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Sample records for observation period suggesting

  1. HR 1225 - New observations and period search

    NASA Astrophysics Data System (ADS)

    DuPuy, D. L.; Collins, G.; Swingler, D. N.

    1982-02-01

    Four nights of photoelectric observations of the delta Scuti star HR 1225 have been obtained. The light curve has a variable amplitude envelope indicating that more than one period is present. A search for periodicities using the Jurkevich method and Fourier analysis suggests periods of 0.156 d and 0.097 d. A least-squares solution yields a fair fit to the data with these two periods. The Fourier transform suggests that three periods are present.

  2. Some Suggestions for Writing up Asteroid Lightcurve Observations for Publication

    NASA Astrophysics Data System (ADS)

    Harris, A. W.

    2005-05-01

    Over the years I have spent many hours re-constructing photometric observa- tions from published works that would have been much easier if the authors had provided full and accurate details of the observations being reported. In this paper I will present the essential elements of reporting that render the photometric observations reported most useful and convenient for future analysis. The underlying principle to keep in mind is that the composite lightcurve you construct may not be right, or may not serve the purposes of some future research project, such that someone may need to recover your original observations as a time series rather than just the composite lightcurve presented. Other ancillary information should be provided to assist in using the data in combination with observations at other times, e.g. the aspect data (sky position, phase angle, light time correction if applied, etc.), and the color band and magnitude scale information. In a composite lightcurve figure, vertical (magnitude) offsets applied night to night should be indicated (in the figure or in a data table), days of obser- vation should be plotted with different symbols and identified, and if cov- erage on a single night exceeds the rotation period such that the time series is "wrapped", it should be possible to determine the actual time of obser- vation of each datum. In constructing a composite, it is essential that the period used to fold the data be the exact value stated so that the exact observation times can be reconstructed from the composite. Ideally, all data presented should also be made available in electronic form in a public archive (this will be a topic of considerable discussion at the meeting). Another essential feature is to reference and critically evaluate any pre- vious lightcurves of an object that can be found in the literature. In addi- tion to checking for consistency of results and possibly incorporating other observations in the analysis, the task of

  3. HR 5960 - New observations and period search

    NASA Astrophysics Data System (ADS)

    DuPuy, D. L.; Burgoyne, L. G.

    1983-01-01

    New photoelectric observations of the Delta Scuti star HR 5960 (CL Dra) obtained on nine closely spaced nights are discussed. It is noted that periodicities in the range of 0.06 d to 0.069 d have already been reported for this star. A Jurkevich periodogram analysis and nonlinear least-squares analysis give a primary period of 0.0676 d, with a secondary period of 0.0493 d. There is still some uncertainty whether the primary period is 0.0676 d or 0.0685 d. On the average, 55 observations of the variable were obtained each night, with an average interval of 5.5 minutes between observations. The air mass of the observations varied from 1.06 to 1.3. In all, 492 observations of the variable star were made.

  4. Mars atmosphere pressure periodicities from Viking observations

    NASA Technical Reports Server (NTRS)

    Sharman, R. D.; Ryan, J. A.

    1980-01-01

    The first Martian year of pressure data taken by the Viking landers on Mars is subjected to power spectrum analysis. The analysis suggests that strong periodicities are present in the Martian atmosphere, especially at the high-latitude (48 deg N) site of the second lander. Most of these periodicities are probably due to the passage of baroclinic waves. Inspection of individual segments of data shows that the periodicities of the dominant waves vary significantly with time of year. This may be related to the amount of dust in the atmosphere since the dominant frequencies of the waves during times of major dust storms are quite different than at other times.

  5. Periodic Properties and Inquiry: Student Mental Models Observed during a Periodic Table Puzzle Activity

    ERIC Educational Resources Information Center

    Larson, Kathleen G.; Long, George R.; Briggs, Michael W.

    2012-01-01

    The mental models of both novice and advanced chemistry students were observed while the students performed a periodic table activity. The mental model framework seems to be an effective way of analyzing student behavior during learning activities. The analysis suggests that students do not recognize periodic trends through the examination of…

  6. OBSERVED POLARIZATION OF BROWN DWARFS SUGGESTS LOW SURFACE GRAVITY

    SciTech Connect

    Sengupta, Sujan; Marley, Mark S. E-mail: Mark.S.Marley@NASA.go

    2010-10-20

    Light scattering by atmospheric dust particles is responsible for the polarization observed in some L dwarfs. Whether this polarization arises from an inhomogeneous distribution of dust across the disk or an oblate shape induced by rotation remains unclear. Here, we argue that the latter case is plausible and, for many L dwarfs, the more likely one. Furthermore, evolutionary models of mature field L dwarfs predict surface gravities ranging from about 200 to 2500 m s{sup -2} (corresponding to masses of {approx}15-70 M {sub Jupiter}). Yet comparison of observed spectra to available synthetic spectra often does not permit more precise determination of the surface gravity of individual field L dwarfs, leading to important uncertainties in their properties. Since rotationally induced non-sphericity, which gives rise to non-zero disk-integrated polarization, is more pronounced at lower gravities, polarization is a promising low gravity indicator. Here, we combine a rigorous multiple scattering analysis with a self-consistent cloudy atmospheric model and observationally inferred rotational velocities and find that the observed optical polarization can be explained if the surface gravity of the polarized objects is about 300 m s{sup -2} or less, potentially providing a new method for constraining L dwarf masses.

  7. Multispacecraft observations of quasi-periodic emissions

    NASA Astrophysics Data System (ADS)

    Nemec, Frantisek; Picket, Jolene S.; Santolik, Ondrej

    2014-05-01

    Quasi-periodic (QP) emissions are VLF electromagnetic waves in the frequency range of about 0.5-5 kHz which exhibit a periodic time modulation of the wave intensity. The modulation period is usually on the order of a few tens of seconds. The generation mechanism of these emissions is still not understood, but at least in some cases it appears to be related to ULF magnetic field pulsations which result in periodic modifications of the resonant conditions in the source region. We use multipoint measurements of QP emissions by the 4 Cluster spacecraft. The observations are obtained close to the equatorial region at radial distances of about 4 Earth radii, i.e. close to a possible generation region. A combined analysis of the high resolution data obtained by the WBD instruments and the ULF magnetic field data obtained by the FGM instruments allows for a detailed case-study analysis of these unique emissions. The presented analysis benefits from the recent close-separation configuration of three of the Cluster spacecraft (≡20-100 km) and a related timing analysis, which would be impossible otherwise.

  8. THE PERIOD CHANGE OF THE CEPHEID POLARIS SUGGESTS ENHANCED MASS LOSS

    SciTech Connect

    Neilson, Hilding R.; Langer, Norbert; Engle, Scott G.; Guinan, Ed; Wasatonic, Richard P.; Williams, David B.

    2012-02-15

    Polaris is one of the most observed stars in the night sky, with recorded observations spanning more than 200 years. From these observations, one can study the real-time evolution of Polaris via the secular rate of change of the pulsation period. However, the measurements of the rate of period change do not agree with predictions from state-of-the-art stellar evolution models. We show that this may imply that Polaris is currently losing mass at a rate of M-dot {approx}10{sup -6} M{sub Sun} yr{sup -1} based on the difference between modeled and observed rates of period change, consistent with pulsation-enhanced Cepheid mass loss. A relation between the rate of period change and mass loss has important implications for understanding stellar evolution and pulsation, and provides insight into the current Cepheid mass discrepancy.

  9. Estimating Percent of Time and Rate Via Direct Observation: A Suggested Observational Procedure and Format.

    ERIC Educational Resources Information Center

    Saudargas, Richard A.; Lentz, Frances E., Jr.

    1986-01-01

    Using development of a State Event Observation System as an example, the decision rules and procedures for the constructing of standardized multiple behavior observational systems that provide accurate, reliable data for school-based assessment, intervention, and research are described. Reliability and validity data from the SECOS are provided.…

  10. Lengthened Cutaneous Silent Period in Fibromyalgia Suggesting Central Sensitization as a Pathogenesis

    PubMed Central

    Koo, Yong Seo; Kim, Byung-Jo

    2016-01-01

    The pathogenesis of fibromyalgia (FM) has not been clearly elucidated, but central sensitization, which plays an important role in the development of neuropathic pain, is considered to be the main mechanism. The cutaneous silent period (CSP), which is a spinal reflex mediated by A-delta cutaneous afferents, is useful for the evaluation of sensorimotor integration at the spinal and supraspinal levels. To understand the pathophysiology of FM, we compared CSP patterns between patients with FM and normal healthy subjects. Twenty-four patients with FM diagnosed in accordance with the 1990 American College of Rheumatology classification system and 24 age- and sex-matched healthy volunteers were recruited. The CSP was measured from the abductor pollicis brevis muscle. Demographic data, number of tender points, and visual analog scale and FM impact questionnaire scores were collected. The measured CSP and clinical parameters of the patient and control groups were compared. In addition, possible correlations between the CSP parameters and the other clinical characteristics were analyzed. Mean CSP latencies did not differ between patients (55.50 ± 10.97 ms) and healthy controls (60.23 ± 11.87 ms; p = 0.158), although the mean CSP duration was significantly longer in patients (73.75 ± 15.67 ms) than in controls (63.50 ± 14.05 ms; p = 0.021). CSP variables did not correlate with any clinical variables. The significantly longer CSP duration in FM patients suggests central dysregulation at the spinal and supraspinal levels, rather than peripheral small fiber dysfunction. PMID:26871583

  11. Cumulative dose on fractional delivery of tomotherapy to periodically moving organ: A phantom QA suggestion

    SciTech Connect

    Shin, Eunhyuk; Han, Youngyih; Park, Hee-Chul; Sung Kim, Jin; Hwan Ahn, Sung; Suk Shin, Jung; Gyu Ju, Sang; Ho Choi, Doo; Lee, Jaiki

    2013-01-01

    This study was conducted to evaluate the cumulative dosimetric error that occurs in both target and surrounding normal tissues when treating a moving target in multifractional treatment with tomotherapy. An experiment was devised to measure cumulative error in multifractional treatments delivered to a horseshoe-shaped clinical target volume (CTV) surrounding a cylinder shape of organ at risk (OAR). Treatments differed in jaw size (1.05 vs 2.5 cm), pitch (0.287 vs 0.660), and modulation factor (1.5 vs 2.5), and tumor motion characteristics differing in amplitude (1 to 3 cm), period (3 to 5 second), and regularity (sinusoidal vs irregular) were tested. Treatment plans were delivered to a moving phantom up to 5-times exposure. Dose distribution on central coronal plane from 1 to 5 times exposure was measured with GAFCHROMIC EBT film. Dose differences occurring across 1 to 5 times exposure of treatment and between treatment plans were evaluated by analyzing measurements of gamma index, gamma index histogram, histogram changes, and dose at the center of the OAR. The experiment showed dose distortion due to organ motion increased between multiexposure 1 to 3 times but plateaued and remained constant after 3-times exposure. In addition, although larger motion amplitude and a longer period of motion both increased dosimetric error, the dose at the OAR was more significantly affected by motion amplitude rather than motion period. Irregularity of motion did not contribute significantly to dosimetric error when compared with other motion parameters. Restriction of organ motion to have small amplitude and short motion period together with larger jaw size and small modulation factor (with small pitch) is effective in reducing dosimetric error. Pretreatment measurements for 3-times exposure of treatment to a moving phantom with patient-specific tumor motion would provide a good estimation of the delivered dose distribution.

  12. A numerical algorithm suggested by problems of transport in periodic media - The matrix case.

    NASA Technical Reports Server (NTRS)

    Allen, R. C., Jr.; Burgmeier, J. W.; Mundorff, P.; Wing, G. M.

    1972-01-01

    Extension of Allen and Wing's (1970) previous work on problems of transport in periodic media to the matrix case. A method in the form of a complete set of equations is presented that may be used without any further analytical work by investigators interested in computing solutions to problems of the type the method is designed to handle. All the formulas have been checked out numerically, and their effectiveness is demonstrated by numerical examples.

  13. Surreptitious observation of responses to hypnotically suggested hallucinations: a test of the compliance hypothesis.

    PubMed

    Perugini, E M; Kirsch, I; Allen, S T; Coldwell, E; Meredith, J M; Montgomery, G H; Sheehan, J

    1998-04-01

    Suggestions for arm levitation and for visual, auditory, tactile, and taste hallucinations were administered twice via audiotape to a group of high suggestible students and low suggestible simulators. During one of the administrations, participants were led to believe they were alone, but their behavior was surreptitiously recorded on videotape and observed on a video monitor. During the other administration, they were observed openly by an experimenter who had not been informed about group assignment. When unaware that they were being observed, simulators were significantly less responsive to suggestion and engaged in substantially more role-inappropriate behavior. In contrast, the responsiveness of nonsimulating students was not affected by the presence of an experimenter, and they exhibited little role-inappropriate behavior even when alone. These data indicate that the responses of suggestible individuals reflect internally generated changes in experience and are not due to simple intentional compliance (i.e., faking). PMID:9558807

  14. Optimizing observing sequence design for periodic and non-periodic phenomena : a Bayesian approach

    NASA Technical Reports Server (NTRS)

    Johnston, Mark D.; Knight, Russell

    2005-01-01

    In this paper we report on our progress on addressing these issues. We have developed an approximate expression for the uniformity of phase coverage that can be used when scheduling to assess candidate sample times. We describe the results obtained using this estimator, and compare them with detailed simulations. We describe our progress and plans for integrating optimizing criteria for both periodic and non-periodic observations into a single observation sequence.

  15. Discrete self-oscillation period branches observed in semiconductor superlattices

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Hu, Bambi; Zheng, Zhigang; Li, Zhigang

    2011-04-01

    We investigate the self-sustained current oscillation of a weakly coupled semiconductor superlattice in the dynamical voltage band using a microscopic sequential tunneling model. With the voltage as a control parameter, two types of branches of current oscillation period versus voltage have been observed, which correspond to various oscillation scenarios. The first branch type consists of a series of period branches in accordance with how many charge dipoles need to be created at the emitter side to trigger a dipole-tripole oscillation scenario. For the second branch type, charge dipoles are generated periodically at the emitter, but all of them fail to develop completely and die out, thereby leading to a low-period oscillation scenario without the dipole-tripole process. The bistability between different branches is also observed by voltage up-sweeping and down-sweeping.

  16. Some observations on the periodate oxidation of amino compounds

    PubMed Central

    Clamp, J. R.; Hough, L.

    1966-01-01

    Various aliphatic and aromatic amines are oxidized by sodium metaperiodate and these reactions have been studied quantitatively in acidic, unbuffered and basic media. Significant differences have been observed between the behaviour of aliphatic and aromatic amines. Certain compounds also behaved differently under acidic and basic conditions. These reactions are related to the periodate oxidation of amino acids and, from observations on a number of glycine derivatives, a reaction mechanism is proposed for this process. PMID:4291354

  17. Simultaneous observation of monochromatic and variable period geomagnetic pulsations

    SciTech Connect

    McDiarmid, D.R.; Nielsen, E. )

    1987-05-01

    On February 4, 1983, following a storm sudden commencement, a monochromatic and a variable period pulsation were simultaneously observed by the Scandinavian Twin Auroral Radar Experiment (STARE) and Sweden and Britain Radar Experiment (SABRE) radar systems. Both pulsations differed from previously analyzed examples of their class. The phase of the monochromatic pulsation increased linearly with latitude rather than decreased. Its amplitude remained relatively constant over the latitude interval of linear phase change. The variable period pulsation experienced a change of orientation of its essentially linear polarization diagram in association with a discontinuity of its period. The variable period pulsation was thus manifest in both the toroidal and poloidal components. The results are discussed in terms of recent developments in theoretical pulsation modeling.

  18. Fast and Statistically Optimal Period Search in Uneven Sampled Observations

    NASA Astrophysics Data System (ADS)

    Schwarzenberg-Czerny, A.

    1996-04-01

    The classical methods for searching for a periodicity in uneven sampled observations suffer from a poor match of the model and true signals and/or use of a statistic with poor properties. We present a new method employing periodic orthogonal polynomials to fit the observations and the analysis of variance (ANOVA) statistic to evaluate the quality of the fit. The orthogonal polynomials constitute a flexible and numerically efficient model of the observations. Among all popular statistics, ANOVA has optimum detection properties as the uniformly most powerful test. Our recurrence algorithm for expansion of the observations into the orthogonal polynomials is fast and numerically stable. The expansion is equivalent to an expansion into Fourier series. Aside from its use of an inefficient statistic, the Lomb-Scargle power spectrum can be considered a special case of our method. Tests of our new method on simulated and real light curves of nonsinusoidal pulsators demonstrate its excellent performance. In particular, dramatic improvements are gained in detection sensitivity and in the damping of alias periods.

  19. Observations of Waves with Observed Periods less than the Buoyancy Period in the Winter Polar Mesopause Region

    NASA Astrophysics Data System (ADS)

    Williams, B. P.; Fritts, D. C.

    2009-12-01

    The sodium wind-temperature lidar at the ALOMAR observatory (69N,16E) can measure the sodium density from 85-100km altitude with 150m height and 15 sec time resolution during winter under good conditions. Radial winds and temperatures can be measured with 1-2 m/s and 1-2 K error after averaging to 1 min in time and 1-2 km in altitude. This allows determination of the short period wave spectrum down to 30sec in Na density and 2min in wind and temperature. Preliminary analysis shows a number of oscillations with observed periods that are less than the buoyancy period. We have also observed an oscillation in the height of a strong summertime sodium sporadic layer with 500m amplitude and 45sec period. We will show the short period spectrum for the full high-resolution database and investigate the sources of these oscillations. Some possibilities include Doppler shifting of the intrinsic frequencies, acoustic waves, or advection of horizontal gradients through our lidar beam.

  20. Aerosol classification using EARLINET measurements for an intensive observational period

    NASA Astrophysics Data System (ADS)

    Papagiannopoulos, Nikolaos; Mona, Lucia; Pappalardo, Gelsomina

    2016-04-01

    ACTRIS (Aerosols, Clouds and Trace gases Research Infrastructure Network) organized an intensive observation period during summer 2012. This campaign aimed at the provision of advanced observations of physical and chemical aerosol properties, at the delivery of information about the 3D distribution of European atmospheric aerosols, and at the monitoring of Saharan dust intrusions events. EARLINET (European Aerosol Research Lidar Network) participated in the ACTRIS campaign through the addition of measurements according to the EARLINET schedule as well as daily lidar-profiling measurements around sunset by 11 selected lidar stations for the period from 8 June - 17 July. EARLINET observations during this almost two-month period are used to characterize the optical properties and vertical distribution of long-range transported aerosol over the broader area of Mediterranean basin. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, Angstrom exponents) are shown to vary with location and aerosol type. A methodology based on EARLINET observations of frequently observed aerosol types is used to classify aerosols into seven separate types. The summertime Mediterranean basin is prone to African dust aerosols. Two major dust events were studied. The first episode occurred from the 18 to 21 of the June and the second one lasted from 28 June to 6 July. The lidar ratio within the dust layer was found to be wavelength independent with mean values of 58±14 sr at 355 nm and 57±11 sr at 532 nm. For the particle linear depolarization ratio, mean values of 0.27±0.04 at 532 nm have been found. Acknowledgements. The financial support for EARLINET in the ACTRIS Research Infrastructure Project by the European Union's Horizon 2020 research and innovation programme under grant agreement no. 654169 and previously under grant agreement no. 262254 in the Seventh Framework Programme (FP7/2007-2013) is gratefully acknowledged.

  1. The Search for Periodic Components in Observational Data

    NASA Astrophysics Data System (ADS)

    Baluev, R. V.

    2014-09-01

    This review is devoted to the problem of searching for periodicities in observational data using periodograms based on the general statistical likelihood ratio test and special variants of it, including the classical Lomb-Scargle periodogram. Primary emphasis is on the problem of estimating the statistical significance of the periodicities detected in this manner. We assume that a universal solution of this problem exists involving an effective method in which the periodogram is regarded as a random process (or random field), while an approximation for the required "false alarm probability" is constructed by a generalized Rice method. Besides a unified method for determining the expected noise levels (or significance levels) of these periodograms, we also examine some important special cases with different models of periodic signals (linear and nonlinear). The false alarm probability associated with an observed signal is approximated in most cases by a formula of the type , where z is the observed maximum readout in the periodogram and P is an algebraic polynomial with coefficients that depend on the conditions of the problem. We also examine the problem of separating composite signals with several frequencies from noise. In this case correct analysis of the data requires the use of so-called multifrequency periodograms based on models of signals containing several periodic components. We show that a complete solution to this problem requires construction of 2n-1 such periodograms, where n is the total number of possible frequencies. Finally, we describe some program packages that we have developed which make it easier to perform practical frequency analysis of series using this theory.

  2. Earthquake nucleation mechanisms and periodic loading: Models, Experiments, and Observations

    NASA Astrophysics Data System (ADS)

    Dahmen, K.; Brinkman, B.; Tsekenis, G.; Ben-Zion, Y.; Uhl, J.

    2010-12-01

    The project has two main goals: (a) Improve the understanding of how earthquakes are nucleated ¬ with specific focus on seismic response to periodic stresses (such as tidal or seasonal variations) (b) Use the results of (a) to infer on the possible existence of precursory activity before large earthquakes. A number of mechanisms have been proposed for the nucleation of earthquakes, including frictional nucleation (Dieterich 1987) and fracture (Lockner 1999, Beeler 2003). We study the relation between the observed rates of triggered seismicity, the period and amplitude of cyclic loadings and whether the observed seismic activity in response to periodic stresses can be used to identify the correct nucleation mechanism (or combination of mechanisms). A generalized version of the Ben-Zion and Rice model for disordered fault zones and results from related recent studies on dislocation dynamics and magnetization avalanches in slowly magnetized materials are used in the analysis (Ben-Zion et al. 2010; Dahmen et al. 2009). The analysis makes predictions for the statistics of macroscopic failure events of sheared materials in the presence of added cyclic loading, as a function of the period, amplitude, and noise in the system. The employed tools include analytical methods from statistical physics, the theory of phase transitions, and numerical simulations. The results will be compared to laboratory experiments and observations. References: Beeler, N.M., D.A. Lockner (2003). Why earthquakes correlate weakly with the solid Earth tides: effects of periodic stress on the rate and probability of earthquake occurrence. J. Geophys. Res.-Solid Earth 108, 2391-2407. Ben-Zion, Y. (2008). Collective Behavior of Earthquakes and Faults: Continuum-Discrete Transitions, Evolutionary Changes and Corresponding Dynamic Regimes, Rev. Geophysics, 46, RG4006, doi:10.1029/2008RG000260. Ben-Zion, Y., Dahmen, K. A. and J. T. Uhl (2010). A unifying phase diagram for the dynamics of sheared solids

  3. 313 new asteroid rotation periods from Palomar Transient Factory observations

    SciTech Connect

    Chang, Chan-Kao; Ip, Wing-Huen; Lin, Hsing-Wen; Cheng, Yu-Chi; Ngeow, Chow-Choong; Yang, Ting-Chang; Waszczak, Adam; Kulkarni, Shrinivas R.; Levitan, David; Sesar, Branimir; Prince, Thomas A.; Laher, Russ; Surace, Jason

    2014-06-10

    A new asteroid rotation period survey has been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg{sup 2} in the ecliptic plane, were observed in the R band with a cadence of ∼20 minutes during 2013 February 15-18. We detected 2500 known asteroids with a diameter range of 0.5 km ≤D ≤ 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the 'spin barrier' at ∼2 hr. In contrast to the flat spin-rate distribution of the asteroids with 3 km ≤D ≤ 15 km shown by Pravec et al., our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev day{sup –1}. One superfast rotator candidate and two possible binary asteroids were also found in this work.

  4. A suggestion for quality assessment in systematic reviews of observational studies in nutritional epidemiology

    PubMed Central

    2016-01-01

    OBJECTIVES: It is important to control the quality level of the observational studies in conducting meta-analyses. The Newcastle-Ottawa Scale (NOS) is a representative tool used for this purpose. We investigated the relationship between high-quality (HQ) defined using NOS and the results of subgroup analysis according to study design. METHODS: We selected systematic review studies with meta-analysis which performed a quality evaluation on observational studies of diet and cancer by NOS. HQ determinations and the distribution of study designs were examined. Subgroup analyses according to quality level as defined by the NOS were also extracted. Equivalence was evaluated based on the summary effect size (sES) and 95% confidence intervals computed in the subgroup analysis. RESULTS: The meta-analysis results of the HQ and cohort groups were identical. The overall sES, which was obtained by combining the sES when equivalence was observed between the cohort and case-control groups, also showed equivalence. CONCLUSIONS: The results of this study suggest that it is more reasonable to control for quality level by performing subgroup analysis according to study design rather than by using HQ based on the NOS quality assessment tool. PMID:27156344

  5. The Changing Surface of Saturn's Titan: Cassini Observations Suggest Active Cryovolcanism

    NASA Astrophysics Data System (ADS)

    Nelson, R. M.

    2008-12-01

    conclude that the VIMS instrument has found two instances in which selected regions on Titan's surface became unusually reflective and remained reflective on time scales of days to months. In both cases the area of reflectance variability is large (~100000 sq km), larger than either Loki or the Big Island of Hawaii. This is a strong evidence for currently active surface processes on Titan. Pre-Cassini, Titan was thought of as a pre-biotic earth that was frozen in time. Cassini VIMS and SAR observations combined suggest that Titan is the present day is not frozen solid, and is instead an episodically changing or evolving world. References: [1] Nelson R. M. et al, LPSC 2007 , Europlanets 2007, AGU 2007, EGU 2008, Accepted in Icarus 2008. [2] Lopes et al (this meeting), Stofan et al. Icarus 185, 443-456, 2007. Lopes et al. Icarus 186, 395- 412, 2007. Kirk et al., DPS 2007. Acknowledgement: This work done at JPL under contract with NASA

  6. Periodic variations of oxygen EUV dayglow in the upper atmosphere of Venus: Hisaki/EXCEED observations

    NASA Astrophysics Data System (ADS)

    Masunaga, K.; Seki, K.; Terada, N.; Tsuchiya, F.; Kimura, T.; Yoshioka, K.; Murakami, G.; Yamazaki, A.; Kagitani, M.; Tao, C.; Fedorov, A.; Futaana, Y.; Zhang, T. L.; Shiota, D.; Leblanc, F.; Chaufray, J.-Y.; Yoshikawa, I.

    2015-12-01

    Using the Extreme Ultraviolet Spectroscope for Exospheric Dynamics (EXCEED) aboard Hisaki and the Solar Extreme Ultraviolet Monitor on the Solar and Heliospheric Observatory, we investigate variations of the extreme ultraviolet (EUV) dayglow brightness for OII 83.4 nm, OI 130.4 nm, and OI 135.6 nm in the Venusian upper atmosphere observed in March-April (period 1), April-May (period 2), and June-July (period 3) in 2014. The result shows that characteristic periodicities exist in the dayglow variations other than the ~27 day solar rotational effect of the solar EUV flux: 1.8, 2.8, 3.1, 4.5, and 9.9 day in period 1; 1.1 day in period 2; and 1.0 and 11 day in period 3. Many of these periodicities are consistent with previous observations and theory. We suggest these periodicities are related to density oscillations of oxygen atoms or photoelectrons in the thermosphere. The cause of these periodicities is still uncertain, but planetary-scale waves and/or gravity waves propagating from the middle atmosphere, and/or minor periodic variations of the solar EUV radiation flux may play a role. Effects of the solar wind parameters (velocity, dynamic pressure, and interplanetary magnetic field's intensity) on the dayglow variations are also investigated using the Analyser of Space Plasma and Energetic Atoms (ASPERA-4) and magnetometer aboard Venus Express. Although clear correlation with the dayglow variations is not found, their minor periodicities are similar to the dayglow periodicities. Contribution of the solar wind to the dayglow remains still unknown, but the solar wind parameters might affect the dayglow variations.

  7. HF radar observations of ionospheric backscatter during geomagnetically quiet periods

    NASA Astrophysics Data System (ADS)

    Kane, T. A.; Makarevich, R. A.; Devlin, J. C.

    2012-01-01

    The quiet-time coherent backscatter from the F-region observed by the Tasman International Geospace Environment Radar (TIGER) Bruny Island HF radar is analysed statistically in order to determine typical trends and controlling factors in the ionospheric echo occurrence. A comparison of the F-region peak density values from the IRI-2007 model and ionosonde measurements in the vicinity of the radar's footprint shows a very good agreement, particularly at subauroral and auroral latitudes, and model densities within the radar's footprint are used in the following analyses. The occurrence of F-region backscatter is shown to exhibit distinct diurnal, seasonal and solar cycle variations and these are compared with model trends in the F-region peak electron density and Pedersen conductance of the underlying ionosphere. The solar cycle effects in occurrence are demonstrated to be strong and more complex than a simple proportionality on a year-to-year basis. The diurnal and seasonal effects are strongly coupled to each other, with diurnal trends exhibiting a systematic gradual variation from month to month that can be explained when both electron density and conductance trends are considered. During the night, the echo occurrence is suggested to be controlled directly by the density conditions, with a direct proportionality observed between the occurrence and peak electron density. During the day, the echo occurrence appears to be controlled by both conductance and propagation conditions. It is shown that the range of echo occurrence values is smaller for larger conductances and that the electron density determines what value the echo occurrence takes in that range. These results suggest that the irregularity production rates are significantly reduced by the highly conducting E layer during the day while F-region density effects dominate during the night.

  8. Are Dietary Restraint Scales Valid Measures of Acute Dietary Restriction? Unobtrusive Observational Data Suggest Not

    ERIC Educational Resources Information Center

    Stice, Eric; Fisher, Melissa; Lowe, Michael R.

    2004-01-01

    The finding that dietary restraint scales predict onset of bulimic pathology has been interpreted as suggesting that dieting causes this eating disturbance, despite the dearth of evidence that these scales are valid measures of dietary restriction. The authors conducted 4 studies that tested whether dietary restraint scales were inversely…

  9. The Prosaics of Figurative Language in Preschool: Some Observations and Suggestions for Research

    ERIC Educational Resources Information Center

    Pramling, Niklas; Samuelsson, Ingrid Pramling

    2009-01-01

    In a significant book, Cameron suggested that we study metaphor as "prosaics" (i.e. as a feature of mundane talk). In this article, by means of a few brief examples, we point to instances of such talk in the setting of preschool. We also discuss some opportunities for learning that such talk could offer children, and what the implications for the…

  10. The Prosaics of Figurative Language in Preschool: Some Observations and Suggestions for Research

    ERIC Educational Resources Information Center

    Pramling, Niklas; Samuelsson, Ingrid Pramling

    2007-01-01

    In a significant work, "Metaphor in educational discourse", Cameron has suggested that we study metaphor as "prosaics" (i.e. as a feature of mundane talk). In this paper, by means of some brief examples, we point to instances of such talk in the setting of preschool. We also discuss opportunities for learning that such talk could offer children,…

  11. Inferring Rotation Periods of Young Stars from Synoptic Observations

    NASA Astrophysics Data System (ADS)

    Hartigan, Patrick; Johns-Krull, Christopher M.; Scowen, Paul

    2012-04-01

    Using known distributions for the periods, amplitudes and light-curve shapes of young stars, we examine how well one could measure periods of these objects in the upcoming era of large synoptic surveys. Surveys like the LSST should be able to recover accurate rotation periods for over 90% of targets of interest in regions near to massive-star formation. That information will usher in a new era in our understanding of how the angular momentum of a young star/disk system evolves with time.

  12. Observations by a University Anatomy Teacher and a Suggestion for Curricular Change: Integrative Anatomy for Undergraduates

    ERIC Educational Resources Information Center

    Darda, David M.

    2010-01-01

    The observation that anatomical course offerings have decreased in undergraduate biology curricula is supported by a survey of undergraduate institutions in the state of Washington. This reduction, due partially to increased emphasis in other areas of the biology curriculum, along with the lack of anatomy prerequisites for admission to most…

  13. Periodicity in Attachment Organelle Revealed by Electron Cryotomography Suggests Conformational Changes in Gliding Mechanism of Mycoplasma pneumoniae

    PubMed Central

    Kawamoto, Akihiro; Matsuo, Lisa; Kato, Takayuki; Yamamoto, Hiroki

    2016-01-01

    ABSTRACT Mycoplasma pneumoniae, a pathogenic bacterium, glides on host surfaces using a unique mechanism. It forms an attachment organelle at a cell pole as a protrusion comprised of knoblike surface structures and an internal core. Here, we analyzed the three-dimensional structure of the organelle in detail by electron cryotomography. On the surface, knoblike particles formed a two-dimensional array, albeit with limited regularity. Analyses using a nonbinding mutant and an antibody showed that the knoblike particles correspond to a naplike structure that has been observed by negative-staining electron microscopy and is likely to be formed as a complex of P1 adhesin, the key protein for binding and gliding. The paired thin and thick plates feature a rigid hexagonal lattice and striations with highly variable repeat distances, respectively. The combination of variable and invariant structures in the internal core and the P1 adhesin array on the surface suggest a model in which axial extension and compression of the thick plate along a rigid thin plate is coupled with attachment to and detachment from the substrate during gliding. PMID:27073090

  14. Quasi-periodic pulsations with varying period in multi-wavelength observations of an X-class flare

    SciTech Connect

    Huang, Jing; Tan, Baolin; Zhang, Yin; Karlický, Marian; Mészárosová, Hana

    2014-08-10

    This work presents an interesting phenomenon of the period variation in quasi-periodic pulsations (QPPs) observed during the impulsive phase of a coronal mass ejection-related X1.1 class flare on 2012 July 6. The period of QPPs was changed from 21 s at soft X-rays (SXR) to 22-23 s at microwaves, to ∼24 s at extreme ultraviolet emissions (EUV), and to 27-32 s at metric-decimetric waves. The microwave, EUV, and SXR QPPs, emitted from flare loops of different heights, were oscillating in phase. Fast kink mode oscillations were proposed to be the modulation mechanism, which may exist in a wide region in the solar atmosphere from the chromosphere to the upper corona or even to the interplanetary space. Changed parameters of flare loops through the solar atmosphere could result in the varying period of QPPs at different wavelengths. The first appearing microwave QPPs and quasi-periodic metric-decimetric type III bursts were generated by energetic electrons. This may imply that particle acceleration or magnetic reconnection were located between these two non-thermal emission sources. Thermal QPPs (in SXR and EUV emissions) occurred later than the nonthermal ones, which would suggest a some time for plasma heating or energy dissipation in flare loops during burst processes. At the beginning of flare, a sudden collapse and expansion of two separated flare loop structures occurred simultaneously with the multi-wavelength QPPs. An implosion in the corona, including both collapse and expansion of flare loops, could be a trigger of loop oscillations in a very large region in the solar atmosphere.

  15. NOMADSS Aircraft Observations Suggest Rapid Oxidation of Elemental Mercury in the Subtropical Free Troposphere

    NASA Astrophysics Data System (ADS)

    Shah, V.; Jaegle, L.; Gratz, L.; Ambrose, J. L., II; Jaffe, D. A.

    2014-12-01

    Oxidized mercury species constitute a small fraction of the total atmospheric burden of mercury, but play an important role in the cycling of mercury in the environment. They dominate the deposition flux of mercury from the atmosphere to the Earth's surfaces, because of their high solubility and low vapor pressure. Their primary source is in-situ oxidation of elemental mercury, but our understanding of these oxidation mechanisms is limited. The Nitrogen, Oxidants, Mercury, and Aerosol Distribution, Sources, and Sinks (NOMADSS) experiment was designed with the aim of addressing these limitations, using aircraft-based speicated measurements of mercury in the troposphere over the eastern US in the summer of 2013. We observed high concentrations of oxidized mercury in clean, dry pockets of air originating in the upper troposphere. We analyze these observations with the GEOS-Chem model, which simulates oxidation of mercury by bromine radicals. The modeled concentrations of oxidized mercury are found to be low, by up to a factor of ten, compared to the observations. This indicates that the oxidation rate of mercury is much faster than that calculated in the model. We perform two simulations to test the sensitivity of the modeled oxidation: (i) by increasing bromine radical concentrations by a factor of three in the 45°S-45°N latitude band, and (ii) by using an oxidation rate constant that is higher by a factor of five. We find that the model performance improves considerably in both these simulations. Here, we present a comparison of the standard and the sensitivity simulations to the NOMADSS and the surface-based Mercury Deposition Network (MDN) observations. We further discuss the potential implications of the faster oxidation on the global transport, distribution, and burden of oxidized mercury.

  16. A nutrition and conditioning intervention for natural bodybuilding contest preparation: observations and suggestions.

    PubMed

    Gentil, Paulo

    2015-01-01

    Bodybuilding is full of myths and practices that are contrary to the scientific literature, which can lead to health problems. Adopting a scientifically designed approach is very important, as it may help bodybuilders to achieve better results while preserving their health. However, I have some criticism regarding some practices adopted in the referred article as ad libitum ingestion of sugar-free cordial and flavored tea and the performance of the exercise in fasted state, as it seems to bring no benefit and have some potential problems. Some suggestion are made in order to preserve FFM, like changing training split and exercise selection; increasing carbohydrate ingestion and decreasing protein intake; changing the resistance training stimuli and reducing the volume of aerobic exercises and increase its intensity. PMID:26696792

  17. Statistical Properties of Quasi-Periodic Pulsations in White-Light Flares Observed With Kepler

    NASA Astrophysics Data System (ADS)

    Pugh, C. E.; Armstrong, D. J.; Nakariakov, V. M.; Broomhall, A.-M.

    2016-04-01

    We embark on a study of quasi-periodic pulsations (QPPs) in the decay phase of white-light stellar flares observed by Kepler. Out of the 1439 flares on 216 different stars detected in the short-cadence data using an automated search, 56 flares are found to have pronounced QPP-like signatures in the light curve, of which 11 have stable decaying oscillations. No correlation is found between the QPP period and the stellar temperature, radius, rotation period and surface gravity, suggesting that the QPPs are independent of global stellar parameters. Hence they are likely to be the result of processes occurring in the local environment. There is also no significant correlation between the QPP period and flare energy, however there is evidence that the period scales with the QPP decay time for the Gaussian damping scenario, but not to a significant degree for the exponentially damped case. This same scaling has been observed for MHD oscillations on the Sun, suggesting that they could be the cause of the QPPs in those flares. Scaling laws of the flare energy are also investigated, supporting previous reports of a strong correlation between the flare energy and stellar temperature/radius. A negative correlation between the flare energy and stellar surface gravity is also found.

  18. Statistical properties of quasi-periodic pulsations in white-light flares observed with Kepler

    NASA Astrophysics Data System (ADS)

    Pugh, C. E.; Armstrong, D. J.; Nakariakov, V. M.; Broomhall, A.-M.

    2016-07-01

    We embark on a study of quasi-periodic pulsations (QPPs) in the decay phase of white-light stellar flares observed by Kepler. Out of the 1439 flares on 216 different stars detected in the short-cadence data using an automated search, 56 flares are found to have pronounced QPP-like signatures in the light curve, of which 11 have stable decaying oscillations. No correlation is found between the QPP period and the stellar temperature, radius, rotation period and surface gravity, suggesting that the QPPs are independent of global stellar parameters. Hence they are likely to be the result of processes occurring in the local environment. There is also no significant correlation between the QPP period and flare energy, however there is evidence that the period scales with the QPP decay time for the Gaussian damping scenario, but not to a significant degree for the exponentially damped case. This same scaling has been observed for MHD oscillations on the Sun, suggesting that they could be the cause of the QPPs in those flares. Scaling laws of the flare energy are also investigated, supporting previous reports of a strong correlation between the flare energy and stellar temperature/radius. A negative correlation between the flare energy and stellar surface gravity is also found.

  19. Examining Periodic Solar-Wind Density Structures Observed in the SECCHI Heliospheric Imagers

    NASA Technical Reports Server (NTRS)

    Viall, Nicholeen M.; Spence, Harlan E.; Vourlidas, Angelos; Howard, Russell

    2010-01-01

    We present an analysis of small-scale, periodic, solar-wind density enhancements (length scales as small as approximately equals 1000 Mm) observed in images from the Heliospheric Imager (HI) aboard STEREO-A. We discuss their possible relationship to periodic fluctuations of the proton density that have been identified at 1 AU using in-situ plasma measurements. Specifically, Viall, Kepko, and Spence examined 11 years of in-situ solar-wind density measurements at 1 AU and demonstrated that not only turbulent structures, but also nonturbulent, periodic density structures exist in the solar wind with scale sizes of hundreds to one thousand Mm. In a subsequent paper, Viall, Spence, and Kasper analyzed the alpha-to-proton solar-wind abundance ratio measured during one such event of periodic density structures, demonstrating that the plasma behavior was highly suggestive that either temporally or spatially varying coronal source plasma created those density structures. Large periodic density structures observed at 1 AU, which were generated in the corona, can be observable in coronal and heliospheric white-light images if they possess sufficiently high density contrast. Indeed, we identify such periodic density structures as they enter the HI field of view and follow them as they advect with the solar wind through the images. The smaller, periodic density structures that we identify in the images are comparable in size to the larger structures analyzed in-situ at 1 AU, yielding further evidence that periodic density enhancements are a consequence of coronal activity as the solar wind is formed.

