion pretreatment the hemicellulose hydrolysis yields (96% in wheat straw and 90% in miscanthus) in both substrates were higher than reported in literature. The combined severity factor (=CSF) for optimal hemicellulose hydrolysis was 1.9 and 1.5 in for miscanthus and wheat straw respectively. Because of the higher CSF value more furfural, furfuryl alcohol, 5-hydroxymethylfurfural and acetic acid was formed in miscanthus than in wheat straw pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Increased metal concentrations in giant sungazer lizards (Smaug giganteus) from mining areas in South Africa.

    PubMed

    McIntyre, Trevor; Whiting, Martin J

    2012-11-01

    Environmental contaminants from anthropogenic activity such as mining can have profound health effects on the animals living in adjacent areas. We investigated whether inorganic contaminants associated with gold-mining waste discharges were accumulated by a threatened species of lizard, Smaug giganteus, in South Africa. Lizards were sampled from two mining sites and two control sites. Blood samples from the most contaminated mining site had significantly greater concentrations of lithium, sodium, aluminum, sulfur, silicon, chromium, manganese, iron, nickel, copper, tungsten, and bismuth than the remaining sites. Contaminant concentrations were not significantly related to lizard body condition, although these relationships were consistently negative. The adult sex ratio of the population inhabiting the most contaminated site also deviated from an expected 1:1 ratio in favour of female lizards. We demonstrate that lizards at these mining sites contained high concentrations of heavy metals that may be imposing as yet poorly understood costs to these lizards.

  2. Gammaherpesvirus infection in a free-ranging eastern grey kangaroo (Macropus giganteus).

    PubMed

    Wilcox, R S; Vaz, P; Ficorilli, N P; Whiteley, P L; Wilks, C R; Devlin, J M

    2011-01-01

    A gammaherpesvirus was detected by polymerase chain reaction (PCR) in ocular, nasal and oropharyngeal swab samples collected from an adult free-ranging male eastern grey kangaroo (Macropus giganteus) with clinical signs of severe respiratory disease. This is the first time a gammaherpesvirus has been detected in a free-ranging macropod in Australia. The nucleotide sequence of a conserved region of the DNA polymerase gene of the detected virus showed a high degree of identity to a gammaherpesvirus recently detected in a zoological collection of eastern grey kangaroos in North America. The detection of this gammaherpesvirus in a free-ranging, native eastern grey kangaroo provides evidence that this species is a natural host. © 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.

  3. Purification and characterization of the exopolygalacturonase produced by Aspergillus giganteus in submerged cultures.

    PubMed

    Pedrolli, Danielle Biscaro; Carmona, Eleonora Cano

    2010-06-01

    Polygalacturonases are pectinolytic enzymes that catalyze the hydrolysis of the plant cell-wall pectin backbone. They are widely used in the food industry for juice extraction and clarification. Aspergillus giganteus produces one polygalacturonase (PG) on liquid Vogel medium with citrus pectin as the only carbon source. In specific applications, such as those used in the food and medicine industries, the PG must be free of substances that could affect the characteristics of the product and the process, such as color, flavor, toxicity, and inhibitors. We present here an efficient, simple, and inexpensive method for purifying the A. giganteus PG and describe the characteristics of the purified enzyme. Purified PG was obtained after two simple steps: (1) protein precipitation with 70% ammonium sulfate saturation and (2) anion-exchange chromatography on a DEAE-Sephadex A-50 column. The final enzyme solution retained 86.4% of its initial PG activity. The purified PG had a molecular weight of 69.7 kDa, exhibited maximal activity at pH 6.0 and 55-60 degrees C, and was stable in neutral and alkaline media. It had a half-life of 115, 18, and 6 min at 40, 50 and 55 degrees C, respectively. Purified PG showed its highest hydrolytic activity with low-esterified and nonesterified substrates, releasing monogalacturonic acid from substrate, indicating that it is an exopolygalacturonase. PG activity was enhanced in the presence of beta-mercaptoethanol, dithiothreitol, Co(2+), Mn(2+), Mg(2+), NH(4) (+), and Na(+) and was resistant to inhibition by Pb(2+).

  4. Pleurotus giganteus (Berk.) Karunarathna & K.D. Hyde: Nutritional value and in vitro neurite outgrowth activity in rat pheochromocytoma cells

    PubMed Central

    2012-01-01

    Background Drugs dedicated to alleviate neurodegenerative diseases like Parkinson’s and Alzheimer’s have always been associated with debilitating side effects. Medicinal mushrooms which harness neuropharmacological compounds offer a potential possibility for protection against such diseases. Pleurotus giganteus (formerly known as Panus giganteus) has been consumed by the indigenous people in Peninsular Malaysia for many years. Domestication of this wild mushroom is gaining popularity but to our knowledge, medicinal properties reported for this culinary mushroom are minimal. Methods The fruiting bodies P. giganteus were analysed for its nutritional values. Cytotoxicity of the mushroom’s aqueous and ethanolic extracts towards PC12, a rat pheochromocytoma cell line was assessed by using 3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Neurite outgrowth stimulation assay was carried out with nerve growth factor (NGF) as control. To elucidate signaling mechanisms involved by mushroom extract-induced neurite outgrowth, treatment of specific inhibitor for MEK/ERK and PI3K signalling pathway was carried out. Results The fruiting bodies of P. giganteus were found to have high carbohydrate, dietary fibre, potassium, phenolic compounds and triterpenoids. Both aqueous and ethanolic extracts induced neurite outgrowth of PC12 cells in a dose- and time-dependant manner with no detectable cytotoxic effect. At day 3, 25 μg/ml of aqueous extract and 15 μg/ml of ethanolic extract showed the highest percentage of neurite-bearing cells, i.e. 31.7 ± 1.1% and 33.3 ± 0.9%; respectively. Inhibition treatment results suggested that MEK/ERK and PI3K/Akt are responsible for neurite outgrowth of PC12 cells stimulated by P. giganteus extract. The high potassium content (1345.7 mg/100 g) may be responsible for promoting neurite extension, too. Conclusions P. giganteus contains bioactive compounds that mimic NGF and are responsible for neurite

  5. Pleurotus giganteus (Berk.) Karunarathna & K.D. Hyde: Nutritional value and in vitro neurite outgrowth activity in rat pheochromocytoma cells.

    PubMed

    Phan, Chia-Wei; Wong, Wei-Lun; David, Pamela; Naidu, Murali; Sabaratnam, Vikineswary

    2012-07-19

    Drugs dedicated to alleviate neurodegenerative diseases like Parkinson's and Alzheimer's have always been associated with debilitating side effects. Medicinal mushrooms which harness neuropharmacological compounds offer a potential possibility for protection against such diseases. Pleurotus giganteus (formerly known as Panus giganteus) has been consumed by the indigenous people in Peninsular Malaysia for many years. Domestication of this wild mushroom is gaining popularity but to our knowledge, medicinal properties reported for this culinary mushroom are minimal. The fruiting bodies P. giganteus were analysed for its nutritional values. Cytotoxicity of the mushroom's aqueous and ethanolic extracts towards PC12, a rat pheochromocytoma cell line was assessed by using 3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Neurite outgrowth stimulation assay was carried out with nerve growth factor (NGF) as control. To elucidate signaling mechanisms involved by mushroom extract-induced neurite outgrowth, treatment of specific inhibitor for MEK/ERK and PI3K signalling pathway was carried out. The fruiting bodies of P. giganteus were found to have high carbohydrate, dietary fibre, potassium, phenolic compounds and triterpenoids. Both aqueous and ethanolic extracts induced neurite outgrowth of PC12 cells in a dose- and time-dependant manner with no detectable cytotoxic effect. At day 3, 25 μg/ml of aqueous extract and 15 μg/ml of ethanolic extract showed the highest percentage of neurite-bearing cells, i.e. 31.7 ± 1.1% and 33.3 ± 0.9%; respectively. Inhibition treatment results suggested that MEK/ERK and PI3K/Akt are responsible for neurite outgrowth of PC12 cells stimulated by P. giganteus extract. The high potassium content (1345.7 mg/100 g) may be responsible for promoting neurite extension, too. P. giganteus contains bioactive compounds that mimic NGF and are responsible for neurite stimulation. Hence, this mushroom may be

  6. Failure of androgenesis in Miscanthus × giganteus in vitro culture of cytologically unbalanced microspores.

    PubMed

    Żur, Iwona; Dubas, Ewa; Słomka, Aneta; Dubert, Franciszek; Kuta, Elżbieta; Płażek, Agnieszka

    2013-09-01

    Miscanthus × giganteus is a popular energy crop, which due to its hybrid origin is only vegetatively reproduced. Asexual embryogenesis in anther and microspore culture leading to double haploids production could allow to regain the ability for sexual reproduction and to increase the biodiversity of the species. Therefore, the goal of this paper was to investigate the requirements of androgenesis in Miscanthus. The standard protocols used for monocotyledonous plants were applied with many modifications regarding the developmental stage of the explants at the time of culture initiation, stress treatment applied to panicles and isolated anthers as well as various chemical and physical parameters of in vitro culture conditions. Our results indicated that the induction of androgenesis in M. × giganteus is possible. However, the very low efficiency of the process and the lack of regeneration ability of the androgenic structures presently prevent the use of this technique.

  7. Nonlinear sub-cyclotron resonance as a formation mechanism for gaps in banded chorus

    SciTech Connect

    Fu, Xiangrong; Guo, Zehua; Dong, Chuanfei; Gary, S. Peter

    2015-05-14

    An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at ω ≃ 0.5Ωe, where Ωe is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near 0.3Ωe and 0.6Ωe. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.

  8. Spatio-Temporal Dynamics in Collective Frog Choruses Examined by Mathematical Modeling and Field Observations

    NASA Astrophysics Data System (ADS)

    Aihara, Ikkyu; Mizumoto, Takeshi; Otsuka, Takuma; Awano, Hiromitsu; Nagira, Kohei; Okuno, Hiroshi G.; Aihara, Kazuyuki

    2014-01-01

    This paper reports theoretical and experimental studies on spatio-temporal dynamics in the choruses of male Japanese tree frogs. First, we theoretically model their calling times and positions as a system of coupled mobile oscillators. Numerical simulation of the model as well as calculation of the order parameters show that the spatio-temporal dynamics exhibits bistability between two-cluster antisynchronization and wavy antisynchronization, by assuming that the frogs are attracted to the edge of a simple circular breeding site. Second, we change the shape of the breeding site from the circle to rectangles including a straight line, and evaluate the stability of two-cluster and wavy antisynchronization. Numerical simulation shows that two-cluster antisynchronization is more frequently observed than wavy antisynchronization. Finally, we recorded frog choruses at an actual paddy field using our sound-imaging method. Analysis of the video demonstrated a consistent result with the aforementioned simulation: namely, two-cluster antisynchronization was more frequently realized.

  9. Chorus wave amplification: A free electron laser in the Earth's magnetosphere

    SciTech Connect

    Soto-Chavez, A. R.; Bhattacharjee, A.; Ng, C. S.

    2012-01-15

    A new theoretical model for whistler-mode chorus amplification in the Earth's magnetosphere is presented. We derive, based on the free-electron laser mechanism in a high-gain amplifier, a new closed set of self-consistent relativistic equations that couple the Hamiltonian equations for particles with Maxwell's equations. We demonstrate that these equations predict, through a cubic equation, whistler amplification levels in good agreement with those observed in the Earth's magnetosphere.

  10. Critical electron pitch angle anisotropy necessary for chorus generation. [Doppler-shifted cyclotron resonance

    NASA Technical Reports Server (NTRS)

    Burton, R. K.

    1976-01-01

    Simultaneous wave, resonant-particle, and ambient-plasma data from OGO 5 for chorus emissions on August 15, 1968, were found consistent with the theoretical critical pitch-angle-anisotropy condition for whistler-mode instability by Doppler-shifted electron cyclotron resonance. Local generation, as determined by wave normal measurements, occurred only when the pitch-angle anisotropy of resonant electrons required for instability substantially exceeded the critical anisotropy defined by Kennel and Petschek (1966).

  11. Polarization analysis of VLF/ELF chorus waves observed at two ground stations at subauroral latitudes

    NASA Astrophysics Data System (ADS)

    Martinez C., C.; Shiokawa, K.; Miyoshi, Y.; Ozaki, M.; Schofield, I.; Connors, M. G.

    2013-12-01

    Chorus waves are naturally occurring and very intense electromagnetic whistler-mode wave emissions, generated near the geomagnetic equator and propagating through the geomagnetic field lines to the ionosphere. They are believed to be of a major contribution to the acceleration and loss of radiation belt particles (Omura et al., 2007, Inan et al., 1982). The spatial and temporal variations of the acceleration region of radiation belt electrons might be directly linked to the spatial and temporal variations of Very Low Frequency/Extremely Low Frequency (VLF/ELF) ionospheric exit point. Hence this research will focus on studying VLF/ELF chorus characteristics at frequencies of 0.003-30kHz with the objective of locating their ionospheric exit point. During February 17 - 25, 2012, the VLF-CHAIN campaign observed VLF/ELF emissions at subauroral latitudes using two loop antennas at Athabasca (MLAT=61.31, L=4.3) and Fort Vermillion (MLAT=64.51, L=5.4), Canada. Since the end of this campaign, continuous measurements of VLF/ELF waves with a sampling rate of 100 kHz, have been made at Athabasca. We have developed a polarization and spectral analysis method that has been successfully tested with an artificial wave with known polarization parameters. We intend to apply this process to raw data from both ground stations. The objective is to study the temporal variations of polarization parameters for several types of chorus wave emissions observed during the VLF-CHAIN campaign, such as, quasi-periodic emissions, falling-tone and rising-tone chorus, as well as bursty-patch emissions.

  12. Pc5 geomagnetic pulsations, pulsating particle precipitation, and VLF chorus: Case study on 24 November 2006

    NASA Astrophysics Data System (ADS)

    Manninen, J.; Kleimenova, N. G.; Kozyreva, O. V.; Turunen, T.

    2010-08-01

    The event (24 November 2006, ˜0400-0500 UT) of the simultaneous observations of Pc5 ULF geomagnetic pulsations, electron precipitation (CNA riometer absorption), and whistler-mode chorus, as well as solar wind (SW) and IMF parameters have been analyzed based on the data from IMAGE magnetometers, Finnish riometer array, and temporal VLF station. The visible correlation between the simultaneous occurrence of several minutes scale patches of chorus and pulsating CNA enhancements was found. The dynamic spectra of the riometer data showed a maximum at ˜3.5 mHz in the first half-hour interval and at ˜2.0 mHz in the second one, while the ULF pulsation spectra exhibit these two maxima in both intervals simultaneously. In the first time interval, the Pc5 pulsations at ˜3.5 mHz demonstrated the typical FLR feature. The SW dynamic pressure fluctuations showed a broad (1.5-3.5 mHz) spectral maximum in the first interval; however, in the second one, the simultaneous oscillations at ˜2.0 mHz were observed in SW pressure and in IMF Bz. The similar ˜2.0 mHz peak has been found in the spectra of Pc5 pulsations from auroral zone to the equator, in riometer absorption, and in VLF chorus power. We suggest that the modulation of particle precipitation and whistler-mode chorus patches was caused by the 2.0 mHz compressional component of Pc5 poloidal geomagnetic pulsations driven in the magnetosphere by SW dynamic pressure and IMF Bz disturbances.

  13. Wave normal angles of whistler mode chorus rising and falling tones

    NASA Astrophysics Data System (ADS)

    Taubenschuss, Ulrich; Khotyaintsev, Yuri V.; Santolík, Ondrej; Vaivads, Andris; Cully, Christopher M.; Contel, Olivier Le; Angelopoulos, Vassilis

    2014-12-01

    We present a study of wave normal angles (θk) of whistler mode chorus emission as observed by Time History of Events and Macroscale Interactions during Substorms (THEMIS) during the year 2008. The three inner THEMIS satellites THA, THD, and THE usually orbit Earth close to the dipole magnetic equator (±20°), covering a large range of L shells from the plasmasphere out to the magnetopause. Waveform measurements of electric and magnetic fields enable a detailed polarization analysis of chorus below 4 kHz. When displayed in a frequency-θk histogram, four characteristic regions of occurrence are evident. They are separated by gaps at f/fc,e≈0.5 (f is the chorus frequency, fc,e is the local electron cyclotron frequency) and at θk˜40°. Below θk˜40°, the average value for θk is predominantly field aligned, but slightly increasing with frequency toward half of fc,e (θk up to 20°). Above half of fc,e, the average θk is again decreasing with frequency. Above θk˜40°, wave normal angles are usually close to the resonance cone angle. Furthermore, we present a detailed comparison of electric and magnetic fields of chorus rising and falling tones. Falling tones exhibit peaks in occurrence solely for θk>40° and are propagating close to the resonance cone angle. Nevertheless, when comparing rising tones to falling tones at θk>40°, the ratio of magnetic to electric field shows no significant differences. Thus, we conclude that falling tones are generated under similar conditions as rising tones, with common source regions close to the magnetic equatorial plane.

  14. The role of landscape composition and configuration on Pteropus giganteus roosting ecology and Nipah virus spillover risk in Bangladesh.

    PubMed

    Hahn, Micah B; Gurley, Emily S; Epstein, Jonathan H; Islam, Mohammad S; Patz, Jonathan A; Daszak, Peter; Luby, Stephen P

    2014-02-01

    Nipah virus has caused recurring outbreaks in central and northwest Bangladesh (the "Nipah Belt"). Little is known about roosting behavior of the fruit bat reservoir, Pteropus giganteus, or factors driving spillover. We compared human population density and ecological characteristics of case villages and control villages (no reported outbreaks) to understand their role in P. giganteus roosting ecology and Nipah virus spillover risk. Nipah Belt villages have a higher human population density (P < 0.0001), and forests that are more fragmented than elsewhere in Bangladesh (0.50 versus 0.32 patches/km(2), P < 0.0001). The number of roosts in a village correlates with forest fragmentation (r = 0.22, P = 0.03). Villages with a roost containing Polyalthia longifolia or Bombax ceiba trees were more likely case villages (odds ratio [OR] = 10.8, 95% confidence interval [CI] = 1.3-90.6). This study suggests that, in addition to human population density, composition and structure of the landscape shared by P. giganteus and humans may influence the geographic distribution of Nipah virus spillovers.

  15. The Role of Landscape Composition and Configuration on Pteropus giganteus Roosting Ecology and Nipah Virus Spillover Risk in Bangladesh

    PubMed Central

    Hahn, Micah B.; Gurley, Emily S.; Epstein, Jonathan H.; Islam, Mohammad S.; Patz, Jonathan A.; Daszak, Peter; Luby, Stephen P.

    2014-01-01

    Nipah virus has caused recurring outbreaks in central and northwest Bangladesh (the “Nipah Belt”). Little is known about roosting behavior of the fruit bat reservoir, Pteropus giganteus, or factors driving spillover. We compared human population density and ecological characteristics of case villages and control villages (no reported outbreaks) to understand their role in P. giganteus roosting ecology and Nipah virus spillover risk. Nipah Belt villages have a higher human population density (P < 0.0001), and forests that are more fragmented than elsewhere in Bangladesh (0.50 versus 0.32 patches/km2, P < 0.0001). The number of roosts in a village correlates with forest fragmentation (r = 0.22, P = 0.03). Villages with a roost containing Polyalthia longifolia or Bombax ceiba trees were more likely case villages (odds ratio [OR] = 10.8, 95% confidence interval [CI] = 1.3–90.6). This study suggests that, in addition to human population density, composition and structure of the landscape shared by P. giganteus and humans may influence the geographic distribution of Nipah virus spillovers. PMID:24323516

  16. Chemical composition and antimicrobial activity of Cymbopogon citratus and Cymbopogon giganteus essential oils alone and in combination.

    PubMed

    Bassolé, I H N; Lamien-Meda, A; Bayala, B; Obame, L C; Ilboudo, A J; Franz, C; Novak, J; Nebié, R C; Dicko, M H

    2011-09-15

    As part of ongoing research on the chemical composition and the antimicrobial properties of Burkinabe plants essential oils alone and in combination, essential oils (EOs) from leaves of Cymbopogon citratus and Cymbopogon giganteus from Burkina Faso were analyzed by GC-FID and GC-MS. Five constituents, which accounted for 96.3% of the oil, were identified in the EO of C. citratus. Geranial (48.1%), neral (34.6%) and myrcene (11.0%) were the major constituents. For C. giganteus a total of eight compounds were identified which represented 86.0% of the oils extracted. The dominant compounds were limonene (42%) and a set of monoterpene alcohols: trans-p-mentha-1(7),8-dien-2-ol (14.2%), cis-p-mentha-1(7),8-dien-2-ol (12%), trans-p-mentha-2,8-dien-1-ol (5.6%) and cis-p-mentha-2,8-dien-1-ol (5.2%). The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose.

  17. Nonlinear dynamics of electrons interacting with oblique whistler mode chorus in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Hsieh, Yi-Kai; Omura, Yoshiharu

    2017-01-01

    We perform test particle simulations for relativistic electrons interacting with a whistler mode chorus packet propagating at oblique angles. By confirming that the energy transport of oblique lower band chorus is nearly along the ambient magnetic field, we apply the gyroaveraging method in calculating equations of motion of electrons. We trace evolution of a delta function of relativistic electrons in a phase space of kinetic energy and equatorial pitch angle and obtain numerical Green's functions of the chorus wave-particle interactions. Examining the Green's functions in a wide range of kinetic energies, we find that Landau resonance can accelerate MeV electrons efficiently and that higher nth resonances such as n =- 1 and n = 2 also contribute to acceleration of electrons at high equatorial pitch angles (˜70°) and high energies (˜2 MeV). We investigate the rate of energy gain of the cyclotron resonance acceleration and the Landau resonance acceleration and find that the perpendicular component of wave electric field dominates both accelerations for MeV electrons. Furthermore, the proximity between the parallel components of Vp and Vg of oblique whistler mode waves and the nonlinear trapping condition make the interaction time of Landau resonance much longer than that of n = 1 cyclotron resonance, resulting in efficient acceleration of MeV electrons.

  18. Nonlinear dynamics of electrons interacting with oblique whistler-mode chorus in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Hsieh, Y.; Omura, Y.

    2016-12-01

    We perform test particle simulations for relativistic electrons interacting with a whistler mode chorus packet propagating at oblique angles. By confirming that the energy transport of oblique lower-band chorus is nearly along the ambient magnetic field, we apply the gyro-averaging method in calculating equations of motion of electrons. We trace evolution of a delta function of relativistic electrons in a phase space of kinetic energy and equatorial pitch angle, and obtain numerical Green's functions of the chorus wave particle interactions. Examining the Green's functions in a wide range of kinetic energies, we find that Landau resonance can accelerate MeV electrons efficiently, and that higher n-th resonances such as n = -1 and n = 2 also contribute to acceleration of electrons at high equatorial pitch angles ( 70° ) and high energies ( 2 MeV). We investigate the rate of energy gain of the cyclotron resonance acceleration and the Landau resonance acceleration, and find that the perpendicular component of wave electric field dominates both accelerations for MeV electrons. Furthermore, the proximity between Vp and Vg of oblique whistler-mode waves and the nonlinear trapping condition make the interaction time of Landau resonance much longer than that of n = 1 cyclotron resonance, resulting in efficient acceleration of MeV electrons.

  19. Self-to-other ratios measured in an opera chorus in performance

    NASA Astrophysics Data System (ADS)

    Ternström, Sten; Cabrera, Densil; Davis, Pamela

    2005-12-01

    Four volunteer members of the chorus of Opera Australia, representing four different voice categories, wore binaural pairs of wireless microphones during a penultimate dress rehearsal on the Opera Theater stage of the Sydney Opera House. From the recordings, data were obtained on sound levels and on the self-to-other ratios (SORs). The sound levels were comparable to those found in loud music in chamber choir performance. The average SOR ranged from +10 to +15 dB. Compared to chamber choirs in other types of room, the SOR values were high. On a separate occasion, the stage support parameters ST1 (early reflections) and ST2 (late reflections) were measured over the whole stage area. ST1 was about -16 dB, which is typical for opera stages, and -20 dB for ST2, which is unusually low. It is concluded that the SOR in the opera chorus depends mostly on choir formation, which is highly variable, and that an opera chorus artist generally can hear his or her own voice very well, but little of the others and of the orchestra. This was confirmed by informal listening to the recordings.

  20. Self-to-other ratios measured in an opera chorus in performance.

    PubMed

    Ternström, Sten; Cabrera, Densil; Davis, Pamela

    2005-12-01

    Four volunteer members of the chorus of Opera Australia, representing four different voice categories, wore binaural pairs of wireless microphones during a penultimate dress rehearsal on the Opera Theater stage of the Sydney Opera House. From the recordings, data were obtained on sound levels and on the self-to-other ratios (SORs). The sound levels were comparable to those found in loud music in chamber choir performance. The average SOR ranged from +10 to +15 dB. Compared to chamber choirs in other types of room, the SOR values were high. On a separate occasion, the stage support parameters ST1 (early reflections) and ST2 (late reflections) were measured over the whole stage area. ST1 was about -16 dB, which is typical for opera stages, and -20 dB for ST2, which is unusually low. It is concluded that the SOR in the opera chorus depends mostly on choir formation, which is highly variable, and that an opera chorus artist generally can hear his or her own voice very well, but little of the others and of the orchestra. This was confirmed by informal listening to the recordings.

  1. Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus.

    PubMed

    Thorne, R M; Li, W; Ni, B; Ma, Q; Bortnik, J; Chen, L; Baker, D N; Spence, H E; Reeves, G D; Henderson, M G; Kletzing, C A; Kurth, W S; Hospodarsky, G B; Blake, J B; Fennell, J F; Claudepierre, S G; Kanekal, S G

    2013-12-19

    Recent analysis of satellite data obtained during the 9 October 2012 geomagnetic storm identified the development of peaks in electron phase space density, which are compelling evidence for local electron acceleration in the heart of the outer radiation belt, but are inconsistent with acceleration by inward radial diffusive transport. However, the precise physical mechanism responsible for the acceleration on 9 October was not identified. Previous modelling has indicated that a magnetospheric electromagnetic emission known as chorus could be a potential candidate for local electron acceleration, but a definitive resolution of the importance of chorus for radiation-belt acceleration was not possible because of limitations in the energy range and resolution of previous electron observations and the lack of a dynamic global wave model. Here we report high-resolution electron observations obtained during the 9 October storm and demonstrate, using a two-dimensional simulation performed with a recently developed time-varying data-driven model, that chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase. Our detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt, and the results presented have potential application to Jupiter, Saturn and other magnetized astrophysical objects.

  2. Plant and soil effects on bacterial communities associated with Miscanthus  ×  giganteus rhizosphere and rhizomes

    SciTech Connect

    Li, Dongfang; Voigt, Thomas B.; Kent, Angela D.

    2015-02-11

    Here, bacterial assemblages, especially diazotroph assemblages residing in the rhizomes and the rhizosphere soil of Miscanthus × giganteus, contribute to plant growth and nitrogen use efficiency. However, the composition of these microbial communities has not been adequately explored nor have the potential ecological drivers for these communities been sufficiently studied. This knowledge is needed for understanding and potentially improving M. × giganteus – microbe interactions, and further enhancing sustainability of M. × giganteus production. In this study, cultivated M. × giganteus from four sites in Illinois, Kentucky, Nebraska, and New Jersey were collected to examine the relative influences of soil conditions and plant compartments on assembly of the M. × giganteus-associated microbiome. Automated ribosomal intergenic spacer (ARISA) and terminal restriction fragment length polymorphism (T-RFLP) targeting the nifH gene were applied to examine the total bacterial communities and diazotroph assemblages that reside in the rhizomes and the rhizosphere. Distinct microbial assemblages were detected in the endophytic and rhizosphere compartments. Site soil conditions had strong correlation with both total bacterial and diazotroph assemblages, but in different ways. Nitrogen treatments showed no significant effect on the composition of diazotroph assemblages in most sites. Endophytic compartments of different M. × giganteus plants tended to harbor similar microbial communities across all sites, whereas the rhizosphere soil of different plant tended to harbor diverse microbial assemblages that were distinct among sites. These observations offer insight into better understanding of the associative interactions between M. × giganteus and diazotrophs, and how this relationship is influenced by agronomic and edaphic factors.

  3. Electron hybrid simulations of whistler-mode chorus generation with real parameters in the Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Katoh, Y.; Omura, Y.

    2016-12-01

    Whistler-mode chorus emissions play curial roles in the evolution of radiation belt electrons. Chorus emissions are narrow band emissions observed in the typical frequency range of 0.2 to 0.8 fce0 with a gap at half the fce0, where fce0 represents the electron gyrofrequency at the magnetic equator. The generation process of chorus has been explained by the nonlinear wave growth theory [see review by Omura et al., in AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere, 2012] and has been reproduced by self-consistent numerical experiments [e.g., Katoh and Omura, GRL 2007, JGR 2011, 2013]. In the present study, we show the result of electron hybrid simulation of the generation process of whistler-mode chorus emissions under realistic initial conditions. We refer in-situ observations by Cluster [Santolik et al., 2003] for the initial parameters of energetic electrons and the spatial inhomogeneity of the background magnetic field. In the simulation results we observe chorus emissions with rising tones whose the spectral characteristics are consistent with the observation. We also find that the simulation results are consistently explained by the theoretically estimated threshold and optimum wave amplitudes of chorus elements based on the nonlinear wave growth theory. A series of simulations reveal properties of the chorus generation depending on the velocity distribution of energetic electrons [Katoh and Omura, JGR 2011] and the background magnetic field inhomogeneity [Katoh and Omura, JGR 2013]. These properties should be evaluated by comparison with in-situ and ground-based observations.

  4. The relationship between the macroscopic state of electrons and the properties of chorus waves observed by the Van Allen Probes

    SciTech Connect

    Yue, Chao; An, Xin; Bortnik, Jacob; Ma, Qianli; Li, Wen; Thorne, Richard M.; Reeves, Geoffrey D.; Gkioulidou, Matina; Mitchell, Donald G.; Kletzing, Craig A.

    2016-08-04

    Plasma kinetic theory predicts that a sufficiently anisotropic electron distribution will excite whistler mode waves, which in turn relax the electron distribution in such a way as to create an upper bound on the relaxed electron anisotropy. Here using whistler mode chorus wave and plasma measurements by Van Allen Probes, we confirm that the electron distributions are well constrained by this instability to a marginally stable state in the whistler mode chorus waves generation region. Lower band chorus waves are organized by the electron β∥e into two distinct groups: (i) relatively large-amplitude, quasi-parallel waves with β∥e ≳0:025 and (ii) relatively small-amplitude, oblique waves with β∥e ≲0:025. The upper band chorus waves also have enhanced amplitudes close to the instability threshold, with large-amplitude waves being quasi-parallel whereas small-amplitude waves being oblique. These results provide important insight for studying the excitation of whistler mode chorus waves.

  5. The relationship between the macroscopic state of electrons and the properties of chorus waves observed by the Van Allen Probes

    DOE PAGES

    Yue, Chao; An, Xin; Bortnik, Jacob; ...

    2016-08-04

    Plasma kinetic theory predicts that a sufficiently anisotropic electron distribution will excite whistler mode waves, which in turn relax the electron distribution in such a way as to create an upper bound on the relaxed electron anisotropy. Here using whistler mode chorus wave and plasma measurements by Van Allen Probes, we confirm that the electron distributions are well constrained by this instability to a marginally stable state in the whistler mode chorus waves generation region. Lower band chorus waves are organized by the electron β∥e into two distinct groups: (i) relatively large-amplitude, quasi-parallel waves with β∥e ≳0:025 and (ii) relativelymore » small-amplitude, oblique waves with β∥e ≲0:025. The upper band chorus waves also have enhanced amplitudes close to the instability threshold, with large-amplitude waves being quasi-parallel whereas small-amplitude waves being oblique. These results provide important insight for studying the excitation of whistler mode chorus waves.« less

  6. The relationship between the macroscopic state of electrons and the properties of chorus waves observed by the Van Allen Probes

    SciTech Connect

    Yue, Chao; An, Xin; Bortnik, Jacob; Ma, Qianli; Li, Wen; Thorne, Richard M.; Reeves, Geoffrey D.; Gkioulidou, Matina; Mitchell, Donald G.; Kletzing, Craig A.

    2016-08-04

    Plasma kinetic theory predicts that a sufficiently anisotropic electron distribution will excite whistler mode waves, which in turn relax the electron distribution in such a way as to create an upper bound on the relaxed electron anisotropy. Here using whistler mode chorus wave and plasma measurements by Van Allen Probes, we confirm that the electron distributions are well constrained by this instability to a marginally stable state in the whistler mode chorus waves generation region. Lower band chorus waves are organized by the electron β∥e into two distinct groups: (i) relatively large-amplitude, quasi-parallel waves with β∥e ≳0:025 and (ii) relatively small-amplitude, oblique waves with β∥e ≲0:025. The upper band chorus waves also have enhanced amplitudes close to the instability threshold, with large-amplitude waves being quasi-parallel whereas small-amplitude waves being oblique. These results provide important insight for studying the excitation of whistler mode chorus waves.

  7. Observation of chorus waves by the Van Allen Probes: dependence on solar wind parameters and scale size

    NASA Astrophysics Data System (ADS)

    Aryan, H.; Sibeck, D. G.; Balikhin, M. A.; Agapitov, O. V.; Kletzing, C.

    2016-12-01

    Highly energetic electrons in the Earth's Van Allen radiation belts can cause serious damage to spacecraft electronic systems, and affect the atmospheric composition if they precipitate into the upper atmosphere. Whistler mode chorus waves have attracted significant attention in recent decades for their crucial role in the acceleration and loss of energetic electrons that ultimately change the dynamics of the radiation belts. The distribution of these waves in the inner magnetosphere is commonly presented as a function of geomagnetic activity. However, geomagnetic indices are non-specific parameters that are compiled from imperfectly covered ground based measurements. The present study uses wave data from the two Van Allen Probes to present the distribution of lower band chorus waves not only as functions of single geomagnetic index and solar wind parameters, but also as functions of combined parameters. Also the current study takes advantage of the unique equatorial orbit of the Van Allen Probes to estimate the average scale size of chorus wave packets, during close separations between the two spacecraft, as a function of radial distance, magnetic latitude, and geomagnetic activity respectively. Results show that the average scale size of chorus wave packets is approximately 1300 - 2300 km. The results also show that the inclusion of combined parameters can provide better representation of the chorus wave distributions in the inner magnetosphere, and therefore can further improve our knowledge of the acceleration and loss of radiation belt electrons.

  8. Observation of chorus waves by the Van Allen Probes: Dependence on solar wind parameters and scale size

    NASA Astrophysics Data System (ADS)

    Aryan, Homayon; Sibeck, David; Balikhin, Michael; Agapitov, Oleksiy; Kletzing, Craig

    2016-08-01

    Highly energetic electrons in the Earth's Van Allen radiation belts can cause serious damage to spacecraft electronic systems and affect the atmospheric composition if they precipitate into the upper atmosphere. Whistler mode chorus waves have attracted significant attention in recent decades for their crucial role in the acceleration and loss of energetic electrons that ultimately change the dynamics of the radiation belts. The distribution of these waves in the inner magnetosphere is commonly presented as a function of geomagnetic activity. However, geomagnetic indices are nonspecific parameters that are compiled from imperfectly covered ground based measurements. The present study uses wave data from the two Van Allen Probes to present the distribution of lower band chorus waves not only as functions of single geomagnetic index and solar wind parameters but also as functions of combined parameters. Also the current study takes advantage of the unique equatorial orbit of the Van Allen Probes to estimate the average scale size of chorus wave packets, during close separations between the two spacecraft, as a function of radial distance, magnetic latitude, and geomagnetic activity, respectively. Results show that the average scale size of chorus wave packets is approximately 1300-2300 km. The results also show that the inclusion of combined parameters can provide better representation of the chorus wave distributions in the inner magnetosphere and therefore can further improve our knowledge of the acceleration and loss of radiation belt electrons.

  9. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations.

    PubMed

    Fu, Xiangrong; Cowee, Misa M; Friedel, Reinhard H; Funsten, Herbert O; Gary, S Peter; Hospodarsky, George B; Kletzing, Craig; Kurth, William; Larsen, Brian A; Liu, Kaijun; MacDonald, Elizabeth A; Min, Kyungguk; Reeves, Geoffrey D; Skoug, Ruth M; Winske, Dan

    2014-10-01

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr <Ω e , where Ω e is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃Ω e /2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ∼Ω e /2 is a natural consequence of the growth of two whistler modes with different properties.

  10. Observation of Chorus Waves by the Van Allen Probes: Dependence on Solar Wind Parameters and Scale Size

    NASA Technical Reports Server (NTRS)

    Aryan, Homayon; Sibeck, David; Balikhin, Michael; Agapitov, Oleksiy; Kletzing, Craig

    2016-01-01

    Highly energetic electrons in the Earths Van Allen radiation belts can cause serious damage to spacecraft electronic systems and affect the atmospheric composition if they precipitate into the upper atmosphere. Whistler mode chorus waves have attracted significant attention in recent decades for their crucial role in the acceleration and loss of energetic electrons that ultimately change the dynamics of the radiation belts. The distribution of these waves in the inner magnetosphere is commonly presented as a function of geomagnetic activity. However, geomagnetic indices are nonspecific parameters that are compiled from imperfectly covered ground based measurements. The present study uses wave data from the two Van Allen Probes to present the distribution of lower band chorus waves not only as functions of single geomagnetic index and solar wind parameters but also as functions of combined parameters. Also the current study takes advantage of the unique equatorial orbit of the Van Allen Probes to estimate the average scale size of chorus wave packets, during close separations between the two spacecraft, as a function of radial distance, magnetic latitude, and geomagnetic activity, respectively. Results show that the average scale size of chorus wave packets is approximately 13002300 km. The results also show that the inclusion of combined parameters can provide better representation of the chorus wave distributions in the inner magnetosphere and therefore can further improve our knowledge of the acceleration and loss of radiation belt electrons.

  11. The relationship between the macroscopic state of electrons and the properties of chorus waves observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Yue, Chao; An, Xin; Bortnik, Jacob; Ma, Qianli; Li, Wen; Thorne, Richard M.; Reeves, Geoffrey D.; Gkioulidou, Matina; Mitchell, Donald G.; Kletzing, Craig A.

    2016-08-01

    Plasma kinetic theory predicts that a sufficiently anisotropic electron distribution will excite whistler mode waves, which in turn relax the electron distribution in such a way as to create an upper bound on the relaxed electron anisotropy. Here using whistler mode chorus wave and plasma measurements by Van Allen Probes, we confirm that the electron distributions are well constrained by this instability to a marginally stable state in the whistler mode chorus waves generation region. Lower band chorus waves are organized by the electron β∥e into two distinct groups: (i) relatively large-amplitude, quasi-parallel waves with β∥e≳0.025 and (ii) relatively small-amplitude, oblique waves with β∥e≲0.025. The upper band chorus waves also have enhanced amplitudes close to the instability threshold, with large-amplitude waves being quasi-parallel whereas small-amplitude waves being oblique. These results provide important insight for studying the excitation of whistler mode chorus waves.

