Science.gov

Sample records for 100-ns rise time

  1. Autonomous Magnetoexplosive Generator of Megavolt, 100 NS Pulses

    NASA Astrophysics Data System (ADS)

    Gurin, V. Ye.; Kataev, V. N.; Korolev, P. V.; Kargin, V. I.; Makartsev, G. F.; Nudikov, V. N.; Pikar, A. S.; Popkov, N. F.; Saratov, A. F.

    2004-11-01

    Here we present the results of the work carried out at different stages aimed at the development of autonomous magnetocumulative generators having 100 ns megavolt pulses. This generator is meant to replace the PIRIT-01 stationary facility by a magnetocumulative energy source. Using a generator with permanent magnets as a source of initial energy and multiplying this energy by a cascade of magnetoexplosive generators allows 100 kJ of energy accumulation in a contour. The generator that has a permanent magnet does not need an additional energy source for its operation. It is convenient to operate and is always available for service. Shortening the MC generator current pulse up to 1 μs is implemented using a high-voltage explosive driven opening switch. In the first sharpening cascade, the voltage increases up to 500 kV. Further shortening of the current pulse duration up to 100 ns and the voltage rise up to 1 MV are performed using plasma opening switches according to the two-stage formation scheme. Such a scheme allows the decrease of electric field strength on the insulator surface and the use of magnetic insulation in the high-voltage section of the facility.

  2. 100 ns Z-Pinch Performance on the Inductive-Energy-Based ACE 4 Generator

    NASA Astrophysics Data System (ADS)

    Coleman, Philip; Thompson, John; Crumley, Randy; Failor, Bruce; Goodrich, Phillip; Parks, Don; Rauch, John; Song, Yuanxu; Steen, Paul; Waisman, Eduardo; Weber, Bruce; Moosman, Bryan; Qi, Niansheng; Schein, Jochen; McFarland, Mike; Campbell, Kelly; Krishnan, Mahadevan

    2000-10-01

    We report on the performance of a short implosion time ( ~100 ns) argon z-pinch using an inductive-energy-storage system. The generator, ACE 4, used a plasma opening switch (POS) to conduct for over a microsecond before driving the short implosion time 2.5 cm diameter Double Eagle gas nozzle. (Previously reported ACE 4 results used longer implosion times, 150 to over 300 ns, with z-pinch load diameters up to 14 cm.) The Double Eagle nozzle, which produces more than 20 kJ of argon K-shell radiation with a current I of almost 4 MA on Double Eagle, produced more than 6 kJ with 3 MA on ACE 4. This performance is consistent with the expected I to the 4th scaling. Pinch behavior on the two machines was quite similar in terms of zippering, pulse width and pinch diameter. As on Double Eagle, the gas flow away from the nozzle was observed to pinch best. On ACE 4, recessing the nozzle behind a wire grid cathode plane moved the high output part of the pinch down to the cathode plane. This allowed us to reduce the pinch length and load inductance, hence increasing load current and yield. Similar changes could be exploited on other gas puff loads and generators to enhance x-ray output. (Thompson, et. al., report elsewhere at this meeting on the performance of the POS and its interaction with the PRS.)

  3. Low-noise detector and amplifier design for 100 ns direct detection CO{sub 2} LIDAR receiver

    SciTech Connect

    Cafferty, M.M.; Cooke, B.J.; Laubscher, B.E.; Olivas, N.L.; Fuller, K.

    1997-06-01

    The development and test results of a prototype detector/amplifier design for a background limited, pulsed 100 ns, 10--100 kHz repetition rate LIDAR/DIAL receiver system are presented. Design objectives include near-matched filter detection of received pulse amplitude and round trip time-of-flight, and the elimination of excess correlated detector/amplifier noise for optimal pulse averaging. A novel pole-zero cancellation amplifier, coupled with a state-of-the-art SBRC (Santa Barbara Research Center) infrared detector was implemented to meet design objectives. The pole-zero cancellation amplifier utilizes a tunable, pseudo-matched filter technique to match the width of the laser pulse to the shaping time of the filter for optimal SNR performance. Low frequency correlated noise, (l/f and drift noise) is rejected through a second order high gain feedback loop. The amplifier also employs an active detector bias stage minimizing detector drift. Experimental results will be provided that demonstrate near-background limited, 100 ns pulse detection performance given a 8.5--11.5 {micro}m (300 K B.B.) radiant background, with the total noise floor spectrally white for optimal pulse averaging efficiency.

  4. Amplitude- and rise-time-compensated filters

    DOEpatents

    Nowlin, Charles H.

    1984-01-01

    An amplitude-compensated rise-time-compensated filter for a pulse time-of-occurrence (TOOC) measurement system is disclosed. The filter converts an input pulse, having the characteristics of random amplitudes and random, non-zero rise times, to a bipolar output pulse wherein the output pulse has a zero-crossing time that is independent of the rise time and amplitude of the input pulse. The filter differentiates the input pulse, along the linear leading edge of the input pulse, and subtracts therefrom a pulse fractionally proportional to the input pulse. The filter of the present invention can use discrete circuit components and avoids the use of delay lines.

  5. Short rise time intense electron beam generator

    DOEpatents

    Olson, Craig L.

    1987-01-01

    A generator for producing an intense relativistic electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  6. Short rise time intense electron beam generator

    DOEpatents

    Olson, C.L.

    1984-03-16

    A generator for producing an intense relativisitc electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  7. Mapping Rise Time Information with Down-Shift Analysis

    SciTech Connect

    Tunnell, T. W., Machorro, E. A., Diaz, A. B.

    2011-11-01

    These viewgraphs summarize the application of recent developments in digital down-shift (DDS) analysis of up converted PDV data to map out how well the PDV diagnostic would capture rise time information (mid point and rise time) in short rise time (<1 ns) shock events. The mapping supports a PDV vs VISAR challenge. The analysis concepts are new (~September FY 2011), simple, and run quickly, which makes them good tools to map out (with ~1 million Monte Carlo simulations) how well PDV captures rise time information as function of baseline velocity, rise time, velocity jump, and signal-to-noise ratios.

  8. Dynamic response of polyurea subjected to nanosecond rise-time stress waves

    NASA Astrophysics Data System (ADS)

    Youssef, George; Gupta, Vijay

    2012-08-01

    Shaped charges and explosively formed projectiles used in modern warfare can attain speeds as high as 30,000 ft/s. Impacts from these threats are expected to load the armor materials in the 10 to 100 ns timeframe. During this time, the material strains are quite limited but the strain rates are extremely high. To develop armors against such threats it is imperative to understand the dynamic constitutive behavior of materials in the tens of nanoseconds timeframe. Material behavior in this parameter space cannot be obtained by even the most sophisticated plate-impact and split-Hopkinson bar setups that exist within the high energy materials field today. This paper introduces an apparatus and a test method that are based on laser-generated stress waves to obtain such material behaviors. Although applicable to any material system, the test procedures are demonstrated on polyurea which shows unusual dynamic properties. Thin polyurea layers were deformed using laser-generated stress waves with 1-2 ns rise times and 16 ns total duration. The total strain in the samples was less than 3%. Because of the transient nature of the stress wave, the strain rate varied throughout the deformation history of the sample. A peak value of 1.1×105 s-1 was calculated. It was found that the stress-strain characteristics, determined from experimentally recorded incident and transmitted wave profiles, matched satisfactorily with those computed from a 2D wave mechanics simulation in which the polyurea was modeled as a linearly viscoelastic solid with constants derived from the quasi-static experiments. Thus, the test data conformed to the Time-Temperature Superposition (TTS) principle even at extremely high strain rates of our test. This then extends the previous observations of Zhao et al. (Mech. Time-Depend. Mater. 11:289-308, 2007) who showed the applicability of the TTS principle for polyurea in the linearly viscoelastic regime up to peak strain rates of 1200 s-1.

  9. Rise Time Measurement for Ultrafast X-Ray Pulses

    DOEpatents

    Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

    2005-04-05

    A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

  10. Rise time measurement for ultrafast X-ray pulses

    DOEpatents

    Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

    2005-04-05

    A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

  11. Functional Domain Motions in Proteins on the 1 100 ns Timescale: Comparison of Neutron Spin-Echo Spectroscopy of Phosphoglycerate Kinase with Molecular-Dynamics Simulation

    SciTech Connect

    Smolin, Nikolai; Biehl, R; Kneller, Gerald; Richter, Dieter O; Smith, Jeremy C

    2011-01-01

    Protein function often requires large-scale domain motion. An exciting new development in the experimental characterization of domain motions in proteins is the application of neutron spin-echo spectroscopy (NSE). NSE directly probes coherent (i.e., pair correlated) scattering on the 1 100 ns timescale. Here, we report on all-atom molecular-dynamics (MD) simulation of a protein, phosphoglycerate kinase, from which we calculate small-angle neutron scattering (SANS) and NSE scattering properties. The simulation-derived and experimental-solution SANS results are in excellent agreement. The contributions of translational and rotational whole-molecule diffusion to the simulation-derived NSE and potential problems in their estimation are examined. Principal component analysis identifies types of domain motion that dominate the internal motion's contribution to the NSE signal, with the largest being classic hinge bending. The associated free-energy profiles are quasiharmonic and the frictional properties correspond to highly overdamped motion. The amplitudes of the motions derived by MD are smaller than those derived from the experimental analysis, and possible reasons for this difference are discussed. The MD results confirm that a significant component of the NSE arises from internal dynamics. They also demonstrate that the combination of NSE with MD is potentially useful for determining the forms, potentials of mean force, and time dependence of functional domain motions in proteins.

  12. A note on some statistical properties of rise time parameters used in muon arrival time measurements

    NASA Technical Reports Server (NTRS)

    Vanderwalt, D. J.; Devilliers, E. J.

    1985-01-01

    Most investigations of the muon arrival time distribution in EAS during the past decade made use of parameters which can collectively be called rise time parameters. The rise time parameter T sub A/B is defined as the time taken for the integrated pulse from a detector to rise from A% to B% of its full amplitude. The use of these parameters are usually restricted to the determination of the radial dependence thereof. This radial dependence of the rise time parameters are usually taken as a signature of the particle interaction characteristics in the shower. As these parameters have a stochastic nature, it seems reasonable that one should also take notice of this aspect of the rise time parameters. A statistical approach to rise time parameters is presented.

  13. Simple sub-50-ps rise-time high voltage generator

    NASA Astrophysics Data System (ADS)

    Kekez, M. M.

    1991-12-01

    This article relates to the development of an ultrafast (nanoseconds-picoseconds time scale) compact system(s) readily applicable to the field of EMP/radiation, x-ray-induced nondestructive testing, plasma fusion (energy) experiments, bioelectromagnetic (food-drug) sterilization, drivers for x-ray preionized XeCl laser and similar applications. The present work shows that the Marx and the Pulse forming section can be integrated into a single unit. The stray capacitance present in each stage acts as a peaking capacitor. For a charging voltage per stage of <40 kV, the rise time of the output pulse is below 50 ps at 200 kV into a 100-Ω load. Work is in progress to extend the voltage amplitude to 1.6 MV while maintaining the relative pulse waveform. With a contemporary optical diagnostic technique it is believed that the present concept may achieve 1-10 ps rise-time pulses at a megavolt level in ``smart gas mixtures.'' In addition a solution for the classical peaking circuit has been obtained and presented in the Appendix.

  14. Rise-Time Distortion of Signal without Carrying Signal

    NASA Astrophysics Data System (ADS)

    Bukhman, N. S.

    2016-08-01

    The article deals with one-dimensional problem of rise-time distortion signal without carrying signal, that appears in the starting point intermittently, that is signal distortion at front edge or one of its derivative. The authors show that front edge of signal isn't distorted in case of propagation in unrestricted (including absorbing) area (amplitude of starting signal step or of one of its derivatives doesn't change) and move with the accuracy of vacuum light speed. The paper proves that it is the time interval shortage that causes signal loss with the route extension, but not the reduction of its starting amplitude, during which front edge of signal retains its starting value. The research presents new values for this time interval.

  15. Design of a 5-MA 100-ns linear-transformer-driver accelerator for wire array Z-pinch experiments

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Li, Zhenghong; Wang, Zhen; Liang, Chuan; Li, Mingjia; Qi, Jianmin; Chu, Yanyun

    2016-03-01

    The linear-transformer-driver (LTD) is a recently developed pulsed-power technology that shows great promise for a number of applications. These include a Z -pinch-driven fission-fusion-hybrid reactor that is being developed by the Chinese Academy of Engineering Physics. In support of the reactor development effort, we are planning to build an LTD-based accelerator that is optimized for driving wire-array Z -pinch loads. The accelerator comprises six modules in parallel, each of which has eight series 0.8-MA LTD cavities in a voltage-adder configuration. Vacuum transmission lines are used from the interior of the adder to the central vacuum chamber where the load is placed. Thus the traditional stack-flashover problem is eliminated. The machine is 3.2 m tall and 12 m in outer diameter including supports. A prototype cavity was built and tested for more than 6000 shots intermittently at a repetition rate of 0.1 Hz. A novel trigger, in which only one input trigger pulse is needed by utilizing an internal trigger brick, was developed and successfully verified in these shots. A full circuit modeling was conducted for the accelerator. The simulation result shows that a current pulse rising to 5.2 MA in 91 ns (10%-90%) can be delivered to the wire-array load, which is 1.5 cm in height, 1.2 cm in initial radius, and 1 mg in mass. The maximum implosion velocity of the load is 32 cm /μ s when compressed to 0.1 of the initial radius. The maximum kinetic energy is 78 kJ, which is 11.7% of the electric energy stored in the capacitors. This accelerator is supposed to enable a radiation energy efficiency of 20%-30%, providing a high efficient facility for research on the fast Z pinch and technologies for repetition-rate-operated accelerators.

  16. Effect of Current Rise-time on the Formation of Precursor Structures and Mass Ablation Rate in Cylindrical Wire Array Z-Pinches

    SciTech Connect

    Bott, S. C.; Eshaq, Y.; Ueda, U.; Haas, D. M.; Beg, F. N.; Hammer, D. A.; Kusse, B.; Greenly, J.; Shelkovenko, T. A.; Pikuz, S. A.; Blesener, I. C.; McBride, R. D.; Douglass, J. D.; Bell, K.; Knapp, P.; Chittenden, J. P.; Lebedev, S. V.; Bland, S. N.; Hall, G. N.; Suzuki, F. A.

    2009-01-21

    We present the first study to directly compare the mass ablation rates of cylindrical wire arrays as a function of the current rise-rate. Formation of the precursor column is investigated on both the MAPGIE (1 MA, 250 ns) and COBRA (1 MA, 100 ns) generators, and results are used to infer the change in the mass ablation rate induced by the rise-rate of the drive current. Laser shadowography, gated XUV imaging and x-ray diodes are used to compare the dynamical behavior both generators, and x-pinch radiography and XUV spectroscopy and provide density evolution and temperature measurements respectively. Results are compared to predictions from an analytical scaling model based on a fixed ablation rate, and the close correlation achieved suggests that the effective ablation velocity is not a strong function of the current rise rate.

  17. Abrupt rise of new machine ecology beyond human response time

    PubMed Central

    Johnson, Neil; Zhao, Guannan; Hunsader, Eric; Qi, Hong; Johnson, Nicholas; Meng, Jing; Tivnan, Brian

    2013-01-01

    Society's techno-social systems are becoming ever faster and more computer-orientated. However, far from simply generating faster versions of existing behaviour, we show that this speed-up can generate a new behavioural regime as humans lose the ability to intervene in real time. Analyzing millisecond-scale data for the world's largest and most powerful techno-social system, the global financial market, we uncover an abrupt transition to a new all-machine phase characterized by large numbers of subsecond extreme events. The proliferation of these subsecond events shows an intriguing correlation with the onset of the system-wide financial collapse in 2008. Our findings are consistent with an emerging ecology of competitive machines featuring ‘crowds' of predatory algorithms, and highlight the need for a new scientific theory of subsecond financial phenomena. PMID:24022120

  18. Coefficient of restitution dependence of intruder rise time in two-dimensional Brazil-nut effect

    NASA Astrophysics Data System (ADS)

    Kesuma, T.; Aji, D. P. Purwa; Viridi, S.; Suprijadi

    2016-04-01

    Brazil-Nut Effect (BNE) is a granular material phenomenon, where larger grains (usually known as intruder) rise to the top when the granular system vibrated. We observe a single intruder rise time of BNE phenomenon in a two-dimensional molecular dynamics simulation of hard spheres collision scheme. Some experiments have shown that some granular properties, such as size and density ratio, play an important role to determine the rise time. However, other property, such as coefficients of restitution, is considered not to have a measurable impact. We explore the intruder inelasticity dependence of the rise time by varying its coefficient of restitution. We found that the intruder rise time tends to be flat for relatively high coefficient of restitution and increases exponentially below a certain deflecting point for low coefficient of restitution. This holds for specific mass ratio.

  19. High voltage electrical amplifier having a short rise time

    DOEpatents

    Christie, David J.; Dallum, Gregory E.

    1991-01-01

    A circuit, comprising an amplifier and a transformer is disclosed that produces a high power pulse having a fast response time, and that responds to a digital control signal applied through a digital-to-analog converter. The present invention is suitable for driving a component such as an electro-optic modulator with a voltage in the kilovolt range. The circuit is stable at high frequencies and during pulse transients, and its impedance matching circuit matches the load impedance with the output impedance. The preferred embodiment comprises an input stage compatible with high-speed semiconductor components for amplifying the voltage of the input control signal, a buffer for isolating the input stage from the output stage; and a plurality of current amplifiers connected to the buffer. Each current amplifier is connected to a field effect transistor (FET), which switches a high voltage power supply to a transformer which then provides an output terminal for driving a load. The transformer comprises a plurality of transmission lines connected to the FETs and the load. The transformer changes the impedance and voltage of the output. The preferred embodiment also comprises a low voltage power supply for biasing the FETs at or near an operational voltage.

  20. Identification and discrimination of rise time: is it categorical or noncategorical?

    PubMed

    Kewley-Port, D; Pisoni, D B

    1984-04-01

    Previous studies have reported that rise time of sawtooth waveforms may be discriminated in either a categorical-like manner under some experimental conditions or according to Weber's law under other conditions. In the present experiments, rise time discrimination was examined with two experimental procedures: the traditional labeling and ABX tasks used in speech perception studies and an adaptive tracking procedure used in psychophysical studies. Rise time varied from 0 to 80 ms in 10-ms intervals for sawtooth signals of 1-s duration. Discrimination functions for subjects who simply discriminated the signals on any basis whatsoever as well as functions for subjects who practiced labeling the endpoint stimuli as " pluck " and "bow" before ABX discrimination were not categorical in the ABX task. In the adaptive tracking procedure, the Weber fraction obtained from the jnds of rise time was found to be a constant above 20-ms rise time. The results from the two discrimination paradigms were then compared by predicting a jnd for rise time from the ABX discrimination data by reference to the underlying psychometric function. Using this method of analysis, discrimination results from previous studies were shown to be quite similar to the discrimination results observed in this study. Taken together the results demonstrate clearly that rise time discrimination of sawtooth signals follows predictions derived from Weber's law.

  1. Dependence of current rise time on laser-triggered discharge plasma

    NASA Astrophysics Data System (ADS)

    Lim, Soowon; Kamohara, Takashi; Hosseini, S. Hamid R.; Katsuki, Sunao

    2016-07-01

    A powerful, stable extreme ultraviolet (EUV) source is the most important component for EUV lithography and EUV mask inspection. Here, we investigate the characteristics of laser-triggered discharge plasma at three different current rise times, fast, middle and slow. A height-adjustable coaxial birdcage was used to change circuit inductance. The rise time was varied between 30 ns-55 ns with peak current of 10 kA. The time-integrated EUV (at 13.5 nm in 2% bandwidth) intensity for the fast rise time was found to be 55% stronger than that of the slow rise time despite its lower energy. A high-speed Mach-Zehnder interferogram and visible imaging of the pinch plasma were employed to discuss plasma compression processes qualitatively and quantitatively. Also discharge produced debris was investigated using a silicon-crystal witness plate. The fast rise current was found to have advantages such as lower debris, higher EUV intensity, and possibility of suppressing instability in comparison with the slow rise time. As expected, total debris amounts lessened proportionally to the primary charged energy, as found from a comparison of fast and slow rise currents.

  2. Effects of Resistivity and Viscosity on m =0 Rise and Fall Time in the RFP

    NASA Astrophysics Data System (ADS)

    Futch, A. M.; Craig, D.; Hesse, R.; Jacobson, C. M.

    2016-10-01

    In the reversed field pinch (RFP), poloidal mode number m =0 fluctuations are driven in a sawtooth cycle via nonlinear coupling with unstable m =1 tearing modes. We explore how the rise and fall time of these m =0 fluctuations depends on resistivity and viscosity in visco-resistive MHD simulations using the DEBS code. Both the Lundquist number (S) and magnetic Prandtl number (Pr) affect the rise/fall time. Analysis of MST experimental data also shows that both the rise and fall times of the m =0 amplitude vary with S. The variation observed in experiment is consistent with simulation results for rise time, but shows some differences for fall time. Rise time is insensitive to the resistivity profile but depends slightly on the viscosity profile. Fall time is strongly correlated with the duration of the crash which depends on both resistivity and viscosity profiles. These results suggest that the rise and fall time of the m =0 modes at the sawtooth crash is not strongly influenced by the local resistivity near the resonant surface but instead is primarily determined by the overall dynamics of the entire sawtooth cycle. The role of viscosity is less clear though the edge viscosity affects the m =0 evolution more than the core. This work has been supported by the U.S.D.O.E.

  3. Influence of voltage rise time on microwave generation in relativistic backward wave oscillator

    SciTech Connect

    Wu, Ping; Deng, Yuqun; Sun, Jun; Teng, Yan; Shi, Yanchao; Chen, Changhua

    2015-10-15

    In relativistic backward wave oscillators (RBWOs), although the slow wave structure (SWS) and electron beam determine the main characteristics of beam-wave interaction, many other factors can also significantly affect the microwave generation process. This paper investigates the influence of voltage rise time on beam-wave interaction in RBWOs. Preliminary analysis and PIC simulations demonstrate if the voltage rise time is moderately long, the microwave frequency will gradually increase during the startup process until the voltage reaches its amplitude, which can be explained by the dispersion relation. However, if the voltage rise time is long enough, the longitudinal resonance of the finitely-long SWS will force the RBWO to work with unwanted longitudinal modes for a while and then gradually hop to the wanted longitudinal mode, and this will lead to an impure microwave frequency spectrum. Besides, a longer voltage rise time will delay the startup process and thus lead to a longer microwave saturation time. And if unwanted longitudinal modes are excited due to long voltage rise time, the microwave saturation time will be further lengthened. Therefore, the voltage rise time of accelerators adopted in high power microwave technology should not be too long in case unwanted longitudinal modes are excited.

  4. Effect of unequal rise and fall times on the autocorrelation function of a PN sequence

    NASA Astrophysics Data System (ADS)

    Churchill, F. E.

    1990-10-01

    The rise and fall times of a pseudo-noise (PN) waveform are of concern in a short-range, CW radar such as a missile fuze radar. An inequality creates a spurious pair of sidelobes and a spiky ripple on the sidelobes of the autocorrelation function, which may cause false alarms in the radar. Analytical expressions are presented which relate the spurious responses of the autocorrelation function to the waveform rise and fall times.

  5. The role of interplanetary shock orientation on SC/SI rise time and geoeffectiveness

    NASA Astrophysics Data System (ADS)

    Selvakumaran, R.; Veenadhari, B.; Ebihara, Y.; Kumar, Sandeep; Prasad, D. S. V. V. D.

    2017-03-01

    Interplanetary (IP) shocks interact with the Earth's magnetosphere, resulting in compression of the magnetosphere which in turn increases the Earth's magnetic field termed as Sudden commencement/Sudden impulse (SC/SI). Apart from IP shock speed and solar wind dynamic pressure, IP shock orientation angle also plays a major role in deciding the SC rise time. In the present study, the IP shock orientation angle and SC/SI rise time for 179 IP shocks are estimated which occurred during solar cycle 23. More than 50% of the Shock orientations are in the range of 140°-160°. The SC/SI rise time decreases with the increase in the orientation angle and IP shock speed. In this work, the type of IP shocks i.e., Radio loud (RL) and Radio quiet (RQ) are examined in connection with SC/SI rise time. The RL associated IP shock speeds show a better correlation than RQ shocks with SC/SI rise time irrespective of the orientation angle. Magnetic Cloud (MC) associated shocks dominate in producing less rise time when compared to Ejecta (EJ) shocks. Magneto hydrodynamic (MHD) simulations are used for three different IP shock orientation categories to see the importance of orientation angle in determining the geoeffectiveness. Simulations results reveal that shocks hitting parallel to the magnetosphere are more geoeffective as compared to oblique shocks by means of change in magnetic field, pressure and Field Aligned Current (FAC).

  6. CONSTRAINING PHYSICAL PROPERTIES OF TYPE IIn SUPERNOVAE THROUGH RISE TIMES AND PEAK LUMINOSITIES

    SciTech Connect

    Moriya, Takashi J.; Maeda, Keiichi

    2014-08-01

    We investigate the diversity in the wind density, supernova ejecta energy, and ejecta mass in Type IIn supernovae based on their rise times and peak luminosities. We show that the wind density and supernova ejecta properties can be estimated independently if both the rise time and peak luminosity are observed. The peak luminosity is mostly determined by the supernova properties and the rise time can be used to estimate the wind density. We find that the ejecta energies of Type IIn supernovae need to vary by factors of 0.2-5 from the average if their ejecta masses are similar. The diversity in the observed rise times indicates that their wind densities vary by factors of 0.2-2 from the average. We show that Type IIn superluminous supernovae should have not only large wind density but also large ejecta energy and/or small ejecta mass to explain their large luminosities and the rise times at the same time. We also note that shock breakout does not necessarily occur in the wind even if it is optically thick, except for the case of superluminous supernovae, and we analyze the observational data both with and without assuming that the shock breakout occurs in the dense wind of Type IIn supernovae.

  7. Rise time perception in children with reading and combined reading and language difficulties.

    PubMed

    Beattie, Rachel L; Manis, Franklin R

    2013-01-01

    Using a non-speech-specific measure of prosody, rise time perception, Goswami and her colleagues have found that individuals with dyslexia perform significantly worse than nonimpaired readers. Studies have also found that children and adults with specific language impairment were impaired on these tasks. Despite the high comorbidity of these disorders, only one study has assessed rise time sensitivity in children with comorbid reading and oral language difficulties. The authors further examined rise time sensitivity in children with both reading and oral language difficulties. They compared performance on rise time perception tasks between 18 children with reading difficulties, 15 children with combined reading and oral language difficulties, and 17 chronological age-matched controls. The authors found a significant interaction between group and performance on auditory tasks. Further tests revealed that chronological age-matched controls were significantly better on the rise time measures compared to both groups of children with reading difficulties. Performance between the groups of children with reading difficulties did not significantly differ.

  8. Rise Time of the Simulated VERITAS 12 m Davies-Cotton Reflector

    SciTech Connect

    White, Richard J.

    2005-02-21

    The Very Energetic Radiation Imaging Telescope Array System (VERITAS) will utilise Imaging Atmospheric Cherenkov Telescopes (IACTs) based on a Davies-Cotton design with f-number f/1.0 to detect cosmic gamma-rays. Unlike a parabolic reflector, light from the Davies-Cotton does not arrive isochronously at the camera. Here the effect of the telescope geometry on signal rise-time is examined. An almost square-pulse arrival time profile with a rise time of 1.7 ns is found analytically and confirmed through simulation.

  9. Transistorized Marx bank pulse circuit provides voltage multiplication with nanosecond rise-time

    NASA Technical Reports Server (NTRS)

    Jung, E. A.; Lewis, R. N.

    1968-01-01

    Base-triggered avalanche transistor circuit used in a Marx bank pulser configuration provides voltage multiplication with nanosecond rise-time. The avalanche-mode transistors replace conventional spark gaps in the Marx bank. The delay time from an input signal to the output signal to the output is typically 6 nanoseconds.

  10. Rise Time. Operational Control Tests for Wastewater Treatment Facilities. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Carnegie, John W.

    The rise time test (along with the settleometer procedure) is used to monitor sludge behavior in the secondary clarifier of an activated sludge system. The test monitors the effect of the nitrification/denitrification process and aids the operator in determining optimum clarifier sludge detention time and, to some extent, optimum degree of…

  11. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) responses elicited by bursts of white noise were recorded from the scalps of human subjects. Response alterations produced by changes in the noise burst duration (on-time), inter-burst interval (off-time), and onset and offset shapes were analyzed. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increases in stimulus duration, and therefore in loudness, resulted in a systematic increase in latency. This was probably due to response recovery processes, since the effect was eliminated with increases in stimulus off-time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It was concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  12. Extremum seeking-based optimization of high voltage converter modulator rise-time

    SciTech Connect

    Scheinker, Alexander; Bland, Michael; Krstic, Miroslav; Audia, Jeff

    2013-02-01

    We digitally implement an extremum seeking (ES) algorithm, which optimizes the rise time of the output voltage of a high voltage converter modulator (HVCM) at the Los Alamos Neutron Science Center (LANSCE) HVCM test stand by iteratively, simultaneously tuning the first 8 switching edges of each of the three phase drive waveforms (24 variables total). We achieve a 50 μs rise time, which is reduction in half compared to the 100 μs achieved at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Considering that HVCMs typically operate with an output voltage of 100 kV, with a 60Hz repetition rate, the 50 μs rise time reduction will result in very significant energy savings. The ES algorithm will prove successful, despite the noisy measurements and cost calculations, confirming the theoretical results that the algorithm is not affected by noise whose frequency components are independent of the perturbing frequencies.

  13. Discriminating cosmic muons and X-rays based on rise time using a GEM detector

    NASA Astrophysics Data System (ADS)

    Wu, Hui-Yin; Zhao, Sheng-Ying; Wang, Xiao-Dong; Zhang, Xian-Ming; Qi, Hui-Rong; Zhang, Wei; Wu, Ke-Yan; Hu, Bi-Tao; Zhang, Yi

    2016-08-01

    Gas electron multiplier (GEM) detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold. Supported by National Natural Science Foundation of China (11135002, 11275235, 11405077, 11575073)

  14. Rise-Time of FRET-Acceptor Fluorescence Tracks Protein Folding

    PubMed Central

    Lindhoud, Simon; Westphal, Adrie H.; van Mierlo, Carlo P. M.; Visser, Antonie J. W. G.; Borst, Jan Willem

    2014-01-01

    Uniform labeling of proteins with fluorescent donor and acceptor dyes with an equimolar ratio is paramount for accurate determination of Förster resonance energy transfer (FRET) efficiencies. In practice, however, the labeled protein population contains donor-labeled molecules that have no corresponding acceptor. These FRET-inactive donors contaminate the donor fluorescence signal, which leads to underestimation of FRET efficiencies in conventional fluorescence intensity and lifetime-based FRET experiments. Such contamination is avoided if FRET efficiencies are extracted from the rise time of acceptor fluorescence upon donor excitation. The reciprocal value of the rise time of acceptor fluorescence is equal to the decay rate of the FRET-active donor fluorescence. Here, we have determined rise times of sensitized acceptor fluorescence to study the folding of double-labeled apoflavodoxin molecules and show that this approach tracks the characteristics of apoflavodoxinʼs complex folding pathway. PMID:25535076

  15. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  16. DOI Determination by Rise Time Discrimination in Single-Ended Readout for TOF PET Imaging

    PubMed Central

    Wiener, R.I.; Surti, S.; Karp, J.S.

    2013-01-01

    Clinical TOF PET systems achieve detection efficiency using thick crystals, typically of thickness 2–3cm. The resulting dispersion in interaction depths degrades spatial resolution for increasing radial positions due to parallax error. Furthermore, interaction depth dispersion results in time pickoff dispersion and thus in degraded timing resolution, and is therefore of added concern in TOF scanners. Using fast signal digitization, we characterize the timing performance, pulse shape and light output of LaBr3:Ce, CeBr3 and LYSO. Coincidence timing resolution is shown to degrade by ~50ps/cm for scintillator pixels of constant cross section and increasing length. By controlling irradiation depth in a scintillator pixel, we show that DOI-dependence of time pickoff is a significant factor in the loss of timing performance in thick detectors. Using the correlated DOI-dependence of time pickoff and charge collection, we apply a charge-based correction to the time pickoff, obtaining improved coincidence timing resolution of <200ps for a uniform 4×4×30mm3 LaBr3 pixel. In order to obtain both DOI identification and improved timing resolution, we design a two layer LaBr3[5%Ce]/LaBr3[30%Ce] detector of total size 4×4×30mm3, exploiting the dependence of scintillator rise time on [Ce] in LaBr3:Ce. Using signal rise time to determine interaction layer, excellent interaction layer discrimination is achieved, while maintaining coincidence timing resolution of <250ps and energy resolution <7% using a R4998 PMT. Excellent layer separation and timing performance is measured with several other commercially-available TOF photodetectors, demonstrating the practicality of this design. These results indicate the feasibility of rise time discrimination as a technique for measuring event DOI while maintaining sensitivity, timing and energy performance, in a well-known detector architecture. PMID:24403611

  17. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    SciTech Connect

    TROYER, G.L.

    2000-08-25

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% {at} 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse rise time versus photo peak position and resolution. These data were collected to investigate the effect of pulse rise time compensation on resolution and efficiency.

  18. Effect of air on energy and rise-time spectra measured by proportional gas counter

    SciTech Connect

    Kawano, T.; Tanaka, M.; Isozumi, S.; Isozumi, Y.; Tosaki, M.; Sugiyama, T.

    2015-03-15

    Air exerts a negative effect on radiation detection using a gas counter because oxygen contained in air has a high electron attachment coefficient and can trap electrons from electron-ion pairs created by ionization from incident radiation in counting gas. This reduces radiation counts. The present study examined the influence of air on energy and rise-time spectra measurements using a proportional gas counter. In addition, a decompression procedure method was proposed to reduce the influence of air and its effectiveness was investigated. For the decompression procedure, the counting gas inside the gas counter was decompressed below atmospheric pressure before radiation detection. For the spectrum measurement, methane as well as various methane and air mixtures were used as the counting gas to determine the effect of air on energy and rise-time spectra. Results showed that the decompression procedure was effective for reducing or eliminating the influence of air on spectra measurement using a proportional gas counter. (authors)

  19. Fast Rise Time and High Voltage Nanosecond Pulses at High Pulse Repetition Frequency

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth E.; Ziemba, Timothy; Prager, James; Picard, Julian; Hashim, Akel

    2015-09-01

    Eagle Harbor Technologies (EHT), Inc. is conducting research to decrease the rise time and increase the output voltage of the EHT Nanosecond Pulser product line, which allows for independently, user-adjustable output voltage (0 - 20 kV), pulse width (20 - 500 ns), and pulse repetition frequency (0 - 100 kHz). The goals are to develop higher voltage pulses (50 - 60 kV), decrease the rise time from 20 to below 10 ns, and maintain the high pulse repetition capabilities. These new capabilities have applications to pseudospark generation, corona production, liquid discharges, and nonlinear transmission line driving for microwave production. This work is supported in part by the US Navy SBIR program.

  20. Extremum seeking-based optimization of high voltage converter modulator rise-time

    DOE PAGES

    Scheinker, Alexander; Bland, Michael; Krstic, Miroslav; ...

    2013-02-01

    We digitally implement an extremum seeking (ES) algorithm, which optimizes the rise time of the output voltage of a high voltage converter modulator (HVCM) at the Los Alamos Neutron Science Center (LANSCE) HVCM test stand by iteratively, simultaneously tuning the first 8 switching edges of each of the three phase drive waveforms (24 variables total). We achieve a 50 μs rise time, which is reduction in half compared to the 100 μs achieved at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. Considering that HVCMs typically operate with an output voltage of 100 kV, with a 60Hz repetitionmore » rate, the 50 μs rise time reduction will result in very significant energy savings. The ES algorithm will prove successful, despite the noisy measurements and cost calculations, confirming the theoretical results that the algorithm is not affected by noise whose frequency components are independent of the perturbing frequencies.« less

  1. Effect of stratification and geometrical spreading on sonic boom rise time

    NASA Technical Reports Server (NTRS)

    Cleveland, Robin O.; Hamilton, Mark F.; Blackstock, David T.

    1994-01-01

    The purpose of our investigation is to determine the effect of unsteadiness (not associated with turbulence) on rise time. The unsteadiness considered here is due to (1) geometrical spreading, (2) stratification, which includes variation in density, temperature, and relative humidity, and (3) N shaped waveform. A very general Burgers equation, which includes all these effects, is the propagation model for our study. The equation is solved by a new computational algorithm in which all the calculations are done in the time domain. The present paper is a progress report in which some of the factors contributing to unsteadiness are studied, namely geometrical spreading and variation in relative humidity. The work of Pierce and Kang, which motivated our study, is first reviewed. We proceed with a discussion of the Burgers equation model and the algorithm for solving the equation. Some comparison tests to establish the validity of the algorithm are presented. The algorithm is then used to determine the distance required for a steady-state shock, on encountering an abrupt change in relative humidity, to reach a new steady state based on the new humidity. It is found that the transition distance for plane shocks of amplitude 70 Pa is about 4 km when the change in relative humidity is 10 percent. Shocks of amplitude 140 Pa require less distance. The effect of spherical and cylindrical spreading is also considered. We demonstrate that a spreading shock wave never reaches steady state and that its rise time will be less than the equivalent steady state shock. Finally we show that an N wave has a slightly shorter rise time than a step shock of the same amplitude.

  2. CHARACTERISTICS OF A FAST RISE TIME POWER SUPPLY FOR A PULSED PLASMA REACTOR FOR CHEMICAL VAPOR DESTRUCTION

    EPA Science Inventory

    Rotating spark gap devices for switching high-voltage direct current (dc) into a corona plasma reactor can achieve pulse rise times in the range of tens of nanoseconds. The fast rise times lead to vigorous plasma generation without sparking at instantaneous applied voltages highe...

  3. Subjective response to sonic booms having different shapes, rise times, and durations

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.

    1994-01-01

    Two laboratory experiments were conducted to quantify the subjective response of people to simulated outdoor sonic booms having different pressure signatures. The specific objectives of the experiments were to compare subjective response to sonic booms when described in terms of 'loudness' and 'annoyance'; to determine the ability of various noise metrics to predict subjective response to sonic booms; to determine the effects on subjective response of rise time, duration, and level; and to compare the subjective response to 'N-wave' sonic boom signatures with the subjective response to 'minimized' sonic boom signatures. The experiments were conducted in a computer-controlled, man-rated sonic boom simulator capable of reproducing user-specified pressure signatures for a wide range of sonic boom parameters. One hundred and fifty sonic booms representing different combinations of two wave shapes, four rise times, seven durations, and three peak overpressures were presented to 36 test subjects in each experiment. The test subjects in the first experiment made judgments of 'loudness' while the test subjects in the second experiment judged 'annoyance.' Subjective response to sonic booms was the same whether expressed in terms of loudness or in terms of annoyance. Analyses of several different noise metrics indicated that A-weighted sound exposure level and Perceived Level were the best predictors of subjective response. Further analyses indicated that, of these two noise metrics, only Perceived Level completely accounted for the effects of wave shape, rise time, and peak overpressure. Neither metric fully accounted for the effect of duration. However, the magnitude of the duration effect was small over the very wide range of durations considered.

  4. Rise time of inverted triangular prism intruder in vibrating granular bed: Experiments and model

    NASA Astrophysics Data System (ADS)

    Nuraini, N.; Adriani, I. K.; Baladram, M. S.; Viridi, S.

    2012-05-01

    Experiment results and a qualitative model of the phenomenon called Brazil nut effect (BNE) with inverted triangular prism are reported in this work. The model is constructed by considering some forces (earth gravitational force, buoyant force, and fluid viscous force) and using Newton's second law of motion. The rise time of BNE T is defined as time needed for the intruder to be on granular surface with all of his parts (no part is still immersed in the granular bed). One side of the triangular base of the intruder l is varied from 1.5 to 5 cm with other two sides are kept in constant values (1 and 3 cm). It has been observed in experiment that l with value 3-4 cm gives the smaller rise time. Plot of T versus l has the form of concave up parabolic curve with minimum lies at l between 3-4 cm. This observation has been confirmed by the proposed model with the same order of magnitude and similar curve trend.

  5. Time-resolved temperature rise in a thin liquid film due to laser absorption.

    PubMed

    Cordero, María Luisa; Verneuil, Emilie; Gallaire, François; Baroud, Charles N

    2009-01-01

    The temperature increase of a thin water layer is investigated, both experimentally and numerically, when the layer is heated by an infrared laser. The laser is focused to a waist of 5.3 microm inside a 28 microm gap that contains fluorescent aqueous solutions between two glass slides. Temperature fields are measured using the temperature sensitivity of rhodamine-B, while correcting for thermal diffusion using rhodamine-101, which is insensitive to temperature. In the steady state, the shape of the hot region is well fitted with a Lorentzian function whose width ranges between 15 and 30 microm , increasing with laser power. At the same time, the maximum temperature rise ranges between 10 and 55 degrees C and can display a decrease at high laser powers. The total energy stored in the sample increases linearly with the laser power. The dynamics of the heating occurs with two distinct time scales: (i) a fast time ( tau_{Theta} = 4.2 ms in our case) which is the time taken to reach the maximum temperature at the laser position and the maximum temperature gradient, and (ii) a slow time scale for the spatial profile to reach its final width. The temperature field obtained numerically agrees quantitatively with the experiments for low laser powers but overpredicts the temperature rise while underpredicting the profile width for high powers. The total energy shows good agreement between experiments and simulations for all laser powers, suggesting that the discrepancies are due to a broadening of the laser, possibly due to a thermal lensing effect.

  6. Moon Rise

    NASA Video Gallery

    Aboard the International Space Station in May 2012, Expedition 31 astronaut Don Pettit opened the shutters covering the cupola observation windows in time to watch the moon rise. The time-lapse sce...

  7. High-Voltage Power Supply With Fast Rise and Fall Times

    NASA Technical Reports Server (NTRS)

    Bearden, Douglas B.; Acker, Richard M.; Kapuslka, Robert E.

    2007-01-01

    A special-purpose high-voltage power supply can be electronically switched on and off with fast rise and fall times, respectively. The output potential is programmable from 20 to 1,250 V. An output current of 50 A can be sustained at 1,250 V. The power supply was designed specifically for electronically shuttering a microchannel plate in an x-ray detector that must operate with exposure times as short as 1 ms. The basic design of the power supply is also adaptable to other applications in which there are requirements for rapid slewing of high voltages. The power-supply circuitry (see figure) includes a preregulator, which is used to program the output at 1/30 of the desired output potential. After the desired voltage has been set, the outputs of a pulse width modulator (PWM) are enabled and used to amplify the preregulator output potential by 30. The amplification is achieved by use of two voltage doublers with a transformer that has two primary and two secondary windings. A resistor is used to limit the current by controlling the drive voltage of two field-effect transistors (FETs) during turn-on of the PWM. A pulse transformer is used to turn on four FETs to short-circuit four output capacitors when the outputs of the PWM have been disabled. The most notable aspects of the performance of the power supply are a rise time of only 80 s and a fall time of only 60 s at a load current of 50 A or less. Another notable aspect is that the application of a 0-to-5-V square wave to a shutdown pin of the PWM causes the production of a 0-to-1,250-V square wave at the output terminals.

  8. A hybrid model for simulation of secondary electron emission in plasma immersion ion implantation under different pulse rise time

    SciTech Connect

    Navab Safa, N. Ghomi, H.

    2015-02-15

    A hybrid fluid Particle in Cell–Monte Carlo Collision (PiC–MCC) model is presented to study the effect of secondary electron emission on the plasma immersion ion implantation process under different pulse rise time. The model describes the temporal evolution of various parameters of plasma such as ion density, ion velocity, secondary electron density, and secondary electron current for different rise times. A 3D–3 V PiC–MCC model is developed to simulate the secondary electrons which are emitted from the sample surface while the plasma ions and electrons are treated using a 1D fluid model. The simulation results indicate that the secondary electron density and secondary electron current increase as the rise time decreases. The main differences between the results for different rise times are found during the initial phase of the pulse. The results are explained through studying the fundamental parameters of plasma.

  9. SN 2008iy: an unusual Type IIn Supernova with an enduring 400-d rise time

    NASA Astrophysics Data System (ADS)

    Miller, A. A.; Silverman, J. M.; Butler, N. R.; Bloom, J. S.; Chornock, R.; Filippenko, A. V.; Ganeshalingam, M.; Klein, C. R.; Li, W.; Nugent, P. E.; Smith, N.; Steele, T. N.

    2010-05-01

    We present spectroscopic and photometric observations of the Type IIn supernova (SN) 2008iy. SN 2008iy showed an unprecedentedly long rise time of ~400 d, making it the first known SN to take significantly longer than 100 d to reach peak optical luminosity. The peak absolute magnitude of SN 2008iy was Mr ~ -19.1 mag, and the total radiated energy over the first ~700 d was ~2 × 1050 erg. Spectroscopically, SN 2008iy is very similar to the Type IIn SN 1988Z at late times and, like SN 1988Z, it is a luminous X-ray source (both SNe had an X-ray luminosity LX > 1041 ergs-1). SN 2008iy has a growing near-infrared excess at late times similar to several other SNe IIn. The Hα emission-line profile of SN 2008iy shows a narrow P Cygni absorption component, implying a pre-SN wind speed of ~100kms-1. We argue that the luminosity of SN 2008iy is powered via the interaction of the SN ejecta with a dense, clumpy circumstellar medium. The ~400-d rise time can be understood if the number density of clumps increases with distance over a radius ~1.7 × 1016cm from the progenitor. This scenario is possible if the progenitor experienced an episodic phase of enhanced mass loss <1 century prior to explosion or if the progenitor wind speed increased during the decades before core collapse. We favour the former scenario, which is reminiscent of the eruptive mass-loss episodes observed for luminous blue variable (LBV) stars. The progenitor wind speed and increased mass-loss rates serve as further evidence that at least some, and perhaps all, Type IIn SNe experience LBV-like eruptions shortly before core collapse. We also discuss the host galaxy of SN 2008iy, a subluminous dwarf galaxy, and offer a few reasons why the recent suggestion that unusual, luminous SNe preferentially occur in dwarf galaxies may be the result of observational biases.

  10. Timed Rise from Floor as a Predictor of Disease Progression in Duchenne Muscular Dystrophy: An Observational Study

    PubMed Central

    Mazzone, Elena S.; Coratti, Giorgia; Sormani, Maria Pia; Messina, Sonia; Pane, Marika; D'Amico, Adele; Colia, Giulia; Fanelli, Lavinia; Berardinelli, Angela; Gardani, Alice; Lanzillotta, Valentina; D’Ambrosio, Paola; Petillo, Roberta; Cavallaro, Filippo; Frosini, Silvia; Bello, Luca; Bonfiglio, Serena; De Sanctis, Roberto; Rolle, Enrica; Forcina, Nicola; Magri, Francesca; Vita, Gianluca; Palermo, Concetta; Donati, Maria Alice; Procopio, Elena; Arnoldi, Maria Teresa; Baranello, Giovanni; Mongini, Tiziana; Pini, Antonella; Battini, Roberta; Pegoraro, Elena; Torrente, Yvan; Previtali, Stefano C.; Bruno, Claudio; Politano, Luisa; Comi, Giacomo P.; D’Angelo, Maria Grazia; Bertini, Enrico; Mercuri, Eugenio

    2016-01-01

    Background The role of timed items, and more specifically, of the time to rise from the floor, has been reported as an early prognostic factor for disease progression and loss of ambulation. The aim of our study was to investigate the possible effect of the time to rise from the floor test on the changes observed on the 6MWT over 12 months in a cohort of ambulant Duchenne boys. Subjects and methods A total of 487 12-month data points were collected from 215 ambulant Duchenne boys. The age ranged between 5.0 and 20.0 years (mean 8.48 ±2.48 DS). Results The results of the time to rise from the floor at baseline ranged from 1.2 to 29.4 seconds in the boys who could perform the test. 49 patients were unable to perform the test at baseline and 87 at 12 month The 6MWT values ranged from 82 to 567 meters at baseline. 3 patients lost the ability to perform the 6mwt at 12 months. The correlation between time to rise from the floor and 6MWT at baseline was high (r = 0.6, p<0.01). Conclusions Both time to rise from the floor and baseline 6MWT were relevant for predicting 6MWT changes in the group above the age of 7 years, with no interaction between the two measures, as the impact of time to rise from the floor on 6MWT change was similar in the patients below and above 350 m. Our results suggest that, time to rise from the floor can be considered an additional important prognostic factor of 12 month changes on the 6MWT and, more generally, of disease progression. PMID:26982196

  11. Magnitude and timing of episodic sea-level rise during the last deglaciation

    USGS Publications Warehouse

    Locker, S.D.; Hine, A.C.; Tedesco, L.P.; Shinn, E.A.

    1996-01-01

    A succession of elevated ridge deposits on the south Florida margin was mapped using high-resolution seismic and side-scan sonar imaging in water depths ranging from 50 to 124 m. The ridges are interpreted to be subtidal shoal complexes and paleoshorelines (eolian dune or beach) formed during the last sea-level transgression. Oolitic and skeletal grainstones and mixed skeletal-peloidal-ooid packstones were recovered using a research submersible. All of the grains are of shallow-water or intertidal origin, and both marine and nonmarine cements were identified. Formation and preservation of these features are attributed to episodic and rapid changes in the rate of the deglacial sea-level rise at the onset of the termination 1A ??18O excursion. This high-resolution record of sea-level change appears to be related to deglacial processes operating on submillennial time scales and supports increasing evidence of rapid episodic fluctuations in ice volume, climate, and ocean-circulation patterns during glacialinterglacial transitions.

  12. Considerations for human exposure standards for fast-rise-time high-peak-power electromagnetic pulses.

    PubMed

    Merritt, J H; Kiel, J L; Hurt, W D

    1995-06-01

    Development of new emitter systems capable of producing high-peak-power electromagnetic pulses with very fast rise times and narrow pulse widths is continuing. Such directed energy weapons systems will be used in the future to defeat electronically vulnerable targets. Human exposures to these pulses can be expected during testing and operations. Development of these technologies for radar and communications purposes has the potential for wider environmental exposure, as well. Current IEEE C95.1-1991 human exposure guidelines do not specifically address these types of pulses, though limits are stated for pulsed emissions. The process for developing standards includes an evaluation of the relevant bioeffects data base. A recommendation has been made that human exposure to ultrashort electromagnetic pulses that engender electromagnetic transients, called precursor waves, should be avoided. Studies that purport to show the potential for tissue damage induced by such pulses were described. The studies cited in support of the recommendation were not relevant to the issues of tissue damage by propagated pulses. A number of investigations are cited in this review that directly address the biological effects of electromagnetic pulses. These studies have not shown evidence of tissue damage as a result of exposure to high-peak-power pulsed microwaves. It is our opinion that the current guidelines are sufficiently protective for human exposure to these pulses.

  13. A 200 kV fast rise time, low jitter, trigger system with magnetic pulse sharpener

    SciTech Connect

    Jaitly, N.C.; Coleman, M.D.; Ramrus, A.; Earley, L.M.; Downing, J.N.; Reisch, H.H.; Caudill, L.D.; Eversol, S.A.

    1992-09-01

    The DARHT Facility is being designed at Los Alamos national Laboratory to produce high resolution flash radiographs of hydrodynamic experiments. Two linear induction accelerators (LIA), each in the range of 16 to 20 MeV, will be used to produce intense bremsstrahlung X-ray pulses of short duration (60 ns flat top). Each LIA will produce a 3 kA, high brightness, electron beam using a 4 MeV injector and a series of 250 kV induction cells. Technology demonstration of key accelerator subsystems is under progress at the DARHT Integrated Test Stand (ITS). The eight inductions cells present in the ITS are driven by a Maxwell prototype Induction Cell Pulsed Power supply (ICPPS) which provides 250 kV, 70 ns pulses via four Blumieins. Each Blumiein drives two cells and is triggered using independently controlled trigger units. This turnkey DARHT Trigger System, consisting of four separate trigger units, provides 200 kV trigger pulses with low jitter and fast rise time to each of the four Blumiein coaxial spark gaps. Details of the trigger system design and results obtained during extensive testing at Maxwell are described.

  14. Diversity of Decline-Rate-Corrected Type 1a Supernova Rise times:One Mode or Two?

    SciTech Connect

    Strovink, Mark

    2007-05-01

    B-band light-curve rise times for eight unusually well-observed nearby Type Ia supernova (SNe) are fitted by a newly developed template-building algorithm, using light-curve functions that are smooth, flexible, and free of potential bias from externally derived templates and other prior assumptions. From the available literature, photometric BVRI data collected over many months, including the earliest points, are reconciled, combined, and fitted to a unique time of explosion for each SN. On average, after they are corrected for light-curve decline rate, three SNe rise in 18.81 {+-} 0.36 days, while five SNe rise in 16.64 {+-} 0.21 days. If all eight SNe are sampled from a single parent population (a hypothesis not favored by statistical tests), the rms intrinsic scatter of the decline-rate-corrected SN rise time is 0.96{sub -0.25}{sup +0.52} days--a first measurement of this dispersion. The corresponding global mean rise time is 17.44 {+-} 0.39 days, where the uncertainty is dominated by intrinsic variance. This value is {approx}2 days shorter than two published averages that nominally are twice as precise, though also based on small samples. When comparing high-z to low-z SN luminosities for determining cosmological parameters, bias can be introduced by use of a light-curve template with an unrealistic rise time. If the period over which light curves are sampled depends on z in a manner typical of current search and measurement strategies, a two-day discrepancy in template rise time can bias the luminosity comparison by {approx}0.03 magnitudes.

  15. Lithium niobate stress gauge current diagnostic for noninductive measurement of fast-rise-time multimegampere currents

    NASA Astrophysics Data System (ADS)

    Hanson, D. L.; Williams, R. R.; Porter, J. L.; Spielman, R. B.; Matzen, M. K.

    1990-11-01

    Accurate modeling of load behavior in Z-pinch plasma radiation sources driven by high-current generators requires the measurement of fast-rise-time multimegampere currents close to the load. Conventional current diagnostics mounted in inductive cavities (such as B-dot loops and Rogowski coils) fail at small radius because of electrical breakdown produced by high dI/dt. In this paper, we describe the use of large-signal, nanosecond-time-resolution lithium niobate piezoelectric stress gauges to directly measure the magnetic pressure B2/2μ0=μ0I2/8π2r2 generated at radius r by a current I flowing in a radial transmission line. Current measurements have been performed at radius r=2.54×10-2 m on Sandia National Laboratories' Proto-II (10 TW) and SATURN (30 TW) gas puff Z-pinch experiments with maximum currents of 10.1 MA and dI/dt to 2.1×1014 A/s. Comparisons with Faraday rotation and B-dot current diagnostic measurements at large radius are presented. Bremsstrahlung noise problems unique to the SATURN gas puff source are discussed. For a Y-cut lithium niobate stress gauge on a pure tungsten electrode, current densities up to I/2πr=78 MA/m can be measured before the electrode yield strength and the piezoelectric operating stress limit are exceeded. Above the Hugoniot elastic limit of the electrode material, the dynamic range and accuracy of the diagnostic are greatly reduced, but it appears that the technique can be extended to higher current densities using an X-cut quartz piezoelectric element and a tungsten-sapphire electrode impedance stack.

  16. EARLY-PHASE PHOTOMETRY AND SPECTROSCOPY OF TRANSITIONAL TYPE Ia SN 2012ht: DIRECT CONSTRAINT ON THE RISE TIME

    SciTech Connect

    Yamanaka, Masayuki; Nogami, Daisaku; Maeda, Keiichi; Kawabata, Miho; Masumoto, Kazunari; Matsumoto, Katsura; Tanaka, Masaomi; Takaki, Katsutoshi; Ueno, Issei; Itoh, Ryosuke; Kawabata, Koji S.; Moritani, Yuki; Akitaya, Hiroshi; Yoshida, Michitoshi; Arai, Akira; Honda, Satoshi; Nishiyama, Koichi; Kabashima, Fujio

    2014-02-20

    We report photometric and spectroscopic observations of the nearby Type Ia Supernova (SN Ia) 2012ht from –15.8 days to +49.1 days after B-band maximum. The decline rate of the light curve is Δm {sub 15}(B) = 1.39 ± 0.05 mag, which is intermediate between normal and subluminous SNe Ia, and similar to that of the ''transitional'' Type Ia SN 2004eo. The spectral line profiles also closely resemble those of SN 2004eo. We were able to observe SN 2012ht at a very early phase, when it was still rising and was about three magnitudes fainter than at the peak. The rise time to the B-band maximum is estimated to be 17.6 ± 0.5 days and the time of the explosion is MJD 56277.98 ± 0.13. SN 2012ht is the first transitional SN Ia whose rise time is directly measured without using light curve templates, and the fifth SN Ia overall. This rise time is consistent with those of the other four SNe within the measurement error, even including the extremely early detection of SN 2013dy. The rising part of the light curve can be fitted by a quadratic function, and shows no sign of a shock-heating component due to the interaction of the ejecta with a companion star. The rise time is significantly longer than that inferred for subluminous SNe such as SN 1991bg, which suggests that a progenitor and/or explosion mechanism of transitional SNe Ia are more similar to normal SNe Ia rather than to subluminous SNe Ia.

  17. MOSFET solid state switching circuit improves the 0 to 99% rise time for framing camera deflection electronics

    SciTech Connect

    Rivera, A.T.; Thomas, S.

    1996-09-01

    We have improved the 0 to 99% rise time voltage on our 2 frame deflection plates from 160 to 65 nS with the addition of a peaking circuit that works in conjunction with our primary 2 frame deflection circuitry. Our peaking technique has applications to other HV pulsers including those which must drive 51 ohm loads. Generally, rise time voltages are measured between 10 and 90%. To minimize the camera image blur resulting from the dynamic influence of deflection plate potentials acting on photocathode electrons, it was necessary to design a circuit that would rise from 0 to the 99% voltage level in under 100nS. Once this voltage was reached, it was necessary to stay within 1% of the attained voltage level for a duration of 1 uS. This was accomplished with the use of MOSFET solid state switching.

  18. Turbulence Scales, Rise Times, Caustics, and the Simulation of Sonic Boom Propagation

    NASA Technical Reports Server (NTRS)

    Pierce, Allan D.

    1996-01-01

    The general topic of atmospheric turbulence effects on sonic boom propagation is addressed with especial emphasis on taking proper and efficient account of the contributions of the portion oi the turbulence that is associated with extremely high wavenumber components. The recent work reported by Bart Lipkens in his doctoral thesis is reexamined to determine whether the good agreement between his measured rise times with the 1971 theory of the author is fortuitous. It is argued that Lipken's estimate of the distance to the first caustic was a gross overestimate because of the use of a sound speed correlation function shaped like a gaussian curve. In particular, it is argued that the expected distance to the first caustic varies with the kinematic viscosity nu and the energy epsilon dissipated per unit mass per unit time, and the sound speed c as : d(sub first caustic) = nu(exp 7/12) c(exp 2/3)/ epsilon(exp 5/12)(nu x epsilon/c(exp 4))(exp a), where the exponent a is greater than -7/12 and can be argued to be either O or 1/24. In any event, the surprising aspect of the relationship is that it actually goes to zero as the viscosity goes to zero with s held constant. It is argued that the apparent overabundance of caustics can be grossly reduced by a general computational and analytical perspective that partitions the turbulence into two parts, divided by a wavenumber k(sub c). Wavenumbers higher than kc correspond to small-scale turbulence, and the associated turbulence can be taken into account by a renormalization of the ambient sound speed so that the result has a small frequency dependence that results from a spatial averaging over of the smaller-scale turbulent fluctuations. Selection of k(sub c). can be made so large that only a very small number of caustics are encountered if one adopts the premise that the frequency dispersion of pulses is caused by that part of the turbulence spectrum which lies in the inertial range originally predicted by Kolmogoroff. The

  19. Learning Novel Phonological Representations in Developmental Dyslexia: Associations with Basic Auditory Processing of Rise Time and Phonological Awareness

    ERIC Educational Resources Information Center

    Thomson, Jennifer M.; Goswami, Usha

    2010-01-01

    Across languages, children with developmental dyslexia are known to have impaired lexical phonological representations. Here, we explore associations between learning new phonological representations, phonological awareness, and sensitivity to amplitude envelope onsets (rise time). We show that individual differences in learning novel phonological…

  20. Pseudo-Steady Diffusional Growth or Collapse of Bubbles Rising in Time Dependent Pressure Fields

    DTIC Science & Technology

    1990-03-13

    et al. [12], Ishikawa, et al. [13] and Payvar [14] to name a few. Brankovic, et al. collected data for air and carbon dioxide bubbles with a triple...hydrostatic pressure field. Payvar [141 examined the effects, both experimentally and analytically, of a rapid de- compression on bubble growth for C0 2...Furthermore, bubble experimental rise data have only been obtained for a static hydrostatic head, with the exception of Payvar [14], but that was for a

  1. Rise time reduction of thermal actuators operated in air and water through optimized pre-shaped open-loop driving

    NASA Astrophysics Data System (ADS)

    Larsen, T.; Doll, J. C.; Loizeau, F.; Hosseini, N.; Peng, A. W.; Fantner, G. E.; Ricci, A. J.; Pruitt, B. L.

