WorldWideScience

Sample records for extremely short periods

  1. Estimating return periods of extreme values from relatively short time series of winds

    Science.gov (United States)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  2. HATS-18 b: An Extreme Short--Period Massive Transiting Planet Spinning Up Its Star

    CERN Document Server

    Penev, Dr Kaloyan M; Bakos, Dr Gaspar A; Ciceri, Ms Simona; Brahm, Dr Rafael; Bayliss, Dr Daniel; Bento, Joao; Jord'an, Andr'es; Csubry, Mr Zoltan; Bhatti, W; de Val-Borro, Miguel; Espinoza, Mr Néstor; Zhou, Dr George; Mancini, Dr Luigi; Rabus, Dr Markus; Suc, Vincent; Henning, Thomas; Schmidt, Prof Brian P; Noyes, Dr Robert W; L'az'ar, J; Papp, Istvan; S'ari, P

    2016-01-01

    We report the discovery by the HATSouth network of HATS-18 b: a 1.980 +/- 0.077 Mj, 1.337 +0.102 -0.049 Rj planet in a 0.8378 day orbit, around a solar analog star (mass 1.037 +/- 0.047 Msun, and radius 1.020 +0.057 -0.031 Rsun) with V=14.067 +/- 0.040 mag. The high planet mass, combined with its short orbital period, implies strong tidal coupling between the planetary orbit and the star. In fact, given its inferred age, HATS-18 shows evidence of significant tidal spin up, which together with WASP-19 (a very similar system) allows us to constrain the tidal quality factor for Sun-like stars to be in the range 6.5 <= lg(Q*/k_2) <= 7 even after allowing for extremely pessimistic model uncertainties. In addition, the HATS-18 system is among the best systems (and often the best system) for testing a multitude of star--planet interactions, be they gravitational, magnetic or radiative, as well as planet formation and migration theories.

  3. HATS-18b: An Extreme Short-period Massive Transiting Planet Spinning Up Its Star

    Science.gov (United States)

    Penev, K.; Hartman, J. D.; Bakos, G. Á.; Ciceri, S.; Brahm, R.; Bayliss, D.; Bento, J.; Jordán, A.; Csubry, Z.; Bhatti, W.; de Val-Borro, M.; Espinoza, N.; Zhou, G.; Mancini, L.; Rabus, M.; Suc, V.; Henning, T.; Schmidt, B.; Noyes, R. W.; Lázár, J.; Papp, I.; Sári, P.

    2016-11-01

    We report the discovery by the HATSouth network of HATS-18b: a 1.980+/- 0.077 {M}{{J}}, {1.337}-0.049+0.102 {R}{{J}} planet in a 0.8378 day orbit, around a solar analog star (mass 1.037+/- 0.047 {M}⊙ and radius {1.020}-0.031+0.057 {R}⊙ ) with V=14.067+/- 0.040 mag. The high planet mass, combined with its short orbital period, implies strong tidal coupling between the planetary orbit and the star. In fact, given its inferred age, HATS-18 shows evidence of significant tidal spin up, which together with WASP-19 (a very similar system) allows us to constrain the tidal quality factor for Sun-like stars to be in the range of 6.5≲ {{log}}10({Q}* /{k}2)≲ 7 even after allowing for extremely pessimistic model uncertainties. In addition, the HATS-18 system is among the best systems (and often the best system) for testing a multitude of star-planet interactions, be they gravitational, magnetic, or radiative, as well as planet formation and migration theories. The HATSouth network is operated by a collaboration consisting of Princeton University (PU), the Max Planck Institute für Astronomie (MPIA), the Australian National University (ANU), and the Pontificia Universidad Católica de Chile (PUC). The station at Las Campanas Observatory (LCO) of the Carnegie Institute is operated by PU in conjunction with PUC, the station at the High Energy Spectroscopic Survey (H.E.S.S.) site is operated in conjunction with MPIA, and the station at Siding Spring Observatory (SSO) is operated jointly with ANU. This paper includes data gathered with the MPG 2.2 m telescope at the ESO Observatory in La Silla. This paper uses observations obtained with facilities of the Las Cumbres Observatory Global Telescope.

  4. Extremal periodic wave profiles

    Directory of Open Access Journals (Sweden)

    E. van Groesen

    2007-01-01

    Full Text Available As a contribution to deterministic investigations into extreme fluid surface waves, in this paper wave profiles of prescribed period that have maximal crest height will be investigated. As constraints the values of the momentum and energy integrals are used in a simplified description with the KdV model. The result is that at the boundary of the feasible region in the momentum-energy plane, the only possible profiles are the well known cnoidal wave profiles. Inside the feasible region the extremal profiles of maximal crest height are "cornered" cnoidal profiles: cnoidal profiles of larger period, cut-off and periodically continued with the prescribed period so that at the maximal crest height a corner results.

  5. Production of well-matured compost from night-soil sludge by an extremely short period of thermophilic composting.

    Science.gov (United States)

    Nakasaki, Kiyohiko; Ohtaki, Akihito; Takemoto, Minoru; Fujiwara, Shunrokuro

    2011-03-01

    The effect of various operational conditions on the decomposition of organic material during the composting of night-soil treatment sludge was quantitatively examined. The optimum composting conditions were found to be a temperature of ca. 60°C and an initial pH value of 8. Rapid decomposition of organic matter ceased by the sixth day of composting under these optimum conditions, and the final value of the cumulative emission of carbon (E(C)), which represents the degree of organic matter decomposition, was less than 40%, indicating that the sludge contained only a small amount of easily degradable organic material. A plant growth assay using Komatsuna (Brassica campestris L. var. rapiferafroug) in a 1/5000a standard cultivation pot was then conducted for the compost at various degrees of organic matter decomposition: the raw composting material, the final compost obtained on day 6, and the 2 intermediate compost products (i.e., E(C)=10% and 20%). It was found that the larger the E(C), the greater the yield of Komatsuna growth. It was also found that 6 days of composting is sufficient to promote Komatsuna growth at the standard loading level, which is equivalent to a 1.5 g N/pot, since the promotion effect was as high as that obtained using chemical fertilizer. It can therefore be concluded that well-matured compost could be obtained in a short period of time (i.e., as early as 6 days), when night-soil sludge is composted under optimum conditions.

  6. Photometric and H-alpha studies of two extreme mass-ratio short period contact binaries in the direction of open cluster Praesepe

    CERN Document Server

    Rukmini, J

    2016-01-01

    We present the high precession photometric studies in V band and spectroscopic studies centered around H-alpha line for two extreme mass-ratio short period contact binaries ASAS J082243+1927.0 (V1) and ASAS J085710+1856.8 (V2). The variables in study are in the direction of open cluster Praesepe. From the light curve analysis V1 was found to be a low mass-ratio over-contact binary of A-type, with a mass ratio q 0.121 and fill-out factor f 72%, and V2 was found to be a low mass contact binary of W-type, with a mass-ratio q 1.29 and fill-out factor f 11% (marginal contact). The study of H-alpha absorption line profile of both the variables shows variation in equivalent widths (EWs) with orbital phases. The mean EWs of the H-alpha line were obtained as 1.6+or-0.13 A and 1.18+or-0.12 A for V1 and V2 respectively. The variation of H-alpha absorption with respect to phase is explained to be due to chromospheric activity in V1, as evident from the O Connell effect and that due to chromospheric flares, winds or photo...

  7. Semiclassical quantization with short periodic orbits

    CERN Document Server

    Vergini, E G; Vergini, Eduardo G.; Carlo, Gabriel

    2000-01-01

    We apply a recently developed semiclassical theory of short peridic orbits to the stadium billiard. We give explicit expresions for the resonances of periodic orbits and for the application of the semiclassical Hamiltonian operator to them. Then, by using the 3 shortest periodic orbits and 2 more living in the bouncing ball region, we obtain the first 25 odd-odd eigenfunctions with surprising accuracy.

  8. Short Periodicities in Latitudinal Variation of Sunspots

    Science.gov (United States)

    Kim, Bang-Yeop; Chang, Heon-Young

    2011-06-01

    The latitudinal variation of sunspots appearing during the period from 1874 to 2009 has been studied in terms of centerof- latitude (COL). The butterfly diagram has been used to study the evolution of the magnetic field and the dynamics at the bottom of the solar convection zone. Short-term periodicities have been of particular interest, in that they are somehow related to the structure and dynamics of the solar interior. We thus have focused our investigation on shortterm periodicities. We first calculated COL by averaging the latitude of sunspots with the weight function in area. Then, we analyzed the time series of COL using the wavelet transform technique. We found that a periodicity of ~5 years is the most dominant feature in the time series of COL, with the exception of the ~11 year solar cycle itself. This periodicity can be easily understood by considering small humps between the minima in the area-weighted butterfly diagram. However, we find that periodicities of ~1.3 (0.064), ~1.5 (0.056), or ~1.8 (0.046) years ( 1/ month ), which have been previously suggested as evidence of links between the changing structure of the sunspot zone and the tachocline rotation rate oscillations, are insignificant and inconsistent. We therefore conclude that the only existing short-term periodicity is of ~5 years, and that periodicities of ~1.3, ~1.5, or ~1.8 years are likely to be artifacts due to random noise of small sunspots.

  9. Application of short-data methods on extreme surge levels

    Science.gov (United States)

    Feng, X.

    2014-12-01

    Tropical cyclone-induced storm surges are among the most destructive natural hazards that impact the United States. Unfortunately for academic research, the available time series for extreme surge analysis are very short. The limited data introduces uncertainty and affects the accuracy of statistical analyses of extreme surge levels. This study deals with techniques applicable to data sets less than 20 years, including simulation modelling and methods based on the parameters of the parent distribution. The verified water levels from water gauges spread along the Southwest and Southeast Florida Coast, as well as the Florida Keys, are used in this study. Methods to calculate extreme storm surges are described and reviewed, including 'classical' methods based on the generalized extreme value (GEV) distribution and the generalized Pareto distribution (GPD), and approaches designed specifically to deal with short data sets. Incorporating global-warming influence, the statistical analysis reveals enhanced extreme surge magnitudes and frequencies during warm years, while reduced levels of extreme surge activity are observed in the same study domain during cold years. Furthermore, a non-stationary GEV distribution is applied to predict the extreme surge levels with warming sea surface temperatures. The non-stationary GEV distribution indicates that with 1 Celsius degree warming in sea surface temperature from the baseline climate, the 100-year return surge level in Southwest and Southeast Florida will increase by up to 40 centimeters. The considered statistical approaches for extreme surge estimation based on short data sets will be valuable to coastal stakeholders, including urban planners, emergency managers, and the hurricane and storm surge forecasting and warning system.

  10. Existence of extremal periodic solutions for quasilinear parabolic equations

    Directory of Open Access Journals (Sweden)

    Siegfried Carl

    1997-01-01

    bounded domain under periodic Dirichlet boundary conditions. Our main goal is to prove the existence of extremal solutions among all solutions lying in a sector formed by appropriately defined upper and lower solutions. The main tools used in the proof of our result are recently obtained abstract results on nonlinear evolution equations, comparison and truncation techniques and suitably constructed special testfunction.

  11. The Short Rotation Period of Nereid

    CERN Document Server

    Grav, T; Kavelaars, J J

    2003-01-01

    We determine the period, p = 11.52 \\pm 0.14 h, and a light curve peak-to-peak amplitude, a = 0.029 \\pm 0.003 magnitudes, of the Neptunian irregular satellite Nereid. If the light curve variation is due to albedo variations across the surface, rather than solely to the shape of Nereid variations, the rotation period would be a factor of two shorter. In either case, such a rotation period and light curve amplitude, together with Nereid's orbital period, p=360.14 days, imply that Nereid is almost certainly in a regular rotation state, rather than the chaotic rotation state suggested by Schaefer and Schaefer (1988,2000) and Dobrovolskis (1995). Assuming that Nereid is perfectly spherical, the albedo variation is 3% across the observed surface. Assuming a uniform geometric albedo, the observed cross sectional area varies by 3%. We caution that the lightcurve found in this paper only sets limits on the combination of albedo and physical irregularity and that we cannot determine the orientation of Nereid's spin axis...

  12. 3382 Cassidy: A Short Period Asteroid

    Science.gov (United States)

    Risley, Ethan

    2013-04-01

    The asteroid 3382 Cassidy was observed from the Etscorn Campus Observatory (ECO, 2012) at New Mexico Institute of Mining and Technology in Socorro, NM, on nine nights over a span of 43 days in 2012 September-November. A bimodal synodic period of 4.254 ± 0.002 h and an amplitude of 0.15 ± 0.02 mag were obtained.

  13. Thyrotoxic periodic paralysis: a short clinical review

    Directory of Open Access Journals (Sweden)

    Rashmi Aggarwal

    2015-06-01

    Full Text Available Thyrotoxic Periodic Paralysis (TPP is a potentially lethal manifestation of hyperthyroidism which is characterized by hypokalemia and muscular weakness. It mainly affects Asian men in the age group of 20 to 40 years. Immediate supplementation with oral or intravenous potassium will help to not only abort the acute attack of paralysis but will also prevent serious and life threatening cardiac arrhythmias. Non selective beta blockers like propranolol can also be used to ameliorate and prevent subsequent paralytic attack. Acetazolamide has no role in the treatment of TPP. [Int J Res Med Sci 2015; 3(3.000: 539-542

  14. Thermal Tides in Short Period Exoplanets

    CERN Document Server

    Arras, Phil

    2009-01-01

    Time-dependent insolation in a planetary atmosphere induces a mass quadrupole upon which the stellar tidal acceleration can exert a force. This "thermal tide" force can give rise to secular torques on the planet and orbit as well as radial forces causing eccentricity evolution. We apply this idea to the close-in gas giant exoplanets ("hot Jupiters"). The response of radiative atmospheres is computed in a hydrostatic model which treats the insolation as a time-dependent heat source, and solves for thermal radiation using flux-limited diffusion. Fully nonlinear numerical simulations are compared to solutions of the linearized equations, as well as analytic approximations, all of which are in good agreement. We find generically that thermal tide density perturbations {\\it lead} the semi-diurnal forcing. As a result thermal tides can generate asynchronous spin and eccentricity. Our results are as follows: (1) Departure from synchronous spin is significant for hot Jupiters, and increases with orbital period. (2) O...

  15. Transitions between refrigeration regions in extremely short quantum cycles

    Science.gov (United States)

    Feldmann, Tova; Kosloff, Ronnie

    2016-05-01

    The relation between the geometry of refrigeration cycles and their performance is explored. The model studied is based on a coupled spin system. Small cycle times, termed sudden refrigerators, develop coherence and inner friction. We explore the interplay between coherence and energy of the working medium employing a family of sudden cycles with decreasing cycle times. At the point of maximum coherence the cycle changes geometry. This region of cycle times is characterized by a dissipative resonance where heat is dissipated both to the hot and cold baths. We rationalize the change of geometry of the cycle as a result of a half-integer quantization which maximizes coherence. From this point on, increasing or decreasing the cycle time, eventually leads to refrigeration cycles. The transition point between refrigerators and short circuit cycles is characterized by a transition from finite to singular dynamical temperature. Extremely short cycle times reach a universal limit where all cycles types are equivalent.

  16. Concussion Can Spur Short-Term Change in Women's Periods

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_167006.html Concussion Can Spur Short-Term Change in Women's Periods ... MONDAY, July 3, 2017 (HealthDay News) -- After a concussion, a young woman might notice that her next ...

  17. Projected changes to short- and long-duration precipitation extremes over the Canadian Prairie Provinces

    Science.gov (United States)

    Masud, M. B.; Khaliq, M. N.; Wheater, H. S.

    2017-09-01

    The effects of climate change on April-October short- and long-duration precipitation extremes over the Canadian Prairie Provinces were evaluated using a multi-Regional Climate Model (RCM) ensemble available through the North American Regional Climate Change Assessment Program. Simulations considered include those performed with six RCMs driven by the National Centre for Environmental Prediction (NCEP) reanalysis II product for the 1981-2000 period and those driven by four Atmosphere-Ocean General Circulation Models (AOGCMs) for the current 1971-2000 and future 2041-2070 periods (i.e. a total of 11 current-to-future period simulation pairs). A regional frequency analysis approach was used to develop 2-, 5-, 10-, 25-, and 50-year return values of precipitation extremes from NCEP and AOGCM-driven current and future period simulations that respectively were used to study the performance of RCMs and projected changes for selected return values at regional, grid-cell and local scales. Performance errors due to internal dynamics and physics of RCMs studied for the 1981-2000 period reveal considerable variation in the performance of the RCMs. However, the performance errors were found to be much smaller for RCM ensemble averages than for individual RCMs. Projected changes in future climate to selected regional return values of short-duration (e.g. 15- and 30-min) precipitation extremes and for longer return periods (e.g. 50-year) were found to be mostly larger than those to the longer duration (e.g. 24- and 48-h) extremes and short return periods (e.g. 2-year). Overall, projected changes in precipitation extremes were larger for southeastern regions followed by southern and northern regions and smaller for southwestern and western regions of the study area. The changes to return values were also found to be statistically significant for the majority of the RCM-AOGCM simulation pairs. These projections might be useful as a key input for the future planning of urban

  18. Projected changes to short- and long-duration precipitation extremes over the Canadian Prairie Provinces

    Science.gov (United States)

    Masud, M. B.; Khaliq, M. N.; Wheater, H. S.

    2016-10-01

    The effects of climate change on April-October short- and long-duration precipitation extremes over the Canadian Prairie Provinces were evaluated using a multi-Regional Climate Model (RCM) ensemble available through the North American Regional Climate Change Assessment Program. Simulations considered include those performed with six RCMs driven by the National Centre for Environmental Prediction (NCEP) reanalysis II product for the 1981-2000 period and those driven by four Atmosphere-Ocean General Circulation Models (AOGCMs) for the current 1971-2000 and future 2041-2070 periods (i.e. a total of 11 current-to-future period simulation pairs). A regional frequency analysis approach was used to develop 2-, 5-, 10-, 25-, and 50-year return values of precipitation extremes from NCEP and AOGCM-driven current and future period simulations that respectively were used to study the performance of RCMs and projected changes for selected return values at regional, grid-cell and local scales. Performance errors due to internal dynamics and physics of RCMs studied for the 1981-2000 period reveal considerable variation in the performance of the RCMs. However, the performance errors were found to be much smaller for RCM ensemble averages than for individual RCMs. Projected changes in future climate to selected regional return values of short-duration (e.g. 15- and 30-min) precipitation extremes and for longer return periods (e.g. 50-year) were found to be mostly larger than those to the longer duration (e.g. 24- and 48-h) extremes and short return periods (e.g. 2-year). Overall, projected changes in precipitation extremes were larger for southeastern regions followed by southern and northern regions and smaller for southwestern and western regions of the study area. The changes to return values were also found to be statistically significant for the majority of the RCM-AOGCM simulation pairs. These projections might be useful as a key input for the future planning of urban

  19. How Do Earth-Sized, Short-Period Planets Form?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    Matching theory to observation often requires creative detective work. In a new study, scientists have used a clever test to reveal clues about the birth of speedy, Earth-sized planets.Former Hot Jupiters?Artists impression of a hot Jupiter with an evaporating atmosphere. [NASA/Ames/JPL-Caltech]Among the many different types of exoplanets weve observed, one unusual category is that of ultra-short-period planets. These roughly Earth-sized planets speed around their host stars at incredible rates, with periods of less than a day.How do planets in this odd category form? One popular theory is that they were previously hot Jupiters, especially massive gas giants orbiting very close to their host stars. The close orbit caused the planets atmospheres to be stripped away, leaving behind only their dense cores.In a new study, a team of astronomers led by Joshua Winn (Princeton University) has found a clever way to test this theory.Planetary radius vs. orbital period for the authors three statistical samples (colored markers) and the broader sample of stars in the California Kepler Survey. [Winn et al. 2017]Testing MetallicitiesStars hosting hot Jupiters have an interesting quirk: they typically have metallicities that are significantly higher than an average planet-hosting star. It is speculated that this is because planets are born from the same materials as their host stars, and hot Jupiters require the presence of more metals to be able to form.Regardless of the cause of this trend, if ultra-short-period planets are in fact the solid cores of former hot Jupiters, then the two categories of planets should have hosts with the same metallicity distributions. The ultra-short-period-planet hosts should therefore also be weighted to higher metallicities than average planet-hosting stars.To test this, the authors make spectroscopic measurements and gather data for a sample of stellar hosts split into three categories:64 ultra-short-period planets (orbital period shorter than a

  20. Short period eclipsing binary candidates identified using SuperWASP

    CERN Document Server

    Norton, A J; Evans, T; West, R G; Wheatley, P J; Anderson, D R; Barros, S C C; Butters, O W; Cameron, A Collier; Christian, D J; Enoch, B; Faedi, F; Haswell, C A; Hellier, C; Holmes, S; Horne, K D; Lister, T A; Maxted, P F L; Parley, N; Pollacco, D; Simpson, E K; Skillen, I; Smalley, B; Southworth, J; Street, R A

    2011-01-01

    We present light curves and periods of 53 candidates for short period eclipsing binary stars identified by SuperWASP. These include 48 newly identified objects with periods <2x10^4 seconds (~0.23d), as well as the shortest period binary known with main sequence components (GSC2314-0530 = 1SWASP J022050.85+332047.6) and four other previously known W UMa stars (although the previously reported periods for two of these four are shown to be incorrect). The period distribution of main sequence contact binaries shows a sharp cut-off at a lower limit of around 0.22d, but until now, very few systems were known close to this limit. These new candidates will therefore be important for understanding the evolution of low mass stars and to allow investigation of the cause of the period cut-off.

  1. Ship motion extreme short time prediction of ship pitch based on diagonal recurrent neural network

    Institute of Scientific and Technical Information of China (English)

    SHEN Yan; XIE Mei-ping

    2005-01-01

    A DRNN (diagonal recurrent neural network) and its RPE (recurrent prediction error) learning algorithm are proposed in this paper .Using of the simple structure of DRNN can reduce the capacity of calculation. The principle of RPE learning algorithm is to adjust weights along the direction of Gauss-Newton. Meanwhile, it is unnecessary to calculate the second local derivative and the inverse matrixes, whose unbiasedness is proved. With application to the extremely short time prediction of large ship pitch, satisfactory results are obtained. Prediction effect of this algorithm is compared with that of auto-regression and periodical diagram method, and comparison results show that the proposed algorithm is feasible.

  2. Ultra-short period binaries from the Catalina Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A. A.; Donalek, C.; Williams, R. [California Institute of Technology, 1200 East California Boulevard, CA 91225 (United States); García-Álvarez, D. [Instituto de Astrofísica de Canarias, Avenida Vía Láctea, 38205 La Laguna, Tenerife (Spain); Catelan, M.; Torrealba, G. [Pontificia Universidad Católica de Chile, Departamento de Astronomía y Astrofísica, Facultad de Física, Av. Vicuña Mackena 4860, 782-0436 Macul, Santiago (Chile); Prieto, J. L. [Department of Astronomy, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Abraham, S. [St. Thomas College, Kozhencheri 689641 (India); Larson, S.; Christensen, E. [Department of Planetary Sciences, The University of Arizona, Lunar and Planetary Laboratory, 1629 East University Boulevard, Tucson, AZ 85721 (United States)

    2014-08-01

    We investigate the properties of 367 ultra-short period binary candidates selected from 31,000 sources recently identified from Catalina Surveys data. Based on light curve morphology, along with WISE, Sloan Digital Sky Survey, and GALEX multi-color photometry, we identify two distinct groups of binaries with periods below the 0.22 day contact binary minimum. In contrast to most recent work, we spectroscopically confirm the existence of M dwarf+M dwarf contact binary systems. By measuring the radial velocity variations for five of the shortest-period systems, we find examples of rare cool white dwarf (WD)+M dwarf binaries. Only a few such systems are currently known. Unlike warmer WD systems, their UV flux and optical colors and spectra are dominated by the M-dwarf companion. We contrast our discoveries with previous photometrically selected ultra-short period contact binary candidates and highlight the ongoing need for confirmation using spectra and associated radial velocity measurements. Overall, our analysis increases the number of ultra-short period contact binary candidates by more than an order of magnitude.

  3. Autocovariance prediction of short period Earth rotation parameters.

    Science.gov (United States)

    Kosek, W.

    The autocovariance prediction of equidistant model and Earth Rotation Parameters (ERP) time series are presented. It enables computation of a forecast without any a priori information. It has been applied to short period polar motion and Length of Day (LOD) time series. The differences between the predicted short-period polar motion and LOD data computed for the 7th, 14th and 21st day in the future for different starting prediction epochs point out on irregular variations in Earth rotation. Similar computations were made using the autoregressive prediction method. The irregular (unpredictable) variations computed by the autoregressive prediction are very similar to those computed by the autocovariance prediction. The frequency and time-frequency analysis of these irregular variations shows that they affect oscillations with different periods from about 20 to ≡130 days and in different epochs.

  4. Extremal projectors for contragredient Lie (super)symmetries (short review)

    CERN Document Server

    Tolstoy, V N

    2010-01-01

    A brief review of the extremal projectors for contragredient Lie (super)symmetries (finite-dimensional simple Lie algebras, basic classical Lie superalgebras, infinite-dimensional affine Kac-Moody algebras and superalgebras, as well as their quantum $q$-analogs) is given. Some bibliographic comments on the applications of extremal projectors are presented.

  5. Crystalline Undulator with a Small Amplitude and a Short Period

    CERN Document Server

    Kostyuk, Andriy

    2012-01-01

    The crystalline undulator is a single crystal with periodically bent crystallographic planes. If ultrarelativistic charged particles channel through such a crystal, they emit hard radiation of undulator type. A crystalline undulator with a bending amplitude smaller than the distance between the bent planes and a bending period shorter than the period of channeling oscillations is proposed. Heretofore, it was believed that such range of the bending parameters was unsuitable for a crystalline undulator. This point of view is refuted. In fact, the undulator with a small amplitude and a short period is far superior to what was proposed previously. It requires much lower beam energy for production of photons of the same frequency. Such an undulator allows for a larger effective number of undulator periods. It is predicted to emit intense undulator radiation with a narrow spectral distribution and lower and softer background.

  6. Semiclassical Theory of Short Periodic Orbits in Quantum Chaos

    CERN Document Server

    Vergini, E G

    2000-01-01

    We have developed a semiclassical theory of short periodic orbits to obtain all quantum information of a bounded chaotic Hamiltonian system. If T_1 is the period of the shortest periodic orbit, T_2 the period of the next one and so on, the number N_p.o. of periodic orbits required in the calculation is such that T_1+...+T_N_{p.o} is approximately T_H, with T_H the Heisenberg time. As a result N_p.o \\simeq h T_{H}/\\ln (h T_{H}), where h is the topological entropy. For methods related to the trace formula N_{p.o} \\simeq \\exp(h T_{H})/ (h T_{H}).

  7. Tidal Decay and Disruption of Short-Period Gaseous Exoplanets

    CERN Document Server

    Jackson, Brian; Peacock, Sarah; Arras, Phil; Penev, Kaloyan

    2016-01-01

    Many gaseous exoplanets in short-period orbits are on the verge or are in the process of tidal disruption. Moreover, orbital stability analysis shows tides can drive many hot Jupiters to spiral toward their host stars. Thus, the coupled processes of orbital evolution and tidal disruption likely shape the observed distribution of close-in exoplanets and may even be responsible for producing some of the short-period rocky planets. However, the exact outcome for a disrupting planet depends on its internal response to mass loss, and the accompanying orbital evolution can act to enhance or inhibit the disruption process. In this study, we apply the fully-featured and robust Modules for Experiments in Stellar Astrophysics (MESA) suite to model Roche-lobe overflow (RLO) of short-period gaseous planets. We show that, although the detailed evolution may depend on several properties of the planetary system, it is largely determined by the core mass of the disrupting gas giant. In particular, we find that the orbital ex...

  8. Regional trends in short-duration precipitation extremes: a flexible multivariate monotone quantile regression approach

    Science.gov (United States)

    Cannon, Alex

    2017-04-01

    Estimating historical trends in short-duration rainfall extremes at regional and local scales is challenging due to low signal-to-noise ratios and the limited availability of homogenized observational data. In addition to being of scientific interest, trends in rainfall extremes are of practical importance, as their presence calls into question the stationarity assumptions that underpin traditional engineering and infrastructure design practice. Even with these fundamental challenges, increasingly complex questions are being asked about time series of extremes. For instance, users may not only want to know whether or not rainfall extremes have changed over time, they may also want information on the modulation of trends by large-scale climate modes or on the nonstationarity of trends (e.g., identifying hiatus periods or periods of accelerating positive trends). Efforts have thus been devoted to the development and application of more robust and powerful statistical estimators for regional and local scale trends. While a standard nonparametric method like the regional Mann-Kendall test, which tests for the presence of monotonic trends (i.e., strictly non-decreasing or non-increasing changes), makes fewer assumptions than parametric methods and pools information from stations within a region, it is not designed to visualize detected trends, include information from covariates, or answer questions about the rate of change in trends. As a remedy, monotone quantile regression (MQR) has been developed as a nonparametric alternative that can be used to estimate a common monotonic trend in extremes at multiple stations. Quantile regression makes efficient use of data by directly estimating conditional quantiles based on information from all rainfall data in a region, i.e., without having to precompute the sample quantiles. The MQR method is also flexible and can be used to visualize and analyze the nonlinearity of the detected trend. However, it is fundamentally a

  9. Challenges estimating the return period of extreme floods for reinsurance applications

    Science.gov (United States)

    Raven, Emma; Busby, Kathryn; Liu, Ye

    2013-04-01

    Mapping and modelling extreme natural events is fundamental within the insurance and reinsurance industry for assessing risk. For example, insurers might use a 1 in 100-year flood hazard map to set the annual premium of a property, whilst a reinsurer might assess the national scale loss associated with the 1 in 200-year return period for capital and regulatory requirements. Using examples from a range of international flood projects, we focus on exploring how to define what the n-year flood looks like for predictive uses in re/insurance applications, whilst considering challenges posed by short historical flow records and the spatial and temporal complexities of flood. First, we shall explore the use of extreme value theory (EVT) statistics for extrapolating data beyond the range of observations in a marginal analysis. In particular, we discuss how to estimate the return period of historical flood events and explore the impact that a range of statistical decisions have on these estimates. Decisions include: (1) selecting which distribution type to apply (e.g. generalised Pareto distribution (GPD) vs. generalised extreme value distribution (GEV)); (2) if former, the choice of the threshold above which the GPD is fitted to the data; and (3) the necessity to perform a cluster analysis to group flow peaks to temporally represent individual flood events. Second, we summarise a specialised multivariate extreme value model, which combines the marginal analysis above with dependence modelling to generate industry standard event sets containing thousands of simulated, equi-probable floods across a region/country. These events represent the typical range of anticipated flooding across a region and can be used to estimate the largest or most widespread events that are expected to occur. Finally, we summarise how a reinsurance catastrophe model combines the event set with detailed flood hazard maps to estimate the financial cost of floods; both the full event set and also

  10. Minimal model for short-time diffusion in periodic potentials.

    Science.gov (United States)

    Emary, Clive; Gernert, Robert; Klapp, Sabine H L

    2012-12-01

    We investigate the dynamics of a single, overdamped colloidal particle, which is driven by a constant force through a one-dimensional periodic potential. We focus on systems with large barrier heights where the lowest-order cumulants of the density field, that is, average position and the mean-squared displacement, show nontrivial (nondiffusive) short-time behavior characterized by the appearance of plateaus. We demonstrate that this "cage-like" dynamics can be well described by a discretized master equation model involving two states (related to two positions) within each potential valley. Nontrivial predictions of our approach include analytic expressions for the plateau heights and an estimate of the "de-caging time" obtained from the study of deviations from Gaussian behavior. The simplicity of our approach means that it offers a minimal model to describe the short-time behavior of systems with hindered dynamics.

  11. Theory of short periodic orbits for partially open quantum maps.

    Science.gov (United States)

    Carlo, Gabriel G; Benito, R M; Borondo, F

    2016-07-01

    We extend the semiclassical theory of short periodic orbits [M. Novaes et al., Phys. Rev. E 80, 035202(R) (2009)PLEEE81539-375510.1103/PhysRevE.80.035202] to partially open quantum maps, which correspond to classical maps where the trajectories are partially bounced back due to a finite reflectivity R. These maps are representative of a class that has many experimental applications. The open scar functions are conveniently redefined, providing a suitable tool for the investigation of this kind of system. Our theory is applied to the paradigmatic partially open tribaker map. We find that the set of periodic orbits that belongs to the classical repeller of the open map (R=0) is able to support the set of long-lived resonances of the partially open quantum map in a perturbative regime. By including the most relevant trajectories outside of this set, the validity of the approximation is extended to a broad range of R values. Finally, we identify the details of the transition from qualitatively open to qualitatively closed behavior, providing an explanation in terms of short periodic orbits.

  12. Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short-period and Ultra-short-period Planets

    Science.gov (United States)

    Lee, Eve J.; Chiang, Eugene

    2017-06-01

    Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to ˜10 days, but dwindle in number at shorter periods. Both the break at ˜10 days and the slope of the occurrence rate down to ˜1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at corotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks—as might be expected if planets formed in situ—rather than piled up near disk edges, as would be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short (starting point for understanding why the sub-Neptune population drops at ˜10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at ˜1 day instead of ˜10 days because A stars rotate faster than stars with lower masses (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).

  13. Short-period stellar activity cycles with Kepler photometry

    CERN Document Server

    Arkhypov, Oleksiy V; Lammer, Helmut; Güdel, Manuel; Lüftinger, Theresa; Johnstone, Colin P

    2015-01-01

    We study the short-periodic component of stellar activity with a cycle periods Pcyc up to 1000 days using the Kepler mission photometry of fast-rotating (rotational periods from 1 to 4 days) stars with spectra of M4V to F3V. Applying the originally developed two non-spectral methods, we measured the effective period of stellar cycles in 462 objects. The obtained results are in accordance with previous measurements by Vida et al. (2014), do not seem to result from a beating effect. The performed measurements of Pcyc cluster in a specific branch which covers the previously unstudied region in the Saar-Brandenburg (1999) diagram, and connects the branch of inactive stars with the area populated by super-active objects. It is shown that the formation of the discovered branch is due to the alpha-quenching effect, which saturates the magnetic dynamo and decreases the cycle periods with the increase of inverted Rossby number. This finding is important in the context of the discussion on catastrophic quenching and ot...

  14. Crystalline undulator with a small amplitude and a short period.

    Science.gov (United States)

    Kostyuk, Andriy

    2013-03-15

    The crystalline undulator is a single crystal with periodically bent crystallographic planes. If ultrarelativistic charged particles channel through such a crystal, they emit hard radiation of undulator type. A crystalline undulator with a bending amplitude smaller than the distance between the bent planes and a bending period shorter than the period of channeling oscillations is proposed. Heretofore, it was believed that such a range of bending parameters was unsuitable for a crystalline undulator. This point of view is refuted. In fact, the undulator with a small amplitude and a short period is far superior to what was proposed previously. It requires much lower beam energy for production of photons of the same frequency. Such an undulator allows for a larger effective number of undulator periods. It is predicted to emit intense undulator radiation in the forward direction with a narrow spectral distribution and a lower and softer background. The undulator effect is seen for both positron and electron beams. Using positrons is, however, preferable because they enable one to obtain higher intensity of the undulator radiation with lower background.

  15. Short Wave Amplification and Extreme Runup by the 2011 Tohoku Tsunami

    Science.gov (United States)

    Shimozono, Takenori; Cui, Haiyang; Pietrzak, Julie D.; Fritz, Hermann M.; Okayasu, Akio; Hooper, Andrew J.

    2014-12-01

    Watermarks found during the post-event surveys of the 2011 Tohoku tsunami confirmed extreme runup heights at several locations along the central to northern part of the Sanriku coast, Japan. We measured the maximum height of nearly 40 m above mean sea level at a narrow coastal valley of the Aneyoshi district. Wave records by offshore GPS-buoys suggest that the remarkably high runup was associated with a leading, impulsive crest of the tsunami amplified by local bathymetry and topography. In order to elucidate the underlying amplification mechanism, we apply a numerical model to reproduce the measured distribution of tsunami heights along the target coastline. A series of numerical tests under different boundary conditions suggests that a spectral component with a dominant period of 4-5 min in the leading wave play a key role in generating the extreme runup. Further analyses focusing on the Aneyoshi district confirm that the short wavelength component undergoes critical amplification in a narrow inlet. Our findings highlight the importance of resolving offshore waveforms as well as local bathymetry and topography when simulating extreme runup events.

  16. Planetary Trojans - the main source of short period comets?

    CERN Document Server

    Horner, Jonathan

    2010-01-01

    We present a short review of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primari...

  17. Rotational mixing in massive binaries: detached short-period systems

    CERN Document Server

    de Mink, S E; Langer, N; Pols, O R; Brott, I; Yoon, S -Ch

    2009-01-01

    Models of rotating single stars can successfully account for a wide variety of observed stellar phenomena, such as the surface enhancements of N and He. However, recent observations have questioned the idea that rotational mixing is the main process responsible for the surface enhancements, emphasizing the need for a strong and conclusive test. We investigate the consequences of rotational mixing for massive main-sequence stars in short-period binaries. In these systems the tides spin up the stars to rapid rotation. We use a state-of-the-art stellar evolution code including the effect of rotational mixing, tides, and magnetic fields. We discuss the surface abundances expected in massive close binaries (M1~20 solar masses) and we propose using such systems to test the concept of rotational mixing. As these short-period binaries often show eclipses, their parameters can be determined with high accuracy, allowing for a direct comparison with binary evolution models. In more massive close systems (M1~50 solar mas...

  18. Period decrease in three SuperWASP eclipsing binary candidates near the short-period limit

    CERN Document Server

    Lohr, M E; Kolb, U C; Anderson, D R; Faedi, F; West, R G

    2012-01-01

    SuperWASP light curves for 53 W UMa-type eclipsing binary (EB) candidates, identified in previous work as being close to the contact binary short-period limit, were studied for evidence of period change. The orbital periods of most of the stars were confirmed, and period decrease, significant at more than 5 sigma, was observed in three objects: 1SWASP J174310.98+432709.6 (-0.055 \\pm0.003 s/yr), 1SWASP J133105.91+121538.0 (-0.075 \\pm0.013 s/yr) and 1SWASP J234401.81-212229.1 (-0.313 \\pm0.019 s/yr). The magnitudes of the observed period changes cannot be explained by magnetic braking or gravitational radiation effects, and are most likely primarily due to unstable mass transfer from primary to secondary components, possibly accompanied by unstable mass and angular momentum loss from the systems. If these period decreases persist, the systems could merge on a relatively short timescale.

  19. Nonlinear propagation of vector extremely short pulses in a medium of symmetric and asymmetric molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sazonov, S. V., E-mail: sazonov.sergey@gmail.com [National Research Centre “Kurchatov Institute,” (Russian Federation); Ustinov, N. V., E-mail: n-ustinov@mail.ru [Moscow State University of Railways, Kaliningrad Branch (Russian Federation)

    2017-02-15

    The nonlinear propagation of extremely short electromagnetic pulses in a medium of symmetric and asymmetric molecules placed in static magnetic and electric fields is theoretically studied. Asymmetric molecules differ in that they have nonzero permanent dipole moments in stationary quantum states. A system of wave equations is derived for the ordinary and extraordinary components of pulses. It is shown that this system can be reduced in some cases to a system of coupled Ostrovsky equations and to the equation intagrable by the method for an inverse scattering transformation, including the vector version of the Ostrovsky–Vakhnenko equation. Different types of solutions of this system are considered. Only solutions representing the superposition of periodic solutions are single-valued, whereas soliton and breather solutions are multivalued.

  20. An analysis of the radiation field characteristics for extremity dose assessment during maintenance periods at nuclear power plants in Korea.

    Science.gov (United States)

    Kim, Hee Geun; Kong, Tae Young

    2012-12-01

    Workers who maintain the water chambers of steam generators during maintenance periods in nuclear power plants (NPPs) have a higher likelihood of high radiation exposure, even if they are exposed for a short period of time. In particular, it is expected that the hands of workers would receive the highest radiation exposure as a consequence of hand contact with radioactive materials. In this study, a characteristic analysis of inhomogeneous radiation fields for contact operations was conducted using thermoluminescent dosemeters for the whole body and extremities during maintenance periods at Korean NPPs. It was observed that inhomogeneous radiation fields for contact operations at NPPs were dominated by high-energy photons.

  1. High resolution x-ray investigation of periodically poled lithium tantalate crystals with short periodicity

    CERN Document Server

    Bazzan, Marco; Argiolas, Nicola; Busacca, Alessandro C; Oliveri, Roberto L; Stivala, Salvatore; Curcio, Luciano; Sanseverino, Stefano Riva; 10.1063/1.3264620

    2012-01-01

    Domain engineering technology in lithium tantalate is a well studied approach for nonlinear optical applications. However, for several cases of interest, the realization of short period structures (< 2 \\mu m) is required, which make their characterization difficult with standard techniques. In this work, we show that high resolution x-ray diffraction is a convenient approach for the characterization of such structures, allowing us to obtain in a nondestructive fashion information such as the average domain period, the domain wall inclination, and the overall structure quality.

  2. Periodization of Carbohydrate Intake: Short-Term Effect on Performance

    Science.gov (United States)

    Marquet, Laurie-Anne; Hausswirth, Christophe; Molle, Odeline; Hawley, John A.; Burke, Louise M.; Tiollier, Eve; Brisswalter, Jeanick

    2016-01-01

    Background: “Sleep-low” consists of a sequential periodization of carbohydrate (CHO) availability—low glycogen recovery after “train high” glycogen-depleting interval training, followed by an overnight-fast and light intensity training (“train low”) the following day. This strategy leads to an upregulation of several exercise-responsive signaling proteins, but the chronic effect on performance has received less attention. We investigated the effects of short-term exposure to this strategy on endurance performance. Methods: Following training familiarization, 11 trained cyclists were divided into two groups for a one-week intervention—one group implemented three cycles of periodized CHO intake to achieve the sleep-low strategy over six training sessions (SL, CHO intake: 6 g·kg−1·day−1), whereas the control group consumed an even distribution of CHO over the day (CON). Tests were a 2 h submaximal ride and a 20 km time trial. Results: SL improved their performance (mean: +3.2%; p < 0.05) compared to CON. The improvement was associated with a change in pacing strategy with higher power output during the second part of the test. No change in substrate utilization was observed after the training period for either group. Conclusion: Implementing the “sleep-low” strategy for one week improved performance by the same magnitude previously seen in a three-week intervention, without any significant changes in selected markers of metabolism. PMID:27897989

  3. Periodization of Carbohydrate Intake: Short-Term Effect on Performance

    Directory of Open Access Journals (Sweden)

    Laurie-Anne Marquet

    2016-11-01

    Full Text Available Background: “Sleep-low” consists of a sequential periodization of carbohydrate (CHO availability—low glycogen recovery after “train high” glycogen-depleting interval training, followed by an overnight-fast and light intensity training (“train low” the following day. This strategy leads to an upregulation of several exercise-responsive signaling proteins, but the chronic effect on performance has received less attention. We investigated the effects of short-term exposure to this strategy on endurance performance. Methods: Following training familiarization, 11 trained cyclists were divided into two groups for a one-week intervention—one group implemented three cycles of periodized CHO intake to achieve the sleep-low strategy over six training sessions (SL, CHO intake: 6 g·kg−1·day−1, whereas the control group consumed an even distribution of CHO over the day (CON. Tests were a 2 h submaximal ride and a 20 km time trial. Results: SL improved their performance (mean: +3.2%; p < 0.05 compared to CON. The improvement was associated with a change in pacing strategy with higher power output during the second part of the test. No change in substrate utilization was observed after the training period for either group. Conclusion: Implementing the “sleep-low” strategy for one week improved performance by the same magnitude previously seen in a three-week intervention, without any significant changes in selected markers of metabolism.

  4. SuPerPiG's Ultra-Short-Period Planets from K2 Campaigns 6 through 8

    Science.gov (United States)

    Jackson, Brian K.; Adams, Elisabeth R.; Endl, Michael

    2017-01-01

    The unexpected discoveries of hundreds of exoplanets very close to their host stars have challenged planet formation theories. The most extreme subset of these are the ultra-short-period planets, or USPs, with orbital periods of less than a day. These planets may provide unprecedented insights into planet formation and evolution and serve as sensitive probes for planet-star interactions and the stellar wind. Given their very short periods, such planets are particularly amenable to discovery by the Kepler, K2, and upcoming TESS missions and follow-up efforts. In this presentation, we will discuss our group’s ongoing search for ultra-short-period planets, the SuPerPiG effort. We will present our follow-up work and an updated list of candidates from our project, including a system with two small candidate planets, one with a period of about 13 hours and the other with a period of about 13 days.

  5. Periods of Excess Energy in Extreme Weather Events

    Directory of Open Access Journals (Sweden)

    Igor G. Zurbenko

    2013-01-01

    Full Text Available The reconstruction of periodic signals that are embedded in noise is a very important task in many applications. This already difficult task is even more complex when some observations are missed or some are presented irregularly in time. Kolmogorov-Zurbenko (KZ filtration, a well-developed method, offers a solution to this problem. One section of this paper provides examples of very precise reconstructions of multiple periodic signals covered with high level noise, noise levels that make those signals invisible within the original data. The ability to reconstruct signals from noisy data is applied to the numerical reconstruction of tidal waves in atmospheric pressure. The existence of such waves was proved by well-known naturalist Chapman, but due to the high synoptic fluctuation in atmospheric pressure he was unable to numerically reproduce the waves. Reconstruction of the atmospheric tidal waves reveals a potential intensification on wind speed during hurricanes, which could increase the danger imposed by hurricanes. Due to the periodic structure of the atmospheric tidal wave, it is predictable in time and space, which is important information for the prediction of excess force in developing hurricanes.

  6. Analysis of pressure buildup data following a short flow period

    Energy Technology Data Exchange (ETDEWEB)

    Raghavan, R.; Reynolds, A.C. Jr.; Meng, H.Z.

    1982-04-01

    Methods of analyzing buildup data following a short flow period are presented, discussed, and illustrated. A new type curve for uniform-flux and infinite-conductivity vertically fractured wells is presented. By matching buildup data with this new type curve, it is possible to determine the dimensionless flowing time before shut-in. A method for converting buildup data to equivalent drawdown data is discussed. This method can be used to combine buildup and drawdown data to obtain a longer band of data for type-curve matching. This method can be used for constant-rate production, constant-pressure production, and for the case where both pressure and rate vary during production. 17 refs.

  7. Desensitization to media violence over a short period of time.

    Science.gov (United States)

    Fanti, Kostas A; Vanman, Eric; Henrich, Christopher C; Avraamides, Marios N

    2009-01-01

    This study investigated the desensitization to violence over a short period of time. Participants watched nine violent movie scenes and nine comedy scenes, and reported whether they enjoyed the violent or comedy scenes and whether they felt sympathetic toward the victim of violence. Using latent growth modeling, analyses were carried out to investigate how participants responded to the different scenes across time. The findings of this study suggested that repeated exposure to media violence reduces the psychological impact of media violence in the short term, therefore desensitizing viewers to media violence. As a result, viewers tended to feel less sympathetic toward the victims of violence and actually enjoy more the violence portrayed in the media. Additionally, desensitization to media violence was better represented by a curvilinear pattern, whereas desensitization to comedy scenes was better represented by a linear pattern. Finally, trait aggression was not related to the pattern of change over time, although significant effects were found for initial reports of enjoyment and sympathy.

  8. Statistic analysis of annual total ozone extremes for the period 1964-1988

    Science.gov (United States)

    Krzyscin, Janusz W.

    1994-01-01

    Annual extremes of total column amount of ozone (in the period 1964-1988) from a network of 29 Dobson stations have been examined using the extreme value analysis. The extremes have been calculated as the highest deviation of daily mean total ozone from its long-term monthly mean, normalized by the monthly standard deviations. The extremes have been selected from the direct-Sun total ozone observations only. The extremes resulting from abrupt changes in ozone (day to day changes greater than 20 percent) have not been considered. The ordered extremes (maxima in ascending way, minima in descending way) have been fitted to one of three forms of the Fisher-Tippet extreme value distribution by the nonlinear least square method (Levenberg-Marguard method). We have found that the ordered extremes from a majority of Dobson stations lie close to Fisher-Tippet type III. The extreme value analysis of the composite annual extremes (combined from averages of the annual extremes selected at individual stations) has shown that the composite maxima are fitted by the Fisher-Tippet type III and the composite minima by the Fisher-Tippet type I. The difference between the Fisher-Tippet types of the composite extremes seems to be related to the ozone downward trend. Extreme value prognoses for the period 1964-2014 (derived from the data taken at: all analyzed stations, the North American, and the European stations) have revealed that the prognostic extremes are close to the largest annual extremes in the period 1964-1988 and there are only small regional differences in the prognoses.

  9. Planet Hunters: Assessing the Kepler Inventory of Short Period Planets

    CERN Document Server

    Schwamb, Megan E; Fischer, Debra A; Giguere, Matthew J; Lynn, Stuart; Smith, Arfon M; Brewer, John M; Parrish, Michael; Schawinski, Kevin; Simpson, Robert J

    2012-01-01

    We present the results from a search of data from the first 33.5 days of the Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters citizen science project. Planet Hunters enlists members of the general public to visually identify transits in the publicly released Kepler light curves via the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data set. We examine the abundance of \\geq 2 R\\oplus planets on short period (< 15 days) orbits based on Planet Hunters detections. We present these results along with an analysis of the detection efficiency of human classifiers to identify planetary transits including a comparison to the Kepler inventory of planet candidates. Although performance drops rapidly for smaller radii, \\geq 4 R\\oplus Planet Hunters \\geq 85% efficient at identifying transit signals for planets with periods less than 15 days for the Kepler sample of target stars. Our high efficiency rate for simulated transits along with recovery of the majority of Ke...

  10. The evolutionary state of short period magnetic white dwarf binaries

    CERN Document Server

    Breedt, E; Girven, J; Drake, A J; Copperwheat, C M; Parsons, S G; Marsh, T R

    2012-01-01

    We present phase-resolved spectroscopy of two new short period low accretion rate magnetic binaries, SDSSJ125044.42+154957.3 (Porb = 86 min) and SDSSJ151415.65+074446.5 (Porb = 89 min). Both systems were previously identified as magnetic white dwarfs from the Zeeman splitting of the Balmer absorption lines in their optical spectra. Their spectral energy distributions exhibit a large near-infrared excess, which we interpret as a combination of cyclotron emission and possibly a late type companion star. No absorption features from the companion are seen in our optical spectra. We derive the orbital periods from a narrow, variable H_alpha emission line which we show to originate on the companion star. The high radial velocity amplitude measured in both systems suggests a high orbital inclination, but we find no evidence for eclipses in our data. The two new systems resemble the polar EF Eri in its prolonged low state and also SDSSJ121209.31+013627.7, a known magnetic white dwarf plus possible brown dwarf binary,...

  11. Ultra Short Period Planets in K2 with companions: a double transiting system for EPIC 220674823

    CERN Document Server

    Adams, Elisabeth R; Endl, Michael; Cochran, William D; MacQueen, Phillip J; Duev, Dmitry A; Jensen-Clem, Rebecca; Salama, Maïssa; Ziegler, Carl; Baranec, Christoph; Kulkarni, Shrinivas; Law, Nicholas M; Riddle, Reed

    2016-01-01

    Two transiting planets have been identified orbiting K2 target EPIC 220674823. One object is an ultra-short-period planet with a period of just 0.57 days (13.7 hours), while the other has a period of 13.3 days. Both planets are small, with the former having a radius of R_p1=1.5 R_E and the latter R_p2=2.5 R_E. Follow-up observations, including radial velocity (with uncertainties of 110 m/s) and high-resolution adaptive optics imagery, show no signs of stellar companions. EPIC 220674823 is the twelfth confirmed or validated planetary system in which an ultra-short-period planet (i.e., having an orbital period less than one day) is accompanied by at least one additional planet, suggesting that such systems may be common and must be accounted for in models for the formation and evolution of such extreme systems.

  12. Second serial transverse enteroplasty procedure in an infant with extreme short bowel syndrome.

    Science.gov (United States)

    Oh, Jung-Tak; Koh, Hong; Chang, Eun Young; Chang, Hye Kyung; Han, Seok Joo

    2012-06-01

    The serial transverse enteroplasty (STEP) procedure is a novel technique to lengthen and taper the bowel in patients with short bowel syndrome. The advantages of STEP include not only technical ease and simplicity, but also the ability to repeat the procedure. Herein, we report a case of extreme short bowel syndrome that was successfully treated by the second STEP procedure. A 3-day old newborn girl underwent STEP because of jejunal atresia with the small bowel length of 15 cm, but her bowel elongation was not enough to escape from short bowel syndrome. At the age of 6 months, she underwent a second STEP procedure. The bowel lengthening by the second STEP made her tolerable to enteral feeding with body weight gain and rescued her from short bowel syndrome. This case showed that second STEP is very helpful in treatment of extreme short bowel syndrome.

  13. Magnetic activity and orbital period variation of the short-period eclipsing binary DV Psc

    Energy Technology Data Exchange (ETDEWEB)

    Pi, Qing-feng; Zhang, Li-Yun [College of Science/Department of Physics and NAOC-GZU-Sponsored Center for Astronomy Research, Guizhou University, Guiyang 550025 (China); Li, Zhong-mu [Institute for Astronomy and History of Science and Technology, Dali University, Dali 671003 (China); Zhang, Xi-liang, E-mail: liy_zhang@hotmail.com [Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011 (China)

    2014-03-01

    We present six new BVR{sub c}I{sub c} CCD light curves of a short-period RS CVn binary DV Psc obtained in 2010-2012. The light curve distortions change on both short and long timescales, which is explained by two starspots on the primary component. Moreover, five new flare events were detected and the flare ratio of DV Psc is about 0.082 flares per hour. There is a possible relation between the phases (longitude) of the flares and starspots for all of the available data of late-type binaries, which implies a correlation of the stellar activity of the spots and flares. The cyclic oscillation, with a period of 4.9 ± 0.4 yr, may result from the magnetic activity cycle, identified by the variability of Max. I-Max. II. Until now, there were no spectroscopic studies of chromospheric activity indicators of the H{sub β} and H{sub γ} lines for DV Psc. Our observations of these indicators show that DV Psc is active, with excess emissions. The updated O – C diagram with an observing time span of about 15 yr shows an upward parabola, which indicates a secular increase in the orbital period of DV Psc. The orbital period secularly increases at a rate of dP/dt = 2.0×10{sup –7} days yr{sup –1}, which might be explained by the angular momentum exchanges or mass transfer from the secondary to primary component.

  14. Evolution of extreme temperature events in short term climate projection for Iberian Peninsula.

    Science.gov (United States)

    Rodriguez, Alfredo; Tarquis, Ana M.; Sanchez, Enrique; Dosio, Alessandro; Ruiz-Ramos, Margarita

    2014-05-01

    Extreme events of maximum and minimum temperatures are a main hazard for agricultural production in Iberian Peninsula. For this purpose, in this study we analyze projections of their evolution that could be valid for the next decade, represented in this study by the 30-year period 2004-2034 (target period). For this purpose two kinds of data were used in this study: 1) observations from the station network of AEMET (Spanish National Meteorological Agency) for five Spanish locations, and 2) simulated data at a resolution of 50 ×50 km horizontal grid derived from the outputs of twelve Regional Climate Models (RCMs) taken from project ENSEMBLES (van der Linden and Mitchell, 2009), with a bias correction (Dosio and Paruolo, 2011; Dosio et al., 2012) regarding the observational dataset Spain02 (Herrera et al., 2012). To validate the simulated climate, the available period of observations was compared to a baseline period (1964-1994) of simulated climate for all locations. Then, to analyze the changes for the present/very next future, probability of extreme temperature events for 2004-2034 were compared to that of the baseline period. Although only minor changes are expected, small variations in variability may have a significant impact in crop performance. The objective of the work is to evaluate the utility of these short term projections for potential users, as for instance insurance companies. References Dosio A. and Paruolo P., 2011. Bias correction of the ENSEMBLES high-resolution climate change projections for use by impact models: Evaluation on the present climate. Journal of Geophysical Research, VOL. 116,D16106, doi:10.1029/2011JD015934 Dosio A., Paruolo P. and Rojas R., 2012. Bias correction of the ENSEMBLES high resolution climate change projections for use by impact models: Analysis of the climate change signal. Journal of Geophysical Research,Volume 117, D17, doi: 0.1029/2012JD017968 Herrera et. al. (2012) Development and Analysis of a 50 year high

  15. Peculiarities of the propagation of multidimensional extremely short optical pulses in germanene

    Science.gov (United States)

    Zhukov, Alexander V.; Bouffanais, Roland; Konobeeva, Natalia N.; Belonenko, Mikhail B.

    2016-09-01

    In this Letter, we study the propagation characteristics of both two-dimensional and three-dimensional extremely short optical pulses in germanene. A distinguishing feature of germanene-in comparison with other graphene-like structures-is the presence of a significant spin-orbit interaction. The account of this interaction has a significant impact on the evolution of extremely short pulses in such systems. Specifically, extremely short optical pulses, consisting of two electric field oscillations, cause the appearance of a tail associated with the excitation of nonlinear waves. Due to the large spin-orbit interaction in germanene, this tail behind the main pulse is much smaller in germanene-based samples as compared to graphene-based ones, thereby making germanene a preferred material for the stable propagation of pulses along the sample.

  16. Local Short Period Seismic Network at Villarrica Volcano

    Science.gov (United States)

    Mora-Stock, Cindy; Thorwart, Martin; Dzieran, Laura; Rabbel, Wolfgang

    2014-05-01

    Since its last eruption in 1984-85, the Villarrica volcano has been presenting both seismic and fumarolic activity, accompanied by an open vent and a refulgent lava lake. To study its activity, a local seismic network of 75 DSS-Cubes short-period stations was deployed at and around the volcano. During the first two weeks of March, 2012, 30 3-Component and 45 1-Component stations were installed in a 63 km x 55 km area, with spacing between stations of 1.5 km for stations inside the perimeter of the volcanic edifice, and 5 km outside this perimeter. In total, approximately 94 volcano tectonic (VT) events with clear P- and S- wave arrivals were located to the SSW, SSE and North of the Crater at an average depth of 3 km below sea level. At least 73 events classified as "hybrids" (HB) were observed, predominantly about 2 km above sea level near or at the conduit. They present emergent higher frequencies at the beginning of the signal, and sharp S-wave at the crater stations, but a strong scattering, lower frequency content, and elongated coda on the stations along the volcanic edifice, probably due to ash layers and heterogeneities at the edifice. A few long period events (LP) with frequencies between 2-4 Hz were observed during the two weeks. Three set of groups can be distinguished for the regional tectonic events: aftershocks on the southern end of the rupture of the Maule 2010 event, with S-P wave travel time difference of ca. 30 s or more; a second group with S-P travel time difference between 10 s and 20s; and the much closer group with S-P wave difference of 10 s or less. To determine the average velocity structure of the volcano, a cross-correlation analysis of the waves from a M6.1 event in Argentina and other regional events was performed. The model used was a cylindric model of 6.5 km radius inside the volcanic edifice, which gave a P-wave velocity of 3.6 km/s, and a region outside this radius with a velocity of 4.1 km. The network was divided into five zones

  17. Clinical case and short review of extreme short bowel syndrome: an update 21 years after

    Directory of Open Access Journals (Sweden)

    Pasquale Mansueto

    2016-03-01

    Full Text Available Short bowel syndrome refers to the malabsorptive state caused by loss of significant portions of the small intestine, whose clinical framework is characterized by malnutrition, diarrhea, dehydration, weight loss, and low-weight-related symptoms/signs. These clinical conditions seem to be related to the length of resection. Twenty-one years ago we reported the clinical case of an infant, who underwent a massive resection of the loops of the small intestine, of the cecum and of part of the ascending colon, due to intestinal malrotation with volvulus. The residual small intestine measured just 11 cm and consisted of the duodenum and a small part of jejunum, in the absence of the ileocecal valve, configuring the case of a ultra-short bowel syndrome. In this report, we update the case, reporting the patient succeeded to obtain a good weight gain and to conduct a quite normal lifestyle, despite the long-term consequences of such resection.

  18. The first orbital parameters and period variation of the short-period eclipsing binary AQ Boo

    Science.gov (United States)

    Wang, Shuai; Zhang, Liyun; Pi, Qingfeng; Han, Xianming L.; Zhang, Xiliang; Lu, Hongpeng; Wang, Daimei; Li, TongAn

    2016-10-01

    We obtained the first VRI CCD light curves of the short-period contact eclipsing binary AQ Boo, which was observed on March 22 and April 19 in 2014 at Xinglong station of National Astronomical Observatories, and on January 20, 21 and February 28 in 2015 at Kunming station of Yunnan Observatories of Chinese Academy of Sciences, China. Using our six newly obtained minima and the minima that other authors obtained previously, we revised the ephemeris of AQ Boo. By fitting the O-C (observed minus calculated) values of the minima, the orbital period of AQ Boo shows a decreasing tendency P˙ = - 1.47(0.17) ×10-7 days/year. We interpret the phenomenon by mass transfer from the secondary (more massive) component to the primary (less massive) one. By using the updated Wilson & Devinney program, we also derived the photometric orbital parameters of AQ Boo for the first time. We conclude that AQ Boo is a near contact binary with a low contact factor of 14.43%, and will become an over-contact system as the mass transfer continues.

  19. Crystalline Undulator with a Small Amplitude and a Short Period

    OpenAIRE

    Kostyuk, Andriy

    2012-01-01

    The crystalline undulator is a single crystal with periodically bent crystallographic planes. If ultrarelativistic charged particles channel through such a crystal, they emit hard radiation of undulator type. A crystalline undulator with a bending amplitude smaller than the distance between the bent planes and a bending period shorter than the period of channeling oscillations is proposed. Heretofore, it was believed that such a range of bending parameters was unsuitable for a crystalline und...

  20. 1SWASP J075102.16+342405.3: A deep overcontact binary system with a period under the short period cut-off

    Science.gov (United States)

    Jiang, Linqiao; Qian, Sheng-Bang; Zhang, Jia; Liu, Nianping

    2015-12-01

    New photometry of two different seasons for the extremely short period eclipsing binary 1SWASP J075102.16+342405.3 were performed. The two sets of derived light curves show a large difference in their shape, i.e., the 2013 light curves show big asymmetry, whereas the 2014 light curve is almost symmetric. All light curves were analysed using the 2013 version of the Wilson-Devinney (W-D) code. The obtained solutions show that 1SWASP J075102.16+342405.3 is of the A subtype W UMa contact system with an extremely high fill-out of f ≈ 96% and a high mass ratio of 0.70-0.78. Furthermore, a third light contributing to the total flux of the system was found. All these properties make the system a very special short-period source. The analysis of the 2013 light curves proved that the changes in the light curve shape are caused by magnetic activities. By means of all available times of minimum light, the variation of the orbital period was studied. It was found that the O - C diagram implies an increasing orbital period over a time span of eight years, which may be caused by the mass transfer from the less massive component to the more massive one; however, we are more inclined to say that it is only a part of a long period cyclic variation which can be explained by the light-travel time effect (LTTE) via the third body.

  1. Parent decision making for life support for extremely premature infants: from the prenatal through end-of-life period.

    Science.gov (United States)

    Moro, Teresa T; Kavanaugh, Karen; Savage, Teresa A; Reyes, Maria R; Kimura, Robert E; Bhat, Rama

    2011-01-01

    Most deaths of extremely premature infants occur in the perinatal period. Yet, little is known about how parents make life support decisions in such a short period of time. In the paper, how parents make life support decisions for extremely premature infants from the prenatal period through death from the perspectives of parents, nurses, and physicians is described. Five cases, comprised of five mothers, four neonatologists, three nurses, and one neonatal nurse practitioner, are drawn from a larger collective case study. Prenatal, postnatal and end-of-life interviews were conducted, and medical record data were obtained. In an analysis by two research team members, mothers were found to exhibit these characteristics: desire for and actual involvement in life support decisions, weighing pain, suffering and hope in decision making, and wanting everything done for their infants. All mothers received decision making help and support from partners and family, but relationships with providers were also important. Finally, external resources impacted parental decision making in several of the cases. By understanding what factors contribute to parents' decision making, providers may be better equipped to prepare and assist parents when making life support decisions for their extremely premature infants.

  2. Peculiarities of the propagation of multidimensional extremely short optical pulses in germanene

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, Alexander V., E-mail: alex_zhukov@sutd.edu.sg [Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore (Singapore); Bouffanais, Roland [Singapore University of Technology and Design, 8 Somapah Road, 487372 Singapore (Singapore); Konobeeva, Natalia N. [Volgograd State University, 400062 Volgograd (Russian Federation); Belonenko, Mikhail B. [Laboratory of Nanotechnology, Volgograd Institute of Business, 400048 Volgograd (Russian Federation); Volgograd State University, 400062 Volgograd (Russian Federation)

    2016-09-07

    Highlights: • Established dynamics of ultra-short pulses in germanene. • Studied balance between dispersive and nonlinear effects in germanene. • Spin–orbit interaction effect onto pulse propagation. - Abstract: In this Letter, we study the propagation characteristics of both two-dimensional and three-dimensional extremely short optical pulses in germanene. A distinguishing feature of germanene—in comparison with other graphene-like structures—is the presence of a significant spin–orbit interaction. The account of this interaction has a significant impact on the evolution of extremely short pulses in such systems. Specifically, extremely short optical pulses, consisting of two electric field oscillations, cause the appearance of a tail associated with the excitation of nonlinear waves. Due to the large spin–orbit interaction in germanene, this tail behind the main pulse is much smaller in germanene-based samples as compared to graphene-based ones, thereby making germanene a preferred material for the stable propagation of pulses along the sample.

  3. Conditional Second Order Short-crested Water Waves Applied to Extreme Wave Episodes

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2005-01-01

    A derivation of the mean second order short-crested wave pattern and associated wave kinematics, conditional on a given magnitude of the wave crest, is presented. The analysis is based on the second order Sharma and Dean finite water wave theory. A comparison with a measured extreme wave profile......, the Draupner New Year Wave, shows a good agreement in the mean, indicating that this second order wave can be a good identifier of the shape and occurrence of extreme wave events. A discussion on its use as an initial condition for a fully non-linear three-dimensional surface wave analysis is given....

  4. Circulation anomalies associated with winter temperature extremes in Athens during the period 1900-2004

    Energy Technology Data Exchange (ETDEWEB)

    Founda, D. [National Observatory of Athens (Greece). Inst. for Environmental Research and Sustainable Development; Loon, H. van [Colorado Univ., Boulder, CO (United States)

    2008-02-15

    We use the long series of temperature observed at the National Observatory of Athens, Greece, to examine the extremes of this element together with associated anomalies in the general circulation of the atmosphere. The 13 extreme-cold and 20 extreme-warm winters during the period 1900-2004 (equal to or below minus one standard deviation, and equal to or above plus one standard deviation respectively) had opposite pressure anomalies, mainly over the North Atlantic and Eurasia. The temperature extremes at Athens were representative of most of the Mediterranean and the Balkans, and their associated pressure anomalies were robust. The extremes of the Index of the North Atlantic Oscillation (the pressure difference between Gibraltar and Iceland) were not a good indicator of the temperature extremes in the Mediterranean. Rather the extreme temperature anomalies over the Mediterranean region are to a large extent controlled by a bipolar pattern of SLP (see level pressure) anomalies with centers over the British Isles and the Arctic. (orig.)

  5. Consequences of extreme life history traits on population persistence: do short-lived gobies face demographic bottlenecks?

    Science.gov (United States)

    Lefèvre, Carine D.; Nash, Kirsty L.; González-Cabello, Alonso; Bellwood, David R.

    2016-06-01

    The majority of coral reef goby species are short-lived, with some highly abundant species living less than 100 d. To understand the role and consequences of this extreme life history in shaping coral reef fish populations, we quantitatively documented the structure of small reef fish populations over a 26-month period (>14 short-lived fish generations) at an inshore reef on the Great Barrier Reef, Australia. Most species with life spans >1 yr, such as pomacentrids, exhibited a peak in recruitment during the austral summer, driving seasonal changes in the small fish community composition. In contrast, there were no clear changes in goby community composition, despite the abundance of short-lived, high turnover species. Species of Eviota, the most abundant gobiid genus observed, showed remarkably similar demographic profiles year-round, with consistent densities of adults as well as recently recruited juveniles. Our results demonstrate ongoing recruitment of these small cryptic fishes, which appears to compensate for an exceptionally short life span on the reef. Our results suggest that gobiid populations are able to overcome demographic limitations, and by maintaining reproduction, larval survival and recruitment throughout the year, they may avoid population bottlenecks. These findings also underline the potential trophodynamic importance of these small species; because of this constant turnover, Eviota species and other short-lived fishes may be particularly valuable contributors to the flow of energy on coral reefs, underpinning the year-round trophic structure.

  6. Entropies of short binary sequences in heart period dynamics.

    Science.gov (United States)

    Cysarz, D; Bettermann, H; van Leeuwen, P

    2000-06-01

    Dynamic aspects of R-R intervals have often been analyzed by means of linear and nonlinear measures. The goal of this study was to analyze binary sequences, in which only the dynamic information is retained, by means of two different aspects of regularity. R-R interval sequences derived from 24-h electrocardiogram (ECG) recordings of 118 healthy subjects were converted to symbolic binary sequences that coded the beat-to-beat increase or decrease in the R-R interval. Shannon entropy was used to quantify the occurrence of short binary patterns (length N = 5) in binary sequences derived from 10-min intervals. The regularity of the short binary patterns was analyzed on the basis of approximate entropy (ApEn). ApEn had a linear dependence on mean R-R interval length, with increasing irregularity occurring at longer R-R interval length. Shannon entropy of the same sequences showed that the increase in irregularity is accompanied by a decrease in occurrence of some patterns. Taken together, these data indicate that irregular binary patterns are more probable when the mean R-R interval increases. The use of surrogate data confirmed a nonlinear component in the binary sequence. Analysis of two consecutive 24-h ECG recordings for each subject demonstrated good intraindividual reproducibility of the results. In conclusion, quantification of binary sequences derived from ECG recordings reveals properties that cannot be found using the full information of R-R interval sequences.

  7. Prediction of short-term distributions of load extremes of offshore wind turbines

    Science.gov (United States)

    Wang, Ying-guang

    2016-12-01

    This paper proposes a new methodology to select an optimal threshold level to be used in the peak over threshold (POT) method for the prediction of short-term distributions of load extremes of offshore wind turbines. Such an optimal threshold level is found based on the estimation of the variance-to-mean ratio for the occurrence of peak values, which characterizes the Poisson assumption. A generalized Pareto distribution is then fitted to the extracted peaks over the optimal threshold level and the distribution parameters are estimated by the method of the maximum spacing estimation. This methodology is applied to estimate the short-term distributions of load extremes of the blade bending moment and the tower base bending moment at the mudline of a monopile-supported 5MW offshore wind turbine as an example. The accuracy of the POT method using the optimal threshold level is shown to be better, in terms of the distribution fitting, than that of the POT methods using empirical threshold levels. The comparisons among the short-term extreme response values predicted by using the POT method with the optimal threshold levels and with the empirical threshold levels and by using direct simulation results further substantiate the validity of the proposed new methodology.

  8. Prediction of short-term distributions of load extremes of offshore wind turbines

    Science.gov (United States)

    Wang, Ying-guang

    2016-09-01

    This paper proposes a new methodology to select an optimal threshold level to be used in the peak over threshold (POT) method for the prediction of short-term distributions of load extremes of offshore wind turbines. Such an optimal threshold level is found based on the estimation of the variance-to-mean ratio for the occurrence of peak values, which characterizes the Poisson assumption. A generalized Pareto distribution is then fitted to the extracted peaks over the optimal threshold level and the distribution parameters are estimated by the method of the maximum spacing estimation. This methodology is applied to estimate the short-term distributions of load extremes of the blade bending moment and the tower base bending moment at the mudline of a monopile-supported 5MW offshore wind turbine as an example. The accuracy of the POT method using the optimal threshold level is shown to be better, in terms of the distribution fitting, than that of the POT methods using empirical threshold levels. The comparisons among the short-term extreme response values predicted by using the POT method with the optimal threshold levels and with the empirical threshold levels and by using direct simulation results further substantiate the validity of the proposed new methodology.

  9. Estimating return periods for daily precipitation extreme events over the Brazilian Amazon

    Science.gov (United States)

    Santos, Eliane Barbosa; Lucio, Paulo Sérgio; Santos e Silva, Cláudio Moisés

    2016-11-01

    This paper aims to model the occurrence of daily precipitation extreme events and to estimate the return period of these events through the extreme value theory (generalized extreme value distribution (GEV) and the generalized Pareto distribution (GPD)). The GEV and GPD were applied in precipitation series of homogeneous regions of the Brazilian Amazon. The GEV and GPD goodness of fit were evaluated by quantile-quantile (Q-Q) plot and by the application of the Kolmogorov-Smirnov (KS) test, which compares the cumulated empirical distributions with the theoretical ones. The Q-Q plot suggests that the probability distributions of the studied series are appropriated, and these results were confirmed by the KS test, which demonstrates that the tested distributions have a good fit in all sub-regions of Amazon, thus adequate to study the daily precipitation extreme event. For all return levels studied, more intense precipitation extremes is expected to occur within the South sub-regions and the coastal area of the Brazilian Amazon. The results possibly will have some practical application in local extreme weather forecast.