  20. Cybersemiotics: A suggestion for a transdisciplinary framework for description of observing, anticipatory and meaning producing systems

    NASA Astrophysics Data System (ADS)

    Brier, Soren

    1998-07-01

    The ability of systems to be anticipatory seems to be intricate connected with the ability to observe and to cognate by reducing complexity through signification. The semantic capacity of living systems, the cognitive ability to assign meaning to differences perturbating the system's self-organization, seems to be the prerequisite for the phenomenon of communication, language and consciousness. In cybernetics Bateson developed the idea that information is a difference that makes a difference and second order cybernetics developed the concept of organisms as self-organized and self-produced systems (autopoietic) as the prerequisite of life and cognition. The cognitive ability seems to be qualitative different from what so far is computable on any known machine although parts of different aspects of the process can be partly simulated in AI, neutral network and AL. In semiotics the fundamental process of cognition and communication is called semiosis or signification and C. S. Peirce created a special triadic, objective idealistic, pragmatic and evolutionary philosophy to be able to give a fruitful description of the process and its relation to logic and the concept of natural law. Both second order cybernetics and semiotics sees information and meaning as something produced by individual organisms through structural couplings to the environments or other individuals through historical drift and further developed in social communication. Luhmann points out that social communication also only functions through structural couplings which he calls generalized media such as science, art, power, love and money. Peirce talks of the semiotic net as a triadic view of meanings developing through history and in animals through evolution. In accordance with this Wittgenstein points out that signification is created in language games developed in specific life forms. Life forms are the things we do in society such as seducing, commanding and explaining. As animals do not have

  1. Viking magnetic and electric field observations of periodic Pc 1 waves: Pearl pulsations

    SciTech Connect

    Erlandson, R.E.; Anderson, B.J.; Zanetti, L.J.

    1992-10-01

    Pearl pulsations, with an average repetition period of 60 s, were recorded using the magnetic and electric field experiments on the polar-orbiting Viking satellite. The wave event occurred on September 30, 1986, during Viking orbit 1212 at 1030 MLT, from L=3.6 to L=4.1, and at an altitude of 13,500 km. Electron density observations obtained from Viking show that the waves were generated at the plasmapause and at lower amplitudes in the plasmasphere. The wave Poynting flux, calculated using the magnetic and electric field, indicated that the waves generally were propagating downward toward the ionosphere, although upward Poynting fluxes were observed. Clear evidence of upward propagating waves, associated with downward propagating waves reflected at the ionosphere, was not observed. Linear convective growth rates suggest that the anisotropic ions which provide the free energy have a perpendicular temperature around 15 keV. The repetition period, calculated using the measured electron density and magnetic field strength at Viking, is consistent with the double-hop transit time for ion cyclotron waves which propagate along field lines from one hemisphere to the other. However, the absence of upward propagating waves packets implies that the upper limit of the wave ionospheric reflection coefficient is on the order of 10 to 20%. Alternative mechanism for producing the observed repetition are also investigated and include a periodic generation model of pearl pulsations at the ion bounce period. 42 refs., 5 figs., 4 tabs.

  2. Spurious One-Month and One-Year Periods in Visual Observations of Variable Stars

    NASA Astrophysics Data System (ADS)

    Percy, J. R.

    2015-12-01

    Visual observations of variable stars, when time-series analyzed with some algorithms such as DC-DFT in vstar, show spurious periods at or close to one synodic month (29.5306 days), and also at about a year, with an amplitude of typically a few hundredths of a magnitude. The one-year periods have been attributed to the Ceraski effect, which was believed to be a physiological effect of the visual observing process. This paper reports on time-series analysis, using DC-DFT in vstar, of visual observations (and in some cases, V observations) of a large number of stars in the AAVSO International Database, initially to investigate the one-month periods. The results suggest that both the one-month and one-year periods are actually due to aliasing of the stars' very low-frequency variations, though they do not rule out very low-amplitude signals (typically 0.01 to 0.02 magnitude) which may be due to a different process, such as a physiological one. Most or all of these aliasing effects may be avoided by using a different algorithm, which takes explicit account of the window function of the data, and/or by being fully aware of the possible presence of and aliasing by very low-frequency variations.

  3. Large-Scale periodic solar velocities: An observational study

    NASA Technical Reports Server (NTRS)

    Dittmer, P. H.

    1977-01-01

    Observations of large-scale solar velocities were made using the mean field telescope and Babcock magnetograph of the Stanford Solar Observatory. Observations were made in the magnetically insensitive ion line at 5124 A, with light from the center (limb) of the disk right (left) circularly polarized, so that the magnetograph measures the difference in wavelength between center and limb. Computer calculations are made of the wavelength difference produced by global pulsations for spherical harmonics up to second order and of the signal produced by displacing the solar image relative to polarizing optics or diffraction grating.

  4. Recurrence times and periodicities in 4U 1608-52 as observed by Vela 5B

    NASA Technical Reports Server (NTRS)

    Lochner, James C.; Roussel-Dupre, Diane

    1994-01-01

    We report on the Vela 5B 10 year history of the soft X-ray transient 4U 1608-52, and on the characteristics of its soft X-ray outbursts. The Vela 5B satellite observed the four known outbursts in 1975, 1977, and 1979, and four new outbursts in 1970 and 1971, altering the recurrence pattern of outbursts from this source. One of the 1970 outbursts is symmetric in its intensity profile, while the two outbursts in 1971 have short exponential profiles separated by 80 days. Despite suggestive recurrence periods of approximately 85 and approximately 150 days evident in the time intervals between the outbursts, there is no single statistically significant recurrence time on which the outbursts recur consistently. In the 1970 symmetric event, there is evidence for a period of either 4.10 or 5.19 days. Drawing upon the analogy with SU Ursa Majoris dwarf novae, we suggest that the short period is orbital and any longer period would be associated with a precession period of the accretion disk.

  5. Periodic waves in the lower thermosphere observed by OI630 nm airglow images

    NASA Astrophysics Data System (ADS)

    Paulino, I.; Medeiros, A. F.; Vadas, S. L.; Wrasse, C. M.; Takahashi, H.; Buriti, R. A.; Leite, D.; Filgueira, S.; Bageston, J. V.; Sobral, J. H. A.; Gobbi, D.

    2016-02-01

    Periodic wave structures in the thermosphere have been observed at São João do Cariri (geographic coordinates: 36.5° W, 7.4° S; geomagnetic coordinates based on IGRF model to 2015: 35.8° E, 0.48° N) from September 2000 to November 2010 using OI630.0 nm airglow images. During this period, which corresponds to almost one solar cycle, characteristics of 98 waves were studied. Similarities between the characteristics of these events and observations at other places around the world were noted, primarily the spectral parameters. The observed periods were mostly found between 10 and 35 min; horizontal wavelengths ranged from 100 to 200 km, and phase speed from 30 to 180 m s-1. These parameters indicated that some of the waves, presented here, are slightly faster than those observed previously at low and middle latitudes (Indonesia, Carib and Japan), indicating that the characteristics of these waves may change at different places. Most of observed waves have appeared during magnetically quiet nights, and the occurrence of those waves followed the solar activity. Another important characteristic is the quasi-monochromatic periodicity that distinguish them from the single-front medium-scale traveling ionospheric disturbances (MSTIDs) that have been observed previously over the Brazilian region. Moreover, most of the observed waves did not present a phase front parallel to the northeast-southwest direction, which is predicted by the Perkins instability process. It strongly suggests that most of these waves must have had different generation mechanisms from the Perkins instability, which have been pointed out as being a very important mechanism for the generation of MSTIDs in the lower thermosphere.

  6. Distortion of the seismic radiation pattern in a long period band: Absence of clear node observations

    NASA Astrophysics Data System (ADS)

    Sakai, T.; Kumagai, H.

    2015-12-01

    Sakai et al. (2014, 10th ASC) estimated the source amplitudes in a long-period band of 50 - 100 s using broadband seismic records of earthquakes that occurred in the Philippine and Indonesia, and showed that the source amplitudes fell within a constant band against the moment magnitudes (Mw). Long-period waveforms are thought to be less influenced by structural heterogeneities, and the radiation pattern in a long-period band may not be distorted. However, the results of Sakai et al. (2014) suggest that the nodes are not clearly observed in the long-period band. In this study, we analyzed seismic data from the Japan broadband seismograph network (F-net), which is denser than the networks in the Philippine and Indonesia, and carried out numerical tests using synthetic waveforms to investigate the characteristics of long-period wavefields. We used earthquakes that occurred in Japan with Mw between 4 and 8 since 2003, and estimated their source amplitudes in a long-period band of 50 - 100 s using waveform data from F-net. In each event, we calculated the ratios of the minimum source amplitude to other source amplitudes. We found that the ratios for most of events had values ranging up to roughly 10 regardless of their moment magnitudes and the nodes were also not clearly observed in the F-net data. Using the discrete wavenumber method, we calculated synthetic seismograms assuming uniform station distributions with horizontal intervals of 50 and 100 km as well as the Philippine and F-net station distributions. We assumed an earthquake located in the center of the distributed stations, and systematically changed the dip, strike, and rake angels. We estimated the source amplitudes in the long-period band from the seismograms synthesized with these different fault angles. Our numerical tests indicated that the ratios of the source amplitudes become larger as the density of stations is higher and the ratios depend on the mechanisms. These estimated ratios were larger than

  7. Exclusion of linkage between hypokalemic periodic paralysis and a candidate region in 1q31-32 suggests genetic heterogeneity

    SciTech Connect

    Sillen, A.; Wadelius, C.; Gustabson, K.H.

    1994-09-01

    Familial hypokalemic periodic paralysis (HOKPP) is an autosomal dominant disease with attacks of paralysis of varying severity. The attacks occur at intervals of days to years in otherwise healthy people combined with hypokalemia during attacks. The paralysis attacks are precipitated by a number of different factors, like carbohydrate-rich meals, cold, exercise and mental stress. Recently linkage for HOKPP was shown for chromosome 1q31-32 and the disease was mapped between D1S413 and D1S249. The gene for the calcium channel alfa1-subunit (CACNL 1A3) maps to this interval and in two families no recombination was found between a polymorphism in the CACNL 1A3 gene and the disease. This gene is therefore considered to be a candidate for HOKPP. The analysis of a large Danish family excludes linkage to this region and to the CACNL 1A3 gene. In each direction from D1S413, 18.8 cM could be excluded and for D1S249, 14.9 cM. The present study clearly excludes the possibility that the gene causing HOKPP in a large Danish family is located in the region 1q31-32. This result shows that HOKPP is a heterogenous disease, with only one mapped gene so far.

  8. IMAGING OBSERVATIONS OF QUASI-PERIODIC PULSATIONS IN SOLAR FLARE LOOPS WITH SDO/AIA

    SciTech Connect

    Su, J. T.; Mao, X. J.; Shen, Y. D.; Liu, Y.

    2012-08-20

    Quasi-periodic pulsations (QPPs) of flaring emission with periods from a few seconds to tens of minutes have been widely detected from radio bands to {gamma}-ray emissions. However, in the past the spatial information of pulsations could not be utilized well due to the instrument limits. We report here imaging observations of the QPPs in three loop sections during a C1.7 flare with periods of P = 24 s-3 minutes by means of the extreme-ultraviolet 171 A channel of the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory. We confirm that the QPPs with the shortest period of 24 s were not of an artifact produced by the Nyquist frequency of the AIA 12 s cadence. The QPPs in the three loop sections were interconnected and closely associated with the flare. The detected perturbations propagated along the loops at speeds of 65-200 km s{sup -1}, close to those of acoustic waves in them. The loops were made up of many bright blobs arranged in alternating bright and dark changes in intensity (spatial periodical distribution) with the wavelengths 2.4-5 Mm (as if they were magnetohydrodynamic waves). Furthermore, in the time-distance diagrams, the detected perturbation wavelengths of the QPPs are estimated to be {approx}10 Mm, which evidently do not fit the above ones of the spatial periodic distributions and produce a difference of a factor of 2-4 with them. It is suggested that the short QPPs with periods P < 60 s were possibly sausage-mode oscillations and the long QPPs with periods P > 60 s were the higher (e.g., >2nd) harmonics of slow magnetoacoustic waves.

  9. STEREO observations of quasi-periodically driven high velocity outflows in polar plumes

    NASA Astrophysics Data System (ADS)

    McIntosh, S. W.; Innes, D. E.; de Pontieu, B.; Leamon, R. J.

    2010-02-01

    Context. Plumes are one of the most ubiquitous features seen at the limb in polar coronal holes and are considered to be a source of high density plasma streams to the fast solar wind. Aims: We analyze STEREO observations of plumes and aim to reinterpret and place observations with previous generations of EUV imagers within a new context that was recently developed from Hinode observations. Methods: We exploit the higher signal-to-noise, spatial and temporal resolution of the EUVI telescopes over that of SOHO/EIT to study the temporal variation of polar plumes in high detail. We employ recently developed insight from imaging (and spectral) diagnostics of active region, plage, and quiet Sun plasmas to identify the presence of apparent motions as high-speed upflows in magnetic regions as opposed to previous interpretations of propagating waves. Results: In almost all polar plumes observed at the limb in these STEREO sequences, in all coronal passbands, we observe high speed jets of plasma traveling along the structures with a mean velocity of 135 km s-1 at a range of temperatures from 0.5-1.5 MK. The jets have an apparent brightness enhancement of ~5% above that of the plumes they travel on and repeat quasi-periodically, with repeat-times ranging from five to twenty-five minutes. We also notice a very weak, fine scale, rapidly evolving, but ubiquitous companion of the plumes that covers the entire coronal hole limb. Conclusions: The observed jets are remarkably similar in intensity enhancement, periodicity and velocity to those observed in other magnetic regions of the solar atmosphere. They are multi-thermal in nature. We infer that the jets observed on the plumes are a source of heated mass to the fast solar wind. Further, based on the previous results that motivated this study, we suggest that these jets originated in the upper chromosphere. Five movies are only available in electronic form at http://www.aanda.org

  10. Intrinsic parameters of periodic waves observed in the OI6300 over Brazilian equatorial region

    NASA Astrophysics Data System (ADS)

    Medeiros, Amauri; Buriti, Ricardo; Paulino, Igo; Meriwether, John; Takahashi, Hisao; Maranhão, Glelson

    2016-07-01

    Using two Fabry-Perot interferometers (FPIs) deployed at São João do Cariri (36.5oW, 7.4oS) and Cajazeiras (38.6oW and 6.9oS ) and an all sky imager installed at São João do Cariri, the intrinsic parameters of 23 periodic waves, observed in the OI630.0 nm airglow layer, were estimated and studied. The observed horizontal parameters of these waves were estimated using two-dimensional Fourier analysis. In order to estimate the intrinsic parameters, simultaneous horizontal winds measurements performed by the FPI were used. The results show that the observed parameters of the waves were quite similar to the previous observation, indicating the sources of these waves are not changing along the time. The horizontal wavelengths were mostly found between 90 and 180 km, intrinsic periods ranged from 12 to 36 min and horizontal intrinsic phase speed from 50 to 200 ms-1. Furthermore, the wind was blowing almost perpendicular to the propagation direction of these waves, suggesting that the wind is as important factor to the filtering process of these waves in the lower thermosphere.

  11. Statistical study on magnetotail lobe waves with period 40 - 600 s observed by Cluster

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Zhang, Tielong; Volwerk, Martin

    2016-04-01

    Ultra low frequency (ULF) waves play an important role in energy transport and dissipation in the magnetosphere. In this paper, 263 waves with period 40 - 150 s and 161 waves with period 150 - 600 s in the Earth's magnetotail lobe have been studied by using Cluster data from years 2001 to 2009. Our findings are as follows: (1) 90% of the wave amplitudes with period 40 - 150 s are below ~0.25 nT for transverse components, and ~0.16 nT for compressional component; The amplitudes of longer period waves are somewhat larger; For waves with period 150 - 600 s, 90% of the wave amplitudes are below ~0.36 nT and ~0.39 nT for transverse and compressional components, respectively. (2) Waves within 40 - 150 s prefer to occur in the lobe region close to the plasma sheet, while waves within 150 - 600 s can be observed throughout the lobe region; (3) The amplitudes of lobe waves and AE index are weakly correlated; However, we find that amplitudes tend to be larger when the AE index is larger; (4) Amplitudes also tend to be larger when the solar wind velocity, the solar wind dynamic pressure or its variations (∆PSW) is larger; The correlation coefficient between amplitudes of waves within 150 - 600 s and ∆PSW is up to ~0.58. We suggest that both dynamic pressure in the plasma sheet boundary layer or plasma sheet (inner source) and solar wind conditions (outer source) can contribute to the generation of lobe ULF waves; Waves within 40 - 150 s are effected more by inner source; ∆PSW is more associated with compressional waves within 150 - 600 s than that within 40 - 150 s.

  12. Evaluation of and Suggested Improvements to the WSM6 Microphysics in WRF- ARW Using Synthetic and Observed GOES-13 Imagery

    SciTech Connect

    Grasso, Lewis; Lindsey, Daniel T.; Lim, Kyo-Sun; Clark, Adam; Bikos, Dan; Dembek, Scott R.

    2014-10-01

    Synthetic satellite imagery can be employed to evaluate simulated cloud fields. Past studies have revealed that the Weather Research and Forecasting (WRF) WRF Single-Moment 6-class (WSM6) microphysics in WRF-ARW produces less upper level ice clouds within synthetic images compared to observations. Synthetic Geostationary Operational Environmental Satellite (GOES)-13 imagery at 10.7 μm of simulated cloud fields from the 4 km National Severe Storms Laboratory (NSSL) WRF-ARW is compared to observed GOES-13 imagery. Histograms suggest that too few points contain upper level simulated ice clouds. In particular, side-by-side examples are shown of synthetic and observed convective anvils. Such images illustrate the lack of anvil cloud associated with convection produced by the NSSL WRF-ARW. A vertical profile of simulated hydrometeors suggests that too much cloud water mass may be converted into graupel mass, effectively reducing the main source of ice mass in a simulated anvil. Further, excessive accretion of ice by snow removes ice from an anvil by precipitation settling. Idealized sensitivity tests reveal that a 50% reduction of the conversion of cloud water mass to graupel and a 50% reduction of the accretion rate of ice by snow results in a significant increase in anvil ice of a simulated storm. Such results provide guidance as to which conversions could be reformulated, in a more physical manner, to increase simulated ice mass in the upper troposphere.

  13. Subarcsecond bright points and quasi-periodic upflows below a quiescent filament observed by IRIS

    NASA Astrophysics Data System (ADS)

    Li, T.; Zhang, J.

    2016-05-01

    Context. The new Interface Region Imaging Spectrograph (IRIS) mission provides high-resolution observations of UV spectra and slit-jaw images (SJIs). These data have become available for investigating the dynamic features in the transition region (TR) below the on-disk filaments. Aims: The driver of "counter-streaming" flows along the filament spine is still unknown yet. The magnetic structures and the upflows at the footpoints of the filaments and their relations with the filament mainbody have not been well understood. We study the dynamic evolution at the footpoints of filaments in order to find some clues for solving these questions. Methods: Using UV spectra and SJIs from the IRIS, along with coronal images and magnetograms from the Solar Dynamics Observatory (SDO), we present the new features in a quiescent filament channel: subarcsecond bright points (BPs) and quasi-periodic upflows. Results: The BPs in the TR have a spatial scale of about 350-580 km and lifetimes of more than several tens of minutes. They are located at stronger magnetic structures in the filament channel with a magnetic flux of about 1017-1018 Mx. Quasi-periodic brightenings and upflows are observed in the BPs, and the period is about 4-5 min. The BP and the associated jet-like upflow comprise a "tadpole-shaped" structure. The upflows move along bright filament threads, and their directions are almost parallel to the spine of the filament. The upflows initiated from the BPs with opposite polarity magnetic fields have opposite directions. The velocity of the upflows in the plane of sky is about 5-50 km s-1. The emission line of Si IV 1402.77 Å at the locations of upflows exhibits obvious blueshifts of about 5-30 km s-1, and the line profile is broadened with the width of more than 20 km s-1. Conclusions: The BPs seem to be the bases of filament threads, and the upflows are able to convey mass for the dynamic balance of the filament. The "counter-streaming" flows in previous observations

  14. Subarcsecond bright points and quasi-periodic upflows below a quiescent filament observed by IRIS

    NASA Astrophysics Data System (ADS)

    Li, T.; Zhang, J.

    2016-04-01

    Context. The new Interface Region Imaging Spectrograph (IRIS) mission provides high-resolution observations of UV spectra and slit-jaw images (SJIs). These data have become available for investigating the dynamic features in the transition region (TR) below the on-disk filaments. Aims: The driver of "counter-streaming" flows along the filament spine is still unknown yet. The magnetic structures and the upflows at the footpoints of the filaments and their relations with the filament mainbody have not been well understood. We study the dynamic evolution at the footpoints of filaments in order to find some clues for solving these questions. Methods: Using UV spectra and SJIs from the IRIS, along with coronal images and magnetograms from the Solar Dynamics Observatory (SDO), we present the new features in a quiescent filament channel: subarcsecond bright points (BPs) and quasi-periodic upflows. Results: The BPs in the TR have a spatial scale of about 350-580 km and lifetimes of more than several tens of minutes. They are located at stronger magnetic structures in the filament channel with a magnetic flux of about 1017-1018 Mx. Quasi-periodic brightenings and upflows are observed in the BPs, and the period is about 4-5 min. The BP and the associated jet-like upflow comprise a "tadpole-shaped" structure. The upflows move along bright filament threads, and their directions are almost parallel to the spine of the filament. The upflows initiated from the BPs with opposite polarity magnetic fields have opposite directions. The velocity of the upflows in the plane of sky is about 5-50 km s-1. The emission line of Si IV 1402.77 Å at the locations of upflows exhibits obvious blueshifts of about 5-30 km s-1, and the line profile is broadened with the width of more than 20 km s-1. Conclusions: The BPs seem to be the bases of filament threads, and the upflows are able to convey mass for the dynamic balance of the filament. The "counter-streaming" flows in previous observations

  15. Equatorial planetary waves in the mesosphere observed by airglow periodic oscillations

    NASA Astrophysics Data System (ADS)

    Buriti, R. A.; Takahashi, H.; Lima, L. M.; Medeiros, A. F.

    Planetary scale waves in the equatorial upper mesosphere were studied by measuring the airglow OI557.7 nm, O 2b(0,1) and OH(6,2) emission intensities and OH rotational temperature at São João do Cariri (7.4°S; 36.5°W). From four years of data, 1998-2001, periodic oscillations of the airglow emissions were analyzed using the Lomb-Scargle spectral analysis. An oscillation of 3-4 days was frequently observed, which might be ultra-fast Kelvin waves. No seasonal dependency of the wave activity was found. On some occasions we found a quasi-5-day oscillation with a phase difference between the emissions, suggesting an upward energy flow. This is interpreted as a normal mode Rossby wave.

  16. An international observational study suggests that artificial intelligence for clinical decision support optimizes anemia management in hemodialysis patients.

    PubMed

    Barbieri, Carlo; Molina, Manuel; Ponce, Pedro; Tothova, Monika; Cattinelli, Isabella; Ion Titapiccolo, Jasmine; Mari, Flavio; Amato, Claudia; Leipold, Frank; Wehmeyer, Wolfgang; Stuard, Stefano; Stopper, Andrea; Canaud, Bernard

    2016-08-01

    Managing anemia in hemodialysis patients can be challenging because of competing therapeutic targets and individual variability. Because therapy recommendations provided by a decision support system can benefit both patients and doctors, we evaluated the impact of an artificial intelligence decision support system, the Anemia Control Model (ACM), on anemia outcomes. Based on patient profiles, the ACM was built to recommend suitable erythropoietic-stimulating agent doses. Our retrospective study consisted of a 12-month control phase (standard anemia care), followed by a 12-month observation phase (ACM-guided care) encompassing 752 patients undergoing hemodialysis therapy in 3 NephroCare clinics located in separate countries. The percentage of hemoglobin values on target, the median darbepoetin dose, and individual hemoglobin fluctuation (estimated from the intrapatient hemoglobin standard deviation) were deemed primary outcomes. In the observation phase, median darbepoetin consumption significantly decreased from 0.63 to 0.46 μg/kg/month, whereas on-target hemoglobin values significantly increased from 70.6% to 76.6%, reaching 83.2% when the ACM suggestions were implemented. Moreover, ACM introduction led to a significant decrease in hemoglobin fluctuation (intrapatient standard deviation decreased from 0.95 g/dl to 0.83 g/dl). Thus, ACM support helped improve anemia outcomes of hemodialysis patients, minimizing erythropoietic-stimulating agent use with the potential to reduce the cost of treatment. PMID:27262365

  17. Archive of observations of periodic comet Crommelin made during its 1983-84 apparition

    NASA Technical Reports Server (NTRS)

    Sekanina, Z. (Editor); Aronsson, M.

    1985-01-01

    This is an archive of 680 reduced observations of Periodic Comet Crommelin made during its 1984 apparition. The archive integrates reports by members of the eight networks of the International Halley Watch (IHW) and presents the results of a trial run designed to test the preparedness of the IHW organization for the current apparition of Periodic Comet Halley.

  18. Observations of deep long-period (DLP) seismic events beneath Aleutian arc volcanoes; 1989-2002

    USGS Publications Warehouse

    Power, J.A.; Stihler, S.D.; White, R.A.; Moran, S.C.

    2004-01-01

    Between October 12, 1989 and December 31, 2002, the Alaska Volcano Observatory (AVO) located 162 deep long-period (DLP) events beneath 11 volcanic centers in the Aleutian arc. These events generally occur at mid- to lower-crustal depths (10-45 km) and are characterized by emergent phases, extended codas, and a strong spectral peak between 1.0 and 3.0 Hz. Observed wave velocities and particle motions indicate that the dominant phases are P- and S-waves. DLP epicenters often extend over broad areas (5-20 km) surrounding the active volcanoes. The average reduced displacement of Aleutian DLPs is 26.5 cm2 and the largest event has a reduced displacement of 589 cm2 (or ML 2.5). Aleutian DLP events occur both as solitary events and as sequences of events with several occurring over a period of 1-30 min. Within the sequences, individual DLPs are often separated by lower-amplitude volcanic tremor with a similar spectral character. Occasionally, volcano-tectonic earthquakes that locate at similar depths are contained within the DLP sequences. At most, Aleutian volcanoes DLPs appear to loosely surround the main volcanic vent and occur as part of background seismicity. A likely explanation is that they reflect a relatively steady-state process of magma ascent over broad areas in the lower and middle portions of the crust. At Mount Spurr, DLP seismicity was initiated by the 1992 eruptions and then slowly declined until 1997. At Shishaldin Volcano, a short-lived increase in DLP seismicity occurred about 10 months prior to the April 19, 1999 eruption. These observations suggest a link between eruptive activity and magma flux in the mid- to lower-crust and uppermost mantle.

  19. Observation of flow processes in the vadose zone using ERT on different space and time scales: results, obstacles, and suggestions

    NASA Astrophysics Data System (ADS)

    Noell, Ursula; Ganz, Christina; Lamparter, Axel; Duijnisveld, Wilhelmus; Bachmann, Jörg

    2013-04-01

    deteriorates with depth. The resolution depends on the electrode distances and the depth resolution can be increased by using borehole electrodes. However, if one ha of land is to be observed with a reasonable number of electrodes (some 100) the resolution will be some 10 m. The structures, however, that influence the infiltration process, might be much smaller. Therefore, it is suggested to use ERT as the tool to observe and quantify the infiltration process with regard to time and space on a scale of some meters. For independent proof local TDR devices should be inserted within the investigated area for calibration. These results should then be used to establish a physical soil model that grasps the observed process correctly in time and space. The next step would then be to repeat these local measurements at different locations where the similarity of the processes is at doubt. Only when this is confirmed or discarded, further upscaling steps can be done reliably.

  20. Periodic Crossings of Saturn's Current Sheet by Cassini: Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Khurana, K. K.; Arridge, C. S.; Dougherty, M. K.; Russell, C. T.

    2006-12-01

    Cassini continues to provide exciting new observations from the magnetosphere of Saturn. These observations are helping us understand the structure and dynamics of this rotationally dominant magnetosphere. One of the puzzling observations from the latest magnetotail passes is the occurrence of periodic current sheet crossings in a magnetosphere known for its almost axis-symmetric magnetic field. In these crossings, the radial and azimuthal components of the magnetic field reverse sign twice during a spin period of Saturn in a manner similar to the dipole tilt induced motions of the Jovian current sheet. As the dipole tilt of Saturn's magnetic field is less than 0.2 degree, it is not clear how the current sheet can flap up and down over the spacecraft when it is located quite far from the nominal location of the current sheet. In this presentation, we will examine all of the data so far collected by Cassini to catalogue all of the periodic current sheet crossings in the data. We will examine parameters like the radial distance, latitude, longitude and local time of the spacecraft to understand under what conditions the current sheet crossings are observed. We comment on the relationship between these periodic current sheet crossings to periodicities in the quasi- dipolar region of the magnetosphere. Finally, we will explore models of Saturn's current sheet that can explain the periodicities of the observed magnetic field.

  1. Observations and Light Curve Solutions of Four Ultrashort-Period Binaries

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, D.; Popov, V.; Vasileva, D.; Petrov, N.

    2016-03-01

    The paper presents light curve solutions of our observations of four new ultrashort-period eclipsing binaries with MS components. Two of them have periods almost at the upper limit (0.22 days) of the ultrashort-period binaries, while the periods of around 0.18 days of CSS J171508.5+350658 and CSS J214633.8+120016 are amongst the shortest known orbital periods. CSS J171410.0+445850, CSS J214633.8+120016 and CSS J224326.0+154532 are overcontact binaries with fillout factors around 0.25 while CSS J171508.5+350658 is a semidetached system. The two targets with shortest periods consist of M dwarfs.

  2. Observations and Light Curve Solutions of Four Ultrashort-Period Binaries

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, D.; Popov, V.; Vasileva, D.; Petrov, N.

    2016-06-01

    The paper presents light curve solutions of our observations of four new ultrashort-period eclipsing binaries with MS components. Two of them have periods almost at the upper limit (0.22 days) of the ultrashort-period binaries, while the periods of around 0.18 days of CSS J171508.5+350658 and CSS J214633.8+120016 are amongst the shortest known orbital periods. CSS J171410.0+445850, CSS J214633.8+120016 and CSS J224326.0+154532 are overcontact binaries with fillout factors around 0.25 while CSS J171508.5+350658 is a semidetached system. The two targets with shortest periods consist of M dwarfs.

  3. Solar wind plasma periodicities observed at 1 AU by IMP 8

    NASA Technical Reports Server (NTRS)

    Paularena, K. I.; Szabo, A.; Lazarus, A. J.

    1995-01-01

    The IMP 8 spacecraft has been in Earth orbit since 1973, gathering plasma data over one complete 22-year solar cycle. These data are being examined to look for periodicities at time scales ranging from several hours to the entire span of the data set. A 1.3-year periodicity in the radial speed observed by IMP 8 and Voyager 2 has already been reported for the years from 1987 to 1993. The periodogram method, useful for unevenly sampled data such as the IMP 8 plasma data, has been used to search for other periods. It is interesting to note that the 13-year period is not present in the out-of-the-ecliptic component of the velocity (Vz), although a 1-year period is very obvious both visually and on the periodogram. Both components show a very strong peak associated with the 11-year solar cycle variation. This work will be extended to the thermal speed (a measure of the wind's temperature) and density, although the frequent correlations between these parameters and the velocity are expected to cause similar results. Additionally, the fine resolution data will be examined for shorter time periods than are visible using the hourly average data which are appropriate for longer periods. A comparison with periods observed at other spacecraft may also be made.

  4. Ionospheric variations in the period range of days to tens of days deduced from HF Doppler observation

    NASA Astrophysics Data System (ADS)

    Shibata, Takashi; Yoshimura, Yasuo; Okuzawa, Takashi; Ogawa, Toshio

    Ionospheric variations in the period range of a few days to tens of days observed by the HF Doppler (HFD) method for the entire year of 1986 have been investigated by a spectrum analysis. The crystal oscillator employed has a stability of up 5 x 10 to the -9th/day at the primary stage of 5 MHz. The present method was shown to be capable of detecting ionospheric variations in the period range of both 3 to about 13 days and 16 to about 21 days. It is suggested that a 27-day period was not observed in both the HFD and the foF2 spectra due to minimum solar activity.

  5. Estimating the Period and Q of the Chandler Wobble from Observations and Models of its Excitation

    NASA Astrophysics Data System (ADS)

    Gross, R. S.; Nastula, J.

    2014-12-01

    Any irregularly shaped solid body rotating about some axis that is not aligned with its figure axis will freely wobble as it rotates. For the Earth, this free wobble is known as the Chandler wobble in honor of S. C. Chandler, Jr. who first observed it in 1891. Unlike the forced wobbles of the Earth, such as the annual wobble, whose periods are the same as the periods of the forcing mechanisms, the period of the free Chandler wobble is a function of the internal structure and rheology of the Earth, and its decay time constant, or quality factor Q, is a function of the dissipation mechanism(s), like mantle anelasticity, that are acting to dampen it. Improved estimates of the period and Q of the Chandler wobble can therefore be used to improve our understanding of these properties of the Earth. Here, estimates of the period and Q of the Chandler wobble are obtained by finding those values that minimize the power within the Chandler band of the difference between observed and modeled polar motion excitation spanning 1962-2010. Atmosphere, ocean, and hydrology models are used to model the excitation caused by both mass and motion variations within these global geophysical fluids. Direct observations of the excitation caused by mass variations as determined from GRACE time varying gravitational field measurements are also used. The resulting estimates of the period and Q of the Chandler wobble will be presented along with a discussion of the robustness of the estimates.

  6. High latitude artificial periodic irregularity observations with the upgraded EISCAT heating facility

    NASA Astrophysics Data System (ADS)

    Vierinen, Juha; Kero, Antti; Rietveld, Michael T.

    2013-12-01

    We present a recently developed ionospheric modification experiment that produces artificial periodic irregularities in the ionosphere and uses them to make observations of the spatiotemporal behaviour of the irregularities. In addition, the method can be used to measure Faraday rotation and vertical velocities. We also introduce a novel experiment that allows monitoring the formation of the irregularities during heating, in addition to observing their decay after heating. The first measurements indicate, contrary to existing theory, that the amplitude of the radar echoes from the periodic irregularities grows faster than they decay. We focus on the API effects in the D- and E-region of the ionosphere.

  7. Moroccan speleothem and tree ring records suggest a variable positive state of the North Atlantic Oscillation during the Medieval Warm Period

    NASA Astrophysics Data System (ADS)

    Wassenburg, J. A.; Immenhauser, A.; Richter, D. K.; Niedermayr, A.; Riechelmann, S.; Fietzke, J.; Scholz, D.; Jochum, K. P.; Fohlmeister, J.; Schröder-Ritzrau, A.; Sabaoui, A.; Riechelmann, D. F. C.; Schneider, L.; Esper, J.

    2013-08-01

    We present a magnesium (Mg) and strontium (Sr) record from an aragonitic speleothem (Grotte de Piste, Morocco, 34‬°N; 04°W) providing a reconstruction of effective rainfall from 619 to 1962 AD. The corresponding drip site was monitored over 2 yr for drip water Mg/Ca and Sr/Ca ratios. Results show evidence for prior aragonite precipitation, which can explain negative correlations between speleothem Mg and Sr concentrations. The data shown here have important climate implications concerning the evolution of the North Atlantic Oscillation (NAO). A comparison of the stalagmite data from Grotte de Piste with an updated tree ring based drought reconstruction from Morocco and other NAO related proxy records confirms that the Medieval Warm Period (MWP) was dominated by NAO+ conditions. The stalagmite record and multiple proxy records from the Iberian Peninsula, however, suggest that considerable rainfall variability occurred during the MWP. This implies that the NAO has been more variable during the MWP than formerly suggested.

  8. Observed temporal evolution of global mean age of stratospheric air for the 2002 to 2010 period

    NASA Astrophysics Data System (ADS)

    Stiller, G. P.; von Clarmann, T.; Haenel, F.; Funke, B.; Glatthor, N.; Grabowski, U.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; López-Puertas, M.

    2012-04-01

    An extensive observational data set from MIPAS measurements, consisting of more than one million SF6 vertical profiles distributed globally has been condensed into monthly zonal means of mean age of air for the period September 2002 to January 2010, binned at 10° latitude and 1-2 km altitude. The data were analysed with respect to their temporal variation by fitting a regression model consisting of: a constant and a linear increase term, 2 proxies for the QBO variation, sinusoidal terms for the seasonal and semi-annual variation and overtones for the correction of the shapes to the observed data set. The impact of subsidence of mesospheric SF6-depleted air and in-mixing into non-polar latitudes on mid-latitudinal age of air and its linear increase was assessed and found to be small. The linear increase of mean age of stratospheric air was found to be positive and partly larger than the trend derived by Engel et al. (2009) for most of the Northern mid-latitudes, the middle stratosphere in the tropics, and parts of the Southern mid-latitudes, as well as for the Southern polar upper stratosphere. Multi-year decrease of age of air was found for the lowermost and the upper stratospheric tropics, for parts of Southern mid-latitudes, and for the Northern polar regions. Analyses of the amplitudes and phases of the seasonal variation shed light on the coupling between different stratospheric regions. In particular, the Northern mid-latitude stratosphere is well coupled to the tropics, while the Northern lowermost mid-latitudinal stratosphere is decoupled, confirming the separation of the shallow branch of the Brewer-Dobson circulation from the deep branch. We suggest an overall increased tropical upwelling, together with a weakening of mixing barriers, especially in the Northern hemisphere, as possible explanations for the observed patterns. Reference: Engel, A., Möbius, T., Bönisch, H., Schmidt, U., Heinz, R., Levin, I., Atlas, E., Aoki, S., Nakazawa, T., Sugawara, S

  9. Experimental Observation of a Periodically Oscillating Plasma Sphere in a Gridded Inertial Electrostatic Confinement Device

    SciTech Connect

    Park, J.; Nebel, R.A.; Stange, S.; Murali, S. Krupakar

    2005-07-01

    The periodically oscillating plasma sphere (POPS) [D. C. Barnes and R. A. Nebel, Phys. Plasmas 5, 2498 (1998).] oscillation has been observed in a gridded inertial electrostatic confinement device. In these experiments, ions in the virtual cathode exhibit resonant behavior when driven at the POPS frequency. Excellent agreement between the observed POPS resonance frequency and theoretical predictions has been observed for a wide range of potential well depths and for three different ion species. The results provide the first experimental validation of the POPS concept proposed by Barnes and Nebel [R. A. Nebel and D. C. Barnes, Fusion Technol. 34, 28 (1998).].

  10. Quasi-periodic emissions and related electron precipitation observed by the low-altitude DEMETER spacecraft

    NASA Astrophysics Data System (ADS)

    Hayosh, M.; Nemec, F.; Pasmanik, D.; Santolik, O.; Demekhov, A. G.; Parrot, M.; Titova, L.

    2012-12-01

    We present a survey of quasi-periodic (QP) ELF/VLF emissions detected on board the DEMETER satellite (altitude of about 700 km, nearly Sun-synchronous orbit at 10:30/22:30 LT). Three years of data have been visually inspected for the presence of QP emissions. It is found that QP events occur in about 3 percents of daytime half-orbits, while they are basically absent during the night (note that we were likely to miss QP events with the modulation periods lower than about 10 s or the frequency bandwidth lower than about 400 Hz). The events occur predominantly during quiet geomagnetic conditions following the periods of enhanced geomagnetic activity. Their occurrence and properties are systematically analyzed. Three events with a simultaneous periodic modulation of wave intensity and energetic electron precipitation were analyzed in detail. All events are observed at quiet geomagnetic conditions. Most probably, they are not associated with geomagnetic pulsations. Energetic electron flux data measured by the NOAA-17 satellite are used to supplement DEMETER data in order to determine the spatial and temporal extent of the observed energetic electron precipitation events. Based on the observed correlation between bursts of wave intensity and energetic electron flux we estimate the location and the spatial extent of the source region of QP emissions.

  11. EVOLUTIONARY TRACKS OF TRAPPED, ACCRETING PROTOPLANETS: THE ORIGIN OF THE OBSERVED MASS-PERIOD RELATION

    SciTech Connect

    Hasegawa, Yasuhiro; Pudritz, Ralph E. E-mail: pudritz@physics.mcmaster.ca

    2012-12-01

    The large number of observed exoplanets ({approx}>700) provides important constraints on their origin as deduced from the mass-period diagram of planets. The most surprising features in the diagram are (1) the (apparent) pileup of gas giants at a period of {approx}500 days ({approx}1 AU) and (2) the so-called mass-period relation, which indicates that planetary mass is an increasing function of orbital period. We construct the evolutionary tracks of growing planets at planet traps in evolving protoplanetary disks and show that they provide a good physical understanding of how these observational properties arise. The fundamental feature of our model is that inhomogeneities in protoplanetary disks give rise to multiple (up to 3) trapping sites for rapid (type I) planetary migration of planetary cores. The viscous evolution of disks results in the slow radial movement of the traps and their cores from large to small orbital periods. In our model, the slow inward motion of planet traps is coupled with the standard core accretion scenario for planetary growth. As planets grow, type II migration takes over. Planet growth and radial movement are ultimately stalled by the dispersal of gas disks via photoevaporation. Our model makes a number of important predictions: that distinct sub-populations of planets that reflect the properties of planet traps where they have grown result in the mass-period relation, that the presence of these sub-populations naturally explains a pileup of planets at {approx}1 AU, and that evolutionary tracks from the ice line do put planets at short periods and fill an earlier claimed {sup p}lanet desert{sup -}a sparse population of planets in the mass-semimajor axis diagram.