    2017-04-01

    Electrothermal actuators have many advantages compared to other actuators used in micro-electro-mechanical systems (MEMS). They are simple to design, easy to fabricate and provide large displacements at low voltages. Low voltages enable less stringent passivation requirements for operation in liquid. Despite these advantages, thermal actuation is typically limited to a few kHz bandwidth when using step inputs due to its intrinsic thermal time constant. However, the use of pre-shaped input signals offers a route for reducing the rise time of these actuators by orders of magnitude. We started with an electrothermally actuated cantilever having an initial 10–90% rise time of 85 μs in air and 234 μs in water for a standard open-loop step input. We experimentally characterized the linearity and frequency response of the cantilever when operated in air and water, allowing us to obtain transfer functions for the two cases. We used these transfer functions, along with functions describing desired reduced rise-time system responses, to numerically simulate the required input signals. Using these pre-shaped input signals, we improved the open-loop 10–90% rise time from 85 μs to 3 μs in air and from 234 μs to 5 μs in water, an improvement by a factor of 28 and 47, respectively. Using this simple control strategy for MEMS electrothermal actuators makes them an attractive alternative to other high speed micromechanical actuators such as piezoelectric stacks or electrostatic comb structures which are more complex to design, fabricate, or operate.

  2. Interaction-powered supernovae: rise-time versus peak-luminosity correlation and the shock-breakout velocity

    SciTech Connect

    Ofek, Eran O.; Arcavi, Iair; Tal, David; Gal-Yam, Avishay; Ben-Ami, Sagi; De Cia, Annalisa; Yaron, Ofer; Sullivan, Mark; Kulkarni, Shrinivas R.; Cao, Yi; Nugent, Peter E.; Bersier, David; Cenko, S. Bradley; Filippenko, Alexei V.; Fransson, Claes; Kasliwal, Mansi M.; Laher, Russ; Surace, Jason; Quimby, Robert

    2014-06-20

    Interaction of supernova (SN) ejecta with the optically thick circumstellar medium (CSM) of a progenitor star can result in a bright, long-lived shock-breakout event. Candidates for such SNe include Type IIn and superluminous SNe. If some of these SNe are powered by interaction, then there should be a specific relation between their peak luminosity, bolometric light-curve rise time, and shock-breakout velocity. Given that the shock velocity during shock breakout is not measured, we expect a correlation, with a significant spread, between the rise time and the peak luminosity of these SNe. Here, we present a sample of 15 SNe IIn for which we have good constraints on their rise time and peak luminosity from observations obtained using the Palomar Transient Factory. We report on a possible correlation between the R-band rise time and peak luminosity of these SNe, with a false-alarm probability of 3%. Assuming that these SNe are powered by interaction, combining these observables and theory allows us to deduce lower limits on the shock-breakout velocity. The lower limits on the shock velocity we find are consistent with what is expected for SNe (i.e., ∼10{sup 4} km s{sup –1}). This supports the suggestion that the early-time light curves of SNe IIn are caused by shock breakout in a dense CSM. We note that such a correlation can arise from other physical mechanisms. Performing such a test on other classes of SNe (e.g., superluminous SNe) can be used to rule out the interaction model for a class of events.

  3. Early to Rise? The Effect of Daily Start Times on Academic Performance

    ERIC Educational Resources Information Center

    Edwards, Finley

    2012-01-01

    Local school districts often stagger daily start times for their schools in order to reduce busing costs. This paper uses data on all middle school students in Wake County, NC from 1999 to 2006 to identify the causal effect of daily start times on academic performance. Using variation in start times within schools over time, the effect is a two…

  4. Spark-Timing Control Based on Correlation of Maximum-Economy Spark Timing, Flame-front Travel, and Cylinder-Pressure Rise

    NASA Technical Reports Server (NTRS)

    Cook, Harvey A; Heinicke, Orville H; Haynie, William H

    1947-01-01

    An investigation was conducted on a full-scale air-cooled cylinder in order to establish an effective means of maintaining maximum-economy spark timing with varying engine operating conditions. Variable fuel-air-ratio runs were conducted in which relations were determined between the spark travel, and cylinder-pressure rise. An instrument for controlling spark timing was developed that automatically maintained maximum-economy spark timing with varying engine operating conditions. The instrument also indicated the occurrence of preignition.

  5. Gender Differences in Time Use among Adolescents in Developing Countries: Implications of Rising School Enrollment Rates

    ERIC Educational Resources Information Center

    Lloyd, Cynthia B.; Grant, Monica; Ritchie, Amanda

    2008-01-01

    This comparative analysis of gender differences in time use among adolescents uses surveys from five developing countries and is motivated by an interest in gender role socialization and gendered patterns of behavior during adolescence. Exploring differences in work (both noneconomic household work and labor market work) and leisure time among…

  6. Extracting Short Rise-Time Velocity Profiles with Digital Down-Shift Analysis of Optically Up-Converted PDV Data

    SciTech Connect

    Abel Diaz, Nathan Riley, Cenobio Gallegos, Matthew Teel, Michael Berninger, Thomas W. Tunnell

    2010-09-08

    This work describes the digital down-shift (DDS) technique, a new method of extracting short rise-time velocity profiles in the analysis of optically up-converted PDV data. The DDS technique manipulates the PDV data by subtracting a constant velocity (i.e., the DDS velocity νDDS) from the velocity profile. DDS exploits the simple fact that the optically up-converted data ride on top of a base velocity (ν0, the apparent velocity at no motion) with a rapid rise to a high velocity (νf) of a few km/s or more. Consequently, the frequency content of the signal must describe a velocity profile that increases from ν0 to ν0 + νf. The DDS technique produces velocity reversals in the processed data before shock breakout when ν0 < νDDS < ν0 + νf. The DDS analysis process strategically selects specific DDS velocities (velocity at which the user down shifts the data) that produce anomalous reversals (maxima and/or minima), which are predictable and easy to identify in the mid-range of the data. Additional analysis determines when these maxima and minima occur. By successive application of the DDS technique and iterative analysis, velocity profiles are extracted as time as a function of velocity rather than as a function of time as it would be in a conventional velocity profile. Presented results include a description of DDS, velocity profiles extracted from laser-driven shock data with rise times of 200 ps or less, and a comparison with other techniques.

  7. The rise of global warming skepticism: exploring affective image associations in the United States over time.

    PubMed

    Smith, Nicholas; Leiserowitz, Anthony

    2012-06-01

    This article explores how affective image associations to global warming have changed over time. Four nationally representative surveys of the American public were conducted between 2002 and 2010 to assess public global warming risk perceptions, policy preferences, and behavior. Affective images (positive or negative feelings and cognitive representations) were collected and content analyzed. The results demonstrate a large increase in "naysayer" associations, indicating extreme skepticism about the issue of climate change. Multiple regression analyses found that holistic affect and "naysayer" associations were more significant predictors of global warming risk perceptions than cultural worldviews or sociodemographic variables, including political party and ideology. The results demonstrate the important role affective imagery plays in judgment and decision-making processes, how these variables change over time, and how global warming is currently perceived by the American public.

  8. Time Evolution of Plasma Parameters during the Rise of a Solar Prominence Instability

    NASA Astrophysics Data System (ADS)

    Orozco Suárez, D.; Díaz, A. J.; Asensio Ramos, A.; Trujillo Bueno, J.

    2014-04-01

    We present high-spatial resolution spectropolarimetric observations of a quiescent hedgerow prominence taken in the He I 1083.0 nm triplet. The observation consisted of a time series in sit-and-stare mode of ~36 minutes duration. The spectrograph's slit crossed the prominence body and we recorded the time evolution of individual vertical threads. Eventually, we observed the development of a dark Rayleigh-Taylor plume that propagated upward with a velocity, projected onto the plane of the sky, of 17 km s-1. Interestingly, the plume apex collided with the prominence threads pushing them aside. We inferred Doppler shifts, Doppler widths, and magnetic field strength variations by interpreting the He I Stokes profiles with the HAZEL code. The Doppler shifts show that clusters of threads move coherently while individual threads have oscillatory patterns. Regarding the plume we found strong redshifts (~9-12 km s-1) and large Doppler widths (~10 km s-1) at the plume apex when it passed through the prominence body and before it disintegrated. We associate the redshifts with perspective effects while the Doppler widths are more likely due to an increase in the local temperature. No local variations of the magnetic field strength associated with the passage of the plume were found; this leads us to conclude that the plumes are no more magnetized than the surroundings. Finally, we found that some of the threads' oscillations are locally damped, what allowed us to apply prominence seismology techniques to infer additional prominence physical parameters.

  9. Temperature Rise Induced by Light Curing Unit Can Shorten Enamel Acid-Etching Time

    PubMed Central

    Najafi Abrandabadi, Ahmad; Sheikh-Al-Eslamian, Seyedeh Mahsa; Panahandeh, Narges

    2015-01-01

    Objectives: The aim of this in-vitro study was to assess the thermal effect of light emitting diode (LED) light curing unit on the enamel etching time. Materials and Methods: Three treatment groups with 15 enamel specimens each were used in this study: G1: Fifteen seconds of etching, G2: Five seconds of etching, G3: Five seconds of etching plus LED light irradiation (simultaneously). The micro shear bond strength (μSBS) of composite resin to enamel was measured. Results: The mean μSBS values ± standard deviation were 51.28±2.35, 40.47±2.75 and 50.00±2.59 MPa in groups 1, 2 and 3, respectively. There was a significant difference between groups 1 and 2 (P=0.013) and between groups 2 and 3 (P=0.032) in this respect, while there was no difference between groups 1 and 3 (P=0.932). Conclusion: Simultaneous application of phosphoric acid gel over enamel surface and light irradiation using a LED light curing unit decreased enamel etching time to five seconds without compromising the μSBS. PMID:27559352

  10. TIME EVOLUTION OF PLASMA PARAMETERS DURING THE RISE OF A SOLAR PROMINENCE INSTABILITY

    SciTech Connect

    Orozco Suárez, D.; Asensio Ramos, A.; Trujillo Bueno, J.; Díaz, A. J.

    2014-04-10

    We present high-spatial resolution spectropolarimetric observations of a quiescent hedgerow prominence taken in the He I 1083.0 nm triplet. The observation consisted of a time series in sit-and-stare mode of ∼36 minutes duration. The spectrograph's slit crossed the prominence body and we recorded the time evolution of individual vertical threads. Eventually, we observed the development of a dark Rayleigh-Taylor plume that propagated upward with a velocity, projected onto the plane of the sky, of 17 km s{sup –1}. Interestingly, the plume apex collided with the prominence threads pushing them aside. We inferred Doppler shifts, Doppler widths, and magnetic field strength variations by interpreting the He I Stokes profiles with the HAZEL code. The Doppler shifts show that clusters of threads move coherently while individual threads have oscillatory patterns. Regarding the plume we found strong redshifts (∼9-12 km s{sup –1}) and large Doppler widths (∼10 km s{sup –1}) at the plume apex when it passed through the prominence body and before it disintegrated. We associate the redshifts with perspective effects while the Doppler widths are more likely due to an increase in the local temperature. No local variations of the magnetic field strength associated with the passage of the plume were found; this leads us to conclude that the plumes are no more magnetized than the surroundings. Finally, we found that some of the threads' oscillations are locally damped, what allowed us to apply prominence seismology techniques to infer additional prominence physical parameters.

  11. Characterizing and minimizing the effects of noise in tide gauge time series: relative and geocentric sea level rise around Australia

    NASA Astrophysics Data System (ADS)

    Burgette, Reed J.; Watson, Christopher S.; Church, John A.; White, Neil J.; Tregoning, Paul; Coleman, Richard

    2013-08-01

    We quantify the rate of sea level rise around the Australian continent from an analysis of tide gauge and Global Positioning System (GPS) data sets. To estimate the underlying linear rates of sea level change in the presence of significant interannual and decadal variability (treated here as noise), we adopt and extend a novel network adjustment approach. We simultaneously estimate time-correlated noise as well as linear model parameters and realistic uncertainties from sea level time series at individual gauges, as well as from time-series differences computed between pairs of gauges. The noise content at individual gauges is consistent with a combination of white and time-correlated noise. We find that the noise in time series from the western coast of Australia is best described by a first-order Gauss-Markov model, whereas east coast stations generally exhibit lower levels of time-correlated noise that is better described by a power-law process. These findings suggest several decades of monthly tide gauge data are needed to reduce rate uncertainties to <0.5 mm yr-1 for undifferenced single site time series with typical noise characteristics. Our subsequent adjustment strategy exploits the more precise differential rates estimated from differenced time series from pairs of tide gauges to estimate rates among the network of 43 tide gauges that passed a stability analysis. We estimate relative sea level rates over three temporal windows (1900-2011, 1966-2011 and 1993-2011), accounting for covariance between time series. The resultant adjustment reduces the rate uncertainty across individual gauges, and partially mitigates the need for century-scale time series at all sites in the network. Our adjustment reveals a spatially coherent pattern of sea level rise around the coastline, with the highest rates in northern Australia. Over the time periods beginning in 1900, 1966 and 1993, we find weighted average rates of sea level rise of 1.4 ± 0.6, 1.7 ± 0.6 and 4.6 ± 0

  12. The Effect of Driver Rise-Time on Pinch Current and its Impact on Plasma Focus Performance and Neutron Yield

    NASA Astrophysics Data System (ADS)

    Sears, Jason; Schmidt, Andrea; Link, Anthony; Welch, Dale

    2016-10-01

    Experiments have suggested that dense plasma focus (DPF) neutron yield increases with faster drivers [Decker NIMP 1986]. Using the particle-in-cell code LSP [Schmidt PRL 2012], we reproduce this trend in a kJ DPF [Ellsworth 2014], and demonstrate how driver rise time is coupled to neutron output. We implement a 2-D model of the plasma focus including self-consistent circuit-driven boundary conditions. Driver capacitance and voltage are varied to modify the current rise time, and anode length is adjusted so that run-in coincides with the peak current. We observe during run down that magnetohydrodynamic (MHD) instabilities of the sheath shed blobs of plasma that remain in the inter-electrode gap during run in. This trailing plasma later acts as a low-inductance restrike path that shunts current from the pinch during maximum compression. While the MHD growth rate increases slightly with driver speed, the shorter anode of the fast driver allows fewer e-foldings and hence reduces the trailing mass between electrodes. As a result, the fast driver postpones parasitic restrikes and maintains peak current through the pinch during maximum compression. The fast driver pinch therefore achieves best simultaneity between its ion beam and peak target density, which maximizes neutron production. Prepared by LLNL under Contract DE-AC52-07NA27344.

  13. Characteristics of a fast rise time power supply for a pulsed plasma reactor for chemical vapor destruction

    SciTech Connect

    Lawless, P.A.; Yamamoto, Toshiaki; Shofran, S.P.; Boss, C.B.; Nunez, C.M.; Ramsey, G.H.; Engels, R.L.

    1996-11-01

    Rotating spark gap devices for switching high-voltage direct current (dc) into a corona plasma reactor can achieve pulse rise times in the range of tens of nanoseconds. The fast rise times lead to vigorous plasma generation without sparking at instantaneous applied voltages higher than can be obtained with dc. The resulting energetic plasma is effective for destroying a variety of molecules. The spark gap circuit configuration plays an important role in the effectiveness of the plasma generation. A single-gap circuit is effective for generating moderate peak voltages, but is limited by a multiple sparking phenomenon. A double-gap circuit can achieve equal peak voltages with every spark, but with a reduced number of pulses, compared to the single gap. Both configurations have an upper voltage imposed by the changing impedance of the reactor as voltage and frequency are varied. The pulse characteristics are reported for both types of circuits. The general performance of the reactors for destruction of some compounds with both circuits is also reported.

  14. Skin explosion of double-layer conductors in fast-rising high magnetic fields

    NASA Astrophysics Data System (ADS)

    Chaikovsky, S. A.; Oreshkin, V. I.; Datsko, I. M.; Labetskaya, N. A.; Ratakhin, N. A.

    2014-04-01

    An experiment has been performed to study the electrical explosion of thick cylindrical conductors using the MIG pulsed power generator capable of producing a peak current of 2.5 MA within 100 ns rise time. The experimental goal was to compare the skin explosion of a solid conductor with that of a double-layer conductor whose outer layer had a lower conductivity than the inner one. It has been shown that in magnetic fields of peak induction up to 300 T and average induction rise rate 3 × 109 T/s, the double-layer structure of a conductor makes it possible to achieve higher magnetic induction at the conductor surface before it explodes. This can be accounted for, in particular, by the reduction of the ratio of the Joule heat density to the energy density of the magnetic field at the surface of a double-layer conductor due to redistribution of the current density over the conductor cross section.

  15. RISE TIME DELAY DISCRIMINATOR

    DOEpatents

    Johnstone, C.W.

    1959-09-29

    A pulse-height discriminator for generating an output pulse when the accepted input pulse is approximately at its maximum value is described. A gating tube and a negative bias generator responsive to the derivative of the input pulse and means for impressing the output of the bias generator to at least one control electrode of the gating tube are included.

  16. Investigation on F layer height rise and equatorial spread F onset time: Signature of standing large-scale wave

    NASA Astrophysics Data System (ADS)

    Joshi, Lalit Mohan; Balwada, S.; Pant, T. K.; Sumod, S. G.

    2015-04-01

    Equatorial spread F observations have been categorized into three categories based on ionograms recorded over Sriharikota. First category comprised cases where the onset of equatorial spread F (ESF) was concurrent with the peak h'F time. Second and third categories comprised cases where the onset of ESF happened with a delay of 30 min and more than 30 min, respectively, with reference to the peak h'F time. Average peak h'F in the first category was more than 35 km higher than that in the second and third categories. Also, the peak vertical (upward) plasma drift was higher in the first category. Assuming the genesis of F region irregularity to have happened at or before the time of F layer attaining the peak height, late onset of ESF indicates the genesis of irregularities to have happened westward of Sriharikota. The fact that the peak h'F values were remarkably different in the three categories indicates a zonal variation of eastward electric field and postsunset height rise of F layer. The relative magnitude of the F layer height rise in the three different categories over Sriharikota has also been found to be significantly different than that over Thumba, an equatorial (magnetic) station located ~360 km westward of Sriharikota longitude. This scenario points toward the existence of a large-scale zonal standing wave in the F layer and its important role in F region instability process. Results presented in the manuscript have been discussed in the light of current understanding on the large-scale wave structure.

  17. High-voltage isolation transformer for sub-nanosecond rise time pulses constructed with annular parallel-strip transmission lines.

    PubMed

    Homma, Akira

    2011-07-01

    A novel annular parallel-strip transmission line was devised to construct high-voltage high-speed pulse isolation transformers. The transmission lines can easily realize stable high-voltage operation and good impedance matching between primary and secondary circuits. The time constant for the step response of the transformer was calculated by introducing a simple low-frequency equivalent circuit model. Results show that the relation between the time constant and low-cut-off frequency of the transformer conforms to the theory of the general first-order linear time-invariant system. Results also show that the test transformer composed of the new transmission lines can transmit about 600 ps rise time pulses across the dc potential difference of more than 150 kV with insertion loss of -2.5 dB. The measured effective time constant of 12 ns agreed exactly with the theoretically predicted value. For practical applications involving the delivery of synchronized trigger signals to a dc high-voltage electron gun station, the transformer described in this paper exhibited advantages over methods using fiber optic cables for the signal transfer system. This transformer has no jitter or breakdown problems that invariably occur in active circuit components.

  18. Development of a novel voltage divider for measurement of sub-nanosecond rise time high voltage pulses

    NASA Astrophysics Data System (ADS)

    Mitra, S.; Senthil, K.; Singh, S. K.; Kumar, Ranjeet; Sharma, Archana

    2016-02-01

    This paper is about the development of a copper sulphate based aqueous-electrolytic voltage divider for the measurement of high voltage pulses, 100 kV, with pulse widths of 1-2 ns and rise time <1 ns. Novel features are incorporated in the design of the divider, to meet the performance requirements for the application. Analytical calculations to justify design are described. Structural simulation of the divider is carried out using field wave simulation software to verify the effectiveness. A calibration procedure has been developed to calibrate the divider. Results obtained during calibration are subjected to statistical analysis to determine the confidence of measurement. Details of design, analysis, and simulation are described in this paper.

  19. A TRANSIT TIMING ANALYSIS OF NINE RISE LIGHT CURVES OF THE EXOPLANET SYSTEM TrES-3

    SciTech Connect

    Gibson, N. P.; Pollacco, D.; Simpson, E. K.; Barros, S.; Joshi, Y. C.; Todd, I.; Keenan, F. P.; Skillen, I.; Benn, C.; Christian, D.; Hrudkova, M.; Steele, I. A.

    2009-08-01

    We present nine newly observed transits of TrES-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. A Markov-Chain Monte Carlo analysis was used to determine the planet-star radius ratio and inclination of the system, which were found to be R{sub p} /R {sub *} = 0.1664{sup +0.0011} {sub -0.0018} and i = 81.73{sup +0.13} {sub -0.04}, respectively, consistent with previous results. The central transit times and uncertainties were also calculated, using a residual-permutation algorithm as an independent check on the errors. A re-analysis of eight previously published TrES-3 light curves was conducted to determine the transit times and uncertainties using consistent techniques. Whilst the transit times were not found to be in agreement with a linear ephemeris, giving {chi}{sup 2} = 35.07 for 15 degrees of freedom, we interpret this to be the result of systematics in the light curves rather than a real transit timing variation. This is because the light curves that show the largest deviation from a constant period either have relatively little out-of-transit coverage or have clear systematics. A new ephemeris was calculated using the transit times and was found to be T{sub c} (0) = 2454632.62610 {+-} 0.00006 HJD and P = 1.3061864 {+-} 0.0000005 days. The transit times were then used to place upper mass limits as a function of the period ratio of a potential perturbing planet, showing that our data are sufficiently sensitive to have probed sub-Earth mass planets in both interior and exterior 2:1 resonances, assuming that the additional planet is in an initially circular orbit.

  20. Copernicus Rising

    NASA Astrophysics Data System (ADS)

    Rose, Michael A.

    2007-08-01

    Copernicus Rising began as a historical biography when it was first conceived, but as the writing progressed it quickly became a rather absurd play that took historical research and twisted it through the lens of my own wit, philosophy and personal affection for the characters. When working with historical figures--characters who existed in a very tangible way in our own history--the playwriting process opens a dialogue between different points in time and space. The difficulty lies in finding a unique and clear voice amongst the discordant personalities involved in this time and space overlap, both in the writing and production processes, in order to get to the heart of what the play is really all about. This thesis follows the journey of the play from its historical roots through the creation of an absurd journey both insides and outside time, space and the human mind. The first part of the thesis explains the beginnings of the concept and outlines much of the research and development that went into the play. The next part outlines the process of production and integrating the world on paper with that of moving bodies on stage. In the final part, post-production discussions and audience feedback sessions shape the play into the draft included in this thesis.

  1. Rise time and formant transition duration in the discrimination of speech sounds: the Ba-Wa distinction in developmental dyslexia.

    PubMed

    Goswami, Usha; Fosker, Tim; Huss, Martina; Mead, Natasha; Szucs, Dénes

    2011-01-01

    Across languages, children with developmental dyslexia have a specific difficulty with the neural representation of the sound structure (phonological structure) of speech. One likely cause of their difficulties with phonology is a perceptual difficulty in auditory temporal processing (Tallal, 1980). Tallal (1980) proposed that basic auditory processing of brief, rapidly successive acoustic changes is compromised in dyslexia, thereby affecting phonetic discrimination (e.g. discriminating /b/ from /d/) via impaired discrimination of formant transitions (rapid acoustic changes in frequency and intensity). However, an alternative auditory temporal hypothesis is that the basic auditory processing of the slower amplitude modulation cues in speech is compromised (Goswami et al., 2002). Here, we contrast children's perception of a synthetic speech contrast (ba/wa) when it is based on the speed of the rate of change of frequency information (formant transition duration) versus the speed of the rate of change of amplitude modulation (rise time). We show that children with dyslexia have excellent phonetic discrimination based on formant transition duration, but poor phonetic discrimination based on envelope cues. The results explain why phonetic discrimination may be allophonic in developmental dyslexia (Serniclaes et al., 2004), and suggest new avenues for the remediation of developmental dyslexia.

  2. Measuring charge transport from transient photovoltage rise times. A new tool to investigate electron transport in nanoparticle films.

    PubMed

    O'Regan, Brian C; Bakker, Klaas; Kroeze, Jessica; Smit, Herman; Sommeling, Paul; Durrant, James R

    2006-08-31

    Charge transport rate at open-circuit potential (V(oc)) is proposed as a new characterization method for dye-sensitized (DS) and other nanostructured solar cells. At V(oc), charge density is flat and measurable, which simplifies quantitative comparison of transport and charge density. Transport measured at V(oc) also allows meaningful comparison of charge transport rates between different treatments, temperatures, and types of cells. However, in typical DS cells, charge transport rates at V(oc) often cannot be measured by photocurrent transients or modulation techniques due to RC limitations and/or recombination losses. To circumvent this limitation, we show that charge transport at V(oc) can be determined directly from the transient photovoltage rise time using a simple, zero-free-parameter model. This method is not sensitive to RC limitation or recombination losses. In trap limited devices, such as DS cells, the comparison of transport rates between different devices or conditions is only valid when the Fermi level in the limiting conductor is at the same distance from the band edge. We show how to perform such comparisons, correcting for conduction band shifts using the density of states (DOS) distribution determined from the same photovoltage transients. Last we show that the relationship between measured transport rate and measured charge density is consistent with the trap limited transport model.

  3. Excited-state intramolecular proton transfer in 3-hyroxyflavone isolated in solid argon: fluorescence and fluorescence-excitation spectra and tautomer fluorescence rise time

    SciTech Connect

    Dick, B.; Ernsting, N.P.

    1987-07-30

    The fluorescence properties of 3-hydroxyflavone isolated in solid argon at 15 K have been investigated. Upon electronic excitation the molecules undergo rapid intramolecular proton transfer. No fluorescence from the excited state of the normal form of the molecule could be detected. Perturbations due to hydrogen-bonding impurities which produce serious experimental problems in hydrocarbon glasses are largely suppressed in argon matrices. The rise of the green fluorescence of the tautomer was studied with excitation pulses of 230-fs duration and streak camera detection. An apparent tautomer fluorescence rise time of 2.7 ps was obtained by deconvolution. A comparative measurement of the dye coumarine 6 yielded an apparent fluorescence rise time of 2.5 ps, which can be entirely attributed to the group velocity dispersion of the streak camera optics. This indicates a rate constant for excited-state intramolecular proton transfer in 3-hydroxyflavone of greater than 10/sup 12/ s/sup -1/.

  4. Summary of Sonic Boom Rise Times Observed During FAA Community Response Studies over a 6-Month Period in the Oklahoma City Area

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.; Sothcott, Victor E.

    1990-01-01

    The sonic boom signature data acquired from about 1225 supersonic flights, over a 6-month period in 1964 in the Oklahoma City area, was enhanced with the addition of data relating to rise times and total signature duration. These later parameters, not available at the time of publication of the original report on the Oklahoma City sonic boom exposures, are listed in tabular form along with overpressure, positive impulse, positive duration, and waveform category. Airplane operating information along with the surface weather observations are also included. Sonic boom rise times include readings to the 1/2, 3/4, and maximum overpressure values. Rise time relative probabilities for various lateral locations from the ground track of 0, 5, and 10 miles are presented along with the variation of rise times with flight altitude. The tabulated signature data, along with corresponding airplane operating conditions and surface and upper level atmospheric information, are also available on electronic files to provide it in the format for more efficient and effective utilization.

  5. Note: A rectangular pulse generator for 50 kV voltage, 0.8 ns rise time, and 10 ns pulse width based on polymer-film switch

    NASA Astrophysics Data System (ADS)

    Wu, Hanyu; Zhang, Xinjun; Sun, Tieping; Zeng, Zhengzhong; Cong, Peitian; Zhang, Shaoguo

    2015-10-01

    In this article, we describe a rectangular pulse generator, consisting of a polymer-film switch, a tri-plate transmission line, and parallel post-shaped ceramic resistor load, for 50-kV voltage, 0.8-ns rise time, and 10-ns width. The switch and resistors are arranged in atmospheric air and the transmission line can work in atmospheric air or in transformer oil to change the pulse width from 6.7 ns to 10 ns. The fast switching and low-inductance characteristics of the polymer-film switch ensure the fast rising wavefront of <1 ns. This generator can be applied in the calibration of nanosecond voltage dividers and used for electromagnetic pulse tests as a fast-rising current injection source.

  6. Magnetic Piston Propagation in a 100-ns Plasma Opening Switch

    NASA Astrophysics Data System (ADS)

    Weingarten, A.; Grabowski, C.; Chakrabarti, N.; Maron, Y.; Fruchtman, A.

    1998-11-01

    The propagation of a magnetic piston through the plasma of a 90-ns, 170-kA POS is observed by studying the electron density, magnetic field, and ion velocity evolution. For the prefilled plasma n_e=(2.2± 0.5)× 10^14 cm-3, and T_e=5.5± 1 eV. The plasma composition is studied from absolute line intensities and collisional-radiative calculations. Most of the plasma ions are protons (90% near the cathode) with the rest being mainly CIV. The Hall-MHD conditions are not fulfilled for our experiment and ion motion is significant. The 3D-resolved ne evolution during the current pulse is studied from the line intensities of ions doped in the plasma using laser evaporation, and the magnetic field from Zeeman splitting. A diagonal magnetic piston propagates from the generator towards the load at about half the proton Alfven velocity. The protons are specularly reflected by the piston, while the heavy ions cross the potential hill in the piston, acquiring a lower velocity. The proton reflection causes an increase of ne ahead of the piston, followed by a sharp (10-20 ns) and substantial drop in ne (to 10-50% from the initial value). The magnetic field distribution studied using chordal observation, and theoretical analysis of ne and the magnetic field evolution are presented.

  7. Television viewing, internet use, and self-reported bedtime and rise time in adults: implications for sleep hygiene recommendations from an exploratory cross-sectional study.

    PubMed

    Custers, Kathleen; Van den Bulck, Jan

    2012-01-01

    This study examined whether the availability of the Internet and TV in the bedroom and overall Internet use and TV viewing were related to sleep variables in a sample of 711 residents of Flanders, Belgium. Although the relations were small, there was some evidence of time shifting: Internet access in the bedroom predicted later bedtime (β = .12, p < .05) and later rise time (β = .11, p < .05) on weekdays and later bedtime (β = .10, p < .001) on weekends. Internet use volume predicted later bedtime (β = .10, p < .001) and rise time (β = .07, p < .05) on weekends, and TV viewing predicted later bedtime (β = .10, p < .05) on weekends. However, neither the availability of the Internet or TV in the bedroom, nor the volume of Internet use or TV viewing, was a significant predictor of reduced sleep window or tiredness. Reducing media use might not be important for sleep hygiene advice to adults.

  8. Ciguatera incidence in the US Virgin Islands has not increased over a 30-year time period despite rising seawater temperatures.

    PubMed

    Radke, Elizabeth G; Grattan, Lynn M; Cook, Robert L; Smith, Tyler B; Anderson, Donald M; Morris, J Glenn

    2013-05-01

    Ciguatera fish poisoning is the most common marine food poisoning worldwide. It has been hypothesized that increasing seawater temperature will result in increasing ciguatera incidence. In St. Thomas, US Virgin Islands, we performed an island-wide telephone survey (N = 807) and a medical record review of diagnosed ciguatera cases at the emergency department of the sole hospital and compared these data with comparable data sources collected in 1980. Annual incidence from both recent data sources remained high (12 per 1,000 among adults in the telephone survey). However, the combined data sources suggest that incidence has declined by 20% or more or remained stable over 30 years, whereas seawater temperatures were increasing. Illness was associated with lower education levels, higher levels of fish consumption, and having previous episodes of ciguatera; population shifts from 1980 to 2010 in these factors could explain an incidence decline of approximately 3 per 1,000, obscuring effects from rising seawater temperature.

  9. Assessment of Temperature Rise and Time of Alveolar Ridge Splitting by Means of Er:YAG Laser, Piezosurgery, and Surgical Saw: An Ex Vivo Study.

    PubMed

    Matys, Jacek; Flieger, Rafał; Dominiak, Marzena

    2016-01-01

    The most common adverse effect after bone cutting is a thermal damage. The aim of our study was to evaluate the bone temperature rise during an alveolar ridge splitting, rating the time needed to perform this procedure and the time to raise the temperature of a bone by 10°C, as well as to evaluate the bone carbonization occurrence. The research included 60 mandibles (n = 60) of adult pigs, divided into 4 groups (n = 15). Two vertical and one horizontal cut have been done in an alveolar ridge using Er:YAG laser with set power of 200 mJ (G1), 400 mJ (G2), piezosurgery unit (G3), and a saw (G4). The temperature was measured by K-type thermocouple. The highest temperature gradient was noted for piezosurgery on the buccal and lingual side of mandible. The temperature rises on the bone surface along with the increase of laser power. The lower time needed to perform ridge splitting was measured for a saw, piezosurgery, and Er:YAG laser with power of 400 mJ and 200 mJ, respectively. The temperature rise measured on the bone over 10°C and bone carbonization occurrence was not reported in all study groups. Piezosurgery, Er:YAG laser (200 mJ and 400 mJ), and surgical saw are useful and safe tools in ridge splitting surgery.

  10. Assessment of Temperature Rise and Time of Alveolar Ridge Splitting by Means of Er:YAG Laser, Piezosurgery, and Surgical Saw: An Ex Vivo Study

    PubMed Central

    Flieger, Rafał; Dominiak, Marzena

    2016-01-01

    The most common adverse effect after bone cutting is a thermal damage. The aim of our study was to evaluate the bone temperature rise during an alveolar ridge splitting, rating the time needed to perform this procedure and the time to raise the temperature of a bone by 10°C, as well as to evaluate the bone carbonization occurrence. The research included 60 mandibles (n = 60) of adult pigs, divided into 4 groups (n = 15). Two vertical and one horizontal cut have been done in an alveolar ridge using Er:YAG laser with set power of 200 mJ (G1), 400 mJ (G2), piezosurgery unit (G3), and a saw (G4). The temperature was measured by K-type thermocouple. The highest temperature gradient was noted for piezosurgery on the buccal and lingual side of mandible. The temperature rises on the bone surface along with the increase of laser power. The lower time needed to perform ridge splitting was measured for a saw, piezosurgery, and Er:YAG laser with power of 400 mJ and 200 mJ, respectively. The temperature rise measured on the bone over 10°C and bone carbonization occurrence was not reported in all study groups. Piezosurgery, Er:YAG laser (200 mJ and 400 mJ), and surgical saw are useful and safe tools in ridge splitting surgery. PMID:27957502

  11. Discretization in time gives rise to noise-induced improvement of the signal-to-noise ratio in static nonlinearities

    NASA Astrophysics Data System (ADS)

    Davidović, A.; Huntington, E. H.; Frater, M. R.

    2009-07-01

    For some nonlinear systems the performance can improve with an increasing noise level. Such noise-induced improvement in static nonlinearities is of great interest for practical applications since many systems can be modeled in that way (e.g., sensors, quantizers, limiters, etc.). We present experimental evidence that noise-induced performance improvement occurs in those systems as a consequence of discretization in time with the achievable signal-to-noise ratio (SNR) gain increasing with decreasing ratio of input noise bandwidth and total measurement bandwidth. By modifying the input noise bandwidth, noise-induced improvement with SNR gain larger than unity is demonstrated in a system where it was not previously thought possible. Our experimental results bring closer two different theoretical models for the same class of nonlinearities and shed light on the behavior of static nonlinear discrete-time systems.

  12. Origin of abrupt rise in deuteron NMR longitudinal relaxation times of protein methyl groups below 90 K.

    PubMed

    Vugmeyster, Liliya; Ostrovsky, Dmitry; Lipton, Andrew S

    2013-05-23

    In order to examine the origin of the abrupt change in the temperature dependence of (2)H NMR longitudinal relaxation times observed previously for methyl groups of L69 in the hydrophobic core of villin headpiece protein at around 90 K (Vugmeyster et al. J. Am. Chem. Soc. 2010, 132, 4038-4039), we extended the measurements to several other methyl groups in the hydrophobic core. We show that, for all methyl groups, relaxation times experience a dramatic jump several orders of magnitude around this temperature. Theoretical modeling supports the conclusion that the origin of the apparent transition in the relaxation times is due to the existence of the distribution of conformers distinguished by their activation energy for methyl three-site hops. It is also crucial to take into account the differential contribution of individual conformers into overall signal intensity. When a particular conformer approaches the regime at which its three-site hop rate constant is on the order of the quadrupolar coupling interaction constant, the intensity of the signal due to this conformer experiences a sharp drop, thus changing the balance of the contributions of different conformers into the overall signal. As a result, the observed apparent transition in the relaxation rates can be explained without the assumption of an underlying transition in the rate constants. This work in combination with earlier results also shows that the model based on the distribution of conformers explains the relaxation behavior in the entire temperature range between 300 and 70 K.

  13. Origin of Abrupt Rise in Deuteron NMR Longitudinal Relaxation Times of Protein Methyl Groups Below 90 K

    SciTech Connect

    Vugmeyster, Liliya; Ostrovsky, Dmitry; Lipton, Andrew S.

    2013-05-23

    In order to examine the origin of the abrupt change in the temperature dependence of NMR longitudinal relaxation times observed earlier for methyl groups of L69 in the hydrophobic core of villin headpiece protein at around 90 K (Vugmeyster et al. J. Am. Chem. Soc. 2010, 132, 4038), we extended the measurements to several other methyl groups in the hydrophobic core. We show that for all methyl groups, relaxation times experience a dramatic jump several orders of magnitude around this temperature. Theoretical modeling supports the conclusion that the origin of the apparent transition in the relaxation times is due to the existence of the distribution of conformers distinguished by their activation energy for methyl three-site hops. It is also crucial to take into account the differential contribution of individual conformers into overall signal intensity. When a particular conformer approaches the regime at which its three-site hops rate constant is on the order of the quadrupolar coupling interaction constant, the intensity of the signal due to this conformer experiences a sharp drop, thus changing the balance of the contributions of different conformers into the overall signal. As a result, the observed apparent transition in the relaxation rates can be explained without the assumption of an underlying transition in the rate constants. This work in combination with earlier results also shows that the model based on the distribution of conformers explains the relaxation behavior in the entire temperature range between 300-70 K.

  14. Persistent perceptual delay for head movement onset relative to auditory stimuli of different durations and rise times.

    PubMed

    Barnett-Cowan, Michael; Raeder, Sophie M; Bülthoff, Heinrich H

    2012-07-01

    The perception of simultaneity between auditory and vestibular information is crucially important for maintaining a coherent representation of the acoustic environment whenever the head moves. It has been recently reported, however, that despite having similar transduction latencies, vestibular stimuli are perceived significantly later than auditory stimuli when simultaneously generated. This suggests that perceptual latency of a head movement is longer than a co-occurring sound. However, these studies paired a vestibular stimulation of long duration (~1 s) and of a continuously changing temporal envelope with a brief (10-50 ms) sound pulse. In the present study, the stimuli were matched for temporal envelope duration and shape. Participants judged the temporal order of the two stimuli, the onset of an active head movement and the onset of brief (50 ms) or long (1,400 ms) sounds with a square- or raised-cosine-shaped envelope. Consistent with previous reports, head movement onset had to precede the onset of a brief sound by about 73 ms in order for the stimuli to be perceived as simultaneous. Head movements paired with long square sounds (~100 ms) were not significantly different than brief sounds. Surprisingly, head movements paired with long raised-cosine sound (~115 ms) had to be presented even earlier than brief stimuli. This additional lead time could not be accounted for by differences in the comparison stimulus characteristics (temporal envelope duration and shape). Rather, differences between sound conditions were found to be attributable to variability in the time for head movement to reach peak velocity: the head moved faster when paired with a brief sound. The persistent lead time required for vestibular stimulation provides further evidence that the perceptual latency of vestibular stimulation is greater than the other senses.

  15. [The reasons and background for the rise of college education of Traditional Chinese Medicine (TCM) in modern times].

    PubMed

    Yang, Wen-jie; Huang, Ying; Li, Jie

    2009-09-01

    With western learning spreading throughout the orient, the survival and development of TCM was restrained to a large degree due to the medical administrative policy, educational system and diffusion of western medicine at different social levels. Facing this adversity, the TCM sector complied with the changing times and survived through persistent efforts as well as wide and solid popular foundations, striving actively for the legitimacy status of TCM education and establishing several TCM colleges. During the course of running the colleges, the TCM sector was brave in changing ideas and giving and accepting new knowledge, it explored a comprehensive educational syllabus, which not only promoted the development of TCM education in the Republican period of China, but also laid a foundation for TCM education in the new period.

  16. Simulation and measurement of pulse height and rise-time for electron signals in CZT detectors:. influence of material and electronics parameters

    NASA Astrophysics Data System (ADS)

    Mathy, F.; Bonnefoy, J. P.; Gliere, A.; Mestais, C.; Verger, L.

    2001-02-01

    A model for simulation of amplitude vs. rise-time biparametric spectra as a function of CZT materials properties was developed. This model takes into account the physical properties of the CZT detectors, the electric field profile and the physics of γ- ray interaction with CZT. The model has been refined to include the filtering effects of the front-end electronics and applied again to biparametric spectra. The electronic filtering is represented by a combination of linear band pass filters. The rise-time measurement circuit induces a non-linearity that is taken into account. A comparison between the electronics simulations and calibration measurements on the actual circuits is presented. In addition, physical and electrical properties of several CZT samples have been characterized and these properties have been incorporated in the model so that actual and simulated biparametric spectra can be compared. Finally, the model is applied to show the influence of the main physical parameters (mobility and lifetime) and of the applied electric field on the biparametric spectra.

  17. Precise timing of deglacial tropical warming and humidification in the Timor Sea vs Antarctic warming and global atmospheric CO2 rise

    NASA Astrophysics Data System (ADS)

    Sarnthein, M.; Grootes, P. M.; Holbourn, A.; Kuhnt, W.

    2009-04-01

    The centennial-scale phasing of climate events in the ocean, cryo-, and atmosphere provides crucial new insights into causal linkages that have controlled the events of global climate change during the last deglacial. During Termination Ia, a first significant sea level rise occurred as early as 19.4-18.7 ka (Hanebuth et al., 2008), a first Antarctic warming followed only 18.0/17.8 to 14.7 ka (Kawamura et al., 2007), a minor atmospheric CO2 rise after 17.5 ka, and a major rise at 16.7-14.5 ka (Monnin et al., 2001). Major progress in the precise age control of associated marine climate events resulted from accepting the results of the 14C plateau-tuning method (Sarnthein et al., 2007). Accordingly, 14C reservoir ages of surface waters revealed strong temporal and spatial changes for different parts of the ocean in contrast to the previously assumed constant modern global average of 400 yr. New plateau-tuning based age estimates from the Timor Sea (Core MD01-2378) exhibit a decrease in surface water ages from >2200 yr prior to 16 ka to 410 yr subsequent to 15 ka, thus providing a much improved basis for radiocarbon-based age control of deglacial events in tropical paleoceanography. Accordingly, the benthic delta18O record of deglacial ice melt and intermediate-water warming (near 1700 m w.d.) indeed reflects a first minor response to Antarctic warming after 17.8 ka, a major response, however, only from 17.0-14.4 ka. Likewise, major sea surface warming started almost 1000 yr after Antarctic warming, at 17 ka, almost coeval with the major deglacial rise in atmospheric CO2. In part, this warming may reflect a cease in the upwelling of intermediate waters along the eastern margin of the Indian Ocean, which is documented by a coeval major increase in the Mg/Ca-based temperature gradient between surface and thermocline waters and a halving of (chlorine) productivity at 16.8-16.5 ka, moreover, by the strong decrease in surface water reservoir ages, starting with 800 yr

  18. Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET.

    PubMed

    Gundacker, Stefan; Auffray, Etiennette; Pauwels, Kristof; Lecoq, Paul

    2016-04-07

    The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time (τd) and the number of photons detected (n'), i.e. CTR proportional variant √τd/n'. However, it is still an open question to what extent the scintillation rise time (τr) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, prompt photons (Cherenkov) can be observed at the beginning of the scintillation event. Furthermore a significantly lower rise time value is observed when codoping with calcium. To quantitatively investigate the influence of the rise time to the time resolution we measured the CTR with the same L(Y)SO samples and compared the values to Monte Carlo simulations. Using the measured relative light yields, rise- and decay times of the scintillators we are able to quantitatively understand the measured CTRs in our simulations. Although the rise time is important to fully explain the CTR variation for the different samples tested we determined its influence on the CTR to be in the order of a few percent only. This result is surprising because, if only photonstatistics of the scintillation process is considered, the CTR would be proportional to the square root of the rise time. The unexpected small rise time influence on the CTR can be explained by the convolution of the scintillation rate with the single photon time

  19. Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET

    NASA Astrophysics Data System (ADS)

    Gundacker, Stefan; Auffray, Etiennette; Pauwels, Kristof; Lecoq, Paul

    2016-04-01

    The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time ({τd} ) and the number of photons detected ({{n}\\prime} ), i.e. CTR\\propto \\sqrt{{τd}/{{n}\\prime}} . However, it is still an open question to what extent the scintillation rise time ({τr} ) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, prompt photons (Cherenkov) can be observed at the beginning of the scintillation event. Furthermore a significantly lower rise time value is observed when codoping with calcium. To quantitatively investigate the influence of the rise time to the time resolution we measured the CTR with the same L(Y)SO samples and compared the values to Monte Carlo simulations. Using the measured relative light yields, rise- and decay times of the scintillators we are able to quantitatively understand the measured CTRs in our simulations. Although the rise time is important to fully explain the CTR variation for the different samples tested we determined its influence on the CTR to be in the order of a few percent only. This result is surprising because, if only photonstatistics of the scintillation process is considered, the CTR would be proportional to the square root of the rise time. The unexpected small rise time influence on the CTR can be explained by the convolution of the scintillation rate with the

  20. Measuring Mars sand flux seasonality from a time series of HiRISE images and calibrating the threshold for sand mobility

    NASA Astrophysics Data System (ADS)

    Ayoub, F.; Avouac, J.; Newman, C. E.; Richardson, M. I.; Lucas, A.; Leprince, S.; Bridges, N. T.

    2013-12-01

    In this study, focused on the Nili Patera dune field on Mars, we measured the temporal variation of the migration rate of sand ripples from the correlation of a time-series of HiRISE images using COSI-Corr. The time-series covers approximately 1.5 Mars year which allows us to observe seasonal migration rate variability as well as taking an early glimpse on yearly variation. A Principal Component Analysis (PCA) was applied to the time-series to quantify more robustly the time evolution of the signal and filter out noise, in particular due to unrecorded satellite jitter. Using the first two components, which account for 82% of the variance, the seasonal variation of the ripple migration rate was estimated. We clearly observe continuously active migration throughout the year with a strong seasonal quasi-sinusoidal variation which peaks at perihelion. Coupling between surface winds and sand transport is a fundamental factor governing geological activity and climate on Mars. Saltation of sand is likely crucial for both erosion of the surface and for the emission of finer (dust) particles into the atmosphere. Analysis of the distinctive seasonal variation of sand flux with an atmospheric model is used to infer an effective threshold for sand motion. This is the first direct estimate of the stress threshold at Mars on spatial scales relevant for dynamical atmospheric modeling of sand transport, surface erosion, and dust lifting.

  1. Melting Ice, Rising Seas

    NASA Video Gallery

    Sea level rise is an indicator that our planet is warming. Much of the world's population lives on or near the coast, and rising seas are something worth watching. Sea level can rise for two reason...

  2. Contemporary sea level rise.

    PubMed

    Cazenave, Anny; Llovel, William

    2010-01-01

    Measuring sea level change and understanding its causes has considerably improved in the recent years, essentially because new in situ and remote sensing observations have become available. Here we report on most recent results on contemporary sea level rise. We first present sea level observations from tide gauges over the twentieth century and from satellite altimetry since the early 1990s. We next discuss the most recent progress made in quantifying the processes causing sea level change on timescales ranging from years to decades, i.e., thermal expansion of the oceans, land ice mass loss, and land water-storage change. We show that for the 1993-2007 time span, the sum of climate-related contributions (2.85 +/- 0.35 mm year(-1)) is only slightly less than altimetry-based sea level rise (3.3 +/- 0.4 mm year(-1)): approximately 30% of the observed rate of rise is due to ocean thermal expansion and approximately 55% results from land ice melt. Recent acceleration in glacier melting and ice mass loss from the ice sheets increases the latter contribution up to 80% for the past five years. We also review the main causes of regional variability in sea level trends: The dominant contribution results from nonuniform changes in ocean thermal expansion.

  3. Modulated single-bubble sonoluminescence: Dependence of phase of flashes, their intensity and rise/decay times on viscosity, the modulation strength, and frequency

    NASA Astrophysics Data System (ADS)

    Mastikhin, Igor; Djurkovic, Borko

    2004-05-01

    The single-bubble sonoluminescence (SBSL) signal was studied for the case of driving frequency modulated by lower frequency with an offset. In our work, the driving frequency of 28 kHz and the modulation frequencies of 25-1000 Hz were used. The modulation strength of 0.2, 0.5, and 0.8 was defined as the difference of highest and lowest pressures over modulation period. The measurements were performed for water-glycerol mixtures of various viscosities. The measured SBSL signal appeared as a train of flashes for modulation frequencies below 250 Hz, and as a continuous modulated signal for higher frequencies. At the same frequency, the flashes covered similar phase intervals for different modulation strengths and, accordingly, pressure ranges. At higher glycerol concentrations (up to 24%) both the intensity and the stability of flashes increased, due to damped shape instabilities and reduced dancing; however, the phase interval of flashes remained about the same. Such phase-locked behavior can be explained by translational movements of the bubble due to modulated Bjerknes force and changes in the symmetry of the bubble collapse. The changes in intensities and rise/decay times can serve as a measure of the gas exchange between the bubble and its surroundings during silent and luminescent intervals.

  4. Sonic-boom measurements in the focus region during the ascent of Apollo 17. [maximum positive overpressure, positive impulse, signature duration, and bow-shock rise time

    NASA Technical Reports Server (NTRS)

    Henderson, H. R.; Hilton, D. A.

    1974-01-01

    Sonic-boom pressure signatures recorded during the ascent phase of Apollo 17 are presented. The measurements were obtained onboard six U.S. Navy ships positioned along the ground track of the spacecraft vehicle in the area of expected focus resulting from the flight path and acceleration of the vehicle. Tracings of the measured signatures are presented along with values of the maximum positive overpressure, positive impulse, signature duration, and bowshock rise time. Also included are brief descriptions of the ships and their location, the deployment of the sonic-boom instrumentation, flight profiles and operating conditions for the launch vehicle and spacecraft, surface-weather and sea-state information at the measuring sites, and high-altitude weather information for the general measurement areas. Comparisons of the measured and predicted sonic-boom overpressures for the Apollo 17 mission are presented. The measured data are also compared with data from the Apollo 15 and 16 missions and data from flight test programs of various aircraft.

  5. Structural Theories and Race-Specific Drug Arrests: What Structural Factors Account for the Rise in Race-Specific Drug Arrests over Time?

    ERIC Educational Resources Information Center

    Parker, Karen F.; Maggard, Scott R.

    2005-01-01

    Studies examining the structural correlates of urban crime have generated a large body of research; however, few studies have linked the structural conditions to race-specific drug arrests. In this study, the authors examine the impact of urban disadvantage, social disorganization, and racial threat indicators on the rise in race-specific drug…

  6. Ground potential rise monitor

    DOEpatents

    Allen, Zachery W [Mandan, ND; Zevenbergen, Gary A [Arvada, CO

    2012-04-03

    A device and method for detecting ground potential rise (GPR) comprising positioning a first electrode and a second electrode at a distance from each other into the earth. The voltage of the first electrode and second electrode is attenuated by an attenuation factor creating an attenuated voltage. The true RMS voltage of the attenuated voltage is determined creating an attenuated true RMS voltage. The attenuated true RMS voltage is then multiplied by the attenuation factor creating a calculated true RMS voltage. If the calculated true RMS voltage is greater than a first predetermined voltage threshold, a first alarm is enabled at a local location. If user input is received at a remote location acknowledging the first alarm, a first alarm acknowledgment signal is transmitted. The first alarm acknowledgment signal is then received at which time the first alarm is disabled.

  7. Evidence for influence of the Galápagos hotspot on the East Pacific Rise MORB composition during times of superfast spreading

    NASA Astrophysics Data System (ADS)

    Geldmacher, J.; Höfig, T.; Hauff, S. F.; Hoernle, K.; Garbe-Schoenberg, C.

    2011-12-01

    ODP/IODP Hole 1256D on the Cocos Plate is located on oceanic crust that formed 15 m.y. ago at the East Pacific Rise (EPR) during a period of superfast spreading (~11-20 Ma). This site is considered to be a reference site for crust formed during fast (>8 cm/y) and particularly superfast (>20 cm/y) spreading rates. The question exists whether its formation was geochemically influenced by the Galápagos hotspot. Today, the effect of the Galápagos hotspot on mid ocean ridge geochemistry can only be seen along the Cocos-Nasca Spreading Center (located immediately north of the hotspot). It has been speculated that Galápagos plume material might have reached the EPR during times of superfast spreading due to processes such as increased "ridge suction" (Niu & Hékinian, 2004). To test this idea, MORB samples from several DSDP, ODP and IODP drill sites that formed along the EPR between 3°S and 7°N and between 9 and 21 Ma have been studied to delineate any effect of the Galápagos hotspot on their geochemistry. N-MORB from sites formed during times of superfast spreading show slighty, but systematically, lower incompatible element ratios (e.g. La/Yb < 0.65, Ce/Lu <0.76), compared to rocks formed shortly before, or after, superfast spreading (La/Yb >0.66, Ce/Lu >0.8). In addition, the melts formed during superfast spreading show generally higher Eu/Hf and Eu/Eu* ratios which is interpreted to indicate a recycled gabbroic component in their source. Despite their more depleted incompatible trace element patterns, Pb (double-spike) and Nd isotope ratios of the superfast spreading MORB are enriched (higher 206Pb/204Pb, 207Pb/204Pb and lower 143Nd/144Nd) compared to the samples from MORB created during normal spreading. The combined trace element and isotope data suggest that EPR MORB created during superfast spreading was formed by greater degrees of melting of a possibly trace element depleted, but isotopically enriched source component. It is suggested that the source of

  8. The rising risks of rising tides

    SciTech Connect

    Hanson, H.; Lindh, G.

    1996-12-31

    The erosion of beaches, flooding of agricultural land, and intrusion of saltwater into coastal streams could become a reality if temperatures climb. Over the past century, sea levels have risen 4 to 6 inches. Now, the Intergovernmental panel on Climate Change (IPCC) predicts that sea levels will rise between 8 and 28 inches by 2070, say Hans Hanson, associate professor emeritus in the Department of Water Resources Engineering at the University of Lund in Sweden. Coastal communities, which harbor more than half the world`s population, are poorly equipped to combat the threat of encroaching waters. {open_quotes}Few public officials have developed comprehensive strategies to address the potential consequences of sea-level rise,{close_quotes} the authors say. In response to the lack of long-term strategies to address the potential consequences of sea-level rise,{close_quotes} the authors say. In response to the lack of long-term strategies, the IPCC has recommended that coastal nations implement coastal-zone management plans by 2000. {open_quotes}Low-lying islands and high-use, developed coastal areas... face an urgent need to develop strategies for coping with sea-level rise,{close_quotes} the authors conclude.

  9. Systematic investigation of effects of exciton–acoustic-phonon scattering on photoluminescence rise times of free excitons in GaAs/Al{sub 0.3}Ga{sub 0.7}As single quantum wells

    SciTech Connect

    Nakayama, Masaaki Ohno, Tatsuya; Furukawa, Yoshiaki

    2015-04-07

    We have systematically investigated the photoluminescence (PL) dynamics of free excitons in GaAs/Al{sub 0.3}Ga{sub 0.7}As single quantum wells, focusing on the energy relaxation process due to exciton–acoustic-phonon scattering under non-resonant and weak excitation conditions as a function of GaAs-layer thickness from 3.6 to 12.0 nm and temperature from 30 to 50 K. The free exciton characteristics were confirmed by observation that the PL decay time has a linear dependence with temperature. We found that the free exciton PL rise rate, which is the reciprocal of the rise time, is inversely linear with the GaAs-layer thickness and linear with temperature. This is consistent with a reported theoretical study of the exciton–acoustic-phonon scattering rate in the energy relaxation process in quantum wells. Consequently, it is conclusively verified that the PL rise rate is dominated by the exciton–acoustic-phonon scattering rate. In addition, from quantitative analysis of the GaAs-layer thickness and temperature dependences, we suggest that the PL rise rate reflects the number of exciton–acoustic-phonon scattering events.

  10. Acronical Risings and Settings

    NASA Astrophysics Data System (ADS)

    Hockey, Thomas A.

    2012-01-01

    A concept found in historical primary sources, and useful in contemporary historiography, is the acronical rising and setting of stars (or planets). Topocentric terms, they provide information about a star's relationship to the Sun and thus its visibility in the sky. Yet there remains ambiguity as to what these two phrases actually mean. "Acronical” is said to have come from the Greek akros ("point,” "summit,” or "extremity") and nux ("night"). While all sources agree that the word is originally Greek, there are alternate etymologies for it. A more serious difficulty with acronical rising and setting is that there are two competing definitions. One I call the Poetical Definition. Acronical rising (or setting) is one of the three Poetical Risings (or Settings) known to classicists. (The other two are cosmical rising/setting, discussed below, and the more familiar helical rising/setting.) The term "poetical" refers to these words use in classical poetry, e. g., that of Columella, Hesiod, Ovid, Pliny the Younger, and Virgil. The Poetical Definition of "acronical” usually is meant in this context. The Poetical Definition of "acronical” is as follows: When a star rises as the Sun sets, it rises acronically. When a star sets as the Sun sets, it sets acronically. In contrast with the Poetical Definition, there also is what I call the Astronomical Definition. The Astronomical Definition is somewhat more likely to appear in astronomical, mathematical, or navigational works. When the Astronomical Definition is recorded in dictionaries, it is often with the protasis "In astronomy, . . . ." The Astronomical Definition of "acronical” is as follows: When a star rises as the Sun sets, it rises acronically. When a star sets as the Sun rises, it sets acronically. I will attempt to sort this all out in my talk.

  11. Tharsis Rise Graben

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 22 May 2002) The Science This image is located in the northwestern portion of the Tharsis Rise at about 12 N and 125 W (235 E). What is immediately noticeable in this image is the series of linear features that are called graben. These features are associated with crustal extension which results in a series of up and down blocks of crust that run perpendicular to the direction of the extension. Images of Mars have shown a large number of these tectonic features concentrated on or near the Tharsis region. The Tharsis region is an enormous bulge that causes major tectonic disruptions across the planet when it tries to settle down from its height and reach equilibrium with the rest of the planet. The graben in this image display a number of preferential directions indicating that the crustal stresses that caused the graben have changed over time. By examining the cross-cutting relationships between the features, it is possible to reassemble the history of the area. The Story Now, if you thought that Mars was almost perfectly round, think again! The red planet has a large bulge sticking out from it called Tharsis. Almost 3,000 miles across, this enormous region rises almost four miles above the average radius of the planet. That's quite a bulge! Since Tharsis the land of the largest volcanoes in the solar system, it may have been formed by both the uplift of land from tectonic action and the build-up of lava flows. Tharsis can cause some pretty major tectonic disruptions across the planet when it tries to settle down from its height and reach a better equilibrium with the rest of the planet. In this image, located in the northwestern portion of the Tharsis Rise, a whole lot of lowered features stripe the landscape. They are called grabens, and formed when the crust of the planet was stretched tectonically. This kind of crustal extension (or stretching) tends to form a series of up-and-down blocks of crust that run perpendicular to the direction of the crustal

  12. Perceptual Temporal Asymmetry Associated with Distinct ON and OFF Responses to Time-Varying Sounds with Rising versus Falling Intensity: A Magnetoencephalography Study.

    PubMed

    Zhang, Yang; Cheng, Bing; Koerner, Tess K; Schlauch, Robert S; Tanaka, Keita; Kawakatsu, Masaki; Nemoto, Iku; Imada, Toshiaki

    2016-08-05

    This magnetoencephalography (MEG) study investigated evoked ON and OFF responses to ramped and damped sounds in normal-hearing human adults. Two pairs of stimuli that differed in spectral complexity were used in a passive listening task; each pair contained identical acoustical properties except for the intensity envelope. Behavioral duration judgment was conducted in separate sessions, which replicated the perceptual bias in favour of the ramped sounds and the effect of spectral complexity on perceived duration asymmetry. MEG results showed similar cortical sites for the ON and OFF responses. There was a dominant ON response with stronger phase-locking factor (PLF) in the alpha (8-14 Hz) and theta (4-8 Hz) bands for the damped sounds. In contrast, the OFF response for sounds with rising intensity was associated with stronger PLF in the gamma band (30-70 Hz). Exploratory correlation analysis showed that the OFF response in the left auditory cortex was a good predictor of the perceived temporal asymmetry for the spectrally simpler pair. The results indicate distinct asymmetry in ON and OFF responses and neural oscillation patterns associated with the dynamic intensity changes, which provides important preliminary data for future studies to examine how the auditory system develops such an asymmetry as a function of age and learning experience and whether the absence of asymmetry or abnormal ON and OFF responses can be taken as a biomarker for certain neurological conditions associated with auditory processing deficits.