  10. Sensitivities of crop models to extreme weather conditions during flowering period demonstrated for maize and winter wheat in Austria

    DEFF Research Database (Denmark)

    Eitzinger, J; Thaler, S; Schmid, E;

    2013-01-01

    The objective of the present study was to compare the performance of seven different, widely applied crop models in predicting heat and drought stress effects. The study was part of a recent suite of model inter-comparisons initiated at European level and constitutes a component that has been...... lacking in the analysis of sources of uncertainties in crop models used to study the impacts of climate change. There was a specific focus on the sensitivity of models for winter wheat and maize to extreme weather conditions (heat and drought) during the short but critical period of 2 weeks after...... or minimum tillage. Since no comprehensive field experimental data sets were available, a relative comparison of simulated grain yields and soil moisture contents under defined weather scenarios with modified temperatures and precipitation was performed for a 2-week period after flowering. The results may...

  11. Success of serial transverse enteroplasty in an adult with extreme short bowel syndrome: a case report.

    Science.gov (United States)

    Fan, Shengxian; Li, Yousheng; Zhang, Shaoyi; Wang, Jian; Li, Jieshou

    2015-04-01

    Since its introduction as an alternative intestinal lengthening technique, serial transverse enteroplasty has been increasingly used as the surgical treatment of choice for children with refractory short bowel syndrome, but there have been few reports about the adult patients. This report describes the case of a 71-year-old man with a short bowel after distal gastrectomy with Billroth II reconstruction for gastric cancer, followed by extensive intestinal resection. The serial transverse enteroplasty operation was performed and lengthened the small intestine from 49 to 67 cm. The patient tolerated the procedure well and weaned off total parenteral nutrition. Liver function also improved. This case shows that the serial transverse enteroplasty procedure increases intestinal length. This procedure should be considered a surgical option for adult patients with extreme short bowel syndrome.

  12. Short-period pulsar oscillations following a glitch

    Energy Technology Data Exchange (ETDEWEB)

    Van Eysden, C. A. [NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

    2014-07-10

    Following a glitch, the crust and magnetized plasma in the outer core of a neutron star are believed to rapidly establish a state of co-rotation within a few seconds by process analogous to classical Ekman pumping. However, in ideal magnetohydrodynamics, a final state of co-rotation is inconsistent with conservation of energy of the system. We demonstrate that, after the Ekman-like spin up is completed, magneto-inertial waves continue to propagate throughout the star, exciting torsional oscillations in the crust and plasma. The crust oscillation is irregular and quasi-periodic, with a dominant frequency of the order of seconds. Crust oscillations commence after an Alfvén crossing time, approximately half a minute at the magnetic pole, and are subsequently damped by the electron viscosity over approximately an hour. In rapidly rotating stars, the magneto-inertial spectrum in the core approaches a continuum, and crust oscillations are damped by resonant absorption analogous to quasi-periodic oscillations in magnetars. The oscillations predicted are unlikely to be observed in timing data from existing radio telescopes, but may be visible to next generation telescope arrays.

  13. Short period ionospheric perturbations from continuous Doppler sounding

    Science.gov (United States)

    Fiser, Jiri; Chum, Jaroslav; Lastovicka, Jan; Buresova, Dalia

    2017-04-01

    Results of recent observations of ionospheric perturbations on short time scales obtained by international network (Czech Republic, Argentina, Taiwan and South Africa) of multipoint continuous Doppler sounders with time resolution about 10 s are presented. Examples of observation and analysis of propagation of gravity waves (GWs), equatorial spread F (ESF), infrasound from earthquake and large convective systems, as well as ionospheric perturbations caused by solar flares will be shown. It is documented that roughly poleward propagation of GWs dominates in the local summer, whereas mainly equatorward propagation is observed in the local winter. The analysis of occurrences and zonal drifts of ESF based on Doppler sounding are consistent with optical and satellite measurements. The observations of co-seismic perturbations by Doppler sounders in the vicinity of ionosondes and seismic sensors proved that the co-seismic perturbations are caused by approximately vertically propagating infrasound waves triggered by vertical motion of the ground surface. Numerical simulations and Doppler measurements confirmed that in the vicinity (up to about 1000 km) from epicenters of strong earthquake, the infrasound propagates in nonlinear regime in the upper atmosphere, which results in the formation of N-shaped pulse. Solar flares are observed both as sudden frequency deviations and amplitude attenuations of Doppler signal.

  14. Flow of Planets Raises Short Period Fall Off

    CERN Document Server

    Taylor, Stuart F

    2012-01-01

    After finding more planets than expected at the shortest period, there has been an effort to explain their numbers by weak tidal friction. However, we find that the strength of tidal dissipation that would produce the occurence distribution found from Kepler planet candidates is different for giant versus medium radii planets. This discrepancy can be resolved if there is a "flow" of the largest planets regularly arriving such that they go through a "hot Jupiter" stage. We also show a correlation of higher stellar Fe/H with higher eccentricity of giant planets that may be from smaller planets having been sent into the star by the migration of the larger planet. This disruption of the orbits of medium and smaller planets could account for the lower occurrence of "hot Neptune" medium radius planets.

  15. Short-Period RF Undulator for a SASE Nanometer source

    Energy Technology Data Exchange (ETDEWEB)

    Jay L. Hirshfield

    2001-12-21

    Analysis is described towards development of a RF undulator with a period < 1 cm, an undulator parameter K of the order of unity, and a gap greater than 2.25 mm. The application for the undulator is for a SASE source to produce 1 nm wavelength radiation using a low energy electron beam in the range 1-2 GeV. Particle orbit calculations in a conventional standing-wave resonator configuration show that the presence of a co-propagating component of RF field can cause deleterious motion for the undulating electrons that can seriously degrade their radiation spectrum. To obviate this problem, resonator designs were devised in which only the counter-propagating field components interact with the particles. Two resonator configurations with the same undulator parameter K = 0.4 have been devised and are described in this report.

  16. Origin and Evolution of Short-period Comets

    Science.gov (United States)

    Nesvorný, David; Vokrouhlický, David; Dones, Luke; Levison, Harold F.; Kaib, Nathan; Morbidelli, Alessandro

    2017-08-01

    Comets are icy objects that orbitally evolve from the trans-Neptunian region into the inner solar system, where they are heated by solar radiation and become active due to the sublimation of water ice. Here we perform simulations in which cometary reservoirs are formed in the early solar system and evolved over 4.5 Gyr. The gravitational effects of Planet 9 (P9) are included in some simulations. Different models are considered for comets to be active, including a simple assumption that comets remain active for {N}{{p}}(q) perihelion passages with perihelion distance qmodel is compared to observations. The orbital distribution of ecliptic comets (ECs) is well reproduced in models with {N}{{p}}(2.5)≃ 500 and without P9. With P9, the inclination distribution of model ECs is wider than the observed one. We find that the known Halley-type comets (HTCs) have a nearly isotropic inclination distribution. The HTCs appear to be an extension of the population of returning Oort-cloud comets (OCCs) to shorter orbital periods. The inclination distribution of model HTCs becomes broader with increasing {N}{{p}}, but the existing data are not good enough to constrain {N}{{p}} from orbital fits. {N}{{p}}(2.5)> 1000 is required to obtain a steady-state population of large active HTCs that is consistent with observations. To fit the ratio of the returning-to-new OCCs, by contrast, our model implies that {N}{{p}}(2.5)≲ 10, possibly because the detected long-period comets are smaller and much easier to disrupt than observed HTCs.

  17. Short-period cataclysmic variables at Observatorio Astronomico Nacional IA UNAM.

    Science.gov (United States)

    Zharikov, S.

    2014-03-01

    We present results of time-resolved spectroscopy and photometry of faint (∼17-19 mag) Cataclysmic Variable stars with periods around the minimum orbital period (∼80 min). In this work we concentrated to our results of study of CVs systems which have evolved beyond the period minimum (so-called bounce-back systems). Using various instruments attached to 2.1m, 1.5m and 0.84m telescopes of OAN SPM of IA UNAM we explored conditions and structure of accretion disks in those short-period Cataclysmic Variables. We showed that the accretion disk in a system with an extremely low mass ratio (≤0.05) grows in the size reaching 2:1 resonance radius and is relatively cool. The disk in such systems also becomes largely optically thin in the continuum, contributing to the total flux less than the stellar components of the system. In contrast, the viscosity and the temperature in spiral arms formed at the outer edge of the disk are higher and their contribution in continuum plays an increasingly important role. We model such disks and generate light curves which successfully simulate the observed double-humped light curves in the quiescence. Thanks to support of our programs by the Time Allocation Commission of OAN SPM, the perfect astroclimate in the observatory, and the phase-locked method of spectroscopic observations, the significant progress in the study of bounce-back systems using a small size telescope was reached.

  18. Alessi 95 and the short period Cepheid SU Cassiopeiae

    CERN Document Server

    Turner, David G; Lane, David J; Balam, David D; Gieren, Wolfgang P; Storm, Jesper; Forbes, Doug W; Havlen, Robert J; Alessi, Bruno

    2012-01-01

    The parameters for the newly-discovered open cluster Alessi 95 are established on the basis of available photometric and spectroscopic data, in conjunction with new observations. Colour excesses for spectroscopically-observed B and A-type stars near SU Cas follow a reddening relation described by E(U-B)/E(B-V)=0.83+0.02*E(B-V), implying a value of R=Av/E(B-V)~2.8 for the associated dust. Alessi 95 has a mean reddening of E(B-V)_(B0)=0.35+-0.02 s.e., an intrinsic distance modulus of Vo-Mv=8.16+-0.04 s.e. (+-0.21 s.d.), d=429+-8 pc, and an estimated age of 10^8.2 yr from ZAMS fitting of available UBV, CCD BV, NOMAD, and 2MASS JHKs observations of cluster stars. SU Cas is a likely cluster member, with an inferred space reddening of E(B-V)=0.33+-0.02 and a luminosity of =-3.15+-0.07 s.e., consistent with overtone pulsation (P_FM=2.75 d), as also implied by the Cepheid's light curve parameters, rate of period increase, and Hipparcos parallaxes for cluster stars. There is excellent agreement of the distance estimat...

  19. On the variability of return periods of European winter precipitation extremes over the last three centuries

    Directory of Open Access Journals (Sweden)

    A. Pauling

    2007-01-01

    Full Text Available We investigate the changes of extreme European winter (December-February precipitation back to 1700 and show for various European regions that return periods of extremely wet and dry winters are subject to significant changes both before and after the onset of anthropogenic influences. Generally, winter precipitation has become more extreme. We also examine the spatial pattern of the changes of the extremes covering the last 300 years where data quality is sufficient. Over central and Eastern Europe dry winters occurred more frequently during the 18th and the second part of the 19th century relative to 1951–2000. Dry winters were less frequent during both the 18th and 19th century over the British Isles and the Mediterranean. Wet winters have been less abundant during the last three centuries compared to 1951–2000 except during the early 18th century in central Europe. Although winter precipitation extremes are affected by climate change, no obvious connection of these changes was found to solar, volcanic or anthropogenic forcing. However, physically meaningful interpretation with atmospheric circulation changes was possible.

  20. Patterns and singular features of extreme fluctuational paths of a periodically driven system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhen, E-mail: czkillua@icloud.com; Liu, Xianbin, E-mail: xbliu@nuaa.edu.cn

    2016-05-20

    Large fluctuations of an overdamped periodically driven oscillating system are investigated theoretically and numerically in the limit of weak noise. Optimal paths fluctuating to certain point are given by statistical analysis using the concept of prehistory probability distribution. The validity of statistical results is verified by solutions of boundary value problem. Optimal paths are found to change topologically when terminating points lie at opposite side of a switching line. Patterns of extreme paths are plotted through a proper parameterization of Lagrangian manifold having complicated structures. Several extreme paths to the same point are obtained by multiple solutions of boundary value solutions. Actions along various extreme paths are calculated and associated analysis is performed in relation to the singular features of the patterns. - Highlights: • Both extreme and optimal paths are obtained by various methods. • Boundary value problems are solved to ensure the validity of statistical results. • Topological structure of Lagrangian manifold is considered. • Singularities of the pattern of extreme paths are studied.

  1. Staggered and short period solutions of the Saturable Discrete Nonlinear Schr\\"odinger Equation

    CERN Document Server

    Khare, Avinash; Samuelsen, Mogens R; Saxena, Avadh; 10.1088/1751-8113/42/8/085002

    2010-01-01

    We point out that the nonlinear Schr{\\"o}dinger lattice with a saturable nonlinearity also admits staggered periodic as well as localized pulse-like solutions. Further, the same model also admits solutions with a short period. We examine the stability of these solutions and find that the staggered as well as the short period solutions are stable in most cases. We also show that the effective Peierls-Nabarro barrier for the pulse-like soliton solutions is zero.

  2. Effect of Dampers on Seismic Demand of Short Period Structures in Soft Sites

    Directory of Open Access Journals (Sweden)

    Nazzal S. Armouti

    2013-02-01

    Full Text Available Seismic behavior of short period structures with dampers founded on soft soil is investigated. A Single bay frame with diagonal damper that represents short period structures is evaluated in response to the excitation of a set of earthquake records. The frame system is modeled as a Generalized Single Degree of Freedom System, and is subjected to five earthquake records representative of soft site conditions. The relationship between the force modification factor and the global ductility demand for short period structures founded on soft soil, in the presence of dampers, tends to approach those of long period ones. Compared with seismic demand under general site conditions, short period structures founded on soft soil show higher seismic demand and high sensitivity to earthquake excitations. Similar to seismic demand in general site conditions, and except for period of 0.1 sec, short period structures in soft sites with dampers having damping ratios higher than 20% tend to keep the structural response in the elastic range even for high values of force reductions. Seismic code provisions should be revised to account for short period effect under seismic excitation.

  3. On the variability of return periods of European winter precipitation extremes over the last five centuries

    Directory of Open Access Journals (Sweden)

    A. Pauling

    2006-04-01

    Full Text Available We investigate the changes of extreme European winter (December–February precipitation over the last half millennium and show for various European regions that return periods of extremely wet and dry winters are subject to significant changes both before and after the onset of anthropogenic influences. Additionally, we examine the spatial pattern of the changes of the extremes covering the last 300 years where data quality is sufficient. Over central and eastern Europe dry winters occurred more frequently during the 18th and the second part of the 19th century relative to 1951–2000. Dry winters were less frequent during both the 18th and 19th century over the British Isles and the Mediterranean. Wet winters have been less abundant during the last three centuries compared to 1951–2000 except during the early 18th century in central Europe. Although winter precipitation extremes are affected by climate change, no obvious connection of these changes was found to solar, volcanic or anthropogenic forcing. However, physically meaningful interpretation with atmospheric circulation changes was possible.

  4. Search for circum-planetary material and orbital period variations of short-period Kepler exoplanet candidates

    Science.gov (United States)

    Garai, Z.; Zhou, G.; Budaj, J.; Stellingwerf, R. F.

    2014-12-01

    A unique short-period ({P = 0.65356(1)} d) Mercury-size Kepler exoplanet candidate KIC012557548b has been discovered recently by {Rappaport et al. (2012)}. This object is a transiting disintegrating exoplanet with a circum-planetary material-comet-like tail. Close-in exoplanets, like KIC012557548b, are subjected to the greatest planet-star interactions. This interaction may have various forms. In certain cases it may cause formation of the comet-like tail. Strong interaction with the host star, and/or presence of an additional planet may lead to variations in the orbital period of the planet. Our main aim is to search for comet-like tails similar to KIC012557548b and for long-term orbital period variations. We are curious about frequency of comet-like tail formation among short-period Kepler exoplanet candidates. We concentrate on a sample of 20 close-in candidates with a period similar to KIC012557548b from the Kepler mission. We first improved the preliminary orbital periods and obtained the transit light curves. Subsequently we searched for the signatures of a circum-planetary material in these light curves. For this purpose the final transit light curve of each planet was fitted with a theoretical light curve, and the residuals were examined for abnormalities. We then searched for possible long-term changes of the orbital periods using the method of phase dispersion minimization. In 8 cases out of 20 we found some interesting peculiarities, but none of the exoplanet candidates showed signs of a comet-like tail. It seems that the frequency of comet-like tail formation among short-period Kepler exoplanet candidates is very low. We searched for comet-like tails based on the period criterion. Based on our results we can conclude that the short-period criterion is not enough to cause comet-like tail formation. This result is in agreement with the theory of the thermal wind and planet evaporation (Perez-Becker & Chiang 2013). We also found 3 cases of candidates which

  5. THE CHAOTIC DETECTION OF PERIODIC SHORT-IMPULSE SIGNALS UNDER STRONG NOISE BACKGROUND

    Institute of Scientific and Technical Information of China (English)

    Li Yue; Yang Baojun

    2002-01-01

    The periodic short-impulse signals under strong noise background are successfully detected with a special chaotic system invented by the authors. Simulation experiments show that the chaotic system is very sensitive to periodic short-impulse signals submerged by strong noise background, and it can effectively restrain any zero-mean noise. The system has a stable working-detection limit of -83dB.

  6. Changes in Seasonal Cycle and Extremes in China during the Period 1960—2008

    Institute of Scientific and Technical Information of China (English)

    YAN Zhongwei; XIA Jiangjiang; QIAN Cheng; ZHOU Wen

    2011-01-01

    Recent trends in seasonal cycles in China are analyzed, based on a homogenized datnset of daily temperatures at 541 stations during the period 1960-2008. Several indices are defined for describing the key features of a seasonal cycle, including local winter/summer (LW/LS) periods and local spring/autumn phase (LSP/LAP). The Ensemble Empirical Mode Decomposition method is applied to determine the indices for each year. The LW period was found to have shortened by 2-6 d (10 yr)-1, mainly due to an earlier end to winter conditions, with the LW mean temperature having increased by 0.2°C-0.4°C (10 yr)-1, over almost all of China. Records of the most severe climate extremes changed less than more typical winter conditions did. The LS period was found to have lengthened by 2-4 d (10 yr)-1, due to progressively earlier onsets and delayed end dates of the locally defined hot period. The LS mean temperature increased by 0.1°C-0.2°C (10 yr)-1 in most of China, except for a region in southern China centered on the mid-lower reaches of the Yangtze River. In contrast to the winter cases, the warming trend in summer was more prominent in the most extreme records than in those of more typical summer conditions. The LSP was found to have advanced significantly by about 2 d (10 yr)-1 in most of China. Changes in the autumn phase were less prominent. Relatively rapid changes happened in the 1980s for most of the regional mean indices dealing with winter and in the 1990s for those dealing with summer.

  7. A Survey for Very Short-Period Planets in the Kepler Data

    CERN Document Server

    Jackson, Brian; Adams, Elisabeth R; Chambers, John; Deming, Drake

    2013-01-01

    We conducted a search for very short-period transiting objects in the publicly available Kepler dataset. Our preliminary survey has revealed thirteen planetary candidates, with periods ranging from 3.3 to 10 hours. We have analyzed the data for these candidates using photometric models that include transit light curves, ellipsoidal variations, and secondary eclipses, to constrain the candidates' radii, masses, and effective temperatures. Even with masses of only a few Earth masses, the candidates' short periods mean they may induce stellar radial velocity signals (about 10 m/s), detectable by currently operating facilities. The origins of such short-period planets are unclear, but we discuss the possibility that they may be the remnants of disrupted hot Jupiters. Whatever their origins, if confirmed as planets, these candidates would be among the shortest-period planets ever discovered, and if common, such planets would be particularly amenable to discovery by the planned TESS mission, which is specifically d...

  8. A survey for very short-period planets in the Kepler data

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Brian; Stark, Christopher C.; Chambers, John [Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Adams, Elisabeth R. [Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719 (United States); Deming, Drake, E-mail: bjackson@dtm.ciw.edu [Department of Astronomy, University of Maryland at College Park, College Park, MD 20742 (United States)

    2013-12-20

    We conducted a search for very short-period transiting objects in the publicly available Kepler data set. Our preliminary survey has revealed four planetary candidates, all with orbital periods less than 12 hr. We have analyzed the data for these candidates using photometric models that include transit light curves, ellipsoidal variations, and secondary eclipses to constrain the candidates' radii, masses, and effective temperatures. Even with masses of only a few Earth masses, the candidates' short periods mean that they may induce stellar radial velocity signals (a few m s{sup –1}) detectable by currently operating facilities. The origins of such short-period planets are unclear, but we discuss the possibility that they may be the remnants of disrupted hot Jupiters. Whatever their origins, if confirmed as planets, these candidates would be among the shortest-period planets ever discovered. Such planets would be particularly amenable to discovery by the planned TESS mission.

  9. Trends and periodicity of daily temperature and precipitation extremes during 1960-2013 in Hunan Province, central south China

    Science.gov (United States)

    Chen, Ajiao; He, Xinguang; Guan, Huade; Cai, Yi

    2017-02-01

    In this study, the trends and periodicity in climate extremes are examined in Hunan Province over the period 1960-2013 on the basis of 27 extreme climate indices calculated from daily temperature and precipitation records at 89 meteorological stations. The results show that in the whole province, temperature extremes exhibit a warming trend with more than 50% stations being statistically significant for 7 out of 16 temperature indices, and the nighttime temperature increases faster than the daytime temperature at the annual scale. The changes in most extreme temperature indices show strongly coherent spatial patterns. Moreover, the change rates of almost all temperature indices in north Hunan are greater than those of other regions. However, the statistically significant changes in indices of extreme precipitation are observed at fewer stations than in extreme temperature indices, forming less spatially coherent patterns. Positive trends in indices of extreme precipitation show that the amount and intensity of extreme precipitation events are generally increasing in both annual and seasonal scales, whereas the significant downward trend in consecutive wet days indicates that the precipitation becomes more even over the study period. Analysis of changes in probability distributions of extreme indices for 1960-1986 and 1987-2013 also demonstrates a remarkable shift toward warmer condition and increasing tendency in the amount and intensity of extreme precipitation during the past decades. The variations in extreme climate indices exhibit inconstant frequencies in the wavelet power spectrum. Among the 16 temperature indices, 2 of them show significant 1-year periodic oscillation and 7 of them exhibit significant 4-year cycle during some certain periods. However, significant periodic oscillations can be found in all of the precipitation indices. Wet-day precipitation and three absolute precipitation indices show significant 1-year cycle and other seven provide

  10. Application of radar data to estimate distributed return periods of extreme rainfall events over Trondheim

    Energy Technology Data Exchange (ETDEWEB)

    Abdella, Yisak Sultan

    2013-07-01

    The return period of a given rainfall intensity is an important parameter for the Trondheim municipality since the drainage systems in Trondheim have been and are still being designed on the basis of a selected return period. Since rainfall is a spatially distributed phenomenon, a single event passing over a city can yield different return periods at different locations in the same city. In order to account for this spatial variability, a tool has been developed in this project for determining distributed return periods for rainfall events over Trondheim using the measurements from Rissa radar. The tool includes a method for adjusting radar rainfall using rain gauge measurements and an accumulation technique which accounts for storm movement and temporal variation in intensity. The tool has been tested on two extreme events which occurred on July 29 2007 and August 13 2007. The application on the two events has demonstrated a fully-automated estimation of distributed return periods using readily available data. For the particular rain gauge network in Trondheim, it has also been shown how areas of maximum intensity observed by the radar can be missed by all the gauges. (author)

  11. Formation and erasure of population difference gratings in the coherent interaction of a resonant medium with extremely short optical pulses

    Science.gov (United States)

    Arkhipov, R. M.; Arkhipov, M. V.; Babushkin, I.; Rosanov, N. N.

    2016-11-01

    In the regime of coherent interaction of short optical pulses with a resonant medium, which is implemented with a pulse duration shorter than the relaxation times in the medium, the formation of population gratings can occur without overlapping the pulses therein. In this case, there are new possibilities for controlling optical pulses, which are especially pronounced for extremely short pulses. It is shown that, with the proper choice of the parameters of a sequence of extremely short optical pulses, not only the formation of population gratings, but also their erasure are possible. It is demonstrated that this effect can be used for the creation of an ultrahigh-speed optical deflector.

  12. Seasonal precipitation extreme indices in mainland Portugal: trends and variability in the period 1941-2007

    Science.gov (United States)

    Santo, Fátima E.; Ramos, Alexandre M.; de Lima, M. Isabel P.; Trigo, Ricardo M.

    2013-04-01

    Changes in the precipitation regimes are expected to be accompanied by variations in the occurrence of extreme events, which in turn could be related to low frequency variability. The impact on the society and environment requires that the regional specificities are understood. For mainland Portugal, this work reports the results of the analysis of trends in selected precipitation indices calculated from daily precipitation data from 57 meteorological stations, recorded in the period 1941-2007; additionally we have also investigated the correlations between these indices and several modes of low frequency variability over the area. We focus on exploring regional differences and seasonal variations in the intensity, frequency and duration of extreme precipitation events. The precipitation indices were assessed at the seasonal scale and calculated at both the station and regional scales. Results sometimes highlight marked changes in seasonal precipitation and show that: i) trends in spring and autumn have opposite signals: statistically significant drying trends in the spring are accompanied by a reduction in precipitation extremes; in autumn, wetting trends are detected for all precipitation indices, although overall they are not significant at the 5% level; ii) there seems to be a tendency for a reduction in the duration of the rainy season; iii) the North Atlantic Oscillation (NAO) is the mode of variability that has the highest influence on precipitation extremes over mainland Portugal, particularly in the winter and autumn, and is one of the most important teleconnection patterns in all seasons. This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) through project STORMEx FCOMP-01-0124-FEDER-019524 (PTDC/AAC-CLI/121339/2010).

  13. Reduced Maxwell-Duffing description of extremely short pulses in nonresonant media.

    Science.gov (United States)

    Kazantseva, Elena V; Maimistov, Andrei I; Caputo, Jean-Guy

    2005-05-01

    The propagation of extremely short pulses of an electromagnetic field (electromagnetic spikes) is considered in the framework of a model wherein the material medium is represented by anharmonic oscillators with cubic nonlinearities (Duffing model) and waves can propagate only in the right direction. The system of reduced Maxwell-Duffing equations admits two families of exact analytical solutions in the form of solitary waves. These are bright spikes propagating on a zero background, and bright and dark spikes propagating on a nonzero background. We find that these steady-state pulses are stable in terms of boundedness of the Hamiltonian. Direct simulations demonstrate that these pulses are very robust against perturbations. We find that a high-frequency modulated electromagnetic pulse evolves into a breather-like one. Conversely, a low frequency pulse transforms into a quasiharmonic wave.

  14. Comparison of calculated brightness and flux of radiation from a long-period wiggler and a short-period undulator.

    Science.gov (United States)

    Shaftan, T; Hulbert, S L; Berman, L

    2008-07-01

    In this article the calculation of brightness and flux for two insertion devices of the 2.8 GeV X-ray storage ring at the NSLS is discussed. The radiation properties from the X25 linearly polarized wiggler and the new X25 short-period undulator are compared at a fixed photon energy (11.3 keV) corresponding to emission from the fifth harmonic of the short-period undulator. For this computation, three commonly available synchrotron radiation programs are used. The capabilities of each of these codes are briefly discussed, and their range of applicability are commented on. It is concluded that special care is needed when modeling the radiation of the classes of insertion devices considered here.

  15. Staggered and short-period solutions of the saturable discrete nonlinear Schrodinger equation

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, K.O.; Samuelsen, Mogens Rugholm

    2009-01-01

    We point out that the nonlinear Schrodinger lattice with a saturable nonlinearity also admits staggered periodic aswell as localized pulse-like solutions. Further, the same model also admits solutions with a short period. We examine the stability of these solutions and find that the staggered...

  16. Search for a circum-planetary material and orbital period variations of short-period Kepler exoplanet candidates

    CERN Document Server

    Garai, Z; Budaj, J; Stellingwerf, R F

    2014-01-01

    A unique short-period Mercury-size Kepler exoplanet candidate KIC012557548b has been discovered recently by Rappaport et al. (2012). This object is a transiting disintegrating exoplanet with a circum-planetary material - comet-like tail. Close-in exoplanets, like KIC012557548b, are subjected to the greatest planet-star interactions. This interaction may have various forms. In certain cases it may cause formation of the comet-like tail. Strong interaction with the host star, and/or presence of an additional planet may lead to variations in the orbital period of the planet. Our main aim is to search for comet-like tails similar to KIC012557548b and for long-term orbital period variations. We are curious about frequency of comet-like tail formation among short-period Kepler exoplanet candidates. We concentrate on a sample of 20 close-in candidates with a period similar to KIC012557548b from the Kepler mission.

  17. Closed gastroschisis, vanishing midgut and extreme short bowel syndrome: Case report and review of the literature.

    Science.gov (United States)

    Dennison, F A

    2016-08-01

    Gastroschisis alone has excellent survival rates. Occasionally reported is closed gastroschisis, leading to vanishing small bowel and extreme short bowel syndrome. It is believed that the abdominal wall defect can contract or close in utero, which leads to strangulation of the eviscerated bowel and the rare "vanishing gut syndrome." This has a very poor prognosis with mortality as high as 70%. An 18-year-old primigravid patient's 13 week scan diagnosed a large gastroschisis affecting the fetus. After counselling, she decided to continue with the pregnancy. Between 20 and 22 weeks, the gastroschisis disappeared, and the bowel within the abdomen became markedly dilated. Spontaneous labour occurred at 33 + 3 weeks gestation. There was no abdominal wall defect seen at delivery. Imaging and an exploratory laparotomy demonstrated absence of most of the midgut. Because available options for treatment would be very aggressive and risky, palliative care was thought to be the most feasible and practical option. He died at home on day 29 after birth. Extreme short gut syndrome (less than 25 cm of remaining small bowel) is rare. There are 13 reported cases in the literature from year 2000 to 2013. Treatment is aggressive and involves a bowel lengthening procedure or small bowel transplant. All require total parenteral nutrition and liver failure, and liver transplant is a common complication. Of these cases, 12 were born alive and 7 had aggressive treatment. Only two cases were confirmed to still be alive in infancy. If gastroschisis is seen to be reducing and "disappearing" antenatally, parents should be made aware of this rare complication so that they might be prepared if a poor outcome is anticipated.

  18. Short time step continuous rainfall modeling and simulation of extreme events

    Science.gov (United States)

    Callau Poduje, A. C.; Haberlandt, U.

    2017-09-01

    The design, planning, operation and overall assessment of urban drainage systems require long and continuous rain series in a high temporal resolution. Unfortunately, the availability of this data is usually short. Nevertheless a precipitation model could be used to tackle this shortcoming; therefore it is in the aim of this study to present a stochastic point precipitation model to reproduce average rainfall event properties along with extreme values. For this purpose a model is proposed to generate long synthetic series of rainfall for a temporal resolution of 5 min. It is based on an alternating renewal framework and events are characterized by variables describing durations, amounts and peaks. A group of 24 stations located in the north of Germany is used to set up and test the model. The adequate modeling of joint behaviour of rainfall amount and duration is found to be essential for reproducing the observed properties, especially for the extreme events. Copulas are advantageous tools for modeling these variables jointly; however caution must be taken in the selection of the proper copula. The inclusion of seasonality and small events is as well tested and found to be useful. The model is directly validated by generating long synthetic time series and comparing them with observed ones. An indirect validation is as well performed based on a fictional urban hydrological system. The proposed model is capable of reproducing seasonal behaviour and main characteristics of the rainfall events including extremes along with urban flooding and overflow behaviour. Overall the performance of the model is acceptable compared to the design practice. The proposed model is simple to interpret, fast to implement and to transfer to other regions, whilst showing acceptable results.

  19. Assessing the short-term effects of an extreme storm on Mediterranean forest raptors

    Science.gov (United States)

    Martínez, José E.; Jiménez-Franco, María V.; Zuberogoitia, Iñigo; León-Ortega, Mario; Calvo, José F.

    2013-04-01

    Different species show different responses to natural disturbances, depending on their capacity to exploit the altered environment and occupy new niches. In the case of semi-arid Mediterranean areas, there is no information available on the response of bird communities to disturbance caused by extreme weather events. Here, we evaluate the short-term effects of a heavy snowfall and strong winds on three long-lived species of forest-dwelling raptor in a semi-arid Mediterranean region situated in the south-east of Spain. The loss of nests was significantly higher in the first and second years following the disturbance than in the third year. The three species studied exhibited great tolerance to the short-term effects of the storm since we found no differences in density or reproductive parameters between the nine breeding seasons prior to the disturbance and the three which immediately followed it. We suggest that the tolerance shown by these three species to windstorms in semi-arid Mediterranean zones could be an adaptive response, resulting from the climatic and human pressures which have prevailed from the Bronze Age to the present day.

  20. Short-period X-ray oscillations in super-soft novae and persistent SSS

    CERN Document Server

    Ness, J -U; Osborne, J P; Kuulkers, E; Henze, M; Piro, A L; Drake, J J; Dobrotka, A; Schwarz, G; Starrfield, S; Kretschmar, P; Hirsch, M; Wilms, J

    2015-01-01

    Transient short-period <100s oscillations have been found in the X-ray light curves of three novae during their SSS phase and in one persistent SSS. We pursue an observational approach to determine possible driving mechanisms and relations to fundamental system parameters such as the white dwarf mass. We performed a systematic search for short-period oscillations in all available XMM-Newton and Chandra X-ray light curves of persistent SSS and novae during their SSS phase. To study time evolution, we divided each light curve into short time segments and computed power spectra. We then constructed dynamic power spectra from which we identified transient periodic signals even when only present for a short time. From all time segments of each system, we computed fractions of time when periodic signals were detected. In addition to the previously known systems with short-period oscillations, RS Oph (35s), KT Eri (35s), V339 Del (54s), and Cal 83 (67s), we found one additional system, LMC 2009a (33s), and also c...

  1. Effects of age, gender, and stimulus presentation period on visual short-term memory.

    Science.gov (United States)

    Kunimi, Mitsunobu

    2016-01-01

    This study focused on age-related changes in visual short-term memory using visual stimuli that did not allow verbal encoding. Experiment 1 examined the effects of age and the length of the stimulus presentation period on visual short-term memory function. Experiment 2 examined the effects of age, gender, and the length of the stimulus presentation period on visual short-term memory function. The worst memory performance and the largest performance difference between the age groups were observed in the shortest stimulus presentation period conditions. The performance difference between the age groups became smaller as the stimulus presentation period became longer; however, it did not completely disappear. Although gender did not have a significant effect on d' regardless of the presentation period in the young group, a significant gender-based difference was observed for stimulus presentation periods of 500 ms and 1,000 ms in the older group. This study indicates that the decline in visual short-term memory observed in the older group is due to the interaction of several factors.

  2. Lower-Extremity Weakness in a Teenager Due to Thyrotoxic Periodic Paralysis.

    Science.gov (United States)

    Thornton, Matthew D

    2017-04-01

    Thyrotoxic hypokalemic paralysis is the hallmark of thyrotoxic periodic paralysis (TPP). TPP is a potentially deadly complication of hyperthyroidism that occurs because of rapid and dramatic intracellular shift of potassium. This transference results in severe hypokalemia and clinically manifests itself as muscle weakness or paralysis. This condition predominantly affects males of Asian descent, and its presentation can range from mild to severe, as seen in our case. We present the case of a 15-year-old Asian-American male who presented to a tertiary-care pediatric emergency department complaining of generalized weakness and flaccid paralysis of his lower extremities. The differential for such a complaint is extremely broad, and the symptoms can result from etiologies arising from the cerebral cortex, the spinal cord, peripheral nerves, the neuromuscular junction, or even the muscles themselves. Our patient was found to have an extremely low serum potassium concentration, as well as an electrocardiogram that revealed a prolonged QT interval and right bundle branch block. The etiology of these abnormalities and the patient's symptoms was found to be undiagnosed and uncontrolled hyperthyroidism from Grave's disease, which resulted in this dramatic presentation of thyrotoxic hypokalemic paralysis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This entity is common in Asia but still somewhat rare in the United States and other Western countries. Our case illustrates that careful history taking and a focused diagnostic evaluation, in conjunction with having an awareness of this disease, can help expedite diagnosis and management, as well as avoid unnecessary and potential harmful testing in the emergency department setting. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Short- and Long-term Pulmonary Outcome of Palivizumab in Children Born Extremely Prematurely.

    Science.gov (United States)

    Prais, Dario; Kaplan, Eytan; Klinger, Gil; Mussaffi, Huda; Mei-Zahav, Meir; Bar-Yishay, Ephraim; Stafler, Patrick; Steuer, Guy; Sirota, Lea; Blau, Hannah

    2016-03-01

    Palivizumab reduces the severity of respiratory syncytial virus infection in premature infants, but whether there is a protective effect beyond the preschool age is unknown. This study sought to assess the short- and long-term effects of palivizumab immunization on respiratory morbidity and pulmonary function at school age in children born extremely prematurely. Infants born before 29 weeks' gestation in 2000 to 2003 were assessed at school age by parental questionnaire, hospital chart review, and lung function tests. Children born immediately before the introduction of routine palivizumab prophylaxis were compared with age-matched children who received palivizumab prophylaxis during the first respiratory syncytial virus season. Sixty-three children with a mean age 8.9 years were included: 30 had received palivizumab and 33 had not (control subjects). The groups were similar in terms of gestational age, birth weight, need for mechanical ventilation, and oxygen supplementation. Fifty-three percent of the palivizumab group, compared with 39% of the control group, had bronchopulmonary dysplasia (P = .14). Wheezing occurred in the first 2 years of life in 27% of the palivizumab group and in 70% of control subjects (P = .008); respective hospitalization rates were 33% and 70% (P = .001). At school age, rates of hyperresponsiveness (provocative concentration leading to a 20% fall in FEV1 < 1 mg/mL) were 33% and 48%, respectively (P = .38). Spirometry, lung volumes, diffusion, and exhaled nitric oxide were within normal limits, with no significant differences between groups. Palivizumab prophylaxis was associated with reduced wheezing episodes and hospitalizations during the first 2 years of life in children born extremely prematurely. However, it did not affect pulmonary outcome at school age. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  4. Chronic calcium pyrophosphate crystal inflammatory arthritis induced by extreme hypomagnesemia in short bowel syndrome

    Directory of Open Access Journals (Sweden)

    Hahn Markus

    2012-09-01

    Full Text Available Abstract Background Short bowel syndrome (SBS may induce a plethora of clinical symptoms ranging from underweight to nutrient-, vitamin- and electrolyte deficiencies. The objective of this case report is to illustrate how demanding the management of a 60 year old patient with SBS and recurrent joint attacks was for different medical disciplines. Case presentation The patient with SBS presented with a body mass index of 16.5 kg/m2 after partial jejunoileal resection of the small intestine with a six year long history of recurrent pain attacks in multiple peripheral joints, chronic diarrhoea and food intolerances. Pain attacks occurred 4–5 times a week with a median consumption of 15 mg prednisone per day. The interdisciplinary workup after several gastroenterologic, rheumatologic, radiologic, psychiatric and orthopedic consultations is shown including successful treatment steps. Clinical diagnosis revealed no systemic inflammatory disease, but confirmed extreme hypomagnesemia (0.2 mmol/l after reproducible pathological magnesium resorption tests as causative for chronic calcium pyrophosphate crystal inflammatory arthritis (pseudogout, chondrocalcinosis. Multidisciplinary treatment included application of colchicines, parenteral nutrition and magnesium substitution, antiperistaltic agents and avoidance of intolerant foods. Normalization of magnesium levels and a marked remission of joint attacks were achieved after six months with significant reduction of prednisone to 1.5 mg/day. Conclusion Despite the rarity of this condition, it is important to know that hypomagnesaemia may be associated with calcium pyrophosphate crystal inflammatory arthritis (chondrocalcinosis and that SBS patients may be prone to develop extreme hypomagnesaemia causing recurrent joint attacks without systemic inflammation.

  5. Short period light variation of the Algol-type binary U Coronae Borealis

    Science.gov (United States)

    Narusawa, Shin-Ya; Waki, Yoshifumi; Ioroi, Masayuki; Nakamura, Yasuhisa; Takeuti, Mine

    The short period variability in the light curve of U CrB, an Algol-type binary, was examined with the published data of van Gent (1989). The period of variability was approximately 0.05 d and the amplitude was 0.05 mag. The superposition of several modes was suggested. The properties of the light variability were compared with those of the early-type main-sequence pulsating stars.

  6. Ultra-Short-Period Planets in K2: New Results From SuPerPiG

    Science.gov (United States)

    Adams, Elisabeth; Jackson, Brian; Endl, Michael

    2016-10-01

    Ultra-short-period planets, with orbital periods of less than 1 day, are a challenge to theories of planet formation. The SuPerPiG collaboration (Short-Period Planet Group) reports on 19 candidates identified in Campaigns 0-5 of the K2 mission. Planet candidates range in size from 0.7-16 Earth radii and in orbital period from 4.2 to 23.5 hours. One candidate (EPIC 203533312, Kp=12.5) is among the shortest-period planet candidates discovered to date (P=4.2 hours), and, if confirmed as a planet, must have a density of at least rho=8.9 g/cm^3 in order to not be tidally disrupted. Five candidates have nominal radius values in the sub-Jovian desert (R_P=3-11 R_E and P<=1.5 days) where theoretical models do not favor their long-term stability; the only confirmed planet in this range is thought to be disintegrating (EPIC 201637175). Based on an assessment of our survey's completeness, we estimate an occurrence rate for ultra-short-period planets among K2 target stars that is about half that estimated from the Kepler sample, raising questions as to whether K2 systems are intrinsically different from Kepler systems, possibly as a result of their different galactic location.

  7. Local short-duration precipitation extremes in Sweden: observations, forecasts and projections

    Science.gov (United States)

    Olsson, Jonas; Berg, Peter; Simonsson, Lennart

    2015-04-01

    Local short-duration precipitation extremes (LSPEs) are a key driver of hydrological hazards, notably in steep catchments with thin soils and in urban environments. The triggered floodings, landslides, etc., have large consequences for society in terms of both economy and health. Accurate estimations of LSPEs on both climatological time-scales (past, present, future) and in real-time is thus of great importance for improved hydrological predictions as well as design of constructions and infrastructure affected by hydrological fluxes. Analysis of LSPEs is, however, associated with various limitations and uncertainties. These are to a large degree associated with the small-scale nature of the meteorological processes behind LSPEs and the associated requirements on observation sensors as well as model descriptions. Some examples of causes for the limitations involved are given in the following. - Observations: High-resolution data sets available for LSPE analyses are often limited to either relatively long series from one or a few stations or relatively short series from larger station networks. Radar data have excellent resolutions in both time and space but the estimated local precipitation intensity is still highly uncertain. New and promising techniques (e.g. microwave links) are still in their infancy. - Weather forecasts (short-range): Although forecasts with the required spatial resolution for potential generation of LSPEs (around 2-4 km) are becoming operationally available, the actual forecast precision of LSPEs is largely unknown. Forecasted LSPEs may be displaced in time or, more critically, in space which strongly affects the possibility to assess hydrological risk. - Climate projections: The spatial resolution of the current RCM generation (around 25 km) is not sufficient for proper description of LSPEs. Statistical post-processing (i.e. downscaling) is required which adds substantial uncertainty to the final result. Ensemble generation of sufficiently

  8. A Population of Short-Period Variable Quasars from PTF as Supermassive Black Hole Binary Candidates

    CERN Document Server

    Charisi, M; Haiman, Z; Price-Whelan, A M; Graham, M J; Bellm, E C; Laher, R R; Marka, S

    2016-01-01

    Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circumbinary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35,383 spectroscopically confirmed quasars in the photometric database of the Palomar Transient Factory (PTF). We analysed Lomb-Scargle periodograms and assessed the significance of our findings by modeling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PT...

  9. Periodic Homoclinic Wave of (1+1)-Dimensional Long-Short Wave Equation

    Institute of Scientific and Technical Information of China (English)

    LI Dong-Long; DAI Zheng-De; GUO Yan-Feng

    2008-01-01

    @@ The exact periodic homoclinic wave of (1+1) D long-short wave equation is obtained using an extended homoclinic test technique.This result shows complexity and variety of dynamical behaviour for a (1+1)-dimensional longshort wave equation.

  10. ExploreNEOs. VIII. Dormant Short-period Comets in the Near-Earth Asteroid Population

    Science.gov (United States)

    Mommert, M.; Harris, A. W.; Mueller, M.; Hora, J. L.; Trilling, D. E.; Bottke, W. F.; Thomas, C. A.; Delbo, M.; Emery, J. P.; Fazio, G.; Smith, H. A.

    2015-10-01

    We perform a search for dormant comets, asteroidal objects of cometary origin, in the near-Earth asteroid (NEA) population based on dynamical and physical considerations. Our study is based on albedos derived within the ExploreNEOs program and is extended by adding data from NEOWISE and the Akari asteroid catalog. We use a statistical approach to identify asteroids on orbits that resemble those of short-period near-Earth comets (NECs) using the Tisserand parameter with respect to Jupiter, the aphelion distance, and the minimum orbital intersection distance with respect to Jupiter. From the sample of NEAs on comet-like orbits, we select those with a geometric albedo pV ≤ 0.064 as dormant comet candidates, and find that only ˜50% of NEAs on comet-like orbits also have comet-like albedos. We identify a total of 23 NEAs from our sample that are likely to be dormant short-period NECs and, based on a de-biasing procedure applied to the cryogenic NEOWISE survey, estimate both magnitude-limited and size-limited fractions of the NEA population that are dormant short-period comets. We find that 0.3%-3.3% of the NEA population with H ≤ 21, and ({9}-5+2)% of the population with diameters d ≥ 1 km, are dormant short-period NECs.

  11. On the Eccentricity Distribution of Short-Period Single-Planet Systems

    CERN Document Server

    Wang, Ji

    2011-01-01

    We apply standard Markov chain Monte Carlo (MCMC) analysis techniques for 50 short- period, single-planet systems discovered with radial velocity technique. We develop a new method for accessing the significance of a non-zero orbital eccentricity, namely {\\Gamma} analysis, which combines frequentist bootstrap approach with Bayesian analysis of each simulated data set. We find the eccentricity estimations from {\\Gamma} analysis are generally consistent with results from both standard MCMC analysis and previous references. The {\\Gamma} method is particular useful for assessing the significance of small eccentricities. Our results suggest that the current sample size is insufficient to draw robust conclusions about the roles of tidal interaction and perturbations in shaping the eccentricity distribution of short-period single-planet systems. We use a Bayesian population analysis to show that a mixture of analytical distributions is a good approximation of the underlying eccentricity distribution. For short-perio...

  12. Quasi-Periodic Oscillations and broadband variability in short magnetar bursts

    CERN Document Server

    Huppenkothen, Daniela; Uttley, Phil; van der Horst, Alexander J; van der Klis, Michiel; Kouveliotou, Chryssa; Gogus, Ersin; Granot, Jonathan; Vaughan, Simon; Finger, Mark H

    2012-01-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to search for QPOs, such analysis is seriously data limited. We set out a procedure for doing QPO searches in the far more numerous, short, less energetic magnetar bursts. The short, transient nature of these bursts requires the implementation of sophisticated statistical techniques to make reliable inferences. Using Bayesian statistics, we model the periodogram as a combination of red noise at low frequencies and white noise at high frequencies, which we show is a conservative approach to the problem. We use empirical models to make inferences about the potential signature of periodic and quasi-periodic oscillations at these frequencies. We compare our method with previously used techniques and find that although it is on the whole more conservative, it is also more reliable in ...

  13. Planet Hunters: Assessing the Kepler Inventory of Short-period Planets

    Science.gov (United States)

    Schwamb, Megan E.; Lintott, Chris J.; Fischer, Debra A.; Giguere, Matthew J.; Lynn, Stuart; Smith, Arfon M.; Brewer, John M.; Parrish, Michael; Schawinski, Kevin; Simpson, Robert J.

    2012-08-01

    We present the results from a search of data from the first 33.5 days of the Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters citizen science project. Planet Hunters enlists members of the general public to visually identify transits in the publicly released Kepler light curves via the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data set. We examine the abundance of >=2 R ⊕ planets on short-period (=4 R ⊕ Planet Hunters >=85% efficient at identifying transit signals for planets with periods less than 15 days for the Kepler sample of target stars. Our high efficiency rate for simulated transits along with recovery of the majority of Kepler >=4 R ⊕ planets suggests that the Kepler inventory of >=4 R ⊕ short-period planets is nearly complete.

  14. Looking for Very Short-Period Planets with Re-Purposed Kepler

    CERN Document Server

    Jackson, Brian

    2013-01-01

    A re-purposed Kepler mission could continue the search for nearly Earth-sized planets in very short-period (< 1 day) orbits. Recent surveys of the Kepler data already available have revealed at least a dozen such planetary candidates, and a more complete and focused survey is likely to reveal more. Given the planets' short orbital periods, building the requisite signal-to-noise to detect the candidates by stacking multiple transits requires a much shorter observational baseline than for longer-period planets, and the transits are likely more robust against the much larger instrumental variations anticipated for the modified Kepler pointing capabilities. Searching for these unusual planets will also leverage the Kepler mission's already considerable expertise in planetary transit detection and analysis. These candidates may represent an entirely new class of planet. They may also provide unprecedented insights into planet formation and evolution and sensitive probes for planet-star interactions and the stel...

  15. Ultra-short-period Planets in K2 with Companions: A Double Transiting System for EPIC 220674823

    Science.gov (United States)

    Adams, Elisabeth R.; Jackson, Brian; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Duev, Dmitry A.; Jensen-Clem, Rebecca; Salama, Maïssa; Ziegler, Carl; Baranec, Christoph; Kulkarni, Shrinivas; Law, Nicholas M.; Riddle, Reed

    2017-02-01

    Two transiting planets have been identified orbiting K2 target EPIC 220674823. One object is an ultra-short-period planet (USP) with a period of just 0.57 days (13.7 hr), while the other has a period of 13.3 days. Both planets are small, with the former having a radius of {R}{{p}1}=1.5 {R}\\oplus and the latter {R}{{p}2}=2.5 {R}\\oplus . Follow-up observations, including radial velocity (with uncertainties of 110 m s‑1) and high-resolution adaptive optics imagery, show no signs of stellar companions. EPIC 220674823 is the 12th confirmed or validated planetary system in which a USP (i.e., having an orbital period less than 1 day) is accompanied by at least one additional planet, suggesting that such systems may be common and must be accounted for in models for the formation and evolution of such extreme systems.

  16. SHORT-PERIOD g-MODE PULSATIONS IN LOW-MASS WHITE DWARFS TRIGGERED BY H-SHELL BURNING

    Energy Technology Data Exchange (ETDEWEB)

    Córsico, A. H.; Althaus, L. G., E-mail: acorsico@fcaglp.unlp.edu.ar [Grupo de Evolución Estelar y Pulsaciones, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata (Argentina)

    2014-09-20

    The detection of pulsations in white dwarfs with low mass offers the possibility of probing their internal structures through asteroseismology and placing constraints on the binary evolutionary processes involved in their formation. In this Letter, we assess the impact of stable H burning on the pulsational stability properties of low-mass He-core white dwarf models resulting from binary star evolutionary calculations. We found that besides a dense spectrum of unstable radial modes and nonradial g and p modes driven by the κ mechanism due to the partial ionization of H in the stellar envelope, some unstable g modes with short pulsation periods are also powered by H burning via the ε mechanism of mode driving. This is the first time that ε destabilized modes are found in models representative of cool white dwarf stars. The short periods recently detected in the pulsating low-mass white dwarf SDSS J111215.82+111745.0 could constitute the first evidence of the existence of stable H burning in these stars, in particular in the so-called extremely low-mass white dwarfs.

  17. Fourier analysis of short-period SMC Cepheids: A comparison with Galactic Cepheids

    Science.gov (United States)

    Buchler, J. Robert; Moskalik, Pawel

    1994-12-01

    A Fourier analysis has been made of the Small Magellanic Cloud (SMC) classical Cepheid data of Smith et al. It is shown that the grouping into fundamental and first overtone pulsators, implied by the period-luminosity diagram, survives when the Fourier coefficients are plotted versus period. A comparison with the Galactic Cepheid data corroborates the existing evidence that the short period Galactic s-Cepheids are indeed first overtone pulsators. The only long period overtone Cepheid in the sample that is reliably covered (P = 3.49 d) also conforms with the corresponding s-Cepheids. On the other hand, the hypothesis of Gieren et al. that the long period s-Cepheids are fundamental pulsators is refuted. The data show systematic differences between the SMC Cepheids and their Galactic counterparts, differences that are of theoretical interest. The need for a further observational effort devoted to SMC and to Large Magellanic cloud (LMC) Cepheids is stressed.

  18. Effect of short-term subaerial exposure on the cauliflower coral, Pocillopora damicornis, during a simulated extreme low-tide event

    Science.gov (United States)

    Castrillón-Cifuentes, Ana Lucia; Lozano-Cortés, Diego F.; Zapata, Fernando A.

    2017-06-01

    There is increased interest in understanding how stress reduces coral resistance to disturbances and how acclimatization increases the ability of corals to resist future stress. Most extreme low tides at Gorgona Island, which expose reef flats to air, do not appear to negatively affect corals because corals usually do not undergo lethal bleaching during such events. However, coral physiology and fitness may be impacted by this phenomenon. The aim of this study was to evaluate whether corals exposed to air have modified biological functions to resist bleaching. To test this, an extreme low-tide event was simulated in the field. Colonies of Pocillopora damicornis were exposed to air for 15 or 40 min over the course of one, two, or three consecutive days. This procedure was repeated for one to three months. Colonies of P. damicornis exposed to air had reduced fecundity, decreased zooxanthellae density, and changed color from darker to lighter. However, the growth rate of exposed corals was similar to that of non-exposed colonies. We conclude that short periods of subaerial exposure during extreme low tides are not lethal to P. damicornis, but negatively affect sexual reproduction, which might have deleterious effects at the population level. The periodic occurrence of extreme low tides in the tropical eastern Pacific may be one factor responsible for the high rate of asexual reproduction (e.g., fragmentation) in pocilloporid corals of this region.

  19. Effect of short-term subaerial exposure on the cauliflower coral, Pocillopora damicornis, during a simulated extreme low-tide event

    KAUST Repository

    Castrillón-Cifuentes, Ana Lucia

    2017-02-06

    There is increased interest in understanding how stress reduces coral resistance to disturbances and how acclimatization increases the ability of corals to resist future stress. Most extreme low tides at Gorgona Island, which expose reef flats to air, do not appear to negatively affect corals because corals usually do not undergo lethal bleaching during such events. However, coral physiology and fitness may be impacted by this phenomenon. The aim of this study was to evaluate whether corals exposed to air have modified biological functions to resist bleaching. To test this, an extreme low-tide event was simulated in the field. Colonies of Pocillopora damicornis were exposed to air for 15 or 40 min over the course of one, two, or three consecutive days. This procedure was repeated for one to three months. Colonies of P. damicornis exposed to air had reduced fecundity, decreased zooxanthellae density, and changed color from darker to lighter. However, the growth rate of exposed corals was similar to that of non-exposed colonies. We conclude that short periods of subaerial exposure during extreme low tides are not lethal to P. damicornis, but negatively affect sexual reproduction, which might have deleterious effects at the population level. The periodic occurrence of extreme low tides in the tropical eastern Pacific may be one factor responsible for the high rate of asexual reproduction (e.g., fragmentation) in pocilloporid corals of this region.

  20. Extremely asymmetrical scattering of electromagnetic waves in gradually varying periodic arrays

    CERN Document Server

    Gramotnev, D K

    1999-01-01

    This paper analyses theoretically and numerically the effect of varying grating amplitude on the extremely asymmetrical scattering (EAS) of bulk and guided optical modes in non-uniform strip-like periodic Bragg arrays with stepwise and gradual variations in the grating amplitude across the array. A recently developed new approach based on allowance for the diffractional divergence of the scattered wave is used for this analysis. It is demonstrated that gradual variations in magnitude of the grating amplitude may change the pattern of EAS noticeably but not radically. On the other hand, phase variations in the grating may result in a radically new type of Bragg scattering - double-resonant EAS (DEAS). In this case, a combination of two strong simultaneous resonances (one with respect to frequency, and another with respect to the phase variation) is predicted to take place in non-uniform arrays with a step-like phase and gradual magnitude variations of the grating amplitude. The tolerances of EAS and DEAS to sm...

  1. Short-term cropland responses to temperature extreme events during late winter

    Directory of Open Access Journals (Sweden)

    G. De Simon

    2013-04-01

    Full Text Available In recent years, several studies have focused on terrestrial ecosystem response to extreme events. Most of this research has been conducted in natural ecosystems, but few have considered agro-ecosystems. In this study, we investigated the impact of a manipulated warmer or cooler late winter-early spring on the carbon budget and final harvest of a soybean crop (Glycine max (L. Merr.. Soil temperature was altered by manipulating soil albedo by covering the soil surface with a layer of inert silica gravel. We tested three treatments: cooling (Co, warming (W, mix (M and control (C. An automated system continuously measured soil heterotrophic respiration (Rh, soil temperature profiles, and soil water content across the entire year in each plot. Phenological phases were periodically assessed and final harvest was measured in each plot. Results showed that treatments had only a transient effect on daily Rh rates which did not result in a total annual carbon budget significantly different from control, even though cooling showed a significant reduction in final harvest. We also observed anticipation in seed germination in both W and M treatments and a delay in germination for Co. Moreover, plant density and growth increased in W and M and decreased in Co.

  2. Uncertainties of the 50-year wind from short time series using generalized extreme value distribution and generalized Pareto distribution

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo; Mann, Jakob; Rathmann, Ole

    2015-01-01

    as a guideline for applying GEVD and GPD to wind time series of limited length. The data analysis shows that, with reasonable choice of relevant parameters, GEVD and GPD give consistent estimates of the return winds. For GEVD, the base period should be chosen in accordance with the occurrence of the extreme wind......This study examines the various sources to the uncertainties in the application of two widely used extreme value distribution functions, the generalized extreme value distribution (GEVD) and the generalized Pareto distribution (GPD). The study is done through the analysis of measurements from...

  3. Coherent phonon transport in short-period two-dimensional superlattices of graphene and boron nitride

    Science.gov (United States)

    da Silva, Carlos; Saiz, Fernan; Romero, David A.; Amon, Cristina H.

    2016-03-01

    Promoting coherent transport of phonons at material interfaces is a promising strategy for controlling thermal transport in nanostructures and an alternative to traditional methods based on structural defects. Coherent transport is particularly relevant in short-period heterostructures with smooth interfaces and long-wavelength heat-carrying phonons, such as two-dimensional superlattices of graphene and boron nitride. In this work, we predict phonon properties and thermal conductivities in these superlattices using a normal mode decomposition approach. We study the variation of the frequency dependence of these properties with the periodicity and interface configuration (zigzag and armchair) for superlattices with period lengths within the coherent regime. Our results showed that the thermal conductivity decreases significantly from the first period length (0.44 nm) to the second period length (0.87 nm), 13% across the interfaces and 16% along the interfaces. For greater periods, the conductivity across the interfaces continues decreasing at a smaller rate of 11 W/mK per period length increase (0.43 nm), driven by changes in the phonon group velocities (coherent effects). In contrast, the conductivity along the interfaces slightly recovers at a rate of 2 W/mK per period, driven by changes in the phonon relaxation times (diffusive effects). By changing the interface configuration from armchair to zigzag, the conductivities for all period lengths increase by approximately 7% across the interfaces and 19% along the interfaces.

  4. Main periodicities of the minimum extreme temperature of three stations near the Mexican Pacific coast

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, B.; Maravilla, D. [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: blanca@geofisica.unam.mx; Jauregui, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2006-01-15

    Three minimum extreme temperature series from meteorological stations located in or near the Mexican Pacific coast, Acapulco, Comitan and Manzanillo, are spectrally analyzed. The series cover a period from 1941 to 1981. The spectral analysis indicates that a significant quasiquinquenial periodicity ({approx}5 years) is present in Comitan and Manzanillo, even more, Acapulco also shows a frequency {approx} 5 year if the uncertainties are taken into account. This spectral peak can be considered either as related to solar activity or to strong El Nino events. The remaining periodicities can be associated to meteorological phenomena like El Nino and the quasi-biennial oscillation or to some solar activity phenomena. Furthermore, the behavior deduced from a coherence spectral analysis between the temperature and the Southern Oscillation Index, considered as a proxy of El Nino, and sunspot number, considered as a proxy of solar activity, indicates that the stations closer to the ocean might be more influenced by El Nino than by solar activity, while the station inland has both influences. [Spanish] Se analizan espectralmente tres series de temperatura minima extrema de las estaciones meteorologicas localizadas en o cerca de la costa del Pacifico mexicano: Acapulco, Comitan y Manzanillo. Las series tienen una longitud de 41 anos, abarcando los anos de 1941 a 1981. Del analisis se observa que existe una periodicidad cuasi-quinquenal significativa en los espectros de Comitan y Manzanillo, Acapulco tambien presenta una periodicidad cercana a los 5 anos si se toman en cuenta las incertidumbres. Este pico espectral pudiera estar relacionado con eventos fuertes de El Nino o bien con la actividad solar. Las otras periodicidades encontradas tal vez estan asociadas con fenomenos tales como la oscilacion cuasi-bienal o El Nino, o bien con fenomenos solares. Aunado a esto, los resultados del analisis de coherencia espectral entre la temperatura y la Oscilacion del Sur, considerada un

  5. Study on the Geomagnetic Short Period Variations of the Northwestern Yunnan

    Science.gov (United States)

    Yuan, Y.; Li, Q.; Cai, J.

    2015-12-01

    The Northwestern Yunnan is located in the interaction area between the Eurasian plate and the India plate. This area has been the ideal place for the research of continental dynamics and the prediction for risk region of strong earthquake for its complex tectonic environment and frequent seismic activity. Therefore the study on the geomagnetic short period variations is of great significance in the exploration of deep electrical structure, analysis of the seismic origin and deep geodynamics in the Northwestern Yunnan of China . This paper is based on the geomagnetic data from the magnetometer array with 8 sites built in the northwestern Yunnan to explore the deep electrical structure by the method of geomagnetic depth sounding. Firstly, we selected a total of 183 geomagnetic short period events at the range of 6min to 120min period. And we found a north northwest dividing line, of which two sides has the opposite value in the vertical component variation amplitude, which indicates the obvious conductivity anomaly underground. Secondly, the contour maps of the ratio of vertical component and horizontal component variation amplitude ΔZ/ΔH in different periods reflects the changes of a high conductivity belt's direction and position. In addition, the induction arrows maps within the period of 2 - 256min also shows that on the two sides of the dividing line the induction vectors deviate from each other, and the amplitude and direction of vectors varies with periods regularly. In the light of this, we infer that a high conductivity belt probably exists, which stretches from the deep crust to uppermost mantle and changes with depth constantly with the reference of magnetotelluric sounding. In the end of this paper, the staggered grid finite difference method is used to model the simplified three-dimensional high conductivity anomaly, and the result shows magnetic field distributions are consistent with the observed geomagnetic short period variations characteristics in

  6. A population of short-period variable quasars from PTF as supermassive black hole binary candidates

    Science.gov (United States)

    Charisi, M.; Bartos, I.; Haiman, Z.; Price-Whelan, A. M.; Graham, M. J.; Bellm, E. C.; Laher, R. R.; Márka, S.

    2016-12-01

    Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circum-binary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35 383 spectroscopically confirmed quasars in the photometric data base of the Palomar Transient Factory (PTF). We analysed Lomb-Scargle periodograms and assessed the significance of our findings by modelling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PTF and the Catalina Real-Time Transient Survey. Assuming that the observed periods correspond to the redshifted orbital periods of SMBHBs, we conclude that our findings are consistent with a population of unequal-mass SMBHBs, with a typical mass ratio as low as q ≡ M2/M1 ≈ 0.01.

  7. VizieR Online Data Catalog: SuperWASP short period eclipsing binaries (Norton+, 2011)

    Science.gov (United States)

    Norton, A. J.; Payne, S. G.; Evans, T.; West, R. G.; Wheatley, P. J.; Anderson, D. R.; Barros, S. C. C.; Butters, O. W.; Collier, Cameron A.; Christian, D. J.; Enoch, B.; Faedi, F.; Haswell, C. A.; Hellier, C.; Holmes, S.; Horne, K. D.; Kane, S. R.; Lister, T. A.; Maxted, P. F. L.; Parley, N.; Pollacco, D.; Simpson, E. K.; Skillen, I.; Smalley, B.; Southworth, J.; Street, R. A.

    2011-10-01

    The catalog contains the list of 53 candidate short period eclipsing binaries. The SuperWASP ID encodes the J2000 position of the star as 1SWASP Jhhmmss.ss+/-ddmmss.s. In the table we list the RA and Dec of each object extracted from the SuperWASP ID. We also list the orbital period in days, the peak magnitude of the object in the SuperWASP V-band, along with the depths (in magnitudes) of the primary and secondary minima. (1 data file).

  8. Modification of magnetic signals of short-period pulsations by the ionosphere

    OpenAIRE

    Shigeru, Fujita

    1985-01-01

    The transmission, mode conversion, and reflection of HM-waves associated with short-period geomagnetic pulsations through and by the ionosphere are comparatively examined for three different model cases, bearing in mind the localized injection of the shear Alfven wave at high latitude and the consequent horizontal spread of disturbances to low-latitude regions through the ducted propagation in the upper ionosphere. In the first model case composed of two semiinfinite layers (the magnetosphere...

  9. Hydrostatic pressure and strain effects in short period InN/GaN superlattices

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede;

    2012-01-01

    The electronic structures of short-period pseudomorphically grown superlattices (SLs) of the form mInN/nGaN are calculated and the band gap variation with the well and the barrier thicknesses is discussed including hydrostatic pressure effects. The calculated band gap shows a strong dependence on...... strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....

  10. Short-rotation woody-crops program. Quarterly progress report for period ending August 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.; Ranney, J.W.

    1982-04-01

    Progress of twenty-one projects in the Short Rotation Woody Crops Program is summarized for the period June 1 through August 31, 1981. Individual quarterly reports included from each of the projects discuss accomplishments within specific project objectives and identify recent papers and publications resulting from the research. The major program activities are species screening and genetic selection, stand establishment and cultural treatment, and harvest, collection, transportation, and storage.

  11. Piezoelectrics by Design: A Route through Short-period Perovskite Superlattices

    CERN Document Server

    Das, Hena; Saha-Dasgupta, T

    2010-01-01

    Using first-principles density functional theory, we study piezoelectricity in short-period superlattices made with combination of ferroelectric and paraelectric components and exhibiting polar discontinuities. We show that piezoelectric response of such a superlattice can be tuned both in terms of sign and magnitude with a choice of its components. As these superlattices with nonswitchable polarization do not undergo ferroelectric transitions, we predict them to exhibit a robust piezoelectric response with weaker temperature dependence compared to their bulk counterparts.

  12. Short-rotation woody-crops program. Quarterly progress report for period ending May 31, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.; Ranney, J.W.

    1982-04-01

    Progress of twenty projects in the Short Rotation Woody Crops Program is summarized for the period March 1 through May 31, 1981. Individual quarterly reports included from each of the projects discuss accomplishments within specific project objectives and identify recent papers and publications resulting from the research. The major project activities are species screening and genetic selection, stand establishment and cultural treatment, and harvest, collection, transportation, and storage.

  13. Phenological Response of an Arizona Dryland Forest to Short-Term Climatic Extremes

    Directory of Open Access Journals (Sweden)

    Jessica Walker

    2015-08-01

    Full Text Available Baseline information about dryland forest phenology is necessary to accurately anticipate future ecosystem shifts. The overarching goal of our study was to investigate the variability of vegetation phenology across a dryland forest landscape in response to climate alterations. We analyzed the influence of site characteristics and climatic conditions on the phenological patterns of an Arizona, USA, ponderosa pine (Pinus ponderosa forest during a five-year period (2005 to 2009 that encompassed extreme wet and dry precipitation regimes. We assembled 80 synthetic Landsat images by applying the spatial and temporal adaptive reflectance fusion method (STARFM to 500 m MODIS and 30 m Landsat-5 Thematic Mapper (TM data. We tested relationships between site characteristics and the timing of peak Normalized Difference Vegetation Index (NDVI to assess the effect of climatic stress on the green-up of individual pixels during or after the summer monsoon. Our results show that drought-induced stress led to a fragmented phenological response that was highly dependent on microsite parameters, as both the spatial autocorrelation of peak timing and the number of significant site variables increased during the drought year. Pixels at lower elevations and with higher proportions of herbaceous vegetation were more likely to exhibit dynamic responses to changes in precipitation conditions. Our study demonstrates the complexity of responses within dryland forest ecosystems and highlights the need for standardized monitoring of phenology trends in these areas. The spatial and temporal variability of phenological signals may provide a quantitative solution to the problem of how to evaluate dryland land surface trends across time.

  14. The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

    Science.gov (United States)

    da Costa, Diogo Ricardo; Hansen, Matheus; Guarise, Gustavo; Medrano-T, Rene O.; Leonel, Edson D.

    2016-04-01

    We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems.

  15. Seismic tomography of Yunnan region using short-period surface wave phase velocity

    Institute of Scientific and Technical Information of China (English)

    何正勤; 苏伟; 叶太兰

    2004-01-01

    The data of short-period (1~18 s) surface waves recorded by 23 stations belonging to the digital seismic network of Yunnan Province of China are used in this paper. From these data, the dispersion curves of phase velocities of the fundamental mode Rayleigh wave along 209 paths are determined by using the two-station narrowband filtering cross-correlation method.Adopting tomography method, the distribution maps of phase velocities at various periods in Yunnan region are inverted. The maps of phase velocities on profiles along 24°N, 25°N, 26°N, 27°N and 100.5°E and the distribution maps of phase velocities at 3 periods in the study region are given. The results show that the phase velocity distribution in Yunnan region has strong variations in horizontal direction, and the phase velocity distribution in short-period range is closely related to the thickness of sedimentary layers in the shallow crust. The phase velocity in southern part of the Sichuan-Yunnan rhombic block encircled by the Honghe fault and Xiaojiang fault is obviously lower than that in surrounding areas. The epicentral locations of strong earthquakes in Yunnan region are mainly distributed in transitional zones between low and high phase velocities.

  16. Medical and psychosocial implications of adolescent extreme obesity – acceptance and effects of structured care, short: Youth with Extreme Obesity Study (YES)

    Science.gov (United States)

    2013-01-01

    Background Prevalence rates of overweight and obesity have increased in German children and adolescents in the last three decades. Adolescents with extreme obesity represent a distinct risk group. On the basis of data obtained by the German Child and Youth Survey (KiGGS) and the German district military offices we estimate that the group of extremely obese adolescents (BMI ≥ 35 kg/m2) currently encompasses approximately 200.000 adolescents aged 14 to 21 yrs. Conventional approaches focusing on weight reduction have largely proven futile for them. In addition, only a small percentage of adolescents with extreme obesity seek actively treatment for obesity while contributing disproportionately strong to health care costs. Because of somatic and psychiatric co-morbidities and social problems adolescents with extreme obesity require special attention within the medical care system. We have initiated the project “Medical and psychosocial implications of adolescents with extreme obesity - acceptance and effects of structured care, short: ‘Youths with Extreme Obesity Study (YES)’”, which aims at improving the medical care and social support structures for youths with extreme obesity in Germany. Methods/Design We focus on identification of these subjects (baseline examination) and their acceptance of diagnostic and subsequent treatment procedures. In a randomized controlled trial (RCT) we will investigate the effectiveness of a low key group intervention not focusing on weight loss but aimed at the provision of obesity related information, alleviation of social isolation, school and vocational integration and improvement of self-esteem in comparison to a control group treated in a conventional way with focus on weight loss. Interested individuals who fulfill current recommended criteria for weight loss surgery will be provided with a structured preparation and follow-up programs. All subjects will be monitored within a long-term observational study to

  17. Short-period InAs/GaSb superlattices for mid-infrared photodetectors

    Energy Technology Data Exchange (ETDEWEB)

    Haugan, H.J.; Szmulowicz, F.; Brown, G.J.; Munshi, S.R. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States); Ullrich, B. [Department of Physics and Astronomy, Bowling Green State University, Ohio 45433 (United States); Wickett, J.C.; Stokes, D.W. [Department of Physics, University of Houston, Texas 77204 (United States)

    2007-04-15

    Using a newly developed envelope function approximation model that includes interface effects, several InAs/GaSb type-II superlattices (SLs) were designed for uncooled mid-infrared detector applications. The 4 micron cutoff could be achieved with several SL designs. Superlattices with shorter periods have larger intervalence band separations than larger-ones, which could increase the optical signal and reduce the detector noise, thus making room temperature operation possible. To test these possibilities, several short-period SLs were grown by molecular-beam epitaxy and their optical properties with reducing SL period were studied by band-edge absorption, photoconductivity and photoluminescence measurements. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Stimulus-response characteristics of motor evoked potentials and silent periods in proximal and distal upper-extremity muscles.