  12. Local Scale Radiobrightness Modelling during Intensive Observing Period-4 of the Cold Land Processes Experiment-1

    NASA Technical Reports Server (NTRS)

    Kim, Edward J.; Tedesco, Marco; deRoo, Roger; England, Anthony W.; Gu, Haoyu; Pham, Hanh; Boprie, David; Graf, Tobias; Koike, Toshio; Armstrong, Richard

    2004-01-01

    The NASA Cold Land Processes Field Experiment (CLPX-1) was designed to provide microwave remote sensing observations and ground truth for studies of snow and frozen ground remote sensing, particularly issues related to scaling. CLPX-1 was conducted in the spring of 2003 in Colorado, USA. Initial forward model validation work is concentrating on the Local-Scale Observation Site (LSOS), a 0.8 ha study site consisting of open meadows separated by trees where the most detailed measurements were made of snow depth and temperature, density, and grain size profiles. This paper will focus on the ability of forward Dense Medium Radiative Transfer (DMRT) modelling, combined with snowpack measurements to reproduce the radiobrightness signatures observed by the University of Michigan s Truck-Mounted Radiometer System at 19 and 37 GHz during the 4th Intensive Observing Period (IOP4) in March, 2003. Unlike the earlier IOP3, conditions during IOP4 include both wet and dry periods, providing a valuable test of DMRT model performance. Observations of upwelling and downwelling tree radiobrightness will be used to formulate a simple model for the effect of trees within the field of view. In addition, a comparison will be made for the one day of coincident observations by the University of Tokyo s Ground- Based Microwave Radiometer-7 (GBMR-7). These analyses will help guide the choice of future snow retrieval algorithms and the design of future Cold Lands observing systems.

  13. Is Compton Cooling Sufficient to Explain Evolution of Observed Quasi-periodic Oscillations in Outburst Sources?

    NASA Astrophysics Data System (ADS)

    Mondal, Santanu; Chakrabarti, Sandip K.; Debnath, Dipak

    2015-01-01

    In outburst sources, quasi-periodic oscillation (QPO) frequency is known to evolve in a certain way: in the rising phase, it monotonically goes up until a soft intermediate state is achieved. In the propagating oscillatory shock model, oscillation of the Compton cloud is thought to cause QPOs. Thus, in order to increase QPO frequency, the Compton cloud must collapse steadily in the rising phase. In decline phases, the exact opposite should be true. We investigate cause of this evolution of the Compton cloud. The same viscosity parameter that increases the Keplerian disk rate also moves the inner edge of the Keplerian component, thereby reducing the size of the Compton cloud and reducing the cooling timescale. We show that cooling of the Compton cloud by inverse Comptonization is enough for it to collapse sufficiently so as to explain the QPO evolution. In the two-component advective flow configuration of Chakrabarti-Titarchuk, centrifugal force-induced shock represents the boundary of the Compton cloud. We take the rising phase of 2010 outburst of Galactic black hole candidate H 1743-322 and find an estimation of variation of the α parameter of the sub-Keplerian flow to be monotonically rising from 0.0001 to 0.02, well within the range suggested by magnetorotational instability. We also estimate the inward velocity of the Compton cloud to be a few meters per second, which is comparable to what is found in several earlier studies of our group by empirically fitting the shock locations with the time of observations.

  14. IS COMPTON COOLING SUFFICIENT TO EXPLAIN EVOLUTION OF OBSERVED QUASI-PERIODIC OSCILLATIONS IN OUTBURST SOURCES?

    SciTech Connect

    Mondal, Santanu; Chakrabarti, Sandip K.; Debnath, Dipak E-mail: chakraba@bose.res.in

    2015-01-01

    In outburst sources, quasi-periodic oscillation (QPO) frequency is known to evolve in a certain way: in the rising phase, it monotonically goes up until a soft intermediate state is achieved. In the propagating oscillatory shock model, oscillation of the Compton cloud is thought to cause QPOs. Thus, in order to increase QPO frequency, the Compton cloud must collapse steadily in the rising phase. In decline phases, the exact opposite should be true. We investigate cause of this evolution of the Compton cloud. The same viscosity parameter that increases the Keplerian disk rate also moves the inner edge of the Keplerian component, thereby reducing the size of the Compton cloud and reducing the cooling timescale. We show that cooling of the Compton cloud by inverse Comptonization is enough for it to collapse sufficiently so as to explain the QPO evolution. In the two-component advective flow configuration of Chakrabarti-Titarchuk, centrifugal force-induced shock represents the boundary of the Compton cloud. We take the rising phase of 2010 outburst of Galactic black hole candidate H 1743-322 and find an estimation of variation of the α parameter of the sub-Keplerian flow to be monotonically rising from 0.0001 to 0.02, well within the range suggested by magnetorotational instability. We also estimate the inward velocity of the Compton cloud to be a few meters per second, which is comparable to what is found in several earlier studies of our group by empirically fitting the shock locations with the time of observations.

  15. Sediment-palaeosol successions in Calabria and Sardinia suggest spatially differentiated palaeo-vegetation patterns in southern Italy during the Last Glacial period

    NASA Astrophysics Data System (ADS)

    Sauer, Daniela; Zucca, Claudio; Al-Sharif, Riyad; Zwanzig, Lisa; Madrau, Salvatore; Andreucci, Stefano; Pascucci, Vincenzo; Kadereit, Annette; Scarciglia, Fabio; Brückner, Helmut

    2016-04-01

    .9-30.3 ka cal BP, respectively. Thus, the formation of these soils falls into the period for which the lacustrine record indicates alternations between open and wooded steppe. The second palaeosol-sediment succession was found in a similar geomorphological situation near Piale, ca. 30 km north of the Lazzaro profile. In this case, the major part of the alluvial fan was removed by the creek (flowing from east to west), so that only its southernmost edge is preserved. SOM of the two lowermost palaeosols embedded in it was 14C-dated to 44.8-45.8 ka cal BP and 45.2-46.2 ka cal BP, respectively. The palaeosols of the Piale profile are very dark, almost carbonate-free, and several of them are characterized by an aeolian component (volcanic ash). The third sediment-palaeosol succession is exposed at the north-western coast of Sardinia, ca. 1.5 km north of Porto Palmas. The succession has developed in alluvial fan deposits that are constrained in a narrow valley, thus forming a valley infilling. Where the valley opens into the sea, this infilling is exposed in a high cliff. The sediment-palaeosol succession is sandwiched between marine deposits at the bottom (attributed to MIS 5c), and a sandy cover on top, dated to 23±4 ka by optically stimulated luminescence (OSL). 14C dating was performed on charcoal fragments that were abundant in several horizons. Interestingly, in contrast to the two sediment-palaeosol successions in Calabria, the palaeosols exposed in NW Sardinia do not represent dark steppe and forest steppe soils. The NW Sardinian Late Pleistocene palaeosols are brownish, reflecting rather forest environments. This difference suggests somewhat more humid and less continental conditions in this area compared to Calabria, during the Last Glacial period. However, more of these terrestrial archives along the coast of S Italy would need to be studied to gain a deeper understanding of spatial patterns of Last Glacial vegetation and environments.

  16. VizieR Online Data Catalog: Observed Periods of Ap and Bp stars (Catalano+ 1998)

    NASA Astrophysics Data System (ADS)

    Catalano, F. A.; Renson, P.

    1997-11-01

    A catalogue of all the periods published up to 31 October 1996 on 364 CP stars is presented; it supersedes the previous version (catalog ). The paper version (catalog.tex) is arranged in three tables: the bulk of the data, i.e. those referring to CP2, CP3, and CP4 stars, are given in Table 1, while the data concerning He-strong stars are given in Table 2 and those for eclipsing or ellipsoidal variables are collected in Table 3. Notes are also provided at the end of each table, mainly about duplicities. The machine-readable version was arranged in two main parts: the main parameters of the 364 stars (identifiers and names, positions, spectral types, magnitudes and peculiarities) are tabulated in the file 'stars'; periods and the of the observed variations (light, spectrum, magnetic field, etc.) are listed in the 'periods' file. Two other files contains the notes and the references. (5 data files).

  17. Elemental GCR Observations during the 2009-2010 Solar Minimum Period

    NASA Technical Reports Server (NTRS)

    Lave, K. A.; Israel, M. H.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; deNolfo, G. A.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.; vonRosenvinge, T. T.; Wiedenbeck, M. E.

    2013-01-01

    Using observations from the Cosmic Ray Isotope Spectrometer (CRIS) onboard the Advanced Composition Explorer (ACE), we present new measurements of the galactic cosmic ray (GCR) elemental composition and energy spectra for the species B through Ni in the energy range approx. 50-550 MeV/nucleon during the record setting 2009-2010 solar minimum period. These data are compared with our observations from the 1997-1998 solar minimum period, when solar modulation in the heliosphere was somewhat higher. For these species, we find that the intensities during the 2009-2010 solar minimum were approx. 20% higher than those in the previous solar minimum, and in fact were the highest GCR intensities recorded during the space age. Relative abundances for these species during the two solar minimum periods differed by small but statistically significant amounts, which are attributed to the combination of spectral shape differences between primary and secondary GCRs in the interstellar medium and differences between the levels of solar modulation in the two solar minima. We also present the secondary-to-primary ratios B/C and (Sc+Ti+V)/Fe for both solar minimum periods, and demonstrate that these ratios are reasonably well fit by a simple "leaky-box" galactic transport model that is combined with a spherically symmetric solar modulation model.

  18. Substorms observations during two geomagnetically active periods in March 2012 and March 2015

    NASA Astrophysics Data System (ADS)

    Guineva, V.; Despirak, I.; Kozelov, B.

    2016-05-01

    In this work two events of strong geomagnetic activity were examined: the period 7-17 March 2012, which is one of the most disturbed periods during the ascending phase of Solar Cycle 24, and the severe geomagnetic storm on 17-20 March 2015. During the first period four consecutive magnetic storms occurred on 7, 9, 12, and 15 March. These storms were caused by Sheath, MC and HSS, and the detailed scenarios for the storms were different. The second event is a storm of fourth level with Kp = 8, the strongest one during the last four years, the so-called "St. Patrick's Day 2015 Event". A geomagnetic storm of such intensity was observed in September 2011. Our analysis was based on the 10-s sampled IMAGE magnetometers data, the 1-min sampled OMNI solar wind and interplanetary magnetic field (IMF) data and observations of the Multiscale Aurora Imaging Network (MAIN) in Apatity. The particularities in the behaviours of substorms connected with different storms during these two interesting strongly disturbed periods are discussed.

  19. Observations of simple RNA suboptimal structures including pseudoknots suggests that the folding landscape is often funnel shaped

    NASA Astrophysics Data System (ADS)

    Dawson, Wayne; Kawai, Gota

    2008-03-01

    Many RNA structure are known to fold up into complex function structures such as ribosomal RNA, transfer RNA (tRNA), riboswitches, etc. We are currently developing a novel theoretical approach for predicting the base pairing topology of folded RNA structures [1,2], a term known as RNA secondary structure. A good prediction of this base pairing can significantly speed up computation of the full 3D structure of these complex molecules. In recent work, we reported a pseudoknot prediction application using this model [3]. We have now upgraded this application to also predict suboptimal structures. The results of this model suggest that structures like tRNA often have a folding landscape of suboptimal structures that is essentially funnel shaped; similar to what is known to be the case for many simple proteins. This model has also been applied to simple protein structure topology prediction in a similar fashion. [1] Dawson, et al. (2001). J Theor Biol. 213, 359-386 and 387-412. [2] Dawson, et al. (2006). Nucleosides, Nucleotides, and Nucleic Acids 25, 171-189. [3]Dawson, et al. (2007). PLoS One, 2, 905.

  20. Implications of the observed distributions of very long period comet orbits

    NASA Astrophysics Data System (ADS)

    Harrington, R. S.

    1985-01-01

    It is argued that the calculations of Van Flandern (1977), and Byl (1983) seriously underestimate the effects of galactic perturbations on the distributions and orientations of very-long-period comets. Revised calculations are given which take into account the effects of galactic perturbation and observational error. It is shown that the revised calculations are consistent with a uniform distribution of comets within the Oort Cloud.

  1. Observed Temporal Evolution of Global Mean Age of Stratospheric Air for the 2002 to 2010 Period

    NASA Astrophysics Data System (ADS)

    Stiller, G. P.; von Clarmann, T.; Haenel, F.; Funke, B.; Glatthor, N.; Grabowski, U.; Kellmann, S.; Kiefer, M.; Linden, A.; Lossow, S.; Lopez-Puertas, M.

    2011-12-01

    According to model calculations, the meridional circulation is expected to intensify as a result of climate change, and mean age of stratospheric air is expected to decrease. However, an observational data set presented recently (Engel et al., 2009) and consisting of 27 balloon samples of the age of air tracers carbon dioxide and sulfur hexafluoride covering the years 1975 to 2005 did not confirm the model predictions. As a contribution to the ongoing discussion, an extensive observational data set, consisting of more than 1 Million SF6 vertical profiles distributed globally is presented here. It has been derived from the MIPAS instrument covering the period 2002 to 2010 and has been converted into mean age of stratospheric air by referring to a combined data set of in-situ and flask global mean tropospheric SF6 measurements provided by NOAA/ESRL. During conversion into age of air, the non-linearity of tropospheric SF6 increase has been corrected for by convolution with the age spectrum within an iterative approach. Monthly zonal means of mean age of air, binned at 10 deg latitude and 1-2 km altitude, were analyzed with respect to their temporal variation by fitting a regression model consisting of a constant and a linear increase term, 2 proxies for the QBO variation, sinusoidal terms for the seasonal and semi-annual variation and overtones for the correction of the shapes to the observed data set. The impact of subsidence of mesospheric SF6-depleted air and in-mixing into non-polar latitudes on mid-latitudinal absolute age of air and the age-of-air linear increase was assessed and found to be small. The linear increase of mean age of stratospheric air was found to be positive and partly larger than the trend derived by Engel et al. (2009) for most of the Northern mid-latitudes, the middle stratosphere in the tropics, and parts of the Southern mid-latitudes, as well as for the Southern polar upper stratosphere. Multi-year decrease of age of air was found for the

  2. Summed Probability Distribution of 14C Dates Suggests Regional Divergences in the Population Dynamics of the Jomon Period in Eastern Japan

    PubMed Central

    Habu, Junko; Kobayashi, Kenichi; Madella, Marco

    2016-01-01

    Recent advances in the use of summed probability distribution (SPD) of calibrated 14C dates have opened new possibilities for studying prehistoric demography. The degree of correlation between climate change and population dynamics can now be accurately quantified, and divergences in the demographic history of distinct geographic areas can be statistically assessed. Here we contribute to this research agenda by reconstructing the prehistoric population change of Jomon hunter-gatherers between 7,000 and 3,000 cal BP. We collected 1,433 14C dates from three different regions in Eastern Japan (Kanto, Aomori and Hokkaido) and established that the observed fluctuations in the SPDs were statistically significant. We also introduced a new non-parametric permutation test for comparing multiple sets of SPDs that highlights point of divergences in the population history of different geographic regions. Our analyses indicate a general rise-and-fall pattern shared by the three regions but also some key regional differences during the 6th millennium cal BP. The results confirm some of the patterns suggested by previous archaeological studies based on house and site counts but offer statistical significance and an absolute chronological framework that will enable future studies aiming to establish potential correlation with climatic changes. PMID:27128032

  3. Summed Probability Distribution of 14C Dates Suggests Regional Divergences in the Population Dynamics of the Jomon Period in Eastern Japan.

    PubMed

    Crema, Enrico R; Habu, Junko; Kobayashi, Kenichi; Madella, Marco

    2016-01-01

    Recent advances in the use of summed probability distribution (SPD) of calibrated 14C dates have opened new possibilities for studying prehistoric demography. The degree of correlation between climate change and population dynamics can now be accurately quantified, and divergences in the demographic history of distinct geographic areas can be statistically assessed. Here we contribute to this research agenda by reconstructing the prehistoric population change of Jomon hunter-gatherers between 7,000 and 3,000 cal BP. We collected 1,433 14C dates from three different regions in Eastern Japan (Kanto, Aomori and Hokkaido) and established that the observed fluctuations in the SPDs were statistically significant. We also introduced a new non-parametric permutation test for comparing multiple sets of SPDs that highlights point of divergences in the population history of different geographic regions. Our analyses indicate a general rise-and-fall pattern shared by the three regions but also some key regional differences during the 6th millennium cal BP. The results confirm some of the patterns suggested by previous archaeological studies based on house and site counts but offer statistical significance and an absolute chronological framework that will enable future studies aiming to establish potential correlation with climatic changes. PMID:27128032

  4. Local Scale Radiobrightness Modeling During the Intensive Observing Period-4 of the Cold Land Processes Experiment-1

    NASA Technical Reports Server (NTRS)

    Kim, Edward J.; Tedesco, Marco; deRoo, Roger; England, Anthony W.; Gu, Hao-Yu; Pham, Hanh; Boprie, David; Graf, Tobias; Koike, Toshio; Armstrong, Richard

    2005-01-01

    The NASA Cold Land Processes Field Experiment (CLPX-1) was designed to provide microwave remote sensing observations and ground truth for studies of snow and frozen ground remote sensing, particularly issues related to scaling. CLPX-1 was conducted in 2002 and 2003 in Colorado, USA. One of the goals of the experiment was to test the capabilities of microwave emission models at different scales. Initial forward model validation work has concentrated on the Local-Scale Observation Site (LSOS), a 0.8 ha study site consisting of open meadows separated by trees where the most detailed measurements were made of snow depth and temperature, density, and grain size profiles. Results obtained in the case of the 3& Intensive Observing Period (IOP3) period (Feb., 2003, dry snow) suggest that a model based on Dense Medium Radiative Transfer (DMRT) theory is able to model the recorded brightness temperatures using snow parameters derived from field measurements. This paper focuses on the ability of forward DMRT modelling, combined with snowpack measurements, to reproduce the radiobrightness signatures observed by the University of Michigan s Truck-Mounted Radiometer System (TMRS) at 19 and 37 GHz during the 4th IOP (IOP4) in March, 2003. Unlike IOP3, conditions during IOP4 include both wet and dry periods, providing a valuable test of DMRT model performance. In addition, a comparison will be made for the one day of coincident observations by the University of Tokyo's Ground-Based Microwave Radiometer-7 (GBMR-7) and the TMRS. The plot-scale study in this paper establishes a baseline of DMRT performance for later studies at successively larger scales. And these scaling studies will help guide the choice of future snow retrieval algorithms and the design of future Cold Lands observing systems.

  5. Progresses on the Intensive Observation Period of Watershed Allied Telemetry Experimental Research

    NASA Astrophysics Data System (ADS)

    Li, Xin; Li, Xiaowen; Li, Zengyuan; Ma, Mingguo; Wang, Jian; Liu, Qiang; Xiao, Qing; Chen, Erxue; Che, Tao; Hu, Zeyong

    2010-05-01

    The Watershed Allied Telemetry Experimental Research (WATER) is an intensively simultaneous airborne, satellite-borne and ground based remote sensing experiment aiming to improve the observability, understanding, and predictability of hydrological and related ecological processes at catchment scale. It was taken place in the Heihe River Basin, the second largest inland river basin in the arid regions of northwest China. WATER consists of the cold region, forest, and arid region hydrological experiments as well as a hydrometeorology experiment. It was divided into 4 phases, namely, the experiment planning period, pre-observation period, intensive observation period (IOP) and persistent observation period. The field campaigns have been completed, with the IOP lasting from March 7 to April 12, May 15 to July 22, and August 23 to September 5, 2008, in total, 120 days, more than 280 individuals of scientists, engineers, students, and aircrews from 28 different institutes and universities were involved in. A total of 26 airborne missions, about 110 hours were flown. Airborne sensors including microwave radiometers at L, K and Ka bands, imaging spectrometer, thermal imager, CCD and LIDAR were used. Ground measurements were carried out concurrently with the airborne and space-borne remote sensing at four scales, i.e., key experimental area, foci experimental area, experiment site and elementary sampling plot. A network of hydro meteorological and flux observations was established in the upper and middle reaches of the Heihe River Basin. The network was composed of 12 super Automatic Meteorological Stations (AMS), 6 Eddy Covariance (EC) systems, 2 Large Aperture Scintillometers (LAS), and plenty of China Meteorological Administration (CMA) operational meteorological and hydrological stations. Additionally, we also used ground-based remote sensing instruments, such as Doppler Radar, ground based microwave radiometer and truck-mounted scatterometer and lots of auto

  6. Saturn's Ionospheric Clock(s): A Concept for Generating and Maintaining Saturn's Observed Magnetospheric Periodicities

    NASA Astrophysics Data System (ADS)

    Mitchell, D. G.; Brandt, P. C.; Ukhorskiy, A. Y.

    2010-12-01

    Saturn’s 10.X hour periodicity, observed throughout the magnetosphere, remains a mystery. It has been observed in many regions, modulating many phenomena. During the Cassini mission most observations have shown a period at about 10.8 hours, expressed in Saturn kilometric radiation from the high latitude auroral zone, in magnetic field components (both equatorial and high latitude) from 3 to 12 Rs, in current sheet encounters in the outer magnetosphere and magnetotail, in energetic neutral atom emission from the equatorial magnetosphere, and in plasma and energetic particles throughout the magnetosphere. More recently, various authors have shown at least two dominant periods expressed (in SKR and in magnetic field components), with slightly different values in the southern and northern hemispheres. The cause of this behavior is still not accounted for. Although loosely associated with Saturn’s rotation, the variability in the period precludes a direct connection with Saturn’s interior (e.g., a magnetic anomaly). Other candidates that have been discussed by others are an ionospheric source (conductivity anomaly), a perturbation in the cold plasma circulation pattern, a magnetospheric cam, asymmetric ring current particle pressure, and/or a natural frequency of the magnetosphere (cavity mode or traveling wave front of some sort). In this paper we present a concept that derives its energy from the subcorotating cold, dense plasma (which exhibits a rotation period on the order of 13 to 14 hours throughout L-shells between ~3 and 20), but is triggered by a process linked with the ionosphere. Key components of the model include significant slippage between the ionosphere and the magnetosphere (with the ionosphere rotating at the expressed period in each hemisphere, only slightly more slowly than the planet interior), subcorotating cold dense plasma with a source in the inner magnetosphere, predominantly radial transport of the cold dense plasma in the rotational

  7. Management of Toxoplasmic Retinochoroiditis during Pregnancy, Postpartum Period and Lactation: Clinical Observations

    PubMed Central

    Brydak-Godowska, Joanna; Moneta-Wielgoś, Joanna; Kęcik, Dariusz; Borkowski, Piotr Karol

    2015-01-01

    Background During pregnancy and labor, the immune response is physiologically impaired and women are more susceptible to infections. Since many drugs may have potentially adverse effects on the fetus and newborn, less aggressive treatment regimens should be considered in pregnant and lactating patients. The aim of our study was to present the management of toxoplasmic retinochoroiditis during pregnancy, postpartum period, and lactation. Material/Methods A retrospective study was undertaken of the clinical records of 24 women during pregnancy, postpartum period, and lactation who were referred in the years 1994–2014 to the Department of Zoonoses and Tropical Diseases or the Department of Ophthalmology, Medical University of Warsaw for toxoplasmic retinochoroiditis. The diagnosis was based on the typical ophthalmoscopic picture, confirmed by serological testing using an ELISA method. Results A total of 28 attacks of toxoplasmic retinochoroiditis were observed in 24 patients during pregnancy, postpartum period, and lactation. The choice of treatment was guided by the character and location of the inflammatory lesion and the gestational age. Topical (steroidal/nonsteroidal eye drops) and systemic treatments with spiramycin or azithromycin, Fansidar (pyrimethamine 25 mg/sulfadoxine 500 mg), and prednisone were used. Conclusions Management of toxoplasmic retinochoroiditis during pregnancy, postpartum period, or lactation must be individualized and guided by the gestational age and location of the active lesion. Women of childbearing age with toxoplasma ocular lesions should be informed by their doctors about possible active recurrences during pregnancy and followed carefully by an ophthalmologist when pregnant. PMID:25711713

  8. Confrontation Between a Quantized Periods of Some Exo-planetary Systems and Observations

    NASA Astrophysics Data System (ADS)

    El Fady Morcos, Abd

    2012-07-01

    Confrontation Between a Quantized Periods of Some Exo-planetary Systems and Observations A.B. Morcos Corot and Kepler were designed to detect Earth-like extra solar planets. The orbital elements and periods of these planets will contain some uncertainties. Many theoretical treatments depend on the idea of quantization were done aiming to find orbital elements of these exoplenets. In the present work, as an extension of previous works, the periods of some extoplanetary systems are calculated by using a simple derived formula. The orbital velocities of some of them are predicted . A comparison between the calculated and observed data is done References 1-J.M. Barnothy , the stability of the Solar System and of small Stellar Systems . (Y.Kazai edn,IAU,1974). 2-L.Nottale,Fractal Space-Time and Microphysics,Towards a Theory of Scale Relativity,( World Scientific, London,1994). 3-L. Nottale, A&A Lett. 315, L9 (1996). 4-L. Nottale, G. Schumacher and J. Gay, A&A , 322, 1018 , (1997). 5-L. Nottale, A&A , 361, 379 (2000). 6-A.G. Agnese and R.Festa, arXiv:astro-ph/9807186v1, (1998). 7-A.G. Agnese and R.Festa, arXiv:astro-ph/9910534v2. (1999). 8- A.B.Morcos, MG 12 , France (2009). 9- A.B.Morcs, Cospar 38 , Bremen , Germany (2010)

  9. Some observations regarding the thermal flux from Earth's erupting volcanoes for the period 2000 to 2014

    NASA Astrophysics Data System (ADS)

    Wright, R.; Blackett, M.; Hill-Butler, C.

    2014-12-01

    This presentation will describe 15 years of MODIS observations of the thermal flux from Earth's sub-aerially erupting volcanoes. The MODVOLC algorithm has been providing data regarding volcanic eruptions on Earth to the volcanological community since the launch of Terra MODIS, via the internet, in near-real-time (http:modis.higp.hawaii.edu). During this time, eruptions at 102 volcanoes have been observed, including activity associated with mafic lava flows, lava lakes, vent-based explosive activity and felsic lava domes. This presentation will present an overview of how MODIS has documented every eruption to occur on Earth since 2000, and will describe some of the more interesting result that have been obtained from the analysis of this archive. The total amount of energy radiated into the atmosphere can be divided into two parts: a baseline level of emission which has increased gradually over this 15 period, superimposed on which are large "spikes" attributable to large, lava-flow-forming eruptions. The most intense eruption during this period of time was the 2004 eruption of Nyamuragira, in the Democratic Republic of Congo, whilst the largest magnitude event was the 2012-2013 eruption of Tolbachik, Russia. Spatio-temporal patterns in thermal output will be addressed. Time-series analysis of heat flux from these 102 volcanoes has revealed while some volcanoes exhibit statistically significant periodicity in the magnitude of their heat output, many do not.

  10. Observing and Modeling Long-Period Tidal Variations in Polar Motion

    NASA Technical Reports Server (NTRS)

    Gross, Richard S.; Dickman, S. R.

    2011-01-01

    By exchanging angular momentum with the solid Earth, ocean tides cause the Earth's rotation to change. While hydrodynamic tide models have been used to study the effect of ocean tides on polar motion, it is shown here that none of the published models can fully account for the observed variations. An empirical ocean tide model is therefore determined by fitting periodic terms at the tidal frequencies to polar motion excitation observations, from which atmospheric and non-tidal oceanic effects were removed. While the empirical ocean tide model does fully account for allof the observed tidal power, tests indicate that the model may not have completely converged. So better models of the effects of ocean tides on polar motion are still needed, both dynamical and empirical.

  11. Observing and modeling long-period tidal variations in polar motion

    NASA Astrophysics Data System (ADS)

    Gross, R. S.; Dickman, S. R.

    2011-10-01

    By exchanging angular momentum with the solid Earth, ocean tides cause the Earth's rotation to change. While hydrodynamic tide models have been used to study the effect of ocean tides on polar motion, it is shown here that none of the published models can fully account for the observed variations. An empirical ocean tide model is therefore determined by fitting periodic terms at the tidal frequencies to polar motion excitation observations spanning 1980.0-2010.4 from which atmospheric and non-tidal oceanic effects were removed. While the empirical ocean tide model does fully account for all of the observed tidal power, tests indicate that the model may not have completely converged. So better models of the effects of ocean tides on polar motion are still needed, both dynamical and empirical.

  12. SOHO/SWAN OBSERVATIONS OF SHORT-PERIOD SPACECRAFT TARGET COMETS

    SciTech Connect

    Combi, M. R.; Lee, Y.; Patel, T. S.; Maekinen, J. T. T.; Bertaux, J.-L.; Quemerais, E.

    2011-04-15

    SWAN, the Solar Wind ANisotropies all-sky hydrogen Ly{alpha} camera on the Solar and Heliospheric Observatory spacecraft that makes all-sky images of interplanetary neutral hydrogen, has an ongoing campaign to make special observations of comets, both short- and long-period ones, in addition to the serendipitous observations of comets as part of the all-sky monitoring program. We report here on a study of several short-period comets that were detected by SWAN: 21P/Giacobini-Zinner (1998 and 2005 apparitions), 19P/Borrelly (2001 apparition), 81P/Wild 2 (1997 apparition), and 103P/Hartley 2 (1997 apparition). SWAN observes comets over long continuous stretches of their visible apparitions and therefore provides excellent temporal coverage of the water production. For some of the observations we are also able to analyze an entire sequence of images over many days to several weeks/months using our time-resolved model and extract daily average water production rates over continuous periods of several days to months. The short-term (outburst) and long-term behavior can be correlated with other observations. The overall long-term variation is examined in light of seasonal effects seen in the pre- to post-perihelion differences. For 21P/Giacobini-Zinner and 81P/Wild 2 the activity variations over each apparition were more continuously monitored but nonetheless consistent with previous observations. For 19P/Borrelly we found a very steep variation of water production rates, again consistent with some previous observations, and a variation over six months around perihelion that was reasonably consistent with the spin-axis model of Schleicher et al. and the illumination of the main active areas. During the 1997-1998 apparition of 103P/Hartley 2, the target comet of the EPOXI mission (the Deep Impact extended mission), we found a variation with heliocentric distance ({approx}r{sup -3.6}) that was almost as steep as 19P/Borrelly and, given the small measured radius near

  13. Periodicity in the spatial-temporal earthquake distributions for the Pacific region: observation and modeling.

    NASA Astrophysics Data System (ADS)

    Sasorova, Elena; Levin, Boris

    2014-05-01

    In the course of the last century a cyclic increasing and decreasing of the Earth's seismic activity (SA) was marked. The variations of the SA for the events with M>=7.0 from 1900 up to date were under study. The two subsets of the worldwide NEIC (USGS) catalog were used: USGS/NEIC from 1973 to 2012 and catalog of the significant worldwide earthquakes (2150 B.C. - 1994 A.D.), compiled by USGS/NEIC from the NOAA agency. The preliminary standardization of magnitudes and elimination of aftershocks from list of events was performed. The entire period of observations was subdivided into 5-year intervals. The temporal distributions of the earthquake (EQ) density and released energy density were calculated separately for the Southern hemisphere (SH), and for the Northern hemisphere (NH) and for eighteen latitudinal belts: 90°-80°N, 80°-70°N, 70°-60°N, 60°-50°N and so on (the size of each belt is equal to 10°). The periods of the SA was compared for different latitudinal belts of the Earth. The peaks and decays of the seismicity do not coincide in time for different latitudinal belts and especially for the belts located in NH and SH. The peaks and decays of the SA for the events (with M>=8) were marked in the temporal distributions of the EQ for all studied latitudinal belts. The two-dimension distributions (over latitudes and over time) of the EQ density and released energy density highlighted that the periods of amplification of the SA are equal to 30-35 years approximately. Next, we check the existence of a non-random component in the EQ occurrence between the NH and the SH. All events were related to the time axis according to their origin time. We take into consideration the set of the EQs in the studied catalog as the sequence of events if each event may have only one of two possible outcome (occurrence in the NH or in the SH). A nonparametric run test was used for testing of hypothesis about an existence the nonrandom component in the examined sequence of

  14. Observations of 20-day period meridional current oscillations in the upper ocean along the Pacific Equator

    NASA Technical Reports Server (NTRS)

    Halpern, David; Knox, Robert A.; Luther, Douglas S.

    1988-01-01

    Prominent oscillations of the meridional current, with a mean period of approximately 20 days, is observed in the upper ocean from May 1979 to October 1985 using moored current measurements along the Pacific equator at 95, 110, 124, 140, and 152 deg W, as well as off (but near) the equator at 110 and 140 deg W. The fluctuations are relatively narrowband in frequency. A 95 percent statistically significant peak in the power spectra of the meridional current occurs at 110, 124, and 140 deg W, but not at 95 and 152 deg W where the spectral peaks are smaller. The dominant wave period decreases by about 4 percent from 110 to 140 deg W. The wave amplitude decreases with depth, and the wave is essentially confined to the upper 80 m. The penetration depth of the oscillation is greatest at 110 deg W and least at 140 deg W.

  15. On quasi-periodic variations of low-energy cosmic rays observed near earth.

    PubMed

    Kudela, Karel; Langer, Ronald

    2015-06-01

    Cosmic ray (CR) may partially, especially at high altitudes, contribute to the dosimetric characteristics. Along with irregular CR variations as Forbush decreases and solar particle events are, the quasi-periodic variations may be of some relevance too. A very short review (with references to original papers) of the present knowledge of various types of such variations is presented, namely (i) diurnal wave, (ii) ~27 d variability due to the solar rotation, (iii) Rieger-type periodicity, and (iv) quasi-biennial oscillations as well as waves on longer time scales related to solar activity and to polarity of magnetic field of the Sun. Variability is illustrated in measurements of secondary CR on the ground including the high-altitude observations at Lomnický štít. PMID:25979741

  16. Results of IPS Observations in the Period Near Solar Activity Minimum

    NASA Astrophysics Data System (ADS)

    Chashei, I. V.; Shishov, V. I.; Tyul'bashev, S. A.; Subaev, I. A.; Oreshko, V. V.

    2013-07-01

    IPS observations with the Big Scanning Array of Lebedev Physical Institute (BSA LPI) radio telescope at the frequency 111 MHz have been monitored since 2006. All the sources, about several hundred daily, with a scintillating flux greater than 0.2 Jy are recorded for 24 hours in the 16 beams of the radio telescope covering a sky strip of 8∘ declination width. We present some results of IPS observations for the recent period of low solar activity considering a statistical ensemble of scintillating radio sources. The dependences of the averaged over ensemble scintillation index on heliocentric distance are considerably weaker than the dependence expected for a spherically symmetric geometry. The difference is especially pronounced in the year 2008 during the very deep solar activity minimum period. These features are explained by the influence of the heliospheric current sheet that is seen as a strong concentration of turbulent solar wind plasma aligned with the solar equatorial plane. A local maximum of the scintillation index is found in the anti-solar direction. Future prospects of IPS observations using BSA LPI are briefly discussed.

  17. Time Periods of Unusual Density Behavior Observed by GRACE and CHAMP

    NASA Astrophysics Data System (ADS)

    McLaughlin, C. A.; Fattig, E.; Mysore Krishna, D.; Locke, T.; Mehta, P. M.

    2011-12-01

    Time periods of low cross correlation between precision orbit ephemeris (POE) derived density and accelerometer density for CHAMP and GRACE are examined. In particular, the cross correlation for GRACE dropped from typical values near 0.9 to much lower values and then returned to typical over the time period of late October to late December of 2005. This time period includes a maneuver where GRACE-A and GRACE-B swapped positions. However, the drop in cross correlation begins and reaches its low point before the maneuvers begin. In addition, the densities were found using GRACE-A, but GRACE-B did most of the maneuvering. The time period is characterized by high frequency variations in accelerometer density of the same magnitude as the daylight to eclipse variations over the course of an orbit. However, the daylight to eclipse variations are particularly small during this time period because the orbit plane is near the terminator. Additionally, the difference between the accelerometer and POE derived densities are not unusually large during this time period. This implies the variations are not unusual, just more significant when the orbit plane is near terminator. Cyclical variations in correlation of the POE derived densities with accelerometer derived densities are seen for both GRACE and CHAMP, but the magnitude of the variations are much larger for GRACE, possibly because of the higher altitude of GRACE. The cycles seem to be phased so that low correlations occur with low beta angle when the orbit plane is near the terminator. The low correlation is possibly caused by the lower amplitude of the daylight to eclipse signal making higher frequency variations relatively more important. However, another possible explanation is terminator waves in density that propagate to the thermosphere from lower in the atmosphere. These waves have been observed in CHAMP accelerometer data and global circulation model simulations. Further investigation is needed to see if the

  18. IUE observations of long period eclipsing binaries - A study of accretion onto non-degenerate stars

    NASA Technical Reports Server (NTRS)

    Plavec, M. J.

    1980-01-01

    IUE observations made in 1978-1979 recorded a whole class of interacting long-period binaries similar to beta Lyrae, which includes RX Cas, SX Cas, V 367 Cyg, W Cru, beta Lyr, and W Ser, called the W Serpentis stars. These mass-transferring binaries with relatively high mass transfer rate show two prominent features in the far ultraviolet: a continuum with a color temperature higher than the one observed in the optical region (about 12,000 K), and a strong emission line spectrum with the N V doublet at 1240 A, C IV doublet at 1550 A and lines of Si II, Si III, Si IV, C II, Fe III, AI III, etc. These phenomena are discussed on the assumption that they are due to accretion onto non-degenerate stars.

  19. Observation of gamma rays with a 4.8 hour periodicity from CYG X-3

    NASA Technical Reports Server (NTRS)

    Lamb, R. C.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.

    1976-01-01

    Energetic (E35 MeV) Gamma rays were observed from Cyg X-3 with the SAS-2 Gamma ray telescope. They are modulated at the 4.8 sup h period observed in the X-ray and infrared regions, and within the statistical error are in phase with this emission. The flux above 100 MeV has an average value of (4.4 + or - 1.1)x 10 to the -6 power/sq cm/sec. If the distance to Cyg X-3 is 10 kpcs, this flux implies a luminosity of more than 10 to the 37th power ergs/s if the radiation is isotropic and about 10 to the 36th power ergs/s if the radiation is restricted to a cone of one steradian, as it might be in a pulsar.

  20. Ginga observations of quasi-periodic oscillations in type II bursts from the Rapid Burster

    NASA Technical Reports Server (NTRS)

    Dotani, T.; Mitsuda, K.; Inoue, H.; Tanaka, Y.; Kawai, N.

    1990-01-01

    During Ginga observations of the 'Rapid Burster' in August 1988, strong quasi-periodic oscillations (QPOs) were detected in its X-ray intensity. The QPOs had centroid frequencies of 5 and 2 Hz during type II X-ray bursts which lasted for 10 and 30 s, respectively. The presence of the QPOs is correlated with the time scale-invariant burst profile. They are very strong during the initial peak in the burst, absent in the second peak, and strong again at the onset of the third peak. From an analysis of the X-ray spectrum as observed during the maxima and minima of the oscillations, it is found that the oscillations can be described by changes of the temperature of a blackbody emitter of constant apparent area.

  1. Cluster observations of quasi-periodic impulsive signatures in the dayside northern lobe: High-latitude flux transfer events?

    NASA Technical Reports Server (NTRS)

    Thompson, S. M.; Kivelson, M. G.; Khurana, K. K.; Balogh, A.; Reme, H.; Fazakerley, A. N.; Kistler, L. M.

    2004-01-01

    We report on a series of quasi-periodic reversals in GSM B(sub Z) observed by the four Cluster spacecraft in the northern dayside lobe poleward of the cusp on 23 February 2001. During an interval of about 35 min, multiple reversals (negative to positive) in B(sub Z) of approximately 1-min duration with an approximate 8-min recurrence time were observed. The individual structures do not resemble low-latitude flux transfer events (FTE) [Russell and Elphic, 1979] but the 8-min recurrence frequency suggests that intermittent reconnection may be occurring .Measurements (appropriately lagged) of the solar wind at ACE show that the IMF was southward-oriented with a strong B(sub X) and that a modest dynamic pressure increased as the events started. The multi-point observations afforded by the Cluster spacecraft were used to infer the motion (direction and speed) of the observed magnetic field reversals. The associated currents were also calculated and they are consistent with the spatial confinement of the observed magnetic field reversals. We propose that the observed reversals are due to flux tubes reconnecting with closed field lines on the dayside. Ancillary data from the Cluster Ion Spectrometry (CIS) and Plasma Electron And Current Experiment (PEACE) instruments were used to develop a physical picture of the reversals.

  2. Strong aerosol-cloud interaction in altocumulus during updraft periods: lidar observations over central Europe

    NASA Astrophysics Data System (ADS)

    Schmidt, J.; Ansmann, A.; Bühl, J.; Wandinger, U.

    2015-09-01

    For the first time, a liquid-water cloud study of the aerosol-cloud-dynamics relationship, solely based on lidar, was conducted. Twenty-nine cases of pure liquid-water altocumulus layers were observed with a novel dual-field-of-view Raman lidar over the polluted central European site of Leipzig, Germany, between September 2010 and September 2012. By means of the novel Raman lidar technique, cloud properties such as the droplet effective radius and cloud droplet number concentration (CDNC) in the lower part of altocumulus layers are obtained. The conventional aerosol Raman lidar technique provides the aerosol extinction coefficient (used as aerosol proxy) below cloud base. A collocated Doppler lidar measures the vertical velocity at cloud base and thus updraft and downdraft occurrence. Here, we present the key results of our statistical analysis of the 2010-2012 observations. Besides a clear aerosol effect on cloud droplet number concentration in the lower part of the altocumulus layers during updraft periods, turbulent mixing and entrainment of dry air is assumed to be the main reason for the found weak correlation between aerosol proxy and CDNC higher up in the cloud. The corresponding aerosol-cloud interaction parameter based on changes in cloud droplet number concentration with aerosol loading was found to be close to 0.8 at 30-70 m above cloud base during updraft periods and below 0.4 when ignoring vertical-wind information in the analysis. Our findings are extensively compared with literature values and agree well with airborne observations.

  3. Estimating interevent time distributions from finite observation periods in communication networks

    NASA Astrophysics Data System (ADS)

    Kivelä, Mikko; Porter, Mason A.