  12. Determination of solar cycle variations of midlatitude ELF/VLF chorus and hiss via automated signal detection

    NASA Astrophysics Data System (ADS)

    Golden, D. I.; Spasojevic, M.; Inan, U. S.

    2011-03-01

    An automated algorithm for detecting chorus and hiss emissions in ground-based extremely low frequency/very low frequency (ELF/VLF) wave receiver data is developed and applied to 10 years of data collected at Palmer Station, Antarctica (L = 2.4, 50°S invariant latitude). The algorithm consists of three major processing steps. First, sferics and power line hum are removed from the broadband data. Second, individual events are detected and a set of 19 scalar event parameters are determined. Finally, on the basis of the parameters, detected events are categorized by a sequential pair of neural networks as either chorus, hiss, or noise. The detector runs on a modern 8-core computer at a speed of 350x real time. Results of training indicate that the neural networks are capable of differentiating between noise and emissions with a 92% success rate and between chorus and hiss with an 84% success rate. Data collected at Palmer from May 2000 to May 2010 were processed, and yearly and seasonal trends of chorus and hiss are analyzed. Yearly occurrence rates of chorus and hiss are strongly dependent on the geomagnetic disturbance level, as measured by Kp and AE, whereas seasonal occurrence rates are more strongly dependent on variations of the day/night terminator and associated variations in ionospheric absorption.

  13. Generation of banded chorus by a two-component energetic electron distribution in an inhomogeneous magnetic field

    NASA Astrophysics Data System (ADS)

    Huang, H.; Wang, Z. B.; Tao, X.; Wang, X. G.

    2017-10-01

    The generation of banded chorus by a two-component energetic electron distribution in a mirror-like inhomogeneous magnetic field is investigated in this work by a 1D hybrid code DAWN. A previous study by Liu et al. [Geophys. Res. Lett. 38, L14108 (2011)] suggested that banded chorus waves can be independently generated by two energetic electron populations. In this work, we first conduct a series of simulations to confirm that the starting frequency of chorus elements is close to the frequency of maximum linear growth rate. With carefully chosen simulation parameters, we then successfully generate banded chorus with a gap near half the electron gyrofrequency. By expanding the parameter range, however, we demonstrate that the gap can be located at frequencies other than the half electron gyrofrequency. We conclude that though the previous mechanism proposed by Liu et al. [Geophys. Res. Lett. 38, L14108 (2011)] can explain the relative independence of upper band and lower band chorus, further work is needed to explain why the linear properties of energetic electrons in the magnetosphere should produce a gap at 0.5Ωe0.

  14. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations

    NASA Astrophysics Data System (ADS)

    Fu, Xiangrong; Cowee, Misa M.; Friedel, Reinhard H.; Funsten, Herbert O.; Gary, S. Peter; Hospodarsky, George B.; Kletzing, Craig; Kurth, William; Larsen, Brian A.; Liu, Kaijun; MacDonald, Elizabeth A.; Min, Kyungguk; Reeves, Geoffrey D.; Skoug, Ruth M.; Winske, Dan

    2014-10-01

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr<Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr≃Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ˜Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

  15. Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

    NASA Astrophysics Data System (ADS)

    Gary, S. Peter; Fu, Xiangrong; Cowee, Misa M.; Friedel, Reinhard H.; Funsten, Herbert O.; Hospodarsky, George B.; Kletzing, Craig; Kurth, William; Larsen, Brian A.; Liu, Kaijun; MacDonald, Elizabeth A.; Min, Kyungguk; Reeves, Geoffrey D.; Skoug, Ruth M.; Winske, Dan

    2014-10-01

    Magnetospheric banded chorus events are enhanced whistler waves with frequencies ωr <Ωe where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ~=Ωe / 2 . Here two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma test the hypothesis that banded chorus is due to two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. Observations show a three-component electron model consisting of a dense, cold (a few tens of eV) population, a less dense, warm (a few hundred eV) anisotropic population, and a still less dense, hot (a few keV) anisotropic population. Simulations show that the warm component drives quasi-electrostatic upper-band chorus, and the hot component drives electromagnetic lower-band chorus; the gap near Ωe / 2 follows from growth of the two distinct instabilities.

  16. In Vitro Fermentation of Xylooligosaccharides Produced from Miscanthus × giganteus by Human Fecal Microbiota.

    PubMed

    Chen, Ming-Hsu; Swanson, Kelly S; Fahey, George C; Dien, Bruce S; Beloshapka, Alison N; Bauer, Laura L; Rausch, Kent D; Tumbleson, M E; Singh, Vijay

    2016-01-13

    Purified xylooligosaccharides from Miscanthus × giganteus (M×G XOS) were used in an in vitro fermentation experiment inoculated with human fecal microbiota. A commercial XOS product and pectin were used as controls. Decreases in pH by 2.3, 2.4, and 2.0 units and production of short-chain fatty acids (SCFA; acetic acid, 7764.2, 6664.1, and 6387.9 μmol/g; propionic acid, 1006.7, 1089.5, and 661.5 μmol/g; and butyric acid, 955.5, 1252.9, and 917.7 μmol/g) were observed in M×G XOS, commercial XOS, and pectin medium after 12 h of fermentation, respectively. Titers of Bifidobacterium spp., Lactobacillus spp., and Escherichia coli increased when fed all three substrates as monitored by qPCR. There was no significant trend for Clostridium perfringens. During fermentation, M×G XOS was statistically equivalent in performance to the commercial XOS sample as measured by culture acidification and growth of health-promoting bacteria and resulted in the highest SCFA production among the three substrates.

  17. Anthelmintic Treatment Does Not Change Foraging Strategies of Female Eastern Grey Kangaroos, Macropus giganteus

    PubMed Central

    Cripps, Jemma K.; Martin, Jennifer K.; Coulson, Graeme

    2016-01-01

    Large mammalian herbivores are commonly infected with gastrointestinal helminths. Heavily parasitised hosts are likely to have increased nutritional requirements and would be predicted to increase their food intake to compensate for costs of being parasitised, but experimental tests of the impacts of these parasites on the foraging efficiency of hosts are lacking, particularly in free-ranging wildlife. We conducted a field experiment on a population of free-ranging eastern grey kangaroos (Macropus giganteus) to test this prediction, removing nematodes from one group of adult females using an anthelmintic treatment. We then carried out observations before and following treatment to assess the influence of parasites on foraging behaviour. Contrary to our predictions, the manipulation of parasite burdens did not result in changes in any of the key foraging variables we measured. Our results suggest that despite carrying large burdens of gastrointestinal parasites, the foraging strategy of female kangaroos is likely be driven by factors unrelated to parasitism, and that kangaroos in high nutritional environments may be able acquire sufficient nutrients to offset the costs of parasitism. We conclude that the drivers of forage intake likely differ between domesticated and free-ranging herbivores, and that free-ranging hosts are likely more resilient to parasitism. PMID:26784582

  18. Dominance, body size and internal relatedness influence male reproductive success in eastern grey kangaroos (Macropus giganteus).

    PubMed

    Miller, Emily J; Eldridge, Mark D B; Cooper, Desmond W; Herbert, Catherine A

    2010-01-01

    Knowledge of the determinants of reproductive success is essential for understanding the adaptive significance of particular traits. The present study examined whether particular behavioural, morphological, physiological or genetic traits were correlated with male dominance and reproductive success using three semi-free-ranging captive populations (n = 98) of the eastern grey kangaroo (Macropus giganteus). The morphological traits measured included bodyweight, head, forearm, tail, pes and leg length, forearm and bicep circumference, and testis size. Blood samples were collected to determine serum testosterone concentrations. All individuals were typed for 10 microsatellite loci and paternity determined for each pouch young. To determine the influence of relatedness and genetic diversity on male reproductive success, internal relatedness, standardised heterozygosity and mean d(2) were calculated. Dominant males sired a significantly higher proportion of offspring than smaller, lower-ranked males and had higher testosterone concentrations. Males that sired offspring were significantly heavier and had larger body size. Sires were significantly more heterozygous and genetically dissimilar to breeding females than non-sires. Despite the wealth of knowledge on the social organisation of kangaroos, this is the first study to assign parentage and male reproductive success using molecular evidence.

  19. Phylogeography of Eastern Grey Kangaroos, Macropus giganteus, Suggests a Mesic Refugium in Eastern Australia

    PubMed Central

    2015-01-01

    Phylogeographic studies around the world have identified refugia where fauna were able to persist during unsuitable climatic periods, particularly during times of glaciation. In Australia the effects of Pleistocene climate oscillations on rainforest taxa have been well studied but less is known about the effects on mesic-habitat fauna, such as the eastern grey kangaroo (Macropus giganteus). The eastern grey kangaroo is a large mammal that is common and widespread throughout eastern Australia, preferring dry mesic habitat, rather than rainforest. As pollen evidence suggests that the central-eastern part of Australia (southeast Queensland and northern New South Wales) experienced cycles of expansion in mesic habitat with contraction in rainforests, and vice versa during glacial and interglacial periods, respectively, we hypothesise that the distribution of the eastern grey kangaroo was affected by these climate oscillations and may have contracted to mesic habitat refugia. From 375 mitochondrial DNA control region sequences from across the distribution of eastern grey kangaroos we obtained 108 unique haplotypes. Phylogenetic analysis identified two clades in Queensland, one of which is newly identified and restricted to a small coastal region in southern Queensland north of Brisbane, known as the Sunshine Coast. The relatively limited geographic range of this genetically isolated clade suggests the possibility of a mesic habitat refugium forming during rainforest expansion during wetter climate cycles. Other potential, although less likely, reasons for the genetic isolation of the highly distinct clade include geographic barriers, separate northward expansions, and strong local adaptation. PMID:26024370

  20. Cutaneous and diphtheritic avian poxvirus infection in a nestling Southern Giant Petrel (Macronectes giganteus) from Antarctica

    USGS Publications Warehouse

    Shearn-Bochsler, Valerie; Green, David Earl; Converse, K.A.; Docherty, D.E.; Thiel, T.; Geisz, H.N.; Fraser, William R.; Patterson-Fraser, Donna L.

    2008-01-01

    The Southern giant petrel (Macronectes giganteus) is declining over much of its range and currently is listed as vulnerable to extinction by the International Union for the Conservation of Nature (IUCN). Island-specific breeding colonies near Palmer Station, Antarctica, have been monitored for over 30 years, and because this population continues to increase, it is critically important to conservation. In austral summer 2004, six diseased giant petrel chicks were observed in four of these colonies. Diseased chicks were 6a??9 weeks old and had multiple proliferative nodules on their bills and skin. One severely affected chick was found dead on the nest and was salvaged for necropsy. Histopathological examination of nodules from the dead chick revealed epithelial cell hyperplasia and hypertrophy with numerous eosinophilic intracytoplasmic inclusions (B??llinger bodies). A poxvirus was isolated from multiple nodules. Poxviral infection has not been reported in this species, and the reason for its emergence and its potential impact on the population are not yet known.

  1. Spatio-Temporal Variation of Core and Satellite Arbuscular Mycorrhizal Fungus Communities in Miscanthus giganteus.

    PubMed

    Barnes, Christopher J; Burns, Caitlin A; van der Gast, Christopher J; McNamara, Niall P; Bending, Gary D

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are a group of obligate plant symbionts which can promote plant nutrition. AMF communities are diverse, but the factors which control their assembly in space and time remain unclear. In this study, the contributions of geographical distance, environmental heterogeneity and time in shaping AMF communities associated with Miscanthus giganteus (a perennial grass originating from south-east Asia) were determined over a 13 months period. In particular, the community was partitioned into core (abundant and persistent taxa) and satellite (taxa with low abundance and persistence) constituents and the drivers of community assembly for each determined. β-diversity was exceptionally low across the 140 m line transects, and there was limited evidence of geographical scaling effects on the composition of the core, satellite or combined communities. However, AMF richness and community composition changed over time associated with fluctuation within both the core and satellite communities. The degree to which AMF community variation was explained by soil properties was consistently higher in the core community than the combined and satellite communities, suggesting that the satellite community had considerable stochasticity associated with it. We suggest that the partitioning of communities into their core and satellite constituents could be employed to enhance the variation explained within microbial community analyses.

  2. Gasification of torrefied Miscanthus × giganteus in an air-blown bubbling fluidized bed gasifier.

    PubMed

    Xue, G; Kwapinska, M; Horvat, A; Kwapinski, W; Rabou, L P L M; Dooley, S; Czajka, K M; Leahy, J J

    2014-05-01

    Torrefaction is suggested to be an effective method to improve the fuel properties of biomass and gasification of torrefied biomass should provide a higher quality product gas than that from unprocessed biomass. In this study, both raw and torrefied Miscanthus × giganteus (M×G) were gasified in an air-blown bubbling fluidized bed (BFB) gasifier using olivine as the bed material. The effects of equivalence ratio (ER) (0.18-0.32) and bed temperature (660-850°C) on the gasification performance were investigated. The results obtained suggest the optimum gasification conditions for the torrefied M × G are ER 0.21 and 800°C. The product gas from these process conditions had a higher heating value (HHV) of 6.70 MJ/m(3), gas yield 2m(3)/kg biomass (H2 8.6%, CO 16.4% and CH4 4.4%) and cold gas efficiency 62.7%. The comparison between raw and torrefied M × G indicates that the torrefied M × G is more suitable BFB gasification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Spatio-Temporal Variation of Core and Satellite Arbuscular Mycorrhizal Fungus Communities in Miscanthus giganteus

    PubMed Central

    Barnes, Christopher J.; Burns, Caitlin A.; van der Gast, Christopher J.; McNamara, Niall P.; Bending, Gary D.

    2016-01-01

    Arbuscular mycorrhizal fungi (AMF) are a group of obligate plant symbionts which can promote plant nutrition. AMF communities are diverse, but the factors which control their assembly in space and time remain unclear. In this study, the contributions of geographical distance, environmental heterogeneity and time in shaping AMF communities associated with Miscanthus giganteus (a perennial grass originating from south-east Asia) were determined over a 13 months period. In particular, the community was partitioned into core (abundant and persistent taxa) and satellite (taxa with low abundance and persistence) constituents and the drivers of community assembly for each determined. β-diversity was exceptionally low across the 140 m line transects, and there was limited evidence of geographical scaling effects on the composition of the core, satellite or combined communities. However, AMF richness and community composition changed over time associated with fluctuation within both the core and satellite communities. The degree to which AMF community variation was explained by soil properties was consistently higher in the core community than the combined and satellite communities, suggesting that the satellite community had considerable stochasticity associated with it. We suggest that the partitioning of communities into their core and satellite constituents could be employed to enhance the variation explained within microbial community analyses. PMID:27597844

  4. Ultralong Cycle Life Achieved by a Natural Plant: Miscanthus × giganteus for Lithium Oxygen Batteries.

    PubMed

    Li, Shu; Bi, Xuanxuan; Tao, Ran; Wang, Qingzhen; Yao, Ying; Wu, Feng; Zhang, Cunzhong

    2017-02-08

    Large energy-storage systems and electric vehicles require energy devices with high power and high energy density. Lithium oxygen (Li-O2) batteries could achieve high energy density, but they are still facing problems such as low practical capacity and poor cyclability. Here, we prepare activated carbons (MGACs) based on the natural plant Miscanthus × giganteus (MG) through slow pyrolysis. It possesses a large surface area, plenty of active sites, and high porosity, which are beneficial to the utilization of oxygen electrode in Li-O2 batteries. The MGACs-based oxygen electrode delivers a high specific capacity of 9400 mAh/g at 0.02 mA/cm(2), and long cycle life of 601 cycles (with a cutoff capacity of 500 mAh/g) and 295 cycles (with a cutoff capacity of 1000 mAh/g) at 0.2 mA/cm(2), respectively. Additionally, the material exhibits high rate capability and high reversibility, which is a promising candidate for the application in Li-O2 batteries.

  5. Structural characterization and antioxidant activity of a glucan from Meripilus giganteus.

    PubMed

    Maity, Prasenjit; Nandi, Ashis K; Manna, Dilip K; Pattanayak, Manabendra; Sen, Ipsita K; Bhanja, Sunil K; Samanta, Surajit; Panda, Bibhash C; Paloi, Soumitra; Acharya, Krishnendu; Islam, Syed S

    2017-02-10

    A new water soluble glucan (MGPS), with a molecular weight ∼1.48×10(5)Da, was isolated from the fruit bodies of Meripilus giganteus by hot water extraction followed by purification through dialysis tubing cellulose membrane and sepharose 6B column chromatography. Its structural characteristics were investigated by acid hydrolysis, methylation analysis, Smith degradation and 1D/2D NMR experiments. The monosaccharide composition analysis showed that MGPS contain only glucose. The backbone of MGPS was composed of two (1→3)-β-d-glucopyranosyl, two (1→6)-β-d-glucopyranosyl, two (1→6)-α-d-glucopyranosyl, and one (1→4)-α-d-glucopyranosyl residues, out of which one (1→3)-β-d-glucopyranosyl residue was branched at O-6 position with terminal α-d-glucopyranosyl residue and one (1→4)-α-d-glucopyranosyl residue branched at O-6 position with terminal β-d-glucopyranosyl residue. In vitro antioxidant studies showed that the MGPS exhibited hydroxide radical scavenging activity (IC50=390μg/mL), superoxide radical scavenging activity (IC50=70μg/mL), and ferrous ion chelating activity (IC50=290μg/mL).

  6. The Antifungal Protein AFP from Aspergillus giganteus Inhibits Chitin Synthesis in Sensitive Fungi▿

    PubMed Central

    Hagen, Silke; Marx, Florentine; Ram, Arthur F.; Meyer, Vera

    2007-01-01

    The antifungal protein AFP from Aspergillus giganteus is highly effective in restricting the growth of major human- and plant-pathogenic filamentous fungi. However, a fundamental prerequisite for the use of AFP as an antifungal drug is a complete understanding of its mode of action. In this study, we performed several analyses focusing on the assumption that the chitin biosynthesis of sensitive fungi is targeted by AFP. Here we show that the N-terminal domain of AFP (amino acids 1 to 33) is sufficient for efficient binding of AFP to chitin but is not adequate for inhibition of the growth of sensitive fungi. AFP susceptibility tests and SYTOX Green uptake experiments with class III and class V chitin synthase mutants of Fusarium oxysporum and Aspergillus oryzae showed that deletions made the fungi less sensitive to AFP and its membrane permeabilization effect. In situ chitin synthase activity assays revealed that chitin synthesis is specifically inhibited by AFP in sensitive fungi, indicating that AFP causes cell wall stress and disturbs cell integrity. Further evidence that there was AFP-induced cell wall stress was obtained by using an Aspergillus niger reporter strain in which the cell wall integrity pathway was strongly induced by AFP. PMID:17277210

  7. Catalytic pyrolysis of miscanthus × giganteus in a spouted bed reactor.

    PubMed

    Du, Shoucheng; Sun, Yijia; Gamliel, David P; Valla, Julia A; Bollas, George M

    2014-10-01

    A conical spouted bed reactor was designed and tested for fast catalytic pyrolysis of miscanthus × giganteus over Zeolite Socony Mobil-5 (ZSM-5) catalyst, in the temperature range of 400-600 °C and catalyst to biomass ratios 1:1-5:1. The effect of operating conditions on the lumped product distribution, bio-oil selectivity and gas composition was investigated. In particular, it was shown that higher temperature favors the production of gas and bio-oil aromatics and results in lower solid and liquid yields. Higher catalyst to biomass ratios increased the gas yield, at the expense of liquid and solid products, while enhancing aromatic selectivity. The separate catalytic effects of ZSM-5 catalyst and its Al2O3 support were studied. The support contributes to increased coke/char formation, due to the uncontrolled spatial distribution and activity of its alumina sites. The presence of ZSM-5 zeolite in the catalyst enhanced the production of aromatics due to its proper pore size distribution and activity.

  8. [Raman Spectra Study on Topochemistry in Miscanthus × giganteus Cell Walls During Dilute Acid Pretreatment].

    PubMed

    He, Chuan; Zhou, Xia; Yao, Chun-li; Xu, Feng

    2015-09-01

    Confocal Raman microspectroscopy (CRM) represents a powerful technique that can provide insights into topochemistry in lignocellulosic biomass cell wall. In this work, CRM was used to explore the impact of dilute acid (DA) pretreatment on the topochemistry of lignin and hydroxycinnamic acid (HCA) in the-fiber cell walls of Miscanthus × giganteus internode. Raman spectra extracted from different morphological regions of untreated fiber cell walls indicated the heterogeneous concentration of lignin and HCA. There is a companied trend between them, that is, regions where there is the higher lignin concentration have the higher concentration of HCA. When treated with DA, it was found that the intensity of 1600 cm(-1) (lignin) and 1170 cm(-1) (HCA) were decreased, which could be contributed to the partially removal of lignin and HCA. The removal rate in different morphological areas followed the decreasing order: secondary cell wall (SW) > compound middle lamella (CML) > cell corner middle lamella (CCML). The increase of the Raman band intensity ratio (1170/1600) indicated the preferential removal of lignin in the SW and CML as a result of DA pretreatment, while the constant of the ratio meant there is no preference between lignin and HCA in the CCML. The research will provide the deep understanding of the topochemistry of lignin and HCA at sub-cellular level during DA pretreatment, meanwhile, it also expands the application of Raman spectra in the research area of plant cell wall.

  9. A direct link between chorus emissions and pulsating aurora on timescales from milliseconds to minutes: A case study at subauroral latitudes

    DOE PAGES

    Ozaki, Mitsunori; Yagitani, Satoshi; Sawai, Kaoru; ...

    2015-11-27

    A correlation was observed between chorus emissions and pulsating aurora (PA) from observations at Athabasca (L ≈ 4.3) in Canada at 9:00–9:20 UT on 7 February 2013, using an electron multiplying charge-coupled device camera and a VLF loop antenna with sampling rates of 110 Hz and 100 kHz, respectively. Pulsating aurora having a quasiperiodic variation in luminosity and a few hertz modulation was observed together with chorus emissions consisting of a group of successive rising-tone elements. The repetition period and modulation frequency of the PA are in good agreement with those of the modulated chorus. After 9:11 UT, the temporalmore » features of the aurora became aperiodic PA of indistinct modulation. Simultaneously, the rising-tone chorus turned into chorus emissions consisting of numerous rising-tone elements. The equatorial geomagnetic field inhomogeneity calculated using the Tsyganenko 2002 model shows a decreasing trend during the period. This result is consistent with nonlinear wave growth theory having a small geomagnetic field inhomogeneity, which contributes to a decrease in the threshold amplitude to trigger discrete chorus elements. As a result, these observations show a close connection between chorus emissions and PA on timescales from milliseconds for generation of discrete chorus elements on the microphysics of wave-particle interaction to minutes for the variations of the geomagnetic field inhomogeneity related with the substorm activity.« less

  10. A direct link between chorus emissions and pulsating aurora on timescales from milliseconds to minutes: A case study at subauroral latitudes

    SciTech Connect

    Ozaki, Mitsunori; Yagitani, Satoshi; Sawai, Kaoru; Shiokawa, Kazuo; Miyoshi, Yoshizumi; Kataoka, Ryuho; Ieda, Akimasa; Ebihara, Yusuke; Connors, Martin; Schofield, Ian; Katoh, Yuto; Otsuka, Yuichi; Sunagawa, Naoki; Jordanova, Vania K.

    2015-11-27

    A correlation was observed between chorus emissions and pulsating aurora (PA) from observations at Athabasca (L ≈ 4.3) in Canada at 9:00–9:20 UT on 7 February 2013, using an electron multiplying charge-coupled device camera and a VLF loop antenna with sampling rates of 110 Hz and 100 kHz, respectively. Pulsating aurora having a quasiperiodic variation in luminosity and a few hertz modulation was observed together with chorus emissions consisting of a group of successive rising-tone elements. The repetition period and modulation frequency of the PA are in good agreement with those of the modulated chorus. After 9:11 UT, the temporal features of the aurora became aperiodic PA of indistinct modulation. Simultaneously, the rising-tone chorus turned into chorus emissions consisting of numerous rising-tone elements. The equatorial geomagnetic field inhomogeneity calculated using the Tsyganenko 2002 model shows a decreasing trend during the period. This result is consistent with nonlinear wave growth theory having a small geomagnetic field inhomogeneity, which contributes to a decrease in the threshold amplitude to trigger discrete chorus elements. As a result, these observations show a close connection between chorus emissions and PA on timescales from milliseconds for generation of discrete chorus elements on the microphysics of wave-particle interaction to minutes for the variations of the geomagnetic field inhomogeneity related with the substorm activity.

  11. Van Allen Probes observations of prompt MeV radiation belt electron acceleration in nonlinear interactions with VLF chorus

    NASA Astrophysics Data System (ADS)

    Foster, J. C.; Erickson, P. J.; Omura, Y.; Baker, D. N.; Kletzing, C. A.; Claudepierre, S. G.

    2017-01-01

    Prompt recovery of MeV (millions of electron Volts) electron populations in the poststorm core of the outer terrestrial radiation belt involves local acceleration of a seed population of energetic electrons in interactions with VLF chorus waves. Electron interactions during the generation of VLF rising tones are strongly nonlinear, such that a fraction of the relativistic electrons at resonant energies are trapped by waves, leading to significant nonadiabatic energy exchange. Through detailed examination of VLF chorus and electron fluxes observed by Van Allen Probes, we investigate the efficiency of nonlinear processes for acceleration of electrons to MeV energies. We find through subpacket analysis of chorus waveforms that electrons with initial energy of hundreds of keV to 3 MeV can be accelerated by 50 keV-200 keV in resonant interactions with a single VLF rising tone on a time scale of 10-100 ms.

  12. Pseudacris triseriata (western chorus frog) and Rana sylvatica (wood frog) chytridiomycosis

    USGS Publications Warehouse

    Rittman, S.E.; Muths, E.; Green, D.E.

    2003-01-01

    The chytrid fungus Batrachochytrium dendrobatidis is a known pathogen of anuran amphibians, and has been correlated with amphibian die-offs worldwide (Daszak et. al. 1999. Emerging Infectious Diseases 5:735-748). In Colorado, B. dendrobatidis has infected Boreal toads (Bufo boreas) (Muths et. al., in review) and has been identified on museum specimens of northern leopard frogs (Rana pipiens) (Carey et. al. 1999. Develop. Comp. Immunol. 23:459-472). We report the first verified case of chytrid fungus in chorus frogs (Pseudacris triseriata) and wood frogs (Rana sylvatica) in the United States. We collected seven P. triseriata, and two adult and two juvenile R. sylvatica in the Kawuneeche Valley in Rocky Mountain National Park (RMNP) during June 2001. These animals were submitted to the National Wildlife Health Center (NWHC) as part of an amphibian health evaluation in RMNP. Chorus frogs were shipped in one container. Wood frog adults and juveniles were shipped in two separate containers. Histological examinations of all chorus frogs and 3 of 4 wood frogs were positive for chytrid fungus infection. The fourth (adult) wood frog was too decomposed for meaningful histology. Histological findings consisted of multifocally mild to diffusely severe infections of the epidermis of the ventrum and hindlimb digital skin. Chytrid thalli were confined to the thickened epidermis (hyperkeratosis), were spherical to oval, and occasional thalli contained characteristic discharge pores or zoospores (Green and Kagarise Sherman 1999. J. Herpetol 35:92-103; Fellers et al. 2001. Copeia 2001:945-953). We cannot confirm that all specimens carried the fungus at collection, because infection may have spread from one individual to all other individuals in each container during transport. Further sampling of amphibians in Kawuneeche Valley is warranted to determine the rate of infection and mortality in these populations.

  13. Equatorial electron loss by double resonance with oblique and parallel intense chorus waves

    NASA Astrophysics Data System (ADS)

    Mourenas, D.; Artemyev, A. V.; Agapitov, O. V.; Mozer, F. S.; Krasnoselskikh, V. V.

    2016-05-01

    Puzzling satellite observations of butterfly pitch angle distributions and rapid dropouts of 30-150 keV electrons are widespread in the Earth's radiation belts. Several mechanisms have been proposed to explain these observations, such as enhanced outward radial diffusion combined with magnetopause shadowing or scattering by intense magnetosonic waves, but their effectiveness is mainly limited to storm times. Moreover, the scattering of 30-150 keV electrons via cyclotron resonance with intense parallel chorus waves should be limited to particles with equatorial pitch angle smaller than 70°-75°, leaving unaffected a large portion of the population. In this paper, we investigate the possible effects of oblique whistler mode waves, noting, in particular, that Landau resonance with very oblique waves can occur up to ˜89°. We demonstrate that such very oblique chorus waves with realistic amplitudes can very efficiently nonlinearly transport nearly equatorially mirroring electrons toward smaller pitch angles where nonlinear scattering (phase bunching) via cyclotron resonance with quasi-parallel waves can take over and quickly send them to much lower pitch angles <40°. The proposed double resonance mechanism could therefore explain the formation of butterfly pitch angle distributions as well as contribute to some fast dropouts of 30-150 keV electrons occurring during moderate geomagnetic disturbances at L = 4-6. Since 30-150 keV electrons represent a seed population for a further acceleration to relativistic energies by intense parallel chorus waves during storms or substorms, the proposed mechanism may have important consequences on the dynamics of 100 keV to MeV electron fluxes in the radiation belts.

  14. Organic pollutant burden of the giant mussels Choromytilus chorus from the south-central Chilean coast.

    PubMed

    Toro, Beatriz; Palma-Fleming, Hernán; Navarro, Jorge M

    2004-04-01

    A comparative quantitative analysis was made on the contents of organochlorines (OCh) and polycyclic aromatic hydrocarbons (PAH) in tissues of the giant mussel Choromytilus chorus from three bays in south-central Chile exposed to various degrees of pollutant input. Mussels from the three bays contained levels of OCh near the detection limits of method, with a tendency to be slightly higher in the polluted bay (San Vicente) than in the other bays (Corral and Yaldad). PAH levels and types in Corral and Yaldad were well below of carcinogenicity permitted in mussels for human consumption.

  15. Recent Charm Production and Neutrino Oscillation Results From the CHORUS Experiment

    SciTech Connect

    Kayis-Topaksu, A.

    2006-07-11

    CHORUS Experiment was taking data during the years of 1994-1997. In total about 100 000 charged-current(CC) neutrino interactions were located in the nuclear emulsion target and fully reconstructed. In addition to the oscillation search, measurements of charm production have been also performed. From the sample of 100 000 events based on the data acquired by new automatic scanning system, 2013 charm-decay events were selected by a pattern recognition program. A comprehensive study of charm production by neutrinos being made. We report here some of the recent results on charm production and neutrino oscillation results.

  16. Excitation of whistler-mode chorus waves in a laboratory plasma

    NASA Astrophysics Data System (ADS)

    An, X.; Van Compernolle, B.; Bortnik, J.; Decyk, V.; Thorne, R. M.

    2016-12-01

    Whistler-mode chorus waves play an important role in the highly dynamic variability of the Earth's outer radiation belt. Here both broadband and discrete chirping whistler-mode emissions are excited in the laboratory by injecting a gyrating electron beam into a cold background plasma. The mode structure of these emissions is identified using an phase-correlation technique. The emission forms of the whistler waves strongly depend on plasma density, beam density and magnetic field profiles. Particle-in-cell simulations for the experiment shows an initial relaxation of the electron beam by Langmuir waves and subsequently growing whistler waves through both cyclotron resonance and Landau resonance.

  17. The statistical study of Chorus waves using the Double star TC1 data

    NASA Astrophysics Data System (ADS)

    Yearby, K.; Aryan, H.; Balikhin, M. A.; Krasnoselskikh, V.; Agapitov, O. V.

    2013-12-01

    The Double star satellite was launched on 29 December 2003 into an equatorial elliptical orbit with a perigee of 570km and an apogee of 78970km and an inclination of 28.5°. The satellite operated until 14 October 2007. The Double star TC1 data provides extensive coverage of the inner magnetosphere regions in the range of L shells >1.1L*, and a wide range of latitudes. This study presents a detailed statistical study of the Chorus waves during 4 years of the Double star operation.

  18. Bone fluoride concentrations of eastern grey kangaroos (Macropus giganteus) resident near an aluminium smelter in south-eastern Australia.

    PubMed

    Hufschmid, J; Beveridge, I; Coulson, G; Gould, J

    2011-08-01

    Lesions of skeletal and dental fluorosis have been described recently in eastern grey kangaroos (Macropus giganteus). The present study further examined the epidemiology of skeletal fluorosis in this species. Bone fluoride concentrations were obtained from a range of skeletal sites of animals from a high (Portland Aluminium) and a low (Cape Bridgewater) fluoride environment in Victoria, Australia. Age, but not sex, affected the mean bone fluoride concentration of kangaroos. For a given age, bone fluoride concentrations were significantly higher in kangaroos from Portland than Cape Bridgewater. Concentrations varied between skeletal sites examined, with samples containing cancellous bone having higher fluoride concentrations than those containing only cortical bone.

  19. Optimization and partial characterization of intracellular anticandidal protein from Aspergillus giganteus MTCC 8408 using taguchi DOE.

    PubMed

    Dutta, Debashis; Das, Mira Debnath

    2017-01-19

    A new intracellular antifungal protein (afp) production with average molecular weight 24.3 kDa and yield of 0.65 ± 0.1 mg/gram dry cell weight (gdcw) of mycelia in submerged fermentation of Aspergillus giganteus MTCC 8408 was optimized. Taguchi's DOE (design of experiment) L27 orthogonal array (OA) was constructed using Qualitek-4 software with 8 most influensive factors namely, culture pH, temperature, slant age, inoculum volume, agitation and KH2PO4. Scanning electron microscopy (SEM) was used to correlate the effect of selected factors on fungal cell morphology and afp production. The crude protein purification was accomplished using pure ammonium sulfate fractionation followed by carboxymethyl cellulose (CMC) ion-exchange chromatography and sephadex G-100 gel filtration. The average molecular mass of the purified protein was figured by silver stained SDS (sodium dodecylsulphate)-PAGE (poly-acryl amide gel electrophoresis). In vitro antifungal susceptibility assay was profiled against Candida albicans NCIM 3471 and minimum inhibitory concentrations (MICs) were in the range 3 to 4 µg/ml. Characterization of protein was observed with FTIR (Fourier transform infrared spectroscopy) analysis. The optimal production condition for crude afp was obtained as follows: soluble starch: 20 g/l; Corn steep liquor (CSL, 2%) + proteose peptone (PP, 1%): 30 g/l; pH: 5.8; temperature: 25°C; slant age: 3 d; inoculum size: 5% (v/v); agitation: 180 rpm; KH2PO4: 0.1 g/l. The validation experiments using optimized conditions confirmed an improvement in afp production by 59.4% against the expected enhancement of afp production by 61.22%. The present statistical optimization study revealed an opportunity to promote economical design at the industrial level for future scale up of effective antifungal agent against opportunistic oral and vaginal infection.

  20. Characterization of Miscanthus giganteus lignin isolated by ethanol organosolv process under reflux condition.

    PubMed

    Bauer, Stefan; Sorek, Hagit; Mitchell, Valerie D; Ibáñez, Ana B; Wemmer, David E

    2012-08-22

    Miscanthus giganteus lignin was extracted by an organosolv process under reflux conditions (4 h) with varying concentrations of ethanol (65%, 75%, 85%, 95%) and 0.2 M hydrochloric acid as catalyst. The resulting lignin was extensively characterized by size exclusion chromatography (SEC), Fourier-transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR), and chemical analysis (residual sugars, Klason lignin, ash). The predominant linkage units present were β-O-4' (82-84%), resinol (6-7%), and phenylcoumaran (10-11%). The 65% ethanol solvent system gave the lowest lignin yield (14% of starting biomass) compared to 29-32% of the other systems. Increasing ethanol concentration resulted in decreasing carbohydrate content of the lignins (3.6-1.1%), a higher solubility in tetrahydrofuran (THF), a slight reduction of the molecular weight (M(w) 2.72-2.25 KDa), an increasing α-ethoxylation, and an increase in ethoxylated phenylpropenoic compounds (p-coumaric and ferulic acid), but the S/G ratio of the monolignols (0.63, GC/MS) and Klason lignin content (86-88%) were unaffected. An extraction method for these ethyl-esterified phenylpropenoids and smaller molecular weight lignin compounds was developed. The effect of reaction time (2, 4, and 8 h) was investigated for the 95% ethanol solvent system. Besides increased lignin yield (13-43%), a slight increase in M(w) (2.21-2.38 kDa) and S/G ratio (0.53-0.68, GC-MS) was observed. Consecutive extractions suggested that these changes were not from lignin modifications (e.g., condensations) but rather from extraction of lignin of different composition. The results were compared to similar solvent systems with 95% acetone and 95% dioxane.

  1. Relationship between bioenergetics responses and organic pollutants in the giant mussel, Choromytilus chorus (Mollusca: Mytilidae).

    PubMed

    Toro, Beatriz; Navarro, Jorge M; Palma-Fleming, Hernán

    2003-05-08

    Samples of Choromytilus chorus (giant mussel) were collected at three sampling stations exposed to different degrees of pollution along the south-central portion of the Chilean coast in spring 1998 and summer 1999. Measurements were carried out on clearance rate, absorption efficiency, and oxygen consumption of the mussels under controlled laboratory conditions, and related to analytical data on organic pollutants in their tissues. Scope for growth (SFG) was employed as a physiological index to evaluate stress produced by pollutants existing at each sampling site. Individuals from San Vicente bay (highly polluted) showed negative SFG values in spring (-4.6 J/h per g) and summer (-3.5 J/h per g). These results indicated severe stress related to the accumulation of toxic compounds in their tissues. Specimens from Corral bay (medium level of pollution) gave a SFG of 15.5 J/h per g in spring and 6.5 J/h per g in summer, while those from Yaldad bay (low pollution) presented an inverse situation was observed with SFG values of 6.2 J/h per g in spring which was lower than the summer value of 25.7 J/h per g. There was a significant negative correlation between the SFG of the different populations of C. chorus and the concentrations of organochlorines (OChs) and polynuclear aromatic hydrocarbons (PAHs) in their tissues.

  2. Modulation of whistler-mode chorus waves by ULF and the effects on auroral precipitation

    NASA Astrophysics Data System (ADS)

    Jaynes, A. N.; Usanova, M.; Lessard, M.; Takahashi, K.; Ali, A.; Malaspina, D.; Michell, R.; Spanswick, E.; Donovan, E.; Klitzing, C.; Samara, M.; Spence, H. E.; Wygant, J. R.