    NARCIS (Netherlands)

    Kuijk, A.A. van; Anker, L.C.; Pasman, J.W.; Hendriks, J.C.M.; Elswijk, G.A.F. van; Geurts, A.C.H.

    2009-01-01

    OBJECTIVE: To compare stimulus-response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles. METHODS: Stimulus-response curves of MEPs and SPs were obtained from the biceps bra

  19. Stimulus-response characteristics of motor evoked potentials and silent periods in proximal and distal upper-extremity muscles.

    NARCIS (Netherlands)

    Kuijk, A.A. van; Anker, L.C.; Pasman, J.W.; Hendriks, J.C.M.; Elswijk, G.A.F. van; Geurts, A.C.H.

    2009-01-01

    OBJECTIVE: To compare stimulus-response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles. METHODS: Stimulus-response curves of MEPs and SPs were obtained from the biceps bra

  20. Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

    DEFF Research Database (Denmark)

    Babraj, John A; Vollaard, Niels B J; Keast, Cameron

    2009-01-01

    BACKGROUND: Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT) has recently been demonstrated to produce improvements to aerobic function, but i...

  1. Facing the Future: Effects of Short-Term Climate Extremes on Isoprene-Emitting and Nonemitting Poplar1

    Science.gov (United States)

    Vanzo, Elisa; Jud, Werner; Li, Ziru; Albert, Andreas; Domagalska, Malgorzata A.; Ghirardo, Andrea; Niederbacher, Bishu; Frenzel, Juliane; Beemster, Gerrit T.S.; Asard, Han; Rennenberg, Heinz; Sharkey, Thomas D.; Hansel, Armin; Schnitzler, Jörg-Peter

    2015-01-01

    Isoprene emissions from poplar (Populus spp.) plantations can influence atmospheric chemistry and regional climate. These emissions respond strongly to temperature, [CO2], and drought, but the superimposed effect of these three climate change factors are, for the most part, unknown. Performing predicted climate change scenario simulations (periodic and chronic heat and drought spells [HDSs] applied under elevated [CO2]), we analyzed volatile organic compound emissions, photosynthetic performance, leaf growth, and overall carbon (C) gain of poplar genotypes emitting (IE) and nonemitting (NE) isoprene. We aimed (1) to evaluate the proposed beneficial effect of isoprene emission on plant stress mitigation and recovery capacity and (2) to estimate the cumulative net C gain under the projected future climate. During HDSs, the chloroplastidic electron transport rate of NE plants became impaired, while IE plants maintained high values similar to unstressed controls. During recovery from HDS episodes, IE plants reached higher daily net CO2 assimilation rates compared with NE genotypes. Irrespective of the genotype, plants undergoing chronic HDSs showed the lowest cumulative C gain. Under control conditions simulating ambient [CO2], the C gain was lower in the IE plants than in the NE plants. In summary, the data on the overall C gain and plant growth suggest that the beneficial function of isoprene emission in poplar might be of minor importance to mitigate predicted short-term climate extremes under elevated [CO2]. Moreover, we demonstrate that an analysis of the canopy-scale dynamics of isoprene emission and photosynthetic performance under multiple stresses is essential to understand the overall performance under proposed future conditions. PMID:26162427

  2. Facing the Future: Effects of Short-Term Climate Extremes on Isoprene-Emitting and Nonemitting Poplar.

    Science.gov (United States)

    Vanzo, Elisa; Jud, Werner; Li, Ziru; Albert, Andreas; Domagalska, Malgorzata A; Ghirardo, Andrea; Niederbacher, Bishu; Frenzel, Juliane; Beemster, Gerrit T S; Asard, Han; Rennenberg, Heinz; Sharkey, Thomas D; Hansel, Armin; Schnitzler, Jörg-Peter

    2015-09-01

    Isoprene emissions from poplar (Populus spp.) plantations can influence atmospheric chemistry and regional climate. These emissions respond strongly to temperature, [CO2], and drought, but the superimposed effect of these three climate change factors are, for the most part, unknown. Performing predicted climate change scenario simulations (periodic and chronic heat and drought spells [HDSs] applied under elevated [CO2]), we analyzed volatile organic compound emissions, photosynthetic performance, leaf growth, and overall carbon (C) gain of poplar genotypes emitting (IE) and nonemitting (NE) isoprene. We aimed (1) to evaluate the proposed beneficial effect of isoprene emission on plant stress mitigation and recovery capacity and (2) to estimate the cumulative net C gain under the projected future climate. During HDSs, the chloroplastidic electron transport rate of NE plants became impaired, while IE plants maintained high values similar to unstressed controls. During recovery from HDS episodes, IE plants reached higher daily net CO2 assimilation rates compared with NE genotypes. Irrespective of the genotype, plants undergoing chronic HDSs showed the lowest cumulative C gain. Under control conditions simulating ambient [CO2], the C gain was lower in the IE plants than in the NE plants. In summary, the data on the overall C gain and plant growth suggest that the beneficial function of isoprene emission in poplar might be of minor importance to mitigate predicted short-term climate extremes under elevated [CO2]. Moreover, we demonstrate that an analysis of the canopy-scale dynamics of isoprene emission and photosynthetic performance under multiple stresses is essential to understand the overall performance under proposed future conditions.

  3. PLANET HUNTERS: ASSESSING THE KEPLER INVENTORY OF SHORT-PERIOD PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Schwamb, Megan E. [Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520 (United States); Lintott, Chris J.; Lynn, Stuart; Smith, Arfon M.; Simpson, Robert J. [Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Fischer, Debra A.; Giguere, Matthew J.; Brewer, John M. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Parrish, Michael [Adler Planetarium, 1300 S. Lake Shore Drive, Chicago, IL 60605 (United States); Schawinski, Kevin, E-mail: megan.schwamb@yale.edu [Department of Physics, Yale University, New Haven, CT 06511 (United States)

    2012-08-01

    We present the results from a search of data from the first 33.5 days of the Kepler science mission (Quarter 1) for exoplanet transits by the Planet Hunters citizen science project. Planet Hunters enlists members of the general public to visually identify transits in the publicly released Kepler light curves via the World Wide Web. Over 24,000 volunteers reviewed the Kepler Quarter 1 data set. We examine the abundance of {>=}2 R{sub Circled-Plus} planets on short-period (<15 days) orbits based on Planet Hunters detections. We present these results along with an analysis of the detection efficiency of human classifiers to identify planetary transits including a comparison to the Kepler inventory of planet candidates. Although performance drops rapidly for smaller radii, {>=}4 R{sub Circled-Plus} Planet Hunters {>=}85% efficient at identifying transit signals for planets with periods less than 15 days for the Kepler sample of target stars. Our high efficiency rate for simulated transits along with recovery of the majority of Kepler {>=}4 R{sub Circled-Plus} planets suggests that the Kepler inventory of {>=}4 R{sub Circled-Plus} short-period planets is nearly complete.

  4. Absence of a Metallicity Effect for Ultra-short-period Planets

    Science.gov (United States)

    Winn, Joshua N.; Sanchis-Ojeda, Roberto; Rogers, Leslie; Petigura, Erik A.; Howard, Andrew W.; Isaacson, Howard; Marcy, Geoffrey W.; Schlaufman, Kevin C.; Cargile, Phillip; Hebb, Leslie

    2017-08-01

    Ultra-short-period (USP) planets are a newly recognized class of planets with periods shorter than one day and radii smaller than about 2 R ⊕. It has been proposed that USP planets are the solid cores of hot Jupiters that have lost their gaseous envelopes due to photo-evaporation or Roche lobe overflow. We test this hypothesis by asking whether USP planets are associated with metal-rich stars, as has long been observed for hot Jupiters. We find the metallicity distributions of USP-planet and hot-Jupiter hosts to be significantly different (p = 3 × 10-4) based on Keck spectroscopy of Kepler stars. Evidently, the sample of USP planets is not dominated by the evaporated cores of hot Jupiters. The metallicity distribution of stars with USP planets is indistinguishable from that of stars with short-period planets with sizes between 2 and 4 R ⊕. Thus, it remains possible that the USP planets are the solid cores of formerly gaseous planets that are smaller than Neptune. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted by NASA, the University of California, the California Institute of Technology, and the University of Hawaii.

  5. The role of extreme orbits in the global organization of periodic regions in parameter space for one dimensional maps

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Diogo Ricardo da, E-mail: diogo_cost@hotmail.com [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Hansen, Matheus [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Instituto de Física, Univ. São Paulo, Rua do Matão, Cidade Universitária, 05314-970, São Paulo – SP (Brazil); Guarise, Gustavo [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Medrano-T, Rene O. [Departamento de Ciências Exatas e da Terra, UNIFESP – Universidade Federal de São Paulo, Rua São Nicolau, 210, Centro, 09913-030, Diadema, SP (Brazil); Department of Mathematics, Imperial College London, London SW7 2AZ (United Kingdom); Leonel, Edson D. [Departamento de Física, UNESP – Universidade Estadual Paulista, Av. 24A, 1515, Bela Vista, 13506-900, Rio Claro, SP (Brazil); Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy)

    2016-04-22

    We show that extreme orbits, trajectories that connect local maximum and minimum values of one dimensional maps, play a major role in the parameter space of dissipative systems dictating the organization for the windows of periodicity, hence producing sets of shrimp-like structures. Here we solve three fundamental problems regarding the distribution of these sets and give: (i) their precise localization in the parameter space, even for sets of very high periods; (ii) their local and global distributions along cascades; and (iii) the association of these cascades to complicate sets of periodicity. The extreme orbits are proved to be a powerful indicator to investigate the organization of windows of periodicity in parameter planes. As applications of the theory, we obtain some results for the circle map and perturbed logistic map. The formalism presented here can be extended to many other different nonlinear and dissipative systems. - Highlights: • Extreme orbits and the organization of periodic regions in parameter space. • One-dimensional dissipative mappings. • The circle map and also a time perturbed logistic map were studied.

  6. Dynamics of the Bingham Canyon mine landslides from long-period and short-period seismic signal analysis

    Science.gov (United States)

    Hibert, C.; Ekstrom, G.; Stark, C. P.

    2013-12-01

    On April 10, 2013, one of the largest landslides observed in North America occurred at the Bingham Canyon copper mine near Salt Lake City, Utah. Seismic waves recorded by the Global Seismographic Network suggest that two major slope failures occurred: at 03:31UT and at 05:06UT with long-period surface-wave magnitudes of Msw~5.1 and Msw~4.9 respectively. The combined debris of these landslides has been estimated at 150 million tonnes. We used long-period surface wave data to invert for the Landslide Force History (LFH) of each of the two events, allowing us to infer the trajectories of landslide motion and their average dynamic properties [1]. These inferred runout paths are broadly consistent with those deduced from analysis of the landslide scar using air photographs, satellite imagery and differential topographic maps. However, the total mass obtained from the LFH analysis is less consistent: using the observed runout distances for calibration [1], our inversions suggest a total landslide mass 50% less than that reported by the mining company. A further complexity, possibly related, is revealed by analysis of the short-period seismic waves, which indicates that the 05:06UT detection is in fact the composite signal of two distinct landslide seismic sources. Usually, high-frequency (HF, >1Hz) seismic signals generated by landslides are hard to observe because of their strong scattering and attenuation with distance. However, a very dense network of broadband seismic stations exists in the vicinity of the Bingham Canyon mine. Thus, we were able to compare the LFH, long-period and HF seismic signals for both events. Joint analysis of the inverted trajectory and the HF seismic signal recorded at the closest stations shows that, for the first 03:31UT event, a backward movement of the mass center started just after a final burst in the very high-frequency (VHF, >20Hz) signal. After this final burst, a tremor-like signal is observed in the VHF. This tremor-like signal

  7. Parameters of two low-mass contact eclipsing binaries near the short-period limit

    CERN Document Server

    Lohr, M E; Norton, A J; Kolb, U C

    2014-01-01

    The two objects 1SWASP J150822.80-054236.9 and 1SWASP J160156.04+202821.6 were initially detected from their SuperWASP archived light curves as candidate eclipsing binaries with periods close to the short-period cut-off of the orbital period distribution of main sequence binaries, at ~0.2 d. Here, using INT spectroscopic data, we confirm them as double-lined spectroscopic and eclipsing binaries, in contact configuration. Following modelling of their visual light curves and radial velocity curves, we determine their component and system parameters to precisions between ~2 and 11%. The former system contains 1.07 and 0.55 M_sun components, with radii of 0.90 and 0.68 R_sun respectively; its primary exhibits pulsations with period 1/6 the orbital period of the system. The latter contains 0.86 and 0.57 M_sun components, with radii of 0.75 and 0.63R_sun respectively.

  8. Automatic interpretation of regional short period seismic signals using CUSUM-SA algorithms

    Science.gov (United States)

    der, Zoltan A.; Shumway, Robert H.

    Several simple methods for the automatic interpretation of short period regional seismogram were tested. Because of the emergent nature of most regional arrivals, the onsets of seismic phases are associated with gradual, rather than sudden, changes in the autoregressive models and mean square amplitudes. We have found that amplitude contrasts between windows containing the seismic phase and the noise (background prior to the arrival) can be enhanced by filtering making use of autoregressive models and thus in the further analysis we utilize only the enhanced amplitude changes for defining onset times.

  9. A modified Lee-Carter model for analysing short-base-period data.

    Science.gov (United States)

    Zhao, Bojuan Barbara

    2012-03-01

    This paper introduces a new modified Lee-Carter model for analysing short-base-period mortality data, for which the original Lee-Carter model produces severely fluctuating predicted age-specific mortality. Approximating the unknown parameters in the modified model by linearized cubic splines and other additive functions, the model can be simplified into a logistic regression when fitted to binomial data. The expected death rate estimated from the modified model is smooth, not only over ages but also over years. The analysis of mortality data in China (2000-08) demonstrates the advantages of the new model over existing models.

  10. On some single-hump solutions of the short-pulse equation and their periodic generalizations

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y.; Williams, F.; Whitaker, N. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-4515 (United States); Kevrekidis, P.G., E-mail: kevrekid@gmail.co [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-4515 (United States); Saxena, A. [Center for Nonlinear Studies and Theoretical Division, MS B262, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Frantzeskakis, D.J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784 (Greece)

    2010-06-28

    In the present work, we consider both localized (e.g. peakon and breather) and extended waveforms (peakon-lattice and breather-lattice, as well as some periodic ones) that arise in the context of the short-pulse equation, as emanating from their sine-Gordon equation analogs. Through direct numerical simulations, we find that the most robust solution is the breather, although some of the single-hump variants of the periodic solutions may be preserved upon the time dynamics as well. Multi-peakon, as well as multi-breather and multi-hump profiles more generally are found to be subject to symmetry-breaking instabilities and are, thus, less robust.

  11. Infrared Spectroscopic Observations of the Secondary Stars of Short Period Sub-Gap Cataclysmic Variables

    CERN Document Server

    Hamilton, Ryan T; Tappert, Claus; Howell, Steve B

    2010-01-01

    We present K-band spectroscopy of short period, "sub-gap" cataclysmic variable (CV) systems obtained using ISAAC on the VLT. We show the infrared spectra (IR) for nine systems below the 2-3 hour period gap: V2051 Oph, V436 Cen, EX Hya, VW Hyi, Z Cha, WX Hyi, V893 Sco, RZ Leo, and TY PsA. We are able to clearly detect the secondary star in all but WX Hyi, V893 Sco, and TY PsA. We present the first direct detection of the secondary stars of V2051 Oph, V436 Cen, and determine new spectral classifications for EX Hya, VW Hyi, Z Cha, and RZ Leo. We find that the CO band strengths of all but Z Cha appear normal for their spectral types, in contrast to their longer period cousins above the period gap. This brings the total number of CVs and pre-CVs with moderate resolution (R >~ 1500) IR spectroscopy to sixty-one systems: nineteen pre-CVs, thirty-one non-magnetic systems, and eleven magnetic or partially magnetic systems. We discuss the trends seen in the IR abundance patterns thus far, and highlight a potential link...

  12. Correlation Between Time Change in Modulus of Short-Period Geomagnetic Variation and Seismicity in Taiwan

    Directory of Open Access Journals (Sweden)

    Kuang-Jung Chen

    2007-01-01

    Full Text Available In this study, geomagnetic data of the Lunping observatory from 1993 to 2000 are utilized for computing the amplitude variation of short-period geomagnetic total intensity data, using the complex demodulation method (CD method. In order to compare these time changes with seismicity, earthquakes that occurred within 150 km of Lunping, with magnitude ML greater than 3.0, are located. The total sum of those earthquakes, summed month by month, is correlated with the modulus. After removing seasonal effect, our results show that the modulus of periods 24, 12, and 8 hr reveals a notable change that seems to be related to the total sum of events within the whole study period. One possible precursor is found 6 months prior to the 1999 high seismicity. The modulus for the periods 24, 12, and 8 hr increased gradually from the beginning of 1999 to August 1999. After earthquake occurrence the modulus decreased again to a normal level. We propose that this notable increase might be related to a preparation process for this strong earthquake.

  13. Determination of circulation and short period fluctuation in Ilha Grande Bay (RJ, Brazil

    Directory of Open Access Journals (Sweden)

    Yoshimine Ikeda

    1980-06-01

    Full Text Available A mesosoale study was made of the Ilha Grande area. The local circulation described through -progressive vector diagrams showed a clochwise bottom circulation determined in June 1976, while in the upper 10 m the direction of the flow entering the Ilha Grande Bay was towards the center in the west and towards the Marambaia sandbank in the east side of the Bay. Short periods and amplitude fluctuations were evaluted using power spectral analysis, Fourier and Maximum Entropy Method, which showed that in the upper 10 m predominant periods decrease from 1.1h (A = 6.3cm sec-1 (position = 3C to 1.0h (A = 7.4 cm sec-1 (position = 2D and increase to 5.8h (A = 6.8 cm., sec-1 (position = ID, while at the bottom layer the predominant period increases from 0.4 h (A = 5.0 cm sec-1 (position = 3G to 6.4h (A = 7.0 cm sec-1 (position = 2G and to 4.4h (A = 7.9 cm sec-1 (position = 1G . From the original data it has been possible to determine an "intense pulsation" between 30-70 cm sec-1 in the upper 10 m with about 1.0h period and 10-20 min duration in all the stations.

  14. Inter-hemispheric Comparison of Mesospheric Short-period Gravity Wave Propagation

    Science.gov (United States)

    Nielsen, K.; Taylor, M. J.; Collins, R. L.; Irving, B. K.; Negale, M.; Siskind, D. E.; Eckermann, S. D.; Hoppel, K.; Harvey, V.; Russell, J. M.

    2011-12-01

    Mesospheric short-period (≤1-hr) gravity waves are of great importance for dynamics in the mesosphere-lower thermosphere (MLT) region, and are typically measured by instruments capable of high temporal and/or spatial resolutions such as lidars and airglow imagers. These waves have been studied extensively at low- and mid-latitudes where known wave sources are well established. The results show strong dependence on the background wind and temperature fields, which can act as a barrier prohibiting vertical propagation of the waves, as well as providing a ducted environment in which the waves can travel large horizontal distances. In fact, results show that up to 75% of these waves may exhibit ducted wave motion. Recent airglow imaging measurements over Antarctica have revealed a large number of short-period gravity waves in absence of the prominent wave sources present at lower latitudes. In contrast to results at lower latitudes, very few waves (˜5%) observed over Halley (76°S) exhibited Doppler ducted motion. In this work, we utilize airglow imagery, SABER temperature measurements, together with the Navy's high-altitude numerical weather prediction system, NOGAPS-ALPHA, to investigate propagation conditions (particularly, the role of thermal ducting) over Rothera (68°S). Data acquired from a newly installed airglow imager operating at Poker Flat, Alaska (65°N) and the co-located lidar provide an opportunity to perform an inter-hemispheric comparison of propagation conditions over two polar sites at similar latitudes.

  15. Long-term tidal evolution of short-period planets with companions

    CERN Document Server

    Mardling, Rosemary A

    2007-01-01

    Of the fourteen transiting extrasolar planetary systems for which radii have been measured, at least three appear to be considerably larger than theoretical estimates suggest. It has been proposed by Bodenheimer, Lin & Mardling that undetected companions acting to excite the orbital eccentricity are responsible for these oversized planets, as they find new equilibrium radii in response to being tidally heated. In the case of HD 209458, this hypothesis has been rejected by some authors because there is no sign of such a companion at the 5 m/s level, and because it is difficult to say conclusively that the eccentricity is non-zero. Transit timing analysis [...]. Whether or not a companion is responsible for the large radius of HD 209458b, almost certainly some short-period systems have companions which force their eccentricities to nonzero values. This paper is dedi. to quantifying this effect. The eccentricity of a short-period planet will only be excited as long as its (non-resonant) companion's eccentric...

  16. KELT-16b: A highly irradiated, ultra-short period hot Jupiter nearing tidal disruption

    CERN Document Server

    Oberst, Thomas E; Colón, Knicole D; Angerhausen, Daniel; Bieryla, Allyson; Ngo, Henry; Stevens, Daniel J; Stassun, Keivan G; Gaudi, B Scott; Pepper, Joshua; Penev, Kaloyan; Mawet, Dimitri; Latham, David W; Heintz, Tyler M; Osei, Baffour W; Collins, Karen A; Kielkopf, John F; Visgaitis, Tiffany; Reed, Phillip A; Escamilla, Alejandra; Yazdi, Sormeh; McLeod, Kim K; Lunsford, Leanne T; Spencer, Michelle; Joner, Michael D; Gregorio, Joao; Gaillard, Clement; Matt, Kyle; Dumont, Mary Thea; Stephens, Denise C; Cohen, David H; Jensen, Eric L N; Novati, Sebastiano Calchi; Bozza, Valerio; Labadie-Bartz, Jonathan; Siverd, Robert J; Lund, Michael B; Beatty, Thomas G; Eastman, Jason D; Penny, Matthew T; Manner, Mark; Zambelli, Roberto; Fulton, Benjamin J; DePoy, D L; Marshall, Jennifer L; Pogge, Richard W; Gould, Andrew; Trueblood, Mark; Trueblood, Patricia

    2016-01-01

    We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright ($V = 11.7$) star TYC 2688-1839-1/KELT-16. A global analysis of the system shows KELT-16 to be a F7V star with $T_{\\rm eff} = 6236\\pm54$ K, $\\log{g_\\star} = 4.253_{-0.036}^{+0.031}$, $[Fe/H] = -0.002_{-0.085}^{+0.086}$, $M_\\star = 1.211_{-0.046}^{+0.043} M_\\odot$, and $R_\\star = 1.360_{-0.053}^{+0.064} R_\\odot$. The planet is a relatively high mass inflated gas giant with $M_P = 2.75_{-0.15}^{+0.16} M_J$, $R_P = 1.415_{-0.067}^{+0.084} R_J$, density $\\rho_{P} = 1.20\\pm0.18$ g cm$^{-3}$, surface gravity $\\log{g_{P}} = 3.530_{-0.049}^{+0.042}$, and $T_{eq} = 2453_{-47}^{+55}$ K. The best-fitting linear ephemeris is $T_C = 2457247.24791\\pm0.00019$ BJD$_{TBD}$ and $P = 0.9689951 \\pm 0.0000024$ days. KELT-16b joins WASP-18b, -19b, -43b, -103b, and HATS-18b as the only giant transiting planets with $P < 1$ day. Its ultra-short period and high irradiation make it a benchmark target for atmos...

  17. Evaluation of short-period rainfall estimates from Kalpana-1 satellite using MET software

    Indian Academy of Sciences (India)

    Soma Sen Roy; Subhendu Brata Saha; Hashmi Fatima; S K Roy Bhowmik; P K Kundu

    2012-10-01

    The INSAT Multispectral Rainfall Algorithm (IMSRA) technique for rainfall estimation, has recently been developed to meet the shortcomings of the Global Precipitation Index (GPI) technique of rainfall estimation from the data of geostationary satellites; especially for accurate short period rainfall estimates. This study evaluates the 3-hourly precipitation estimates by this technique as well as the rainfall estimates by the GPI technique using data of the Kalpana-1 satellite, over the Indian region for the south-west monsoon season of 2010 to understand their relative strengths and weaknesses in estimating short period rainfall. The gridded 3 hourly accumulated TRMM satellite (3B42 V6 product or TMPA product) and surface raingauge data for stations over the Indian region for the same period is used as the standard measure of rainfall estimates. The Method for Object-based Diagnostic Evaluation (MODE) utility of the METv3.0 software, has been used for the evaluation purpose. The results show that the new IMSRA technique is closer to the TMPA rainfall estimate, in terms of areal spread, geometric shape and location of rainfall areas, as compared to the GPI technique. The overlap of matching rainfall areas with respect to TMPA rainfall patches is also higher for the IMSRA estimates as compared to the GPI values. However, both satellite rainfall estimates are observed to be generally higher compared to the TMPA measurements. However, the values for the highest 10% of the rainfall rates in any rainfall patch, is generally higher for rainfall measured by the IMSRA technique, as compared to the estimates by the GPI technique. This may partly be due to the capping maximum limit of 3 mm/hr for rainfall measured by the GPI technique limits the total 3-hour accumulation to 9 mm even during heavy rainfall episodes. This is not so with IMSRA technique, which has no such limiting value. However, this general overestimation of the rainfall amount, measured by both techniques

  18. Time functions of deep earthquakes from broadband and short-period stacks

    Science.gov (United States)

    Houston, H.; Benz, H.M.; Vidale, J.E.

    1998-01-01

    To constrain dynamic source properties of deep earthquakes, we have systematically constructed broadband time functions of deep earthquakes by stacking and scaling teleseismic P waves from U.S. National Seismic Network, TERRAscope, and Berkeley Digital Seismic Network broadband stations. We examined 42 earthquakes with depths from 100 to 660 km that occurred between July 1, 1992 and July 31, 1995. To directly compare time functions, or to group them by size, depth, or region, it is essential to scale them to remove the effect of moment, which varies by more than 3 orders of magnitude for these events. For each event we also computed short-period stacks of P waves recorded by west coast regional arrays. The comparison of broadband with short-period stacks yields a considerable advantage, enabling more reliable measurement of event duration. A more accurate estimate of the duration better constrains the scaling procedure to remove the effect of moment, producing scaled time functions with both correct timing and amplitude. We find only subtle differences in the broadband time-function shape with moment, indicating successful scaling and minimal effects of attenuation at the periods considered here. The average shape of the envelopes of the short-period stacks is very similar to the average broadband time function. The main variations seen with depth are (1) a mild decrease in duration with increasing depth, (2) greater asymmetry in the time functions of intermediate events compared to deep ones, and (3) unexpected complexity and late moment release for events between 350 and 550 km, with seven of the eight events in that depth interval displaying markedly more complicated time functions with more moment release late in the rupture than most events above or below. The first two results are broadly consistent with our previous studies, while the third is reported here for the first time. The greater complexity between 350 and 550 km suggests greater heterogeneity in

  19. A Hybrid Short-Term Traffic Flow Prediction Model Based on Singular Spectrum Analysis and Kernel Extreme Learning Machine.

    Science.gov (United States)

    Shang, Qiang; Lin, Ciyun; Yang, Zhaosheng; Bing, Qichun; Zhou, Xiyang

    2016-01-01

    Short-term traffic flow prediction is one of the most important issues in the field of intelligent transport system (ITS). Because of the uncertainty and nonlinearity, short-term traffic flow prediction is a challenging task. In order to improve the accuracy of short-time traffic flow prediction, a hybrid model (SSA-KELM) is proposed based on singular spectrum analysis (SSA) and kernel extreme learning machine (KELM). SSA is used to filter out the noise of traffic flow time series. Then, the filtered traffic flow data is used to train KELM model, the optimal input form of the proposed model is determined by phase space reconstruction, and parameters of the model are optimized by gravitational search algorithm (GSA). Finally, case validation is carried out using the measured data of an expressway in Xiamen, China. And the SSA-KELM model is compared with several well-known prediction models, including support vector machine, extreme learning machine, and single KLEM model. The experimental results demonstrate that performance of the proposed model is superior to that of the comparison models. Apart from accuracy improvement, the proposed model is more robust.

  20. Short-Term Physical and Mental Health Outcomes for Combat Amputee and Nonamputee Extremity Injury Patients

    Science.gov (United States)

    2012-01-01

    16 5.8 Pulmonary embolism± 27 7.1 11 4.0 *Percentages for amputee group . extremity group (P , 0.05). †P , 0.08. PLS, phantom limb syndrome; ±, deep...consistent with previous research.9,11 Absolute rates of other complications ( phantom limb syndrome, osteomyelitis, and infections) were consistent...Amputees had significantly greater odds of certain mental health disorders including mood, sleep, pain , and postconcussion syndrome. However, ampu- tees

  1. A short-term extremely low frequency electromagnetic field exposure increases circulating leukocyte numbers and affects HPA-axis signaling in mice.

    Science.gov (United States)

    de Kleijn, Stan; Ferwerda, Gerben; Wiese, Michelle; Trentelman, Jos; Cuppen, Jan; Kozicz, Tamas; de Jager, Linda; Hermans, Peter W M; Verburg-van Kemenade, B M Lidy

    2016-10-01

    There is still uncertainty whether extremely low frequency electromagnetic fields (ELF-EMF) can induce health effects like immunomodulation. Despite evidence obtained in vitro, an unambiguous association has not yet been established in vivo. Here, mice were exposed to ELF-EMF for 1, 4, and 24 h/day in a short-term (1 week) and long-term (15 weeks) set-up to investigate whole body effects on the level of stress regulation and immune response. ELF-EMF signal contained multiple frequencies (20-5000 Hz) and a magnetic flux density of 10 μT. After exposure, blood was analyzed for leukocyte numbers (short-term and long-term) and adrenocorticotropic hormone concentration (short-term only). Furthermore, in the short-term experiment, stress-related parameters, corticotropin-releasing hormone, proopiomelanocortin (POMC) and CYP11A1 gene-expression, respectively, were determined in the hypothalamic paraventricular nucleus, pituitary, and adrenal glands. In the short-term but not long-term experiment, leukocyte counts were significantly higher in the 24 h-exposed group compared with controls, mainly represented by increased neutrophils and CD4 ± lymphocytes. POMC expression and plasma adrenocorticotropic hormone were significantly lower compared with unexposed control mice. In conclusion, short-term ELF-EMF exposure may affect hypothalamic-pituitary-adrenal axis activation in mice. Changes in stress hormone release may explain changes in circulating leukocyte numbers and composition. Bioelectromagnetics. 37:433-443, 2016. © 2016 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.

  2. Continuing the Search for Short Period EEB's: The Analysis of HW Persei

    Science.gov (United States)

    McDermith, R. J.; Samec, R. G.; Carrigan, B. J.

    1996-05-01

    In our continuing campaign to obtain light and radial velocity curves of short period eccentric eclipsing binary (EEB) candidates, we have obtained complete UBV observations of the neglected system, HW Persei. They were taken at Lowell Observatory in January 1996. Three new epochs of minimum light have been determined. A preliminary period study, spanning some sixty years of timings (with a 24 year gap), result in the following improved linear ephemeris, 2450097.7836(70) + 0.6348285(4)d X E. A quadratic fit was also calculated. This gave a marginally significant quadratic term of 8(6)X10-11 which translates to a period increase of 5(4)X10-8 d/yr. The U, B, V light curves formed from the present precision observations show that HW Per is a near or shallow contact system. Contrary to earlier reports that HW Per has a displaced secondary eclipse, our secondary eclipse falls at phase 0.5. A complete analysis of the synthetic light curve is presented and discussed. This research was supported by funds from the National Science Foundation.

  3. The Varying Light Curve and Timings of the Ultra-short Period Contact Binary KIC 9532219

    CERN Document Server

    Lee, Jae Woo; Koo, Jae-Rim; Park, Jang-Ho

    2016-01-01

    KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 d that is below the short-period limit ($\\sim$0.22 d) of the period distribution for contact binaries. The {\\it Kepler} light curve of the system exhibits striking light changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of $q$=1.20, an orbital inclination of $i$=66.0 deg, a temperature difference of $\\Delta$ ($T_{1}$--$T_{2}$)=172 K, and a third light of $l_3$=75.9 \\%. To understand the light variations with time, we divided up the light curve into 312 segments and separately analyzed them. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC9532228 between the {\\it Kepler} Quarters and that the variable O'Connell effect originates from the starspot activity on the less massive primary component....

  4. Emission line tomography of the short period cataclysmic variables CC Scl and V2051 Oph

    CERN Document Server

    Longa-Peña, P; Marsh, T

    2014-01-01

    We present time-series spectroscopy of two short period cataclysmic variables, CC Scl and V2051 Oph, to test the efficiency of Doppler tomography-based methods in constraining orbital parameters of evolved cataclysmic variables. We find that the Ca~II triplet lines offer superior diagnostics, revealing emission components from the mass donors and sharp images of the accretion discs. Furthermore, we use Monte-Carlo methods to estimate the uncertainties from ensembles of Doppler maps. We compare our new methods against traditional radial velocity methods and show that they offer a valid route towards system parameter determination. Our analysis of CC Scl suggests a low mass ratio of $q=0.08\\pm0.03$ with a primary velocity of $K_1=37\\pm14$ km/s. This mass ratio is in between the pre- and post-period minimum status, however our $K_1$ solution favours a post-period minimum system. Our derived parameters for V2051 Oph ($q= 0.16\\pm 0.03$, $K_1=97\\pm10$ km/s) are in agreement with the eclipse solution ($q=0.19\\pm0.03...

  5. Variable Stars in Leo A RR Lyraes, Short-period Cepheids, and Implications on Stellar Content

    CERN Document Server

    Dolphin, A E; Claver, J; Skillman, E D; Cole, A A; Gallagher, J S; Tolstoy, E; Dohm-Palmer, R C; Mateo, M

    2002-01-01

    We present the results of a search for short-period variable stars in Leo A. We have found 92 candidate variables, including eight candidate RR Lyrae stars. From the RR Lyraes, we measure a distance modulus of (m-M)_0 = 24.51 +/- 0.12, or 0.80 +/- 0.04 Mpc. This discovery of RR Lyraes confirms, for the first time, the presence of an ancient (> ~11 Gyr) population in Leo A accounting for at least 0.1% of the galaxy's V luminosity. We have also discovered a halo of old (> ~2 Gyr) stars surrounding Leo A, with a scale length roughly 50% larger than that of the dominant young population. We also report the discovery of a large population of Cepheids in Leo A. The median absolute magnitude of our Cepheid sample is M_V = -1.1, fainter than 96% of SMC and 99% of LMC Cepheids. Their periods are also unusual, with three Cepheids that are deduced to be pulsating in the fundamental mode having periods of under 1 day. Upon examination, these characteristics of the Leo A Cepheid population appear to be a natural extension...

  6. Illustration of the Impedance Behaviour of Extremely Low-Profile Coupled Shorted-Patches Antennas for UHF RFID of People

    Directory of Open Access Journals (Sweden)

    Milan Svanda

    2014-01-01

    Full Text Available The recently introduced coupled shorted-patches technique for the design of extremely low-profile UHF RFID tag antennas is used to illustrate the flexibility of selected feeding methods for tuning the antenna input impedance for the complex values required for matching with typical RFID chips. We present parametric studies of the impedance behaviour of dipole-excited and directly excited antennas designed for radiofrequency identification of people in the European UHF frequency band. Our study can significantly facilitate the design of this class of on-body tag antennas.

  7. Improving attosecond pulse reflection by large angle incidence for a periodic multilayer mirror in the extreme ultraviolet region

    Institute of Scientific and Technical Information of China (English)

    Lin Cheng-You; Chen Shu-Jing; Liu Da-He

    2013-01-01

    The improvement of attosecond pulse reflection by large angle incidence for a periodic multilayer mirror in the extreme ultraviolet region has been discussed.Numerical simulations of both spectral and temporal reflection characteristics of periodic multilayer mirrors under various incident angles have been analyzed and compared.It was found that the periodic multilayer mirror under a larger incidence angle can provide not only higher integrated reflectivity but also a broader reflection band with negligible dispersion,making it possible to obtain better a reflected pulse that has a higher pulse reflection efficiency and shorter pulse duration for attosecond pulse reflection.In addition,by increasing the incident angle,the promotion of attosecond pulse reflection capability has been proven for periodic multilayer mirrors with arbitrary layers.

  8. Recent changes in daily precipitation and surface air temperature extremes in mainland Portugal, in the period 1941-2007

    Science.gov (United States)

    de Lima, M. Isabel P.; Santo, Fátima Espírito; Ramos, Alexandre M.; de Lima, João L. M. P.

    2013-06-01

    Changes in the climatology of precipitation and surface air temperature are being investigated worldwide, searching for changes in variability, the mean and extreme events (maximum and minimum). By exploring recent adjustments in the climate of mainland Portugal, particularly in the intensity, frequency and duration of extreme events, this study investigates trends in selected specific indices that are calculated from daily precipitation data from 57 and surface air temperature data from 23 measuring stations scattered across the territory. Special attention is paid to regional differences and variations in seasonality. The data cover the periods 1941-2007 for precipitation, and 1941-2006 for temperature. They are explored at the annual and seasonal scales and for different sub-periods. Results show that trends in annual precipitation indices are generally weak and, overall, not statistically significant at the 5% level. Nevertheless, a decreasing trend is revealed by regional indices of total wet-day precipitation and extreme precipitation (above the 99th percentile). Seasonal precipitation exhibits significant decreasing trends in spring precipitation, while extreme heavy precipitation events, in terms of both magnitude and frequency, have become more pronounced in autumn. Results for winter and summer suggest that the extremes have not suffered any significant aggravation. Trends for air temperature are statistically more significant and marked than for precipitation and indicate general warming across the territory. This warming trend is revealed very consistently by the time series of individual stations and regional mean temperature, and is also consistent with the findings reported in other studies for Portugal and at the European scale.

  9. Three-dimensional extremely-short optical pulses in carbon nanotube arrays in the presence of an external magnetic field

    Science.gov (United States)

    Zhukov, Alexander V.; Bouffanais, Roland; Belonenko, Mikhail B.; Galkina, Elena N.

    2016-12-01

    In this paper, we study the behavior of three-dimensional extremely-short optical pulses propagating in a system made of carbon nanotubes in the presence of an external magnetic field applied perpendicular both to the nanotube axis and to the direction of propagation of the pulse. The evolution of the electromagnetic field is classically derived on the basis of the Maxwell’s equations. The electronic system of carbon nanotubes is considered in the low-temperature approximation. Our analysis reveals the novel and unique ability of controlling the shape of propagating short optical pulses by tuning the intensity of the applied magnetic field. This effect paves the way for the possible development of innovative applications in optoelectronics.

  10. Pitch Controllability Based on Airplane Model without Short-Period Approximation—Flight Simulator Experiment—

    Science.gov (United States)

    Sato, Osamu; Kobayashi, Osamu

    Pitch controllability of an airplane is very important for longitudinal flying qualities, therefore, much research has been conducted. However, it has not been clarified why pitch handling qualities degrades in the low speed, e.g. take-off and landing flight phases. On this topic, this paper investigates the effect of several parameters of the short-period mode and phugoid mode using a flight simulator. The results show the following conclusions: The difference between the initial phase angles in two modal components in the pitch attitude response to elevator step input plays the most important role in the pitch handling qualities among modal parameters; and the difference of the two modal natural frequencies has small effect on the pitch controllability even when flight speed decreases.

  11. Optical studies on a series of AlAs/GaAs short period superlattices

    CERN Document Server

    Oh, M S; Kim, Y D; Woo, D H; Koh, E H; Kim, S H; Kang, K N; Rhee, S J; Woo, J C

    1999-01-01

    We present optical studies of a series of GaAs/AlAs short period superlattices (SLs) grown by Molecular Beam Epitaxy (MBE). The structural properties were examined by X-ray diffraction measurements. Quantum confinement of the electronic states was observed in the low temperature photoluminescence (PL). Spectroscopic ellipsometric (SE) measurements were also performed to determine energies of the interband transitions at room temperature. As n increase, we found that the lower transition energies (below 4.0 eV) decrease. The results are compared with low temperature photoluminescence measurements. We found a new structure at the lower E sub 2 peak, which demonstrates the best resolution of the E sub 2 structure in these SLs so far obtained by SE.

  12. First limits on the occurrence rate of short-period planets orbiting brown dwarfs

    CERN Document Server

    He, Matthias Y; Gillon, Michaël

    2016-01-01

    Planet formation theories predict a large but still undetected population of short-period terrestrial planets orbiting brown dwarfs. Should specimens of this population be discovered transiting relatively bright and nearby brown dwarfs, the Jupiter-size and the low luminosity of their hosts would make them exquisite targets for detailed atmospheric characterisation with JWST and future ground-based facilities. The eventual discovery and detailed study of a significant sample of transiting terrestrial planets orbiting nearby brown dwarfs could prove to be useful not only for comparative exoplanetology but also for astrobiology, by bringing us key information on the physical requirements and timescale for the emergence of life. In this context, we present a search for transit-signals in archival time-series photometry acquired by the Spitzer Space Telescope for a sample of 44 nearby brown dwarfs. While these 44 targets were not particularly selected for their brightness, the high precision of their Spitzer ligh...

  13. Short period variable stars recognition by using MVA methods in Pi of the Sky experiment

    Science.gov (United States)

    Obara, L.

    2016-12-01

    Pi of the Sky is a system of wide field-of-view robotic telescopes to search for short timescale astrophysical phenomena, especially for prompt optical GRB emission. The system was designed for autonomous operation, monitoring a large fraction of the sky with limit magnitude in the range 12m-13m and time resolution on the order of 1-100 seconds. LUIZA is a dedicated framework developed for efficient off-line processing of the Pi of the Sky data, implemented in C++. The photometric algorithm based on the All Sky Automated Survey (ASAS) photometry was implemented in LUIZA and compared with the algorithm based on the pixel cluster reconstruction and simple aperture photometry algorithm. Optimized photometry algorithms were then applied to the sample of test images, which were modified to include different patterns of variability of the stars in training sample. Different statistical estimators were considered for developing the general variable star identification algorithm. The algorithm will be used to search for short-period variable stars in real data.

  14. Searching the short-period variable stars with the photometric algorithm implemented in LUIZA framework

    Science.gov (United States)

    Obara, Lukasz; Żarnecki, Aleksander Filip

    2015-09-01

    Pi of the Sky is a system of wide field-of-view robotic telescopes, which search for short timescale astrophysical phenomena, especially for prompt optical GRB emission. The system was designed for autonomous operation, monitoring a large fraction of the sky with 12m-13m range and time resolution of the order of 1 - 100 seconds. LUIZA is a dedicated framework developed for efficient off-line processing of the Pi of the Sky data, implemented in C++. The photometric algorithm based on ASAS photometry was implemented in LUIZA and compared with the algorithm based on the pixel cluster reconstruction and simple aperture photometry algorithm. Optimized photometry algorithms were then applied to the sample of test images, which were modified to include different patterns of variability of the stars (training sample). Different statistical estimators are considered for developing the general variable star identification algorithm. The algorithm will then be used to search for short-period variable stars in the real data.

  15. Phase and period responses of the jerboa Jaculus orientalis to short light pulses.

    Science.gov (United States)

    El Moussaouiti, Rachid; Bouhaddou, Nezha; Sabbar, Mariam; Cooper, Howard M; Lakhdar-Ghazal, Nouria

    2010-08-01

    The phase and period responses to short light pulses were studied in the jerboa, a seasonal, hibernating, nocturnal rodent from the Atlas region in Morocco. The jerboa, which is a saltatory species, showed precise activity onsets and offsets under a light-dark (LD) cycle using infrared captors to record locomotor activity. When released into constant darkness (DD), the majority of animals showed a circadian period (tau) light pulses, each separated by at least 2 wks, for up to 160 days in DD. During this span, most individuals maintained robust circadian rhythmicity, with clearly defined activity onsets and offsets, similar levels of total activity, duration of alpha, and percent activity occurring during the subjective night. The phase response curve (PRC) is typical of other nocturnal rodents, with light eliciting delays during late subjective day and early subjective night (CT8-CT19) and advances during late subjective night to early subjective day (CT19-CT2). A dead zone, when light had no effect on phase, is observed during mid-subjective day (CT3-CT8). A few individuals showed large (> 9 h) Type 0 phase resetting near the singularity region (CT19) that resulted in a complete phase reversal, but otherwise displayed normal phase-shifting responses at other CT times. The tau response curve showed a decrease in period from early to late subjective night with increases at other times, but these changes were small (maximum light pulses and, inversely, for animals with long tau to conserve a long tau. This suggests possible constraints on the plasticity of variation of tau in relation to the endogenous period of the animal.

  16. THE VERY SHORT PERIOD M DWARF BINARY SDSS J001641-000925

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, James R. A.; Becker, Andrew C.; Hawley, Suzanne L.; Gunning, Heather C.; Munshi, Ferah A.; Albright, Meagan [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); West, Andrew A. [Astronomy Department, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Bochanski, John J. [Astronomy and Astrophysics Department, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Holtzman, Jon [Department of Astronomy, New Mexico State University, Box 30001, Las Cruces, NM 88003 (United States); Hilton, Eric J., E-mail: jrad@astro.washington.edu [Department of Geology and Geophysics and Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2013-02-10

    We present follow-up observations and analysis of the recently discovered short period low-mass eclipsing binary, SDSS J001641-000925. With an orbital period of 0.19856 days, this system has one of the shortest known periods for an M dwarf binary system. Medium-resolution spectroscopy and multi-band photometry for the system are presented. Markov Chain Monte Carlo modeling of the light curves and radial velocities yields estimated masses for the stars of M {sub 1} = 0.54 {+-} 0.07 M {sub Sun} and M {sub 2} = 0.34 {+-} 0.04 M {sub Sun }, and radii of R {sub 1} = 0.68 {+-} 0.03 R {sub Sun} and R {sub 2} = 0.58 {+-} 0.03 R {sub Sun }, respectively. This solution places both components above the critical Roche overfill limit, providing strong evidence that SDSS J001641-000925 is the first verified M-dwarf contact binary system. Within the follow-up spectroscopy we find signatures of non-solid body rotation velocities, which we interpret as evidence for mass transfer or loss within the system. In addition, our photometry samples the system over nine years, and we find strong evidence for period decay at the rate of P-dot {approx} 8 s yr{sup -1}. Both of these signatures raise the intriguing possibility that the system is in over-contact, and actively losing angular momentum, likely through mass loss. This places SDSS J001641-000925 as not just the first M-dwarf over-contact binary, but one of the few systems of any spectral type known to be actively undergoing coalescence. Further study of SDSS J001641-000925 is ongoing to verify the nature of the system, which may prove to be a unique astrophysical laboratory.

  17. Stress reaction in freshwater ifsh in response to extreme impacts and during the reproduction period

    Institute of Scientific and Technical Information of China (English)

    Vladimir Ivamovich; Martemyanov

    2015-01-01

    The original and published data on the physiological and biochemical reactions in fish in response to stress impact and during the reproduction period are presented. It is shown that at the initial period of stress and before spawning the protective functions in fish are enhanced which relates to the adaptation syndrome. However, during the initial period of stress the damaging effects prevail over the adaptive processes resulting in the decrease in the level of resistance (“alarm reaction” according to Selye). In contrary, during pre-spawning period protective systems dominate along with enhancement of general adaptation syndromes. This facilitates the increase in the level of resistance in the parental fish (“resistance stage”according to Selye). Before the spawning the alarm stage is not manifested. The state comparable to strong stress occurs in the parental fish only during the spawning. This state is accompanied by decrease in the resistance of organism in spawner evidencing exhaustion of protective functions (“exhaustion stage” according to Selye). With time, both at stress and after spawning, within two to three weeks period, the physiological-biochemical parameters recover and stabilize with the normal limits.

  18. Inheritance of a long juvenile period under short-day conditions in soybean

    Directory of Open Access Journals (Sweden)

    Valéria Carpentieri-Pípolo

    2002-01-01

    Full Text Available The long juvenile period (LJP characteristic of soybean (Glycine max L. Merrill cultivars delays flowering under short-day conditions. This trait may be important in increasing the adaptation range of soybean to low latitudes and provides greater flexibility for sowing times within the same latitude. The inheritance of the long juvenile period was studied in the MG/BR22 (Garimpo soybean cultivar to provide knowledge to support the development of cultivars adapted to short day conditions. Four cultivars (‘Paraná’, ‘Bossier’, ‘Bragg’, and ‘Davis’ were crossed among each other and with MG/BR 22 (‘Garimpo’. The study was conducted under short-day conditions (early sowing in a greenhouse and in the field, in Londrina, Paraná, (23°22’ south latitude. The parents and the F1, F2, and F3 populations were assessed daily for flowering. The genotype ratios of 15:1 (p > 0.95, chi² test and 8:7:1 (p = 0.193 for the F2 and F3 generations, respectively, obtained for the Paraná x Bossier cross indicated a case of digenic interaction with a duplicate recessive epistatic effect for the LJP character. Segregation of the F2 population from the MG/BR 22 (Garimpo x Paraná cross resulted in the expected ratio of 3:1 (p = 0.166, indicating that the MG/BR 22 (Garimpo and Paraná cultivars differed at a single locus. Similarly, in the MG/BR 22 (Garimpo x Bossier cross, a 3:1 (p = 0.065 segregation indicated that these two cultivars differed at a single locus for number of days to flowering. The Davis cultivar had the same gene for LJP as the Paraná cultivar (aa. The F2 segregation of the classic flowering Bragg with MG/BR 22 (Garimpo cross resulted in a 15:1 (p = 0.138 ratio, indicating that these two cultivars differed at two loci for flowering. The genotypes assigned to the cultivars were aaBB for Paraná, AAbb for Bossier and aabb for MG/BR 22 (Garimpo. A single locus in recessive homozygosis does not produce LJP.

  19. The OmegaWhite Survey for Short-Period Variable Stars I: Overview and First Results

    CERN Document Server

    Macfarlane, S A; Ramsay, G; Groot, P J; Woudt, P A; Drew, J E; Barentsen, G; Eisloffel, J

    2015-01-01

    We present the goals, strategy and first results of the OmegaWhite survey: a wide-field high-cadence $g$-band synoptic survey which aims to unveil the Galactic population of short-period variable stars (with periods $<$ 80 min), including ultracompact binary star systems and stellar pulsators. The ultimate goal of OmegaWhite is to cover 400 square degrees along the Galactic Plane reaching a depth of $g = $ 21.5 mag (10$\\sigma$), using OmegaCam on the VLT Survey Telescope (VST). The fields are selected to overlap with surveys such as the Galactic Bulge Survey (GBS) and the VST Photometric H$\\alpha$ Survey of the Southern Galactic Plane (VPHAS+) for multi-band colour information. Each field is observed using 38 exposures of 39 s each, with a median cadence of $\\sim$2.7 min for a total duration of two hours. Within an initial 26 square degrees, we have extracted the light curves of 1.6 million stars, and have identified 613 variable candidates which satisfy our selection criteria. Furthermore, we present the ...

  20. Photometric Study of the near-contact short period Algol system, AK Canis Minoris

    Science.gov (United States)

    Samec, Ronald G.; McDermith, Richard J.; Gray, Jamison D.; Carrigan, Brian

    1995-05-01

    As a part of our departments new undergraduate research program, we are surveying the eccentric eclipsing binary (EEB) candidates of Hegedus (1988). AK CMi is listed as a system with a displaced secondary. The observations were taken 10 to 15 February 1994, inclusive, at Lowell Obsevatory, Flagstaff, Arizona. A thermoelectrically cooled EMI 6256S ( S-13 cathode) PMT was used in conjunction with the 0.78 m National Undergraduate Research Observatory reflector. Two precision epochs of minimicrons light were determined from the observations made during primary and secondary eclipses. They are: Min I = 2449396.7032(5) and Min II = 2449395.8546(3). Targeting the last twenty-three years of data, we calculated improved linear and quadratic ephemerides. The quadratic term, -1.0(2)E-10, suggests that AK CMi is undergoing a continuous period decrease. This may be due to magnetic braking arising from the fast rotating solar-type secondary component. There is little evidence from the present light curves that AK CMi has a eccentric orbit. Assymetries near secondary minima possibly induced by an intermittent gas stream may be responsible for the classification of AK CMi as an EEB. The light curve solution reveals that AK CMi is a short period Algol with an A spectral-type primary component and an early K-type secondary. We calculated mass ratio of 0.5 and a secondary component fillout of 90% showing that AK CMi is a near contact binary.

  1. The Hypervelocity Star SDSS J090745.0+024507 is a Short-Period Variable

    CERN Document Server

    Fuentes, C I; Gaudi, B S; McLeod, B A; Bogdanov, S B; Hartman, J D; Hickox, R C; Holman, M J; Fuentes, Cesar I.; Leod, Brian A. Mc; Bogdanov, Slavko B.; Hartman, Joel D.; Hickox, Ryan C.; Holman, Matthew J.

    2005-01-01

    We present high-precision photometry of the hypervelocity star SDSS J090745.0+024507 (HVS), which has a Galactic rest-frame radial velocity of v=709 km/s, and so has likely been ejected from the supermassive black hole in the Galactic center. Our data were obtained on two nights using the MMT 6.5m telescope, and is supplemented by lower precision photometry obtained on four nights using the FLWO 1.2m telescope. The high-precision photometry indicates that the HVS is a short-period, low-amplitude variable, with period P=0.2-2 days and amplitude A = 2-10%. Together with the known effective temperature of T_eff ~ 10,500 K (spectral type B9), this variability implies that the HVS is a member of the class of slowly pulsating B-type main sequence stars, thus resolving the previously-reported two-fold degeneracy in the luminosity and distance of the star. The HVS has a heliocentric distance of 71 kpc, and an age of ~0.35 Gyr. The time of ejection from the center of the Galaxy is < 100 Myr, and thus the existence ...

  2. First spectral measurements of a cryogenic high-field short-period undulator

    Directory of Open Access Journals (Sweden)

    F. Holy

    2014-05-01

    Full Text Available Further development of synchrotron light sources and new concepts for free electron lasers require undulators with short periods and high magnetic fields. A promising approach is the cryogenic permanent magnet undulator concept based on an advanced magnet material. This new rare earth alloy (Pr,Nd_{2}Fe_{14}B, shows an increasing remanent field of up to 1.7 T without the limits of spin reorientation transition. This work presents first spectral measurements of a prototype cryogenic permanent magnet undulator, consisting of 20 periods of 9 mm in length, cooled by a closed cycle cryo-cooler to temperatures below 30 K. The K parameter of 0.837 at RT is increased by more than 15% to 0.966, and an increase of the third harmonics photon flux of up to 66% was achieved. A possible degradation of the on-axis field quality due to thermally induced magnetic field errors, deduced from the measured bandwidth of the spectrum, is below the limits of the detector resolution of 2%.

  3. Site response zones and short-period earthquake ground motion projections for the Las Vegas Basin

    Indian Academy of Sciences (India)

    Barbara Luke; Ying Liu

    2008-11-01

    A deterministic seismic hazard analysis was conducted to address the effect of local soil conditions on earthquake-induced strong ground motion in the Las Vegas Basin, Nevada (US). Using a large geological and geotechnical database, two response units were defined: a fine-grained unit, predominantly clay; and a coarse-grained unit, predominantly gravel. A moderate number of high-quality shallow shear wave velocity measurements were collected from which characteristic shear wave velocity profiles were developed for each response unit. An equivalent-linear one-dimensional site response model was used. The model was calibrated using a basin-wide, small-strain ground motion database. Calibration tests showed that ground motion projections become increasingly conservative with increasing ground-motion amplitude. Projections were overconservative for the coarsegrained response unit, likely due to the sparseness of the velocity database. For the earthquake response analyses, historical ground motions were used to model characteristic ‘bedrock’ motion for earthquakes on 10 faults judged to be critical. Response spectral envelopes were generated for each unit through Monte-Carlo simulations. For the fine-grained response unit, 95th percentile peak ground acceleration, peak spectral acceleration and predominant period were 310 cm/s2, 1100cm/s2, and 0.29 s, respectively. With respect to codified design spectra, projections are lower at short periods and higher at long periods. Projections of peak spectral accelerations for the coarsegrained response unit, were more than double that of codified spectra; however, they are believed to be overconservative. Near-fault effects and basin-edge effects, though potentially important, were not considered in these analyses.

  4. The K2-ESPRINT Project V: A Short-period Giant Planet Orbiting a Subgiant Star*

    Science.gov (United States)

    Van Eylen, Vincent; Albrecht, Simon; Gandolfi, Davide; Dai, Fei; Winn, Joshua N.; Hirano, Teriyuki; Narita, Norio; Bruntt, Hans; Prieto-Arranz, Jorge; Béjar, Víctor J. S.; Nowak, Grzegorz; Lund, Mikkel N.; Palle, Enric; Ribas, Ignasi; Sanchis-Ojeda, Roberto; Yu, Liang; Arriagada, Pamela; Butler, R. Paul; Crane, Jeffrey D.; Handberg, Rasmus; Deeg, Hans; Jessen-Hansen, Jens; Johnson, John A.; Nespral, David; Rogers, Leslie; Ryu, Tsuguru; Shectman, Stephen; Shrotriya, Tushar; Slumstrup, Ditte; Takeda, Yoichi; Teske, Johanna; Thompson, Ian; Vanderburg, Andrew; Wittenmyer, Robert

    2016-11-01

    We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 (EPIC 206247743) is an evolved star with a spectroscopically derived stellar radius and mass of {3.88}-0.42+0.48 {R}ȯ and {1.53}-0.12+0.13 {M}ȯ , respectively, and a very close-in transiting planet, with a/{R}\\star =3.4. Radial velocity (RV) follow-up using the HARPS, FIES, and PFS instruments leads to a planetary mass of {50.3}-9.4+9.7 {M}\\oplus . In combination with a radius measurement of 8.3+/- 1.1 {R}\\oplus , this results in a mean planetary density of {0.50}-0.17+0.29 g cm‑3. We furthermore discover a long-term RV trend, which may be caused by a long-period planet or stellar companion. Because K2-39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and main-sequence stars. Future monitoring of the transits of this system may enable the detection of period decay and constrain the tidal dissipation rates of subgiant stars. Based on observations made with the NOT telescope under program ID. 50-022/51-503, 50-213(CAT), 52-201 (CAT), 52-108 (OPTICON), 51-211 (CAT), and ESOs 3.6 m telescope at the La Silla Paranal Observatory under program ID 095.C-0718(A).

  5. Phase and period responses to short light pulses in a wild diurnal rodent, Funambulus pennanti.

    Science.gov (United States)

    Kumar, Dhanananajay; Singaravel, Muniyandi

    2014-04-01

    Photic phase response curves (PRCs) have been extensively studied in many laboratory-bred diurnal and nocturnal rodents. However, comparatively fewer studies have addressed the effects of photic cues on wild diurnal mammals. Hence, we studied the effects of short durations of light pulses on the circadian systems of the diurnal Indian Palm squirrel, Funambulus pennanti. Adult males entrained to a light-dark cycle (12 h-12 h) were transferred to constant darkness (DD). Free-running animals were exposed to brief light pulses (250 lux) of 15 min, 3 circadian hours (CT) apart (CT 0, 3, 6, 9, 12, 15, 18 and 21). Phase shifts evoked at different phases were plotted against CT and a PRC was constructed. F. pennanti exhibited phase-dependent phase shifts at all the CTs studied, and the PRC obtained was of type 1 at the intensity of light used. Phase advances were evoked during the early subjective day and late subjective night, while phase delays occurred during the late subjective day and early subjective night, with maximum phase delay at CT 15 (-2.04 ± 0.23 h), and maximum phase advance at CT 21 (1.88 ± 0.31 h). No dead zone was seen at this resolution. The free-running period of the rhythm was concurrently lengthened (deceleration) during the late subjective day and early subjective night, while period shortening (acceleration) occurred during the late subjective night. The maximum deceleration was noticed at CT 15 (-0.40 ± 0.09 h) and the maximum acceleration at CT 21 (0.39 ± 0.07 h). A significant positive correlation exists between the phase shifts and the period changes (r = 0.684, p = 0.001). The shapes of both the PRC and period response curve (τRC) qualitatively resemble each other. This suggests that the palm squirrel's circadian system is entrained both by phase and period responses to light. Thus, F. pennanti exhibits robust clock-resetting in response to light pulses.

  6. A lack of short-period multiplanet systems with close-proximity pairs and the curious case of Kepler 42

    CERN Document Server

    Steffen, Jason H

    2013-01-01

    Many Kepler multiplanet systems have planet pairs near low-order, mean-motion resonances. In addition, many Kepler multiplanet systems have planets with orbital periods less than a few days. With the exception of Kepler-42, however, there are no examples of systems with both short orbital periods and nearby companion planets while our modeling predicts ~17 such pairs. For orbital periods of the inner planet that are less than three days, the minimum period ratio of adjacent planet pairs follows the rough constraint P_2/P_1 >~ 2.3 (P_1/day)^(-2/3). This excess is not due to a lack of planets with short orbital periods. We also show a statistically significant excess of small, single candidate systems with orbital periods below 3 days over the number of multiple candidate systems with similar periods---perhaps a small-planet counterpart to the hot Jupiters.

  7. Type III events, flares and CMEs, in the extremely active period October-November 2003

    CERN Document Server

    Mitsakou, E; Preka-Papadema, P; Moussas, X; Hillaris, A; Caroubalos, C; Alissandrakis, C E; Tsitsipis, P; Kontogeorgos, A; Bougeret, J -L; Dumas, G; 10.1063/1.2347984

    2010-01-01

    The type III observations trace the propagation of energetic electron populations through the Solar Corona which, more often than not, precede or are associated with energy release on the Sun. A sample of Type III bursts in the range 20-650 MHz during the period of extraordinary solar activity (20 October to 4 November 2003) recorded by the ARTEMIS-IV1 radio spectrograph is analysed; its parameters are compared with characteristics of associated flares (Ha and GOES SXR) and CMEs, observed in the same period and reported in the SGR and the LASCO archives respectively. In this report we attempt to establish a correlation between energetic particles and major manifestations of solar activity such as flares and CMEs.

  8. Effects of Short-Term Free-Weight and Semiblock Periodization Resistance Training on Metabolic Syndrome.

    Science.gov (United States)

    South, Mark A; Layne, Andrew S; Stuart, Charles A; Triplett, N Travis; Ramsey, Michael; Howell, Mary E; Sands, William A; Mizuguchi, Satoshi; Hornsby, W Guy; Kavanaugh, Ashley A; Stone, Michael H

    2016-10-01

    South, MA, Layne, AS, Stuart, CA, Triplett, NT, Ramsey, MW, Howell, ME, Sands, WA, Mizuguchi, S, Hornsby, WG, Kavanaugh, AA, and Stone, MH. Effects of short-term free-weight and semiblock periodization resistance training on metabolic syndrome. J Strength Cond Res 30(10): 2682-2696, 2016-The effects of short-term resistance training on performance and health variables associated with prolonged sedentary lifestyle and metabolic syndrome (MS) were investigated. Resistance training may alter a number of health-related, physiological, and performance variables. As a result, resistance training can be used as a valuable tool in ameliorating the effects of a sedentary lifestyle including those associated with MS. Nineteen previously sedentary subjects (10 with MS and 9 with nonmetabolic syndrome [NMS]) underwent 8 weeks of supervised resistance training. Maximum strength was measured using an isometric midthigh pull and resulting force-time curve. Vertical jump height (JH) and power were measured using a force plate. The muscle cross-sectional area (CSA) and type were examined using muscle biopsy and standard analysis techniques. Aerobic power was measured on a cycle ergometer using a ParvoMedics 2400 Metabolic system. Endurance was measured as time to exhaustion on a cycle ergometer. After training, maximum isometric strength, JH, jump power, and V[Combining Dot Above]O2peak increased by approximately 10% (or more) in both the metabolic and NMS groups (both male and female subjects). Over 8 weeks of training, body mass did not change statistically, but percent body fat decreased in subjects with the MS and in women, and lean body mass increased in all groups (p ≤ 0.05). Few alterations were noted in the fiber type. Men had larger CSAs compared those of with women, and there was a fiber-specific trend toward hypertrophy over time. In summary, 8 weeks of semiblock free-weight resistance training improved several performance variables and some cardiovascular factors

  9. Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data

    Science.gov (United States)

    Prsa, Andrej

    Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. Eclipsing binary stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached binaries host low-mass (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary

  10. Effects of Short Term Camp Periods on Aerobic and Anaerobic Performance Parameters in Ice Hockey National Team Athletes

    Science.gov (United States)

    Eler, Serdar

    2016-01-01

    This study was conducted for determining the effects of trainings, applied to athletes during short term camp period, on their aerobic and anaerobic performance. Measurements were made by the participation of 28 volunteer male ice hockey national team players. During the 15-day camp period, 10-minute running and stretching for warming and then…

  11. Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

    Directory of Open Access Journals (Sweden)

    Cottrell Greg

    2009-01-01

    Full Text Available Abstract Background Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT has recently been demonstrated to produce improvements to aerobic function, but it is unknown whether HIT has the capacity to improve insulin action and hence glycemic control. Methods Sixteen young men (age: 21 ± 2 y; BMI: 23.7 ± 3.1 kg·m-2; VO2peak: 48 ± 9 ml·kg-1·min-1 performed 2 weeks of supervised HIT comprising of a total of 15 min of exercise (6 sessions; 4–6 × 30-s cycle sprints per session. Aerobic performance (250-kJ self-paced cycling time trial, and glucose, insulin and NEFA responses to a 75-g oral glucose load (oral glucose tolerance test; OGTT were determined before and after training. Results Following 2 weeks of HIT, the area under the plasma glucose, insulin and NEFA concentration-time curves were all reduced (12%, 37%, 26% respectively, all P -1, P = 0.058. Insulin sensitivity, as measured by the Cederholm index, was improved by 23% (P Conclusion The efficacy of a high intensity exercise protocol, involving only ~250 kcal of work each week, to substantially improve insulin action in young sedentary subjects is remarkable. This novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle aged sedentary populations who otherwise would not adhere to time consuming traditional aerobic exercise regimes.

  12. Discovery of a short-necked sauropod dinosaur from the Late Jurassic period of Patagonia.

    Science.gov (United States)

    Rauhut, Oliver W M; Remes, Kristian; Fechner, Regina; Cladera, Gerardo; Puerta, Pablo

    2005-06-01

    Sauropod dinosaurs are one of the most conspicuous groups of Mesozoic terrestrial vertebrates. They show general trends towards an overall increase in size and elongation of the neck, by means of considerable elongation of the length of individual vertebrae and a cervical vertebra count that, in some cases, increases to 19 (ref. 1). The long neck is a particular hallmark of sauropod dinosaurs and is usually regarded as a key feeding adaptation. Here we describe a new dicraeosaurid sauropod, from the latest Jurassic period of Patagonia, that has a particularly short neck. With a neck that is about 40% shorter than in other known dicraeosaurs, this taxon demonstrates a trend opposite to that seen in most sauropods and indicates that the ecology of dicraeosaurids might have differed considerably from that of other sauropods. The new taxon indicates that there was a rapid radiation and dispersal of dicraeosaurids in the Late Jurassic of the Southern Hemisphere, after the separation of Gondwana from the northern continents by the late Middle Jurassic.

  13. Ontogeny of sensorimotor gating and short-term memory processing throughout the adolescent period in rats

    Directory of Open Access Journals (Sweden)

    Anja A. Goepfrich

    2017-06-01

    Full Text Available Adolescence and puberty are highly susceptible developmental periods during which the neuronal organization and maturation of the brain is completed. The endocannabinoid (eCB system, which is well known to modulate cognitive processing, undergoes profound and transient developmental changes during adolescence. With the present study we were aiming to examine the ontogeny of cognitive skills throughout adolescence in male rats and clarify the potential modulatory role of CB1 receptor signalling. Cognitive skills were assessed repeatedly every 10th day in rats throughout adolescence. All animals were tested for object recognition memory and prepulse inhibition of the acoustic startle reflex. Although cognitive performance in short-term memory as well as sensorimotor gating abilities were decreased during puberty compared to adulthood, both tasks were found to show different developmental trajectories throughout adolescence. A low dose of the CB1 receptor antagonist/inverse agonist SR141716 was found to improve recognition memory specifically in pubertal animals while not affecting behavioral performance at other ages tested. The present findings demonstrate that the developmental trajectory of cognitive abilities does not occur linearly for all cognitive processes and is strongly influenced by pubertal maturation. Developmental alterations within the eCB system at puberty onset may be involved in these changes in cognitive processing.

  14. High-precision photometry by telescope defocussing. VII. The ultra-short period planet WASP-103

    CERN Document Server

    Southworth, John; Ciceri, S; Budaj, J; Dominik, M; Jaimes, R Figuera; Haugbolle, T; Jorgensen, U G; Popovas, A; Rabus, M; Rahvar, S; von Essen, C; Schmidt, R W; Wertz, O; Alsubai, K A; Bozza, V; Bramich, D M; Novati, S Calchi; D'Ago, G; Hinse, T C; Henning, Th; Hundertmark, M; Juncher, D; Korhonen, H; Skottfelt, J; Snodgrass, C; Starkey, D; Surdej, J

    2014-01-01

    We present 17 transit light curves of the ultra-short period planetary system WASP-103, a strong candidate for the detection of tidally-induced orbital decay. We use these to establish a high-precision reference epoch for transit timing studies. The time of the reference transit midpoint is now measured to an accuracy of 4.8s, versus 67.4s in the discovery paper, aiding future searches for orbital decay. With the help of published spectroscopic measurements and theoretical stellar models, we determine the physical properties of the system to high precision and present a detailed error budget for these calculations. The planet has a Roche lobe filling factor of 0.58, leading to a significant asphericity; we correct its measured mass and mean density for this phenomenon. A high-resolution Lucky Imaging observation shows no evidence for faint stars close enough to contaminate the point spread function of WASP-103. Our data were obtained in the Bessell $RI$ and the SDSS $griz$ passbands and yield a larger planet ...

  15. Dust environment and dynamical history of a sample of short period comets

    CERN Document Server

    Pozuelos, F J; Aceituno, F; Casanova, V; Sota, A; López-Moreno, J J; Castellano, J; Reina, E; Diepvens, A; Betoret, A; Häusler, B; González, C; Rodríguez, D; Bryssinck, E; Cortés, E; García, F; García, F; Limón, F; Grau, F; Fratev, F; Baldrís, F; Rodriguez, F A; Montalbán, F; Soldán, F; Muler, G; Almendros, I; Temprano, J; Bel, J; Sánchez, J; Lopesino, J; Báez, J; Hernández, J F; Martín, J L; Ruiz, J M; Vidal, J R; Gaitán, J; Salto, J L; Aymamí, J M; Bosch, J M; Henríquez, J A; Martín, J J; Lacruz, J; Tremosa, L; Lahuerta, L; Reszelsky, M; Rodríguez, M; Camarasa, M; Campas, M; Canales, O; Dekelver, P J; Moreno, Q; Benavides, R; Naves, R; Dymoc, R; García, R; Lahuerta, S; Climent, T

    2014-01-01

    Aims. In this work, we present an extended study of the dust environment of a sample of short period comets and their dynamical history. With this aim, we characterized the dust tails when the comets are active, and we made a statistical study to determine their dynamical evolution. The targets selected were 22P/Kopff, 30P/Reinmuth 1, 78P/Gehrels 2, 115P/Maury, 118P/Shoemaker-Levy 4, 123P/West-Hartley, 157P/Tritton, 185/Petriew, and P/2011 W2 (Rinner). Methods. We use two different observational data: a set of images taken at the Observatorio de Sierra Nevada and the Afrho curves provided by the amateur astronomical association Cometas-Obs. To model these observations, we use our Monte Carlo dust tail code. From this analysis, we derive the dust parameters, which best describe the dust environment: dust loss rates, ejection velocities, and size distribution of particles. On the other hand, we use a numerical integrator to study the dynamical history of the comets, which allows us to determine with a 90% of co...

  16. Fabrication and characterization of short-period double-layer cross-grating with holographic lithography

    Science.gov (United States)

    Lin, Cunbao; Yan, Shuhua; You, Fusheng

    2017-01-01

    A cross-grating with short period and double layer is designed, and a method combining holographic lithography and lithography-etch-lithography-etch is proposed to manufacture it. The scalar diffraction theory and the rigorous coupled wave analysis are employed to analyze the diffraction characteristics of the double-layer cross-grating (DLCG). It reveals that the efficiencies of the (±1,±1) orders possess perfect complementarity under normal incidence. The equivalent high efficiency for TE and TM polarization can be realized which means the high signal-to-noise ratio and fringe contrast can be simultaneously achieved for heterodyne grating interferometers (HGIs). Furthermore, a gold-coated DLCG with grating pitch of 2 μm and pattern area of 60 mm×60 mm etched on the quartz substrate is fabricated with the proposed method. The displacement resolution, measurement range and long-term stability can be reliably guaranteed for HGIs with this grating. The characteristics of the DLCG are also experimentally tested and compared with the theoretical analysis. Reasonable consistency is obtained and the capabilities of both the DLCG and the fabrication method are verified.