  13. Perceptual Temporal Asymmetry Associated with Distinct ON and OFF Responses to Time-Varying Sounds with Rising versus Falling Intensity: A Magnetoencephalography Study

    PubMed Central

    Zhang, Yang; Cheng, Bing; Koerner, Tess K.; Schlauch, Robert S.; Tanaka, Keita; Kawakatsu, Masaki; Nemoto, Iku; Imada, Toshiaki

    2016-01-01

    This magnetoencephalography (MEG) study investigated evoked ON and OFF responses to ramped and damped sounds in normal-hearing human adults. Two pairs of stimuli that differed in spectral complexity were used in a passive listening task; each pair contained identical acoustical properties except for the intensity envelope. Behavioral duration judgment was conducted in separate sessions, which replicated the perceptual bias in favour of the ramped sounds and the effect of spectral complexity on perceived duration asymmetry. MEG results showed similar cortical sites for the ON and OFF responses. There was a dominant ON response with stronger phase-locking factor (PLF) in the alpha (8–14 Hz) and theta (4–8 Hz) bands for the damped sounds. In contrast, the OFF response for sounds with rising intensity was associated with stronger PLF in the gamma band (30–70 Hz). Exploratory correlation analysis showed that the OFF response in the left auditory cortex was a good predictor of the perceived temporal asymmetry for the spectrally simpler pair. The results indicate distinct asymmetry in ON and OFF responses and neural oscillation patterns associated with the dynamic intensity changes, which provides important preliminary data for future studies to examine how the auditory system develops such an asymmetry as a function of age and learning experience and whether the absence of asymmetry or abnormal ON and OFF responses can be taken as a biomarker for certain neurological conditions associated with auditory processing deficits. PMID:27527227

  14. Inertial Rise in Short Capillaries

    NASA Astrophysics Data System (ADS)

    Shardt, Orest; Waghmare, Prashant; Mitra, Sushanta; Derksen, Jos

    2013-11-01

    We investigate the primarily inertial rise of liquid in vertical glass capillaries that are shorter than the equilibrium rise height (Jurin height). We focus on the behavior of the liquid upon reaching the top of the capillary and use high-speed imaging to observe the motion of the liquid-air interface with high spatial and temporal resolution. We examine the dependence of the interface behavior on the meniscus speed and capillary height and describe a new phenomenon. Upon reaching the upper edge of a sufficiently short capillary, the meniscus inverts, rises upward, and bulges out radially. The bulging liquid then wets the external surface of the capillary and slides down. The meniscus inside the capillary retracts, falling below the upper edge, and then oscillates vertically with decaying amplitude, inverting several times before reaching a steady shape. A theoretical analysis is used to interpret the conditions required for this phenomenon to occur. A key assumption in the analysis is that the transient flow is inertial and therefore the capillary driving force is balanced by the weight and inertia of the rising liquid column while viscous forces are comparatively small. The analysis points to the possibility of obtaining previously-unseen behavior under reduced gravity.

  15. Global sea level rise

    SciTech Connect

    Douglas, B.C. )

    1991-04-15

    Published values for the long-term, global mean sea level rise determined from tide gauge records exhibit considerable scatter, from about 1 mm to 3 mm/yr. This disparity is not attributable to instrument error; long-term trends computed at adjacent sites often agree to within a few tenths of a millimeter per year. Instead, the differing estimates of global sea level rise appear to be in large part due to authors' using data from gauges located at convergent tectonic plate boundaries, where changes of land elevation give fictitious sea level trends. In addition, virtually all gauges undergo subsidence or uplift due to postglacial rebound (PGR) from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling PGR by the ICE-3G model of Tushingham and Peltier (1991) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. The value for mean sea level rise obtained from a global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 is 1.8 mm/yr {plus minus} 0.1. This result provides confidence that carefully selected long tide gauge records measure the same underlying trend of sea level and that many old tide gauge records are of very high quality.

  16. Simple approximations for estimating quickly the motion and timing of salt diapir rise, overhang development, and associated thermal anomalies using present-day observations: Case history from the Gulf of Mexico and Danish North Sea

    SciTech Connect

    Lerche, I. ); Thomsen, R.O. )

    1993-09-01

    Estimates of the upward motion of salt, due solely to buoyancy forces, through deposited and depositing sedimentary cover can be split into several parts: the critical thickness of sedimentary cover necessary to cause an underlying salt to become buoyant; the critical thickness of sedimentary cover necessary for a salt diapir to reach the sediment mudline in the absence of an impeding pressure of competent sediments opposing salt rise and in the absence of significant overpressure (both differential impedance and differential overpressure will slow the rise of the salt to the mudline); the effective speed of motion of the salt through the nonimpeding sediments during the salt's buoyant-ascent phase; current observed salt-top depth below mudline versus nonimpeded predicted salt-top depth leading to (a) minimum estimate of mechanical strength of competent resistive layers, and (b) an approximate estimate of buoyancy pressure of salt attempting to penetrate the resistive cover layer; uplift estimate of the overlying competent sediments because of the buoyancy pressure, in relation to observed uplift, leading to an estimate of salt-diapir rise speed since reaching the impeding formation; timing estimates of [open quotes]mushroom cap[close quotes] development of salt since emplacement of the resistive overlying layer and an estimate of the lateral competence of sedimentary beds ahead of the mushroom-salt sheet cap as a consequence of the observed mushroom extent; an estimate of evolving thermal anomalies around the dynamic salt/sediment system as a consequence of high-salt thermal conductivity. Such simple rough estimation methods are important in assessing the local and regional factors influencing the dynamic, thermal, and hydrocarbon retention factors in basinal sediments influenced by salt. Examples from the Gulf of Mexico and the Danish North Sea illustrate how to use both seismic and/or downhole data to perform the simple estimates.

  17. Sea Level Rise in Tuvalu

    NASA Astrophysics Data System (ADS)

    Lin, C. C.; Ho, C. R.; Cheng, Y. H.

    2012-04-01

    Most people, especially for Pacific Islanders, are aware of the sea level change which may caused by many factors, but no of them has deeper sensation of flooding than Tuvaluan. Tuvalu, a coral country, consists of nine low-lying islands in the central Pacific between the latitudes of 5 and 10 degrees south, has the average elevation of 2 meters (South Pacific Sea Level and Climate Monitoring Project, SPSLCMP report, 2006) up to sea level. Meanwhile, the maximum sea level recorded was 3.44m on February 28th 2006 that damaged Tuvaluan's property badly. Local people called the flooding water oozes up out of the ground "King Tide", that happened almost once or twice a year, which destroyed the plant, polluted their fresh water, and forced them to colonize to some other countries. The predictable but uncontrollable king tide had been observed for a long time by SPSLCMP, but some of the uncertainties which intensify the sea level rise need to be analyzed furthermore. In this study, a span of 18 years of tide gauge data accessed from Sea Level Fine Resolution Acoustic Measuring Equipment (SEAFRAME) are compared with the satellite altimeter data accessed from Archiving Validation and Interpretation of Satellite Data in Oceanography (AVISO). All above are processed under the limitation of same time and spatial range. The outcome revealed a 9.26cm difference between both. After the tide gauge data shifted to the same base as altimeter data, the results showed the unknown residuals are always positive under the circumstances of the sea level rise above 3.2m. Apart from uncertainties in observing, the residual reflected unknown contributions. Among the total case number of sea level rise above 3.2m is 23 times, 22 of which were recorded with oceanic warm eddy happened simultaneously. The unknown residual seems precisely matched with oceanic warm eddies and illustrates a clear future approach for Tuvaluan to care for.

  18. Rise of the Andes.

    PubMed

    Garzione, Carmala N; Hoke, Gregory D; Libarkin, Julie C; Withers, Saunia; MacFadden, Bruce; Eiler, John; Ghosh, Prosenjit; Mulch, Andreas

    2008-06-06

    The surface uplift of mountain belts is generally assumed to reflect progressive shortening and crustal thickening, leading to their gradual rise. Recent studies of the Andes indicate that their elevation remained relatively stable for long periods (tens of millions of years), separated by rapid (1 to 4 million years) changes of 1.5 kilometers or more. Periodic punctuated surface uplift of mountain belts probably reflects the rapid removal of unstable, dense lower lithosphere after long-term thickening of the crust and lithospheric mantle.

  19. Chinas Rise: A Time for Choosing

    DTIC Science & Technology

    2012-06-01

    Figure 3: China vs. US Nominal GDP Source: Frederick S. Pardee Center for International Futures via Google Public Data Although GDP as reported... dam on the Parana River—something that had been a source of tension for years.40 Brazil’s president reciprocated by visiting and furthering Brazil’s

  20. Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    1998-01-01

    A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

  1. Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

    DOEpatents

    Caporaso, G.J.; Sampayan, S.E.; Kirbie, H.C.

    1998-10-13

    A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 12 figs.

  2. Was the economic crisis 1997-1998 responsible for rising suicide rates in East/Southeast Asia? A time-trend analysis for Japan, Hong Kong, South Korea, Taiwan, Singapore and Thailand.

    PubMed

    Chang, Shu-Sen; Gunnell, David; Sterne, Jonathan A C; Lu, Tsung-Hsueh; Cheng, Andrew T A

    2009-04-01

    In 1997-1998 a widespread economic crisis hit the economies of many East/Southeast Asian countries; its impact on suicide rates across the region has not been systematically documented. We investigated the impact of the Asian economic crisis (1997-1998) on suicide in Japan, Hong Kong, South Korea, Taiwan, Singapore and Thailand. Suicide and population data for the period 1985-2006 were extracted from the World Health Organisation's mortality database and Taiwanese mortality statistics. Sex-specific age-standardised suicide rates for people aged 15years or above were analysed using joinpoint regression. Trends in divorce, marriage, unemployment, gross domestic product (GDP) per capita and alcohol consumption were compared with trends in suicide rates graphically and using time-series analysis. Suicide mortality decreased in the late 1980s and early 1990s but subsequently increased markedly in all countries except Singapore, which had steadily declining suicide rates throughout the study period. Compared to 1997, male rates in 1998 rose by 39% in Japan, 44% in Hong Kong and 45% in Korea; rises in female rates were less marked. Male rates also rose in Thailand, but accurate data were incomplete. The economic crisis was associated with 10,400 more suicides in 1998 compared to 1997 in Japan, Hong Kong and Korea. Similar increases in suicide rates were not seen in Taiwan and Singapore, the two countries where the economic crisis had a smaller impact on GDP and unemployment. Time-series analyses indicated that some of the crisis's impact on male suicides was attributable to increases in unemployment. These findings suggest an association of the Asian economic crisis with a sharp increase in suicide mortality in some, but not all, East/Southeast Asian countries, and that these increases were most closely associated with rises in unemployment.

  3. Measurement of DNA translocation dynamics in a solid-state nanopore at 100-ns temporal resolution

    PubMed Central

    Shekar, Siddharth; Niedzwiecki, David J.; Chien, Chen-Chi; Ong, Peijie; Fleischer, Daniel A.; Lin, Jianxun; Rosenstein, Jacob K.; Drndic, Marija; Shepard, Kenneth L.

    2017-01-01

    Despite the potential for nanopores to be a platform for high-bandwidth study of single-molecule systems, ionic current measurements through nanopores have been limited in their temporal resolution by noise arising from poorly optimized measurement electronics and large parasitic capacitances in the nanopore membranes. Here, we present a complementary metal-oxide-semiconductor (CMOS) nanopore (CNP) amplifier capable of low noise recordings at an unprecedented 10 MHz bandwidth. When integrated with state-of-the-art solid-state nanopores in silicon nitride membranes, we achieve an SNR of greater than 10 for ssDNA translocations at a measurement bandwidth of 5 MHz, which represents the fastest ion current recordings through nanopores reported to date. We observe transient features in ssDNA translocation events that are as short as 200 ns, which are hidden even at bandwidths as high as 1 MHz. These features offer further insights into the translocation kinetics of molecules entering and exiting the pore. This platform highlights the advantages of high-bandwidth translocation measurements made possible by integrating nanopores and custom-designed electronics. PMID:27332998

  4. Capillary rise of superspreaders.

    PubMed

    Radulovic, Jovana; Sefiane, Khellil; Shanahan, Martin E R

    2011-09-15

    Trisiloxane surfactants, known as 'superspreaders', are commonly employed in numerous applications where enhanced wetting is of the utmost importance. The underlying mechanisms of superspreader wetting have been a focus of scientific interest for ca. 2 decades, and a number of mechanisms have been proposed to explain the unique trisiloxane dynamics. We have studied trisiloxane behaviour in thin capillaries to get further insight into their interfacial activity. Additionally, our knowledge of the capillary rise of superspreaders is surprisingly limited, and the effect of this extraordinary group of surfactants on capillary phenomena has been largely overlooked. Diffusion was confirmed to be the limiting factor of trisiloxane behaviour. A tentative theoretical explanation for the phenomenon studied and an appropriate mathematical model are presented. It is concluded that the enhancement of wetting due to surfactant addition is also a function of geometry: the effect is clear for a sessile drop, but more complex and less beneficial in a capillary.

  5. The rise of graphene

    NASA Astrophysics Data System (ADS)

    Geim, A. K.; Novoselov, K. S.

    2007-03-01

    Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

  6. The 2013 M8.3 Sea of Okhotsk Deep-Focus Earthquake: Rupture Beyond the Metastable Olivine Wedge and Thermally-Controlled Rise Time near the Edge of a Slab

    NASA Astrophysics Data System (ADS)

    Ampuero, J. P.; Meng, L.

    2013-12-01

    frequency (f > 0.25 Hz) source images. The southern rupture extends towards SSE over 100 km and is consistently observed across all frequency bands, although it appears intermittently as two individual subevents in the high frequency imaging. The rupture speed of both segments is on average about 3.5 km/s, 60% of the shear-wave speed, and significantly faster than the deeper 1994 Bolivian earthquake, which is compatible with the depth distribution of rupture speeds of other deep earthquakes. The difference in frequency content between the northern and southern rupture segments can be interpreted as a lateral variation of rise time controlled by the thermal thickness of the subducting slab. The earthquake occurred near the northern edge of the subducting Pacific slab. Towards the north, the younger age of the slab and the effect of the mantle flow around its edge are expected to make the slab warmer and decrease the width between given isotherms at a given depth. In dynamic rupture models, the rise time is ultimately limited by the width of the seismogenic zone. If temperature controls the seismogenic width, this results in shorter rise time and thus more energetic high frequency radiation in the north.

  7. Capillary Rise in Porous Media.

    PubMed

    Lago, Marcelo; Araujo, Mariela

    2001-02-01

    Capillary rise experiments were performed in columns filled with glass beads and Berea sandstones, using visual methods to register the advance of the water front. For the glass bead filled columns, early time data are well fitted by the Washburn equation. However, in the experiments, the advancing front exceeded the predicted equilibrium height. For large times, an algebraic behavior of the velocity of the front is observed (T. Delker et al., Phys. Rev. Lett. 76, 2902 (1996)). A model for studying the capillary pressure evolution in a regular assembly of spheres is proposed and developed. It is based on a quasi-static advance of the meniscus with a piston-like motion and allows us to estimate the hydraulic equilibrium height, with values very close to those obtained by fitting early time data to a Washburn equation. The change of regime is explained as a transition in the mechanism of advance of the meniscus. On the other hand, only the Washburn regime was observed for the sandstones. The front velocity was fitted to an algebraical form with an exponent close to 0.5, a value expected from the asymptotic limit of the Washburn equation. Copyright 2001 Academic Press.

  8. HiRISE: The People's Camera

    NASA Astrophysics Data System (ADS)

    McEwen, A. S.; Eliason, E.; Gulick, V. C.; Spinoza, Y.; Beyer, R. A.; HiRISE Team

    2010-12-01

    The High Resolution Imaging Science Experiment (HiRISE) camera, orbiting Mars since 2006 on the Mars Reconnaissance Orbiter (MRO), has returned more than 17,000 large images with scales as small as 25 cm/pixel. From it’s beginning, the HiRISE team has followed “The People’s Camera” concept, with rapid release of useful images, explanations, and tools, and facilitating public image suggestions. The camera includes 14 CCDs, each read out into 2 data channels, so compressed images are returned from MRO as 28 long (up to 120,000 line) images that are 1024 pixels wide (or binned 2x2 to 512 pixels, etc.). This raw data is very difficult to use, especially for the public. At the HiRISE operations center the raw data are calibrated and processed into a series of B&W and color products, including browse images and JPEG2000-compressed images and tools to make it easy for everyone to explore these enormous images (see http://hirise.lpl.arizona.edu/). Automated pipelines do all of this processing, so we can keep up with the high data rate; images go directly to the format of the Planetary Data System (PDS). After students visually check each image product for errors, they are fully released just 1 month after receipt; captioned images (written by science team members) may be released sooner. These processed HiRISE images have been incorporated into tools such as Google Mars and World Wide Telescope for even greater accessibility. 51 Digital Terrain Models derived from HiRISE stereo pairs have been released, resulting in some spectacular flyover movies produced by members of the public and viewed up to 50,000 times according to YouTube. Public targeting began in 2007 via NASA Quest (http://marsoweb.nas.nasa.gov/HiRISE/quest/) and more than 200 images have been acquired, mostly by students and educators. At the beginning of 2010 we released HiWish (http://www.uahirise.org/hiwish/), opening HiRISE targeting to anyone in the world with Internet access, and already more

  9. On Capillary Rise and Nucleation

    ERIC Educational Resources Information Center

    Prasad, R.

    2008-01-01

    A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

  10. The Silver Lining in Rising Health Costs.

    ERIC Educational Resources Information Center

    McDowell, Don

    2001-01-01

    Discusses the emotional, financial, and structural reasons that health care costs in the United States, and therefore for colleges, continue to rise at staggering rates. Asserts that colleges must build health care cost reality into budget strategy, and level with constituents that there will not be a solution for the cost explosion any time soon.…

  11. States' Budgets Reflect Rising Tax Collections

    ERIC Educational Resources Information Center

    Hoff, David J.

    2005-01-01

    Many state budgets are reaping the benefits of tax revenues that are rising faster than at any time since the economic slowdown ended. Overall tax collections by states rose by 11.7 percent in the first quarter of 2005, giving the legislatures extra cash to shore up school aid, increase teacher pay, and finance new initiatives such as full-day…

  12. Calculation of Temperature Rise in Calorimetry.

    ERIC Educational Resources Information Center

    Canagaratna, Sebastian G.; Witt, Jerry

    1988-01-01

    Gives a simple but fuller account of the basis for accurately calculating temperature rise in calorimetry. Points out some misconceptions regarding these calculations. Describes two basic methods, the extrapolation to zero time and the equal area method. Discusses the theoretical basis of each and their underlying assumptions. (CW)

  13. Rising cigarette prices and rising obesity: coincidence or unintended consequence?

    PubMed

    Courtemanche, Charles

    2009-07-01

    Economists have begun to debate if the rise in cigarette prices in the U.S. in recent decades has contributed to the nation's rise in obesity, reaching conclusions that are surprisingly sensitive to specification. I show that allowing for the effect to occur gradually over several years leads to the conclusion that a rise in cigarette prices is actually associated with a long-run reduction in body mass index and obesity. This result is robust to the different methodologies used in the literature. I also provide evidence that indirect effects on exercise and food consumption may explain the counterintuitive result.

  14. A flexible time recording and time correlation analysis system

    NASA Astrophysics Data System (ADS)

    Shenhav, Nathan J.; Leiferman, Gabriel; Segal, Yitzhak; Notea, Amos

    1983-02-01

    A system was developed to digitize and record the time intervals between detection event pulses, feed to its input channels from a detection device. The accumulated data is transferred continuously in real time to a dise through a PDP 11/34 minicomputer. Even though the system was designed for a specific scope, i.e., the comparative study of passive neutron nondestructive assay methods. It can be characterized by its features as a general purpose time series recorder. The time correlation analysis is performed by software after completion of the data accumulation. The digitizing clock period is selectable and any value, larger than a minimum of 100 ns may be selected. Bursts of up to 128 events with a frequency up to 10 MHz may be recorded. With the present recorder-minicomputer combination, the maximal average recording frequency is 40 kHz.

  15. Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency

    NASA Astrophysics Data System (ADS)

    Anderlini, L.; Anelli, M.; Archilli, F.; Auriemma, G.; Baldini, W.; Bencivenni, G.; Bizzeti, A.; Bocci, V.; Bondar, N.; Bonivento, W.; Bochin, B.; Bozzi, C.; Brundu, D.; Cadeddu, S.; Campana, P.; Carboni, G.; Cardini, A.; Carletti, M.; Casu, L.; Chubykin, A.; Ciambrone, P.; Dané, E.; De Simone, P.; Falabella, A.; Felici, G.; Fiore, M.; Fontana, M.; Fresch, P.; Furfaro, E.; Graziani, G.; Kashchuk, A.; Kotriakhova, S.; Lai, A.; Lanfranchi, G.; Loi, A.; Maev, O.; Manca, G.; Martellotti, G.; Neustroev, P.; Oldeman, R. G. C.; Palutan, M.; Passaleva, G.; Penso, G.; Pinci, D.; Polycarpo, E.; Saitta, B.; Santacesaria, R.; Santimaria, M.; Santovetti, E.; Saputi, A.; Sarti, A.; Satriano, C.; Satta, A.; Schmidt, B.; Schneider, T.; Sciascia, B.; Sciubba, A.; Siddi, B. G.; Tellarini, G.; Vacca, C.; Vazquez-Gomez, R.; Vecchi, S.; Veltri, M.; Vorobyev, A.

    2016-04-01

    A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20 MHz. The measured values of the dead-time range from ~ 70 ns to ~ 100 ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40 MHz and at higher luminosity.

  16. Is chair rise performance a useful measure of leg power?

    PubMed Central

    Hardy, Rebecca; Cooper, Rachel; Shah, Imran; Harridge, Stephen; Guralnik, Jack; Kuh, Diana

    2011-01-01

    Background and Aims Chair rise performance, which is simple to assess in a home or clinic setting, has been used as a method of predicting leg power deficit in older adults. More recently chair rise performance has been assessed in younger populations as a baseline for assessment of subsequent age-related declines in function and power. However, as rising from a chair repeatedly not only requires lower limb strength and power but also good balance and coordination, it may not be purely a measure of leg power especially among these younger, well functioning groups who are yet to experience age-related declines and deficits in function. The aim of this study was to assess whether chair rise performance can be considered as a predictor of leg power, and hence of deficits in this, in men and women in mid-life. We assessed the relationship of chair rise performance with leg extensor power (LEP) measured using the Nottingham Power Rig (NPR), and with standing balance performance. Methods LEP was measured in a clinic setting in a sub-sample of 81 men and 93 women from the MRC National Survey of Health and Development, a nationally representative cohort born in Britain in 1946. The time taken to rise from a chair 10 times and standing balance time were assessed during home visits at the same age. Results Increasing LEP was associated with better chair rise performance among those who completed 10 chair rises in ≥15 seconds, after adjustment for body size (p=0.008). Better standing balance performance was associated with better chair rise performance in men, but not women. Conclusions That LEP and standing balance are both related to chair rise time in men suggests that chair rise time should not be thought of purely as a proxy measure of leg power in middle-aged populations. This has implications for longitudinal studies which want to study age-related decline in chair rise performance. PMID:21422795

  17. Diabetes Continues Its Relentless Rise

    MedlinePlus

    ... medlineplus.gov/news/fullstory_164596.html Diabetes Continues Its Relentless Rise But doctors making headway with heart ... main risk factor for type 2 diabetes, though it's not the only factor involved in the disease. ...

  18. Rising Food Prices: Who's Responsible?

    ERIC Educational Resources Information Center

    Brown, Lester R.

    1973-01-01

    Rise in food prices can be partially attributed to the high food consumption level throughout Europe and North America, coupled with failure to evolve systems for more production of cattle, soybeans, and fisheries at lower cost. (PS)

  19. The rise and fall of spinning tops

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2013-04-01

    The motion of four different spinning tops was filmed with a high-speed video camera. Unlike pointed tops, tops with a rounded peg precess initially about a vertical axis that lies well outside the top, and then spiral inward until the precession axis passes through a point close to the center-of-mass. The center-of-mass of a top with a rounded peg can rise as a result of rolling rather than sliding friction, contrary to the explanation normally given for the rise of spinning tops. A tippe top was also filmed and was observed to jump vertically off a horizontal surface several times while the center-of-mass was rising, contrary to the usual assumption that the normal reaction force on a tippe top remains approximately equal to its weight. It was found that the center-of-mass of a tippe top rises as a result of rolling friction at low spin frequencies and as a result of sliding friction at high spin frequencies. It was also found that, at low spin frequencies, a tippe top can precess at two different frequencies simultaneously.

  20. Capillary rise and swelling in cellulose sponges

    NASA Astrophysics Data System (ADS)

    Ha, Jonghyun; Kim, Jungchul; Kim, Ho-Young

    2015-11-01

    A cellulose sponge, which is a mundane example of a porous hydrophilic structure, can absorb and hold a significant amount of liquid. We present the results of experimental and theoretical investigation of the dynamics of the capillary imbibition of various aqueous solutions in the sponge that swells at the same time. We find that the rate of water rise against the resistance caused by gravitational and viscous effects deviates from Washburn's rule beyond a certain threshold height. We rationalize the novel power law of the rise height versus time by combining Darcy's law with hygroscopic swelling equation and also predict the threshold height. The scaling law constructed through this work agrees well with the experimental results, shedding light on the physics of capillary flow in deforming porous media.

  1. Late Noachian development of the Coprates rise, Mars

    NASA Technical Reports Server (NTRS)

    Tanaka, Kenneth L.; Schultz, Richard A.

    1991-01-01

    The Coprates rise forms a 900 km long, north to northeast trending ridge south of Coprates Chasma between long. 56 and 60 degs. Radar and stereo photogrammetric data indicate that the rise is 2 to 4 km above a neighboring trough to the east. The break in slope between the rise and this trough is well defined topographically and in Viking images. In turn, the trough is bordered to the to the east at long. 52 deg by a much gentler rise. West of the Coprates rise, the terrain dips about 0.2 deg to roughly long. 75 deg. The rise and flanking highs were previously interpreted to be tilted fault blocks formed by either Tharsis tectonism or an ancient impact. Results are now reported of a preliminary geologic study that documents Late Noachian growth of the Coprates rise as a asymmetric fold. More comprehensive work will lead to a mechanical analysis of the kinematic development of the rise. It is concluded that the Coprate rise formed during the Late Noachian by 2 to 4 km of asymmetric uplift (steeper on its east flank). The timing is inconsistent with an origin by an early impact, but it coincides in time with early Tharsis centered radial faulting at Syria Planum.

  2. Bottlenecks aggravate rising construction costs

    SciTech Connect

    2008-05-15

    Rising demand for power in developing countries combined with concerns about carbon emissions from coal-fired power plants in developed countries have created a bonanza for carbon-light technologies, including nuclear, renewables and natural gas plants. This, in turn, has put upward pressure on the price of natural gas in key markets while resulting in shortages in critical components for building renewables and nuclear reactors. Globalization of the power industry means that pressures in one segment or one region translate into shortages and rising prices everywhere else.

  3. The Rise of Blog Nation

    ERIC Educational Resources Information Center

    Lum, Lydia

    2005-01-01

    This article reports on the growth of blogs in popular culture, and the fact that they are becoming more widely accepted in the media industry. The rise and popularity of blogs--short for "Web logs"--are causing journalism educators to overhaul their teachings. In fact, blogging's influence varies from one university program to the next, just like…

  4. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

    In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

  5. Temperature rise of installed FCC

    NASA Technical Reports Server (NTRS)

    Hankins, J. D.

    1976-01-01

    Report discusses temperature profiles of installed FCC for wood and tile surfaces. Three-conductor FCC was tested at twice nominal current-carrying capacity over bare floor and under carpet, with result indicating that temperature rise is not a linear function of current with FCC at this level.

  6. What's Behind Rising Insurance Costs?

    ERIC Educational Resources Information Center

    Adams, Velma A.

    1970-01-01

    Rising risks, and losses resulting from civil disorders and vandalism are producing a squeeze on profits thus precipitating higher property insurance rates and deductibles, according to the insurance industry; while schoolmen lay the blame on industry panic. The conclusion is that school and insurance representatives must work together toward the…

  7. Rise Heights of Lazy Fountains

    NASA Astrophysics Data System (ADS)

    Hunt, Gary

    2005-11-01

    The initial rise height zm of turbulent Boussinesq fountains is determined analytically for small and large source Froude numbers Fr0. Solutions were obtained after recasting the plume conservations equations of Morton, Taylor & Turner (1956) in terms of the inverse square of a local Froude number and a local dimensionless fountain width. For large Fr0, the fountain is `forced' and the well-established linear increase of the rise height with Fr0 is obtained, i.e. zm/r0˜Fr0; r0 denoting the source radius. However, for small Fr0 the fountain is `lazy' and the dependence zm/r0˜Fr0^2 more sensitive. Additionally, the rise height for lazy fountains is predicted to be independent of the entrainment coefficient α. Comparison of our solutions with existing experimental and numerical results of fountain rise height, as well as with our own experimental results, show good agreement and support the derived scalings. Experimental results suggest that the entrainment coefficient for highly-forced fountains is αf 0.058, i.e. closer to that of a jet than of a plume. Morton, B. R., Taylor, G. I. & Turner, J. S. (1956), "Turbulent gravitational convection from maintained and instantaneous sources", Proc. Roy. Soc. A 234, 1-23.

  8. Capillary rise with velocity-dependent dynamic contact angle.

    PubMed

    Popescu, M N; Ralston, J; Sedev, R

    2008-11-04

    The classic description of the rate of capillary rise given by the Washburn equation, which assumes that the contact angle preserves the equilibrium value at all times, has been recently questioned in the light of the known experimental dependence of the dynamic contact angle on the velocity of the contact line. For a number of such proposed functions of velocity for the dynamic contact angle, we analyze the resulting dependences of the contact angle and of the time of rise, respectively, on the height of the capillary rise. By applying our results to the particular cases of a high-viscosity silicone oil and water, respectively, in a glass capillary, we show that, in general, strong similarities arise between the various approaches and the classic theory in what concerns the time dependence of the capillary rise, which explains the lack of consistent experimental evidence for deviations in the rate of capillary rise from the Washburn equation. However, for a strong dependency of the contact angle on the velocity in the range of small velocities, as in the case of water on glass, one of the models predicts significant deviations even for the time dependence of the capillary rise. Moreover, our results show that the time or height dependence of the contact angle during the capillary rise can clearly discriminate between the various models.

  9. Capillary rise in cellulose sponges

    NASA Astrophysics Data System (ADS)

    Kim, Jungchul; Kim, Ho-Young; Mahadevan, L.

    2011-11-01

    A cellulose sponge, commonly used for clean-up jobs, can absorb and hold a significant amount of water within its pores, whose size ranges from micrometers to millimeters. We investigate the dynamics of capillary rise of water in the sponge using a combination of experiment and theory. We find that the rate of the capillary rise is significantly lower than Washburn's rule that assumes the sponge as a row of adjoined pores and the liquid flow to be driven by the Laplace pressure. We introduce a novel theory to model the flow in the hygroscopic porous media by combining Darcy's law based on the moisture concentration and the modified Young-Laplace equation. The scaling law constructed through this work agrees well with the experimental results.

  10. China’s Peaceful Rise

    DTIC Science & Technology

    2014-05-20

    mixed message on the issue, the Chinese state will indeed rise peacefully. A.F.K Organski’s Power Transition international relations theory provides...A.F.K Organski’s Power Transition international relations theory provides a substantive, predictive backdrop to Chinese intent and helps characterize...Zheng’s proposal gained credence in political circles when Mr. Hu and Premier Wen Jiabao repeated this language in speeches shortly thereafter. Though

  11. Falling and Rising in Water

    ERIC Educational Resources Information Center

    Mohazzabi, Pirooz

    2010-01-01

    When an object is immersed in a liquid and released, it may sink to the bottom or rise to the surface and float. If the object's density is greater than that of the liquid, it sinks. If the object's density is less than the density of the liquid, it floats. In the special case when the object's density matches the density of the liquid, it will…

  12. Towards real-time identification of cosmic rays with LOw-Frequency ARray radio antennas

    NASA Astrophysics Data System (ADS)

    Bonardi, Antonio; Buitink, Stijn; Corstanje, Arthur; Enriquez, J. Emilio; Falcke, Heino; Hörandel, Jörg R.; Mitra, Pragati; Mulrey, Katie; Nelles, Anna; Rachen, Jörg Paul; Rossetto, Laura; Schellart, Pim; Scholten, Olaf; Thoudam, Satyendra; Trinh, Gia; ter Veen, Sander; Winchen, Tobias

    2017-03-01

    Cosmic rays entering the Earth's atmosphere produce Extensive Air Showers, which emit a radio signal through Geo-magnetic radiation and Askaryan emission. At the present time, one of the biggest challenges for assessing the Radio detection as a valuable technique for Cosmic-ray observation is to identify in real-time the very short (less than 100 ns) radio signals over the background noise. In this work, we present the latest updates on the real-time identification of radio signals from Extensive Air Showers by using the data from LOFAR Low Band Antenna stations, which are sensitive in the 30-80 MHz region.

  13. The Marion and Bouvet Rises: Remelting Gondwana's Mantle

    NASA Astrophysics Data System (ADS)

    Dick, H. J.; Zhou, H.; Standish, J. J.

    2014-12-01

    Major, trace element and isotopic data along the SW Indian Ridge identify two major geochemical provinces centered on the Marion and Bouvet Hotspots with prominent correlations between the isotopic and major element composition of basalts, ridge depth, and mineralogy of spatially associated mantle peridotites. Both consist of axial rises with elevated ridge topography. Both the Bouvet and Marion Hotspots have small volcanic fluxes, while the associated axial-rises contrast sharply in size and geochemistry. The Bouvet Rise is small, proportional to the size of the hotspot, while the Marion, with Iceland, is one of the two largest oceanic rises. A mantle plume associated with the Marion Hotspot is incapable of supporting the rise; rather it appears to be supported by a large region of anomalously depleted mantle1. The Bouvet Plume, which likely originates above the mantle transition zone, appears to have had a direct control on the geometry of the western SWIR through time and thus likely does support the short Bouvet Rise. The bathymetric contrast between these two rises corresponds to notable differences in isotopic geochemistry: while the Marion Rise basalts exhibit a complex pattern of variability - it is a region where the classic 'Dupal' anomaly is well expressed, consistent with a major Archean mantle source that likely represents delaminated metasomatized sub-continental lithosphere entrained in the shallow mantle beneath the Ridge during formation of the central and SW Indian Ridges with the breakup of Gondwana. This is supported by a similar isotopic anomaly along the Rodriguez Rise on the Central Indian Ridge that also appears related to Gondwana breakup. By contrast, the mantle beneath the Bouvet Rise appears to represent largely post-Archean asthenosphere pulled from beneath the Gondwana lithosphere, interacting with a local small plume reflecting a local heterogeneity in the upper mantle. 1. Zhou, H.-y., Dick, H.J.B., 2013. Thin crust as evidence for

  14. Rise, stagnation, and rise of Danish women's life expectancy.

    PubMed

    Lindahl-Jacobsen, Rune; Rau, Roland; Jeune, Bernard; Canudas-Romo, Vladimir; Lenart, Adam; Christensen, Kaare; Vaupel, James W

    2016-04-12

    Health conditions change from year to year, with a general tendency in many countries for improvement. These conditions also change from one birth cohort to another: some generations suffer more adverse events in childhood, smoke more heavily, eat poorer diets, etc., than generations born earlier or later. Because it is difficult to disentangle period effects from cohort effects, demographers, epidemiologists, actuaries, and other population scientists often disagree about cohort effects' relative importance. In particular, some advocate forecasts of life expectancy based on period trends; others favor forecasts that hinge on cohort differences. We use a combination of age decomposition and exchange of survival probabilities between countries to study the remarkable recent history of female life expectancy in Denmark, a saga of rising, stagnating, and now again rising lifespans. The gap between female life expectancy in Denmark vs. Sweden grew to 3.5 y in the period 1975-2000. When we assumed that Danish women born 1915-1945 had the same survival probabilities as Swedish women, the gap remained small and roughly constant. Hence, the lower Danish life expectancy is caused by these cohorts and is not attributable to period effects.

  15. Facing up to sea rise.

    PubMed

    Pernetta, J

    1994-01-01

    A milder and less extreme climate, abundance of fish and mollusks, transport and communication, and fertile land at low altitudes have drawn humans to coastal areas and river valleys for centuries. More than 60% of the world's population occupy the 150 km closest to the coast. Millions of tourists come to coastlines and small tropical islands for recreation. About 80% of the global fish supply originates from the 19 km closest to the shore. Fish are the only protein source for the rapidly growing populations in many developing countries. Global climate change is increasing the sea level so much that by 2050, the mean increase will be about 38 cm (24-52 cm). The Intergovernmental Panel on Climate Change (IPCC) notes that the effects of sea level rise will differ from place to place. Direct effects are flooding of low-lying coastal areas and increased erosion rates. An indirect effect includes higher water tables and intrusion of saline water into aquifers, resulting in loss of fresh ground water resources. These effects may make coastal areas less suitable for settlement and agriculture. Coral sand settled on top of coral reefs makes up the unstable, small atoll islands of the Pacific and Indian Oceans. People on these islands depend almost entirely on the sea for their livelihood and on the small amount of fresh water with which they grow root crops and drink. Rising sea levels also threaten low lying countries, e.g., Bangladesh, and densely populated deltas, e.g., the Nile. Changes in the frequency and severity of flooding will increase Bangladesh's dependence on foreign aid. IPCC sees 3 possible responses to the rising sea level: defense, retreat, and accommodation. Accommodation is the only practical choice for many developing countries. A switch from rice cultivation to mariculture of prawns and fish is an example of accommodation. We need to more completely understand the natural processes in coastal environments to be better prepared for climate change.

  16. Martian Heat on the Rise

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph shows that the atmospheric temperatures above the surface of Mars at Gusev Crater, Mars Exploration Rover Spirit's landing site, fluctuate to a significant degree. The color red denotes warmer temperatures, while blue is cooler. The red and yellow waves of color represent thermals, or pockets of heat, which rise and fall across the surface. These data, acquired by the rover's miniature thermal emission spectrometer, help scientists understand how the bottom layer of air closest to the surface behaves and interacts with global winds.

  17. Drainage in a rising foam.

    PubMed

    Yazhgur, Pavel; Rio, Emmanuelle; Rouyer, Florence; Pigeonneau, Franck; Salonen, Anniina

    2016-01-21

    Rising foams created by continuously blowing gas into a surfactant solution are widely used in many technical processes, such as flotation. The prediction of the liquid fraction profile in such flowing foams is of particular importance since this parameter controls the stability and the rheology of the final product. Using drift flux analysis and recently developed semi-empirical expressions for foam permeability and osmotic pressure, we build a model predicting the liquid fraction profile as a function of height. The theoretical profiles are very different if the interfaces are considered as mobile or rigid, but all of our experimental profiles are described by the model with mobile interfaces. Even the systems with dodecanol are well known to behave as rigid in forced drainage experiments. This is because in rising foams the liquid fraction profile is fixed by the flux at the bottom of the foam. Here the foam is wet with higher permeability and the interfaces are not in equilibrium. These results demonstrate once again that it is not only the surfactant system that controls the mobility of the interface, but also the hydrodynamic problem under consideration. For example liquid flow through the foam during generation or in forced drainage is intrinsically different.

  18. Diagnostics from three rising submillimeter bursts

    NASA Astrophysics Data System (ADS)

    Zhou, Ai-Hua; Li, Jian-Ping; Wang, Xin-Dong

    2016-02-01

    In this paper we investigate three novel rising submillimeter (THz) bursts that occurred sequentially in Super Active Region NOAA 10486. The average rising rate of the flux density above 200 GHz is only 20 sfu GHz-1 (corresponding to spectral index α of 1.6) for the THz spectral components of the 2003 October 28 and November 4 bursts, but it attained values of 235 sfu GHz-1 (α = 4.8) in the 2003 November 2 burst. The steeply rising THz spectrum can be produced by a population of highly relativistic electrons with a low-energy cutoff of 1 MeV, but it only requires a low-energy cutoff of 30 keV for the two slowly rising THz bursts, via gyrosynchrotron (GS) radiation based on our numerical simulations of burst spectra in the magnetic dipole field case. The electron density variation is much larger in the THz source than in the microwave (MW) source. It is interesting that the THz source radius decreased by 20%-50% during the decay phase for the three events, but the MW source increased by 28% for the 2003 November 2 event. In the paper we will present a formula that can be used to calculate the energy released by ultrarelativistic electrons, taking the relativistic correction into account for the first time. We find that the energy released by energetic electrons in the THz source exceeds that in the MW source due to the strong GS radiation loss in the THz range, although the modeled THz source area is 3-4 orders smaller than the modeled MW source one. The total energies released by energetic electrons via the GS radiation in radio sources are estimated, respectively, to be 5.2 × 1033, 3.9 × 1033 and 3.7 × 1032 erg for the October 28, November 2 and 4 bursts, which are 131, 76 and 4 times as large as the thermal energies of 2.9 × 1031, 2.1 × 1031 and 5.2 × 1031 erg estimated from soft X-ray GOES observations.

  19. A composition analyzer for microparticles using a spark ion source. [using time of flight spectrometers

    NASA Technical Reports Server (NTRS)

    Auer, S. O.; Berg, O. E.

    1975-01-01

    Iron microparticles were fired onto a capacitor-type microparticle detector which responded to an impact with a spark discharge. Ion currents were extracted from the spark and analyzed in a time-of-flight mass spectrometer. The mass spectra showed the element of both detector and particle materials. The total extracted ion currents was typically 10A within a period of 100ns, indicating very efficient vaporization of the particle and ionization of the vapor. Potential applications include research on cosmic dust, atmospheric aerosols and cloud droplets, particles ejected by rocket or jet engines, by machining processes, or by nuclear bomb explosions.

  20. Vector Brillouin optical time-domain analyzer for high-order acoustic modes.

    PubMed

    Dossou, Michel; Bacquet, Denis; Szriftgiser, Pascal

    2010-11-15

    Thanks to a double-frequency phase modulation scheme, we report a vector Brillouin optical time-domain analyzer (BOTDA). This BOTDA has a high immunity level to noise, and it features a phase spectrogram capability. It is well suited for complex situations involving several acoustic resonances, such as high-order longitudinal modes. It has notably been used to characterize a dispersion-shifted fiber, allowing us to report spectrograms with multiple acoustic resonances. A very high 57 dB dynamic range is also reported for 100-ns-long pulses simultaneously with a 16 cm numerical resolution.

  1. Simple method of measuring delay time in manufacturing delay lines

    NASA Astrophysics Data System (ADS)

    Kasahara, Yukio; Mikoda, Masanari

    1982-07-01

    A simple method for measuring delay time in an operational frequency range is required in manufacturing delay lines used for video tape recorders and television receiver sets. This paper describes a simple method of measuring and adjusting the delay time of such delay lines. The delay time is obtained by measuring a phase difference ϑ between the signals at the input and output transducers of the delay line with frequencies under test. The delay time is more precisely obtained by measuring the ϑ at a constant frequency within the bandwidth of the delay line. A delay-time tolerance of a polished glass medium at 3.58 MHz was found to be within 100 ns. The delay time was found to be shortened by 30 ns by attaching the medium on polishing powder and oil. Also shown is a simple method for adjusting the delay time by polishing a delay medium while measuring the phase difference.

  2. Pulsar timing sensitivity to very-low-frequency gravitational waves

    SciTech Connect

    Jenet, Fredrick A.; Armstrong, J. W.; Tinto, Massimo

    2011-04-15

    We compute the sensitivity, constrained by instrumental, propagation, and other fundamental noises, of pulsar timing to very-low-frequency gravitational waves (GWs). Reaching predicted GW signal strengths will require suppression of time-of-arrival fluctuations caused by interstellar plasma turbulence and a reduction of white rms timing noise to < or approx. 100 ns. Assuming negligible intrinsic pulsar rotational noise, perfect time transfer from time standard to observatory, and stable pulse profiles, the resulting single-pulsar signal-to-noise ratio=1 sensitivity is limited by terrestrial time standards at h{sub rms}{approx}2x10{sup -16} [f/ (1 cycle/year)]-1/2 for f<3x10{sup -8} Hz, where f is the Fourier frequency and a bandwidth of 1 cycle/(10 years) is assumed. Since this sensitivity is comparable to predicted GW signal levels, a reliable detection will require substantial signal-to-noise ratio improvement via pulsar timing array.

  3. Large Volcanic Rises on Venus

    NASA Technical Reports Server (NTRS)

    Smrekar, Suzanne E.; Kiefer, Walter S.; Stofan, Ellen R.

    1997-01-01

    Large volcanic rises on Venus have been interpreted as hotspots, or the surface manifestation of mantle upwelling, on the basis of their broad topographic rises, abundant volcanism, and large positive gravity anomalies. Hotspots offer an important opportunity to study the behavior of the lithosphere in response to mantle forces. In addition to the four previously known hotspots, Atla, Bell, Beta, and western Eistla Regiones, five new probable hotspots, Dione, central Eistla, eastern Eistla, Imdr, and Themis, have been identified in the Magellan radar, gravity and topography data. These nine regions exhibit a wider range of volcano-tectonic characteristics than previously recognized for venusian hotspots, and have been classified as rift-dominated (Atla, Beta), coronae-dominated (central and eastern Eistla, Themis), or volcano-dominated (Bell, Dione, western Eistla, Imdr). The apparent depths of compensation for these regions ranges from 65 to 260 km. New estimates of the elastic thickness, using the 90 deg and order spherical harmonic field, are 15-40 km at Bell Regio, and 25 km at western Eistla Regio. Phillips et al. find a value of 30 km at Atla Regio. Numerous models of lithospheric and mantle behavior have been proposed to interpret the gravity and topography signature of the hotspots, with most studies focusing on Atla or Beta Regiones. Convective models with Earth-like parameters result in estimates of the thickness of the thermal lithosphere of approximately 100 km. Models of stagnant lid convection or thermal thinning infer the thickness of the thermal lithosphere to be 300 km or more. Without additional constraints, any of the model fits are equally valid. The thinner thermal lithosphere estimates are most consistent with the volcanic and tectonic characteristics of the hotspots. Estimates of the thermal gradient based on estimates of the elastic thickness also support a relatively thin lithosphere (Phillips et al.). The advantage of larger estimates of

  4. Geochemistry and age of Shatsky, Hess, and Ojin Rise seamounts: Implications for a connection between the Shatsky and Hess Rises

    NASA Astrophysics Data System (ADS)

    Tejada, Maria Luisa G.; Geldmacher, Jörg; Hauff, Folkmar; Heaton, Daniel; Koppers, Anthony A. P.; Garbe-Schönberg, Dieter; Hoernle, Kaj; Heydolph, Ken; Sager, William W.

    2016-07-01

    Shatsky Rise in the Northwest Pacific is the best example so far of an oceanic plateau with two potential hotspot tracks emanating from it: the linear Papanin volcanic ridge and the seamounts comprising Ojin Rise. Arguably, these hotspot tracks also project toward the direction of Hess Rise, located ∼1200 km away, leading to speculations that the two plateaus are connected. Dredging was conducted on the massifs and seamounts around Shatsky Rise in an effort to understand the relationship between these plateaus and associated seamounts. Here, we present new 40Ar/39Ar ages and trace element and Nd, Pb, and Hf isotopic data for the recovered dredged rocks and new trace elements and isotopic data for a few drill core samples from Hess Rise. Chemically, the samples can be subdivided into plateau basalt-like tholeiites and trachytic to alkalic ocean-island basalt compositions, indicating at least two types of volcanic activity. Tholeiites from the northern Hess Rise (DSDP Site 464) and the trachytes from Toronto Ridge on Shatsky's TAMU massif have isotopic compositions that overlap with those of the drilled Shatsky Rise plateau basalts, suggesting that both Rises formed from the same mantle source. In contrast, trachytes from the southern Hess Rise (DSDP Site 465A) have more radiogenic Pb isotopic ratios that are shifted toward a high time-integrated U/Pb (HIMU-type mantle) composition. The compositions of the dredged seamount samples show two trends relative to Shatsky Rise data: one toward lower 143Nd/144Nd but similar 206Pb/204Pb ratios, the other toward similar 143Nd/144Nd but more radiogenic 206Pb/204Pb ratios. These trends can be attributed to lower degrees of melting either from lower mantle material during hotspot-related transition to plume tail or from less refractory shallow mantle components tapped during intermittent deformation-related volcanism induced by local tectonic extension between and after the main volcanic-edifice building episodes on Shatsky

  5. Temperature rise in superfluid helium pumps

    SciTech Connect

    Kittel, P.

    1988-07-01

    The temperature rise of a fountain effect pump (FEP) and of a centrifugal pump (CP) are compared. Calculations and estimates presented here show that under the operating conditions expected during the resupply of superfluid helium in space, a centrifugal pump will produce a smaller temperature rise than will a fountain effect pump. The temperature rise for the FEP is calculated assuming an ideal pump, while the temperature rise of the CP is estimated from the measured performance of a prototype pump. As a result of this smaller temperature rise and of the different operating characteristics of the two types of pumps, transfers will be more effective using a centrifugal pump.

  6. Temperature rise in superfluid helium pumps

    NASA Technical Reports Server (NTRS)

    Kittel, Peter

    1988-01-01

    The temperature rise of a fountain effect pump (FEP) and of a centrifugal pump (CP) are compared. Calculations and estimates presented here show that under the operating conditions expected during the resupply of superfluid helium in space, a centrifugal pump will produce a smaller temperature rise than will a fountain effect pump. The temperature rise for the FEP is calculated assuming an ideal pump, while the temperature rise of the CP is estimated from the measured performance of a prototype pump. As a result of this smaller temperature rise and of the different operating characteristics of the two types of pumps, transfers will be more effective using a centrifugal pump.

  7. Instability of two rising bubbles

    NASA Astrophysics Data System (ADS)

    Galper, Alexander; Miloh, Touvia

    1999-11-01

    We consider the stability of two rising ideal gas spherical bubbles subject of an intrinsic dynamics. The dynamics is prescribed or governed by the Rayleigh-Plesset equation adjusted for the pressure field induced by the other bubble in the center of each. Hence, each bubble exhibits linear (nonlinear) oscillations about a stable equilibrium. In order to treat the Liapunov stability problem of bubbles spatial motion we develop the corresponding Hamiltonian formalism. Thus, we find that the oscillations can stabilize the side-by-side and one-below-the-other bubbles translation. These types of translation are known to be asymptotically stable (unstable) for the motion of a pair of purely spherical rigid bubbles. The stabilization phenomenon depends on the frequency and phase difference in the bubbles fast oscillations. The ``rigid'' bubbles theory of the motion is known to have certain discrepancies with the relevant experiments. In order to remove them it is proposed to account for the vorticity wake behind each bubble. Nevertheless, we are able to explain the experiments remaining within the potential framework. Finally, we consider the case of chaotic pulsations. The motion of the two bubbles can also inherit a chaotic character. It results, in turn, in a certain strange attractor for the spatial motion of a pair.

  8. The rise of Astyanax cavefish

    PubMed Central

    Gross, Joshua B.; Meyer, Bradley; Perkins, Molly

    2015-01-01

    Numerous animals have invaded subterranean caverns and evolved remarkably similar features. These features include loss of vision and pigmentation, and gains in non-visual sensation. This broad convergence echoes smaller-scale convergence, in which members of the same species repeatedly evolve the same cave-associated phenotypes. The blind Mexican tetra of the Sierra de El Abra region of northeastern Mexico has a complex origin, having recurrently colonized subterranean environments through numerous invasions of surface-dwelling fish. These colonizations likely occurred ~1–5 MYa. Despite evidence of historical and contemporary gene flow between cave and surface forms, the cave-associated phenotype appears to remain quite stable in nature. This model system has provided insight to the mechanisms of phenotypic regression, the genetic basis for constructive trait evolution, and the origin of behavioral novelties. Here, we document the rise of this model system from its discovery by a Mexican surveyor in 1936, to a powerful system for cave biology and contemporary genetic research. The recently sequenced genome provides exciting opportunities for future research, and will help resolve several long-standing biological problems. PMID:25601346

  9. Time and space resolved measurement of the electron temperature, mass density and ionization state in the ablation plasma between two exploding Al wiresa)

    NASA Astrophysics Data System (ADS)

    Knapp, P. F.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Hansen, S. B.

    2012-05-01

    We have determined the properties of plasma around and between two exploding wires using high-resolution x-ray absorption spectroscopy. Plasma densities and temperatures ranging from ≳0.1g/cm3 and a few eV to less than 0.01 g/cm3 and 30 eV have been measured in experiments at Cornell University with two 40 μm aluminum (Al) wires spaced 1 mm apart driven by ˜150 kA peak current pulses with 100 ns rise time. The wire plasma was backlit by the 1.4-1.6 keV continuum radiation produced by a Mo wire X-pinch. The spectrometer employed two spherically bent quartz crystals to record the absorption and backlighter spectra simultaneously. The transition between the dense Al wire core and the coronal plasma is seen as a transition from cold K-edge absorption to Mg-, Na-, and finally Ne-like absorption at the boundary. In the plasma that accumulates between the wires, ionization states up to C-Like Al are observed. The spectrometer geometry and ˜2μm X-pinch source size provide 0.3 eV spectral resolution and 20 μm spatial resolution enabling us to see 1s → 2p satellite transitions as separate lines as well as O-, F-, and Ne-like 1s → 3p transitions that have not been seen before. A step wedge was used to calibrate the transmission, enabling density to be measured within a factor of two and temperature to be measured within ±25%. A genetic algorithm was developed to fit synthetic spectra calculated using the collisional-radiative code SCRAM to the experimental spectra. In order to obtain agreement it was necessary to assume multiple plasma regions with variable thicknesses, thereby allowing the inferred plasma conditions to vary along the absorption path.

  10. Influence of Resistance Method on Motor Winding Temperature Rise Measurement

    NASA Astrophysics Data System (ADS)

    Beges, G.

    2011-12-01

    The objective of this article is presentation of influences when measuring the motor winding temperature rise in the scope of safety testing of electrical appliances, with respect to conformity assessment. The temperature measurement in testing is one of the most defined fields of measurement, but it is very important how the measurement is performed. Standards only describe that the resistance method shall be used for determination of the temperature rise (heating) of the winding. The temperature rise is defined as the average temperature rise of the windings above the ambient (surrounding) temperature, at the specified load of the unit under test. It is not explicitly defined how to approach this measurement when using cooling characteristics of the winding for determination of the temperature rise. Since the extrapolation curve is used, the procedure is also very important to obtain a result as accurate as possible. It is important that measurement results and their associated uncertainties are correctly evaluated, and on that basis, appropriate conclusions of conformity of the product with specifications are made. The resistance method influence on the motor winding temperature rise measurement is a case study in this article. The article focuses on the measurement of the temperature rise of electrical motors used in electrical appliances according to the standard EN 60335-1, clause 11 (2002) (identical as standard IEC 60335-1, 2001). In this article, the influencing parameters are analyzed when measuring the temperature rise of electromotor winding. As a case study, concrete measurements are presented. The optimal time after which the performer has to start measurement of the cooling characteristics is analyzed, since the motors are typically mounted deep into appliances. Especially for a collector motor winding, it takes some time for a performer to be able to connect the measuring instrument to collector's lamellas because this contact has an important

  11. Slow-rise and Fast-rise Phases of an Erupting Solar Filament and Flare Emission Onset

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.

    2005-01-01

    We observe the eruption of an active-region solar filament of 1998 July 11 using high time cadence and high spatial resolution EUV observations from the TRACE satellite, along with soft X-ray images from the soft X-ray telescope (SXT) on the Yohkoh satellite, hard X-ray fluxes from the BATSE instrument on the Compton Gamma Ray Observatory (CGRO) satellite and from the hard X-ray telescope (HXT) on Yohkoh, and ground-based magnetograms. We concentrate on the initiation of the eruption in an effort to understand the eruption mechanism. Prior to eruption the filament undergoes slow upward movement in a "slow rise" phase with an approximately constant velocity of about 15 km/s that lasts about 10 min. It then erupts in a "fast-rise" phase, accelerating to a velocity of about 200 km/s in about 5 min, and then decelerating to approximately 150 km/s over the next 5 min. EUV brightenings begin about concurrent with the start of the filament's slow rise, and remain immediately beneath the rising filament during the slow rise; initial soft X-ray brightenings occur at about the same time and location. Strong hard X-ray emission begins after the onset of the fast rise, and does not peak until the filament has traveled to a substantial altitude (to a height about equal to the initial length of the erupting filament) beyond its initial location. Additional information is available in the original extended abstract.

  12. Analysis of Recent Major Outer-Rise Earthquake Rupture Characteristics

    NASA Astrophysics Data System (ADS)

    Cleveland, M.; Ammon, C.; Lay, T.; Kanamori, H.

    2009-12-01

    Outer-rise earthquakes can help indicate the degree of seismic coupling of a subduction zone megathrust as well help constrain stress transfer processes in underthrusting oceanic lithosphere during the seismic cycle. In addition, outer rise earthquake-related structures may play a significant role in the transport of water into subduction zones, and possibly provide seismogenic structures re-activated during intermediate-depth earthquakes. And finally, although less frequent than large underthrusting events, large outer-rise earthquakes may pose significant hazard since they have been found to display higher stress drops and greater enrichment in high frequency shaking than comparable size interplate events. In this study we analyze and compare the seismic properties of three specific outer-rise sequences, representing relatively diverse tectonic characteristics, including events from southern Vanuatu (formerly New Hebrides), central Kuril Islands, and the Andaman Islands regions. Similar to several important historic events, these recent large outer rise sequences provide information on the transmission of slab-pull generated stresses and their relationship with large underthrusting earthquakes. To allow comparison with the 13 January (Mw 8.1) 2007 central Kuril Islands sequence that we studied previously, we conduct finite-fault analyses of the 16 May, 1995 Vanuatu, Mw = 7.7 and 10 August, 2009 Andaman Islands, Mw = 7.5, outer-rise events using azimuthally distributed teleseismic P and SH waveforms and Rayleigh-wave effective source time functions. The unique tectonic geometry of the Vanuatu event, occurring near the corner of the overriding Pacific Plate, conveys information about the influence of geometry on the outer-rise character. The Andaman earthquake occurred in a region with substantially oblique plate motion where geometrical plate relationships remain somewhat unclear. Considering their seismic properties and relationship to nearby great underthrusting

  13. Time Trend Analysis of Cervical High-Risk HPV in HIV-Infected Women in an Urban Cohort from Rio de Janeiro, Brazil: The Rise of Non-16/18 HPV

    PubMed Central

    Cambou, Mary C; Levi, José Eduardo; Lake, Jordan E; de Andrade, Angela; Jalil, Emilia M; Russomano, Fabio; Derrico, Mônica; Veloso, Valdilea G; Friedman, Ruth K; Luz, Paula M; Grinsztejn, Beatriz

    2015-01-01

    Objectives HIV-infected women are at increased risk of HPV infection. We assessed time trends in annual prevalences of cervical high-risk human papillomavirus (HR-HPV) genotypes from 2006-2012 among a non-vaccinated, HIV-infected female cohort in urban Brazil. Study Design Cervical specimens for HPV genotyping were collected yearly between January 2006 and December 2012 in a cross-sectional analysis of participants ≥18 years enrolled in the Women’s HIV Cohort at Fiocruz in Rio de Janeiro, Brazil. Age-adjusted generalized estimating equation models with an exchangeable matrix were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for annual HPV positivity (reference year: 2006). Results Among 590 participants: median age 35.5-40.0 from 2006-2012; any HR-HPV prevalence ≥53% every year; HR-HPV 16, 58, 59, and 68 prevalences ≥24% in at least one year. Odds of HPV 16 and 68 decreased in 2012. HPV 58 prevalences followed a U-shape, beginning and ending with >20%. HPV 59 prevalences followed a linear trend, with increased odds in 2012 (OR 16.0, 95% CI [3.8 – 67.3], Bonferroni-adjusted p-value<0.01). Conclusions The prevalences of HR-HPV 58, 59 and 68 were high in this cohort. Given current HR-HPV vaccine coverage and availability, further investigation is needed to optimize vaccine recommendations for this population. PMID:26518062

  14. Excitation of parasitic modes in gyrotrons with fast voltage rise

    SciTech Connect

    Nusinovich, G. S.; Antonsen, T. M. Jr.; Vlasov, A. N.; Lohr, J.; Danly, B. G.; Hogge, J.-P.

    2008-10-15

    Megawatt-class, long-pulse and continuous-wave gyrotrons operate in high-order modes in order to handle the thermal losses in the resonators. The spectral density of neighboring modes in these devices is high; consequently during the beam voltage rise parasitic modes can be excited. If such gyrotrons are used in plasma experiments, these parasites can be dangerous for the receiving channels of numerous diagnostic tools. It is shown that in gyrotrons utilizing diode-type magnetron injection guns the shortening of the voltage rise time to about one microsecond can practically eliminate excitation of parasitic modes even in devices with a 2 MW power level. Some means for realizing such rise times in high-voltage modulators which can be used for megawatt-class gyrotrons are discussed. It is also shown that allowable beam voltage overshoot in such gyrotrons is about 2.5%.

  15. The Rise of the CISO

    ERIC Educational Resources Information Center

    Gale, Doug

    2007-01-01

    The late 1980s was an exciting time to be a CIO in higher education. Computing was being decentralized as microcomputers replaced mainframes, networking was emerging, and the National Science Foundation Network (NSFNET) was introducing the concept of an "internet" to hundreds of thousands of new users. Security wasn't much of an issue;…

  16. Analysis of Recombination in CdTe Heterostructures With Time-Resolved Two-Photon Excitation Microscopy

    SciTech Connect

    Kuciauskas, Darius; Wernsing, Keith; Jensen, Soren Alkaersig; Barnes, Teresa M.; Myers, Thomas H.; Bartels, Randy A.