    2016-12-01

    In this study, we present simultaneous observations of structured chorus waves being modulated by ULF waves generated as a result of a substorm injection. The in-situ wave data, measured by Van Allen Probes, were observed simultaneously with ground-based observations of pulsating aurora. Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch-angle scattering of 10's keV electrons in the equatorial magnetosphere. Recent satellite studies have strengthened this argument. In this case study, we propose the scenario being one of substorm-driven ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. To investigate the modulation of VLF waves further, we use the WHAMP plasma wave dispersion code to simulate this feature through ULF-modulated density variations. The emerging picture shows that ULF and VLF waves can be intimately related, which has implications for wave-particle interactions throughout the inner magnetosphere.

  3. Book review: A chorus of cranes: The cranes of North America and the world

    USGS Publications Warehouse

    Pearse, Aaron T.

    2017-01-01

    Cranes (Gruidae) are widely distributed throughout the world, have lived on Earth for several million years, and currently reside on five continents. Archaeological evidence and historical references suggest that humans have interacted with and been captivated by cranes for many thousands of years (e.g., Leslie 1988, Muellner 1990). A glimpse of our reverence for these birds can be found in A Chorus of Cranes by Paul A. Johnsgard, with photographs by Thomas D. Mangelsen. Many species of cranes are currently identified as threatened or endangered, and their future will likely rest in the hands of humans; this book presents their plight and some of the measures that have been taken to conserve them. Dr. Johnsgard, an emeritus professor at the University of Nebraska-Lincoln, is a prolific writer, having written more than 60 books in ornithology and other topics. This book serves as the latest update of previous efforts concerning crane biology, conservation, and management. A review without making comparisons to his past works is difficult, yet this assessment will primarily focus on the content of the current book, with little reference to past endeavors.A Chorus of Cranes: The Cranes of North America and the World by Paul A. Johnsgard. 2015. University Press of Colorado, Boulder, CO, USA. x + 208 pp., 38 color photographs, 41 figures. ISBN 978-1-60732-436-2. $23.95 (Ebook). ISBN 978-1-60732-436-9.

  4. Blind location and separation of callers in a natural chorus using a microphone array

    PubMed Central

    Jones, Douglas L.; Ratnam, Rama

    2009-01-01

    Male frogs and toads call in dense choruses to attract females. Determining the vocal interactions and spatial distribution of the callers is important for understanding acoustic communication in such assemblies. It has so far proved difficult to simultaneously locate and recover the vocalizations of individual callers. Here a microphone-array technique is developed for blindly locating callers using arrival-time delays at the microphones, estimating their steering-vectors, and recovering the calls with a frequency-domain adaptive beamformer. The technique exploits the time-frequency sparseness of the signal space to recover sources even when there are more sources than sensors. The method is tested with data collected from a natural chorus of Gulf Coast toads (Bufo valliceps) and Northern cricket frogs (Acris crepitans). A spatial map of locations accurate to within a few centimeters is constructed, and the individual call waveforms are recovered for nine individual animals within a 9×9 m2. These methods work well in low reverberation when there are no reflectors other than the ground. They will require modifications to incorporate multi-path propagation, particularly for the estimation of time-delays. PMID:19640054

  5. Habitat associations of chorusing anurans in the Lower Mississippi River Alluvial valley

    USGS Publications Warehouse

    Lichtenberg, J.S.; King, S.L.; Grace, J.B.; Walls, S.C.

    2006-01-01

    Amphibian populations have declined worldwide. To pursue conservation efforts adequately, land managers need more information concerning amphibian habitat requirements. To address this need, we examined relationships between anurans and habitat characteristics of wetlands in the Lower Mississippi River Alluvial Valley (LMAV). We surveyed chorusing anurans in 31 wetlands in 2000 and 28 wetlands in 2001, and measured microhabitat variables along the shoreline within the week following each survey. We recorded 12 species of anurans during our study. Species richness was significantly lower in 2000 than 2001 (t-test, P < 0.001) and correlated with an ongoing drought. We found species richness to be significantly greater at lake sites compared to impoundment, swale, and riverine sites (ANOVA, P = 0.002). We used stepwise regression to investigate the wetland types and microhabitat characteristics associated with species richness of chorusing anurans. Microhabitat characteristics associated with species richness included dense herbaceous vegetation and accumulated litter along the shoreline. Individual species showed species-specific habitat associations. The bronze frog, American bullfrog, and northern cricket frog were positively associated with lake sites (Fisher's Exact Test, P < 0.05), however wetland type did not significantly influence any additional species. Using bivariate correlations, we found that six of the seven most common species had significant associations with microhabitat variables. Overall, our findings support the view that conservation and enhancement of amphibian communities in the LMAV and elsewhere requires a matrix of diverse wetland types and habitat conditions. ?? 2006, The Society of Wetland Scientists.

  6. Spatio-Temporal Dynamics in Collective Frog Choruses Examined by Mathematical Modeling and Field Observations

    PubMed Central

    Aihara, Ikkyu; Mizumoto, Takeshi; Otsuka, Takuma; Awano, Hiromitsu; Nagira, Kohei; Okuno, Hiroshi G.; Aihara, Kazuyuki

    2014-01-01

    This paper reports theoretical and experimental studies on spatio-temporal dynamics in the choruses of male Japanese tree frogs. First, we theoretically model their calling times and positions as a system of coupled mobile oscillators. Numerical simulation of the model as well as calculation of the order parameters show that the spatio-temporal dynamics exhibits bistability between two-cluster antisynchronization and wavy antisynchronization, by assuming that the frogs are attracted to the edge of a simple circular breeding site. Second, we change the shape of the breeding site from the circle to rectangles including a straight line, and evaluate the stability of two-cluster and wavy antisynchronization. Numerical simulation shows that two-cluster antisynchronization is more frequently observed than wavy antisynchronization. Finally, we recorded frog choruses at an actual paddy field using our sound-imaging method. Analysis of the video demonstrated a consistent result with the aforementioned simulation: namely, two-cluster antisynchronization was more frequently realized. PMID:24463569

  7. Wave-Particle Interactions involving Whistler/Chorus Waves in the Earth's Radiation Belt

    NASA Astrophysics Data System (ADS)

    Echterling, N.; Schriver, D.; Roeder, J. L.; Fennell, J. F.

    2016-12-01

    Whistler mode chorus and electron cyclotron harmonic (ECH) waves are common in the Earth's radiation belt and have been detected by the Van Allen Probes at L 4-6 during the recovery of substorm plasma injections. During an event on January 13, 2013, quasi-periodic bursts of 16-40 keV electrons in very narrow, oblique ranges of pitch angles (75-80° and 100-105°) were observed by MagEIS, which were correlated with simultaneous bursts of upper-band, whistler-mode chorus waves. ECH emissions were also detected, but exhibited little correlation with the electron bursts. To understand the generation of these different wave emissions a linear theory and particle in cell (PIC) simulation study is being carried out using the observed velocity distribution functions as the starting point. Anisotropies and gradients in the distributions can lead to the generation of both whistler and ECH waves and the PIC simulations will be used to understand how these waves interact with the electrons non-linearly, which can lead to energy diffusion and pitch angle scattering. Comparisons between the simulation results and the Van Allen probe data will be made to determine acceleration, heating and transport of electrons in the radiation belt region due to wave-particle interactions.

  8. Sound level discrimination by gray treefrogs in the presence and absence of chorus-shaped noise

    PubMed Central

    Bee, Mark A.; Vélez, Alejandro; Forester, James D.

    2012-01-01

    An important aspect of hearing and acoustic communication is the ability to discriminate differences in sound level. Little is known about level discrimination in anuran amphibians (frogs and toads), for which vocal communication in noisy social environments is often critical for reproduction. This study used two-choice phonotaxis tests to investigate the ability of females of Cope’s gray treefrog (Hyla chrysoscelis) to discriminate between two advertisement calls differing only in sound pressure level by 2, 4, or 6 dB. Tests were conducted in the presence and absence of chorus-shaped noise (73 dB) and using two different ranges of signal levels (73–79 dB and 79–85 dB). Females discriminated between two signals differing by as little as 2–4 dB. In contrast to expectations based on the “near miss to Weber’s law” in birds and mammals, level discrimination was slightly better at the lower range of signal amplitudes, a finding consistent with earlier studies of frogs and insects. Realistic levels of background noise simulating a breeding chorus had no discernable effect on discrimination at the sound level differences tested in this study. These results have important implications for studies of auditory masking and signaling behavior in the contexts of anuran hearing and sound communication. PMID:22559390

  9. Unraveling the excitation mechanisms of highly oblique lower-band chorus waves

    SciTech Connect

    Li, Wen; Mourenas, D.; Artemyev, A. V.; Bortnik, J.; Thorne, R. M.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Reeves, Geoffrey D.; Funsten, Herbert O.; Spence, H. E.

    2016-08-17

    Excitation mechanisms of highly oblique, quasi-electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth's magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first time. The first mechanism relies on cyclotron resonance with electrons possessing both a realistic temperature anisotropy at keV energies and a plateau at 100–500 eV in the parallel velocity distribution. The second mechanism corresponds to Landau resonance with a 100–500 eV beam. In both cases, a small low-energy beam-like component is necessary for suppressing an otherwise dominating Landau damping. In conclusion, our new findings suggest that small variations in the electron distribution could have important impacts on energetic electron dynamics.

  10. Sound level discrimination by gray treefrogs in the presence and absence of chorus-shaped noise.

    PubMed

    Bee, Mark A; Vélez, Alejandro; Forester, James D

    2012-05-01

    An important aspect of hearing and acoustic communication is the ability to discriminate differences in sound level. Little is known about level discrimination in anuran amphibians (frogs and toads), for which vocal communication in noisy social environments is often critical for reproduction. This study used two-choice phonotaxis tests to investigate the ability of females of Cope's gray treefrog (Hyla chrysoscelis) to discriminate between two advertisement calls differing only in sound pressure level by 2, 4, or 6 dB. Tests were conducted in the presence and absence of chorus-shaped noise (73 dB) and using two different ranges of signal levels (73-79 dB and 79-85 dB). Females discriminated between two signals differing by as little as 2-4 dB. In contrast to expectations based on the "near miss to Weber's law" in birds and mammals, level discrimination was slightly better at the lower range of signal amplitudes, a finding consistent with earlier studies of frogs and insects. Realistic levels of background noise simulating a breeding chorus had no discernable effect on discrimination at the sound level differences tested in this study. These results have important implications for studies of auditory masking and signaling behavior in the contexts of anuran hearing and sound communication.

  11. Unraveling the excitation mechanisms of highly oblique lower-band chorus waves

    DOE PAGES

    Li, Wen; Mourenas, D.; Artemyev, A. V.; ...

    2016-08-17

    Excitation mechanisms of highly oblique, quasi-electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth's magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first time. The first mechanism relies on cyclotron resonance with electrons possessing both a realistic temperature anisotropy at keV energies and a plateau at 100–500 eV in the parallel velocity distribution.more » The second mechanism corresponds to Landau resonance with a 100–500 eV beam. In both cases, a small low-energy beam-like component is necessary for suppressing an otherwise dominating Landau damping. In conclusion, our new findings suggest that small variations in the electron distribution could have important impacts on energetic electron dynamics.« less

  12. Unraveling the excitation mechanisms of highly oblique lower-band chorus waves

    SciTech Connect

    Li, Wen; Mourenas, D.; Artemyev, A. V.; Bortnik, J.; Thorne, R. M.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Reeves, Geoffrey D.; Funsten, Herbert O.; Spence, H. E.

    2016-08-17

    Excitation mechanisms of highly oblique, quasi-electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth's magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first time. The first mechanism relies on cyclotron resonance with electrons possessing both a realistic temperature anisotropy at keV energies and a plateau at 100–500 eV in the parallel velocity distribution. The second mechanism corresponds to Landau resonance with a 100–500 eV beam. In both cases, a small low-energy beam-like component is necessary for suppressing an otherwise dominating Landau damping. In conclusion, our new findings suggest that small variations in the electron distribution could have important impacts on energetic electron dynamics.

  13. White-throated sparrows alter songs differentially in response to chorusing anurans and other background noise.

    PubMed

    Lenske, Ariel K; La, Van T

    2014-06-01

    Animals can use acoustic signals to attract mates and defend territories. As a consequence, background noise that interferes with signal transmission has the potential to reduce fitness, especially in birds that rely on song. While much research on bird song has investigated vocal flexibility in response to urban noise, weather and other birds, the possibility of inter-class acoustic competition from anurans has not been previously studied. Using sound recordings from central Ontario wetlands, we tested if white-throated sparrows (Zonotrichia albicolis) make short-term changes to their singing behaviour in response to chorusing spring peepers (Pseudacris crucifer), as well as to car noise, wind and other bird vocalizations. White-throated sparrow songs that were sung during the spring peeper chorus were shorter with higher minimum frequencies and narrower bandwidths resulting in reduced frequency overlap. Additionally, sparrows were less likely to sing when car noise and the vocalizations of other birds were present. These patterns suggest that birds use multiple adjustment strategies. This is the first report to demonstrate that birds may alter their songs differentially in response to different sources of noise. This article is part of a Special Issue entitled: insert SI title.

  14. Simulation of radiation belt electron dynamics using in-situ global model of chorus waves inferred from the low-altitude electron precipitation

    NASA Astrophysics Data System (ADS)

    Li, W.; Thorne, R. M.; Ni, B.; Bortnik, J.; Ma, Q.; Chen, L.; Kletzing, C.; Kurth, W. S.; Hospodarsky, G. B.; Green, J. C.; Baker, D. N.; Kanekal, S. G.; Reeves, G. D.; Henderson, M. G.; Spence, H.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.

    2013-12-01

    The global evolution of chorus wave intensity is crucial to evaluate the electron local acceleration by chorus waves, which is fundamentally important for radiation belt electron dynamics. Based on the fact that chorus waves play a dominant role in scattering 30-100 keV electrons, we adopt a physics-based technique of inferring chorus wave amplitudes from the low-altitude electron population (30-100 keV) measured by multiple POES/MetOp satellites, which provide extensive coverage over a broad L-MLT region. This technique is validated through analyzing conjunction events with the Van Allen Probes measuring chorus wave amplitudes near the equator and POES/MetOp satellites measuring the 30-100 keV electron population at the conjugate low altitudes. We adopt this technique to construct chorus wave intensity distributions, which are then used to simulate the radiation belt electron dynamics during the 09 October 2012 storm. The simulation results show that the pronounced electron acceleration to relativistic energies with a peak in phase space density observed by the Van Allen probes was primarily caused by chorus-driven local acceleration. Our numerical simulation of local stochastic acceleration not only accounts for the timescale and energy dependence of the rapid increase in electron flux in the heart of the outer radiation belt, but also reproduces the evolution of the observed electron pitch angle distribution.

  15. Observation of a unique storm-time VLF chorus emissions at low latitude Indian ground station Jammu (L=1.17)

    NASA Astrophysics Data System (ADS)

    Singh, K. K.

    2017-08-01

    This paper summarizes a unique observation of storm-time VLF chorus emissions obtained during investigation of VLF data collected over a period of about one year at our low latitude ground-based Indian station Jammu (geomag. lat., 22 deg 26 min North, L=1.17) in order to connect the peculiarities of this ground-observed VLF chorus with the plasma processes in the magnetosphere during geomagnetic disturbances. The upper boundary frequency method (UBF-method) based on the measurement of the upper boundary frequency of the ground-observed chorus is used for the determination of the location of the source of storm-time chorus emissions observed at our ground station Jammu. Dynamics of chorus spectra of the emissions observed at Jammu on 18 February 1998 in daytime during magnetic storm period are investigated in detail in order to solve the physics of the ground-observed chorus emissions at low latitudes. To explain various temporal and spectral features of storm-time VLF chorus emissions observed at Jammu, a generation mechanism based on the backward wave oscillator (BWO) regime of the magnetospheric cyclotron maser has been presented. Using BWO model, the calculation of some magnetospheric parameters such as plasma density, large-scale electric field etc. are carried out. The conformity between the calculated and typical measured parameters is shown and discussed. Finally the conclusion of this study is reported.

  16. Spacecraft Observations of Quasi-Electrostatic Chorus Waves: Effective Length of a Receiving Antenna

    NASA Astrophysics Data System (ADS)

    Shirokov, Evgenii; Demekhov, Andrei; Chugunov, Yury; Larchenko, Alexey

    2017-04-01

    Whistler-mode chorus is a typical example of very low frequency electromagnetic emission in the Earth's and planetary magnetospheres. Chorus emissions typically propagate quasi-parallel to the ambient magnetic field in their source region but can also propagate in the quasi-electrostatic mode close to the lower oblique resonance cone. However, the quasi-electrostatic wave field measurements by electric receiving antennas in a magnetoplasma are nontrivial. Indeed, the incident wave electric field amplitude E should be obtained from voltage U = Eleff induced on the receiving antenna, where leff is the so-called antenna effective length. The value of leff can be greater and even much greater than the antenna geometric length lgeom in case of the short (as compared to the electromagnetic wavelength in a plasma) antennas. This is because such antennas effectively re-radiate quasi-electrostatic waves in plasmas. Length leff should be calculated considering the plasma and wave characteristics, and, in general, this is quite a difficult problem. In this work, we propose a method of calculating the effective length of a short receiving antenna for the case of spacecraft observations of quasi-electrostatic chorus emissions, and an analytical expression for this parameter is obtained. This method is based on the reciprocity theorem for quasi-electrostatic waves, which is also correct in gyrotropic and dispersive media such as magnetoplasmas, and requires an appropriate choice of the radiation source model. Such a choice is possible on the basis of the measured emission parameters if a quasi-monochromatic wave packet with wave normal angles near the resonance cone is detected. We calculate the receiver effective length for some measurements of chorus wave quasi-electrostatic fields onboard THEMIS spacecraft using the proposed method. The emission parameters such as the wave normal angle have been found using the singular value decomposition method applied to the magnetic field

  17. Intrastrain Comparison of the Chemical Composition and Antioxidant Activity of an Edible Mushroom, Pleurotus giganteus, and Its Potent Neuritogenic Properties

    PubMed Central

    David, Pamela; Tan, Yee-Shin; Wong, Kah-Hui; Kuppusamy, Umah Rani; Sabaratnam, Vikineswary

    2014-01-01

    Two strains of Pleurotus giganteus (commercial and wild) were tested for their ability to induce neurite outgrowth in rat pheochromocytoma (PC12) and mouse neuroblastoma-2a (N2a) cells. Treatment with the mushroom extracts resulted in neuronal differentiation and neuronal elongation, but not nerve growth factor (NGF) production. Linoleic acid (4.5–5.0%, w/w) which is a major fatty acid present in the ethanol extract promoted NGF biosynthesis when augmented with low concentration of NGF (5 ng/mL). The two strains of mushroom were found to be high in protein (154–192 g kg−1), total polysaccharides, phenolics, and flavonoids as well as vitamins B1, B2, and B3. The total phenolics present in the mushroom extracts were positively correlated to the antioxidant activity (free radical scavenging, ferric reducing power, and lipid peroxidation inhibition). To conclude, P. giganteus could potentially be used in well-balanced diet and as a source of dietary antioxidant to promote neuronal health. PMID:25121118

  18. Intrastrain comparison of the chemical composition and antioxidant activity of an edible mushroom, Pleurotus giganteus, and its potent neuritogenic properties.

    PubMed

    Phan, Chia-Wei; David, Pamela; Tan, Yee-Shin; Naidu, Murali; Wong, Kah-Hui; Kuppusamy, Umah Rani; Sabaratnam, Vikineswary

    2014-01-01

    Two strains of Pleurotus giganteus (commercial and wild) were tested for their ability to induce neurite outgrowth in rat pheochromocytoma (PC12) and mouse neuroblastoma-2a (N2a) cells. Treatment with the mushroom extracts resulted in neuronal differentiation and neuronal elongation, but not nerve growth factor (NGF) production. Linoleic acid (4.5-5.0%, w/w) which is a major fatty acid present in the ethanol extract promoted NGF biosynthesis when augmented with low concentration of NGF (5 ng/mL). The two strains of mushroom were found to be high in protein (154-192 g kg(-1)), total polysaccharides, phenolics, and flavonoids as well as vitamins B1, B2, and B3. The total phenolics present in the mushroom extracts were positively correlated to the antioxidant activity (free radical scavenging, ferric reducing power, and lipid peroxidation inhibition). To conclude, P. giganteus could potentially be used in well-balanced diet and as a source of dietary antioxidant to promote neuronal health.

  19. Arbuscular mycorrhizal fungal inoculation protects Miscanthus × giganteus against trace element toxicity in a highly metal-contaminated site.

    PubMed

    Firmin, Stéphane; Labidi, Sonia; Fontaine, Joël; Laruelle, Frédéric; Tisserant, Benoit; Nsanganwimana, Florian; Pourrut, Bertrand; Dalpé, Yolande; Grandmougin, Anne; Douay, Francis; Shirali, Pirouz; Verdin, Anthony; Lounès-Hadj Sahraoui, Anissa

    2015-09-15

    Arbuscular mycorrhizal fungus (AMF)-assisted phytoremediation could constitute an ecological and economic method in polluted soil rehabilitation programs. The aim of this work was to characterize the trace element (TE) phytoremediation potential of mycorrhizal Miscanthus × giganteus. To understand the mechanisms involved in arbuscular mycorrhizal symbiosis tolerance to TE toxicity, the fatty acid compositions and several stress oxidative biomarkers were compared in the roots and leaves of Miscanthus × giganteus cultivated under field conditions in either TE-contaminated or control soils. TEs were accumulated in greater amounts in roots, but the leaves were the organ most affected by TE contamination and were characterized by a strong decrease in fatty acid contents. TE-induced oxidative stress in leaves was confirmed by an increase in the lipid peroxidation biomarker malondialdehyde (MDA). TE contamination decreased the GSSG/GSH ratio in the leaves of exposed plants, while peroxidase (PO) and superoxide dismutase (SOD) activities were increased in leaves and in whole plants, respectively. AMF inoculation also increased root colonization in the presence of TE contamination. The mycorrhizal colonization determined a decrease in SOD activity in the whole plant and PO activities in leaves and induced a significant increase in the fatty acid content in leaves and a decrease in MDA formation in whole plants. These results suggested that mycorrhization is able to confer protection against oxidative stress induced by soil pollution. Our findings suggest that mycorrhizal inoculation could be used as a bioaugmentation technique, facilitating Miscanthus cultivation on highly TE-contaminated soil.

  20. The Effect of Speech Rate on Stuttering Frequency, Phonated Intervals, Speech Effort, and Speech Naturalness during Chorus Reading

    ERIC Educational Resources Information Center

    Davidow, Jason H.; Ingham, Roger J.

    2013-01-01

    Purpose: This study examined the effect of speech rate on phonated intervals (PIs), in order to test whether a reduction in the frequency of short PIs is an important part of the fluency-inducing mechanism of chorus reading. The influence of speech rate on stuttering frequency, speaker-judged speech effort, and listener-judged naturalness was also…

  1. The Effect of Speech Rate on Stuttering Frequency, Phonated Intervals, Speech Effort, and Speech Naturalness during Chorus Reading

    ERIC Educational Resources Information Center

    Davidow, Jason H.; Ingham, Roger J.

    2013-01-01

    Purpose: This study examined the effect of speech rate on phonated intervals (PIs), in order to test whether a reduction in the frequency of short PIs is an important part of the fluency-inducing mechanism of chorus reading. The influence of speech rate on stuttering frequency, speaker-judged speech effort, and listener-judged naturalness was also…

  2. Comparative Biogeochemical Cycles of Bioenergy Crops Reveal Nitrogen-Fixation and Low GHG Emissions in a Miscanthus x giganteus Agro-ecosystem

    USDA-ARS?s Scientific Manuscript database

    We evaluated the relative greenhouse gas mitigation potential of plant species considered as biofuel feedstock crops by simulating the biogeochemical processes associated with Miscanthus x giganteus, Panicum virgatum, Zea mays, and a mixed prairie community. DayCent model simulations for Miscanthus ...

  3. Cool C4 Photosynthesis - Pyruvate Pi dikinase expression and activity corresponds to the exceptional cold tolerance of carbon assimilation in Miscanthus x giganteus

    USDA-ARS?s Scientific Manuscript database

    The biofuel feedstock grass Miscanthus x giganteus is exceptional among C4 species in its high productivity in cold climates. It can maintain photosynthetically active leaves at temperatures 6°C below the minimum for Zea mays (maize), which allows it a longer growing season in cool climates. Underst...

  4. The Dusk Chorus from an Owl Perspective: Eagle Owls Vocalize When Their White Throat Badge Contrasts Most

    PubMed Central

    Penteriani, Vincenzo; Delgado, Maria del Mar

    2009-01-01

    Background An impressive number of studies have investigated bird vocal displays, and many of them have tried to explain the widespread phenomenon of the so-called dawn and dusk chorus, the sunrise and sunset peaks in bird song output. As many as twelve non-exclusive hypotheses have been proposed to explain why twilight peaks in vocal display might be advantageous; but, even after more than two decades of study, the basis underlying the dusk and dawn chorus is still unclear. Moreover, to date, the majority of studies on this topic have focused on songbirds. Methodology/Principal Findings We investigate here a novel hypothesis on why nocturnal birds with patches of white feathers call at twilight. We propose that white plumage patches and the timing of visual signaling have co-evolved to maximize the effectiveness of social communication such as the dusk chorus. This hypothesis centers on the recent discovery that eagle owls can adopt specific forms of visual signaling and is supported by the observation that adult eagle owls possess a white throat badge that is only visible during vocal displays. By monitoring the calling of eagle owls at dusk, a peak time for bird call output, we found that white throat badges contrasted most with the surrounding background during the owls' twilight chorusing. Conclusions/Significance Crepuscular and nocturnal species appear to have evolved white patches that, shown in association with vocal displays, allow them to communicate in dark surroundings. The evolution of a white badge that operates jointly with call displays at dawn and dusk may be relevant to the eagle owls' social dynamics. Our explanation for the dusk chorus may possibly represent an overlooked but common pattern of signaling among crepuscular and nocturnal birds that combine patches of white feathers with twilight displays. Furthermore, our findings could be relevant to songbirds that breed in dark forest habitats and have contrasting white badges, as well as birds

  5. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations

    SciTech Connect

    Fu, Xiangrong; Cowee, Misa M.; Friedel, Reinhard H.; Funsten, Herbert O.; Gary, S. Peter; Hospodarsky, George B.; Kletzing, Craig; Kurth, William; Larsen, Brian A.; Liu, Kaijun; MacDonald, Elizabeth A.; Reeves, Geoffrey D.; Skoug, Ruth M.; Winske, Dan

    2014-10-22

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ~Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

  6. Whistler anisotropy instabilities as the source of banded chorus: Van Allen Probes observations and particle-in-cell simulations

    DOE PAGES

    Fu, Xiangrong; Cowee, Misa M.; Friedel, Reinhard H.; ...

    2014-10-22

    Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from Helium, Oxygen, Proton, and Electron instrument measurements on the Van Allen Probes A satellite during a bandedmore » chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper band chorus and that the hot component drives the electromagnetic lower band chorus; the gap at ~Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.« less

  7. Seasonal reproduction and feeding ecology of giant isopods Bathynomus giganteus from the continental slope of the Yucatán peninsula

    NASA Astrophysics Data System (ADS)

    Barradas-Ortiz, Cecilia; Briones-Fourzán, Patricia; Lozano-Álvarez, Enrique

    2003-04-01

    The reproduction and feeding habits of giant isopods Bathynomus giganteus [range in body length (BL): 43-363 mm] from the continental slope of the Yucatán Peninsula, México, were studied from samples collected at depths of 359-1050 m during three research cruises conducted in winter, spring, and summer of different years. Samples taken in winter and spring yielded a large proportion of mancas and juveniles, as well as high percentages of adult females with functional oostegites and males with appendices masculinae, suggesting a peak in reproductive activity during these seasons. In contrast, the virtual absence in the summer samples of (a) mancas and small juveniles, (b) females with functional oostegites, and (c) small adult males (210-290 mm BL) with appendices masculinae, suggests a low reproductive activity of B. giganteus during summer. Stomach contents analyses were conducted on five life phases (mancas, small juveniles, large juveniles, adult females and adult males) in winter and summer. Mancas and juveniles had fuller stomachs than adults during winter, and all isopods had emptier stomachs during summer than during winter. The diet of B. giganteus was broad, but the most important food categories in all life phases were fish and squid remains, underlining the main scavenging habits of B. giganteus. However, the remaining food categories show that this species is a facultative rather than a strict scavenger and suggest some ontogenetic dietary shifts. These results were further supported by diet (Horn's) overlap indices. In the winter, high diet overlap occurred between all life phases. In the summer, adult males had a low diet overlap with adult females and large juveniles. Adult males also had a low diet overlap between summer and winter. Results from this and other studies suggest that the main reproductive activity of B. giganteus in the Yucatán slope occurs during winter and spring, when the food supply on the upper-slope is highest, particularly

  8. Water use and the thermoregulatory behaviour of kangaroos in arid regions: insights into the colonisation of arid rangelands in Australia by the Eastern Grey Kangaroo (Macropus giganteus).

    PubMed

    Dawson, Terence J; McTavish, Kirsten J; Munn, Adam J; Holloway, Joanne

    2006-01-01

    The Eastern Grey Kangaroo (Macropus giganteus) occurs mostly in the wetter regions of eastern Australia. However, in the past 30-40 years it has moved into more arid regions (rainfall < 250 mm), thus increasing its overlap zone with the xeric adapted Red Kangaroo (Macropus rufus). An increased access to water (supplied for domestic stock) may explain this range extension, but changes in the availability of preferred feed could also be involved. The water use, drinking patterns and thermoregulatory behaviour of these two species of kangaroo have been examined in a semi-free range study, during summer at an arid rangeland site. Foraging was largely nocturnal in both species and during the day they behaved to reduce heat loads. This was especially so for M. giganteus, which showed greater shade seeking. However, it still used more water (72 +/- 2.6 mL kg(-1) day(-1), mean +/- SE) than M. rufus (56 +/- 7.6 mL kg(-1) day(-1)) and drank twice as frequently. Although M. giganteus produced a less concentrated urine (1422 +/- 36 mosmol kg(-1)) than M. rufus (1843 +/- 28 mosmol kg(-1)), kidney physiology did not explain all of the differences in water metabolism between the species. Water from the feed and faecal water retention also appear to be involved. Broadly, a better access to reliable water and the utilisation of mesic microhabitats has enabled M. giganteus to make inroads into the changing rangelands of eastern Australia. However, changes in the vegetation, due to stock grazing, have also favoured M. giganteus, which is a grass eating specialist.

  9. Transcriptional responses indicate maintenance of photosynthetic proteins as key to the exceptional chilling tolerance of C4 photosynthesis in Miscanthus × giganteus

    PubMed Central

    Spence, Ashley K.; Boddu, Jay; Wang, Dafu; James, Brandon; Swaminathan, Kankshita; Moose, Stephen P.; Long, Stephen P.

    2014-01-01

    Miscanthus × giganteus is exceptional among C4 plants in its ability to acclimate to chilling (≤14 °C) and maintain a high photosynthetic capacity, in sharp contrast to maize, leading to very high productivity even in cool temperate climates. To identify the mechanisms that underlie this acclimation, RNA was isolated from M × giganteus leaves in chilling and nonchilling conditions and hybridized to microarrays developed for its close relative Zea mays. Among 21 000 array probes that yielded robust signals, 723 showed significant expression change under chilling. Approximately half of these were for annotated genes. Thirty genes associated with chloroplast membrane function were all upregulated. Increases in transcripts for the lhcb5 (chlorophyll a/b-binding protein CP26), ndhF (NADH dehydrogenase F, chloroplast), atpA (ATP synthase alpha subunit), psbA (D1), petA (cytochrome f), and lhcb4 (chlorophyll a/b-binding protein CP29), relative to housekeeping genes in M. × giganteus, were confirmed by quantitative reverse-transcription PCR. In contrast, psbo1, lhcb5, psbA, and lhcb4 were all significantly decreased in Z. mays after 14 days of chilling. Western blot analysis of the D1 protein and LHCII type II chlorophyll a/b-binding protein also showed significant increases in M. × giganteus during chilling and significant decreases in Z. mays. Compared to other C4 species, M. × giganteus grown in chilling conditions appears to counteract the loss of photosynthetic proteins and proteins protecting photosystem II typically observed in other species by increasing mRNA levels for their synthesis. PMID:24958895

  10. On the conditions for nonlinear growth in magnetospheric chorus and triggered emissions

    NASA Astrophysics Data System (ADS)

    Gołkowski, Mark; Gibby, Andrew R.

    2017-09-01

    The nonlinear whistler mode instability associated with magnetospheric chorus and VLF triggered emissions continues to be poorly understood. Following up on formulations of other authors, an analytical exploration of the stability of the phenomenon from a new vantage point is given. This exploration derives an additional requirement on the anisotropy of the energetic electron distribution relative to the linear treatment of the instability, and shows that the nonlinear instability is most favorable to increasing growth rate when electrons become initially trapped in the wave potential of a constant frequency wave. These results imply that the initiation of the nonlinear instability at the equator requires a positive frequency sweep rate, while the initiation of the instability by a constant frequency triggering wave must occur at a location downstream of the geomagnetic equator.

  11. Laboratory experiment on the excitation of whistler-mode chorus waves

    NASA Astrophysics Data System (ADS)

    An, Xin; van Compernolle, Bart; Bortnik, Jacob; Decyk, Viktor; Thorne, Richard

    2016-10-01

    Whistler-mode chorus waves play an important role in accelerating electrons to relativistic energies in the heart of the outer radiation belt, as well as in precipitating electrons to the atmosphere. An experiment in the Large Plasma Device at UCLA generates both broadband and discrete chirping whistler-mode emissions using a gyrating electron beam injected into a cold background plasma. The mode structure of these emissions is identified using a phase-correlation technique. The emission forms of the whistler waves depend on plasma density, beam density and magnetic field profiles. A kinetic simulation in accordance with the experiment shows an initial relaxation of the electron beam by Langmuir waves and subsequently growing whistler waves through cyclotron resonance and Landau resonance. The research was funded by the Department of Energy and the National Science Foundation by Grant DE-SC0010578 and was also funded by NASA Grant NNX16AG21G.

  12. Properties of electron flux spectra around the plasmapause in the chorus and hiss regions using POES.

    NASA Astrophysics Data System (ADS)

    Whittaker, Ian; Rodger, Craig; Clilverd, Mark

    2014-05-01

    The European FP7 PLASMON project aims to provide observations of plasmaspheric densities, and link the plasmaspheric variations to relativistic electron precipitation from the radiation belts. This is intended to assist in the estimation and prevent damage of space assets from space weather events as well as to improve forecasting (http://plasmon.elte.hu). As part of the PLASMON project, electron fluxes from the POES series of satellites are being used to determine the link between energetic electron precipitation energy spectra and magnitude to the position of the plasmapause. The MEPED instrument onboard POES measures electron flux from 90° (trapped particles) and 0° (losscone) telescopes, in 3 integral energy channels (>30, >100 and >300 keV). These fluxes have been compared to the DEMETER/IDP instrument to confirm that published geometric factor corrections (Yando et al. 2011) can be accurately applied to the POES data to produce as accurate as possible fluxes. These global fluxes have then been separated into regions in which Chorus (23:00-11:00 MLT) and Hiss (11:00-16:00 MLT) whistler mode waves are expected to occur, in 0.2 L-shell bins with a 20 minute temporal resolution. The plasmapause locations have been determined from the O'Brien and Moldwin (2003) models based on Kp, Ae and Dst peaks. We are currently comparing the POES spectral gradient and flux magnitude with plasmapause location and geomagnetic activity for the locations in which chorus and hiss are known to occur. This presentation will focus on the electron flux spectral gradient behaviour either side of the plasmapause, a value that is difficult to measure from ground based techniques.

  13. Statistical analysis of electron lifetimes at GEO: Comparisons with chorus-driven losses

    NASA Astrophysics Data System (ADS)

    Boynton, R. J.; Balikhin, M. A.; Mourenas, D.

    2014-08-01

    The population of electrons in the Earth's outer radiation belt increases when the magnetosphere is exposed to high-speed streams of solar wind, coronal mass ejections, magnetic clouds, or other disturbances. After this increase, the number of electrons decays back to approximately the initial population. This study statistically analyzes the lifetimes of the electron at Geostationary Earth Orbit (GEO) from Los Alamos National Laboratory electron flux data. The decay rate of the electron fluxes are calculated for 14 energies ranging from 24 keV to 3.5 MeV to identify a relationship between the lifetime and energy of the electrons. The statistical data show that electron lifetimes increase with energy. Also, the statistical results show a good agreement up to ˜1 MeV with an analytical model of lifetimes, where electron losses are caused by their resonant interaction with oblique chorus waves, using average wave intensities obtained from Cluster statistics. However, above 500 keV, the measured lifetimes increase with energy becomes less steep, almost stopping. This could partly stem from the difficultly of identifying lifetimes larger than 10 days, for high energy, with the methods and instruments of the present study at GEO. It could also result from the departure of the actual geomagnetic field from a dipolar shape, since a compressed field on the dayside should preferentially increase chorus-induced losses at high energies. However, during nearly quiet geomagnetic conditions corresponding to lifetime measurement periods, it is more probably an indication that outward radial diffusion imposes some kind of upper limit on lifetimes of high-energy electrons near geostationary orbit.

  14. Nonlinear pitch angle scattering of energetic electrons near the loss cone by whistler mode chorus emissions

    NASA Astrophysics Data System (ADS)

    Kitahara, M.; Katoh, Y.

    2016-12-01

    Chorus emissions are coherent whistler mode waves observed in the inner magnetosphere and scatter the pitch angle of energetic electrons, while the precipitation of energetic electrons into the atmosphere contributes to diffuse and pulsating aurora. Conventionally, it has been considered that particles that satisfy the cyclotron resonance condition in the energy range from a few keV to tens of keV are scattered toward the loss cone by whistler mode waves. While the nonlinear motion of resonant particles encountering a coherent wave has been studied more than 40 years (cf. Omura et al., 1991), in the derivation of the equations, previous studies assumed small wave amplitude compared to the ambient magnetic field B0 (Dysthe, 1971) and large pitch angle of energetic electrons (Nunn, 1974). In this study, we derive the equations without both of the assumptions, and theoretically evaluate the additional term related to the Lorentz force caused by the wave magnetic field and the parallel velocity of particles. Furthermore, we carry out a test particle simulation and reproduce that the additional term plays a role of the pitch angle scattering away from the loss cone. In the simulation results of parallel propagating coherent waves with constant frequency, diffusion-like scattering of resonant electrons is observed in the case of waves with weak amplitude (0.1 % of B0). On the contrary, all of resonant electrons are scattered in the pitch angle away from the loss cone in the case of waves with larger amplitude (more than 0.5 % of B0). We also carry out simulations for the case of waves with frequency sweeping and find that particles near the loss cone are more effectively scattered away from the loss cone by the wave with large amplitude (more than 0.7 % of B0). These results suggest that the relation between chorus wave intensity and the flux of auroral electron precipitation is not straightforward and should be investigated by considering the nonlinear effects.