    2015-11-01

    A diverse variety of processes—including recurrent disease episodes, neuron firing, and communication patterns among humans—can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

  4. Periodic behaviors in the observed vertical column abundances of atmospheric hydroxyl

    NASA Technical Reports Server (NTRS)

    Burnett, Elizabeth Beaver; Burnett, Clyde R.; Minschwaner, Kenneth R.

    1989-01-01

    The data base for the vertical column abundance of atmospheric hydroxyl (OH) for Fritz Peak Observatory, Colorado (40 N, 105 W), now extends from 1976 through 1988 and is composed of 8849 independent data sets, averaging about 15 percent uncertainty and 20-minute time resolution each. The dominant solar zenith angle (chi) dependence of the OH abundance is characterized by an empirical curve, N(88), which has been updated from N(82) to include all valid data from 1980 through 1988. The chi-dependence of the OH abundance has been, to a first order, removed from the data base by a normalization procedure in which each data point is divided by the N(88,AM) value for the corresponding solar zenith angle. The resulting normalized OH values may then be examined for other systematic effects, particularly for periodic variations. Observations have also been made at Boca Raton, Florida (26 N, 80 W) and at Truk, Federated States of Micronesia (7 N, 152 E). These data bases are much less extensive and, as such, are less amenable to analysis for periodic behaviors. Some comparisons with the Colorado data may be made, however.

  5. An overview of an intensive observation period on variability of coastal atmospheric refractivity

    NASA Astrophysics Data System (ADS)

    Paulus, Richard A.

    1995-02-01

    This paper is an overview of an experiment called Variability of Coastal Atmospheric Refractivity (VOCAR). VOCAR was designed to be conducted under a larger program called Coastal Variability Analysis, Measurements, and Prediction and is a multi-year experimental effort to investigate the variability of atmospheric refractivity with emphasis on the coastal zone. The experiment is being conducted jointly with the Naval Air Warfare Center Weapons Division, Point Mugu, CA, the Naval Research Laboratory, and the Naval Postgraduate School. In addition, the National Oceanic and Atmospheric Administration Environmental Technology Laboratory and Penn State University/Applied Research Laboratory are participating in the measurement phase of VOCAR. The propagation measurements being made during VOCAR consist of monitoring signal strength variations of VHF/UHF transmitters in the southern California coastal region. Corresponding meteorological measurements are made during routine, special, and intensive observation periods. During an intensive measurement period from 23 August to 3 September 1993, radio data were collected at two receiver sites and meteorological data were collected from three profiler sites, eight radiosonde sites, three aircraft, and numerous surface weather sites. Samples of the data will be shown.

  6. "Radiative Closure Studies for Clear Skies During the ARM 2003 Aerosol Intensive Observation Period"

    SciTech Connect

    J. J. Michalsky, G. P. Anderson, J. Barnard, J. Delamere, C. Gueymard, S. Kato, P. Kiedron, A. McComiskey, and P. Ricchiazzi

    2006-04-01

    The Department of Energy's Atmospheric Radiation Measurement (ARM) program sponsored a large intensive observation period (IOP) to study aerosol during the month of May 2003 around the Southern Great Plains (SGP) Climate Research Facility (CRF) in north central Oklahoma. Redundant measurements of aerosol optical properties were made using different techniques at the surface as well as in vertical profile with sensors aboard two aircraft. One of the principal motivations for this experiment was to resolve the disagreement between models and measurements of diffuse horizontal broadband shortwave irradiance at the surface, especially for modest aerosol loading. This paper focuses on using the redundant aerosol and radiation measurements during this IOP to compare direct beam and diffuse horizontal broadband shortwave irradiance measurements and models at the surface for a wide range of aerosol cases that occurred during 30 clear-sky periods on 13 days of May 2003. Models and measurements are compared over a large range of solar-zenith angles. Six different models are used to assess the relative agreement among them and the measurements. Better agreement than previously achieved appears to be the result of better specification of input parameters and better measurements of irradiances than in prior studies. Biases between modeled and measured direct irradiances are less than 1%, and biases between modeled and measured diffuse irradiances are less than 2%.

  7. Observation of Exchange Anisotropy in Single-Phase Layer-Structured Oxides with Long Periods

    PubMed Central

    Huang, Yan; Wang, Guopeng; Sun, Shujie; Wang, Jianlin; Peng, Ranran; Lin, Yue; Zhai, Xiaofang; Fu, Zhengping; Lu, Yalin

    2015-01-01

    A remarkable exchange bias effect arising from the temperature-dependent interaction among the ferromagnetic-like cluster glasses and antiferromagnetic regions was observed in a newly developed single-phase multiferroic compound of Bi10Fe6Ti3O30 which has a nine-layer Aurivillius structure. Inhomogeneous distribution of magnetic Fe ions inside this long-period layered structure was experimentally identified via the atomic level imaging. The results confirmed the presence of the short-range magnetic ordering (the cluster glassy state) and the canted antiferromagnetism, and then the direct interaction among them was further confirmed. Finding of this new single-phase material accompanying this remarkable exchange bias effect would be beneficial to both basic physics understanding and the potential device development. PMID:26487509

  8. Observations of a new class of upstream waves with periods near 3 seconds

    NASA Technical Reports Server (NTRS)

    Le, G.; Russell, C. T.; Thomsen, M. F.; Gosling, J. T.

    1992-01-01

    A new class of ULF waves with periods near 3 s in the earth's upstream region is found by examining the high time resolution magnetic field data from the ISEE spacecraft. These waves are observed in the part of the upstream region which is magnetically connected to the bow shock, but only when the solar wind plasma beta is high (greater than 1). The waves are always right-handed, nearly circularly polarized in the spacecraft frame. The directions of the wave vectors are in the general direction of the average magnetic field, and the waves are convected downstream in the spacecraft frame. This study of these waves has shown that they appear to be intrinsically left-handed ion cyclotron waves in the plasma rest frame.

  9. Observation of stimulated emission in an ultrashort-period nonsymmetric GaAs/AlAs superlattice

    SciTech Connect

    Litovchenko, V. G.; Korbutyak, D. V.; Bercha, A. I.; Kryuchenko, Yu. V.; Krylyuk, S. G.; Grahn, H. T.; Hey, R.; Ploog, K. H.

    2001-06-25

    Nonsymmetric short-period GaAs/AlAs superlattices, for which the well thickness is at least a factor of 2 larger than the barrier thickness, have been shown to exhibit a direct band gap for any well thickness. These superlattices are characterized by an enhanced intensity of the luminescence as compared to their symmetric indirect-gap counterparts with the same well width, and, thus, may be used as light-emitting devices, in particular, as low-threshold lasers in the red visible spectrum. This conjecture is supported by the observation of stimulated emission at T=80K for a GaAs/AlAs superlattice with six monolayers well and three monolayers barrier width. {copyright} 2001 American Institute of Physics.

  10. Substorms observations over Apatity during geomagnetic storms in the period 2012 - 2016

    NASA Astrophysics Data System (ADS)

    Guineva, Veneta; Werner, Rolf; Despirak, Irina; Kozelov, Boris

    2016-07-01

    In this work we studied substorms, generated during enhanced geomagnetic activity in the period 2012 - 2016. Observations of the Multiscale Aurora Imaging Network (MAIN) in Apatity have been used. Solar wind and interplanetary magnetic field parameters were judged by the 1-min sampled OMNI data base. Substorm onset and further development were verified by the 10-s sampled data of IMAGE magnetometers and by data of the all-sky camera at Apatity. Subject of the study were substorms occurred during geomagnetic storms. The so-called "St. Patrick's day 2015 event" (17-21 March 2015), the events on 17-18 March 2013 and 7-17 March 2012 (a chain of events generated four consecutive storms) which were among the events of strongest geomagnetic activity during the current solar cycle 24, were part of the storms under consideration. The behavior of the substorms developed during different phases of the geomagnetic storms was discussed.

  11. Turbulence Kinetic Energy budget during the afternoon transition - Part 1: Observed surface TKE budget and boundary layer description for 10 intensive observation period days

    NASA Astrophysics Data System (ADS)

    Nilsson, E.; Lohou, F.; Lothon, M.; Pardyjak, E.; Mahrt, L.; Darbieu, C.

    2015-11-01

    The decay of turbulence kinetic energy (TKE) and its budget in the afternoon period from mid-day until zero buoyancy flux at the surface is studied in a two-part paper by means of measurements from the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign for 10 Intensive Observation Period days. Here, in Part 1, near-surface measurements from a small tower are used to estimate a TKE budget. The overall boundary layer characteristics and meso-scale situation at the site are also described based upon taller tower measurements, radiosoundings and remote sensing instrumentation. Analysis of the TKE budget during the afternoon transition reveals a variety of different surface layer dynamics in terms of TKE and TKE decay. This is largely attributed to variations in the 8 m wind speed, which is responsible for different amounts of near-surface shear production on different afternoons and variations within some of the afternoon periods. The partitioning of near surface production into local dissipation and transport in neutral and unstably stratified conditions was investigated. Although variations exist both between and within afternoons, as a rule of thumb, our results suggest that about 50 % of the near surface production of TKE is compensated by local dissipation near the surface, leaving about 50 % available for transport. This result indicates that it is important to also consider TKE transport as a factor influencing the near-surface TKE decay rate, which in many earlier studies has mainly been linked with the production terms of TKE by buoyancy and wind shear. We also conclude that the TKE tendency is smaller than the other budget terms, indicating a quasi-stationary evolution of TKE in the afternoon transition. Even though the TKE tendency was observed to be small, a strong correlation to mean buoyancy production of -0.69 was found for the afternoon period. For comparison with previous results, the TKE budget terms are normalized with

  12. Turbulence kinetic energy budget during the afternoon transition - Part 1: Observed surface TKE budget and boundary layer description for 10 intensive observation period days

    NASA Astrophysics Data System (ADS)

    Nilsson, Erik; Lohou, Fabienne; Lothon, Marie; Pardyjak, Eric; Mahrt, Larry; Darbieu, Clara

    2016-07-01

    The decay of turbulence kinetic energy (TKE) and its budget in the afternoon period from midday until zero-buoyancy flux at the surface is studied in a two-part paper by means of measurements from the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign for 10 intensive observation period days. Here, in Part 1, near-surface measurements from a small tower are used to estimate a TKE budget. The overall boundary layer characteristics and mesoscale situation at the site are also described based upon taller tower measurements, radiosoundings and remote sensing instrumentation. Analysis of the TKE budget during the afternoon transition reveals a variety of different surface layer dynamics in terms of TKE and TKE decay. This is largely attributed to variations in the 8 m wind speed, which is responsible for different amounts of near-surface shear production on different afternoons and variations within some of the afternoon periods. The partitioning of near-surface production into local dissipation and transport in neutral and unstably stratified conditions was investigated. Although variations exist both between and within afternoons, as a rule of thumb, our results suggest that about 50 % of the near-surface production of TKE is compensated for by local dissipation near the surface, leaving about 50 % available for transport. This result indicates that it is important to also consider TKE transport as a factor influencing the near-surface TKE decay rate, which in many earlier studies has mainly been linked with the production terms of TKE by buoyancy and wind shear. We also conclude that the TKE tendency is smaller than the other budget terms, indicating a quasi-stationary evolution of TKE in the afternoon transition. Even though the TKE tendency was observed to be small, a strong correlation to mean buoyancy production of -0.69 was found for the afternoon period. For comparison with previous results, the TKE budget terms are normalized with

  13. Observation of Geometric Parametric Instability Induced by the Periodic Spatial Self-Imaging of Multimode Waves

    NASA Astrophysics Data System (ADS)

    Krupa, Katarzyna; Tonello, Alessandro; Barthélémy, Alain; Couderc, Vincent; Shalaby, Badr Mohamed; Bendahmane, Abdelkrim; Millot, Guy; Wabnitz, Stefan

    2016-05-01

    Spatiotemporal mode coupling in highly multimode physical systems permits new routes for exploring complex instabilities and forming coherent wave structures. We present here the first experimental demonstration of multiple geometric parametric instability sidebands, generated in the frequency domain through resonant space-time coupling, owing to the natural periodic spatial self-imaging of a multimode quasi-continuous-wave beam in a standard graded-index multimode fiber. The input beam was launched in the fiber by means of an amplified microchip laser emitting sub-ns pulses at 1064 nm. The experimentally observed frequency spacing among sidebands agrees well with analytical predictions and numerical simulations. The first-order peaks are located at the considerably large detuning of 123.5 THz from the pump. These results open the remarkable possibility to convert a near-infrared laser directly into a broad spectral range spanning visible and infrared wavelengths, by means of a single resonant parametric nonlinear effect occurring in the normal dispersion regime. As further evidence of our strong space-time coupling regime, we observed the striking effect that all of the different sideband peaks were carried by a well-defined and stable bell-shaped spatial profile.

  14. Observation of Geometric Parametric Instability Induced by the Periodic Spatial Self-Imaging of Multimode Waves.

    PubMed

    Krupa, Katarzyna; Tonello, Alessandro; Barthélémy, Alain; Couderc, Vincent; Shalaby, Badr Mohamed; Bendahmane, Abdelkrim; Millot, Guy; Wabnitz, Stefan

    2016-05-01

    Spatiotemporal mode coupling in highly multimode physical systems permits new routes for exploring complex instabilities and forming coherent wave structures. We present here the first experimental demonstration of multiple geometric parametric instability sidebands, generated in the frequency domain through resonant space-time coupling, owing to the natural periodic spatial self-imaging of a multimode quasi-continuous-wave beam in a standard graded-index multimode fiber. The input beam was launched in the fiber by means of an amplified microchip laser emitting sub-ns pulses at 1064 nm. The experimentally observed frequency spacing among sidebands agrees well with analytical predictions and numerical simulations. The first-order peaks are located at the considerably large detuning of 123.5 THz from the pump. These results open the remarkable possibility to convert a near-infrared laser directly into a broad spectral range spanning visible and infrared wavelengths, by means of a single resonant parametric nonlinear effect occurring in the normal dispersion regime. As further evidence of our strong space-time coupling regime, we observed the striking effect that all of the different sideband peaks were carried by a well-defined and stable bell-shaped spatial profile. PMID:27203323

  15. Possible identifications of newly observed magnetar quasi-periodic oscillations as crustal shear modes

    NASA Astrophysics Data System (ADS)

    Sotani, Hajime; Iida, Kei; Oyamatsu, Kazuhiro

    2016-02-01

    Quasi-periodic oscillations (QPOs) discovered in soft-gamma repeaters (SGRs) are expected to help us to study the properties of matter in neutron stars. In earlier investigations, we identified the QPOs of frequencies below ˜100 Hz observed in giant flares of SGR 1806 -20 and SGR 1900+14 as the crustal torsional oscillations. For this purpose, we calculated the frequencies of the fundamental torsional oscillations with various angular indices ℓ, by changing the stellar mass and radius. In this work, we try to explain the additional QPO frequencies recently reported by Huppenkothen et al. (2014a, 2014b) within the same framework as before except that we newly take into account the effect of electron screening, which acts to decrease the frequencies by a small amount. Those QPOs were discovered in two different SGRs, i.e., SGR 1806 -20 and SGR J1550 -5418. Then, we find that the newly observed QPO frequency in SGR 1806 -20 can be still identified as one of the frequencies of the fundamental torsional oscillations, while those in SGR J1550 -5418 can also be explained in terms of the torsional oscillations although the relevant angular indices are difficult to identify.

  16. Search for periodicity in the observational data by means of artificial neuron networks

    NASA Astrophysics Data System (ADS)

    Baluev, R.

    2012-05-01

    The possibility of application of artificial neural networks is considered for two classical model problems of observational data reduction: (i) the identification of periodic oscillations in noisy time series and (ii) assessment of the frequency of this oscillation (on the existing time series). On the inputs of the neural networks the values of the time series are given, and on the output, respectively, we have either an indicatior of the presence of signal (from 0 to 1), or the assessment of its frequency. It is shown that the theoretical limit, which a neural network can achieve in the training to solve such problems, corresponds to the Bayesian theory of estimation and testing of statistical hypotheses. Training of the neural network was carried out with a help of means of open-source package FANN. The best results were achieved using the algorithm Cascade2, which allows finding the optimal number of network neurons (not just the weight of the connection between them). In comparison with traditional methods based on the periodogram, which require long calculations, the trained neural network works almost instantly. Thus, artificial neural networks are very promising for the processing of large data sets. However, the threshold of signal detection so far failed to bring to Bayesian theoretical limit. In addition, it is not yet possible to train the neural network to analyze time-series with arbitrarily-uneven distribution of observations. This indicates on a need for further investigations to improve the efficiency of the method.

  17. The RR Lyrae period-K-luminosity relation for globular clusters: an observational approach

    NASA Astrophysics Data System (ADS)

    Sollima, A.; Cacciari, C.; Valenti, E.

    2006-11-01

    The period-metallicity-K-band luminosity (PLK) relation for RR Lyrae stars in 15 Galactic globular clusters and in the Large Magellanic Cloud (LMC) globular cluster Reticulum has been derived. It is based on accurate near-infrared (K) photometry combined with Two-Micron All-Sky Survey (2MASS) and other literature data. The PLK relation has been calibrated and compared with the previous empirical and theoretical determinations in literature. The zero point of the absolute calibration has been obtained from the K magnitude of RR Lyr whose distance modulus has been measured via trigonometric parallax with Hubble Space Telescope (HST). Using this relation, we obtain a distance modulus to the LMC of (m - M)0 = 18.54 +/- 0.15 mag, in good agreement with recent determinations based on the analysis of Cepheid variable stars. Based on observations collected at the European Southern Observatory within the observing programs 49.5-0021, 51.5-0024, 59.E-0340, 64.N-0038, 68.D-0287 and at the Telescopio Nazionale Galileo. E-mail: antonio.sollima@bo.astro.it (AS)

  18. mtDNA from the Early Bronze Age to the Roman Period Suggests a Genetic Link between the Indian Subcontinent and Mesopotamian Cradle of Civilization

    PubMed Central

    Witas, Henryk W.; Tomczyk, Jacek; Jędrychowska-Dańska, Krystyna; Chaubey, Gyaneshwer; Płoszaj, Tomasz

    2013-01-01

    Ancient DNA methodology was applied to analyse sequences extracted from freshly unearthed remains (teeth) of 4 individuals deeply deposited in slightly alkaline soil of the Tell Ashara (ancient Terqa) and Tell Masaikh (ancient Kar-Assurnasirpal) Syrian archaeological sites, both in the middle Euphrates valley. Dated to the period between 2.5 Kyrs BC and 0.5 Kyrs AD the studied individuals carried mtDNA haplotypes corresponding to the M4b1, M49 and/or M61 haplogroups, which are believed to have arisen in the area of the Indian subcontinent during the Upper Paleolithic and are absent in people living today in Syria. However, they are present in people inhabiting today’s Tibet, Himalayas, India and Pakistan. We anticipate that the analysed remains from Mesopotamia belonged to people with genetic affinity to the Indian subcontinent since the distribution of identified ancient haplotypes indicates solid link with populations from the region of South Asia-Tibet (Trans-Himalaya). They may have been descendants of migrants from much earlier times, spreading the clades of the macrohaplogroup M throughout Eurasia and founding regional Mesopotamian groups like that of Terqa or just merchants moving along trade routes passing near or through the region. None of the successfully identified nuclear alleles turned out to be ΔF508 CFTR, LCT-13910T or Δ32 CCR5. PMID:24040024

  19. mtDNA from the early Bronze Age to the Roman period suggests a genetic link between the Indian subcontinent and Mesopotamian cradle of civilization.

    PubMed

    Witas, Henryk W; Tomczyk, Jacek; Jędrychowska-Dańska, Krystyna; Chaubey, Gyaneshwer; Płoszaj, Tomasz

    2013-01-01

    Ancient DNA methodology was applied to analyse sequences extracted from freshly unearthed remains (teeth) of 4 individuals deeply deposited in slightly alkaline soil of the Tell Ashara (ancient Terqa) and Tell Masaikh (ancient Kar-Assurnasirpal) Syrian archaeological sites, both in the middle Euphrates valley. Dated to the period between 2.5 Kyrs BC and 0.5 Kyrs AD the studied individuals carried mtDNA haplotypes corresponding to the M4b1, M49 and/or M61 haplogroups, which are believed to have arisen in the area of the Indian subcontinent during the Upper Paleolithic and are absent in people living today in Syria. However, they are present in people inhabiting today's Tibet, Himalayas, India and Pakistan. We anticipate that the analysed remains from Mesopotamia belonged to people with genetic affinity to the Indian subcontinent since the distribution of identified ancient haplotypes indicates solid link with populations from the region of South Asia-Tibet (Trans-Himalaya). They may have been descendants of migrants from much earlier times, spreading the clades of the macrohaplogroup M throughout Eurasia and founding regional Mesopotamian groups like that of Terqa or just merchants moving along trade routes passing near or through the region. None of the successfully identified nuclear alleles turned out to be ΔF508 CFTR, LCT-13910T or Δ32 CCR5. PMID:24040024

  20. Dorsal Raphe Serotonin Neurons in Mice: Immature Hyperexcitability Transitions to Adult State during First Three Postnatal Weeks Suggesting Sensitive Period for Environmental Perturbation

    PubMed Central

    Rood, Benjamin D.; Calizo, Lyngine H.; Piel, David; Spangler, Zachary P.; Campbell, Kaitlin

    2014-01-01

    Trauma during early life is a major risk factor for the development of anxiety disorders and suggests that the developing brain may be particularly sensitive to perturbation. Increased vulnerability most likely involves altering neural circuits involved in emotional regulation. The role of serotonin in emotional regulation is well established, but little is known about the postnatal development of the raphe where serotonin is made. Using whole-cell patch-clamp recording and immunohistochemistry, we tested whether serotonin circuitry in the dorsal and median raphe was functionally mature during the first 3 postnatal weeks in mice. Serotonin neurons at postnatal day 4 (P4) were hyperexcitable. The increased excitability was due to depolarized resting membrane potential, increased resistance, increased firing rate, lack of 5-HT1A autoreceptor response, and lack of GABA synaptic activity. Over the next 2 weeks, membrane resistance decreased and resting membrane potential hyperpolarized due in part to potassium current activation. The 5-HT1A autoreceptor-mediated inhibition did not develop until P21. The frequency of spontaneous inhibitory and excitatory events increased as neurons extended and refined their dendritic arbor. Serotonin colocalized with vGlut3 at P4 as in adulthood, suggesting enhanced release of glutamate alongside enhanced serotonin release. Because serotonin affects circuit development in other brain regions, altering the developmental trajectory of serotonin neuron excitability and release could have many downstream consequences. We conclude that serotonin neuron structure and function change substantially during the first 3 weeks of life during which external stressors could potentially alter circuit formation. PMID:24695701

  1. Irregular, long-period boundary oscillations beyond approximately 100 R(sub e): GEOTAIL plasma observations

    NASA Technical Reports Server (NTRS)

    Siscoe, G. L.; Frank, L. A.; Ackerson, K. L.; Paterson, W. R.

    1994-01-01

    Near the tail boundary beyond about 100 Re, GEOTAIL often measures irregular, long-period oscillations in plasma velocity and density. Flow speed and density oscillate between magnetosheath values and values an order of magnitude less. The oscillations can persist for days. A typical oscillation lasts 100 minutes, but the range is large. The oscillations are highly asymmetric in that the increasing phase of the oscillation is an order of magnitude faster than the decreasing phase. This asymmetry shows that they are a distinct class of oscillations, not previously explicitly reported, and that they are not mere consequences of tail flapping in a variable solar wind. The changes in flow direction through an oscillation imply that the oscillation results from a motion of the boundary toward and away from the spacecraft with an amplitude between 5 and 10 R(sub e). A consideration of options suggests that the most plausible cause of these oscillations is the 'breathing' of the magnetotail that attends the substorm cycle.

  2. Concentric waves and short-period oscillations observed in the ionosphere after the 2013 Moore EF5 tornado

    NASA Astrophysics Data System (ADS)

    Nishioka, Michi; Tsugawa, Takuya; Kubota, Minoru; Ishii, Mamoru

    2013-11-01

    We detected clear concentric waves and short-period oscillations in the ionosphere after an Enhanced Fujita scale (EF)5 tornado hit Moore, Oklahoma, U.S., on 20 May 2013 using dense wide-coverage ionospheric total electron content (TEC) observations in North America. These concentric waves were nondispersive, with a horizontal wavelength of ~120 km and a period of ~13 min. They were observed for more than 7 h throughout North America. TEC oscillations with a period of ~4 min were also observed to the south of Moore for more than 8 h. A comparison between the TEC observations and infrared cloud image from the GOES satellite indicates that the concentric waves and short-period oscillations are caused by supercell-induced atmospheric gravity waves and acoustic resonances, respectively. This observational result provides the first clear evidence of a severe meteorological event causing atmospheric waves propagating upward in the upper atmosphere and reaching the ionosphere.

  3. Comparison of Columnar Water Vapor Measurements During The Fall 1997 ARM Intensive Observation Period: Optical Methods

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Michalsky, J.; Slater, D.; Barnard, J.; Halthore, R.; Liljegren, J.; Holben, B.; Eck, T.; Livingston, J.; Russell, P.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    In the fall of 1997 the Atmospheric Radiation Measurement (ARM program conducted an intensive Observation Period (IOP) to study water vapor at its Southern Great Plains (SGP) site. Among the large number of instruments, four sun-tracking radiometers were present to measure the columnar water vapor (CWV). All four solar radiometers retrieve CWV by measuring solar transmittance in the 0.94-micrometer water vapor absorption band. As one of the steps in the CWV retrievals the aerosol component is subtracted from the total transmittance, in the 0.94-micrometer band. The aerosol optical depth comparisons among the same four radiometers are presented elsewhere. We have used three different methods to retrieve CWV. Without attempting to standardize on the same radiative transfer model and its underlying water vapor spectroscopy we found the CWV to agree within 0.13 cm (rms) for CWV values ranging from 1 to 5 cm. Preliminary results obtained when using the same updated radiative transfer model with updated spectroscopy for all instruments will also be shown. Comparisons to the microwave radiometer results will be included in the comparisons.

  4. Weekly periodicities of aerosol properties observed at an urban location in India

    NASA Astrophysics Data System (ADS)

    Satheesh, S. K.; Vinoj, V.; Moorthy, K. Krishna

    2011-07-01

    Multi-year (~ 7 years) observations of aerosol optical and microphysical properties were conducted at a tropical urban location in Bangalore, India. As a consequence of rapid urbanization, Bangalore presents high local atmospheric emissions, which makes it an interesting site to study the effect of anthropogenic activities on aerosol properties. It has been found that both column (aerosol optical depth, AOD) and ground-level measurements (black carbon (BC) and composite aerosol mass) exhibit a weekly cycle with low aerosol concentrations on weekends. In comparison to the weekdays, the weekend reductions of aerosol optical depth, black carbon and composite aerosol mass concentrations were ~ 15%, 25% and 24%, respectively. The magnitude of weekend reduction of black carbon is as much as ~ 1 μg m - 3 . The similarity in the weekly cycle between the column and surface measurements suggests that the aerosol column loading at this location is governed by local anthropogenic emissions. The strongest weekly cycle in composite aerosol mass concentration was observed in the super micron mass range (> 1 μm). The weekly cycle of composite aerosol mass in the sub micron mass range (< 1 μm) was weak in comparison to the super micron aerosol mass.

  5. Weekly periodicities of aerosol properties observed at an urban location in India

    SciTech Connect

    Satheesh, S K; Vinoj, V; Moorthy, K Krishna

    2011-07-01

    Multi-year (~7 years) observations of aerosol optical and microphysical properties were conducted at a tropical urban location in Bangalore, India. As a consequence of rapid urbanization, Bangalore presents high local atmospheric emissions, which makes it an interesting site to study the effect of anthropogenic activities on aerosol properties. It has been found that both column (aerosol optical depth, AOD) and ground-level measurements (black carbon (BC) and composite aerosol mass) exhibit a weekly cycle with low aerosol concentrations on weekends. In comparison to the weekdays, the weekend reductions of aerosol optical depth, black carbon and composite aerosol mass concentrations were ~15%, 25% and 24%, respectively. The magnitude of weekend reduction of black carbon is as much as ~1 μg m-3. The similarity in the weekly cycle between the column and surface measurements suggests that the aerosol column loading at this location is governed by local anthropogenic emissions. The strongest weekly cycle in composite aerosol mass concentration was observed in the super micron mass range (>1 μm). The weekly cycle of composite aerosol mass in the sub micron mass range (<1 μm) was weak in comparison to the super micron aerosol mass.

  6. Observation of atomic ordering of triple-period-A and -B type in GaAsBi

    SciTech Connect

    Wu, Mingjian Luna, Esperanza; Trampert, Achim; Puustinen, Janne; Guina, Mircea

    2014-07-28

    We report the observation of atomic ordering of triple-period (TP)-A and -B type in low temperature (LT) grown GaAsBi alloy using transmission electron microscopy (TEM). In addition to previous reports, where only TP-A ordering was identified in III-V alloys, here, we confirm by electron diffraction, high-resolution (HR) TEM, and HR Z-contrast scanning TEM that two ordering variants coexists for LT-GaAsBi. We find that the TP-A ordering variant dominates over the TP-B variant. TP-A domains extend over 50–100 nm (projected lateral width) and are of higher perfection compared to TP-B domains. HR Z-contrast scanning TEM on different domains reveals a variation in the Bi occupancy in the (111) planes with triple period sequence. Since the formation of ordered phases has been directly linked to the occurrence of specific surface reconstructions, our results suggest a correlation between the TP-A and B type domains and the multiple stability of n × 3 and 3 × n reconstructions on the (001) surface of GaAsBi under low temperature growth.

  7. Tracing non-conservative mass transfer eras in close binaries from observed period variations

    NASA Astrophysics Data System (ADS)

    Nanouris, N.; Kalimeris, A.; Antonopoulou, E.; Rovithis-Livaniou, H.

    2013-09-01

    The pure information directly taken from the observed orbital evolution of eclipsing binary stars (centuries at most) is valuable for the study of many important physical mechanisms related to the stellar structure. Especially in the case of eclipsing binary systems, this may happen by monitoring their eclipse timing variations, i.e. by means of an O-C diagram analysis. As long as a binary system attains a semi-detached configuration, material begins to flow from the component that fills its Roche lobe toward its mate through the first Lagrangian (L1) point. Here, we examine two non conservative mass transfer (MT) paths. The MT process is then accompanied by mass and angular momentum loss from the system. In the first path, angular momentum is removed through a hot spot which re-emits part of the incoming material, and in the second, angular momentum is carried away via an outer Lagrangian point (L2/L3) due to the small accumulating efficiency of the accretion disk surrounding the gainer. Dealing with the less massive component as the donor in the latter path, it is shown that there is always a critical mass ratio over which the period is expected to decrease, contrary to what the fully conservative MT predicts. Consistent with our expectations, the critical values become progressively smaller as the degree of liberalism is gradually widened. The O-C diagram of several semi-detached systems, expecting to experience a liberal era, is individually examined aiming to estimate both the mass transfer and the mass loss rate.

  8. [Observational study of black carbon aerosol during straw-burning period].

    PubMed

    Wu, De-xia; Wei, Qing-nong; Wei, Jian-li; Liu, Shi-sheng; Feng, Wei-wei

    2008-12-01

    Black carbon aerosol (BC) has been measured at three sites in Hefei City during May and June, 2007. Analyzing these real-time BC data, the concentration characters and the sources of black carbon aerosol can be found. The average concentrations of BC in normal period and straw-burning period are 4.85 microg/m3 and 8.38 microg/m3, respectively. The significant difference shows that the straw-burning is one of the main sources. The correlation coefficients between daily average concentration of BC and PM10 is 0.74, while the values of BC/PM10 in normal period and straw-burning period are 4.7% and 7.9%, respectively. Through comparing to the BC concentration during straw-burning period in 2004, the results indicated that pollution of BC has reduced after straw-burning was forbidden by the government. PMID:19256359

  9. Statistical tests of peaks and periodicities in the observed redshift distribution of quasi-stellar objects

    NASA Astrophysics Data System (ADS)

    Duari, Debiprosad; Gupta, Patrick D.; Narlikar, Jayant V.

    1992-01-01

    An overview of statistical tests of peaks and periodicities in the redshift distribution of quasi-stellar objects is presented. The tests include the power-spectrum analysis carried out by Burbidge and O'Dell (1972), the generalized Rayleigh test, the Kolmogorov-Smirnov test, and the 'comb-tooth' test. The tests reveal moderate to strong evidence for periodicities of 0.0565 and 0.0127-0.0129. The confidence level of the periodicity of 0.0565 in fact marginally increases when redshifts are transformed to the Galactocentric frame. The same periodicity, first noticed in 1968, persists to date with a QSO population that has since grown about 30 times its original size. The prima facie evidence for periodicities in 1n(1 + z) is found to be of no great significance.

  10. Diurnal-period currents trapped above Fieberling Guyot: observed characteristics and model comparisons

    USGS Publications Warehouse

    Noble, M.A.; Brink, K.H.; Eriksen, C.C.

    1994-01-01

    Current measurements at depths of 19, 115, 264 and 464 m above the summit of Fieberling Guyot (32??28???N, 127??47???W) for 13 months in 1989 show that the diurnal tides are strongly amplified. The measured variances for K1, P1 and O1 at the 115 m depth were 810, 140 and 80 times larger than the variances of the respective estimated barotropic tides. The diurnal currents closer to the summit were also strongly amplified, through the variance ratios were 40-50% of the ratios observed at 115 m. The diurnal band currents were only amplified at the precise tidal frequencies; the bandwidth of the response was less than 0.0002 cph. The discrete character of the response suggests that only currents with large spatial scales will be amplified. The characteristics of the amplified diurnal currents are compared to those predicted by a model for Fieberling Guyot of seamount-trapped waves driven by the barotropic tide. The amplitudes of the responses at this one site on the seamount compare favourably to the predicted. ?? 1994.

  11. Rotation periods and seismic ages of KOIs - comparison with stars without detected planets from Kepler observations

    NASA Astrophysics Data System (ADS)

    Ceillier, T.; van Saders, J.; García, R. A.; Metcalfe, T. S.; Creevey, O.; Mathis, S.; Mathur, S.; Pinsonneault, M. H.; Salabert, D.; Tayar, J.

    2016-02-01

    One of the most difficult properties to derive for stars is their age. For cool main-sequence stars, gyrochronology relations can be used to infer stellar ages from measured rotation periods and Hertzsprung Russell diagram positions. These relations have few calibrators with known ages for old, long rotation period stars. There is a significant sample of old Kepler objects of interest, or KOIs, which have both measurable surface rotation periods and precise asteroseismic measurements from which ages can be accurately derived. In this work, we determine the age and the rotation period of solar-like pulsating KOIs to both compare the rotation properties of stars with and without known planets and enlarge the gyrochronology calibration sample for old stars. We use Kepler photometric light curves to derive the stellar surface rotation periods while ages are obtained with asteroseismology using the Asteroseismic Modelling Portal in which individual mode frequencies are combined with high-resolution spectroscopic parameters. We thus determine surface rotation periods and ages for 11 planet-hosting stars, all over 2 Gyr old. We find that the planet-hosting stars exhibit a rotational behaviour that is consistent with the latest age-rotation models and similar to the rotational behaviour of stars without detected planets. We conclude that these old KOIs can be used to test and calibrate gyrochronology along with stars not known to host planets.

  12. Overview of the Dust and Biomass-burning Experiment and African Monsoon Multidisciplinary Analysis Special Observing Period-0

    NASA Astrophysics Data System (ADS)

    Haywood, J. M.; Pelon, J.; Formenti, P.; Bharmal, N.; Brooks, M.; Capes, G.; Chazette, P.; Chou, C.; Christopher, S.; Coe, H.; Cuesta, J.; Derimian, Y.; Desboeufs, K.; Greed, G.; Harrison, M.; Heese, B.; Highwood, E. J.; Johnson, B.; Mallet, M.; Marticorena, B.; Marsham, J.; Milton, S.; Myhre, G.; Osborne, S. R.; Parker, D. J.; Rajot, J.-L.; Schulz, M.; Slingo, A.; Tanré, D.; Tulet, P.

    2008-12-01

    The African Monsoon Multidisciplinary Analysis (AMMA) is a major international campaign investigating far-reaching aspects of the African monsoon, climate and the hydrological cycle. A special observing period was established for the dry season (SOP0) with a focus on aerosol and radiation measurements. SOP0 took place during January and February 2006 and involved several ground-based measurement sites across west Africa. These were augmented by aircraft measurements made by the Facility for Airborne Atmospheric Measurements (FAAM) aircraft during the Dust and Biomass-burning Experiment (DABEX), measurements from an ultralight aircraft, and dedicated modeling efforts. We provide an overview of these measurement and modeling studies together with an analysis of the meteorological conditions that determined the aerosol transport and link the results together to provide a balanced synthesis. The biomass burning aerosol was significantly more absorbing than that measured in other areas and, unlike industrial areas, the ratio of excess carbon monoxide to organic carbon was invariant, which may be owing to interaction between the organic carbon and mineral dust aerosol. The mineral dust aerosol in situ filter measurements close to Niamey reveals very little absorption, while other measurements and remote sensing inversions suggest significantly more absorption. The influence of both mineral dust and biomass burning aerosol on the radiation budget is significant throughout the period, implying that meteorological models should include their radiative effects for accurate weather forecasts and climate simulations. Generally, the operational meteorological models that simulate the production and transport of mineral dust show skill at lead times of 5 days or more. Climate models that need to accurately simulate the vertical profiles of both anthropogenic and natural aerosols to accurately represent the direct and indirect effects of aerosols appear to do a reasonable job

  13. How the Initial Thinking Period Affects Student Argumentation during Peer Instruction: Students' Experiences versus Observations

    ERIC Educational Resources Information Center

    Nielsen, Kjetil L.; Hansen, Gabrielle; Stav, John B.

    2016-01-01

    The authors have compared students discussing multiple-choice quizzes during peer instruction with and without the initial thinking period before discussion. Video clips of students engaged in peer discussion in groups of three of varying group combinations, a total of 140 different students in all, were compared to students' own experiences…

  14. IUE observations of periodic comets Tempel-2, Kopff, and Tempel-1

    NASA Technical Reports Server (NTRS)

    Feldman, Paul D.; Festou, Michel C.

    1992-01-01

    We summarize the results of observations made between 10 Jun. - 18 Dec. 1988 with the International Ultraviolet Explorer (IUS) of comet P/Tempel-2 during its 1988 appearance. The derived water production rate and relative gas/dust ratio are compared with those of P/Halley, observed with IUE in 1985-86, and other potential Comet Rendezvous/Asteroid Flyby (CRAF) target comets, P/Kopff and P/Tempel-1, both observed with IUE in 1983.

  15. Estimating the period and Q of the Chandler Wobble from observations and models of its excitation (Abstract)

    NASA Astrophysics Data System (ADS)

    Gross, R.; Nastula, J.

    2015-08-01

    Any irregularly shaped solid body rotating about some axis that is not aligned with its figure axis will freely wobble as it rotates. For the Earth, this free wobble is known as the Chandler wobble in honor of S.C. Chandler, Jr. who first observed it in 1891. Unlike the forced wobbles of the Earth, such as the annual wobble, whose periods are the same as the periods of the forcing mechanisms, the period of the free Chandler wobble is a function of the internal structure and rheology of the Earth, and its decay time constant, or quality factor Q, is a function of the dissipation mechanism(s), like mantle anelasticity, that are acting to dampen it. Improved estimates of the period and Q of the Chandler wobble can therefore be used to improve our understanding of these properties of the Earth. Here, estimates of the period and Q of the Chandler wobble are obtained by finding those values that minimize the power within the Chandler band of the difference between observed and modeled polar motion excitation spanning 1962- 2010. Atmosphere, ocean, and hydrology models are used to model the excitation caused by both mass and motion variations within these global geophysical fluids. Direct observations of the excitation caused by mass variations as determined from GRACE time varying gravitational field measurements are also used. The resulting estimates of the period and Q of the Chandler wobble will be presented along with a discussion of the robustness of the estimates.

  16. Observation of self-assembled periodic nano-structures induced by femtosecond laser in both ablation and deposition regimes

    NASA Astrophysics Data System (ADS)

    Tang, Mingzhen; Zhang, Haitao; Her, Tsing-Hua

    2008-02-01

    We observed the spontaneous formation of periodic nano-structures in both femtosecond laser ablation and deposition. The former involved 400-nm femtosecond pulses from a 250-KHz regenerated amplified mode-locked Ti:sapphire laser and periodic nanocracks and the nano-structure are in the form of periodic nanocracks in the substrate, the latter applied an 80-MHz mode-locked Ti:sapphire oscillator with pulse energy less than half nanojoule in a laser-induced chemical vapor deposition configuration and tungsten nanogratings grow heterogeneously on top of the substrates. These two observed periodic nanostructures have opposite orientations respecting to laser polarization: the periodic nanocracks are perpendicular to, whereas the deposited tungsten nanogratings are parallel to laser polarization direction. By translating the substrate respecting to the laser focus, both the periodic nanocrack and tungsten nanograting extend to the whole scanning range. The deposited tungsten nanogratings possess excellent uniformity on both the grating period and tooth length. Both the attributes can be tuned precisely by controlling the laser power and scanning speed. Furthermore, we discovered that the teeth of transverse tungsten nanogratings are self aligned along their axial direction during multiple scanning with appropriate offset between scans. We demonstrate the feasibility of fabricating large-area one-dimensional grating by exploiting such unique property. These distinct phenomena of nanocracks and tungsten nanogratings indicate different responsible mechanisms.

  17. Whole earth telescope observations of the white dwarf G29-38 - Phase variations of the 615 second period

    NASA Technical Reports Server (NTRS)

    Winget, D. E.; Nather, R. E.; Clemens, J. C.; Provencal, J.; Kleinman, S. J.; Bradley, P. A.; Wood, M. A.; Claver, C. F.; Robinson, E. L.; Hine, B. P.