    2016-11-01

    Here, we used time-resolved photoluminescence microscopy to analyze charge carrier transport and recombination in CdTe double heterostructures fabricated by molecular beam epitaxy (MBE). This allowed us to determine the charge carrier mobility in this system, which was found to be 500-625 cm2/(V s). Charge carrier lifetimes in the 15-100 ns range are limited by the interface recombination, and the data indicate higher interface recombination velocity near extended defects. This study describes a new method to analyze the spatial distribution of the interface recombination velocity and the interface defects in semiconductor heterostructures.

  17. Analysis of Recombination in CdTe Heterostructures With Time-Resolved Two-Photon Excitation Microscopy

    DOE PAGES

    Kuciauskas, Darius; Wernsing, Keith; Jensen, Soren Alkaersig; ...

    2016-11-01

    Here, we used time-resolved photoluminescence microscopy to analyze charge carrier transport and recombination in CdTe double heterostructures fabricated by molecular beam epitaxy (MBE). This allowed us to determine the charge carrier mobility in this system, which was found to be 500-625 cm2/(V s). Charge carrier lifetimes in the 15-100 ns range are limited by the interface recombination, and the data indicate higher interface recombination velocity near extended defects. This study describes a new method to analyze the spatial distribution of the interface recombination velocity and the interface defects in semiconductor heterostructures.

  18. A modified infrared spectrometer with high time resolution and its application for investigating fast conformational changes of the GTPase Ras.

    PubMed

    Lin, Jie; Gerwert, Klaus; Kötting, Carsten

    2014-01-01

    Time-resolved infrared spectroscopy is a valuable tool for the investigation of proteins and protein interactions. The investigation of many biological processes is possible by means of caged compounds, which set free biologically active substances upon light activation. Some caged compounds could provide sub-nanosecond time resolution, e.g., para-hydroxyphenacyl-guanosine 5'-triphosphate (GTP) forms GTP in picoseconds. However, the time resolution in single shot experiments with rapid-scan Fourier transform infrared (FT-IR) spectrometers is limited to about 10 ms. Here we use an infrared diode laser instead of the conventional globar and achieve a time resolution of 100 ns. This allows for the time-resolved measurement of the fast Ras(off) to Ras(on) conformational change at room temperature. We quantified the activation parameters for this reaction and found that the free energy of activation for this reaction is mainly enthalpic. Investigation of the same reaction in the presence of the Ras binding domain of the effector Raf (RafRBD) reveals a four orders of magnitude faster reaction, indicating that Ras·RafRBD complex formation directly induces the conformational change. Recent developments of broadly tunable quantum cascade lasers will further improve time resolution and usability of the setup. The reported 100 ns time resolution is the best achieved for a non-repetitive experiment so far.

  19. An improved microfluidics approach for monitoring real-time interaction profiles of ultrafast molecular recognition

    NASA Astrophysics Data System (ADS)

    Batabyal, Subrata; Rakshit, Surajit; Kar, Shantimoy; Pal, Samir Kumar

    2012-04-01

    Our study illustrates the development of a microfluidics (MF) platform combining fluorescence microscopy and femtosecond/picosecond-resolved spectroscopy to investigate ultrafast chemical processes in liquid-phase diffusion-controlled reactions. By controlling the flow rates of two reactants in a specially designed MF chip, sub-100 ns time resolution for the exploration of chemical intermediates of the reaction in the MF channel has been achieved. Our system clearly rules out the possibility of formation of any intermediate reaction product in a so-called fast ionic reaction between sodium hydroxide and phenolphthalein, and reveals a microsecond time scale associated with the formation of the reaction product. We have also used the developed system for the investigation of intermediate states in the molecular recognition of various macromolecular self-assemblies (micelles) and genomic DNA by small organic ligands (Hoechst 33258 and ethidium bromide). We propose our MF-based system to be an alternative to the existing millisecond-resolved "stopped-flow" technique for a broad range of time-resolved (sub-100 ns to minutes) experiments on complex chemical/biological systems.

  20. BUNCH PATTERNS AND PRESSURE RISE IN RHIC.

    SciTech Connect

    FISCHER,W.IRISO-ARIZ,U.

    2004-07-05

    The RHIC luminosity is limited by pressure rises with high intensity beams. At injection and store, the dominating cause for the pressure rise was shown to be electron clouds. We discuss bunch distributions along the circumference that minimize the electron cloud effect in RHIC. Simulation results are compared with operational observations.

  1. 21 CFR 137.180 - Self-rising flour.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., self-rising wheat flour, is an intimate mixture of flour, sodium bicarbonate, and one or more of the... by means of the leveling bulb E bring the displacement solution to the 25 cc. graduation above the... burette into the air, keep the displacement solution in the leveling bulb at all times during...

  2. Temperature rise during photoradiation therapy of malignant tumors

    SciTech Connect

    Svaasand, L.O.; Doiron, D.R.; Dougherty, T.J.

    1983-01-01

    This report discusses the optical and thermal distribution during photoradiation therapy of malignant tumors. Emphasis is put on the therapeutic procedure with the light dose delivered through an inserted optical fiber. Theoretical predictions and experimental results indicate that the temperature rise during the procedure may give rise to hyperthermal cell kill. The report discusses the extent of the regions with hyperthermal bioeffects in terms of tissue parameters as optical absorption and scattering, thermal conductivity, specific heat, blood flow, and optical dose parameters as optical power and exposure time. Key words: photoradiation therapy, hematoporphyrin derivative, hyperthermia

  3. Research on fast rise time EMP radiating-wave simulator

    NASA Astrophysics Data System (ADS)

    Fan, Lisi; Liu, Haitao; Wang, Yun

    2013-03-01

    This paper presents an antenna of High altitude electromagnetic pulse (HEMP) radiating-wave simulator which expands the testing zone larger than the traditional transmission line simulator. The numerical results show that traverse electramagnetic (TEM) antenna can be used to radiate HEMP simulation radiating wave, but in low frequency band the emissive capability is poor. The experiment proves the numerical model is valid. The results of this paper show that TEM antenna can be used to HEMP radiating-wave simulator, and can prove the low frequency radiation capability through resistance loaded method.

  4. Timescales for detecting a significant acceleration in sea level rise

    PubMed Central

    Haigh, Ivan D.; Wahl, Thomas; Rohling, Eelco J.; Price, René M.; Pattiaratchi, Charitha B.; Calafat, Francisco M.; Dangendorf, Sönke

    2014-01-01

    There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records. PMID:24728012

  5. Fertility postponement is largely due to rising educational enrolment.

    PubMed

    Ní Bhrolcháin, Máire; Beaujouan, Eva

    2012-11-01

    The rise in educational enrolment is often cited as a possible cause of the trend to later childbearing in developed societies but direct evidence of its contribution to the aggregate change in fertility tempo is scarce. We show that rising enrolment, resulting in later ages at the end of education, accounts for a substantial part of the upward shift in the mean age at first birth in the 1980s and 1990s in Britain and in France. The postponement of first birth over that period has two components: a longer average period of enrolment and a post-enrolment component that is also related to educational level. The relationship between rising educational participation and the move to later fertility timing is almost certainly causal. Our findings therefore suggest that fertility tempo change is rooted in macro-economic and structural forces rather than in the cultural domain.

  6. Timescales for detecting a significant acceleration in sea level rise.

    PubMed

    Haigh, Ivan D; Wahl, Thomas; Rohling, Eelco J; Price, René M; Pattiaratchi, Charitha B; Calafat, Francisco M; Dangendorf, Sönke

    2014-04-14

    There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records.

  7. Alkyne metathesis on the rise.

    PubMed

    Fürstner, Alois

    2013-03-04

    The early years of alkyne metathesis were marked by a somewhat ironic state of affairs: the proposed mechanism was swiftly validated and more than one effective catalyst became available shortly after the discovery of this transformation; surprisingly, however, the impact on synthesis remained very limited for a long period of time. Recent advances, however, suggest that this situation is about to change: the remarkable activity, functional-group tolerance, and reliability of the latest generation of catalysts open the door for highly advanced applications. The resulting (cyclo)alkynes are amenable to numerous postmetathetic transformations, which diversify the product portfolio and bring many different structural motifs into reach. Since the catalysts have also evolved from the glovebox to the benchtop, there should be little barrier left for a wider use of this reaction in organic synthesis.

  8. True rise in anaphylaxis incidence

    PubMed Central

    Yang, Min-Suk; Kim, Ju-Young; Kim, Byung-Keun; Park, Heung-Woo; Cho, Sang-Heon; Min, Kyung-Up; Kang, Hye-Ryun

    2017-01-01

    Abstract The incidence trend of anaphylaxis in Asia is not well investigated. The aim of this study is to estimate the entire population-based incidence of anaphylaxis in Korea using a nationwide administrative database. Data over a 7-year period (2008–2014) was obtained from the Korean National Health Insurance (NHI) claims database which covers 97.9% of the entire Korean population. Using diagnosis codes from the International Classification of Diseases-10 for anaphylaxis (T78.0, T78.2, T80.5, and T88.6), we identified the annual number of patients who had visited any hospital with a primary diagnosis of anaphylaxis. Incidence rates were calculated using the population distribution data of all NHI beneficiaries. The incidence of anaphylaxis in Korea was 32.19 episodes per 100,000 person-years in 2014, which nearly doubled from 2008 (16.02 episodes per 100,000 person-years). The incidence of anaphylaxis increased continuously throughout these years regardless of gender and age groups (P for trend < 0.001). Female was significantly less predisposed than male (adjusted odds ratio [OR], 0.69; 95% confident interval [CI], 0.66–0.72; P < 0.001). The incidence was the lowest in 0 to 19 age group and the highest in 40 to 69 age group (adjusted OR, 2.41; 95% CI, 2.29–2.54; P < 0.001). In conclusion, we report the increasing time trend of anaphylaxis incidence rates using nationwide claims database for the first time in Asia. PMID:28151851

  9. COASTAL SENSITIVITY TO SEA LEVEL RISE: A FOCUS ON ...

    EPA Pesticide Factsheets

    Synthesis and Assessment Product 4.1 will synthesize information from the ongoing mapping efforts by federal and non-federal researchers related to the implications of rising sea level. It will overlay the various data layers to develop new results made possible by bringing together researchers that are otherwise working independently. Because of time, data, and resource limitations, the synthesis will focus on a contiguous portion of the U.S. coastal zone (New York to North Carolina). The report will also develop a plan for sea level rise research to answer the questions that are most urgent for near-term decisionmaking. This report will address the implications of sea level rise on three spatial scales by providing: • A literature review that puts the report within the nationwide context. • Data overlays and a state-of-the-art quantitative assessment concerning coastal elevations, shore erosion, and wetland accretion for a multi-state study area along the U.S. Atlantic Coast: New York to North Carolina. • Qualitative discussions and case studies that document in greater detail the impact of sea level rise on smaller areas within the mid-Atlantic study area. This report will provide information that supports the specific goal in Chapter 9 of the Strategic Plan for the Climate Change Science Program (CCSP, 2003) to analyze how coastal environmental programs can be improved to adapt to sea level rise while enhancing economic growth.

  10. Recent sedimentation on the new jersey slope and rise.

    PubMed

    Stanley, D J; Nelsen, T A; Stuckenrath, R

    1984-10-12

    Radiocarbon dating and sedimentological studies of closely spaced cores indicate movement during the Holocene of sediments on the New Jersey continental slope and upper rise between Wilmington and Lindenkohl canyons. The uneven time-stratigraphic thickness of the late Quaternary sediment sections between cores and the nonuniform deposition rate at any given core site and among core sites show that the sediment blanket in canyon and intercanyon areas has been affected by downslope, gravity-driven pocesses during the Holocene to the present. The reduced rate of deposition on the slope and upper rise between the late Pleistocene and the present is largely due to decreased off-shelf transport in response to the eustatic rise in sea level. Very old radiocarbon dates at core tops result from emplacement of older reworked materials from upslope or from truncation of sections by mass wasting processes exposing older material at the sea floor. These processes also account for an irregular sequence of dated sections within cores and stratigraphic irregularities of the surficial cover from core to core. Marked variability in deposition rates on the slope and upper rise is largely a function of topographic configuration, proximity and accessibility to sediment source, and transport processes seaward of the shelf break. Moreover, higher accumulation rates on the upper rise are attributed primarily to slope bypassing. Bypassing, prevalent during the late Pleistocene, has continued periodically to the present.

  11. Preferential amplification of rising versus falling frequency whistler mode signals

    NASA Astrophysics Data System (ADS)

    Li, J. D.; Harid, V.; Spasojevic, M.; Gołkowski, M.; Inan, U. S.

    2015-01-01

    Analysis of ground-based ELF/VLF observations of injected whistler mode waves from the 1986 Siple Station experiment demonstrates the preferential magnetospheric amplification of rising over descending frequency-time ramps. From examining conjugate region receptions of ±1 kHz/s frequency-time ramps, we find that rising ramps generate an average total power 1.9 times higher than that of falling frequency ramps when both are observed during a transmission. And in 17% of receptions, only rising ramps are observed above the noise floor. Furthermore, the amplification ratio inversely correlates with the noise and total signal power. Using a narrowband Vlasov-Maxwell numerical simulation, we explore the preferential amplification due to differences in linear growth rate as a function of frequency, relative to the frequency which maximizes the linear growth rate for a given anisotropy, and in nonlinear phase trapping. These results contribute to the understanding of magnetospheric wave amplification and the preference for structured rising elements in chorus.

  12. Drivers of Pontocaspian Biodiversity Rise and Demise

    NASA Astrophysics Data System (ADS)

    Wesselingh, Frank; Flecker, Rachel; Wilke, Thomas; Leroy, Suzanne; Krijgsman, Wout; Stoica, Marius

    2015-04-01

    In the past two million years, the region of the Black Sea Basin, Caspian Basin and adjacent Anatolia and the Balkans were the stage of the evolution of a unique brackish water fauna, the so-called Pontocaspian fauna. The fauna is the result of assembly of genera with a Paratethyan origin and Anatolian origins during the Early Pleistocene. The rapid diversification of the Pontocaspian fauna is the result of the very dynamic nature of the lakes (the Caspian Sea is technically a lake) and seas in the region in the past two million years. In most times the various lake basins were isolated (like today), but in other episodes connections existed. Regional and global climate as well as the regional tectonic regimes were main drivers of lake basin evolution. Over the past 80 years a major biodiversity crisis is hitting the Pontocaspian faunas due to environmental degradation, pollution and invasive species. In the new EU-ETN PRIDE (Drivers of Pontocaspian Biodiversity Rise and Demise)we will be documenting the geological context of past diversifications and turnover events. We present examples of rapid turnover (biodiversity crises) in the Quaternary, assess driving forces and draw implications for the nature of the current human-mediated biodiversity crisis in the region.

  13. An experimental study on the rate and mechanism of capillary rise in sandstone

    NASA Astrophysics Data System (ADS)

    Tsunazawa, Yuya; Yokoyama, Tadashi; Nishiyama, Naoki

    2016-12-01

    The Lucas-Washburn equation is a fundamental expression used to describe capillary rise in geologic media on the basis of pore radius, liquid viscosity, surface tension, contact angle, and time. It is known that a radius value significantly smaller than the main pore radius must be used in the equation in order for the predictions to fit the experimentally measured values. To evaluate this gap between theoretical predictions and experimental data, we conducted several capillary rise experiments using Berea sandstone. First, to investigate conditions in which pores of any size are available for capillary rise, an experiment was conducted using a dried core. Next, to adjust the size distribution of pore water before the capillary rise, gas pressure was applied to a water-saturated core and water was expelled from pores of r > 10 μm; then, capillary rise was initiated. Under this condition, capillary rise occurred only in the pores of r > 10 μm. The same experiment was conducted for r = 3, 1, and 0.36 μm. When narrower pores were made available for capillary rise, the overall rate of rise decreased and approached the rate observed when the sample was dry initially. This observation suggests that the capillary rise in narrow pores plays a significant role in the overall rate. Based on these results, we propose a conceptual capillary rise model that considers differing radii in branched pores and provide an example of a quantitative description of capillary rise.

  14. Climate Adaptation and Sea Level Rise

    EPA Pesticide Factsheets

    EPA supports the development and maintenance of water utility infrastructure across the country. Included in this effort is helping the nation’s water utilities anticipate, plan for, and adapt to risks from flooding, sea level rise, and storm surge.

  15. Rising income and the subjective well-being of nations.

    PubMed

    Diener, Ed; Tay, Louis; Oishi, Shigehiro

    2013-02-01

    We explored whether rising income in nations is associated with increasing subjective well-being (SWB), with several advances over earlier work. Our methods are improved in that across time, the same well-being questions were asked in the same order, and we employed broad and equivalent representative samples over time from a large number of nations. We also assessed psychosocial factors that might mediate the relation of income and SWB. We found that changes in household income were associated with concomitant changes in life evaluations, positive feelings, and negative feelings. The effects of gross domestic product (GDP) change were weaker and significant only for life evaluations, perhaps because GDP was a less certain index of the standard of living of the average household. The association of income and SWB is more likely to occur when the average person's material welfare accompanies rising income, when people become more satisfied with their finances, and when people become more optimistic about their futures. People did not adapt to the income rises during the period of years we studied, in that income rises produced SWB increases that did not return to earlier levels. It appears that previous researchers failed to come to agreement because of the small sample sizes of the nations, the inconsistent methods across years and surveys, and the lack of measures of potential mediating variables. Analyses of income relative to people in one's nation and between-nation slopes together suggest that income standards are now largely global, with little effect of national social comparison.

  16. Biogenic Methane and the Rise of Oxygen

    NASA Technical Reports Server (NTRS)

    Catling, David; McKay, Christopher

    2001-01-01

    Oxygenic photosynthesis does not make the rise of oxygen inevitable. What is required is that reductant and oxygen be separated and permanently segregated. The usual picture for Earth is that oxygenic photosynthesis split CO2 into carbon and oxygen, with the carbon buried in sediments and the oxygen mostly taken up by oxides of iron and sulfur. The relatively small atmospheric reservoir of O2 is regulated by the carbon burial rate, reaction with volcanic and metamorphic gases, and oxidation of reduced carbon released as old sediments weather. Absent from this picture is a distinction between the Archean and modern times: on average, carbon burial fluxes would have been matched by oxygen losses then as now. Separation of reductant from oxidant is only provisional. No net oxidation of the continents occurs, and so no change of diagenetic, metamorphic, or volcanic gases is expected. Nor would any change in oxidative weathering be expected. Something more than carbon burial is required to make the Archean different. The escape of hydrogen to space permanently separates the reductant from the oxidant. Hydrogen escape is widely believed to have led to the present highly oxidized states of Mars and Venus. Hydrogen escape has usually been thought small for Archaean Earth, because water vapor is cold-trapped at the troposphere and thus held to levels of a few ppmv in the stratosphere. This cold trapping renders hydrogen escape negligible. However, methane is not cold trapped, and its expected abundance in the Archaean, given low oxygen levels and a biogenic source, would have been high, probably more than 100 times present. At such levels methane would have driven geologically significant levels of hydrogen escape. Additional information is contained in the original extended abstract.

  17. Rising Sea Levels: Truth or Scare?

    ERIC Educational Resources Information Center

    Peacock, Alan

    2007-01-01

    When "ITV News" ran an item that shocked the author, about rising sea levels that will have caused the entire evacuation of the islands by the end of this year, he began to wonder whether the Pacific Ocean is really rising as fast as this. The media reporting of such things can be a double-edged sword. On the one hand, it brought to the author's…

  18. Subsidence and Relative Sea-level Rise in Threatened Deltas

    NASA Astrophysics Data System (ADS)

    Syvitski, J. P.; Higgins, S.

    2014-12-01

    In determining the risk lowland deltaic topography, as threatened by sea level rise and land subsidence, a number of important processes must be evaluated. Sea level rise is a global process but with local manifestations. Asian deltas have been experiencing higher rates of sea level rise due to the steric impact on dynamic (ocean) topography. Other large scale geophysical impacts on relative sea level at the local scale include the isostatic and flexural response to Holocene sea level history, Holocene sediment loads, and in former ice sheet zones --- glacial rebound. Tectonism does play a role on relative sea level rise, particularly in South America where the Eastern coastline, particularly Argentina, is rising relative to regional sea levels. Subsidence is impacted by both natural ground compaction, and accelerated compaction due to, for example, peat oxidation that often has a human driver (e.g. swamp reclammation). Subsidence is also impacted by the extraction of deeper deposits of petroleum and water. Rates of delta subsidence vary widely, depending on the magnitude of the anthropogenic driver, from a few mm/y to 100's of mm/y. Ground water withdrawal is the dominant reason behind much of the world's coastal subsidence, with important exceptions. On average subsidence rates (all causes) now contribute to local sea level innundations at rates four times faster then sea level is rising. New technologies, particularly InSAR and GPS methods, can often pin point the local cause (e.g. water withdrawl for agriculture versus for aquaculture). Subsurface soil or rock heterogeneity, and other very local geological patterns such as historical river pathways, also influence the temporal and spatial patterns associated with delta subsidence.

  19. The Rise of IPv6: Benefits and Costs of Transforming Military Cyberspace

    DTIC Science & Technology

    2015-04-01

    March–April 2015 Air & Space Power Journal | 103 Feature The Rise of IPv6 Benefits and Costs of Transforming Military Cyberspace Dr. Panayotis A...2015 4. TITLE AND SUBTITLE The Rise of IPv6: Benefits and Costs of Transforming Military Cyberspace 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...Journal | 104 Yannakogeorgos The Rise of IPv6 Feature loted and autonomous systems that will in time become core mission enablers.1 Too often

  20. Preparing Coastal Parks for Future Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Young, R.; Peek, K.

    2012-04-01

    The United States National Park Service (NPS) manages significant stretches of shoreline along the U.S. Atlantic, Pacific, and Gulf Coasts that are vulnerable to long-term sea level rise, shoreline erosion, and storm impacts. These parks have a wide variety of missions— protecting some of the nation's most important natural and cultural resources. The parks must also provide visitor access and education requiring infrastructure such as roads, visitor centers, trails, and buildings for facilities management. Planning for the likely impacts from sea level rise to both resources and infrastructure is a complex balancing act. Using coastal engineering to protect cultural resources or infrastructure may harm natural resources. At the same time, there are clearly some cultural and historical resources that are so critical that they must be protected. In an attempt to begin to attack this dilemma, the NPS Climate Change Response Program has initiated a sea level rise adaptation study that will provide a first-order tally of the park assets at risk to sea level rise and to begin to develop a plan for prioritizing those assets that must be protected, those that can be moved or abandoned, and an examination of how best to approach this without harming critical natural resources. This presentation will discuss the preliminary results of this effort along with several relevant case studies.

  1. Visualizing Sea Level Rise with Augmented Reality

    NASA Astrophysics Data System (ADS)

    Kintisch, E. S.

    2013-12-01

    Looking Glass is an application on the iPhone that visualizes in 3-D future scenarios of sea level rise, overlaid on live camera imagery in situ. Using a technology known as augmented reality, the app allows a layperson user to explore various scenarios of sea level rise using a visual interface. Then the user can see, in an immersive, dynamic way, how those scenarios would affect a real place. The first part of the experience activates users' cognitive, quantitative thinking process, teaching them how global sea level rise, tides and storm surge contribute to flooding; the second allows an emotional response to a striking visual depiction of possible future catastrophe. This project represents a partnership between a science journalist, MIT, and the Rhode Island School of Design, and the talk will touch on lessons this projects provides on structuring and executing such multidisciplinary efforts on future design projects.

  2. Sea Level Rise in Santa Clara County

    NASA Technical Reports Server (NTRS)

    Milesi, Cristina

    2005-01-01

    Presentation by Cristina Milesi, First Author, NASA Ames Research Center, Moffett Field, CA at the "Meeting the Challenge of Sea Level Rise in Santa Clara County" on June 19, 2005 Santa Clara County, bordering with the southern portion of the San Francisco Bay, is highly vulnerable to flooding and to sea level rise (SLR). In this presentation, the latest sea level rise projections for the San Francisco Bay will be discussed in the context of extreme water height frequency and extent of flooding vulnerability. I will also present preliminary estimations of levee requirements and possible mitigation through tidal restoration of existing salt ponds. The examples will draw mainly from the work done by the NASA Climate Adaptation Science Investigators at NASA Ames.

  3. Quality and the Rise of Value-Added in Education: The Case of Ireland

    ERIC Educational Resources Information Center

    Brown, Martin; McNamara, Gerry; O'Hara, Joe

    2016-01-01

    This paper examines the rise of value-added as a measure of quality in education. As a point of departure, the paper begins with an analysis of the rise of the concept of quality in education and discusses how, at times, various contradictory determinants of quality have managed to influence the evaluation and assessment frameworks of most…

  4. Who Gets a Mentor? A Longitudinal Assessment of the Rising Star Hypothesis

    ERIC Educational Resources Information Center

    Singh, Romila; Ragins, Belle Rose; Tharenou, Phyllis

    2009-01-01

    This study assessed the rising star hypothesis, which proposes that individuals who are on the fast track to career success are more likely to gain mentors than others. The study used a sample of employees who had never been mentored and examined the relationship between rising star attributes measured at Time 1 and the attainment of a mentor a…

  5. Large lateral photovoltaic effect with ultrafast relaxation time in SnSe/Si junction

    NASA Astrophysics Data System (ADS)

    Wang, Xianjie; Zhao, Xiaofeng; Hu, Chang; Zhang, Yang; Song, Bingqian; Zhang, Lingli; Liu, Weilong; Lv, Zhe; Zhang, Yu; Tang, Jinke; Sui, Yu; Song, Bo

    2016-07-01

    In this paper, we report a large lateral photovoltaic effect (LPE) with ultrafast relaxation time in SnSe/p-Si junctions. The LPE shows a linear dependence on the position of the laser spot, and the position sensitivity is as high as 250 mV mm-1. The optical response time and the relaxation time of the LPE are about 100 ns and 2 μs, respectively. The current-voltage curve on the surface of the SnSe film indicates the formation of an inversion layer at the SnSe/p-Si interface. Our results clearly suggest that most of the excited-electrons diffuse laterally in the inversion layer at the SnSe/p-Si interface, which results in a large LPE with ultrafast relaxation time. The high positional sensitivity and ultrafast relaxation time of the LPE make the SnSe/p-Si junction a promising candidate for a wide range of optoelectronic applications.

  6. Project RISE: Workplace Literacy Education in Context.

    ERIC Educational Resources Information Center

    Beder, Hal; And Others

    A reflective self-assessment process was used to evaluate Project RISE, a 1-year, federally funded workplace literacy project. The goal of the evaluation was to help staff understand their collective experience in a way that might help them to serve their clients more effectively in the future. A list of the most critical problems faced by staff…

  7. Rising to the Challenge: 2009 Annual Report

    ERIC Educational Resources Information Center

    Southern Regional Education Board (SREB), 2009

    2009-01-01

    This annual report highlights SREB's recent achievements and how its services are helping the 16 member states rise to the challenge of improving education at all levels. The report also includes remarks from the Board Chair and President, acknowledges chief contributors and lists members of the Board, Legislative Advisory Council and SREB staff.…

  8. Rising Tides: Faculty Expectations of Library Websites

    ERIC Educational Resources Information Center

    Nicol, Erica Carlson; O'English, Mark

    2012-01-01

    Looking at 2003-2009 LibQUAL+ responses at research-oriented universities in the United States, faculty library users report a significant and consistent rise in desires and expectations for library-provided online tools and websites, even as student user groups show declining or leveling expectations. While faculty, like students, also report…

  9. The Rise of the Digital Public Library

    ERIC Educational Resources Information Center

    McKendrick, Joseph

    2012-01-01

    There is a growing shift to digital offerings among public libraries. Libraries increasingly are fulfilling roles as technology hubs for their communities, with high demand for technology and career development training resources. Ebooks and other digital materials are on the rise, while print is being scaled back. More libraries are turning to…

  10. Agriculture waste and rising CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, there are many uncertainties concerning agriculture’s role in global environmental change including the effects of rising atmospheric CO2 concentration. A viable and stable world food supply depends on productive agricultural systems, but environmental concerns within agriculture have to...

  11. Sea level rise and coastal erosion

    NASA Astrophysics Data System (ADS)

    Leatherman, S. P.; Zhang, K.; Douglas, B. C.

    2003-04-01

    One of the most certain consequences of global warming is an increase of global (eustatic) sea level. The resulting inundation from rising seas will heavily impact low-lying areas; at least 100 million persons live within one meter of mean sea level and are at increased risk in the coming decades. The very existence of some island states and deltaic coasts is threatened by sea level rise. An additional threat affecting some of the most heavily developed and economically valuable real estate will come from an exacerbation of sandy beach erosion. As the beach is lost, fixed structures nearby are increasingly exposed to the direct impact of storm waves, and will ultimately be damaged or destroyed unless expensive protective measures are taken. It has long been speculated that the underlying rate of long-term sandy beach erosion is two orders of magnitude greater than the rate of rise of sea level, so that any significant increase of sea level has dire consequences for coastal inhabitants. We present an analysis of a large and consistent database of shoreline positions and sea levels to show that there is an underlying highly multiplicative relation of sandy beach erosion to sea level rise. This result means that the already-severe coastal erosion problems witnessed in the 20th century will be exacerbated in the 21st century under plausible global warming scenarios.

  12. How To Attack Rising Energy Costs.

    ERIC Educational Resources Information Center

    Fickes, Michael

    2001-01-01

    Presents manufacturer and engineer suggestions on how schools can solve their rising energy costs in the face of more demanding classroom needs placing greater demands of Heating and air conditioning ventilation systems. The use of CO2 sensors, boiler technology and two-pipe systems are explored. (GR)

  13. Relative Deprivation, Rising Expectations, and Black Militancy

    ERIC Educational Resources Information Center

    Abeles, Ronald P.

    1976-01-01

    Investigates the role of relative deprivation (RD) and rising expectations (RE) as mediating variables between social structure and black militancy through secondary analyses of survey data of blacks living in Cleveland and Miami in the late 1960s. Alternative explanations and implications derived from the present data and the theories for the…

  14. Sea Level Rise National Coastal Property Model

    EPA Science Inventory

    The impact of sea level rise on coastal properties depends critically on the human response to the threat, which in turn depends on several factors, including the immediacy of the risk, the magnitude of property value at risk, options for adapting to the threat and the cost of th...

  15. Onshore rig surplus diminishes as demand rises

    SciTech Connect

    Isenberg, E.M.

    1997-09-22

    US and international onshore surplus rig supply is diminishing rapidly as rig demand in many regions continues to increase. Consequently, capital costs associated with reactivating, constructing, and refurbishing new and existing rigs are on the rise. In addition, rising operating costs are putting upward pressure on operating costs. In order to justify replacement of existing rigs, US rig day rates will need to more than double. Current rig-market indicators show that rig demand should continue to rise at current levels, or even accelerate. Day rates will have to rise to a level that justifies investments in new capacity, and with continuing rig attrition, even more rigs will have to be built to offset deletions. It is not a matter of whether this will occur, but only when. This will not necessarily threaten the operators` returns over the long-term because technological advances will continue, resulting in lower exploration and production costs. The paper discusses the drivers of increasing demand, faster recovery rates, increasing rig demand, diminishing rig supply, and escalating component costs.

  16. Tuition Rising: Why College Costs So Much.

    ERIC Educational Resources Information Center

    Ehrenberg, Ronald G.

    This book explores the causes of tuition inflation, using Cornell University (New York) as a prototypical institution. There are 9 sections with 20 chapters. Section 1, "Setting the Stage," includes (1) "Why Do Costs Keep Rising at Selective Private Colleges and Universities?" and (2) "Who Is In Charge of the…

  17. Updating Maryland's sea-level rise projections

    USGS Publications Warehouse

    Boesch, Donald F.; Atkinson, Larry P.; Boicourt, William C.; Boon, John D.; Cahoon, Donald R.; Dalrymple, Robert A.; Ezer, Tal; Horton, Benjamin P.; Johnson, Zoe P.; Kopp, Robert E.; Li, Ming; Moss, Richard H.; Parris, Adam; Sommerfield, Christopher K.

    2013-01-01

    With its 3,100 miles of tidal shoreline and low-lying rural and urban lands, “The Free State” is one of the most vulnerable to sea-level rise. Historically, Marylanders have long had to contend with rising water levels along its Chesapeake Bay and Atlantic Ocean and coastal bay shores. Shorelines eroded and low-relief lands and islands, some previously inhabited, were inundated. Prior to the 20th century, this was largely due to the slow sinking of the land since Earth’s crust is still adjusting to the melting of large masses of ice following the last glacial period. Over the 20th century, however, the rate of rise of the average level of tidal waters with respect to land, or relative sea-level rise, has increased, at least partially as a result of global warming. Moreover, the scientific evidence is compelling that Earth’s climate will continue to warm and its oceans will rise even more rapidly. Recognizing the scientific consensus around global climate change, the contribution of human activities to it, and the vulnerability of Maryland’s people, property, public investments, and natural resources, Governor Martin O’Malley established the Maryland Commission on Climate Change on April 20, 2007. The Commission produced a Plan of Action that included a comprehensive climate change impact assessment, a greenhouse gas reduction strategy, and strategies for reducing Maryland’s vulnerability to climate change. The Plan has led to landmark legislation to reduce the state’s greenhouse gas emissions and a variety of state policies designed to reduce energy consumption and promote adaptation to climate change.

  18. Sea Level Rise Impacts On Infrastructure Vulnerability

    NASA Astrophysics Data System (ADS)

    Pasqualini, D.; Mccown, A. W.; Backhaus, S.; Urban, N. M.

    2015-12-01

    Increase of global sea level is one of the potential consequences of climate change and represents a threat for the U.S.A coastal regions, which are highly populated and home of critical infrastructures. The potential danger caused by sea level rise may escalate if sea level rise is coupled with an increase in frequency and intensity of storms that may strike these regions. These coupled threats present a clear risk to population and critical infrastructure and are concerns for Federal, State, and particularly local response and recovery planners. Understanding the effect of sea level rise on the risk to critical infrastructure is crucial for long planning and for mitigating potential damages. In this work we quantify how infrastructure vulnerability to a range of storms changes due to an increase of sea level. Our study focuses on the Norfolk area of the U.S.A. We assess the direct damage of drinking water and wastewater facilities and the power sector caused by a distribution of synthetic hurricanes. In addition, our analysis estimates indirect consequences of these damages on population and economic activities accounting also for interdependencies across infrastructures. While projections unanimously indicate an increase in the rate of sea level rise, the scientific community does not agree on the size of this rate. Our risk assessment accounts for this uncertainty simulating a distribution of sea level rise for a specific climate scenario. Using our impact assessment results and assuming an increase of future hurricanes frequencies and intensities, we also estimate the expected benefits for critical infrastructure.

  19. Is the detection of accelerated sea level rise imminent?

    PubMed Central

    Fasullo, J. T.; Nerem, R. S.; Hamlington, B.

    2016-01-01

    Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption. A consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade. PMID:27506974

  20. Is the detection of accelerated sea level rise imminent?

    PubMed

    Fasullo, J T; Nerem, R S; Hamlington, B

    2016-08-10

    Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption. A consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.

  1. Physics Impact of Improvements to the Beam Timing Resolution at MicroBooNE

    NASA Astrophysics Data System (ADS)

    Miceli, Tia; MicroBooNE Collaboration

    2017-01-01

    The MicroBooNE detector is a liquid argon time-projection chamber (89 tons active mass) at Fermilab designed to measure interactions of neutrinos from the Booster Neutrino Beamline (BNB) and the Neutrinos at the Main Injector (NuMI) beamline. During the first year of data-taking, the arrival time of the neutrinos was only understood with an accuracy of 100 ns for the BNB, and was unverified for NuMI. A set of upgrades has been implemented that will reduce the uncertainty in beam delivery time by two orders of magnitude, significantly improving our ability to observe neutral-current elastic interactions in the BNB, and kaon decays at rest using NuMI. This talk explains the improvements in neutrino arrival timing, their impact on these two analyses, and the overall benefit to all other MicroBooNE measurements. DOE Office of Science.

  2. Estimating Hardness from the USDC Tool-Bit Temperature Rise

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart

    2008-01-01

    A method of real-time quantification of the hardness of a rock or similar material involves measurement of the temperature, as a function of time, of the tool bit of an ultrasonic/sonic drill corer (USDC) that is being used to drill into the material. The method is based on the idea that, other things being about equal, the rate of rise of temperature and the maximum temperature reached during drilling increase with the hardness of the drilled material. In this method, the temperature is measured by means of a thermocouple embedded in the USDC tool bit near the drilling tip. The hardness of the drilled material can then be determined through correlation of the temperature-rise-versus-time data with time-dependent temperature rises determined in finite-element simulations of, and/or experiments on, drilling at various known rates of advance or known power levels through materials of known hardness. The figure presents an example of empirical temperature-versus-time data for a particular 3.6-mm USDC bit, driven at an average power somewhat below 40 W, drilling through materials of various hardness levels. The temperature readings from within a USDC tool bit can also be used for purposes other than estimating the hardness of the drilled material. For example, they can be especially useful as feedback to control the driving power to prevent thermal damage to the drilled material, the drill bit, or both. In the case of drilling through ice, the temperature readings could be used as a guide to maintaining sufficient drive power to prevent jamming of the drill by preventing refreezing of melted ice in contact with the drill.

  3. DETECTING MASSIVE GRAVITONS USING PULSAR TIMING ARRAYS

    SciTech Connect

    Lee, Kejia; Kramer, Michael; Jenet, Fredrick A.; Price, Richard H.; Wex, Norbert

    2010-10-20

    At the limit of weak static fields, general relativity becomes Newtonian gravity with a potential field that falls off as inverse distance rather than a theory of Yukawa-type fields with a finite range. General relativity also predicts that the speed of disturbances of its waves is c, the vacuum light speed, and is non-dispersive. For these reasons, the graviton, the boson for general relativity, can be considered to be massless. Massive gravitons, however, are features of some alternatives to general relativity. This has motivated experiments and observations that, so far, have been consistent with the zero-mass graviton of general relativity, but further tests will be valuable. A basis for new tests may be the high sensitivity gravitational wave (GW) experiments that are now being performed and the higher sensitivity experiments that are being planned. In these experiments, it should be feasible to detect low levels of dispersion due to non-zero graviton mass. One of the most promising techniques for such a detection may be the pulsar timing program that is sensitive to nano-Hertz GWs. Here, we present some details of such a detection scheme. The pulsar timing response to a GW background with the massive graviton is calculated, and the algorithm to detect the massive graviton is presented. We conclude that, with 90% probability, massless gravitons can be distinguished from gravitons heavier than 3 x 10{sup -22} eV (Compton wavelength {lambda}{sub g} = 4.1 x 10{sup 12} km), if bi-weekly observation of 60 pulsars is performed for 5 years with a pulsar rms timing accuracy of 100 ns. If 60 pulsars are observed for 10 years with the same accuracy, the detectable graviton mass is reduced to 5 x 10{sup -23} eV ({lambda}{sub g} = 2.5 x 10{sup 13} km); for 5 year observations of 100 or 300 pulsars, the sensitivity is respectively 2.5 x 10{sup -22} ({lambda}{sub g} = 5.0 x 10{sup 12} km) and 10{sup -22} eV ({lambda}{sub g} = 1.2 x 10{sup 13} km). Finally, a 10 year

  4. The sitting and rising test for assessing people with chronic stroke

    PubMed Central

    Ng, Shamay S.M.; Fong, Shirley S.M.; Chan, Wayne L.S.; Hung, Ben K.Y.; Chung, Ricci K.S.; Chim, Tina H.T.; Kwong, Patrick W.H.; Liu, Tai-Wa; Tse, Mimi M.Y.; Chung, Raymond C.K.

    2016-01-01

    [Purpose] To investigate the inter-rater and test-retest reliability of the sitting-rising test (SRT), the correlations of sitting-rising test scores with measures of strength, balance, community integration and quality of life, as well as the cut-off score which best discriminates people with chronic stroke from healthy older adults were investigated. [Subjects and Methods] Subjects with chronic stroke (n=30) and healthy older adults (n=30) were recruited. The study had a cross-sectional design, and was carried out in a university rehabilitation laboratory. Sitting-rising test performance was scored on two occasions. Other measurements included ankle dorsiflexor and plantarflexor strength, the Fugl-Meyer assessment, the Berg Balance Scale, the timed up and go test, the five times sit-to-stand test, the limits of stability test, and measures of quality of health and community integration. [Results] Sitting-rising test scores demonstrated good to excellent inter-rater and test-retest reliabilities (ICC=0.679 to 0.967). Sitting-rising test scores correlated significantly with ankle strength, but not with other test results. The sitting-rising test showed good sensitivity and specificity. A cut-off score of 7.8 best distinguished healthy older adults from stroke subjects. [Conclusions] The sitting-rising test is a reliable and sensitive test for assessing the quality of sitting and rising movements. Further studies with a larger sample are required to investigate the test’s validity. PMID:27390398

  5. Coastal subsidence and relative sea level rise

    USGS Publications Warehouse

    Ingebritsen, Steven E.; Galloway, Devin L.

    2014-01-01

    Subsurface fluid-pressure declines caused by pumping of groundwater or hydrocarbons can lead to aquifer-system compaction and consequent land subsidence. This subsidence can be rapid, as much as 30 cm per year in some instances, and large, totaling more than 13 m in extreme examples. Thus anthropogenic subsidence may be the dominant contributor to relative sea-level rise in coastal environments where subsurface fluids are heavily exploited. Maximum observed rates of human-induced subsidence greatly exceed the rates of natural subsidence of unconsolidated sediments (~0.1–1 cm yr−1) and the estimated rates of ongoing global sea-level rise (~0.3 cm yr−1).

  6. Hurricanes, sea level rise, and coastal change

    USGS Publications Warehouse

    Sallenger,, Asbury H.; Wang, Ping; Rosati, Julie D.; Roberts, Tiffany M.

    2011-01-01

    Sixteen hurricanes have made landfall along the U.S. east and Gulf coasts over the past decade. For most of these storms, the USGS with our partners in NASA and the U.S. Army Corps of Engineers have flown before and after lidar missions to detect changes in beaches and dunes. The most dramatic changes occurred when the coasts were completely submerged in an inundation regime. Where this occurred locally, a new breach was cut, like during Hurricane Isabel in North Carolina. Where surge inundated an entire island, the sand was stripped off leaving marshy outcrops behind, like during Hurricane Katrina in Louisiana. Sea level rise together with sand starvation and repeated hurricane impacts could increase the probabilities of inundation and degrade coasts more than sea level rise alone.

  7. Igneous rocks of the East Pacific Rise

    USGS Publications Warehouse

    Engel, A.E.J.; Engel, C.G.

    1964-01-01

    The apical parts of large volcanoes along the East Pacific Rise (islands and seamounts) are encrusted with rocks of the alkali volcanic suite (alkali basalt, andesine- and oligoclase-andesite, and trachyte). In contrast, the more submerged parts of the Rise are largely composed of a tholeiitic basalt which has low concentrations of K, P, U, Th, Pb, and Ti. This tholeiitic basalt is either the predominant or the only magma generated in the earth's mantle under oceanic ridges and rises. It is at least 1000-fold more abundant than the alkali suite, which is probably derived from tholeiitic basalt by magmatic differentiation in and immediately below the larger volcanoes. Distinction of oceanic tholeiites from almost all continental tholeiites is possible on the simple basis of total potassium content, with the discontinuity at 0.3 to 0.5 percent K2O by weight. Oceanic tholeiites also are readily distinguished from some 19 out of 20 basalts of oceanic islands and seamount cappings by having less than 0.3 percent K2O by weight and more than 48 percent SiO2. Deep drilling into oceanic volcanoes should, however, core basalts transitional between the oceanic tholeiites and the presumed derivative alkali basalts.The composition of the oceanic tholeiites suggests that the mantle under the East Pacific Rise contains less than 0.10 percent potassium oxide by weight; 0.1 part per million of uranium and 0.4 part of thorium; a potassium:rubidium ratio of about 1200 and a potassium: uranium ratio of about 104.

  8. Claritas rise, Mars: Pre-Tharsis magmatism?

    USGS Publications Warehouse

    Dohm, J.M.; Anderson, R.C.; Williams, J.-P.; Ruiz, J.; McGuire, P.C.; Buczkowski, D.L.; Wang, R.; Scharenbroich, L.; Hare, T.M.; Connerney, J.E.P.; Baker, V.R.; Wheelock, S.J.; Ferris, J.C.; Miyamoto, H.

    2009-01-01

    Claritas rise is a prominent ancient (Noachian) center of tectonism identified through investigation of comprehensive paleotectonic information of the western hemisphere of Mars. This center is interpreted to be the result of magmatic-driven activity, including uplift and associated tectonism, as well as possible hydrothermal activity. Coupled with its ancient stratigraphy, high density of impact craters, and complex structure, a possible magnetic signature may indicate that it formed during an ancient period of Mars' evolution, such as when the dynamo was in operation. As Tharsis lacks magnetic signatures, Claritas rise may pre-date the development of Tharsis or mark incipient development, since some of the crustal materials underlying Tharsis and older parts of the magmatic complex, respectively, could have been highly resurfaced, destroying any remanent magnetism. Here, we detail the significant characteristics of the Claritas rise, and present a case for why it should be targeted by the Mars Odyssey, Mars Reconnaissance Orbiter, and Mars Express spacecrafts, as well as be considered as a prime target for future tier-scalable robotic reconnaissance. ?? 2009 Elsevier B.V.

  9. Glacier Contributions to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Gardner, A. S.; Cogley, J. G.; Moholdt, G.; Wouters, B.; Wiese, D. N.

    2015-12-01

    Global mean sea level is rising in response to two primary factors: warming oceans and diminishing glaciers and ice sheets. If melted completely, glaciers would raise sea levels by half a meter, much less than that the 80 meters or so that would result from total melt of the massive Greenland and Antarctic ice sheets. That is why glacier contributions to sea level rise have been less studied, allowing estimates of to vary widely. Glacier contributions to sea level change are challenging to quantify as they are broadly distributed, located in remote and poorly accessible high latitude and high altitude regions, and ground observations are sparse. Advances in satellite altimetry (ICESat) and gravimetry (GRACE) have helped, but they also have their own challenges and limitations. Here we present an updated (2003-2014) synthesis of multiple techniques adapted for varying regions to show that rates of glacier loss change little between the 2003-2009 and 2003-2014 periods, accounting for roughly one third of global mean sea level rise. Over the next century and beyond glaciers are expected to continue to contribute substantial volumes of water to the world's oceans, motivating continued study of how glaciers respond to climate change that will improve projections of future sea levels.

  10. The Darwin Rise: A Cretaceous superswell?

    NASA Astrophysics Data System (ADS)

    McNutt, M. K.; Winterer, E. L.; Sager, W. W.; Natland, J. H.; Ito, G.

    1990-07-01

    The Japanese Guyots, Wake Guyots, and Mid-Pacific Mountains are part of a broad area of Cretaceous volcanism in the western Pacific termed the “Darwin Rise.” Based on Seabeam bathymetric data we classify these drowned volcanic islands as: type “A,” those that advanced to the atoll stage before final submergence; type “B,” those that drowned at the barrier reef stage; and type “V,” those with little or no reef material on their volcanic summits. Widespread evidence for karst topography extending to depths of 200 m on the summits of A and B guyots sheds new light on events leading to the synchronous extinction of reefs on the Darwin Rise in the mid-Cretaceous. We propose that after the formation of the reefs on the A and B guyots, the entire region was elevated at approximately the Aptian-Albian boundary (113 Ma) to form a superswell similar to that existing now in French Polynesia. The type V guyots formed on this anomalously shallow lithosphere. The demise of the reefs was the direct result of the rise of this superswell, although climate factors may have prevented reef recolonization following its later subsidence.

  11. Temperature rise in tissue ablation using multi-frequency ultrasound.

    PubMed

    Sijia Guo; Yun Jing; Xiaoning Jiang

    2013-08-01

    High-intensity focused ultrasound (HIFU) is becoming an increasingly important noninvasive surgical tool, despite the challenges in temperature rise control and unwanted heating problems. In this study, experiments and simulations on tissue ablation effectiveness were performed using multi-frequency HIFU with frequency differences of more than 500 kHz (center frequencies are 950 kHz, 1.5 MHz, and 3.3 MHz). In the experiments, the temperature was recorded as chicken breast tissue was heated by single-frequency, dual-frequency, and tri-frequency HIFU configurations at controlled acoustic power and exposure time. 5% to 10% temperature rise differences were observed between single- and multi-frequency modes, indicating that multi-frequency HIFU is more effective at producing faster temperature rises. Cavitation detection tests were conducted to compare the cavitation pressure fields between single- and multi-frequency ultrasound. Moreover, simulations on single-frequency and multi-frequency acoustic fields as well as bio-heating-induced temperature fields were performed. With the comparison between experimental and simulation results, we believe that the more effective tissue ablation using multi-frequency ultrasound is likely attributed to the enhanced cavitation, a promising result for HIFU applications.

  12. 21 CFR 137.180 - Self-rising flour.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Self-rising flour. 137.180 Section 137.180 Food... Flours and Related Products § 137.180 Self-rising flour. (a) Self-rising flour, self-rising white flour, self-rising wheat flour, is an intimate mixture of flour, sodium bicarbonate, and one or more of...

  13. 21 CFR 137.180 - Self-rising flour.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Self-rising flour. 137.180 Section 137.180 Food... Flours and Related Products § 137.180 Self-rising flour. (a) Self-rising flour, self-rising white flour, self-rising wheat flour, is an intimate mixture of flour, sodium bicarbonate, and one or more of...

  14. 21 CFR 137.180 - Self-rising flour.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Self-rising flour. 137.180 Section 137.180 Food... Flours and Related Products § 137.180 Self-rising flour. (a) Self-rising flour, self-rising white flour, self-rising wheat flour, is an intimate mixture of flour, sodium bicarbonate, and one or more of...

  15. 21 CFR 137.180 - Self-rising flour.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Self-rising flour. 137.180 Section 137.180 Food... Flours and Related Products § 137.180 Self-rising flour. (a) Self-rising flour, self-rising white flour, self-rising wheat flour, is an intimate mixture of flour, sodium bicarbonate, and one or more of...

  16. PERSPECTIVE: The tripping points of sea level rise

    NASA Astrophysics Data System (ADS)

    Hecht, Alan D.

    2009-12-01

    coastal management in which options for shore protection or retreats are clearly identified and where economic, ecosystem and social impacts can be clearly evaluated. At stake are both the future of wetlands that provide important ecosystem services and the safety and sustainability of our coastal communities. This is a huge challenge requiring adequate data, long-term planning, federal-state cooperation, and integration of environmental laws. The time is at hand to assess a business-as-usual response to sea level rise or to explore a more holistic and integrated approach. President Obama has said: `The threat from climate change is serious, it is urgent, and it is growing. Our generation's response to this challenge will be judged by history, for if we fail to meet it—boldly, swiftly, and together—we risk consigning future generations to an irreversible catastrophe' [3]. Though the President was talking about action to reduce emissions of greenhouse gases, cooperation to address the consequences of rising sea level and changing climate is just as urgent. References [1] Titus J G et al 2009 State and local governments plan for development of most land vulnerable to rising sea level along the US Atlantic coast Environ. Res. Lett. 4 044008 [2] US Global Change Research Program 2009 Global Climate Change Impacts in the United States (June 2009) [3] www.whitehouse.gov/the_press_office/Remarks-by-the-President-at-UN-Secretary-General-Ban-Ki-moons-Climate-Change-Summit/

  17. Capillary rise in crumped-sheets of paper

    NASA Astrophysics Data System (ADS)

    Torres Victoria, Ayax Hernando; Salgado, Moisés; Peralta, Salomón; Wong, Franciso; Medina, Abraham

    2016-11-01

    In this work we report experiments on the capillary rise of water into crumpled paper, in order to understand how the controlled damage of a soft material, like paper (hand-crumpled paper sheets), improves their capabilities of liquid sorption. We have done a series of experiments where a different number of crumples (from zero up to fifty) were made on different rectangular paper pieces and we found that an increasing number of crumples enhances such a capability. Characteristic power laws for the front of elevation, h, versus the elapsed time to reach such height, t, are reported.

  18. Leveraging EU Soft Power to Shape the Rise of China

    DTIC Science & Technology

    2013-03-01

    to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1 . REPORT DATE (DD-MM-YYYY) xx-03-2013 2. REPORT...engage European soft power in order to assist in shaping China’s accent as an up and coming world power. The intent is not to retard China’s rise

  19. Consumerism and wellness: rising tide, falling cost.

    PubMed

    Domaszewicz, Alexander

    2008-01-01

    Annual employer-sponsored health plan cost increases have been slowing incrementally due to slowing health care utilization--a phenomenon very likely tied to the proliferation of health management activities, wellness programs and other consumerism strategies. This article describes the sharp rise in recent years of consumer-directed health plans (CDHPs) and explains what developments must happen for genuine consumer-directed health care to realize its full potential. These developments include gathering transparent health care information, increasing consumer demand for that information and creating truly intuitive data solutions that allow consumers to easily access information in order to make better health care decisions.

  20. Liquid jet pumped by rising gas bubbles

    NASA Technical Reports Server (NTRS)

    Hussain, N. A.; Siegel, R.

    1975-01-01

    A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature.

  1. Gas-rise velocities during kicks

    SciTech Connect

    White, D.B. )

    1991-12-01

    This paper reports on experiments to examine gas migration rates in drilling muds that were performed in a 15-m-long, 200-mm-ID inclinable flow loop where air injection simulates gas entry during a kick. These tests were conducted using a xanthum gum (a common polymer used in drilling fluids) solution to simulate drilling muds as the liquid phase and air as the gas phase. This work represents a significant extension of existing correlations for gas/liquid flows in large pipe diameters with non- Newtonian fluids. Bubbles rise faster in drilling muds than in water despite the increased viscosity. This surprising result is caused by the change in the flow regime, with large slug-type bubbles forming at lower void fractions. The gas velocity is independent of void fraction, thus simplifying flow modeling. Results show that a gas influx will rise faster in a well than previously believed. This has major implications for kick simulation, with gas arriving at the surface earlier than would be expected and the gas outflow rate being higher than would have been predicted. A model of the two-phase gas flow in drilling mud, including the results of this work, has been incorporated into the joint Schlumberger Cambridge Research (SCR)/BP Intl. kick model.

  2. Initiation of the Slow-Rise and Fast-Rise Phases of an Erupting Solar Filament by Localized Emerging Magnetic Field via Microflaring

    NASA Technical Reports Server (NTRS)

    Sterling, A. C.; Moore, R. L.; Harra, L. K.

    2006-01-01

    EUV data from EIT show that a filament of 2001 February 28 underwent a slow-rise phase lasting about 6 hrs, before rapidly erupting in a fast-rise phase. Concurrent images in soft X-rays (SXRs) from Yohkoh/SXT show that a series of three microflares, prominent in SXT images but weak in EIT approx.195 Ang EUV images, occurred near one end of the filament. The first and last microflares occurred respectively in conjunction with the start of the slow-rise phase and the start of the fast-rise phase, and the second microflare corresponded to a kink in the filament trajectory. Beginning within 10 hours of the start of the slow rise, new magnetic flux emerged at the location of the microflaring. This localized new flux emergence and the resulting microflares, consistent with reconnection between the emerging field and the sheared sigmoid core magnetic field holding the filament, apparently caused the slow rise of this field and the transition to explosive eruption. For the first time in such detail, the observations show this direct action of localized emerging flux in the progressive destabilization of a sheared core field in the onset of a coronal mass ejection (CME). Similar processes may have occurred in other recently-studied events, NASA supported this work through NASA SR&T and SEC GI grants.

  3. Coastal sea level rise with warming above 2 °C.

    PubMed

    Jevrejeva, Svetlana; Jackson, Luke P; Riva, Riccardo E M; Grinsted, Aslak; Moore, John C

    2016-11-22

    Two degrees of global warming above the preindustrial level is widely suggested as an appropriate threshold beyond which climate change risks become unacceptably high. This "2 °C" threshold is likely to be reached between 2040 and 2050 for both Representative Concentration Pathway (RCP) 8.5 and 4.5. Resulting sea level rises will not be globally uniform, due to ocean dynamical processes and changes in gravity associated with water mass redistribution. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 °C goal. By 2040, with a 2 °C warming under the RCP8.5 scenario, more than 90% of coastal areas will experience sea level rise exceeding the global estimate of 0.2 m, with up to 0.4 m expected along the Atlantic coast of North America and Norway. With a 5 °C rise by 2100, sea level will rise rapidly, reaching 0.9 m (median), and 80% of the coastline will exceed the global sea level rise at the 95th percentile upper limit of 1.8 m. Under RCP8.5, by 2100, New York may expect rises of 1.09 m, Guangzhou may expect rises of 0.91 m, and Lagos may expect rises of 0.90 m, with the 95th percentile upper limit of 2.24 m, 1.93 m, and 1.92 m, respectively. The coastal communities of rapidly expanding cities in the developing world, and vulnerable tropical coastal ecosystems, will have a very limited time after midcentury to adapt to sea level rises unprecedented since the dawn of the Bronze Age.

  4. AN ESTIMATE OF THE DETECTABILITY OF RISING FLUX TUBES

    SciTech Connect

    Birch, A. C.; Braun, D. C.; Fan, Y.

    2010-11-10

    The physics of the formation of magnetic active regions (ARs) is one of the most important problems in solar physics. One main class of theories suggests that ARs are the result of magnetic flux that rises from the tachocline. Time-distance helioseismology, which is based on measurements of wave propagation, promises to allow the study of the subsurface behavior of this magnetic flux. Here, we use a model for a buoyant magnetic flux concentration together with the ray approximation to show that the dominant effect on the wave propagation is expected to be from the roughly 100 m s{sup -1} retrograde flow associated with the rising flux. Using a B-spline-based method for carrying out inversions of wave travel times for flows in spherical geometry, we show that at 3 days before emergence the detection of this retrograde flow at a depth of 30 Mm should be possible with a signal-to-noise level of about 8 with a sample of 150 emerging ARs.

  5. Cloud rise model for radiological dispersal devices events

    NASA Astrophysics Data System (ADS)

    Sharon, Avi; Halevy, Itzhak; Sattinger, Daniel; Yaar, Ilan

    2012-07-01

    As a part of the preparedness and response to possible radiological terror events, it is important to model the evolution of the radioactive cloud immediately after its formation, as a function of time, explosive quantity and local meteorological conditions. One of the major outputs of a cloud rise models is the evaluation of cloud top height, which is an essential input for most of the succeeding atmospheric dispersion models. This parameter strongly affects the radiological consequences of the event. Most of the cloud rise models used today, have been developed according to experiments were large quantities of explosives were used, within the range of hundreds of kilograms of TNT. The majority of these models, however, fail to address Radiological Dispersion Devices (RDD) events, which are typically characterized by smaller amounts of TNT. In this paper, a new, semi-empirical model that describes the vertical evolution of the cloud up to its effective height as a function of time, explosive quantity, atmospheric stability and horizontal wind speed, is presented. The database for this model is taken from five sets of experiments done in Israel during 2006-2009 under the "Green Field" (GF) project, using 0.25-100 kg of TNT.

  6. Time and space resolved measurement of the electron temperature, mass density and ionization state in the ablation plasma between two exploding Al wires

    SciTech Connect

    Knapp, P. F.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Hansen, S. B.

    2012-05-15

    We have determined the properties of plasma around and between two exploding wires using high-resolution x-ray absorption spectroscopy. Plasma densities and temperatures ranging from Greater-Than-Or-Equivalent-To 0.1g/cm{sup 3} and a few eV to less than 0.01 g/cm{sup 3} and 30 eV have been measured in experiments at Cornell University with two 40 {mu}m aluminum (Al) wires spaced 1 mm apart driven by {approx}150 kA peak current pulses with 100 ns rise time. The wire plasma was backlit by the 1.4-1.6 keV continuum radiation produced by a Mo wire X-pinch. The spectrometer employed two spherically bent quartz crystals to record the absorption and backlighter spectra simultaneously. The transition between the dense Al wire core and the coronal plasma is seen as a transition from cold K-edge absorption to Mg-, Na-, and finally Ne-like absorption at the boundary. In the plasma that accumulates between the wires, ionization states up to C-Like Al are observed. The spectrometer geometry and {approx}2{mu}m X-pinch source size provide 0.3 eV spectral resolution and 20 {mu}m spatial resolution enabling us to see 1s{yields} 2p satellite transitions as separate lines as well as O-, F-, and Ne-like 1s{yields} 3p transitions that have not been seen before. A step wedge was used to calibrate the transmission, enabling density to be measured within a factor of two and temperature to be measured within {+-}25%. A genetic algorithm was developed to fit synthetic spectra calculated using the collisional-radiative code SCRAM to the experimental spectra. In order to obtain agreement it was necessary to assume multiple plasma regions with variable thicknesses, thereby allowing the inferred plasma conditions to vary along the absorption path.

  7. Time-resolved electron temperature and electron density measurements in a nanosecond pulse filament discharge in H2-He and O2-He mixtures

    NASA Astrophysics Data System (ADS)

    Roettgen, A.; Shkurenkov, I.; Simeni Simeni, M.; Adamovich, I. V.; Lempert, W. R.