  15. Correlated Pc4-5 ULF waves, whistler-mode chorus and pulsating aurora observed by the Van Allen Probes and ground-based systems

    NASA Astrophysics Data System (ADS)

    Jaynes, A. N.; Lessard, M.; Takahashi, K.; Ali, A.; Malaspina, D.; Michell, R.; Spanswick, E.; Baker, D. N.; Blake, J. B.; Cully, C. M.; Donovan, E.; Kletzing, C.; Reeves, G. D.; Samara, M.; Spence, H. E.; Wygant, J. R.

    2015-12-01

    Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch-angle scattering of 10's keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and 10's keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4-5 compressional pulsations and modulation of whistler-mode chorus using THEMIS. In the current study, we present simultaneous in-situ observations of structured chorus waves and an apparent field line resonance (in the Pc4-5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4-5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with the same modulation in a nearby pulsating aurora patch. Such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades, and may be a result of nonlinear chorus wave interactions in the equatorial region. This work illustrates the significant understanding of magnetospheric processes that can be gained through use of conjunctive ground- and space-based observations.

  16. Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

    SciTech Connect

    Jaynes, A. N.; Lessard, M. R.; Takahashi, K.; Ali, A. F.; Malaspina, D. M.; Michell, R. G.; Spanswick, E. L.; Baker, D. N.; Blake, J. B.; Cully, C.; Donovan, E. F.; Kletzing, C. A.; Reeves, G. D.; Samara, M.; Spence, H. E.; Wygant, J. R.

    2015-10-28

    Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch angle scattering of tens of keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and tens of keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4–5 compressional pulsations and modulation of whistler-mode chorus using Time History of Events and Macroscale Interactions during Substorms. In the current study, we present simultaneous in situ observations of structured chorus waves and an apparent field line resonance (in the Pc4–5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4–5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with the same modulation in a nearby pulsating aurora patch. As a result, such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades and may be a result of nonlinear chorus wave interactions in the equatorial region.

  17. Developing County-level Water Footprints of Biofuel Produced from Switchgrass and Miscanthus x Giganteus in the United States

    SciTech Connect

    Wu, May M.; Chiu, Yi-Wen

    2014-09-30

    Perennial grass has been proposed as a potential candidate for producing cellulosic biofuel because of its promising productivity and benefits to water quality, and because it is a non-food feedstock. While extensive research focuses on selecting and developing species and conversion technologies, the impact of grass-based biofuel production on water resources remains less clear. As feedstock growth requires water and the type of water consumed may vary considerably from region to region, water use must be characterized with spatial resolution and on a fuel production basis. This report summarizes a study that assesses the impact of biofuel production on water resource use and water quality at county, state, and regional scales by developing a water footprint of biofuel produced from switchgrass and Miscanthus × giganteus via biochemical conversion.

  18. Elucidating and alleviating impacts of lignocellulose-derived microbial inhibitors on Clostridium beijerinckii during fermentation of Miscanthus giganteus to butanol.

    PubMed

    Zhang, Yan; Ezeji, Thaddeus Chukwuemeka

    2014-10-01

    Fermentation of liquid hot water (LHW) pretreated Miscanthus giganteus (MG) by Clostridium beijerinckii NCIMB 8052 was investigated towards understanding the toxicity of lignocellulose-derived inhibitors to solventogenic Clostridium species vis-à-vis butanol production. While C. beijerinckii NCIMB 8052 did not grow in undiluted MG hydrolysate-based fermentation medium, supplementation of this medium with Calcium carbonate enabled the growth of C. beijerinckii NCIMB 8052 and production of butanol. Using high-performance liquid chromatography (HPLC) and spectrophotometric assays, LHW-pretreated MG was found to contain lignocellulose-derived microbial inhibitory compounds; some of which were transformed by exponentially growing C. beijerinckii to less inhibitory compounds during fermentation. Contrary to all expectations, the reduction product of furfural, furfuryl alcohol, inhibited butanol production by C. beijerinckii by more than 16 %. Collectively, these results provide new insights into why lignocellulosic biomass hydrolysates are recalcitrant to fermentation to biofuels and chemicals.

  19. In vitro study of magnesium-calcite biomineralization in the skeletal materials of the seastar Pisaster giganteus.

    PubMed

    Gayathri, Subramanyam; Lakshminarayanan, Rajamani; Weaver, James C; Morse, Daniel E; Kini, R Manjunatha; Valiyaveettil, Suresh

    2007-01-01

    The mechanisms of formation of biogenic magnesium-rich calcite remain an enigma. Here we present ultrastructural and compositional details of ossicles from the seastar Pisaster giganteus (Echinodermata, Asteroidea). Powder X-ray diffraction, infrared spectroscopy and elemental analyses confirm that the ossicles are composed of magnesium-rich calcite, whilst also containing about 0.01 % (w/w) of soluble organic matrix (SOM) as an intracrystalline component. Amino acid analysis and N-terminal sequencing revealed that this mixture of intracrystalline macromolecules consists predominantly of glycine-rich polypeptides. In vitro calcium carbonate precipitation experiments indicate that the SOM accelerates the conversion of amorphous calcium carbonate (ACC) into its final crystalline product. From this observation and from the discovery of ACC in other closely related taxa, it is suggested that substitution of magnesium into the calcite lattice through a transient precursor phase may be a universal phenomenon prevalent across the phylum echinodermata.

  20. Arthromitus (Bacillus cereus) symbionts in the cockroach Blaberus giganteus: dietary influences on bacterial development and population density

    NASA Technical Reports Server (NTRS)

    Feinberg, L.; Jorgensen, J.; Haselton, A.; Pitt, A.; Rudner, R.; Margulis, L.

    1999-01-01

    The filamentous spore-forming bacterium Arthromitus, discovered in termites, millipedes, sow bugs and other soil-dwelling arthropods by Leidy (1850), is the intestinal stage of Bacillus cereus. We extend the range of Arthromitus habitats to include the hindgut of Blaberus giganteus, the large tropical American cockroach. The occurrence and morphology of the intestinal form of the bacillus were compared in individual cockroaches (n=24) placed on four different diet regimes: diurnally maintained insects fed (1) dog food, (2) soy protein only, (3)purified cellulose only, and (4) a dog food-fed group maintained in continuous darkness. Food quality exerted strong influence on population densities and developmental stages of the filamentous bacterium and on fecal pellet composition. The most dramatic rise in Arthromitus populations, defined as the spore-forming filament intestinal stage, occurred in adult cockroaches kept in the dark on a dog food diet. Limited intake of cellulose or protein alone reduced both the frequency of Arthromitus filaments and the rate of weight gain of the insects. Spores isolated from termites, sow bugs, cockroaches and moths, grown on various hard surfaces display a branching mobility and resistance to antibiotics characteristic to group I Bacilli whose members include B. cereus, B. circulans, B. alvei and B. macerans. DNA isolated from pure cultures of these bacilli taken from the guts of Blaberus giganteus (cockroach), Junonia coenia (moth), Porcellio scaber (sow bug) and Cryptotermes brevis (termite) and subjected to Southern hybridization with a 23S-5S B. subtilis ribosomal sequence probe verified that they are indistinguishable from laboratory strains of Bacillus cereus.

  1. Arthromitus (Bacillus cereus) symbionts in the cockroach Blaberus giganteus: dietary influences on bacterial development and population density

    NASA Technical Reports Server (NTRS)

    Feinberg, L.; Jorgensen, J.; Haselton, A.; Pitt, A.; Rudner, R.; Margulis, L.

    1999-01-01

    The filamentous spore-forming bacterium Arthromitus, discovered in termites, millipedes, sow bugs and other soil-dwelling arthropods by Leidy (1850), is the intestinal stage of Bacillus cereus. We extend the range of Arthromitus habitats to include the hindgut of Blaberus giganteus, the large tropical American cockroach. The occurrence and morphology of the intestinal form of the bacillus were compared in individual cockroaches (n=24) placed on four different diet regimes: diurnally maintained insects fed (1) dog food, (2) soy protein only, (3)purified cellulose only, and (4) a dog food-fed group maintained in continuous darkness. Food quality exerted strong influence on population densities and developmental stages of the filamentous bacterium and on fecal pellet composition. The most dramatic rise in Arthromitus populations, defined as the spore-forming filament intestinal stage, occurred in adult cockroaches kept in the dark on a dog food diet. Limited intake of cellulose or protein alone reduced both the frequency of Arthromitus filaments and the rate of weight gain of the insects. Spores isolated from termites, sow bugs, cockroaches and moths, grown on various hard surfaces display a branching mobility and resistance to antibiotics characteristic to group I Bacilli whose members include B. cereus, B. circulans, B. alvei and B. macerans. DNA isolated from pure cultures of these bacilli taken from the guts of Blaberus giganteus (cockroach), Junonia coenia (moth), Porcellio scaber (sow bug) and Cryptotermes brevis (termite) and subjected to Southern hybridization with a 23S-5S B. subtilis ribosomal sequence probe verified that they are indistinguishable from laboratory strains of Bacillus cereus.

  2. Arthromitus (Bacillus cereus) symbionts in the cockroach Blaberus giganteus: dietary influences on bacterial development and population density.

    PubMed

    Feinberg, L; Jorgensen, J; Haselton, A; Pitt, A; Rudner, R; Margulis, L

    1999-01-01

    The filamentous spore-forming bacterium Arthromitus, discovered in termites, millipedes, sow bugs and other soil-dwelling arthropods by Leidy (1850), is the intestinal stage of Bacillus cereus. We extend the range of Arthromitus habitats to include the hindgut of Blaberus giganteus, the large tropical American cockroach. The occurrence and morphology of the intestinal form of the bacillus were compared in individual cockroaches (n=24) placed on four different diet regimes: diurnally maintained insects fed (1) dog food, (2) soy protein only, (3)purified cellulose only, and (4) a dog food-fed group maintained in continuous darkness. Food quality exerted strong influence on population densities and developmental stages of the filamentous bacterium and on fecal pellet composition. The most dramatic rise in Arthromitus populations, defined as the spore-forming filament intestinal stage, occurred in adult cockroaches kept in the dark on a dog food diet. Limited intake of cellulose or protein alone reduced both the frequency of Arthromitus filaments and the rate of weight gain of the insects. Spores isolated from termites, sow bugs, cockroaches and moths, grown on various hard surfaces display a branching mobility and resistance to antibiotics characteristic to group I Bacilli whose members include B. cereus, B. circulans, B. alvei and B. macerans. DNA isolated from pure cultures of these bacilli taken from the guts of Blaberus giganteus (cockroach), Junonia coenia (moth), Porcellio scaber (sow bug) and Cryptotermes brevis (termite) and subjected to Southern hybridization with a 23S-5S B. subtilis ribosomal sequence probe verified that they are indistinguishable from laboratory strains of Bacillus cereus.

  3. Hatching success in salamanders and chorus frogs at two sites in Colorado, USA: Effects of acidic deposition and climate

    USGS Publications Warehouse

    Muths, E.; Campbell, D.H.; Corn, P.S.

    2003-01-01

    The snowpack in the vicinity of the Mount Zirkel Wilderness Area is among the most acidic in the western United States. We analyzed water chemistry and examined hatching success in tiger salamanders and chorus frogs at ponds there and at nearby Rabbit Ears Pass (Dumont) to determine whether acid deposition affects amphibians or their breeding habitats at these potentially sensitive locations. We found a wide range of acid neutralizing capacity among ponds within sites; the minimum pH recorded during the experiment was 5.4 at one of 12 ponds with all others at pH ??? 5.7. At Dumont, hatching success for chorus frogs was greater in ponds with low acid neutralizing capacity; however, lowest pHs were >5.8. At current levels of acid deposition, weather and pond characteristics are likely more important than acidity in influencing hatching success in amphibian larvae at these sites.

  4. The scintillating fiber tracker and the opto-electronic readout system of the CHORUS neutrino oscillation experiment

    SciTech Connect

    Rondeshagen, Dirk

    1998-11-09

    A scintillating fiber tracker system consisting of about 1.1 million fibers has been constructed successfully and is operational in the CHORUS neutrino oscillation experiment at CERN. The tracker system composes of a target tracker and a magnetic spectrometer. The target tracker consists of 8 tracker planes with 4 projections each, and the magnetic spectrometer consists of an air-core magnet and 3 tracker planes. The design, the performance and the opto-electronic readout system are described.

  5. Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves

    NASA Astrophysics Data System (ADS)

    Miyoshi, Y.; Saito, S.; Seki, K.; Nishiyama, T.; Kataoka, R.; Asamura, K.; Katoh, Y.; Ebihara, Y.; Sakanoi, T.; Hirahara, M.; Oyama, S.; Kurita, S.; Santolik, O.

    2015-09-01

    We investigate the origin of the fine structure of the energy spectrum of precipitating electrons for the pulsating aurora (PsA) observed by the low-altitude Reimei satellite. The Reimei satellite achieved simultaneous observations of the optical images and precipitating electrons of the PsA from satellite altitude (~620 km) with resolution of 40 ms. The main modulation of precipitation, with a few seconds, and the internal modulations, with a few hertz, that are embedded inside the main modulations are identified above ~3 keV. Moreover, stable precipitations at ~1 keV are found for the PsA. A "precipitation gap" is discovered between two energy bands. We identify the origin of the fine structure of the energy spectrum for the precipitating electrons using the computer simulation on the wave-particle interaction between electrons and chorus waves. The lower band chorus (LBC) bursts cause the main modulation of energetic electrons, and the generation and collapse of the LBC bursts determines on-off switching of the PsA. A train of rising tone elements embedded in the LBC bursts drives the internal modulations. A close set of upper band chorus (UBC) waves causes the stable precipitations at ~1 keV. We show that a wave power gap around the half gyrofrequency at the equatorial plane in the magnetosphere between LBC and UBC reduces the loss rate of electrons at the intermediate energy range, forming a gap of precipitating electrons in the ionosphere.

  6. Urea is not a universal cryoprotectant among hibernating anurans: evidence from the freeze-tolerant boreal chorus frog (Pseudacris maculata).

    PubMed

    Higgins, Steven A; Swanson, David L

    2013-02-01

    Freeze-tolerant organisms accumulate a diversity of low molecular weight compounds to combat negative effects of ice formation. Previous studies of anuran freeze tolerance have implicated urea as a cryoprotectant in the wood frog (Lithobates sylvatica). However, a cryoprotective role for urea has been identified only for wood frogs, though urea accumulation is an evolutionarily conserved mechanism for coping with osmotic stress in amphibians. To identify whether multiple solutes are involved in freezing tolerance in the boreal chorus frog (Pseudacris maculata), we examined seasonal and freezing-induced variation in several potential cryoprotectants. We further tested for a cryoprotective role for urea by comparing survival and recovery from freezing in control and urea-loaded chorus frogs. Tissue levels of glucose, urea, and glycerol did not vary significantly among seasons for heart, liver, or leg muscle. Furthermore, no changes in urea or glycerol levels were detected with exposure to freezing temperatures in these tissues. Urea-loading increased tissue urea concentrations, but failed to enhance freezing survival or facilitate recovery from freezing in chorus frogs in this study, suggesting little role for urea as a natural cryoprotectant in this species. These data suggest that urea may not universally serve as a primary cryoprotectant among freeze-tolerant, terrestrially hibernating anurans.

  7. Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

    DOE PAGES

    Jaynes, A. N.; Lessard, M. R.; Takahashi, K.; ...

    2015-10-28

    Theory and observations have linked equatorial VLF waves with pulsating aurora for decades, invoking the process of pitch angle scattering of tens of keV electrons in the equatorial magnetosphere. Recently published satellite studies have strengthened this argument, by showing strong correlation between pulsating auroral patches and both lower-band chorus and tens of keV electron modulation in the vicinity of geosynchronous orbit. Additionally, a previous link has been made between Pc4–5 compressional pulsations and modulation of whistler-mode chorus using Time History of Events and Macroscale Interactions during Substorms. In the current study, we present simultaneous in situ observations of structured chorusmore » waves and an apparent field line resonance (in the Pc4–5 range) as a result of a substorm injection, observed by Van Allen Probes, along with ground-based observations of pulsating aurora. We demonstrate the likely scenario being one of substorm-driven Pc4–5 ULF pulsations modulating chorus waves, and thus providing the driver for pulsating particle precipitation into the Earth's atmosphere. Interestingly, the modulated chorus wave and ULF wave periods are well correlated, with chorus occurring at half the periodicity of the ULF waves. We also show, for the first time, a particular few-Hz modulation of individual chorus elements that coincides with the same modulation in a nearby pulsating aurora patch. As a result, such modulation has been noticed as a high-frequency component in ground-based camera data of pulsating aurora for decades and may be a result of nonlinear chorus wave interactions in the equatorial region.« less

  8. PENGUIn/AGO and THEMIS conjugate observations of whistler mode chorus waves in the dayside uniform zone under steady solar wind and quiet geomagnetic conditions

    NASA Astrophysics Data System (ADS)

    Keika, Kunihiro; Spasojevic, Maria; Li, Wen; Bortnik, Jacob; Miyoshi, Yoshizumi; Angelopoulos, Vassilis

    2012-07-01

    We perform a case study of conjugate observations of whistler mode chorus waves on the dayside made on 26 July 2008 by three THEMIS spacecraft and ground-based ELF/VLF receivers at the Automatic Geophysical Observatories (AGO) in Antarctica supported by the U.S. Polar Experiment Network for Geospace Upper-atmosphere Investigations (PENGUIn) project. The dayside chorus waves were excited during a period of no substorm activity with geomagnetic indices indicating quiet conditions (Dst ˜ -10 nT; AE < 200 nT). The solar wind dynamic pressure was almost constant during the chorus wave intensification. Conjugate observations in the outer magnetosphere confirm that the chorus intensification was localized within the radial distance R = 7-10 RE near noon (12.5 < MLT < 13.5 h). The waves persisted for at least 1.5 h in the same location, where field lines are not accompanied by off-equatorial minimum-B pockets but rather exhibit nearly zero dB/ds, the field-aligned gradient in B-magnitude, over a wide range of magnetic latitudes (˜±20°). The location did not seem to corotate with the Earth or drift with the energetic electrons. The chorus waves consisted of discrete, rising tone elements, propagating away from the magnetic equator, quasi-parallel to the ambient magnetic field (wave-normal angles < 20°). We conclude that the long-lasting, localized, quiet time dayside chorus amplification was due to the nearly zero dB/ds conditions that occur naturally in the dayside uniform zone (DUZ), the transition region between the near-Earth dipole and the compressed, off-equatorial double-minimum field configuration found closer to the magnetopause. We thus suggest that the magnetic field configuration in the dayside outer magnetosphere plays a key role in the generation of dayside chorus waves under quiet geomagnetic conditions.

  9. Pectinase production by Aspergillus giganteus in solid-state fermentation: optimization, scale-up, biochemical characterization and its application in olive-oil extraction.

    PubMed

    Ortiz, Gastón E; Ponce-Mora, María C; Noseda, Diego G; Cazabat, Gabriela; Saravalli, Celina; López, María C; Gil, Guillermo P; Blasco, Martín; Albertó, Edgardo O

    2017-02-01

    The application of pectinases in industrial olive-oil processes is restricted by its production cost. Consequently, new fungal strains able to produce higher pectinase titers are required. The aim of this work was to study the capability of Aspergillus giganteus NRRL10 to produce pectinolytic enzymes by SSF and evaluate the application of these in olive-oil extraction. A. giganteus was selected among 12 strains on the basis of high pectinolytic activity and stability. A mixture composed by wheat bran, orange, and lemon peels was selected as the best substrate for enzyme production. Statistical analyses of the experimental design indicated that pH, temperature, and CaCl2 are the main factors that affect the production. Subsequently, different aeration flows were tested in a tray reactor; the highest activity was achieved at 20 L min(-1) per kilogram of dry substrate (kgds). Finally, the pectinolytic enzymes from A. giganteus improved the oil yield and rheological characteristics without affecting oil chemical properties.

  10. The evaluation of growth and phytoextraction potential of Miscanthus x giganteus and Sida hermaphrodita on soil contaminated simultaneously with Cd, Cu, Ni, Pb, and Zn.

    PubMed

    Kocoń, Anna; Jurga, Beata

    2017-02-01

    One of the cheapest, environmentally friendly methods for cleaning an environment polluted by heavy metals is phytoextraction. It builds on the uptake of pollutants from the soil by the plants, which are able to grow under conditions of high concentrations of toxic metals. The aim of this work was to assess the possibility of growing and phytoextraction potential of Miscanthus x giganteus and Sida hermaphrodita cultivated on two different soils contaminated with five heavy metals simultaneously: Cd, Cu, Ni, Pb, and Zn. A 3-year microplot experiment with two perennial energy crops, M. x giganteus and S. hermaphrodita, was conducted in the experimental station of IUNG-PIB in Poland (5° 25' N, 21° 58 'E), in the years of 2008-2010. Miscanthus was found more tolerant to concomitant soil contamination with heavy metals and produced almost double biomass than Sida in all three tested years, independent of soil type. Miscanthus collected greater amount of heavy metals (except for cadmium) in the biomass than Sida. Both energy crops absorb high levels of zinc, lower levels of lead, copper, and nickel, and absorbed cadmium at least, generally more metals were taken from the sandy soil, where plants also yielded better. Photosynthesis net rate of Miscanthus was on average 40% higher compared to Sida. Obtained results indicate that M. x giganteus and S. hermaphrodita can successfully be grown on moderately contaminated soil with heavy metals.

  11. Contact zone dynamics during early stages of speciation in a chorus frog (Pseudacris crucifer)

    PubMed Central

    Stewart, K A; Austin, J D; Zamudio, K R; Lougheed, S C

    2016-01-01

    Characterizing the genetic and behavioural consequences of contact between previously geographically isolated lineages provides insights into the mechanisms underlying diversification and ultimately speciation. The spring peeper (Pseudacris crucifer) is a widespread Nearctic chorus frog with six divergent mitochondrial DNA (mtDNA) lineages, many of which came into secondary contact during the Holocene. We examined genetics, morphology, advertisement calls and female preference for two lineages that began diverging in allopatry in the Pliocene and now overlap in southwestern Ontario, Canada. We found non-coincident clines in mtDNA and nuclear DNA, mirroring directionality of premating isolation barriers. We also found divergence in a range of traits between these two lineages, displacement in male call attributes and female preference for calls of their natal lineage in sympatry. Hybrids were morphologically distinct from both parental lineages, but hybrid male calls were acoustically intermediate. Female hybrids showed asymmetrical preference for Eastern male calls. These results considered together provide evidence of either unidirectional hybridization or selection against hybrids, potentially implying reproductive character displacement. Our work demonstrates the utility of integrated, multi-character approaches to understanding the processes of divergence and the nature of speciation. PMID:26626576

  12. Contact zone dynamics during early stages of speciation in a chorus frog (Pseudacris crucifer).

    PubMed

    Stewart, K A; Austin, J D; Zamudio, K R; Lougheed, S C

    2016-02-01

    Characterizing the genetic and behavioural consequences of contact between previously geographically isolated lineages provides insights into the mechanisms underlying diversification and ultimately speciation. The spring peeper (Pseudacris crucifer) is a widespread Nearctic chorus frog with six divergent mitochondrial DNA (mtDNA) lineages, many of which came into secondary contact during the Holocene. We examined genetics, morphology, advertisement calls and female preference for two lineages that began diverging in allopatry in the Pliocene and now overlap in southwestern Ontario, Canada. We found non-coincident clines in mtDNA and nuclear DNA, mirroring directionality of premating isolation barriers. We also found divergence in a range of traits between these two lineages, displacement in male call attributes and female preference for calls of their natal lineage in sympatry. Hybrids were morphologically distinct from both parental lineages, but hybrid male calls were acoustically intermediate. Female hybrids showed asymmetrical preference for Eastern male calls. These results considered together provide evidence of either unidirectional hybridization or selection against hybrids, potentially implying reproductive character displacement. Our work demonstrates the utility of integrated, multi-character approaches to understanding the processes of divergence and the nature of speciation.

  13. Interactions of energetic electron bursts and whistler-mode chorus wave emissions: Survey of event characteristics

    NASA Astrophysics Data System (ADS)

    Roeder, J. L.; Fennell, J. F.; Schriver, D.; Echterling, N.

    2016-12-01

    Wave-particle interaction events have been detected by the Van Allen Probes at L 4-6 during the recovery of substorm plasma injections. We present a survey of similar events observed for the entire mission to date, and discus the implications of the measured particle and wave parameters for the interaction mechanisms. Fennell et al. [J. Geophys. Res., 2014] reported details of an event on January 13, 2013. Quasiperiodic bursts of 16-40 keV electrons in very narrow, oblique ranges of pitch angles (75-80° and 100-105°) were observed by MagEIS to correlate well with simultaneous bursts of upper-band, whistler-mode chorus waves. Electrostatic electron cyclotron harmonic (ECH) waves were also detected but exhibited little correlation with the electron bursts. Simultaneous electron observations by the HOPE plasma instrument at that energy show features consistent with the MagEIS data superimposed on a moderately anisotropic background plasma. The two Van Allen Probe spacecraft were approximately 0.3 hours apart in the post-midnight MLT sector. Spacecraft A, at earlier local times, detected the same time sequence of bursts 2 minutes prior to the observations by Spacecraft B. This relatively long delay corresponds to a propagation velocity of approximately 25 km/s. The observational survey focuses on the energy and pitch angle of the electron bursts, the anisotropy of the background plasma, the wave frequency and wave normal direction, and geomagnetic conditions during the events.

  14. Factors influencing survival and mark retention in postmetamorphic boreal chorus frogs

    USGS Publications Warehouse

    Swanson, Jennifer E; Bailey, Larissa L.; Muths, Erin L.; Funk, W. Chris

    2013-01-01

    The ability to track individual animals is crucial in many field studies and often requires applying marks to captured individuals. Toe clipping has historically been a standard marking method for wild amphibian populations, but more recent marking methods include visual implant elastomer and photo identification. Unfortunately, few studies have investigated the influence and effectiveness of marking methods for recently metamorphosed individuals and as a result little is known about this life-history phase for most amphibians. Our focus was to explore survival probabilities, mark retention, and mark migration in postmetamorphic Boreal Chorus Frogs (Psuedacris maculata) in a laboratory setting. One hundred forty-seven individuals were assigned randomly to two treatment groups or a control group. Frogs in the first treatment group were marked with visual implant elastomer, while frogs in the second treatment group were toe clipped. Growth and mortality were recorded for one year and resulting data were analyzed using known-fate models in Program MARK. Model selection results suggested that survival probabilities of frogs varied with time and showed some variation among marking treatments. We found that frogs with multiple toes clipped on the same foot had lower survival probabilities than individuals in other treatments, but individuals can be marked by clipping a single toe on two different feet without any mark loss or negative survival effects. Individuals treated with visual implant elastomer had a mark migration rate of 4% and mark loss rate of 6%, and also showed very little negative survival impacts relative to control individuals.

  15. Effects of Drift-Shell Splitting by Chorus Waves on Radiation Belt Electrons

    NASA Astrophysics Data System (ADS)

    Chan, A. A.; Zheng, L.; O'Brien, T. P., III; Tu, W.; Cunningham, G.; Elkington, S. R.; Albert, J.

    2015-12-01

    Drift shell splitting in the radiation belts breaks all three adiabatic invariants of charged particle motion via pitch angle scattering, and produces new diffusion terms that fully populate the diffusion tensor in the Fokker-Planck equation. Based on the stochastic differential equation method, the Radbelt Electron Model (REM) simulation code allows us to solve such a fully three-dimensional Fokker-Planck equation, and to elucidate the sources and transport mechanisms behind the phase space density variations. REM has been used to perform simulations with an empirical initial phase space density followed by a seed electron injection, with a Tsyganenko 1989 magnetic field model, and with chorus wave and ULF wave diffusion models. Our simulation results show that adding drift shell splitting changes the phase space location of the source to smaller L shells, which typically reduces local electron energization (compared to neglecting drift-shell splitting effects). Simulation results with and without drift-shell splitting effects are compared with Van Allen Probe measurements.

  16. The observed and simulated saturation characteristics of whistler-mode chorus waves

    NASA Astrophysics Data System (ADS)

    An, Xin; Yue, Chao; Bortnik, Jacob; Decyk, Viktor; Li, Wen; Thorne, Richard

    2016-10-01

    The evolution of the whistler anisotropy instability relevant to whistler-mode chorus waves in the Earth's inner magnetosphere is studied using kinetic simulations and is compared with satellite observations. The electron distribution is constrained by the whistler anisotropy instability to a marginal stability state and presents an upper bound of electron anisotropy, which agrees remarkably well with satellite observations. The electron beta β∥ e separates whistler waves into two groups: (i) quasi-parallel whistler waves for β∥ e > 0.02 and (ii) oblique whistler waves close to the resonance cone for β∥ e < 0.02 . Landau damping is important in the saturation and relaxation stage of the oblique whistler wave growth. The magnetic amplitude of whistler waves roughly scales with the electron beta β∥ e, shown in both simulations and satellite observations. These results suggest the critical role of electron beta β∥ e in determining the whistler wave properties in the inner magnetosphere. The research was funded by the Department of Energy and the National Science Foundation by Grant DE-SC0010578 and was also funded by NASA Grant NNX16AG21G.

  17. Impact of the chorus environment on temporal processing of advertisement calls by gray treefrogs

    NASA Astrophysics Data System (ADS)

    Schwartz, Joshua; Huth, Kenneth; Lasker, Jeffrey

    2004-05-01

    Male gray treefrogs advertise for mates using calls that consist of a series of pulses. Pulse duration, interpulse interval, and pulse shape determine whether a call is recognized as a conspecific signal by females. Females use call rate and call pulse number to assess relative calling performance by males, and prefer males that display high calling efforts. However, within choruses call overlap among males and background noise can compromise the ability of females to detect and correctly interpret temporal information in calls. Phonotaxis tests using calls suffering from different patterns of overlap or with internal gaps were used to investigate specific consequences of interference and masking as well as mechanisms that might alleviate such problems. Our data indicate that females do not employ a process analogous to phonemic restoration to ``fill in'' missing call segments; however, if a sufficient percent of call elements fall within species-specific ranges, females may ignore call anomalies. Additional findings are generally consistent with those from a recent study on anuran auditory midbrain neurons that count and indicate that inappropriate pulse intervals can reset the pulse counting process. [Work supported by NSF and a Pace University Eugene M. Lang Research Fellowship.

  18. Rapid increase in relativistic electron flux controlled by nonlinear phase trapping of whistler chorus elements

    NASA Astrophysics Data System (ADS)

    Saito, Shinji; Miyoshi, Yoshizumi; Seki, Kanako

    2016-07-01

    Wave-particle interactions with whistler chorus waves are believed to provide a primary acceleration for electrons in the outer radiation belt. Previous models for flux enhancement of the radiation belt have assumed the stochastic process as a diffusion manner of successive random-phase interactions, but physical mechanisms for the acceleration are not fully incorporated in these models because of the lack of a nonlinear scattering process. Here we report rapid increase in relativistic electron flux by using an innovative computer simulation model that incorporates not only diffusive process but also nonlinear scattering processes. The simulations show that three types of scattering simultaneously occur, which are diffusive, phase trapping, and phase bunching. It is found that the phase trapping is the most efficient mechanism to produce the MeV electrons rapidly in the scattering processes. The electrons are accelerated from 400 keV to over 1 MeV in time scale less than 60 s. On the other hand, as the phase trapping is suppressed by the breaking of relative phase angle between waves and gyrating electrons during the interaction, the increase of electron flux at MeV energy is clearly reduced. Our simulations conclude that the phase-trapping process causes a significant effect for the increase in relativistic electron flux and suggest that a quasi-linear diffusion model is not always valid to fully describe the relativistic electron acceleration.

  19. Impact of the chorus environment on temporal processing of advertisement calls by gray treefrogs

    NASA Astrophysics Data System (ADS)

    Schwartz, Joshua; Huth, Kenneth; Lasker, Jeffrey

    2001-05-01

    Male gray treefrogs advertise for mates using calls that consist of a series of pulses. Pulse duration, interpulse interval, and pulse shape determine whether a call is recognized as a conspecific signal by females. Females use call rate and call pulse number to assess relative calling performance by males, and prefer males that display high calling efforts. However, within choruses call overlap among males and background noise can compromise the ability of females to detect and correctly interpret temporal information in calls. Phonotaxis tests using calls suffering from different patterns of overlap or with internal gaps were used to investigate specific consequences of interference and masking as well as mechanisms that might alleviate such problems. Our data indicate that females do not employ a process analogous to phonemic restoration to ``fill in'' missing call segments; however, if a sufficient percent of call elements fall within species-specific ranges, females may ignore call anomalies. Additional findings are generally consistent with those from a recent study on anuran auditory midbrain neurons that count and indicate that inappropriate pulse intervals can reset the pulse counting process. [Work supported by NSF and a Pace University Eugene M. Lang Research Fellowship.

  20. A Theoretical Picture of the Combined Effects of Drift-Shell Splitting and Chorus-Wave Interactions on Radiation Belt Electrons

    NASA Astrophysics Data System (ADS)

    Chan, A. A.; Zheng, L.; O'Brien, T. P., III; Tu, W.; Cunningham, G.; Albert, J.; Elkington, S. R.

    2016-12-01

    Recent simulations made with the REM (Radiation belt Electron Model, a 3D diffusion code that uses stochastic differential equation methods) show that an enhancement produced by strong chorus-wave interactions will typically be reduced when drift-shell splitting is included in the calculations. Including drift-shell splitting causes the diffusion tensor in adiabatic-invariant coordinates to become fully populated, and at first sight the increased complexity of the corresponding diffusion equation makes it difficult to find a simple interpretation of the simulation results. However, by exploiting a relatively little-known property of matrices under congruence transformations called Sylvester's Law of Inertia, plus some generic features of radiation belt dynamics in the presence of strong chorus waves, a useful theoretical picture emerges that predicts the decreased enhancements and provides useful physical insights into the effects of drift-shell splitting in the presence of chorus waves.

  1. Purification and Characterization of a Unique Pectin Lyase from Aspergillus giganteus Able to Release Unsaturated Monogalacturonate during Pectin Degradation

    PubMed Central

    Carmona, Eleonora Cano

    2014-01-01

    A pectin lyase, named PLIII, was purified to homogeneity from the culture filtrate of Aspergillus giganteus grown in submerged culture containing orange peel waste as carbon source. PLIII was able to digest apple pectin and citrus pectins with different degrees of methyl esterification. Interestingly, the PLIII activity was stimulated in the presence of some divalent cations including Pb2+ and was not significantly affected by Hg2+. Like other pectin lyases, PLIII is stimulated by but is not dependent on Ca2+. The main soluble product released during the degradation of pectic substances promoted by the PLIII is compatible with an unsaturated monogalacturonate. PLIII is a unique enzyme able to release unsaturated monogalacturonate as the only soluble product during the degradation of pectic substances; therefore, PLIII was classified as an exo-pectin lyase. To our knowledge, this is the first characterization of an exo-pectin lyase. The PLIII described in this work is potentially useful for ethanol production from pectin-rich biomass, besides other common applications for alkaline pectinases like preparation of textile fibers, coffee and tea fermentation, vegetable oil extraction, and the treatment of pulp in papermaking. PMID:25610636

  2. An investigation of the topography of the lymphatic system of the grey kangaroo (Macropus giganteus). 1. The superficial lymphatic system.

    PubMed Central

    Hopwood, P R

    1988-01-01

    The superficial lymphatic system of the grey kangaroo, Macropus giganteus is described. The description is based on dissections of 130 eastern grey kangaroos. The most significant difference found between the superficial lymphatic drainage pattern of kangaroos and that of the domestic species was the existence of large inguino-axillary lymphatic trunks in the kangaroo. Thus in the kangaroo, instead of lymph passing from the inguinal lymphocentre to the lumbar lymphatic trunks as is the situation in the domestic animals, lymph passes from the inguinal lymphocentre to the axillary lymphocentre. Apart from the lymph draining from the head and ventral neck (which passes to the superficial cervical lymphocentre) and lymph which may pass from the superficial lymphatic vessels to deeper lymphatic vessels, all the superficial lymphatic drainage of the kangaroo passes through the axillary lymphocentre. From the viewpoint of the meat inspection of the carcasses of kangaroos taken as game meat animals, pathology of the axillary lymphocentre may reflect disease in a much wider range of body regions than it would in a domestic animal. PMID:3198478

  3. Studies on productivity and characterization of polygalacturonase from Aspergillus giganteus submerged culture using citrus pectin and orange waste.

    PubMed

    Pedrolli, Danielle Biscaro; Gomes, Eleni; Monti, Rubens; Carmona, Eleonora Cano

    2008-02-01

    Polygalacturonases are part of the group of enzymes involved in pectin degradation. The aim of this work was to investigate some of the factors affecting polygalacturonase production by an Aspergillus giganteus strain and to characterize this pectinolytic activity. Several carbon sources, both pure substances and natural substrates, were tested in standing cultures, and the best results were obtained with orange bagasse and purified citrus pectin. On citrus pectin as sole carbon source, the highest extracellular activity (9.5 U/ml and 40.6 U/mg protein) was obtained in 4.5-day-old cultures shaken at 120 rpm, pH 3.5 and 30 degrees C, while on orange bagasse, the highest extracellular activity (48.5 U/ml and 78.3 U/mg protein) was obtained in 3.5-day-old cultures shaken at 120 rpm, pH 6.0 and 30 degrees C. Optimal polygalacturonase activity was observed in assays conducted at pH 5.5-6.5 and 55-60 degrees C. The activity showed good thermal stability, with half-lives of 90 and 30 min when incubated at 55 and 60 degrees C, respectively. High stability was observed from pH 4.5 to 8.5; more than 90% of the activity remained after 24 h in this pH range.

  4. Study of wave-particle interactions of VLF/ELF chorus waves observed at subauroral latitudes

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Shiokawa, K.; Miyoshi, Y.; Ozaki, M.; Ishizaka, K.; Yagitani, S.; Connors, M. G.

    2012-12-01

    One of the mechanisms that cause energetic particle precipitation at low latitude side of auroral zone, such as pulsating auroras, is the VLF/ELF waves generated around magnetic equator which modulate particle precipitation through wave-particle interaction. In this model, correlations between pulsating auroras and VLF/ELF waves observed at ground are expected. Indeed, examples of such good correlations were reported previously (Tsuruda et al., 1981). In those days, however, it was difficult to analyze the frequency characteristics and wave forms in detail, since all data were in analog recordings. Therefore, we made a campaign observation of high-time resolution measurements of auroras and VLF/ELF waves at Athabasca (54.72N, 246.69E, MLAT=61.3) and Fort Vermillion (58.38N, 243.99E, MLAT=64.5), using two loop antennas(100kHz sampling), several auroral cameras(30-100Hz sampling) and induction magnetometers(64Hz sampling) for February 16-27, 2012. In this campaign, various types of chorus waves were observed, i.e., Q-P emissions with repeating periods of 20-60 seconds, rising/falling tones for which the emission frequency varies in a few seconds, patchy high-frequency burst waves, and so on. In order to investigate waveparticle interaction of these waves, we closely compare these VLF/ELF waves with the data of energetic particle precipitation obtained from all-sky cameras and riometers in Athabasca and Meanook (54.61N, 246.65E, MLAT=61.47). We also investigate local magnetic field variations and ULF wave variations to identify the cause of temporal variation of VLF/ELF waves.