  17. A neutral network based technique for short-term forecasting of anomalous load periods

    Energy Technology Data Exchange (ETDEWEB)

    Sforna, M. [ENEL, s.p.a, Italian Power Company (Italy); Lamedica, R.; Prudenzi, A. [Rome Univ. `La Sapienza`, Rome (Italy); Caciotta, M.; Orsolini Cencelli, V. [Rome Univ. III, Rome (Italy)

    1995-01-01

    The paper illustrates a part of the research activity conducted by authors in the field of electric Short Term Load Forecasting (STLF) based on Artificial Neural Network (ANN) architectures. Previous experiences with basic ANN architectures have shown that, even though these architecture provide results comparable with those obtained by human operators for most normal days, they evidence some accuracy deficiencies when applied to `anomalous` load conditions occurring during holidays and long weekends. For these periods a specific procedure based upon a combined (unsupervised/supervised) approach has been proposed. The unsupervised stage provides a preventive classification of the historical load data by means of a Kohonen`s Self Organizing Map (SOM). The supervised stage, performing the proper forecasting activity, is obtained by using a multi-layer percept ron with a back propagation learning algorithm similar to the ones above mentioned. The unconventional use of information deriving from the classification stage permits the proposed procedure to obtain a relevant enhancement of the forecast accuracy for anomalous load situations.

  18. The Eccentricity Distribution of Short-Period Planet Candidates Detected by Kepler in Occultation

    CERN Document Server

    Shabram, Megan; Cisewski, Jessi; Ford, Eric B; Rogers, Leslie

    2015-01-01

    We characterize the eccentricity distribution of a sample of ~50 short-period planet candidates using transit and occultation measurements from NASA's Kepler Mission. First, we evaluate the sensitivity of our hierarchical Bayesian modeling and test its robustness to model misspecification using simulated data. When analyzing actual data assuming a Rayleigh distribution for eccentricity, we find that the posterior mode for the dispersion parameter is $\\sigma=0.081 \\pm^{0.014}_{0.003}$. We find that a two-component Gaussian mixture model for $e \\cos \\omega$ and $e \\sin \\omega$ provides a better model than either a Rayleigh or Beta distribution. Based on our favored model, we find that $\\sim90\\%$ of planet candidates in our sample come from a population with an eccentricity distribution characterized by a small dispersion ($\\sim0.01$), and $\\sim10\\%$ come from a population with a larger dispersion ($\\sim0.22$). Finally, we investigate how the eccentricity distribution correlates with selected planet and host sta...

  19. Observation of a Short Period Quasi-periodic Pulsation in Solar X-Ray, Microwave, and EUV Emissions

    Science.gov (United States)

    Kumar, Pankaj; Nakariakov, Valery M.; Cho, Kyung-Suk

    2017-02-01

    This paper presents the multiwavelength analysis of a 13 s quasi-periodic pulsation (QPP) observed in hard X-ray (12–300 keV) and microwave (4.9–34 GHz) emissions during a C-class flare that occurred on 2015 September 21. Atmospheric Image Assembly (AIA) 304 and 171 Å images show an emerging loop/flux tube (L1) moving radially outward, which interacts with the preexisting structures within the active region (AR). The QPP was observed during the expansion of and rising motion of L1. The Nobeyama Radioheliograph microwave images in 17/34 GHz channels reveal a single radio source that was co-spatial with a neighboring loop (L2). In addition, using AIA 304 Å images, we detected intensity oscillations in the legs of L2 with a period of about 26 s. A similar oscillation period was observed in the GOES soft X-ray flux derivative. This oscillation period seems to increase with time. We suggest that the observed QPP is most likely generated by the interaction between L2 and L3 observed in the AIA hot channels (131 and 94 Å). The merging speed of loops L2 and L3 was ∼35 km s‑1. L1 was destroyed possibly by its interaction with preexisting structures in the AR, and produced a cool jet with the speed of ∼106–118 km s‑1 associated with a narrow CME (∼770 km s‑1). Another mechanism of the QPP in terms of a sausage oscillation of the loop (L2) is also possible.

  20. Characterizing Composition Modulations in InAs/AIAs Short-Period Superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Ahrenkiel, S.P.; Follstaedt, D.M.; Jones, E.D.; Lee, S.R.; Mascarenhas, A.; Millunchick, J. Mirecki; Norman, A.G.; Reno, J.L.; Twesten, R.D.

    1999-04-26

    The formation of quantum wires has much interest due to their novel electronic properties which may lead to enhanced optoelectronic device performance and greater photovoltaic efficiencies. One method of forming these structures is through spontaneous lateral modulation found during the epitaxial growth of III/V alloys. In this paper, we report and summarize our investigations on the formation of lateral moduation in the MBE grown InAlAs/InP(001) system. This system was grown as a short-period superlattice where n-monolayers of InAs are deposited followed by m-Monolayers of AlAs (with n and m~2) and this sequence is repeated to grown a low strain InAlAs ternary alloy on InP(001) that exhibits lateral modulation. Films were grown under a variety of condition (growth temperature, effective alloy composition, superlattice period, and growth rate). These films have been extensively analyzed using X-ray diffraction, atomic force microscopy, and transmission electron microscopy (TEM) and microcharacterization, in addition to photon-based spectroscopes. Here we present results of several microstructural characterizations using a wide range of TEM-based techniques, and compare them to results from the other methods to obtain a unified understanding of composition modulation. Two strong points consistently emerge: 1) The lateral modulation wavelength is insensitive to growth temperature and effective alloy composition, but the strength of the lateral modulation is greatest near an effective alloy composition of In(0.46)Al(0.54)As, which corresponds to a slightly tensile global strain with respect to InP. 2) The composition variation for the strongly modulated films is as much as 0.38 InAs mole fraction. In addition, for these strongly modulated films, the modulation wave is asymmetric showing strongly peaked, narrower InAs-rich regions separated by flat AlAs-rich regions. We discuss these results and their possible implications in addition to detailing the techniques used

  1. Discrimination of teleseismic events in Central Asia with a local network of short period stations

    Directory of Open Access Journals (Sweden)

    M. Tarvainen

    1994-06-01

    Full Text Available The difficult problem of distinguishing underground nuclear explosions from earthquakes at teleseismie distances was approached using short period seismic data from 6 stations in South and Central Finland. The events were nuclear tests mostly from the Semipalatinsk and Lop Nor test sites and earthquakes from adjacent areas. The magnitude range of the events was from 4.1 to 6.6. The features of the two classes of events were examined by computing spectral ratio, third moment of frequency (TMF and complexity from P wave signals. The spectral discrimination parameters were extracted from spectra computed in 5 different ways in order to obtain all possible information even from weak events. The standard FFT spectra were computed from. raw data, after noise adaption and data adaption, from correlograms and using combinations of adaption and correlation: methods. This was done to employ not only the spectral differences of the events but also the temporal variation of energy and lack of it as a function of frequency. The optimum frequeney windows for spectral ratio and TMF were defined using stacked spectra of about 10 events from both classes. No single discriminant could classify all the events. Their performance varied significanfly for different stations, but on average the spectral discriminants had slightly higher discrimination capability than complexity. The distributions of all discriminants were studied and a group separation function was formed using an optimum set of discriminants. Instead of discriminant values their relative positions in the corresponding distributions of nuelear tests and earthquakes were used as inputs to the function. A weight for each discriminant was derived from the amount of overlap in the distributions of earthquakes and nuelear tests. All 75 events in the data set were correctly classified with the method. The testing was performed with a jack knife method to create an independent test data base

  2. Deciphering IR Excess Observed by the Spitzer Space Telescope in Short Period Interacting Cataclysmic Binaries

    Science.gov (United States)

    Chun, Howard; Brinkworth, Carolyn; Ciardi, David; Hoard, Don; Howell, Steve; Stefaniak, Linda; Thomas, , Beth

    2006-03-01

    During the first year of the Spitzer Space Telescope Observing Program for Students and Teachers, our team observed a small sample of short orbital period interacting white dwarf binaries. Our scientific investigation was aimed at detection and characterization of the low mass, cool, brown dwarf-like mass donors in these systems. We used the Infrared Array Camera to obtain photometric observations of the polars EF Eri, GG Leo, V347 Pav, and RX J0154.0-5947 at 3.6, 4.5, 5.8, and 8.0 microns. In all our targets, we detected excess emission in the 3-8 micron region over that expected from a brown dwarf alone. One of the exciting discoveries we made with our IRAC observations is that the star EF Eri was found to be unexpectedly bright in the mid-IR (compared to its 2MASS magnitudes). This fact highlights an opportunity for us to observe EF Eri with the IRS as a follow-up proposal. EF Eri has a flux level of ~700 ?Jy at 8 microns. Thus, we are asking for time to obtain IRS data for only this star, our brightest source. We plan to obtain SL1 (7.4-14.5 microns) and SL2 (5.2-8.7 microns) spectroscopy only. We know the IRAC fluxes so our integration toies are well constrained and the spectral region covered by SL1, SL2 will yield sufficient S/N to differentiate between cool dust (rising BB like spectrum with PAH and other molecular features allowing us to determine dust size, temperature, and disk extent) and a T type dwarf showing characteristic spectral signatures and a falling Rayleigh-Jeans tail.

  3. KELT-16b: A Highly Irradiated, Ultra-short Period Hot Jupiter Nearing Tidal Disruption

    Science.gov (United States)

    Oberst, Thomas E.; Rodriguez, Joseph E.; Colón, Knicole D.; Angerhausen, Daniel; Bieryla, Allyson; Ngo, Henry; Stevens, Daniel J.; Stassun, Keivan G.; Gaudi, B. Scott; Pepper, Joshua; Penev, Kaloyan; Mawet, Dimitri; Latham, David W.; Heintz, Tyler M.; Osei, Baffour W.; Collins, Karen A.; Kielkopf, John F.; Visgaitis, Tiffany; Reed, Phillip A.; Escamilla, Alejandra; Yazdi, Sormeh; McLeod, Kim K.; Lunsford, Leanne T.; Spencer, Michelle; Joner, Michael D.; Gregorio, Joao; Gaillard, Clement; Matt, Kyle; Dumont, Mary Thea; Stephens, Denise C.; Cohen, David H.; Jensen, Eric L. N.; Calchi Novati, Sebastiano; Bozza, Valerio; Labadie-Bartz, Jonathan; Siverd, Robert J.; Lund, Michael B.; Beatty, Thomas G.; Eastman, Jason D.; Penny, Matthew T.; Manner, Mark; Zambelli, Roberto; Fulton, Benjamin J.; Stockdale, Christopher; DePoy, D. L.; Marshall, Jennifer L.; Pogge, Richard W.; Gould, Andrew; Trueblood, Mark; Trueblood, Patricia

    2017-03-01

    We announce the discovery of KELT-16b, a highly irradiated, ultra-short period hot Jupiter transiting the relatively bright (V = 11.7) star TYC 2688-1839-1/KELT-16. A global analysis of the system shows KELT-16 to be an F7V star with {T}{eff}=6236+/- 54 K, {log}{g}\\star ={4.253}-0.036+0.031, [{Fe}/{{H}}]=-{0.002}-0.085+0.086, {M}\\star ={1.211}-0.046+0.043 {M}ȯ , and {R}\\star ={1.360}-0.053+0.064{R}ȯ . The planet is a relatively high-mass inflated gas giant with {M}{{P}}={2.75}-0.15+0.16{M}{{J}}, {R}{{P}}={1.415}-0.067+0.084{R}{{J}}, density {ρ }{{P}}=1.20+/- 0.18 g cm‑3, surface gravity {log} {g}{{P}}={3.530}-0.049+0.042, and {T}{eq}={2453}-47+55 K. The best-fitting linear ephemeris is {T}{{C}}=2457247.24791+/- 0.00019 {{BJD}}{TDB} and P=0.9689951+/- 0.0000024 day. KELT-16b joins WASP-18b, ‑19b, ‑43b, ‑103b, and HATS-18b as the only giant transiting planets with P disrupted in as little as a few ×105 years (for a stellar tidal quality factor of {Q}* \\prime ={10}5). Finally, the likely existence of a widely separated bound stellar companion in the KELT-16 system makes it possible that Kozai–Lidov (KL) oscillations played a role in driving KELT-16b inward to its current precarious orbit.

  4. First limits on the occurrence rate of short-period planets orbiting brown dwarfs

    Science.gov (United States)

    He, Matthias Y.; Triaud, Amaury H. M. J.; Gillon, Michaël

    2017-01-01

    Planet formation theories predict a large but still undetected population of short-period terrestrial planets orbiting brown dwarfs. Should specimens of this population be discovered transiting relatively bright and nearby brown dwarfs, the Jupiter-size and the low luminosity of their hosts would make them exquisite targets for detailed atmospheric characterization with JWST and future ground-based facilities. The eventual discovery and detailed study of a significant sample of transiting terrestrial planets orbiting nearby brown dwarfs could prove to be useful not only for comparative exoplanetology but also for astrobiology, by bringing us key information on the physical requirements and time-scale for the emergence of life. In this context, we present a search for transit-signals in archival time series photometry acquired by the Spitzer Space Telescope for a sample of 44 nearby brown dwarfs. While these 44 targets were not particularly selected for their brightness, the high precision of their Spitzer light curves allows us to reach sensitivities below Earth-sized planets for 75 per cent of the sample and down to Europa-sized planets on the brighter targets. We could not identify any unambiguous planetary signal. Instead, we could compute the first limits on the presence of planets on close-in orbits. We find that within a 1.28 d orbit, the occurrence rate of planets with a radius between 0.75 and 3.25 R⊕ is η TRAPPIST-1b systems would suggest, we estimate that 175 brown dwarfs need to be monitored in order to guarantee (95 per cent) at least one detection.

  5. Short (

    NARCIS (Netherlands)

    Telleman, Gerdien; den Hartog, Laurens

    2013-01-01

    Aim: This systematic review assessed the implant survival rate of short (<10 mm) dental implants installed in partially edentulous patients. A case report of a short implant in the posterior region have been added. Materials and methods: A search was conducted in the electronic databases of MEDLINE

  6. Short (

    NARCIS (Netherlands)

    Telleman, Gerdien; den Hartog, Laurens

    2013-01-01

    Aim: This systematic review assessed the implant survival rate of short (<10 mm) dental implants installed in partially edentulous patients. A case report of a short implant in the posterior region have been added. Materials and methods: A search was conducted in the electronic databases of MEDLINE

  7. Spatial characteristics of extreme rainfall over China with hourly through 24-hour accumulation periods based on national-level hourly rain gauge data

    Science.gov (United States)

    Zheng, Yongguang; Xue, Ming; Li, Bo; Chen, Jiong; Tao, Zuyu

    2016-11-01

    Hourly rainfall measurements of 1919 national-level meteorological stations from 1981 through 2012 are used to document, for the first time, the climatology of extreme rainfall in hourly through 24-h accumulation periods in China. Rainfall amounts for 3-, 6-, 12- and 24-h periods at each station are constructed through running accumulation from hourly rainfall data that have been screened by proper quality control procedures. For each station and for each accumulation period, the historical maximum is found, and the corresponding 50-year return values are estimated using generalized extreme value theory. Based on the percentiles of the two types of extreme rainfall values among all the stations, standard thresholds separating Grade I, Grade II and Grade III extreme rainfall are established, which roughly correspond to the 70th and 90th percentiles for each of the accumulation periods. The spatial characteristics of the two types of extreme rainfall are then examined for different accumulation periods. The spatial distributions of extreme rainfall in hourly through 6-h periods are more similar than those of 12- and 24-h periods. Grade III rainfall is mostly found over South China, the western Sichuan Basin, along the southern and eastern coastlines, and in the large river basins and plains. There are similar numbers of stations with Grade III extreme hourly rainfall north and south of 30°N, but the percentage increases to about 70% south of 30°N as the accumulation period increases to 24 hours, reflecting richer moisture and more prolonged rain events in southern China. Potential applications of the extreme rainfall climatology and classification standards are suggested at the end.

  8. A periodic foundation with rotational oscillators for extremely low-frequency seismic isolation: analysis and experimental verification

    Science.gov (United States)

    Huang, Jiankun; Shi, Zhifei; Huang, Weixin; Chen, Xinhua; Zhang, Zhiwei

    2017-03-01

    A new type of periodic foundation (PF) with rotational oscillators was developed, and its locally resonant attenuation feature was analyzed numerically and experimentally. The proposed PF was composed of a concrete matrix in which local resonators consisting of steel cores with rubber linkers were attached. Finite element method was employed to comprehensively investigate influences of material and geometrical parameters on the attenuation zones. Furthermore, a scaled PF was fabricated and shake tests were performed. The locally resonant mechanism within the rotational resonator can produce extremely low-frequency wave-forbidding capability. The results demonstrated that a PF can isolate seismic waves with frequencies lower than 10 Hz, sufficient to serve as a seismic isolation foundation for civil engineering structures. This kind of foundation system opens up new perspectives for the development of seismic isolation foundations for low-frequency applications.

  9. Negative Magnetoresistance in Silicon Doped AlAs-GaAs Short Period Superlattices

    Science.gov (United States)

    Gougam, A. B.; Sicart, J.; Robert, J. L.

    1997-01-01

    We report the negative magnetoresistance effect observed in GaAs-AlAs short period superlattices doped selectively in GaAs or in AlAs or doped uniformly. This doping technique introduces deep donor states with different thermal activation energies. Consequently, the low temperature electron concentration is different in samples doped at the same silicon concentration. We find the magnetic correction to the conductivity increasing with the free carrier density. The low magnetic field data are interpreted in the framework of a weak localization model derived from the Kawabata theory in 3D anisotropic systems. The theory of effective mass in superlattices is applied and we find that the inelastic scattering time does not depend on the doping modulation. Nous présentons des résultats de magnétorésistance négative obtenus avec des superréseaux à courte période de GaAs-AlAs dopés au silicium sélectivement dans GaAs ou AlAs et uniformément dopés. Ce type de dopage permet d'introduire des niveaux donneurs d'énergie d'activation thermique différents. Ceci permet d'obtenir à basse température des concentrations d'électrons différentes à partir d'une concentration initiale de dopant identique pour tous les échantillons. Nous mettons ainsi en évidence une correction magnétique à la conductivité qui augmente avec la densité de porteurs libres. Les mesures à faible champ sont interprétées en termes de faible localisation à partir du modèle de Kawabata 3D dans lequel l'anisotropie de masse effective du superréseau est introduite. Nous trouvons que le temps de diffusion inélastique ne dépend pas de la modulation de dopage.

  10. APPLICATION OF EXTREME VALUE THEORY AND FUNDAMENTAL ANALYSIS IN LONG-SHORT STRATEGIES: AN ANALYSIS OF PAIR TRADINGS IN THE BRAZILIAN MARKET

    Directory of Open Access Journals (Sweden)

    Danilo Soares Monte-Mor

    2014-09-01

    Full Text Available In recent decades, the number of funds has increased which aim to explore market inefficiencies through arbitrage strategies, among which the long-short strategy stands out. A large part of the analyses used to obtain the pair tradings, however, does not consider the extreme deviations that exist in the interdependence process between the assets involved and the firms’ operational quality indicators. The Extreme Value Theory and Fundamental Analysis were used in this study to model the series of the asset pair price indices obtained based on the accounting indicator structure proposed by Piotroski (2000. These approaches permitted considering companies with positive signs of profitability, an operational capital structure and efficiency, besides distributions that are capable of capturing the extreme co-movements associated with the selected pair tradings. Based on this model, a new quantitative approach was created for the long-short strategy, called the GEV Long-Short. The obtained results suggest that the best adjustment of the extreme quantiles through the extreme value distribution can provide more refined probabilistic support for the return to the average to justify the possibility of long-short arbitrage.

  11. Variable stars in Leo A : RR Lyrae stars, short-period cepheids, and implications for stellar content

    NARCIS (Netherlands)

    Dolphin, AE; Saha, A; Claver, J; Skillman, ED; Cole, AA; Gallagher, JS; Tolstoy, E; Dohm-Palmer, RC; Mateo, M

    2002-01-01

    We present the results of a search for short-period variable stars in Leo A. We have found 92 candidate variables, including eight candidate RR Lyrae stars. From the RR Lyrae stars, we measure a distance modulus of (m - M)(0) = 24.51 +/- 0.12, or 0.80 +/- 0.04 Mpc. This discovery of RR Lyrae stars c

  12. Assessing the potential impacts of climate change on return periods of hydrological extremes in the Illinois River watershed of the Midwestern United States

    Science.gov (United States)

    Chien, H.; Yeh, P. J. F.; Knouft, J.

    2014-12-01

    As the Earth's climate is predicted to change significantly in terms of warmer temperature and higher precipitation extremes during this century due to the increased combustion of fossil fuels, accurate estimations of the frequencies of future hydrological extremes are important to understanding the potential impacts of changes in climate on water resources management, particularly in accessing flood risk. The goal of this study is to use the Soil and Water Assessment Tool (SWAT), a distributed landscape-scale hydrological model, to predict current streamflow and the potential impacts of climate change on future stream flows in the Illinois River watershed in the Midwestern United States. Subsequently Gumbel distribution (Extreme Value Type Ⅰ) is fitted to the annual maxima simulated streamflow to derive a number of return periods of future hydrological extremes. The question in this study is: How do the return periods of future hydrological extremes change under future climate change scenarios and what factors cause the change? Daily simulated future streamflow from 2046-2065 and 2081-2100 are simulated using SWAT model based on nine separate downscaled global climate models (GCM) with three emissions scenarios. SWAT model predictions generally indicate that annual streamflow will likely decrease due to warmer temperatures. Based on the simulated daily streamflow, probability models for annual maxima flows frequency analysis are developed using Gumbel distribution and the values of hydrological extremes for different return periods including 50, 100, 200, 500, 1000 years are derived. The change of return periods of hydrological extremes and the implications will be discussed.

  13. An old male patient with paroxysmal chest distress,shortness of breath and edema of both lower extremities (the 27th case)

    Institute of Scientific and Technical Information of China (English)

    陈琪

    2008-01-01

    @@ The patient,a 78-year-old male,was admitted to the hospital on Nov.15,2007 because of paroxysmal chest distress and shortness of breath for 11years and edema of lower extremities for 3 days.The patient began to suffer from paroxysmal chest distress and shortness of breath after exertion in 1997,then these symptoms recurred frequently,which lasted 10 min to several hours.

  14. Assessing spatial patterns of extreme droughts associated to return periods from observed dataset: Case study of Segura River Basin (Spain)

    Science.gov (United States)

    García Galiano, Sandra G.; Diego Giraldo Osorio, Juan

    2013-04-01

    In basins of South-eastern Spain, such as the Segura River Basin (SRB), a strong decrease in runoff from the end of the 1970s has been observed. In the SRB, due to intensive reforestation aimed at halting desertification and erosion, added to climate variability and change, the default assumption of stationarity in water resources systems cannot be guaranteed. Therefore there is an important need for improvement in the ability of monitoring and predicting the impacts associated with the change of hydrologic regime. It is thus necessary to apply non-stationary probabilistic models, which are able to reproduce probability density functions whose parameters vary with time. From a high-resolution daily gridded rainfall dataset of more than 50 years (1950-2007 time period), the spatial distribution of lengths of maximum dry spells for several thresholds are assessed, applying GAMLSS (Generalized Additive Models for Location Scale and Shape) models at grid site. Results reveal an intensification of extreme drought events in some headbasins of the SRB important for water supply. The identification of spatial patterns of drought hazards at basin scale, associated to return periods, contribute to designing strategies of drought contingency preparedness and recovery operations, which are the leading edge of adaptation strategies.

  15. An extreme planetary system around HD219828. One long-period super Jupiter to a hot-neptune host star

    CERN Document Server

    Santos, N C; Faria, J P; Rey, J; Correia, A C M; Laskar, J; Udry, S; Adibekyan, V; Bouchy, F; Delgado-Mena, E; Melo, C; Dumusque, X; Hébrard, G; Lovis, C; Mayor, M; Montalto, M; Mortier, A; Pepe, F; Figueira, P; Sahlmann, J; Ségransan, D; Sousa, S G

    2016-01-01

    With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. We present a full investigation of the HD219828 system, a bright metal-rich star for which a hot neptune has previously been detected. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD219828. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. We announce the discovery of a long period (P=13.1years) massive (msini=15.1MJup) companion (HD219828c) in a very eccentric orbit (e=0.81). The same data confirms the existence of a hot-neptune, HD219828b, with a minimum mass of 21 MEarth and a period of 3.83days. The dynamical analysis shows that the system is stable. The HD219828 system is extreme and unique in several aspects. First, among all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like H...

  16. The Description of Extremely Short Pulses in Non-Resonant Media in Frame of Maxwell-Duffing-Type Models

    Science.gov (United States)

    Kazantseva, Elena V.

    The propagation of extremely short pulses of electromagnetic field (electromagnetic spikes) is considered in the framework of a model where the material medium is represented by anharmonic oscillators with cubic nonlinearities (Duffing model) and waves can propagate in both directions. The system of total Maxwell-Duffing equations admits two families of exact analytical solutions in the form of solitary waves. The single-cycle electromagnetic pulse propagation in a medium whose dispersion and nonlinear properties are described by the cubic-quintic Duffing model (oscillator with third- and fifth-order anharmonicity). A system of equations governing the evolution of a unidirectional electromagnetic wave is analyzed without using the approximation of slowly varying envelopes. Three types of solutions of this system describing stationary propagation of a pulse in such a medium are found. When the signs of the anharmonicity constants are different, the amplitude of a steady-state pulse is limited, but its energy may grow on account of an increase in its duration.

  17. Spectral analysis of short period of K indices registered in Huancayo Geomagnetic Observatory

    CERN Document Server

    Rosales, Domingo

    2016-01-01

    Wavelet spectral analysis is applied to the daily indices K (SK) registered in Huancayo geomagnetic observatory from 2000.0 to 2015.0, it has become possible to identify predominant periodic components with a confidence level of 95%. In particular we have investigated the periodicity of 27.0 days and its 13.5, 9.0 and 6.8 harmonics, related to the fundamental period of solar rotation effects. A special analysis registered on periods of 59.0 days might be related to the double period of 29.53 days corresponding to the synodic month. The manifestation of the periods of 182.6, 365 and 730 days corresponding to the harmonics of the seasonal variation of the annual cycle is also observed. An important observation is that the global predominant periods registered 6.8 and 9.0 days, in the years 2009, 2013 and 2014 its effect is too small or null, those periods corresponds to the minimum and maximum solar activity. On the other hand, it is observed that the order of predominance of the harmonic period solar rotation ...

  18. The OmegaWhite Survey for short period variable stars - II. An overview of results from the first four years

    Science.gov (United States)

    Toma, R.; Ramsay, G.; Macfarlane, S.; Groot, P. J.; Woudt, P. A.; Dhillon, V.; Jeffery, C. S.; Marsh, T.; Nelemans, G.; Steeghs, D.

    2016-11-01

    OmegaWhite is a wide-field, high cadence, synoptic survey targeting fields in the southern Galactic plane, with the aim of discovering short period variable stars. Our strategy is to take a series of 39 s exposures in the g band of a 1 deg2 of sky lasting 2 h using the OmegaCAM wide field imager on the VLT Survey Telescope (VST). We give an overview of the initial 4 yr of data which covers 134 deg2 and includes 12.3 million light curves. As the fields overlap with the VLT Survey Telescope Hα Photometric Survey of the Galactic plane and Bulge (VPHAS+), we currently have ugriHα photometry for ˜1/3 of our fields. We find that a significant fraction of the light curves have been affected by the diffraction spikes of bright stars sweeping across stars within a few dozen of pixels over the two hour observing time interval due to the alt-az nature of the VST. We select candidate variable stars using a variety of variability statistics, followed by a manual verification stage. We present samples of several classes of short period variables, including: an ultra compact binary, a DQ white dwarf, a compact object with evidence of a 100 min rotation period, three CVs, one eclipsing binary with an 85 min period, a symbiotic binary which shows evidence of a 31 min photometric period, and a large sample of candidate δ Sct type stars including one with a 9.3 min period. Our overall goal is to cover 400 deg2, and this study indicates we will find many more interesting short period variable stars as a result.

  19. Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period

    Directory of Open Access Journals (Sweden)

    Burke DT

    2013-10-01

    Full Text Available David T Burke,1 David Tran,1 Di Cui,1 Daniel P Burke,2 Samir Al-Adawi,3 Atsu SS Dorvlo41Emory University Medical School, Atlanta, GA, USA; 2Georgia College and State University, GA, USA; 3Department of Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; 4Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, Muscat, OmanAbstract: In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings.Keywords: Anatoly Gravitational System, weight training, musculoskeletal system

  20. Transient Supersaturation Supports Drug Absorption from Lipid-Based Formulations for Short Periods of Time, but Ongoing Solubilization Is Required for Longer Absorption Periods.

    Science.gov (United States)

    Crum, Matthew F; Trevaskis, Natalie L; Pouton, Colin W; Porter, Christopher J H

    2017-02-06

    The current studies sought to explore the impact of drug supersaturation and precipitation during the dispersion and digestion of lipid-based formulations (LBFs), on in vivo absorption using a coupled in vitro digestion-in vivo perfusion absorption model. Fenofibrate absorption was evaluated from a number of LBFs with different solubilization and supersaturation capacities, and conditions at the absorptive membrane manipulated by changing perfusion conditions, intestine segment lengths, and by the conduct of experiments in the presence or absence of suspended/precipitated drug. LBF dispersion and digestion resulted in varying periods of supersaturation across the different formulations. Even fleeting (5-10 min) periods of supersaturation were able to drive flux across a perfused 10 cm intestinal segment for up to 60 min, although over longer infusion periods (60-80 min) flux dropped in the absence of ongoing drug solubilization and supersaturation. In contrast, the presence or absence of precipitated/suspended drug, had little impact on drug flux. When perfused intestinal segment lengths were extended, the role of initial supersaturation was attenuated and ongoing solubilization conditions became the primary driver of absorptive flux. The data suggest that for highly permeable drugs such as fenofibrate, a short period of supersaturation at the absorptive membrane may be sufficient to drive absorptive drug flux in spite of significant drug precipitation on formulation dispersion or digestion in vitro. In contrast, where longer periods of absorption are required, for example, at higher doses, the requirement for ongoing solubilization and supersaturation becomes more apparent.

  1. Short Period Logistics Integrating: a Model for Vendors Evaluating and Selecting

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Vendors'Evaluating and Selecting is one study focu s in SCM and VMO. It is one of the very important operations management and can ad vance to implement the strategic aims. With the increase in use of total quality management and just-in-time concepts by a wide range of firms, the vendor sel ection question has become extremely important. It is necessary for firms to tak e part in the global competition and global manufacture. There are some decision -making techniques which can be used for evaluating and...

  2. A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Jacobs, Robert A; Bonne, Thomas Christian

    2016-01-01

    not increase in response to training. Both before and after the HIT-period fast V̇O2 kinetics (low τ values) was associated with large values for ETFP, electron transport system capacity (ETS) and electron flow specific to complex II (CIIP) (P...The aim of the present study was to examine whether improvements in pulmonary V̇O2 kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age: 26 ± 2; mean ± SD) performed six HIT...

  3. Born Dry in the Photo-Evaporation Desert: Kepler's Ultra-Short-Period Planets Formed Water-Poor

    CERN Document Server

    Lopez, Eric D

    2016-01-01

    Recent surveys have uncovered an exciting new population of ultra-short-period (USP) planets with orbital periods less than a day. These planets typically have radii 2 Earth radii today, which is inconsistent with the observed evaporation desert, indicating that most USP planets likely formed from water-poor material within the snow-line. Finally, I examine the special case of 55 Cancri e and its possible composition in the light of recent observations, and discuss the prospects for further characterizing this population with future observations.

  4. Reconstruction of 2D seismic wavefield from Long-Period Seismogram and Short-Period Seismogram Envelope by Seismic Gradiometry applied to the Hi-net Array

    Science.gov (United States)

    Maeda, Takuto; Nishida, Kiwamu; Takagi, Ryota; Obara, Kazushige

    2016-04-01

    The high-sensitive seismograph network (Hi-net) operated by National Research Institute for Earth Science and Disaster Prevention (NIED) has about 800 stations with average separation of 20 km all over the Japanese archipelago. Although it is equipped with short-period seismometers, we also can observe long-period seismic wave up to 100 s in periods for significantly large earthquakes. In this case, we may treat long-period seismic waves as a 2D wavefield with station separations shorter than wavelength rather than individual traces at stations. In this study, we attempt to reconstruct 2D wavefield and obtain its propagation properties from seismic gradiometry (SG) method. The SG estimates the wave amplitude and its spatial derivative coefficients from discrete station record by the Taylor series approximation with an inverse problem. By using spatial derivatives in horizontal directions, we can obtain properties of propagating wave packet such as the arrival direction, slowness, geometrical spreading and radiation pattern. In addition, by using spatial derivatives together with free-surface boundary condition, we may decompose the vector elastic 2D wavefield estimated by the SG into divergence and rotation components. First, we applied the seismic gradiometry to a synthetic long-period (20-50 s) seismogram dataset computed by numerical simulation in realistic 3D medium at the Hi-net station layout as a feasibility test. We confirmed that the wave amplitude and its spatial derivatives are very well reproduced with average correlation coefficients higher than 0.99 in this period range. Applications to a real large earthquakes show that the amplitude and phase of the wavefield are well reconstructed with additional information of arrival direction and its slowness. The reconstructed wavefield contained a clear contrast in slowness between body and surface waves, regional non-great-circle-path wave propagation which may be attributed to scattering. Slowness

  5. Short-Wavelength Free-Electron Lasers with Periodic Plasma Structures

    NARCIS (Netherlands)

    Bazylev, V. A.; Schep, T. J.; Tulupov, A. V.

    1994-01-01

    Concepts of compact free-electron lasers that are based on beam-plasma interactions and that operate in the vacuum ultraviolet and x-ray wavelength ranges are discussed. Coherent radiation can not only be produced by periodic transverse motions of an electron beam, but also by its longitudinal motio

  6. Propagation of short-period gravity waves at high-latitudes during the MaCWAVE winter campaign

    Directory of Open Access Journals (Sweden)

    K. Nielsen

    2006-07-01

    Full Text Available As part of the MaCWAVE (Mountain and Convective Waves Ascending Vertically winter campaign an all-sky monochromatic CCD imager has been used to investigate the properties of short-period mesospheric gravity waves at high northern latitudes. Sequential measurements of several nightglow emissions were made from Esrange, Sweden, during a limited period from 27–31 January 2003. Coincident wind measurements over the altitude range (~80–100 km using two meteor radar systems located at Esrange and Andenes have been used to perform a novel investigation of the intrinsic properties of five distinct wave events observed during this period. Additional lidar and MSIS model temperature data have been used to investigate their nature (i.e. freely propagating or ducted. Four of these extensive wave events were found to be freely propagating with potential source regions to the north of Scandinavia. No evidence was found for strong orographic forcing by short-period waves in the airglow emission layers. The fifth event was most unusual exhibiting an extensive, but much smaller and variable wavelength pattern that appeared to be embedded in the background wind field. Coincident wind measurements indicated the presence of a strong shear suggesting this event was probably due to a large-scale Kelvin-Helmholtz instability.

  7. The multi-band CCD photometric investigation of short-period eclipsing binary V1044 Her

    Science.gov (United States)

    Lu, Hongpeng; Zhang, Liyun; Han, Xianming L.; Pi, Qingfeng; Wang, Daimei

    2016-10-01

    We present new CCD photometric observations of V1044 Her obtained on May 22, 23 and 24, 2015. From our data, we derived five new light curve minimum times. Combining our new results with previously available CCD light minimum times, we derived an updated ephemeris and discovered that the period of this binary system exhibits an oscillation. The cyclic variation may be caused by the light-time effect via the presence of a third body or magnetic activity cycle. We calculated the corresponding period of the third body to be 14.1 ± 1.4 years or magnetic cycle to be 12.2 ± 0.7 years. We analyzed our new asymmetric light curves to obtain photometric solutions and starspot parameters using the Wilson and Devinney program. The final results show that V1044 Her is a contact binary system with a degree of contact factor f = 3.220(± 0.002)%.

  8. Mt. Suhora M dwarf survey - Detection of eight short-period variable stars

    CERN Document Server

    Machado, L Fox; Winiarski, M; Krzesiński, J; Dróżdz, M

    2011-01-01

    The Mt. Suhora M\\,dwarf survey searching for pulsations in low mass main sequence stars has acquired CCD photometry of 46 M\\,dwarf stars during the first year of the project (Baran et al 2011). As a by-product of this search hundreds field stars have been checked for variability. This paper presents our initial result of a search for periodic variables in field stars observed in the course of the survey. On the basis of the periodicity and the shape of the light curves, eight new variables has been detected, among which five are $\\delta$ Scuti stars and three likely RR Lyrae stars. Although variation in one of the stars has been previously detected, it was classified incorrectly. To support our classification, in August 2010, we performed spectroscopic observations to derive spectral types and luminosity classes for all eight variable stars.

  9. Observer variations in short period spectral analysis of heart rate variability.

    Science.gov (United States)

    van Schelven, L J; Oey, P L; Klein, I H; Barnas, M G; Blankestijn, P J; Wieneke, G H

    2000-03-15

    25% of the corresponding mean LF/HF ratio. The smallest interobserver variations were found for the 'fixed frequency' method. The data showed that it is advantageous to select the 3-min ECG periods but not to select the frequency regions. Selection of the latter led to an increase in interobserver variation. The results of this study give a realistic impression of the intrasubject and interobserver variation to be expected when measuring the LF/HF ratio. This variation is considerable.

  10. Influence of cosmic radiation on aerosol and cloud formation over short time periods

    DEFF Research Database (Denmark)

    Bondo, Torsten

    This thesis describes a study of Forbush decrease events. These are rapid decreases in the cosmic ray intensity in the Earth’s atmosphere, which are caused by a temporary increased magnetic shielding at Earth due to solar eruptions. The aim is to investigate how these transient ionization phenomena...... for cosmic rays. A list of the ionization change in the troposphere of the strongest Forbush decreases as compared to the ionization change over the solar cycle is calculated and indicates that only a few events induce ionization changes comparable to the solar cycle. Studies of recently available high...... gas concentration on aerosol and cloud optical properties over short time. The model is used to examine experimental efforts at DTU Space on the role of ions in nucleation, as well as it is used to investigate observational data on Forbush decreases in aerosols. The model confirms the existence...

  11. Short communication: study of immune parameters in three Greek dairy sheep breeds during the periparturient period.

    Science.gov (United States)

    Theodorou, G; Fragou, S; Chronopoulou, R; Kominakis, A; Rogdakis, E; Politis, I

    2007-12-01

    The objective of the present study was to evaluate whether immunosuppression occurs in 3 different Greek dairy sheep breeds during the periparturient period. A total of 33 ewes from 3 breeds [i.e., the low-producing Boutsiko breed (n = 11), which is highly adaptable to harsh environments; the high-producing but environmentally fragile Chios breed (n = 11); and an intermediate synthetic breed (50% Boutsiko, 25% Arta, and 25% Chios, n = 11)] were used. Blood samples were collected at 18 and 2 d before parturition and at 15 d after parturition. Total cell-associated and membrane-bound urokinase plasminogen activator (U-PA) activity, free U-PA binding sites on cellular membranes, and superoxide anion (SA) production by activated phagocytes were determined. Results indicated that all immune parameters measured remained constant during the periparturient period for the Boutsiko breed. In contrast, there were reductions in total cell-associated and membrane-bound U-PA activity by both monocytes-macrophages and neutrophils and in SA production by monocytes-macrophages at d 2 before parturition for the Chios breed. In the synthetic breed, there were reductions in total cell-associated and membrane-bound U-PA activity by monocytes-macrophages and in SA production by both monocytes-macrophages and neutrophils at d 15 after parturition. Thus, mild immunosuppression during the periparturient period was observed in the 2 breeds with the highest milk production.

  12. The ACS LCID Project. VIII. The short-period Cepheids of Leo A

    CERN Document Server

    Bernard, Edouard J; Gallart, Carme; Fiorentino, Giuliana; Cassisi, Santi; Aparicio, Antonio; Cole, Andrew A; Drozdovsky, Igor; Hidalgo, Sebastian L; Skillman, Evan D; Stetson, Peter B; Tolstoy, Eline

    2013-01-01

    We present the results of a new search for variable stars in the Local Group dwarf galaxy Leo A, based on deep photometry from the Advanced Camera for Surveys onboard the Hubble Space Telescope. We detected 166 bona fide variables in our field, of which about 60 percent are new discoveries, and 33 candidate variables. Of the confirmed variables, we found 156 Cepheids, but only 10 RR Lyrae stars despite nearly 100 percent completeness at the magnitude of the horizontal branch. The RR Lyrae stars include 7 fundamental and 3 first-overtone pulsators, with mean periods of 0.636 and 0.366 day, respectively. From their position on the period-luminosity (PL) diagram and light-curve morphology, we classify 91, 58, and 4 Cepheids as fundamental, first-overtone, and second-overtone mode Classical Cepheids (CC), respectively, and two as population II Cepheids. However, due to the low metallicity of Leo A, about 90 percent of the detected Cepheids have periods shorter than 1.5 days. Comparison with theoretical models ind...

  13. Short apsidal period of three eccentric eclipsing binaries discovered in the Large Magellanic Cloud

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kyeongsoo; Lee, Chung-Uk; Kim, Seung-Lee [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Kang, Young-Woon [Department of Astronomy and Space Science, Sejong University, Seoul 143-747 (Korea, Republic of)

    2014-06-01

    We present new elements of apsidal motion in three eccentric eclipsing binaries located in the Large Magellanic Cloud. The apsidal motions of the systems were analyzed using both light curves and eclipse timings. The OGLE-III data obtained during the long period of 8 yr (2002-2009) allowed us to determine the apsidal motion period from their analyses. The existence of third light in all selected systems was investigated by light curve analysis. The O – C diagrams of EROS 1018, EROS 1041, and EROS 1054 were analyzed using the 30, 44, and 26 new times of minimum light, respectively, determined from full light curves constructed from EROS, MACHO, OGLE-II, OGLE-III, and our own observations. This enabled a detailed study of the apsidal motion in these systems for the first time. All of the systems have a significant apsidal motion below 100 yr. In particular, EROS 1018 shows a very fast apsidal period of 19.9 ± 2.2 yr in a detached system.

  14. The Short Rotation Period of Hi'iaka, Haumea's Largest Satellite

    CERN Document Server

    Hastings, Danielle M; Fabrycky, Daniel C; Burkhart, Luke D; Fuentes, Cesar; Margot, Jean-Luc; Brown, Michael E; Holman, Matthew

    2016-01-01

    Hi'iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi'iaka to be ~9.8 hrs (double-peaked). This is ~120 times faster than its orbital period, creating new questions about the formation of this system and possible tidal evolution. The rapid rotation suggests that Hi'iaka could have a significant obliquity and spin precession that could be visible in light curves within a few years. We then turn to an investigation of what we learn about the (presently unclear) formation of the Haumea system and family based on this unexpectedly rapid rotation rate. We explore the importance of the initial semi-major axis and rotation period in tidal evolution theory and find they strongly influence the time required to despin to synchronous rotation, relevant to understanding a wide variety of satellite and binary systems. We find that despinning tides do ...

  15. Short-period surface-wave phase velocities across the conterminous United States

    Science.gov (United States)

    Ekström, G.

    2017-09-01

    Surface-wave phase-velocity maps for the full footprint of the USArray Transportable Array (TA) across the conterminous United States are developed and tested. Three-component, long-period continuous seismograms recorded on more than 1800 seismometers, most of which were deployed for 18 months or longer, are processed using a noise cross-correlation technique to derive inter-station Love and Rayleigh dispersion curves at periods between 5 and 40 s. The phase-velocity measurements are quality controlled using an automated algorithm and then used in inversions for Love and Rayleigh phase-velocity models at discrete periods on a 0.25°-by-0.25° pixel grid. The robustness of the results is examined using comparisons of maps derived from subsets of the data. A winter-summer division of the cross-correlation data results in small model differences, indicating relatively minor sensitivity of the results to seasonal variations in the distribution of noise sources. Division of the dispersion data based on inter-station azimuth does not result in geographically coherent model differences, suggesting that azimuthal anisotropy at the regional scale is weak compared with variations in isotropic velocities and does not substantially influence the results for isotropic velocities. The phase-velocity maps and dispersion measurements are documented and made available as data products of the 10-year-long USArray TA deployment.

  16. Risk of lower extremity arterial disease in a cohort of workers occupationally exposed to ionizing radiation over a prolonged period

    Energy Technology Data Exchange (ETDEWEB)

    Azizova, Tamara V.; Bannikova, Maria V.; Grigorieva, Evgenia S.; Bagaeva, Yaroslava P.; Azizova, Elena V. [Southern Urals Biophysics Institute, Ozyorsk Chelyabinsk Region (Russian Federation)

    2016-05-15

    In this study the incidence risk of lower extremity arterial disease (LEAD; international classification of diseases version 9 code 440.2) was assessed in a cohort of workers occupationally exposed to radiation over a prolonged period. The study cohort includes 22,377 workers of the Mayak Production Association (25 % of whom are females) first employed at one of the main facilities in 1948-1982 and followed up to the end of 2008. Dose estimates used in the study are provided by Mayak Worker Dosimetry System 2008. The mean total dose from external gamma-rays is 0.54 Gy for males and 0.44 Gy for females. The mean absorbed liver dose from internal alpha-radiation due to incorporated plutonium is 0.23 Gy in males and 0.44 Gy in females. Relative risks and excess relative risks per unit dose (ERR/Gy) are calculated based on maximum likelihood. A total of 943 cases of LEAD are registered in the study cohort during the follow-up of 512,801 person-years. A significant association of LEAD incidence with total dose from external gamma-rays (based on a linear model) was revealed, and the ERR/Gy is 0.27 (95 % confidence interval (CI) 0.11; 0.48). It turned out that a linear-exponential model provides a better fit of the data (∇AIC = 9.957). Inclusion of an adjustment for internal alpha-radiation dose resulted in the reduction of the ERR/Gy to 0.19 (95 % CI 0.05; 0.39), but the risk remains significant. No association of LEAD incidence with dose from internal alpha-radiation was found in the study worker cohort. It is concluded that this study provides evidence for an association of LEAD incidence with dose from external gamma-rays taking non-radiation factors into account. (orig.)

  17. First Kepler results on compact pulsators - V. Slowly pulsating subdwarf B stars in short-period binaries

    DEFF Research Database (Denmark)

    Kawaler, Stephen D.; Reed, Michael D.; Østensen, Roy H.

    2010-01-01

    The survey phase of the Kepler Mission includes a number of hot subdwarf B (sdB) stars to search for non-radial pulsations. We present our analysis of two sdB stars that are found to be g-mode pulsators of the V1093 Her class. These two stars also display the distinct irradiation effect typical...... of sdB stars with a close M-dwarf companion with orbital periods of less than half a day. Because the orbital period is so short, the stars should be in synchronous rotation, and if so, the rotation period should imprint itself on the multiplet structure of the pulsations. However, we do not find clear...... evidence for such rotational splitting. Though the stars do show some frequency spacings that are consistent with synchronous rotation, they also display multiplets with splittings that are much smaller. Longer-duration time series photometry will be needed to determine if those small splittings...

  18. The eccentric short-period orbit of the supergiant fast X-ray transient HD 74194 (=LM Vel)

    CERN Document Server

    Gamen, R; Walborn, N R; Morrell, N I; Arias, J I; Apellániz, J Maíz; Sota, A; Alfaro, E J

    2015-01-01

    Aims. We present the first orbital solution for the O-type supergiant star HD 74194, which is the optical counterpart of the supergiant fast X-ray transient IGR J08408-4503. Methods. We measured the radial velocities in the optical spectrum of HD 74194, and we determined the orbital solution for the first time. We also analysed the complex H{\\alpha} profile. Results. HD 74194 is a binary system composed of an O-type supergiant and a compact object in a short-period ($P=9.5436\\pm0.0002$ d) and high-eccentricity ($e=0.63\\pm0.03$) orbit. The equivalent width of the H{\\alpha} line is not modulated entirely with the orbital period, but seems to vary in a superorbital period ($P=285\\pm10$ d) nearly 30 times longer than the orbital one.

  19. Photometric study of the short-period RS CVn eclipsing binary DV Psc

    CERN Document Server

    Pi, Qingfeng; Li, Zhongmu; Sang, Hongyan; Zhu, Zhongzhong

    2012-01-01

    We present our new photometry of DV Psc obtained in 2010 and 2011, and new spectroscopic observation on Feb. 14, 2012. During our observations, three flare-like events might be detected firstly in one period on DV Psc. The flare rate of DV Psc is about 0.017 flares per hour. Using Wilson-Devinney program, we derived the preliminary starspot parameters. Moreover, the magnetic cycle is 9.26(+/-0.78) year analyzed by variabilities of Max.I - Max.II.

  20. Neuromuscular Responses to Short-Term Resistance Training With Traditional and Daily Undulating Periodization in Adolescent Elite Judoka.

    Science.gov (United States)

    Ullrich, Boris; Pelzer, Thiemo; Oliveira, Sergio; Pfeiffer, Mark

    2016-08-01

    Ullrich, B, Pelzer, T, Oliveira, S, and Pfeiffer, M. Neuromuscular responses to short-term resistance training with traditional and daily undulating periodization in adolescent elite judoka. J Strength Cond Res 30(8): 2083-2099, 2016-The influence of different periodization models on neuromuscular outcomes after short-term strength training periods has not been examined in adolescent athletes. Eleven elite judoka (age: 14.8 ± 0.6 years, height: 163.2 ± 7.5 cm, body mass: 57.3 ± 11.1 kg, 5 boys/6 girls, and strength training experience: 2.7 ± 1.1 years) performed two 4-week strength training mesocycles (each with 12 sessions) with either traditional (TP) or daily undulating (DUP) periodization. Both mesocycles were separated by a 7-week washout period and added to the regular judo training. Strength training was performed as lifting and lowering of weights using squats, knee flexion curl, clean & jerk, snatch, bench press, barbell bench pull, and lat pull-down. The mesocycles were equated for the number of repetitions and different intensity zones (50-90% of 1 repetition maximum [1RM]), addressing the optimization of strength, power, or velocity. Laboratory and 1RM testing was carried out 2 times during the baseline (T1 and T2), after the TP mesocycle (T3), after the washout period (T4), and after the DUP mesocycle (T5). Isometric knee extensor and knee flexor maximum voluntary contractive capacity (MVC), electromyographic-estimated neural drive of the quadriceps femoris, vastus lateralis (VL) muscle architecture, and 1RMs of all training exercises were measured. ANOVA revealed moderate (5.5-13.5%) but significant (p ≤ 0.05) temporal gains in knee extensor MVC, 1RMs, and VL architecture during both the mesocycles. Wilcoxon tests detected no significant differences for the percentage changes of any outcome between the mesocycles. For adolescent judoka, TP and DUP were equally adept in improving neuromuscular outcomes during short-term training periods.

  1. The Short Period End of the Distribution of Contact Binary Stars

    CERN Document Server

    Molnar, Lawrence A; Steenwyk, Steven D

    2013-01-01

    Contact binary systems (also known as W UMa systems) consist of a pair of hydrogen-burning dwarf stars orbiting each other so closely that they share a common envelope. Although they are relatively common, there is as yet no established consensus on the principle evolutionary questions surrounding them: how do they form, how do they evolve over time, what do they become? One observational clue to their evolutionary history has been the abrupt termination of the orbital period distribution around 5.2 hours. We have undertaken an observational study of this by 1) discovery of fast W UMa systems in our Calvin-Rehoboth Observatory data archive, 2) follow-up with the Calvin-Rehoboth Observatory of candidate fast systems from the Catalina Sky Survey, and 3) follow-up of other reports of potentially fast systems in other recently published surveys. We find the follow-up to have been particularly important as many surveys taken for other purposes lead to ambiguous or incorrect claims for periods less than five hours....

  2. The First Photometric Study of the Short-period Shallow Contact System LO Comae

    Science.gov (United States)

    Zhang, Y.; Han, Q. W.; Liu, J. Z.

    2016-12-01

    In this paper, the first complete photometric light curves in the B, V, and R passbands for an eclipsing binary LO Com are presented, and the photometric solution for the LO Com is derived by analyzing these light curves by using the Wilson and Devinney code. From the photometric solution, it is found that the LO Com is a W-type W UMa binary with a mass ratio of q={m}2/{m}1=2.478 and a contact degree of f=(3.2+/- 0.25) % . By combining the two new minimum times with those published earlier in the literature, we have found that the (O - C) curve shows a downward parabolic variation corresponding to a long-term decrease in the orbital period with a rate of {{d}}P/{{d}}t=-1.18× {10}-7 days yr-1. This long-term decrease in its orbital period may be caused by mass transfer from the more massive component to the less massive one.

  3. Non-thyroid cancer in Northern Ukraine in the post-Chernobyl period: Short report.

    Science.gov (United States)

    Hatch, M; Ostroumova, E; Brenner, A; Federenko, Z; Gorokh, Y; Zvinchuk, O; Shpak, V; Tereschenko, V; Tronko, M; Mabuchi, K

    2015-06-01

    The Chernobyl nuclear power plant accident in Ukraine in 1986 led to widespread radioactive releases into the environment - primarily of radioiodines and cesium - heavily affecting the northern portions of the country, with settlement-averaged thyroid doses estimated to range from 10 mGy to more than 10 Gy. The increased risk of thyroid cancer among exposed children and adolescents is well established but the impact of radioactive contamination on the risk of other types of cancer is much less certain. To provide data on a public health issue of major importance, we have analyzed the incidence of non-thyroid cancers during the post-Chernobyl period in a well-defined cohort of 13,203 individuals who were cancers identified through linkage with the National Cancer Registry of Ukraine for the period 1998 through 2009. We compared the observed and expected number of cases in three cancer groupings: all solid cancers excluding thyroid, leukemia, and lymphoma. Our analyses found no evidence of a statistically significant elevation in cancer risks in this cohort exposed at radiosensitive ages, although the cancer trends, particularly for leukemia (SIR=1.92, 95% confidence interval: 0.69; 4.13), should continue to be monitored.

  4. The K2-ESPRINT Project V: a short-period giant planet orbiting a subgiant star

    CERN Document Server

    Van Eylen, Vincent; Gandolfi, Davide; Dai, Fei; Winn, Joshua N; Hirano, Teriyuki; Narita, Norio; Bruntt, Hans; Prieto-Arranz, Jorge; Bejar, Victor J S; Nowak, Grzegorz; Lund, Mikkel N; Palle, Enric; Ribas, Ignasi; Sanchis-Ojeda, Roberto; Yu, Liang; Arriagada, Pamela; Butler, R Paul; Crane, Jeffrey D; Handberg, Rasmus; Deeg, Hans; Jessen-Hansen, Jens; Johnson, John A; Nespral, David; Rogers, Leslie; Ryu, Tsuguru; Shectman, Stephen; Shrotriya, Tushar; Slumstrup, Ditte; Takeda, Yoichi; Teske, Johanna; Thompson, Ian; Vanderburg, Andrew; Wittenmyer, Robert

    2016-01-01

    We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood, but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 is an evolved star with a spectroscopically derived stellar radius and mass of $3.88^{+0.48}_{-0.42}~\\mathrm{R_\\odot}$ and $1.53^{+0.13}_{-0.12}~\\mathrm{M_\\odot}$, respectively, and a very close-in transiting planet, with $a/R_\\star = 3.4$. Radial velocity (RV) follow-up using the HARPS, FIES and PFS instruments leads to a planetary mass of $50.3^{+9.7}_{-9.4}~\\mathrm{M_\\oplus}$. In combination with a radius measurement of $8.3 \\pm 1.1~\\mathrm{R_\\oplus}$, this results in a mean planetary density of $0.50^{+0.29}_{-0.17}$ g~cm$^{-3}$...

  5. A New Model of Roche Lobe Overflow for Short-period Gaseous Planets and Binary Stars

    Science.gov (United States)

    Jackson, Brian; Arras, Phil; Penev, Kaloyan; Peacock, Sarah; Marchant, Pablo

    2017-02-01

    Some close-in gaseous exoplanets are nearly in Roche lobe contact, and previous studies show that tidal decay can drive hot Jupiters into contact during the main sequence of their host stars. Improving on a previous model, we present a revised model for mass transfer in a semidetached binary system that incorporates an extended atmosphere around the donor and allows for an arbitrary mass ratio. We apply this new formalism to hypothetical, confirmed, and candidate planetary systems to estimate mass-loss rates and compare with models of evaporative mass loss. Overflow may be significant for hot Neptunes out to periods of ∼2 days, while for hot Jupiters, it may only be important inward of 0.5 days. We find that CoRoT-24 b may be losing mass at a rate of more than an Earth mass in a gigayear. The hot Jupiter WASP-12 b may lose an Earth mass in a megayear, while the putative planet PTFO8-8695 orbiting a T Tauri star might shed its atmosphere in a few megayears. We point out that the orbital expansion that can accompany mass transfer may be less effective than previously considered because the gas accreted by the host star removes some of the angular momentum from the orbit, but simple scaling arguments suggest that the Roche lobe overflow might remain stable. Consequently, the recently discovered small planets in ultrashort periods (model presented here has been incorporated into Modules for Experiments in Stellar Astrophysics (MESA).

  6. The K2-ESPRINT Project V: a short-period giant planet orbiting a subgiant star

    DEFF Research Database (Denmark)

    Van Eylen, Vincent; Albrecht, Simon; Gandolfi, Davide;

    2016-01-01

    {R_\\odot}$ and $1.53^{+0.13}_{-0.12}~\\mathrm{M_\\odot}$, respectively, and a very close-in transiting planet, with $a/R_\\star = 3.4$. Radial velocity (RV) follow-up using the HARPS, FIES and PFS instruments leads to a planetary mass of $50.3^{+9.7}_{-9.4}~\\mathrm{M_\\oplus}$. In combination with a radius measurement......We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly...... understood, but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 is an evolved star with a spectroscopically derived stellar radius and mass of $3.88^{+0.48}_{-0.42}~\\mathrm...

  7. Numerical simulation of short period Earth rotation variations induced by ocean tides

    Science.gov (United States)

    Goss, Andreas; Schindelegger, Michael; Seitz, Florian

    2016-04-01

    The Dynamic Model for Earth Rotation and Gravity (DyMEG) has been used in several previous studies for the numerical simulation of Earth rotation (polar motion and length-of-day) on time scales from seasons to decades. Our current activities aim at the extension of the model and its application for the simulation of high frequency Earth rotation signals with periods of a few hours up to several days. This requires several model adaptations, such as the incorporation of additional excitation mechanisms as well as the identification and implementation of an appropriate numerical integrator. Here we particularly focus on the effect of ocean tides as they - due to their strictly periodic signal characteristics - provide a good possibility to evaluate the performance of the model and to detect potential computational problems. Secondary effects due to atmospheric and non-tidal oceanic influences are incorporated as well. We validate the simulated polar motion and length-of-day time series against hourly GNSS (Global Navigation Satellite System) data and conventional ocean tide routines of the IERS (International Earth Rotation and Reference Systems Service).

  8. Effect of a short period of fluoride ingestion on dental fluorosis in cattle

    Energy Technology Data Exchange (ETDEWEB)

    Suttie, J.W.; Faltin, E.C.

    1971-02-01

    The effects of the ingestion of 2.5 mg of fluoride per kilogram of body weight by dairy heifers during their 13th to 15th or 16th to 18th months of age were studied. This short-term exposure was sufficient to cause severe dental fluorosis in at least one pair of incisors, especially in the 2nd group of heifers, even though the total fluoride intake was not excessive. The plasma fluoride concentrations rapidly increased to 0.5 ppm in both groups of heifers and decreased rapidly after fluoride was removed from the ration. Evidence of dental fluorosis was seen when crown formation was completed before exposure to fluoride and also when the fluoride exposure preceded any calcification of the crown. The most severe effects were seen when the exposure coincided with the initiation of crown formation for a particular incisor. Fluoride analysis of consecutive chronologic sections of the avascular enamel indicated that there was a regular pattern of enamel apposition from the top to the bottom of the crown of one incisor before the top of the crown of the next incisor calcified. 13 references, 3 figures, 3 tables.

  9. Multiculturalism, extreme poverty, and teaching p4c in Juchitán: a short report on research

    OpenAIRE

    Madrid, María Elena; Universidad Pedagógica Nacional

    2009-01-01

    Most of the Latin American population, including in places like Mexico and Brazil, is becoming extremely poor, slipping in the last ten years from poverty to extreme poverty. Native communities are in this condition: to live only to survive, lacking any opportunity to improve or at least meet their basics needs of food and shelter. I practiced P4C in the multicultural community of Juchitán, Oaxaca, to inquire whether the program could overcome the limitations of extreme poverty, and respect c...

  10. Visualization of short-term heart period variability with network tools as a method for quantifying autonomic drive

    CERN Document Server

    Makowiec, Danuta; Kaczkowska, Agnieszka; Graff, Grzegorz; Wejer, Dorota; Wdowczyk, Joanna; Zarczynska-Buchowiecka, Marta; Gruchala, Marcin; Struzik, Zbigniew R

    2014-01-01

    Signals from heart transplant recipients can be considered to be a natural source of information for a better understanding of the impact of the autonomic nervous system on the complexity of heart rate variability. Beat-to-beat heart rate variability can be represented as a network of increments between subsequent $RR$-intervals, which makes possible the visualization of short-term heart period fluctuations. A network is constructed of vertices representing increments between subsequent $RR$-intervals, and edges which connect adjacent $RR$-increments. Two modes of visualization of such a network are proposed. The method described is applied to nocturnal Holter signals recorded from healthy young people and from cardiac transplant recipients. Additionally, the analysis is performed on surrogate data: shuffled RR-intervals (to display short-range dependence), and shuffled phases of the Fourier Transform of RR-intervals (to filter out linear dependences). Important nonlinear properties of autonomic nocturnal reg...

  11. X-ray and EUV Observations of Simultaneous Short and Long Period Oscillations in Hot Coronal Arcade Loops

    CERN Document Server

    Kumar, Pankaj; Cho, Kyung-Suk

    2015-01-01

    We report decaying quasi-periodic intensity oscillations in the X-ray (6-12 keV) and extreme ultraviolet (EUV) channels (131, 94, 1600, 304 \\AA) observed by the Fermi GBM (Gamma-ray Burst Monitor) and SDO/AIA, respectively, during a C-class flare. The estimated period of oscillation and decay time in the X-ray channel (6-12 keV) was about 202 s and 154 s, respectively. A similar oscillation period was detected at the footpoint of the arcade loops in the AIA 1600 and 304 \\AA channels. Simultaneously, AIA hot channels (94 and 131 \\AA) reveal propagating EUV disturbances bouncing back and forth between the footpoints of the arcade loops. The period of the oscillation and decay time were about 409 s and 1121 s, respectively. The characteristic phase speed of the wave is about 560 km/s for about 115 Mm loop length, which is roughly consistent with the sound speed at the temperature about 10-16 MK (480-608 km/s). These EUV oscillations are consistent with the SOHO/SUMER Doppler-shift oscillations interpreted as the...

  12. A Population of planetary systems characterized by short-period, Earth-sized planets

    Science.gov (United States)

    Steffen, Jason H.; Coughlin, Jeffrey L.

    2016-01-01

    We analyze data from the Quarter 1–17 Data Release 24 (Q1–Q17 DR24) planet candidate catalog from NASA’s Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined (≳17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters. PMID:27790984

  13. A Population of planetary systems characterized by short-period, Earth-sized planets.

    Science.gov (United States)

    Steffen, Jason H; Coughlin, Jeffrey L

    2016-10-25

    We analyze data from the Quarter 1-17 Data Release 24 (Q1-Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly 1-d orbital period. We estimate that at least 24 of the 144 systems we examined ([Formula: see text]17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.

  14. A population of planetary systems characterized by short-period, Earth-sized planets

    CERN Document Server

    Steffen, Jason H

    2016-01-01

    We analyze data from the Quarter 1-17 Data Release 24 (Q1--Q17 DR24) planet candidate catalog from NASA's Kepler mission, specifically comparing systems with single transiting planets to systems with multiple transiting planets, and identify a distinct population of exoplanets with a necessarily distinct system architecture. Such an architecture likely indicates a different branch in their evolutionary past relative to the typical Kepler system. The key feature of these planetary systems is an isolated, Earth-sized planet with a roughly one-day orbital period. We estimate that at least 24 of the 144 systems we examined (>~17%) are members of this population. Accounting for detection efficiency, such planetary systems occur with a frequency similar to the hot Jupiters.

  15. Tailoring of the electrical and thermal properties using ultra-short period non-symmetric superlattices

    Science.gov (United States)

    Komar, Paulina; Chávez-Ángel, Emigdio; Euler, Christoph; Balke, Benjamin; Kolb, Ute; Müller, Mathis M.; Kleebe, Hans-Joachim; Fecher, Gerhard H.; Jakob, Gerhard

    2016-10-01

    Thermoelectric modules based on half-Heusler compounds offer a cheap and clean way to create eco-friendly electrical energy from waste heat. Here we study the impact of the period composition on the electrical and thermal properties in non-symmetric superlattices, where the ratio of components varies according to (TiNiSn)n:(HfNiSn)6-n, and 0 ⩽ n ⩽ 6 unit cells. The thermal conductivity (κ) showed a strong dependence on the material content achieving a minimum value for n = 3, whereas the highest value of the figure of merit ZT was achieved for n = 4. The measured κ can be well modeled using non-symmetric strain relaxation applied to the model of the series of thermal resistances.

  16. Merging binary black holes formed through chemically homogeneous evolution in short-period stellar binaries

    Science.gov (United States)

    Mandel, Ilya; de Mink, Selma E.

    2016-05-01

    We explore a newly proposed channel to create binary black holes of stellar origin. This scenario applies to massive, tight binaries where mixing induced by rotation and tides transports the products of hydrogen burning throughout the stellar envelopes. This slowly enriches the entire star with helium, preventing the build-up of an internal chemical gradient. The stars remain compact as they evolve nearly chemically homogeneously, eventually forming two black holes, which we estimate typically merge 4-11 Gyr after formation. Like other proposed channels, this evolutionary pathway suffers from significant theoretical uncertainties, but could be constrained in the near future by data from advanced ground-based gravitational-wave detectors. We perform Monte Carlo simulations of the expected merger rate over cosmic time to explore the implications and uncertainties. Our default model for this channel yields a local binary black hole merger rate of about 10 Gpc-3 yr-1 at redshift z = 0, peaking at twice this rate at z = 0.5. This means that this channel is competitive, in terms of expected rates, with the conventional formation scenarios that involve a common-envelope phase during isolated binary evolution or dynamical interaction in a dense cluster. The events from this channel may be distinguished by the preference for nearly equal-mass components and high masses, with typical total masses between 50 and 110 M⊙. Unlike the conventional isolated binary evolution scenario that involves shrinkage of the orbit during a common-envelope phase, short time delays are unlikely for this channel, implying that we do not expect mergers at high redshift.

  17. X-RAY AND EUV OBSERVATIONS OF SIMULTANEOUS SHORT AND LONG PERIOD OSCILLATIONS IN HOT CORONAL ARCADE LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pankaj; Cho, Kyung-Suk [Korea Astronomy and Space Science Institute (KASI), Daejeon, 305-348 (Korea, Republic of); Nakariakov, Valery M., E-mail: pankaj@kasi.re.kr [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, CV4 7AL (United Kingdom)

    2015-05-01

    We report decaying quasi-periodic intensity oscillations in the X-ray (6–12 keV) and extreme-ultraviolet (EUV) channels (131, 94, 1600, 304 Å) observed by the Fermi Gamma-ray Burst Monitor and Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), respectively, during a C-class flare. The estimated periods of oscillation and decay time in the X-ray channel (6–12 keV) were about 202 and 154 s, respectively. A similar oscillation period was detected at the footpoint of the arcade loops in the AIA 1600 and 304 Å channels. Simultaneously, AIA hot channels (94 and 131 Å) reveal propagating EUV disturbances bouncing back and forth between the footpoints of the arcade loops. The period of the oscillation and decay time were about 409 and 1121 s, respectively. The characteristic phase speed of the wave is about 560 km s{sup −1} for about 115 Mm of loop length, which is roughly consistent with the sound speed at the temperature about 10–16 MK (480–608 km s{sup −1}). These EUV oscillations are consistent with the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation Doppler-shift oscillations interpreted as the global standing slow magnetoacoustic wave excited by a flare. The flare occurred at one of the footpoints of the arcade loops, where the magnetic topology was a 3D fan-spine with a null-point. Repetitive reconnection at this footpoint could have caused the periodic acceleration of non-thermal electrons that propagated to the opposite footpoint along the arcade and that are precipitating there, causing the observed 202 s periodicity. Other possible interpretations, e.g., the second harmonics of the slow mode, are also discussed.

  18. Seismic Coupling of Short-Period Wind Noise Through Mars' Regolith for NASA's InSight Lander

    Science.gov (United States)

    Teanby, N. A.; Stevanović, J.; Wookey, J.; Murdoch, N.; Hurley, J.; Myhill, R.; Bowles, N. E.; Calcutt, S. B.; Pike, W. T.

    2016-11-01

    NASA's InSight lander will deploy a tripod-mounted seismometer package onto the surface of Mars in late 2018. Mars is expected to have lower seismic activity than the Earth, so minimisation of environmental seismic noise will be critical for maximising observations of seismicity and scientific return from the mission. Therefore, the seismometers will be protected by a Wind and Thermal Shield (WTS), also mounted on a tripod. Nevertheless, wind impinging on the WTS will cause vibration noise, which will be transmitted to the seismometers through the regolith (soil). Here we use a 1:1-scale model of the seismometer and WTS, combined with field testing at two analogue sites in Iceland, to determine the transfer coefficient between the two tripods and quantify the proportion of WTS vibration noise transmitted through the regolith to the seismometers. The analogue sites had median grain sizes in the range 0.3-1.0 mm, surface densities of 1.3-1.8 g cm^{-3}, and an effective regolith Young's modulus of 2.5^{+1.9}_{-1.4} MPa. At a seismic frequency of 5 Hz the measured transfer coefficients had values of 0.02-0.04 for the vertical component and 0.01-0.02 for the horizontal component. These values are 3-6 times lower than predicted by elastic theory and imply that at short periods the regolith displays significant anelastic behaviour. This will result in reduced short-period wind noise and increased signal-to-noise. We predict the noise induced by turbulent aerodynamic lift on the WTS at 5 Hz to be ˜2×10^{-10} ms^{-2} Hz^{-1/2} with a factor of 10 uncertainty. This is at least an order of magnitude lower than the InSight short-period seismometer noise floor of 10^{-8} ms^{-2} Hz^{-1/2}.

  19. CSI 2264: Characterizing Young Stars in NGC 2264 with Short-Duration, Periodic Flux Dips in their Light Curves

    CERN Document Server

    Stauffer, John; McGinnis, Pauline; Rebull, Luisa; Hillenbrand, Lynne A; Turner, Neal J; Carpenter, John; Plavchan, Peter; Carey, Sean; Terebey, Susan; Morales-Calderón, María; Alencar, Silvia H P; Bouvier, Jerome; Venuti, Laura; Hartmann, Lee; Calvet, Nuria; Micela, Giusi; Flaccomio, Ettore; Song, Inseok; Gutermuth, Rob; Barrado, David; Vrba, Frederick J; Covey, Kevin; Padgett, Debbie; Herbst, William; Gillen, Edward; Lyra, Wladimir; Guimaraes, Marcelo Medeiros; Bouy, Herve; Favata, Fabio

    2015-01-01

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical {\\em CoRoT} light curves exhibiting short-duration, shallow, periodic flux dips. All of these stars have infrared (IR) excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHM generally less than one day, depths almost always less than 15%, and periods (3period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected on successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard "disk-locking" models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In so...

  20. Ultra Short Period Planets in K2: SuPerPiG Results for Campaigns 0-5

    CERN Document Server

    Adams, Elisabeth R; Endl, Michael

    2016-01-01

    We analyzed data from Campaigns 0-5 of the K2 mission and report 19 ultra-short period candidate planets with orbital periods of less than 1 day (nine of which have not been previously reported). The planet candidates range from 0.7-16 Earth radii and periods of 4.2-23.5 hours. One candidate (EPIC 203533312, Kp=12.5) is among the shortest-period planet candidates discovered to date, and, if confirmed as a planet, must have a density of at least rho=8.9 g/cm^3 in order to not be tidally disrupted. Four candidates have nominal radius values in the sub-Jovian desert (3-11 R_E, period under 1.5 days) where theoretical models do not favor their long-term stability; the only confirmed planet in this range is in fact thought to be disintegrating (EPIC 201637175). In addition to the planet candidates, we report on EPIC 211152484, which has intermittent transits that are only visible during about half of the observing campaign, and whose true nature is unclear. Based on an assessment of our survey's completeness, we e...

  1. BVRI Photometric Study of the Short Period, Solar Type, Semi-Detached Binary, NSVS 10083189

    Science.gov (United States)

    Samec, Ronald G.; Caton, Daniel B.; Olsen, Amber; Faulkner, Danny R.; Hill, Robert L.