    2016-10-01

    Time evolution of electron density and electron temperature in a nanosecond pulse, diffuse filament electric discharge in H2-He and O2-He mixtures at a pressure of 100 Torr is studied by Thomson/pure rotational Raman scattering and kinetic modeling. The discharge is sustained between two spherical electrodes separated by a 1 cm gap and powered by high voltage pulses ~150 ns duration. Discharge energy coupled to the plasma filament 2-3 mm in diameter is 4-5 mJ/pulse, with specific energy loading of up to ~0.3 eV/molecule. At all experimental conditions, a rapid initial rise of electron temperature and electron density during the discharge pulse is observed, followed by the decay in the afterglow, over ~100 ns-1 µs. Electron density in the afterglow decays more rapidly as H2 or O2 fraction in the mixture is increased. In He/H2 mixtures, this is likely due to more rapid recombination of electrons in collisions with \\text{H}2+ and \\text{H}3+ ions, compared to recombination with \\text{He}2+ ions. In O2/He mixtures, electron density decay in the afterglow is affected by recombination with \\text{O}2+ and \\text{O}4+ ions, while the effect of three-body attachment is relatively minor. Peak electron number densities and electron temperatures are n e  =  (1.7-3.1) · 1014 cm-3 and T e  =  2.9-5.5 eV, depending on gas mixture composition. Electron temperature in the afterglow decays to approximately T e  ≈  0.3 eV, considerably higher compared to the gas temperature of T  =  300-380 K, inferred from O2 pure rotational Raman scattering spectra, due to superelastic collisions. The experimental results in helium and O2-He mixtures are compared with kinetic modeling predictions, showing good agreement.

  8. Liquid jet pumped by rising gas bubbles

    NASA Technical Reports Server (NTRS)

    Hussain, N. A.; Siegel, R.

    1975-01-01

    From observations of a stream of gas bubbles rising through a liquid, a two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. The bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they arise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature.

  9. The rise of the rhizosolenid diatoms.

    PubMed

    Damsté, Jaap S Sinninghe; Muyzer, Gerard; Abbas, Ben; Rampen, Sebastiaan W; Massé, Guillaume; Allard, W Guy; Belt, Simon T; Robert, Jean-Michel; Rowland, Steven J; Moldowan, J Michael; Barbanti, Silvana M; Fago, Frederick J; Denisevich, Peter; Dahl, Jeremy; Trindade, Luiz A F; Schouten, Stefan

    2004-04-23

    The 18S ribosomal DNA molecular phylogeny and lipid composition of over 120 marine diatoms showed that the capability to biosynthesize highly branched isoprenoid (HBI) alkenes is restricted to two specific phylogenetic clusters, which independently evolved in centric and pennate diatoms. The molecular record of C25 HBI chemical fossils in a large suite of well-dated marine sediments and petroleum revealed that the older cluster, composed of rhizosolenid diatoms, evolved 91.5 +/- 1.5 million years ago (Upper Turonian), enabling an accurate dating of the pace of diatom evolution that is unprecedented. The rapid rise of the rhizosolenid diatoms probably resulted from a major reorganization of the nutrient budget in the mid-Cretaceous oceans, triggered by plate tectonics.

  10. Sea-level rise and coastal wetlands.

    PubMed

    Blankespoor, Brian; Dasgupta, Susmita; Laplante, Benoit

    2014-12-01

    This paper seeks to quantify the impact of a1-m sea-level rise on coastal wetlands in 86 developing countries and territories. It is found that approximately 68 % of coastal wetlands in these countries are at risk. A large percentage of this estimated loss is found in Europe and Central Asia, East Asia, and the Pacific, as well as in the Middle East and North Africa. A small number of countries will be severely affected. China and Vietnam(in East Asia and the Pacific), Libya and Egypt (in the Middle East and North Africa), and Romania and Ukraine (in Europe and Central Asia) will bear most losses. In economic terms, the loss of coastal wetlands is likely to exceed $703 million per year in 2000 US dollars.

  11. Bubbles Rising Through a Soft Granular Material

    NASA Astrophysics Data System (ADS)

    Le Mestre, Robin; MacMinn, Chris; Lee, Sungyon

    2016-11-01

    Bubble migration through a soft granular material involves a strong coupling between the bubble dynamics and the deformation of the material. This is relevant to a variety of natural processes such as gas venting from sediments and gas exsolution from magma. Here, we study this process experimentally by injecting air bubbles into a quasi-2D packing of soft hydrogel beads and measuring the size, speed, and morphology of the bubbles as they rise due to buoyancy. Whereas previous work has focused on deformation resisted by intergranular friction, we focus on the previously inaccessible regime of deformation resisted by elasticity. At low confining stress, the bubbles are irregular and rounded, migrating via local rearrangement. At high confining stress, the bubbles become unstable and branched, migrating via pathway opening. The authors thank The Royal Society for support (International Exchanges Ref IE150885).

  12. Recent Results From MRO/HiRISE

    NASA Astrophysics Data System (ADS)

    McEwen, A. S.; Team, H. S.

    2008-12-01

    The High Resolution Imaging Science Experiment (HiRISE) on Mars Reconnaissance Orbiter (MRO) has acquired more than 7.8 Terapixels of Mars imaging since October 2006, covering less than 0.8% of the surface. Images are 5-6 km wide with 3-color coverage over the central 20%, and their scales usually range from 25-60 cm/pixel. More than 800 stereo pairs have been acquired and ~20 digital terrain models (DTMs) completed; these data have led to some of the most significant science results. New methods to measure and correct distortions due to pointing jitter facilitate topographic and change-detection studies at sub-meter scales. There are recent results concerning Noachian bedrock stratigraphy and megabreccia, fluvially- deposited fans in craters and in or near Valles Marineris, groundwater flow in fractures and porous media, quasi-periodic layering in polar and non-polar deposits, tectonic history of west Candor Chasm, geometry of clay-rich deposits near and within Mawrth Vallis, dynamics of flood lavas in the Cerberus Palus region, new evidence for pyroclastic deposits, columnar jointing in rapidly-cooled lava flows, recent collapse pits, evidence for water in well-preserved impact craters, newly-discovered large rayed craters, and glacial and periglacial processes. We are particularly interested in ongoing processes such as those driven by the wind, impact cratering, dust avalanches, icy avalanches on north polar scarps, relatively bright deposits on steep gullied slopes, and the especially dynamic seasonal processes over polar regions in the spring and summer. For landing sites (past, present, and future) HiRISE has acquired hundreds of large images and contributed to scientific and engineering studies.

  13. Numerical Investigation of Microgravity Tank Pressure Rise Due to Boiling

    NASA Technical Reports Server (NTRS)

    Hylton, Sonya; Ibrahim, Mounir; Kartuzova, Olga; Kassemi, Mohammad

    2015-01-01

    The ability to control self-pressurization in cryogenic storage tanks is essential for NASAs long-term space exploration missions. Predictions of the tank pressure rise in Space are needed in order to inform the microgravity design and optimization process. Due to the fact that natural convection is very weak in microgravity, heat leaks into the tank can create superheated regions in the liquid. The superheated regions can instigate microgravity boiling, giving rise to pressure spikes during self-pressurization. In this work, a CFD model is developed to predict the magnitude and duration of the microgravity pressure spikes. The model uses the Schrage equation to calculate the mass transfer, with a different accommodation coefficient for evaporation at the interface, condensation at the interface, and boiling in the bulk liquid. The implicit VOF model was used to account for the moving interface, with bounded second order time discretization. Validation of the models predictions was carried out using microgravity data from the Tank Pressure Control Experiment, which flew aboard the Space Shuttle Mission STS-52. Although this experiment was meant to study pressurization and pressure control, it underwent boiling during several tests. The pressure rise predicted by the CFD model compared well with the experimental data. The ZBOT microgravity experiment is scheduled to fly on February 2016 aboard the ISS. The CFD model was also used to perform simulations for setting parametric limits for the Zero-Boil-Off Tank (ZBOT) Experiments Test Matrix in an attempt to avoid boiling in the majority of the test runs that are aimed to study pressure increase rates during self-pressurization. *Supported in part by NASA ISS Physical Sciences Research Program, NASA HQ, USA

  14. Rising incidence of lymphoid malignancies--true or false?

    PubMed Central

    Barnes, N.; Cartwright, R. A.; O'Brien, C.; Richards, I. D.; Roberts, B.; Bird, C. C.

    1986-01-01

    The report contrasts the ascertainment of cases by the regional cancer registry with a specially designed search for records and pathology material which was then submitted to critical review irrespective of the original diagnosis. Boundary changes over the intervening years were accounted for and the results contrasted between time periods and with the cancer registry records. A large proportion of cancer registry cases were never subjected to histopathological diagnosis and comparisons between the new data and records are not easy to undertake. The study describes a probable true rise in the incidence of follicular non-Hodgkin's lymphoma in certain parts of Yorkshire over the last 20 years; there is less evidence of a similar change in Hodgkin's disease incidence over the same period of time. PMID:3964541

  15. Flare Emission Onset in the Slow-Rise and Fast-Rise Phases of an Erupting Solar Filament Observed with TRACE

    NASA Technical Reports Server (NTRS)

    Sterling, A. C.; Moore, R. L.

    2005-01-01

    We observe the eruption of an active-region solar filament of 1998 July 11 using high time cadence and high spatial resolution EUV observations from the TRACE sareiii'ce, along with soft X-ray images from the soft X-ray telescope (SXT) on the Yohkoh satellite, hard X-ray fluxes from the BATSE instrument on the (CGRO) satellite and from the hard X-ray telescope (HXT) on Yohkoh, and ground-based magnetograms. We concentrate on the initiation of the eruption in an effort to understand the eruption mechanism. First the filament undergoes slow upward movement in a "slow rise" phase with an approximately constant velocity of approximately 15 km/s that lasts about 10-min, and then it erupts in a "fast-rise" phase, reaching a velocity of about 200 km/s in about 5-min, followed by a period of deceleration. EUV brightenings begin just before the start of the filament's slow rise, and remain immediately beneath the rising filament during the slow rise; initial soft X-ray brightenings occur at about the same time and location. Strong hard X-ray emission begins after the onset of the fast rise, and does not peak until the filament has traveled a substantial altitude (to a height about equal to the initial length of the erupting filament) beyond its initial location. Our observations are consistent with the slow-rise phase of the eruption resulting from the onset of "tether cutting" reconnection between magnetic fields beneath the filament, and the fast rise resulting from an explosive increase in the reconnection rate or by catastrophic destabilization of the overlying filament-carrying fields. About two days prior to the event new flux emerged near the location of the initial brightenings, and this recently- emerged flux could have been a catalyst for initiating the tether-cutting reconnection. With the exception of the initial slow rise, our findings qualitatively agree with the prediction for erupting-flux-rope height as a function of time in a model discussed by Chen

  16. 46 CFR 111.20-5 - Temperature rise.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Temperature rise. 111.20-5 Section 111.20-5 Shipping... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The temperature rise, based on an ambient temperature of 40 degrees C, must not exceed the following: (1)...

  17. 46 CFR 111.20-5 - Temperature rise.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Temperature rise. 111.20-5 Section 111.20-5 Shipping... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The temperature rise, based on an ambient temperature of 40 degrees C, must not exceed the following: (1)...

  18. 46 CFR 111.20-5 - Temperature rise.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Temperature rise. 111.20-5 Section 111.20-5 Shipping... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The temperature rise, based on an ambient temperature of 40 degrees C, must not exceed the following: (1)...

  19. 46 CFR 111.20-5 - Temperature rise.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Temperature rise. 111.20-5 Section 111.20-5 Shipping... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The temperature rise, based on an ambient temperature of 40 degrees C, must not exceed the following: (1)...

  20. 46 CFR 111.20-5 - Temperature rise.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Temperature rise. 111.20-5 Section 111.20-5 Shipping... REQUIREMENTS Transformer Construction, Installation, and Protection § 111.20-5 Temperature rise. (a) The temperature rise, based on an ambient temperature of 40 degrees C, must not exceed the following: (1)...

  1. Modeling future sea level rise from melting glaciers

    NASA Astrophysics Data System (ADS)

    Radic, Valentina

    Melting mountain glaciers and ice caps (MG&IC) are the second largest contributor to rising sea level after thermal expansion of the oceans and are likely to remain the dominant glaciological contributor to rising sea level in the 21st century. The aim of this work is to project 21st century volume changes of all MG&IC and to provide systematic analysis of uncertainties originating from different sources in the calculation. I provide an ensemble of 21st century volume projections for all MG&IC from the World Glacier Inventory by modeling the surface mass balance coupled with volume-area-length scaling and forced with temperature and precipitation scenarios from four Global Climate Models (GCMs). By upscaling the volume projections through a regionally differentiated approach to all MG&IC outside Greenland and Antarctica (514,380 km 2) I estimated total volume loss for the time period 2001-2100 to range from 0.039 to 0.150 m sea level equivalent. While three GCMs agree that Alaskan glaciers are the main contributors to the projected sea level rise, one GCM projected the largest total volume loss mainly due to Arctic MG&IC. The uncertainties in the projections are addressed by a series of sensitivity tests applied in the methodology for assessment of global volume changes and on individual case studies for particular glaciers. Special emphasis is put on the uncertainties in volume-area scaling. For both, individual and global assessments of volume changes, the choice of GCM forcing glacier models is shown to be the largest source of quantified uncertainties in the projections. Another major source of uncertainty is the temperature forcing in the mass balance model depending on the quality of climate reanalysis products (ERA-40) in order to simulate the local temperatures on a mountain glacier or ice cap. Other uncertainties in the methods are associated with volume-area-length scaling as a tool for deriving glacier initial volumes and glacier geometry changes in the

  2. Cyclic fractionation processes beneath the Shatsky Rise oceanic plateau

    NASA Astrophysics Data System (ADS)

    Husen, A.; Almeev, R. R.; Holtz, F.

    2013-12-01

    Our understanding of the magma ascent, storage and differentiation beneath large igneous provinces (LIPs) is still under debate. Mainly two competing models are explaining the formation of LIPs: 1) the arrival of a deep sourced mantle plume in the lithosphere, and 2) decompression melting of unusually fusible mantle beneath fast-spreading ridges. The Shatsky Rise oceanic plateau is a unique opportunity to discuss this problem because its tectonic evolution along the Pacific-Farallon-Izanagi triple junction is well known. We examined samples recovered during IODP Expedition 324 at the Tamu Massif, one of three massifs of the Shatsky Rise. In general, the Shatsky Rise glasses are tholeiitic basalts containing 5 to 8.7 wt% MgO. Compared to MORB, the glass compositions are high in FeO (Fe8: 10.3) and low in SiO2 and Na2O (Na8: 1.9), indicating high amounts of partial melting at great depth. The CaO/Al2O3 ratios in the Tamu Massif evolved glasses are higher respectively to MORB indicating low pressure cotectic fractionation. In general, the basaltic glasses from Shatsky Rise show differentiation trends similar to those of other oceanic plateaus, as e.g. Ontong Java and Kerguelen. Pressures and temperatures of magma storage were estimated for 40 naturally quenched glasses (5-6.5 wt% MgO) along a drilled profile of 150 m length. Based on the glass major element compositions (electron microprobe) and glass H2O contents (infrared spectroscopy), we simulated the conditions of multiple saturation (Liq+Ol+Pl+Cpx) using the COMAGMAT program. The calculated pressures range from 240 MPa to 1 atm and the calculated temperatures range from 1150 to 1100 °C, indicating polybaric crystallization in a shallow magma reservoir. As a result, along the drilled profile, we identified two complete cycles of magma injection in the reservoir with subsequent fractionation and eruption followed by a time of magmatic inactivity. The most magnesian samples of the Shatsky Rise were drilled at Ori

  3. Rising soil temperature in China and its potential ecological impact

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Wang, Enli; Zhou, Daowei; Luo, Zhongkui; Zhang, Zhengxiang

    2016-10-01

    Global warming influences a series of ecological processes and ecosystems’ stability. Although comprehensive studies have been done to investigate responses of various ecosystem processes to rising air temperatures, less is known about changes in soil temperatures and their impact on below-ground processes, particularly in deep layers. Herein, we used 50 y of temperature data (1962–2011) from 360 sites in China to assess spatio-temporal changes in soil temperatures from the surface to a depth of 3.20 m. We determined, apparently for the first time, that soil surface temperature increased 31% more than air temperature, potentially leading to more carbon release to the atmosphere than predicted. Annual mean surface temperature increased by 2.07–4.04 and 0.66–2.21 °C in northern and southern China, respectively, with the greatest in winter. Warming occurred as deep as 3.20 m. The soil temperature rise was predicted to have increased soil respiration by up to 28%, reinforcing climate warming and extending the potential growing season by up to 20 d across China. However, use of only air temperature to estimate soil temperature changes would underestimate those impacts. In conclusion, these results highlighted the importance of soil warming and of using soil temperature to assess and predict soil processes.

  4. Mangrove sedimentation and response to relative sea-level rise

    USGS Publications Warehouse

    Woodroffe, CD; Rogers, K.; Mckee, Karen L.; Lovelock, CE; Mendelssohn, IA; Saintilan, N.

    2016-01-01

    Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions influence mangrove distributions, primarily related to elevation and hydroperiod; this review considers how these adjust through time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks; tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon, but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas Surface Elevation Table-Marker Horizon measurements (SET-MH) provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in continuing decline in their extent throughout the tropics.

  5. Rising soil temperature in China and its potential ecological impact

    PubMed Central

    Zhang, Hui; Wang, Enli; Zhou, Daowei; Luo, Zhongkui; Zhang, Zhengxiang

    2016-01-01

    Global warming influences a series of ecological processes and ecosystems’ stability. Although comprehensive studies have been done to investigate responses of various ecosystem processes to rising air temperatures, less is known about changes in soil temperatures and their impact on below-ground processes, particularly in deep layers. Herein, we used 50 y of temperature data (1962–2011) from 360 sites in China to assess spatio-temporal changes in soil temperatures from the surface to a depth of 3.20 m. We determined, apparently for the first time, that soil surface temperature increased 31% more than air temperature, potentially leading to more carbon release to the atmosphere than predicted. Annual mean surface temperature increased by 2.07–4.04 and 0.66–2.21 °C in northern and southern China, respectively, with the greatest in winter. Warming occurred as deep as 3.20 m. The soil temperature rise was predicted to have increased soil respiration by up to 28%, reinforcing climate warming and extending the potential growing season by up to 20 d across China. However, use of only air temperature to estimate soil temperature changes would underestimate those impacts. In conclusion, these results highlighted the importance of soil warming and of using soil temperature to assess and predict soil processes. PMID:27765953

  6. Rising variance: a leading indicator of ecological transition.

    PubMed

    Carpenter, S R; Brock, W A

    2006-03-01

    Regime shifts are substantial, long-lasting reorganizations of complex systems, such as ecosystems. Large ecosystem changes such as eutrophication, shifts among vegetation types, degradation of coral reefs and regional climate change often come as surprises because we lack leading indicators for regime shifts. Increases in variability of ecosystems have been suggested to foreshadow ecological regime shifts. However, it may be difficult to discern variability due to impending regime shift from that of exogenous drivers that affect the ecosystem. We addressed this problem using a model of lake eutrophication. Lakes are subject to fluctuations in recycling associated with regime shifts, as well as fluctuating nutrient inputs. Despite the complications of noisy inputs, increasing variability of lake-water phosphorus was discernible prior to the shift to eutrophic conditions. Simulations show that rising standard deviation (SD) could signal impending shifts about a decade in advance. The rising SD was detected by studying variability around predictions of a simple time-series model, and did not depend on detailed knowledge of the actual ecosystem dynamics.

  7. Mangrove Sedimentation and Response to Relative Sea-Level Rise.

    PubMed

    Woodroffe, C D; Rogers, K; McKee, K L; Lovelock, C E; Mendelssohn, I A; Saintilan, N

    2016-01-01

    Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions, related primarily to elevation and hydroperiod, influence mangrove distributions; this review considers how these distributions change over time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks, and tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas measurements made using surface elevation tables and marker horizons provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in a continuing decline in their extent throughout the tropics.

  8. Mangrove Sedimentation and Response to Relative Sea-Level Rise

    NASA Astrophysics Data System (ADS)

    Woodroffe, C. D.; Rogers, K.; McKee, K. L.; Lovelock, C. E.; Mendelssohn, I. A.; Saintilan, N.

    2016-01-01

    Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions, related primarily to elevation and hydroperiod, influence mangrove distributions; this review considers how these distributions change over time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks, and tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas measurements made using surface elevation tables and marker horizons provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in a continuing decline in their extent throughout the tropics. *

  9. Capillary rise in Hele-Shaw models of disordered media.

    PubMed

    Clotet, Xavier; Planet, Ramon; Ortín, Jordi

    2012-07-01

    We study the capillary rise of a viscous liquid in large Hele-Shaw models of disordered media, both analytically and experimentally. Compared to the Fries-Dreyer and Lucas-Washburn solutions for capillary rise with and without gravity, our experimental data reveal a systematic deviation at short and intermediate times. The original pressure balance equation leading to Washburn's results is reformulated in order to include an additional resisting term, proportional to the mean velocity of the front h˙, which appears naturally as a result of the geometry of the cell. Analytical solutions h(t) are found for displacements with and without gravity. These new solutions reproduce the experimental results very accurately in Hele-Shaw cells of constant gap thickness, where the capillary pressure can be approximated by a constant. In cells of fluctuating gap thickness, where the capillary pressure fluctuates in space, a small additional pressure contribution is required. This correction that depends on h˙ is also studied.

  10. A computational study of the dynamic motion of a bubble rising in Carreau model fluids

    NASA Astrophysics Data System (ADS)

    Ohta, Mitsuhiro; Yoshida, Yutaka; Sussman, Mark

    2010-04-01

    We present the results of three-dimensional direct numerical simulations of the dynamic motion of a gas bubble rising in Carreau model fluids. The simulations are carried out by a coupled level-set/volume-of-fluid (CLSVOF) method, which combines some of the advantages of the volume-of-fluid (VOF) method with the level-set (LS) method. In our study, it is shown that the motion of a rising gas bubble largely depends on the Carreau model parameters, n and B (n, the slope of decreasing viscosity and B, time constant). Both the model parameters, n and B, have considerable influence on the bubble rise motion. Using numerical analysis, we can understand in detail the bubble morphology for non-Newtonian two-phase flow systems. We also discuss bubble rise motion in shear-thinning fluids in terms of the effective viscosity, ηeff, the effective Reynolds number, Reeff and the effective Morton number, Meff.

  11. A statistical study of EMIC rising and falling tone emissions observed by THEMIS

    NASA Astrophysics Data System (ADS)

    Nakamura, Satoko; Omura, Yoshiharu; Angelopoulos, Vassilis

    2016-09-01

    Electromagnetic ion cyclotron (EMIC) waves with rising or falling frequency variations have been studied intensively because of their effects on energetic particles in the Earth's magnetosphere. We develop an automated classification method of EMIC events based on the characteristics of frequency variations. We report some basic statistical properties of frequency variations in EMIC waves observed over 5-10 RE by three Time History of Events and Macroscale Interactions during Substorms probes from January 2012 to December 2014. We clarify whether rising tones or falling tones are observed in each chosen 20 min time segment. In the present analysis, we find that the occurrence rate of EMIC rising or falling tone events is more than 30% of the total EMIC wave events. The dayside magnetosphere is a preferential region for the EMIC frequency variations. The occurrence rate of rising tone events is slightly greater than that of falling tone events. We examine the relation between the frequency characteristics and the magnetospheric conditions. The solar wind pressure strongly controls the occurrence rates of frequency variations. We also calculate ranges of frequency variations. Large-amplitude EMIC waves tend to have wider frequency variations, and the range of frequency variation is largest around the prenoon region. In addition, rapid variations in wave amplitudes called "subpacket structures" are found in 70% of the EMIC rising or falling tone events in the dayside region. Subpacket structures appear mainly in large-amplitude EMIC rising or falling tones. These features are consistent with nonlinear wave growth theory.

  12. Northern east Pacific rise: Magnetic anomaly and bathymetric framework

    SciTech Connect

    Klitgord, K.D.; Mammerickx, J.

    1982-08-10

    The oceanic crust in the eastern Pacific between 7/sup 0/N and 30/sup 0/N and east of 127/sup 0/W contains a fairly complete history of the spreading centers associated with the East Pacific Rise since 25 m.y. B.P. (late Oligocene). In this paper, we have summarized the seafloor spreading magnetic-anomaly data and the bathymetric data that reflect the record of this technique history. The well-defined magnetic lineations north of the Clarion fracture zone, in the mouth of the Gulf of California, and on the east flank of the East Pacific Rise (EPR) are carefully examined and used to provide a guide for interpreting the spreading pattern between the Clarion and Clipperton fracture zones, southward of the Rivera fracture zone over the Mathematician Ridge, and over the entire EPR east of the Mathematician Ridge between the Rivera and Siqueiros fracture zones. The bathymetric data provide a trace of the fracture zone pattern in each of the above mentioned areas. The fracture zone bathymetry and the seafloor spreading magnetc lineations on the EPR south of the Rivera fracture zone have a distinctive fanning pattern caused by close poles of rotation and plate boundary reorganizations. All these data provide a good record of the plate reorganizations in the middle Miocene at magnetic anomaly 5A time (12.5 to 11 m.y. B.P.), in the late Miocene at a magnetic anomaly 3'--4 time (6.5 m.y. B.P.), and in the Pliocene at magnetic anomaly 2'--3 time (3.5 m.y.B.P.). Several abandoned spreading centers, including the Mathematician Ridge, were left behind as a result of these reorganizations. The Mathematician Ridge is shown to be a set of ridges and trough whose origin is related to the tectonics activity associated with each of the above mentioned reorganizations since anomaly 5A.

  13. China's birth rate reported on rise.

    PubMed

    Haupt, A

    1987-05-01

    China's birth rate reportedly rose in 1986, reversing a long-term trend toward low fertility. The results of a 1986 survey indicate that China's birth rate increased from 18/1000 population in 1985 to 20.8/1000 in 1986, consistent with a total fertility rate of 2.4 births/woman. In part, the birth rate increase reflects changes in China's age structure--a baby boom "echo" as the large cohorts of 1962-64 reach reproductive age. Another factor may have been the new marriage law of 1980 which lowered the marriage age to 20 years for women and 22 years for men. Aggressive implementation of China's population program in the 1980s was punctuated by periods of intermittent policy relaxation and exception-granting of the 1-child standard. Surveys from different parts of the country have documented popular interest in having 2 or more children. Finally, the increased fertility may be an effect of recent social and economic changes. The emphasis on economic development and modernization is creating new migrant populations in urban areas who are slipping through the system in terms of fertility surveillance. In addition, the privatization of agriculture is encouraging farmers to increase their productivity, and thus creating a demand for larger family size. It is unclear whether the apparent rise in China's birth rate is an anomaly or a harbinger of future fertility trends. However, China's fertility change is enough to increase the world's birth rate by 1 in 1987.

  14. China's rising hydropower demand challenges water sector.

    PubMed

    Liu, Junguo; Zhao, Dandan; Gerbens-Leenes, P W; Guan, Dabo

    2015-07-09

    Demand for hydropower is increasing, yet the water footprints (WFs) of reservoirs and hydropower, and their contributions to water scarcity, are poorly understood. Here, we calculate reservoir WFs (freshwater that evaporates from reservoirs) and hydropower WFs (the WF of hydroelectricity) in China based on data from 875 representative reservoirs (209 with power plants). In 2010, the reservoir WF totaled 27.9 × 10(9) m(3) (Gm(3)), or 22% of China's total water consumption. Ignoring the reservoir WF seriously underestimates human water appropriation. The reservoir WF associated with industrial, domestic and agricultural WFs caused water scarcity in 6 of the 10 major Chinese river basins from 2 to 12 months annually. The hydropower WF was 6.6 Gm(3) yr(-1) or 3.6 m(3) of water to produce a GJ (10(9) J) of electricity. Hydropower is a water intensive energy carrier. As a response to global climate change, the Chinese government has promoted a further increase in hydropower energy by 70% by 2020 compared to 2012. This energy policy imposes pressure on available freshwater resources and increases water scarcity. The water-energy nexus requires strategic and coordinated implementations of hydropower development among geographical regions, as well as trade-off analysis between rising energy demand and water use sustainability.

  15. Iraqi crude exports may rise further

    SciTech Connect

    Not Available

    1980-12-08

    Iraq will soon start exporting crude oil through a 550 mi, 500,000 bbl/day capacity pipeline from Iraq to Banias, Syria, on the Mediterranean. Iraq has already been transporting a reported 400,000 bbl/day in a 700,000 bbl/day capacity pipeline that goes to Dortyol, Turk., on the Mediterranean. Iraq's theoretical export capacity will soon reach 1.2 million bbl/day (compared with 3.2 million bbl/day before the war), assuming that the facilities are undamaged. Iran has been exporting some crude from its Kharg Island terminal, presumably by Iranian boat to the Lavan Island terminal at the southern end of the gulf, where it would be transported along with crude from offshore fields in the area. The exports apparently had been large enough to keep spot-market prices from rising much above the $40/bbl level, and in Dec. 1980, the spot-market prices eased to just under the $40 mark. Indonesia has raised the premium on its Sumatran light crude by $1/bbl, bringing the total to $35.20. Other producers have not yet raised their prices correspondingly. The agenda of the Dec. 1980 price-fixing meeting in Indonesia (assuming it takes place as planned) is discussed.

  16. Skin stem cells: rising to the surface.

    PubMed

    Fuchs, Elaine

    2008-01-28

    The skin epidermis and its appendages provide a protective barrier that is impermeable to harmful microbes and also prevents dehydration. To perform their functions while being confronted with the physicochemical traumas of the environment, these tissues undergo continual rejuvenation through homeostasis, and, in addition, they must be primed to undergo wound repair in response to injury. The skin's elixir for maintaining tissue homeostasis, regenerating hair, and repairing the epidermis after injury is its stem cells, which reside in the adult hair follicle, sebaceous gland, and epidermis. Stem cells have the remarkable capacity to both self-perpetuate and also give rise to the differentiating cells that constitute one or more tissues. In recent years, scientists have begun to uncover the properties of skin stem cells and unravel the mysteries underlying their remarkable capacity to perform these feats. In this paper, I outline the basic lineages of the skin epithelia and review some of the major findings about mammalian skin epithelial stem cells that have emerged in the past five years.

  17. Enhancing capillary rise on a rough surface

    NASA Astrophysics Data System (ADS)

    Chow, Melissa; Wexler, Jason; Jacobi, Ian; Stone, Howard

    2014-11-01

    Liquid-infused surfaces have been proposed as a robust alternative to traditional air-cushioned superhydrophobic surfaces. However, if these surfaces are held vertically the lubricating oil can drain from the surface, and cause the surface to lose its novel properties. To examine this failure mode, we measure the drainage from a surface with model roughness that is scaled-up to allow for detailed measurements. We confirm that the bulk fluid drains from the surface until it reaches the level of the capillary rise height, although the detailed dynamics vary even in simple surface geometries. We then test different substrate architectures to explore how the roughness can be designed to retain greater amounts of oil. Supported under MRSEC NSF DMR 0819860 (PI: Prof. N. Phuan Ong) REU Site Grant: NSF DMR-1156422 (PI: Prof. Mikko Haataja), PREM CSUN Prime # NSF 1205734 and ONR MURI Grants N00014-12-1-0875 and N00014-12-1-0962 (Program Manager Dr. Ki-Han Kim).

  18. Developing a Coastal Risk Indicator for Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Masters, D. S.; Nerem, R.

    2012-12-01

    Coastal sea level rise is one the most important potential environmental risks. Multiple satellite altimeters flying on the same repeat orbit track have allowed estimation of global mean sea level for the past 20 years, and the time series has yielded information about the average rate of sea level increase over that time. Due to the duration, consistency, and inter-calibration of the altimeter measurements, the time series is now considered a climate record. The time series has also shown the strong dependence of sea level on interannual signals such as the ENSO and the NAO. But the most important sea level effects of climate change will be felt on the regional and local scales. At these smaller scales, local effects due to topography, tides, earth deformation (glacial isostatic adjustment (GIA), subsidence, etc.), and storm surges must also be considered when estimating the risks of sea level change to coastal communities. Recently, work has begun to understand the methods applicable to estimating the risks of expected sea level change to coastal communities (Strauss et al., 2012; Tebaldi et al., 2012). Tebaldi et al (2012) merged the expected global mean sea level increase from the semi-empirical model of Vermeer and Rahmstorf (2009) with historical local tide gauges to predict increases in storm surge risk posed by increasing sea level. In this work, we will further explore the currently available data and tools that can potentially be used to provide a sea level climate change indicator and local risk assessment along US coasts. These include global and regional sea level trends from the satellite altimetry climate record, in situ tide gauge measurements and the historical extremes at each location, local tide and storm surge models, topographic surveys of vulnerable coastlines, GIA models, and measurements of local subsidence and crustal deformation rates. We will also evaluate methods to estimate the increased risk to communities from sea level change

  19. Volcanic rocks cored on hess rise, Western Pacific Ocean

    USGS Publications Warehouse

    Vallier, T.L.; Windom, K.E.; Seifert, K.E.; Thiede, Jorn

    1980-01-01

    Large aseismic rises and plateaus in the western Pacific include the Ontong-Java Plateau, Magellan Rise, Shatsky Rise, Mid-Pacific Mountains, and Hess Rise. These are relatively old features that rise above surrounding sea floors as bathymetric highs. Thick sequences of carbonate sediments overlie, what are believed to be, Upper Jurassic and Lower Cretaceous volcanic pedestals. We discuss here petrological and tectonic implications of data from volcanic rocks cored on Hess Rise. The data suggest that Hess Rise originated at a spreading centre in the late early Cretaceous (Aptian-Albian stages). Subsequent off-ridge volcanism in the late Albian-early Cenomanian stages built a large archipelago of oceanic islands and seamounts composed, at least in part, of alkalic rocks. The volcanic platform subsided during its northward passage through the mid-Cretaceousequatorial zone. Faulting and uplift, and possibly volcanism, occurred in the latest Cretaceous (Campanian-Maastrichtian stages). Since then, Hess Rise continued its northward movement and subsidence. Volcanic rocks from holes drilled on Hess Rise during IPOD Leg 62 (Fig. 1) are briefly described here and we relate the petrological data to the origin and evolution of that rise. These are the first volcanic rocks reported from Hess Rise. ?? 1980 Nature Publishing Group.

  20. Capillary rise in a tilted Taylor-Hauksbee cell

    NASA Astrophysics Data System (ADS)

    Medina, Abraham; Klapp, Jaime; Torres Victoria, Ayax Hernando; Peralta Lopez, Salomon; Jara Hernandez, Aydet

    2015-11-01

    The penetration of a wetting liquid in the narrow gap between two tilted plates making a small angle among them is analyzed in the framework of the lubrication approximation. At the beginning of the process, the liquid rises independently at different distances from the line of intersection of the plates. The maximum height of the liquid initially increases as a power law of time, where the exponent is dependent on the angle of inclination of the plates and is attained at a point that reaches the line of intersection only after a certain time. At later times, the motion of the liquid is confined to a thin layer around the line of intersection whose height increases again as a power law of time and the exponent of the power law is a function of the angle of inclination. The thickness of the film decreases as the inverse of the power law of time. The evolution of the liquid surface is computed numerically and compared with the results of simple experiments.

  1. Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle

    PubMed Central

    1977-01-01

    The effect of shortening on contractile activity was studied in experiments in which shortening during the rising phase of an isotonic contraction was suddenly stopped. At the same muscle length and the same time after stimulation the rise in tension was much faster, if preceded by shortening, than during an isometric contraction, demonstrating an increase in contractile activity. In this experiment the rate of tension rise determined in various phases of contraction was proportional to the rate of isotonic shortening at the same time after stimulation. Therefore, the time course of the isotonic rising phase could be derived from the tension rise after shortening. The rate of isotonic shortening was found to be unrelated to the tension generated at various lengths and to correspond closely to the activation process induced by shortening. The length response explains differences between isotonic and isometric contractions with regard to energy release (Fenn effect) and time relations. These results extend previous work which showed that shortening during later phases of a twitch prolongs, while lengthening abbreviates contraction. Thus the length responses, which have been called shortening activation and lengthening deactivation, control activity throughout an isotonic twitch. PMID:591919

  2. Time-resolved diode laser infrared absorption spectroscopy of the nascent HCl in the infrared laser chemistry of 1,2-dichloro-1,1-difluoroethane

    NASA Astrophysics Data System (ADS)

    Dietrich, Peter; Quack, Martin; Seyfang, George

    1990-04-01

    The IR multiphoton excitation and the frequency, fluence and intensity dependence of the IR-laser chemical yields of CF 2ClCH 2Cl have been studied in the fluence range of 1 to 10 J cm -2 yielding a steady-state constant k(st)/ I=0.74×10 6 s -1 MW -1 cm 2 which is approximately independent of intensity. Time-resolved IR absorption spectroscopy with diode laser sources has been used to observe the nascent HCl during the first few 100 ns indicating a population inversion between the levels ν=1, J=4 and ν=2, J=5. At low reactant pressures ( p⩽10 Pa) the time-resolved measurement gives a steady-state rate constant consistent with the theoretical result adjusted to the static yield measurements. The capability of state-selective and time-resolved IR spectroscopy is thus demonstrated, giving real-time determinations of rate constants.

  3. Prediction of surface temperature rise of ultrasonic diagnostic array transducers.

    PubMed

    Ohm, Won-Suk; Kim, Jeong Hwan; Kim, Eun Chul

    2008-01-01

    Temperature rise at the surface of an ultrasound transducer used for diagnostic imaging is an important factor in patient safety and regulatory compliance. This paper presents a semianalytical model that is derived from first principles of heat transfer and is simple enough to be implemented in a commercial ultrasound scanner for real-time forecasting of transducer surface temperature. For modeling purposes, one-dimensional array transducers radiating into still air are considered. Promising experimental verification data are shown and practical implementation benefits of the model for thermal design and management of ultrasonic array transducers are discussed. In particular, the reduction in the amount of thermal characterization data required, compared to empirical models, shows promise.

  4. Modeling rises and falls in money addicted social hierarchies

    NASA Astrophysics Data System (ADS)

    Dybiec, Bartłomiej; Mitarai, Namiko; Sneppen, Kim

    2014-08-01

    The emergence of large communities is inherently associated with the creation of social structures. Connections between individuals are indispensable for cooperative action of agents building social groups. Moreover, social groups usually evolve and their structure changes over time. Consequently, an underlying network connecting individuals is not static, reflecting an ongoing adaptation to new conditions. The evolution of social connections is influenced by the relative position (hierarchy) of individuals building the system as well as by the availability of resources. We explore this aspect of human ambition by modeling the interplay of social networking and an uneven distribution of external resources. The model naturally generates social hierarchies. Remarkably, this social structure exhibits a rise-and-fall behavior. A well pronounced quasi-periodic dynamics, which is closely associated with the dissipation of resources that are needed to sustain the social links, is revealed.

  5. Rising dough and baking bread at the Australian synchrotron

    NASA Astrophysics Data System (ADS)

    Mayo, S. C.; McCann, T.; Day, L.; Favaro, J.; Tuhumury, H.; Thompson, D.; Maksimenko, A.

    2016-01-01

    Wheat protein quality and the amount of common salt added in dough formulation can have a significant effect on the microstructure and loaf volume of bread. High-speed synchrotron micro-CT provides an ideal tool for observing the three dimensional structure of bread dough in situ during proving (rising) and baking. In this work, the synchrotron micro-CT technique was used to observe the structure and time evolution of doughs made from high and low protein flour and three different salt additives. These experiments showed that, as expected, high protein flour produces a higher volume loaf compared to low protein flour regardless of salt additives. Furthermore the results show that KCl in particular has a very negative effect on dough properties resulting in much reduced porosity. The hundreds of datasets produced and analysed during this experiment also provided a valuable test case for handling large quantities of data using tools on the Australian Synchrotron's MASSIVE cluster.

  6. Relativistic rise measurements with very fine sampling intervals

    SciTech Connect

    Ludlam, T.; Platner, E.D.; Polychronakos, V.A.; Lindenbaum, S.J.; Kramer, M.A.; Teramoto, Y.

    1980-01-01

    The motivation of this work was to determine whether the technique of charged particle identification via the relativistic rise in the ionization loss can be significantly improved by virtue of very small sampling intervals. A fast-sampling ADC and a longitudinal drift geometry were used to provide a large number of samples from a single drift chamber gap, achieving sampling intervals roughly 10 times smaller than any previous study. A single layer drift chamber was used, and tracks of 1 meter length were simulated by combining together samples from many identified particles in this detector. These data were used to study the resolving power for particle identification as a function of sample size, averaging technique, and the number of discrimination levels (ADC bits) used for pulse height measurements.

  7. [The rise and fall of an physician entrepreneur].

    PubMed

    Dörnyei, Sándor

    2002-01-01

    In 1927 one of the most up-to-date and most beautiful sanatoriums of Central Europe was built on the hills of Buda by László Jakab MD (1875-1940), who at that time had already run - since 1909 - a successful health-resort, the rather popular and successful "Liget-Sanatorium": following a period of expansion and flourishing, his enterprise bankrupted. (The building itself was renewed after World War II - it served first as a hospital for tuberculosis patients and later as a university clinic for internal medicine.) This article tells the story of an entrepreneur physician, including his former and more successful attempts to run a health-care business, and gives detailed account of the rise and fall of private health-resort in prewar Hungary.

  8. Anomalous dynamics of capillary rise in porous media.

    PubMed

    Shikhmurzaev, Yulii D; Sprittles, James E

    2012-07-01

    The anomalous dynamics of capillary rise in a porous medium discovered experimentally more than a decade ago [T. Delker et al., Phys. Rev. Lett. 76, 2902 (1996)] is described. The developed theory is based on considering the principal modes of motion of the menisci that collectively form the wetting front on the Darcy scale. These modes, which include (i) dynamic wetting mode, (ii) threshold mode, and (iii) interface depinning process, are incorporated into the boundary conditions for the bulk equations formulated in the regular framework of continuum mechanics of porous media, thus allowing one to consider a general case of three-dimensional flows. The developed theory makes it possible to describe all regimes observed in the experiment, with the time spanning more than four orders of magnitude, and highlights the dominant physical mechanisms at different stages of the process.

  9. The rise and fall of gluten!

    PubMed

    Aziz, Imran; Branchi, Federica; Sanders, David S

    2015-08-01

    Mankind has existed for 2·5 million years but only in the last 10,000 years have we been exposed to wheat. Wheat was first cultivated in the Fertile Crescent (South Western Asia) with a farming expansion that lasted from about 9000BC to 4000BC. Thus it could be considered that wheat (and gluten) is a novel introduction to man's diet! Prior to 1939 the rationing system had already been devised. This led to an imperative to try to increase agricultural production. Thus it was agreed in 1941 that there was a need to establish a Nutrition Society. The very roots of the society were geared towards necessarily increasing the production of wheat. This goal was achieved and by the end of the 20th century, global wheat output had expanded 5-fold. Perhaps as a result the epidemiology of coeliac disease (CD) or gluten sensitive enteropathy has changed. CD is a state of heightened immunological responsiveness to ingested gluten in genetically susceptible individuals. CD now affects 1 % or more of all adults, for which the treatment is a strict lifelong gluten-free diet. However, there is a growing body of evidence to show that a far greater proportion of individuals without coeliac disease are taking a gluten-free diet of their own volition. This clinical entity has been termed non-coeliac gluten sensitivity (NCGS), although the condition is fraught with complexities due to overlap with other gluten-based constituents that can also trigger similar clinical symptoms. This review will explore the relationship between gluten, the rising prevalence of modern coeliac disease, and the new entity of NCGS along with its associated uncertainties.

  10. Computational Fluid Dynamics of rising droplets

    SciTech Connect

    Wagner, Matthew; Francois, Marianne M.

    2012-09-05

    The main goal of this study is to perform simulations of droplet dynamics using Truchas, a LANL-developed computational fluid dynamics (CFD) software, and compare them to a computational study of Hysing et al.[IJNMF, 2009, 60:1259]. Understanding droplet dynamics is of fundamental importance in liquid-liquid extraction, a process used in the nuclear fuel cycle to separate various components. Simulations of a single droplet rising by buoyancy are conducted in two-dimensions. Multiple parametric studies are carried out to ensure the problem set-up is optimized. An Interface Smoothing Length (ISL) study and mesh resolution study are performed to verify convergence of the calculations. ISL is a parameter for the interface curvature calculation. Further, wall effects are investigated and checked against existing correlations. The ISL study found that the optimal ISL value is 2.5{Delta}x, with {Delta}x being the mesh cell spacing. The mesh resolution study found that the optimal mesh resolution is d/h=40, for d=drop diameter and h={Delta}x. In order for wall effects on terminal velocity to be insignificant, a conservative wall width of 9d or a nonconservative wall width of 7d can be used. The percentage difference between Hysing et al.[IJNMF, 2009, 60:1259] and Truchas for the velocity profiles vary from 7.9% to 9.9%. The computed droplet velocity and interface profiles are found in agreement with the study. The CFD calculations are performed on multiple cores, using LANL's Institutional High Performance Computing.

  11. A Historical Educational Reform: Turkey Rising

    ERIC Educational Resources Information Center

    Sad, Suleyman Nihat; Battal, Nevzat

    2008-01-01

    This article aims at scrutinizing an example of how education can help a whole nation survive the most fateful times in its history: a world war followed by a struggle for independence. Therefore, the latest times of the Ottoman Empire in general and Ottoman education in particular are outlined to illustrate what the young Turkish republic…

  12. A Hydro-marsh equilibrium model for marsh system response to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Alizad, K.; Hagen, S. C.; Morris, J. T.; Bacopoulos, P.

    2013-12-01

    In this study, an integrated model to assess the effect of sea level rise on salt marsh systems is presented. It is based on a coupled two-dimensional hydrodynamic model and a parametric marsh model. The model shows marsh productivity as a function of mean high water (MHW), mean low water (MLW), and the elevation of the marsh platform. MHW and MLW are the mean high and low water levels over a tidal record and the marsh platform elevation is the elevation of the thick and smooth piled up sediments and biomass that support the productivity of the marsh. MHW and MLW throughout a river and tidal creeks are determined by time varying tides resulting from the two-dimensional hydrodynamic model. In order to calculate accurate biomass productivity, and MHW and MLW elevations, a digital elevation model (DEM) representing the marsh table elevation and tidal creeks with high accuracy is necessary (Hagen et al., 2013). There are optimum ranges for relative sea level rise (RSLR), mean sea level (MSL), and depth of inundation for salt marshes to increase productivity. Because of the constantly changing MSL, the marsh always adjusts itself to a new equilibrium (Morris, et al., 2002). In the marsh model, the sediment accretion rate, which is a function of the marsh productivity, is considered. The tidal record is calculated by the hydrodynamic model and the DEM is adjusted by incorporating the accretion rate over a period of time, provided by the marsh model. Then, the new tidal record is assessed by running the hydrodynamic model, considering sea level rise with the new marsh table elevations. Using the new tidal record, the marsh productivity is simulated. This process can be divided into short time steps to capture changes in the rate of sea level rise. For example, a 68 cm sea level rise over 63 years can be split into five- or ten- year periods to have a linear trend for sea level rise in each period. The model is examined for the lower St. Johns River and Apalachicola River

  13. Preferential Amplification of Rising Versus Falling Frequency Whistler-Mode Signals

    NASA Astrophysics Data System (ADS)

    Li, J.; Harid, V.; Spasojevic, M.; Golkowski, M.; Inan, U.

    2014-12-01

    Analysis of ground-based ELF/VLF observations of injected whistler-mode waves from the 1986 Siple Station experiment indicate a distinct preference for the magnetospheric amplification of rising frequency-time ramps over descending frequency-time ramps. In examining conjugate region receptions of ±1 kHz/sec frequency ramps, we find that the rising ramps generate a total power that is on average 1.9 times higher than that of falling frequency ramps when both are observed within a given transmission. Also, in 17% of receptions, only the rising frequency ramps are observed, and the descending ramps are below the detectable signal level. Using a narrowband Vlasov-Maxwell numerical simulation, we explore the preferential amplification of rising ramps due to differences in the linear growth rate as a function of frequency and the onset and duration of nonlinear phase trapping. These results contribute to the understanding of magnetospheric wave amplification and the formation of structured rising elements in chorus.

  14. SEA-LEVEL RISE. Sea-level rise due to polar ice-sheet mass loss during past warm periods.

    PubMed

    Dutton, A; Carlson, A E; Long, A J; Milne, G A; Clark, P U; DeConto, R; Horton, B P; Rahmstorf, S; Raymo, M E

    2015-07-10

    Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak sea level during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust sea-level estimates for intervals such as the Pliocene. Present climate is warming to a level associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo-sea level records.

  15. Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise

    USGS Publications Warehouse

    Hatfield, Jeff S.; Reynolds, Michelle H.; Seavy, Nathaniel E.; Krause, Crystal M.

    2012-01-01

    Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds.

  16. Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise.

    PubMed

    Hatfield, Jeff S; Reynolds, Michelle H; Seavy, Nathaniel E; Krause, Crystal M

    2012-08-01

    Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds.

  17. A cellular automaton model for the rise of magma

    NASA Astrophysics Data System (ADS)

    Piegari, Ester; di Maio, Rosa; Milano, Leopoldo; Scandone, Roberto

    2010-05-01

    Eruptions of volcanoes are complex natural events highly variable in size and time. Over the last couple of decades, statistical analyses of erupted volume and repose time catalogues have been performed for a large number of volcanoes. The aim of such analyses is either to predict future eruptive events or to define physical models for improving our understanding of the volcanic processes that cause eruptions. In particular, for this latter purpose we study a statistical model of eruption triggering caused by the fracturing of the crust above a magma reservoir residing in the crust. When the fracturing reaches the reservoir, magma is allowed to ascend because of its buoyancy. It will be found in batches along the transport region and it will ascend as long as fractures are developed to its tip; when a path is opened to the surface, an eruption occurs involving all batches connected to the opening. We model the vertical section of a volcanic edifice by means of a two-dimensional grid and characterize the state of each cell of the grid by assigning the values of two dynamical variables: a time dependent variable e describing the status of the local stress and a time-dependent variable n describing the presence of magma. At first step of approximation, we treat the magma presence field n as a diffusing lattice gas, and, therefore, we assume its value to be either zero or one if the corresponding cell is empty or filled by magma, respectively. We study the probability distribution, P(V), of eruptions of volume V and the probability distribution, P(t), of inter-event time t and find that the model is able to reproduce, at least in a descriptive way, the essential statistical features of the activity of volcanoes. A key component of magma is the quantity of dissolved gas as it gives magma its explosive character, because the volume of gas expands as the pressure decreases on raising towards the surface. Then, to more accurately describe the rise of magma in a volcanic

  18. The rise of oxygen and aerobic biochemistry.

    PubMed

    Saito, Mak A

    2012-01-11

    Analysis of conserved protein folding domains across extant genomes by Kim et al. in this issue of Structure provides insights into the timing of some of the earliest aerobic metabolisms to arise on Earth.

  19. Most wired. CMIOs steadily on the rise.

    PubMed

    McKinney, Maureen

    2010-03-01

    These tech-savvy physicians will play a big role as meaningful use requirements put more emphasis on integrating IT and quality. Just asking doctors to volunteer some time to serve on a committee "just doesn't fly anymore".

  20. Swarm dynamics may give rise to Lévy flights

    PubMed Central

    Reynolds, Andrew M.; Ouellette, Nicholas T.

    2016-01-01

    “Continuous-time correlated random walks” are now gaining traction as models of scale-finite animal movement patterns because they overcome inherent shortcomings with the prevailing paradigm - discrete random walk models. Continuous-time correlated random walk models are founded on the classic Langevin equation that is driven by purely additive noise. The Langevin equation is, however, changed fundamentally by the smallest of multiplicative noises. The inclusion of such noises gives rise to Lévy flights, a popular but controversial model of scale-free movement patterns. Multiplicative noises have not featured prominently in the literature on biological Lévy flights, being seen, perhaps, as no more than a mathematical contrivance. Here we show how Langevin equations driven by multiplicative noises and incumbent Lévy flights arise naturally in the modelling of swarms. Model predictions find some support in three-dimensional, time-resolved measurements of the positions of individual insects in laboratory swarms of the midge Chironomus riparius. We hereby provide a new window on Lévy flights as models of movement pattern data, linking patterns to generative processes. PMID:27465971

  1. The social values at risk from sea-level rise

    SciTech Connect

    Graham, Sonia; Barnett, Jon; Fincher, Ruth; Hurlimann, Anna; Mortreux, Colette; Waters, Elissa

    2013-07-15

    Analysis of the risks of sea-level rise favours conventionally measured metrics such as the area of land that may be subsumed, the numbers of properties at risk, and the capital values of assets at risk. Despite this, it is clear that there exist many less material but no less important values at risk from sea-level rise. This paper re-theorises these multifarious social values at risk from sea-level rise, by explaining their diverse nature, and grounding them in the everyday practices of people living in coastal places. It is informed by a review and analysis of research on social values from within the fields of social impact assessment, human geography, psychology, decision analysis, and climate change adaptation. From this we propose that it is the ‘lived values’ of coastal places that are most at risk from sea-level rise. We then offer a framework that groups these lived values into five types: those that are physiological in nature, and those that relate to issues of security, belonging, esteem, and self-actualisation. This framework of lived values at risk from sea-level rise can guide empirical research investigating the social impacts of sea-level rise, as well as the impacts of actions to adapt to sea-level rise. It also offers a basis for identifying the distribution of related social outcomes across populations exposed to sea-level rise or sea-level rise policies.

  2. Demographic responses to sea level rise in California

    SciTech Connect

    Constable, A. |; Van Arsdol, M.D. Jr.; Sherman, D.J.; Wang, J.; McMullin-Messier, P.A.; Rollin, L.

    1996-12-31

    Human consequences of sea level rise in California coastal counties reflect increasing population densities. Populations of coastal counties potentially affected by sea level rise are projected to increase from 26.2 million persons in 1990 to 63.3 million persons in 2040. Urbanization dominates Los Angeles and the South Coast and San Francisco Bay and Delta regions. California shoreline populations subject to potential disruption impacts of sea level rise are increasing rapidly. Enhanced risk zones for sea level rise are specified for the Oxnard Plain of Ventura County on the south coast of California. Four separate sea level rise scenarios are considered: (1) low (sea level rise only); (2) moderate (adding erosion); (3) high (adding erosion and storm surges); and (4) a maximum case, a 3 m enhanced risk zone. Population impacts are outlined for the 3 m zone. More serious impacts from storm surges are expected than from sea level rise and erosion. Stakeholders who support or oppose policies which may expose populations to sea level rise include energy, commercial, financial, industrial, public agency, private interest and governmental organizations. These organizations respond to extreme events from differing positions. Vested interests determine the degree of mitigation employed by stakeholders to defer impacts of sea level rise.

  3. Projections of Rapidly Rising Temperatures over Africa Under Low Mitigation

    NASA Technical Reports Server (NTRS)

    Engelbrecht, Francois; Adegoke, Jimmy; Bopape, Mary-Jane; Naidoo, Mogesh; Garland, Rebecca; Thatcher, Marcus; McGregor, John; Katzfe, Jack; Werner, Micha; Ichoku, Charles; Gatebe, Charles

    2015-01-01

    An analysis of observed trends in African annual-average near-surface temperatures over the last five decades reveals drastic increases, particularly over parts of the subtropics and central tropical Africa. Over these regions, temperatures have been rising at more than twice the global rate of temperature increase. An ensemble of high-resolution downscalings, obtained using a single regional climate model forced with the sea-surface temperatures and sea-ice fields of an ensemble of global circulation model (GCM) simulations, is shown to realistically represent the relatively strong temperature increases observed in subtropical southern and northern Africa. The amplitudes of warming are generally underestimated, however. Further warming is projected to occur during the 21st century, with plausible increases of 4-6 C over the subtropics and 3-5 C over the tropics by the end of the century relative to present-day climate under the A2 (a low mitigation) scenario of the Special Report on Emission Scenarios. High impact climate events such as heat-wave days and high fire-danger days are consistently projected to increase drastically in their frequency of occurrence. General decreases in soil-moisture availability are projected, even for regions where increases in rainfall are plausible, due to enhanced levels of evaporation. The regional downscalings presented here, and recent GCM projections obtained for Africa, indicate that African annual-averaged temperatures may plausibly rise at about 1.5 times the global rate of temperature increase in the subtropics, and at a somewhat lower rate in the tropics. These projected increases although drastic, may be conservative given the model underestimations of observed temperature trends. The relatively strong rate of warming over Africa, in combination with the associated increases in extreme temperature events, may be key factors to consider when interpreting the suitability of global mitigation targets in terms of African

  4. 'Stutter timing' for charge decay time measurement

    NASA Astrophysics Data System (ADS)

    Chubb, John; Harbour, John; Pavey, Ian

    2011-06-01

    The paper describes the approach of 'stutter timing' that has been developed to improve the accuracy of measuring charge decay times in the presence of noise in compact and portable charge decay test instrumentation. The approach involves starting and stopping the timing clock as the noisy signal rises above and falls below the target threshold voltage level.

  5. NSF's solar-terrestrial research program and RISE. [RISE (Radiative Inputs of the Sun to Earth)

    SciTech Connect

    Schatten, K.H.

    1992-01-01

    SunRISE has become a top priority proposed initiative for solar terrestrial science at NSF. NSF's priorities include People, Education, Infrastructure, and Competitiveness in Science. Within NSF's Atmospheric Division, the Solar Terrestrial (ST) Program considers the Sun as the principle driver of dynamic phenomena in the atmospheric and geospace environments. The ST [open quotes]Core[close quotes] program will place increased emphasis on the nature of solar variability and the resultant terrestrial responses. Solar variability, emphasized dramatically by flares is not well understood, particularly below the atmosphere. Yet in all its forms, outstanding problems exist from the base of the convection zone, through the photosphere, chromosphere, and corona, and into the solar wind, where interactions with the Earth system occur. Areas of increased emphasis will be to answer the following questions. How does solar variability manifest itself in terrestrial atmospheric effects What is the nature of solar activity and how does it change in its transit from deep within the Sun to the Earth How does the Sun's variable radiative emission, flares, and corpuscular radiation affect the Earth's atmosphere The impact the Sun has upon the Earth's climate through its radiative drivers is the focus for the new initiative [open quotes]SunRISE[close quotes] (Radiative Inputs of the Sun to Earth). At present, there are large uncertainties in the contribution of solar irradiance variations to global change. Properly subtracting out, the contribution of solar variability from the climate record is critical for determining human-induced changes during the present epoch.

  6. Rise, stagnation, and rise of Danish women’s life expectancy

    PubMed Central

    Lindahl-Jacobsen, Rune; Rau, Roland; Jeune, Bernard; Canudas-Romo, Vladimir; Lenart, Adam; Christensen, Kaare; Vaupel, James W.

    2016-01-01

    Health conditions change from year to year, with a general tendency in many countries for improvement. These conditions also change from one birth cohort to another: some generations suffer more adverse events in childhood, smoke more heavily, eat poorer diets, etc., than generations born earlier or later. Because it is difficult to disentangle period effects from cohort effects, demographers, epidemiologists, actuaries, and other population scientists often disagree about cohort effects’ relative importance. In particular, some advocate forecasts of life expectancy based on period trends; others favor forecasts that hinge on cohort differences. We use a combination of age decomposition and exchange of survival probabilities between countries to study the remarkable recent history of female life expectancy in Denmark, a saga of rising, stagnating, and now again rising lifespans. The gap between female life expectancy in Denmark vs. Sweden grew to 3.5 y in the period 1975–2000. When we assumed that Danish women born 1915–1945 had the same survival probabilities as Swedish women, the gap remained small and roughly constant. Hence, the lower Danish life expectancy is caused by these cohorts and is not attributable to period effects. PMID:27035998

  7. Rescuing Education: The Rise of Experiential Learning

    ERIC Educational Resources Information Center

    McKenzie, Malcolm

    2013-01-01

    The term "experiential education" can be--and has been--applied to a wide range of educational programming. Malcolm McKenzie's working definition of experiential education is this: it promotes learning through direct experience, often outside the classroom, at times not directly related to academic courses, frequently not graded,…

  8. Student Stress Is Rising, Especially among Women.

    ERIC Educational Resources Information Center

    Reisberg, Leo

    2000-01-01

    Reports findings of a 1999 survey of 261,217 college freshmen at 462 two-year and four-year institutions concerning lifestyle and stress. Finds increasing numbers of students, especially women, report feeling overwhelmed and under stress. Also reports declines in drinking and smoking, more students planning to work full-time, more students…

  9. Is School Bullying Really on the Rise?

    ERIC Educational Resources Information Center

    Rigby, Ken; Smith, Peter K.

    2011-01-01

    Whether bullying in schools is increasing, as is widely believed, was investigated drawing upon empirical studies undertaken in a wide range of countries in which findings had been published describing its prevalence at different points in time between 1990 and 2009. Results do not support the view that reported bullying in general has increased…

  10. The Rise and Fall of Type Ia Supernova Light Curves in the SDSS-II Supernova Survey

    SciTech Connect

    Hayden, Brian T.; Garnavich, Peter M.; Kessler, Richard; Frieman, Joshua A.; Jha, Saurabh W.; Bassett, Bruce; Cinabro, David; Dilday, Benjamin; Kasen, Daniel; Marriner, John; Nichol, Robert C.; /Portsmouth U., ICG /Baltimore, Space Telescope Sci. /Johns Hopkins U.