  5. Widespread legacy brine contamination from oil production reduces survival of chorus frog larvae.

    PubMed

    Hossack, Blake R; Puglis, Holly J; Battaglin, William A; Anderson, Chauncey W; Honeycutt, R Ken; Smalling, Kelly L

    2017-08-29

    Advances in drilling techniques have facilitated a rapid increase in hydrocarbon extraction from energy shales, including the Williston Basin in central North America. This area overlaps with the Prairie Pothole Region, a region densely populated with wetlands that provide numerous ecosystem services. Historical (legacy) disposal practices often released saline co-produced waters (brines) with high chloride concentrations, affecting wetland water quality directly or persisting in sediments. Despite the potential threat of brine contamination to aquatic habitats, there has been little research into its ecological effects. We capitalized on a gradient of legacy brine-contaminated wetlands in northeast Montana to conduct laboratory experiments to assess variation in survival of larval Boreal Chorus Frogs (Pseudacris maculata) reared on sediments from 3 local wetlands and a control source. To help provide environmental context for the experiment, we also measured chloride concentrations in 6 brine-contaminated wetlands in our study area, including the 2 contaminated sites used for sediment exposures. Survival of frog larvae during 46- and 55-day experiments differed by up to 88% among sediment sources (Site Model) and was negatively correlated with potential chloride exposure (Chloride Model). Five of the 6 contaminated wetlands exceeded the U.S. EPA acute benchmark for chloride in freshwater (860 mg/L) and all exceeded the chronic benchmark (230 mg/L). However, the Wetland Site model explained more variation in survival than the Chloride Model, suggesting that chloride concentration alone does not fully reflect the threat of contamination to aquatic species. Because the profiles of brine-contaminated sediments are complex, further surveys and experiments are needed across a broad range of conditions, especially where restoration or remediation actions have reduced brine-contamination. Information provided by this study can help quantify potential ecological threats

  6. Developmental and Post-Eruptive Defects in Molar Enamel of Free-Ranging Eastern Grey Kangaroos (Macropus giganteus) Exposed to High Environmental Levels of Fluoride

    PubMed Central

    Kierdorf, Uwe; Death, Clare; Hufschmid, Jasmin; Witzel, Carsten; Kierdorf, Horst

    2016-01-01

    Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus) from the same high-fluoride area using light microscopy and backscattered electron imaging in the scanning electron microscope. The fluorotic enamel exhibited a brownish to blackish discolouration due to post-eruptive infiltration of stains from the oral cavity and was less resistant to wear than normally mineralized enamel of kangaroos from low-fluoride areas. Developmental defects of enamel included enamel hypoplasia and a pronounced hypomineralization of the outer (sub-surface) enamel underneath a thin rim of well-mineralized surface enamel. While the hypoplastic defects denote a disturbance of ameloblast function during the secretory stage of amelogenesis, the hypomineralization is attributed to an impairment of enamel maturation. In addition to hypoplastic defects, the fluorotic molars also exhibited numerous post-eruptive enamel defects due to the flaking-off of portions of the outer, hypomineralized enamel layer during mastication. The macroscopic and histopathological lesions in fluorotic enamel of M. giganteus match those previously described for placental mammals. It is therefore concluded that there exist no principal differences in the pathogenic mechanisms of dental fluorosis between marsupial and placental mammals. The regular occurrence of hypomineralized, opaque outer enamel in the teeth of M. giganteus and other macropodids must be considered in the differential diagnosis of dental fluorosis in these species. PMID:26895178

  7. Developmental and Post-Eruptive Defects in Molar Enamel of Free-Ranging Eastern Grey Kangaroos (Macropus giganteus) Exposed to High Environmental Levels of Fluoride.

    PubMed

    Kierdorf, Uwe; Death, Clare; Hufschmid, Jasmin; Witzel, Carsten; Kierdorf, Horst

    2016-01-01

    Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus) from the same high-fluoride area using light microscopy and backscattered electron imaging in the scanning electron microscope. The fluorotic enamel exhibited a brownish to blackish discolouration due to post-eruptive infiltration of stains from the oral cavity and was less resistant to wear than normally mineralized enamel of kangaroos from low-fluoride areas. Developmental defects of enamel included enamel hypoplasia and a pronounced hypomineralization of the outer (sub-surface) enamel underneath a thin rim of well-mineralized surface enamel. While the hypoplastic defects denote a disturbance of ameloblast function during the secretory stage of amelogenesis, the hypomineralization is attributed to an impairment of enamel maturation. In addition to hypoplastic defects, the fluorotic molars also exhibited numerous post-eruptive enamel defects due to the flaking-off of portions of the outer, hypomineralized enamel layer during mastication. The macroscopic and histopathological lesions in fluorotic enamel of M. giganteus match those previously described for placental mammals. It is therefore concluded that there exist no principal differences in the pathogenic mechanisms of dental fluorosis between marsupial and placental mammals. The regular occurrence of hypomineralized, opaque outer enamel in the teeth of M. giganteus and other macropodids must be considered in the differential diagnosis of dental fluorosis in these species.

  8. Deadly Lessons.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1996-01-01

    In Fox River Grove, Illinois, 7 teenagers were killed the morning of October 25, 1995, when a 620-ton commuter train crashed into the rear end of their school bus. School, transportation, and safety officials have focused on three areas: train crossings and signals, bus-driver training, and school-bus construction. Lists 10 vital lessons for…

  9. Lessons Learned.

    ERIC Educational Resources Information Center

    Haynes, Norris M.

    1998-01-01

    Discusses lessons learned in the implementation of James Comer's School Development Program including: (1) leadership; (2) overcoming resistance to change; (3) time required for change; (4) creating a supportive climate; (5) staff commitment and staff time; (6) personnel and staff training; (7) parent involvement; (8) connecting school and…

  10. Lessons Learned

    ERIC Educational Resources Information Center

    Maurer, Matthew J.

    2010-01-01

    Have you participated in professional development (PD) programs that never met your expectations? Have you found it difficult to find a program that fits well with your academic and pedagogical needs? If so, the author shares your sentiment. In this article, he describes three lessons learned while developing and conducting a PD partnership…

  11. Lessons Learned.

    ERIC Educational Resources Information Center

    Haynes, Norris M.

    1998-01-01

    Discusses lessons learned in the implementation of James Comer's School Development Program including: (1) leadership; (2) overcoming resistance to change; (3) time required for change; (4) creating a supportive climate; (5) staff commitment and staff time; (6) personnel and staff training; (7) parent involvement; (8) connecting school and…

  12. Deadly Lessons.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1996-01-01

    In Fox River Grove, Illinois, 7 teenagers were killed the morning of October 25, 1995, when a 620-ton commuter train crashed into the rear end of their school bus. School, transportation, and safety officials have focused on three areas: train crossings and signals, bus-driver training, and school-bus construction. Lists 10 vital lessons for…

  13. Cytotoxicity and modes of action of four Cameroonian dietary spices ethno-medically used to treat cancers: Echinops giganteus, Xylopia aethiopica, Imperata cylindrica and Piper capense.

    PubMed

    Kuete, Victor; Sandjo, Louis P; Wiench, Benjamin; Efferth, Thomas

    2013-08-26

    Echinops giganteus, Imperata cylindrica, Piper capense and Xylopia aethiopica are four medicinal spices used in Cameroon to treat cancers. The above plants previously displayed cytotoxicity against leukemia CCRF-CEM and CEM/ADR5000 cell lines as well as human pancreatic MiaPaCa-2 cells. The present study aims at emphasizing the study of the cytotoxicity and the modes of action of the above plants on a panel of ten cancer cell lines including various sensitive and drug-resistant phenotypes. The study has been extended to the isolation of the bioactive constituents from Echinops giganteus. The cytotoxicity of the extracts was determined using a resazurin reduction assay, whereas the caspase-Glo assay was used to detect the activation of caspases 3/7, caspase 8 and caspase 9 in cells treated with the four extracts. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells, analysis of mitochondrial membrane potential (MMP) as well as measurement of reactive oxygen species (ROS). The four tested extracts inhibited the proliferation of all tested cancer cell lines including sensitive and drug-resistant phenotypes. Collateral sensitivity of cancer cells to the extract of Echinops giganteus was generally better than to doxorubicin. The recorded IC50 ranges were 3.29 µg/mL [against human knockout clones HCT116 (p53(-/-)) colon cancer cells] to 14.32 µg/mL (against human liver hepatocellular carcinoma HepG2 cells) for the crude extract from Echinops giganteus, 4.17 µg/mL (against breast cancer cells transduced with control vector MDA-MB231 cells) to 19.45 µg/mL (against MDA-MB-231 BCRP cells) for that of Piper capense, 4.11 µg/mL (against leukemia CCRF-CEM cells) to 30.60 µg/mL (against leukemia HL60AR cells) for Xylopia aethiopica, 3.28 µg/mL [against HCT116 (p53(-/-)) cells] to 33.43 µg/mL (against HepG2 cells) for Imperata cylindica and 0.11 µg/mL (against CCRF-CEM cells) to 132.47 µg/mL (against HL60AR cells) for doxorubicin. The four

  14. Method for direct detection of pitch angle scattering of energetic electrons caused by whistler mode chorus emissions

    NASA Astrophysics Data System (ADS)

    Kitahara, M.; Katoh, Y.

    2016-06-01

    The Wave-Particle Interaction Analyzer (WPIA), a new instrument proposed by Fukuhara et al. (2009), measures the relative phase angle between the wave magnetic field vector and the velocity vector of each particle and calculates the energy exchange from waves to particles. In this study, we expand its applicability by proposing a method of using the WPIA to directly detect pitch angle scattering of resonant particles by plasma waves by calculating the g values. The g value is defined as the accumulation value of the Lorentz force acting on each particle and indicates the lost momentum of waves. We apply the proposed method to the results of a one-dimensional electron hybrid simulation reproducing the generation of whistler mode chorus emissions around the magnetic equator. Using the wave and particle data obtained at fixed observation points assumed in the simulation system, we conduct a pseudo-observation of the simulation result using the WPIA and analyze the g values. Our analysis yielded significant values indicating the strong pitch angle scattering for electrons in the kinetic energy and pitch angle ranges satisfying the cyclotron resonance condition with the reproduced chorus emissions. The results of this study demonstrate that the proposed method enables us to directly and quantitatively identify the location at which pitch angle scattering occurs in the simulation system and that the method can be applied to the results of space-based observations by the forthcoming Exploration of energization and Radiation in Geospace (ERG) satellite.

  15. Refuge or Reservoir? The Potential Impacts of the Biofuel Crop Miscanthus x giganteus on a Major Pest of Maize

    PubMed Central

    Spencer, Joseph L.; Raghu, S.

    2009-01-01

    Background Interest in the cultivation of biomass crops like the C4 grass Miscanthus x giganteus (Miscanthus) is increasing as global demand for biofuel grows. In the US, Miscanthus is promoted as a crop well-suited to the Corn Belt where it could be cultivated on marginal land interposed with maize and soybean. Interactions (direct and indirect) of Miscanthus, maize, and the major Corn Belt pest of maize, the western corn rootworm, (Diabrotica virgifera virgifera LeConte, WCR) are unknown. Adding a perennial grass/biomass crop to this system is concerning since WCR is adapted to the continuous availability of its grass host, maize (Zea mays). Methodology/Principal Findings In a greenhouse and field study, we investigated WCR development and oviposition on Miscanthus. The suitability of Miscanthus for WCR development varied across different WCR populations. Data trends indicate that WCR populations that express behavioural resistance to crop rotation performed as well on Miscanthus as on maize. Over the entire study, total adult WCR emergence from Miscanthus (212 WCR) was 29.6% of that from maize (717 WCR). Adult dry weight was 75–80% that of WCR from maize; female emergence patterns on Miscanthus were similar to females developing on maize. There was no difference in the mean no. of WCR eggs laid at the base of Miscanthus and maize in the field. Conclusions/Significance Field oviposition and significant WCR emergence from Miscanthus raises many questions about the nature of likely interactions between Miscanthus, maize and WCR and the potential for Miscanthus to act as a refuge or reservoir for Corn Belt WCR. Responsible consideration of the benefits and risks associated with Corn Belt Miscanthus are critical to protecting an agroecosystem that we depend on for food, feed, and increasingly, fuel. Implications for European agroecosystems in which Miscanthus is being proposed are also discussed in light of the WCR's recent invasion into Europe. PMID:20016814

  16. Influence of light and nitrogen on the photosynthetic efficiency in the C4 plant Miscanthus × giganteus.

    PubMed

    Ma, Jian-Ying; Sun, Wei; Koteyeva, Nuria K; Voznesenskaya, Elena; Stutz, Samantha S; Gandin, Anthony; Smith-Moritz, Andreia M; Heazlewood, Joshua L; Cousins, Asaph B

    2017-01-01

    There are numerous studies describing how growth conditions influence the efficiency of C4 photosynthesis. However, it remains unclear how changes in the biochemical capacity versus leaf anatomy drives this acclimation. Therefore, the aim of this study was to determine how growth light and nitrogen availability influence leaf anatomy, biochemistry and the efficiency of the CO2 concentrating mechanism in Miscanthus × giganteus. There was an increase in the mesophyll cell wall surface area but not cell well thickness in the high-light (HL) compared to the low-light (LL) grown plants suggesting a higher mesophyll conductance in the HL plants, which also had greater photosynthetic capacity. Additionally, the HL plants had greater surface area and thickness of bundle-sheath cell walls compared to LL plants, suggesting limited differences in bundle-sheath CO2 conductance because the increased area was offset by thicker cell walls. The gas exchange estimates of phosphoenolpyruvate carboxylase (PEPc) activity were significantly less than the in vitro PEPc activity, suggesting limited substrate availability in the leaf due to low mesophyll CO2 conductance. Finally, leakiness was similar across all growth conditions and generally did not change under the different measurement light conditions. However, differences in the stable isotope composition of leaf material did not correlate with leakiness indicating that dry matter isotope measurements are not a good proxy for leakiness. Taken together, these data suggest that the CO2 concentrating mechanism in Miscanthus is robust under low-light and limited nitrogen growth conditions, and that the observed changes in leaf anatomy and biochemistry likely help to maintain this efficiency.

  17. Establishment, Growth, and Yield Potential of the Perennial Grass Miscanthus × Giganteus on Degraded Coal Mine Soils

    PubMed Central

    Jeżowski, Stanisław; Mos, Michal; Buckby, Sam; Cerazy-Waliszewska, Joanna; Owczarzak, Wojciech; Mocek, Andrzej; Kaczmarek, Zygmunt; McCalmont, Jon P.

    2017-01-01

    Miscanthus × giganteus is a giant C4 grass native to Asia. Unlike most C4 species, it is relatively cold tolerant due to adaptations across a wide range of altitudes. These grasses are characterized by high productivity and low input requirements, making them excellent candidates for bioenergy feedstock production. The aim of this study was to investigate the potential for growing Miscanthus on extremely marginal soils, degraded by open lignite (brown coal) mining. Field experiments were established within three blocks situated on waste heaps originating from the lignite mine. Analyses were conducted over the first 3 years following Miscanthus cultivation, focusing on the effect of organic and mineral fertilization on crop growth, development and yield in this extreme environment. The following levels of fertilization were implemented between the blocks: the control plot with no fertilization (D0), a plot with sewage sludge (D1), a plot with an identical amount of sewage sludge plus one dose of mineral fertilizer (D2) and a plot with an identical amount of sewage sludge plus a double dose of mineral fertilizer (D3). Crop development and characteristics (plant height, tillering, and biomass yield [dry matter]) were measured throughout the study period and analyzed using Analysis of Variance (ANOVA). Significant differences were apparent between plant development and 3rd year biomass production over the course of the study (0.964 kg plant-1 for DO compared to 1.503 kg plant-1 for D1). Soil analyses conducted over the course of the experiment showed that organic carbon levels within the soil increased significantly following the cultivation of Miscanthus, and overall, pH decreased. With the exception of iron, macronutrient concentrations remained stable throughout. The promising yields and positive effects of Miscanthus on the degraded soil suggests that long term plantations on land otherwise unsuitable for agriculture may prove to be of great environmental and

  18. Persistent organic pollutants in blood samples of Southern Giant Petrels (Macronectes giganteus) from the South Shetland Islands, Antarctica.

    PubMed

    Colabuono, Fernanda I; Vander Pol, Stacy S; Huncik, Kevin M; Taniguchi, Satie; Petry, Maria V; Kucklick, John R; Montone, Rosalinda C

    2016-09-01

    Seabirds play an important role as top consumers in the food web and can be used as biomonitors of exposure to pollutants. Contamination studies involving non-destructive sampling methods are of considerable importance, allowing better evaluation of the levels of pollutants and their toxic effects. In the present study, organohalogen contaminants were analyzed in 113 blood samples from Southern Giant Petrel (Macronectes giganteus) adults and chicks collected in the austral summer of 2011/2012 and 2012/2013 from colonies on Elephant and Livingston Islands, South Shetland, Antarctica. Polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), mirex, dichlorodiphenyltrichloroetane and derivatives (DDTs) and chlordanes were detected in all birds, whereas polybrominated diphenyl ethers (PBDEs) were not detected in any blood samples. No significant differences were found in organochlorine levels between sampling events. Adults exhibited significantly higher levels than chicks, except for PeCB. PCBs, HCB, mirex and DDTs were statistically similar in males and females from Elephant Island. Females on Livingston Island exhibited higher HCB values than males, but no sex differences were found regarding other organochlorines. The similarity in organochlorine levels between sexes in birds with very marked sexual segregation in feeding habits during the breeding season may indicate that significant amounts of contaminants are acquired during migration to lower latitudes, when the diets of males and females are similar. Birds sampled on Livingston Island exhibited significantly lower levels of PCBs, HCB, DDTs, mirex and chlordanes in comparison to those on Elephant Island, which could be the result of distinct foraging patterns between the two colonies. Organochlorine levels were similar between years in birds captured in two consecutive breeding seasons. Blood samples from Southern Giant Petrels adults and chicks proved to be useful for the comparison

  19. Contribution of Miscanthus x giganteus root exudates to the biostimulation of PAH degradation: an in vitro study.

    PubMed

    Técher, Didier; Laval-Gilly, Philippe; Henry, Sonia; Bennasroune, Amar; Formanek, Pavel; Martinez-Chois, Claudia; D'Innocenzo, Marielle; Muanda, François; Dicko, Amadou; Rejšek, Klement; Falla, Jairo

    2011-09-15

    Phytoremediation is considered as a promising and cost-effective method to enhance bioremediation of polluted soils. Exudation of plant root secondary metabolites similar to organic pollutants may induce the expression of microbial degradative enzymes and favour cometabolism of xenobiotics. We investigated the contribution of Miscanthus x giganteus root exudates in the biostimulation of PAH-degradation. This perennial grass was chosen because of its capability to grow on polluted soils and its high biomass production for non-food purposes. First, the impact of cometabolism phenomena was evaluated on the selective enrichment of pyrene-degrading bacterial consortia. The identification of each isolated strains following incubation with pyrene only, "pyrene+phenanthrene", "pyrene+salycilate" or "pyrene+diesel fuel" showed a varying bacterial diversity and pyrene-degrading ability, depending on the co-substrate used. Then, a microplate assay was designed, based on the simultaneous measurement of bacterial consortia growth and degradation activity, in the presence of PAH and total root exudates. Results showed that i) the addition of root exudates was efficient for promoting bacterial growth, ii) but a selective enrichment of PAH-degraders compared to aliphatic ones could be clearly demonstrated, thereby conducing to an enhanced PAH catabolism. The identification of plant secondary metabolites showed the presence of a broad range of flavonoid-derived compounds that could play a role in cometabolic processes. Microplate assays with the two major molecules, quercetin and rutin, suggested a partial involvement of these compounds in biostimulation processes. Further investigations with the other identified secondary metabolites (apigenin, isovitexin, catechin, gallic and caffeic acid) should provide more information on the exudate-PAH cometabolic degradation phenomenon.

  20. Refuge or reservoir? The potential impacts of the biofuel crop Miscanthus x giganteus on a major pest of maize.

    PubMed

    Spencer, Joseph L; Raghu, S

    2009-12-16

    Interest in the cultivation of biomass crops like the C4 grass Miscanthus x giganteus (Miscanthus) is increasing as global demand for biofuel grows. In the US, Miscanthus is promoted as a crop well-suited to the Corn Belt where it could be cultivated on marginal land interposed with maize and soybean. Interactions (direct and indirect) of Miscanthus, maize, and the major Corn Belt pest of maize, the western corn rootworm, (Diabrotica virgifera virgifera LeConte, WCR) are unknown. Adding a perennial grass/biomass crop to this system is concerning since WCR is adapted to the continuous availability of its grass host, maize (Zea mays). In a greenhouse and field study, we investigated WCR development and oviposition on Miscanthus. The suitability of Miscanthus for WCR development varied across different WCR populations. Data trends indicate that WCR populations that express behavioural resistance to crop rotation performed as well on Miscanthus as on maize. Over the entire study, total adult WCR emergence from Miscanthus (212 WCR) was 29.6% of that from maize (717 WCR). Adult dry weight was 75-80% that of WCR from maize; female emergence patterns on Miscanthus were similar to females developing on maize. There was no difference in the mean no. of WCR eggs laid at the base of Miscanthus and maize in the field. Field oviposition and significant WCR emergence from Miscanthus raises many questions about the nature of likely interactions between Miscanthus, maize and WCR and the potential for Miscanthus to act as a refuge or reservoir for Corn Belt WCR. Responsible consideration of the benefits and risks associated with Corn Belt Miscanthus are critical to protecting an agroecosystem that we depend on for food, feed, and increasingly, fuel. Implications for European agroecosystems in which Miscanthus is being proposed are also discussed in light of the WCR's recent invasion into Europe.

  1. Biosolids and distillery effluent amendment to Irish Miscanthus ×giganteus plantations: impacts on groundwater and soil.

    PubMed

    Galbally, P; Fagan, C; Ryan, D; Finnan, J; Grant, J; McDonnell, K

    2012-01-01

    It is necessary to determine the risk of water pollution arising from amendment of organic by-products (OBs) to energy crops under Irish conditions. Therefore, the impact of landspreading two OBs on the quality of groundwater underlying plantations of Miscanthus X giganteus was assessed. Municipal biosolids and distillery effluent (DE) were spread annually (for 4 yr) on six 0.117-ha treatment plots at rates of 100, 50, and 0%. The 100% rate represented a maximum P load of 15 t ha(-1) as per Irish EPA regulation. Groundwater was sampled for 25 mo and tested for pH, electrical conductivity, NO(3)(-), orthophosphate (PO(4)(3-)), total soluble P, K(+), Cu, Cd, Cr, Pb, Ni, and Zn. Assessment of quality was based on comparison with Irish groundwater threshold values (GTVs). The study was limited to within-plot using a "well bottom" approach and did not investigate movement of groundwater plumes or vectors of percolation through the soil profile. Mean groundwater concentrations did not exceed GTVs during the sampling period for any species, with the exception of groundwater PO(4)(3-) in the 100% DE plot, which was almost double the GTV of 0.035 mg L(-1). There was no significant build-up of nutrients or heavy metals in groundwater (or soil) for any plot. Excessive PO(4)(3-) in the 100% DE plot groundwater is likely due to high background soil P, soil characteristics, and the occurrence of macropore/soil pore flow. These factors (particularly background soil P) should be assessed when determining suitable sites for land-spreading OBs. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Purification and pharmacological properties of eight sea anemone toxins from Anemonia sulcata, Anthopleura xanthogrammica, Stoichactis giganteus, and Actinodendron plumosum.

    PubMed

    Schweitz, H; Vincent, J P; Barhanin, J; Frelin, C; Linden, G; Hugues, M; Lazdunski, M

    1981-09-01

    Eight different polypeptide toxins from sea anemones of four different origins (Anemonia sulcata, Anthopleura xanthogrammica, Stoichactis giganteus, and Actinodendron plumosum) have been studied. Three of these toxins are new; the purification procedure for the five other ones has been improved. Sea anemone toxins were assayed (i) for their toxicity to crabs and mice, (ii) for their affinity for the specific sea anemone toxin receptor situated on the Na+ channels of rat brain synaptosomes, and (iii) for their capacity to increase, in synergy with veratridine, the rate of 22Na+ entry into neuroblastoma cells via the Na+ channel. Some of the toxins are more active on crustaceans, whereas others are more toxic to mammals. A very good correlation exists between the toxic activity to mice, the affinity of the toxin for the Na+ channel in rat brain synaptosomes, and the stimulating effect on 22 Na+ uptake by neuroblastoma cells. The observation has also been made that the most cationic toxins are also the most active on mammals and the least active on crustaceans. Toxicities (LD50) to mice of the most active sea anemone toxins and of the most active scorpion toxins are similar, and sea anemone toxins at high enough concentrations prevent binding of scorpion toxins to their receptor. However, scorpion toxins have affinities for the Na+ channel which are approximately 60 times higher than those found for the most active sea anemone toxins. Three sea anemone toxins appear to be more interesting than toxin II from A. sulcata (the "classical" sea anemone toxin) for studies of the Na+ channel structure and mechanism when the source of the channel is of a mammalian origin. Two of these three toxins can be radiolabeled with iodine while retaining their toxic activity; they appear to be useful tools for future biochemical studies of the Na+ channel.

  3. Dynamics of energetic electrons interacting with sub-packet chorus emissions in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Hiraga, R.; Omura, Y.

    2016-12-01

    The recent study has revealed RTA and URA processes, the acceleration of relativistic electrons by interaction with chorus emissions. The wave model, however, is found to require some updates based on the recent observations. We develop a new wave model compatible with the observations and study the particle motion under the influence of this new wave model. The most distinctive feature of the new model is its amplitude growth manner. The wave is excited near the equator and grows in amplitude as an absolute instability as a function of time. This amplitude growth is bounded by the optimum and threshold amplitudes. When the amplitude grows to reach the optimum amplitude, it drops down to the threshold value and repeats the growth with a saw-like shape defined as sub-packet wave. The sub-packet wave generated near the equator experiences the convective amplitude growth propagating to the higher latitude region. Since the group velocity of the wave propagation is a function of its frequency, a wave source generated and released from the equator at a certain time and a group velocity could be overtaken by another wave released at a later timing and hence a faster group velocity. In sub-packet case, this frequency value is further affected by the sub-packet amplitude wave form to make the process more complex. Into this new wave form, energetic electrons are inserted and their motions are examined. For example, a resonant electron can be entrapped by the wave, being accelerated and normally detrapped after a certain period of time, but there can be a possibility that the following sub-packet wave in a complex propagation manner coincidently entraps the electron to provide multiple accelerations. We injected a large number of electrons over a wide energy range from 10kev to 10Mev into the sub-packet wave to simulate the nonlinear dynamics of RTA and URA. The electrons motion or more precisely entrapping and detrapping processes are examined under various conditions.

  4. Heterogeneity and Glycan Masking of Cell Wall Microstructures in the Stems of Miscanthus x giganteus, and Its Parents M. sinensis and M. sacchariflorus

    PubMed Central

    Xue, Jie; Bosch, Maurice; Knox, J. Paul

    2013-01-01

    Plant cell walls, being repositories of fixed carbon, are important sources of biomass and renewable energy. Miscanthus species are fast growing grasses with a high biomass yield and they have been identified as potential bioenergy crops. Miscanthus x giganteus is the sterile hybrid between M. sinensis and M. sacchariflorus, with a faster and taller growth than its parents. In this study, the occurrence of cell wall polysaccharides in stems of Miscanthus species has been determined using fluorescence imaging with sets of cell wall directed monoclonal antibodies. Heteroxylan and mixed linkage-glucan (MLG) epitopes are abundant in stem cell walls of Miscanthus species, but their distributions are different in relation to the interfascicular parenchyma and these epitopes also display different developmental dynamics. Detection of pectic homogalacturonan (HG) epitopes was often restricted to intercellular spaces of parenchyma regions and, notably, the high methyl ester LM20 HG epitope was specifically abundant in the pith parenchyma cell walls of M. x giganteus. Some cell wall probes cannot access their target glycan epitopes because of masking by other polysaccharides. In the case of Miscanthus stems, masking of xyloglucan by heteroxylan and masking of pectic galactan by heteroxylan and MLG was detected in certain cell wall regions. Knowledge of tissue level heterogeneity of polysaccharide distributions and molecular architectures in Miscanthus cell wall structures will be important for both understanding growth mechanisms and also for the development of potential strategies for the efficient deconstruction of Miscanthus biomass. PMID:24312403

  5. Trypanosoma brucei Inhibition by Essential Oils from Medicinal and Aromatic Plants Traditionally Used in Cameroon (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea and Echinops giganteus)

    PubMed Central

    Ngahang Kamte, Stephane L.; Ranjbarian, Farahnaz; Campagnaro, Gustavo Daniel; Biapa Nya, Prosper C.; Mbuntcha, Hélène; Woguem, Verlaine; Womeni, Hilaire Macaire; Tapondjou, Léon Azefack; Giordani, Cristiano; Benelli, Giovanni; Hofer, Anders

    2017-01-01

    Essential oils are complex mixtures of volatile components produced by the plant secondary metabolism and consist mainly of monoterpenes and sesquiterpenes and, to a minor extent, of aromatic and aliphatic compounds. They are exploited in several fields such as perfumery, food, pharmaceutics, and cosmetics. Essential oils have long-standing uses in the treatment of infectious diseases and parasitosis in humans and animals. In this regard, their therapeutic potential against human African trypanosomiasis (HAT) has not been fully explored. In the present work, we have selected six medicinal and aromatic plants (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea, and Echinops giganteus) traditionally used in Cameroon to treat several disorders, including infections and parasitic diseases, and evaluated the activity of their essential oils against Trypanosma brucei TC221. Their selectivity was also determined with Balb/3T3 (mouse embryonic fibroblast cell line) cells as a reference. The results showed that the essential oils from A. indica, A. daniellii, and E. giganteus were the most active ones, with half maximal inhibitory concentration (IC50) values of 15.21, 7.65, and 10.50 µg/mL, respectively. These essential oils were characterized by different chemical compounds such as sesquiterpene hydrocarbons, monoterpene hydrocarbons, and oxygenated sesquiterpenes. Some of their main components were assayed as well on T. brucei TC221, and their effects were linked to those of essential oils. PMID:28684709

  6. Swimming Lessons

    ERIC Educational Resources Information Center

    Goldman, Arthur

    2006-01-01

    In this article, the author talks about his experience as an 11-year-old swimmer and shares the lessons he learned as a member of the swim team. In his experience as one of the slowest team members, he discovered that slow and steady does not win the race, and when the focus is only on achievement, one loses the value of failure. As an adult, he…

  7. Swimming Lessons

    ERIC Educational Resources Information Center

    Goldman, Arthur

    2006-01-01

    In this article, the author talks about his experience as an 11-year-old swimmer and shares the lessons he learned as a member of the swim team. In his experience as one of the slowest team members, he discovered that slow and steady does not win the race, and when the focus is only on achievement, one loses the value of failure. As an adult, he…

  8. Lessons in American Music

    ERIC Educational Resources Information Center

    Robinson Lindsay, Debra Kay

    2006-01-01

    "Lessons in American Music," by Debra Kay Robinson Lindsay, is a collection of lessons covering William Billings, Stephen Foster, Scott Joplin, and "The Star-Spangled Banner." This book is an all-in-one resource for teachers, offering lesson plans, activities, sheet music, and assessments. The set of lessons on William Billings will let your…

  9. Lesson Learning at JPL

    NASA Technical Reports Server (NTRS)

    Oberhettinger, David

    2011-01-01

    A lessons learned system is a hallmark of a mature engineering organization A formal lessons learned process can help assure that valuable lessons get written and published, that they are well-written, and that the essential information is "infused" into institutional practice. Requires high-level institutional commitment, and everyone's participation in gathering, disseminating, and using the lessons

  10. Lesson Learning at JPL

    NASA Technical Reports Server (NTRS)

    Oberhettinger, David

    2011-01-01

    A lessons learned system is a hallmark of a mature engineering organization A formal lessons learned process can help assure that valuable lessons get written and published, that they are well-written, and that the essential information is "infused" into institutional practice. Requires high-level institutional commitment, and everyone's participation in gathering, disseminating, and using the lessons

  11. Lessons in American Music

    ERIC Educational Resources Information Center

    Robinson Lindsay, Debra Kay

    2006-01-01

    "Lessons in American Music," by Debra Kay Robinson Lindsay, is a collection of lessons covering William Billings, Stephen Foster, Scott Joplin, and "The Star-Spangled Banner." This book is an all-in-one resource for teachers, offering lesson plans, activities, sheet music, and assessments. The set of lessons on William Billings will let your…

  12. Differences in the diurnal pattern of soil respiration under adjacent Miscanthus x giganteus and barley crops reveal potential flaws in accepted sampling strategies

    NASA Astrophysics Data System (ADS)

    Keane, James; Ineson, Phil

    2017-04-01

    Soil respiration (Rs) plays an important role in the global carbon cycle and contributes ca. 30% of global ecosystem respiration.However, for convenience, measurements used to compare Rs from different land uses, crops or management practices are often made between 09:00 and 16:00, with an implicit assumption that Rs is largely controlled by temperature. Three months' continuous data presented here show distinctly different diurnal patterns of Rs between barley (Hordeum vulgare) and Miscanthus x giganteus (Miscanthus) grown on adjacent fields. Maximum Rs in barley occurred during the afternoon and correlated with soil temperature, whereas Rs peaked in Miscanthus during the night and was significantly correlated with earlier levels of solar radiation, probably due to delays in translocation of recent photosynthate. Since daily mean Rs in Miscanthus coincided with levels 40% greater than the mean in barley, it is vital to select appropriate times to measure Rs if only single daily measurements are to be made.

  13. Relationships between soil parameters and physiological status of Miscanthus x giganteus cultivated on soil contaminated with trace elements under NPK fertilisation vs. microbial inoculation.

    PubMed

    Pogrzeba, Marta; Rusinowski, Szymon; Sitko, Krzysztof; Krzyżak, Jacek; Skalska, Aleksandra; Małkowski, Eugeniusz; Ciszek, Dorota; Werle, Sebastian; McCalmont, Jon Paul; Mos, Michal; Kalaji, Hazem M

    2017-06-01

    Crop growth and development can be influenced by a range of parameters, soil health, cultivation and nutrient status all play a major role. Nutrient status of plants can be enhanced both through chemical fertiliser additions (e.g. N, P, K supplementation) or microbial fixation and mobilisation of naturally occurring nutrients. With current EU priorities discouraging the production of biomass on high quality soils there is a need to investigate the potential of more marginal soils to produce these feedstocks and the impacts of soil amendments on crop yields within them. This study investigated the potential for Miscanthus x giganteus to be grown in trace element (TE)-contaminated soils, ideally offering a mechanism to (phyto)manage these contaminated lands. Comprehensive surveys are needed to understand plant-soil interactions under these conditions. Here we studied the impacts of two fertiliser treatments on soil physico-chemical properties under Miscanthus x giganteus cultivated on Pb, Cd and Zn contaminated arable land. Results covered a range of parameters, including soil rhizosphere activity, arbuscular mycorrhization (AM), as well as plant physiological parameters associated with photosynthesis, TE leaf concentrations and growth performance. Fertilization increased growth and gas exchange capacity, enhanced rhizosphere microbial activity and increased Zn, Mg and N leaf concentration. Fertilization reduced root colonisation by AMF and caused higher chlorophyll concentration in plant leaves. Microbial inoculation seems to be a promising alternative for chemical fertilizers, especially due to an insignificant influence on the mobility of toxic trace elements (particularly Cd and Zn). Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. The adhesive protein of Choromytilus chorus (Molina, 1782) and Aulacomya ater (Molina, 1782): a proline-rich and a glycine-rich polyphenolic protein.

    PubMed

    Burzio, L A; Saéz, C; Pardo, J; Waite, J H; Burzio, L O

    2000-06-15

    The adhesive polyphenolic proteins from Aulacomya ater and Choromytilus chorus with apparent molecular masses of 135000 and 105000, respectively, were digested with trypsin and the peptides produced resolved by reversed phase liquid chromatography. About 5 and 12 major peptides were obtained from the protein of A. ater and C. chorus, respectively. The major peptides were purified by reverse-phase chromatography and the amino acid sequence indicates that both polyphenolic proteins consisted of repeated sequence motifs in their primary structure. The major peptides of A. ater contain seven amino acids corresponding to the consensus sequence AGYGGXK, whereas the tyrosine was always found as 3, 4-dihydroxyphenylalanine (Dopa), the X residue in position 6 was either valine, leucine or isoleucine, and the carboxy terminal was either lysine or hydroxylysine. On the other hand, the major peptides of C. chorus ranged in size from 6 to 21 amino acids and the majority correspond to the consensus sequence AKPSKYPTGYKPPVK. Both proteins differ markedly in the sequence of their tryptic peptides, but they share the common characteristics of other adhesive proteins in having a tandem sequence repeat in their primary structure.

  15. ALOHA Cabled Observatory: Continuing lessons and results

    NASA Astrophysics Data System (ADS)

    Howe, B. M.; Lukas, R.

    2012-12-01

    Since June 2011, the ALOHA Cabled Observatory (ACO) is providing 1 kW power, 100 Mbs network communications and PPS timing to a seafloor node and instruments at 4728 m water depth 100 km north of Oahu. Station ALOHA is the field site of the Hawaii Ocean Time-series (HOT) program that has investigated physical and biogeochemical variability of the water column near-monthly since 1988. The abyssal near bottom acoustic Doppler profiler data are showing stronger than expected internal tide flows and turbulence 20-80 m above bottom. In this oligotrophic environment, the video camera has detected significant biological activity. Acoustic data collected on two hydrophones clearly show very high call density of baleen whales during September-May and sperm whale choruses spread throughout the year. Recent Navy exercises provided examples of anthropogenic sounds. We are also monitoring in real time an acoustic "heartbeat" signal from the nearby HOT Profiler mooring (M. Alford et al.). ACO operation over the last year continues to provide valuable lessons. Several failures occurred at or during deployment, including two ground faults that have isolated two CTDs, a fluorometer, and an acoustic modem from the system. Two independent LED light systems failed after 4 and 6 weeks. Most recently, the pressure sensor has failed perhaps due to loss of vacuum in the quartz crystal chamber. The one remaining conductivity/temperature sensor is episodically, but strongly, affected by thermal plume signatures from the nearby power supply. Understanding the reasons for these failures and limitations will be necessary to improve the methodologies for sustained long-term abyssal measurements. This will be well worth the effort, as suggested by the surprisingly rich video, ADCP, and acoustic data sets.