    1990-01-01

    An extensive set of high-speed photometric observations obtained with the Whole Earth Telescope network is used to show that the complex light curve of the ZZ Zeti (DAV) star G29-38 is dominated by a single, constant amplitude period of 615 s during the time span of these observations. The pulse arrival times for this period exhibit a systematic variation in phase readily explained by light-travel time effects produced by reflex orbital motion about an unseen companion. The best-fit model to the observations indicates a highly eccentric orbit, a period of 109 + or - 13 days and a minimum mass of 0.5 solar mass for the companion.

  18. Whole earth telescope observations of the white dwarf G29-38 - Phase variations of the 615 second period

    SciTech Connect

    Winget, D.E.; Nather, R.E.; Clemens, J.C.; Provencal, J.; Kleinman, S.J.; Bradley, P.A.; Wood, M.A.; Claver, C.F.; Robinson, E.L.; Hine, B.P. NASA, Ames Research Center, Moffett Field, CA )

    1990-07-01

    An extensive set of high-speed photometric observations obtained with the Whole Earth Telescope network is used to show that the complex light curve of the ZZ Zeti (DAV) star G29-38 is dominated by a single, constant amplitude period of 615 s during the time span of these observations. The pulse arrival times for this period exhibit a systematic variation in phase readily explained by light-travel time effects produced by reflex orbital motion about an unseen companion. The best-fit model to the observations indicates a highly eccentric orbit, a period of 109 + or - 13 days and a minimum mass of 0.5 solar mass for the companion. 23 refs.

  19. Study on workloads of human care worker with the introduction of IT system - the characteristics of work loads by observational research and the suggestions for KAIZEN.

    PubMed

    Mizuno, Yuki; Yoshikawa, Toru; Matsuda, Fumiko; Takeuchi, Yuriko; Motegi, Nobuyuki; Ikegami, Thor; Sakai, Kazuhiro

    2012-01-01

    The purpose of this study was to clarify the characteristic of workloads on human care worker with the introduction of IT system, and suggested the support measures for KAIZEN in Japan. The investigation method is workflow line and hearing with a focus on work observation. The objects were 8 human care workers of the acute hospital that introduced an electronic system. By the introduction of the electronic chart, the nurse station sojourn time decreased, sickroom sojourn time increased, and time about direct nursing care to a patient increased. In addition, access to patient information became easy, and the offer of the health care service based on correct information came to be possible in real time. By The point of workflow line, it was effect that moving lengths decreased in order to install the electronic chart in patients' rooms. Though, it was a problem that it hasn't formed where to place the instruments such as sphygmomanometer, clinical thermometer and others. PMID:22317644

  20. Data Assimilation Office (DAO) Operational Analyses and Reanalyses for Coordinated Enhanced Observing Period (CEOP)

    NASA Technical Reports Server (NTRS)

    Bosilovich, M.

    2003-01-01

    The DAO operational assimilation system has produced and archived gridded data since 1998, and will continue through the CEOP period. However, major system upgrades and new assimilation variables will significantly affect the surface energy balance and data product. These changes will be discussed and the prospects for a CEOP reanalysis will be presented. W e will also review the data currently available and describe how to access the data.

  1. Variation of Acoustic Cutoff Period with Height in the Solar Atmosphere: Theory versus Observations

    NASA Astrophysics Data System (ADS)

    Murawski, K.; Musielak, Z. E.; Konkol, P.; Wiśniewska, A.

    2016-08-01

    Recently Wiśniewska et al. demonstrated observationally how the acoustic cutoff frequency varies with height in the solar atmosphere including the upper photosphere and the lower and middle chromosphere, and showed that the observational results cannot be accounted for by the existing theoretical formulas for the acoustic cutoff. In order to reproduce the observed variation of the cutoff with atmospheric height, numerical simulations of impulsively generated acoustic waves in the solar atmosphere are performed, and the spectral analysis of temporal wave profiles is used to compute numerically changes of the acoustic cutoff with height. Comparison of the numerical results with the observational data shows good agreement, which clearly indicates that the obtained results may be used to determine the structure of the background solar atmosphere.

  2. Entrainment in solution of an oscillating NADH oxidase activity from the bovine milk fat globule membrane with a temperature-compensated period length suggestive of an ultradian time-keeping (clock) function

    NASA Technical Reports Server (NTRS)

    Morre, D. James; Lawler, Juliana; Wang, Sui; Keenan, Thomas W.; Morre, Dorothy M.

    2002-01-01

    Entrainment in solution of an oscillating activity with a temperature compensated period of 24 min is described for a NADH oxidase (NOX) activity of the bovine milk fat globule membrane, a derivative of the mammary epithelial cell plasma membrane. The period of 24 min remained unchanged at 17 degrees C, 27 degrees C and 37 degrees C whereas the amplitude approximately doubled with each 10 degree C rise in temperature (Q(10)congruent with 2). The periodicity was observed with both intact milk fat globule membranes and with detergent-solubilized membranes, demonstrating that the oscillations did not require an association with membranes. The periodicity was not the result of instrument variation or of chemical interactions among reactants in solution. Preparations with different periodicities entrained (autosynchronized) when mixed. Upon mixing, the preparations exhibited two oscillatory patterns but eventually a single pattern representing the mean of the farthest separated maxima of the two preparations analyzed separately emerged. The cell surface NOX protein is the first reported example of an entrainable biochemical entity with a temperature-compensated periodicity potentially capable of functioning as an ultradian or circadian clock driver.

  3. Detecting non-sinusoidal periodicities in observational data using multiharmonic periodograms

    NASA Astrophysics Data System (ADS)

    Baluev, Roman V.

    2009-05-01

    We address the problem of assessing the statistical significance of candidate periodicities found using the so-called `multiharmonic' periodogram, which is being used for detection of non-sinusoidal signals and is based on the least-squares fitting of truncated Fourier series. The recent author's investigation made for the Lomb-Scargle periodogram is extended to the more general multiharmonic periodogram. As a result, closed and efficient analytic approximations to the false alarm probability, associated with multiharmonic periodogram peaks, are obtained. The resulting analytic approximations are tested under various conditions using Monte Carlo simulations. The simulations showed a nice precision and robustness of these approximations.

  4. GUVI observations of the airglow response to solar flares: Results from the CAWSES campaign period

    NASA Astrophysics Data System (ADS)

    Wolven, B. C.; Paxton, L. J.; Morrison, D.

    2006-05-01

    GUVI limb and disk observations of oxygen and nitrogen airglow emissions show strong variability during solar events; both the intensity and the altitude of peak limb emission vary in response to the brightened and hardened solar spectrum. We present the observed response, and compare it to model predictions generated using a flare-type solar input spectrum. We examine the difference in atmospheric response to consecutive flare events, owing to the modification of thermospheric density and composition by the initial flare and subsequent geomagnetic disturbances.

  5. Observations and modeling of northern mid-latitude recurring slope lineae (RSL) suggest recharge by a present-day martian briny aquifer

    NASA Astrophysics Data System (ADS)

    Stillman, David E.; Michaels, Timothy I.; Grimm, Robert E.; Hanley, Jennifer

    2016-02-01

    Recurring slope lineae (RSL) are narrow (0.5-5 m) dark features on Mars that incrementally lengthen down steep slopes, fade in colder seasons, and recur annually. These features have been identified from the northern to southern mid-latitudes. Here, we describe how observations of northern mid-latitude RSL in northern Chryse Planitia and southwestern Acidalia Planitia (CAP) suggest that brines start flowing before northern spring equinox and continue for more than half a Mars-year (490 ± 40 sols, spanning solar longitude 337° ± 11°-224° ± 20°). All CAP RSL are found on the steep slopes of craters and their source zones are at or below the elevation of the surrounding plains. Spacecraft-derived surface temperature observations cannot resolve individual RSL, so thermal modeling was used to determine that CAP RSL have a freezing temperature of 238-252 K, freeze and melt diurnally, and flow only occurs within the top ∼8 cm of the regolith. Furthermore, we calculate that a typical CAP RSL has a water budget of 1.5-5.6 m3/m of headwall. Therefore, such a large water budget makes annual recharge via atmospheric or subsurface diffusion sources unlikely. Alternatively, we hypothesize that the most plausible RSL source is a briny aquifer with a freezing temperature less than or equal to the mean annual CAP surface temperature (220-225 K). The annual cycle is as follows: in late autumn, the shallowest part of the brine feeding the source zone freezes, forming an ice dam. As spring approaches, temperatures rise and the dam is breached. Brine is discharged and the RSL initially lengthens rapidly (>1.86 m/sol), the lengthening rate then slows considerably, to ∼0.25 m/sol. Eventually, the losses equal the discharge rate and the RSL reaches its equilibrium phase. As brine flows in the RSL some of the water is lost to the atmosphere, therefore the freezing temperature of the brine within the RSL is higher (238-252 K) as the brine transitions to a super-eutectic salt

  6. African Monsoon Multidisciplinary Analysis (AMMA) : The Special Observing Period of 2006

    NASA Astrophysics Data System (ADS)

    Polcher, J.; Cairo, F.; Fierli, F.; Höller, H.; Law, K.; Mari, C.; Reeves, C.; Schlager, H.

    2006-12-01

    The AMMA project aims at enhancing our understanding of the West African monsoon and its underlying physical, chemical and biological processes. This enhanced knowledge of the processes involved in the establishment and variability of the monsoon will be used to improve our capacity to predict it and evaluate the impacts on land-productivity, management of water resources and public health. The objective is to provide societies in Africa with improved tools to manage their dependence on environmental conditions. In the framework of AMMA a dense observational network has been established both as routine and campaign- based facilities. The aim is to provide a complete picture of the physical, chemical and biological processes over the ocean, the continent and in the atmosphere. The base network has been established over the last few year and covers surface states and surface flux monitoring in a number catchments over the climatic gradient of the region. The upper-air sounding network was upgraded and enhanced to improve the data available for operational weather forecasting. During 2006 AMMA supported a large field campaign to cover the dry season (SOP0), the monsoon onset (SOP1) and the wet season (SOP2). The enhancement to the observing system in 2006 included balloon borne instruments, a lightning network over northern Benin, 3 research vessels and 5 research aircraft stationed in the Niamey and Ouagadougou. Most of SOP2 observations were dedicated to the intense mesoscale convective systems which are generated in the region and travel to the West. Their impact on the circulation in the troposphere and lower stratosphere, the water cycle in the region and the transport of trace gases and aerosols have been observed at different stages of the life cycle of these systems. This talk will provide a overview of the AMMA project and the observations carried out in 2006, focusing on the most relevant events.

  7. VLBI Observations of the Shortest Orbital Period Black Hole X-Ray Binary

    NASA Astrophysics Data System (ADS)

    Paragi, Zsolt; Belloni, Tomaso M.; van der Horst, Alexander J.; Miller-Jones, James

    The X-ray transient MAXI J1659-152 was discovered by Swift/BAT and it was initially identified as a GRB. Soon its Galactic origin and binary nature were established. There exists a wealth of multi-wavelength monitoring data for this source, providing a great coverage of the full X-ray transition in this candidate black hole binary system. We obtained two epochs of EVN/e-VLBI and four epochs of VLBA data of MAXI J1659-152 which show evidence for some extended emission in the early phases but -against expectations- no major collimated ejecta during the accretion disk state transition. This might be related to the fact that, with a red dwarf donor star, MAXI J1659-152 is the shortest orbital period black hole X-ray binary system.

  8. Daytime Raman lidar measurements of water vapor during the ARM 1997 water vapor intensive observation period

    SciTech Connect

    Turner, D.D.; Goldsmith, J.E.M.

    1998-04-01

    Because of the importance of water vapor, the ARM program initiated a series of three intensive operating periods (IOPs) at its CART (Cloud And Radiation Testbed) site. The goal of these IOPs is to improve and validate the state-of-the-art capabilities in measuring water vapor. To date, two of the planned three IOPs have occurred: the first was in September of 1996, with an emphasis on the lowest kilometer, while the second was conducted from September--October 1997 with a focus on both the upper troposphere and lowest kilometer. These IOPs provided an excellent opportunity to compare measurements from other systems with those made by the CART Raman lidar. This paper addresses primarily the daytime water vapor measurements made by the lidar system during the second of these IOPs.

  9. On the periodicity of symbolic observations of piecewise smooth discrete-time systems

    NASA Technical Reports Server (NTRS)

    Ramadge, Peter J.

    1990-01-01

    A study is made of the behavior of discrete-time systems composed of a set of smooth transition maps coupled by a quantized feedback function. The feedback function partitions the state space into disjoint regions and assigns a smooth transition function to each region. The main result is that under a constraint on the norm of the derivative of the transition maps, a bounded state trajectory with limit points in the interior of the switching regions leads to a region index sequence that is eventually periodic. Under these assumptions, it is shown that eventually the feedback function is determined by a finite state automaton. A similar result is proved in the case of finite state dynamic feedback.

  10. A single administration of methamphetamine to mice early in the light period decreases running wheel activity observed during the dark period.

    PubMed

    Kitanaka, Nobue; Kitanaka, Junichi; Hall, F Scott; Uhl, George R; Watabe, Kaname; Kubo, Hitoshi; Takahashi, Hitoshi; Tatsuta, Tomohiro; Morita, Yoshio; Takemura, Motohiko

    2012-01-01

    Repeated intermittent administration of amphetamines acutely increases appetitive and consummatory aspects of motivated behaviors as well as general activity and exploratory behavior, including voluntary running wheel activity. Subsequently, if the drug is withdrawn, the frequency of these behaviors decreases, which is thought to be indicative of dysphoric symptoms associated with amphetamine withdrawal. Such decreases may be observed after chronic treatment or even after single drug administrations. In the present study, the effect of acute methamphetamine (METH) on running wheel activity, horizontal locomotion, appetitive behavior (food access), and consummatory behavior (food and water intake) was investigated in mice. A multi-configuration behavior apparatus designed to monitor the five behaviors was developed, where combined measures were recorded simultaneously. In the first experiment, naïve male ICR mice showed gradually increasing running wheel activity over three consecutive days after exposure to a running wheel, while mice without a running wheel showed gradually decreasing horizontal locomotion, consistent with running wheel activity being a positively motivated form of natural motor activity. In experiment 2, increased horizontal locomotion and food access, and decreased food intake, were observed for the initial 3h after acute METH challenge. Subsequently, during the dark phase period decreased running wheel activity and horizontal locomotion were observed. The reductions in running wheel activity and horizontal locomotion may be indicative of reduced dopaminergic function, although it remains to be seen if these changes may be more pronounced after more prolonged METH treatments. PMID:22079320

  11. Observations on the long-period variability of the Gulf Stream downstream of Cape Hatteras

    NASA Technical Reports Server (NTRS)

    Vazquez, Jorge

    1993-01-01

    To examine the long-period variability of the Gulf Stream, sea level residuals relative to a 2-year mean sea level in the Gulf Stream downstream of Cape Hatteras (between 75 deg W and 60 deg W longitude) are used. Residuals, as derived from Geosat altimetry between November 1986 and December 1988, were gridded in space and time at a temporal resolution of 10 days and spatial resolution of 1/4 deg. Complex empirical orthogonal function (CEOF) analysis was applied to the data set to extract the spatially correlated signal with the original data subsampled to 1/2 deg. In addition to determining the space-time scales and propagation characterisitics of the different modes, wavenumber-frequency spectral techniques were used to separate the variability into propagating and stationary components. The CEOF technique applied to the data set indicated that the first four CEOF modes accounted for 60% of the variability and were found to be above the noise leve 99% of the time. CEOF 1 was associated with westward propagation at 5 km/d at a wavelength of 2000 km and eastward propagation at 1-2 km/d centered at a 500-km wavelength. This first CEOF is in good agreement with thin-jet equivalent barotropic models which predict westward propagation for wavelengths greater than 1130 km. A deflection of the wavelike pattern at 65 deg W also indicates a possible topographic effect. A simple scaling of the effect of topography indicates that for length scales longer than the internal Rossby radius of deformation, the topographic term is at least of the same order of magnitude as the beta effect. The second CEOF was more broadbanded in wavenumber space, with eastward propagation occurring in a wavenumber-frequency band between 300 and 1400 km and 0.5 and 2.0 cycles/yr. The third CEOF is similar in structure to the first, but with less energy. CEOF 4 was clearly identifiable with higher frequencies than the first three with westward propagation at 4 km/d. The spatial location of this mode

  12. Period variations in pulsating X-ray sources. I - Accretion flow parameters and neutron star structure from timing observations

    NASA Technical Reports Server (NTRS)

    Lamb, F. K.; Shaham, J.; Pines, D.

    1978-01-01

    Torque fluctuations which can lead to variations in the periods of pulsating X-ray sources are examined. A description of torque variations in terms of noise processes is developed, and the resulting noise models are applied to observations of several pulsating X-ray sources. It is shown that fluctuations in accretion torque could account for the observed period variations and spindown episodes in Her X-1 and Cen X-3. The values of the torque noise strengths inferred from either a nonresonant response or, in the case of Her X-1, a Tkachenko-mode interpretation of the data are found to be consistent with those expected from processes at the magnetospheric boundary of an accreting neutron star. Ways to distinguish among the various interpretations of the period variations are considered. It is noted that fluctuating mass-flow rates may be responsible for other phenomena observed in compact X-ray sources, such as wobble with zero initial amplitude and binary period variations in close binary systems experiencing mass transfer.

  13. Long-Term Satellite Observations of Microcystin Concentrations in Lake Taihu during Cyanobacterial Bloom Periods.

    PubMed

    Shi, Kun; Zhang, Yunlin; Xu, Hai; Zhu, Guangwei; Qin, Boqiang; Huang, Changchun; Liu, Xiaohan; Zhou, Yongqiang; Lv, Heng

    2015-06-01

    Microcystins (MCs) produced by cyanobacteria pose a serious threat to public health. Intelligence on MCs distributions in freshwater is therefore critical for environmental agencies, water authorities, and public health organizations. We developed and validated an empirical model to quantify MCs in Lake Taihu during cyanobacterial bloom periods using the atmospherically Rayleigh-corrected moderate resolution imaging spectroradiometer (MODIS-Aqua) (Rrc) products and in situ data by means of chlorophyll a concentrations (Chla). First, robust relationships were constructed between MCs and Chla (r = 0.91; p < 0.001; t-test) and between Chla and a spectral index derived from Rrc (r = -0.86; p < 0.05; t-test). Then, a regional algorithm to analyze MCs in Lake Taihu was constructed by combining the two relationships. The model was validated and then applied to an 11-year series of MODIS-Aqua data to investigate the spatial and temporal distributions of MCs. MCs in the lake were markedly variable both spatially and temporally. Cyanobacterial bloom scums, temperature, wind, and light conditions probably affected the temporal and spatial distribution of MCs in Lake Taihu. The findings demonstrate that remote sensing reconnaissance in conjunction with in situ monitoring can greatly aid MCs assessment in freshwater. PMID:25936388

  14. Two types of ion energy dispersions observed in the nightside auroral regions during geomagnetically disturbed periods

    NASA Astrophysics Data System (ADS)

    Hirahara, M.; Mukai, T.; Nagai, T.; Kaya, N.; Hayakawa, H.; Fukunishi, H.

    1996-04-01

    The Akebono satellite has observed two types of energy dispersion signatures of discrete ion precipitation event in the nightside auroral regions during active geomagnetic conditions. The charged particle experiments and electric and magnetic field detectors on board Akebono provide us with essential clues to characterize the source regions and acceleration and/or injection processes associated with these two types of ion signatures. The magnetic field data obtained simultaneously by the geosynchronous GOES 6 and 7 satellites and the ground magnetograms are useful to examine their relationships with geomagnetic activity. Mass composition data and pitch angle distributions show that different sources and processes should be attributed to two types (Types I and II) of energy dispersion phenomena. Type I consists of multiple bouncing ion clusters constituted by H+. These H+ clusters tend to be detected at the expansion phase of substorms and have characteristic multiple energy-dispersed signatures. Type II consists of O+ energy dispersion(s), which is often observed at the recovery phase. It is reasonable to consider that the H+ clusters of Type I are accelerated by dipolarization at the equator, are injected in the field-aligned direction, and bounce on closed field lines after the substorm onset. We interpret these multiple energy dispersion events as mainly due to the time-of-flight (TOF) effect, although the convection may influence the energy-dispersed traces. Based of the TOF model, we estimate the source distance to be 20-30 RE along the field lines. On the other hand, the O+ energy dispersion of Type II is a consequence of reprecipitation of terrestrial ions ejected as an upward flowing ion (UFI) beam from the upper ionosphere by a parallel electrostatic potential difference. The O+ energy dispersion is induced by the E×B drift during the field-aligned transport from the source region to the observation point.

  15. Suzaku And Multi-Wavelength Observations of OJ 287 During the Periodic Optical Outburst in 2007

    SciTech Connect

    Seta, Hiromi; Isobe, N.; Tashiro, Makoto S.; Yaji, Yuichi; Arai, Akira; Fukuhara, Masayuki; Kohno, Kotaro; Nakanishi, Koichiro; Sasada, Mahito; Shimajiri, Yoshito; Tosaki, Tomoka; Uemura, Makoto; Anderhub, Hans; Antonelli, L.A.; Antoranz, Pedro; Backes, Michael; Baixeras, Carmen; Balestra, Silvia; Barrio, Juan Abel; Bastieri, Denis; Becerra Gonzalez, Josefa; /IAC, La Laguna /Dortmund U. /Lodz U. /Lodz U. /DESY /Zurich, ETH /Munich, Max Planck Inst. /Padua U. /INFN, Padua /Siena U. /INFN, Siena /Barcelona, IEEC /Munich, Max Planck Inst. /Barcelona, IEEC /Madrid U. /Zurich, ETH /Wurzburg U. /Zurich, ETH /Madrid U. /Munich, Max Planck Inst. /Zurich, ETH /Madrid U. /Barcelona, IFAE /IAC, La Laguna /Laguna U., Tenerife /INFN, Rome /Dortmund U. /Udine U. /INFN, Udine /INFN, Padua /Udine U. /INFN, Udine /Barcelona, IEEC /Madrid U. /Udine U. /INFN, Udine /Udine U. /INFN, Udine /Udine U. /INFN, Udine /IAC, La Laguna /Madrid, CIEMAT /Sierra Nevada Observ. /Zurich, ETH /Padua U. /INFN, Padua /Wurzburg U. /Barcelona, IFAE /UC, Davis /Barcelona, IFAE /Barcelona, IFAE /Madrid U. /Barcelona, Autonoma U. /Munich, Max Planck Inst. /IAC, La Laguna /Laguna U., Tenerife /Barcelona, IFAE /IAC, La Laguna /Munich, Max Planck Inst. /Barcelona, Autonoma U. /Munich, Max Planck Inst. /SLAC /IAC, La Laguna /Laguna U., Tenerife /Zurich, ETH /Wurzburg U. /Munich, Max Planck Inst. /Munich, Max Planck Inst. /Munich, Max Planck Inst. /Zurich, ETH /INFN, Rome /UC, Davis /Siena U. /INFN, Siena /Turku U. /Padua U. /INFN, Padua /Udine U. /INFN, Udine /Padua U. /INFN, Padua /Zurich, ETH /Munich, Max Planck Inst. /DESY /Sofiya, Inst. Nucl. Res. /Udine U. /INFN, Udine /Wurzburg U. /INFN, Rome /Padua U. /INFN, Padua /Barcelona, IFAE /Barcelona, IFAE /Siena U. /INFN, Siena /Wurzburg U. /Madrid U. /Munich, Max Planck Inst. /Munich, Max Planck Inst. /Barcelona, IEEC /Sierra Nevada Observ. /Barcelona, IFAE /Madrid U. /Turku U. /Munich, Max Planck Inst. /Munich, Max Planck Inst. /UC, Santa Cruz /Madrid U. /Siena U. /INFN, Siena /Barcelona, IEEC /Turku U. /Padua U. /INFN, Padua /Zurich, ETH /Siena U. /INFN, Siena /Sierra Nevada Observ. /Udine U. /INFN, Udine /INFN, Trieste /Padua U. /INFN, Padua /Sierra Nevada Observ. /Padua U. /INFN, Padua /Barcelona, IFAE /Barcelona, IFAE /Dortmund U. /Barcelona, IEEC /ICREA, Barcelona /Barcelona, IFAE /Zurich, ETH /Barcelona, Autonoma U. /Wurzburg U. /Padua U. /INFN, Padua /Munich, Max Planck Inst. /INFN, Rome /Sierra Nevada Observ. /DESY /Padua U. /INFN, Padua /Udine U. /INFN, Udine /Munich, Max Planck Inst. /Munich, Max Planck Inst. /Pisa U. /INFN, Pisa /Barcelona, IFAE /Barcelona, IEEC /Turku U. /Munich, Max Planck Inst. /Lodz U. /Lodz U. /Wurzburg U. /Siena U. /INFN, Siena /Zurich, ETH /Turku U. /INFN, Rome /Sofiya, Inst. Nucl. Res. /Barcelona, IFAE /Munich, Max Planck Inst. /DESY /ICREA, Barcelona /Barcelona, IEEC /Siena U. /INFN, Siena /Sofiya, Inst. Nucl. Res. /Munich, Max Planck Inst. /Munich, Max Planck Inst. /Barcelona, IEEC /Sierra Nevada Observ. /Barcelona, IFAE /Barcelona, Autonoma U.

    2011-12-01

    Suzaku observations of the blazar OJ 287 were performed in 2007 April 10-13 and November 7-9. They correspond to a quiescent and a flaring state, respectively. The X-ray spectra of the source can be well described with single power-law models in both exposures. The derived X-ray photon index and the flux density at 1 keV were found to be {Lambda} = 1.65 {+-} 0.02 and S{sub 1keV} = 215 {+-} 5 nJy, in the quiescent state. In the flaring state, the source exhibited a harder X-ray spectrum ({Lambda} = 1.50 {+-} 0.01) with a nearly doubled X-ray flux density S{sub 1keV} = 404{sub -5}{sup +6} nJy. Moreover, significant hard X-ray signals were detected up to {approx} 27 keV. In cooperation with the Suzaku, simultaneous radio, optical, and very-high-energy {gamma}-ray observations of OJ 287 were performed with the Nobeyama Millimeter Array, the KANATA telescope, and the MAGIC telescope, respectively. The radio and optical fluxes in the flaring state (3.04 {+-} 0.46 Jy and 8.93 {+-} 0.05 mJy at 86.75 Hz and in the V-band, respectively) were found to be higher by a factor of 2-3 than those in the quiescent state (1.73 {+-} 0.26 Jy and 3.03 {+-} 0.01 mJy at 86.75 Hz and in the V-band, respectively). No notable {gamma}-ray events were detected in either observation. The spectral energy distribution of OJ 287 indicated that the X-ray spectrum was dominated by inverse Compton radiation in both observations, while synchrotron radiation exhibited a spectral cutoff around the optical frequency. Furthermore, no significant difference in the synchrotron cutoff frequency was found between the quiescent and flaring states. According to a simple synchrotron self-Compton model, the change of the spectral energy distribution is due to an increase in the energy density of electrons with small changes of both the magnetic field strength and the maximum Lorentz factor of electrons.

  16. Theory and observations: Model simulations of the period 1955-1985

    NASA Technical Reports Server (NTRS)

    Isaksen, Ivar S. A.; Eckman, R.; Lacis, A.; Ko, Malcolm K. W.; Prather, M.; Pyle, J.; Rodhe, H.; Stordal, Frode; Stolarski, R. S.; Turco, R. P.

    1989-01-01

    The main objective of the theoretical studies presented here is to apply models of stratospheric chemistry and transport in order to understand the processes that control stratospheric ozone and that are responsible for the observed variations. The model calculations are intended to simulate the observed behavior of atmospheric ozone over the past three decades (1955-1985), for which there exists a substantial record of both ground-based and, more recently, satellite measurements. Ozone concentrations in the atmosphere vary on different time scales and for several different causes. The models described here were designed to simulate the effect on ozone of changes in the concentration of such trace gases as CFC, CH4, N2O, and CO2. Changes from year to year in ultraviolet radiation associated with the solar cycle are also included in the models. A third source of variability explicitly considered is the sporadic introduction of large amounts of NO sub x into the stratosphere during atmospheric nuclear tests.

  17. Low-altitude quasi-periodic echoes studied using a large database of Gadanki radar observations

    NASA Astrophysics Data System (ADS)

    Venkateswara Rao, N.; Patra, A. K.; Rao, S. V. B.

    2009-01-01

    In this paper we present studies on low-altitude quasiperiodic (LQP) echoes based on a large database of Gadanki radar observations. LQP echoes have been observed 33% of the time during daytime and 39% during nighttime. Their occurrence is found to be maximum in the summer (daytime, 58% nighttime, 57%), followed by the September equinox (daytime, 32% nighttime, 48%), the March equinox (daytime, 26% nighttime, 36%), and minimum in the winter (daytime, 25% nighttime, 26%). Height-time occurrence of LQP echoes shows two local time maxima: one in the morning (0700-1100 LT) and another in the evening (1900-0000 LT). The most significant results not reported earlier are the large occurrence rate of LQP echoes and the height-time occurrence maps showing a descending pattern with close resemblance to tidal wind behavior. The Doppler velocities are upward-northward (downward-southward) for positive- (negative-) sloped LQP echoes. Also, we find the Doppler spread as high as 200 m s-1 at times underlining the presence of strong plasma turbulence in the collision-dominated lower E region. These results are discussed in the light of the current understanding of the LQP echoes.

  18. Plasma-wave observations at Uranus from Voyager 2. Progress report for period ending February 1986

    SciTech Connect

    Gurnett, D.A.; Kurth, W.S.; Scarf, F.L.; Poynter, R.L.

    1986-03-26

    Radio emissions from Uranus were detected by the Voyager 2 plasma-wave instrument about 5 days before closest approach at frequencies of 31.1 and 56.2 khz. The bow shock was identified by an abrupt broadband burst of electrostatic turbulence about 10 hours before closest approach at a radial distance of 23.5 ru. Once inside of the magnetosphere, strong whistler mode hiss and chorus emissions were observed at radial distances less than about 8 R/sub u/, in the same region where the energetic-particle instruments detected intense fluxes of energetic electrons. A variety of other plasma waves, such as (f sub c) electron-cyclotron waves, were also observed in this same region. At the ring plane crossing, the plasma wave instrument detected a large number of impulsive events that are interpreted as impacts of micron-sized dust particles on the spacecraft. The maximum impact rate was about 20 to 30 impacts/sec, and the north-south thickness of the impact region was about 4000 km. This paper presents an overview of the principal results from the plasma-wave instrument, starting with the first detection of radio emissions from Uranus, and ending a few days after closest approach.

  19. Water vapor measurements by Raman lidar during the ARM 1997 water vapor intensive observation period

    SciTech Connect

    Turner, D.D.; Whiteman, D.N.; Schwemmer, G.K.; Evans, K.D. |; Melfi, S.H.; Goldsmith, J.E.

    1998-04-01

    Water vapor is the most important greenhouse gas in the atmosphere, as it is the most active infrared absorber and emitter of radiation, and it also plays an important role in energy transport and cloud formation. Accurate, high resolution measurements of this variable are critical in order to improve the understanding of these processes and thus their ability to model them. Because of the importance of water vapor, the Department of Energy`s Atmospheric Radiation Measurement (ARM) program initiated a series of three intensive operating periods (IOPs) at its Cloud and Radiation Testbed (CART) site in northern Oklahoma. The goal of these IOPs is to improve and validate the state-of-the-art capabilities in measuring water vapor. To date, two of the planned three IOPs have occurred: the first was in September of 1996, with an emphasis on the lowest kilometer, while the second was conducted from September--October 1997 with a focus on both the upper troposphere and lowest kilometer. The ARM CART site is the home of several different water vapor measurement systems. These systems include a Raman lidar, a microwave radiometer, a radiosonde launch site, and an instrumented tower. During these IOPs, additional instrumentation was brought to the site to augment the normal measurements in the attempt to characterize the CART instruments and to address the need to improve water vapor measurement capabilities. Some of the instruments brought to the CART site include a scanning Raman lidar system from NASA/GSFC, additional microwave radiometers from NOAA/ETL, a chilled mirror that was flown on a tethersonde and kite system, and dewpoint hygrometer instruments flow on the North Dakota Citation. This paper will focus on the Raman lidar intercomparisons from the second IOP.

  20. Observation of a periodic runaway in the reactive Ar/O{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect

    Shayestehaminzadeh, Seyedmohammad E-mail: shayesteh@mch.rwth-aachen.de; Arnalds, Unnar B.; Magnusson, Rögnvaldur L.; Olafsson, Sveinn

    2015-11-15

    This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti) with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide) mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O{sub 2} discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate.

  1. Experimental observation of horizontal refractivity gradients during periods of multipath propagation

    NASA Astrophysics Data System (ADS)

    Blanchetiere-Ciarletti, V.; Lavergnat, J.; Sylvain, M.; Weill, A.

    1989-11-01

    The Propagation en Air Clair et Météorologie 3 (PACEM 3) experiment was intended to provide a better understanding of the physical situations and mechanisms that cause multipath propagation on line of sight links. In this experiment we investigated both the horizontal and the vertical gradients of the refractive index. In this paper, after a description of the experiment, we present some results from the aircraft data analysis. During two nights when radio data demonstrated the existence of multipath propagation, the meteorological situations were different, but both involved important horizontal refractivity gradients. The first night showed the combined effect of the wind circulation and relief. We locally found a 15-unit increase in the N value over 10 km. During the second night we observed the arrival and the passage of a moist air mass inducing at the transition a difference of 15-20 N units over about 5 km. A ray-tracing computation taking into account horizontal gradients of refractivity gives evidence of the influence of these horizontal variations upon the area of interfering rays.

  2. VLBI observations of the shortest orbital period black hole binary, MAXI J1659-152

    NASA Astrophysics Data System (ADS)

    Paragi, Z.; van der Horst, A. J.; Belloni, T.; Miller-Jones, J. C. A.; Linford, J.; Taylor, G.; Yang, J.; Garrett, M. A.; Granot, J.; Kouveliotou, C.; Kuulkers, E.; Wijers, R. A. M. J.

    2013-06-01

    The X-ray transient MAXI J1659-152 was discovered by Swift/Burst Alert Telescope and it was initially identified as a gamma-ray burst. Soon its Galactic origin and binary nature were established. There exists a wealth of multiwavelength monitoring data for this source, providing a great coverage of the full X-ray transition in this candidate black hole binary system. We obtained two epochs of European very long baseline interferometry (VLBI) Network (EVN) electronic-VLBI and four epochs of Very Long Baseline Array data of MAXI J1659-152 which show evidence for outflow in the early phases. The overall source properties (polarization, milliarcsecond-scale radio structure, flat radio spectrum) are described well with the presence of a compact jet in the system through the transition from the hard-intermediate to the soft X-ray spectral state. The apparent dependence of source size and the radio core position on the observed flux density (luminosity-dependent core shift) supports this interpretation as well. We see no evidence for major discrete ejecta during the outburst. For the source proper motion we derive 2σ upper limits of 115 μas d-1 in right ascension, and 37 μas d-1 in declination, over a time baseline of 12 d. These correspond to velocities of 1400 and 440 km s-1, respectively, assuming a source distance of ˜7 kpc.

  3. Long-period humidity variability in the Arctic atmosphere from upper-air observations

    NASA Astrophysics Data System (ADS)

    Agurenko, A.; Khokhlova, A.

    2014-12-01

    Under climate change, atmospheric water content also tends to change. This gives rise to changes in the amount of moisture transferred, clouds and precipitation, as well as in hydrological regime. This work analyzes seasonal climatic characteristics of precipitated water in the Arctic atmosphere, by using 1972-2011 data from 55 upper-air stations located north of 60°N. Regions of maximum and minimum mean values and variability trends are determined. In the summer, water amount is shown to increase in nearly the whole of the latitudinal zone. The comparison with the similar characteristics of reanalysis obtained by the other authors shows a good agreement. Time variation in the atmosphere moisture transport crossing 70°N, which is calculated from observation data, is presented and compared with model results. The work is supported by the joint EC ERA.Net RUS and Russian Fundamental Research Fund Project "Arctic Climate Processes Linked Through the Circulation of the Atmosphere" (ACPCA) (project 12-05-91656-ЭРА_а).

  4. Can Any ``Invariants'' Be Revealed in Quasi-periodic Phenomena Observed from Scorpius X-1?

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Sergey; Titarchuk, Lev

    2002-06-01

    Using a large number of Rossi X-Ray Timing Explorer observations of Scorpius X-1, we present a detailed investigation of the transition layer and relativistic precession models (TLM and RPM, respectively). These models predict the existence of the invariant quantities: an inclination angle δ of the magnetospheric axis with the normal to the disk for the TLM and a neutron star (NS) mass MNS for the RPM. Theoretical predictions of both models are tested, and their self-consistency is checked. We establish the following: (1) The inferred δ-value is 5.56d+/-0.09d. Correlation of the δ-values with the horizontal-branch oscillation (HBO) frequency is rather weak. (2) There is a strong correlation between an inferred MNS and the HBO frequency in the RPM frameworks. (3) We infer MNS for different assumptions regarding the relations between the HBO frequency νHBO and the nodal frequency νnod. We find that the inferred MNS=2.7+/-0.1 Msolar cannot be consistent with any equation of state of NS matter. We conclude that the RPM fails to describe the data while the TLM seems to be compatible.

  5. Can Any Invariants Be Revealed in Quasi-periodic Phenomena Observed From Sco X-1?

    NASA Astrophysics Data System (ADS)

    Kuznetsov, S.; Titarchuk, L.

    Using large number of Rossi X-ray Time Explorer observations of Sco X-1 we present a detailed investigation of the transition layer and the relativistic precession models (TLM and RPM, respectively). These models predict the existence of the invariant quantities: an inclination angle delta of the magnetospheric axis with the normal to the disk for the TLM and a neutron star (NS) mass MN S for the RPM. Theoretical predictions of both models are tested and their self-consistency is checked. We establish that: (1) The inferred delta angle is 5.56 +/- 0.09 degrees. Correlation of the delta-values with the horizontal branch oscillation (HBO) frequency is rather weak. (2) There is a strong correlation between an inferred MN S and the HBO frequency in the RPM frameworks. (3) We infer MN S for different assumptions regarding the relations between the HBO frequency and the nodal frequency. We find that the inferred MN S = 2.7 +/- 0.1M cannot be consistent with any EOS of NS matter. We conclude that RPM fails to describe the data while TLM seems to be compatible.

  6. Imaging observation of quasi-periodic disturbances' amplitudes increasing with height in the polar region of the solar corona

    SciTech Connect

    Su, J. T.; Priya, T. G.; Liu, Y.; Shen, Y. D.

    2014-08-01

    At present, there have been few extreme ultraviolet (EUV) imaging observations of spatial variations of the density perturbations due to the slow magnetoacoustic waves (SMWs) propagating along the solar coronal magnetic fields. In this paper, we present such observations taken from the polar region of the corona with the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory and investigate the amplitude of quasi-periodic propagating disturbances that increase with height in the lower corona (0-9 Mm over the solar limb). We statistically determined the following parameters associated with the disturbances: pressure scale height, period, and wavelength in AIA 171 Å, 193 Å, and 211 Å channels. The scale height and wavelength are dependent of temperature, while the period is independent of temperature. The acoustic velocities inferred from the scale height highly correlate with the ratios of wavelength to period, i.e., phase speeds. They provide evidence that the propagating disturbances in the lower corona are likely SMWs and the spatial variations in EUV intensity in the polar region likely reflects the density compressional effect by the propagating SMWs.

  7. VI-Band Follow-Up Observations of Ultra-Long-Period Cepheid Candidates in M31

    NASA Astrophysics Data System (ADS)

    Ngeow, Chow-Choong; Lee, Chien-Hsiu; Ting-Chang Yang, Michael; Lin, Chi-Sheng; Hsiao, Hsiang-Yao; Cheng, Yu-Chi; Lin, Zhong-Yi; Lin, I.-Ling; Kanbur, Shashi M.; Ip, Wing-Huen

    2015-02-01

    The ultra-long-period Cepheids (ULPCs) are classical Cepheids with pulsation periods exceeding ≈ 80 days. The intrinsic brightness of ULPCs are ˜ 1 to ˜ 3 mag brighter than their shorter period counterparts. This makes them attractive in future distance scale work to derive distances beyond the limit set by the shorter period Cepheids. We have initiated a program to search for ULPCs in M31, using the single-band data taken from the Palomar Transient Factory, and identified eight possible candidates. In this work, we presented the VI-band follow-up observations of these eight candidates. Based on our VI-band light curves of these candidates and their locations in the color-magnitude diagram and the Period-Wesenheit diagram, we verify two candidates as being truly ULPCs. The six other candidates are most likely other kinds of long-period variables. With the two confirmed M31 ULPCs, we tested the applicability of ULPCs in distance scale work by deriving the distance modulus of M31. It was found to be {{μ }M31,ULPC}=24.30+/- 0.76 mag. The large error in the derived distance modulus, together with the large intrinsic dispersion of the Period-Wesenheit (PW) relation and the small number of ULPCs in a given host galaxy, means that the question of the suitability of ULPCs as standard candles is still open. Further work is needed to enlarge the sample of calibrating ULPCs and reduce the intrinsic dispersion of the PW relation before re-considering ULPCs as suitable distance indicators.