    2010-01-01

    We analyze the rise and fall times of Type Ia supernova (SN Ia) light curves discovered by the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. From a set of 391 light curves k-corrected to the rest-frame B and V bands, we find a smaller dispersion in the rising portion of the light curve compared to the decline. This is in qualitative agreement with computer models which predict that variations in radioactive nickel yield have less impact on the rise than on the spread of the decline rates. The differences we find in the rise and fall properties suggest that a single 'stretch' correction to the light curve phase does not properly model the range of SN Ia light curve shapes. We select a subset of 105 light curves well observed in both rise and fall portions of the light curves and develop a '2-stretch' fit algorithm which estimates the rise and fall times independently. We find the average time from explosion to B-band peak brightness is 17.38 {+-} 0.17 days, but with a spread of rise times which range from 13 days to 23 days. Our average rise time is shorter than the 19.5 days found in previous studies; this reflects both the different light curve template used and the application of the 2-stretch algorithm. The SDSS-II supernova set and the local SNe Ia with well-observed early light curves show no significant differences in their average rise-time properties. We find that slow-declining events tend to have fast rise times, but that the distribution of rise minus fall time is broad and single peaked. This distribution is in contrast to the bimodality in this parameter that was first suggested by Strovink (2007) from an analysis of a small set of local SNe Ia. We divide the SDSS-II sample in half based on the rise minus fall value, t{sub r} - t{sub f} {approx}< 2 days and t{sub r} - t{sub f} > 2 days, to search for differences in their host galaxy properties and Hubble residuals; we find no difference in host galaxy properties or Hubble residuals in our

  11. High tides and rising seas: potential effects on estuarine waterbirds

    USGS Publications Warehouse

    Erwin, R.M.; Sanders, G.M.; Prosser, D.J.; Cahoon, D.R.; Greenberg, Russell; Maldonado, Jesus; Droege, Sam; McDonald, M.V.

    2006-01-01

    Coastal waterbirds are vulnerable to water-level changes especially under predictions of accelerating sea-level rise and increased storm frequency in the next century. Tidal and wind-driven fluctuations in water levels affecting marshes, their invertebrate communities, and their dependent waterbirds are manifested in daily, monthly, seasonal, annual, and supra-annual (e.g., decadal or 18.6-yr) periodicities. Superimposed on these cyclic patterns is a long-term (50?80 yr) increase in relative sea-level rise that varies from about 2?4 + mm/yr along the Atlantic coastline. At five study sites selected on marsh islands from Cape Cod, Massachusetts to coastal Virginia, we monitored marsh elevation changes and flooding, tide variations over time, and waterbird use. We found from longterm marsh core data that marsh elevations at three of five sites may not be sufficient to maintain pace with current sea-level rise. Results of the short-term (3?4 yr) measures using surface elevation tables suggest a more dramatic difference, with marsh elevation change at four of five sites falling below relative sea-level rise. In addition, we have found a significant increase (in three of four cases) in the rate of surface marsh flooding in New Jersey and Virginia over the past 70?80 yr during May?July when waterbirds are nesting on or near the marsh surface. Short-term, immediate effects of flooding will jeopardize annual fecundity of many species of concern to federal and state agencies, most notably American Black Duck (Anas rubripes), Nelson?s Sharp-tailed Sparrow (Ammodramus nelsoni), Saltmarsh Sharp-tailed Sparrow (A. caudacutus), Seaside Sparrow (A. maritima), Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens), Black Rail (Laterallus jamaicensis), Forster?s Tern (Sterna forsteri), Gull-billed Tern (S. nilotica), Black Skimmer (Rynchops niger), and American Oystercatcher (Haemotopus palliatus). Forster?s Terns are probably most at risk given the large proportion of their

  12. The rise of blogs in nursing practice.

    PubMed

    Watson, Joni

    2012-04-01

    The number of blogs and related online activities continues to grow exponentially each year. Patients increasingly are turning to the Internet for personalized, timely, and relevant health information; blogs remain a large source of that information. Nurses and other healthcare professionals can harness the informational, educational, networking, and supportive power of blogs, as well, and should understand how to access and use blogs for professional use.

  13. Rising levels of atmospheric oxygen and evolution of Nrf2

    PubMed Central

    Gacesa, Ranko; Dunlap, Walter C.; Barlow, David J.; Laskowski, Roman A.; Long, Paul F.

    2016-01-01

    In mammals, the master transcription regulator of antioxidant defences is provided by the Nrf2 protein. Phylogenetic analyses of Nrf2 sequences are used here to derive a molecular clock that manifests persuasive evidence that Nrf2 orthologues emerged, and then diverged, at two time points that correlate with well-established geochemical and palaeobiological chronologies during progression of the ‘Great Oxygenation Event’. We demonstrate that orthologues of Nrf2 first appeared in fungi around 1.5 Ga during the Paleoproterozoic when photosynthetic oxygen was being absorbed into the oceans. A subsequent significant divergence in Nrf2 is seen during the split between fungi and the Metazoa approximately 1.0–1.2 Ga, at a time when oceanic ventilation released free oxygen to the atmosphere, but with most being absorbed by methane oxidation and oxidative weathering of land surfaces until approximately 800 Ma. Atmospheric oxygen levels thereafter accumulated giving rise to metazoan success known as the Cambrian explosion commencing at ~541 Ma. Atmospheric O2 levels then rose in the mid Paleozoic (359–252 Ma), and Nrf2 diverged once again at the division between mammals and non-mammalian vertebrates during the Permian-Triassic boundary (~252 Ma). Understanding Nrf2 evolution as an effective antioxidant response may have repercussions for improved human health. PMID:27297177

  14. Bangladesh to prepare for rise in gas demand

    SciTech Connect

    Not Available

    1992-06-01

    Bangladesh is moving to expand its natural gas infrastructure in response to rising domestic demand. This paper reports that Bangladesh natural gas demand is expected to rise to 700-850 MMcfd in the next few years from the current level of about 500 MMcfd, the Prime Minister Khaleda Zia.

  15. High-Rise Housing for Low-Income Families.

    ERIC Educational Resources Information Center

    Fuerst, J. S.; Petty, Roy

    1991-01-01

    Discusses successes and failures of subsidized housing in urban areas and the relationship between architectural environment and quality of life, particularly as regards high-rise buildings. Given that some high-rise projects are successful, most should be maintained because of the scarcity of low-income housing. (DM)

  16. Reliability and Validity of the Standing Heel-Rise Test

    ERIC Educational Resources Information Center

    Yocum, Allison; McCoy, Sarah Westcott; Bjornson, Kristie F.; Mullens, Pamela; Burton, Gay Naganuma

    2010-01-01

    A standardized protocol for a pediatric heel-rise test was developed and reliability and validity are reported. Fifty-seven children developing typically (CDT) and 34 children with plantar flexion weakness performed three tests: unilateral heel rise, vertical jump, and force measurement using handheld dynamometry. Intraclass correlation…

  17. The New Woman in "The Sun Also Rises"

    ERIC Educational Resources Information Center

    Yu, Xiaoping

    2010-01-01

    Hemingway is a famous American writer and a spokesman of the Lost Generation. His life attitude of the characters in the novels influenced the whole world. His first masterpiece "The Sun Also Rises" contributes a lot to the rise of feminism and make the world began to be familiar with a term: The New Woman through the portrayal of Brett.…

  18. The Rise and Fall of the Neo-Liberal University

    ERIC Educational Resources Information Center

    Davies, Bronwyn; Gottsche, Michael; Bansel, Peter

    2006-01-01

    The rise of neo-liberal universities over the last 15-20 years has been characterised as an inevitable effect both of globalisation and the associated dominance of capital. In this article we will analyse that rise, seeking to understand how it has come about and its impact on intellectual work. In the final pages of the article we turn towards…

  19. RISE Evaluation and Development System: Student Learning Objectives Handbook

    ERIC Educational Resources Information Center

    Indiana Department of Education, 2016

    2016-01-01

    With the help of teachers and leaders throughout the state, the Indiana Department of Education has developed an optional model teacher evaluation system named RISE. Whether corporations choose to adopt RISE or a model of their own, the department's goal is to assist corporations in developing or adopting models that both comply with IC 20-28-11.5…

  20. 40 CFR Appendix Vi to Part 266 - Stack Plume Rise

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise Flow rate (m3/s) Exhaust Temperature...

  1. 40 CFR Appendix Vi to Part 266 - Stack Plume Rise

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise Flow rate (m3/s) Exhaust Temperature...

  2. 40 CFR Appendix Vi to Part 266 - Stack Plume Rise

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise Flow rate (m3/s) Exhaust Temperature...

  3. 40 CFR Appendix Vi to Part 266 - Stack Plume Rise

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise Flow rate (m3/s) Exhaust Temperature...

  4. 40 CFR Appendix Vi to Part 266 - Stack Plume Rise

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise Flow rate (m3/s) Exhaust Temperature...

  5. The Rise of Conservatism since World War II.

    ERIC Educational Resources Information Center

    Carter, Dan T.

    2003-01-01

    Discusses the rise of the conservatism movement in the United States since World War II. States that laissez-faire capitalism and the rise of communism contributed to the popularity of conservatism in the United States. Focuses on the role of U.S. Presidents, such as Richard Nixon and Ronald Reagan. (CMK)

  6. Estuaries May Face Increased Parasitism as Sea Levels Rise

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-12-01

    Invertebrates in estuaries could be at a greater risk of parasitism as climate change causes sea levels to rise. A new paper published 8 December in Proceedings of the National Academy of Sciences of the United States of America (doi:10.1073/pnas.1416747111) describes how rapid sea level rise in the Holocene affected the population of parasitic flatworms called trematodes.

  7. Cenozoic seismic stratigraphy of the SW Bermuda Rise

    SciTech Connect

    Mountain, G.S.; Driscoll, N.W.; Miller, K.G.

    1985-01-01

    The seismic Horizon A-Complex (Tucholke, 1979) readily explains reflector patterns observed along the western third of the Bermuda Rise; farther east, basement is much more rugged and gravity flows shed from local topographic highs complicate the stratigraphy. Distal turbidites on the southwestern Bermuda Rise onlap reflector A* from the west, suggesting early Paleocene mass wasting of the North American margin. Locally erosive bottom currents cut into the middle Eocene section of the SW Bermuda Rise; these northward flowing currents preceded those that formed reflector Au along the North American margin near the Eocene-Oligocene boundary. Southward flowing currents swift enough to erode the sea floor and to form reflector Au did not reach as far east as the SW Bermuda Rise. Instead, the main effect of these Au currents was to pirate sediment into contour-following geostrophic flows along the North American margin and to deprive the deep basin and the Bermuda Rise of sediment transported down-slope. Consequently, post-Eocene sediments away from the margin are fine-grained muds. Deposition of these muds on the SW Bermuda Rise was controlled by northward flowing bottom currents. The modern Hatteras Abyssal Plain developed in the late Neogene as turbidites once again onlapped the SW Bermuda Rise. Today, these deposits extend farthest east in fracture zone valleys and in the swales between sediment waves. Northward flowing currents continue at present to affect sediment distribution patterns along the western edge of the Bermuda Rise.

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

    PubMed

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

    2010-08-19

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

  9. El Niño and a record CO2 rise

    NASA Astrophysics Data System (ADS)

    Betts, Richard A.; Jones, Chris D.; Knight, Jeff R.; Keeling, Ralph F.; Kennedy, John J.

    2016-09-01

    The recent El Niño event has elevated the rise in CO2 concentration this year. Here, using emissions, sea surface temperature data and a climate model, we forecast that the CO2 concentration at Mauna Loa will for the first time remain above 400 ppm all year, and hence for our lifetimes.

  10. Small Impact Crater Clusters in High Resolution HiRISE Images

    NASA Astrophysics Data System (ADS)

    Ivanov, B. A.; Melosh, H. J.; McEwen, A. S.; HiRISE Team

    2008-03-01

    The HiRISE image scale of 0.25-0.32 meters per pixel allows us for the first time to resolve details of small primary crater fields on Mars. The cluster dispersion is used to estimate strength and density of meteoroids.

  11. The Formation of the Rising Generation under the Conditions of Social Differentiation in Russia

    ERIC Educational Resources Information Center

    Shabunova, A.

    2008-01-01

    The transformations in Russian society that took place in the late twentieth century and early twenty-first century led to a rapid rise in social and economic differentiation. According to official data, the income gap between the 10 percent most-well-off and the 10 percent least-well-off families (the capital coefficient) rose to 14.8 times in…

  12. Application of a rising plate meter to estimate forage yield on dairy farms in Pennsylvania

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurately assessing pasture forage yield is necessary for producers who want to budget feed expenses and make informed pasture management decisions. Clipping and weighing forage from a known area is a direct method to measure pasture forage yield, however it is time consuming. The rising plate mete...

  13. Mars reconnaissance orbiter's high resolution imaging science experiment (HiRISE)

    USGS Publications Warehouse

    McEwen, A.S.; Eliason, E.M.; Bergstrom, J.W.; Bridges, N.T.; Hansen, C.J.; Delamere, W.A.; Grant, J. A.; Gulick, V.C.; Herkenhoff, K. E.; Keszthelyi, L.; Kirk, R.L.; Mellon, M.T.; Squyres, S. W.; Thomas, N.; Weitz, C.M.

    2007-01-01

    The HiRISE camera features a 0.5 m diameter primary mirror, 12 m effective focal length, and a focal plane system that can acquire images containing up to 28 Gb (gigabits) of data in as little as 6 seconds. HiRISE will provide detailed images (0.25 to 1.3 m/pixel) covering ???1% of the Martian surface during the 2-year Primary Science Phase (PSP) beginning November 2006. Most images will include color data covering 20% of the potential field of view. A top priority is to acquire ???1000 stereo pairs and apply precision geometric corrections to enable topographic measurements to better than 25 cm vertical precision. We expect to return more than 12 Tb of HiRISE data during the 2-year PSP, and use pixel binning, conversion from 14 to 8 bit values, and a lossless compression system to increase coverage. HiRISE images are acquired via 14 CCD detectors, each with 2 output channels, and with multiple choices for pixel binning and number of Time Delay and Integration lines. HiRISE will support Mars exploration by locating and characterizing past, present, and future landing sites, unsuccessful landing sites, and past and potentially future rover traverses. We will investigate cratering, volcanism, tectonism, hydrology, sedimentary processes, stratigraphy, aeolian processes, mass wasting, landscape evolution, seasonal processes, climate change, spectrophotometry, glacial and periglacial processes, polar geology, and regolith properties. An Internet Web site (HiWeb) will enable anyone in the world to suggest HiRISE targets on Mars and to easily locate, view, and download HiRISE data products. Copyright 2007 by the American Geophysical Union.

  14. Rise in landing-related skydiving fatalities.

    PubMed

    Hart, Christian L; Griffith, James D

    2003-10-01

    The purpose was to assess whether adoption of potentially dangerous skydiving gear and skydiving practices has led to an increase in fatalities. Beginning in the early 1990s, civilian skydivers began to utilize high performance parachutes that fly much faster and are much more responsive than older style parachutes. Also, skydivers began to fly these parachutes in a more aggressive manner. An analysis of data from the 507 skydiving fatalities in the USA between 1986 and 2001 indicated that this shift toward high performance parachutes and aggressive flying techniques was temporally associated with an increase in parachute-landing deaths. During the same time period, the total number of fatalities remained fairly stable.

  15. Preparation of an exponentially rising optical pulse for efficient excitation of single atoms in free space

    NASA Astrophysics Data System (ADS)

    Dao, Hoang Lan; Aljunid, Syed Abdullah; Maslennikov, Gleb; Kurtsiefer, Christian

    2012-08-01

    We report on a simple method to prepare optical pulses with exponentially rising envelope on the time scale of a few ns. The scheme is based on the exponential transfer function of a fast transistor, which generates an exponentially rising envelope that is transferred first on a radio frequency carrier, and then on a coherent cw laser beam with an electro-optical phase modulator. The temporally shaped sideband is then extracted with an optical resonator and can be used to efficiently excite a single 87Rb atom.

  16. New analytical approximations for the liquid rise in a capillary tube

    NASA Astrophysics Data System (ADS)

    González-Santander, J. L.; Martín, G.

    2015-04-01

    We present the ordinary differential equation (ODE) that governs the motion of a liquid rising in a capillary tube in such a way that we can easily derive the principal analytical approximations given in the literature. From this presentation, the numerical solution of the liquid rise over time could be computed very quickly and easily. Furthermore, we derive other analytical approximations not given in the literature, providing a mathematical justification for the cases in which such approximations are good. Some of the approximations found fit the experimental data better than the analytical approximations given in the literature.

  17. Chemostratigraphy at DSDP Sites 386 (Bermuda Rise) and 144 (Demerara Rise), Implications for Euxinic Conditions During OAE-2

    NASA Astrophysics Data System (ADS)

    Horst, P. A.; Maurrasse, F. J.; Sinninghe-Damsté, J. S.; Sandler, A.

    2008-05-01

    Chemostratigraphic studies of DSDP Site 386 on the Bermuda Rise and Site 144 on the Demerara Rise indicate that euxinic conditions developed at these deep-water sites during the time interval that corresponds to Oceanic Anoxic Event 2 (OAE 2). The data show a large increase in Fe/Al ratios, and dispersed pyrite aggregates (Site 386 Core 43, Section 3). Such findings at these deep oceanic sites are compatible with earlier studies showing that sediments in euxinic settings display increases in Fe/Al ratios due to the scavenging of dissolved Fe, and is also in agreement with previous Pr/Ph ratio of <1 (Simoneit, 1979). This study further shows that OM, previously believed to show bimodal distribution, which was used to argue in support of turbidity currents at Site 386 as transport mechanism for some of the OM, is predominantly derived from marine phytoplankton and cyanobacteria showing low thermal stress, supporting in situ derivation. Elemental analyses at Site 386 also show that relatively high Sr/CaO ratios are present before and after OAE 2, indicating an increased contribution of biogenic carbonates, but not during the C/T boundary event. When Cr is plotted against Al2O3 in conjunction with a solid line representing the Cr/Al2O3 ratio in average shale, half of the samples fall above and half fall below this line. The values that plot above this line are all from Cores 47, 44, 43, and 42, which contain higher TOC. Their strong Cr enrichment with respect to the average shale can be indicative of an algal source of the OM, as this biota preferentially concentrates Cr. Competitive exclusion due to dominance of opportunistic prokaryotic blooms in combination with oxygen depletion can be invoked to explain the conditions that developed and were unfavorable to most other organisms throughout the water column during OAE 2. Sediments from DSDP Site 144 also reveal increased molecular fossils indicative of green sulfur bacteria, which are further characteristic of euxinic

  18. Volcanic Outgassing and the Rise of Atmospheric O2

    NASA Astrophysics Data System (ADS)

    Kasting, J. F.

    2012-12-01

    The release of reduced volcanic gases played a major role in determining atmospheric composition and redox state during the Earth's Archean era. Along with anerobic iron oxidation during deposition of banded iron-formations (BIFs), volcanic outgassing was one of two major sources of reductants, typically monitored as H2 equivalents, to the early atmosphere. These H2 sources were balanced by sinks of reductants, including escape of hydrogen to space and burial of organic matter and pyrite. The sinks for H2 can alternatively be thought of as sources for O2, following the stoichiometry: 2 H2 + O2 <--> 2 H2O. During the Archean, H2 sources were large enough to balance burial of organic matter and pyrite and still allow lots of hydrogen to escape. Sometime close to 2.4 Ga, the redox balance shifted: Either the H2 sources became smaller, or the H2 sinks became larger. The result was that O2 began to accumulate in the atmosphere for the first time, even though it was being produced by cyanobacteria well before this. This allowed a new O2 sink (H2 source) to become operative, namely, oxidative weathering of the land surface and seafloor. On the modern Earth, the redox budget is largely a balance between burial of organic matter and pyrite and oxidative weathering on land. What caused the system to shift to the oxidized state at 2.4 Ga remains a matter of debate. A secular decrease in volcanic outgassing rates alone cannot do this, as organic carbon burial is (loosely) tied to outgassing by the carbon isotope record. Roughly 15-20% of CO2 entering the combined atmosphere-ocean system appears to have been buried as organic carbon; hence, more volcanic outgassing implies more organic carbon burian (and, hence, more O2 production), if everything else stays the same. Other factors were not the same, however. Progressive growth of the continents may have helped O2 to rise, both by changing the ratio of submarine to subaerial outgassing and by facilitating greater recycling of

  19. Method for Assessing Impacts of Global Sea Level Rise on Navigation Gate Operations

    NASA Astrophysics Data System (ADS)

    Obrien, P. S.; White, K. D.; Friedman, D.

    2015-12-01

    Coastal navigation infrastructure may be highly vulnerable to changing climate, including increasing sea levels and altered frequency and intensity of coastal storms. Future gate operations impacted by global sea level rise will pose unique challenges, especially for structures 50 years and older. Our approach is to estimate future changes in gate operational frequency based on a bootstrapping method to forecast future water levels. A case study will be presented to determine future changes in frequency of operations over the next 100 years. A statistical model in the R programming language was developed to apply future sea level rise projections using the three sea level rise scenarios prescribed by USACE Engineer Regulation ER 1100-2-8162. Information derived from the case study will help forecast changes in operational costs caused by increased gate operations and inform timing of decisions on adaptation measures.

  20. Comment [on “Sea level rise shown to drive coastal erosion”

    USGS Publications Warehouse

    Sallenger,, Asbury H.; Morton, Robert; Fletcher, Charles; Thieler, E. Robert; Howd, Peter

    2000-01-01

    In a recent article (Eos, Trans., AGU, February 8, 2000, p.55), Leatherman et al. [2000] state that they have confirmed an association between sea-level rise and coastal erosion. Applying their results to the New Jersey, Delaware, and Maryland coasts and using a projected sea-level rise, the authors predict that by 2050 the shoreline will recede 60 m, about two times the average beach width. However, Leatherman et al. [2000] have not convincingly quantified a relationship between sea-level rise and shoreline erosion.We do not agree with their rationale for subsetting their data, and they have not considered other explanations for a background erosion along the U.S. east coast. Furthermore, their future projections are not supported by their analyses.

  1. Radiometric Calibration of Mars HiRISE High Resolution Imagery Based on Fpga

    NASA Astrophysics Data System (ADS)

    Hou, Yifan; Geng, Xun; Xing, Shuai; Tang, Yonghe; Xu, Qing

    2016-06-01

    Due to the large data amount of HiRISE imagery, traditional radiometric calibration method is not able to meet the fast processing requirements. To solve this problem, a radiometric calibration system of HiRISE imagery based on field program gate array (FPGA) is designed. The montage gap between two channels caused by gray inconsistency is removed through histogram matching. The calibration system is composed of FPGA and DSP, which makes full use of the parallel processing ability of FPGA and fast computation as well as flexible control characteristic of DSP. Experimental results show that the designed system consumes less hardware resources and the real-time processing ability of radiometric calibration of HiRISE imagery is improved.

  2. Models for the rise of the dinosaurs.

    PubMed

    Benton, Michael J; Forth, Jonathan; Langer, Max C

    2014-01-20

    Dinosaurs arose in the early Triassic in the aftermath of the greatest mass extinction ever and became hugely successful in the Mesozoic. Their initial diversification is a classic example of a large-scale macroevolutionary change. Diversifications at such deep-time scales can now be dissected, modelled and tested. New fossils suggest that dinosaurs originated early in the Middle Triassic, during the recovery of life from the devastating Permo-Triassic mass extinction. Improvements in stratigraphic dating and a new suite of morphometric and comparative evolutionary numerical methods now allow a forensic dissection of one of the greatest turnovers in the history of life. Such studies mark a move from the narrative to the analytical in macroevolutionary research, and they allow us to begin to answer the proposal of George Gaylord Simpson, to explore adaptive radiations using numerical methods.

  3. [The rise and fall of pathology techniques].

    PubMed

    van den Tweel, Jan G; van Diest, Paul J

    2011-01-01

    For the past 150 years the most constant factor in the pathologist's histopathological diagnostic work-up has been haematoxylin staining. This technique, in combination with later additional staining techniques, determined knowledge on a cellular level for a long time. The invention of the transmission electron microscope added an ultrastructural dimension, and for many decennia in the middle of the twentieth century this was an important diagnostic tool. Enzyme histochemistry and morphometry came next, but these techniques never really became important as they were largely overtaken by immunohistochemistry and molecular diagnostics. These, in their turn, will face competition from proteomics and other forms of genomics. It seems likely that the trusty light microscope will lose out to digital microscopy, which is developing rapidly and offers the possibility to make a diagnosis at a distance. Pathology will continue to be a specialty on the move.

  4. Rising Temperatures Reduce Global Wheat Production

    NASA Technical Reports Server (NTRS)

    Asseng, S.; Ewert, F.; Martre, P.; Rötter, R. P.; Lobell, D. B.; Cammarano, D.; Kimball, B. A.; Ottman, M. J.; Wall, G. W.; White, J. W.; Reynolds, M. P.; Alderman, P. D.; Prasad, P. V. V.; Aggarwal, P. K.; Anothai, J.; Basso, B.; Biernath, C.; Challinor, A. J.; De Sanctis, G.; Doltra, J.; Fereres, E.; Garcia-Vila, M.; Gayler, S.; Hoogenboom, G.; Hunt, L. A.; Izaurralde, R. C.; Jabloun, M.; C. D. Jones,; Kersebaum, K. C.; Koehler, A-K.; Müller, C.; Naresh Kumar, S.; Nendel, C.; O’Leary, G.; Olesen, J. E.; Palosuo, T.; Priesack, E.; Eyshi Rezaei, E.; Ruane, A. C.; Semenov, M. A.; Shcherbak, I.; Stöckle, C.; Stratonovitch, P.; Streck, T.; Supit, I.; Tao, F.; Thorburn, P. J.; Waha, K.; Wang, E.; Wallach, D.; Wolf, J.; Zhao, Z.; Zhu, Y.

    2015-01-01

    Crop models are essential tools for assessing the threat of climate change to local and global food production. Present models used to predict wheat grain yield are highly uncertain when simulating how crops respond to temperature. Here we systematically tested 30 different wheat crop models of the Agricultural Model Intercomparison and Improvement Project against field experiments in which growing season mean temperatures ranged from 15 degrees C to 32? degrees C, including experiments with artificial heating. Many models simulated yields well, but were less accurate at higher temperatures. The model ensemble median was consistently more accurate in simulating the crop temperature response than any single model, regardless of the input information used. Extrapolating the model ensemble temperature response indicates that warming is already slowing yield gains at a majority of wheat-growing locations. Global wheat production is estimated to fall by 6% for each degree C of further temperature increase and become more variable over space and time.

  5. Estimating Temperature Rise Due to Flashlamp Heating Using Irreversible Temperature Indicators

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay M.

    1999-01-01

    One of the nondestructive thermography inspection techniques uses photographic flashlamps. The flashlamps provide a short duration (about 0.005 sec) heat pulse. The short burst of energy results in a momentary rise in the surface temperature of the part. The temperature rise may be detrimental to the top layer of the part being exposed. Therefore, it is necessary to ensure the nondestructive nature of the technique. Amount of the temperature rise determines whether the flashlamp heating would be detrimental to the part. A direct method for the temperature measurement is to use of an infrared pyrometer that has much shorter response time than the flash duration. In this paper, an alternative technique is given using the irreversible temperature 'indicators. This is an indirect technique and it measures the temperature rise on the irreversible temperature indicators and computes the incident heat flux. Once the heat flux is known, the temperature rise on the part can be computed. A wedge shaped irreversible temperature indicator for measuring the heat flux is proposed. A procedure is given to use the wedge indicator.

  6. Rise of an argon bubble in liquid steel in the presence of a transverse magnetic field

    NASA Astrophysics Data System (ADS)

    Jin, K.; Kumar, P.; Vanka, S. P.; Thomas, B. G.

    2016-09-01

    The rise of gaseous bubbles in viscous liquids is a fundamental problem in fluid physics, and it is also a common phenomenon in many industrial applications such as materials processing, food processing, and fusion reactor cooling. In this work, the motion of a single argon gas bubble rising in quiescent liquid steel under an external magnetic field is studied numerically using a Volume-of-Fluid method. To mitigate spurious velocities normally generated during numerical simulation of multiphase flows with large density differences, an improved algorithm for surface tension modeling, originally proposed by Wang and Tong ["Deformation and oscillations of a single gas bubble rising in a narrow vertical tube," Int. J. Therm. Sci. 47, 221-228 (2008)] is implemented, validated and used in the present computations. The governing equations are integrated by a second-order space and time accurate numerical scheme, and implemented on multiple Graphics Processing Units with high parallel efficiency. The motion and terminal velocities of the rising bubble under different magnetic fields are compared and a reduction in rise velocity is seen in cases with the magnetic field applied. The shape deformation and the path of the bubble are discussed. An elongation of the bubble along the field direction is seen, and the physics behind these phenomena is discussed. The wake structures behind the bubble are visualized and effects of the magnetic field on the wake structures are presented. A modified drag coefficient is obtained to include the additional resistance force caused by adding a transverse magnetic field.

  7. Lava rise ridges of the Toomba basalt flow, north Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Whitehead, P. W.; Stephenson, P. J.

    1998-11-01

    Unusually long lava rises occur in the distal portion of the Toomba basalt flow, up to 120 km from the source. In the Lolworth creek region, three parallel lava rise ridges occur over a 6 km section. Two of these ridges are continuous for the entire 6 km. The ridges average 7 m in height and range from 35 m to 300 m in width. Lava inflation clefts are numerous, and lava rise pits also occur. Down flow, a single lava rise ridge, averaging 18 m high and up to 500 m wide, extends for a further 10 km. This ridge has a generally level surface with abrupt edges sloping between 45° and 90°. Accurate surveys across the ridges show that in some cases there has been some stretching of the surface, presumably prior to the formation of the prominent clefts. The ridges were formed from an initially thin flow that was inflated by a continuous layer of lava that underlay almost the entire width of each ridge, rather than by a system of lava tubes of more limited dimensions. Inflated material represents over 90% of the volume of the distal parts of the flow. Estimates of the time required to inflate the lava rise ridges range from 60 days to a year.

  8. Sea-Level Rise Impacts on Hudson River Marshes

    NASA Astrophysics Data System (ADS)

    Hooks, A.; Nitsche, F. O.

    2015-12-01

    The response of tidal marshes to increasing sea-level rise is uncertain. Tidal marshes can adapt to rising sea levels through vertical accretion and inland migration. Yet tidal marshes are vulnerable to submergence if the rate of sea-level rise exceeds the rate of accretion and if inland migration is limited by natural features or development. We studied how Piermont and Iona Island Marsh, two tidal marshes on the Hudson River, New York, would be affected by sea-level rise of 0.5m, 1m, and 1.5m by 2100. This study was based on the 2011-2012 Coastal New York LiDAR survey. Using GIS we mapped sea-level rise projections accounting for accretion rates and calculated the submerged area of the marsh. Based on the Hudson River National Estuarine Research Reserve Vegetation 2005 dataset, we studied how elevation zones based on vegetation distributions would change. To evaluate the potential for inland migration, we assessed land cover around each marsh using the National Land Cover Database 2011 Land Cover dataset and examined the slope beyond the marsh boundaries. With an accretion rate of 0.29cm/year and 0.5m of sea-level rise by 2100, Piermont Marsh would be mostly unchanged. With 1.5m of sea-level rise, 86% of Piermont Marsh would be flooded. For Iona Island Marsh with an accretion rate of 0.78cm/year, sea-level rise of 0.5m by 2100 would result in a 4% expansion while 1.5m sea-level rise would cause inundation of 17% of the marsh. The results indicate that Piermont and Iona Island Marsh may be able to survive rates of sea-level rise such as 0.5m by 2100 through vertical accretion. At rates of sea-level rise like 1.5m by 2100, vertical accretion cannot match sea-level rise, submerging parts of the marshes. High elevations and steep slopes limit Piermont and Iona Island Marsh's ability to migrate inland. Understanding the impacts of sea-level rise on Piermont and Iona Island Marsh allows for long-term planning and could motivate marsh conservation programs.

  9. Online Citizen Science with Clickworkers & MRO HiRISE E/PO

    NASA Astrophysics Data System (ADS)

    Gulick, V. C.; Deardorff, G.; Kanefsky, B.; HiRISE Science Team

    2010-12-01

    contributors. In HiRISE Clickworkers, over a dozen different geologic features have been identified on over 57,000 image tiles. A key objective of Clickworkers has been to break up work into manageable chunks so that people can contribute a few minutes at a time and their work all adds up. Our HiRISE Student Image Challenges (http://quest.nasa.gov), another online citizen science project, provide educators and students a virtual science team experience. Registered participants are given access to HiWeb, the HiRISE team’s image suggestion facility to submit their image suggestions. Once the images are returned, students browse, pan and zoom through their acquired images online and at full resolution before they are released to the public (http://marsoweb.nas.nasa.gov/HiRISE/quest/). Students fill out a report form summarizing the key results of their image analysis and with the help of a HiRISE team member write a caption for their image. The image is posted on the HiRISE image release website along with the caption, with credit to the suggesting class and school. HiWish, HiRISE’s public image suggestion website (see McEwen et al., this mtg.), provides a simpler interface for the public at large to submit HiRISE images. HiWish also provides a list of recently submitted image requests.

  10. Effects of sea level rise on deltaic coastal marshlands, Mississippi River deltaic plain

    SciTech Connect

    Ramsey, K.E.; Penland, S. ); Roberts, H.H.; Coleman, J.M. )

    1990-05-01

    Low-relief deltaic coastal plains commonly experience land loss because of the cumulative effects of natural and human-induced processes. Although it is difficult to separate the individual factors within the overall process, interplay between these factors can result in a rate of relative sea level rise greater than the natural rate of coastal-plain aggradation that causes land loss. Between 1956 and 1978, about 11,400 and 2,490 ha of marsh were lost in east Texas and Mississippi, respectively. Louisiana's loss was 18,755 ha. Relative sea level rise over the last 65 yr has averaged 0.23 cm/yr in the Gulf and as much as 1-1.5 cm/yr in the delta plain. The Environmental Protection Agency predicts the rate of sea level rise to increase over the next century. Rates of relative sea level rise for the Gulf of Mexico are expected to increase from 0.23-1.5 cm/yr to 0.6-3.7 cm/yr. The current rate of relative sea level rise and land loss in the subsiding Mississippi delta is a response that can be expected for many US coastal areas over the next century. With the predicted change, the Mississippi River delta complex will experience dramatically increased rates of land loss. Isles Dernieres will disappear by the year 2000, and Plaquemines and Terrebonne marshes will be gone between 2020 and 2080. Based on the lowest predicted sea level rise rate, by the year 2100, the delta plain could be reduced from 150.9 {times} 10{sup 3} ha to 29.8 x 10{sup 3} ha or to 4.9 {times} 10{sup 3} ha if calculations are based on the highest rate.

  11. Flooded Dark Matter and S level rise

    NASA Astrophysics Data System (ADS)

    Randall, Lisa; Scholtz, Jakub; Unwin, James

    2016-03-01

    Most dark matter models set the dark matter relic density by some interaction with Standard Model particles. Such models generally assume the existence of Standard Model particles early on, with the dark matter relic density a later consequence of those interactions. Perhaps a more compelling assumption is that dark matter is not part of the Standard Model sector and a population of dark matter too is generated at the end of inflation. This democratic assumption about initial conditions does not necessarily provide a natural value for the dark matter relic density, and furthermore superficially leads to too much entropy in the dark sector relative to ordinary matter. We address the latter issue by the late decay of heavy particles produced at early times, thereby associating the dark matter relic density with the lifetime of a long-lived state. This paper investigates what it would take for this scenario to be compatible with observations in what we call Flooded Dark Matter (FDM) models and discusses several interesting consequences. One is that dark matter can be very light and furthermore, light dark matter is in some sense the most natural scenario in FDM as it is compatible with larger couplings of the decaying particle. A related consequence is that the decay of the field with the smallest coupling and hence the longest lifetime dominates the entropy and possibly the matter content of the Universe, a principle we refer to as "Maximum Baroqueness". We also demonstrate that the dark sector should be colder than the ordinary sector, relaxing the most stringent free-streaming constraints on light dark matter candidates. We will discuss the potential implications for the core-cusp problem in a follow-up paper. The FDM framework will furthermore have interesting baryogenesis implications. One possibility is that dark matter is like the baryon asymmetry and both are simultaneously diluted by a late entropy dump. Alternatively, FDM is compatible with an elegant non

  12. The contribution of sea-level rise to flooding in large river catchments

    NASA Astrophysics Data System (ADS)

    Thiele-Eich, I.; Hopson, T. M.; Gilleland, E.; Lamarque, J.; Hu, A.; Simmer, C.

    2012-12-01

    Climate change is expected to both impact sea level rise as well as flooding. Our study focuses on the combined effect of climate change on upper catchment precipitation as well as on sea-level rise at the river mouths and the impact this will have on river flooding both at the coast and further upstream. We concentrate on the eight catchments of the Amazonas, Congo, Orinoco, Ganges/Brahmaputra/Meghna, Mississippi, St. Lawrence, Danube and Niger rivers. To assess the impact of climate change, upper catchment precipitation as well as monthly mean thermosteric sea-level rise at the river mouth outflow are taken from the four CCSM4 1° 20th Century ensemble members as well as from six CCSM4 1° ensemble members for the RCP scenarios RCP8.5, 6.0, 4.5 and 2.6. Continuous daily time series for average catchment precipitation and discharge are available for each of the catchments. To arrive at a future discharge time series, we used these observations to develop a simple statistical hydrological model which can be applied to the modelled future upper catchment precipitation values. The analysis of this surrogate discharge time series alone already yields significant changes in flood return levels as well as flood duration. Using the geometry of the river channel, the backwater effect of sea-level rise is incorporated in our analysis of both flood frequencies and magnitudes by calculating the effective additional discharge due to the increase in water level at the river mouth outflow, as well as its tapering impact upstream. By combining these effects, our results focus on the merged impact of changes in extreme precipitation with increases in river height due to sea-level rise at the river mouths. Judging from our preliminary results, the increase in effective discharge due to sea-level rise cannot be neglected when discussing late 21st century flooding in the respective river basins. In particular, we find that especially in countries with low elevation gradient, flood

  13. Preferential Nucleosome Occupancy at High Values of DNA Helical Rise

    PubMed Central

    Pedone, Francesco; Santoni, Daniele

    2012-01-01

    Nucleosomes are the basic structural units of eukaryotic chromatin and play a key role in the regulation of gene expression. Nucleosome formation depends on several factors, including properties of the sequence itself, but also physical constraints and epigenetic factors such as chromatin-remodelling enzymes. In this view, a sequence-dependent approach is able to capture a general tendency of a region to bind a histone octamer. A reference data set of positioned nucleosomes of Saccharomyces cerevisiae was used to study the role of DNA helical rise in histone–DNA interaction. Genomic sequences were transformed into arrays of helical rise values by a tetranucleotide code and then turned into profiles of mean helical rise values. These profiles resemble maps of nucleosome occupancy, suggesting that intrinsic histone–DNA interactions are linked to helical rise. The obtained results show that preferential nucleosome occupancy occurs where the mean helical rise reaches its largest values. Mean helical rise profiles obtained by using maps of positioned nucleosomes of the Drosophila melanogaster and Plasmodium falciparum genomes, as well as Homo sapiens chromosome 20 confirm that nucleosomes are mainly located where the mean helical rise reaches its largest values. PMID:22233711

  14. Rising CO2 concentrations affect settlement behaviour of larval damselfishes

    NASA Astrophysics Data System (ADS)

    Devine, B. M.; Munday, P. L.; Jones, G. P.

    2012-03-01

    Reef fish larvae actively select preferred benthic habitat, relying on olfactory, visual and acoustic cues to discriminate between microhabitats at settlement. Recent studies show exposure to elevated carbon dioxide (CO2) impairs olfactory cue recognition in larval reef fishes. However, whether this alters the behaviour of settling fish or disrupts habitat selection is unknown. Here, the effect of elevated CO2 on larval behaviour and habitat selection at settlement was tested in three species of damselfishes (family Pomacentridae) that differ in their pattern of habitat use: Pomacentrus amboinensis (a habitat generalist), Pomacentrus chrysurus (a rubble specialist) and Pomacentrus moluccensis (a live coral specialist). Settlement-stage larvae were exposed to current-day CO2 levels or CO2 concentrations that could occur by 2100 (700 and 850 ppm) based on IPCC emission scenarios. First, pair-wise choice tests were performed using a two-channel flume chamber to test olfactory discrimination between hard coral, soft coral and coral rubble habitats. The habitat selected by settling fish was then compared among treatments using a multi-choice settlement experiment conducted overnight. Finally, settlement timing between treatments was compared across two lunar cycles for one of the species, P. chrysurus. Exposure to elevated CO2 disrupted the ability of larvae to discriminate between habitat odours in olfactory trials. However, this had no effect on the habitats selected at settlement when all sensory cues were available. The timing of settlement was dramatically altered by CO2 exposure, with control fish exhibiting peak settlement around the new moon, whereas fish exposed to 850 ppm CO2 displaying highest settlement rates around the full moon. These results suggest larvae can rely on other sensory information, such as visual cues, to compensate for impaired olfactory ability when selecting settlement habitat at small spatial scales. However, rising CO2 could cause larvae

  15. A Current Source Method For t(sub q) Measurement of Fast Switching Thyristors

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.

    2006-01-01

    A current source driven circuit has been constructed to measure the turn-off time (t(sub q)) of fast-switching SiC thyristors. This circuit operates from a single power supply and a dual channel pulse generator to provide adjustment of forward current, magnitude and duration of reverse applied voltage, and rate of rise of reapplied forward voltage. Values of t(sub q) down to 100 ns can be resolved.

  16. Pulsed Electric Fields for Biological Weapons Defense

    DTIC Science & Technology

    2002-01-01

    studies of Bacillus atrophaeus (formerly Bacillus subtilis var. niger). 15. SUBJECT TERMS nanosecond high-field electric pulse, electroperturbation...sterility monitoring kit, which utilizes spores of Bacillus atrophaeus (formerly Bacillus subtilis var. niger) deposited on paper in glassine envelopes, has...report a study of the application of ultra- short high-field electric pulses (5 MV/m, 100-ns pulse width, 4-ns rise time) to Bacillus atrophaeus spores

  17. Stability of peatland carbon to rising temperatures

    SciTech Connect

    Wilson, R. M.; Hopple, A. M.; Tfaily, M. M.; Sebestyen, S. D.; Schadt, C. W.; Pfeifer-Meister, L.; Medvedeff, C.; McFarlane, K. J.; Kostka, J. E.; Kolton, M.; Kolka, R. K.; Kluber, L. A.; Keller, J. K.; Guilderson, T. P.; Griffiths, N. A.; Chanton, J. P.; Bridgham, S. D.; Hanson, P. J.

    2016-12-13

    Peatlands contain one-third of the world’s soil carbon (C), mostly in the deep permanently saturated anoxic zone (i.e., catotelm)1 where C mineralization rates may be constrained, in part, by low temperatures; yet all soil warming experiments to date have focused on the response of peatland C degradation to surface warming2, 3. If the slow decomposition of deep peat C is due to kinetic constraints, then increasing temperatures at depth should cause parallel increases in carbon dioxide (CO2) and/or methane (CH4) production rates. Increasing CH4 emissions are of particular concern because CH4 has a sustained-flux global warming potential (SGWP) 45-times greater than CO2 over a 100- year timeframe4, creating a significant positive feedback to climate warming. Using a novel whole-ecosystem scale experiment in a regression-based design we show that ecosystem scale warming of deep peat exponentially increased CH4 emissions —but not ecosystem respiration of CO2— in the first year. Multiple lines of evidence, including laboratory incubations and in situ analyses of 14C, dissolved gases, and microbial community metabolic potential, indicate that CH4 emissions increased due to surface processes and not degradation of deep C. Our results indicate that rapid changes to the large bank of deep buried C in temperate peatlands may be minimal under future climatic warming.

  18. The rise of novelty in ecosystems.

    PubMed

    Radeloff, Volker C; Williams, John W; Bateman, Brooke L; Burke, Kevin D; Carter, Sarah K; Childress, Evan S; Cromwell, Kara J; Gratton, Claudio; Hasley, Andrew O; Kraemer, Benjamin M; Latzka, Alexander W; Marin-Spiotta, Erika; Meine, Curt D; Munoz, Samuel E; Neeson, Thomas M; Pidgeon, Anna M; Rissman, Adena R; Rivera, Ricardo J; Szymanski, Laura M; Usinowicz, Jacob

    2015-12-01

    Rapid and ongoing change creates novelty in ecosystems everywhere, both when comparing contemporary systems to their historical baselines, and predicted future systems to the present. However, the level of novelty varies greatly among places. Here we propose a formal and quantifiable definition of abiotic and biotic novelty in ecosystems, map abiotic novelty globally, and discuss the implications of novelty for the science of ecology and for biodiversity conservation. We define novelty as the degree of dissimilarity of a system, measured in one or more dimensions relative to a reference baseline, usually defined as either the present or a time window in the past. In this conceptualization, novelty varies in degree, it is multidimensional, can be measured, and requires a temporal and spatial reference. This definition moves beyond prior categorical definitions of novel ecosystems, and does not include human agency, self-perpetuation, or irreversibility as criteria. Our global assessment of novelty was based on abiotic factors (temperature, precipitation, and nitrogen deposition) plus human population, and shows that there are already large areas with high novelty today relative to the early 20th century, and that there will even be more such areas by 2050. Interestingly, the places that are most novel are often not the places where absolute changes are largest; highlighting that novelty is inherently different from change. For the ecological sciences, highly novel ecosystems present new opportunities to test ecological theories, but also challenge the predictive ability of ecological models and their validation. For biodiversity conservation, increasing novelty presents some opportunities, but largely challenges. Conservation action is necessary along the entire continuum of novelty, by redoubling efforts to protect areas where novelty is low, identifying conservation opportunities where novelty is high, developing flexible yet strong regulations and policies, and

  19. The Import of the Cortisol Rise in Child Care Differs as a Function of Behavioral Inhibition

    ERIC Educational Resources Information Center

    Gunnar, Megan R.; Kryzer, Erin; Van Ryzin, Mark J.; Phillips, Deborah A.

    2011-01-01

    Children of ages 3 to 4.5 years (N = 107; 45 boys, 62 girls) were studied twice, 6 months apart, to examine whether the cortisol rise in child care at Time 1 (T1) was associated with (a) changes in anxious, vigilant behavior from T1 to Time 2 (T2) and (b) higher internalizing symptoms at T2. Controlling for measures of home environment and child…

  20. Relativistic rise measurement for heavy cosmic rays in xenon

    NASA Technical Reports Server (NTRS)

    Gregory, J. C.; Parnell, T. A.; Watts, J., Jr.

    1982-01-01

    Potential advantages of the use of the relativistic rise of energy loss in gas-filled counters for cosmic ray energy measurement have been noted by Tueller et al. (1979) and Gregory and Parnell (1979). Gregory and Parnell have reported measurements on the relativistic rise for cosmic ray iron nuclei in parallel plate ionization chambers 8.4 cm thick filled with a xenon and methane mixture. The present investigation is concerned with the observed rise and ionization signal fluctuations for a sample of elements from carbon through iron in the cosmic rays. The results are compared with a calculation of the energy deposit within the ion chamber.

  1. Coastal Impact Underestimated From Rapid Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Anderson, John; Milliken, Kristy; Wallace, Davin; Rodriguez, Antonio; Simms, Alexander

    2010-06-01

    A primary effect of global warming is accelerated sea level rise, which will eventually drown low-lying coastal areas, including some of the world's most populated cities. Predictions from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) suggest that sea level may rise by as much as 0.6 meter by 2100 [Solomon et al., 2007]. However, uncertainty remains about how projected melting of the Greenland and Antarctic ice sheets will contribute to sea level rise. Further, considerable variability is introduced to these calculations due to coastal subsidence, especially along the northern Gulf of Mexico (see http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml).

  2. The complex reality of sea-level rise in an atoll nation

    NASA Astrophysics Data System (ADS)

    Donner, S. D.

    2012-12-01

    Sea-level rise famously poses an existential threat to island nations like Kiribati, Tuvalu and the Maldives. Yet as the global mean sea-level rises, the response of any one location at any given time will depend on the natural variability in regional sea-level and other impact of local human activities on coastal processes. As with climate warming, the state of an individual shoreline or the extent of flooding on a given day is not proof of a sea-level trend, nor is a global sea-level trend a good predictor of individual flooding or erosion events. Failure to consider the effect of natural variability and local human activity on coastal processes often leads to misattribution of flooding events and even some long-term shoreline changes to global sea level rise. Moreover, unverified attribution of individual events or changes to specific islets to sea level rise can inflame or invite scepticism of the strong scientific evidence for an accelerating increase in the global sea level due to the impacts of human activity on the climate system. This is particularly important in developing nations like Kiribati, which are depending on international financial support to adapt to rising sea levels. In this presentation, I use gauge data and examples from seven years of field work in Tarawa Atoll, the densely populated capital of Kiribati, to examine the complexity of local sea level and shoreline change in one of the world's most vulnerable countries. First, I discuss how the combination of El Nino-driven variability in sea-level and the astronomical tidal cycle leads to flooding and erosion events which can be mistaken for evidence of sea-level rise. Second, I show that human modification to shorelines has redirected sediment supply, leading, in some cases, to expansion of islets despite rising sea levels. Taken together, the analysis demonstrates the challenge of attributing particular coastal events to global mean sea-level rise and the impact on decision-making. The

  3. An all-or-nothing rise in cytosolic

    PubMed

    Katoh; Kikuyama

    1997-01-01

    The peritrich ciliate Vorticella sp. exhibits cellular contraction of an all-or-nothing type in response to a mechanical stimulus. Many authors have suggested that the contraction may be controlled by the cytosolic level of Ca2+, since glycerol-extracted Vorticella contracts when Ca2+ is added to the external solution. However, no direct evidence for the increase in cytosolic [Ca2+] has yet been obtained in living Vorticella. In the present study, by injecting a fluorescent Ca2+ indicator into living Vorticella and monitoring the cytosolic [Ca2+] with a confocal microscope, we have demonstrated that a mechanical stimulus evoked an all-or-nothing rise in cytosolic [Ca2+] (Ca2+ 'spike'). The onset of the Ca2+ spike was similar in its time course to that of cellular contraction. Since the Ca2+ spike was recorded in a Ca2+-deprived solution containing 1 mmol l-1 EGTA, we concluded that release of Ca2+ from intracellular Ca2+ storage site(s) is responsible for the Ca2+ spike.

  4. Ventilation and infiltration in high-rise apartment buildings

    SciTech Connect

    Diamond, R.C.; Feustel, H.E.; Dickerhoff, D.J.

    1996-03-01

    Air flow, air leakage measurements and numerical simulations were made on a 13-story apartment building to characterize the ventilation rates for the individual apartments. Parametric simulations were performed for specific conditions, e.g., height, orientation, outside temperature and wind speed. Our analysis of the air flow simulations suggest that the ventilation to the individual units varies considerably. With the mechanical ventilation system disabled and no wind, units at the lower level of the building have adequate ventilation only on days with high temperature differences, while units on higher floors have no ventilation at all. Units facing the windward side will be over-ventilated when the building experiences wind directions between west and north. At the same time, leeward apartments did not experience any fresh air-because, in these cases, air flows enter the apartments from the corridor and exit through the exhaust shafts and the cracks in the facade. Even with the mechanical ventilation system operating, we found wide variation in the air flows to the individual apartments. In addition to the specific case presented here, these findings have more general implications for energy retrofits and health and comfort of occupants in high-rise apartment buildings.

  5. Simulations of Sea Level Rise Effects on Complex Coastal Systems

    NASA Astrophysics Data System (ADS)

    Niedoroda, A. W.; Ye, M.; Saha, B.; Donoghue, J. F.; Reed, C. W.

    2009-12-01

    It is now established that complex coastal systems with elements such as beaches, inlets, bays, and rivers adjust their morphologies according to time-varying balances in between the processes that control the exchange of sediment. Accelerated sea level rise introduces a major perturbation into the sediment-sharing systems. A modeling framework based on a new SL-PR model which is an advanced version of the aggregate-scale CST Model and the event-scale CMS-2D and CMS-Wave combination have been used to simulate the recent evolution of a portion of the Florida panhandle coast. This combination of models provides a method to evaluate coefficients in the aggregate-scale model that were previously treated as fitted parameters. That is, by carrying out simulations of a complex coastal system with runs of the event-scale model representing more than a year it is now possible to directly relate the coefficients in the large-scale SL-PR model to measureable physical parameters in the current and wave fields. This cross-scale modeling procedure has been used to simulate the shoreline evolution at the Santa Rosa Island, a long barrier which houses significant military infrastructure at the north Gulf Coast. The model has been used to simulate 137 years of measured shoreline change and to extend these to predictions of future rates of shoreline migration.

  6. Chopper system for time resolved experiments with synchrotron radiation.

    PubMed

    Cammarata, Marco; Eybert, Laurent; Ewald, Friederike; Reichenbach, Wolfgang; Wulff, Michael; Anfinrud, Philip; Schotte, Friedrich; Plech, Anton; Kong, Qingyu; Lorenc, Maciej; Lindenau, Bernd; Räbiger, Jürgen; Polachowski, Stephan

    2009-01-01

    A chopper system for time resolved pump-probe experiments with x-ray beams from a synchrotron is described. The system has three parts: a water-cooled heatload chopper, a high-speed chopper, and a millisecond shutter. The chopper system, which is installed in beamline ID09B at the European Synchrotron Radiation Facility, provides short x-ray pulses for pump-probe experiments with ultrafast lasers. The chopper system can produce x-ray pulses as short as 200 ns in a continuous beam and repeat at frequencies from 0 to 3 kHz. For bunch filling patterns of the synchrotron with pulse separations greater than 100 ns, the high-speed chopper can isolate single 100 ps x-ray pulses that are used for the highest time resolution. A new rotor in the high-speed chopper is presented with a single pulse (100 ps) and long pulse (10 micros) option. In white beam experiments, the heatload of the (noncooled) high-speed chopper is lowered by a heatload chopper, which absorbs 95% of the incoming power without affecting the pulses selected by the high speed chopper.

  7. Smoothly rising star formation histories during the reionization epoch

    NASA Astrophysics Data System (ADS)

    Finlator, Kristian; Oppenheimer, Benjamin D.; Davé, Romeel

    2011-01-01

    Cosmological hydrodynamic simulations robustly predict that high-redshift galaxy star formation histories (SFHs) are smoothly rising and vary with mass only by a scalefactor. We use our latest simulations to test whether this scenario can account for recent observations at z≥ 6 from WFC3/IR, NICMOS and IRAC. Our simulations broadly reproduce the observed ultraviolet (UV) luminosity functions and stellar mass densities and their evolution at z= 6-8, all of which are non-trivial tests of the mean SFH. In agreement with observations, simulated galaxies possess blue UV continua owing to young ages (50-150 Myr), low metallicities (0.1-0.5 Z⊙) and low dust columns [E(B-V) ≤ 0.05]. Our predicted Balmer breaks at z= 7, while significant, are ≈0.5 mag weaker than observed even after accounting for nebular line emission, suggesting observational systematic errors and/or numerical resolution limitations. Observations imply a near-unity slope in the stellar mass-star formation rate relation at all z= 6-8, confirming the prediction that SFH shapes are invariant. Dust extinction suppresses the UV luminosity density by a factor of 2-3, with suppression increasing modestly to later times owing to increasing metallicities. Current surveys detect the majority of galaxies with stellar masses exceeding 109 M⊙ and few galaxies less massive than 108.5 M⊙, implying that they probe no more than the brightest ≈30 per cent of the complete star formation and stellar mass densities at z≥ 6. Finally, we demonstrate that there is no conflict between smoothly rising SFHs and recent clustering observations. This is because momentum-driven outflows suppress star formation in low-mass haloes such that the fraction of haloes hosting observable galaxies (the ‘occupancy’) is 0.2-0.4 even though the star formation duty cycle is unity. This leads to many interesting predictions at z≥ 4, among them that (1) optically selected and UV-selected samples largely overlap; (2) few galaxies

  8. U.S. Suicide Rates Rising Faster Outside Cities

    MedlinePlus

    ... 164134.html U.S. Suicide Rates Rising Faster Outside Cities Hanging-type deaths rose more than gun-related ... large, medium and small metropolitan areas, towns and cities that weren't considered a part of a ...

  9. Angelina Jolie's Mastectomies Tied to Rise in Genetic Testing

    MedlinePlus

    ... html Angelina Jolie's Mastectomies Tied to Rise in Genetic Testing But, researchers did not find a corresponding ... Human Services. More Health News on: Breast Cancer Genetic Testing Mastectomy Recent Health News Related MedlinePlus Health ...

  10. Even Small Rise in Blood Pressure Can Harm Black Patients

    MedlinePlus

    ... html Even Small Rise in Blood Pressure Can Harm Black Patients Study shows higher early death and ... These findings provide further evidence of the potential harms in terms of increased risk of heart attacks, ...

  11. Book Review: Venus Rising: Cultural Astronomy in Southern Africa

    NASA Astrophysics Data System (ADS)

    Snedegar, K.

    2014-10-01

    Book review: Dr Peter G. Alcock's important new publication, Venus Rising: South African Astronomical Beliefs, Customs and Observations. See also articles by Alcock, P.G. and Labuscagne, L. in the next issue.

  12. ACL Tears on The Rise Among Kids, Especially Girls

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_163730.html ACL Tears on the Rise Among Kids, Especially Girls ... A common knee injury -- an anterior cruciate ligament (ACL) tear -- has steadily increased among 6- to 18- ...

  13. Shaping of the continental rise by deep geostrophic contour currents.

    PubMed

    Heezen, B C; Hollister, C D; Ruddiman, W F

    1966-04-22

    Geostrophic contour-following bottom currents involved in the deep thermohaline circulation of the world ocean appear to be the principal agents which control the shape of the continental rise and other sediment bodies.

  14. Colon Cancer on The Rise Among Gen Xers, Millennials

    MedlinePlus

    ... Colon Cancer on the Rise Among Gen Xers, Millennials And an old adversary -- the obesity epidemic -- may ... their early 50s and younger -- Gen Xers and millennials -- are experiencing significant increases in colon and rectal ...

  15. Rates of Early Deaths Rise for Whites, Drop for Blacks

    MedlinePlus

    ... gov/news/fullstory_163236.html Rates of Early Deaths Rise for Whites, Drop for Blacks Drug overdoses, ... 2017 WEDNESDAY, Jan. 25, 2017 (HealthDay News) -- Premature death rates in the United States have fallen for ...

  16. Rising Number of Kids Ill from Drinking Hand Sanitizers

    MedlinePlus

    ... html Rising Number of Kids Ill From Drinking Hand Sanitizers: CDC Some children aged 6 to 12 ... 2017 THURSDAY, March 2, 2017 (HealthDay News) -- Gel hand sanitizer dispensers are ubiquitous now in American homes ...

  17. Hospitalizations for Common Heart Rhythm Problem on the Rise

    MedlinePlus

    ... Problem on the Rise But those with atrial fibrillation are also more likely to live, study says ... with a common heart rhythm disorder called atrial fibrillation (AFib) are ending up in the hospital more ...

  18. View facing south, near Structure 515, of Transmission Line rising ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View facing south, near Structure 51-5, of Transmission Line rising out of Marias River Valley - Havre Rainbow Transmission Line, Havre City to Great Falls vicinity, Montana, Great Falls, Cascade County, MT

  19. Flat as a Pancake? Exploring Rising in Baked Goods.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 2000

    2000-01-01

    Presents an activity that can be used for acid-base chemistry, everyday chemistry, or food chemistry. Investigates the rising in baked goods. Includes both instructor information and student activity sheets. (YDS)

  20. Drilling Probes Past Carbon Cycle Perturbations on the Demerara Rise

    NASA Astrophysics Data System (ADS)

    Erbacher, Jochen; Mosher, David; Malone, Mitchell

    2004-02-01

    Ocean Drilling Program (ODP) Leg 207 recently cored sediments on the Demerara Rise at ~9°N in the tropical Atlantic and successfully recovered continuous records of the Paleocene/Eocene Thermal Maximum (PETM), the Cretaceous/Tertiary boundary (K/T), and Cretaceous Ocean Anoxic Events (OAEs). The Demerara Rise, north of Suriname and French Guyana, South America, is an ideal drilling target because expanded sections of Cretaceous- and Paleogene-age deep-sea sediments are shallowly buried and exist with good stratigraphic control in expanded sections. Furthermore, the northwestern escarpment of the Demerara Rise offered the possibility of recovering sediments along a paleo-depth transect. The paleogeographic position of the Demerara Rise lies within the core of the tropics in a location near the Equatorial Atlantic Gateway between South America and Africa, which is believed to have played an important role in controlling changes in global climate during the Cretaceous.

  1. Drilling probes past carbon cycle perturbations on the Demerara Rise

    NASA Astrophysics Data System (ADS)

    ODP Leg 207 Scientific Party; Erbacher, Jochen; Mosher, David; Malone, Mitchell

    2004-02-01

    Ocean Drilling Program (ODP) Leg 207 recently cored sediments on the Demerara Rise at ˜9°N in the tropical Atlantic and successfully recovered continuous records of the Paleocene/Eocene Thermal Maximum (PETM), the Cretaceous/Tertiary boundary (K/T), and Cretaceous Ocean Anoxic Events (OAEs). The Demerara Rise, north of Suriname and French Guyana, South America, is an ideal drilling target because expanded sections of Cretaceous- and Paleogene-age deep-sea sediments are shallowly buried and exist with good stratigraphic control in expanded sections. Furthermore, the northwestern escarpment of the Demerara Rise offered the possibility of recovering sediments along a paleo-depth transect. The paleogeographic position of the Demerara Rise lies within the core of the tropics in a location near the Equatorial Atlantic Gateway between South America and Africa, which is believed to have played an important role in controlling changes in global climate during the Cretaceous.

  2. Sea-Level Projections from the SeaRISE Initiative

    NASA Technical Reports Server (NTRS)

    Nowicki, Sophie; Bindschadler, Robert

    2011-01-01

    SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

  3. [Book review] Sea level rise: history and consequences

    USGS Publications Warehouse

    Grossman, Eric E.