  16. Lesson Plans and Lessons Learned

    NASA Astrophysics Data System (ADS)

    Cliffe, J. A.; Whitlock, L. A.; Boyd, P. T.; Lochner, J. C.; Granger, K.

    1997-12-01

    For the past 18 months, responding to a growing demand by the public, the X-ray branch of the Laboratory for High- Energy Astrophysics has created a successful web-based education/outreach program aimed at K-12 students. The High- Energy Astrophysics Learning Center and StarChild were launched in 1996; since then the sites have also been put on CD-ROM and distributed to over ten thousand teachers nationwide. In the Fall of 1997, the "High-Energy Astrophysics Learning Center" was reincarnated as "Imagine the Universe!". The changes were brought about for a number of reasons, such as to expand the scope outside X-ray and and gamma-ray astronomy, to remove a name that often intimidated potential users, and to implement an abundance of user feedback. We present the new Imagine the Universe! web site and the lessons learned from our experience in the education/ outreach arena. Imagine the Universe! focuses on what scientists know about the structures in, and the evolution of, our Universe. It also investigates how scientists know these things, the remaining mysteries, and how answers might be found. At present, only the X-ray and gamma-ray approaches to these issues are active in the site. However, radio, microwave, infrared, ultraviolet, and cosmic ray information will be added over the next year. In keeping with the trend in education to base curriculum on national standards, all of the science topics presented are listed with the national mathematics and science standards to which they relate. The same is true of the revamped Teacher's Corner and the growing list of lesson plans found there. What works, what does not work, and the kind of feedback you get when you have a K-12 astronomy education web site will be presented.

  17. Lessons Learned

    PubMed Central

    Davis, Michaela

    2015-01-01

    The public health nurses’ scope of practice explicitly includes child protection within their role, which places them in a prime position to identify child protection concerns. This role compliments that of other professions and voluntary agenices who work with children. Public health nurses are in a privileged position as they form a relationship with the child’s parent(s)/guardian(s) and are able to see the child in its own environment, which many professionals cannot. Child protection in Ireland, while influenced by other countries, has progressed through a distinct pathway that streamlined protocols and procedures. However, despite the above serious failures have occurred in the Irish system, and inquiries over the past 20 years persistently present similar contributing factors, namely, the lack of standardized and comprehensive service responses. Moreover, poor practice is compounded by the lack of recognition of the various interactional processes taking place within and between the different agencies of child protection, leading to psychological barriers in communication. This article will explore the lessons learned for public health nurses practice in safeguarding children in the Republic of Ireland. PMID:27335944

  18. Giant Oyster Mushroom Pleurotus giganteus (Agaricomycetes) Enhances Adipocyte Differentiation and Glucose Uptake via Activation of PPARγ and Glucose Transporters 1 and 4 in 3T3-L1 Cells.

    PubMed

    Paravamsivam, Puvaneswari; Heng, Chua Kek; Malek, Sri Nurestri Abdul; Sabaratnam, Vikineswary; M, Ravishankar Ram; Kuppusamy, Umah Rani

    2016-01-01

    The edible mushroom Pleurotus giganteus was tested for its effect on adipocyte differentiation and glucose uptake activity in 3T3-L1 cells. The basidiocarps of P. giganteus were soaked in methanol to obtain a crude methanol extract and then fractionated to obtain an ethyl acetate extract. In this study, cell proliferation was measured using an MTT assay, lipid accumulation using an Oil Red O assay, and glucose uptake using a fluorescence glucose uptake assay. Gene expression was measured via real-time polymerase chain reaction analysis with TaqMan primer. Ethyl acetate extract significantly enhanced adipogenic differentiation and glucose uptake in 3T3-L1 adipocytes via the expression of sterol regulatory element-binding protein, peroxisome proliferator-activated receptor γ, and phos-phatidylinositol 3-kinase/Akt. Glucose uptake was facilitated by the highly expressed glucose transporters Glut1 and Glut4. Taken together, these results suggest that P. giganteus ethyl acetate extract has an insulin-sensitizing effect on adipocytes and has potential as an adjuvant for the management of type 2 diabetes.

  19. Mobile Lessons: Lessons Based on Geo-Referenced Information.

    ERIC Educational Resources Information Center

    Giroux, Sylvain; Moulin, Claude; Sanna, Raffaella; Pintus, Antonio

    The term "mobile lessons" is coined for lessons held outside of "artificial" environments, such as classrooms. During these lessons, all actors are mobile and must move to do the required tasks. Themes tackled in such lessons may be as varied as geography, history, ecology, and linguistics. The use of mobile lessons is not a…

  20. Lessons Learned in Engineering

    NASA Technical Reports Server (NTRS)

    Blair, J. C.; Ryan, R. S.; Schutzenhofer, L. A.

    2011-01-01

    This Contractor Report (CR) is a compilation of Lessons Learned in approximately 55 years of engineering experience by each James C. Blair, Robert S. Ryan, and Luke A. Schutzenhofer. The lessons are the basis of a course on Lessons Learned that has been taught at Marshall Space Flight Center. The lessons are drawn from NASA space projects and are characterized in terms of generic lessons learned from the project experience, which are further distilled into overarching principles that can be applied to future projects. Included are discussions of the overarching principles followed by a listing of the lessons associated with that principle. The lesson with sub-lessons are stated along with a listing of the project problems the lesson is drawn from, then each problem is illustrated and discussed, with conclusions drawn in terms of Lessons Learned. The purpose of this CR is to provide principles learned from past aerospace experience to help achieve greater success in future programs, and identify application of these principles to space systems design. The problems experienced provide insight into the engineering process and are examples of the subtleties one experiences performing engineering design, manufacturing, and operations.

  1. Whistler-mode chorus waves in the dayside outer magnetosphere under quiet geomagnetic conditions: PENGUIn-AGO and THEMIS conjugate observations

    NASA Astrophysics Data System (ADS)

    Keika, K.; Spasojevic, M.; Li, W.; Bortnik, J.; Miyoshi, Y.; Angelopoulos, V.; Gerrard, A. J.

    2011-12-01

    We perform a case study of whistler-mode chorus waves in the dayside outer (L>7) magnetosphere under quiet geomagnetic conditions. We use simultaneous conjugate observations made at 1230-1930 UT on 26 July 2008 by three THEMIS spacecraft and ground-based VLF receivers at two automatic geophysical observatories (AGO) in Antarctica supported by the US Polar Experiment Network for Geospace Upper-atmosphere Investigations (PENGUIn) project. Solar wind dynamic pressure was constant and weak (~1 nPa); the Dst index was around -10 nT; and the AE index showed weak activity (<200 nT). VLF wave intensification was observed by THEMIS A, D, and E. Waveform data from THEMIS A show that the waves were intensified in a frequency range of 500-800 Hz (0.3-0.4 fce) and circularly right-handed polarized. Filter bank data show that all three THEMIS probes observed wave intensification in the 287-1240 Hz range around noon and 6-9 RE near the equatorial plane. VLF signals at the AGO P2 station (AP2: MLAT = -76.6 deg.; MLT = UT-3.5h) were intensified in the frequency range of 500-1000 Hz. At the AGO P3 station (AP3: MLAT = -83.63 deg., MLT = UT-2h), VLF signals were intensified in the same frequency range; the increase rate was smaller than at AP2. The VLF wave intensification peaked around noon. The AGO AP2 and AP3 stations are mapped along field lines to the outer magnetosphere; the mapped locations in the equatorial plane are 9-10 RE and 10-11 RE around noon, respectively. We also confirm, from fluxgate magnetometer data, that AP2 and AP3 were equatorward of the open-closed boundary. The observed chorus waves were intensified in narrow ranges of MLT and radial distance. We conclude that the localized intensification continued for at least 1.5 hours. We examine the configuration of magnetic field lines in which the THEMIS spacecraft and the AGO stations reside during the wave intensification, and find that the intensification occurred when field lines have small gradient along a field

  2. Apollo Lesson Sampler: Apollo 13 Lessons Learned

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael A.

    2008-01-01

    This CD-ROM contains a two-part case study of the Apollo 13 accident. The first lesson contains an overview of the electrical system hardware on the Apollo spacecraft, providing a context for the details of the oxygen tank explosion, and the failure chain reconstruction that led to the conditions present at the time of the accident. Given this background, the lesson then covers the tank explosion and immediate damage to the spacecraft, and the immediate response of Mission Control to what they saw. Part 2 of the lesson picks up shortly after the explosion of the oxygen tank on Apollo 13, and discusses how Mission Control gained insight to and understanding of the damage in the aftermath. Impacts to various spacecraft systems are presented, along with Mission Control's reactions and plans for in-flight recovery leading to a successful entry. Finally, post-flight vehicle changes are presented along with the lessons learned.

  3. Apollo Lesson Sampler: Apollo 13 Lessons Learned

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael A.

    2008-01-01

    This CD-ROM contains a two-part case study of the Apollo 13 accident. The first lesson contains an overview of the electrical system hardware on the Apollo spacecraft, providing a context for the details of the oxygen tank explosion, and the failure chain reconstruction that led to the conditions present at the time of the accident. Given this background, the lesson then covers the tank explosion and immediate damage to the spacecraft, and the immediate response of Mission Control to what they saw. Part 2 of the lesson picks up shortly after the explosion of the oxygen tank on Apollo 13, and discusses how Mission Control gained insight to and understanding of the damage in the aftermath. Impacts to various spacecraft systems are presented, along with Mission Control's reactions and plans for in-flight recovery leading to a successful entry. Finally, post-flight vehicle changes are presented along with the lessons learned.

  4. Effects of hydroperiod duration on survival, developmental rate, and size at metamorphosis in boreal chorus frog tadpoles (Pseudacris maculata)

    USGS Publications Warehouse

    Amburgey, Staci; Funk, W. Chris; Murphy, Melanie; Muths, Erin

    2012-01-01

    Understanding the relationship between climate-driven habitat conditions and survival is key to preserving biodiversity in the face of rapid climate change. Hydroperiod—the length of time water is in a wetland—is a critical limiting habitat variable for amphibians as larvae must metamorphose before ponds dry. Changes in precipitation and temperature patterns are affecting hydroperiod globally, but the impact of these changes on amphibian persistence is poorly understood. We studied the responses of Boreal Chorus Frog (Pseudacris maculata) tadpoles to simulated hydroperiods (i.e., water level reductions) in the laboratory using individuals collected from ponds spanning a range of natural hydroperiods (Colorado Front Range, USA). To assess the effects of experimental hydroperiod reduction, we measured mortality, time to metamorphosis, and size at metamorphosis. We found that tadpoles grew at rates reflecting the hydroperiods of their native ponds, regardless of experimental treatment. Tadpoles from permanent ponds metamorphosed faster than those from ephemeral ponds across all experimental treatments, a pattern which may represent a predation selection gradient or countergradient variation in developmental rates. Size at metamorphosis did not vary across experimental treatments. Mortality was low overall but varied with pond of origin. Our results suggest that adaptation to local hydroperiod and/or predation and temperature conditions is important in P. maculata. Moreover, the lack of a plastic response to reduced hydroperiods suggests that P. maculata may not be able to metamorphose quickly enough to escape drying ponds. These results have important implications for amphibian persistence in ponds predicted to dry more quickly due to rapid climate change.

  5. Comparison of the enzymatic digestibility of physically and chemically pretreated selected line of diploid-Miscanthus sinensis Shiozuka and triploid-M.×giganteus.

    PubMed

    Hideno, Akihiro; Kawashima, Ayato; Anzoua, Kossonou Guillaume; Yamada, Toshihiko

    2013-10-01

    The diploid Miscanthus sinensis "Shiozuka" which was selected as a high-biomass producing line, and the triploid M. × giganteus (M×G) were treated by ball milling (physical treatment) and alkaline hydrogen peroxide treatment (AHP; chemical treatment), and their structural sugar compositions and enzymatic digestibility were compared. The structural sugar content of Shiozuka was moderate and lower than that of M×G. The Klason lignin content of Shiozuka was also lower than that of M×G. However, Shiozuka was sensitive to ball milling and AHP treatment; ball milled and AHP-treated Shiozuka had higher enzymatic digestibility than ball milled and AHP-treated M×G. Shiozuka would be promising feedstock to obtain fermentable sugars with low energy consumption. Finally, enzymes for the hydrolysis of chemically treated Miscanthus were isolated from Trichoderma reesei ATCC 66589 and Penicillium pinophilum. The sugar yield could be increased by enzymatic hydrolysis of AHP-treated samples with NaOH and H2O2 and the isolated enzymes.

  6. A retrospective study of Babesia macropus associated with morbidity and mortality in eastern grey kangaroos (Macropus giganteus) and agile wallabies (Macropus agilis).

    PubMed

    Donahoe, Shannon L; Peacock, Christopher S; Choo, Ace Y L; Cook, Roger W; O'Donoghue, Peter; Crameri, Sandra; Vogelnest, Larry; Gordon, Anita N; Scott, Jenni L; Rose, Karrie

    2015-08-01

    This is a retrospective study of 38 cases of infection by Babesia macropus, associated with a syndrome of anaemia and debility in hand-reared or free-ranging juvenile eastern grey kangaroos (Macropus giganteus) from coastal New South Wales and south-eastern Queensland between 1995 and 2013. Infection with B. macropus is recorded for the first time in agile wallabies (Macropus agilis) from far north Queensland. Animals in which B. macropus infection was considered to be the primary cause of morbidity had marked anaemia, lethargy and neurological signs, and often died. In these cases, parasitised erythrocytes were few or undetectable in peripheral blood samples but were sequestered in large numbers within small vessels of visceral organs, particularly in the kidney and brain, associated with distinctive clusters of extraerythrocytic organisms. Initial identification of this piroplasm in peripheral blood smears and in tissue impression smears and histological sections was confirmed using transmission electron microscopy and molecular analysis. Samples of kidney, brain or blood were tested using PCR and DNA sequencing of the 18S ribosomal RNA and heat shock protein 70 gene using primers specific for piroplasms. The piroplasm detected in these samples had 100% sequence identity in the 18S rRNA region with the recently described Babesia macropus in two eastern grey kangaroos from New South Wales and Queensland, and a high degree of similarity to an unnamed Babesia sp. recently detected in three woylies (Bettongia penicillata ogilbyi) in Western Australia.

  7. A retrospective study of Babesia macropus associated with morbidity and mortality in eastern grey kangaroos (Macropus giganteus) and agile wallabies (Macropus agilis)

    PubMed Central

    Donahoe, Shannon L.; Peacock, Christopher S.; Choo, Ace Y.L.; Cook, Roger W.; O'Donoghue, Peter; Crameri, Sandra; Vogelnest, Larry; Gordon, Anita N.; Scott, Jenni L.; Rose, Karrie

    2015-01-01

    This is a retrospective study of 38 cases of infection by Babesia macropus, associated with a syndrome of anaemia and debility in hand-reared or free-ranging juvenile eastern grey kangaroos (Macropus giganteus) from coastal New South Wales and south-eastern Queensland between 1995 and 2013. Infection with B. macropus is recorded for the first time in agile wallabies (Macropus agilis) from far north Queensland. Animals in which B. macropus infection was considered to be the primary cause of morbidity had marked anaemia, lethargy and neurological signs, and often died. In these cases, parasitised erythrocytes were few or undetectable in peripheral blood samples but were sequestered in large numbers within small vessels of visceral organs, particularly in the kidney and brain, associated with distinctive clusters of extraerythrocytic organisms. Initial identification of this piroplasm in peripheral blood smears and in tissue impression smears and histological sections was confirmed using transmission electron microscopy and molecular analysis. Samples of kidney, brain or blood were tested using PCR and DNA sequencing of the 18S ribosomal RNA and heat shock protein 70 gene using primers specific for piroplasms. The piroplasm detected in these samples had 100% sequence identity in the 18S rRNA region with the recently described Babesia macropus in two eastern grey kangaroos from New South Wales and Queensland, and a high degree of similarity to an unnamed Babesia sp. recently detected in three woylies (Bettongia penicillata ogilbyi) in Western Australia. PMID:26106576

  8. Technical note: Differences in the diurnal pattern of soil respiration under adjacent Miscanthus × giganteus and barley crops reveal potential flaws in accepted sampling strategies

    NASA Astrophysics Data System (ADS)

    Ben Keane, J.; Ineson, Phil

    2017-03-01

    For convenience, measurements used to compare soil respiration (Rs) from different land uses, crops or management practices are often made between 09:00 and 16:00 UTC, convenience which is justified by an implicit assumption that Rs is largely controlled by temperature. Three months of continuous data presented here show distinctly different diurnal patterns of Rs between barley (Hordeum vulgare) and Miscanthus × giganteus (Miscanthus) grown on adjacent fields. Maximum Rs in barley occurred during the afternoon and correlated with soil temperature, whereas in Miscanthus after an initial early evening decline, Rs increased above the daily average during the night and in July maximum daily rates of Rs were seen at 22:00 and was significantly correlated with earlier levels of solar radiation, probably due to delays in translocation of recent photosynthate. Since the time of the daily mean Rs in Miscanthus occurred when Rs in the barley was 40 % greater than the daily mean, it is vital to select appropriate times to measure Rs especially if only single daily measurements are to be made.

  9. Potential of the beneficial fungus Trichoderma to enhance ecosystem-service provision in the biofuel grass Miscanthus x giganteus in agriculture

    PubMed Central

    Chirino-Valle, Ivan; Kandula, Diwakar; Littlejohn, Chris; Hill, Robert; Walker, Mark; Shields, Morgan; Cummings, Nicholas; Hettiarachchi, Dilani; Wratten, Stephen

    2016-01-01

    The sterile hybrid grass Miscanthus x giganteus (Mxg) can produce more than 30 t dry matter/ha/year. This biomass has a range of uses, including animal bedding and a source of heating fuel. The grass provides a wide range of other ecosystem services (ES), including shelter for crops and livestock, a refuge for beneficial arthropods, reptiles and earthworms and is an ideal cellulosic feedstock for liquid biofuels such as renewable (drop-in) diesel. In this study, the effects of different strains of the beneficial fungus Trichoderma on above- and below-ground biomass of Mxg were evaluated in glasshouse and field experiments, the latter on a commercial dairy farm over two years. Other ES benefits of Trichoderma measured in this study included enhanced leaf chlorophyll content as well as increased digestibility of the dried material for livestock. This study shows, for the first time for a biofuel feedstock plant, how Trichoderma can enhance productivity of such plants and complements other recent work on the wide-ranging provision of ES by this plant species. PMID:27117716

  10. Serologic-based investigation of leptospirosis in a population of free-ranging eastern grey kangaroos (Macropus giganteus) indicating the presence of Leptospira weilii serovar Topaz.

    PubMed

    Roberts, Michael W; Smythe, Lee; Dohnt, Michael; Symonds, Meegan; Slack, Andrew

    2010-04-01

    Eastern grey kangaroos (Macropus giganteus) are one of the most abundant large macropodids sharing the landscape with humans. Despite this, little is known about the prevalence of Leptospira carriage within this species and the role that they may partake in the transmission of this disease in Australia. The sera of 87 free-ranging eastern grey kangaroos, captured in the Warragamba Catchment Area, Sydney, Australia, from June 2004 to November 2006, were screened against a reference panel of 22 Leptospira serovars using the microscopic agglutination test (MAT). Leptospiral antibodies were detected in 47% (41 of 87) of serum samples collected. Leptospira weilii Topaz, a newly emergent serovar in Australia, was detected in all seropositive kangaroos (41 of 41; 100%). The sex and tail-fat body condition index of kangaroos appeared to have no significant effect on the exposure to the disease. This serologic-based study is the first reported for L. weilii serovar Topaz in New South Wales, to our knowledge, having previously been isolated only in humans and two other animal species (bovine and long-nosed bandicoot [Perameles nasuta]) in Western Australia and Queensland. The potential role of eastern grey kangaroos in the maintenance and zoonotic spread of the disease to livestock and humans is discussed.

  11. Army Acquisition Lessons Learned

    DTIC Science & Technology

    2014-10-01

    analysis on the lessons learned. Acquisition Lessons Learned Portal (ALLP) and Lessons Learned Collection CAALL has established the ALLP as the...PEOs) and their project offices, as well as the broader acquisition community. The primary function of the portal is to allow easy input and retrieval...download- able form that can be completed offline and then uploaded to the portal . This allows the form to be filled out and distrib- uted through

  12. Sperm competition and the evolution of precopulatory weapons: Testis size and amplexus position, but not arm strength, affect fertilization success in a chorusing frog.

    PubMed

    Buzatto, Bruno A; Thyer, Evan M; Roberts, J Dale; Simmons, Leigh W

    2017-02-01

    Trade-offs between pre- and postcopulatory traits influence their evolution, and male expenditure on such traits is predicted to depend on the number of competitors, the benefits from investing in weapons, and the risk and intensity of sperm competition. Males of the chorusing frog Crinia georgiana use their arms as weapons in contest competition. Previously, we showed that increased numbers of rivals elevated the risk and intensity of sperm competition due to multimale amplexus, and caused a reversal in the direction of precopulatory selection on arm girth. Here, we focused on the factors affecting postcopulatory fertilization success during group spawning, using paternity data from natural choruses. Competitive fertilization success depended on the time spent amplexed and amplexus position. Relative testes size but not arm girth, contributed to fertilization success, but the effect of testes size depended on amplexus position. Our findings offer within species empirical support for recent sperm competition models that incorporate precopulatory male-male competition, and show why an understanding of the evolution of animal weapons requires a consideration of both pre- and postcopulatory episodes of sexual selection.

  13. Fish Facts. Lesson Plan.

    ERIC Educational Resources Information Center

    Chan, Mike

    This lesson plan is designed for a 50-minute class to teach extension home economists and homemakers about buying, storing, and using fish. The lesson plan contains references, a list of equipment needed, objectives, and the presentation. The presentation consists of an outline of instruction coordinated with methods of instruction and aids and…

  14. "Frankenstein." [Lesson Plan].

    ERIC Educational Resources Information Center

    Simon, Melanie

    Based on Mary Shelley's novel "Frankenstein," this lesson plan presents activities designed to help students understand that active readers interpret a novel (its characters, plot, setting, and theme) in different ways; and the great literature can be and has been adapted in many ways over time. The main activity of the lesson involves students…

  15. Jamestown Changes [Lesson Plan].

    ERIC Educational Resources Information Center

    2000

    In this lesson, students study census data showing the names and occupations of early settlers of the English settlement at Jamestown, Virginia, to discern how life changed in the Jamestown settlement in the first few years after it was founded. Learning objectives of the lesson plan are: (1) to gain experience gathering information from primary…

  16. Beginners Lessons for Adults

    ERIC Educational Resources Information Center

    Dunlop, Ian

    1974-01-01

    For the teaching of English beyond the elementary level, a lesson plan for beginners is presented and discussed. In the center of the proposed lesson plan are, among other things, cooperative exercises ("individual pupils asking and answering questions of each other"), as well as exercises in vocabulary, grammar and pronunciation (voiced/voiceless…

  17. Ohio Agriscience Lesson Plans.

    ERIC Educational Resources Information Center

    Sommers, Robert D., II, Comp.; Waidelich, William D., Comp.

    This document, which is intended for Ohio agriculture teachers, contains lesson plans for an eight-unit competency-based course in agriscience. Each lesson plan contains some or all of the following items: (1) unit title; (2) competency/terminal performance objective; (3) competency builders/pupil performance objectives; (4) list of applied…

  18. Collaborative Lesson Plans.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum and Resource Center.

    This collection consists of 41 collaborative lesson plans developed by 99 Virginia teachers at 18 primarily High Schools that Work (HSTW) and tech prep sites. It is divided into three sections: career connection, community connection, and consumer connection. Two types of lesson descriptions which support HSTW key practices, and Virginia's Tech…

  19. Automatic Dance Lesson Generation

    ERIC Educational Resources Information Center

    Yang, Yang; Leung, H.; Yue, Lihua; Deng, LiQun

    2012-01-01

    In this paper, an automatic lesson generation system is presented which is suitable in a learning-by-mimicking scenario where the learning objects can be represented as multiattribute time series data. The dance is used as an example in this paper to illustrate the idea. Given a dance motion sequence as the input, the proposed lesson generation…

  20. Mathematics Lessons without ...

    ERIC Educational Resources Information Center

    Cross, Kath; Hibbs, John

    2006-01-01

    In the Association of Teachers of Mathematics (ATM) Easter conference, 2006, the authors presented a list of important aspects of mathematics lessons, recommended for students to have a positive attitude to mathematics and for teachers to acquire effective teaching. The following are discussed in detail: (1) Mathematics lessons without good…

  1. "Walden". [Lesson Plan].

    ERIC Educational Resources Information Center

    Surber, Gretchen C.

    Based on Henry David Thoreau's book "Walden," this lesson plan presents activities designed to help students understand that acquisitiveness and simplicity can be opposing life philosophies; and that both philosophies have had notable adherents. The main activity of the lesson involves students researching historical characters (including Thoreau)…

  2. Don Quixote. [Lesson Plan].

    ERIC Educational Resources Information Center

    Rooks, Kristen

    Based on Miguel de Cervantes' novel "Don Quixote," this lesson plan presents activities designed to help students understand that Quixote's misperceptions are understandable; writers often describe one object to sound as if it were something else; and metaphors help readers see with new eyes. The main activity of the lesson involves students…

  3. Ben Franklin. [Lesson Plan].

    ERIC Educational Resources Information Center

    Discovery Communications, Inc., Bethesda, MD.

    Based on Benjamin Franklin's "Poor Richard's Almanac," this lesson plan presents activities designed to help students understand that Ben Franklin is known, among other things, for his wit and wisdom; that Franklin published an almanac for 25 years; and he scattered aphorisms throughout the almanac. The main activity in the lesson is for students…

  4. Lessons of the Narragansetts.

    ERIC Educational Resources Information Center

    Narraganset Tribal Education Project, Inc., Charleston, RI.

    The curriculum guide presents lesson plans and suggested activities for a six-week mini course for secondary students on the culture and history of the Narragansett Indians. It is part of the Narragansett Tribe Ethnic Heritage Program. An outline of the general format and content suggests a time allotment for each of the 12 lessons. The lessons…

  5. A Lesson in Tolerance

    ERIC Educational Resources Information Center

    Johnt, Marlene

    2004-01-01

    This article describes one classroom's experience integrating a three-part lesson that focused on tolerance. In the lesson, students examined works by American folk-art painter Edward Hicks, researched quotes about tolerance in society, and applied calligraphy skills to an original composition.

  6. Gulliver's Travels. [Lesson Plan].

    ERIC Educational Resources Information Center

    Rooks, Kirsten; McLean, Mary

    Based on Jonathan Swift's novel "Gulliver's Travels," this lesson plan presents activities designed to help students understand that Swift comments on undesirable outcomes of advances in science; and other authors have also warned against abuse of science. The main activity of the lesson involves students developing a poster illustrating views of…

  7. Lesson Study: Beyond Coaching

    ERIC Educational Resources Information Center

    Lewis, Catherine; Perry, Rebecca; Foster, David; Hurd, Jacqueline; Fisher, Linda

    2011-01-01

    The authors assert that lesson study--a collaborative, teacher-led approach to learning from practice--offers a deeper, broader, more sustainable method of improving teacher practice than one-on-one coaching does. In lesson study, teachers and coaches of all levels of experience can work together, each bringing his or her own professional…

  8. Mathematics Lessons without ...

    ERIC Educational Resources Information Center

    Cross, Kath; Hibbs, John

    2006-01-01

    In the Association of Teachers of Mathematics (ATM) Easter conference, 2006, the authors presented a list of important aspects of mathematics lessons, recommended for students to have a positive attitude to mathematics and for teachers to acquire effective teaching. The following are discussed in detail: (1) Mathematics lessons without good…

  9. Soybean Production Lesson Plan.

    ERIC Educational Resources Information Center

    Carlson, Keith R.

    These lesson plans for teaching soybean production in a secondary or postsecondary vocational agriculture class are organized in nine units and cover the following topics: raising soybeans, optimum tillage, fertilizer and lime, seed selection, pest management, planting, troubleshooting, double cropping, and harvesting. Each lesson plan contains…

  10. Lesson Study: Beyond Coaching

    ERIC Educational Resources Information Center

    Lewis, Catherine; Perry, Rebecca; Foster, David; Hurd, Jacqueline; Fisher, Linda

    2011-01-01

    The authors assert that lesson study--a collaborative, teacher-led approach to learning from practice--offers a deeper, broader, more sustainable method of improving teacher practice than one-on-one coaching does. In lesson study, teachers and coaches of all levels of experience can work together, each bringing his or her own professional…

  11. Mini Lessons from FDA.

    ERIC Educational Resources Information Center

    Food and Drug Administration (DHEW), Washington, DC.

    Eight self-contained lessons present information about topics of current interest in the Food and Drug Administration. Multidisciplinary in nature, the lessons can be integrated into ongoing activities in elementary or secondary level reading, math, language arts, social studies, science, art, health, consumer education, and home economics. The…

  12. Fish Facts. Lesson Plan.

    ERIC Educational Resources Information Center

    Chan, Mike

    This lesson plan is designed for a 50-minute class to teach extension home economists and homemakers about buying, storing, and using fish. The lesson plan contains references, a list of equipment needed, objectives, and the presentation. The presentation consists of an outline of instruction coordinated with methods of instruction and aids and…

  13. Soybean Production Lesson Plan.

    ERIC Educational Resources Information Center

    Carlson, Keith R.

    These lesson plans for teaching soybean production in a secondary or postsecondary vocational agriculture class are organized in nine units and cover the following topics: raising soybeans, optimum tillage, fertilizer and lime, seed selection, pest management, planting, troubleshooting, double cropping, and harvesting. Each lesson plan contains…

  14. Great Expectations. [Lesson Plan].

    ERIC Educational Resources Information Center

    Devine, Kelley

    Based on Charles Dickens' novel "Great Expectations," this lesson plan presents activities designed to help students understand the differences between totalitarianism and democracy; and a that a writer of a story considers theme, plot, characters, setting, and point of view. The main activity of the lesson involves students working in groups to…

  15. Low growth temperatures modify the efficiency of light use by photosystem II for CO2 assimilation in leaves of two chilling-tolerant C4 species, Cyperus longus L. and Miscanthus x giganteus.

    PubMed

    Farage, Peter K; Blowers, David; Long, Stephen P; Baker, Neil R

    2006-04-01

    Two C4 plants, Miscanthus x giganteus and Cyperus longus L., were grown at suboptimal growth temperatures and the relationships between the quantum efficiencies of photosynthetic electron transport through photosystem II (PSII) (PSII operating efficiency; Fq'/Fm') and CO2 assimilation (phiCO2) in leaves were examined. When M. x giganteus was grown at 10 degrees C, the ratio of the PSII operating efficiency to phiCO2 increased relative to that found in leaves grown at 14 and 25 degrees C. Similar increases in the Fq'/Fm': phiCO2 occurred in the leaves of two C. longus ecotypes when the plants were grown at 17 degrees C, compared to 25 degrees C. These elevations of Fq'/Fm': phiCO2 at low growth temperatures were not attributable to the development of anthocyanins, as has been suggested for maize, and were indicative of the operation of an alternative sink to CO2 assimilation for photosynthetic reducing equivalents, possibly oxygen reduction via a Mehler reaction, which would act as a mechanism for protection of PSII from photoinactivation and damage. Furthermore, in M. x giganteus grown at 10 degrees C, further protection of PSII was effected by a 20-fold increase in zeaxanthin content in dark-adapted leaves, which was associated with much higher levels of non-photochemical quenching of excitation energy, compared to that observed in leaves grown at 14 and 25 degrees C. These differences may explain the long growing season and remarkable productivity of this C4 plant in cool climates, even in comparison to other C4 species such as C. longus, which occur naturally in such climates.

  16. Final Report DE-SC0006634. Quantifying phenotypic and genetic diversity of Miscanthus sinensis as a resource for knowledge-based improvement of M. ×giganteus (M. sinensis × M. sacchariflorus)

    SciTech Connect

    Sacks, Erik

    2016-02-08

    Miscanthus is especially attractive as a bioenergy crop for temperate environments because it produces high yields, needs few inputs, and grows well during the cool weather of early spring and late fall when few warm-season grasses can. However, Miscanthus feedstock production for the emerging U.S. bioenergy industry and for existing demand in Europe is based on a single sterile, vegetatively propagated variety of M. ×giganteus. M. ×giganteus is an interspecific hybrid of the parental species M. sinensis and M. sacchariflorus. Prior to the current study, little information existed about the genetic diversity and breeding potential of either M. ×giganteus parental species. In the current project, we studied more than 600 accessions of M. sinensis from throughout its native range in China, Japan, and Korea, in addition to ornamental cultivars and U.S. naturalized populations. Using thousands of DNA markers, we identified seven geographically distinct genetic groups of M. sinensis. Notably, we found that the ornamental cultivars and U.S. naturalized populations were derived from only a subset of the Southern Japan group, indicating that our study greatly increased the genetic diversity available for breeding new biomass cultivars. Additionally, this new understanding of M. sinensis population structure could be used to predict which crosses may produce progeny with the greatest hybrid vigor. Replicated field trials were also established at multiple locations in North America and Asia. Data on traits of importance for biomass productivity, such as flowering time, yield and height, were taken. Analyses of the phenotypic data from the field trials along with the DNA markers allowed us to identify many marker-trait associations. These results will enable marker-assisted breeding, which will allow selection at the seedling stage rather than waiting two to three years to obtain phenotypic data. Thus, this study is expected to greatly increase the efficiency of breeding

  17. How Does a Lesson Plan?

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Curriculum and Instruction.

    This manual for secondary school teachers offers sample lesson plans that may be used to guide and stimulate experimentation and development of creative instructional units. Lesson plan components are defined, and various types of lessons and their significant characteristics are identified. These characteristic types of lessons are illustrated,…

  18. Phylogeny in Defining Model Plants for Lignocellulosic Ethanol Production: A Comparative Study of Brachypodium distachyon, Wheat, Maize, and Miscanthus x giganteus Leaf and Stem Biomass

    PubMed Central

    Meineke, Till; Manisseri, Chithra; Voigt, Christian A.

    2014-01-01

    The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108–117 mg ethanol·g−1 dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type. PMID:25133818

  19. Variation in chilling tolerance for photosynthesis and leaf extension growth among genotypes related to the C4 grass Miscanthus ×giganteus.

    PubMed

    Głowacka, Katarzyna; Adhikari, Shivani; Peng, Junhua; Gifford, Justin; Juvik, John A; Long, Stephen P; Sacks, Erik J

    2014-10-01

    The goal of this study was to identify cold-tolerant genotypes within two species of Miscanthus related to the exceptionally chilling-tolerant C4 biomass crop accession: M. ×giganteus 'Illinois' (Mxg) as well as in other Mxg genotypes. The ratio of leaf elongation at 10 °C/5 °C to that at 25 °C/25 °C was used to identify initially the 13 most promising Miscanthus genotypes out of 51 studied. Net leaf CO2 uptake (A sat) and the maximum operating efficiency of photosystem II (ФPSII) were measured in warm conditions (25 °C/20 °C), and then during and following a chilling treatment of 10 °C/5 °C for 11 d. Accessions of M. sacchariflorus (Msa) showed the smallest decline in leaf elongation on transfer to chilling conditions and did not differ significantly from Mxg, indicating greater chilling tolerance than diploid M. sinensis (Msi). Msa also showed the smallest reductions in A sat and ФPSII, and greater chilling-tolerant photosynthesis than Msi, and three other forms of Mxg, including new triploid accessions and a hexaploid Mxg 'Illinois'. Tetraploid Msa 'PF30153' collected in Gifu Prefecture in Honshu, Japan did not differ significantly from Mxg 'Illinois' in leaf elongation and photosynthesis at low temperature, but was significantly superior to all other forms of Mxg tested. The results suggested that the exceptional chilling tolerance of Mxg 'Illinois' cannot be explained simply by the hybrid vigour of this intraspecific allotriploid. Selection of chilling-tolerant accessions from both of Mxg's parental species, Msi and Msa, would be advisable for breeding new highly chilling-tolerant Mxg genotypes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. Hybridization and back-crossing in giant petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a summary of hybridization in seabirds.

    PubMed

    Brown, Ruth M; Techow, N M S Mareile; Wood, Andrew G; Phillips, Richard A

    2015-01-01

    Hybridization in natural populations provides an opportunity to study the evolutionary processes that shape divergence and genetic isolation of species. The emergence of pre-mating barriers is often the precursor to complete reproductive isolation. However, in recently diverged species, pre-mating barriers may be incomplete, leading to hybridization between seemingly distinct taxa. Here we report results of a long-term study at Bird Island, South Georgia, of the extent of hybridization, mate fidelity, timing of breeding and breeding success in mixed and conspecific pairs of the sibling species, Macronectes halli (northern giant petrel) and M. giganteus (southern giant petrel). The proportion of mixed-species pairs varied annually from 0.4-2.4% (mean of 1.5%), and showed no linear trend with time. Mean laying date in mixed-species pairs tended to be later than in northern giant petrel, and always earlier than in southern giant petrel pairs, and their breeding success (15.6%) was lower than that of conspecific pairs. By comparison, mixed-species pairs at both Marion and Macquarie islands always failed before hatching. Histories of birds in mixed-species pairs at Bird Island were variable; some bred previously or subsequently with a conspecific partner, others subsequently with a different allospecific partner, and some mixed-species pairs remained together for multiple seasons. We also report the first verified back-crossing of a hybrid giant petrel with a female northern giant petrel. We discuss the potential causes and evolutionary consequences of hybridization and back-crossing in giant petrels and summarize the incidence of back-crossing in other seabird species.

  1. Hybridization and Back-Crossing in Giant Petrels (Macronectes giganteus and M. halli) at Bird Island, South Georgia, and a Summary of Hybridization in Seabirds

    PubMed Central

    Brown, Ruth M.; Techow, N. M. S. Mareile; Wood, Andrew G.; Phillips, Richard A.