  8. Quasi-periodic Variations in X-Ray Emission and Long-term Radio Observations: Evidence for a Two-component Jet in Sw J1644+57

    NASA Astrophysics Data System (ADS)

    Wang, Jiu-Zhou; Lei, Wei-Hua; Wang, Ding-Xiong; Zou, Yuan-Chuan; Zhang, Bing; Gao, He; Huang, Chang-Yin

    2014-06-01

    The continued observations of Sw J1644+57 in X-ray and radio bands accumulated a rich data set to study the relativistic jet launched in this tidal disruption event. The X-ray light curve of Sw J1644+57 from 5-30 days presents two kinds of quasi-periodic variations: a 200 s quasi-periodic oscillation (QPO) and a 2.7 day quasi-periodic variation. The latter has been interpreted by a precessing jet launched near the Bardeen-Petterson radius of a warped disk. Here we suggest that the ~200 s QPO could be associated with a second, narrower jet sweeping the observer line-of-sight periodically, which is launched from a spinning black hole in the misaligned direction with respect to the black hole's angular momentum. In addition, we show that this two-component jet model can interpret the radio light curve of the event, especially the re-brightening feature starting ~100 days after the trigger. From the data we infer that inner jet may have a Lorentz factor of Γj ~ 5.5 and a kinetic energy of E k, iso ~ 3.0 × 1052 erg, while the outer jet may have a Lorentz factor of Γj ~ 2.5 and a kinetic energy of E k, iso ~ 3.0 × 1053 erg.

  9. Traveling ionospheric disturbances observed at South African midlatitudes during the 29-31 October 2003 geomagnetically disturbed period

    NASA Astrophysics Data System (ADS)

    Katamzi, Zama T.; Habarulema, John Bosco

    2014-01-01

    This paper presents traveling ionospheric disturbances (TIDs) observations from GPS measurements over the South African region during the geomagnetically disturbed period of 29-31 October 2003. Two receiver arrays, which were along two distinct longitudinal sectors of about 18°-20° and 27°-28° were used in order to investigate the amplitude, periods and virtual propagation characteristics of the storm induced ionospheric disturbances. The study revealed a large sudden TEC increase on 28 October 2003, the day before the first of the two major storms studied here, that was recorded simultaneously by all the receivers used. This pre-storm enhancement was linked to an X-class solar flare, auroral/magnetospheric activities and vertical plasma drift, based on the behaviour of the geomagnetic storm and auroral indices as well as strong equatorial electrojet. Diurnal trends of the TEC and foF2 measurements revealed that the geomagnetic storm caused a negative ionospheric storm; these parameters were depleted between 29 and 31 October 2003. Large scale traveling ionospheric disturbances were observed on the days of the geomagnetic storms (29 and 31 October 2003), using line-of-sight vertical TEC (vTEC) measurements from individual satellites. Amplitude and dominant periods of these structures varied between 0.08-2.16 TECU, and 1.07-2.13 h respectively. The wave structures were observed to propagate towards the equator with velocities between 587.04 and 1635.09 m/s.

  10. Distributed Data Integration Prototype System for Coordinated Enhanced Observing Period (CEOP) Data

    NASA Astrophysics Data System (ADS)

    Miura, S. H.; Aizawa, K.

    2006-12-01

    The purpose of the JAXA Prototype for CEOP Distributed Data Integration Service is to provide user-friendly access to the CEOP (in-situ, satellite and global gridded model output) data. The system is distributed in the sense that, while the system is located in Tokyo, the data is located in archive centers which are globally distributed. The in-situ data is archived at the National Center for Atmospheric Research (NCAR) Earth Observing Laboratory (EOL) in Boulder, Colorado, USA. The NWP global gridded model output data is archived at the Max Planck Institute for Meteorology (MPIM) in cooperation with the World Data Center for Climate (WDC-Climate) in Hamburg, Germany. The satellite data is archived at the IIS (Institute of Industrial Science) at the University of Tokyo, in Tokyo, Japan. Other (non-CEOP) globally distributed data that is on DODS servers can be added in the future according to scientist's requests. The system is integrated in the sense that all of the data is temporally and geospatially coordinated and can be selected and viewed within the same system. The in-situ data are time series data and the global gridded model output data and satellite data are 4D (time series of 2D scenes at levels or in multiple frequency bands). The system knows the geolocation and time of all data sets and supports selection of the data through a uniform set of menus, by data type, reference site and station, and supports sub-setting according to time, area and height/depth. The basic concept for developing the JAXA prototype is " to use existing software where possible". Based on this concept, OPeNDAP, which is widely used in the ocean and atmospheric sciences, was chosen as the data access protocol to enable "access to distributed data". And also the open source Live Access Serve (LAS) was selected as the JAXA Prototype component to enable "integration service". Users can access the system at http://jaxa.ceos.org/wtf_ceop. This system has been online since June 1, 2005

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

    PubMed

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

    2015-03-01

    PM2.5 carbonaceous particles were measured at Gosan, South Korea during 29 March-11 April 2002 which includes a pollution period (30 March-01 April) when the highest concentrations of major anthropogenic species (nss-SO4 (2-), NO3 (-), and NH4 (+)) were observed and a strong Asian dust (AD) period (08-10 April) when the highest concentrations of mainly dust-originated trace elements (Al, Ca, Mg, and Fe) were seen. The concentrations of elemental carbon (EC) measured in the pollution period were higher than those measured in the strong AD period, whereas an inverse variation in the concentrations of organic carbon (OC) was observed. Based on the OC/EC ratios, the possible source that mainly contributed to the highly elevated OC concentrations measured in the strong AD period was biomass burning. The influence of the long-range transport of smoke plumes emitted from regional biomass burning sources was evaluated by using MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data for fire locations and the potential source contribution function analysis. The most potential source regions of biomass burning were the Primorsky and Amur regions in Far Eastern Russia and southeastern and southwestern Siberia, Russia. Further discussion on the source characteristics suggested that the high OC concentrations measured in the strong AD period were significantly affected by the smoldering phase of biomass burning. In addition to biomass burning, secondary OC (SOC) formed during atmospheric long-range transport should be also considered as an important source of OC concentration measured at Gosan. Although this study dealt with the episodic case of the concurrent increase of dust and biomass burning particles, understanding the characteristics of heterogeneous mixing aerosol is essential in assessing the radiative forcing of aerosol. PMID:25253054

  12. Superorbital periodic modulation in wind-accretion high-mass X-ray binaries from swift burst alert telescope observations

    SciTech Connect

    Corbet, Robin H. D.; Krimm, Hans A.

    2013-11-20

    We report the discovery using data from the Swift-Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418–4532, and IGR J16479–4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493–4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393–4643 (= AX J16390.4–4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, Rossi X-Ray Timing Explorer Proportional Counter Array, and International Gamma-Ray Astrophysics Laboratory light curves. 1E 1145.1–6141 may also be worthy of further attention due to the amount of low-frequency modulation of its light curve. However, we find that the presence of superorbital modulation is not a universal feature of wind-accretion supergiant X-ray binaries.

  13. Superorbital Periodic Modulation in Wind-Accretion High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

    NASA Technical Reports Server (NTRS)

    Corbet, Robin H. D.; Krimm, Hans A.

    2013-01-01

    We report the discovery using data from the Swift-Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418-4532, and IGR J16479-4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493-4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393-4643 (= AX J16390.4-4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, Rossi X-Ray Timing Explorer Proportional Counter Array, and International Gamma-Ray Astrophysics Laboratory light curves. 1E 1145.1-6141 may also be worthy of further attention due to the amount of low-frequency modulation of its light curve. However, we find that the presence of superorbital modulation is not a universal feature of wind-accretion supergiant X-ray binaries.

  14. The reconstruction of air pressure in Gdańsk in the period of instrumental observations, 1739-2012

    NASA Astrophysics Data System (ADS)

    Filipiak, Janusz

    2015-04-01

    The purpose of the paper is to characterise the details of reconstruction of air pressure in Gdańsk in the whole period of regular instrumental records spanning the period 1739-2012. Gdańsk pressure series has been reconstructed by joining air pressure observations of 15 local shorter series. The entire instrumental series can be divided into three sub-periods: the Early Observers period, lasting to 1806, the First Meteorological Networks, covering the years from 1807 to 1875 and Modern Measurements begun in 1876. During the first period, observations were made from two to four times per day, sometimes even at midnight. In the 19th century and up to 1945 thrice-daily barometer readings were a standard, in the last few decades the density of data is much denser. A serious gap in the original daily data exists for the period 1849-1875, where it appears that no original source of data have survived. Selected data are presented in the form of five-day or monthly averages. Numerous errors made probably during the re-writing of original observers' data by their assistants were discovered during digitalization. Despite this the quality of observations can be regarded as good. Data have been corrected to provide a monthly-mean measure of atmospheric pressure in the unit of hPa at standard conditions, i.e. standard gravity, 0 °C and at sea level. Some inconsistencies may still arise as the procedure of the homogenization of air temperature is not completed and in case of a few oldest series air temperature was estimated. Numerous breakpoints were identified in the homogenisation of the series and they cannot be always linked to known causes. A reasonably detailed station history has been compiled by incorporating metadata contained in various written sources. These metadata have facilitated the homogenisation of the data series. Mean annual atmospheric pressure in Gdańsk in period 1739-2012 calculated on the basis of homogenized series was 1014.9 hPa. Mean seasonal

  15. Aerosol disturbances of the stratosphere over Tomsk according to data of lidar observations in volcanic activity period 2006-2011

    NASA Astrophysics Data System (ADS)

    Makeev, Andrey P.; Burlakov, Vladimir D.; Dolgii, Sergey I.; Nevzorov, Aleksey V.; Trifonov, Dimitar A.

    2012-11-01

    We summarize and analyze the lidar measurements (Tomsk: 56.5°N; 85.0°E) of the optical characteristics of the stratospheric aerosol layer (SAL) in the volcanic activity period 2006-2011. The background SAL state with minimal aerosol content, which was observed since 1997 under the conditions of long-term volcanically quiescent period, was interrupted in October 2006 by a series of explosive eruptions of volcanoes of the Pacific Ring of Fire: Rabaul (October 2006, New Guinea); Okmok and Kasatochi (July-August 2008, Aleutian Islands); Redoubt (March-April 2009, Alaska); Sarychev Peak (June 2009, Kuril Islands), and Grimsvötn (May 2011, Iceland). A short-term and minor disturbance of the lower stratosphere was also observed in April 2010 after eruption of the Icelandic volcano Eyjafjallajokull. The developed regional empirical model of the vertical distribution of background SAL optical characteristics was used to identify the periods of elevated stratospheric aerosol content after each of the volcanic eruptions.

  16. TESTING THE NO-HAIR THEOREM WITH OBSERVATIONS IN THE ELECTROMAGNETIC SPECTRUM. III. QUASI-PERIODIC VARIABILITY

    SciTech Connect

    Johannsen, Tim; Psaltis, Dimitrios E-mail: dpsaltis@email.arizona.edu

    2011-01-01

    According to the no-hair theorem, astrophysical black holes are uniquely described by their masses and spins. An observational test of the no-hair theorem can be performed by measuring at least three different multipole moments of the spacetime of a black hole and verifying whether their values are consistent with the unique combinations of the Kerr solution. In this paper, we study quasi-periodic variability observed in the emission from black holes across the electromagnetic spectrum as a test of the no-hair theorem. We derive expressions for the Keplerian and epicyclic frequencies in a quasi-Kerr spacetime, in which the quadrupole moment is a free parameter in addition to mass and spin. We show that, for moderate spins, the Keplerian frequency is practically independent of small deviations of the quadrupole moment from the Kerr value, while the epicyclic frequencies exhibit significant variations. We apply this framework to quasi-periodic oscillations (QPOs) in black hole X-ray binaries in two different scenarios. In the case that a pair of QPOs can be identified as the fundamental g- and c-modes in the accretion disk, we show that the no-hair theorem can be tested in conjunction with an independent mass measurement. If pairs of oscillations are identified with non-parametric resonance of dynamical frequencies in the accretion disk, then testing the no-hair theorem also requires an independent measurement of the black hole spin. In addition, we argue that VLBI observations of Sgr A* may test the no-hair theorem through a combination of imaging observations and the detection of quasi-periodic variability.

  17. Observation of a periodic array of flux-closure quadrants in strained ferroelectric PbTiO3 films

    DOE PAGESBeta

    Tang, Y. L.; Zhu, Y. L; Ma, Xiuliang; Borisevich, Albina Y; Morozovska, A. N.; Eliseev, Eugene; Wang, W. Y; Wang, Yujia; Xu, Y. B.; Zhang, Z. D.; et al

    2015-05-01

    Nanoscale ferroelectrics are expected to exhibit various exotic domain configurations, such as the full flux-closure pattern that is well known in ferromagnetic materials. Here we observe not only the atomic morphology of the flux-closure quadrant but also a periodic array of flux closures in ferroelectric PbTiO3 films, mediated by tensile strain on a GdScO3 substrate. Using aberration-corrected scanning transmission electron microscopy, we directly visualize an alternating array of clockwise and counterclockwise flux closures, whose periodicity depends on the PbTiO3 film thickness. In the vicinity of the core, the strain is sufficient to rupture the lattice, with strain gradients up tomore » 109 per meter. We found engineering strain at the nanoscale may facilitate the development of nanoscale ferroelectric devices.« less

  18. Determining factors of observance of antiretroviral treatments in Cameroon during the start-up period (2000-2002)

    PubMed Central

    Commeyras, Christophe; Rey, Jean Loup; Badre-Sentenac, Stéphanie; Essomba-Ntsama, Claudine

    Objective: highlight the socioeconomic and environmental determining factors of long-term observance to antiretroviral treatments in developing countries. Method: The regularity of antiretroviral prescriptions renewal at the central pharmacy of the Yaounde Central Hospital (Cameroon) was measured through analysing the medical and pharmaceutical files of 230 patients over the 21 month start-up period. 99 patients were also interviewed during the last six months. The determining factors were analysed according to various socio-economic criteria, linked with the longitudinal study of treatment observance. Results: The huge price decrease of HIV treatments during the start-up period was conducive to an increase in new treatments by a factor 5.76. In this context of an exploding demand, the paper shows that observance is firstly dependent on quality information about illness and treatment protocols, while longer term adherence is partly dependent on financial capability, and includes the strong influence of living conditions and behaviours. Conclusion: The paper recommends the introduction of free treatment as an objective in national sector policies and the organisation of a long term following-up of patients. In the African context of poverty and actual decentralisation of healthcare, the question of the availability of human resources is profoundly enhanced. PMID:25214897

  19. VI-band follow-up observations of ultra-long-period Cepheid candidates in M31

    SciTech Connect

    Ngeow, Chow-Choong; Yang, Michael Ting-Chang; Lin, Chi-Sheng; Hsiao, Hsiang-Yao; Cheng, Yu-Chi; Lin, Zhong-Yi; Lin, I-Ling; Ip, Wing-Huen; Lee, Chien-Hsiu; Kanbur, Shashi M.

    2015-02-01

    The ultra-long-period Cepheids (ULPCs) are classical Cepheids with pulsation periods exceeding ≈80 days. The intrinsic brightness of ULPCs are ∼1 to ∼3 mag brighter than their shorter period counterparts. This makes them attractive in future distance scale work to derive distances beyond the limit set by the shorter period Cepheids. We have initiated a program to search for ULPCs in M31, using the single-band data taken from the Palomar Transient Factory, and identified eight possible candidates. In this work, we presented the VI-band follow-up observations of these eight candidates. Based on our VI-band light curves of these candidates and their locations in the color–magnitude diagram and the Period–Wesenheit diagram, we verify two candidates as being truly ULPCs. The six other candidates are most likely other kinds of long-period variables. With the two confirmed M31 ULPCs, we tested the applicability of ULPCs in distance scale work by deriving the distance modulus of M31. It was found to be μ{sub M31,ULPC}=24.30±0.76 mag. The large error in the derived distance modulus, together with the large intrinsic dispersion of the Period–Wesenheit (PW) relation and the small number of ULPCs in a given host galaxy, means that the question of the suitability of ULPCs as standard candles is still open. Further work is needed to enlarge the sample of calibrating ULPCs and reduce the intrinsic dispersion of the PW relation before re-considering ULPCs as suitable distance indicators.

  20. The growth of the oceanic boundary layer during the COARE intensive observational period: Large Eddy simulation results

    SciTech Connect

    Skyllingstad, E.D.; Wijesekera, H.W.; Gregg, M.C.

    1995-03-01

    A principal goal of the Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean-Atmosphere Response Experiment (COARE) is to gain an understanding of the processes that control mixing in the upper 100 m of the western tropical Pacific warm pool. The warm pool is an important heat reservoir for the global ocean and is responsible for many of the observed climatic changes associated with El Nino/Southern Oscillation (ENSO) events. This water mass is highly sensitive to mixed-layer processes that are controlled by surface heat, salinity, and momentum fluxes. During most of the year, these fluxes are dominated by solar heating and occasional squalls that freshen the top of the mixed layer and force shallow mixing of about 10-20 m. From November to April, the usual weather pattern is frequently altered by westerly wind bursts that are forced by tropical cyclones and intraseasonal oscillations. These wind bursts generate a strong eastward surface current and can force mixing as deep as 100 m over a period of days. Observations from the intensive observation period (IOP) in COARE indicate that mixed-layer deepening is accompanied by strong turbulence dissipation at the mixed layer base. A short westerly wind burst occurred during the first leg of TOGA-COARE, and lasted about 4-5 days. During this period, the maximum winds were about 10 m s{sup -1}, and the resulting eastward surface flow was about 0.5 m s{sup -1}. The strength of this event was somewhat weaker than a typical westerly wind burst, but the mixed-layer structure and growth are similar to the more vigorous wind bursts discussed.

  1. Period-doubling bifurcation cascade observed in a ferromagnetic nanoparticle under the action of a spin-polarized current

    NASA Astrophysics Data System (ADS)

    Horley, Paul P.; Kushnir, Mykola Ya.; Morales-Meza, Mishel; Sukhov, Alexander; Rusyn, Volodymyr

    2016-04-01

    We report on complex magnetization dynamics in a forced spin valve oscillator subjected to a varying magnetic field and a constant spin-polarized current. The transition from periodic to chaotic magnetic motion was illustrated with bifurcation diagrams and Hausdorff dimension - the methods developed for dissipative self-organizing systems. It was shown that bifurcation cascades can be obtained either by tuning the injected spin-polarized current or by changing the magnitude of applied magnetic field. The order-chaos transition in magnetization dynamics can be also directly observed from the hysteresis curves. The resulting complex oscillations are useful for development of spin-valve devices operating in harmonic and chaotic modes.

  2. Search for a periodic signal from Cygnus X-3 usingmuons observed underground in the Frejus detector (4800 mwe)

    NASA Technical Reports Server (NTRS)

    Bareyre, P.; Barloutaud, R.; Becker, K. H.; Behr, L.; Berger, C.; Bland, R. W.; Chardin, G.; Daum, H. J.; Degrange, B.; Demski, S.

    1986-01-01

    Periodic signals from Cygnus X-3 in the ultra high energy range were recently reported by air shower arrays and attributed to gamma rays. Although gamma rays are expected to produce muon-poor showers, the preceding observations have stimulated similar studies based on underground muons. Two groups have claimed a significant underground signal coming from Cygnus X-3. The results are, however, extremely difficult to explain in the present framework of particle physics, and clearly need confirmation. The preliminary results obtained from the Frejus underground detector during its first 16 months of operation (March 1984 to June 1985) are presented.

  3. Variability of aerosol properties over Eastern Europe observed from ground and satellites in the period from 2003 to 2011

    NASA Astrophysics Data System (ADS)

    Bovchaliuk, A.; Milinevsky, G.; Danylevsky, V.; Goloub, P.; Dubovik, O.; Holdak, A.; Ducos, F.; Sosonkin, M.

    2013-01-01

    The paper presents the study of aerosol variability in the period from 2003 to 2011 over Eastern Europe region with latitude ranging from 40° N to 60° N and longitude from 20° E to 50° E. The analysis was based on the POLDER/PARASOL and POLDER-2/ADEOS satellites and AERONET ground-based sunphotometer observations. The aerosol optical thickness (AOT) of the studied area is characterized by the values (referenced to 870 nm wavelength) ranging from 0.05 to 0.2 except the period of July-August 2010 with strong forest and peat wildfires when the AOT typical values range from 0.3 to 0.5. The analysis of seasonal dynamics of aerosol loading has revealed two AOT high value peaks. The first peak observed in April-May is the result of solitary transportation of Sahara dust in the atmosphere over Eastern Europe, infrequent agricultural fires, transportation of sea salt aerosols by southern winds to Ukraine and Moldova from the Black and Azov Seas. The second peak in August-September is associated with forest and peat wildfires, considerable transportation of Sahara dust and presence of soil dust aerosols due to harvesting activity. The maximum values of AOT are observed in May 2006 (0.1-0.15), April 2009 (0.07-0.15) and August 2010 (0.2-0.5). Furthermore, the study has identified a distinct pattern of anthropogenic aerosols over the industrial areas, especially in the central Ukraine, eastern Belarus, as well as Moscow, Nizhny Novgorod and Stavropol regions in Russia. The comparison of the fine mode AOT (particle radius < 0.3 μm) derived by standard algorithm POLDER/PARASOL from reflected polarized radiances with those recomputed from AERONET inversions was performed over a number of AERONET sites: over Kyiv and Sevastopol sites for the period of 2008-2009 and over Moscow, Minsk, Belsk, and Moldova sites for the period of 2005-2009. The correlation coefficients are 0.78 for Moscow, 0.76 - Minsk, 0.86 - Belsk, 0.93 - Kyiv, 0.81 - Moldova and 0.63 for Sevastopol sites. The

  4. SWIFT OBSERVATIONS OF THE HIGH-MASS X-RAY BINARY IGR J16283-4838 UNVEIL A 288 DAY ORBITAL PERIOD

    SciTech Connect

    Cusumano, G.; Segreto, A.; La Parola, V.; D'Aì, A.; Masetti, N.; Tagliaferri, G.

    2013-09-20

    We report on the temporal and spectral properties of the high-mass X-ray binary IGR J16283-4838 in the hard X-ray band. We searched the first 88 months of Swift Burst Alert Telescope (BAT) survey data for long-term periodic modulations. We also investigated the broad band (0.2-150 keV) spectral properties of IGR J16283-4838 complementing the BAT dataset with soft X-ray data from the available Swift-XRT pointed observations. The BAT light curve of IGR J16283-4838 revealed a periodic modulation at P{sub o} = 287.6 ± 1.7 days (with a significance higher than 4 standard deviations). The profile of the light curve folded at P{sub o} shows a sharp peak lasting ∼12 days over a flat plateau. The long-term light curve also shows a ∼300 day interval of prolonged enhanced emission. The observed phenomenology suggests that IGR J16283-4838 has a Be nature, where the narrow periodic peaks and the ∼300 day outburst can be interpreted as Type I and Type II outbursts, respectively. The broad band 0.2-150 keV spectrum can be described with an absorbed power-law and a steepening in the BAT energy range.

  5. Observations of quasi-periodic scintillations and their possible relation to the dynamics of Es plasma blobs

    SciTech Connect

    Maruyama, Takashi )

    1991-06-01

    Quasi-periodic scintillations at a mid-latitude station, Wakkanai, Japan, are examined using 136-MHz geostationary satellite transmissions. Observations are compared with the ionospheric parameter obtained at the same station and random scintillation records. The results indicate that the quasi-periodic scintillations are most likely produced by plasma blobs within the sporadic E layers. Discussion focuses on characteristics of the ringing pattern which precedes and follows the primary deep fade-out, in field strength. In the majority of events the ringing pattern tends to develop after the distinct deep fade-out, i.e., the pattern is asymmetric. Quasi-periodic scintillation patterns are produced by the movement of plasma blobs in the case of geostationary satellite experiments. Thus the shape of the blob must be deformed so that a steep density gradient is attained on the backside. When the blob is highly deformed by the plasma instability which grows at the steep density gradient, burstlike random scintillations may be produced by the blob. 16 refs.

  6. Spot modelling of periodic weak-line T Tauri stars observed by CoRoT in NGC 2264

    NASA Astrophysics Data System (ADS)

    Lanza, A. F.; Flaccomio, E.; Messina, S.; Micela, G.; Pagano, I.; Leto, G.

    2016-08-01

    Context. The space telescope CoRoT has provided light curves of T Tauri stars belonging to the star-forming region of NGC 2264 with unprecedented continuity and precision in the framework of a coordinated multi-wavelength observational project. Aims: We perform spot modelling of the optical light curves of five weak-line T Tauri stars whose variability is dominated by starspots. Methods: We apply two-spot and evolving single-spot models in the framework of a Bayesian Markov chain Monte Carlo approach to derive the a posteriori distributions of the starspot parameters and the inclination of the star rotation axis. We focus on the rotation periods of the spots that can provide evidence for differential rotation in those stars. Results: We find meaningful results in the case of three stars with an inclination higher than 50° and a slow variation of the light curve amplitude. The relative difference of the spot rotation periods ranges from 0.02 to 0.05 that is 3-10 times larger than the amplitude of the differential rotation found in similar stars with Doppler imaging techniques. Conclusions: We conclude that the intrinsic starspot evolution, although very slow, has a significant impact on the determination of the differential rotation by means of our spot modelling approach. We estimate typical timescales for the evolution of the starspot pattern between ~20 and ~50 rotation periods in our stars.

  7. Medical care costs of patients with rheumatoid arthritis during the prebiologics period in Japan: a large prospective observational cohort study.

    PubMed

    Tanaka, Eiichi; Inoue, Eisuke; Mannalithara, Ajitha; Bennett, Mihoko; Kamitsuji, Shigeo; Taniguchi, Atsuo; Momohara, Shigeki; Hara, Masako; Singh, Gurkirpal; Yamanaka, Hisashi

    2010-02-01

    Our objective was to describe outpatient medical care costs of patients with rheumatoid arthritis (RA) in the prebiologics period in Japan. The outpatient costs of 6,771 RA patients (17,666 patient years) who were enrolled in an observational cohort study at the Institute of Rheumatology, Rheumatoid Arthritis (IORRA), in Tokyo, Japan, were calculated from the billing records dated from 2000 to 2004. Associations between outpatient costs and variables such as age, RA duration, RA disease activities, and disability levels were assessed. The average outpatient cost gradually increased (+7.7% in 4 years) from 271,498 JPY per year in 2000 to 292,417 JPY per year in 2004. Medications accounted for approximately 50% of total outpatient costs, which increased 29.6% during the 4 years. The outpatient costs increased in association with aging, longer RA duration, higher Disease Activity Score of 28 Joints (DAS28), and higher Japanese version of Health Assessment Questionnaire (J-HAQ) score. Generalized linear regression analysis revealed that both DAS28 and J-HAQ scores were the most significant factors associated with outpatient costs (p < 0.001). Outpatient costs for patients with RA increased year after year over the 4-year period under observation in Japan. Medical costs were higher with increasing RA disease activity and disability levels. PMID:19821162

  8. Quasi-periodic Oscillations Associated with Spectral Branches in Rossi X-Ray Timing Explorer Observations of Circinus X-1

    NASA Astrophysics Data System (ADS)

    Shirey, Robert E.; Bradt, Hale V.; Levine, Alan M.; Morgan, Edward H.

    1998-10-01

    We present Rossi X-Ray Timing Explorer (RXTE) All-Sky Monitor observations of the X-ray binary Circinus X-1 that illustrate the variety of intensity profiles associated with the 16.55 day flaring cycle of the source. We also present eight observations of Cir X-1 made with the RXTE Proportional Counter Array over the course of a cycle wherein the average intensity of the flaring state decreased gradually over ~12 days. Fourier power density spectra for these observations show a narrow quasi-periodic oscillation (QPO) peak that shifts in frequency between 6.8 and 32 Hz, as well as a broad QPO peak that remains roughly stationary at ~4 Hz. We identify these as Z-source horizontal and normal branch oscillations (HBOs/NBOs), respectively. Color-color and hardness-intensity diagrams (CDs/HIDs) show curvilinear tracks for each of the observations. The properties of the QPOs and very low frequency noise allow us to identify segments of these tracks with Z-source horizontal, normal, and flaring branches that shift location in the CDs and HIDs over the course of the 16.55 day cycle. These results contradict a previous prediction, based on the hypothesis that Cir X-1 is a high-Ṁ atoll source, that HBOs should never occur in this source.

  9. Quasi-periodic oscillations in accreting magnetic white dwarfs. I. Observational constraints in X-ray and optical

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.; Mouchet, M.; Busschaert, C.; Falize, E.; Michaut, C.

    2015-07-01

    Quasi-periodic oscillations (QPOs) are observed in the optical flux of some polars with typical periods of 1 to 3 s but none have been observed yet in X-rays where a significant part of the accreting energy is released. QPOs are expected and predicted from shock oscillations. Most of the polars have been observed by the XMM-Newton satellite. We made use of the homogeneous set of observations of the polars by XMM-Newton to search for the presence of QPOs in the (0.5-10 keV) energy range and to set significant upper limits for the brightest X-ray polars. We extracted high time-resolution X-ray light curves by taking advantage of the 0.07 s resolution of the EPIC-PN camera. Among the 65 polars observed with XMM-Newton from 1998 to 2012, a sample of 24 sources was selected on the basis of their counting rate in the PN instrument to secure significant limits. We searched for QPOs using Fast Fourier Transform (FFT) methods and defined limits of detection using statistical tools. Among the sample surveyed, none shows QPOs at a significant level. Upper limits to the fractional flux in QPOs range from 7% to 71%. These negative results are compared to the detailed theoretical predictions of numerical simulations based on a 2D hydrodynamical code presented in Paper II. Cooling instabilities in the accretion column are expected to produce shock quasi-oscillations with a maximum amplitude reaching ~40% in the bremsstrahlung (0.5-10 keV) X-ray emission and ~20% in the optical cyclotron emission. The absence of X-ray QPOs imposes an upper limit of ~(5-10) g cm-2 s-1 on the specific accretion rate but this condition is found inconsistent with the value required to account for the amplitudes and frequencies of the observed optical QPOs. This contradiction outlines probable shortcomings with the shock instability model. Figures 1-3 are available in electronic form at http://www.aanda.org

  10. FASTSAT-HSV01 synergistic observations of the magnetospheric response during active periods: MINI-ME, PISA and TTI

    NASA Astrophysics Data System (ADS)

    Casas, Joseph; Collier, Michael; Rowland, Douglas; Sigwarth, John; Boudreaux, Mark

    Understanding the complex processes within the inner magnetosphere of Earth particularly during storm periods requires coordinated observations of the particle and field environment using both in-situ and remote sensing techniques. In fact in order to gain a better understand-ing of our Heliophysics and potentially improve our space weather forecasting capabilities, new observation mission approaches and new instrument technologies which can provide both cost effective and robust regular observations of magnetospheric activity and other space weather related phenomenon are necessary. As part of the effort to demonstrate new instrument tech-niques and achieve necessary coordinated observation missions, NASA's Fast Affordable Sci-ence and Technology Satellite Huntsville 01 mission (FASTSAT-HSV01) scheduled for launch in 2010 will afford a highly synergistic solution which satisfies payload mission opportunities and launch requirements as well as contributing in the near term to our improved understanding of Heliophysics. NASA's FASTSAT-HSV01 spacecraft on the DoD Space Test Program-S26 (STP-S26) Mission is a multi-payload mission executed by the DoD Space Test Program (STP) at the Space Development and Test Wing (SDTW), Kirtland AFB, NM. and is an example of a responsive and economical breakthrough in providing new possibilities for small space technology-driven and research missions. FASTSAT-HSV is a unique spacecraft platform that can carry multiple small instruments or experiments to low-Earth orbit on a wide range of expendable launch vehicles for a fraction of the cost traditionally required for such missions. The FASTSAT-HSV01 mission allows NASA to mature and transition a technical capability to industry while increasing low-cost access to space for small science and technology (ST) payloads. The FASTSAT-HSV01 payload includes three NASA Goddard Space Flight Center (GSFC) new technology built instruments that will study the terrestrial space environment and

  11. A highly efficient tree structure for the biosynthesis of heparan sulfate accounts for the commonly observed disaccharides and suggests a mechanism for domain synthesis.

    PubMed

    Rudd, Timothy R; Yates, Edwin A

    2012-04-01

    The form of the biosynthetic pathway of the biologically and medically important polysaccharides heparan sulfate (HS) and the closely related heparin remain obscure despite significant progress characterising the biosynthetic machinery. Considering possible biosynthetic schemes using a graph approach and applying known constraints of enzyme order and specificity, a previously unreported system with a highly efficient tree structure emerged with two features: (1) All commonly occurring HS disaccharides could be synthesised through a common route, the major branch. (2) The least common disaccharides also occurred on a separate common branch, termed here the minor branch. This suggested that the relative abundance of these two sets of structures were the result of the specificity of a single enzyme (HS epimerase) acting at an early point in the scheme, to convert GlcA-GlcNS to IdoA-GlcNS in preference to converting GlcA-GlcNAc to IdoA-GlcNAc. A third key finding was that the common substrates for 3-O-sulfation all lie on the same (major) branch. The proposed scheme is consistent with a wide body of experiments comprising both biochemical data and results from HS biosynthetic enzyme knockout experiments in the literature. The major branch also contains a bifurcation, providing a choice of two distinct backbone geometries with the same charge. Further development of this novel biosynthetic scheme, in which frame shifts in the site of action of the enzymes were permitted to occur, while maintaining their order of action, suggested a mechanism by which domains could be generated, or further modification blocked. The relationship between the proposed pathway and the geometric and charge possibilities it allows were also explored. PMID:22370609

  12. High Angular Resolution Observations of Episodic Dust Emission from Long Period Variable Stars Twenty Years of Observations with the Berkeley Infrared Spatial Interferometer

    NASA Technical Reports Server (NTRS)

    Danchi, William

    2010-01-01

    Over the past twenty years the U. C. Berkeley Infrared Spatial Interferometer has observed a number of Long Period Variable stars in the mid-infrared, obtaining information on the spatial distribution of dust around these stars with resolutions of the order of a few tens of milliarcseconds. The ISI is a heterodyne interferometer operating mostly at 11.15 microns, initially with two telescopes. In the last decade, it has been taking data regularly with three telescopes, thus obtaining visibility data on three baselines and also a closure phase. Over the course of the years, the ISI has been able to measure the physical properties of the dust shells surrounding these stars, in particular the inner radii of the dust shells, as well as the temperature and density distribution. For some stars, the ISI has also made precision measurements of their diameters in the mid-infrared. Closure phase measurements have revealed asymmetries in the dust distributions around many stars. Most surprisingly the ISI data has shown evidence for substantial changes in the amount of dust on time scales of 5-10 years, rather than being directly correlated with the stellar pulsation periods, which are of the order of one year. We discuss past results and new results from the ISI that highlight the dynamic environment around these stars.

  13. Eclipses in the Middle East from the Late Medieval Islamic Period to the Early Modern Period. Part 1: The observation of six lunar eclipses from the Late Medieval Islamic Period

    NASA Astrophysics Data System (ADS)

    Mozaffari, S. Mohammad

    2013-11-01

    This paper deals with the analysis of data obtained from observations of two sets of three lunar eclipses in the Late Medieval Islamic Period. The first trio consists of the lunar eclipses of 7 March 1262, 7 April 1270 and 24 January 1274, observed by Muḥyī al-Dīn al-Maghribī; from the Maragha Observatory (in north-western Iran), and the second includes those of 2 June and 26 November 1406, and 22 May 1407, observed by Jamshīd Ghiyāth al-Dīn al-Kāshī from Kāshān (in central Iran). The results are that al-Maghribī's values for the magnitudes of these eclipses agree excellently with modern data, and his values for the times when the maximum phases occurred agree to within five minutes with modern values. Al-Kāshī's values for the times of the maximum phases show a rather larger divergence from modern data, varying from about ten minutes to about one hour. The errors in all six values both astronomers computed from their own solar parameters for the longitude of the Sun at the instant of the opposition of the Moon to the Sun in these eclipses remain below ten minutes of arc. The motivation for doing these observations was to measure the lunar epicycle radius r in the Ptolemaic model. Al-Maghribī achieved r = 5;12 and al-Kāshī r ∼ 5;17,1 in terms of the radius of an orbit of R = 60 arbitrary units. It is argued that comparing with modern theory, neither of these two medieval values can be considered an improvement on Ptolemy's value of r = 5;15.

  14. Polar Mesospheric Cloud Occurrence from Geostationary Satellite Observations in the Northern Hemisphere for the Period 2001 to 2005

    NASA Astrophysics Data System (ADS)

    Delaney, C.; Jennings, S. G.; Rodaighe, A.

    2012-04-01

    Polar Mesospheric Clouds (PMC) are the highest clouds in the atmosphere occurring over the summer polar regions at around 83 km in the Mesosphere. Since their discovery in 1885, they have attracted much research and recently they have attracted attention as possible indicators of Climate Change. In the past, their height and optical thinness restricted the opportunities for observation of PMC; however the development of remote sensing satellites has provided a consistent method of observing them in the Mesosphere. Observations of PMC have been made from both numerous polar orbiting satellites and the European geostationary weather satellites (METEOSAT). METEOSAT observations of PMC are in the visible band of the high resolution radiometer (MVIRI) of the first generation weather satellite; they have a greater spatial extent per observation at a higher frequency rate than those of polar orbiting platforms. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) maintains an archive of METEOSAT observations. By building a suitable data management and image analysis infrastructure, we were able to use the archive to make PMC observations in the stored visible band imagery. The design and development of the system (PMC-Explorer) and details of dealing with EUMETSAT data formats are described. PMC occurrence frequencies for the Northern Hemisphere summers are presented for years 2001 to 2005. The seasonal properties are presented, inter-annual comparisons are made and five year seasonal means are calculated and compared with the 1995 season. A comparison with similar published data from polar orbiting satellites is made. An increase PMC in observations between 2001 and 2005 is presented. The potential impact of Climate Change on the occurrence frequency of PMC is discussed. Finally, suggestions are made on further uses of the EUMETSAT archive for PMC research and the potential of comparisons with other remote sensing platforms.

  15. Radio Detection Prospects for a Bulge Population of Millisecond Pulsars as Suggested by Fermi-LAT Observations of the Inner Galaxy

    NASA Astrophysics Data System (ADS)

    Calore, F.; Di Mauro, M.; Donato, F.; Hessels, J. W. T.; Weniger, C.

    2016-08-01

    The dense stellar environment of the Galactic center has been proposed to host a large population of as-yet undetected millisecond pulsars (MSPs). Recently, this hypothesis has found support in an analysis of gamma-rays detected using the Large Area Telescope onboard the Fermi satellite, which revealed an excess of diffuse GeV photons in the inner 15 deg about the Galactic center. The excess can be interpreted as the collective emission of thousands of MSPs in the Galactic bulge, with a spherical distribution strongly peaked toward the Galactic center. In order to fully establish the MSP interpretation, it is essential to find corroborating evidence in multi-wavelength searches, most notably through the detection of radio pulsations from individual bulge MSPs. Based on globular cluster observations and gamma-ray emission from the inner Galaxy, we investigate the prospects for detecting MSPs in the Galactic bulge. While previous pulsar surveys failed to identify this population, we demonstrate that upcoming large-area surveys of this region should lead to the detection of dozens of bulge MSPs. Additionally, we show that deep targeted searches of unassociated Fermi sources should be able to detect the first few MSPs in the bulge. The prospects for these deep searches are enhanced by a tentative gamma-ray/radio correlation that we infer from high-latitude gamma-ray MSPs. Such detections would constitute the first clear discoveries of field MSPs in the Galactic bulge, with far-reaching implications for gamma-ray observations, the formation history of the central Milky Way, and strategy optimization for future deep radio pulsar surveys.

  16. An overview of the lightning and atmospheric electricity observations collected in Southern France during the HYdrological cycle in Mediterranean EXperiment (HyMeX), Special Observation Period 1

    NASA Astrophysics Data System (ADS)

    Defer, E.; Pinty, J.-P.; Coquillat, S.; Martin, J.-M.; Prieur, S.; Soula, S.; Richard, E.; Rison, W.; Krehbiel, P.; Thomas, R.; Rodeheffer, D.; Vergeiner, C.; Malaterre, F.; Pedeboy, S.; Schulz, W.; Farges, T.; Gallin, L.-J.; Ortéga, P.; Ribaud, J.-F.; Anderson, G.; Betz, H.-D.; Meneux, B.; Kotroni, V.; Lagouvardos, K.; Roos, S.; Ducrocq, V.; Roussot, O.; Labatut, L.; Molinié, G.