    2004-01-01

    Review of: Sea level Rise: history and consequences. Bruce Douglas, Michael S. Kearney and Stephen P. Leatherman (eds), Sand Diego: Academic Press, 2001, 232 pp. plus CD-RIM, US$64.95, hardback. ISBN 0-12-221345-9.

  4. Field Monitoring of Column Shortenings in a High-Rise Building during Construction

    PubMed Central

    Choi, Se Woon; Kim, Yousok; Kim, Jong Moon; Park, Hyo Seon

    2013-01-01

    The automatic monitoring of shortenings of vertical members in high-rise buildings under construction is a challenging issue in the high-rise building construction field. In this study, a practical system for monitoring column shortening in a high-rise building under construction is presented. The proposed monitoring system comprises the following components: (1) a wireless sensing system and (2) the corresponding monitoring software. The wireless sensing system comprises the sensors and energy-efficient wireless sensing units (sensor nodes, master nodes, and repeater nodes), which automate the processes for measuring the strains of vertical members and transmitting the measured data to the remote server. The monitoring software enables construction administrators to monitor real-time data collected by the server via an Internet connection. The proposed monitoring system is applied to actual 66-floor and 72-floor high-rise buildings under construction. The system enables automatic and real-time measurements of the shortening of vertical members, which can result in more precise construction. PMID:24284768

  5. Approaches to understanding life before the rise of atmospheric oxygen

    NASA Astrophysics Data System (ADS)

    Fisher, Woodward

    2010-05-01

    The Archean fossil record is notably poor. Despite major advances in deciphering the record of life in Proterozoic successions, attempts to push this understanding back into Archean time have produced frustratingly meager results. Our approach to developing a deeper understanding of the Archean biosphere has been by interrogating the biogeochemical cycles of Fe, S, and C, and reconstructing conspicuous patterns of electron transduction in ancient marine sedimentary basins. We've been working with recently collected diamond drill cores obtained by the Agouron Drilling Project through the Transvaal Supergroup from the Griqualand West structural basin in the Northern Cape Province, South Africa. This sedimentary framework is unique because it captures and provides a view of geobiological processes operating in a wide range of paleoenvironments. Three drill cores cover the development, progradation, and ultimate demise (by drowning) of the Campbellrand carbonate platform (ca. 2590Ma-2500Ma); one captures the platform top shallow marine and intertidal paleoenvironments, the other two run through slope and basinal sections (rich in banded iron formation) deposited adjacent to the platform margin increasing in water depth (to likely more than 1 km). With geobiological data and observations from these cores we can begin to reconstruct the flow of electrons in Late Archean Earth surface environments. In this talk I will present the results of two studies aimed at constraining the interplay between Fe, C, and S. Results from this approach to understanding Archean life may provide, in an integrated fashion, insight into a time before the rise of oxygen, where the fossil record and commensurate biological understanding remain penurious

  6. The East Pacific Rise: An Active Not Passive Spreading System

    NASA Astrophysics Data System (ADS)

    Rowley, D. B.; Rowan, C. J.; Forte, A. M.; Moucha, R.; Grand, S. P.; Simmons, N. A.

    2011-12-01

    Traditional plate tectonic interpretations of mid-oceanic ridges regard spreading as an entirely passive phenomenon. From this one would assume that the oceanic ridges will move over the mantle in response to the geodynamics of the diverging plates, and do not remain fixed spatially over any protracted period of time. An analysis of the kinematics of ridge motions in the Indo-Atlantic hotspot frame of reference since 83 Ma generally supports this view, with the notable exception of the East Pacific Rise (EPR). The Pacific-Nazca/Farallon segment of the EPR north of Easter Island (27°S) is oriented essentially N-S, and has produced more than 9500km of E-W spreading in the past 80 Ma, making it the dominant ridge in the world's plate system over this interval of time. Yet despite the large amount of E-W divergence, the spreading center has maintained its longitudinal position to within <±250 km of the current ridge axis. Global mantle convective flow modeling indicates that the EPR, unlike any other extensive segment of the mid-oceanic ridge system, is underlain by an active upwelling system extending from the core-mantle boundary to the surface. We suggest that the lack of E-W motion of the EPR apparent from the kinematics is a consequence of these mantle dynamics; this ridge is thus not behaving as a passive plate boundary, but is actively and directly linked to, and controlled by, whole mantle upwelling. This observation overturns the notion that ridges are always entirely passive features of the plate system. Subduction of the northern EPR beneath western North America has thus resulted in the overriding of an active upwelling system that has contributed significantly to the evolution of Basin and Range kinematics and superimposed dynamics, including significant contributions from dynamic topography.

  7. Examining the Rise in Mexican Drug Cartel Related Violence

    DTIC Science & Technology

    2016-06-10

    Calderon administration compounded the ongoing war between the drug cartels and led to the exponential rise in cartel-related violence during the...Calderon administration compounded the ongoing war between the drug cartels and led to the exponential rise in cartel-related violence during the period...professional growth . Most importantly, I would like to thank my wife Jill and children Tommy, Emily, Justin, and Mason for their love and support this year

  8. Climate change. How fast are sea levels rising?

    PubMed

    Church, J A

    2001-10-26

    Sea levels are rising as a result of global warming, but assessing the rate of the rise is proving difficult. In his Perspective, Church highlights the report by Cabanes et al., who have reassessed observational data and find that it is closer to model estimates than previously found. However, observational data are still limited and models disagree in their regional projections. With present data and models, regional sea-level changes cannot be predicted with confidence.

  9. Adapting to Rising Sea Level: A Florida Perspective

    NASA Astrophysics Data System (ADS)

    Parkinson, Randall W.

    2009-07-01

    Global climate change and concomitant rising sea level will have a profound impact on Florida's coastal and marine systems. Sea-level rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that sea-level rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of sea-level rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising sea level and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising sea level and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher sea-level elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising sea-level.

  10. The Rising Powers and Collective Security in South East Asia

    DTIC Science & Technology

    2011-03-22

    St ra te gy R es ea rc h Pr oj ec t THE RISING POWERS AND COLLECTIVE SECURITY IN SOUTH EAST ASIA BY COLONEL MICHAEL MAHY Australian...U.S. Army War College CARLISLE BARRACKS, PENNSYLVANIA 17013 ABSTRACT AUTHOR: Colonel Michael Mahy TITLE: The Rising Powers and...Asia has proved that she can do the economics. Can she also do the politics that come with power? 1 -Shivshankar Menon, India‘s National

  11. Modeling the Rise of Fibril Magnetic Fields in Fully Convective Stars

    NASA Astrophysics Data System (ADS)

    Weber, Maria A.; Browning, Matthew K.

    2016-08-01

    Many fully convective stars exhibit a wide variety of surface magnetism, including starspots and chromospheric activity. The manner by which bundles of magnetic field traverse portions of the convection zone to emerge at the stellar surface is not especially well understood. In the solar context, some insight into this process has been gleaned by regarding the magnetism as consisting partly of idealized thin flux tubes (TFTs). Here we present the results of a large set of TFT simulations in a rotating spherical domain of convective flows representative of a 0.3 M ⊙ main-sequence star. This is the first study to investigate how individual flux tubes in such a star might rise under the combined influence of buoyancy, convection, and differential rotation. A time-dependent hydrodynamic convective flow field, taken from separate 3D simulations calculated with the anelastic equations, impacts the flux tube as it rises. Convective motions modulate the shape of the initially buoyant flux ring, promoting localized rising loops. Flux tubes in fully convective stars have a tendency to rise nearly parallel to the rotation axis. However, the presence of strong differential rotation allows some initially low-latitude flux tubes of moderate strength to develop rising loops that emerge in the near-equatorial region. Magnetic pumping suppresses the global rise of the flux tube most efficiently in the deeper interior and at lower latitudes. The results of these simulations aim to provide a link between dynamo-generated magnetic fields, fluid motions, and observations of starspots for fully convective stars.

  12. Recent contributions of glaciers and ice caps to sea level rise.

    PubMed

    Jacob, Thomas; Wahr, John; Pfeffer, W Tad; Swenson, Sean

    2012-02-08

    Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr(-1) from January 2003 to December 2010, contributing 0.41 ± 0.08 mm yr(-1) to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km(2). The GIC rate for 2003-2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr(-1) for 2003-2010, compared with 47-55 Gt yr(-1) in previously published estimates. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06 ± 0.19 mm yr(-1) to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48 ± 0.26 mm (-1), which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources.

  13. Short Lived Climate Pollutants cause a Long Lived Effect on Sea-level Rise: Analyzing climate metrics for sea-level rise

    NASA Astrophysics Data System (ADS)

    Sterner, E.; Johansson, D. J.

    2013-12-01

    Climate change depends on the increase of several different atmospheric pollutants. While long term global warming will be determined mainly by carbon dioxide, warming in the next few decades will depend to a large extent on short lived climate pollutants (SLCP). Reducing emissions of SLCPs could contribute to lower the global mean surface temperature by 0.5 °C already by 2050 (Shindell et al. 2012). Furthermore, the warming effect of one of the most potent SLCPs, black carbon (BC), may have been underestimated in the past. Bond et al. (2013) presents a new best estimate of the total BC radiative forcing (RF) of 1.1 W/m2 (90 % uncertainty bounds of 0.17 to 2.1 W/m2) since the beginning of the industrial era. BC is however never emitted alone and cooling aerosols from the same sources offset a majority of this RF. In the wake of calls for mitigation of SLCPs it is important to study other aspects of the climate effect of SLCPs. One key impact of climate change is sea-level rise (SLR). In a recent study, the effect of SLCP mitigation scenarios on SLR is examined. Hu et al (2013) find a substantial effect on SLR from mitigating SLCPs sharply, reducing SLR by 22-42% by 2100. We choose a different approach focusing on emission pulses and analyse a metric based on sea level rise so as to further enlighten the SLR consequences of SLCPs. We want in particular to understand the time dynamics of SLR impacts caused by SLCPs compared to other greenhouse gases. The most commonly used physical based metrics are GWP and GTP. We propose and evaluate an additional metric: The global sea-level rise potential (GSP). The GSP is defined as the sea level rise after a time horizon caused by an emissions pulse of a forcer to the sea level rise after a time horizon caused by an emissions pulse of a CO2. GSP is evaluated and compared to GWP and GTP using a set of climate forcers chosen to cover the whole scale of atmospheric perturbation life times (BC, CH4, N2O, CO2 and SF6). The study

  14. Seismic characteristics of outer-rise earthquakes in the different seismic coupling subduction zones

    NASA Astrophysics Data System (ADS)

    Lee, Hsin-Hua; Lin, Jing-Yi

    2013-04-01

    Characterizing the seismogenic zone of major subduction plate boundaries provides us a possible to reduce large earthquakes hazard. In the past several decades, many scientists have analyzed various geophysical methods and datasets, such as seismic and geodetic ground motion data, historical tsunami deposits, aftershock distributions, and seafloor bathymetry, trying to understand the mechanisms behind great devastating earthquakes, and to estimate the probability of a major earthquake occurrence in the future. In this study, by using the global earthquake catalog (GCMT) from January 1, 1976 to December 31, 2011. We firstly re-examines the outer-rise earthquake model proposed by the Christensen (1988) at the subduction zones suggested to have different coupling levels. The compressive stress cumulated during the subducting processes are often reflected by the occurrence of compressional outer-rise earthquakes. Thus, in the region where the compressional outer-rise earthquakes take place without any corresponding large underthrusting earthquakes, the seismic potential is usually considered to be high. We re-examined the high seismic potential areas determined by this criteria in Christensen (1988) and confirm that the large underthrusting earthquakes did really occur in the 30 years following the appearance of compressional outer-rise events, such as in Tonga region in the vicinity of 20S, a Mw 8.3 large earthquake occurred in 2006. This result represents that the outer-rise earthquake model could be an indicator for the generation of large earthquakes along subduction zones. In addition, to have a more accurate estimation for the seismic potential, we discuss the relationship between the generation of earthquakes and the change of cumulative gravitational potential energy caused by earthquakes (ΔGPE) over time. Our result shows an acceleration of ΔGPE before large earthquakes. Our result also shows that the extensional outer-rise events for strong seismic coupling

  15. Sea-level rise risks to coastal cities: what are the limits to adaptation?

    NASA Astrophysics Data System (ADS)

    Nicholls, R. J.; Reeder, T.; Brown, S.; Haigh, I. D.

    2015-12-01

    Understanding the consequence of sea-level rise for coastal cities has long lead times and huge political implications. Civilisation has emerged and developed during a period of several thousand years during which in geological terms sea level has been unusually stable. We have now moved out of this period raising important challenges for the future. In 2005 there were 136 coastal cities with a population exceeding one million people and a collective population of 400 million people. All these cities are threatened by flooding from the sea to varying degrees and these risks are increasing due to growing exposure (people and assets), rising sea levels due to climate change, and in some cities, significant coastal subsidence due to human agency (drainage and groundwater withdrawals from susceptible soils). City abandonment due to sea-level rise is widely discussed in the media, but most of the discussion is speculative. The limits to adaptation and abandonment of cities are not predictable in a formal sense - while the rise in mean sea level raises the likelihood of a catastrophic flood, extreme events are what cause damage and trigger a response, be it abandonment or a defence upgrade. Several types of potential adaptation limits can be recognised: (1) physical/engineering limits; (2) economic/financial limits; and (3) socio-political limits. The latter two types of limits are much less understood, and yet issues such as loss of confidence rather than a simple engineering failure may be instrumental in the future of a coastal city. There are few studies which quantify the sea-level rise threshold at which cities will be challenged, especially for large rises exceeding a metre or more. Exceptions include London and the Thames Estuary and the Amsterdam and Rotterdam (the Netherlands) where adaptation to a rise of sea level of up to 4 m or more appears feasible. This lack of knowledge on sea-level rise thresholds for coastal cities is of concern, and similar

  16. Stress-induced rise in body temperature is repeatable in free-ranging Eastern chipmunks (Tamias striatus).

    PubMed

    Careau, Vincent; Réale, Denis; Garant, Dany; Speakman, John R; Humphries, Murray M

    2012-04-01

    In response to handling or other acute stressors, most mammals, including humans, experience a temporary rise in body temperature (T(b)). Although this stress-induced rise in T(b) has been extensively studied on model organisms under controlled environments, individual variation in this interesting phenomenon has not been examined in the field. We investigated the stress-induced rise in T(b) in free-ranging eastern chipmunks (Tamias striatus) to determine first if it is repeatable. We predicted that the stress-induced rise in T(b) should be positively correlated to factors affecting heat production and heat dissipation, including ambient temperature (T(a)), body mass (M(b)), and field metabolic rate (FMR). Over two summers, we recorded both T(b) within the first minute of handling time (T(b1)) and after 5 min of handling time (T(b5)) 294 times on 140 individuals. The mean ∆T(b) (T(b5) - T(b1)) during this short interval was 0.30 ± 0.02°C, confirming that the stress-induced rise in T(b) occurs in chipmunks. Consistent differences among individuals accounted for 40% of the total variation in ∆T(b) (i.e. the stress-induced rise in T(b) is significantly repeatable). We also found that the stress-induced rise in T(b) was positively correlated to T(a), M(b), and mass-adjusted FMR. These results confirm that individuals consistently differ in their expression of the stress-induced rise in T(b) and that the extent of its expression is affected by factors related to heat production and dissipation. We highlight some research constraints and opportunities related to the integration of this laboratory paradigm into physiological and evolutionary ecology.

  17. Future sea-level rise in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Galassi, Gaia; Spada, Giorgio

    2014-05-01

    Secular sea level variations in the Mediterranean Sea are the result of a number of processes characterized by distinct time scales and spatial patterns. Here we predict the future sea level variations in the Mediterranean Sea to year 2050 combining the contributions from terrestrial ice melt (TIM), glacial isostatic adjustment (GIA), and the ocean response (OR) that includes the thermal expansion and the ocean circulation contributions. The three contributions are characterized by comparable magnitudes but distinctly different sea-level fingerprints across the Mediterranean basin. The TIM component of future sea-level rise is taken from Spada et al. (2013) and it is mainly driven by the melt of small glaciers and ice caps and by the dynamic ice loss from Antarctica. The sea-level fingerprint associated with GIA is studied using two distinct models available from the literature: ICE-5G(VM2) (Peltier, 2004) and the ice model progressively developed at the Research School of Earth Sciences (RSES) of the National Australian University (KL05) (see Fleming and Lambeck, 2004 and references therein). Both the GIA and the TIM sea-level predictions have been obtained with the aid of the SELEN program (Spada and Stocchi, 2007). The spatially-averaged OR component, which includes thermosteric and halosteric sea-level variations, recently obtained using a regional coupled ocean-atmosphere model (Carillo et al., 2012), vary between 2 and 7 cm according to scenarios adopted (EA1B and EA1B2, see Meehl at al., 2007). Since the sea-level variations associated with TIM mainly result from the gravitational interactions between the cryosphere components, the oceans and the solid Earth, and long-wavelength rotational variations, they are characterized by a very smooth global pattern and by a marked zonal symmetry reflecting the dipole geometry of the ice sources. Since the Mediterranean Sea is located in the intermediate far-field of major ice sources, TIM sea-level changes have sub

  18. Evidence of thermonuclear flame spreading on neutron stars from burst rise oscillations

    SciTech Connect

    Chakraborty, Manoneeta; Bhattacharyya, Sudip E-mail: sudip@tifr.res.in

    2014-09-01

    Burst oscillations during the rising phases of thermonuclear X-ray bursts are usually believed to originate from flame spreading on the neutron star surface. However, the decrease of fractional oscillation amplitude with rise time, which provides a main observational support for the flame spreading model, have so far been reported from only a few bursts. Moreover, the non-detection and intermittent detections of rise oscillations from many bursts are not yet understood considering the flame spreading scenario. Here, we report the decreasing trend of fractional oscillation amplitude from an extensive analysis of a large sample of Rossi X-ray Timing Explorer Proportional Counter Array bursts from 10 neutron star low-mass X-ray binaries. This trend is 99.99% significant for the best case, which provides, to the best of our knowledge, by far the strongest evidence of such a trend. Moreover, it is important to note that an opposite trend is not found in any of the bursts. The concave shape of the fractional amplitude profiles for all the bursts suggests latitude-dependent flame speeds, possibly due to the effects of the Coriolis force. We also systematically study the roles of low fractional amplitude and low count rate for non-detection and intermittent detections of rise oscillations, and attempt to understand them within the flame spreading scenario. Our results support a weak turbulent viscosity for flame spreading, and imply that burst rise oscillations originate from an expanding hot spot, thus making these oscillations a more reliable tool to constrain the neutron star equations of state.

  19. Responses of coastal wetlands to rising sea level

    USGS Publications Warehouse

    Morris, J.T.; Sundareshwar, P.V.; Nietch, C.T.; Kjerfve, B.; Cahoon, D.R.

    2002-01-01

    Salt marsh ecosystems are maintained by the dominant macrophytes that regulate the elevation of their habitat within a narrow portion of the intertidal zone by accumulating organic matter and trapping inorganic sediment. The long-term stability of these ecosystems is explained by interactions among sea level, land elevation, primary production, and sediment accretion that regulate the elevation of the sediment surface toward an equilibrium with mean sea level. We show here in a salt marsh that this equilibrium is adjusted upward by increased production of the salt marsh macrophyte Spartina alterniflora and downward by an increasing rate of relative sea-level rise (RSLR). Adjustments in marsh surface elevation are slow in comparison to interannual anomalies and long-period cycles of sea level, and this lag in sediment elevation results in significant variation in annual primary productivity. We describe a theoretical model that predicts that the system will be stable against changes in relative mean sea level when surface elevation is greater than what is optimal for primary production. When surface elevation is less than optimal, the system will be unstable. The model predicts that there is an optimal rate of RSLR at which the equilibrium elevation and depth of tidal flooding will be optimal for plant growth. However, the optimal rate of RSLR also represents an upper limit because at higher rates of RSLR the plant community cannot sustain an elevation that is within its range of tolerance. For estuaries with high sediment loading, such as those on the southeast coast of the United States, the limiting rate of RSLR was predicted to be at most 1.2 cm/yr, which is 3.5 times greater than the current, long-term rate of RSLR.

  20. Transition zone S velocity structure beneath the East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Grand, S. P.; Brandt, M. B.

    2009-12-01

    Models of seismic velocity as a function of depth through the upper mantle provide some of the strongest constraints on the mineralogy and composition of the mantle. Although receiver function studies have provided new information on the depths of upper mantle discontinuities they do not provide as much information on seismic gradients and velocities in the upper mantle. The waveforms and travel times of upper mantle turning waves provide the strongest constraints on vertical variations in upper mantle velocity although in the past they suffered from the lack of dense profiles of data sampling a single part of the upper mantle that would minimize effects of 3D variations in velocity. Here we model a dense profile of triplicated upper mantle broadband S waves recorded by USArray and NARS-Baja stations in the western United States and Mexico. Earthquakes along the East Pacific Rise were recorded along profiles within 5 degree backazimuth windows with stations at a maximum of .5 degree separation. The distance range covered is from 30 to 60 degrees and thus the waves sample the mantle from the lithosphere to depths near 1000 km. The data were inverted using a conjugate gradient algorithm that utilizes the reflectivity synthetic technique. The results show a much smaller gradient within the transition zone than PREM with larger jumps in velocity at the 410 and 660 km depth discontinuities. These results are more consistent with velocities predicted for a pyrolite composition than the PREM model. Between pyrolite and piclogite, our results are far more consistent with velocities predicted for a pyrolite composition.

  1. Vestibulopathy and age effects on head stability during chair rise.

    PubMed

    McGibbon, C A; Krebs, D E; Scarborough, D M

    2001-01-01

    It is unknown how vestibular dysfunction and age differentially affect balance control during functional activities. The objective of this study was to gain insight into the effects of age and vestibulopathy on head control when rising from a chair. Head relative to trunk (head-on-trunk) sagittal plane angular and linear control strategies were studied in patients with bilateral vestibular hypofunction (BVH) and in healthy subjects aged 30-80 years. A two-way analysis of variance was used to compare head-on-trunk kinematics by age (young vs elderly) and diagnosis (healthy vs BVH) at the time of liftoff from the seat. Angular control strategies differed with age but not diagnosis: young (healthy and BVH) subjects stabilized head rotations in space while elderly (healthy and BVH) subjects stabilized head rotations on the trunk. In contrast, linear control strategies differed by diagnosis but not age: BVH subjects (young and old) allowed a greater rate of head-on-trunk translation while healthy subjects (young and old) inhibited such translations. Young BVH subjects stabilized head-in-space rotations (as did young healthy subjects) without a functioning vestibular system, suggesting cervicocollic reflex and/or other sensory compensation for vestibular loss. Elderly BVH subjects stabilized head rotation with respect to the trunk, as did healthy elders, but did not stabilize head-on-trunk translations, suggesting a reliance on passive mechanical responses of the neck to sense head movements. We conclude that compensation strategies used by patients with vestibulopathy are age-dependent and appear to be more tractable in the younger BVH patient.

  2. Rise to dominance of angiosperm pioneers in European Cretaceous environments.

    PubMed

    Coiffard, Clément; Gomez, Bernard; Daviero-Gomez, Véronique; Dilcher, David L

    2012-12-18

    The majority of environments are dominated by flowering plants today, but it is uncertain how this dominance originated. This increase in angiosperm diversity happened during the Cretaceous period (ca. 145-65 Ma) and led to replacement and often extinction of gymnosperms and ferns. We propose a scenario for the rise to dominance of the angiosperms from the Barremian (ca. 130 Ma) to the Campanian (ca. 84 Ma) based on the European megafossil plant record. These megafossil data demonstrate that angiosperms migrated into new environments in three phases: (i) Barremian (ca. 130-125 Ma) freshwater lake-related wetlands; (ii) Aptian-Albian (ca. 125-100 Ma) understory floodplains (excluding levees and back swamps); and (iii) Cenomanian-Campanian (ca. 100-84 Ma) natural levees, back swamps, and coastal swamps. This scenario allows for the measured evolution of angiosperms in time and space synthesizing changes in the physical environment with concomitant changes in the biological environment. This view of angiosperm radiation in three phases reconciles previous scenarios based on the North American record. The Cretaceous plant record that can be observed in Europe is exceptional in many ways. (i) Angiosperms are well preserved from the Barremian to the Maastrichtian (ca. 65 Ma). (ii) Deposits are well constrained and dated stratigraphically. (iii) They encompass a full range of environments. (iv) European paleobotany provides many detailed studies of Cretaceous floras for analysis. These factors make a robust dataset for the study of angiosperm evolution from the Barremian to the Campanian that can be traced through various ecosystems and related to other plant groups occupying the same niches.

  3. Rise to dominance of angiosperm pioneers in European Cretaceous environments

    PubMed Central

    Coiffard, Clément; Gomez, Bernard; Daviero-Gomez, Véronique; Dilcher, David L.

    2012-01-01

    The majority of environments are dominated by flowering plants today, but it is uncertain how this dominance originated. This increase in angiosperm diversity happened during the Cretaceous period (ca. 145–65 Ma) and led to replacement and often extinction of gymnosperms and ferns. We propose a scenario for the rise to dominance of the angiosperms from the Barremian (ca. 130 Ma) to the Campanian (ca. 84 Ma) based on the European megafossil plant record. These megafossil data demonstrate that angiosperms migrated into new environments in three phases: (i) Barremian (ca. 130–125 Ma) freshwater lake-related wetlands; (ii) Aptian–Albian (ca. 125–100 Ma) understory floodplains (excluding levees and back swamps); and (iii) Cenomanian–Campanian (ca. 100–84 Ma) natural levees, back swamps, and coastal swamps. This scenario allows for the measured evolution of angiosperms in time and space synthesizing changes in the physical environment with concomitant changes in the biological environment. This view of angiosperm radiation in three phases reconciles previous scenarios based on the North American record. The Cretaceous plant record that can be observed in Europe is exceptional in many ways. (i) Angiosperms are well preserved from the Barremian to the Maastrichtian (ca. 65 Ma). (ii) Deposits are well constrained and dated stratigraphically. (iii) They encompass a full range of environments. (iv) European paleobotany provides many detailed studies of Cretaceous floras for analysis. These factors make a robust dataset for the study of angiosperm evolution from the Barremian to the Campanian that can be traced through various ecosystems and related to other plant groups occupying the same niches. PMID:23213256

  4. Fires and the rise and regulation of atmospheric oxygen

    NASA Astrophysics Data System (ADS)

    Lenton, T. M.

    2012-04-01

    When did oxygen first approach 21% of the atmosphere, and what regulates it there? These are enduring puzzles in Earth system science, and fire science provides a key part of the answers. The results of ignition experiments with natural fuels indicate that to start a fire requires at least 17% oxygen in the atmosphere. Thus, the appearance of charcoal in the fossil record around 420 million years ago in the Silurian Period indicates atmospheric oxygen was >17% then. Here we hypothesise that the first non-vascular plants, which began colonising the land surface around 50 million years beforehand (in the Ordovician Period), caused a rise in atmospheric oxygen concentration to a level >17% sufficient to support fires. We base this on weathering experiments with an analogue for the first non-vascular plants, and modelling with the COPSE model of the coupled phosphorus, carbon and oxygen biogeochemical cycles. The experiments reveal that a non-vascular plant (the moss Physcomitrella patens) hugely amplifies phosphorus weathering by a factor of up to 60. The modelling shows that early plant colonisation could hence have increased phosphorus supply to the ocean, fuelling photosynthetic production and organic carbon burial, which is the long-term source of oxygen to the atmosphere. Atmospheric oxygen is predicted to have risen through the late Ordovician and into the Silurian. Since 370 million years ago, the nearly continuous record of charcoal indicates that oxygen has remained above 17% of the atmosphere. At the same time, the continued persistence of forests means fires have never been so frequent as to prevent trees from regenerating, setting a contested upper limit on oxygen of around 30%. The restriction of oxygen variation within a factor of two suggests remarkable regulation, because the whole oxygen reservoir has been replaced over 100 times in this interval. Fires are a prime candidate for forming part of the regulating mechanism, and giving it a 'set point', as

  5. Complexities in Barrier Island Response to Sea-Level Rise: Insights from Model Experiments

    NASA Astrophysics Data System (ADS)

    Moore, L. J.; List, J. H.; Williams, S. J.

    2008-12-01

    As sea level rises, a barrier island will respond either by migrating landward across the underlying substrate to higher elevations or by disintegrating if there is no longer sufficient sand volume and relief above sea level to prevent inundation during storms. Using the morphological-behavior model GEOMBEST, we investigate the sea-level rise response of a complex coastal environment to changes in variety of factors, thus yielding insights into barrier island evolution. Our base case is a simplified Holocene run which simulates a possible scenario for the evolution of a 25-km stretch of the North Carolina Outer Banks over the last 8500 years. Varying one parameter at a time, we explore the degree to which changes in sea-level rise rate, sediment supply/loss rate, offshore limits to sediment transport, substrate erodibility, substrate composition and depth- dependent response rate produce changes in average landward barrier island migration rate, average depth of substrate erosion, and final barrier island volume. As expected, sensitivity analyses reveal that within the range of possible values for the North Carolina coast, sea-level rise rate, followed by sediment supply rate, is the most important factor in determining barrier island response to sea-level rise. More surprisingly, the analyses in aggregate indicate that barrier island evolution is highly sensitive to the range of substrate slopes encountered throughout landward migration (i.e., the slope history); as a barrier encounters a continually changing substrate slope, island volume constantly changes, moving toward equilibrium with the current average slope. Through this process, steeper average slope histories produce smaller barrier islands while shallower average slope histories produce larger barrier islands. In both cases, secondary effects on substrate erosion depth and migration rate also result. Notably, similar geometric effects explain an insensitivity of simulation results to changes in offshore

  6. Hydrothermal plume particles and dissolved phosphate over the superfast-spreading southern East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Feely, R. A.; Baker, E. T.; Marumo, K.; Urabe, T.; Ishibashi, J.; Gendron, J.; Lebon, G. T.; Okamura, K.

    1996-07-01

    The distribution and elemental composition of hydrothermal plume particles were mapped along the superfast spreading southern East Pacific Rise from the Garret Transform Fault to ˜19°S. Hydrographic and optical data were obtained using a series of seven tow-yos and thirty vertical casts employing a rosette sampler with 19-L PVC bottles for collecting discrete samples of various dissolved and particulate hydrothermal species. The extent of hydrothermal plume coverage over the southern East Pacific Rise between 13°33' and 18°40'S is significantly greater than in other ridgecrest systems. The region south of 17°20'S is characterized by significant enrichments of volatile gases resulting from magmatic input of fresh lava at the seafloor. Between 17°20' and 18°40'S, the ratio of S/Fe in the plume particles is highly correlated with the dissolved gases in the neutrally-buoyant hydrothermal plumes. Plume inventories of Fe and S over this portion of the southern East Pacific Rise are 6-150 times higher than what has been observed over other vent fields because the total abundance of plumes is much greater. In addition, significant depletions (> 100 nmol/L) of dissolved phosphate over the ridge axis were observed at the depth of the hydrothermal plumes. These results provide clear evidence that this section of the southern East Pacific Rise maintains the most extensive complex of hydrothermal plumes observed thus far on the global ridgecrest system.

  7. Mass and volume contributions to twentieth-century global sea level rise.

    PubMed

    Miller, Laury; Douglas, Bruce C

    2004-03-25

    The rate of twentieth-century global sea level rise and its causes are the subjects of intense controversy. Most direct estimates from tide gauges give 1.5-2.0 mm yr(-1), whereas indirect estimates based on the two processes responsible for global sea level rise, namely mass and volume change, fall far below this range. Estimates of the volume increase due to ocean warming give a rate of about 0.5 mm yr(-1) (ref. 8) and the rate due to mass increase, primarily from the melting of continental ice, is thought to be even smaller. Therefore, either the tide gauge estimates are too high, as has been suggested recently, or one (or both) of the mass and volume estimates is too low. Here we present an analysis of sea level measurements at tide gauges combined with observations of temperature and salinity in the Pacific and Atlantic oceans close to the gauges. We find that gauge-determined rates of sea level rise, which encompass both mass and volume changes, are two to three times higher than the rates due to volume change derived from temperature and salinity data. Our analysis supports earlier studies that put the twentieth-century rate in the 1.5-2.0 mm yr(-1) range, but more importantly it suggests that mass increase plays a larger role than ocean warming in twentieth-century global sea level rise.

  8. Tension between reducing sea-level rise and global warming through solar-radiation management

    NASA Astrophysics Data System (ADS)

    Irvine, P. J.; Sriver, R. L.; Keller, K.

    2012-02-01

    Geoengineering using solar-radiation management (SRM) is gaining interest as a potential strategy to reduce future climate change impacts. Basic physics and past observations suggest that reducing insolation will, on average, cool the Earth. It is uncertain, however, whether SRM can reduce climate change stressors such as sea-level rise or rates of surface air temperature change. Here we use an Earth system model of intermediate complexity to quantify the possible response of sea levels and surface air temperatures to projected climate forcings and SRM strategies. We find that SRM strategies introduce a potentially strong tension between the objectives to reduce (1) the rate of temperature change and (2) sea-level rise. This tension arises primarily because surface air temperatures respond faster to radiative forcings than sea levels. Our results show that the forcing required to stop sea-level rise could cause a rapid cooling with a rate similar to the peak business-as-usual warming rate. Furthermore, termination of SRM was found to produce warming rates up to five times greater than the maximum rates under the business-as-usual CO2 scenario, whereas sea-level rise rates were only 30% higher. Reducing these risks requires a slow phase-out of many decades and thus commits future generations.

  9. Color imaging of Mars by the High Resolution Imaging Science Experiment (HiRISE)

    USGS Publications Warehouse

    Delamere, W.A.; Tornabene, L.L.; McEwen, A.S.; Becker, K.; Bergstrom, J.W.; Bridges, N.T.; Eliason, E.M.; Gallagher, D.; Herkenhoff, K. E.; Keszthelyi, L.; Mattson, S.; McArthur, G.K.; Mellon, M.T.; Milazzo, M.; Russell, P.S.; Thomas, N.

    2010-01-01

    HiRISE has been producing a large number of scientifically useful color products of Mars and other planetary objects. The three broad spectral bands, coupled with the highly sensitive 14 bit detectors and time delay integration, enable detection of subtle color differences. The very high spatial resolution of HiRISE can augment the mineralogic interpretations based on multispectral (THEMIS) and hyperspectral datasets (TES, OMEGA and CRISM) and thereby enable detailed geologic and stratigraphic interpretations at meter scales. In addition to providing some examples of color images and their interpretation, we describe the processing techniques used to produce them and note some of the minor artifacts in the output. We also provide an example of how HiRISE color products can be effectively used to expand mineral and lithologic mapping provided by CRISM data products that are backed by other spectral datasets. The utility of high quality color data for understanding geologic processes on Mars has been one of the major successes of HiRISE. ?? 2009 Elsevier Inc.

  10. Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise.

    PubMed

    Donnelly, J P; Bertness, M D

    2001-12-04

    The distribution of New England salt marsh communities is intrinsically linked to the magnitude, frequency, and duration of tidal inundation. Cordgrass (Spartina alterniflora) exclusively inhabits the frequently flooded lower elevations, whereas a mosaic of marsh hay (Spartina patens), spike grass (Distichlis spicata), and black rush (Juncus gerardi) typically dominate higher elevations. Monitoring plant zonal boundaries in two New England salt marshes revealed that low-marsh cordgrass rapidly moved landward at the expense of higher-marsh species between 1995 and 1998. Plant macrofossils from sediment cores across modern plant community boundaries provided a 2,500-year record of marsh community composition and documented the migration of cordgrass into the high marsh. Isotopic dating revealed that the initiation of cordgrass migration occurred in the late 19th century and continued through the 20th century. The timing of the initiation of cordgrass migration is coincident with an acceleration in the rate of sea-level rise recorded by the New York tide gauge. These results suggest that increased flooding associated with accelerating rates of sea-level rise has stressed high-marsh communities and promoted landward migration of cordgrass. If current rates of sea-level rise continue or increase slightly over the next century, New England salt marshes will be dominated by cordgrass. If climate warming causes sea-level rise rates to increase significantly over the next century, these cordgrass-dominated marshes will likely drown, resulting in extensive losses of coastal wetlands.

  11. Tidal regime deformation by sea level rise along the coast of the Mekong Delta

    NASA Astrophysics Data System (ADS)

    Nhan, Nguyen Huu

    2016-12-01

    The future of river deltas is believed to depend mainly on sea level rise (SLR) and on the processes controlling the adaptation of the substrate to human impacts. The deltas are increasingly deprived of riverine sediment by river diversion, dams, dykes and the destruction of wetlands, and they are often sinking due to mining for groundwater, gas and petroleum. The relative sea level rise is causing severe negative impacts in many river deltas worldwide. With continuously rising sea levels, this impact is expected to increase over time. The increased risk of delta flooding caused by tidal deformation associated with SLR in shallow coastal waters has received less attention. In this study, we demonstrate this effect for the case of the Mekong Delta where this study suggests that the maximum tidal water level and the tidal amplitude are increasing while the tidal phase at the coast is decreasing. In addition, the maximum water levels is rising faster than SLR because the tides themselves are modified by SLR. This effect is particularly pronounced for semi-diurnal tides and less so for diurnal tides. Similar effects may prevail for river deltas with extensive shallow coastal waters elsewhere in the world and deserve further investigation.

  12. Scaling law for bubbles rising near vertical walls

    NASA Astrophysics Data System (ADS)

    Dabiri, Sadegh; Bhuvankar, Pramod

    2016-06-01

    This paper examines the rising motion of a layer of gas bubbles next to a vertical wall in a liquid in the presence of an upward flow parallel to the wall to help with the understanding of the fluid dynamics in a bubbly upflow in vertical channels. Only the region near the wall is simulated with an average pressure gradient applied to the domain that balances the weight of the liquid phase. The upward flow is created by the rising motion of the bubbles. The bubbles are kept near the wall by the lateral lift force acting on them as a result of rising in the shear layer near the wall. The rise velocity of the bubbles sliding on the wall and the average rise velocity of the liquid depend on three dimensionless parameters, Archimedes number, Ar, Eötvös number, Eo, and the average volume fraction of bubbles on the wall. In the limit of small Eo, bubbles are nearly spherical and the dependency on Eo becomes negligible. In this limit, the scaling of the liquid Reynolds number with Archimedes number and the void fraction is presented. A scaling argument is presented based on viscous dissipation analysis that matches the numerical findings. Viscous dissipation rates are found to be high in a thin film region between the bubble and the wall. A scaling of the viscous dissipation and steady state film thickness between the bubble and the wall with Archimedes number is presented.

  13. Rising sea level may cause decline of fringing coral reefs

    NASA Astrophysics Data System (ADS)

    Field, Michael E.; Ogston, Andrea S.; Storlazzi, Curt D.

    2011-08-01

    Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but sea level rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century sea level rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that sea level will rise in the coming century (1990-2090) by 2.2-4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of sea level rise [Grinsted et al., 2009; Milne et al., 2009].

  14. Blood glucose rise after lactose tolerance testing in infants.

    PubMed

    Paige, D M; Mellits, E D; Chiu, F Y; Davis, L; Bayless, T M; Cordano, A

    1978-02-01

    Lactose tolerance tests are used clinically to screen children and infants. It is assumed that absorption of a lactose challenge in infants would occur in a predictable pattern prior to weaning. Twenty-one infants from 3 to 12 months of age were studied. The maximum blood glucose rise over fasting levels ranged from 11.0 to 62.0 mg/100 ml; the mean was 32.6 mg/100 ml. Six infants had a maximum rise of less than 20 mg/100 ml. Eleven infants (52%) had a maximum rise of greater than 30 mg/100 ml. Signs of intolerance were not noted in any subject. Weight and length were normally disturbed. Results indicate the variance in glucose rise existing within a population of infants growing normally and consuming milk. Gastric emptying, digestion, and absorption may influence the blood glucose rise after a lactose test. Established glucose levels used as an index to lactose absorption in older children and adults may not accurately reflect lactase activity in infants.

  15. Rising sea level may cause decline of fringing coral reefs

    USGS Publications Warehouse

    Field, Michael E.; Ogston, Andrea S.; Storlazzi, Curt D.

    2011-01-01

    Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but sea level rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century sea level rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that sea level will rise in the coming century (1990–2090) by 2.2–4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of sea level rise [Grinsted et al., 2009; Milne et al., 2009].

  16. Rising sea level may cause decline of fringing coral reefs

    USGS Publications Warehouse

    Field, M.E.; Ogston, A.S.; Storlazzi, C.D.

    2011-01-01

    Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but sea level rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century sea level rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that sea level will rise in the coming century (1990-2090) by 2.2-4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of sea level rise [Grinsted et al., 2009; Milne et al., 2009].

  17. Speculative Truth - Henry Cavendish, Natural Philosophy, and the Rise of Modern Theoretical Science

    NASA Astrophysics Data System (ADS)

    McCormmach, Russell

    2004-03-01

    With a never-before published paper by Lord Henry Cavendish, as well as a biography on him, this book offers a fascinating discourse on the rise of scientific attitudes and ways of knowing. A pioneering British physicist in the late 18th and early 19th centuries, Cavendish was widely considered to be the first full-time scientist in the modern sense. Through the lens of this unique thinker and writer, this book is about the birth of modern science.

  18. Rising premature mortality in the U.K.'s persistently deprived areas: only a Scottish phenomenon?

    PubMed

    Norman, Paul; Boyle, Paul; Exeter, Daniel; Feng, Zhiqiang; Popham, Frank

    2011-12-01

    In the international literature, many studies find strong relationships between area-based measures of deprivation and mortality. In the U.K., mortality rates have generally fallen in recent decades but the life expectancy gap between the most and least deprived areas has widened, with a number of Scottish studies highlighting increased mortality rates in deprived areas especially in Glasgow. However, these studies relate health outcomes at different time points against period-specific measures of deprivation which may not be comparable over time. Using longitudinal deprivation measures where levels of area deprivation are made comparable over time, a recent study demonstrated how levels of mortality change in relation to changing or persistent levels of (non-) deprivation over time. The results showed that areas which were persistently deprived in Scotland experienced a rise in premature mortality rates by 9.5% between 1981 and 2001. Here, focussing on persistently deprived areas we extended the coverage to the whole of the U.K. to assess whether, between 1991 and 2001, rising premature mortality rates in persistently deprived areas are a Scottish only phenomenon or whether similar patterns are evident elsewhere and for men and women separately. We found that male premature mortality rates rose by over 14% in Scotland over the 10-year period between the early 1990s and 2000s in persistently deprived areas. We found no significant rise in mortality elsewhere in the U.K. and that the rise among men in Scotland was driven by results for Glasgow where mortality rates rose by over 15% during the decade. Our analyses demonstrate the importance of identifying areas experiencing persistent poverty. These results justify even more of a public health focus on Glasgow and further work is needed to understand the demographic factors, such as health selective migration, immobility and population residualisation, which may contribute to these findings.

  19. Dynamics of liquid rise in a vertical capillary tube.

    PubMed

    Masoodi, Reza; Languri, Ehsan; Ostadhossein, Alireza

    2013-01-01

    The governing equation for capillary rise in a vertical tube is derived using energy balance. The derived governing equation includes kinetic, gravity, and viscous effects. Through normalizing different terms in the governing equation, a form of nonlinear ordinary differential equation (ODE) with a positive dimensionless parameter was obtained. The ODE equation was solved numerically and the numerical results were compared with some published experimental data. The derived governing equation was found to be quite accurate for predicting the liquid rise and oscillation in a capillary tube. The effect of a dimensionless parameter on the behavior of the liquid rise was explored numerically. A simple critical condition, which leads to the oscillation of the liquid column in the capillary tube, was found in the form of a dimensionless parameter in the governing equation.

  20. Overestimation of marsh vulnerability to sea level rise

    NASA Astrophysics Data System (ADS)

    Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio

    2016-03-01

    Coastal marshes are considered to be among the most valuable and vulnerable ecosystems on Earth, where the imminent loss of ecosystem services is a feared consequence of sea level rise. However, we show with a meta-analysis that global measurements of marsh elevation change indicate that marshes are generally building at rates similar to or exceeding historical sea level rise, and that process-based models predict survival under a wide range of future sea level scenarios. We argue that marsh vulnerability tends to be overstated because assessment methods often fail to consider biophysical feedback processes known to accelerate soil building with sea level rise, and the potential for marshes to migrate inland.

  1. Pancreatic rupture in four cats with high-rise syndrome.

    PubMed

    Liehmann, Lea M; Dörner, Judith; Hittmair, Katharina M; Schwendenwein, Ilse; Reifinger, Martin; Dupré, Gilles

    2012-02-01

    Pancreatic trauma and rupture are rare after feline high-rise syndrome; however, should it happen, pancreatic enzymes will leak into the abdominal cavity and may cause pancreatic autodigestion and fatty tissue saponification. If not diagnosed and treated, it can ultimately lead to multiorgan failure and death. In this case series, 700 records of high-rise syndrome cats that presented between April 2001 and May 2006 were analysed, and four cats with pancreatic rupture were identified. Clinical signs, diagnosis using ultrasonography and lipase activity in blood and abdominal effusion, and treatment modalities are reported. Three cats underwent surgical abdominal exploration, one cat was euthanased. Rupture of the left pancreatic limb was confirmed in all cases. Two of the operated cats survived to date. High-rise syndrome can lead to abdominal trauma, including pancreatic rupture. A prompt diagnosis and surgical treatment should be considered.

  2. Overestimation of marsh vulnerability to sea level rise

    USGS Publications Warehouse

    Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio

    2016-01-01

    Coastal marshes are considered to be among the most valuable and vulnerable ecosystems on Earth, where the imminent loss of ecosystem services is a feared consequence of sea level rise. However, we show with a meta-analysis that global measurements of marsh elevation change indicate that marshes are generally building at rates similar to or exceeding historical sea level rise, and that process-based models predict survival under a wide range of future sea level scenarios. We argue that marsh vulnerability tends to be overstated because assessment methods often fail to consider biophysical feedback processes known to accelerate soil building with sea level rise, and the potential for marshes to migrate inland.

  3. Who is to blame for the rise in obesity?

    PubMed

    Lusk, Jayson L; Ellison, Brenna

    2013-09-01

    We sought to determine who the public perceives as most contributing to the rise in obesity and to identify the determinants of such perceptions. A nationwide survey was conducted among 800 US individuals. Respondents were asked to place each of seven entities (food manufacturers, grocery stores, restaurants, government policies, farmers, individuals, and parents) into three categories: primarily, somewhat, and not to blame for the rise in obesity. Eighty percent said individuals were primarily to blame for the rise in obesity. Parents were the next-most blameworthy group, with 59% ascribing primary blame. Responses fell along three dimensions related to individual responsibility, agribusiness responsibility, and government-farm policy. A number of individual-specific factors were associated with perceptions of blame. For example, individuals with a more statist score on the economic political ideology scale were more likely to blame the government and agribusiness for obesity.

  4. Plume rise, entrainment and dispersion in turbulent winds

    NASA Astrophysics Data System (ADS)

    Netterville, Dennett D. J.

    This paper describes a new analytical model which combines within one theoretical framework several aspects of the phenomena of plume rise, dispersion, thermal stratification and ambient turbulence. The model is based in part on knowledge gained from recent investigations of flow within free shear layers. The observations suggest a simple model for the turbulent mixing process, which accounts for the known entrainment of air into smoke plumes by plume-generated turbulence. More importantly, the model also predicts a path by which ambient turbulence causes reverse entrainment of plume material into the surrounding fluids. This gives rise to a new 'extrainment' term in each of the plume momentum and buoyancy equations. These equations are solved for a turbulent atmosphere of arbitrary thermal stability, and yield plume trajectories which gradually level off at final rise heights that depend on the degree of thermal stratification and on the scale and intensity of ambient turbulence. A link between plume rise and dispersion is identified by means of the concentration species equation, which is solved to show that the plume acts along its length as a distributed source of passively dispersing material. The new theory, specialized for an adiabatic atmosphere, plus the familiar x2/3 law and a semi-empirical final rise theory from the literature, are all compared against full-scale data on plume rise in turbulent winds. The new theory significantly improves the accuracy of estimates of plume trajectory and final plume height. The price for this improved predictive ability is the need to evaluate the air temperature and its gradient at plume level, and the corresponding intensity and scale of turbulent air movement. This is no longer a technical obstacle since recently developed SODAR and RASS remote sensors have this capability.

  5. Line shapes and time dynamics of the Förster resonances between two Rydberg atoms in a time-varying electric field

    NASA Astrophysics Data System (ADS)

    Yakshina, E. A.; Tretyakov, D. B.; Beterov, I. I.; Entin, V. M.; Andreeva, C.; Cinins, A.; Markovski, A.; Iftikhar, Z.; Ekers, A.; Ryabtsev, I. I.

    2016-10-01

    The observation of the Stark-tuned Förster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the Förster resonance. In our experiments with a few cold Rb Rydberg atoms, we have found that the transients at the edges of the electric pulses strongly affect the line shapes of the Förster resonances, since the population transfer at the resonances occurs on a time scale of ˜100 ns, which is comparable with the duration of the transients. For example, a short-term ringing at a certain frequency causes additional radio-frequency-assisted Förster resonances, while nonsharp edges lead to asymmetry. The intentional application of the radio-frequency field induces transitions between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a single interaction volume yields a cusped line shape of the Förster resonance. We present a detailed experimental and theoretical analysis of the line shape and time dynamics of the Stark-tuned Förster resonances Rb (n P3 /2) +Rb (n P3 /2) →Rb (n S1 /2) +Rb ([n +1 ] S1 /2) for two Rb Rydberg atoms interacting in a time-varying electric field.

  6. Dynamics of Volcanic Jets from Short-Duration Eruptions: Mixing and Rise

    NASA Astrophysics Data System (ADS)

    Chojnicki, K. N.; Gisler, G. R.; Ogden, D.

    2014-12-01

    Mixing controls volcanic plume behavior. Our understanding of mixing therefore places a critical limit on our capacity to manage volcanic plume hazards. Researchers have investigated mixing for two situations: volcanic plumes with rise times that are long or short relative to the eruption duration. The plumes generated in these two situations are then modeled as thermals or maintained plumes, respectively. The case in the middle, when plume rise times are comparable to the eruption durations, is not often considered. This third class is appropriate to discrete eruptions, such as Strombolian- or Vulcanian-style eruptions, which last a few seconds or tens of seconds and generate relatively small plumes. Here we use numerical experiments to show that mixing occurs differently in this third eruption class because of dynamic features that are distinct from the long- and instantaneous-duration end members. In this presentation we focus on the effect of eruption duration on mixing in the inertia-driven or jet-like phase of ascending volcanic plumes. Our simulation results reveal that air entrainment rates increase after the eruption ends, resulting in enhanced overall mixing in jets from shorter-duration eruptions. Models developed for the other two mixing situations do not predict these results. New models are required for volcanic plumes with rise times comparable to their durations in order to reliably estimate their behavior for hazard management purposes.

  7. Coastal flooding by tropical cyclones and sea-level rise.

    PubMed

    Woodruff, Jonathan D; Irish, Jennifer L; Camargo, Suzana J

    2013-12-05

    The future impacts of climate change on landfalling tropical cyclones are unclear. Regardless of this uncertainty, flooding by tropical cyclones will increase as a result of accelerated sea-level rise. Under similar rates of rapid sea-level rise during the early Holocene epoch most low-lying sedimentary coastlines were generally much less resilient to storm impacts. Society must learn to live with a rapidly evolving shoreline that is increasingly prone to flooding from tropical cyclones. These impacts can be mitigated partly with adaptive strategies, which include careful stewardship of sediments and reductions in human-induced land subsidence.

  8. Surfactant-laden drops rising in a stratified ambient

    NASA Astrophysics Data System (ADS)

    Blanchette, Francois; Martin, David

    2015-11-01

    We present results of a numerical study of the dynamics of rising drops in the presence of both surfactants and stratification. Our simulations model oil drops rising in the oceans, where naturally occurring or man-made surfactants are present. We study surfactant covered drops in uniform and density-stratified ambients, as well as clean drops entering a dissolved surfactant layer. We quantify the effects of entrainment for various Reynolds and Marangoni numbers. We also report a brief acceleration followed by a significant deceleration as a clean drop enters a surfactant layer, and describe how the adsorption rate affects those dynamics.

  9. Ore potential of the Marcus-Wake rise (Central Pacific)

    NASA Astrophysics Data System (ADS)

    Novikov, G. V.; Mel'nikov, M. E.; Lobkovsky, L. I.; Bogdanova, O. Yu.; Sorokhtin, N. O.

    2015-12-01

    The data on the geological structure of different guyots on the Marcus-Wake rise with cobalt-bearing Fe-Mn crusts are discussed. Crusts are represented by three-layer aggregates composed of one lower phosphatized (I-1) and two upper non-phosphatized (II and III) layers. Fe-vernadite and Mn-feroxygite are the major ore minerals in all studied crusts and their layers. Small contents of vernadite, asbolane-buserite, and goethite are registered. Crusts of guyots on the rise are characterized by a stable concentration of heavy and rare metals (Cotot, Ni, Cu, Zn, Pb, Mo, and Cd) independently of their latitudinal location.

  10. Deciphering The Fall And Rise Of The Dead Sea In Relation To Solar Forcing

    NASA Astrophysics Data System (ADS)

    Yousef, Shahinaz M.

    2005-03-01

    Solar Forcing on closed seas and Lakes is space time dependent. The Cipher of the Dead Sea level variation since 1200 BC is solved in the context of millenium and Wolf-Gleissberg solar cycles time scales. It is found that the pattern of Dead Sea level variation follows the pattern of major millenium solar cycles. The 70 m rise of Dead Sea around 1AD is due to the forcing of the maximum millenium major solar cycle. Although the pattern of the Dead Sea level variation is almost identical to major solar cycles pattern between 1100 and 1980 AD, there is a dating problem of the Dead Sea time series around 1100-1300 AD that time. A discrepancy that should be corrected for the solar and Dead Sea series to fit. Detailed level variations of the Dead Sea level for the past 200 years are solved in terms of the 80-120 years solar Wolf-Gliessberg magnetic cycles. Solar induced climate changes do happen at the turning points of those cycles. Those end-start and maximum turning points are coincident with the change in the solar rotation rate due to the presence of weak solar cycles. Such weak cycles occur in series of few cycles between the end and start of those Wolf-Gleissberg cycles. Another one or two weak r solar cycle occur following the maximum of those Wolf-Gleissberg cycles. Weak cycles induce drop in the energy budget emitted from the sun and reaching the Earth thus causing solar induced climate change. An 8 meter sudden rise of Dead Sea occur prior 1900 AD due to positive solar forcing of the second cycle of the weak cycles series on the Dead Sea. The same second weak cycle induced negative solar forcing on Lake Chad. The first weak solar cycle forced Lake Victoria to rise abruptly in 1878. The maximum turning point of the solar Wolf-Gleissberg cycle induced negative forcing on both the Aral Sea and the Dead Sea causing their shrinkage to an alarming reduced area ever since. On the other hand, few years delayed positive forcing caused Lake Chad and the Equatorial

  11. Space-based observational constraints for 1-D fire smoke plume-rise models

    NASA Astrophysics Data System (ADS)

    Val Martin, Maria; Kahn, Ralph A.; Logan, Jennifer A.; Paugam, Ronan; Wooster, Martin; Ichoku, Charles

    2012-11-01

    We use a plume height climatology derived from space-based Multiangle Imaging Spectroradiometer (MISR) observations to evaluate the performance of a widely used plume-rise model. We initialize the model with assimilated meteorological fields from the NASA Goddard Earth Observing System and estimated fuel moisture content at the location and time of the MISR measurements. Fire properties that drive the plume-rise model are difficult to constrain, and we test the model with four estimates each of active fire area and total heat flux, obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) fire radiative power (FRP) thermal anomalies available for each MISR plume and other empirical data. We demonstrate the degree to which the fire dynamical heat flux (related to active fire area and sensible heat flux) and atmospheric stability structure influence plume rise, although entrainment and possibly other less well constrained factors are also likely to be significant. Using atmospheric stability conditions, MODIS FRP, and MISR plume heights, we find that smoke plumes reaching high altitudes are characterized by higher FRP and weaker atmospheric stability conditions than those at low altitude, which tend to remain confined below the boundary layer, consistent with earlier results. However, over the diversity of conditions studied, the model simulations generally underestimate the plume height dynamic range observed by MISR and do not reliably identify plumes injected into the free troposphere, key information needed for atmospheric models to simulate smoke dispersion. We conclude that embedding in large-scale atmospheric studies an advanced plume-rise model using currently available fire constraints remains a difficult proposition, and we propose a simplified model that crudely constrains plume injection height based on two main physical factors for which some observational constraints often exist. Field experiments aimed at directly measuring fire and smoke

  12. Non-linear shape oscillations of rising drops and bubbles: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Lalanne, Benjamin; Abi Chebel, Nicolas; Vejražka, Jiří; Tanguy, Sébastien; Masbernat, Olivier; Risso, Frédéric

    2015-12-01

    This paper focuses on shape-oscillations of a gas bubble or a liquid drop rising in another liquid. The bubble/drop is initially attached to a capillary and is released by a sudden motion of that capillary, resulting in the rise of the bubble/drop along with the oscillations of its shape. Such experimental conditions make difficult the interpretation of the oscillation dynamics with regard to the standard linear theory of oscillation because (i) amplitude of deformation is large enough to induce nonlinearities, (ii) the rising motion may be coupled with the oscillation dynamics, and (iii) clean conditions without residual surfactants may not be achieved. These differences with the theory are addressed by comparing experimental observation with numerical simulation. Simulations are carried out using Level-Set and Ghost-Fluid methods with clean interfaces. The effect of the rising motion is investigated by performing simulations under different gravity conditions. Using a decomposition of the bubble/drop shape into a series of spherical harmonics, experimental and numerical time evolutions of their amplitudes are compared. Due to large oscillation amplitude, non-linear couplings between the modes are evidenced from both experimental and numerical signals; modes of lower frequency influence modes of higher frequency, whereas the reverse is not observed. Nevertheless, the dominant frequency and overall damping rate of the first five modes are in good agreement with the linear theory. Effect of the rising motion on the oscillations is globally negligible, provided the mean shape of the oscillation remains close to a sphere. In the drop case, despite the residual interface contamination evidenced by a reduction in the terminal velocity, the oscillation dynamics is shown to be unaltered compared to that of a clean drop.

  13. Shatsky Rise: Constraining Duration of Volcanism in a Jurassic Large Igneous Province

    NASA Astrophysics Data System (ADS)

    Heaton, D. E.; Koppers, A. A.

    2013-12-01

    Here we present new high-precision 40Ar/39Ar ages from Shatsky Rise, an oceanic plateau (2.7 × 106 km3) composed of three large volcanic edifices: TAMU, ORI and Shirsov Massif. TAMU Massif (~144.8 × 1.2 Ma; Mahoney et al., 2004) was the first to form at the intersection of an ancient triple junction and is now considered to be the largest singular shield volcano ever to have formed on Earth (Sager et al. 2013; accepted for publication in Nature Geosciences). ORI and Shirsov Massif appear to have formed later in time, following the northward migration of the triple junction. However, it remains unclear whether mechanisms involved in the formation of this triple junction and related mid-ocean ridge volcanism created Shatsky Rise, or whether a plume source is required to explain its significant size and volume. With the age determinations presented here we will attempt to constrain the duration of magmatism, reveal the eruption rates of the Shatsky Rise shield volcanoes, and determine the nature of the age progression along the Shatsky Rise massifs, if it exists. In addition, we will relate the Shatsky Rise volcanic history to the formation of numerous seamounts on and around the Shatsky Rise area. Overall, 50 groundmass and plagioclase separates from across Shatsky Rise and the related seamounts were carefully picked and processed. Thirty-four samples were analyzed from TAMU massif, coming from IODP Expedition 324 Site U1347 (17 samples), ODP Leg 198 Site 1213B (14 samples) and dredging cruise TN037 (3 samples). Seventeen samples were analyzed from ORI Massif, coming from IODP Expedition 324 Sites U1349 and U1350 (16 samples) and a single dredge along the flank of the massif from TN037 (1 sample). Four samples were analyzed from Shirsov Massif, all from IODP Expedition 324 Site U1346. Samples were variably altered but were treated with an extensive acid leaching regimen (Koppers et al., 2004), including 2 x 15 minutes of 5% HF treatments for plagioclases. Samples

  14. The Milliken/Georgia Tech Rising Senior Summer Program.

    ERIC Educational Resources Information Center

    Agrawal, Pradeep K; Sommerfeld, Jude T.

    1987-01-01

    Describes the Rising Senior Program at the Georgia Institute of Technology, which is a cooperative education program designed to provide student interns with an opportunity to apply engineering principles to real problems related to the business interests of the Milliken textile manufacturing company. (TW)

  15. Rising to the Challenge: Meaningful Assessment of Student Learning

    ERIC Educational Resources Information Center

    Association of Public and Land-grant Universities, 2010

    2010-01-01

    "Rising to the Challenge: Meaningful Assessment of Student Learning" was envisioned in response to a 2007 request for proposals from the U.S. Department of Education's Fund for Improvement of Post Secondary Education (FIPSE). FIPSE called for national, consortial contributions to improving the knowledge and abilities to assess student…

  16. Punishing Kids: The Rise of the "Boot Camp"

    ERIC Educational Resources Information Center

    Mills, Martin; Pini, Barbara

    2015-01-01

    This paper is concerned with the rise of 'the boot camp' as a means of addressing "the problem of troubled youth" in contemporary industrialised nations such as Australia and the UK. Drawing on a corpus of publicly available material including press releases and policy documents, media reports, and programme websites, the paper explores…

  17. Developmental Reading in Social Studies; Rise in Industry and Agriculture.

    ERIC Educational Resources Information Center

    Fried, Marian; And Others

    This unit guide, sixth in a series of seven, is designed to provide eighth-grade teachers with materials for reading and study skills instruction while developing the facts, attitudes, and concepts of social studies. Information about the rise of industry and agriculture is found in two texts: "This is America's Story," for use with average…

  18. Salaries of Head Coaches Are Rising, Survey Shows.

    ERIC Educational Resources Information Center

    Naughton, Jim

    1998-01-01

    Salaries of head coaches in college sports are rising, but a large salary gap remains between coaches of men's and women's teams. In a national ranking of institutions by salary averages, men's coaches at the median institution made 43% more than women's coaches. Some institutions provide more salary equity than others. The Justice Department is…

  19. Effects of a rise in base level on graded streams

    SciTech Connect

    Dickfoss, P.V. . Geology Dept.)