    2015-01-01

    Hybridization in natural populations provides an opportunity to study the evolutionary processes that shape divergence and genetic isolation of species. The emergence of pre-mating barriers is often the precursor to complete reproductive isolation. However, in recently diverged species, pre-mating barriers may be incomplete, leading to hybridization between seemingly distinct taxa. Here we report results of a long-term study at Bird Island, South Georgia, of the extent of hybridization, mate fidelity, timing of breeding and breeding success in mixed and conspecific pairs of the sibling species, Macronectes halli (northern giant petrel) and M. giganteus (southern giant petrel). The proportion of mixed-species pairs varied annually from 0.4–2.4% (mean of 1.5%), and showed no linear trend with time. Mean laying date in mixed-species pairs tended to be later than in northern giant petrel, and always earlier than in southern giant petrel pairs, and their breeding success (15.6%) was lower than that of conspecific pairs. By comparison, mixed-species pairs at both Marion and Macquarie islands always failed before hatching. Histories of birds in mixed-species pairs at Bird Island were variable; some bred previously or subsequently with a conspecific partner, others subsequently with a different allospecific partner, and some mixed-species pairs remained together for multiple seasons. We also report the first verified back-crossing of a hybrid giant petrel with a female northern giant petrel. We discuss the potential causes and evolutionary consequences of hybridization and back-crossing in giant petrels and summarize the incidence of back-crossing in other seabird species. PMID:25815478

  2. Genomic and small RNA sequencing of Miscanthus × giganteus shows the utility of sorghum as a reference genome sequence for Andropogoneae grasses

    PubMed Central

    2010-01-01

    Background Miscanthus × giganteus (Mxg) is a perennial grass that produces superior biomass yields in temperate environments. The essentially uncharacterized triploid genome (3n = 57, x = 19) of Mxg is likely critical for the rapid growth of this vegetatively propagated interspecific hybrid. Results A survey of the complex Mxg genome was conducted using 454 pyrosequencing of genomic DNA and Illumina sequencing-by-synthesis of small RNA. We found that the coding fraction of the Mxg genome has a high level of sequence identity to that of other grasses. Highly repetitive sequences representing the great majority of the Mxg genome were predicted using non-cognate assembly for de novo repeat detection. Twelve abundant families of repeat were observed, with those related to either transposons or centromeric repeats likely to comprise over 95% of the genome. Comparisons of abundant repeat sequences to a small RNA survey of three Mxg organs (leaf, rhizome, inflorescence) revealed that the majority of observed 24-nucleotide small RNAs are derived from these repetitive sequences. We show that high-copy-number repeats match more of the small RNA, even when the amount of the repeat sequence in the genome is accounted for. Conclusions We show that major repeats are present within the triploid Mxg genome and are actively producing small RNAs. We also confirm the hypothesized origins of Mxg, and suggest that while the repeat content of Mxg differs from sorghum, the sorghum genome is likely to be of utility in the assembly of a gene-space sequence of Mxg. PMID:20128909

  3. Effect of C/N ratio and microelements on nutrient dynamics and cell morphology in submerged fermentation of Aspergillus giganteus MTCC 8408 using Taguchi DOE.

    PubMed

    Dutta, Debashis; Das, Mira Debnath

    2017-05-01

    This paper is concerned with the effect of individual Na(+), K(+), Mg(2+) and Ca(2+) ions upon the nutrient dynamics and cell morphology during submerged fermentation of Aspergillus giganteus MTCC 8408 in a medium containing ample soluble starch, corn steep liquor and proteose peptone supply. Nutrient dynamics was elucidated using Taguchi's DOE (design of experiment) L8 orthogonal array (OA) with carbon, nitrogen and four most influensive microelements at their assigned ratio namely; K(+)/Ca(2+) and Mg(2+)/Na(+). Scanning electron microscopy (SEM) was used to correlate the effect of selected factors on morphological changes and nutrient dynamics during submerged fermentation. At higher K(+)/Ca(2+) ratio 4.78:1; the maximum growth was figured out in terms of dry weight, while the inhibition of dry weight production was observed at higher Mg(2+)/Na(+) ratio 0.94:1 with enhanced intracellular afp production. At lower C/N ratio 27.4:1; filamentous form of growth was maintained with the hyphae being scarcely branched without bulbous cells. Membrane perturbation due to the induction of intracellular oxidative stress was noticed at higher C/N ration. Taguchi DOE resulted in afp yield per substrate utilized, Y p/s of 1.08 mg g(-1) soluble starch utilized with gram dry cell weight (gdcw) of 23.9 g L(-1) while afp yield per biomass utilized resulted, Y p/x of 1.12 mg afp gdcw(-1) L(-1) and biomass yield per substrate utilized, Y x/s of 1.195 gdcw g(-1) L(-1). The present study revealed an opportunity to develop a cost effective methods for cell propagation so as to yield effective inoculum levels towards mass production and formulation studies.

  4. Phylogeny in defining model plants for lignocellulosic ethanol production: a comparative study of Brachypodium distachyon, wheat, maize, and Miscanthus x giganteus leaf and stem biomass.

    PubMed

    Meineke, Till; Manisseri, Chithra; Voigt, Christian A

    2014-01-01

    The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108-117 mg ethanol·g(-1) dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type.

  5. Sharing Lessons Learned

    SciTech Connect

    Mohler, Bryan L.

    2004-09-01

    Workplace safety is inextricably tied to the culture – the leadership, management and organization – of the entire company. Nor is a safety lesson fundamentally different from any other business lesson. With these points in mind, Pacific Northwest National Laboratory recast its lessons learned program in 2000. The laboratory retained elements of a traditional lessons learned program, such as tracking and trending safety metrics, and added a best practices element to increase staff involvement in creating a safer, healthier work environment. Today, the Lessons Learned/Best Practices program offers the latest business thinking summarized from current external publications and shares better ways PNNL staff have discovered for doing things. According to PNNL strategic planning director Marilyn Quadrel, the goal is to sharpen the business acumen, project management ability and leadership skills of all staff and to capture the benefits of practices that emerge from lessons learned. A key tool in the PNNL effort to accelerate learning from past mistakes is one that can be easily implemented by other firms and tailored to their specific needs. It is the weekly placement of Lessons Learned/Best Practices articles in the lab’s internal electronic newsletter. The program is equally applicable in highly regulated environments, such as the national laboratories, and in enterprises that may have fewer external requirements imposed on their operations. And it is cost effective, using less than the equivalent of one fulltime person to administer.

  6. Impact of event-specific chorus wave realization for modeling the October 8-9, 2012, event using the LANL DREAM3D diffusion code

    NASA Astrophysics Data System (ADS)

    Cunningham, G.; Tu, W.; Chen, Y.; Reeves, G. D.; Henderson, M. G.; Baker, D. N.; Blake, J. B.; Spence, H.

    2013-12-01

    During the interval October 8-9, 2012, the phase-space density (PSD) of high-energy electrons exhibited a dropout preceding an intense enhancement observed by the MagEIS and REPT instruments aboard the Van Allen Probes. The evolution of the PSD suggests heating by chorus waves, which were observed to have high intensities at the time of the enhancement [1]. Although intense chorus waves were also observed during the first Dst dip on October 8, no PSD enhancement was observed at this time. We demonstrate a quantitative reproduction of the entire event that makes use of three recent modifications to the LANL DREAM3D diffusion code: 1) incorporation of a time-dependent, low-energy, boundary condition from the MagEIS instrument, 2) use of a time-dependent estimate of the chorus wave intensity derived from observations of POES low-energy electron precipitation, and 3) use of an estimate of the last closed drift shell, beyond which electrons are assumed to have a lifetime that is proportional to their drift period around earth. The key features of the event are quantitatively reproduced by the simulation, including the dropout on October 8, and a rapid increase in PSD early on October 9, with a peak near L*=4.2. The DREAM3D code predicts the dropout on October 8 because this feature is dominated by magnetospheric compression and outward radial diffusion-the L* of the last closed drift-shell reaches a minimum value of 5.33 at 1026 UT on October 8. We find that a ';statistical' wave model based on historical CRRES measurements binned in AE* does not reproduce the enhancement because the peak wave amplitudes are only a few 10's of pT, whereas an ';event-specific' model reproduces both the magnitude and timing of the enhancement very well, a s shown in the Figure, because the peak wave amplitudes are 10x higher. [1] 'Electron Acceleration in the Heart of the Van Allen Radiation Belts', G. D. Reeves et al., Science 1237743, Published online 25 July 2013 [DOI:10.1126/science

  7. Lessons on the Cold War. Lesson Plan.

    ERIC Educational Resources Information Center

    Cunningham, Susan J.

    1994-01-01

    Contends that the end of the Cold War requires teachers to change their teaching methods and content. Presents six lessons, most with three individual student activities, that trace the Cold War from the pre-World War I era through the end of the Vietnam War. (CFR)

  8. Music lessons enhance IQ.

    PubMed

    Schellenberg, E Glenn

    2004-08-01

    The idea that music makes you smarter has received considerable attention from scholars and the media. The present report is the first to test this hypothesis directly with random assignment of a large sample of children (N = 144) to two different types of music lessons (keyboard or voice) or to control groups that received drama lessons or no lessons. IQ was measured before and after the lessons. Compared with children in the control groups, children in the music groups exhibited greater increases in full-scale IQ. The effect was relatively small, but it generalized across IQ subtests, index scores, and a standardized measure of academic achievement. Unexpectedly, children in the drama group exhibited substantial pre- to post-test improvements in adaptive social behavior that were not evident in the music groups.

  9. Lessons for Introductory Chemistry

    NASA Astrophysics Data System (ADS)

    Martin, John S.; Blackburn, Edward V.

    2000-07-01

    These twelve lessons, and an introductory lesson, are tutorials in basic topics of introductory chemistry. They are suitable for school use, individual study, or distance learning. They are particularly valuable as review material for students in more advanced courses who may have been away from the subject for some time. They contain a great variety of problems and exercises driven by random-number generators, so that the same problem never repeats exactly. The lessons are, for the most part, Socratic dialogues in which the student is required to answer questions and perform simulated experiments in order to discover chemical principles. They are organized in an intuitive chapter and page structure. One may move readily around each lesson. There are many on-screen facilities such as help, data tables, and a calculator.

  10. Lesson 6: Registration

    EPA Pesticide Factsheets

    Lesson 6 provides checklist items 1 through 4 are grouped under the Registration Process, where users establish their accounts in the system. This process typically requires users to provide information about them.

  11. Spotting a Science Lesson.

    ERIC Educational Resources Information Center

    Manch, Raimonde

    1989-01-01

    A hands-on science lesson which allows young students to apply stains in the classroom and then try to remove them is presented. Included are a list of materials, procedures, and a discussion of probable results. (CW)

  12. Can the exceptional chilling tolerance of C4 photosynthesis found in Miscanthus × giganteus be exceeded? Screening of a novel Miscanthus Japanese germplasm collection.

    PubMed

    Głowacka, Katarzyna; Jørgensen, Uffe; Kjeldsen, Jens B; Kørup, Kirsten; Spitz, Idan; Sacks, Erik J; Long, Stephen P

    2015-05-01

    A clone of the hybrid perennial C4 grass Miscanthus × giganteus (Mxg) is known for achieving exceptionally high rates of leaf CO2 uptake during chilling. This is a requisite of success in the early spring, as is the ability of the leaves to survive occasional frosts. The aim of this study was to search for genotypes with greater potential than Mxg for photosynthesis and frost survival under these conditions. A total of 864 accessions representing 164 local populations of M. sacchariflorus (Msa), M. sinensis (Msi) and M. tinctorius (Mti) collected across Japan were studied. Accessions whose leaves survived a natural late frost in the field were screened for high maximum photosystem II efficiency (Fv/Fm) following chilling weather, as an indicator of their capacity for light-limited photosynthesis. Those showing the highest Fv/Fm were transferred to a high-light-controlled environment and maintained at chilling temperatures, where they were further screened for their capacities for high-light-limited and light-saturated leaf uptake of CO2 (ΦCO2,max and Asat, respectively). For the first time, relatives of Mxg with significantly superior capacities for photosynthesis at chilling temperatures were identified. Msa accession '73/2' developed leaves in the spring that survived night-time frost, and during growth under chilling maintained a statistically significant 79 % higher ΦCO2,max, as a measure of light-limited photosynthesis, and a 70 % higher Asat, as a measure of light-saturated photosynthesis. A second Msa accession, '73/3' also showed significantly higher rates of leaf uptake of CO2. As remarkable as Mxg has proved in its chilling tolerance of C4 photosynthesis, this study shows that there is still value and potential in searching for yet more superior tolerance. Msa accession '73/2' shows rates of light-limited and light-saturated photosynthesis at chilling temperatures that are comparable with those of the most cold-tolerant C3 species. This adds

  13. One Teacher, Two Lessons: The Lesson Study Process

    ERIC Educational Resources Information Center

    Robinson, Naomi; Leikin, Roza

    2012-01-01

    In this paper, we analyze 2 lessons by 1 teacher that took place during a lesson study (LS) cycle for a team of elementary mathematics teachers. We analyze the data on 2 levels: macro-level analysis, dealing with lesson structure and setting; and micro-level analysis, zooming in on mathematical tasks and the quality of whole-class discussion. We…

  14. Breathing Life into Engineering: A Lesson Study Life Science Lesson

    ERIC Educational Resources Information Center

    Lawrence, Maria; Yang, Li-Ling; Briggs, May; Hession, Alicia; Koussa, Anita; Wagoner, Lisa

    2016-01-01

    A fifth grade life science lesson was implemented through a lesson study approach in two fifth grade classrooms. The research lesson was designed by a team of four elementary school teachers with the goal of emphasizing engineering practices consistent with the "Next Generation Science Standards" (NGSS) (Achieve Inc. 2013). The fifth…

  15. Breathing Life into Engineering: A Lesson Study Life Science Lesson

    ERIC Educational Resources Information Center

    Lawrence, Maria; Yang, Li-Ling; Briggs, May; Hession, Alicia; Koussa, Anita; Wagoner, Lisa

    2016-01-01

    A fifth grade life science lesson was implemented through a lesson study approach in two fifth grade classrooms. The research lesson was designed by a team of four elementary school teachers with the goal of emphasizing engineering practices consistent with the "Next Generation Science Standards" (NGSS) (Achieve Inc. 2013). The fifth…

  16. COSS Lesson Creation Process

    NASA Technical Reports Server (NTRS)

    Harper, R. Stephen

    1999-01-01

    COSS (Crew On-Orbit System Support) is changing. Designed as computer based in-flight refresher training, it is getting good reviews and the demands on the product can be expected to increase. Last year, the lessons were written using Authorware, which had a number of limitations. The most important one was that the navigation and the layout functions were both in one package that was not easy to learn. The lesson creator had to be good at both programming and design. There were also a number of other problems, as detailed in my report last year. This year the COSS unit made the switch to embrace modularity. The navigation function is handled by a player that was custom-written using Delphi. The layout pages are now standard HTML files that can be created using any number of products. This new system gives new flexibility and unties the process from one product (and one company). The player can be re-written by a programmer without affecting the lesson pages. It is also now possible for anybody with a word-processor to make part of the HTML lesson pages and to use many of the new commercially available tools that are being designed for web pages. This summer I created a computer-based training (CBT) lesson on the IBM ThinkPad 760 ED and 760XD laptop computers that should fly on the International Space Station. I also examined the COSS system, the new player and the other new software products.

  17. Equity Lessons for Elementary School.

    ERIC Educational Resources Information Center

    Philadelphia School District, PA. Office of Curriculum and Instruction.

    Elementary students will develop an awareness of the many facets of sex-role stereotyping through these 10 lessons. The broad concept areas of the individual lessons correspond to the general areas of a basic elementary social studies program. Foci of the lessons are reflected in their titles: (1) Self-Realization: Feelings and Expressions; (2)…

  18. Developing Assessment through Lesson Study

    ERIC Educational Resources Information Center

    Fischman, Davida; Wasserman, Kelli

    2017-01-01

    Lesson study cultivates teachers' capacity for formative assessment by placing student thinking front and center throughout. Lesson study is a form of professional development in which a team of teachers determines a mathematical focus, collaboratively studies student thinking about the topic, designs a lesson about this content, implements the…

  19. Community College Biology Lesson Index.

    ERIC Educational Resources Information Center

    Manteuffel, Mary S., Comp.; Herrick, Kathie, Comp.

    This catalog contains lesson descriptions of the available biology lessons on PLATO IV, compiled to assist instructors in planning their curricula. Information is provided for 87 lessons in the following areas: introductory material on experimental tools and techniques; chemical basis of life; cellular structure and function; reproduction and…

  20. Fire Officer I Lesson Plans.

    ERIC Educational Resources Information Center

    Pribyl, Paul F.

    Lesson plans are provided for the Fire Officer I course. Material for each lesson is presented in this format: course title, lesson title, equipment required, training aids needed, and a content outline which details teaching points and related instructor references. These references, or suggested readings, are listed at the conclusion of each…

  1. Lessons for Teaching Art Criticism.

    ERIC Educational Resources Information Center

    Barrett, Terry, Ed.; Clark, Gilbert, Ed.

    This collection of lessons is meant to be a practical guide to help teachers engage children in art criticism. The lessons generally follow a similar format. Most suggest an age group but may be modified for use with younger or older students. Several authors suggest variations and extensions for lessons that include studio activities. A broad…

  2. Lesson Study with Preservice Teachers

    ERIC Educational Resources Information Center

    McMahon, Mary T.; Hines, Ellen

    2008-01-01

    Lesson study is a teacher-directed program for improving instruction. It focuses on improving students' learning by systematically refining the lessons used for instruction. In this article, the authors describe the use of lesson study with preservice secondary mathematics teachers to encourage collaborative reflection and professional…

  3. Lesson Planning the Kodaly Way.

    ERIC Educational Resources Information Center

    Boshkoff, Ruth

    1991-01-01

    Discusses the contribution of Zoltan Kodaly to music lesson planning. Emphasizes preparation, presentation, and practice as the three important strategies in teaching concepts and skills to be included in a lesson plan. Includes a sample lesson plan covering a semester and advice on choosing song material. (DK)

  4. Lessons learned bulletin. Number 2

    SciTech Connect

    Not Available

    1994-05-01

    During the past four years, the Department of Energy -- Savannah River Operations Office and the Westinghouse Savannah River Company (WSRC) Environmental Restoration (ER) Program completed various activities ranging from waste site investigations to closure and post closure projects. Critiques for lessons learned regarding project activities are performed at the completion of each project milestone, and this critique interval allows for frequent recognition of lessons learned. In addition to project related lessons learned, ER also performs lessons learned critiques. T`he Savannah River Site (SRS) also obtains lessons learned information from general industry, commercial nuclear industry, naval nuclear programs, and other DOE sites within the complex. Procedures are approved to administer the lessons learned program, and a database is available to catalog applicable lessons learned regarding environmental remediation, restoration, and administrative activities. ER will continue to use this database as a source of information available to SRS personnel.

  5. The Coordination of C4 Photosynthesis and the CO2-Concentrating Mechanism in Maize and Miscanthus × giganteus in Response to Transient Changes in Light Quality1[W][OPEN

    PubMed Central

    Sun, Wei; Ubierna, Nerea; Ma, Jian-Ying; Walker, Berkley J.; Kramer, David M.; Cousins, Asaph B.

    2014-01-01

    Unequal absorption of photons between photosystems I and II, and between bundle-sheath and mesophyll cells, are likely to affect the efficiency of the CO2-concentrating mechanism in C4 plants. Under steady-state conditions, it is expected that the biochemical distribution of energy (ATP and NADPH) and photosynthetic metabolite concentrations will adjust to maintain the efficiency of C4 photosynthesis through the coordination of the C3 (Calvin-Benson-Bassham) and C4 (CO2 pump) cycles. However, under transient conditions, changes in light quality will likely alter the coordination of the C3 and C4 cycles, influencing rates of CO2 assimilation and decreasing the efficiency of the CO2-concentrating mechanism. To test these hypotheses, we measured leaf gas exchange, leaf discrimination, chlorophyll fluorescence, electrochromatic shift, photosynthetic metabolite pools, and chloroplast movement in maize (Zea mays) and Miscanthus × giganteus following transitional changes in light quality. In both species, the rate of net CO2 assimilation responded quickly to changes in light treatments, with lower rates of net CO2 assimilation under blue light compared with red, green, and blue light, red light, and green light. Under steady state, the efficiency of CO2-concentrating mechanisms was similar; however, transient changes affected the coordination of C3 and C4 cycles in M. giganteus but to a lesser extent in maize. The species differences in the ability to coordinate the activities of C3 and C4 cycles appear to be related to differences in the response of cyclic electron flux around photosystem I and potentially chloroplast rearrangement in response to changes in light quality. PMID:24488966

  6. The Effects of Lesson Study on Classroom Observations and Perceptions of Lesson Effectiveness

    ERIC Educational Resources Information Center

    Myers, Julia

    2012-01-01

    This study examined the effects of lesson study on participants' classroom observations and perceptions of lesson effectiveness, by investigating the focus of their observations during a mathematics lesson and their ratings of the lesson's effectiveness, both preceding and subsequent to the lesson study experience. Prior to the lesson study,…

  7. Mississippi River. [Lesson Plan].

    ERIC Educational Resources Information Center

    Buchberg, Wendy

    Based on novels and books about the Mississippi River, this lesson plan presents activities designed to help students understand that the Mississippi River has made its mark on America's geography, commerce, and literature; and that booktalks provide a summary, explains what kind of reader the book will appeal to, and may also contain a oral…

  8. Lessons from the Heartland

    ERIC Educational Resources Information Center

    Miner, Barbara

    2013-01-01

    Wisconsin--and, in particular, urban Milwaukee--has been at the forefront of a half-century of public education experiments, from desegregation and "school choice" to vouchers and charter schools. "Lessons from the Heartland: A Turbulent Half-Century of Public Education in an Iconic American City" by Barbara J. Miner, former…

  9. School Violence. Web Lessons.

    ERIC Educational Resources Information Center

    Constitutional Rights Foundation, Los Angeles, CA.

    In answer to the concerns about school violence in the United States (especially since the tragedy in 1999 at Columbine High School in Littleton, Colorado), this Internet curriculum offers lessons and resources that address the topic of school violence and its causes, as well as the search for solutions. The curriculum presents four world wide web…

  10. A Lesson from Mangroves.

    ERIC Educational Resources Information Center

    Davis, Stephen

    1987-01-01

    Discusses the importance of interpretive programs in the Northern Territory of Australia. Describes the typical interpretive approach of local school science curricula, which serve 20,000 Aboriginal children. Addresses the curriculum framework, learning strategies, and process skill development, illustrating them through a lesson on mangroves. (TW)

  11. Recycling Lesson Plans.

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Environmental Resources, Harrisburg.

    This document contains lesson plans about recycling for teachers in grades K-12. Titles include: (1) "Waste--Where Does It Come From? Where Does It Go?" (2) "Litter Detectives," (3) "Classroom Paper Recycling," (4) "Recycling Survey," (5) "Disposal and Recycling Costs," (6) "Composting…

  12. Lively Zoo Lessons.

    ERIC Educational Resources Information Center

    Swengel, Ann

    1992-01-01

    Presents ideas for getting the most out of an elementary school trip to the zoo. The article offers before, during, and after lesson plans which touch on biology (the life cycle), geography (continents and regions of the world), conservation (endangered species), ecology (natural communities), and career guidance (zoo jobs). (SM)

  13. Lively Zoo Lessons.

    ERIC Educational Resources Information Center

    Swengel, Ann

    1992-01-01

    Presents ideas for getting the most out of an elementary school trip to the zoo. The article offers before, during, and after lesson plans which touch on biology (the life cycle), geography (continents and regions of the world), conservation (endangered species), ecology (natural communities), and career guidance (zoo jobs). (SM)

  14. Dracula. [Lesson Plan].

    ERIC Educational Resources Information Center

    Discovery Communications, Inc., Bethesda, MD.

    Based on Bram Stoker's novel "Dracula," this lesson plan presents activities designed to help students understand that some fictional literary characters become so famous that they enter popular culture in other forms (movies, games, toys); and that working on a product such as a game often demands collaborative effort. The main activity of the…

  15. Newspaper Lesson Aids.

    ERIC Educational Resources Information Center

    Communication: Journalism Education Today (C:JET), 1986

    1986-01-01

    Provides photocopy-ready lesson aids on story ideas, interviewing, inverted pyramid writing style, newswriting, sports/scavenger hunt, finding feature material, identifying feature leads, feature lead selection, evaluating feature leads, compiling survey material, cutlines, headlines, paste-up rules, advertising, final semester project, newspaper…

  16. War Literature. [Lesson Plan].

    ERIC Educational Resources Information Center

    Soderquist, Alisa

    Based on Stephen Crane's poems about war and his novel "The Red Badge of Courage," this lesson plan presents activities designed to help students understand that Crane examined war-related themes in prose and poetry; that close study of a poem for oral presentation helps readers see meaning or techniques not noted earlier; and that not all readers…

  17. Lessons from a Lake.

    ERIC Educational Resources Information Center

    Goethals, Susan

    1997-01-01

    Describes a study that included classroom lessons on hydroelectric power, the history and construction of a nearby lake, data recording, the use of field guides, and methods of counting natural populations. The study culminated in a field trip to the lake. (JRH)

  18. Recycling Lesson Plan

    ERIC Educational Resources Information Center

    Okaz, Abeer Ali

    2013-01-01

    This lesson plan designed for grade 2 students has the goal of teaching students about the environmental practice of recycling. Children will learn language words related to recycling such as: "we can recycle"/"we can't recycle" and how to avoid littering with such words as: "recycle paper" and/or "don't throw…

  19. Research Administration: Lessons Learned.

    ERIC Educational Resources Information Center

    Dummer, George H.

    1995-01-01

    The ways in which accountability issues have affected federal-university relationships, particularly in the area of academic research, are examined. Lessons university administrators have learned since issuance of Office of Management and Budget Circular A-21 in 1958, Congressional hearings on the operations of the National Institutes of Health…

  20. Lessons from Katrina

    ERIC Educational Resources Information Center

    Albrecht, Kay

    2005-01-01

    In this article, the author relates the lessons she learned from Hurricane Katrina. During the first few days after the hurricane, it took 2,500 volunteers per hour around the clock to do what needed to be done. That included medical volunteers; crisis counselors and mental health professionals; and volunteers to distribute water and snacks, serve…

  1. Lessons from the Heartland

    ERIC Educational Resources Information Center

    Miner, Barbara

    2013-01-01

    Wisconsin--and, in particular, urban Milwaukee--has been at the forefront of a half-century of public education experiments, from desegregation and "school choice" to vouchers and charter schools. "Lessons from the Heartland: A Turbulent Half-Century of Public Education in an Iconic American City" by Barbara J. Miner, former…

  2. Newspaper Lesson Aids.

    ERIC Educational Resources Information Center

    Communication: Journalism Education Today (C:JET), 1986

    1986-01-01

    Provides photocopy-ready lesson aids on story ideas, interviewing, inverted pyramid writing style, newswriting, sports/scavenger hunt, finding feature material, identifying feature leads, feature lead selection, evaluating feature leads, compiling survey material, cutlines, headlines, paste-up rules, advertising, final semester project, newspaper…

  3. DSCOVR Contamination Lessons Learned

    NASA Technical Reports Server (NTRS)

    Graziani, Larissa

    2015-01-01

    The Triana observatory was built at NASA GSFC in the late 1990's, then placed into storage. After approximately ten years it was removed from storage and repurposed as the Deep Space Climate Observatory (DSCOVR). This presentation outlines the contamination control program lessons learned during the integration, test and launch of DSCOVR.

  4. Photosynthesis. Agricultural Lesson Plans.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This lesson plan is intended for use in conducting classes on photosynthesis. Presented first are an attention step/problem statement and a series of questions and answers designed to convey general information about photosynthesis. The following topics are among those discussed: the photosynthesis process and its importance, the organisms that…

  5. Courtside: A Damaging Lesson

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

    This case presents a costly lesson for teachers and for districts that include a liquidated, or stipulated, damages clause in their teacher employment contracts. Although the court enforced the clause in this case, in this well-reasoned recent decision and in most of the much older, canvassed case law from other jurisdictions, the answer to the…

  6. Lesson 2: Sacred Mountains.

    ERIC Educational Resources Information Center

    Byers, Alton; Gilligan, Nancy; Golston, Syd; Linville, Rex

    1999-01-01

    Presents a lesson in which the students are divided into four Mountain Study Teams in order to examine a sacred mountain. Explains that the students in each group assume a particular role, such as an historian or scientist. Provides a profile on the four mountains and a definition of the seven student roles. (CMK)

  7. Online Conferencing: Lessons Learned.

    ERIC Educational Resources Information Center

    Green, Lyndsay

    This guide summarizes lessons learned from the author's experience of organizing and moderating five non-pedagogical online conferences that use World Wide Web-based conferencing software, whether synchronous or asynchronous. Seven sections cover the following topics: (1) the pros and cons of online conferencing; (2) setting objectives; (3)…

  8. Lessons from a Lake.

    ERIC Educational Resources Information Center

    Goethals, Susan

    1997-01-01

    Describes a study that included classroom lessons on hydroelectric power, the history and construction of a nearby lake, data recording, the use of field guides, and methods of counting natural populations. The study culminated in a field trip to the lake. (JRH)

  9. Brothers Grimm. [Lesson Plan].

    ERIC Educational Resources Information Center

    Discovery Communications, Inc., Bethesda, MD.

    Based on Grimm's fairy tales, this lesson plan presents activities designed to help students understand that fairy tales connect them to earlier generations, help them think about present situations, that magic figures prominently in fairy tales, and that fairy tales can inspire readers to create original works of art. The main activity in the…

  10. "Becky's Legacy": More Lessons

    ERIC Educational Resources Information Center

    Larson, Dale G.

    2005-01-01

    In this commentary on Werth's (this issue) article, the author attempts to continue the work of "meaning making" by describing 10 lessons that were evident to him, based on 25 years of experience as an end-of-life researcher and clinician. He highlights the impact of stress, the importance of communication, the idiosyncratic definition of a "good…

  11. A Makeup Lesson.

    ERIC Educational Resources Information Center

    Eagles, Cheryl

    1991-01-01

    Presents a hands-on lesson that can integrate the use of makeup with studies of the history of Halloween; the history and practices of the theater; Native American or African tribes and their use of paint, makeup, and masks; and the history, skills, and makeup of clowns. (MDH)

  12. Lessons from Proposition 9.

    ERIC Educational Resources Information Center

    Breunig, Robert H.

    1980-01-01

    The lessons of state tax reform learned in California are that education systems need to establish working relationships with all constituencies, work closely with other groups with similar interests, build public faith in education, and encourage and support intelligent and courageous educational leadership. (MSE)

  13. Fitness Day. Lesson Plan.

    ERIC Educational Resources Information Center

    McNamara, Jeanne

    This lesson plan introduces students to the concept of supply and demand by appealing to bodily/kinesthetic intelligences. Students participate in a fitness class and then analyze the economic motives behind making an individual feel better after a fitness activity; i.e., analyzing how much an individual would pay for a drink and snack after a…

  14. A Makeup Lesson.

    ERIC Educational Resources Information Center

    Eagles, Cheryl

    1991-01-01

    Presents a hands-on lesson that can integrate the use of makeup with studies of the history of Halloween; the history and practices of the theater; Native American or African tribes and their use of paint, makeup, and masks; and the history, skills, and makeup of clowns. (MDH)

  15. Cooperative Science Lesson Plans.

    ERIC Educational Resources Information Center

    Cooperative Learning, 1991

    1991-01-01

    Offers several elementary level cooperative science lesson plans. The article includes a recipe for cooperative class learning, instructions for making a compost pile, directions for finding evidence of energy, experiments in math and science using oranges to test density, and discussions of buoyancy using eggs. (SM)

  16. Courtside: Lesson Lost?

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

    In this month's Courtside, the author will stray somewhat from his usual format of describing a single case. Instead, he will be presenting the details of two separate cases, both of which involve similar circumstances, rely on similar legal arguments, and have similar outcomes. Most important, both appear to carry the same lesson. The lessons…

  17. A Lesson from Mangroves.

    ERIC Educational Resources Information Center

    Davis, Stephen

    1987-01-01

    Discusses the importance of interpretive programs in the Northern Territory of Australia. Describes the typical interpretive approach of local school science curricula, which serve 20,000 Aboriginal children. Addresses the curriculum framework, learning strategies, and process skill development, illustrating them through a lesson on mangroves. (TW)

  18. Cooperative Science Lesson Plans.

    ERIC Educational Resources Information Center

    Cooperative Learning, 1991

    1991-01-01

    Offers several elementary level cooperative science lesson plans. The article includes a recipe for cooperative class learning, instructions for making a compost pile, directions for finding evidence of energy, experiments in math and science using oranges to test density, and discussions of buoyancy using eggs. (SM)

  19. Courtside: A Damaging Lesson

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2004-01-01

    This case presents a costly lesson for teachers and for districts that include a liquidated, or stipulated, damages clause in their teacher employment contracts. Although the court enforced the clause in this case, in this well-reasoned recent decision and in most of the much older, canvassed case law from other jurisdictions, the answer to the…

  20. Smart Consumer Lesson Plans.

    ERIC Educational Resources Information Center

    New Jersey Consortium for Consumer Education, Newark.

    Lesson plans are provided for use with different populations of pre-K through senior high school students in four different areas of consumer education. Eight units in advertising are included: A First Look at Ads (pre-K-Grade 3), Don't Judge a Book by Its Cover (Grades 1-3), Fatal Distraction (Junior High), Package Labeling (Junior High), Product…

  1. "Becky's Legacy": More Lessons

    ERIC Educational Resources Information Center

    Larson, Dale G.

    2005-01-01

    In this commentary on Werth's (this issue) article, the author attempts to continue the work of "meaning making" by describing 10 lessons that were evident to him, based on 25 years of experience as an end-of-life researcher and clinician. He highlights the impact of stress, the importance of communication, the idiosyncratic definition of a "good…

  2. Lessons from Katrina

    ERIC Educational Resources Information Center

    Albrecht, Kay

    2005-01-01

    In this article, the author relates the lessons she learned from Hurricane Katrina. During the first few days after the hurricane, it took 2,500 volunteers per hour around the clock to do what needed to be done. That included medical volunteers; crisis counselors and mental health professionals; and volunteers to distribute water and snacks, serve…

  3. Phagocytosis: history's lessons.

    PubMed

    Garg, Manish; Chandawarkar, Rajiv Y

    2013-01-01

    The assimilation of lessons from the past is an essential component of education for scientists of tomorrow. These lessons are not easy to find. History books on science are few and usually highly dramatized and biographies of scientists tend to exaggerate the pomp of scientific discovery. Both underplay the hard and laborious work that is integral to any scientific pursuit. Here we illustrate one such example. A century ago, the Nobel Prize in Medicine was awarded to two scientists: Ilya Metchnikoff, a Russian zoologist, for the discovery ofphagocytosis-a cell-mediated ingestion ofmicrobes; and Paul Ehrlich, a distinguished physician-scientist, for discovering a highly antigen-specific serum-derived antibody-based immune defense. These two diametrically opposing views of the host-pathogen interaction set the stage for a strife that led to seminal advancements in immunology. Mirrored in this journey are important lessons for scientists today--ubiquitously as applicable to modern scientific life as they were a century ago. This commentaryhighlights these lessons--a fitting centenary to a well-deserved recognition.

  4. Lessons Learned in Engineering. Supplement

    NASA Technical Reports Server (NTRS)

    Blair, James C.; Ryan, Robert S.; Schultzenhofer, Luke A.

    2011-01-01

    This Contractor Report (CR) is a compilation of Lessons Learned in approximately 55 years of engineering experience by each James C. Blair, Robert S. Ryan, and Luke A. Schutzenhofer. The lessons are the basis of a course on Lessons Learned that has been taught at Marshall Space Flight Center. The lessons are drawn from NASA space projects and are characterized in terms of generic lessons learned from the project experience, which are further distilled into overarching principles that can be applied to future projects. Included are discussions of the overarching principles followed by a listing of the lessons associated with that principle. The lesson with sub-lessons are stated along with a listing of the project problems the lesson is drawn from, then each problem is illustrated and discussed, with conclusions drawn in terms of Lessons Learned. The purpose of this CR is to provide principles learned from past aerospace experience to help achieve greater success in future programs, and identify application of these principles to space systems design. The problems experienced provide insight into the engineering process and are examples of the subtleties one experiences performing engineering design, manufacturing, and operations. The supplemental CD contains accompanying PowerPoint presentations.

  5. Lessons Learned in Engineering. Supplement

    NASA Technical Reports Server (NTRS)

    Blair, James C.; Ryan, Robert S.; Schultzenhofer, Luke A.

    2011-01-01

    This Contractor Report (CR) is a compilation of Lessons Learned in approximately 55 years of engineering experience by each James C. Blair, Robert S. Ryan, and Luke A. Schutzenhofer. The lessons are the basis of a course on Lessons Learned that has been taught at Marshall Space Flight Center. The lessons are drawn from NASA space projects and are characterized in terms of generic lessons learned from the project experience, which are further distilled into overarching principles that can be applied to future projects. Included are discussions of the overarching principles followed by a listing of the lessons associated with that principle. The lesson with sub-lessons are stated along with a listing of the project problems the lesson is drawn from, then each problem is illustrated and discussed, with conclusions drawn in terms of Lessons Learned. The purpose of this CR is to provide principles learned from past aerospace experience to help achieve greater success in future programs, and identify application of these principles to space systems design. The problems experienced provide insight into the engineering process and are examples of the subtleties one experiences performing engineering design, manufacturing, and operations. The supplemental CD contains accompanying PowerPoint presentations.

  6. First estimates of the probability of survival in a small-bodied, high-elevation frog (Boreal Chorus Frog, Pseudacris maculata), or how historical data can be useful

    USGS Publications Warehouse

    Muths, Erin L.; Scherer, R. D.; Amburgey, S. M.; Matthews, T.; Spencer, A. W.; Corn, P.S.

    2016-01-01

    In an era of shrinking budgets yet increasing demands for conservation, the value of existing (i.e., historical) data are elevated. Lengthy time series on common, or previously common, species are particularly valuable and may be available only through the use of historical information. We provide first estimates of the probability of survival and longevity (0.67–0.79 and 5–7 years, respectively) for a subalpine population of a small-bodied, ostensibly common amphibian, the Boreal Chorus Frog (Pseudacris maculata (Agassiz, 1850)), using historical data and contemporary, hypothesis-driven information–theoretic analyses. We also test a priori hypotheses about the effects of color morph (as suggested by early reports) and of drought (as suggested by recent climate predictions) on survival. Using robust mark–recapture models, we find some support for early hypotheses regarding the effect of color on survival, but we find no effect of drought. The congruence between early findings and our analyses highlights the usefulness of historical information in providing raw data for contemporary analyses and context for conservation and management decisions.

  7. Sperm competition and the evolution of precopulatory weapons: Increasing male density promotes sperm competition and reduces selection on arm strength in a chorusing frog.

    PubMed

    Buzatto, Bruno A; Roberts, J Dale; Simmons, Leigh W

    2015-10-01

    Sperm competition theory assumes a trade-off between precopulatory traits that increase mating success and postcopulatory traits that increase fertilization success. Predictions for how sperm competition might affect male expenditure on these traits depend on the number of competing males, the advantage gained from expenditure on weapons, and the level of sperm competition. However, empirical tests of sperm competition theory rarely examine precopulatory male expenditure. We investigated how variation in male density affects precopulatory sexual selection on male weaponry and the level of sperm competition in the chorusing frog Crinia georgiana, where males use their arms as weapons in male-male combat. We measured body size and arm girth of 439 males, and recorded their mating success in the field. We found density-dependent selection acting on arm girth. Arm girth was positively associated with mating success, but only at low population densities. Increased male density was associated with higher risk and intensity of sperm competition arising from multimale amplexus, and a reversal in the direction of selection on arm girth. Opposing patterns of pre- and postcopulatory selection may account for the negative covariation between arm girth and testes across populations of this species.