    2014-08-01

    The PEACH (Projet en Electricité Atmosphérique pour la Campagne HyMeX - the Atmospheric Electricity Project of HyMeX Program) project is the Atmospheric Electricity component of the HyMeX (Hydrology cycle in the Mediterranean Experiment) experiment and is dedicated to the observation of both lightning activity and electrical state of continental and maritime thunderstorms in the area of the Mediterranean Sea. During the HyMeX SOP1 (Special Observation Period; 5 September-6 November 2012), four European Operational Lightning Locating Systems (OLLSs) (ATDNET, EUCLID, LINET, ZEUS) and the HyMeX Lightning Mapping Array network (HyLMA) were used to locate and characterize the lightning activity over the Southeastern Mediterranean at flash, storm and regional scales. Additional research instruments like slow antennas, video cameras, micro-barometer and microphone arrays were also operated. All these observations in conjunction with operational/research ground-based and airborne radars, rain gauges and in situ microphysical records aimed at characterizing and understanding electrically active and highly precipitating events over Southeastern France that often lead to severe flash floods. Simulations performed with Cloud Resolving Models like Meso-NH and WRF are used to interpret the results and to investigate further the links between dynamics, microphysics, electrification and lightning occurrence. A description of the different instruments deployed during the field campaign as well as the available datasets is given first. Examples of concurrent observations from radio frequency to acoustic for regular and atypical lightning flashes are then presented showing a rather comprehensive description of lightning flashes available from the SOP1 records. Then examples of storms recorded during HyMeX SOP1 over Southeastern France are briefly described to highlight the unique and rich dataset collected. Finally the next steps of the work required for the delivery of reliable

  17. Preliminary analysis of the Intensive Observation Period events occurred in Italy during the HyMeX campaign

    NASA Astrophysics Data System (ADS)

    Ferretti, Rossella

    2013-04-01

    HyMeX (Hydrological cycle in the Mediterranean eXperiment) is a project aimed at a better understanding and quantification of the hydrological cycle and related processes in the Mediterranean. As a part of HyMeX, Special Observation Periods (SOPs) are dedicated to provide detailed and specific observations to study key processes leading to orographic precipitation (ORP), heavy precipitation events (HPEs), and flash flood events (FFEs) in certain Target Areas (TAs). Informed by numerical weather forecasts and standard observations, Intensive Operation Periods (IOPs) are declared during the SOPs. Specific observations in the TAs are provided by operational measurements (ground meteorological networks, soundings, and remote-sensing instruments), coupled with specific measurements during IOPs from several instruments, such as disdrometers, sodars, lidars, research radars, extra soundings, etc. In this paper an overview is presented of the HyMeX IOPs in Italy during SOP1 (5 September - 6 November, 2012). The Hydro-Meteorological sites of interest were: Liguria-Tuscany (LT), northeastern Italy (NEI) and central Italy (CI). Typical situations encountered for HPEs in LT involved upper-level southwesterly flow with low-level moist southerly or southeasterly flow over the Tyrrhenian and the Ligurian Sea. Highlights include a measurement of 300 mm/24h of rain at the border between Liguria and Emilia on Sept. 26, 2012 during IOP7b. For NEI region, HPEs mainly occurred with upper level southwesterly flow ahead of advancing troughs with low-level moist southerly or southeasterly flow over the Adriatic Sea. Highlights include 120 mm/24h of rain in Friuli Venezia Giulia on Sept. 12, 2012 during IOP2. For CI region, HPEs and FFEs, a slowly propagating cut-off low centered over southern Italy was observed; the associated easterly flow on the north side of the cut-off low would frequently bring moisture into east central Italy from the Adriatic Sea. Highlights include an event with

  18. Spatial distribution of magnetic fluctuation power with period 40 to 600 s in the magnetosphere observed by THEMIS

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Zhang, Tielong; Ge, Yasong

    2016-04-01

    Ultralow frequency (ULF) fluctuations are ubiquitous in the magnetosphere and have significant influence on the energetic particle transport. We use Time History of Events and Macroscale Interactions During Substorms (THEMIS) data to give the spatial distribution of the Pi2/Pc4- and Pc5-band magnetic fluctuation amplitude near the magnetic equator in the magnetosphere. Statistical results can be summarized as follows: (1) Strong ULF fluctuations are common in the magnetotail plasma sheet; The amplitude of all three components of magnetic fluctuations decreases with decreasing radial distance; (2) During periods of high AE index, fluctuations can propagate toward the Earth as far as the data cutoff in the nightside of the magnetosphere, and the amplitude of magnetic fluctuations is clearly stronger near the dusk sector of the synchronous orbit than that near the dawn sector, suggesting that the substorm particle injection has significant contribution to these fluctuations; (3) Intense compressional Pc5-band magnetic fluctuations are a persistent feature near two flanks of the magnetosphere. Clear peaks of the compressional Pi2/Pc4-band magnetic fluctuation power near two flanks can be found during periods of fast solar wind, while the power of compressional Pi2/Pc4-band fluctuations is weak when the solar wind is slow. (4) Solar wind dynamic pressure and its variations can globally affect the ULF fluctuation power in the magnetosphere. Magnetic fluctuations near the noon side can penetrate from the magnetopause to the synchronous orbit or inner when solar wind pressure variations are large.

  19. Spatial distribution of magnetic fluctuation power with period 40 to 600 s in the magnetosphere observed by THEMIS

    NASA Astrophysics Data System (ADS)

    Wang, G. Q.; Zhang, T. L.; Ge, Y. S.

    2015-11-01

    Ultralow frequency (ULF) fluctuations are ubiquitous in the magnetosphere and have significant influence on the energetic particle transport. We use Time History of Events and Macroscale Interactions during Substorms (THEMIS) data to give the spatial distribution of the Pi2/Pc4 and Pc5 band magnetic fluctuation amplitude near the magnetic equator in the magnetosphere. Statistical results can be summarized as follows: (1) strong ULF fluctuations are common in the magnetotail plasma sheet; the amplitude of all three components of magnetic fluctuations decreases with decreasing radial distance; (2) during periods of high AE index, fluctuations can propagate toward the Earth as far as the data cutoff in the nightside of the magnetosphere, and the amplitude of magnetic fluctuations is clearly stronger near the dusk sector of the synchronous orbit than that near the dawn sector, suggesting that the substorm particle injection has significant contribution to these fluctuations; (3) intense compressional Pc5 band magnetic fluctuations are a persistent feature near two flanks of the magnetosphere. Clear peaks of the compressional Pi2/Pc4 band magnetic fluctuation power near two flanks can be found during periods of fast solar wind, while the power of compressional Pi2/Pc4 band fluctuations is weak when the solar wind is slow. (4) Solar wind dynamic pressure and its variations can globally affect the ULF fluctuation power in the magnetosphere. Magnetic fluctuations near the noonside can penetrate from the magnetopause to the synchronous orbit or inner when solar wind pressure variations are large.

  20. B-Field Determination from Magnetoacoustic Oscillations in Kilohertz Quasi-periodic Oscillation Neutron Star Binaries: Theory and Observations

    NASA Astrophysics Data System (ADS)

    Titarchuk, L. G.; Bradshaw, C. F.; Wood, K. S.

    2001-10-01

    We present a method for determining the B-field around neutron stars based on observed kilohertz and viscous quasi-periodic oscillation (QPO) frequencies used in combination with the best-fit optical depth and temperature of a Comptonization model. In the framework of the transition layer QPO model, we analyze the magnetoacoustic wave (MAW) formation in the layer between a neutron star surface and the inner edge of a Keplerian disk. We derive formulas for the MAW frequencies for different regimes of radial transition layer oscillations. We demonstrate that our model can use the QPO as a new kind of probe to determine the magnetic field strengths for 4U 1728-42, GX 340+0, and Scorpius X-1 in the zone where the QPOs occur. Observations indicate that the dependence of the viscous frequency on the Keplerian frequency is closely related to the inferred dependence of the MAW frequency on the Keplerian frequency for a dipole magnetic field. The MAW dependence is based on a single parameter, the magnetic moment of the star as estimated from the field strength in the transition layer. The best-fit magnetic moment parameter is about (0.5-1)×1025 G cm3 for all studied sources. From observational data, the magnetic fields within distances less than 20 km from the neutron star for all three sources are strongly constrained to be dipole fields with the strengths of 107-108 G on the neutron star surface.

  1. Observations of the Nocturnal Boundary Layer and Morning Transitional Periods in Houston, Texas during the TexAQS II Campaign

    NASA Astrophysics Data System (ADS)

    Day, B. M.; Clements, C. B.; Rappenglueck, B.

    2007-12-01

    High-temporal resolution tethersonde profiles taken during the TexAQS II field campaign in Houston were used to study the overnight development and progression of the nocturnal boundary layer (NBL) and the evolution of the convective boundary layer after sunrise. The measurements were made at the University of Houston campus, located approximately 4 km southeast of the downtown Houston central business district, and consisted of vertical profiles of potential temperature, water vapor mixing ratio, wind speed, wind direction, and ozone concentration. Profile heights averaged 250 m AGL with a few reaching 400 m AGL. Profiles were taken at approximately 30 min intervals throughout 4 nights during Intensive Observational Periods (IOPs), including both the evening and morning transitional periods. Tethersonde experiments also were performed during several additional morning break-up periods during the campaign. Preliminary results from the overnight experiments of Sept 7-8 and Sept 14-15, 2006 showed different NBL evolutions. Sept 7-8 exhibited a stronger and deeper inversion compared with Sept 14-15 when the inversion was weak with a fairly constant height throughout the night. The Sept 7-8 profiles showed elevated bluff-like structures in the virtual potential temperature profiles between 0300-0400 CDT, indicating neutral stability within the 40-90 m AGL level. And, just before sunrise a neutral layer with constant potential temperature developed between the surface and 75 m AGL reflecting horizontal cold air advection. Further analyses will be presented for other vertical profiles taken during the campaign, including the additional overnight profiles as well as the profiles taken during the morning transition to the convective boundary layer.

  2. Variability of aerosol properties over Eastern Europe observed from ground and satellites in the period from 2003 to 2011

    NASA Astrophysics Data System (ADS)

    Bovchaliuk, A.; Milinevsky, G.; Danylevsky, V.; Goloub, P.; Dubovik, O.; Holdak, A.; Ducos, F.; Sosonkin, M.

    2013-07-01

    The paper presents some results of the study on aerosol variability in the period from 2003 to 2011 over the Eastern Europe region, with latitude ranging from 40° N to 60° N and longitude from 20° E to 50° E. The analysis was based on the POLDER/PARASOL and POLDER-2/ADEOS satellites and AERONET (AErosol RObotic NETwork) ground-based sun photometer observations. The aerosol optical thickness (AOT) of the studied area is characterized by values (referenced to 870 nm wavelength) ranging from 0.05 to 0.2, except for in the period of July-August 2010 with strong forest and peat wildfires when the AOT typical values range from 0.3 to 0.5 according to both retrievals. The analysis of seasonal dynamics of aerosol loading has revealed two AOT high value peaks. The spring peak observed in April-May is the result of solitary transportation of Saharan dust in the atmosphere over Eastern Europe, infrequent agricultural fires, transportation of sea salt aerosols by southern winds to Ukraine and Moldova from the Black and Azov seas. The autumn peak in August-September is associated with forest and peat wildfires, considerable transportation of Saharan dust and the presence of soil dust aerosols due to harvesting activity. The maximum values of AOT are observed in May 2006 (0.1-0.15), April 2009 (0.07-0.15) and August 2010 (0.2-0.5). Furthermore, the study has identified a distinct pattern of anthropogenic aerosols over the industrial areas, especially in central Ukraine and eastern Belarus as well as Moscow region in Russia. The comparison of the AOT derived by standard algorithm POLDER/PARASOL with those recomputed from AERONET inversions for fine mode particles with radius < 0.3 μm was performed over several AERONET sites. The correlation coefficients for the POLDER/AERONET AOT retrieval comparisons are equal: 0.78 for Moscow site, 0.76 - Minsk, 0.86 - Belsk, 0.81 - Moldova (period 2005-2009), 0.93 - Kyiv and 0.63 for Sevastopol sites (2008-2009). The deviations are

  3. Luminosity and spin-period evolution of GX 304-1 during outbursts from 2009 to 2013 observed with the MAXI/GSC, RXTE/PCA, and Fermi/GBM

    NASA Astrophysics Data System (ADS)

    Sugizaki, Mutsumi; Yamamoto, Takayuki; Mihara, Tatehiro; Nakajima, Motoki; Makishima, Kazuo

    2015-08-01

    A report is made on the luminosity and pulse period evolution of the Be binary X-ray pulsar GX 304-1 during a series of outbursts from 2009 to 2013 observed by MAXI/GSC, RXTE/PCA, and Fermi/GBM. In total, 12 outbursts repeated by ˜ 132.2 d were observed, which is consistent with the X-ray periodicity of this object observed in the 1970s. These 12 outbursts, together with those in the 1970s, were all found to recur with a well-defined period of 132.189 ± 0.02 d, which can be identified with the orbital period. The pulse period of ˜ 275 s, obtained from the RXTE/PCA and Fermi/GBM data, apparently exhibited a periodic modulation synchronized with the outburst period, suggesting the pulsar orbital motion, which is superposed on a secular spin-up trend throughout the entire active phase. The observed pulse period changes were successfully represented by a model composed of the binary orbital modulation and pulsar spin up caused by mass accretion through an accretion disk. The orbital elements obtained from the best-fit model, including the projected orbital semi-major axis ax sin i ≃ 500-600 light-s and an eccentricity e ≃ 0.5, are typical of Be binary X-ray pulsars.

  4. Vertical structure of the wind field during the Special Observing Period I of the Global Weather Experiment

    NASA Technical Reports Server (NTRS)

    Paegle, J. N.; Paegle, J.; Zhen, Z.; Sampson, G.

    1986-01-01

    The vertical structure of the global atmosphere is analyzed for selected periods of the Special Observing Period I (SOP-I) for the Global Weather Experiment (GWE). The analysis consists of projection of the stream-function and velocity potential at 200 and 850 mb on spherical harmonics and of the wind and height fields on the normal modes of a linearized form of the primitive equations for a basic state at rest. The kinematic vertical structure is discussed in terms of correlation coefficients of the 200 mb and 850 mb winds and analysis of the internal and external normal modes of the primitive equations. The reliability of the results is checked by applying the same analysis methods to data sets obtained from three different institutions: Geophysical Fluid Dynamics Laboratory (GFDL), European Center for Medium Range Weather Forecasting (ECMWF), and Goddard Laboratory for the Atmospheres (GLA). It is found that, on a global basis, vertically reversing circulations are as important as the equivalent barotropic structures. For the verticaly reversing components, the gravity and mixed Rossby-gravity modes have contributions of the same order of magnitude as those of the Rossby modes in tropical latitudes.

  5. Ovariectomy-associated changes in interradicular septum and in tibia metaphysis in different observation periods in rats.

    PubMed

    Esteves, Carina M; Moraes, Renata M; Gomes, Francine C; Marcondes, Meryenn S; Lima, Gabriela M G; Anbinder, Ana Lia

    2015-02-01

    In order to standardize an experimental model to study the effects of absence of ovarian hormones in maxillary bones compared with long bones, the aim of this research was to analyze the influence of ovariectomy (OVX) on rat alveolar bone and tibiae, in different observation periods. Thirty-six female rats were ovariectomized or sham operated. After 60, 90 or 120 days, the animals were sacrificed and their hemimandibles, maxillae and tibiae were removed and routinely prepared for hematoxylin and eosin staining. The percentage of bone matrix area in bone septum in the first molar furcation region, and in tibial metaphysis was calculated, and data were submitted to statistical analysis (p<0.05). As regards the histomorphometrical analysis in jaw bones, there was no statistical difference between groups, while the effects of ovariectomy on tibiae were seen as early as 60 days. According to the methods used, there was no significant influence of absence of ovarian hormones on interradicular septum of mandibular or maxillary first molars in the periods studied, despite the reduction in bone matrix area in tibia metaphysis as early as 60 days. PMID:25532670

  6. An overview of the lightning and atmospheric electricity observations collected in southern France during the HYdrological cycle in Mediterranean EXperiment (HyMeX), Special Observation Period 1

    NASA Astrophysics Data System (ADS)

    Defer, E.; Pinty, J.-P.; Coquillat, S.; Martin, J.-M.; Prieur, S.; Soula, S.; Richard, E.; Rison, W.; Krehbiel, P.; Thomas, R.; Rodeheffer, D.; Vergeiner, C.; Malaterre, F.; Pedeboy, S.; Schulz, W.; Farges, T.; Gallin, L.-J.; Ortéga, P.; Ribaud, J.-F.; Anderson, G.; Betz, H.-D.; Meneux, B.; Kotroni, V.; Lagouvardos, K.; Roos, S.; Ducrocq, V.; Roussot, O.; Labatut, L.; Molinié, G.

    2015-02-01

    The PEACH project (Projet en Electricité Atmosphérique pour la Campagne HyMeX - the Atmospheric Electricity Project of the HyMeX Program) is the atmospheric electricity component of the Hydrology cycle in the Mediterranean Experiment (HyMeX) experiment and is dedicated to the observation of both lightning activity and electrical state of continental and maritime thunderstorms in the area of the Mediterranean Sea. During the HyMeX SOP1 (Special Observation Period) from 5 September to 6 November 2012, four European operational lightning locating systems (ATDnet, EUCLID, LINET, ZEUS) and the HyMeX lightning mapping array network (HyLMA) were used to locate and characterize the lightning activity over the northwestern Mediterranean at flash, storm and regional scales. Additional research instruments like slow antennas, video cameras, microbarometer and microphone arrays were also operated. All these observations in conjunction with operational/research ground-based and airborne radars, rain gauges and in situ microphysical records are aimed at characterizing and understanding electrically active and highly precipitating events over southeastern France that often lead to severe flash floods. Simulations performed with cloud resolving models like Meso-NH and Weather Research and Forecasting are used to interpret the results and to investigate further the links between dynamics, microphysics, electrification and lightning occurrence. Herein we present an overview of the PEACH project and its different instruments. Examples are discussed to illustrate the comprehensive and unique lightning data set, from radio frequency to acoustics, collected during the SOP1 for lightning phenomenology understanding, instrumentation validation, storm characterization and modeling.

  7. Observations of Sub-3 nm Particles and Sulfuric acid Concentrations during Aerosol Life Cycle Intensive Observation Period 2011 in Long Island, New York

    NASA Astrophysics Data System (ADS)

    Yu, H.; Kanawade, V. P.; You, Y.; Hallar, A. G.; Mccubbin, I. B.; Chirokova, G.; Sedlacek, A. J.; Springston, S. R.; Wang, J.; Kuang, C.; Lee, Y.; McGraw, R. L.; Mikkila, J.; Lee, S.

    2012-12-01

    Atmospheric new particle formation (NPF) is an important source of aerosol particles. But the NPF processes are not well understood, in part because of our limited understanding of the formation of atmospheric sub-3 nm size aerosols and the limited number of simultaneous observations of particle size distributions and the aerosol nucleation precursors. During Aerosol Life Cycle Intensive Observation Period (July-August 2011) in Long Island, New York, we deployed a particle size magnifier (Airmodus A09) running at different working fluid saturation ratios and a TSI CPC3776 to extract the information of sub-3 nm particles formation. A scanning mobility particle spectrometer (SMPS), a chemical ionization mass spectrometer (CIMS), and a number of atmospheric trace gas analyzers were used to simultaneously measure aerosol size distributions, sulfuric acid, and other possible aerosol precursors, respectively. Our observation results show that sub-3 nm particles existed during both NPF and non-NPF events, indicating the formation of sub-3nm particle didn't always lead to NPF characterized by typical banana shaped aerosol size distributions measured by SMPS. However, sub-3 nm particles were much higher during NPF events. Sub-3 nm particles were well-correlated with sulfuric acid showing the same diurnal variations and noontime peaks, especially for NPF days. These results are consistent with laboratory studies showing that formation of sub-3 nm particles is very sensitive to sulfuric acid (than amines and ammonia) [Yu et al. GRL 2012]. HYSPLIT back trajectory analysis indicates that air masses from Great Lakes, containing more SO2, VOCs and secondary organics, may contribute to growth of sub-3 nm particles and NPF.

  8. Long-period (12sec) Volcanic Tremor Observed at Usu 2000 Eruption: Seismological Detection of a Deep Magma Plumbing system

    NASA Astrophysics Data System (ADS)

    KAWAKATSU, H.; YAMAMOTO, M.

    2001-12-01

    Mt. Usu is a dacitic stratovolcano located in southwestern Hokkaido, Japan, and has erupted repeatedly (in 1910, 1943-45, and 1977-78). In the end of March 2000, after twenty some years of quiescence, Usu volcano began its activity with an intensive earthquake swarm. After several days of the earthquake swarm, on March 31, 2000, the eruption began at the northwest foot of the volcano. We have installed five broadband seismometers around the volcano, and detected long period (12 sec) tremors (hereafter called LPTs) which are continually emitted from the volcano. Although these LPTs are continually observed at an interval of a few minutes, there exist no corresponding surface activities such as eruptions. The source of these LPTs are located relatively deep at a depth of 5 km, and their amplitude variation well correlates with the uplift rate of the eruption area. We thus attribute these LPTs to the flow induced vibration of a magma chamber and its outlet located around the source region of the LPTs. The estimated moment tensor for LPTs shows a reversed polarity for the isotropic and CLVD components. This is consistent with a combination of a deflating spherical source and an inflating crack which opens northwestern direction toward the eruption site. The volumetric magma flow rate may be estimated from the observed RMS amplitude of LPT through a seismic moment rate, and turns out to be around 3*E5 m3 per day. Geodetic observations report the volume change of the order of 107 m3 within the first few days. It appears that the volume flow rate estimated from LPTs is about one order of magnitude smaller than that of the actual flow rate. This may be reasonable if we consider that through seismic waves we are observing a fluctuating part of the magma flow. This may be the first seismological detection of dynamics of a main magma plumbing system beneath volcanos directly related to eruption activities.

  9. Observations of Non-Methane Hydrocarbons Over India During the Asian Summer Monsoon Period: Results from CARIBIC

    NASA Astrophysics Data System (ADS)

    Baker, A. K.; Schuck, T. J.; Slemr, F.; Brenninkmeijer, C. A.

    2008-12-01

    The CARIBIC project (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container, www.caribic-atmospheric.com) involves the monthly deployment of an instrument container equipped to make atmospheric measurements from onboard a long-range commercial airliner. Since December 2004, flights for the second phase of CARIBIC have been aboard a Lufthansa Airbus A340-600 traveling between Frankfurt, Germany and destinations in Asia, North America and South America. The instrument package housed in the container (1.5 ton) is fully automated and during each monthly set of flights carries out a variety of real-time trace gas and aerosol measurements, and also collects 28 air samples, which are analyzed upon return to the laboratory. Routine measurements made from the sampling flasks include non-methane hydrocarbon (NMHC) analysis, and these measurements provide the basis for the data presented here. Between April and September of 2008, the container was deployed monthly on two sequential roundtrip flights between Frankfurt and Chennai, India. To achieve greater resolution, air samples were collected only on the first of the roundtrip flights, with 14 samples collected on the flight to Chennai and 14 collected on the return. These flights provided the opportunity to study the composition of the upper troposphere in this region during the Asian summer monsoon period (typically June-September), which is characterized by anticyclonic circulation in the upper troposphere coupled with deep convection. Samples collected during the monsoon period exhibit elevated levels of NMHCs relative to samples collected outside of the monsoon period, with enhancements in ethyne and benzene being more substantial than enhancements in the alkanes. Enhanced mixing ratios are observed between 15N and 40N, and correspond to enhancements in other trace gases, namely methane and CO. Ethyne in particular is strongly correlated with both methane and CO in this region

  10. Water quality observations of ice-covered, stagnant, eutrophic water bodies and analysis of influence of ice-covered period on water quality

    NASA Astrophysics Data System (ADS)

    sugihara, K.; Nakatsugawa, M.

    2013-12-01

    incorporates the freezing-over of water bodies. The constructed model shows good temporal and spatial reproducibility and enables water quality to be forecast throughout the year, including during the ice-covered period. The forecasts using the model agree well with the survey results of shortened ice period and climate-change-related increase in the BOD in spring. From the result of calculations and observations, it is suggested that water quality of spring has been deteriorate because of freezing period to be shortened due to temperature rising.

  11. Some observations regarding the thermal flux from Earth's erupting volcanoes for the period of 2000 to 2014

    NASA Astrophysics Data System (ADS)

    Wright, Robert; Blackett, Matthew; Hill-Butler, Charley

    2015-01-01

    present satellite measurements of the thermal flux observed from 95 active volcanoes, based on observations made daily over the past 15 years by NASA's Terra and Aqua Moderate Resolution Imaging Spectroradiometer sensors. Excursions from an apparent baseline level of thermal emission are attributable to episodic lava-flow-forming eruptions. Highest average intensity was associated with the July 2001 eruption of Etna, Italy, which radiated an average of 2.5 × 109 W over 23 days. However, recent fissure eruptions in the Afar Rift have attained higher average intensities of 2.4-4.4 × 109 W, albeit for days, not weeks. The largest magnitude eruption was the ongoing eruption of Bardarbunga, Iceland, which radiated 2.6 × 1016 J. Kīlauea, Hawai'i, has radiated the most energy since 2000, although the lava lake at Nyiragongo, Democratic Republic of Congo, comes a close second. Time series analysis reveals evidence for periodicity in radiant flux at some volcanoes but not at others.

  12. Direct observation of single stationary-phase bacteria reveals a surprisingly long period of constant protein production activity

    PubMed Central

    Gefen, Orit; Fridman, Ofer; Ronin, Irine; Balaban, Nathalie Q.

    2014-01-01

    Exponentially growing bacteria are rarely found in the wild, as microorganisms tend to spend most of their lifetime at stationary phase. Despite this general prevalence of stationary-phase bacteria, they are as yet poorly characterized. Our goal was to quantitatively study this phase by direct observation of single bacteria as they enter into stationary phase and by monitoring their activity over several days during growth arrest. For this purpose, we devised an experimental procedure for starving single Escherichia coli bacteria in microfluidic devices and measured their activity by monitoring the production rate of fluorescent proteins. When amino acids were the sole carbon source, the production rate decreased by an order of magnitude upon entry into stationary phase. We found that, even while growth-arrested, bacteria continued to produce proteins at a surprisingly constant rate over several days. Our identification of this newly observed period of constant activity in nongrowing cells, designated as constant activity stationary phase, makes possible the conduction of assays that require constant protein expression over time, and are therefore difficult to perform under exponential growth conditions. Moreover, we show that exogenous protein expression bears no fitness cost on the regrowth of the population when starvation ends. Further characterization of constant activity stationary phase—a phase where nongrowing bacteria can be quantitatively studied over several days in a reproducible manner—should contribute to a better understanding of this ubiquitous but overlooked physiological state of bacteria in nature. PMID:24344288

  13. Subjective and objective observation of skin graft recovery on Indonesian local cat with different periods of transplantation time

    PubMed Central

    Erwin; Gunanti; Handharyani, Ekowati; Noviana, Deni

    2016-01-01

    Aim: The success of a skin graft in a cat is highly dependent on the granulation formed by the base of recipient bed. Granulation by the base of recipient bed will form after several days after injury. This research aimed to observe subjective and objective profile of skin graft recovery on forelimb of cats with different periods of donor skin placement. Materials and Methods: Nine male Indonesian local cats aged 1-2 years old, weighing 3-4 kg were divided into three groups. The first surgery for creating defect wound of 2 cm×2 cm in size was performed in the whole group. The wound was left for several days with the respective interval for each group, respectively: Group I (for 2 days), Group II (for 4 days), and Group III (for 6 days). In the whole group, the second surgery was done by the harvesting skin of thoracic area which then applied on recipient bed of respective groups. Result: The donor skin on Group II was accepted faster compared to Group I and Group III. The donor skin did not show color differences compared to surrounding skin, painless, bright red in bleeding test had faster both hair growth and drug absorption. Test toward the size of donor skin and the effect of drugs did not show a significant difference between each group. Conclusion: The observe subjective and objective profile of skin graft recovery on forelimb of cats on Group II were accepted faster compared to Group I and III. PMID:27284224

  14. AROME-WMED, a real-time mesoscale model designed for the HyMeX special observation periods

    NASA Astrophysics Data System (ADS)

    Fourrié, N.; Bresson, É.; Nuret, M.; Jany, C.; Brousseau, P.; Doerenbecher, A.; Kreitz, M.; Nuissier, O.; Sevault, E.; Bénichou, H.; Amodei, M.; Pouponneau, F.

    2015-07-01

    During autumn 2012 and winter 2013, two special observation periods (SOPs) of the HYdrological cycle in the Mediterranean EXperiment (HyMeX) took place. For the preparatory studies and to support the instrument deployment during the field campaign, a dedicated version of the operational convective-scale Application of Research to Operations at Mesoscale (AROME)-France model was developed: the AROME-WMED (West Mediterranean Sea) model. It covers the western Mediterranean basin with a 48 h forecast range. It provided real-time analyses and forecasts which were sent daily to the HyMeX operational centre to forecast high-precipitation events and to help decision makers on the deployment of meteorological instruments. This paper presents the main features of this numerical weather prediction system in terms of data assimilation and forecast. Some specific data of the HyMeX SOP were assimilated in real time. The forecast skill of AROME-WMED is then assessed with objective scores and compared to the operational AROME-France model, for both autumn 2012 (05 September to 06 November 2012) and winter 2013 (01 February to 15 March 2013) SOPs. The overall performance of AROME-WMED is good for the first HyMeX special observation period (SOP1) (i.e. mean 2 m temperature root mean square error (RMSE) of 1.7 °C and mean 2 m relative humidity RMSE of 10 % for the 0-30 h forecast ranges) and similar to those of AROME-France for the 0-30 h common forecast range (maximal absolute difference of 2 m temperature RMSE of 0.2 °C and 0.21 % for the 2 m relative humidity); conversely, for the 24-48 h forecast range it is less accurate (relative loss between 10 and 12 % in 2 m temperature and relative humidity RMSE, and equitable threat score (ETS) for 24 h accumulated rainfall), but it remains useful for scheduling observation deployment. The characteristics of parameters, such as precipitation, temperature or humidity, are illustrated by one heavy precipitation case study that occurred

  15. TIME DELAYS IN QUASI-PERIODIC PULSATIONS OBSERVED DURING THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15

    SciTech Connect

    Dolla, L.; Marque, C.; Seaton, D. B.; Dominique, M.; Berghmans, D.; Cabanas, C.; De Groof, A.; Verdini, A.; West, M. J.; Zhukov, A. N.; Van Doorsselaere, T.; Schmutz, W.; Zender, J.

    2012-04-10

    We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on timescale 1-30 s and find different time lags between different wavebands. During the impulsive phase, the Reuven Ramaty High Energy Solar Spectroscopic Imager channels in the range 25-100 keV lead all the other channels. They are followed by the Nobeyama RadioPolarimeters at 9 and 17 GHz and the extreme-ultraviolet (EUV) channels of the Euv SpectroPhotometer (ESP) on board the Solar Dynamic Observatory. The zirconium and aluminum filter channels of the Large Yield Radiometer on board the Project for On-Board Autonomy satellite and the soft X-ray (SXR) channel of ESP follow. The largest lags occur in observations from the Geostationary Operational Environmental Satellite, where the channel at 1-8 A leads the 0.5-4 A channel by several seconds. The time lags between the first and last channels is up to Almost-Equal-To 9 s. We identified at least two distinct time intervals during the flare impulsive phase, during which the QPPs were associated with two different sources in the Nobeyama RadioHeliograph at 17 GHz. The radio as well as the hard X-ray channels showed different lags during these two intervals. To our knowledge, this is the first time that time lags are reported between EUV and SXR fluctuations on these timescales. We discuss possible emission mechanisms and interpretations, including flare electron trapping.

  16. Estimation of scan-gap limits on phase delay connections in Delta VLBI observations based on the phase structure function at a short time period

    NASA Astrophysics Data System (ADS)

    Kondo, T.; Hobiger, T.; Sekido, M.; Ichikawa, R.; Koyama, Y.; Takaba, H.

    2009-03-01

    The maximum scan-gap length which connects phase delays from scan to scan over a gap is an important issue in Delta Very Long Baseline Interferometry (D-VLBI), and it is affected by delay fluctuations caused by the wet troposphere. It has recently become possible to obtain near real-time fringe phases by using an e-VLBI technique that realizes real-time VLBI by connecting stations through high-speed Internet. Such real-time VLBI raises the possibility of dynamic D-VLBI scheduling, which changes scan and gap length dynamically according to the weather condition of the date. We have investigated this possibility by using phase structure functions obtained from continuous VLBI observations at S- and X-bands for 1-2 h at the Kashima, Gifu, and Koganei stations (not real-time ones). Five VLBI sessions were conducted during this study between March and July 2006 under different weather conditions. At first a simple method was developed to evaluate phase connectivity from a phase structure function. A model was also proposed to estimate a phase-structure function at longer time periods from a short time period. Finally, an available gap length was estimated using the model. Our results show that it is possible to estimate an available scan gap length by using a structure function at a time period of 10 s. This suggests that it is possible to control scan length and gap length dynamically in order to achieve the best performance of D-VLBI observations.

  17. The quasi-biennial periodicity (QBP) in velocity and intensity helioseismic observations. The seismic QBP over solar cycle 23

    NASA Astrophysics Data System (ADS)

    Simoniello, R.; Finsterle, W.; Salabert, D.; García, R. A.; Turck-Chièze, S.; Jiménez, A.; Roth, M.

    2012-03-01

    Aims: We looked for signatures of quasi-biennial periodicity (QBP) over different phases of solar cycle by means of acoustic modes of oscillation. Low-degree p-mode frequencies are shown to be sensitive to changes in magnetic activity due to the global dynamo. Recently there has been reported evidence of two-year variations in p-mode frequencies. Methods: Long high-quality helioseismic data are provided by BiSON (Birmingham Solar Oscillation Network), GONG (Global Oscillation Network Group), GOLF (Global Oscillation at Low Frequency) and VIRGO (Variability of Solar IRradiance and Gravity Oscillation) instruments. We determined the solar cycle changes in p-mode frequencies for spherical degree ℓ = 0, 1, 2 with their azimuthal components in the frequency range 2.5 mHz ≤ ν ≤ 3.5 mHz. Results: We found signatures of QBP at all levels of solar activity in the modes more sensitive to higher latitudes. The signal strength increases with latitude and the equatorial component also seems to be modulated by the 11-year envelope. Conclusions: The persistent nature of the seismic QBP is not observed in the surface activity indices, where mid-term variations are found only from time to time and mainly in periods of high activity. This feature, together with the latitudinal dependence, provides more evidence of a mechanism that is almost independent and different from the one that brings the active regions up to the surface. Therefore, these findings can be used to provide more constraints on dynamo models that consider a further cyclic component on top of the 11-year cycle.

  18. Observations of Atmospheric Nitrogen and Phosphorus Deposition During the Period of Algal Bloom Formation in Northern Lake Taihu, China

    NASA Astrophysics Data System (ADS)

    Zhai, Shuijing; Yang, Longyuan; Hu, Weiping

    2009-09-01

    Cyanobacterial blooms in Lake Taihu occurred at the end of April 2007 and had crucial impacts on the livelihood of millions of people living there. Excessive nutrients may promote bloom formation. Atmospheric nitrogen (N) and phosphorus (P) deposition appears to play an important role in algal bloom formation. Bulk deposition and rain water samples were collected respectively from May 1 to November 30, 2007, the period of optimal algal growth, to measure the bulk atmospheric deposition rate, wet deposition rate, and dry deposition rate for total nitrogen (TN; i.e., all species of nitrogen), and total phosphorus (TP; i.e., all species of phosphorus), in northern Lake Taihu, China. The trends of the bulk atmospheric deposition rate for TN and the wet deposition rate for TN showed double peaks during the observation period and distinct influence with plum rains and typhoons. Meanwhile, monthly bulk atmospheric deposition rates for TP showed little influence of annual precipitation. However, excessive rain may lead to high atmospheric N and P deposition rates. In bulk deposition samples, the average percentage of total dissolved nitrogen accounting for TN was 91.2% and changed little with time. However, the average percentage of total dissolved phosphorus accounting for TP was 65.6% and changed substantially with time. Annual bulk atmospheric deposition rates of TN and TP during 2007 in Lake Taihu were estimated to be 2,976 and 84 kg km-2 a-1, respectively. The results showed decreases of 34.4% and 78.7%, respectively, compared to 2002-2003. Annual bulk deposition load of TN for Lake Taihu was estimated at 6,958 t a-1 in 2007 including 4,642 t a-1 of wet deposition, lower than the values obtained in 2002-2003. This may be due to measures taken to save energy and emission control regulations in the Yangtze River Delta. Nevertheless, high atmospheric N and P deposition loads helped support cyanobacterial blooms in northern Lake Taihu during summer and autumn, the period

  19. IRAS observations of Delta Scuti variables - Implications for main-sequence mass loss and an IR period-luminosity relation

    SciTech Connect

    King, J.R. )

    1990-06-01

    The far-infrared detections of Delta Scuti variables in The Bright Star Catalog by the IRAS satellite are investigated; 52 percent of the sample was detected at 12 microns. The 12 micron luminosity is correlated with L(Bol) and ranges from about 3 x 10 to the 31st to about 6 x 10 to the 32nd erg/s. Comparable numbers of Delta Sct variables and A-F nonvariables show infrared excesses in at least one IRAS passband. Further considerations show that contributions to these excesses due to mass loss are minimal. This investigation suggests that the pulsating variables are not losing mass at higher rates than nonvariable A and F stars which themselves do not appear to be losing mass at a rate above an expected level. The existence of a Period-12 micron luminosity relation of small dispersion, quite surprising in light of the uncertainties in these data is reported. It is demonstrated that such relations also exist at the J, H, and K bands. The possibility of using such relations for distance determinations is discussed in light of good distance estimates to three clusters using the P-L relation. 20 refs.

  20. Evidence of low-latitude daytime large-scale traveling ionospheric disturbances observed by high-frequency multistatic backscatter sounding system during a geomagnetically quiet period

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Zhao, Zhengyu; Yang, Guobin; Chen, Gang; Hu, Yaogai; Zhang, Yuannong

    2012-06-01

    Observations from the high-frequency multistatic backscatter sounding radars on a geomagnetically quiet day (minimum Dst = -14 nT) captured the anti-equatorward propagation of daytime large-scale traveling ionospheric disturbance (LSTID) at the low-latitude regions. The observed LSTID was characterized approximately by a meridional propagation speed of 347 ± 78 m/s and azimuthal angle of -4.7 ± 27.6° (counterclockwise from north), with a period of 76 min and a wavelength of 1583 ± 354 km by means of maximum entropy cross-spectral analysis. Vertical phase velocity was also evaluated to be <˜42 m/s through the Doppler measurements. These results provide evidence that the low-latitude ionosphere can undergo large-scale perturbations even under geomagnetically quiet conditions. We suggest that this observed LSTID could be due to the secondary gravity waves from thermospheric body forces created from the dissipation of primary gravity waves from deep tropospheric convection.

  1. Correction of humidity bias for Vaisala RS80-A and MODEM sondes during AMMA 2006 observing period

    NASA Astrophysics Data System (ADS)

    Nuret, M.; Lafore, J. P.; Bock, O.; Guichard, F.

    2009-04-01

    During the African Monsoon Multidisciplinary Analyses (AMMA) program whose Special Observing Period took place over West Africa in 2006, a major effort has been devoted to monitor the atmosphere and its water cycle. The radiosoundings network has been upgraded and enhanced, and GPS receivers deployed. The various sondes used in the campaign exhibit a significant humidity bias: • dry bias for Vaisala RS80-A at daytime and nighttime, for RS92 and MODEM M2K2 at daytime only • moist bias for MODEM M2K2 and Vaisala RS92 at nighttime This presentation makes use of a simple but robust statistical approach to correct the bias. Validation against independent GPS data shows that a first correction (to be implemented in the database in early 2009), removes the night bias for MODEM and Vaisala RS-80A, and strongly reduces it for daytime RS80-A launches. The correction dramatically modifies the CAPE, which becomes much more in line with expected values over the region. A second correction (under development) will address the remaining daytime bias, thanks to an inter-comparison exercise performed in Niamey in September 2008.

  2. Comparison of Columnar Water Vapor Measurements During The Fall 1997 ARM Intensive Observation Period: Solar Transmittance Methods

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Michalsky, J. J.; Slater, D. W.; Barnard, J. C.; Halthore, R. N.; Liljegren, J. C.; Holben, B. N.; Eck, T. F.; Livingston, J. M.; Russell, P. B.

    2000-01-01

    In the fall of 1997, during an Intensive Observation Period (IOP), the Atmospheric Radiation Measurement (ARM) program conducted a study of water vapor abundance measurement at its Southern Great Plains (SGP) site. Among a large number of instruments, four sun-tracking radiometers were present to measure the columnar water vapor (CWV). All four solar radiometers retrieve CWV by measuring total solar transmittance in the 0.94-gm water vapor absorption band and subtracting contributions due to Rayleigh, ozone and aerosol transmittances. The aerosol optical depth comparisons among the same four radiometers has been presented elsewhere (Geophys. Res. Lett., 26, 17, 2725-2728, 1999). We have used three different methods to retrieve CWV. In a first round of comparison no attempt was made to standardize on the same radiative transfer model and its underlying water vapor spectroscopy. In the second round of comparison we used the same line-by-line code (which includes recently corrected H2O spectroscopy) to retrieve CAN from all four suntracking radiometers. This decreased the mean CWV by 8% or 13%. The spread of 8% in the solar radiometer results found when using the same model is an indication of the other-than-model uncertainties involved in determining CWV from solar transmittance measurements with current instrumentation.

  3. The features of sporadic hyperbolic meteors observed by television techniques in the period of 2007-2009

    NASA Astrophysics Data System (ADS)

    Guliyev, Ayyub; Nabiyev, Shaig

    2015-12-01

    The features of 238 hyperbolic meteors observed within the framework of the Japanese program SonotaCo in the period of 2007-2009 are investigated in this paper. Irregularity of the eccentricities, explicitly dominance of retrograde orbits over direct ones, absence of domination of perihelia closes the ecliptic, irregular distribution of angular elements for these bodies' orbits were noticed. The values of eccentricities are distributed in the interval from 1 up to 1.31. The significant concentration of these particles perihelia closes the anti-apex of the Sun's peculiarity movements in the Galaxy was noticed. Distribution of elements of orbits in the galactic system of coordinates was considered also, however it was not possible to find the appreciable regularities. The distributions of the distant nodes and MOID-Minimum Orbit Intersection Distance of the hyperbolic meteors relatively to the orbits of the planets-giants were investigated as well. However it was not possible to prove, that the majority of the particles could receive the hyperbolic excess of speed due to the gravitational influence of the planets-giants. The statistics of relation of the hyperbolic meteors with 14 known trans-Neptunian planetary bodies brighter 3m.5 is considered. Testing of the distant nodes and MOID values only for 2003 MW12, 2007 OR10 and Qaoaor have the positive results. In the next stage we have made analogical calculations for the 78 TNO having absolute brightness 5m.5 also and obtained the reasonable results for 9 of them.