    1994-04-01

    What changes take place in a longitudinal river profile due to a rise in base level would seem to be a fundamental question in geomorphology, however, little has been accomplished toward answering this question, and the prevailing views are contradictory. Most authors say that a river will adjust its entire profile in response to a rise in base level. This misconception appears to have started in Elmo G. Harris' 1901 article, Effects of Dams and Like Obstructions in Silt-bearing Streams. The hypothesis became popular after publication of J. Hoover Mackin's classic 1948 paper, Concept of the Graded River. In the section Rise of Base Level'' Mackin explained that ''...the only generalization that can be made is that the new profile will be everywhere adjusted to the new prevailing conditions.'' Although Mackin's idea was a conceptual one, the concept has subsequently been taken literally. Contrary to this perception, the small amount of work that has been completed shows rivers will adjust their profiles only a short distance upstream from reservoir level. This may be due to the adjustment becoming infinitesimally small upstream and grading into the original profile so that the adjustment upstream is negligible. Unfortunately the misconception of stream aggradation in response to a rise in base level has prevailed for over 90 years and is widespread in the literature. Many textbooks, both introductory and advanced, from 1971 to the present, and some of the leading names in geomorphology have accepted the misconception without question.

  20. The rise (and fall?) of parental vaccine hesitancy

    PubMed Central

    Gowda, Charitha; Dempsey, Amanda F

    2013-01-01

    Parental vaccine hesitancy is a growing problem affecting the health of children and the larger population. This article describes the evolution of the vaccine hesitancy movement and the individual, vaccine-specific and societal factors contributing to this phenomenon. In addition, potential strategies to mitigate the rising tide of parent vaccine reluctance and refusal are discussed. PMID:23744504

  1. STD rates began rising long ago, say researchers.

    PubMed

    2003-08-01

    Although recent increases in some sexually transmitted diseases have health officials worried about a rise in new HIV cases, a new study shows that risk behavior among HIV-positive people has been a problem for at least a decade. The results show a need for greater emphasis on 'prevention among positives,' says a researcher.

  2. Effect of coring conditions on temperature rise in bone.

    PubMed

    Islam, Md Monirul; Wang, Xiaodu

    2017-01-01

    Coring is a surgical procedure in bone biopsy retrieval and dental/orthopaedic procedures, which may cause thermal damage to bone tissues adjacent to the coring zone. This study was performed to determine the temperature rise in bone by coring using a semi-empirical thermocouple approach. Concurrently, a custom-made dynamometer was used to measure the cutting and thrust forces during coring bovine cortical bone samples. The experimental results indicated that the cutting force, cutting speed, and depth of cut significantly affect the temperature rise in the cutting zone during coring process. In addition, acute temperature rises in the cutting zone occurred when the cutting speed exceeded threshold levels. The limited capacity of heat dissipation during coring is most likely responsible for such a sharp temperature rise with increasing cutting speed. Moreover, it was observed that the maximum size of potential thermal damage zone could reach to 3.0 mm in depth from the surface of the coring hole, assuming that thermal damage would occur when the temperature is greater than 47°C. Thus, proper cutting conditions need to be selected to avoid the potential thermal damage to bone during the coring procedures.

  3. Colleges' Debt Is Fed by Rising Bond Rates

    ERIC Educational Resources Information Center

    Wolverton, Brad

    2008-01-01

    Dozens of colleges and universities, including some of the country's wealthiest institutions, are facing a sharp rise in interest payments on a whopping mound of debt. About a third of the nearly 300 private institutions rated by Moody's Investors Service are financing more than half their debt with variable-rate bonds, some of whose rates have…

  4. Michael Young's "The Rise of the Meritocracy": A Philosophical Critique

    ERIC Educational Resources Information Center

    Allen, Ansgar

    2011-01-01

    This paper examines Michael Young's 1958 dystopia, "The Rise of the Meritocracy". In this book, the word "meritocracy" was coined and used in a pejorative sense. Today, however, meritocracy represents a positive ideal against which we measure the justice of our institutions. This paper argues that, when read in the twenty-first century, Young's…

  5. Rising Opportunities in the Field of Engineering: Implications for Counselors

    ERIC Educational Resources Information Center

    Smith, Gloria S.; And Others

    1973-01-01

    In the Endicott Report a survey of businesses and industries indicated a lack of Black engineers, accountants, and graduates in business administration. The report indicated that competition is keen for Blacks talented in these fields. With the rising opportunities for Black talent, a clarification of needs and services must be projected to those…

  6. Suppressing the Morning Rise in Cortisol Impairs Free Recall

    ERIC Educational Resources Information Center

    Rimmele, Ulrike; Meier, Flurina; Lange, Tanja; Born, Jan

    2010-01-01

    Elevated glucocorticoid levels impair memory retrieval. We investigated whether retrieval under naturally elevated glucocorticoid levels, i.e., during the morning rise in cortisol can be improved by suppressing cortisol. In a crossover study 16 men retrieved emotional and neutral texts and pictures (learned 3 d earlier) 30 min after morning…

  7. The Secular Rise in IQ: Giving Heterosis a Closer Look

    ERIC Educational Resources Information Center

    Mingroni, Michael A.

    2004-01-01

    Although most discussions today start from the assumption that the secular rise in IQ must be environmental in origin, three reasons warrant giving the genetic phenomenon heterosis a closer look as a potential cause. First, it easily accounts for both the high heritability and low shared environmental effects seen in IQ, findings that are…

  8. The Loss of Jobs and the Rise of the Underclass.

    ERIC Educational Resources Information Center

    Hill, Norman

    1988-01-01

    William Julius Wilson's "The Truly Disadvantaged" blames the rise in the Black urban underclass on the rapid, systemic, and structural changes in the economy in the 1970s, which left Black unemployment at a spectacularly high rate. His insights should be acknowledged and his recommendations heeded. (BJV)

  9. 11. Buttress rising above stream bed elevation. Concrete mixing plant ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Buttress rising above stream bed elevation. Concrete mixing plant is at right, west tower and placement tower boom are visible. Photographer unknown, November 24, 1926. Source: Ralph Pleasant. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  10. Thermodynamics of Capillary Rise: Why Is the Meniscus Curved?

    ERIC Educational Resources Information Center

    Henriksson, Ulf; Eriksson, Jan Christer

    2004-01-01

    The thermodynamics of capillary rise is explained as the gravitational elevation of the whole column of liquid caused by the positive connection between the liquid, and the solid wall of the capillary tube. The curvature of the meniscus is ascribed to the maintenance of a physiochemical balance throughout the gravitational column of liquid.

  11. One per cent rise in budget not enough.

    PubMed

    Gray, J

    1994-12-07

    The government fulfilled its election pledge to increase spending on health again next year, but there were fears that the 1 per cent rise announced in last week's budget is not enough to keep pace with inflation and growing demands on the service.

  12. Rising above the Gathering Storm, Revisited: Rapidly Approaching Category 5

    ERIC Educational Resources Information Center

    National Academies Press, 2010

    2010-01-01

    In the face of so many daunting near-term challenges, U.S. government and industry are letting the crucial strategic issues of U.S. competitiveness slip below the surface. Five years ago, the National Academies prepared "Rising Above the Gathering Storm," a book that cautioned: "Without a renewed effort to bolster the foundations of…

  13. The Rising Cost of Higher Education. APPA Thought Leaders 2013

    ERIC Educational Resources Information Center

    APPA: Association of Higher Education Facilities Officers, 2013

    2013-01-01

    The 2013 Thought Leaders Symposium, sponsored in part by DTZ, a UGL company, and Jacobs, focused on the topic of the rising cost of higher education. More than three dozen higher education leaders--including presidents, provosts, business officers, consultants, association executives, and facilities professionals--participated in a facilitated…

  14. RETENTION BASIN. ERECTING REINFORCING STEEL FOR CONCRETE DECK. STACK RISES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    RETENTION BASIN. ERECTING REINFORCING STEEL FOR CONCRETE DECK. STACK RISES AT TOP LEFT. CAMERA FACES WEST. INL NEGATIVE NO. 2581. Unknown Photographer, 6/18/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  15. Whither Opportunity? Rising Inequality, Schools, and Children's Life Chances

    ERIC Educational Resources Information Center

    Duncan, Greg J., Ed.; Murnane, Richard, Ed.

    2011-01-01

    As the incomes of affluent and poor families have diverged over the past three decades, so too has the educational performance of their children. But how exactly do the forces of rising inequality affect the educational attainment and life chances of low-income children? In "Whither Opportunity?" a distinguished team of economists,…

  16. RISING ATMOSPHERIC CO2 AND CARBON SEQUESTRATION IN FORESTS

    EPA Science Inventory

    Rising CO2 concentrations in the Earth's atmosphere could alter Earth's climate system, but it is thought that higher concentrations may improve plant growth by way of the fertilization effect. Forests, an important part of the Earth's carbon cycle, are postulated to sequester a...

  17. Rising Cost of Gasoline Pinches Students at Rural Community Colleges

    ERIC Educational Resources Information Center

    Sander, Libby

    2008-01-01

    Aware of the increasing burden of fuel costs on their students, administrators of rural community colleges are looking for ways to help students stay on track with their studies even as their monthly transportation bills rise. Two common tactics are increasing the number of online courses and offering block scheduling that allows students to pack…

  18. Rise in water vapor due to anthropogenic warming

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-08-01

    The rise in atmospheric water vapor—a significant greenhouse gas—over the past 30 years can be tied to human activities, according to a new paper (doi:10.1073/pnas.1409659111) published in the Proceedings of the National Academy of Sciences of the United States of America.

  19. Biogeochemical Modeling of the Second Rise of Atmospheric Oxygen

    NASA Astrophysics Data System (ADS)

    Smith, M.; Catling, D. C.; Claire, M.

    2014-12-01

    The second rise of atmospheric oxygen (~600 Ma) marked an increase of atmospheric pO2 from a poorly constrained value of 0.1% < pO2 < 10% of present atmospheric level (PAL) in the early and mid Proterozoic to >10%PAL1. The event is important because it ushered in the modern era of animal life. To understand the evolution of Earth's habitability, it is therefore key to understand the cause of this 2nd rise. Here, we quantitatively examine possible causes for the 2nd rise of oxygen. We use a biogeochemical box model2 originally developed to calculate the oxygen evolution before and after the 1st rise of oxygen (~2.4 Ga). The Claire et al. (2006) model calculates the evolution of atmospheric oxygen and methane given production and loss fluxes associated with the oxygen, carbon, and iron cycles. Because the model was unable to drive pO2 to end-Proterozoic levels, the authors suggested that another buffer, such as sulfur, is needed to explain the 2nd rise of oxygen. The sulfur and oxygen cycles are tied through various biogeochemical interactions; therefore, once sulfur (as sulfate) began to accumulate in Proterozoic oceans, it likely began to heavily influence the oxygen cycle. We have added a sulfur biogeochemical cycle to this model, enabling exploration of mechanisms that buffer pO2 at intermediate levels in the Proterozoic and fail to do so in the Phanerozoic. Preliminary results show evolution of oxygen and methane that are consistent with geologic proxies. However, the model-generated 2nd rise of oxygen is dependent upon sulfur fluxes that have uncertain magnitudes, so we will present the sensitivity of our results to model assumptions while constraining scenarios for the 2nd rise of atmospheric O2. In the future, we will also integrate isotopic fractionation effects, which will allow comparison with isotopic data from sedimentary sulfides, carbonates, and organic carbon. 1Canfield, C., 2014, Treatise on Geochemistry, 197 2Claire, M.W., et al., 2006, Geobiology

  20. Experimental investigation of dynamic contact angle and capillary rise in tubes with circular and noncircular cross sections.

    PubMed

    Heshmati, Mohammad; Piri, Mohammad

    2014-12-02

    An extensive experimental study of the kinetics of capillary rise in borosilicate glass tubes of different sizes and cross-sectional shapes using various fluid systems and tube tilt angles is presented. The investigation is focused on the direct measurement of dynamic contact angle and its variation with the velocity of the moving meniscus (or capillary number) in capillary rise experiments. We investigated this relationship for different invading fluid densities, viscosities, and surface tensions. For circular tubes, the measured dynamic contact angles were used to obtain rise-versus-time values that agree more closely with their experimental counterparts (also reported in this study) than those predicted by Washburn equation using a fixed value of contact angle. We study the predictive capabilities of four empirical correlations available in the literature for velocity-dependence of dynamic contact angle by comparing their predicted trends against our measured values. We also present measurements of rise in noncircular capillary tubes where rapid advancement of arc menisci in the corners ahead of main terminal meniscus impacts the dynamics of rise. Using the extensive set of experimental data generated in this study, a new general empirical trend is presented for variation of normalized rise with dynamic contact angle that can be used in, for instance, dynamic pore-scale models of flow in porous media to predict multiphase flow behavior.

  1. Keep up or drown: adjustment of western Pacific coral reefs to sea-level rise in the 21st century.

    PubMed

    van Woesik, R; Golbuu, Y; Roff, G

    2015-07-01

    Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are 'keeping up' with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6-8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially 'keep up' with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low-mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m(-2)), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century.

  2. Neogene-Quaternary depositional history of the eastern US continental rise seaward of the Washington-Norfolk Canyon systems

    SciTech Connect

    Locker, S.D.; Laine, E.P.

    1985-01-01

    High quality, digitally recorded and processed, water gun and air gun seismic reflection data collected seaward of the present position of the Washington-Norfolk canyon systems reveals new information on the development of the continental rise. This includes insight into the depositional history of the Washington-Norfolk fan system and the relative importance of gravity flow depositional processes versus abyssal bottom current reworking during rise development. Three major post-Horizon A/sup u/ accretionary sequences describe major changes in depositional processes and history within the region. Accretionary sequence I (early to middle Miocene) is characterized by the initial development of a depositional bulge seaward of the Washington-Norfolk canyon systems which is modified by bottom currents on the lower-most rise to form a proto-Hatteras Outer Ridge. The predominance of chaotic and hummocky seismic facies suggests widespread reworking by abyssal bottom currents. Accretionary sequence II (middle Miocene to late Pliocene) in this area is characterized by sediment waves (lower rise) and smooth, southward dipping, parallel reflectors associated with a thick central rise drift(.) deposit off the Hudson system to the North. Washington-Norfolk fan development appears less important during this time. Bottom currents are active, but more depositional in nature than during accretionary sequence I. Accretionary sequence III (late Pliocene to Present) is marked by gravity flow processes and distinct development of the Washington-Norfolk fan on the central rise.

  3. Rising tides or rising stars?: Dynamics of shared attention on Twitter during media events.

    PubMed

    Lin, Yu-Ru; Keegan, Brian; Margolin, Drew; Lazer, David

    2014-01-01

    "Media events" generate conditions of shared attention as many users simultaneously tune in with the dual screens of broadcast and social media to view and participate. We examine how collective patterns of user behavior under conditions of shared attention are distinct from other "bursts" of activity like breaking news events. Using 290 million tweets from a panel of 193,532 politically active Twitter users, we compare features of their behavior during eight major events during the 2012 U.S. presidential election to examine how patterns of social media use change during these media events compared to "typical" time and whether these changes are attributable to shifts in the behavior of the population as a whole or shifts from particular segments such as elites. Compared to baseline time periods, our findings reveal that media events not only generate large volumes of tweets, but they are also associated with (1) substantial declines in interpersonal communication, (2) more highly concentrated attention by replying to and retweeting particular users, and (3) elite users predominantly benefiting from this attention. These findings empirically demonstrate how bursts of activity on Twitter during media events significantly alter underlying social processes of interpersonal communication and social interaction. Because the behavior of large populations within socio-technical systems can change so dramatically, our findings suggest the need for further research about how social media responses to media events can be used to support collective sensemaking, to promote informed deliberation, and to remain resilient in the face of misinformation.

  4. Temperature rise, sea level rise and increased radiative forcing - an application of cointegration methods

    NASA Astrophysics Data System (ADS)

    Schmith, Torben; Thejll, Peter; Johansen, Søren

    2016-04-01

    We analyse the statistical relationship between changes in global temperature, global steric sea level and radiative forcing in order to reveal causal relationships. There are in this, however, potential pitfalls due to the trending nature of the time series. We therefore apply a statistical method called cointegration analysis, originating from the field of econometrics, which is able to correctly handle the analysis of series with trends and other long-range dependencies. Further, we find a relationship between steric sea level and temperature and find that temperature causally depends on the steric sea level, which can be understood as a consequence of the large heat capacity of the ocean. This result is obtained both when analyzing observed data and data from a CMIP5 historical model run. Finally, we find that in the data from the historical run, the steric sea level, in turn, is driven by the external forcing. Finally, we demonstrate that combining these two results can lead to a novel estimate of radiative forcing back in time based on observations.

  5. The Rise and Fall of the Luminiferous Aether: Are We Poised for Another Rise?

    NASA Astrophysics Data System (ADS)

    Christov, Christo

    2008-10-01

    If there is a wave, something material should be ``waving.'' This notion led in to luminiferous medium (aether). Cauchy explained Fresnel's diffraction experiment as the shear waves of his elastic aether. Maxwell added the ``displacement current'' which resulted into a characteristic speed of propagation identified as the speed of light. In the late 19th century the investigations were predominantly aimed at discovering the medium described by Maxwell equations, but none was found. The nil result of Michelson and Morley experiment was thought to disprove the existence of the aether. The wave equation of electrodynamics was made invariant by changing the time in the moving frame: so-called Lorentz Transformation (LT) which set a new paradigm. LT, however, is not valid in accelerating or deforming coordinate frames. Its consistent application leads to paradoxes. Recently, a truly invariant model of space as a material continuum (metacontinuum) has been proposed whose corollary are the Maxwell equations. The charges are shown to undergo Lorentz contraction as moving patterns. Accounting for the motion of the emitting atom relative to the metacontinuum, explains the Ives--Stilwell experiment without time dilation. Thus, the stage is set for a new look into the absolute medium.

  6. Delaying future sea-level rise by storing water in Antarctica

    NASA Astrophysics Data System (ADS)

    Frieler, K.; Mengel, M.; Levermann, A.

    2016-03-01

    Even if greenhouse gas emissions were stopped today, sea level would continue to rise for centuries, with the long-term sea-level commitment of a 2 °C warmer world significantly exceeding 2 m. In view of the potential implications for coastal populations and ecosystems worldwide, we investigate, from an ice-dynamic perspective, the possibility of delaying sea-level rise by pumping ocean water onto the surface of the Antarctic ice sheet. We find that due to wave propagation ice is discharged much faster back into the ocean than would be expected from a pure advection with surface velocities. The delay time depends strongly on the distance from the coastline at which the additional mass is placed and less strongly on the rate of sea-level rise that is mitigated. A millennium-scale storage of at least 80 % of the additional ice requires placing it at a distance of at least 700 km from the coastline. The pumping energy required to elevate the potential energy of ocean water to mitigate the currently observed 3 mm yr-1 will exceed 7 % of the current global primary energy supply. At the same time, the approach offers a comprehensive protection for entire coastlines particularly including regions that cannot be protected by dikes.

  7. Delaying future sea-level rise by storing water on Antarctica

    NASA Astrophysics Data System (ADS)

    Frieler, K.; Mengel, M.; Levermann, A.

    2015-10-01

    Even if greenhouse gas emissions were stopped today sea level would continue to rise for centuries with the long-term sea-level commitment of a two-degree-warmer world significantly exceeding 2 m. In view of the potential implications for coastal populations and ecosystems worldwide we investigate, from an ice-dynamic perspective, the possibility to delay sea-level rise by pumping ocean water onto the surface of the Antarctic Ice Sheet. We find that due to wave propagation ice is discharged much faster back into the ocean than would be expected from a pure advection with surface velocities. The delay time depends strongly on the distance from the coastline at which the additional mass is placed and less strongly on the rate of sea-level rise that is mitigated. A millennium-scale storage of at least 80 % of the additional ice requires placing it at a distance of at least 700 km from the coast line. The pumping energy required to elevate the potential energy of ocean water to mitigate the currently observed 3 mm yr-1 will exceed 7 % of the current global primary energy supply. At the same time the approach may be the only way to protect entire coastlines or specific regions that cannot be protected by dikes.

  8. Pharmacology of rising oral doses of 5-hydroxytryptophan with carbidopa.

    PubMed

    Smarius, L J C A; Jacobs, G E; Hoeberechts-Lefrandt, D H M; de Kam, M L; van der Post, J P; de Rijk, R; van Pelt, J; Schoemaker, R C; Zitman, F G; van Gerven, J M A; Gijsman, H J

    2008-06-01

    5-hydroxytryptophan (5-HTP) is a direct 5-hydroxytryptamine (5-HT) precursor used to assess central serotonergic function. Its use has been limited by a narrow window between neuroendocrine changes and side effects, and variable kinetics related to inconsistent administration modes. By combining 5-HTP with carbidopa (CBD), increased bioavailability for brain penetration and decreased peripheral side effects would be expected, due to reduced peripheral decarboxylation of 5-HTP to 5-HT. A double-blind, placebo-controlled, single rising dose, four-way crossover trial with placebo randomisation was performed in 15 healthy male volunteers to investigate the neuroendocrine dose-response relationship at various 5-HTP levels; the tolerability and subjective effects of oral 5-HTP at 100, 200 and 300 mg combined with CBD and the pharmacokinetic properties of the 5-HTP/CBD-challenge. Dose-dependent increases in average cortisol concentrations were observed. Mean response (area-under-the-curve) over the first 4 hours (SD): 172.0 nmol/L (22.3) for placebo, 258.3 nmol/L (72.6) for 100 mg, 328.47 nmol/L (84.6) for 200 mg and 387.3 nmol/L (82.4) for 300 mg 5-HTP. Similar dose-dependent increases for prolactin were seen while adreno-corticotrophic hormone response was more variable. 5-HTP kinetics were adequately described using a one-compartment model with first-order absorption and a lag time (mean oral clearance 28 L/h interindividual coefficient of variation 31%). Nausea and vomiting occurred dose-dependently as most frequent side effects, resulting in dose-related dropout of 6.6% at 100 mg and 45.5% at 300 mg 5-HTP. Orally administered 5-HTP combined with CBD is an effective serotonergic challenge test, exhibiting dose-related plasma concentrations and neuroendocrine responsiveness. Frequent occurrence of nausea and vomiting limits the applicability of this challenge at 5-HTP doses above 100 mg.

  9. A Zn isotope perspective on the rise of continents.

    PubMed

    Pons, M-L; Fujii, T; Rosing, M; Quitté, G; Télouk, P; Albarède, F

    2013-05-01

    Zinc isotope abundances are fairly constant in igneous rocks and shales and are left unfractionated by hydrothermal processes at pH < 5.5. For that reason, Zn isotopes in sediments can be used to trace the changing chemistry of the hydrosphere. Here, we report Zn isotope compositions in Fe oxides from banded iron formations (BIFs) and iron formations of different ages. Zinc from early Archean samples is isotopically indistinguishable from the igneous average (δ(66) Zn ~0.3‰). At 2.9-2.7 Ga, δ(66) Zn becomes isotopically light (δ(66) Zn < 0‰) and then bounces back to values >1‰ during the ~2.35 Ga Great Oxygenation Event. By 1.8 Ga, BIF δ(66) Zn has settled to the modern value of FeMn nodules and encrustations (~0.9‰). The Zn cycle is largely controlled by two different mechanisms: Zn makes strong complexes with phosphates, and phosphates in turn are strongly adsorbed by Fe hydroxides. We therefore review the evidence that the surface geochemical cycles of Zn and P are closely related. The Zn isotope record echoes Sr isotope evidence, suggesting that erosion starts with the very large continental masses appearing at ~2.7 Ga. The lack of Zn fractionation in pre-2.9 Ga BIFs is argued to reflect the paucity of permanent subaerial continental exposure and consequently the insignificant phosphate input to the oceans and the small output of biochemical sediments. We link the early decline of δ(66) Zn between 3.0 and 2.7 Ga with the low solubility of phosphate in alkaline groundwater. The development of photosynthetic activity at the surface of the newly exposed continents increased the oxygen level in the atmosphere, which in turn triggered acid drainage and stepped up P dissolution and liberation of heavy Zn into the runoff. Zinc isotopes provide a new perspective on the rise of continents, the volume of carbonates on continents, changing weathering conditions, and compositions of the ocean through time.

  10. A decade of sea level rise slowed by climate-driven hydrology.

    PubMed

    Reager, J T; Gardner, A S; Famiglietti, J S; Wiese, D N; Eicker, A; Lo, M-H

    2016-02-12

    Climate-driven changes in land water storage and their contributions to sea level rise have been absent from Intergovernmental Panel on Climate Change sea level budgets owing to observational challenges. Recent advances in satellite measurement of time-variable gravity combined with reconciled global glacier loss estimates enable a disaggregation of continental land mass changes and a quantification of this term. We found that between 2002 and 2014, climate variability resulted in an additional 3200 ± 900 gigatons of water being stored on land. This gain partially offset water losses from ice sheets, glaciers, and groundwater pumping, slowing the rate of sea level rise by 0.71 ± 0.20 millimeters per year. These findings highlight the importance of climate-driven changes in hydrology when assigning attribution to decadal changes in sea level.

  11. Rising pressure: hospital emergency departments as barometers of the health care system.

    PubMed

    O'Malley, Ann S; Gerland, Anneliese M; Pham, Hoangmai H; Berenson, Robert A

    2005-11-01

    Pressures--ranging from persuading specialists to provide on-call coverage to dealing with growing numbers of patients with serious mental illness--are building in already-crowded hospital emergency departments (EDs) across the country, according to findings from the Center for Studying Health System Change's (HSC) 2005 site visits to 12 nationally representative communities. As the number of ED visits rises significantly faster than population growth, many hospitals are expanding emergency department capacity. At the same time, hospitals face an ongoing nursing shortage, contributing to tight inpatient capacity that in turn hinders admitting ED patients. In their role as hospitals' "front door" for attracting insured inpatient admissions, emergency departments also increasingly are expected to help hospitals compete for insured patients while still meeting obligations to provide emergency care to all-comers under federal law. Failure to address these growing pressures may compromise access to emergency care for patients and spur already rapidly rising health care costs.

  12. Sr isotopic chemostratigraphy of Precambrian carbonate rocks in the Amderma Rise, Pai-Khoi Ridge

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. B.; Starikova, E. V.; Maslov, A. V.; Konstantinova, G. V.

    2016-08-01

    The Sr and C isotopic compositions of Precambrian carbonate rocks are determined for Amderma Rise, in the northeastern margin of Pai-Khoi Ridge. Based on the Sr isotopic chemostratigraphy, it is established for the first time that the Amderma Formation is referred to the Early Vendian, while the Morozovsk Formation is Late Riphean in age. This conclusion along with detailed mapping proves that the Precambrian "section" of the Amderma Rise is a series of tectonic plates combined in a nonchronostratigraphic order. Volcanic and sedimentary rocks of the Morozovsk and Sokolninsk formations make up the allochthon proper, while carbonate rocks of the Amderma Formation make up the para-autochthon. The high values of δ13C (up to +9.5‰) identified in limestones of both formations suggest a considerable distance of the Pai-Khoi paleobasin from the passive margin of the Baltic Region upon facies similarity to the Laurentia active margins.

  13. The Son-Rise Program intervention for autism: prerequisites for evaluation.

    PubMed

    Williams, K R

    2006-01-01

    With increasing availability of interventions for children with autism, it is important that these are backed by rigorous evaluation data that have high levels of ecological validity. To achieve this, a key prerequisite for any evaluation is to gather data on typical consumers and typical implementation patterns of the intervention. This study collected such data longitudinally in relation to the Son-Rise Program, a home-based parent-run intervention for autism. Questionnaires and interview data on family demographics, implementation patterns, and perceived treatment fidelity were gathered three times over the course of a year from families who had attended a Son-Rise initial training course. Although it proved possible to produce a profile of intervention use, findings indicated that the programme is not always implemented as it is typically described in the literature. The study also highlighted methodological challenges likely to be encountered in any future evaluation of this and similar interventions for autism.

  14. Rising Tides or Rising Stars?: Dynamics of Shared Attention on Twitter during Media Events

    PubMed Central

    Lin, Yu-Ru; Keegan, Brian; Margolin, Drew; Lazer, David

    2014-01-01

    “Media events” generate conditions of shared attention as many users simultaneously tune in with the dual screens of broadcast and social media to view and participate. We examine how collective patterns of user behavior under conditions of shared attention are distinct from other “bursts” of activity like breaking news events. Using 290 million tweets from a panel of 193,532 politically active Twitter users, we compare features of their behavior during eight major events during the 2012 U.S. presidential election to examine how patterns of social media use change during these media events compared to “typical” time and whether these changes are attributable to shifts in the behavior of the population as a whole or shifts from particular segments such as elites. Compared to baseline time periods, our findings reveal that media events not only generate large volumes of tweets, but they are also associated with (1) substantial declines in interpersonal communication, (2) more highly concentrated attention by replying to and retweeting particular users, and (3) elite users predominantly benefiting from this attention. These findings empirically demonstrate how bursts of activity on Twitter during media events significantly alter underlying social processes of interpersonal communication and social interaction. Because the behavior of large populations within socio-technical systems can change so dramatically, our findings suggest the need for further research about how social media responses to media events can be used to support collective sensemaking, to promote informed deliberation, and to remain resilient in the face of misinformation. PMID:24854030

  15. Efficacy of geoengineering to limit 21st century sea-level rise.

    PubMed

    Moore, J C; Jevrejeva, S; Grinsted, A

    2010-09-07

    Geoengineering has been proposed as a feasible way of mitigating anthropogenic climate change, especially increasing global temperatures in the 21st century. The two main geoengineering options are limiting incoming solar radiation, or modifying the carbon cycle. Here we examine the impact of five geoengineering approaches on sea level; SO(2) aerosol injection into the stratosphere, mirrors in space, afforestation, biochar, and bioenergy with carbon sequestration. Sea level responds mainly at centennial time scales to temperature change, and has been largely driven by anthropogenic forcing since 1850. Making use a model of sea-level rise as a function of time-varying climate forcing factors (solar radiation, volcanism, and greenhouse gas emissions) we find that sea-level rise by 2100 will likely be 30 cm higher than 2000 levels despite all but the most aggressive geoengineering under all except the most stringent greenhouse gas emissions scenarios. The least risky and most desirable way of limiting sea-level rise is bioenergy with carbon sequestration. However aerosol injection or a space mirror system reducing insolation at an accelerating rate of 1 W m(-2) per decade from now to 2100 could limit or reduce sea levels. Aerosol injection delivering a constant 4 W m(-2) reduction in radiative forcing (similar to a 1991 Pinatubo eruption every 18 months) could delay sea-level rise by 40-80 years. Aerosol injection appears to fail cost-benefit analysis unless it can be maintained continuously, and damage caused by the climate response to the aerosols is less than about 0.6% Global World Product.

  16. Efficacy of geoengineering to limit 21st century sea-level rise

    PubMed Central

    Moore, J. C.; Jevrejeva, S.; Grinsted, A.

    2010-01-01

    Geoengineering has been proposed as a feasible way of mitigating anthropogenic climate change, especially increasing global temperatures in the 21st century. The two main geoengineering options are limiting incoming solar radiation, or modifying the carbon cycle. Here we examine the impact of five geoengineering approaches on sea level; SO2 aerosol injection into the stratosphere, mirrors in space, afforestation, biochar, and bioenergy with carbon sequestration. Sea level responds mainly at centennial time scales to temperature change, and has been largely driven by anthropogenic forcing since 1850. Making use a model of sea-level rise as a function of time-varying climate forcing factors (solar radiation, volcanism, and greenhouse gas emissions) we find that sea-level rise by 2100 will likely be 30 cm higher than 2000 levels despite all but the most aggressive geoengineering under all except the most stringent greenhouse gas emissions scenarios. The least risky and most desirable way of limiting sea-level rise is bioenergy with carbon sequestration. However aerosol injection or a space mirror system reducing insolation at an accelerating rate of 1 W m-2 per decade from now to 2100 could limit or reduce sea levels. Aerosol injection delivering a constant 4 W m-2 reduction in radiative forcing (similar to a 1991 Pinatubo eruption every 18 months) could delay sea-level rise by 40–80 years. Aerosol injection appears to fail cost-benefit analysis unless it can be maintained continuously, and damage caused by the climate response to the aerosols is less than about 0.6% Global World Product. PMID:20798055

  17. A miniature real-time volumetric ultrasound imaging system

    NASA Astrophysics Data System (ADS)

    Wygant, Ira O.; Yeh, David T.; Zhuang, Xuefeng; Nikoozadeh, Amin; Oralkan, Omer; Ergun, Arif S.; Karaman, Mustafa; Khuri-Yakub, Butrus T.

    2005-04-01

    Progress made in the development of a miniature real-time volumetric ultrasound imaging system is presented. This system is targeted for use in a 5-mm endoscopic channel and will provide real-time, 30-mm deep, volumetric images. It is being developed as a clinically useful device, to demonstrate a means of integrating the front-end electronics with the transducer array, and to demonstrate the advantages of the capacitive micromachined ultrasonic transducer (CMUT) technology for medical imaging. Presented here is the progress made towards the initial implementation of this system, which is based on a two-dimensional, 16x16 CMUT array. Each CMUT element is 250 um by 250 um and has a 5 MHz center frequency. The elements are connected to bond pads on the back side of the array with 400-um long through-wafer interconnects. The transducer array is flip-chip bonded to a custom-designed integrated circuit that comprises the front-end electronics. The result is that each transducer element is connected to a dedicated pulser and low-noise preamplifier. The pulser generates 25-V, 100-ns wide, unipolar pulses. The preamplifier has an approximate transimpedance gain of 500 kOhm and 3-dB bandwidth of 10 MHz. In the first implementation of the system, one element at a time can be selected for transmit and receive and thus synthetic aperture images can be generated. In future implementations, 16 channels will be active at a given time. These channels will connect to an FPGA-based data acquisition system for real-time image reconstruction.

  18. Evidence for a substantial West Antarctic ice sheet contribution to meltwater pulses and abrupt global sea level rise

    NASA Astrophysics Data System (ADS)

    Fogwill, C. J.; Turney, C. S.; Golledge, N. R.; Etheridge, D. M.; Rubino, M.; Thornton, D.; Woodward, J.; Winter, K.; van Ommen, T. D.; Moy, A. D.; Curran, M. A.; Rootes, C.; Rivera, A.; Millman, H.

    2015-12-01

    During the last deglaciation (21,000 to 7,000years ago) global sea level rise was punctuated by several abrupt meltwater spikes triggered by the retreat of ice sheets and glaciers world-wide. However, the debate regarding the relative timing, geographical source and the physical mechanisms driving these rapid increases in sea level has catalyzed debate critical to predicting future sea level rise and climate. Here we present a unique record of West Antarctic Ice Sheet elevation change derived from the Patriot Hills blue ice area, located close to the modern day grounding line of the Institute Ice Stream in the Weddell Sea Embayment. Combined isotopic signatures and gas volume analysis from the ice allows us to develop a record of local ice sheet palaeo-altitude that is assessed against independent regional high-resolution ice sheet modeling studies, allowing us to demonstrate that past ice sheet elevations across this sector of the WSE were considerably higher than those suggested by current terrestrial reconstructions. We argue that ice in the WSE had a significant influence on both pre and post LGM sea level rise including MWP-1A (~14.6 ka) and during MWP-1B (11.7-11.6 ka), reconciling past sea level rise and demonstrating for the first time that this sector of the WAIS made a significant and direct contribution to post LGM sea level rise.

  19. Interactions between sea-level rise and wave exposure on reef island dynamics in the Solomon Islands

    NASA Astrophysics Data System (ADS)

    Albert, Simon; Leon, Javier X.; Grinham, Alistair R.; Church, John A.; Gibbes, Badin R.; Woodroffe, Colin D.

    2016-05-01

    Low-lying reef islands in the Solomon Islands provide a valuable window into the future impacts of global sea-level rise. Sea-level rise has been predicted to cause widespread erosion and inundation of low-lying atolls in the central Pacific. However, the limited research on reef islands in the western Pacific indicates the majority of shoreline changes and inundation to date result from extreme events, seawalls and inappropriate development rather than sea-level rise alone. Here, we present the first analysis of coastal dynamics from a sea-level rise hotspot in the Solomon Islands. Using time series aerial and satellite imagery from 1947 to 2014 of 33 islands, along with historical insight from local knowledge, we have identified five vegetated reef islands that have vanished over this time period and a further six islands experiencing severe shoreline recession. Shoreline recession at two sites has destroyed villages that have existed since at least 1935, leading to community relocations. Rates of shoreline recession are substantially higher in areas exposed to high wave energy, indicating a synergistic interaction between sea-level rise and waves. Understanding these local factors that increase the susceptibility of islands to coastal erosion is critical to guide adaptation responses for these remote Pacific communities.

  20. Supercontinent cyclicity and the rise and fall of atmospheric oxygen (Invited)

    NASA Astrophysics Data System (ADS)

    Van Kranendonk, M. J.; Kirkland, C. L.

    2013-12-01

    Recent work on Hf isotopes in zircon has suggested that the apparent peaks and troughs in continental crust formation through the Precambrian, identified by zircon U-Pb age data and interpreted as reflecting the supercontinent cycle, may be a preservational artefact. However, an evaluation of time constrained analyses of oxygen and Hf isotopes in zircon grains and incompatible element (Zr, Th) concentrations in magmatic rocks to test for variations in the degree of crustal recycling through geological time, shows that the supercontinent cycle was operative throughout the Precambrian, from the onset of modern-style subduction at c. 3.2 Ga. This finding is highly significant for better understanding the changes in composition of the atmosphere/hydrosphere through time - in particular the rise of atmospheric oxygen - and also to the evolution of the biosphere. When placed in context with geological and geobiological events across the extended Archean-Proterozoic transition, the rise of atmospheric oxygen (at 2.42-2.22 Ga) is seen to result from a combination of: a) the near-complete cessation of plate tectonics and associated volcanic-derived gassing (CO2, H2S, SO2) of the atmosphere during this interval; b) drawdown of the earlier greenhouse atmosphere by weathering of extensive greenstones newly erupted during the Late Archean Superevent (2.8-2.63 Ga formation of Supercontinent(s) Superia/Sclavia) and newly exposed during continental emergence at the close of the Archean. This combination of events led to atmospheric cooling, resulting in widespread (global?) glaciations. The buildup of atmospheric oxygen led to development/flourishing of eukaryotes. Restarting of the global magmatic system at 2.22-1.8 Ga during the leadup to Supercontinent Nuna, saw the return of nearly Archean-like conditions, with a high-pCO2 atmosphere, recurrence of granite-greenstone type crust, and the reappearance of iron-formations. Widespread subduction during supercontinent formation

  1. Exploring the mechanisms of rising bubbles in marine biofouling prevention

    NASA Astrophysics Data System (ADS)

    Menesses, Mark; Belden, Jesse; Dickenson, Natasha; Bird, James

    2015-11-01

    Fluid motion, such as flow past a ship, is known to inhibit the growth of marine biofouling. Bubbles rising along a submerged structure also exhibit this behavior, which is typically attributed to buoyancy induced flow. However, the bubble interface may also have a direct influence on inhibiting growth that is independent of the surrounding flow. Here we aim to decouple these two mechanisms through a combination of field and laboratory experiments. In this study, a wall jet and a stream of bubbles are used to create two flows near a submerged solid surface where biofouling occurs. The flow structure characteristics were recorded using PIV. This experimental analysis allows for us to compare the efficacy of each flow relative to its flow parameters. Exploration of the mechanisms at play in the prevention of biofouling by use of rising bubbles provides a foundation to predict and optimize this antifouling technique under various conditions.

  2. A classification of martian gullies from HiRISE imagery

    NASA Astrophysics Data System (ADS)

    Auld, Katherine S.; Dixon, John C.

    2016-10-01

    Due to the large and varied population of gullies observed in Mars High Resolution Imaging Science Experiment (HiRISE) imagery that exhibit diverse characteristics, this paper develops a classification of martian gullies based on their morphological characteristics. This provides a firmer foundation for future investigation of the genesis of different gully morphologies. The Mars Reconnaissance Orbiter (MRO) image catalog on the HiRISE website was examined and 869 images, chosen from the first 25,000 orbits, show a wide variety of gully morphologies. The images were analyzed using ENVI 4.4 and ENVI Zoom and the gullies were cataloged and divided into groups based on the presence and character of the dominant morphological components of alcove, channel, and apron associated with each gully. 7519 gullies were identified in the images and the length and width of the components were measured in ENVI to facilitate classification. Seven classes were developed based on morphology.

  3. Critique of DELFIC's cloud rise module. Final report

    SciTech Connect

    Jodoin, V.J.

    1993-05-01

    This report discusses the Cloud Rise Module (CRM) of the Defense Land Fallout Interpretive Code (DELFIC), the DOD's reference fallout code. The first section discusses the errors found in the 1979 documentation. These errors have been corrected and further research by the Air Force Institute of Technology will include the corrections listed in this section. The second section will discuss the use of Mathematica in simulating the CRM. This part of the report will describe how a higher level language was used to review the results of DELFIC's CRM and uncover some problem areas. The final part of this report will describe further work as planned by the author in improving the CRM of DELFIC. DELFIC, Nuclear clouds, Fallout, Cloud rise.

  4. HiRISE Observations of Dynamical Phenomena on Mars

    NASA Astrophysics Data System (ADS)

    Hansen, Candice; Thomas, Nicolas; McEwen, Alfred

    Candice Hansen, candice.j.hansen@jpl.nasa.gov Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States Candice Hansen, candice.j.hansen@jpl.nasa.gov Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, United States Nicolas Thomas, nicolas.thomas@space.unibe.ch University of Bern, Bern, Switzerland Alfred McEwen, mcewen@pirl.lpl.arizona.edu Lunar and Planetary Laboratory, Tucson, Arizona, United States The HiRISE Team Alan Delamere Eric Eliason John Grant Virginia Gulick Kenneth Herkenhoff Laszlo Keszthelyi Randolph Kirk Michael Mellon Steven Squyres Cathy Weitz Chris Okubo Shane Byrne Patrick Russell The presentation will provide a review of recent observations by the HiRISE imaging system onboard the Mars Reconnaissance Orbiter. Emphasis will be placed on dynamical phenomena such as avalanches, dune motion, and jet activity at the poles.

  5. China's rise as a major contributor to science and technology.

    PubMed

    Xie, Yu; Zhang, Chunni; Lai, Qing

    2014-07-01

    In the past three decades, China has become a major contributor to science and technology. China now employs an increasingly large labor force of scientists and engineers at relatively high earnings and produces more science and engineering degrees than the United States at all levels, particularly bachelor's. China's research and development expenditure has been rising. Research output in China has been sharply increasing since 2002, making China the second largest producer of scientific papers after the United States. The quality of research by Chinese scientists has also been improving steadily. However, China's rise in science also faces serious difficulties, partly attributable to its rigid, top-down administrative system, with allegations of scientific misconduct trending upward.

  6. Acceleration of Sea Level Rise Over Malaysian Seas from Satellite Altimeter

    NASA Astrophysics Data System (ADS)

    Hamid, A. I. A.; Din, A. H. M.; Khalid, N. F.; Omar, K. M.

    2016-09-01

    Sea level rise becomes our concern nowadays as a result of variously contribution of climate change that cause by the anthropogenic effects. Global sea levels have been rising through the past century and are projected to rise at an accelerated rate throughout the 21st century. Due to this change, sea level is now constantly rising and eventually will threaten many low-lying and unprotected coastal areas in many ways. This paper is proposing a significant effort to quantify the sea level trend over Malaysian seas based on the combination of multi-mission satellite altimeters over a period of 23 years. Eight altimeter missions are used to derive the absolute sea level from Radar Altimeter Database System (RADS). Data verification is then carried out to verify the satellite derived sea level rise data with tidal data. Eight selected tide gauge stations from Peninsular Malaysia, Sabah and Sarawak are chosen for this data verification. The pattern and correlation of both measurements of sea level anomalies (SLA) are evaluated over the same period in each area in order to produce comparable results. Afterwards, the time series of the sea level trend is quantified using robust fit regression analysis. The findings clearly show that the absolute sea level trend is rising and varying over the Malaysian seas with the rate of sea level varies and gradually increase from east to west of Malaysia. Highly confident and correlation level of the 23 years measurement data with an astonishing root mean square difference permits the absolute sea level trend of the Malaysian seas has raised at the rate 3.14 ± 0.12 mm yr-1 to 4.81 ± 0.15 mm yr-1 for the chosen sub-areas, with an overall mean of 4.09 ± 0.12 mm yr-1. This study hopefully offers a beneficial sea level information to be applied in a wide range of related environmental and climatology issue such as flood and global warming.

  7. Sea-level rise impacts on scour at coastal bridges in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Froehlich, D.

    2003-04-01

    Sea level, which has risen by 10 to 20 cm (4 to 8 inches) in the past century along most of the US coastline, is projected to rise an additional 48 cm (19 inches) by 2100, with a possible range of 13 cm to 95 cm (26 to 37 inches). Eustatic increases in sea level are being caused largely by melting glaciers and ice sheets on land, and thermal expansion of ocean water. Sea level rise will continue to accelerate beyond 2100 as a result of the great amount of time needed for oceans and ice sheets to approach equilibrium under the long-term perturbations anticipated with climate change. Tropical storms, hurricanes, typhoons, and similar extreme atmospheric phenomena along the southeastern coast of the US generate high winds that in turn create large waves and currents. Resulting storm surges can temporarily raise water levels by as much as 23 feet (7 meters) above normal. Although these events are sporadic, they are a primary cause of scour at bridges along most of the US coastline. Even if storm magnitudes and frequencies do not change as a result of global warming, an important impact of future storms, whether tropical or extratropical, will be their superposition on a rising sea level. Thus sea-level rise will increase impacts to the coast by a storm of a given magnitude by increasing the baseline water level for extreme storms. Because many coastal bridges were designed to withstand erosion produced by storm surges having 1 percent annual chance of occurrence (that is, 100-year storm surge), as sea levels increase the statistics used to design these structures changes. For example, a 50-year storm surge following an increase in sea level could scour a bridge as severely as would the current 100-year storm surge. Impacts of rising sea levels on scour at coastal bridges in the southeastern US are illustrated by an analysis of the Cape Fear River estuary system in North Carolina. A numerical model of fully-coupled flow and sediment transport in open channels was used

  8. Space-based Observational Constraints for 1-D Plume Rise Models

    NASA Technical Reports Server (NTRS)

    Martin, Maria Val; Kahn, Ralph A.; Logan, Jennifer A.; Paguam, Ronan; Wooster, Martin; Ichoku, Charles

    2012-01-01

    We use a space-based plume height climatology derived from observations made by the Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard the NASA Terra satellite to evaluate the ability of a plume-rise model currently embedded in several atmospheric chemical transport models (CTMs) to produce accurate smoke injection heights. We initialize the plume-rise model with assimilated meteorological fields from the NASA Goddard Earth Observing System and estimated fuel moisture content at the location and time of the MISR measurements. Fire properties that drive the plume-rise model are difficult to estimate and we test the model with four estimates for active fire area and four for total heat flux, obtained using empirical data and Moderate Resolution Imaging Spectroradiometer (MODIS) re radiative power (FRP) thermal anomalies available for each MISR plume. We show that the model is not able to reproduce the plume heights observed by MISR over the range of conditions studied (maximum r2 obtained in all configurations is 0.3). The model also fails to determine which plumes are in the free troposphere (according to MISR), key information needed for atmospheric models to simulate properly smoke dispersion. We conclude that embedding a plume-rise model using currently available re constraints in large-scale atmospheric studies remains a difficult proposition. However, we demonstrate the degree to which the fire dynamical heat flux (related to active fire area and sensible heat flux), and atmospheric stability structure influence plume rise, although other factors less well constrained (e.g., entrainment) may also be significant. Using atmospheric stability conditions, MODIS FRP, and MISR plume heights, we offer some constraints on the main physical factors that drive smoke plume rise. We find that smoke plumes reaching high altitudes are characterized by higher FRP and weaker atmospheric stability conditions than those at low altitude, which tend to remain confined

  9. Long-rising Type II supernovae from Palomar Transient Factory and Caltech Core-Collapse Project

    NASA Astrophysics Data System (ADS)

    Taddia, F.; Sollerman, J.; Fremling, C.; Migotto, K.; Gal-Yam, A.; Armen, S.; Duggan, G.; Ergon, M.; Filippenko, A. V.; Fransson, C.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Leloudas, G.; Leonard, D. C.; Lunnan, R.; Masci, F. J.; Moon, D.-S.; Silverman, J. M.; Wozniak, P. R.

    2016-04-01

    Context. Supernova (SN) 1987A was a peculiar hydrogen-rich event with a long-rising (~84 d) light curve, stemming from the explosion of a compact blue supergiant star. Only a few similar events have been presented in the literature in recent decades. Aims: We present new data for a sample of six long-rising Type II SNe (SNe II), three of which were discovered and observed by the Palomar Transient Factory (PTF) and three observed by the Caltech Core-Collapse Project (CCCP). Our aim is to enlarge this small family of long-rising SNe II, characterizing their differences in terms of progenitor and explosion parameters. We also study the metallicity of their environments. Methods: Optical light curves, spectra, and host-galaxy properties of these SNe are presented and analyzed. Detailed comparisons with known SN 1987A-like events in the literature are shown, with particular emphasis on the absolute magnitudes, colors, expansion velocities, and host-galaxy metallicities. Bolometric properties are derived from the multiband light curves. By modeling the early-time emission with scaling relations derived from the SuperNova Explosion Code (SNEC) models of MESA progenitor stars, we estimate the progenitor radii of these transients. The modeling of the bolometric light curves also allows us to estimate other progenitor and explosion parameters, such as the ejected 56Ni mass, the explosion energy, and the ejecta mass. Results: We present PTF12kso, a long-rising SN II that is estimated to have the largest amount of ejected 56Ni mass measured for this class. PTF09gpn and PTF12kso are found at the lowest host metallicities observed for this SN group. The variety of early light-curve luminosities depends on the wide range of progenitor radii of these SNe, from a few tens of R⊙ (SN 2005ci) up to thousands (SN 2004ek) with some intermediate cases between 100 R⊙ (PTF09gpn) and 300 R⊙ (SN 2004em). Conclusions: We confirm that long-rising SNe II with light-curve shapes closely

  10. Recruitment and Retention of Indians in Science and Engineering (RISE)

    NASA Technical Reports Server (NTRS)

    Karnawat, Sunil

    1997-01-01

    Fifteen students from Turtle Mountain Community College were selected to participate in activities of the RISE project last summer. Eight students successfully completed project activities and received stipends for their participation. These eight students are (1) Jamie Gable, (2) John Morin, (3) Patrick Belgarde, (4) Jason Laducer, (5) Alex Johnson, (6) Eric Houle, (7) Gary Renault, and (8) Kenny DeCoteau. In the fall of 1998, Jamie Gable and Gary Renault went to North Dakota State University to pursue their undergraduate degrees in mechanical engineering, and John Morin and Alex Johnson joined the University of North Dakota's electrical engineering and industrial technology programs, respectively. Remaining four students will continue to participate in the RISE activities this year and transfer to the universities next year. Seven students who failed to complete the RISE project activities during the current award period are encouraged to participate again this fall. The RISE students were enrolled in a special course called "Introduction to Engineering Materials." The project director, Dr. Kamawat, taught the course on Saturdays and Sundays. Theoretical and mathematical background on engineering materials and careers in various engineering professions were discussed in this course. The students attended guest lectures given by engineers and professors and visited local industries. In addition, the students went to North Dakota State University (NDSU) at Fargo, ND, and the University of Minnesota (UMN) at Minneapolis, MN, to tour their engineering departments. At NDSU, they conducted laboratory tests on various engineering materials, such as concrete, steel, wood, plastics, and carbon composites. The students investigated the mechanical behavior of these materials under various loading conditions, collected data, interpreted data, identified possible errors, determined the mechanical properties, and wrote reports on their findings. The students created posters

  11. Active Mars Revealed through HiRISE DTMs and Orthoimages

    NASA Astrophysics Data System (ADS)

    Mattson, Sarah; McEwen, Alfred S.; Bridges, Nathan; Byrne, Shane; Chojnacki, Matthew; Daubar, Ingrid; Dundas, Colin; Russell, Patrick

    2014-11-01

    Before the arrival of the Mars Reconnaissance Orbiter (MRO) with the High-Resolution Imaging Science Experiment (HiRISE), the amount of surface activity on Mars was not well known. HiRISE repeat imaging (often at ~30 cm/pixel), combined with the ability to take stereo images and generate high resolution Digital Terrain Models (DTMs) reveals the many types of surface processes that are currently active on Mars. Examples of active processes on Mars studied with HiRISE data include aeolian activity [Bridges et al., 2012, Nature 485; Chojnacki et al., 2014, Icarus 232], Recurring Slope Lineae (RSL) [McEwen et al., 2011, Science 333; 2014, Nature Geoscience 7], active gullies [Dundas et al., 2012, Icarus 220], polar processes [Hansen et al., 2011, Science 331; Portyankina et al. 2013, AGU], new impacts [Byrne et al., 2009, Science 325; Daubar et al., 2013, Icarus 225; Dundas et al., 2014, JGR 119], and north polar scarp avalanches [Russell et al., 2008, GRL 35, 2014, LPSC]. These studies utilize images from multiple Mars years and seasons. We generate animated gifs with sequences of orthorectified images to analyze temporal changes (see http://www.uahirise.org/sim/). HiRISE DTMs and orthoimages can be used to quantitatively map and record changes in geospatial software. More than 200 DTMs and 400 orthoimages are available through the Planetary Data System (see http://uahirise.org/dtm). Three-band color (blue-green, red, and near infrared) orthoimages are also available in many cases. The ability to monitor the surface of Mars at high spatial and temporal resolution provides insight into seasonal and annual changes, further increasing our understanding of Mars as an active planet.

  12. Global warming, sea-level rise, and coastal marsh survival

    USGS Publications Warehouse

    Cahoon, Donald R.

    1997-01-01

    Coastal wetlands are among the most productive ecosystems in the world. These wetlands at the land-ocean margin provide many direct benefits to humans, including habitat for commercially important fisheries and wildlife; storm protection; improved water quality through sediment, nutrient, and pollution removal; recreation; and aesthetic values. These valuable ecosystems will be highly vulnerable to the effects of the rapid rise in sea level predicted to occur during the next century as a result of global warming.

  13. Basement structures over Rio Grande Rise from gravity inversion

    NASA Astrophysics Data System (ADS)

    Constantino, Renata Regina; Hackspacher, Peter Christian; de Souza, Iata Anderson; Lima Costa, Iago Sousa

    2017-04-01

    The basement depth in the Rio Grande Rise (RGR), South Atlantic, is estimated from combining gravity data obtained from satellite altimetry, marine surveys, bathymetry, sediment thickness and crustal thickness information. We formulate a crustal model of the region by inverse gravity modeling. The effect of the sediment layer is evaluated using the global sediment thickness model of National Oceanic and Atmospheric Administration (NOAA) and fitting the sediment compaction model to observed density values from Deep Sea Drilling Project (DSDP) reports. The Global Relief Model ETOPO1 and constraining data from seismic interpretation on crustal thickness are integrated in the inversion process. The modeled Moho depth values vary between 6 and 27 km over the area, being thicker under the RGR and also in the direction of São Paulo Plateau. The inversion for the gravity-equivalent basement topography is applied to gravity residual data, which is free from the gravity effect of sediments and from the gravity effect of the estimated Moho interface. We find several short-wavelengths structures not present in the bathymetry data. Our model shows a rift crossing the entire Rio Grande Rise deeper than previously presented in literature, with depths up to 5 km in the East Rio Grande Rise (ERGR) and deeper in the West Rio Grande Rise (WRGR), reaching 6.4 km. An interesting NS structure that goes from 34°S and extends through de São Paulo Ridge may be related to the South Atlantic Opening and could reveal an extinct spreading center.

  14. The Rise and Development of Sendero Luminoso in Peru

    DTIC Science & Technology

    1992-03-27

    AgenCY. THE RISE AND DEVELOPMENT OF MA0 SENDERO LUMINOSO IN PERU * BY Lieutenant Colonel Charles R. DeWitt United States Army DISTRIBUTION STATEMENT...CLASSIFICATION AUTHORITY 3 DISTRIBUTION /AVAILABILITY OF REPORT 2b. DECLASSIFICATION / DOWNGRADING SCHEDULE e ..trib uti 19 tintpir-i.l o pbi 4. PERFORMING...LUMINOSO IN PERU An Individual Study Project by Lieutenant Colonel Charles R. DeWitt United States Army Mr. James E. Trinnaman Jr. Project Advisor U.S

  15. Response of surge protection devices to fast rising pulses

    NASA Technical Reports Server (NTRS)

    Mindel, I. N.

    1980-01-01

    Two types of lightning protection modules incorporating leadless (pill type) Zener like devices were evaluated with regard to their ability to suppress EMP induced transients. Two series of tests were performed to evaluate the ability of these modules to react to fast rate of rise ( 1Kv/ns) transients, and the attenuation introduced and the ability to limit damped sinusoid pulses which may be induced due to an EMP resulting from a nuclear detonation.

  16. Probabilistic reanalysis of twentieth-century sea-level rise.

    PubMed

    Hay, Carling C; Morrow, Eric; Kopp, Robert E; Mitrovica, Jerry X

    2015-01-22

    Estimating and accounting for twentieth-century global mean sea level (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records--employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change--have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 1990. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques and find a rate of GMSL rise from 1901 to 1990 of 1.2 ± 0.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records.The increase in rate relative to the 1901-90 trend is accordingly larger than previously thought; this revision may affect some projections of future sea-level rise.

  17. Low power, high voltage power supply with fast rise/fall time

    NASA Technical Reports Server (NTRS)

    Bearden, Douglas B. (Inventor)

    2007-01-01

    A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

  18. The rise of the FGFR inhibitor in advanced biliary cancer: the next cover of time magazine?

    PubMed

    Rizvi, Sumera; Borad, Mitesh J

    2016-10-01

    Cholangiocarcinomas (CCAs) are heterogeneous tumors arising from the biliary tract with features of cholangiocyte differentiation. CCAs are aggressive tumors with limited treatment options and poor overall survival. Only a subset of CCA patients with early stage disease can avail potentially curative treatment options. For advanced biliary tract tumors, currently there are limited effective treatment modalities. Recent advances have provided greater insight into the genomic landscape of CCAs. The fibroblast growth factor receptor (FGFR) pathway is involved in key cellular processes essential to survival and differentiation. Accordingly, aberrant FGFR signaling has significant oncogenic potential. Recent discovery of FGFR2 gene fusions in CCA has heightened interest in FGFR inhibition in advanced biliary tract cancer. These findings have served as a catalyst for ongoing clinical investigation of FGFR inhibition in CCA patients with various FGFR signaling abnormalities. Herein, we review FGFR aberrations in CCA and their prognostic implications, FGFR targeting as a viable therapeutic option in advanced biliary tract malignancies, and future directions for development of combination approaches utilizing FGFR inhibition.

  19. Laser pumping of thyristors for fast high current rise-times

    DOEpatents

    Glidden, Steven C.; Sanders, Howard D.

    2013-06-11

    An optically triggered semiconductor switch includes an anode metallization layer; a cathode metallization layer; a semiconductor between the anode metallization layer and the cathode metallization layer and a photon source. The semiconductor includes at least four layers of alternating doping in the form P-N-P-N, in which an outer layer adjacent to the anode metallization layer forms an anode and an outer layer adjacent the cathode metallization layer forms a cathode and in which the anode metallization layer has a window pattern of optically transparent material exposing the anode layer to light. The photon source emits light having a wavelength, with the light from the photon source being configured to match the window pattern of the anode metallization layer.

  20. The rise of the FGFR inhibitor in advanced biliary cancer: the next cover of time magazine?

    PubMed Central

    Rizvi, Sumera

    2016-01-01

    Cholangiocarcinomas (CCAs) are heterogeneous tumors arising from the biliary tract with features of cholangiocyte differentiation. CCAs are aggressive tumors with limited treatment options and poor overall survival. Only a subset of CCA patients with early stage disease can avail potentially curative treatment options. For advanced biliary tract tumors, currently there are limited effective treatment modalities. Recent advances have provided greater insight into the genomic landscape of CCAs. The fibroblast growth factor receptor (FGFR) pathway is involved in key cellular processes essential to survival and differentiation. Accordingly, aberrant FGFR signaling has significant oncogenic potential. Recent discovery of FGFR2 gene fusions in CCA has heightened interest in FGFR inhibition in advanced biliary tract cancer. These findings have served as a catalyst for ongoing clinical investigation of FGFR inhibition in CCA patients with various FGFR signaling abnormalities. Herein, we review FGFR aberrations in CCA and their prognostic implications, FGFR targeting as a viable therapeutic option in advanced biliary tract malignancies, and future directions for development of combination approaches utilizing FGFR inhibition. PMID:27747092