    2017-06-01

    Precision BVRcIc light curves of NSVS 5066754 were taken on 11 nights in February through April 2015 at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University and on 1 night on the SARA 1-m reflector at Kitt Peak National Observatory in remote mode. It is an ~ F8V eclipsing binary with a period of 0.4542238 (2) d.Seven times of minimum light were calculated, for 5 primary and 2 secondary eclipses from our present observations:HJD I = 2457067.75453±0.0003, 2457088.64907±0.0001, 2457089.55708±0.0001, 2457098.64163±0.0004, 24557113.63117±0.0002HJD II = 2457066.61874±0.0008, 2457067.52329±0.0017.In addition, seven observations at minima were introduced as low weighted times of minimum light taken from archived NSVS Data.The following decreasing quadratic ephemeris was determined from all available times of minimum light in this study covering some 15 years:JD Hel MinI = 2457089.55665±0.00054d + 0.4542179±0. 0000006 X E -0.00000000049±0.00000000005 × E2We note that this result has a strong level of confidence. This again gives evidence that the components are coming into contact possibly due to magnetic braking as indicated by dark spot activity on the binary.We initially modeled the B,V,R,I curves simultaneously with the Wilson-Devinney program in a shallow contact configuration (mode 3) as indicated by our Binary Maker 3 fits. This led to a near but non-contact configuration. Next, the general Mode 2 was used to give clues regarding the configuration. During this investigation, the primary component came into contact while the secondary star remained detached. Next, a solution was determined in a semidetached, mode 4 state (larger component filling its critical lobe and the secondary under filing. This may indicate that NSVS 10083189 is coming into contact for the first time. The mode and the period change corroborate.Our semi-detached, near contact solution, gave a mass ratio of 0.58, with component temperatures of

  2. POSSIBLE DISINTEGRATING SHORT-PERIOD SUPER-MERCURY ORBITING KIC 12557548

    Energy Technology Data Exchange (ETDEWEB)

    Rappaport, S.; El Mellah, I.; Kotson, M.; Tran, K. [37-602B, M.I.T. Department of Physics and Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Levine, A.; Kalomeni, B. [37-575, M.I.T. Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge, MA 02139 (United States); Chiang, E. [Department of Astronomy, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411 (United States); Jenkins, J. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Kite, E. S. [Department of Earth and Planetary Science, UC Berkeley, 307 McCone Hall, Berkeley, CA 94720-4767 (United States); Nelson, L. [Department of Physics, Bishop' s University, 2600 College St., Sherbrooke, Quebec, QC J1M 1Z7 (Canada); Rousseau-Nepton, L., E-mail: sar@mit.edu, E-mail: aml@space.mit.edu, E-mail: echiang@astro.berkeley.edu, E-mail: ielmelah@ens-cachan.fr, E-mail: Jon.M.Jenkins@nasa.gov, E-mail: belinda.kalomeni@ege.edu.tr, E-mail: ekite@caltech.edu, E-mail: lnelson@ubishops.ca, E-mail: laurie.r-nepton.1@ulaval.ca [Departement de physique, de genie physique et d' optique, Universite Laval, Quebec, QC G1K 7P4 (Canada)

    2012-06-10

    We report on the discovery of stellar occultations, observed with Kepler, which recur periodically at 15.685 hr intervals, but which vary in depth from a maximum of 1.3% to a minimum that can be less than 0.2%. The star that is apparently being occulted is KIC 12557548, a V = 16 mag K dwarf with T{sub eff,s} {approx_equal} 4400 K. The out-of-occultation behavior shows no evidence for ellipsoidal light variations, indicating that the mass of the orbiting object is less than {approx}3 M{sub J} (for an orbital period of 15.7 hr). Because the eclipse depths are highly variable, they cannot be due solely to transits of a single planet with a fixed size. We discuss but dismiss a scenario involving a binary giant planet whose mutual orbit plane precesses, bringing one of the planets into and out of a grazing transit. This scenario seems ruled out by the dynamical instability that would result from such a configuration. We also briefly consider an eclipsing binary, possibly containing an accretion disk, that either orbits KIC 12557548 in a hierarchical triple configuration or is nearby on the sky, but we find such a scenario inadequate to reproduce the observations. The much more likely explanation-but one which still requires more quantitative development-involves macroscopic particles escaping the atmosphere of a slowly disintegrating planet not much larger than Mercury in size. The particles could take the form of micron-sized pyroxene or aluminum oxide dust grains. The planetary surface is hot enough to sublimate and create a high-Z atmosphere; this atmosphere may be loaded with dust via cloud condensation or explosive volcanism. Atmospheric gas escapes the planet via a Parker-type thermal wind, dragging dust grains with it. We infer a mass-loss rate from the observations of order 1 M{sub Circled-Plus} Gyr{sup -1}, with a dust-to-gas ratio possibly of order unity. For our fiducial 0.1 M{sub Circled-Plus} planet (twice the mass of Mercury), the evaporation timescale may

  3. Results of Short-Period Helicopter System Identification Using Output-Error and Hybrid Search-Gradient Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Ronaldo Vieira Cruz

    2010-01-01

    Full Text Available This article focuses on the problem of parameter estimation of the uncoupled, linear, short-period aerodynamic derivatives of a “Twin Squirrel” helicopter in level flight and constant speed. A flight test campaign is described with respect to maneuver specification, flight test instrumentation, and experimental data collection used to estimate the aerodynamic derivatives. The identification problem is solved in the time domain using the output-error approach, with a combination of Genetic Algorithm (GA and Levenberg-Marquardt optimization algorithms. The advantages of this hybrid GA and gradient-search methodology in helicopter system identification are discussed.

  4. Influence of temperature of the short-period heat treatment on mechanical properties of the NiTi alloy

    Directory of Open Access Journals (Sweden)

    Jaroslav Čapek

    2014-01-01

    Full Text Available The equiatomic alloy of nickel and titanium, known as nitinol, possesses unique properties such as superelasticity, pseudoplasticity, shape memory, while maintaining good corrosion resistance and sufficient biocompatibility. Therefore it is used for production of various devices including surgery implants. Heat treatment of nickel-rich NiTi alloys can result in precipitation of nickel-rich phases, which strongly influence tensile and fatigue behaviour of the material.In this work we have studied influence of short-period heat treatment on tensile behaviour and fatigue life of the NiTi (50.9 at. % Ni wire intended for fabrication of surgery stents.

  5. A population of planetary systems from Kepler data that are characterized by short-period, Earth-sized planets

    Science.gov (United States)

    Steffen, Jason H.; Coughlin, Jeffrey

    2017-01-01

    From an analysis of the Quarter 1-17 Kepler planet candidate catalog we compare systems with single transiting planets to systems with multiple transiting planets. We find a distinct population of exoplanetary systems that is characterized by short-period, Earth sized planets. This difference in system architecture likely indicates a different branch in the system's formation or dynamical evolution relative to the typical Kepler system. We estimate that at least 17% of systems containing a hot Earth planet are members of this population. When we account for detection efficiency, these systems occur with a frequency similar to the hot Jupiters.

  6. Multidisciplinary experiment on studying short-period variability of the sedimentary process in the northeastern part of the Black Sea

    Science.gov (United States)

    Klyuvitkin, A. A.; Ostrovskii, A. G.; Novigatskii, A. N.; Lisitzin, A. P.

    2016-07-01

    The principal aim of this work is to reveal the regularities of short-period synoptic variability of vertical flows and the composition of settling sedimentary material, to obtain information on the quantitative characteristics of the processes that influence sound-scattering layers in the water layer above the continental slope behind the shelf edge in the northeastern part of the Black Sea. The results were obtained due to improvement of the equipment and the procedures for performing sea experiments on studying physicogeological, biological, and hydrophysical processes in the upper illuminated layer of phytoplankton development.

  7. Short period forecasting of catchment-scale precipitation. Part I: the role of Numerical Weather Prediction

    Directory of Open Access Journals (Sweden)

    M. A. Pedder

    2000-01-01

    Full Text Available A deterministic forecast of surface precipitation involves solving a time-dependent moisture balance equation satisfying conservation of total water substance. A realistic solution needs to take into account feedback between atmospheric dynamics and the diabatic sources of heat energy associated with phase changes, as well as complex microphysical processes controlling the conversion between cloud water (or ice and precipitation. Such processes are taken into account either explicitly or via physical parameterisation schemes in many operational numerical weather prediction models; these can therefore generate precipitation forecasts which are fully consistent with the predicted evolution of the atmospheric state as measured by observations of temperature, wind, pressure and humidity. This paper reviews briefly the atmospheric moisture balance equation and how it may be solved in practice. Solutions are obtained using the Meteorological Office Mesoscale version of its operational Unified Numerical Weather Prediction (NWP model; they verify predicted precipitation rates against catchment-scale values based on observations collected during an Intensive Observation Period (IOP of HYREX. Results highlight some limitations of an operational NWP forecast in providing adequate time and space resolution, and its sensitivity to initial conditions. The large-scale model forecast can, nevertheless, provide important information about the moist dynamical environment which could be incorporated usefully into a higher resolution, ‘storm-resolving’ prediction scheme. Keywords: Precipitation forecasting; moisture budget; numerical weather prediction

  8. Possible Disintegrating Short-Period Super-Mercury Orbiting KIC 12557548

    CERN Document Server

    Rappaport, S; Chiang, E; Mellah, I El; Jenkins, J; Kalomeni, B; Kotson, M; Nelson, L; Rousseau-Nepton, L; Tran, K

    2012-01-01

    We report here on the discovery of stellar occultations, observed with Kepler, that recur periodically at 15.685 hour intervals, but which vary in depth from a maximum of 1.2% to a minimum that can be less than 0.2%. The star that is apparently being occulted is KIC 12557548, a V = 16 magnitude K dwarf with T_eff = 4400 K. The out-of-occultation behavior shows no evidence for ellipsoidal light variations, indicating that the mass of the orbiting object is less than ~3 M_J. Because the eclipse depths are highly variable, they cannot be due solely to transits of a single planet with a fixed size. We discuss but dismiss a scenario involving a binary giant planet whose mutual orbit plane precesses, bringing one of the planets into and out of a grazing transit. This scenario seems ruled out by the dynamical instability that would result from such a configuration. The much more likely explanation involves macroscopic particles - e.g., dust, possibly in the form of micron-sized pyroxene grains - escaping the atmosph...

  9. Probability Estimates of Solar Proton Doses During Periods of Low Sunspot Number for Short Duration Missions

    Science.gov (United States)

    Atwell, William; Tylka, Allan J.; Dietrich, William F.; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper presented at ICES in 2015, we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the monthly smoothed sunspot number (SSN) was less than 30. Although such months are generally considered "solar-quiet", SPEs observed during these months even include Ground Level Events, the most energetic type of SPE. In this paper, we add to previous study those SPEs that occurred in 1973-2015 when the SSN was greater than 30 but less than 50. Based on the observable energy range of the solar protons, we classify the event as GLEs, sub-GLEs, and sub-sub-GLEs, all of which are potential contributors to the radiation hazard. We use the spectra of these events to construct a probabilistic model of the absorbed dose due to solar protons when SSN < 50 at various confidence levels for various depths of shielding and for various mission durations. We provide plots and tables of solar proton-induced absorbed dose as functions of confidence level, shielding thickness, and mission-duration that will be useful to system designers.

  10. On the use of volumetric strain meters to infer additional characteristics of short-period seismic radiation

    Science.gov (United States)

    Borcherdt, R.D.; Johnston, M.J.S.; Glassmoyer, G.

    1989-01-01

    Volumetric strain meters (Sacks-Evertson design) are installed at 15 sites along the San Andreas fault system, to monitor long-term strain changes for earthquake prediction. Deployment of portable broadband, high-resolution digital recorders (GEOS) at several of the sites extends the detection band for volumetric strain to periods shorter than 5 ?? 10-2 sec and permits the simultaneous observation of seismic radiation fields using conventional short-period pendulum seismometers. Recordings of local and regional earthquakes indicate that dilatometers respond to P energy but not direct shear energy and that straingrams can be used to resolve superimposed reflect P and S waves for inference of wave characteristics not permitted by either sensor alone. Simultaneous measurements of incident P- and S-wave amplitudes are used to introduce a technique for single-station estimates of wave field inhomogeneity, free-surface reflection coefficients and local material P velocity. -from Authors

  11. Short-period intrinsic Stark GaN /AlGaN superlattice as a Bloch oscillator

    Science.gov (United States)

    Litvinov, V. I.; Manasson, A.; Pavlidis, D.

    2004-07-01

    We discuss the properties of AlGaN /GaN superlattice (SL) related to the feasibility of a terahertz-range oscillator. The distortion of the conduction-band profile by the polarization fields has been taken into account. We have calculated the conduction-band offset between the pseudomorphic AlGaN barrier and the GaN quantum well, the first miniband width and energy dispersion, as functions of Al content in the barrier. As the short-period SL miniband energy dispersion contains contributions from next to nearest neighbors, it causes anharmonic electron oscillations at the multiples of the fundamental Bloch frequency. The Al content and SL period that favor high-frequency oscillations have been determined.

  12. Early Oligocene geomagnetic field behavior from ODP Site 1128: Complex records of short-period polarity events

    Science.gov (United States)

    Molina-Garza, R. S.; Fuller, M. D.

    2001-12-01

    At Site 1128, in the Great Australian Bight, Leg 182 of the Ocean Drilling Program recovered a thick (~350 m) section of Upper Eocene and Lower Oligocene marine calcareous clays. Shipboard measurements established a magnetostratigraphy that can unambiguously be correlated to chrons C13n to C10n of the global polarity time scale (GPTS), and a less complete record of chrons C17n to C15r (due to poor core recovery). Correlation to the GPTS is further supported by available biostratigraphic data. For the Lower Oligocene sequence, average sedimentation rate is estimated at ~4 cm/kyr. The sediments recovered thus allow to test for the completeness and reliability of the geomagnetic field polarity during the Early Oligocene. The original shipboard long-core measurements suggested the presence of additional short polarity events or geomagnetic field excursions during chrons C13n, C12r, C11r, and C11n. In order to examine the reliability of the record and the nature of possible short-polarity events, we obtained discrete samples from the entire sequence at ~1 m intervals, with a closer sample spacing in critical intervals (~10 cm). The natural remanence of these sediments is normally simple. After removing a small soft overprint, the magnetization decays towards the origin with distributed coercivities and distributed unblocking temperatures. Demagnetization behavior and other rock magnetic data indicate that the remanence resides primarily in a cubic phase such as magnetite or maghemite, with a small contribution from hematite. Discrete samples from chron C12r did not reproduce the long-core record for two of the supposed events, single samples suggest the presence of short events or cryptochrons near the base of both C13n and C12r, and multiple samples suggest the existence of short-period normal polarity events during C11r and near the top of C12r. The records of these events are, however, complex. Demagnetization results indicate that the magnetization consists of an

  13. Short-period volcanic gas precursors to phreatic eruptions: Insights from Poás Volcano, Costa Rica

    Science.gov (United States)

    de Moor, Maarten; Aiuppa, Alessandro; Pacheco, Javier; Avard, Geoffroy; Kern, Christoph; Liuzzo, Marco; Martinez, Maria; Giudice, Gaetano; Fischer, Tobias P.

    2016-01-01

    Volcanic eruptions involving interaction with water are amongst the most violent and unpredictable geologic phenomena on Earth. Phreatic eruptions are exceptionally difficult to forecast by traditional geophysical techniques. Here we report on short-term precursory variations in gas emissions related to phreatic blasts at Poás volcano, Costa Rica, as measured with an in situ multiple gas analyzer that was deployed at the edge of the erupting lake. Gas emitted from this hyper-acid crater lake approaches magmatic values of SO2/CO2 1–6 days prior to eruption. The SO2 flux derived from magmatic degassing through the lake is measureable by differential optical absorption spectrometry (sporadic campaign measurements), which allows us to constrain lake gas output and input for the major gas species during eruptive and non-eruptive periods. We can further calculate power supply to the hydrothermal system using volatile mass balance and thermodynamics, which indicates that the magmatic heat flux into the shallow hydrothermal system increases from ∼27 MW during quiescence to ∼59 MW during periods of phreatic events. These transient pulses of gas and heat from the deeper magmatic system generate both phreatic eruptions and the observed short-term changes in gas composition, because at high gas flux scrubbing of sulfur by the hydrothermal system is both kinetically and thermodynamically inhibited whereas CO2gas is always essentially inert in hyperacid conditions. Thus, the SO2/CO2 of lake emissions approaches magmatic values as gas and power supply to the sub-limnic hydrothermal system increase, vaporizing fluids and priming the hydrothermal system for eruption. Our results suggest that high-frequency real-time gas monitoring could provide useful short-term eruptive precursors at volcanoes prone to phreatic explosions.

  14. 2-D Physical Modeling to Measure the Effectiveness of Perforated Skirt Breakwater for Short-Period Waves

    Directory of Open Access Journals (Sweden)

    Harman Ajiwibowo

    2011-04-01

    Full Text Available The effectiveness of a breakwater can be measured by quantifying the transmission coefficient (KT. The smaller the coefficient, the better the performance of the breakwater. A physical modeling on the proposed breakwater was conducted to identify the coefficient of Perforated Skirt Breakwater (PSB. The PSB model was tested in 2-D wave flume at Ocean Wave Research Laboratory FTSL ITB, to obtain the effectiveness of PSB for short-period waves (prototype periods, Tp= 4 second and smaller. The scaling of PSB models applies the principle of Froude Similarity, where the Froude number in model equals to the Froude number in prototype (Frm=Frp. The flume is equipped with 5 resistance-type wave probes and 8-channel DAS (Data Acquisition System. Wave heights (H and wave periods (T data were observed both manually by visual observation and wave probes readings (processed later with method of “zero mean up-crossing” technique. The incoming wave heights (Hi and transmitted wave heights (Ht were measured and processed to obtain the transmission coefficient (KT. The relationships between KT and non-dimensional variables (skirt draft / incident wave height, S/Hi are analyzed and the calculated effectiveness of the PSB for varied environmental condition is obtained to be up to 70%.Abstract. The effectiveness of a breakwater can be measured by quantifying the transmission coefficient (KT. The smaller the coefficient, the better the performance of the breakwater. A physical modeling on the proposed breakwater was conducted to identify the coefficient of Perforated Skirt Breakwater (PSB. The PSB model was tested in 2-D wave flume at Ocean Wave Research Laboratory FTSL ITB, to obtain the effectiveness of PSB for short-period waves (prototype periods, Tp= 4 second and smaller. The scaling of PSB models applies the principle of Froude Similarity, where the Froude number in model equals to the Froude number in prototype (Frm=Frp. The flume is equipped with 5

  15. Duty periods with early start times restrict the amount of sleep obtained by short-haul airline pilots.

    Science.gov (United States)

    Roach, Gregory D; Sargent, Charli; Darwent, David; Dawson, Drew

    2012-03-01

    Most of the research related to human fatigue in the aviation industry has focussed on long-haul pilots, but short-haul pilots also experience elevated levels of fatigue. The aim of this study was to examine the impact of early start times on the amount of sleep obtained prior to duty and on fatigue levels at the start of duty. Seventy short-haul pilots collected data regarding their duty schedule and sleep/wake behaviour for at least two weeks. Data were collected using self-report duty/sleep diaries and wrist activity monitors. Mixed-effects regression analyses were used to examine the effects of duty start time (04:00-10:00 h) on (i) the total amount of sleep obtained in the 12h prior to the start of duty and (ii) self-rated fatigue level at the start of duty. Both analyses indicated significant main effects of duty start time. In particular, the amount of sleep obtained in the 12h prior to duty was lowest for duty periods that commenced between 04:00 and 05:00 h (i.e. 5.4h), and greatest for duty periods that commenced between 09:00 and 10:00 h (i.e. 6.6h). These data indicate that approximately 15 min of sleep is lost for every hour that the start of duty is advanced prior to 09:00 h. In addition, self-rated fatigue at the start of duty was highest for duty periods that commenced between 04:00 and 05:00 h, and lowest for duty periods that commenced between 09:00 and 10:00 h. Airlines should implement a fatigue risk management system (FRMS) for short-haul pilots required to work early-morning shifts. One component of the FRMS should be focussed on the production of 'fatigue-friendly' rosters. A second component of the FRMS should be focussed on training pilots to optimise sleep opportunities, to identify circumstances where the likelihood of fatigue is elevated, and to manage the risks associated with fatigue-related impairment.

  16. CSI 2264: CHARACTERIZING YOUNG STARS IN NGC 2264 WITH SHORT-DURATION PERIODIC FLUX DIPS IN THEIR LIGHT CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); McGinnis, Pauline; Alencar, Silvia H. P. [Departamento de Física—ICEx—UFMG, Av. Antônio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Hillenbrand, Lynne A.; Carpenter, John [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Terebey, Susan [Department of Physics and Astronomy, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Morales-Calderón, María [Centro de Astrobiología, Dpto. de Astrofísica, INTA-CSIC, PO BOX 78, E-28691, ESAC Campus, Villanueva de la Cañada, Madrid (Spain); Bouvier, Jerome; Venuti, Laura [Université de Grenoble, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), F-38000 Grenoble (France); CNRS, IPAG, F-38000 Grenoble (France); Hartmann, Lee; Calvet, Nuria [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); Micela, Giusi; Flaccomio, Ettore [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134, Palermo (Italy); Song, Inseok [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602–2451 (United States); Gutermuth, Rob, E-mail: stauffer@ipac.caltech.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); and others

    2015-04-15

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall.

  17. Photometric Studies of Three Neglected Short-period Contact Binaries GN Bootis, BL Leonis, and V1918 Cygni

    Science.gov (United States)

    Yang, Y.-G.; Qian, S.-B.; Dai, H.-F.

    2013-03-01

    We present new photometry for three short-period contact binaries, GN Boo, BL Leo, and V1918 Cyg, observed from 2008 December to 2012 April using several small telescopes in China. Photometric models were deduced from new observations using the updated Wilson-Devinney Code. The results show that GN Boo and BL Leo are W-type contact binaries, while V1918 Cyg is an A-type one. The mass ratios and fill-out factors are q = 0.320(± 0.002) and f = 5.8(± 0.1)% for GN Boo, q = 0.476(± 0.005) and f = 21.3(± 1.1)% for BL Leo, q = 0.264(± 0.002), and f = 49.7(± 0.7)% for V1918 Cyg, respectively. From the (O - C) curves, it is discovered that the orbital periods of three binaries have varied in a complicated way, i.e., cyclic oscillation for GN Boo, long-term period decrease for BL Leo, and both for V1918 Cyg. The cyclic variations for GN Boo and V1918 Cyg may probably be attributed to the magnetic activity of the primary component or light-time effect due to the third body. Meanwhile, the secular period decreases for BL Leo and V1918 Cyg may result from mass transfer from the primary to the secondary, accompanying the mass and angular momentum loss from the central system. Finally, GN Boo, BL Leo, and V1918 Cyg will evolve into deep contact binaries. Additionally, a statistical study of 37 contact binaries with decreasing periods is given. We obtained the relations of q - f and q - dln P/dt, and preliminarily determined the mass loss rate of dln M/dt from the binary system.

  18. CSI 2264: Characterizing Young Stars in NGC 2264 With Short-Duration Periodic Flux Dips in Their Light Curves

    Science.gov (United States)

    Stauffer, John; Cody, Ann Marie; McGinnis, Pauline; Rebull, Luisa; Hillenbrand, Lynne A.; Turner, Neal J.; Carpenter, John; Plavchan, Peter; Carey, Sean; Terebey, Susan; Morales-Calderon, Maria; Alencar, Silvia H. P.; Bouvier, Jerome; Venuti, Laura; Hartmann, Lee; Calvet, Nuria; Micela, Giusi; Flaccomio, Ettore; Song, Inseok; Gutermuth, Rob; Barrado, David; Vrba, Frederick J.; Covey, Kevin; Padgett, Debbie; Herbst, William; Gillen, Edward; Lyra, Wladimir; Guimaraes, Marcelo Medeiros; Bouy, Herve; Favata, Fabio

    2015-01-01

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow, periodic flux dips. All of these stars have infrared (IR) excesses that are consistent with their having inner disk walls near the Keplerian corotation radius. The repeating photometric dips have FWHM generally less than one day, depths almost always less than 15%, and periods (3 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected on successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard \\disk-locking" models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSO in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel- ow accretion columns arising near the inner disk wall.

  19. The New RS CVn Binary V1034 Her Revisited and the orbital period - Activity relation of Short-period RS CVn binaries using photometric distortion amplitude

    CERN Document Server

    liyun, Zhang

    2011-01-01

    This paper presents new CCD BVRI light curves of the newly discovered RS CVn eclipsing binary V1034 Her in 2009 and 2010, which shapes are different from the previous published results. They show asymmetric outside eclipse and we try to use a spot model to explain the phenomena. Using the Wilson-Devinney program with one-spot or two-spots model, photometric solutions of the system and starspot parameters were derived. Comparing the two results, it shows that the case of two spots is better successful in reproducing the light-curve distortions. For all the spot longitudes, it suggests that the trend towards active longitude belts and each active longitude belts might be switch. Comparing the light curves of 2009 and 2010, it indicates that the light curve changes on a long time scale of one year, especially in phase 0.25. In addition, we also collected the values of the maximum amplitudes of photometric distortion of the short-period RS CVn binary. We found for the first time that there is a trend of increasin...

  20. Effect of different feeding levels during three short periods of gestation on sow and litter performance over two reproductive cycles.

    Science.gov (United States)

    Ren, P; Yang, X J; Kim, J S; Menon, D; Baidoo, S K

    2017-02-01

    The present study investigated the effects of different feeding levels during 3 short periods of gestation on sow and litter performance and its impact on subsequent reproductive performance. A total of 160 multiparous sows were allotted to 1 of 4 dietary treatments using a randomized complete block design with initial body weight (BW) and backfat (BF) as the blocking criteria. All sows were fed one common corn-soybean meal-based diet with the amount of 1.0×maintenance energy intake (100×BW(0.75)kcalME/d) throughout gestation except 3 periods of 7 d when dietary treatments were imposed on d 27, d 55 and d 83 of gestation. During the 3 short periods, sows were fed 1 of 4 different feeding levels: 0.5, 1.0, 1.5 and 2.0×maintenance energy level (0.5M, 1.0M, 1.5M and 2.0M, respectively). Results showed that both BW gain (16.12, 24.74, 30.62 and 36.71kg, respectively) and BF change (-0.27, 0.99, 1.49 and 2.45mm, respectively) from d 27 to 109 of gestation increased linearly (Pfeeding levels. In contrast, with the rise of gestation feeding levels, lactation BW gain (14.31, 9.84, 7.09 and 3.50kg, respectively) decreased linearly (Pfeed intake during lactation (7.05, 7.00, 6.91 and 6.52kg, respectively) tended to decrease linearly (P=0.09) in response to the increase of gestation feeding levels. Furthermore, piglet birth weights increased linearly (Pfeeding levels, while piglet weaning weights were similar (P>0.10) among treatments. Subsequent reproductive performance was not affected (P>0.10) by feeding levels during the previous reproductive cycle. In conclusion, increasing feeding levels during 3 short periods of gestation increased BW and BF gains during gestation and caused less BW gain and more BF loss during lactation due to the reduction of lactation feed intake in response to increasing gestation feeding levels. Increasing feeding levels during 3 short periods of gestation increased piglet birth weight, but did not affect piglet weaning weight. The feeding

  1. A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics.

    Science.gov (United States)

    Christensen, Peter M; Jacobs, Robert A; Bonne, Thomas; Flück, Daniela; Bangsbo, Jens; Lundby, Carsten

    2016-06-01

    The aim of the present study was to examine whether improvements in pulmonary oxygen uptake (V̇o2) kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age 26 ± 2 yr; mean ± SD) performed six HIT sessions (8-12 × 60 s at incremental test peak power; 271 ± 52 W) over a 2-wk period. Before and after the HIT period, V̇o2 kinetics was modeled during moderate-intensity cycling (110 ± 19 W). Mitochondrial function was assessed with high-resolution respirometry (HRR), and maximal activities of oxidative enzymes citrate synthase (CS) and cytochrome c oxidase (COX) were accordingly determined. In response to HIT, V̇o2 kinetics became faster (τ: 20.4 ± 4.4 vs. 28.9 ± 6.1 s; P CIIP) (P < 0.05). Collectively, these findings support that selected measures of mitochondrial function obtained with HRR are important for fast V̇o2 kinetics and better markers than maximal oxidative enzyme activity in describing the speed of the V̇o2 response during moderate-intensity exercise.

  2. Effect of streamwise spacing on periodic and random unsteadiness in a bundle of short cylinders confined in a channel

    Science.gov (United States)

    Ostanek, Jason K.; Thole, Karen A.

    2012-12-01

    While flow across long tube bundles is considered classical data, pin-fin arrays made up of short tubes have become a growing topic of interest for use in cooling gas turbine airfoils. Data from the literature indicate that decreasing streamwise spacing increases heat transfer in pin-fin arrays; however, the specific mechanism that causes increased heat transfer coefficients remains unknown. The present work makes use of time-resolved PIV to quantify the effects of streamwise spacing on the turbulent near wake throughout various pin-fin array spacings. Specifically, proper orthogonal decomposition was used to separate the (quasi-) periodic motion from vortex shedding and the random motion from turbulent eddies. Reynolds number flow conditions of 3.0 × 103 and 2.0 × 104, based on pin-fin diameter and velocity at the minimum flow area, were considered. Streamwise spacing was varied from 3.46 pin diameters to 1.73 pin diameters while the pin-fin height-to-diameter ratio was unity and the spanwise spacing was held constant at two diameters. Results indicated that (quasi-) periodic motions were attenuated at closer streamwise spacings while the level of random motions was not strongly dependent on pin-fin spacing. This trend was observed at both Reynolds number conditions considered. Because closer spacings exhibit higher heat transfer levels, the present results imply that periodic motions may not contribute to heat transfer, although further experimentation is required.

  3. KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F Star

    CERN Document Server

    Siverd, Robert J; Pepper, Joshua; Eastman, Jason D; Collins, Karen; Bieryla, Allyson; Latham, David W; Buchhave, Lars A; Jensen, Eric L N; Crepp, Justin R; Street, Rachel; Stassun, Keivan G; Gaudi, B Scott; Berlind, Perry; Calkins, Michael L; DePoy, D L; Esquerdo, Gilbert A; Fulton, Benjamin J; Furesz, Gabor; Geary, John C; Gould, Andrew; Hebb, Leslie; Kielkopf, John F; Marshall, Jennifer L; Pogge, Richard; Stanek, K Z; Stefanik, Robert P; Szentgyorgyi, Andrew H; Trueblood, Mark; Trueblood, Patricia; Stutz, Amelia M; van Saders, Jennifer L

    2012-01-01

    We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. The companion is a low-mass brown dwarf or super-massive planet with mass of 27.23+/-0.50 MJ and radius of 1.110+0.037-0.024 RJ, on a very short period (P=1.21750007) circular orbit. KELT-1b receives a large amount of stellar insolation, with an equilibrium temperature assuming zero albedo and perfect redistribution of 2422 K. Upper limits on the secondary eclipse depth indicate that either the companion must have a non-zero albedo, or it must experience some energy redistribution. Comparison with standard evolutionary models for brown dwarfs suggests that the radius of KELT-1b is significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1, which is consistent with an M dwarf if bound. The projected spin-orbit alignment angle is consistent with ...

  4. A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass-Radius Relationship for M Dwarfs

    Science.gov (United States)

    Lubin, Jack B.; Rodriguez, Joseph E.; Zhou, George; Conroy, Kyle E.; Stassun, Keivan G.; Collins, Karen; Stevens, Daniel J.; Labadie-Bartz, Jonathan; Stockdale, Christopher; Myers, Gordon; Colón, Knicole D.; Bento, Joao; Kehusmaa, Petri; Petrucci, Romina; Jofré, Emiliano; Quinn, Samuel N.; Lund, Michael B.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.; Harlingten, Caisey; Pepper, Joshua; Gaudi, B. Scott; James, David; Jensen, Eric L. N.; Reichart, Daniel; Kedziora-Chudczer, Lucyna; Bailey, Jeremy; Melville, Graeme

    2017-08-01

    We report the discovery of KELT J041621-620046, a moderately bright (J ˜ 10.2) M-dwarf eclipsing binary system at a distance of 39 ± 3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extremely Little Telescope (KELT) survey. The system has a short orbital period of ˜1.11 days and consists of components with {M}1={0.447}+0.052-0.047 {M}⊙ and {M}2={0.399}+0.046-0.042 {M}⊙ in nearly circular orbits. The radii of the two stars are {R}1={0.540}+0.034-0.032 {R}⊙ and {\\text{}}{R}2=0.453+/- 0.017 {R}⊙ . Full system and orbital properties were determined (to ˜10% error) by conducting an EBOP (Eclipsing Binary Orbit Program) global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17%-28% and cooler by 4%-10% than predicted by standard (non-magnetic) stellar models. Strong Hα emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.

  5. Persistent photoconductivity in uniforndy and selectively silicon doped AlAs / GaAs short period superlattices

    Science.gov (United States)

    Jeanjean, P.; Sicart, J.; Robert, J. L.; Mollot, F.; Planel, R.

    1991-04-01

    Hall and photo-Hall measurements have been carried out between 4 K et 400 K on MBE deposited AlAs / GaAs superiattices (SPS) with short period (25 Å dopage uniforme, alors que les SPS dopées sélectivement dans GaAs ne présentent qu'une seule barrière (un seul plateau). Ainsi la microstructure GaAs / AlAs apparaît être un outil particulièrement intéressant pour confirmer la validité du modèle multibarrière proposé récemment pour le centre DX dans AlxGal{1-x} As: Si.

  6. Optical properties of spontaneous lateral composition modulations in AlAs/InAs short-period superlattices

    Energy Technology Data Exchange (ETDEWEB)

    FRANCOEUR,S.; ALSINA,F.; ZHANG,YONG; NORMAN,A.G.; MASCARENHAS,A.; JONES,ERIC D.; RENO,JOHN L.; LEE,STEPHEN R.; FOLLSTAEDT,DAVID M.

    2000-05-11

    The effect of lateral composition modulation, spontaneously generated during the epitaxial growth of a AlAs/InAs short-period superlattice, on the electronic band structure is investigated using photo-transmission and photoluminescence spectroscopy. Compared with uniform layers of similar average composition, the presence of the composition modulation considerably reduces the band gap energy and produces strongly polarized emission and absorption spectra. The authors demonstrate that the dominant polarization can selectively be aligned along the [{bar 1}10] or [010] crystallographic directions. In compressively strained samples, the use of (001) InP substrates slightly miscut toward [111]A or [101] resulted in modulation directions along [110] or [100], respectively, and dominant polarizations along a direction orthogonal to the respective composition modulation. Band gap reduction as high as 350 meV and 310 meV are obtained for samples with composition modulation along [110] and [100], respectively. Polarization ratios up to 26 are observed in transmission spectra.

  7. Quasi-periodic oscillations in short recurring bursts of the soft gamma repeater J1550–5418

    Energy Technology Data Exchange (ETDEWEB)

    Huppenkothen, D.; D' Angelo, C.; Watts, A. L.; Heil, L.; Van der Klis, M.; Van der Horst, A. J. [Astronomical Institute " Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Kouveliotou, C. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Göğüş, E.; Kaneko, Y. [SabancıUniversity, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra' anana 43537 (Israel); Lin, L. [François Arago Centre, APC, 10 rue Alice Domon et Léonie Duquet, F-75205 Paris (France); Von Kienlin, A. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Younes, G., E-mail: D.Huppenkothen@uva.nl [NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States)

    2014-06-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. The scarcity of giant flares makes a search for QPOs in the shorter, far more numerous bursts from soft gamma repeaters (SGRs) desirable. In Huppenkothen et al., we developed a Bayesian method for searching for QPOs in short magnetar bursts, taking into account the effects of the complicated burst structure, and have shown its feasibility on a small sample of bursts. Here we apply the same method to a much larger sample from a burst storm of 286 bursts from SGR J1550–5418. We report a candidate signal at 260 Hz in a search of the individual bursts, which is fairly broad. We also find two QPOs at ∼93 Hz, and one at 127 Hz, when averaging periodograms from a number of bursts in individual triggers, at frequencies close to QPOs previously observed in magnetar giant flares. Finally, for the first time, we explore the overall burst variability in the sample and report a weak anti-correlation between the power-law index of the broadband model characterizing aperiodic burst variability and the burst duration: shorter bursts have steeper power-law indices than longer bursts. This indicates that longer bursts vary over a broader range of timescales and are not simply longer versions of the short bursts.

  8. Short term Variability of the Sun Earth System: An Overview of Progress Made during the CAWSES II Period

    CERN Document Server

    Gopalswamy, Nat; Yan, Yihua

    2015-01-01

    This paper presents an overview of results obtained during the CAWSES II period on the short term variability of the Sun and how it affects the near Earth space environment. CAWSES II was planned to examine the behavior of the solar terrestrial system as the solar activity climbed to its maximum phase in solar cycle 24. After a deep minimum following cycle 23, the Sun climbed to a very weak maximum in terms of the sunspot number in cycle 24 (MiniMax24), so many of the results presented here refer to this weak activity in comparison with cycle 23. The short term variability that has immediate consequence to Earth and geospace manifests as solar eruptions from closed field regions and high speed streams from coronal holes. Both electromagnetic (flares) and mass emissions (coronal mass ejections, CMEs) are involved in solar eruptions, while coronal holes result in high speed streams that collide with slow wind forming the so called corotating interaction regions (CIRs). Fast CMEs affect Earth via leading shocks ...

  9. Spreading depression is facilitated in adult rats previously submitted to short episodes of malnutrition during the lactation period

    Directory of Open Access Journals (Sweden)

    Rocha-de-Melo A.P.

    1997-01-01

    Full Text Available Lactating rat dams were submitted to short episodes (1, 2 or 3 weeks of nutritional restriction by receiving the "regional basic diet" (RBD, with 8% protein of low-income human populations of Northeast Brazil. Their pups were then studied regarding the developmental effects on body and brain weights. When the rats reached adulthood, cortical susceptibility to the phenomenon of spreading depression (SD was evaluated by performing electrophysiological recordings on the surface of the cerebral cortex. SD was elicited at 20-min intervals by applying 2% KCl for 1 min to a site on the frontal cortex and its occurrence was monitored at 2 sites in the parietal region by recording the electrocorticogram and the slow potential change of SD. When compared to control rats fed a commercial diet with 23% protein, early malnourished rats showed deficits in body and brain weights (10% to 60% and 3% to 15%, respectively, as well as increases in velocity of SD propagation (10% to 20%. These effects were directly related to the duration of maternal dietary restriction, with pups malnourished for 2 or 3 weeks presenting more intense weight and SD changes than those malnourished for 1 week. The effects of 1-week restrictions on SD were less evident in the pups malnourished during the second week of lactation and were more evident in pups receiving the RBD during the third week. The results indicate that short episodes of early malnutrition during the suckling period can affect body and brain development, as well as the cortical susceptibility to SD during adulthood. The data also suggest that the third week of lactation is the period during which the brain is most sensitive to malnutrition, concerning the effects on SD

  10. Long-term trends and extremes in observed daily precipitation and near surface air temperature in the Philippines for the period 1951-2010

    Science.gov (United States)

    Cinco, Thelma A.; de Guzman, Rosalina G.; Hilario, Flaviana D.; Wilson, David M.

    2014-08-01

    Observed daily precipitation and near surface air temperature data from 34 synoptic weather stations in the Philippines for the period 1951-2010 were subjected to trend analysis which revealed an overall warming tendency compared to the normal mean values for the period 1961-1990. This warming trend can be observed in the annual mean temperatures, daily minimum mean temperatures and to a lesser extent, daily maximum mean temperatures. Precipitation and temperature extremes for the period 1951-2010 were also analysed relative to the mean 1961-1990 baseline values. Some stations (Cotabato, Iloilo, Laoag and Tacloban,) show increases in both frequency and intensity of extreme daily rainfall events which are significant at the 95% level with none of the stations showing decreasing trends. The frequency of daily temperature maximum above the 99th percentile (hot days) and nights at the 1st percentile (cold nights) suggests that both days and nights in particular are becoming warmer. Such indicators of a warming trend and increase in extreme events in the Philippines are discussed in the context of similar national, regional (Asia Pacific) and global studies. The relevance of such empirically based climatology studies, particularly for nations such as the Philippines which are increasingly vulnerable to the multiple impacts of global climate change, is also considered.

  11. Short period forecasting of catchment-scale precipitation. Part II: a water-balance storm model for short-term rainfall and flood forecasting

    Directory of Open Access Journals (Sweden)

    V. A. Bell

    2000-01-01

    Full Text Available A simple two-dimensional rainfall model, based on advection and conservation of mass in a vertical cloud column, is investigated for use in short-term rainfall and flood forecasting at the catchment scale under UK conditions. The model is capable of assimilating weather radar, satellite infra-red and surface weather observations, together with forecasts from a mesoscale numerical weather prediction model, to obtain frequently updated forecasts of rainfall fields. Such data assimilation helps compensate for the simplified model dynamics and, taken together, provides a practical real-time forecasting scheme for catchment scale applications. Various ways are explored for using information from a numerical weather prediction model (16.8 km grid within the higher resolution model (5 km grid. A number of model variants is considered, ranging from simple persistence and advection methods used as a baseline, to different forms of the dynamic rainfall model. Model performance is assessed using data from the Wardon Hill radar in Dorset for two convective events, on 10 June 1993 and 16 July 1995, when thunderstorms occurred over southern Britain. The results show that (i a simple advection-type forecast may be improved upon by using multiscan radar data in place of data from the lowest scan, and (ii advected, steady-state predictions from the dynamic model, using 'inferred updraughts', provides the best performance overall. Updraught velocity is inferred at the forecast origin from the last two radar fields, using the mass-balance equation and associated data and is held constant over the forecast period. This inference model proves superior to the buoyancy parameterisation of updraught employed in the original formulation. A selection of the different rainfall forecasts is used as input to a catchment flow forecasting model, the IH PDM (Probability Distributed Moisture model, to assess their effect on flow forecast accuracy for the 135 km2 Brue catchment

  12. MARVELS-1b: A Short-Period, Brown Dwarf Desert Candidate from the SDSS-III MARVELS Planet Search

    CERN Document Server

    Lee, Brian L; Fleming, Scott W; Stassun, Keivan G; Gaudi, B Scott; Barnes, Rory; Mahadevan, Suvrath; Eastman, Jason D; Wright, Jason; Siverd, Robert J; Gary, Bruce; Ghezzi, Luan; Laws, Chris; Wisniewski, John P; de Mello, G F Porto; Ogando, Ricardo L C; Maia, Marcio A G; da Costa, Luiz Nicolaci; Sivarani, Thirupathi; Pepper, Joshua; Nguyen, Duy Cuong; Hebb, Leslie; De Lee, Nathan; Wang, Ji; Wan, Xiaoke; Zhao, Bo; Chang, Liang; Groot, John; Varosi, Frank; Hearty, Fred; Hanna, Kevin; van Eyken, J C; Kane, Stephen R; Agol, Eric; Bizyaev, Dmitry; Bochanski, John J; Brewington, Howard; Chen, Zhiping; Costello, Erin; Dou, Liming; Eisenstein, Daniel J; Fletcher, Adam; Ford, Eric B; Guo, Pengcheng; Holtzman, Jon A; Jiang, Peng; Leger, R French; Liu, Jian; Long, Daniel C; Malanushenko, Elena; Malanushenko, Viktor; Malik, Mohit; Oravetz, Daniel; Pan, Kaike; Rohan, Pais; Schneider, Donald P; Shelden, Alaina; Snedden, Stephanie A; Simmons, Audrey; Weaver, B A; Weinberg, David H; Xie, Ji-Wei

    2010-01-01

    We present a new short-period brown dwarf candidate around the star TYC 1240-00945-1. This candidate was discovered in the first year of the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the third phase of the Sloan Digital Sky Survey (SDSS-III), and we designate the brown dwarf as MARVELS-1b. MARVELS uses the technique of dispersed fixed-delay interferometery to simultaneously obtain radial velocity measurements for 60 objects per field using a single, custom-built instrument that is fiber fed from the SDSS 2.5-m telescope. From our 20 radial velocity measurements spread over a ~370 d time baseline, we derive a Keplerian orbital fit with semi-amplitude K=2.533+/-0.025 km/s, period P=5.8953+/-0.0004 d, and eccentricity consistent with circular. Independent follow-up radial velocity data confirm the orbit. Adopting a mass of 1.37+/-0.11 M_Sun for the slightly evolved F9 host star, we infer that the companion has a minimum mass of 28.0+/-1.5 M_Jup, a semimajor axis 0....

  13. The OmegaWhite survey for Short-Period Variable Stars III: Follow-up Photometric and Spectroscopic Observations

    CERN Document Server

    Macfarlane, S A; Groot, P J; Ramsay, G; Toma, R; Motsoaledi, M; Crause, L A; Gilbank, D G; O'Donoghue, D; Potter, S B; Sickafoose, A A; van Gend, C; Worters, H L

    2016-01-01

    We present photometric and spectroscopic follow-up observations of short-period variables discovered in the OmegaWhite survey: a wide-field high-cadence g-band synoptic survey targeting the Galactic Plane. We have used fast photometry on the SAAO 1.0-m and 1.9-m telescopes to obtain light curves of 27 variables, and use these results to validate the period and amplitude estimates from the OmegaWhite processing pipeline. Furthermore, 57 sources (44 unique, 13 also with new light curves) were selected for spectroscopic follow-up using either the SAAO 1.9-m telescope or the Southern African Large Telescope. We find many of these variables have spectra which are consistent with being delta Scuti type pulsating stars. At higher amplitudes, we detect four possible pulsating white dwarf/subdwarf sources and an eclipsing cataclysmic variable. Due to their rarity, these targets are ideal candidates for detailed follow-up studies. From spectroscopy, we confirm the symbiotic binary star nature of two variables identifie...

  14. Constraining the formation of black holes in short-period black hole low-mass X-ray binaries

    Science.gov (United States)

    Repetto, Serena; Nelemans, Gijs

    2015-11-01

    The formation of stellar-mass black holes (BHs) is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova (SN) event (if any) and the magnitude of the natal kick (NK) the BH receives at birth (if any). Repetto et al., studying the position of Galactic X-ray binaries containing BHs, found evidence for BHs receiving high NKs at birth. In this paper, we extend that study, taking into account the previous binary evolution of the sources as well. The seven short-period BH X-ray binaries that we use are compact binaries consisting of a low-mass star orbiting a BH in a period less than 1 d. We trace their binary evolution backwards in time, from the current observed state of mass transfer, to the moment the BH was formed, and we add the extra information on the kinematics of the binaries. We find that several systems could be explained by no NK, just mass ejection, while for two systems (and possibly more) a high kick is required. So unless the latter have an alternative formation, such as within a globular cluster, we conclude that at least some BHs get high kicks. This challenges the standard picture that BH kicks would be scaled down from neutron star kicks. Furthermore, we find that five systems could have formed with a non-zero NK but zero mass ejected (i.e. no SN) at formation, as predicted by neutrino-driven NKs.

  15. The OmegaWhite survey for short-period variable stars - III: follow-up photometric and spectroscopic observations

    Science.gov (United States)

    Macfarlane, S. A.; Woudt, P. A.; Groot, P. J.; Ramsay, G.; Toma, R.; Motsoaledi, M.; Crause, L. A.; Gilbank, D. G.; O'Donoghue, D.; Potter, S. B.; Sickafoose, A. A.; van Gend, C.; Worters, H. L.

    2017-02-01

    We present photometric and spectroscopic follow-up observations of short-period variables discovered in the OmegaWhite survey, a wide-field high-cadence g-band synoptic survey targeting the Galactic Plane. We have used fast photometry on the SAAO 1.0- and 1.9-m telescopes to obtain light curves of 27 variables, and use these results to validate the period and amplitude estimates from the OmegaWhite processing pipeline. Furthermore, 57 sources (44 unique, 13 with new light curves) were selected for spectroscopic follow-up using either the SAAO 1.9-m telescope or the Southern African Large Telescope. We find that many of these variables have spectra which are consistent with being δ Scuti-type pulsating stars. At higher amplitudes, we detect four possible pulsating white dwarf/subdwarf sources and an eclipsing cataclysmic variable. Due to their rarity, these targets are ideal candidates for detailed follow-up studies. From spectroscopy, we confirm the symbiotic binary star nature of two variables identified as such in the SIMBAD database. We also report what could possibly be the first detection of the `Bump Cepheid' phenomena in a δ Scuti star, with OW J175848.21-271653.7 showing a pronounced 22 per cent amplitude dip lasting 3 min during each pulsational cycle peak. However, the precise nature of this target is still uncertain as it exhibits the spectral features of a B-type star.

  16. Comparative analysis of methods for modelling the short-term probability distribution of extreme wind turbine loads

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov

    2016-01-01

    We have tested the performance of statistical extrapolation methods in predicting the extreme response of a multi-megawatt wind turbine generator. We have applied the peaks-over-threshold, block maxima and average conditional exceedance rates (ACER) methods for peaks extraction, combined with four...... levels, based on the assumption that the response tail is asymptotically Gumbel distributed. Example analyses were carried out, aimed at comparing the different methods, analysing the statistical uncertainties and identifying the factors, which are critical to the accuracy and reliability...

  17. Persistence of pathogens with short infectious periods in seasonal tick populations: the relative importance of three transmission routes.

    Directory of Open Access Journals (Sweden)

    Etsuko Nonaka

    Full Text Available BACKGROUND: The flaviviruses causing tick-borne encephalitis (TBE persist at low but consistent levels in tick populations, despite short infectious periods in their mammalian hosts and transmission periods constrained by distinctly seasonal tick life cycles. In addition to systemic and vertical transmission, cofeeding transmission has been proposed as an important route for the persistence of TBE-causing viruses. Because cofeeding transmission requires ticks to feed simultaneously, the timing of tick activity may be critical to pathogen persistence. Existing models of tick-borne diseases do not incorporate all transmission routes and tick seasonality. Our aim is to evaluate the influence of seasonality on the relative importance of different transmission routes by using a comprehensive mathematical model. METHODOLOGY/PRINCIPAL FINDINGS: We developed a stage-structured population model that includes tick seasonality and evaluated the relative importance of the transmission routes for pathogens with short infectious periods, in particular Powassan virus (POWV and the related "deer tick virus," emergent encephalitis-causing flaviviruses in North America. We used the next generation matrix method to calculate the basic reproductive ratio and performed elasticity analyses. We confirmed that cofeeding transmission is critically important for such pathogens to persist in seasonal tick populations over the reasonable range of parameter values. At higher but still plausible rates of vertical transmission, our model suggests that vertical transmission can strongly enhance pathogen prevalence when it operates in combination with cofeeding transmission. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that the consistent prevalence of POWV observed in tick populations could be maintained by a combination of low vertical, intermediate cofeeding and high systemic transmission rates. When vertical transmission is weak, nymphal ticks support integral parts of

  18. MARVELS-1b: A Short-period, Brown Dwarf Desert Candidate from the SDSS-III Marvels Planet Search

    Science.gov (United States)

    Lee, Brian L.; Ge, Jian; Fleming, Scott W.; Stassun, Keivan G.; Gaudi, B. Scott; Barnes, Rory; Mahadevan, Suvrath; Eastman, Jason D.; Wright, Jason; Siverd, Robert J.; Gary, Bruce; Ghezzi, Luan; Laws, Chris; Wisniewski, John P.; Porto de Mello, G. F.; Ogando, Ricardo L. C.; Maia, Marcio A. G.; Nicolaci da Costa, Luiz; Sivarani, Thirupathi; Pepper, Joshua; Nguyen, Duy Cuong; Hebb, Leslie; De Lee, Nathan; Wang, Ji; Wan, Xiaoke; Zhao, Bo; Chang, Liang; Groot, John; Varosi, Frank; Hearty, Fred; Hanna, Kevin; van Eyken, J. C.; Kane, Stephen R.; Agol, Eric; Bizyaev, Dmitry; Bochanski, John J.; Brewington, Howard; Chen, Zhiping; Costello, Erin; Dou, Liming; Eisenstein, Daniel J.; Fletcher, Adam; Ford, Eric B.; Guo, Pengcheng; Holtzman, Jon A.; Jiang, Peng; French Leger, R.; Liu, Jian; Long, Daniel C.; Malanushenko, Elena; Malanushenko, Viktor; Malik, Mohit; Oravetz, Daniel; Pan, Kaike; Rohan, Pais; Schneider, Donald P.; Shelden, Alaina; Snedden, Stephanie A.; Simmons, Audrey; Weaver, B. A.; Weinberg, David H.; Xie, Ji-Wei

    2011-02-01

    We present a new short-period brown dwarf (BD) candidate around the star TYC 1240-00945-1. This candidate was discovered in the first year of the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III, and we designate the BD as MARVELS-1b. MARVELS uses the technique of dispersed fixed-delay interferometery to simultaneously obtain radial velocity (RV) measurements for 60 objects per field using a single, custom-built instrument that is fiber fed from the SDSS 2.5 m telescope. From our 20 RV measurements spread over a ~370 day time baseline, we derive a Keplerian orbital fit with semi-amplitude K = 2.533 ± 0.025 km s-1, period P = 5.8953 ± 0.0004 days, and eccentricity consistent with circular. Independent follow-up RV data confirm the orbit. Adopting a mass of 1.37 ± 0.11 M sun for the slightly evolved F9 host star, we infer that the companion has a minimum mass of 28.0 ± 1.5 M Jup, a semimajor axis 0.071 ± 0.002 AU assuming an edge-on orbit, and is probably tidally synchronized. We find no evidence for coherent intrinsic variability of the host star at the period of the companion at levels greater than a few millimagnitudes. The companion has an a priori transit probability of ~14%. Although we find no evidence for transits, we cannot definitively rule them out for companion radii lsim1 R Jup.

  19. The 5-minute Apgar score: survival and short-term outcomes in extremely low-birth-weight infants.

    Science.gov (United States)

    Phalen, Ann Gibbons; Kirkby, Sharon; Dysart, Kevin

    2012-01-01

    The Apgar score is a standardized tool for evaluating newborns in the delivery room. Despite its long history and widespread use, debate remains over its reliability of predicting neonatal outcomes, especially in extremely low-birth-weight premature infants. The aim of the study was to examine the relationship between the 5-minute Apgar score of extremely low-birth-weight infants, as it relates to survival and morbidities associated with prematurity and length of hospital stay. A retrospective query of the Alere neonatal database from 2001 to 2011 examined all infants less than 32 weeks' gestation and less than 1000-g birth weight. The 5-minute Apgar score was divided into 2 groups, score of 4 or greater or less than 4. The study compared results of the 5-minute Apgar score and associated morbidities in surviving infants. Statistical analyses included chi-square, Fisher exact test, t test, and multivariate regression. The sample consisted of 3898 infants with an 86.4% (n = 3366) survival rate. Controlling for gestational age and birth weight, surviving infants with a 5-minute Apgar score of less than 4 were more likely to demonstrate nonintact survival. Infants with a low 5-minute Apgar score have greater risk for mortality and morbidities associated with prematurity.

  20. Composition and fate of short-period super-Earths: The case of CoRoT-7b

    CERN Document Server

    Valencia, Diana; Guillot, Tristan; Nettelmann, Nadine

    2009-01-01

    Context. The discovery of CoRotT-7b, a planet of radius 1.68 +/- 0.09 R_Earth, with an orbital period of 0.854 days demonstrates that small planets can orbit extremely close to their star. Aims. Several questions arise concerning this planet, in particular concerning its possible composition, mass and fate. Methods. We use knowledge of hot Jupiters, mass loss estimates and models for the interior structure and evolution of planets to understand its composition, structure and evolution. Results. Although detailed modeling should address this problem, we show that a relatively significant mass loss ~10^11 g/s is to be expected, independently of the planet's composition. Given the closeness to the star, we find that the planet size is compatible with the observations only if the planet contains less than 1% of its mass in hydrogen and helium and less than 20% in steam. Due to the significant evaporation rate, it is most likely that the planet is made only of iron and silicates, which implies that its mass should...

  1. Factors affecting the thermal environment of Agassiz’s Desert Tortoise (Gopherus agassizii) cover sites in the Central Mojave Desert during periods of temperature extremes

    Science.gov (United States)

    Mack, Jeremy S.; Berry, Kristin H.; Miller, David; Carlson, Andrea S.

    2015-01-01

    Agassiz's Desert Tortoises (Gopherus agassizii) spend >95% of their lives underground in cover sites that serve as thermal buffers from temperatures, which can fluctuate >40°C on a daily and seasonal basis. We monitored temperatures at 30 active tortoise cover sites within the Soda Mountains, San Bernardino County, California, from February 2004 to September 2006. Cover sites varied in type and structural characteristics, including opening height and width, soil cover depth over the opening, aspect, tunnel length, and surficial geology. We focused our analyses on periods of extreme temperature: in summer, between July 1 and September 1, and winter, between November 1 and February 15. With the use of multivariate regression tree analyses, we found cover-site temperatures were influenced largely by tunnel length and subsequently opening width and soil cover. Linear regression models further showed that increasing tunnel length increased temperature stability and dampened seasonal temperature extremes. Climate change models predict increased warming for southwestern North America. Cover sites that buffer temperature extremes and fluctuations will become increasingly important for survival of tortoises. In planning future translocation projects and conservation efforts, decision makers should consider habitats with terrain and underlying substrate that sustain cover sites with long tunnels and expanded openings for tortoises living under temperature extremes similar to those described here or as projected in the future.

  2. Predicted detection rates of regional-scale meteorite impacts on Mars with the InSight short-period seismometer

    Science.gov (United States)

    Teanby, N. A.

    2015-08-01

    In 2016 NASA will launch the InSight discovery-class mission, which aims to study the detailed internal structure of Mars for the first time. Short- and long-period seismometers form a major component of InSight's payload and have the potential to detect seismic waves generated by meteorite impacts. Large globally detectable impact events producing craters with diameters of ∼ 100 m have been investigated previously and are likely to be rare (Teanby, N.A., Wookey, J. [2011]. Phys. Earth Planet. Int. 186, 70-80), but smaller impacts producing craters in the 0.5-20 m range are more numerous and potentially occur sufficiently often to be detectable on regional scales (≲1000 km). At these distances, seismic waves will have significant high frequency content and will be suited to detection with InSight's short-period seismometer SEIS-SP. In this paper I estimate the current martian crater production function from observations of new craters (Malin, M.C. et al. [2006]. Science 314, 1573-1577; Daubar, I.J. et al. [2013]. Icarus 225, 506-516), model results (Williams, J.P., Pathare, A.V., Aharonson, O. [2014]. Icarus 235, 23-36), and standard isochrons (Hartmann, W.K. [2005]. Icarus 174, 294-320). These impact rates are combined with an empirical relation between impact energy, source-receiver distance, and peak seismogram amplitude, derived from a compilation of seismic recordings of terrestrial and lunar impacts, chemical explosions, and nuclear tests. The resulting peak seismogram amplitude scaling law contains significant uncertainty, but can be used to predict impact detection rates. I estimate that for a short-period instrument, with a noise spectral density of 10-8 ms-2 Hz-1/2 in the 1-16 Hz frequency band, approximately 0.1-30 regional impacts per year should be detectable with a nominal value of 1-3 impacts per year. Therefore, small regional impacts are likely to be a viable source of seismic energy for probing Mars' crustal and upper mantle structure. This is

  3. Hybrid Short Term Wind Speed Forecasting Using Variational Mode Decomposition and a Weighted Regularized Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Nantian Huang

    2016-11-01

    Full Text Available Accurate wind speed forecasting is a fundamental element of wind power prediction. Thus, a new hybrid wind speed forecasting model, using variational mode decomposition (VMD, the partial autocorrelation function (PACF, and weighted regularized extreme learning machine (WRELM, is proposed to improve the accuracy of wind speed forecasting. First, the historic wind speed time series is decomposed into several intrinsic mode functions (IMFs. Second, the partial correlation of each IMF sequence is analyzed using PACF to select the optimal subfeature set for particular predictors of each IMF. Then, the predictors of each IMF are constructed in order to enhance its strength using WRELM. Finally, wind speed is obtained by adding up all the predictors. The experiment, using real wind speed data, verified the effectiveness and advancement of the new approach.

  4. Targeted identification of short interspersed nuclear element families shows their widespread existence and extreme heterogeneity in plant genomes.

    Science.gov (United States)

    Wenke, Torsten; Döbel, Thomas; Sörensen, Thomas Rosleff; Junghans, Holger; Weisshaar, Bernd; Schmidt, Thomas

    2011-09-01

    Short interspersed nuclear elements (SINEs) are non-long terminal repeat retrotransposons that are highly abundant, heterogeneous, and mostly not annotated in eukaryotic genomes. We developed a tool designated SINE-Finder for the targeted discovery of tRNA-derived SINEs. We analyzed sequence data of 16 plant genomes, including 13 angiosperms and three gymnosperms and identified 17,829 full-length and truncated SINEs falling into 31 families showing the widespread occurrence of SINEs in higher plants. The investigation focused on potato (Solanum tuberosum), resulting in the detection of seven different SolS SINE families consisting of 1489 full-length and 870 5' truncated copies. Consensus sequences of full-length members range in size from 106 to 244 bp depending on the SINE family. SolS SINEs populated related species and evolved separately, which led to some distinct subfamilies. Solanaceae SINEs are dispersed along chromosomes and distributed without clustering but with preferred integration into short A-rich motifs. They emerged more than 23 million years ago and were species specifically amplified during the radiation of potato, tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum). We show that tobacco TS retrotransposons are composite SINEs consisting of the 3' end of a long interspersed nuclear element integrated downstream of a nonhomologous SINE family followed by successfully colonization of the genome. We propose an evolutionary scenario for the formation of TS as a spontaneous event, which could be typical for the emergence of SINE families.

  5. Targeted Identification of Short Interspersed Nuclear Element Families Shows Their Widespread Existence and Extreme Heterogeneity in Plant Genomes[W

    Science.gov (United States)

    Wenke, Torsten; Döbel, Thomas; Sörensen, Thomas Rosleff; Junghans, Holger; Weisshaar, Bernd; Schmidt, Thomas

    2011-01-01

    Short interspersed nuclear elements (SINEs) are non-long terminal repeat retrotransposons that are highly abundant, heterogeneous, and mostly not annotated in eukaryotic genomes. We developed a tool designated SINE-Finder for the targeted discovery of tRNA-derived SINEs. We analyzed sequence data of 16 plant genomes, including 13 angiosperms and three gymnosperms and identified 17,829 full-length and truncated SINEs falling into 31 families showing the widespread occurrence of SINEs in higher plants. The investigation focused on potato (Solanum tuberosum), resulting in the detection of seven different SolS SINE families consisting of 1489 full-length and 870 5′ truncated copies. Consensus sequences of full-length members range in size from 106 to 244 bp depending on the SINE family. SolS SINEs populated related species and evolved separately, which led to some distinct subfamilies. Solanaceae SINEs are dispersed along chromosomes and distributed without clustering but with preferred integration into short A-rich motifs. They emerged more than 23 million years ago and were species specifically amplified during the radiation of potato, tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum). We show that tobacco TS retrotransposons are composite SINEs consisting of the 3′ end of a long interspersed nuclear element integrated downstream of a nonhomologous SINE family followed by successfully colonization of the genome. We propose an evolutionary scenario for the formation of TS as a spontaneous event, which could be typical for the emergence of SINE families. PMID:21908723

  6. Short-term maternal psychological stress in the post-conception period in ewes affects fetal growth and gestation length.

    Science.gov (United States)

    Smith, Jennifer; Ferguson, Drewe; Jauregui, Guillermo; Panarace, Martín; Medina, Mariano; Lehnert, Sigrid; Hill, Jonathan R

    2008-08-01

    Fetal development can be influenced by maternal environment in the peri-conceptional period. This study investigated the effect of maternal feed intake and psychological stress within the first 6 days after conception on embryo development and fetal growth. Superovulated ewes (n=40) were artificially inseminated with semen from one ram. Ewes were then divided into four groups (n=10): group 1 (control) was fed at maintenance level, group 2 (high) at 2x maintenance, and group 3 (low) at 0.5x maintenance on days 2-6 after conception. Group 4 (stress) was fed at maintenance level and then an intense physical and psychological stress challenge was applied for 1 h only on days 2 and 3 after conception. Embryos were recovered at day 6. A total of 113 transferable grade embryos were transferred singly into synchronized untreated recipients, while the remaining embryos (n=165) were fixed and stained for cell counts. Post-conception maternal stress or feed intake did not alter the cell count or grade of day 6 embryos. Fetuses from the stress group had longer crown-rump lengths at day 30 and longer femur length at day 58. Fetuses from the stressed and high feed groups had greater abdominal circumferences at day 85. Subsequent birth weights were not significantly different. Ewes carrying lambs from the stress treatment had shorter gestation lengths. These results show that short-term perturbations of the post-conception maternal environment have measurable effects on fetal development and gestation length.

  7. HD 174884: a strongly eccentric, short-period early-type binary system discovered by CoRoT

    CERN Document Server

    Maceroni, C; Michel, E; Harmanec, P; Prsa, A; Briquet, M; Niemczura, E; Morel, T; Ladjal, D; Auvergne, M; Baglin, A; Baudin, F; Catala, C; Samadi, R; Aerts, C

    2009-01-01

    Accurate photometric CoRoT space observations of a secondary seismological target, HD 174884, led to the discovery that this star is an astrophysically important double-lined eclipsing spectroscopic binary in an eccentric orbit (e of about 0.3), unusual for its short (3.65705d) orbital period. The high eccentricity, coupled with the orientation of the binary orbit in space, explains the very unusual observed light curve with strongly unequal primary and secondary eclipses having the depth ratio of 1-to-100 in the CoRoT 'seismo' passband. Without the high accuracy of the CoRoT photometry, the secondary eclipse, 1.5 mmag deep, would have gone unnoticed. A spectroscopic follow-up program provided 45 high dispersion spectra. The analysis of the CoRoT light curve was performed with an adapted version of PHOEBE that supports CoRoT passbands. The final solution was obtained by simultaneous fitting of the light and the radial velocity curves. Individual star spectra were derived by spectrum disentangling. The uncerta...

  8. WASP-44b, WASP-45b and WASP-46b: three short-period, transiting extrasolar planets

    CERN Document Server

    Anderson, D R; Gillon, M; Hellier, C; Jehin, E; Lendl, M; Maxted, P F L; Queloz, D; Smalley, B; Smith, A M S; Triaud, A H M J; West, R G; Pepe, F; Pollacco, D; Ségransan, D; Todd, I; Udry, S

    2011-01-01

    We report the discovery of three extrasolar planets that transit their moderately bright (Vmag = 12-13) host stars. WASP-44b is a 0.89-MJup planet in a 2.42-day orbit around a G8V star. WASP-45b is a 1.03-MJup planet which passes in front of the limb of its K2V host star every 3.13 days. Weak Ca H+K emission seen in the spectra of WASP-45 suggests the star is chromospherically active. WASP-46b is a 2.10-MJup planet in a 1.43-day orbit around a G6V star. Rotational modulation of the light curves of WASP-46 and weak Ca H+K emission in its spectra show the star to be photospherically and chromospherically active. We imposed circular orbits in our analyses as the radial velocity data are consistent with (near-)circular orbits, as could be expected from both empirical and tidal-theory perspectives for such short-period, Jupiter-mass planets. We discuss the impact of fitting for eccentric orbits for these type of planets when not supported by the data. The derived planetary and stellar radii depend on the fitted ec...

  9. Nature of short-period microtremors on the cliff-like ground. Part 4; Gakechi kinbo no tanshuki bido. 4

    Energy Technology Data Exchange (ETDEWEB)

    Maiguma, T.; Yoshiike, T. [Waseda University, Tokyo (Japan). School of Science and Engineering

    1996-10-01

    Microtremors were measured on the cliff-like ground with a height about 10 m, to examine the vibration characteristics. Test field-1 near Akabane, Kita-ku, Tokyo is located in a part of Musashino plateau covered with Kanto loam on its surface, and has relatively sound ground. Test field-2 at Machida is located in the western part of Tama hills, and also has Kanto loam on its surface. For the cliff-like ground with inclined angle 70{degree} at Akabane, remarkably predominant frequency 3.2 Hz was observed for the microtremors in the direction perpendicular to the cliff surface. However, this predominant vibration did not become larger due to the damping effects of the reinforcement walls near the end of cliff and the large trees on the cliff. Influence of the cliff-like ground was scarcely observed in the microtremors spectrum in both the directions parallel and vertical to the cliff-surface. From the observation of microtremors with short period on the cliff-like ground with inclined angle around 32{degree} at Machida, influence of cliff-like ground was not observed in the microtremors spectrum in all of the vibrating directions perpendicular, parallel and vertical to the cliff surface. 3 refs., 10 figs.

  10. Quasi-Periodic Oscillations in Short Recurring Bursts of the Soft-Gamma Repeater J1550-5418

    CERN Document Server

    Huppenkothen, Daniela; Watts, Anna L; Heil, Lucy; van der Klis, Michiel; van der Horst, Alexander J; Kouveliotou, Chryssa; Baring, Matthew G; Gogus, Ersin; Granot, Jonathan; Kaneko, Yuki; Lin, Lin; von Kienlin, Andreas; Younes, George

    2014-01-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. The scarcity of giant flares makes a search for QPOs in the shorter, far more numerous bursts from Soft Gamma Repeaters (SGRs) desirable. In Huppenkothen et al (2013), we developed a Bayesian method for searching for QPOs in short magnetar bursts, taking into account the effects of the complicated burst structure, and have shown its feasibility on a small sample of bursts. Here, we apply the same method to a much larger sample from a burst storm of 286 bursts from SGR J1550-5418. We report a candidate signal at 260 Hz in a search of the individual bursts, which is fairly broad. We also find two QPOs at 93 Hz and one at 127 Hz, when averaging periodograms from a number of bursts in individual triggers, at frequencies close to QPOs previously observed in magnetar giant flares. Finally, for the first time, we explore the overall burst variability in the sample, and report a weak...

  11. The OmegaWhite Survey for short period variable stars II: An overview of results from the first four years

    CERN Document Server

    Toma, Ruxandra; MacFarlane, Sally; Groot, Paul; Woudt, Patrick; Dhillon, Vik; Jeffery, C Simon; Marsh, Tom; Nelemans, Gijs; Steeghs, Danny

    2016-01-01

    OmegaWhite is a wide-field, high cadence, synoptic survey targeting fields in the southern Galactic plane, with the aim of discovering short period variable stars. Our strategy is to take a series of 39 s exposures in the g band of a 1 square degree of sky lasting 2 h using the OmegaCAM wide field imager on the VLT Survey Telescope (VST). We give an overview of the initial 4 years of data which covers 134 square degrees and includes 12.3 million light curves. As the fields overlap with the VLT Survey Telescope Halpha Photometric Survey of the Galactic plane and Bulge (VPHAS+), we currently have $ugriH\\alpha$ photometry for ~1/3 of our fields. We find that a significant fraction of the light curves have been affected by the diffraction spikes of bright stars sweeping across stars within a few dozen of pixels over the two hour observing time interval due to the alt-az nature of the VST. We select candidate variable stars using a variety of variability statistics, followed by a manual verification stage. We pres...

  12. The TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b

    CERN Document Server

    Gillon, M; Fortney, J J; Demory, B -O; Jehin, E; Lendl, M; Magain, P; Kabath, P; Queloz, D; Alonso, R; Anderson, D R; Cameron, A Collier; Fumel, A; Hebb, L; Hellier, C; Lanotte, A; Maxted, P F L; Mowlavi, N; Smalley, B

    2012-01-01

    We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b, in addition to eight new measurements of the radial velocity of the star. Thanks to this extensive data set, we improve significantly the parameters of the system. Notably, the largely improved precision on the stellar density (2.41+-0.08 rho_sun) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper. The resulting stellar mass and size are 0.717+-0.025 M_sun and 0.667+-0.011 R_sun. Our deduced physical parameters for the planet are 2.034+-0.052 M_jup and 1.036+-0.019 R_jup. Taking into account its level of irradiation, the high density of the planet favors an old age and a massive core. Our deduced orbital eccentricity, 0.0035(-0.0025,+0.0060), is consistent with a fully circularized orbit. We detect the emission of the planet at 2.09 microns at better than 11-sigma, the deduced occ...

  13. Desert Dwellers and Dynamic Duos: Short-Period Brown Dwarf Companions and Binary Science with Exoplanet Surveys

    Science.gov (United States)

    Fleming, Scott W.; Ge, J.

    2011-01-01

    Exoplanet transit and Doppler surveys detect many binary stars and brown dwarf companions with relative ease because the observational signatures are 1-2 orders of magnitude larger than planets. These objects allow for studies of several ancillary science topics, such as the two brown dwarf deserts and the mass-radius relationship of stars. In this dissertation talk, I will present my thesis work on conducting these studies using data from the MARVELS survey and several transit survey databases. I will present the discovery of two short-period (P MARVELS survey and its Pilot Project. Although I will focus on these two brown dwarfs, the MARVELS survey has already discovered a dozen brown dwarf companions that will serve to characterize the dryness of the brown dwarf deserts. These discoveries are needed to better understand brown dwarf formation and dynamical evolution histories. I will then present results from my work on cross-referencing spectroscopic binaries found in the MARVELS survey with archival photometry to conduct studies of the mass-radius relationship. Finally, I will present spectroscopic observations of known eclipsing binaries from transit surveys using the EXPERT instrument at the KPNO 2.1m telescope.