  4. Remote Cloud Sensing Intensive Observation Period (RCS-IOP) millimeter-wave radar calibration and data intercomparison

    SciTech Connect

    Sekelsky, S.M.; Firda, J.M.; McIntosh, R.E.

    1996-04-01

    During April 1994, the University of Massachusetts (UMass) and the Pennsylvania State University (Penn State) fielded two millimeter-wave atmospheric radars in the Atmospheric Radiation Measurement Remote Cloud Sensing Intensive Operation Period (RCS-IOP) experiment. The UMass Cloud Profiling Radar System (CPRS) operates simultaneously at 33.12 GHz and 94.92 GHz through a single antenna. The Penn State radar operates at 93.95 GHz and has separate transmitting and receiving antennas. The two systems were separated by approximately 75 meters and simultaneously observed a variety of cloud types at verticle incidence over the course of the experiment. This abstract presents some initial results from our calibration efforts. An absolute calibration of the UMass radar was made from radar measurements of a trihedral corner reflector, which has a known radar cross-section. A relative calibration of between the Penn State and UMass radars is made from the statistical comparison of zenith pointing measurements of low altitude liquid clouds. Attenuation is removed with the aid of radiosonde data, and the difference in the calibration between the UMass and Penn State radars is determined by comparing the ratio of 94-GHz and 95-GHz reflectivity values to a model that accounts for parallax effects of the two antennas used in the Penn State system.

  5. Intestinal stoma in patients with colorectal cancer from the perspective of 20-year period of clinical observation

    PubMed Central

    Banaszkiewicz, Zbigniew; Woda, Łukasz P.; Tojek, Krzysztof; Jarmocik, Paweł; Jawień, Arkadiusz

    2015-01-01

    Introduction Intestinal stoma is a procedure most often performed in patients with colorectal cancer. Aim To identify the percentage of patients with colorectal cancer in which the intestinal stoma was performed. Material and methods We retrospectively analysed 443 patients treated during a 20-year period (1994–2013) due to colorectal cancer, in which the intestinal stoma was made during the first surgical intervention. Results In the second analysed decade, a significant decrease in the percentage of created stomas, definitive stomas in particular, was observed. Stomas were made significantly more often in patients with a tumour located in the rectum, the left half of the colon, and in patients undergoing urgent surgeries. An increased incidence of intestinal stomas was associated with a higher severity of illness and higher proportion of unresectable and non-radical procedures. The definitive stomas were significantly more often made in men and in patients with tumours located in the rectum, whereas temporary stomas were created significantly more often in patients undergoing urgent operations. Conclusions In the last decade (2004–2013) the number of intestinal stomas in patients operated due to colorectal cancer was significantly reduced. PMID:25960811

  6. Seismic observations of long-period ocean waves generated by calving icebergs, Jakobshavn Isbræ, Greenland

    NASA Astrophysics Data System (ADS)

    Amundson, J. M.; Truffer, M.; Fahnestock, M. A.; Holland, D. M.; Luethi, M. P.; Motyka, R. J.; Clinton, J. F.; Macayeal, D. R.

    2010-12-01

    Tide gauges and broadband coastal seismometers regularly record low-frequency (0.001-0.01 Hz) ocean waves generated by large calving icebergs at Jakobshavn Isbræ, Greenland. The waves are observed up to 150 km from the glacier terminus, first arrive at the stations 10-30 minutes after calving initiates, can persist for several hours, and have distinct spectral peaks that vary between stations but not between calving events (suggestive of basin eigenmodes). The unique characteristics of the waves can be used to confidently identify large calving events. Furthermore, the energy of the waves can be used to estimate the size of a calving event and, if used in conjunction with visual imagery, place a maximum bound on the amount of energy lost to the ocean via turbulence and dissipation. Although the ocean wave signal is most easily identifiable in tide gauge data, seismometers have the added benefits of recording (1) very broadband seismic signals, including higher frequency (e.g., 2-5 Hz) seismic signals from calving events (not just their aftermath), (2) ocean waves in ice-choked fjords and bays that are impossible to instrument with tide gauges, and (3) continuous, real time signals over multiple years. We will present examples from Jakobshavn Isbræ to demonstrate how observations of calving-generated ocean waves can be used to gain insights into glaciologically-relevant processes.

  7. The HyMeX Special Observation Period in Central Italy: precipitation measurements, retrieval techniques and preliminary results

    NASA Astrophysics Data System (ADS)

    Silvio Marzano, Frank; Baldini, Luca; Picciotti, Errico; Colantonio, Matteo; Barbieri, Stefano; Di Fabio, Saverio; Montopoli, Mario; Vulpiani, Gianfranco; Roberto, Nicoletta; Adirosi, Elisa; Gorgucci, Eugenio; Anagnostou, Marios N.; Kalogiros, John; Anagnostou, Emmanouil N.; Ferretti, Rossella; Gatlin, Patrick.; Wingo, Matt; Petersen, Walt

    2013-04-01

    The Mediterranean area concentrates the major natural risks related to the water cycle, including heavy precipitation and flash-flooding during the fall season. The capability to predict such high-impact events remains weak because of the contribution of very fine-scale processes and their non-linear interactions with the larger scale processes. These societal and science issues motivate the HyMeX (Hydrological cycle in the Mediterranean Experiment, http://www.hymex.org/) experimental programme. HyMeX aims at a better quantification and understanding of the water cycle in the Mediterranean with emphasis on intense events. The observation strategy of HyMEX is organized in a long-term (4 years) Enhanced Observation Periods (EOP) and short-term (2 months) Special Observation Periods (SOP). HyMEX has identified 3 main Mediterranean target areas: North-West (NW), Adriatic (A) and South-East (SE). Within each target area several hydrometeorological sites for heavy rainfall and flash flooding have been set up. The hydrometeorological site in Central Italy (CI) is interested by both western and eastern fronts coming from the Atlantic Ocean and Siberia, respectively. Orographic precipitations play an important role due to the central Apennine range, which reaches nearly 3000 m (Gran Sasso peak). Moreover, convective systems commonly develop in CI during late summer and beginning of autumn, often causing localized hailstorms with cluster organized cells. Western fronts may heavily hit the Tiber basin crossing large urban areas (Rome), whereas eastern fronts can cause flash floods along the Adriatic coastline. Two major basins are involved within CI region: Tiber basin (1000 km long) and its tributary Aniene and the Aterno-Pescara basin (300 km long). The first HyMeX SOP1.1 was carried out from Sept. till Nov. 2012 in the NW target area. The Italian SOP1.1 was coordinated by the Centre of Excellence CETEMPS, University of L'Aquila, a city located in the CI heart. The CI area

  8. The HyMeX Special Observation Period in Central Italy: Precipitation Measurements, Retrieval Techniques and Preliminary Results

    NASA Technical Reports Server (NTRS)

    Gatlin, Patrick; Wingo, Matt; Petersen, Walt; Marzano, Frank Silvio; Baldini, Luca; Picciotti, Errico; Colantonio, Matteo; Barbieri, Stefano; Di Fabio, Saverio; Montopoli, Mario; Roberto, Nicoletta; Adirosi, Elisa; Gorgucci, Eugenio; Anagnostou, Emmanoil N..; Ferretti, Rossella

    2013-01-01

    The Mediterranean area concentrates the major natural risks related to the water cycle, including heavy precipitation and flash-flooding during the fall season. The capability to predict such high-impact events remains weak because of the contribution of very fine-scale processes and their non-linear interactions with the larger scale processes. These societal and science issues motivate the HyMeX (Hydrological cycle in the Mediterranean Experiment, http://www.hymex.orgl) experimental programme. HyMeX aims at a better quantification and understanding of the water cycle in the Mediterranean with emphasis on intense events. The observation strategy of HyMEX is organized in a long-term (4 years) Enhanced Observation Periods (EOP) and short-term (2 months) Special Observation Periods (SOP). HyMEX has identified 3 main Mediterranean target areas: North-West (NW), Adriatic (A) and South-East (SE). Within each target area several hydrometeorological sites for heavy rainfall and flash flooding have been set up. The hydrometeorological sire in Central Italy (CI) is interested by both western and eastern fronts coming from the Atlantic Ocean and Siberia, respectively. Orographic precipitations play an important role due to the central Apennine range, which reaches nearly 3000 m (Gran Sasso peak). Moreover, convective systems commonly develop in CI during late summer and beginning of autumn, often causing localized hailstorms with cluster organized cells. Western fronts may heavily hit the Tiber basin crossing large urban areas (Rome), whereas eastern fronts can cause flash floods along the Adriatic coastline. Two major basins are involved within Cl region: Tiber basin (1000 km long) and its tributary Aniene and the Aterno-Pescara basin (300 km long). The first HyMeX SOP1.1 was carried out from Sept. till Nov. 2012 in the NW target area The Italian SOP1.1 was coordinated by the Centre of Excellence CETEMPS, University of L'Aquila, a city located in the CI heart. The CI area

  9. Trends and projections of temperature, precipitation, and snow cover during snow cover-observed period over southwestern Iran

    NASA Astrophysics Data System (ADS)

    Zarenistanak, Mohammad; Dhorde, Amit G.; Kripalani, R. H.; Dhorde, Anargha A.

    2015-11-01

    In the present study, tendencies in temperature, precipitation, and snow cover area over the southwestern part of Iran have been assessed. The research mainly focused on snow cover-observed period which included the months of December, January, February, March, and April in the area. This research has been divided into two parts. First part consists of an analysis of the trends in temperature, precipitation, and snow cover area during the above months. Trends in these parameters were tested by linear regression, and significance was determined by t test. Mann-Kendall rank test (MK test) was also employed to confirm the results of linear regression. Sequential Mann-Kendall test (SQ-MK test) was applied for change point detection in the series. For snow cover analysis, remote sensing images from National Oceanic and Atmospheric Administration (NOAA) satellite with advanced very high resolution radiometer (AVHRR) sensor for the period 1987-2007 were used. The second part of the research involved future projections based on four models under B1 and A1B emission scenarios. The models used were centre national de recherches meteorologiques (CNRM), European Center Hamburg model (ECHAM), Model for Interdisciplinary Research on Climate (MIROCH) and United Kingdom Meteorological Office (UKMOC) under the Intergovernmental Panel on Climate Change (IPCC) AR4. The analysis of temperature trends revealed a significant increase during February and April. Temperature projections showed that temperature may increase between 1.12 to 7.87 °C by 2100 in the study area. The results of precipitation series indicated that majority of the stations registered insignificant trends during the twentieth century. However, precipitation may decrease according to most of the models under both scenarios, but the decrease may not be large, except according to MIROCH model. The results of trend analysis of snow cover area indicated that no significant trends were detected by any statistical tests

  10. Combined ligand-observe 19F and protein-observe 15N,1H-HSQC NMR suggests phenylalanine as the key Δ-somatostatin residue recognized by human protein disulfide isomerase

    PubMed Central

    Richards, Kirsty L.; Rowe, Michelle L.; Hudson, Paul B.; Williamson, Richard A.; Howard, Mark J.

    2016-01-01

    Human protein disulphide isomerase (hPDI) is an endoplasmic reticulum (ER) based isomerase and folding chaperone. Molecular detail of ligand recognition and specificity of hPDI are poorly understood despite the importance of the hPDI for folding secreted proteins and its implication in diseases including cancer and lateral sclerosis. We report a detailed study of specificity, interaction and dissociation constants (Kd) of the peptide-ligand Δ-somatostatin (AGSKNFFWKTFTSS) binding to hPDI using 19F ligand-observe and 15N,1H-HSQC protein-observe NMR methods. Phe residues in Δ-somatostatin are hypothesised as important for recognition by hPDI therefore, step-wise peptide Phe-to-Ala changes were progressively introduced and shown to raise the Kd from 103 + 47 μM until the point where binding was abolished when all Phe residues were modified to Ala. The largest step-changes in Kd involved the F11A peptide modification which implies the C-terminus of Δ-somatostatin is a prime recognition region. Furthermore, this study also validated the combined use of 19F ligand-observe and complimentary 15N,1H-HSQC titrations to monitor interactions from the protein’s perspective. 19F ligand-observe NMR was ratified as mirroring 15N protein-observe but highlighted the advantage that 19F offers improved Kd precision due to higher spectrum resolution and greater chemical environment sensitivity. PMID:26786784

  11. Field Observation of Heterogeneous Formation of Dicarboxylic acids, Keto-carboxylic acids, α-Dicarbonyls and Nitrate in Xi'an, China during Asian dust storm periods

    NASA Astrophysics Data System (ADS)

    Wang, G.; Wang, J.; Ren, Y.; Li, J.

    2015-12-01

    To understand the formation mechanism of secondary organic aerosols (SOA) on dust surfaces, this study investigated the concentrations and compositions of dicarboxylic acids (C2-C11), keto-carboxylic acids (C3-C7), α-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) collected in Xi'an, China during the nondust storm and dust storm periods of 2009 and 2011. During the events the ambient particulate dicarboxylic acids were 932-2240 ng m-3, which are comparable and even higher than those in nondust periods. Molecular compositions of the above SOA are similar to those in nondust periods with oxalic acid being the leading species. In the presence of the dust storms, all the above mentioned SOA species in Xi'an were predominantly enriched on the coarse particles (>2.1μm), and oxalic acid well correlated with NO3- (R2=0.72, p<0.001) rather than SO42-.This phenomenon differs greatly from the SOA in any other nondust period that is characterized by an enrichment of oxalic acid in fine particles and a strong correlation of oxalic acid with SO42-. Our results further demonstrate that NO3- in the dust periods in Xi'an was mostly derived from secondary oxidation, whereas SO42- during the events was largely derived from surface soil of Gobi deserts. We propose a formation pathway to explain these observations, in which nitric acid and/or nitrogen oxides react with dust to produce Ca(NO3)2 and form a liquid phase on the surface of dust aerosols via water vapor-absorption of Ca(NO3)2, followed by a partitioning of the gas-phase water-soluble organic precursors (e.g.,glyoxal and methylglyoxal) into the aqueous-phase and a subsequent oxidation into oxalic acid. To the best of our knowledge, we found for the first time the enrichment of glyoxal and methylglyoxal on dust surface. Our data suggest an important role of nitrate in the heterogeneous formation process of SOA on the surface of Asian dust.

  12. Detecting multiple periodicities in observational data with the multifrequency periodogram - I. Analytic assessment of the statistical significance

    NASA Astrophysics Data System (ADS)

    Baluev, Roman V.

    2013-11-01

    We consider the `multifrequency' periodogram, in which the putative signal is modelled as a sum of two or more sinusoidal harmonics with independent frequencies. It is useful in cases when the data may contain several periodic components, especially when their interaction with each other and with the data sampling patterns might produce misleading results. Although the multifrequency statistic itself was constructed earlier, for example by G. Foster in his CLEANest algorithm, its probabilistic properties (the detection significance levels) are still poorly known and much of what is deemed known is not rigorous. These detection levels are nonetheless important for data analysis. We argue that to prove the simultaneous existence of all n components revealed in a multiperiodic variation, it is mandatory to apply at least 2n - 1 significance tests, among which most involve various multifrequency statistics, and only n tests are single-frequency ones. The main result of this paper is an analytic estimation of the statistical significance of the frequency tuples that the multifrequency periodogram can reveal. Using the theory of extreme values of random fields (the generalized Rice method), we find a useful approximation to the relevant false alarm probability. For the double-frequency periodogram, this approximation is given by the elementary formula (π/16)W2e- zz2, where W denotes the normalized width of the settled frequency range, and z is the observed periodogram maximum. We carried out intensive Monte Carlo simulations to show that the practical quality of this approximation is satisfactory. A similar analytic expression for the general multifrequency periodogram is also given, although with less numerical verification.

  13. Estimating Asian terrestrial carbon fluxes from CONTRAIL aircraft and surface CO2 observations for the period 2006-2010

    NASA Astrophysics Data System (ADS)

    Zhang, H. F.; Chen, B. Z.; Machida, T.; Matsueda, H.; Sawa, Y.; Fukuyama, Y.; Langenfelds, R.; van der Schoot, M.; Xu, G.; Yan, J. W.; Cheng, M. L.; Zhou, L. X.; Tans, P. P.; Peters, W.

    2014-06-01

    Current estimates of the terrestrial carbon fluxes in Asia show large uncertainties particularly in the boreal and mid-latitudes and in China. In this paper, we present an updated carbon flux estimate for Asia ("Asia" refers to lands as far west as the Urals and is divided into boreal Eurasia, temperate Eurasia and tropical Asia based on TransCom regions) by introducing aircraft CO2 measurements from the CONTRAIL (Comprehensive Observation Network for Trace gases by Airline) program into an inversion modeling system based on the CarbonTracker framework. We estimated the averaged annual total Asian terrestrial land CO2 sink was about -1.56 Pg C yr-1 over the period 2006-2010, which offsets about one-third of the fossil fuel emission from Asia (+4.15 Pg C yr-1). The uncertainty of the terrestrial uptake estimate was derived from a set of sensitivity tests and ranged from -1.07 to -1.80 Pg C yr-1, comparable to the formal Gaussian error of ±1.18 Pg C yr-1 (1-sigma). The largest sink was found in forests, predominantly in coniferous forests (-0.64 ± 0.70 Pg C yr-1) and mixed forests (-0.14 ± 0.27 Pg C yr-1); and the second and third large carbon sinks were found in grass/shrub lands and croplands, accounting for -0.44 ± 0.48 Pg C yr-1 and -0.20 ± 0.48 Pg C yr-1, respectively. The carbon fluxes per ecosystem type have large a priori Gaussian uncertainties, and the reduction of uncertainty based on assimilation of sparse observations over Asia is modest (8.7-25.5%) for most individual ecosystems. The ecosystem flux adjustments follow the detailed a priori spatial patterns by design, which further increases the reliance on the a priori biosphere exchange model. The peak-to-peak amplitude of inter-annual variability (IAV) was 0.57 Pg C yr-1 ranging from -1.71 Pg C yr-1 to -2.28 Pg C yr-1. The IAV analysis reveals that the Asian CO2 sink was sensitive to climate variations, with the lowest uptake in 2010 concurrent with a summer flood and autumn drought and the largest

  14. Pulsations and period changes of the non-Blazhko RR lyrae variable Y oct observed from Dome A, Antarctica

    SciTech Connect

    Zhihua, Huang; Jianning, Fu; Weikai, Zong; Lingzhi, Wang; Zonghong, Zhu; M, Macri Lucas; Lifan, Wang; Ashley, Michael C. B.; S, Lawrence Jon; Daniel, Luong-Van; Xiangqun, Cui; Long-Long, Feng; Xuefei, Gong; Qiang, Liu; Huigen, Yang; Xiangyan, Yuan; Xu, Zhou; Zhenxi, Zhu; R, Pennypacker Carl; G, York Donald

    2015-01-01

    During the operation of the Chinese Small Telescope Array (CSTAR) in Dome A of Antarctica in the years 2008, 2009, and 2010, large amounts of photometric data have been obtained for variable stars in the CSTAR field. We present here the study of one of six RR Lyrae variables, Y Oct, observed with CSTAR in Dome A, Antarctica. Photometric data in the i band were obtained in 2008 and 2010, with a duty cycle (defined as the fraction of time representing scientifically available data to CSTAR observation time) of about 44% and 52%, respectively. In 2009, photometric data in the g and r bands were gathered for this star, with a duty cycle of 65% and 60%, respectively. Fourier analysis of the data in the three bands only shows the fundamental frequency and its harmonics, which is characteristic of the non-Blazhko RR Lyrae variables. Values of the fundamental frequency and the amplitudes, as well as the total pulsation amplitude, are obtained from the data in the three bands separately. The amplitude of the fundamental frequency and the total pulsation amplitude in the g band are the largest, and those in the i band the smallest. Two-hundred fifty-one times of maximum are obtained from the three seasons of data, which are analyzed together with 38 maximum times provided in the GEOS RR Lyrae database. A period change rate of −0.96 ± 0.07 days Myr{sup −1} is then obtained, which is a surprisingly large negative value. Based on relations available in the literature, the following physical parameters are derived: [Fe/H] = −1.41 ± 0.14, M{sub V} = 0.696 ± 0.014 mag, V−K = 1.182 ± 0.028 mag, logT{sub eff} = 3.802 ± 0.003 K, logg = 2.705 ± 0.004, logL/L{sub ⊙} = 1.625 ± 0.013, and logM/M{sub ⊙} = −0.240 ± 0.019.

  15. A Comparison of Observationally Determined Radii with Theoretical Radius Predictions for Short-Period Transiting Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Laughlin, Gregory; Wolf, Aaron; Vanmunster, Tonny; Bodenheimer, Peter; Fischer, Debra; Marcy, Geoff; Butler, Paul; Vogt, Steve

    2005-03-01

    Two extrasolar planets, HD 209458b and TrES-1, are currently known to transit bright parent stars for which physical properties can be accurately determined. The two transiting planets have very similar masses and periods and hence invite detailed comparisons between their observed and theoretically predicted properties. In this paper, we carry out these comparisons. We first report photometric and spectroscopic follow-up observations of TrES-1, and we use these observations to obtain improved estimates for the planetary radius, Rpl=(1.08+/-0.05)RJ, and the planetary mass, Mpl=(0.729+/-0.036)MJ. We also confirm that the inclination estimate of the planetary orbit as i=88.2d. These values agree with those obtained by Alonso et al. in their discovery paper, but the uncertainty in the planet radius has been improved as a result of both high-cadence photometry of two full transits and from independent radius determinations for the V=11.8 K0 V parent star. We derive estimates for the TrES-1 stellar parameters of R*/Rsolar=0.83+/-0.03 (by combining independent estimates from stellar models, high-resolution spectra, and transit light curve fitting) M*/Msolar=0.87+/-0.05 (via fitting to evolutionary tracks), Teff=5214+/-23K, [Me/H]=0.001+/-0.04, rotational velocity Vsin(i)=1.08+/-0.3kms-1, logg=4.52+/-0.05dex, logL*/Lsolar=-0.32, d=157+/-6pc, and an age of τ=4+/-2Gyr. These estimates of the physical properties of the system allow us to compute evolutionary models for the planet that result in a predicted radius of Rpl=1.05RJ for a model that contains an incompressible 20 M⊕ core and a radius Rpl=1.09RJ for a model without a core. We use our grids of planetary evolution models to show that, with standard assumptions, our code also obtains good agreement with the observed radii of the other recently discovered transiting planets, including OGLE-TR-56b, OGLE-TR-111b, OGLE-TR-113b, and OGLE-TR-132b. We report an updated radius for HD 209458b of Rpl=(1.32+/-0.05)RJ, based on

  16. Hypnosis, suggestion, and suggestibility: an integrative model.

    PubMed

    Lynn, Steven Jay; Laurence, Jean-Roch; Kirsch, Irving

    2015-01-01

    This article elucidates an integrative model of hypnosis that integrates social, cultural, cognitive, and neurophysiological variables at play both in and out of hypnosis and considers their dynamic interaction as determinants of the multifaceted experience of hypnosis. The roles of these variables are examined in the induction and suggestion stages of hypnosis, including how they are related to the experience of involuntariness, one of the hallmarks of hypnosis. It is suggested that studies of the modification of hypnotic suggestibility; cognitive flexibility; response sets and expectancies; the default-mode network; and the search for the neurophysiological correlates of hypnosis, more broadly, in conjunction with research on social psychological variables, hold much promise to further understanding of hypnosis. PMID:25928681

  17. Impact of Asian dust and continental pollutants on cloud chemistry observed in northern Taiwan during the experimental period of ABC/EAREX 2005

    NASA Astrophysics Data System (ADS)

    Wang, Sheng-Hsiang; Lin, Neng-Huei; Ouyang, Chang-Feng; Wang, Jia-Lin; Campbell, James R.; Peng, Chi-Ming; Lee, Chung-Te; Sheu, Guey-Rong; Tsay, Si-Chee

    2010-04-01

    Observations of particulate matter (PM), vertical cloud and aerosol structure and cloud water chemistry in northern Taiwan were conducted during the ABC/EAREX 2005 period. Five Asian continental outflow regimes reaching Taiwan were identified. One was coupled with a dust storm observed not only at Gosan, Korea, but also over Taiwan, suggesting the scope of its regional impact. The arrival of the dust event was determined by lidar, cloud water, and surface PM measurements. When continental outflow events correspond to the presence of significant dust concentrations, air quality can be drastically worsened due to high levels of PM. PM10 (PM with aerodynamic diameters < 10 μm), pH, conductivity, and ion concentrations of cloud water increased drastically near the dissipating stage of the frontal passage/cloud event for the dust case. Cloud water may have become acidified by pollution from industrial and urban regions along the coast of eastern China. Nevertheless, abundant Ca2+ contributed to the neutralization of acidic cloud water during the dust stage. The much higher aerosol and chemical loading injected into these clouds caused an enrichment effect in the cloud water, which can double the cloud loading of total ions, when Ca2+ increases by approximately 7 times.

  18. What Are the Trends in Tonsillectomy Techniques in Wales? A Prospective Observational Study of 19,195 Tonsillectomies over a 10-Year Period

    PubMed Central

    Walijee, Hussein; Al-Hussaini, Ali; Harris, Andrew; Owens, David

    2015-01-01

    There are a multitude of techniques to undertake tonsillectomy, with hot techniques such as diathermy and coblation being associated with a higher risk of secondary haemorrhage. The UK National Prospective Tonsillectomy Audit (2004) advocated cold steel dissection and ties to be the gold standard. This prospective observational study investigates the trends in tonsillectomy techniques across Wales in the last decade to establish if surgeons have adhered to this national guidance. Data relating to tonsillectomy were extracted over a 10-year period from 1 January 2003 to 31 December 2012 from the Wales Surgical Instrument Surveillance Programme database. A total of 19,195 patients were included. Time-series analysis using linear regression showed there was an increase in the number of bipolar diathermy tonsillectomies by 84% (Pearson's r = 0.762, p = 0.010) and coblation tonsillectomies by 120% (r = 0.825, p = 0.003). In contrast, there was a fall in the number of cold steel dissection tonsillectomies with ties by 60% (r = −0.939, p < 0.001). This observational study suggests that the use of bipolar and coblation techniques for tonsillectomy has increased. This deviation from national guidance may be due to these techniques being faster with less intraoperative bleeding. Further study for the underlying reasons for the increase in these techniques is warranted. PMID:26693228

  19. Mercury - Thermal emission at radio wavelengths. I - 3.3- and 28-mm observed brightness temperatures and periodicities therein

    NASA Technical Reports Server (NTRS)

    Epstein, E. E.; Andrew, B. H.

    1985-01-01

    The thermal radio emission from Mercury at 3.3 mm and 28 mm was measured over a period of several years, and the results of a statistical analysis of the data are reported. The disk-average brightness temperature is reported as a function of longitude, and other periodicities are reported. The range of values of the thermophysical parameters is constrained by comparing the data with models.

  20. Estimating Asian terrestrial carbon fluxes from CONTRAIL aircraft and surface CO2 observations for the period 2006 to 2010

    NASA Astrophysics Data System (ADS)

    Zhang, H. F.; Chen, B. Z.; van der Laan-Luijkx, I. T.; Machida, T.; Matsueda, H.; Sawa, Y.; Fukuyama, Y.; Labuschagne, C.; Langenfelds, R.; van der Schoot, M.; Xu, G.; Yan, J. W.; Zhou, L. X.; Tans, P. P.; Peters, W.

    2013-10-01

    Current estimates of the terrestrial carbon fluxes in Asia ("Asia" refers to lands as far west as the Urals and is divided into Boreal Eurasia, Temperate Eurasia and tropical Asia based on TransCom regions) show large uncertainties particularly in the boreal and mid-latitudes and in China. In this paper, we present an updated carbon flux estimate for Asia by introducing aircraft CO2 measurements from the CONTRAIL (Comprehensive Observation Network for Trace gases by Airline) program into an inversion modeling system based on the CarbonTracker framework. We estimated the averaged annual total Asian terrestrial land CO2 sink was about -1.56 Pg C yr-1 over the period 2006-2010, which offsets about one-third of the fossil fuel emission from Asia (+4.15 Pg C yr-1). The uncertainty of the terrestrial uptake estimate was derived from a set of sensitivity tests and ranged from -1.07 to -1.80 Pg C yr-1, comparable to the formal Gaussian error of ±1.18 Pg C yr-1 (1-sigma). The largest sink was found in forests, predominantly in coniferous forests (-0.64 Pg C yr-1) and mixed forests (-0.14 Pg C yr-1); and the second and third large carbon sinks were found in grass/shrub lands and crop lands, accounting for -0.44 Pg C yr-1 and -0.20 Pg C yr-1, respectively. The peak-to-peak amplitude of inter-annual variability (IAV) was 0.57 Pg C yr-1 ranging from -1.71 Pg C yr-1 to -2.28 Pg C yr-1. The IAV analysis reveals that the Asian CO2 sink was sensitive to climate variations, with the lowest uptake in 2010 concurrent with summer flood/autumn drought and the largest CO2 sink in 2009 owing to favorable temperature and plentiful precipitation conditions. We also found the inclusion of the CONTRAIL data in the inversion modeling system reduced the uncertainty by 11% over the whole Asian region, with a large reduction in the southeast of Boreal Eurasia, southeast of Temperate Eurasia and most Tropical Asian areas.

  1. Dynamics of CO2-exchange and C-budgets due to soil erosion: Insights from a 4 years observation period

    NASA Astrophysics Data System (ADS)

    Hoffmann, Mathias; Albiac Borraz, Elisa; Garcia Alba, Juana; Augustin, Jürgen; Sommer, Michael

    2015-04-01

    Agriculture in the hummocky ground moraine landscape of NE-Germany is characterized by an increase in energy crop cultivation, like maize or sorghum. Both enhance lateral C fluxes by erosion and induce feedbacks on C dynamics of agroecosystems as a result of reduced wintertime plant cover and vigorous crop growth during summer. However, the actual impact of these phenomena on the CO2-sink/-source function of agricultural landscapes, is still not clear. Therefore, the interdisciplinary project "CarboZALF" was established in Dedelow/Prenzlau (NE-Germany) in 2009. Within the field experiment CarboZALF-D, CO2 fluxes for the soil-plant systems were monitored, covering typical landscape relevant soil states in respect to erosion and deposition, like Calcic Cutanic Luvisol and Endogleyic Colluvic Regosol. Automated chamber systems, each consisting of four transparent chambers (2.5 m height, basal area 2.25 m2), were placed along gradients at both measurement sites. Monitored CO2 fluxes were gap-filled on a high-temporal resolution by modelling ecosystem respiration (Reco), gross primary productivity (GPP) and net ecosystem exchange (NEE) based on parallel and continuous measurements of the CO2 exchange, soil and air temperatures as well as photosynthetic active radiation (PAR). Gap-filling was e.g. needed in case of chamber malfunctions and abrupt disturbances by farming practice. The monitored crop rotation was corn-winter wheat (2 a), sorghum-winter triticale and alfalfa (1.5 a). In our presentation we would like to show insights from a 4 years observation period, with prounounced differences between the eroded and the colluvial soil: The Endogleyic Colluvic Regosol showed higher flux rates for Reco, GPP and NEE compared to the Calcic Cutanic Luvisol. Site-specific NEE and C-balances were positively related to soil C-stocks as well as biomass production, and generated a minor C-sink in case of the Calcic Cutanic Luvisol and a highly variable C-source in case of the

  2. Non-equilibrium ionization by a periodic electron beam. I. Synthetic coronal spectra and implications for interpretation of observations

    NASA Astrophysics Data System (ADS)

    Dzifčáková, E.; Dudík, J.; Mackovjak, Š.

    2016-05-01

    Context. Coronal heating is currently thought to proceed via the mechanism of nanoflares, small-scale and possibly recurring heating events that release magnetic energy. Aims: We investigate the effects of a periodic high-energy electron beam on the synthetic spectra of coronal Fe ions. Methods: Initially, the coronal plasma is assumed to be Maxwellian with a temperature of 1 MK. The high-energy beam, described by a κ-distribution, is then switched on every period P for the duration of P/ 2. The periods are on the order of several tens of seconds, similar to exposure times or cadences of space-borne spectrometers. Ionization, recombination, and excitation rates for the respective distributions are used to calculate the resulting non-equilibrium ionization state of Fe and the instantaneous and period-averaged synthetic spectra. Results: Under the presence of the periodic electron beam, the plasma is out of ionization equilibrium at all times. The resulting spectra averaged over one period are almost always multithermal if interpreted in terms of ionization equilibrium for either a Maxwellian or a κ-distribution. Exceptions occur, however; the EM-loci curves appear to have a nearly isothermal crossing-point for some values of κs. The instantaneous spectra show fast changes in intensities of some lines, especially those formed outside of the peak of the respective EM(T) distributions if the ionization equilibrium is assumed. Movies 1-5 are available in electronic form at http://www.aanda.org

  3. Non-equilibrium ionization by a periodic electron beam. I. Synthetic coronal spectra and implications for interpretation of observations

    NASA Astrophysics Data System (ADS)

    Dzifčáková, E.; Dudík, J.; Mackovjak, Š.

    2016-04-01

    Context. Coronal heating is currently thought to proceed via the mechanism of nanoflares, small-scale and possibly recurring heating events that release magnetic energy. Aims: We investigate the effects of a periodic high-energy electron beam on the synthetic spectra of coronal Fe ions. Methods: Initially, the coronal plasma is assumed to be Maxwellian with a temperature of 1 MK. The high-energy beam, described by a κ-distribution, is then switched on every period P for the duration of P/ 2. The periods are on the order of several tens of seconds, similar to exposure times or cadences of space-borne spectrometers. Ionization, recombination, and excitation rates for the respective distributions are used to calculate the resulting non-equilibrium ionization state of Fe and the instantaneous and period-averaged synthetic spectra. Results: Under the presence of the periodic electron beam, the plasma is out of ionization equilibrium at all times. The resulting spectra averaged over one period are almost always multithermal if interpreted in terms of ionization equilibrium for either a Maxwellian or a κ-distribution. Exceptions occur, however; the EM-loci curves appear to have a nearly isothermal crossing-point for some values of κs. The instantaneous spectra show fast changes in intensities of some lines, especially those formed outside of the peak of the respective EM(T) distributions if the ionization equilibrium is assumed. Movies 1-5 are available in electronic form at http://www.aanda.org

  4. Observations of Periodic Comet 2P/Encke: Physical Properties of the Nucleus and First Visual-Wavelength Detection of Its Dust Trail

    NASA Technical Reports Server (NTRS)

    Lowry, Stephen C.; Weissman, Paul R.; Sykes, Mark V.; Reach, William T.

    2003-01-01

    We are conducting an observational program designed to determine the overall distributions of size, shape, rotation period, and surface characteristics of cometary nuclei. Here, we present results from a study of the Jupiter- family comet 2P/Encke based on observations from Steward Observatory's 2.3m Bok Telescope at Kitt Peak. This comet has been observed extensively in the past and was one of the primary flyby targets of the recently failed CONTOUR mission.

  5. Observation of the period ratio P 1/ P 2 of transversal oscillations in solar macro-spicules

    NASA Astrophysics Data System (ADS)

    Ebadi, H.; Khoshrangbaf, M.

    2014-08-01

    We analyze the time series of oxygen line profiles (O vi 1031.93 Å and O vi 1037.61 Å) obtained from SUMER/SOHO on the solar south limb. We calculated Doppler shifts and consequently Doppler velocities in three heights 4″, 14″, and 24″ from the limb on a coronal hole region. Then, we performed wavelet analysis with Morlet wavelet transform to determine the periods of fundamental mode and its first harmonic mode. The calculated period ratios have departures from its canonical value of 2. The density stratification and magnetic twist are two main factors which may cause these departures.

  6. A new high-resolution BOLAM-MOLOCH suite for the SIMM forecasting system: assessment over two HyMeX intense observation periods

    NASA Astrophysics Data System (ADS)

    Mariani, S.; Casaioli, M.; Coraci, E.; Malguzzi, P.

    2015-01-01

    High-resolution numerical models can be effective in monitoring and predicting natural hazards, especially when dealing with Mediterranean atmospheric and marine intense/severe events characterised by a wide range of interacting scales. The understanding of the key factors associated to these Mediterranean phenomena, and the usefulness of adopting high-resolution numerical models in their simulation, are among the aims of the international initiative HyMeX - HYdrological cycle in Mediterranean EXperiment. At the turn of 2013, two monitoring campaigns (SOPs - Special Observation Periods) were devoted to these issues. For this purpose, a new high-resolution BOlogna Limited Area Model-MOdello LOCale (BOLAM-MOLOCH) suite was implemented in the Institute for Environmental Protection and Research (ISPRA) hydro-meteo-marine forecasting system (SIMM - Sistema Idro-Meteo-Mare) as a possible alternative to the operational meteorological component based on the BOLAM model self-nested over two lower-resolution domains. The present paper provides an assessment of this new configuration of SIMM with respect to the operational one that was also used during the two SOPs. More in details, it investigates the forecast performance of these SIMM configurations during two of the Intense Observation Periods (IOPs) declared in the first SOP campaign. These IOPs were characterised by high precipitations and very intense and exceptional high waters over the northern Adriatic Sea (acqua alta). Concerning the meteorological component, the high-resolution BOLAM-MOLOCH forecasts are compared against the lower-resolution BOLAM forecasts over three areas - mostly corresponding to the Italian HyMeX hydrometeorological sites - using the rainfall observations collected in the HyMeX database. Three-month categorical scores are also calculated for the MOLOCH model. Despite the presence of a slight positive bias of the MOLOCH model, the results show that the precipitation forecast turns out to improve

  7. Open to Suggestion.

    ERIC Educational Resources Information Center

    Journal of Reading, 1987

    1987-01-01

    Offers (1) suggestions for improving college students' study skills; (2) a system for keeping track of parent, teacher, and community contacts; (3) suggestions for motivating students using tic tac toe; (4) suggestions for using etymology to improve word retention; (5) a word search grid; and (6) suggestions for using postcards in remedial reading…

  8. Origin of transient self-potential signals associated with very long period seismic pulses observed during the 2000 activity of Miyakejima volcano

    NASA Astrophysics Data System (ADS)

    Kuwano, O.; Nakatani, M.; Yoshida, S.; Uyeshima, M.

    2015-12-01

    Origin of the previously reported transient geoelectrical (self-potential, SP) signals in the Miyakejima 2000 activity, that repeatedly occurred concurrently with very long period (VLP) seismic pulses, was investigated. SP waveforms stacked across repeated VLP events showed a step-like rise followed by a gradual decay at all stations spread over the island of 8 km diameter. Within a realistic range of hydrological diffusivity, the short time constants of the SP signals cannot be explained by the electrokinetic effect caused by fluid flow within a limited volume, proposed earlier as a fluid injection hypothesis. On the other hand, poroelasticity predicts an island-wide distributed flow field to occur almost instantaneously upon VLP events due to the step of strain field imposed by the mechanical event. We propose that the observed SP signals resulted from the streaming current by this island-wide flow field. Our quantitative model, assuming a vertical tensile crack as a mechanical source, which has been suggested by preceding seismic studies, can explain the time constants and the amplitude of the SP signals (both spatial pattern and absolute amplitude), within a reasonable range of rock properties and the scalar moment of the mechanical source (VLP event). Location and attitude of the mechanical source were well constrained by grid search and are consistent with those estimated earlier from other types of data.

  9. Origin of transient self-potential signals associated with very long period seismic pulses observed during the 2000 activity of Miyakejima volcano

    NASA Astrophysics Data System (ADS)

    Kuwano, Osamu; Yoshida, Shingo; Nakatani, Masao; Uyeshima, Makoto

    2015-05-01

    Origin of the previously reported transient geoelectrical (self-potential, SP) signals in the Miyakejima 2000 activity, that repeatedly occurred concurrently with very long period (VLP) seismic pulses, was investigated. SP waveforms stacked across repeated VLP events showed a step-like rise followed by a gradual decay at all stations spread over the island of 8 km diameter. Within a realistic range of hydrological diffusivity, the short time constants of the SP signals cannot be explained by the electrokinetic effect caused by fluid flow within a limited volume, proposed earlier as a fluid injection hypothesis. On the other hand, poroelasticity predicts an island-wide distributed flow field to occur almost instantaneously upon VLP events due to the step of strain field imposed by the mechanical event. We propose that the observed SP signals resulted from the streaming current by this island-wide flow field. Our quantitative model, assuming a vertical tensile crack as a mechanical source, which has been suggested by preceding seismic studies, can explain the time constants and the amplitude of the SP signals (both spatial pattern and absolute amplitude), within a reasonable range of rock properties and the scalar moment of the mechanical source (VLP event). Location and attitude of the mechanical source were well constrained by grid search and are consistent with those estimated earlier from other types of data.

  10. Anomalous domain periodicity observed in ferroelectric PbTiO3 nanodots having 180° stripe domains

    PubMed Central

    Son, Jong Yeog; Song, Seungwoo; Lee, Jung-Hoon; Jang, Hyun Myung

    2016-01-01

    Nanometer-scale ferroelectric dots and tubes have received a great deal of attention owing to their potential applications to nonvolatile memories and multi-functional devices. As for the size effect of 180° stripe domains in ferroelectric thin films, there have been numerous reports on the thickness-dependent domain periodicity. All these studies have revealed that the domain periodicity (w) of 180° stripe domains scales with the film thickness (d) according to the classical Landau-Lifshitz-Kittel (LLK) scaling law (w ∝ d1/2) down to the thickness of ~2 nm. In the case of PbTiO3 nanodots, however, we obtained a striking correlation that for the thickness less than a certain critical value, dc (~35 nm), the domain width even increases with decreasing thickness of the nanodot, which surprisingly indicates a negative value in the LLK scaling-law exponent. On the basis of theoretical considerations of dc, we attributed this anomalous domain periodicity to the finite lateral-size effect of a ferroelectric nanodot with an additional effect possibly coming from the existence of a thin non-ferroelectric surface layer. PMID:27226162