  8. [The French lessons of anatomy].

    PubMed

    Bouchet, Alain

    2003-01-01

    The "Lessons of Anatomy" can be considered as a step of Medicine to Art. For several centuries the exhibition of a corpse's dissection was printed on the title-page of published works. Since the seventeenth century, the "Lessons of Anatomy" became a picture on the title-page in order to highlight the well-known names of the european anatomists. The study is limited to the French Lessons of Anatomy found in books or pictures after the invention of printing.

  9. Lesson plans in surgical training.

    PubMed

    Lester, S E; Robson, A K R

    2007-06-01

    Lesson plans in surgery enable trainers and trainees to agree on goals that balance training needs with service commitments. Lesson plans are individualised to the trainee and encourage ownership of learning. They are based on SMART criteria and therefore have a sound educational footing. Most of the work in creating a lesson plan falls to the trainee. The total time for creation of each plan is approximately 20 min. Our use of lesson plans for surgical training has been met with favourable response from both trainer and trainees.

  10. Lessons Learned Class

    SciTech Connect

    Barat, K

    2005-02-11

    Basic laser safety training at Lawrence Livermore National Laboratory (LLNL) is provided through a multiple module web-based course. The web-based course presents a wide and detailed review of laser safety topics including: biological effects, laser protective eyewear, fiber optic laser use, control measures, and more. It opens with a re-enactment of a laser accident. While supportive of this web-based course and actively involved in its development, the NIF Directorate has developed a classroom presentation adjunct to the course for laser users working in NIF. This author considers the LLNL web-based laser safety course to be one of, if not the best, such course available. Still, experience has shown that a ''lessons learned program'' is a great re-enforcer of laser safety. What-is-more, the laser lessons learned class provides important ''face-to-face'' interactions and discussion. The object of the ''laser lessons learned course'' is not to repeat the web course but present laser related lessons learned to the staff. In this author's opinion, lessons learned is the strongest safety re-enforcement one can present to the laser user community. For example, it can show how a practice that might be common to laser users can lead to a dramatic injury and a programmatic long-term work stoppage. The course outline is as follows: (1) A video of laser application with minimum safety practices; (2) Who is typically involved in laser incidents; (3) Commonly given reasons for violating laser safety procedures; (4) A review of perceived hazard incidents (i.e. flashlamp light mistaken for laser scatter); (5) A review of several laser accidents; (6) What to do if an injury is suspected and what we can do about injuries; (7) Discussion of whether laser accidents can be eliminated (and of course they can be eliminated); and (8) Summation. To date, the class has received positive feedback from experienced and inexperienced laser users. This, along with the broader lessons learned

  11. Lessons of Operation Torch

    DTIC Science & Technology

    1943-01-19

    not display a currently valid OMB control number. 1. REPORT DATE JAN 1943 2. REPORT TYPE 3. DATES COVERED - 4. TITLE AND SUBTITLE Lessons...Staffs. Staffs, down to include battalions, should be continuously trained in supply and logistics by ma aitaining current Personnel and Ton- nage Tables...those planning the expedition, but on accout of lack cf time, and oering to the necessity for security. b. It wi&ll be noted that practica.lly every

  12. MSFC Skylab lessons learned

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Key lessons learned during the Skylab Program that could have impact on on-going and future programs are presented. They present early and sometimes subjective opinions; however, they give insights into key areas of concern. These experiences from a complex space program management and space flight serve as an early assessment to provide the most advantage to programs underway. References to other more detailed reports are provided.

  13. Lesson Study: Researching Learning about Teaching from Research Mathematics Lessons

    ERIC Educational Resources Information Center

    Corcoran, Dolores

    2009-01-01

    Lesson study is a form of teacher professional development that is intrinsic to the Japanese educational system in first and second level schools and in teacher education. Lesson study has been credited with the success of Japanese pupils in international comparative tests of mathematics achievement (Stigler and Hiebert, 1999). It is gaining…

  14. Best Practice Lesson Plans: A Lesson Plan in Cognitive Restructuring

    ERIC Educational Resources Information Center

    Sayre, Gary W.

    2006-01-01

    This particular lesson was developed for Cognitive Skills I, a central course in cognitive restructuring at the Mt. Olive Correctional Center. In this lesson the author developed a series of classroom activities to allow students to examine and assess current beliefs they possess, and to understand how these beliefs--whether judged rational or…

  15. Using Technology to Support Teachers' Lesson Modifications during Lesson Study

    ERIC Educational Resources Information Center

    Skultety, Lisa; Gonzalez, Gloriana; Vargas, Gabriela

    2017-01-01

    Lesson study is a professional development activity that increases teachers' attention to student thinking. However, coordinating teachers' live observations of a lesson can be challenging. Using the framework of "distributed cognition," we investigate whether technology supports teachers' examination of student thinking and aids the…

  16. Best Practice Lesson Plans: A Lesson Plan in Cognitive Restructuring

    ERIC Educational Resources Information Center

    Sayre, Gary W.

    2006-01-01

    This particular lesson was developed for Cognitive Skills I, a central course in cognitive restructuring at the Mt. Olive Correctional Center. In this lesson the author developed a series of classroom activities to allow students to examine and assess current beliefs they possess, and to understand how these beliefs--whether judged rational or…

  17. Design for Life. Abortion. A Student's Lesson Plan [and] A Teacher's Lesson Plan [and] A Lawyer's Lesson Plan.

    ERIC Educational Resources Information Center

    Howard, Estelle; And Others

    One of a series of secondary level teaching units presenting case studies with pro and con analyses of particular legal problems, the document consists of a student's lesson plan, a teacher's lesson plan, and a lawyer's lesson plan for a unit on abortion. The lessons are designed to expose students to the Supreme Court's decision concerning…

  18. Mining Mathematics in Textbook Lessons

    ERIC Educational Resources Information Center

    Ronda, Erlina; Adler, Jill

    2017-01-01

    In this paper, we propose an analytic tool for describing the mathematics made available to learn in a "textbook lesson". The tool is an adaptation of the Mathematics Discourse in Instruction (MDI) analytic tool that we developed to analyze what is made available to learn in teachers' lessons. Our motivation to adapt the use of the MDI…

  19. Mansfield ISD. Integrated Lesson Plans.

    ERIC Educational Resources Information Center

    East Texas State Univ., Commerce. Educational Development and Training Center.

    This packet contains 27 lesson plans for integrated academic and vocational education courses. Lesson plans for the following courses are included: horticulture, algebra, physical science, general mechanical repair, foods and nutrition, home economics, and microcomputer applications. Some of the topics covered are as follows: seed germination,…

  20. "Alice in Wonderland." [Lesson Plan].

    ERIC Educational Resources Information Center

    Heyman, Judith B.

    Based on Lewis Carroll's novel "Alice's Adventures in Wonderland," this lesson plan presents activities designed to help students understand that he used nonsense and absurdity to comment on reality; and that surrealist painters are also known for including absurd elements in their works. The main activity of the lesson involves students…

  1. Greenville ISD. Integrated Lesson Plans.

    ERIC Educational Resources Information Center

    East Texas State Univ., Commerce. Educational Development and Training Center.

    This packet contains nine lesson plans for integrated academic and vocational education courses. Lesson plans for the following courses are included: industrial technology, automotive technology, English, mathematical applications, science, home economics, and mathematics. Some of the topics covered are as follows: mechanical drawing, automobile…

  2. Austin ISD. Integrated Lesson Plans.

    ERIC Educational Resources Information Center

    East Texas State Univ., Commerce. Educational Development and Training Center.

    This packet contains 14 lesson plans for integrated academic and vocational education courses. Lesson plans for the following courses are included: integrated physics and principles of technology; algebra and principles of technology; principles of technology, language arts, and economics; physics and industrial electronics; physics and…

  3. Greenville ISD. Integrated Lesson Plans.

    ERIC Educational Resources Information Center

    East Texas State Univ., Commerce. Educational Development and Training Center.

    This packet contains nine lesson plans for integrated academic and vocational education courses. Lesson plans for the following courses are included: industrial technology, automotive technology, English, mathematical applications, science, home economics, and mathematics. Some of the topics covered are as follows: mechanical drawing, automobile…

  4. Geometrical Analogies in Mathematics Lessons

    ERIC Educational Resources Information Center

    Eid, Wolfram

    2007-01-01

    A typical form of thinking to approach problem solutions humanly is thinking in analogous structures. Therefore school, especially mathematical lessons should help to form and to develop corresponding heuristic abilities of the pupils. In the contribution, a summary of possibilities of mathematics lessons regarding this shall particularly be…

  5. An Overview of Chanute Lessons.

    ERIC Educational Resources Information Center

    Klecka, Joseph A.

    A survey of current lesson development was considered essential to determine the quality and effectiveness of instructional material produced on the PLATO IV computer-assisted instruction system. The trial period lasted for several years. Both civilian and military personnel developed the lessons, in consultation with the Military Training Centers…

  6. Community College Biology Lesson Catalogue.

    ERIC Educational Resources Information Center

    Herrick, Kathie G.

    This catalog contains descriptions of the available biology lessons on PLATO IV, compiled to assist instructors in planning their curricula. Information is provided for 87 lessons in the following areas: experimental tools and techniques; chemical basis of life; cellular structure and function; bioenergetics - enzymes and cellular metabolism;…

  7. Improving Teaching through Lesson Study

    ERIC Educational Resources Information Center

    Rock, Tracy C.; Wilson, Cathy

    2005-01-01

    This article presents a professional development initiative developed by a university-school partnership based on the Japanese lesson-study model described by Stigler and Hiebert (1999) in "The Teaching Gap." Lesson study ("jugyoukenkyu"), an inquiry model of teacher professional development, is used extensively throughout…

  8. Heart of Darkness. [Lesson Plan].

    ERIC Educational Resources Information Center

    Discovery Communications, Inc., Bethesda, MD.

    Based on Joseph Conrad's novel "Heart of Darkness," this lesson plan presents activities designed to help students understand that critics have debated some of Conrad's choices in the novel; and that the novel reflects the world as Conrad saw it. The main activity of the lesson involves students rewriting the ending of the novel so that Marlow…

  9. Can You Haiku? [Lesson Plan].

    ERIC Educational Resources Information Center

    National Endowment for the Humanities (NFAH), Washington, DC.

    In this lesson plan, students learn the rules and conventions of haiku, study examples by Japanese masters, and create haiku of their own. Its 4 lessons seek to help students be able to: (1) describe the traditional rules and conventions of haiku; (2) interpret examples of haiku; (3) characterize the image-evoking power of haiku; (4) develop a…

  10. Lesson Study and History Education

    ERIC Educational Resources Information Center

    Halvorsen, Anne-Lise; Kesler Lund, Alisa

    2013-01-01

    This article examines the experiences of a group of fifth-grade teachers who used lesson study, a teacher-driven form of professional development, to teach history in a project supported by a Teaching American History Grant. The project addressed the following questions: What does a lesson study cycle for history education look like? What…

  11. Lesson Study and History Education

    ERIC Educational Resources Information Center

    Halvorsen, Anne-Lise; Kesler Lund, Alisa

    2013-01-01

    This article examines the experiences of a group of fifth-grade teachers who used lesson study, a teacher-driven form of professional development, to teach history in a project supported by a Teaching American History Grant. The project addressed the following questions: What does a lesson study cycle for history education look like? What…

  12. Lessons from the Younger Set.

    ERIC Educational Resources Information Center

    Handscombe, Jean

    1993-01-01

    Six lessons or statements are offered based on experiences teaching school-aged students in English-medium schools in Canada. The lessons refer to judicious use of first language, language teacher connections with the learner's view of the world, second-language learning and curricular content, etc. (Contains seven references.) (LB)

  13. Mansfield ISD. Integrated Lesson Plans.

    ERIC Educational Resources Information Center

    East Texas State Univ., Commerce. Educational Development and Training Center.

    This packet contains 27 lesson plans for integrated academic and vocational education courses. Lesson plans for the following courses are included: horticulture, algebra, physical science, general mechanical repair, foods and nutrition, home economics, and microcomputer applications. Some of the topics covered are as follows: seed germination,…

  14. Bead Game Simulation. Lesson Plan.

    ERIC Educational Resources Information Center

    Ripp, Ken

    This lesson plan offers students the opportunity to participate in the three basic economic systems (market, command, and tradition). By working in each of the systems, students will internalize the fundamental values present in each system and will gain insights into the basic advantages and disadvantages of each system. The lesson plan provides…

  15. Masterwork Art Lesson: Kandinsky Watercolors.

    ERIC Educational Resources Information Center

    LiPira, Michael

    2003-01-01

    Presents an art lesson used with sixth-grade students which also can be used with other grade levels. Explains that the artwork of Wassily Kandinsky served as inspiration for this lesson. Explains that the students learned about abstract art and used watercolors to create their own paintings in the style of Kandinsky. (CMK)

  16. Austin ISD. Integrated Lesson Plans.

    ERIC Educational Resources Information Center

    East Texas State Univ., Commerce. Educational Development and Training Center.

    This packet contains 14 lesson plans for integrated academic and vocational education courses. Lesson plans for the following courses are included: integrated physics and principles of technology; algebra and principles of technology; principles of technology, language arts, and economics; physics and industrial electronics; physics and…

  17. Archeology and Storytelling. [Lesson Plan].

    ERIC Educational Resources Information Center

    Lamb, Sandy; Lamb, Jay

    This lesson plan presents activities designed to help students understand that both individual families and whole cultures learn about their pasts by collecting and analyzing stories and artifacts; and that not all archeological finds readily reveal their history to archeologists. The main activity in the lesson involves students in making an oral…

  18. Learning the Blues. [Lesson Plan].

    ERIC Educational Resources Information Center

    2001

    This lesson introduces students to the "blues," one of the most distinctive and influential elements of African-American musical tradition. With this lesson plan, students can take a virtual field trip to Memphis, Tennessee, one of the prominent centers of blues activities, and explore the history of the blues in the work of W. C. Handy…

  19. A Lesson on Environmental Protection

    ERIC Educational Resources Information Center

    Zhongzheng, Wang

    2004-01-01

    In this article, the author presents a first-hand account of teaching environmental protection in the Wushan Mountain area of China. Combining the knowledge in the textbook with social practice, the lessons focused on enabling the students to develop a sense of responsibility and duty through personal experiences. What began as a lesson in…

  20. Masterwork Art Lesson: Kandinsky Watercolors.

    ERIC Educational Resources Information Center

    LiPira, Michael

    2003-01-01

    Presents an art lesson used with sixth-grade students which also can be used with other grade levels. Explains that the artwork of Wassily Kandinsky served as inspiration for this lesson. Explains that the students learned about abstract art and used watercolors to create their own paintings in the style of Kandinsky. (CMK)

  1. Keiko, Killer Whale. [Lesson Plan].

    ERIC Educational Resources Information Center

    Discovery Communications, Inc., Bethesda, MD.

    This lesson plan presents activities designed to help students understand that Keiko, the killer whale, lived for a long time in an aquarium and had to be taught to live independently; and that computer users can get updates on how Keiko is doing. The main activity of the lesson involves middle school students working in small groups to produce a…

  2. A Lesson on Environmental Protection

    ERIC Educational Resources Information Center

    Zhongzheng, Wang

    2004-01-01

    In this article, the author presents a first-hand account of teaching environmental protection in the Wushan Mountain area of China. Combining the knowledge in the textbook with social practice, the lessons focused on enabling the students to develop a sense of responsibility and duty through personal experiences. What began as a lesson in…

  3. Hybrid Fluid-Particle Simulation of Whistler-Mode Waves in a Compressed Dipole Magnetic Field: Implications for Dayside High-Latitude Chorus

    NASA Astrophysics Data System (ADS)

    da Silva, C. L.; Denton, R. E.; Hudson, M.; Millan, R. M.

    2016-12-01

    In this work we present a methodology for simulating self-consistent generation of whistler-mode waves due to electron temperature anisotropy in the inner magnetosphere. We present simulations results using a hybrid fluid/particle-in-cell code [Hu and Denton, JGR, 114, A12217, 2009; Wu et al., JGR, 120, 1908-1923, 2015], that treats the hot, anisotropic (i.e., ring current) electron population as particles and the background (i.e., the cold, inertialess) electrons as fluid. Since, the hot electrons are only a small fraction of the total population, warm (and isotropic) particle electrons are added to the simulation to increase the fraction of particles with mass and improve the dispersion relation of generated waves. Ions are treated as a fixed background of positive charge density. The plasma transport equations are coupled to Maxwell's equations and solved in a meridional plane. We design a curvilinear coordinate system that follows the topological curvature of Earth's geomagnetic field lines, based on an analytic expression for the compressed dipole magnetic field [e.g., McCollough et al., JGR, 117, A01208, 2012, equations (1)-(5)]. Hence, we are able to simulate whistler wave generation at dusk (pure dipole field lines) and dayside (compressed dipole), by simply adjusting one scalar quantity. We demonstrate how, on the dayside, whistler-mode waves can be locally generated at high latitudes, within pockets of minimum magnetic field [see e.g., Tsurutani and Smith, JGR, 82, 32, 1977], and propagate equatorward. We finally use our simulation results to discuss the differences between dayside and nightside chorus.

  4. Geographic Alliance of Iowa. Lesson Plans.

    ERIC Educational Resources Information Center

    Weller, Kay E.; Howe-Ford, Nancy

    This collection of five lesson plans in geography can be adapted for use with K-12 students. Each lesson plan explains the lesson and provides basic instructions. The lesson plans are titled: "Teaching Geography Using Literature in K-University Classrooms" (Kay Weller); "Geography and a Mystery Novel" (Kay Weller);…

  5. How Creative Are Your Art Lessons?

    ERIC Educational Resources Information Center

    Asch, Rosalie

    1976-01-01

    How a teacher achieves a balance between structure and freedom in his art lessons requires a critical awareness of the methods he chooses. Discusses the problems in teaching art lessons, the basic characteristics of creative art lessons, and provides a checklist for analyzing the effectiveness of an art lesson. (Author/RK)

  6. Becky's legacy: more lessons.

    PubMed

    Larson, Dale G

    2005-10-01

    In this commentary on Werth's (this issue) article, the author attempts to continue the work of "meaning making" by describing 10 lessons that were evident to him, based on 25 years of experience as an end-of-life researcher and clinician. He highlights the impact of stress, the importance of communication, the idiosyncratic definition of a "good death," the role of patient-centered care, the power of self-efficacy, the need to integrate theory and experience, the use of interdisciplinary teams, the impact of altruism and having a sense of purpose, the need to listen, and the healing effects of communicating about loss.

  7. ACES program - Lessons learned

    NASA Technical Reports Server (NTRS)

    Jones, Victoria L.; Rice, Sally C.; Waites, Henry B.

    1988-01-01

    The ACES Program involved the experimental evaluation of three LSS (large space structures) control design techniques at the LSS GTF (ground test facility) at NASA/MSFC. The three techniques were developed under the ACOSS (active control of space structures) Program specifically for application to LSS. The techniques included FAMESS (filter accommodated model error sensitivity suppression), HAC/LAC (high authority control/low authority control), and positivity. Some of the lessons that have been learned during the course of the ACES program are examined.

  8. Shuttle Lesson Learned - Toxicology

    NASA Technical Reports Server (NTRS)

    James, John T.

    2010-01-01

    This is a script for a video about toxicology and the space shuttle. The first segment is deals with dust in the space vehicle. The next segment will be about archival samples. Then we'll look at real time on-board analyzers that give us a lot of capability in terms of monitoring for combustion products and the ability to monitor volatile organics on the station. Finally we will look at other issues that are about setting limits and dealing with ground based lessons that pertain to toxicology.

  9. Safeguards Culture: Lessons Learned

    SciTech Connect

    Mladineo, Stephen V.

    2009-05-27

    Abstract: At the 2005 INMM/ESARDA Workshop in Santa Fe, New Mexico, I presented a paper entitled “Changing the Safeguards Culture: Broader Perspectives and Challenges.” That paper described a set of theoretical models that can be used as a basis for evaluating changes to safeguards culture. This paper builds on that theoretical discussion to address practical methods for influencing culture. It takes lessons from methods used to influence change in safety culture and security culture, and examines the applicability of these lessons to changing safeguards culture. Paper: At the 2005 INMM/ESARDA Workshop on “Changing the Safeguards Culture: Broader Perspectives and Challenges,” in Santa Fe, New Mexico, I presented a paper entitled “Changing the Safeguards Culture: Broader Perspectives and Challenges.” That paper, coauthored by Karyn R. Durbin and Andrew Van Duzer, described a set of theoretical models that can be used as a basis for evaluating changes to safeguards culture. This paper updates that theoretical discussion, and seeks to address practical methods for influencing culture. It takes lessons from methods used to influence change in safety culture and security culture, and examines the applicability of these lessons to changing safeguards culture. Implicit in this discussion is an understanding that improving a culture is not an end in itself, but is one method of improving the underlying discipline, that is safety, security, or safeguards. Culture can be defined as a way of life, or general customs and beliefs of a particular group of people at a particular time. There are internationally accepted definitions of safety culture and nuclear security culture. As yet, there is no official agreed upon definition of safeguards culture. At the end of the paper I will propose my definition. At the Santa Fe Workshop the summary by the Co-Chairs of Working Group 1, “The Further Evolution of Safeguards,” noted: “It is clear that ‘safeguards culture

  10. GPS lessons learned

    NASA Technical Reports Server (NTRS)

    Heflin, Michael B.

    2003-01-01

    Global geodesy has improved dramatically over the past decade starting with the GPS for IERS and Geodynamics demonstration campaign in 1991 (GIG 91). At the time it took over a week of CPU time to process a network solution based on 21 global receivers and orbit overlaps were in the 40 cm range. Today it is possible to process a network solution based on 80 global receivers in less then one day of CPU time and orbit overlaps are in the 4 cm range. Special methods are under development for efficient processing of increasingly large regional networks which may contain hundreds or thousands of GPS receivers. Along the way there have been many lessons learned about GPS satellites, receivers, monuments, antennas, radomes, analysis, reference frames, error sources, and interpretation. A wide range of scientific disciplines have been impacted including studies of plate motion, post-glacial rebound, seasonal loading, deformation in plate boundary zones, coseismic displacements due to major earthquakes, postseiemic relaxation, and interseismic strain accumulation related to assessment of seismic hazards. Lessons learned will be presented in the context of new dense networks such as the Plate Boundary Observation (PBO).

  11. GPS lessons learned

    NASA Technical Reports Server (NTRS)

    Heflin, Michael B.

    2003-01-01

    Global geodesy has improved dramatically over the past decade starting with the GPS for IERS and Geodynamics demonstration campaign in 1991 (GIG 91). At the time it took over a week of CPU time to process a network solution based on 21 global receivers and orbit overlaps were in the 40 cm range. Today it is possible to process a network solution based on 80 global receivers in less then one day of CPU time and orbit overlaps are in the 4 cm range. Special methods are under development for efficient processing of increasingly large regional networks which may contain hundreds or thousands of GPS receivers. Along the way there have been many lessons learned about GPS satellites, receivers, monuments, antennas, radomes, analysis, reference frames, error sources, and interpretation. A wide range of scientific disciplines have been impacted including studies of plate motion, post-glacial rebound, seasonal loading, deformation in plate boundary zones, coseismic displacements due to major earthquakes, postseiemic relaxation, and interseismic strain accumulation related to assessment of seismic hazards. Lessons learned will be presented in the context of new dense networks such as the Plate Boundary Observation (PBO).

  12. St. Louis FUSRAP Lessons Learned

    SciTech Connect

    Eberlin, J.; Williams, D.; Mueller, D.

    2003-02-26

    The purpose of this paper is to present lessons learned from fours years' experience conducting Remedial Investigation and Remedial Action activities at the St. Louis Downtown Site (SLDS) under the Formerly Utilized Sites Remedial Action Program (FUSRAP). Many FUSRAP sites are experiencing challenges conducting Remedial Actions within forecasted volume and budget estimates. The St. Louis FUSRAP lessons learned provide insight to options for cost effective remediation at FUSRAP sites. The lessons learned are focused on project planning (budget and schedule), investigation, design, and construction.

  13. Apollo 1 Lessons Learned Show

    NASA Image and Video Library

    2017-01-27

    Mike Ciannilli, the Apollo, Challenger, Columbia Lessons Learned Program manager, far right, is pictured with panelists from the Apollo 1 Lessons Learned event in the Training Auditorium at NASA's Kennedy Space Center in Florida. In the center, are Ernie Reyes, retired, former Apollo 1 senior operations manager; and John Tribe, retired, former Apollo 1 Reaction and Control System lead engineer. At far left is Zulie Cipo, the Apollo, Challenger, Columbia Lessons Learned Program event support team lead. The theme of the program was "To there and Back Again." The event helped pay tribute to the Apollo 1 crew, Gus Grissom, Ed White II, and Roger Chaffee.

  14. Higher Education ERP: Lessons Learned.

    ERIC Educational Resources Information Center

    Swartz, Dave; Orgill, Ken

    2001-01-01

    Shares experiences and lessons learned by chief information officers of large universities about enterprise resource planning (ERP). Specifically, provides a framework for approaching an ERP that could save universities millions of dollars. (EV)

  15. Higher Education ERP: Lessons Learned.

    ERIC Educational Resources Information Center

    Swartz, Dave; Orgill, Ken

    2001-01-01

    Shares experiences and lessons learned by chief information officers of large universities about enterprise resource planning (ERP). Specifically, provides a framework for approaching an ERP that could save universities millions of dollars. (EV)

  16. Make That Shock Lesson Shocking

    ERIC Educational Resources Information Center

    Moskowitz, Gertrude

    1975-01-01

    Notes a tendency among foreign language teachers to attempt to cover too much material too quickly with beginning students. A lesson used with prospective foreign language teachers is described which recalls the difficulties of beginning language students. (RM)

  17. Make That Shock Lesson Shocking

    ERIC Educational Resources Information Center

    Moskowitz, Gertrude

    1975-01-01

    Notes a tendency among foreign language teachers to attempt to cover too much material too quickly with beginning students. A lesson used with prospective foreign language teachers is described which recalls the difficulties of beginning language students. (RM)

  18. [Lessons from Field Studies].

    PubMed

    Yoshimura, Takesumi

    2015-01-01

    During my academic career for more than 40 years, I was involved in 18 epidemiological field studies, partially or fully. Among these field studies, four (1. Medical services in remote rural areas in Okinawa, 2. Yusho episode, 3. JICA Onchocerciasis Control Project in Guatemala, and 4. Miyako cohort study in Fukuoka) are introduced in this paper, including the latest situation after the presentation. Through these field works experienced by the author, the following lessons were gained. 1. Strong human reliance between researchers and the targeted population is essential in carrying out epidemiological surveys successfully in the field. 2. Data obtained from the survey should be carefully examined and analyzed so that those data may reflect the real situation.

  19. Lessons learned and applied

    PubMed Central

    Hebert, Corey Joseph; Hall, Corey M.; Odoms, La’ Nyia J.

    2012-01-01

    Most vaccines available in the United States (US) have been incorporated into vaccination schedules for infants and young children, age groups particularly at risk of contracting infectious diseases. High universal vaccination coverage is responsible for substantially reducing or nearly eliminating many of the diseases that once killed thousands of children each year in the US. Despite the success of infant vaccinations, periods of low vaccination coverage and the limited immunogenicity and duration of protection of certain vaccines have resulted in sporadic outbreaks, allowing some diseases to spread in communities. These challenges suggest that expanded vaccination coverage to younger infants and adolescents, and more immunogenic vaccines, may be needed in some instances. This review focuses on the importance of infant immunization and explores the successes and challenges of current early childhood vaccination programs and how these lessons may be applied to other invasive diseases, such as meningococcal disease. PMID:22617834

  20. Apollo 1 Lessons Learned Show

    NASA Image and Video Library

    2017-01-27

    Mike Ciannilli, at left, the Apollo, Challenger, Columbia Lessons Learned Program manager, presents a certificate to Charlie Duke, former Apollo 16 astronaut and member of the Apollo 1 Emergency Egress Investigation Team, during the Apollo 1 Lessons Learned presentation in the Training Auditorium at NASA's Kennedy Space Center in Florida. The program's theme was "To There and Back Again." The event helped pay tribute to the Apollo 1 crew, Gus Grissom, Ed White II, and Roger Chaffee.

  1. Apollo 1 Lessons Learned Show

    NASA Image and Video Library

    2017-01-27

    Mike Ciannilli, at left, the Apollo, Challenger, Columbia Lessons Learned Program manager, presents a certificate to John Tribe, retired, Apollo 1 Reaction and Control System lead engineer, during the Apollo 1 Lessons Learned presentation in the Training Auditorium at NASA's Kennedy Space Center in Florida. The theme of the program was "To there and Back Again." The event helped pay tribute to the Apollo 1 crew, Gus Grissom, Ed White II, and Roger Chaffee.

  2. Apollo 1 Lessons Learned Show

    NASA Image and Video Library

    2017-01-27

    Mike Ciannilli, the Apollo, Challenger, Columbia Lessons Learned program manager, at left, presents a certificate to Ernie Reyes, retired, former Apollo 1 senior operations manager, during the Apollo 1 Lessons Learned presentation in the Training Auditorium at NASA's Kennedy Space Center in Florida. The theme of the program was "To there and Back Again." The event helped pay tribute to the Apollo 1 crew, Gus Grissom, Ed White II, and Roger Chaffee.

  3. Lesson "Balance in Nature

    NASA Astrophysics Data System (ADS)

    Chapanova, V.

    2012-04-01

    Lesson "Balance in Nature" This simulation game-lesson (Balance in Nature) gives an opportunity for the students to show creativity, work independently, and to create models and ideas. It creates future-oriented thought connected to their experience, allowing them to propose solutions for global problems and personal responsibility for their activities. The class is divided in two teams. Each team chooses questions. 1. Question: Pollution in the environment. 2. Question: Care for nature and climate. The teams work on the chosen tasks. They make drafts, notes and formulate their solutions on small pieces of paper, explaining the impact on nature and society. They express their points of view using many different opinions. This generates alternative thoughts and results in creative solutions. With the new knowledge and positive behaviour defined, everybody realizes that they can do something positive towards nature and climate problems and the importance of individuals for solving global problems is evident. Our main goal is to recover the ecological balance, and everybody explains his or her own well-grounded opinions. In this work process the students obtain knowledge, skills and more responsible behaviour. This process, based on his or her own experience, dialogue and teamwork, helps the participant's self-development. Making the model "human↔ nature" expresses how human activities impact the natural Earth and how these impacts in turn affect society. Taking personal responsibility, we can reduce global warming and help the Earth. By helping nature we help ourselves. Teacher: Veselina Boycheva-Chapanova " Saint Patriarch Evtimii" Scholl Str. "Ivan Vazov"-19 Plovdiv Bulgaria

  4. Lessons Learned from FUSRAP

    SciTech Connect

    Castillo, Darina; Carpenter, Cliff; Miller, Michele

    2016-03-06

    The US DOE Office of Legacy Management (LM) is the long-term steward for 90 sites remediated under numerous regulatory regimes including the Formerly Utilized Sites Remedial Action Program (FUSRAP) sites. In addition, LM holds considerable historical information, gathered in the 1970s, to determine site eligibility for remediation under FUSRAP. To date, 29 FUSRAP sites are in LM’s inventory of sites for long-term surveillance and maintenance (LTS&M), and 25 are with the US Army Corps of Engineers (USACE) for remediation or in the process of being transitioned to LM. It is forecasted that 13 FUSRAP sites will transfer from the USACE to LM over the next 10 years; however, the timing of the transfers is strongly dependent upon federal funding of the ongoing remedial actions. Historically, FUSRAP sites were generally cleaned up for “unrestricted” industrial use or remediated to the “cleanup standards” at that time, and their use remained unchanged. Today, these sites as well as the adjacent properties are now changing or envisioned to have changes in land use, typically from industrial to commercial or residential uses. The implication of land-use change affects DOE’s LTS&M responsibility for the sites under LM stewardship as well as the planning for the additional sites scheduled to transition in time. Coinciding with land-use changes at or near FUSRAP sites is an increased community awareness of these sites. As property development increases near FUSRAP sites, the general public and interested stakeholders regularly inquire about the sufficiency of cleanups that impact their neighborhoods and communities. LM has used this experience to address a series of lessons learned to improve our program management in light of the changing conditions of our sites. We describe these lessons learned as (1) improved stakeholder relations, (2) enhanced LTS&M requirements for the sites, and (3) greater involvement in the transition process.

  5. Designing and Adapting Tasks in Lesson Planning: A Critical Process of Lesson Study

    ERIC Educational Resources Information Center

    Fujii, Toshiakira

    2016-01-01

    There is no doubt that a lesson plan is a necessary product of Lesson Study. However, the collaborative work among teachers that goes into creating that lesson plan is largely under-appreciated by non-Japanese adopters of Lesson Study, possibly because the effort involved is invisible to outsiders, with our attention going to its most visible…

  6. Designing and Adapting Tasks in Lesson Planning: A Critical Process of Lesson Study

    ERIC Educational Resources Information Center

    Fujii, Toshiakira

    2016-01-01

    There is no doubt that a lesson plan is a necessary product of Lesson Study. However, the collaborative work among teachers that goes into creating that lesson plan is largely under-appreciated by non-Japanese adopters of Lesson Study, possibly because the effort involved is invisible to outsiders, with our attention going to its most visible…

  7. A Study of the Handling of Lessons Processing in Lessons Learned Systems and Application to Lessons Learned System Design

    DTIC Science & Technology

    2002-09-01

    Lessons Learned Program ................................................................70...Learned System is guided by a standard. The standard is DOE-STD-7501-99, The DOE Corporate Lessons Learned Program , December 1999. The following...to avoid recurrence. These defining aspects of the Department of Energy Lessons Learned Program are consistent with aspects of the Center for

  8. Lessons to Be Learned from Past Errors

    MedlinePlus

    ... Store Consulting FAQ Tools About Us Contact Us Lessons to Be Learned from Past Errors The following ... medicines safely General Advice on Safe Medication Use Lessons to Be Learned from Past Errors Preventing Drug ...

  9. Hiligaynon Lessons. PALI Language Texts: Philippines.

    ERIC Educational Resources Information Center

    Motus, Cecile L.

    A collection of 54 lessons in Hiligaynon, one of the major languages of the Philippines, is divided into 12 units, each lesson intended for about 4 to 5 hours of classroom instruction. A brief grammar summary introduces each unit. A structural content note begins each lesson within the units, followed by microdialogues (two to four lines)…

  10. Lessons from 30 Years of Flight Software

    NASA Technical Reports Server (NTRS)

    McComas, David C.

    2015-01-01

    This presentation takes a brief historical look at flight software over the past 30 years, extracts lessons learned and shows how many of the lessons learned are embodied in the Flight Software product line called the core Flight System (cFS). It also captures the lessons learned from developing and applying the cFS.

  11. What Happens at the Lesson Start?

    ERIC Educational Resources Information Center

    Saloviita, Timo

    2016-01-01

    Transitional periods, such as lesson starts, are necessary steps from one activity to another, but they also compete with time for actual learning. The aim of the present study was to replicate a previous pilot study on lesson starts and explore possible disturbances. In total, 130 lesson starts in Finnish basic education in grades 1-9 were…

  12. Revisiting the Great Lessons. Spotlight: Cosmic Education.

    ERIC Educational Resources Information Center

    Chattin-McNichols, John

    2002-01-01

    Considers the role of the Great Lessons--formation of the universe, evolution of life, evolution of humans, and discovery of language and mathematics--in the Montessori elementary curriculum. Discusses how the Great Lessons guide and organize the curriculum, as well as the timing of the lessons across the 6-12 age span. (JPB)

  13. Sharing lessons learned - what have we learned?

    SciTech Connect

    Bickford, J.C., Westinghouse Hanford, Richland, WA

    1997-11-26

    A set of viewgraphs for presenting what has been learned from experience with the Department of Energy`s Lessons Learned program, covering a brief history, the system and tools for sharing and accessing Lessons Learned, and how Lessons Learned can help the audience.

  14. Revisiting the Great Lessons. Spotlight: Cosmic Education.

    ERIC Educational Resources Information Center

    Chattin-McNichols, John

    2002-01-01

    Considers the role of the Great Lessons--formation of the universe, evolution of life, evolution of humans, and discovery of language and mathematics--in the Montessori elementary curriculum. Discusses how the Great Lessons guide and organize the curriculum, as well as the timing of the lessons across the 6-12 age span. (JPB)

  15. Human Rights and China. Lesson Units.

    ERIC Educational Resources Information Center

    Holmes, Stanley T.

    This curriculum unit presents lessons based on information and ideas gained from a 1994 Fulbright-Hays Summer Seminar Abroad Program in the People's Republic of China. This series of three lessons is created as an introduction to Model United Nations types of activities for high school students. Lesson 1, "What are Human Rights?" deals…

  16. Holiday Market Basket Information. Lesson Plan.

    ERIC Educational Resources Information Center

    McNamara, Jeanne

    This lesson plan involves the calculation of a price index using a fictitious market basket for holiday celebrations. The lesson plan provides a content objective; cites an economic standard; gives background information; lists materials needed; details the lesson agenda; and suggests closure. Attached are a "12 Days of Christmas Gifts' Price…

  17. The Impeachment of Andrew Johnson. Web Lesson.

    ERIC Educational Resources Information Center

    Constitutional Rights Foundation, Los Angeles, CA.

    This lesson presents the historical background of Abraham Lincoln's selection of Andrew Johnson as his running mate in the election of 1864. The lesson considers the climate in the U.S. Congress after President Lincoln's assassination. The details of the impeachment and trial of President Andrew Johnson are given. The lesson presents three…

  18. Hiligaynon Lessons. PALI Language Texts: Philippines.

    ERIC Educational Resources Information Center

    Motus, Cecile L.

    A collection of 54 lessons in Hiligaynon, one of the major languages of the Philippines, is divided into 12 units, each lesson intended for about 4 to 5 hours of classroom instruction. A brief grammar summary introduces each unit. A structural content note begins each lesson within the units, followed by microdialogues (two to four lines)…

  19. Legacy: Challenging Lessons in Civics and Citizenship.

    ERIC Educational Resources Information Center

    Hardin, Julia P., Ed.

    This is a collection of lesson plans on civic education designed for all levels of gifted students and written by teachers from across the U.S. The 25 teachers submitting lessons to the compilation are a part of the LEGACY (Linking Educators and the Gifted with Attorneys for Civics: Yes!) project. The lessons involve students in the study of the…

  20. More than Tolerance for Engineering Lessons

    ERIC Educational Resources Information Center

    Burrows, Andrea; Herfat, Safa; Truesdell, Pam; Miller, Richard

    2013-01-01

    Described herein is a science, mathematics, engineering, and technology (STEM) secondary lesson created by graduate engineering student Safa Herfat, with modifications by her co-authors. The lessons learned from this case study are explored through an explanation of tolerance, a description of the lesson, the results obtained, and participant…