  14. Nature of short-period microtremors on the cliff-like ground. 3; Gakechi kinbo no tanshuki bido . 3

    Energy Technology Data Exchange (ETDEWEB)

    Maiguma, T.; Matsuzawa, H. [Saitama University, Saitama (Japan). Faculty of Engineering

    1996-05-01

    Vibration characteristics were investigated of the ground in the vicinity of a cliff-like sharp slope. Short-period microtremors were observed in the vicinity of an artificially made cliff-like test ground, height 8m and inclination 90{degree}, and a natural cliff, height approximately 9m and inclination approximately 35{degree}. The artificial cliff was reinforced by a virtually vertical retaining wall of concrete, and the ground was prepared for testing with a belt approximately 20m wide and 50m long along the cliff face. All the vibration components were simultaneously measured at measuring spots that were located 5-40m apart from the cliff end and orientated perpendicular to the cliff face. It was then found that in case of artificial cliff there is a conspicuous 3.1Hz prevalent ground vibration in the component squarely meeting the cliff face, that the prevalent ground vibration is not particularly great near the cliff end because the retaining wall and the ground are artificially prepared, that there is no influence of the cliff-like ground in the ground vibration parallel to or vertical along the cliff face, and that in case of natural ground there are no vibration characteristic proper to a cliff-like ground in any of the vibration components. 3 refs., 7 figs.

  15. A Case of Cellular Fibrous Histiocytoma on the Right Elbow with Repeated Relapse within a Short Period

    Directory of Open Access Journals (Sweden)

    Kanako Tsunoda

    2015-01-01

    Full Text Available Cellular fibrous histiocytoma, a variant of fibrous histiocytoma, is a designation used for lesions showing increased cellularity with a fascicular growth pattern and frequent extension into the subcutis. Here we describe a case of cellular fibrous histiocytoma showing repeated recurrence in a 36-year-old woman who initially presented with a 2-cm cutaneous tumor on her right elbow. Histopathologically, the first resected specimen demonstrated irregularly arranged collagen fibers mixed with scattered proliferating plump to spindle-shaped fibrohistiocytes. However, examination of the resected specimens obtained after recurrence showed that the cellularity had increased, the spindle-shaped cells showing monomorphic proliferation with a fascicular and storiform growth pattern extending into the subcutis, as well as an increase of Ki-67 positivity. Since the lesion showed repeated relapse within a short period, we performed wide-field resection of the tumor with a 3-cm margin. Currently, 48 months after surgery, there has been no local recurrence or metastasis, but continuous strict follow-up will be necessary.

  16. Short-Term Distribution System State Forecast Based on Optimal Synchrophasor Sensor Placement and Extreme Learning Machine

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Huaiguang; Zhang, Yingchen

    2016-11-14

    This paper proposes an approach for distribution system state forecasting, which aims to provide an accurate and high speed state forecasting with an optimal synchrophasor sensor placement (OSSP) based state estimator and an extreme learning machine (ELM) based forecaster. Specifically, considering the sensor installation cost and measurement error, an OSSP algorithm is proposed to reduce the number of synchrophasor sensor and keep the whole distribution system numerically and topologically observable. Then, the weighted least square (WLS) based system state estimator is used to produce the training data for the proposed forecaster. Traditionally, the artificial neural network (ANN) and support vector regression (SVR) are widely used in forecasting due to their nonlinear modeling capabilities. However, the ANN contains heavy computation load and the best parameters for SVR are difficult to obtain. In this paper, the ELM, which overcomes these drawbacks, is used to forecast the future system states with the historical system states. The proposed approach is effective and accurate based on the testing results.

  17. Anisotropic Lithospheric layering in the North American craton, revealed by Bayesian inversion of short and long period data

    Science.gov (United States)

    Roy, Corinna; Calo, Marco; Bodin, Thomas; Romanowicz, Barbara

    2016-04-01

    Competing hypotheses for the formation and evolution of continents are highly under debate, including the theory of underplating by hot plumes or accretion by shallow subduction in continental or arc settings. In order to support these hypotheses, documenting structural layering in the cratonic lithosphere becomes especially important. Recent studies of seismic-wave receiver function data have detected a structural boundary under continental cratons at 100-140 km depths, which is too shallow to be consistent with the lithosphere-asthenosphere boundary, as inferred from seismic tomography and other geophysical studies. This leads to the conclusion that 1) the cratonic lithosphere may be thinner than expected, contradicting tomographic and other geophysical or geochemical inferences, or 2) that the receiver function studies detect a mid-lithospheric discontinuity rather than the LAB. On the other hand, several recent studies documented significant changes in the direction of azimuthal anisotropy with depth that suggest layering in the anisotropic structure of the stable part of the North American continent. In particular, Yuan and Romanowicz (2010) combined long period surface wave and overtone data with core refracted shear wave (SKS) splitting measurements in a joint tomographic inversion. A question that arises is whether the anisotropic layering observed coincides with that obtained from receiver function studies. To address this question, we use a trans-dimensional Markov-chain Monte Carlo (MCMC) algorithm to generate probabilistic 1D radially and azimuthal anisotropic shear wave velocity profiles for selected stations in North America. In the algorithm we jointly invert short period (Ps Receiver Functions, surface wave dispersion for Love and Rayleigh waves) and long period data (SKS waveforms). By including three different data types, which sample different volumes of the Earth and have different sensitivities to 
structure, we overcome the problem of

  18. Effect of a short dry period on milk yield and content, colostrum quality, fertility, and metabolic status of Holstein cows.

    Science.gov (United States)

    Shoshani, E; Rozen, S; Doekes, J J

    2014-05-01

    We evaluated the effect of shortening the dry period (DP) on milk and energy-corrected milk (ECM) yields, milk components, colostrum quality, metabolic status, and reproductive parameters. Primiparous (n=372) and multiparous (n=400) Israeli Holstein cows from 5 commercial dairy herds were subjected to a 60-d or 40-d DP. Cows within each herd were paired according to milk production, age, days in milk, and expected calving. Analysis of the data from all cows, irrespective of age, revealed significant differences in milk and ECM yields that favored the 60-d DP, with a prominent effect in 2 of 5 examined herds. In primiparous cows, milk and ECM yields were similar between groups in 4 of 5 farms. In multiparous cows undergoing a 60-d (vs. 40-d) DP, milk and ECM yields were higher in 3 herds. These differences could not be explained by milk and ECM yields in cows diagnosed with metritis, ketosis, and mastitis (defined by a somatic cell count threshold of 250,000 cell/mL), distribution of infected and noninfected cows, or new infections during DP and after calving. Including the milk and ECM yields from an average of 19.55 d from the previous lactation revealed higher milk and ECM yields for 40-d (vs. 60-d) DP cows in all herds. Analyzing 2 consecutive lactations revealed similar milk and ECM yields between groups in 4 out of 5 herds. In 1 herd, yields were higher in the 40-d compared with the 60-d DP group. One week after calving, the nonesterified fatty acid concentrations of 40-d DP cows were significantly lower than those of 60-d DP cows, indicating better postpartum energy balance. Colostrum quality, measured as IgG concentration, did not differ between the 2 DP groups. Cows assigned to 40-d DP had better reproductive performance, as reflected by fewer days to first insemination, a lower proportion with >90 d to first insemination, and fewer days to pregnancy. With respect to primiparous cows, a short DP increased conception rate after first artificial insemination

  19. Improvment of short cut numerical method for determination of periods of free oscillations for basins with irregular geometry and bathymetry

    Science.gov (United States)

    Chernov, Anton; Kurkin, Andrey; Pelinovsky, Efim; Yalciner, Ahmet; Zaytsev, Andrey

    2010-05-01

    - sea - bay - harbor) phenomenons studying. The new developed software was tested for Mediterranian, Sea of Okhotsk and South China sea regions. This software can be usefull in local tsunami mapping and tsunami propagation in the coastal zone. References: Yalciner A.C., Pelinovsky E. A short cut numerical method for determination of periods of free oscillations for basins with irregular geometry and bathymetry // Ocean engineering. V. 34. 2007. С. 747 - 757

  20. The origin and evolution of short-period Miras in the solar neighborhood: Constraints on the life cycle of old stars

    Science.gov (United States)

    Jura, M.

    1994-01-01

    The spatial distribution of the short-period (P less than 300 days) oxygen-rich Miras in the solar neighborhood can be fitted with an exponential scale height above the Galactic plane of about 600 pc. Using the Gliese catalog of local main-sequence stars, we estimate that the density of suitable G-type progenitor dwarfs within 20 pc of the Sun for these short-period Miras is 6 x 10(exp -4)/cu pc. The portion of the H-R diagram near the main-sequence turnoff of these velocity-selected Gliese stars is intermediate between that of the old open cluster NGC 188 and that of the metal-rich globular cluster, 47 Tuc. We infer that the main-sequence progenitors of the short-period Miras have masses near 1.0 solar mass, and we estimate that these Miras have ages approximately 9 x 10(exp 9). We also identify a few old disk red giants in the neighborhood of the Sun. On the basis of very limited information, we estimate that the total amount of mass lost from these stars during their first ascent up the red giant branch is less than or equal to 0.1 solar mass. We derive a duration of the short-period Mira phase of close to 5 x 10(exp 5) yr. This estimate for the duration of the short period Mira phase is longer than our estimate of 2 x 10(exp 5) yr for the duration of the Mira phase for stars with periods longer than 300 days. From their infrared colors, we estimate a typical mass-loss rate from the short-period Miras of approximately 1 x 10(exp -7) solar mass/yr.

  1. Au-C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

    Science.gov (United States)

    Khan, Saif A.; Saravanan, K.; Tayyab, M.; Bagchi, S.; Avasthi, D. K.

    2016-07-01

    Structural evolution of gold-carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au-C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au-C60 NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 1018 W cm-2. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au-C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

  2. Au–C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Saif A., E-mail: khansaifahmad@gmail.com [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Saravanan, K. [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China); Tayyab, M.; Bagchi, S. [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Avasthi, D.K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Amity University, Noida 201313, Uttar Pradesh (India)

    2016-07-15

    Structural evolution of gold–carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au–C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au–C{sub 60} NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 10{sup 18} W cm{sup −2}. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au–C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

  3. Influence of winds on temporally varying short and long period gravity waves in the near shore regions of Eastern Arabian Sea

    Directory of Open Access Journals (Sweden)

    J. Glejin

    2012-09-01

    Full Text Available Wave data collected off Ratnagiri, west coast of India during 1 May 2010 to 30 April 2012 is used in the study. Seasonal and annual variation in wave data controlled by the local wind system such as sea breeze and land breeze, and remote wind generated long period waves observed along the west coast of India, is studied. Sea breeze plays an important role in determining the sea state during pre and post monsoon seasons and the maximum wave height is observed during peak hours of sea breeze at 15:00 UTC. Long period waves (peak period over 13 s are observed mainly during the pre and the post monsoon season. Maximum peak period observed during the study is 22 s and is in the month of October. Long period waves observed during the south west monsoon period of 2011 are identified as swell propagated from the Southern Ocean with an estimated travelling time of 5–6 days. The swells reaching the Arabian Sea from the South Indian Ocean and Southern Ocean, due to storms during the pre and post monsoon periods will modify the near surface winds, due to the dominant wave induced wind regime. Energy spectrum of observed waves indicates onset and decline of strong south west monsoon winds. Convergence of energy-containing frequency bands corresponding to short period waves (Tp < 8 s and long period waves (Tp > 13 s to intermediate period waves (8 < Tp < 13 s are observed at the end of the pre monsoon season; divergence is observed during the start of the post monsoon period from intermediate period waves to short period waves and long period waves. South west monsoon period is characterized by the energy corresponding to the frequency band of intermediate period waves along the west coast of India.

  4. Detection of short period intensity oscillations in the solar corona observed during the total solar eclipse of august 11, 1999

    Directory of Open Access Journals (Sweden)

    R. Rezaei

    2005-03-01

    Full Text Available   An experiment to search for short-period intensity oscillations in the solar corona was conducted during the total solar eclipse of August 11, 1999 in Esfahan, Iran. The intensity in the continuum, centered about 4700 Å and with a passband having a half-width of 190 Å, was recorded at a counting rate of 5 Hz using six low-noise Hamamatsu R647 photomultiplier tubes. We recorded intensity values from 6 different regions on the image of the solar corona from 1.2 R ° to 1.5 R ° . The power spectrum analysis of all channels, except for a channel that failed to receive any coronal light, shows excess power in the frequency range 0.02-0.2 Hz. The results of analyzing all channels demonstrate various waves with some degree of coherence and amplitudes from 0.3 to 0.7 percent of the mean coronal brightness. There are some similarities between waves in various channels and it may show that these waves exist in a large region of the corona, of the order of a few hundred thousand kilometers, much larger than the fiber optic diaphragms. The energy flux of each wave was calculated by assuming them as the slow or fast mode waves for the active and quiet regions of the solar corona. The energy flux of the fast mode waves in the active regions is comparable with the required energy flux for heating up the solar corona. The intensity oscillations observed in this experiment are similar to those detected during the 1995 and 1997 eclipses.

  5. Very short-term reactive forecasting of the solar ultraviolet index using an extreme learning machine integrated with the solar zenith angle.

    Science.gov (United States)

    Deo, Ravinesh C; Downs, Nathan; Parisi, Alfio V; Adamowski, Jan F; Quilty, John M

    2017-05-01

    Exposure to erythemally-effective solar ultraviolet radiation (UVR) that contributes to malignant keratinocyte cancers and associated health-risk is best mitigated through innovative decision-support systems, with global solar UV index (UVI) forecast necessary to inform real-time sun-protection behaviour recommendations. It follows that the UVI forecasting models are useful tools for such decision-making. In this study, a model for computationally-efficient data-driven forecasting of diffuse and global very short-term reactive (VSTR) (10-min lead-time) UVI, enhanced by drawing on the solar zenith angle (θs) data, was developed using an extreme learning machine (ELM) algorithm. An ELM algorithm typically serves to address complex and ill-defined forecasting problems. UV spectroradiometer situated in Toowoomba, Australia measured daily cycles (0500-1700h) of UVI over the austral summer period. After trialling activations functions based on sine, hard limit, logarithmic and tangent sigmoid and triangular and radial basis networks for best results, an optimal ELM architecture utilising logarithmic sigmoid equation in hidden layer, with lagged combinations of θs as the predictor data was developed. ELM's performance was evaluated using statistical metrics: correlation coefficient (r), Willmott's Index (WI), Nash-Sutcliffe efficiency coefficient (ENS), root mean square error (RMSE), and mean absolute error (MAE) between observed and forecasted UVI. Using these metrics, the ELM model's performance was compared to that of existing methods: multivariate adaptive regression spline (MARS), M5 Model Tree, and a semi-empirical (Pro6UV) clear sky model. Based on RMSE and MAE values, the ELM model (0.255, 0.346, respectively) outperformed the MARS (0.310, 0.438) and M5 Model Tree (0.346, 0.466) models. Concurring with these metrics, the Willmott's Index for the ELM, MARS and M5 Model Tree models were 0.966, 0.942 and 0.934, respectively. About 57% of the ELM model's absolute

  6. Short-Term Catheter-Directed Thrombolysis with Low-Dose Urokinase Followed by Aspiration Thrombectomy for Treatment of Symptomatic Lower Extremity Deep Venous Thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Se Hee; Lim, Nam Yeul; Song, Jang Hyeon [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Kim, Jae Kyu; Lim, Jae Hoon [Dept. of Radiology, Hospital, Ulsan University School of Medicine, Gweangju (Korea, Republic of); Chang, Nam Kyu [Dept. of Radiology, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of); Choi, Soo Jin Na; Chung, Sang Young [Dept. of Radiology, Chonnam National University Hospital, Chonnam National University School of Medicine, Gwangju (Korea, Republic of)

    2011-10-15

    To evaluate the venous patency in patients treated by catheter-directed thrombolysis with low-dose urokinase (UK) for symptomatic lower extremity deep venous thrombosis (DVT). Eighty-nine consecutive patients (46 women and 43 men; mean age, 58.1 years), treated by catheter-directed thrombolysis with low-dose UK were included in this study. Immediate venous patency was evaluated in terms of technical success (successful restoration of antegrade in-line flow in the treated vein with residual stenosis rate of less than 30%) and clinical success (significant reduction of clinical symptoms before hospital discharge). Late venous patency was evaluated in terms of primary patency rate and clinical success. Immediate technical success was achieved in all patients and immediate clinical success in 80 (90%) patients. There was no major systemic bleeding complication. The primary patency rate at 6 months and 12 months was 84% and 79%, respectively. Fifty-six (63%) patients were asymptomatic after a median clinical follow-up of 18 months, eleven (12%) patients improved moderately, seven (8%) patients remained unchanged, and fifteen (17%) patients had no clinical follow-up. Short-term catheter-directed thrombolysis with low-dose UK can be an effective, safe method to manage DVT of the lower extremities.

  7. Deep Green And Monolithic White LEDs Based On Combination Of Short-Period InGaN/GaN Superlattice And InGaN QWs

    Science.gov (United States)

    Tsatsulnikov, A. F.; Lundin, W. V.; Sakharov, A. V.; Zavarin, E. E.; Usov, S. O.; Nikolaev, A. E.; Kryzhanovskaya, N. V.; Chernyakov, A. E.; Zakgeim, A. L.; Cherkashin, N. A.; Hytch, M.

    2011-12-01

    This work presents the results of the investigation of approaches to the synthesis of the active region of LED with extended optical range. Combination of short-period InGaN/GaN superlattice and InGaN quantum well was applied to extend optical range of emission up to 560 nm. Monolithic white LED structures containing two blue and one green QWs separated by the short-period InGaN/GaN superlattice were grown with external quantum efficiency up to 5-6%.

  8. Arctic sea-ice ridges—Safe heavens for sea-ice fauna during periods of extreme ice melt?

    Science.gov (United States)

    Gradinger, Rolf; Bluhm, Bodil; Iken, Katrin

    2010-01-01

    The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate ( N=24-65 per station) 0.25 m 2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind l -1 (median 0.8 ind l -1). In level ice, low ice algal pigment concentrations (3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high-salinity water, become accumulation regions for ice meiofauna and under-ice amphipods in summer. Pressure ridges thus might be crucial for faunal survival during periods of enhanced summer ice melt. Previous estimates of Arctic sea ice meiofauna and under-ice amphipods on regional and pan-Arctic scales likely underestimate abundances at least in summer because they typically do not include pressure ridges.

  9. Short-lived increase in erosion during the African Humid Period: Evidence from the northern Kenya Rift

    Science.gov (United States)

    Garcin, Yannick; Schildgen, Taylor F.; Torres Acosta, Verónica; Melnick, Daniel; Guillemoteau, Julien; Willenbring, Jane; Strecker, Manfred R.

    2017-02-01

    The African Humid Period (AHP) between ∼15 and 5.5 cal. kyr BP caused major environmental change in East Africa, including filling of the Suguta Valley in the northern Kenya Rift with an extensive (∼2150 km2), deep (∼300 m) lake. Interfingering fluvio-lacustrine deposits of the Baragoi paleo-delta provide insights into the lake-level history and how erosion rates changed during this time, as revealed by delta-volume estimates and the concentration of cosmogenic 10Be in fluvial sand. Erosion rates derived from delta-volume estimates range from 0.019 to 0.03 mm yr-1. 10Be-derived paleo-erosion rates at ∼11.8 cal. kyr BP ranged from 0.035 to 0.086 mm yr-1, and were 2.7 to 6.6 times faster than at present. In contrast, at ∼8.7 cal. kyr BP, erosion rates were only 1.8 times faster than at present. Because 10Be-derived erosion rates integrate over several millennia, we modeled the erosion-rate history that best explains the 10Be data using established non-linear equations that describe in situ cosmogenic isotope production and decay. Two models with different temporal constraints (15-6.7 and 12-6.7 kyr) suggest erosion rates that were ∼25 to ∼300 times higher than the initial erosion rate (pre-delta formation). That pulse of high erosion rates was short (∼4 kyr or less) and must have been followed by a rapid decrease in rates while climate remained humid to reach the modern 10Be-based erosion rate of ∼0.013 mm yr-1. Our simulations also flag the two highest 10Be-derived erosion rates at ∼11.8 kyr BP related to non-uniform catchment erosion. These changes in erosion rates and processes during the AHP may reflect a strong increase in precipitation, runoff, and erosivity at the arid-to-humid transition either at ∼15 or ∼12 cal. kyr BP, before the landscape stabilized again, possibly due to increased soil production and denser vegetation.

  10. The TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b

    Science.gov (United States)

    Gillon, M.; Triaud, A. H. M. J.; Fortney, J. J.; Demory, B.-O.; Jehin, E.; Lendl, M.; Magain, P.; Kabath, P.; Queloz, D.; Alonso, R.; Anderson, D. R.; Collier Cameron, A.; Fumel, A.; Hebb, L.; Hellier, C.; Lanotte, A.; Maxted, P. F. L.; Mowlavi, N.; Smalley, B.

    2012-06-01

    We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b, in addition to eight new measurements of the radial velocity of the star. Thanks to this extensive data set, we improve significantly the parameters of the system. Notably, the largely improved precision on the stellar density (2.41 ± 0.08 ρ⊙) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper. The resulting stellar mass and size are 0.717 ± 0.025 M⊙ and 0.667 ± 0.011 R⊙. Our deduced physical parameters for the planet are 2.034 ± 0.052 MJup and 1.036 ± 0.019 RJup. Taking into account its level of irradiation, the high density of the planet favors an old age and a massive core. Our deduced orbital eccentricity, 0.0035-0.0025+0.0060, is consistent with a fully circularized orbit. We detect the emission of the planet at 2.09 μm at better than 11-σ, the deduced occultation depth being 1560 ± 140 ppm. Our detection of the occultation at 1.19 μm is marginal (790 ± 320 ppm) and more observations are needed to confirm it. We place a 3-σ upper limit of 850 ppm on the depth of the occultation at ~0.9 μm. Together, these results strongly favor a poor redistribution of the heat to the night-side of the planet, and marginally favor a model with no day-side temperature inversion. Based on data collected with the TRAPPIST and Euler telescopes at ESO La Silla Observatory, Chile, and with the VLT/HAWK-I instrument at ESO Paranal Observatory, Chile (program 086.C-0222).Tables 1 and 4 are available in electronic form at http://www.aanda.orgPhotometry is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/542/A4

  11. Increased food intake and changes in metabolic hormones in response to chronic sleep restriction alternated with short periods of sleep allowance

    NARCIS (Netherlands)

    Barf, R. Paulien; Desprez, Tifany; Meerlo, Peter; Scheurink, Anton J. W.

    2012-01-01

    Barf RP, Desprez T, Meerlo P, Scheurink AJ. Increased food intake and changes in metabolic hormones in response to chronic sleep restriction alternated with short periods of sleep allowance. Am J Physiol Regul Integr Comp Physiol 302: R112-R117, 2012. First published October 19, 2011;

  12. Increased food intake and changes in metabolic hormones in response to chronic sleep restriction alternated with short periods of sleep allowance

    NARCIS (Netherlands)

    Barf, R. Paulien; Desprez, Tifany; Meerlo, Peter; Scheurink, Anton J. W.

    2012-01-01

    Barf RP, Desprez T, Meerlo P, Scheurink AJ. Increased food intake and changes in metabolic hormones in response to chronic sleep restriction alternated with short periods of sleep allowance. Am J Physiol Regul Integr Comp Physiol 302: R112-R117, 2012. First published October 19, 2011; doi:10.1152/aj

  13. Increased food intake and changes in metabolic hormones in response to chronic sleep restriction alternated with short periods of sleep allowance

    NARCIS (Netherlands)

    Barf, R. Paulien; Desprez, Tifany; Meerlo, Peter; Scheurink, Anton J. W.

    2012-01-01

    Barf RP, Desprez T, Meerlo P, Scheurink AJ. Increased food intake and changes in metabolic hormones in response to chronic sleep restriction alternated with short periods of sleep allowance. Am J Physiol Regul Integr Comp Physiol 302: R112-R117, 2012. First published October 19, 2011; doi:10.1152/aj

  14. Extreme warming in the NE Atlantic in the winter period 2002-2012 - an analysis with the regional atmospheric model COSMO-CLM and the Arctic System Reanalysis.

    Science.gov (United States)

    Kohnemann, Svenja; Heinemann, Guenther; Gutjahr, Oliver; Bromwich, David H.

    2016-04-01

    The high-resolution atmospheric model COSMO-CLM (CCLM, German Meteorological Service) is used to simulate the 2m-temperature and the boundary layer structures in the Arctic with focus on the NE Atlantic section the winter periods (Nov-Apr) between 2002 and 2015. The CCLM simulations have a horizontal resolution of 15 km for the whole Arctic. The comparable Arctic System Reanalysis data (ASR, Byrd Polar and Climate Research Center), which has been optimized for the Arctic, are available for the same time period with a horizontal resolution of 30 km. In addition, climatological data from Automatic Weather Stations (AWS) stations are used as verification. The comparison between the CCLM simulations and the ASR data shows a high agreement. Also the verification of both data sets with AWS and Era-Interim data shows a very high correlation for the air temperature. Slight differences between CCLM and ASR are recognizable in the extreme values as CCLM has the better ice information assimilated and the higher resolution during simulations. Time series of monthly mean based 2m-temperature indicate an enormous increase for the single months for the NE Atlantic and especially the region around the Siberian Island Novaya Zemlya. For example the CCLM March increase amounts up to 16 °C for the regional maximum for the period 2002-2012. The strong increase is mainly reducible to the decreasing sea ice situation in that region during the same time.

  15. Period Cramps

    Science.gov (United States)

    ... Too Tall or Too Short All About Puberty Period Cramps KidsHealth > For Kids > Period Cramps Print A ... re a girl who gets them. What Are Period Cramps? Lots of girls experience cramps before or ...

  16. Numerical analysis of coal-gas flow and pressure relief on the mining method of extreme short-range protective strata

    Institute of Scientific and Technical Information of China (English)

    LEI Wen-jie

    2008-01-01

    The coal-gas existing condition was ameliorated in the coal seams prone to coal-gas outburst adopting the mining method of protective strata. The gas volume and the gas pressure were reduced synchronously in the protected coal seam, and the coal seam of high permeability prone to the coal-gas outburst was changed into that of low perme-ability with no proneness to the coal-gas outburst. The D15 coal seam was treated as the protective strata, and the D16-17 coal seam was treated as the protected strata in the Fifth coal mine in the Pingdingshan Coal Mining Group. The distance between the two coal seams was 5 m averagely, clarified into the extreme short-range protective strata. The numerical analysis was based on the theory of the porous media flow with the finite ele-ment method. The gas flow process and the change mechanism of the coal-gas pressure were analyzed in the process of mining the protective strata.

  17. The association between short periods of everyday life activities and affective states: a replication study using ambulatory assessment

    Directory of Open Access Journals (Sweden)

    Thomas eBossmann

    2013-04-01

    Full Text Available Regularly conducted exercise programs effectively influence affective states. Studies suggest that this is also true for short bouts of physical activity of ten minutes or less. Accordingly, everyday life activities of short duration might be used to regulate affective states. However, this association has rarely been studied in reference to unstructured activities in ongoing real-life situations. The current study examined the influence of various everyday life activities on three dimensions of mood (valence, calmness, energetic arousal in a predominantly inactive sample. Ambulatory Assessment (AA was used to investigate the association between actual physical activity (aPA and affective states during the course of one day. Seventy-seven students ages 19 - 30 participated in the study. aPA was assessed with accelerometers, and affective state assessments were conducted hourly using an e-diary with a six-item mood scale that was specially designed for AA. Multilevel analyses indicated that the mood dimensions energetic arousal (p = .001 and valence (p = .005 were positively influenced by the intensity of the activity carried out in the ten minutes prior to the assessment. As their activity increased, the participants’ positive feelings and energetic arousal increased. However, the students’ calmness was not affected by their activity levels. The findings highlight the importance of integrating short activity intervals of 10 minutes or less into everyday life routines to improve affective states.

  18. The Association between Short Periods of Everyday Life Activities and Affective States: A Replication Study Using Ambulatory Assessment.

    Science.gov (United States)

    Bossmann, Thomas; Kanning, Martina; Koudela-Hamila, Susanne; Hey, Stefan; Ebner-Priemer, Ulrich

    2013-01-01

    Regularly conducted exercise programs effectively influence affective states. Studies suggest that this is also true for short bouts of physical activity (PA) of 10 min or less. Accordingly, everyday life activities of short duration might be used to regulate affective states. However, this association has rarely been studied in reference to unstructured activities in ongoing real-life situations. The current study examined the influence of various everyday life activities on three dimensions of mood (valence, calmness, energetic arousal) in a predominantly inactive sample. Ambulatory Assessment (AA) was used to investigate the association between actual PA and affective states during the course of 1 day. Seventy-seven students ages 19-30 participated in the study. PA was assessed with accelerometers, and affective state assessments were conducted hourly using an e-diary with a six-item mood scale that was specially designed for AA. Multilevel analyses indicated that the mood dimensions energetic arousal (p = 0.001) and valence (p = 0.005) were positively influenced by the intensity of the activity carried out in the 10-min prior to the assessment. As their activity increased, the participants' positive feelings and energetic arousal increased. However, the students' calmness was not affected by their activity levels. The findings highlight the importance of integrating short activity intervals of 10 min or less into everyday life routines to improve affective states.

  19. The relative kicking frequency of infants born full-term and preterm during learning and short-term and long-term memory periods of the mobile paradigm.

    Science.gov (United States)

    Heathcock, Jill C; Bhat, Anjana N; Lobo, Michele A; Galloway, James C

    2005-01-01

    Infants born preterm differ in their spontaneous kicking, as well as their learning and memory abilities in the mobile paradigm, compared with infants born full-term. In the mobile paradigm, a supine infant's ankle is tethered to a mobile so that leg kicks cause a proportional amount of mobile movement. The purpose of this study was to investigate the relative kicking frequency of the tethered (right) and nontethered (left) legs in these 2 groups of infants. Ten infants born full-term and 10 infants born preterm (learning and short-term and long-term memory periods of the mobile paradigm. Infants born full-term showed an increase in the relative kicking frequency of the tethered leg during the learning period and the short-term memory period but not for the long-term memory period. Infants born preterm did not show a change in kicking pattern for learning or memory periods, and consistently kicked both legs in relatively equal amounts. Infants born full-term adapted their baseline kicking frequencies in a task-specific manner to move the mobile and then retained this adaptation for the short-term memory period. In contrast, infants born preterm showed no adaptation, suggesting a lack of purposeful leg control. This lack of control may reflect a general decrease in the ability of infants born preterm to use their limb movements to interact with their environment. As such, the mobile paradigm may be clinically useful in the early assessment and intervention of infants born preterm and at risk for future impairment.

  20. Band gap tuning and optical absorption in type-II InAs/GaSb mid infrared short period superlattices: 14 bands Kṡp study

    Science.gov (United States)

    AbuEl-Rub, Khaled M.

    2012-09-01

    The MBE growth of short-period InAs/GaSb type-II superlattice structures, varied around 20.5 Å InAs/24 Å GaSb were [J. Applied physics, 96, 2580 (2004)] carried out by Haugan et al. These SLs were designed to produce devices with an optimum mid-infrared photoresponse and a sharpest photoresponse cutoff. We have used a realistic and reliable 14-band k.p formalism description of the superlattice electronic band structure to calculate the absorption coefficient in such short-period InAs/GaSb type-II superlattices. The parameters for this formalism are known from fitting to independent experiments for the bulk materials. The band-gap energies are obtained without any fitting parameters, and are in good agreement with experimental data.

  1. Band gap tuning and optical absorption in type-II InAs/GaSb mid infrared short period superlattices: 14 bands K Dot-Operator p study

    Energy Technology Data Exchange (ETDEWEB)

    AbuEl-Rub, Khaled M. [Department of Applied Physical Sciences, Jordan University of Science and Technology Irbid, 21141 (Jordan)

    2012-09-06

    The MBE growth of short-period InAs/GaSb type-II superlattice structures, varied around 20.5 A InAs/24 A GaSb were [J. Applied physics, 96, 2580 (2004)] carried out by Haugan et al. These SLs were designed to produce devices with an optimum mid-infrared photoresponse and a sharpest photoresponse cutoff. We have used a realistic and reliable 14-band k.p formalism description of the superlattice electronic band structure to calculate the absorption coefficient in such short-period InAs/GaSb type-II superlattices. The parameters for this formalism are known from fitting to independent experiments for the bulk materials. The band-gap energies are obtained without any fitting parameters, and are in good agreement with experimental data.

  2. Structural evidence for enhanced polarization in a commensurate short-period BaTiO3/SrTiO3 superlattice

    Science.gov (United States)

    Tian, W.; Jiang, J. C.; Pan, X. Q.; Haeni, J. H.; Li, Y. L.; Chen, L. Q.; Schlom, D. G.; Neaton, J. B.; Rabe, K. M.; Jia, Q. X.

    2006-08-01

    A short-period (BaTiO3)6/(SrTiO3)5 superlattice was characterized by x-ray diffraction and transmission electron microscopy. The superlattice is epitaxially oriented with the c axes of BaTiO3 and SrTiO3 normal to the (001) surface of the SrTiO3 substrate. Despite the large in-plane lattice mismatch between BaTiO3 and SrTiO3 (˜2.2%), the superlattice interfaces were found to be nearly commensurate. The crystallographic c /a ratio of the superlattice was measured and the results agree quantitatively with first-principles calculations and phase-field modeling. The agreement supports the validity of the enhanced spontaneous polarization predicted for short-period BaTiO3/SrTiO3 superlattices.

  3. The mass and radius of the M-dwarf in the short-period eclipsing binary RR Caeli

    NARCIS (Netherlands)

    Maxted, P.F.L.; O'Donoghue, D.; Morales-Rueda, L.; Napiwotzki, R.; Smalley, B.

    2007-01-01

    We present new photometry and spectroscopy of the eclipsing white dwarf-M-dwarf binary star RR Cae. We use timings of the primary eclipse from white-light photo-electric photometry to derive a new ephemeris for the eclipses. We find no evidence for any period change greater than over a time-scale of

  4. Quasi-periodic Oscillations in Short Recurring Bursts of the Soft Gamma Repeater J1550-5418

    NARCIS (Netherlands)

    D. Huppenkothen; C. D'Angelo; A.L. Watts; L.M. Heil; M. van der Klis; A.J. van der Horst; C. Kouveliotou; M.G. Baring; E. Gögüs; J. Granot; Y. Kaneko; L. Lin; A. von Kienlin; G. Younes

    2014-01-01

    The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. The scarcity of giant flares makes a search for QPOs in the shorter, far more numerous bursts from soft gamma repeaters (SGRs) desirable. In Huppenkothen et al., we

  5. Ultra-short-pulsed laser-machined nanogratings of laser-induced periodic surface structures on thin molybdenum layers

    NARCIS (Netherlands)

    Scorticati, D.; Römer, G.W.; Lange, D.F. de; Huis In 't Veld, B.

    2012-01-01

    Large areas of regular diffraction nanogratings were produced consisting of so-called laser-induced periodic surface structures (LIPSS) on thin molybdenum layers (<400 nm) deposited on a borosilicate glass substrate. The aim was to produce these structures without ablating nor cracking the molybdenu

  6. Trend analysis of surface downward short and longwave radiation at four sites in Switzerland: Update for the 1996 - 2016 period

    Science.gov (United States)

    Nyeki, Stephan; Gröbner, Julian; Aebi, Christine; Wacker, Stefan; Vuilleumier, Laurent; Martucci, Giovanni

    2017-04-01

    We present an updated trend analysis of downward short and longwave radiation (DSR, DLR) and aerosol optical depth (AOD) at four stations of the MeteoSwiss SACRaM (Swiss Alpine Climate Radiation Monitoring) network in Switzerland. The stations cover an altitude range between 370 and 3580 meters above sea level, and include Locarno, Payerne, Davos and Jungfraujoch. In a previous study, Wacker et al. (AIP Proc., 2013) observed positive trends for 1996 - 2010 in DSR but only Locarno was significant at the 95% confidence level. DLR trends remained flat. In addition, the net cloud radiative effect was found to decrease by up to 7.5 W m-2 , implying a reduction in fractional cloud cover. While the trend in AOD at the SACRaM stations was found to be negative for 1995 - 2005 (Ruckstuhl et al., JGR, 2008), a later study for the Davos and Jungfraujoch high-alpine stations for 1995 - 2010 (Nyeki et al., JGR, 2012) found no significant trends. In the present study, we will present updated and homogenised time-series of DSR, DLR, and AOD with respect to all-sky and clear-sky conditions for 1996 - 2016. Short and longwave clear-sky models will be used to explain and quantify the causes for any observed trends.

  7. Investigating of short period gravity waves using multi-beam experiments above Andenes in the polar summer mesopause

    Science.gov (United States)

    Stober, Gunter; Sommer, Svenja; Chau, Jorge L.; Latteck, Ralph

    2014-05-01

    In summer 2013 the Middle Atmosphere Alomar Radar System (MAARSY) conducted a multi-beam scanning experiment using 65 different beam directions. These systematic scanning experiments are analysed with respect to gravity waves with periods from 4 minutes up to 8 hours using polar mesospheric summer echoes (PMSE) as tracer. The gravity waves are investigated by decomposing the wind field into a mean wind and superimposed tidal components (diurnal, semidiurnal and terdiurnal). After subtracting these mean winds and tides we get a residuum wind dominated by the gravity waves with periods shorter than 8 hours. Using this approach we have been able to identified significant wave burst, with amplitudes as high as 50 m/s and 10-20 m/s for the horizontal and vertical wind components, respectively. In addition, we have identified events that indicate the development of KH-instabilities.

  8. Plasmodesmatal Dynamics in Both Woody Poplar and Herbaceous Winter Wheat Under Controlled Short Day and in Field Winter Period

    Institute of Scientific and Technical Information of China (English)

    JIANLing-Cheng; WANGHong

    2004-01-01

    Electron microscopic observation revealed that poplar (Populus deltoides Marsh.) and winterwheat ( Triticum aestivum L. cv. Seward 80004) plasmodesmatal structures significantly changed undershort day (SD, 8 h light) and in winter period, and such changes differed also noticeably between these twowoody and herbaceous plants. Under long day (LD, 16 h light), many plasmodesmata with strong stainappeared in the cell wall of both poplar apical buds and winter wheat young leaf tissues, and connections ofcytoplasmic endoplasmic reticulum (ER) with the ER in some plasmodesmata were observed. In addition,the typical “neck type” plasmodesmata were observed in winter wheat young leaf tissues, and their centraldesmotubules (appressed-ER) could be clearly identified. Under SD, many poplar plasmodesmata showedonly a partial structure in the cell wall and appeared to be discontinued; some plasmodesmata swelled in themid-wall, forming the cavity, and no appressed-ER appeared, in winter wheat, however, no noticeablealterations of plasmodesmata occurred, and the plasmodesmatal structure essentially remained the sameas it was under LD. In winter period, poplar plasmodesmata had a similar morphology as those observedunder SD, however, winter wheat manifested at least two types of significant plasmodesmatal alterations:one plugged by electron-dense materials and the other of reduced neck region compared to those underLD. The above dynamic difference of the two species plasmodesmata under SD and winter period revealedthe difference of their dormancy development under those environmental conditions.

  9. Observations and modeling of the companions of short period binary millisecond pulsars: evidence for high-mass neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Joshua; Halpern, Jules [Department of Astronomy, Columbia University, Mail Code 5246, 550 West 120th Street, New York, NY 10027 (United States)

    2014-10-01

    We present observations of fields containing eight recently discovered binary millisecond pulsars using the telescopes at MDM Observatory. Optical counterparts to four of these systems are detected, one of which, PSR J2214+3000, is a novel detection. Additionally, we present the fully phase-resolved B, V, and R light curves of the optical counterparts to two objects, PSR J1810+1744 and PSR J2215+5135 for which we employ model fitting using the eclipsing light curve (ELC) model of Orosz and Hauschildt to measure the unknown system parameters. For PSR J1810+1744, we find that the system parameters cannot be fit even assuming that 100% of the spin-down luminosity of the pulsar is irradiating the secondary, and so radial velocity measurements of this object will be required for the complete solution. However, PSR J2215+5135 exhibits light curves that are extremely well constrained using the ELC model and we find that the mass of the neutron star is constrained by these and the radio observations to be M {sub NS} > 1.75 M {sub ☉} at the 3σ level. We also find a discrepancy between the model temperature and the measured colors of this object, which we interpret as possible evidence for an additional high-temperature source such as a quiescent disk. Given this and the fact that PSR J2215+5135 contains a relatively high mass companion (M {sub c} > 0.1 M {sub ☉}), we propose that similar to the binary pulsar systems PSR J1023+0038 and IGR J18245–2452, the pulsar may transition between accretion- and rotation-powered modes.

  10. [Bibliographic consideration of proper management of radioactive waste on short-lived period nuclides that are used in nuclear medicine].

    Science.gov (United States)

    Kida, Tetsuo; Watanabe, Hiroshi; Yamaguchi, Ichirou; Nagaoka, Hiroaki; Fujibuchi, Toshioh; Tanaka, Shinji; Hayakawa, Toshio

    2009-05-20

    A rational clearance system for medical radioactive waste has not yet been established in Japan. As Europe and USA's ways, the establishment of DIS that medical radioactive waste what are kept in storage room for more than decided period each nuclide except from regulation of radiation's control. The purpose of this report is to clarify the problems with the establishment of DIS in Japan through a literature review of the experience in Europe and the USA and previous research that has been reported in Japan. To establish the DIS system, the radiation control system in nuclear medicine should be rebuilt and put into effect.

  11. Short communication: Maternal heat stress during the dry period alters postnatal whole-body insulin response of calves.

    Science.gov (United States)

    Tao, S; Monteiro, A P A; Hayen, M J; Dahl, G E

    2014-02-01

    Heat stress during the dry period not only negatively affects a cow's performance but also affects her offspring. Previous studies indicate that calves born to cows heat-stressed during late gestation have lower birth weight but similar overall weight gain during the prepubertal period compared with those cooled in utero. However, it is unclear if whole-body insulin response, and thus metabolism, of calves is altered in their postnatal life after in utero heat stress. The aim of the present study was to examine the effects of maternal heat stress during the dry period on whole-body insulin response of calves after weaning. Calves (10/treatment) were born to cows exposed to heat stress (HT) or cooling (CL) when dry. Calves were immediately separated from their dams and fed 3.8L of high-quality colostrum within 1h after birth and then 1.9L 12h later. All calves were fed 1.9 to 3.8L of pasteurized milk in the morning and afternoon from 2 to 42 d of age and then only in the morning until weaning at 49 d. Calf starter and water were offered ad libitum starting at 2 d of age. All calves were managed in the same manner throughout the study. All calves were subjected to a glucose tolerance test (GTT) and an insulin challenge (IC) at 55 d of age. Calves heat-stressed in utero were born lighter (40 ± 1.4 vs. 45 ± 1.4 kg) compared with CL calves. Both groups of calves had similar weaning weights (HT: 68 ± 3.2 kg; CL: 71 ± 3.3 kg) and body weight gain from birth to weaning (HT: 28 ± 2.2 kg; CL: 26 ± 2.3 kg). Compared with those cooled in utero, HT calves had a similar insulin response to GTT and insulin clearance during IC but faster glucose clearance during GTT and IC. In conclusion, in addition to impaired fetal growth, maternal heat stress during the dry period enhances the whole-body insulin response of calves after weaning, which suggests the possibility of accelerated lipogenesis and fat deposition in early life.

  12. Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e

    CERN Document Server

    Dawson, Rebekah I

    2010-01-01

    Radial velocity measurements of stellar reflex motion have revealed many extra-solar planets, but gaps in the observations produce aliases, spurious frequencies that are frequently confused with the planets' orbital frequencies. In the case of Gl 581d, the distinction between an alias and the true frequency was the distinction between a dead, frozen planet and a planet likely hospitable to life (Udry et al. 2007; Mayor et al. 2009). To improve the characterization of planetary systems, we describe how aliases originate and present a new approach for distinguishing between orbital frequencies and their aliases. Our approach harnesses features in the spectral window function to compare the amplitude and phase of predicted aliases with peaks present in the data. We apply it to confirm prior alias distinctions for the planets GJ 876d and HD 75898b. We find that the true periods of Gl 581c and HD 73526b/c remain ambiguous. We revise the periods of HD 156668b and 55 Cnc e, which were afflicted by daily aliases. For...

  13. Short-Term Outcomes of 100 Consecutive Kidney Transplantations in a 3-Year Period: A Single-Center Experience.

    Science.gov (United States)

    Alfaro Sanchez, C I; Molina Higueras, M J; Moiron Fernandez-Felechosa, J P; Mora Gutierrez, J M; Martin Moreno, P L; Garcia Fernandez, N; Lavilla Royo, F J; Errasti Goenaga, P

    2016-11-01

    The results of kidney transplantation have improved significantly in the last decade with patient and graft survival rates that range from 92% to 95%. We analyzed the clinical results in the last 100 consecutive patients with a follow-up of 6-42 months at our institution. We also made a general evaluation of the patients before surgery as candidates for transplantation and divided them into 3 groups (good, moderate, and poor). We had 8 living donors and 92 cadaveric kidney transplantation cases. Principal cause of donor death was cerebrovascular disease accounting for 64%. Mean age of recipients was 55.1 ± 12.9 years with a total of 65 males. Currently there are 96 functioning allografts. During this 3-year period, 2 patients suffered graft loss and 2 patients died with a functioning allograft. We studied whether there were statistically significant differences in renal function (Modification of Diet in Renal Disease Study Equation [MDRD]) at 12 months and at last visit with respect to the evaluation of recipient as candidate for renal transplantation. Our observations suggest great improvement of early results of renal transplantation in recent years, including complex cases. In this 3-year period we had a patient survival rate of 98% and a graft survival rate of 96% of cases. Further dedicated prospective studies that aim to evaluate or to propose possible recipient-related predictors for kidney transplantation outcomes in different populations are needed. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearest block bootstrap approach

    Institute of Scientific and Technical Information of China (English)

    CHAN Kung-Sik; TONG Howell; STENSETH Nils Chr

    2009-01-01

    The study of the rodent fluctuations of the North was initiated in its modern form with Elton's pioneering work. Many scientific studies have been designed to collect yearly rodent abundance data, but the resulting time series are generally subject to at least two "problems": being short and non-linear. We explore the use of the continuous threshold autoregressive (TAR) models for analyzing such data. In the simplest case, the continuous TAR models are additive autoregressive models, being piecewise linear in one lag, and linear in all other lags. The location of the slope change is called the threshold parameter. The continuous TAR models for rodent abundance data can be derived from a general prey-predator model under some simplifying assumptions. The lag in which the threshold is located sheds important insights on the structure of the prey-predator system. We propose to assess the uncertainty on the location of the threshold via a new bootstrap called the nearest block bootstrap (NBB) which combines the methods of moving block bootstrap and the nearest neighbor bootstrap.The NBB assumes an underlying finite-order time-homogeneous Markov process. Essentially, the NBB bootstraps blocks of random block sizes, with each block being drawn from a non-parametric estimate of the future distribution given the realized past bootstrap series. We illustrate the methods by simulations and on a particular rodent abundance time series from Kilpisjarvi, Northern Finland.

  15. Task-irrelevant distractors in the delay period interfere selectively with visual short-term memory for spatial locations.

    Science.gov (United States)

    Marini, Francesco; Scott, Jerry; Aron, Adam R; Ester, Edward F

    2017-07-01

    Visual short-term memory (VSTM) enables the representation of information in a readily accessible state. VSTM is typically conceptualized as a form of "active" storage that is resistant to interference or disruption, yet several recent studies have shown that under some circumstances task-irrelevant distractors may indeed disrupt performance. Here, we investigated how task-irrelevant visual distractors affected VSTM by asking whether distractors induce a general loss of remembered information or selectively interfere with memory representations. In a VSTM task, participants recalled the spatial location of a target visual stimulus after a delay in which distractors were presented on 75% of trials. Notably, the distractor's eccentricity always matched the eccentricity of the target, while in the critical conditions the distractor's angular position was shifted either clockwise or counterclockwise relative to the target. We then computed estimates of recall error for both eccentricity and polar angle. A general interference model would predict an effect of distractors on both polar angle and eccentricity errors, while a selective interference model would predict effects of distractors on angle but not on eccentricity errors. Results showed that for stimulus angle there was an increase in the magnitude and variability of recall errors. However, distractors had no effect on estimates of stimulus eccentricity. Our results suggest that distractors selectively interfere with VSTM for spatial locations.

  16. A statistical analysis of energy and power demand for the tractive purposes of an electric vehicle in urban traffic - an analysis of a short and long observation period

    Science.gov (United States)

    Slaski, G.; Ohde, B.

    2016-09-01

    The article presents the results of a statistical dispersion analysis of an energy and power demand for tractive purposes of a battery electric vehicle. The authors compare data distribution for different values of an average speed in two approaches, namely a short and long period of observation. The short period of observation (generally around several hundred meters) results from a previously proposed macroscopic energy consumption model based on an average speed per road section. This approach yielded high values of standard deviation and coefficient of variation (the ratio between standard deviation and the mean) around 0.7-1.2. The long period of observation (about several kilometers long) is similar in length to standardized speed cycles used in testing a vehicle energy consumption and available range. The data were analysed to determine the impact of observation length on the energy and power demand variation. The analysis was based on a simulation of electric power and energy consumption performed with speed profiles data recorded in Poznan agglomeration.

  17. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study

    Directory of Open Access Journals (Sweden)

    Alberto Lázaro

    2016-01-01

    Full Text Available Warm ischemia (WI produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis, and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only.

  18. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study.

    Science.gov (United States)

    Lázaro, Alberto; Humanes, Blanca; Jado, Juan Carlos; Mojena, Marina; González-Nicolás, María Ángeles; Del Cañizo, Juan Francisco; Tejedor, Alberto; Lledó-García, Enrique

    2016-01-01

    Warm ischemia (WI) produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP) seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis), and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only.

  19. Short periods of prenatal stress affect growth, behaviour and hypothalamo-pituitary-adrenal axis activity in male guinea pig offspring.

    Science.gov (United States)

    Kapoor, Amita; Matthews, Stephen G

    2005-08-01

    Prenatal stress can have profound long-term influences on physiological function throughout the course of life. We hypothesized that focused periods of moderate prenatal stress at discrete time points in late gestation have differential effects on hypothalamo-pituitary-adrenal (HPA) axis function in adult guinea pig offspring, and that changes in HPA axis function will be associated with modification of anxiety-related behaviour. Pregnant guinea pigs were exposed to a strobe light for 2 h on gestational days (GD) 50, 51, 52 (PS50) or 60, 61, 62 (PS60) (gestation length approximately 70 days). A control group was left undisturbed throughout pregnancy. Behaviour was assessed in male offspring on postnatal day (PND)25 and PND70 by measurement of ambulatory activity and thigmotaxis (wall-seeking behaviour) in a novel open field environment. Subsequent to behavioural testing, male offspring were cannulated (PND75) to evaluate basal and activated HPA axis function. Body weight was significantly decreased in adult PS50 and PS60 offspring and this effect was apparent soon after weaning. The brain-to-body-weight ratio was significantly increased in adult PS50 males. Basal plasma cortisol levels were elevated in PS50 male offspring throughout the 24 h sampling period compared with controls. In response to an ACTH challenge and to exposure to an acute stressor, PS60 male offspring exhibited elevated plasma cortisol responses. Plasma testosterone concentrations were strikingly decreased in PS50 offspring. Thigmotaxis in the novel environment was increased in PS50 male offspring at PND25 and PND70, suggesting increased anxiety in these animals. In conclusion, prenatal stress during critical windows of neuroendocrine development programs growth, HPA axis function, and stress-related behaviour in adult male guinea pig offspring. Further, the nature of the effect is dependant on the timing of the maternal stress during pregnancy.

  20. Analyzing short time series data from periodically fluctuating rodent populations by threshold models:A nearest block bootstrap approach

    Institute of Scientific and Technical Information of China (English)

    CHAN; Kung-Sik; TONG; Howell; STENSETH; Nils; Chr

    2009-01-01

    The study of the rodent fluctuations of the North was initiated in its modern form with Elton’s pioneering work.Many scientific studies have been designed to collect yearly rodent abundance data,but the resulting time series are generally subject to at least two "problems":being short and non-linear.We explore the use of the continuous threshold autoregressive(TAR) models for analyzing such data.In the simplest case,the continuous TAR models are additive autoregressive models,being piecewise linear in one lag,and linear in all other lags.The location of the slope change is called the threshold parameter.The continuous TAR models for rodent abundance data can be derived from a general prey-predator model under some simplifying assumptions.The lag in which the threshold is located sheds important insights on the structure of the prey-predator system.We propose to assess the uncertainty on the location of the threshold via a new bootstrap called the nearest block bootstrap(NBB) which combines the methods of moving block bootstrap and the nearest neighbor bootstrap.The NBB assumes an underlying finite-order time-homogeneous Markov process.Essentially,the NBB bootstraps blocks of random block sizes,with each block being drawn from a non-parametric estimate of the future distribution given the realized past bootstrap series.We illustrate the methods by simulations and on a particular rodent abundance time series from Kilpisjrvi,Northern Finland.

  1. Assessing and modeling sediment mobility in estuarine and coastal settings due to extreme climate events from natural short-lived isotope distribution

    Science.gov (United States)

    Ghaleb, Bassam; Hillaire-Marcel, Claude; Ruiz Fernandez, Ana-Carolina; Sanchez Cabeza, Joan-Albert

    2016-04-01

    Climatic events (e.g. floods, storminess) and management activities (e.g. dredging) may result in the burial or removal and re-suspension of sediments in estuaries and coastal areas. When such sediments are contaminated, such processes may either help restoring better chemical environments or lead to their long-term contamination. Geochemical signatures in surface sediments may help identifying such sedimentological events. However, short-lived isotope data are generally required to set time-constraints on their occurrence. Whereas 210Pb and radioactive fallout isotope contents can help setting time constraints at ~50 to ~100 yr-time scales, natural disequilibria in the 232Th-228Ra-228Th sequence do provide information on processes which occurred within the last 30 yrs, as illustrated in the present study. Box-cored sediments from the Saguenay Fjord and lower estuary of the St. Lawrence (Canada) as well as from estuaries and lagoons from the Sinaloa Coast (Mexico) are used to document the behavior of these isotopes either under relatively steady conditions (St. Lawrence estuary) or under high-frequency extreme climate events (storms and floods; Saguenay Fjord, Coastal Sinaloa). 228Th/232Th activity ratios were determined by chemical extraction of Th and alpha counting of unspiked samples, rapidly after sampling (228Th/232Th). The activity of the intermediate isotope 228Ra was then estimated based on replicate measurements on aliquot samples made a few years later. Under steady conditions, core-top sediment shows an excess in 228Th vs 232Th (AR ~ 1.6), whereas the intermediate 228Ra depicts a deficit vs its parent 232Th (AR ~0.6). Downcore, radioactive decay carries rapidly 228Th-activities to those of the parent 228Ra within about 10 yrs (i.e., ~ 5 half-lives of 228Th), then both move during the next ~20 yrs (~ i.e., ~ 5 half-lives of 228Ra, when added to the 10 yrs of 228Th-excess) towards secular equilibrium with the parent long-lived 232Th. A few algorithms

  2. Effect of microscopic interface asymmetry on optical properties of short-period InAs/GaSb type-II superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Dong, H.M. [Department of Physics, China University of Mining and Technology, Xuzhou 221116 (China); Li, L.L., E-mail: lllihfcas@foxmail.com [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Xu, W. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics, Yunnan University, Kunming 650091 (China); Han, K. [Department of Physics, China University of Mining and Technology, Xuzhou 221116 (China)

    2015-08-31

    We theoretically investigate the effect of microscopic interface asymmetry (MIA) on the optical properties of short-period InAs/GaSb type-II superlattices (SLs) which can serve for the mid-infrared (mid-IR) detection. To calculate the band structures of such SLs, we use a modified eight-band Kane model which includes the MIA effect. With the band structures, we can evaluate the optical matrix elements and joint density of states for the corresponding SL systems. Based on these obtained results, we employ the Boltzmann equation approach to calculate the optical absorption coefficients for the corresponding SL systems. Theoretical calculations demonstrate that the MIA effect can greatly influence the electronic and optical properties of short-period InAs/GaSb type-II SLs. For the band structures, we find that the MIA effect causes strong interactions between different SL subbands and creates large spin splittings of these subbands. For the optical properties, the MIA effect activates the forbidden optical transition channels for TM polarization, enhances the absorption strength considerably and induces remarkable red-shifts for both transverse electric (TE) and transverse magnetic (TM) polarizations, where TE and TM refer to light polarizations along the in-plane and growth directions of SL structure. Different absorption features for TE and TM polarizations are well manifested by corresponding optical matrix elements. Moreover, in conjunction with recent experiment, we calculate the polarization-dependent absorption spectra for mid-IR InAs/GaSb type-II SLs. Our theoretical results can explain those observed experimentally. The present work sheds the significant importance of MIA effect in short-period InAs/GaSb type-II SLs. - Highlights: • Optical properties of InAs/GaSb superlattices (SLs) are studied theoretically. • The microscopic interface asymmetry (MIA) effect is considered for such SLs. • The MIA effect influences the optical properties of such SLs

  3. A 420 day X-ray/optical modulation and extended X-ray dips in the short-period transient Swift J1753.5-0127

    CERN Document Server

    Shaw, A W; Bird, A J; Cornelisse, R; Casares, J; Lewis, F; Muñoz-Darias, T; Russell, D M; Zurita, C

    2013-01-01

    We have discovered a \\sim420d modulation, with associated X-ray dips, in RXTE-ASM/MAXI/Swift-BAT archival light-curves of the short-period (3.2h) black-hole X-ray transient, Swift J1753.5-0127. This modulation only appeared at the end of a gradual rebrightening, approximately 3 years after the initial X-ray outburst in mid-2005. The same periodicity is present in both the 2-20 keV and 15-50 keV bands, but with a \\sim0.1 phase offset (\\sim40d). Contemporaneous photometry in the optical and near-IR reveals a weaker modulation, but consistent with the X-ray period. There are two substantial X-ray dips (very strong in the 15-50 keV band, weaker at lower energies) that are separated by an interval equal to the X-ray period. This likely indicates two physically separated emitting regions for the hard X-ray and lower energy emission. We interpret this periodicity as a property of the accretion disc, most likely a long-term precession, where the disc edge structure and X-ray irradiation is responsible for the hard X-...

  4. Northern Wabash Valley Seismic Zone and the La Salle anticline seismicity determined by a short period phased array

    Science.gov (United States)

    Brazitis, Daniel

    The Wabash Valley Seismic Zone (WVSZ) has produced three moderate sized earthquakes greater than or equal to mb 5.0 in the past 50 years. The majority of Wabash Valley faults originate near the junction of the Rough Creek and Cottage Grove faults and extend northeastward along the Wabash River. These faults extend through the Paleozoic and into the Precambrian and are believe to be associated with the Reelfoot Rift. Two of these moderate sized earthquakes have occurred north of the terminus of the Wabash Valley faults that the WVSZ is commonly associated with. This suggests that other sources of seismicity exist. The La Salle anticline, a Precambrian basement feature, is oriented NW to SE just north of the termination of these faults. The La Salle anticline creates up to a 750 meter uplift in the above Paleozoic strata. This uplift creates faults within the Paleozoic strata and within the La Salle anticline. This study uses seismometers arranged in a phased array near the southern terminus of the La Salle anticline to analyze the seismicity of the region. Analyzing the seismicity of the region over a 6-month period found 834 events. The vast majority were determined to be mine blasts or otherwise human induced. Two small earthquakes ( M 1.0) located near the La Salle anticline. These earthquakes likely occur on faults associated with the anticline. The lack of earthquakes suggested the b-value of the La Salle region could be as low as 0.56. This is lower than the typical value of 1, but consistent with other intraplate regions and previous studies of the WVSZ finding values nearer 0.7.

  5. Spectroscopic orbits of two short-period early-type binaries using two-dimensional cross-correlations

    Science.gov (United States)

    González, J. F.; Lapasset, E.

    2003-06-01

    We apply the two-dimensional cross-correlation technique TODCOR to derive spectroscopic orbits for the two B-type double-lined spectroscopic binaries HD 66066A and HD 315031, previously mentioned as blue straggler candidates of the open clusters NGC 2516 and NGC 6530, respectively. Reliable radial velocities for both components are measured even for orbital phases for which the separation between the spectral lines are about 0.5 times the quadratic sum of the full-width at half-maximum of the lines. Both binaries have circular orbits and the orbital periods are 1.67 and 1.38 days for HD 66066A and HD 315031, respectively. We calculate minimum masses with errors of 3-5% and obtain the projected radii from the line widths. We derive absolute stellar parameters which are consistent with the age and distance of the clusters. Both binary systems are formed by main-sequence stars and it is expected that they will experience mass-transfer between their components before the end of the core H-burning stage. HD 315031 is likely a triple system as suggested by the variation of the center-of-mass velocity. The observations presented here were obtained at the Complejo Astronómico El Leoncito (CASLEO), which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina (CONICET) and the National Universities of La Plata, Córdoba and San Juan.

  6. Layered structure in the upper mantle across North America from joint inversion of long and short period seismic data

    Science.gov (United States)

    Calò, M.; Bodin, T.; Romanowicz, B.

    2016-09-01

    We estimate crustal and uppermost mantle shear velocity structure beneath 30 stations in North America by jointly inverting the high frequency scattered wavefield observed in the P wave coda, together with long period surface wave phase and group dispersion data. Several features distinguish our approach from previous such joint inversions. 1) We apply a cross-convolution method, rather than more standard deconvolution approaches used in receiver function studies, and consider both Love and Rayleigh wave dispersion, allowing us to infer profiles of radial anisotropy. 2) We generate probabilistic 1D radially anisotropic depth profiles across the whole uppermost mantle, down to ∼350 km depth. 3) The inverse problem is cast in a trans-dimensional Bayesian formalism, where the number of isotropic and anisotropic layers is treated as unknown, allowing us to obtain models described with the least number of parameters. Results show that the tectonically active region west of the Rocky Mountain Front is marked by a Lithospheric Asthenosphere Boundary and a Lehmann Discontinuity occurring at relatively shallow depths (60-150 km and 100-200 km, respectively), whereas further east, in the stable craton, these discontinuities are deeper (170-200 km and 200-250 km, respectively). In addition, in the stable part of the continent, at least two Mid-Lithospheric Discontinuities are present at intermediate depths, suggesting the existence of strong lithospheric layering, and a mechanism for lithospheric thickening by underplating of additional layers as cratonic age increases. The Moho across the continent as well as mid-crustal discontinuities in the craton are also imaged, in agreement with independent studies.

  7. How extreme are extremes?

    Science.gov (United States)

    Cucchi, Marco; Petitta, Marcello; Calmanti, Sandro

    2016-04-01

    High temperatures have an impact on the energy balance of any living organism and on the operational capabilities of critical infrastructures. Heat-wave indicators have been mainly developed with the aim of capturing the potential impacts on specific sectors (agriculture, health, wildfires, transport, power generation and distribution). However, the ability to capture the occurrence of extreme temperature events is an essential property of a multi-hazard extreme climate indicator. Aim of this study is to develop a standardized heat-wave indicator, that can be combined with other indices in order to describe multiple hazards in a single indicator. The proposed approach can be used in order to have a quantified indicator of the strenght of a certain extreme. As a matter of fact, extremes are usually distributed in exponential or exponential-exponential functions and it is difficult to quickly asses how strong was an extreme events considering only its magnitude. The proposed approach simplify the quantitative and qualitative communication of extreme magnitude

  8. Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery

    Institute of Scientific and Technical Information of China (English)

    Zhang Gang; Jaana Luoranen; Heikki Smolander

    2007-01-01

    In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus,frost hardening is usually delayed. To solve this problem, We used a three-week period of short-day (SD) treatment between late July and mid-August. During autumn after frost exposure,frost hardiness (FH) Was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore,the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.

  9. The upper and middle crustal velocity structure of the northern part of Hebei plain inferred from short period surface wave dispersion

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on short period Rayleigh wave data recorded by Beijing Seismic Telemetered Network, the dispersion curves of Raleigh wave phase velocity, with period from 2 s to 18 s, are calculated by means of two-station method, for 5 paths across the earthquake zone located in the Beijing graben and the Hebei plain. According to the dispersion features, the upper and middle crustal S wave velocity structures are respectively obtained for the northern segment of Beijing graben and the northern part of Hebei plain. The results show that there is an obvious interface at the depth of 9 km in the Beijing graben, the velocity varies little with depth in the middle crust, and there is a low-velocity-zone, with a thickness of 5 km and a buried depth of 14.6 km, in the middle crust of the Hebei plain.

  10. K2-111 b - a short period super-Earth transiting a metal poor, evolved old star

    Science.gov (United States)

    Fridlund, Malcolm; Gaidos, Eric; Barragán, Oscar; Persson, Carina M.; Gandolfi, Davide; Cabrera, Juan; Hirano, Teruyuki; Kuzuhara, Masayuki; Csizmadia, Sz.; Nowak, Grzegorz; Endl, Michael; Grziwa, Sascha; Korth, Judith; Pfaff, Jeremias; Bitsch, Bertram; Johansen, Anders; Mustill, Alexander J.; Davies, Melvyn B.; Deeg, Hans J.; Palle, Enric; Cochran, William D.; Eigmüller, Philipp; Erikson, Anders; Guenther, Eike; Hatzes, Artie P.; Kiilerich, Amanda; Kudo, Tomoyuki; MacQueen, Phillip; Narita, Norio; Nespral, David; Pätzold, Martin; Prieto-Arranz, Jorge; Rauer, Heike; Van Eylen, Vincent

    2017-07-01

    Context. From a light curve acquired through the K2 space mission, the star K2-111(EPIC 210894022) has been identified as possibly orbited by a transiting planet. Aims: Our aim is to confirm the planetary nature of the object and derive its fundamental parameters. Methods: We analyse the light curve variations during the planetary transit using packages developed specifically for exoplanetary transits. Reconnaissance spectroscopy and radial velocity observations have been obtained using three separate telescope and spectrograph combinations. The spectroscopic synthesis package SME has been used to derive the stellar photospheric parameters that were used as input to various stellar evolutionary tracks in order to derive the parameters of the system. The planetary transit was also validated to occur on the assumed host star through adaptive imaging and statistical analysis. Results: The star is found to be located in the background of the Hyades cluster at a distance at least 4 times further away from Earth than the cluster itself. The spectrum and the space velocities of K2-111 strongly suggest it to be a member of the thick disk population. The co-added high-resolution spectra show that that it is a metal poor ([Fe/H] = - 0.53 ± 0.05 dex) and α-rich somewhat evolved solar-like star of spectral type G3. We find Teff = 5730 ± 50 K, log g⋆ = 4.15 ± 0.1 cgs, and derive a radius of R⋆ = 1.3 ± 0.1 R⊙ and a mass of M⋆ = 0.88 ± 0.02 M⊙. The currently available radial velocity data confirms a super-Earth class planet with a mass of 8.6 ± 3.9 M⊕ and a radius of 1.9 ± 0.2 R⊕. A second more massive object with a period longer than about 120 days is indicated by a long-term radial velocity drift. Conclusions: The radial velocity detection together with the imaging confirms with a high level of significance that the transit signature is caused by a planet orbiting the star K2-111. This planet is also confirmed in the radial velocity data. A second more

  11. Short to long-term evolution of the shoreline and the subaerial sand beach driven by extreme forcings : Wan-Tzu-Liao, Taïwan

    Science.gov (United States)

    Campmas, Lucie; Bouchette, Frederic; Meulé, Samuel; Sous, Damien; Liou, Jiing-Yih; Leroux-Mallouf, Romain; Sabatier, François; Hwung, Hwung-Hweng

    2015-04-01

    This study aims at investigating the interactions between wave conditions, water level and morphology of a sand barrier driven by paroxysmal conditions over instantaneous swash event, storm event, monsoon/typhoons seasons and decadal time scales. In the framework of the KUN-SHEN project, 7 months of monitoring (2011-2012) provided 20 topobathymetric surveys (from the subtidal zone to the back-barrier) and acquisitions of offshore, nearshore and shallow water hydrodynamics including velocity profiling, free surface measurement and absolute pressure. Offshore waves were extracted at Cigu buoy (18 m of water depth). Nearshore waves were acquired from the current profiler deployed 400 m off the coast in 4 m of water depth and water level on the subaerial beach were acquired from pressure sensors deployed from the subtidal zone to the dune crest. Morphologic changes of the emerged beach were monitored using D-GPS each week during the winter monsoon season and just before and after each event during the summer typhoons season. The long-term shoreline changes (1993-2009) of the sand barrier is based on aerial photographs and satellites images. The short-term study focus on the sand bed elevation changes associated with individual swash events during the most energetic storm recorded. During this Talim tropical storm (offshore significant wave height up to 10.3 m with period about 14.6 s), pressure sensors deployed in the subaerial beach display a sand bed nourishment about +3.02 cm/h during the storm rising. The numerous swash-swash interactions during the falling period of the storm appear more erosive. Morphological changes of Talim storm in the whole emerged beach included 6.7 m of dunefoot retreat and a sand transfer from a dune breach to wash-over deposits in the lagoon. Additionally, the foreshore was nourished +2261 m3 +/-268 m3 as well as the whole sand barrier (+1920 m3 +/-1071 m3). The summer season of typhoons appears to be an accretive period (3556 m3 +/-1071

  12. Effects of Pre - Season Short - Term Daily Undulating Periodized Training on Muscle Strength and Sprint Performance of Under - 20 Soccer Players

    Directory of Open Access Journals (Sweden)

    Charles Ricardo L OPES

    2015-06-01

    Full Text Available The aim of this study was to evaluate the effects of daily undulating training periodization designed for maximal lower limb muscle strength and sprint performance in under - 20 soccer players. Twenty - four male athletes (age = 19.1 ± 1.2 yr; mass = 71.1 ± 6. 8 kg; height = 178.0 ± 0.1 cm participated in four weeks of a daily undulating periodized (DUP training soccer program. During the pre - and post - training periods the subjects performed a one repetition maximum (1 RM half back squat test and a 15 - meter s print. Significant training - induced changes were observed in sprint times (pre = 2.38 ± 0.01 s; post = 2.31 ± 0.02 s and 1 RM tests (pre = 107.0 ± 2.0 kg; post = 128.0 ± 2.2 kg. These results indicate that a DUP program is efficient in promoting positive neuromuscular adaptations in soccer players, even with a short - term preseason training period.

  13. Earthquake focal mechanisms and stress field in Si-chuan-Yunnan area determined using P wave po-larity and short period P and S waveform data

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Based on waveform data, several methods to determine focal mechanisms of small earthquakes were developed since 1980. Kisslinger (1980) and Julian, Foulger (1996) proposed an approach to determine solution by using amplitude ratio of P and S wave. Schwartz (1995) devised a method to determine solutions by the use of polarity data and amplitudes of seismogram envelopes. Amplitudes of short period seismic waves propagating in an inhomogene-ous medium are sensitive to the variation in velocity and Q structure. Nakamura, et al (1999) took medium inhomo-geneity into account in determining focal mechanisms of small earthquakes using waveform data. If the locations of small earthquakes are concentrated in a small region, we can assume that the raypaths from the events to a given station are almost the same. So P and S wave attenuations are independent of event locations. In this case it is con-venient to determine focal mechanisms of these events by using short period P and S wave dataj. Focal mechanism solutions of small earthquakes in 5 regions, i.e., Rongchang, Mabian-Muchuan, Ya¢an, Baoxing and Mianzhu, which are covered by the Chengdu Telemetered Network, are obtained by analyzing the P polarity and short body wave amplitude data recorded in the network since 1992. According to the method proposed by Gephart and Forsyth (1984), based on well determined focal mechanism solutions in 15 sub-zones of Sichuan and Yunnan area, three principal stress tensors s1, s2, and s3, instead of averages of P, B, and T axis of the solutions, are determined to represent the regional stress field distribution.

  14. Ultra-short-period W/B4C multilayers for x-ray optics-microstructure limits on reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Walton, Christopher Charles [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-12-01

    Multilayer thin films are used as Bragg reflectors for soft x-rays in the energy range 50eV < E < 1000eV in many x-ray optics applications such as x-ray microscopes and telescopes, reducing optics for extreme ultraviolet (EUV) lithography, and x-ray polarizers and phase retarders. Applications often depend critically on reflectivity, which has not been systematically characterized for multilayer periods below 20Å. For this study, W/B4C multilayers were fabricated by magnetron sputtering on Si(111), with periods from 48Å to as little as 4.7Å. The x-ray reflectivity measured at λ = 1.54Å and at 45° incidence (289 eV < E < 860 eV) was found to decrease sharply for multilayer periods less than 15-20Å. Examination by high-resolution transmission electron microscopy (HRTEM) showed an expansion of the thickness of the W-rich layers of 30-40% from the nominal values, consistent with intermixture of the two materials during sputter growth, and discontinuous W-rich layers for multilayer periods below about 15Å. The experimental data for the specular reflectivity in the hard and soft x-ray regimes and the diffuse scattering fit well to a model of multilayer roughness. The model is expressed as a power-law dependence of roughness on spatial frequency. Analysis of small-angle scattering in transmission from multilayers grown on freestanding Si3N4 membranes confirms the onset of discontinuity at periods between 14Å and 22Å. Spectroscopy studies by x-ray absorption (NEXAFS) and electron energy loss (EELS) at the boron K-edge (188eV) are consistent with changes in the average boron bonding environment, as the multilayer period decreases and the W-rich layers are increasingly thin and dispersed. A discrete W-rich phase is present for periods at least as small as 6.3Å.

  15. Ultra-short-period W/B{sub 4}C multilayers for x-ray optics-microstructure limits on reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Walton, C C [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-12-01

    Multilayer thin films are used as Bragg reflectors for soft x-rays in the energy range 50eV < E < 1000eV in many x-ray optics applications such as x-ray microscopes and telescopes, reducing optics for extreme ultraviolet (EUV) lithography, and x-ray polarizers and phase retarders. Applications often depend critically on reflectivity, which has not been systematically characterized for multilayer periods below 20{angstrom}. For this study, W/B{sub 4}C multilayers were fabricated by magnetron sputtering on Si(111), with periods from 48{angstrom} to as little as 4.7{angstrom}. The x-ray reflectivity measured at {lambda} = 1.54{angstrom} and at 45{degrees} incidence (289 eV < E < 860 eV) was found to decrease sharply for multilayer periods less than 15-20{angstrom}. Examination by high-resolution transmission electron microscopy (HRTEM) showed an expansion of the thickness of the W-rich layers of 30-40% from the nominal values, consistent with intermixture of the two materials during sputter growth, and discontinuous W-rich layers for multilayer periods below about 15{angstrom}. The experimental data for the specular reflectivity in the hard and soft x-ray regimes and the diffuse scattering fit well to a model of multilayer roughness. The model is expressed as a power-law dependence of roughness on spatial frequency. Analysis of small-angle scattering in transmission from multilayers grown on freestanding Si{sub 3}N{sub 4} membranes confirms the onset of discontinuity at periods between 14{angstrom} and 22{angstrom}. Spectroscopy studies by x-ray absorption (NEXAFS) and electron energy loss (EELS) at the boron K-edge (188eV) are consistent with changes in the average boron bonding environment, as the multilayer period decreases and the W-rich layers are increasingly thin and dispersed. A discrete W-rich phase is present for periods at least as small as 6.3{angstrom}.

  16. A short period of fasting before surgery conserves basal metabolism and suppresses catabolism according to indirect calorimetry performed under general anesthesia.

    Science.gov (United States)

    Yoshimura, Shinichiro; Fujita, Yoshihito; Hirate, Hiroyuki; Kusama, Nobuyoshi; Azami, Takafumi; Sobue, Kazuya

    2015-06-01

    It is recommended that the period of fasting before elective surgery should be shortened to facilitate a rapid recovery by preventing catabolism. We examined the effects of a short period of fasting on metabolism by performing indirect calorimetry (IC) under general anesthesia. A prospective observational study involving 26 consecutive patients who underwent elective surgery and whose metabolism was evaluated using IC during anesthesia was conducted. The patients were divided into two groups, those who fasted for 10 h (group L). Oxygen consumption, the volume of carbon dioxide emissions (VCO2), the respiratory quotient (RQ), resting energy expenditure (REE), and basal energy expenditure (BEE) were compared. The REE, VCO2, and RQ of group L (17.7 ± 2.3 kcal/kg/day, 118.5 ± 20.8 ml/min, and 0.71 ± 0.12, respectively) were significantly lower than those of group S (19.7 ± 2.3 kcal/kg/day, 143.6 ± 30.9 ml/min, and 0.81 ± 0.09, respectively) (P < 0.05). In group L, the relationship between REE and BEE was weaker (r(2) = 0.501) and the BEE-REE slope was less steep (REE = 0.419BEE + 509.477) than those seen in group S (r(2) = 0.749 and REE = 1.113BEE - 376.111, respectively). Our findings suggest that a short period of fasting (<8 h) before surgery is more strongly associated with the conservation of basal metabolism.

  17. 超低速直流电机电刷短路系数计算%Computation of brush short-circuit coefficients of DC machines for extremely low speed drives

    Institute of Scientific and Technical Information of China (English)

    张琪; 谢国栋; 黄苏融

    2006-01-01

    Short circuit due to the brushes over the commutator segments of DC machines causes reduction in the armature resistance and flux linkage, which is especially meaningful when the electric machine is running at zero or extremely low speed. In design computation of DC machines, usually the average values of the coefficients are used in consideration of the effects of the short circuit.However, the average values have complicated relationships with the parameters of electric machines, therefore, no usable mathematical model has been established yet for precise computation. In this paper, a relatively simple and generalized method for precise computation of the average values of the short-circuit coefficients is proposed. This method decouples some of the machine parameters and, therefore establishes a highly parameterized mathematical model and is convenient in formulation for computation. In addition, the computation data for one and two brush pairs, which are the most common cases, is provided.

  18. Whole Earth Telescope Observations of the subdwarf B star KPD 1930+2752: A rich, short period pulsator in a close binary

    CERN Document Server

    Reed, M D; Poindexter, S; Zhou, A -Y; Eggen, J R; Morris, M A; Quint, A C; McDaniel, S; Baran, A; Dolez, N; Kawaler, S D; Kurtz, D W; Moskalik, P; Riddle, R; Zola, S; Ostensen, R H; Solheim, J -E; Kepler, S O; daCosta, A; Provencal, J L; Mullally, F; Winget, D W; Vuckovic, M; Crowe, R; Terry, D; Avila, R; Berkey, B; Stewart, S; Bodnarik, J; Bolton, D; Binder, P -M; Sekiguchi, K; Sullivan, D J; Kim, S -L; Chen, W -P; Chen, C -W; Lin, H -C; Jian, X -J; Wu, H; Gou, J -P; Liu, Z; Leibowitz, E; Lipkin, Y; Akan, C; Janulis, R; Pretorius, R; Ogloza, W; Stachowski, G; Paparo, M; Szabo, R; Csubry, Z; Zsuffa, D; Silvotti, R; Marinoni, S; Bruni, I; Vauclair, G; Chevreton, M; Matthews, J M; Cameron, C; Pablo, H

    2010-01-01

    KPD 1930+2752 is a short-period pulsating subdwarf B (sdB) star. It is also an ellipsoidal variable with a known binary period just over two hours. The companion is most likely a white dwarf and the total mass of the system is close to the Chandresakhar limit. In this paper we report the results of Whole Earth Telescope (WET) photometric observations during 2003 and a smaller multisite campaign from 2002. From 355 hours of WET data, we detect 68 pulsation frequencies and suggest an additional 13 frequencies within a crowded and complex temporal spectrum between 3065 and 6343 $\\mu$Hz (periods between 326 and 157 s). We examine pulsation properties including phase and amplitude stability in an attempt to understand the nature of the pulsation mechanism. We examine a stochastic mechanism by comparing amplitude variations with simulated stochastic data. We also use the binary nature of KPD 1930+2752 for identifying pulsation modes via multiplet structure and a tidally-induced pulsation geometry. Our results indic...

  19. Trends in the incidence of lower extremity amputations in people with and without diabetes over a five-year period in the Republic of Ireland.

    LENUS (Irish Health Repository)

    Buckley, Claire M

    2012-01-01

    To describe trends in the incidence of non-traumatic amputations among people with and without diabetes and estimate the relative risk of an individual with diabetes undergoing a lower extremity amputation compared to an individual without diabetes in the Republic of Ireland.

  20. Hydrometeorological extremes at the Veselí nad Moravou estate (Czech Republic) in the period 1794-1850 derived from documentary evidence of the economic character

    Science.gov (United States)

    Chromá, Kateřina

    2010-05-01

    Hydrometeorological extremes influenced always human activities (agriculture, forestry, water management) and caused losses of human lives and great material damage. Systematic meteorological and hydrological observations in the Czech Lands (recent Czech Republic) started generally in the latter half of the 19th century. In order to create long-term series of hydrometeorological extremes, it is necessary to search for other sources of information for their study before 1850. Such direct and indirect information about hydrometeorological extremes is included in documentary evidence (e.g. chronicles, memoirs, diaries, early visual weather observations, newspapers, economic sources etc.). Documentary evidence of economic character belongs to the most important sources, especially documents related to taxation records. Damage to agricultural crops on the fields or damage to hay on meadows due to the hydrological and meteorological phenomena has been a good reason for the abatement of tax duty. Based on the official correspondence of the estate of Veselí nad Moravou (southern Moravia), archival information about taxation from the Moravian Land Archives in Brno was excerpted. Based on it, 46 hydrometeorological extremes which occurred between the years 1794 and 1850 were selected and further analysed. Because of fields and meadows of the above estate were located along the Morava River, reports of damage due to floods were the most frequent, followed by damage due to torrential rains and hailstorms.

  1. A short-term extremely low frequency electromagnetic field exposure increases circulating leukocyte numbers and affects HPA-axis signaling in mice

    NARCIS (Netherlands)

    Kleijn, de Stan; Ferwerda, Gerben; Wiese, Michelle; Trentelman, Jos; Cuppen, Jan; Kozicz, Tamas; Jager, de Linda; Hermans, Peter W.M.; Kemenade, van Lidy

    2016-01-01

    There is still uncertainty whether extremely low frequency electromagnetic fields (ELF-EMF) can induce health effects like immunomodulation. Despite evidence obtained in vitro, an unambiguous association has not yet been established in vivo. Here, mice were exposed to ELF-EMF for 1, 4, and 24 h/d

  2. Short-interval leg movements during sleep entail greater cardiac activation than periodic leg movements during sleep in restless legs syndrome patients.

    Science.gov (United States)

    Ferri, Raffaele; Rundo, Francesco; Silvani, Alessandro; Zucconi, Marco; Aricò, Debora; Bruni, Oliviero; Lanuzza, Bartolo; Ferini-Strambi, Luigi; Manconi, Mauro

    2017-10-01

    Periodic leg movements during sleep (PLMS) are sequences of ≥4 motor events with intermovement intervals (IMI) of 10-90 s. PLMS are a supportive diagnostic criterion for restless legs syndrome (RLS) and entail cardiac activation, particularly when associated with arousal. RLS patients also over-express short-interval leg movements during sleep (SILMS), which have IMI leg movements. We found that the duration of the R-R interval decrease with SILMS doublets was significantly longer than that with PLMS, whereas the maximal decrease in R-R interval was similar. Scoring SILMS in RLS patients may therefore be relevant from a cardiac autonomic perspective. © 2017 European Sleep Research Society.

  3. pH-sensing properties of cascaded long- and short-period fiber grating with poly acrylic acid/poly allylamine hydrochloride thin-film overlays

    Science.gov (United States)

    Yang, Ying

    2014-11-01

    Based on coupled-mode theory and transfer matrix method, the mode coupling mechanism and the reflection spectral properties of coated cascaded long- and short-period gratings (CLBG) are discussed. The effects of the thin-film parameters (film refractive index and film thickness) on the reflection spectra of the coated CLBG are simulated. By using electrostatic self-assembly method, poly acrylic acid (PAA) and poly allylamine hydrochloride (PAH) multilayer molecular pH-sensitive thin-films are assembled on the surface of the partial corroded CLBG. When the CLBG coated with PAA/PAH films are used to sense pH values, the resonant wavelengths of the CLBG have almost no shift, whereas the resonance peak reflectivities change with pH values. In addition, the sensitivities of the resonance peak reflectivities responding to pH values are improved by an order of magnitude.

  4. Probing the origin of quasi-periodic oscillations: the short-timescale evolution of phase lags in GRS 1915+105

    CERN Document Server

    Eijnden, Jakob van den; Uttley, Phil

    2016-01-01

    We present a model-independent analysis of the short-timescale energy dependence of low frequency quasi-periodic oscillations (QPOs) in the X-ray flux of GRS 1915+105. The QPO frequency in this source has previously been observed to depend on photon energy, with the frequency increasing with energy for observations with a high ($\\gtrsim 2$ Hz) QPO frequency, and decreasing with energy for observations with a low ($\\lesssim 2$ Hz) QPO frequency. As this observed energy dependence is currently unexplained, we investigate if it is intrinsic to the QPO mechanism by tracking phase lags on (sub)second timescales. We find that the phase lag between two broad energy bands systematically increases for $5$ - $10$ QPO cycles, after which the QPO becomes decoherent, the phase lag resets and the pattern repeats. This shows that the band with the higher QPO frequency is running away from the other band on short timescales, providing strong evidence that the energy dependence of the QPO frequency is intrinsic. We also find ...

  5. A dearth of short-period massive binaries in the young massive star forming region M 17. Evidence for a large orbital separation at birth?

    Science.gov (United States)

    Sana, H.; Ramírez-Tannus, M. C.; de Koter, A.; Kaper, L.; Tramper, F.; Bik, A.

    2017-03-01

    Aims: The formation of massive stars remains poorly understood and little is known about their birth multiplicity properties. Here, we aim to quantitatively investigate the strikingly low radial-velocity dispersion measured for a sample of 11 massive pre- and near-main-sequence stars (σ1D= 5.6 ± 0.2 km s-1) in the very young massive star forming region M 17, in order to obtain first constraints on the multiplicity properties of young massive stellar objects. Methods: We compute the radial-velocity dispersion of synthetic populations of massive stars for various multiplicity properties and we compare the obtained σ1D distributions to the observed value. We specifically investigate two scenarios: a low binary fraction and a dearth of short-period binary systems. Results: Simulated populations with low binary fractions () or with truncated period distributions (Pcutoff > 9 months) are able to reproduce the low σ1D observed within their 68%-confidence intervals. Furthermore, parent populations with fbin > 0.42 or Pcutoff star formation process. In the context of the second scenario, compact binaries must form later on, and the cut-off period may be related to physical length-scales representative of the bloated pre-main-sequence stellar radii or of their accretion disks. Conclusions: If the obtained constraints for the M 17's massive-star population are representative of the multiplicity properties of massive young stellar objects, our results may provide support to a massive star formation process in which binaries are initially formed at larger separations, then harden or migrate to produce the typical (untruncated) power-law period distribution observed in few Myr-old OB binaries.

  6. BD Andromedae: A new short-period RS CVn eclipsing binary star with a distant tertiary body in a highly eccentric orbit

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chun-Hwey; Song, Mi-Hwa; Yoon, Jo-Na; Jeong, Min-Ji [Department of Astronomy and Space Science, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Han, Wonyong, E-mail: kimch@chungbuk.ac.kr [Korea Astronomy and Space Institute, Daejeon 305-348 (Korea, Republic of)

    2014-06-20

    A photometric study of BD And was made through the analysis of two sets of new BVR light curves. The light curves with migrating photometric waves outside eclipse show that BD And is a short-period RS CVn-type binary star. The analysis of all available timings reveals that the orbital period has varied in a strictly cyclical way with a period of 9.2 yr. The periodic variation most likely arises from the light-time effect due to a tertiary moving in a highly elliptical orbit (e {sub 3} = 0.76). The Applegate mechanism could not operate properly in the eclipsing pair. The light curves were modeled with two large spots on the hotter star and a large third light amounting to about 14% of the total systemic light. BD And is a triple system: a detached binary system consisting of two nearly equal solar-type stars with an active primary star and a G6-G7 tertiary dwarf. The absolute dimensions of the eclipsing pair and tertiary components were determined. The three components with a mean age of about 5.8 Gyr are located at midpositions in main-sequence bands. The radius of the secondary is about 17% larger than that deduced from stellar models. The orbital and radiometric characteristics of the tertiary are intensively investigated. One important feature is that the mutual inclination between two orbits is larger than 60°, implying that Kozai cycles had occurred very efficiently in the past. The possible past and future evolutions of the BD And system, driven by KCTF and MBTF, are also discussed.

  7. X-ray standing-wave study of (AlAs){sub m}(GaAs){sub n} short-period superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Lessmann, A.; Brennan, S.; Munkholm, A. [Stanford Synchrotron Radiation Laboratory SSRL/SLAC, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Schuster, M.; Riechert, H. [Siemens AG, Corporate Technology, Otto-Hahn-Ring 6, D-81739 Munich (Germany); Materlik, G. [Hamburger Synchrotronstrahlungslabor HASYLAB am Deutschen Elektronen-Synchrotron DESY, Notkestrasse 85, D-22603 Hamburg (Germany)

    1999-04-01

    X-ray standing-waves (XSW) are used for an investigation of the structure of (AlAs){sub m}(GaAs){sub n} short-period superlattices (SL{close_quote}s). The XSW induced modulation of x-ray fluorescence from the Al, As, and Ga atoms and the total photoelectron yield are monitored around the 0th order SL satellite (AlAs)(GaAs)(004,0) and the GaAs(004) substrate Bragg reflection. From the specific shape of these modulations and the sample reflectivity, an atomic model about the interfaces is derived. This is accomplished by comparing the experimental data with dynamical calculations of x-ray wavefield distribution and reflectivity, which are based on the Takagi-Taupin equation. The fluorescence measurements at the 0th order SL satellite reveal a high crystalline order in the AlAs layers of the short-period SL, whereas in the GaAs layers, a fraction of the Ga and As atoms is not on the ideal lattice positions. From the analysis, a model of the atomic distribution along the [001] direction can be determined. This reveals that at each internal interface in the GaAs layers, two Ga atom planes are shifted by up to 0.035 nm and one As atom plane by 0.023 nm. At each interface, the shifts are directed towards the substrate. In addition, the XSW field at the GaAs(004) substrate reflection results in a moir{acute e} or beating effect in the SL structure, which can be used to determine the information depth {Lambda}{sub e} of total electron-yield measurements in a more detailed approach. {copyright} {ital 1999} {ital The American Physical Society}

  8. Possible link of sudden onset and short-time periodic pulsation of polar mesosphere summer echoes to ULF Pc5 geomagnetic pulsations and solar wind dynamic pressure enhancement

    Science.gov (United States)

    Lee, Y.; Kirkwood, S.; Kwak, Y. S.

    2016-12-01

    The EISCAT VHF incoherent scatter radar in Tromsö, Norway, makes occasional observations of electron densities and Polar Mesosphere Summer Echoes, in the summer polar D-region ionosphere. In one of those datasets, pulsating polar mesospheric summer echoes (PMSE) are observed, with periodicities in the ultra-low frequency (ULF) Pc5 band (1.6-6.7 mHz), following an abrupt increase of the radar reflectivity when a geomagnetic field excursion is started, in turn linked to dynamic pressure (Pdyn) enhancement in the solar wind. At the excursion of the magnetic field, at auroral altitudes of 90 km and above, electron density is abruptly enhanced, followed by a series of short-lived peaks, superimposed on an enhanced level. The short-lived peaks are likely a signature of transient Pc5 geomagnetic pulsations and associated energetic electron precipitation from pitch-angle scattering into the loss cone in the magnetosphere. At the same time, at altitudes around 80-90 km, a sharp increase of PMSE reflectivity occurs, 100 times greater than the increase of electron density, and is followed by pulsating PMSE reflectivity with periodicities in the Pc5 band, increasing and decreasing in magnitude during the course of the next hour. The increase of the pulsation magnitude may be attributed to an increase of high-energy electron precipitation flux ( >30 keV) penetrating to at least the height of maximum PMSE reflectivity. This study suggests that Pc5 pulsation bursts in both magnetic field and high energy electron precipitation could play a crucial role in producing PMSE fluctuations on minute-to-minute time scales.

  9. Origin and Ubiquity of Short-Period Earth-like Planets: Evidence for the Sequential-Accretion Theory of Planet Formation

    CERN Document Server

    Zhou, J L; Lin, D N C; Nagasawa, M

    2005-01-01

    The formation of gas giant planets is assumed to be preceded by the emergence of solid cores in the conventional sequential-accretion paradigm. This hypothesis implies that the presence of earth-like planets can be inferred from the detection of gas giants. A similar prediction cannot be made with the gravitational instability (hereafter GI) model which assumes that gas giants (hereafter giants) formed from the collapse of gas fragments analogous to their host stars. We propose an observational test for the determination of the dominant planet-formation channel. Based on the sequential-accretion (hereafter SA) model, we identify several potential avenues which may lead to the prolific formation of a population of close-in earth-mass ($M_\\oplus$) planets (hereafter close-in earths) around stars with 1) short-period or 2) solitary eccentric giants and 3) systems which contain intermediate-period resonant giants. In contrast, these close-in earths are not expected to form in systems where giants originated rapid...

  10. Constraining the formation of black-holes in short-period Black-Hole Low-Mass X-ray Binaries

    CERN Document Server

    Repetto, Serena

    2015-01-01

    The formation of stellar mass black holes is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova event (if any) and the magnitude of the natal kick the black hole receives at birth (if any). Repetto et al. (2012), studying the position of Galactic X-ray binaries containing black holes, found evidence for black holes receiving high natal kicks at birth. In this Paper we extend that study, taking into account the previous binary evolution of the sources as well. The seven short-period black-hole X-ray binaries that we use, are compact binaries consisting of a low-mass star orbiting a black hole in a period less than $1$ day. We trace their binary evolution backwards in time, from the current observed state of mass-transfer, to the moment the black hole was formed, and we add the extra information on the kinematics of the binaries. We find that several systems could be explained by no natal kick, just mass ejection, while for two systems (and possibly more) a high kick is...

  11. Algorithm of brush short-circuit coefficients of DC machines for extremely low speed drives%极低速驱动用直流电机电刷短路系数的算法

    Institute of Scientific and Technical Information of China (English)

    张琪; 谢国栋; 黄苏融

    2008-01-01

    When a direct-current (DC) machine runs at extremely low speed or standstill, the reduction in the armature resistance and the armature flux linkage due to the short circuited coils by the brushes on the commutator should not be neglected. Taking this reduction effect into account, the average values of the reduction coefficients relate to the machine parameters in complicated forms. In this paper, an effective algorithm for the precise computation of the average values of these reduction coefficients is proposed. Furthermore, in the algorithm, the effect of the insulation thickness between the commutator segments and the multiplicity of the wave winding are considered for the first time. The proposed algorithm can also be accommodated into the computer-aided design (CAD) of a DC machine, which normally runs at extremely low speed or standstill.

  12. [The effects of 16-weeks pilates mat program on anthropometric variables and body composition in active adult women after a short detraining period].

    Science.gov (United States)

    Vaquero-Cristóbal, Raquel; Alacid, Fernando; Esparza-Ros, Francisco; Muyor, José M; López-Miñarro, Pedro Ángel

    2015-04-01

    previous studies have analysed the effect of mat Pilates practice on anthropometric variables and body composition in sedentaries. To date no researchs have investigated the benefits of Pilates on these variables after a short detraining period. to determine the effect of a 16-week mat Pilates program on anthropometric variables, body composition and somatotype of women with previous practice experience after three weeks of detraining period. twenty-one women underwent a complete anthropometric assessment according with ISAK guidelines before and after a 16 week mat Pilates program (two days, one hour). All women had one to three years of mat Pilates experience and came to three weeks of detraining period (Christmas holiday). women showed significant decreases for body mass, BMI, upper limb (biceps and triceps) and trunk (subscapular, iliac crest, supraspinale and abdominal) individual skinfolds, 6 and 8 skinfold sums, endomorphy and fat mass; and a significant increases for muscle mass. The mean somatotype was classified as mesomorphic endomorph in the pre- (4.91, 4.01, 1.47) and post-test (4.68, 4.16, 1.69). Eight women changed their somatotype clasification after the intervention program. the practice of mat Pilates for 16 weeks caused changes associated with health state improvements on anthropometric variables, especially on skinfolds which significantly decreased, body composition (fat and muscle masses decreased and increased, respectively) and somatotype (there was a significantly decreased on the endomorph component in experienced women after three week of detraning. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  13. X-ray standing wave studies of strained InxGa1-xAs/InP short-period superlattices

    Science.gov (United States)

    Aruta, Carmela; Lamberti, Carlo; Gastaldi, Luigi; Boscherini, Federico

    2003-05-01

    We report an x-ray standing wave (XSW) study on a set of structurally well-characterized InxGa1-xAs/InP short-period superlattices grown by metal-organic chemical vapor deposition and chemical-beam epitaxy techniques. It was possible to model the x-ray standing wave profiles only once the superlattice period has been assumed to be constituted by four layers of well-defined chemical composition [barrier (InP), first interface (InAs0.7P0.3), well (In0.53Ga0.47As), and second interface (In0.53Ga0.47As0.7P0.3)], and of variable thickness. The thickness of the four layers have been obtained by fitting the high resolution x-ray diffraction profiles of the heterostructures. The presence of partially disordered interface layers, as evidenced by a transmission electron microscopy study, causes a significant reduction of the coherent fraction, F, of both Ga and As atoms. The difference in F values among measured samples illustrates how the XSW can provide important information on the quality of semiconductor superlattices. Comparison with a "long period (160 Å)" In0.53Ga0.47As/InP superlattice, where the role played by InAs0.7P0.3 and In0.53Ga0.47As0.7P0.3 interface layers is negligible, confirms this picture. The coherent fraction of both As and Ga correlates well with the average perpendicular lattice misfit determined by x-ray diffraction.

  14. Probability Estimates of Solar Particle Event Doses During a Period of Low Sunspot Number for Thinly-Shielded Spacecraft and Short Duration Missions

    Science.gov (United States)

    Atwell, William; Tylka, Allan J.; Dietrich, William; Rojdev, Kristina; Matzkind, Courtney

    2016-01-01

    In an earlier paper (Atwell, et al., 2015), we investigated solar particle event (SPE) radiation exposures (absorbed dose) to small, thinly-shielded spacecraft during a period when the sunspot number (SSN) was less than 30. These SPEs contain Ground Level Events (GLE), sub-GLEs, and sub-sub-GLEs (Tylka and Dietrich, 2009, Tylka and Dietrich, 2008, and Atwell, et al., 2008). GLEs are extremely energetic solar particle events having proton energies extending into the several GeV range and producing secondary particles in the atmosphere, mostly neutrons, observed with ground station neutron monitors. Sub-GLE events are less energetic, extending into the several hundred MeV range, but do not produce secondary atmospheric particles. Sub-sub GLEs are even less energetic with an observable increase in protons at energies greater than 30 MeV, but no observable proton flux above 300 MeV. In this paper, we consider those SPEs that occurred during 1973-2010 when the SSN was greater than 30 but less than 50. In addition, we provide probability estimates of absorbed dose based on mission duration with a 95% confidence level (CL). We also discuss the implications of these data and provide some recommendations that may be useful to spacecraft designers of these smaller spacecraft.

  15. Differences in spatio-temporal behavior of zebrafish in the open tank paradigm after a short-period confinement into dark and bright environments.

    Science.gov (United States)

    Rosemberg, Denis B; Rico, Eduardo P; Mussulini, Ben Hur M; Piato, Angelo L; Calcagnotto, Maria E; Bonan, Carla D; Dias, Renato D; Blaser, Rachel E; Souza, Diogo O; de Oliveira, Diogo L

    2011-05-02

    The open tank paradigm, also known as novel tank diving test, is a protocol used to evaluate the zebrafish behavior. Several characteristics have been described for this species, including scototaxis, which is the natural preference for dark environments in detriment of bright ones. However, there is no evidence regarding the influence of "natural stimuli" in zebrafish subjected to novelty-based paradigms. In this report, we evaluated the spatio-temporal exploratory activity of the short-fin zebrafish phenotype in the open tank after a short-period confinement into dark/bright environments. A total of 44 animals were individually confined during a 10-min single session into one of three environments: black-painted, white-painted, and transparent cylinders (dark, bright, and transparent groups). Fish were further subjected to the novel tank test and their exploratory profile was recorded during a 15-min trial. The results demonstrated that zebrafish increased their vertical exploratory activity during the first 6-min, where the bright group spent more time and travelled a higher distance in the top area. Interestingly, all behavioral parameters measured for the dark group were similar to the transparent one. These data were confirmed by automated analysis of track and occupancy plots and also demonstrated that zebrafish display a classical homebase formation in the bottom area of the tank. A detailed spatio-temporal study of zebrafish exploratory behavior and the construction of representative ethograms showed that the experimental groups presented significant differences in the first 3-min vs. last 3-min of test. Although the main factors involved in these behavioral responses still remain ambiguous and require further investigation, the current report describes an alternative methodological approach for assessing the zebrafish behavior after a forced exposure to different environments. Additionally, the analysis of ethologically-relevant patterns across time could

  16. Are hourly precipitation extremes increasing faster than daily precipitation extremes?

    Science.gov (United States)

    Barbero, Renaud; Fowler, Hayley; Blenkinsop, Stephen; Lenderink, Geert

    2016-04-01

    Extreme precipitation events appear to be increasing with climate change in many regions of the world, including the United States. These extreme events have large societal impacts, as seen during the recent Texas-Oklahoma flooding in May 2015 which caused several billion in damages and left 47 deaths in its path. Better understanding of past changes in the characteristics of extreme rainfall events is thus critical for reliable projections of future changes. Although it has been documented in several studies that daily precipitation extremes are increasing across parts of the contiguous United States, very few studies have looked at hourly extremes. However, this is of primary importance as recent studies on the temperature scaling of extreme precipitation have shown that increases above the Clausius-Clapeyron (~ 7% °C-1) are possible for hourly precipitation. In this study, we used hourly precipitation data (HPD) from the National Climatic Data Center and extracted more than 1,000 stations across the US with more than 40 years of data spanning the period 1950-2010. As hourly measurements are often associated with a range of issues, the data underwent multiple quality control processes to exclude erroneous data. While no significant changes were found in annual maximum precipitation using both hourly and daily resolution datasets, significant increasing trends in terms of frequency of episodes exceeding present-day 95th percentiles of wet hourly/daily precipitation were observed across a significant portion of the US. The fraction of stations with significant increasing trends falls outside the confidence interval range during all seasons but the summer. While less than 12% of stations exhibit significant trends at the daily scale in the wintertime, more than 45% of stations, mostly clustered in central and Northern United States, show significant increasing trends at the hourly scale. This suggests that short-duration storms have increased faster than daily

  17. Zodiacal Exoplanets in Time (ZEIT). III. A Short-period Planet Orbiting a Pre-main-sequence Star in the Upper Scorpius OB Association

    Science.gov (United States)

    Mann, Andrew W.; Newton, Elisabeth R.; Rizzuto, Aaron C.; Irwin, Jonathan; Feiden, Gregory A.; Gaidos, Eric; Mace, Gregory N.; Kraus, Adam L.; James, David J.; Ansdell, Megan; Charbonneau, David; Covey, Kevin R.; Ireland, Michael J.; Jaffe, Daniel T.; Johnson, Marshall C.; Kidder, Benjamin; Vanderburg, Andrew

    2016-09-01

    We confirm and characterize a close-in ({P}{{orb}} = 5.425 days), super-Neptune sized ({5.04}-0.37+0.34 {R}\\oplus ) planet transiting K2-33 (2MASS J16101473-1919095), a late-type (M3) pre-main-sequence (11 Myr old) star in the Upper Scorpius subgroup of the Scorpius-Centaurus OB association. The host star has the kinematics of a member of the Upper Scorpius OB association, and its spectrum contains lithium absorption, an unambiguous sign of youth (\\lt 20 Myr) in late-type dwarfs. We combine photometry from K2 and the ground-based MEarth project to refine the planet’s properties and constrain the host star’s density. We determine K2-33’s bolometric flux and effective temperature from moderate-resolution spectra. By utilizing isochrones that include the effects of magnetic fields, we derive a precise radius (6%-7%) and mass (16%) for the host star, and a stellar age consistent with the established value for Upper Scorpius. Follow-up high-resolution imaging and Doppler spectroscopy confirm that the transiting object is not a stellar companion or a background eclipsing binary blended with the target. The shape of the transit, the constancy of the transit depth and periodicity over 1.5 yr, and the independence with wavelength rule out stellar variability or a dust cloud or debris disk partially occulting the star as the source of the signal; we conclude that it must instead be planetary in origin. The existence of K2-33b suggests that close-in planets can form in situ or migrate within ˜10 Myr, e.g., via interactions with a disk, and that long-timescale dynamical migration such as by Lidov-Kozai or planet-planet scattering is not responsible for all short-period planets.

  18. Atmospheric mass loss and evolution of short-period exoplanets: the examples of CoRoT-7b and Kepler-10b

    CERN Document Server

    Kurokawa, Hiroyuki

    2013-01-01

    Short-period exoplanets potentially lose envelope masses during their evolution because of atmospheric escape caused by the intense XUV radiation from their host stars. We develop a combined model of atmospheric mass loss calculation and thermal evolution calculation of a planet to simulate its evolution and explore the dependences on the formation history of the planet. Thermal atmospheric escape as well as the Roche-lobe overflow contributes to mass loss. The maximum initial planetary model mass depends primarily on the assumed evolution model of the stellar XUV luminosity. We adapt the model to CoRoT-7b and Kepler-10b to explore the evolution of both planets and the maximum initial mass of these planets. We take the recent X-ray observation of CoRoT-7 into account and exploring the effect of different XUV evolution models on the planetary initial mass. Our calculations indicate that both hot super Earths could be remnants of Jupiter mass gas planets.

  19. GaAsSb/GaAsN short-period superlattices as a capping layer for improved InAs quantum dot-based optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Utrilla, A. D.; Ulloa, J. M., E-mail: jmulloa@isom.upm.es; Guzman, A.; Hierro, A. [Institute for Systems based on Optoelectronics and Microtechnology (ISOM) and Departamento de Ingeniería Electrónica, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Reyes, D. F.; González, D.; Ben, T. [Departamento de Ciencia de los Materiales e IM y QI, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)

    2014-07-28

    The application of a GaAsSb/GaAsN short-period superlattice capping layer (CL) on InAs/GaAs quantum dots (QDs) is shown to be an option for providing improved luminescence properties to this system. Separating both GaAsSb and GaAsN ternaries during the growth in 2 monolayer-thick phases solves the GaAsSbN immiscibility-related problems. Strong fluctuations in the CL composition and strain field as well as in the QD size distribution are significantly reduced, and a more regular CL interface is also obtained. Room-temperature (RT) photoluminescence (PL) is obtained for overall N contents as high as 3%, yielding PL peak wavelengths beyond 1.4 μm in samples with a type-II band alignment. High external quantum efficiency electroluminescence and photocurrent from the QD ground state are also demonstrated at RT in a single QD-layer p-i-n device. Thus, it becomes possible to combine and transfer the complementary benefits of Sb- and N-containing GaAs alloys to InAs QD-based optoelectronics.

  20. Properties of the short period CoRoT-planet population II: The impact of loss processes on planet masses from Neptunes to Jupiters

    CERN Document Server

    Lammer, H; Wuchterl, G; Lichtenegger, H I M; Khodachenko, M L; Kulikov, Y N; Micela, G; Lammer, Helmut; Kulikov, Yu. N.

    2007-01-01

    The orbital distance at which close-in exoplanets maintain their initial mass is investigated by modelling the maximum expected thermal and nonthermal mass loss rates over several Gyr. Depending on an exosphere formation time and the evolution of the stellar X-ray and EUV flux we expect that thermal evaporation at orbital distances less than 0.05 AU may be an efficient loss process for hydrogen-rich exoplanets with masses less than 0.25 MJup. Our results indicate that nonthermal mass loss induced by Coronal Mass Ejections of the host star can significantly erode weakly magnetized short periodic gas giants. The observed exoplanets Gliese 876d at 0.0208 AU with a mass of about 0.033 MJup and 55 Cnc e at 0.045 AU with a mass of about 0.038 MJup could be strongly eroded gas giants, while HD69830b, at 0.078 AU, HD160691d at 0.09 AU and HD69830c at 0.18 AU belonged most likely since their origin to the Neptune-mass domain. The consequences for the planetary population predicted in paper I (Wuchterl et al. 2006) for...

  1. Band gap engineering of ZnSnN2/ZnO (001) short-period superlattices via built-in electric field

    Science.gov (United States)

    Fang, D. Q.; Zhang, Y.; Zhang, S. L.

    2016-12-01

    Using density-functional-theory calculations combined with hybrid functional, we investigate the band gaps and built-in electric fields of ZnSnN2/ZnO (001) short-period superlattices. The band gap of ZnSnN2/ZnO (001) superlattice can be tuned from 1.9 eV to 0 eV by varying the thickness of both the ZnSnN2 and ZnO regions. Compared to the III-nitride superlattices, stronger built-in electric fields, induced by the polarizations, form inside the ZnSnN2/ZnO superlattices. The lowest electron and uppermost hole states are mainly localized at the two opposite interfaces of the superlattice, but the tails of the lowest electron states extend over several atomic layers. Based on the electrostatic argument, we demonstrate that variations of the band gap are approximately described by a geometric factor. The influence of the in-plane strain is also discussed. The results will be valuable in the design of ZnSnN2/ZnO heterostructures for electronics and optoelectronics applications.

  2. Study on Panax quinquefolius introduction to the mountainous in short frostless period%短无霜期山地引种西洋参的研究

    Institute of Scientific and Technical Information of China (English)

    迟守亮; 连丽敏

    2014-01-01

    采取地膜覆盖技术,在靖宇板石引种西洋参,结果表明,单产为1.26 kg· m-2;总皂甙含量为5.97%,其中,单体皂甙( Rb1)含量为1.41%,氨基酸总量为7.165%,质量符合国标Ⅰ级品指标,产品质量高于原产地。在较短无霜期地区可以引种西洋参。%Panax quinquefolius was introduced in Banshi , Jingyu county by using plastic film mulching technique; the re-sults indicated that yield per unit area was 1.26 kg· m-2.Totle saponin content was 5.97%, saponin monomer content (Rb1)was 1.41%, total amino acides was 7.165%,quality accorded with national standard Ⅰgrade indexes, product qual-ity was higher than the country of origin .Panax quinquefolius could be introducd in short frostless period .

  3. Quantum state engineering with ultra-short-period (AlN)m/(GaN)n superlattices for narrowband deep-ultraviolet detection.

    Science.gov (United States)

    Gao, Na; Lin, Wei; Chen, Xue; Huang, Kai; Li, Shuping; Li, Jinchai; Chen, Hangyang; Yang, Xu; Ji, Li; Yu, Edward T; Kang, Junyong

    2014-12-21

    Ultra-short-period (AlN)m/(GaN)n superlattices with tunable well and barrier atomic layer numbers were grown by metal-organic vapour phase epitaxy, and employed to demonstrate narrowband deep ultraviolet photodetection. High-resolution transmission electron microscopy and X-ray reciprocal space mapping confirm that superlattices containing well-defined, coherently strained GaN and AlN layers as thin as two atomic layers (∼ 0.5 nm) were grown. Theoretical and experimental results demonstrate that an optical absorption band as narrow as 9 nm (210 meV) at deep-ultraviolet wavelengths can be produced, and is attributable to interband transitions between quantum states along the [0001] direction in ultrathin GaN atomic layers isolated by AlN barriers. The absorption wavelength can be precisely engineered by adjusting the thickness of the GaN atomic layers because of the quantum confinement effect. These results represent a major advance towards the realization of wavelength selectable and narrowband photodetectors in the deep-ultraviolet region without any additional optical filters.

  4. Short-term emissions of CO2 and N2O in response to periodic flood irrigation with waste water in the Mezquital Valley of Mexico

    Science.gov (United States)

    González-Méndez, B.; Webster, R.; Fiedler, S.; Loza-Reyes, E.; Hernández, J. M.; Ruíz-Suárez, L. G.; Siebe, C.

    2015-01-01

    Irrigation with waste water adds labile carbon and nitrogen compounds to the soil, and when applied by flooding it rapidly changes the soil's atmosphere and redox potential. In the Mezquital Valley more than 90 000 ha is irrigated with waste water from Mexico City, and enhanced emissions of CO2 and N2O follow each flooding. We measured the emissions of these two gases from a field irrigated periodically with waste water and under three crops, namely alfalfa, rye-grass and maize, using static chambers for 21 months. We also measured emissions from a field growing rain-fed maize before and shortly after two rain events. The data from repeated measurements from the same chambers are correlated in time, and so we modelled the ante-dependence and fitted the models by residual maximum likelihood (REML). The emissions of both CO2 and N2O increased rapidly in response to flood irrigation with peaks up to 448 mg C m-2 hour-1 for CO2 and 2.98 mg N m-2 hour-1 for N2O under maize. Emissions peaked in particular irrigation events either as the infiltrating water replaced the gas from air-filled pores or several days after irrigation as excess nitrogen and fresh sources of carbon were mineralized. Processes operating during the few days during and immediately after irrigation seem to determine the dynamics of gaseous production in this agricultural ecosystem.

  5. Statistical Time-Resolved Spectroscopy: A higher fraction of short-period binaries for metal-rich F-type dwarfs in SDSS

    CERN Document Server

    Hettinger, T; Strader, J; Bickerton, S J; Beers, T C

    2015-01-01

    Stellar multiplicity lies at the heart of many problems in modern astrophysics, including the physics of star formation, the observational properties of unresolved stellar populations, and the rates of interacting binaries such as cataclysmic variables, X-ray binaries, and Type Ia supernovae. However, little is known about the stellar multiplicity of field stars in the Milky Way, in particular about the differences in the multiplicity characteristics between metal-rich disk stars and metal-poor halo stars. In this study we perform a statistical analysis of ~15,000 F-type dwarf stars in the Milky Way through time-resolved spectroscopy with the sub-exposures archived in the Sloan Digital Sky Survey. We obtain absolute radial velocity measurements through template cross-correlation of individual sub-exposures with temporal baselines varying from minutes to years. These sparsely sampled radial velocity curves are analyzed using Markov chain Monte Carlo techniques to constrain the very short-period binary fraction...

  6. On the nature of short-period oscillations of the main Black Sea pycnocline, submesoscale eddies, and response of the marine environment to the catastrophic shower of 2012

    Science.gov (United States)

    Zatsepin, A. G.; Ostrovskii, A. G.; Kremenetskiy, V. V.; Piotukh, V. B.; Kuklev, S. B.; Moskalenko, L. V.; Podymov, O. I.; Baranov, V. I.; Korzh, A. O.; Stanichny, S. V.

    2013-11-01

    Field studies performed at the Shirshov Institute of Oceanology, Russian Academy of Sciences (SIO RAS), Black Sea hydrophysical polygon in 2012 are illustrated. The variations in the vertical distribution of the hydrophysical characteristics (water temperature, salinity, and density, as well as current velocity) in the upper 200-m layer of the Black Sea above the continental slope in the cold season, obtained using an Aqualog autonomous profiler on a moored buoy station, have been analyzed. It has been established that the position of the permanent pycno-halocline and the hydrosulphuric zone upper boundary intensively oscillate with a characteristic period of 5-10 days. These oscillations cause short-period variations in the thickness of the oxigenated layer by 20-40 m, which reaches one-third of the total thickness of the layer. Measurements performed with autonomous stations (bottom ADCP, thermochain) at the experimental subsatellite polygon in the Gelendzhik coastal zone, as well as meteorological, ship, and satellite data obtained during the catastrophic rains and flooding on July 6-7, 2012, and afterward, have been simultaneously analyzed. It has been established that a catastrophic flow of turbid fresh water into the sea caused the formation of a belt of freshened (by 1.0-2.7 psu) less dense water with a high suspension concentration on the shelf and the upper continental slope. This water formed a quasi-geostrophic northwestward along-shore current, the velocity of which reached 40-50 cm/s. Therefore, the freshened and turbid water mostly escaped from the Gelendzhik region northwestward for two days after the flood, and the remaining water became free of suspension owing to its settlement during approximately the same period. The fields of the current velocity and suspension concentration in a submesoscale cyclonic eddy, identified on the satellite image, were measured at the hydrophysical polygon. It has been established that a high (when compared to the

  7. Cirugía ambulatoria y de corta hospitalización en el cáncer de mama Ambulatory breast cancer surgery with short hospitalization period

    Directory of Open Access Journals (Sweden)

    Alexis Cantero Ronquillo

    2007-06-01

    Full Text Available La cirugía mayor ambulatoria y de corta estadía constituye un método eficaz y seguro si se hace una selección adecuada de los enfermos y se utilizan técnicas quirúrgicas depuradas con la creación consecuente de la infraestructura para tales fines. Tradicionalmente, el cáncer de mama ha requerido ingreso hospitalario por el riesgo de hemorragia posoperatoria, la necesidad del control de los drenajes quirúrgicos, etc. Internacionalmente esto ha cambiado tras la introducción de nuevas técnicas quirúrgicas como la biopsia del ganglio centinela, la estandarización de las técnicas preservadoras de tejido mamario, así como la especialización de grupos de cirugía en afecciones de la mama. La creación de un grupo de mastología en nuestro centro permitió incursionar en esta modalidad y ya podamos contar 31 pacientes operadas entre enero de 2004 y junio de 2006. Fueron utilizadas diferentes técnicas quirúrgicas con cirugía de corta estadía, previo establecimiento de los criterios de selección. Pudimos concluir que el tratamiento ambulatorio del cáncer de mama en casos seleccionados es factible, dado que se garantiza la seguridad de la paciente, la calidad asistencial y la continuidad en la atención, que además facilita la recuperación psicológica de la enferma y su reinserción temprana en la familiaAmbulatory major surgery with short hospitalization period is an efficient and safe method if a proper selection of patients is made and refined surgical techniques are used, all supported on adequate infrastructure to this end. Traditionally, breast cancer has required admission at hospital due to postsurgical hemorrhage risk, need for surgical drainage control, etc. This has changed worlwide after the introduction of new surgical techniques as sentinel node biopsy, standardization of preserving techniques for breast tissue and specialization of surgeon teams in breast illnesses. The creation of a mastology group in our center

  8. An Analysis on Probability of Extreme Drought Period from May to September in Altay Region%阿勒泰地区5—9月极端干期长度的概率特征分析

    Institute of Scientific and Technical Information of China (English)

    张林梅; 黄阿丽; 李海花; 庄晓翠

    2011-01-01

    Based on the daily precipitation data of 7 stations from1961 to 2009 in Ahay region, we calculated the continuous days without precipitation (daily precipitation less than 0.1mm) and obtained the length of extreme drought period from May to September. We analyzed its spatial distribution, change trend, and relationship with contemporaneous precipitation in the recent 49 years,estimated the parameters of distribution function by the method of probability weight (PWM), and then gave the extreme drought distribution of 50-year frequency and the probability of I〉20 d extreme drought. The results showed that the mean value and standard deviation of extreme drought period in Altay region decreased from north to south, from east to west, and the extreme dry period showed significant negative correlation with total precipitation from May to September. The trend analysis for the extreme drought period indicated that most stations (except Fuhai and Buerjin stations) shortened,especially drought of 50-year frequency and the probability north to south, from east to west. Jimunai and Fuyun. The distribution of extreme of≥20 d extreme drought both decreased from north to south, from east to west.%利用新疆阿勒泰地区7个测站1961-2009年逐日降水资料,统计5—9月连续无降水日数(日降水量〈0.1mm),得到该地区5—9月极端干期长度。分析近49a平均极端干期长度的空间分布特征、趋势变化及其与同期降水量的关系,并采用概率加权(PWM)估计其分布函数的参数,从而给出该地区50a-遇极值分布及≥20d的极端干期概率分布。结果表明:阿勒泰地区近49a极端干期长度的平均值及标准差的分布均为自北向南、自东向西递减,且极端干期与5—9月总降水量均呈显著负相关。极端干期趋势分析表明,该地区大部分站(除福海及布尔津站)呈现缩短趋势,尤其吉木乃和富蕴站通过了显著性

  9. Stable oxygen isotopic composition of corals from the Gulf of Guinea as indicators of periods of extreme precipitation conditions in the sub-Sahara

    Science.gov (United States)

    Swart, Peter K.; White, Kathy S.; Enfield, David; Dodge, Richard E.; Milne, Peter

    1998-11-01

    Stable oxygen isotopic analyses of scleractinian coral skeletons from the Gulf of Guinea in the eastern Atlantic reveal that the corals from this region can be used to identify periods of severe drought and above average precipitation in sub-Sahara Africa. Data presented in this paper show an inverse correlation between precipitation in the Sahel and the δ18O values of a coral skeletons of the species Siderastrea spp. collected from the island of Principe in the Gulf of Guinea. This is opposite to the correlation expected, as previous work has suggested that higher sea surface temperatures occur in the Gulf of Guinea during periods of low rainfall in the Sahel. Such an association would lead to a positive correlation between Sahel precipitation and skeletal δ18O. The explanation for the observed inverse correlation is that the salinity of the Gulf of Guinea is strongly influenced by the outflow from the Niger and Congo rivers. These periods of high freshwater input also correlate with periods of higher rainfall in the sub-Sahara and therefore affect the δ18O values of the coral skeleton. The correlation between δ18O values of the coral skeleton and temperature in the northern subtropical Atlantic Ocean (r = -0.34), the magnitude of the dipole (r = -0.45), and the latitudinal position of the intertropical convergence zone (r = -0.37) illustrate that the δ18O values in the coral skeleton reflect climate dynamics of the region that affect the precipitation patterns in sub-Sahara Africa.

  10. Extreme Heat

    Science.gov (United States)

    ... Landslides & Debris Flow Nuclear Blast Nuclear Power Plants Power Outages Pandemic Radiological Dispersion Device Severe Weather Snowstorms & Extreme ... Landslides & Debris Flow Nuclear Blast Nuclear Power Plants Power Outages Pandemic Radiological Dispersion Device Severe Weather Snowstorms & Extreme ...

  11. Effects of short-period exercise training and orlistat therapy on body composition and maximal power production capacity in obese patients.

    Science.gov (United States)

    Colak, R; Ozcelik, O

    2004-01-01

    We examined the effects of weight loss induced by diet-orlistat (DO) and diet-orlistat combined with exercise (DOE) on maximal work rate production (Wmax) capacity in obese patients. Total of 24 obese patients were involved in this study. Twelve of them were subjected to DO therapy only and the remaining 12 patients participated in a regular aerobic exercise-training program in addition to DO therapy (DOE). Each patient performed two incremental ramp exercise tests up to exhaustion using an electromagnetically-braked cycle ergometer: one at the onset and one at the end of the 4th week. DOE therapy caused a significant decrease in total body weight: 101.5+/-17.4 kg (basal) vs 96.3+/-17.3 kg (4 wk) associated with a significant decrease in body fat mass: 45.0+/-10.5 kg (basal) vs 40.9+/-9.8 kg (4 wk). DO therapy also resulted in a significant decrease of total body weight 94.9+/-14.9 kg (basal) vs 91.6+/-13.5 kg (4 wk) associated with small but significant decreases in body fat mass: 37.7+/-5.6 kg (basal) to 36.0+/-6.2 kg (4 wk). Weight reduction achieved during DO therapy was not associated with increased Wmax capacity: 106+/-32 W (basal) vs 106+/-33 W (4 wk), while DOE therapy resulted in a markedly increased Wmax capacity: 109+/-39 W (basal) vs 138+/-30 W (4 wk). DO therapy combined with aerobic exercise training resulted in a significant reduction of fat mass tissue and markedly improved the aerobic fitness and Wmax capacities of obese patients. Considering this improvement within such a short period, physicians should consider applying an aerobic exercise-training program to sedentary obese patients for improving their physical fitness and thereby reduce the negative outcomes of obesity.

  12. Mandelbrot's Extremism

    NARCIS (Netherlands)

    Beirlant, J.; Schoutens, W.; Segers, J.J.J.

    2004-01-01

    In the sixties Mandelbrot already showed that extreme price swings are more likely than some of us think or incorporate in our models.A modern toolbox for analyzing such rare events can be found in the field of extreme value theory.At the core of extreme value theory lies the modelling of maxima

  13. Effects of low-frequency repetitive transcranial magnetic stimulation and neuromuscular electrical stimulation on upper extremity motor recovery in the early period after stroke: a preliminary study.

    Science.gov (United States)

    Tosun, Aliye; Türe, Sabiha; Askin, Ayhan; Yardimci, Engin Ugur; Demirdal, Secil Umit; Kurt Incesu, Tülay; Tosun, Ozgur; Kocyigit, Hikmet; Akhan, Galip; Gelal, Fazıl Mustafa

    2017-07-01

    To assess the efficacy of inhibitory repetitive transcranial magnetic stimulation (rTMS) and neuromuscular electrical stimulation (NMES) on upper extremity motor function in patients with acute/subacute ischemic stroke. Twenty-five ischemic acute/subacute stroke subjects were enrolled in this randomized controlled trial. Experimental group 1 received low frequency (LF) rTMS to the primary motor cortex of the unaffected side + physical therapy (PT) including activities to improve strength, flexibility, transfers, posture, balance, coordination, and activities of daily living, mainly focusing on upper limb movements; experimental group 2 received the same protocol combined with NMES to hand extensor muscles; and the control group received only PT. Functional magnetic resonance imaging (fMRI) scan was used to evaluate the activation or inhibition of the affected and unaffected primary motor cortex. No adverse effect was reported. Most of the clinical outcome scores improved significantly in all groups, however no statistically significant difference was found between groups due to the small sample sizes. The highest percent improvement scores were observed in TMS + NMES group (varying between 48 and 99.3%) and the lowest scores in control group (varying between 13.1 and 28.1%). Hand motor recovery was significant in both experimental groups while it did not change in control group. Some motor cortex excitability changes were also observed in fMRI. LF-rTMS with or without NMES seems to facilitate the motor recovery in the paretic hand of patients with acute/subacute ischemic stroke. TMS or the combination of TMS + NMES may be a promising additional therapy in upper limb motor training. Further studies with larger numbers of patients are needed to establish their effectiveness in upper limb motor rehabilitation of stroke.

  14. Reaction dynamics. Extremely short-lived reaction resonances in Cl + HD (v = 1) → DCl + H due to chemical bond softening.

    Science.gov (United States)

    Yang, Tiangang; Chen, Jun; Huang, Long; Wang, Tao; Xiao, Chunlei; Sun, Zhigang; Dai, Dongxu; Yang, Xueming; Zhang, Dong H

    2015-01-02

    The Cl + H2 reaction is an important benchmark system in the study of chemical reaction dynamics that has always appeared to proceed via a direct abstraction mechanism, with no clear signature of reaction resonances. Here we report a high-resolution crossed-molecular beam study on the Cl + HD (v = 1, j = 0) → DCl + H reaction (where v is the vibrational quantum number and j is the rotational quantum number). Very few forward scattered products were observed. However, two distinctive peaks at collision energies of 2.4 and 4.3 kilocalories per mole for the DCl (v' = 1) product were detected in the backward scattering direction. Detailed quantum dynamics calculations on a highly accurate potential energy surface suggested that these features originate from two very short-lived dynamical resonances trapped in the peculiar H-DCl (v' = 2) vibrational adiabatic potential wells that result from chemical bond softening. We anticipate that dynamical resonances trapped in such wells exist in many reactions involving vibrationally excited molecules.

  15. Landscape genetics reveals inbreeding and genetic bottlenecks in the extremely rare short-globose cacti Mammillaria pectinifera (Cactaceae as a result of habitat fragmentation

    Directory of Open Access Journals (Sweden)

    Reyna Maya-García

    2017-02-01

    Full Text Available Mammillaria pectinifera is an endemic, short-globose cactus species, included in the IUCN list as a threatened species with only 18 remaining populations in the Tehuacán-Cuicatlán Valley in central Mexico. We evaluated the population genetic diversity and structure, connectivity, recent bottlenecks and population size, using nuclear microsatellites. M. pectinifera showed high genetic diversity but some evidence of heterozygote deficiency (FIS, recent bottlenecks in some populations and reductions in population size. Also, we found low population genetic differentiation and high values of connectivity for M. pectinifera, as the result of historical events of gene flow through pollen and seed dispersal. M. pectinifera occurs in sites with some degree of disturbance leading to the isolation of its populations and decreasing the levels of gene flow among them. Excessive deforestation also changes the original vegetation damaging the natural habitats. This species will become extinct if it is not properly preserved. Furthermore, this species has some ecological features that make them more vulnerable to disturbance such as a very low growth rates and long life cycles. We suggest in situ conservation to prevent the decrease of population sizes and loss of genetic diversity in the natural protected areas such as the Tehuacán-Cuicatlán Biosphere Reserve. In addition, a long-term ex situ conservation program is need to construct seed banks, and optimize seed germination and plant establishment protocols that restore disturbed habitats. Furthermore, creating a supply of living plants for trade is critical to avoid further extraction of plants from nature.

  16. 基于核函数极限学习机的分布式光伏短期功率预测%Distributed photovoltaic short-term power output forecasting based on extreme learning machine with kernel

    Institute of Scientific and Technical Information of China (English)

    刘念; 张清鑫; 李小芳

    2014-01-01

    Along with the rapid development of rural power network in our country, the power demand increases and creates the environment for distributed energy access to the agricultural power network. Taking integration application program with the distributed photovoltaic power output systems through the rural power network and other application forms is a realization and effective method for the new clean energy can be absorbed at local, reducing carbon emissions and environmental pollution. In our country, the national government had developed and introduced relevant policies, and making plans toward to the rapid and healthy development of distributed photovoltaic power output systems for a period of time in the near future. In addition to the national planning, the State Grid Corporation of China also proposed their policies about macro planning and access technologies, that making convenience to the legal proceedings for the personal property distributed photovoltaic access, and offering the related technical support for the distributed photovoltaic power output system access. In order to make sure the operation stability and economy of micro-grid and distribution network with the distributed photovoltaic power output systems access at rural power network, the distributed photovoltaic power output forecasting technology need to be deeply researched combining with the forecasting system application environment characteristics of the rural power network. For the distributed photovoltaic power output system at user side, a short-term PV power output forecasting method based on the algorithm that extreme learning machine with kernel (ELM_k) is proposed. This method considers the operation cost constraints of short-term power output forecasting system, such as does not depending on the high cost of numerical weather prediction. This forecasting system also considers the application characteristics of rural power network, such as the lack of professional maintenance for the

  17. Discussion on the paper "Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearest block bootstrap approach"

    Institute of Scientific and Technical Information of China (English)

    LI W.K.; LI GuoDong

    2009-01-01

    @@ The authors are to be congratulated for an innovative paper in terms of both modelling methodology and subject matter significance. The analysis of short time series is known to be difficult even for linear models.

  18. Student Teachers of Technology and Design: Can Short Periods of STEM-Related Industrial Placement Change Student Perceptions of Engineering and Technology?

    Science.gov (United States)

    Gibson, Ken S.

    2012-01-01

    This is a report, on a small-scale case study, of a programme of short industrial placements (5 day block) for student teachers of technology and design in Northern Ireland. Such placements increase student awareness and understanding of the nature of Engineering and Technology and therefore better prepare them to teach these subjects, as integral…

  19. Short-term alpha-tocopherol treatment during neonatal period modulates pro-inflammatory response to endotoxin (LPS) challenge in the same calves several months later

    Science.gov (United States)

    Vitamin E, a major natural antioxidant, has been previously shown to attenuate pro-inflammatory response to immune challenge in cattle. Our objective was to evaluate the effect of short-term treatment with alpha-tocopherol in newborn calves on selected elements of the pro-inflamatory response to LPS...

  20. Extreme cosmos

    CERN Document Server

    Gaensler, Bryan

    2011-01-01

    The universe is all about extremes. Space has a temperature 270°C below freezing. Stars die in catastrophic supernova explosions a billion times brighter than the Sun. A black hole can generate 10 million trillion volts of electricity. And hypergiants are stars 2 billion kilometres across, larger than the orbit of Jupiter. Extreme Cosmos provides a stunning new view of the way the Universe works, seen through the lens of extremes: the fastest, hottest, heaviest, brightest, oldest, densest and even the loudest. This is an astronomy book that not only offers amazing facts and figures but also re

  1. DAILY AND SHORT-PERIOD CHANGES DYNAMICS OF THE EARTH’S MAGNETIC FIELD IN THE 24-TH CYCLE OF SOLAR ACTIVITY ACCORDING TO MAGNETIC OBSERVATORY "ODESSA"

    OpenAIRE

    2013-01-01

    The Registration of Bx, By, Bz - vector components of the Earth's magnetic field, with a time resolution in 1 second is carried out on magnetic observa­tory " Odessa". . Results of calculated module of a full vector of magnetic field variations for 2008-2010 are analyzed. "The quasi-daily period" of solar dynamics is determined by wavelet analysis. The daily period and the spectra of shorter duration periods are substracted by digital filtering method. In consequence of the recieved data magn...

  2. Estimating changes in temperature extremes from millennial-scale climate simulations using generalized extreme value (GEV) distributions

    Science.gov (United States)

    Huang, Whitney K.; Stein, Michael L.; McInerney, David J.; Sun, Shanshan; Moyer, Elisabeth J.

    2016-07-01

    Changes in extreme weather may produce some of the largest societal impacts of anthropogenic climate change. However, it is intrinsically difficult to estimate changes in extreme events from the short observational record. In this work we use millennial runs from the Community Climate System Model version 3 (CCSM3) in equilibrated pre-industrial and possible future (700 and 1400 ppm CO2) conditions to examine both how extremes change in this model and how well these changes can be estimated as a function of run length. We estimate changes to distributions of future temperature extremes (annual minima and annual maxima) in the contiguous United States by fitting generalized extreme value (GEV) distributions. Using 1000-year pre-industrial and future time series, we show that warm extremes largely change in accordance with mean shifts in the distribution of summertime temperatures. Cold extremes warm more than mean shifts in the distribution of wintertime temperatures, but changes in GEV location parameters are generally well explained by the combination of mean shifts and reduced wintertime temperature variability. For cold extremes at inland locations, return levels at long recurrence intervals show additional effects related to changes in the spread and shape of GEV distributions. We then examine uncertainties that result from using shorter model runs. In theory, the GEV distribution can allow prediction of infrequent events using time series shorter than the recurrence interval of those events. To investigate how well this approach works in practice, we estimate 20-, 50-, and 100-year extreme events using segments of varying lengths. We find that even using GEV distributions, time series of comparable or shorter length than the return period of interest can lead to very poor estimates. These results suggest caution when attempting to use short observational time series or model runs to infer infrequent extremes.

  3. The Upper Limit of the Periodic Table of Elements Points out to the "Long" Version of the Table, Instead of the "Short" One

    Directory of Open Access Journals (Sweden)

    Khazan A.

    2012-01-01

    Full Text Available Herein we present an analysis of the internal constitution of the “short” and “long” forms of the Periodic Table of Elements. As a result, we conclude that the second (long version is more correct. We also suggest a long version of the Table consisting of 8 periods and 18 groups, with the last (heaviest element being element No. 155, which closes the Table.

  4. A Short-term Wind Speed Prediction Model Using Phase-space Reconstructed Extreme Learning Machine%相空间重构的极端学习机短期风速预测模型

    Institute of Scientific and Technical Information of China (English)

    武峰雨; 乐秀瑶; 南东亮

    2013-01-01

    A quick and accurate prediction of wind speed can effectively reduce or avoid the adverse effects of wind farms on power system, and can as well improve the competitiveness of the wind farm in the electricity market. In this paper, according to the chaotic characteristics of the wind speed, a short-term wind speed prediction model using phase-space reconstructed extreme learning machine (ELM) is put forward. The decision of the delay time and embedding dimension is used to reconstruct the sample space, which makes the new sample better reflect the change characteristics of wind speed. On this basis, the ELM is applied for short-term wind speed prediction. Compared with the traditional prediction model, this method has the advantages of fast learning speed and good generalization performance. Therefore, a new method is provided for wind speed prediction.%对风速进行快速、准确的预测,可以有效地减小或避免风电场对电力系统的不利影响,同时提高风电场在电力市场中的竞争能力.根据风速具有混沌特性,提出一种相空间重构的极端学习机(extreme learningmachine,ELM)的短期风速预测模型,通过确定延迟时间和嵌入维数,对样本空间进行重构,使新的样本更能反映风速变化特性,在此基础上运用ELM进行短期风速预测.与传统的预测模型相比,该方法具有学习速度快、泛化性能好等优点,为风速预测提供了新方法.

  5. Radio Flaring from the T6 Dwarf WISEPC J112254.73+255021.5 with A Possible Ultra-short Periodicity

    CERN Document Server

    Route, Matthew

    2016-01-01

    We present new results from a continuing 5 GHz search for flaring radio emission from a sample of L and T brown dwarfs, conducted with the 305-m Arecibo radio telescope. In addition to the previously reported flaring from the T6.5-dwarf 2MASS J10475385+212423, we have detected and confirmed circularly polarized flares from another T6-dwarf, WISEPC J112254.73+255021.5. Although the flares are sporadic, they appear to occur at a stable period of 0.288 hours. Given the current constraints, periods equal to its second and third subharmonic cannot be ruled out. The stability of this period over the 8-month timespan of observations indicates that, if real, it likely reflects the star's rapid rotation. If confirmed, any of the three inferred periodicities would be much shorter than the shortest, 1.41-hour rotation period of a brown dwarf measured so far. This finding would place a new observational constraint on the angular momentum evolution and rotational stability of substellar objects. The detection of radio emi...

  6. RADIO FLARING FROM THE T6 DWARF WISEPC J112254.73+255021.5 WITH A POSSIBLE ULTRA-SHORT PERIODICITY

    Energy Technology Data Exchange (ETDEWEB)

    Route, Matthew; Wolszczan, Alexander, E-mail: mroute@purdue.edu, E-mail: alex@astro.psu.edu [Department of Astronomy and Astrophysics, the Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2016-04-20

    We present new results from a continuing 5 GHz search for flaring radio emission from a sample of L and T brown dwarfs, conducted with the 305 m Arecibo radio telescope. In addition to the previously reported flaring from the T6.5 dwarf 2MASS J10475385+212423, we have detected and confirmed circularly polarized flares from another T6 dwarf, WISEPC J112254.73+255021.5. Although the flares are sporadic, they appear to occur at a stable period of 0.288 hr. Given the current constraints, periods equal to its second and third subharmonic cannot be ruled out. The stability of this period over the eight-month timespan of observations indicates that, if real, it likely reflects the star’s rapid rotation. If confirmed, any of the three inferred periodicities would be much shorter than the shortest, 1.41 hr, rotation period of a brown dwarf measured so far. This finding would place a new observational constraint on the angular momentum evolution and rotational stability of substellar objects. The detection of radio emission from the sixth ∼1000 K dwarf further demonstrates that the coolest brown dwarfs and, possibly, young giant planets, can be efficiently investigated using radio observations at centimeter wavelengths as a tool.

  7. The OmegaWhite Survey for short-period variable stars - IV. Discovery of the warm DQ white dwarf OW J175358.85-310728.9

    Science.gov (United States)

    Macfarlane, S. A.; Woudt, P. A.; Dufour, P.; Ramsay, G.; Groot, P. J.; Toma, R.; Warner, B.; Paterson, K.; Kupfer, T.; van Roestel, J.; Berdnikov, L.; Dagne, T.; Hardy, F.

    2017-09-01

    We present the discovery and follow-up observations of the second known variable warm DQ white dwarf OW J175358.85-310728.9 (OW J1753-3107). OW J1753-3107 is the brightest of any of the currently known warm or hot DQ and was discovered in the OmegaWhite Survey as exhibiting optical variations on a period of 35.5452 (2) min, with no evidence for other periods in its light curves. This period has remained constant over the last 2 yr and a single-period sinusoidal model provides a good fit for all follow-up light curves. The spectrum consists of a very blue continuum with strong absorption lines of neutral and ionized carbon, a broad He i λ4471 line and possibly weaker hydrogen lines. The C i lines are Zeeman split, and indicate the presence of a strong magnetic field. Using spectral Paschen-Back model descriptions, we determine that OW J1753-3107 exhibits the following physical parameters: Teff = 15 430 K, log (g) = 9.0, log (N(C)/N(He)) = -1.2 and the mean magnetic field strength is Bz =2.1 MG. This relatively low temperature and carbon abundance (compared to the expected properties of hot DQs) is similar to that seen in the other warm DQ SDSS J1036+6522. Although OW J1753-3107 appears to be a twin of SDSS J1036+6522, it exhibits a modulation on a period slightly longer than the dominant period in SDSS J1036+6522 and has a higher carbon abundance. The source of variations is uncertain, but they are believed to originate from the rotation of the magnetic white dwarf.

  8. Estimation of underground velocity structure using short-period microtremor array observation in Morioka area; Tanshuki bido no arei kansoku ni yoru Moriokashiiki no chika sokudo kozo no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H.; Saito, T.; Iwamoto, K. [Iwate Univ., Iwate (Japan). Faculty of Engineering; Yoshida, Y. [Oyo Corp., Tokyo (Japan); Obuchi, T. [Kawasaki Geological Engineering (Japan)

    1997-04-01

    Shallow underground velocity structure is important information on prediction of seismic characteristics of short-period component closely related to earthquake damages. Array observations of short-period microtremor were carried out at several sites in Morioka city area and the shallow underground velocity structures were estimated using frequency-wavenumber analysis and the inversion technique. At nine sites with different underground structure, the dispersion phenomena of phase velocities of Rayleigh wave with good continuity were observed and the shallow underground velocity structure were estimated from the phase velocities using two types of the inversion techniques, one for the case that unknown is S-wave velocity, and the other for the case that unknown is layer thickness. The results were consistent with those from the bore hole data. Short-period microtremor array observation has advantages of easy observation and no environmental problems and was shown to be effective for prospecting shallow underground structure beneath urban areas difficult with other geophysical prospecting techniques. 17 refs., 17 figs., 1 tab.

  9. Demonstration of a high-field short-period superconducting helical undulator suitable for future TeV-scale linear collider positron sources.

    Science.gov (United States)

    Scott, D J; Clarke, J A; Baynham, D E; Bayliss, V; Bradshaw, T; Burton, G; Brummitt, A; Carr, S; Lintern, A; Rochford, J; Taylor, O; Ivanyushenkov, Y

    2011-10-21

    The first demonstration of a full-scale working undulator module suitable for future TeV-scale positron-electron linear collider positron sources is presented. Generating sufficient positrons is an important challenge for these colliders, and using polarized e(+) would enhance the machine's capabilities. In an undulator-based source polarized positrons are generated in a metallic target via pair production initiated by circularly polarized photons produced in a helical undulator. We show how the undulator design is developed by considering impedance effects on the electron beam, modeling and constructing short prototypes before the successful fabrication, and testing of a final module.

  10. Characterization by Raman scattering, x-ray diffraction, and transmission electron microscopy of (AlAs)m(InAs)m short period superlattices grown by migration enhanced epitaxy

    DEFF Research Database (Denmark)

    Bradshaw, J.; Song, X.J.; Shealy, J.R.;

    1992-01-01

    confirm the intended periodicity and indicate the presence of some disorder in the monolayer sample. The energies of the zone folded and quantum confined optic phonons are in reasonable agreement with calculations based on one-dimensional elastic continuum and linear chain models. Journal of Applied...... Physics is copyrighted by The American Institute of Physics....

  11. Short-lived radioactive nuclides in meteorites and early solar system processes; Radioactivites eteintes a courtes periodes dans les meteorites et evolution precoce du systeme solaire

    Energy Technology Data Exchange (ETDEWEB)

    Chaussidon, M. [Centre de Recherches Petrographiques et Geochimiques, CRPG-CNRS, 54 - Vandoeuvre-les-Nancy (France); Gounelle, M. [Museum National d' Histoire Naturelle, Lab. d' Etude de la Matiere Extra-Terrestre (LEME), 75 - Paris (France)

    2007-11-15

    Now extinct, short-lived radioactive nuclides, such as {sup 7}Be (T{sub 1/2} = 53 days), {sup 10}Be (T{sub 1/2} = 1.5 Ma), {sup 26}Al (T{sub 1/2} = 0.74 Ma), {sup 36}Cl (T{sub 1/2} = 0.3 Ma), {sup 41}Ca (T{sub 1/2} = 0.1 Ma), {sup 53}Mn (T{sub 1/2} = 3.7 Ma) and {sup 60}Fe (T{sub 1/2} = 1.5 Ma), were present in the proto-solar nebula when the various components of meteorites formed. The presence of these radioactive isotopes requires a 'last-minute' origin, either nucleosynthesis in a massive star dying close in space and time to the nascent solar system or production by local irradiation of part of the proto-solar disk by high-energy solar cosmic rays. In this review, we list: (i) the different observations indicating the existence of multiple origins for short-lived radioactive nuclides, namely {sup 7}Be, {sup 10}Be and {sup 36}Cl for irradiation scenario and {sup 60}Fe for injection scenario; (ii) the constraints that exist on their distribution (homogeneous or heterogeneous) in the accretion disk; (iii) the constraints they brought on the timescales of nebular processes (from Ca-Al-rich inclusions to chondrules) and of the accretion and differentiation of planetesimals. (authors)

  12. Post-Weaning Protein Malnutrition in the Rat Produces Short and Long Term Metabolic Impairment, in Contrast to Earlier and Later Periods

    OpenAIRE

    del Carmen Miñana-Solis, María; Escobar, Carolina

    2008-01-01

    Malnutrition during gestation and lactation modifies metabolic strategies and leads to metabolic disease in adult life. Studies in human populations suggest that malnutrition during infancy may also induce long term metabolic disorders. The present study investigated if post-weaning and a late period of development might be sensitive for long term metabolic impairment. Hereto male Wistar rats were malnourished with a low protein diet (6%), during gestation and lactation (MGL), from weaning to...

  13. Production and characterisation of periodic and chirped La/B{sub 4}C-multilayer-mirrors for the reflection of ultra short XUV-pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lass, Maike; Hendel, Stefan; Bienert, Florian; Sacher, Marc D.; Hachmann, Wiebke; Heinzmann, Ulrich [Molecular and Surface Physics, Bielefeld University (Germany); Schaefers, Franz [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Elektronenspeicherring BESSY II (Germany)

    2009-07-01

    The applicability of reflective optical components for the soft X-ray region depends upon the existence of multilayer-optics. For the photon energy range of 100-190eV Lanthanum (La) is favoured as the absorber material and boroncarbide (B{sub 4}C) as the spacer material. Thin periodic and aperiodic (chirped) layer systems of those materials with double layer periods of 3.5 nm have been produced by UHV electron beam evaporation combined with ion polishing to decrease the interface roughness and thus to increase the reflectivity. In-situ layer thickness control is done by X-ray reflectometry and single-wavelength ellipsometry. The characterisation of the layer purity is done by ex-situ sputter Auger spectroscopy, whilst structural analysis is performed by X-ray diffraction, transmission electron microscopy and at-wavelength reflectivity measurements with synchrotron radiation at the BESSY II facility. We report on reflectivities of periodic and aperiodic multilayer-mirrors.

  14. A two-level perturbation method for connecting unstable periodic orbits with low fuel cost and short time of flight: application to a lunar observation mission

    Science.gov (United States)

    Tsirogiannis, George A.; Davis, Kathryn E.

    2016-07-01

    The proposed method connects two unstable periodic orbits by employing trajectories of their associated invariant manifolds that are perturbed in two levels. A first level of velocity perturbations is applied on the trajectories of the discretized manifolds at the points where they approach the nominal unstable periodic orbit in order to accelerate them. A second level of structured velocity perturbations is applied to trajectories that have already been subjected to first level perturbations in order to approximately meet the necessary conditions for a low Δ {V} transfer. Due to this two-level perturbation approach, the number of the trajectories obtained is significantly larger compared with approaches that employ traditional invariant manifolds. For this reason, the problem of connecting two unstable periodic orbits through perturbed trajectories of their manifolds is transformed into an equivalent discrete optimization problem that is solved with a very low computational complexity algorithm that is proposed in this paper. Finally, the method is applied to a lunar observation mission of practical interest and is found to perform considerably better in terms of Δ {V} cost and time of flight when compared with previous techniques applied to the same project.

  15. Short- and long-term effects of forage supplementation of calves during the preweaning period on performance, reproduction, and milk yield at first lactation.

    Science.gov (United States)

    Castells, Ll; Bach, A; Terré, M

    2015-07-01

    Sixty female Holstein calves [body weight (BW)=39.5±3.76kg] were fed a ground starter concentrate [19% crude protein, 19% neutral detergent fiber (NDF)] during the preweaning period. Furthermore, oats hay (68% NDF) was supplemented only during the postweaning period (CON) or during both pre- and postweaning periods (OH) to evaluate performance until first breeding, diet digestibility after weaning, reproductive performance, and milk yield at first lactation. Calves were individually housed and bedded with wood shavings. All calves were offered 6 L/d of milk replacer (MR) at 12% dry matter (DM) in 2 feedings until 28d of age, 3 L/d of MR at 12% DM in 2 feedings from 29 to 44d of age calves, and 1.5 L of MR at 12% DM in 1 feeding from 45 to 51d of age. Animals were weaned at 52d of age. Starter concentrate and forage intake were recorded daily and BW weekly until 65d of age. Two weeks after weaning, total-tract apparent digestibility was determined in 6 calves per treatment. Heifer BW was recorded at 10 mo of age. Breeding and milk yield at first lactation were also recorded. Starter concentrate intake was greater in OH compared with CON animals during the preweaning period. As a result, calves in the OH treatment had greater average daily gain (ADG) than CON animals during the preweaning period. After weaning, OH calves consumed more forage than CON animals, but we found no differences between treatments in ADG and starter concentrate intake. Similarly, total-tract apparent digestibility did not differ between treatments, and BW and ADG from 2wk after weaning to 10mo of age did not differ between treatments. Moreover, no differences in reproductive performance [age at first artificial insemination (AI), age at fertile insemination, conception rate at first AI, and number of AI] or milk yield at first lactation were observed between treatments, although a positive relationship between growth rate early in life and future energy-corrected milk yield was found. We

  16. Extremal almost-Kahler metrics

    CERN Document Server

    Lejmi, Mehdi

    2009-01-01

    We generalize the notion of the Futaki invariant and extremal vector field to the general almost-Kahler case and we prove the periodicity of the extremal vector field when the symplectic form represents an integral cohomology class modulo torsion. We give also an explicit formula of the hermitian scalar curvature which allows us to obtain examples of non-integrable extremal almost-Kahler metrics saturating LeBrun's estimates.

  17. Evaluation of the efficacy of a short-course, personalized self-management and intensive spa therapy intervention as active prevention of musculoskeletal disorders of the upper extremities (Muska): a research protocol for a randomized controlled trial.

    Science.gov (United States)

    Lanhers, Charlotte; Pereira, Bruno; Gay, Chloé; Hérisson, Christian; Levyckyj, Christine; Dupeyron, Arnaud; Coudeyre, Emmanuel

    2016-12-09

    Musculoskeletal disorders (MSDs) constitute a major occupational health problem in the working population, substantially impacting the quality of life of employees. They also cause considerable economic cost to the healthcare system, with, notably, the reimbursement of treatments and compensation for lost income. MSDs manifest as localized pain or functional difficulty in one or more anatomical areas, such as the cervical spine, shoulder, elbow, hand, and wrist. Although prevalence varies depending on the region considered and the method of assessment, a prevalence of 30% is found in different epidemiological studies. The disease needs to be prevented, not only for medical and economic reasons, but also for legal reasons, owing to the requirement of assessing occupational risks. The strategy envisaged may thus revolve around active, multimodal prevention that has employees fully involved at the heart of their care. Although physical exercise is widely recommended, few studies with a good level of evidence have enabled us to base a complete, well-constructed intervention on exercise that can be offered as secondary prevention in these disorders. A prospective, multicenter, comparative (intervention arm vs. control arm), randomized (immediate vs. later treatment) study using Zelen's design. This study falls under active prevention of MSDs of the upper extremities (UE-MSDs). Participants are workers aged between 18 and 65 years with latent or symptomatic MSDS, with any type of job or workstation, with or without an history of sick leave. The primary aim is to show the superiority at 3 months of a combination of spa therapy, exercise, and self-management workshops for 6 days over usual care in the management of MSDs in terms of employee functional capacity in personal and professional daily life. Secondary aims are to assess the benefit of the intervention in terms of pain, quality of life, and accumulated duration of sick leave. This randomized controlled trial is

  18. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Directory of Open Access Journals (Sweden)

    Ugur Erdemir

    2013-04-01

    Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  19. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period.

    Science.gov (United States)

    Erdemir, Ugur; Yildiz, Esra; Eren, Meltem Mert; Ozel, Sevda

    2013-01-01

    This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (pmaterials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (pmaterials were the least affected materials. The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  20. Hot subdwarf binaries from the MUCHFUSS project - Analysis of 12 new systems and a study of the short-period binary population

    CERN Document Server

    Kupfer, T; Heber, U; Østensen, R H; Barlow, B N; Maxted, P F L; Heuser, C; Schaffenroth, V; Gänsicke, B T

    2015-01-01

    The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M>1.0 M$_\\odot$), neutron stars, or stellar-mass black holes. We present orbital and atmospheric parameters and put constraints on the nature of the companions of 12 close hot subdwarf B star (sdB) binaries found in the course of the MUCHFUSS project. The systems show periods between 0.14 and 7.4 days. Three systems most likely have white dwarf companions. SDSS J083006.17+475150.3 is likely to be a rare example of a low-mass helium-core white dwarf. SDSS J095101.28+034757.0 shows an excess in the infrared that probably originates from a third companion in a wide orbit. SDSS J113241.58-063652.8 is the first helium deficient sdO star with a confirmed close companion. This study brings to 142 the number of sdB binaries with orbital periods of less than 30 days and with measured mass functions. We present an analysis of the minimu...

  1. [KINETICS OF PHOTO-INDUCED FREE RADICALS IN THE HUMAN HAIR CHESTNUT COLOR AFTER SHORT PERIODS OF RED, GREEN, BLUE AND WHITE LIGHT EXPOSURE].

    Science.gov (United States)

    Tskhvediani, N; Chikvaidze, E; Tsibadze, A; Kvachadze, I; Gogoladze, T; Katsitadze, A

    2016-04-01

    The aim of the study was to investigate the kinetics of photo-induced free radicals in the human hair chestnut color with short-term exposure to visible light in different frequency ranges. Studies carried out on human volunteers aged 17-21 years (n=37). Hairs of volunteers of the study were not treated with dyes and other active cosmetic preparations. Hairs bundled in a bun had a length - 1.5 cm, weight - 40 mg. At the beginning background EPR-spectrum of a sample was measured and then hairs were irradiated with visible light (blue, green, red and white) of different wavelength subsequently; exposure duration - 60 minutes; after the exposure the kinetics of photo-induced free radicals was measured within 60 minutes. The radiation source was selected LED array of the four crystals that provides a nearly monochromatic radiation spectrum having no parasitic infrared and ultraviolet radiations. The studies give a reason to assume that the impact on hairs by visible electromagnetic rays a leading factor is their frequency characteristics: on the one hand - the proximity of the blue light to ultraviolet radiation, and on the other - the red light to the infrared range.

  2. Grassland responses to precipitation extremes

    Science.gov (United States)

    Grassland ecosystems are naturally subjected to periods of prolonged drought and sequences of wet years. Climate change is expected to enhance the magnitude and frequency of extreme events at the intraannual and multiyear scales. Are grassland responses to extreme precipitation simply a response to ...

  3. Energy compensation in the real world: good compensation for small portions of chocolate and biscuits over short time periods in complicit consumers using commercially available foods.

    Science.gov (United States)

    Appleton, Katherine M; McKeown, Pascal P; Woodside, Jayne V

    2015-02-01

    While investigations using covert food manipulations tend to suggest that individuals are poor at adjusting for previous energy intake, in the real world adults rarely consume foods of which they are ill-informed. This study investigated the impact in fully complicit consumers of consuming commercially available dark chocolate, milk chocolate, sweet biscuits and fruit bars on subsequent appetite. Using a repeated measures design, participants received four small portions (4 × 10-11 g) of either dark chocolate, milk chocolate, sweet biscuits, fruit bars or no food throughout five separate study days (counterbalanced in order), and test meal intake, hunger, liking and acceptability were measured. Participants consumed significantly less at lunch following dark chocolate, milk chocolate and sweet biscuits compared to no food (smallest t(19) = 2.47, p = 0.02), demonstrating very good energy compensation (269-334%). No effects were found for fruit bars (t(19) = 1.76, p = 0.09), in evening meal intakes (F(4,72) = 0.62, p = 0.65) or in total intake (lunch + evening meal + food portions) (F(4,72) = 0.40, p = 0.69). No differences between conditions were found in measures of hunger (largest F(4,76) = 1.26, p = 0.29), but fruit bars were significantly less familiar than all other foods (smallest t(19) = 3.14, p = 0.01). These findings demonstrate good compensation over the short term for small portions of familiar foods in complicit consumers. Findings are most plausibly explained as a result of participant awareness and cognitions, although the nature of these cognitions cannot be discerned from this study. These findings however, also suggest that covert manipulations may have limited transfer to real world scenarios. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. 单侧全髋关节置换后遗症期的下肢步态参数%Gait parameters in lower extremities of patients in sequela period after unilateral total hip arthroplasty

    Institute of Scientific and Technical Information of China (English)

    赵江莉; 邬培慧; 徐光青; 毛玉瑢; 廖威明; 黄东锋

    2014-01-01

    BACKGROUND:Total hip arthroplasty is known to be a successful surgical procedure to al eviate hip pain and to regain gait ability, but there are many debates on whether patients’ gait could reach a normal level several years later. OBJECTIVE:To investigate spatiotemporal parameter characters of lower extremities in patients during walking in sequela period fol owing unilateral total hip arthroplasty, and to probe into patients’ walking abilities. METHODS:In accordance with the method of Case Database Data Analysis detected by Motion Reconstruction Laboratory, 14 patients at 5-10 years after total hip arthroplasty served as the experimental group, and 14 matched healthy persons served as the control group. Gait parameters of lower extremities during walking were col ected by Vicon Nexus. Spatiotemporal parameter characters of lower extremities during gait cycle were analyzed by using Polygon. RESULTS AND CONCLUSION:Compared with the control group, walking speed, cadence, stride length and step length decreased, but double support and opposite foot off increased on both affected and unaffected sides in the experimental group (P0.05). The results suggested that gaits of patients showed good gait symmetry at 5-10 years after surgery. However, they do not reach the level that observed in healthy subjects, and walking ability was poorer than normal persons. Systematic rehabilitation training is needed to improve walking ability.%背景:全髋关节置换可以为患者缓解疼痛、恢复步行功能,数年后步态是否能达到正常化仍存在争议。目的:分析单侧髋关节置换后遗症期患者平地步行中下肢的时空参数特征,探讨患者步行能力。  方法:根据运动重建实验室检测病例数据库资料分析的方法,选择全髋关节置换后5-10年的患者14例为实验组,14例相匹配的健康人为对照组。采用Vicon Nexus采集患者平地步行时下肢的步态参数,应用Polygon分析步态

  5. Short communication: Folates and vitamin B12 in colostrum and milk from dairy cows fed different energy levels during the dry period.

    Science.gov (United States)

    Duplessis, M; Mann, S; Nydam, D V; Girard, C L; Pellerin, D; Overton, T R

    2015-08-01

    This study was undertaken to evaluate folate and vitamin B12 concentrations of colostrum and milk in early lactation of dairy cows fed different levels of energy during the dry period. A total of 84 multiparous Holstein cows were assigned to one of the following dietary treatments fed as a total mixed ration 57 d before the expected calving date: (1) high-energy one-group dry cow diet [1.35 Mcal of net energy for maintenance/kg of dry matter (DM); 56% corn silage, 12% wheat straw, and 32% concentrate mix on a daily DM basis]; (2) controlled-energy one-group dry cow diet (1.14 Mcal of net energy for maintenance/kg of DM; 29% corn silage, 36% wheat straw, and 35% concentrate mix on a daily DM basis); or (3) an intermediate step-up diet (controlled-energy diet from dry off until 29 d before the expected calving date and then switching to a diet representing a 50:50 blend of the controlled- and high-energy diets from 28 d before expected calving date until parturition; 1.24 Mcal of net energy for maintenance/kg of DM). After calving, all cows were fed the same diet served as a total mixed ration (44% corn silage, 14% grass silage, and 42% concentrate mix on a daily DM basis) until 42 d in milk (DIM). Colostrum samples were taken at the first milking after parturition and milk samples were taken during the morning milking at 11 and 39±2 DIM. Colostrum from the first milking and milk yields were weighed on the day of sampling. Colostrum yield from the first milking postpartum and milk yields at 11 and 39 DIM were unaffected by treatments. Colostrum yield averaged 6.8±0.7mg at the first milking postpartum, whereas milk yields at 11 and 39 DIM were, on average, 40.3±1.5 and 48.9±1.3mg/d, respectively. Folate concentrations in colostrum and milk were not different among treatments. Folate concentration of colostrum (440.3±18.8ng/mL) was higher than folate concentration in milk at 11 (93.7±3.0ng/mL) and at 39 DIM (78.4±2.6ng/mL). Vitamin B12 concentration in colostrum

  6. The effect of a short-term training period on physiological parameters and running performance: intensity distribution versus constant- intensity exercise.

    Science.gov (United States)

    Clemente-Suárez, Vicente J; Dalamitros, Athanasios A; Nikolaidis, Pantelis T

    2016-11-04

    This study compared the effect of two training strategies differing on the weekly intensity distribution on physiological parameters and running performance in moderately trained endurance athletes. Thirty male athletes were equally divided into three groups, one following an increasing weekly aerobic intensity distribution (EXP1), one with constant weekly aerobic intensitydistribution (EXP2) and a control one, following a freely chosen program (CON). Before the training intervention, athletes performed a maximal exercise treadmill test to quantify the different zones allowing training to be controlled, based on blood lactate concentration values (BLa), over a 4- week period. Changes in exercise heart rate (HR), running velocity and rate of perceived exertion at three exercise intensities corresponding to 2.5, 4 and 8 mmol·l-1 of BLa were analyzed at three testing conditions: before (pre), after two (mid) and four weeks (post). A significant increase (p ≤ 0.05) in running velocity at the intensity of 8 mmol·l-1 in EXP1 group was revealed at mid (5.5%) and post condition (11.5%), while EXP2 group showed a significant decrease in exercise HR at 4 mmol·l-1 between pre (6.7%) and post condition (9.0%) (p ≤ 0.05). The rest of the examined variables showed only trivial changes in both experimental groups at all testing conditions (p > 0.05). In addition, no changes were observed in CON group in any of the variables tested. These results demonstrate that depending on the training goal, different intensity variation strategies should be followed to induce the desired adaptations.

  7. Extreme Photonics & Applications

    CERN Document Server

    Hall, Trevor J; Paredes, Sofia A

    2010-01-01

    "Extreme Photonics & Applications" arises from the 2008 NATO Advanced Study Institute in Laser Control & Monitoring in New Materials, Biomedicine, Environment, Security and Defense. Leading experts in the manipulation of light offered by recent advances in laser physics and nanoscience were invited to give lectures in their fields of expertise and participate in discussions on current research, applications and new directions. The sum of their contributions to this book is a primer for the state of scientific knowledge and the issues within the subject of photonics taken to the extreme frontiers: molding light at the ultra-finest scales, which represents the beginning of the end to limitations in optical science for the benefit of 21st Century technological societies. Laser light is an exquisite tool for physical and chemical research. Physicists have recently developed pulsed lasers with such short durations that one laser shot takes the time of one molecular vibration or one electron rotation in an ...

  8. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: A theoretical study of harmonic generation in a short period AlGaN/GaN superlattice induced by a terahertz field

    Science.gov (United States)

    Chen, Jun-Feng; Hao, Yue

    2009-12-01

    Based on an improved energy dispersion relation, the terahertz field induced nonlinear transport of miniband electrons in a short period AlGaN/GaN superlattice is theoretically studied in this paper with a semiclassical theory. To a short period superlattice, it is not precise enough to calculate the energy dispersion relation by just using the nearest wells in tight binding method: the next to nearest wells should be considered. The results show that the electron drift velocity is 30% lower under a dc field but 10% higher under an ac field than the traditional simple cosine model obtained from the tight binding method. The influence of the terahertz field strength and frequency on the harmonic amplitude, phase and power efficiency is calculated. The relative power efficiency of the third harmonic reaches the peak value when the dc field strength equals about three times the critical field strength and the ac field strength equals about four times the critical field strength. These results show that the AlGaN/GaN superlattice is a promising candidate to convert radiation of frequency ω to radiation of frequency 3ω or even higher.

  9. Historical changes and future projection of extreme precipitation in China

    Science.gov (United States)

    Yuan, Zhe; Yang, Zhiyong; Yan, Denghua; Yin, Jun

    2017-01-01

    Investigating changes in extreme precipitation, i.e., maximum precipitation for multiday events, is critical for flood management and risk assessment. Based on the observed daily precipitation from China's Ground Precipitation 0.5° × 0.5° Gridded Dataset (V2.0) and simulated daily precipitation from five general circulation models (GCMs) provided by The Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), extreme precipitation indices corresponding to annual maximum 1-, 3-, 15-, and 30-day precipitation across China from 1961 to 2011 and 2011 to 2050 were calculated. Relative changes in the 10-, 20-, and 50-year return period estimates, using 1-, 3-, 15-, and 30-day precipitation, are discussed to represent changes in extreme precipitation in the future. Results show that (1) the spatial distribution of annual maximum precipitation for 1, 3, 15, and 30 days is similar with that of annual precipitation. An increasing trend from the northwest to the southeast was found, with the highest values shown to be in the plain region adjacent to the mountains and coastal area; (2) Comparing the observed and simulated data, it could be seen that climate models have good simulation of 10-, 20-, and 50-year return period events. Absolute relative error is less than 30 % in 80 % in the study area; (3) Extreme precipitation in the future has an increasing trend in China. In the south, extreme precipitation associated with short duration as well as the 50-year return period will likely increase to a comparatively large degree in the future. In the north, extreme precipitation associated with long duration and the 10-year return period will likely see a large increase in the future.

  10. Short Interest and Stock Returns

    OpenAIRE

    Paul Asquith; Pathak, Parag A.; Jay R. Ritter

    2004-01-01

    Using a longer time period and both NYSE-Amex and Nasdaq stocks, this paper examines short interest and stock returns in more detail than any previous study and finds that many documented patterns are not robust. While equally weighted high short interest portfolios generally underperform, value weighted portfolios do not. In addition, there is a negative correlation between market returns and short interest over our whole period. Finally, inferences from short time periods, such as 1988-1994...

  11. Very Low-mass Stellar and Substellar Companions to Solar-like Stars from Marvels III: A Short-Period Brown Dwarf Candidate Around An Active G0Iv Subgiant

    CERN Document Server

    Ma, Bo; Barnes, Rory; Crepp, Justin R; De Lee, Nathan; Dutra-Ferreira, Leticia; Esposito, Massimiliano; Femenia, Bruno; Fleming, Scott W; Gaudi, B Scott; Ghezzi, Luan; Hebb, Leslie; Hernandez, Jonay I Gonzalez; Lee, Brian L; de Mello, G F Porto; Stassun, Keivan G; Wang, Ji; Wisniewski, John P; Agol, Eric; Bizyaev, Dmitry; Cargile, Phillip; Chang, Liang; da Costa, Luiz Nicolaci; Eastman, Jason D; Gary, Bruce; Jiang, Peng; Kane, Stephen R; Li, Rui; Liu, Jian; Mahadevan, Suvrath; Maia, Marcio A G; Muna, Demitri; Nguyen, Duy Cuong; Ogando, Ricardo L C; Oravetz, Daniel; Pepper, Joshua; Paegert, Martin; Prieto, Carlos Allende; Rebolo, Rafael; Santiago, Basilio X; Schneider, Donald P; Shelden, Alaina; Simmons, Audrey; Sivarani, Thirupathi; van Eyken, J C; Wan, Xiaoke; Weaver, Benjamin A; Zhao, Bo

    2012-01-01

    We present an eccentric, short-period brown dwarf candidate orbiting the active, slightly evolved subgiant star TYC 2087-00255-1, which has effective temperature T_eff = 5903+/-42 K, surface gravity log (g) = 4.07+/-0.16 (cgs), and metallicity [Fe/H] = -0.23+/-0.07. This candidate was discovered using data from the first two years of the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the third phase of Sloan Digital Sky Survey. From our 38 radial velocity measurements spread over a two-year time baseline, we derive a Keplerian orbital fit with semi-amplitude K=3.571+/-0.041 km/s, period P=9.0090+/-0.0004 days, and eccentricity e=0.226+/-0.011. Adopting a mass of 1.16+/-0.11 Msun for the subgiant host star, we infer that the companion has a minimum mass of 40.0+/-2.5 M_Jup. Assuming an edge-on orbit, the semimajor axis is 0.090+/-0.003 AU. The host star is photometrically variable at the \\sim1% level with a period of \\sim13.16+/-0.01 days, indicating that the host sta...

  12. Very Low-mass Stellar and Substellar Companions to Solar-like Stars from MARVELS II: A Short-period Companion Orbiting an F Star with Evidence of a Stellar Tertiary And Significant Mutual Inclination

    CERN Document Server

    Fleming, Scott W; Barnes, Rory; Beatty, Thomas G; Crepp, Justin R; De Lee, Nathan; Esposito, Massimiliano; Femenia, Bruno; Ferreira, Leticia; Gary, Bruce; Gaudi, B Scott; Ghezzi, Luan; Hernández, Jonay I González; Hebb, Leslie; Jiang, Peng; Lee, Brian; Nelson, Ben; de Mello, Gustavo F Porto; Shappee, Benjamin J; Stassun, Keivan; Thompson, Todd A; Tofflemire, Benjamin M; Wisniewski, John P; Wood-Vasey, W Michael; Agol, Eric; Prieto, Carlos Allende; Bizyaev, Dmitry; Brewington, Howard; Cargile, Phillip A; Coban, Louis; Costello, Korena S; da Costa, Luis N; Good, Melanie L; Hua, Nelson; Kane, Stephen R; Lander, Gary R; Liu, Jian; Ma, Bo; Mahadevan, Suvrath; Maia, Marcio A G; Malanushenko, Elena; Malanushenko, Viktor; Muna, Demitri; Nguyen, Duy Cuong; Oravetz, Daniel; Paegert, Martin; Pan, Kaike; Pepper, Joshua; Rebolo, Rafael; Roebuck, Eric J; Santiago, Basilio X; Schneider, Donald P; Shelden, Alaina; Simmons, Audrey; Sivarani, Thirupathi; Snedden, Stephanie; Vincent, Chelsea L M; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A; Weaver, Gwendolyn M; Zhao, Bo

    2012-01-01

    We report the discovery via radial velocity of a short-period (P = 2.430420 \\pm 0.000006 days) companion to the F-type main sequence star TYC 2930-00872-1. A long-term trend in the radial velocities indicates the presence of a tertiary stellar companion with $P > 2000$ days. High-resolution spectroscopy of the host star yields T_eff = 6427 +/- 33 K, log(g) = 4.52 +/- 0.14, and [Fe/H]=-0.04 +/- 0.05. These parameters, combined with the broad-band spectral energy distribution and parallax, allow us to infer a mass and radius of the host star of M_1=1.21 +/- 0.08 M_\\odot and R_1=1.09_{-0.13}^{+0.15} R_\\odot. We are able to exclude transits of the inner companion with high confidence. The host star's spectrum exhibits clear Ca H and K core emission indicating stellar activity, but a lack of photometric variability and small v*sin(I) suggest the primary's spin axis is oriented in a pole-on configuration. The rotational period of the primary from an activity-rotation relation matches the orbital period of the inner...

  13. Measuring risk of crude oil at extreme quantiles

    Directory of Open Access Journals (Sweden)

    Saša Žiković

    2011-06-01

    Full Text Available The purpose of this paper is to investigate the performance of VaR models at measuring risk for WTI oil one-month futures returns. Risk models, ranging from industry standards such as RiskMetrics and historical simulation to conditional extreme value model, are used to calculate commodity market risk at extreme quantiles: 0.95, 0.99, 0.995 and 0.999 for both long and short trading positions. Our results show that out of the tested fat tailed distributions, generalised Pareto distribution provides the best fit to both tails of oil returns although tails differ significantly, with the right tail having a higher tail index, indicative of more extreme events. The main conclusion is that, in the analysed period, only extreme value theory based models provide a reasonable degree of safety while widespread VaR models do not provide adequate risk coverage and their performance is especially weak for short position in oil.

  14. Do Short and Sustained Periods of American College of Rheumatology/European League Against Rheumatism Remission Predict Functional and Radiographic Outcome in Early Rheumatoid Arthritis Patients With Low Overall Damage Progression?

    Science.gov (United States)

    Konijn, Nicole P C; van Tuyl, Lilian H D; Boers, Maarten; den Uyl, Debby; Ter Wee, Marieke M; Kerstens, Pit; Voskuyl, Alexandre E; van Schaardenburg, Dirkjan; Nurmohamed, Michael T; Lems, Willem F

    2017-07-01

    To investigate whether remission at single and consecutive visits predicts good outcome in early rheumatoid arthritis (RA). The presence of remission according to American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) and other criteria (Boolean clinical, Clinical Disease Activity Index, Disease Activity Score [DAS], DAS in 28 joints, and Routine Assessment of Patient Index Data 3) was assessed in early RA patients during the first year of the Combination Therapy for Rheumatoid Arthritis light trial. Likelihood ratios were used to assess whether meeting the remission criteria at single visits (13, 26, 39, or 52 weeks) and consecutive visits (13 and 26, 26 and 39, or 39 and 52 weeks) predicted good outcome in the second year (52-104 weeks). Good outcome was defined for function (Health Assessment Questionnaire score consistently ≤0.5 and no deterioration), radiographic damage progression (no deterioration in Sharp/van der Heijde scores), and both ("overall good outcome"). Of the original 164 trial patients, 144 had evaluable data. In the second year, good functional outcome was observed in 35%, good radiographic outcome in 79%, and both in 28% of the patients. Almost all criteria predicted good functional and good overall outcome, at both single and consecutive visits; only single DAS remission did not significantly predict good overall outcome (P = 0.07). Sustained remission periods resulted in higher likelihood ratios than remission at single visits. None of the criteria predicted good radiographic outcome. Early RA patients who reached remission according to ACR/EULAR and other criteria during short or sustained periods were likely to retain good physical function in the subsequent months. Sustained remission periods were a stronger predictor than remission at single visits. However, in the setting of low overall damage progression, (sustained) remission was not predictive of good radiographic outcome. © 2016, American College of

  15. VERY-LOW-MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. III. A SHORT-PERIOD BROWN DWARF CANDIDATE AROUND AN ACTIVE G0IV SUBGIANT

    Energy Technology Data Exchange (ETDEWEB)

    Ma Bo; Ge Jian; De Lee, Nathan; Fleming, Scott W.; Lee, Brian L.; Wang Ji [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Barnes, Rory; Agol, Eric [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Dutra-Ferreira, Leticia; Porto de Mello, G. F. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira do Pedro Antonio, 43, CEP: 20080-090, Rio de Janeiro, RJ (Brazil); Esposito, Massimiliano; Femenia, Bruno; Gonzalez Hernandez, Jonay I. [Instituto de Astrofisica de Canarias, C/Via Lctea S/N, E-38200 La Laguna (Spain); Gaudi, B. Scott [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Ghezzi, Luan [Laboratorio Interinstitucional de e-Astronomia (LIneA), Rio de Janeiro, RJ 20921-400 (Brazil); Hebb, Leslie; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Wisniewski, John P. [Homer L Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks St, Norman, OK 73019 (United States); Bizyaev, Dmitry, E-mail: boma@astro.ufl.edu [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); and others

    2013-01-01

    We present an eccentric, short-period brown dwarf candidate orbiting the active, slightly evolved subgiant star TYC 2087-00255-1, which has effective temperature T{sub eff} = 5903 {+-} 42 K, surface gravity log (g) = 4.07 {+-} 0.16 (cgs), and metallicity [Fe/H] = -0.23 {+-} 0.07. This candidate was discovered using data from the first two years of the Multi-object APO Radial Velocity Exoplanets Large-area Survey, which is part of the third phase of Sloan Digital Sky Survey. From our 38 radial velocity measurements spread over a two-year time baseline, we derive a Keplerian orbital fit with semi-amplitude K = 3.571 {+-} 0.041 km s{sup -1}, period P = 9.0090 {+-} 0.0004 days, and eccentricity e = 0.226 {+-} 0.011. Adopting a mass of 1.16 {+-} 0.11 M{sub Sun} for the subgiant host star, we infer that the companion has a minimum mass of 40.0 {+-} 2.5 M{sub Jup}. Assuming an edge-on orbit, the semimajor axis is 0.090 {+-} 0.003 AU. The host star is photometrically variable at the {approx}1% level with a period of {approx}13.16 {+-} 0.01 days, indicating that the host star spin and companion orbit are not synchronized. Through adaptive optics imaging we also found a point source 643 {+-} 10 mas away from TYC 2087-00255-1, which would have a mass of 0.13 M{sub Sun} if it is physically associated with TYC 2087-00255-1 and has the same age. Future proper motion observation should be able to resolve if this tertiary object is physically associated with TYC 2087-00255-1 and make TYC 2087-00255-1 a triple body system. Core Ca II H and K line emission indicate that the host is chromospherically active, at a level that is consistent with the inferred spin period and measured v{sub rot}sin i, but unusual for a subgiant of this T{sub eff}. This activity could be explained by ongoing tidal spin-up of the host star by the companion.

  16. Very-low-mass Stellar and Substellar Companions to Solar-like Stars from Marvels. III. A Short-period Brown Dwarf Candidate around an Active G0IV Subgiant

    Science.gov (United States)

    Ma, Bo; Ge, Jian; Barnes, Rory; Crepp, Justin R.; De Lee, Nathan; Dutra-Ferreira, Leticia; Esposito, Massimiliano; Femenia, Bruno; Fleming, Scott W.; Gaudi, B. Scott; Ghezzi, Luan; Hebb, Leslie; Gonzalez Hernandez, Jonay I.; Lee, Brian L.; Porto de Mello, G. F.; Stassun, Keivan G.; Wang, Ji; Wisniewski, John P.; Agol, Eric; Bizyaev, Dmitry; Cargile, Phillip; Chang, Liang; Nicolaci da Costa, Luiz; Eastman, Jason D.; Gary, Bruce; Jiang, Peng; Kane, Stephen R.; Li, Rui; Liu, Jian; Mahadevan, Suvrath; Maia, Marcio A. G.; Muna, Demitri; Nguyen, Duy Cuong; Ogando, Ricardo L. C.; Oravetz, Daniel; Pepper, Joshua; Paegert, Martin; Allende Prieto, Carlos; Rebolo, Rafael; Santiago, Basilio X.; Schneider, Donald P.; Shelden, Alaina; Simmons, Audrey; Sivarani, Thirupathi; van Eyken, J. C.; Wan, Xiaoke; Weaver, Benjamin A.; Zhao, Bo

    2013-01-01

    We present an eccentric, short-period brown dwarf candidate orbiting the active, slightly evolved subgiant star TYC 2087-00255-1, which has effective temperature T eff = 5903 ± 42 K, surface gravity log (g) = 4.07 ± 0.16 (cgs), and metallicity [Fe/H] = -0.23 ± 0.07. This candidate was discovered using data from the first two years of the Multi-object APO Radial Velocity Exoplanets Large-area Survey, which is part of the third phase of Sloan Digital Sky Survey. From our 38 radial velocity measurements spread over a two-year time baseline, we derive a Keplerian orbital fit with semi-amplitude K = 3.571 ± 0.041 km s-1, period P = 9.0090 ± 0.0004 days, and eccentricity e = 0.226 ± 0.011. Adopting a mass of 1.16 ± 0.11 M ⊙ for the subgiant host star, we infer that the companion has a minimum mass of 40.0 ± 2.5 M Jup. Assuming an edge-on orbit, the semimajor axis is 0.090 ± 0.003 AU. The host star is photometrically variable at the ~1% level with a period of ~13.16 ± 0.01 days, indicating that the host star spin and companion orbit are not synchronized. Through adaptive optics imaging we also found a point source 643 ± 10 mas away from TYC 2087-00255-1, which would have a mass of 0.13 M ⊙ if it is physically associated with TYC 2087-00255-1 and has the same age. Future proper motion observation should be able to resolve if this tertiary object is physically associated with TYC 2087-00255-1 and make TYC 2087-00255-1 a triple body system. Core Ca II H and K line emission indicate that the host is chromospherically active, at a level that is consistent with the inferred spin period and measured v rotsin i, but unusual for a subgiant of this T eff. This activity could be explained by ongoing tidal spin-up of the host star by the companion.

  17. Effects Evaluation of Short-period Training of Delirium Related Knowledge on the ICU Nurses%对ICU护士开展谵妄知识短期培训的效果评价

    Institute of Scientific and Technical Information of China (English)

    张伟英; 顾君君; 胡文琳; 邱文娟; 叶文琴

    2014-01-01

    目的:探讨对心外科 ICU护士开展谵妄知识短期培训的效果,为完善谵妄护理干预方案提供依据.方法对心外科55名 ICU护士进行为期1周的短期培训,在培训前和培训后进行问卷调查,调查护士对谵妄知识的掌握程度;以培训时间为界将心外科冠状动脉旁路移植术(coronary artery bypass graft,CABG)患者分为培训前的 A组和培训后的 B组,比较两组患者谵妄发生率.结果培训后护士对谵妄知识的认知程度和掌握程度均有提高,B组患者术后谵妄发生率显著低于 A 组(P<0.05).结论对护士进行谵妄知识短期培训能够提高 ICU护士对谵妄知识的认知和掌握程度,降低患者谵妄发生率.%Objective To explore the effects of short-period delirium related knowledge training to the ICU nurses,and to provide evidences to improve the interventions on delirium nursing and management.Methods Totally 5 5 nurses of Cardiothoracic ICU were trained on delirium related knowledge for one week.The investigation questionnaires were conducted before and after the training to evaluate the knowledge of ICU nurses about delirium.The CABG patients were divided into before training group A and after training group B.The delirium incidence of two groups of patients were compared.Results After training,the train-ing nurses know more about delirium related knowledge,and the delirium incidence of group B was signifi-cantly decreased compared with that of group A (P<0.05).Conclusion Short-period training to the ICU nurses on delirium can help to improve the knowledge of nurses and decrease the delirium incidence of pa-tients.

  18. Office evaluation and treatment of lower extremity injuries in the runner.

    Science.gov (United States)

    Mattalino, A J; Deese, J M; Campbell, E D

    1989-07-01

    Lower extremity problems in the runner are common and often perplexing. Although many problems such as acute tendinitis and mild sprains can be treated with short periods of rest and nonsteroidal anti-inflammatory drugs, some will be chronic or recurrent in nature. These persistent problems can cause even a serious runner to reduce his activity greatly or even give up the sport entirely. Chronic recurring ailments should be examined carefully with a high suspicion of a biomechanical imbalance in the foot or lower extremity. With a basic understanding of the biomechanics of the foot and ankle and the stresses incurred during running, most of the problems can be managed conservatively.

  19. Calculation of Stator Temperature for Linear Induction Motor in Short-Time Periodic%周期暂态工作大功率直线感应电机定子温度计算

    Institute of Scientific and Technical Information of China (English)

    王智勇

    2014-01-01

    Based on the requirement of high-power linear propulsion system, the short-time periodic linear induction motor ( LIM) needs to be designed. Based on thermal network, taking into account the end-winding and the effects of thermal conduction composite materials, the calculation method of the linear induction motor temperature field was proposed. The thermal network model of the temperature field of the periodic transient LIM was deduced. The rule of the LIM coil temperature change was obtained accurately. The simulation model was established based on the mathematical model, and then the performance of the motor thermal dissipation was simulated, which provided an important reference for the design and performance analysis of the linear induction motor.%基于大功率直线推进的要求,设计短时周期工作的直线感应电机。提出了基于热网络法,计及端部绕组热传导、复合材料影响的直线电机温度场计算方法,推导了周期暂态工作的直线电机温度场热网络模型,得到了该直线电机线圈导体准确的温度变化规律。基于数学模型建立了仿真模型,对电机散热性能进行了仿真计算,为该直线感应电动机的设计和性能分析提供了重要参考。

  20. Spatial dependence of extreme rainfall

    Science.gov (United States)

    Radi, Noor Fadhilah Ahmad; Zakaria, Roslinazairimah; Satari, Siti Zanariah; Azman, Muhammad Az-zuhri

    2017-05-01

    This study aims to model the spatial extreme daily rainfall process using the max-stable model. The max-stable model is used to capture the dependence structure of spatial properties of extreme rainfall. Three models from max-stable are considered namely Smith, Schlather and Brown-Resnick models. The methods are applied on 12 selected rainfall stations in Kelantan, Malaysia. Most of the extreme rainfall data occur during wet season from October to December of 1971 to 2012. This period is chosen to assure the available data is enough to satisfy the assumption of stationarity. The dependence parameters including the range and smoothness, are estimated using composite likelihood approach. Then, the bootstrap approach is applied to generate synthetic extreme rainfall data for all models using the estimated dependence parameters. The goodness of fit between the observed extreme rainfall and the synthetic data is assessed using the composite likelihood information criterion (CLIC). Results show that Schlather model is the best followed by Brown-Resnick and Smith models based on the smallest CLIC's value. Thus, the max-stable model is suitable to be used to model extreme rainfall in Kelantan. The study on spatial dependence in extreme rainfall modelling is important to reduce the uncertainties of the point estimates for the tail index. If the spatial dependency is estimated individually, the uncertainties will be large. Furthermore, in the case of joint return level is of interest, taking into accounts the spatial dependence properties will improve the estimation process.

  1. The spatial return level of aggregated hourly extreme rainfall in Peninsular Malaysia

    Science.gov (United States)

    Shaffie, Mardhiyyah; Eli, Annazirin; Wan Zin, Wan Zawiah; Jemain, Abdul Aziz

    2015-07-01

    This paper is intended to ascertain the spatial pattern of extreme rainfall distribution in Peninsular Malaysia at several short time intervals, i.e., on hourly basis. Motivation of this research is due to historical records of extreme rainfall in Peninsular Malaysia, whereby many hydrological disasters at this region occur within a short time period. The hourly periods considered are 1, 2, 3, 6, 12, and 24 h. Many previous hydrological studies dealt with daily rainfall data; thus, this study enables comparison to be made on the estimated performances between daily and hourly rainfall data analyses so as to identify the impact of extreme rainfall at a shorter time scale. Return levels based on the time aggregate considered are also computed. Parameter estimation using L-moment method for four probability distributions, namely, the generalized extreme value (GEV), generalized logistic (GLO), generalized Pareto (GPA), and Pearson type III (PE3) distributions were conducted. Aided with the L-moment diagram test and mean square error (MSE) test, GLO was found to be the most appropriate distribution to represent the extreme rainfall data. At most time intervals (10, 50, and 100 years), the spatial patterns revealed that the rainfall distribution across the peninsula differ for 1- and 24-h extreme rainfalls. The outcomes of this study would provide additional information regarding patterns of extreme rainfall in Malaysia which may not be detected when considering only a higher time scale such as daily; thus, appropriate measures for shorter time scales of extreme rainfall can be planned. The implementation of such measures would be beneficial to the authorities to reduce the impact of any disastrous natural event.

  2. Growth kinetics and structural perfection of (InN)1/(GaN)1-20 short-period superlattices on +c-GaN template in dynamic atomic layer epitaxy

    Science.gov (United States)

    Kusakabe, Kazuhide; Hashimoto, Naoki; Itoi, Takaomi; Wang, Ke; Imai, Daichi; Yoshikawa, Akihiko

    2016-04-01

    The growth kinetics and structural perfection of (InN)1/(GaN)1-20 short-period superlattices (SPSs) were investigated with their application to ordered alloys in mind. The SPSs were grown on +c-GaN template at 650 °C by dynamic atomic layer epitaxy in conventional plasma-assisted molecular beam epitaxy. It was found that coherent structured InN/GaN SPSs could be fabricated when the thickness of the GaN barrier was 4 ML or above. Below 3 ML, the formation of SPSs was quite difficult owing to the increased strain in the SPS structure caused by the use of GaN as a template. The effective or average In composition of the (InN)1/(GaN)4 SPSs was around 10%, and the corresponding InN coverage in the ˜1 ML-thick InN wells was 50%. It was found that the effective InN coverage in ˜1 ML-thick InN wells could be varied with the growth conditions. In fact, the effective In composition could be increased up to 13.5%, i.e., the corresponding effective InN coverage was about 68%, by improving the capping/freezing speed by increasing the growth rate of the GaN barrier layer.

  3. Growth kinetics and structural perfection of (InN){sub 1}/(GaN){sub 1–20} short-period superlattices on +c-GaN template in dynamic atomic layer epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Kusakabe, Kazuhide; Hashimoto, Naoki; Wang, Ke; Imai, Daichi [Center for SMART Green Innovation Research, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Itoi, Takaomi [Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Yoshikawa, Akihiko, E-mail: yoshi@faculty.chiba-u.jp [Center for SMART Green Innovation Research, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Graduate School of Engineering, Kogakuin University, Hachioji, Tokyo 192-0015 (Japan)

    2016-04-11

    The growth kinetics and structural perfection of (InN){sub 1}/(GaN){sub 1–20} short-period superlattices (SPSs) were investigated with their application to ordered alloys in mind. The SPSs were grown on +c-GaN template at 650 °C by dynamic atomic layer epitaxy in conventional plasma-assisted molecular beam epitaxy. It was found that coherent structured InN/GaN SPSs could be fabricated when the thickness of the GaN barrier was 4 ML or above. Below 3 ML, the formation of SPSs was quite difficult owing to the increased strain in the SPS structure caused by the use of GaN as a template. The effective or average In composition of the (InN){sub 1}/(GaN){sub 4} SPSs was around 10%, and the corresponding InN coverage in the ∼1 ML-thick InN wells was 50%. It was found that the effective InN coverage in ∼1 ML-thick InN wells could be varied with the growth conditions. In fact, the effective In composition could be increased up to 13.5%, i.e., the corresponding effective InN coverage was about 68%, by improving the capping/freezing speed by increasing the growth rate of the GaN barrier layer.

  4. Extremely Preterm Birth

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Extremely Preterm Birth Home For Patients Search FAQs Extremely Preterm Birth ... Spanish FAQ173, June 2016 PDF Format Extremely Preterm Birth Pregnancy When is a baby considered “preterm” or “ ...

  5. VERY LOW MASS STELLAR AND SUBSTELLAR COMPANIONS TO SOLAR-LIKE STARS FROM MARVELS. II. A SHORT-PERIOD COMPANION ORBITING AN F STAR WITH EVIDENCE OF A STELLAR TERTIARY AND SIGNIFICANT MUTUAL INCLINATION

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Scott W.; Ge Jian; De Lee, Nathan; Jiang Peng; Lee, Brian; Nelson, Ben [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 2611-2055 (United States); Barnes, Rory [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Beatty, Thomas G.; Gaudi, B. Scott; Shappee, Benjamin J. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Crepp, Justin R. [Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Esposito, Massimiliano; Femenia, Bruno; Gonzalez Hernandez, Jonay I. [Instituto de Astrofisica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Ferreira, Leticia; Porto de Mello, Gustavo F. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira do Pedro Antonio, 43, CEP: 20080-090, Rio de Janeiro, RJ (Brazil); Gary, Bruce; Hebb, Leslie; Stassun, Keivan [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Ghezzi, Luan, E-mail: scfleming@psu.edu [Laboratorio Interinstitucional de e-Astronomia, LIneA, Rua Gal. Jose Cristino 77, Rio de Janeiro, RJ-20921-400 (Brazil); and others

    2012-09-15

    We report the discovery via radial velocity (RV) measurements of a short-period (P = 2.430420 {+-} 0.000006 days) companion to the F-type main-sequence star TYC 2930-00872-1. A long-term trend in the RV data also suggests the presence of a tertiary stellar companion with P > 2000 days. High-resolution spectroscopy of the host star yields T{sub eff} = 6427 {+-} 33 K, log g = 4.52 {+-} 0.14, and [Fe/H] = -0.04 {+-} 0.05. These parameters, combined with the broadband spectral energy distribution (SED) and a parallax, allow us to infer a mass and radius of the host star of M{sub 1} = 1.21 {+-} 0.08 M{sub Sun} and R{sub 1} = 1.09{sup +0.15}{sub -0.13} R{sub Sun }. The minimum mass of the inner companion is below the hydrogen-burning limit; however, the true mass is likely to be substantially higher. We are able to exclude transits of the inner companion with high confidence. Further, the host star spectrum exhibits a clear signature of Ca H and K core emission, indicating stellar activity, but a lack of photometric variability and small vsin I suggest that the primary's spin axis is oriented in a pole-on configuration. The rotational period of the primary estimated through an activity-rotation relation matches the orbital period of the inner companion to within 1.5 {sigma}, suggesting that the primary and inner companion are tidally locked. If the inner companion's orbital angular momentum vector is aligned with the stellar spin axis as expected through tidal evolution, then it has a stellar mass of {approx}0.3-0.4 M{sub Sun }. Direct imaging limits the existence of stellar companions to projected separations <30 AU. No set of spectral lines and no significant flux contribution to the SED from either companion are detected, which places individual upper mass limits of M{sub {l_brace}2,3{r_brace}} {approx}< 1.0 M{sub Sun }, provided they are not stellar remnants. If the tertiary is not a stellar remnant, then it likely has a mass of {approx}0.5-0.6 M{sub Sun

  6. Very Low Mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. II. A Short-period Companion Orbiting an F Star with Evidence of a Stellar Tertiary and Significant Mutual Inclination

    Science.gov (United States)

    Fleming, Scott W.; Ge, Jian; Barnes, Rory; Beatty, Thomas G.; Crepp, Justin R.; De Lee, Nathan; Esposito, Massimiliano; Femenia, Bruno; Ferreira, Leticia; Gary, Bruce; Gaudi, B. Scott; Ghezzi, Luan; González Hernández, Jonay I.; Hebb, Leslie; Jiang, Peng; Lee, Brian; Nelson, Ben; Porto de Mello, Gustavo F.; Shappee, Benjamin J.; Stassun, Keivan; Thompson, Todd A.; Tofflemire, Benjamin M.; Wisniewski, John P.; Wood-Vasey, W. Michael; Agol, Eric; Allende Prieto, Carlos; Bizyaev, Dmitry; Brewington, Howard; Cargile, Phillip A.; Coban, Louis; Costello, Korena S.; da Costa, Luis N.; Good, Melanie L.; Hua, Nelson; Kane, Stephen R.; Lander, Gary R.; Liu, Jian; Ma, Bo; Mahadevan, Suvrath; Maia, Marcio A. G.; Malanushenko, Elena; Malanushenko, Viktor; Muna, Demitri; Nguyen, Duy Cuong; Oravetz, Daniel; Paegert, Martin; Pan, Kaike; Pepper, Joshua; Rebolo, Rafael; Roebuck, Eric J.; Santiago, Basilio X.; Schneider, Donald P.; Shelden, Alaina; Simmons, Audrey; Sivarani, Thirupathi; Snedden, Stephanie; Vincent, Chelsea L. M.; Wan, Xiaoke; Wang, Ji; Weaver, Benjamin A.; Weaver, Gwendolyn M.; Zhao, Bo

    2012-09-01

    We report the discovery via radial velocity (RV) measurements of a short-period (P = 2.430420 ± 0.000006 days) companion to the F-type main-sequence star TYC 2930-00872-1. A long-term trend in the RV data also suggests the presence of a tertiary stellar companion with P > 2000 days. High-resolution spectroscopy of the host star yields T eff = 6427 ± 33 K, log g = 4.52 ± 0.14, and [Fe/H] = -0.04 ± 0.05. These parameters, combined with the broadband spectral energy distribution (SED) and a parallax, allow us to infer a mass and radius of the host star of M 1 = 1.21 ± 0.08 M ⊙ and R 1 = 1.09+0.15 - 0.13 R ⊙. The minimum mass of the inner companion is below the hydrogen-burning limit; however, the true mass is likely to be substantially higher. We are able to exclude transits of the inner companion with high confidence. Further, the host star spectrum exhibits a clear signature of Ca H and K core emission, indicating stellar activity, but a lack of photometric variability and small vsin I suggest that the primary's spin axis is oriented in a pole-on configuration. The rotational period of the primary estimated through an activity-rotation relation matches the orbital period of the inner companion to within 1.5 σ, suggesting that the primary and inner companion are tidally locked. If the inner companion's orbital angular momentum vector is aligned with the stellar spin axis as expected through tidal evolution, then it has a stellar mass of ~0.3-0.4 M ⊙. Direct imaging limits the existence of stellar companions to projected separations <30 AU. No set of spectral lines and no significant flux contribution to the SED from either companion are detected, which places individual upper mass limits of M {2, 3} <~ 1.0 M ⊙, provided they are not stellar remnants. If the tertiary is not a stellar remnant, then it likely has a mass of ~0.5-0.6 M ⊙, and its orbit is likely significantly inclined from that of the secondary, suggesting that the Kozai-Lidov mechanism

  7. Extreme Energy Events Monitoring report

    CERN Document Server

    Baimukhamedova, Nigina

    2015-01-01

    Following paper reflects the progress I made on Summer Student Program within Extreme Energy Events Monitor project I was working on. During 8 week period I managed to build a simple detector system that is capable of triggering events similar to explosions (sudden change in sound levels) and measuring approximate location of the event. Source codes are available upon request and settings described further.

  8. Generic Hurricane Extreme Seas State

    DEFF Research Database (Denmark)

    Wehmeyer, Christof; Skourup, Jesper; Frigaard, Peter

    2012-01-01

    the US east coast and the Gulf of Mexico (1851 - 2009) and Japanese east coast (1951 -2009) form the basis for Weibull extreme value analyses to determine return period respective maximum wind speeds. Unidirectional generic sea state spectra are obtained by application of the empirical models...

  9. BOLIVAR-tool for analysis and simulation of metocean extreme events

    Science.gov (United States)

    Lopatoukhin, Leonid; Boukhanovsky, Alexander

    2015-04-01

    Metocean extreme events are caused by the combination of multivariate and multiscale processes which depend from each other in different scales (due to short-term, synoptic, annual, year-to-year variability). There is no simple method for their estimation with controllable tolerance. Thus, the extreme analysis in practice is sometimes reduced to the exploration of various methods and models in respect to decreasing the uncertainty of estimates. Therefore, a researcher needs the multifaceted computational tools which cover the various branches of extreme analysis. BOLIVAR is the multi-functional computational software for the researches and engineers who explore the extreme environmental conditions to design and build offshore structures and floating objects. It contains a set of computational modules of various methods for extreme analysis, and a set of modules for the stochastic and hydrodynamic simulation of metocean processes. In this sense BOLIVAR is a Problem Solving Environment (PSE). The BOLIVAR is designed for extreme events analysis and contains a set of computational modules of IDM, AMS, POT, MENU, and SINTEF methods, and a set of modules for stochastic simulation of metocean processes in various scales. The BOLIVAR is the tool to simplify the resource-consuming computational experiments to explore the metocean extremes in univariate and multivariate cases. There are field ARMA models for short-term variability, spatial-temporal random pulse model for synoptic variability (storms and calms alteration), cyclostationare model of annual and year-to-year variability. The combination of above mentioned modules and data sources allows to estimate: omnidirectional and directional extremes (with T-years return periods); multivariate extremes (the set of parameters) and evaluation of their impacts to marine structures and floating objects; extremes of spatial-temporal fields (including the trajectory of T-years storms). An employment of concurrent methods for

  10. 极低频电磁场孕期暴露对妊娠影响研究进展%Advance of research on effect of extremely low frequency exposure in pregnant period on pregnancy

    Institute of Scientific and Technical Information of China (English)

    谭秋; 孙文均; 许正平

    2007-01-01

    极低频电磁场(extremely low frequency electromagnetic fields,ELF EMF)通常是指频率低于300Hz的电磁场。在日常的生产与生活环境中,ELF EMF主要来源于电力传输系统和各种电器设施,如高压输电线、家用电器等。随着电力的广泛应用,环境中ELF EMF的强度日益增高,在一定程度上已经威胁到人类的健康。近30年来,陆续有研究报道孕期暴露于ELF EMF可导致流产、宫内生长发育迟缓、

  11. Irrigation mitigates against heat extremes

    Science.gov (United States)

    Thiery, Wim; Fischer, Erich; Visser, Auke; Hirsch, Annette L.; Davin, Edouard L.; Lawrence, Dave; Hauser, Mathias; Seneviratne, Sonia I.

    2017-04-01

    Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use gridded observations and ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on hot extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. Finally we find that present-day irrigation is partly masking GHG-induced warming of extreme temperatures, with particularly strong effects in South Asia. Our results overall underline that irrigation substantially reduces our exposure to hot temperature extremes and highlight the need to account for irrigation in future climate projections.

  12. Multidimensional extremal dependence coefficients

    OpenAIRE

    2017-01-01

    Extreme values modeling has attracting the attention of researchers in diverse areas such as the environment, engineering, or finance. Multivariate extreme value distributions are particularly suitable to model the tails of multidimensional phenomena. The analysis of the dependence among multivariate maxima is useful to evaluate risk. Here we present new multivariate extreme value models, as well as, coefficients to assess multivariate extremal dependence.

  13. An integrated approach based on uniform quantization for the evaluation of complexity of short-term heart period variability: Application to 24 h Holter recordings in healthy and heart failure humans

    Science.gov (United States)

    Porta, A.; Faes, L.; Masé, M.; D'Addio, G.; Pinna, G. D.; Maestri, R.; Montano, N.; Furlan, R.; Guzzetti, S.; Nollo, G.; Malliani, A.

    2007-03-01

    We propose an integrated approach based on uniform quantization over a small number of levels for the evaluation and characterization of complexity of a process. This approach integrates information-domain analysis based on entropy rate, local nonlinear prediction, and pattern classification based on symbolic analysis. Normalized and non-normalized indexes quantifying complexity over short data sequences (˜300 samples) are derived. This approach provides a rule for deciding the optimal length of the patterns that may be worth considering and some suggestions about possible strategies to group patterns into a smaller number of families. The approach is applied to 24h Holter recordings of heart period variability derived from 12 normal (NO) subjects and 13 heart failure (HF) patients. We found that: (i) in NO subjects the normalized indexes suggest a larger complexity during the nighttime than during the daytime; (ii) this difference may be lost if non-normalized indexes are utilized; (iii) the circadian pattern in the normalized indexes is lost in HF patients; (iv) in HF patients the loss of the day-night variation in the normalized indexes is related to a tendency of complexity to increase during the daytime and to decrease during the nighttime; (v) the most likely length L =3 indicates that stable patterns (i.e., those with no variations) are more present during the daytime, while highly variable patterns (i.e., those with two unlike variations) are more frequent during the nighttime; (vii) during the daytime in HF patients, the percentage of highly variable patterns increases with respect to NO subjects, while during the nighttime, the percentage of patterns with one or two like variations decreases.

  14. The European Extreme Right and Religious Extremism

    Directory of Open Access Journals (Sweden)

    Jean-Yves Camus

    2007-12-01

    Full Text Available The ideology of the Extreme Right in Western Europe is rooted in Catholic fundamentalism and Counter-Revolutionary ideas. However, the Extreme Right, like all other political families, has had to adjust to an increasingly secular society. The old link between religion and the Extreme Right has thus been broken and in fact already was when Fascism overtook Europe: Fascism was secular, sometimes even anti-religious, in its essence. Although Catholic fundamentalists still retain strong positions within the apparatus of several Extreme Right parties (Front National, the vote for the Extreme Right is generally weak among regular churchgoers and strong among non-believers. In several countries, the vote for the Extreme Right is stronger among Protestant voters than among Catholics, since while Catholics may support Christian-Democratic parties, there are very few political parties linked to Protestant churches. Presently, it also seems that Paganism is becoming the dominant religious creed within the Extreme Right. In a multicultural Europe, non-Christian forms of religious fundamentalism such as Islamism also exist with ideological similarities to the Extreme Right, but this is not sufficient to categorize Islamism as a form of Fascism. Some Islamist groups seek alliances with the Extreme Right on the basis of their common dislike for Israel and the West, globalization and individual freedom of thought.

  15. Characterizing Extreme Ionospheric Storms

    Science.gov (United States)

    Sparks, L.; Komjathy, A.; Altshuler, E.

    2011-12-01

    Ionospheric storms consist of disturbances of the upper atmosphere that generate regions of enhanced electron density typically lasting several hours. Depending upon the storm magnitude, gradients in electron density can sometimes become large and highly localized. The existence of such localized, dense irregularities is a major source of positioning error for users of the Global Positioning System (GPS). Consequently, satellite-based augmentation systems have been implemented to improve the accuracy and to ensure the integrity of user position estimates derived from GPS measurements. Large-scale irregularities generally do not pose a serious threat to estimate integrity as they can be readily detected by such systems. Of greater concern, however, are highly localized irregularities that interfere with the propagation of a signal detected by a user measurement but are poorly sampled by the receivers in the system network. The most challenging conditions have been found to arise following disturbances of large magnitude that occur only rarely over the course of a solar cycle. These extremely disturbed conditions exhibit behavior distinct from moderately disturbed conditions and, hence, have been designated "extreme storms". In this paper we examine and compare the behavior of the extreme ionospheric storms of solar cycle 23 (or, more precisely, extreme storms occurring between January 1, 2000, and December 31, 2008), as represented in maps of vertical total electron content. To identify these storms, we present a robust means of quantifying the regional magnitude of an ionospheric storm. Ionospheric storms are observed frequently to occur in conjunction with magnetic storms, i.e., periods of geophysical activity as measured by magnetometers. While various geomagnetic indices, such as the disturbance storm time (Dst) and the planetary Kp index, have long been used to rank the magnitudes of distinct magnetic storms, no comparable, generally recognized index exists for

  16. Short tunnels.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1965-01-01

    Before dealing with the question of lighting short tunnels, it is necessary define what is meant by a tunnel and when it should be called 'short'. Confined to motorized road traffic the following is the most apt definition of a tunnel: every form of roofing-over a road section, irrespective of it le

  17. A calculation of acetone temperature field under extremely high heat flux within a short time%超急速温升下丙酮液池的温度场计算

    Institute of Scientific and Technical Information of China (English)

    金仁喜; 华顺芳; 刘登瀛; 张正芳

    2001-01-01

    According to the experiment and numerical simulation, the temperature field and its variation law of acetone and the tiny metal grains are studied under the transient and extremely high heat flux condition, while the platinum film resistance is overlaid with tiny metal grains or nothing. The speed of temperature rise, temperature grads and the thickness of heat layer are calculated numerically. Some stranger phenomena that are different from abnormal boiling are observed. It points out that it is easy to get higher speed of temperature rise while the platinum film is overlaid with nothing than with tiny metal grains despite of its vehemently boiling behavior.%通过实验和数值模拟计算,研究了瞬时、强热流极端条件下铂薄膜表面覆盖和不覆盖细小金属颗粒时丙酮液体和金属颗粒温度场分布及其变化规律.确定了温升速率、温度梯度和温度边界层厚度,发现了常规沸腾难以解释的现象,并指出覆盖金属颗粒后虽然沸腾极为激烈,但难以达到极高的温升速率,而不覆盖金属颗粒却容易产生爆发沸腾.

  18. 上肢深度烧伤肌皮瓣修复术35例护理体会%Flap myocutaneous flap to repair the upper extremity deep burn patients during operation period nursing points of

    Institute of Scientific and Technical Information of China (English)

    谭海燕

    2014-01-01

    目的:总结上肢深度烧伤患者采用皮瓣肌皮瓣修复围手术期护理要点。方法选取我院2012年10月-2013年10月收治的经皮瓣肌皮瓣修复上肢深度烧伤患者35例,给予其心理护理、皮肤准备、控制感染、疼痛护理、皮瓣观察与护理、功能锻炼等全面性护理。结果本组35例患者经护理后,30例Ⅰ期愈合,4例Ⅱ期愈合,1例皮瓣坏死。结论全面性护理是上肢深度烧伤皮瓣肌皮瓣修复术成功的有力保障。%Objective Explore the depth of the burn patients with upper limb muscle flap flap perioperative care points. Method Our hospital in October 2012, October 2013 received by the muscle flap flap 35 patients with upper extremity deep burn, given its psychological care, skin preparation, control infection, pain care, observation and nursing flaps, functional exercise and other comprehensive care. Results The group of 35 patients after treatment, 30 cases of healing Ⅰ,4 cases of healingⅡ,1 case of flap necrosis. Conclusion Upper limb muscle flap flap given the depth of burn patients comprehensive care, can accelerate wound healing and reduce the incidence of complications.

  19. The Latest on the Sokal Affair: Beyond Three Extremisms

    OpenAIRE

    Nicolescu, Basarab

    2006-01-01

    After a short summary of the Sokal Affair and of the point of view of Steven Weinberg, we discuss certain aspects of the scientist ideology present in the last book of Alan Sokal "Pesudoscience ans Postmodernism: Antagonists or Fellow-Travellers?", published in France. The danger of the three extremisms present in our time - relativist extremism, scientist extremism and its mirror-image, the religious extremism - is underlined. We point out also the necessity of a transdisciplinary dialogue b...

  20. Rising Precipitation Extremes across Nepal

    Directory of Open Access Journals (Sweden)

    Ramchandra Karki

    2017-01-01

    Full Text Available As a mountainous country, Nepal is most susceptible to precipitation extremes and related hazards, including severe floods, landslides and droughts that cause huge losses of life and property, impact the Himalayan environment, and hinder the socioeconomic development of the country. Given that the countrywide assessment of such extremes is still lacking, we present a comprehensive picture of prevailing precipitation extremes observed across Nepal. First, we present the spatial distribution of daily extreme precipitation indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI from 210 stations over the period of 1981–2010. Then, we analyze the temporal changes in the computed extremes from 76 stations, featuring long-term continuous records for the period of 1970–2012, by applying a non-parametric Mann−Kendall test to identify the existence of a trend and Sen’s slope method to calculate the true magnitude of this trend. Further, the local trends in precipitation extremes have been tested for their field significance over the distinct physio-geographical regions of Nepal, such as the lowlands, middle mountains and hills and high mountains in the west (WL, WM and WH, respectively, and likewise, in central (CL, CM and CH and eastern (EL, EM and EH Nepal. Our results suggest that the spatial patterns of high-intensity precipitation extremes are quite different to that of annual or monsoonal precipitation. Lowlands (Terai and Siwaliks that feature relatively low precipitation and less wet days (rainy days are exposed to high-intensity precipitation extremes. Our trend analysis suggests that the pre-monsoonal precipitation is significantly increasing over the lowlands and CH, while monsoonal precipitation is increasing in WM and CH and decreasing in CM, CL and EL. On the other hand, post-monsoonal precipitation is significantly decreasing across all of Nepal while winter precipitation is decreasing

  1. Theory of multivariate compound extreme value distribution and its application to extreme sea state prediction

    Institute of Scientific and Technical Information of China (English)

    LIU Defu; WANG Liping; PANG Liang

    2006-01-01

    In this paper, a new type of distribution,multivariate compound extreme value distribution(MCEVD), is introduced by compounding a discrete distribution with a multivariate continuous distribution of extreme sea events. In its engineering application the number over certain threshold level per year is fitting to Poisson distribution and the corresponding extreme sea events are fitting to Nested Logistic distribution, then the Poisson-Nested logistic trivariate compound extreme value distribution (PNLTCED) is proposed to predict extreme wave heights, periods and wind speeds in Yellow Sea. The new model gives more stable and reasonable predicted results.

  2. Detectors in Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Blaj, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carini, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Carron, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Haller, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hart, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hasi, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Herrmann, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kenney, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Segal, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tomada, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-06

    Free Electron Lasers opened a new window on imaging the motion of atoms and molecules. At SLAC, FEL experiments are performed at LCLS using 120Hz pulses with 1012 - 1013 photons in 10 femtoseconds (billions of times brighter than the most powerful synchrotrons). This extreme detection environment raises unique challenges, from obvious to surprising. Radiation damage is a constant threat due to accidental exposure to insufficiently attenuated beam, focused beam and formation of ice crystals reflecting the beam onto the detector. Often high power optical lasers are also used (e.g., 25TW), increasing the risk of damage or impeding data acquisition through electromagnetic pulses (EMP). The sample can contaminate the detector surface or even produce shrapnel damage. Some experiments require ultra high vacuum (UHV) with strict design, surface contamination and cooling requirements - also for detectors. The setup is often changed between or during experiments with short turnaround times, risking mechanical and ESD damage, requiring work planning, training of operators and sometimes continuous participation of the LCLS Detector Group in the experiments. The detectors used most often at LCLS are CSPAD cameras for hard x-rays and pnCCDs for soft x-rays.

  3. Applied extreme-value statistics

    Energy Technology Data Exchange (ETDEWEB)

    Kinnison, R.R.

    1983-05-01

    The statistical theory of extreme values is a well established part of theoretical statistics. Unfortunately, it is seldom part of applied statistics and is infrequently a part of statistical curricula except in advanced studies programs. This has resulted in the impression that it is difficult to understand and not of practical value. In recent environmental and pollution literature, several short articles have appeared with the purpose of documenting all that is necessary for the practical application of extreme value theory to field problems (for example, Roberts, 1979). These articles are so concise that only a statistician can recognise all the subtleties and assumptions necessary for the correct use of the material presented. The intent of this text is to expand upon several recent articles, and to provide the necessary statistical background so that the non-statistician scientist can recognize and extreme value problem when it occurs in his work, be confident in handling simple extreme value problems himself, and know when the problem is statistically beyond his capabilities and requires consultation.

  4. Short stature

    Science.gov (United States)

    ... condition. Bone or skeletal disorders, such as: Rickets Achondroplasia Chronic diseases, such as: Asthma Celiac disease Congenital ... growth seems slow or your child seems small. TREATMENT Your child's short stature may affect her self- ...

  5. Short communication

    African Journals Online (AJOL)

    preferred customer

    ABSTRACT: Nutrients, metabolizable energy (ME), anti-nutritional factors, digestible organic ... for animals are in short supply and expensive, ... peels from hotels (Hawassa); sisal waste from ..... chain omega-3 fatty acids in livestock meat and.

  6. Legacy to the extreme

    NARCIS (Netherlands)

    A. van Deursen (Arie); T. Kuipers (Tobias); L.M.F. Moonen (Leon)

    2000-01-01

    textabstractWe explore the differences between developing a system using extreme programming techniques, and maintaining a legacy system. We investigate whether applying extreme programming techniques to legacy maintenance is useful and feasible.

  7. Legacy to the extreme

    NARCIS (Netherlands)

    Deursen, A. van; Kuipers, T.; Moonen, L.M.F.

    2000-01-01

    We explore the differences between developing a system using extreme programming techniques, and maintaining a legacy system. We investigate whether applying extreme programming techniques to legacy maintenance is useful and feasible.

  8. Short-rotation plantations

    Science.gov (United States)

    Philip E. Pope; Jeffery O. Dawson

    1989-01-01

    Short-rotation plantations offer several advantages over longer, more traditional rotations. They enhance the natural productivity of better sites and of tree species with rapid juvenile growth. Returns on investment are realized in a shorter period and the risk of loss is reduced compared with long term investments. Production of wood and fiber can be maximized by...

  9. Extreme environment electronics

    CERN Document Server

    Cressler, John D

    2012-01-01

    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  10. Spatiotemporal variability of extreme temperature frequency and amplitude in China

    Science.gov (United States)

    Zhang, Yuanjie; Gao, Zhiqiu; Pan, Zaitao; Li, Dan; Huang, Xinhui

    2017-03-01

    Temperature extremes in China are examined based on daily maximum and minimum temperatures from station observations and multiple global climate models. The magnitude and frequency of extremes are expressed in terms of return values and periods, respectively, estimated by the fitted Generalized Extreme Value (GEV) distribution of annual extreme temperatures. The observations suggest that changes in temperature extremes considerably exceed changes in the respective climatological means during the past five decades, with greater amplitude of increases in cold extremes than in warm extremes. The frequency of warm (cold) extremes increases (decreases) over most areas, with an increasingly faster rate as the extremity level rises. Changes in warm extremes are more dependent on the varying shape of GEV distribution than the location shift, whereas changes in cold extremes are more closely associated with the location shift. The models simulate the overall pattern of temperature extremes during 1961-1981 reasonably well in China, but they show a smaller asymmetry between changes in warm and cold extremes primarily due to their underestimation of increases in cold extremes especially over southern China. Projections from a high emission scenario show the multi-model median change in warm and cold extremes by 2040 relative to 1971 will be 2.6 °C and 2.8 °C, respectively, with the strongest changes in cold extremes shifting southward. By 2040, warm extremes at the 1971 20-year return values would occur about every three years, while the 1971 cold extremes would occur once in > 500 years.

  11. Typologies of Extreme Longevity Myths

    OpenAIRE

    2010-01-01

    Purpose. Political, national, religious, and other motivations have led the media and even scientists to errantly accept extreme longevity claims prima facie. We describe various causes of false claims of extraordinary longevity. Design and Methods. American Social Security Death Index files for the period 1980–2009 were queried for individuals with birth and death dates yielding ages 110+ years of age. Frequency was compared to a list of age-validated supercentenarians maintained by the Ge...

  12. Deficiently Extremal Gorenstein Algebras

    Indian Academy of Sciences (India)

    Pavinder Singh

    2011-08-01

    The aim of this article is to study the homological properties of deficiently extremal Gorenstein algebras. We prove that if / is an odd deficiently extremal Gorenstein algebra with pure minimal free resolution, then the codimension of / must be odd. As an application, the structure of pure minimal free resolution of a nearly extremal Gorenstein algebra is obtained.

  13. 基于集合经验模态分解和改进极限学习机的短期风速组合预测研究%A hybrid short-term wind speed forecasting model based on ensemble empirical mode decomposition and improved extreme learning machine

    Institute of Scientific and Technical Information of China (English)

    张翌晖; 王贺; 胡志坚; 王凯; 黄东山; 宁文辉; 张承学

    2014-01-01

    This paper proposes a new short-term combination prediction model of wind speed by means of ensemble empirical mode decomposition (EEMD) and improved extreme learning machine (IELM). Firstly, wind speed series is decomposed into several components with different frequency bands by EEMD to reduce the series non-stationary. Secondly, the phase space of each component is reconstructed in order to solve the randomness and component information lost of input dimensionality se